bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and Characterization of an Animal Model of Severe Pulmonary Arterial Hypertension
Authors: Morimatsu Yoshitaka , Sakashita Naomi , Komohara Yoshihiro , Ohnishi Koji , Masuda Hiroshi , Dahan Diana , Takeya Motohiro , Guibert Christelle , Marthan Roger
Published: October 2011

Pulmonary arterial hypertension (PAH) is a serious pathological phenomenon with poor prognosis, which is associated with morphological as well as hemodynamic alteration of the pulmonary circulation. To establish an animal model mimicking severe human PAH, we combined 2 well-described procedures, i.e. exposure to hypobaric chronic hypoxia and administration of monocrotaline hydrochloride in rats. Compared to a single procedure, the combined procedure induced more severe right ventricle hypertrophy and an increase in right ventricle systolic pressure. Histological examination on the combined procedure model revealed a severe medial hypertrophy as well as occlusive vascular changes of the intra-acinar pulmonary arteries with endothelial lesions. It is noteworthy that severe alterations including concentric neointimal thickening, abnormal endothelial proliferation, plexiform lesions and vascular occlusion with fibrin thrombi were observed in the combined pulmonary hypertension model when exposed to a long period of hypoxia. The present data indicate that a combined treatment of monocrotaline injection and hypobaric chronic hypoxia exposure produces more severe hemodynamic changes and histological alterations. Since human PAH diagnosed in clinical practice is often severe, this combined treatment animal model could be useful to identify relevant therapeutic targets acting on both hemodynamic and structural alterations of the pulmonary circulation.
Downregulation of Bradykinin Type 2 Receptor Expression in Cardiac Endothelial Cells during Senescence
Authors: Nurmi Laura , Heikkilä Hanna M. , Vapaatalo Heikki , Kovanen Petri T. , Lindstedt Ken A.
Published: October 2011

Objectives: Bradykinin type 2 receptor (BK-2R) knockout mice develop microvascular dysfunction and cardiac hypertrophy. In aged human cardiac microvascular endothelium, dysfunction develops before heart failure symptoms. Since endothelial aging is an independent risk factor for cardiovascular disease, we aimed to clarify the role of kinin receptors in age-related endothelial senescence. Methods and Results: Using qRT-PCR, a downregulation of BK-2Rs during senescence of cultured human coronary artery endothelial cells (HCAECs) and rat cardiac microvascular endothelial cells (RCMECs) was observed. BK-2R downregulation was associated with a decreased cell proliferation rate, with a growth arrest phenotype and reduced angiogenic potential. By staining senescence-associated β-galactosidase, RCMECs from old spontaneously hypertensive rats (SHRs) were found to be significantly more senescent than those derived from age-matched WKY rats, albeit their telomere lengths were similar. Despite downregulation of BK-2Rs and BK-1Rs, a novel family member GPR-100 was highly expressed in HCAECs throughout the culture period. Conclusions: Aging cardiac endothelial cells gradually lose their capacity to express BK-2Rs, and this loss appears to be parallel with a loss of the angiogenic potential of the aging cells. Since RCMECs from hypertensive rats showed premature senescence, hypertension may predispose to cardiac dysfunction by accelerating endothelial aging.
Cx40 Is Required for, and Cx37 Limits, Postischemic Hindlimb Perfusion, Survival and Recovery
Authors: Fang Jennifer S. , Angelov Stoyan N. , Simon Alexander M. , Burt Janis M.
Published: October 2011

Background/Aims: Ischemia induced by large-vessel obstruction or vascular injury induces a complex cascade of vasodilatory, remodeling and inflammatory pathways; coordination of these processes by vascular endothelium is likely to involve endothelial gap junctions. Vascular endothelium predominantly expresses two connexin (Cx) isoforms: Cx37 and Cx40. The relevance of these Cxs to postischemic limb recovery remains unclear. Methods: In this study, we use a well-established, severe femoral-saphenous artery-vein pair resection model of unilateral hindlimb ischemia to test the relevance of Cx37 and Cx40 to postischemic tissue survival and recovery of limb perfusion. Results: Cx40-deficient animals (Cx40–/–) experienced a severe reduction in limb perfusion relative to wild-type (WT) animals and exhibited profound and rapid failure of ischemic limb survival. By contrast, the deficit in limb perfusion was less severe in Cx37-ablated (Cx37–/–) animals compared to WT, corresponding with more rapid recovery of limb appearance and use. These results demonstrate that Cx40 is necessary for postischemic limb survival and reperfusion, whereas Cx37 deletion reduces the extent of ischemia in the same model. Conclusion: In summary, we present evidence demonstrating that Cx37 and Cx40 uniquely regulate postischemic limb perfusion, altering the severity of ischemic insult and consequent postischemic survival.
‘Punctal Switch’ Grafting for the Treatment of Dry Eyes: Our Experience
Authors: Panagopoulos A. , Chalioulias K. , Ramsay A.S.
Published: October 2011

