bluuebunny/crossref_metadata_2025 huggingface dataset:
Higher Protein Intake Preserves Lean Mass and Satiety with Weight Loss in Pre‐obese and Obese Women
Authors: Leidy Heather J. , Carnell Nadine S. , Mattes Richard D. , Campbell Wayne W.
Published: July 2008

Objective: To examine the effects of dietary protein and obesity classification on energy‐restriction‐induced changes in weight, body composition, appetite, mood, and cardiovascular and kidney health.

Research Methods and Procedures: Forty‐six women, ages 28 to 80, BMI 26 to 37 kg/m2, followed a 12‐week 750‐kcal/d energy‐deficit diet containing higher protein (HP, 30% protein) or normal protein (NP, 18% protein) and were retrospectively subgrouped according to obesity classification [pre‐obese (POB), BMI = 26 to 29.9 kg/m2; obese (OB), BMI = 30 to 37 kg/m2).

Results: All subjects lost weight, fat mass, and lean body mass (LBM; p < 0.001). With comparable weight loss, LBM losses were less in HP vs. NP (−1.5 ± 0.3 vs. −2.8 ± 0.5 kg; p < 0.05) and POB vs. OB (−1.2 ± 0.3 vs. −2.9 ± 0.4 kg; p < 0.005). The main effects of protein and obesity on LBM changes were independent and additive; POB‐HP lost less LBM vs. OB‐NP (p < 0.05). The energy‐restriction‐induced decline in satiety was less pronounced in HP vs. NP (p < 0.005). Perceived pleasure increased with HP and decreased with NP (p < 0.05). Lipid‐lipoprotein profile and blood pressure improved and kidney function minimally changed with energy restriction (p < 0.05), independently of protein intake.

Discussion: Consuming a higher‐protein diet and accomplishing weight loss before becoming obese help women preserve LBM. Use of a higher‐protein diet also improves perceptions of satiety and pleasure during energy restriction.
The Validity of Obesity Based on Self‐reported Weight and Height: Implications for Population Studies
Authors: Nyholm Maria , Gullberg Bo , Merlo Juan , Lundqvist‐Persson Cristina , Råstam Lennart , Lindblad Ulf
Published: July 2008

Objective: To validate self‐reported information on weight and height in an adult population and to find a useful algorithm to assess the prevalence of obesity based on self‐reported information.

Research Methods and Procedures: This was a cross‐sectional survey consisting of 1703 participants (860 men and 843 women, 30 to 75 years old) conducted in the community of Vara, Sweden, from 2001 to 2003. Self‐reported weight, height, and corresponding BMI were compared with measured data. Obesity was defined as measured BMI ≥ 30 kg/m2. Information on education, self‐rated health, smoking habits, and physical activity during leisure time was collected by a self‐administered questionnaire.

Results: Mean differences between measured and self‐reported weight were 1.6 kg (95% confidence interval, 1.4; 1.8) in men and 1.8 kg (1.6; 2.0) in women (measured higher), whereas corresponding differences in height were −0.3 cm (−0.5; −0.2) in men and −0.4 cm (−0.5; −0.2) in women (measured lower). Age and body size were important factors for misreporting height, weight, and BMI in both men and women. Obesity (measured) was found in 156 men (19%) and 184 women (25%) and with self‐reported data in 114 men (14%) and 153 women (20%). For self‐reported data, the sensitivity of obesity was 70% in men and 82% in women, and when adjusted for corrected self‐reported data and age, it increased to 81% and 90%, whereas the specificity decreased from 99% in both sexes to 97% in men and 98% in women.

Discussion: The prevalence of obesity based on self‐reported BMI can be estimated more accurately when using an algorithm adjusted for variables that are predictive for misreporting.
Calcium and 1,25‐Dihydroxyvitamin D3 Regulation of Adipokine Expression
Authors: Sun Xiaocun , Zemel Michael B.
Published: July 2008

Objective: Obesity is associated with elevated oxidative stress and low‐grade systemic inflammation. We have demonstrated recently that 1α,25‐(OH)2‐D3 promotes reactive oxygen species production in cultured adipocytes, whereas suppression of 1α,25‐(OH)2‐D3 by increasing dietary calcium down‐regulates diet‐induced oxidative stress in aP2‐agouti transgenic mice. However, whether the anti‐obesity effect of dietary calcium plays a role in regulation of obesity‐associated inflammation is not clear.

Research Methods and Procedures: We investigated the role of dietary calcium in the regulation of inflammatory cytokine production in aP2‐agouti transgenic mice fed low‐ and high‐calcium obesigenic diets and in the modulation of cytokine production by 1α,25‐(OH)2‐D3 in cultured murine and human adipocytes.

Results: The high‐calcium diet inhibited the expression of pro‐inflammatory factors tumor necrosis factor α and interleukin (IL)‐6 by 64% and 51%, respectively (p < 0.001), in visceral fat, stimulated the expression of the anti‐inflammatory factors IL‐15 and adiponectin by 52% (p = 0.001) and 54% (p = 0.025), respectively, in visceral fat, and induced a 2‐fold increase in IL‐15 expression in soleus muscle (p = 0.01) compared with litter mate controls on a low‐calcium diet. 1α,25‐(OH)2‐D3 also markedly stimulated the expression of tumor necrosis factor α (p < 0.001) and IL‐6 (p = 0.016) in differentiated 3T3‐L1 adipocytes and increased IL‐6 (p = 0.004) and IL‐8 (p < 0.001) production in differentiated human adipocytes. These effects were blocked by calcium channel antagonism with nifedipine.

