bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of ventricular rate adaptation as a predictor of arrhythmic risk
Authors: Pueyo Esther , Husti Zoltán , Hornyik Tibor , Baczkó István , Laguna Pablo , Varró András , Rodríguez Blanca
Published: March 2010

Protracted QT interval (QTI) adaptation to abrupt heart rate (HR) changes has been identified as a clinical arrhythmic risk marker. This study investigates the ionic mechanisms of QTI rate adaptation and its relationship to arrhythmic risk. Computer simulations and experimental recordings in human and canine ventricular tissue were used to investigate the ionic basis of QTI and action potential duration (APD) to abrupt changes in HR with a protocol commonly used in clinical studies. The time for 90% QTI adaptation is 3.5 min in simulations, in agreement with experimental and clinical data in humans. APD adaptation follows similar dynamics, being faster in midmyocardial cells (2.5 min) than in endocardial and epicardial cells (3.5 min). Both QTI and APD adapt in two phases following an abrupt HR change: a fast initial phase with time constant < 30 s, mainly related to L-type calcium and slow-delayed rectifier potassium current, and a second slow phase of >2 min driven by intracellular sodium concentration ([Na+]i) dynamics. Alterations in [Na+]i dynamics due to Na+/K+ pump current inhibition result in protracted rate adaptation and are associated with increased proarrhythmic risk, as indicated by action potential triangulation and faster L-type calcium current recovery from inactivation, leading to the formation of early afterdepolarizations. In conclusion, this study suggests that protracted QTI adaptation could be an indicator of altered [Na+]i dynamics following Na+/K+ pump inhibition as it occurs in patients with ischemia or heart failure. An increased risk of cardiac arrhythmias in patients with protracted rate adaptation may be due to an increased risk of early afterdepolarization formation.
Defects in oxygen supply to skeletal muscle of prediabetic ZDF rats
Authors: Ellis Christopher G. , Goldman Daniel , Hanson Madelyn , Stephenson Alan H. , Milkovich Stephanie , Benlamri Amina , Ellsworth Mary L. , Sprague Randy S.
Published: March 2010

In humans, prediabetes is characterized by marked increases in plasma insulin and near normal blood glucose levels as well as microvascular dysfunction of unknown origin. Using the extensor digitorum longus muscle of 7-wk inbred male Zucker diabetic fatty rats fed a high-fat diet as a model of prediabetes, we tested the hypothesis that hyperinsulinemia contributes to impaired O2 delivery in skeletal muscle. Using in vivo video microscopy, we determined that the total O2 supply to capillaries in the extensor digitorum longus muscle of prediabetic rats was reduced to 64% of controls with a lower O2 supply rate per capillary and higher O2 extraction resulting in a decreased O2 saturation at the venous end of the capillary network. These findings suggest a lower average tissue Po2 in prediabetic animals. In addition, we determined that insulin, at concentrations measured in humans and Zucker diabetic fatty rats with prediabetes, inhibited the O2-dependent release of ATP from rat red blood cells (RBCs). This inability to release ATP could contribute to the impaired O2 delivery observed in rats with prediabetes, especially in light of the finding that the endothelium-dependent relaxation of resistance arteries from these animals is not different from controls and is not altered by insulin. Computational modeling confirmed a significant 8.3-mmHg decrease in average tissue Po2 as well as an increase in the heterogeneity of tissue Po2, implicating a failure of a regulatory system for O2 supply. The finding that insulin attenuates the O2-dependent release of ATP from RBCs suggests that this defect in RBC physiology could contribute to a failure in the regulation of O2 supply to meet the demand in skeletal muscle in prediabetes.
Decreased steady-state cerebral blood flow velocity and altered dynamic cerebral autoregulation during 5-h sustained 15% O2 hypoxia
Authors: Nishimura Naoko , Iwasaki Ken-ichi , Ogawa Yojiro , Aoki Ken
Published: March 2010

Effects of hypoxia on cerebral circulation are important for occupational, high-altitude, and aviation medicine. Increased risk of fainting might be attributable to altered cerebral circulation by hypoxia. Dynamic cerebral autoregulation is reportedly impaired immediately by mild hypoxia. However, continuous exposure to hypoxia causes hyperventilation, resulting in hypocapnia. This hypocapnia is hypothesized to restore impaired dynamic cerebral autoregulation with reduced steady-state cerebral blood flow (CBF). However, no studies have examined hourly changes in alterations of dynamic cerebral autoregulation and steady-state CBF during sustained hypoxia. We therefore examined cerebral circulation during 5-h exposure to 15% O2 hypoxia and 21% O2 in 13 healthy volunteers in a sitting position. Waveforms of blood pressure and CBF velocity in the middle cerebral artery were measured using finger plethysmography and transcranial Doppler ultrasonography. Dynamic cerebral autoregulation was assessed by spectral and transfer function analysis. As expected, steady-state CBF velocity decreased significantly from 2 to 5 h of hypoxia, accompanying 2- to 3-Torr decreases in end-tidal CO2 (ETCO2). Furthermore, transfer function gain and coherence in the very-low-frequency range increased significantly at the beginning of hypoxia, indicating impaired dynamic cerebral autoregulation. However, contrary to the proposed hypothesis, indexes of dynamic cerebral autoregulation showed no significant restoration despite ETCO2 reductions, resulting in persistent higher values of very-low-frequency power of CBF velocity variability during hypoxia (214 ± 40% at 5 h of hypoxia vs. control) without significant increases in blood pressure variability. These results suggest that sustained mild hypoxia reduces steady-state CBF and continuously impairs dynamic cerebral autoregulation, implying an increased risk of shortage of oxygen supply to the brain.
Why wrapping premature neonates to prevent hypothermia can predispose to overheating
Authors: Agourram Bouchra , Bach Véronique , Tourneux Pierre , Krim Gérard , Delanaud Stéphane , Libert Jean-Pierre
Published: March 2010

