bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review of Stress Analysis Issues for Solid Oxide Fuel Cells
Authors: Shakrawar S. , Pharoah J. G. , Peppley B. A. , Beale S. B.
Published: May 2012

Solid oxide fuel cells represent a potentially important application for ceramic materials. There are, however, some significant issues which can affect the reliability and durability of the cell. The generation of stresses and associated strains in fuel cells is an important concern that needs to be addressed in order to avoid mechanical failure of the cell. Few comprehensive studies have been published on the subject of stress analysis of planar and tubular SOFCs to-date, although various numerical methodologies have been used to obtaining the stress distribution in specific SOFC components over the last 10 years. The objective of this paper is to summarize the state-of-the art of solid oxide fuel cell stress analysis efforts so that the salient issues can be identified.
Embedded 3D Hybrid IC Integration System-in-Package (SiP) for Opto-Electronic Interconnects in Organic Substrates
Authors: Lau John H. , Zhang M. S. , Lee S. W. Ricky
Published: May 2012

A low-cost (with bare chips) and high (optical, electrical, thermal, and mechanical) performance optoelectronic system embedded into a PCB (printed circuit board) or an organic laminated substrate is designed and described. This system consists of a rigid PCB (or a substrate) with an embedded optical polymer waveguide, an embedded vertical cavity surface emitted laser (VCSEL), an embedded driver chip, an embedded serializer, an embedded photo-diode detector, an embedded tans-impedance amplifier (TIA), an embedded deserializer, embedded heat slugs, and a heat spreader. The bare VCSEL, driver chip, and serializer chip are 3D stacked and then attached on one end of the embedded optical polymer waveguide in the PCB. Similarly, the bare photo-diode detector, TIA chip, and deserializer chip are 3D stacked and then attached on the other end of the embedded optical polymer waveguide in PCB. The back-side of the driver or serializer and the TIA or deserializer chips is attached to a heat slug with or w/o a spreader. This novel structural design offers potential solutions for low-cost and high-performance semiconductor circuits with optical devices to realize wide-bandwidth and low-profile optoelectronic packaging for chip-to-chip optical interconnect applications. Optical, thermal management, and mechanical performances are demonstrated by simulations based on optic theory, heat-transfer theory, and continuum mechanics.
Modeling Extraction Regime Transitions for Microchannel Vapor Extraction Map in Two-Phase Cooling Applications
Authors: Salakij Saran , Liburdy James A. , Pence Deborah V.
Published: May 2012

The use of two phase cooling strategies for high power microelectronics has been being widely investigated in order to better control desired operating temperatures and to reduce the mass flow rates required for cooling. However, disadvantages arise when considering the potential for unstable flow conditions and high pressure drop penalties associated with two phase microchannel flows. One possible method to reduce instabilities and maintain a low pressure drop is to extract the vapor phase as it is generated in the channel. This is proposed to be accomplished using at least one wall of the channel fabricated using a hydrophobic porous membrane with the necessary pressure differential to remove vapor while preventing liquid phase break through. To better understand the inherent operating conditions and limitations, conditions for vapor extraction relative to the flow and heat transfer is developed. The extraction regions identified are (i) full extraction, (ii) partial bubble extraction, (iii) two-phase evaporative extraction and (iv) single-phase evaporative extraction. In addition, criteria are presented for stability during bubble extraction. Physics-based criteria to justify the differences between the various regions are presented in terms of non-dimensional parameters. These can be then used to develop an extensive vapor extraction map that can be used to identify operating conditions associated with the extraction regions.
Analytical Modeling and Excimer Laser Micromachining of Microchannel for Medical Devices Development
Authors: Kim Euiseok , Narayan Roger J. , Lee Yuan-Shin
Published: May 2012

In this paper, an analytical modeling of microchannel design and manufacturing with excimer laser micromachining is presented for medical devices development. Micro/Nano fabrication methods have made possible the creation of extremely tiny structures and systems which cannot be generated using traditional manufacturing processes. Current fabrication methods of microchannels generally require serial fabrication processes including a masking process. To overcome the drawbacks of current methods, we propose to use excimer laser micromachining to directly create microfluidic structures. Parametric study of laser machining was conducted before fabrication of microfluidic systems on polyethylene. An analytic modeling of the laser micromachining is presented to predict the machined microstructures and the surface finish. The liquid flow was visualized and studied using fluorescent dye and the velocity was measured to compare liquid behavior in each channel. The presented techniques can be used for the design and manufacturing of micro-scale medical devices development.
A Rule-Based Process Design and Finite Element Analysis of Multistage Deep Drawing of Box Shapes
Authors: Wifi A. S. , Abdel-Mageid R. K. , Gomaa A. H. , Shazly M.
Published: May 2012

In this paper a computer-aided rule-based process design of multi-staged deep drawing of box shaped shells is developed. A decomposition method is adopted in the algorithm for geometry description of the part under consideration. The shell geometry, tooling dimensions and load required are determined for each stage. A finite element analysis is carried out to verify and adjust the output of this process design algorithm. The deformation severity and the resulting strains and thickness variations are investigated. The forming limit diagram (FLD) is adopted as a basic reference to monitor possible part failure in the process.
Isothermalization of an IGBT Power Electronic Chip
Authors: Wang Peng , McCluskey F. Patrick , Bar-Cohen Avram
Published: May 2012

