Recrystallization kinetics of ultrafine-grained Ni studied by dilatometry

The release of excess volume upon recrystallization of ultrafine-grained Ni deformed by high-pressure torsion was measured with a high-precision difference-dilatometer employing constant heating rates in the range from 0.3 to 10 K min^?1. The kinetics of the recrystallization process was analyzed according to the Johnson–Mehl–Avrami–Kolmogorov theory adapted to the case of constant heating rates. An effective Avrami exponent of 2 and a value of 1.20 eV for the activation energy of recrystallization was determined. Analysis by the Kissinger method yielded the same result for the activation energy.     

Mikrostruktur und Eigenschaften lichtbogengespritzter Schichten auf Eisenbasis

Microstructure and properties of Fe‐based wire arc sprayed coatings Innovative iron based feedstocks for wire arc spraying are a promising alternative for conventional carbide reinforced feedstocks for wear applications. Recently the main area of research is focused on improving the properties of deposited functional coatings by varying the wire composition. The influence on the crystalline structure and the dimension of the hard phases in the resulting microstructure is of particular interest in this context. The objective of the investigation is to produce coatings with an amorphous phase, submicron and nanocrystalline structure. The forming of the amorphous phase is influenced by high cooling rates of the molten and partly molten particles impinging on the substrate. Thus, the achieved coatings are characterized by high hardness as well as high corrosion and wear resistance. The present paper introduces iron based coatings produced by wire arc spraying. Due to the application of cored wires with a modified alloy composition the forming of an amorphous phase as well as a submicron‐ and nanocrystalline structure is promoted. The filling of the cored wires are based on FeB with a eutectic composition and is varied by adding Cr₃C₂, FeSi, FeCrC and AlMg. The adding of further elements like Cr, C, Si, Al and Mg should improve the forming of the amorphous phase. The deposited coatings are analyzed regarding to the resulting coating properties and phase composition in connection with the composition of the cored wires. XRD‐analysis’ proved that the Fe‐based coatings contain an amorphous phase.     

Review of Technology as symptom and dream.

Reviews the book, Technology as symptom and dream by Robert D. Romanyshyn (see record 1990-97140-000). This book is an empassioned call to reexamine the history of technology and to remember the desire that propelled it. Faced with the atom bomb and space flight, we can no longer ignore, Romanyshyn argues, the possibility of the final destruction of our planet. True to his vocation as a psychologist, Romanyshyn finds that the path toward preventing the suicide of mankind lies in re-examining, reflecting and retelling the story of our past and in understanding how it shapes our present and our future. He offers us a shift in perspective: maybe we have misunderstood what technology is all about. "Perhaps technology has been part of the earth's long history of coming to know itself, and perhaps in that effort we have been its servant. (...) On a dry African plain, in the silence of the early morning, one can still imagine technology as vocation, as the earth's call to become its agent and instrument of awakening. But in the shadows imagination falters and technology seems less the earth's way of coming to know itself and more the earth's way of coming to cleanse itself of us" (p. 3). Romanyshyn's book is biased, but biased in a positive way: he refuses the detached view of the uninvolved observer. The book speaks with passionate insight for the abandoned body and the repressed soul. Informed by the phenomenological critique of the scientific attitude, Romanyshyn attempts to recover the cultural history of consciousness and the lived body. He weaves a fascinating story that resonates with profound echoes from the past. He challenges the reader's presuppositions and our habitual modern ways of conceptualizing space, body and self. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rekristallisation von Eisen mit 6% Ni

Rekristallisation einer Eisenlegierung mit rd. 6% Ni bei Temperaturen zwischen 450 und 700°C nach Umwandlung in der Martensitstufe sowie Umwandlung in der Martensitstufe und 90% Kaltverformung. Verfolgung der Rekristallisation mit dem Mikroskop an korngremen- oder kornflächengeätzten Proben. Deutung der Temperaturabhängigkeit der Rekristallisation kaltverformter und nicht kaltverformter Proben.     

Nitroreductase-Mediated Release of Inhibitors of Lysine-Specific Demethylase 1 (LSD1) from Prodrugs in Transfected Acute Myeloid Leukaemia Cells

Lysine-specific demethylase 1 (LSD1) has evolved as a promising therapeutic target for cancer treatment, especially in acute myeloid leukaemia (AML). To approach the challenge of site-specific LSD1 inhibition, we developed an enzyme-prodrug system with the bacterial nitroreductase NfsB (NTR) that was expressed in the virally transfected AML cell line THP1-NTR⁺. The cellular activity of the NTR was proven with a new luminescent NTR probe. We synthesised a diverse set of nitroaromatic prodrugs that by design do not affect LSD1 and are reduced by the NTR to release an active LSD1 inhibitor. The emerging side products were differentially analysed using negative controls, thereby revealing cytotoxic effects. The 2-nitroimidazolyl prodrug of a potent LSD1 inhibitor emerged as one of the best prodrug candidates with a pronounced selectivity window between wild-type and transfected THP1 cells. Our prodrugs are selectively activated and release the LSD1 inhibitor locally, proving their suitability for future targeting approaches.     

Metabolism of quercetin and rutin by the pig caecal microflora prepared by freeze-preservation

Several studies confirm a protection of cardiovascular diseases and certain forms of cancer by dietary flavonoid intake. The bioavailability of flavonoids is influenced by the metabolism of the microflora in the intestine. Using a new in vitro model system the deglycosylation of the flavonol rutin and the degradation of its aglycone quercetin were investigated by using fresh pig caecal inocula in comparison to inocula prepared before by freeze-preservation between 6 wk and 5 months. The incubation experiments led to the same pattern of phenolic degradation products in comparable amounts in both preparations using HPLC-DAD and GC-flame ionization detection (GC-FID) or GC-MS detection within 24-48 h of incubation. With the preservation of the microbial vitality and the metabolic efficiency by freeze-preparation over several months the experimental design of microbial metabolism studies will be independent in time and locality.     

Non-starch polysaccharides from sunflower (Helianthus annuus) meal and palm kernel (Elaeis guineenis) meal—preparation of cell wall material and extraction of polysaccharide fractions

Two different chemical methods, sequential extraction with alkali and sodium chlorite and treatment with 4-methylmorpholine N-oxide (MMNO), were applied to the extraction of non-starch polysaccharides (NSP) from the enzymically deproteinated, water-insoluble cell wall materials of sunflower (Helianthus annuus L) meal and palm kernel (Elaeis guineensis Jacq) meal. The NSP content accounted for 550 g kg^?1 (sunflower meal) and 750 g kg^?1 (palm kernel meal) of the cell wall materials. Neither of the treatments alone was capable of solubilising more than about half of the original NSP. Combined treatment using alkali/chlorite followed by MMNO completely dissolved cell wall material from palm kernel meal, whereas a small residue (40 g kg^?1 of original NSP) was left in sunflower meal. Loss of NSP occurred with both methods (total NSP recovery ranging from 88% for alkali/chlorite extraction of sunflower to 64% for MMNO extraction of palm kernel). Due to differences in solubility revealed upon acidification and/or dialysis, extracts became subdivided into precipitates and soulble fractions. The sugar composition of the resulting fractions enabled a tentative identification of teh major non-starch polysaccharides; sunflower meal was found to contain cellulose, (acidic) xylans, polyuronide-containing fractions and xyloglucan; palm kernel meal was found to contain mannans, cellulose and xylans, with the major part of the mannans originating from the endosperm and the xylans being almost exclusively located in the endocarp.     

Pia Becker (2019) Patientenautonomie und informierte Einwilligung. Schlüssel und Barriere medizinischer Behandlungen

Ethik in der Medizin -