364 research outputs found
Promoting the Flexibility of Thermal Prosumers Equipped with Heat Pumps to Support Power Grid Management
The increasing share of renewable energy sources in energy systems will lead to unpredictable moments of surplus/deficit in energy production. To address this issue, users with heat pumps can provide support to power grid operators through flexible unit operation achieved via Demand Response programs. For buildings connected to low-temperature heating networks with ensured third-party access, further room for flexibility can be explored by investigating the production of surplus heat that can be sold to the network. A key aspect lies in the identification of the energy pricing options that could encourage such flexible operation of a heat pump by “thermal prosumers”. To this aim, the present study investigates the impact of ad hoc variations in the electricity purchasing price through discounts or penalties included in the “network cost” component of the price on cost-effective operation of a heat pump connected to the thermal network. To discuss the effects of different pricing options in terms of increased flexibility, an office building located in Italy and equipped with a high-temperature heat pump is adopted as the case study. A heuristic profit-oriented management strategy of the heat pump is assumed, and dynamic simulations are performed. The results indicate that at current electricity prices, the heat pump operation is profitable both when supplying the heat to meet the building’s requirements and when producing surplus heat for sale to the thermal network. In addition, it is revealed that the penalties applied to the electricity purchasing price are effective in encouraging changes in the heat pump operation strategy, reducing its average production (the building increasingly relying on buying heat from the network) and the associated electricity consumption by 46.0% and 79.7% in the “light” and “severe” local power deficit scenarios, respectively
Knowledge, risk perception and behaviours in swimming pool users of Palermo city, Sicily
To assess knowledge, risk perception and behaviours of a sample of swimming pool users in Palermo. A total of 498 subjects were interviewed by self-administered anonymous questionnaire including socio-demographic questions, knowledge/risk perception and behaviours. Overall, 289 subjects (58%) had a mean of 1.9\ub11.2 healthy behaviours. Age older than 30 years (OR=0.46; 95% CI=0.26\u20130.81), female sex (OR=0.52; 95% CI=0.35\u20130.76) and a high knowledge score (OR=0.15; 95% CI=0.03\u20130.69) were significantly associated with having healthy behaviours in both univariate and multivariate analysis. Unhealthy behaviours can be frequently found in swimming pool bathers and, particularly, in some target groups. Public health prevention strategies should be implemented to improve public awareness and information on a safe use of recreational water environments
Carotid endarterectomy impairs blood pressure homeostasis by reducing the physiologic baroreflex reserve
ObjectiveTo assess the impact of carotid endarterectomy on blood pressure homeostasis and baroreflex function, with particular reference to the presence or absence of significant contralateral carotid artery disease, we conducted a prospective study in 80 patients with symptomatic extracranial carotid disease undergoing carotid endarterectomy in a regional teaching hospital over 2 years.MethodsPatients were divided into two groups: the control group (n = 37) had no significant contralateral carotid disease; patients in the diseased group (n = 23) had either >70% stenosis or occlusion of the contralateral carotid artery. Seventeen patients with abnormal heart rhythms, poor quality recordings, or with intermediate degrees of contralateral carotid stenosis were excluded. Three patients who had previously undergone contralateral carotid endarterectomy were separately evaluated. Atheromatous plaque was removed from carotid lumen and the baroreflex mechanism received direct intraoperative stimulation before and after carotid endarterectomy. The main outcome measures were (1) the hemodynamic response to the carotid endarterectomy, baroreflex sensitivity, and operating set point (the resting blood pressure, which the baroreflex mechanism maintains) before and after removal of the atheromatous plaque, and (2) the responsiveness of the ipsilateral baroreceptor mechanism to direct stimulation. The impact of the presence of