270 research outputs found

    The role of non-commercial cyprinids in maintenance and spread of the opisthorchiasis focus in the middle Ob River basin (Tomsk region, Russia)

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    The study assessed the role of non-commercial cyprinid species in maintaining the opisthorchiasis focus in the middle Ob River basin, Tomsk region, Russia. The source of O. felineus infection for humans and carnivores is fish of the family Cyprinidae. This is the most numerous family, 14 species live in the middle Ob River basin, which includes 6 commercial species and 8 non-commercial species. This study aimed to investigate the current situation on infestation of non-commercial cyprinids with O. felineus metacercariae and their role in maintaining and spreading the natural focus of opisthorchiasis in the middle Ob River basin. We investigated 4 non-commercial species (tench, sunbleak, common bleak, gudgeon), which are highly abundant in water bodies. Tench, common bleak and gudgeon are objects of amateur fishing. These species are traditionally included in the diet of the local population. Opisthorchis felineus metacercariae were recorded in muscles of all the examined fish species. The identification of metacercariae was confirmed by morphological methods and PCR diagnostics. Tench and sunbleak are the main sources of opisthorchiasis infection in the floodplain lakes of the Ob River basin (the prevalence of tench infection is 89.3% and mean intensity of infection is 11.2 metacercariae per fish, the prevalence of sunbleak infection is 50.9% and the intensity of infection is 4.25 metacercariae per fish). The prevalence of infection in the introduced common bleak from the rivers of the middle Ob River basin is rapidly increasing from 2.4 (2016-2018) to 37.5% (2020-2021), and mean intensity of infection increased from 1 to 4.15. The epizootic state of water bodies in the middle Ob River basin remains unfavorable in relation to opisthorchiasis. Tench, common bleak and sunbleak, along with ide and dace, are the main source of infection for humans and animals, which is evidenced by high infection with Opisthorchis felineus metacercariae in these numerous fish species. They pose the greatest danger of infection of people and animals with opisthorchiasis. These species should be included in the campaign to avoid raw and poorly cooked fish in the diet. In addition, such species as roach, bream and sunbleak also pose the danger of infection with opisthorchiasis, but to a lesser extent

    Применение двухточечного метода калибровки для тепловизионных матриц фирмы ULIS

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    The objective of this work is research and modification of the two-point calibration method for long wavelength infrared uncooled microbolometer ULIS' matrices. The ultimate goal is to obtain better thermal image for the end-user, where quality criteria are such characteristics as a visual contrast, ability to distinguish fine details, and noisy image as less as possible.In considering the most common calibration algorithm of infrared uncooled microbolometer matrices we used the study results of other authors in which results and comparative analyses of the most effective algorithms were provided. Based on these investigations, to make modification have been chosen quite effective and at the same time simple computationally two-point calibration method, which is sufficient for most tasks entrusted to thermal imager.Modification of the two-point calibration method involves introducing variable reference voltages, which nominal values depend on the temperature range of the matrix. In the original version of the algorithm a reference voltage was selected for the whole range of possible temperatures of the matrix, which did not guarantee the required level of minimum sensitivity. The results of the algorithm embedded in a real device and experimental results proved the effectiveness of this modification.The known specialized literature describing calibration methods for long wavelength infrared uncooled microbolometer matrices do not mention this type of modification.The method described in this publication can be applied to various practical implementations of the thermal imagers without cover and algorithms, which can improve image quality.The article shows advisability and effectiveness of using the modified two-point calibration method for design of thermal imagers without cover with a wide range of operating temperatures.Приводятся краткий обзор наиболее распространённых на текущее время методов калибровки (двухточечная и многоточечная) и вариант модифицированного алгоритма двухточечной калибровки приборов бесшторкового типа, построенных на основе неохлаждаемых микроболометрических матриц фирмы ULIS (Long Wavelength Infrared uncooled microbolometer). В статье отражены описание процедуры калибровки, получения результатов, кратко описан интерфейс программы, реализованной на языке С и используемой в данной работе, а так же сам прибор, используемый для апробации модифицированного алгоритма. Результаты данной работы могут быть интересны при практической реализации бесшторковых тепловизоров и алгоритмов улучшения качества изображения

    Non-universal equilibrium crystal shape results from sticky steps

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    The anisotropic surface free energy, Andreev surface free energy, and equilibrium crystal shape (ECS) z=z(x,y) are calculated numerically using a transfer matrix approach with the density matrix renormalization group (DMRG) method. The adopted surface model is a restricted solid-on-solid (RSOS) model with "sticky" steps, i.e., steps with a point-contact type attraction between them (p-RSOS model). By analyzing the results, we obtain a first-order shape transition on the ECS profile around the (111) facet; and on the curved surface near the (001) facet edge, we obtain shape exponents having values different from those of the universal Gruber-Mullins-Pokrovsky-Talapov (GMPT) class. In order to elucidate the origin of the non-universal shape exponents, we calculate the slope dependence of the mean step height of "step droplets" (bound states of steps) using the Monte Carlo method, where p=(dz/dx, dz/dy)$, and represents the thermal averag |p| dependence of , we derive a |p|-expanded expression for the non-universal surface free energy f_{eff}(p), which contains quadratic terms with respect to |p|. The first-order shape transition and the non-universal shape exponents obtained by the DMRG calculations are reproduced thermodynamically from the non-universal surface free energy f_{eff}(p).Comment: 31 pages, 21 figure

    Observation of Dispersion in the J=2+ Collective Modes of He-3-B by Nonlinear Acoustic Spectroscopy

