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141.
Danilo Annibali Gerhard Ecker Wilhelm Fleischhacker Thomas Helml Wolfgang Holzer Christian R. Noe 《Monatshefte für Chemie / Chemical Monthly》2000,131(4):375-382
Summary. The synthesis of 2,3-disubstituted 2,3-dihydrobenzofuran diastereomers is described. The key step in the reaction sequence
is the chemoselective reduction of a tert. alcohole with tert.-butylamine-borane/AlCl3. The relative configuration of the substituents on the dihydrofurane moiety was assigned via NMR spectroscopy.
Received September 7, 1999. Accepted November 9, 1999 相似文献
142.
Eduardo A. Soto-Bustamante Rafael Vergara-Toloza Danilo Salda o-Hurtado Patricio Navarrete-Encina 《Liquid crystals》2003,30(5):585-589
The synthesis and measurement of thermodynamic properties of six methacrylate-based polymers were undertaken to observe the relationship between structural aliphatic features and mesophase properties. X-ray measurements on some of the polymers investigated show, as expected, the existence of bilayered smectic phases SmC 2 and SmA d . Taking into account our previous results, an interesting trend in the tilt angle was found that might be related to the difference in alkyl chain substitution. 相似文献
143.
144.
145.
Danilo Villarroel 《Annals of Physics》1975,89(1):241-253
We analyse some redefinitions of the energy-momentum tensor of Classical Electrodynamics. Usually it has been considered as a necessary and sufficient criterion for redefining the energy-momentum tensor that the new tensor yields the “true” equation of motion of the electron, that is, the Lorentz-Dirac equation. We show that such a property is not sufficient. In fact, we study two specific examples in which the redefined energy momentum tensor yields a Lorentz-Dirac equation. However, in both cases the corresponding rate of emission associated to them is different to the well-known Larmor rate. 相似文献
146.
Yang GY Hanack M Lee YW Chen Y Lee MK Dini D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(12):2758-2762
The fluorine-containing metal naphthalocyanines [F16NcGaCl] (7) and [(F16NcGa)2O] (8), which represent the first examples of peripherally fluorine substituted naphthalocyanines, were synthesized, and the nonlinear optical transmission was studied. Peripheral substitution by fluorine atoms enhances the solubility and photostability of the naphthalocyanines. In particular, for the axially mu-oxo-bridged naphthalocyanine dimer 8, practically no aggregation was observed in organic solvents and it has proved to be an efficient optical limiter when irradiated with laser light pulses at the wavelength of 532 nm, with pulse duration of 5 ns and repetition rate of 20 Hz. 相似文献
147.
Wittke S Fliser D Haubitz M Bartel S Krebs R Hausadel F Hillmann M Golovko I Koester P Haller H Kaiser T Mischak H Weissinger EM 《Journal of chromatography. A》2003,1013(1-2):173-181
The on-line coupling of capillary electrophoresis (CE) with electrospray-time-of-flight mass spectrometry (MS) has been used to obtain patterns of peptides and proteins present in the urine of healthy human individuals. This led to the establishment of a "normal urine polypeptide pattern", consisting of 247 polypeptides, each of which was found in more than 50% of healthy individuals. Applying CE-MS to the analysis of urine of patients with kidney disease revealed differences in polypeptide pattern. Twenty-seven polypeptides were exclusively found in samples of patients. Another 13, present in controls, were missing. These data indicate that CE-MS can be applied as powerful tool in clinical diagnostics. 相似文献
148.
Capillary electrophoresis coupled to mass spectrometry to establish polypeptide patterns in dialysis fluids 总被引:1,自引:0,他引:1
Kaiser T Hermann A Kielstein JT Wittke S Bartel S Krebs R Hausadel F Hillmann M Golovko I Koester P Haller H Weissinger EM Fliser D Mischak H 《Journal of chromatography. A》2003,1013(1-2):157-171
Combination of capillary electrophoresis with mass spectrometry (CE-MS) allows generation of polypeptide patterns of body fluids. In a single CE-MS (45 min) run more than 600 polypeptides were analyzed in hemodialysis fluids obtained with different membranes (high-flux/low-flux). Larger polypeptides (M(r) > 10 000) were almost exclusively present in high-flux dialysates only, while in low-flux dialysates additional small polypeptides were detected. Comparison to the normal urine pattern yielded a surprisingly low consensus: a number of polypeptides present in urine were missing. We established a fast and sensitive technique, easily applicable to the monitoring of different modalities of dialyzers. 相似文献
149.
Nostro PL Corrieri D Ceccato M Baglioni P 《Journal of colloid and interface science》2001,236(2):270-281
Tencel is a relatively new fabric, obtained from wood pulp, that looks like natural cotton. In order to be suitable for commercial purposes, Tencel must be processed to improve its qualities. In this paper we report our studies on the enzymatic defibrillation of Tencel, in which we checked the different behavior of the same set of enzymes dispersed in pure water and in a microemulsion system. Surface properties, such as scanning electron microscopy, contact angle, porosimetry, breaking load, and thickness, were determined, in order to monitor the surface modification of the fabric upon enzymatic defibrillation, and indicate that the process is more efficient and less damaging when carried out in the microemulsion medium. Furthermore, we chemically modified Tencel by attaching fluorinated chains to the fabric surface. Surface properties show that fluorination of Tencel leads to a high degree of water- and oil-repellency in the fabric. Copyright 2001 Academic Press. 相似文献
150.
Cheng G Romero D Fraser GT Hight Walker AR 《Langmuir : the ACS journal of surfaces and colloids》2005,21(26):12055-12059
Under the influence of a 0.05 T magnetic field, 15-nm diameter cobalt nanoparticles covered with surfactants in a colloidal solution assemble into highly constrained linear chains along the direction of the magnetic field. The magnetic-field-induced (MFI) chains become floppy after removal of the field, folding into three-dimensional (3D) coiled structures upon gentle agitation. The 3D structures are broken into smaller units with vigorous agitation. The nanoparticles redisperse into the solvent upon ultrasonic agitation. Optical microscopy and transmission electron microscopy (TEM) are used to characterize the morphologies of the nanoparticle assemblies at various stages of this reversible process. The hysteresis loops and zero-field cooled/field cooled (ZFC/FC) curves reveal the interparticle coupling in the assemblies. MFI assembly provides a powerful tool to manipulate magnetic nanoparticles. 相似文献