974 resultados para Combined loading of axial compression and torsion


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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We use data from about 700 GPS stations in the EuroMediterranen region to investigate the present-day behavior of the the Calabrian subduction zone within the Mediterranean-scale plates kinematics and to perform local scale studies about the strain accumulation on active structures. We focus attenction on the Messina Straits and Crati Valley faults where GPS data show extentional velocity gradients of ∼3 mm/yr and ∼2 mm/yr, respectively. We use dislocation model and a non-linear constrained optimization algorithm to invert for fault geometric parameters and slip-rates and evaluate the associated uncertainties adopting a bootstrap approach. Our analysis suggest the presence of two partially locked normal faults. To investigate the impact of elastic strain contributes from other nearby active faults onto the observed velocity gradient we use a block modeling approach. Our models show that the inferred slip-rates on the two analyzed structures are strongly impacted by the assumed locking width of the Calabrian subduction thrust. In order to frame the observed local deformation features within the present- day central Mediterranean kinematics we realyze a statistical analysis testing the indipendent motion (w.r.t. the African and Eurasias plates) of the Adriatic, Cal- abrian and Sicilian blocks. Our preferred model confirms a microplate like behaviour for all the investigated blocks. Within these kinematic boundary conditions we fur- ther investigate the Calabrian Slab interface geometry using a combined approach of block modeling and χ2ν statistic. Almost no information is obtained using only the horizontal GPS velocities that prove to be a not sufficient dataset for a multi-parametric inversion approach. Trying to stronger constrain the slab geometry we estimate the predicted vertical velocities performing suites of forward models of elastic dislocations varying the fault locking depth. Comparison with the observed field suggest a maximum resolved locking depth of 25 km.

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Background Transcatheter aortic valve implantation (TAVI) is a treatment option for high-risk patients with severe aortic stenosis. Previous reports focused on a single device or access site, whereas little is known of the combined use of different devices and access sites as selected by the heart team. The purpose of this study is to investigate clinical outcomes of TAVI using different devices and access sites. Methods A consecutive cohort of 200 patients underwent TAVI with the Medtronic CoreValve Revalving system (Medtronic Core Valve LLC, Irvine, CA; n = 130) or the Edwards SAPIEN valve (Edwards Lifesciences LLC, Irvine, CA; n = 70) implanted by either the transfemoral or transapical access route. Results Device success and procedure success were 99% and 95%, respectively, without differences between devices and access site. All-cause mortality was 7.5% at 30 days, with no differences between valve types or access sites. Using multivariable analysis, low body mass index (<20 kg/m2) (odds ratio [OR] 6.6, 95% CI 1.5-29.5) and previous stroke (OR 4.4, 95% CI 1.2-16.8) were independent risk factors for short-term mortality. The VARC-defined combined safety end point occurred in 18% of patients and was driven by major access site complications (8.0%), life-threatening bleeding (8.5%) or severe renal failure (4.5%). Transapical access emerged as independent predictor of adverse outcome for the Valve Academic Research Consortium–combined safety end point (OR 3.3, 95% CI 1.5-7.1). Conclusion A heart team–based selection of devices and access site among patients undergoing TAVI resulted in high device and procedural success. Low body mass index and history of previous stroke were independent predictors of mortality. Transapical access emerged as a risk factor for the Valve Academic Research Consortium–combined safety end point.

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Silent corticotroph adenomas (SCA) are rare pituitary tumors with histologic hallmarks of corticotroph differentiation, including ACTH immunoreactivity, but lacking clinical evidence of Cushing's syndrome. We report on four female patients, aged 19-66 years, each presenting with a nonfunctional macroadenoma. Leading symptoms were headache in two cases and visual field deficits in one. One patient was incidentally diagnosed while undergoing cranial MRI for an unrelated condition. Three patients had marked obesity; none of them presented constitutional signs of Cushing's syndrome. Serum cortisol levels were moderately elevated in the two patients systematically tested in this respect. Marginal to moderate hyperprolactinemia was present in two cases. Two patients also were shown to be deficient in either gonadotroph or thyrotroph axis, while a third had a combined insufficiency of both gonadotroph and thyrotroph axis. MRI scans revealed intratumoral hemorrhage and/or cystic change in three cases, as well as tumor-related occlusive hydrocephalus in one. The latter patient was biopsied only, while the remaining underwent gross total resection. Histologically, all four lesions were diagnosed as SCA subtype I displaying intense immunoreactivity for ACTH. In three tumors, scattered cells coexpressed PRL as well. In addition, Crooke's hyaline change was noted in a significant number of tumor cells and in residual non-neoplastic corticotrophs in one case each. With MIB-1 labeling indices of 1-3%, none of the tumors qualified as atypical adenoma. We conclude that SCAs are more likely to be discovered as expansile tumors, whose advanced local space-occupying character at surgery rather than an inherently aggressive growth potential may negatively influence the clinical outcome. Subtle morphologic evidence of corticotroph suppression in residual pituitary adjacent to tumor lends further support to literature data indicating minimal or intermittent functional activity in this tumor type.

