Synthesis, structural elucidation and X-ray analysis of triphenyltin(IV) [2-(2,3-dimethylanilino)nicotinate]

Triphenyltin(IV) [2-(2,3-dimethylanilino)nicotinate] was prepared by the interaction of triphenyltin(IV) hydroxide and 2-(2,3-dimethylanilino)nicotinic acid in 1:1 ratio. This compound was characterized by elemental analyses, IR, multinuclear NMR spectroscopy (¹H and ¹³C) and mass spectrometry. The structure of title compound was confirmed by single crystal X-ray crystallography. The coordination around the tin atom was studied both in solution and solid state. The geometry around tin is trigonal bipyramidal in solid state while it is tetrahedral in solution. The compound belongs to Monoclinic system, having space group P 21/c with unit cell dimensions a = 17.002(8) Å, b = 9.0793(3) Å, c = 18.2616(9) Å, α = 90 (°) β = 107.381(4) (°), γ = 90 (°).     

The role of Rho GTPases in the regulation of the rearrangement of actin cytoskeleton and cell movement

The rearrangement of the actin cytoskeleton has been shown to play a critical role in the development of transformation and malignant phenotype of cancer cells. Rho family GTPases regulate the arrangement of the actin cytoskeleton. By wound-healing assay, we have found that NIH 3T3 fibroblast cells move towards the wound- gaps by extending filopodial and lamellipdial structures at the leading edge of the moving cells. We have inactivated the function of Rho GTPases of v-Ras transformed NIH 3T3 cells by overexpressing Rho GTPase-activating (RhoGAP) domain of RhoGAP of p190. We have observed that inactivation of Rho, Rac and Cdc42 GTPases by overexpressing RHG causes inhibition of: (i) polymerization of actin to form filaments, (ii) formation of lamellipodia, filopodia and stress fibres, (iii) cell motility, (iv) cell spreading and (v) cell-to-cell adhesions. These results further strengthen the current knowledge on the role of Rho, Rac and Cdc42 GTPases in the regulation of the rearrangement of actin cytoskeleton. Our results, for the first time, demonstrate that RhoGAP domain of RhoGAP could be used to study the molecular mechanism of Ras-mediated signalling in growth, differentiation and carcinogenesis.     

Fluorescence assays for high-throughput screening of protein kinases

Protein kinases comprise one of the most important group of targets for drug discovery research today. Methods to identify novel kinase inhibitors by high-throughput screening have evolved rapidly in recent years. An important aspect is the availability of fluorescent probes that can be applied in a homogeneous, or mix-and-measure, assay format. Here, we illustrate the application of fluorescence read-out technologies for kinase targets in light of our own experiences in assay development and high-throughput screening.     

Crystal engineering using anilic acids and dipyridyl compounds through a new supramolecular synthon

The anilic acids, 2,5-dihydroxy-1,4-benzoquinone (1a), 2,5-dibromo-3,6-dihydroxy-1,4-benzoquinone (bromanilic acid; 1b), 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid; 1c), and 2,5-dicyano-3,6-dihydroxy-1,4-benzoquinone (cyananilic acid; 1d), were cocrystallized with rigid organic ligands containing two pyridine rings, 2,4-bipyridine (2a), 4,4'-bipyridine (2b), 1,2-bis(2-pyridyl)ethylene (3a), 1,2-bis(4-pyridyl)ethylene (3b), 2,2'-dipyridylacetylene (4a), 3,3'-dipyridylacetylene (4b), and 4,4'-dipyridylacetylene (4c). Fourteen complexes 5-18 were obtained as single crystals, and their crystal structures were successfully determined by X-ray analysis. All complexes except those with 2a are 1:1 and are composed of an infinite linear or zigzag tape structure, the formation of which is ascribed to intermolecular O-H...N, N(+)-H...O, or N(+)-H...O(-) hydrogen bonds or a combination of these between the anilic acids and the dipyridyl compounds. In the complexes 5 and 6, no infinite tape structure is observed although the molecular units connected by a similar hydrogen-bonding pattern are formed. For the 1:1 complexes, we have found two types of stacking arrangements, segregated stacks (7, 9, 12-15, 18) and alternated ones (8, 10, 11, 16, 17). In the complexes of 1c with the series of dipyridylacetylenes 4 (14, 15, 17), the neutral, dication, and monocaction states are formed depending on the nitrogen positions, which can be attributed to the different basicity of the pyridyl groups.     

