bluuebunny/crossref_metadata_2025 huggingface dataset:
Streamlining of the Radial Inlet Design Process for Centrifugal Compressors
Authors: Saladino Anthony J. , Bielecki Stephen J.
Published: June 2008

A radial compressor inlet represents an asymmetric and highly complex flow path, with high potential for flow disturbance. Due to the large computational resources and long lead times required for CFD analysis of such components, this resource has historically been reserved for conceptual or prototype designs. In the production environment, where compressor internals are often customized to a particular application, designers generally rely on geometric analysis of the flowpath. Low priority historically given to centrifugal inlet design is adequately illustrated in “mud etching” of the flow field in a retrofitted radial compressor inlet. An estimate of the potential for efficiency gain through inlet optimization, based on CFD predicted loss coefficient, is presented. It is noted that poor exit flow profiles can negatively impact performance, as well. Ill effects may include efficiency loss in downstream components, mechanical vibration, and compressor control issues. With continual improvement in CFD processing speed, the prospect of applying CFD based optimization techniques to production radial inlet designs becomes more feasible. In this investigation, CFD analysis is performed on an existing radial inlet design and validated with data from a flow visualization test rig. The subject inlet design is subsequently optimized through CFD analysis, with detailed attention being given to the impact of adjusting various geometric characteristics. A number of independent geometric parameters, which are determined to have significant impact on loss coefficient, are condensed into an optimization parameter. This optimization parameter serves as a preliminary indicator of design quality. Alternative brute force design methods are time prohibitive and may not provide the designer with feedback required to effectively alter geometry. Details of the CFD modeling and subsequent validation testing of the baseline inlet design are given. CFD results for a variety of modified inlet designs are presented. An overview of the optimization parameter and its application to a new radial inlet design are also presented. The potential for such an optimization parameter to limit design iteration is illustrated. Although additional refinement is suggested, the subject optimization parameter shows potential to direct the designer away from low efficiency designs.
Log Mean Temperature Correction Factor: An Alternative Representation
Authors: Fakheri Ahmad
Published: June 2008

The Log Mean Temperature Difference (LMTD) correction factor, F, is traditionally expressed in terms of two non-dimensional parameters P=t2−t1T1−t1, and R=T1−T2t2−t1 in form of charts as the underlying equations are complicated. F shows strong functional dependence on both P and R, reducing the accuracy of reading the charts particularly in the steep regions. In this study it is shown that the LMTD correction factor F, can be expressed in terms of two new variables, φ=(T1−T2)2+(t2−t1)22[(T1+T2)−(t1+t2)] and ρ=T1−t2T2−t1. Expressed in terms of these variables, F correlations and charts are much better behaved. Furthermore, it is shown that for the shell and tube and cross flow of heat exchangers, over a wide range of operating conditions of practical interest (0.5 ≤ ρ ≤ 1.0), F can be approximated as a function of a single variable function φ, to within 4% accuracy.
Developing Guidelines for Crashworthiness of Light Rail Vehicles in Mixed Fleet Operations
Authors: Kirkpatrick Steven W. , Schroeder Martin P. , Valde´s Salazar Juan Carlos
Published: June 2008

As new passenger rail cars are introduced into existing rail fleets, the potential structural for incompatibility between cars in a collision is a safety concern. Crush damage that occurs when dissimilar strength vehicles collide is concentrated in the weaker vehicle. In a serious collision the deformation of the weaker vehicle could be sufficiently large to intrude into the occupied volume of the operator or passenger compartments. As a result, the strength incompatibility has the potential for increased risk of injury for passengers in the weaker vehicle. The design strategy of many modern rail vehicles is to reduce vehicle weight and incorporate crashworthiness design features to improve safety. This is in contrast to an older design approach where strength requirements, such as a high buff strength, were included to ensure structural integrity. The objective of this study is to assess the collision risk for a mixed rail fleet of different vehicle designs. Collision safety is investigated for three different vehicle types. The crash scenarios investigated include vehicle to vehicle collisions between newly designed cars, between older designed cars, and between a mix of new and old designs. To quantify risk, parameters such as cab crush strength, occupant volume strength, and collision speed are varied in computer crash simulations to uncover potential safety problems associated with mixed car operation. Results from these parametric analyses are presented and utilized to guide the development of new crashworthiness specifications for mixed fleet operation.
Elastic Modulus of Pb/Sn Solder Joints in Microelectronics
Authors: Basaran Cemal , Jiang Jianbin
Published: June 2008

Young’s modulus (E) values published in literature for the eutectic Pb37/Sn63 and near eutectic Pb40/Sn60 solder alloy vary significantly. One reason for this discrepancy is different testing methods for highly rate sensitive heterogeneous materials, like Pb/Sn alloys, yield different results. In this paper, we study different procedures used to obtain the elastic modulus; analytically, by single crystal elasticity and experimentally by ultrasonic testing and Nano indentation. We compare these procedures and propose a procedure for elastic modulus determination. The deformation kinetics of the Pb/Sn solder alloys is discussed at the grain size level.
On the Dynamic Short-Time Scale Wave Propagation and the Characterization of Optimal Packaging Material for High Performance Electronic Packages
Authors: Oh Yoonchan , Suh C. Steve , Sue H.-J.
Published: June 2008

