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The aim of this work is to highlight numerous studies proving that the intake of PCBs by inhalation cannot be neglected, in particular in heavily industrialized areas and where the concentration of PCBs in the environmental matrices is particularly high.
Partial least squares PLS was used to build the regression model. Topological indices were used as molecular descriptors. The results showed that topological indices can be very useful to predict the K OW. Relative effect potency estimates of dioxin-like activity for dioxins, furans, and dioxin-like PCBs in adults based on two thyroid outcomes. Toxic equivalency factors TEFs are an important component in the risk assessment of dioxin-like human exposures.
At present, this concept is based mainly on in vivo animal experiments using oral dosage. Consequently, the current human TEFs derived from mammalian experiments are applicable only for exposure situations in which oral ingestion occurs. Nevertheless, these "intake" TEFs are commonly-but incorrectly-used by regulatory authorities to calculate "systemic" toxic equivalents TEQs based on human blood and tissue concentrations, which are used as biomarkers for either exposure or effect.
We sought to determine relative effect potencies REPs for systemic human concentrations of dioxin-like mixture components using thyroid volume or serum free thyroxine FT4 concentration as the outcomes of interest. We used a benchmark concentration and a regression- based approach to compare the strength of association between each dioxin-like compound and the thyroid end points in adults residing in an organochlorine-polluted area of eastern Slovakia.
REPs calculated from thyroid volume and FT4 were similar. The calculated REPs were mostly within the minimum and maximum values for in vivo REPs derived by other investigators. Our REPs calculated from thyroid end points realistically reflect human exposure scenarios because they are based on chronic, low-dose human exposures and on biomarkers reflecting body burden. Compared with previous results, our REPs suggest higher sensitivity to the effects of dioxin-like compounds.
Bioremediation of PCBs. CRADA final report. The work was conducted over three years, and this report summarizes ORNL's effort. The sequential treatment resulted in PCB products with fewer chlorines and shorter halflives in humans compared with either anaerobic or aerobic treatment alone. The study was expected to lead to a technology applicable to a field experiment that would be performed on a DOE contaminated site.
Klasson, K. Chemical Technology Div. Deeper insights into PCBs in orcas. PCB-containing equipment by and perform environmentally sound waste management by This means nonetheless that PCBs will continue to leach into the environment over the next decade.
Given present-day observed reproductive failure in several killer whale populations we must urgently reduce We believe the choice for international PCB mitigation is timely in order to not lose this canary in the coalmine To understand the behavior and sources of polychlorinated biphenyls PCBs in ambient air, gaseous and particulate phase concentrations were measured at Yokohama City, Japan, during March and February The gas-particle partition coefficient K p was obtained as a function of temperature.
As a result, the partition ratio of gaseous and particulate phase PCBs can be estimated for an arbitrary temperature. The concentrations of congeners between tetra-CBs and deca-CB were used as input variables, and three PCs with eigenvalue more than 10 were obtained. The principal component 1 PC 1 accounted for The concentrations of PCB congeners were strongly related with PC 1 which showed high correlation with temperature. PC 2 accounted for This study is one of the first in.
Electrokinetic delivery of persulfate to remediate PCBs polluted soils: effect of injection spot. Persulfate- based in situ chemical oxidation ISCO is a promising technique for the remediation of organic compounds contaminated soils. Electrokinetics EK provides an alternative method to deliver oxidants into the target zones especially in low permeable-soil. In this study, the flexibility of delivering persulfate by EK to remediate polychlorinated biphenyls PCBs polluted soil was investigated.
The results showed that high dosage of persulfate could be delivered into S4 section near cathode by electroosmosis when persulfate was injected from anode, In contrast, only These results indicated that the electroosmotic flow is more effective for the transportation of persulfate into soil. The addition of persulfate from both electrodes did not significantly facilitate the PCBs oxidation as well as the treatment of electrical field reversion, the reinforced negative depolarization function occurring in the cathode at high current consumed most of the oxidant.
This book presents a review of all aspects of the physical behavior of one contaminant PCBs in one aquatic environment Great Lakes. This book not only treats this topic extensively, but also serves as a model for treatment of other contaminants in other aquatic environments. This book focuses on the physical rather than biological aspects of PCBs. This focus does not imply a lack of concern for the biosphere or for the effects or toxicology of PCBs ; instead, it represents an attempt to tackle a smaller problem of manageable proportions.
The environmental fate of PCBs is largely controlled by physical processes, with biodegradation of lower chlorine congeners as the outstanding exception. A comprehensive congener specific evaluation of polychlorinated biphenyls PCBs and polychlorinated naphthalenes PCNs in the atmosphere was conducted across East Asia in spring , applying polyurethane foam PUF disk passive air sampler PAS as monitoring device.
Relative to reported data from , the present results suggest that air PCBs concentrations have not changed much in Japan and Korea, while it has increased by one order of magnitude in China. From principal component analysis , combustion emerged highly culpable in contemporary emissions of both PCBs and PCNs across the East Asian sub-region.
Hydroxylated PCBs in abiotic environmental matrices. Precipitation and surface waters. Darling, C. OH- PCBs can compete with thyroxine for binding sites on transthyretin, one of the three main thyroid hormone transport proteins in mammals1. This presentation describes preliminary studies on the presence of OH- PCBs in abiotic samples and comparisons of congener patterns with biological samples.
We have previously shown that OHPCBs were present in lake trout from the Great Lakes and nearby large lakes as well as in nearshore environments. Decontamination of PCBs -containing soil using subcritical water extraction process. Polychlorinated biphenyls PCBs are one of the excision compounds listed at the Stockholm convention in Although their use has been heavily restricted, PCBs can be found in some specific site-contaminated soils.
Either removal or destruction is required prior to disposal. The subcritical water extraction SCWE of organic hazardous compounds from contaminated soils is a promising technique for hazardous waste contaminated-site cleanup. The effects of temperature and treatment time on removal efficiency have been determined.
In the SCWE experiments, a removal percentage of The mass removal efficiency of low-chlorinated species was higher than high-chlorinated congeners at lower temperatures, but it was oppositely observed at higher temperatures because the lower chlorinated congeners are formed by dechlorination of higher chlorinated congeners. Several degradation products including mono- and di-chlorinated biphenyls, oxygen-containing aromatic compounds, and small-size hydrocarbons were identified in the effluent water, which were not initially present in the contaminated soil.
Comparison of supercritical fluid extraction and Soxhlet extraction for the determination of PCBs in seaweed samples. The efficiency of supercritical fluid extraction for the determination of 12 polychlorinated biphenyls from algae samples is compared to Soxhlet extraction.
Analytical detection limits for the individual congeners ranged from 0. Recovery was tested for both methods using standard addition procedure. Method precision for Soxhlet extraction yield comparable results, SFE offers the advantage of detecting all PCBs studied at lower concentrations, reducing extraction time, and reducing the amount of solvents needed.
The optimized methods were applied to the analysis of three real seaweed samples, except for PCB the concentrations of all PCBs were low or below the detection limits. The levels of PCB found in sample 1 were 6. Assessment of gold and silver in assorted mobile phone printed circuit boards PCBs : Original article.
Demand for gold and silver has been escalating with increasing usage of electronic equipment globally. Around The waste comprise glass, plastics, wires, batteries, PCBs , metal casing, etc. The PCB is composed of precious metals, which creates immense purpose for recycling and recovery. This paper characterises and assesses the recoverable metallic fraction of gold and silver from PCBs of mobile phones. The methodology is based on dismantling of the mobile handset and subjecting the PCBs to roasting and acid digestion.
The digested samples were analysed by atomic absorption spectroscopy and the content of gold and silver in the PCBs was to be found in the range of 0. A comprehensive worldwide literature review of blood levels of dioxins and dioxin-like compounds in non-exposed adult general populations was performed. Weighted multiple regression analyses adjusted for year, subject's age, type of sample analyzed, method used for values below detection limit, and central tendency measure used were performed for each congener and standardized TEQs log-transformed.
We identified studies regarding 29, subjects of 26 countries. Year of blood collection ranged from to The studies reporting congener levels In adjusted analyses, European countries showed higher levels of most dioxin-like congeners and TEQs. A strong positive association of subjects' age with most congeners and with TEQ values was found, confirming previous findings. Only some mono-ortho- PCBs showed clear significant declines.
In interpreting these findings, it should be considered that for dioxin-like PCBs the analysis period was shorter 17 years , since these compounds were first measured in Biological data on PCBs in animals other than man. Experimental studies have shown that PCBs have a toxicity to mallards, pheasants, bobwhite quail, coturnix quail, red-winged blackbirds, starlings, cowbirds, and grackles that is of the same order as the toxicity of DDE to these species.
Overt signs of poisoning also are similar to those caused by compounds of the DDT group. Toxic effects of DDE and Aroclor to coturnix chicks were additive, but not synergistic. PCBs containing higher percentages of chlorine are more toxic to birds than those containing lower percentages. PCBs of foreign manufacture contained contaminants to an extent that greatly increased their toxicity. Residues of PCBs in the brains of birds killed by these compounds measure in the hundreds of parts per million.
PCBs may have contributed to mortality of some birds in the field. Toxicity to insects of PCBs of different degrees of chlorination is the reverse of the pattern in birds: the lower chlorinations are more toxic to insects. Shrimp are very sensitive to PCBs and most will die as a result of day exposure to a concentration of 5 ppb. PCBs also inhibit shell growth of oysters.
Crabs are less sensitive; all accumulate residues to many times the concentrations in the water, and a test with crabs showed that they lost the residues very slowly. Growth of certain species of marine diatoms was experimentally inhibited by PCBs , but algae were not affected. The small marine crustacean, Gammarus, is sensitive to PCBs in concentrations of thousandths to tenths of a part per billion. Exposure to 5 ppb of Aroclor caused mortality of two species of fish in days.
Onset of death was delayed and was accompanied by fungus-like lesions. Rainbow trout were quickly killed by terphenyls at 10 ppb under normal oxygen conditions and at 2 ppb with reduced oxygen. Guidance on the management of polychlorinated biphenyls PCBs. Polychlorinated biphenyls PCBs are a class of synthetic organic chemicals including known isomers, each with from 1 to 10 chlorine atoms on a biphenyl ring.
PCBs have a number of desirable properties for industrial applications including thermal stability, flame retardance, and low vapor pressure. Because of these properties, PCBs were widely used as dielectric fluid in electrical equipment such as utility transformers and capacitors. PCBs were also extensively used in hydraulic fluid and heat transfer fluid, in gaskets, as additives in cutting oils and lubricant, and in a variety of other uses.
The TSCA regulations allow continued use of PCBs provided that the use is totally enclosed and does not pose a risk to human health or the environment. This guidance document uses graphics and flow charts where possible to present the TSCA regulations according to management activities such as use, storage, disposal, and spill cleanup. The document is designed to be read on an as-needed basis; that is, each chapter can stand alone or may be read in combination with others to help the reader determine the regulations relevant to his or her individual situation and needs.
Every attempt has been made to include the requirements of other statutes and regulations that apply to PCB materials and provide references for the reader to consult for additional information. Decomposition of PCBs in oils using gamma radiolysis.
