Synthesis and spectral studies of polyamide-phosphate esters from phosphine-oxide-containing diols with aryl phosphorodichloridates and their thermal and flammability behaviour

Polyamide-phosphate esters were synthesized by interfacial polycondensation of aryl phosphorodichloridates with the diols of phenoxaphosphine and phosphine oxide in the presence of a phase-transfer catalyst. The polymers were characterized by infra-red and 1H, 13C and 31P nuclear magnetic resonance (n.m.r.) spectroscopy. The molecular weights were determined by end-group analysis using 31P n.m.r. spectral data. The phenoxaphosphine-containing polymers showed superior thermostability and flame retardancy over the phosphine-oxide-containing polymers.

Inhibition of rat liver mevalonate pyrophosphate decarboxylase and mevalonate phosphate kinase by phenyl and phenolic compounds.

1. Mevalonate pyrophosphate decarboxylase of rat liver is inhibited by various phenyl and phenolic acids. 2. Some of the phenyl and phenolic acids also inhibited mevalonate phosphate kinase. 3. Compounds with the phenyl-vinyl structure were more effective. 4. Kinetic studies showed that some of the phenolic acids compete with the substrates, mevalonate 5-phosphate and mevalonate 5-pyrophosphate, whereas others inhibit umcompetitively. 5. Dihydroxyphenyl and trihydroxyphenyl compounds and p-chlorophenoxyisobutyrate, a hypocholesterolaemic drug, had no effect on these enzymes. 6. Of the three mevalonate-metabolizing enzymes, mevalonate pyrophosphate decarboxylase has the lowest specific activity and is probably the rate-determining step in this part of the pathway.

Structure of disocium uridine 5'-Phosphate heptahydrate

Na2[CgHllN2OgP].7H20, M r = 494.0,orthorhombic, C222~, a = 22.880 (7), b = 8.877 (3),c = 19.592 (9) A, Z = 8, V = 3979.2 A 3. The Cu Ka intensity data consisted of 1005 unique reflections. Final R -- 14.5%. This nucleotide shows no unusual conformational features. The uracil base has an anti conformation about the glycosidic bond (tpo o = 44.4°). The furanose ring conformation is C(2')-endo,gauchegauche with tpo o = -75.5 ° and ~Poc = 49"6°.

Coupled substitution of niobium and silicon in potassium titanyl phosphate and arsenate (KTiOPO4 and KTiOAsO4. Synthesis and nonlinear optical properties of KTi1-xNbxOX1-xSixO4 (X = P, As)

Coupled substitution of Nb(V) and Si(IV) for Ti(IV) and P(V)/As(V) in KTiOP04 (KTP) and KTiOAsO4 (KTA) giving new series of nonlinear optical materials, KTi1-xNbxOX1-xSixO4 (X=P,As), has been investigated. Substitution up to x = 0.40 readily occurs, the members retaining the orthorhombic (Pna2(1)) structure of KTP. The second harmonic generation (SHG) property of the parent KTP and KTA is not adversely affected by the coupled substitution. SHG intensity of the powder samples of the X = P series shows a slight increase with x up to x = 0.15; for 0.15 < x less-than-or-equal-to 0.40, there is a decrease in SHG intensity as compared to that for KTP. A similar trend in SHG intensity is seen for the arsenic analogs.

Inverse relationship of the dehydrogenase and ADP-ribosylation activities in sodium-nitroprusside-treated glyceraldehyde-3-phosphate dehydrogenase is coincidental

Incubation of glyceraldehyde-3-phosphate dehydrogenase (GAPD) with sodium nitroprusside (SNP) decreased its activity in concentration- and time-dependent fashion in the presence of a thiol compounds, with DTT being more effective than GSH. Both forward and backward reactions were effected. Coinciding with this, HgCl2-sensitive labelling of the protein by [32P]NAD+ also increased, indicating the stimulation of ADP-ribosylation. Treatment with SNP of GAPD samples from rabbit muscle, sheep brain and yeast inactivated the dehydrogenase activity of the three, but only the mammalian proteins showed ADP-ribosylation activity. The SNP-modified protein of rabbit muscle GAPD, freed from the reagent by Sephadex filtration showed a concentration-dependent restoration of the dehydrogenase activity on preincubation with DTT and GSH. Such thiol-treated preparations also gave increased ADP-ribosylation activity with DTT, and to a lesser extent with GSH. The SNP-modified protein was unable to catalyze this activity with the native yeast enzyme and native and heat-inactivated muscle enzyme. It was possible to generate the ADP-ribosylation activity in muscle GAPD, by an NO-independent mechanism, on dialysis in Tris buffer under aerobic conditions , and on incubating with NADPH, but not NADH, in muscle and brain, but not yeast, enzymes. The results suggest that the inverse relationship of the dehydrogenase and ADP-ribosylation activities is coincidental but not correlated

