bluuebunny/crossref_metadata_2025 huggingface dataset:
Moniteur sportif et sociologue: Récit d’une observation participante clandestine
Authors: Soulé Bastien , Richet Cédric
Published: October 2010

Sports Instructor and Sociologist: A Covert Participant Observation: This paper describes the change of status and viewpoint inherent in the shift from a sports instructor job to the implementation of a participant observation. The latter was undertaken to grasp the stakes and difficulties of a sports facility delegated management. Beside the results of this investigation, we also intend to relate a peculiar process, including the combination of multiple and varying roles, as well as a dynamic relation to the fieldwork and its participants. As the observation remained concealed, this role duplicity had many consequences: beyond personal and psychological ones, the effects are also professional, relational, methodological, heuristic and ethical.
An Unusual Case of Erb’s Palsy in a Neonate: A Case Report
Authors: Louis Deepak , Sundaram Venkataseshan , Samujh Ram
Published: October 2010

Erb’s palsy occurs in neonates following traumatic delivery, where excessive traction on the neck stretches these nerve roots. Nonobstetric causes of Erb’s palsy are rare in neonates. The authors report the presentation of a female neonate with Erb’s palsy following a postero-lateral thoracotomy. The infant underwent surgery on day 3 of life for esophageal atresia and presented with right upper limb weakness on day 21 of life. She demonstrated features of Erb’s palsy with normal higher mental functions. An electromyography and nerve conduction study confirmed Erb’s palsy. The surgical procedure in the index case did not involve the brachial plexus. However, her right upper limb was positioned hyperabducted during the intraoperative period, which possibly had led to the palsy. The key message of this report is that prolonged stretching of the brachial plexus roots during surgery of the neck and thorax can be an important nonobstetric cause of Erb’s palsy in neonates
The Genetics of Parkinson Disease
Authors: Bekris Lynn M. , Mata Ignacio F. , Zabetian Cyrus P.
Published: October 2010

Parkinson disease (PD) is the second most common neurodegenerative disorder. In most instances, PD is thought to result from a complex interaction between multiple genetic and environmental factors, though rare monogenic forms of the disease do exist. Mutations in 6 genes (SNCA, LRRK2, PRKN, DJ1, PINK1, and ATP13A2) have conclusively been shown to cause familial parkinsonism. In addition, common variation in 3 genes (MAPT, LRRK2, and SNCA) and loss-of-function mutations in GBA have been well-validated as susceptibility factors for PD. The function of these genes and their contribution to PD pathogenesis remain to be fully elucidated. The prevalence, incidence, clinical manifestations, and genetic components of PD are discussed in this review.
Genetic Causes of Frontotemporal Degeneration
Authors: See Tricia M. , LaMarre Amanda K. , Lee Suzee E. , Miller Bruce L.
Published: October 2010

The purpose of this review is to provide a comprehensive update on the genetic causes of frontotemporal lobar degeneration (FTLD). Approximately 40% to 50% of patients diagnosed with FTLD have a family history of a ‘‘related disorder,’’ whereas 10% to 40% have an autosomal dominant family history for the disease. At this time, mutations occurring in 2 independent genes located on the same chromosome (MAPT and GRN) have been shown to cause the majority of cases of autosomal dominant FTLD. Specific genetic, molecular, pathological, and phenotypic variations associated with each of these gene mutations are discussed, as well as markers that may help differentiate the 2. In addition, 3 relatively rare, additional genes known to cause familial FTLD are examined in brief. Lastly, genetic counseling issues which may be important to the community clinician are discussed.
The Prion Diseases
Authors: Brown Khalilah , Mastrianni James A.
Published: October 2010

The prion diseases are a family of rare neurodegenerative disorders that result from the accumulation of a misfolded isoform of the prion protein (PrP), a normal constituent of the neuronal membrane. Five subtypes constitute the known human prion diseases; kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), fatal insomnia (FI), and variant CJD (vCJD). These subtypes are distinguished, in part, by their clinical phenotype, but primarily by their associated brain histopathology. Evidence suggests these phenotypes are defined by differences in the pathogenic conformation of misfolded PrP. Although the vast majority of cases are sporadic, 10% to15% result from an autosomal dominant mutation of the PrP gene (PRNP). General phenotype-genotype correlations can be made for the major subtypes of CJD, GSS, and FI. This paper will review some of the general background related to prion biology and detail the clinical and pathologic features of the major prion diseases, with a particular focus on the genetic aspects that result in prion disease or modification of its risk or phenotype.
Daily Use of Complementary and Other Therapies for Symptoms Among Older Adults: Study Design and Illustrative Results
Authors: Arcury Thomas A. , Grzywacz Joseph G. , Neiberg Rebecca H. , Lang Wei , Nguyen Ha T. , Altizer Kathryn , Stoller Eleanor P. , Bell Ronny A. , Quandt Sara A.
Published: October 2010

