bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-invasive measurement of the response of right ventricular pressure to exercise, and its relation to aerobic capacity
Authors: Möller Thomas , Peersen Kari , Pettersen Eirik , Thaulow Erik , Holmstrøm Henrik , Fredriksen Per Morten
Published: August 2009

Introduction

Exercise echocardiography assesses exercise-induced pulmonary hypertension. The upper normal limit of right ventricular systolic pressure during exercise is not well established. Our study aims to investigate the response of right ventricular systolic pressure in relation to aerobic capacity.

Methods and results

Cardiopulmonary exercise testing using a treadmill, and echocardiography during supine cycling, were performed in 113 healthy volunteers aged 13 to 25 years. Maximal right ventricular systolic pressure during evaluable exercise studies obtained in 108 subjects showed a Gaussian distribution only after separating the endurance trained subjects, specifically 12 athletes with Z-score of peak oxygen uptake higher than 2.0, from the normally trained group of 97 subjects. Maximal right ventricular systolic pressure during exercise in the normally trained group showed a mean of 38.0 millimetres of mercury, with standard deviation of 7.2, a median value of 39.0, and a range from 17 to 63, and the 95th percentile was 51 millimetres of mercury. In the athletes, the maximal right ventricular systolic pressure was higher, with a median of 55.5, a range from 28 to 69, this being significant, with p equal to 0.004). Of the 12 athletes, 8 (67%) showed a response of right ventricular systolic pressure to exercise exceeding 50 millimetres of mercury, but only 8 of 97 normally trained subjects (8%) showed a similar response, this also being significant, with p less than 0.001.

Conclusions

Our study confirms the great variability in the response of right ventricular systolic pressure to exercise in healthy individuals, with 50 millimetres of mercury representing the upper normal limit. Endurance-trained athletes show higher levels, and two-thirds have abnormal responses exceeding 50 millimetres of mercury.
Molecular neurodevelopment: Anin vivo31P-1H MRSI study
Authors: GOLDSTEIN GERALD , PANCHALINGAM KANAGASABAI , MCCLURE RICHARD J. , STANLEY JEFFREY A. , CALHOUN VINCE D. , PEARLSON GODFREY D. , PETTEGREW JAY W.
Published: August 2009

Synaptic development and elimination are normal neurodevelopmental processes, which if altered could contribute to various neuropsychiatric disorders.31P-1H magnetic resonance spectroscopic imaging (MRSI) and structural magnetic resonance imaging (MRI) exams were conducted on 105 healthy children ages 6–18 years old to identify neuromolecular indices of synaptic development and elimination. Over the age range studied, age-related changes in high-energy phosphate (phosphocreatine), membrane phospholipid metabolism (precursors and breakdown products), and percent gray matter volume were found. These neuromolecular and structural indices of synaptic development and elimination are associated with development of several cognitive domains. Monitoring of these molecular markers is essential for devising treatment strategies for neurodevelopmental disorders. (JINS, 2009,15, 671–683.)
Homo Politicusand Argument (Nearly) All the Way Down: Persuasion in Politics
Authors: Crawford Neta C.
Published: August 2009

Much theorizing about world politics and many policy recommendations are predicated on a rather thin view ofhomo politicus,often assuming that humans are rational and self-interested strategic actors and that force is theultima ratioof politics. This thin notion should be replaced by a richer understanding ofhomo politicusthat includes the characteristic activities of political actors: we fight, we feel, we talk, and we build institutions. This understanding helps illuminate the scope and limits of strategic action, argument and persuasion in world politics in both empirical and normative senses. I describe the spectrum of political action that situates the role of argument and persuasion within the extremes of brute force on one side and mutual communication on the other. I also discuss barriers to argument and communication. Noting the role of argument in this spectrum of international and domestic political practice suggests that it is argument (nearly) all the way down and that the scope of argument can be and in some cases has increased over thelongue durée.Coercion, by itself, has a limited role in world politics. The claim that there are distinctive logics of argumentation, strategic action, or appropriateness misses the point. Argument is the glue of politics—its characteristic practice. Understanding politics as argumentation has radical empirical and normative implications for the study and practice of politics.
Differential expression of connexins in trigeminal ganglion neurons and satellite glial cells in response to chronic or acute joint inflammation
Authors: Garrett Filip G. , Durham Paul L.
Published: August 2009

Trigeminal nerve activation in response to inflammatory stimuli has been shown to increase neuron–glia communication via gap junctions in trigeminal ganglion. The goal of this study was to identify changes in the expression of gap junction proteins, connexins (Cxs), in trigeminal ganglia in response to acute or chronic joint inflammation. Although mRNA for Cxs 26, 36, 40 and 43 was detected under basal conditions, protein expression of only Cxs 26, 36 and 40 increased following capsaicin or complete Freund's adjuvant (CFA) injection into the temporomandibular joint (TMJ). While Cx26 plaque formation between neurons and satellite glia was transiently increased following capsaicin injections, Cx26 plaque formation between neurons and satellite glia was sustained in response to CFA. Interestingly, levels of Cx36 and Cx40 were only elevated in neurons following capsaicin or CFA injections, but the temporal response was similar to that observed for Cx26. In contrast, Cx43 expression was not increased in neurons or satellite glial cells in response to CFA or capsaicin. Thus, trigeminal ganglion neurons and satellite glia can differentially regulate Cx expression in response to the type and duration of inflammatory stimuli, which likely facilitates increased neuron–glia communication during acute and chronic inflammation and pain in the TMJ.
Modulation of synaptic transmission and plasticity by cell adhesion and repulsion molecules
Authors: Dityatev Alexander , Bukalo Olena , Schachner Melitta
Published: August 2009

