Surface modification of macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) resins for improved Candida antarctica lipase B immobilization

Crosslinked macroporous hydrophilic poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) [abbreviated poly(GMA-co-EGDMA)] with identical chemical structure (60% of glycidyl methacrylate) but with varied average pore sizes (from 30 to 560 nm), specific surface areas (from 13.2 to 106.0 m²/g), specific volumes (from 0.755 to 1.191 cm³/g) and particle sizes (<100 μm–630 μm) were synthesized via suspension polymerization. Modifications of poly(GMA-co-EGDMA) with various diamines (1,2-diaminoethane, 1,4-diaminobutane, 1,6-diaminohexane and 1,8-diaminooctane), 2-fluoroethylamine, glutaraldehyde and cyanuric chloride were carried out. The influence of the interaction between Candida antarctica lipase B (Cal-B) and various carriers during immobilization on the loading and hydrolytic activity (hydrolysis of para-nitrophenyl acetate) of the immobilized Cal-B were studied. Immobilization of Cal-B was performed at different temperatures and pH values. Cal-B immobilized at 30 °C and pH 6.8 was leading to increased activities. Purely physical adsorption between enzyme and copolymer was observed on carriers in which amine or fluorine groups were introduced into the carrier structure by modification with various diamines or 2-fluoroethylamine. As a consequence enzyme loading and activity decreases. In contrary, modification of the poly(GMA-co-EGDMA) with glutaraldehyde and cyanuric chloride results in a covalent connection between enzyme and carrier. The obtained results show a significant increase in Cal-B activity. The influence of the amount of glutaraldehyde and cyanuric chloride used for modification was screened. Increasing the amount of glutaraldehyde or cyanuric chloride used for modification resulted in an increase of the enzyme loading. Consequently, higher amount of glutaraldehyde used led to a higher fraction of the enzyme molecules that are covalently connected on to the carrier. As the amount of glutaraldehyde or cyanuric chloride used for modifications increases, activity of immobilized C. antarctica lipase B primarily increases, showing the highest value for 0.66% and 0.050% w/w, respectively, and subsequently decreases. We could show that Cal-B immobilized on epoxy-containing copolymer modified with glutaraldehyde and cyanuric chloride performs higher activity than free enzyme powder.     

Cleanability of Surfaces from Active Pharmaceutical Ingredient Surrogate Riboflavin by Falling Film

Falling films in wash down process are of major interest for pharmaceutical isolators, which are used for processing of highly potent pharmaceutical products. In this study multiple process parameters were examined with common materials of isolator systems. The importance of material and surface finish in respect of cleanability and complete wetting as well as a combination of process parameters are presented and discussed. For cleaning validation an effect of high interest was discovered: swab sampling areas changed their properties over many repeated cycles and showed decreased cleanability.     

Befugnisse der Aufsichtsbehörde gegenüber Rechtsanwälten

Der Beschluss des KG Berlin hat gro?e Beachtung in der Anwaltschaft gefunden. Die Entscheidung ist damit Gegenstand vieler zustimmender Bewertungen. Die folgenden Ausführungen sollen einerseits die Fehler der Entscheidung aufzeigen und andererseits einen Gegenpol zu diesen Auseinandersetzungen darstellen.     

Silicon‐Doped LiFePO4 Single Crystals: Growth,Conductivity Behavior,and Diffusivity

Single crystals of silicon doped LiFePO₄ with a silicon content of 1% are grown successfully by the floating zone technique and characterized by single‐crystal and powder X‐ray diffraction, secondary ion mass spectroscopy, and chemical analysis. Electron paramagnetic resonance demonstrates the presence of only Fe²⁺; no traces of Fe³⁺ are found. Impedance spectroscopy as well as step‐function polarization/depolarization (DC) measurements are carried out using the cells Ti/LiFe(Si)PO₄/Ti and LiAl/LiI/LiFe(Si)PO₄/LiI/LiAl. The electronic and ionic conductivities as well as the Li‐diffusivity of the sample in the major crystallographic directions ([h00], [0k0], and [00l]) are determined. Within experimental error the transport properties along the b‐ and c‐axes are found to be the same but differ significantly from the a‐axis, which exhibits lower values. Compared to undoped LiFePO₄, Si‐doping leads to an increase of the ionic conductivity while the electronic conductivity decreases, which is in agreement with a donor effect. The activation energies of conductivities and diffusivities are interpreted in terms of defect chemistry and relevant Brouwer diagrams are given.     