We evaluated the efficacy and safety of ‘punctal switch’ grafting, a proposed new technique for permanent punctal occlusion. We prospectively evaluated the results and complications in 22 patients (5 males and 17 females) who underwent the procedure in our department over a period of 3 years. Patients’ ages ranged from 41 to 81 years. The average follow-up was 12.8 months. Subjective and clinical improvement was documented in 91% of the cases with a low rate of recanalization (9%). Only 1 patient developed epiphora postoperatively, and the operation has been successfully reversed in that case. There were no serious complications. As a conclusion, punctal switch grafting is an effective technique for permanent punctal occlusion. The complication rate is low, recanalization is rare and the occlusion can be reversed if symptomatic epiphora develops.
Understanding Retinopathy of Prematurity: Update on Pathogenesis
Authors: Rivera José Carlos , Sapieha Przemyslaw , Joyal Jean-Sébastien , Duhamel François , Shao Zhuo , Sitaras Nicholas , Picard Emilie , Zhou Ellen , Lachapelle Pierre , Chemtob Sylvain
Published: October 2011

Retinopathy of prematurity (ROP), an ocular disease characterized by the onset of vascular abnormalities in the developing retina, is the major cause of visual impairment and blindness in premature neonates. ROP is a complex condition in which various factors participate at different stages of the disease leading to microvascular degeneration followed by neovascularization, which in turn predisposes to retinal detachment. Current ablative therapies (cryotherapy and laser photocoagulation) used in the clinic for the treatment of ROP have limitations and patients can still have long-term effects even after successful treatment. New treatment modalities are still emerging. The most promising are the therapies directed against VEGF; more recently the use of preventive dietary supplementation with ω-3 polyunsaturated fatty acid may also be promising. Other than pharmacologic and nutritional approaches, cell-based strategies for vascular repair are likely to arise from advances in regenerative medicine using stem cells. In addition to all of these, a greater understanding of other factors involved in regulating pathologic retinal angiogenesis continues to emerge, suggesting potential targets for therapeutic approaches. This review summarizes an update on the current state of knowledge on ROP from our and other laboratories, with particular focus on the role of nitro-oxidative stress and notably trans-arachidonic acids in microvascular degeneration, semaphorin 3 operating as vasorepulsive molecules in the avascular hypoxic retina and in turn impairing revascularization, succinate and its receptor GPR91 in neuron-mediated retinal neovascularization, and ω-3 lipids as modulators of preretinal neovascularization.
Baseline Insulin-Like Growth Factor-I Plasma Levels, Systemic Inflammation, Weight Loss and Clinical Outcome in Metastatic Non-Small Cell Lung Cancer Patients
Authors: Vlachostergios P.J. , Gioulbasanis I. , Kamposioras K. , Georgoulias P. , Baracos V.E. , Ghosh S. , Maragouli E. , Georgoulias V. , Papandreou C.N.
Published: October 2011

Background: Cancer patients frequently suffer from weight loss and systemic inflammation in the context of advanced disease, which is related to adverse outcome. Insulin-like growth factor (IGF)-I is an anabolic molecule implicated in the maintenance of muscle mass and cancer growth. We investigated potential correlations of IGF-I with an inflammatory and weight loss status and with clinical outcome. Methods: Baseline IGF-I plasma levels were measured in 77 patients (66 males, median age 65.5 ± 10.6 years), diagnosed with metastatic non-small cell lung cancer, and were correlated with serum albumin and C-reactive protein (CRP) levels, weight loss history, treatment response and overall survival. Results: IGF-I correlated with age (p = 0.01), histologic subtype (p = 0.019), albumin (p < 0.001) and CRP (p < 0.001). In univariate analysis, gender (p = 0.005), smoking status (p = 0.012), albumin (p = 0.034) and IGF-I (p = 0.017) were related to time to progression, while IGF-I (p = 0.003), gender (p = 0.049) and smoking status (p = 0.003) retained their significance in multivariate analysis. Age (p = 0.005), gender (p = 0.029), weight loss (p = 0.009), performance status (p < 0.001), number of metastatic sites (p = 0.004), albumin (p = 0.008), CRP (p = 0.022) and IGF-I (p = 0.042) were associated with overall survival, although only gender (p = 0.013), weight loss (p = 0.027), performance status (p = 0.015) and number of metastatic sites (p = 0.021) emerged as independent prognostic factors. Conclusion: IGF-I correlates with systemic inflammation and seems to play an independent predictive role in metastatic non-small cell lung cancer.
Focal Rituximab-Induced Edematous Reaction at Primary Cutaneous Follicle Center Lymphoma Lesions: Case Report and Literature Review
Authors: Brunet-Possenti F. , Franck N. , Tamburini J. , Jacobelli S. , Avril M.-F. , Dupin N.
Published: October 2011

Primary cutaneous follicle center lymphoma (PCFCL) is the most common cutaneous B cell lymphoma. It is most often indolent and responds well to rituximab. We present a case of transient rituximab-induced edematous lesions located exclusively on tumor papules in a patient treated for PCFCL. Based on this observation and on a review of the literature, we discuss the mechanism of this edematous reaction which does not seem to be allergic. Indeed, this focal reaction observed solely during the first infusion of rituximab is more likely linked with local cytokine release induced by B cell lysis in the skin. This reaction is neither unusual nor severe and should not lead to an interruption of rituximab.
Correlates of Delayed Recognition and Treatment of Acute Type A Aortic Dissection
Authors: Harris Kevin M. , Strauss Craig E. , Eagle Kim A. , Hirsch Alan T. , Isselbacher Eric M. , Tsai Thomas T. , Shiran Hadas , Fattori Rossella , Evangelista Arturo , Cooper Jeanna V. , Montgomery Daniel G. , Froehlich James B. , Nienaber Christoph A. ,   for the International Registry of Acute Aortic Dissection (IRAD) Investigators
Published: October 2011

Background—

In acute aortic dissection, delays exist between presentation and diagnosis and, once diagnosed, definitive treatment. This study aimed to define the variables associated with these delays.