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Studies of subcellular Ca(2+) signaling rely on methods for labeling cells with fluorescent Ca(2+) indicator dyes. In this study, we demonstrate the use of single-cell electroporation for Ca(2+) indicator loading of individual neurons and small neuronal networks in rat neocortex in vitro and in vivo. Brief voltage pulses were delivered through glass pipettes positioned close to target cells. This approach resulted in reliable and rapid (within seconds) loading of somata and subsequent complete labeling of dendritic and axonal arborizations. By using simultaneous whole-cell recordings in brain slices, we directly addressed the effect of electroporation on neurons. Cell viability was high (about 85%) with recovery from the membrane permeabilization occurring within a minute. Electrical properties of recovered cells were indistinguishable before and after electroporation. In addition, Ca(2+) transients with normal appearance could be evoked in dendrites, spines, and axonal boutons of electroporated cells. Using negative-stains of somata, targeted single-cell electroporation was equally applicable in vivo. We conclude that electroporation is a simple approach that permits Ca(2+) indicator loading of multiple cells with low background staining within a short amount of time, which makes it especially well suited for functional imaging of subcellular Ca(2+) dynamics in small neuronal networks.

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Compared with the coronary setting, knowledge about antithrombotic therapies after endovascular treatment (EVT) is inadequate in patients with peripheral artery disease (PAD). Based on a review of trials and guidelines, which is summarized in this article, there is scant evidence that antithrombotic drugs improve outcome after peripheral EVT. To address this knowledge gap, the randomized, open-label, multinational edoxaban in patients with Peripheral Artery Disease (ePAD) study (ClinicalTrials.gov identifier NCT01802775) was designed to explore the safety and efficacy of a combined regimen of antiplatelet therapy with clopidogrel and anticoagulation with edoxaban, a selective and direct factor Xa inhibitor, both combined with aspirin. As of July 2014, 203 patients (144 men; mean age 67 years) from 7 countries have been enrolled. These patients have been allocated to once-daily edoxaban [60 mg for 3 months (or 30 mg in the presence of factors associated with increased exposure)] or clopidogrel (75 mg/d for 3 months). All patients received aspirin (100 mg/d) for the 6-month duration of the study. The primary safety endpoint is major or clinically relevant nonmajor bleeding; the primary efficacy endpoint is restenosis or reocclusion at the treated segment(s) measured at 1, 3, and 6 months using duplex ultrasound scanning. All outcomes will be assessed and adjudicated centrally in a masked fashion. The ePAD study is the first of its kind to investigate a combined regimen of antiplatelet therapy and anticoagulation through factor Xa inhibition with edoxaban.

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BACKGROUND: This observational research study investigated the association of cardiorespiratory fitness and weight status with repeated measures of 24-hr ambulatory blood pressure (24-hr ABP). Little is known about these associations and few data exist examining the interaction between cardiorespiratory fitness and weight status and the contributions of each on 24-hr ABP in youth. ^ METHODS: This research study used secondary analysis data from the "Adolescent Blood Pressure and Anger: Ethnic Differences" study. This current study sample included 374 African-American, Anglo-American, and Mexican-American adolescents 11-16 years of age. Mixed-effects models were used for testing the relationship between weight status and cardiorespiratory fitness and repeated measures of ambulatory blood pressure over 24 hours (24-hr ABP). Weight status was categorized into "normal weight" (BMI<85th percentile), "overweight" (85th≤BMI<95th), and "obese" (BMI≥95th). Cardiorespiratory fitness, determined by heart rate recovery (HRR), was defined as the difference between heart rate at peak exercise and heart rate at two minutes post-exercise, as measured by a height-adjusted step test and stratified into two groups: low and high fitness, using a median split. Ambulatory blood pressure (ABP) was monitored for a 24-hr period on a school day using the Spacelabs ambulatory monitor (Model 90207). Blood pressure and heart rate were recorded at 30 minute intervals throughout the day of recording and at 60 minute intervals during sleep. ^ RESULTS: No significant associations were found between weight status and mean 24-hr systolic blood pressure (SBP) or mean arterial pressure (MAP). A significant and inverse association between weight status and mean 24-hr diastolic blood pressure (DBP) was revealed. Cardiorespiratory fitness was significantly and inversely associated with mean 24-hr ABP. High fitness adolescents had significantly lower mean 24-hr SPB, DBP, and MAP measurements than low fitness adolescents. Compared to low fitness adolescents, high fitness adolescents had 1.90 mmHg, 1.16 mmHg, and 1.68 mmHg lower mean 24-hr SBP, DBP, and MAP, respectively. Additionally, high fitness appeared to afford protection from higher mean 24-hr SBP and MAP, irrespective of weight status. Among normal weight adolescents, low fitness resulted in higher mean 24-hr SBP and MAP, compared to their fit counterparts. Among adolescents categorized as high fitness, increasing weight status did not appear to result in higher mean 24-hr SBP or MAP. Cardiorespiratory fitness, rather than weight status, appeared to be a more dominant predictor of mean 24-hr SBP and MAP. ^ CONCLUSIONS: To our knowledge, this research is the first study to investigate the independent and combined contributions of cardiorespiratory fitness and weight status on 24-hr ABP, all objectively measured. The results of this study may potentially guide and inform future research. It appears that early cardiovascular disease (CVD) prevention should focus on improving cardiorespiratory fitness levels among all adolescents, particularly those adolescents least fit, regardless of their weight status, while obesity prevention efforts continue.^

