756 research outputs found

    Adipose Tissue as an Endocrine Organ

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    As one of the largest endocrine organs in the body, adipose tissue secrets a number of bioactive hormones, called adipokines. The expression and secretion of adipokines are tightly controlled and coordinated by physiological and pathophysiological conditions. In multiple physiological conditions, such as obesity, cold adaptation, exercise training, expression and secretion of adipokines are altered accordingly, which in turn modulate the metabolism of the whole body in endocrine, paracrine and autocrine manners. The varied changes in adipose tissues are pivotal mediators that aid the body to adapt to various physiological and pathological conditions, whereas almost all obesity-associated diseases are attributable to dysregulation of adipokines

    Study on heat integration of supercritical coal-fired power plant with post-combustion COâ‚‚ capture process through process simulation

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    Coal-fired power plant (CFPP) is one of the main sources of anthropogenic COâ‚‚ emissions. Capturing COâ‚‚ from CFPP by post-combustion process plays an important role to mitigate COâ‚‚ emissions. However, a significant thermal efficiency drop was observed when integrating CFPP with post-combustion carbon capture (PCC) process due to the steam extraction for capture solvent regeneration. Thus research efforts are required to decrease this energy penalty. In this study, a steady state model for 600 MWe supercritical CFPP was developed as a reference case with a low heating value (LHV) based efficiency of 41.6%. A steady state model for MEA-based PCC process was also developed and scaled up to match the capacity of the CFPP. COâ‚‚ compression process was simulated to give an accurate prediction of its electricity consumption and cooling requirement. Different integration cases were set up according to different positions of steam extraction from the CFPP. The results show that the efficiency penalty is 12.29% and 14.9% when steam was extracted at 3.64 bar and at 9.1 bar respectively. Obvious improvements were achieved by utilizing waste heat from COâ‚‚ capture and compression process, taking part of low pressure cylinders out of service, and adding an auxiliary turbine to decompress the extracted steam. The efficiency penalty of the best case decreases to 9.75%. This study indicates that comprehensive heat integrations can significantly improve the overall energy efficiency when the CFPP is integrated with PCC and compression process

    The Paradoxical Effects of COVID-19 Event Strength on Employee Turnover Intention

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    As a global pandemic, the novel coronavirus (COVID-19) has brought enormous challenges to employees and organizations. Although numerous existing studies have highlighted that the COVID-19 pandemic is a stressful event and empirically proved its detrimental effect on employee turnover intention, few scholars have noted that this pandemic can deteriorate the external economic and employment environment simultaneously, which may further complicate employees’ intentions to leave or stay in the current organization. Drawing on event system theory and social cognitive theory, this study aims to uncover two potential cognitive mechanisms of the complex impact of COVID-19 event strength on employee turnover intention. To examine the proposed model, this study employed a three-wave and time-lagged research design and collected data from a sample of 432 employees of four Chinese companies from different industries. The findings indicated that COVID-19 event strength was negatively related to perceived external employability, and ultimately curbed employee turnover intention. Yet, COVID-19 event strength also negatively predicted perceived organizational growth, thus influencing employees to exhibit intentions to quit. Moreover, organizational identification not only attenuated the positive effect of perceived external employability on turnover intention but also amplified the negative impact of perceived organizational growth on turnover intention. Further, organizational identification moderated the indirect effects of COVID-19 event strength on turnover intention through perceived external employability and perceived organizational growth. This study provided a comprehensive insight into scholars’ understanding of the COVID-19 downstream outcomes

    Pharmacological isolation of postsynaptic currents mediated by NR2A- and NR2B-containing NMDA receptors in the anterior cingulate cortex

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    NMDA receptors (NMDARs) are involved in excitatory synaptic transmission and plasticity associated with a variety of brain functions, from memory formation to chronic pain. Subunit-selective antagonists for NMDARs provide powerful tools to dissect NMDAR functions in neuronal activities. Recently developed antagonist for NR2A-containing receptors, NVP-AAM007, triggered debates on its selectivity and involvement of the NMDAR subunits in bi-directional synaptic plasticity. Here, we re-examined the pharmacological properties of NMDARs in the anterior cingulate cortex (ACC) using NVP-AAM007 as well as ifenprodil, a selective antagonist for NR2B-containing NMDARs. By alternating sequence of drug application and examining different concentrations of NVP-AAM007, we found that the presence of NVP-AAM007 did not significantly affect the effect of ifenprodil on NMDAR-mediated EPSCs. These results suggest that NVP-AAM007 shows great preference for NR2A subunit and could be used as a selective antagonist for NR2A-containing NMDARs in the ACC

    Reliable RANSAC Using a Novel Preprocessing Model

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    Geometric assumption and verification with RANSAC has become a crucial step for corresponding to local features due to its wide applications in biomedical feature analysis and vision computing. However, conventional RANSAC is very time-consuming due to redundant sampling times, especially dealing with the case of numerous matching pairs. This paper presents a novel preprocessing model to explore a reduced set with reliable correspondences from initial matching dataset. Both geometric model generation and verification are carried out on this reduced set, which leads to considerable speedups. Afterwards, this paper proposes a reliable RANSAC framework using preprocessing model, which was implemented and verified using Harris and SIFT features, respectively. Compared with traditional RANSAC, experimental results show that our method is more efficient

