Mihir J. Joshi

Growth and characterization of gel grown pure and mixed iron-manganese levo-tartrate crystals

Several applications of iron tartrate and manganese tartrate compounds are reported in the literature. In the present investigation, we have grown pure and mixed iron (II)-manganese levo-tartrate crystals by single diffusion gel growth technique. Crystals with spherulitic morphology were harvested. The colouration of the crystals changed from black to pinkish brown upon increasing the content of manganese in the crystals. The crystals were characterized by FTIR spectroscopy, powder XRD, TGA, VSM and dielectric study. Crystal structures of different mixed crystals were studied. From TGA it was observed that on heating the hydrated crystals became anhydrous and then converted into oxides. Paramagnetic nature of the crystals was revealed from VSM study. The variation of the dielectric constant with frequency was studied. The results are discussed.

Growth inhibition of Struvite crystals in the presence of herbal extract Commiphora wightii

Struvite is one of the components of urinary stone. Large number of people is suffering from urinary stones (calculi) problem all over the globe. These stones can grow rapidly forming “staghorn-calculi”, which is more painful urological disorder. Therefore, it is of prime importance to study the growth and inhibition of Struvite crystals. This in vitro study has been carried out in the presence of herbal extract of Commiphora wightii by using single diffusion gel growth technique. Sodium metasilicate solution of specific gravity 1.05 and an aqueous solution of ammonium dihydrogen phosphate of 0.5 M concentration were mixed so that the pH value 7.0 could be set. After the gelation, equal amount of supernatant solutions comprising of pure 1.0 M magnesium acetate as well as the mixtures of magnesium acetate and the herbal extract solutions of 0.5 and 1% concentrations of C. wightii were gently poured on the set gels. From the study of growth and inhibition behavior of Struvite crystals, it was found that C. wightii inhibits the growth of the Struvite. This study incorporates multidisciplinary interests and may be used for formulating the strategy for prevention or dissolution of urinary stones.

Inhibition of the growth of urinary calcium hydrogen phosphate dihydrate crystals with aqueous extracts of Tribulus terrestris and Bergenia ligulata

Urinary type calcium hydrogen phosphate dihydrate (CHPD) or Brushite crystals were grown by the single diffusion gel technique in silica hydro-gels. The gel framework acts as a three dimensional crucible in which the crystal nuclei are delicately held in the position of their formation and nutrients are supplied for their growth. This technique can be utilized as a simplified screening model to study the growth and dissolution of urinary stones in vitro. The action of the putatively litholytic medicinal plants Tribulus terrestris and Bergenia ligulata on the growth of CHPD crystals was studied . The effects of artificial reference urine (ARU) and human urine (HU), along with the plant extracts, are also reported. Attempts were made to understand the role of these inhibitors on urinary crystal formation. HU, ARU, extracts of B. ligulata and T. terrestris exhibit appreciable amounts of inhibition, but B.ligulata and T.terrestris with ARU and HU do not show inhibition at all.

CRYSTAL GROWTH, THERMAL, OPTICAL, AND DIELECTRIC PROPERTIES OF L-LYSINE DOPED KDP CRYSTALS

Single crystals of pure and various amount of L-lysine doped KDP crystals were grown from aqueous solution. The doping of L-lysine was confirmed by CHN analysis and FT-IR spectroscopy. Powder XRD was carried out to assess the single phase nature of the samples. The effect of doping on thermal stability of the crystals was carried out by TGA and the kinetic and thermodynamic parameters of dehydration were evaluated. It was found that as the amount of doping of amino acid, L-lysine, increased the thermal stability of the grown crystals decreased. However, the second-harmonic generation (SHG) efficiency of Nd:YAG laser and UV-vis spectroscopy studies indicated that as the L-lysine doping increased in KDP crystals the SHG efficiency and optical transmission percentage increased. The dielectric constant and the dielectric loss of L-lysine doped KDP crystals are lower than the pure KDP crystals. Hence L-lysine doped KDP crystals are found to be more beneficial from an application point of view as compared to pure KDP crystals. The results are discussed.

SYNTHESIS AND CHARACTERIZATION OF NANOPARTICLES OF CALCIUM PYROPHOSPHATE

Calcium phosphate based biomaterials play important roles in clinical applications. Calcium pyrophosphate (CPP), a kind of calcium phosphate, can be used as a bone substitution material as well as a bone graft. Because of its similarity to inorganic component of bone and teeth it can be used for surface coating of metallic dental and orthopedic implants. In the present study, calcium pyrophosphate dihydrate (CPPD) nanoparticles were synthesized using surfactant mediated approach. Crystalline nature and average crystallite size was studied using Powder XRD. The CPPD nanocrystallites were found to be triclinic from powder XRD. The TEM study indicated that CPPD nanoparticles were in the range of 13 nm to 20 nm. The presence of various bonds was confirmed by FTIR spectroscopy. The amount of water of hydration and the thermal stability was studied by thermogravimetry. The variations of various dielectric parameters with the frequency of applied field in 3.2 kHz to 32 MHz range and within a temperature range from 60°C to 120°C were studied. The formation of other phases such as β-CPP and α-CPP on heating of CPPD at 900°C and 1250°C, respectively, were studied by the Powder XRD. The results are discussed.

Vickers Micro-Hardness Studies of Amino Acids (L-Histidine, L-Threonien and DL-Methionine) Doped KDP Crystals

Pure and various amino acids (L-histidine, L-threonine, DL-methionine) doped KDP crystals were grown by slow solvent evaporation technique. The doping of amino acids was confirmed by C, H, N analysis, FTIR spectroscopy and paper chromatography .Pure and doped KDP crystals were subjected to Vickers microhardness studies. Indentations were made on smooth (100) as grown faces of pure and doped crystals. The Vickers indenter loads were varied from 0.298 N to 0.981 N in order to study the effect of load on microhardness. A number of indents were made at each load and the mean diagonal length (d) was used in calculating the Vickers Hardness Number (HV). The Vickers micro-hardness decreased as amino acid doping level was increased indicating that the KDP crystals became softer after doping. The Indentation size effect (ISE) the Kicks law as well as PSR model was verified for all samples. The values of the load independent hardness and the Newtonian pressure (W) were higher in pure KDP crystals than the amino acids doped KDP crystals. It was found that as the doping concentration of amino acids increased the values of load independent hardness and Newtonian pressure decreased. Hays and Kendall law analysis was also applied to the hardness data.

Knoop hardness studies on anthracene single crystals

AbstractKnoop microhardness studies were carried out on anthracene single crystals. The hardness vs load plot shows two peaks, one at 5g and another at 17·5 g having hardness values 13·0 kg/mm2 and 11·4 kg/mm2 respectively. The present observation shows that the

Synthesis and Characterization of Cholesterol Nano Particles by Using w/o Microemulsion Technique

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