bluuebunny/crossref_metadata_2025 huggingface dataset:
Undercarboxylated Osteocalcin Is a Biomarker of Carotid Calcification in Patients with Essential Hypertension
Authors: Okura Takafumi , Kurata Mie , Enomoto Daijiro , Jotoku Masanori , Nagao Tomoaki , Desilva Veena Rasika , Irita Jun , Miyoshi Ken-Ichi , Higaki Jitsuo
Published: March 2010

The development of vascular calcification is an active, highly regulated process with similarities to bone formation. Osteocalcin (OC), a vitamin K-dependent protein expressed by osteoblasts, contains 3 γ-carboxyglutamic acid residues derived from the vitamin K-dependent posttranslational modification of glutamic acid residues. Circulating undercarboxylated OC (ucOC) is increased in vitamin K deficiency and serum ucOC is reported to be a clinical marker of vitamin K status. Vitamin K deficiency is associated with vascular calcification as well as osteoporosis. We evaluated the relationship between ucOC and carotid artery calcification in 92 patients with essential hypertension. Ultrasound of the common carotid artery was performed to identify vascular calcification and subjects were divided into 2 groups: a calcification (+) group and a calcification (–) group. Serum creatinine and ucOC levels were higher in the calcification (+) group than in the calcification (–) group and serum ucOC correlated with serum creatinine. To identify the independent determinant factor for carotid artery calcification, we applied both ucOC and estimated glomerular filtration rate as independent factors in logistic regression analysis. Serum ucOC was an independent determinant of carotid calcification, suggesting that circulating ucOC may be an important biomarker of carotid artery calcification.
Amiodarone Versus Procainamide for the Acute Treatment of Recurrent Supraventricular Tachycardia in Pediatric Patients
Authors: Chang Philip M. , Silka Michael J. , Moromisato David Y. , Bar-Cohen Yaniv
Published: March 2010

Background—

Intravenous amiodarone and procainamide are both used as therapies for refractory supraventricular tachycardia (SVT). However, no studies have compared the efficacy and safety of these agents in pediatric patients.

Methods and Results—

All patients treated with intravenous amiodarone or procainamide during 25 consecutive months for the following mechanisms of SVT were included: orthodromic reciprocating tachycardia, intra-atrial reentrant tachycardia, and ectopic atrial tachycardia; junctional ectopic tachycardia was excluded. Treatment response was categorized as full success, partial success, or failure. Partial success was defined as clinical improvement and/or arrhythmia control but not meeting full success criteria. Adverse events were classified as major (requiring resuscitation) or minor (management changes). There were 40 episodes of SVT in 37 patients (median age, 34 days; 24 with congenital heart disease). Amiodarone was the initial therapy in 26 cases and procainamide in 14 cases. If partial and full success are combined, procainamide was successful in 71% of cases compared with 34% for amiodarone (
P
=0.046). If partial success is considered a treatment failure, procainamide was successful in 50% compared with 15% for amiodarone (
P
=0.029). Ten patients received the second medication after the first failed. Success was achieved in 5 of 8 amiodarone-to-procainamide crossovers compared with 1 of 2 procainamide-to-amiodarone crossovers. One major and 10 minor adverse events occurred in amiodarone patients versus 6 minor adverse events in procainamide patients (
P
=NS).

Conclusions—

In this cohort, procainamide achieved greater success compared with amiodarone in the management of recurrent SVT without statistically significant differences in adverse event frequency.
Long-Term Outcome After Ablative Therapy of Postoperative Atrial Tachyarrhythmia in Patients With Congenital Heart Disease and Characteristics of Atrial Tachyarrhythmia Recurrences
Authors: de Groot Natasja M.S. , Atary Jael Z. , Blom Nico A. , Schalij Martin J.
Published: March 2010

Background—

Catheter ablation has evolved as a possible curative treatment modality for atrial tachyarrhythmia (AT) in patients with congenital heart defects (CHD). However, data on long-term outcome are scarce. We examined characteristics of recurrent AT after ablation of postoperative AT during long-term follow-up in CHD patients.

Methods and Results—

CHD patients (n=53; 27 men; age, 38�15 years) referred for catheter ablation of AT were studied during a follow-up period of 5�3 years. After ablative therapy of the first AT (n=53, 27 atrial flutter, cycle length=288�81 ms; 22 intra-atrial reentrant tachycardia, cycle length=309�81 ms; 5 focal atrial tachycardia, cycle length=380�147 ms; success rate, 65%), AT recurred (59% within the first year) in 29 patients; 15 underwent repetitive ablative therapy. Mechanisms underlying recurrent AT were similar in 7 patients (intra-atrial reentrant tachycardia, 2; atrial flutter, 5). The location of arrhythmogenic substrates of recurrent AT (intra-atrial reentrant tachycardia, focal atrial tachycardia) was different for all but 1 patient. After 5�3 years, 5 patients died of heart failure, 3 were lost to follow-up, and the remaining patients had sinus rhythm (n=31), AT (n=5), or atrial flutter (n=14). Antiarrhythmic drugs were used by 18 (57%) sinus rhythm patients.

