Factors associated with diversity, quantity and zoonotic potential of ectoparasites on urban mice and voles

Wild rodents are important hosts for tick larvae but co-infestations with other mites and insects are largely neglected. Small rodents were trapped at four study sites in Berlin, Germany, to quantify their ectoparasite diversity. Host-specific, spatial and temporal occurrence of ectoparasites was determined to assess their influence on direct and indirect zoonotic risk due to mice and voles in an urban agglomeration. Rodent-associated arthropods were diverse, including 63 species observed on six host species with an overall prevalence of 99%. The tick Ixodes ricinus was the most prevalent species, found on 56% of the rodents. The trapping location clearly affected the presence of different rodent species and, therefore, the occurrence of particular host-specific parasites. In Berlin, fewer temporary and periodic parasite species as well as non-parasitic species (fleas, chiggers and nidicolous Gamasina) were detected than reported from rural areas. In addition, abundance of parasites with low host-specificity (ticks, fleas and chiggers) apparently decreased with increasing landscape fragmentation associated with a gradient of urbanisation. In contrast, stationary ectoparasites, closely adapted to the rodent host, such as the fur mites Myobiidae and Listrophoridae, were most abundant at the two urban sites. A direct zoonotic risk of infection for people may only be posed by Nosopsyllus fasciatus fleas, which were prevalent even in the city centre. More importantly, peridomestic rodents clearly supported the life cycle of ticks in the city as hosts for their subadult stages. In addition to trapping location, season, host species, body condition and host sex, infestation with fleas, gamasid Laelapidae mites and prostigmatic Myobiidae mites were associated with significantly altered abundance of I. ricinus larvae on mice and voles. Whether this is caused by predation, grooming behaviour or interaction with the host immune system is unclear. The present study constitutes a basis to identify interactions and vector function of rodent-associated arthropods and their potential impact on zoonotic diseases

Computer aided computation of one-core cascade circuit of HV voltage transformer

W artykule przedstawiono model matematyczny dwustopniowej, jednordzeniowej struktury elektromagnetycznej przekładnika napięciowego indukcyjnego. Podano jego opis analityczny dla chwilowych wartości napięć i prądów. Zbudowano schemat zastępczy umożliwiający wykorzystanie metody symbolicznej do opracowania komputerowego modelu symulacyjnego. Przedstawiono wybrane ekrany autorskiego programu komputerowego umożliwiającego realizowanie kolejnych kroków procesu projektowania.The issue of electromagnetic cascade structures involves, among others, the current transformers [1] and inductive voltage trans-formers [2]. The following paper is a result of continuation of effort taken by the authors to prepare mathematical model of multistage inductive voltage transformers [3, 4]. Other publications on the topic include [5] and [6]. The mathematical model of HV single-core double primary winding inductive voltage transformer is presented in the paper. The scheme of the transformer configuration in Fig. 1 can be characterized by relationships between instantaneous values of voltages, currents and magnetic flux density - presented in formulas (1). These expressions can be utilized in computer simulations scoped to trace graphs of waveforms for instantaneous values of primary and secondary voltages [7, 8]. Calculation results were verified against measurement results for physical models. The equivalent circuit presented in Fig. 2 and described with formulas (2) has been de-signed, allowing to develop a computer simulation model by means of symbolic method. The sample screens presented in the article originate from computer software enabling execution of successive steps of designing process. The developed calculation method for cascade structure of voltage transformer can be utilized in designing process of core and windings for "electrically inverted" structure, like the ones used in HV voltage transformers, where primary side acts as the low voltage winding

Computer software application for designing instrument transformers

W artykule przedstawiono autorskie programy komputerowe do obliczeń projektowych przekładników prądowych i napięciowych.The author’s computer programs for designing current and voltage transformers there are presented in the paper

Fine Diffraction Effects in Si Single Crystals Implanted with Fast Ar Ions and Annealed

The paper presents high-resolution X-ray diffraction studies performed for Si single crystal: as-grown, implanted with a 5×10$\text{}^{14}$ ions· cm$\text{}^{-2}$ dose of 3 MeV/n Ar ions, as well as implanted and annealed in a very high vacuum. The results are discussed on the basis of rocking curves and the mathematical analysis of the reciprocal space maps. It is shown that the lattice parameter is increased in an implanted part of the crystal, but long distance lattice curvature is not present. After annealing full relaxation of the crystal is stated

X-ray Study of Strain Relaxation in Heteroepitaxial AlGaAs Layers Annealed under High Hydrostatic Pressure

