Total Amount Of Sample Research Articles

Seroprevalence and risk factors associated with infection by Neospora caninum of dairy cattle in the state of Alagoas, Brazil

The objective of this study was to investigate the prevalence of anti-Neospora caninum antibodies in cattle from milk producing farms of the microregion of Batalha, state of Alagoas, Brazil, as well as to identify the risk factors associated with the infection. Blood samples were collected from 1,004 cattle of 17 farms for the serological investigation regarding the presence of anti-N. caninum antibodies by the Indirect Immunofluorescence Reaction Technique (IMRT). From the total amount of samples analyzed, 77/1,004 (7.67%) were positive and 927/1,004 (92.33%) were negative. The logistical regression identified that cattle from farms without consortium breeding have an infection risk 6.33 (p<0.001; C.I. 2.89-13.10) times higher than cattle from farms with that type of breeding. Cattle from farms where the aborted fetuses are not adequately buried have an infection risk 3.04 (p<0.001; C.I. 1.64-5.63) times higher than cattle from farms with adequate destination of these fetuses. Infection by N. caninum occurs in cattle of the investigated region. The factors identified in our study can be used as risk indicators, so that control measures could be implemented to avoid infection by N. caninum in the herds of this region.

The Implementation of Islamic Leadership and Islamic Organizational Culture and Its Influence on Islamic Working Motivation and Islamic Performance PT Bank Mu'amalat Indonesia Tbk. Employee in the Central Java

The purpose of this study is to analyze and to proof that implementation leadership and organizational culture have influences on working motivation as have influences on performance employee as Islamic perspective of PT. Bank Mu’amalat Indonesia in the Central Java. The population in this study is the total 268 employees of PT, Bank Mu’amalat Indonesia Tbk in Central Java. The total amount of sample in this study is 60 despondences at Mu’amalat Bank of Indonesia in Central Java. The hypothesis was examined by using Partial Least Square (PLS) statistical method to obtain causality relational result of each variable which was developed in the model. The result of this study shows that the responsibility of PT, Bank Mu’amalat Indonesia Tbk Employee in the Central Java in their working result is in good category quantitatively, but qualitatively is in incomplete category (kaffah). It happens because conventional employee’s performance indicators including ability, task execution, work discipline and corporate’s standart working was looked like just to realize corporate organizational purpose that is generally dominated by materialistic, capitalistic and even hedonistic concept without including ruhiyyah values which according to mu’min faith is absolute to be realized, because a mu’min is only work to find bless from Allah SWT. The Ruhiyyah aspect is connected with ghirah (desire) or employee’s vision and mission. The measurement standard of that aspect is level of synergy between ruhiyyah aspect or employee’s working result with the Islamic concept.

Considerations on the ideal sample shape for Total Reflection X-ray Fluorescence Analysis

Total Reflection X-ray Fluorescence analysis (TXRF) is widely used in semiconductor industry for the analysis of silicon wafer surfaces. Typically an external standard is used for the calibration of the spectrometer. This is sensitive to errors in quantification. For small sample amounts the thin film approximation is valid, absorption effects of the exciting and the detected radiation are neglected and the relation between sample amount and fluorescence intensity is linear. For higher total sample amounts deviations from linearity have been observed (saturation effect). These deviations are one of the difficulties for external standard quantification. A theoretical determination of the ideal TXRF sample shape is content of the presented work with the aim to improve the calibration process and therefore the quantification. The fluorescence intensity emitted by different theoretical sample shapes was calculated, whereby several parameters have been varied (excitation energy, density, diameter/height ratio of the sample). It was investigated which sample shape leads to the highest fluorescence intensity and exhibits the lowest saturation effect. The comparison of the different sample shapes showed that the ring shape matches the ideal TXRF sample shape best.