Objectives: This article describes research designed to specify complementary therapies used among older adults by obtaining daily use data and the specific purposes for use. Design: Two hundred African American and White participants completed a baseline interview and up to six sets of three daily-diary interviews at monthly intervals. Results: Participants provided retrospective information on complementary therapy use and information on the use of therapies for specific symptoms experienced across 3,070 person days. Retrospective information indicated that most participants used complementary therapies (e.g., 85.0% used home remedies in the past year). The use of complementary or other therapies and the number of days the therapies were used varied for specific symptoms. For example, home remedies were used on 86 (9.1%) of the 944 person days for which joint pain was reported. Discussion: The daily-diary design provides detailed information for delineating how elders include complementary and other therapies in their health self-management.
Aconitine intoxication mimicking acute myocardial infarction
Authors: Lin Chun-Chi , Phua Dong-Haur , Deng Jou-Fang , Yang Chen-Chang
Published: October 2010

Introduction: Cardiotoxicity in acute aconitine intoxication is well known; however, elevation of troponin I level and abnormal scintigraphy findings had not previously been reported. Case report: A 60-year-old man developed chest tightness, syncope and convulsion after ingesting processed Aconitum carmichaeli (Chuanwu) extract for treatment of headache. Electrocardiogram showed first degree atrioventricular (AV) block. Troponin I level was elevated at 14.8 ng/mL 13 hours post-ingestion. Creatine kinase was also increased to 414 U/L. However, echocardiography did not show any abnormal cardiac wall motion. Tc-99m-PYP scintigraphy revealed diffusely increased uptake in the myocardium, suggesting the presence of myocardial necrosis or myocarditis. Discussion: Aconitine poisoning can mimic acute myocardial infarction with chest tightness and elevated cardiac enzymes. Increased cardiac markers and myocardial insult seen in this patient were likely to be related to the toxicity of aconitine. Care should be taken in making the diagnosis in such instances. Management is primarily supportive.
Apigenin induces apoptosis in human lung cancer H460 cells through caspase- and mitochondria-dependent pathways
Authors: Lu Hsu-Feng , Chie Yu-Jie , Yang Ming-Sung , Lu Kung-Wen , Fu Jene-John , Yang Jai-Sing , Chen Hung-Yi , Hsia Te-Chun , Ma Chia-Yu , Ip Siu-Wan , Chung Jing-Gung
Published: October 2010

Apigenin (4,5,7-trihydroxyflavone), a promising chemopreventive agent presented in fruits and vegetables, has been shown to induce cell cycle arrest and apoptosis in many types of human cancer cell lines. However, there is no available information to address the effects of apigenin on human lung cancer H460 cells. In the present studies, H460 cells were treated with apigenin for different time and then were analyzed for the morphological changes, induction of apoptosis, protein levels associated with apoptosis and results in dose-dependent induction of morphological changes, decrease in the percentage of viability, induced DNA damage and apoptosis; down-modulation of the protein expression of Bid, Bcl-2, procaspase-8; up-regulation of protein levels of Bax, caspase-3, AIF, cytochrome c, GRP78 and GADD153; decreased the levels of mitochondrial membrane potential and increased the productions of reactive oxygen species (ROS) and Ca2+ in H460 cells. Taken together, this is the first systematic in vitro study showing the involvement of apoptosis regulatory proteins as potential molecular targets of apigenin in human lung cancer H460 cells.
Depression predicts self-reported disease activity in systemic lupus erythematosus
Authors: Carr FN , Nicassio PM , Ishimori ML , Moldovan I , Katsaros E , Torralba K , Shinada S , Cooray D , Wallace DJ , Finck S , Jolly M , Wilson AL , Weisman MH
Published: October 2010

Systemic lupus erythematosus (SLE) is an autoimmune disease that can significantly impact both physiological and psychological functioning. In order to examine the relationship between psychological functioning and disease activity in SLE, we administered instruments that collected sociodemographic information and measured indices of disease activity and psychosocial functioning from 125 adult Hispanic and White patients with SLE. Patients were recruited from four healthcare settings in the greater Southern California area. Both cross-sectional and longitudinal relationships between depression and disease activity were evaluated. Cross-sectional findings revealed that depression and ethnicity were independently correlated with self-reported disease activity. Longitudinally, depression alone predicted self-reported disease activity. These data suggest that depression may play a significant role in the health status of SLE patients and serve as an important target for clinical intervention.
Serum procalcitonin does not differentiate between infection and disease flare in patients with systemic lupus erythematosus
Authors: Lanoix JP , Bourgeois AM , Schmidt J , Desblache J , Salle V , Smail A , Mazière JC , Betsou F , Choukroun G , Duhaut P , Ducroix JP
Published: October 2010

