Siegfried Selberherr mit Erwin Schr?dinger-Preis gewürdigt

SciencenewsHohe auszeichnung der ?AW

Siegfried Selberherr mit Erwin Schr?dinger-Preis gewürdigt     

Formation of cBN nanocrystals by He+ implantation into hBN

The structural modifications of polycrystalline hexagonal boron nitride implanted with He⁺ beams at energies between 200 keV and 1.2 MeV to fluences of 1.0 × 10¹⁷ ions cm^? 2 were investigated using micro-Raman spectroscopy. The measured Raman spectra show evidence of implantation-induced structural transformations from the hexagonal phase to nanocrystalline cubic boron nitride, rhombohedral boron nitride and amorphous boron nitride phases. The first-order Longitudinal-Optical cubic boron nitride phonon was observed to be downshifted and asymmetrically broadened and this was explained using the spatial correlation model coupled with the high ion implantation-induced defect density.     

Donor Heart Preservation with Hydrogen Sulfide: A Systematic Review and Meta-Analysis

Preclinical studies have shown that postconditioning with hydrogen sulfide (H₂S) exerts cardioprotective effects against myocardial ischemia-reperfusion injury (IRI). The aim of this study was to appraise the current evidence of the cardioprotective effects of H₂S against IRI in order to explore the future implementation of H₂S in clinical cardiac transplantation. The current literature on H₂S postconditioning in the setting of global myocardial ischemia was systematically reviewed and analyzed, performing meta-analyses. A literature search of the electronic databases Medline, Embase and Cinahl identified 1835 studies that were subjected to our pre-defined inclusion criteria. Sixteen studies were considered eligible for inclusion. Postconditioning with H₂S showed significant robust effects with regard to limiting infarct size (standardized mean difference (SMD) = −4.12, 95% CI [−5.53–−2.71], p < 0.00001). Furthermore, H₂S postconditioning consistently resulted in a significantly lower release of cardiac injury markers, lower levels of oxidative stress and improved cardiac function. Postconditioning with slow-releasing H₂S donors offers a valuable opportunity for novel therapies within cardiac preservation for transplantation. Before clinical implication, studies evaluating the long-term effects of H₂S treatment and effects of H₂S treatment in large animal studies are warranted.     

The hepatopulmonary syndrome: radiologic findings in 10 patients

OBJECTIVE: The purpose of this study was to review the radiologic manifestations of the hepatopulmonary syndrome. MATERIALS AND METHODS: We retrospectively reviewed clinical records, chest radiographs, 99m Tc-macroaggregated albumin (MAA) perfusion lung scans, chest CT scans, and pulmonary angiograms of 10 patients with proven hepatopulmonary syndrome. RESULTS: Chest radiographs showed basilar, medium-sized (1.5-3.0 mm) nodular or reticulonodular opacities in all cases. CT was done in eight cases and showed basilar dilatation of lung vessels with a larger than normal number of visible branches. The vascular basis for these opacities was best appreciated on conventional CT scans of 10-mm sections. No individual arteriovenous malformations were seen on CT scans. High-resolution CT scans showed no evidence of interstitial fibrosis. 99mTc-MAA perfusion lung imaging, done in seven patients, showed pulmonary arteriovenous shunting in five. Contrast echocardiography confirmed intrapulmonary shunting in these five patients. Pulmonary angiography, done in four cases, showed subtle distal vascular dilatation in two and moderate dilatation with early venous filling in two but did not reveal any individual arteriovenous malformations. CONCLUSION: Chest radiographs in hepatopulmonary syndrome usually show bibasilar nodular or reticulonodular opacities. Conventional CT shows that these opacities represent dilated lung vessels. High-resolution CT is useful in excluding pulmonary fibrosis or emphysema as the cause of these opacities. 99mTc-MMA perfusion imaging or contrast echocardiography can be used to confirm intrapulmonary arteriovenous shunting.     

Local ice application in therapy of kinetic limb ataxia. Clinical assessment of positive treatment effects in patients with multiple sclerosis

Upper limb ataxia is one of the most disabling symptoms of patients with multiple sclerosis (MS). There are some clinically tested therapeutic strategies, especially with regard to cerebellar tremor. But most of the methods used for treatment of limb ataxia in physiotherapy and occupational therapy are not systematically evaluated, e.g. the effect of local ice applications, as reported by MS patients and therapists, respectively. We investigated 21 MS patients before and in several steps 1 up to 45 min after cooling the most affected forearm. We used a series of 6 tests, including parts of neurological status and activities of daily living as well. At each step skin temperature and nerve conduction velocity were recorded. All tests were documented by video for later offline analysis. Standardized evaluation was done by the investigators and separately by an independent second team, both of them using numeric scales for quality of performance. After local cooling all patients showed a positive effect, especially a reduction of intentional tremor. In most cases this effect lasted 45 min, in some patients even longer. We presume that a decrease in the proprioceptive afferent inflow-induced by cooling-may be the probable cause of this reduction of cerebellar tremor. Patients can use ice applications as a method of treating themselves when a short-time reduction of intention tremor is required, e.g. for typing, signing or self-catheterization.     

