A novel topology for a HEMT negative current mirror

A new solution for the implementation of a HEMT negative current source is presented. The topology can be also profitably employed as a current mirror and as an active load in high-gain MMICs voltage amplifiers. A small-signal model of the proposed circuit is developed which allows to find accurate expressions for the required transfer functions (i.e., the output impedance of the current source, and the current gain of the circuit when operated as a current mirror). Design examples using Philips PML ED02AH GaAs PHEMT process are provided. Spice simulations show that a 10- kW output impedance for the current source and a 35dB voltage gain for a differential pair loaded with the proposed current mirror are easily achieved

Enhanced Recovery after Bariatric Surgery: 202 Consecutive Patients in an Italian Bariatric Center

Background: Enhanced Recovery After Surgery (ERAS) pathways have been shown to improve postoperative outcomes. However, its application in bariatric surgery is still limited. The aim of the study was to define the safety of ERAS in bariatric patients with regard to postoperative complications, length of hospital stay (LOS), and readmission rates within 30\ua0days from surgery. Methods: The effectiveness and safety of an ERAS protocol was prospectively investigated in morbidly obese patients who underwent bariatric surgery in a single-institute experience over a 2-year period. Results: Between June 2016 and September 2018, a total of 89 laparoscopic sleeve gastrectomy (SG), 105 Roux-en-Y gastric bypass (RYGB), and 8 one-anastomosis gastric bypass (OAGB) were performed. Twenty patients (9.9%) were revisional cases. Mean (standard deviation, SD) BMI and age at time of surgery were 43.2 (\ub1 6.2)\ua0kg/m2 and 46 (\ub1 11.3)\ua0years, respectively. Median (range) surgical time was 118 (45\u2013255) minutes. Overall postoperative complication rate was 7.4%, with 6 (3.0%) patients developing grade III\u2013IV complications according to the Clavien-Dindo classification. Median (range) LOS was 2 (1\u201350)\ua0days, with mean (SD) LOS of 2.3 (\ub1 3.6)\ua0days. Overall, 36.6% of patients were discharged by first postoperative day and 77.7% by second postoperative day. Readmission rate was 4.5%. No mortality was observed during the study period. Conclusions: According to the results of the present study, ERAS in primary and revisional bariatric surgery is safe and feasible, with short LOS, low morbidity and readmission rates, and no mortality. A significant reduction of mean LOS was progressively noted over the study period

Free and Dissolved Gases in Castrocaro Spa Waters (Italy)

Free and dissolved gases in cold water samples from the Castrocaro spa, Northern Italy, were analyzed for their chemical composition. These gases were interpreted as the result of the binary mixing between a N2- and a CH4-rich component. CO2 is generally a minor constituent. N2/Ar ratios below the air typical value suggest that air saturated water (ASW) is the most likely source of atmospheric-derived components. This atmospheric end-member is predominant in low-salinity waters. Conversely, CH4-enriched gases are mainly associated with brackish to saline waters. The occurrence of minor amounts of light hydrocarbons (C2-C3) indicates a predominant biogenic origin of CH4. The He isotopic composition of the CH4-richest sample (3He/4He = 0.22 Ra) is in the range of values measured for cold seeps and mud volcanoes along the Northern Apennines foothills, and indicates a predominant crustal origin of this gas

Redox regulation of cellular stress response in multiple sclerosis

Multiple sclerosis (MS) is an autoimmune-mediated neurodegenerative disease with characteristic foci of inflammatory demyelination in the brain, spinal cord, and optic nerves. Recent studies have demonstrated not only that axonal damage and neuronal loss are significant pathologic components of MS, but that this neuronal damage is thought to cause the permanent neurologic disability often seen in MS patients. Emerging finding suggests that altered redox homeostasis and increased oxidative stress, primarily implicated in the pathogenesis of MS, are a trigger for activation of a brain stress response. Relevant to maintenance of redox homeostasis, integrated mechanisms controlled by vitagenes operate in brain in preserving neuronal survival during stressful conditions. Vitagenes encode for heat shock proteins (Hsp) Hsp32, Hsp70, the thioredoxin and the sirtuin protein systems. In the present study we assess stress response mechanisms in the CSF, plasma and lymphocytes of control patients compared to MS patients. We found that the levels of vitagenes Hsp72, Hsc70, HO-1, as well as oxidative stress markers carbonyls and hydroxynonenals were significantly higher in the blood and CSF of MS patients than in control patients. In addition, an increased expression of Trx and sirtuin 1, together with a decrease in the expression of TrxR were observed. Our data strongly support a pivotal role for redox homeostasis disruption in the pathogenesis of MS and, consistently with the notion that new therapies that prevent neurodegeneration through nonimmunomodulatory mechanisms can have a tremendous potential to work synergistically with current MS therapies, unravel important targets for new cytoprotective strategies

Entrepreneurship education: the effects of challenge-based learning on the entrepreneurial mindset of university students

The aim of this paper is to investigate the implications of Challenge-Based Learning programs on entrepreneurial skills, and on the mindset and intentions of university students, through a quantitative approach. Resorting to an original database, we analyzed the pre-and post-levels of entrepreneurial skills, mindset and intention of 127 students who attended a Challenge-Based Learning program. Results show a positive and significant effect of Challenge-Based Learning programs on the entrepreneurial mindset and skills—that is, financial literacy, creativity, and planning—of the students

Challenge-based learning as a practice for engineering education to develop students' entrepreneurial mindset

This paper aims to investigate the implications of Challenge Based Learning programs on entrepreneurial skills, mindset and intentions of university students using a quantitative approach. Using an original database, we analyzed pre and post levels of entrepreneurial skills, mindset and intention of 127 students who attended a Challenge Based Learning program. Results show a positive and significant effect of Challenge Based Learning programs on entrepreneurial mindset and skills – such as financial literacy, creativity and planning – of the students. Moreover, results show a positive but non-significative effect on entrepreneurial intention

Extracting the hierarchical organization of complex systems

Extracting understanding from the growing ``sea'' of biological and socio-economic data is one of the most pressing scientific challenges facing us. Here, we introduce and validate an unsupervised method that is able to accurately extract the hierarchical organization of complex biological, social, and technological networks. We define an ensemble of hierarchically nested random graphs, which we use to validate the method. We then apply our method to real-world networks, including the air-transportation network, an electronic circuit, an email exchange network, and metabolic networks. We find that our method enables us to obtain an accurate multi-scale descriptions of a complex system.Comment: Figures in screen resolution. Version with full resolution figures available at http://amaral.chem-eng.northwestern.edu/Publications/Papers/sales-pardo-2007.pd