Kinetics and mechanism of the oxidation of 2-furancarbox-aldehyde by thallium(III) in perchloric acid solutions

The kinetics of the oxidation of 2-furancarboxaldehyde by thallic perchlorate at 50°C obeys the rate law

Studies on Biologically Potent Tetraazamacrocyclic Complexes of Bivalent Tin

Fourteen- to eighteen-membered tetraamide macrocyclic ligands N 4 L 1 -N 4 L 4 have been prepared by the condensation of 1,2-diaminoethane or 1,3-diaminopropane with malonic or succinic acid in the presence of condensing reagents dicyclohexylcarbodiimide and 4-dimethylaminopyridine. On reduction, these macrocyclic ligands give a new series of tetraazamacrocycles MacL 1 -MacL 4 which form complexes with tin(II) chloride. The ligands and their complexes were characterized by elemental analyses, molecular weight determinations, infrared and 1 H NMR spectral studies. The hexacoordinated state for tin has been confirmed by spectral studies. An octahedral geometry for these complexes has been proposed as the binding sites are the nitrogen atoms of the macrocycles. On the basis of the chemical composition the representation of the complexes as [Sn(MacL n )Cl 2 ] (n = 1-4) has been established. The ligands and their complexes also have been screened for their antifungal and antibacterial activities and the findings have been reported and explained.     

Chemical modification of L-glutamine to alpha-amino glutarimide on autoclaving facilitates Agrobacterium infection of host and non-host plants: A new use of a known compound

Background

Accidental autoclaving of L-glutamine was found to facilitate the Agrobacterium infection of a non host plant like tea in an earlier study. In the present communication, we elucidate the structural changes in L-glutamine due to autoclaving and also confirm the role of heat transformed L-glutamine in Agrobacterium mediated genetic transformation of host/non host plants.

Results

When autoclaved at 121°C and 15 psi for 20 or 40 min, L-glutamine was structurally modified into 5-oxo proline and 3-amino glutarimide (α-amino glutarimide), respectively. Of the two autoclaved products, only α-amino glutarimide facilitated Agrobacterium infection of a number of resistant to susceptible plants. However, the compound did not have any vir gene inducing property.

Conclusions

We report a one pot autoclave process for the synthesis of 5-oxo proline and α-amino glutarimide from L-glutamine. Xenobiotic detoxifying property of α-amino glutarimide is also proposed.     

Molecular dynamics simulation of (100)InGaAs/GaAs strained-layer relaxation processes

Molecular dynamics simulations on In_1−xGa_xAs/GaAs(100) systems are performed showing the dynamics of threading dislocations in the overlayers and the formation of misfit dislocations at the heterojunction interface. The developed code, using a modified Tersoff potential, simulates the threading dislocation dynamics in the InGaAs overlayer, and also the formation of interface misfit dislocations. Values for critical thicknesses are predicted and the atomic structure of the dislocation cores are determined.     

Transient analysis of diffusive chemical reactive species for couple stress fluid flow over vertical cylinder

The unsteady natural convective couple stress fluid flow over a semi-infinite vertical cylinder is analyzed for the homogeneous first-order chemical reaction effect. The couple stress fluid flow model ...     

In-situ X-ray imaging of III-V strained-layer relaxation processes

The important value of the X-ray topography (XRT) technique for the investigation of III-V strained-layer relaxation processes is described. In addition to post-growth ex-situ XRT studies, a unique combined XRT/MBE growth facility has been constructed which allows the generation, motion and interaction of misfit dislocations to be monitored in-situ during epilayer growth, for the first time. The in-situ data already obtained for (100) InGaAs strained-layer growth on both Czochralski- and vertical-gradient freeze-grown GaAs substrates indicates technologically important differences in the initial relaxation process, including, in the latter case, the observation of a previously unreported secondary relaxation phase. Initial results relating to the influence of both post-growth annealing and the subsequent cool-down process are also described.     

l-Glutamine and l-Glutamic Acid Facilitate Successful Agrobacterium Infection of Recalcitrant Tea Cultivars

The first step in Agrobacterium tumefaciens infection of plants is the establishment of cell–cell contact between the two partners. However, failure to establish such contact makes many plants and explants recalcitrant to A. tumefaciens infection. Tea is one such example where even the popular inducer, acetosyringone failed to facilitate A. tumefaciens infection due to the presence of high amounts of bactericidal/bacteriostatic polyphenols. Quinones are formed as a result of polyphenols oxidation. They cause tissue browning and necrosis during the process of transformation, and in turn prevent A. tumefaciens infection. Compounds such as polyphenol adsorbents, i.e., polyvinylpyrrolidone and charcoal, and antioxidants like cysteine and ascorbic acid were screened to overcome tissue browning. Although these compounds enhanced the growth of A. tumefaciens, these failed to facilitate the infection of the leaves of either Kangra Jat, Tocklai Variety-1, UPASI-9, UPASI-10, and Stock-449 cultivars of tea. On the contrary, the presence of filter sterilized l-glutamine and l-glutamic acid in the co-cultivation medium facilitated successful A. tumefaciens infection of recalcitrant tea leaves. l-Glutamine and glutamic acid form harmless adducts by binding to quinones. Therefore, their presence in the co-cultivation medium allowed the tea leaves to remain living and appealing to the infecting A. tumefaciens. Successful A. tumefaciens infection of tea leaves was confirmed by positive signals in GUS assay, PCR, and Dot blot.     

Axioms of spheres in lightlike geometry of submanifolds

We prove that if an indefinite Kaehler manifold \(\bar {M}\) with lightlike submanifolds satisfies the axioms of holomorphic 2r-spheres, axioms of holomorphic 2r-planes, axioms of transversal r-spheres and axioms of transversal r-planes, then it is an indefinite complex space form.     

Pyrene functionalized oxacalix[4]arene architecture as dual readout sensor for expeditious recognition of cyanide anion

A pyrene functionalized oxacalix[4]arene architecture (DPOC) was utilized as a fluorescence probe for selective recognition of cyanide ions. The receptor DPOC shows excellent selectivity towards cyanide ion with a red shift of 108 nm in absorption band along with a significant change in colour from light yellow to pink. The fluorescence titration experiments further confirm the lower limit of detection as 1.7µM with no significant influences of competing anions. ¹ H-NMR titration experiments support the deprotonation phenomena, as the -NH proton disappears upon successive addition of cyanide ions. The DFT calculation also indicates a certain increment of -NH bond length upon interaction with cyanide ions. The spectral properties as well as colour of DPOC-CN^? system may be reversed upon the addition of Ag⁺/ Cu²⁺ ions up to 5 consecutive cycles. Moreover, DPOC coated “test strips” were prepared for visual detection of cyanide ions.