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2.
Priyabrata Das Suvra Mandal Sudeshna Gangopadhyay Kalipada Das Arpita Ghosh Mitra Swati Dasgupta 《Natural product research》2016,30(4):474-477
Methylphophorbide a (MPa) has been isolated from the ethanol extract of the wheat grass plant. Its antioxidative efficacy is evaluated by hydroxyl radical scavenging activities and reducing capacity which are significantly up regulated in comparison with aqueous extract of the plant. The compound shows iron-binding capacity where the Fe2+ binds with MPa by two types of binding patterns with dissociation constants 157.17 and 27.89. It has antioxidative and cytotoxic effects on HeLa and Hep G2 cells. The cancerous cell survivability decreases with increasing concentration of MPa. These findings have provided evidence for the traditional use of the wheat grass plant in the treatment of cancers, oxidative stress and iron overloaded disorders. 相似文献
3.
Excellent Performance of Few‐Layer Borocarbonitrides as Anode Materials in Lithium‐Ion Batteries
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Borocarbonitrides (BxCyNz) with a graphene‐like structure exhibit a remarkable high lithium cyclability and current rate capability. The electrochemical performance of the BxCyNz materials, synthesized by using a simple solid‐state synthesis route based on urea, was strongly dependent on the composition and surface area. Among the three compositions studied, the carbon‐rich compound B0.15C0.73N0.12 with the highest surface area showed an exceptional stability (over 100 cycles) and rate capability over widely varying current density values (0.05–1 A g?1). B0.15C0.73N0.12 has a very high specific capacity of 710 mA h g?1 at 0.05 A g?1. With the inclusion of a suitable additive in the electrolyte, the specific capacity improved drastically, recording an impressive value of nearly 900 mA h g?1 at 0.05 A g?1. It is believed that the solid–electrolyte interphase (SEI) layer at the interface of BxCyNz and electrolyte also plays a crucial role in the performance of the BxCyNz . 相似文献
4.
Sudeshna Basu 《Indagationes Mathematicae》2002,13(2):169-175
The Ball Generated Property (BGP) was introduced by Corson and Lindenstrauss and subsequently analysed in detail by Godefroy and Kalton. In this work, the (BGP) is studied in spaces of operators. It is shown that (BGP) is stable under c0 and lp-sums for 1 < p < ∞ and a characterization is provided for C(K, X)-spaces with (BGP). A similar characterization is obtained for L(X, C(K))-spaces. (BGP) is shown to be stable under injective tensor products. 相似文献
5.
Yogesh P. Bharitkar Siddharth Shah Sudeshna Saha Anil Kumar Matoori 《Natural product research》2015,29(19):1850-1856
Phytochemical investigation of the plant Clerodendrum phlomidis Linn. F. (Lamiaceae) has now led to the isolation of two new flavonoid glycosides (1, 2) together with six known compounds identified as pectolinaringenin (3), pectolinaringenin-7-O-β-d-glucopyranoside (4), 24β-ethylcholesta-5,22E,25-triene-3β-ol (5), 24β-ethylcholesta-5,22E,25-triene-3β-O-β-D-glucopyranoside (6), (2S,3S,4R,10E)-2-[(2′R)-2′-hydroxytetracosanoylamino]-10-octadecene-1,3,4-triol (7) and andrographolide (8) mainly by spectroscopic analysis. Compounds 4 and 6–8 are reported for the first time from C. phlomidis. 相似文献
6.
Construction of a thin magnetic lens β-ray spectrometer is described. A baffle system which takes advantage of the ring focus has been designed on the basis of the calculations of electron trajectories limited to an angle of acceptance of 9–10·5 degrees. The results of the study of the β-ray spectra of Sr90 and Y90, Pm147, Tm170 are presented. 相似文献
7.
Chaotic systems can yield a wide variety of patterns. Here we use this feature to generate all possible fundamental logic gate functions. This forms the basis of the design of a dynamical computing device, a chaogate, that can be rapidly morphed to become any desired logic gate. Here we review the basic concepts underlying this and present an extension of the formalism to include asymmetric logic functions. 相似文献
8.
It was observed that the spatiotemporal chaos in lattices of coupled chaotic maps was suppressed to a spatiotemporal fixed
point when some fractions of the regular coupling connections were replaced by random links. Here we investigate the effects
of different kinds of parametric fluctuations on the robustness of this spatiotemporal fixed point regime. In particular we
study the spatiotemporal dynamics of the network with noisy interaction parameters, namely fluctuating fraction of random
links and fluctuating coupling strengths. We consider three types of fluctuations: (i) noisy in time, but homogeneous in space;
(ii) noisy in space, but fixed in time; (iii) noisy in both space and time. We find that the effect of different kinds of
parametric noise on the dynamics is quite distinct: quenched spatial fluctuations are the most detrimental to spatiotemporal
regularity; spatiotemporal fluctuations yield phenomena similar to that observed when parameters are held constant at the
mean value, and interestingly, spatiotemporal regularity is most robust under spatially uniform temporal fluctuations, which
in fact yields a larger fixed point range than that obtained under constant mean-value parameters. 相似文献
9.
With the help of electrochemical, steady state and time resolved fluorescence (fluorescence lifetimes by using time correlated single photon counting technique) and nanosecond laser flash photolysis methods, the nature of charge separation along with the energy wasting charge recombination processes within a short-chained organic dyad 1-(4-Bromo-phenyl)-3-(2-methoxy-naphthalen-1-yl)-propenone (MNBA) has been revealed. In MNBA, the donor 2-methoxynaphthalene (2MNT) is connected with the acceptor p-bromoacetophenone (PBA) by an unsaturated olefinic bond. Though in the ground state elongated type structure (E-form) is observable from NMR spectra but on photoexcitation, another conformers possibly of the nature of folded type isomeric species (termed as Z-isomer) were also apparent from time resolved fluorescence measurements. However, preponderance of elongated form in the excited singlet state has been established from this time resolved measurements. NMR study on photoirradiated sample and theoretical predictions from computations using CIS method with Lanl2DZ basis set also indicate in favor of the propositions made on the formations of the two possible conformers and the stability of elongated isomeric species in the electronic excited state from the experimental results. The energy wasting charge recombination rate, kCR, determined from the transient absorption measurements by nanosecond laser flash photolysis (LFP) technique was found to be (kCR, ∼1.9×105 s−1) significantly lower than the charge-separation rate, kcs∼9.4×107 s−1, measured from the time resolved fluorescence. This observation demonstrates that MNBA may serve as an efficient candidate to construct artificial light energy conversion devices or components of molecular photovoltaic cells. 相似文献
10.
Sudeshna Mukerji Subenoy Chakraborty 《International Journal of Theoretical Physics》2010,49(10):2446-2455
In this work, Emergent Universe scenario has been developed in Einstein-Gauss-Bonnet (EGB) theory. The universe is chosen
as homogeneous and isotropic FRW model and the matter in the universe has two components—the first one is a perfect fluid
with barotropic equation of state p=ω
ρ (ω, a constant) and the other component is a real or phantom (or tachyonic) scalar field. Various possibilities for the existence
of emergent scenario has been discussed and the results are compared with those in Einstein gravity. 相似文献