Optimal government scrappage subsidies in the presence of strategic consumers

Many countries have introduced vehicle scrappage programs to motivate consumers to replace their old cars earlier. Since these programs are generally offered over a given period of time, policy makers need to plan for inter-temporal subsidies. Considering a two-period game between strategic consumers and the government, we determine the optimal scrappage subsidy levels. Our results demonstrate that the subsidy level in the second period is higher than in the first, allowing the government to discriminate on price (or subsidy) between consumers with different valuations. In addition, we show that subsidy levels increase with the government’s targeted replacement level. However, when the government target level changes from intermediate to high, the first-period subsidy drops while the second-period subsidy remains unchanged.     

Nucleus-acoustic solitary waves in self-gravitating degenerate quantum plasmas

Nucleus-acoustic(NA) solitary waves(SWs) propagating in a self-gravitating degenerate quantum plasma(SDQP)system(containing non-relativistically degenerate heavy and light nuclei,and non-/ultra-relativistically degenerate electrons) have been theoretically investigated.The modified Korteweg–de Vries(m K-d V) equation has been derived for both planar and non-planar geometry by employing the reductive perturbation technique.It is shown that the NA SWs exist with positive(negative) electrostatic(self-gravitational) potential.It is also observed that the effects of non-/ultra-relativistically degenerate electron pressure,dynamics of non-relativistically light nuclei,spherical geometry,etc.significantly modify the basic features(e.g.,amplitude,width,speed,etc.) of the NA SWs.The applications of our results,which are relevant to astrophysical compact objects,like white dwarfs and neutron stars,are briefly discussed.     

Comparative analysis of oil composition and antibacterial activity of aerial parts of Terminalia arjuna (Roxb.)

Abstract

Volatile oil composition of leaves and fruits of Terminalia arjuna (Roxb.) was reported for the first time. Oils were extracted by microwave assisted hydrodistillation where yield of both oils were found to be 0.20% and their GC-MS analyses led to the identification of 65 and 48 constituents, respectively. Major constituents of leaves were carvacrol (11.17%), thymol (6.52%), α-terpinyl acetate (5.92%) and anethole (5.13%) while that of fruits were (E)-isoeugenol (11.48%), furfural (8.25%), p-vinylguaiacol (6.8%) and p-ethylguaiacol (5.72%) that demonstrated a significant difference between composition of its aerial parts, however, 33 constituents were identical that showed similarity characteristics in quality of these oils. Both leaf and fruit oils were found active against pathogenic and drug-resistant microbes: E. coli, Methicillin-resistant S. aureus, P. aeruginosa, Total-drug-resistant P. aeruginosa and K. pneumoniae with MIC values of 0.32, 0.32, 0.64, 0.64, 2.56?mg/mL and 0.16, 0.16, 0.32, 0.64, 1.28?mg/mL, respectively.     

Synthesis of trisubstituted imidazoles by palladium-catalyzed cyclization of O-pentafluorobenzoylamidoximes: application to amino acid mimetics with a C-terminal imidazole

1-Benzyl-4-methylimidazoles with a range of substituents at the 2-position are prepared from O-pentafluorobenzoylamidoximes on treatment with catalytic amounts of Pd(PPh3)4 and triethylamine. The sequence provides access to optically active amino acid mimetics with a C-terminal imidazole. [structure: see text]     

New measurements concerning a non-resonant photo-activation cross-section for Cd

A ⁶⁰Co source of high activity has been used to photo-activate the 396 keV isomeric level (T_1/248.6 min) of ¹¹¹Cd. Present results support the existence of a non-resonant contribution to the photo-activation cross-section, the magnitude of our current estimate comparing favourably with measurements obtained by a number of other workers.