Systemic erythematosus lupus (SLE) is a common autoimmune disease. Disease flares may mimic infection with fever, inflammatory syndrome and chills, sometimes resulting in a difficult differential diagnosis. Elevated serum procalcitonin (PCT) levels have been reported to be predictive of bacterial infections, but with conflicting results. The value of serum procalcitonin has not been assessed in large series of SLE. We aimed to describe the distribution of PCT levels in SLE patients with and without flares, to assess the factors associated with increased PCT levels, and to determine the positive and negative predictive values of increased PCT for bacterial infection in SLE patients. Hospitalized SLE patients were included in a retrospective study. Serum PCT had been assayed, or a serum sample had been frozen on admission, before treatment modification. Serum PCT, measured by an automated immunofluorometric assay, and SLEDAI were assessed at the same time. Some 53 women (median age: 33.7 years, range 16–76) and seven men (median age: 52.5 years ± 19) were included. The median SLEDAI for patients with flare ( n = 16, 28%) was 2 (range: 0–29). Five patients (8%) had systemic infection. Only one patient had increased PCT levels. Men had significantly higher PCT levels than women (0.196 ± 0.23 versus 0.066 ± 0.03, p < 0.01) and a significant correlation was observed between PCT, age, erythrocyte sedimentation rate, and C-reactive protein. We conclude that PCT levels were within the normal range in infected and non-infected SLE patients and there was no ability to differentiate SLE patients with or without bacterial infection.
Total serum IgE levels in systemic lupus erythematosus and associations with childhood onset allergies
Authors: Parks CG , Biagini RE , Cooper GS , Gilkeson GS , Dooley MA
Published: October 2010

Elevated serum IgE has been described in systemic lupus erythematosus (SLE), but associations with disease risk and characteristics remain unresolved. We assessed total serum IgE levels and atopy (IgE > 100 IU/ml) in recently diagnosed SLE patients (n = 228) compared with population controls (n = 293) and in relation to disease activity, autoantibodies, clinical features, total immunoglobulins, C-reactive protein, and allergy history. Multivariate models estimated determinants of IgE and atopy in patients and controls, and associations of SLE with allergy and atopy. Total IgE levels were higher in patients than controls (median = 42 vs. 29 IU/ml); 32% of patients and 25% of controls were atopic (p = 0.06). IgE levels were significantly higher in non-Whites and patients reporting childhood onset (<18 years) asthma and hives, and in controls reporting childhood asthma, hay fever, eczema, and adult onset hives. After accounting for racial differences, atopy was not associated with SLE, nephritis, or other clinical and laboratory parameters. In sum, our findings provide limited evidence of a direct association between total serum IgE and SLE overall or with other disease characteristics after adjusting for demographic characteristics and allergy history. Future studies may want to explore potentially shared risk factors for development of allergy, atopy, and SLE.
Getting Lost in Buildings
Authors: Carlson Laura A. , Hölscher Christoph , Shipley Thomas F. , Dalton Ruth Conroy
Published: October 2010

People often get lost in buildings, including but not limited to libraries, hospitals, conference centers, and shopping malls. There are at least three contributing factors: the spatial structure of the building, the cognitive maps that users construct as they navigate, and the strategies and spatial abilities of the building users. The goal of this article is to discuss recent research on each of these factors and to argue for an integrative framework that encompasses these factors and their intersections, focusing on the correspondence between the building and the cognitive map, the completeness of the cognitive map as a function of the strategies and individual abilities of the users, the compatibility between the building and the strategies and individual abilities of the users, and complexity that emerges from the intersection of all three factors. We end with an illustrative analysis in which we apply this integrative framework to difficulty in way-finding.
Toward a More Social Understanding of Achievement Goals
Authors: Poortvliet P. Marijn , Darnon Céline
Published: October 2010

The current article presents an overview of recent research into social outcomes that accompany the pursuit of achievement goals. On the basis of investigations in various subdisciplines of psychology, we conclude that mastery goals—striving to improve one’s own performance—lead to investments in exchange relationships, endorsement of reciprocity norms, and active efforts to integrate different opinions. In contrast, performance goals—striving to outperform others—may result in rather maladaptive social behaviors. We point to three promising avenues for future research: Social consequences of achievement goals could be studied from a multiple-goal perspective, different levels of analysis should be taken into account, and the role of status differences should be examined.
From Scanner to Sound Bite
Authors: Fine Cordelia
Published: October 2010

Neuroimaging research is yielding reports of sex differences in the brain. Yet the likelihood of spurious findings of sex differences, the teething problems of new technology, the obscurity of the relation between brain structure and psychological function, and difficulties inferring mental states from neuroimaging data all require us to be considerably cautious in interpreting such results. Unfortunately, these issues are often overlooked in popular accounts. Together with a tendency for people to regard neuroscientific information as more scientific than behavioral data, and as indicative of male and female “nature,” these issues point to the worrisome possibility of public misunderstanding of what contemporary neuroscience tells us about gender.
All in the Family: Comparing Siblings to Test Causal Hypotheses Regarding Environmental Influences on Behavior
Authors: Lahey Benjamin B. , D’Onofrio Brian M.
Published: October 2010