Discussion: These data demonstrate that 1α,25‐(OH)2‐D3 favors inflammatory cytokine expression and inhibits anti‐inflammatory cytokine expression; accordingly, suppression of 1α,25‐(OH)2‐D3 by dietary calcium inhibits adipocyte‐derived inflammation associated with obesity.
Vitamin E Supplementation and Plasma 8‐Isoprostane and Adiponectin in Overweight Subjects
Authors: Sutherland Wayne H. F. , Manning Patrick J. , Walker Robert J. , De Jong Sylvia A. , Ryalls Anne R. , Berry Elizabeth A.
Published: July 2008

Objective: Isoprostanes are a marker of oxidant stress and atherosclerotic risk, and plasma concentrations are elevated in obesity. Adiponectin is a regulator of insulin sensitivity, and low circulating levels are associated with oxidant stress and obesity. The aim of this study was to determine the effect of vitamin E supplementation on plasma concentrations of 8‐isoprostane and adiponectin in overweight/obese subjects.

Research Methods and Procedures: The study was a 6‐month, randomized, double‐blind, placebo‐controlled trial in 80 overweight subjects (60 women and 20 men, BMI >27 kg/m2). Exclusion criteria were serious illness, smoking, or taking antioxidant supplements. Participants were randomized to receive 800 IU/d natural vitamin E (n = 39) or placebo (n = 41) for 3 months with an increase in the dose to 1200 IU/d for a further 3 months. Plasma 8‐isoprostane and adiponectin concentrations were measured at baseline and 3 and 6 months.

Results: During 6 months of supplementation with vitamin E, plasma vitamin E concentration increased significantly (p < 0.001) by 76%, and plasma 8‐isoprostane concentrations decreased significantly (−11%, p = 0.03), whereas plasma adiponectin concentrations did not change significantly.

Discussion: These findings suggest that supplementation with high‐dose vitamin E decreases systemic oxidative stress and 8‐isoprostane concentrations in overweight/obese individuals. A decrease in plasma 8‐isoprostane has the potential to reduce risk of cardiovascular disease in obesity.
Heritability of Determinants of the Metabolic Syndrome among Healthy Arabs of the Oman Family Study
Authors: Bayoumi Riad A. , Al‐Yahyaee Saeed A.S. , Albarwani Sulayma A. , Rizvi Syed G. , Al‐Hadabi Saleh , Al‐Ubaidi Firial F. , Al‐Hinai Ali T. , Al‐Kindi Mohammed N. , Adnan Haleema T. , Al‐Barwany Hameeda S. , Comuzzie Antony G. , Cai Guowen , Lopez‐Alvarenga Juan C. , Hassan Mohammed O.
Published: July 2008

The metabolic syndrome, as defined by the International Diabetes Federation, was investigated in five large, extended, highly consanguineous, healthy Omani Arab families of a total of 1277 individuals. Heritability (h2) of the phenotypic abnormalities that make up the syndrome and other related traits was estimated by variance decomposition method using SOLAR software. The overall prevalence of the syndrome was 23%. The prevalence of abnormalities making the syndrome in a descending order were: obligatory waist circumference, hypertension, raised fasting blood glucose, low serum high‐density lipoprotein (HDL), and raised serum triglycerides (TGs). Highly significant, but widely spread, h2 values were obtained for: height (0.68), weight (0.68), BMI (0.68), serum HDL (0.63), serum leptin (0.55), percentage body fat (0.53), total serum cholesterol (0.53), fasting serum insulin (0.51), homeostasis model assessment‐insulin resistance index (0.48), serum TG (0.43), waist circumference (0.40), diastolic blood pressure (0.38), and 2‐hour glucose level (0.17), whereas for the metabolic syndrome itself, h2 was 0.38. The wide spread of h2 results (0.07 to 0.68) indicates that some determinants, such as weight, BMI, and HDL level, are under significant genetic influence among the Omani Arabs. Other determinants such as insulin resistance, abdominal obesity, diastolic blood pressure, and TG levels seem to be more environmentally driven.
The Impact of Central Obesity as a Prerequisite for the Diagnosis of Metabolic Syndrome
Authors: Khoo Chin Meng , Liew Choon Fong , Chew Suok Kai , Tai E. Shyong
Published: July 2008

Objective: To compare the prevalence of metabolic syndrome (MS) defined according to the American Heart Association (AHA)/National Heart Lung and Blood Institute (NHLBI) and the International Diabetes Federation (IDF) and to determine the effect of the presence of central obesity on the phenotype (insulin resistance and other cardiovascular risk factors) associated with MS.

Research Methods and Procedures: We studied 4723 Chinese, Malays, and Asian Indians living in Singapore. Each individual was categorized according to the five criteria for MS as defined by the AHA/NHLBI and the IDF. The population was categorized according to the presence of three or more criteria and then further subcategorized according to the presence or absence of central obesity. Characteristics of each group were compared using ANOVA and the χ2 test.

Results: MS was present in 20.2% (IDF) and 26.9% (AHA/NHLBI) of the population. Of the population, 6.7% exhibited three or more features of MS without central obesity. Use of the IDF definition, which requires central obesity, is associated with greater insulin resistance but similar levels of other cardiovascular disease risk factors than the use of the AHA/NHLBI definition, which does not require central obesity.

Discussion: In this Southeast Asian population, the IDF and the AHA/NHLBI definitions of MS identify different segments of the MS population. The IDF definition may be more appropriate for the identification of those with insulin resistance and increased risk of type 2 diabetes. In contrast, the AHA/NHLBI definition may better identify those at increased risk of cardiovascular disease.
Role of Epidermal Growth Factor and ErbB2 Receptors in 3T3‐L1 Adipogenesis
Authors: Harrington Molly , Pond‐Tor Sunthorn , Boney Charlotte M.
Published: July 2008

Objective: Epidermal growth factor (EGF) stimulates proliferation in 3T3‐L1 preadipocytes, but EGF action in differentiation is less clear. EGF promotes differentiation at concentrations <1 nM but inhibits differentiation at higher concentrations, suggesting a dual role in adipogenesis. We hypothesized that differences in EGF receptor activation and downstream signaling mediate distinct biological effects of EGF at low vs. high abundance.

