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91.
92.
The nature of the initial carbides formed during the early stages of the tempering of steels is still a matter of debate. Conventionally, the main transition carbide is described as epsilon carbide, with a composition of approximately Fe2.4C. However, earlier one-dimensional atom probe (1DAP) results indicated the existence of carbon-rich regions having much lower carbon contents, with maxima of around 10 at%. There was some uncertainty about the interpretation of the 1DAP results, because of possible problems with alignment of the aperture and with trajectory aberration effects. We have therefore re-visited this topic, using the three-dimensional (3D) atom probe, and studying both a model Fe–Ni–C alloy and a well-known engineering steel (AISI4340). We demonstrate that, for both materials, low-temperature (20–150 °C) aging produces carbon-rich regions with average peak carbon contents of up to 10%. We show for the first time the three-dimensional structure of these carbon-rich regions, and demonstrate that fine-scale faulting exists within them. 相似文献
93.
Karl Speer Peter Horstmann Elke Steeg Thomas Kühn und Alfred Montag 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1990,191(6):442-448
Zusammenfassung Die Bestimmung der ubiquitär verbreiteten Polycyclen bereitet oftmals in Gemüseproben Schwierigkeiten. Vorgestellt werden daher Verfahren, mit denen man eine Abtrennung der störenden Stoffe wie etherische Öle, Wachse, Carotinoide und Chlorophylle erreicht. Als besonders geeignet erweist sich dabei die Reinigung der Probenextrakte an Bio Beads S-X3 und mittels der halbpräparativen HPLC an Kieselgel Si60. Die Polycyclen werden durch CGC/MS bestimmt. Hierdurch ist es möglich, neben den zu bestimmenden Analyten auch die zugesetzten deuterierten Standardverbindungen störungsfrei zu erfassen. Die Resultate 32 verschiedener Gemüseproben werden diskutiert. Höhere Gehalte findet man in Grünkohl- und Petersilienproben.
PAH analysis in vegetable samples
Summary PAH analyses in vegetables are often difficult to carry out; therefore two different clean-up methods, which allow elimination of interfering matrix components such as essential oils, waxes, carotinoids and chlorophylls were developed. Clean-up of 32 different vegetables samples consisted of either Bio-Beads S-X3 chromatography or semi-preparative HPLC on silica gel Si-60. PAH were determined by capillary GC-MS, which allowed the application of deuterium-labelled internal standards. The results are presented; higher PAH contamination was detected in cale and parsley.相似文献
94.
It has been well documented that ascorbate enhances iron uptake, with a proposed mechanism based on reduction to the more absorbable ferrous form. We have performed a study on the effects of ascorbate on ferric iron uptake in the human epithelial Caco-2 cell-line. Ascorbate increased uptake in a concentration-dependent manner with a significant difference between iron uptake and reduction. Uptake kinetics are characteristic of a non-essential activator and the formation of an Fe3+–ascorbate complex. This investigation provides evidence that ascorbate enhances the apical uptake of ferric iron into Caco-2 cells through the formation of a Fe3+–ascorbate complex. 相似文献
95.
Mohr David C.; Beutler Larry E.; Engle David; Shoham-Salomon Varda; Bergan John; Kaszniak Alfred W.; Yost Elizabeth B. 《Canadian Metallurgical Quarterly》1990,58(5):622
This study evaluated the use of pretherapy patient variables as correlates of 3 categorical types of outcome: negative response (negative change of more than 1 normative SEest on depression measure): nonresponse (change within?±?1 SEest on depression measure); and positive response (positive change of more than 1 SEest on depression measure) to psychotherapy among 62 patients with major depressive disorder. By using 4 scales from the Brief Symptom Inventory, the Inventory of Interpersonal Problems, age, and sex, 75.8% of the Ss were correctly classified into the 3 groups. Negative responders were characterized by high levels of interpersonal difficulty and low levels of subjective distress. Nonresponders displayed moderate levels of both interpersonal difficulties and subjective distress. Positive responders displayed high levels of both interpersonal difficulties and subjective distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
96.