    The Association Between AURKA Gene rs2273535 Polymorphism and Gastric Cancer Risk in a Chinese Population

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    The Aurora kinase A (AURKA) gene is frequently amplified and overexpressed in gastric cancer (GC). The overexpression of AURKA promotes inflammation and tumorigenesis in GC. We performed co-expression analysis to identify genes associated with AURKA and speculated its function through the COXPRESdb and STRING databases. We also conducted a hospital-based case-control study involving 385 GC cases and 470 controls in a Chinese population to evaluate the role of AURKA gene rs2273535 polymorphism in the risk of GC. Genotyping was performed using a custom-by-design 48-Plex single nucleotide polymorphism (SNP) Scanâ„¢ Kit. Co-expression analysis indicated that the overexpression of AURKA may be associated with poor prognosis of GC. In addition, TT genotypes of rs2273535 polymorphism increased the risk of GC by 72% compared to the AA genotypes. This significant correlation was also observed in the allelic and dominant models. The stratified analysis suggested that TT+AT genotypes showed positive correlation with the risk of GC among female, age <55 years group and non-smokers compared to AA genotypes. In conclusion, AURKA plays an important role in the development of GC. Larger studies with more diverse ethnic populations are needed to confirm these results

    Substrate specificity provides insights into the sugar donor recognition mechanism of O-GlcNAc transferase (OGT).

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    O-Linked β-N-acetylglucosaminyl transferase (OGT) plays an important role in the glycosylation of proteins, which is involved in various cellular events. In human, three isoforms of OGT (short OGT [sOGT]; mitochondrial OGT [mOGT]; and nucleocytoplasmic OGT [ncOGT]) share the same catalytic domain, implying that they might adopt a similar catalytic mechanism, including sugar donor recognition. In this work, the sugar-nucleotide tolerance of sOGT was investigated. Among a series of uridine 5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc) analogs tested using the casein kinase II (CKII) peptide as the sugar acceptor, four compounds could be used by sOGT, including UDP-6-deoxy-GlcNAc, UDP-GlcNPr, UDP-6-deoxy-GalNAc and UDP-4-deoxy-GlcNAc. Determined values of Km showed that the substitution of the N-acyl group, deoxy modification of C6/C4-OH or epimerization of C4-OH of the GlcNAc in UDP-GlcNAc decreased its affinity to sOGT. A molecular docking study combined with site-directed mutagenesis indicated that the backbone carbonyl oxygen of Leu653 and the hydroxyl group of Thr560 in sOGT contributed to the recognition of the sugar moiety via hydrogen bonds. The close vicinity between Met501 and the N-acyl group of GlcNPr, as well as the hydrophobic environment near Met501, were responsible for the selective binding of UDP-GlcNPr. These findings illustrate the interaction of OGT and sugar nucleotide donor, providing insights into the OGT catalytic mechanism

    Safety and Efficacy of Anti-PD-1 Monoclonal Antibodies in Patients With Relapsed or Refractory Lymphoma: A Meta-Analysis of Prospective Clinic Trails

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    Background: Immune checkpoint inhibition therapy with monoclonal antibody against programmed cell death protein 1 (PD-1), including nivolumab and pembrolizumab, has demonstrated powerful clinical efficacy in the treatment of advanced cancers. However, there is no evidence-based systematic review on the safety and efficacy of anti-PD-1 antibody in treating lymphoma.Methods: To evaluate the safety and efficacy of nivolumab/pembrolizumab, we analyzed clinical trials from PUBMED, EMBASE, and The Cochrane Library. For safety analysis, the incidence and exhibition of any grade and grade ≥3 adverse events (AEs) were evaluated. Overall response rate (ORR), 6-month progression-free survival (PFS) and 6-month overall survival (OS) were calculated for efficacy analysis.Results: Overall ten studies and 718 patients (114 non-Hodgkin lymphomas, 604 Hodgkin lymphomas) were enrolled, including 4 phase I studies and 6 phase II studies. The pooled incidences of any grade and grade ≥3 adverse events (AEs) were 74 and 24%, respectively. Drug-related deaths occurred in two patients. The most common any grade AEs were fatigue (14.91%), rash (14.8%), hypothyroidism (13.77%), platelet count decreased (13.54%), pyrexia (13%). The most common grade ≥3 AEs were neutropenia (4.79%), pneumonitis (3.58%), rash (3.38%), and leukopenia (3.31%). Fatigue (p = 0.0072) and rash (p = 0.0078) in any grade AEs were less observed in patients treated with pembrolizumab than nivolumab. The pooled ORR, PFS rate and OS rate were 58, 73, and 96%, respectively. The ORR in patients with Hodgkin lymphomas (HL) was higher than patients with non-Hodgkin lymphomas (NHL) (69.08 vs. 30.77%, p < 0.0001). However, there was no significant difference of efficacy between nivolumab and pembrolizumab.Conclusions: Nivolumab and pembrolizumab have promising outcomes with tolerable AEs and drug-related deaths in patients with relapsed or refractory lymphoma. Pembrolizumab caused less any grade AEs like fatigue and rash than nivolumab. Patients with HL got better response than NHL
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