Methods and Results—

Acute aortic dissection patients enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and January 2007 were evaluated for factors contributing to delays in presentation to diagnosis and in diagnosis to surgery. Multiple linear regression was performed to determine relative delay time ratios (DTRs) for individual correlates. The median time from arrival at the emergency department to diagnosis was 4.3 hours (quartile 1–3, 1.5–24 hours; n=894 patients) and from diagnosis to surgery was 4.3 hours (quartile 1–3, 2.4–24 hours; n=751). Delays in acute aortic dissection diagnosis occurred in female patients; those with atypical symptoms that were not abrupt or did not include chest, back, or any pain; patients with an absence of pulse deficit or hypotension; or those who initially presented to a nontertiary care hospital (all
P
<0.05). The largest relative DTRs were for fever (DTR=5.11;
P
<0.001) and transfer from nontertiary hospital (DTR=3.34;
P
<0.001). Delay in time from diagnosis to surgery was associated with a history of previous cardiac surgery, presentation without abrupt or any pain, and initial presentation to a nontertiary care hospital (all
P
<0.001). The strongest factors associated with operative delay were prolonged time from presentation to diagnosis (DTR=1.35;
P
<0.001), race other than white (DTR=2.25;
P
<0.001), and history of coronary artery bypass surgery (DTR=2.81;
P
<0.001).

Conclusions—

Improved physician awareness of atypical presentations and prompt transport of acute aortic dissection patients could reduce crucial time variables.
Wnt Signaling Mediates Pathological Vascular Growth in Proliferative Retinopathy
Authors: Chen Jing , Stahl Andreas , Krah Nathan M. , Seaward Molly R. , Dennison Roberta J. , Sapieha Przemyslaw , Hua Jing , Hatton Colman J. , Juan Aimee M. , Aderman Christopher M. , Willett Keirnan L. , Guerin Karen I. , Mammoto Akiko , Campbell Matthew , Smith Lois E.H.
Published: October 2011

Background—

Ischemic proliferative retinopathy, characterized by pathological retinal neovascularization, is a major cause of blindness in working-age adults and children. Defining the molecular pathways distinguishing pathological neovascularization from normal vessels is critical to controlling these blinding diseases with targeted therapy. Because mutations in Wnt signaling cause defective retinal vasculature in humans with some characteristics of the pathological vessels in retinopathy, we investigated the potential role of Wnt signaling in pathological retinal vascular growth in proliferative retinopathy.

Methods and Results—

In this study, we show that Wnt receptors (Frizzled4 and low-density lipoprotein receptor–related protein5 [Lrp5]) and activity are significantly increased in pathological neovascularization in a mouse model of oxygen-induced proliferative retinopathy. Loss of Wnt coreceptor Lrp5 and downstream signaling molecule dishevelled2 significantly decreases the formation of pathological retinal neovascularization in retinopathy. Loss of Lrp5 also affects retinal angiogenesis during development and formation of the blood-retinal barrier, which is linked to significant downregulation of tight junction protein claudin5 in
Lrp5
−/−
vessels. Blocking claudin5 significantly suppresses Wnt pathway–driven endothelial cell sprouting in vitro and developmental and pathological vascular growth in retinopathy in vivo.

Conclusions—

These results demonstrate an important role of Wnt signaling in pathological vascular development in retinopathy and show a novel function of Cln5 in promoting angiogenesis.
Low Birth Weight Infants Do Not Have Capillary Rarefaction at Birth
Authors: D'Souza Rohan , Raghuraman Rajendra P. , Nathan Preetha , Manyonda Isaac T. , Antonios Tarek F.T.
Published: October 2011

Low birth weight predicts adult essential hypertension and is linked to increased cardiovascular mortality in adult life. A reduction in capillary density (ie, rarefaction) is a hallmark of essential hypertension, and evidence suggests that rarefaction precedes the onset of the rise in blood pressure, because it is found in normotensive individuals at high risk of developing hypertension, suggesting that rarefaction is likely to be a primary structural abnormality. We hypothesized that low birth weight infants would have significant capillary rarefaction at birth. We studied 44 low birth weight infants born to normotensive mothers (33 were born preterm, birth weight: 1823±446 g; and 11 were born at term, birth weight: 2339±177 g) and compared them with 71 infants born at term with normal weight (birth weight: 3333±519 g). We used orthogonal polarized spectroscopy to measure basal (ie, functional) and maximal (ie, structural) skin capillary densities. Low birth weight infants, whether born preterm or at term, had significantly higher functional capillary density (mean difference of 10.5 capillaries per millimeter squared; 95% CI: 6.6–14.4 capillaries per millimeter squared;
P
<0.0001) and higher structural capillary density (mean difference of 11.1 capillaries per millimeter squared; 95% CI: 7.6–14.5 capillaries per millimeter squared;
P
<0.0001) when compared with normal weight term infants. We conclude that low birth weight infants born to normotensive mothers do not have capillary rarefaction at birth. These results contradict what might have been predicted from the concept of the intrauterine origins of adult disease and suggest that microcirculatory abnormalities observed in individuals of low birth weight occur in postnatal life rather than during their intrauterine existence.
Role of fiber/matrix interphases on dielectric, friction, and mechanical properties of glass fiber-reinforced epoxy composites
Authors: Kechaou B. , Salvia M. , Benzarti K. , Turki C. , Fakhfakh Z. , Tréheux D.
Published: October 2011