The demand for higher clock speed and higher level of integration, and, at the same time, smaller die size for high-performance electronic packages has accompanied by a drastic increase in package power consumption and dissipation. Large transient thermal gradients are thus experienced upon each power-on. Unlike thermal cycling test which is usually performed to evaluate the fatigue life of solder joints, rapid thermal transient is of major concern for overall package reliability. This rapid transient at short-time scale suggests that dynamic thermal-mechanical phenomenon in packages needs to be fully understood and the associated failure mechanisms identified for improved microelectronic reliability. In this study, how rapid thermal transients affect the generation, spectral characteristics, and interference of the induced stress waves propagating in high-density packaging configurations undergoing power cycling are investigated. The short-time effects facilitated by dispersive waves in current packaging configurations are studied and the possible mechanisms behind mechanical failures including solder cracking and delamination are discussed. Knowledge base thus established enables a set of guidelines to be proposed for developing new types of polymeric underfill material. Materials hence formulated would have optimal characteristics in response to the short-time effect to effectively discourage transient wave phenomena and thus improve the overall package reliability. The presented investigation provides a better understanding of the underlying physics governing the response of a high-performance package subject to rapid thermal-mechanical transients, which could potentially be the foundation for the formulation of new molecularly designed packaging materials and the associated manufacturing processes.
Failure Simulation of Angled Polycrystalline Lines Covered With Passivation Layer
Authors: Hasegawa Masataka , Sasagawa Kazuhiko , Saka Masumi , Abe´ Hiroyuki
Published: June 2008

The atomic flux divergence due to electromigration in a passivated polycrystalline line, AFD*gen, has been formulated adding the effect of a passivation on electromigration damage to the governing parameter for electromigration damage in an unpassivated polycrystalline line, AFDgen. The parameter, AFD*gen, has been identified as a governing parameter for electromigration damage in the passivated polycrystalline line by experimental verification process. Recently, a prediction method for electromigration failure in the passivated polycrystalline line was proposed using AFD*gen, and the usefulness of the method was verified through experiment. Both the lifetime and the failure location in the passivated polycrystalline line can be predicted by means of numerical simulation of the failure process covering the building up of atomic density distribution, void initiation, void growth and ultimately—line failure. In this study, AFD*gen-based method for predicting electromigration failure is applied angled polycrystalline lines covered with passivation. There are few works on prediction of failure in the angled lines, though such lines are widely used in IC (integrated circuit) products. The failures are simulated when the corner position and its angle are changed. The dependency of lifetime and failure location on line shape is investigated.
Mechanical and Electrical Study of Linear Spring and J-Spring
Authors: Ma Lunyu , Zhu Qi , Sitaraman Suresh K.
Published: June 2008

The integrated circuit (IC) fabrication technology continues to push the limits of microelectronics packaging technologies. Today millions of transistors can be fabricated in a chip of about 1 cm × 1 cm in size, and the required I/O density is about 1600/cm2. Although tremendous advances have been made in die to substrate interconnect technologies as well as substrate/PWB technologies, these advances have not kept pace with advances in semiconductor technology, and therefore, continue to be a bottleneck for further advances in semiconductor technologies. In addition to fabrication constraints, low cost and reliability are other requirements that affect interconnect development. Wafer-level Packaging (WLP) is an effective solution to address some of these issues. A compliant interconnect, called “J-Spring”, has been proposed and developed at Georgia Institute of Technology. Although based on the same concept of inherent stress-gradient used in the linear spring, the J-Spring will provide greater in-plane compliance. These compliant interconnects can be fabricated in batch at wafer level and the pitch can be as low as 30 μm. The fine pitch can meet and exceed the requirements of International Technology Roadmap for Semiconductor (ITRS) for 2011 [ITRS, 2001] and beyond. J-Springs with different radius, angle, width, and release length have been fabricated on a test wafer. Numerical model has been created to determine the release height based on J-Spring geometry and stress gradients. Also, the compliance of J-Spring has been determined in three orthogonal directions using parametric numerical models. The compliance of J-Spring is compared with the compliance of the linear spring. The proposed compliant interconnects can accommodate the differential displacement due to CTE mismatch between the die and the substrate. In addition, to their mechanical characteristics, their electrical characteristics have been studied as well. The electrical characteristics are dependent on the geometry, dimensions and the materials used.
Deformation of Conductive Particles and Reliability of Electronic Devices Using COG
Authors: Akiguchi Takashi , Koguchi Hideo , Yamaguchi M. , Takayasu A.
Published: June 2008

Following the increasing adoption of TFT-type LCD modules in mobile and other equipment, COG (chip-on-glass) mounting is being increasingly employed instead of TCP (tape carrier package) mounting to make LCD modules smaller, thinner, and cheaper. Since the IC and LCD panel electrodes are bonded together by the conductive particles embedded in ACF (anisotropic conductive film), the bonding conditions depend substantially on the respective characteristics of the IC electrodes and the conductive particles in the ACF. We examined the effects of the arrangement, area and material properties of IC electrodes and of the profile and material properties of conductive ACF particles.
Analysis of Two-Phase Air/Water Bubbly Flow Experiment
Authors: Todd Donald R. , Hassan Yassin A. , Ortiz-Villafuerte Javier
Published: June 2008