Psychologists in both basic and applied fields are keenly interested in the environmental influences that shape our lives. Therefore, researchers test causal hypotheses to construct models of environmental influences that can withstand attempts at refutation. Randomized experiments provide the strongest tests of causal hypotheses but are not always feasible, and their assumptions cannot always be met. In such cases, a number of quasi-experimental research designs can be used to substantially reduce confounding in tests of causal hypotheses. Sibling-comparison designs provide robust quasi-experimental tests of causal environmental hypotheses, but they are underused in psychology in spite of their power, feasibility, and convenience.
Sleep’s Role in the Consolidation of Emotional Episodic Memories
Authors: Payne Jessica D. , Kensinger Elizabeth A.
Published: October 2010

Emotion has a lasting effect on memory, encouraging certain aspects of our experiences to become durable parts of our memory stores. Although emotion exerts its influence at every phase of memory, this review focuses on emotion’s role in the consolidation and transformation of memories over time. Sleep provides ideal conditions for memory consolidation, and recent research demonstrates that manipulating sleep can shed light on the storage and evolution of emotional memories. We provide evidence that sleep enhances the likelihood that select pieces of an experience are stabilized in memory, leading memory for emotional experiences to home in on the aspects of the experience that are most closely tied to the affective response.
The Protracted Collapse of Ghana Airways: Lessons in Organizational Failure
Authors: Amankwah-Amoah Joseph , Debrah Yaw A.
Published: October 2010

Although the importance of organizational failure has fostered a steady stream of research, a review of the literature suggests that the majority of studies have focused on firms in the private sector and in developed economies. Despite the increasing occurrence of state-owned firms failing in many developing countries, empirical research on this issue remains scant. Using an in-depth case study of Ghana Airways, this article examines the causes of failure of state-owned organizations in developing countries. This study revealed that, in addition to external factors such as liberalization, frequent changes of the top management team and the decision makers’ characteristics contributed significantly to the firm’s demise. The theoretical, managerial, and policy implications of these findings are discussed.
Exploring the Impact of Community and Organizational Social Capital on Government Performance
Authors: Andrews Rhys
Published: October 2010

Civic-republican theories of democracy assume high levels of social capital within the community and within public bureaucracies will be associated with better government performance. This article tests these assumptions by analyzing the impact of community and organizational social capital on the achievements of English local governments. The interdependence between social capital and performance is modeled using a range of primary and secondary data. The statistical results suggest that both community and organizational social capital are positively related to government performance. However, further analysis revealed that the combined effects of these two forms of social capital are not beneficial for performance.
Review Article: Combination of Clopidogrel and Proton Pump Inhibitors: Implications for Clinicians
Authors: Tran Marie , Tafreshi Javad , Pai Ramdas G.
Published: October 2010

Objectives: To evaluate the existing literature on a proposed interaction between clopidogrel and proton pump inhibitors (PPIs) and discuss its implications for clinicians treating patients with this combination therapy. Background: Each year millions of patients receive antiplatelet therapy. A number of these patients are prescribed PPIs concomitantly to reduce the risk of gastrointestinal side effects associated with antiplatelet therapy. Several studies have been published recently addressing a potential adverse drug-drug interaction between clopidogrel and PPIs. Methods: Literature was evaluated through Pubmed using the terms clopidogrel, PPI, prasugrel, cytochrome P450, genetic polymorphisms, H 2 blockers, famotidine, genetic cytochrome P450 polymorphisms, and drug interaction. Articles with these terms were considered for evaluation. In addition, reference citations from publications identified in the searches were further reviewed and analyzed. Results: None of the currently published studies were specifically designed to evaluate this drug-drug interaction or address the clinical relevance of this interaction prospectively. Conflicting evidence raised concerns but the information did not conclude with certainty a cause-and-effect relationship between concomitant use of the drugs and emerging safety issues. However, the Food and Drug Administration issued a public-health warning on the possible interaction between clopidogrel and PPIs, predominantly with omeprazole, in November 2009. Conclusions: Controversies exist on a potential drug-drug interaction between clopidogrel and PPIs. Although further studies are warranted, several studies indicated that there was a drug-drug interaction through this combination therapy with detrimental clinical outcomes and increased costs. Studies suggested that the use of a PPI may make clopidogrel less effective resulting in a higher risk of myocardial infarction, stroke, or death. Until additional information becomes available clinicians should consider discontinuing PPI use if no clear indication is documented. Alternative options like H2-receptor antagonists should be considered. Upon availability, genetic testing may provide additional valuable information.
A Randomized Trial of Aspirin at Clinically Relevant Doses and Nitric Oxide Formation in Humans
Authors: Hennekens Charles H. , Schneider Wendy R. , Pokov Alex , Hetzel Scott , DeMets David , Serebruany Victor , Schröder Henning
Published: October 2010