This study compares the mechanical, tribological, and dielectric properties of glass fiber-reinforced epoxy (GFRE), presenting various fiber/matrix adhesions. Three GFRE composites were studied. The only difference between them is in the initial preparation of fibers which is intentionally simplified compared to the complex sizings used in industry. Thus, fibers treated with aminosilane or silicone coupling agents were compared with fibers simply washed with deionized water.

The dielectric measurements show the leading role of interfacial bonding in the trapping or diffusion of electric charges. To obtain high mechanical properties, a fiber treatment that contributes to the diffusion of electric charges along the fiber/matrix interface is preferred. In addition, after friction, a modification of the dielectric properties in all materials is observed, and the trapping or the diffusion of the charges along the interfaces can make it possible to lower the friction coefficient, or the wear.
A novel approach for the three-point flexure test of multidirectional laminates
Authors: Mujika Faustino
Published: October 2011

The complementary energy of a multidirectional laminate is obtained as a function of mechanical and hygrothermal force and moment resultants. Three-point flexure is then analysed assuming that the specimen is in contact with the support rollers at four points. As this problem is statically indeterminate, the redundant force is obtained by applying Engesser's second theorem. Lift-off at supports is assumed to occur when the redundant unknown is zero. The displacement field of a multidirectional laminate in three-point flexure is then obtained by applying Engesser's first theorem, including transverse shear and hygrothermal effects. The displacements related to bending and twisting moments, hygrothermal effects and transverse shear forces are analysed separately.
Colombia’s New Left and the Challenges of Security
Authors: Rochlin James
Published: October 2011

Colombia’s democratic left faces four formidable but surmountable challenges in the realm of security: a hegemonic discourse of politics and security that is extremely right-wing, a persistent politics of fear, the security implications of the recent feeding frenzy for both legal and illicit transnational capital, especially with regard to labor and the strategic problems linked to contraband, and the consequences of former president Uribe’s success in quenching a thirst for order in the wake of the chaotic 1990s, including the colossal and growing U.S. strategic presence in the country.
Making Ends Meet
Authors: Edgell Penny , Ammons Samantha K. , Dahlin Eric C.
Published: October 2011

The “New Economy” features 24/7 employment, varied work schedules, job insecurity, and lower benefits and wages, which lead to disparities in experiences of security and sufficiency. This study investigates sufficiency concerns in the New Economy; who is having trouble making ends meet? Sufficiency concerns are subjective perceptions that work is insufficient to meet basic needs and that family and work cannot be coordinated in a stable way. This study uses the 2006 National Survey of Religion and Family Life ( N = 1,621) to analyze Americans’ experiences in the New Economy and how these experiences are related to work–family conflict. Sufficiency concerns were experienced by a quarter to a third of our respondents and were shaped by gender and structural inequality, especially race and education. Moreover, sufficiency concerns strongly predict work–family conflict, even when other controls are included. This research furthers our understanding of work–family conflict and the winners and losers in the New Economy.
Relics of Freedom
Authors: Bown Matthew
Published: October 2011

Artists today are on a collision course with religious sensibilities. Matthew Bown considers what happens when the cult of the body goes global
Art or Vandalism?
Authors: El Rashidi Yasmine
Published: October 2011

Street art has become one of the symbols of freedom in Cairo. Yasmine El Rashidi reports
Environmental decision making and an ecosystems approach
Authors: Fish Rob D.
Published: October 2011

This paper explores issues of theoretical design and application arising from ecosystem service based approaches to natural resource management. Conserving ecosystem services is now a key normative goal of environmental decision making, but the implications of embracing this concept are still little understood. In this paper I highlight two recurring and cross-cutting aspects of an ecosystems approach around which credible treatments of ecosystem services can be realized, not only in theory, but also in practice: first, the need to think ‘holistically’ about how any given project, proposal or plan would impact on service provision and human well-being; and, second, the need to manage ecosystem services in relation to wider stakeholder values, needs and priorities. While thinking about decision making from the perspective of ecosystem services is no panacea for sustainability, the paper points to a number of social science issues that interdisciplinary researchers could usefully address in these two contexts if they are to harness this concept in creative and critically engaged ways.
Integrating sciences to sustain urban ecosystem services
Authors: Lundy L. , Wade R.
Published: October 2011

