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951.
G Raviv JP Vanegas M Petein C Schulman A Danguy R Kiss E Wespes 《Canadian Metallurgical Quarterly》1997,158(5):1778-1782
PURPOSE: The objectives of this study were to quantify the immunohistochemical stainings of collagen types I, III and IV, and investigate the value of glycohistochemical staining with 3 lectin types specific to a particular glycan structure, Arachis hypogaea, Triticum vulgare and concanavalin A, as a method of defining possible changes in the collagen structure of the tunica albuginea in potent and impotent patients. MATERIALS AND METHODS: The study involved 4 normal men, 4 with pure venous leakage and 4 with pure arterial disease. Collagen types I, III and IV, and lectins Arachis hypogaea, Triticum vulgare and concanavalin A were studied using a cell image processor. The labeling index relates to the percentage of staining and mean optical density relates to the staining intensity. RESULTS: Mean labeling index values for the 3 types of collagen and lectins were similar (p > 0.05). Mean optical density value relating to collagen type I was significantly higher in the arteriogenic group than in the other groups (p < 0.05), while mean optical density value of collagen type IV was significantly higher in the venogenic group than in the 2 other groups (p < 0.05). Mean optical density values relating to the 3 lectin types were similar in the 3 clinical groups (p > 0.05). CONCLUSIONS: An alteration in the distribution and structure of the various collagen types and lectins in the tunica albuginea of impotent patients has been shown that may interfere with normal function and lead to impotence. 相似文献
952.
R Beyer H Burghardt R Reich E Thomas T Gessner D.R.T Zahn 《Microelectronics Reliability》1998,38(2):144
Thin SiO2 and SiOxNy layers were grown on silicon using Rapid Thermal Processing (RTP) in either O2 or N2O ambient. Subsequent annealing or nitridation was performed in order to improve the electrical stability. The composition of the films, in particular the incorporation of nitrogen and hydrogen, has been studied. We obtained the distribution of states at the Si/insulator interface through the evaluation of CV measurements and investigated the charge trapping in the layers analysing the voltage–time behaviour during Fowler–Nordheim constant current injection. Furthermore, assuming a trap assisted tunneling mechanism, the influence of near interface trap states on the current voltage characteristic was used to derive an effective insulator state distribution. 相似文献
953.
An investigation has been carried out into the possibility of in situ formation of MoS2 within porous anodic films on aluminium, to improve subsequent tribological behaviour, by re-anodizing in thiomolybdate electrolyte. Acidification of thiomolybdate was employed to simulate the conditions for formation of the sulphide at the anodic film/electrolyte interface, followed by appropriate vacuum heat treatments to study possible temperature effects on the sulphide due to either friction or Joule heating during anodizing. The products of both acidification and heat treatment, characterized by X-ray powder diffraction and scanning electron microscopy, were compared with those formed by direct thermal decomposition of ammonium tetrathiomolybdate crystals. The precipitate formed by acidification was mainly amorphous molybdenum trisulphide (MoS3), which on heat treatment at 450 and 850°C yielded 3R-MoS2. 3R-MoS2 also formed by the thermal decomposition of thiomolybdate crystals. Thermogravimetric and differential thermal analyses showed that the decomposition of MoS3 to MoS2 occurred in the range 220–370°C and revealed the sequence of reaction steps. The findings suggest that mainly amorphous MoS3 is formed as a consequence of changes in the pH of the film/electrolyte interface during re-anodizing but the product is relatively easily transformed to crystalline MoS2 on moderate heating which may occur during wear processes. 相似文献
954.