Two different techniques, the Particle Image Velocimetry (PIV) and the Shadow-Image Velocimetry (SIV) techniques have been used to capture detailed two-phase bubbly flow experimental data. The PIV has provided a two-dimensional velocity field of the liquid phase for analysis of the continuous phase. The SIV has utilized to reconstruct the bubble shape and velocity of the dispersed phase in three-dimensions.
Experimental Estimation of the Phase Front Under Local Thermal Non-Equilibrium Condition: Phase Change Phenomena in Porous Media
Authors: Nnanna A. G. Agwu , Haji-Sheikh A. , Harris Kendall T.
Published: June 2008

A systematic experimental method of estimating the extent of the phase front under local thermal non-equilibrium condition in porous media saturated with phase change material has been developed. During phase change in porous medium, the solid matrix and the pore material are under thermodynamic non-equilibrium condition until the phase change process is complete. It is often hypothesized that the solid matrix and the pore material are in local thermal equilibrium (LTE) condition hence, the arrival of the phase front is predicted based on this hypothesis. An understanding of the rate of freezing and thawing in a porous medium undergoing the phase change process is important to permit proper implementation of procedures such as cryopreservation, cryosurgery, and to predict the thermal performance of passive cooling systems for electronic devices. In this paper, a systematic method of estimating the extent of the phase change front is developed. Results show that during the phase change process the porous medium is far from local thermal equilibrium condition.
Daily energy expenditure and cardiovascular risk in Masai, rural and urban Bantu Tanzanians
Authors: Mbalilaki J A , Masesa Z , Strømme S B , Høstmark A T , Sundquist J , Wändell P , Rosengren A , Hellenius M-L
Published: June 2008

Background

Several studies have revealed that the Masai, pastoralists in Tanzania, have low rates of coronary heart disease despite a diet high in saturated fat. It has also been suggested that they may be genetically protected. Recent studies detailing other potential protective factors, however, are lacking.

Methods

A cross-sectional investigation of 985 Tanzanian men and women (130 Masai, 371 rural Bantu and 484 urban Bantu) with mean age of 46 (9.3) years. Anthropometric measures, blood pressure, serum lipids, and the reported dietary pattern and physical activity level were assessed.

Results

82% of Masai subjects reported a high fat/low carbohydrate intake, whereas 77% of the rural Bantu subjects reported a low fat/high carbohydrate intake, while a high fat/high carbohydrate intake was the main dietary pattern of the urban Bantu group as, reported by 55%. The most conspicuous finding for the Masai was the extremely high energy expenditure, corresponding to 2565 kcal/day over basal requirements, compared with 1500 kcal/day in the rural and 891 kcal/day for the urban Bantu. Mean body mass index among the Masai was lower than the rural and urban Bantu. Mean systolic blood pressure of the Masai was also lower compared with their rural and urban Bantu counterparts. The Masai revealed a favourable lipid profile.

Conclusion

The potentially atherogenic diet among the Masai was not reflected in serum lipids and was offset probably by very high energy expenditure levels and low body weight.
Respiratory symptoms and inflammatory responses to Difflam throat-spray intervention in half-marathon runners: a randomised controlled trial
Authors: Cox A J , Gleeson M , Pyne D B , Saunders P U , Callister R , Fricker P A
Published: June 2008

Objective

In this study, the effects of Difflam Forte Anti-inflammatory Throat Spray on the incidence of upper respiratory symptoms (URS) and inflammatory responses after a half-marathon race were investigated.

Design and setting

Double-blind placebo-controlled randomised trial conducted in association with a half-marathon event.

Participants

45 well-trained half-marathon runners.

Interventions

Difflam (n = 25) or placebo (n = 20) throat sprays were self-administered three times daily for 1 week before and 2 weeks after the race.

Main outcome measures

Self-reported respiratory symptoms; plasma prostaglandin E2, myeloperoxidase, interleukin (IL) 6, IL8, IL10 and IL1 receptor antagonist (IL1ra) concentrations; and salivary myeloperoxidase and IL6 concentrations.

Results

All subjects completed the intervention without reporting any adverse events. The proportion of athletes reporting URS was not substantially different between Difflam (52%) and placebo (56%) groups (p = 0.82). However, symptom severity scores were ∼29% lower during Difflam treatment (4.7 (7.4) vs 6.6 (9.6)) AU). Post-exercise responses in plasma inflammatory markers did not differ substantially between Difflam and placebo groups. Post-race increases in salivary myeloperoxidase (∼63%; trivial to moderate difference; p = 0.13) and salivary IL6 (∼50%; trivial to moderate difference; p = 0.25) were greater in the Difflam group.

Conclusions

Prophylactic use of the Difflam reduced the severity, but not the frequency, of URS among half-marathon runners. Post-race increases in systemic inflammatory markers were not altered by Difflam use, but markers of local inflammation (salivary myeloperoxidase and IL6) were augmented in the Difflam compared with the placebo group.
Long-term effectiveness of behavioural interventions to prevent smoking among children and youth
Authors: Müller-Riemenschneider F , Bockelbrink A , Reinhold T , Rasch A , Greiner W , Willich S N
Published: June 2008

Objectives:

To evaluate the long-term effectiveness of recent behavioural interventions in the prevention of cigarette use among children and youth and to compare the effectiveness of different school-based, community-based and multisectorial intervention strategies.