Wrapping low-birth-weight neonates in a plastic bag prevents body heat loss. A bonnet can also be used, since large amounts of heat can be lost from the head region, but may provide too much thermal insulation, thus increasing the risk of overheating. We assessed the time required to reach warning body temperature ( t38°C), heat stroke ( t40°C), or extreme value ( t43°C) in a mathematical model that involved calculating various local body heat losses. Simulated heat exchanges were based on body surface temperature distribution measured in preterm neonates exposed to 33°C air temperature (relative air humidity: 35%; air velocity: <0.1 m/s) and covered (torso and limbs) or not with a transparent plastic bag. We also compared metabolic heat production with body heat losses when a bonnet (2 or 3.5 mm thick) covered 10%, 40%, or 100% of the head. Wrapping neonates in a bag (combined or not with a bonnet) does not induce a critical situation as long as metabolic heat production does not increase. When endogenous heat production rises, t38°Cranged between 75 and 287, t40°Cbetween 185 and 549, and t43°Cbetween 287 and 702 min. When this increase was accompanied by a fall in skin temperature, overheating risk was accentuated (37 ≤ t38°C≤ 45; 99 ≤ t40°C≤117; 169 ≤ t43°C≤ 194 min). Thus plastic bag and bonnet may result in hyperthermia but only when metabolic heat production rises while skin temperature falls (impeding body heat losses), as can sometimes happen with fever.
Circulating cytokine levels in mice with heart failure are etiology dependent
Authors: Vistnes Maria , Wæhre Anne , Nygård Ståle , Sjaastad Ivar , Andersson Kristin B. , Husberg Cathrine , Christensen Geir
Published: March 2010

Objectives: The aim of this study was to examine whether alterations in circulating cytokine levels are dependent on the etiology of myocardial hypertrophy and heart failure (HF). Background: Several heart diseases are associated with altered levels of circulating cytokines. Cytokines are regarded as possible therapeutic targets or biomarkers, but such approaches are currently not in clinical use. If alterations in circulating cytokines are etiology dependent, this should be taken into consideration when using cytokines as disease markers and therapeutic targets. Methods: The serum levels of 25 cytokines were quantified with Luminex and/or ELISA in four murine models of heart disease: banding of the ascending aorta (AB) or the pulmonary artery (PB), myocardial infarction (MI), and a cardiomyopathy model with inducible cardiomyocyte-specific knockout of the sarco(endo)plasmatic reticulum Ca2+-ATPase (SERCA2KO). Results: No increase in circulating cytokine levels were found in mice 1 wk after AB, although substantial myocardial hypertrophy was present. After 1 wk of MI, only interleukin (IL)-18 was increased. In the SERCA2KO mice with HF, circulating levels of IL-1α, IL-2, IL-3, IL-6, IL-9, IL-10, IL-12p40, eotaxin, granulocyte-colony stimulating factor (G-CSF), interferon-γ, monocyte chemoattractant protein-1, macrophage inflammatory protein-1β were increased, and in mice with PB, IL-1α, IL-6, G-CSF, and monokine induced by gamma-interferon showed elevated levels. Conclusions: Serum levels of cytokines in mice with HF vary depending on the etiology. Increased serum levels of several cytokines were found in models with increased right ventricular afterload, suggesting that the cytokine responses result primarily from systemic congestion.
Impaired organization and function of myofilaments in single muscle fibers from a mouse model of Pompe disease
Authors: Xu Sengen , Galperin Mikhail , Melvin Gary , Horowits Robert , Raben Nina , Plotz Paul , Yu Leepo
Published: March 2010

Pompe disease, a deficiency of lysosomal acid α-glucosidase, is a disorder of glycogen metabolism that can affect infants, children, or adults. In all forms of the disease, there is progressive muscle pathology leading to premature death. The pathology is characterized by accumulation of glycogen in lysosomes, autophagic buildup, and muscle atrophy. The purpose of the present investigation was to determine if myofibrillar dysfunction in Pompe disease contributes to muscle weakness beyond that attributed to atrophy. The study was performed on isolated myofibers dissected from severely affected fast glycolytic muscle in the α-glucosidase knockout mouse model. Psoas muscle fibers were first permeabilized, so that the contractile proteins could be directly relaxed or activated by control of the composition of the bathing solution. When normalized by cross-sectional area, single fibers from knockout mice produced 6.3 N/cm2 of maximum Ca2+-activated tension compared with 12.0 N/cm2 produced by wild-type fibers. The total protein concentration was slightly higher in the knockout mice, but concentrations of the contractile proteins myosin and actin remained unchanged. Structurally, X-ray diffraction showed that the actin and myosin filaments, normally arranged in hexagonal arrays, were disordered in the knockout muscle, and a lower fraction of myosin cross bridges was near the actin filaments in the relaxed muscle. The results are consistent with a disruption of actin and myosin interactions in the knockout muscles, demonstrating that impaired myofibrillar function contributes to weakness in the diseased muscle fibers.
Hypoxia-induced vasodilation and effects of regional phentolamine in awake patients with sleep apnea
Authors: Moradkhan Raman , Spitnale Brett , McQuillan Patrick , Hogeman Cynthia , Gray Kristen S. , Leuenberger Urs A.
Published: March 2010

