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排序方式: 共有88条查询结果,搜索用时 15 毫秒
1.
Cametti M Nissinen M Dalla Cort A Mandolini L Rissanen K 《Chemical communications (Cambridge, England)》2003,(19):2420-2421
Uranyl-salophen complexes endowed with aromatic side arms behave as very efficient ditopic receptors towards tetralkylammonium halides as a result of a combination of Lewis acid-base and cation-pi interactions. 相似文献
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Trichoderma reesei cellulases and their core domains in the hydrolysis and modification of chemical pulp 总被引:2,自引:0,他引:2
A. Suurnäkki M. Tenkanen M. Siika-aho M.-L. Niku-Paavola L. Viikari J. Buchert 《Cellulose (London, England)》2000,7(2):189-209
The action of monocomponent Trichoderma reesei endoglucanases (EG I, EG II; EC 3.2.1.4) and cellobiohydrolases (CBH I, CBH II; EC 3.2.1.91) and their core proteins was compared using isolated celluloses and bleached chemical pulp. The presence of cellulose binding domain (CBD) in the intact enzymes did not affect their action against soluble substrates. In the case of insoluble isolated celluloses and the chemical pulp the presence of CBD enhanced the enzymatic hydrolysis of cellulose. The effect of CBD was more pronounced in the cellobiohydrolases, hydrolysing mainly crystalline cellulose, than in the endoglucanases which were more efficient in hydrolysing amorphous cellulose. The pulp properties measured, that is, viscosity and strength after PFI refining, were equally affected by the treatment with intact enzymes and corresponding core proteins, suggesting that the presence of CBD in intact cellulases affects mainly the cellulose hydrolysis level and less the mode of action of T. reesei cellulases in pulp. The better beatability of the bleached chemical pulp treated with intact endoglucanases than that treated with the corresponding core proteins suggests that the presence of CBD in endoglucanases could, however, result in beneficial effects on pulp properties. 相似文献
4.
Cametti M Ilander L Valkonen A Nieger M Nissinen M Nauha E Rissanen K 《Inorganic chemistry》2010,49(24):11473-11484
Ditopic salophen-UO(2) receptors 1-4 and 7 co-crystallize with tetramethylammonium (TMA) chloride and fluoride salts producing good quality crystals amenable for X-ray diffraction characterization. The arrangement of the receptor and salt units in the crystal lattice is such that tetrameric ball-shaped assemblies are formed, where an inner cluster of four TMA cations are surrounded by an outer shell of four UO(2)-bound anions. These elaborate architectures, which occur in all cases, regardless of a certain degree of structural modification on the receptors, lead to lattices that belong to non-centrosymmetric (NCS) space groups. Interestingly, the tetragonal symmetry of the tetrameric ball-shaped assemblies is either retained (I4?) or lost (R3c and I4?3d) at the lattice level, without compromising the NCS nature of the crystal lattices. The principal X-ray investigation on TMAX (X = Cl/F) co-crystals, that is, 1-(TMA)Cl, 2-(TMA)Cl, 3-(TMA)Cl, 4-(TMA)Cl, 7-(TMA)Cl, and 7-(TMA)F, is accompanied by NMR and electrospray ionization (ESI) mass spectrometry studies to gather additional insight on the modality of formation of the solid state structures observed. The important role of cation-π interactions in the receptor-salt recognition process is renewed and strengthened by comparison with NMR titration data with a novel reference compound, the salophen-UO(2) complex 8. Given the importance of NCS and polar crystalline solids in the development of functional materials, this study shows that this property can be introduced into elaborate host-guest systems, as those which assemble in the architectures described here, thus expanding its field of applicability. 相似文献
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Tiia‐Riikka Tero Dr. Kirsi Salorinne Dr. Heli Lehtivuori Prof. Janne A. Ihalainen Prof. Maija Nissinen 《化学:亚洲杂志》2014,9(7):1860-1867
An unexpected and previously unknown resorcinarene mono‐crown with a fused benzofuran moiety in its macrocyclic core was obtained as a byproduct from a bridging reaction of tetramethoxy resorcinarene with tetraethylene glycol ditosylate. The formation of the fused benzofuran moiety in the resorcinarene macrocycle resulted in a unique rigid and puckered boat conformation, as shown by XRD studies in the solid state. Modification of the macrocycle was also observed to affect the photophysical properties in solution by enhancing the fluorescence brightness compared with a conventional resorcinarene macrocycle. The fluorescent properties enabled unique detection of structural features, that is, the rigid boat conformation with the conjugated benzofuran system and the more flexible crown bridge part, in solution. 相似文献
7.
Kalnina I Klimkane L Kirilova E Toma MM Kizane G Meirovics I 《Journal of fluorescence》2007,17(6):619-625
The fluorescent probe-aminoderivative of benzanthrone, ABM (developed at Riga Technical University, Riga, Latvia) was used
to characterize the membranes of lymphocytes of cancer patients: 46 patients with gastrointestinal diseases, 13 patients having
different primary localizations with massive metastases and intoxication. Patients were divided into three groups: (1) with
decreased fluorescence intensity, (2) normal fluorescence intensity, (3) increased fluorescence intensity. The lymphocytes
distribution among subsets differed between groups, in correspondence to the level of florescence intensity. Surgical treatment
affected the main immunological parameters and elevated the functional activity of lymphocytes. In the advanced tumors group,
fluorescence intensity correlates with the survival rate. Results suggest that determination of lymphocytes functional activity
by ABM can aid evaluation of the immune status in cancer patients. 相似文献
8.
[structure: see text] Sterically hindered tetraaminomethylated resorcarenes form inclusion complexes in CDCl(3) with acetonitrile and acetaldehyde, which are kinetically stable on the NMR time scale at 233 K. 相似文献
9.
Maija Pitknen 《Magnetic resonance in chemistry : MRC》1984,22(7):434-438
The average conformations of methyl esters of some aliphatic erythro- and threo-dichlorocarboxylic acids in dilute carbon tetrachloride solutions have been determined from the vicinal proton–proton coupling constants and 1H NMR shifts. The 13C shift differences between the erythro and threo forms are compared and discussed with regard to the differences in the average conformations. 相似文献
10.