Formation of oxynitride layers in a RF plasma planar reactor for future Si and SiC MOS structures

Experiments presented in this work are a part of an extended study that examines the possibility of fabrication of oxynitride layers for future Si and SiC MOS structures by nitrogen implantation from RF plasma and subsequent plasma oxidation process. In order to avoid analysis of more complex SiC MOS devices, at this stage, the experiments were performed using silicon substrates. The obtained layers were characterized by means of ellipsometry, XPS and SIMS. The results of electrical characterization of MOS test structures fabricated with investigated layers used as gate dielectric, are also discussed.     

Fibrinogen receptor (GPIIb-IIIa) antagonists derived from 5,6-bicyclic templates. Amidinoindoles, amidinoindazoles, and amidinobenzofurans containing the N-alpha-sulfonamide carboxylic acid function as potent platelet aggregation inhibitors

A series of highly potent and specific fibrinogen receptor antagonists have been discovered and optimized through structural modification of the novel amidinoindole and benzofuran compounds, I and II. Systematic linker optimization afforded the amidinobenzofuran-containing inhibitor 29, which displayed an IC50 value of 250 nM in platelet aggregation assays. Attempts to enhance activity by modification of the beta-position of the beta-alanyl carboxylate group of 29 had only a modest effect on inhibitory activity in aggregation assays. Analogues prepared to enhance the activity by conformational restriction were also found to be equally or less potent. In contrast, modification at the alpha-position of the beta-alanyl carboxylate group resulted in the identification of extremely potent and novel amidinobenzofuran-containing derivatives 46-49. Reexamination of 5,6-bicyclic aromatic nucleus led to the further identification of amidinoindole- and amidinoindazole-containing derivatives 53-55. These analogues, 46-49 and 53-55, exhibited potent in vitro activity with IC50 values of 25-65 nM in platelet aggregation assays and an IC50 value of 2 nM in fibrinogen binding assays and demonstrated a selectivity of > 50,000-fold for GPIIb-IIIa versus the most closely related integrin, the vitronectin receptor, alpha v beta 3.     

Elemental bioimaging in kidney by LA-ICP-MS as a tool to study nephrotoxicity and renal protective strategies in cisplatin therapies

A laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)-based methodology is presented for Pt, Cu, and Zn bioimaging on whole kidney 3 μm sagittal sections from rats treated with pharmacological doses of cisplatin, which were sacrificed once renal damage had taken place. Pt turned out to accumulate in the kidney cortex and corticomedullary junction, corresponding to areas where the proximal tubule S3 segments (the most sensitive cells to cisplatin nephrotoxicity) are located. This demonstrates the connection between platinum accumulation and renal damage proved by histological examination of HE-stained sections and evaluation of serum and urine biochemical parameters. Cu and Zn distribution maps revealed a significant displacement in cells by Pt, as compared to control tissues. A dramatic decrease in the Pt accumulation in the cortex was observed when cilastatin was coadministered with cisplatin, which can be related to its nephroprotective effect. Excellent imaging reproducibility, sensitivity (LOD 50 fg), and resolution (down to 8 μm) were achieved, demonstrating that LA-ICP-MS can be applied as a microscopic metal detector at cellular level in certain tissues. A simple and quick approach for the estimation of Pt tissue levels was proposed, based on tissue spiking.     

Photocatalytic activity of thin TiO2 films deposited using sol–gel and plasma enhanced chemical vapor deposition methods

Thin titanium dioxide films, deposited using RF PECVD and sol–gel techniques, were studied comparatively with respect to their bactericidal as well as self-cleaning properties. The effect of the deposition process on film morphology, chemical and crystalline structure, bactericidal activity and hydrophilic properties was investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), surface profilometry, optical microscopy and contact angle measurements. It was found that the bactericidal activity of amorphous TiO₂ films, produced using the RF PECVD method, as either comparable to or better than those of crystalline (anatase) films deposited by means of the sol–gel technique. One reason for such advantageous behavior of plasma deposited materials is thought to be their substantially higher surface roughness, as revealed by AFM measurements. The hydrophilic effect, induced with UV irradiation, was strongest in the case of sol–gel films, but the RF PECVD synthesized coatings were found to be only slightly less hydrophilic. The conclusion follows that both sol–gel and RF PECVD techniques are equally capable of producing titanium dioxide films of high photocatalytic quality.     