Rapid increases in the power ratings and continued miniaturization of power electronic semiconductor devices have pushed chip heat fluxes well beyond the range of conventional thermal management techniques. The heat flux of power electronic chips for hybrid electric vehicles is now at the level of 100 to 150W/cm2 and is projected to increase to 500 W/cm2 in next generation vehicles. Such heat fluxes lead to higher and less uniform IGBT chip temperature, significantly degrading the device performance and system reliability. Maintaining the maximum temperature below a specified limit, while isothermalizing the surface of the chip, have become critical issues for thermal management of power electronics. In this work, a hybrid cooling system design, which combines microchannel liquid cooling and thermoelectric solid-state cooling, is proposed for thermal management of a 10mm × 10mm IGBT chip. The microchannel heat sink is used for global cooling of the chip while the embedded thermo-electric cooler is employed for isothermalization of the chip. A detailed package level 3D thermal model is developed to explore the potential application of this concept, with an attention focused on isothermalization and temperature reduction of IGBT chip associated with variations in thermoelectric cooler sizes, thermoelectric materials, cooling system designs, and trench structures in the DBC substrate. It is found that a thin-film superlattice TEC can deliver a superior cooling performance by eliminating more than 90% of the temperature non-uniformity on 100∼200 W/cm2 IGBT chips.
Passivation of interfacial defects at III-V oxide interfaces
Authors: Lin Liang , Robertson John
Published: May 2012

The electronic structure of gap states has been calculated in order to assign the interface states observed at III-V oxide interfaces. It is found that As-As dimers and Ga and As dangling bonds can give rise to gap states. The difficulty of passivating interface gap states in III-V oxide interfaces is attributed to an auto-compensation process of defect creation which is activated when an electron counting rule is not satisfied. It is pointed out that oxide deposition needs to avoid burying As dimer states from the free surface, and to avoid sub-surface oxidation during growth or annealing, in order to avoid defect states at the interface or in the subsurface semiconductor.
Human Mesenchymal Stem Cell–Derived Matrices for Enhanced Osteoregeneration
Authors: Zeitouni Suzanne , Krause Ulf , Clough Bret H. , Halderman Hillary , Falster Alexander , Blalock Darryl T. , Chaput Christopher D. , Sampson H. Wayne , Gregory Carl A.
Published: May 2012

Stem cell–generated extracellular matrices provide an optimal environment for bone regeneration in mice.
Decade-Long Safety and Function of Retroviral-Modified Chimeric Antigen Receptor T Cells
Authors: Scholler John , Brady Troy L. , Binder-Scholl Gwendolyn , Hwang Wei-Ting , Plesa Gabriela , Hege Kristen M. , Vogel Ashley N. , Kalos Michael , Riley James L. , Deeks Steven G. , Mitsuyasu Ronald T. , Bernstein Wendy B. , Aronson Naomi E. , Levine Bruce L. , Bushman Frederic D. , June Carl H.
Published: May 2012

Adoptively transferred chimeric antigen receptor T cells have stable stem cell–like persistence for at least a decade and more than 500 years of patient safety.
Vascular COX-2 Modulates Blood Pressure and Thrombosis in Mice
Authors: Yu Ying , Ricciotti Emanuela , Scalia Rosario , Tang Soon Yew , Grant Gregory , Yu Zhou , Landesberg Gavin , Crichton Irene , Wu Weichen , Puré Ellen , Funk Colin D. , FitzGerald Garret A.
Published: May 2012

Deletion of vascular COX-2 predisposes mice to thrombosis and hypertension.
Calming RAGE in Alzheimer’s Disease
Authors: Baker Aaron B.
Published: May 2012

A small molecule that blocks the RAGE receptor shows efficacy in a mouse model of Alzheimer’s disease.
Brother, Can You Spare Some Mitochondria?
Authors: Calfee Carolyn S.
Published: May 2012

Mesenchymal stem cells donate their mitochondria to injured lung epithelial cells.
Bypassing Alzheimer’s Disease
Authors: Nakamura Takahisa
Published: May 2012

After gastric bypass surgery, patients experience reduced inflammation and lower blood levels of proteins related to Alzheimer’s disease.
Modulation of Symbiont Lipid A Signaling by Host Alkaline Phosphatases in the Squid-Vibrio Symbiosis
Authors: Rader Bethany A. , Kremer Natacha , Apicella Michael A. , Goldman William E. , McFall-Ngai Margaret J.
Published: May 2012

The synergistic activity ofVibrio fischerilipid A and the peptidoglycan monomer (tracheal cytotoxin [TCT]) induces apoptosis in the superficial cells of the juvenileEuprymna scolopeslight organ during the onset of the squid-vibrio symbiosis. Once the association is established in the epithelium-lined crypts of the light organ, the host degrades the symbiont’s constitutively produced TCT by the amidase activity of a peptidoglycan recognition protein (E. scolopespeptidoglycan recognition protein 2 [EsPGRP2]). In the present study, we explored the role of alkaline phosphatases in transforming the lipid A of the symbiont into a form that changes its signaling properties to host tissues. We obtained full-length open reading frames for twoE. scolopesalkaline phosphatase (EsAP) mRNAs (esap1andesap2); transcript levels suggested that the dominant light organ isoform is EsAP1. Levels of total EsAP activity increased with symbiosis, but only after the lipid A-dependent morphogenetic induction at 12 h, and were regulated over the day-night cycle. Inhibition of total EsAP activity impaired normal colonization and persistence by the symbiont. EsAP activity localized to the internal regions of the symbiotic juvenile light organ, including the lumina of the crypt spaces where the symbiont resides. These data provide evidence that EsAPs work in concert with EsPGRPs to change the signaling properties of bacterial products and thereby promote persistent colonization by the mutualistic symbiont.