Responses of the Asian Citrus Psyllid to Volatiles Emitted by the Flushing Shoots of Its Rutaceous Host Plants

Diaphorina citri Kuwayama (Hemiptera: Psyllidae) carries Candidatus liberibacter spp., the putative causal agents of Huanglongbing. D. citri reproduces and develops only on the flushing shoots of its rutaceous host plants. Here we examined whether D. citri is attracted to host plant odors and a mixture of synthetic terpenes. Tests conducted in a vertically oriented Y-tube olfactometer showed that both males and females preferentially entered the Y-tube arm containing the odor from the young shoots of Murraya paniculata (L.) Jack and Citrus limon L. Burm. f. cultivar Eureka. Only males exhibited a preference for the odor of C. sinensis L., whereas the odor of C. x paradisi MacFadyen cultivar Rio Red was not attractive to both sexes. The volatiles emitted by young shoots of grapefruit cultivar Rio Red, Meyer lemon (Citrus x limon L. Burm.f.), and M. paniculata were analyzed by gas chromatograph-mass spectrometry. The samples were comprised of monoterpenes, monoterpene esters, and sesquiterpenes. The number of compounds present varied from 2 to 17, whereas the total amount of sample collected over 6 h ranged from 5.6 to 119.8 ng. The quantitatively dominant constituents were (E)-beta-ocimene, linalool, linalyl acetate, and beta-caryophyllene. The attractiveness of a mixture of synthetic terpenes, modeled on the volatiles collected from M. paniculata, was evaluated in screened cages in a no-choice test. At three observation intervals, significantly more individuals were trapped on white targets scented with the mixture than on unscented targets. These results indicate the feasibility of developing D. citri attractants patterned on actual host plant volatiles.

Redesigning the Serological Surveillance Program for Notifiable Avian Influenza in Belgian Professional Poultry Holdings

This study was aimed at redesigning the Belgian active surveillance program for domestic birds in professional poultry holdings based on a risk analysis approach. A stochastic quantitative analysis, combining all data sources, was run to obtain sensitivity estimates for the detection of an infected bird in the different risk groups identified. An optimal number of holdings for each risk group was then estimated on the basis of the different sensitivities obtained. This study proved to be a useful tool for decision makers, providing insight on how to reallocate the total amount of samples to be taken in the coming year(s) in Belgium, thus optimizing the field resources and improving efficiency of disease surveillance such as required by the international standards.

Detection of Dirofilaria spp. in Dogs by PCR

Knowing that dirofilariosis is an emerging zoonosis, little known and studied in Romania, the aim of the study was to determine the prevalence of Dirofilaria spp. infection in dogs, in the western part of Romania. Since there is no epidemiological study on Dirofilaria spp. infection in dogs in Romania by molecular techniques, we consider opportune to examine the positive samples by this technique. Between February 2008 and August 2009 a number of 188 blood samples, from dogs in Timis and Hunedoara Counties, were collected. From the total amount of samples 96 were from Timis County and 92 were collected from Deva dog shelter, Hunedoara County. Blood samples were examination by different methods: Fresh blood smear, modified Knott's method, Diro-test Speed® Diro/Heartworm (Bio Veto Test, France), ELISA technique (D. immitis antigen) (EVL Netherlands). The positive blood samples with microfilariae were examined by PCR technique used for specific detection of D. immitis and D. repens described by (Casiraghi et al., 2006), at the Faculty of Veterinary Medicine “Szent Istvan”, at Parasitology and Zoology Department, from Budapest, Hungary. All 8 dogs tested were positive for Dirofilaria repens infection

