139 research outputs found

    Production of PEG grafted PAN copolymers and their electrospun nanowebs as novel thermal energy storage materials

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    This paper deals with the synthesis of poly(ethylene glycol) (PEG) grafted poly(acrylo nitrile) (PAN) copolymers as novel solid-solid phase change materials via two step free radical polymerization reaction. The structural and thermal characterizations of the synthesized copolymers, namely PEG1500-g-PAN, PEG2000-g-PAN, PEG4000-g-PAN, PEG10000-g-PAN and PEG35000-g-PAN, were performed by Fourier transform infrared spectroscopy, Nuclear magnetic resonance spectrometry, differential scanning calorimetry and thermogravimetry. They were thermally stable and had the capability of absorbing and releasing great amount of heat ranging between 70 and 126 Jg-1 at the temperature interval of 40‒65 oC during heating and successive cooling cycles. To transform the PEG-g-PAN copolymers into the assemblies appropriate for thermal energy storage (TES) systems, thermo-regulating PEG-g-PAN nanowebs were also produced by means of coaxial electrospinning. The SEM images of PEG-g-PAN nanowebs displayed that they were all composed of hollow cylindrical ultrafine fibers with the average diameters ranging in 175‒277 nm. During the differential scanning calorimetry measurements, those nanowebs demonstrated repeatable solid-solid phase change with the heat storage capacities varying between 35 and 75 Jg-1 at the same temperature interval with the corresponding PEG-g- PAN copolymers. The PEG-g-PAN copolymers and their electrospun nanowebs can be promising TES materials and can have convenient industrial applications

    Northerners and Southerners Differ in Conflict Culture

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    The present study uses regression analysis of existing cross-national data sets to demonstrate that ingroup-outgroup discrimination and intergroup conflict management vary more along the north-south (latitudinal) axis than along the east-west axis of the Earth. Ingroup favoritism, outgroup rejection, political oppression, legal discrimination, and communication bullying are all less prevalent among Northerners than among Southerners in the Northern Hemisphere, but more prevalent among Northerners than among Southerners in the Southern Hemisphere. These findings provide a rich source for further research into how social conflicts are habitually experienced and handled by residents of northern versus southern habitats. A supplementary analysis specifies the extent to which ecological stressors-thermal stress, hydraulic stress, pathogenic stress, and subsistence stress-help explain why there are oppositely sloping north-south gradients of conflict culture above and below the equator. Taken in total, these results demonstrate the importance of considering latitude in forming a deeper understanding of conflict management and negotiation

    The associations between sedentary behaviour and mental health among adolescents:A systematic review

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    Background: With technological developments and modernised sedentary lifestyles has come an increase in diseases associated with inactivity such as obesity and other non-communicable diseases. Emerging evidence suggests that time spent sedentary may also interact with mental health. This systematic review examined the associations between sedentary behaviour and mental health problems among adolescents. Methods: This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, and applied a quality assessment tool for quantitative studies to identity best available evidence. Following stringent search strategy of the databases; Cumulative Index to Nursing and Allied Health Literature, Global Health, Health Source: Nursing and Academic Edition, MEDLINE, PsychARTICLES and PsycINFO, we identified 32 articles eligible for review. Results: All studies reported leisure screen time among adolescents, and two thirds of identified studies examined depressive symptomatology. Other mental health measures were; anxiety symptoms, self-esteem, suicide ideation, loneliness, stress, and psychological distress. Strong consistent evidence was found for the relationship between both depressive symptomatology and psychological distress, and time spent using screens for leisure. Moderate evidence supported the relationship between low self-esteem and screen use. Poorer mental health status was found among adolescents using screen time more than 2-3 h per day, and gender differences exist. Essential information was missing for quality of evidence including heterogeneity in mental health and screen time-based measures, and self-report data collection methods. Conclusions: The findings are of particular significance given the global public health concern of lifestyle-attributed diseases and the possibility for novel approaches to mental health. Future research should examine the psychological impact of reducing time spent using screens for leisure among adolescents, whilst accounting for possible confounding factors such as physical activity and dietary behaviours. It is critical that the reciprocal relationship between lifestyle behaviours and mental health is represented in both the psychiatric and public health forum

    Metabolic Syndrome and Cardiovascular Disease after Hematopoietic Cell Transplantation: Screening and Preventive Practice Recommendations from the CIBMTR and EBMT