Corn grist adjunct – application and influence on the brewing process and beer quality

In the brewing industry, barley malt is often partially replaced with adjuncts (unmalted barley, wheat, rice, sorghum and corn in different forms). It is crucial, however, to preserve constant quality in the beer to meet the expectations of consumers. In this work, how the addition of corn grist (10 and 20%) influences the quality of wort and beer was examined. The following parameters were analysed: wort colour, dimethyl sulphide (DMS) and protein content, non‐fermentable extract, extract drop during fermentation, alcohol content and the attenuation level of the beer, together with filtration performance. The samples (all‐malt, and adjunct at 10 and 20% corn grist) were industrial worts and the beers produced in a commercial brewery (3000 hL fermentation tanks). The application of 10 and 20% corn grist had an effect on the wort colour, making it slightly lighter (11.1 and 10.5°EBC, respectively) than the reference barley malt wort (12.2°EBC). The free amino nitrogen level, DMS and non‐fermentable extract were significantly lower in the worts produced with the adjunct; the alcohol content and attenuation levels were higher in the beers produced with adjunct. The use of corn grist, at the level of up to 20% of total load, appears to affect some of the technological aspects of wort and beer production, but it does not significantly influence the final product characteristics. Copyright © 2014 The Institute of Brewing & Distilling     

Quantitative submonolayer spatial mapping of Arg-Gly-Asp-containing peptide organomercaptan gradients on gold with matrix-assisted laser desorption/ionization mass spectrometry

Peptides containing the tripeptide sequence Arg-Gly-Asp (RGD) have the ability to bind to members of the integrin superfamily of cell-surface receptors and direct cellular adhesion and haptotaxis. The goal of this work is the development of a rapid and effective method for the quantitative submonolayer spatial composition mapping of surfaces displaying molecular assemblies of RGD-containing organomercaptan peptides on a Au surface using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-MS). Quantitation of the RGD peptide is achieved by determining the peak intensity of the protonated molecular ion, (M + H)+, relative to the (M + H)+ peak for an internal standard, which is similar chemically but with glutamic acid (E) substituted for aspartic acid (D). Using optimized sample preparation procedures, a bilinear calibration was obtained between the quantitative peak intensity ratio and the mole fraction of the RGD-containing peptide. Quantitative compositions were determined with relative standard deviations of <10%, even in the presence of 10x spot-to-spot variations in the absolute signal intensities, by using this internal standard approach. This MALDI-MS quantitative analysis method was employed to probe variable-width two-component counterpropagating electrochemically generated gradients of the two peptides, prepared by coupling in-plane electrochemical potential gradients with the electrosorption reactions of organothiols to vary the composition laterally. The measured lateral composition profiles match the quasi-linear potential gradient model and yield profiles that overlap to a high degree of fidelity in potential space. Thus, MALDI-MS spatial composition mapping should become a powerful tool for the preparation of designed surfaces facilitating the study of cellular adhesion and motility and cell-cell interactions.     

Numerische Untersuchungen zur Ermüdungsbeanspruchung vorgespannter Ringflanschstöße mit Imperfektionen

Numerical investigations on the fatigue‐relevant bolt stresses in preloaded ring flange connections with imperfections. For the structural design of preloaded bolted ring flange connections in tower‐like steel structures (e.g. chimneys or wind turbine tubular towers), the fatigue assessment of the bolts is very important. Gaps between the contact surfaces before preloading (so‐called flange imperfections) may have a negative influence on the fatigue‐relevant bolt stresses. A FE‐model for imperfect ring flanges was built up and validated by means of the results of large‐scale tubular bending tests on flange connections. With the validated FE‐model, a parametric study on imperfectly simulated L‐flange connections having realistic dimensions of typical wind turbine towers was performed. The results enable differentiating the various gaping forms with regard to their negative influence on the bolt fatigue. This influence may not be neglected when assessing the fatigue safety of the bolts.     

Ermüdungssichere Bemessung vorgespannter Ringflanschstöße unter Berücksichtigung von Flanschimperfektionen

Fatigue design of preloaded ring flange connections taking flange imperfections into account. The fatigue life of the bolts in preloaded ring flange connections may drastically drop when there are gaps between the flange contact surfaces before preloading the bolts (“flange imperfections”). Preloaded ring flange connections are often used as site joints in tower‐like steel structures, e.g. in tubular towers of wind turbines (WEA). The fatigue‐detrimental effects of flange imperfections have been comprehensively investigated at the University of Essen. The conclusions to be drawn from it with regard to a fatigue‐safe design are described and commented in the present paper, based on the relevant rules in the new DIBt‐guidelines for WEA. Two calculation models are presented how to take flange imperfections approximately into account in the fatigue design. For the redeveloping of a site joint, which during erection turns out to be too imperfect, the method of packing the gaps is discussed.     

Characteristics of four-channel Cherenkov-type detector for measurements of runaway electrons in the ISTTOK tokamak

A diagnostics capable of characterizing the runaway and superthermal electrons has been developing on the ISTTOK tokamak. In previous paper, a use of single-channel Cherenkov-type detector with titanium filter for runaway electron studies in ISTTOK was reported. To measure fast electron populations with different energies, a prototype of a four-channel detector with molybdenum filters was designed. Test-stand studies of filters with different thicknesses (1, 3, 7, 10, 20, 50, and 100?μm) have shown that they should allow the detection of electrons with energies higher than 69, 75, 87, 95, 120, 181, and 260 keV, respectively. First results of measurements with the four-channel detector revealed the possibility to measure reliably different fast electrons populations simultaneously.