Background: We performed the first test in humans of whether aspirin at clinically relevant doses increases nitric oxide (NO) formation. Methods: Seventy primary prevention patients with metabolic syndrome were randomly assigned to 81 mg, 162.5 mg, 325 mg, 650 mg, or 1300 mg aspirin daily for 12 weeks to test changes in heme oxygenase (HO-1), a downstream target of NO formation and asymmetrical dimethylarginine (ADMA), a competitive inhibitor of NO synthase. Findings: For HO-1, the mean was 29.37 nanograms per milliliter at baseline and 57.45 at 12 weeks giving a mean ratio (MR) of 1.96 (P < .001) and 95% confidence interval (CI) from 1.91 to 2.00. There was no effect modification by dose or gender (P = .341). For ADMA, the mean was 1.70 micromoles per liter at baseline and 0.81 at 12 weeks, giving an MR of 0.48 (P < .001) and CI from 0.46 to 0.49. There was no effect modification by dose but a possible difference by gender (P = .055). Interpretation: In high-risk primary prevention patients, aspirin significantly increases markers of NO formation. All doses produce similar increases in HO-1 and decreases in ADMA. The antiplatelet properties of aspirin to irreversibly inhibit platelet dependent cyclooxygenase are sufficient to explain benefits in patients with occlusive vascular diseases. Nonetheless, these data contribute to the formulation of the hypothesis that aspirin has additional beneficial effects mediated through NO formation. Further research, including direct randomized comparisons on atherosclerosis using noninvasive techniques as well as on occlusive vascular disease events, is necessary to test whether this hypothesis has clinical or public health relevance.
Protective Effect of L-Arginine in Experimentally Induced Myocardial Ischemia: Comparison With Aspirin
Authors: Saleh Alaaeldin I. , Abdel Maksoud Sahar M. , El-Maraghy Shohda A. , Gad Mohamed Z.
Published: October 2010

Objective: Coronary artery diseases including myocardial ischemia (MI) remain one of the leading causes of death worldwide. This study was designed to compare the protective effect of L-arginine versus aspirin from the biochemical changes associated with MI injury. Experimental design: Four groups of male New Zealand white rabbits were investigated. Normal group (n = 8) rabbits were fed standard chow pellets, untreated MI group (n = 16), where hypercholesterolemia was induced by feeding the animals with a diet containing 2% cholesterol for 28 days, L-arginine group (n = 12) rabbits were fed a 2% cholesterol-enriched diet in conjunction with L-arginine (2.25 g %) in drinking water for 28 days, and aspirin group (n = 12) rabbits were fed 2% cholesterol-enriched diet in conjunction with aspirin administered orally (0.7 mg/kg per d) for 28 days. After 28 days, MI was induced in all groups, except the normal group, by a single subcutaneous (sc) injection of isoproterenol hydrochloride (0.2 mg/kg body weight [bw]). Animals were sacrificed 6 hours later. Results: Our results showed that L-arginine was more effective than aspirin in reducing platelet aggregation, reducing low-density lipoprotein (LDL) oxidizability, preventing aortic intimal thickening, and maintaining histological architecture of the myocardium. Both drugs, however, had similar positive effects on plasma fibrinogen levels and on the prevention of myocardial release of cardiac troponin I and creatine kinase-MB. The effect on hypercholesterolemia was insignificant for both drugs. Aspirin was more effective than L-arginine in prolonging prothrombin time. Conclusion: L-arginine supplementation represents a potentially novel nutritional strategy for preventing and treating coronary artery diseases especially in cases of aspirin resistance and/or hypersensitivity.
Roles of Cyclooxygenase 2 in Sevoflurane- and Olprinone-Induced Early Phase of Preconditioning and Postconditioning Against Myocardial Infarction in Rat Hearts
Authors: Tosaka Shinya , Tosaka Reiko , Matsumoto Shuhei , Maekawa Takuji , Cho Sungsam , Sumikawa Koji
Published: October 2010

Purpose: It is known that selective cyclooxygenase 2(COX-2) inhibitors increase mortality in patients with previous myocardial infarction, and it has been suggested that COX-2 plays an important role in cardioprotection against ischemia. The current study was carried out to determine whether COX-2 is involved in the mechanisms of sevoflurane- and olprinone-induced early-phase preconditioning (E-PreC) and postconditioning (PostC) in rat hearts. Methods: Male Sprague-Dawley rats were anesthetized with sodium pentobarbital. After opening the chest, all rats underwent 30-minute occlusion of left anterior descending coronary artery followed by 2-hour reperfusion, and the infarct size was measured after the reperfusion. The rats were randomly assigned to groups with pre- and postischemic exposure to sevoflurane and administration of olprinone with or without a selective COX-2 inhibitor, NS-398. Results: The infarct size in the control group was 42% ± 6% of the area at risk. Infarct size was significantly reduced by pre- and postischemic administration of sevoflurane (16% ± 7% and 17% ± 6%, respectively), as well as by olprinone (14% ± 4% and 15% ± 10%, respectively). NS-398 prevented the protective effects of both pre- and postischemic exposure to sevoflurane (35% ± 8% and 42% ± 10%, respectively), whereas the protective effect of both pre- and postischemic administration of olprinone was not influenced by NS-398 (12% ± 5% and 19% ± 7%, respectively). Conclusions: Cyclooxygenase 2 could be a critical mediator of sevoflurane-induced but not olprinone-induced E-PreC or PostC in rat hearts.
Postconditioning: From the Bench to Bedside
Authors: Cour Martin , Gomez Ludovic , Mewton Nathan , Ovize Michel , Argaud Laurent
Published: October 2010