Obstructive sleep apnea (OSA) is associated with increased sympathetic nerve activity, endothelial dysfunction, and premature cardiovascular disease. To determine whether hypoxia is associated with impaired skeletal muscle vasodilation, we compared femoral artery blood flow (ultrasound) and muscle sympathetic nerve activity (peroneal microneurography) during exposure to acute systemic hypoxia (fraction of inspired oxygen 0.1) in awake patients with OSA ( n = 10) and controls ( n = 8). To assess the role of elevated sympathetic nerve activity, in a separate group of patients with OSA ( n = 10) and controls ( n = 10) we measured brachial artery blood flow during hypoxia before and after regional α-adrenergic block with phentolamine. Despite elevated sympathetic activity, in OSA the vascular responses to hypoxia in the leg did not differ significantly from those in controls [ P = not significant (NS)]. Following regional phentolamine, in both groups the hypoxia-induced increase in brachial blood flow was markedly enhanced (OSA pre vs. post, 84 ± 13 vs. 201 ± 34 ml/min, P < 0.002; controls pre vs. post 62 ± 8 vs. 140 ± 26 ml/min, P < 0.01). At end hypoxia after phentolamine, the increase of brachial blood flow above baseline was similar (OSA vs. controls +61 ± 16 vs. +48 ± 6%; P = NS). We conclude that despite high sympathetic vasoconstrictor tone and prominent sympathetic responses to acute hypoxia, hypoxia-induced limb vasodilation is preserved in OSA.
Differentiation of Y Chromosome in the X1X1X2X2/X1X2Y Sex Chromosome System of Hoplias malabaricus (Characiformes, Erythrinidae)
Authors: da Rosa R. , Laforga Vanzela A.L. , Rubert M. , Martins-Santos I.C. , Giuliano-Caetano L.
Published: March 2010

Six populations of Hoplias malabaricus from the Lower Paranapanema River were studied and showed 2n = 40 with metacentric/submetacentric chromosomes for females and 2n = 39 with m/sm chromosomes for males, thereby revealing a multiple sex chromosome system of the X1X1X2X2/X1X2Y type. The Y chromosome was the largest metacentric chromosome in all karyotypes. The heterochromatic blocks were located in a pericentromeric region of all pairs and in telomeric regions in some other pairs. A conspicuous pericentromeric C-band was detected in a single pair, equivalent to the X1 chromosome. No markers on X2 chromosomes were detected, but they could be identified by their size. The females displayed the same distribution of C and chromomycin A3 bands and 18S rDNA sites among the populations. However, the males exhibited differences in both number and position of Giemsa C-bands on the Y chromosome, which were also evident after Chromomycin A3 banding and FISH with the 18S rDNA probe. These cytogenetic tools allowed for the identification of possible mechanisms involved in the differentiation and evolution of the Y chromosome.
Applying a Theory-Based Framework to Understand Public Knowledge of Genetic Risk Factors: A Case for the Distinction between How-To Knowledge and Principles Knowledge
Authors: Smerecnik C.M.R. , Mesters I. , de Vries N.K. , de Vries H.
Published: March 2010

Objective: Using E.M. Rogers’s knowledge framework as presented in his seminal innovation-decision process, this paper aims to present an overview of the general public’s knowledge of genetics. It also makes a first attempt to examine the statistical validity of this framework. Methods: A sample of 2,500 members of the Dutch general population was presented with a questionnaire containing measures of 3 increasingly complex forms of knowledge: awareness knowledge, (practical) how-to knowledge and (theoretical) principles knowledge. Results: The general public seems to be moderately aware of genetic risk factors for multifactorial diseases. In general, how-to knowledge seems fair, whereas principles knowledge is limited and superficial. Additional analyses provided empirical evidence for the distinction between awareness knowledge, how-to knowledge and principles knowledge. Conclusion: The innovation-decision process, and specifically Rogers’s knowledge framework, provides a useful tool for public education in genetics. Future research may build upon and extend our findings by examining the persuasion, decision, implementation, and possibly the confirmation stages of the innovation-decision process concerning genetic education.
Pathogenesis of Arteriovenous Malformations in the Absence of Endoglin
Authors: Mahmoud Marwa , Allinson Kathleen R. , Zhai Zhenhua , Oakenfull Rachael , Ghandi Pranita , Adams Ralf H. , Fruttiger Marcus , Arthur Helen M.
Published: March 2010

Rationale
:

Arteriovenous malformations (AVMs) result in anomalous direct blood flow between arteries and veins, bypassing the normal capillary bed. Depending on size and location, AVMs may lead to severe clinical effects including systemic cyanosis (pulmonary AVMs), hemorrhagic stroke (cerebral AVMs) and high output cardiac failure (hepatic AVMs). The factors leading to AVM formation are poorly understood, but patients with the familial disease hereditary hemorrhagic telangiectasia (HHT) develop AVMs at high frequency. As most HHT patients have mutations in
ENG
(endoglin) or
ACVRL1
(activin receptor-like kinase 1), a better understanding of the role of these genes in vascular development is likely to reveal the etiology of AVM formation.

