bluuebunny/crossref_metadata_2025 huggingface dataset:
Genome Sequence of
Aedes aegypti
, a Major Arbovirus Vector
Authors: Nene Vishvanath , Wortman Jennifer R. , Lawson Daniel , Haas Brian , Kodira Chinnappa , Tu Zhijian (Jake) , Loftus Brendan , Xi Zhiyong , Megy Karyn , Grabherr Manfred , Ren Quinghu , Zdobnov Evgeny M. , Lobo Neil F. , Campbell Kathryn S. , Brown Susan E. , Bonaldo Maria F. , Zhu Jingsong , Sinkins Steven P. , Hogenkamp David G. , Amedeo Paolo , Arensburger Peter , Atkinson Peter W. , Bidwell Shelby , Biedler Jim , Birney Ewan , Bruggner Robert V. , Costas Javier , Coy Monique R. , Crabtree Jonathan , Crawford Matt , deBruyn Becky , DeCaprio David , Eiglmeier Karin , Eisenstadt Eric , El-Dorry Hamza , Gelbart William M. , Gomes Suely L. , Hammond Martin , Hannick Linda I. , Hogan James R. , Holmes Michael H. , Jaffe David , Johnston J. Spencer , Kennedy Ryan C. , Koo Hean , Kravitz Saul , Kriventseva Evgenia V. , Kulp David , LaButti Kurt , Lee Eduardo , Li Song , Lovin Diane D. , Mao Chunhong , Mauceli Evan , Menck Carlos F. M. , Miller Jason R. , Montgomery Philip , Mori Akio , Nascimento Ana L. , Naveira Horacio F. , Nusbaum Chad , O'Leary Sinéad , Orvis Joshua , Pertea Mihaela , Quesneville Hadi , Reidenbach Kyanne R. , Rogers Yu-Hui , Roth Charles W. , Schneider Jennifer R. , Schatz Michael , Shumway Martin , Stanke Mario , Stinson Eric O. , Tubio Jose M. C. , VanZee Janice P. , Verjovski-Almeida Sergio , Werner Doreen , White Owen , Wyder Stefan , Zeng Qiandong , Zhao Qi , Zhao Yongmei , Hill Catherine A. , Raikhel Alexander S. , Soares Marcelo B. , Knudson Dennis L. , Lee Norman H. , Galagan James , Salzberg Steven L. , Paulsen Ian T. , Dimopoulos George , Collins Frank H. , Birren Bruce , Fraser-Liggett Claire M. , Severson David W.
Published: May 2007

We present a draft sequence of the genome of
Aedes aegypti
, the primary vector for yellow fever and dengue fever, which at ∼1376 million base pairs is about 5 times the size of the genome of the malaria vector
Anopheles gambiae
. Nearly 50% of the
Ae. aegypti
genome consists of transposable elements. These contribute to a factor of ∼4 to 6 increase in average gene length and in sizes of intergenic regions relative to
An. gambiae
and
Drosophila melanogaster
. Nonetheless, chromosomal synteny is generally maintained among all three insects, although conservation of orthologous gene order is higher (by a factor of ∼2) between the mosquito species than between either of them and the fruit fly. An increase in genes encoding odorant binding, cytochrome P450, and cuticle domains relative to
An. gambiae
suggests that members of these protein families underpin some of the biological differences between the two mosquito species.
Combined Action of PHD and Chromo Domains Directs the Rpd3S HDAC to Transcribed Chromatin
Authors: Li Bing , Gogol Madelaine , Carey Mike , Lee Daeyoup , Seidel Chris , Workman Jerry L.
Published: May 2007

Nucleosomes must be deacetylated behind elongating RNA polymerase II to prevent cryptic initiation of transcription within the coding region. RNA polymerase II signals for deacetylation through the methylation of histone H3 lysine 36 (H3K36), which provides the recruitment signal for the Rpd3S histone deacetylase complex (HDAC). The recognition of methyl H3K36 by Rpd3S requires the chromodomain of its Eaf3 subunit. Paradoxically, Eaf3 is also a subunit of the NuA4 acetyltransferase complex, yet NuA4 does not recognize methyl H3K36 nucleosomes. In
Saccharomyces cerevisiae
, we found that methyl H3K36 nucleosome recognition by Rpd3S also requires the plant homeobox domain (PHD) of its Rco1 subunit. Thus, the coupled chromo and PHD domains of Rpd3S specify recognition of the methyl H3K36 mark, demonstrating the first combinatorial domain requirement within a protein complex to read a specific histone code.
Comment on "A Centrosome-Independent Role for γ-TuRC Proteins in the Spindle Assembly Checkpoint"
Authors: Taylor Stephen S. , Hardwick Kevin G. , Sawin Kenneth E. , Biggins Sue , Piatti Simonetta , Khodjakov Alexey , Rieder Conly L. , Salmon Edward D. , Musacchio Andrea
Published: May 2007

Müller
et al
. (Reports, 27 October 2006, p. 654) showed that inhibition of the γ-tubulin ring complex (γ-TuRC) activates the spindle assembly checkpoint (SAC), which led them to suggest that γ-TuRC proteins play molecular roles in SAC activation. Because γ-TuRC inhibition leads to pleiotropic spindle defects, which are well known to activate kinetochore-derived checkpoint signaling, we believe that this conclusion is premature.
Comment on "A Centrosome-Independent Role for γ-TuRC Proteins in the Spindle Assembly Checkpoint"
Authors: Weaver Beth A. A. , Cleveland Don W.
Published: May 2007

