bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of fluorine‐plasma‐induced deep centers in AlGaN/GaN heterostructure by persistent photoconductivity
Authors: Li B. K. , Chen K. J. , Lau K. M. , Ge W. K. , Wang J. N. 
Published: April 2008

AbstractFluorine plasma treatment technique can effectively incorporate negatively‐charged fluorine ions in the AlGaN barrier and deplete the two‐dimensional electron gas in the channel of AlGaN/GaN high electron mobility transistors (HEMTs). In applications, this technique can be used to convert the device from depletion‐mode to enhancement‐mode. To reveal the underlying physical mechanisms, the properties of F‐related deep centers in an AlGaN/GaN heterostructure are studied using temperature‐dependent persistent photoconductivity (PPC) and Hall measurements. Weakly temperature‐independent 2DEG mobility and much more pronounced PPC effect are observed in the F‐treated sample. Energy barrier for electron‐recapture by the F‐related centers has also been extracted from the PPC decay behaviour. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical conduction in cubic GaN films grown on GaAs(001) by RF‐MBE
Authors: Kohno M. , Nakamura T. , Kataoka T. , Katayama R. , Onabe K. 
Published: April 2008

AbstractThe electrical conduction property of c‐GaN films grown on GaAs(001) by RF‐MBE has been studied in relation with the amount of the hexagonal phase inclusion, or cubic phase purity. In a high‐phase‐purity (93%) film, the electron concentration and mobility at 300 K are typically 8×1017 cm–3 and 110 cm2/V‐s, respectively. It is known that a parallel conduction is occurring in which the high mobility region somewhat away from the hetero‐interface dominates the conduction at higher currents. In a lower‐phase‐purity (75%) film, it is indicated that the low mobility region extends over the larger region of the film. Above the cubic phase purity of about 90%, the electron concentration rapidly decreases and the mobility rapidly increases by one or two orders of magnitudes, suggesting that the stacking faults are the major source of the carrier electrons and causing the scattering centers responsible for the low mobility region. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN ultraviolet avalanche photodiodes fabricated on free‐standing bulk GaN substrates
Authors: Zhang Yun , Yoo Dongwon , Limb Jae‐Boum , Ryou Jae‐Hyun , Dupuis Russell D. , Shen Shyh‐Chiang 
Published: April 2008

AbstractWe report high‐performance MOCVD‐grown GaN ultraviolet (UV) p‐i‐n avalanche photodiodes (APD) on bulk GaN substrates. The fabricated APD achieved avalanche gain of > 3 × 104 and low leakage current density (<10–7 A/cm2) at voltages below 50% of the device avalanche breakdown voltage. To the best of our knowledge, this is the highest linear gain reported to date among III‐N‐based UV APDs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AlxGa1–xN‐based avalanche photodiodes with high reproducible avalanche gain
Authors: Tut Turgut , Gokkavas Mutlu , Ozbay Ekmel 
Published: April 2008

AbstractWe report high performance solar‐blind photodetectors with reproducible avalanche gain as high as 1570 under ultraviolet illumination. The solar‐blind photodetectors have a sharp cut‐off around 276 nm. The dark currents of the 40 μm diameter devices are measured to be lower than 8 femto‐amperes for bias voltages up to 20 V. The responsivity of the photodetectors is 0.13 A/W at 272 nm under 20 V reverse bias. The thermally limited detectivity is calculated as D* = 1.4 × 1014 cm Hz1/2 W–1 for a 40 µm diameter device. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
2.3 nm barrier AlN/GaN HEMTs with insulated gates
Authors: Deen David , Zimmermann Tom , Cao Yu , Jena Debdeep , Xing Huili Grace 
Published: April 2008

AbstractUltra‐shallow channel AlN/GaN high electron mobility transistor (HEMT) structures with a 2.3 nm AlN barrier were grown by plasma‐assisted molecular beam epitaxy (PAMBE) on sapphire substrates. They exhibit 2‐D electron gas densities of ∼ 1.4 x 1013 cm–2 and electron hall mobilities of ∼ 1600 cm2/Vs. Insulated‐gate stacks of SiNx/Al2O3/Ni/Au were used to suppress the gate leakage current, which is found to largely stem from dislocation‐assisted leakage paths. AlN/GaN HEMTs with 250 nm gate length showed DC output current densities of up to 1.6 A/mm, transconductances of ∼ 300 mS/mm, and extrinsic ft/fmax of 24/52 GHz. These performance metrics demonstrate that these ultra‐shallow channel AlN/GaN heterostructures hold a lot of promises for high‐power high‐frequency device applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and catalytic activity of hybrid metal/silicon nanocomposites
Authors: Polisski Sergej , Goller Bernhard , Lapkin Alexei , Fairclough Simon , Kovalev Dmitry 
Published: April 2008

