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81.
Jagbir Singh Harjeet Kaur Arvind Sharma J. Goswamy D. Mehta Nirmal Singh R. K. Bhowmik P. N. Trehan 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(2):125-126
Two new neutron-deficient isotopes,213Pa and214Pa were produced in complete fusion reactions of51V-ions with170Er targets at (5.2–5.6) AMeV. The assignment was based on delayed evaporation residue - - time and position coincidences. The- decay energies of213,214Pa were measured to be E=(8236±20) keV and E=(8116±20) keV, respectively. The half-lives of213,214Pa were determined to be T1/2=(5.3
–1.6
+4.0
ms and T1/2=(17 ±3) ms, respectively.This article was processed by the author using the LATEX style filecljour2 from Springer-Verlag. 相似文献
82.
Dr. Juliane Adler Monika Baumann Bruno Voigt Dr. Holger A. Scheidt Dr. Debanjan Bhowmik Dr. Tilmann Häupl Prof. Dr. Bernd Abel Prof. Dr. Perunthiruthy K. Madhu Prof. Dr. Jochen Balbach Prof. Dr. Sudipta Maiti Prof. Dr. Daniel Huster 《Chemphyschem》2016,17(17):2744-2753
A small library of rationally designed amyloid β [Aβ(1–40)] peptide variants is generated, and the morphology of their fibrils is studied. In these molecules, the structurally important hydrophobic contact between phenylalanine 19 (F19) and leucine 34 (L34) is systematically mutated to introduce defined physical forces to act as specific internal constraints on amyloid formation. This Aβ(1–40) peptide library is used to study the fibril morphology of these variants by employing a comprehensive set of biophysical techniques including solution and solid‐state NMR spectroscopy, AFM, fluorescence correlation spectroscopy, and XRD. Overall, the findings demonstrate that the introduction of significant local physical perturbations of a crucial early folding contact of Aβ(1–40) only results in minor alterations of the fibrillar morphology. The thermodynamically stable structure of mature Aβ fibrils proves to be relatively robust against the introduction of significantly altered molecular interaction patterns due to point mutations. This underlines that amyloid fibril formation is a highly generic process in protein misfolding that results in the formation of the thermodynamically most stable cross‐β structure. 相似文献
83.
Vivek?Kumar P.?Thakur A.?K.?BhatiEmail author R.?P.?Singh R.?K.?Bhowmik 《The European Physical Journal A - Hadrons and Nuclei》2005,26(3):311-314
The nuclear spectroscopic quadrupole moments for the πh9/25/2-, 1/2-[541] and the πh11/29/2-, 9/2-[514] isomeric states in 169Ta have been measured employing the time differential perturbed angular-distribution technique following the nuclear reaction
159Tb(16O, 6nγ)169Ta at beam energy 104 MeV. The ratio of the intrinsic quadrupole moments
has been derived as 1.87(13) from the measured quadrupole precession frequencies of the corresponding states. The model-independent
analysis of the equilibrium deformation indicates strong prolate- and oblate-driving nature of the 1/2-[541] and 9/2-[514] orbitals in 169,171Ta isotopes, respectively. 相似文献
84.
R.K. Bhowmik E.C. Pollacco J.B.A. England G.C. Morrison N.E. Sanderson 《Nuclear Physics A》1981,363(2):516-532
Energy and angular correlations between α-particles and heavy ejectiles have been measured for 148 MeV 14N incident on 12C, 27Al and 58Ni targets. The coincidence cross sections for ejectiles with Z < 6 may be parametrised as a product of singles cross sections for the detection of α-particles and heavy ions. For 27Al and 58Ni targets, this indicates that the α-particles are emitted at an early stage of the reaction prior to the formation of the deep inelastic fragments. For the 12C target, however, kinematic effects are found to dominate the observed correlations. For ejectiles the observed correlations appear consistent with the emission of α-particles from the recoiling nucleus produed in the reaction. 相似文献
85.
86.
Li S Fuller JF Wang X Sohnlein BR Bhowmik P Yang DS 《The Journal of chemical physics》2004,121(16):7692-7700
The ethylenediamine (en) complexes of Al, Ga, and In atoms were prepared in laser-vaporization supersonic molecular beams and studied with pulsed field ionization zero electron kinetic energy photoelectron spectroscopy and density functional theory. Several conformers of each metal complex are obtained by B3LYP calculations, and a five-membered cyclic structure is identified by combining the experimental measurements and theoretical calculations. Adiabatic ionization potentials, vibrational frequencies, and bond dissociation energies are determined for the ring structure. The ionization potentials of the Al, Ga, and In species are measured to be 32 784 (5), 33 324 (5), and 33 637 (7) cm(-1), respectively, and metal-ligand dissociation energies of the ionic and neutral complexes are calculated to be 60.2/16.2 (Al(+)/Al), 55.5/13.0 (Ga(+)/Ga), and 50.0/11.4 (In(+)/In) kcal mol(-1). Metal-ligand stretch and bend as well as a number of ligand-based vibrations are measured. Harmonic frequencies and anharmonicities of the M(+)-N (M=Al,Ga,In) stretch are determined for all three M(+)-en ions and the C-C-N bend of Ga(+)-en and In(+)-en. In comparison to monodentate methylamine, the bidentate binding of ethylenediamine leads to a significantly lower ionization potential and higher metal-ligand bond strength of the metal complexes. 相似文献
87.
B Zhao H Hu S Niyogi M E Itkis M A Hamon P Bhowmik M S Meier R C Haddon 《Journal of the American Chemical Society》2001,123(47):11673-11677
We report an improved chromatographic purification of soluble single-walled carbon nanotubes (s-SWNTs) using gel permeation chromatography. Three fractions are separated by gel permeation chromatography, and the first fraction contains 74% of the s-SWNTs as detected by atomic force microscopy and UV and near-infrared spectroscopy. 相似文献
88.
Thakur P. Kumar V. Bhati A. K. Bedi S. C. Singh R. P. Muralithar S. Bhowmik R. K. 《Hyperfine Interactions》2001,136(3-8):201-204
The nuclear g-factor of 9/2− isomeric state in 171Ta at 184 keV has been measured as g(9/2−)=+0.515(3) using the TDPAD method following pulsed heavy-ion reaction and recoil implantation. Pulsed 16O ion beam (84 MeV) from the 15UD pelletron accelerator facility of Nuclear Science Centre at New Delhi was used in the reaction
159Tb(16O, 4nγ)171Ta.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
89.
90.
The first total synthesis of Bauerine C, a unique indoloquinazoline alkoloid, has been achieved from readily available 2,3‐dichloroaniline. The key step is the Japp–Klingmann condensation between 2,3‐dichloroaniline and ethyl‐2‐acetyl‐5‐phthalimido pentanoate to get 3‐[(2,3‐dichlorophenyl)‐hydrozono]‐pipiridin‐2‐one, which cyclizes to 7,8‐dichloro‐2,3,4,9‐tetrahydro‐β‐carbolin‐1‐one, which can be methylated by dimethyl sulphate to give 7,8‐dichloro‐9‐methyl 2,3,4,9‐tetrahydro‐β‐carbolin‐1‐one. This N‐methyl derivative is then subjected to dehydrogenation with 2,3‐dichloro‐5,6‐dicayano‐1,4‐benzoquinone (DDQ) to give the target compound Bauerine C. 相似文献