Müller
et al
. (Reports, 27 October 2006, p. 654) proposed a role for microtubule nucleation in mitotic checkpoint signaling. However, their observations of spindle defects and mitotic delay after depletion of γ-tubulin ring complex (γ-TuRC) components are fully consistent with activation of the established pathway of checkpoint signaling in response to incomplete or unstable interactions between kinetochores of mitotic chromosomes and spindle microtubules.
Sound Production in the Clownfish
Amphiprion clarkii
Authors: Parmentier Eric , Colleye Orphal , Fine Michael L. , Frédérich Bruno , Vandewalle Pierre , Herrel Anthony
Published: May 2007

Although clownfish sounds were recorded as early as 1930, the mechanism of sound production has remained obscure. Yet, clownfish are prolific "singers" that produce a wide variety of sounds, described as "chirps" and "pops" in both reproductive and agonistic behavioral contexts. Here, we describe the sonic mechanism of the clownfish Amphiprion clarkii.
Science, the Fruit of Commerce
Authors: Israel Jonathan I.
Published: May 2007

Matters of Exchange
. Commerce, Medicine, and Science in the Dutch Golden Age.
By Harold J. Cook
. Yale University Press, New Haven, CT, 2007. 576 pp. $35. ISBN 9780300117967.

Cook presents a case for seeing Dutch commerce rather than religion as the crucial inspiration for the rise of science in the 16th and 17th centuries.
Pulmonary O2 uptake on-kinetics in sprint- and endurance-trained athletes
Authors: Berger Nicolas J.A. , Jones Andrew M.
Published: May 2007

Pulmonary O2 uptake kinetics during “step” exercise have not been characterized in young, sprint-trained (SPT), athletes. Therefore, the objective of this study was to test the hypotheses that SPT athletes would have (i) slower phase II kinetics and (ii) a greater oxygen uptake “slow component” when compared with endurance-trained (ENT) athletes. Eight sub-elite SPT athletes (mean ( ± SD) age = 25 (±7) y; mass = 80.3 (±7.3) kg) and 8 sub-elite ENT athletes (age= 28 (±4) y; mass = 73.2 (±5.1) kg) completed a ramp incremental cycle ergometer test, a Wingate 30 s anaerobic sprint test, and repeat “step” transitions in work rate from 20 W to moderate- and severe-intensity cycle exercise, during which pulmonary oxygen uptake was measured breath by breath. The phase II oxygen uptake kinetics were significantly slower in the SPT athletes both for moderate (time constant, τ; SPT 32 (±4) s vs. ENT 17 (±3) s; p < 0.01) and severe (SPT 32 (±12) s vs. ENT 20 (±6) s; p < 0.05) exercise. The amplitude of the slow component (derived by exponential modelling) was not significantly different between the groups (SPT 0.55 (±0.12) L·min–1 vs. ENT 0.50 (±0.22) L·min–1), but the increase in oxygen uptake between 3 and 6 min of severe exercise was greater in the SPT athletes (SPT 0.37 (±0.08) L·min–1 vs. ENT 0.20 (±0.09) L·min–1; p < 0.01). The phase II τ was significantly correlated with indices of aerobic exercise performance (e.g., peak oxygen uptake (moderate-intensity r = –0.88, p < 0.01; severe intensity r = –0.62; p < 0.05), whereas the relative amplitude of the oxygen uptake slow component was significantly correlated with indices of anaerobic exercise performance (e.g., Wingate peak power output; r = 0.77; p < 0.01). Thus, it could be concluded that sub-elite SPT athletes have slower phase II oxygen uptake kinetics and a larger oxygen uptake slow component compared with sub-elite ENT athletes. It appears that indices of aerobic and anaerobic exercise performance differentially influence the fundamental and slow components of the oxygen uptake kinetics.
Cycling peak power in obese and lean 6- to 8-year-old girls and boys
Authors: Aucouturier Julien , Lazaar Nordine , Doré Eric , Meyer Martine , Ratel Sebastien , Duché Pascale
Published: May 2007

The purpose of this study was to investigate the possible effect of the difference in percentage body fat (%BF) and fat-free mass (FFM) on cycling peak power (CPP) in 6- to 8-year-old obese and lean untrained girls and boys. Obese (35 girls, 35 boys) and lean (35 girls, 35 boys) children were measured for obesity, %BF, calculated from skinfold measurements. FFM was calculated as body mass (BM) minus body fat. A force–velocity test on a cycle ergometer was used to measure CPP. CPP was related to anthropometric variables using standard and allometric models. CPP in absolute terms was higher in obese children than in lean children irrespective of gender. BM-related CPP was significantly lower in obese children than in lean ones, whereas no effect of obesity appeared on FFM-related CPP. Velocity at CPP (Vopt) was significantly lower and force at CPP (Fopt) was significantly higher in girls than in boys. Muscle power production was unaffected by obesity in children. Low BM-related CPP could explain the difficulty of taking up physical activities that are body-mass related in obese children. Gender difference for Vopt and Fopt shows that girls and boys may have different maturation patterns affecting CPP.
Relationship between metabolic function and skeletal muscle fatigue during a 90 s maximal isometric contraction
Authors: Sirikul Bovorn , Hunter Gary R. , Larson-Meyer D. Enette , Desmond Renee , Newcomer Bradley R.
Published: May 2007