The impact of storm water runoff on a small urban stream

In urban areas, storm water runoff often transports various pollutants, some of which settle and form sediments. In order to have the comprehensive view of the ecological state of storm water runoff recipients, both water and sediments of the stream must be assessed. In the Baltic Sea Area, the Water Framework Directive & HELCOM Recommendations aim to prevent or minimise pollution caused by harmful substances arising from storm water runoff, in order to promote the ecological restoration of the Baltic Sea—one of the most vulnerable seas. The aim of the study was to investigate the toxicity of bottom sediments of a small storm water runoff recipient focusing on the potential impact of successive discharges of urban storm water. Some storm water runoff quality parameters and the toxicity of bottom sediments of recipients was studied in this research. During 9 years, at four discharge points, minimum four grab samples per year at each discharge point were taken for chemical characterisation. General parameters (pH, SS, BOD7, CODCr and TPH) in liquid phase samples were analysed according to standard methods. Annual limit values were taken from the Lithuanian EPA requirements for the management of storm water runoff with a focus on prevention and control of contamination. Eleven composite samples of stream bottom sediments, each consisting of ten sub-samples, were collected in 2006. Toxicity screening from sediments was performed using the plant Lepidium sativum according to modified I. Magone’s methodology (Magone I, Bioindication of phytotoxicity of transport emission. In: Kachalova O-L, Zinatne (eds) Bioindication of toxicity of transport emissions in the impact of highway emissions on natural environment. Riga, pp 108–116, 1989). The level of toxic impact of Lepidium sativum (compared to control) was assessed according to the modified method of Wang (Rev Environ Contam Toxicol 126:88–127, 1992). The mean pH of urban storm water runoff does not vary much from neutral, but range values are quite different, from 4.0 up to 8.7. The highest concentration of SS reached 800 mg L−1, TPH—2.4 mg L−1, BOD7—300 mg O2 L−1 and CODCr—1,400 mg L−1. The SS was above the limit in 64% of total amount of grab samples, TPH—37%, BOD7—41% and CODCr—55%. The toxicity analysis of the bottom sediments showed varying toxicity of bottom sediments along the stream. From nine analysed samples of bottom sediments, 30% had weak toxicity, 30% medium and 30% strong toxicity on the test organism plant L. sativum. There was one single sample with no toxic effects, so that the results showed that urban storm water has an unacceptable environmental impact on recipients. It was also indicated that storm water runoff discharge alone is not the potential source of toxicity of bottom sediments. The litter demonstrated a weak toxicity of bottom sediments as well. Most local authorities do not consider storm water runoff discharges to be a matter of great concern because they believe that surface runoff arising from rainfall is still relatively clean. The study showed that the current method of monitoring storm water runoff quality by chemical analyses is not the best tool for environmental impact assessment and must be combined with toxicity tests of bottom sediments of recipients. To avoid the environmental impact of storm water runoff more attention should be paid to the development and implementation of storm water runoff pollution prevention measures. The study implies that future research concerning the relationships between storm water runoff deposit characteristics and biological activities must be developed to evaluate the contamination potential of stream sediment deposits for local aquatic ecosystems. Further studies should be developed to characterise the activities of the microbial community of storm water runoff sediments, and to monitor bioremediation in situ.

A bio-inspired field estimation scheme for wireless sensor networks

This paper proposes and analyzes a bio-inspired field estimation scheme using wireless sensor networks. The proposed scheme exploits the temporal pattern of the sensed process to reduce the number of samples sent back to the sink by a sensor node and, as consequence, decrease the energy consumption in data transmission. The proposed scheme is orthogonal to the techniques that reduce the spatial density of collected samples deactivating nodes with similar measurements. Thus, the proposed scheme can be used along with these techniques. We present two variations of this scheme: a sample-bounded and an error-bounded. The sample-bounded limits the maximum number of samples sent back to the sink, while the error-bounded guarantees the observation of every event of interest. Results show that for very regular processes the scheme can reduce up to 90% the total amount of samples sent in the network and even for less regular processes the proposed scheme can reduce the total amount of samples sent from approximately 10 up to 20%, with small reconstruction errors.

Full conjugate analysis of normal multiple traits with missing records using a generalized inverted Wishart distribution.

