1,759 research outputs found
Geochemical Constrains on Nature of Source Region of The Late Permian Emeishan Continental Flood Basalts, SW China
Abstract in http://www.lpi.usra.edu/meetings/gold2001/pdf/3488.pd
Autotaxin signaling facilitates β cell dedifferentiation and dysfunction induced by Sirtuin 3 deficiency
OBJECTIVE: β cell dedifferentiation may underlie the reversible reduction in pancreatic β cell mass and function in type 2 diabetes (T2D). We previously reported that β cell-specific Sirt3 knockout (Sirt3f/f;Cre/+) mice developed impaired glucose tolerance and glucose-stimulated insulin secretion after feeding with high fat diet (HFD). RNA sequencing showed that Sirt3-deficient islets had enhanced expression of Enpp2 (Autotaxin, or ATX), a secreted lysophospholipase which produces lysophosphatidic acid (LPA). Here, we hypothesized that activation of the ATX/LPA pathway contributed to pancreatic β cell dedifferentiation in Sirt3-deficient β cells. METHODS: We applied LPA, or lysophosphatidylcoline (LPC), the substrate of ATX for producing LPA, to MIN6 cell line and mouse islets with altered Sirt3 expression to investigate the effect of LPA on β cell dedifferentiation and its underlying mechanisms. To examine the pathological effects of ATX/LPA pathway, we injected the β cell selective adeno-associated virus (AAV-Atx-shRNA) or negative control AAV-scramble in Sirt3f/f and Sirt3f/f;Cre/+ mice followed by 6-week of HFD feeding. RESULTS: In Sirt3f/f;Cre/+ mouse islets and Sirt3 knockdown MIN6 cells, ATX upregulation led to increased LPC with increased production of LPA. The latter not only induced reversible dedifferentiation in MIN6 cells and mouse islets, but also reduced glucose-stimulated insulin secretion from islets. In MIN6 cells, LPA induced phosphorylation of JNK/p38 MAPK which was accompanied by β cell dedifferentiation. The latter was suppressed by inhibitors of LPA receptor, JNK, and p38 MAPK. Importantly, inhibiting ATX in vivo improved insulin secretion and reduced β cell dedifferentiation in HFD-fed Sirt3f/f;Cre/+ mice. CONCLUSIONS: Sirt3 prevents β cell dedifferentiation by inhibiting ATX expression and upregulation of LPA. These findings support a long-range signaling effect of Sirt3 which modulates the ATX-LPA pathway to reverse β cell dysfunction associated with glucolipotoxicity
Late Permian rifting of the South China Craton caused by the Emeishan mantle plume?
Stratigraphic relationships and bulk-rock geochemical data indicate that Upper Permian metabasalts in the Songpan-Ganzi and Yidun terranes, on the eastern margin of the Tibetan Plateau, are part of the Emeishan large igneous province, which is believed to have formed from the Emeishan mantle plume. Eruption of the Emeishan basalts at 260 Ma was coincident with rifting of the western margin of the South China Craton to form the Songpan-Ganzi ocean basin. The spatial and temporal coincidence between basalt eruption and continental rifting, as well as regional doming prior to eruption, suggest that continental break-up was a response to the Late Permian Emeishan plume. The Songpan-Ganzi ocean basin was rapidly filled with Triassic flysch deposits, then deformed and uplifted during Mesozoic collision between the North China and South China Blocks and the Tertiary collision of India and Eurasia.published_or_final_versio
Preparation and analysis of a new bioorganic metallic material
Biofouling on metal surfaces is one of the main reasons for increased ship drag. Many methods have already been used to reduce or remove it with moderate success. In this study, a synthetic peptide has been utilized to react with 304 stainless steel aiming to generate a bioorganic stainless steel using a facile technique. After the reaction, white matter was found on the surface of the treated stainless steel via SEM, whilst the nontreated stainless steel had none. Elemental analysis confirmed that excessive N existed on the surface of the treated samples using an integrated SEM-EDS instrument, implying the presence of peptides binding on the surface of the bioorganic stainless steel. The FTIR spectra showed amide A and II peaks on the surface of the bioorganic stainless steel suggesting that either the peptides grafted onto the steel surface or the polypeptide composition accumulated on the steel samples. XPS analysis of the treated steel demonstrated that there was nitrogen bonding on the surface and it was a chemical bond via a previously unreported chemical interaction. The treated steel has a markedly increased contact angle (water contact angle of 65.7 ± 4.7° for nontreated steel in comparison to treated, 96.4 ± 2.1°), which supported the observation of the wettability change of the surface, i.e. the decrease of the surface energy value after peptide treatment. The changes of the surface parameters (such as, Sa, Sq, Ssk and Sku) of the treated steel by surface analysis were observed
Superconductivity in iron telluride thin films under tensile stress
By realizing in thin films a tensile stress state, superconductivity of 13 K