Little is known concerning the contributions of oxidative phosphorylation (OxPhos), anaerobic glycolytic rate (AnGly), maximum creatine kinase (CK) activity, and metabolic economy (ME) on fatigue resistance. The purpose of this study was to model fatigue using muscle tissue metabolic measures during a maximal short-duration isometric contraction. Muscle metabolic function was measured with [31P]-magnetic resonance spectroscopy (MRS) in 54 premenopausal women (age: 33.8 ± 6.3 y) while they performed 100% isometric plantar flexions. Multiple regression analysis revealed that all metabolic variables were independent predictors of fatigue resistance after adjusting for maximum isometric force generated (R2= 0.56). ME accounted for the largest portion (36%) of overall shared variance. OxPhos accounted for the most shared variance of the three energy systems. These results support previous findings that OxPhos, AnGly, CK, and ME all contribute to fatigue resistance over a short duration. Additionally, the continued activity of CK at the end of 90 s of maximal exercise lends support to the concept of a CK shuttle facilitating energy transfer within the mitochondria.
Trends in physical activity research in Canada
Authors: Herman Katya M. , Ardern Chris I. , Mason Caitlin , Brien Susan E. , Katzmarzyk Peter T.
Published: May 2007

The purpose of this study was to assess Canada’s physical activity research productivity by (i) assessing Canada’s contribution to global physical activity research, (ii) determining trends in Canadian physical activity research over time, and (iii) identifying research areas of greater or lesser representation. A Medline search was performed to identify physical activity research published between 1990 and 2005 from Canadian institutions or using Canadian data. Trends over time were plotted and compared with global physical activity research patterns. Original and review articles were sorted based on subject characteristics, nature of physical activity contribution, province and institution of origin, and research area or “pillar”. A total of 5302 Canadian physical activity articles were identified for the period 1990–2005, representing 4.9% of global physical activity research. After manual sorting of abstracts, 3829 relevant articles were included for further analysis. A majority of Canada’s physical activity research has come from Ontario (49%), followed by Quebec (21%), Alberta (10%), and British Columbia (10%). Where physical activity was the primary research focus, the biomedical and clinical pillars each accounted for 39% of Canadian research, with lesser contributions from population health (14%) and health services (2%). Physical activity research productivity in Canada has paralleled global trends over the last 15 years. There is currently less physical activity research being conducted in population health and health services than in the biomedical and clinical areas; however, these areas play an important role in the development of public health policy and programs targeted at reducing the burden of physical inactivity and obesity in Canada.
The effect of pedometer position and normal gait asymmetry on step count accuracy
Authors: Horvath Sylvia , Taylor David G. , Marsh Jonathan P. , Kriellaars Dean J.
Published: May 2007

Manufacturers of pedometers recommend wearing a pedometer on the midline of the right thigh and this recommendation is used in research. However, there is conflicting evidence regarding the effect of pedometer position on accuracy. The purpose of this study was to systematically evaluate the effect of pedometer position on accuracy for 3 modes of gait. The Yamax SW200 pedometer was evaluated in 20 subjects in 5 different positions simultaneously: left mid-axillary, left mid-thigh, umbilical, right mid-thigh, and right mid-axillary. Each subject was asked to walk on a treadmill (54, 80, and 107 m·min–1), to walk overground (slow, preferred, and fast speeds), and to ascend and descend stairs. Pedometer steps were recorded and compared with actual steps observed. Using the same protocol, instantaneous triaxial accelerometry was used to explain position-dependent differences in accuracy. At slow speeds, the left mid-axillary position demonstrated the lowest net mean (±SD) error across all modes of gait (7.7% (±11.6%%) overground; –0.6% (±2.2%) stairs). The right mid-thigh position had significantly (p < 0.01) higher error for treadmill (18.1% (±17.3%)), overground (12.9% (±15.2%)), and stairs (2.9% (±3.9%)). Pedometer position dependent error was demonstrated, with the left mid-axillary position superior to the recommended position of right mid-thigh. The greater accuracy on the left side was wholly explained by gait asymmetry evident in step-induced accelerations recorded at right and left pedometer positions. A model of absolute error based on the ratio of steps at different gait speeds was generated to demonstrate the importance of this finding in pedometer-based lifestyle intervention studies.
Influence of age and pubertal status on substrate utilization during exercise with and without carbohydrate intake in healthy boys
Authors: Timmons Brian W. , Bar-Or Oded , Riddell Michael C.
Published: May 2007

Substrate utilization during exercise is known to differ between children and adults, but whether these differences are related to pubertal status is unclear. The objective of this study was to investigate the effects of pubertal status on endogenous (CHOendo) and orally ingested exogenous (CHOexo) carbohydrate and fat oxidation rates during exercise. Twenty boys at the same chronological age (12 y) were divided into three pubertal groups (pre-pubertal, PP: n = 7; early-pubertal, EP: n = 7; mid- to late-pubertal, M-LP: n = 6) and consumed either a placebo or13C-enriched 6% CHO drink while cycling for 60 min at ~70% of their maximal aerobic power (VO2 max). Another group of 14-year-old boys (pubertal, n = 9) completed all procedures. Substrate utilization was calculated for the final 15 min of exercise using indirect calorimetry and stable isotope methodology. CHOexodecreased fat (p < 0.001) and increased total CHO (p < 0.001) oxidation, irrespective of group. Fat oxidation was higher (p = 0.01) in younger boys than in older boys, but similar (p ≥ 0.33) among PP, EP, and M-LP boys. CHOexocontributed to ~30% of energy expenditure (EE) in PP and EP, but to only 24% in M-LP (p = 0.02), which was identical to the older boys (24%). CHOexooxidation rate as a percentage of EE was inversely related to testosterone levels (r = −0.51, p = 0.005, n = 29). It was concluded that reliance on CHOexoduring exercise is particularly sensitive to pubertal status, with the highest oxidation rates observed in pre- and early-pubertal boys, independent of chronological age.
Manipulating training intensity and volume in already well-trained rats: effect on skeletal muscle oxidative and glycolytic enzymes and buffering capacity
Authors: Laursen Paul B. , Marsh Susan A. , Jenkins David G. , Coombes Jeff S.
Published: May 2007

