Very low surface recombination velocities on p-type silicon wafers passivated with a dielectric with fixed negative charge

Surface recombination velocities as low as 10 cm/s have been obtained by treated atomic layer deposition (ALD) of Al₂O₃ layers on p-type CZ silicon wafers. Low surface recombination is achieved by means of field induced surface passivation due to a high density of negative charges stored at the interface. In comparison to a diffused back surface field, an external field source allows for higher band bending, that is, a better performance. While this process yields state of the art results, it is not suited for large-scale production. Preliminary results on an industrially viable, alternative process based on a pseudo-binary system containing Al₂O₃ are presented, too. With this process, surface recombination velocities of 500–1000 cm/s have been attained on mc-Si wafers.     

Manipulating the Level of Sensorimotor Stimulation during LI-rTMS Can Improve Visual Circuit Reorganisation in Adult Ephrin-A2A5-/- Mice

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that has the potential to treat a variety of neurologic and psychiatric disorders. The extent of rTMS-induced neuroplasticity may be dependent on a subject’s brain state at the time of stimulation. Chronic low intensity rTMS (LI-rTMS) has previously been shown to induce beneficial structural and functional reorganisation within the abnormal visual circuits of ephrin-A2A5^-/- mice in ambient lighting. Here, we administered chronic LI-rTMS in adult ephrin-A2A5^-/- mice either in a dark environment or concurrently with voluntary locomotion. One day after the last stimulation session, optokinetic responses were assessed and fluorescent tracers were injected to map corticotectal and geniculocortical projections. We found that LI-rTMS in either treatment condition refined the geniculocortical map. Corticotectal projections were improved in locomotion+LI-rTMS subjects, but not in dark + LI-rTMS and sham groups. Visuomotor behaviour was not improved in any condition. Our results suggest that the beneficial reorganisation of abnormal visual circuits by rTMS can be significantly influenced by simultaneous, ambient visual input and is enhanced by concomitant physical exercise. Furthermore, the observed pathway-specific effects suggest that regional molecular changes and/or the relative proximity of terminals to the induced electric fields influence the outcomes of LI-rTMS on abnormal circuitry.     

Skin tests in the diagnosis of eruptions caused by betalactams

The assumption that the amount of rainfall in the summer months influences the frequency of TBE is based on the fact that the determining factor for the existence, development and activity of Ixodes ricinus is relative air humidity (RH) and the finding that low RH negatively influences dynamics of infection and infection rate of I. ricinus with TBE virus. A higher incidence of TBE then develops due to the coincidence of increased activity of ticks and recreational activity of humans after an intense prolonged rainfall. This presumption was verified by comparing the dynamics of rainfall as an indicator of RH in the tick environment with concomitant seasonal fluctuations of TBE incidence in humans. The total monthly rainfall in two regions of the Czech Republic was compared with data on the incidence of TBE in each respective region and period. Furthermore, in the district of Ceské Bud?jovice, typical by high prevalence of this disease, a detailed follow-up was carried out by decades. The comparisons were made between April and October from 1993 to 1995. The values of both variables were related to their long-term averages estimated within each particular period and region. Monthly data were analyzed for the Central Bohemian Region and the South Bohemian Region, both with a high incidence of TBE. The July above-average incidence of TBE was preceded by an above-average rainfall in June. If there was a below-average rainfall, there was a below-average incidence of TBE afterwards. Whenever, there was an above-average rainfall in August then there was an above average incidence of TBE in September, in the opposite case, no September peak of TBE occurred. The follow-up at ten-day intervals shows that any above-average rainfall was followed by an increased incidence of TBE, in every other ten-day period or two. This time shift is due to the incubation period, and partly also to the scattered attacks by ticks during the period of increased RH. The relationship found could be useful for the short-term prognosis of TBE incidence as well as for individual prevention of this serious infection by taking special care when going outdoors after heavy rain.     

Low cost surface passivation for p-type mc-Si based on pseudobinary alloys (Al2O3)x(TiO2)1−x

The conventional process for back side passivation with full face Al screen printing layer is not suitable for very thin multicrystalline (mc-Si) solar cells and approaches to new technological processes are searched for. More investigations have been concentrated on local aluminum contacts and passivation coatings with different layers on mc-Si wafers. The aim of this work is to prove that (Al₂O₃)_x(TiO₂)_1−x is one promising candidate to be applied as passivation layer on multicrystalline Si. Investigations were performed on dielectric films of pseudobinary alloy (PBA) (Al₂O₃)_x(TiO₂)_1−x, prepared by chemical solution deposition known initially as sol–gel method. It was determined that their optical, dielectric and electrophysical properties are suitable for applications of these layers as back side surface passivation for thin multicrystalline silicon cells.     