Conclusions—

Successive postoperative AT in CHD patients developing over time may be caused by different mechanisms, including focal and reentrant mechanisms. Recurrent AT originated from different locations, suggesting that these new AT were not caused by arrhythmogenicity of previous ablative lesions. Long-term outcome is often complicated by development of atrial fibrillation. Despite frequent need for repeat ablative therapy, most patients are in sinus rhythm.
Damage to the Esophagus After Atrial Fibrillation Ablation
Authors: Zellerhoff Stephan , Ullerich Hansjörg , Lenze Frank , Meister Tobias , Wasmer Kristina , Mönnig Gerold , Köbe Julia , Milberg Peter , Bittner Alex , Domschke Wolfram , Breithardt Günter , Eckardt Lars
Published: March 2010

Background—

Radiofrequency catheter ablation is increasingly used in the treatment of atrial fibrillation. Esophageal wall changes varying from erythema to ulcers have been described by endoscopy in up to 47% of patients following pulmonary vein isolation (PVI). Although esophageal changes are frequently reported, the development of a left atrial (LA)-esophageal fistula is fortunately rare. Nevertheless, mucosal changes may just represent “the tip of the iceberg.” The aim of this study was, therefore, to investigate the more subtle changes of and injuries to the posterior wall of the LA, the periesophageal and mediastinal connective tissue, and the whole wall of the esophagus, including mucosal changes by esophagogastroduodenoscopy (EGD) combined with radial endosonography (EUS).

Methods and Results—

Twenty-nine patients (7 females; mean age, 57.7�10.5 years [range, 23–75 years]) underwent EGD and EUS before and after PVI within 48 hours. PVI was performed as a circumferential antral isolation of the septal and lateral pulmonary veins guided by a decapolar circular mapping catheter using a 3-dimensional mapping system with the integration of a preprocedurally acquired computed tomography scan of the left atrium. The maximum power applied was 30 W, with an open-irrigated catheter using a maximum flow rate of 30 mL/min. In all patients, the esophagus was reconstructed using the same computed tomography scan and displayed during the ablation procedure. In case of newly detected periesophageal changes, EGD and EUS were repeated 1 week after the PVI. In all patients, a regular contact area between the LA and the esophagus could be demonstrated before PVI. The mean vertical contact length was 4.4�1.5 cm (range, 2–10 cm); and the mean distance between the anterior wall of the esophagus and the endocardium was 2.6�0.8 mm (range, 1.4–4.0 mm). After PVI, morphological changes of the periesophageal connective tissue and the posterior wall of the LA were diagnosed by endosonography in 8 patients (27%; 95% confidence interval, 12.73–47.24). No mucosal changes of the esophagus in terms of erythema or ulcers were found. In all but one patient (who refused the control), all periesophageal and atrial changes had resolved within 1 week. No atrioesophageal fistula occurred during follow-up (mean follow-up, 294�110 days [range, 36–431 days]).

Conclusions—

Mucosal changes of the esophagus after PVI-like ulcers or erythema could not be demonstrated, yet structural changes of the mediastinum, which were only visible by endosonography, occurred in 27% of patients in the present study. This may indicate a higher than expected periesophageal injury because of PV ablation. Endosonography might prove to be a sensitive and reliable tool in the follow-up after PVI.
Effects of Mitral Valve Surgery on Myocardial Energetics in Patients With Severe Mitral Regurgitation
Authors: Chow Benjamin J.W. , Abunassar Joseph G. , Ascah Kathryn , deKemp Robert , DaSilva Jean , Mesana Thierry , Beanlands Rob S. , Ruddy Terrence D.
Published: March 2010

Background—

Hemodynamically significant mitral regurgitation (MR) may alter left ventricular (LV) myocardial energy requirements. The effects of MR and subsequent corrective mitral valve (MV) surgery on myocardial energetics are not well understood. A better understanding of myocardial energetics and the LV responses to changes in preload and afterload may assist with the understanding of mitral regurgitation and its effect on the LV. We sought to determine the effects of MV surgery on forward stroke work, myocardial oxidative metabolism, and myocardial efficiency.

Methods and Results—

Prospectively enrolled patients with chronic, severe, nonischemic mitral regurgitation underwent echocardiography, radionuclide angiography, and C-11 acetate positron emission tomography to measure LV volumes, ejection fraction, and oxidative metabolism before and 1 year after MV surgery. Forward and total stroke work corrected for oxidative metabolism was used to estimate efficiency using the work metabolic index. Fourteen patients (age, 59� 8 years) with myxomatous MV were enrolled. One year after MV surgery, there was a reduction in LV end-diastolic and end-systolic volumes (231�86 to 131�21 mL;
P
<0.01 and 98�53 to 55�17 mL;
P
<0.01). Forward stroke volume increased (58.1�15.0 to 75.5�23 mL;
P
<0.01), LV ejection fraction was preserved without a significant change in oxidative metabolism. Forward work metabolic index improved (4.99�1.32�10
6
to 6.59�2.45�10
6
mm Hg�mL/m
2
;
P
=0.02). This was not at the expense of total work metabolic index, which was preserved.

Conclusions—

MV surgery has a beneficial effect on forward stroke volume and forward work metabolic index without adverse effects on oxidative metabolism or total work metabolic index.
Relationship Between Coronary Microvascular Dysfunction and Cardiac Energetics Impairment in Type 1 Diabetes Mellitus
Authors: Shivu G. Nallur , Phan T.T. , Abozguia K. , Ahmed I. , Wagenmakers A. , Henning A. , Narendran P. , Stevens M. , Frenneaux M.
Published: March 2010

Background—

Asymptomatic subjects with diabetes mellitus have an impaired cardiac energetics status that may play a significant role in the development of heart failure. In the present study, we assessed the role of microvascular dysfunction in the development of impaired cardiac energetics in subjects with type 1 diabetes mellitus.

