Separation of Pt(IV) from Industrial Wastewater Using Rice Husk Adsorbent and Its Derivatives

Some novel adsorbents were prepared by rice husk (RH). The esterified rice husk (RHS) was prepared by treating RH with anhydride of succinic acid to introduce carboxylic function to rice husk. This RHS was used to anchor various polyamines, viz., ethylenediamine (ED) and diethylenetriamine (DT) to prepare new adsorbents. These adsorbents were used to separate Pt(IV) from synthetic as well as industrial wastewaters. Adsorbents were characterized by Fourier transform infrared spectra, elemental analysis, scanning electron microscopy, and energy dispersive x-ray spectrometry. The selectivity order for Pt(IV) removal found was: RHS-DT > RHS-ED > RH > RHS. The Freundlich isotherm provided the high correlation (0.9750–0.9938) for the adsorption with low SSE (0.00215–0.00785) value of Pt(IV) for all the adsorbents. Among the kinetic models, pseudo-second order kinetic model was found to best fit with high correlation for all the adsorbents. The results of thermodynamic parameters suggest that the Pt(IV) adsorption was spontaneous and endothermic in nature. The maximum percentage of desorption of Pt(IV) metal ion was obtained when the reagent HCl–thiourea mixture was used as desorbing agent.     

Separation of 90Y from 90Sr using sequential multiple column extraction chromatography

The distribution coefficient measurements on Y(III) and Sr(II) were performed using ditertiarybutyl dicyclohexano 18-crown-6 (Sr-selective resin) and N,N,N′,N′-tetraoctyldiglycolamide (Y-selective resin) in HNO₃, HCl and HClO₄ media. Separation factors (⁹⁰Y/⁹⁰Sr) based on distribution coefficient data suggested that perchloric acid is distinctly better medium as compared to nitric acid/hydrochloric acid. The mechanism of extraction changes with the nature and concentration of acid and is responsible for the high selectivity in perchloric acid medium. Sequential column studies were carried out on tracers (radioactive/stable) employing Sr-selective/Y-selective extraction chromatographic resins as stationary phases. The final elution of ⁹⁰Y was done in 0.01 M EDTA at pH 4.0 which can be used for clinical applications after radiochemical processing.     

Differentiability of Intrinsic Lipschitz Functions within Heisenberg Groups

We study the notion of intrinsic Lipschitz graphs within Heisenberg groups, focusing our attention on their Hausdorff dimension and on the almost everywhere existence of (geometrically defined) tangent subgroups. In particular, a Rademacher type theorem enables us to prove that previous definitions of rectifiable sets in Heisenberg groups are natural ones.     

Sculptured 3D twister superlattices embedded with tunable vortex spirals

We present diverse reconfigurable complex 3D twister vortex superlattice structures in a large area embedded with tunable vortex spirals as well as dark rings, threaded by vortex helices. We demonstrate these tunable complex chiral vortex superlattices by the superposition of relatively phase engineered plane waves. The generated complex 3D twister lattice vortex structures are computationally as well as experimentally analyzed using various tools to verify the presence of phase singularities. Our observation indicates the application-specific flexibility of our approach to tailor the transverse superlattice spatial irradiance profile of these longitudinally whirling vortex-cluster units and dark rings.     

Synthesis and catalytic properties of nanoparticulate intermetallic Ga-Pd compounds

A two-step synthesis for the preparation of single-phase and nanoparticulate GaPd and GaPd(2) by coreduction of ionic metal-precursors with LiHBEt(3) in THF without additional stabilizers is described. The coreduction leads initially to the formation of Pd nanoparticles followed by a Pd-mediated reduction of Ga(3+) on their surfaces, requiring an additional annealing step. The majority of the intermetallic particles have diameters of 3 and 7 nm for GaPd and GaPd(2), respectively, and unexpected narrow size distributions as determined by disk centrifuge measurements. The nanoparticles have been characterized by XRD, TEM, and chemical analysis to ensure the formation of the intermetallic compounds. Unsupported nanoparticles possess high catalytic activity while maintaining the excellent selectivity of the ground bulk materials in the semihydrogenation of acetylene. The activity could be further increased by depositing the particles on α-Al(2)O(3).     

