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861.
Ohne ZusammenfassungHerrn Prof. Dr. Hans Meyer, dem ich auch die Anregung zu dieser kleinen Untersuchung danke, bin ich für sein freundliches Entgegenkommen verpflichtet. 相似文献
862.
863.
864.
Among the many interesting results of their 1958 paper, G. Pólya and I. J. Schoenberg studied the de la Vallée Poussin means
of analytic functions. These are polynomial approximations of a given analytic function on the unit disk obtained by taking
Hadamard products of the functionf with certain polynomialsV
n
(z), wheren is the degree of the polynomial. The polynomial approximationsV
n
*f converge locally uniformly tof asn→∞. In this paper, we define a subordination chainV
λ
(z),γ>0, |z|<1, of convex mappings of the disk that for integer values is the same as the previously definedV
n
(z). Iff is a conformal mapping of the diskD onto a convex domain, thenV
λ
*f→f locally uniformly as λ→∞, and in fact
when λ2 > λ1. We also consider Hadamard products of theV
λ with complex-valued harmonic mappings of the disk.
This work was supported by the Volkswagen Stiftung (RiP-program at Oberwolfach). S. R. received partial support also from
INTAS (Project 99-00089) and the German-Israeli Foundation (grant G-643-117.6/1999). 相似文献
865.
Owen SJ Meier FS Brombacher S Volmer DA 《Rapid communications in mass spectrometry : RCM》2003,17(21):2439-2449
Spot size reduction and increased detection sensitivity in matrix-assisted laser desorption/ionisation (MALDI) of small molecules are accomplished by using an inexpensive and removable hydrophobic coating for MALDI targets, based on 3M Scotch Gard surface treatment. Several variations in sample preparation were explored, such as surface coating technique, identity of the matrix, solvent composition, and the type of metal support plate used. These were investigated on both uncoated and coated surfaces and their impact on spot size, crystal coverage, and sensitivity is presented here. Additionally, crystallisation behaviour obtained on coated plates is compared with that on uncoated plates using scanning electron microscope analysis. To demonstrate the potential of the new coating technique, erythromycin A and valinomycin are studied to determine the increase in detection sensitivity of coated plates in comparison to uncoated plates, and to reveal the suitability of the plates for application in combined high-performance liquid chromatography/MALDI (HPLC/MALDI), where widely varying solvent compositions and droplet volumes are observed. It is shown that enhancements in detection sensitivities correlate very well with the achieved spot size reduction. The versatility of the coated plates is also exhibited by the ease of removing the surface layer, after which the plates can be rigorously cleaned without worry about damaging the hydrophobic surface, followed by a quick reapplication of new hydrophobic coating material. This makes the non-polar coating superior to more expensive commercial hydrophobic-coated targets, which are much more delicate to clean. Furthermore, cleaning and reapplication eliminate potential carry-over effects and the easy application procedure also makes the fabrication of inexpensive, disposable MALDI targets readily possible. 相似文献
866.
Braun M Atalick S Guldi DM Lanig H Brettreich M Burghardt S Hatzimarinaki M Ravanelli E Prato M van Eldik R Hirsch A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(16):3867-3875
Two dendritic fullerene (DF) monoadducts, 2 and 3, which can carry up to 9 and 18 negative charges, respectively, were examined with respect to electrostatic complexation with Cytochrome c (Cytc). To facilitate comprehensive photophysical investigations, the zinc analogue of Cytc (ZnCytc) was prepared according to a novel, modified procedure. The association of ZnCytc and DF, and consequential photoinduced electron transfer within ZnCytc-DF from the photoexcited protein to the fullerene, was proven by fluorescence spectroscopy and transient absorption spectroscopy. These findings were also supported by circular dichroism as well as by extensive molecular dynamics (MD) simulations. 相似文献
867.
Let C be a simply connected domain, 0, and let n,nN, be the set of all polynomials of degree at mostn. By n() we denote the subset of polynomials p n withp(0)=0 andp(D), whereD stands for the unit disk {z: |z|<1}, and=" by=">1},>we denote the maximal range of these polynomials. Letf be a conformal mapping fromD onto ,f(0)=0. The main theme of this note is to relate n (or some important aspects of it) to the imagesf
s
(D), wheref
s
(z):=f[(1–s)z], 0s<1. for=" instance=" we=" prove=" the=" existence=" of=" a=" universal=">1.>c
0 such that, forn2c
0, 相似文献
868.
869.
Summary Sterol 14α-demethylase (CYP51) is one of the known major targets for azole antifungals. Therapeutic side effects of these antifungals are based on interactions of the azoles with the human analogue enzyme. This study describes for the first time a comparison of a human CYP51 (HU-CYP51) homology model with a homology model of the fungal CYP51 of Candida albicans (CA-CYP51). Both models are constructed by using the crystal structure of Mycobacterium tuberculosis MT-CYP51 (PDB code: 1EA1).The binding mode of the azole ketoconazole is investigated in molecular dynamics simulations with the GROMACS force field. The usage of special parameters for the iron azole complex binding is necessary to obtain the correct complex geometry in the active site of the enzyme models. Based on the dynamics simulations it is possible to explain the enantioselectivity of the human enzyme and also to predict the binding mode of the isomers of ketoconazole in the active site of the fungal model. 相似文献
870.
Stephan Enthaler 《Journal of organometallic chemistry》2006,691(22):4652-4659
Novel ruthenium carbene complexes have been in situ generated and tested for the transfer hydrogenation of ketones. Applying Ru(cod)(methylallyl)2 in the presence of imidazolium salts in 2-propanol and sodium-2-propanolate as base, turnover frequencies up to 346 h−1 have been obtained for reduction of acetophenone. A comparative study involving ruthenium carbene and ruthenium phosphine complexes demonstrated the higher activity of ruthenium carbene complexes. 相似文献