1,086 research outputs found

    Perpendicular momentum injection by lower hybrid wave in a tokamak

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    The injection of lower hybrid waves for current drive into a tokamak affects the profile of intrinsic rotation. In this article, the momentum deposition by the lower hybrid wave on the electrons is studied. Due to the increase in the poloidal momentum of the wave as it propagates into the tokamak, the parallel momentum of the wave increases considerably. The change of the perpendicular momentum of the wave is such that the toroidal angular momentum of the wave is conserved. If the perpendicular momentum transfer via electron Landau damping is ignored, the transfer of the toroidal angular momentum to the plasma will be larger than the injected toroidal angular momentum. A proper quasilinear treatment proves that both perpendicular and parallel momentum are transferred to the electrons. The toroidal angular momentum of the electrons is then transferred to the ions via different mechanisms for the parallel and perpendicular momentum. The perpendicular momentum is transferred to ions through an outward radial electron pinch, while the parallel momentum is transferred through collisions.Comment: 22 pages, 4 figure

    Hypercholesterolemia is associated with hyperactive cardiac mTORC1 and mTORC2 signaling

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    Nutritional excess and hyperlipidemia increase the heart’s susceptibility to ischemic injury. Mammalian target of rapamycin (mTOR) controls the cellular response to nutritional status and may play a role in ischemic injury. To explore the effect of hypercholesterolemia on cardiac mTOR signaling, we assessed mTOR signaling in hypercholesterolemic swine (HC) that are also susceptible to increased cardiac ischemia-reperfusion injury. Yucatan pigs were fed a high-fat/high-cholesterol diet for 4 weeks to induce hypercholesterolemia, and mTOR signaling was measured by immunoblotting and immunofluorescence in the non-ischemic left ventricular area. Total myocardial mTOR and raptor levels were markedly increased in the HC group compared to the normocholesterolemic group, and directly correlated with serum cholesterol levels. mTOR exhibited intense perinuclear staining in myocytes only in the HC group. Hypercholesterolemia was associated with hyperactive signaling upstream and downstream of both mTOR complexes, including myocardial Akt, S6K1, 4EBP1, S6 and PKC-alpha, increased levels of cardiac hypertrophy markers, and a trend toward lower levels of myocardial autophagy. Hypercholesterolemia can now be added to the growing list of conditions associated with aberrant mTOR signaling. Hypercholesterolemia produces a unique profile of alterations in cardiac mTOR signaling, which is a potential target in cardiac diseases associated with hypercholesterolemia and nutritional excess

    Effect of travel motivation on tourist satisfaction through the dimensions of destination image: The case of leisure urban tourism in Monterrey, Mexico

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    El tema de este trabajo es el efecto determinante de la motivación de viaje sobre la satisfacción del turista teniendo como variables mediadoras a los dos componentes de la imagen percibida del destino en un contexto de turistas de ocio a la ciudad de Monterrey, México. A través de un modelo de ecuaciones estructurales por medio de mínimos cuadrados parciales (PLS) fue posible la identificación de los principales indicadores observables de la motivación de viaje de los turistas y obtener evidencia de su papel causal predictivo sobre la satisfacción del turista. En dicha relación, dos componentes principales de la imagen demostraron un efecto mediador para los cuales igualmente quedaron establecidos sus indicadores observables, así como su relación causa – efecto. Con ello se pudo establecer qué aspectos de la motivación son los más importantes para los turistas y vincularlos con la satisfacción del turista y a su vez establecer aquellos aspectos (afectivos y cognitivos) mejor valorados en las percepciones sobre el destino. Finalmente, a modo de conclusión, se emiten recomendaciones generales para la gestión del producto turístico urbano.The subject of this research work is the effect of travel motivation on tourist satisfaction with the mediating variables being the two components of the destination’s perceived image in a context of leisure tourists to the city of Monterrey, Mexico. Through structural equation modeling by partial least squares (PLS) the identification of the main observable indicators of the travel motivation of tourists were identified and thus evidence of its determining role on tourist satisfaction was obtained. In this relationship, two main components of the image showed a mediator effect. The observable indicators of these components were also established as was their cause-effect relationship. Therefore, those aspects of motivation which are the most important for tourists and linked to tourist satisfaction were determined and those aspects (affective and cognitive) best valued in perceptions about the destination were also established. Finally, by way of conclusion, general recommendations for urban tourism product management are provided

    The paradoxical effects of somatostatin on the bioactivity and production of cytotoxins derived from human peripheral blood mononuclear cells.