An unusual distribution of glucose-6-phosphate dehydrogenase deficiency of south Indian newborn population.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is seen at a higher frequency in many national and ethnic groups in areas of current or former malaria endemicity. A screening programme undertaken to evaluate the gene frequencies for this deficiency in the highly inbred South Indian population of Karnataka revealed that of the 5140 neonates screened, 7.8% were G6PD deficient with no correlation between the reported level of inbreeding and enzyme deficiency. An interesting finding was the equal number of male (198) and female (207) individuals, with G6PD activity of less than 3 IU. The possible implications of this finding with regard to the expression of G6PD gene is discussed.

Ball wear mechanisms and control in the grinding of sulfide and phosphate ores

Marked ball grinding tests were carried out in the laboratory using high carbon low alloy steel (cast and forged) and high chrome cast iron balls. Relative ball wear as a function of grinding period and milling conditions was evaluated for the different type of ball materials in the grinding of lead-zinc sulphide and phosphate ores. Results indicated that ball wear increased with time and showed a sharp increase for wet grinding over dry grinding. Ball wear under wet grinding conditions was also influenced by the gaseous atmosphere in the mill. The influence of oxygen on the corrosive wear of grinding balls was increasingly felt in case of sulphide ore grinding. The grinding ball materials could be arranged in the following order with respect to their overall wear resistance:

Characterization of a variant glucose-6-phosphate dehydrogenase from the south Indian population.

Glucose-6-phosphate dehydrogenase (G6PD) is coded by a gene on the X-chromosome. Earlier studies have shown that the South Indian population has a high incidence of this enzyme deficiency. The electrophoretic mobility, pH optimum and the K-m values for G6PD from normal and variant individuals were identical. However, the specific activity of the variant enzyme was 8 times less compared to the value of the normal enzyme. Western blot analysis of partially purified G6PD from normal and variant individuals performed using equal amounts of total protein showed that the variant protein was 3 times less in concentration. Similar analysis performed using protein corresponding to equal enzyme activity units in the normal and variant samples showed that the variant enzyme was 2.25 times less efficient compared to the normal enzyme. RNA dot blot analysis using full length G6PD cDNA probe (PGDT5B, a kind gift from Prof. L Luzzatto) revealed that lymphocytes from normal and variant individuals had equal amounts of G6PD specific mRNA.

Effects of halogen substitution in nucleic acid components. Structure of sodium 5-bromocytidine 5'-phosphate hydrate

The conformation of 5-bromocytidine 5'-monophosphate in the title compound, Na+.C9H11BrN3O8P-.1.25H2O, is anti, C(3')-endo and gauche-gauche, similar to that in analogous non-halogenated nucleosides/nucleotides. The Na ion coordinates directly with phosphate O atoms and base atoms. Br is not involved in any stacking interaction.

A method for in vivo [32P]phosphate labelling of testis proteins

The direct intratesticular injection of [P-32]phosphate resulted in 4-9 times more labelling of rat testis proteins compared to the conventional method of in vitro incubation. Moreover this is a simple technique requiring minimum (7-10 times less) radioactive phosphate and is less hazardous.

Effect of phosphate adsorption on the permeability of clays

In this paper, the effect of phosphate anion adsorption on the permeability values of homoionized kaolinite and montmorillonite clays is presented. The homoionized sodium, calcium and hydrogen clays are prepared by repeatedly washing the clays with 2N solutions of corresponding chlorides. Phosphate adsorption was induced by treating homoionized clays with phosphoric acids for different periods varying upto 1000 hrs. The coefficient of permeability of the clays was determined from one dimensional consolidation test results. The decrease in the permeability of kaolinite clays on phosphate adsorption has been explained on the fabric changes. For montmorillonite, both cation exchange and phosphate adsorption causes significant changes which are explained based on variation in the thickness of diffuse double layer.

Insertion of nickel nanoparticles in the interlayers of alpha-zirconium phosphate by the decomposition of the intercalated nickel acetate

By employing EXAFS and magnetic measurements, it is shown that nanoparticles of nickel along with those of NiO are incorporated between the layers of a-zirconium phosphate (ZrP) by the thermal decomposition of nickel acetate intercalated in ZrP. The nickel nanoparticles are superparamagnetic. Hydrogen reduction produces small ferromagnetic nickel particles, most of which appear to be outside the interlayer space of ZrP.