Adhesive and repellent molecular cues guide migrating cells and growing neurites during development. They also contribute to synaptic function, learning and memory in adulthood. Here, we review the roles of cell adhesion molecules of the immunoglobulin superfamily (Ig-CAMs) and semaphorins (some of which also contain Ig-like domains) in regulation of synaptic transmission and plasticity. Interestingly, among the seven studied Ig-CAMs, the neuronal cell adhesion molecule proved to be important for all tested forms of hippocampal plasticity, while its associated unusual glycan polysialic acid is necessary and sufficient part for synaptic plasticity only at CA3-CA1 synapses. In contrast, Thy-1 and L1 specifically regulate long-term potentiation (LTP) at synapses formed by entorhinal axons in the dentate gyrus and cornu ammonis, respectively. Contactin-1 is important for long-term depression but not for LTP at CA3-CA1 synapses. Analysis of CHL1-deficient mice illustrates that at intermediate stages of development a deficit in a cell adhesion molecule is compensated but appears as impaired LTP during early and late postnatal development. The emerging mechanisms by which adhesive Ig-CAMs contribute to synaptic plasticity involve regulation of activities of NMDA receptors and L-type Ca2+channels, signaling via mitogen-activated protein kinase p38, changes in GABAergic inhibition and motility of synaptic elements. Regarding repellent molecules, available data for semaphorins demonstrate their activity-dependent regulation in normal and pathological conditions, synaptic localization of their receptors and their potential to elevate or inhibit synaptic transmission either directly or indirectly.
Uncoupling of astrogliosis from epileptogenesis in adenosine kinase (ADK) transgenic mice
Authors: Li Tianfu , Lan Jing-Quan , Boison Detlev
Published: August 2009

The astrocytic enzyme adenosine kinase (ADK) is a key negative regulator of the brain’s endogenous anticonvulsant adenosine. Astrogliosis with concomitant upregulation of ADK is part of the epileptogenic cascade and contributes to seizure generation. To molecularly dissect the respective roles of astrogliosis and ADK-expression for seizure generation, we used a transgenic approach to uncouple ADK-expression from astrogliosis: in Adk-tg mice the endogenous Adk-gene was deleted and replaced by a ubiquitously expressed Adk-transgene with novel ectopic expression in pyramidal neurons, resulting in spontaneous seizures. Here, we followed a unique approach to selectively injure the CA3 of these Adk-tg mice. Using this strategy, we had the opportunity to study astrogliosis and epileptogenesis in the absence of the endogenous astrocytic Adk-gene. After triggering epileptogenesis we demonstrate astrogliosis without upregulation of ADK, but lack of seizures, whereas matching wild-type animals developed astrogliosis with upregulation of ADK and spontaneous recurrent seizures. By uncoupling ADK-expression from astrogliosis, we demonstrate that global expression levels of ADK rather than astrogliosis per se contribute to seizure generation.
Electrical signalling properties of oligodendrocyte precursor cells
Authors: Bakiri Yamina , Attwell David , Káradóttir Ragnhildur
Published: August 2009

Oligodendrocyte precursor cells (OPCs) have become the focus of intense research, not only because they generate myelin-forming oligodendrocytes in the normal CNS, but because they may be suitable for transplantation to treat disorders in which myelin does not form or is damaged, and because they have stem-cell-like properties in that they can generate astrocytes and neurons as well as oligodendrocytes. In this article we review the electrical signalling properties of OPCs, including the synaptic inputs they receive and their use of voltage-gated channels to generate action potentials, and we describe experiments attempting to detect output signalling from OPCs. We discuss controversy over the existence of different classes of OPC with different electrical signalling properties, and speculate on the lineage relationship and myelination potential of these different classes of OPC. Finally, we point out that, since OPCs are the main proliferating cell type in the mature brain, the discovery that they can develop into neurons raises the question of whether more neurons are generated in the mature brain from the classical sites of neurogenesis in the subventricular zone of the lateral ventricle and the hippocampal dentate gyrus or from the far more widely distributed OPCs.
Nitrogen fixation in the western equatorial Pacific: Rates, diazotrophic cyanobacterial size class distribution, and biogeochemical significance
Authors: Bonnet Sophie , Biegala Isabelle C. , Dutrieux Pierre , Slemons Lia O. , Capone Douglas G.
Published: August 2009

A combination of 15N2 labeling, Tyramide Signal Amplification–Fluorescent in Situ Hybridization (TSA‐FISH) assay, and chemical analyses were performed along a trophic gradient (8000 km) in the equatorial Pacific. Nitrogen fixation rates were low (0.06 ± 0.02 to 2.8 ± 2.1 nmol L−1 d−1) in HNLC waters, higher in the warm pool (0.11 ± 0.0 to 18.2 ± 2.8 nmol L−1 d−1), and extremely high close to Papua New Guinea (38 ± 9 to 610 ± 46 nmol L−1 d−1). Rates attributed to the <10‐μm fraction accounted for 74% of total activity. Both unicellular and filamentous diazotrophs were detected and reached 17 cells mL−1 and 1.85 trichome mL−1. Unicellular diazotrophs were found to be free‐living in <10‐μm fraction or in association with mucilage, particles, or eukaryotes in the >10‐μm fraction, leading to a possible overestimation of this fraction to total N2 fixation. In oceanic waters, 98% of the unicellular diazotrophs were picoplanktonic. Finally, we found a clear longitudinal pattern of niche partitioning between diazotroph groups: while unicellular diazotrophs were present all along the transect, Trichodesmium spp. were detected only in coastal waters, where nitrogen fixation associated to both size fractions was greatly stimulated.
F region behavior in the SED plume during a geomagnetic superstorm: A case study
Authors: Yuan Zhi‐Gang , Deng Xiao‐Hua , Zhang Shun‐Rong , Wan Wei‐Xing , Reinisch Bodo W.
Published: August 2009