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    Somatostatin (SMS), a naturally occurring peptide is known to inhibit the production of certain protein molecules and to diminish the ability of peripheral blood mononuclear cells to proliferate. We tested the effects of three forms of SMS on the bioactivity of both lymphotoxin (LT) and tumour necrosis factor (TNF). We also tested the effects of these agents on production of cytotoxins by peripheral blood mononuclear cells. We found the 28 amino acid form of SMS significantly enhanced the bioactivity of both LT and TNF (10(-9) M concentration) when tested in mouse L cells. The 14 amino acid form of SMS enhanced LT (10(-9) M concentration) activity but not TNF activity. The first 14 amino acid form of SMS-28 (amino terminal) did not affect bioactivity of the cytotoxin. In contrast, the naturally occurring 14 amino acid form of SMS (10(-8) M concentration) significantly diminished production of cytotoxin by human peripheral blood mononuclear cells. Cytotoxin produced by the latter was shown to be a combination of both LT and TNF. Similarly after SMS exposure, the cytotoxin produced remained a mixture of LT and TNF in roughly similar proportions. It thus appears that certain forms of SMS can enhance the bioactivity of cytotoxins, but at the same time decrease the production of these cytotoxins

    Lo studio internazionale multicentrico dell'Organizzazione Mondiale della Sanità sui disturbi psichici nella medicina generale: risultati relativi all'area di Verona

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    Objectives - To present the results obtained from a cross-sectional evaluation of a sample of primary care attenders selected in Verona in the framework of the World Health Organization International Multicentre Study on Psychological Problems in Primary Care Settings. Methods - Among consecutive attenders at 16 primary care clinics in Verona during the period April 1991/February 1992, a random sample, stratified on the basis of GHQ-12 scores, was selected for a thorough evaluation of psychological status, physical status and disability in occupational and other daily activities. All patients with psychopathological symptoms at baseline assessment and a 20% random sample of those without psychopathological symptoms were interviewed again after 3 and 12 months (data not presented here). Results - Overall, 1,656 subjects were approached at the primary care clinics and 1,625 met inclusion criteria. The screening procedure was completed by 1,558 subjects and the second-stage evaluation by 250. Psychiatric disorders according to ICD-10 criteria were diagnosed in 12.4% of consecutive primary care attenders; of these, about one-third (4.5% of consecutive primary care attenders) satisfied ICD-10 diagnostic criteria for two or more disorders. Current Depressive Episode (4.7%) and Generalized Anxiety Disorder (3.7%) were the most common diagnoses. In addition, 11.2% of consecutive primary care attenders had ‘sub-threshold' psychiatric disorders (i.e., they suffered from symptoms in at least two different areas among those listed in ICD-10, but they did not satisfy diagnostic criteria for well-defined disorders). Psychiatric disorders were more common among females and those aged 24-44 years. Only 20.6% of the subjects with psychiatric disorders contacted the general practitioner for their psychological symptoms, 5.7% complained of symptoms which might have had a psychological origin, whereas in about 70% of the cases the psychiatric disorder was concealed behind the presentation of somatic symptoms, pains in various parts of the body or chronic physical illness. Sixty-two percent of the subjects with psychiatric disorders rated their health status as fair or poor, as compared to 52.0% of those with chronic physical illness and 31.3% of those without such disorders. According to the general practitioner, 40.1% of the subjects with psychiatric disorders and 45.3% of those with chronic physical illness had a fair or poor health status, compared to 14.4% of those without such disorders. Disability in occupational and other daily activities was reported by 52.5% of the subjects with psychiatric disorders (in 40.1% of the cases disability was moderate or severe), 44.4% of those with chronic physical illness (in 26.8% of the cases disability was moderate or severe), and 15.0% of the subjects without such disorders (in 9.1% of the cases disability was moderate or severe). According to the interviewer, disability was identified in 48.4% of the subjects with psychiatric disorders, 39.0% of those with chronic physical illness, and 27.6% of the subjects without such disorders. Sixty per cent of the subjects with psychiatric disorders suffered from concurrent chronic physical illness; these subjects had a poorer health status and higher disability levels than those with psychiatric disorders only. Conclusions - Psychiatric disorders among primary care attenders are frequent and represents a major public health problem, since they entail severe functional limitations for the patients and high costs for the society. Thus, appropriate programs for their recognition and treatment are neede

    Phosphorylation and translocation of heat shock protein 27 and αB-crystallin in human myocardium after cardioplegia and cardiopulmonary bypass

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    ObjectivesCardiac surgery using cardioplegia and cardiopulmonary bypass subjects myocardium to hypothermic reversible ischemic injury that can impair cardiac function. Research in animal and cell models demonstrates that acute myocardial ischemia/reperfusion injury causes phosphorylation of heat shock protein 27 and αB-crystallin. Phosphorylation of heat shock protein 27 and αB-crystallin is implicated in the regulation of both beneficial and detrimental responses to ischemic injury. The phosphorylation status of these proteins in human myocardium after ischemic insults associated with cardioplegia and cardiopulmonary bypass is unknown.MethodsRight atrial appendage and chest wall skeletal muscle samples were collected from patients before and after cardioplegia and cardiopulmonary bypass. Cardioplegia and cardiopulmonary bypass-induced changes in phosphorylation and localization of heat shock protein 27 and αB-crystallin were determined using immunoblot and confocal microscopy with total and phospho-specific antibodies.ResultsCardioplegia and cardiopulmonary bypass increased the phosphorylation of heat shock protein 27 on serine 15, 78, and 82, and αB-crystallin on serine 59 and 45, but not serine 19. The majority of heat shock protein 27 and αB-crystallin localized to I-bands of cardiac myofilaments and shifted to a detergent insoluble fraction after cardioplegia and cardiopulmonary bypass. Cardioplegia and cardiopulmonary bypass–induced phosphorylation of specific heat shock protein 27 and αB-crystallin residues were associated with additional subcellular locations. Increases in phosphorylation of heat shock protein 27 and αB-crystallin were negatively correlated with cardiac function after surgery.ConclusionCardiac surgery using cardioplegia and cardiopulmonary bypass is associated with phosphorylation and myofilament translocation of heat shock protein 27 and αB-crystallin in human myocardium. Phosphorylation of specific heat shock protein 27 and αB-crystallin serine residues is associated with distinct localization. Understanding the human myocardial small heat shock protein response may have significant implications for surgical myocardial protection

