bluuebunny/crossref_metadata_2025 huggingface dataset:
Equilibria in the system Au–Ag–S–fluid: computed and experimental data
Authors: Laptev Yu.V.
Published: April 2008

We present results of computations on the interaction of solid-phase electrum–argentite–pyrite (weight ratios 2⋅10−5/2⋅10−3/1 and 2⋅10−5/4⋅10−2/1) association with Cl-containing aqueous moderately acid solutions (0.5m NaCl, pH = 3.08) at 300 °C and 500 bars. These data are a physicochemical basis for predicting the geochemical behavior of Au and Ag during the hydrothermal-metasomatic transformation of Au-Ag-pyrite. We also propose a technique of study of this process based on the phase equilibria of the subsystem Au–Ag–S with the aqueous solution at different liquid/solid (l/s) ratios, with the use of new graphic diagrams. The relationship of the composition of the solid-phase association with l/s ratio in real boundary conditions (Au = 17 ppm, mAu/mAg = 10–3.57–10–2.28) is shown. The maximum l/s values for complete leaching of gold and silver (l/smax = 200–800) are estimated. It has been established that argentite is the first to dissolve when mAu/mAg(s) > mAu/mAg(sol), and electrum, when mAu/mAg(s) < mAu/mAg(sol).

The experimental results showed that at 300 °C, the conversion of electrum (NAu = 300‰) nonequilibrated with pyrite into an Au-richer form (NAu = 730‰) and argentite follows an intricate kinetic scheme. Using the Pilling-Bedwords kinetic equation for processing data yielded the process rate constant K = 2.8(±0.5)⋅10−5 g2⋅cm−4⋅day−1. With this equation, the time of the complete conversion of 200 μm thick flat gold grains is 604 days. These data evidence a significant role of kinetic factors in hydrothermal-metasomatic processes involving native gold, which requires combination of thermodynamic and kinetic approaches on the construction of geologo-genetic models for hydrothermal sulfide formation.
Simulating the heating of z-pinch plasmas with short laser pulses
Authors: WIENEKE S. , BRÜCKNER S. , VIÖL W.
Published: April 2008

The longitudinal heating of a z-pinch plasma with short laser pulses is simulated using COMSOL Multiphysics. The heating of an existing pinch plasma for different electron densities with a short laser pulse is shown. It is illustrated that the initial electron density of the plasma has a significant impact on penetration of the pulse and subsequent heating of the plasma. With a Nd:YAG laser pulse the most effective heating occurs when the initial electron density is about 1/15 of the critical electron density of the plasma. It is shown that by increasing the initial electron density by even a factor of two above this level causes the absorption to increase dramatically, preventing penetration of the laser pulse and greatly limiting the heating of the plasma.
Pacific Ocean and Cenozoic evolution of climate
Authors: Lyle Mitchell , Barron John , Bralower Timothy J. , Huber Matthew , Olivarez Lyle Annette , Ravelo A. Christina , Rea David K. , Wilson Paul A.
Published: April 2008

The Pacific Ocean has played a major role in climate evolution throughout the Cenozoic (65–0 Ma). It is a fundamental component of global heat transport and circulation, the dominant locus of primary productivity, and, consequently, the largest reservoir for carbon exchange between the oceans and the atmosphere. A satisfactory understanding of the Cenozoic evolutionary history of the Pacific and its impact on global climate is currently data‐limited. Nevertheless, the large dynamic range of Cenozoic conditions sets the stage to greatly expand our understanding of global climate and biogeochemical cycles. Past Earth “experiments” are particularly useful to understand interactions between climate and geosystems under different greenhouse gas loads. We highlight in this review four important problems in which the Pacific played a major role: the effect of changing geographic boundary conditions on ocean circulation; interactions between the carbon cycle and climate; the Pacific Ocean's influence on North American climate and its water cycle; and the gradual evolution of climate systems.
San Andreas Fault damage at SAFOD viewed with fault‐guided waves
Authors: Li Yong‐Gang , Malin Peter E.
Published: April 2008

Highly damaged rocks within the San Andreas fault zone at Parkfield form a low‐velocity waveguide for seismic waves, giving rise to fault‐guided waves. Prominent fault‐guided waves have been observed at the San Andreas Fault Observatory at Depth (SAFOD) site, including a surface array across the fault zone and a borehole seismograph placed in the SAFOD well at a depth of ∼2.7 km below ground. The resulting observations are modeled here using 3‐D finite‐difference methods. To fit the amplitude, frequency, and travel‐time characteristics of the data, the models require a downward tapering, 30–40‐m wide fault‐core embedded in a 100–200‐m wide jacket. Compared with the intact wall rocks, the core velocities are reduced by ∼40% and jacket velocities by ∼25%. Based on the depths of earthquakes generating guided waves, we estimate that the low‐velocity waveguide along the fault at SAFOD extends at least to depths of ∼7 km, more than twice the depth reported in pervious studies.
How does a weakened Atlantic thermohaline circulation lead to an intensification of the ENSO‐south Asian summer monsoon interaction?
Authors: Lu Riyu , Chen Wei , Dong Buwen
Published: April 2008

