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71.
The title compound, a naturally-occurring amino acid found in virotoxins, competitively inhibits bovine β-D-glucuronidase but does not affect other glycosidases. 相似文献
72.
Albert H. Beth Ray C. Perkins Sindhaghatta D. Venkataramu Donald E. Pearson Charles R. Park Jane H. Park Larry R. Dalton 《Chemical physics letters》1980,69(1):24-28
The spin label, perdeuterio-N-(1-oxy 1-2,2,6,6-tetramenthyl-4-piperidinyl)maleimide (DMSL) was synthesized and its EPR and saturation transfer EPR spectra were compared to those of the hydrogen analogue, HMSL- The labels were studied as freely tumbling entities and also bound to bovine serum albumin (BSA). Significant gains in spectral resolution and detectability were observed for DMSL relative to HMSL. 相似文献
73.
Tse KY Nichols BM Yang W Butler JE Russell JN Hamers RJ 《The journal of physical chemistry. B》2005,109(17):8523-8532
Recent studies have shown that semiconductor surfaces such as silicon and diamond can be functionalized with organic monolayers, and that these monolayer films can be used to tether biomolecules such as DNA to the surfaces. Electrical measurements of these interfaces show a change in response to DNA hybridization and other biological binding processes, but the fundamental nature of the electrical signal transduction has remained unclear. We have explored the electrical impedance of polycrystalline and single-crystal diamond surfaces modified with an organic monolayer produced by photochemical reaction of diamond with 1-dodecene. Our results show that, by measuring the impedance as a function of frequency and potential, it is possible to dissect the complex interfacial structure into frequency ranges where the total impedance is controlled by the molecular monolayer, by the diamond space-charge region, and by the electrolyte. The results have implications for understanding the ability to use molecularly modified semiconductor surfaces for applications such as chemical and biological sensing. 相似文献
74.
Daniel R. Drodge Beth Mortimer Chris Holland Clive R. Siviour 《Journal of the mechanics and physics of solids》2012,60(10):1710-1721
A revision of a classic transverse fibre impact technique is presented, as applied to the problem of obtaining the high strain-rate constitutive behaviour of commercial Bombyx mori silk. Medium tenacity nylon was also studied. Two approaches are presented: firstly a fixed pre-stress, varied impact velocity method that derives stress–strain behaviour by inverse fit; and secondly a fixed impact velocity, varied pre-stress approach, assuming basic elastic jump conditions to obtain a locus of post-impact states. The post-impact stress–strain states obtained using the two approaches converge for silk but diverge for nylon. This we attribute to silk's fine structure being able to homogenise energy dissipation at static and dynamic deformation rates. However, the coarser microstructure of nylon results in a different loading path dependence, thus divergence in the two approaches. It was also noted that silk exhibited a comparatively stable level of impact energy absorption under varying pre-stress, when compared to nylon. 相似文献
75.
76.
R. A. Huggins 《Ionics》1999,5(3-4):269-274
A general electrical circuit is described whose properties are analogous to those of fuel cells and batteries. It is shown
how this equivalent circuit model can show the influence of changes in material parameters upon the output of such physical
systems. As an example, the significance of the transference numbers of minority electronic and ionic charge carriers in the
electrolyte on the output voltage of fuel cells and batteries is readily seen.
Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999. 相似文献
77.
78.
Patrick?Shahgaldian Anthony?W.?ColemanEmail author Beth?Rather Michael?J.?Zaworotko 《Journal of inclusion phenomena and macrocyclic chemistry》2005,52(3-4):241-245
The crystal structure of para-octanoylcalix-[4]-arene·2 tetrahydrofuran complex reveals double inclusion of the guest molecules, one deep in the aromatic cavity and the other held in a four-fingered molecular hand formed by the aliphatic chains, the inclusion changes the molecular packing from a bilayer system in the absence of guest, to a head-to-tail antiparallel chain packing.This revised version was published online in July 2005 with a corrected issue number. 相似文献
79.
Knapp-Reed B Mahandru GM Montgomery J 《Journal of the American Chemical Society》2005,127(38):13156-13157
Ni-catalyzed reductive macrocyclizations of ynals are reported. Disubstituted alkynes afford either endocyclic or exocyclic allylic alcohols depending on the ligand. Phosphine ligands favor the formation of endocyclic olefins, whereas N-heterocyclic carbene ligands favor the formation of exocyclic olefins. Terminal alkynes provide 1,2-disubstituted olefins with N-heterocyclic carbene ligands. 相似文献
80.
The molecular structures and E ? Z photoisomerization reactions of methyl urocanate and several urocanamides were investigated. All of the Z isomers possess intramolecular hydrogen bonds. The intramolecular hydrogen bonds may influence the efficiency of photoisomerization but do not totally inhibit its occurrence. The relative energies of the electronic absorption of the E and Z isomers depends on the mode of hydrogen bonding and are accurately predicted in the case of methyl urocanate using INDO/S-CI calculations. The solvent dependence of the absorption spectra of methyl urocanate can be related to the effects of inter- and intramolecular hydrogen bonding. 相似文献