Untersuchung des einflusses molekularer parameter auf morphologie und eigenschaften von polyethylenen niedriger dichte

Based on the example of PE-LD grades and on model substances obtained by preparative fractionation (fractions in the molecular weight range M?_w = 1.2 ? 390·10⁴ g/mol), comprehensive investigations regarding the problems of structure/properties have been carried out. The correlations of M?_w with 15 physical and application technological perameters have been investigated taking into account the reaction mechanism during the manufacturing of PE-LD in the tubular and agitated autoclave reactor, resulting in the formation of so-called primary structure perameters M?_n, M?_w, molar mass distribution, short chain branching and long chain branching. For the interpretation of the results, among other factors, also the morphological conditions have been taken into consideration, which in connection with the molecular parameters reveal — for specific M?_w-ranges — strong changes and saturation ranges, resp., for the physical and application technological properties.     

A simple method for the objective characterisation of fabric softness. Part 1: Influence of bleaching,dyeing and crosslinking of wool*

A simple method for the characterisation of fabric softness using a conventional tensile tester and a special measurement device has been developed. The method is demonstrated to be especially useful in detecting changes in softness of a given substrate due to different treatments. The results obtained, particularly hysteresis at 75% of the maximum extension, provide a good correlation with subjective ranking for samples that are subjectively distinguishable; they also differentiate well between samples which seem subjectively indistinguishable. Screening tests were carried out, mainly on wool fabrics, to find the effect of different treatments such as oxidative (alkaline and acidic) and reductive (Blankit IN) bleaching, dyeing with acid and a 1:2 metal complex, chrome and (mono and bi)reactive dyes, the effect of the antisetting agent Basolan AS (BASF) and of crosslinking with Irgasol HTW (CGY) on fabric softness.     

Carbohydrate content of apolipoprotein B-48 from rat chylomicrons of varying density

Monosaccharide composition was determined in apolipoprotein B-48 (apoB) of chylomicrons of rat mesenteric lymph. Chylomicrons were separated into three fractions based on density. Triglyceride and apolipoprotein content were determined in each. ApoB was isolated and quantified using precipitation with isopropanol. Chylomicrons were collected in lymph under normal conditions, and with Poloxalene 2930 when chylomicron secretion was inhibited. Most of the triglyceride was carried in the least dense fraction, while the highest apoB content was in the most dense fraction under normal conditions. Mannose and galactosamine contents of apoB were similar in all fractions while contents of both glucosamine and galactose were highest in the least dense fraction. When chylomicron secretion was inhibited by Poloxalene, the amount of triglyceride recovered in the least dense fraction was significantly reduced. Despite the inhibition of lipid transport in the least dense fraction of chylomicrons by Poloxalene, there was little change in apoB recoveries and in the relative content of various monosaccharides in the apoB from each of the three fractions as compared to results obtained during lipid absorption under normal conditions. In conclusion, carbohydrate composition of apoB of chylomicrons is heterogeneous and varies with chylomicron density.     

Crystal structure of TNF-alpha mutant R31D with greater affinity for receptor R1 compared with R2

Crystal structures have been determined of recombinant human tumor necrosis factor-alpha (TNF-alpha) and its R31D mutant that preferentially binds to TNF receptor R1 with more than seven times the relative affinity of binding to receptor R2. Crystals of the wild-type TNF were of space group P4(1)2(1)2 and had unit cell dimensions of a = b = 94.7 and c = 117.4 A. Refinement of the structure gave an R-factor of 22.3% at 2.5 A resolution. The crystals of TNF R31D mutant diffracted to 2.3 A resolution, and were of identical space group to the wild type with unit cell dimensions of a = b = 95.4 and c = 116.2 A, and the structure was refined to an R-factor of 21.8%. The trimer structures of the wild-type and mutant TNF were similar with a root mean square (r.m.s.) deviation of 0.56 A for Calpha atoms; however, the subunits within each trimer were more variable with an average r.m.s. deviation of 1.00 A on Calpha atoms for pairwise comparison of subunits. Model complexes of TNF with receptors R1 and R2 have been used to predict TNF-receptor interactions. Arg31 in all three subunits of wild-type TNF is predicted to form an ionic interaction with the equivalent glutamic acid in both receptors R1 and R2. Asp31 of the TNF R31D mutant is predicted to interact differently with the two receptors. The side chain of Asp31 in two subunits of the TNF mutant is predicted to form hydrogen bond interactions with Ser59 or Cys70 of R1, while it has no predicted interactions with R2. The loss of three strong ionic interactions of Arg31 and the electrostatic repulsion of Asp31 with Glu in the receptors is consistent with the reduced binding of the R31D mutant to both receptors relative to wild-type TNF. The replacement of these ionic interactions by two weaker hydrogen bond interactions between Asp31 of the R31D mutant and R1, compared with no interactions with R2, is in agreement with the observed preferential binding of the R31D mutant to R1 over R2. Analysis of the structure and function of receptor-discriminating mutants of TNF will help understand the biological role of TNF and facilitate its use as an antitumor agent.      