Methods:

A structured search of databases and a manual search of reference lists was conducted. Randomised controlled trials published in English or German between August 2001 and August 2006 targeting youths up to 18 years of age were assessed independently by two researchers according to predefined inclusion criteria and with regard to methodological quality. Data abstraction was performed and crosschecked by two researchers. Where appropriate, pooled effect estimates were calculated and tested in sensitivity analyses.

Results:

Of 3555 articles, 35 studies met the inclusion criteria. The follow-up duration ranged from 12 months to 120 months. Although the overall effectiveness of prevention programs showed considerable heterogeneity, the majority of studies reported some positive long-term effects for behavioural smoking prevention programs. There was evidence that community-based and multisectorial interventions were effective in reducing smoking rates; in contrast, the evidence for school-based programs alone was inconclusive. Regardless of the type of intervention, the reductions observed in smoking rates were only modest.

Conclusions:

The present work identified moderate evidence for the effectiveness of behavioural interventions to prevent smoking. Although evidence for the effectiveness of school-based interventions was inconclusive, evidence for the effectiveness of community-based and multisectorial interventions was somewhat stronger. Future research should investigate the effectiveness of specific intervention components and the cost-effectiveness of interventions analysed in methodologically high-quality studies.
DO THEY SEE WHAT WE SEE?: A CRITICAL NORDIC TALE ABOUT PERCEPTIONS OF ENTREPRENEURIAL OPPORTUNITIES, GOALS AND GROWTH
Authors: BRÄNNBACK MALIN , CARSRUD ALAN
Published: June 2008

This paper serves as an overview of a decade of the authors' theoretical reviews, participant observations, empirical studies, quasi-experimental research, qualitative interviews, personal consulting, firm incubation, and action research with firms, clusters, and regional groups in both the information technology and biotechnology sectors in Finland. Interpretations of our findings are told using a narrative format, based on Nordic mythology. This story-telling approach is used to express the perceptions of entrepreneurship by various players in society. It discusses what happens when public policies are based on perceptions very different from, and in potential conflict, with those of the would-be entrepreneur. The paper addresses the current and very real problem in many Nordic countries where enormous efforts are invested in pushing technology creation assuming at the simultaneous creation of entrepreneurial high growth firms. Results show extremely low entrepreneurial activity and declining interest towards entrepreneurship as a career alternative. For those firms that do emerge growth does not seem to be the primary goal. The conclusions are discussed in terms of the long term prognosis for developing an entrepreneurial society in economically advanced nations to take advantage of the technological developments supported by governmental research funding.
Reduction of JNK1 expression with antisense oligonucleotide improves adiposity in obese mice
Authors: Yu Xing Xian , Murray Susan F. , Watts Lynnetta , Booten Sheri L. , Tokorcheck Justin , Monia Brett P. , Bhanot Sanjay
Published: June 2008

To investigate the role of JNK1 in metabolism, male ob/ ob and diet-induced obese mice were treated with a JNK1-specific antisense oligonucleotide (ASO) or control ASO at 25 mg/kg or saline twice/wk for 6 and 7 wk, respectively. JNK1 ASO reduced JNK1 mRNA and activity by 65–95% in liver and fat tissues in both models. Compared with controls, treatment with JNK1 ASO did not change food intake but lowered body weight, fat pad weight, and whole body fat content. The treatment increased metabolic rate. In addition, the treatment markedly reduced plasma cholesterol levels and improved liver steatosis and insulin sensitivity. These positive observations were accompanied by the following changes: 1) increased mRNA levels of AR-β3 and UCP1 by >60% in BAT, 2) reduced mRNA levels of ACC1, ACC2, FAS, SCD1, DGAT1, DGAT2, and RBP4 by 30–60% in WAT, and 3) reduced mRNA levels of ACC1, FAS, G-6-Pase, and PKCε by 40–70% and increased levels of UCP2 and PPARα by more than twofold in liver. JNK1 ASO-treated mice demonstrated reduced levels of pIRS-1 Ser302 and pIRS-1 Ser307 and increased levels of pAkt Ser473 in liver and fat in response to insulin. JNK1 ASO-transfected mouse hepatocytes showed decreased rates of de novo sterol and fatty acid synthesis and an increased rate of fatty acid oxidation. These results indicate that inhibition of JNK1 expression in major peripheral tissues can improve adiposity via increasing fuel combustion and decreasing lipogenesis and could therefore provide clinical benefit for the treatment of obesity and related metabolic abnormalities.
Grass carp somatolactin: I. Evidence for PACAP induction of somatolactin-α and -β gene expression via activation of pituitary PAC-I receptors
Authors: Jiang Quan , Ko Wendy K. W. , Lerner Ethan A. , Chan K. M. , Wong Anderson O. L.
Published: June 2008

