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排序方式: 共有866条查询结果,搜索用时 31 毫秒
11.
G. Mestres F. Niefloud R. Fortune J. M. Devoisselle R. Marti H. Maillols 《Drug development and industrial pharmacy》1996,22(12):1193-1199
This paper reports a study undertaken using techniques of static and dynamic light scattering to investigate the influence of sodium salicylate and methyl salicylate on droplet size of oil-in-water emulsions. The rates of changes were measured by determining the size and distribution of the oil droplet in the material. All emulsions showed a bimodal size distribution; the mean diameters and polydispersity were calculated from intensity. These data were analyzed with nonlinear regressions and bootstrap methodology. An amount of methyl salicylate component induced a decrease of mean diameter and standard deviation. On the contrary, sodium salicylate entailed the growth of all droplet populations and coalescence for the highest concentration. 相似文献
12.
Experimental results on adiabatic coupling into SOI photonic Crystal coupled-cavity waveguides 总被引:1,自引:0,他引:1
P. Sanchis J. Marti W. Bogaerts P. Dumon D. Van Thourhout R. Baets 《Photonics Technology Letters, IEEE》2005,17(6):1199-1201
The experimental implementation of an adiabatic coupling technique for efficient coupling between photonic crystal single-line defect waveguides and coupled-cavity waveguides is reported. The samples were fabricated in a silicon-on-insulator substrate using 248-nm-deep ultraviolet lithography. Experimental results are compared with three-dimensional (3-D) finite-difference time-domain simulations. Furthermore, the discrepancies between two-dimensional and 3-D simulation results are analyzed. 相似文献
13.
S. Haacke M. Hartig D. Y. Oberli B. Deveaud E. Kapon U. Marti F. K. Reinhart 《Solid-state electronics》1996,40(1-8):299-302
The mechanisms of carrier transfer from barrier regions (superlattices, side-wall and vertical quantum wells) into arrays of quantum wires are investigated by time-resolved photoluminescence. The wires are grown by different techniques on V-groove substrates. The transfer times range from 25 to 900 ps, depending on the details of the whole structure. The fast carrier transfer is modeled by a diffusion equation which allows one to estimate the quantum mechanical capture time from a two-dimensional vertical QW into a one-dimensional QWR to be <2 ps. 相似文献
14.
15.
Patrizia Marchese Maria Lombardi Maria Elena Mantione Domenico Baccellieri David Ferrara Roberto Chiesa Ottavio Alfieri Chiara Foglieni 《International journal of molecular sciences》2021,22(8)
Atherothrombosis exposes vascular components to blood. Currently, new antithrombotic therapies are emerging. Herein we investigated thrombogenesis of human arteries with/without atherosclerosis, and the interaction of coagulation and vascular components, we and explored the anti-thrombogenic efficacy of blockade of the P2X purinoceptor 7 (P2X7). A confocal blood flow videomicroscopy system was performed on cryosections of internal mammary artery (IMA) or carotid plaque (CPL) determining/localizing platelets and fibrin. Blood from healthy donors elicited thrombi over arterial layers. Confocal microscopy associated thrombus with tissue presence of collagen type I, laminin, fibrin(ogen) and tissue factor (TF). The addition of antibodies blocking TF (aTF) or factor XI (aFXI) to blood significantly reduced fibrin deposition, variable platelet aggregation and aTF + aFXI almost abolished thrombus formation, showing synergy between coagulation pathways. A scarce effect of aTF over sub-endothelial regions, more abundant in tissue TF and bundles of laminin and collagen type I than deep intima, may suggest tissue thrombogenicity as molecular structure-related. Consistently with TF-related vascular function and expression of P2X7, the sections from CPL but not IMA tissue cultures pre-treated with the P2X7 antagonist A740003 demonstrated poor thrombogenesis in flow experiments. These data hint to local targeting studies on P2X7 modulation for atherothrombosis prevention/therapy. 相似文献
16.
