The Effect of Annealing Temperature on the Plasma Edge in Reflectance Spectra of Al/Al2O3 Composites Synthesized by Thermal Oxidation of Aluminum Thin Films

In this study, the structural and optical properties of aluminum oxide thin films were investigated. Aluminum oxide thin films were prepared on silicon and glass substrate by DC magnetron sputtering of aluminum targets with subsequent thermal oxidation of the aluminum-deposited thin films. Important result obtained included the presence of a plasma edge for the individual aluminum atoms. In addition, the temperatures that resulted in the highest concentration of surface plasmons were determined. On other hand, the relationship between the plasma edge and the optical energy gap was investigated.

     

AUX/LAX Genes Encode a Family of Auxin Influx Transporters That Perform Distinct Functions during Arabidopsis Development

Auxin transport, which is mediated by specialized influx and efflux carriers, plays a major role in many aspects of plant growth and development. AUXIN1 (AUX1) has been demonstrated to encode a high-affinity auxin influx carrier. In Arabidopsis thaliana, AUX1 belongs to a small multigene family comprising four highly conserved genes (i.e., AUX1 and LIKE AUX1 [LAX] genes LAX1, LAX2, and LAX3). We report that all four members of this AUX/LAX family display auxin uptake functions. Despite the conservation of their biochemical function, AUX1, LAX1, and LAX3 have been described to regulate distinct auxin-dependent developmental processes. Here, we report that LAX2 regulates vascular patterning in cotyledons. We also describe how regulatory and coding sequences of AUX/LAX genes have undergone subfunctionalization based on their distinct patterns of spatial expression and the inability of LAX sequences to rescue aux1 mutant phenotypes, respectively. Despite their high sequence similarity at the protein level, transgenic studies reveal that LAX proteins are not correctly targeted in the AUX1 expression domain. Domain swapping studies suggest that the N-terminal half of AUX1 is essential for correct LAX localization. We conclude that Arabidopsis AUX/LAX genes encode a family of auxin influx transporters that perform distinct developmental functions and have evolved distinct regulatory mechanisms.     

Synthesis of novel hetero ring fused pyridine derivatives; Their anticancer activity,CoMFA and CoMSIA studies

A series of novel furo[2,3-b]pyridine-2-carboxamide 4a–h/pyrido[3′,2′:4,5]furo[3,2-d] pyrimidin-4(3H)-one derivatives 5a–p were prepared from pyridin 2(1H) one 1 via selective O-alkylation with α-bromoethylester followed by cyclization, then reaction with different aliphatic primary amines to obtain 4 and further reaction with triethyl orthoacetate/triethyl orthoformate. Also prepared novel furo[2,3-b]pyridine-2-carbohydrazide Schiff’s bases 7a–h and pyrido [3′,2′:4,5]furo[3,2-d]pyrimidin-4(3H)-one derivatives 8a–h starting from furo[2,3-b]pyridine carboxylate derivatives 3 by reaction with hydrazine hydrate to form 6 and reaction with diverse substituted aldehydes and cyclization. Products 4a–h, 5a–p, 7a–h and 8a–h were screened against four human cancer cell lines (HeLa, COLO205, Hep G2 and MCF 7) and one normal cell line (HEK 293). Compounds 4e, 4f, 4g, 5h, 7c, 7d, 7e and 7f showed significant anticancer activity against all the cell lines at micro molar concentration and found to be non-toxic to normal cell line. Studies for HeLa, COLO205 and MCF-7 using CoMFA and CoMSIA. Models from 3D-QSAR provided a strong basis for future rational design of more active and selective HeLa, COLO205 and MCF-7 cell line inhibitors.     