Research Methods and Procedures: We compared the effects of low (0.1 nM) vs. high (10 nM) EGF on the activation of EGF receptors, proximal signaling molecules Src and Shc, and the downstream mitogen‐activated protein kinase (MAPK) pathways extracellular regulated kinase (ERK) and p38 in proliferating and differentiated 3T3‐L1 cells.

Results: Both low and high EGF activated ERK and p38 in preadipocytes. Src inhibitors PP1 and PP2 blocked ERK and p38 activation by low but not high EGF, and only high EGF increased Shc phosphorylation. Selective inhibition of the EGF receptor (EGFR) with AG1478 blocked ERK and p38 activation at both concentrations; however, selective inhibition of the ErbB2 receptor (EB2R) with AG825 or small interfering RNA (siRNA) blocked low but not high EGF activation of ERK and p38. Coimmunoprecipitation of EGFR with EB2R and Src was observed with low EGF in preadipocytes but at both concentrations in adipocytes. EB2R inhibition during differentiation decreased p38 activity and peroxisome proliferator‐activated receptor γ (PPARγ) abundance.

Discussion: Our results show that EGFR homodimers mediate action of EGF at high abundance, but at low abundance, EGF promotes differentiation through EGFR/EB2R heterodimer activation of Src and p38. These results may partially explain the observations that high EGF concentrations inhibit, whereas low concentrations support, preadipocyte differentiation.
Meal Pattern of Male Rats Maintained on Histidine‐, Leucine‐, or Tyrosine‐Supplemented Diet
Authors: Bassil Maya S. , Hwalla Nahla , Obeid Omar A.
Published: July 2008

Objective: Food intake is known to be affected by macronutrient composition of the diet, and protein manipulation has been reported to alter food intake, but the effect of individual amino acids on eating behavior has not been fully studied. This study investigated the effect of diet supplementation with three individual amino acids on meal pattern in male rats.

Research Methods and Procedures: Thirty‐two Sprague‐Dawley rats were randomly divided into four equal groups and fed control diet or histidine (5%)‐, leucine (5%)‐, or tyrosine (5%)‐supplemented diet for 2 weeks and were monitored for their meal pattern.

Results: Total food intake and feeding rate of the different groups were not affected, although other components of meal pattern were altered. Histidine supplementation reduced diurnal meal size by 42% (p < 0.05), whereas that of leucine increased nocturnal meal size by ∼35% (p < 0.05). Tyrosine supplementation increased food intake of the nocturnal period and decreased that of the diurnal period. Both histidine and tyrosine supplementation elevated fasting plasma insulin levels and suppressed fasting glucose significantly.

Discussion: Individual amino acids were found to alter meal pattern differently. Further investigations are required to dissect the involvement of central and peripheral factors in these alterations.
NIH ImageJ and Slice‐O‐Matic Computed Tomography Imaging Software to Quantify Soft Tissue
Authors: Irving Brian A. , Weltman Judy Y. , Brock David W. , Davis Christopher K. , Gaesser Glenn A. , Weltman Arthur
Published: July 2008

Objective: To compare reliability and limits of agreement of soft tissue cross‐sectional areas obtained using Slice‐O‐Matic and NIH ImageJ medical imaging software packages.

Research Methods and Procedures: Abdominal and midthigh images were obtained using single‐slice computed tomography. Two trained investigators analyzed each computed tomography image in duplicate. Adipose tissue and skeletal muscle cross‐sectional areas (centimeters squared) were calculated using standard Hounsfield unit ranges (adipose tissue: −190 to −30 and skeletal muscle: −29 to 150). Regions of interest included abdominal total area, total fat area, subcutaneous fat area, visceral fat area (AVF), and right and left thigh total area, fat area, and skeletal muscle area.

Results: For all images, intra‐investigator coefficients of variation ranged from 0.2% to 3.4% and from 0.4% to 5.6% and inter‐investigator coefficients of variation ranged from 0.9% to 4.8% and 0.2% to 2.6% for Slice‐O‐Matic and NIH ImageJ, respectively, with intra‐ and inter‐investigator coefficients of reliability of R2 = 0.99. Mean AVF values for investigators A and B ranged from 168 to 170 cm2 using Slice‐O‐Matic and NIH ImageJ. Bland‐Altman analyses revealed that Slice‐O‐Matic and NIH ImageJ results were comparable. The mean differences (95% confidence intervals) between the AVF cross‐sectional areas obtained using the Slice‐O‐Matic and NIH ImageJ medical imaging software were +2.5 cm2 (−5.7, +10.8 cm2) or +1.4% (−3.4%, +6.4%).

Discussion: These findings show that both the Slice‐O‐Matic and NIH ImageJ medical imaging software systems provide reliable measurements of adipose tissue and skeletal muscle cross‐sectional areas.
Secular Trends of Obesity and Cardiovascular Risk Factors in a Mediterranean Population
Authors: Schröder Helmut , Elosua Roberto , Vila Joan , Marti Helena , Covas Maria Isabel , Marrugat Jaume
Published: July 2008

Objective: To evaluate time trends of obesity, abdominal obesity, and cardiovascular risk factors (CRFs) according to BMI and waist circumference (WC) categories in a Mediterranean population.

Research Methods and Procedures: Subjects were Spanish men (n = 2383) and women (n = 2525) 25 to 74 years old, examined in 1994 to 1995 and 1999 to 2000 in two independent population‐based cross‐sectional surveys in the northeast of Spain. Lifestyle measures, CRFs, and anthropometric variables were analyzed.

