Materials Literature
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The formation of dimers upon gamma-irradiation of thymine, thymidine and thymidine-5'-monophosphate in N2O-saturated aqueous solution is reported. A method using capillary gas chromatography-mass spectrometry was developed for their separation and identification. Quantitative measurements reveal that about 50 per cent…
Abstract The impedance of poly(pyrrole) (PP) and poly( N ‐methylpyrrole) (PMP) films on platinum in an acetonitrile, LiClO 4 solution has been measured. At potentials more positive than a characteristic value, the electrodes exhibit porous behaviour and the impedance is determined by the double‐layer capacitance and t…
The properties of the nematic-isotropic interface of the nematic liquid crystal 7CB are studied by optical reflectometry. It is found that at the interface the director is tilted with respect to the vertical axis. Measurements are reported of the tilt angle θt, of the thickness of the interface, and of the anchoring e…
Fibrils of collagen reconstituted in vitro by dialysis against sodium formate are exposed to free oxy radicals generated by three different systems: (i) xanthine oxidase + hypoxanthine, (ii) gamma-rays originating from a cobalt bomb; (iii) pulse radiolysis in a particle accelerator. A degradation of the collagen fibre…
Article Observations on Rhizosolenia clevei Ostenfeld (Bacillariophyceae) and Richelia intracellularis Schmidt (Cyanophyceae) was published on January 1, 1984 in the journal Botanica Marina (volume 27, issue 8).
2-(2-Chlorobenzoylimino)-1,3-thiazolidine (I) and 3-benzoylimino-4-methyl-1,2,4-oxathiazane (II) present short intramolecular S ⋯· O contacts of 2.68 and 2.24 Å, respectively. X-Ray and neutron diffraction at 122 K performed on (II), for comparison with (I), already studied, led to experimental charge density deformat…
Poly(4-vinylpyridine) or poly (methacrylic acid) was grafted onto an ultrathin, porous nylon capsule membrane so that permeation across the capsule membrane of NaCl trapped in the inner aqueous phase could be reversibly controlled by ambient pH changes.
Comparaison de l'utilisation, des avantages et limites des amines oxydes, ammoniac liquide avec un sel d'ammonium, et LiCl avec le dimethylacetamide comme trois des systemes solvants les plus recemment decrits
The release of Ca 2+ and OH” from tricalcium silicate into the aqueous phase was monitored over the first few hours. The solution becomes supersaturated with respect to pure calcium hydroxide with the maximum activity product being about 3.5 times greater than the solubility product. Evidence is presented in support o…
This book contains the papers given at a conference on the use of ferritic steels as reactor materials in nuclear and thermonuclear power plants. Topics considered at the conference included light water reactors (application and experience), liquid metal cooled fast breeder reactors, fusion reactor systems, non-nuclea…
Four new series of ferroelectric liquid crystals (p-alkoxybenzylidene-p′-amino-1p″-methylbutylcinnamate, p-alkoxybenzylidene-p′-amino-1p″-methylpropyl-cinnamate, o-hydroxy-p-alkoxybenzylidene-p′-amino-2p″-methylbutylcinnamate and o-hydroxy-p-alkoxybenzylidene-p′-amino-1p″-methylpropylcinnamate) have been synthesized.…
Abstract Photomicrographys of concentrated lyotropic hydroxypropylcellulose solutions confirm the cholesteric nature of the anisotropic phases in acetic acid and water. They reveal the existence of biphasic separation. Typical liquid‐crystal solvent‐dependent textures are observed. The behavior of liquid‐crystalline p…
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Mouse mammary sarcoma cells, line EMT6/Ro, were exposed for 1 min to 1 MHz continuous wave ultrasound over a range of intensities from 0.5 to 30 W/cm2 (spatial peak). The presence of thymine base damage (TBD) products of the 5,6-dihydroxydihydrothymine type was determined by an alkali degradation assay. Production of…
The structure of wermlandite, (Mg7(Alo.57Feo.43h(OH)ls)2+ ((CaO.6'Mgo.4) (S04h(H20)u)2- has been determined and refined to an R value of 7.2 % based on 779 symmetry-independent reflections, of which 224 are unobserved (weighted R=6.1%). The cell dimensions are a=b=9.303(3), c=22.57(1) A, the space group is pjc1 with Z…
The measurements of the bend (k33) and splay (k 11) elastic constants and the amplitude of the smectic-like local ordering (obtained using X-ray diffraction techniques), have been made for a wide range of nematogens. The results reveal a strong correlation between k33/k11 and the strength of the smectic-like local ord…
The dependence of the hot ductility of Al-Mg solid solution on temperature, strain rate, grain size and solute content has been examined in detail by use of tensile test. At a constant strain rate, a ductility (reduction of area) versus temperature curve showed a remarkable trough. With increase in the strain rate, th…
The effects of grinding and drying (removal of water of crystallization) processes on the solidstate stability of ampicillin trihydrate were studied. The ground samples became more unstable as the grinding time increased. This phenomenon is considered to be due to a greater freedom of movement of water molecules, whic…
The thermal transition of carbamazepine polymorphic forms (forms I, II, III) in the solid state was investigated by X-ray powder diffractometry. From the kinetic analysis according to the method of Hancock-Sharp, it appears that the transition of form I to form III follows the mechanism of random nucleation and two-di…
Abstract Thermodynamics of K exchange were investigated in Ca‐saturated samples from the Ap horizon of an Evesboro soil from Delaware. At 283 and 298 K the selectivity curves (ln k v vs. X̄ K ) showed preference for K at low values of N K (mole fraction of K in solution) and for Ca at higher values. This selectivity r…