Design, synthesis, and biological evaluation of substituted hydrazone and pyrazole derivatives as selective COX-2 inhibitors: Molecular docking study

New arylhydrazone derivatives and a series of 1,5-diphenyl pyrazoles were designed and synthesized from 1-(4-chlorophenyl)-4,4,4-trifuorobutane-1,3-dione 1. The newly synthesized compounds were investigated in vivo for their anti-inflammatory activities using carrageenan-induced rat paw oedema model. Moreover, they were tested for their inhibitory activity against ovine COX-1 and COX-2 using an in vitro cyclooxygenase (COX) inhibition assay. Some of the new compounds (2f, 6a and 6d) showed a reasonable in vitro COX-2 inhibitory activity, with IC?? value of 0.45 μM and selectivity index of 111.1. A virtual screening was carried out through docking the designed compounds into the COX-2 binding site to predict if these compounds have analogous binding mode to the COX-2 inhibitors. Docking study of the synthesized compounds 2f, 6a and 6d into the active site of COX-2 revealed a similar binding mode to SC-558, a selective COX-2 inhibitor.     

Biomechanics of a muscular hydrostat: a model of lapping by a reptilian tongue

We have developed a quantitative model of an example of a muscular hydrostat, a reptilian tongue, and have used this model to study a functional movement, protrusion and retrusion, a form of lapping. The model tongue consists of a longitudinal muscle that shortens the tongue when it contracts, and a circumferential muscle wrapped around the longitudinal muscle that lengthens the tongue when it contracts. The anatomy of the model tongue and the pattern of activation of its muscles are based on studies of the tongue of the lizard Tupinambis nigropunctatus (Smith 1984). The mechanics of pressure vessels were used to derive a relationship between the forces in the two muscles. Muscle force production was modelled as the product of length/tension properties, force/velocity properties, and activation due to neural inputs (incorporating both recruitment and firing period). Passive forces were modeled as a force in parallel with the longitudinal muscle. Muscle activation dynamics were modeled as a first order low pass filter. When the model tongue is short, the two muscles can lengthen or shorten it with comparable forces, but as it lengthens, the force that the circumferential muscle can exert drops precipitously. When the tongue is long, it can neither be very stiff, nor can it generate much force. The model also reproduces the kinematics of lapping movements actually observed in Tupinambis.     

Thermostable Enzymes in Organic Synthesis, 4. Tbadh-Catalyzed Preparation of Bifunctional Chirons. Total Synthesis of S-(+)-Z-Tetradec-5-En-13-Olide

Highly enantioselective reduction of various methyl- and ethylketones bearing different functional groups, such as double and triple carbon-carbon bonds, methyl ester, cyano, ethyl ether, phenyl and chloride, employing Thermoanaerobium brockii alcohol dehydrogenase (TBADH) as a catalyst, affords the corresponding optically active, secondary alcohols. As expected on the basis of our previous studies with monofunctional ketones, reduction of most of the substrates yields, uniformly, alcohols with an S configuration, arising from highly selective hydride attack at the re face of the carbonyl. However, with the smaller-sized ketones, there is a clear reversal in stereoselectivity. The synthetic usefulness of these chiral building blocks has been demonstrated by the total synthesis of (S)-(+)-Z-tetradec-5-en-13-olide, one of several synergistic aggregation pheromones produced by male flat grain beetles, Cryptolestes pusillus (Schonherr). The pheromone was prepared from (S)-(+)-methyl-8-hydroxynonanoate with optical purity greater than 99% in a six-step synthesis.     

Principles of cargo attachment to cytoplasmic motor proteins.

The attachment of cytoskeletal motor proteins to cargo-laden vesicles is crucial for efficient transport in intracellular membrane trafficking pathways. Recent studies have identified specific kinesin-binding and dynein-binding proteins that could serve as membrane-associated 'receptor' proteins for the respective motors. New insights have also emerged about the cargo-binding domains of the motor proteins, and the regulation of motor binding to cargoes.     

Enzymatic regeneration of aldehydes and ketones from hydrazones/oximes by baker's yeast in organic media

Summary Bio-oxidative regeneration of carbonyl compounds from phenylhydrazones, tosylhydrazones and oximes by non-immobilized baker's yeast in organic solvents has been demonstrated.IICT Communication No. 3068