Improvement of utero-placental perfusion by transcutaneous nerve stimulation (author's transl)

A report is given on 37 patients with a diminished utero-placental perfusion. 12 patients underwent only once, 25 patients daily over 2 to 3 weeks a transcutaneous lumbo-sacral electric nerve stimulation. Both, the 12 patients stimulated only once and the 25 patients with daily stimulation, showed a significant increase of utero-placental perfusion measured by the method of radioisotope placental perfusion. Transcutaneous nerve stimulation (TNS) therefore could be used for therapeutic purpose in cases of placental dysfunction.     

欧洲和德国的钢铁工业的环保现状和发展(二)

(上接2004年第3期) 3环境保护的组织 在环境保护的领域中,已经达到了完成给定的一个很复杂的任务的水平,只有通过综合的技术和复杂手段来取得进一步的成功.Rio and约翰内斯堡会议的觉醒,特别是可持续发展的要求,及组织的工具的快速发展.环境保护领域中的技术可以通过以下手段日益完善:     

On the influence of baseline startle reactivity on the indexation of prepulse inhibition.

Prepulse inhibition (PPI) of the startle reflex refers to the reduction of the reflexive startle response to an intense pulse stimulus when its presentation is shortly preceded by a weak prepulse stimulus. PPI is considered as a cross-species translational model of sensorimotor gating, and deficient PPI has been reported in a number of neuropsychiatric disorders. Although a part of the literature is based on the assumption that PPI is independent of the baseline startle reaction, there is accumulating evidence (Csomor et al., 2006; Sandner & Canal, 2007; Yee, Chang, Pietropaolo, & Feldon, 2005) that argues against such an independency. The authors systematically investigated whether PPI indexed as percentage or difference score is dependent on the magnitude of baseline startle reactivity in healthy human volunteers and in C57BL/6 mice. The results revealed that both indexations of PPI were affected by the magnitude of the baseline startle. The authors highlight the pitfalls of different methods to index PPI, especially when startle reactivity differs considerably between groups under comparison, and offer practical recommendations to satisfactorily deal with such baseline differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diindenoperylene derivatives: A model to investigate the path from molecular structure via morphology to solar cell performance

Efficient organic electronic devices require a detailed understanding of the relation between molecular structure, thin film growth, and device performance, which is only partially understood at present. Here, we show that small changes in molecular structure of a donor absorber material lead to significant changes in the intermolecular arrangement within organic solar cells. For this purpose, phenyl rings and propyl side chains are fused to the diindenoperylene (DIP) molecule. Grazing incidence X-ray diffraction and variable angle spectroscopic ellipsometry turned out to be a powerful combination to gain detailed information about the thin film growth. Planar and bulk heterojunction solar cells with C60 as acceptor and the DIP derivatives as donor are fabricated to investigate the influence of film morphology on the device performance. Due to its planar structure, DIP is found to be highly crystalline in pristine and DIP:C60 blend films while its derivatives grow liquid-like crystalline. This indicates that the molecular arrangement is strongly disturbed by the steric hindrance induced by the phenyl rings. The high fill factor (FF) of more than 75% in planar heterojunction solar cells of the DIP derivatives indicates excellent charge transport in the pristine liquid-like crystalline absorber layers. However, bulk heterojunctions of these materials surprisingly result in a low FF of only 54% caused by a weak phase separation and thus poor charge carrier percolation paths due to the lower ordered thin film growth. In contrast, crystalline DIP:C60 heterojunctions lead to high FF of up to 65% as the crystalline growth induces better percolation for the charge carriers. However, the major drawback of this crystalline growth mode is the nearly upright standing orientation of the DIP molecules in both pristine and blend films. This arrangement results in low absorption and thus a photocurrent which is significantly lower than in the DIP derivative devices, where the liquid-like crystalline growth leads to a more horizontal molecular alignment. Our results underline the complexity of the molecular structure-device performance relation in organic semiconductor devices.     

GC-IMS and machine learning for the rapid differentiation of complex isomeric mixtures of terpenes