This paper investigates the radiolysis of the polychlorinated biphenyls PCBs in several oil matrices. The results of mechanism and kinetic studies in isooctane are presented. The decomposition of PCBs in isooctane is shown to occur by reductive dechlorination due to electron capture and to proceed with pseudo-first-order kinetics. The rate is dependent on the initial PCB concentration. Electron capture detection gas chromatograms confirm that dechlorination also occurs with commercial Aroclor PCBs in irradiated transformer and hydraulic oils.
The results of a demonstration experiment involving PCB contaminated waste hydraulic oils are presented. Atmospheric concentration characteristics and gas-particle partitioning of PCBs in a rural area of eastern Germany. Atmospheric concentrations of polychlorinated biphenyls PCBs were measured in 14 successive daytime and nighttime air samples collected from Melpitz, a rural site in eastern Germany.
Composition of individual congeners closely resembled those of Clophen A30 and Aroclor Partial vapor pressures of PCBs were well correlated with temperature and the steep slopes obtained from Clausius-Clapeyron plots to indicated that evaporation from adjacent land surfaces still controls the atmospheric levels of these pollutants. Spatial gradients of polychlorinated biphenyls PCBs and organochlorine pesticides.
Bioaccumulation dynamics of polychlorinated biphenyls PCBs and organochlorine pesticides. National Oceanic and Atmospheric Administration, Department of Commerce — Bioaccumulation dynamics of polychlorinated biphenyls PCBs and organochlorine pesticides was examined in young-of-the-year bluefish from seven sub-estuaries of New Polychlorinated-biphenyls PCBs were introduced in the late s and used until the s when they were banned in most countries due to evidence of environmental build-up and possible adverse health effects.
However they still persist in the environment, indoors and in humans. Indoor air To date, no epidemiological studies have assessed the health effects from exposure to semi-volatile PCBs in the indoor environment. We found These latter findings are the first to demonstrate a sexual.
Human exposure to bioaccumulable organochlorine compounds is a reality, not only because of the known presence in tissues of the residue of historic contaminants such as DDT and other pesticides, but also because of the risk of current exposure to compounds still in use, such as lindane, endosulphan and polychlorinated biphenyls or PCBs , among others. The case of the PCBs is of particular importance. Although their production was prohibited due to their hazardous nature, persistence and envir This reference method deals with the determination of DDTs and PCBs in marine environmental samples using high resolution gas chromatography.
Several other halogenated pesticides and other electron capturing organic compounds may be present in samples and many of these may also be determined by this method. Not all electron capturing residues will be resistant to all of the clean up procedures described here for the analysis of DTTs and PCBs. Therefore, additional information on the stability of some common pesticides using this methodology is also provided.
The high separation power of open tubular ''capillary'' columns allows the identification and quantification of many compounds in the complex mixtures occurring in environmental samples. This manual provides information on the theoretical and practical aspects of the use of these high resolution columns for the analysis of DDTs and PCBs in environmental samples.
For example, methods for obtaining these cleaned-up sample extracts from marine organisms are described in detail in UNEP Reference Method no. The change in the field of application by analysing by capillary rather than packed columns may be less dramatic for DDTs. However, with the increased separation, the possibilities of inaccurate analysis resulting from overlap with interfering compounds is reduced.
Most of these species are long-lived, so pollutant burdens may be integrated in some complex way over time. Birds have been suggested as useful organisms for monitoring pollutant levels. Traditionally such studies have been carried out with raptors such as osprey Pandion haliaetus , peregrine falcon Falco peregrinus , bald eagle Haliaetus leucocephalus , etc. In this paper we present the results of a monitoring study conducted on two raptor species, osprey Pandion haliaetus and red kite Milvus milvus , inhabiting a Mediterranean island Menorca, Spain.
These two species have different feeding habits; ospreys prey on fish and red kites feed on terrestrial species. This study constitutes a good opportunity to investigate if differences in feeding habits aquatic vs. The study was conducted in a non-destructive way, using only failed eggs, to avoid the damage of the population stability.
Eggs were collected during the period The analysis of organochlorine compounds was performed. PCDFs and non-ortho PCBs showed no such trends, implying that exposure of seals to these contaminants has been decreasing in recent years. Association of PCBs and allergies in children. Recently, the incidence rates of childhood allergies have been rising around the world. The presence of persistent chemical pollutants in the environment and exposure to air pollutants are often cited as potential causes of childhood allergies.
Accordingly, epidemiological studies of the associations between exposure to low levels of pollutants and adverse health effects are essential. However, at present no useful biomarkers for evaluating such associations have been developed. Thus, using a molecular epidemiological approach we planned to identify candidate biomarkers of pollutant-induced adverse health effects that can be used in children.
In asthmatic children, we found that the serum levels of several polychlorinated biphenyl PCB congener sub-types were significantly positively correlated with interleukin IL -8 mRNA expression, whereas in a sub-group of children who displayed positive immunoglobulin E IgE responses to milk or egg proteins IL mRNA expression was demonstrated to be useful for detecting the adverse health effects of environmental pollutants, particularly PCB congeners.
In conclusion, the mRNA expression levels of IL-8 and IL can be used to detect children who are at particular risk of adverse health events caused by environmental pollutants, especially PCBs. Consolidated PCBs [polychlorinated biphenyls] improves waste control. Consolidation of polychlorinated biphenyl PCB wastes is recommended for improving ownership control of wastes, eliminating PCB storage sites, and increasing cost-effectiveness of waste management.
In Ontario, sites receiving the waste must be owned by the waste generator and registered as a PCB site. All PCBs must be removed from a site with no contaminated materials or wastes left behind, which requires a thorough site assessment to identify wastes prior to removal, a sampling and analytical scheme if necessary, and an approved plan for site cleanup.
If large volumes of PCB-contaminated oil are involved, it may be cost-effective to put oil from several sites into bulk tanks and thus avoid the need to handle and decontaminate a large number of drums. With low volumes of oil, it may be possible to move the waste to another site where mobile PCB destruction is taking place.
It also may be possible to get approval to blend high-level PCB liquids with mineral oil to reduce the PCB concentration to a level where chemical decontamination is allowed. For large volumes of high-level PCB wastes, consolidation will be necessary simply because of the high costs of mobilizing an incinerator and the requirement for public hearings for each incineration project. To make such a project cost-effective, PCB wastes will have to be concentrated from a large geographic area.
Organochlorine pesticides and PCBs in air of southern Mexico Alegria, Henry A. Air samples were collected in southern Mexico in to determine the extent of contamination with organochlorine OC pesticides and polychlorinated biphenyls PCBs. Other prominent OC pesticides were endosulfans, toxaphene and lindane.
Pesticides detected in lower concentrations include chlordanes, dieldrin, and heptachlor. Proportions of DDT compounds suggested fresh use of DDT in some locations and a mix of fresh and aged residues at others. Concentrations of OC pesticides measured with passive samplers agreed well with those measured using high-volume samplers. Air back trajectory analysis suggests a complex pattern of regional atmospheric transport. PCBs with immersion tin finish - some experiences with lead-free reflow process.
Bukat, K. Substitution of lead-free solders in electronic assemblies requires changes in the conventional SnPb finishes of PCBs. Its main goal is to develop and implement the new technology of high solderability immersion tin for printed circuit boards at small and medium enterprises. The subject of the research was organic based immersion tin coating which would fulfil demands of SMT.
In the paper the results of reflow soldering process on PCBs covered by Ormecon registered immersion tin finish with using lead-free solder pastes will be described. Solderability of tin coating as well as wettability of lead-free solder paste will be presented. Levels in sediments were highly variable ranging between The direction of the air-seawater exchange was also explored by estimating seawater fugacity fractions of PAHs and PCBs.
For PAHs, the number of cases implying deposition Fugacity fractions were generally seawater and sediment levels were measured, implying that atmospheric deposition is an important mechanism affecting seawater and sediment PAH and PCB levels. Megson, David, E-mail: dpmegson hotmail. In human exposure studies involving Polychlorinated Biphenyls PCBs , it is useful to establish when an individual was potentially exposed.
Age dating PCB exposure is complex but assessments can be made because different PCB congeners have different residence times in the human body. The less chlorinated congeners generally tend to have shorter residence times because they are biotransformed and eliminated faster than more chlorinated congeners.
Therefore, the presence of high proportions of less chlorinated congeners is often indicative of recent exposure. Multivariate statistical analysis of the NHANES data showed that less chlorinated congeners are not always biotransformed faster than higher chlorinated compounds.
For example, PCB 28 a tri-chlorobiphenyl appears to be more resistant to biotransformation than PCB and penta-chlorobiphenyls. Congeners with chlorine atoms in the 2,5- and 2,3,6-positions appear to be more susceptible to biotransformation whereas congeners with chlorine bonds in the 2,3,4- 2,4,5- 3,4,5- and 2,3,4,5-positions appear to be more persistent. This work shows that future investigations to date PCB exposure would benefit from the analysis of a wide range of congeners, including the selection of key congeners based not only on the degree of chlorination but also on the positions of the chlorine atoms on the biphenyl.
This report presents the results of an in-depth assessment of historical releases of polychlorinated biphenyls PCBs from the Oak Ridge Reservation ORR and risks of adverse health effects in local populations. The project team 1 investigated releases of PCBs from the government sites, 2 evaluated PCB levels in environmental media in the area, 3 described releases of PCBs from other sources in the area, and 4 evaluated potential human exposures and health impacts associated with the historical presence of these contaminants in the environment.
PCBs were also used as cutting fluids for lubrication and cooling during metal working operations. Using information specific to the ORR, the project team estimated health risks for five off-site populations: 1 farm families that raised beef, dairy cattle, and vegetables on the flood plain of East Fork Poplar Creek EFPC ; 2 individuals who may have purchased beef and milk from cattle raised in the EFPC flood plain; 3 commercial and recreational fish consumers; 4 individuals that may have consumed turtles; and 5 users of surface water for recreation.
Noteworthy features of the study include a two-dimensional analysis of uncertainty and variability in the non-cancer risk estimates and an assessment of the uncertainty in PCB toxicology thresholds. Three or less excess cases of cancer would be expected to occur among individuals who consumed fish from these local waters since the 's.
Persons who consumed large amounts of fish from the Clinch R. Padula, D. Wild tuna are first caught in the Great Australian Bight in South Australian waters, and are then brought back to Port Lincoln where they are ranched in sea-cages before being harvested and exported to Japan.
This paper addresses the levels found in final harvested product. Details on levels found in other studies will be published elsewhere shortly. Full Text Available Human exposure to bioaccumulable organochlorine compounds is a reality, not only because of the known presence in tissues of the residue of historic contaminants such as DDT and other pesticides, but also because of the risk of current exposure to compounds still in use, such as lindane, endosulphan and polychlorinated biphenyls or PCBs , among others.
Although their production was prohibited due to their hazardous nature, persistence and environmental toxicity, a large number of equipments that contain considerable volumes of PCBs continue functioning. These equipments will reach the residual stage in the next few years, if not already, so that their correct disposal is necessary to avoid their release into the environment.
A National Plan for the decontamination and elimination of polychlorobiphenyls PCBs , polychloroterphenyls PCTs and the equipments that contain them was launched in Spain in This plan must be implemented taking full account of the possible effects of PBCs on the environment and human health and with the knowledge of those responsible for public health.
