Photochemistry of desonide, a non-fluorinated steroidal anti-inflammatory drug

The photochemistry of anti-inflammatory drug desonide (De, 1) was studied in aerobic as well as in anaerobic condition with different irradiation wavelengths (254, 310 nm) in acetonitrile and 2-propanol. All photoproducts obtained were isolated and characterized on the basis of IR, (1)H-, (13)C-NMR spectroscopy and elemental analysis study. The products were: 11beta,21-dihydroxy-16alpha,17alpha-(1-methylethylidenedioxy)-1,5-cyclopregn-3-ene-2,20-dione 2 (254 nm), 11beta-hydroxy-16alpha,17alpha-(1-methylethylidenedioxy)androsta-1,4-diene-3-one 3 (310 nm/2-propanol), 17beta-hydroperoxy-11beta-hydroxy-16alpha,17alpha-(1-methylethylidenedioxy)androsta-1,4-diene-3-one 4 (310 nm/O(2)/2-propanol). Cyclohexadienone moiety in ring A and keto group at C(17) were found to be deeply modified by UV light therefore, loss of biological activity both during storage and in vivo can not be ruled out.     

A simple and efficient approach to 1,3-polyols: application to the synthesis of cryptocarya diacetate

A highly enantio- and stereoselective synthetic strategy for both syn- and anti-1,3-polyols has been developed. The sequence involves iterative Jacobsen's hydrolytic kinetic resolution (HKR), diastereoselective iodine-induced electrophilic cyclization, and ring-closing metathesis (RCM). This protocol has subsequently been utilized for the synthesis of cryptocarya diacetate, a natural product with broad range of biological activity.     

Adsorption of Safranin-T from wastewater using waste materials- activated carbon and activated rice husks

Textile effluents are major industrial polluters because of high color content, about 15% unfixed dyes and salts. The present paper is aimed to investigate and develop cheap adsorption methods for color removal from wastewater using waste materials activated carbon and activated rice husk-as adsorbents. The method was employed for the removal of Safranin-T and the influence of various factors such as adsorbent dose, adsorbate concentration, particle size, temperature, contact time, and pH was studied. The adsorption of the dye over both the adsorbents was found to follow Langmuir and Freundlich adsorption isotherm models. Based on these models, different useful thermodynamic parameters have been evaluated for both the adsorption processes. The adsorption of Safranin-T over activated carbon and activated rice husks follows first-order kinetics and the rate constants for the adsorption processes decrease with increase in temperature.     

Optical sensing of parts per million levels of water in organic solvents using redox-active osmium chromophore-based monolayers

Optical sensing of parts per million (ppm)-levels of H2O (10-300 ppm) in an organic solvent with robust, osmium chromophore-based monolayers is demonstrated. The H2O-induced reduction of the covalently bound osmium(III) complex is fully reversible and can be readily monitored by UV/vis absorption spectroscopy. The thermally robust sensor can be reactivated chemically within 3 min.     

Screening of domperidone in wastewater by high performance liquid chromatography and solid phase extraction methods

Domperidone is a dopamine D₂ receptor antogonist, which has been used as antiemetic agent in human beings. It has been found in wastewater released by some pharmaceutical industries leading to the contamination of surface and ground water. Therefore, a sensitive, inexpensive and reproducible HPLC-SPE method was developed for the analysis of domperidone in the wastewater. The column used was Waters symmetry C₁₈ (15 cm × 0.46 mm, 5 μm). The mobile phase used was phosphate buffer (50 mM, pH 3.5) acetonitrile (80:20, v/v) at the flow rate 2.0 mL/min. The detection was achieved by using UV mode at 230 nm. The retention, separation and resolution factors were 2.63, 3.00 and 3.20, respectively. The percentage recovery of domperidone from wastewater was 95.0%. Celiprolol was used as the internal standard to access the percentage extraction of domperidone from wastewater.     

