Regarding geographical distribution and clinical relevance, the most common canine geohelminths are
, ancylostomatids, and
. Canine intestinal parasites from the soil and sand present an important ...potential serious human health hazard, especially for the children preschool and school – age. This paper aimed to establish the degree of contamination of soil and sand with zoonotic parasites from the canine feces and the degree of risk they could pose for human health in public places and playgrounds in the city of Niš. Our parasitological study involved 200 soil samples and 50 sand samples from the public parks in the city of Niš in southeastern Serbia (43°19′15″N, 21°53′45″ E). From several locations, about 100 g of soil and sand was collected based on the bioclimatic indices. Parasitological diagnosis was performed using conventional qualitative and quantitative coprological methods, abiding by the recommendations about the diagnosis of parasitic diseases. In 38 – 46 % of soil samples and 40 % of sand samples seven species of endoparasites were diagnosed. In the samples of soil, a medium and high degree of contamination with the ascarid
(14 – 22 %) was detected, as well as a low and medium degree of contamination with ancylostomatids (4 – 12 %), and in the samples of sand, a variable degree of contamination with the helminths
(26 %) and
(16 %) was found. A statistically significant difference was found in the contamination with
eggs between the samples of sand and samples of soil. The studied public surfaces represent the reservoir of zoonotic parasites, which is a public health problem requiring a synergistic action of several factors to be successfully resolved, i.e. the implementation of prevention, surveillance, and control measures.
A study was made on the prevalence of some parasitic infections appearing in domestic rabbits obtained from individual breeders in Serbia in order to improve the agricultural production of these ...animals. Aside from economic reasons (meat production and reproduction) rabbits are bred for the research purposes, and races are kept as household pets. For these reasons, among others, it is important to gain knowledge of medical culprits including causes of parasitic diseases that compromise their health, well-being and cause economic losses. This parasitological research was conducted in the period from 2010 to 2015 in 8 epidemiological regions of Serbia, on 433 rabbits as representative samples of different races (154 individuals up to 1 years of age and 279 individuals older than 5). Out of the total number of examined rabbits parasitic infections were established in 82.68% of animals. We detected 3 species of endoparasites (
Eimeria
spp.,
Trichostrongylus
spp., and
Passalurus ambiguus
) and 3 species of ectoparasites (Scabies from genera
Sarcoptes
,
Psoroptes
and
Notoedres
). In “kits” (small rabbits) coccidiosis was the most prevalent disease (50.65%), while in older animals trichostrongilidosis was common (39.07%). The most represented scabies infection was with the species
Psoroptes cuniculi
(12.01%). Aiming at better control on the health of rabbits, there is a growing need for continual monitoring of parasitic infections including appropriate diagnosis, application efficient therapeutic protocols and control measures.
This article presents the results of the compositional, structural and morphological study of geopolymers synthesized from metakaolin and an alkali activator. The study involved the investigation of ...the structural and chemical properties of the geopolymer, in addition to thermally treated geopolymers up to 600 and 900°C. The precursor of the geopolymer, and the geopolymer samples before and after the thermal treatment, were investigated by Fourier transformation infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and SEM analysis. The corrected average value of the ratio of silicon and aluminum in the geopolymer samples (SiGP:Al) is about 1.46, which suggests that the obtained geopolymer samples represent a mixture of roughly equal amounts of sialate and sialate-siloxo units. Annealing the geopolymer samples at 600°C decreases the amount of Si-ONa bonds and induces the cross-linking of polymer changes. At the same time, other sodium containing alumino-silicate phases are created. The thermal treatment at 900°C leads to a considerable reduction of oxygen and particularly sodium, followed by significant morphological changes i.e. formation of a complex porous structure. Additionally, a new semicrystaline phase appears. Both XRD and XPS results imply that this new phase may be nepheline and it is plausible that this phase begins to nucleate at temperatures below 900°C.
A measurement system comprised of an ultra-low-distortion function generator, lock-in amplifier, and semiconductor parameter analyzer is used for sensitive extraction of the small-signal thermal ...impedance network of bipolar devices and circuits. The extraction procedure is demonstrated through measurements on several silicon-on-glass NPN test structures. Behavioral modeling of the mutual thermal coupling obtained by fitting a multipole rational complex function to measured data is presented.
The electrothermal behavior of single- and two-finger bipolar transistors at medium- and high-current operations is studied through theoretical modeling, experimental measurements, and computer ...simulations. Bias conditions that border thermally stable and unstable operation regimes are described by novel analytical formulations, which for the first time include simultaneously all relevant parameters that weaken the electrothermal feedback at high currents such as ballasting resistors, current dependence of the base-emitter-voltage temperature coefficient, and high-injection effects. Hence, besides giving a correct description of thermal instability mechanisms, the developed formulations also allow the prediction and physical understanding of restabilization phenomena. The models are supported by measurements on silicon-on-glass n-p-n bipolar junction transistors and by simulation results from a novel SPICE-based electrothermal macromodel for bipolar transistors. Furthermore, the models are employed to analyze the influence of the germanium percentage in the base of SiGe heterojunction bipolar transistors on the thermal ruggedness of the device.
Analytical expressions for the electrothermal parameters governing thermal instability in bipolar transistors, i.e., thermal resistance R/sub TH/, critical temperature T/sub crit/ and critical ...current J/sub C,crit/, are established and verified by measurements on silicon-on-glass bipolar NPNs. A minimum junction temperature increase above ambient due to selfheating that can cause thermal breakdown is identified and verified to be as low as 10-20/spl deg/C. The influence of internal and external series resistances and the thermal resistance explicitly included in the expressions for T/sub crit/ and J/sub C,crit/ becomes clear. The use of the derived expressions for determining the safe operating area of a device and for extracting the thermal resistance is demonstrated.
A novel bulk-micromachined test structure is presented for the fast and reliable determination of the lateral thermal conductivity of thin films. The device is composed of a heater resistor and ...thermocouples that are fabricated in polysilicon (poly-Si), and the associated processing and DC measurement procedures are straightforward. The validity of the method is supported by numerical simulations and verified by experimental determination of the lateral thermal conductivity of aluminum (Al), aluminum nitride (AlN), p-doped poly-Si, and silicon nitride (SiN) thin films. For Al, an average value of 217 W m super(-1) K super(-1) was found for 1-mum thick layers. For the other layers, a number of thicknesses were studied, and the increase of thermal conductivity with thickness was effectively detected: for AlN, values from 7 to 11.5 W m super(-1) K super(-1) were found, and for p-doped poly-Si, values went from 21 to 46 W m super(-1) K super(-1) for thicknesses from 0.15 to 1 mum. For SiN, a value of 1.8 was extracted for layers thicker than 0.5 mum.
A novel silicon-on-glass integrated bipolar technology is presented. The transfer to glass is performed by gluing and subsequent removal of the bulk silicon to a buried oxide layer. Low-ohmic ...collector contacts are processed on the back-wafer by implantation and dopant activation by excimer laser annealing. The improved electrical isolation with reduced collector-base capacitance, collector resistance and substrate capacitance, also provide an extremely good thermal isolation. The devices are electrothermally characterized in relationship to different heat-spreader designs by electrical measurement and nematic liquid crystal imaging. Accurate values of the temperature at thermal breakdown and thermal resistance are extracted from current-controlled Gummel plot measurements.
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