Effective water management within urban settings requires robust multidisciplinary understanding and an appreciation of the value added to urban spaces by providing multifunctional green-blue spaces. Multifunctional landscapes where ecosystem service provisions are ‘designed-in’ can help ‘transition’ cities to more sustainable environments which are more resilient to changing future conditions. With benefits ranging from the supply of water, habitat and energy to pollutant removal, amenity and opportunities for recreation, urban water bodies can provide a focal point for reconnecting humans and nature in otherwise densely built-up areas. Managing water within urban spaces is an essential infrastructure requirement but has historically been undertaken in isolation from other urban functions and spatial requirements. Increasingly, because of the limits of space and need to respond to new drivers (e.g. mitigation of diffuse pollution), more sustainable approaches to urban water management are being applied which can have multiple functions and benefits. This paper presents a review of ecosystem services associated with water, particularly those in urban environments, and uses the emerging language of ecosystem services to provide a framework for discussion. The range of supporting, provisioning, regulating and cultural ecosystem services associated with differing types of urban water bodies are identified. A matrix is then used to evaluate the results of a series of social, ecological and physical science studies co-located on a single stretch of a restored urban river. Findings identify the benefits of, but also barriers to, the implementation of a transdisciplinary research approach. For many, transdisciplinary research still appears to be on the edge of scientific respectability. In order to approach this challenge, it is imperative that we bring together discipline specific expertise to address fundamental and applied problems in a holistic way. The ecosystem services approach offers an exciting mechanism to support researchers in tackling research questions that require thinking beyond traditional scientific boundaries. The opportunity to fully exploit this approach to collaborative working should not be lost.
Environmental sustainability
Authors: Ekins Paul
Published: October 2011

This paper reflects on the extensive literature on environmental sustainability that has been produced over the last two decades, and proposes a new approach for environmental policy that goes beyond the cost-benefit analysis that has proved so difficult to implement for non-marginal environmental issues. This approach combines the Safe Minimum Standard approach, which was proposed many years ago, with the concepts of environmental functions and ecosystem goods and services, which have been developed much more recently. It is shown that this approach provides the basis for a robust calculation of sustainability across different environmental themes, following which a ‘sustainability gap’, showing the extent to which this standard is not being met, may be computed. This gap may be expressed in both physical and monetary terms, which permits the formulation of sustainability performance in a scientifically robust, easily communicable indicator that may be compared with GDP. While there appear to be no insurmountable scientific or practical obstacles to the full operationalization of this approach, it remains to be seen whether human societies are sufficiently concerned about the implications of continuing environmental unsustainability to make the resources available for such operationalization, and to enact the policies to allow the sustainability standards to be met.
In Vivo Analysis of Coracoclavicular Ligament Kinematics During Shoulder Abduction
Authors: Izadpanah Kaywan , Weitzel Elizabeth , Honal Matthias , Winterer Jan , Vicari Marco , Maier Dirk , Jaeger Martin , Kotter Elmar , Hennig Jürgen , Weigel Matthias , Südkamp Norbert P.
Published: October 2011

Background: Anatomic reconstruction of the coracoclavicular ligaments for the treatment of acromioclavicular joint separations provides superior biomechanical stability compared with other procedures. Clavicular and coracoidal footprints of the conoid ligament (CL) and the trapezoid ligament (TL) are well described. So far, little is known about their kinematics and the changes of the coracoclavicular distance during shoulder abduction.

Hypothesis: The coracoclavicular distance along the coracoclavicular ligaments changes significantly with shoulder abduction and weightbearing.

Study Design: Descriptive laboratory study.

Methods: With use of an open magnetic resonance imaging scanner, the shoulders of 13 healthy volunteers were examined in supine and sitting positions. Three-dimensional magnetic resonance images of the shoulders were obtained in 30° increments of abduction (0°-120°). A manual segmentation of the scapula, the clavicle, and the coracoclavicular ligaments was performed. The insertion points of the coracoclavicular ligaments were identified, and automated measures along the ligamentous course were carried out.

Results: During transfer from the lying to sitting position, the coracoclavicular distance showed significant lengthening of 3 mm along the center of the CL, which significantly increased another 3 mm during shoulder abduction to a total lengthening of 6 mm. In the supine position, the coracoclavicular distance along the TL did not elongate significantly. In the sitting position, the distance along the medial portion of the TL shortened significantly, whereas the distance along the center portion did not elongate significantly during shoulder abduction.

Conclusion: The distances between the coracoclavicular insertion points depend on both patient and shoulder positioning. To prevent overconstraining of the graft, the CL should be fixated during 90° to 120° of shoulder abduction in a sitting position. Isometric reconstruction of the TL can be achieved if precise fixation of the graft at the centers of the conoidal and clavicular footprints is performed.
Assessment and Management of Sport-Related Concussions in United States High Schools
Authors: Meehan William P. , d’Hemecourt Pierre , Collins Christy L. , Comstock R. Dawn
Published: October 2011

Background: Little existing data describe which medical professionals and which medical studies are used to assess sport-related concussions in high school athletes.

Purpose: To describe the medical providers and medical studies used when assessing sport-related concussions. To determine the effects of medical provider type on timing of return to play, frequency of imaging, and frequency of neuropsychological testing.

Study Design: Descriptive epidemiology study.

Methods: All concussions recorded by the High School Reporting Information Online (HS RIO) injury surveillance system during the 2009 to 2010 academic year were included. χ2 analyses were conducted for categorical variables. Fisher exact test was used for nonparametric data. Logistic regression analyses were used when adjusting for potential confounders. Statistical significance was considered for P < .05.