Oxo- and oxoperoxo-molybdenum(VI) complexes with aryl hydroxamates: synthesis, structure, and catalytic uses in highly efficient, selective, and ecologically benign peroxidic epoxidation of olefins

A solution obtained by dissolving MoO3 in H2O2 reacts separately with secondary hydroxamic acids (viz., N-benzoyl N-phenyl hydroxamic acid (BPHAH), N-benzoyl N-ortho-, -meta-, -para-tolyl hydroxamic acids, (BOTHAH, BMTHAH, and BPTHAH, respectively), and N-cinnamoyl N-phenyl hydroxamic acid (CPHAH) affording [MoO(O2)(BPHA)2] (1), [MoO(O2)(BOTHA)2] (2), [MoO(O2)(BMTHA)2] (3), [MoO(O2)(BPTHA)2] (4), and [Mo(O)2(CPHA)2](5), respectively. The O and O2 are situated cis to each other in 2-4, but in each case, they are disordered and distributed over four sites. This disorder does not exist in the 6-coordinate cis dioxo complex 5, to which crude MoO(O2)(CPHA)2 (5') was converted during recrystallization. An aqueous molybdate solution readily reacts with all those hydroxamic acids producing [Mo(O)2(hydroxamate)2] (6). While 2, 3, and 4 possess a very distorted pentagonal bipyramidal structure, 5 has a distorted octahedral geometry. In the solid state, as well as in solution, 5 exists as two apparently enantiomerically related molecules differing in the orientation of the pendant phenyl rings. To emphasize that the formation and structural uniqueness of 5 compared to 1-4 is caused by the influence of the cinnamoyl residue, one compound of the 6 series, namely, [Mo(O)2(BPHA)2] (6A), was structurally characterized to prove directly that the special stereochemical properties of 5 rely on the special electronic structure of CPHA- ligand. Complexes 1-5, as well as 6, show high potential and selectivity as catalysts in the epoxidation of olefins at room temperature in the presence of NaHCO3 as a promoter and H2O2 as a terminal oxidant. A comparative epoxidation study has been performed to determine the relative efficiency of the catalysts. To make the epoxidation method cost effective, a study to optimize the use of H2O2 has also been performed. To obtain evidence in favor of our suggested mechanism to this homogeneous olefin --> epoxide conversion, it was necessary to synthesize a peroxo-rich compound, namely, [MoO(O2)2BMTHA]- (7), but the attempted synthesis culminated in the isolation of [MoO(O2)2(C6H5COO)]- (8), obviously, via the hydrolysis of coordinated BMTHA.     

Evaluation of parallelism by ultrasonic echo method

The determination of parallelism in a transparent plate is usually done either by the movement of a stylus or by an optical method, such as interference fringes. For opaque objects, the only method appears to be the use of stylus. The authors have developed an acoustic method to evaluate the parallelism between faces of any block even if it is opaque to light. It is based on the echoes received from the two surfaces when incident upon by a short duration high frequency ultrasonic pulse. The paper describes the basic principle and also the methodologies for evaluation in laboratory and in industry. The method requires essentially only one side to be accessible. Theoretical and experimental results show excellent agreement up to 1° of arc. The uncertainty of measurements of results is ±0.1°. It is expected that the new method would find applications in several industries.     

多孔压电线性理论中的唯一性定理、互易定理和特征值问题

假定弹性场和电场为正定,在多孔压电线性理论中建立起唯一性定理和互易定理．在准静态电场近似下,证明多孔压电材料线性理论中的一般性定理．利用弹性场的正定性,唯一性定理得到证明．在与多孔压电体自由振动相联系的特征值问题的研究中,给出了简明的公式．文中还研究了有关算子的某些特性．以简明公式为基础,利用变分法和算子法,研究了由于小扰动产生的频移问题．还给出了特殊情况下的扰动分析．     

Resonance in Polyurea-Based Multilayer Structures Subjected to Laser-Generated Stress Waves

We report resonance associated with polyurea layers sandwiched between identical acrylic and polycarbonate plates when subjected to laser-generated stress waves of several nanoseconds in duration. Transmitted stress wave amplitudes almost 16 times the incident stress wave amplitudes are observed. An elastodynamics simulation identified the thickness of the polyurea layer as the key parameter controlling the amplitude of the transmitted stress wave. This resonance effect was found absent when the polyurea was sandwiched between the steel and aluminum plates of similar thickness. However, for these samples, a dramatic reduction in the amplitudes of the transmitted stress waves was recorded. A finite element analysis of the wave propagation through the sandwiched polyurea layer in these samples tied the large amplitude reduction to the large acoustic impedance mismatch and the viscoelastic dissipation within the polyurea layer.     

New exact solutions of Einstein—Maxwell equations for magnetostatic fields

The symmetry reduction method based on the Fréchet derivative of differential operators is applied to investigate symmetries of the Einstein-Maxwell field equations for magnetostatic fields, which is a coupled system of nonlinear partial differential equations of the second order. The technique yields invariant transformations that reduce the given system of partial differential equations to a system of nonlinear ordinary differential equations. Some of the reduced systems are further studied to obtain the exact solutions.