An investigation of subsynchronous resonance by fourier transformation

This paper shows how additional insight into subsynchronous resonance of a series capacitive compensated turbogenerator power system can be obtained by a Fourier analysis of the time domain waveforms. These waveforms are generated by digital computer simulation of the IEEE bench mark model and then sampled, filtered and transformed into the frequency domain which shows up all the mechanical and electrical resonant modes. Different types of disturbances at different load values are used to evaluate their effect on the values of the resonant frequencies.     

Inhibition of copper corrosion in acidic chloride pickling solutions by 5-(3-aminophenyl)-tetrazole as a corrosion inhibitor

Inhibition of copper corrosion in acidic chloride pickling (0.5 M HCl) solutions by 5-(3-Aminophenyl)-tetrazole (APT) as a corrosion inhibitor has been studied using potentiodynamic polarization, chronoamperometry (CA), electrochemical impedance spectroscopy (EIS), weight-loss and Raman spectroscopy investigations. Electrochemical measurements showed that the presence of APT and the increase of its concentration significantly decrease the cathodic, anodic, and corrosion currents as well as corrosion rates. This effect also decreases the dissolution currents of copper at 200 mV vs. Ag/AgCl, and greatly increases surface and polarization resistances and inhibition efficiency as indicated by CA and EIS measurements. Weight-loss data revealed that the corrosion rate of copper decreases to a minimum and the inhibition efficiency increases to a maximum in the presence of APT and upon increasing of its concentration even after 72 h of copper coupons immersion. Comparing the Raman spectrum obtained on the copper surface after its immersion in HCl solution containing 1.0 mM APT for 72 h to the spectrum obtained for the solid APT alone indicated that APT molecules inhibit the corrosion of copper via their adsorption onto its surface.     

Structural and metabolic changes in femaleSchistosoma mansoni following male stimulation

Pairing of males and females from single-sex infections results in the multiplication and differentiation of undifferentiated cells of the vitelline lobule culminating in the production of mature vitelline cells involved in egg shell formation. These changes are accompanied by increases in the rate of uptake of tyrosine, thymidine, and an increased accumulation of calcium.     

The strain aging characteristics of reinforcing steel with a range of vanadium contents

The strain aging characteristics of a reinforcing steel made with vanadium ranging between zero and 0.1 pct and with two aluminum levels have been investigated for the ashot rolled condition. It has been shown that vanadium contents of 0.04 to 0.06 pct (a V/N ratio of 7 to 9) will result in the combination of almost all the active nitrogen as vanadium nitride and suppresses natural strain aging. Vanadium in excess of this level results in the precipitation of vanadium carbide and the consequential precipitation hardening gives an increase in the yield strength, tensile strength, and impact transition temperature without imparting further beneficial effect with regard to strain aging. The mechanical properties have been shown to be generally unaffected by the two different aluminum levels, and no grain refinement resulted from either the vanadium or aluminum additions. This absence of grain refinement and the precipitation hardening results in an increase in the impact transition temperature with increasing vanadium content, although this increase is initially slow whilst the active nitrogen content is being reduced.     

Metals in soils of children's urban environments in the small northern European city of Uppsala

Metals occur naturally in soil, but contents are generally increased in the urban environment due to anthropogenic activities. The presence of elevated metals in soils of the urban environment has been recognized as an important source of metal intake in children and is linked to elevated metal levels in children's blood. Several metals have undesirable health effects, especially on children due to their still developing nervous system and small body volumes. Playgrounds are where urban children spend most of their time outdoors and are also where children most frequently come in contact with soil. Elevated contents of metals in playgrounds are therefore of great concern for children's wellbeing. This study investigates the soil metal content of 25 playgrounds located in different land use areas in urban Uppsala, Sweden's fourth largest city. Uppsala covers an area of approximately 100 km2 and has a population of 136,000. The soil samples were analysed for 12 metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, W, Zn) using aqua regia. Median metal contents were found to be 1.8, 3.4, 0.21, 32, 25, 2.5, 0.14, 494, 19, 26, 0.35 and 84 mg kg(-1) soil for each of the above metals, respectively. The median clay content was around 20% while the organic matter content was measured by loss on ignition at a median of 8%. The land use areas included industrial land, the city center, road verges, natural land and former industrial land. The results showed that land use did not have the expected large influence on the total metal contents of the soils tested. The clay content together with the age of the site proved to be a more important factor. Sites with elevated clay contents had in general elevated metal contents, which were explained by the relatively high adsorption capacity of clay particles. The soils at sites where land use had not been altered since the 1800s had increased metal contents compared to playgrounds constructed in the late 1900s. The immobility of metals once they had entered the soil system was the reason for increased metal content in soils of old playgrounds. It was concluded that in cities with few internal pollution sources, the soil characteristics of the site and the time the soil has been on-site to accumulate metal residues become important factors in determining the soil metal content.