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91.
92.
G. Lehmann Barbara Binkle Heike Faller 《European Journal of Lipid Science and Technology》1984,86(7):286-288
Isolation and Identification of Dyes in Soaps A method is described for isolation and identification of dyes in soaps. The principle depends on separation of the dyes with the help of various organic solvents or acids, adsorption on polyamide powder and identification through thin layer chromatography. The inorganic pigments are identified by classical analytical procedures. 相似文献
93.
Heike Laqua Torsten Bluhm Peter Heimann Christine Hennig Hugo Kroiss Jon G. Krom Georg Kühner Marc Lewerentz Josef Maier Jörg Schacht Anett Spring Andreas Werner Manfred Zilker 《Fusion Engineering and Design》2012,87(12):1958-1960
ITER, Wendelstein 7-X, LHD, and TORE SUPRA are experimental facilities designed to lead the way to steady state fusion devices. These experiments require strategies to sustain a discharge in case of unforeseen events, e.g. heat overloads of plasma facing components or the failure of a plasma heating source. A recovery strategy is needed to get the discharge back for physics exploitation. For this purpose the W7-X segment control framework provides means for automated event detection along with options to formulate and initiate a recovery strategy. Besides handling of failures and degradation there are events that represent a desired plasma physical effect. An example for this kind of event is a transition to from Low to High-Confinement mode. These events indicate that a certain plasma state is reached and scientific examination can be altered thus enabling event-driven multiple experiments per discharge. Examples of both kinds of events will be presented and compared to other approaches in the community. 相似文献
94.
Heike Kitzig-Frank Taghi Tawakoli Bahman Azarhoushang 《The International Journal of Advanced Manufacturing Technology》2017,91(9-12):2949-2962
Alumina is an advanced ceramic that is frequently used in high-performance applications. Grinding of alumina is usually associated with micro-cracks and deteriorated surface quality. Ultrasonic-assisted grinding has been introduced in several applications as a promising method to overcome these constraints. In order to get a deeper knowledge of the characteristics of material removal mechanisms in alumina during grinding with ultrasonic stimulation of the workpiece, single-grain scratch tests were performed and the theoretical and experimental kinematics of grain-workpiece engagement were investigated. It was shown that in the real contact conditions, interrupted contact conditions happen, which is analogous to the theoretical model. The measured workpiece resonance frequency and mode shape were very close to the design conditions. The investigations show that the superposition of ultrasonic vibration into the grinding process increases the material removal of each grain. This result fully correlates with the presented theoretical analysis. Additionally, it was found that the impact action of ultrasonic-assisted grinding induces chipping around the produced scratch. 相似文献
95.
Heike Gerhardt Oliver Betz Klaus Albert Michael Lämmerhofer 《Journal of chemical ecology》2016,42(8):725-738
Spatially controlled in vivo sampling by contact solid phase microextraction with a non-coated silica fiber combined with gas chromatography-mass spectrometry (GC-MS) was utilized for hydrocarbon profiling in tarsal adhesion secretions of four insect species (Nicrophorus vespilloides, Nicrophorus nepalensis, Sagra femorata, and Gromphadorhina portentosa) by using distinct adhesion systems, viz. hairy or smooth tarsi. For comparison, corresponding samples from tibiae, representing the general cuticular hydrocarbon profile, were analyzed to enable the statistical inference of active molecular adhesion principles in tarsal secretions possibly contributed by specific hydrocarbons. n-Alkanes, monomethyl and dimethyl alkanes, alkenes, alkadienes, and one aldehyde were detected. Multivariate statistical analysis (principal component and orthogonal partial least square discriminant analyses) gave insights into distinctive molecular features among the various insect species and between tarsus and tibia samples. In general, corresponding hydrocarbon profiles in tarsus and tibia samples largely resembled each other, both qualitatively and in relative abundances as well. However, several specific hydrocarbons showed significantly different relative abundances between corresponding tarsus and tibia samples, thus indicating that such differences of specific hydrocarbons in the complex mixtures might constitute a delicate mechanism for fine-tuning the reversible attachment performances in tarsal adhesive fluids that are composed of substances originating from the same pool as cuticular hydrocarbons. Caused by melting point depression, the multicomponent tarsal adhesion secretion, made up of straight chain alkanes, methyl alkanes, and alkenes will have a semi-solid, grease-like consistency, which might provide the basis for a good reversible attachment performance. 相似文献
96.
Ass. Prof. Tien Dinh Vu Associate Prof. Rangabhashiyam Selvasembian Dr.-Ing. Ivana Mutavdžin Dr.-Ing. Elena Horosanskaia Prof. Heike Lorenz Prof. Andreas Seidel-Morgenstern 《化学,工程师,技术》2023,95(11):1851-1857
The flavonoid rutin is present in significant amounts in the flower buds of Sophora japonica L. It offers numerous desired pharmacological effects. Under certain extraction conditions quercetin is found as a hydrolysis product which needs to be separated from rutin. This paper describes the application of liquid chromatography to solve this task. Based on the determination of adsorption equilibrium constants and column efficiencies, the productivity of the separation process is estimated, and scale-up considerations are presented. A comparison with alternatively directly crystallizing rutin from raw extracts is also reported. 相似文献
97.