We report observations from the GPS total electron content (TEC), ionosonde, and Millstone Hill incoherent scatter radar showing some interesting features of the height profile of the ionospheric electron density that occurred during a passage of a storm‐enhanced density (SED) plume during the geomagnetic superstorm on 20 November 2003. First, the TEC increases to about 6.58 times the quiet day value, while the F peak plasma density (NmF2) only enhances by a factor of 1.37. Second, the F2 layer peak height (hmF2) is dramatically lifted from the quiet time altitude of 250 km to an unusual altitude of 577 km. Furthermore, the topside Chapman scale height HT is larger by a factor of 6.25 compared to the quiet time value. As a result, the electron density content with an α‐Chapman function above 700 km contributes about 59% to the total content during the SED event. Our analysis shows that during a passage of the SED plume, the enhancement of TEC is mainly attributed to the great increase of HT with a very high hmF2.
Thermospheric density model blending techniques: Bridging the gap between satellites and sounding rockets
Authors: Kim Jung Soo , Spencer David B. , Kane Timothy J. , Urbina Julio
Published: August 2009

Uncertainty in the atmospheric density is a crucial error source in calculating orbits of satellites in low Earth orbit. As a result, establishing accurate thermospheric neutral density models is important for predicting the motion of these satellites. Unfortunately, since density data in the altitude range between 140 and 200 km are sparse, predicting the neutral density to estimate atmospheric drag effects on the motion of satellites operating in this altitude region is subject to relatively large errors. A previous study found that the Jacchia‐Bowman model (JB2006) is the most reliable thermospheric empirical neutral density model above 200 km and the Naval Research Laboratory's Mass Spectrometer Incoherent Scatter (NRLMSISE‐00) model, whose core formulation is based on incoherent scatter radar data, can be considered a more reliable neutral density model below approximately 140 km. We have developed a simple bridging technique to blend the two models between these two regions. A two‐body model with atmospheric drag was used to compare effects of various atmospheric density models. These preliminary tests are conducted by propagating the positions of satellites orbiting between 140 and 200 km, with various ballistic coefficients, using the JB2006, the NRLMSISE‐00, and the bridging technique.
Mixing and phase partitioning of primary and secondary organic aerosols
Authors: Asa‐Awuku A. , Miracolo M. A. , Kroll J. H. , Robinson A. L. , Donahue N. M.
Published: August 2009

Predicting primary and secondary organic aerosol (POA and SOA) concentrations requires understanding the phase partitioning of semi‐volatile organic species. A well‐mixed single phase organic aerosol can absorb greater amounts of semi‐volatile species but little experimental evidence exists on the phase distribution of particulate organics. We investigated the phase partitioning and mixing of semi‐volatile POA and SOA in a smog chamber. Particle time of flight (PToF) data from an Aerodyne aerosol mass spectrometer (AMS) were used to quantify the extent of mixing. The SOA plus motor oil and diesel fuel combination produced a weakly mixed system, in which two particulate organic phases coexist. However, the POA in diesel exhaust readily mixed with SOA, forming a single phase after one hour. Although both POA types contain semi‐volatile components, there is a fundamental difference in their partitioning behavior with SOA. The high resolution AMS data reveal minor differences in composition between the two types of POA. This work provides further evidence that there exists a set of unidentified components that influence particulate mixing that affect OA formation and suggests the extent of absorbent phase mixing (strong versus weak) can be observed and quantified with PToF data.
Temporal and spatial evolution of the solar energetic particle event on 20 January 2005 and resulting radiation doses in aviation
Authors: Matthiä D. , Heber B. , Reitz G. , Meier M. , Sihver L. , Berger T. , Herbst K.
Published: August 2009

The solar energetic particle event on 20 January 2005 was one of the largest ground level events ever observed. Neutron monitor stations in the Antarctic recorded count rate increases of several thousand percent caused by secondary energetic particles, and it took more than 36 h to return to background level. Such huge increases in high energetic solar cosmic radiation on the ground are obviously accompanied by considerable changes in the radiation environment at aviation altitudes. Measurements of 28 neutron monitor stations were used in this work to numerically approximate the primary solar proton spectra during the first 12 h of the event by minimizing the differences between measurements and the results of Monte‐Carlo calculated count rate increases. The primary spectrum of solar energetic protons was approximated by a power law in rigidity and a linear angular distribution. The incoming direction of the solar energetic particles was determined and compared to the interplanetary magnetic field direction during the event. The effects on the radiation exposure at altitudes of about 12 km during that time were estimated to range from none at low latitudes up to almost 2 mSv/h for a very short time in the Antarctic region and about 0.1 mSv/h at high latitudes on the Northern Hemisphere. After 12 h, dose rates were still increased by 50% at latitudes above 60° whereas no increases at all occurred at latitudes below 40° during the whole event.
Reverse convection potential saturation during northward IMF under various driving conditions
Authors: Wilder F. D. , Clauer C. R. , Baker J. B. H.
Published: August 2009

