8,587 research outputs found

    Multiple Ca2+ signaling pathways regulate intracellular Ca 2+ activity in human cardiac fibroblasts

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    Ca2+ signaling pathways are well studied in cardiac myocytes, but not in cardiac fibroblasts. The aim of the present study is to characterize Ca2+ signaling pathways in cultured human cardiac fibroblasts using confocal scanning microscope and RT-PCR techniques. It was found that spontaneous intracellular Ca2+ (Cai 2+) oscillations were present in about 29% of human cardiac fibroblasts, and the number of cells with Cai 2+ oscillations was increased to 57.3% by application of 3% fetal bovine serum. Cai 2+ oscillations were dependent on Ca2+ entry. Cai2+ oscillations were abolished by the store-operated Ca2+ (SOC) entry channel blocker La3+, the phospholipase C inhibitor U-73122, and the inositol trisphosphate receptors (IP3Rs) inhibitor 2-aminoethoxydiphenyl borate, but not by ryanodine. The IP3R agonist thimerosal enhanced Ca2+ i oscillations. Inhibition of plasma membrane Ca2+ pump (PMCA) and Na+-Ca2+ exchanger (NCX) also suppressed Ca i 2+ oscillations. In addition, the frequency of Ca i 2+ oscillations was reduced by nifedipine, and increased by Bay K8644 in cells with spontaneous Cai 2+ oscillations. RT-PCR revealed that mRNAs for IP3R1-3, SERCA1-3, CaV1.2, NCX3, PMCA1,3,4, TRPC1,3,4,6, STIM1, and Orai1-3, were readily detectable, but not RyRs. Our results demonstrate for the first time that spontaneous Cai 2+ oscillations are present in cultured human cardiac fibroblasts and are regulated by multiple Ca2+ pathways, which are not identical to those of the well-studied contractile cardiomyocytes. This study provides a base for future investigations into how Ca2+ signals regulate biological activity in human cardiac fibroblasts and cardiac remodeling under pathological conditions. © 2009 Wiley-Liss, Inc.postprin

    C-Reactive Protein Promotes Diabetic Kidney Disease in db/db Mice via the CD32b-Smad3-mTOR signaling Pathway

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    The Effects of MALL on L2 Pronunciation Learning: A Meta-Analysis

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    Mobile-assisted language learning has emerged as a valuable tool for L2 pronunciation learning as it offers ample opportunities for learners to perform authentic learning activities anytime and anywhere. However, the extent to which mobile devices may facilitate or enhance L2 pronunciation has yet to be systematically investigated. To address the research gap, the study drew on a meta-analytic framework to examine the overall average effect of mobile devices on L2 pronunciation learning. The meta-analysis consisted of 13 primary studies featured in an experimental vs. control group design published between 2009 and 2020. These studies involved 655 participants and reported 19 effect sizes in the results. The analysis revealed a robust effect size (d =.66) as captured by a random-effects model, indicating a significant effect concerning the use of mobile devices on L2 pronunciation learning. In the meta-analysis, significant moderators were also identified, and their moderating effects were critically examined. In light of the research findings, it is argued that innovative activities and tasks using mobile devices can be adopted for both language instructors and learners due to their portability, connectivity, and individuality

    Two maternal origins of Chinese domestic light-body type goose

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    China is particularly rich in goose genetic resources. The systemic study of genetic diversity and origin of Chinese indigenous geese will provide important scientific basis for the conservation, utilization of resources and human history. The 521 bp control region (D-loop) of mitochondrial DNA from 13 lightbody type breeds was sequenced. The results showed that in the D-loop region of the 13 gray goose breeds, the content of T, C, A and G nucleotides was 23.8, 29.0, 32.2 and 15.1%, respectively. The average haplotype diversity (Hd) and nucleotide diversity (Pi) of domestic geese were 0.2153 and 0.00046, respectively. The 13 light-body type breeds had bigger nucleotide variance value among populations than the value within populations and all the breeds did not exist population expansion.Shared haplotype analysis and systemic systematic evolution analysis revealed that Chinese lightbody type domestic goose owned two maternal origins. YL goose breed originated from greylag goose (anser anser), and the other 12 light- body type goose breeds originated from swan goose (anser cygnoides)

    An invisibility cloak using silver nanowires

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    In this paper, we use the parameter retrieval method together with an analytical effective medium approach to design a well-performed invisible cloak, which is based on an empirical revised version of the reduced cloak. The designed cloak can be implemented by silver nanowires with elliptical cross-sections embedded in a polymethyl methacrylate host. This cloak is numerically proved to be robust for both the inner hidden object as well as incoming detecting waves, and is much simpler thus easier to manufacture when compared with the earlier proposed one [Nat. Photon. 1, 224 (2007)].Comment: 7 pages, 4 figures, 2 table

    CDAL: A Scalable Scheme for Digital Resource Reorganization

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    In many circumstances, including e-learning, there is a need to reorganize digital resources, scattered in many places, into a coherently accessible repository. This paper introduces a methodology to do the job efficiently. Specifically, the resources that the scheme needs to handle presents the following challenges, 1) mass, 2) various data types, 3) coming out continuously, i.e., the scheme must support incremental reorganization. 4) usually existing with its own directory structures. We describe the scheme in detail, together with considerations for trade-offs. The following features are highlighted: 1) the reorganization of scattered resources is modeled as a tree-merging process., which results in a good trade-off between efficiency and quality. 2) hierarchical storage arrangement with a uniform index at each level ensures scalability. As an application of the scheme, CDAL (Chinese Digital Assets Library) is briefed, which is a TB-scale archive of digital resources on the Web.Computer Science, Artificial IntelligenceComputer Science, Interdisciplinary ApplicationsComputer Science, Theory & MethodsSCI(E)CPCI-S(ISTP)

    Differential-phase-shift quantum key distribution using heralded narrow-band single photons

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    Intra-breath arterial oxygen oscillations detected by a fast oxygen sensor in an animal model of acute respiratory distress syndrome

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    Background There is considerable interest in oxygen partial pressure (Po2) monitoring in physiology, and in tracking PO2 changes dynamically when it varies rapidly. For example, arterial PO2 (PaO2) can vary within the respiratory cycle in cyclical atelectasis (CA), where PaO2 is thought to increase and decrease during inspiration and expiration, respectively. A sensor that detects these PaO2 oscillations could become a useful diagnostic tool of CA during acute respiratory distress syndrome (ARDS). Methods We developed a fibreoptic PO2 sensor (<200 µm diameter), suitable for human use, that has a fast response time, and can measure PO2 continuously in blood. By altering the inspired fraction of oxygen (FIO2) from 21 to 100% in four healthy animal models, we determined the linearity of the sensor's signal over a wide range of PaO2 values in vivo. We also hypothesized that the sensor could measure rapid intra-breath PaO2 oscillations in a large animal model of ARDS. Results In the healthy animal models, PaO2 responses to changes in FIO2 were in agreement with conventional intermittent blood-gas analysis (n=39) for a wide range of PaO2 values, from 10 to 73 kPa. In the animal lavage model of CA, the sensor detected PaO2 oscillations, also at clinically relevant PaO2 levels close to 9 kPa. Conclusions We conclude that these fibreoptic PaO2 sensors have the potential to become a diagnostic tool for CA in ARDS
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