Results: Over the 5 years of the study, mean age‐standardized BMI increased by 1.0 units in men and by 0.8 units in women. At the same time the prevalence of obesity increased from 15.4% to 21.9% in men and from 15.4% to 21.4% in women. An upward trend was observed for WC and abdominal obesity (WC > 102 cm in men and WC > 88 cm in women) only in men. The proportion of men and women with hypercholesterolemia, diabetes, and low high‐density lipoprotein‐cholesterol plasma concentration remained stable within BMI and WC categories. The proportion of hypertension and smoking in obese men significantly increased from 1995 to 2000.

Discussion: The 5‐year increase in BMI and WC is of considerable magnitude in the present population, although several CRFs remained stable within BMI and WC categories.
Effect of Weight Loss on Predicted Cardiovascular Risk: Change in Cardiac Risk After Bariatric Surgery
Authors: Batsis John A. , Romero‐Corral Abel , Collazo‐Clavell Maria L. , Sarr Michael G. , Somers Virend K. , Brekke Lee , Lopez‐Jimenez Francisco
Published: July 2008

Objective: Our goal was to assess the effect of bariatric surgery on cardiovascular risk estimations of preventable, long‐term adverse outcomes.

Research Methods and Procedures: We performed a population‐based, historical cohort study between 1990 and 2003 of 197 consecutive patients from Olmsted County, MN, with Class II to III obesity (defined as BMI ≥35 kg/m2) treated with Roux‐en‐Y gastric bypass and 163 non‐operative patients assessed in a weight‐reduction program. We used the observed change in cardiovascular risk factors and risk models derived from data from the National Health and Nutrition Examination Survey (NHANES) I and the NHANES I Epidemiological Follow‐up Study (NHEFS) to calculate the predicted impact on cardiovascular events and mortality for the operative and non‐operative groups.

Results: Mean follow‐up was 3.3 years. Hypertension, diabetes, and dyslipidemia all improved after bariatric surgery. The estimated 10‐year risk for cardiovascular events for the operative group decreased from 37% at baseline to 18% at follow‐up, while the estimated risk for the non‐operative group did not change from 30% at baseline to 30% at follow‐up. Risk modeling to predict 10‐year outcomes estimated 4 overall deaths and 16 cardiovascular events prevented by bariatric surgery per 100 patients compared with the non‐operative group.

Conclusions: Bariatric surgery induces an improvement in cardiovascular risk factors in patients with Class II to III obesity. Weight loss predicts a major, 10‐year reduction in cardiovascular events and deaths. Bariatric surgery should be considered as an alternative approach to reduce cardiovascular risk in patients with Class II to III obesity.
Volumetric Assessment of Epicardial Adipose Tissue With Cardiovascular Magnetic Resonance Imaging
Authors: Flüchter Stephan , Haghi Dariush , Dinter Dietmar , Heberlein Wolf , Kühl Harald P. , Neff Wolfgang , Sueselbeck Tim , Borggrefe Martin , Papavassiliu Theano
Published: July 2008

Objective: Previous studies determined the amount of epicardial fat by measuring the right ventricular epicardial fat thickness. However, it is not proven whether this one‐dimensional method correlates well with the absolute amount of epicardial fat. In this prospective study, a new cardiovascular magnetic resonance imaging (CMR) method using the three‐dimensional summation of slices method was introduced to assess the total amount of epicardial fat.

Research Methods and Procedures: CMR was performed in 43 patients with congestive heart failure and in 28 healthy controls. The absolute amount of epicardial fat was assessed volumetrically in consecutive short‐axis views by means of the modified Simpson's rule. Additionally, the right ventricular epicardial fat thickness was measured in two different imaging planes: long‐axis view (EFT‐4CV) and consecutive short‐axis views (EFT‐SAX).

Results: Using the volumetric approach, patients with congestive heart failure had less epicardial fat mass than controls (51 g vs. 65 g, p = 0.01). This finding was supported by EFT‐SAX (2.9 mm vs. 4.3 mm, p < 0.0001) but not by EFT‐4CV (3.5 mm vs. 3.8 mm, p = not significant). Epicardial fat mass correlated moderately with EFT‐SAX in both groups (r = 0.466, p = 0.012 in controls and r = 0.590, p < 0.0001 in patients) and with EFT‐4CV in controls (r = 0.387, p = 0.042). There were no significant differences between EFT‐4CV and EFT‐SAX in controls (4.3 mm vs. 3.8 mm, p = 0.240). However, in the heart failure group, EFT‐4CV was significantly higher compared with EFT‐SAX (3.5 mm vs. 2.9 mm, p = 0.003). Interobserver variability and reproducibility were superior for the volumetric approach compared with thickness measurements.

Discussion: Quantitative assessment of epicardial fat mass using the CMR‐based volumetric approach is feasible and yields superior reproducibility compared with conventional methods.
Youths’ Perceptions of Overweight‐related Prevention Counseling at a Primary Care Visit
Authors: Taveras Elsie M. , Sobol Arthur M. , Hannon Cynthia , Finkelstein Daniel , Wiecha Jean , Gortmaker Steven L.
Published: July 2008

Objective: We examined youths’ report of receiving specific overweight‐related preventive counseling and perceived readiness to adopt nutrition and physical activity behaviors recommended by their clinicians.

Research Methods and Procedures: We surveyed 324 youth 10 to 18 years old who had a physical exam within the past year. The survey included questions on height, weight, race/ethnicity, mother's education, and topics they discussed with their clinician during their visit. We used multivariable analyses to examine whether weight status and sociodemographic characteristics were predictors of which youth received counseling from their clinicians and which youth were ready to change.