This study investigates the change of the El Niño–Southern Oscillation (ENSO)‐South Asian summer monsoon interaction in response to a weakened Atlantic thermohaline circulation (THC) by applying an additional freshwater flux into the North Atlantic. The simulated results indicate that the weakened THC leads to intensified ENSO‐South Asian summer monsoon relationship and enhanced South Asian summer monsoon interannual variability. Furthermore, it is suggested that this intensification of the ENSO‐monsoon relationship is likely due to the enhanced ENSO variability induced by the weakened THC. This study indicates that the low frequency fluctuation of Atlantic SSTs might have an influence on South Asian summer monsoon interannual variability and the ENSO‐monsoon interaction, and suggests a nonlocal mechanism for the observed decadal‐multidecadal modulation of ENSO‐monsoon relationship.
Another look at the 1960 Perth to Bermuda long‐range acoustic propagation experiment
Authors: Dushaw Brian D.
Published: April 2008

During a 1960 experiment on long‐range ocean acoustic propagation, the signals of explosive shots made near Perth, Australia were recorded by a hydrophone array at Bermuda. The acoustic paths followed by those pulses are recalculated using a modern atlas for global ocean sound speed. The blocking or refractive effects of topographic features, besides continents, are ignored in this simple calculation. No direct path to the hydrophone array is obtained, and the array is found to be in the acoustic shadow by 300–400 km. The large energy of the 300‐lb explosive sound sources required for adequate SNR at the receiver also points to a shadowed reception. Given nominal estimates for temperature warming on the sound channel axis due to climate change, the experiment repeated today would give signals that arrive 12 s earlier, but this signal could not be reliably measured because of intra‐annual variability.
High Expression of Complement Components in Omental Adipose Tissue in Obese Men
Authors: Gabrielsson Britt G. , Johansson Jenny M. , Lönn Malin , Jernås Margareta , Olbers Torsten , Peltonen Markku , Larsson Ingrid , Lönn Lars , Sjöström Lars , Carlsson Björn , Carlsson Lena M.S.
Published: April 2008

Objective: Accumulation of visceral fat is recognized as a predictor of obesity‐related metabolic disturbances. Factors that are predominantly expressed in this depot could mediate the link between visceral obesity and associated diseases.

Research Methods and Procedures: Paired subcutaneous and omental adipose tissue biopsies were obtained from 10 obese men. Gene expression was analyzed by DNA microarrays in triplicate and by real‐time polymerase chain reaction. Serum C3 and C4 were analyzed by radial immunodiffusion assays in 91 subjects representing a cross section of the general population. Body composition was measured by computerized tomography.

Results: Complement components C2, C3, C4, C7, and Factor B had higher expression in omental compared with subcutaneous adipose tissue (∼2‐, 4‐, 17‐, 10‐, and 7‐fold, respectively). In addition, adipsin, which belongs to the alternative pathway, and the classical pathway components C1QB, C1R, and C1S were expressed in both depots. Analysis of tissue distribution showed high expression of C2, C3, and C4 in omental adipose tissue, and only liver had higher expression of these genes. Serum C3 levels correlated with both visceral and subcutaneous adipose tissue in both men (r = 0.65 and p < 0.001 and r = 0.52 and p < 0.001, respectively) and women (r = 0.34 and p = 0.023 and r = 0.49 and p < 0.001, respectively), whereas C4 levels correlated with only visceral fat in men (r = 0.36, p = 0.015) and with both depots in women (visceral: r = 0.58, p < 0.001; and subcutaneous: r = 0.51, p < 0.001).

Discussion: Recent studies show that the metabolic syndrome is associated with chronically elevated levels of several immune markers, some of which may have metabolic effects. The high expression of complement genes in intra‐abdominal adipose tissue might suggest that the complement system is involved in the development of visceral adiposity and/or contributes to the metabolic complications associated with increased visceral fat mass.
Medium‐Chain Oil Reduces Fat Mass and Down‐regulates Expression of Adipogenic Genes in Rats
Authors: Han Jianrong , Hamilton James A. , Kirkland James L. , Corkey Barbara E. , Guo Wen
Published: April 2008

Objective: To test the hypothesis that adipose tissue could be one of the primary targets through which medium‐chain fatty acids (MCFAs) exert their metabolic influence.

Research Methods and Procedures: Sprague‐Dawley rats were fed a control high‐fat diet compared with an isocaloric diet rich in medium‐chain triglycerides (MCTs). We determined the effects of MCTs on body fat mass, plasma leptin and lipid levels, acyl chain composition of adipose triglycerides and phospholipids, adipose tissue lipoprotein lipase activity, and the expression of key adipogenic genes. Tissue triglyceride content was measured in heart and gastrocnemius muscle, and whole body insulin sensitivity and glucose tolerance were also measured. The effects of MCFAs on lipoprotein lipase activity and adipogenic gene expression were also assessed in vitro using cultured adipose tissue explants or 3T3‐L1 adipocytes.

Results: MCT‐fed animals had smaller fat pads, and they contained a considerable amount of MCFAs in both triglycerides and phospholipids. A number of key adipogenic genes were down‐regulated, including peroxisome proliferator activated receptor γ and CCAAT/enhancer binding protein α and their downstream metabolic target genes. We also found reduced adipose tissue lipoprotein lipase activity and improved insulin sensitivity and glucose tolerance in MCT‐fed animals. Analogous effects of MCFAs on adipogenic genes were found in cultured rat adipose tissue explants and 3T3‐L1 adipocytes.

Discussion: These results suggest that direct inhibitory effects of MCFAs on adiposity may play an important role in the regulation of body fat development.
Obesity in 70‐Year‐Old Subjects as a Risk Factor for 15‐Year Coronary Heart Disease Incidence
Authors: Dey Debashish K. , Lissner Lauren
Published: April 2008

Objective: To investigate the role of obesity in general and waist circumference (WC) and BMI in particular as risk factors for 15‐year incidence of coronary heart disease (CHD) in the elderly.