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The combined effects of salinity, temperature and cadmium stress on survival and adaptation through cadmium-binding protein (CdBP) accumulation were studied in the grass shrimp, Palaemonetes pugio. In 96-hour bioassays, shrimp were exposed to zero or one of three levels of cadmium, under one of six different salinity (15, 25, or 35$\perthous$) and temperature (20 or 30$\sp\circ$C) regimes. CdBP concentrations were quantified in survivors from the 24 exposure groups. Salinity and temperature did not affect survivorship unless the shrimp were also exposed to cadmium. Grass shrimp were most sensitive to cadmium at low salinity-high temperature, and least sensitive at high salinity-low temperature. The incidence of cadmium-associated black lesions in gill tissue was influenced by salinity and temperature stress. P. pugio produced a 10,000 dalton metallothionein-like CdBP when exposed to at least 0.1 mg Cd$\sp{2+}$/L for 96 hours. Accumulation of CdBP was increased with increases in the exposure cadmium level, increases in temperature and decreases in salinity, independently and in conjunction with one another. Maximum CdBP concentrations occurred in grass shrimp that survived the salinity-temperature-cadmium conditions creating maximum stress as measured by highest mortality, not necessarily in shrimp exposed to the highest cadmium levels. The potential utility of this method as a monitor of physiological stress in estuarine biota inhabiting metal-polluted environments is discussed. ^

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This study investigated the combined effects of reduced pH and increased temperature on the capacities of the Pacific cupped oyster Crassostrea gigas to bioconcentrate radionuclide and metals. Oysters were exposed to dissolved radiotracers (110mAg, 241Am, 109Cd,57Co,54Mn, and 65Zn) at three pH (7.5, 7.8, 8.1) and two temperatures (21 and 24°C) under controlled laboratory conditions. Although calcifying organisms are recognized as particularly vulnerable to ocean acidification, the oyster did not accumulate differently the studied metals when exposed under the different pH conditions. However, temperature alone or in combination with pH somewhat altered the bioaccumulation of the studied elements. At pH 7.5, Cd was accumulated with an uptake rate constant twofold higher at 24°C than 21°C. Bioaccumulation of Mn was significantly affected by an interactive effect between seawater pH and temperature, with a decreased uptake rate at pH 7.5 when temperature increased (27 ± 1 vs. 17 ± 1 /day at 21 and 24°C, respectively). Retention of Co and Mn tended also to decrease at the same pH with decreasing temperature. Neither pH nor temperature affected strongly the elements distribution between shell and soft tissues. Significant effects of pH were found on the bioaccessibility of Mn, Zn, and 241Am during experimental in vitro simulation of human digestion.

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The effects of the combined use of long lactation periods (46 days) with alternative cages on the reproductive and growth performance of 104 rabbit does and their litters during five consecutive reproductive cycles were studied. Half of does were housed in conventional polyvalent cages (39 cm×100 cm×30 cm) and the other half in alternative polyvalent cages (39 cm×100 cm×60 cm), with a raised platform. Half of the rabbit does in each type of cage were weaned at 32 and the other half at 46 days after parturition. Longer lactation negatively affected the body weight (P<0.001), fat and energy content (P<0.05) of rabbit does at the end of the lactation period, but this effect decreased with the number of parturitions. Fertility, prolificacy and doe mortality were not affected by lactation length. Late weaning led to higher litter size (by 8.9%) and litter weight (by 11.3%) at the end of growing period (P<0.001) and lower feed conversion ratio per cage during the experimental period (13.5%) than weaning at 32 day (P<0.001). These results were paralleled by lower mortality (12.6 vs. 17.6%; P<0.01) of young rabbits weaned later during the overall experimental period. Differences in performance as a result of different weaning ages were only observed during cycles with worst health status (third and fifth cycles) in which late weaning decreased mortality. Type of cage did not affect doe body weight and body condition, mortality, fertility, prolificacy and litter size during the five reproductive cycles. Nevertheless, at day 21 litter weight and feed conversion ratio between 3 and 21 day were 4.2% higher (P<0.01) and 5.0% lower (P<0.05), respectively, in animals housed in alternative rather than in conventional cages. Alternative cages also led to heavier litters at 59 days (P<0.01). It was concluded that the combined use of longer lactations and cages with higher available surface with a raised platform could be alternatives to improve animal welfare in farmed rabbit.

