43 research outputs found

    Selenium deficiency impairs host innate immune response and induces susceptibility to Listeria monocytogenes infection

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    <p>Abstract</p> <p>Background</p> <p>Susceptibility or resistance to infection with <it>Listeria monocytogenes </it>correlates with Selenium (Se) deficiency in response to infection.</p> <p>Results</p> <p>Se-deficient mouse models of listeriosis were used to study the innate immune response during the course of <it>L. monocytogenes </it>infection. Blood samples from mouse models were used for Se status. The concentration of MDA, SOD, GPx and CAT in blood has revealed that lower Se level exist in Se-deficient mice. Intestine, mesenteric lymph node, liver, spleen and brain from each mouse were to study the bacterial burden in organs. The analysis of cell types of spleen from Se-deficient mice revealed that the ability of the host to elicit a rapid recruitment and activation of systemic innate immune response to infection was to a certain extent compromised under conditions of Se deficiency. The cytokine levels in the serum and cytokine expression levels in the livers from Se-deficient mice revealed that the innate immune response of Se-deficient mice was impaired throughout the course of infection. These results suggest that innate immune response is altered by Se deficiency after infection with <it>L. monocytogenes</it>.</p> <p>Conclusion</p> <p>In conclusion, induced susceptibility of host resistance is associated with an impaired innate immune response following infection with <it>L. monocytogenes </it>in C57BL/6 Se-deficient mice.</p

    Parasite Species Associated With Wild Plateau Pika (Ochotona Curzoniae) In Southeastern Qinghai Province, China

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    A survey was conducted to determine the prevalence and seasonal abundance of egg, larval, and adult stages of helminths; oocyts of protozoans; and ectoparasites of plateau pikas (Ochotona curzoniae) in seven areas of southeastern Qinghai Province, China, during August 2006 and May 2007. Fecal samples collected from 430 plateau pikas were examined by the modified McMaster technique, which revealed that 83% of the samples contained eggs from two or more helminth species. Mean fecal egg counts were generally moderate and showed the same trend irrespective of the age or sex of the pikas. The prevalence and counts of cestode eggs showed strong seasonal relationships that corresponded with the rainfall pattern in the study area during the study period. Of the 430 plateau pika examined at necropsy, 89% contained adult nematode or cestode species, but none of these contained adult trematode species or protozoans. Overall, six genera of adult nematodes including Oesophagostomum sp., Cephaluris coloradensis, Eugenuris schumakowiescsi, Haemonchus sp., Trichuris sp., and Chbertiinae sp.; three genera of adult cestodes including Schizorchis sp., Ochotonae sp., and Hymenolepis nana; three ectoparasite species including Hypoderma curzonial, Pulex sp., and Ixodes ovatus; and one proscolex stage of a cestode, Echinococcus multilocularis or Echinococcus shiquicus, were encountered during the study. Other genera examined occurred in low numbers, which did not allow any meaningful comparisons. Overall, results suggest that four parasite species, Hypoderma curzonial, Pulex sp., Ixodes ovatus Neumann, and Cephaluris coloradensis, may be regulating factors in controlling future numbers of plateau pika in this study area. These data provide evidence of a natural biologic control mechanism of plateau pika on grassland habitats, and may be of use for identifying the mechanism of transmission of parasites between plateau pika, livestock, and humans

    The emission positions of kHz QPOs and Kerr spacetime influence

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    Based the Alfven wave oscillation model (AWOM) and relativistic precession model (RPM) for twin kHz QPOs, we estimate the emission positions of most detected kHz QPOs to be at r=18+-3 km (R/15km) except Cir X-1 at r = 30\+-5 km (R/15km). For the proposed Keplerian frequency as an upper limit to kHz QPO, the spin effects in Kerr Spacetime are discussed, which have about a 5% (2%) modification for that of the Schwarzchild case for the spin frequency of 1000 (400) Hz.The application to the four typical QPO sources, Cir X-1, Sco X-1, SAX J1808.4-3658 and XTE 1807-294, is mentioned.Comment: Science China, Physics, Mechanics & Astronomy, 2010, 53, NO.

    PSR J1926-0652: A Pulsar with Interesting Emission Properties Discovered at FAST

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    We describe PSR J1926-0652, a pulsar recently discovered with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using sensitive single-pulse detections from FAST and long-term timing observations from the Parkes 64-m radio telescope, we probed phenomena on both long and short time scales. The FAST observations covered a wide frequency range from 270 to 800 MHz, enabling individual pulses to be studied in detail. The pulsar exhibits at least four profile components, short-term nulling lasting from 4 to 450 pulses, complex subpulse drifting behaviours and intermittency on scales of tens of minutes. While the average band spacing P3 is relatively constant across different bursts and components, significant variations in the separation of adjacent bands are seen, especially near the beginning and end of a burst. Band shapes and slopes are quite variable, especially for the trailing components and for the shorter bursts. We show that for each burst the last detectable pulse prior to emission ceasing has different properties compared to other pulses. These complexities pose challenges for the classic carousel-type models.Comment: 13pages with 12 figure

