120 research outputs found
The increase in wave wake characteristics of marine vessels when accelerating
The waves generated by ships and boats (often referred to as wake wash, wave wake or simply wash) have been known to result in the erosion of riverbanks, damage to maritime structures, or be hazardous to other users of the waterway. The vast majority of research in this field to date has focused on the characteristics of these waves when the vessel is travelling at constant forward speed. Recent work by the authors has identified significant transient effects that occur while a vessel accelerates up to the desired operational speed, where both the height and period of the maximum wave generated are significantly greater than those generated at the corresponding steady-state speed. This notable increase in wave energy can be important, particularly where vessels are required to accelerate on a regular basis when operating in sheltered waterways with limited water depth. Common examples are commuter ferries that make regular passages between passenger terminals and hence pass through the transcritical speed zone to operate at supercritical speeds (in terms of depth Froude number).In this paper, a study into these transient effects through physical scale-model experimentation is expanded to include different hull forms, including a typical âlow washâ catamaran river ferry and a prismatic monohull. Results indicate that the increase in height of the maximum wave can exceed 80% and the period of this wave increase by more than 30% as a result of the acceleration phase compared to the steady-state speed. This poses the question whether these transient effects should form part of the assessment process when considering whether a vessel meets criteria imposed to regulate wash impacts.The same model scale data is also used to advise the model test community the required distance for a ship model to achieve a steady-state following the acceleration phase during model scale tests in facilities such as towing tanks or basins
Factors affecting greenhouse microclimate and its regulating techniques: a review
This paper reviews factors affecting greenhouse microclimate and its regulating techniques towards upgrading the greenhouse applications in the area of southeast China which have little or very basic technology integration. The microclimate of greenhouse is apparently influenced by the shape and its orientation, the wind direction, the property of covering material, and the use of insect-proof screen as they eventually affect the total solar radiation, the thermal characterises, and the flow pattern inside. The natural ventilation and sun block are the most common method to cool the greenhouse, but more efficient evaporative cooling such as pad-fan system, misting/fogging system and roof sprinkler are required with extreme temperatures. The earth to air heat exchanger and the heat storage using phase change material may be used for heating or cooling throughout the year which are more economic and energy-saving than other traditional thermal technologies. The reviewed knowledge provides insights into upgrading greenhouse applications in Ningbo area towards more sustainable and efficient greenhouse farming
Reversibility of Frailty After Bridge-to-Transplant Ventricular Assist Device Implantation or Heart Transplantation.
BACKGROUND: We recently reported that frailty is independently predictive of increased mortality in patients with advanced heart failure referred for heart transplantation (HTx). The aim of this study was to assess the impact of frailty on short-term outcomes after bridge-to-transplant ventricular assist device (BTT-VAD) implantation and/or HTx and to determine if frailty is reversible after these procedures. METHODS: Between August 2013 and August 2016, 100 of 126 consecutive patients underwent frailty assessment using Fried's Frailty Phenotype before surgical intervention: 40 (21 nonfrail, 19 frail) BTT-VAD and 77 (60 nonfrail, 17 frail) HTx-including 17 of the 40 BTT-VAD supported patients. Postprocedural survival, intubation time, intensive care unit, and hospital length of stay were compared between frail and nonfrail groups. Twenty-six frail patients were reassessed at 2 months or longer postintervention. RESULTS: Frail patients had lower survival (63 ± 10% vs 94 ± 3% at 1 year, P = 0.012) and experienced significantly longer intensive care unit (11 vs 5 days, P = 0.002) and hospital (49 vs 25 days, P = 0.003) length of stay after surgical intervention compared with nonfrail patients. Twelve of 13 frail patients improved their frailty score after VAD (4.0 ± 0.8 to 1.4 ± 1.1, P < 0.001) and 12 of 13 frail patients improved their frailty score after HTx (3.2 ± 0.4 to 0.9 ± 0.9, P < 0.001). Handgrip strength and depression improved postintervention. Only a slight improvement in cognitive function was seen postintervention. CONCLUSIONS: Frail patients with advanced heart failure experience increased mortality and morbidity after surgical intervention with BTT-VAD or HTx. Among those who survive frailty is partly or completely reversible underscoring the importance of considering this factor as a dynamic not fixed entity
Adorno?s Grey, Taussig?s Blue: Colour, Organization and Critical Affect