Research Methods and Procedures: This prospective study was based on 1597 (737 males and 860 females) 70‐year‐olds free from CHD and participants of three birth cohorts examined in 1971 to 1972 (Cohort I), 1976 to 1977 (Cohort II), and 1981 to 1982 (Cohort III) at Göteborg, Sweden. Fifteen‐year incidence of CHD (fatal and nonfatal) was ascertained from follow‐up examinations and registers. Relative risk (RR) for first ever CHD in reference to the lowest quartiles of WC and BMI was calculated from Cox regression.

Results: In males, RRs for CHD in the highest WC and BMI quartiles were 1.36 [95% confidence interval (CI) 1.00 to 1.85] and 1.42 (95% CI 1.04 to 1.92), respectively, after adjustment for cohorts, smoking habits, diabetes, systolic blood pressure, and total cholesterol. In men, the risk associated with WC was independent of BMI. Neither WC nor BMI was related to CHD risk in females. After exclusion of first 5‐year all‐cause deaths, the adjusted RRs in the highest WC and BMI quartiles in males were 1.47 (95% CI 1.06 to 2.04) and 1.42 (1.04 to 1.92), respectively. In females, a significantly higher RR of 1.41 (95% CI 1.02 to 1.94) was observed in the second BMI quartile only after such exclusions.

Discussion: WC, an indicator of both central and general obesity, appears to be a stronger predictor of CHD than BMI in elderly males, but in females, obesity was not a risk factor for CHD.
Meal Pattern Analysis of Diet‐Induced Obesity in Susceptible and Resistant Rats
Authors: Farley Constance , Cook John A. , Spar Brian D. , Austin Theodore M. , Kowalski Timothy J.
Published: April 2008

Objective: To characterize the meal patterns of free feeding Sprague‐Dawley rats that become obese or resist obesity when chronically fed a high‐fat diet.

Research Methods and Procedures: Male Sprague‐Dawley rats (N = 120) were weaned onto a high‐fat diet, and body weight was monitored for 19 weeks. Rats from the upper [diet‐induced obese (DIO)] and lower [diet‐resistant (DR)] deciles for body‐weight gain were selected for study. A cohort of chow‐fed (CF) rats weight‐matched to the DR group was also studied. Food intake was continuously monitored for 7 consecutive days using a BioDAQ food intake monitoring system.

Results: DIO rats were obese, hyperphagic, hyperleptinemic, hyperinsulinemic, hyperglycemic, and hypertriglyceridemic relative to the DR and CF rats. The hyperphagia of DIOs was caused by an increase in meal size, not number. CF rats ate more calories than DR rats; however, this was because of an increase in meal number, not size. When expressed as a function of lean mass, CF and DR rats consumed the same amount of calories. The intermeal intervals of DIO and DR rats were similar; both were longer than CF rats. The nocturnal satiety ratio of DIO rats was significantly lower than DR and CF rats. The proportion of calories eaten during the nocturnal period did not differ among groups.

Discussion: The hyperphagia of a Sprague‐Dawley rat model of chronic diet‐induced obesity is caused by an increase in meal size, not number. These results are an important step toward understanding the mechanisms underlying differences in feeding behavior of DIO and DR rats.
Weekend Eating in the United States Is Linked with Greater Energy, Fat, and Alcohol Intake
Authors: Haines Pamela S. , Hama Mary Y. , Guilkey David K. , Popkin Barry M.
Published: April 2008

Objectives: To determine if macronutrient consumption for the U.S. population is greater on weekend days than weekdays.

Research Methods and Procedures: The nationally representative 1994 to 1996 Continuing Survey of Food Intakes by Individuals was used for this analysis. Dietary intake was assessed using two independent days of dietary recall data. Ordinary least squares multivariate analysis was used to analyze dietary outcome variables to explore the effect of weekend day vs. weekday intake.

Results: This study's results indicate that statistically significant dietary intake differences occur for different days of the week but not for all age groups—nor for all nutrients. The average American, 2 years and older, consumes 82 kcal more per day on each weekend day (Friday through Sunday) than they do on weekdays (Monday through Thursday). These overall increases in dietary intake are significant for the overall sample and are largest for the 19‐ to 50‐year‐old age group; among this age group, the weekend day increase (vs. weekday) is 115 kcal/d. The increased proportions of energy from fat and alcohol consumed on weekends are greater for this adult age group by 0.7% and 1.4%, respectively, whereas the proportion of energy from carbohydrate decreases 1.6%.

Discussion: The effects of weekend days on nutrient intake are substantial and should be considered in future clinical and population‐based interventions and in dietary monitoring and research in the U.S.
Patterns of Overweight, Inactivity, and Snacking in Chinese Children
Authors: Waller Carrie E. , Du Shufa , Popkin Barry M.
Published: April 2008

Objective: To examine patterns of inactivity and snacking and their relationship with overweight status in Chinese children.

Research Methods and Procedures: The study population was drawn from the 1997 China Health National Survey (1385 children, ages 6 to 11 years), conducted with a representative sample from nine provinces. The 2000 Centers for Disease Control and Prevention BMI charts were used to calculate “at risk of overweight” as those above the 85th percentile. Three days of 24‐hour recall dietary data and detailed questions on physical activity and inactivity for the previous 7 days were used.