Well-trained endurance athletes undergo periods of high-intensity interval training (HIT) or high-volume training (HVT) to improve exercise performance, but little is known about the mechanistic changes that occur during this time. The purpose of this study was to examine the influence of HIT and HVT on the activities of citrate synthase (CS) and phosphofructokinase (PFK), and on intramuscular buffering capacity (βm) in already well-trained rats. At 4 weeks of age, Wistar rats were divided into sedentary (SED; n = 18) and exercise training groups (n = 38). Following a 10 week preliminary training program, trained rats were divided randomly into 3 further groups that completed 4 additional weeks of continued endurance (CON, n = 14), high-intensity training (HIT, n = 12), or high-volume training (HVT, n = 12). Soleus (SOL), red and white gastrocnemius (RG and WG), and red and white vastus (RV and WV) muscles were removed 24–48 h after a final run-to-fatigue performance test (30 m·min–1; 25% grade) to determine the activities of CS, PFK, and βm. No differences in run time to exhaustion were found between the groups. However the HIT group possessed CS and PFK activities and βmin WV muscle that were 60%, 24%, and 10% higher, respectively (all p < 0.05), compared with the HVT group; differences were not found between the HIT and CON groups. Although no differences in run performance were found, HIT compared with HVT in already well-trained rats resulted in significantly higher oxidative and glycolytic capacities of fast-contracting fibres. No differences were shown in fast-contracting muscle between HIT and CON.
Muscle oxygenation during prolonged electrical stimulation-evoked cycling in paraplegics
Authors: Muraki Satoshi , Fornusek Ché , Raymond Jacqui , Davis Glen Macartney
Published: May 2007

This study investigated cardiorespiratory responses and muscle oxygenation during prolonged electrical stimulation (ES)-evoked leg cycling in individuals with paraplegia (PARA). Four PARA and 6 able-bodied (AB) persons participated in this study. Subjects performed 10 min of passive cycling and 40 min of active cycling (PARA, ES cycling; AB, voluntary cycling) at workloads selected to elicit an equivalent oxygen uptake between groups. Cycling power output, cardiorespiratory responses, mechanical efficiency, and quadriceps muscle oxygenation (measured with near-infrared spectroscopy) were measured over the duration of the exercise. Oxygen uptake was similar in both groups during active cycling (PARA, 737 ± 177 mL·min–1; AB, 840 ± 90 mL·min–1). The cycling power output for PARA individuals commenced at 8.8 W, but varied considerably over 40 min. PARA individuals demonstrated markedly lower gross mechanical efficiency (~1.3%) during ES cycling compared with AB individuals performing voluntary exercise (~12.6%). During ES cycling, muscle oxygen saturation (SO2) decreased to approximately 72 ± 19%, whereas SO2 during volitional cycling was unaltered from resting levels. Muscle oxygenated haemoglobin initially decreased (–23%) during ES cycling, but returned to resting levels after 10 min. Deoxygenated haemoglobin initially rose during the first 5 min of ES cycling, and remained elevated by 28% thereafter. Upon cessation of ES cycling, lower-limb muscle oxygenation increased (+93%), suggesting reactive hyperaemia in PARA individuals after such exercise. During ES cycling, muscle oxygenation followed a different pattern to that observed in AB individuals performing voluntary cycling at an equivalent VO2. Equilibrium between oxygen demand and oxygen delivery was reached during prolonged ES cycling, despite the lack of neural adjustments of leg vasculature in the paralyzed lower limbs.
Genotype-specific weight loss treatment advice: how close are we?
Authors: Adamo Kristi B. , Tesson Frédérique
Published: May 2007

Obesity, whose prevalence is continually rising, is one of the world’s greatest health care burdens. This multifactorial condition is associated with many obesity-related conditions, such as type 2 diabetes, dyslipidemia, and cardiovascular disease. Weight loss is a significant challenge facing those wishing to reduce their disease risk. Of course, like obesity itself, weight loss is a complex phenomenon dependent on many environmental and genetic influences, and thus individual responses to weight loss interventions are incredibly variable. Currently, there are 3 major interventions used to reduce weight: diet, exercise, and pharmacotherapy. The findings from studies examining gene–diet (nutrigenetic), gene–exercise (actigenetic), and gene–pharmaceutical (pharmacogenetic) interactions, although not clinically applicable at this time, are gaining awareness. This review article summarizes the current evidence to support the contribution of DNA sequence variation in genes related to energy balance (expenditure and intake) in the response to weight loss intervention. There is no doubt that replication using more rigorous study designs that include the study of interactions between multiple genes and interventions is required to move towards the development of genotype-specific weight loss treatment strategies.
Environmental influences on adiponectin levels in humans
Authors: Imbeault Pascal
Published: May 2007

In addition to its classic role in the storage and release of nonesterified fatty acids, the adipocyte is now recognized as a critical source of many endocrine signals. Of these signals, adiponectin has been found to promote lipid oxidation and glucose uptake in skeletal muscles and to reduce glucose output in the liver. Because of the effects of adiponectin on these organs, the search for factors or conditions that could positively influence the synthesis of this adipocyte-derived protein has drawn a great deal of interest. This brief review explores the effects of environmental influences such as weight loss, acute food intake, exercise, and cold exposure on circulating adiponectin levels in humans.
Physical activity in the treatment of obesity: beyond body weight reduction
Authors: Janiszewski Peter M. , Ross Robert
Published: May 2007