Results: The mean (standard deviation) age of participants was 13.7 (1.8) years; 54% were black, and 22% were Hispanic. Less than one‐half of participants reported discussing sugar‐sweetened beverages [38%; 95% confidence interval (CI), 32% to 43%] or television viewing (41%; 95% CI, 36% to 47%) with their clinicians. In multivariable analyses adjusting for participant's age, sex, race/ethnicity, overweight status, and mother's educational attainment, youth whose mothers lacked education beyond high school were significantly less likely to report receiving counseling on any overweight‐specific topic including television viewing [odds ratio (OR), 0.46; 95% CI, 0.27, 0.79], sugar‐sweetened beverage (OR, 0.47; 95% CI, 0.28, 0.80), and fast food consumption (OR, 0.54; 95% CI, 0.32, 0.92). In addition, youth 10 to 14 years old were more likely than those 15 to 18 years old to report they would try to change their television viewing (OR, 4.10; 95% CI, 1.78, 9.44) if recommended by their clinician.

Discussion: Youth report infrequently receiving counseling on specific overweight prevention topics during routine primary care visits. Our findings suggest that greater efforts may be needed to reduce social class disparities in overweight prevention counseling and that counseling to prevent overweight in youth may be more acceptable to younger children.
The Association Between Birth Weight and Visceral Fat in Middle‐age Adults
Authors: McNeely Marguerite J. , Fujimoto Wilfred Y. , Leonetti Donna L. , Tsai Elaine C. , Boyko Edward J.
Published: July 2008

Objective: Low birth weight, a proxy for fetal underdevelopment, is associated with increased risk of developing type 2 diabetes during adulthood. Low birth weight is also associated with central obesity, but little is known about the association between birth weight and visceral adiposity. The purpose of this study is to test the hypothesis that lower birth weight is associated with increased amounts of visceral fat in middle‐age adults.

Research Methods and Procedures: This is an observational study of 91 adults (58 men and 33 women) 40 ± 6 years of age (mean ± standard deviation). Ethnicity was either Japanese American (79%) or non‐Hispanic white (21%). Birth weight was obtained from State Departments of Health. Measurements included smoking status, BMI, and visceral (intra‐abdominal) fat measured by computed tomography.

Results: Visceral fat was not associated with birth weight after adjustment for age, sex, ethnicity, BMI, or smoking status (p = 0.76). There was no evidence that the association between birth weight and visceral fat varied by age, sex, or ethnicity.

Discussion: We found no evidence that low birth weight is associated with increased visceral fat in middle‐age adults
Relationship of Visceral Adiposity to Cardiovascular Disease Risk Factors in Black and White Teens
Authors: Gutin Bernard , Johnson Maribeth H. , Humphries Matthew C. , Hatfield‐Laube Jeannie L. , Kapuku Gaston K. , Allison Jerry D. , Gower Barbara A. , Daniels Stephen R. , Barbeau Paule
Published: July 2008

Objective: We tested the hypothesis that visceral adiposity, compared with general adiposity, would explain more of the variance in cardiovascular disease (CVD) risk factors.

Research Method and Procedures: Subjects were 464 adolescents (238 black and 205 girls). Adiposity measures included visceral adipose tissue (VAT; magnetic resonance imaging), percent body fat (%BF; DXA), BMI, and waist girth (anthropometry). CVD risk factors were fasting insulin, fibrinogen, total to high‐density lipoprotein‐cholesterol ratio, triglycerides (TGs), systolic blood pressure, and left ventricular mass indexed to height2.7.

Results: After adjustment for age, race, and sex, all adiposity indices explained significant proportions of the variance in all of the CVD risk factors; %BF tended to explain more variance than VAT. Regression models that included both %BF and VAT found that both indices explained independent proportions of the variance only for total to high‐density lipoprotein‐cholesterol ratio. For TGs, the model that included both %BF and VAT found that only VAT was significant. For systolic blood pressure and left ventricular mass indexed to height2.7, anthropometric measures explained more of the variance than VAT and %BF.

Discussion: The hypothesis that visceral adiposity would explain more variance in CVD risk than general adiposity was not supported in this relatively large sample of black and white adolescents. Only for TGs did it seem that VAT was more influential than %BF. Perhaps the deleterious effect of visceral adiposity becomes greater later in life as it increases in proportion to general adiposity.
Physical Activity‐Related Energy Expenditure With the RT3 and TriTrac Accelerometers in Overweight Adults
Authors: Jacobi David , Perrin Anne‐Elisabeth , Grosman Natacha , Doré Marie‐France , Normand Sylvie , Oppert Jean‐Michel , Simon Chantal
Published: July 2008

Objective: The objective was to evaluate two accelerometers, the RT3 and the TriTrac‐R3D for their ability to produce estimates of physical activity‐related energy expenditure (PAEE) in overweight/obese adults.

Research Methods and Procedures: PAEE estimates from both accelerometers were obtained in two experiments. In Experiment 1, 13 overweight/obese subjects (BMI 34.2 ± 6.4 kg/m2) were monitored over 2 weeks in everyday life, PAEE being simultaneously measured by the doubly labeled water method (DLW). In Experiment 2, 8 overweight/obese subjects (BMI 34.3 ± 5.0 kg/m2) and 10 normal‐weight subjects (BMI 20.8 ± 2.1 kg/m2) were monitored during a treadmill walking protocol, PAEE being simultaneously measured by indirect calorimetry.

