An intelligent controller for data acquisition from streamer tube calorimeters

We have built an intelligent controller for acquisition and pre-elaboration of data coming from the read-out electronics of streamer tube calorimeters. Its main features are very short acquisition time and low costs.     

Postprandial hypotension in Alzheimer''s disease

The degree of postprandial hypotension in patients with Alzheimer's disease (AD) is not known. We therefore studied ten AD patients and 23 controls before and after a meal. Seven AD patients but only six controls showed a fall in blood pressure (BP) of 20 mmHg or more. Maximum BP fall in AD patients was observed between 20 and 120 min after food ingestion. This differed from the time course in other groups with primary chronic autonomic failure. Postural hypotension occurred in two controls, but not in AD patients. Abnormalities in cardiac vasomotor regulation, gut peptide liberation or both could be responsible for postprandial hypotension in AD.     

An accurate gate length extraction method for sub-quarter micronMOSFET's

By comparing measured and simulated gate-to-source/drain capacitances, C_gds, an accurate gate length extraction method is proposed for sub-quarter micron MOSFET's applications. We show that by including the 2-D field effect on the fringing capacitance, the polysilicon depletion and the quantum-well effects in the C_gds simulation, the polysilicon gate length, L_poly, can be accurately determined for device lengths down to the 0.1 μm regime. The accuracy of this method approaches that of cross-sectional TEM on the device under test, but without destroying the device. Furthermore, we note that as a result of accurate L_poly extraction, the source/drain lateral diffusion length, L_diff , and effective channel length, L_eff, can also be determined precisely. The accuracy of L_diff is confirmed by examining their consistency with experimentally obtained 2-D source/drain profile     

Laparoscopy in high-risk cardiac patients

Fifteen patients with severe cardiac disease (American Society of Anesthesiologists III or IV) underwent laparoscopy using radial artery and pulmonary artery catheters to determine intraoperative hemodynamic changes. Cardiac output (CO), mean arterial blood pressure (MAP), central venous pressure, heart rate, systemic vascular resistance (SVR) and mixed venous oxygen saturation (SVO2) were recorded before anesthetic induction, after induction, but before peritoneal insufflation, after insufflation and after release of pneumoperitoneum. Peritoneal insufflation led to significant elevations in MAP and SVR and reduction in CO. For seven patients, a decrease in SVO2 after peritoneal insufflation was predictive of significant worsening of hemodynamic parameters, suggesting inadequate cardiac reserve. In all patients, hemodynamic parameters returned toward baseline once pneumoperitoneum was released. There were no perioperative cardiac complications. While it is evident that laparoscopy presents serious hemodynamic stress, it can be performed safely in high-risk patients, using aggressive intraoperative monitoring.     

Optically active vinyl polymers containing fluorescent groups: 5. Fluorescence properties of poly(9-vinyl carbazole) and optically active polymers containing carbazole units

The optically active homopolymers polyl, polyll, and polylll and copolymers of 9-vinyl carbazole with (?)menthyl vinyl ether all exhibit fluorescence related to that of cationically and free radically prepared poly(9-vinyl carbazole). The fluorescence is interpreted for all polymers as arising from three components: monomeric carbazole emission, high energy excimer emission (termed dimer emission for convenience), and a more usual excimer emission arising from conformationally eclipsed carbazole units. Correlations of fluorescence and fluorescence quenching by maleic anhydride, with chiroptical properties and copolymer compositions, suggest that excimer formation is a consequence of rotational freedom within or between isotactic carbazole sequences in the polymer backbones. The isotactic copolymers of (?)menthyl vinyl ether and 9-vinyl carbazole exhibit a relatively strong excimer fluorescence even though mean sequence lengths of carbazole units are comparatively short.     

Electrochemical sensor for ranitidine determination based on carbon paste electrode modified with oxovanadium (IV) salen complex

The preparation and electrochemical characterization of a carbon paste electrode modified with the N,N-ethylene-bis(salicyllideneiminato)oxovanadium (IV) complex ([VO(salen)]) as well as its application for ranitidine determination are described. The electrochemical behavior of the modified electrode for the electroreduction of ranitidine was investigated using cyclic voltammetry, and analytical curves were obtained for ranitidine using linear sweep voltammetry (LSV) under optimized conditions. The best voltammetric response was obtained for an electrode composition of 20% (m/m) [VO(salen)] in the paste, 0.10 mol L^? 1 of KCl solution (pH 5.5 adjusted with HCl) as supporting electrolyte and scan rate of 25 mV s^? 1. A sensitive linear voltammetric response for ranitidine was obtained in the concentration range from 9.9 × 10^? 5 to 1.0 × 10^? 3 mol L^? 1, with a detection limit of 6.6 × 10^? 5 mol L^? 1 using linear sweep voltammetry. These results demonstrated the viability of this modified electrode as a sensor for determination, quality control and routine analysis of ranitidine in pharmaceutical formulations.