bluuebunny/crossref_metadata_2025_split huggingface dataset:
The energy expenditure of using a “walk-and-work” desk for office workers with obesity
Authors: Levine James A , Miller Jennifer M 
Published: May 2007

Objective:For many people, most of the working day is spent sitting in front of a computer screen. Approaches for obesity treatment and prevention are being sought to increase workplace physical activity because low levels of physical activity are associated with obesity. Our hypothesis was that a vertical workstation that allows an obese individual to work while walking would be associated with significant and substantial increases in energy expenditure over seated work.Methods:The vertical workstation is a workstation that allows an office worker to use a standard personal computer while walking on a treadmill at a self-selected velocity. 15 sedentary individuals with obesity (14 women, one man; 43 (7.5) years, 86 (9.6) kg; body mass index 32 (2.6) kg/m2) underwent measurements of energy expenditure at rest, seated working in an office chair, standing and while walking at a self-selected speed using the vertical workstation. Body composition was measured using dualxray absorptiometry.Results:The mean (SD) energy expenditure while seated at work in an office chair was 72 (10) kcal/h, whereas the energy expenditure while walking and working at a self-selected velocity of 1.1 (0.4) mph was 191 (29) kcal/h. The mean (SD) increase in energy expenditure for walking-and-working over sitting was 119 (25) kcal/h.Conclusions:If sitting computer-time were replaced by walking-and-working, energy expenditure could increase by 100 kcal/h. Thus, if obese individuals were to replace time spent sitting at the computer with walking computer time by 2–3 h/day, and if other components of energy balance were constant, a weight loss of 20–30 kg/year could occur.
OPTIMAL CONSTRUCTION OF SENSE OF DIRECTION IN A TORUS BY A MOBILE AGENT
Authors: BECHA HANANE , FLOCCHINI PAOLA 
Published: May 2007

Sense of direction is a property of the edge-labeling of a network whose availability facilitates computations and often decreases their complexity. In this paper we consider the problem of providing a sense of direction to an anonymous, unoriented torus. The edges of the torus are initially labeled arbitrarily, and they have to be relabeled with a classical compass sense of direction. We first describe an algorithm where the relabeling of the edges is performed by a mobile agent that carries a token. The algorithm is optimal both in terms of number of tokens (with no tokens the task cannot be performed), and in terms of number of moves. We then show that the same technique can be used to orient the torus in the classical message-passing environment, thus obtaining an orientation algorithm that improves all the existing ones in this setting.
DECONTAMINATING CHORDAL RINGS AND TORI USING MOBILE AGENTS
Authors: FLOCCHINI PAOLA , HUANG MIAO JUN , LUCCIO FLAMINIA L. 
Published: May 2007

In this paper we consider a network where an intruder is moving "contaminating" the nodes it passes by, and we focus on the problem of decontaminating such a network by a team of mobile agents. The contamination/decontamination process has the following asynchronous dynamics: when the team is deployed all nodes are assumed to be contaminated, when an agent transits on a node, it will clean the node, when the node is left with no agent, the node will be recontaminated as soon as at least one of its neighbours is contaminated. We study the problem in asynchronous chordal ring networks and in tori. We consider two variations of the model: one where agents have only local knowledge, the other in which they have "visibility", i.e., they can "see" the state of their neighbouring nodes. We first derive lower bounds on the minimum number of agents necessary for the decontamination. In the case of chordal rings we show that the number of agents necessary to perform the cleaning does not depend on the size of the network; in fact it is linear in the length of the longest chord (provided that it is not too long). In the case of a torus, the minimum number of agents is equal to 2 · h, where h is the smallest dimension. We then propose optimal strategies for decontamination and we analyse the number of moves and the time complexity of the decontamination algorithms, showing that the visibility assumption allows us to decrease substantially both complexity measures. Another advantage of the "visibility model" is that agents move independently and autonomously without requiring any coordination.
PHOTOLUMINESCENCE OF A HIGH MOBILITY 2DEG IN THE FRACTIONAL QUANTUM HALL EFFECT REGIME
Authors: SMIRNOV D. , RUDENKOV V. V. , ASHKINADZE B. M. , COHEN E. , CHRISTIANEN P. C. M. , MAAN J. C. , PFEIFFER L. N. 
Published: May 2007