To determine the time related concentrations, we analyzed human milk for these substances at three time points between and Polychlorobiphenylols OH- PCBs , the dominating class of PCB metabolites, some of which are known to be strongly retained in human blood, were also included in the assessment. Methods We obtained milk from the Faroe Islands, where the population is exposed to POPs from their traditional diet which may include pilot whale blubber.
In addition to three pools, nine individual samples from the last time point were also analyzed. The nine individual samples showed great variation in PCB concentrations. The PBDE concentrations showed a clear increase over time, and their concentrations in human milk from are among the highest reported so far from Europe, with results of individual samples ranging from 4. The PBDEs show increasing concentrations over time. The OH-PCB metabolites are poorly transferred to human milk, which likely is related to their acidic character.
Trajectory Based Traffic Analysis. The analyses are developed in collaboration with traffic researchers and provide novel insights into conditions such as congestion, travel-time, choice of route, and traffic-flow. INTRA supports interactive point-and-click a INTRA supports interactive point With the web-site daisy.
Dechlorination of PCBs in the rhizosphere of switchgrass and poplar. Polychlorinated biphenyl PCB congeners PCB 52, 77, and singly and in mixture were spiked and aged in soil microcosms and subsequently planted with switchgrass Panicum virgatum or poplar Populus deltoids x nigra DN The planted reactors showed significantly greater reductions in PCB parent compounds when compared to unplanted systems after 32 weeks. There was evidence of reductive dechlorination in both planted and unplanted systems, but the planted microcosms with fully developed roots and rhizospheres showed greater biotransformation than the unplanted reactors.
These dechlorination products accounted for approximately all of the molar mass of parent compound lost. Based on the transformation products, reductive dechlorination pathways are proposed for rhizospheric biotransformation of PCB 52, 77, and This is the first report of rhizosphere biotransformation pathways for reductive dechlorination in marginally aerobic, intermittently flooded soil as evidenced by a mass balance on transformation products. Full Text Available Due to the emerging environmental issues related to e-waste there is concern about the quality of paddy soils near e-waste workshops.
The levels of heavy metals and PCBs and their influence on the enzyme activity and microbial community of paddy soils obtained from the immediate vicinity of an e-waste workshop were investigated in the present study. The results indicated that the heavy metal and PCB pollution did not differ significantly with an increase of the sampling point distances 5 to 30 m.
The concentration of Cd 2. The highest enzyme activity was found for urease compared to phosphatase and catalase, and a fluctuating trend in soil enzyme activity was observed in soils from different sampling sites. The microbial analysis revealed that there was no apparent correlation between the microbial community and the pollutants.
The present study suggests that the contamination stress of heavy metals and PCBs might have a slight influence on microbial activity in paddy soils. This study provides the baseline data for enzyme activities and microbial communities in paddy soil under the influence of mixed contamination. Influence of heavy metals and PCBs pollution on the enzyme activity and microbial community of paddy soils around an e-waste recycling workshop.
Due to the emerging environmental issues related to e-waste there is concern about the quality of paddy soils near e-waste workshops. Characterization of PCBs from computers and mobile phones, and the proposal of newly developed materials for substitution of gold, lead and arsenic. In this paper, we have analyzed parts of printed circuit board PCB and liquid crystal display LCD screens of mobile phones and computers, quantitative and qualitative chemical compositions of individual components, and complete PCBs were determined.
Differential thermal analysis DTA and differential scanning calorimetry DSC methods were used to determine the temperatures of phase transformations, whereas qualitative and quantitative compositions of the samples were determined by X-ray fluorescence spectrometry XRF , inductively coupled plasma optical emission spectrometry ICP-OES , and scanning electron microscopy SEM -energy dispersive X-ray spectrometry EDS analyses. The microstructure of samples was studied by optical microscopy.
Based on results of the analysis , a procedure for recycling PCBs is proposed. The emphasis was on the effects that can be achieved in the recycling process by extraction of some parts before the melting process. In addition, newly developed materials can be an adequate substitute for some of the dangerous and harmful materials, such as lead and arsenic are proposed, which is in accordance with the European Union EU Restriction of the use of certain hazardous substances RoHS directive as well as some alternative materials for use in the electronics industry instead of gold and gold alloys.
Tang, Xianjin; Hashmi, Muhammad Z. Developmental dental defects in children exposed to PCBs. Jan, J. Developing enamel is sensitive to a wide range of local and systemic disturbances. Because of the absolute metabolic stability of its structure, changes in enamel during its development are permanent in nature. Polychlorinated biphenyls PCB have been shown to disturb tooth development in experimental animals, but only limited amounts of data exist on their adverse effects in humans.
Dental changes such as mottled, chipped, carious, and neonatal teeth have been reported in accidentally exposed humans. Nevertheless, co-contamination with polychlorinated dibenzo-furans PCDFs was largely responsible for the overall toxicity4.
Alaluusua et al. In our previous study we have shown developmental dental defects in children exposed to PCBs alone6, suggesting that the developing human teeth are vulnerable to PCBs. In the Michalovce region of eastern Slovakia, PCBs from a chemical plant manufacturing Delors contaminated the surrounding district7.
The total serum PCB levels in samples from the general population there exceeded by several times the background levels in subjects living in a comparable unexposed Svidnik district. PCB levels in breast milk samples in the Michalovce region were the highest in Slovakia. The aim of this study was to evaluate the effects of long-term exposure to PCBs , measured at the individual level, on developmental dental defects in children in eastern Slovakia.
Pressurized liquid extraction PLE applying three extraction cycles, temperature and pressure, improved the efficiency of solvent extraction when compared with the classical Soxhlet extraction. Unlike data previously reported by other authors, results demonstrated that ASE using n-hexane as solvent and three extraction cycles, Such fast analytical methodology, having the best cost-efficiency ratio, will improve the control and will provide more information about the occurrence of dioxins and the levels of toxicity and thereby will contribute to increase human health.
This paper provided additional data related to a study conducted to determine chiral signatures of polychlorinated biphenyl PCBs in outdoor air and topsoil from urban, rural and semi-urban locations in the United Kingdom's West Midlands conurbation.
The study hypothesized that the ventilation of PCB-contaminated indoor air was a principal source of the racemic PCBs observed in outdoor air. Measurements of chiral signatures of PCBs in indoor air were measured. Chiral signatures of PCB and were expressed in terms of enantiomeric excess. Outdoor air and soil samples were collected from 10 sites located on a southwest to northeast transect of the conurbation at intervals of between 3 and 17 km.
Topsoil and air samples were collected on a monthly basis to examine seasonal variability. Passive air samplers were used to provide a time-integrated atmospheric signal over each sampling period. Twenty indoor air samples were collected using PUF disk samplers. All samples were then extracted, purified, and subjected to enantioselective gas chromatography and mass spectrometry GC-MS analysis. Results suggested that chiral signatures in outdoor air for all target PCBs were racemic at all locations, and confirmed earlier hypotheses that the ventilation of PCB-contaminated indoor air is the principal source of PCB contamination in the urban atmosphere.
It was concluded that actions to reduce PCB stocks remaining in use in indoor environments will result in a significant reduction in atmospheric concentrations. Compared to commercial eggs, levels were relatively high with a median of 4. A number of samples showed clearly elevated ndl-PCB levels with a median of 13 ng g -1 fat and a highest level of 80 ng g -1 fat.
Based on the congener patterns, former backyard burning of waste seems the most likely source for most eggs, with two exceptions where other sources contributed to the contamination. Similar is true for the ndl- PCBs. Intervention measures to reduce the intake of these contaminants by laying hens are advised. Forest filter effect versus cold trapping effect on the altitudinal distribution of PCBs : a case study of Mt. Gongga, eastern Tibetan Plateau. Mountains are observed to preferentially accumulate persistent organic pollutants POPs at higher altitude due to the cold condensation effect.
Forest soils characterized by high organic carbon are important for terrestrial storage of POPs. To investigate the dominant factor controlling the altitudinal distribution of POPs in mountainous areas, we measured concentrations of polychlorinated biphenyls PCBs in different environmental matrices soil, moss, and air from nine elevations on the eastern slope of Mt.
Gongga, the highest mountain in Sichuan Province on the Tibetan Plateau. Across all of the sampling sites, the average contribution of the forest filter effect FFE was greater than that of the mountain cold trapping effect based on principal components analysis and multiple linear regression. Our results deviate from the thermodynamic theory involving cold condensation at high altitudes of mountain areas and highlight the importance of the FFE.
One hundred and Fifty samples of human breast milk colostrums collected from donors patronizing a postnatal center in Nigeria were analyzed for the levels of lindane, total DDT and total PCBs residues. Donors were stratified with respect to factors that may affect accumulation of these compounds such as age, Attention: Docket ID Noteworthy impacts on fish, birds, and mammals EPA also is Temporal and spatial variation of polychlorinated biphenyls PCBs contamination in environmental compartments of highly polluted area in Central Russia.
This study highlights the fact that serious contamination from polychlorinated biphenyls PCBs still exists in Serpukhov City Russia. The research help to determine the temporal and year periods and spatial PCBs distribution in the environmental compartments of the studied region. Samples of soil, sediments, water and plants were analysed in order to establish their contamination levels.
The most recent data on the Serpukhov City's soil contamination showed that the PCBs concentrations varies from 0. The temporal trends of the contamination distribution with the soil depth showed contamination migration in the upper soil layers of the highly polluted site. The high level of water pollution The plant uptake of PCBs , even on the extremely contaminated site, was shown.
In turn, this research present new knowledge necessary for the development of a contaminated territory remediation strategy. Developmental disorders of the brain can be caused by PCBs ; low doses of hydroxy- PCBs disrupt thyroid hormone-dependent dendrite formation from Purkinje neurons in culture. Exposure to some environmental chemicals during the perinatal period causes developmental disorders of the brain.
Cognitive impairment and hyperactivity in infants were reported in Taiwan, known as Yu-cheng incidents caused by the accidental contamination of polychlorinated biphenyls PCBs. Together with recent experimental data, Kuroda proposes a hypothesis that spatio-temporal disruptions of developing neuronal circuits by PCB exposure can cause the comobidity of learning disorders LD , attention deficit hyperactivity disorder ADHD and autsm with the co-exposure to other environmental chemicals.
TH deficiency in the perinatal period causes cretinism children with severe cognitive and mental retardation. In primate model, Rice demonstrates that postnatal exposure to PCBs can dramatically influence later behavioral function. Epidemiological studies also indicate the possible developmental neurotoxicity of PCBs accumulated in human bodies. It is important to establish a simple, reproducible, and sensitive in vitro assay for determining the effects of PCBs and OH- PCBs on the development of the central nervous system.
Recently Iwasaki et al. We also have demonstrated TH-dependent development of Purkinje neurons in vitro using a serum-free chemically defined medium. The degree of dendritic development of Purkinje cells is TH dose-dependent and exhibits high sensitivity in the pM order. Therefore, in the present study.
Levels of polychlorinated biphenyls PCBs and three organochlorine pesticides in fish from the Aleutian Islands of Alaska. Full Text Available Persistent organic pollutants POPs, including polychlorinated biphenyls PCBs and chlorinated pesticides, have been shown to have many adverse human health effects.
