Are fluid inclusions in gypsum reliable paleoenvironmental indicators? An assessment of the evidence from the Messinian evaporites

The paleosalinity of water from which the gypsum precipitated during the Messinian salinity crisis is a controversial issue. Recent microthermometry studies on primary fluid inclusions in gypsum provided very low salinity values not compatible with precipitation from seawater, and suggested strong mixing between seawater and nonmarine waters enriched in calcium sulfate. We applied a new microthermometric protocol on gypsum crystals from nine Mediterranean sections that were experimentally stretched to measure a larger population of fluid inclusions. The results show salinities ranging from 9 to 238 wt‰ NaCl equivalent, largely falling within the evaporation path of normal seawater. The data from previous studies were obtained mostly from those fluid inclusions capable of nucleating a stable bubble after a weak stretching, which probably correspond to those having a lower salinity acquired through post-depositional crack-and-seal processes. Our data suggest instead that the primary gypsum precipitated from a marine brine, later modified by post-trapping processes during tectonics and exhumation

Ground state of excitons and charged excitons in a quantum well

A variational calculation of the ground state of a neutral exciton and of positively and negatively charged excitons (trions) in single quantum well is presented. We study the dependance of the correlation energy and of the binding energy on the well width and on the hole mass. Our results are are compared with previous theoretical results and with avalaible experimental data.Comment: 8 pages, 5 figures presented to OECS

Cellular Automaton Study of Time-Dynamics of Avalanche Breakdown in IMPATT Diodes

Employing a recently developed efficient cellular automaton technique for solving Boltzmann's transport equation for realistic devices, we present a detailed study of the carrier dynamics in GaAs avalanche p-i-n (IMPATT) diodes. We find that the impact ionization in reverse bias p-i-n diodes with ultrathin (less than 50 nm) intrinsic regions is triggered by Zener tunneling rather than by thermal generation. The impact generation of hot carriers occurs mainly in the low-field junction regions rather than in the high field intrinsic zone. The calculations predict significantly more minority carriers on the n-side than on the p-side

Length and clinical effectiveness of pulmonary rehabilitation in outpatients with chronic airway obstruction

Study objective: To assess the clinical effectiveness of pulmonary rehabilitation (PR) after 10 or 20 consecutive sessions in outpatients with chronic airway obstruction (CAO). Design: Observational prospective cohort trial. Setting: Outpatient clinic of a rehabilitation center. Patients and interventions: Twenty-five outpatients (mean age, 65 +/- 9 years [+/- SD]; FEV1, 64 +/- 12% predicted) admitted to a comprehensive PR program, including exercise training. Measurements and results: The load reached on a cycloergometer (maximal achieved load [W-max]), the maximal and isoload dyspnea and leg fatigue on a Borg scale, 6-min walk distance (6MWD), and the health-related quality of life as assessed using the St. George's Respiratory Questionnaire (SGRQ) [total and components score] have been recorded as outcome measures at baseline, after 10 sessions (T10), and after 20 sessions (T20). The predefined criteria of the clinically significant improvement were as follows: + 15% W-max, + 54 m at 6MWD, - 1 point at isoload dyspnea and leg fatigue, and - 4% at SGRQ scores. There was a mean significant difference between changes at T20 and T10 for 6MWD (- 42.96 m; 95% confidence interval [0], - 57.79 to - 28.12 m; p = 0.001), total SGRQ (4.80; 95% CI, 2.29 to 7.31; p = 0.001), activity SGRQ (3.60; 95% CI, 0.48 to 6.71; p = 0.025), and symptoms SGRQ (5.96; 95% CI, 2.72 to 9.2; p = 0.001). The percentage of patients who improved was different at T20 as compared with T 10 for W-max (68% and 48%, respectively; p = 0.025), 6MWD (76% and 20%, p = 0.001), and total SGRQ (64% and 36%, p = 0.008). Conclusions: A 10-session course of PR provides only limited clinically significant changes of outcome measures when compared with a 20-session course in outpatients with CAO of mild-to-moderate severity

In vitro and in vivo assessment of the potential of escherichia coli phages to treat infections and survive gastric conditions