A Markov chain Monte Carlo (MCMC) algorithm to sample an exchangeable covariance matrix, such as the one of the error terms (R0) in a multiple trait animal model with missing records under normal-inverted Wishart priors is presented. The algorithm (FCG) is based on a conjugate form of the inverted Wishart density that avoids sampling the missing error terms. Normal prior densities are assumed for the 'fixed' effects and breeding values, whereas the covariance matrices are assumed to follow inverted Wishart distributions. The inverted Wishart prior for the environmental covariance matrix is a product density of all patterns of missing data. The resulting MCMC scheme eliminates the correlation between the sampled missing residuals and the sampled R0, which in turn has the effect of decreasing the total amount of samples needed to reach convergence. The use of the FCG algorithm in a multiple trait data set with an extreme pattern of missing records produced a dramatic reduction in the size of the autocorrelations among samples for all lags from 1 to 50, and this increased the effective sample size from 2.5 to 7 times and reduced the number of samples needed to attain convergence, when compared with the 'data augmentation' algorithm.

Full conjugate analysis of normal multiple traits with missing records using a generalized inverted Wishart distribution

A Markov chain Monte Carlo (MCMC) algorithm to sample an exchangeable covariance matrix, such as the one of the error terms (R0) in a multiple trait animal model with missing records under normal-inverted Wishart priors is presented. The algorithm (FCG) is based on a conjugate form of the inverted Wishart density that avoids sampling the missing error terms. Normal prior densities are assumed for the 'fixed' effects and breeding values, whereas the covariance matrices are assumed to follow inverted Wishart distributions. The inverted Wishart prior for the environmental covariance matrix is a product density of all patterns of missing data. The resulting MCMC scheme eliminates the correlation between the sampled missing residuals and the sampled R0, which in turn has the effect of decreasing the total amount of samples needed to reach convergence. The use of the FCG algorithm in a multiple trait data set with an extreme pattern of missing records produced a dramatic reduction in the size of the autocorrelations among samples for all lags from 1 to 50, and this increased the effective sample size from 2.5 to 7 times and reduced the number of samples needed to attain convergence, when compared with the 'data augmentation' algorithm.

Collection of capillary electrophoresis fractions on a moving membrane.

AbstractDuring the last 10 years, capillary electrophoresis (CE) has developed into a powerful analytical method for a wide variety of applications. It tends to replace traditional slab-gel electrophoresis for the separation of complex biological samples (DNA, proteins, carbohydrates) (1). The ability to further analyze the separated components using specific secondary reactions, analogous to well-established methods such as the Southern blot (2) and direct blotting (3) is important for the full development of this rapidly growing method. The total amount of sample separated in CE is very small when compared to slab gels, but thanks to the sensitivity and miniaturization of modern detection methods, it may still be sufficient for many postseparation analysis applications, such as hybridization, sequencing, enzyme digestion, reamplification by polymerase chain reaction (PCR), and so on.KeywordsCapillary ElectrophoresisSeparation MediumCollection DeviceHydroxypropyl CelluloseFraction CollectionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Theoretical description and experimental observation of aerosol transport processes in laser ablation inductively coupled plasma mass spectrometry