The effect of treatment at up to 1270 K under hydrostatic argon pressure, up to 1.2 GPa, on strain relaxation of AlGaAs layers was investigated by X-ray diffraction and related methods. The 1.5μm thick AlGaAs layers were grown by molecular beam epitaxy method on 001 oriented semi-insulating GaAs substrate at 950 K. An increase in intensity of X-ray diffuse scattering, originating from hydrostatic pressure-induced misfit dislocations, was observed for all treated samples. For the samples treated at 920 K during 1 h under 0.6 GPa, the diffuse scattering was confined to the [110] crystallographic direction perpendicular to the direction of dislocations. For the samples treated at 1.2 GPa at the same temperature and time conditions as for 0.6G Pa, a different behaviour is observed, namely the diffuse scattering extends along all azimuthal directions, indicating that dislocations are created in both [110] and [¯110] directions. The change of strain after the treatment was most pronounced for the samples treated at 1.2 GPa for 1 h at 920 K

Effect of high temperature-pressure on GaAs layers grown on vicinal Si substrates

The effect of high hydrostatic pressure - high temperature treatment on strain state of thin GaAs layers, grown on vicinal (001) Si substrate, misoriented towards [110] with different miscut angles and with two different orientations of GaAs layer in relation to the miscut direction, was investigated by X-ray diffraction methods. The strain of the GaAs layers and GaAs/Si samples bending decreases when subjected to the treatment at T = 670 K under enhanced hydrostatic pressure (1.2 GPa). Dependence between the stress-induced structural changes and the orientation of GaAs miscut angle as well as peculiarities of the temperature-pressure treatment were determined. It has been shown that the amount of relaxed strain depends on the initial defect structure of the GaAs/Si hetrostructure. After reannealing the samples at higher temperature (870 K - 1.2 GPa), the strain and sample bending were the same as that after the treatment at 670 K - 1.2 GPa but the defect structure of layers was improved

Detection of immunotoxicity using T-cell based cytokine reporter cell lines ("Cell Chip")

Safety assessment of chemicals and drugs is an important regulatory issue. The evaluation of potential adverse effects of compounds on the immune system depends today on animal experiments. An increasing demand, however, exists for in vitro alternatives. Cytokine measurement is a promising tool to evaluate chemical exposure effects on the immune system. Fortunately, this type of measurement can be performed in conjunction with in vitro exposure models. We have taken these considerations as the starting point to develop an in vitro method to efficiently screen compounds for potential immunotoxicity. The T-cell lymphoma cell line EL-4 was transfected with the regulatory sequences of interleukin (IL)-2, IL-4, IL-10, interferon (IFN)-gamma or actin fused to the gene for enhanced green fluorescent protein (EGFP) in either a stabile or a destabilised form. Consequently, changes in fluorescence intensity represent changes in cytokine expression with one cell line per cytokine. We used this prototype "Cell Chip" to test, by means of flow cytometry, the immunomodulatory potential of 13 substances and were able to detect changes in cytokine expression in 12 cases (successful for cyclosporine, rapamycin, pentamidine, thalidomide, bis(tri-n-butyltin)oxide, house dust mite allergen (Der p I), 1-chloro-2,4-dinitrobenzene, benzocaine, tolylene 2,4-diisocyanate, potassium tetrachloroplatinate, sodium dodecyl sulphate and mercuric chloride; unsuccessful for penicillin G). In conclusion, this approach seems promising for in vitro screening for potential immunotoxicity, especially when additional cell lines besides T-cells are included

Development of the "Cell Chip": a new in vitro alternative technique for immunotoxicity testing

Predictive testing of immunotoxicity associated with chemical compounds is complicated and cannot be accomplished with a single test. As most of the existing tests for immunotoxicity employ experimental animals, there is an increasing need for alternative tests in vitro. We have developed a new system for in vitro immunotoxicity testing, which employs changes in cytokine expression observed in vitro as an endpoint indicating potential for perturbation of the immune system in vivo. This system named "fluorescent cell chip" (FCC) is based on a number of genetically modified cell lines that regulate the expression of a transgene coding for fluorescent protein enhanced green fluorescent protein (EGFP) in a similar way as they regulate expression of IL-1beta, IL-2, IL-4, IFN-gamma, IL-10, TNF-alpha, and beta-actin. Morphological and functional features of selected cell lines expressing EGFP under the control of cytokine promotors were compared with maternal cell lines and this comparison showed that critical functional features of the maternal cell lines were preserved in EGFP expressing cells. Two chemicals with known immunotoxic activities, cyclosporine A and potassium tetrachloro-platinate(II), mediated compound-specific pattern of inhibition and activation of reporter gene expression. Thus, the "fluorescent cell chip" has demonstrated potential for application as a predictive screening test for immunomodulatory activities of chemicals. The major advantage of this approach is the possibility to apply this test in high throughput screening of high number of compounds for their well defined biological activit