Results: The HS RIO recorded 1056 sport-related concussions, representing 14.6% of all injuries. Most (94.4%) concussions were assessed by athletic trainers (ATs), 58.8% by a primary care physician. Few concussions were managed by specialists. The assessment of 21.2% included computed tomography. Computerized neuropsychological testing was used for 41.2%. For 50.1%, a physician decided when to return the athlete to play; for 46.2%, the decision was made by an AT. After adjusting for potential confounders, no associations between timing of return to play and the type of provider (physician vs AT) deciding to return the athlete to play were found.

Conclusion: Concussions account for nearly 15% of all sport-related injuries in high school athletes. The timing of return to play after a sport-related concussion is similar regardless of whether the decision to return the athlete to play is made by a physician or an AT. When a medical doctor is involved, most concussions are assessed by primary care physicians as opposed to subspecialists. Computed tomography is obtained during the assessment of 1 of every 5 concussions occurring in high school athletes.
The effect of folic acid as an antioxidant on the hypothalamic monoamines in experimentally induced hypothyroid rat
Authors: Ibrahim Wafaa , Tousson Ehab , El-Masry Thanaa , Arafa Nadia , Akela Mohamed
Published: October 2011

Thyroid hormones are recognized as key metabolic hormones that play a critical role in the central nervous system development throughout life. In the present study, we studied the biochemical changes of hypothalamus of hypothyroid rats at post-pubertal stage, and the possible ameliorating effect of folic acid. A total of 50 male albino rats were equally divided into five groups; the first and second groups were the control and folic acid groups, respectively, while the third group was the hypothyroid group in which rats received daily 6- n-propyl-2-thiouracil (PTU) in drinking water for 6 weeks to induce hypothyroidism. The fourth and fifth groups were hypothyroid rats treated with folic acid for 4 weeks during and after receiving PTU, respectively, and were dissected after 6 and 10 weeks, respectively. There was a significant increase in plasma total homocysteine, malondialdehyde (MDA), oxidized glutathione\reduced glutathione and total nitric oxide and hypothalamic MDA, serotonin and norepinephrine in the hypothyroid rats group as compared to the control group. This reflects hyperhomocysteinaemia and oxidative stress associated with hypothyroid state. On the other hand, hypothalamic total nitric oxide and dopamine in the hypothyroid rats group were significantly decreased when compared to the control group. Treatment of hypothyroid rats with folic acid improves the oxidative stress and hypothalamic monoamines. Our results revealed that, folic acid treatment was better if it is administered as an adjuvant after returning to the euthyroid state.
The Demographic, Clinical, and Magnetic Resonance Imaging (MRI) Features of Transverse Myelitis in Children
Authors: Thomas Terrence , Branson Helen M. , Verhey Leonard H. , Shroff Manohar , Stephens Derek , Magalhaes Sandra , Banwell Brenda
Published: October 2011

The authors collected demographic, clinical, and neuroimaging data prospectively on 38 children with transverse myelitis. One child died during the illness. The female:male ratio was 1.2:1 for children under age 10 years and 2.6:1 over age 10 years. Twenty-eight (74%) reported a prodromal event. Twenty-two patients (58%) had longitudinally extensive transverse myelitis, 9 (24%) had focal lesions, and 5 (13%) had both. Twenty of 33 with brain imaging (61%) had brain lesions; 7 fulfilled McDonald criteria for dissemination in space. Seven of 22 (36%) tested had cerebrospinal fluid oligoclonal banding, 6 of whom had brain lesions. Serum neuromyelitis optica IgG antibodies were absent in all 20 of the children for whom this test was available. At follow-up (mean 3.2 ± 2.0 years), 16% are wheelchair-dependent, 22% have persisting bladder dysfunction, and 13% have been diagnosed with multiple sclerosis.
Miller-Fisher Syndrome in Association With Enterovirus Infection
Authors: Moustaki Maria , Gika Artemis , Fretzayas Andrew , Voutsioti Aikaterini , Yiallouros Panagiotis , Karpathios Themistocles
Published: October 2011

Miller-Fisher is a rare syndrome of childhood that presents with external ophthalmoplegia, ataxia, and areflexia. It has been mainly associated with a preceding Campylobacter infection and less commonly with other bacterial or viral infections. This report describes, for the first time, a child with Miller-Fisher syndrome and documented Enterovirus infection, as it was proven by the isolation of Enterovirus from cerebrospinal fluid by polymerase chain reaction testing.
Thermal and mechanical buckling of sandwich plates with FGM face sheets resting on the Pasternak elastic foundation
Authors: Kiani Y , Bagherizadeh E , Eslami M R
Published: October 2011