IMPORTANCEThe potential for microbe-associated molecular patterns (MAMPs) to compromise host-tissue health is reflected in the often-used nomenclature for these molecules: lipopolysaccharide (LPS) is also called “endotoxin” and the peptidoglycan monomer is also called “tracheal cytotoxin” (TCT). With constant presentation of MAMPs by the normal microbiota, mechanisms to tolerate their effects have developed. The results of this contribution provide evidence that host alkaline phosphatases (APs) dephosphorylate and inactivate the symbiont MAMP lipid A. As such, APs work in synergy with a peptidoglycan recognition protein, which inactivates symbiont-exported TCT, to alter the symbiont MAMPs and promote persistence of the partnership. Not only may these activities serve to “tame” the MAMPs, but also the resulting products may themselves be important signals in persistent mutualisms. The finding of lipid A modification by APs in an invertebrate mutualism provides evidence that this specific strategy for dealing with symbiotic partners is conserved across the animal kingdom.
Rapid rise in incidence of Irish paediatric inflammatory bowel disease
Authors: Hope B , Shahdadpuri R , Dunne C , Broderick A M , Grant T , Hamzawi M , O'Driscoll K , Quinn S , Hussey S , Bourke B
Published: May 2012

Aims

To describe the change in incidence of paediatric inflammatory bowel disease (IBD) observed at the National Centre for Paediatric Gastroenterology, Hepatology and Nutrition, and to determine whether the presenting disease phenotype and disease outcomes have changed during the past decade.

Methods

The annual incidence of IBD in Irish children aged <16 years was calculated for the years 2000–2010. Two subsets of patients, group A (diagnosed between 1 January 2000 and 31 December 2001), and group B (diagnosed between 1 January and 31 December 2008) were phenotyped according to the Paris Classification. Phenotype at diagnosis and 2-year follow-up were then compared.

Results

406 new cases of IBD were identified. The incidence was 2.5/100 000/year in 2001, 7.3 in 2008 and 5.6 in 2010, representing a significant increase in the number of new cases of Crohn's disease (CD) and ulcerative colitis (UC). There were 238 cases of CD; 129 of UC; and 39 of IBD unclassified. Comparing groups A and B, no differences were found in disease location at diagnosis or, for CD, in its behaviour.

Conclusions

There has been a substantial and sustained increase in the incidence of childhood UC and CD in Ireland over a relatively short period of time. However, disease phenotype at diagnosis has not changed. At 2 years follow-up, CD appears to progress less frequently than in some neighbouring countries. These variations remain unexplained. Prospective longitudinal studies will help to elucidate further the epidemiology of childhood IBD.
Faculty prefer continuity with medical students in the emergency department
Authors: Bernard Aaron William , Kman Nicholas E , Betz Bret , Khandelwal Sorabh , Caterino Jeffrey M
Published: May 2012

Introduction

The aim of this investigation was to better understand emergency medicine (EM) faculty opinions as they relate to continuity with students.

Methods

This was a prospective cohort study of faculty supervising students completing an EM clerkship. Student schedules were aligned to maximise continuity with faculty. Faculty completed surveys prior to the start of the study and again at the end of the study period.

Results

Faculty generally indicated a favourable opinion regarding continuity with students. Significant change was noted in two survey questions from pre- to post-intervention: faculty reported higher motivation to teach and felt the students' learning experience was better with improved continuity.

Conclusion

EM faculty express theoretical optimism regarding the value of improved continuity between teacher and learner. This positive sentiment persisted after actual experience with students on a shift allocation model that aligns faculty and student schedules.
Scope to improve: a multi-centre audit of 16 064 colonoscopies looking at caecal intubation rates, over a 2-year period
Authors: Verma Ajay Mark , McGrath Nadine , Bennett Paula , de Caestecker John , Dixon Andrew , Eaden Jayne , Wurm Peter , Chilton Andrew
Published: May 2012

Objective

Colonoscopy is the ‘gold standard’ assessment for large bowel mucosal pathology, but a complete examination is essential. The first national colonoscopy audit carried out in 1999 demonstrated caecal intubation rates (CIRs) of 56.9%. As a result, the Joint Advisory Group (JAG) on gastrointestinal endoscopy launched a programme of continuous quality improvement. JAG recommends that practitioners undertake 100+ procedures per annum with a target CIR of 90%. This current audit provides an assessment of performance against this quality standard.

Design

Data were collected from all procedures undertaken in 2008–2009 from six hospitals across three English regions.

Results

16064 colonoscopies performed: CIR = 90.57% (95% CI 90.11% to 91.01%). Operators doing 100+ procedures per annum, CIR=91.76% (91.24% to 92.25%). Operators doing <100 procedures per annum, CIR=87.77% (86.82% to 88.67%). Gastroenterologists, CIR=91.01% (90.32% to 91.70%). Surgeons, CIR=91.03% (90.27% to 91.79%). Other practitioners, CIR=81.51% (78.79% to 84.22%). Bowel cancer screening programme (BCSP) colonoscopies, CIR=97.71% (97.07% to 98.34%). Non-screening colonoscopies, CIR=88.31% (95% CI 87.68% to 88.94%).

Conclusion

This audit of 16064 colonoscopies across three regions demonstrates aggregated achievement of the CIR quality standard. However, there is a significant performance gap when comparing BCSP colonoscopists with non-screening colonoscopists and the overall CIR of >90% is supported by the volume of BCSP colonoscopy.