Results: In Experiment 1, there was no significant difference between methods in mean PAEE (DLW: 704 ± 223 kcal/d, RT3: 656 ± 140 kcal/d, TriTrac‐R3D 624 ± 419 kcal/d). The relative difference between methods (accelerometer vs. DLW) was −17.1% ± 16.7% for the RT3 and −20.0 ± 44.6% for the TriTrac‐R3D. Correlation for PAEE between RT3 and DLW was higher than between TriTrac‐R3D and DLW (r = 0.67, p < 0.05 and r = 0.36, p = 0.25, respectively). The 95% confidence interval (CI) (kcal/d) of the mean difference between methods was large, amounting to −385 to 145 for the RT3 and −887 to 590 for the TriTrac‐R3D. In Experiment 2, both accelerometers were sensitive to the changes in treadmill speed, with no significant difference in mean PAEE between methods in overweight/obese subjects.

Conclusions: Although both accelerometers did not provide accurate estimates of PAEE at individual levels, the data suggest that RT3 has the potential to assess PAEE at group levels in overweight/obese subjects.
The Association Between Changes in Height and Obesity in Chilean Preschool Children: 1996–2004
Authors: Stanojevic Sanja , Kain Juliana , Uauy Ricardo
Published: July 2008

Objectives: To establish the association between changes in height and prevalence of obesity between 1996 and 2004 in Chilean preschool children.

Research Methods and Procedures: Children registered in the Junta Nacional de Jardines Infantiles (JUNJI) preschool program were routinely measured three times a year and in consecutive years. Two indices [weight‐for‐height z‐scores (WHZ) and BMI centiles] were used to define obesity. Height‐for‐age z‐scores (HAZ) were used to define stature. Generalized estimating equations were used to describe the relationship between stature and obesity while controlling for repeated measurements in children.

Results: The prevalence of obesity in Chilean preschool children has remained relatively constant over the past 9 years when either index is used. The prevalence of stunted (HAZ ≤2) children has decreased, while the proportion of children who are tall (HAZ >2) has increased. Using WHZ to define obesity, stunted children do not seem to be at increased risk of obesity when compared with children of normal height. Tall children were strongly protected from obesity when either criterion was used to define obesity.

Discussion: The lack of association between stunting and obesity using WHZ ≥2 likely reflects the fact that Chile is in the post‐transitional phase of the nutrition transition, and stunting is no longer a risk factor for obesity; however, the associations observed between stunting and BMI suggest that either WHZ or BMI, or both, are inaccurate criteria to define overweight.

Conclusions: There is a unique relationship between stature and obesity in preschool children that is different from that observed in older children in the same population.
Estimating Abdominal Adipose Tissue with DXA and Anthropometry
Authors: Hill Alison M. , LaForgia Joe , Coates Alison M. , Buckley Jonathan D. , Howe Peter R.C.
Published: July 2008

Objective: To identify an anatomically defined region of interest (ROI) from DXA assessment of body composition that when combined with anthropometry can be used to accurately predict intra‐abdominal adipose tissue (IAAT) in overweight/obese individuals.

Research Methods and Procedures: Forty‐one postmenopausal women (age, 49 to 66 years; BMI, 26 to 37 kg/m2) underwent anthropometric and body composition assessments. ROI were defined as quadrilateral boxes extending 5 or 10 cm above the iliac crest and laterally to the edges of the abdominal soft tissue. A single‐slice computed tomography (CT) scan was measured at the L3 to L4 intervertebral space, and abdominal skinfolds were taken.

Results: Forward step‐wise regression revealed the best predictor model of IAAT area measured by CT (r2 = 0.68, standard error of estimate = 17%) to be: IAAT area (centimeters squared) = 51.844 + DXA 10‐cm ROI (grams) (0.031) + abdominal skinfold (millimeters) (1.342). Interobserver reliability for fat mass (r = 0.994; coefficient of variation, 2.60%) and lean mass (r = 0.986, coefficient of variation, 2.67%) in the DXA 10‐cm ROI was excellent.

Discussion: This study has identified a DXA ROI that can be reliably measured using prominent anatomical landmarks, in this case, the iliac crest. Using this ROI, combined with an abdominal skinfold measurement, we have derived an equation to predict IAAT in overweight/obese postmenopausal women. This approach offers a simpler, safer, and more cost‐effective method than CT for assessing the efficacy of lifestyle interventions aimed at reducing IAAT. However, this warrants further investigation and validation with an independent cohort.
Prediction of the resonant frequency of piezoelectric tube scanners through three-dimensional finite element modeling of a tube assembly
Authors: Zareian Jahromi S. Abdolali , Salomons Mark , Sun Qiao , Wolkow Robert A.
Published: July 2008

In this paper, we study the resonant behavior of a piezoelectric tube scanner used in scanning probe microscopes. In particular, we use a finite element model to allow the inclusion of boundary effects, i.e., nonrigid bonding layers and elastic tip holder, on the dynamic response of the scanner. We show that although existing analytical models provide a good estimation of the axial resonant frequency, their predictions of the first bending resonance may have up to a 100% error. In addition, a simple procedure is proposed that combines some precalculated factors to predict the lowest resonant frequency for a wide range of typical scanner dimensions. An experiment is carried out to illustrate the procedure and validate the prediction.
Limit to mass sensitivity of nanoresonators with random rough surfaces due to intrinsic sources and interactions with the surrounding gas
Authors: Palasantzas G.
Published: July 2008

We investigate initially the influence of thermomechanical and momentum exchange noise on the limit to mass sensitivity Δm of nanoresonators with random rough surfaces, which are characterized by the roughness amplitude w, the correlation length ξ, and the roughness exponent 0<H<1. In fact, Δm increases with increasing roughness (decreasing H and∕or increasing ratio w∕ξ) if the quality factor associated with thermomechanical noise is larger than that due to momentum exchange noise. Finally, the influence of adsorption-desorption noise, which is also influenced by the surface morphology, is shown to play a minimal role in the presence of the other two noise sources.
Ohmic contact for p-type diamond without postannealing
Authors: Teraji T. , Koizumi S. , Koide Y.
Published: July 2008