Results: 9.4% of the children were classified as overweight. Weekly mean and range of hours spent watching television/videos, playing video games, studying, and in inactive transport were 5.1 (0 to 35), 0.3 (0 to 10), 4.7 (0 to 60), and 0.14 (0 to 4.2), respectively. Television/video viewing and studying did not differ in any meaningful manner between overweight and normal weight children. Snacking is inconsequential in China, comprising only 0.9% of energy intake.

Discussion: Chinese children are less overweight, less inactive, and less likely to ingest calories as snacks than children in the U.S. The absence of impact of these measures of inactivity, which are below an hour per day for the average Chinese child, indicate the possible value of limiting television viewing and other types of inactivity in other countries. Modern Western‐style television programming and advertising started to come to China after 1997; therefore, extensive changes in television viewing patterns are expected to emerge.
Trends of Abdominal Adiposity in White, Black, and Mexican‐American Adults, 1988 to 2000
Authors: Okosun Ike S. , Choi Simon T. , Boltri John M. , Parish David C. , Chandra K.M. Dinesh , Dever G.E. Alan , Lucas Amy
Published: April 2008

Objective: To describe changes in the distribution of waist circumference (WC) and abdominal obesity (AO) in white, black, and Mexican‐American adults from 1988 through 2000.

Research Methods and Procedures: Nationally representative cross‐sectional surveys of adults 20 to 79 years of age were examined using data from U.S. National Health and Nutrition Examination Surveys of 1988 to 1994 and 1999 to 2000. AO was defined as WC ≥102 cm in men and ≥88 cm in women.

Results: There was a gradient of increasing WC and AO with increasing age in both study periods in whites and blacks. In men, the average increase between the study periods in overall WC in whites, blacks, and Mexican Americans were 3, 3.3, and 3.4 cm, respectively. The corresponding values in women were 2.4, 5.3, and 3.7 cm, respectively. In men, the percentage change in prevalence of AO between 1988 and 2000 ranged from 5.5% in Mexican‐American men to 8.2% in white men. In women, there was a 1.7% decrease in AO in Mexican Americans, whereas there was an increase of 6.3% for whites and 7% for blacks.

Discussion: Despite increased understanding of the need for screening and treatment for obesity, this study indicates increasing prevalence of AO in white and black Americans. Without concerted effort to reduce the prevalence of overall obesity, the increasing prevalence of AO is likely to lead to increased prevalence of metabolic syndromes in the United States. Our results highlight the need to design evidence‐based programs that show promise for long‐term health behavior changes to facilitate the prevention of AO and related comorbidities.
Impact of Objective and Subjective Social Status on Obesity in a Biracial Cohort of Adolescents
Authors: Goodman Elizabeth , Adler Nancy E. , Daniels Stephen R. , Morrison John A. , Slap Gail B. , Dolan Lawrence M.
Published: April 2008

Objective: To characterize the associations between socioeconomic status (SES), two levels of subjective social status (SSS), and adolescent obesity.

Research Methods and Procedures: Cross‐sectional study of 1491 black and white adolescents attending public school in a suburban school district in Greater Cincinnati, Ohio. BMI ≥95th percentile derived from measured height and weight defined overweight. Students rated SSS on separate 10‐point scales for society and school. A parent provided information on parent education and household income for SES.

Results: Although there were no sex differences in SES, black students were more likely to come from families with less well‐educated parents and lower incomes (p < 0.001). Black girls had the lowest societal SSS (p = 0.003), lowest school SSS (p = 0.046), and highest BMI (p < 0.001). Prevalence of overweight was highest among black girls (26.0%) and boys (26.2%), intermediate for white boys (17.2%), and least for white girls (11.6%). Logistic regression modeling revealed that parent education, household income, and school SSS were each associated with overweight. In a fully adjusted model, school SSS retained its association to overweight (odds ratio, 1.16; 95% CI, 1.06, 1.26) independent of SES. The association of school SSS was strongest among white girls, intermediate for white and black boys, and absent for black girls.

Discussion: Perceptions of social stratification are independently associated with overweight. There were important racial and sex differences in the social status‐overweight association. SSS in the more immediate, local reference group, the school, had the strongest association to overweight.
Relationship among Habitual Tea Consumption, Percent Body Fat, and Body Fat Distribution
Authors: Wu Chih‐Hsing , Lu Feng‐Hwa , Chang Chin‐Song , Chang Tsui‐Chen , Wang Ru‐Hsueh , Chang Chih‐Jen
Published: April 2008

Objective: To disclose the possible relationship between habitual tea consumption and changes in total body fat and fat distribution in humans.

Research Methods and Procedures: A cross‐sectional survey of 1210 epidemiologically sampled adults (569 men and 641 women) were enrolled in our study. Tea consumption and other lifestyle characteristics were obtained by structured questionnaires. Percent body fat (BF%) was measured using bioelectrical impedance analysis. Body fat distribution was assessed using waist‐to‐hip ratio (WHR).

Results: Among the 1103 analyzed subjects, 473 adults (42.9%) consumed tea once or more per week for at least 6 months. The habitual tea drinkers were male‐dominant, more frequently current smokers, and alcohol or coffee drinkers than the nonhabitual tea drinkers. Habitual tea drinkers for more than 10 years showed a 19.6% reduction in BF% and a 2.1% reduction in WHR compared with nonhabitual tea drinkers. The multiple stepwise regression models revealed that men, older age, higher BMI, and current smokers were positive factors for BF% and WHR. In contrast, longer duration of habitual tea consumption and higher total physical activity were negative factors for BF%. Longer duration of habitual tea consumption, higher socioeconomic status, and premenopausal status were negative factors for WHR.