Methods and Results—

Twenty-five asymptomatic subjects with type 1 diabetes mellitus (mean age ±1 SD 33±8 years) and 26 age-, sex-, and body mass index–matched healthy control subjects (32±8 years old) were recruited into the study. The type 1 diabetes mellitus subjects were divided into 2 age-matched groups (newly diagnosed [<5 years] and longer-duration [>10 years] diabetes) to assess the impact of microvascular disease. All subjects had an echocardiogram and an exercise ECG performed, followed by magnetic resonance spectroscopy and stress magnetic resonance imaging. Compared with healthy control subjects, the phosphocreatine/γ-ATP ratio was reduced significantly both in subjects with longer-term (2.1±0.5 versus 1.5±0.4,
P
<0.000) and newly diagnosed (2.1±0.5 versus 1.6±0.2,
P
<0.000) diabetes. The phosphocreatine/γ-ATP ratio was similar in newly diagnosed diabetes subjects and those with longer-term disease (1.6±0.2 versus 1.5±0.4,
P
=0.32). The mean myocardial perfusion reserve index in the longer-term type 1 diabetes mellitus subjects was significantly lower than in healthy control subjects (1.7±0.6 versus 2.3±0.4,
P
=0.005). On univariate analysis, there was no significant correlation of phosphocreatine/γ-ATP ratio with myocardial perfusion reserve index (
r
=0.21,
P
=0.26).

Conclusions—

We demonstrate that young subjects with uncomplicated type 1 diabetes mellitus have impaired myocardial energetics irrespective of the duration of diabetes and that the impaired cardiac energetics status is independent of coronary microvascular function. We postulate that impairment of cardiac energetics in these subjects primarily results from metabolic dysfunction rather than microvascular impairment.
Randomized Trial of Simple Versus Complex Drug-Eluting Stenting for Bifurcation Lesions
Authors: Hildick-Smith David , de Belder Adam J. , Cooter Nina , Curzen Nicholas P. , Clayton Tim C. , Oldroyd Keith G. , Bennett Lorraine , Holmberg Steve , Cotton James M. , Glennon Peter E. , Thomas Martyn R. , MacCarthy Philip A. , Baumbach Andreas , Mulvihill Niall T. , Henderson Robert A. , Redwood Simon R. , Starkey Ian R. , Stables Rodney H.
Published: March 2010

Background—

The optimal strategy for treating coronary bifurcation lesions remains a subject of debate. With bare-metal stents, single-stent approaches appear to be superior to systematic 2-stent strategies. Drug-eluting stents, however, have low rates of restenosis and might offer improved outcomes with complex stenting techniques.

Methods and Results—

Patients with significant coronary bifurcation lesions were randomized to either a simple or complex stenting strategy with drug-eluting stents. In the simple strategy, the main vessel was stented, followed by optional kissing balloon dilatation/T-stent. In the complex strategy, both vessels were systematically stented (culotte or crush techniques) with mandatory kissing balloon dilatation. Five hundred patients 64±10 years old were randomized; 77% were male. Eighty-two percent of lesions were true bifurcations (>50% narrowing in both vessels). In the simple group (n=250), 66 patients (26%) had kissing balloons in addition to main-vessel stenting, and 7 (3%) had T stenting. In the complex group (n=250), 89% of culotte (n=75) and 72% of crush (n=169) cases were completed successfully with final kissing balloon inflations. The primary end point (a composite at 9 months of death, myocardial infarction, and target-vessel failure) occurred in 8.0% of the simple group versus 15.2% of the complex group (hazard ratio 2.02, 95% confidence interval 1.17 to 3.47,
P
=0.009). Myocardial infarction occurred in 3.6% versus 11.2%, respectively (
P
=0.001), and in-hospital major adverse cardiovascular events occurred in 2.0% versus 8.0% (
P
=0.002), respectively. Procedure duration and x-ray dose favored the simple approach.

Conclusions—

When coronary bifurcation lesions are treated, a systematic 2-stent technique results in higher rates of in-hospital and 9-month major adverse cardiovascular events. This difference is largely driven by periprocedural myocardial infarction. Procedure duration is longer, and x-ray dose is higher. The provisional technique should remain the preferred strategy in the majority of cases.

Clinical Trial Registration Information—

URL: http://www.clinicaltrials.gov. Unique identifier: NCT 00351260.
Exposure to a High-Fat Diet Alters Leptin Sensitivity and Elevates Renal Sympathetic Nerve Activity and Arterial Pressure in Rabbits
Authors: Prior Larissa J. , Eikelis Nina , Armitage James A. , Davern Pamela J. , Burke Sandra L. , Montani Jean-Pierre , Barzel Benjamin , Head Geoffrey A.
Published: March 2010