Objective
:

Using a mouse with a conditional mutation in the
Eng
gene, we investigated the sequence of abnormal cellular events occurring during development of an AVM.

Methods and Results
:

In the absence of endoglin, subcutaneous Matrigel implants in adult mice were populated by reduced numbers of new blood vessels compared with controls, and resulted in local venous enlargement (venomegaly). To investigate abnormal vascular responses in more detail, we turned to the more readily accessible vasculature of the neonatal retina. Endoglin-deficient retinas exhibited delayed remodeling of the capillary plexus, increased proliferation of endothelial cells and localized AVMs. Muscularization of the resulting arteriovenous shunts appeared to be a secondary response to increased blood flow.

Conclusions
:

AVMs develop when an angiogenic stimulus is combined with endoglin depletion. Moreover, AVM formation appears to result from the combination of delayed vascular remodeling and an inappropriate endothelial cell proliferation response in the absence of endoglin.
Longitudinal Distribution of Mechanical Stresses in Carotid Plaques of Symptomatic Patients
Authors: Thrysøe Samuel A. , Oikawa Minako , Yuan Chun , Eldrup Nikolaj , Klærke Anette , Paaske William P. , Falk Erling , Kim W. Yong , Nygaard Jens Vinge
Published: March 2010

Background and Purpose—

Mechanical stress may contribute to plaque rupture in patients with carotid atherosclerosis. We determined longitudinal mechanical stresses in carotid atherosclerotic plaques and compared them with known markers of plaque vulnerability.

Methods—

Nineteen symptomatic patients scheduled for carotid endarterectomy underwent carotid MRI with a multicontrast protocol to characterize plaque morphology and geometry. Longitudinal 2-dimensional computational models were generated from the MRI data, and the mechanical stresses were calculated.

Results—

Peak longitudinal mechanical stresses occurred predominantly in the shoulder regions of the carotid plaque and correlated inversely with fibrous cap thickness (

r
s

=−0.61;
P
=0.01), and increasing degrees of stenosis (

r
s

=0.71;
P
=0.003). Peak stress levels were asymmetrically distributed longitudinally, with 50% occurring proximal to the maximal stenosis, 25% at the point of maximal stenosis, and 25% distal to the maximal stenosis.

Conclusion—

The peak longitudinal mechanical stresses in the fibrous caps of symptomatic patients with carotid atherosclerotic stenosis were located at known predilection sites for plaque rupture, suggesting that mechanical stresses may play a role in plaque destabilization.
End-Diastolic Velocity Increase Predicts Recanalization and Neurological Improvement in Patients With Ischemic Stroke With Proximal Arterial Occlusions Receiving Reperfusion Therapies
Authors: Alexandrov Andrei V. , Tsivgoulis Georgios , Rubiera Marta , Vadikolias Konstantinos , Stamboulis Elefterios , Molina Carlos A. , Alexandrov Anne W.
Published: March 2010

Background and Purpose—

It is unknown how little flow velocity improvement is necessary to achieve recanalization and clinical recovery. We sought to investigate which flow velocity parameter was associated with complete recanalization/reperfusion and neurological improvement in patients receiving reperfusion therapies.

Methods—

Patients with proximal intracranial occlusions were treated with systemic or intra-arterial tissue plasminogen activator within 6 hours from symptom onset. Consecutive peak systolic and end-diastolic (EDV) velocities were measured during continuous transcranial Doppler monitoring. Recanalization was graded with Thrombolysis in Brain Ischemia grades. Neurological and functional outcomes were assessed by the National Institutes of Health Stroke Scale and modified Rankin Scale scores.

Results—

Of 36 patients (mean age 57±19 years, median National Institutes of Health Stroke Scale 15 points, interquartile range 9), 13 (36%) achieved complete recanalization and those had greater EDV increase during transcranial Doppler monitoring (15±11 cm/s versus 6±10 cm/s;
P
=0.001). Peak systolic velocity increase with complete recanalization was 25±11 cm/s (versus 20±25 cm/s with partial recanalization/persisting occlusion;
P
=0.123). Neurological improvement at 24 hours positively correlated to EDV increase (Spearman
r
=0.337,
P
=0.044) but not to peak systolic velocity (
r
=0.197,
P
=0.250). EDV increase at the end of monitoring was higher in patients with favorable functional outcome at 3 months (13±13 cm/s versus 4±8 cm/s;
P
=0.021). After adjustment for potential confounders, including age, stroke risk factors, and baseline stroke severity, a 10-cm/s increase in EDV was independently associated with a 3-point decline in the National Institutes of Health Stroke Scale score at 24 hours from baseline (95% CI: 0 to 5;
P
=0.045).