Discussion: An inverse relationship may exist among habitual tea consumption, BF%, and body fat distribution, especially for subjects who have maintained the habit of tea consumption for more than 10 years.
Conjugated Linoleic Acid Does Not Improve Insulin Tolerance in Mice*
Authors: Hargrave Kimberly M. , Azain Michael J. , Kachman Stephen D. , Miner Jess L.
Published: April 2008

Objective: To determine if the addition or removal of dietary conjugated linoleic acid (CLA) would alter insulin tolerances in mice from two genetic lines.

Research Methods and Procedures: High metabolic rate (MH) and low metabolic rate (ML) mice were assigned to consume 1) a control diet ad libitum, 2) a control diet at a restricted intake, or 3) a diet containing 1% CLA ad libitum. After 9 weeks, an insulin tolerance test was conducted, and a portion of the mice were killed. All remaining mice consumed the control diet ad libitum. Insulin tolerance tests were conducted 11 and 32 days after the diet change, and mice were killed 3 days after each test. Body fatness, fat pad weights, and serum insulin concentrations of mice were determined at each time‐point. Two follow‐up experiments were also conducted.

Results: Restricted mice had insulin sensitivities not different than control mice. CLA‐fed MH mice in experiment 1 were resistant (p < 0.001) to insulin on each day measured. CLA‐fed ML mice were slightly resistant (p = 0.08) to exogenous insulin on day 0 of recovery and not different from control mice on day 11 or 32. Glucose response to insulin in MH mice fed CLA in experiments 2 or 3 did not differ from control mice.

Discussion: Mice fed CLA did not have improved insulin tolerances compared with control mice. In some cases, dietary CLA may cause insulin resistance. MH mice seem more sensitive to CLA than ML mice.
Effect of Sibutramine on Weight Loss and Blood Pressure: A Meta‐analysis of Controlled Trials
Authors: Kim Su Hyun , Lee Young Mee , Jee Sun Ha , Nam Chung Mo
Published: April 2008

Objective: Sibutramine causes weight loss by suppressing the appetite and by promoting energy expenditure, but it can also increase blood pressure through a norepinephrine effect. The aim of this study was to provide a comprehensive meta‐analysis of randomized, controlled trials on the effects of sibutramine on blood pressure and weight loss.

Research Methods and Procedures: Twenty‐one placebo‐controlled, double‐blind, randomized trials of sibutramine were identified using MEDLINE, EMBASE, and a manual search. The effect sizes of sibutramine on weight and systolic (SBP) and diastolic (DBP) blood pressure changes were estimated. Subgroup analyses were undertaken to explore the relationship between effect sizes and the study characteristics.

Results: The effect size of sibutramine on weight change was −1.00 (−1.17 to −0.84), whereas the effect sizes on SBP and DBP changes were 0.16 (0.08 to 0.24) and 0.26 (0.18 to 0.33), respectively. By subgroup analysis, the effect sizes on weight loss were significantly larger when the dosage was ≥15 mg. The effect sizes on increased SBP were significantly larger when the initial body weight was ≥92 kg and the age was <44 years; similarly, the effect sizes on increased DBP were significantly larger when the initial weight was ≥92 kg.

Discussion: Sibutramine showed a large effect on weight loss. Because blood pressure was found to be increased slightly, but significantly, sibutramine should be used cautiously in patients with borderline or high blood pressure. Additional studies on its effect on blood pressure are needed.
What's in a Name? Patients’ Preferred Terms for Describing Obesity
Authors: Wadden Thomas A. , Didie Elizabeth
Published: April 2008

Objective: To determine the terms that obese individuals find undesirable or desirable for their doctors to use to describe excess weight of 27.3 kg (i.e., 50 lb) or more.

Research Methods and Procedures: The study surveyed 167 women and 52 men with a mean BMI of 35.3 and 35.1 kg/m2, respectively, who participated in one of two randomized trials on the treatment of obesity. An additional sample consisted of 105 extremely obese women (i.e., mean BMI of 52.5 kg/m2) who sought bariatric surgery. Patients rated the desirability of 11 terms used to describe excess weight. Ratings were made on five‐point scales, ranging from very desirable (+2) to neutral (0) to very undesirable (−2).

Results: Obese women (N = 167) rated as undesirable to very undesirable the terms fatness (mean rating = −1.8), excess fat (−1.4), obesity (−1.4), and large size (−1.3). These four terms were rated as significantly more (all p ≤ 0.001) undesirable than the seven remaining descriptors, which included weight, heaviness, BMI, excess weight, unhealthy body weight, weight problem, and unhealthy BMI. The term weight received a mean rating of 1.1, a value significantly more (all p ≤ 0.001) desirable than that for all other descriptors. Highly similar ratings of the terms were provided by obese men (N = 52) and extremely obese women (N = 105).

Discussion: Practitioners may wish to avoid the use of potentially derogatory terms such as fatness and obesity when broaching the topic of weight management with patients.
An Objective Method for Measurement of Sedentary Behavior in 3‐ to 4‐Year Olds
Authors: Reilly John J. , Coyle Jennifer , Kelly Louise , Burke Genevieve , Grant Stanley , Paton James Y.
Published: April 2008

Objective: To test the ability of accelerometry to quantify sedentary behavior in 3‐ to 4‐year‐old children.