We report the results of an investigation of the reverse convection potentials in the dayside high‐latitude ionosphere during periods of steady northward interplanetary magnetic field (IMF). While it has been demonstrated that the reverse convection potentials exhibit saturation behavior, an investigation into how the saturated reverse convection cells respond to various driving conditions has not yet been performed. We use the OMNI database from 1998 to 2007 to search for events in solar wind data propagated to the bow shock when the IMF is northward and when various driving parameters are stable for more than 40 min. We then use bin‐averaged SuperDARN Doppler radar velocity data to apply a spherical harmonic fit to calculate the average potential pattern for various driving conditions. Results show that the saturated reverse convection potential during northward IMF is substantially lower than during southward IMF (as expected), but the strength of the saturation electric field at a particular location is comparable during northward IMF to what it is during southward IMF. Seasonal dependence and dependence on the Alfvènic Mach number and solar wind β are also investigated. It appears that the reverse convection potential demonstrates the opposite of what is expected for seasonal dependence, and that the Alfvènic Mach number is not the fundamental driver of its saturation.
Effects of Doubling the Portion Size of Fruit and Vegetable Side Dishes on Children's Intake at a Meal
Authors: Kral Tanja V.E. , Kabay April C. , Roe Liane S. , Rolls Barbara J.
Published: August 2009

Increasing the portion size of energy‐dense entrées has been shown to increase children's energy intake during a meal. It remains to be investigated whether serving larger portions to children can be used to promote intake of more healthful foods, such as fruits and vegetables (F&V). The aim of the present study was to examine the effects of increasing the portion size of F&V side dishes on children's intake. Forty‐three children (22 boys, 21 girls), aged 5–6 years, were served dinner once a week for 2 weeks. Each dinner consisted of pasta with tomato sauce, three F&V side dishes (broccoli, carrots, and applesauce), and milk. The portion size of the F&V was doubled between experimental conditions whereas the size of the pasta remained constant. Doubling the portion size of the side dishes resulted in a 43% increase in children's intake of the fruit side dish (P = 0.001), but did not affect children's intake of the two vegetable side dishes (P > 0.60). Further, when the portion size of F&V side dishes was doubled, children ate significantly less of the pasta (P = 0.04). The difference in meal energy intake between portion size conditions (19.5 ± 16.3 kcal) was not significant (P = 0.24). Although more studies are needed to understand whether increases in portion size can influence vegetable intake, children did eat more in response to a large quantity of a preferred low energy‐dense fruit side dish at meals. Thus variations in portion size can be used strategically to help children achieve the recommended intake of fruits.
Increased Expression of DNA Methyltransferase 3a in Obese Adipose Tissue: Studies With Transgenic Mice
Authors: Kamei Yasutomi , Suganami Takayoshi , Ehara Tatsuya , Kanai Sayaka , Hayashi Koji , Yamamoto Yuji , Miura Shinji , Ezaki Osamu , Okano Masaki , Ogawa Yoshihiro
Published: August 2009

Epigenetic mechanisms are likely to be involved in the development of obesity. This study was designed to examine the role of a DNA methyltransferase (Dnmt3a), in obese adipose tissue. The gene expression of Dnmts was examined by quantitative real‐time PCR analysis. Transgenic mice overexpressing Dnmt3a in the adipose tissue driven by the aP2 promoter were created (Dnmt3a mice). DNA methylation of downregulated genes was examined using bisulfite DNA methylation analysis. Dnmt3a mice were fed a methyl‐supplemented or high‐fat diet, and subjected to body weight measurement and gene expression analysis of the adipose tissue. Expression of Dnmt3a was markedly upregulated in the adipose tissue of obese mice. The complementary DNA (cDNA) microarray analysis of Dnmt3a mice revealed a slight decrease in the gene expression of secreted frizzled‐related protein 1 (SFRP1) and marked increase in that of interferon responsive factor 9 (IRF9). In the SFRP1 promoter, DNA methylation was not markedly increased in Dnmt3a mice relative to wild‐type mice. In experiments with a high‐fat diet or methyl‐supplemented diet, body weight did not differ significantly with the genotypes. Gene expression levels of inflammatory cytokines such as tumor necrosis factor‐α (TNF‐α) and monocyte chemoattractant protein‐1 (MCP‐1) were higher in Dnmt3a mice than in wild‐type mice on a high‐fat diet. This study suggests that increased expression of Dnmt3a in the adipose tissue may contribute to obesity‐related inflammation. The data highlight the potential role of Dnmt3a in the adult tissue as well as in the developing embryo and cancer.
Treatment of Obese Adolescents: The Influence of Periodization Models and ACE Genotype
Authors: Foschini Denis , Araújo Ronaldo C. , Bacurau Reury F.P. , De Piano Aline , De Almeida Sandro S. , Carnier June , Rosa Thiago D.S. , De Mello Marco T. , Tufik Sérgio , Dâmaso Ana R.
Published: August 2009