Conclusions—

A modest increase in the EDV as opposed to peak systolic velocity is associated with complete recanalization/reperfusion, early neurological improvement, and favorable functional outcome. Diastolic flow augmentation may represent a novel target for development of reperfusion therapies.
An Evaluation of the Distribution of Remote Automated Weather Stations (RAWS)
Authors: Horel John D. , Dong Xia
Published: March 2010

This study estimates whether surface observations of temperature, moisture, and wind at some stations in the continental United States are less critical than others for specifying weather conditions in the vicinity of those stations. Two-dimensional variational analyses of temperature, relative humidity, and wind were created for selected midday hours during summer 2008. This set of 8925 control analyses was derived from 5-km-resolution background fields and Remote Automated Weather Station (RAWS) and National Weather Service (NWS) observations within roughly 4° × 4° latitude–longitude domains. Over 570 000 cross-validation experiments were completed to assess the impact of removing each RAWS and NWS station. The presence of observational assets within relatively close proximity to one another is relatively common. The sensitivity to removing temperature, relative humidity, or wind observations varies regionally and depends on the complexity of the surrounding terrain and the representativeness of the observations. Cost savings for the national RAWS program by removing a few stations may be possible. However, nearly all regions of the country remain undersampled, especially mountainous regions of the western United States frequently affected by wildfires.
A Velocity Dealiasing Technique Using Rapidly Updated Analysis from a Four-Dimensional Variational Doppler Radar Data Assimilation System
Authors: Lim Eunha , Sun Juanzhen
Published: March 2010

A Doppler velocity dealiasing algorithm is developed within the storm-scale four-dimensional radar data assimilation system known as the Variational Doppler Radar Analysis System (VDRAS). The innovative aspect of the algorithm is that it dealiases Doppler velocity at each grid point independently by using three-dimensional wind fields obtained either from an objective analysis using conventional observations and mesoscale model output or from a rapidly updated analysis of VDRAS that assimilates radar data. This algorithm consists of three steps: preserving horizontal shear, global dealiasing using reference wind from the objective analysis or the VDRAS analysis, and local dealiasing. It is automated and intended to be used operationally for radar data assimilation using numerical weather prediction models.

The algorithm was tested with 384 volumes of radar data observed from the Next Generation Weather Radar (NEXRAD) for a severe thunderstorm that occurred during 15 June 2002. It showed that the algorithm was effective in dealiasing large areas of aliased velocities when the wind from the objective analysis was used as the reference and that more accurate dealiasing was achieved by using the continuously cycled VDRAS analysis.
A Multisodar Approach to Wind Profiling
Authors: Behrens Paul , Bradley Stuart , Wiens Travis
Published: March 2010

This paper presents the development of a multisodar mode from a five-beam sodar whereby a wind speed vector is found for sets of three acoustic beams. If the vertical beam is used, this mode enables the profiling of four wind speed measurements around the sodar. These multisodars can be used to investigate the spatial and temporal nature of winds in both flat and complex terrain. The spatial, temporal, and signal-to-noise qualities of the sodar signal in this mode are analyzed, and a metric for understanding the inhomogeneity of the atmosphere through cross-correlating opposing multisodars is developed. A driving factor for this work is developing the use of such sodar systems in complex terrain, where experimental measurements are traditionally difficult and expensive.
An Improved Method for Estimating the Wind Power Density Distribution Function
Authors: Morrissey Mark L. , Cook Werner E. , Greene J. Scott
Published: March 2010

The wind power density (WPD) distribution curve is essential for wind power assessment and wind turbine engineering. The usual practice of estimating this curve from wind speed data is to first estimate the wind speed probability density function (PDF) using a nonparametric or parametric method. The density function is then multiplied by one-half the wind speed cubed times the air density. Unfortunately, this means that minor errors in the estimation of the wind speed PDF can result in large errors in the WPD distribution curve because the cubic term in the WPD function magnifies the error. To avoid this problem, this paper presents a new method of estimating the WPD distribution curve through a direct estimation of the curve using a Gauss–Hermite expansion. It is demonstrated that the proposed method provides a much more reliable estimate of the WPD distribution curve.
The Dynamic and Thermodynamic Structures Associated with a Series of Heavy Precipitation Events over China during January 2008
Authors: Shi Xiaohui , Xu Xiangde , Lu Chungu
Published: March 2010

In the winter of 2008, China experienced once-in-50-yr (or once in 100 yr for some regions) snow and ice storms. These storms brought huge socio economical impacts upon the Chinese people and government. Although the storms had been predicted, their severity and persistence were largely underestimated. In this study, these cases were revisited and comprehensive analyses of the storms’ dynamic and thermodynamic structures were conducted. These snowstorms were also compared with U.S. east coast snowstorms. The results from this study will provide insights on how to improve forecasts for these kinds of snowstorms. The analyses demonstrated that the storms exhibited classic patterns of large-scale circulation common to these types of snowstorms. However, several physical processes were found to be unique and thought to have played crucial roles in intensifying and prolonging China’s great snowstorms of 2008. These include a subtropical high over the western Pacific, an upper-level jet stream, and temperature and moisture inversions. The combined effects of these dynamic and thermodynamic structures are responsible for the development of the storms into one of the most disastrous events in Chinese history.
Social Change and Socioeconomic Disparities in Health over the Life Course in China: A Cohort Analysis
Authors: Feinian Chen  , Yang Yang  , Guangya Liu
Published: March 2010

