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Chromosome 13 is the largest acrocentric human chromosome. It carries genes involved in cancer including the breast cancer type 2 (BRCA2) and retinoblastoma (RB1) genes, is frequently rearranged in B-cell chronic lymphocytic leukaemia, and contains the DAOA locus associated with bipolar disorder and schizophrenia. We describe completion and analysis of 95.5 megabases (Mb) of sequence from chromosome 13, which contains 633 genes and 296 pseudogenes. We estimate that more than 95.4% of the protein-coding genes of this chromosome have been identified, on the basis of comparison with other vertebrate genome sequences. Additionally, 105 putative non-coding RNA genes were found. Chromosome 13 has one of the lowest gene densities (6.5 genes per Mb) among human chromosomes, and contains a central region of 38 Mb where the gene density drops to only 3.1 genes per Mb.

This paper presents an analytical study on optimization of a laminated composite wing structure for achieving a maximum flutter speed and a minimum weight without strength penalty. The investigation is carried out within the range of incompressible airflow and subsonic speed. In the first stage of the optimization, attention has been paid mainly to the effect on flutter speed of the bending, torsion and, more importantly, the bending-torsional coupling rigidity, which is usually associated with asymmetric laminate lay-up. The study has shown that the torsional rigidity plays a dominant role, while the coupling rigidity has also quite a significant effect on the flutter speed. In the second stage of the optimization, attention has been paid to the weight and laminate strength of the wing structure, which is affected by the variation in laminate lay-up in the first stage. Results from a thin-walled wing box made of laminated composite material show that up to 18 per cent increase in flutter speed and 13 per cent reduction in weight can be achieved without compromising the strength. The investigation has shown that a careful choice of initial lay-up and design variables leads to a desirable bending, torsional and coupling rigidities, with the provision of an efficient approach when achieving a maximum flutter speed with a minimum mass of a composite wing.

Aqueous sol derived ferroelectric PbTiO3 thin films have been deposited on Si(100) substrates. Films crystallized by annealing at 675 °C, which exhibit the best ferroelectric properties and also excellent varistor-type behaviour, have been investigated in detail by TEM and x-ray diffraction. There is a partially preferred orientation of the crystallized grains of the perovskite phase along the (110) and (101) directions. During annealing, Si from the substrate diffuses into the films and forms an amorphous Si-O rich phase at the boundaries of the equiaxed grains of the perovskite phase. The formation of this amorphous phase is expected to increase the resistivity of the grain boundaries and consequently promote varistor-type behaviour. Domains were observed within the equiaxed grains and they exhibited a needle-like morphology. In a single grain, either a set of parallel domains or two sets of differently oriented parallel domains were observed. With increased diffusion of Si from the substrate, the fraction of the amorphous phase in the microstructure increased. The amorphous phase penetrated the domain boundaries within a single grain, eventually isolating the needle-like domains. The resulting microstructure consisted of needles of the perovskite phase in an amorphous matrix.

Chemistry Departmeot, University of Delhi, Delhi- II 0 007 Karimganj College, Karimganj-788 710 Manuscript received 3 March 1994, re11ised 15 December 1995, accepted 9 May 1996 Polarography of Xanthone

Department of Chemistry, University of Delhi, Delhi-110 007 Manuscript received 4 May 1993, revised 27 April 1994, accepted 28 June 1994 Polarography of 6-Methyl-4-styrylcoumarin

Department of Chemistry, University of Delhi, Delh1-llO 007 Manuscript rece1ved 3 May 1993, received 27 April1994, accepted 28 June 1994 Polarography of some Substituted Azo Derivatives

Department of Chemistry, University of Delhi, Delhi-110 007 Manuscript received 26 February 1991, revised 19 August 1991, accepted 19 March 1992 Crow's mean diffusion coefficient method applied to diffusion currents in the polarographic study of complexes of MnII CoIl NiII. CuI and ZnII with 3,6-dihydroxypyridazine yielded the following log K1 and log K2values (298 K) : MnII 7.77 2.32 ; CoII 7.20, 3 74 , NiII 6 60 4.11 , Cull 10 48, 2.67 ZnII4.85, 3.62. The overall stability constants followed Irving-Williams natural order Thermodynamic parameters ΔG, ΔH and ΔS values in the range 288 — 308 K were all negative, proving the formation of strong complexes with greater order in their molecules.&nbsp

