Simulation of heat transfer on the peristaltic flow of a Jeffrey-six constant fluid in a diverging tube

Peristaltic flow of a Jeffrey-six constant fluid in a nonuniform tube is investigated under the assumption of long wavelength and low Reynolds number approximations. The dimensionless quantities are used to simplify momentum and energy equations assuming that fluid physical/rheological properties remain constant. Regular perturbation method is invoked to find an analytical solution for the velocity and temperature field. The variation of pressure rise and frictional forces with the different parameters is also examined numerically. Results are also presented graphically at the end of the article.     

Dynamic modeling of a gas pressure control system for a gas‐assisted injection molding process

This study presents the development of dynamic models for gas injection pressure that may be implemented in the design of control systems for gas‐injection units. A nonlinear dynamic model was first derived and then verified by experimental measurements. This was done by using a laboratory‐built, gas‐assisted injection unit. The agreement between the prediction and measurement indicates that the present nonlinear dynamic model adequately predicts the dynamic behavior of gas injection pressure during the process. Although the resulting model is useful for understanding the behavior of the process and the effects of different process variables, its complexity may cause difficulties in a real control application. Therefore, a second‐order model based on the basic characteristics of the nonlinear model was proposed to approximate the gas injection pressure. In order to determine the model parameters, the algorithm of recursive least‐square system identification was employed. A comparison of simulated results of an identified model with experimental data showed that the model accurately predicted the transient behavior of gas injection pressure. Consequently, this low‐order model can be easily implemented into the control system design of a gas‐injection unit.     

A clinical technique for temporization of teeth to receive porcelain laminate veneers

Temporization of teeth prepared for porcelain laminate veneers is sometimes necessary to preserve occlusal relationships, prevent sensitivity or maintain esthetics. The literature describes several techniques which satisfy different requirements for temporization. A modified technique is presented that satisfies at once: occlusion, sensitivity and esthetic needs. Clinical time spent with the patient is minimized by fabricating a matrix on a diagnostic cast prior to the preparation/ impression appointment.     

Peer interaction and learning with computers in small groups

While anecdotal reports of computer use in classrooms suggest that students often work together, few studies have focused on the interaction between students or on its consequences for achievement. This paper reviews the research on peer interaction with computers to determine its effects on learning. The purposes of this review are to determine (a) the advantages or disadvantages of group work for learning, (b) the kinds of verbal interaction that occur when students work together at the computer, and (c) the kinds of interaction that are beneficial or detrimental for learning. This paper considers the possible cognitive and socioemotional processes that mediate the effects of peer interaction on learning, and discusses the implications of the research findings for the design of computer software.     

2-Azetidinone cholesterol absorption inhibitors: structure-activity relationships on the heterocyclic nucleus

A series of azetidinone cholesterol absorption inhibitors related to SCH 48461 ((-)-6) has been prepared, and compounds were evaluated for their ability to inhibit hepatic cholesteryl ester formation in a cholesterol-fed hamster model. Although originally designed as acyl CoA: cholesterol acyltransferase (ACAT) inhibitors, comparison of in vivo potency with in vitro activity in a microsomal ACAT assay indicates no correlation between activity in these two models. The molecular mechanism by which these compounds inhibit cholesterol absorption is unknown. Despite this limitation, examination of the in vivo activity of a range of compounds has revealed clear structure-activity relationships consistent with a well-defined molecular target. The details of these structure-activity relationships and their implications on the nature of the putative pharmacophore are discussed.     

SOLVENT EXTRACTION OF PAKISTAN COALS (III) EXTRACTION AND CHARACTERIZATION OF THE EXTRACTS BY SPECTROSCOPIC TECHNIQUES

The Makerwal coal of Pakistan gives higher extractibi1ity with Tetrahydrofuran ( THF ) as compared to Sharigh, Sor-Range and Lakhra coals. The structural characterization of Pakistan coal extracts by FT-IR spectroscopy indicates that all the extracts contained less condensed aromatic rings in comparision to their original coal.     

Characterizing alcohol dependence: Transitions during young and middle adulthood.