    Surveillance of colonization and infection with Staphylococcus aureus susceptible or resistant to methicillin in a community skilled-nursing facility

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    Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen in acute care hospitals and long-term care facilities. Few studies have been reported in private skilled nursing facilities (SNFs) not experiencing outbreaks of infections caused by MRSA. METHODS: From a 149-bed SNF with no outbreaks, we report a 1-year prospective surveillance study of S. aureus colonization and infection, with focus on S. aureus phenotypes, both methicillin susceptible (MS) and methicillin resistant (MR). Nasal and stool or rectal screening cultures were done on admission, and all patients underwent screening on at least a quarterly basis for 1 year. RESULTS: Overall, 35% of patients were colonized at least once with S. aureus, (72% MS, 25% MR, and 3% mixed phenotypes), 94% of the MRSA were ciprofloxacin resistant. Nasal colonization with any S. aureus was more frequent, but 13% of patients had positive results only in rectal specimens. Twenty-one percent of the newly admitted and 15% of continuing patients acquired colonization during their stay in the SNE Colonization was transient or persistent, persisted longer in the nares compared with colonization in rectal specimens, and was more stable for methicillin-susceptible S. aureus. Nine percent of patients had development of infection with S. aureus. There was no indication that MRSA colonization led to more infections than methicillin-susceptible S. aureus. Of the 13 infected patients in whom cultures had previously been obtained, seven (54%) had been colonized by the same phenotype strains. CONCLUSIONS: In this private SNF, endemic S. aureus infections occur at a low frequency, reflecting a moderate level of colonization with S. aureus. However, a trend showing gradual increases in frequencies of colonization and infection is of concern and suggests that in this SNF, future intervention could become warranted

    Management of syncope: clinical and economic impact of a Syncope Unit

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    Aims Aim of this observational study is to evaluate the clinical performance of a Syncope Unit, in order to assess whether the implemented organization really improves syncope management. Methods and results The study enrolled patients with unexplained syncope who were consecutively referred to our Syncope Unit, either as outpatients or during hospitalization, in a 2-month period. The design of this observational study consists in three phases: a retrospective analysis of their clinical. management in the 9 months prior to the first attendance at the Syncope Unit (phase one), their subsequent clinical management in the Syncope Unit (phase two) and a 9-month follow-up (phase three). The retrospective analysis of phase one showed that 25% of patients had already been hospitalized without diagnosis. After Syncope Unit evaluation, diagnosis was obtained in 82% of patients, with 15% of patients indicated to pacing. In the follow-up, 23% of patients experienced a syncopal recurrence. Our analysis indicated an 85% reduction of hospital costs in the follow-up period. Conclusion The clinical and economic analysis of the three phases of our study demonstrates that a Syncope Unit allows an improved management of patients with syncope

    3D segmentation of intervertebral discs: from concept to the fabrication of patient-specific scaffolds

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    Aim: To develop a methodology for producing patient-specific scaffolds that mimic the annulus fibrosus (AF) of the human intervertebral disc (IVD) by means of combining magnetic resonance imaging (MRI) and 3D bioprinting. Methods: In order to obtain the AF 3D model from patientâ s volumetric MRI dataset, the RheumaSCORE segmentation software was used. Polycaprolactone scaffolds with three different internal architectures were fabricated by 3D bioprinting, and characterized by micro-computed tomography. Results: The demonstrated methodology of a geometry reconstruction pipeline enabled to successfully obtain an accurate AF model and 3D print patient-specific scaffolds with different internal architectures. Conclusion: The results guide us towards patient-specific IVD tissue engineering as demonstrated a way of manufacturing personalized scaffolds using patient's MRI data.The authors would like to acknowledge the financial support provided by the Portuguese Foundation for Science and Technology (FCT) through the project EPIDisc (UTAPEXPL/BBB-ECT/0050/2014), funded in the Framework of the ‘International Collaboratory for Emerging Technologies, CoLab’, UT justin|Portugal Program. FCT is also acknowledged for the PhD scholarship attributed to IF Cengiz (SFRH/ BD/99555/2014) and the financial support provided to J Silva-Correia (SFRH/BPD/100590/2014 and IF/00115/2015). JM Oliveira also thanks the FCT for the funds provided under the program Investigador FCT (IF/00423/2012 and IF/01285/2015). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.info:eu-repo/semantics/publishedVersio
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