Research Methods and Procedures: We developed a cut‐off for accelerometry output (validation study) in 30 healthy 3 to 4 year olds, which provided highest sensitivity and specificity for the detection of sedentary behavior relative to a criterion method of measurement, direct observation using the children's physical activity form. We then cross‐validated the cut‐off in an independent sample of healthy 3 to 4 year olds (n = 52).

Results: In the validation study, optimal sensitivity and specificity for the detection of sedentary behavior were obtained at an accelerometry output cut‐off of <1100 counts/min. In the cross‐validation, sensitivity was 83%: 438/528 inactive minutes were correctly classified. Specificity was 82%: 1251/1526 noninactive minutes were correctly classified using this cut‐off.

Discussion: Sedentary behavior can be quantified objectively in young children using accelerometry. This new technique could be considered for a wide variety of applications in the etiology, prevention, and treatment of childhood obesity.
Labor Saved, Calories Lost: The Energetic Impact of Domestic Labor‐saving Devices
Authors: Lanningham‐Foster Lorraine , Nysse Lana J. , Levine James A.
Published: April 2008

Objective: As the prevalence of obesity has increased, so has sedentariness. Progressive sedentariness has been attributed to greater use of labor saving devices, such as washing machines, and less nonexercise walking (e.g., walking to work). However, there is a paucity of data to support this conclusion. In this study, we address the hypothesis that domestic mechanization of daily tasks has resulted in less energy expenditure compared with performing the same tasks manually.

Research Methods and Procedures: Energy expenditure was measured in four groups of subjects (122 healthy adult men and women total) from Rochester, Minnesota. Energy expenditure was measured using indirect calorimetry while subjects performed structured tasks such as cleaning dishes and clothes, stair climbing, and work‐associated transportation, and these values were compared with the respective mechanized activity.

Results: Energy expenditure was significantly greater and numerically substantial when daily domestic tasks were performed without the aid of machines or equipment (clothes washing: 45 ± 14 vs. 27 ± 9 kcal/d; dish washing: 80 ± 28 vs. 54 ± 19 kcal/d; transportation to work: 83 ± 17 vs. 25 ± 3 kcal/d; stair climbing: 11 ± 7 vs. 3 ± 1 kcal/d; p < 0.05). The combined impact of domestic mechanization was substantial and equaled 111 kcal/d.

Discussion: The magnitude of the energetic impact of the mechanized tasks we studied was sufficiently great to contribute to the positive energy balance associated with weight gain. Efforts focused on reversing sedentariness have the potential to impact obesity.
Impact of Weight Loss and Regain on Quality of Life: Mirror Image or Differential Effect?
Authors: Engel Scott G. , Crosby Ross D. , Kolotkin Ronette L. , Hartley Guilford G. , Williams G. Rhys , Wonderlich Stephen A. , Mitchell James E.
Published: April 2008

Objective: To compare the impact of weight regain and weight loss on health‐related quality of life.

Research Methods and Procedures: Subjects were 122 (106 women, 16 men) overweight and obese participants in a weight reduction program (phentermine‐fenfluramine and dietary counseling) who had initially lost at least 5% of their total body weight and then regained at least 5% of their weight during the follow‐up period. Follow‐up periods ranged from 10 to 41 months (mean, 28 months). Participants completed the Impact of Weight on Quality of Life‐Lite, an obesity‐specific health‐related quality of life (HRQOL) measure, at 3‐month intervals.

Results: Mean BMI at baseline was 40.9 ± 6.6 kg/m2 (range, 29.2 to 63.7 kg/m2). Average weight loss from entry was 18.8 ± 6.7% (range, 6.0% to 43.7%), and average regain was 10.1 ±4.4% of baseline weight (range, 5.0% to 30.6%). The effects of weight regain on HRQOL mirrored the effects of weight loss—rates of HRQOL change were similar in magnitude but different in direction for comparable weight loss and regain. Those with more severe initial impairments in HRQOL experienced greater improvements in HRQOL during weight loss as well as greater deterioration during weight regain than those with less severe impairments.

Discussion: Weight loss and regain produced mirror image changes in HRQOL. The initial severity of HRQOL impairment had a greater impact on the magnitude of HRQOL change than the direction of weight change. Findings underscore the importance of maintaining weight loss for the purposes of retaining obesity‐specific HRQOL benefits.
Endothelial Dysfunction in Obesity and Insulin Resistance: A Road to Diabetes and Heart Disease
Authors: Caballero A. Enrique
Published: April 2008

Obesity, insulin resistance, and endothelial dysfunction closely coexist throughout the natural history of type 2 diabetes. They all can be identified not only in people with type 2 diabetes, but also in various groups at risk for the disease, such as individuals with impaired glucose tolerance, family history of type 2 diabetes, hypertension, dyslipidemia, prior gestational diabetes, or polycystic ovary syndrome. Whereas their evident association cannot fully establish a cause‐effect relationship, fascinating mechanisms that bring them closer together than ever before are rapidly emerging. Central or abdominal obesity leads to insulin resistance and endothelial dysfunction through fat‐derived metabolic products, hormones, and cytokines. Insulin resistance leads to endothelial dysfunction through the frequent association with traditional cardiovascular risk factors and through some more direct novel mechanisms. Some specific and shared insulin signaling abnormalities in muscle, fat, and endothelial cells, as well as some new genetic and nontraditional factors, may contribute to this interesting association. Some recent clinical studies demonstrate that nonpharmacological and pharmacological strategies targeting obesity and/or insulin resistance ameliorate endothelial function and low‐grade inflammation. All these findings have added a new dimension to the association of obesity, insulin resistance, and endothelial dysfunction that may become a key target in the prevention of type 2 diabetes and cardiovascular disease.
Economic Analysis of a School‐Based Obesity Prevention Program
Authors: Wang Li Yan , Yang Quanhe , Lowry Richard , Wechsler Howell
Published: April 2008

Objective: To assess the cost‐effectiveness and cost‐benefit of Planet Health, a school‐based intervention designed to reduce obesity in youth of middle‐school age children.

