7,451 research outputs found
Classification of equivariant real vector bundles over a circle
This is a continuation of the authors' previous work [math.AT/9910001] on
classification of equivariant complex vector bundles over a circle. In this
paper we classify equivariant real vector bundles over a circle with a compact
Lie group action, by characterizing the fiber representations of them, and by
using the result of the complex case. We also treat the triviality of them. The
basic phenomenon is similar to the complex case but more complicated here.Comment: 16 pages, AMS-LaTeX v1.
Classification of Equivariant Complex Vector Bundles over a Circle
In this paper we characterize the fiber representations of equivariant
complex vector bundles over a circle and classify these bundles. We also treat
the triviality of equivariant complex vector bundles over a circle by
investigating the extensions of representations. As a corollary of our results,
we calculate the reduced equivariant K-group of a circle for any compact Lie
group.Comment: 15 pages, AMS-LaTeX v1.
Renal Podocyte Injury in a Rat Model of Type 2 Diabetes Is Prevented by Metformin
Hyperglycemia promotes oxidative stress and hence generation of reactive oxygen species (ROS), which is known to play a crucial role in the pathogenesis of diabetic nephropathy. Metformin, an oral hypoglycemic drug, possesses antioxidant effects. The aim of this paper is to investigate the protective effects of metformin on the injury of renal podocytes in spontaneously diabetic Torii (SDT) rats, a new model for nonobese type 2 diabetes. Metformin (350 mg/kg/day) was given to SDT rats for 17 weeks. Blood glucose, glycated haemoglobin (HbA1c), and albuminuria were examined. Kidney histopathology, renal 8-hydroxydeoxyguanosine (8-OHdG) levels and apoptosis were examined. In 43-week-old SDT rats, severe hyperglycemia was developed, and albuminuria was markedly increased. Diabetes induced significant alterations in renal glomerular structure. In addition, urinary and renal 8-OHdG levels were highly increased, and podocyte loss was shown through application of the TUNEL and synaptopodin staining. However, treatment of SDT rats with metformin restored all these renal changes. Our data suggested that diabetes-induced podocyte loss in diabetic nephropathy could be suppressed by the antidiabetes drug, metformin, through the repression of oxidative injury
Periodontitis-induced systemic inflammation exacerbates atherosclerosis partly via endothelial-mesenchymal transition in mice.
Growing evidence suggests close associations between periodontitis and atherosclerosis. To further understand the pathological relationships of these associations, we developed periodontitis with ligature placement around maxillary molars or ligature placement in conjunction with Porphyromonas gingivalis lipopolysaccharide injection at the ligature sites (ligature/P.g. LPS) in Apolipoprotein E knock out mice and studied the atherogenesis process in these animals. The mice were fed with high fat diet for 11 weeks and sacrificed for analyzing periodontitis, systemic inflammation, and atherosclerosis. Controls did not develop periodontitis or systemic inflammation and had minimal lipid deposition in the aortas, but mice receiving ligature or ligature/P.g. LPS showed severe periodontitis, systemic inflammation, and aortic plaque formation. The aortic plaque contained abundant macrophages and cells expressing both endothelial and mesenchymal cell markers. The severity of periodontitis was slightly higher in mice receiving ligature/P.g. LPS than ligature alone, and the magnitude of systemic inflammation and aortic plaque formation were also notably greater in the mice with ligature/P.g. LPS. These observations indicate that the development of atherosclerosis is due to systemic inflammation caused by severe periodontitis. In vitro, P.g. LPS enhanced the secretion of pro-inflammatory cytokines from macrophages and increased the adhesion of monocytes to endothelial cells by upregulating the expression of adhesion molecules from endothelial cells. Moreover, secretory proteins, such as TNF-α, from macrophages induced endothelial-mesenchymal transitions of the endothelial cells. Taken together, systemic inflammation induced by severe periodontitis might exacerbate atherosclerosis via, in part, causing aberrant functions of vascular endothelial cells and the activation of macrophages in mice
Meteorin regulates mesendoderm development by enhancing nodal expression
During gastrulation, distinct lineage specification into three germ layers, the mesoderm, endoderm and ectoderm, occurs through an elaborate harmony between signaling molecules along the embryonic proximo-distal and anterior-posterior axes, and Nodal signaling plays a key role in the early embryonic development governing embryonic axis formation, mesoderm and endoderm specification, and left-right asymmetry determination. However, the mechanism by which Nodal expression is regulated is largely unknown. Here, we show that Meteorin regulates Nodal expression and is required for mesendoderm development. It is highly expressed in the inner cell mass of blastocysts and further in the epiblast and extra-embryonic ectoderm during gastrulation. Genetic ablation of the Meteorin gene resulted in early embryonic lethality, presumably due to impaired lineage allocation and subsequent cell accumulation. Embryoid body culture using Meteorin-null embryonic stem (ES) cells showed reduced Nodal expression and concomitant impairment of mesendoderm specification. Meteorin-null embryos displayed reduced levels of Nodal transcripts before the gastrulation stage, and impaired expression of Goosecoid, a definitive endoderm marker, during gastrulation, while the proximo-distal and anterior-posterior axes and primitive streak formation were preserved. Our results show that Meteorin is a novel regulator of Nodal transcription and is required to maintain sufficient Nodal levels for endoderm formation, thereby providing new insights in the regulation of mesendoderm allocation.open1113sciescopu
Identifying packet droppers in sensor networks via report analysis
In an unattended sensor network, sensor nodes can be compromised. Based on compromised nodes, the adversary can launch various attacks and packet dropping is one of the easiest attacks. Many schemes have been proposed to mitigate the packet dropping attack, but few can effectively and efficiently identify the droppers. In this thesis, we propose a simple yet effective scheme to identify packet droppers. This scheme only requires sending and forwarding nodes to report their observations to the base station, and the base station can analyze the reports, identify inconsistencies in the reports, and then locate the droppers. All nodes are organized into a tree rooted at the base station and each node is required to report the number of packets it has received as well as the number and the composition of packets forwarded by its parent node on the tree, which it has overheard. Using rules we propose, the base station can analyze the received reports to check if there is inconsistency among the reports; if some inconsistencies are found, the base station can further infer the identities of packet droppers. The scheme can also tolerate erroneous reports, natural packet dropping and so on. A mark-based scheme is also proposed to identify packet dropper or modifier. Extensive simulations have been conducted to demonstrate the effectiveness of the scheme
Legislative History of the Special Adoption Act (Legislative History) (2012) (Korea)
In order to focus adoption procedures on the welfare of the child, national supervision must be strengthened, and a policy must be established around the basic paradigm that the best protection of a child is for the child to be raised by his/her birth family and in his/her birth country
Special Adoption Act (2012) (Korea)
The purpose of this Act is to set forth the necessary requirements and procedures of adopting a child in need of protection, and other matters necessary to support such adoptions, which are all aimed at promoting the rights and welfare of the adopted child
Severe ARDS caused by adenovirus: early initiation of ECMO plus continuous renal replacement therapy
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