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91.
The incidence of stress fractures is increasing among competitive and recreational athletes as well as among children and the elderly. By understanding the continuum of bone's response to stress and maintaining an appropriate index of suspicion, the health care provider can diagnose these injuries appropriately. An accurate history and examination is essential and will differentiate stress fractures from other stress reactions. The more common stress fractures are discussed. 相似文献
92.
PURPOSE: Normal retina is firmly attached to the retinal pigment epithelium, but the force of this adhesion drops precipitously within the first 2-3 min after enucleation. The purpose was to study metabolic factors that might be relevant to this postmortem failure of adhesion. METHODS: Dutch rabbit retina was manually peeled from the retinal pigment epithelium on strips of enucleated eyecup within a 37 degrees C bath. Retinal adhesiveness was measured by observing the amount of retinal pigment epithelium that remained adherent to the retina. RESULTS: Autologous whole blood in place of salt solution retarded the decrease in adhesiveness. A solution of hemoglobin alone was similarly effective, whereas methemoglobin solution failed to help the persistence of retinal adhesion. Bubbling oxygen into the salt solution and circulating it to avoid oxygen depletion at the tissue boundary also proved effective at sustaining retinal adhesiveness. Eyes made ischemic in vivo for 5 min or longer, by elevating intraocular pressure, showed virtually no retinal adhesion when enucleated immediately thereafter. However, eyes made ischemic for 10 min, but allowed to regain circulation for 5 min before enucleation, showed a return of retinal adhesiveness to 80% of normal. CONCLUSIONS: Oxidative metabolism is critical to the maintenance of retinal adhesiveness, and the effects of oxygen deprivation on adhesion are reversible within a certain time period. 相似文献
93.
94.
Sulfonylureas have, in the past, been reported to have adverse cardiovascular effects. Glimepiride is a new sulfonylurea. In spite of stimulating less insulin secretion, it has, depending on the species, equal or higher blood glucose decreasing activity and according to preliminary studies less cardiovascular activity than glibenclamide. Further studies were performed to confirm the lower cardiovascular activity of glimepiride. The IC50 for inhibition of rilmakalim-activated KATP channel currents in isolated ventricular myocytes was 31.6 nM for glimepiride and 6.8 nM for glibenclamide. In endotoxin shock-rats at a dose of 1 x 2 mg/kg i.v., glibenclamide induced a significantly higher blood pressure increase than glimepiride. At two i.v. doses of 20 mg/kg 4 min apart, in normal rats, glibenclamide produced signs of ischemia in the ECG in nearly all animals, glimepiride almost none, in diabetic rats, glibenclamide produced in all animals a lethal cardiogenic shock preceeded by serious ECG changes, glimepiride only in one fifth of the animals. In open-chest dogs, on intracoronary infusion of equieffective blood glucose-lowering doses, glibenclamide, gliclazide and glimepiride all reduced coronary blood flow, increased coronary resistance, depressed the mechanical activity of the heart, enhanced myocardial O2-extraction, reduced the serum potassium level and induced a moderate endocardial ST-segment elevation, but glimepiride to a significantly less extent than glibenclamide and gliclazide. The presented data confirm that glimepiride at equivalent blood glucose decreasing doses has less cardiovascular activity than conventional sulfonylureas. 相似文献
95.
The third-order nonlinear optical susceptibilities, X(3), of TeO2-based glasses containing transition metal oxides (M = Sc2O3, TiO2, V2O5, Nb2O5, MoO3, Ta2O5, and WO3) glasses have been measured by the third harmonic generation (THG) method in order to investigate the effect of the empty d-orbital contributions to the third-order nonlinear optical susceptibilities. It is found that the addition of TiO2, Nb2O5, and WO3 to TeO2 glass increases the X(3) value as well as the refractive index, while others decrease both of them. The positive effect of the TiO2, Nb2O5, or WO3, on the X(3) of TeO2 glass was interpreted in terms of the cationic empty d-orbital contribution. There is an almost linear relation between the X(3) and the term (n2ω+ 2)3.(n2ω -1).Ed/E20 containing three measurable parameters only, irrespective of the kinds of MO, which was derived based on the bond orbital theory developed by M. E. Lines. The largest X(3) value obtained is 1.69 × 10−12 esu for 30NbO2.5.70TeO2 glass, about 60 times larger than that of pure fused silica glass. 相似文献
96.