Research Methods and Procedures: Standard cost‐effectiveness analysis methods and a societal perspective were used in this study. Three categories of costs were measured: intervention costs, medical care costs associated with adulthood overweight, and costs of productivity loss associated with adulthood overweight. Health outcome was measured as cases of adulthood overweight prevented and quality‐adjusted life years (QALYs) saved. Cost‐effectiveness ratio was measured as the ratio of net intervention costs to the total number of QALYs saved, and net‐benefit was measured as costs averted by the intervention minus program costs.

Results: Under base‐case assumptions, at an intervention cost of $33, 677 or $14 per student per year, the program would prevent an estimated 1.9% of the female students (5.8 of 310) from becoming overweight adults. As a result, an estimated 4.1 QALYs would be saved by the program, and society could expect to save an estimated $15, 887 in medical care costs and $25, 104 in loss of productivity costs. These findings translated to a cost of $4305 per QALY saved and a net saving of $7313 to society. Results remained cost‐effective under all scenarios considered and remained cost‐saving under most scenarios.

Discussion: The Planet Health program is cost‐effective and cost‐saving as implemented. School‐based prevention programs of this type are likely to be cost‐effective uses of public funds and warrant careful consideration by policy makers and program planners.
Inflammation Markers Predict Increased Weight Gain in Smoking Quitters
Authors: Duncan Bruce B. , Schmidt Maria Inês , Chambless Lloyd E. , Folsom Aaron R. , Heiss Gerardo ,   Atherosclerosis Risk in Communities Study Investigators
Published: April 2008

Objective: Undesirable weight gain often follows smoking cessation. We investigated whether weight gain after smoking cessation is greater in those with higher levels of inflammatory markers.

Research Methods and Procedures: We studied weight gain and risk of a large gain (≥90th percentile) over 3 years in a cohort study of 11, 687 U.S. men and women, 45 to 64 years old, with focus on the 2664 who continued and the 493 who quit smoking.

Results: Among new quitters, adjusted weight gain for those in the highest (vs. lowest) quartile of leukocytes was 0.56 kg/yr more (95% confidence interval, 0.17 to 0.95); for those in the highest (vs. lowest) quartile of fibrinogen, 0.60 kg/yr more (95% confidence interval, 0.27 to 0.92; p = 0.02 and 0.001 for adjusted smoking status by leukocyte and smoking status by fibrinogen interaction terms, respectively). In adjusted analyses, the odds ratio for a large gain associated with quitting (vs. continuing) was 6.2 for those in the highest quartile of leukocytes vs. 2.2 for those in the lowest leukocyte quartile (p = 0.03 for smoking status by inflammatory marker interaction). Similarly, the odds ratio for a large gain associated with quitting was 4.5 in the highest fibrinogen quartile vs. 2.5 in the lowest (p = 0. 09 for the interaction term).

Discussion: Weight gain after smoking cessation is increased in those with higher baseline levels of leukocytes and fibrinogen. These findings suggest a close relationship between inflammatory mediators and regulators of energy balance that may have important clinical implications.
Leptin Expression in Hypothalamic PVN Reverses Dietary Obesity and Hyperinsulinemia but Stimulates Ghrelin*
Authors: Bagnasco Michela , Dube Michael G. , Katz Adi , Kalra Pushpa S. , Kalra Satya P.
Published: April 2008

Objective: In order to circumvent the multiple peripheral effects of hyperleptinemia and leptin resistance, the efficacy of leptin transgene expression in the hypothalamic paraventricular nucleus (PVN) to reinstate the central energy homeostasis in obesity was examined.

Research Methods and Procedures: A recombinant adeno‐associated viral vector encoding either leptin (rAAV‐lep) or green fluorescent protein (rAAV‐GFP) was microinjected into the PVN of obesity‐prone rats consuming a high‐fat diet (HFD).

Results: rAAV‐lep, and not rAAV‐GFP, microinjection significantly reduced energy intake and enhanced energy expenditure, thereby resulting in normalization of weight and blood levels of leptin, insulin, free fatty acids, and glucose concomitant with enhanced ghrelin secretion during the extended period of observation.

Discussion: Thus, we show, for the first time, that amelioration of leptin insufficiency with enhanced localized leptin availability in the PVN alone can reverse dietary obesity and the attendant hyperinsulinemia and concurrently block the central stimulatory effects of elevated endogenous ghrelin on food intake and adiposity.
Comparison of Hologic QDR‐1000/W and 4500W DXA Scanners in 13‐ to 18‐Year Olds
Authors: Litaker Mark S. , Barbeau Paule , Humphries Matthew C. , Gutin Bernard
Published: April 2008

Objective: Body composition measurements made using Hologic QDR‐1000/W pencil‐beam and QDR‐4500W fan‐beam scanners (Bedford, MA) were compared in a sample of 13‐ to 18‐year‐old white and black youth (n = 219).