Instability of sandwich plates with functionally graded material (FGM) face sheets, which are in contact with elastic foundation and subjected to thermal or mechanical loading, is considered. The derivation of equations is based on the first-order shear deformation plate theory. It is assumed that the thermo-mechanical non-homogeneous properties of FGM layers vary smoothly by distribution of power law across the plate thickness. Using the non-linear strain–displacement relations, the equilibrium and stability equations of sandwich plates are derived. The boundary conditions for the plate are assumed to be simply supported in all edges. The elastic foundation is modelled by the two parameters Pasternak model, which is obtained by adding a shear layer to the Winkler model. Closed-form solutions are presented to calculate the critical buckling load or temperature, which are useful for engineers in design. The effects of the foundation parameters, sandwich plate dimensions, and power law index of the FGM layers are presented comprehensively for the thermo-mechanical buckling of sandwich plates.
Theory analysis of the steady-state surface temperature on rolling tire
Authors: Li Y , Zuo S , Duan X , Guo X , Jiang C
Published: October 2011

The mechanisms of heat generation and heat dissipation of tire are first discussed, and the heat generation capacity and the heat dissipation capacity per unit time are obtained through the analysis of both tire contact pressure distribution and heat dissipation method. Then,according to heat balance condition of tire, the theory model of the steady-state surface temperature of tire is established based on tire temperature field tests. Finally, the effects of speed, load, and tire pressure on the steady-state surface temperature of tire are analysed. The results show that the established model of the steady-state surface temperature of rolling tire is feasible, and the results can reflect the thermal conditions of tire, and therefore provides a theoretical foundation to predict the steady-state surface temperature for various types of tires under different driving conditions.
Research of load identification based on multiple-input multiple-output SVM model selection
Authors: Mao W , Tian M , Yan G
Published: October 2011

In this article, the problem of multiple-input multiple-output (MIMO) load identification is addressed. First, load identification is proved in dynamic theory as non-linear MIMO black-box modelling process. Second, considering the effect of hyper-parameters in small-size sample problem, a new MIMO Support Vector Machine (SVM) model selection method based on multi-objective particle swarm optimization is proposed in order to improve the identification's performance. The proposed method treats the model selection of MIMO SVM as a multi-objective optimization problem, and leave-one-out generalization errors of all output models are minimized simultaneously. Once the Pareto-optimal solutions are found, the SVM model with the best generalization ability is determined. The proposed method is evaluated in the experiment of dynamic load identification on cylinder stochastic vibration system, demonstrating its benefits in comparison to the existing model selection methods in terms of identification accuracy and numerical stability, especially near the peaks.
A comprehensive dynamic model of electric overhead cranes and the lifting operations
Authors: Niu C M , Zhang H W , Ouyang H
Published: October 2011

The design of electric cranes requires knowledge of not only the dynamic loads acting on the mechanisms and the structure, and the movement of the crane and payload during their various operations, but also the electromagnetic characteristics of the control system. This article puts forward a new comprehensive dynamic model for the whole system of electric cranes, which includes the mechanisms, the steel structure, the induction motors, and their drive systems. A general electric overhead travelling crane controlled by two types of control schemes (of changing the rotor resistance and the closed-loop rotor-flux-oriented vector control) during the operation of its lifting mechanism is studied. Hamilton's principle with a modified Lagrangian, and the theory of induction motors and drive systems are combined to build a dynamic model of electric cranes during lifting operations. This model aims at simulating the dynamic behaviour of the mechanical and structural systems for the transient and steady-state behaviour of the induction motors and their control during the operations of a real crane. It can be seen that the dynamic system of the whole crane is highly non-linear and non-stationary even for only the lifting operation.
Active vibration control experiments on an AgustaWestland W30 helicopter airframe
Authors: Mottershead J E , Tehrani M Ghandchi , James S , Court P
Published: October 2011

This article describes the practical application of a vibration control technique, developed by the authors and known as the receptance method, to the AgustaWestland W30 helicopter airframe in the vibration test house at Yeovil. The experimental work was carried out over a total of 5 days in two visits to the Yeovil site during February and March 2011. In the experiments, existing electro-hydraulic actuators were used; they were built into the airframe structure and originally designed for vibration suppression by the methodology known as active control of structural response developed at the AgustaWestland Helicopters site in Yeovil. Accelerometers were placed at a large number of points around the airframe and an initial open-loop modal test was carried out. In a subsequent test, at higher actuator input voltage, considerable non-linearity was discovered, to the extent that the ordering of certain modes had changed. The vibration modes were, in general, heavily damped. Control was implemented using measured frequency response functions obtained at the higher input level. After acquiring the necessary measurements, simulations were carried out and the controller was implemented using MATLAB/Simulink and dSPACE. The closed-loop poles were mostly assigned with small real parts so that the system would be lightly damped and sharp peaks would be clearly apparent in the measured closed-loop frequency response functions. Locations of the open- and closed-loop poles in the complex s-plane were obtained to verify that the required assignment of poles had taken place.
Efficiency enhancement in a meso-Wankel compressor with overflow
Authors: Zhang Y L , Wang W
Published: October 2011

Given current environment protection problems, improvement of energy utilization efficiency is a major focus of compressor research. The presence of high-pressure gas in the clearance volume has an important effect on the efficiency of a Wankel compressor. Overflow pertains to the method that fully utilizes the high-pressure gas in the clearance volume. This method is used in this study, and its effect on the performance of a Wankel compressor is analysed by theoretical and simulation analyses. Compressor performance remains at a high level when the ratio of overflow recess volume to the clearance volume is approximately 2 per cent according to this study. Cooling capacity is improved by about 28 per cent compared with the Wankel compressor without overflow, and the relative deviation between the theoretical and the simulation results is kept within reasonable bounds.
Design of a single-DOF kinematic chain using hybrid GA-pattern search and sequential GA
Authors: Maheri A , Isikveren A T
Published: October 2011