Design,synthesis, pharmacological evaluation and in silico ADMET prediction of novel substituted benzimidazole derivatives as angiotensin II–AT1 receptor antagonists based on predictive 3D QSAR models

In this study we designed novel substituted benzimidazole derivatives and predicted their absorption, distribution, metabolism, excretion and toxicity (ADMET) properties, based on a predictive 3D QSAR study on 132 substituted benzimidazoles as AngII–AT₁ receptor antagonists. The two best predicted compounds were synthesized and evaluated for AngII–AT₁ receptor antagonism. Three different alignment tools for comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were used. The best 3D QSAR models were obtained using the rigid body (Distill) alignment method. CoMFA and CoMSIA models were found to be statistically significant with leave-one-out correlation coefficients (q²) of 0.630 and 0.623, respectively, cross-validated coefficients (r²_cv) of 0.651 and 0.630, respectively, and conventional coefficients of determination (r²) of 0.848 and 0.843, respectively. 3D QSAR models were validated using a test set of 24 compounds, giving satisfactory predicted results (r²_pred) of 0.727 and 0.689 for the CoMFA and CoMSIA models, respectively. We have identified some key features in substituted benzimidazole derivatives, such as lipophilicity and H-bonding at the 2- and 5-positions of the benzimidazole nucleus, respectively, for AT₁ receptor antagonistic activity. We designed 20 novel substituted benzimidazole derivatives and predicted their activity. In silico ADMET properties were also predicted for these designed molecules. Finally, the compounds with best predicted activity were synthesized and evaluated for in vitro angiotensin II–AT₁ receptor antagonism.     

FTIR and thermal studies of gel-grown,lead–cadmium-mixed levo tartrate crystals

Metal tartrate compounds find various applications. Lead tartrate is added in gasoline to prevent knocking in motors, and cadmium tartrate crystals possess piezoelectric nature. In the present study, lead–cadmium-mixed levo tartrate crystals were grown using silica hydro gel as growth medium. Long and dendrite-type white crystals were obtained. The crystals were characterized by EDAX, powder XRD, FTIR spectroscopy, TG, DTA, and DSC. The composition of the crystals was determined by EDAX. The FTIR spectra revealed the presence of water molecules, O–H, C–H, C–O, C–C, and C=O functional groups. TG curves suggested that the crystals were thermally unstable and decomposed into oxide through three stages. DTA curves showed endothermic and exothermic reactions.     

q-Extensions of certain Erdélyi type integrals

Recently we discovered several new Erdélyi type integrals. In the present paper, it is shown how the q-extensions of all those integrals involving and representing certain q-hypergeometric functions can be developed. The well-known special cases and applications of these q-integrals are also pointed out.     

DIFFERENTIAL EFFECT OF ULTRAVIOLET-B RADIATION ON CERTAIN METABOLIC PROCESSES IN A CHROMATICALLY ADAPTING Nostoc

The impact of UV-B radiation on growth, pigmentation and certain physiological processes has been studied in a N2-fixing chromatically adapting cyanobacterium, Nostoc spongiaeforme. A brownish form (phycoerythrin rich) was found to be more tolerant to UV-B than the blue-green (phycocyanin rich) form of N. spongiaeforme. Continuous exposure to UV-B (5.5 W m-2) for 90 min caused complete killing of the blue-green strain whereas the brown strain showed complete loss of survival after 180 min. Pigment content was more strongly inhibited in the blue-green strain than in the brown. Nitrogenase activity was completely abolished in both strains within 35 min of UV-B treatment. Restoration of nitrogenase occurred upon transfer to fluorescent or incandescent light after a lag of 5-6 h, suggesting fresh synthesis of nitrogenase. Unlike the above processes, in vivo nitrate reductase activity was stimulated by UV-B treatment, the degree of enhancement being significantly higher in the blue-green strain. Like the effect of UV-B on nitrogenase, 14CO2 uptake was also completely abolished by UV-B treatment in both strains. Our findings suggest that UV-B may produce a deleterious effect on several metabolic activities of cyanobacteria, especially in cells lacking phycoerythrin. Strains containing phycoerythrin appear to be more tolerant to UV-B, probably because of their inherent property of adapting to a variety of light qualities.     

On the Gravitational Instability of an Ionized Magnetized Rotating Plasma Flowing Through a Porous Medium with other Transport Processes and the Suspended Particles

The effects of suspended particles and the finite thermal and electrical conductivities on the magnetogravitational instability of an ionized rotating plasma through a porous medium have been investigated, under varying assumptions of the rotational axis and the modes of propagation. In all the cases it is observed that the Jeans' criterion determines the condition of instability with some modifications due to various parameters. The effects of rotation, the medium porosity, and the mass concentration of the suspended particles on instability condition have been removed by (1) magnetic field for longitudinal mode of propagation with perpendicular rotational axis, and (2) viscosity for transverse propagation with rotational axis parallel to the magnetic field. The mass concentration reduces the effects of rotation. Thermal conductivity replaces the adiabatic velocity of sound by the isothermal one, whereas the effect of the finite electrical conductivity is to delink the alignment between the magnetic field and the plasma. Porosity reduces the effects of both the magnetic field and the rotation, on Jeans' criterion.