The transport efficiency of laser-induced aerosols mainly influences the detection capabilities for high spatial resolution laser ablation microanalysis. Therefore, the volume of the ablation cell, the geometry, the gas flow pattern and the transfer tube to carry the aerosol into the ICP are important influences on the transport process and the signal structure. Four different ablation cell volumes, ranging from 0.25 to 63 cm3, in combination with various transfer tubes of different diameters and lengths were investigated. The signal structure was significantly modified by reducing the volume of the sample chamber by a factor of approximately 250. The peak height of single laser shot (aerosol density) was increased by a factor of 6, the signal width (aerosol dispersion) was reduced by a factor of 7 and the rinse time of the sample chamber was consequently shortened to approximately 1 s, thereby eliminating processes of sample recirculation within the cell. The gas flow pattern inside the cell was experimentally traced by introducing powder of different sizes (grain size <1 µm and <65 µm) inside the cell. An angle of 40° at the apex of the gas injection cone was observed at the tip of the inlet nozzle, for a 0.5 mm id nozzle and 1 L min−1 gas flow. The gas inlet nozzle ensured a steady, high efficiency flow, influencing the precision of the measurements. The amount of transported material was constant within the precision of the ablation process for optimized transport and ionization conditions in all ablation cells. The ablation in a sample cell of volume of 0.25 cm3 showed slightly reduced sample transport and a slightly longer rinse time than for a 1.5 cm3 cell, which could be an indication that with extremely reduced cell volumes aerosol–wall interaction might limit the transport efficiency. The variation of the transport tube diameter (4–7 mm) and length (1.5–6 m) showed an influence on the signal structure, but the total amount of sample transferred was not influenced. Nevertheless, the variation of the dispersion as a function of the total volume of the transport system (cell and tube) showed that cell volume more significantly influenced the signal structure. A mathematical model was developed to describe the structure of the signal in relation to the parameters of the ablation set-up and its scope is discussed.

Early endosomal maturation of MHC class II molecules independently of cysteine proteases and H-2DM.

Major histocompatibility complex (MHC) class II molecules bind and present to CD4(+) T cells peptides derived from endocytosed antigens. Class II molecules associate in the endoplasmic reticulum with invariant chain (Ii), which (i) mediates the delivery of the class II-Ii complexes into the endocytic compartments where the antigenic peptides are generated; and (ii) blocks the peptide-binding site of the class II molecules until they reach their destination. Once there, Ii must be removed to allow peptide binding. The bulk of Ii-class II complexes reach late endocytic compartments where Ii is eliminated in a reaction in which the cysteine protease cathepsin S and the accessory molecule H-2DM play an essential role. Here, we here show that Ii is also eliminated in early endosomal compartments without the intervention of cysteine proteases or H-2DM. The Ii-free class II molecules generated by this alternative mechanism first bind high molecular weight polypeptides and then mature into peptide-loaded complexes.

