Ultrasonic Degradation of Polystyrene for Tailoring Molecular Weight and Polydispersity of Polystyrene Fragments

Ultrasonic degradation of polymers attracts more and more attention in the field of chemical recycling of polymers due to the promising opportunity to tailor molecular weight and polydispersity of the gained polymer fragments. In this work, the influence of solvent, gas atmosphere, and ultrasound amplitude on the ultrasonic degradation process of polystyrene is investigated. Therefore, an experimental procedure to perform ultrasonic degradation of polystyrene under homogeneous temperature conditions in the solvents cyclohexane and toluene under the gas atmospheres CO$_{2}$ and N$_{2}$ for different ultrasonic amplitudes was designed. It could be shown that a significant effect on the molecular weight and polydispersity of the polymer could only be revealed for N$_{2}$ and not for CO$_{2}$ atmosphere

Production of polylactic acid aerogels via phase separation and supercritical CO2_{2} drying: thermodynamic analysis of the gelation and drying process

The application range of aerogels, especially in the life-science sector, can be extended by utilizing biocompatible polymers such as polylactic acid (PLA). However, the low glass transition temperature (Tg) of PLA and the challenging gelation techniques limit the application of supercritical CO$_{2}$ (scCO$_{2}$) drying and thus the PLA-aerogel production. The aim of this work is to overcome this challenge and to provide a better understanding of the thermodynamics of the process. Therefore, the gelation of amorphous PLA (PDLLA) and semicrystalline PLA (PLLA) via thermal-induced phase separation (TIPS) was studied. To identify polymer/solvent/antisolvent ratios suitable for gelation, thermodynamic modeling (PC-SAFT) was used to describe the corresponding ternary phase diagrams. scCO$_{2}$ drying was used to preserve the mesoporous gel structure formed during the gelation. Due to the decrease in the Tg of PLA in the presence of CO$_{2}$, this could not be applied to all gels. It was found that the critical parameter to enable the scCO$_{2}$ drying of low Tg polymers is the crystallinity degree (Xc) of the polymer. Based on these results, some guidelines for producing aerogels from polymers with low Tg are formulated

Berufliche Förderung von alleinstehenden wohnungslosen Frauen: Modellprojekt im Auftrag des Bundesministeriums für Familie, Senioren, Frauen und Jugend 1998-2000

Der Bericht gibt zunächst einen Überblick über Konzeption sowie organisatorische und wirtschaftliche Rahmenbedingungen des in Karlsruhe, Kassel, Schwerin und Stuttgart durchgeführten Modellprojekts, das im Folgenden evaluiert wird. Ziel des Projekts war es, mit niederschwelligen Konzepten zur beruflichen Förderung am modernisierten Verständnis der Hilfe zur Arbeit des Par. 72 BSHG anzusetzen und die arbeitsmarktpolitischen Angebote der verschiedenen Sozialleistungsträger so zu kombinieren, dass sich vor allem jüngere Frauen langfristig wieder ein wirtschaftlich selbständiges Leben aufbauen können. Das Projekt traf auf eine hohe Motivation bei den Teilnehmerinnen und kann als Erfolg gewertet werden. Die Teilnehmerinnen erwiesen sich als beschäftigungsfähig und reintegrierbar. Sie wiesen eine hohe Bildungsmotivation und ein hohes Interesse an betrieblicher Erprobung auf. Alle Angebote des Projekts wurden doppelt genutzt (berufliche Weiterentwicklung, Überwindung schwieriger Lebenslagen). Als unabdingbare Erfolgsvoraussetzung erwies sich die sozialpädagogische Begleitung. (ICE

Liquid‐Liquid Equilibrium and Interfacial Properties of the System Water + Hexylacetate + 1‐Hexanol

Experimental and theoretical investigations of the phase diagram and the interfacial tension are presented. The theoretical framework was able to predict the phase behavior and the interfacial tension with a high accuracy, where only binary experimental data enter the model parameter. The theory permits the calculation of the concentration profiles across the interface. The profiles show that 1-hexanol will be enriched, which was expected. In same circumstances a competition between hexylacetate and 1-hexanol was figured out leading to slight minima in the profile of 1-hexanol

Immunity status of adults and children against poliomyelitis virus type 1 strains CHAT and Sabin (LSc-2ab) in Germany

<p>Abstract</p> <p>Background</p> <p>In October 2007, the working group CEN/TC 216 of the European Committee for standardisation suggested that the Sabin oral poliovirus vaccine type 1 strain (LSc-2ab) presently used for virucidal tests should be replaced by another attenuated vaccine poliovirus type 1 strain, CHAT. Both strains were historically used as oral vaccines, but the Sabin type 1 strain was acknowledged to be more attenuated. In Germany, vaccination against poliomyelitis was introduced in 1962 using the oral polio vaccine (OPV) containing Sabin strain LSc-2ab. The vaccination schedule was changed from OPV to an inactivated polio vaccine (IPV) containing wild polio virus type 1 strain Mahoney in 1998. In the present study, we assessed potential differences in neutralising antibody titres to Sabin and CHAT in persons with a history of either OPV, IPV, or OPV with IPV booster.</p> <p>Methods</p> <p>Neutralisation poliovirus antibodies against CHAT and Sabin 1 were measured in sera of 41 adults vaccinated with OPV. Additionally, sera from 28 children less than 10 years of age and immunised with IPV only were analysed. The neutralisation assay against poliovirus was performed according to WHO guidelines.</p> <p>Results</p> <p>The neutralisation activity against CHAT in adults with OPV vaccination history was significantly lower than against Sabin poliovirus type 1 strains (Wilcoxon signed-rank test P < 0.025). In eight sera, the antibody titres measured against CHAT were less than 8, although the titre against Sabin 1 varied between 8 and 64. Following IPV booster, anti-CHAT antibodies increased rapidly in sera of CHAT-negative adults with OPV history. Sera from children with IPV history neutralised CHAT and Sabin 1 strains equally.</p> <p>Conclusion</p> <p>The lack of neutralising antibodies against the CHAT strain in persons vaccinated with OPV might be associated with an increased risk of reinfection with the CHAT polio virus type 1, and this implies a putative risk of transmission of the virus to polio-free communities. We strongly suggest that laboratory workers who were immunised with OPV receive a booster vaccination with IPV before handling CHAT in the laboratory.</p