The aims of the present study were to compare the effects of two periodization models on metabolic syndrome risk factors in obese adolescents and verify whether the angiotensin‐converting enzyme (ACE) genotype is important in establishing these effects. A total of 32 postpuberty obese adolescents were submitted to aerobic training (AT) and resistance training (RT) for 14 weeks. The subjects were divided into linear periodization (LP, n = 16) or daily undulating periodization (DUP, n = 16). Body composition, visceral and subcutaneous fat, glycemia, insulinemia, homeostasis model assessment of insulin resistance (HOMA‐IR), lipid profiles, blood pressure, maximal oxygen consumption (VO2max), resting metabolic rate (RMR), muscular endurance were analyzed at baseline and after intervention. Both groups demonstrated a significant reduction in body mass, BMI, body fat, visceral and subcutaneous fat, total and low‐density lipoprotein cholesterol, blood pressure and an increase in fat‐free mass, VO2max, and muscular endurance. However, only DUP promoted a reduction in insulin concentrations and HOMA‐IR. It is important to emphasize that there was no statics difference between LP and DUP groups; however, it appears that there may be bigger changes in the DUP than LP group in some of the metabolic syndrome risk factors in obese adolescents with regard to the effect size (ES). Both periodization models presented a large effect on muscular endurance. Despite the limitation of sample size, our results suggested that the ACE genotype may influence the functional and metabolic characteristics of obese adolescents and may be considered in the future strategies for massive obesity control.
Associations of Free Fatty Acids With Insulin Secretion and Action Among African‐American and European‐American Girls and Women
Authors: Goree Laura Lee T. , Darnell Betty E. , Oster Robert A. , Brown Marian A. , Gower Barbara A.
Published: August 2009

Ethnic differences in insulin secretion and action between African Americans (AAs) and European Americans (EAs) may influence mobilization of free fatty acids (FFAs). We tested the hypotheses that FFA concentrations would be associated with measures of insulin secretion and action before and during a glucose challenge test. Subjects were 48 prepubertal girls, 60 premenopausal women, and 46 postmenopausal women. Fasting insulin (insulin0), the acute insulin response to glucose (AIRg), the insulin sensitivity index (SI), basal and nadir FFA (FFA0, FFAnadir), and nadir time (TIMEnadir) were determined during an intravenous glucose tolerance test (IVGTT). Stepwise multiple linear regression (MLR) analysis was conducted to identify associations of FFA0, FFAnadir, and TIMEnadir with ethnicity, age group, insulin measures, indexes of body composition from dual‐energy X‐ray absorptiometry, and measures of fat distribution from computed tomography scan. In this population, insulin0 and AIRg were higher among AAs vs. EAs, whereas SI was lower, independent of age group. MLR analyses indicated that FFA0 was best predicted by lean tissue mass (LTM), leg fat mass, ethnicity (lower in AAs), SI, and insulin0. FFAnadir was best predicted by FFA0, age group, and intra‐abdominal adipose tissue (IAAT). TIMEnadir was best predicted by leg fat mass, AIRg, and SI. In conclusion, indexes of insulin secretion and action were associated with FFA dynamics in healthy girls and women. Lower FFA0 among AAs was independent of insulin0 and SI. Whether lower FFA0 is associated with substrate oxidation or risk for obesity remains to be determined.
Association of Long‐term Change in Waist Circumference With Insulin Resistance
Authors: Park Kyong , Lee Duk‐Hee , Erickson Darin J. , Himes John H. , Shikany James M. , Jacobs David R.
Published: August 2009

Recent studies have shown that fat accumulation is associated with insulin resistance; however, the risks associated with long‐term changes and fluctuations in central fatness are less clear. This study examined the longitudinal relationship between waist circumference (WC) and insulin resistance using three dimensions of WC: baseline WC, slope of linear changes in WC, and fluctuation of WC around the slope during 20 years of follow‐up. Anthropometry, insulin resistance (homeostasis model assessment (HOMAIR)), and lifestyle factors were obtained in a population‐based, prospective observational study (Coronary Artery Risk Development in Young Adults (CARDIA)) during 1985–2006, excluding participants who had been diagnosed with diabetes at any examination. After adjusting for socio‐demographic and lifestyle factors, the evolution of HOMAIR from CARDIA year 15 to 20 was 6.9% higher per standard deviation of year 0 WC (P trend <0.0001) and 6.3% higher per standard deviation increase in the change in WC over the long term (P trend <0.0001). However, WC fluctuations around the linear change were not associated with insulin resistance or its evolution. The level of HOMAIR increased substantially with steeper linear WC slope among initially thinner participants at baseline, whereas this association tended to be weaker in those with higher initial WC (P interaction <0.0001). We conclude that year 0 WC and long‐term increment in WC are associated with worsening insulin resistance. However, the association of HOMAIR with slope of WC change may vary across the range of initial WC.
Individual and Aggregate Years‐of‐life‐lost Associated With Overweight and Obesity
Authors: Finkelstein Eric A. , Brown Derek S. , Wrage Lisa A. , Allaire Benjamin T. , Hoerger Thomas J.
Published: August 2009

This study presents nationally representative estimates of individual and aggregate years‐of‐life‐lost (YLLs) associated with overweight and three categories of obesity separately by age, race, smoking status, and gender strata. Using proportional hazards analysis and data from the National Health Interview Survey (NHIS) Linked Mortality Files, we estimated life expectancies for each BMI strata and quantified YLLs by comparing differences between each strata and the normal BMI reference group. Our results provide further evidence that overweight and mild obesity are not associated with a reduction in life expectancy. However, higher BMI categories are associated with lower expected survival. In aggregate, excess BMI is responsible for ∼95 million YLLs. White females account for more than two‐thirds of the aggregate YLLs. Unless something is done to reduce the rising prevalence of those with BMIs >35, or to mitigate the impact of obesity or its correlates on YLLs, expected life expectancy for US adults may decrease in the future.
Induction of inducible nitric oxide synthase increases the production of reactive oxygen species in RAW264.7 macrophages
Authors: Zhao Kai , Huang Zhen , Lu Hongling , Zhou Juefei , Wei Taotao
Published: August 2009

