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91.
Bending behavior of steel pipes filled with ultralight mortar was studied by bending tests using a steel pipe, steel pipes filled with ultralight mortar, and steel pipes filled with light aggregate concrete and normal concrete. The steel pipe model filled with normal concrete had 1.8 times higher bending strength than the steel pipe model. The bending behavior of the steel pipe filled model with ultralight mortar was not improved when the compressive strength of the ultralight mortar was less than 1 MPa. However, ductility was much improved when the compressive strength was over 5 MPa, and the ultimate steel strain was more than double of the steel pipe model. The strains of steel and concrete in all the models were proportional to the distance from the neutral axis until the steel plate yielded. A simple analytical method was proposed to calculate the bending moments of the ultralight mortar filled steel pipes. The calculated values agreed very well with the test results.  相似文献   
92.
The shear properties of thin films of star and linear polyisoprene (PIP) melts under high pressure were investigated as a function of sliding velocity (shear rate) using the surface forces apparatus. The results were contrasted with their bulk rheological properties; effects of thickness constraint on the shear behavior were discussed. The melts of PIP in bulk exhibit Newtonian-like constant viscosity at least at low shear rates (frequencies), which suggests that individual molecules flow with lateral sliding motion. However, thin films of PIP melts show tribological features involving apparent shear-thinning behavior, indicative of the correlated motions in confined geometries. The shear-property change from bulk rheological behavior to thin-film tribological behavior along with the thickness decrease reflects the physical states and their transitions in the systems; the thickness constraint induces glasslike transitions. Effects of molecular weights and molecular architecture (star-branched or linear) on the shear properties are also discussed.  相似文献   
93.
PURPOSE: Leptin is a recently discovered hormone that appears as a regulator of energy balance. It is important to know whether leptin concentrations are changed under conditions of altered energy homeostasis. Consequently, we examined the effects of exercise with fasting and exercise with feeding on circulating leptin concentrations in healthy men and in type 1 diabetic patients with normal body weight and well controlled diabetes. METHODS: Leptin concentrations were determined with radioimmunoassay. RESULTS: During a 3-h cycle ergometer exercise with fasting, leptin decreased by 42% (P < 0.01) in nine healthy men and by 23% (P = 0.05) in eight male type 1 diabetic patients. Leptin fell equally by 12% (P < 0.03) both in nine healthy men and in eight male type 1 diabetic patients who were studied as a resting control group. The absolute fall in leptin in healthy men was similar in the exercise and resting control groups (0.8 +/- 0.1 microgram.L-1 vs 0.8 +/- 0.2 microgram.L-1). However, due to lower leptin concentration before the exercise, the relative decrease (42%) was greater than during the resting control study (12%, P < 0.005). This difference was not seen in the diabetic patients. Fasting leptin concentration correlated positively with BMI (r = 0.75, P < 0.001) and fasting insulin (r = 0.71, P < 0.01) in healthy men as well as with insulin level (r = 0.54, p < 0.05) in type 1 diabetic patients. When exercise was performed with feeding, and this was associated with a significant rise in serum cortisol level (marathon run, 14 healthy men and 7 type 1 diabetic patients), leptin concentration did not change significantly. CONCLUSIONS: 1) During morning hours, leptin decreases both in healthy men and in type 1 diabetic patients, reflecting a diurnal variation of leptin concentration and the effect of fasting on leptin concentration. 2) The fall in leptin during morning hours is augmented by physical exercise in healthy men. 3) If exercise is performed with feeding and associated with a rise in serum cortisol level, leptin concentration remains unchanged. These data suggest that although exercise may reduce circulating leptin levels, the effect is small and can be counterbalanced by feeding or a rise in serum cortisol concentration.  相似文献   
94.
In order to investigate the overall atomic hydrogen background and the dynamic characteristics of wall pumping/fuelling phenomenon, a permeation probe system has been developed and applied in the spherical tokamak QUEST. Reliability of measurements, within ±3% accuracy and a positive correlation with the hydrogen line emission over three orders of magnitude have been demonstrated for more than 3000 various plasma discharges. By comparison of the experimental permeation (flux) curves with the numerically simulated curves, the net incident atomic hydrogen flux is evaluated in the range of 1 × 1019 H m?2 s?1 to 4 × 1020 H m?2 s?1. The atomic flux has been investigated as a function of various plasma operation parameters like RF power, gas pressure and magnetic configuration. Using the static particle balance and permeation measurements, the progress in wall conditioning has been investigated. An inverse correlation between the atomic hydrogen flux and improvement in wall pumping has been observed over the two campaigns.  相似文献   
95.