Enterotoxigenic Escherichia coli (ETEC) and Shigella ssp. infections are associated with high rates of mortality, especially in infants in developing countries. Due to increasing levels of global antibiotic resistance exhibited by many pathogenic organisms, alternative strategies to combat such infections are urgently required. In this study, we evaluated the stability of five coliphages (four Myoviridae and one Siphoviridae phage) over a range of pH conditions and in simulated gastric conditions. The Myoviridae phages were stable across the range of pH 2 to 7, while the Siphoviridae phage, JK16, exhibited higher sensitivity to low pH. A composite mixture of these five phages was tested in vivo in a Galleria mellonella model. The obtained data clearly shows potential in treating E. coli infections prophylactically

Glycaemic control in the perioperative period

The prevalence of type 2 diabetes mellitus and the potential for perioperative dysglycaemia (hyperglycaemia, hypoglycaemia, stress-induced hyperglycaemia, or glucose variability) continue to increase dramatically. The majority of investigations on perioperative glycaemic control focused on critically ill patients and concentrated on goals of therapy, level of intensity of insulin infusion, feeding regimes, concerns over hypoglycaemia, and promulgation of recent guidelines calling for less strict glucose control. Areas of perioperative glycaemic control that deserve further investigation include preoperative identification of patients with undiagnosed type 2 diabetes and other forms of dysglycaemia, determination of appropriate intraoperative glucose goals, and establishment of the impact and natural history of perioperative abnormalities in glucose homeostasis. In the heterogeneous adult perioperative population, it is unlikely that one standard of perioperative glycaemic control is appropriate for all patients. This review presents recent evidence and expert guidance to aid preoperative assessment, intraoperative management, and postoperative care of the dysglycaemic adult patien

Giacitura e origine dei cristalli gessosi di lapis specularis nell\u2019area mediterranea

The Mediterranean basin is characterized by a remarkable variety of widespread gypsum outcrops ranging in age from the Permian to the Holocene. Among them, the Miocene deposits contain large gypsum crystals filling fractures and ancient karst caves that were exploited by the Romans to produce thin transparent cleavage plates to be used as substitute of glass in window panels (lapis specularis). For their size (at least some decimeters across) and perfect transparency, the most sought crystals were those from Spain, which is also the area with the richest lapis specularis deposits. In Italy traces of mining activity have been discovered only recently, while in Cyprus and Turkey, the quarries described by the Roman sources are still unknown. The increasing number of excavation sites continuously discovered in the Vena del Gesso of the Northern Apennines suggests that important discoveries could be made in Sicily, Cyprus and Turkey through specific studies. As indicated by our geological analysis, lapis specularis crystals could also be present in Albania, Algeria, Egypt, Jordan, Greece, Israel, Romania and Tunisia. These locations could represent potential sites of excavation of Roman not mentioned in ancient sources

Interdisciplinary rehabilitation in morbidly obese subjects: an observational pilot study.

BACKGROUND AND AIM: To assess the clinical effectiveness of a interdisciplinary rehabilitation programme (CR), in a population of morbidly obese subjects we have undertaken a observational study. METHODS: The study included fifty-nine adult subjects (18 M, 60+/-10 years, BMI 47+/-8) with sleep-disturbance related symptoms and disabilities. Assessment and correction of sleep disordered breathing (SDB) abnormalities, improvement of exercise tolerance, body weight and associated psychological features were the aims of this CR, which has been carried out over a 1 month period.Lung functions, apnea/hypopnea index (AHI), 6-minute walking distance (6MWD), body weight (BW), quality of life by means of Sat-P questionnaire and serum metabolic data has been recorded at baseline (TO), at the end (Ti) and 6 months after (T2) the CR. RESULTS: The percentage of patients with AHI > 10 declined from 65% (at TO) to 20% (at both T1 and T2). 6MWD and BW significantly improved (p < 0.005) at T1 and still maintained at T2; a significant relationship (r = 0.379, p < 0.01) has been found between changes of BW and 6MWD recorded in between TO and T2. Sat-P item scores dealing with sleep efficiency, problem solving, and social interactions improved (p < 0.01) at T1 and still maintained at T2. CONCLUSIONS: This hospital-based CR provides indication for effectiveness in advanced morbidly obese subjects and warrants further controlled trials to confirm the results