Endoscopists performing low volume colonoscopy (<100 per annum), have CIR of <90%. Endoscopists with low volume practice who do not meet the quality standards should engage in skills augmentation plus further training and increase volume of colonoscopy with local mentorship, or stop performing colonoscopy.
Survey of travel‐related problems in dogs
Authors: Mariti C. , Ricci E. , Mengoli M. , Zilocchi M. , Sighieri C. , Gazzano A.
Published: May 2012

The aim of this study was to quantitatively assess the kind of transport dogs undergo, the behaviours displayed during transport, the prevalence of travel‐related problems in dogs and owners' interventions to solve these problems. A convenience sample of 907 dog owners completed a questionnaire containing 16 multiple‐choice questions. All dogs had been transported by car at least once, but 4.7 per cent were no longer transported. 76.2 per cent of animals always responded positively to car transport, the rest showing or having shown problems (6.7 per cent always reacted negatively). Dogs were found to be more excited than inhibited during car transport. The vast majority (86.0 per cent) had become used to travelling by car as puppies; this made them less likely to develop problems (6.3 per cent v 24.1 per cent; χ2  = 19.886, P = 0.000). If dogs were transported only to veterinary clinics, they were more prone to respond negatively to car transport (46.4 per cent v 22.7 per cent; χ2  = 7.245, P = 0.007). For dogs reported as problematic (23.8 per cent of the sample), 96.3 per cent of the owners did not administer any treatments or other substances, 48.7 per cent did not seek any advice, and 40.4 per cent of them made attempts to solve the problem by themselves.
External coaptation of rostral mandibular fractures in calves
Authors: Taguchi K. , Hyakutake K.
Published: May 2012

Six cases of rostral mandibular fracture with considerable displacement were treated successfully by external coaptation. Four cases were simple and two were compound fractures. After xylazine sedation and manual reduction of the fractures, the casting tape was laminated to make a rigid splint below the mandibles and then the splint was secured using the casting tape passing the nasal bridge and cranial and/or caudal to the ears as it encircled the head. During application of the tape, a PVC pipe 25 mm in diameter was held in its jaws to keep the mouth open so that the calf could suckle. Simple rostral mandibular fractures were cured after two weeks of cast immobilisation and compound fractures after about three weeks. This method is easy and non‐stressful and provided a good prognosis in the present cases.
Exercise-induced vasodilation is associated with menopause stage in healthy middle-aged women
Authors: Moore David J. , Gonzales Joaquin U. , Tucker Steven H. , Elavsky Steriani , Proctor David N.
Published: May 2012

Leg exercise hemodynamics during single-leg knee extensions were compared among healthy groups of early perimenopausal (n = 15), late perimenopausal (n = 12), and early postmenopausal (n = 11) women. Femoral blood flow (FBF) and vascular conductance (FVC) at rest and during very light work rates (0 and 5 W) were similar among all three menopause stage groups. Vascular responses at 10 W (FBF) and 20 W (FBF and FVC) were significantly higher (P < 0.05) in early perimenopausal compared with late perimenopausal women. At 15 and 25 W, FBF and FVC were similar between late perimenopausal and early postmenopausal groups but higher (P < 0.05) in early perimenopausal women as compared with the other two menopausal groups. In the combined sample of all three menopause stage groups, follicle-stimulating hormone was significantly correlated with vascular conductance during submaximal (15 W) exercise (R = –0.56, P < 0.001), even after adjustment for age, fitness, LDL cholesterol, and abdominal fat (R = –0.46, P = 0.005). Collectively, these findings suggest that in middle-aged women, there is an association between menopause stage and leg vascular responsiveness during exercise.
Cardiac responses of rats submitted to postnatal protein restriction
Authors: Murça Tatiane Moisés , Magno Tatiana Soares dos Reis , De Maria Marilda Luz de Andrade , Capuruço Carolina Andrade Bragança , Chianca Deoclécio Alves , Ferreira Anderson José
Published: May 2012

Undernutrition during critical stages of development and childhood has important effects on cardiovascular homeostasis. The present study was undertaken to evaluate the in vivo and ex vivo cardiac function of rats submitted to postnatal protein restriction. Male Wistar rats (28 days old) were fed a regular (20%) or low-protein (6%) diet over 5 weeks. After this period, cardiac function was analyzed by echocardiography and isolated heart preparation. Furthermore, the density of cardiac noradrenergic fibers and hematological profile were evaluated. We found that malnourished rats exhibited elevated arterial blood pressure, increased fractional shortening (echocardiography), increased systolic tension, increased ±dT/dt (isolated heart technique), impaired diastolic function characterized by a slight increase in the left ventricular end-diastolic diameter (echocardiography) and decreased diastolic tension (isolated heart technique), and cardiac hypertrophy evidenced by augmentation of the posterior left ventricular wall and discrete hematological changes. In addition, malnourished rats exhibited increased noradrenergic fiber density in their hearts (0.08% ± 0.02% area in control rats vs. 0.17% ± 0.03% area in malnourished rats). Our current data demonstrate that postnatal protein restriction causes cardiac adaptation characterized by an early overworking heart. This is at least in part mediated by an increase in the efferent sympathetic fibers to the heart. These findings provide important information for efforts to prevent and manage the consequences of undernutrition in the human population.
Neuromuscular fatigue recovery following rapid and slow stretch–shortening cycle movements
Authors: Wadden Katie P. , Button Duane C. , Kibele Armin , Behm David G.
Published: May 2012

