5,626 research outputs found
Desenvolvimento e validação de método multirresíduos para determinação de resíduos de agrotóxicos em pólen apícola por GC-MS/MS ÍON TRAP.
Nutritional Immunomodulation as an Approach to Decreasing the Negative Effects of Stress in Poultry Production
Stress can lead to changes in the immune response resulting in both increased and decreased resistance to opportunistic bacterial pathogens. Growth-promoting antibiotics have been a major tool in modulating hostpathogen interactions and limiting clinical and subclinical bacterial infection in confined animal production. Regulatory pressures to limit antibiotic use in poultry production and recent international marketing agreements that prohibit treating poultry with antibiotics have limited the disease-fighting tools available to poultry and livestock producers, particularly in Europe. There is a need to evaluate potential antibiotic alternatives to improve both production and disease resistance in high-intensity food animal production. Nutritional approaches to counteract the debilitating effects of stress and infection may provide producers with useful alternatives to antibiotics. Improving disease resistance in food animals, particularly in the absence of antibiotic treatment, is a key strategy in the effort to increase food safety. ARS research has demonstrated the efficacy of several nutritional immunomodulators, including vitamin D3 and yeast cell wall products, to protect against bacterial infection due to stress and challenge with opportunistic pathogens. These studies also provide an animal model for testing the efficacy of nutritional strategies that may affect the response to stress and related infection in humans
Heat and mass transfer on MHD flow through a porous medium over a stretching surface with heat source
An attempt has been made to study the heat and mass transfer effect on the flow over a stretching sheet in the presence of a heat source. The novelty of the present study is to consider the span wise variation of magnetic field strength, heat source and heat flux. It is also considered the effect of viscous dissipation. The method of solution involves similarity transformation which leads to an exact solution of velocity field. The coupled non-linear and non homogeneous heat equation has been solved by applying Kummer’s function. The non-homogeneity of the heat equation is contributed by the consideration of viscous dissipative energy. KYEWORDS: Heat source, Viscous dissipation, Porous medium, Kummer’s function
Critical Evaluation of Bacteriophage to Prevent and Treat Colibacillosis in Poultry
There is a continuing need to find alternatives to antibiotics in animal and human medicine. Bacteriophages are viruses that infect and kill bacteria, with no known activity to plant and animal cells. We have conducted research to critically evaluate the efficacy of bacteriophage to both prevent and treat colibacillosis in poultry. Bacteriophages lytic to an Escherichia coli pathogenic to poultry were isolated from municipal waste water treatment plants and poultry processing plants. Two bacteriophage isolates were selected to use in studies designed to determine the efficacy of these bacteriophage to prevent and treat severe colibacillosis in poultry. Colibacillosis was induced by injecting 6 X 104 cfu of E. coli into the thoracic airsac when the birds were 1 week of age. Initial studies demonstrated that mortality was significantly reduced when the challenge culture was mixed with bacteriophage prior to challenging the birds. In subsequent studies, we have shown that an aerosol spray of bacteriophage given to the birds prior to this E. coli challenge can prevent the disease, and that an intramuscular injection of bacteriophage provides an effective treatment of this disease. We have demonstrated that bacteriophage can be used to both prevent and treat colibacillosis in poultry and may provide an effective alternative to antibiotic use in animal and human medicine
Molecular characterization of senescence marker protein-30 gene promoter: Identification of repressor elements and functional nuclear factor binding sites
<p>Abstract</p> <p>Background</p> <p>Senescence marker protein-30 (SMP30), whose expression declines during aging in rat liver, has been proposed as an important aging marker. Besides apoptosis, SMP30 also protects cells against various other injuries by enhancement of membrane calcium-pump activity. The mechanism of this differential gene expression mechanism is not known. DNA-protein interactions, mutation analysis and luciferase reporter assay studies have been performed to elucidate the mechanism of transcriptional regulation of SMP30 gene.</p> <p>Results</p> <p>We have characterized up to -2750 bp of the promoter by DNA-protein interactions studies. Twenty eight transcription factor binding sites have been identified by DNase I footprinting and electrophoretic mobility shift assay (EMSA). Transient transfection of 5' and 3' -deleted promoter-reporter constructs and luciferase assay illustrated the region between -128/+157 bp is sufficient to drive promoter activity. We have mapped an essential regulatory region between -513 to -352 bp which causes a drastic decline of reporter activity. This region contains CdxA, GATA2 and SRY transcription factor binding sites. Individual mutation of these three sites showed increase in reporter activity. Mutation in SRY site (-403/-368) showed maximum increase in reporter activity among these three sites. Therefore, we suggest that SRY like protein may be acting as a strong repressor of SMP30 gene along with CdxA and GATA-2. We also report that mutation of both Sp1 (172/-148 bp) and a C/EBPβ (-190/-177 bp) transcription binding site located adjacent to each other on SMP30 gene promoter, causes a significant enhancement in reporter activity than individual mutation, thus may be causing the repression of SMP30 promoter activity.</p> <p>Conclusion</p> <p>These studies provide novel insights into the mechanism that regulate SMP30 gene expression.</p
Rotational Bands and Electromagnetic Transitions of some even-even Neodymium Nuclei in J-Projected Hartree-Fock Model
Rotational structures of even-even Nd nuclei are studied with the
self-consistent deformed Hartree-Fock (HF) and angular momentum (J) projection
model. Spectra of ground band, recently observed , and a few
more excited, positive and negative parity bands have been studied upto high
spin values. Apart from these detailed electromagnetic properties (like E2, M1
matrix elements) of all the bands have been obtained. There is substantial
agreement between our model calculations and available experimental data.
Predictions are made about the band structures and electromagnetic properties
of these nuclei. Some 4-qasiparticle K-isomeric bands and their electromagnetic
properties are predicted.Comment: 20 page
New limit for the half-life of double beta decay of Zr to the first excited state of Mo
Neutrinoless Double Beta Decay is a phenomenon of fundamental interest in
particle physics. The decay rates of double beta decay transitions to the
excited states can provide input for Nuclear Transition Matrix Element
calculations for the relevant two neutrino double beta decay process. It can be
useful as supplementary information for the calculation of Nuclear Transition
Matrix Element for the neutrinoless double beta decay process. In the present
work, double beta decay of Zr to the excited state of
Mo at 871.1 keV is studied using a low background 230 cm HPGe
detector. No evidence of this decay was found with a 232 g.y exposure of
natural Zirconium. The lower half-life limit obtained for the double beta decay
of to the excited state of is y at 90% C.L., an improvement by a factor of
4 over the existing experimental limit at 90\% C.L. The sensitivity is
estimated to be y at 90% C.L. using
the Feldman-Cousins method.Comment: 11 pages, 7 figures, Accepted in Eur. Phys. J.
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