Macrophages produce a large volume of ROS (reactive oxygen species) through respiratory burst. However, the influence of iNOS [inducible NOS (nitric oxide synthase)] activation on ROS production remains unclear. In the present study, the kinetic generation of ROS in RAW264.7 murine macrophages was monitored by chemiluminescence. PMA induces a robust chemiluminescence in RAW264.7 cells, suggesting PKC (protein kinase C)-related assembly and activation of NOX (NADPH oxidase). The effects of iNOS induction on ROS production were examined. Induction of iNOS expression in RAW264.7 cells with LPS (lipopolysaccharide; 1 μg/ml) causes a significant increase in PMA-induced chemiluminescence, which could be enhanced by the NOS substrate, L-arginine, and could be abolished by the NOS inhibitor, L-NNA (NG-nitro-L-arginine). Further experiments reveal that induction of iNOS expression enhances the PMA-stimulated phosphorylation of the p47phox subunit of NOX, and promotes the relocalization of cytosolic p47phox and p67phox subunits to the membrane. Inhibition of PKCζ by its myristoylated pseudosubstrate significantly decreased the PMA-stimulated phosphorylation of the p47phox in LPS-pretreated cells, suggesting that PKCζ is involved in the iNOS-dependent assembly and activation of NOX. Taken together, the present study suggests that the induction of iNOS upregulates the PMA-induced assembly of NOX and leads to the enhanced production of ROS via a PKCζ-dependent mechanism.
Validation study of the ability of density functionals to predict the planar-to-three-dimensional structural transition in anionic gold clusters
Authors: Mantina Manjeera , Valero Rosendo , Truhlar Donald G.
Published: August 2009

As gold clusters increase in size, the preferred structure changes from planar to three-dimensional and, for anionic clusters, Aun−, the two-dimensional(2D)→three-dimensional (3D) transition is found experimentally to occur between n=11 and n=12. Most density functionals predict that planar structures are preferred up to higher n than is observed experimentally, an exception being the local spin density approximation. Here we test four relatively new functionals for this feature, in particular, M05, M06-L, M06, and SOGGA. We find that M06-L, M06, and SOGGA all predict the 2D→3D transition at the correct value of n. Since the M06-L and M06 functionals have previously been shown to be reasonably accurate for transition metal bond energies, main group atomization energies, barrier heights, and noncovalent interaction energies, and, since they are here shown to perform well for the s-d excitation energy and ionization potential of Au atoms and for the size of Aun− clusters at which the 2D→3D transition occurs, they are recommended for simulating processes catalyzed by gold clusters.
Preparation and photoluminescence of undoped ZnTiO3 thin films
Authors: Ye C. , Wang Y. , Ye Y. , Zhang J. , Li G. H.
Published: August 2009

ZnTiO 3 thin films were prepared by radio frequency cosputtering of ZnO and TiO2. It was found the as-prepared film is amorphous and the cubic phase ZnTiO3 films form after annealing at temperature above 500 °C. The absorption spectra indicate that the optical band gap of the crystalline ZnTiO3 film is about 3.70 eV. A strong photoluminescence band centered at 355 nm consisting of two emission peaks was observed in 800 °C annealed ZnTiO3 thin film, and the peak positions of these two emission move to short wavelength with increasing annealing temperature. It was found the emission peak at ultraviolet zone is resulted from O2− vacancy and that in the blue zone is attributed to Zn2+ vacancy.
Scale dependence and asymptotic very high Reynolds number spectral behavior of multiscale subgrid models
Authors: Cocle R. , Bricteux L. , Winckelmans G.
Published: August 2009

This paper investigates the spectral response of recent multiscale subgrid models, all of eddy viscosity type, in large-eddy simulation (LES) of fully developed turbulence, from moderate to very high Reynolds (Re) number. The objective of this work is to provide useful results about the behavior of the subgrid scale (SGS) models and, in particular, their asymptotic behavior. Such information is indeed important for practitioners using LES to simulate truly high Reynolds number flows. Specifically, we consider LES of homogeneous isotropic turbulence at very high Re and where the LES cutoff (here the grid Δ) is taken well into the inertial range (i.e., Δ/η≥100 with η the Kolmogorov scale). Large LES grids (1283 and 2563) are also used in order to compare and attain the true asymptotic behavior of each SGS model, something not fully observable in LES on smaller grids. An analysis is also carried out to obtain the scale dependence of each model coefficient in the viscous range of turbulence using LES run on several grids and compared to direct numerical simulation. The results provide C for each model and for various Δ/η. A convenient fit then also provides C/C∞ as a function of Δ/η, where C∞ is the asymptotic coefficient. The comparisons are supported using the evolution of resolved energy (global and spectrum), resolved enstrophy, and effective dissipation. It is shown that the multiscale models acting on the high wavenumber part of the LES field are indeed able to provide a significant k−5/3 inertial subrange, yet it is always followed by an energy pileup effect also called “bottleneck.” This effect is also characterized for the various models.
Dielectric and nonlinear electrical behaviors of La-doped CaCu3Ti4O12 ceramics
Authors: Cheng Bo , Lin Yuan-Hua , Yuan Jiancong , Cai Jingnan , Nan Ce-Wen , Xiao Xi , He Jinliang
Published: August 2009