Community and high-risk sample studies suggest that alcohol dependence is relatively stable and chronic. By contrast, epidemiological studies demonstrate a strong age-graded decline whereby alcohol dependence tends to peak in early adulthood and declines thereafter. The authors identified the latent trajectory structure of past-year alcohol dependence to investigate (a) whether the syndrome is characterized by symptom profiles and (b) the extent to which the syndrome is stable and persistent. Data from current drinkers (N = 4,003) in the National Longitudinal Survey of Youth were analyzed across two waves: 1989 (ages 24-32 years) and 1994 (ages 29-37 years). Three classes of alcohol dependence were observed; symptom endorsement probabilities increased across successively severe classes. Latent transition analyses showed high rates of stability, supporting alcohol dependence as a relatively chronic condition. Although there was evidence of progression to more severe dependence, there was greater syndrome remission. Trajectory classes and transition probabilities were generalizable across race and sex and, to a lesser extent, age cohort and family history of alcoholism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fear of psychological treatment and its relation to mental health service avoidance.

We evaluated whether a measure of mental health treatment fearfulness is associated with past mental health treatment history and/or current treatment status. Student Ss who either were or were not about to begin psychotherapy responded to the fear measure and a measure of psychological distress, and they also answered questions about their mental health treatment-seeking history. Analysis indicated that increased treatment fearfulness was associated retrospectively with a history of service underconsumption and cross-sectionally with a nonclinical treatment status. We conclude that treatment fears are associated with treatment-seeking decisions and suggest that future studies focus on delineating the causal relation of these variables and on the role that treatment fears may play in treatment compliance and behavior change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

IL-10 regulates liver pathology in acute murine Schistosomiasis mansoni but is not required for immune down-modulation of chronic disease

We have used IL-10 gene knockout mice (IL-10T) to examine the role of endogenous IL-10 in the down-modulation of hepatic granuloma formation and lymphocyte responses that occurs in chronic infection with the helminth parasite Schistosoma mansoni. Although IL-10-deficient animals showed 20 to 30% mortality between 8 and 14 wk postinfection, they displayed no alterations in their susceptibility to infection and produced similar numbers of eggs as their wild-type littermates. The IL-10T mice displayed a significant increase in hepatic granuloma size at the acute stage of infection, which was associated with increased IFN-gamma, IL-2, IL-1beta, and TNF-alpha mRNA expression in liver and elevated Th1-type cytokine production by lymphoid cells. Despite developing an enhanced Th1-type cytokine response, the IL-10T mice showed no consistent decrease in their Th2-type cytokine profile. Surprisingly, although granulomatous inflammation was enhanced at the acute stage of infection, the livers of IL-10T mice displayed no significant increase in fibrosis and underwent normal immune down-modulation at the chronic stage of infection. Moreover, the down-modulated state could be induced in IL-10T mice by sensitizing the animals to schistosome eggs before infection, further demonstrating that the major down-regulatory mechanism is not dependent upon IL-10. We conclude that while IL-10 plays an important role in controlling acute granulomatous inflammation, it plays no essential role in the process of immune down-modulation in chronic schistosome infection.     

Evaluation of boys with marked breast development at puberty

OBJECTIVE: The purpose of this study was to investigate the efficiency of second-trimester maternal serum screening for Down's syndrome and open neural tube defects using alpha-fetoprotein and free beta-human chorionic gonadotropin as serum markers. METHODS: 3, 188 women underwent testing between 14th and 22nd week of pregnancy. Of all tested patients, 25.4% were >/=35 years old. A cut-off risk of >/=1:250 for Down's syndrome and MS-AFP >/=2.0 MoM for open neural tube defect were considered screen-positive. RESULTS: The detection rate for Down's syndrome was 77.8% (7/9) with 8.2% screen-positive rate (7.9% false-positive rate). When evaluated separately, in patients younger than 35 and in those >/=35 years old, the screen-positive rates were 3.1 and 23.3%, respectively. A total of 52 (1.6%) were found screen-positive for open neural tube defect; 2 cases of encephalocela and 1 case of gastroschisis were confirmed prenatally. CONCLUSION: The respectable number of cases with trisomy 21 identified in this study confirms that routine mid-trimester screening for Down's syndrome including MS-AFP, free beta-hCG and maternal age is useful in identifying pregnancies at increased risk.