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The effects of the combined use of long lactation periods (46 days) with alternative cages on the reproductive and growth performance of 104 rabbit does and their litters during five consecutive reproductive cycles were studied. Half of does were housed in conven- tional polyvalent cages (39 cm x 100 cm x 30 cm) and the other half in alternative polyvalent cages (39 cm x 100 cm x 60 cm), with a raised platform. Half of the rabbit does in each type of cage were weaned at 32 and the other half at 46 days after parturition. Longer lactation negatively affected the body weight ( P o 0.001), fat and energy content ( P o 0.05) of rabbit does at the end of the lactation period, but this effect decreased with the number of parturitions. Fertility, prolificacy and doe mortality were not affected by lactation length. Late weaning led to higher litter size (by 8.9%) and litter weight (by 11.3%) at the end of growing period ( P o 0.001) and lower feed conversion ratio per cage during the experimental period (13.5%) than weaning at 32 day ( P o 0.001). These results were paralleled by lower mortality (12.6 vs. 17.6%; P o 0.01) of young rabbits weaned later during the overall experimental period. Differences in performance as a result of different weaning ages were only observed during cycles with worst health status (third and fifth cycles) in which late weaning decreased mortality. Type of cage did not affect doe body weight and body condition, mortality, fertility, prolificacy and litter size during the five reproductive cycles. Nevertheless, at day 21 litter weight and feed conversion ratio between 3 and 21 day were 4.2% higher ( P o 0.01) and 5.0% lower ( P o 0.05), respectively, in animals housed in alternative rather than in conventional cages. Alternative cages also led to heavier litters at 59 days ( P o 0.01). It was concluded that the combined use of longer lactations and cages with higher available surface with a raised platform could be alternatives to improve animal welfare in farmed rabbit.

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Recent evidence suggests a potential role for thrombospondin-2 (TSP-2), a matricellular glycoprotein, in the regulation of primary angiogenesis. To directly examine the biological effect of TSP-2 expression on tumor growth and angiogenesis, human A431 squamous cell carcinoma cells, which do not express TSP-2, were stably transfected with a murine TSP-2 expression vector or with vector alone. A431 cells expressing TSP-2 did not show an altered growth rate, colony-forming ability, or susceptibility to induction of apoptosis in vitro. However, injection of TSP-2-transfected clones into the dermis of nude mice resulted in pronounced inhibition of tumor growth that was significantly stronger than the inhibition observed in A431 clones stably transfected with a thrombospondin-1 (TSP-1) expression vector, and combined overexpression of TSP-1 and TSP-2 completely prevented tumor formation. Extensive areas of necrosis were observed in TSP-2-expressing tumors, and both the density and the size of tumor vessels were significantly reduced, although tumor cell expression of the major tumor angiogenesis factor, vascular endothelial growth factor, was maintained at high levels. These findings establish TSP-2 as a potent endogenous inhibitor of tumor growth and angiogenesis.

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This study investigates the direct and indirect effects of financial participation (FP) and participation in decision-making (PDM) on employee job attitudes. The central premise is that both financial participation and participation in decision-making have effects on job attitudes, such as integration, involvement and commitment, perceived pay equity, performance-reward contingencies, satisfaction and motivation. After reviewing the theoretical and empirical literature and testing two theoretical frameworks, developed by Long (1978a) and Florkowski ( 1989), a new model was constructed to consider a combined effects of both FP and PDM, herein referred to as employee participation (EP). The underpinning of the model is based on the assumption that both ( a) the combination of financial participation and participation in decision-making ('employee participation'), and (b) participation in decision-making produce favourable effects on employee job attitudes. The test of the new model showed that employee participation does not produce more favourable effects on employee job attitudes, than does participation in decision-making on its own. The data were gathered from a questionnaire study administered in a large British retail organization that operates two types of ownership schemes - profit-sharing and SAYE schemes.