Research Methods and Procedures: Total fat (FAT), fat‐free soft tissue (FFST), bone mineral content (BMC), bone mineral density (BMD), and percent body fat (%BF) were compared between repeated measurements using the QDR‐4500 and between the two scanners using mixed model ANOVA. Intraclass correlation coefficients and Bland‐Altman limits of agreement were used to evaluate inter‐ and intrascanner reliability.

Results: Intraclass correlation coefficients for repeated measurements using the QDR‐4500 ranged from 0.997 to 0.999 for FAT, %BF, FFST, and BMC and 0.987 for BMD. Mean measurements made using the two scanners differed significantly for FAT, %BF, BMC, and BMD (p < 0.0001), and scan by sex interactions were significant (all p < 0.0005). There were no significant differences in mean measurements between repeat scans using the QDR‐4500 (all p > 0.19). Limits of agreement for measurements of FAT, FFST, and %BF made using the two scanners were approximately three times as wide as those for two measurements using the QDR‐4500. For lower values of FAT and %BF, the QDR‐4500 gave higher measurements than the QDR‐1000, whereas at higher values, this relationship was reversed. The QDR‐1000 tended to give higher BMC measurements, with larger differences for higher values.

Discussion: Using different models of DXA scanners within a study may reduce precision of body composition measurement. This issue needs to be considered in the design of longitudinal studies.
Lifestyle Intervention According to General Recommendations Improves Glucose Tolerance
Authors: Mensink Marco , Blaak Ellen E. , Corpeleijn Eefje , Saris Wim H. , de Bruin Tjerk W. , Feskens Edith J.
Published: April 2008

Objective: Changing dietary and physical activity habits has the potential to postpone or prevent the development of type 2 diabetes. However, it needs to be assessed whether moderate interventions, in agreement with current guidelines for the general population, are effective. We evaluated the impact of a 2‐year combined diet and physical activity intervention program on glucose tolerance in Dutch subjects at increased risk for developing diabetes.

Research Methods and Procedures: Subjects with glucose intolerance were randomly assigned to either the lifestyle intervention group (INT) or control group (CON). The INT received regular dietary advice and was stimulated to increase their physical activity. The CON received a brief leaflet about healthy diet and increased physical activity. Primary outcome measure was the change in glucose tolerance.

Results: In total, 88 subjects completed 2 years of intervention (40 subjects in the INT, 48 subjects in the CON, mean BMI 29.4 kg/m2). Subjects in the INT reduced their body weight, waist circumference, and (saturated) fat intake and improved their aerobic capacity. Two‐hour plasma glucose concentration declined from 8.7 to 8.0 mM in the INT and rose from 8.6 to 9.4 mM in the CON (p < 0.01). Subjects adherent to both the diet and exercise intervention showed the largest reduction in 2‐hour glucose levels.

Discussion: Our results showed that a lifestyle intervention program according to general recommendations improves glucose tolerance, even in a less obese and more physical active population. Furthermore, our results underscore the importance of combining diet and physical activity to improve glucose tolerance and insulin resistance.
The Changing Environment and Population Obesity in the United States
Authors: Jeffery Robert W. , Utter Jennifer
Published: April 2008

The recent unexpected increases in the prevalence of obesity in the United States are widely agreed to be the result of changes in environmental conditions. This paper reviews the available data from diverse sources on environmental factors and obesity. Coverage includes descriptive data on temporal trends in the environment, cross‐sectional and longitudinal studies of the association between environmental exposures and body weight, and experimental trials that have related environmental factors thought to be potentially important in influencing energy intake and expenditure and body weight. Over the period covered by the “obesity epidemic,” a variety of environmental factors have changed dramatically. Some would seem to favor increased body weight (e.g., increased availability of convenience foods and increased use of automobiles and televised entertainment), and others would seem to favor decreased body weight (e.g., a lower‐fat food supply and the increased availability of some forms of physical activity). Definitive conclusions about the relative contributions of energy intake and expenditure to increasing body weight or about the contribution of specific environmental exposures to increasing body weight are far from clear. Increased sophistication in methods for making valid inferences from existing environmental data would be helpful. Even more important, given the urgency of the problem, is experimental research on the question of what environmental changes would be necessary to reverse the obesity epidemic.
Self‐Regulation of Energy Intake in the Prevention and Treatment of Obesity: Is It Feasible?
Authors: Lowe Michael R.
Published: April 2008

The prevalence of obesity in developed countries has been steadily increasing. Comprehensive lifestyle change programs for the treatment of obesity have garnered considerable empirical support, but most weight lost in lifestyle interventions is regained within several years. The outcome of obesity prevention programs has also been disappointing. One reason for this state of affairs may be that most weight control programs are based on an assumption of equipotentiality of their intervention components. That is, obesity prevention and treatment programs consist of a multitude of behavioral, cognitive, nutritional, physical activity, and interpersonal techniques, all of which are assumed to be of roughly equal importance in weight control. However, there is considerable evidence that our evolutionary heritage has made most humans highly sensitive to the availability and nature of food in the environment. It therefore may be unrealistic to expect that enhancing self‐regulatory skills will be sufficient to overcome the combined influence of our appetitive predispositions and the obesigenic environment. However, there is growing evidence that weight control interventions that focus on the availability, structure, composition, and portion size of foods in the diet improve long‐term weight control. Concerted efforts to change the availability and nature of foods at both the individual and population level may hold considerable promise for the treatment and prevention of obesity.