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71.
In this paper we prove the existence of mild solutions for impulsive neutral evolution integrodifferential equations with infinite delay in Banach spaces. The results are obtained by using the analytic semigroup theory and the Krasnoselski–Schaefer type fixed point theorem. An example is provided to illustrate the theory. 相似文献
72.
Data available in the literature can be analyzed to determine the association energies of point defect complexes in acceptor-doped oxides. Data for very small amounts of acceptor-dopants in n-type, oxygen deficient oxides have been analyzed and defect association energies of the acceptor impurity and its compensating oxygen vacancy have been determined. Defect binding energies of approximately 1 eV are typical. 相似文献
73.
[structure: see text] C-Nucleosidation with cyclic iminium salts occurring under mild reaction conditions and affording C-nucleosides that are isosteric with N-nucleosides of natural purines is shown to be a consistent property of the entire family of 2,6-(oxo or amino)-disubstituted 5,8-diaza-7,9-dicarba-purines. 相似文献
74.
Wilds CJ Wawrzak Z Krishnamurthy R Eschenmoser A Egli M 《Journal of the American Chemical Society》2002,124(46):13716-13721
(L)-alpha-Threofuranosyl-(3'-->2')-oligonucleotides (TNA) containing vicinally connected phosphodiester linkages undergo informational base pairing in an antiparallel strand orientation and are capable of cross-pairing with RNA and DNA. TNA is derived from a sugar containing only four carbon atoms and is one of the simplest potentially natural nucleic acid alternatives investigated thus far in the context of a chemical etiology of nucleic acid structure. Compared to DNA and RNA that contain six covalent bonds per repeating nucleotide unit, TNA contains only five. We have determined the atomic-resolution crystal structure of the B-form DNA duplex [d(CGCGAA)Td(TCGCG)](2) containing a single (L)-alpha-threofuranosyl thymine (T) per strand. In the modified duplex base stacking interactions are practically unchanged relative to the reference DNA structure. The orientations of the backbone at the TNA incorporation sites are slightly altered in order to accommodate fewer atoms and covalent bonds. The conformation of the threose is C4'-exo with the 2'- and 3'-substituents assuming quasi-diaxial orientation. 相似文献
75.
S. Baez A. P. Balachandran S. Vaidya B. Ydri 《Communications in Mathematical Physics》2000,208(3):787-798
Monopoles and solitons have important topological aspects like quantized fluxes, winding numbers and curved target spaces.
Naive discretizations which substitute a lattice of points for the underlying manifolds are incapable of retaining these features
in a precise way. We study these problems of discrete physics and matrix models and discuss mathematically coherent discretizations
of monopoles and solitons using fuzzy physics and noncommutative geometry. A fuzzy σ-model action for the two-sphere fulfilling
a fuzzy Belavin–Polyakov bound is also put forth.
Received: 13 April 1999 / Accepted: 7 August 1999 相似文献
76.
In this paper, we present recent efforts conducted to investigate the dynamic behavior of a sensor diaphragm under initial
tension. A comprehensive mechanics model based on a plate with in-plane tension is presented and analyzed to examine the transition
from plate behavior to membrane behavior. It is shown that for certain tension parameter values, it is appropriate to model
the diaphragm as a plate-membrane structure rather than as a membrane. The model predictions are found to compare well with
experimental results. The analysis and results should be valuable for carrying out the design of circular sensor diaphragms
for various applications. 相似文献
77.
78.
V. Duraipandiyan N. A. AL-Dhabi C. Balachandran M. Karunai Raj M. Valan Arasu S. Ignacimuthu 《Applied biochemistry and biotechnology》2014,174(5):1784-1794
Streptomyces sp. isolate ERI-26 was obtained from the Nilgiris forest soil of Western Ghats, Tamil Nadu, India. Novel anthraquinone compound was isolated from the active fraction 5; it was identified by spectroscopical data using UV, IR, NMR and MASS. The isolated compound 1,5,7-trihydroxy-3-hydroxy methyl anthraquinone was tested against bacteria and fungi at minimum inhibitory concentration level. The compound showed significant antimicrobial activity against bacteria, Staphylococcus aureus at 125 μg/ml, Staphylococcus epidermidis at 62.5 μg/m, Bacillus subtilis at 31.25 μg/ml, fungi; Epidermophyton floccosum at 62.5 μg/ml, Aspergillus niger at 31.25 μg/ml, Aspergiller flavus at 31.25 μg/ml, Trichophyton rubrum at 62.5 μg/ml and Botrytis cinerea at 62.5 μg/ml. The isolated compound was subjected to molecular docking studies for the inhibition of TtgR, topoisomerase IV and AmpC β-lactamase enzymes which are targets for antimicrobials. Docking studies of the compound showed low docking energy indicating its usefulness as antimicrobial agent. 1,5,7-Trihydroxy-3-hydroxy methyl anthraquinone is new, and its antimicrobial and molecular docking properties are reported for the first time. Graphical Abstract
? 相似文献
79.
C. Balachandran Y. Arun V. Duraipandiyan S. Ignacimuthu K. Balakrishna N.A. Al-Dhabi 《Applied biochemistry and biotechnology》2014,172(7):3513-3528
Streptomyces galbus ERINLG-127 was isolated from the soil samples of the Marapalam forest, Nilgiris, India. The ethyl acetate extract was subjected to activity-guided fractionation by column chromatography over silica gel. This led to the isolation of 2,3-dihydroxy-9,10-anthraquinone as the active principle. The compound showed good antimicrobial activity against tested bacteria and fungi. The minimum inhibitory concentration values of isolated compound were 12.5 μg/mL against Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhimurium, K. pneumoniae (ESBL-3971), K. pneumoniae (ESBL-3894) and Staphylococcus aureus (MRSA). The compound showed prominent cytotoxic activity in vitro against A549 lung adenocarcinoma cancer cell line. It showed 75.1 % activity at the dose of 100 μg/mL with IC50 value of 60 μg/mL. The isolated compound was subjected to molecular docking studies for the inhibition of TtgR and Topoisomerase IV enzymes which are targets for antimicrobials. Docking studies of the compound showed low docking energy indicating its usefulness as antimicrobial agent. 相似文献
80.
A. P. Balachandran A. Ibort G. Marmo M. Martone 《General Relativity and Gravitation》2011,43(12):3531-3567
Physical considerations strongly indicate that spacetime at Planck scales is noncommutative. A popular model for such a spacetime
is the Moyal plane. The Poincaré group algebra acts on it with a Drinfel’d-twisted coproduct, however the latter is not appropriate
for more complicated spacetimes such as those containing Friedman-Sorkin (topological) geons. They have rich diffeomorphisms
and mapping class groups, so that the statistics groups for N identical geons is strikingly different from the permutation group S
N
. We generalise the Drinfel’d twist to (essentially all) generic groups including finite and discrete ones, and use it to
deform the commutative spacetime algebras of geons to noncommutative algebras. The latter support twisted actions of diffeomorphisms
of geon spacetimes and their associated twisted statistics. The notion of covariant quantum fields for geons is formulated
and their twisted versions are constructed from their untwisted counterparts. Non-associative spacetime algebras arise naturally in our analysis. Physical consequences, such as the violation of Pauli’s principle, seem
to be one of the outcomes of such nonassociativity. The richness of the statistics groups of identical geons comes from the
nontrivial fundamental groups of their spatial slices. As discussed long ago, extended objects like rings and D-branes also have similar rich fundamental groups. This work is recalled and its relevance to the present quantum geon context
is pointed out. 相似文献