Application of the SIMS Method in Studies of Cr Segregation in Cr-Doped CoO: I, Aspects of Quantitative Analysis

Aspects of calibration of intensities of SIMS secondary ions vs concentration as well as sputtering time vs depth are considered for Cr-doped CoO. Advantages and limitations of the SIMS method in quantitative analysis of segregation-induced concentration profiles in oxide crystals are discussed. The studies indicate a substantial effect due to charging the surface during sputtering. The depth calibration was performed by using the Ta₂O₅/Ta system as a standard. Good depth resolution was revealed. The calibration dependence of Cr intensities on concentration is characterized by a wide scatter of data caused by charging the surface. Very good shape reproducibility of the intensity ratio vs depth profiles was revealed. Therefore, normalized intensity ratios can be used for calibration.     

Chalkonaziridine. IV. Vergleich des spektroskopischen und massenspektrometrischen Verhaltens von trans-Chalkonaziridinen und trans-Chalkonepoxiden

Chalcone Aziridines. IV. Comparison of Spectroscopical and Mass Spectrometrical Behavior of trans-Chalcone Aziridines and trans-Chalcone Epoxides The aziridines 1 were compared with epoxides 2 by their i.r. and n.m.r. spectroscopical behavior and the threemembered ring electron densities. In the masse spectra we found not only identical path-ways i. e. the formation of M^⊕ and Ar₂CH^⊕ ions and onium or aryl fragmentation, but also differences as the formation of [M–17]^⊕ ions for 1 and carbonyl rearrangements for 2 .     

Substituenteneffekte in den 13C-NMR-Spektren von diastereomeren Chalkondihalogeniden. VIII. Untersuchungen an α- und β-Halogendihydrochalkonen und Berechnung von 13C-chemischen Verschiebungen bei diastereomeren Chalkondihalogeniden und Chalkonhalogenhydrinen

Substituent Effects in ¹³C-N.M.R. Spectra of Diastereomeric Chalcone Dihalogenides. VIII. Investigations of α- and β-Halogene Dihydrochalcones and Calculation of ¹³C-chemical Shifts of Diastereomeric Chalcone Dihalogenides and Chalcone Halogenohydrins The chemical shifts of C-α and C-β in the ¹³C-n.m.r. spectra are determined and compared with calculated values from an incremental system and Taft relationship. The correlations are extended for erythro and threo isomers of halohydrins and diastereometric dihalogenides 6 – 18 . The chemical shifts of C-α and C-β atoms of 6 – 18 are described in the dependence of the shifts calculated by an incremental system. Excellent correlations allowed the computation of chemical shifts of C-α and C-β for diastereomeric α,β-disubstituted dihydrochalcone derivatives likely 6 – 18 in advance.     

二维机读ID质量的要素

现在,几乎所有产品都需要有唯一的ID（身份证明）用以跟踪,这一用途的标签通常是由自动的在线系统印出的。Code 39码和Code 128码作为标识产品ID的条形码已经使用很多年了,然而,当今技术的发展和质量管理的需求不可避免的对产品ID提出了更高的要求,有以下三方面的因素需要考虑。