Cristina Asensio-Jimenez Leszek Niewolak Heike Hattendorf Bernd Kuhn Pawel Huczkowski Lorenz Singheiser Willem Joseph Quadakkers 《Oxidation of Metals》2013,79(1-2):15-28
Previous studies revealed that initial sample thickness affects the growth rate of oxide scales formed during 800 or 900 °C air exposure. The effect is partially related to differences in depletion of minor alloying additions such as Mn, Ti, La in thick and thin specimens. However, it has previously been proposed that the specimen thickness dependence is partially governed by differences in creep strength of thick and thin substrates. To investigate this hypothesis, discontinuous air oxidation experiments were carried out with the Laves phase strengthened ferritic steel Crofer 22 H at 800 °C. Comparing the data for solution annealed and pre-aged (500 h, 900 °C) materials it could be shown that intrinsic creep strength of the alloy substantially affects oxidation rates. The observations can qualitatively be explained by assuming the relaxation of oxide growth stresses by plastic deformation of the metallic substrate to be an important parameter affecting the kinetics of oxide scale growth. 相似文献
98.
Quantitative characterization of degradation processes in situ by means of a bioreactor coupled flow chamber under physiological conditions using time‐lapse SRµCT 下载免费PDF全文
99.
Jeremy Tsung-Chieh Chen Lea Schmidt Christina Schürger Mohammed K. Hankir Susanne M. Krug Heike L. Rittner 《International journal of molecular sciences》2021,22(18)
The blood–nerve barrier and myelin barrier normally shield peripheral nerves from potentially harmful insults. They are broken down during nerve injury, which contributes to neuronal damage. Netrin-1 is a neuronal guidance protein with various established functions in the peripheral and central nervous systems; however, its role in regulating barrier integrity and pain processing after nerve injury is poorly understood. Here, we show that chronic constriction injury (CCI) in Wistar rats reduced netrin-1 protein and the netrin-1 receptor neogenin-1 (Neo1) in the sciatic nerve. Replacement of netrin-1 via systemic or local administration of the recombinant protein rescued injury-induced nociceptive hypersensitivity. This was prevented by siRNA-mediated knockdown of Neo1 in the sciatic nerve. Mechanistically, netrin-1 restored endothelial and myelin, but not perineural, barrier function as measured by fluorescent dye or fibrinogen penetration. Netrin-1 also reversed the decline in the tight junction proteins claudin-5 and claudin-19 in the sciatic nerve caused by CCI. Our findings emphasize the role of the endothelial and myelin barriers in pain processing after nerve damage and reveal that exogenous netrin-1 restores their function to mitigate CCI-induced hypersensitivity via Neo1. The netrin-1-neogenin-1 signaling pathway may thus represent a multi-target barrier protector for the treatment of neuropathic pain. 相似文献
100.
Karla Johanna Ruth Hoyer-Allo Martin Richard Spth Ruth Hanssen Marc Johnsen Susanne Brodesser Kathrin Kaufmann Katharina Kiefer Felix Carlo Koehler Heike Gbel Torsten Kubacki Franziska Grundmann Bernhard Schermer Jens Brüning Thomas Benzing Volker Burst Roman-Ulrich Müller 《International journal of molecular sciences》2021,22(11)
Acute kidney injury (AKI) is a frequent and critical complication in the clinical setting. In rodents, AKI can be effectively prevented through caloric restriction (CR), which has also been shown to increase lifespan in many species. In Caenorhabditis elegans (C. elegans), longevity studies revealed that a marked CR-induced reduction of endocannabinoids may be a key mechanism. Thus, we hypothesized that regulation of endocannabinoids, particularly arachidonoyl ethanolamide (AEA), might also play a role in CR-mediated protection from renal ischemia-reperfusion injury (IRI) in mammals including humans. In male C57Bl6J mice, CR significantly reduced renal IRI and led to a significant decrease of AEA. Supplementation of AEA to near-normal serum concentrations by repetitive intraperitoneal administration in CR mice, however, did not abrogate the protective effect of CR. We also analyzed serum samples taken before and after CR from patients of three different pilot trials of dietary interventions. In contrast to mice and C. elegans, we detected an increase of AEA. We conclude that endocannabinoid levels in mice are modulated by CR, but CR-mediated renal protection does not depend on this effect. Moreover, our results indicate that modulation of endocannabinoids by CR in humans may differ fundamentally from the effects in animal models. 相似文献