The purpose of this study was to investigate underlying mechanisms and neuromuscular recovery patterns following rapid and slow stretch–shortening cycle (SSC) movements performed to fatigue. Fourteen (10 moderately trained (MT) and four highly trained (HT)) subjects completed rapid and slow SSC movements to fatigue. The rapid SSC movement consisted of continuous drop jumps from a 30 cm platform until a predetermined jump height was no longer maintained, and the slow SSC movement consisted of continuous squats to 90° of knee flexion at a load of 65% of subject’s one-repetition maximum until no further repetitions could be completed. Although blood lactate measures were significantly (p < 0.002) higher after the rapid SSC condition versus after the slow SSC condition, the recovery of neuromuscular properties (maximum voluntary contractions, twitch force, muscle compound action potential) following the two conditions to fatigue did not differ. The duration of the rapid SSC movement was dependent on the training status of the subject; HT subjects performed the rapid SSC longer (68.2%) than the MT subjects until fatigued. Thus, the neuromuscular fatigue recovery patterns were independent of the type of SSC movement, condition duration, and subject training status. Because rapid and slow SSC exercises induce similar fatigue patterns, training programs incorporating rapid SSC exercises can be developed similar to that prescribed in traditional slow SSC resistance training programs.
Trends in aerobic fitness among Canadians, 1981 to 2007–2009
Authors: Craig Cora L. , Shields Margot , Leblanc Allana G. , Tremblay Mark S.
Published: May 2012

Public health surveillance systems often monitor physical activity trends, but fitness assessment is relatively rare. This study investigated secular changes in aerobic fitness among Canadian adults and children. Participants aged 8–69 years were from 2 nationally representative surveys, conducted in-home in 1981 and in mobile examination centers in 2007–2009. In both surveys, submaximal step tests using progressive age- and sex-specific exercise stages were completed after initial screening (Physical Activity Readiness Questionnaire, heart rate, blood pressure). Between surveys, the step-test protocol had been modified to reduce underestimation of fitness among fitter and older individuals. Maximal oxygen uptake was estimated for adults using validated historical and updated prediction equations, adjusted to reflect protocol differences. Because these equations are not validated for young people, maximal aerobic power was predicted at a heart rate of 200 beats·min–1by regressing observed heart rates on the oxygen costs of stepping for children and youth who completed at least 2 exercise stages. Overall, despite protocol differences, we found that the aerobic fitness levels of Canadians were lower in 2007–2009 than in 1981, with declines apparent in all age and both sex groups, thereby increasing the number of those at risk of adverse health outcomes. Future work is required to validate prediction equations of aerobic fitness for young people to make it possible to compare fitness levels over the lifespan and across time.
Agreement between anthropometric and dual-energy X-ray absorptiometry assessments of lower-limb volumes and composition estimates in youth-club rugby athletes
Authors: Carvalho Humberto M. , Coelho-e-Silva Manuel J. , Franco Sérgio , Figueiredo António J. , Tavares Óscar M. , Ferry Béatrice , Hidalgo-Hermanni Ilsabeth , Courteix Daniel , Malina Robert M.
Published: May 2012

The purpose of this study was to assess the agreement of lower-limb volume estimates based on anthropometry and dual-energy X-ray absorptiometry (DXA) as a reference method in male rugby athletes. Predictive models using body mass and skinfolds were tested to improve the relative agreement between protocols (anthropometry, DXA). Rugby players (n = 41; 19.9 ± 2.2 years) volunteered for the study. Lower-limb total and fat-free volumes were estimated by anthropometry and also derived using DXA. Cross-validation between the anthropometry technique and DXA was then performed. Lower-limb volume estimates by anthropometry overestimated reference values and tended to be further from the reference values with the increase of scale. For the total sample, standard errors of measurement for volume estimates by anthropometry were 1.99 L and 1.34 L for total and fat-free volumes, respectively. Correlations with reference values were 0.81 for lower-limb volume and 0.90 for lower-limb fat-free volume. Correlations between estimated prediction equations and reference values showed higher correlations (r = 0.96 for lower-limb volume and r = 0.93 for lower-limb fat-free volume) compared with anthropometric estimates. Overall, the agreement of anthropometry method to quantify lower-limb volumes with DXA as a reference in young adult rugby players is acceptable and is a practical method when more expensive and complex techniques are not available. The consideration of body mass and lower-limb skinfolds increases the precision of lower-limb volume estimates using anthropometry in the young adult rugby players.
Fish oil induced hyperlipidemia and oxidative stress in BioF1B hamsters is attenuated by elderberry extract
Authors: Dubey Pratibha , Jayasooriya Anura P. , Cheema Sukhinder K.
Published: May 2012

We have previously reported fish oil induced hyperlipidemia in BioF1B hamsters compared with Golden Syrian (GS) hamsters. Elderberry (Sambucus nigra L.) extract is abundant in anthocyanins and is believed to exert cardioprotective effects primarily by virtue of its hypolipidemic and antioxidant potential. In the current study, high-fat fish oil feeding increased oxidative stress in BioF1B hamsters compared with GS hamsters; this increase was associated with increased levels of omega-3 polyunsaturated fatty acids in plasma and liver. We then investigated whether cosupplementation with anthocyanin-rich elderberry extract would reverse fish oil induced hyperlipidemia and reduce lipid peroxidation in BioF1B hamsters. Plasma and hepatic lipids decreased significantly when hamsters were fed diets containing elderberry extract along with fish oil. Both plasma and liver thiobarbituric acid reactive substances showed significant reductions upon cosupplementation with elderberry extract in fish oil fed BioF1B hamsters. Our findings demonstrate that cosupplementation with elderberry extract reverses hyperlipidemia and lipid peroxidation observed with dietary fish oil alone in BioF1B hamsters.
Characterizing the binding of nucleotide ATP on serum albumin by 31P NMR diffusion
Authors: Song Zhiyan , Zhao Hua , Olubajo Olarongbe , Hall Lewis B. , Orr Chauncey N. , Askew Courtney B.
Published: May 2012

