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991.
Das AK Chakraborty R Cervera ML de la Guardia M 《Analytical and bioanalytical chemistry》2006,385(4):665-670
Determination of thallium has become a major interest because of its high toxicity, especially as the monovalent cation. Thallium poisoning in the human body must be checked quickly by analysis of biological samples. This review highlights the development of highly sensitive detection techniques applied to the determination of thallium in biological samples, with or without pretreatment, based on the literature compiled in Analytical Abstracts from 1990. 相似文献
992.
Sambuddha Banerjee Susmita Mondal Writachit Chakraborty Soma Sen Ratan Gachhui Ray J. Butcher Alexandra M.Z. Slawin Chitra Mandal Samiran Mitra 《Polyhedron》2009,28(13):2785-2793
From a mononuclear Cu(II)-hydrazone complex [Cu(PBH)2] (1), one μ1,1-azido bridged dinuclear Cu(II) complex having the formula [{Cu(PBH)(μ1,1-NNN)}2] (2) (where HPBH = 2-pyridinecarboxaldehyde benzoyl hydrazone) has been synthesised. Both the complexes are characterised by elemental analyses, IR and UV–Vis spectroscopic studies. The tridentate hydrazone pro-ligand (HPBH) is obtained by the condensation of benzhydrazide and pyridine-2-carboxaldehyde. The structures of the complexes have conclusively been established by the X-ray single crystal diffraction method. Complex 1 and 2 both display DNA binding ability, which is ascertained by UV–Vis titration and cyclic voltammetric studies using calf thymus DNA (CT-DNA). The apparent binding constants (Kapp) are of moderate values and are 2.048 × 104 M−1 (±0.006) and 1.644 × 104 M−1 (±0.005), respectively. The modes of binding of the complexes with CT-DNA has been investigated using circular dichroism, ethidium bromide displacement assay and viscosity measurements. The cleavage properties of these complexes as well as the free pro-ligand with super coiled (SC) pUC19 are studied using the gel electrophoresis method, where both the complexes displayed chemical nuclease activity in the presence of H2O2 via an oxidative mechanism. The antimicrobial study using the free pro-ligand, 1 and 2 against both Gram positive and Gram negative bacteria are performed, 2 showed antimicrobial activity against both Gram negative and Gram positive bacteria whereas the free ligand and 1 show no antibacterial activity. 相似文献
993.
A novel tetranuclear complex, [Cu4L4] · Na · ClO4 (1) has been prepared from an interesting multidentate Schiff base ligand H2L resulting from the 1:1 condensation of 3-methoxysalicylaldehyde with benzhydrazide. The prepared complex has been characterized by elemental analysis, FT-IR, UV–Vis spectroscopy, electrochemical studies and single crystal X-ray diffraction analysis. The Cu4O4 cubane core consists of four μ3-phenoxo-bridged copper(II) atoms giving an approximately cubic array of alternating copper(II) and oxygen atoms. Magneto-structural correlations have been drawn from cryomagnetic susceptibility measurements over a wide range of temperature (2–300 K) under 0.5 T magnetic field. The measurements reveal both ferromagnetic and antiferromagnetic interactions in a 2J model [J11 = +13.6(4) cm−1 and J12 = −34.9(4) cm−1] which in turn results in an overall antiferromagnetic behaviour of the magnetic system. 相似文献
994.
J.P. Maity S. Kar S. Banerjee A. Chakraborty S.C. Santra 《Radiation Physics and Chemistry》2009,78(11):1006-1010
We have reported an effective 60Co gamma irradiation method for the removal and long-time prevention of contaminating fungi of Oryza sativa cv-2233, without the losses of seed viabilities. The fungal growth and their population on gamma treated seeds was found to decrease significantly (p<0.05) with the increasing irradiation dose and storage time. Immediately after irradiation, the depletion of fungal population on rice seed was noticed (>50%) at 2 kGy, whereas total inhibition was noticed at 3 kGy after 1.5 month. 相似文献
995.
996.
M. Muthu Rama Krishnan Pratik Shah Mousumi Pal Chandan Chakraborty Ranjan Rashmi Paul Jyotirmoy Chatterjee Ajoy K. Ray 《Micron (Oxford, England : 1993)》2010,41(4):312-320
This article presents a quantitative approach for the characterization of normal oral mucosa (NOM) in respect to thickness and textural properties of its entire epithelial layer. Histological images of oral mucosa depict that both thickness and tissue architecture at cellular and tissue level undergo change, as mucosa converts from normal to precancerous or cancerous state. In this study the thickness and fractal dimension of the mucosal epithelium of NOM and oral sub-mucous fibrosis (OSF) condition have been computed using 83 normal and 29 OSF images of oral mucosa. The result shows significant delineation between NOM and OSF in respect of both the epithelial thickness (in μm) and fractal dimensions. This quantitative characterization of oral epithelium will be of immense help for oral onco-pathologists and researchers to assess the biological nature of normal and diseased (OSF) mucosa with higher accuracy. Moreover, further differential applications may enable them to find out newer accurate quantitative diagnostic procedures to that of the usual histopathological gold standard for the assessment of malignant potentiality. 相似文献
997.
Nairwita Mazumder Subenoy Chakraborty 《The European Physical Journal C - Particles and Fields》2010,70(1-2):329-334
In this paper, we examine the validity of the generalized second law of thermodynamics of the universe bounded by the event horizon in brane-world gravity. Here we consider a homogeneous and isotropic model of the universe in the one case where it is filled with a perfect fluid and in another case where a holographic dark energy model of the universe has been considered. 相似文献
998.
Several matrix methods have been developed for studying polarization properties of light. Jones was the first to apply the matrix method to the study of polarization optics. In Jones matrix formalism the polarized wave field is represented by 2-element column matrix known as Jones Vector and the polarization device encountered by light is represented by a 2×2 matrix, known as the characteristic Jones matrix of the device. Mueller introduced a new matrix method where the wave field is represented by a 4-dimensional vector. The elements of the vector are the Stokes parameters of the beam. In Mueller matrix formalism the optical device is represented by a 4×4 real matrix known as ‘Mueller Matrix’ of the device. The use of coherency matrix also proves to the useful in the study of partially polarized light. Pauli spin matrices have been used to unify the different matrix treatments of polarization optical phenomena. The present article is an attempt to unify the analysis of polarization phenomena using Dirac matrices used by Dirac in quantum mechanics. We have however redefined the set of Dirac matrices in terms of the Kronecher product of Pauli spin matrices. 相似文献
999.
Shuvendu Chakraborty Ujjal Debnath 《International Journal of Theoretical Physics》2010,49(8):1693-1698
We have considered N-dimensional Einstein field equations in which four-dimensional space-time is described by a FRW metric and that of extra
dimensions by an Euclidean metric. We have supposed that the higher dimensional anisotropic universe is filled with only normal
scalar field or tachyonic field. Here we have found the nature of potential of normal scalar field or tachyonic field. From
graphical representations, we have seen that the potential is always decreases with field φ increases. 相似文献
1000.
Asit Banerjee Tanwi Bandyopadhyay Subenoy Chakraborty 《General Relativity and Gravitation》2008,40(8):1603-1607
A model of an emergent universe is obtained in brane world. Here the bulk energy is in the form of cosmological constant,
while the brane consists of a fluid satisfying an equation of state of the form , which is effectively a radiation equation of state at high energies. It is shown that with the positive bulk cosmological
constant, one of our models represents an emergent universe. 相似文献