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Homogeneous Sample (homogeneous + sample)
Selected AbstractsAcute Hypervolaemia Improves Arterial Oxygen Pressure in Athletes with Exercise-Induced HypoxaemiaEXPERIMENTAL PHYSIOLOGY, Issue 4 2003Gerald S. Zavorsky The aim of this study was to determine the effect of acute plasma volume expansion on arterial blood-gas status during 6.5 min strenuous cycling exercise comparing six athletes with and six athletes without exercise-induced arterial hypoxaemia (EIAH). We hypothesized that plasma volume expansion could improve arterial oxygen pressure in a homogeneous sample of athletes - those with EIAH. In this paper we have extended the analysis and results of our recently published surprising findings that lengthening cardiopulmonary transit time did not improve arterial blood-gas status in a heterogeneous sample of endurance cyclists. One 500 ml bag of 10% Pentastarch (infusion condition) or 60 ml 0.9% saline (placebo) was infused prior to exercise in a randomized, double-blind fashion on two different days. Power output, cardiac output, oxygen consumption and arterial blood gases were measured during strenuous exercise. Cardiac output and oxygen consumption were not affected by acute hypervolaemia. There were group × condition interaction effects for arterial oxygen pressure and alveolar-arterial oxygen pressure difference, suggesting that those with hypoxaemia experienced improved arterial oxygen pressure (+4 mmHg) and lower alveolar-arterial oxygen pressure difference (-2 mmHg) with infusion. In conclusion, acute hypervolaemia improves blood-gas status in athletes with EIAH. The impairment of gas exchange occurs within the first minute of exercise, and is not impaired further throughout the remaining duration of exercise. This suggests that arterial oxygen pressure is only minimally mediated by cardiac output. [source] Auditory orienting and inhibition of return in mild traumatic brain injury: A FMRI studyHUMAN BRAIN MAPPING, Issue 12 2009Andrew R. Mayer Abstract The semiacute phase of mild traumatic brain injury (mTBI) is associated with deficits in the cognitive domains of attention, memory, and executive function, which previous work suggests may be related to a specific deficit in disengaging attentional focus. However, to date, there have only been a few studies that have employed dynamic imaging techniques to investigate the potential neurological basis of these cognitive deficits during the semiacute stage of injury. Therefore, event-related functional magnetic resonance imaging was used to investigate the neurological correlates of attentional dysfunction in a clinically homogeneous sample of 16 patients with mTBI during the semiacute phase of injury (<3 weeks). Behaviorally, patients with mTBI exhibited deficits in disengaging and reorienting auditory attention following invalid cues as well as a failure to inhibit attentional allocation to a cued spatial location compared to a group of matched controls. Accordingly, patients with mTBI also exhibited hypoactivation within thalamus, striatum, midbrain nuclei, and cerebellum across all trials as well as hypoactivation in the right posterior parietal cortex, presupplementary motor area, bilateral frontal eye fields, and right ventrolateral prefrontal cortex during attentional disengagement. Finally, the hemodynamic response within several regions of the attentional network predicted response times better for controls than for patients with mTBI. These objective neurological findings represent a potential biomarker for the behavioral deficits in spatial attention that characterize the initial recovery phase of mTBI. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc. [source] The effects of acute exercise on cognitive functioning and cigarette cravings during temporary abstinence from smokingHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 3 2008Kate Janse Van Rensburg Abstract Background Abstinence from smoking is associated with increased cravings, risk of accidents and self-reported poor concentration. A single exercise session can reduce cravings and self-reported poor concentration and can enhance cognitive performance among non-smokers. Objective To assess whether acute exercise impacts on the cognitive performance and cravings of abstaining smokers. Methods In a counterbalanced cross-over design, participants (n,=,23) did a 15,min passive or exercise condition, following cigarette abstinence. Cognitive functioning was measured by a computerised version of the Stroop colour-word interference task. Cravings were measured using the 10-item, 2-factor QSU-Brief and a single item for ,desire to smoke'. Measures were recorded at baseline, immediately post, 5, 10 and 15-min post treatment. Results A 2-way ANOVA showed no significant condition,×,time interaction for cognitive functioning. Significant interaction effects were found for desire to smoke, QSU Factor 1 (desire,behave) and 2 (desire,affect). Exercise reduced cravings for up to 15,min post