This article examines social stratification in individual health trajectories for multiple cohorts in the context of China’s dramatically changing macro-social environment. Using data from the China Health and Nutrition Survey, we find significant socioeconomic status (SES) differences in the mean level of health and that these SES differentials generally diverge over the life course. We also find strong cohort variations in SES disparities in the mean levels of health and health trajectories. The effect of education on health slightly decreases across successive cohorts. By contrast, the income gap in health trajectories diverges for earlier cohorts but converges for most recent cohorts. Both effects are more pronounced in rural areas. Given that these cohort effects are opposite those reported in recent U.S. studies, we discuss China’s unique social, economic, and political settings. We highlight the association between SES and health behaviors, China’s stage of epidemiologic transition, and the changing power of the state government and its implications for health care.
The New Politics of Community
Authors: Hill Collins Patricia
Published: March 2010

Ideas about community are especially prominent in late-twentieth-century U.S. society. The term community resonates throughout social policy, scholarship, popular culture, and everyday social interactions. It holds significance for different populations with competing political agendas (e.g., political groups of the right and the left invoke ideas of community yet have very different ideas in mind). No longer seen as naturally occurring, apolitical spaces to which one retreats to escape the pressures of modern life, communities of all sorts now constitute sites of political engagement and contestation. The new politics of community reveals how the idea of community constitutes an elastic political construct that holds a variety of contradictory meanings and around which diverse social practices occur. In this address, I analyze how reframing the idea of community as a political construct might provide new avenues for investigating social inequalities. I first explore the utility of community as a political construct for rethinking both intersecting systems of power and activities that are routinely characterized as ‘‘political.’’ Next, by examining five contemporary sites where community is either visibly named as a political construct or implicated in significant political phenomena, I investigate how the construct of community operates within contemporary power relations of class, gender, ethnicity, sexuality, age, ability, nation, and race. Finally, I explore the potential intellectual and political significance of these developments.
Drugs, Guns, and Disadvantaged Youths
Authors: Allen Andrea N. , Lo Celia C.
Published: March 2010

Guided by Anderson’s theory of the code of the street, this study explored social mechanisms linking individual-level disadvantage factors with the adoption of beliefs grounded in the code of the street and with drug trafficking and gun carrying—the co-occurring behavior shaping violence among young men in urban areas. Secondary data were employed from a sample of male inmates and a sample of male high school students. Data analysis indicated that the social disadvantage factor absent father significantly predicted this co-occurring behavior in the inmate sample, whereas the social disadvantage factor history of expulsion did so in the student sample. In both samples, race and adopting beliefs about gun carrying from the code of the street were significant predictors of drug trafficking and gun carrying. The results do not suggest that such code-based beliefs’ impact on drug trafficking and gun carrying differs by race. Implications for social policy are discussed.
Collective Trauma Transmission and Traumatic Reactions Among Descendants of Armenian Refugees
Authors: Karenian Hatsantour , Livaditis Miltos , Karenian Sirpouhi , Zafiriadis Kyriakos , Bochtsou Valentini , Xenitidis Kiriakos
Published: March 2010

Background: It has been suggested, mainly by case reports, that the collective trauma generated by mass calamities may be transmitted to, and have long-lasting effects on, new generations.

Aims: To investigate the psychological impact on contemporary Armenians of traumatic events suffered by Armenians during the period 1914—1918.

Methods: A descriptive, cross-sectional study investigating demographic and cultural characteristics of a population of 689 people of Armenian origin, residents of Greece and Cyprus. Subjects were recruited during a range of Armenian cultural, athletic or charitable events. The participants completed a version of the Post-Traumatic Stress Disorder (PTSD) (Self-Rating) Scale and a questionnaire including ad hoc questions regarding their relationship to the Armenian community, their attitudes and their source of information about the 1914—1918 events.

Results: Over a third (35.7%) of participants presented at least sub-clinical forms of such reactions during long periods of their lives. Women, older people, participants with a close relative lost during the events and those with strong connections to the Armenian community were more vulnerable.

Conclusion: The results are indicative of a long-lasting (though gradually fading) cross-generational traumatizing effect of the discussed events. Clinicians having to deal with patients belonging to cultural or ethnic groups that suffered persecutions in the past should take into account the probable effects caused by a trauma-transmission mechanism.
Community and Health Professionals’ Attitude Toward Depression: a Pilot Study in Nine Eaad Countries
Authors: Scheerder Gert , Van Audenhove Chantal , Arensman Ella , Bernik Barbara , Giupponi Giancarlo , Horel Anne-Claire , Maxwell Margaret , Sisask Merike , Szekely Andras , Värnik Airi , Hegerl Ulrich
Published: March 2010

Background: Community facilitators (CFs), such as pharmacists, policemen, teachers and clergy, may be an important community resource for patients with depression in addition to (mental) health professionals. However, they are ill prepared for such a role and little is known about their attitudes toward depression, which may affect practice.

