980 research outputs found
Characterization of metabolically healthy obese people and metabolically unhealthy normal-weight people in a general population cohort of the ABCD Study
There is actually no consensus about the possibility that in some instances, obesity may be a benign metabolically healthy (MH) condition as opposed to a normal-weight but metabolically unhealthy (MUH) state. The aim of this study was to characterize MH condition and to investigate possible associations with metabolic and cardiovascular complications. One thousand nineteen people (range of age 18-90 years) of the cohort of the ABCD-2 study were investigated. Participants were classified as normal weight (BMI < 24.9 kg/m2) or overweight-obese (BMI \ue2\u89\ua525 kg/m2); they were also classified as MH in the presence of 0-1 among the following conditions: (a) prediabetes/type 2 diabetes, (b) hypertension, (c) hypertriglyceridemia or low HDL cholesterolemia, and (d) hypercholesterolemia. MUH condition was diagnosed if \ue2\u89\ua52 of the conditions listed were found. The prevalence of overweight/obese people was 71.1%, of whom 27.4% were found to be MH. In addition, 36.7% of the normal-weight participants were MUH. HOMA-IR, high sensitivity C-reactive protein, and the carotid intima-media thickness were significantly different in the 4 subgroups (P < 0.001), with higher values observed in the MUH normal-weight and obese groups. In conclusion, this study highlights the importance of identifying a MH condition in normal-weight and in obese people in order to offer better treatment
Regression analysis to design a solar thermal collector for occasional use
Optimal design of a solar thermal system is necessary to minimize payback time and to diffuse renewable energy use for Domestic Hot Water production in residential areas. More accurate design is crucial in the case of seasonal or occasional use of the system; indeed, the standard criteria generally applied to a design system for continuous use, can lead to considerable over-sizing. To speed up the design phase and to help the planner in the identification of the best solution without any complex evaluation or long computational time, it would be interesting to have available a simpler method than the standard procedures, but one that is reliable and accurate for the evaluation of the best configuration, taking into account occasional use, seasonal and monthly domestic hot water demand, orientation and primary flow rate. To this end, the authors investigated a methodology for the identification of some empirical correlations based on the analysis of data coming from a parametric simulation; in this way the identified correlations can indicate, with high reliability, the optimal design knowing only well-known parameters. In detail, the data output was extracted and processed to evaluate the best design configurations under any operative conditions. Determination of the best configuration identifies the operative parameters that maximize the Solar Fraction of the plant and minimize the auxiliary energy. To highlight the reliability of this methodology, in this work, the authors describe a case study of the Sicilian region proposing a set of simple, reliable correlations that allow the determination of the best tilt angle for monthly or seasonal use. Following the same steps the procedure can be replicate in any context and in any conditions
Reoperation for persistent or recurrent secondary hyperparathyroidism
Background: Secondary hyperparathyroidism is a common acquired disorder seen in chronic renal failure. Its pathophysiology is mainly due to hyperphosphatemia and vitamin D deficiency and resistance. When medical treatment fails, subtotal and total parathyroidectomy with autotransplantation are the standard procedures, although both are associated with high recurrence rates.Methods and Results: 4 patients experienced
persistence and 9 relapse. The first 4 were subjected to reoperation after 6 months for the persistence of symptoms due to the finding of a supernumerary adenomatous gland while the remaining patients at the reoperation showed in 5 cases 2 more glands in over thymic position, and 4 an hyperplasia of the residual glandular tissue. A classic cervicotomy was sufficient to remove the residual parathyroid in patients with persistent hyperparathyroidism. For cases of recurrent hyperparathyroidism it was enough a medial approach and sometimes lateral for the complete excision of the hyperplastic tissue. The advent of the intraoperative technique of parathyroid hormone dosage allowed a better performance of the surgical technique for the last 3 patients undergoing reoperation. After reoperation all patients had immediate regression of clinical symptoms with normalization of serum calcium and PTH levels. Conclusions: On the basis of these considerations, diagnostic imaging has a not negligible role because during the first intervention helps to have an idea of the possible location of the glands and thus to avoid the risk of recurrence and relapse due to ectopic or supernumerary tissue