The aim of this research was to determine if circadian rhythms have an effect on time trial cycling performance of 15 min duration. Seven males (Mean+/-SD): age, 22.3+/-4.9 yr; height 179.0+/-7.9 cm, body mass 74.5+/-15.5 kg; VO2max 68.0+/-5.7 ml x kg(-1) x min(-1) who were all competitive cyclists or triathletes with previous experience in laboratory testing procedures volunteered to participate in this study. Each of the seven subjects underwent a series of four tests; one VO2 max test, and three 15 min maximal performance tests, at varying times during a 24 hr period. Testing times were at 08.00-10.00; 14.00-16.00 and 20.00-22.00 hours. Heart rate was recorded during the last 10-15 seconds of each minute and blood lactate levels were taken at 5 and 10 min during exercise and again immediately post-exercise. O2 consumption was measured continuously using open circuit spirometry. RPE was measured using the Borg scale at 5 and 10 min during, and again immediately following the completion of testing. Resting oral temperature was the only variable to show a significant time of day effect (p<0.05). Oral temperature during the afternoon was higher than both morning and evening results by 0.76 degrees C and 0.09 degrees C respectively. Total work (kJ) and average power output (W) were recorded at their highest during the morning session and reached a trough during the afternoon session, but these differences were not significant (p = 0.9997 and 0.9972 respectively). The results obtained in this study indicate that while certain biological rhythms are present, they appear to have no effect on this type of cycling performance. Although athletic performance may be enhanced by training programs that are compatible with an individuals body clock, the ability to perform and train at various times has an adaptive response which appears to over-ride these naturally inherent rhythms. 相似文献
955.
D Brown S Kogan E Lagasse I Weissman M Alcalay PG Pelicci S Atwater JM Bishop 《Canadian Metallurgical Quarterly》1997,94(6):2551-2556
The malignant cells of acute promyelocytic leukemia (APL) contain a reciprocal chromosomal translocation that fuses the promyelocytic leukemia gene (PML) with the retinoic acid receptor alpha gene (RAR alpha). To test the hypothesis that the chimera PMLRAR alpha plays a role in leukemogenesis, we expressed a PMLRAR alpha cDNA in myeloid cells of transgenic mice. PMLRAR alpha transgenic mice exhibited impaired neutrophil maturation early in life, which progressed at a low frequency over the course of several months to overt APL. Both the preleukemic state and the leukemia could be transplanted to nontransgenic mice, and the transplanted preleukemia could progress to APL. The APL recapitulated features of the human disease, including a response to retinoic acid. Retinoic acid caused the leukemic cells to differentiate in vitro and in vivo, eliciting remissions of both the preleukemic state and APL in mice. Our results demonstrate that PMLRAR alpha impairs neutrophil differentiation and initiates the development of APL. The transgenic mice described here provide an apparently accurate model for human APL that includes clear evidence of tumor progression. The model should be useful for exploring the molecular pathogenesis of APL and the mechanisms of the therapeutic response to retinoic acid, as well as for preclinical studies of therapeutic regimens. 相似文献
956.
Bartolo A. Clymer B.D. Burgess R.C. Turnbull J.P. 《Signal Processing, IEEE Transactions on》1998,46(8):2243-2248
A new method of implementing efficient FIR filters is presented. It involves approximation of an equiripple FIR by a rounding operation and application of the derived impulse response by a simple recursive equation. The technique is extremely efficient for lowpass, highpass, bandpass, and bandstop filters with sharp transitions and low edge frequencies 相似文献
957.
Based on a contemporary cognitive-psychoanalytic theory (control-mastery theory; J. Weiss, H. Sampson, & Mount Zion Psychotherapy Research Group, 1986), this study proposed that college students have plans for college that consist of conscious and unconscious goals and obstructions to be overcome in meeting those goals. The construct of unconscious guilt was used to mediate the dual goals of autonomy and attachment. The idiographic plan-formulation method was adapted to derive plans for 12 sophomore women. Acceptable interjudge reliabilities and criterion validity were demonstrated, and several themes in the goals and obstructions were illustrated. Students worried more about mothers than about fathers, particularly when they perceived the mother as weak or needy. The potential of the method for generating inferences about unconscious process for normative development is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
958.