Potvin Alfred R. Crosier William G. Fromm Eli Lin James C. Neuman Michael R. Pilkington Theo C. Robinson Charles J. Schneider Lawrence W. Strohbehn John W. Szolovits Peter Tompkins Willis J. 《IEEE transactions on bio-medical engineering》1986,(1):48-59
MORE than 200 years ago, our forefathers made note of man's inalienable rights to life, liberty, and the pursuit of happiness. To the engineering community (applied science in the service of man), these may be coincident with applications to medicine and biology (biomedical engineering), defense, and entertainment. Biomedical engineering research has the distinction, among these three missions, of not only contributing to the quality of human life through the industrial economy but also to life itself?the most fundamental concern of all people. It is through biomedical engineering research that we have been able to learn much concerning the functioning of living systems, and it is through such knowledge that we have been able to develop improved clinical diagnosis, monitoring, and treatment, including life-sustaining devices and aids to the handicapped. Each step represents an improvement in the quality of life, and each step forms the foundation upon which to gain new knowledge to improve upon earlier developments. 相似文献
97.
98.
Alfred Watzl 《产业用纺织品》2008,26(2):47-48
Fleissner的水刺非织造布生产线生产用于揩布产品和医用产品的木浆复合产品,注重于节省原材料成本,降低能耗,保护环境。 相似文献
99.
Cella David; Hughes Chanita; Peterman Amy; Chang Chih-Hung; Peshkin Beth N.; Schwartz Marc D.; Wenzel Lari; Lemke Amy; Marcus Alfred C.; Lerman Caryn 《Canadian Metallurgical Quarterly》2002,21(6):564
The Multidimensional Impact of Cancer Risk Assessment (MICRA) is a new tool to measure the specific impact of result disclosure after genetic testing. The authors compared its performance with that of questionnaires measuring general and cancer-specific distress. Participants (158 women) responded 1 month after they received genetic test results. The women were divided into 4 standard clinical test result groups: BRCA1/2 positive, BRCA1/2 negative, panel negative, and true negative. Factor analysis supported the formation of 3 subscales: Distress (6 items, α= .86), Uncertainty (9 items, α= .77), and Positive Experiences (4 items, α= .75). All 3 MICRA subscales differentiated participants who were BRCAI/2 positive from the other 3 groups. MICRA thus helps identify subgroups of vulnerable genetic testing participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
Alfred Saroli 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,184(2):122-124
Summary This study showed that the bitterness of dipeptide methyl esters depends on the amino acid sequence and that a N-terminall-phenylalanine residue is more effective than some other amino acid residues with hydrophobic side chains. It was observed that dipeptide benzyl esters were notably more bitter than the corresponding methyl esters and that their bitterness depends on the configuration of the C-terminal amino acid. These results exhibit analogies with those obtained with denatonium chloride derivatives, which suggests that the model of interaction with the bitter receptor previously proposed for denatonium chloride is applicable to dipeptides and their ester derivatives.
Struktur — Aktivitätsbeziehung von bitteren Dipeptidestern
Zusammenfassung Diese Studie zeigt, daß die Schwellenwerte der Bitterkeit von Dipeptidmethylestern von der Aminosäuresequenz abhängt und daß ein N-terminalerl-Phenylalaninrest wirksamer ist als andere Aminosäuren mit hydrophoben Seitenketten. Wir haben beobachtet, daß die Dipeptidbenzylester deutlich bitterer sind als die entsprechenden Methylester und daß die Bitterkeit von der Konfiguration der C-terminalen Aminosäure abhängt. Diese Resultate zeigen Ähnlichkeiten mit denen der Derivate von Denatoniumchlorid, woraus zu schließen ist, daß das für Denatoniumchlorid schon früher vorgeschlagene Modell der Wechselbeziehung mit dem Rezeptor der Bitterkeit auf Dipeptide und ihre Ester anwendbar ist.相似文献