Somatolactin (SL), the latest member of the growth hormone/prolactin family, is a novel pituitary hormone with diverse functions. At present, SL can be identified only in fish but not in tetrapods and its regulation at the pituitary level has not been fully characterized. Using grass carp as a model, we examined the direct effects of pituitary adenylate cyclase-activating polypeptide (PACAP) on SL secretion and synthesis at the pituitary cell level. As a first step, the structural identity of grass carp SL, SLα and SLβ, was established by 5′/3′-rapid amplification of cDNA ends. These two SL isoforms are single-copy genes and are expressed in two separate populations of pituitary cells located in the pars intermedia. In the carp pituitary, PACAP nerve fibers were detected in the nerve tracts of the neurohypophysis and extended into the vicinity of pituitary cells forming the pars intermedia. In primary cultures of grass carp pituitary cells, PACAP was effective in stimulating SL release, cellular SL content, and total SL production. The increase in SL production also occurred with parallel rises in SLα and SLβ mRNA levels. With the use of a combination of molecular and pharmacological approaches, PACAP-induced SL release and SL gene expression were shown to be mediated by pituitary PAC-I receptors. These findings, as a whole, suggest that PACAP may serve as a hypophysiotropic factor in fish stimulating SL secretion and synthesis at the pituitary level. Apparently, PACAP-induced SL production is mediated by upregulation of SLα and SLβ gene expression through activation of PAC-I receptors.
Grass carp somatolactin: II. Pharmacological study on postreceptor signaling mechanisms for PACAP-induced somatolactin-α and -β gene expression
Authors: Jiang Quan , He Mulan , Wang Xinyan , Wong Anderson O. L.
Published: June 2008

Somatolactin (SL), the latest member of the growth hormone/prolactin family, is a novel pituitary hormone with diverse functions. However, the signal transduction mechanisms responsible for SL expression are still largely unknown. Using grass carp as an animal model, we examined the direct effects of pituitary adenylate cyclase-activating polypeptide (PACAP) on SL gene expression at the pituitary level. In primary cultures of grass carp pituitary cells, SLα and SLβ mRNA levels could be elevated by PACAP via activation of PAC-I receptors. With the use of a pharmacological approach, the AC/cAMP/PKA and PLC/inositol 1,4,5-trisphosphate (IP3)/PKC pathways and subsequent activation of the Ca2+/calmodulin (CaM)/CaMK-II cascades were shown to be involved in PACAP-induced SLα mRNA expression. Apparently, the downstream Ca2+/CaM-dependent cascades were triggered by extracellular Ca2+([Ca2+]e) entry via L-type voltage-sensitive Ca2+channels (VSCC) and Ca2+release from IP3-sensitive intracellular Ca2+stores. In addition, the VSCC component could be activated by cAMP/PKA- and PLC/PKC-dependent mechanisms. Similar postreceptor signaling cascades were also observed for PACAP-induced SLβ mRNA expression, except that [Ca2+]eentry through VSCC, PKC coupling to PLC, and subsequent activation of CaMK-II were not involved. These findings, taken together, provide evidence for the first time that PACAP can induce SLα and SLβ gene expression in fish model via PAC-I receptors through differential coupling to overlapping and yet distinct signaling pathways.
Elevation in heat shock protein 72 mRNA following contractions in isolated single skeletal muscle fibers
Authors: Stary Creed M. , Walsh Brandon J. , Knapp Amy E. , Brafman David , Hogan Michael C.
Published: June 2008

The purpose of the present study was 1) to develop a stable model for measuring contraction-induced elevations in mRNA in single skeletal muscle fibers and 2) to utilize this model to investigate the response of heat shock protein 72 (HSP72) mRNA following an acute bout of fatiguing contractions. Living, intact skeletal muscle fibers were microdissected from lumbrical muscle of Xenopus laevis and either electrically stimulated for 15 min of tetanic contractions (EX; n = 26) or not stimulated to contract (REST; n = 14). The relative mean developed tension of EX fibers decreased to 29 ± 7% of initial peak tension at the stimulation end point. Following treatment, individual fibers were allowed to recover for 1 ( n = 9), 2 ( n = 8), or 4 h ( n = 9) prior to isolation of total cellular mRNA. HSP72, HSP60, and cardiac α-actin mRNA content were then assessed in individual fibers using quantitative PCR detection. Relative HSP72 mRNA content was significantly ( P < 0.05) elevated at the 2-h postcontraction time point relative to REST fibers when normalized to either HSP60 (18.5 ± 7.5-fold) or cardiac α-actin (14.7 ± 4.3-fold), although not at the 1- or 4-h time points. These data indicate that 1) extraction of RNA followed by relative quantification of mRNA of select genes in isolated single skeletal muscle fibers can be reliably performed, 2) HSP60 and cardiac α-actin are suitable endogenous normalizing genes in skeletal muscle following contractions, and 3) a significantly elevated content of HSP72 mRNA is detectable in skeletal muscle 2 h after a single bout of fatiguing contractions, despite minimal temperature changes and without influence from extracellular sources.
PGC-1α increases skeletal muscle lactate uptake by increasing the expression of MCT1 but not MCT2 or MCT4
Authors: Benton Carley R. , Yoshida Yuko , Lally James , Han Xiao-Xia , Hatta Hideo , Bonen Arend
Published: June 2008