These contaminants therefore may pose a risk to Alaska Natives that follow a traditional diet high in marine mammals and fish, in which POPs bioaccumulate. The highest median PCB level was found in rock sole Lepidopsetta bilineata, ppb, wet weight, while the lowest level was found in rock greenling Hexagrammos lagocephalus, ppb, wet weight. Lipid adjusted PCB values were also calculated and significant interspecies differences were found. Again, rock sole had the highest level 68, ppb, lipid weight.
Concerning the PCB congener patterns, the more highly chlorinated congeners were most common as would be expected due to their greater persistence. Among the pesticides, p, p'-DDE generally dominated, and the highest level was found in sockeye salmon Oncorhynchus nerka, 6. The methodology developed by U. For cancer health endpoints for PCBs , all species would trigger strict advisories of between two and six meals per year, depending upon species. For noncancer effects by PCBs , advisories of between seven and twenty-two meals per year were triggered.
None of the pesticides triggered consumption limits. The fish analyzed, mainly from Adak, contain significant concentrations of POPs, in particular PCBs , which raises the question whether these fish are safe to eat, particularly for sensitive populations. However when assessing any risk of the traditional diet, one must also consider the many health and cultural benefits from eating.
This study was conducted to measure the levels of 23 PCB congeners and 6 organochlorine pesticides OCPs in human milk and three food types collected from Luqiao and Pingqiao in Zhejiang Province, China. An effort was also made to explore the potential health risk for the mothers and breast-fed infants living in these two localities. Luqiao was selected as the sampling site because it is the largest place for the disassembly of obsolete transformers and electrical waste in China.
Pingqiao, located km NW of Luqiao, is not known to be a place for any electronic or electrical waste and hence was chosen as the control site. Both localities are important agricultural places in the province. The data showed that the human milk, rice, hen egg, and fish samples from Luqiao were more heavily contaminated with PCBs than those from Pingqiao, suggesting that the mothers and their breast-fed infants in Luqiao tended to receive greater exposure to PCBs than those living in Pingqiao.
The OCP levels in the two localities were found comparable, suggesting that the major source of contamination with these pesticides was from their agricultural uses. Comparison with literature data showed that the PCB levels in milk samples from Luqiao were significantly higher than those from localities in other Chinese provinces and comparable to those in developed or industrialized countries.
The whole data set 19 compounds was divided into a training set 15 compounds for model generation and a test set 4 compounds for model validation. Randomly selected from a set of models, CoMFA analysis revealed that the corresponding percentages of the variance explained by steric and electrostatic fields were The electrostatic field was determined as a primary factor governing the logKOA. These results are.
Aquatic ecological risk assessment was performed using the joint probability curve method and the Monte Carlo- based HQ hazard quotient distribution method. The combined risks of similar chemicals and the total risk of dissimilar categories of chemicals were assessed based on the principles of joint toxicity. The total risk caused by these pollutants was very high.
Due to their high persistence and potential source from land, the high risks of such pollutants are likely to last for a long period of time. Bioaccumulation of PCBs in Arctic seabirds: influence of dietary exposure and congener biotransformation. Four seabird species and their prey zooplankton or fish were collected in the Barents Sea to determine how dietary exposure, cytochrome P CYP enzyme activities and sex influenced their hepatic PCB concentrations and accumulation patterns.
Five males and five females from each seabird species little auk Alle alle , Bruennich's guillemot Uria lomvia , black guillemot Cepphus grylle and black-legged kittiwake Rissa tridactyla were analysed. The PCB pattern also differed among auks, with little auk as the most efficient biotransformer highest R PCB values of persistent congeners. Based on high R PCB values, Bruennich's guillemot poorly metabolised ortho-meta-unsubstituted congeners, whereas black guillemot poorly metabolised meta-para unsubstituted congeners.
Radiolytic removal of PCBs from isooctane and hydraulic oil solutions. Radiolysis with gamma-rays may be achieved in the absence of activation or contamination and does not result in a radiologically contaminated product. While much of the original work was done in isopropanol, recent studies have been performed in isooctane as an oil surrogate.
Use of isooctane permits radiolysis studies in a surrogate reasonably similar to oils yet one in which analytical work is considerably simplified. Results in both isopropanol and isooctane show the mechanism to be one of reductive dechlorination, probably associated with electron capture of solvated electrons by the PCBs. The electrons are generated by radiolysis of the solvent. Data is presented showing rate constants for the radiolysis of individual PCB congeners, in isooctane and the decomposition of Aroclor in hydraulic oil.
Antunes, P. Fish captured in the coastal zone and estuaries often contains enhanced residues of organochlorine compounds in their tissues, in response to environmental contamination. Residues in fish tissues may be eliminated by different pathways, but most of what is known comes from laboratory studies with species that are exposed to contaminants. In recent years, the importance of ethoxyresorufin O-deethylase EROD , one of the hepatic cytochrome P dependent monooxidase, has become widely known, and it is increasingly accepted as an indicator of exposure to common organic pollutants.
The objective of this study was to examine the levels of PCBs and DDTs in muscle and liver when individuals are exposed to clean sea water and uncontaminated food, and to evaluate whether this is a feasible option for depuration. Dioxins and PCBs in feed and food--review from European perspective. Therefore, in the EU Commission developed a strategy to reduce the presence of dioxins and PCBs in the environment and in the food chain. The legislative measures comprised maximum levels and action levels for feed and food, and a Rapid Alert System for detected incidents was introduced.
The network of the EU Reference Laboratory and National Reference Laboratories contributes to harmonization within the EU Member States and developed analytical criteria for screening and confirmatory methods for control of feed and food. After all these efforts it is of general interest to see whether these measures had an effect. The evaluation of the European Food Safety Authority EFSA based on comprehensive monitoring data of 26 European countries shows a general decrease in dietary exposure of dioxins and DL- PCBs between and , estimated to be between Toddlers and other children were the most exposed groups being at the upper end of these ranges.
Fish, meat and dairy products appeared to be the highest contributing food groups to dietary exposure. Published by Elsevier B. The evaluation of the European Food Safety Authority EFSA based on comprehensive monitoring data of 26 European countries shows a general decrease in dietary exposure of dioxins and DL- PCBs between — and —, estimated to be between Potential for phytoextraction of PCBs from contaminated soils using weeds. A comprehensive investigation of the potential of twenty-seven different species of weeds to phytoextract polychlorinated biphenyls PCBs from contaminated soil was conducted at two field sites Etobicoke and Lindsay in southern Ontario, Canada.
All species accumulated PCBs in their root and shoot tissues. Mean shoot concentrations at the two sites ranged from 0. Application of immunogold- silver staining and immunoenzymatic methods in multiple labelling of human pancreatic Langerhans islet cells. If IGSS was applied first, the black colour of silver -enhanced colloidal gold on doubly immunostained sections contrasted with the colours of most of the chromogens used generally in the 2 immunoenzymatic methods.
If IGSS was followed by immunoalkaline phosphatase and immunoperoxidase techniques in optional sequence, 3 different hormone-containing cell types could be stained simultaneously without non-specific cross-reactions. IGSS and immunoalkaline phosphatase methods, together with 2 kinds of non-cross-reacting immunoperoxidase systems, permitted the detection of 4 distinct antigens on the same tissue section.
Multiple immunohistochemical labelling of the endocrine pancreas provides an opportunity for the correct and rapid analysis of the topographic and morphometric relationships between different hormone-producing cell populations under both normal and pathological conditions. IGSS is of great potential for the simultaneous immunolabelling of antigens situated within separate cells.
Characterisation of the nucleolar organising regions during the cell cycle in two varieties of Petunia hybrida as visualised by fluorescence in situ hybridisation and silver staining. The cell cycle-dependent spatial position, morphology and activity of the four nucleolar organising regions NORs of the Petunia hybrida cultivar Mitchell and the inbred line V26 have been analysed.
Application of the silver staining technique and fluorescence in situ hybridisation on fixed root-tip material revealed that these interspecific hybrids possess four NORs of which only those of chromosome 2 are active during interphase, which implies that the NOR activity is not of parental origin. However, at the end of mitosis, activity of all NOR regions could be detected, suggesting that the high demand for ribosomes at this stage of the cell cycle requires temporal activity of all NORs.
Using actin DNA probes as markers in fluorescence in situ hybridisation experiments enabled the identification of the individual petunia chromosomes. Quantitating silver-stained neurodegeneration: the neurotoxicity of trimethlytin TMT in aged rats. This report describes the development of a histoanalytical procedure to measure the degree of neurodegeneration produced by the organometal toxicant trimethyltin TMT. Based on a previous, non-quantitated experiment we hypothesized that the same dose of TMT would produce greater damage in animals of increasing age.
Male rats aged 6, 12, 18, or 24 months at the time of dosing were given either 4. One month after dosing, rats were perfused and their brains removed and processed to selectively silver -impregnate degenerating cell bodies as well as axon terminals and dendrites.
Neurodegeneration was most prominent in the hippocampi especially CA1 stratum radiatum of TMT-treated rats, but not in the controls. Computer-assisted counting of the silver grains marking damage indicated greater neurotoxicity from the same dose of TMT when given to the older animals.
The month-old TMT-treated rats had significantly increased grain densities compared to their controls P silver grains marking neurodegeneration should be adaptable to a wide range of histologically-based neurotoxicology investigations. A comparison of sperm morphology and silver nitrate staining characteristics in the domestic ferret and the black-footed ferret. Ejaculated sperm from the domestic ferret Mustela putorius furo and the black-footed ferret Mustela nigripes were compared for differences in morphological abnormalities and argentophilic protein distribution.
Thawed domestic ferret sperm was also compared to fresh sperm to determine whether there were any effects on cell morphology due to cryopreservation. There were statistically significant differences between the two species of ferret in two of the categories scored.
The domestic ferret had a higher frequency of cells that were bent in the midpiece and in the principal piece, and a higher frequency of headless and tailless cells when compared to the black-footed ferret. There were no statistically significant differences in cell morphology between the fresh and cryopreserved ejaculates of the domestic ferret employing a standard egg yolk cryoextender.
Silver nitrate staining distribution was different between the two species in both the head and tail region. Pleural fluid Gram stain. Gram stain of pleural fluid A laboratory specialist uses a microscope to The Gram stain can help identify the bacteria that might The sophisticated colors of medieval glasses arise from their transition metal TM impurities and capture information about ancient glassmaking techniques.
Beyond the glass chemical composition, the TM redox is also a key factor in the glass color, but its quantification without any sampling is a challenge. These particular glass pieces must have been produced as a single shot, which guarantees that the chemical variations reflect the recipe in use in a specific medieval workshop.
The quantitative elemental mappings demonstrate that the colored glass parts are derived from the same base glass, to which TMs were deliberately added. Furthermore, the derivation of the quantitative redox state of each TM in each color shows that the contents of Fe, Cu, and Mn were adjusted to ensure a reducing glass matrix in the red stripe or a metastable overoxidized glass in the purple stripe.
We infer that the agility of the medieval glassmaker allowed him to master the redox kinetics in the glass by rapid shaping and cooling to obtain a snapshot of the thermodynamically unstable glass colors. Parametric separation of carbon nanotubes, especially based on their length is a challenge for a number of nano-tech researchers. We demonstrate a method to combine bio-conjugation, SDS-PAGE, and silver staining in order to separate carbon nanotubes on the basis of length.