In this article we seek to open up the study of affect and organization to colour. Often simply taken for granted in organizational life and usually neglected in organizational thought, colour is an affective force by default. Deploying and interweaving the languages of affect theory, critical theory, and organization studies, we discuss colour as a primary phenomenon for the study of ?critical affect?. We then trace colour?s affect in conditioning the unfolding of organization in two particular ?colour/spaces? ? Adorno?s grey and Taussig?s blue of our title ? and discuss both its ambiguity and critical potential. Finally, we ponder what colour might do to the style of an organizational scholarship attuned to affect, where sentences blur with things and forces more than they seek to represent them
Transglutaminase 2 Undergoes a Large Conformational Change upon Activation
Human transglutaminase 2 (TG2), a member of a large family of enzymes that catalyze protein crosslinking, plays an important role in the extracellular matrix biology of many tissues and is implicated in the gluten-induced pathogenesis of celiac sprue. Although vertebrate transglutaminases have been studied extensively, thus far all structurally characterized members of this family have been crystallized in conformations with inaccessible active sites. We have trapped human TG2 in complex with an inhibitor that mimics inflammatory gluten peptide substrates and have solved, at 2-Ă
resolution, its x-ray crystal structure. The inhibitor stabilizes TG2 in an extended conformation that is dramatically different from earlier transglutaminase structures. The active site is exposed, revealing that catalysis takes place in a tunnel, bridged by two tryptophan residues that separate acyl-donor from acyl-acceptor and stabilize the tetrahedral reaction intermediates. Site-directed mutagenesis was used to investigate the acyl-acceptor side of the tunnel, yielding mutants with a marked increase in preference for hydrolysis over transamidation. By providing the ability to visualize this activated conformer, our results create a foundation for understanding the catalytic as well as the non-catalytic roles of TG2 in biology, and for dissecting the process by which the autoantibody response to TG2 is induced in celiac sprue patients
The Redox State of Transglutaminase 2 Controls Arterial Remodeling
While inward remodeling of small arteries in response to low blood flow, hypertension, and chronic vasoconstriction depends on type 2 transglutaminase (TG2), the mechanisms of action have remained unresolved. We studied the regulation of TG2 activity, its (sub) cellular localization, substrates, and its specific mode of action during small artery inward remodeling. We found that inward remodeling of isolated mouse mesenteric arteries by exogenous TG2 required the presence of a reducing agent. The effect of TG2 depended on its cross-linking activity, as indicated by the lack of effect of mutant TG2. The cell-permeable reducing agent DTT, but not the cell-impermeable reducing agent TCEP, induced translocation of endogenous TG2 and high membrane-bound transglutaminase activity. This coincided with inward remodeling, characterized by a stiffening of the artery. The remodeling could be inhibited by a TG2 inhibitor and by the nitric oxide donor, SNAP. Using a pull-down assay and mass spectrometry, 21 proteins were identified as TG2 cross-linking substrates, including fibronectin, collagen and nidogen. Inward remodeling induced by low blood flow was associated with the upregulation of several anti-oxidant proteins, notably glutathione-S-transferase, and selenoprotein P. In conclusion, these results show that a reduced state induces smooth muscle membrane-bound TG2 activity. Inward remodeling results from the cross-linking of vicinal matrix proteins, causing a stiffening of the arterial wall
Resposta broncodilatadora imediata ao formoterol em doença pulmonar obstrutiva crÎnica com pouca reversibilidade
Acute oxytocin improves memory and gaze following in male but not female nursery-reared infant macaques
Rationale: Exogenous oxytocin administration is widely reported to improve social cognition in human and nonhuman primate adults. Risk factors of impaired social cognition, however, emerge in infancy. Early interventionsâwhen plasticity is greatestâare critical to reverse negative outcomes.
Objective: We tested the hypothesis that oxytocin may exert similar positive effects on infant social cognition, as in adults. To test this idea, we assessed the effectiveness of acute, aerosolized oxytocin on two foundational social cognitive skills: working memory (i.e., ability to briefly hold and process information) and social gaze (i.e., tracking the direction of othersâ gaze) in 1-month-old nursery-reared macaque monkeys (Macaca mulatta). We did not predict sex differences, but we included sex as a factor in our analyses to test whether our effects would be generalizable across both males and females.
Results: In a double-blind, placebo-controlled design, we found that females were more socially skilled at baseline compared to males, and that oxytocin improved working memory and gaze following, but only in males.
Conclusions: These sex differences, while unexpected, may be due to interactions with gonadal steroids and may be relevant to sexually dimorphic disorders of social cognition, such as male-biased autism spectrum disorder, for which oxytocin has been proposed as a potential treatment. In sum, we report the first evidence that oxytocin may influence primate infant cognitive abilities. Moreover, these behavioral effects appear sexually dimorphic, highlighting the importance of considering sex differences. Oxytocin effects observed in one sex may not be generalizable to the other sex
Resposta a broncodilatador na espirometria: que parùmetros e valores são clinicamente relevantes em doenças obstrutivas?
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