Melt-Mixing by Novel Pitched-Tip Kneading Disks in a Co-Rotating Twin-Screw Extruder

Melt-mixing in twin-screw extruders is a key process in the development of polymer composites. Quantifying the mixing performance of kneading elements based on their internal physical processes is a challenging problem. We discuss melt-mixing by novel kneading elements called "pitched-tip kneading disk (ptKD)". The disk-stagger angle and tip angle are the main geometric parameters of the ptKDs. We investigated four typical arrangements of the ptKDs, which are forward and backward disk-staggers combined with forward and backward tips. Numerical simulations under a certain feed rate and screw revolution speed were performed, and the mixing process was investigated using Lagrangian statistics. It was found that the four types had different mixing characteristics, and their mixing processes were explained by the coupling effect of drag flow with the disk staggering and pitched-tip and pressure flows, which are controlled by operational conditions. The use of a pitched-tip effectively to controls the balance of the pressurization and mixing ability

Down regulation by a low-zinc diet in gene expression of rat prostatic thymidylate synthase and thymidine kinase

<p>Abstract</p> <p>Background</p> <p>Zinc has a wide spectrum of biological activities and its deficiency is related to various abnormalities of cell metabolism.</p> <p>Methods</p> <p>Wistar male rats, at age of 4 weeks, were fed a low-zinc diet for six weeks. The levels of bromodeoxyuridine incorporated into the prostatic DNA and the mRNA expression levels of prostate thymidylate synthase and thymidine kinase were examined.</p> <p>Result</p> <p>The low-zinc diet caused a marked reduction in the body growth and organ weights, resulted in a low hematopoiesis, hypo-albuminemia and hypocholesterolemia. Although there were few differences in plasma biochemical markers, plasma levels of luteinizing hormone and testosterone were reduced by the low-zinc diet. Bromodeoxyuridine-immunoreactive (S-phase) cells and mRNA expression levels of thymidylate synthase and thymidine kinase in the prostate cells were markedly affected by the low-zinc diet.</p> <p>Conclusion</p> <p>A low-zinc diet appears to reduce the body growth and organ weights including prostate, causing low plasma levels of luteinizing hormone and testosterone and reduction in prostate DNA replication in growing-rats.</p

Association of Blood Pressure and Body Mass Index with Intraocular Pressure in Middle-aged and Older Japanese Residents:A Cross-sectional and Longitudinal Study

To clarify whether high blood pressure (BP) and high body mass index (BMI) are associated with elevated intraocular pressure (IOP), a cross-sectional and longitudinal study was conducted. This epidemiological study analyzed health examination data obtained between 2001 and 2005 from 896 Japanese individuals (aged 32-79 years) who had not undergone any ocular surgery or medical treatment for hypertension, ocular hypertension, or glaucoma. Multiple-regression analysis of our cross-sectional data showed that systolic and diastolic BP (SBP and DBP) and BMI had significant and near-significant positive associations with IOP in men (p＜0.05) and women (p＜0.1). Our longitudinal study from analyses of covariance found that the adjusted mean level of changes in IOP tended to increase with increased levels of SBP, DBP, and BMI in men (p＜0.1). In women also, changes in SBP and BMI tended to be positively related with that of IOP (p＜0.1). The results of this study suggested that BP and BMI were positively associated with IOP in middle-aged and older Japanese. Therefore, management of BP and improvement of obesity might be especially important to Japanese patients with open-angle glaucoma or ocular hypertension as they have a higher incidence of normal-tension glaucoma than Europeans and Americans