5,574 research outputs found
Pool temperature stratification analysis in CIRCE-ICE facility with RELAP5-3D© model and comparison with experimental tests
In the frame of heavy liquid metal (HLM) technology development, CIRCE pool facility at ENEA/Brasimone Research Center was updated by installing ICE (Integral Circulation Experiments) test section which simulates the thermal behavior of a primary system in a HLM cooled pool reactor. The experimental campaign led to the characterization of mixed convection and thermal stratification in a HLM pool in safety relevant conditions and to the distribution of experimental data for the validation of CFD and system codes. For this purpose, several thermocouples were installed into the pool using 4 vertical supports in different circumferential position for a total of 119 thermocouples [1][2]. The aim of this work is to investigate the capability of the system code RELAP5-3D (c) to simulate mixed convection and thermal stratification phenomena in a HLM pool in steady state conditions by comparing code results with experimental data. The pool has been simulated by a 3D component divided into 1728 volumes, 119 of which are centered in the exact position of the thermocouples. Three dimensional model of the pool is completed with a mono-dimensional nodalization of the primary main flow path. The results obtained by code simulations are compared with a steady state condition carried out in the experimental campaign. Results of axial, radial and azimuthal temperature profile into the pool are in agreement with the available experimental data Furthermore the code is able to well simulate operating conditions into the main flow path of the test section
Preferential utilization of endogenous arachidonate by cyclo-oxygenase in incubations of human platelets
AbstractThromboxane B2 (TXB2) and 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) formed from the endogenous and exogenous arachidonate during human platelet incubation, was evaluated by selected ion monitoring (SIM). TXB2 formed from endogenous substrate accounted for about one third of the total, whereas the great part of 12-HETE derived from exogenous arachidonate. These data indicate that under the tested conditions the pool of arachidonate that acts as substrate for cyclo-oxygenase is different from the pool that acts as substrate for lipoxygenase and that the arachidonate released from phospholipids is preferentially utilized by cyclo-oxygenase
Finite element modeling of microstructural changes in hard machining of SAE 8620
Surface and subsurface microstructural characterization after machining operations is a topic of great interest for both academic and industrial research activities. This paper presents a newly developed finite element (FE) model able to describe microstructural evolution and dynamic recrystallization (DRX) during orthogonal hard machining of SAE 8620 steel. In particular, it predicts grain size and hardness variation by implementing a user subroutine involving a hardness-based flow stress and empirical models. The model is validated by comparing its output with the experimental results available in literature at varying the cutting speed, inser0000-0001-6268-6720t geometry and flank wear. The results show a good ability of the customized model to predict the thermo-mechanical and microstructural phenomena taking place during the selected processes
Insomnia symptoms predict emotional dysregulation, impulsivity and suicidality in depressive bipolar II patients with mixed features
Introduction: Insomnia symptoms are very common in Bipolar Disorder. Our aim was to assess the potential association between insomnia, emotion dysregulation and suicidality in subjects with Bipolar Disorder. Methods: Seventy-seven subjects with Bipolar Disorder type II with a depressive episode with mixed features were recruited. Patients were assessed with SCID-DSM-5, the Insomnia Severity Index (ISI), the Difficulties in Emotion Regulation Scale (DERS), the Scale for Suicide Ideation (SSI) while evaluating manic and depressive symptoms. Results: Subjects with insomnia symptoms compared to those without showed higher scores in the DERS scale and subscales, including impulsivity, and in the SSI scale. Insomnia symptoms significantly predicted the severity of depressive symptoms, emotion dysregulation, and suicidality in subjects with bipolar disorder. In particular, insomnia was related to difficulties in some areas of emotion regulation including impulsivity. Emotion dysregulation significantly mediated the association between insomnia and depressive symptoms (Z = 2.9, p = 0.004). Furthermore, emotional impulsivity mediated the association between insomnia symptoms and suicidality (Z = 2.2, p = 0.03). Conclusion: In our study, subjects with bipolar disorder suffering from insomnia experienced a greater severity of depressive symptoms and suicidality compared to subjects without insomnia. Insomnia was associated with emotion dysregulation, impulsivity and suicidality. Further research is necessary to investigate if these latter features may benefit from early insomnia treatment in subjects with bipolar disorder
Media use during adolescence: the recommendations of the Italian Pediatric Society.