A new formation method of Ohmic contacts without postannealing was proposed for p-type boron-doped diamond. The diamond surface was partially covered with Au electrodes and then illuminated with vacuum ultraviolet light in an oxygen atmosphere. Through these processes, the hydrogen-terminated diamond surface was oxidized selectively, except for the areas beneath the Au electrodes. Consequently, the surface conductivity became negligibly small on the bare surface between the two electrodes, whereas as-deposited Au electrodes showed Ohmic properties for the lightly doped diamond with boron concentration of ∼1015 cm−3. The Ohmic properties were stable at temperatures up to 700 K.
Theory and simulations of electrostatic field error transport
Authors: Dubin Daniel H. E.
Published: July 2008

Asymmetries in applied electromagnetic fields cause plasma loss (or compression) in stellarators, tokamaks, and non-neutral plasmas. Here, this transport is studied using idealized simulations that follow guiding centers in given fields, neglecting collective effects on the plasma evolution, but including collisions at rate ν. For simplicity the magnetic field is assumed to be uniform; transport is due to asymmetries in applied electrostatic fields. Also, the Fokker–Planck equation describing the particle distribution is solved, and the predicted transport is found to agree with the simulations. Banana, plateau, and fluid regimes are identified and observed in the simulations. When separate trapped particle populations are created by application of an axisymmetric squeeze potential, enhanced transport regimes are observed, scaling as ν when ν<ω0<ωB and as 1∕ν when ω0<ν<ωB (where ω0 and ωB are the rotation and axial bounce frequencies, respectively). These regimes are similar to those predicted for neoclassical transport in stellarators.
Sensitivity of two-dimensional spatially developing mixing layers with respect to uncertain inflow conditions
Authors: Ko Jordan , Lucor Didier , Sagaut Pierre
Published: July 2008

The fidelity of numerical simulations of transport phenomena is often compromised by the difficulty in modeling the inherent experimental uncertainties. In this study, we examine the sensitivity of direct numerical simulations of two-dimensional spatially developing plane mixing layers to uncertainties in the inflow boundary conditions. In particular, we treat the magnitudes of discrete forcing modes (bimodal or trimodal) at the inflow as random variables. By applying a stochastic collocation method based on the generalized polynomial chaos, we determine the statistical moments and perform a sensitivity analysis of relevant time-averaged flow quantities with respect to the random inputs. In the bimodal perturbation case, we notice that the solutions are more sensitive to the changes in the subharmonic than the fundamental mode. We observe large spreads in the PDF contours of momentum and vorticity thicknesses and the most probable solution is distinctly different from the deterministic ones. In the trimodal perturbation case, the PDFs show large solution variations in momentum and vorticity thicknesses and the locations of the vortex interactions can be clearly related to the downstream evolutions of the most probable solutions. In both cases, the solution sensitivity to each perturbation mode is localized near the shear layer roll-up region associated with the respective modal frequency.
Impact ionization fronts in semiconductors: Superfast propagation due to nonlocalized preionization
Authors: Rodin Pavel , Minarsky Andrey , Grekhov Igor
Published: July 2008

We present a theoretical study of impact ionization fronts propagating into semiconductor with a constant electric field Em in presence of a small concentration of free nonequilibrium carriers—so-called preionization. We show that if this concentration decays in the direction of the front propagation with a small characteristic exponent λ, the front velocity is determined by vf≈2βm∕λ, where βm≡β(Em) is the corresponding ionization frequency. The propagation velocity vf can exceed the saturated drift velocity vs by several orders of magnitude even in moderate electric fields.
Composition-dependent damping and relaxation dynamics in miscible polymer blends above glass transition temperature by anelastic spectroscopy
Authors: Wu Xuebang , Shang Shuying , Xu Qiaoling , Liu Changsong , Zhu Zhengang , Zhang Guangzhao
Published: July 2008

Anelastic spectroscopy is used to study the composition dependence of the damping and molecular relaxation dynamics in miscible poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA) blends above the glass transition temperature. The ultrahigh damping peak of the relaxation type is shown to be associated with the liquid-liquid transition of PMMA. A higher PEO concentration leads to a higher damping performance and a lower transition temperature. The decreasing activation energy with increasing PEO concentration indicates a drastic increase in molecular mobility. Moreover, the relaxation time reveals a transition from the Vogel–Fulcher–Tamman behavior to the Arrhenius behavior due to the intermolecular guest-host interactions.
An efficient and accurate molecular alignment and docking technique using ab initio quality scoring
Authors: Füsti-Molnár László , Merz Kenneth M.
Published: July 2008

An accurate and efficient molecular alignment technique is presented based on first principle electronic structure calculations. This new scheme maximizes quantum similarity matrices in the relative orientation of the molecules and uses Fourier transform techniques for two purposes. First, building up the numerical representation of true ab initio electronic densities and their Coulomb potentials is accelerated by the previously described Fourier transform Coulomb method. Second, the Fourier convolution technique is applied for accelerating optimizations in the translational coordinates. In order to avoid any interpolation error, the necessary analytical formulas are derived for the transformation of the ab initio wavefunctions in rotational coordinates. The results of our first implementation for a small test set are analyzed in detail and compared with published results of the literature. A new way of refinement of existing shape based alignments is also proposed by using Fourier convolutions of ab initio or other approximate electron densities. This new alignment technique is generally applicable for overlap, Coulomb, kinetic energy, etc., quantum similarity measures and can be extended to a genuine docking solution with ab initio scoring.
Deformations and central extensions of the antibracket superalgebra
Authors: Konstein S. E. , Tyutin I. V.
Published: July 2008

