604 research outputs found

    Cardiovascular abnormalities and impaired exercise performance in adolescents with congenital adrenal hyperplasia

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    Context: Patients with classic Congenital Adrenal Hyperplasia (CAH) are treated with lifelong glucocorticoids (GCS). Cardiovascular (CV) and metabolic effects of such therapy in adolescents have never been quantified. Objective: To investigate left ventricular (LV) morphology, function and exercise performance in adolescents with CAH. Design and Setting: cross-sectional and controlled study conducted at a tertiary referral centre. Patients: Twenty patients with classic CAH (10 females) aged 13.6±2.5 years and 20 healthy controls comparable for sex and pubertal status were enrolled in the study and compared to a group of 18 patients without CAH receiving a similar dose of GCS for Juvenile Idiopathic Arthritis (JIA). Main Outcomes Measures: Echocardiographic assessment and symptom-limited exercise testing were performed. Anthropometric, hormonal and biochemical parameters were also measured. Results: Compared to healthy controls, patients with CAH exhibited an increased BMI (p<0.001), waist-to-height ratio (p<0.001), percentage of body fat (p<0.001) as well as higher insulin concentrations and HOMA index even after adjustment for BMI (p=0.03 and p=0.05, respectively). Moreover, CAH patients exhibited an impaired exercise capacity as shown by reduced peak workload (99±27 vs 126±27 W, p<0.01) and higher systolic blood pressure response at peak (156±18 vs 132±11 mmHg, p<0.01; Δ=45±24 vs 22±10 mmHg, p=0.05) with respect to healthy controls. CAH males displayed mild LV diastolic dysfunction as documented by significant prolongation of both isovolumic relaxation time (IRT) (118±18 vs 98±11ms, p<0.05) and mitral deceleration time (MDT) (138±25 vs 111±15 ms, p<0.01). No significant differences in CV function were found between CAH and JIA patients. Conclusion: Adolescents with CAH exhibit impaired exercise performance and enhanced systolic blood pressure response during exercise. In our population, such abnormalities appear related to GCS therapy rather than CAH per se. CAH males, but no females, present mild LV diastolic dysfunction that correlates with testosterone concentrations suggesting a sex hormone related difference

    Heterogeneous design and mechanical analysis of HELIAS 5-B helium-cooled pebble bed breeding blanket concept

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    One of the most challenging objectives of the European research concerning nuclear fusion technology, promoted by the EUROfusion consortium, is to bring stellarator-type nuclear fusion devices to maturity. To this purpose, studies on a large HELIcal-axis advanced stellarator (HELIAS), extrapolated from Wendelstein 7-X and based on a 5-fold symmetry (HELIAS 5-B), are currently ongoing. The HELIAS 5-B stellarator reactor will be endowed with a breeding blanket (BB) system to allow for the self-sustainability of the nuclear fusion reaction and make it suitable for electricity generation. In this paper, we present the first ever heterogeneous mechanical design and the preliminary structural assessment of a bean-shaped ring of a HELIAS 5-B BB sector. The proposed mechanical design, which is based on the helium-cooled pebble bed (HCPB) BB concept and developed according to the “sandwich” architecture, foresees an actively cooled segment box connected to a back-supporting structure equipped with manifolds. The internal region (breeding zone) is reinforced by actively cooled steel plates. The proposed heterogeneous design was checked against nominal loads and an in-box loss of coolant accidental scenario, which is a typical design driver for BBs. The assessment has been performed according to the RCC-MRx structural design code. Our results are herewith presented and critically discussed, focusing on the potential follow-up of the HELIAS 5-B HCPB BB design

    Electromagnetic and electromechanical applications of graphene-based materials

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    This volume contains the extended abstracts of the contributions presented at the workshop Nanoscale Excitations in Emergent Materials (NEEM 2015) held in Rome from 12 to 14 October 2015, an event organized and supported in the framework of the Bilateral Cooperation Agreement between Italy and India within the project of major relevance "Investigating local structure and magnetism of cobalt nano-structures", funded by the Italian Ministry of Foreign Affairs and the Department of Science and Technology in India

    The exploitation of limpets in a Mediterranean Marine Protected Area: assessing the effectiveness of protection in the intertidal zone