Natural motion animation through constraining and deconstraining at will   总被引:1,自引:0,他引:1  
This paper presents a computational technique for creating whole-body motions of human and animal characters without reference motion. Our work enables animators to generate a natural motion by dragging a link to an arbitrary position with any number of links pinned in the global frame, as well as other constraints such as desired joint angles and joint motion ranges. The method leads to an intuitive pin-and-drag interface where the user can generate whole-body motions by simply switching on or off or strengthening or weakening the constraints. This work is based on a new interactive inverse kinematics technique that allows more flexible attachment of pins and various types of constraints. Editing or retargeting captured motion requires only a small modification to the original method, although it can also create natural motions from scratch. We demonstrate the usefulness and advantage of our method with a number of example motion clips.  相似文献   
96.
The pathophysiology of early-stage hip osteoarthritis (EOA) is not fully understood. Although a previous study in an age-unmatched cohort reported that the number of macrophages was increased in knee EOA compared to late OA (LOA), it remained unclear whether increased macrophages in EOA accurately reflect EOA pathology. We investigated the differences in CD14 expression levels between EOA and LOA using age-unmatched and -matched cohorts. Synovial tissues were obtained from 34 EOA (Tönnis grades 0 and 1) and 80 LOA (Tönnis grades 2 and 3) patients. To correct for differences in demographics between patients with LOA and EOA, we also created propensity score-matched cohorts (16 EOA and 16 LOA). CD14 expression and its association with pain was estimated in LOA and EOA before and after propensity matching. We performed flow cytometry on tissues from the 16 patients, with 8 from each group, to assess for CD14+ subsets in the cells. The CD14 expression in EOA was higher than that in LOA both before and after propensity matching. The proportion of CD14high subsets in EOA was higher than that in LOA. The CD14 expression was associated with pain in EOA before matching. However, no difference was observed between the pain and CD14 expression after matching in EOA. The increased CD14 expression and the proportion of CD14high subsets may be important features associated with hip EOA pathology. To accurately compare early and late OA, the analysis of a propensity score-matched cohort is necessary.  相似文献   
97.
98.
The development of tissue clearing technologies allows 3D imaging of whole tissues and organs, especially in studies of the central nervous system innervated throughout the body. Although the three-dimensional imaging of solvent-cleared organs (3DISCO) method provides a powerful clearing capacity and high transparency, the rapid quenching of endogenous fluorescence and peroxide removal process decreases its practicability. This study provides a modified method named tDISCO to solve these limitations. The tDISCO protocol can preserve AAV-transduced endogenous EGFP fluorescence for months and achieve high transparency in a fast and simple clearing process. In addition to the brain, tDISCO was applied to other organs and even hard bone tissue. tDISCO also enabled us to visualize the long projection neurons and axons with high resolution. This method provides a fast and simple clearing protocol for 3D visualization of the AAV- transduced long projection neurons throughout the brain and spinal cord.  相似文献   
99.
Recently, it was demonstrated that the expression of BMAL1 was decreased in the endometrium of women suffering from recurrent spontaneous abortion. To investigate the pathological roles of uterine clock genes during pregnancy, we produced conditional deletion of uterine Bmal1 (cKO) mice and found that cKO mice could receive embryo implantation but not sustain pregnancy. Gene ontology analysis of microarray suggested that uterine NK (uNK) cell function was suppressed in cKO mice. Histological examination revealed the poor formation of maternal vascular spaces in the placenta. In contrast to WT mice, uNK cells in the spongiotrophoblast layer, where maternal uNK cells are directly in contact with fetal trophoblast, hardly expressed an immunosuppressive NK marker, CD161, in cKO mice. By progesterone supplementation, pregnancy could be sustained until the end of pregnancy in some cKO mice. Although this treatment did not improve the structural abnormalities of the placenta, it recruited CD161-positive NK cells into the spongiotrophoblast layer in cKO mice. These findings indicate that the uterine clock system may be critical for pregnancy maintenance after embryo implantation.  相似文献   
100.
The tensile strengths and elongations of starch films prepared from various unmodified and modified starches were measured. These properties were improved by addition of urea and polyvinyl alcohol to the starch paste. The results obtained were as follows.
  • 1 The heating temperature greatly affected the tensile strength and elongation of various unmodified starches. Potato starch gave the best film.
  • 2 Introduction of hydroxyethyl groups into corn starch had unexpectedly little affect on the properties of the films.
  • 3 A combination of hydroxyethylation and acid-modification slightly improved the properties of the films.
  • 4 No film could be obtained after combinations of hydroxyethylation and hypochlorite-oxidation, pyrodextrinization or α-amylase-dextrinization. However, addition of urea to these modified starches resulted in good films.
  • 5 On addition of urea the elongation of starch films increased and the pastes adhered uniformly to water repellent surfaces.
  • 6 A film with the best properties was prepared from a mixture of 67% acid-modified hydroxyethyl starch, 13% urea and 20% polyvinyl alcohol.
  相似文献   
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