Department of Chemistry, University of Delhi, Delhi-110 007 Manuscript received 26 September 1989, revised 28 December 1989, accepted 6 February 1990 Polarographic Study of Complexation Behaviour of β-Resorcylaldehyde with some Transition Metal Cations in Aqueous Ethanol (70%) Media

Department of Chemistry, University of Delhi, Delhi-110 007 Manuscript received 26 September 1989, revised 28 December 1989, accepted 6 February 1990 Polarographic Study of Complexation Behaviour of ��-Resorcylaldehyde with some Transition Metal Cations in Aqueous Ethanol (70%) Media

Department of Chemistry, University of Delhi, Delhi-110 007 Manuscript received 5 June 1989, revised 21 September 1989, accepted 27 October 1989 Stability constants of mixed-ligand complexes of Mnll, CoII, NiII and ZnII witho-vanillinand 4,6-dihydroxypyrimidine (70% ethanol- water media) were calculated from polarographic data using Schaap and McMasters' method. For the Mnll mixed-ligand complex, Crow's mean diffusion coefficient method was also used and the results compared well with that from the former method. Mixing, stabilisation and disproportionation constants for the mixed-ligand complexes have also been reported.

A Potassium ion-selective electrode based on dibenzo-18-crown-6-tungstophosphoric acid precipitate membrane is prepared and conditions for the best functioning have been investigated. The working concentration and pH-range of the electrode is 2.0×10−2 to 1.3×10−6 mol/l and 2.9–6.5, respectively. The selectivity coefficient values for a large number of cations are quite low except for caesium and ammonium ions. The electrode can tolerate non-aqueous content upto 20%.

It has been shown, from a study of polarograms and of the effect of pressure-head of mercury on mean current, that in alkaline solutions fluorescein undergoes reduction at the dropping-mercury electrode in two steps; the first polarographic wave is entirely diffusion-controlled, and the second is an irreversible one, each being a one-electron process. In the acidic range, a single-step irreversible reduction occurs, which has been proved to be due to competition of kinetics with diffusion. In strong acids, however, mean currents over the single polarographic wave depend approximately on the square-root of the mercury pressure, as for a reversible wave. A new method is thus available, instead of the more sophisticated techniques, to determine the nature of polarographic current–voltage curves.

A new glucoside has been isolated from the flowers ofTagetes patula. It yields by direct hydrolysis patuletin and glucose and by hydrolysis after complete methylation 3: 5: 6: 3′: 4′-O-pentamethyl quercetagetin, characterised also as its ethyl ether. The glycoside is, thus, patuletin 7-mono-glucoside and is, therefore, named patulitrin.

St. Stephen's College, Delhi-110 007 Department of Chemistry, University of Delhi, Delhi-110 007 Manuscript received 29 February 1988, revised23 May1988. accepted 1 June1988 Spectrophotometric Determination of lron(III) with Oxime, Semicarbazone and Thiosemicarbazone of 3-Methoxysalicylaldehyde &nbsp

Department of Chemistry, University of Delhi, Delhi-110 007 Manuscript received 16 April 1987, revised 6 June 1989, accepted 21 June 1989 Thermodynamic Study of Complexation of 2-Hydroxy- and 2,4-Dihydroxy-deoxybenzoins with lron(III), Copper(II), Zinc(II) and Cadmium(II)

Chemistry Department, University of Delhi, Delhi·110 007 Manuscript received 29 July 1983, revised 18 April 1984, accepted 12 August 1986 Thermodynamics of Complexation of 2,5-Dihydroxy-deoxybenzoinwith some Common Cations. &nbsp

Electrochemical Laboratories, Department of Chemistry, University of Delhi, Delhi-110 007 Manuscript received 30 September 1985, accepted 6 February 1986 The polarograms, the limiting current-pH, E1/2,-pH, limiting current-concentra­tion and slopes of log \(\bar{i}\) vs log h plots of the principal component of Datura stramonium stem., leaf- and root-extracts in cold 1% HClO4 solution prove the catalytic nature of limiting currents, similar to those of atropine. From the calibration curve (limiting current-concentration) of atropine sulphate at pH 5.3 the air-dried stems, leaves and roots of the plant are found to contain respectively 1.10, 1.05 and 1.04% of atropine.