The pulsed-field-gradient (PFG) 31P NMR diffusion spectra were measured under varied sample conditions to characterize the low-affinity binding of adenosine 5′-triphosphate (ATP) on human serum albumin (HSA) or bovine serum albumin (BSA). The NMR diffusion constants of ATP, ATP–HSA, or ATP–BSA were illustrated as function of ATP concentrations. The binding curves of ATP–HSA and ATP–BSA were identical but strikingly different from the ATP curve. Using a “Scatchard plot”, the apparent binding constant (K) and number of ATP binding sites (n) on serum albumin were evaluated as K = 75.25 (mol/L)–1 and n = 10, respectively. At a pH < 5.0 and a pH > 9.0 or a temperature > 45 °C, the diffusion data of ATP–HSA were found to increase remarkably, suggesting that the dissociation of ATP from HSA was largely enhanced, probably because of pH- or heat-induced protein structural change, degradation, or aggregation. In addition, our data indicated that ADP was strongly competitive with ATP for the low-affinity binding to HSA, but heptanone and Cl– were essentially noncompetitive. These results are important for further elucidating the interaction of ATP with serum albumin and its possible effect on related bioprocesses. The method can be well applied to study the binding of other nucleotides/nucleosides on proteins.
Synthesis of new γ-lactones from preactivated monosubstituted pyrazines and TMS–ketene acetals
Authors: Garduño-Alva Azucena , Ortega-Alfaro M. Carmen , López-Cortés José G. , Chávez Isabel , Barroso-Flores Joaquin , Toscano Rubén A. , Rudler Henri , Álvarez-Toledano Cecilio
Published: May 2012

The double addition of bis(trimethylsilyl) ketene acetals (1a–1b, R1 = CH3, –(CH2)5–) to 2-substituted pyrazines promoted by triflic anhydride leads to γ-lactones in a single step. A systematic study involving electron-withdrawing and electron-donating groups (R2 = CN, COOMe, PhCH=CH, Cl, Me, OMe) in the pyrazine ring reveals a strong dependence of electronic effects on the regiochemistry of nucleophilic addition.
Antimicrobial characterization and safety aspects of the bacteriocinogenicEnterococcus hiraeF420 isolated from Moroccan raw goat milk
Authors: Achemchem F. , Cebrián R. , Abrini J. , Martínez-Bueno M. , Valdivia E. , Maqueda M.
Published: May 2012

The F420 strain, isolated from raw goat milk and identified as Enterococcus hirae , was selected because of its strong activity against Gram-positive bacteria, including Listeria monocytogenes . Interestingly, the F420 strain lacks the virulence genes and decarboxylase activity of histidine, lysine, and ornithine, and it is susceptible to 11 of 14 tested antibiotics, including vancomycin. The antimicrobial compounds produced by E. hirae F420 strain showed high resistance to heat treatment and to acidic and basic pHs. The MALDI-TOF mass spectrometry analysis coupled with the sequence of peptide and structural gene analysis of one of the purified enterocins showed 100% identity with enterocin P (EntP), previously described in E. faecium strains. The structural gene for EntP is located on a plasmid of 65 kb. Other enterocins with molecular mass higher than 7 kDa were also detected. This is the first report of the production of EntP by E. hirae species naturally occurring in foods. The biotechnological characteristics of the F420 strain and its enterocins indicate their potential for application in the control of L. monocytogenes and other undesirable bacteria in food systems.
Further characterization and determination of the single amino acid change in thetsI138reovirus thermosensitive mutant
Authors: Lemay Guy , Bisaillon Martin
Published: May 2012

Many temperature-sensitive mutants have been isolated in early studies of mammalian reovirus. However, the biological properties and nature of the genetic alterations remain incompletely explored for most of these mutants. The mutation harbored by the tsI138 mutant was already assigned to the L3 gene encoding the λ1 protein. In the present study, this mutant was further studied as a possible tool to establish the role of the putative λ1 enzymatic activities in viral multiplication. It was observed that synthesis of viral proteins is only marginally reduced, while it was difficult to recover viral particles at the nonpermissive temperature. A single nucleotide substitution resulting in an amino acid change was found; the position of this amino acid is consistent with a probable defect in assembly of the inner capsid at the nonpermissive temperature.
Distribution of class 1 integrons among enteropathogenicEscherichia coli
Authors: Najibi S. , Bakhshi B. , Fallahzad S. , Pourshafie M.R. , Katouli M. , Sattari M. , Alebouyeh M. , Tajbakhsh M.
Published: May 2012