AbstractIn this Letter we demonstrate that hydrogen‐terminated porous silicon (PSi) layers and powders can serve as highly efficient reductive templates for noble metal salts. The reduction results in metal nanoparticle (NP) formation in the pores of PSi. Gold NP formation has been monitored in‐situ by measuring the plasmon resonance response. Pt NPs, formed in the PSi matrix, were investigated by transmission electron microscopy and energy‐dispersive X‐ray analysis. Furthermore, hybrid Pt/PSi nanocomposites exhibit a high catalytic activity for CO oxidation.magnified imageHRTEM image of a Pt nanoparticle reduced inside the PSi matrix. Platinum lattice fringes d〈111〉 = 2.27 Å can be seen.(© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Small fetal abdominal circumference in the second trimester and subsequent low maternal plasma glucose after a glucose challenge test is associated with the delivery of a small‐for‐gestational age neonate
Authors: Bienstock J. L. , Holcroft C. J. , Althaus J. 
Published: April 2008

AbstractObjectivesTo evaluate the predictive value of a combination of the 1 h 50‐g glucose challenge test (GCT) and second‐trimester ultrasound measurement of fetal abdominal circumference (AC) in identifying patients who will go on to deliver small‐for‐gestational age (SGA) neonates. The individual predictive power of these tests has been indicated by previous studies, but this study examines the combined use of these indicators in predicting SGA.MethodsThis retrospective cohort study included 576 consecutive patients with singleton gestations examined over a 3‐year period. Patients' electronic medical records were abstracted to obtain the result of the GCT, the fetal AC measured by ultrasound examination between 18 and 22 weeks' gestation, and the birth weight. SGA and small AC were defined as birth weight or AC < 10th percentile for gestational age, according to published nomograms. A low GCT was defined as < 100 mg/dL. P < 0.05 was considered significant.ResultsThe prevalence of SGA in the study population was 8.7% (50/576). The frequency of SGA neonates was significantly higher in patients with a low GCT (27/207) in the second trimester than in those with a normal GCT (23/369) (13% vs. 6.2%, P = 0.005). Similarly, the frequency of SGA neonates was higher among patients with fetal AC < 10th percentile than among those with a normal fetal AC on second‐trimester ultrasound examination (17% vs. 8%, P = 0.08), although this difference did not reach statistical significance. Of interest, among patients with both a small fetal AC and a low GCT the incidence of SGA neonates was 32% (6/19), but there were no SGA neonates among those with a small AC and normal GCT (0/17) (P = 0.014). Among patients with a small fetal AC the sensitivity of using low GCT to predict subsequent delivery of a SGA neonate was 100%, with a specificity of 57%, positive predictive value 32% and negative predictive value 100%.ConclusionsSmall AC on routine second‐trimester anomaly sonogram should trigger a closer evaluation of maternal GCT. If the GCT is also low, more intensive surveillance for the possible development of a SGA infant is warranted. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal imaging findings in rapidly involuting congenital hemangioma of the skull
Authors: Elia D. , Garel C. , Enjolras O. , Vermouneix L. , Soupre V. , Oury J.‐F. , Guibaud L. 
Published: April 2008

AbstractWe report two cases of rapidly involuting congenital hemangioma (RICH) of the skull diagnosed in the third trimester of gestation, and also present a brief review of the literature. In both of our cases ultrasound examination showed a soft tissue vascular mass of the skull with a specific sonographic finding: a thin hyperechogenic line over the lesion and continuous with the calvaria, suggesting a subperiosteal origin and possibly accounting for a mass effect on the underlying skull. This was slight in one case and marked in the other (and associated with involvement of the calvaria). On prenatal T2‐weighted magnetic resonance imaging, the signal of each of the lesions was less marked than the hypersignal encountered in the postnatal period. Postnatal clinical and radiological follow‐up over the first few months after delivery confirmed the diagnosis of RICH in each case by demonstrating a significant decrease in the size of the tumor and regression of the vascular component, with complete involution of the lesion within a year. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Effects of additives on fusion parameters of rigid PVC formulations
Authors: Moghri M. , Garmabi H. , Akbarian M. 
Published: April 2008

