372 research outputs found
Effect of Noble Element Alloying on Passivity and Passivity Breakdown of Ni
Welding of stainless steels can generate welding fumes containing carcinogenic hexavalent chromium (Cr^+6). To mitigate this problem, a new Ni-Cu-Pd welding consumable alloy has been developed. The addition of a small amount of Cu and Pd in Ni enhances the galvanic compatibility of Ni with stainless steels and improves its localized corrosion behavior. In this paper, the artificial pit electrode technique and X-ray photoelectron spectroscopy were used to study the benefits of Cu and Pd alloying. The passive film on Ni-10Cu-1Pd alloy mainly consisted of outer Ni-hydroxide and inner oxide, and the noble elements Pd and Cu apparently did not contribute to the formation of the passive film. However, Pd catalyzed the reduction of Cu at the bottom of artificial pits, which enhanced the cathodic reaction and thus ennobled the protection potential, making stable pit growth more difficult. This catalytic effect of Pd also prevented the propagation of deep pits in a test using a thin foil crevice sample.Financial support of the Strategic Environmental Research and Development Program (SERDP) through project WP-1415 is greatly appreciated
Identification of parental line specific effects of MLF2 on resistance to coccidiosis in chickens
<p>Abstract</p> <p>Background</p> <p><it>MLF2</it> was the candidate gene associated with coccidiosis resistance in chickens. Although single marker analysis supported the association between <it>MLF2</it> and coccidiosis resistance, causative mutation relevant to coccidiosis was not identified yet. Thus, this study suggested segregation analysis of <it>MLF2</it> haplotype and the association test of the other candidate genes using improved data transformation.</p> <p>Results</p> <p>A haplotype probably originated from one parental line was found out of 4 major haplotypes of <it>MLF2</it>. Frequency of this haplotype was 0.2 in parental chickens and its offspring in 12 families. Allele substitution effect of the <it>MLF2</it> haplotype originated from a specific line was associated with increased body weight and fecal egg count explaining coccidiosis resistance. Nevertheless Box-Cox transformation was able to improve normality; association test did not produce obvious different results compared with analysis with log transformed phenotype.</p> <p>Conclusion</p> <p>Allele substitution effect analysis and classification of <it>MLF2</it> haplotype identified the segregation of haplotype associated with coccidiosis resistance. The haplotype originated from a specific parental line was associated with improving disease resistance. Estimating effect of <it>MLF2</it> haplotype on coccidiosis resistance will provide useful information for selecting animals or lines for future study.</p
MicroRNA gga-miR-200a-3p modulates immune response via MAPK signaling pathway in chicken afflicted with necrotic enteritis
International audienceAbstractMicroRNAs (miRNAs) are small non-coding RNAs that contribute to host immune response as post-transcriptional regulation. The current study investigated the biological role of the chicken (Gallus gallus) microRNA-200a-3p (gga-miR-200a-3p), using 2 necrotic enteritis (NE) afflicted genetically disparate chicken lines, 6.3 and 7.2, as well as the mechanisms underlying the fundamental signaling pathways in chicken. The expression of gga-miR-200a-3p in the intestinal mucosal layer of NE-induced chickens, was found to be upregulated during NE infection in the disease-susceptible chicken line 7.2. To validate the target genes, we performed an overexpression analysis of gga-miR-200a-3p using chemically synthesized oligonucleotides identical to gga-miR-200a-3p, reporter gene analysis including luciferase reporter assay, and a dual fluorescence reporter assay in cultured HD11 chicken macrophage cell lines. Gga-miR-200a-3p was observed to be a direct transcriptional repressor of ZAK, MAP2K4, and TGFβ2 that are involved in mitogen-activated protein kinase (MAPK) pathway by targeting the 3′-UTR of their transcripts. Besides, gga-miR-200a-3p may indirectly affect the expression of protein kinases including p38 and ERK1/2 at both transcriptional and translational levels, suggesting that this miRNA may function as an important regulator of the MAPK signaling pathway. Proinflammatory cytokines consisting of IL-1β, IFN-γ, IL-12p40, IL-17A, and LITAF belonging to Th1 and Th17-type cytokines, were upregulated upon gga-miR-200a-3p overexpression. These findings have enhanced our knowledge of the immune function of gga-miR-200a-3p mediating the chicken immune response via regulation of the MAPK signaling pathway and indicate that this miRNA may serve as an important biomarker of diseases in domestic animals
Expression and regulation of avian beta-defensin 8 protein in immune tissues and cell lines of chickens
Objective Defensins are a large family of antimicrobial peptides and components of the innate immune system that invoke an immediate immune response against harmful pathogens. Defensins are classified into alpha-, beta-, and theta-defensins. Avian species only possess beta-defensins (AvBDs), and approximately 14 AvBDs (AvBD1–AvBD14) have been identified in chickens to date. Although substantial information is available on the conservation and phylogenetics, limited information is available on the expression and regulation of AvBD8 in chicken immune tissues and cells. Methods We examined AvBD8 protein expression in immune tissues of White Leghorn chickens (WL) by immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (RT-qPCR). In addition, we examined AvBD8 expression in chicken T-, B-, macrophage-, and fibroblast-cell lines and its regulation in these cells after lipopolysaccharide (LPS) treatment by immunocytochemistry and RT-qPCR. Results Our results showed that chicken AvBD8 protein was strongly expressed in the WL intestine and in macrophages. AvBD8 gene expression was highly upregulated in macrophages treated with different LPS concentrations compared with that in T- and B-cell lines in a time-independent manner. Moreover, chicken AvBD8 strongly interacted with other AvBDs and with other antimicrobial peptides as determined by bioinformatics. Conclusion Our study provides the expression and regulation of chicken AvBD8 protein in immune tissues and cells, which play crucial role in the innate immunity
B -> Xs l_i^+ l_j^+ Decays with R-parity Violation
We derive the upper bounds on certain products of R-parity- and
lepton-flavor-violating couplings from B \ra X_s {l_i}^+ {l_j}^- decays.