Fast and air stable near-infrared organic detector based on squaraine dyes

In search for an organic material suitable for the detection of near-infrared electromagnetic radiation and at the same time capable of air stable operation of related devices, so to address the many applications envisaged with this technology (remote control, chemical/biological sensing, optical communication, spectroscopic and medical instruments), we explore the performance of a blend of hydrazone end-capped symmetric squaraines and phenyl C₆₁ butyric acid methyl ester. We succeed in developing air stable solution-processed devices with external quantum efficiency in the NIR as high as 3.5% and response times of few hundreds of nanoseconds. Essential to these achievements has been a detailed characterization of the devices performed by correlating the optoelectronic performances to the morphology of the layers (extracted from AFM measurements) and to the charge carrier mobility (extracted from transistor structures), enabling their optimization at the chemical level, by tailoring the squaraine substitution pattern, and at the device level, by tuning the blend composition. We show that a good balance between holes and electrons mobility is essential for high EQE and fast response speed, and that a smooth morphology is mandatory to achieve long term air stability and operability with no need for encapsulation.     

Virological characterization and liver histology in HCV positive subjects with normal and elevated ALT levels

In a retrospective study of the pattern of drugs used in the initial treatment of hypertension, 300 case notes of hypertensive patients attending medical clinics at the Korle-Bu Teaching Hospital, Accra and whose treatment were initiated during the period 1973-1993, were reviewed. The mean age of patients was 55 years, mean pre-treatment systolic and diastolic pressures were 179.5 +/- 25. 5 and 108.5 +/- 14.2 mm Hg, respectively, with 85% of patients being female. The frequencies of individual drugs prescribed for the initial treatment of hypertension were: diuretics (90%), reserpine (46%), methyldopa (31%), and propranolol (30%). Single drug treatment was prescribed for 18%, two drugs for 60% and three or more (multiple drugs) for 22% of patients. The mean number of drugs per patient was 2.2 Patients prescribed multiple drugs had pre-treatment systolic and diastolic blood pressures which were significantly (p < 0.01) higher than those prescribed 2 drugs which were, in turn, higher (p < 0.001) than those prescribed single drugs. The results showed that during the period 1973-1993, diuretic based "stepped care" therapy was the main first line anti-hypertensive drug management regime. "Old" anti-hypertensive drugs were more commonly used than newer ones. The cost and availability drugs and the pretreatment blood pressure were probably the main determinants of the choice of the type and number of drugs prescribed.     

Synthesis of CdZnTeSe single crystals for room temperature radiation detector fabrication: mitigation of hole trapping effects using a convolutional neural network

Journal of Materials Science: Materials in Electronics - In this article, we report the growth of Cd0.9Zn0.1Te0.97Se0.03 (CZTS) wide bandgap semiconductor single crystals for room temperature...     

Low-cost rear side floating junction solar-cell issues on mc-Si

Rear side floating junction solar cells with localised contacts often show parasitic shunting losses. For p-type material, this is due to tunnelling that takes places between the passivating n⁺-type rear junction and the p⁺-type back surface field region underneath localised rear contacts. To avoid this, the rear metallisation and the passivation layer should electronically be separated. Alternatively, the (induced) doping concentration of these layers could be optimised. This paper discusses the constraints met upon incorporation of such lowly recombinative structures into a low-cost solar cell process on multi-crystalline Si (mc-Si) material.     

Perceived consequences and adolescent drinking: Nonlinear and interactive models of alcohol expectancies.

Nonlinear and interactive models of alcohol expectancies and drinking were investigated using survey data obtained from junior and senior high school students on 2 occasions 2 years apart. Significant nonlinear and interactive effects were found in cross-sectional analyses. First, negative expectancies were most predictive when subjective likelihood was low. Second, drinking was highest when respondents believed that (a) negative consequences were unlikely and affective enhancement was likely and (b) both affective enhancement and social facilitation were likely. A simpler linear model was adequate for predicting changes in drinking, with both negative and affective enhancement expectancies having significant longitudinal effects. The results support the importance of alcohol expectancies but suggest that the relationships between these beliefs and adolescent drinking may be complex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)