contralateral carotid stenosis on these variables was also evaluated.ResultsPatients in the two groups were comparable for preoperative demographic, medication, and hemodynamic variables. Carotid endarterectomy led to a rise in mean arterial pressure from 81.3 ± 3.9 mm Hg to 103.5 ± 4.6 mm Hg (P < .00001) and from 87.6 ± 4.3 mm Hg to 94.0 ± 4.5 mm Hg (P < .003) in the diseased and control groups, respectively. The magnitude of blood pressure response was significantly greater in the diseased group than in the control group (P < .00001). This hypertensive shift was not accompanied by the expected fall in heart rate. Direct baroreflex stimulation prior to carotid endarterectomy caused a significantly greater response in the diseased group, suggesting sensitization of the ipsilateral carotid baroreceptor in the presence of contralateral carotid disease. Furthermore, the baroreflex response was obliterated after endarterectomy. There were significant reductions in baroreflex sensitivity and a hypertensive shift in the operating set point, the magnitude of which was significantly greater in patients with contralateral carotid disease.ConclusionsCarotid endarterectomy impairs blood pressure homeostasis through surgical destruction of the ipsilateral carotid baroreflex mechanism. Patients with contralateral carotid stenosis have a reduced baroreflex reserve and show greater baroreflex dysfunction and hemodynamic instability after endarterectomy. These patients are at greater risk of postendarterectomy complications and should be monitored closely
Algoritmos de derivaciĂłn y confirmaciĂłn diagnĂłstica de citologĂa cervical atĂpica: desafĂos para la actualizaciĂłn
IndexaciĂłn: ScieloEl Programa Nacional de Pesquisa y Control del Cáncer Cervicouterino de Chile ha contribuido al descenso sostenido de la mortalidad por cáncer de cuello uterino. Para la reducciĂłn de esta mortalidad ha sido fundamental la citologĂa exfoliativa del cĂ©rvix, la que no está exenta de resultados inciertos. En este sentido, los frotis clasificados como atĂpicos se consideran ambiguos por la presencia de anomalĂas celulares de difĂcil determinaciĂłn, lo que se traduce en un diagnĂłstico de probabilidad incierta. En la literatura nacional como internacional, se manifiesta un notorio interĂ©s por unificar la nomenclatura citolĂłgica cervical y los algoritmos de derivaciĂłn y confirmaciĂłn diagnĂłstica, para el manejo clĂnico de las mujeres con anomalĂas citolĂłgicas cervicales y lesiones precursoras de cáncer cervicouterino. Por lo anterior, se considera relevante los estudios que proporcionen evidencia clĂnica epidemiolĂłgica actualizada, que permitan optimizar el cumplimiento del Programa Nacional de Cáncer Cervicouterino, conducentes al logro de los Objetivos Sanitarios del perĂodo 2011-2020.The National Research and Control of Cervical Cancer in Chile had contributed to the sustained decline in mortality from cervical cancer. The exfoliative cytology of the cervix has been to reduce this mortality, which is not without uncertain results. The smears classified as atypical are considered ambiguous by the presence of cellular abnormalities difficult to determine, resulting in a diagnosis of uncertain probability. The literature, both nationally and internationally, is widespread interest to unify the nomenclature cervical cytology and the support of the derivation algorithms for the clinical management of women with cytologic abnormalities cervical and cervical cancer precursor lesions. Therefore, it is relevant to perform studies the provide updated epidemiological clinical evidence, to optimize the performance of the National Program for the achievement of health objectives for the period 2011-2020.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-75262012000400015&nrm=is
Thermal convection in fluidized granular systems
Thermal convection is observed in molecular dynamic simulation of a fluidized
granular system of nearly elastic hard disks moving under gravity, inside a
rectangular box. Boundaries introduce no shearing or time dependence, but the
energy injection comes from a slip (shear-free) thermalizing base. The top wall
is perfectly elastic and lateral boundaries are either elastic or periodic. The
observed convection comes from the effect of gravity and the spontaneous
granular temperature gradient that the system dynamically develops.Comment: 4 pages, 5 figure
Maternal-to-fetal allopurinol transfer and xanthine oxidase suppression in the late gestation pregnant rat.