One of many problems to be faced when assessing in vivo human muscle mitochondria respiration by phosphorus magnetic resonance spectroscopy (31P-MRS) is the definition of the correct reference population and the values of reference range. To take into account most factors that influence muscle activity as age, sex, physical activity; nutritional state etc., an exceedingly high number of different reference groups are needed. To overcome this problem we developed specific tests to assess separately in vivo the activity and the functionality of muscle mitochondria by 31P-MRS in clinical settings. By activity we refer to muscle whole metabolic activity, i.e. the total oxidative capacity of muscle mitochondria which is influenced by many factors (age, sex, physical activity, nutritional state etc.). By functionality we refer to the qualitative aspects of mitochondrial respiration which depends on the integrity of mitochondrial multienzyme systems and on substrate availability. Our tests have been experienced on some 1200 patients and are currently used to detect deficits of mitochondrial respiration and ion transport in patients with suspected primary or secondary muscle mitochondrial malfunctioning. 相似文献
959.
The cytosolic chaperonin containing TCP-1 (CCT) is known to keep fold cytoskeletal proteins and is involved in the proper organization of the cytoskeleton. These studies are based on the assumption that growth responses linked to structural rearrangement of the plant cytoskeleton include the action of CCT and the need for newly synthesized tubulin. The presence of the alpha- and epsilon-subunits of CCT was investigated in soluble fractions of protein extracts from maize mesocotyls and coleoptiles at distinct growth stages. The CCT-subunits, tubulins and actin decreased in the coleoptile in response to far-red light. In addition, independent from light treatment, the amount of CCT epsilon abundance declined with age in coleoptiles and mesocotyls between 2 and 4.5 days after sowing. In contrast to CCT epsilon, no significant light regulation of CCT alpha was found in the mesocotyl. In two day old, light-grown rapidly elongating coleoptiles part of the CCT alpha subunit and the bulk of actin and tubulin was found shifted into fractions of high molecular weight complexes when compared to slowly elongating, dark grown coleoptiles. In 4.5 day old, etiolated and elongating coleoptiles, part of both CCT-subunits and cytoskeleton proteins were found in fractions of high molecular weight. A complete disappearance of these polypeptides was observed in old far-red irradiated growth-arrested coleoptiles. CCT epsilon was found to be colocalized to microtubular structures and to the nucleus. We conclude from our data that abundance of CCT-subunits in soluble extracts is dependent on age and light treatment, but independent from the growth stage of mesocotyl and coleoptile. 相似文献
960.
Interleukin-7 (IL-7) is a proteinaceous biological response modifier that has a bioactive tertiary structure dependent on disulfide bond formation. Disulfide bond assignments in human (h)IL-7 are based upon the results of matrix-assisted laser desorption/ionization (MALDI) mass spectroscopy and Cys to Ser mutational analyses. A gene encoding the hIL-7 was synthesized incorporating Escherichia coli codon usage bias and was used to express biologically active protein as determined by stimulation of precursor B-cell proliferation. MALDI mass spectroscopic analysis of trypsin-digested hIL-7 was performed and compared with the anticipated results of a simulated tryptic digestion. Many of the anticipated hIL-7 tryptic fragments were detected including one with a molecular mass equivalent to the sum of two polypeptides linked through a disulfide bond formed from Cys residues (Cys3 and Cys142). Subsequently, Cys to Ser substitution mutational analyses were performed. A hIL-7 variant with all six Cys substituted with Ser was found to be biologically inactive (EC50 > 1 x 10(-7) M). In contrast, a family of single disulfide bond-forming variants of hIL-7 were constructed by reintroducing Cys pairs (Cys3-Cys142, Cys35-Cys130, and Cys48-Cys93), and each could stimulate cell proliferation with an EC50 of 4 x 10(-9), 2 x 10(-8), and 2 x 10(-9) M, respectively. In single disulfide bond-forming mutants of hIL-7, the ability to stimulate cell proliferation was abolished in the presence of 2 mM dithiothreitol. The results presented strongly suggest that only a single disulfide bond is required for hIL-7 to form a tertiary structure capable of stimulating precursor B-cell proliferation. 相似文献