These modes of B-meson decays can constrain the product combinations of the
couplings with one or more heavy generation indices which are comparable with
or stronger than the present bounds. From the studies of the invariant dilepton
mass spectrum and the forward backward asymmetry of the emitted leptons we note
the possibility of detecting R-parity-violating signals even when the total
decay rate due to R-parity violating couplings is comparable with that in the
standard model and discriminating two types of R-parity-violating signals. The
general expectation of the enhancement of the forward backward asymmetry of the
emitted leptons in the minimal supersymmetric standard model with R-parity may
be corrupted by R-parity violation.Comment: 10 pages, Revtex, 1 table and 2 figure
Worldvolume Uncertainty Relations for D-Branes
By quantizing an open string ending on a D-brane in a nontrivial supergravity
background, we argue that there is a new kind of uncertainty relation on a
D-brane worldvolume. Furthermore, we fix the form of the uncertainty relations
and their dependence on the string coupling constant by requiring them to be
consistent with various string theory and M theory dualities. In this way we
find a web of uncertainties of spacetime for all kinds of brane probes,
including fundamental strings, D-branes of all dimensions as well as M theory
membranes and fivebranes.Comment: 19 pages, minor modification on p.
A superconducting tensor detector for mid-frequency gravitational waves: its multi-channel nature and main astrophysical targets
Mid-frequency band gravitational-wave detectors will be complementary for the
existing Earth-based detectors (sensitive above 10 Hz or so) and the future
space-based detectors such as LISA, which will be sensitive below around 10
mHz. A ground-based superconducting omnidirectional gravitational radiation
observatory (SOGRO) has recently been proposed along with several design
variations for the frequency band of 0.1 to 10 Hz. For three conceptual designs
of SOGRO (e.g., pSOGRO, SOGRO and aSOGRO), we examine their multi-channel
natures, sensitivities and science cases. One of the key characteristics of the
SOGRO concept is its six detection channels. The response functions of each
channel are calculated for all possible gravitational wave polarizations
including scalar and vector modes. Combining these response functions, we also
confirm the omnidirectional nature of SOGRO. Hence, even a single SOGRO
detector will be able to determine the position of a source and polarizations
of gravitational waves, if detected. Taking into account SOGRO's sensitivity
and technical requirements, two main targets are most plausible: gravitational
waves from compact binaries and stochastic backgrounds. Based on assumptions we
consider in this work, detection rates for intermediate-mass binary black holes
(in the mass range of hundreds up to ) are expected to be
. In order to detect stochastic gravitational
wave background, multiple detectors are required. Two aSOGRO detector networks
may be able to put limits on the stochastic background beyond the indirect
limit from cosmological observations.Comment: 35 pages, 8 figures, 4 table
Twisted Bundles on Noncommutative and D-brane Bound States
We construct twisted quantum bundles and adjoint sections on noncommutative
, and investigate relevant D-brane bound states with non-Abelian
backgrounds. We also show that the noncommutative with non-Abelian
backgrounds exhibits SO duality and via this duality we get a Morita
equivalent on which only D0-branes exist. For a reducible non-Abelian
background, the moduli space of D-brane bound states in Type II string theory
takes the form .Comment: 19 pages, Latex. v2: Title is changed. Minor corrections. A reference
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MicroRNA expression profiling in the lungs of genetically different Ri chicken lines against the highly pathogenic avian influenza H5N1 virus
The highly pathogenic avian influenza (HPAI) virus triggers infectious diseases, resulting in pulmonary damage and high mortality in domestic poultry worldwide. This study aimed to analyze miRNA expression profiles after infection with the HPAI H5N1 virus in resistant and susceptible lines of Ri chickens.For this purpose, resistant and susceptible lines of Vietnamese Ri chicken were used based on the A/G allele of Mx and BF2 genes. These genes are responsible for innate antiviral activity and were selected to determine differentially expressed (DE) miRNAs in HPAI-infected chicken lines using small RNA sequencing. A total of 44 miRNAs were DE after 3 days of infection with the H5N1 virus. Computational program analysis indicated the candidate target genes for DE miRNAs to possess significant functions related to cytokines, chemokines, MAPK signaling pathway, ErBb signaling pathway, and Wnt signaling pathway. Several DE miRNA-mRNA matches were suggested to play crucial roles in mediating immune functions against viral evasion. These results revealed the potential regulatory roles of miRNAs in the immune response of the two Ri chicken lines against HPAI H5N1 virus infection in the lungs
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