Proton conducting materials based on hydrofluorides

Proton conducting materials have a great potential in applications for new energy sources and inorganic membrane reactors, which are highly efficient, energysaving and friendly to the environment. The utilization of hydrogen energy is an important subject for a sustainable development of the society in the 21st century, where proton conducting and hydrogen semipermeable membrane materials play a key role. Proton conductivity and materials are a very interesting subject in solid state ionics; every two years there is an international conference on solid state proton conductors. Proton conducting polymers have made it possible to develop a new generation of electrical vehicles powered by polymer electrolyte fuel cells (PEFCs) [1]. Production of hydrogen and generation of electric power using fossil fuels require a membrane reactor or fuel cell operating at high temperatures (>600 ◦C). It thus relies on the use of inorganic proton-conducting or hydrogen semipermeable membrane materials. These materials can be used in devices for hydrogen-energy related applications in two modes: membrane device and fuel cell. Proton-conducting solid state fuel cells (SSFCs) for converting the energy of hydrogen containing fuel have some advantages compared with oxygen-ion conducting solid oxide fuel cells (SOFCs). For stationary fuel cell plants operating at intermediate temperatures (say 400 to 800 ◦C), the use of inorganic proton conductors as electrolytes is very promising [2–4]. However, there is a need for even higher proton conductivity in order to improve the power output. In this work a high proton conductivity and good fuel cell performance are shown for a new type of materials based on MF-BaF2-CaH2 (M= Li, Na) hydrofluoride electrolytes although some reports claimed they are hydride ion, H−, conductors [5–7]. In order to enhance the mechanical properties, the MF-BaF2-CaH2 (M = Li, Na) hydrofluoride materials were prepared as a composite with Al2O3. The electrical properties of these hydrofluoride-composites were investigated as electrolytes in hydrogen-air fuel cells, a new method developed for investigating the systems with variability in the stoichiometry [8]. The fuel cells were constructed in the following way: (fuel gas, H2) Pt paste (Leitplatin 308A, Hanau, Germany)/ hydrofluoride-based electrolyte/Pt paste or Ag paste (Leitsilber 200, Hanau, Germany) (oxidant gas, 2% O2 in Ar). The hydrofluoride-based materials were prepared from LiF, NaF, BaF2, Al2O3 and CaH2. The LiF (or NaF), BaF2 and Al2O3 powders were first heated at 800 ◦C for 2 h, then Li (Na)F-BaF2-Al2O3 was mixed with CaH2 (about 20 mol% of the total sample amount) and heated again in a hydrogen atmosphere at 700 ◦C for 1 h to synthesize CaH2 with Li (Na)F-BaF2-Al2O3 as hydrofluoride type ceramics. In the fuel cells, the electrodes are non-blocking only for H+, H− or O2− mobile ionic charge carriers, since the electrodes are supplied with gas from external gas resources; for ions such as Li+, F− etc. the electrodes are blocking; these ions will thus not make a contribution to the stable fuel cell current output during fuel cell operation. The conductivity of the hydrofluoridebased electrolytes was obtained from measurements of the fuel cell I -V characteristics in subtraction of the influence from the electrodes. It should be mentioned that the conductivity obtained from the fuel cells correspond directly to the proton or oxygen ion conduction [8]. Fig. 1 shows typical I -V characteristics for a fuel cell with the electrolyte, LiF-BaF2-CaH2-Al2O3, see Fig. 1a, and the I -P characteristics at 740 ◦C, see Fig. 1b. In the I -V characteristics, the linear section in the central region reflects the IR loss mainly caused by the electrolyte, from which the resistance, and thus the conductivity of the electrolyte can be calculated, as shown in Fig. 1. Using ionic doping and forming composites with Al2O3 can significantly enhance the conductivity of the fluorides. For example, MF (M=Li, Na,) doped BaF2-Al2O3 has a conductivity of 10−3 to 10−2 S/cm for temperatures above 600 ◦C, while for

Accelerator Mass Spectrometry Analysis of Non-Soluble Carbon in Aerosol Particles from High Alpine Snow (Mt. Sonnblich, Austria)

With an elaborate accelerator mass spectrometry (AMS) technique radiocarbon measurements have been performed with aerosol carbon filtered from high alpine snow samples gathered consecutively at the high-altitude research station Sonnblick (3106 m, Eastern Alps, Austria) during a snow storm in April 1997. The concentration of the water-insoluble carbonaceous material in the molten snow was on the average 310 μg C/L and the total sample amounts for analysis were in the range of 35 μg to 60 μg C. Using a special background correction procedure tested on similar amounts of an urban particulate standard sample the accuracy of the corrected and normalized 14C/12C isotopic ratios of the snow aerosol samples was in the order of 4% to 14% of the measured ratios. The water-insoluble carbonaceous material of five samples from Mt. Sonnblick exhibited a weighted mean of 74 pMC (percent Modern Carbon) with a range of 64 pMC to 88 pMC. Thus, it appears that about 64% of non-soluble carbon in high alpine snow from Sonnblick was of biogenic origin. The temporal variations of the 14C/12C isotopic ratios of the snow aerosol samples were statistically significant, suggesting alterations in the contribution of specific aerosol sources.

Trapping efficiency of polyurethane foam and amberlite XAD-2 for various organochlorine compounds

The trapping efficiency of polyurethane foam (PUF) and Amberlite XAD-2 have been investigated for various OCPs. Atmospheres containing different concentrations of 16 OCPs have been generated and trapped in the solid adsorbent cartridges. Conditions such as the adsorption by the cartridges, the extraction of the compounds, the evaporation of the final solution, the breakthrough value and the analysis of the compounds by GC/ECD have been studied. The adsorption efficiency has been better on PUF than on Amberlite XAD-2. Recovery values ranging from 80% for p-p′ TDE to 105% for heptachlor are obtained, most of them being higher than 90%. The relative standard deviation values for the compounds investigated are less than 5% for a total sample amount of 0.2 μg of each compound.