Alessandro Casnati Patrizia Minari Andrea Pochini Rocco Ungaro Wilma F. Nijenhuis Feike De Jong David N. Reinhoudt 《Israel journal of chemistry》1992,32(1):79-87
The p-tert-butylcalix[6]arene hexamide 2 and syn-1,3,5–trimethoxy-2,4,6-triamide 4 were synthesized by reaction of α-chloro-N,N-diethylacetamide and the corresponding calix[6]arenes 1 and 3 , respectively. 1H NMR spectroscopy shows that 2 is a mixture of different conformations whereas 4 is fixed in a cone conformation. Extraction experiments, (S-L) and (H2O–CDCl3) with picrate salts, indicate that 2 complexes both alkali metal (1:2 complex) and guanidinium salts (1:1 complex) but 4 complexes only guanidinium (1:1 complex). Incorporated in supported liquid membranes (Accurel® / o-nitrophenyl n-octyl ether) the calixarenes 2 and 4 transport guanidinium salts. The hexamide 2 is a more efficient carrier of guanidinium but the syn-1,3,5-trimethoxy-2,4,6-triamide 4 is much more selective. Both 2 and 4 are sufficiently lipophilic to give membranes that are stable over longer periods (weeks). 相似文献
17.
A. Erb J. -Y. Genoud F. Marti M. Däumling E. Walker R. Flükiger 《Journal of Low Temperature Physics》1996,105(3-4):1023-1028
We report on the absence of the so-called fishtail or peak effect in the magnetisation curves of properly oxygenated high purity (5N) single crystals of YBa2Cu3O7–. As we recently reported [1] high pressure oxygenation procedures are suitable to produce a monotonous dependence of the critical current density with the magnetic field. In this article we report furthermore how to reversibly produce or remove this effect on the same crystal by proper oxygenation methods. Along with the high purity of the samples, — due to crystal growth in non reactive BaZrO3 crucibles —, this proves that at least in pure samples the fishtail effect is due to different oxygenation states and/or oxygen distributions. In less pure samples, however, other sources for this anomaly like metallic impurities can act as an additional source for the fishtail anomaly. 相似文献
18.
19.
Evidence for immunologic processes taking part in the pathogenesis of what until now has been called the "essential" form of EPH gestosis is cited. The name of immunogestosis (IG) is introduced. The data of this preliminary study suggest that regular "inoculation" of the female genital tract with allogeneic spermatozoal histocompatibility antigens reduces the incidence of IG. Information about preconceptional sexual habits and contraceptive measures was obtained from 83 selected primigravid patients. Twenty-eight women had mild to moderate IG (Group B);55 did not (Group A). Women in Group B had had less contact with spermatozoa of partners than did women in Group A. Oral contraceptive consumption was less in Group B than in Group A. Women in Group B were younger than women in Group A. All these differences were statistically significant. A new immunoetiologic hypothesis referring to IG, as well as the theoretic and clinical implications arising from it, are discussed. This hypothesis is based on the assumption that spermatozoal histocompatibility antigens can either induce immunologic tolerance or be responsible for the phenomenon of immunologic enhancement in the maternal immunosystem. As the fetus inherits paternal histocompatibility antigens, it is concluded that pre-existing tolerance (or enhancement) exerts an IG-preventive function in a subsequent pregnancy. 相似文献
20.
K. Marti 《Structural and Multidisciplinary Optimization》1997,13(4):230-243
Yield stresses, allowable stresses, moment capacities (plastic moments), external loadings, manufacturing errors, etc., are not fixed quantities in practice, but must be modelled as random variables with a certain joint probability distribution. In reliability-oriented structural optimization the violation of the random behavioural constraints are evaluated by means of the corresponding probabilityp
s
of survival. Hence, the approximative computation ofp
s
and its sensitivities is of utmost importance. After the consideration of lower bounds ofp
s
based on a selection of certain redundants in the vector of internal forces/bending moments, and the consideration of upper bounds ofp
s
based on an optimizational representation of the yield or safety constraints by a pair of dual linear programs, a conical representation ofp
s
is introduced based on a coneY
o
of admissible pairs of external loads/strength increaments. Approximations ofp
s
can be constructed then by replacing the (finitely generated) coneY
o
by more simple ones, e.g. spherical or ellipsoidal cones. For the direct numerical computation of sensitivities ofp
s
and its bounds or approximations by using e.g. sampling methods or asymptotic expansion techniques based on Laplace integral representation of multiple integrals, exact differentiation formulae — of arbitrary order — forp
s
and its bounds or approximations with respect to deterministic input or design variables are obtained by applying the transformation method/stochastic completion techniques; the derivatives ofp
s
are represented again by certain expectations or multiple integrals. 相似文献