Infarct size is determined not only by the severity of ischemia but also by pathological processes initiated at reperfusion. Accumulating experimental evidence indicates that lethal reperfusion injury might account for up to half of the final size of the myocardial infarct. Ischemic postconditioning (brief repeated periods of ischemia-reperfusion applied at the onset of coronary reflow) has been recently described as a powerful cardioprotection mechanism that prevents lethal reperfusion injury. This is the first method proven to reduce the final infarct size by about 50% in several in vivo models and to be confirmed in recent preliminary human studies. The molecular pathways are incompletely mapped but they probably converge to a mitochondrial key target: the mitochondrial permeability transition pore (PTP) which opening during early reperfusion is an event that promotes myocardial cell death. In different animal models and experimental settings, pharmacological PTP inhibition at the onset of reperfusion reproduces all the cardioprotective effects of ischemic postconditioning. In a recent proof-of-concept trial, the administration (just before percutaneous coronary intervention) of cyclosporine A, a potent PTP inhibitor, was associated with smaller infarct size. This review will focus on the physiological preclinical data on both ischemic and pharmacological postconditioning that are relevant to their translation to clinical therapeutics.
Thermal buckling and nonlinear flutter behavior of shape memory alloy hybrid composite plates
Authors: Ibrahim Hesham Hamed , Tawfik Mohammad , Negm Hani Mohammed
Published: October 2010

A new nonlinear finite element model is provided for the nonlinear flutter response of shape memory alloy (SMA) hybrid composite plates under the combined effect of thermal and aerodynamic loads. The nonlinear governing equations for moderately thick rectangular plates are obtained using first-order shear-deformable plate theory, von Karman strain-displacement relations and the principle of virtual work. To account for the temperature dependence of material properties, the thermal strain is stated as an integral quantity of thermal expansion coefficient with respect to temperature. The aerodynamic pressure is modeled using the quasi-steady first-order piston theory. Newton-Raphson iteration method is employed to obtain the thermal post-buckling deflection, while the linearized updated mode method is implemented in predicting the limit-cycle oscillation at elevated temperatures. Numerical results are presented to show the thermal buckling and flutter characteristics of SMA hybrid composite plates, illustrating the effect of the SMA volume fraction and pre-strain value on the aero-thermo-mechanical response of such plates.
Identification of seismically excited buildings with two orthogonal horizontal components
Authors: Angeles-Cervantes J. Mauricio , Alvarez-Icaza Luis
Published: October 2010

An algorithm is presented here to identify parameters of linear models of buildings under orthogonal bi-dimensional seismic excitation, using acceleration measurements of sensors arbitrarily arranged on the stories, in real time. The model considers three degrees of freedom for each story and uses an efficient reparameterization of the least-squares algorithm that allows a very important reduction in the number of calculations, when compared with the standard formulation. Results obtained from simulations and with data obtained from instrumented buildings confirm the efficacy of the proposed method.
Experimental analysis of active-passive vibration control using viscoelastic materials and extension and shear piezoelectric actuators
Authors: Trindade Marcelo A
Published: October 2010

Hybrid active—passive damping treatments combine the reliability, low cost and robustness of viscoelastic damping treatments and the high-performance, modal selective and adaptive piezoelectric active control. Numerous hybrid damping treatments have been reported in the literature. They differ mainly by the relative positions of viscoelastic treatments, sensors and piezoelectric actuators. In this work we present an experimental analysis of three active—passive damping design configurations applied to a cantilever beam. In particular, two design configurations based on the extension mode of piezoelectric actuators combined with viscoelastic constrained layer damping treatments and one design configuration with shear piezoelectric actuators embedded in a sandwich beam with viscoelastic core are analyzed. For comparison purposes, a purely active design configuration with an extension piezoelectric actuator bonded to an elastic beam is also analyzed. The active—passive damping performance of the four design configurations is compared. Results show that active—passive design configurations provide more reliable and wider-range damping performance than the purely active configuration.
Sensitivity analysis for vibration transfer path systems with non-viscous damping
Authors: Yimin Zhang  , Xianzhen Huang  , Qun Zhao
Published: October 2010

In this paper, based on the dynamic sensitivity technique, we propose a method for sensitivity analysis of vibration transfer path systems with respect to their path parameters. It is well known that non-viscous damping is an important factor in causing the nonlinearity of vibration systems. The sensitivity of nonlinear vibration systems with respect to different kinds of non-viscous damping is discussed. With the sensitivity of dynamic responses with respect to transfer path parameters as an evaluation criterion, the contribution level of each transfer path to the vibration of acceptance structures was listed in order. Using the proposed method, the sensitivity of the vibration system with multiple and/or multi-dimensional transfer paths could be determined explicitly and accurately in the time domain.
Flexural wave propagation in coated poroelastic cylinders with reference to fretting fatigue
Authors: Ahmed Shah S.
Published: October 2010