Aim: To investigate CFs’ attitudes toward depression and compare them to those of (mental) health professionals and nurses.

Method: Attitudes were assessed in participants ( n = 2,670) of training programmes about depression in nine countries of the European Alliance Against Depression (EAAD). The EAAD questionnaire included attitudes toward depression and its treatment, perceived causes, preferred treatment options, and knowledge of depression symptoms.

Results: CFs and nurses had a more negative attitude toward patients with depression and toward antidepressants, and more limited knowledge of depression symptoms than (mental) health professionals. CFs more frequently supported non-standard treatment for depression. Nurse assistants clearly differed from registered nurses with their attitudes being among the least favourable and their knowledge the most limited of all groups.

Conclusions: CFs and nurses had less favourable attitudes and more limited knowledge regarding depression when compared to mental health professionals and doctors. This may negatively affect professional collaboration, challenge optimal treatment and stigmatize patients. CFs’ and nurses’ knowledge and attitudes may be similar to those of the general population and be related to a lack of training in mental health issues.
Effects of Computer-Assisted Instruction on Students’ Knowledge of the Self-Determined Learning Model of Instruction and Disruptive Behavior
Authors: Mazzotti Valerie L. , Wood Charles L. , Test David W. , Fowler Catherine H.
Published: March 2010

Instruction about goal setting can increase students’ self-determination and reduce problem behavior. Computer-assisted instruction could offer teachers another format for teaching goal setting and self-determination. This study used a multiple probes across participants design to examine the effects of computer-assisted instruction on students’ knowledge of the Self-Determined Learning Model of Instruction (SDLMI) and level of disruptive behavior. Results indicated increased knowledge of the SDLMI and decreased levels of disruptive behavior for all participants. Implications for future research and practice are discussed.
Individual and Structural Orientations in Socially Just Teaching: Conceptualization, Implementation, and Collaborative Effort
Authors: Chubbuck Sharon M.
Published: March 2010

This essay, drawn from theory, research, and the author’s practitioner research as a teacher educator, proposes a framework to inform teacher educators’ conceptualization and implementation of socially just teaching. The framework suggests that building on dispositions of fairness and the belief that all children can learn, a socially just teacher will engage in professional reflection and judgment using both an individual and a structural orientation to analyze the students’ academic difficulties and determine the cause and the solution to those difficulties, realizing that both individual and structural realities affect students’ learning. The essay then suggests how this individual and structural framework can inform the content and teaching strategies teacher educators use to instruct preservice teachers in socially just education. Finally, recommendations for research and dialogue in the teacher education community are suggested.
Carbon and Glass Fibers Modified by Polysilazane Based Thermal Resistant Coating
Authors: Shayed M.A. , Cherif Ch. , Hund R.D. , Cheng T. , Osterod F.
Published: March 2010

Thermal resistant coatings of textile materials are required so that they can fulfill the high security demands in the case of resistance to fire. These coatings also improve the properties of textiles as composite materials. In this research work, a polysilazane based coating was applied on carbon filament (CF) and glass filament (GF) rovings by a padding method. Tensile testing under thermal stress was carried out to assess the thermomechanical properties of both coated and uncoated rovings. Scanning electron microscopy, energy dispersive X-ray analysis, contact angle measurements, and surface energy calculations were performed to evaluate the surface properties of coated and uncoated rovings. The amount of coating mass on rovings was also determined using different recipes. Thermo-gravimetric analysis and weight loss after thermal treatment of coated and uncoated CF rovings were carried out to observe the oxidation behavior, as well as the thermal stability. The obtained testing results were assessed to ascertain the coating performances on GF and CF rovings.
Theoretical Study of a Spinning Triangle with Its Application in a Modified Ring Spinning System
Authors: Jie Feng  , Bin Gang Xu  , Xiao Ming Tao  , Tao Hua
Published: March 2010

The spinning triangle is a critical area in the spinning process of staple yarns. Its geometry influences the distribution of fiber tension in the spinning triangle and the properties of spun yarns. In earlier theoretical models, the spinning tension of the yarn acting on the convergence point is assumed to be perpendicular to the nip line of front rollers. This assumption is reasonable in the study of the conventional ring spinning triangle, but may not be appropriate for modified ring spinning systems in which the yarn spinning tension has an obvious angle with the vertical axis perpendicular to the nip line. Thus in this paper a new theoretical model is proposed by considering the inclination angle of the spinning tension. Based on the principle of minimum potential energy, the theoretical model quantitatively describes the fiber tension distribution and its relationships with the spinning parameters, shape of the spinning triangle and the inclination angle of yarn spinning tension. As an application of the proposed method, spinning triangles of a modified ring spinning system were investigated under various spinning parameters. The fiber tension distributions in the spinning triangle both with and without fiber buckling were numerically simulated and the results were compared with those from our earlier model. In addition, the properties of spun yarns produced by the modified system were evaluated and analyzed.
The Effect of Fiber Properties on the Characteristics of Spliced Yarns: Part II: Prediction of Retained Spliced Diameter
Authors: Ünal Pelin Gürkan , Arikan Cihat , Özdil Nilgün , Taşkin Cankut
Published: March 2010