treatment. Discussion Findings support previous research that acute exercise reduces cravings to smoke. Future research should determine if exercise can enhance other objective aspects of cognitive performance, and repeat the present study with a more homogeneous sample, in terms of Stroop performance. Conclusion This is the first study to show that exercise can reduce both factors of the QSU-Brief, but effects on cognitive functioning were not observed. Copyright © 2008 John Wiley & Sons, Ltd. [source] Possibilities of using near infrared reflectance/transmittance spectroscopy for determination of polymeric protein in wheatJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2007Éva Scholz Abstract Possibilities of using near-infrared reflectance and near-infrared transmittance (NIR/NIT) spectroscopic techniques for detecting differences in amount and size distribution of polymeric proteins in wheat were investigated. To evaluate whether differences in polymeric protein due to genetic or environmental variations were detectable by NIR/NIT techniques, wheat materials of different background were used. Size-exclusion high-performance liquid chromatography was applied to detect variation in polymeric protein. Partial least squares regression gave high R2 values between many protein parameters and NIR/NIT spectra (particularly second-derivative spectra of NIR 1100,2500 nm region) of flours, while no such relationship was found for whole wheat grains. Most and highest correlations were found for total amount of extractable and unextractable proteins and monomer/polymer protein ratio. Some positive relationships were found between percentage of total unextractable polymeric protein in the total polymeric protein and percentage of large unextractable polymeric protein in the total large polymeric protein and NIR/NIT spectra. Thus, it was possible to detect differences in polymeric proteins with NIR/NIT techniques. The highest amount of positive correlations between NIR/NIT spectra and protein parameters was found to be due to environmental influences. Some correlations were found for breeding lines with a broad variation in gluten strength and polymeric protein composition, while a more homogeneous sample showed less correlation. Thereby, detection of variation in amount and size distribution of polymeric protein due to cultivar differences with NIR/NIT methods might be difficult. Copyright © 2007 Society of Chemical Industry [source] A homogeneous sample of sub-damped Lyman systems , IV.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2007Global metallicity evolution ABSTRACT An accurate method to measure the abundance of high-redshift galaxies involves the observation of absorbers along the line of sight towards a background quasar. Here, we present abundance measurements of 13 z, 3 sub-damped Lyman , (sub-DLA) systems (quasar absorbers with H i column density in the range 19 < log N(H i) < 20.3 cm,2) based on high-resolution observations with the VLT UVES spectrograph. These observations more than double the amount of metallicity information for sub-DLAs available at z > 3. These new data, combined with other sub-DLA measurements from the literature, confirm the stronger evolution of metallicity with redshift for sub-DLAs than for the classical damped Lyman , absorbers. In addition, these observations are used to compute for the first time, using photoionization modelling in a sample of sub-DLAs, the fraction of gas that is ionized. Based on these results, we calculate that sub-DLAs contribute no more than 6 per cent of the expected amount of metals at z, 2.5. We therefore conclude that, even if sub-DLAs are found to be more metal-rich than classical DLAs, their contribution is insufficient to solve the so-called ,missing-metals' problem. [source] Correlations between diffuse interstellar bands and atomic linesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2004G. A. Galazutdinov ABSTRACT We present and discuss correlations between strengths of the well-known, strong interstellar atomic lines of K i and Ca ii, and four selected, strong unidentified diffuse interstellar bands (DIBs): 5780, 5797, 5850 and 6614. In order to analyse a homogeneous sample of echelle high-resolution spectra it has been chosen to use measurements from Terskol Observatory in Northern Caucasus plus a selected number of higher resolution observations performed using other instruments. We demonstrate that the strength of certain DIBs correlate well with neutral potassium lines and to a much lower degree with ionized calcium lines. This fact suggests that the degree of irradiation of a cloud with UV photons, capable to ionize interstellar atoms, plays a crucial role in the formation/maintenance of certain molecular species: possible carriers of DIBs. [source] Association study between two variants in the DOPA decarboxylase gene in bipolar and unipolar affective disorder,AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 5 2002Esther Jahnes Abstract Irregularities of dopaminergic and serotonergic