Fetal brain hypoxic injury remains a concern in high-risk delivery. There is significant clinical interest in agents that may diminish neuronal damage during birth asphyxia, such as in allopurinol, an inhibitor of the prooxidant enzyme xanthine oxidase. Here, we established in a rodent model the capacity of allopurinol to be taken up by the mother, cross the placenta, rise to therapeutic levels, and suppress xanthine oxidase activity in the fetus. On day 20 of pregnancy, Wistar dams were given 30 or 100 mg kg(-1) allopurinol orally. Maternal and fetal plasma allopurinol and oxypurinol concentrations were measured, and xanthine oxidase activity in the placenta and maternal and fetal tissues determined. There were significant strong positive correlations between maternal and fetal plasma allopurinol (r = 0.97, P < 0.05) and oxypurinol (r = 0.88, P < 0.05) levels. Under baseline conditions, maternal heart (2.18 ± 0.62 mU mg(-1)), maternal liver (0.29 ± 0.08 mU mg(-1)), placenta (1.36 ± 0.42 mU mg(-1)), fetal heart (1.64 ± 0.59 mU mg(-1)), and fetal liver (0.14 ± 0.08 mU mg(-1)) samples all showed significant xanthine oxidase activity. This activity was suppressed in all tissues 2 h after allopurinol administration and remained suppressed 24 h later (P < 0.05), despite allopurinol and oxypurinol levels returning toward baseline. The data establish a mammalian model of xanthine oxidase inhibition in the mother, placenta, and fetus, allowing investigation of the role of xanthine oxidase-derived reactive oxygen species in the maternal, placental, and fetal physiology during healthy and complicated pregnancy
Dopamine transporter trafficking and Rit2 GTPase: Mechanism of action and in vivo impact
Following its evoked release, DA signaling is rapidly terminated by presynaptic reuptake, mediated by the cocaine-sensitive DAT. DAT surface availability is dynamically regulated by endocytic trafficking, and direct PKC activation acutely diminishes DAT surface expression by accelerating DAT internalization. Previous cell line studies demonstrated that PKC-stimulated DAT endocytosis requires both Ack1 inactivation, which releases a DAT-specific endocytic brake, and the neuronal GTPase, Rit2, which binds DAT. However, it is unknown whether Rit2 is required for PKC-stimulated DAT endocytosis in DAergic terminals, or whether there are region- and/or sex-dependent differences in PKC-stimulated DAT trafficking. Moreover, the mechanisms by which Rit2 controls PKC-stimulated DAT endocytosis are unknown. Here, we directly examined these important questions. Ex vivo studies revealed that PKC activation acutely decreased DAT surface expression selectively in ventral, but not dorsal, striatum. AAV-mediated, conditional Rit2 knockdown in DAergic neurons impacted baseline DAT surface:intracellular distribution in DAergic terminals from female ventral, but not dorsal, striatum. Further, Rit2 was required for PKC-stimulated DAT internalization in both male and female ventral striatum. FRET and surface pulldown studies in cell lines revealed that PKC activation drives DAT-Rit2 surface dissociation, and that the DAT N-terminus is required for both PKC-mediated DAT-Rit2 dissociation and DAT internalization. Finally, we found that Rit2 and Ack1 independently converge on DAT to facilitate PKC-stimulated DAT endocytosis. Together, our data provide greater insight into mechanisms that mediate PKC-regulated DAT internalization, and reveal unexpected region-specific differences in PKC-stimulated DAT trafficking in bona fide DAergic terminals
A multidisciplinary approach to address climate-resilience, conservation and comfort in traditional architecture: The PROT3CT example
Traditional dwellings despite their environmental credentials, due to age, previous damage, and residents unable to afford even the limited maintenance allowed by restrictive legal framework, may offer poor thermal performance, which is expected to be further exacerbated by changing climate. More than 70% of Turkey’s built heritage stock is composed of traditional dwellings, which makes this stock able to create a major impact nationally on the building-related energy use, carbon emissions and population wellbeing. This research aims to develop an evidence-based multidisciplinary methodology for cost-effective retrofit of the traditional dwellings in Turkey, to improve energy performance, satisfy user expectations of comfort, and protect heritage value
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