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    Limpets are intertidal keystone grazers and their overexploitation could have significant consequences for intertidal communities. Limpets are harvested around the Sinis Peninsula (Sardinia, Italy) but harvesting is prohibited within the “Penisola del Sinis - Isola di Mal di Ventre” Marine Protected Area (MPA). This work assesses the effects of human harvesting on the population dynamics of three common Mediterranean species of Patella, namely, P. rustica, P. caerulea and P. ulyssiponensis, testing the effectiveness of the MPA and the role of site accessibility in limiting the intensity of such harvesting pressure. In the period between June 2015 and August 2016, limpet abundance and size were recorded on a monthly basis by means of photographic frames within linear transects at ten sites spread out along the coastline of the Sinis Peninsula to assess growth and temporal patterns. Limpets older than two years are extremely rare in the study area. Limpets are more abundant within the MPA in comparison with non-protected areas and within less accessible sites in comparison with areas where the intertidal zone is easily accessible from land. Despite this, overall human-induced mortality in the area is high, indeed the pool of limpets observed with a mean density of 104.3 ± 9.7 limpets/m2 during the first survey was reduced by 99.2%in less than one year. This work demonstrates that human harvesting strongly affects the population dynamics of Patella species in the area and that within the MPA this stressor is not efficiently reduced

    Battery- and Petrol-Powered Chainsaws: An Investigation of Productivity in Conifer Thinning

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    In recent years, battery technology has been greatly improved and some types of battery chainsaws are currently comparable with light-type petrol machines, suggesting their possible introduction into forest operations. In this context, the aim of this study was to test and compare the performance, in a Douglas-fir thinning, of two chainsaws similar in terms of weight and power, the Stihl MS 220 CB battery-powered saw and the Stihl MS 201 CM petrol-powered saw, measuring the working times and calculating the productivities. The results showed that, within a working day (about 6 h gross time), an average of 15 trees of 0.56 m3 was felled in each area. No statistically significant differences between the two chainsaws were found in terms of gross and net productivity; and the same result was obtained when focusing the analysis only on operations conducted using the chainsaws. Moreover, the average battery charge duration was 1.04 h, while the full tank duration for the petrol model was 1.12 h. In conclusion, our study demonstrates that, on the basis of their performance, battery chainsaws can be introduced into thinning operations, but a solution is needed to manage batteries in the forest, since the actual need is for 7–8 charges per workday

    Effect of intensive treatment on diabetic nephropathy in patients with type I diabetes

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    Effect of intensive treatment on diabetic nephropathy in patients with type I diabetes. We evaluated the long-term effect of an intensive treatment of diabetic nephropathy (anti-hypertensive drugs, low protein diet, multiple insulin injections to achieve a good metabolic control) on glomerular filtration rate (GFR) and albumin excretion rate (AER). Fourteen type I diabetic patients (mean age 45 ± 9.5 years, mean duration of diabetes 23.5 ± 7.3 years, 8 males/6 females) with glomerular filtration rate <70 ml/min-1/1.73 m2 and albumin excretion rate >30 µg/min were treated intensively for 36 months. This intensive treatment consisted of multiple insulin injections, antihypertensive therapy with ACE inhibitors and a low-protein diet (0.8 g/kg body wt/day.) Renal function was evaluated as GFR and AER. HbA1C mean value decreased significantly from 8.7 ± 0.8% to 6.5 ± 0.5% (P < 0.0002). GFR rose from 58 ± 12 ml/min-1/l.73 m2 to 84 µ 11 ml/min-1/l.73 m2 (P < 0.0008). AER decreased from 208 µg/min (range: 73 to 500) to 63.8 µg/min (range 15 to 180; P < 0.05). Systolic and diastolic blood pressure decreased respectively from 144 ± 26 mm Hg to 120 ± 15 mm Hg and from 89 ± 9 mm Hg to 75 ± 8 mm Hg (P < 0.01). We obtained a rise of GFR and a reduction of proteinuria after three years of this treatment. We suggest that this intensive treatment in all patients with early stage diabetic nephropathy may be effective in slowing the progression to renal failure

    Economías de escala y externalización de labores agrícolas en la región pampeana (Argentina)

