Influence of Prewhirl Regulation by Inlet Guide Vanes on Cavitation Performance of a Centrifugal Pump

The influence of prewhirl regulation by inlet guide vanes (IGVs) on a centrifugal pump performance is investigated experimentally and numerically. The experimental results show that IGVs can obviously change the head and increase the efficiency of the tested centrifugal pump over a wide range of flow rates. Although the cavitation performance is degraded, the variation of the cavitation critical point is less than 0.5 m. Movement of the computed three-dimensional streamlines in suction pipe and impeller are analyzed in order to reveal the mechanism how the IGVs realize the prewhirl regulation. The calculated results show that the influence of IGVs on the cavitation performance of centrifugal pump is limited by a maximum total pressure drop of 1777 Pa, about 7.6% of the total pressure at the suction pipe inlet for a prewhirl angle of 24°

Effects of advanced glycation end-products (AGEs) on skin keratinocytes by nuclear factor-kappa B (NF-κB) activation

Advance glycation end-products (AGEs) are produced in patients with long-term hyperglycemia metabolic disorder and responsible for multiple symptoms including impaired wound healing. This study was designed to reveal the roles and possible mechanism of AGE in diabetic wound healing. Sixteen Sprague-Dawley (SD) rats were divided into two groups randomly; the streptozotocin (STZ) induced diabetic group and the normal group. Eight weeks later, epidermal growth factor (EGF) and AGE levels, nuclear factor-kappa B (NF-κB) localization and cell viability were measured in vivo. Keratinocytes from normal skin were cultured in AGE-enriched conditional media, and the cell viability, apoptosis, adhesion and migration were detected in order to find the directed evidence between AGE and keratinocytes. AGE content was higher and NF-κB expression was more localized in the nuclear of keratinocytes in diabetic skins. AGE could inhibit normal cell growth by inducing apoptosis and arresting cell division cycle, inhibiting cell adhesion and promoting migration which might be mediated by NF-κB in vitro. Blocking NF-κB activity could reverse effects of AGE on cell proliferation and migration, but not adhesion. Therefore, AGE could damage the skin keratinocytes function in vivo and in vitro, and the activation of NF-κB is involved in this process.Key words: AGE, NF-kappaB, keratinocytes, diabetes, wound healing

Design Method of Controllable Blade Angle and Orthogonal Optimization of Pressure Rise for a Multiphase Pump

The hydraulic design method of controllable blade angle for rotodynamic multiphase pump with impeller and diffuser is proposed. The distribution of blade angle along the meridional streamline is governed by the normalized fourth-order and first-order polynomial function for impeller and diffuser, respectively. The orthogonal optimization method with five factors and four levels is employed by numerical simulation to optimize the geometry parameters, including the shroud angle at the leading and trailing edge βIs0, βIs1, the blade difference at inlet ∆βI0, and the coefficients at hub and shroud kh, ks. According to orthogonal analysis, the influence of each factor on pressure rise is estimated, and the optimization values of for those parameters are determined. The pressure rise of optimization multiphase pump is increased by 12.8 kPa in comparison of the base pump. Results show that the distributions of gas volume fraction (GVF) and the pressure become more uniform after optimization, which improves the transporting performance of the multiphase pump

Organoid models of gastrointestinal Neoplasms: Origin, current status and future applications in personalized medicine

The in vitro organoid model is a major technological breakthrough that has been established as an important tool in many basic biological and clinical applications. This near-physiological 3D culture system accurately models various biological processes, including tissue renewal, stem cell/niche functions and tissue responses to drugs, mutations or damage. Organoids have the potential value of being an accurate model for disease predictions or drug screening applications and to identify the ideal treatment for that patient. Carcinogenesis can be modeled by mutating specific cancer genes in wild-type organoids; and patient-derived organoids provide an important resource in the development of personalized cancer treatment. Organoids from cancer patients could be used to identify the ideal treatment for a specific patient by growing matched healthy and diseased organoids from human cancer patients which additionally enables clinical screens for drug combinations. Organoids could also provide autologous cells or—in the future—tissue for transplantation. In this review, we discuss the current advances, challenges and potential applications of this technique in gastrointestinal neoplasms. Keywords: Gastrointestinal neoplasms, Intestinal stem cells, Living biobanks, Personalized medicine, Stem cell niches, Wnt signalin

An Overview of Foreign Long-Range Precise Air Striking Development

Long-range air striking is an important trend in the modern air operations. This paper focuses on the development of equipment, technology, and operation concepts in long-range air strike domain in foreign countries, analyzes the main research status in this field and summarizes the development trends in operation concepts, weapon platforms, and kill chains. Three typical operation modes of long-range air striking, which are collaborative target detection guided long-range striking, collaborative target indication guided long-range striking and networked relayed guided long-range striking, are proposed from the perspective of how guidance information is generated. Based on the development situation in foreign countries, key technologies supporting long-range air striking are summarized and discussed

Effect of Virtual Mass Force on the Mixed Transport Process in a Multiphase Rotodynamic Pump

To explore the effect of virtual mass force, the unsteady two-phase flow in a multiphase rotodynamic pump impeller was numerically simulated, where the inlet gas void fraction was 4.9%, 14.9%, and 25.2%, respectively. The drag force and the virtual mass force were accounted for and the cases with and without the latter one were both analyzed for comparison. The results show that the trajectories of the gas bubbles are influenced by the virtual mass force evidently in the inlet extended region. Due to the effect of virtual mass force, some gas will firstly move to the shroud before accumulating in the hub region of the impeller. The characteristic of the pump head was discussed and the results demonstrate that the virtual mass force can decrease the pump head and lead to its fluctuation. In addition, the comparison between the steady and unsteady simulation shows that the virtual mass effect can be found only by unsteady simulation