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61.
Russian Journal of Nondestructive Testing - The results of measuring residual strains/stresses in the VAMAS international calibration block with the STRESS neutron diffractometer installed in the... 相似文献
62.
Amorphous Fe(95?x)Sn5Bx ribbons (x = 15, 17, 20) were prepared for the first time by planar-flow casting. Their thermodynamic stability and kinetics of crystallization were studied by differential thermal analysis, differential scanning calorimetry and magnetometry (thermobalance with permanent magnet). Formation of crystalline phases and their morphology were analyzed by X-ray diffraction and transmission electron microscopy. The results indicate the existence of critical composition for the transformation kinetics. The relation between the magnetic state of the material and the kinetics of crystallization was analyzed. 相似文献
63.
64.
Residual stress determination in a thick ferritic steel weld plate using neutron diffraction 总被引:1,自引:0,他引:1
The distribution of residual stresses was determined through the thickness of a 50-mm thick ferritic steel weld plate using (110) and/or (211) diffraction peaks. We proposed a two-peak combined methodology, which uses (110) and (211) peaks designed to have neutron wavelengths of 2.39 and 1.55 Å, respectively, in order to locate the neutron cross-section at each local minimum. The result shows that the available penetration path length can be maximized by (110) diffraction for the transmission geometry and (211) diffraction for the reflection geometry of the plate specimen. Furthermore, the stress components by the two peaks were similar to the results of the conventional one-peak measurement due to the same diffraction elastic constants between the (110) and (211) peaks in the bcc ferritic steel. Such appropriately combined two-peak method can significantly enhance the deep penetration capability for the determination of residual stresses in an extra thick steel plate specimen. 相似文献
65.
Modulation of VEGF signaling in a mouse model of diabetes by xanthohumol and 8‐prenylnaringenin: Unveiling the angiogenic paradox and metabolism interplay
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66.
de Araujo TL Lopes MV Cavalcante TF Guedes NG Moreira RP Chaves ES da Silva VM 《Archivos latinoamericanos de nutrición》2006,56(3):216-223
The evaluation of blood pressure and anthropometric measurements is important for evaluating the health of children and teenagers, since cardiovascular abnormalities are becoming more and more common in this population. The objective of this study was to analyze the correlation between anthropometric measurements and arterial pressure taking gender, age and the practice of physical activities into consideration. A cross sectional study was carried out in a school in the city of Fortaleza, Ceará, Brazil, in a sample of 122 students of 6-18 years of age. Data was collected on a specific form and included sociodemographic data, anthropometric evaluation, measurement of arterial pressure and the practice of physical activity. Three measurements were taken of each anthropometric variable and arterial pressure, and the respective means were calculated. Data were processed and analyzed using the SPSS software program, version 13.0. Significance was established at 5% (p < 0.05). A correlation was identified between arterial pressure and tricipital skinfold thickness. No statistically significant differences were found between the mean anthropometric measurements and the presence of high blood pressure. A correlation was found between body mass index and abdominal and subscapular skinfold thickness and between body mass index and waist and hip circumference. Physical activity had no effect on anthropometric measurements. Females had a higher mean tricipital and abdominal skinfold thickness than males. This study confirms the influence of the variables of gender and age on the anthropometric measurements evaluated. In particular, tricipital skinfold thickness was correlated with systolic arterial pressure. 相似文献
67.
Gil M Ramírez JA Pla M Ariño B Hernández P Pascual M Blasco A Guerrero L Hajós G Szerdahelyi EN Oliver MÁ 《Meat science》2006,72(1):121-129
The effect of selection for growth rate on the degradation of the myofibrillar proteins and on meat texture properties of rabbit longissimus muscle at two ageing times (1 and 7 days) was studied as well as its effect on the proteolytic potential of the muscle. Two groups of contemporary animals (20 rabbits per group), one selected for growth rate (S) for 14 generations and the other unselected control group (C) were compared. The control group was formed from the offspring of the embryos belonging to the 7th generation and was compared with selected animals belonging to 21st generation. Myofibrillar protein degradation was studied by SDS-PAGE electrophoresis (12.5% and 4-15% polyacrylamide gels) followed by densitometric analysis of the pherograms. Texture properties were evaluated by Warner-Bratzler (WB) test and Texture profile analysis (TPA). The activities of proteolytic enzymes calpains and cathepsins and of their inhibitors were determined in the muscle at 24h. Densitometric analysis of the pherograms of samples aged 7 days showed an extra 30kDa band and the disappearance of a band with higher molecular weight than the myosin heavy chain with respect to samples aged 24h in both groups of rabbits. TPA results showed that cohesiveness was significantly lower in meat at 7 days than at 24h (P<0.0001), whereas springiness and chewiness presented a clear tendency to be lower at 7 days than at 24h (P=0.0646 and P=0.0764, respectively). Regarding the genetic type, S animals presented higher hardness and chewiness than C rabbits. Shear firmness (WB test) was significantly (P<0.0001) higher for S group, whereas no significant differences in shear force and area were found. No significant effect (P>0.05) of ageing time was detected using WB test. Selection for growth rate did not affect the activities of proteolytic enzymes or their inhibitors. 相似文献
68.