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    Lombardo, Patricia Beatriz. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Marra, Rita María Andrea. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.143-153En las últimas décadas en la Argentina, y especialmente en la región pampeana, se ha producido una significativa desaparición de explotaciones agropecuarias y disminución en la cantidad de personas trabajadoras permanentes. Al mismo tiempo, se ha registrado un incremento en la externalización de las labores agrícolas. En dicho contexto, el ente contratista de servicios de maquinaria agrícola se ha ido configurando como una pieza clave para el aumento de la eficiencia productiva, debido a su capacidad para responder en forma ágil y flexible a los cambios técnicos y de organización laboral. Quienes demandan estos servicios conforman un universo heterogéneo tanto en escala de producción como de composición y requerimientos tecnológicos, lo cual incide en su forma de vinculación con los entes contratistas. Entre estos grupos demandantes, ocupan un lugar significativo los pooles de siembra - emprendimientos basados en la generación de economías de escala - que operan grandes superficies de tierra y que prefieren alquilar el servicio de máquinas. Este trabajo tiene como objetivo general analizar las modalidades de vinculación entre estos emprendimientos y contratistas de servicios de maquinaria. Para la consecución de este objetivo, se utilizó un abordaje de tipo cualitativo y la recolección de información se llevó a cabo mediante entrevistas semiestructuradas

    Comparing the Productivity of the Latest Models of Li-Ion Battery and Petrol Chainsaws in a Conifer Clear-Cut Site

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    The recent technological development of batteries has allowed the production of powerful tools that are also used in forestry operations. For this reason, this study aimed to compare the performance of two latest chainsaw models in a conifer clear-cut. The examined chainsaws, the battery-powered Stihl MSA 300 and the petrol-powered MS 261 C-M, have comparable power and weight. The overall working times were recorded and then gross, net and felling/processing productivities were quantified. Our findings reported that in a working day (7.4 h gross time), each chainsaw felled and processed an average of 20 trees of 0.64 m3 with an average diameter at breast height of 28 cm. Considering the net productivity, no statistically significant differences were recorded between the two chainsaws. Investigating the productivities on operations conducted using the chainsaws, the battery chainsaw showed a lower average tree-processing productivity than that recorded for the petrol chainsaw. On average, the battery duration was 0.88 h, while the petrol tank duration was 0.97 h. Our study shows that battery chainsaws have great potential in forestry operations; however, considering the actual need for 8 charges per standard workday, optimizing battery management is an important objective for future work

    Preoperative anxiety during COVID-19 pandemic: A single-center observational study and comparison with a historical cohort

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    Background: Preoperative anxiety is a common sensation experienced by patients undergoing surgical interventions. It can influence intraoperative and postoperative management through the activation of the neuroendocrine system, leading to tachycardia, hypertension, pulmonary complications, higher consumption of anesthetic drugs, and increased postoperative pain. Our aim was to investigate the level of preoperative anxiety during the COVID-19 pandemic; we also compared it to the preoperative anxiety of a historical cohort before the outbreak. Methods: This is a single-center observational study. We enrolled 314 patients during the pandemic from May 2021 to November 2021, and our historical cohort consisted of 122 patients enrolled from July 2015 to May 2016 in the university hospital "Federico II" of Naples. The Amsterdam Preoperative Anxiety and Information Scale (APAIS) and the State-Trait Anxiety Inventory (STAI) were used to evaluate preoperative anxiety. In particular, APAIS measures preoperative anxiety and the need for information, and STAI assesses state and trait anxiety through STAI-Y1 and STAI-Y2, respectively. We analyzed APAIS and STAI scores in our population stratified on the basis of age, gender, marital status, previous surgical experiences, and type of surgery, and we compared them to our historical cohort. Statistical analysis was performed through a t-test and ANOVA for parametric data, and the Mann-Whitney and Kruskal-Wallis tests for non-parametric data. Linear regression was used to investigate the correlation between demographic data and the scores of STAI and APAIS in both groups. Results: Our results showed that state and preoperative anxiety remained stable, whereas trait anxiety increased in all the subgroups analyzed. Discussion: Even if state anxiety is considered a variable characteristic of the emotional sphere and trait anxiety a stable element, our findings suggested that COVID-19 deeply influenced trait anxiety, thus altering the patients' psychological foundations
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