Zinc is an essential trace element (TE). Insufficient supply can lead to severe health effects. According to current estimations, about 20% of the world's population are at risk of an insufficient zinc supply. Thereby geographic differences occur. In developing countries and emerging countries the population is at substantially higher risk of zinc deficiency, compared to industrial countries. In the latter, mostly people from specific population groups are at risk. Among them are elderly people, as studies have shown a decrease in the total zinc concentration of the serum with increasing age. To treat zinc deficiency, it hast to be diagnosed first. Biomarkers established so far are well suited to evaluate the zinc status of populations. However, they have their limitations when it comes to individuals. A good biomarker for this application area is still missing. In this context, the serum free zinc concentration has been suggested as a possible biomarker for the zinc status of individuals. The term free zinc describes the zinc pool that is loosely bound to low molecular weight fractions. Data in the literature implictates that free zinc represents the zinc that is biologically active and available for interaction with cells. Hence, the serum free zinc concentration might be a better parameter to reflect an individual's zinc status than the total zinc concentration. Therefore, in the present work a fluorescent-probe based assay was established for determining the free zinc concentration in human and murine serum samples. The determined free zinc concentrations of the analyzed serum samples were in the nanomolar range. The free and total zinc concentrations in the sera of the different sample-groups analyzed either showed no linear correlation or a weak linear correlation. In several sample-groups analyzed, the free zinc concentration in sera from females was significantly lower than in sera from males. The data obtained support the meaning of the serum free zinc concentration as an independent parameter besides the total zinc concentration. However, based on the current data it cannot be evaluated yet, if the free zinc concentration in serum is a well-suited biomarker for an individual's zinc status. Still it seems promising to further investigate this parameter, with regard to its suitability as a biomarker as well as its physiological relevance. In the context of the present work, samples from a feeding study with mice were analyzed. The aim of the study was to investigate the influence of TE-supply on age-related alterations in TE-homeostasis and TE-dependent physiological processes. Adult and old mice were treated with a TE-supply either adequate, suboptimal in several TEs (zinc, selenium, copper, iron) simultaneously or age-adjusted. The latter had an elevated content of zinc and selenium and aimed to investigate, whether age-related alterations can be prevented by an elevated supply of TEs, whose serum concentration decreases with increasing age. As a central organ of the body's zinc-homeostasis, the liver was examined. For this, a fluorescent-probe based assay was established for determining the free zinc concentration in homogenized murine liver tissue. A tendency of the free zinc concentration in the liver tissue to reflect the zinc-supply of the mice was shown. In addition, the free zinc concentration in liver tissue samples from female mice was significantly higher than in samples from male mice. The total zinc content of the liver tissue showed no such effects of zinc supply or sex. The age of the mice did not affect the free zinc concentration of the liver tissue. The functionality of the immune system is dependent on zinc, in addition shows age-related alteration. Therefore, as part of the immune system, isolated splenocytes were examined. The percentage of B-cells, T-helper cells, cytotoxic T-cells, macrophages and dendritic cells was determined, as well as the respective cellular free zinc concentration and the relative content of several pro- and anti-inflammatory cytokines (interleukin (IL)-2, IL-10, IL-17, interferon-γ and tumor necrosis factor α) in the supernatant after stimulation with phytohaemagglutinin (PHA). A decrease in the percentage of T-helper cells, an increase in percentage of dendritic cells, a decrease in the cellular free zinc concentration of B-cells and dendritic cells as well as an increase in relative IL-10 content in the supernatant after stimulation with PHA was shown in relation to age. The age-adjusted TE-supply showed no effect on these age-related alterations of the immune system. This implicates that the underlying mechanisms are not modulated by an enhanced nutritional supply of zinc and selenium.     

Equilibrium sampling through membranes of freely dissolved copper concentrations with selective hollow fiber membranes and the spectrophotometric detection of a metal stripping agent

A sensitive spectrophotometric method for the determination of freely dissolved copper concentrations in aqueous samples after preconcentration with hollow fiber membrane extraction has been developed. The method is based on the equilibrium sampling through a selective membrane into an acceptor solution containing 4-(pyridyl-2-azo)resorcinol (PAR), which serves as stripping agent and metal indicator. Negligible extraction of interferences and equilibrium enrichment of copper allowed for selective spectrophotometric determination of the Cu-PAR complex. Some important extraction parameters such as acceptor composition, shaking, equilibrium time, and sample volume were studied. The optimized methodology showed good linearity in the range of 5-100 microg/L, an enrichment factor of 93, good repeatability and reproducibility (RSDs < 6%, n = 6), and a detection limit of 4 microg/L. The cationic metals Ni2+, C(2+, Cd2+, Fe3+, Pb2+, Zn2+, and Mn2+ were shown not to interfere with the measurement of Cu2+. Measurements on samples containing mixtures of various ligands and cations were in good agreement with theoretically calculated concentrations, and the method was also applied to environmental samples. The developed technique requires less labor and less sophisticated equipment than conventional methods typically based on atomic absorption spectrometry or ICP.     

13C- and 23Na-NMR investigations on alkali cellulose

Summary Solid state ²³Na- and ¹³C-NMR spectra of alkali cellulose are presented as a function of NaOH-concentration of the steeping lye, steeping temperature and amount of adhering lye (press factor). Results are discussed with regard to chemical binding of NaOH to the cellulose chain in the system cellulose/ NaOH/H₂O.Presented at the 22nd Microsymposium, Characterization of Structure and Dynamics of Macromolecular Systems by NMR Methods, Prague, CSSR, July 20–23,1981     

引领电容触控应用热潮 浅谈QMatrix技术

触控技术在家电,消费性电子产品及移动电子产品中,已逐渐取代电子机械式开关.它们之所以普及的动力,是因为设计人员认为触控技术能让他们创造风格独特及功能良好的设计,在产品差异化的同时,也能为终端使用者创造更高的价值.