was introduced into FeTe, an non-superconducting parent compound of the iron
pnictides and chalcogenides, with transition temperature higher than that of
its superconducting isostructural counterpart FeSe. For these tensile stressed
films, the superconductivity is accompanied by the softening of the first-order
magnetic and structural phase transition; and also, the in-plane extension and
out-of-plane contraction are universal in all FeTe films independent of sign of
lattice mismatch, either positive or negative. Moreover, the correlations were
found exist between the transition temperatures and the tetrahedra bond angles
in these thin films.Comment: 4 pages, 4 figures, accepted by Physical Review Letter
Lumbar spinal stenosis: an update on the epidemiology, diagnosis and treatment
Lumbar spinal stenosis (LSS) is a common spinal disorder in the older population, and the clinical syndrome consisting of pain in the buttock or lower extremity, with or without low back pain and corresponding imaging findings of narrowing of spaces around neural and vascular elements in the lumbar spine. The diagnosis depends on history, symptoms, physical examination, radiographies. Varieties of non-operative and operative options are available for LSS patients. In this article, an update on the epidemiology, diagnosis and treatment of LSS was reviewed.published_or_final_versio
Editorial : design, implementation, and evaluation of wireless sensor network systems
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The Shapes of Cooperatively Rearranging Regions in Glass Forming Liquids
The shapes of cooperatively rearranging regions in glassy liquids change from
being compact at low temperatures to fractal or ``stringy'' as the dynamical
crossover temperature from activated to collisional transport is approached
from below. We present a quantitative microscopic treatment of this change of
morphology within the framework of the random first order transition theory of
glasses. We predict a correlation of the ratio of the dynamical crossover
temperature to the laboratory glass transition temperature, and the heat
capacity discontinuity at the glass transition, Delta C_p. The predicted
correlation agrees with experimental results for the 21 materials compiled by
Novikov and Sokolov.Comment: 9 pages, 6 figure
Solutions of Several Coupled Discrete Models in terms of Lame Polynomials of Order One and Two
Coupled discrete models abound in several areas of physics. Here we provide
an extensive set of exact quasiperiodic solutions of a number of coupled
discrete models in terms of Lame polynomials of order one and two. Some of the
models discussed are (i) coupled Salerno model, (ii) coupled Ablowitz-Ladik
model, (iii) coupled saturated discrete nonlinear Schrodinger equation, (iv)
coupled phi4 model, and (v) coupled phi6 model. Furthermore, we show that most
of these coupled models in fact also possess an even broader class of exact
solutions.Comment: 31 pages, to appear in Pramana (Journal of Physics) 201
食管癌原發灶與淋巴結轉移灶細胞染色體變化特征的比較
BACKGROUND & OBJECTIVE: Local lymph node and blood metastasis could occur at early stage of esophageal squamous cell carcinoma (ESCC), which may be the key factors of its recurrence and poor prognosis. However, the mechanism of ESCC metastasis is unclear. This study was to analyze the genetic changes in primary lesion and lymph node metastases of ESCC, to screen for and locate ESCC metastasis-related genes. METHODS: Genomic alterations in 15 pairs of primary lesions and matched metastatic lymph nodes of ESCC were analyzed by comparative genomic hybridization (CGH). RESULTS: In the 15 pairs of tissues, the most common chromosomal alterations were the gains of 3q, 8q, 6p, 20p, 5p, 18p, 2p, 2q and 1q, and the losses of 10p, 10q, 17p, 18q, 4p and 13q. Of these changes, the most significant finding was the gain of 6p with a frequency of 47% in metastatic lymph nodes and 13% in primary lesions, and the gain of 20p with a frequency of 73% in metastatic lymph nodes and 33% in primary lesions. The second interesting finding was the loss of 10p with a frequency of 53% in metastatic lymph nodes and 13% in primary lesions, and the loss of 10q with a frequency of 47% in metastatic lymph nodes and 13% in primary lesions. CONCLUSION: The gains of 6p and 20p and the losses of 10p and 10q are common genomic alterations in primary lesion and lymph node metastases of ESCC, which may code ESCC metastasis-related genes.背景與目的:食管癌早期可發生局部淋巴或血行轉移,這是導致復發和預后差的主要原因。但是,食管癌轉移發生的分子機制尚不清楚。本研究旨在分析食管癌原發灶和淋巴結轉移灶腫瘤細胞染色體變化的特征,尋找或定位與食管癌轉移相關基因,加深對其轉移機制的了解。方法:應用比較基因組雜交技術(comparativegenomichybridization,CGH)分析15例食管癌患者原發灶和其對應的淋巴結轉移灶的染色體基因組改變。結果:最常見染色體DNA拷貝數增加的部位是3q,8q,6p,20p,5p,18p,2p,2q,1q;常見的染色體DNA拷貝數丟失的部位是10p,10q,17p,18q,4p,13q。其中,最有意義的發現是6p增加(原發灶:2/15,13%,轉移灶:7/15,47%),20p增加(原發灶:5/15,33.3%,轉移灶:11/15,73.3%)。第二個發現是10p丟失(原發灶:2/15,13.3%,轉移灶:8/15,53%),10q丟失(原發灶:2/15,13.3%,轉移灶:7/15,46.6%)。結論:食管癌原發灶和淋巴結轉移灶細胞染色體基因組改變最顯著的部位是6p,20p的增加和10p,10q的丟失;這些部位可能存在與食管癌細胞淋巴結轉移相關的基因。link_to_subscribed_fulltex
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