The prevalence of obesity is high and continues to increase. Obesity is a leading risk factor for premature mortality and numerous chronic health conditions. The role of physical activity as a treatment and (or) preventive strategy for combating obesity has been the subject of substantial research. Most of this research has focused solely on reductions in total body weight and (or) fat mass as the indicator of treatment success. Because the deposition of fat in the abdomen and nonadipose tissues of the liver and muscle plays a major role in the development of obesity-related health risk, these depots have emerged as alternative targets for obesity treatment. Absent from previous reviews is a detailed consideration of the influence of physical activity on these treatment outcomes. The purpose of this review is to evaluate the independent role of physical activity in the treatment of obesity in a broader context; that is, through its effects on abdominal obesity and liver and muscle fat, in addition to its established effects on body weight and (or) total fat mass. Consideration is also given to the utility of physical activity with minimal or no weight loss in the treatment of obesity.
Appetite control after weight loss: what is the role of bloodborne peptides?
Authors: Doucet Éric , Cameron Jameason
Published: May 2007

The literature presented in this paper argues that our limited ability to maintain energy balance in a weight-reduced state is the product of our difficulty in compensating for the weight loss-induced reduction in total energy expenditure. The end result, translated into the overwhelming complexity of preserving long-term weight loss, is presented as being a consequence of compromised appetite control. Given the present-day food landscape and the resultant susceptibility to passive overconsumption, the focus of this review will be on the peripheral (“bottom-up”) signals (leptin, PYY, ghrelin, and GLP-1) and the evidence highlighting their influence on feeding behaviour. As we continue studying paradigms of body mass reduction, specifically the data emerging from patients of bariatric surgery, it is becoming clearer that counter-regulatory adaptations, possibly through down-(leptin, PYY, and GLP-1) or upregulation (ghrelin) of peptides, have an impact on energy balance. In itself, food deprivation influences some of the peptides that ultimately provide the physiological input for the overt expression of feeding behaviour; these peripheral adaptations are expected to serve as feeding cues — cues that, in the end, can serve to compromise the maintenance of energy balance. In a potentially novel intervention to increase compliance to long-term reductions in energy intake, it is proposed that manipulating the pattern of food intake to favourably alter the profile of gastrointestinal peptides would lead to better dietary control.
Oxygen cost of the CF–DND fire fit test in males and females
Authors: Dreger Randy W. , Petersen Stewart R.
Published: May 2007

The Department of National Defence employs a work-related test circuit comprising 10 various firefighting tasks (FF test) to assess the fitness of incumbent Canadian Forces firefighters. The main purpose of this study was to document the oxygen cost of the FF test over a wide range of performance times. These data were then used to predict the oxygen cost associated with the 8 min completion standard. Finally, we examined the influence of gender on selected physiological responses during the FF test. Thirty male and 23 female subjects practiced the test 3–5 times and then completed, in random order and on separate days, a maximal-effort trial while breathing with either a self-contained breathing apparatus (SCBA) or a portable metabolic measurement system (MMC). The breath-by-breath gas exchange data from the MMC were collapsed into a single value that represented the average oxygen cost for each participant to complete the work simulation. To calculate the average VO2 associated with the 8 min completion time, separate regression lines for test duration and average VO2 were generated for males and females. Analyses of covariance (ANCOVA) revealed that the regression lines for the male and female groups coincided, therefore all data were collapsed. The resulting regression equation predicted that the average VO2 associated with the 8 min standard was 34.1 (± 4.0) mL·kg–1·min–1, and this value appears consistent with other research on the oxygen cost of firefighting. There was no evidence to suggest that the oxygen cost of meeting the 8 min standard was different for males or females.
Interaction of exercise training andn-3 fatty acid supplementation on postprandial lipemia
Authors: Thomas Tom R. , Liu Ying , Linden Melissa A. , Rector R. Scott
Published: May 2007

The effect of combining omega-3 fatty acid (n-3 FA) supplementation and exercise training treatment on postprandial lipemia (PPL) has not been studied. The purpose of this study was to examine the interaction of n-3 FA and exercise training in attenuating PPL after a high-fat meal. Previously sedentary, overweight, subjects (n = 22; 12 women, 10 men, BMI 26.6 ±0.7 kg/m2) were randomly assigned to one of two treatment groups: n-3 FA supplementation alone (FO, n = 10) or n-3 FA supplementation plus exercise training (FO+ExTr, n = 12). Both groups consumed 4 g/d n-3 FA, and one group also exercise trained for 45 min/d, 5d/week of brisk walking and (or) jogging at 60% VO2 max. Before and after 4 weeks of treatment, subjects performed a baseline PPL and a PPL following a single session of exercise (ExPPL). PPL was assessed by triglyceride (TG) area under the curve (AUC) and peak TG response (TGpeak). A two-way analysis of variance (ANOVA) with repeated measures was used to compare results from treatments for baseline and exercise trials. FO alone reduced PPL and Ex PPL, and FO+ExTr attenuated the ExPPL response measured as total AUC and TGpeak. There was no significant main effect for group or group by time interaction for baseline PPL or ExPPL. Fasting high-density lipoprotein cholesterol (HDL-C) and HDL2-C (i.e., subfraction 2) concentrations were significantly increased in the FO+ExTr group after the treatments. These results suggest that n-3 FA supplementation reduced PPL in sedentary subjects. Exercise training has no interference or additive effects with n-3 FA supplementation in attenuating PPL, but combined treatments may be additive in raising high-density lipoprotein cholesterol.
Strategies to enhance compliance to physical activity for patients with insulin resistance
Authors: Kirk Alison , De Feo Pierpaolo
Published: May 2007