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    Metabolic syndrome (MetS) is a constellation of cardiovascular risk factors that increases the risk of cardiovascular disease, diabetes mellitus, and all-cause mortality. Long-term survivors of hematopoietic cell transplantation (HCT) have a substantial risk of developing MetS and cardiovascular disease, with an estimated prevalence of MetS of 31% to 49% among HCT recipients. Although MetS has not yet been proven to impact cardiovascular risk after HCT, an understanding of the incidence and risk factors for MetS in HCT recipients can provide the foundation to evaluate screening guidelines and develop interventions that may mitigate cardiovascular-related mortality. A working group was established through the Center for International Blood and Marrow Transplant Research and the European Group for Blood and Marrow Transplantation with the goal to review literature and recommend practices appropriate to HCT recipients. Here we deliver consensus recommendations to help clinicians provide screening and preventive care for MetS and cardiovascular disease among HCT recipients. All HCT survivors should be advised of the risks of MetS and encouraged to undergo recommended screening based on their predisposition and ongoing risk factors

    Effect of Systemic Hypertension With Versus Without Left Ventricular Hypertrophy on the Progression of Atrial Fibrillation (from the Euro Heart Survey).

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    Hypertension is a risk factor for both progression of atrial fibrillation (AF) and development of AF-related complications, that is major adverse cardiac and cerebrovascular events (MACCE). It is unknown whether left ventricular hypertrophy (LVH) as a consequence of hypertension is also a risk factor for both these end points. We aimed to assess this in low-risk AF patients, also assessing gender-related differences. We included 799 patients from the Euro Heart Survey with nonvalvular AF and a baseline echocardiogram. Patients with and without hypertension were included. End points after 1 year were occurrence of AF progression, that is paroxysmal AF becoming persistent and/or permanent AF, and MACCE. Echocardiographic LVH was present in 33% of 379 hypertensive patients. AF progression after 1 year occurred in 10.2% of 373 patients with rhythm follow-up. In hypertensive patients with LVH, AF progression occurred more frequently as compared with hypertensive patients without LVH (23.3% vs 8.8%, p = 0.011). In hypertensive AF patients, LVH was the most important multivariably adjusted determinant of AF progression on multivariable logistic regression (odds ratio 4.84, 95% confidence interval 1.70 to 13.78, p = 0.003). This effect was only seen in male patients (27.5% vs 5.8%, p = 0.002), while in female hypertensive patients, no differences were found in AF progression rates regarding the presence or absence of LVH (15.2% vs 15.0%, p = 0.999). No differences were seen in MACCE for hypertensive patients with and without LVH. In conclusion, in men with hypertension, LVH is associated with AF progression. This association seems to be absent in hypertensive women

    Progression From Paroxysmal to Persistent Atrial Fibrillation. Clinical Correlates and Prognosis

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    Objectives: We investigated clinical correlates of atrial fibrillation (AF) progression and evaluated the prognosis of patients demonstrating AF progression in a large population. Background: Progression of paroxysmal AF to more sustained forms is frequently seen. However, not all patients will progress to persistent AF. Methods: We included 1,219 patients with paroxysmal AF who participated in the Euro Heart Survey on AF and had a known rhythm status at follow-up. Patients who experienced AF progression after 1 year of follow-up were identified. Results: Progression of AF occurred in 178 (15%) patients. Multivariate analysis showed that heart failure, age, previous transient ischemic attack or stroke, chronic obstructive pulmonary disease, and hypertension were the only independent predictors of AF progression. Using the regression coefficient as a benchmark, we calculated the HATCH score. Nearly 50% of the patients with a HATCH score >5 progressed to persistent AF compared with only 6% of the patients with a HATCH score of 0. During follow-up, patients with AF progression were more often admitted to the hospital and had more major adverse cardiovascular events. Conclusions: A substantial number of patients progress to sustained AF within 1 year. The clinical outcome of these patients regarding hospital admissions and major adverse cardiovascular events was worse compared with patients demonstrating no AF progression. Factors known to cause atrial structural remodeling (age and underlying heart disease) were independent predictors of AF progression. The HATCH score may help to identify patients who are likely to progress to sustained forms of AF in the near future. \ua9 2010 American College of Cardiology Foundation

    ICAR: endoscopic skull‐base surgery

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    Abbau der Serummucoproteide durch Speichel

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    REGIONAL MYOCARDIAL FUNCTIONS IN WILSON'S DISEASE

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    WOS: 000317946500522
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