The activation of the sympathetic nervous system through the central actions of the adipokine leptin has been suggested as a major mechanism by which obesity contributes to the development of hypertension. However, direct evidence for elevated sympathetic activity in obesity has been limited to muscle. The present study examined the renal sympathetic nerve activity and cardiovascular effects of a high-fat diet (HFD), as well as the changes in the sensitivity to intracerebroventricular leptin. New Zealand white rabbits fed a 13.5% HFD for 4 weeks showed modest weight gain but a 2- to 3-fold greater accumulation of visceral fat compared with control rabbits. Mean arterial pressure, heart rate, and plasma norepinephrine concentration increased by 8%, 26%, and 87%, respectively (
P
<0.05), after 3 weeks of HFD. Renal sympathetic nerve activity was 48% higher (
P
<0.05) in HFD compared with control diet rabbits and was correlated to plasma leptin (
r
=0.87;
P
<0.01). Intracerebroventricular leptin administration (5 to 100 μg) increased mean arterial pressure similarly in both groups, but renal sympathetic nerve activity increased more in HFD-fed rabbits. By contrast, intracerebroventricular leptin produced less neurons expressing c-Fos in HFD compared with control rabbits in regions important for appetite and sympathetic actions of leptin (arcuate: −54%, paraventricular: −69%, and dorsomedial hypothalamus: −65%). These results suggest that visceral fat accumulation through consumption of a HFD leads to marked sympathetic activation, which is related to increased responsiveness to central sympathoexcitatory effects of leptin. The paradoxical reduction in hypothalamic neuronal activation by leptin suggests a marked “selective leptin resistance” in these animals.
Renal Medullary MicroRNAs in Dahl Salt-Sensitive Rats
Authors: Liu Yong , Taylor Norman E. , Lu Limin , Usa Kristie , Cowley Allen W. , Ferreri Nicholas R. , Yeo Nan Cher , Liang Mingyu
Published: March 2010

MicroRNAs are endogenous repressors of gene expression. We examined microRNAs in the renal medulla of Dahl salt-sensitive rats and consomic SS-13
BN
rats. Salt-induced hypertension and renal injury in Dahl salt-sensitive rats, particularly medullary interstitial fibrosis, have been shown previously to be substantially attenuated in SS-13
BN
rats. Of 377 microRNAs examined, 5 were found to be differentially expressed between Dahl salt-sensitive rats and consomic SS-13
BN
rats receiving a high-salt diet. Real-time PCR analysis demonstrated that high-salt diets induced substantial upregulation of miR-29b in the renal medulla of SS-13
BN
rats but not in SS rats. miR-29b was predicted to regulate 20 collagen genes, matrix metalloproteinase 2 (
Mmp2
), integrin β1 (
Itgb1
), and other genes related to the extracellular matrix. Expression of 9 collagen genes and
Mmp2
was upregulated by a high-salt diet in the renal medulla of SS rats, but not in SS-13
BN
rats, an expression pattern opposite to miR-29b. Knockdown of miR-29b in the kidneys of SS-13
BN
rats resulted in upregulation of several collagen genes. miR-29b reduced expression levels of several collagen genes and
Itgb1
in cultured rat renal medullary epithelial cells. Moreover, miR-29b suppressed the activity of luciferase when the reporter gene was linked to a 3′-untranslated segment of collagen genes
Col1a1
,
Col3a1
,
Col4a1
,
Col5a1
,
Col5a2
,
Col5a3
,
Col7a1
,
Col8a1
,
Mmp2
, or
Itgb1
but not
Col12a1
. The result demonstrated broad effects of miR-29b on a large number of collagens and genes related to the extracellular matrix and suggested involvement of miR-29b in the protection from renal medullary injury in SS-13
BN
rats.
Myogenic Responses of Mouse Isolated Perfused Renal Afferent Arterioles
Authors: Lai En Yin , Onozato Maristela L. , Solis Glenn , Aslam Shakil , Welch William J. , Wilcox Christopher S.
Published: March 2010

Because defects in renal autoregulation may contribute to renal barotrauma in chronic kidney disease, we tested the hypothesis that the myogenic response is diminished by reduced renal mass. Kidneys from 5/6 nephrectomized mice had only a minor increase in the glomerular sclerosis index. The telemetric mean arterial pressure (108±10 mm Hg) was unaffected after 3 months of high-salt intake (6% salt in chow) or reduced renal mass. Afferent arterioles from 5/6 nephrectomized mice and sham-operated controls were perfused ex vivo during step changes in pressure from 40 to 134 mm Hg. Afferent arterioles developed a constriction and a linear increase in active wall tension above a perfusion pressure of 36±6 mm Hg, without a plateau. The slope of active wall tension versus perfusion pressure defined the myogenic response, which was similar in sham mice fed normal or high-salt diets for 3 months (2.90±0.22 versus 3.22±0.40 dynes · cm
−1
/mm Hg;
P
value not significant). The myogenic response was unaffected after 3 days of reduced renal mass on either salt diet (3.39±0.61 versus 4.04±0.47 dynes · cm
−1
/mm Hg) but was reduced (
P
<0.05) in afferent arterioles from reduced renal mass groups fed normal and high salt at 3 months (2.10±0.28 and 1.35±0.21 dynes · cm
−1
/mm Hg). In conclusion, mouse renal afferent arterioles develop a linear increase in myogenic tone around the range of ambient perfusion pressures. This myogenic response is impaired substantially in the mouse model of prolonged reduced renal mass, especially during high salt intake.
Why Respecting Physical Integrity Rights Reduces Terrorism
Authors: Walsh James I. , Piazza James A.
Published: March 2010