A validated energy model of a solar dish-Stirling system considering the cleanliness of mirrors
Solar systems based on the coupling of parabolic concentrating collectors and thermal engines (i.e. dish-Stirling systems) are among the most efficient generators of solar power currently available. This study focuses on the modelling of functioning data from a 32 kWe dish-Stirling solar plant installed at a facility test site on the University of Palermo campus, in Southern Italy. The proposed model, based on real monitored data, the energy balance of the collector and the partial load efficiency of the Stirling engine, can be used easily to simulate the annual energy production of such systems, making use of the solar radiation database, with the aim of encouraging a greater commercialisation of this technology. Introducing further simplifying assumptions based on our experimental data, the model can be linearised providing a new analytical expression of the parameters that characterise the widely used Stine empirical model. The model was calibrated against data corresponding to the collector with clean mirrors and used to predict the net electric production of the dish-Stirling accurately. A numerical method for assessing the daily level of mirror soiling without the use of direct reflectivity measures was also defined. The proposed methodology was used to evaluate the history of mirror soiling for the observation period, which shows a strong correlation with the recorded sequence of rains and dust depositions. The results of this study emphasise how desert dust transport events, frequent occurrences in parts of the Mediterranean, can have a dramatic impact on the electric power generation of dish-Stirling plants
Electron interference and entanglement in coupled 1D systems with noise
We estimate the role of noise in the formation of entanglement and in the
appearance of single- and two-electron interference in systems of coupled
one-dimensional channels semiconductors. Two cases are considered: a
single-particle interferometer and a two-particle interferometer exploiting
Coulomb interaction. In both of them, environmental noise yields a
randomization of the carrier phases. Our results assess how that the
complementarity relation linking single-particle behavior to nonlocal
quantities, such as entanglement and environment-induced decoherence, acts in
electron interferometry. We show that, in a experimental implementation of the
setups examined, one- and two-electron detection probability at the output
drains can be used to evaluate the decoherence phenomena and the degree of
entanglement.Comment: 12 pages, 6 figures. v2: added some references and corrected tex
Obstetrics and Gynecology Emergency Department Activity during Lockdown in a Teaching Hospital, Hub Center, for COVID-19
Background. The lockdown related to the SARS-CoV-2 pandemic has imposed profound changes in the interaction of the population with hospitals and emergency departments. The main aim of this research was to evaluate the impact of lockdown on the activity of obstetrics and gynecology emergency department (OGED) in a teaching hospital, hub center, for COVID-19. Methods. The study considers all visits to the OGED with their different triage color codes that represent the clinical severity of each case (from the most severe to the least one: red, yellow, green, white). Data were selected through the "PSNet"triage program and collected anonymously. We analyzed frequency distributions of the variables separately for each woman and calculated mean and standard deviations for continuous variables. We then analyzed the association between factors and outcomes for categorical variables (expressed as a number and percentage of the total) using the chi-square test (χ2). The level of significance was established with p<0.05. Statistical analysis was performed using SPSS Statistics V20.0. Given the fact that the study has a retrospective observational nature and it is based on an anonymous routine database, approval by the Local Ethics Committee was not necessary. Results. The relative decrease of patients presenting to OGED in 2020 was -50.96%. The percentage of nonpregnant women was significantly lower in 2020 compared to 2019 (p≤0.0001; Δ = -79.46%). Regarding the obstetric group, we saw an important decrease of visits in 2020 compared to 2019 (p<0.0001; Δ = -40%). The prevalence of yellow codes was significantly higher in 2020 (Δ = +29.72%), while that of white (Δ = -61.58%) and green (Δ = -52.22%) codes