Low Voltage Trench-Gate MOSFET Power Losses Optimization in Synchronous Buck Converter Applications

The paper deals with the optimal selection of low side and high side switches, in a synchronous buck converter, based on energy losses as well as dynamic switching characteristics as focused parameters. The MOSFET in trench-gate technology investigated is based on a strip-geometry layout which allows an excellent trade-off between the on-resistance and the gate charge. In the proposed paper main technology issues are shortly recalled and the advantages deriving from the improved device are focused. Furthermore, the switching behavior in actual synchronous buck converter circuit applied as a power supply for auxiliary electronic automotive accessories has been evaluated. Last generation trench-gate MOSFET at different current ratings are tested in order to give evidence to the effectiveness improvements achieved by using the selection of correct devices. Finally, experimental results on the converter performances such as switching transients, power losses and thermal behavior are carried out

Relationship between global end-diastolic volume and cardiac output in critically ill infants and children.

OBJECTIVE: The objective of this study was to investigate possible correlations between the preload index global end-diastolic volume (GEDV) and the indexes of cardiac function, cardiac index, and stroke volume index in critically ill pediatric patients. The aim was to evaluate whether GEDV may help in the decision-making process concerning volume loading. DESIGN: Prospective clinical study. SETTING: Pediatric intensive care unit of the Bambino Gesù Children's Research Hospital. PATIENTS: Seventy patients, 40 male and 30 female, mean age 62 +/- 41 months (range 5-156 months), divided into six groups: group A, hemorrhagic shock, ten cases; group B, head injury, 21 cases; group C, septic shock, ten cases; group D, encephalitis, ten cases; group E, respiratory failure, nine cases; group F, cardiogenic shock, ten cases. INTERVENTIONS: All patients received volumetric hemodynamic monitoring following initial resuscitation and every 4 hrs thereafter or whenever a hemodynamic deterioration was suspected. During the cumulative in-hospital stay, a total 1,184 sets of measurements were done. MEASUREMENTS AND MAIN RESULTS: Findings are consistent with a statistically significant linear correlation of GEDV with cardiac index and stroke volume index in hemorrhagic shock (group A) (R2 = .647, p .0001; R2 = .738, p .0001) and cardiogenic shock (group F) (R2 = .645, p .0001; R2 = .841, p .0001). CONCLUSIONS: GEDV may potentially be a useful guide to treatment in preload-dependent conditions, such as hemorrhagic and cardiogenic shock. In the other groups where there is little relationship between preload and cardiac function indexes, the influence of non-preload-dependent mechanisms on cardiac output is certainly more significant

Derivation of transfer parameters for use within the ERICA Tool and the default concentration ratios for terrestrial biota

An ability to predict radionuclide activity concentrations in biota is a requirement of any method assessing the exposure of biota to ionising radiation. Within the ERICA Tool fresh weight whole-body activity concentrations in organisms are estimated using concentration ratios (the ratio of the activity concentration in the organism to the activity concentration in an environmental media). This paper describes the methodology used to derive the default terrestrial ecosystem concentration ratio database available within the ERICA Tool and provides details of the provenance of each value for terrestrial reference organisms. As the ERICA Tool considers 13 terrestrial reference organisms and the radioisotopes of 31 elements, a total of 403 concentration ratios were required for terrestrial reference organisms. Of these, 129 could be derived from literature review. The approaches taken for selecting the remaining values are described. These included, for example, assuming values for similar reference organisms and/or biogeochemically similar elements, and various simple modelling approaches

Bone Tissue Engineering Using Human Cells: A Comprehensive Review on Recent Trends, Current Prospects, and Recommendations

The use of proper cells for bone tissue engineering remains a major challenge worldwide. Cells play a pivotal role in the repair and regeneration of the bone tissue in vitro and in vivo. Currently, a large number of differentiated (somatic) and undifferentiated (stem) cells have been used for bone reconstruction alone or in combination with different biomaterials and constructs (e.g., scaffolds). Although the results of the cell transplantation without any supporting or adjuvant material have been very effective with regard to bone healing. Recent advances in bone scaffolding are now becoming new players affecting the osteogenic potential of cells. In the present study, we have critically reviewed all the currently used cell sources for bone reconstruction and discussed the new horizons that are opening up in the context of cell-based bone tissue engineering strategies

Evidence for a differentiated chromosomal race north of classical south European refuge areas in the garden dormouse Eliomys quercinus

The dormouse Eliomys quercinus is a forest rodent undergoing long periods of winter hibernation. The species presents a surprisingly large diversity of chromosomal races, which geographic distribution was shown recently to predate the Pleistocene glaciations. Previously reported data on the karyotypes of the garden dormouse in France come from the northeast of the country, where the 2N050 race occurs. New data are presented from specimens trapped near the Atlantic coast (departments of Vendée and Charente-Maritime), in the Pyrenees, the Alps and in the Massif Central. The French Alpine chain, close to the Italian border, is inhabited by the 2N054 race. A karyotype with 2N048 chromosomes, of Iberian type, is found north of the Pyrenees, near the central Atlantic coast and also in the south of the Massif Central, whereas the 2N050 race occurs in the north of the massif. A hybrid between these two races (2N049) was found in Vendée. These facts reveal that neither the Pyrenees nor the Alps constitute a biogeographic barrier to the dormouse and strongly suggest that the present population of northern France derives from a postglacial recolonisation movement initiated in the southernmost regions of France or in the Rhône valley.project no. POCTI/BSE/36626/9