Does respect for human rights check or promote terrorism? This question is hotly debated within policy circles. Some hold that restricting human rights is a necessary if unfortunate cost of preventing terrorism. Others conclude that such abuses aggravate political grievances that contribute to terror. The authors demonstrate that theory and data support the latter position. They hypothesize that abuse of the subset of rights known as physical integrity rights fuels terrorism by making it more difficult for government authorities to collect intelligence on terrorists and by undermining domestic and international support for their counterterrorism efforts. They test this hypothesis using a data set that includes measures of both domestic and transnational terrorist attacks and find that respect for physical integrity rights is consistently associated with fewer terrorist attacks. This suggests that those interested in curtailing terrorism should press governments to more carefully respect physical integrity rights.
Self-Controlled Concurrent Feedback Facilitates the Learning of the Final Approach Phase in a Fixed-Base Flight Simulator
Authors: Huet Michaël , Jacobs David M. , Camachon Cyril , Goulon Cedric , Montagne Gilles
Published: March 2010

Objective: This study (a) compares the effectiveness of different types of feedback for novices who learn to land a virtual aircraft in a fixed-base flight simulator and (b) analyzes the informational variables that learners come to use after practice. Background: An extensive body of research exists concerning the informational variables that allow successful landing. In contrast, few studies have examined how the attention of pilots can be directed toward these sources of information. Method: In this study, 15 participants were asked to land a virtual Cessna 172 on 245 trials while trying to follow the glide-slope area as accurately as possible. Three groups of participants practiced under different feedback conditions: with self-controlled concurrent feedback (the self-controlled group), with imposed concurrent feedback (the yoked group), or without concurrent feedback (the control group). Results: The self-controlled group outperformed the yoked group, which in turn outperformed the control group. Removing or manipulating specific sources of information during transfer tests had different effects for different individuals. However, removing the cockpit from the visual scene had a detrimental effect on the performance of the majority of the participants. Conclusion: Self-controlled concurrent feedback helps learners to more quickly attune to the informational variables that allow them to control the aircraft during the approach phase. Applications: Knowledge concerning feedback schedules can be used for the design of optimal practice methods for student pilots, and knowledge about the informational variables used by expert performers has implications for the design of cockpits and runways that facilitate the detection of these variables.
Glove Attributes and Their Contribution to Force Decrement and Increased Effort in Power Grip
Authors: Willms Kirsten , Wells Richard , Carnahan Heather
Published: March 2010

Objective: To determine the contribution of the loss of tactile sensitivity, glove flexibility, glove thickness, and changes in finger geometry to force decrement and increased effort during gloved power grip. Background: Gloved work has been shown to increase the effort required to perform manual tasks. Method: A battery of maximal and submaximal gripping tasks was performed while grip force and surface electromyography of seven forearm muscles were recorded. Participants performed power grips while wearing three different thicknesses of rubber gloves (differing only in thickness; maximum 3.1 mm), wearing interdigital spacers between the fingers (matched to the glove thicknesses), and with a bare hand. Results: Decreases in maximum grip force compared with the bare hand were observed for the thickest glove (—31.0 ± 6.8%, p < .05) and for the thickest interdigital spacers (—9.7 ± 5.9 %, p < .05). Participants increased their grip force with increasing glove thickness for a submaximal object-lifting task ( p < .01). To maintain an unloaded grip posture and to create a fixed submaximal force, participants increased muscle activation ( p < .05) for all muscles with increasing glove thickness. Conclusion: Decreases in maximal grip force and increased effort in submaximal tasks could be attributed to a combination of reduced tactile sensitivity, the effort to bend the gloves, and interdigital separation. Application: Although the values obtained are specific to the rubber gloves tested, the results give insights into factors important in the design and selection of gloves.
Understanding the Different Realities, Experience, and Use of Self-Esteem Between Black and White Adolescent Girls
Authors: Adams Portia E.
Published: March 2010

African American adolescent females possess higher self-esteem than any other racial or ethnic adolescent female group. This article tests two popular empirically supported explanations for Black high self-esteem: contingency of self-esteem theory and the locus of control model. This article builds on past research to illustrate the specific mechanisms of self-esteem for Black and White adolescent girls. To facilitate an investigation of these theories, self-esteem was explored as a bidimensional construct consisting of self-worth and self-deprecation. The sample consisted of 453 Black and 1,902 White adolescent females. Multivariate regression analyses produced the following outcomes: The contingency of self-esteem theory and the locus of control model were not supported. A significant race by social support interaction found that even in low support situations Black adolescent females reported less self-deprecation than White females.
Generational Differences in Work Values: Leisure and Extrinsic Values Increasing, Social and Intrinsic Values Decreasing
Authors: Twenge Jean M. , Campbell Stacy M. , Hoffman Brian J. , Lance Charles E.
Published: March 2010

Organizations are currently facing the retirement of many older workers and the challenge of recruiting and retaining young talent. However, few studies have empirically substantiated generational differences in work values. This study examines the work values of a nationally representative sample of U.S. high school seniors in 1976, 1991, and 2006 (N = 16,507) representing Baby Boomers, Generation X (GenX), and Generation Me (GenMe, also known as GenY, or Millennials). With data collected across time, these analyses isolate generational differences from age differences, unlike one-time studies, which cannot separate the two. Leisure values increased steadily over the generations (d comparing Boomers and GenMe = .57), and work centrality declined. Extrinsic values (e.g., status, money) peaked with GenX but were still higher among GenMe than among Boomers (d = .26). Contrary to popular press reports, GenMe does not favor altruistic work values (e.g., helping, societal worth) more than previous generations. Social values (e.g., making friends) and intrinsic values (e.g., an interesting, results-oriented job) were rated lower by GenMe than by Boomers. These findings have practical implications for the recruitment and management of the emerging workforce.
A Salutogenic Analysis of Healthy Aging in Active Elderly Persons
Authors: Wiesmann Ulrich , Hannich Hans-Joachim
Published: March 2010