The magneto-PL spectra of modulation-doped, ultra-high mobility GaAs/AlGaAs single heterojunctions (HJs) were studied under a perpendicularly applied magnetic field up to 33 T and at temperatures of 0.3 and 1.2 K. The spectra show remarkable intensity redistribution between free (bulk) exciton and 2DEG-hole PL channels occurring at electron filling factors, ν = 2 and 1. At 0.3 K, significant 2DEG-hole PL spectral changes are observed near ν = 2/3 and 1/3. Several heterojunctions with 2DEG density in the range of n2D - (1 - 2.7) · 1011 cm -2 display similar features. These spectral peculiarities are attributed to the modification of the 2DEG energy spectrum caused by the e-e interaction, in particular, the recombination of valence hole with the composite (fractionally-charged) particles of the magnetized 2DEG. In HJs with lower n2D < 1011 cm -2, the observed PL evolution at ν < 1 is mainly determined by an intensity redistribution between the σ+ and σ- circularly-polarized free exciton PL components. In this case, the exciton energy is lower than the energy of the 2DEG-hole system, so that the free excitons do not dissociate near the magnetized 2DEG and thus, the 2DEG-hole PL is barely observed.
MICROWAVE-MODULATED PHOTOLUMINESCENCE OF A TWO-DIMENSIONAL ELECTRON GAS
Authors: ASHKINADZE B. M. , LINDER E. , COHEN E. , PFEIFFER L. N. 
Published: May 2007

The primary effect of microwave (mw) irradiation on a two dimensional electron gas (2DEG) is heating due to mw absorption by the electrons. At low lattice temperatures, pronounced secondary effects are observed: mw-induced modification of the photoluminescence (PL) spectrum and mw-induced resistance oscillations (MIRO). We present an experimental study of mw-modulated PL (MPL) spectroscopy in modulation-doped GaAs/AlGaAs QW's At low magnetic field strengths (B < 0.5 T ), the analysis of the MPL spectra indicates that they arise of a redistribution of the photoexcited holes within the energy states of the top valence band. This is caused by absorbing low-energy acoustic phonons that are emitted by the mw-heated 2DEG. We propose that these nonequilibrium phonons also affect the 2DEG mobility leading to the MIRO's.For B > 0.5 T and intense mw-irradiation, new optically detected resonances (ODRs) are observed at magnetic fields that depend on the 2DEG density and approximately correspond to integer electron filling factors. We argue that these resonances result from a slight 2DEG density increase under mw irradiation with a concurent, low-energy PL spectral shift due to a small bandgap narrowing.
AN EMPIRICAL ANALYSIS OF THE OPEN SOURCE DEVELOPMENT PROCESS BASED ON MINING OF SOURCE CODE REPOSITORIES
Authors: SCOTTO MARCO , SILLITTI ALBERTO , SUCCI GIANCARLO 
Published: May 2007

This paper presents an empirical analysis of the Open Source development process from the point of view of the involvement of the developers in the production process. The study focuses on how developers contribute to projects in terms of involvement, size and kind of their contribution. Data have been collected from 53 Open Source projects and target application domains include different areas: web and application servers, databases, operating systems, and window managers. Collected data include the number of developers, patterns of code modifications, and evolution over the time of size and complexity. The results of this study show evidence that there are recurrent patterns in Open Source software development and these patterns are common to all the projects considered even if there are no superimposed processes for development, application domains are different, and there are contributions from people spread across the world.
Effect of a 12-Month Randomized Clinical Trial of Exercise on Serum Prolactin Concentrations in Postmenopausal Women
Authors: Tworoger Shelley S. , Sorensen Bess , Chubak Jessica , Irwin Melinda , Stanczyk Frank Z. , Ulrich Cornelia M. , Potter John , McTiernan Anne 
Published: May 2007

