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1.
We present an update of Garland's work on the cohomology of certain groups, construct a class of groups many of which satisfy Kazhdan's Property (T) and show that properly discontinuous and cocompact groups of automorphisms of (4,4) or (6,3)-complexes do not satisfy Property (T). Submitted: September 1996, final version: March 1997  相似文献   
2.
Summary Endohedral and exohedral metallofullerenes, including metal-doped fullerenes, organometallic fullerenes and fullerene metal complexes, are described in the context of their syntheses and properties.  相似文献   
3.
The surface of a germanium internal reflectance element (IRE) was modified to bind 6X-histidine (his)-tagged biomolecules. The step-by-step surface modification was monitored via single-pass attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT-IR). Initially an adlayer of 7-octenyltrimethoxysilane (7-OTMS) was formed on the Ge crystal through the surface hydroxyl groups, which were produced via ozonolysis of the Ge surface. The vinyl moiety of 7-OTMS was oxidized to a carboxylic acid, which was activated by 1,1'-carbonydiimidazole (CDI) to produce a labile imidazole. The labile imidazole that resulted from the CDI coupling was then displaced by the primary amine of nitrilotriacetic acid (NTA). Nickel sulfate was added to the system, and it coordinated with the three carbonyl groups and the nitrogen on NTA, thus leaving the ability of Ni to coordinate with two adjacent histidine residues. Binding of his-tagged biotin to nickel nitrilotriacetic acid (Ni-NTA) was observed by ATR-FT-IR spectroscopy. The surface modification method presented in this paper had minimal nonspecific binding, the Ni-NTA surface was reusable if stored properly, and complete removal of the organic surface was achievable.  相似文献   
4.
Synthesis of N-and C-substituted derivatives of benzo[h][1,6]naphthyridine, bearing 2-hydroxyethyl group has been made by quaternization reaction and by condensation of corresponding methylbenzonaphthyridines with formaldehyde. For six derivatives of isomeric benzo[c][1,5]-, benzo[h][1,6]-, and benzo[f][1,7]naphthyridines the 13C NMR spectra are discussed. For ten compounds the geometry was optimized with the AM1 and, in one case also with the ab initio 6–31G method; their effective charge values have also been calculated.  相似文献   
5.
Summary The substitution of phosphine in the [RhCl(COD)(phosphine)] complex (1), where phosphine is PPh3 or 1/2 BPS-2 [bis(diphenylphosphinoethyl)tetramethyldisiloxane] and COD is cycloocta-1,5-diene, by 1-hexene is a two-step reversible reaction. All individual rate constants and equilibrium constants were determined spectrophotometrically and associative mechanism occurring via the formation of five-coordinated [RhCl(COD)(phosphine)(1-hexene)] (2) was inferred. The rate-determining step changes from the first- to the second-one as the concentration of 1-hexene increases. An excess of phosphine shifts the equilibrium towards complex (2).  相似文献   
6.
The reaction of [Ti4(OMe)14Cl2] (1) with an excess of AlMe3 gave the cocrystallite [Ti2(mu-OMe)2(mu-Cl)Cl3(thf)3].[Ti2(mu-OMe)3Cl3(thf)3] (2.3) species in a 1:1 ratio. Similar to 2, [Ti2(mu-OEt)2(mu-Cl)Cl3-(thf)3] (4) was obtained in the reaction of an equimolar mixture of TiCl4 and Ti(OEt)4 with Al/AlMe3. The short distance [2.543(1)av A in 2.3 and 2.599(1) A in 4] between "Ti(+3)" atoms, their diamagnetism, and ELF analysis indicate the presence of a Ti-Ti bond.  相似文献   
7.
We study weakly order preserving circle maps with a flat interval, which are differentiable even on the boundary of the flat interval. We obtain estimates on the Lebesgue measure and the Hausdorff dimension of the non-wandering set. Also, a sharp transition is found from degenerate geometry to bounded geometry, depending on the degree of the singularities at the boundary of the flat interval.Partially supported by KBN grant Iteracje i Fraktale #210909101.  相似文献   
8.
A one-step solid-phase extraction procedure, based on a new silica gel adsorbent modified with cholesterol groups, has been investigated for measurement of cotinine in urine. Cotinine is the main metabolite of nicotine in the human body and is analyzed as a biomarker for assessment of direct or passive exposure to tobacco smoke. New cholesterol-modified adsorbents have been obtained by chemical modification of silica gel of different porosity with cholesterol ligands. Although recovery by this extraction procedure were optimum over a relatively broad range of sample pH (3.1–8.0), analytical conditions such as sample loading, washing and elution conditions, concentration of cotinine to be extracted, and the type of adsorbent used for extraction were found to affect the efficiency of the procedure and had to be controlled for optimum recovery. When these conditions were controlled, recovery of cotinine from spiked human urine was reproducible and depended on compound ionization. Quantitative analysis of cotinine was performed by reversed-phase high-performance liquid chromatography with UV detection. Presented at: Conference of the Hyphenation of Liquid Chromatography–Nuclear Magnetic Resonance Spectroscopy, Liquid Chromatography–Mass Spectrometry and Related Topics, Tuebingen, Germany, March 25–29, 2006.  相似文献   
9.
Summary Trisubstituted silanes, HSiR3–n X n (R = Me, Et, Pr or Bu; X = Cl, OEt or Ph; and n = 0–3) readily undergo oxidative addition to complex [RhCl(cod)PPh3] (where cod = cycloocta-1,5-diene).The quantitative correlation between rate constants, k 1, of the reaction, followed spectrophotometrically at 20 °C in benzene solutions, and the structure of tri-substituted silanes represented by stereoelectronic parameters , and E of the substituents, was established: logk 1 = a + b + c + dE. The reaction rate is accelerated by electron-withdrawing substituents at silicon and retarded by the bulk and pd donation of nonalkyl substituents.Author to whom all correspondence should be directed.  相似文献   
10.
The combustibilities ofcis-1,4-polyisoprene and its peroxide and sulphur vulcanizates have been investigated by means of the oxygen index method. The temperature distribution in the sample and the molecular weight of the liquid products formed as a result of elastomer destruction in the combustion zone have been measured. It has been found that the combustibility ofcis- 1,4-polyisoprene diminishes as its cross-link density increases. This effect is much stronger for sulphur than for peroxide vulcanizates. The investigations lead to the conclusion that a mechanism of network degradation and volatile sulphur compounds penetrating to the flame are responsible for this difference.
Zusammenfassung Die Brennbarkeit des unvernetztencis-1,4-Polyisoprens und seiner Peroxid- und Schwefelvulkanisate wurde mit der Sauerstoffindexmethode untersucht. Messungen der Temperaturverteilung im Prüfling wurden ebenfalls ausgeführt und das Molekulargewicht der infolge der Zersetzung der Elastomere in der Verbrennungszone entstehenden flüssigen Produkte mit der Methode der dynamischen Osmometrie bestimmt. Es wurde festgestellt, daß die Brennbarkeit des cis-1,4-Polyisoprens mit zunehmender Vernetzungsdichte abnimmt, und zwar viel ausgeprägter im Falle der Schwefel- als im Falle der Peroxidvulkanisate. Es wurde gefolgert, daß flüchtige, in die Flamme gelangende Schwefelverbindungen als Verbrennungsinhibitoren wirken.

-1,4- . , . , -1,4- . . , .
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