The aim of this study was to investigate the incidence of and resistance gene content of class 1 integrons among enteropathogenic Escherichia coli (EPEC) and non-EPEC and to investigate intraspecies genetic diversity of EPEC strains isolated from children with diarrhea in Iran. Twenty-eight EPEC and 16 non-EPEC strains isolated from children with diarrhea were tested for the presence of a class 1 integron associated integrase gene (int1). Sequence analysis was performed to identify the resistance gene content of integrons. Genetic diversity and cluster analysis of EPEC isolates were also investigated using enterobacterial repetitive intergenic concensus – polymerase chain reaction (ERIC–PCR) fingerprinting. Twenty-three (82%) EPEC isolates and 11 (68.7%) non-EPEC isolates harbored the int1 gene specific to the conserved integrase region of class 1 integrons. Sequence analysis revealed the dominance of dfrA and aadA gene cassettes among the isolates of both groups. ERIC–PCR fingerprinting of EPEC isolates revealed a high diversity among these isolates. The widespread distribution of 2 resistance gene families (dfrA and aadA) among both groups of EPEC and non-EPEC isolates indicates the significance of integrons in antibiotic resistance transfer among these bacteria. Furthermore, clonal diversity of EPEC isolates harbouring a class 1 integron also suggests the circulation of these mobile elements among a diverse population of EPEC in this country.
THREE-STEP PROJECTION METHOD FOR GENERAL VARIATIONAL INEQUALITIES
Authors: BNOUHACHEM ABDELLAH , NOOR MUHAMMAD ASLAM
Published: May 2012

In this paper, we suggest and analyze a new three-step iterative projection method for solving general variational inequalities in conjunction with a descent direction. We prove that the new method is globally convergent under suitable mild conditions. An example is given to illustrate the advantage and efficiency of the proposed method.
DNA-porphyrin hybrids as reaction centers for photosensitized ene reactions with singlet oxygen
Authors: Haug Rüdiger , Griesser Helmut , Sabirov Thomas , Richert Clemens
Published: May 2012

Recent developments in DNA-mediated nanostructuring have paved the way for the development of novel reaction centers. As part of a project focused on nanostructured reaction centers for reactions catalyzed by porphyrins, we have developed a solid-phase synthesis of tetrakis(p-hydroxyphenyl)porphyrin-oligonucleotide hybrids. In these hybrids, up to four nucleic acid chains are linked to the phenolic substituents of the porphyrin via phosphodiester linkages. A representative hybrid with one oligonucleotide chain of the sequence TTAA was found to survive light irradiation under aerobic conditions for 2 h with less than 35% oxidation of the DNA chain. An assay measuring the diastereo- and enantioselectivity of the photosensitized ene reaction of mesitylol with singlet oxygen was set up that provides diastereomeric ratios via NMR of aliquots of the reaction solution. Enantiomers were separated gas chromatographically on a chiral stationary phase and were assigned based on the product distribution obtained with an enantiomerically enriched starting material. Our results are a starting point for the exploration of nanostructured reaction media based on DNA and porphyrins.
Photophysics of novel 22π porphyrinoids
Authors: Mártire Daniel O. , Russell Sigrid , Dietrich Hans-Jürgen , Cobos Carlos J. , Braslavsky Silvia E.
Published: May 2012

The photophysical properties of toluene solutions of two new 22π expanded porphycene compounds were measured using a combination of various steady-state and time-resolved techniques. The determined triplet energy (E T = 109 ± 3) kJ.mol-1, coincident with the calculated E T = (96.0 ± 10) kJ.mol-1, of both red absorbing compounds is higher than the energy required to excite ground state molecular oxygen to singlet molecular oxygen. However, the intersystem crossing yield is very low (ca. 10-2), which makes these compounds poor photosensitizers. The triplet state yield of the two expanded 22π porphyrinoid compounds is much lower than that of the parent porphycene, whereas their fluorescence is as high (ca. 30%) as the value for porphycene. The slower than diffusional quenching rate constant of a porphycene triplet state by the two new compounds reflects a steric hindering factor of the exothermic energy transfer.
Primary Factor Extracted for Anomalous Decline of Drain Current in Metal–Oxide–Semiconductor Field-Effect Transistors
Authors: Abe Kazuhide , Sasaki Tadahiro , Itaya Kazuhiko
Published: May 2012

A statistical approach has been exploratively applied to extract an influential factor of anomalous decreases in drain current observed in metal–oxide–semiconductor field-effect transistors with large channel widths. Since negative slopes were detected in drain current vs drain voltage (I
d–V
ds) curves even with negligible heat quantity or density, the self-heating effect was excluded as the primary factor. In contrast, the aspect ratio of the device areas showed a significant influence. These results support the validity of a hypothesis, namely, that acoustic standing waves are excited and thereby the probabilities of impact ionizations are synchronously magnified in the devices.
A Comparative Study on the Optical and Electrical Properties of Si-Doped Polar and Nonpolar GaN
Authors: Song Keun Man , Kim Hogyoung
Published: May 2012

Si-doped polar (c-plane) and nonpolar (a-plane) GaN layers grown by metal–organic vapor phase epitaxy (MOVPE) were comparatively investigated using photoluminescence (PL) and Hall-effect measurements. While c-plane GaN revealed both band-acceptor and donor–acceptor transitions, the PL spectra for a-plane GaN were related to extended defects such as basal stacking faults (BSFs) and prismatic stacking faults (PSFs). A new emission peak was observed at 3.361 eV in the Si-doped a-plane GaN, which was attributed to Si-doping-induced defects. The temperature-dependent Hall-effect measurements showed that for c-plane GaN, mobility was dominated by optical phonon and ionized impurity scattering at high and low temperature, respectively. Conversely, for a-plane GaN, the scattering mechanism due to dislocations was dominant at all temperatures.
Thermally Dried Ink-Jet Process for 6,13-Bis(triisopropylsilylethynyl)-Pentacene for High Mobility and High Uniformity on a Large Area Substrate
Authors: Ryu Gi Seong , Lee Myung Won , Jeong Seung Hyeon , Song Chung Kun
Published: May 2012

