Investigation of degradation mechanisms in low-voltage p-channel power MOSFETs under High Temperature Gate Bias stress

In this work we investigate the degradation mechanisms occurring in a p-channel trench-gate power MOSFET under High Temperature Gate Bias (HTGB) stress. The impact of negative bias temperature stress is analysed by evaluating relevant figures of merit for the considered device: threshold voltage, transconductance and on-resistance. Temperatures and gate voltages as large as 175 \ub0C and 1224 V, respectively, are adopted to accelerate the degradation in the device. Moreover, in order to investigate the origin of degradation mechanisms we analyse the interface states generation and the charge trapping processes, the impact of a switching gate voltage during the stress phase and the recovery phase after HTGB stress

Mursia, Pantelleria (TP)

Le ricerche condotte durante gli anni 2014-2015 nell'abitato dell'et\ue0 del Bronzo di Mursia (Pantelleria), affidate alla sezione di Archeologia del Dipartimento di Storia Culture Civilt\ue0 dell'Universit\ue0 di Bologna hanno interessato i settori a monte della strada perimetrale fino al grande muro difensivo dell'et\ue0 del Bronzo. Nelle campagne 2014 e 2015 e proseguita l'indagine del Settore B incentrata sull'area della capanna B13, una struttura a pianta ovale allungata orientata in senso NW-SE (assi di 11 x 4,3 m). Identificata in precedenza dalle estremit\ue0 absidate settentrionale e meridionale e da brevi segmenti discontinui sul lato orientale e occidentale, la capanna era stata attribuita al modello delle capanne della prima fase insediativa del settore. Lo scavo ha messo in evidenza diversi episodi di ristrutturazione tra cui quello pi\uf9 significativo e indicato dalla separazione in due distinti ambienti allineati in senso N-S e accostati lungo il lato corto. A marcare questa distinzione gia concepita in un momento piuttosto antico e una struttura muraria in E-W, la cui funzione di divisorio persiste con una serie di rifacimenti fino alle fasi recenti. Nel Settore C, oltre le strutture gi\ue0 individuate negli scavi del 1970 di Carlo Tozzi dell'Universit\ue0 di Pisa (C1, C2, C3), sono state messe in luce altre tre strutture (C4, C5, C6) caratterizzate da una pianta ovale allungata. Lo scavo si e concentrato nella capanna C4, orientata Nord-Ovest Sud-Est, con una dimensione di 7 x 3 m. Durante il 2014 e iniziata l'esplorazione del Settore E, con un saggio a ridosso dei muri di terrazzamento moderni che delimitano il crollo del grande muro perimetrale. Infine le ricerche nel Settore F hanno completato l\u2019indagine di un ambiente quadrangolare (F1), all\u2019interno del quale era stato rinvenuto nel 2013 un grande numero di forme di fusione e materiale archeologico in giacitura primaria

Heteroaromatic Chromophores: Structure, Electric Properties, Condensed Phase and Aggregation Effects: a Combined Experimental and Theoretical Study

We present a combined computational and experimental study on structural and electric properties of recently synthesized heteroaromatic dyes and their simple aggregates. Ab initio and density functional theory calculations are carried out to investigate ground state and excited state properties along with their modulation induced by the solvent described with the implicit solvent polarizable continuum model. The results are compared with experimental data concerning spectroscopic studies. Electronic and vibrational contributions to the first hyperpolarizability and condensed phase effects on these properties are also evaluated for single or selected dimeric chromophore structures. Intermolecular interactions are evaluated both at correlated ab initio level and with simplified atomistic models employing molecular mechanics force fields parametrized, as regard electrostatic interactions, on the basis of ab initio computed partial atomic charges. Specific chromophore orientations are considered and the results of the two procedures are compared

Rationale for cardiopulmonary exercise test in the assessment of surgical risk.

Although in the past years a reduced mortality in peri-operative care has been observed, cardiovascular mortality and morbidity still is a major burden in patients undergoing noncardiac surgery and its evaluation is still a difficult task. An accurate risk stratification can improve quality of peri-operative care and may improve survival, while reducing healthcare costs. In clinical practice, we make our assessment of a patient's cardiac status based on history, examination and investigations, together with risks related to the surgical procedure, to generate an 'individualized cardiac risk assessment'. At the present, risk stratification with clinical risk score and cardiac testing have been shown to be suboptimal in identifying high-risk patients. Surgery, like exercise, increases oxygen consumption. Indeed, one of the key elements in determining risk assessment is exercise intolerance, but future research in this field is needed to clarify this statement. Cardiopulmonary exercise testing (CPET) provides a global assessment of functional capacity involving and integrating the physiological measurement during incremental exercise. The pattern of CPET's variables identifies the abnormal exercise capacity, often providing an objective evaluation of cause and, moreover, predicting outcomes in both apparently healthy and chronic disease populations. An anaerobic threshold VO2 above 11\u200aml/kg per min seems to identify individuals with a very low surgical risk even if undergoing major surgery. This review is focused on tools of risk assessment in patients undergoing noncardiac surgery and on the physiological basis for CPET in detecting patients 'at risk'

Lypolytic enzymes separation and purification through functionalized synthetic polymers.

