9,670 research outputs found
Early-stage star forming cloud cores in GLIMPSE Extended Green Objects (EGOs) as traced by organic species
In order to investigate the physical and chemical properties of massive star
forming cores in early stages, we analyse the excitation and abundance of four
organic species, CH3OH, CH3OCH3, HCOOCH3 and CH3CH2CN, toward 29 Extended Green
Object (EGO) cloud cores that were observed by our previous single dish
spectral line survey. The EGO cloud cores are found to have similar methanol
J_3-J_2 rotation temperatures of ~44 K, a typical linear size of ~0.036 pc, and
a typical beam averaged methanol abundance of several 10^(-9) (the beam
corrected value could reach several 10^(-7)). The abundances of the latter
three species, normalized by that of methanol, are found to be correlated also
across a large variety of clouds such as EGO cloud cores, hot corinos, massive
hot cores and Galactic Center clouds. The chemical properties of the EGO cloud
cores lie between that of hot cores and hot corinos. However, the abundances
and abundance ratios of the four species can not be satisfactorily explained by
recent chemical models either among the EGO cloud cores or among the various
types of cloud cores from literature
New constructions of signed difference sets
Signed difference sets have interesting applications in communications and
coding theory. A -difference set in a finite group of order
is a subset of with distinct elements such that the expressions
for all distinct two elements , represent each non-identity
element in exactly times. A -signed difference set
is a generalization of a -difference set , which satisfies
all properties of , but has a sign for each element in . We will show
some new existence results for signed difference sets by using partial
difference sets, product methods, and cyclotomic classes
State Consensus Analysis and Design for High-Order Discrete-Time Linear Multiagent Systems
The paper deals with the state consensus problem of high-order discrete-time linear multiagent systems (DLMASs) with fixed information topologies. We consider three aspects of the consensus analysis and design problem: (1) the convergence criteria of global state consensus, (2) the calculation of the state consensus function, and (3) the determination of the weighted matrix and the feedback gain matrix in the consensus protocol. We solve the consensus problem by proposing a linear transformation to translate it into a partial stability problem. Based on the approach, we obtain necessary and sufficient criteria in terms of Schur stability of matrices and present an analytical expression of the state consensus function. We also propose a design process to determine the feedback gain matrix in the consensus protocol. Finally, we extend the state consensus to the formation control. The results are explained by several numerical examples
Rapid glycation with D-ribose induces globular amyloid-like aggregations of BSA with high cytotoxicity to SH-SY5Y cells
<p>Abstract</p> <p>Background</p> <p>D-ribose in cells and human serum participates in glycation of proteins resulting in advanced glycation end products (AGEs) that affect cell metabolism and induce cell death. However, the mechanism by which D-ribose-glycated proteins induce cell death is still unclear.</p> <p>Results</p> <p>Here, we incubated D-ribose with bovine serum albumin (BSA) and observed changes in the intensity of fluorescence at 410 nm and 425 nm to monitor the formation of D-ribose-glycated BSA. Comparing glycation of BSA with xylose (a control for furanose), glucose and fructose (controls for pyranose), the rate of glycation with D-ribose was the most rapid. Protein intrinsic fluorescence (335 nm), Nitroblue tetrazolium (NBT) assays and Western blotting with anti-AGEs showed that glycation of BSA incubated with D-ribose occurred faster than for the other reducing sugars. Protein intrinsic fluorescence showed marked conformational changes when BSA was incubated with D-ribose. Importantly, observations with atomic force microscopy showed that D-ribose-glycated BSA appeared in globular polymers. Furthermore, a fluorescent assay with Thioflavin T (ThT) showed a remarkable increase in fluorescence at 485 nm in the presence of D-ribose-glycated BSA. However, ThT fluorescence did not show the same marked increase in the presence of xylose or glucose. This suggests that glycation with D-ribose induced BSA to aggregate into globular amyloid-like deposits. As observed by Hoechst 33258 staining, 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and cell counting kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) activity assay, flow cytometry using Annexin V and Propidium Iodide staining and reactive oxygen species (ROS) measurements, the amyloid-like aggregation of glycated BSA induced apoptosis in the neurotypic cell line SH-SY5Y.</p> <p>Conclusion</p> <p>Glycation with D-ribose induces BSA to misfold rapidly and form globular amyloid-like aggregations which play an important role in cytotoxicity to neural cells.</p
Chinese Food Safety: A Case Study of Pig-Raising Industry
This paper introduces the Shuanghui scandal, which is affected Chinese food safety to some extend. On that base, the causes of the food safety problems in pig-raising industry in China are explained. Finally, some suggestion was presented to improve the safety in china.Keywords: Food safety; Pig-raising industry; Chinese agricultura
Induction of CCL8/MCP-2 by mycobacteria through the activation of TLR2/PI3K/Akt signaling pathway.
Pleural tuberculosis (TB), together with lymphatic TB, constitutes more than half of all extrapulmonary cases. Pleural effusions (PEs) in TB are representative of lymphocytic PEs which are dominated by T cells. However, the mechanism underlying T lymphocytes homing and accumulation in PEs is still incompletely understood. Here we performed a comparative analysis of cytokine abundance in PEs from TB patients and non-TB patients by protein array analysis and observed that MCP-2/CCL8 is highly expressed in the TB-PEs as compared to peripheral blood. Meanwhile, we observed that CCR5, the primary receptor used by MCP-2/CCL8, is mostly expressed on pleural CD4(+) T lymphocytes. Furthermore, we found that infection with either Mycobacterium bovis Bacillus Calmette-Guérin (BCG) or Mycobacterium tuberculosis H37Rv induced production of MCP-2/CCL8 at both transcriptional and protein level in Raw264.7 and THP-1 macrophage cells, mouse peritoneal macrophages as well as human PBMC monocyte-derived macrophages (MDMs). The induction of MCP-2/CCL8 by mycobacteria is dependent on the activation of TLR2/PI3K/Akt and p38 signaling pathway. We conclude that accumulation of MCP-2/CCL8 in TB-PEs may function as a biomarker for TB diagnosis
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