The authors systematically explore relationships between generalized resistance resources (GRRs), the sense of coherence (SOC), and the healthease/dis-ease (HE-DE) continuum. A sample of 170 active older adults at the mean age of 67 years filled out a comprehensive questionnaire. The results indicate that 11 GRRs significantly predicted SOC (56% of variance accounted for) and that GRRs significantly predicted the HE-DE continuum (38%). Holding GRRs constant, SOC significantly accounted for 3% additional variance in health. Finally, SOC mediated GRRs’ effects on health. SOC proved to be a complete mediator for autonomy/identity resource gains, social external health locus of control, self-efficacy, and self-esteem, and a partial mediator for activity level and social support. The findings suggest that SOC plays a central role for health maintenance and health promotion in the third age because it pools resource influences on health. The authors recommend the application of salutogenic theory to intervention.
Preservation of endothelium nitric oxide release during beating heart surgery with respect to continuous flow cardiopulmonary bypass
Authors: Lanzarone Ettore , Gelmini Fabrizio , Fumero Andrea , Carini Marina , Costantino Maria Laura , Fumero Roberto , Alfieri Ottavio
Published: March 2010

A correlation between perfusion modality and vascular dilation induced by endothelial nitric oxide (NO) release has been pointed out in the literature; nevertheless, only a few studies deal with the analysis of patients treated by cardiac surgery. The aim of this work is to analyze endothelial NO release in patients undergoing cardiac surgery under continuous flow cardiopulmonary bypass (CPB) or pulsatile perfusion. Pulsatile devices approved for clinical CPB do not accurately reproduce the physiological flow waveform provided by the left ventricle while, on the other hand, it is important to analyze pulsatile perfusion under both physiological flow waveform and pulsatile flow CPB. Physiological pulsatile perfusion (supplied by the left ventricle) was examined in this study. A total of 16 patients undergoing cardiac surgery were enrolled in the study and divided into two groups: 8 patients were put on continuous flow CPB while the others underwent beating heart surgery. Venous blood samples were withdrawn to quantify endothelial NO release through its bioactive forms in blood. Plasma was used for the chemiluminescent detection of nitrite (NO2—) and nitrate (NO3—), and the cellular component for electron spin resonance detection of nitrosylhemoglobin. Significant reduction in the intraoperative concentration with respect to the preoperative was observed only in the continuous group for both NO2— and NOx (NO2— + NO3—) concentration (p=0.003 and p=0.016, respectively). A significant difference in the intraoperative nitrite concentration was also observed between the groups (p=0.006). Nitrosylhemoglobin concentration, although not instrumentally detectable, resulted as negligible with respect to the other NO metabolites. Despite the small number of patients belonging to each group, this significant reduction of NO2— concentration under continuous flow CPB revealed a strong dependence on endothelial NO release and plasma nitrite concentration on perfusion modality.
Influence of Process Conditions on Tensile Properties Polyoxymethylene Composite
Authors: Hsu C.-I. , Hwang Jiun-Ren , Ting Ping-Huang
Published: March 2010

This study investigates the influence of process conditions on the tensile properties of polyoxymethylene (POM) composites that contain three amounts of glass fiber-reinforcement (0 wt%, 15 wt% and 25 wt%). Four processing parameters - orientation of fiber, thickness of fiber layer, amount of fiber, and injection molding parameter were considered. The morphology of the fiber layer is observed by scanning electron microscopy (SEM), to elucidate the correlation between the orientation of the fibers and the mechanism of fracture of the bucking surface. The experimental results show that the maximum ultimate stress is obtained at a filling time of 1.5 s, a melt temperature of 215°C, a mold temperature of 75°C, and a packing pressure 75 MPa. SEM revealed that the composite contained two distinct layers. The fibers in the frozen layer were parallel to the melt flow, while the fiber was perpendicular to the melt flow in the core layer. The thickness of the frozen layer increased with the amount of fiber, increasing tensile strength. Additionally, fiber pullout and across-matrix cracking are the main fracture mechanisms of the frozen layer, whereas failure of the fiber-matrix interface is the major fracture mechanism in the core layer.
Enhancement of Mechanical Properties of Composites through Incorporation of CNT in VARTM - A Review
Authors: Rachmadini Y. , Tan V.B.C. , Tay T.E.
Published: March 2010

Some issues and development in the vacuum-assisted resin transfer molding (VARTM) technique and the use of carbon nanotubes (CNT) as additional reinforcement in laminated composite are discussed in this article. There has been considerable interest in the incorporation of CNT as secondary reinforcement in addition to the primary fiber reinforcement in laminated composites. The use of CNT is apparently able to enhance the out-of-plane material properties by improving interlaminar strength and fracture toughness of laminated composites. The addition of CNT may be done through the VARTM technique, a non-autoclave, relatively low-cost method, frequently used to fabricate parts with complex shapes. This survey shows that while the matrix-dominated interlaminar fracture toughness and shear properties may be improved, the improvement in in-plane fiber-dominated properties is very modest.
Preparation of Unsaturated Polyester Liquid Natural Rubber Reinforced by Montmorillonite
Authors: Ahmad Ishak , Farihan Mohamed Hassan
Published: March 2010