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Prognostic Value of Indeterminable Anaerobic Threshold in Heart Failure.

BACKGROUND: In patients with heart failure (HF), during maximal cardiopulmonary exercise test, anaerobic threshold (AT) is not always identified. We evaluated whether this finding has a prognostic meaning. METHODS AND RESULTS: We recruited and prospectively followed up, in 14 dedicated HF units, 3058 patients with systolic (left ventricular ejection fraction <40%) HF in stable clinical conditions, New York Heart Association class I to III, who underwent clinical, laboratory, echocardiographic, and cardiopulmonary exercise test investigations at study enrollment. We excluded 921 patients who did not perform a maximal exercise, based on lack of achievement of anaerobic metabolism (peak respiratory quotient 641.05). Primary study end point was a composite of cardiovascular death and urgent cardiac transplant, and secondary end point was all-cause death. Median follow-up was 3.01 (1.39-4.98) years. AT was identified in 1935 out of 2137 patients (90.54%). At multivariable logistic analysis, failure in detecting AT resulted significantly in reduced peak oxygen uptake and higher metabolic exercise and cardiac and kidney index score value, a powerful prognostic composite HF index (P<0.001). At multivariable analysis, the following variables were significantly associated with primary study end point: peak oxygen uptake (% pred; P<0.001; hazard ratio [HR]=0.977; confidence interval [CI]=0.97-0.98), ventilatory efficiency slope (P=0.01; HR=1.02; CI=1.01-1.03), hemoglobin (P<0.05; HR=0.931; CI=0.87-1.00), left ventricular ejection fraction (P<0.001; HR=0.948; CI=0.94-0.96), renal function (modification of diet in renal disease; P<0.001; HR=0.990; CI=0.98-0.99), sodium (P<0.05; HR=0.967; CI=0.94-0.99), and AT nonidentification (P<0.05; HR=1.41; CI=1.06-1.89). Nonidentification of AT remained associated to prognosis also when compared with metabolic exercise and cardiac and kidney index score (P<0.01; HR=1.459; CI=1.09-1.10). Similar results were obtained for the secondary study end point. CONCLUSIONS: The inability to identify AT most often occurs in patients with severe HF, and it has an independent prognostic role in HF

Severe heart failure prognosis evaluation for transplant selection in the era of beta-blockers: role of peak oxygen consumption.

Severe heart failure prognosis evaluation for transplant selection in the era of beta-blockers: role of peak oxygen consumption

Metabolic exercise test data combined with cardiac and kidney indexes, the MECKI score: A multiparametric approach to heart failure prognosis.

OBJECTIVES: We built and validated a new heart failure (HF) prognostic model which integrates cardiopulmonary exercise test (CPET) parameters with easy-to-obtain clinical, laboratory, and echocardiographic variables. BACKGROUND: HF prognostication is a challenging medical judgment, constrained by a magnitude of uncertainty. METHODS: Our risk model was derived from a cohort of 2716 systolic HF patients followed in 13 Italian centers. Median follow up was 1041days (range 4-5185). Cox proportional hazard regression analysis with stepwise selection of variables was used, followed by cross-validation procedure. The study end-point was a composite of cardiovascular death and urgent heart transplant. RESULTS: Six variables (hemoglobin, Na(+), kidney function by means of MDRD, left ventricle ejection fraction [echocardiography], peak oxygen consumption [% pred] and VE/VCO(2) slope) out of the several evaluated resulted independently related to prognosis. A score was built from Metabolic Exercise Cardiac Kidney Indexes, the MECKI score, which identified the risk of study end-point with AUC values of 0.804 (0.754-0.852) at 1year, 0.789 (0.750-0.828) at 2years, 0.762 (0.726-0.799) at 3years and 0.760 (0.724-0.796) at 4years. CONCLUSIONS: This is the first large-scale multicenter study where a prognostic score, the MECKI score, has been built for systolic HF patients considering CPET data combined with clinical, laboratory and echocardiographic measurements. In the present population, the MECKI score has been successfully validated, performing very high AUC