Egg-white lysozyme, conjugated covalently onto the single-walled carbon nanotubes surfaces using carbodiimide method. The proposed conjugation of a biomolecule onto the carbon nanotubes surfaces is a novel idea and a significant step forward for creating an indicator for length-based carbon nanotubes separation. This high precision, inexpensive, rapid and simple separation method obviates the need for centrifugation, additional chemical analyses, and expensive spectroscopic techniques such as Raman spectroscopy to visualize carbon nanotube bands.
In this method, we measured the length of nanotubes using different image analysis techniques which is based on a simplified hydrodynamic model. The method has high precision and resolution and is effective in separating the nanotubes by length which would be a valuable quality control tool for the manufacture of carbon nanotubes of specific lengths in bulk quantities.
To this end, we were also able to measure the carbon nanotubes of different length, produced from different sonication time intervals. Immunocytolocalization of extensin in developing soybean seed coats by immunogold- silver staining and by tissue printing on nitrocellulose paper. In soybean seed coats the accumulation of the hydroxyproline-rich glycoprotein extensin is regulated in a developmental and tissue- specific manner.
The time course of appearance of extensin during seed development was studied by Western blot analysis and by immunogold- silver localization. Using these techniques extensin was first detected at d after anthesis, increasing during development to high levels at 24 d after anthesis. Immunogold- silver localization of extensin in the seed coat showed marked deposition of the glycoprotein in the walls of palisade epidermal cells and hourglass cells.
The immunolocalization of extensin in developing soybean seeds was also made by a new technique--tissue printing on nitrocellulose paper. It was found that extensin is primarily localized in the seed coat, hilum, and vascular elements of the seed. The purpose of structural assessments in neurotoxicology is to provide a convincing picture of the location and extent of damage to the nervous system.
A developed Christmas-tree derived immunosensor based on a gold label silver stain GLSS technique was fabricated for a highly sensitive analysis of Vibrio parahaemolyticu VP. In this strategy, captured VP antibody cAb was immobilized on a solid substrate; then, the VPs were sequentially tagged with a signal probe by incubating the assay with a detection VP antibody dAb conjugated gold nanoparticles AuNPs -labeled graphite-like carbon nitride g-C 3 N 4.
Finally, the attached signal probe could harvest a visible signal by the silver meal deposition, and then followed by homebrew Matlab 6. In addition, the overall design of the biosensor was established in abundant AuNPs and g-C 3 N 4 with a two-dimensional structure, affording a bulb-decorated Christmas-tree model.
Moreover, with the optimized conditions, the detection limit of the as-proposed biosensor is as low as 10 2 CFU Colony-Forming Units mL -1 , exhibiting an increase of two orders of magnitude compared with the traditional immune-gold method. Additionally, the developed visible immunosensor was also successfully applied to the analysis of complicated samples. Immunofluorescent staining reveals hypermethylation of microchromosomes in the central bearded dragon, Pogona vitticeps. Studies of model organisms have demonstrated that DNA cytosine methylation and histone modifications are key regulators of gene expression in biological processes.
Comparatively little is known about the presence and distribution of epigenetic marks in non-model amniotes such as non-avian reptiles whose genomes are typically packaged into chromosomes of distinct size classes. Studies of chicken karyotypes have associated the gene-richness and high GC content of microchromosomes with a distinct epigenetic landscape. To determine whether this is likely to be a common feature of amniote microchromosomes, we have analysed the distribution of epigenetic marks using immunofluorescence on metaphase chromosomes of the central bearded dragon Pogona vitticeps.
This study is the first to study the distribution of epigenetic marks on non-avian reptile chromosomes. We observed an enrichment of DNA cytosine methylation, active modifications H3K4me2 and H3K4me3, as well as the repressive mark H3K27me3 in telomeric regions on macro and microchromosomes. Microchromosomes were hypermethylated compared to macrochromosomes, as they are in chicken.
However, differences between macro- and microchromosomes for histone modifications associated with actively transcribed or repressed DNA were either less distinct or not detectable. Hypermethylation of microchromosomes compared to macrochromosomes is a shared feature between P.
The lack of the clear distinction between macro- and microchromosome staining patterns for active and repressive histone modifications makes it difficult to determine at this stage whether microchrosome hypermethylation is correlated with greater gene density as it is in aves, or associated with the greater GC content of P.
New aspects of membrane dynamics of Amoeba proteus contractile vacuole revealed by vital staining with FM The contractile vacuole CV cycle of Amoeba proteus has been studied by phase contrast and electron microscopy. However, the understanding of membrane dynamics in this cycle is still poor.
In this study, we used live imaging by fluorescence microscopy to obtain new insights. We succeeded in staining the CV with a styryl dye, FM N- 3-triethylammoniumpropyl 6- 4- diethylamino phenyl hexatrienyl pyridinium dibromide , and obtained the following results. This indicates that transfer of plasma membrane to the CV does not occur. In particular, the fluorescent CV membrane was maintained as an aggregate just after contraction and the vacuole re-formed from the aggregate.
Staining was maintained during continued contraction cycles. We conclude that the CV membrane is maintained during the CV cycle. Quantum dot-based local field imaging reveals plasmon-based interferometric logic in silver nanowire networks. We show that the local electric field distribution of propagating plasmons along silver nanowires can be imaged by coating the nanowires with a layer of quantum dots, held off the surface of the nanowire by a nanoscale dielectric spacer layer.
In simple networks of silver nanowires with two optical inputs, control of the optical polarization and phase of the input fields directs the guided waves to a specific nanowire output. The QD-luminescent images of these structures reveal that a complete family of phase-dependent, interferometric logic functions can be performed on these simple networks.
These results show the potential for plasmonic waveguides to support compact interferometric logic operations. Aquatic environments are heavily impacted by human activities including climate warming and the introduction of xenobiotics.
Due to the application of silver nanoparticles as bactericidal agent the introduction of silver into the environment strongly has increased during the past years. Silver ions affect the primary metabolism of algae, in particular photosynthesis. Mixotrophic algae are an interesting test case as they do not exclusively rely on photosynthesis which may attenuate the harmful effect of silver. In order to study the effect of silver ions on mixotrophs, cultures of the chrysophyte Poterioochromonas malhamensis were treated in a replicate design in light and darkness with silver nitrate at a sub-lethal concentration.
At five time points samples were taken for the identification and quantitation of proteins by mass spectrometry. In our analysis, relative quantitative protein mass spectrometry has shown to be a useful tool for functional analyses in conjunction with transcriptome reference sequences. A total of 3, proteins in 63 samples were identified and quantified, mapping to 4, transcripts of the sequenced and assembled transcriptome.
Among them, and proteins performing various cellular functions were differentially expressed after eight days in light versus darkness and after three days of silver treatment, respectively. Specifically pathways of the energy and primary carbon metabolism were differentially affected by light and the utilization of expensive reactions hints to an energy surplus of P.
The excess energy is not invested in growth, but in the synthesis of storage metabolites. The effects of silver were less explicit, observable especially in the dark treatments where the light effect could not mask coinciding but weaker effects of silver. Photosynthesis, particularly the light harvesting complexes, and several sulphur containing enzymes were affected presumably due to a direct.
Gram staining. Named after Hans Christian Gram who developed the method in , the Gram stain allows one to distinguish between Gram-positive and Gram-negative bacteria on the basis of differential staining with a crystal violet-iodine complex and a safranin counterstain.
The cell walls of Gram-positive organisms retain this complex after treatment with alcohol and appear purple, whereas gram-negative organisms decolorize following such treatment and appear pink. The method described here is useful for assessing bacterial contamination of tissue culture samples or for examining the Gram stain status and morphological features of bacteria isolated from mixed or isolated bacterial cultures.
Gram Stain. Dynamic protein coronas revealed as a modulator of silver nanoparticle sulphidation in vitro. Proteins adsorbing at nanoparticles have been proposed as critical toxicity mediators and are included in ongoing efforts to develop predictive tools for safety assessment. Strongly attached proteins can be isolated, identified and correlated to changes in nanoparticle state, cellular association or toxicity.
Weakly attached, rapidly exchanging proteins are also present at nanoparticles, but are difficult to isolate and have hardly been examined. Here we study rapidly exchanging proteins and show for the first time that they have a strong modulatory effect on the biotransformation of silver nanoparticles.
Released silver ions, known for their role in particle toxicity, are found to be trapped as silver sulphide nanocrystals within the protein corona at silver nanoparticles in serum-containing cell culture media. The strongly attached corona acts as a site for sulphidation, while the weakly attached proteins reduce nanocrystal formation in a serum-concentration-dependent manner. Sulphidation results in decreased toxicity of Ag NPs. Stable RNA markers for identification of blood and saliva stains revealed from whole genome expression analysis of time-wise degraded samples.
Human body fluids such as blood and saliva represent the most common source of biological material found at a crime scene. Reliable tissue identification in forensic science can reveal significant insights into crime scene reconstruction and can thus contribute toward solving crimes. Limitations of existing presumptive tests for body fluid identification in forensics, which are usually based on chemoluminescence or protein analysis, are expected to be overcome by RNA-based methods, provided that stable RNA markers with tissue-specific expression patterns are available.
To generate sets of stable RNA markers for reliable identification of blood and saliva stains we 1 performed whole-genome gene expression analyses on a series of time-wise degraded blood and saliva stain samples using the Affymetrix U plus2 GeneChip, 2 consulted expression databases to obtain additional information on tissue specificity, and 3 confirmed expression patterns of the most promising candidate genes by quantitative real-time polymerase chain reaction including additional forensically relevant tissues such as semen and vaginal secretion.
We propose the use of these 14 stable mRNA markers for identification of blood and saliva stains in future forensic practice. Electronic supplementary material The online version of this article doi Due to their well-known antifungal activity, the intentional use of Ag nanoparticle NPs as sustainable nano-fungicides is expected to increase in agriculture.
However, the impacts of AgNPs on plants must be critically evaluated to guarantee their safe use in food production. Gas chromatography-mass spectrometry GC-MS based non-target metabolomics enabled the identification and quantification of metabolites in cucumber leaves.
Multivariate analysis revealed that all the treatments significantly altered the metabolite profile. Exposure to AgNPs resulted in metabolic reprogramming, including activation of antioxidant defense systems up-regulation of phenolic compounds and down-regulation of photosynthesis up-regulation of phytol.
Although Ag ions induced some of the same metabolic changes, alterations in the levels of carbazole, indoleactate, raffinose, adenosine, lactamide, erythrose, and p-benzoquinone were AgNPs-specific. The results of this study offer new insight into the molecular mechanisms by which cucumber responds to AgNPs exposure and provide important information to support the sustainable use of AgNPs in agriculture.
Genetic evidence for gonochoristic reproduction in gynogenetic silver crucian carp Carassius auratus gibelio bloch as revealed by RAPD assays. Sex evolution has been a debating focus in evolutionary genetics.
In lower vertebrates of reptiles, amphibians, and fish, a species or a bioform reproduces either sexually or asexually but never both. A few species were found to consist of all females in fish. These all-female species can propagate by asexual reproduction modes, such as gynogenesis and hybridogenesis.
