The concept of a near-field Raman probe

This article considers the possibility to use tips, which are functionalised by Raman active molecules, as new Raman probes for near-field optics in such a way that the Raman spectrum can be recorded of such a tip. If the Raman spectrum of the probe molecules is sensitive to their immediate environment, the probe can be used to map a surface by its local influence on the Raman spectrum of the probe. This new concept may be very promising for the investigation of specific interactions at the nanoscale by an optical response. Examples of the sensitivity of such a probe to the local environment are presented as a basis for further development of such a probe.     

Influence of the Temperature on Coccolith-Containing Systems from Emiliania huxleyi Cultivations

Thermogravimetric analysis of a coccolith-containing biogenic broth showed a three-step degradation process. According to this system behavior, the biogenic broth was heated to specific temperatures and characterized in terms of its morphology, surface chemistry, and crystallinity. The elemental and organic composition of the treated samples was also evaluated and compared to the reference material. The presented results were acquired in an effort to exploit pretreatment scenarios for such a biogenic system that would improve and support a separation process.     

Werkstoffliche Aufbereitung von Wärmedämmverbundsystemen

Due to increasing energy requirements for buildings, thermal insulation composite systems (TICS) have been used to insulate building facades since the 1970s. In view of the longevity of these composite materials, there has been an increased amount of TICS waste in recent years. Since there is no current recycling concept for these systems, an enormous resource efficiency potential remains unused. Due to the complexity of composite materials this study focuses on the pretreatment and discusses different processing steps in detail.     

Temperature-Dependent Re-alignment of the Short Multifunctional Peptide BP100 in Membranes Revealed by Solid-State NMR Spectroscopy and Molecular Dynamics Simulations

BP100 is a cationic undecamer peptide with antimicrobial and cell-penetrating activities. The orientation of this amphiphilic α-helix in lipid bilayers was examined under numerous conditions using solid-state ¹⁹F, ¹⁵N and ²H NMR. At high temperatures in saturated phosphatidylcholine lipids, BP100 lies flat on the membrane surface, as expected. Upon lowering the temperature towards the lipid phase transition, the helix is found to flip into an upright transmembrane orientation. In thin bilayers, this inserted state was stable at low peptide concentration, but thicker membranes required higher peptide concentrations. In the presence of lysolipids, the inserted state prevailed even at high temperature. Molecular dynamics simulations suggest that BP100 monomer insertion can be stabilized by snorkeling lysine side chains. These results demonstrate that even a very short helix like BP100 can span (and thereby penetrate through) a cellular membrane under suitable conditions.     

Aufbaukörnungen aus gipshaltigem Mauerwerkbruch – Teil 2: Untersuchungen im Pilotmaßstab

Heterogeneous construction waste such as masonry rubble has potential as a raw material for the production of lightweight aggregates similar to expanded clays or even pumice. In the present paper, the suitability of feedstocks with considerable gypsum contents was investigated in a pilot plant. Based on the results, initial technological statements could be made. According to these, energetic advantages can be expected in comparison with lightweight aggregates made from expanded clays.     

Combinatorial synthesis of new cationic lipids and high-throughput screening of their transfection properties

Here we describe the first synthesis-screening approach for the identification and optimization of new cationic lipids for gene transfer in various cell lines. Combinatorial solid-phase chemistry was used to synthesize a library of new cationic lipids based on 3-methylamino-1,2-dihydroxypropane as the polar, cationic lipid part. As the nonpolar lipid part, different hydrocarbon chains were bound to the amino group of the scaffold and the amino group was further methylated to afford constantly cationic lipids. Lipids were synthesized in both configurations and as racemates, and the counter ions were also varied. By using a fully automated transfection screening method and COS-7 cells, the cationic lipid N,N-ditetradecyl-N-methyl-amino-2,3-propanediol (KL-1-14) was identified as a candidate lipid for the development of an improved transfection reagent. Screening the transfection properties of KL-1-14 in numerous combinations with the helper lipids dioleoylphosphatidylethanolamine (DOPE) and cholesterol (Chol) revealed that Chol is the most suitable helper lipid and the best KL-1-14/Chol ratio is 0.5-0.7. Compared to the standard transfection lipid N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl sulfate (DOTAP), transfection efficiency was improved by a factor of about 40. Furthermore, by using R- and S-configured KL-1-14, it could be shown that the configuration of the lipids had no significant influence on its transfection efficiency. The highest transfection efficiencies were achieved with chloride as the counter ion. The new lipofection reagent was further tested to transfect the cell lines MDA-MB-468, MCF-7, MDCK-C7, and primary dentritic cells (DC), which are important for the development of new anticancer gene therapy strategies. Even in these cells, KL-1-14/Chol (1:0.6) had improved transfection efficiencies, which were about two to four times higher than for DOTAP.     

NMR Study on the Acidity of TS-1 Zeolite

The acidic properties of TS-1 and Silicalite-1 zeolites have been investigated by the solid-state MAS NMR technique capable of in situ sample pretreatment. As shown by a combination of the ³¹P MAS NMR and ¹H MAS NMR techniques with trimethylphosphine, not only Brønsted acid sites but also Lewis acid sites exist in the TS-1 zeolites. Moreover, TS-1 zeolite is more acidic compared with Silicalite-1. The ¹H, ²⁹Si MAS NMR spectra and the resonance related to Brønsted acid species in the ³¹P MAS NMR spectra demonstrate clearly that the presence of titanium in the framework results in the formation of a new hydroxy group, titanols, which is more acidic than silanols of Silicalite-1. The ³¹P MAS NMR measurements also illustrate convincingly the existence of at least two different Lewis acid species on the TS-1 zeolites. The conversion of propylene oxide into methoxypropanol catalyzed by TS-1 or Silicalite-1 zeolite in methanol solution as a test reaction has also been described. With the increase of titanium in zeolite, TS-1 appears to have a higher activity during the reaction of propylene oxide to methoxypropanol.     

产品最优化:信息是关键

随着技术的进步和信息的日益全球共享化,生产DVD已经变得不再神秘。今天的DVD生产线已经达到了一个相当可靠的程度,凭借这种成熟和可靠的标准,任何制造商均可以向市场提供令人满意的足够数量的DVD产品。最近的技术发展更吸引了大批的新来者纷纷加入复制领域,同时这也为DVD走向大规模生产铺平了道路。当人们攻克了DVD的播放性问题之后,整个DVD行业的焦点目前正在转向另外一个不同的领域:如何在保持生产成本尽可能低的情况下充分满足稳步增长的市场对高质量DVD的需求? 对于这一问题,显而易见的答案就是使生产     

Synthese und charakterisierung von butadien-divinylbenzol-copolymeren

The copolymerization of butadiene with a technical divinylbenzene fraction was investigated to study the modification of cis-1,4 polybutadiene. Beside the Ziegler-Natta-catalyst nickeloctanoate/bortrifluoride/aluminiumtriethyl, another catalytic system consisting of nickeloctanoate/titaniumtetrachloride/aluminiumtriethyl was used, which allows to polymerize more divinylbenzene because of its higher activity toward vinylaromates. With the help of spectroscopical, pyrolysis-gaschromatographical and thermoanalytical methods one can obtain relations between glass-, crystallization- and melting temperature and the microstructure of the polymer. It can be shown that not only the divinylbenzene but also the trans-1,4- and the 1,2-vinyl units are statistically distributed in the polymer. By this, beside the pyrolysis-gaschromatography, particularly the differential scanning calorimetry is a useful tool to characterize the structure of partially crosslinked polymers obtained from polymerization of technical fractions.