AbstractThe effects of varying amounts of tribasic lead sulfate (TBLS), dibasic lead stearate (DBLS), neutral lead stearate (NLS), calcium stearate (Ca.St.), stearic acid (St.Ac.), and paraffin wax (PW) on the fusion properties of a rigid PVC formulation were investigated. The materials showed varying effects on fusion. Thus, fusion time was lowered and fusion factor increased by TBLS, DBLS, and Ca.St., while the reverse was true with NLS, St.Ac., and PW. The behavior of the materials is discussed in terms of their effects on the transformation of PVC grains. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.
Vitamin D deficiency and low bone status in adult female garment factory workers in Bangladesh
Authors: Islam Md Zahirul , Shamim Abu Ahmed , Kemi Virpi , Nevanlinna Antti , Akhtaruzzaman Mohammad , Laaksonen Marika , Jehan Atia H. , Jahan Khurshid , Khan Habib Ullah , Lamberg-Allardt Christel 
Published: April 2008

The manufacture of garments is the main industry in Bangladesh and employs 1·6 million female workers. Due to the indoor lifestyle and low dietary intake of calcium, we hypothesised that they are at risk of low vitamin D and bone mineral status. Two hundred female garment workers (aged 18–36 years) were randomly selected. Serum 25-hydroxyvitamin D (S-25OHD), serum intact parathyroid hormone (S-iPTH), serum calcium (S-Ca), serum phosphate (S-P) concentration and serum alkaline phosphatase activity (S-ALP) were measured from fasting samples. Bone indexes of hip and spine were measured by dual-energy X-ray absorptiometry. The mean S-25OHD (36·7 nmol/l) was low compared to that recommended for vitamin D sufficiency. About 16 % of the subjects were found to be vitamin D-deficient (S-25OHD < 25 nmol/l). We observed a high prevalence (88·5 %) of vitamin D insufficiency (S-25OHD < 50 nmol/l) as well as a significant inverse relationship between S-25OHD and S-iPTH (r − 0·25, P ≤ 0·001). A decrease in S-25OHD ( < 38 nmol/l) and an increase in S-iPTH (>21 ng/l) was associated with progressive reduction in bone mineral density at the femoral neck and lumbar spine. According to the WHO criteria, the mean T-score of the femoral neck and lumbar spine of the subjects were within osteopenic range. We observed that subjects with a bone mineral density T-score < − 2·5 had a trend of lower values of BMI, waist–hip circumference, mid-upper-arm circumference, S-25OHD and higher S-iPTH and S-ALP. The high prevalence of hypovitaminosis D and low bone mineral density among these subjects are indicative of higher risk for osteomalacia or osteoporosis and fracture.
THE CONSTANT DEMAND OF THE FRENCH: THE MASCARENE SLAVE TRADE AND THE WORLDS OF THE INDIAN OCEAN AND ATLANTIC DURING THE EIGHTEENTH AND NINETEENTH CENTURIES
Authors: ALLEN RICHARD B. 
Published: April 2008

ABSTRACTAnalysis of an inventory of 641 slaving voyages involving Mauritius and Réunion between 1768 and 1809 reveals that the Mascarene Islands were at the center of a substantial and dynamic regional slave trading network that also reached into the Americas in ways that raise questions about the relationship between the ‘worlds’ of the Indian Ocean and the Atlantic. The fact that colonial, as well as metropolitan, merchant capital underwrote Mascarene-based slave trading ventures raises additional questions about the role of locally generated and/or non-Western capital in financing the movement of slave, and ultimately ‘free’, labor throughout the eighteenth- and nineteenth-century colonial world.
Outbreaks of noroviral gastroenteritis in Florida, 2006–2007
Authors: DOYLE T. J. , STARK L. , HAMMOND R. , HOPKINS R. S. 
Published: April 2008