We prepared La doped of CaCu3Ti4O12 ceramics by a solid-state sintering process and observed nonlinear electrical varistor and high dielectric behaviors. Phase composition analyses show that the La can substitute on the Ca sites completely, and have no influence on the phase composition. The impedance spectroscopy at room temperature indicates that the La doping can maintain the dielectric permittivity of CaCu3Ti4O12 (∼104). The relationships between electrical current density versus applied electrical field show that these ceramic samples exhibit nonlinear varistor characteristics, which should be ascribed to the existing potential barrier height at the grain boundary.
Phase transition behaviors of Mo- and nitrogen-doped Ge2Sb2Te5 thin films investigated by in situ electrical measurements
Authors: Huang Yu-Jen , Chen Yen-Chou , Hsieh Tsung-Eong
Published: August 2009

Phase-change behaviors of Ge2Sb2Te5 (GST) thin films doped with molybdenum (Mo) or nitrogen (N) were investigated by utilizing in situ electrical property measurement, x-ray diffraction (XRD), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy. It was found that the Mo doping mainly reduces the resistivity level of amorphous GST while the N-doping raises both the resistivity levels of amorphous and crystalline GSTs. XRD and TEM analyses revealed that the element doping stabilizes the amorphous state of GST and suppresses the grain growth in GST films. This resulted in the increase in recrystallization temperature (Tm) and activation energy (Ea) of amorphous-to-crystalline phase transition in GST layers, as revealed by the calculation in terms of Kissinger’s theory. The results of data fitting into various percolation models and Johnson–Mehl–Avrami analysis indicated the heterogeneous feature of phase transition process in GST layers that the nucleation first occurs at the atmosphere∕sample interface and the recrystallization front advances into the interior of sample in a layer-by-layer manner along the direction of surface normal.
Force induced unfolding of biopolymers in a cellular environment: A model study
Authors: Singh Amit Raj , Giri Debaprasad , Kumar Sanjay
Published: August 2009

Effect of molecular crowding and confinement experienced by protein in the cell during unfolding has been studied by modeling a linear polymer chain on a percolation cluster. It is known that internal structure of the cell changes in time, however, they do not change significantly from their initial structure. In order to model this we introduce the correlation among the different disorder realizations. It was shown that the force-extension behavior for correlated disorder in both constant force ensemble and constant distance ensemble is significantly different than the one obtained in absence of molecular crowding.
Giant magnetic anisotropy changes in Sr2CrReO6 thin films on BaTiO3
Authors: Czeschka F. D. , Geprägs S. , Opel M. , Goennenwein S. T. B. , Gross R.
Published: August 2009

The integration of ferromagnetic and ferroelectric materials into hybrid heterostructures yields multifunctional systems with improved or novel functionality. We here report on the structural, electronic, and magnetic properties of the ferromagnetic double perovskite Sr2CrReO6, grown as epitaxial thin film onto ferroelectric BaTiO3. As a function of temperature, the crystal-structure of BaTiO3 undergoes phase transitions, which induce qualitative changes in the magnetic anisotropy of the ferromagnet. We observe abrupt changes in the coercive field of up to 1.2 T along with resistance changes of up to 6.5%. These results are attributed to the high sensitivity of the double perovskites to mechanical deformation.
Tunable magnetic and transport properties of single crystalline (Co, Ga)-codoped ZnO films
Authors: Lu Zhonglin , Hsu Hua-Shu , Tzeng Yonhua , Zhang Fengming , Du Youwei , Huang Jung-Chun-Andrew
Published: August 2009

A series of metallic (Co, Ga)-codoped ZnO single crystalline films have been grown by molecular beam epitaxy. All of the films exhibit metallic conducting behavior and high free carrier concentrations. Besides room temperature ferromagnetism, the anomalous Hall effect due to spin-orbit interaction was also found. Both the saturation magnetization and anomalous Hall effect can be tuned by the carrier concentration or conductivity, revealing that the ferromagnetism is carrier mediated in (Co, Ga)-codoped ZnO films. Our experimental observations are consistent with the recent theoretical description of carrier mediated magnetism in Co doped ZnO.
Transverse oscillations in a single-layer dusty plasma under microgravity
Authors: Liu Bin , Goree J. , Fortov V. E. , Lipaev A. M. , Molotkov V. I. , Petrov O. F. , Morfill G. E. , Thomas H. M. , Rothermel H. , Ivlev A. V.
Published: August 2009

A single-layer suspension of microparticles was formed in a plasma under microgravity conditions. This single layer is confined at a void boundary by a balance of ion drag and electric forces, where the ion flow velocity is much slower than in the sheath of laboratory plasmas. Using a high-resolution camera that allows measurements of velocities at a low level, the microparticle kinetic temperature was found to be close to that of the neutral gas. The random motion transverse to the single layer was found to have oscillations of the form expected for harmonic oscillators driven by white noise. The driving of the oscillation is mostly attributed to the Brownian motion of neutral atoms, while the damping is mostly due to neutral gas friction. An observed resonance frequency of 25 s−1 allows us to quantify the electric and ion drag forces as being in the range of 0.2–0.4mpg, where mp is the microparticle mass and g is the acceleration of gravity on Earth’s surface. No signature of wave dispersion was detected for this experiment with neon at a pressure of 0.12 Torr.
Biolubricant induced phase inversion and superhydrophobicity in rubber-toughened biopolymer/organoclay nanocomposites
Authors: Bayer Ilker S. , Steele Adam , Martorana Philip , Loth Eric , Robinson Scott J. , Stevenson Darren
Published: August 2009