The effect of liquid natural rubber (LNR) on the mechanical properties of unsaturated polyester (UP) has been studied in this article. Mechanical tests, such as impact and tensile test, have been conducted on the UP-LNR sample in order to determine the optimum LNR composition. The results showed that the tensile strength and impact energy increased with LNR and optimized at 10 phr. The optimum composition of LNR was used to prepare the composite with montmorillonite (MMT). X-ray diffraction of the composite showed the absence of peak in nanocomposites, which contain treated MMT. Scanning of electron microscopy also clearly showed that the agglomeration of clay occurs in the composite using untreated MMT, but is significantly reduced in size for the composite using treated MMT. On the other hand, the mechanical properties, such as tensile strength, tensile modulus, and impact energy, of the composites with modified MMT were also higher than the composite with unmodified MMT. The optimum composition of modified MMT in the composite was found at 4% filler loading.
Sub-LFL Flame Kernels in Flash Point Tests: A Reappraisal of the Observations
Authors: Jones J.C.
Published: March 2010

The Forum is intended to provide for dialogue and discussion among fire experts, scientists and consultants. Contributions to The Forum will not be refereed in the conventional sense, but will be subject to review by the Editor or a member of the Journal’s Editorial Board relative to appropriateness, clarity, timeliness, and scope of interest. The Editor will be the sole judge of those contributions to be published. Opinions expressed, however, are those of the authors and not of the Editor or Sage Publications, Ltd.
Studies on Fire Characteristics in Over- and Underventilated Full-scale Compartments
Authors: Hwang Cheol-Hong , Lock Andrew , Bundy Matthew , Johnsson Erik , Gwon Hyun Ko
Published: March 2010

An experimental study was conducted to investigate the thermal, chemical, and flow environments of heptane fires in an ISO 9705 room. Fuel flow rates and vent size were manipulated to create overventilated fire (OVF) and underventilated fire (UVF) conditions. Numerical simulations were also performed, for the same conditions, with the Fire Dynamics Simulator (FDS) developed at the National Institute of Standards and Technology. Both OVF and UVF conditions were characterized with temperature distributions, and combustion product formation measured locally in the upper layer, as well as combustion efficiency and global equivalence ratio. It was shown that the numerical results agree quantitatively with measurements in both OVF and UVF. The internal flow pattern rotated in the opposite direction for the UVF relative to the OVF so that a portion of products recirculated to the inside of compartment. This flow pattern may affect changes in the complex processes of CO and soot formation inside the compartment due to an increase in the residence time of high-temperature products. The 3D flow structures including O2 and CO distribution were visualized inside the underventilated compartment fire using FDS. It was observed that the two gas sample locations in the upper layer of the room were insufficient to completely characterize the internal structure of the compartment fire.
Two Cities, Five Industries: Similarities and Differences within and between Cultural Industries in New York and Los Angeles
Authors: Currid Elizabeth , Williams Sarah
Published: March 2010

Recent work has pointed towards the possibility that industries are not tied to their specific urban location as much as to their linkages with particular types of infrastructure and to their social and economic networks. Industries have similar clustering patterns even in very different cities. Using Bureau of Labor Statistics data, we conducted geographic information systems (GIS) analysis to compare cultural industries in Los Angeles and New York City, two cities with very different types of geography and urban environments. Two distinct findings emerged: (1) when cultural industries are disaggregated into distinct industrial subsectors (art, fashion, music, design), important differences among them emerge; and (2) cultural industries “behave” similarly in each city because their subsectors tend to colocate (e.g., art with design; music with film) in similar ways, and this colocation pattern remains consistent in both locations. Such notable clustering tendencies of cultural industries help inform future research and further enlighten our understanding of their location patterns.
“Some People Aren’t Cut Out for It”: The Role of Personality Factors in the Careers of Teachers of Students With EBD
Authors: Prather-Jones Bianca
Published: March 2010

This qualitative study explores reasons that experienced teachers of students with emotional and/or behavioral disorders give for remaining in their field. Previous research, usually conducted among the wider population of special education teachers, has focused on the relationship of employment and demographic factors to attrition and has primarily relied on quantitative surveys. The researcher sought to expand that body of work through the use of in-depth interviews with teachers who have continued teaching students with emotional and/or behavioral disorders for more than 6 years. In discussing career decisions, these teachers consistently pointed to the importance of personal characteristics, such as the fit between their personality and the demands of the job. These findings point to the importance of recruiting appropriate candidates for this field and helping pre- and in-service teachers develop the personal skills necessary to cope with the unique demands of the job.
Quantitative Synthesis and Component Analysis of Single-Participant Studies on the Picture Exchange Communication System
Authors: Tincani Matt , Devis Kathryn
Published: March 2010