We examined the relationship between PGC-1α protein; the monocarboxylate transporters MCT1, 2, and 4; and CD147 1) among six metabolically heterogeneous rat muscles, 2) in chronically stimulated red (RTA) and white tibialis (WTA) muscles (7 days), and 3) in RTA and WTA muscles transfected with PGC-1α-pcDNA plasmid in vivo. Among rat hindlimb muscles, there was a strong positive association between PGC-1α and MCT1 and CD147, and between MCT1 and CD147. A negative association was found between PGC-1α and MCT4, and CD147 and MCT4, while there was no relationship between PGC-1α or CD147 and MCT2. Transfecting PGC-1α-pcDNA plasmid into muscle increased PGC-1α protein (RTA +23%; WTA +25%) and induced the expression of MCT1 (RTA +16%; WTA +28%), but not MCT2 and MCT4. As a result of the PGC-1α-induced upregulation of MCT1 and its chaperone CD147 (+29%), there was a concomitant increase in the rate of lactate uptake (+20%). In chronically stimulated muscles, the following proteins were upregulated, PGC-1α in RTA (+26%) and WTA (+86%), MCT1 in RTA (+61%) and WTA (+180%), and CD147 in WTA (+106%). In contrast, MCT4 protein expression was not altered in either RTA or WTA muscles, while MCT2 protein expression was reduced in both RTA (−14%) and WTA (−10%). In these studies, whether comparing oxidative capacities among muscles or increasing their oxidative capacities by PGC-1α transfection and chronic muscle stimulation, there was a strong relationship between the expression of PGC-1α and MCT1, and PGC-1α and CD147 proteins. Thus, MCT1 and CD147 belong to the family of metabolic genes whose expression is regulated by PGC-1α in skeletal muscle.
Mechanical Stress Upregulates Intercellular Adhesion Molecule-1 in Pulmonary Epithelial Cells
Authors: Hu Xiaobo , Zhang Youyi , Cheng Deyun , Ding Yu , Yang Dongmei , Jiang Fei , Zhou Chao , Ying Binwu , Wen Fuqiang
Published: June 2008

Background: Mechanicalventilation can affect the lung, causing edema and alveolar inflammation. Intercellular adhesion molecule-1 (ICAM-1) plays an important role in this inflammatory response. Objective: The aims of this study were to investigate whether cyclic cell stretch upregulates the production of ICAM-1 by human alveolar epithelium and to explore possible mechanisms of upregulation. Methods: Human type 2-like alveolar epithelial cells (A549 cells) were exposed to cyclic tensile strain via a four-point bending system, with strains of varying frequency (0.2, 0.5, and 1 Hz), duration (0, 1, 3, and 6 h), and magnitude (500, 1,000, and 2,000 microstrain). Strain was applied at varying frequency (0.2, 0.5, 1 Hz) but at constant time (3 h) and magnitude (1,000 microstrain), at varying duration (0, 1, 3, and 6 h) but at constant frequency (0.5 Hz) and magnitude (1,000 microstrain), or at varying magnitude (500, 1,000, and 2,000 microstrain) but at constant time (3 h) and frequency (0.5 Hz). Results: Mechanical loading induced ICAM-1 protein and mRNA production in a frequency- and duration-dependent manner. At the 3-hour time point, large loadings (1,000 or 2,000 microstrain) upregulated ICAM-1 protein production, but there was no statistically significant difference between these two groups (p > 0.05). PD98059, a specific inhibitor of extracellular signal-regulated kinase (ERK), and N-acetylcysteine (NAC), an antioxidant, partially abrogated the stretch-induced ICAM-1 protein upregulation at the 3-hour loading. Conclusion: Mechanical strain can upregulate ICAM-1 production. The response is frequency and duration dependent, which may involve both ERK pathways and reactive oxidant species production.
Comparing Main and Collateral Effects of Extinction and Differential Reinforcement of Alternative Behavior
Authors: Petscher Erin Seligson , Bailey Jon S.
Published: June 2008

This study evaluated the effects and collateral effects of extinction (EXT) and differential reinforcement of alternative behavior (DRA) interventions with inappropriate vocalizations and work refusal. Both interventions have been used frequently to reduce problem behaviors. The benefits of these interventions have been established yet may be outweighed by the reported negative side effects that result. However, these collateral effects have rarely been measured or reported. DRA produced the most rapid reductions in behavior for 4 of the 5 participants. Other behaviors were measured for changes and showed that the desirable collateral effect of academic engagement tended to be higher during EXT than DRA. No evidence of EXT bursts was present with any participant, although EXT-induced aggression occurred with 1 participant.
The Exposure Hierarchy as a Measure of Progress and Efficacy in the Treatment of Social Anxiety Disorder
Authors: Katerelos Marina , Hawley Lance L. , Antony Martin M. , McCabe Randi E.
Published: June 2008

This study explored the psychometric properties and utility of the exposure hierarchy as a measure of treatment outcome for social anxiety disorder (SAD). An exposure hierarchy was created for each of 103 individuals with a diagnosis of SAD who completed a course of cognitive behavioral group therapy. Exposure hierarchy ratings were collected on a weekly basis, and a series of self-report measures were collected before and after treatment. Results indicated that the exposure hierarchy demonstrated high test-retest reliability, as well as significant convergent validity, as participants' exposure hierarchy ratings correlated positively with scores on conceptually related measures. Hierarchy ratings were significantly associated with changes in SAD symptoms over time. However, exposure hierarchy ratings were correlated to general measures of psychopathology, suggesting limited discriminant validity. The study highlights the clinical and scientific utility of the exposure hierarchy.
So Perfect It's Positively Harmful?
Authors: Glynn Owens R. , Slade Peter D.
Published: June 2008