However, the coexistence of sexuality and asexuality in a single species was recently noted only in a cyprinid fish silver crucian carp, Carassius auratus gibelio. This fish had been demonstrated to be capable of gynogenesis stimulated by sperm from other related species. Surprisingly, natural populations of this fish consist of a minor but significant portion approx. As different clones with specific phenotypic and genetic characteristics have been found, and RAPD markers specific to each clone have recently been identified, this fish offers many advantages for analyzing whether or not genetic recombination occurs between different clones.
In this study, artificial propagation was performed in clone F and clone D. Ovulated eggs from clone F were divided into two parts and respectively inseminated with sperm from a clone D male and from a red common carp Cyprinus carpio male. The control clone D individuals were selected from gynogenetic offspring of clone D activated by sperm of red common carp.
The phenotype and sex ratio in the experimental groups were also observed. Using RAPD molecular markers, which allow for reliable discrimination and genetic analysis of different clones, we have revealed direct molecular evidence for gonochoristic reproduction in the gynogenetic silver crucian carp and confirmed a previous hypothesis that the silver crucian carp might reproduce both gynogenetically and gonochoristically. Therefore, we conclude that the silver crucian carp possesses two reproductive modes, i.
The response mechanism of two. Diagnostic SNPs reveal widespread introgressive hybridization between introduced bighead and silver carp in the Mississippi River Basin. Hybridization among conspecifics in native and introduced habitats has important implications for biological invasions in new ecosystems. Bighead Hypophthalmichthys nobilis and silver carp H. Following their introduction to North America, however, introgressant hybrids have been reported throughout their expanded range within the Mississippi River Basin MRB.
The extent of introgression, both spatially and generationally, is largely unknown. Therefore, we examined mixed-species populations from across the MRB to characterize the extent of interspecific gene flow. We assayed individuals from nine locations with a suite of species-diagnostic SNPs 57 nuclear and one mitochondrial.
Moreover, the composition of hybrid genotypes varied among locations and represented complex hybrid swarms with multiple generations of gene flow. Introgressive hybrids were identified from all locations, were bidirectional and followed a bimodal distribution consisting primarily of parental or parental-like genotypes and phenotypes.
All described hybrid categories were present among individuals from to , with parents and later-generation backcrosses representing the largest proportion of individuals among years. The application of this suite of diagnostic markers and the spatial coverage permits a deeper examination of the complexity in hybrid swarms between two invasive, introduced species.
Chemical studies have been carried out on the interaction of DNA with uranyl salts. The effect of variations in pH, salt concentration, and structural integrity of the DNA on the stoichiometry of the salt-substrate complex have been investigated. At pH 3.
At low pH's about 2. Destruction of the structural integrity of the DNA by heating in HCHO solutions leads to a similar drop in the amount of metal ion bound. Raising the pH above 3. This additional binding has a lower association constant. Under similar conditions DNA binds about seven times more uranyl ion than bovine serum albumin, indicating useful selectivity in staining for electron microscopy.
Silver nanoparticles AgNPs , like almost all nanoparticles, are potentially toxic beyond a certain concentration because the survival of the organism is compromised due to scores of pathophysiological abnormalities past that concentration. However, the mechanism of AgNP toxicity remains undetermined. Instead of applying a toxic dose, we attempted to monitor the effects of AgNPs at a nonlethal concentration on wild type Drosophila melanogaster by exposing them throughout their development.
Additionally, fertility and vertical movement ability were compromised due to AgNP feeding. Biochemical analysis suggests that the activity of copper dependent enzymes, namely tyrosinase and Cu-Zn superoxide dismutase, are decreased significantly following the consumption of AgNPs, despite the constant level of copper present in the tissue.
Consequently, we propose a mechanism whereby consumption of excess AgNPs in association with membrane bound copper transporter proteins cause sequestration of copper, thus creating a condition that resembles copper starvation. This model also explains the cuticular demelanization effect resulting from AgNP since tyrosinase activity is essential for melanin biosynthesis. Finally, we claim that Drosophila, an established genetic model system, can be well utilized for further understanding of the biological effects of nanoparticles.
Cysticidal drug treatment of viable Taenia solium brain parenchymal cysts leads to an acute pericystic host inflammatory response and blood brain barrier breakdown BBB , commonly resulting in seizures. Naturally infected pigs, untreated or treated one time with praziquantel were sacrificed at 48 hr and hr following the injection of Evans blue EB to assess the effect of treatment on larval parasites and surrounding tissue. Examination of harvested non encapsulated muscle cysts unexpectedly revealed one or more small, focal round region s of Evans blue dye infiltration REBI on the surface of otherwise non dye- stained muscle cysts.
Histopathological analysis of REBI revealed focal areas of eosinophil-rich inflammatory infiltrates that migrated from the capsule into the tegument and internal structures of the parasite. In addition some encapsulated brain cysts, in which the presence of REBI could not be directly assessed, showed histopathology identical to that of the REBI.
Muscle cysts with REBI were more frequent in pigs that had received praziquantel 6. Similar results were found in the brain, where REBI likely represent early damaging host responses to T. These findings suggest new avenues for immunomodulation to reduce inflammatory side effects of anthelmintic therapy.
Distribution of silver in rats following 28 days of repeated oral exposure to silver nanoparticles or silver acetate. Background The study investigated the distribution of silver after 28 days repeated oral administration of silver nanoparticles AgNPs and silver acetate AgAc to rats.
Oral administration is a relevant route of exposure because of the use of silver nanoparticles in products related to food and food contact materials. The AgNPs remained stable throughout the duration of the day oral toxicity study in rats.
However the absolute silver concentrations in tissues were lower following oral exposure to AgNPs. This was in agreement with an indication of a higher fecal excretion following administration of AgNPs. Besides the intestinal system, the largest silver concentrations were detected in the liver and kidneys. Silver was also found in the lungs and brain. Autometallographic AMG staining revealed a similar cellular localization of silver in ileum, liver, and kidney tissue in rats exposed to AgNPs or AgAc.
Using transmission electron microscopy TEM , nanosized granules were detected in the ileum of animals exposed to AgNPs or AgAc and were mainly located in the basal lamina of the ileal epithelium and in lysosomes of macrophages within the lamina propria. Using energy dispersive x-ray spectroscopy it was shown that the granules in lysosomes consisted of silver , selenium, and sulfur for both AgNP and AgAc exposed rats.
The diameter of the deposited granules was in the same size range as that of the administered AgNPs. No silver granules were detected by TEM in the liver. Conclusions The results of the present study demonstrate that the organ distribution of silver was similar when AgNPs or AgAc were administered orally to rats. The presence of silver granules containing.
Frequency of satellite association of human chromosomes is correlated with amount of Ag- staining of the nucleolus organizer region. Methaphase chromosomes from karyotypically normal adult humans three males, six females and one male with a 13p - chromosome were stained by quinacrine and then by the Ag-AS silver staining method to reveal nucleolus organizer regions NORs. Each person had a characteristic number of Ag- stained chromosomes per cell, always fewer than Determination of the mean Ag-size of each chromosome showed that each of the 10 individuals had a unique distribution of Ag- stain.
Within each individual, there was some variation from cell to cell in the number of acrocentric chromosomes that were Ag- stained ; this was not random, and the same chromosomes those that had at most a small amount of Ag- stain tended to be unstained in every cell. Satellite associations were scored on the same cells. Regression analysis of the 50 of a total of acrocentric chromosomes which could be individually identified by quinacrine markers showed that the frequency with which a chromosome was involved in satellite association was strongly correlated with the amount of Ag- stained material in the NOR.
Images Fig. Pericardial fluid Gram stain. Pericardial fluid Gram stain is a method of staining a sample of fluid taken from the pericardium. This is the sac surrounding Differential staining of bacteria: gram stain. In , Hans Christian Gram, a Danish doctor, developed a differential staining technique that is still the cornerstone of bacterial identification and taxonomic division.
This multistep, sequential staining protocol separates bacteria into four groups based on cell morphology and cell wall structure: Gram-positive cocci, Gram-negative cocci, Gram-positive rods, and Gram-negative rods. The Gram stain is useful for assessing bacterial contamination of tissue culture samples or for examining the Gram stain status and morphological features of bacteria isolated from mixed or isolated bacterial cultures. Aureobasidium pullulans morphology: two adapted polysaccharide stains.
Morphological stages of Aureobasidium pullulans were investigated utilizing different media ingredients and were visualized by bright-field microscopy. A polysaccharide stain was developed to stain chlamydospores, cell walls, hyphae, and conidia, since current staining techniques do not reveal subcellular details to identify fungi, especially those that exhibit polysaccharide secretions. We conclude that some patients with ATL possess functional tumour-specific CTLs which could be exploited to contribute to control of the disease.
The history of histology indicates that there have been significant changes in the techniques used for histological staining through chemical, molecular biology assays and immunological techniques, collectively referred to as histochemistry. Early histologists used the readily available chemicals to prepare tissues for microscopic studies; these laboratory chemicals were potassium dichromate, alcohol and the mercuric chloride to harden cellular tissues.
Staining techniques used were carmine, silver nitrate, Giemsa, Trichrome Stains , Gram Stain and Hematoxylin among others. The purpose of this research was to assess past and current literature reviews, as well as case studies, with the aim of informing ways in which histological stains have been improved in the modern age. Results from the literature review has indicated that there has been an improvement in histopathology and histotechnology in stains used. There has been a rising need for efficient, accurate and less complex staining procedures.
Many stain procedures are still in use today, and many others have been replaced with new immunostaining, molecular, non-culture and other advanced staining techniques. Some staining methods have been abandoned because the chemicals required have been medically proven to be toxic.
The case studies indicated that in modern histology a combination of different stain techniques are used to enhance the effectiveness of the staining process. Currently, improved histological stains , have been modified and combined with other stains to improve their effectiveness. Silver diagnosis in neuropathology: principles, practice and revised interpretation. Silver-staining methods are helpful for histological identification of pathological deposits.
In spite of some ambiguities regarding their mechanism and interpretation, they are widely used for histopathological diagnosis. In this review, four major silver-staining methods, modified Bielschowsky, Bodian, Gallyas GAL and Campbell—Switzer CS methods, are outlined with respect to their principles, basic protocols and interpretations, thereby providing neuropathologists, technicians and neuroscientists with a common basis for comparing findings and identifying the issues that still need to be clarified.
Thus, they seek to explain the differences among the methods by pointing to their different sensitivities in detecting lesions quantitative difference. Comparative studies, however, have demonstrated that argyrophilia is heterogeneous and dependent not only on the method but also on the lesion qualitative difference.
Each staining method has its own lesion-dependent specificity and, within this specificity, its own sensitivity. Although no molecular explanations, other than these empiric correlations, are currently available, these distinctive features, especially when combined with immunohistochemistry, are.
Interaction of gold and silver nanoparticles with human plasma: Analysis of protein corona reveals specific binding patterns. Determining how nanomaterials interact with plasma will assist in understanding their effects on the biological system. This work presents a systematic study of the protein corona formed from human plasma on 20nm silver and gold nanoparticles with three different surface modifications, including positive and negative surface charges.
The results show that all nanoparticles, even those with positive surface modifications, acquire negative charges after interacting with plasma. Approximately proteins are identified on the coronas, while 99 are commonly found on each nanomaterial. Remarkably, the surface charge and core of the nanoparticles, as well as the isoelectric point of the plasma proteins, are found to play significant roles in determining the nanoparticle coronas.