    Investigation of C-band pumping for extended L-band EDFAs

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    In this study, we present systematic numerical and experimental analysis of high-power C-band light pumping in extended L-band EDFAs. We investigate, for the first time to our best knowledge, how C-band light sources can be used as pump sources to extend the bandwidth of L-band EDFAs beyond 1610 nm. Results show that, when using a C-band light source as the sole pump, efficient amplification is obtained over the extended L-band but at the expense of higher noise figure. However, the advantage of C-band pumping in terms of power conversion efficiency can be exploited when using a two-stage EDFA, with a first stage pumped by 1480 nm to maintain good noise figure performance and a high-power C-band light source (up to several hundred mW) as the pump source for the second stage. Thus, a 20-dB gain covering 1570-1618 nm with a maximum noise figure of 5.7 dB is demonstrated

    Parasite Species Associated With Wild Plateau Pika (Ochotona Curzoniae) In Southeastern Qinghai Province, China

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    A survey was conducted to determine the prevalence and seasonal abundance of egg, larval, and adult stages of helminths; oocyts of protozoans; and ectoparasites of plateau pikas (Ochotona curzoniae) in seven areas of southeastern Qinghai Province, China, during August 2006 and May 2007. Fecal samples collected from 430 plateau pikas were examined by the modified McMaster technique, which revealed that 83% of the samples contained eggs from two or more helminth species. Mean fecal egg counts were generally moderate and showed the same trend irrespective of the age or sex of the pikas. The prevalence and counts of cestode eggs showed strong seasonal relationships that corresponded with the rainfall pattern in the study area during the study period. Of the 430 plateau pika examined at necropsy, 89% contained adult nematode or cestode species, but none of these contained adult trematode species or protozoans. Overall, six genera of adult nematodes including Oesophagostomum sp., Cephaluris coloradensis, Eugenuris schumakowiescsi, Haemonchus sp., Trichuris sp., and Chbertiinae sp.; three genera of adult cestodes including Schizorchis sp., Ochotonae sp., and Hymenolepis nana; three ectoparasite species including Hypoderma curzonial, Pulex sp., and Ixodes ovatus; and one proscolex stage of a cestode, Echinococcus multilocularis or Echinococcus shiquicus, were encountered during the study. Other genera examined occurred in low numbers, which did not allow any meaningful comparisons. Overall, results suggest that four parasite species, Hypoderma curzonial, Pulex sp., Ixodes ovatus Neumann, and Cephaluris coloradensis, may be regulating factors in controlling future numbers of plateau pika in this study area. These data provide evidence of a natural biologic control mechanism of plateau pika on grassland habitats, and may be of use for identifying the mechanism of transmission of parasites between plateau pika, livestock, and humans

    Investigation of Bi-Directionally, Dual-Wavelength Pumped Extended L-Band EDFAs

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    Investigation of Ionic Liquids as Extraction Solvents for Separating Bicyclic Aromatic S/N-Compounds from FCC Diesel

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    To improve the quality of fluid catalytic cracking (FCC) diesel, ionic liquids (ILs) were used as promising neoteric solvents to extract bicyclic S/N-compounds (quinoline and 1-benzothiophene) from FCC model oil. In addition to the thermodynamic properties, including solvent capacity and selectivity, physical properties such as viscosity and thermal stability are also considered as important factors in the IL screening process. 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2MIM][NTF2]) was selected as the most suitable extraction solvent by the COSMO-RS model, and the accuracy of this model was verified based on the collected experimental data. Liquid–liquid equilibrium experiments were performed to study the effects of the initial quinoline and 1-benzothiophene concentrations, mass solvent ratio, extraction stages, and the presence of other aromatics on the extraction efficiency. Then, the extraction mechanism and the differences in the extraction effects for the quinoline and 1-benzothiophene systems were explored by quantum chemical calculation and molecular dynamics simulation. The consistency between experiments and theoretical calculation indicates that the electrostatic interaction is the main reason for the difference in the extraction efficiency between the quinoline and 1-benzothiophene systems

    PART1 and hsa-miR-429-Mediated SHCBP1 Expression Is an Independent Predictor of Poor Prognosis in Glioma Patients

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    Gliomas are the most common primary brain tumors. Because of their high degree of malignancy, patient survival rates are unsatisfactory. Therefore, exploring glioma biomarkers will play a key role in early diagnosis, guiding treatment, and monitoring the prognosis of gliomas. We found two lncRNAs, six miRNAs, and nine mRNAs that were differentially expressed by analyzing genomic data of glioma patients. The diagnostic value of mRNA expression levels in gliomas was determined by receiver operating characteristic (ROC) curve analysis. Among the nine mRNAs, the area under the ROC curve values of only CEP55 and SHCBP1 were >0.7, specifically 0.834 and 0.816, respectively. Additionally, CEP55 and SHCBP1 were highly expressed in glioma specimens and showed increased expression according to the glioma grade, and outcomes of high expression patients were poor. CEP55 was enriched in the cell cycle, DNA replication, mismatch repair, and P53 signaling pathway. SHCBP1 was enriched in the cell cycle, DNA replication, ECM receptor interaction, and P53 signaling pathway. Age, grade, IDH status, chromosome 19/20 cogain, and SHCBP1 were independent factors for prognosis. Our findings suggest the PART1-hsa-miR-429-SHCBP1 regulatory network plays an important role in gliomas
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