neurotransmission have been implicated in a variety of neuropsychiatric disorders. DOPA decarboxylase (DDC), also known as aromatic L -amino acid decarboxylase, is an enzyme involved directly in the synthesis of dopamine and serotonin and indirectly in the synthesis of noradrenaline. Therefore, the DDC gene can be considered as a candidate gene for affective disorders. Recently, two novel variants were reported in the DDC gene: a 1-bp deletion in the promoter and a 4-bp deletion in the untranslated exon 1. Subsequently, an association case,control study including 112 English patients and 80 Danish patients with bipolar affective disorder (BPAD) revealed a significant association with the 1-bp deletion. This finding prompted us to analyze whether this effect was also present in a larger and ethnically homogeneous sample of 228 unrelated German patients with BPAD (208 patients with BP I disorder, 20 patients with BP II disorder), 183 unrelated patients with unipolar affective disorder (UPAD), and 234 healthy control subjects. For both BPAD and UPAD we could not detect a genetic association with either variant. Thus, our results do not support an involvement of the 1-bp or 4-bp deletion within the DDC gene in the etiology of affective disorders. © 2002 Wiley-Liss, Inc. [source] A method for quantitative determination of deuterium content in biological materialRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2005Yihui He A method was developed for quantitative determination of deuterium incorporated into live organisms or biological macromolecules. The deuterated biological material was mixed with a bovine serum albumin (BSA) supporter to make a homogeneous sample for which the ,D value (vs. VSMOW) was analyzed using a dual-inlet gas isotope mass spectrometer. The method is described in detail, and the equation for calculation of deuterium content is presented, i.e., C,=,1/500,×,k,×,RVSMOW,×,C,×,106 ppm. Deuterated hepatitis A virus (HAV) RNA and BSA were systematically investigated. The results demonstrate that the method is capable of direct measurement of deuterium content, and is highly repeatable and reliable with a standard deviation of ±3,. It is stressed that the quantity of deuterated sample required is extremely small as a result of using BSA as supporter. The method may be applied in many fields, and has the strengths of simplicity, relative cheapness, and robustness. Copyright © 2005 John Wiley & Sons, Ltd. [source] Flat galaxies in the SDSS DR6ASTRONOMISCHE NACHRICHTEN, Issue 9-10 2009S.J. Kautsch Abstract This study presents the fractions of different spiral galaxy types from a complete and homogeneous sample of 15 127 edge-on disk galaxies extracted from the sixth data release from the Sloan Digital Sky Survey. The sample is divided in broad morphological classes and sub types consisting of galaxies with bulges, intermediate types and galaxies which appear bulgeless. A small fraction of disky irregulars is also detected. The morphological separation is based on automated classification criteria which resemble the bulge sizes and the flatness of the disks. Each of these broad classes contains about 1/3 of the total sample. Using strict criteria for selecting pure bulgeless galaxies leads to a fraction of 15 % of simple disk galaxies (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Edge-on disk galaxies in the SDSS DR6: Fractions of bulgeless and other disk galaxiesASTRONOMISCHE NACHRICHTEN, Issue 1 2009S.J. KautschArticle first published online: 2 JAN 200 Abstract The aim of this study is to determine the fractions of different spiral galaxy types, especially bulgeless disks, from a complete and homogeneous sample of 15 127 edge-on disk galaxies extracted from the sixth data release from the Sloan Digital Sky Survey. The sample is divided in broad morphological classes and sub types consisting of galaxies with bulges, intermediate types and galaxies which appear bulgeless. A small fraction of disky irregulars is also detected. The morphological separation is based on automated classification criteria which resemble the bulge sizes and the flatness of the disks. Each of these broad classes contains about 1/3 of the total sample. Using strict criteria for selecting pure bulgeless galaxies leads to a fraction of 15% of simple disk galaxies. We compare this fraction to other galaxy catalogs and find an excellent agreement of the observed frequency of bulgeless galaxies. Although the fraction of simple disk galaxies in this study does not represent a "cosmic" fraction of bulgeless galaxies, it shows that the relative abundance of pure disks is comparable to other studies and offers a profound value of the frequency of simple disks in the local Universe. This fraction of simple disks emphasizes the challenge for formation and evolution models of disk galaxies since these models are hard pressed to explain the observed frequency of these objects (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Modeling normal and pathological processes through skin tissue