The Picture Exchange Communication System (PECS) has emerged as the augmentative communication intervention of choice for individuals with autism spectrum disorder (ASD), with a supporting body of single-participant studies. This report describes a meta-analysis of 16 single-participant studies on PECS with percentage of nonoverlapping data (PND) as the metric of effect size. Results suggest that PECS was moderately effective in establishing mands (PND = 80.1) for 41 participants up to Phase IV of the system. Higher levels of manding were found when PECS was taught to individuals without ASD diagnoses versus those with ASD diagnoses and in single settings versus multiple settings; however, these differences were not statistically significant. For a smaller subset of participants for whom vocalizations were recorded, PECS appeared to facilitate speech, though considerable variability in speech acquisition was evident. While these results support PECS as an evidenced-based communication intervention, they indicate that more research is needed on speech with PECS, to establish the efficacy of PECS when implemented across settings and communicative partners, and to confirm efficacy of Phases IV, V, and VI.
Close Companions at Church, Health, and Health Care Use in Late Life
Authors: Krause Neal
Published: March 2010

Objective: This article studies whether there are age variations in the relationships between having a close companion friend at church, health, and outpatient physician visits. Method: The data come from two waves of interviews in a nationwide survey of older adults. These data are analyzed with ordinary least squares multiple regression analyses. Results: The findings reveal that older people who have a close companion friend in the place where they worship are more likely to rate their health in a favorable way over time. However, these health-related benefits emerge only among the oldest-old study participants. The data results further indicate that having a close friend at church is associated with fewer outpatient physician visits over time, but once again, the results are observed only among the oldest old. Discussion: The results from this study provide preliminary insight into one way in which spiraling health care costs may eventually be curtailed.
Physical Disability and Depression: Clarifying Racial/Ethnic Contrasts
Authors: Lewis Brown Robyn , Turner R. Jay
Published: March 2010

Objective: This study assesses racial/ethnic disparities in depressive symptoms among persons who are physically disabled and evaluates the extent to which variation in stress exposure, coping resources, and feelings of shame associated with disability account for observed differences. Method: Data are drawn from a Miami-Dade County study that oversampled persons with physical disabilities. The sample used in this study includes individuals of Cuban and other Hispanic heritage, African Americans, and non-Hispanic Whites who identify as physically disabled ( N = 550). Results: Cubans and other Hispanics report higher levels of depressive symptoms. This elevation in risk is largely explained by variations in stress exposure, available coping resources, and shame. Findings also suggest that feelings of shame may condition the relationships between both stress exposure and coping resources and depressive symptomatology. Discussion: Findings demonstrate racial/ethnic differences in depressive symptoms among persons with physical disabilities and highlight the importance of stress exposure, coping resources, and shame for understanding these differences.
Return Migration and the Health of Older Aged Parents: Evidence From Rural Thailand
Authors: Zimmer Zachary , Knodel John
Published: March 2010

Objective: To examine the extent to which an association exists between health of older parents and return migration of children in rural Thailand. Method: Data come from the 2006 Migration Impact Survey specifically designed to obtain information on the impact of migration on older adults in rural areas. Associations are examined from both the perspectives of parents ( N = 883) and migrating children ( N = 2,150) using equations that adjust for demographic characteristics of parents and children and factors that may indicate unmet support needs. Results: A robust association with poor health promoting migration returns from both parent and child perspective exists and remains even with controls that might attenuate the relationship. Discussion: Although media discussions have pointed out dangers of out-migration for older adults, little systematic evidence exists. This study supports the viewpoint that accommodations for older adults can be made despite social changes promoting out-migration and demographic aging of the population.
Protection by pentoxifylline of malathion-induced toxic stress and mitochondrial damage in rat brain
Authors: Ranjbar Akram , Ghahremani Mohammad Hossein , Sharifzadeh Mohammad , Golestani Abolfazl , Ghazi-Khansari Mahmood , Baeeri Maryam , Abdollahi Mohammad
Published: March 2010

Objective: The objective of this study was to investigate the possible protective effects of pentoxifylline as a phosphodiesterase-5 inhibitor on malathion-induced oxidative damage to rat brain mitochondria. Methods: Rats received malathion (200 mg/kg/day) and pentoxifylline (PTX, 50 mg/kg/day) in combination or alone. Alpha-tocopherol (AT, 15 mg/kg/day) was used as a positive standard. After 1 week of treatment, blood, whole brain tissue, and brain mitochondria were isolated. The activity of enzymatic scavengers such as glutathione peroxidase (GPx), catalase (CAT), copper-zinc superoxide dismutase (Cu/ZnSOD), and manganese superoxide dismutase (MnSOD) were measured. The extents of cellular lipid peroxidation (LPO), nitrotyrosine (NOx), and the ratio of reduced versus oxidized glutathione (GSH/GSSG) were determined. The protein expression of MnSOD was determined in brain mitochondria. Results: Malathion stimulated activities of CAT, Cu/ZnSOD, GPx, and increased LPO and NOx, and decreased GSH/GSSG in whole brain homogenate. The changes in CAT, LPO, GPx, and GSH/GSSG were restored by PTX and AT. In plasma samples, malathion increased CAT, Cu/ZnSOD, and GPx activities, increased LPO, and decreased GSH/GSSG, while PTX and AT attenuated malathion-induced changes in GPx, Cu/ZnSOD, LPO, and GSH/GSSG. In brain mitochondria, malathion enhanced LPO, NOx, CAT, GPx, and MnSOD and decreased GSH/GSSG as compared to controls, whereas PTX and AT restored malathion-induced changes in GSH/GSSG, NOx, GPx, and CAT. Malathion noticeably enhanced expression of MnSOD protein as compared to controls. Malathion decreased viability of mitochondria that was recovered by AT. It is concluded that oxidative damage is at least in part the mechanism of toxicity of malathion in the mitochondria that can be recovered by PTX comparable to AT.