Wear Behavior of Thermal Spray Coatings on Rotavator Blades

A rotavator is a motorized cultivator, popularly used to decrease the total time and human efforts in soil preparation. However, under dynamic loading, rotavator blades are subjected to extreme abrasive wear. The objective of this study was to enhance the working life of the rotavator blade in order to decrease the idle time required to reinstate the blade periodically during cultivation. The objective was carried out by means of thermal spray coatings, where the effect of the coatings on the extent of wear and the wear characteristics of the rotavator blades were examined. Three different detonation gun sprayed coatings, namely WC-Co-Cr, Cr₃C₂NiCr and Stellite-21 were compared in this study on high tensile steel rotavator blades. The wear rates of Cr₃C₂NiCr and Stellite-21 coated blades showed significant superiority over the uncoated blade, but not as much as shown by WC-Co-Cr coated blade.     

Emerging Insights on the Diverse Roles of Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) in Chronic Liver Diseases: Cholesterol Metabolism and Beyond

Chronic liver diseases are commonly associated with dysregulated cholesterol metabolism. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease of the proprotein convertase family that is mainly synthetized and secreted by the liver, and represents one of the key regulators of circulating low-density lipoprotein (LDL) cholesterol levels. Its ability to bind and induce LDL-receptor degradation, in particular in the liver, increases circulating LDL-cholesterol levels in the blood. Hence, inhibition of PCSK9 has become a very potent tool for the treatment of hypercholesterolemia. Besides PCSK9 limiting entry of LDL-derived cholesterol, affecting multiple cholesterol-related functions in cells, more recent studies have associated PCSK9 with various other cellular processes, including inflammation, fatty acid metabolism, cancerogenesis and visceral adiposity. It is increasingly becoming evident that additional roles for PCSK9 beyond cholesterol homeostasis are crucial for liver physiology in health and disease, often contributing to pathophysiology. This review will summarize studies analyzing circulating and hepatic PCSK9 levels in patients with chronic liver diseases. The factors affecting PCSK9 levels in the circulation and in hepatocytes, clinically relevant studies and the pathophysiological role of PCSK9 in chronic liver injury are discussed.     

Linking Late Endosomal Cholesterol with Cancer Progression and Anticancer Drug Resistance

Cancer cells undergo drastic metabolic adaptions to cover increased bioenergetic needs, contributing to resistance to therapies. This includes a higher demand for cholesterol, which often coincides with elevated cholesterol uptake from low-density lipoproteins (LDL) and overexpression of the LDL receptor in many cancers. This implies the need for cancer cells to accommodate an increased delivery of LDL along the endocytic pathway to late endosomes/lysosomes (LE/Lys), providing a rapid and effective distribution of LDL-derived cholesterol from LE/Lys to other organelles for cholesterol to foster cancer growth and spread. LDL-cholesterol exported from LE/Lys is facilitated by Niemann–Pick Type C1/2 (NPC1/2) proteins, members of the steroidogenic acute regulatory-related lipid transfer domain (StARD) and oxysterol-binding protein (OSBP) families. In addition, lysosomal membrane proteins, small Rab GTPases as well as scaffolding proteins, including annexin A6 (AnxA6), contribute to regulating cholesterol egress from LE/Lys. Here, we summarize current knowledge that links upregulated activity and expression of cholesterol transporters and related proteins in LE/Lys with cancer growth, progression and treatment outcomes. Several mechanisms on how cellular distribution of LDL-derived cholesterol from LE/Lys influences cancer cell behavior are reviewed, some of those providing opportunities for treatment strategies to reduce cancer progression and anticancer drug resistance.     

Local expression of transgene encoded TNF alpha in islets prevents autoimmune diabetes in nonobese diabetic (NOD) mice by preventing the development of auto-reactive islet-specific T cells

Lately, TNF alpha has been the focus of studies of autoimmunity; its role in the progression of autoimmune diabetes is, however, still unclear. To analyze the effects of TNF alpha in insulin-dependent diabetes mellitus (IDDM), we have generated nonobese diabetic (NOD) transgenic mice expressing TNF alpha under the control of the rat insulin II promoter (RIP). In transgenic mice, TNF alpha expression on the islets resulted in massive insulitis, composed of CD4+ T cells, CD8+ T cells, and B cells. Despite infiltration of considerable number of lymphoid cells in islets, expression of TNF alpha protected NOD mice from IDDM. To determine the mechanism of TNF alpha action, splenic cells from control NOD and RIP-TNF alpha mice were adoptively transferred to NOD-SCID recipients. In contrast to the induction of diabetes by splenic cells from control NOD mice, splenic cells from RIP-TNF alpha transgenic mice did not induce diabetes in NOD-SCID recipients. Diabetes was induced however, in the RIP-TNF alpha transgenic mice when CD8+ diabetogenic cloned T cells or splenic cells from diabetic NOD mice were adoptively transferred to these mice. Furthermore, expression of TNF alpha in islets also downregulated splenic cell responses to autoantigens. These data establish a mechanism of TNF alpha action and provide evidence that local expression of TNF alpha protects NOD mice from autoimmune diabetes by preventing the development of autoreactive islet-specific T cells.     