BACKGROUND: The use of media device, such as smartphone and tablet, is currently increasing, especially among the youngest. Adolescents spend more and more time with their smartphones consulting social media, mainly Facebook, Instagram and Twitter because. Adolescents often feel the necessity to use a media device as a means to construct a social identity and express themselves. For some children, smartphone ownership starts even sooner as young as 7 yrs, according to internet safety experts. MATERIAL AND METHODS: We analyzed the evidence on media use and its consequences in adolescence. RESULTS: In literature, smartphones and tablets use may negatively influences the psychophysical development of the adolescent, such as learning, sleep and sigh. Moreover, obesity, distraction, addiction, cyberbullism and Hikikomori phenomena are described in adolescents who use media device too frequently. The Italian Pediatric Society provide action-oriented recommendations for families and clinicians to avoid negative outcomes. CONCLUSIONS: Both parents and clinicians should be aware of the widespread phenomenon of media device use among adolescents and try to avoid psychophysical consequences on the youngest
Asymptotically optimal quantum channel reversal for qudit ensembles and multimode Gaussian states
We investigate the problem of optimally reversing the action of an arbitrary
quantum channel C which acts independently on each component of an ensemble of
n identically prepared d-dimensional quantum systems. In the limit of large
ensembles, we construct the optimal reversing channel R* which has to be
applied at the output ensemble state, to retrieve a smaller ensemble of m
systems prepared in the input state, with the highest possible rate m/n. The
solution is found by mapping the problem into the optimal reversal of Gaussian
channels on quantum-classical continuous variable systems, which is here solved
as well. Our general results can be readily applied to improve the
implementation of robust long-distance quantum communication. As an example, we
investigate the optimal reversal rate of phase flip channels acting on a
multi-qubit register.Comment: 17 pages, 3 figure
Inflammatory bowel disease: an increased risk factor for recurrent laryngeal nerve palsy in thyroid surgery
Transient or permanent recurrent laryngeal nerve palsy is a well known complication in thyroid surgery with reported incidences of 5-8%
and 1-3%, respectively 1. Diplegia has an incidence of 0.4% 2. Inflammatory bowel disease (IBD) is an important cause of peripheral neurosensitivity,
particularly autonomic neuropathy, which can lead to transient or permanent laryngeal nerve palsy when neural structures are
involved during surgery. Several mechanisms have been implicated in the physiopathology of these neurological disorders, but the actual
mechanism is still unknown. Herein we report on two patients with IBD presenting with transient bilateral recurrent laryngeal nerve palsy
after total thyroidectomy without any evident mechanical or traumatic manoeuvres on apparently preserved nerves
Sleep/wake rhythm modifications in the Italian population during SARS-CoV2 pandemic: a web-based cross-sectional survey.
Abstract. – OBJECTIVE: The study aims to
investigate in a representative sample of the
Italian population whether the SARS-CoV2 pandemic and the subsequent home isolation had
repercussion on the daily sleep/wake cycling
and habits.
MATERIALS AND METHODS: A web-based
cross-sectional survey consisted of various multiple-choice questions concerning demographic characteristics, sleep habits, and sleep-related problems was broadcast through mainstream social-media. Individuals were randomly allowed to participate from April 29th to May
17th, namely 50 days after the lockdown imposition and the day before its abrogation.
RESULTS: 58.84% of respondents experienced a change in their sleep habits. 71% of
those whose sleep changed showed a delayed
sleep pattern. Overall, a two-fold risk of delayed
sleep pattern without any change in total sleep
time emerged during the investigation period.
Females emerged almost 2 times more likely
to modify their sleep habits than males. Youths
were also more likely to experience modifications than old people, who conversely appeared
protected. A significant improvement in daytime
sleepiness occurred during the home isolation
which additionally correlated with delayed bedtime and less sleep time.
CONCLUSIONS: A high rate of change in
sleep habits, especially among youths and females, occurred in Italian population during the
home isolation to limit the SARS-CoV2 pandemic. Moreover, self-reported daytime sleepiness
decreased in severity
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