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    Parametric excitation yields new results, which cannot be obtained by conventional linear spectroscopy, on the collective modes in superfluid He-3-B. In our ultrasonic experiments, performed in a chamber with four quartz crystals, we have excited the real squashing (J = 2+) modes by two simultaneous sound waves which are mutually either parallel, orthogonal, or antiparallel. Qualitatively these results are in agreement with the theoretical dispersion relation of the J = 2+ modes, and quantitatively we have been able to extract the collective-mode velocities from the line splittings in zero magnetic field

    Genetic characterization of clinical <I>Klebsiella</I> isolates circulating in Novosibirsk

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    72 clinical strains of Klebsiella spp. isolated from samples obtained from humans in Novosibirsk, Russia, were analyzed. Species identification of strains was performed using 16S rRNA and rpoB gene sequences. It was revealed that Klebsiella pneumoniae strains were dominant in the population (57 strains), while the remaining 15 strains were K. grimontii, K. aerogenes, K. oxytoca and K. quasipneumoniae. By molecular serotyping using the wzi gene sequence, K. pneumoniae strains were assigned to twenty-one K-serotypes with a high proportion of virulent K1- and K2-serotypes. It was found that K. pneumoniae strains isolated from the hospitalized patients had a higher resistance to antibiotics compared to the other Klebsiella species. Real-time PCR revealed that the population contained genes of the blaSHV, blaTEM, blaCTX families and the blaOXA-48 gene, which are the genetic determinants of beta-lactam resistance. It has been shown that the presence of the blaCTX sequence correlated with the production of extended-spectrum beta-lactamases, and phenotypic resistance to car-bapenems is due to the presence of the blaOXA-48 gene. At the same time, the carbapenemase genes vim, ndm, kpc, imp were not detected. Among the aminoglycoside resistance genes studied, the aph(6)-Id and aadA genes were found, but their presence did not always coincide with phenotypic resistance. Resistance to fluoroquinolones in the vast majority of strains was accompanied by the presence of the aac(6’)-IB-cr, oqxA, oqxB, qnrB, and qnrS genes in various combinations, while the presence of the oqxA and/or oqxB genes alone did not correlate with resistance to fluoroquinolones. Thus, the detection of blaCTX and blaOXA-48 can be used to quickly predict the production of extended-spectrum beta-lactamases and to determine the resistance of Klebsiella to carbapenems. The detection of the aac(6’)-Ib-cr and/or qnrB/qnrS genes can be used to quickly determine resistance to fluoroquinolones

    Magnetic phenomena in co-containing layered double hydroxides

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    Magnetic behavior of CoII(n)AlIII layered double hydroxides (LDHs) (n=Co/Al=2 and 3) intercalated with nitrate was studied as a function of temperature. Both LDH compounds are paramagnetic above about 8K. A rapid increase of their magnetic moments occurs below this temperature until the moments reach the maximum values at Tmax of 4.0K and 3.2K for Co(2)Al-NO3 and Co(3)Al-NO3, respectively. Below Tmax, the zero-field-cooled and the field-cooled static magnetization curves are strongly different. Along with this low-temperature phenomena, Co(2)Al-NO3 and Co(3)Al-NO3 demonstrate anomalous behavior of their temperature dependence magnetic susceptibility in a highertemperature range: between 75 and 175K, both the paramagnetic Curie temperature and the effective magnetic moment change in a non-monotonous way. Possible structural reasons of the observed magnetic behavior of the CoII(n)AlIII LDHs are discussed.publishe

    High-power ultrasonic synthesis and magnetic-field-assisted arrangement of nanosized crystallites of cobalt-containing layered double hydroxideu

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    High-quality stoichiometric Co2Al–NO3 and Co2Al–CO3 layered double hydroxides (LDHs) have been obtained by precipitation followed by anion exchange, both high-power sonication assisted. Application of high-power ultrasound has been demonstrated to result in a considerable acceleration of the crystallization process and the anion-exchange reaction. Two independent approaches were used to form bulk and 2-D samples of Co2Al–NO3 with the oriented crystallites, namely uniaxial pressing of deposits from sonicated LDH slurries and magnetic field assisted arrangement of LDH crystallites precipitating on glass substrates. A convenient way of preparation of semi-transparent compacts with relatively big blocks of oriented crystallites have been demonstrated. Thin dense transparent films of highly-ordered crystallites of Co2Al–NO3 LDH have been produced and characterized.publishe

    4D Imaging and Diffraction Dynamics of Single-Particle Phase Transition in Heterogeneous Ensembles

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    In this Letter, we introduce conical-scanning dark-field imaging in four-dimensional (4D) ultrafast electron microscopy to visualize single-particle dynamics of a polycrystalline ensemble undergoing phase transitions. Specifically, the ultrafast metal–insulator phase transition of vanadium dioxide is induced using laser excitation and followed by taking electron-pulsed, time-resolved images and diffraction patterns. The single-particle selectivity is achieved by identifying the origin of all constituent Bragg spots on Debye–Scherrer rings from the ensemble. Orientation mapping and dynamic scattering simulation of the electron diffraction patterns in the monoclinic and tetragonal phase during the transition confirm the observed behavior of Bragg spots change with time. We found that the threshold temperature for phase recovery increases with increasing particle sizes and we quantified the observation through a theoretical model developed for single-particle phase transitions. The reported methodology of conical scanning, orientation mapping in 4D imaging promises to be powerful for heterogeneous ensemble, as it enables imaging and diffraction at a given time with a full archive of structural information for each particle, for example, size, morphology, and orientation while minimizing radiation damage to the specimen
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