With the aim of obtaining an optimal design for a single-DoF kinematic chain with the function of morphing aerofoils, two search methods are developed. The assessment criteria arethe length of the linkage and the accuracy of mapping. While the former is taken as the objective of optimization, the latter is treated as a constraint. The accuracy in mapping is measured by the aerodynamic performance deviation, a parameter defined by combining the geometric deviation and a weighting function based on the distribution of pressure coefficient. The first search method is based on a genetic algorithm (GA) with an embedded pattern search algorithm. The aim of the pattern search is to reduce the number of failed attempts in generating feasible solutions for the initial population of the GA as well as repairing infeasible individuals produced by reproduction operators. In the second search method, the set of design variables is determined in two consecutive steps by employing a sequential GA. Results of five runs of each search method reveal that while the best solution was produced by the sequential GA search method, hybrid GA-pattern search yielded more consistent results with shorter lengths and better mapping precision in average.
Strategies to minimize the fuel consumption of passenger cars during car-following scenarios
Authors: Li S Eben , Peng H
Published: October 2011

The way in which a vehicle is driven significantly affects its fuel consumption. This paper analyses the fuel-optimal driving strategies of a traditional vehicle equipped with a continuously variable transmission in car-following scenarios. A minimal-fuel-consumption problem is formulated, which is numerically solved using the Gauss pseudospectral method. The identified optimal manoeuvres were found to demonstrate two types of behaviour depending on the vehicle speed: pulse-and-gliding (PnG) and constant speed (CS). Further analyses indicate that the difference in behaviours mainly depends on the engine fuelling characteristics (both static and transient) and the road load. As the preceding vehicle’s speed increases, the optimal manoeuvre changes from partial PnG to full PnG, and finally to CS. In the full-PnG strategy, the engine switches between the minimum brake specific fuel consumption point and the idling point while the range error oscillates between its upper and lower bounds. The period, duty cycle percentage, and fuel economy improvement of the PnG strategy are analysed and presented.
A model-based methodology to predict the compressor behaviour for the simulation of turbocharged engines
Authors: Taburri M , Chiara F , Canova M , Wang Y-Y
Published: October 2011

Modelling the flow and efficiency of turbochargers for engine system simulation and control applications is an established practice that relies on the steady-state maps provided by manufacturer suppliers. However, as often occurs in practice, only a limited fraction of data is available in the compressor and turbine operating domain. For this reason, several modelling techniques have been proposed to interpolate and extrapolate flow and efficiency data. Most of the modelling approaches, based on black- or grey-box approaches, have limited predictive ability and typically low accuracy in off-design conditions, such as at engine idle or low engine speed. The current paper presents a novel model-based approach for overcoming the sparse nature of the available compressor maps, characterizing the flow and efficiency outputs of automotive centrifugal compressors by using extrapolation methods that are physically consistent with the conservation principles and actual behaviour of the system. The approach relies on a predictive model based on the thermodynamic analysis of a centrifugal compressor stage. The model builds upon the mass, energy, and entropy balance equations for compressible fluids. Specific sub-models are then introduced to account for the effects of slip phenomena, incidence losses, friction, and heat transfer losses, leading to high fidelity and predictive ability in off-design conditions. A detailed analysis of the model calibration and validation process is presented, utilizing data from two different automotive compressors. Finally, the procedure described is applied to characterize the compressor performance in engine system simulation, in comparison with a conventional (data-driven) model.
Regulated and unregulated emissions from a spark-ignition engine fuelled with low-blend ethanol–gasoline mixtures
Authors: Liu F-J , Liu P , Zhu Z , Wei Y-J , Liu S-H
Published: October 2011

The effects of ethanol addition to gasoline on the exhaust emissions (including regulated and unregulated emissions) and the conversion efficiencies of the three-way catalyst (TWC) were investigated in a three-cylinder spark-ignition (SI) gasoline engine. Three typical fuel blends – commercial 93# (Research Octane Number) gasoline (E0), E10, and E20 (with 0 per cent, 10 per cent, and 20 per cent ethanol in the blends by volume) – were used in the experiment. Unregulated emissions were measured by gas chromatography with a pulsed discharge helium ionization detector. Experimental results show that the regulated emissions of hydrocarbon, carbon monoxide, and nitrogen oxides decreased before and after the TWC with the increase of ethanol fraction in the fuel blends. However, the unregulated emissions of ethanol, acetaldehyde, and formaldehyde increased with the increase of ethanol fraction and decreased with increased engine speed and/or torque. Ethanol emission was not detected when fuelled with gasoline (E0). Ethanol emission was intensively influenced by the exhaust temperature and disappeared when the exhaust temperature was higher than 900 K for E10 and E20 operation. Acetaldehyde emission definitely comes from the oxidation of ethanol; the engine speed and load have opposite effects on acetaldehyde emission. Both ethanol and acetaldehyde can be converted effectively by the TWC. More formaldehyde was emitted at higher engine speed and lower load operating conditions.