was significantly lower (p≤0.0001). Comparing the diagnoses at discharge, we could highlight significant reductions in 2020 for more than one diagnosis: bleeding (p≤0.0001; Δ = -70.42%), pain (p≤0.0001; Δ = -81.22%), urinary diseases (p=0.004; Δ = -75.64%), and gastrointestinal diseases (p≤0.0001; Δ = -87.50%). Conclusions. An evident change emerged in relation to the dynamics between the local obstetrical and gynecological population, and OGED resources. The COVID-19 lockdown greatly reduced the rate of admission to OGED without time-related obstetric and gynecological complications. The reduction of admissions suggests a more appropriate use of the ED by patients that may inspire future policies for the implementation of emergency services
Superbroadcasting of continuous variables mixed states
We consider the problem of broadcasting quantum information encoded in the
average value of the field from N to M>N copies of mixed states of radiation
modes. We derive the broadcasting map that preserves the complex amplitude,
while optimally reducing the noise in conjugate quadratures. We find that from
two input copies broadcasting is feasible, with the possibility of simultaneous
purification (superbroadcasting). We prove similar results for purification
(M<=N) and for phase-conjugate broadcasting.Comment: 11 pages, 1 figure, revtex4 style, revised versio
Electrospun PHEA-PLA/PCL Scaffold for Vascular Regeneration: A Preliminary in\ua0Vivo Evaluation
Background. There is increasing interest in the development of vessel substitutes, and many studies are currently focusing on the development of biodegradable scaffolds capable of fostering vascular regeneration. We tested a new biocompatible and biodegradable material with mechanical properties similar to those of blood vessels.
Methods. The material used comprises a mixture of a,b-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) and polylactic acid (PLA), combined with polycaprolactone (PCL) by means of electrospinning technique. Low-molecular-weight heparin was also linked to the copolymer. A tubular PHEA-PLA/PCL sample was used to create an arteriovenous fistula in a pig model with the use of the external iliac vessels. The flow was assessed by means of Doppler ultrasound examination weekly, and 1 month after the implantation we removed the scaffold for histopathologic evaluation.
Results. The implants showed a perfect leak-proof seal and adequate elastic tension to blood pressure. About w3 weeks after the implantation, Doppler examination revealed thrombosis of the graft, so we proceeded to its removal. Histologic examination showed chronic inflammation, with the presence of foreign body cells and marked neovascularization. The material had been largely absorbed, leaving some isolated spot residues.
Conclusions. The biocompatibility of PHEA-PLA/PCL and its physical properties make it suitable for the replacement of vessels. In the future, the possibility of functionalizing the material with a variety of molecules, to modulate the inflammatory and coagulative responses, will allow obtaining devices suitable for the replacement of native vessels
Renal allograft compartment syndrome: is it possible to prevent?
Renal allograft compartment syndrome (RACS) is a complication characterized by increased pressure over 15 to 20 mm Hg of the iliac fossa site of transplanted kidney that can lead to a reduction of the blood supply to the graft, resulting in organ ischemia. This study aims to evaluate, through a review of the literature, the incidence, detection, treatment, and possible prevention of RACS. The incidence of this complication, which appears generally in the immediate post-transplantation period, is currently approximately 1% to 2% and is underestimated because of poor nosography for the presence of symptoms common to other post-transplantation complications. Doppler ultrasound is indispensable to evaluate the graft function in the immediate postoperative period and in the following days. The onset of RACS involves a surgical decompression of the graft and the subsequent closure of the abdominal wall with tension-free technique. Several authors agree that only the immediate surgical decompression following an early diagnosis can ensure a recovery of the graft. Early detection of the RACS is the key to preventing the loss of the graft. It is desirable to prevent this syndrome by reducing the discrepancy in weight between donor and recipient by 17%. However the shortage of organs makes such a selection not easy; therefore, in cases at risk for RACS, a close instrumental and clinical monitoring of the patient during post-transplantation recovery is recommended, so a prompt surgical decompression can be performed if RACS is suspected
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