The evidence that physical activity is an effective therapeutic tool in the management of insulin resistance and type 2 diabetes is well documented. Limited research has addressed how best to promote and maintain physical activity in these individuals. This paper explores strategies to enhance compliance to physical activity for patients with insulin resistance. Several evidence-based guidelines and reviews recommend that physical activity interventions are based on a valid theoretical framework. However, there is no evidence-based consensus on the best theory or the combination of theories to use. Motivational tools such as pedometers, wearable sensors measuring energy expenditure, and point of choice prompts appear to be effective at stimulating short-term substantial increases in physical activity, but further strategies to maintain physical activity behaviour change are required. Physical activity consultation has demonstrated effective physical activity promotion over periods of up to 2 years in people with type 2 diabetes. Future research should identify the longer term effects of this intervention and the effectiveness of different methods of delivery. Overall, there needs to be a lot more focus on this area of research. Without this, the abundance of research investigating the effects of physical activity on people with insulin resistance and type 2 diabetes is essentially redundant.
A lifestyle intervention of weight-gain restriction: diet and exercise in obese women with gestational diabetes mellitus
Authors: Artal Raul , Catanzaro Rosemary B. , Gavard Jeffrey A. , Mostello Dorothea J. , Friganza Joann C.
Published: May 2007

Objective: This study assessed whether a weight-gain restriction regimen, with or without exercise, would impact glycemic control, pregnancy outcome, and total pregnancy weight gain in obese subjects with gestational diabetes mellitus (GDM). A total of 96 subjects with GDM met the inclusion criteria and were sequentially recruited, with 39 subjects self-enrolled in the exercise and diet (ED) group, and the remaining 57 subjects self-enrolled in the diet (D) group owing to contraindications or a lack of personal preference to exercise. All patients were provided a eucaloric or hypocaloric consistent carbohydrate meal plan and instructed in the self-monitoring of blood glucose. In addition, all ED subjects were prescribed an exercise routine equivalent to a 60% symptom-limited VO2max. Subjects were followed at weekly or biweekly office visits. Results showed maternal weight and body mass index (35.2 ± 7.2 (ED) vs. 33.5 ± 9.2 (D)) at study entry as well as number of weeks into the study (7.7 ± 5.7 (ED) vs. 9.4 ± 4.7 (D)) were similar in both the ED and D groups. Weight gain per week was significantly lower in the ED group than in the D group (0.1 ± 0.4 kg vs. 0.3 ± 0.4 kg; p < 0.05). Subjects (either ED or D) who gained weight had a higher percentage of macrosomic infants than those subjects who lost weight or had no weight change during pregnancy. Other pregnancy and fetal outcomes such as complications, gestational age at delivery, and rate of cesarean delivery were similar in both groups. Conclusions of this study were that caloric restriction and exercise result in limited weight gain in obese subjects with GDM, less macrosomic neonates, and no adverse pregnancy outcomes. Pregnancy is an ideal time for behaviour modification, and this intervention may also help promote long-term healthy lifestyle changes.
Type 1 diabetes: exercise and hypoglycemia
Authors: Briscoe Vanessa Jones , Tate Donna Bowman , Davis Stephen Neil
Published: May 2007

The Diabetes Control and Complications Trial demonstrated that tight control of diabetes management greatly reduces the risk of microvascular complications of diabetes. Unfortunately, tight control of blood glucose can also result in hypoglycemia, especially in patients with type 1 diabetes mellitus (T1DM). It is now widely recognized that antecedent hypoglycemia can blunt neuroendocrine, autonomic nervous system (ANS), and metabolic counterregulatory responses to subsequent hypoglycemia. Thus, blunted counterregulatory defenses against falling plasma glucose levels are a major risk factor for hypoglycemia in people with diabetes. This risk is also complicated by a difference in responses between males and females. Because of the qualitative similarity of neuroendocrine, ANS, and metabolic responses to hypoglycemia and exercise, we developed studies to determine whether neuroendocrine and ANS counterregulatory dysfunction play a role in the pathogenesis of exercise-related hypoglycemia in T1DM. Results from these studies have shown that neuroendocrine (catecholamine and glucagon), ANS (muscle sympathetic nerve activity), and metabolic (lipolysis and glucose kinetics) responses are blunted during exercise after antecedent hypoglycemia, and that there is a sexual dimorphism in responses. Similarly, antecedent episodes of exercise can blunt counterregulatory responses during subsequent hypoglycemia, thereby creating reciprocal feed-forward vicious cycles that increase the risk of hypoglycemia during either stress.
Role of Akt substrate of 160 kDa in insulin-stimulated and contraction-stimulated glucose transport
Authors: Cartee Gregory D. , Wojtaszewski Jørgen F.P.
Published: May 2007