Consumer satisfaction and perceived quality: Complementary or divergent constructs?

Conflicting models exist in the literature of the process through which perceived quality and/or satisfaction affect behavioral intentions. Further, virtually no theoretical framework has been explicitly developed to help combine perceived quality models with satisfaction models. This article applies a theoretical framework to help build a model that attempts to explain the relationships among disconfirmation of expectations, perceived quality, satisfaction, perceived situational control, and behavioral intentions. The study compares the ability of two models to help explain the relationship among these variables. The results of the study suggest that the focal and contextual dimensions of disconfirmation of expectations affect perceived quality enroute to their influence on behavioral intentions. Additionally, the results indicate that perceived quality affects satisfaction and behavioral intentions are affected by satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

HEAT TRANSFER BETWEEN HORIZONTAL TUBES AND FREEBOARD REGION OF A LOW-RANK COAL FLUIDIZED BED COMBUSTOR

Experiments are conducted to measure the heat transfer rates to air-cooled horizontal tubes of diameter 38.1mm in the freeboard region of a pilot-scale fluidized-bed combustor burning North Dakota lignite- Silica sand with diameter ranging from 883 to 973 μim is used as bed material. The tests are carried out without limestone addition and ash recycle, at average bed temperatures ranging from 698 to 1117K, freeboard temperatures of 700 to 1139 K and superficial velocities of 1.74 to 1.86 m/s. Among the existing correlations, those proposed by George and Grace (1982), and Byam et al. (1981) are found to predict the experimental results quite well and their root-mean-square deviations are found to be 15.8 and 18.4 percent respectively. @KEYWORDS: Heat transfer, Fluidized bed Coal combustor     

Factors affecting women's knowledge of antenatal serum screening

Antenatal screening for fetal anomaly is offered routinely in Glasgow. This study assessed pregnant women's knowledge of the test and implications of results. Questionnaires were completed by 574 women. Knowledge of the nature and uses of the test was superior to earlier studies Two-thirds knew that screening was undertaken for Down's syndrome, and 81% for spina bifida. The majority were aware of the sample used, ages invited and gestation at which it was undertaken. Knowledge of the likely results and implications was poorer. Three-quarters were unaware that 10% of results would suggest an increased risk. Half did not realise that positive results could occur without fetal abnormality, or negative results could be falsely reassuring. Socioeconomic deprivation was associated with poorer knowledge but not lower uptake. Written information was associated with superior knowledge and higher uptake. Leaflets should be provided prior to booking, at which time resultant queries can be answered.     

Inhibition of TNF alpha improves survival in an experimental model of acute pancreatitis

The best method for the diagnosis of osteoporosis and assessment of fracture risk is currently considered to be bone densitometry. The most commonly used dual-energy X-ray absorptiometry (DXA) methods may sometimes not predict bone mass accurately in every skeletal site, are expensive and not widely available. The recent development of computed analysis of a plain radiograph of the hand might provide a practical, inexpensive and rapid method for evaluation of bone mineral status. In this study we evaluated 20 healthy premenopausal and 660 postmenopausal women. In 36 of these subjects a second evaluation was carried out after 2 years of therapy with calcium supplements. The internal and external diameters of the second metacarpal and the metacarpal and ultradistal radial bone density were evaluated using a technical device developed in our laboratory and marketed by NIM, Verona, Italy (Osteoradiometer). The radiographic images, captured by a video camera, were digitized and studied by computed analysis. In 150 subjects bone density at the level of the lumbar spine, femur, and ultradistal and proximal radius was also measured by DXA techniques. Both external (D) and internal (d) diameters increase significantly with age and years since menopause (YSM), whereas metacarpal index (D--d/D) and metacarpal and ultradistal radial bone density decrease significantly with age and YSM. The ratio between metacarpal bone mineral content and the cortical area (volumetric metacarpal bone density) did not change with age. Significant correlations were found between radiometric findings and DXA measurements. The best correlation coefficients were between bone density measured at the level of the ultradistal radius by DXA and radiographic absorptiometry. In the 2-year follow-up study, a 4.9% and 6.2% decline in radial metacarpal bone density respectively were observed, but the difference was statistically significant only for the latter. In conclusion, computed radiogrammetry is closely correlated with all DXA measurements and may be useful in screening of large populations, providing a simple, inexpensive and sufficiently precise method for evaluation of bone mineral status. Further studies are warranted for assessing the accuracy of radiogrammetry for longitudinal investigations and its capacity to predict fracture risk.