We present a simple technique to fabricate rubber-toughened biopolymer/organoclay nanocomposite coatings with highly water repellent surface wetting characteristics and strong adhesion to metal surfaces. The technique combines the principles of phase inversion and atomization of multicomponent polymer/organoclay suspensions containing a biolubricant as the nonsolvent. The biolubricant was a blend of cyclomethicone/dimethiconol oil with fruit kernel oils. The ternary system of cellulose nitrate/solvent/biolubricant was blended with rubber dispersed organoclay nanofluids. Natural, synthetic, and fluoroacrylic latex rubbers were used for the purpose. Self-cleaning superhydrophobic coatings were obtained from synthetic and fluoroacrylic rubbers whereas natural rubber containing formulations resulted in sticky superhydrophobic coatings.
Reversible colossal resistance switching in (La,Pr,Ca)MnO3: Cryogenic nonvolatile memories
Authors: Yi H. T. , Choi T. , Cheong S.-W.
Published: August 2009

Cryogenic-temperature technology is a promising and practical solution for the intense demand for high performance electronics. By utilizing the unique hysteretic behavior of perovskite (La,Pr,Ca)MnO3 observed either as a function of temperature and/or applied electric fields, we discovered low-temperature phases with either metallic and/or insulating resistance values. Low temperature resistivity state can be repeatedly switched by applying various voltage pulses. Resistance value of each phase is stable in time and reproducible after many switching cycles. Phases with intermediate resistance values can also be repeatedly stabilized. The behaviors reported here can be harnessed for cryogenic-temperature phase-change random access memory applications.
Avalanche multiplication of photocarriers in nanometer-sized silicon dot layers
Authors: Hirano Yoshiyuki , Okamoto Kenta , Yamazaki Susumu , Koshida Nobuyoshi
Published: August 2009

Photocurrent under reverse bias has been studied for metal-semiconductor diodes consisting of nanocrystalline Si dot (3.1 nm in mean diameter) embedded in SiO2. The samples were prepared on n+-type Si wafers by sequential dry processing based on low-pressure chemical vapor deposition and subsequent thermal oxidation. The temperature dependence measurements show that the quantum efficiency under an electric field of 9×105 V/cm reaches 2400% at 77 K. This high quantum efficiency is presumably caused by the avalanche multiplication of photoexcited carriers in the Si-nanodot layers. The Si-nanodot layer is potentially useful as a highly sensitive image-sensor target compatible with low-voltage operation.
Generation of non-Gaussian statistics and coherent structures in ideal magnetohydrodynamics
Authors: Wan M. , Oughton S. , Servidio S. , Matthaeus W. H.
Published: August 2009

Spectral method simulations of ideal magnetohydrodynamics are used to investigate production of coherent small scale structures, a feature of fluid models that is usually associated with inertial range signatures of nonuniform dissipation, and the associated emergence of non-Gaussian statistics. The near-identical growth of non-Gaussianity in ideal and nonideal cases suggests that generation of coherent structures and breaking of self-similarity are essentially ideal processes. This has important implications for understanding the origin of intermittency in turbulence.
Charge fluctuations and Hall effect in dusty plasmas
Authors: Pandey B. P. , Vladimirov S. V.
Published: August 2009

In a magnetized dusty plasma, Hall effect can arise due to collisional processes when, e.g., ion-dust collision decouples the ions from the magnetic field. In this case, due to the dust stoppage of the ions, the Hall electric field can be generated over large scales. The same collisional processes are also responsible for dust charge fluctuations. Therefore, the Hall effect and dust charge fluctuations are intricately linked to each other through the same mechanism. The inertial scale over which the Hall effect is dynamically important depends not only on the value of the grain charge times the ratio of the grain to the plasma (ion) number densities but also on the ratio of the ion-dust to the electron-dust collision frequencies. This scale can become arbitrarily large when these collision frequencies are comparable. We show that the charge dynamics, though linked to the Hall scale, does not directly affect the low frequency waves in the medium. Since charge fluctuation modifies the length scale over which Hall operates, the normal mode in such a medium is only indirectly affected although wave suffers weak damping due to collision.
Versatile Ligands for the Construction of Layered Metal-Containing Networks
Authors: Aakeröy Christer B. , Hussain Izhar , Forbes Safiyyah , Desper John
Published: August 2009

The synthetic opportunities furnished by organic synthesis and the inherent structure-directing possibilities of coordination complexes have been combined in the assembly of a series of layered metal-containing hybrid materials. The supramolecular assembly relies on self-complementary non-covalent interactions, and in five of the six structures presented herein, N–H···O=C hydrogen bonds between acetamide moieties on neighbouring ligands provide the primary structure-direction tool as intended. The distances between metal ions are controlled by ligand···ligand hydrogen bonds and reside within a narrow and tuneable range. The following crystal structures are reported: [Cu(4-(3-pyridyl)-1-acetamidobenzene)2(1,1,1,5,5,5-hexafluoro-2,4-pentanedione)2] 1; [Cu(4-(acetamidomethyl)pyridine)2(1,1,1,5,5,5-hexafluoro-2,4-pentanedione)2]·2CH2Cl2 2; [Cu(3-acetamidopyridine)2(1,1,1,5,5,5-hexafluoro-2,4-pentanedione)2] 3; [Ni(3-acetamidopyridine)2(1,3-diphenyl-1,3-propanedione)2]·2CH2Cl2 4; [Ni(3-acetamidopyridine)2(1,3-diphenyl-1,3-propanedione)2] 5; and [Co(2-acetamidopyridine)2(1,3-diphenyl-1,3-propanedione)2]·2CH2Cl2 6.