SUMMARYNoroviruses are an important cause of sporadic cases and outbreaks of acute gastroenteritis. During 2006–2007, widespread increases in acute gastroenteritis outbreaks consistent with norovirus were observed in the United States. We conducted a statewide survey to characterize norovirus outbreak activity in Florida during a 1-year period. From July 2006 to June 2007, 257 outbreaks of norovirus gastroenteritis were identified in 39 of Florida's 67 counties. About 44% of outbreaks were laboratory confirmed as norovirus and 93% of these were due to genogroup GII. About 63% of outbreaks occurred in long-term care facilities and 10% of outbreaks were classified as foodborne. The median number of ill persons per outbreak was 24, with an estimated total of 7880 ill persons. During the study period, norovirus outbreak activity in Florida was widespread, persistent, and consistent with increased activity observed in other parts of the country.
Obesity Indices and Self‐Reported Functional Health in Men and Women in the EPIC‐Norfolk
Authors: Myint Phyo K. , Welch Ailsa A. , Luben Robert N. , Wainwright Nicholas W.J. , Surtees Paul G. , Bingham Sheila A. , Wareham Nicholas J. , Smith Richard D. , Harvey Ian M. , Khaw Kay‐Tee 
Published: April 2008

AbstractObjective: To investigate the association between two indices of obesity, BMI and waist‐to‐hip ratio (WHR), and self‐reported physical and mental functional health.Research Methods and Procedures: We examined the relationship between obesity indices and self‐reported physical and mental functional health measured by the Anglicized version of the Short‐Form 36‐item questionnaire in a population‐based cross sectional study of 16, 806 men and women 40 to 79 years old living in the general community in Norfolk, United Kingdom.Results: Higher BMI and WHR were both independently associated with poorer self‐reported physical functional health in men and women. The effect of BMI was greater in women compared with men, and the effect of WHR was greater in men compared with women, for poor physical functional health. Higher WHR but not BMI was associated with lower mental functional health in men and women.Discussion: High BMI and WHR seem to be adversely related to self‐perceived functional health in both men and women, although their relative impacts seem to differ by sex. Our findings also highlight the importance of using WHR in addition to BMI in assessing the impact of obesity on health outcome.
Correlates of BMI Misreporting among Apparently Healthy Individuals: The ATTICA Study
Authors: Yannakoulia Mary , Panagiotakos Demosthenes B. , Pitsavos Christos , Stefanadis Christodoulos 
Published: April 2008

AbstractObjective: The aim of this study was to investigate correlates of misreporting in BMI, based on self‐reported weight and height, in a randomly selected population sample of Greek adults and to evaluate the effect of obesity status misclassification on the associations between obesity and disease.Research Methods and Procedures: During 2001 to 2002, we randomly enrolled 1514 men (18 to 87 years old) and 1528 women (18 to 89 years old) from the Attica area, Greece; the sampling was stratified by the age‐sex distribution of the region. Various sociodemographic, clinical, and psychological characteristics were self‐reported, and weight and height were measured and recorded in all participants.Results: The proportions of true positives and true negatives for correct obesity status identification were 62% and 97%, respectively. Women were 9 times more likely to be under‐reporters than men, whereas men were 7.5 times more likely to be over‐reporters. A 10‐year increase in age was associated with a 48% higher likelihood of being an under‐reporter and 26% lower likelihood of being an over‐reporter, irrespective of sex and other characteristics of the participants. Clinical status, such as the presence of hypertension and diabetes, was associated with under‐reporting of body weight. Furthermore, the use of self‐reported data may substantially exaggerate associations between obesity and obesity‐related diseases, such as diabetes, hypercholesterolemia, and hypertension.Discussion: The study indicates that, apart from age and sex, disease status may be another factor that influences misreporting of obesity status, with diabetic and hypertensive people to be more likely to under‐report their overweight. Use of self‐reported data may bias obesity—disease associations.
Socioeconomic Status in Relation to Obesity and Abdominal Obesity in Korean Adults: A Focus on Sex Differences
Authors: Yoon Yeong Sook , Oh Sang Woo , Park Hye Soon 
Published: April 2008