Dr. Charlène Gadais Kevin Van holsbeeck Dr. Samuel L. C. Moors Dr. Dieter Buyst Dr. Krisztina Fehér Prof. Kristof Van Hecke Prof. Em. Dirk Tourwé Prof. Thierry Brigaud Dr. Charlotte Martin Prof. Frank De Proft Prof. Julien Pytkowicz Prof. José C. Martins Dr. Grégory Chaume Prof. Steven Ballet 《Chembiochem : a European journal of chemical biology》2019,20(19):2513-2518
Proline is often found as a turn inducer in peptide or protein domains. Exploitation of its restricted conformational freedom led to the development of the d -Pro-l -Pro (corresponding to (R)-Pro–(S)-Pro) segment as a “templating” unit, frequently used in the design of β-hairpin peptidomimetics, in which conformational stability is, however, inherently linked to the cis–trans isomerization of the prolyl amide bonds. In this context, the stereoelectronic properties of the CF3 group can aid in conformational control. Herein, the impact of α-trifluoromethylated proline analogues is examined for the design of enhanced β-turn inducers. A theoretical conformational study permitted the dipeptide (R)-Pro–(R)-TfmOxa (TfmOxa: 2-trifluoromethyloxazolidine-2-carboxylic acid) to be selected as a template with an increased trans–cis rotational energy barrier. NMR spectroscopic analysis of the Ac-(R)-Pro–(R)-TfmOxa–(S)-Val-OtBu β-turn model, obtained through an original synthetic pathway, validated the prevalence of a major trans–trans conformer and indicated the presence of an internal hydrogen bond. Altogether, it was shown that the (R)-Pro–(R)-TfmOxa template fulfilled all crucial β-turn-inducer criteria. 相似文献
69.
Gastric acid and serum gastrin (radioimmunoassay) responses to insulin (0.2 U/kg i.v.) and 2-deoxy-D-glucose (2DG) (50 mg/kg i.v.) were determined in 11 male duodenal ulcer patients before and after partial gastrectomy involving complete antral resection. In 8 of the patients the acid response to pentagastrin (6 mug/kg subc.) was also determined. Before operation, 2DG produced higher acid and gastrin responses than insulin. Partial gastrectomy reduced basal acid secretion by 54% but did not alter the basal gastrin level, suggesting that this gastrin is of extra-antral origin. Partial gastrectomy reduced the acid responses to insulin and 2DG by 66% and 78%, respectively; after operation the acid responses to these stimulants were equal. The ratio for the acid response to insulin and pentagastrin was 65% before and 56% after partial gastrectomy; corresponding ratios for 2DG and pentagastrin were 112% and 48%. Partial gastrectomy abolished the peak gastrin response to insulin hypoglycemia and reduced that to 2DG by 64%. The integrated gastrin response to insulin and 2DG was insignificant in the operated patients. Both insulin and 2DG release mainly antral gastrin which appears to be of greater importance for the acid response to 2DG than insulin. 相似文献
70.
Networked cryptographic devices resilient to capture 总被引:1,自引:1,他引:0
Philip?MacKenzieEmail author Michael K.?ReiterEmail author 《International Journal of Information Security》2003,2(1):1-20
We present a simple technique by which a device that performs private key operations (signatures or decryptions) in networked applications and whose local private key is activated with a password or PIN can be immunized to offline dictionary attacks in case the device is captured. Our techniques do not assume tamper resistance of the device but rather exploit the networked nature of the device in that the devices private key operations are performed using a simple interaction with a remote server. This server, however, is untrusted – its compromise does not reduce the security of the devices private key unless the device is also captured – and need not have a prior relationship with the device. We further extend this approach with support for key disabling, by which the rightful owner of a stolen device can disable the devices private key even if the attacker already knows the users password. 相似文献