The article by Flett and Hewitt (2006) highlights a number of important issues in the study of perfectionism and rightly urges caution against simplistic conceptualizations. Their view that the term perfectionism should be reserved for pathological forms of behavior is questionable, though understandable given the perspective from which they view it. But whatever the terminology used, the underlying processes remain unaffected. Relevance of the data they cite in support of an alleged maladaptive side to positive perfectionism, however, rests on the assumption of close parallels between self-oriented perfectionism and positive perfectionism, an assumption that may not be justified. It is important to draw attention not only to differences between the theoretical underpinnings of their and the authors perspectives but also to points of agreement that the authors may previously have failed to make clear. The authors concur entirely with their view that clear avenues of potential research are now apparent that should serve to clarify the issues.
The Effects of Fixed Ratio Values on Concurrent Mand and Play Responses
Authors: Bernstein Haven , Brown Bruce L. , Sturmey Peter
Published: June 2008

Three children diagnosed with pervasive developmental disabilities emitted a high rate of mands and a low-to-zero rate of appropriate play responses when the two responses were reinforced on concurrent Fixed Ratio 1 (FR1) schedules. When mands were reinforced on an FR10 schedule and play responses were concurrently reinforced on an FR1 schedule, play responses increased. Two participants' mands decreased from baseline levels but were maintained, and the third participant's mands increased. Implications of the use of choice procedures for clinical settings are discussed.
Exploring the Pharmacotherapeutic Options for Treating Type 2 Diabetes
Authors: Kruger Davida F.
Published: June 2008

There has been a dramatic increase in the prevalence of the most common form of diabetes, with approximately 14.6 million diagnosed and 6.2 million undiagnosed cases of type 2 (non-insulin-dependent) diabetes in the United States since 2005. If diabetes is not diagnosed early and managed properly, patients are at greater risk for microvascular and macrovascular complications, such as nerve damage, heart disease, blindness, and kidney damage. The pathogenesis of type 2 diabetes includes impaired insulin secretion, increased hepatic and muscle/fat insulin resistance, and increased glucagon secretion. Problems commonly associated with type 2 diabetes and consequent hyperglycemia are weight gain, hypertension, and dyslipidemia. The natural progression of type 2 diabetes involves increased insulin deficiency as a result of decreased beta cell function over time, which can raise glycosylated hemoglobin to dangerous levels and consequently increase the risk of death. Lifestyle modifications (eg, diet changes and increased physical activity) remain the cornerstone of early treatment, but glycemic control may worsen despite behavior changes and treatment with oral hypoglycemic agents. Historically, upon failure to maintain glucose levels with exercise and oral medication, insulin was the second-line treatment option. Current treatment algorithms include a new class of agents, incretin mimetics, such as the glucagon-like peptide-1 (GLP-1) receptor agonist exenatide. Exenatide mimics the actions of the hormone GLP-1 that occurs naturally in the gastrointestinal tract and has emerged as an efficacious therapy adjunct to 1 or more oral hypoglycemic agent(s).
Bidirectional Partner Violence Among Homeless Young Adults
Authors: Tyler Kimberly A. , Melander Lisa A. , Noel HarmoniJoie
Published: June 2008

One of the most prevalent forms of violence in contemporary society is the victimization of intimate partners. Although it has been established that homeless young people experience high levels of victimization on the street, little is known about partner violence (PV) experiences among this group, especially bidirectional violence. As such, the purpose of this study is to examine the prevalence of PV and bidirectional violence and to investigate risk factors and outcomes of this form of violence using a sample of homeless young adults. Overall, 59% of the sample experienced bidirectional violence. Multivariate results reveal that sexual abuse and neglect are significant correlates of PV. In addition, being either a victim or perpetrator of PV is associated with more severe substance use and higher levels of posttraumatic stress disorder (PTSD). Finally, there is support for bidirectional violence among homeless young adults even after controlling for early histories of maltreatment.
Bringing in the Experts
Authors: Woolley Anita Williams , Gerbasi Margaret E. , Chabris Christopher F. , Kosslyn Stephen M. , Hackman J. Richard
Published: June 2008

This study investigates the separate and joint effects of the inclusion of experts and collaborative planning on the performance of analytic teams. Teams either did or did not include members with expert-level task-relevant cognitive abilities, and either did or did not receive an intervention that fostered collaborative planning. Results support the authors' hypothesis that analytic performance requires both task-appropriate expertise and collaborative planning to identify strategies for optimally using that expertise. Indeed, high expertise in the absence of collaborative planning actually decreased team performance. Teams engaging in collaborative planning were more likely to effectively integrate their information on key aspects of the analytic problem, which significantly enhanced their analytic performance. Furthermore, information integration mediated the effects of the interaction of expertise and collaboration on performance. The implications of the findings for the optimal use of team member skills and the development of team performance strategies are discussed.
Poor Rigor and Political Obduracy: which is the Horse and which is the Cart in Social Work Education?
Authors: Felkner William J.
Published: June 2008