Fretting is a contact fatigue phenomenon, but the bulk stresses and material properties contribute to final failure. The near-surface state of stress developed under oscillatory contact between machine elements plays a major role in deciding the severity of fretting. It is common to coat the core or provide surface treatment. The coating material is chosen to give good tribological properties. Such coatings exert a larger influence on the near-surface state of stress. It is possible to enhance tribological properties by coating the surface. Flexural wave propagation in coated poroelastic cylinders of infinite extent is investigated employing Biot’s theory. The coated poroelastic cylinder consists of two poroelastic cylinders of different poroelastic materials bonded at the curved surface. Each material is taken to be homogeneous and isotropic. A perfect bond is assumed at the interface and outer boundary of the coated cylinder is treated as traction free. Frequency equations of coated poroelastic cylinders are derived both for pervious and impervious surfaces. At the interface of the core and coating, the stresses and displacements are continuous. The nondimensional phase velocity for propagating modes is computed as a function of the propagation constant in the absence of dissipation. The results are presented graphically for two types of coated poroelastic cylinders and then discussed.
An intelligent system for faulty-bearing detection based on vibration spectra
Authors: Marichal GN , Artés M. , García-Prada JC
Published: October 2010

In this paper, a new detection and classification system of faulty bearings is presented. This system is based on artificial intelligent techniques and vibration signals in the frequency domain produced by the faulty bearings. The system consists of several neuro-fuzzy systems in cascade, along with measurement equipment for the vibration spectral data. These neuro-fuzzy systems have been used as bi-classifiers. That is, each neuro-fuzzy system is specialized in the classification between two different types of rolling bearing status. A careful selection process for rules has been included in the learning algorithm. Moreover, the demodulated vibration signal has been used as input to the neuro-fuzzy systems based on the Sugeno approach. Several trials were carried out, taking into account the vibration spectral data collected by the measurement equipment for each bearing. Different results with three types of faulty bearings using the proposed approach are shown, where satisfactory results have been achieved.
Discrete-time adaptive sliding mode control for a class of uncertain time delay systems
Authors: Yoshimura Toshio
Published: October 2010

This paper is concerned with a discrete-time adaptive sliding mode control for a class of uncertain time delay systems. It is assumed that the dynamic systems are described by a discrete-time time delay state equation with mismatched uncertainties, and that the states are measured in the contamination with independent random noises. The augmented state equations are derived based on the state of the time delay, and the weighted extended Kalman filter and the weighted least squares estimator to take the estimates for the augmented states and the uncertainties are proposed. The discrete-time adaptive sliding mode control is designed using the integral-type sliding surface and the output information obtained from the estimators. It is verified that the estimation errors converge to zero as time increases, and the states for the dynamic systems are ultimately bounded under the action of the proposed adaptive sliding mode control. The effectiveness of the proposed method is indicated by the simulation experiment in a simple numerical example.
Studies of the performance of particle dampers attached to a two-degrees-of-freedom system under random excitation
Authors: Zheng Lu  , Masri Sami F , Xilin Lu
Published: October 2010

This paper presents an investigation of the performance of particle dampers attached to a two-degrees-of-freedom system, using the discrete-element method. Correlation functions, the amount of dissipated energy due to impact and friction, and the concept of ‘‘effective momentum exchange’’ are shown to be suitable ways of interpreting the physics involved in the behavior of particle dampers. Using three different types of excitation, the optimum operating regions are determined, within which particles move in a plug flow pattern and correlation functions decay fast, while the dissipated energy and the effective momentum exchange are large compared with inefficient operating conditions. The paper also evaluates the effects of many system parameters (such as the mass ratio, coefficient of restitution, excitation levels, damping ratio of the primary system, container dimensions and shape, number of particles, and the coefficient of friction), using high-fidelity simulations. It is shown that: increasing the mass ratio can improve the damper’s effectiveness, but only up to a certain level; applying particles with a high value of the coefficient of restitution can result in a broader range of acceptable response levels; friction has a complex influence on particle dampers in a generally detrimental form; a lightly-damped primary system can achieve a considerable reduction in its response with a small weight penalty; and that a cylindrical-shaped container provides a higher level of effectiveness than a rectangular-shaped one. Finally, the behavior of the particle damper is compared to a multi-unit impact damper to enhance the understanding of the two passive control devices, and it is shown that a particle damper is more robust when considering arbitrary levels of excitation in different directions.
Moment Lyapunov exponents and stochastic stability of moving narrow bands
Authors: Kozić Predrag , Pavlović Ratko , Janevski Goran , Stojanović Vladimir
Published: October 2010