Consistent calculation of fugacities of fluid mixtures remains as one of the most important subjects in contemporary molecular
thermodynamics. In practice, equations of state (EOSs) and gE-models have been used. However, most EOSs are erroneous for condensed phases at high densities and gE-models are inapplicable for pressuresensitive systems. Recently to remedy the shortcomings in both approaches, there has
been a surge of new gE-EOS mixing rules. By equating any set of EOS and gE-models, the limitations in both approaches could be resolved significantly. However, the self-consistency in the underlying
concept of those mixing rules remains controversial. During the last several years, the present authors proposed a new lattice-fluid
EOS and its simplification relevant to phase equilibrium calculations. Without employing any gE-EOS mixing rule and with only two parameters for a pure component and one adjustable interaction energy parameter for a binary
mixture, results obtained to date demonstrated that the EOSs are quantitatively applicable to a great variety of phase equilibrium
properties of mixtures, especially, for complex and/or macromolecular systems. In the present article we summarize the EOSs
and extended the applications to liquid-liquid Equilibria. In part I, we discussed briefly the molecular thermodynamic aspects
of general derivation of the EOS and a brief discussion of applying the EOSs to pure fluids while the illustrative application
to various real mixture systems is discussed in part II. 相似文献
97.
A. Inoue B. G. Kim K. Nosaki T. Yamaguchi T. Masumoto 《Journal of Materials Science Letters》1992,11(12):865-867
On leave from: Honda Research and Development Co., Ltd, Wako 351-01, Japan. 相似文献
98.
The crystallization of poly(phenylene sulfide) (PPS) in a polymer–magnetic Nd—Fe—B powder suspension was studied. Isothermal crystallization behavior was analyzed by way of differential scanning calorimetry, and the kinetics were described via the Avrami equation. The Avrami parameters and the crystallization times were strongly affected by both the particle size and the presence of a coupling agent coated on the filler particles. The small Nd—Fe—B particles exhibited long induction and half‐times, whereas the large particles tended to have short crystallization times. Particles ranging from 38 to 150 μ appeared to have similar crystallization times and to have no significant change in the value of Avrami index with melt crystallization temperature. As a result of these analyses, the dynamic mechanical properties were determined to correlate the fundamental polymer crystallization characteristics and the physical properties of the PPS binder. The enhancement of the wetting of the filler to the binder was promoted through the coupling agent, as confirmed by dynamic mechanical testing performed on the samples. The storage modulus typically decreased because of the presence of the uncoated small particles. Conversely, the loss modulus was enhanced because of the presence of the coated small particles in the PPS binder. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1091–1102, 2002 相似文献
99.
100.
KW Scheller J G?rres JG Ross M Wiescher R Harkewicz DJ Morrissey BM Sherrill M Steiner NA Orr JA Winger 《Canadian Metallurgical Quarterly》1994,49(1):46-50
The shortage of suitable liver donors for children has motivated the use of ABO-incompatible (ABO-I) grafts for transplantation in urgent situations. However, survival after ABO-I liver grafts has been reported at about 30% as compared with 80% in cases of ABO-identical or -compatible liver grafts. This difference has been attributed to antibody-mediated, hyperacute or chronic liver rejection, due to preformed ABO antibodies (alloantibodies). In this study, we report our results with ABO-I livers in children without alloantibodies at the time of transplantation. From January 1988 to June 1993, 143 OLT were performed in 122 children. Eight children received 8 ABO-I liver grafts. Of these, 7 patients were included in the study. All 7 were alloantibody free before OLT. Five children were spontaneously alloantibody free, while in 2 children, the plasma alloantibodies were eliminated before and after transplantation using intravenous infusion of specific blood group antigens of the donor blood group (soluble antigens). Immunosuppression consisted of a triple-drug treatment combining CsA, AZA, and steroids. The follow-up period was between 10 and 48 months. One child died from a surgical complication. Six children survived, but 1 died 10 months later from intestinal obstruction. There were no graft losses and no episodes of hyperacute or chronic rejection. The graft and patient survival rate was 71%. There was a 28% incidence of rejection, but all were mild (requiring steroid boluses only). Our results suggest that the absence of ABO alloantibodies at the time of and after transplantation can protect ABO-I liver grafts against antibody-mediated rejection, whether hyperacute or chronic, and that soluble antigens are effective in eliminating alloantibodies in children. 相似文献