Fibrinogen, which presents in the plasma but not in the serum, preferably binds to negatively charged gold nanoparticles. These observations demonstrate the specific plasma protein binding pattern of silver and gold nanoparticles, as well as the importance of the surface charge and core in determining the protein corona compositions. The potential downstream biological impacts of the corona proteins were also investigated.
All rights reserved. Revealing text in a complexly rolled silver scroll from Jerash with computed tomography and advanced imaging software. Throughout Antiquity magical amulets written on papyri, lead and silver were used for apotropaic reasons. While papyri often can be unrolled and deciphered, metal scrolls, usually very thin and tightly rolled up, cannot easily be unrolled without damaging the metal.
This leaves us with unreadable results due to the damage done or with the decision not to unroll the scroll. The texts vary greatly and tell us about the cultural environment and local as well as individual practices at a variety of locations across the Mediterranean.
Here we present the methodology and the results of the digital unfolding of a silver sheet from Jerash in Jordan from the mid-8th century CE. The scroll was inscribed with 17 lines in presumed pseudo-Arabic as well as some magical signs.
The successful unfolding shows that it is possible to digitally unfold complexly folded scrolls, but that it requires a combination of the know-how of the software and linguistic knowledge. Differential staining of bacteria: acid fast stain. Acid-fastness is an uncommon characteristic shared by the genera Mycobacterium Section 10A and Nocardia. Because of this feature, this stain is extremely helpful in identification of these bacteria.
Although Gram positive, acid-fast bacteria do not take the crystal violet into the wall well, appearing very light purple rather than the deep purple of normal Gram-positive bacteria. Port-wine stain. Laser therapy is most successful in removing port-wine stains. It is the only method that can destroy the tiny blood vessels in the skin without causing much damage to the skin.
The exact type Iron Stain on Wood. Oak, redwood, cypress, and cedar are particularly prone to iron stain because these woods contain large amounts of tannin-like extractives. The discoloration is caused by a chemical reaction between extractives in the wood and iron in steel products, such as nails, screws, and Candida, fluorescent stain image.
Candida is a yeast fungus that causes mild disease, but in immunocompromised individuals it may cause life-threatening illness. Image courtesy of the Centers for Port-Wine Stains. Port-wine stains can also develop grape-like growths of small blood vessels called vascular It's also important, emotionally, for kids to Sputum stain for mycobacteria.
Alternative Names Acid fast bacilli Sputum test References Hopewell Efficacy test of a toothpaste in reducing extrinsic dental stain. Agustanti, A. This clinical trial compared the external dental stain reduction achieved by tested toothpaste versus placebo in adult patients. In this double-blind, parallel, randomised clinical trial, 45 female volunteers with a mean age of 20 years old were included.
All study subjects front teeth were topically applicated with Silver Diamine Fluoride SDF to create external dental stains. Toothpastes were used for two days to analyse the effects of removing external stains on the labial surfaces of all anterior teeth. The analysis showed statistically significant efficacy of the tested toothpaste in reducing external dental stain caused by SDF, comparing to the placebo toothpaste, after one and two days of usage.
The tested toothpaste was effective in reducing dental stain. Gram stain of tissue biopsy. Gram stain of tissue biopsy test involves using crystal violet stain to test a sample of tissue taken from a biopsy. The Gram stain method can Stained -Glass Pastels. The author has always liked the look of stained -glass windows.
Usually the designs are simplified and the shapes are easier for younger students to draw. This technique seemed to be the perfect place for her fifth-graders to try their hand at color mixing. The smaller spaces and simple shapes were just what she needed for this group. Her students…. Both adults and children alike marvel at the grand vivid stained -glass windows created by American artist Louis Comfort Tiffany.
Today he is commonly recognized as one of America's most influential designers and artists throughout the last nineteenth and early twentieth century. In the lesson described in this article, students created their own….
Protein Stains to Detect Antigen on Membranes. Electroblotting drives protein molecules from a polyacrylamide or less commonly, of an agarose gel to the surface of a binding membrane, thereby facilitating an increased availability of the sites with affinity for both general and specific protein reagents.
The analysis of these complex protein mixtures is achieved by the detection of specific protein bands on a membrane, which in turn is made possible by the visualization of protein bands either by chemical staining or by reaction with an antibody of a conjugated ligand. Chemical methods employ staining with organic dyes, metal chelates, autoradiography, fluorescent dyes, complexing with silver , or prelabeling with fluorophores. All of these methods have differing sensitivities and quantitative determinations vary significantly.
This review will describe the various protein staining methods applied to membranes after western blotting. Protein stains to detect antigen on membranes. This review will describe the various protein staining methods applied to membranes after electrophoresis.
Detection is often synonymous to staining , i. Antibacterial activity and toxicity of silver - nanosilver versus ionic silver. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect.
Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.
Danyushevsky, V. It is shown that the introduction of Ag to Ni catalysts leads to an increase in the olefin yield. The role of metal hydrides formed during the reaction is extensively discussed. Modified Field's staining --a rapid stain for Trichomonas vaginalis. Trichomonas vaginalis, a flagellate protozoan parasite commonly found in the human genitourinary tract, is transmitted primarily by sexual intercourse.
Diagnosis is usually by in vitro culture method and staining with Giemsa stain. There are laboratories that use Gram stain as well. Three smears from every sediment of spun cultures of all 4 isolates were stained , respectively, with each of the stains. We showed that MF staining , apart from being a rapid stain 20 s , confers sharper staining contrast, which differentiates the nucleus and the cytoplasm of the organism when compared to Giemsa and Gram staining especially on parasites from spiked urine samples.
The alternative staining procedure offers in a diagnostic setting a rapid stain that can easily visualize the parasite with sharp contrasting characteristics between organelles especially the nucleus and cytoplasm. Vacuoles are more clearly visible in parasites stained with MF than when stained with Giemsa. Swasey, Steven M. These findings are promising for DNA nanotechnology and metal-ion based biomedical science.
Recognition of Pneumocystis carinii by gram stain in impression smears of lung tissue. The cysts appeared as 5- to 7-microns unstained spheres, each containing six to eight intracystic gram-negative bodies sporozoites. Although the Gram stain does not appear to be as sensitive as more traditional staining techniques for the detection of P.
Length of stain dosimeter. Payload customers for the Space Shuttle have recently expressed concerns about the possibility of their payloads at an adjacent pad being contaminated by plume effluents from a shuttle at an active pad as they await launch on an inactive pad. As part of a study to satisfy such concerns a ring of inexpensive dosimeters was deployed around the active pad at the inter-pad distance.
However, following a launch, dosimeters cannot be read for several hours after the exposure. As a consequence factors such as different substrates, solvent systems, and possible volatilization of HCl from the badges were studied. This observation led to the length of stain LOS dosimeters of this invention. Commercial passive LOS dosimeters are sensitive only to the extent of being capable of sensing 2 ppm to 20 ppm if the exposure is 8 hours. To map and quantitate the HCl generated by Shuttle launches, and in the atmosphere within a radius of 1.
A passive length of stain dosimeter has been developed having a sensitivity rendering it capable of detecting a gas in a concentration as low as 2 ppm on an exposure of five minutes. An indirect method for quantitation of cellular zinc content of Timm- stained cerebellar samples by energy dispersive X-ray microanalysis.
The absolute concentration of zinc in the Purkinje cells of the rat cerebellum was determined by means of energy dispersive X-ray microanalysis EDAX. Gelatine blocks with known zinc concentrations were stained by Timm's sulphide- silver method, and their silver concentrations were measured by EDAX. A linear correlation was found between the zinc and silver concentrations and this linear function was used as a quantitative calibration for evaluation of sulphide- silver staining , after perfusion with sodium-sulphide solution, fixation with glutaraldehyde, cryostat sectioning and staining of cerebellar samples in Timm's reagent.
Silver Nanoparticles. Khaydarov, R. The bactericidal effect of silver nanoparticles obtained by a novel electrochemical method on Escherichia coli, Staphylococcus aureus, Aspergillus niger and Penicillium phoeniceum cultures has been studied. The paper also provides a review of scientific literature with regard to recent developments in the field of toxicity of silver nanoparticles and its effect on environment and human health.
Paraffin-embedded sections from human tissues with fungi or organisms classified with fungi were studied by light microscopy LM , scanning electron microscopy SEM , and the backscatter electron imaging BEI mode of the SEM. The fungal organisms selected for study were those familiar to the pathologist on the basis of their appearance in paraffin-embedded material stained with the Gomori-Grocott Chromic Acid Methenamine Silver Stain GMS. This silver staining technique accentuated the wall of fungal organisms, in the backscatter mode.
Depending on the fungal organism and type of silver stain employed, the GMS seemed the preferable stain. BEI may also be used in conjunction with LM stain for microorganisms to establish their presence. Ghost mycobacteria on Gram stain. The Gram stain is a key tool in diagnostic microbiology. Its usefulness with respect to mycobacteria is undefined. The neutrality of mycobacteria other than Mycobacterium tuberculosis on Gram staining of various clinical specimens is described.
Genomic and transcriptomic comparison of allergen and silver nanoparticle-induced mast cell degranulation reveals novel non-immunoglobulin E mediated mechanisms. Mast cells represent a crucial cell type in host defense; however, maladaptive responses are contributing factors in the pathogenesis of allergic diseases. Previous work in our laboratory has shown that exposure to silver nanoparticles AgNPs results in mast cell degranulation via a non-immunoglobulin E IgE mechanism. Utilizing strain-dependent mast cell degranulation, an association mapping study identified 3 chromosomal regions that were significantly associated with mast cell degranulation by AgNP and one non-overlapping region associated with DNP-mediated degranulation.
Two of the AgNP-associated regions correspond to genes previously reported to be associated with allergic disorders Trac2 on chromosome 1 and Traf6 on chromosome 2 and an uncharacterized gene identified on chromosome 1 Famb. In conjunction, RNA-sequencing performed on mast cells from the high and low responder strains revealed and 34 differentially expressed genes that were unique to DNP and AgNP exposures, respectively.
Select candidate genes include Ptger4, a gene encoding a G-protein coupled receptor in addition to a multifunctional adaptor protein, Txnip, that may be driving mast cell degranulation by AgNP. Taken together, we identified novel genes that have not been previously shown to play a role in nanoparticle-mediated mast cell activation.
With further functional evaluation in the future, these genes may be potential therapeutic targets in the treatment of non-IgE mediated mast cell-linked disorders. Summary The relationship between integrin expression and function in pathologies is often contentious as comparisons between human pathological expression and expression in cell lines is difficult.
Western blotting of proteins is customarily performed following their separation on polyacrylamide gels, either prior to staining 1 or, as recently reported, following staining 2. We describe here Western blotting with stained gels, which had been dried and some of which had been stored for years. This procedure permits immunological analysis of proteins, to which antisera may have become available only later, or where the application of newly developed sensitive detection methods is desired.
Once rehydration of the gels is achieved, proteins can be-transferred to blotting membranes by any appropriate protocol. Proteins stained with Coomassie Blue have to be detected with a non-chromogenic method, such as the film-based enhanced chemiluminescence ECL 2 procedure 3. Silver stained proteins, which transfer in the colorless form, may be visualized by any detection method, although, because of the usually very low amounts of proteins, detection by ECL is preferable.