Insulin and exercise, the most important physiological stimuli to increase glucose transport in skeletal muscle, trigger a redistribution of GLUT4 glucose transporter proteins from the cell interior to the cell surface, thereby increasing glucose transport capacity. The most distal insulin signaling protein that has been linked to GLUT4 translocation, Akt substrate of 160 kDa (AS160), becomes phosphorylated in insulin-stimulated 3T3-L1 adipocytes; this is im​portant for insulin-stimulated GLUT4 translocation and glucose transport. Insulin also induces a rapid and dose-dependent increase in AS160 phosphorylation in skeletal muscle. Available data from skeletal muscle support the concepts developed in adipocytes with regard to the role AS160 plays in the regulation of insulin-stimulated glucose transport. In vivo exercise, in vitro contractions, or in situ contractions can also stimulate AS160 phosphorylation. AMP-activated protein kinase (AMPK) is likely important for phosphorylating AS160 in response to exercise/contractile activity, whereas Akt2 appears to be important for insulin-stimulated AS160 phosphorylation in muscle. Evidence of a role for AS160 in exercise/contraction-stimulated glucose uptake is currently inconclusive. The distinct signaling pathways that are stimulated by insulin and exercise/contraction converge at AS160. Although AS160 phosphorylation is apparently important for insulin-stimulated GLUT4 translocation and glucose transport, it is uncertain whether elevated AS160 phosphorylation plays a similar role with exercise/contraction.
Exercise, pregnancy, and insulin sensitivity – what is new?
Authors: Damm Peter , Breitowicz Bettina , Hegaard Hanne
Published: May 2007

Pregnancy is characterized by a marked physiological insulin resistance. Overweight and obesity or lack of physical activity can aggravate this reduced insulin sensitivity further. Increased insulin resistance has been associated with serious pregnancy complications, such as gestational diabetes mellitus (GDM) and pre-eclampsia. Recent studies clearly indicate that physical activity before and during pregnancy can reduce the risk of GDM and pre-eclampsia.
Other adaptations to training/inactivity in type 2 diabetics and other groups with insulin resistance: emphasis on prevention of CHD
Authors: Dela Flemming
Published: May 2007

Physical training is recommended for the prevention and treatment of cardiovascular disease in the general population. In patients with type 2 diabetes this is even more important, because the risk of clinical atherosclerotic disease is 2- to 3-fold that of nondiabetics and the survival rate is poorer. However, increased daily physical activity (e.g., walking for exercise) has been shown to reduce the risk of premature death from all causes and from cardiovascular disease in particular. The mechanism for the positive effect of physical training may be a reduction of known risk factors for atherosclerosis, but a direct effect on the atherosclerotic process per se cannot be excluded.
Responses to acute exercise in type 2 diabetes, with an emphasis on metabolism and interaction with oral hypoglycemic agents and food intake
Authors: Galbo Henrik , Tobin Lillan , van Loon Luc J.C.
Published: May 2007

In people with type 1 diabetes mellitis (DM), insulin administration, food intake, and exercise have to be carefully matched to avoid either hypo- or hyperglycemia. People with type 2 DM have some insulin secretion, which changes with needs. Accordingly, during exercise, these people do not run the same metabolic risks as people with type 1 DM. However, a contraction-mediated increase in glucose clearance in muscle is intact in type 2 DM. Therefore, , in the postabsorptive state in diet-treated type 2 DM, a marked reduction in hyperglycemia can occur during prolonged moderate exercise. Sulfonylurea drugs augment the rate of decline in plasma glucose, because stimulation of insulin secretion reduces hepatic glucose production. After abstention from sulfonylurea for 5 days, the rate of decrease in plasma glucose with exercise is also enhanced, but from a higher glucose level. In the postabsorptive state, brief vigourous exercise elicits an increase in plasma glucose concentration, reflecting an exaggerated counterregulatory hormone response and glucose production. Moreover, insulin sensitivity is reduced in the early postexercise period. In the postprandial state, both prolonged moderate exercise and intermittent high-intensity exercise markedly decrease meal-induced increases in glucose, insulin, and C-peptide concentrations, whereas glucose appearance in plasma is unchanged. When exercise bouts are isocaloric, responses are identical, indicating that overall energy expenditure, and not peak exercise intensity, is the major determinant of exercise-induced changes in overall glucose homeostasis and insulin secretion in type 2 DM. Neither prolonged moderate nor intermittent high-intensity exercise performed in the postprandial state influences glucose or insulin responses to a subsequent meal. Finally, in people with type 2 DM, after a high-fat meal, prolonged moderate exercise reduces the exaggerated increases in plasma concentrations of triglycerides contained in chylomicrons and very low-density lipoproteins.
Physical activity and diabetes: current considerations
Authors: Schrauwen Patrick
Published: May 2007

The prevalence of diabetes is increasing rapidly. Overeating, leading to obesity and overweight, is often considered the main determinant of this increase. However, evidence is accumulating that physical inactivity may be as important a factor in the development of diabetes as being overweight. The reviews in this issue of Applied Physiology, Nutrition, and Metabolism discuss the current knowledge on the role of physical activity in the prevention and treatment of diabetes.
Lipid mediators in membrane rafts are important determinants of human health and disease
Authors: Ma David W.L.
Published: May 2007

The new field of membrane rafts has provided fresh insight and a novel framework in which to understand the interaction, relation, and organization of lipids and proteins within cell membranes. This review will examine our current understanding of membrane rafts and their role in human health. In addition, the effect of various lipids, including dietary lipids, on membrane raft structure and function will be discussed. Membrane rafts are found in all cells and are characterized by their high concentration of cholesterol, sphingolipids, and saturated fatty acids. These lipids impart lateral segregation of membrane proteins, thus facilitating the spatial organization and regulation of membrane proteins involved in many cellular processes, such as cell proliferation, apoptosis, and cell signaling. Therefore, membrane rafts are shedding new light on the origins of metabolic disturbances and diseases such as cancer, insulin resistance, inflammation, cardiovascular disease, and Alzheimer’s disease, which will be further discussed in this review.
EXACT RESULTS FOR THE ONE-DIMENSIONAL MANY-BODY PROBLEM WITH CONTACT INTERACTION: INCLUDING A TUNABLE IMPURITY
Authors: CAUDRELIER V. , CRAMPÉ N.
Published: May 2007