Effect of multiple sprayers on dynamic range and flow rate limitations in electrospray and ionspray mass spectrometry

AbstractThe sample‐ion signal in electrospray mass spectrometry is an approximately linear function of sample concentration up to 10−5mol/L. Dynamic range for the tetrabutylammonium ion signal and spray current leaving the nebulizer are determined with one and two sprayers, at flow rates of 5 and 10 μL/min, and at different positions of the sprayer. The dynamic range does not appear to be limited by the total amount (mass) of sample, but by the concentration of the sample solution introduced into the ion source, as is demonstrated by the use of two parallel sprayers. Limitation of dynamic range as a result of increasing repulsion between charged droplets at higher sample concentration appears to be unlikely. The efficiency of droplet charging gradually decreases with increasing sample concentration, while the detector signal abruptly reaches a plateau. Limitation just by insufficient charge on droplets is ruled out. Limitation of sample‐ion signals can be attributed to an upper limit to the number of free quaternary ammonium ions at the surface of electrically charged droplets.Multiple sprayers can be used to increase the range of flow rates accepted by the electrospray interface. In the case of ionspray (pneumatically assisted electrospray) the stability of the ion signal at higher flow rates is improved by the use of multiple sprayers.

Application of in situ TG to characterize catalyst acidity

The acidity of several types of catalyst was measured by means of in situ TG, using the procedure of NH 3 adsorption—desorption, with a modified quartz furnace tube on a Du Pont 9900 Computer/Thermal Analysis System. HY and HZSM-5 zeolites were used as reference samples to test the repeatability and/or precision of this method. The total acid amount and acid strength of samples could be directly calculated from the mass change on TG—DTG curves of NH 3 adsorption—desorption. The relative standard deviation of the data which were collected from five measurements of HY is less than ±0.050. This result was examined using HZSM-5 and the data were comparable with those reported in the literature. The relations between the acidities and the catalytic activities for Pt/MgO-cross linked montmorillonite (Pt/MgO-CLM) and β zeolite catalysts are also discussed.

Determination of organohalogen compounds and organic carbon as sum parameter in electronic waste

Metal-containing devices in electronic waste such as printed circuit boards can be recycled for the recovery of noble metals such as gold, silver, platinum or palladium using a thermal process. In this process the plastics are burned and more than 90% of the noble metals are transfered into a copper matrix. Finally the pure metals are refined by electrolysis. Because of the content of brominated flame retardants and chlorinated polymers in the plastics, formation of halogenated dibenzo-p-dioxins and dibenzofurans cannot be excluded. The use of modern filter techniques minimizes the emission of these substances. As a precaution the electronic waste is controlled for its content of organohalogen compounds and organic carbon. This work describes an analytical method for the determination of the sum of organohalogen compounds and organic carbon in electronic waste. The investigation of different charges of electronic waste in the fraction of particle size<0.1 mm show concentrations for the sum of organobromine compounds in the range of 0.2–4.8% originating from brominated flame retardants in the plastics. The total content of organochlorine compounds is <0.01–0.13%, showing that chlorinated plastics were efficiently removed before the thermal process. The content of organic carbon is between 13 and 27%. Because of the portion of fine particle size in relation to the total sample amount, the results have to be multiplied by a factor of about 0.25 to 0.3.

High-performance liquid chromatographic analysis of cyclosporine A in human skin.

A three-dimensional high-performance liquid chromatography (HPLC) method is described for the determination of cyclosporine A in human skin. The method allows to determine at least 3 ng cyclosporine A in 10 mg skin (total sample amount needed) and is suitable for cyclosporine A level monitoring in the skin of psoriatic patients.