The effect of the particle size and the morphology of alumina powders on the processing of green bodies by electrophoretic deposition

The electrophoretic deposition (EPD) method was investigated for the preparation of compacts from nanosized alumina powders. Ethanol suspensions of commercially available nanosized transition alumina and α-alumina powders were used. In addition, submicron powders were also considered for comparison. Besides the influence of operational pH change, the influence of the addition of three different surfactants – two branched polyethylene imines with molecular masses 1800 and 10,000, and citric acid—on the zeta-potential of the particles in ethanol and afterwards on the EPD was investigated.The packing density of the green parts prepared by the EPD of nanosized α-alumina powders at 30 V/cm was low (the green density was 27 vol. % of the theoretical density—TD), and a bimodal pore size distribution was observed. In contrast, the packing density in deposits made with the transition alumina nanopowder was much higher (the green density was 42 vol. % of the TD) and a monomodal distribution of pores was observed. In general, for all the deposits made from nanosized alumina powders, the particle-packing density was found to be lower than for those made from the submicron alumina powders (a green density equal to 59 vol. % of the TD).     

Policies and measures to address climate change in Central and Eastern European Countries

Pursuant to the commitments under the Framework Convention of Climate Change (FCCC), all Annex I Parties of FCCC have compiled their National Communications on Climate Change. There, Parties have reported the national greenhouse gas inventories, policies, and measures to address climate change, the greenhouse gas emissions projections, vulnerability and adaptation to climate change, and education and public awareness.

Implementation of policies and measures to address climate change in economies in transition (EIT) is very complicated due to the experienced deep economic crisis. It is important to outline the efforts of EIT countries to identify their climate change policy and to recognize the most effective policies and measures achieved under these countries' special circumstances.

This paper compiles information from the policies and measures section of the National Communications of nine EIT countries. The analysis has been carried out in the framework of overall policy context and the national circumstances of EIT countries in terms of energy and economy development.

In general, policies and measures in EIT countries tend to follow the trends observed in the other Annex I Parties to the FCCC. They address primarily carbon dioxide from fossil fuel combustion as the most important greenhouse gas and the energy transformation sector as the major greenhouse emissions source. The most effective mitigation measures — in terms of both greenhouse gas emission reduction and costs — were energy efficiency and the promotion of non-fossil energy sources. A prevailing part of policies and measures implemented or under implementation in EIT countries were cost-effective and no-regret measures. It was considered very difficult in these countries to go beyond no-regret measures in a situation of deep economic crisis and insufficient investments.     

Managing one’s identities in organisational and social settings

Interacting in the Internet, users should be empowered to use only those subsets of their personal attributes, called partial identities, which are appropriate for the actual situation and context. Refraining from acting under few and easily linkable partial identities is a prerequisite for trustworthy privacy. Traditionally user-controlled identity management systems primarily support individuals interacting with organisations, but mainly ignore special needs which arise if individuals interact with each other. To support online communities those systems have to change. From TU Dresden: Prof. Dr. Andreas Pfitzmann, head of the privacy and security group, and the research assistants Dipl.-Inform. Katrin Borcea-Pfitzmann, Dipl. Medien-inf. Katja Liesebach and Dipl.-Inform. Sandra Steinbrecher. From ULD, Kiel: Dipl.-Inform. Marit Hansen, head of PET division. Research Focus: Privacy in Identity Management and Application Design This work was funded in part by the PRIME project which receives research funding from the European Union’s Sixth Framework Programme and the Swiss Federal Office for Education and Science.     

Amino‐polyvinyl Alcohol Coated Superparamagnetic Iron Oxide Nanoparticles are Suitable for Monitoring of Human Mesenchymal Stromal Cells In Vivo

Mesenchymal stromal cells (MSCs) are promising candidates in regenerative cell‐therapies. However, optimizing their number and route of delivery remains a critical issue, which can be addressed by monitoring the MSCs’ bio‐distribution in vivo using super‐paramagnetic iron‐oxide nanoparticles (SPIONs). In this study, amino‐polyvinyl alcohol coated (A‐PVA) SPIONs are introduced for cell‐labeling and visualization by magnetic resonance imaging (MRI) of human MSCs. Size and surface charge of A‐PVA‐SPIONs differ depending on their solvent. Under MSC‐labeling conditions, A‐PVA‐SPIONs have a hydrodynamic diameter of 42 ± 2 nm and a negative Zeta potential of 25 ± 5 mV, which enable efficient internalization by MSCs without the need to use transfection agents. Transmission X‐ray microscopy localizes A‐PVA‐SPIONs in intracellular vesicles and as cytosolic single particles. After identifying non‐interfering cell‐assays and determining the delivered and cellular dose, in addition to the administered dose, A‐PVA‐SPIONs are found to be non‐toxic to MSCs and non‐destructive towards their multi‐lineage differentiation potential. Surprisingly, MSC migration is increased. In MRI, A‐PVA‐SPION‐labeled MSCs are successfully visualized in vitro and in vivo. In conclusion, A‐PVA‐SPIONs have no unfavorable influences on MSCs, although it becomes evident how sensitive their functional behavior is towards SPION‐labeling. And A‐PVA‐SPIONs allow MSC‐monitoring in vivo.