Abstract
Prolactin is associated with an increased risk of postmenopausal breast cancer; however, few modifiable factors are known to reduce prolactin concentrations. Therefore, we examined the effect of a 12-month moderate-intensity exercise intervention on serum prolactin concentrations as a secondary end point (primary end points were estrogens and androgens). We randomly assigned 173 postmenopausal women who were sedentary, overweight (body mass index &gt;24 kg/m2, body fat &gt;33%), ages 50 to 75 years, and not using hormone therapy to an exercise intervention or stretching control group. The intervention was facility- and home-based (45 min, 5 days/wk moderate-intensity sports/recreational exercise). One hundred and seventy (98%) women completed the study. Prolactin concentrations were similar at baseline (P = 0.25, geometric mean exercisers = 6.9 and controls = 7.5 ng/mL). Overall, the intervention was not associated with changes in prolactin concentrations between exercisers and controls at 3 months (P = 0.46) or 12 months (P = 0.29). The intervention effect did not vary by baseline age, body mass index, parity, or change in percent body fat during the intervention. Among exercisers, there was a significant difference in prolactin concentrations by change in fitness (VO2max) between baseline and 12 months. Exercisers whose VO2max changed by &lt;5% had a 5% increase in prolactin concentrations, whereas those who increased their VO2max by 5% to 15% and &gt;15% had a 11% (P = 0.03) and 7% (P = 0.01) decrease in prolactin concentrations, respectively. Although the exercise intervention had little effect on prolactin concentrations overall, increasing physical fitness was associated with reduced prolactin concentrations among postmenopausal women. (Cancer Epidemiol Biomarkers Prev 2007;16(5):895–9)
Recreational Physical Activity and Mammographic Breast Density Characteristics
Authors: Reeves Katherine W. , Gierach Gretchen L. , Modugno Francesmary 
Published: May 2007

Abstract
Increased mammographic breast density is considered an intermediate marker of breast cancer risk. Physical activity is believed to reduce breast cancer risk; however, its effect on breast density is not well understood. We studied the association between recreational physical activity and mammographic characteristics of the breast among a population of premenopausal and postmenopausal women enrolled as controls (n = 728) in a case-control study of mammographic breast density and breast cancer. Women were enrolled shortly after obtaining their regular screening mammograms, and participants reported their current and lifetime recreational physical activity history using a self-administered, reliable questionnaire at study enrollment. Linear regression was used to determine associations between physical activity variables and the dense breast area, non-dense area, total breast area, and percent density. Age-adjusted analyses revealed significant inverse associations between physical activity variables and the non-dense area and total area and positive associations with percent breast density. These associations were attenuated and nonsignificant after adjustment for body mass index (BMI). Adjustment for additional factors did not substantially change the results. Physical activity was not associated with the dense breast area before or after adjustment for BMI. Self-reported recreational physical activity was not significantly associated with the mammographic characteristics of the breast after adjustment for BMI in this population. These results suggest that the mechanism by which physical activity reduces breast cancer risk may not involve breast density. (Cancer Epidemiol Biomarkers Prev 2007;16(5):934–42)
Usual Physical Activity and Endogenous Sex Hormones in Postmenopausal Women: The European Prospective Investigation into Cancer–Norfolk Population Study
Authors: Chan Mei-Fen , Dowsett Mitch , Folkerd Elizabeth , Bingham Sheila , Wareham Nicholas , Luben Robert , Welch Ailsa , Khaw Kay-Tee 
Published: May 2007

Abstract
Background: Short-term trials indicate that intensive physical activity may influence endogenous sex hormone concentrations. However, the relationship between usual daily physical activity and endogenous hormones in postmenopausal women in the general population is still uncertain.
Objective and Methods: To determine the relationship between usual physical activity and endogenous sex hormones in postmenopausal women. A cross-sectional population-based study of 2,082 postmenopausal women ages 55 to 81 years, residing in the general community of Norfolk, United Kingdom, and not currently using hormone replacement therapy were chosen to participate. Physical activity in the past 1 year was assessed using a validated questionnaire, and endogenous sex hormone and sex hormone–binding globulin (SHBG) concentrations were determined.
Results: Usual physical activity levels were inversely associated with circulating concentrations of testosterone and estradiol, testosterone/SHBG ratio, and positively associated with SHBG. These associations were only slightly attenuated after adjusting for potential covariates including body mass index, smoking status, alcohol intake, and reproductive variables. Testosterone concentrations and testosterone/SHBG ratios were 19% [95% confidence interval (95% CI), 9-27%, P &lt; 0.001] and 24.0% (95% CI, 13-34% P &lt; 0.001) lower, respectively, whereas estradiol concentrations were 6% (95% CI, 0-12%; P &lt; 0.05) lower in the highest compared with lowest activity levels, respectively. A decreasing trend for the estradiol/SHBG ratio and 17α-hydroxyprogesterone concentrations was also observed. Androstenedione levels did not differ significantly according to physical activity.
Conclusions: Higher usual physical activity levels among postmenopausal women seem to be related to lower endogenous testosterone and estradiol concentrations. This may be one mechanism that could partly explain the reported inverse relationship between physical activity and breast cancer risk in some studies. (Cancer Epidemiol Biomarkers Prev 2007;16(5):900–905)
Evaluation of Genetic Variations in the Androgen and Estrogen Metabolic Pathways as Risk Factors for Sporadic and Familial Prostate Cancer
Authors: Cunningham Julie M. , Hebbring Scott J. , McDonnell Shannon K. , Cicek Mine S. , Christensen G. Bryce , Wang Liang , Jacobsen Steven J. , Cerhan James R. , Blute Michael L. , Schaid Daniel J. , Thibodeau Stephen N. 
Published: May 2007