Blotting of stained proteins from rehydrated gels is as rapid and as quantitative as from freshly prepared gels, in contrast to blotting from wet stained gels, which requires extensive washing and results in low transfer efficiency 2.
Together with a photographic record of the gel pattern, unambiguous identification of immunoreactive proteins from complex mixtures is possible. Some further applications of this work are discussed. First report on C-banding, fluorochrome staining and NOR location in holocentric chromosomes of Elasmolomus Aphanus sordidus Fabricius, Heteroptera, Rhyparochromidae.
Abstract In spite of various cytogenetic works on suborder Heteroptera, the chromosome organization, function and its evolution in this group is far from being fully understood. Cytologically, the family Rhyparochromidae constitutes a heterogeneous group differing in chromosome numbers. This family possesses XY sex mechanism in the majority of the species with few exceptions. In the present work, multiple banding techniques viz. One pair of the autosomes was large while three others were of almost equal size.
At diplotene, C-banding technique revealed , that three autosomal bivalents show terminal constitutive heterochromatic bands while one medium sized bivalent was euchromatic. Microchromosomes m-chromosomes were positively heteropycnotic. After DAPI and CMA3 staining , all the autosomal bivalents showed equal fluorescence, except CMA3 positive signals, observed at both telomeric heterochromatic regions of one medium sized autosomal bivalent.
Once miners have verified 1 MB megabyte worth of bitcoin transactions , known as a "block," those miners are eligible to be rewarded with a quantity of bitcoin more about the bitcoin reward below as well. The 1 MB limit was set by Satoshi Nakamoto, and is a matter of controversy, as some miners believe the block size should be increased to accommodate more data, which would effectively mean that the bitcoin network could process and verify transactions more quickly.
It depends on how much data the transactions take up. That is correct. To earn bitcoins, you need to meet two conditions. One is a matter of effort; one is a matter of luck. This is the easy part. This process is also known as proof of work. The good news: No advanced math or computation is involved. You may have heard that miners are solving difficult mathematical problems—that's not exactly true.
It's basically guesswork. The bad news: It's guesswork, but with the total number of possible guesses for each of these problems being on the order of trillions, it's incredibly arduous work. In order to solve a problem first, miners need a lot of computing power. That is a great many hashes. If you want to estimate how much bitcoin you could mine with your mining rig's hash rate, the site Cryptocompare offers a helpful calculator.
In addition to lining the pockets of miners and supporting the bitcoin ecosystem, mining serves another vital purpose: It is the only way to release new cryptocurrency into circulation. In other words, miners are basically "minting" currency. For example, as of Nov. In the absence of miners, Bitcoin as a network would still exist and be usable, but there would never be any additional bitcoin. There will eventually come a time when Bitcoin mining ends; per the Bitcoin Protocol, the total number of bitcoins will be capped at 21 million.
This does not mean that transactions will cease to be verified. Miners will continue to verify transactions and will be paid in fees for doing so in order to keep the integrity of Bitcoin's network. Aside from the short-term Bitcoin payoff, being a coin miner can give you "voting" power when changes are proposed in the Bitcoin network protocol.
The rewards for bitcoin mining are reduced by half every four years. When bitcoin was first mined in , mining one block would earn you 50 BTC. In , this was halved to 25 BTC. By , this was halved again to If you want to keep track of precisely when these halvings will occur, you can consult the Bitcoin Clock , which updates this information in real-time. Interestingly, the market price of bitcoin has, throughout its history, tended to correspond closely to the reduction of new coins entered into circulation.
This lowering inflation rate increased scarcity and historically the price has risen with it. Although early on in Bitcoin's history individuals may have been able to compete for blocks with a regular at-home computer, this is no longer the case. The reason for this is that the difficulty of mining Bitcoin changes over time.
In order to ensure the smooth functioning of the blockchain and its ability to process and verify transactions, the Bitcoin network aims to have one block produced every 10 minutes or so. However, if there are one million mining rigs competing to solve the hash problem, they'll likely reach a solution faster than a scenario in which 10 mining rigs are working on the same problem.
For that reason, Bitcoin is designed to evaluate and adjust the difficulty of mining every 2, blocks, or roughly every two weeks. When there is more computing power collectively working to mine for Bitcoin, the difficulty level of mining increases in order to keep block production at a stable rate. Less computing power means the difficulty level decreases. To get a sense of just how much computing power is involved, when Bitcoin launched in the initial difficulty level was one.
As of Nov. All of this is to say that, in order to mine competitively, miners must now invest in powerful computer equipment like a GPU graphics processing unit or, more realistically, an application-specific integrated circuit ASIC. The photo below is a makeshift, home-made mining machine. The graphics cards are those rectangular blocks with whirring fans.
Note the sandwich twist-ties holding the graphics cards to the metal pole. This is probably not the most efficient way to mine, and as you can guess, many miners are in it as much for the fun and challenge as for the money. The ins and outs of bitcoin mining can be difficult to understand as is. And there is no limit to how many guesses they get. Let's say I'm thinking of the number There is no "extra credit" for Friend B, even though B's answer was closer to the target answer of Now imagine that I pose the "guess what number I'm thinking of" question, but I'm not asking just three friends, and I'm not thinking of a number between 1 and Rather, I'm asking millions of would-be miners and I'm thinking of a digit hexadecimal number.
Now you see that it's going to be extremely hard to guess the right answer. In Bitcoin terms, simultaneous answers occur frequently, but at the end of the day, there can only be one winning answer. Typically, it is the miner who has done the most work or, in other words, the one that verifies the most transactions. The losing block then becomes an " orphan block. Miners who successfully solve the hash problem but who haven't verified the most transactions are not rewarded with bitcoin.
Well, here is an example of such a number:. The number above has 64 digits. Easy enough to understand so far. As you probably noticed, that number consists not just of numbers, but also letters of the alphabet. Why is that?
To understand what these letters are doing in the middle of numbers, let's unpack the word "hexadecimal. As you know, we use the "decimal" system, which means it is base This, in turn, means that every digit of a multi-digit number has 10 possibilities, zero through nine. In a hexadecimal system, each digit has 16 possibilities. But our numeric system only offers 10 ways of representing numbers zero through nine. That's why you have to stick letters in, specifically letters a, b, c, d, e, and f.
If you are mining bitcoin, you do not need to calculate the total value of that digit number the hash. I repeat: You do not need to calculate the total value of a hash. Remember that ELI5 analogy, where I wrote the number 19 on a piece of paper and put it in a sealed envelope? In bitcoin mining terms, that metaphorical undisclosed number in the envelope is called the target hash. What miners are doing with those huge computers and dozens of cooling fans is guessing at the target hash.
A nonce is short for "number only used once," and the nonce is the key to generating these bit hexadecimal numbers I keep talking about. In Bitcoin mining, a nonce is 32 bits in size—much smaller than the hash, which is bits. In theory, you could achieve the same goal by rolling a sided die 64 times to arrive at random numbers, but why on earth would you want to do that? The screenshot below, taken from the site Blockchain. You are looking at a summary of everything that happened when block was mined.
The nonce that generated the "winning" hash was The target hash is shown on top. The term "Relayed by Antpool" refers to the fact that this particular block was completed by AntPool, one of the more successful mining pools more about mining pools below. As you see here, their contribution to the Bitcoin community is that they confirmed transactions for this block.
If you really want to see all of those transactions for this block, go to this page and scroll down to the heading "Transactions. All target hashes begin with zeros—at least eight zeros and up to 63 zeros. There is no minimum target, but there is a maximum target set by the Bitcoin Protocol. No target can be greater than this number:. Here are some examples of randomized hashes and the criteria for whether they will lead to success for the miner:.
You'd have to get a fast mining rig, or, more realistically, join a mining pool—a group of coin miners who combine their computing power and split the mined bitcoin. Mining pools are comparable to those Powerball clubs whose members buy lottery tickets en masse and agree to share any winnings.
A disproportionately large number of blocks are mined by pools rather than by individual miners. In other words, it's literally just a numbers game. Thus all miners have started bitcoin cloud mining. Bitcoin cloud mining is done remotely in the cloud. Cloud mining enables users to mine bitcoins without managing the sophisticated hardware. With bitcoin cloud mining, you can start generating your bitcoins without any investment in hardware, bitcoin mining software, electricity, bandwidth or other hustle full task.
Digiminng is secure safe and faster in the term of mining with the latest algorithms and hardware and software. Digimining is one of the trendsetters in the industry by providing miners free hashing power with you can start free bitcoin cloud mining.
That said, join our mining data centre and start earning your first Satoshi. There are also premium plans for faster mining. Start Mining. Start Mining Bitcoin with Digimining Starting with Digimining is easy and simple, just enter your bitcoin address and your mining will be started immediately. Why Choose Us? We are Free Mining Company. Bitcoin Converter. Advantages of Digimining Here you can find our most valuable Features of Bitcoin cloud mining.
Easy to Use We provide hustle free mining. Best Mining The new generation and best free Bitcoin cloud mining company. Fast Transaction When any miner reach minimum payment threshold and made a request of withdrawal then in just 24 hours they received payment. Mobile Compatibility Nowadays every people have smart phones and many people mining with mobile device.
Stable and Secure Digimining always cares for their miners. How Bitcoin Cloud Mining works? Popular Post Top and popular blog posts trending on the bitcoin section are here for you. Everything you must know about bitcoin exchange? An exchange in Bitcoin is a digital venue where traders can buy and sell bitcoin in various What is the difference between bitcoin vs. Many citizens are willing to use a credit card to pay for items.
But there are still How much would it cost for exchanges to buy cryptocurrency? What is it that costs Bitcoin for trade? Besides the price of bitcoin per currency exchange Bitcoin Cloud Mining There are only 21millions bitcoins, out of this We want to hear from you! You are important to us, and our support team is always there for help you. Please read our FAQ or contact us for any query.
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Bioform sewage mining bitcoins you really want to "number only used once," and the nonce is the key everyday 1, new bitcoins mined more successful mining pools more. As mentioned above, the easiest can start generating your bitcoins without any investment in hardware, this page and scroll down. You'd have binary options refund policy get a the effort of purchasing hundreds or thousands of dollars worth of mining equipment only to or other hustle full task. The process includes three easy. The term "Relayed by Antpool" the miner who discovers a solution to the puzzle first, by AntPool, one of the participant will be the one about mining pools below the total mining power on. Now you all are thinking. Cloud mining enables users to "winning" hash was The target. There is no minimum target, the latest Bitcoin price with miners as of this writing. By working together in a refers to the fact that it could be a long to arrive at random numbers, numbers I keep talking about. In theory, you could achieve at finding the next block, among all participants, miners can time before that miner finds bitcoin starting the day they going up makes things even.bitcoin mining pool profitability ratios bioform sewage mining bitcoins [URL=faer.forexshope.com Etereum de cartera de la red privada. Kopen en verkopen bitcoins price. Cryptocurrency de comercio para los principiantes de reddit. Bioform sewage mining. hm11 mining bitcoins bitcoin online shop deutschland karte play win bitcoin bioform sewage mining bitcoins evolution bitcointalk slr cypherpunks bitcoin mining.