The one-dimensional problem of N particles with contact interaction in the presence of a tunable transmitting and reflecting impurity is investigated along the lines of the coordinate Bethe ansatz. As a result, the system is shown to be exactly solvable by determining the eigenfunctions and the energy spectrum. The latter is given by the solutions of the Bethe ansatz equations which we establish for different boundary conditions in the presence of the impurity. These impurity Bethe equations contain as special cases well-known Bethe equations for systems on the half-line. We briefly study them on their own through the toy-examples of one and two particles. It turns out that the impurity can be tuned to lift degeneracies in the energies and can create bound states when it is sufficiently attractive. The example of an impurity sitting at the center of a box and breaking parity invariance shows that such an impurity can be used to confine a stationary state asymmetrically. This could have interesting applications in condensed matter physics.
NUMERICAL STUDY ON THE INFLUENCE OF SURFACE ROUGHNESS ON FLUID FLOW AND MASS TRANSFER IN A FLAT-PLATE MICROCHANNEL BIOREACTOR
Authors: ZENG YAN , LEE THONG-SEE , YU PENG , LOW HONG-TONG
Published: May 2007

Surface roughness exists in most microfluidic devices due to the microfabrication technique or particle adhesion. The present study has developed a numerical model based on Finite Volume Method to simulate the fluid flow and mass transfer in a flat-plate microchannel bioreactor with an array of rough elements uniformly placed on the bottom wall. Both semicircle and triangle roughness are considered to include more shapes of roughness elements. A monolayer of cells is assumed to attach to the base of the channels and consumes species from culture medium. The results show that the roughness size ratio (α) and the roughness distribution ratio (β) have direct and significant effects on fluid flow and mass transfer. The dimensionless parameters Peclet number (Pe) and Damkohler number (Da) can also influence mass transfer greatly. Although the two types of roughness have similar effects, at the same condition, the triangle roughness has larger effect on shear stress by showing higher dimensionless values at the channel base; the semicircle roughness has larger effect on mass transfer by showing lower dimensionless minimum base concentration [Formula: see text] and higher dimensionless absorption rate (Δj%). However, it is important to ensure the lower maximum shear stress and the adequate minimum species concentration for cell growth in rough channels. Hence, if the maximum shear stress and minimum concentration in rough channels can satisfy the critical conditions for cell growth, rough channels would be better than smooth channels because of their lower shear stress at the flat-bed part and higher mass transfer efficiency. The results would provide guidance on the flow and perfusion requirements to avoid shear stress damage and solute depletion or toxicity during cell culture.
EVIDENCE FOR A QUARK-GLUON PLASMA AT RHIC
Authors: HARRIS JOHN W.
Published: May 2007

This presentation is given in honor of Walter Greiner's 70th birthday, in recognition of the pioneering work of his "Frankfurt School" and their contributions to the field of heavy ion physics. Ultra-relativistic collisions of heavy nuclei at the Relativistic Heavy Ion Collider (RHIC) form an extremely hot system at energy densities greater than 5 GeV/fm3, where normal hadrons cannot exist. Upon rapid cooling of the system to a temperature T ~ 175 MeV and vanishingly small baryo-chemical potential, hadrons coalesce from quarks at the quark-hadron phase boundary predicted by lattice QCD. A large amount of collective (elliptic) flow at the quark level provides evidence for strong pressure gradients in the initial partonic stage of the collision when the system is dense and highly interacting prior to coalescence into hadrons. The suppression of both light (u,d,s) and heavy (c,b) hadrons at large transverse momenta, that form from fragmentation of hard-scattered partons, and the quenching of di-jets provide evidence for extremely large energy loss of partons as they attempt to propagate through the dense, strongly-coupled, colored medium created at RHIC.
THE ROLE OF COLLECTIVE FLOW IN HEAVY ION COLLISIONS
Authors: RITTER HANS GEORG
Published: May 2007

The motivation for flow measurements and the actual measurements at different energy domains are reviewed. At energies around 1 AGeV flow measurements have yielded information about the equation of state of nuclear matter. At RHIC energies partonic collectivity has been established.
EQUILIBRATION OF MATTER IN RELATIVISTIC HEAVY-ION COLLISIONS
Authors: BRAVINA L. , ARSENE I. , NILSSON M. S. , TYWONIUK K. , ZABRODIN E. , BLEICHER M. , STÖCKER H. , GREINER W.
Published: May 2007

The chemical and thermal equilibration in the central zone of heavy-ion collisions at energies from AGS to SPS is studied within the microscopic transport model. Yields and energy spectra obtained for the central cell in the reaction are compared to the predictions of the thermal statistical model. It is found that kinetic, thermal, and chemical equilibration of the expanding hadronic matter are nearly approached for the period of 10-18 fm/c. Within this time the matter in the cell expands almost isentropically. For the bombarding energies around 40 AGeV the system crosses the critical point in the T - μB plane predicted by lattice QCD calculations. The net strangeness in the central cell is negative (though small). The characteristic kink in the T - μB diagrams corresponding to beginning of the equilibrated phase is observed for all energies. The origin of this phenomenon deserves further investigation.
FROM TRAPPED ATOMS TO LIBERATED QUARKS
Authors: SCHÄFER THOMAS
Published: May 2007

We discuss some aspects of cold atomic gases in the unitarity limit that are of interest in connection with the physics of dense hadronic matter. We consider, in particular, the equation of state at zero temperature, the magnitude of the pairing gap, and the phase diagram at non-zero polarization.