37 research outputs found

    Simulation of droplet impacting a square solid obstacle in microchannel with different wettability by using high density ratio pseudopotential multiplerelaxation- time (MRT) lattice Boltzmann Method (LBM)

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    In this paper, a pseudopotential high density ratio (DR) lattice Boltzmann Model was developed by incorporating multi-relaxation-time (MRT) collision matrix, large DR external force term, surface tension adjustment external force term and solid-liquid pseudopotential force. It was found that the improved model can precisely capture the two-phase interface at high DR. Besides, the effects of initial Reynolds number, Weber number, solid wall contact angle (CA), ratio of obstacle size to droplet diameter ( 1 χ ), ratio of channel width to droplet diameter ( 2 χ ) on the deformation and breakup of droplet when impacting on a square obstacle were investigated. The results showed that with the Reynolds number increasing, the droplet will fall along the obstacle and then spread along both sides of the obstacle. Besides, by increasing Weber number, the breakup of the liquid film will be delayed and the liquid film will be stretched to form an elongated ligament. With decreasing of the wettability of solid particle (CA→ 180°), the droplet will surround the obstacle and then detach from the obstacle. When 1 χ is greater than 0.5, the droplet will spread along both sides of the obstacle quickly; otherwise, the droplet will be ruptured earlier. Furthermore, when 2 χ decreases, the droplet will spread earlier and then fall along the wall more quickly; otherwise, the droplet will expand along both sides of the obstacle. Moreover, increasing the hydrophilicity of the microchannel, the droplet will impact the channel more rapidly and infiltrate the wall along the upstream and downstream simultaneously; on the contrary, the droplet will wet downstream only

    New Insights Into the Role of Follicle-Stimulating Hormone in Sex Differentiation of the Protogynous Orange-Spotted Grouper, Epinephelus coioides

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    Follicle-stimulating hormone (FSH) signaling is considered to be essential for early gametogenesis in teleosts, but its functional roles during sex differentiation are largely unknown. In this study, we investigated the effects of long-term and short-term FSH injection on sex differentiation in the protogynous orange-spotted grouper (Epinephelus coioides). Long-term FSH treatment initially promoted the formation of ovaries but subsequently induced a male fate. The expression of female pathway genes was initially increased but then decreased, whereas the expression of male pathway genes was up-regulated only during long-term FSH treatment. The genes related to the synthesis of sex steroid hormones, as well as serum 11-ketotestosterone and estradiol, were also up-regulated during long-term FSH treatment. Short-term FSH treatment activated genes in the female pathway (especially cyp19a1a) at low doses but caused inhibition at high doses. Genes in the male pathway were up-regulated by high concentrations of FSH over the short term. Finally, we found that low, but not high, concentrations of FSH treatment activated cyp19a1a promoter activities in human embryonic kidney (HEK) 293 cells. Overall, our data suggested that FSH may induce ovarian differentiation or a change to a male sex fate in the protogynous orange-spotted grouper, and that these processes occurred in an FSH concentration-dependent manner

    Distinct Roles of Estrogen Receptors in the Regulation of Vitellogenin Expression in Orange-Spotted Grouper (Epinephelus coioides)

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    During their breeding season, estrogen induces vitellogenin (VTG) production in the liver of teleost fish through estrogen receptors (ERs) that support oocyte vitellogenesis. There are at least three ER subtypes in teleost fish, but their roles in mediating E2-induced VTG expression have yet to be ascertained. In this study, we investigated the expression of vtgs and ers in the liver of orange-spotted grouper (Epinephelus coioides). Their expression levels were significantly increased in the breeding season and were upregulated by an estradiol (E2) injection in female fish, except for the expression of erβ1. The upregulation of vtgs, erα and erβ2 by E2 was also observed in primary hepatocytes, but these stimulatory effects could be abolished by ER antagonist ICI182780 treatment. Subsequent studies showed that ERβ antagonist Cyclofenil downregulated the E2-induced expression of vtg, erα, and erβ2, while the ERβ agonist DPN simulated their expression. Knockdown of erβ2 by siRNA further confirmed that ERβ2 mediated the E2-induced expression of vtgs and erα. To reveal the mechanism of ERβ2 in the regulation of erα expression, the erα promoter was cloned, and its activity was examined in cells. E2 treatment simulated the activity of the erα promoter in the presence of ERβ2. Deletions and site-directed mutations showed that the E2 up-regulated transcriptional activity of erα occurs through a classical half-estrogen response element- (ERE) dependent pathway. This study reveals the roles of ER subtypes in VTG expression in orange-spotted grouper and provides a possible explanation for the rapid and efficient VTG production in this species during the breeding season

