B. B. Parekh

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.

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.

Growth and characterization of L-tryptophan doped KDP crystals

Potassium Dihydrogen Phosphate crystals are one of the most popular crystals used for Non-linear Optical applications. Most of the amino acids also exhibit NLO properties. The effect of doping of one of the amino acids, L-tryptophan in KDP crystals has been investigated. Pure and L-tryptophan doped KDP crystals were grown by slow solvent evaporation solution growth technique. Good quality transparent crystals were obtained. Doping of L-tryptophan in KDP crystal was confirmed by FT-IR spectroscopy studies. The value of second harmonic generation efficiency and optical transmission in UV-Vis spectra increased as doping of L-tryptophan increased in KDP crystals.

Powder XRD and dielectric studies of gel grown calcium pyrophosphate crystals

Formation of calcium pyrophosphate dihydrate (CPPD) crystals in soft tissues such as cartilage, meniscus and synovial tissue leads to CPPD deposition diseases. The appearance of these crystals in the synovial fluid can give rise to an acute arthritic attack with pain and inflammation of the joints, a condition called pseudo-gout. The growth of CPP crystals has been carried out, in the present study, using the single diffusion gel growth technique, which can broadly mimic in vitro the condition in soft tissues. The crystals were characterized by different techniques. The FTIR study revealed the presence of various functional groups. Powder XRD study was also carried out to verify the crystal structure. The dielectric study was carried out at room temperature by applying field of different frequency from 500 Hz to 1 MHz. The dielectric constant, dielectric loss and a.c. resistivity decreased as frequency increased, whereas the a.c. conductivity increased as frequency increased.