In this study we developed a simple ink-jet process for 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene), which is known as a high-mobility soluble organic semiconductor, to achieve relatively high-mobility and high-uniformity performance for large-area applications. We analyzed the behavior of fluorescent particles in droplets and applied the results to determining a method of controlling the behavior of TIPS-pentacene molecules. The grain morphology of TIPS-pentacene varied depending on the temperature applied to the droplets during drying. We were able to obtain large and uniform grains at 46 °C without any “coffee stain”. The process was applied to a large-size organic thin-film transistor (OTFT) backplane for an electrophoretic display panel containing 192×150 pixels on a 6-in.-sized substrate. The average of mobilities of 36 OTFTs, which were taken from different locations of the backplane, was 0.44±0.08 cm2·V-1·s-1, with a small deviation of 20%, over a 6-in.-size area comprising 28,800 OTFTs. This process providing high mobility and high uniformity can be achieved by simply maintaining the whole area of the substrate at a specific temperature (46 °C in this case) during drying of the droplets.
Hybrid Method for Analyzing the Torsional Vibration of One-Dimensional Phononic-Band-Gap Shafts
Authors: Li Lixia , Chen Tianning , Wu Jiuhui , Wang Xiaopeng , Wang Zhaofeng
Published: May 2012

A hybrid method combining the transfer-matrix and lumped-mass methods is proposed to study the band gaps of torsional vibration in one-dimensional (1D) phononic band gap (PBG)-like shafts, which periodically arrange local resonant multilayer rings. The present method shows advantages over the transfer-matrix and lumped-mass methods for determining the inertia of rubber rings and fast convergence with less computational requirements. For light local resonators, the torsional band gaps, which were studied in three 1D PBG-like shafts by the hybrid method, agree well with those studied by the finite method. In addition, more precise evaluations of the starting frequency of the band gaps were carried out analytically. The methodology of the approach presented can also be employed to study the band gaps of bending and longitudinal waves.
Optical Characterization of Double Peak Behavior in 101̄1 Semipolar Light-Emitting Diodes on Miscut m-Plane Sapphire Substrates
Authors: Choi Sang-Bae , Bae Si-Young , Lee Dong-Seon , Kong Bo Hyun , Cho Hyung Koun , Song Jung-Hoon , Ahn Byung-Jun , Keading John F. , Nakamura Shuji , DenBaars Steven P. , Speck James S.
Published: May 2012

{101̄1} semipolar GaN-based light-emitting diodes (LEDs) grown on 1° miscutm-plane sapphires substrates via metal organic chemical vapor deposition showed undulated surface morphology with ridges and valleys. On the ridge regions, two dominant emission peaks, one at a shorter wavelength (∼438 nm) and one at a longer wavelength (∼490 nm), were observed using electroluminescence and micro-photoluminescence. In the valley regions, the longer peak was observed to be significantly quenched due to the grain boundary. The origin of the longer peak is believed to be not only inhomogeneous distribution of In composition in multiple quantum wells (MQWs) but also strong localization around the ridge region. Moreover, thickness variation of faceted MQWs could be associated with the peak broadening in 101̄1 semipolar LEDs. The results were also confirmed by cathodoluminescence and cross-sectional transmission electron microscopy.
Application of a Continued-Fraction-Based Theory to Line-Profile in Mn-Doped GaN Film
Authors: Park Jung-Il , Lee Hyeong-Rag , Lee Su-Ho
Published: May 2012

Starting with the Kubo formalism and using the projection operator technique (POT) introduced by Kawabata, the optical quantum transition line-profiles (QTLPs) formula for a Mn-doped wurtzite GaN film was derived as a function of temperature at a frequency of 9.49 GHz (X-band), on the basis of continued fraction representation (CFR) which is a counterpart of the conventional series expansion (CSE). Utilizing this formula we obtained the fine-structure parameter a - F = 9.4 ×10-4 cm-1 and fitting parameter ζ= 4.1. The optical quantum transition half-widths (QTHWs) obtained with the use of these parameters agrees quite well with the existing experimental result in the temperature region T > 20 K. The QTHWs increase with increasing temperature due to the interaction of electrons with optical phonons. Thus, the present technique is considered to be more convenient to explain the resonant system as in the case of other optical transition problems.
Monomode Optical Waveguides in Yb3+-Doped Silicate Glasses Produced by Low-Dose Carbon Ion Implantation
Authors: Liu Chun-Xiao , Cheng Shu , Li Wei-Nan , Wei Wei , Peng Bo
Published: May 2012

The planar waveguide has been fabricated in the Yb3+-doped silicate glass by 4.0 MeV C2+ ion implantation at a dose of 2×1014 ions/cm2. The guided modes are measured using a model 2010 prism coupler at 633 nm. The near-field profiles of the planar waveguide are obtained with an end-face coupling system. The refractive index profile of the waveguide is reconstructed by the intensity calculation method, which shows a typical “enhanced well + barrier” distribution. The SRIM'2006 code is carried out to simulate the energy loss during the implantation in order to obtain a better understanding of the waveguide formation. After post-implantation treatment at 260 °C for 1 h, the waveguide possesses a propagation loss of ∼1.42 dB/cm. The acceptable guiding properties suggest that further waveguide lasers may be realized on the C-implanted Yb3+-doped silicate glass waveguides.