AbstractObjective: We examined the relationship between income and education level with BMI and waist circumference to provide further understanding of the relationship between socioeconomic status and obesity and to identify the presence of sex differences.Research Methods and Procedures: A total of 7962 people ≥20 years of age (3597 men; 4365 women) who participated in the 1998 Korean National Health and Nutrition Examination Survey provided data including height, weight, waist circumference, education, and income level. We examined adjusted BMI and waist circumference according to level of income and education and the association between income and education with obesity and abdominal obesity by multiple logistic regression analysis.Results: In men, significant dose‐response relationships were noted between income and obesity (trend, p < 0.05) and abdominal obesity (trend, p < 0.05). Compared with the lowest income group, the adjusted odds ratios (ORs) (95% confidence interval) of the highest income group for obesity and abdominal obesity were 1.65 (1.18 to 2.32) and 1.37 (0.94 to 1.98), respectively. However, income was not associated with obesity or abdominal obesity in the fully adjusted models in women. With regard to education, women showed significantly decreased ORs, with inverse trends for obesity and abdominal obesity across all education levels. Compared with the lowest education group, the adjusted ORs (95% confidence interval) for obesity and abdominal obesity were 0.66 (0.57 to 0.76) and 0.40 (0.35 to 0.45), respectively, among women with 7 to 12 years of schooling and 0.27 (0.21 to 0.34) and 0.15 (0.12 to 0.18), respectively, among women with 13 or more years of schooling.Discussion: Socioeconomic difference has a considerable impact on the prevalence of obesity among the Korean population, and the patterns differ substantially across sex.
Population‐Based Analysis of Obesity and Workforce Participation
Authors: Klarenbach Scott , Padwal Raj , Chuck Anderson , Jacobs Philip 
Published: April 2008

AbstractObjective: To describe the relationship between obesity class and workforce participation and the influence of demographic, socioeconomic, and comorbid disease states on this relationship using population‐based Canadian data.Research Methods and Procedures: Responses from 73, 531 adults surveyed in the Canadian Community Health Survey 2000 to 2001 who provided complete information regarding variables of interest were analyzed. Workforce participation was defined as individuals reporting that they held and were present at a job or business in the week before survey administration. The association between obesity and workforce participation was explored using logistic regression after adjusting for demographic, socioeconomic, and obesity‐related comorbidities.Results: In univariate analysis, obese individuals had lower odds of participating in the workforce. In the fully adjusted model, increasing obesity was associated with decreasing odds of workforce participation, with Class I, II, and III obesity having odds ratios (95% confidence interval) of 0.94 (0.89 to 0.99), 0.85 (0.77 to 0.94), and 0.66 (0.57 to 0.78), respectively. Obese individuals were also less likely to be employed and more likely to be absent from work.Discussion: Obesity is associated with lower workforce participation. This association appears to be independent of associated comorbidity and sociodemographic factors. These results indicate that the economic impact of obesity alone on workforce productivity is larger than previous reports suggest.
Reducing Overweight through a Multidisciplinary School‐based Intervention
Authors: Spiegel Samuel A. , Foulk David 
Published: April 2008

AbstractObjective: This study sought to evaluate the effectiveness of a multidisciplinary elementary school—based intervention entitled Wellness, Academics & You. The primary areas of impact examined were BMI, consumption of fruits and vegetables, and physical activity.Research Methods and Procedures: The sample consisted of 1013 students in fourth and fifth grades from 69 classes in four states. Intervention and comparison classes were randomly selected at each school. Intervention teachers participated in workshops on the intervention and received program materials. BMI was calculated for baseline and post‐data points based on measured height and weight collected by trained research teams. Baseline surveys were administered by the students’ teacher in the presence of one of the research team members and collected.Results: SPSS (SPSS, Inc., Chicago, IL) analysis of post‐data shows significant positive shifts (p = 0.01) in BMI in the intervention group compared with the comparison group. Notable increases in the consumption of fruits and vegetables and increased physical activity levels were reported in the intervention group.Discussion: Data from this study indicate that this school‐based program may contribute to the reduction of overweight and obesity. The intervention was well received by the classroom teachers and shows promise for a school‐based obesity prevention initiative. This program has shown the capacity to effect positive changes in BMI through consumption of fruits and vegetables and physical activity. The evaluation covered a limited time period and, therefore, warrants additional studies to determine whether long‐term program fidelity will result in continued improvement.