engineeringMOLECULAR CARCINOGENESIS, Issue 8 2007Marta Garcia Abstract Skin tissue engineering emerged as an experimental regenerative therapy motivated primarily by the critical need for early permanent coverage of extensive burn injuries in patients with insufficient sources of autologous skin for grafting. With time, the approach evolved toward a wider range of applications including disease modeling. We have established a skin-humanized mouse model system consisting in bioengineered human-skin-engrafted immunodeficient mice. This new model allows to performing regenerative medicine, gene therapy, genomics, and pathology studies in a human context on homogeneous samples. Starting from skin cells (keratinocytes and fibroblasts) isolated from normal donor skin or patient's biopsies, we have been able to deconstruct-reconstruct several inherited skin disorders including genodermatoses and cancer-prone diseases in a large number of skin humanized mice. In addition, the model allows conducting studies in normal human skin to gain further insight into physiological processes such as wound healing or UV-responses. © 2007 Wiley-Liss, Inc. [source] Allelic variation of a BalI polymorphism in the DRD3 gene does not influence susceptibility to bipolar disorder: Results of analysis and meta-analysisAMERICAN JOURNAL OF MEDICAL GENETICS, Issue 4 2001Gareth Elvidge Abstract Bipolar disorder is a major psychiatric illness that has evidence for a significant genetic contribution toward its development. In recent years, the BalI RFLP (restriction fragment length polymorphism) in the dopamine D3 receptor gene has been examined as a possible susceptibility factor for both schizophrenia and bipolar disorder. While analysis in schizophrenia has produced examples of increased homozygosity in patients, less encouraging results have been found for bipolar disorder. Recently, however, a family-based association study has found a significant excess of allele 1 and allele 1,containing genotypes in transmitted alleles to bipolar probands over nontransmitted controls. In a large bipolar case control sample (n,=,454), we have been unable to replicate the family-based association study (chi-square,=,0.137, P,=,0.71, 1 df) or detect an effect similar to the positive homozygosity findings in schizophrenia (chi-square,=,0.463, P,=,0.50, 1 df). A meta-analysis of previous association studies also revealed no difference in allele distributions between bipolar patients and controls for this polymorphism in ethnically homogeneous samples (odds ratio, OR,,=,1.04; P,=,0.60; 95% confidence interval, CI,,=,0.89,1.20). In view of this evidence, we conclude that variation at the BalI RFLP is not an important factor influencing the susceptibility to bipolar disorder. It remains possible, however, that other sequence variations within the DRD3 gene could play a role. © 2001 Wiley-Liss, Inc. [source] Practitioner Review: Bridging the gap between research and clinical practice in pediatric obesityTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 2 2007Elissa Jelalian Background:, Pediatric obesity is a significant public health concern, with rising prevalence rates in both developed and developing countries. This is of particular significance given that overweight children and adolescents are at increased risk for multiple medical comorbidities, as well as psychosocial and behavioral difficulties. The current review highlights findings from the empirical pediatric obesity treatment literature, with particular attention to diet, physical activity, and behavior interventions. Evaluation and treatment considerations relevant to working with overweight children and adolescents with psychiatric comorbidities are reviewed. Methods:, Review of the relevant treatment literature, with a focus on randomized clinical trials, was conducted. Recommendations regarding treatment of children and adolescents with psychiatric comorbidities are based on relevant prospective studies of the relationship between weight status and psychological variables and studies with adult populations. Results:, Well-established pediatric weight control interventions have been conducted in research settings. These studies provide a starting point, but are limited by homogeneous samples that may exclude participants with psychiatric comorbidities. Practitioners treating obese children and adolescents with psychiatric disorders are encouraged to assess individual, familial, and contextual variables specific to weight (e.g., motivation and existing support to change current eating and physical activity patterns, extent of weight-related conflict within family, impact of weight on current functioning) in order to prioritize treatment objectives. Conclusions:, The review concludes with a discussion of current empirical and practical challenges, including explicitly targeting obese children and adolescents with psychiatric concerns and determining appropriateness of pursuing weight control interventions in this population. [source] | |||||||||||||||||||