    Duodenum-Preserving Resection of the Pancreatic Head versus Pancreaticoduodenectomy for Treatment of Chronic Pancreatitis with Enlargement of the Pancreatic Head: Systematic Review and Meta-Analysis

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    The results of this meta-analysis show that DPPHR should be established as first-line treatment because of lower level of severe early postoperative complications, maintenance of endocrine pancreatic functions, shortening of postoperative hospitalization time, and increase of quality of life compared to pancreaticoduodenectomy

    Are Internal or External Pancreatic Duct Stents the Preferred Choice for Patients Undergoing Pancreaticoduodenectomy? A Meta-Analysis

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    The technique of pancreatic duct stenting during pancreatic anastomosis can markedly reduce the incidence of postoperative pancreatic fistula (PF) after pancreaticoduodenectomy (PD). The method of drainage includes using either an external or an internal stent; the meta-analysis result shows us that there were no differences in the rates of postoperative complications between PD using internal stents and PD using external stents; internal stents may be more favorable during postoperative management of drainage tube. What is more, internal stents could reduce the digestive fluid loss and benefit the digestive function

    Clinicopathologic characteristics, laboratory parameters, treatment protocols, and outcomes of pancreatic cancer: a retrospective cohort study of 1433 patients in China

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    Objectives The prognosis of people with pancreatic cancer is extremely unfavorable. However, the prognostic factors remain largely undefined. We aimed to perform comprehensive analyses of clinicopathologic characteristics, laboratory parameters, and treatment protocols for exploring their role as prognostic factors of pancreatic cancer. Methods Patients diagnosed with pancreatic cancer and hospitalized at the China National Cancer Center between April 2006 and May 2016 were enrolled in this retrospective cohort study. Clinicopathologic characteristics, laboratory parameters, and treatment protocols were compared among patients at different stages of the disease. The association between these factors and overall survival (OS) was analyzed using the Kaplan–Meier method and Cox proportional hazards model. Results The present study included 1,433 consecutive patients with pancreatic cancer. Median OS was 10.6 months (95% confidence interval [CI] 9.8–11.3 months), with 1-, 3-, and 5-year survival rates of 43.7%, 14.8%, and 8.8%, respectively. Cox multivariate analysis findings identified the following factors as independent predictors of OS: gender (female vs male, hazard ratio 0.72, 95% CI [0.54–0.95]); elevated total bilirubin (TBil; 1.82, 1.34–2.47); elevated carbohydrate antigen 19-9 (CA19-9; 1.72, 1.17–2.54); tumor being located in pancreatic body and tail (1.52, 1.10–2.10); advanced T stage (T3-4 vs T1-2, 1.62, 1.15–2.27); lymph node metastasis (1.57, 1.20–2.07); distant metastasis (1.59, 1.12–2.27); the presence of surgical resection (0.53, 0.34–0.81); and the presence of systemic chemotherapy (0.62, 0.45–0.82). Conclusions Being male, elevated TBil and carcinoembryonic antigen, tumor being located in pancreatic body and tail, advanced T stage, lymph node and distant metastasis, the absence of surgical resection, and the absence of systematic chemotherapy were associated with worse OS in patients with pancreatic cancer
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