Large scale multifactorial likelihood quantitative analysis of BRCA1 and BRCA2 variants: An ENIGMA resource to support clinical variant classification

The multifactorial likelihood analysis method has demonstrated utility for quantitative assessment of variant pathogenicity for multiple cancer syndrome genes. Independent data types currently incorporated in the model for assessing BRCA1 and BRCA2 variants include clinically calibrated prior probability of pathogenicity based on variant location and bioinformatic prediction of variant effect, co-segregation, family cancer history profile, co-occurrence with a pathogenic variant in the same gene, breast tumor pathology, and case-control information. Research and clinical data for multifactorial likelihood analysis were collated for 1,395 BRCA1/2 predominantly intronic and missense variants, enabling classification based on posterior probability of pathogenicity for 734 variants: 447 variants were classified as (likely) benign, and 94 as (likely) pathogenic; and 248 classifications were new or considerably altered relative to ClinVar submissions. Classifications were compared with information not yet included in the likelihood model, and evidence strengths aligned to those recommended for ACMG/AMP classification codes. Altered mRNA splicing or function relative to known nonpathogenic variant controls were moderately to strongly predictive of variant pathogenicity. Variant absence in population datasets provided supporting evidence for variant pathogenicity. These findings have direct relevance for BRCA1 and BRCA2 variant evaluation, and justify the need for gene-specific calibration of evidence types used for variant classification

Large scale multifactorial likelihood quantitative analysis of BRCA1 and BRCA2 variants: An ENIGMA resource to support clinical variant classification

Abstract The multifactorial likelihood analysis method has demonstrated utility for quantitative assessment of variant pathogenicity for multiple cancer syndrome genes. Independent data types currently incorporated in the model for assessing BRCA1 and BRCA2 variants include clinically calibrated prior probability of pathogenicity based on variant location and bioinformatic prediction of variant effect, co-segregation, family cancer history profile, co-occurrence with a pathogenic variant in the same gene, breast tumor pathology, and case-control information. Research and clinical data for multifactorial likelihood analysis were collated for 1395 BRCA1/2 predominantly intronic and missense variants, enabling classification based on posterior probability of pathogenicity for 734 variants: 447 variants were classified as (likely) benign, and 94 as (likely) pathogenic; 248 classifications were new or considerably altered relative to ClinVar submissions. Classifications were compared to information not yet included in the likelihood model, and evidence strengths aligned to those recommended for ACMG/AMP classification codes. Altered mRNA splicing or function relative to known non-pathogenic variant controls were moderately to strongly predictive of variant pathogenicity. Variant absence in population datasets provided supporting evidence for variant pathogenicity. These findings have direct relevance for BRCA1 and BRCA2 variant evaluation, and justify the need for gene-specific calibration of evidence types used for variant classification. This article is protected by copyright. All rights reserved.Peer reviewe

A New Modeling Approach for the Adsorption Isotherm of Pure Components on Nonporous Surfaces

For the modeling of adsorption on the molecular level, density functional theory (DFT) is a suitable tool. Within the DFT different approaches (local (LDFT) or nonlocal (NLDFT)) can be applied, which differ in the numerical effort for the minimization of the grand thermodynamic potential to calculate the density profile of the confined fluid. We propose an alternative method combining the numerical advantages of the LDFT with the more realistic density profiles usually obtained with the NLDFT. The basic idea of the alternative consists of the incorporation of a square gradient term, known from density gradient theory, into the grand thermodynamic potential describing a confined fluid. The gradient term leads to the elimination of the unphysical jumps in the density profile at the liquid–gas phase transition and, consequently, to the elimination of the unphysical kinks in the adsorption isotherm. The new method was utilized to model the adsorption isotherms of nitrogen, methane, ethane, ethylene, and carbon dioxide on a nonporous carbon surface at different temperatures, where the fluid properties were described using the Perturbed Chain Polar–Statistical Associated Fluid Theory (PCP-SAFT). It was found that the influence parameter of the gradient term already known from the calculation of surface tension can not be transferred to the adsorption isotherm, because the value for the adsorption isotherm must be 1 order of magnitude smaller than for the calculation of the surface tension of the free fluid. The solid–fluid interaction energy depends slightly in a linear way on temperature. The obtained adsorption isotherms were compared to experimental data taken from the literature. The new model allows an excellent description of the adsorption isotherms of different fluids at low pressure, where only gas is present, and at high pressure, where only liquid is present. However, at pressures where the phase transition takes place, slight deviations occur