AbstractPrevious studies suggest that enzymes involved in the androgen metabolic pathway are susceptibility factors for prostate cancer. Estrogen metabolites functioning as genotoxins have also been proposed as risk factors. In this study, we systematically tested the hypothesis that common genetic variations for those enzymes involved in the androgen and estrogen metabolic pathways increase risk for sporadic and familial prostate cancer. From these two pathways, 46 polymorphisms (34 single nucleotide polymorphisms, 10 short tandem repeat polymorphisms, and 2 null alleles) in 25 genes were tested for possible associations. Those genes tested included PRL, LHB, CYP11A1, HSD3B1, HSD3B2, HSD17B2, CYP17, SRD5A2, AKR1C3, UGT2B15, AR, SHBG, and KLK3 from the androgen pathway and CYP19, HSD17B1, CYP1A1, CYP1A2, CYP1B1, COMT, GSTP1, GSTT1, GSTM1, NQO1, ESR1, and ESR2 from the estrogen pathway. A case-control study design was used with two sets of cases: familial cases with a strong prostate cancer family history (n = 438 from 178 families) and sporadic cases with a negative prostate cancer family history (n = 499). The controls (n = 493) were derived from a population-based collection. Our results provide suggestive findings for an association with either familial or sporadic prostate cancer with polymorphisms in four genes: AKR1C3, HSD17B1, NQO1, and GSTT1. Additional suggestive findings for an association with clinical variables (disease stage, grade, and/or node status) were observed for single nucleotide polymorphisms in eight genes: HSD3B2, SRD5A2, SHBG, ESR1, CYP1A1, CYP1B1, GSTT1, and NQO1. However, none of the findings were statistically significant after appropriate corrections for multiple comparisons. Given that the point estimates for the odds ratio for each of these polymorphisms are &lt;2.0, much larger sample sizes will be required for confirmation. (Cancer Epidemiol Biomarkers Prev 2007;16(5):969–78)
Concordance of Pharmacogenetic Polymorphisms in Tumor and Germ Line DNA in Adult Patients with Acute Myeloid Leukemia
Authors: Weiss Joli R. , Baer Maria R. , Ambrosone Christine B. , Blanco Javier G. , Hutson Alan , Ford Laurie A. , Moysich Kirsten B. 
Published: May 2007

Abstract
Archived tumor tissue is a useful resource for retrospective studies addressing relationships between genetic polymorphisms and treatment outcomes. However, genotypes determined in tumor and somatic tissues may differ due to cytogenetic and molecular changes associated with malignant transformation and progression. Discordance between germ line and tumor genotypes may be particularly relevant in leukemia because cytogenetic abnormalities are frequent. We compared genotypes determined in DNA extracted from paired pretreatment bone marrow and buccal samples from 80 adult patients with acute myeloid leukemia (AML). Paired AML and buccal DNA samples were genotyped for polymorphisms (21 single nucleotide polymorphisms and 2 gene deletions) on genes encoding proteins involved in drug metabolism (CYP3A4, CYP2C8, CDA, and GSTP1), oxidative stress mechanisms (CAT, MnSOD, GSTT1, GSTM1, GSTA1, and GPX1), drug transport (MDR1, MRP1, and BCRP), and DNA repair (MGMT, XPD, and XRCC1). Genotypes were determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, except GSTM1 and GSTT1, for which deletion genotypes were determined using multiplex PCR. Concordance of genotypes was tested by κ statistics. κ statistics for paired AML and buccal DNA samples ranged between 0.94 and 1.00, indicating excellent agreement. The GSTT1 and GSTM1 genotypes were in perfect concordance for the paired samples. Agreement was also excellent for genes at AML chromosome deletion and translocation breakpoints, including MDR1 at 7q21.1 and MRP1 at 16p13.1. Based on these data, genotypes derived from archived AML bone marrow samples were not likely to differ from those from genomic DNA, and archived bone marrow samples may be useful for the conduct of retrospective pharmacogenetic studies. (Cancer Epidemiol Biomarkers Prev 2007;16(5):1038–41)
Lactase Persistence, Dietary Intake of Milk, and the Risk for Prostate Cancer in Sweden and Finland
Authors: Torniainen Suvi , Hedelin Maria , Autio Ville , Rasinperä Heli , Bälter Katarina Augustsson , Klint Åsa , Bellocco Rino , Wiklund Fredrik , Stattin Pär , Ikonen Tarja , Tammela Teuvo L.J. , Schleutker Johanna , Grönberg Henrik , Järvelä Irma 
Published: May 2007