Stochastic stability of narrow moving bands under random tension fluctuation is investigated within the concept of the Lyapunov exponent. The moment Lyapunov exponents and Lyapunov exponents are important characteristics determining the moment and almost-sure stability boundaries of a stochastic dynamical system. Galerkin’s method is used to reduce the partial differential equation of motion to a corresponding ordinary differential equation with randomly varying stiffness. We obtain explicit stability conditions based on the asymptotic expansion series for the moment Lyapunov exponent g(p), and the Lyapunov exponent λ for a two-dimensional linear stochastic system.
Fractional optimal control problems: a pseudo-state-space approach
Authors: Raj Kumar Biswas  , Sen Siddhartha
Published: October 2010

A scheme for optimal control problem formulation and solution of a fractional order system using pseudo-state-space formulation is presented in this paper. A pseudo-state-space representation for a particular type of fractional dynamical equation is proposed. The dynamic constraint is in the form of a fractional differential equation that includes integer derivatives in addition to the fractional derivatives. The order of the fractional derivatives is taken as less than one and fractional derivatives are defined in terms of Riemann-Liouville. The performance index considered is a function of both the state and the control variables. Using the proposed pseudo-state-space model a new formulation of a class of fractional optimal control problem is developed. A direct numerical technique based on Grünwald-Letnikov approximation is used to solve the resulting equations. A numerical example of a fractional order spring-mass-viscodamper system is considered to illustrate the methodology and technique.
Inverse substructure method of three-substructures coupled system and its application in product-transport-system
Authors: Wang Zhi-Wei , Jun Wang
Published: October 2010

An inverse substructure method is developed for the analysis of the dynamical characteristics of a three-substructures coupled system based on the inverse substructure method of a two-substructures coupled system. The unknown substructure-level frequency response functions (FRFs) and coupling stiffness can be predicted, and the system-level response of key components can be obtained by using the method when the system-level FRFs needed are all measured. To verify the validity of the inverse substructure method of a three-substructures coupled system, a lumped mass-spring-damper model with three substructures coupled is taken as an example for numerical validation. The prediction is exactly the same as the ‘‘Given’’. To further check out the accuracy of the method, the experiment of a physical prototype is carried out, and the predicted substructure-level FRFs are in good agreement with those that are measured. The method is applied to the analysis of a product-transport-system, which is treated as a coupled system composed of a key component, a product and a vehicle. The effect of the coupling stiffness on the dynamic response of key components is investigated. The result indicates that reducing the coupling stiffness of the product-vehicle interface can largely lower the response of key components.
Mass and stiffness modifications without changing any specified natural frequency of a structure
Authors: Çakar Orhan
Published: October 2010

The dynamic properties of an existing structure are altered when the mass and stiffness properties of the structure are modified. In some cases it can be desired that a specific natural frequency of the structure should not change after modifications. In case of adding a number of masses on the structure, one of the pre-specified natural frequencies can be preserved by attaching a grounded spring on it. In the present study, a new method is developed based on the Sherman-Morrison formula in order to determine the necessary spring coefficient. The performance of the developed method for damped structures is also investigated. Furthermore, an approach based on minimization of the described objective function is introduced for prediction of the best spring location.
A comparison of dynamic responses of three versions of moving load problem involving elastic rectangular plates
Authors: Gbadeyan JA , Dada MS
Published: October 2010

The dynamic responses of an elastic rectangular plate to some types of moving loads’ distribution are obtained and compared. The partial differential equation describing the force vibration of each system comprising of the elastic rectangular plate and moving load is expressed in terms of each of the three moving loads’ distribution respectively. The three moving loads’ distribution considered are concentrated, uniformly and linearly distributed moving masses. An assumed Series solution in the form of the separation of variables is employed to transform each equation of motion into an ordinary coupled differential equation whose solution is obtained in form of a Duhamel integral. Numerical results are presented for simply supported boundary conditions in graphical and tabular forms. It is found that velocity, moving load’s distribution and mass ratio (Msr) significantly affect the vibration of the elastic rectangular plate.
Modeling and response analysis of dynamic systems by using ANSYS© and MATLAB©
Authors: Khot SM , Yelve Nitesh P
Published: October 2010

In the last decade, many advances and changes have been seen in engineering theory and applications. The modern trend is to combine modeling, theoretical analysis and computer simulation. The conventional techniques of mathematical modeling of real life complicated structural systems for vibration analysis are tedious and time consuming. The finite element (FE) method is becoming popular because of its simplicity and feasibility of using for real life applications. In the present study, extraction of the system model from its FE model by using commercially available softwares such as ANSYS© and MATLAB© is demonstrated. A two-degree-of-freedom spring-mass-damper system is considered here. Its state space mathematical model in principal coordinate system is obtained in MATLAB© from the modal analysis results of its FE model done in ANSYS©. For checking the validity of model, transfer function and state space model in physical coordinates of the same system are derived mathematically by assuming proportional damping. Frequency responses of all the system models are compared and found to be in good agreement. To demonstrate the application of this study, system model of a cantilever beam is also extracted in MATLAB© from the result of modal analysis of its FE model in ANSYS© and its frequency response is plotted. Response of cantilever beam to unit impulse input is also obtained in both ANSYS© and MATLAB© and compared for validating the model. This study will definitely help in simplifying the vibration analysis of real life systems.