The objective of the second part of the study is to investigate the retained spliced diameter with regard to splicing parameters and fiber and yarn properties. In order to analyze the effects of the fiber and yarn properties on the retained spliced diameter of ring spun cotton yarns, the yarns were produced from eight different cotton types in three yarn counts (29.5, 19.7 and 14.8 tex) and three different twist coefficients (αtex 3653, α tex 4038, αtex 4423). To investigate the effects of splicing parameters on the retained spliced diameter, opening air pressure, splicing air pressure and splicing air time were set according to an orthogonal experimental design. The retained spliced diameter was calculated and predicted by using an artificial neural network (ANN) and response surface methods. Analyses showed that ANN models are more powerful compared with response surface models in predicting the retained spliced diameter of ring spun cotton yarns.
Antistatic Property of Polyacrylonitrile Fiber by Plasma-grafting Treatment
Authors: Gang Bai  , Yanchun Liu
Published: March 2010

Hydrophilic monomer was grafted onto polyacrylonitrile fiber using an atmospheric pressure dielectric barrier discharge plasma technique. The degree of grafting was evaluated using a dyeing method. The treated surfaces were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The plasma-grafting treatment was found to introduce some amide, carboxyl and hyamine groups onto the fiber surface, and to drastically improve the wettability and antistatic ability of polyacrylonitrile fibers.
Resiliency and Optimism: An African American Senior Citizen’s Perspective
Authors: Baldwin Debora R. , Jackson David , Okoh Ife , Cannon Rex L.
Published: March 2010

A total of 52 African American senior citizens (aged 59-99 years) were asked to participate in a study examining psychological resources (ego resilience and dispositional optimism) and the experience of racial stress as a function of geographical location (north vs. south). This is an understudied population, and African American seniors who remain relatively active within their respected communities may provide useful information regarding these psychological constructs in particular and successful aging in general. Participants completed the ego resilience, optimism, stress, and distress surveys. When collapsed across geographical location, resilience was negatively correlated with distress and positively correlated with optimism. Dispositional optimism was negatively correlated with levels of psychological distress. African American seniors who resided in the north reported significantly less distress than those in the south. Findings support resiliency and optimism as stress buffers for older African Americans.
Review Essays: Who’s Afraid of Financial Markets?
Authors: Arminen Ilkka
Published: March 2010

There has recently been an upsurge in social studies of finance, which maintain that economics performs, shapes and formats the economy, and consider the formation and functioning of economic markets. They address market activities as global microstructures that are situated, reflexive accomplishments, focusing on the way in which the models, theories, procedures and techniques shape them. In all, financial sociology can attend to the interplay between actors’ cognitive states and the enactment of financial models as situated, historical processes. This promises to develop a broader social scientific account of financial markets as sequentially achieved global socio-material actions.
Sports Activity After Total Hip Resurfacing
Authors: Banerjee Marc , Bouillon Bertil , Banerjee Carolin , Bäthis Holger , Lefering Rolf , Nardini Miriam , Schmidt Joachim
Published: March 2010

Background: Little is known about sports activity after total hip resurfacing.

Hypothesis: Patients undergoing total hip resurfacing can have a high level of sports activity.

Study Design: Case series; Level of evidence, 4.

Methods: The authors evaluated the level of sports activities with a standardized questionnaire in 138 consecutive patients (152 hips) 2 years after total hip resurfacing. Range of motion, Harris hip score, and Oxford score were assessed, and radiological analysis was performed.

Results: Preoperatively, 98% of all patients participated in sports activities. Two years postoperatively, 98% of the patients participated in at least 1 sports activity. The level of sports activity decreased after surgery. The number of sports activities per patient decreased from 3.6 preoperatively to 3.2 postoperatively. Intermediate- and high-impact sports, especially tennis, soccer, jogging, squash, and volleyball, showed a significant decrease while the low-impact sports (stationary cycling, Nordic walking, and fitness/weight training) showed a significant increase. Physical activity level at the time of follow-up as measured by the Grimby scale was significantly higher than in the year before surgery. Duration of sports participation per week increased significantly after surgery. Men had a significantly higher sport level than women before and after surgery. Eighty-two percent felt no restriction while performing sports. One-third missed certain sports activities such as jogging, soccer, tennis, and downhill skiing. The Harris hip and Oxford scores showed a significant increase postoperatively.

Conclusion: The results of this short-term follow-up study show that sports activity after total hip resurfacing surgery is still possible. Physical activity level increased with a shift toward low-impact sports. Duration of sports participation increased. High-impact sports activities decreased. These findings can be important for the decision-making process for hip surgery and should be communicated to the patient.
Educating Reflective Practitioners: Learning to Embrace the Unexpected through Service Learning
Authors: Sletto Bjørn
Published: March 2010

Service learning projects are characterized by complex processes of knowledge production, which are contingent on narratives that inform the identities of educators, students, and community members. By encouraging students to critically reflect on their positionality and the social processes that inform such coproduction of knowledge, educators can use service learning to educate reflective practitioners capable of working productively with multiple actors. In a service learning course focusing on environmental justice at the University of Texas at Austin, students worked with a variety of community partners to document children’s knowledge of environmental hazards, reflecting critically on unexpected challenges during their fieldwork.