排序方式: 共有46条查询结果,搜索用时 31 毫秒
41.
Sandip N.Gavade Ravi S.Balaskar Madhav S.Mane Pramod N.Pabrekar Murlidhar S.Shingare Dhananjay V.Mane 《中国化学快报》2011,22(6):675-678
The coupling reaction of phenylurea with different functionalized aryl halides in the presence of air stable CuI,N,N-dimethylethylenediamine as a ligand,and K3PO4 as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields.This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligands. 相似文献
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The waveguide-length sensitivity on modified spontaneous emission in finite-size planar photonic crystal (PC) waveguides is investigated by numerically computing the exact Purcell (enhanced emission) factor. An unusual dependence on the number of waveguide unit cells and on the waveguide facet truncation is found, allowing one to nanoengineer large Purcell factors in excess of several hundred. Besides having important applications for single-photon sources, these results offer physical insight into the nature of light-matter interactions in miniaturized finite-size PC waveguides, where periodic Bloch-wave analysis breaks down. 相似文献
44.
A series of novel cyclic urea molecules 5,6-dihydroxy-1,3-diazepane-2,4,7-trione as HIV-1 protease inhibitors were designed
using computational techniques. The designed molecules were compared with the known cyclic urea molecules by performing docking
studies, calculating their ADME (Absorption, Distribution, Metabolism, and Excretion) properties and protein ligand interaction
energy. These novel molecules were designed by substituting the P
1/P′
1 positions (4
th
and 7
th
position of 1, 3-diazepan-2-one) with double bonded oxygens. This reduces the molecular weight and increases the bioavailability,
indicating better ADME properties. The docking studies showed good binding affinity towards HIV-1 protease. The biological
activity of these inhibitors were predicted by a model equation generated by the regression analysis between biological activity
(log 1/K
i
) of known inhibitors and their protein ligand interaction energy. The synthetic studies are in progress.
相似文献
45.
Helane?MS?Costa Augusto?CV?Freitas Júnior Ian?PG?Amaral Izaura?Y?Hirata Patrícia?MG?Paiva Luiz?B?CarvalhoJr Vitor?Oliveira Ranilson?S?BezerraEmail author 《Chemistry Central journal》2013,7(1):166
Background
Over the past decades, the economic development and world population growth has led to increased for food demand. Increasing the fish production is considered one of the alternatives to meet the increased food demand, but the processing of fish leads to by-products such as skin, bones and viscera, a source of environmental contamination. Fish viscera have been reported as an important source of digestive proteases with interesting characteristics for biotechnological processes. Thus, the aim of this study was to purify and to characterize a trypsin from the processing by-products of crevalle jack (Caranx hippos) fish.Results
A 27.5 kDa trypsin with N-terminal amino acid sequence IVGGFECTPHVFAYQ was easily purified from the pyloric caeca of the crevalle jack. Its physicochemical and kinetic properties were evaluated using N-α-benzoyl-DL-arginine-p-nitroanilide (BApNA) as substrate. In addition, the effects of various metal ions and specific protease inhibitors on trypsin activity were determined. Optimum pH and temperature were 8.0 and 50°C, respectively. After incubation at 50°C for 30 min the enzyme lost only 20% of its activity. K m , kcat, and k cat /K m values using BApNA as substrate were 0.689 mM, 6.9 s-1, and 10 s-1 mM-1, respectively. High inhibition of trypsin activity was observed after incubation with Cd2+, Al3+, Zn2+, Cu2+, Pb2+, and Hg2+ at 1 mM, revealing high sensitivity of the enzyme to metal ions.Conclusions
Extraction of a thermostable trypsin from by-products of the fishery industry confirms the potential of these materials as an alternative source of these biomolecules. Furthermore, the results suggest that this trypsin-like enzyme presents interesting biotechnological properties for industrial applications.46.
Árpád Bihari Zoltán Dezső Tibor Bujtás László Manga András Lencsés Péter Dombóvári 《Isotopes in environmental and health studies》2014,50(1):94-102
Fission products, especially 131I, 134Cs and 137Cs, from the damaged Fukushima Dai-ichi nuclear power plant (NPP) were detected in many places worldwide shortly after the accident caused by natural disaster. To observe the spatial and temporal variation of these isotopes in Hungary, aerosol samples were collected at five locations from late March to early May 2011: Institute of Nuclear Research, Hungarian Academy of Sciences (ATOMKI, Debrecen, East Hungary), Paks NPP (Paks, South-Central Hungary) as well as at the vicinity of Aggtelek (Northeast Hungary), Tapolca (West Hungary) and Bátaapáti (Southwest Hungary) settlements. In addition to the aerosol samples, dry/wet fallout samples were collected at ATOMKI, and airborne elemental iodine and organic iodide samples were collected at Paks NPP. The peak in the activity concentration of airborne 131I was observed around 30 March (1–3 mBq m?3 both in aerosol samples and gaseous iodine traps) with a slow decline afterwards. Aerosol samples of several hundred cubic metres of air showed 134Cs and 137Cs in detectable amounts along with 131I. The decay-corrected inventory of 131I fallout at ATOMKI was 2.1±0.1 Bq m?2 at maximum in the observation period. Dose-rate contribution calculations show that the radiological impact of this event at Hungarian locations was of no considerable concern. 相似文献