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71.
Mohd Nasir M. N. Al-Mansoori M. H. Abdul Rashid H. A. Choudhury P. K. Yusoff Z. 《Laser Physics》2008,18(4):446-448
In this paper, we demonstrate a multiwavelength Brillouin erbium fiber laser in a Fabry-Perot cavity. The design utilized a bidirectional oscillation provided by a fiber Bragg grating filter and a fiber loop mirror at each end of the laser cavity. A stable operation of 25 Brillouin-Stokes lines was obtained at around a 1559-nm band. 相似文献
72.
Chaitanya A. K. Koppisetty Waqas Nasir Francesco Strino Gustaf E. Rydell Göran Larson Per-Georg Nyholm 《Journal of computer-aided molecular design》2010,24(5):423-431
Norovirus strains are known to cause recurring epidemics of winter vomiting disease. The crystal structure of the capsid protein
of VA387, a representative of the clinically important GII.4 genocluster, was recently solved in complex with histo-blood
group A- and B-trisaccharides. However, the VA387 strain is known to bind also to other natural carbohydrates for which detailed
structural information of the complexes is not available. In this study we have computationally explored the fit of the VA387
with a set of naturally occurring carbohydrate ligands containing a terminal α1,2-linked fucose. MD simulations both with
explicit and implicit solvent models indicate that type 1 and 3 extensions of the ABO-determinant including ALeb and BLeb pentasaccharides can be well accommodated in the site. Scoring with Glide XP indicates that the downstream extensions of
the ABO-determinants give an increase in binding strength, although the α1,2-linked fucose is the single strongest interacting
residue. An error was discovered in the geometry of the GalNAc-Gal moiety of the published crystal structure of the A-trisaccharide/VA387
complex. The present modeling of the complexes with histo-blood group A-active structures shows some contacts which provide
insight into mutational data, explaining the involvement of I389 and Q331. Our results can be applicable in structure-based
design of adhesion inhibitors of noroviruses. 相似文献
73.
A new and convenient spectrophotometric method for the estimation of vanadium(IV) with NTA is described. The minimum ratio of metal ion to ligand, working pH, wavelength for maximum absorbance of the complex ion, and the effect of various cations and anions are described. The complex ion obeys Beer's law in the concentration range 1–32 mmol/liter of the vanadium(IV) ion. It is observed that iron(II), cobalt(II), nickel(II), copper(II), and oxidizing anions such as chromate and nitrite interfere in this determination, whereas managanese(II), chromium(III), iron(III), and anions like nitrate, chloride, bromide, iodide, thiocyanate, sulfate, and sulfite do not have any effect. Excessive amounts of acetate, phosphate, oxalate, tartrate and thiosulfate must also be avoided in this determination. Anions and cations which interfere in the determination of vanadium(IV) by NTA should not be present in the system. 相似文献
74.
The cyclization of β-ketosulfone, β-ketonitrile and β-ketophosphonate dianions with 1,1-diacetylcyclopropane afforded 1-hydroxyspiro[5.2]cyclooct-4-en-3-ones, which were transformed, by reaction with tetrabutylammonium halides, into functionalized phenols containing a remote halide function. 相似文献
75.
76.
Nasir Ahmad Nasir Iqbal Christy Munir 《Monatshefte für Chemie / Chemical Monthly》2000,131(10):1067-1072
Summary. The synthesis and characterization of homobimetallic complexes of VO(IV), Cr(II), Co(II), Ni(II), and Cu(II) with the chiral
Schiff base (1S,2S)-N,N-1,2-Diphenylethylene-bis-(5-imino-1-phenyl-1,3-hexa-nedione) is reported. The metal ions occupy both compartments of the ligand; water molecules fill
the coordination spheres to provide an octahedral environment around the central atoms. The antibacterial activity of both
mono- and bimetallic complexes against a number of Gram-positive as well as Gram-negative bacteria has been tested and is discussed.
Received March 28, 2000. Accepted May 26, 2000 相似文献
77.
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79.
Ring-opening reactions of oxetanes yield important functionalized products depending upon the nature of nucleophiles as well as substitution pattern on the oxetane ring. Ring opening of oxetanes can be carried out under a variety of reaction conditions. In this review article, an up-to-date overview of major synthetic methodologies involved in the ring opening of oxetanes as well as their synthetic applications has been presented. 相似文献
80.
A simulation study has been performed to quantify the effect of volume reduction on the thyroid absorbed dose per decay and to investigate the variation of energy deposition per decay due to β- and γ-activity of ~(131)I with volume/mass of thyroid,for water,ICRP- and ICRU-soft tissue taken as thyroid material.A Monte Carlo model of the thyroid,in the Geant4 radiation transport simulation toolkit was constructed to compute the β- and γ-absorbed dose in the simulated thyroid phantom for various values of its volume.The effect of the size and shape of the thyroid on energy deposition per decay has also been studied by using spherical,ellipsoidal and cylindrical models for the thyroid and varying its volume in 1-25 cm~3 range.The relative differences of Geant4 results for different models with each other and MCNP results he well below 1.870%.The maximum relative difference among the Geant4estimated results for water with ICRP and ICRU soft tissues is not more than 0.225%.S-values for ellipsoidal,spherical and cylindrical thyroid models were estimated and the relative difference with published results lies within3.095%.The absorbed fraction values for beta particles show a good agreement with published values within 2.105%deviation.The Geant4 based simulation results of absorbed fractions for gammas again show a good agreement with the corresponding MCNP and EGS4 results(±6.667%) but have 29.032%higher values than that of MIRD calculated values.Consistent with previous studies,the reduction of the thyroid volume is found to have a substantial effect on the absorbed dose.Geant4 simulations confirm dose dependence on the volume/mass of thyroid in agreement with MCNP and EGS4 computed values but are substantially diiferent from MIRD8 data.Therefore,inclusion of size/mass dependence is indicated for ~(131)I radiotherapy of the thyroid. 相似文献