Effect of cost-free energy storage material and saline water depth on the performance of square pyramid solar still: a mathematical and experimental study

Journal of Thermal Analysis and Calorimetry - Low productivity of single-slope solar still is the main barrier for its worldwide usability. An attempt has been conducted to enhance the distillate...     

Efficient implementation of Jacobi's diagonalization method on the DAP

Summary The DAP architecture brings into consideration the Jacobi method where several non-interacting rotations can be performed in parallel. However the design of the algorithm is crucial in a parallel environment. In this paper we shall consider two techniques specifically designed to reduce the organisation and the arithmetic components of the parallel Jacobi method.     

A new synthesis of aldehydes from acids via reduction of N-acyl saccharins using sodium dihydro bis-(2-methoxy-ethoxy) aluminate

Synthesis of certain aldehydes from the carboxylic acids has been carried by reduction of the corresponding N-acyl saccharins using SDA. The N-acyl saccharins are easily prepared by reaction of an acid with γ-saccharin chloride, which can be used for the next step of reduction without isolation and purification. This provides a convenient and one step synthesis of aldehydes by combining the two reactions, viz., preparation of the N-acyl compound and its reduction. The method has been successfully applied for the reduction of aliphatic, alicyclic, aromatic, and a α,β-unsaturated acids to the corresponding aldehydes and the yields obtained are quite satisfactory.     

Swift heavy ion irradiation-induced modifications in structural and electrical properties of Y3+-substituted yttrium iron garnet

The consequences of 50 MeV Li³⁺ ion irradiation (fluence: 5×10¹³ ions/cm²) on the structural and electrical properties of the Y_3+xFe_5?xO₁₂ (x=0.0, 0.2, 0.4 and 0.6) garnet system have been investigated over the temperature range of 300–673 K. It is found that the percentage formation of an additional yttrium orthoferrite phase observed along with the bcc garnet phase considerably reduces for x=0.4 and 0.6 compositions after swift heavy ion (SHI) irradiation. The nature of thermal variation of DC resistivity curves for x=0.0 and 0.2 compositions is different from that for x=0.4 and 0.6 compositions. The SHI irradiation influences the magnitude of DC resistivity and conduction mechanism for the single-phase compositions while for mixed-phase compositions they remain unaffected. The results have been explained in the light of replacement of magnetic (5μ_B), smaller (0.64 Å), Fe³⁺ ion by nonmagnetic (0μ_B), larger (0.89 Å), Y³⁺ ion, the presence of the yttrium orthoferrite phase and swift heavy ion irradiation-induced paramagnetic centers in the system.     

A review on iron chelators as potential therapeutic agents for the treatment of Alzheimer’s and Parkinson’s diseases

Iron plays a vital role in several cellular functions due to its unique physiochemical properties. Iron concentration increases in the brain with age due to multiple factors. Excessive amount of iron can lead to formation of reactive oxygen species. Neurodegenerative disorders are characterized by iron supplemented increase in oxidative stress and cellular damage. There is an urgent need of novel therapies which should not only provide symptomatic relief but also be able to modulate iron accumulation in the brain. Therefore, the development of novel iron chelators as neuroprotective agents for the treatment of neurodegeneration is an emerging trend. Several iron chelators including 8-hydroxyquinoline derivatives, dopaminergic agonists and natural products are under preclinical and clinical investigations for the treatment of neurodegenerative disorders.

     

Monitoring carbohydrate enzymatic reactions by quantitative in vitro microdialysis

On-line in vitro microdialysis (MD) sampling followed by HPLC separation and UV absorbance detection (HPLC-UV) was used to monitor carbohydrate enzyme systems. Fundamental parameters (i.e., K(m) and V(max)) of hydrolysis reactions of 4-nitrophenyl-beta-D-glucopyranoside, 4-nitrophenyl-beta-d-galactopyranoside, and 4-nitrophenyl-beta-D-xylopyranoside were determined for a model enzyme, almond beta-glucosidase. Accurate quantitation was achieved via internal standard methodology and compared to spectrophotometric data and literature K(m) values, which were found to be 2.6+/-0.5 mM (MD), 2.7+/-0.4 mM (spec), and 2.5 mM (lit), for the substrate 4-nitrophenyl-beta-d-glucopyranoside. A previously unpublished K(m) value for the substrate salicin was also determined by this method. An application is shown for monitoring the glycoside salicin and its hydrolysis product saligenin in a commercially available willow bark product that is used for making tea. This versatile method has far-reaching applications to monitoring a variety of carbohydrates in enzymatic processes without complex sample preparation procedures and without volume loss.     

Transition metal complexes enslaved in the supercages of zeolite-Y: DFT investigation and catalytic significance

A series of zeolite-Y encapsulated hybrid catalysts, [M(STCH)·xH₂O]-Y have been prepared by encapsulating Schiff base complexes [where M?=?Mn(II), Fe(II), Co(II), Ni(II); (x?=?3) and Cu(II); (x?=?1); H₂STCH?=?salicylaldehyde thiophene-2-carboxylic hydrazone] in zeolite-Y matrix by flexible ligand method. These hybrid materials have been characterized by various physico-chemical techniques such as ICP-OES, elemental analyses, (FT-IR and electronic) spectral studies, BET, scanning electron micrographs, thermal analysis and X-ray powder diffraction patterns. X-ray powder diffraction analysis reveals that the structural integrity of the mother zeolite in the hybrid material remained intact upon immobilization of the complex. Density functional theory is employed to calculate the relaxed structure, bond angle, bond distance, dihedral angle, difference of highest occupied molecular orbital and lowest unoccupied molecular orbital energies gap and electronic density of states of ligand and their neat transition metal complexes. The hybrid materials are active catalysts for the hydroxylation of phenol using hydrogen peroxide (30% H₂O₂) as an oxidant in order to selectively synthesize catechol or hydroquinone, amongst them [Cu(STCH)·H₂O]-Y shown the highest % of selectivity towards catechol (81.3%).     

Calix[4]arene based 1,3,4-oxadiazole and thiadiazole derivatives: design, synthesis, and biological evaluation

In the present investigation, we describe some novel calixarene based heterocyclic compounds (5a-5i) in which 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives have been coupled with 5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxy calix[4]arene. All the newly synthesized calixarene based heterocyclic compounds have been characterized by elemental analysis and various spectroscopic methods like FTIR, (1)H NMR, (13)C NMR, and FAB-MS. All the final scaffolds have been subjected to antioxidant activity, in vitro antimicrobial screening against two gram (+ve) bacteria (S. aureus, S. pyogenes), two gram (-ve) bacteria (E. coli, P. aeruginosa) and two fungal strains (C. albicans, A. clavatus) and also have been screened for their antitubercular activity against Mycobacterium tuberculosis H(37)Rv.