Stoesz and Karger contend that the Council on Social Work Education (CSWE) accreditation has poorly served the profession by perpetuating an environment of low standards epitomized by the very leaders responsible for the credibility of social work as an academic discipline. Graduates are “ill-prepared” and what qualifies as scholarship in the field amounts to “the substitution of ideology for academic rigor.” This author contends that Stoesz and Karger have accurately detailed relevant evidence, but have mislabeled the cause as effect. Rather, ideological directives within the CSWE standards result in lackluster scholarship. Whether or not deans and editors are the “best” the discipline has to offer, they do not view themselves as academic leaders furthering inquiry, but style themselves as military officers training recruits to accomplish objectives already established. Thus, schools of social work are implicitly constructed to attract clones for vocational indoctrination, not seriously thoughtful individuals. Racial quotas for employees further limit available high achievers.
Getting Past the “Government Sucks” Story
Authors: Marens Richard
Published: June 2008

American business scholars have crippled their own work by ignoring the positive contributions of government spending and regulation. Because of the efforts made by corporate executives over the past generation to limit the power of government, business school academics have had little incentive to take a realistic view of the contributions governments make to business success. As a result, these scholars rarely acknowledge either the Keynesian or the Schumpeterian functions of government. This neglect has crippled scholarship, because these two functions have a significant effect on business strategies, organization, entrepreneurship, innovation, marketing, ethics, and business—government relations. Government's Keynesian function stimulates demand for goods and services through purchases and income redistribution. Government's Schumpeterian function lowers the cost of innovation through regulatory requirements, R&D subsidies, and the procurement of expensive new technology. Additional research is required to determine whether business scholars of other nations employ a more nuanced understanding of government's effect on business.
Finding sequence motifs with Bayesian models incorporating positional information: an application to transcription factor binding sites
Authors: Kim Nak-Kyeong , Tharakaraman Kannan , Mariño-Ramírez Leonardo , Spouge John L
Published: June 2008

Background

Biologically active sequence motifs often have positional preferences with respect to a genomic landmark. For example, many known transcription factor binding sites (TFBSs) occur within an interval [-300, 0] bases upstream of a transcription start site (TSS). Although some programs for identifying sequence motifs exploit positional information, most of them model it only implicitly and with ad hoc methods, making them unsuitable for general motif searches.

Results

A-GLAM, a user-friendly computer program for identifying sequence motifs, now incorporates a Bayesian model systematically combining sequence and positional information. A-GLAM's predictions with and without positional information were compared on two human TFBS datasets, each containing sequences corresponding to the interval [-2000, 0] bases upstream of a known TSS. A rigorous statistical analysis showed that positional information significantly improved the prediction of sequence motifs, and an extensive cross-validation study showed that A-GLAM's model was robust against mild misspecification of its parameters. As expected, when sequences in the datasets were successively truncated to the intervals [-1000, 0], [-500, 0] and [-250, 0], positional information aided motif prediction less and less, but never hurt it significantly.

Conclusion

Although sequence truncation is a viable strategy when searching for biologically active motifs with a positional preference, a probabilistic model (used reasonably) generally provides a superior and more robust strategy, particularly when the sequence motifs' positional preferences are not well characterized.
Combination of native and denaturing PAGE for the detection of protein binding regions in long fragments of genomic DNA
Authors: Kaer Kristel , Mätlik Kert , Metsis Madis , Speek Mart
Published: June 2008

Background

In a traditional electrophoresis mobility shift assay (EMSA) a 32P-labeled double-stranded DNA oligonucleotide or a restriction fragment bound to a protein is separated from the unbound DNA by polyacrylamide gel electrophoresis (PAGE) in nondenaturing conditions. An extension of this method uses the large population of fragments derived from long genomic regions (approximately 600 kb) for the identification of fragments containing protein binding regions. With this method, genomic DNA is fragmented by restriction enzymes, fragments are amplified by PCR, radiolabeled, incubated with nuclear proteins and the resulting DNA-protein complexes are separated by two-dimensional PAGE. Shifted DNA fragments containing protein binding sites are identified by using additional procedures, i. e. gel elution, PCR amplification, cloning and sequencing. Although the method allows simultaneous analysis of a large population of fragments, it is relatively laborious and can be used to detect only high affinity protein binding sites. Here we propose an alternative and straightforward strategy which is based on a combination of native and denaturing PAGE. This strategy allows the identification of DNA fragments containing low as well as high affinity protein binding regions, derived from genomic DNA (<10 kb) of known sequence.

Results

We have combined an EMSA-based selection step with subsequent denaturing PAGE for the localization of protein binding regions in long (up to10 kb) fragments of genomic DNA. Our strategy consists of the following steps: digestion of genomic DNA with a 4-cutter restriction enzyme (Alu I, Bsu RI, Tru I, etc), separation of low and high molecular weight fractions of resultant DNA fragments, 32P-labeling with Klenow polymerase, traditional EMSA, gel elution and identification of the shifted bands (or smear) by denaturing PAGE. The identification of DNA fragments containing protein binding sites is carried out by running the gel-eluted fragments alongside with the full "spectrum" of initial restriction fragments of known size. Here the strategy is used for the identification of protein-binding regions in the 5' region of the rat p75 neurotrophin receptor (p75NTR) gene.

Conclusion

The developed strategy is based on a combination of traditional EMSA and denaturing PAGE for the identification of protein binding regions in long fragments of genomic DNA. The identification is straightforward and can be applied to shifted bands corresponding to stable DNA-protein complexes as well as unstable complexes, which undergo dissociation during electrophoresis.