We consider the antibracket superalgebras realized on the smooth Grassmann-valued functions with compact support in Rn and with the grading inverse to Grassmannian parity. The deformations and central extensions of these superalgebras are found. The results differ from the case of the antibracket superalgebras realized on the polynomial functions.
Electronic structure and thermoelectric properties of clathrate compounds Ba8AlxGe46−x
Authors: Uemura Takashi , Akai Koji , Koga Kenji , Tanaka Terumitsu , Kurisu Hiroki , Yamamoto Setsuo , Kishimoto Kengo , Koyanagi Tsuyoshi , Matsuura Mitsuru
Published: July 2008

Thermoelectric properties of Al-substituted Ge clathrate compounds Ba8AlxGe46−x were investigated experimentally and theoretically. Polycrystalline Ba8AlxGe46−x (x=12–18) was synthesized by using an arc melting and a spark plasma sintering technique. The obtained samples show the n-type behavior and the carrier concentration decreases with increasing amount of Al composition from x=12 to 16. The reasonably large power factors was obtained: 900–1000 μW/cm K2 around 900 K. Theoretically electronic structure of Ba8Al16Ge30 was calculated by means of a first-principles method and then thermoelectric properties were analyzed on the basis of the result of the calculated electronic structure. The calculated thermoelectric properties agree with the experimental results very well in the wide range of temperature between room temperature and 900 K.
Low-lying isomers of the B9− boron cluster: The planar molecular wheel versus three-dimensional structures
Authors: Pan Li-Li , Li Jun , Wang Lai-Sheng
Published: July 2008

The B9− cluster was found previously to be an unprecedented molecular wheel containing an octacoordinate planar boron with D8h symmetry in a combined photoelectron spectroscopy (PES) and theoretical study [H. J. Zhai et al., Angew. Chem., Int. Ed. 42, 6004 (2003)]. However, the PES spectra of B9− exhibit minor features that cannot be explained by the global minimum D8h structure, suggesting possible contributions from low-lying isomers at finite temperatures. Here we present Car–Parrinello molecular dynamics with simulated annealing simulations to fully explore the potential energy surface of B9− and search for low-lying isomers that may account for the minor PES features. We performed density functional theory (DFT) calculations with different exchange-correlation functionals and ab initio calculations at various levels of theory with different basis sets. Two three-dimensional low-lying isomers were found, both of Cs symmetry, 6.29 (Cs−2) and 10.23 (Cs−1)kcal∕mol higher in energy than the D8h structure at the highest CCSD(T) level of theory. Calculated detachment transitions from the Cs−2 isomer are in excellent agreement with the minor features observed in the PES spectra of B9−. The B9− cluster proves to be a challenge for most DFT methods and the calculated relative energies strongly depend on the exchange-correlation functionals, providing an excellent example for evaluating the accuracies of various DFT methods.
Diode-pumped laser operation of Yb3+-doped Y2Ca3B4O12 crystal
Authors: Brenier Alain , Tu Chaoyang , Wang Yan , You Zhenyu , Zhu Zhaojie , Li Jianfu
Published: July 2008

We report in the present paper the Yb3+-doped Y2Ca3B4O12 diode-pumped laser operation in both continuous-wave (cw) and passively Q-switched modes. The differential slopes of the cw output power are in the 22%–40% range under different experimental conditions. Continuous tuning of the laser wavelength is obtained in the 1020–1057 nm range, in agreement with the broad emission spectra. In pulsed regime the repetition rate occurs up to 1.6 kHz and pulse energies of 30–75 μJ with about 40 ns duration are obtained.
An analytical model to determine equilibrium quantities of azimuthally symmetric and mismatched charged particle beams under linear focusing
Authors: Nunes R. P. , Pakter R. , Rizzato F. B.
Published: July 2008

The model developed here analytically allows to obtain equilibrium quantities of interest from high-intensity charged particle beams such as the emittance, beam envelope, and the number of beam halo particles. The results obtained in this work have been particularized to the case of initially homogeneous beams, with azimuthal symmetry, and focused by a constant magnetic field while confined in a linear channel. For validation, full self-consistent N-particle beam simulations have been carried out and its results compared with the predictions supplied by the developed hybrid numerical-analytical model. The agreement has been reasonable. Also, the model revealed to be useful to understand the basic physical aspects of the problem.
Sound wave propagation in single-walled carbon nanotubes with initial axial stress
Authors: Heireche H. , Tounsi A. , Benzair A. , Mechab I.
Published: July 2008

This paper studies the vibrational characteristics of single-walled carbon nanotubes (SWNTs) with initial axial loading based on the theory of nonlocal elasticity. The consistent equations of motion for the nonlocal Euler-Bernoulli and Timoshenko beam models are provided taking into account the initial axial stress. The small scale effect on CNT wave propagation dispersion relation is explicitly revealed for different CNT wave numbers and diameters by theoretical analyses and numerical simulations. In addition, the applicability of the two beam models is explored by numerical simulations. The research work reveals the significance of the effects of small scale, transverse shear deformation and rotary inertia on wave propagation in short SWCNTs with initial axial loading.
Wake formation behind a rolling sphere
Authors: Stewart B. E. , Leweke T. , Hourigan K. , Thompson M. C.
Published: July 2008

Experimental flow visualizations are presented depicting the flow behind a spherical body moving on a plane wall. In the Reynolds number range of 100<Re<350, four distinct wake modes occur which are dependent on the imposed rotation rate of the body. Five different rotation rates are examined: two with forward rolling, one with pure translation (zero rotation), and two with reversed rolling. As the sphere undergoes forward rolling, steady and unsteady wake modes are observed which bear similarities to the flow behind an isolated sphere in a free stream. However, for cases with reversed and zero rotation of the sphere, a new antisymmetric wake mode is discovered.