Effect of semi-solid forging on microstructure and mechanical properties of in-situ cast Al-Cu-TiB2 composites

The present work deals with the effect of semisolid processing on microstructure and mechanical properties of Al-4.5% Cu – 5% TiB2 in-situ cast composites. The composite was prepared by flux assisted synthesis in which TiB2 particles were formed in-situ through an exothermic reaction between K2TiF6 and KBF4 halide salts. Al-4.5 wt% Cu alloy and Al-4.5% Cu-5% TiB2 composite samples were forged in semisolid state with 0.3 vol fraction of liquid. Semisolid forging was carried out for two forge reductions (30% and 50% forge reductions). Microstructure studies show that the semi-solid forging results in uniform distribution of TiB2 particles and Al2Cu particles in the composite. Further, TiB2 particles play a dual role as grain refiners as well as reinforcements of composites. EBSD and nano indentation studies shows that semisolid forging results in dynamic recrystallization of grains in the composite with significant grain refinement which leads to a marked increase in hardness and elastic modulus of the alloy as well as the composite

Correlation of serum androgen and gonadotropin with anti-mullerian hormone in polycystic ovarian syndrome in Eastern Indian population

Background: Ovarian steroidogenesis requires gonadotropin stimulation, Luteinizing Hormone (LH) is a key factor in the hyperandrogenaemia of the polycystic ovary syndrome. Progesterone is the primary regulator of Gonadotropin-Releasing Hormone (GnRH) pulse frequency; however, in the polycystic ovary syndrome, the GnRH pulse generator is relatively resistant to the negative feedback effects of progesterone.  Study aims to evaluate the association of Anti-mullerian hormone with serum androgen and gonadotropin level in adolescents and young women of Polycystic Ovary Syndrome (PCOS).Methods: This was a single centre observational Cross-sectional study carried out in the department of Endocrinology and metabolism, Medical College, Kolkata from March 2017 to January 2019. Total number of study subjects were 207 out of which 138 were cases.Results: The AMH had strong positive correlation with serum testosterone in both case and control groups (r 0.542, p<0.001 and r 0.57, p<0.001) respectively .After the adjustment of age and BMI , the AMH moderately positive  but extremely significant correlation with serum testosterone as compare to control.Conclusions: Hyperandrogenaemia and higher ratio of LH and FSH associated with higher serum AMH level is associated with the higher serum AMH in polycystic ovarian syndrome

Geometrical isomers of <i>ortho-</i>substituted bis(triazene 1-oxide) chelates of palladium(II)

675-677Bis(1-methyl-3(o-tolyl)triazene-1-oxido)palladium(II) (PdL2), has been synthesized from Na2PdCl4 and HL and chromatographically separated into trans and cis forms which have been structurally characterized. The trans isomer is centrosymmetric. The chelate rings are excellently planar in both isomers. The pendent aromatic rings in the cis isomer make a dihedral angle of only 15.6° suggesting the presence of some π – π interaction between them. Upon melting the cis isomer it is spontaneously converted to the trans form

Thioether binding of manganese oxidation states. Chemistry of an MnII,IIIS<SUB>2</SUB>N<SUB>2</SUB>O<SUB>2</SUB> family

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Activation of chelated thioethers by base. Ring-size-specific transformations of salicylaldimine-substituted dithiaalkanes bonded to trivalent cobalt

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Hexacoordinated complexes of bivalent zinc incorporating thioether binding

The reaction of zinc(II) acetate dihydrate with dithiaalkyl-substituted triazene 1-oxides, [RN(O)NNHC<SUB>6</SUB>H<SUB>4</SUB>S]<SUB>2</SUB>(CH<SUB>2</SUB>)<SUB>2</SUB> (H<SUB>2</SUB>RL; R=Me, Ph) has afforded light-yellow Zn(MeL) and light-green Zn(PhL) . &#189; CH<SUB>2</SUB>Cl<SUB>2</SUB>, the first hexacoordinated of zinc bonded by acyclic ligands incorporating thioether sites. Spectral features ff the complexes are briefly noted. Both the complexes have been structurally characterized revealing distorted octahedral binding of the metal ion in ZnO<SUB>2</SUB>N<SUB>2</SUB>S<SUB>2</SUB> coordination spheres; the Zn---O, Zn---N and Zn---S distances lie in the ranges 2.056(7)-2.105(8), 2.005(8)-2.029(8) and 2.649(4)-2.720(3) &#197;, respectively. Crystal data: Zn(MeL): monoclinic, space group P2<SUB>1</SUB>/c, a = 26.529(9), b = 7.974(3), c = 19.396(8) &#197;, &#946; = 110.57(3)&#176;, V = 3842(3) &#197;<SUP>3</SUP>, Z = 8, R = 5.40%, R<SUB>w</SUB> = 5.73%; ; orthorhombic, space group Pbcb, a = 9.540(3), b = 19.449(6), c = 29.534(8) &#197;, V = 5480(3) &#197;<SUP>3</SUP>, Z = 8, R = 5.65%, R<SUB>w</SUB> = 5.42%

Ring-size specific transformations of cobalt(III)-thioether chelates activated by base. Co-C formation or C-S cleavage?

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