Abstract
Prostate carcinoma is the most common cancer in men. Its primary pathogenesis is mostly unknown. Dairy products containing lactose have been suggested to be risk factors for prostate cancer. Digestion of lactose is dependent on lactase activity in the intestinal wall. A single nucleotide polymorphism C to T residing 13,910 bp upstream of the lactase gene has been shown to associate with the developmental down-regulation of lactase activity underlying persistence/nonpersistence trait. To find out whether lactase persistence is related to the risk for prostate cancer, we genotyped 1,229 Finnish and 2,924 Swedish patients and their 473 Finnish and 1,842 Swedish controls using solid-phase minisequencing. To explore if dairy products have an association with prostate cancer, we analyzed the milk consumption in the Swedish study consisting of 1,499 prostate cancer patients and 1,130 controls (Cancer Prostate in Sweden I study) using a questionnaire. Only the consumption of low-fat milk was found to be associated with increased risk of prostate cancer [odds ratio (OR), 1.73; 95% confidence interval (95% CI), 1.16-2.39]. A statistically significantly higher (P &lt; 0.01) lactose intake was observed among subjects with high lactase activity (C/T and T/T genotypes) compared with those with low lactase activity (C/C genotype). Lactase persistence did not associate with increased risk for prostate carcinoma in the Finnish (OR, 1.11; 95% CI, 0.83-1.47; P = 0.488) or in the Swedish populations (OR, 1.16; 95% CI, 0.91-1.46; P = 0.23). In conclusion, lactase persistence/nonpersistence contains no risk for prostate cancer. Analysis of different milk products showed some evidence for low-fat milk as a potential risk factor for prostate cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(5):956–61)
Polymorphisms in the CYP19A1 (Aromatase) Gene and Endometrial Cancer Risk in Chinese Women
Authors: Tao Meng Hua , Cai Qiuyin , Zhang Zuo-Feng , Xu Wang-Hong , Kataoka Nobuhiko , Wen Wanqing , Xiang Yong-Bing , Zheng Wei , Shu Xiao Ou 
Published: May 2007

Abstract
Aromatase, encoded by the CYP19A1 gene, is a key enzyme in estradiol biosynthesis, which catalyzes the conversion of androstenedione and testosterone to estrone and estradiol, respectively. Given the critical role of estrogen in the development of endometrial cancer risk, we evaluated genetic polymorphisms of the CYP19A1 gene, including rs1065779, rs700519, rs28566535, rs752760, and rs1870050, in association with endometrial cancer in a population-based case-control study conducted in Shanghai, China. Genotypes of 1,040 incident endometrial cancer cases and 1,031 frequency-matched controls were included in the study. We applied a logistic regression model to derive adjusted odds ratios (OR) and their 95% confidence intervals (95% CI). Six common haplotypes with a frequency ≥5% were estimated; the highest frequency haplotype was GCACA (27.8% in cases and 26.2% in controls). We observed an inverse association between CYP19A1 haplotype TCATC and endometrial cancer in our population (OR, 0.76; 95% CI, 0.62-0.92). An inverse association was found between endometrial cancer and single nucleotide polymorphism rs1870050 in the promoter region with ORs of 0.81 (95% CI, 0.68-0.97) and 0.58 (95% CI, 0.42-0.80) for the AC and CC genotypes, respectively. We observed a multiplicative interaction between single nucleotide polymorphism rs700519 and body mass index among postmenopausal women (P = 0.01), with stronger associations between rs700519 genotypes and endometrial cancer risk among heavier (body mass index, ≥25) postmenopausal women. In summary, our data show that polymorphisms in the CYP19A1 gene may contribute to endometrial carcinogenesis. (Cancer Epidemiol Biomarkers Prev 2007;16(5):943–9)