STRUCTURE-ACTIVITY STUDIES OF PHOTOACTIVATED ANTIVIRAL AND CYTOTOXIC TRICYCLIC THIOPHENES

The photoactivated antiviral and cytotoxic activities of the naturally occurring thiophene, alpha-terthienyl (1), and 15 synthetic analogues were evaluated against murine cytomegalovirus and Sindbis virus, and murine mastocytoma cells. After irradiation with near UV light, alpha-terthienyl and most of its analogues had significant toxicity, with minimum inhibitory concentrations in the range of 0.02-40 microM. In the absence of near UV irradiation, only one analogue had antiviral activity and five were cytotoxic. The most active analogues were those containing carboxylic acid, hydroxyl, or cyano substituents. Quantitative structure-activity relationship analysis of thiophene phototoxicity suggested that the rate of singlet oxygen production is the primary determinant of antiviral and cytotoxic activities. For phototoxicity against murine cytomegalovirus, a significant role for hydrophobicity was also demonstrated. Tricyclic thiophenes show significant potential for photochemotherapy of viral infections and cancer, and further evaluation in animal models is recommended.     

Synthesis and photochemistry of a new class of photocleavable protein cross-linking reagents

A new series of photocleavable protein cross-linking reagents based on bis(maleimide) derivatives of diaryl disulfides have been synthesised. They have been functionalised with cysteine and transient absorption spectra for the photolysis reaction have been recorded by using the pump-probe technique with a time resolution of 100 femtoseconds. Photolysis of the disulfide bond yields the corresponding thiyl radicals in less than a picosecond. There is a significant amount of geminate recombination, but some of the radicals escape the solvent cage and the quantum yield for photocleavage is 30 % in water.     

The Role of Multiple Teaching Strategies in Promoting Active Learning in Organic Chemistry

We have introduced four alternative teaching strategies into our yearlong organic chemistry course and have assessed changes in student performance relative to the same course taught by the same instructors using a more traditional lecture format. These strategies, which include reading worksheets, dialogues, in-class worksheets, and role-playing, allow the professor to move through a learning cycle that may effectively accommodate the students needs and multiple learning styles. The reading worksheets guide students through the concept phase and dialogues help students identify the importance of the concepts as they articulate these ideas for themselves. Group worksheets and role-playing provide opportunities for peer-interaction, application of knowledge, creativity, and self-expression. Others have shown that active learning strategies neither enhance nor diminish a students ability to retain factual information, a finding that is supported by our study. Our data from this one study show, however, that students taught by a more traditional approach demonstrate a greater variation in final exam performance between first and second semesters than those taught using a combination of techniques. This result reflects a shift in emphasis from the professor as an information source to the actively engaged student taking responsibility for his or her own learning. This study suggests that these methods, when used in a consistent fashion in conjunction with interactive lecturing, provide a broad base to facilitate student learning and aid in the development of higher order thinking skills.     

Discontinuous Galerkin methods on graphics processing units for nonlinear hyperbolic conservation laws

We present a novel implementation of the modal DG method for hyperbolic conservation laws in two dimensions on graphics processing units (GPUs) using NVIDIA's Compute Unified Device Architecture. Both flexible and highly accurate, DG methods accommodate parallel architectures well as their discontinuous nature produces element‐local approximations. High‐performance scientific computing suits GPUs well, as these powerful, massively parallel, cost‐effective devices have recently included support for double‐precision floating‐point numbers. Computed examples for Euler equations over unstructured triangle meshes demonstrate the effectiveness of our implementation on an NVIDIA GTX 580 device. Profiling of our method reveals performance comparable with an existing nodal DG‐GPU implementation for linear problems. Copyright © 2014 John Wiley & Sons, Ltd.     

Fusion Dynamics of Aqueous Glutamic Acid/Aminodecane/Ibuprofen Vesicles

Vesicles have been prepared at a constant molar ratio of L-glutamic acid/1-aminodecane/ibuprofen/H₂O. The fusion dynamics of the vesicles have been directly observed and followed by using optical microscopy and freeze fracture replication-electron microscopy technologies. With time increasing up to 25 minutes, the vesicles slowly fuse to form large stable vesicles. A membrane phase transition temperature is detected at 97°C.     

Two ZnII mononuclear coordination compounds with pyridinedicarboxylate and auxiliary N‐(pyridin‐4‐ylmethylidene)hydroxylamine ligands

Two new mononuclear coordination compounds, bis{4‐[(hydroxyimino)methyl]pyridinium} diaquabis(pyridine‐2,5‐dicarboxylato‐κ²N,O²)zincate(II), (C₆H₇N₂O)₂[Zn(C₇H₃NO₄)₂(H₂O)₂], (1), and (pyridine‐2,6‐dicarboxylato‐κ³O²,N,O⁶)bis[N‐(pyridin‐4‐ylmethylidene‐κN)hydroxylamine]zinc(II), [Zn(C₇H₃NO₄)(C₆H₆N₂O)₂], (2), have been synthesized and characterized by single‐crystal X‐ray diffractometry. The centrosymmetric Zn^II cation in (1) is octahedrally coordinated by two chelating pyridine‐2,5‐dicarboxylate ligands and by two water molecules in a distorted octahedral geometry. In (2), the Zn^II cation is coordinated by a tridentate pyridine‐2,6‐dicarboxylate dianion and by two N‐(pyridin‐4‐ylmethylidene)hydroxylamine molecules in a distorted C₂‐symmetric trigonal bipyramidal coordination geometry.     

The solvent effect in obtaining of acid–base multicomponent systems: thermal,structural and luminescence study

Journal of Thermal Analysis and Calorimetry - Acid–base multicomponent systems based on active pharmaceutical ingredients 2-chloro-5-nitrobenzoic acid (2Cl5NBH) and monoethanolamine were...     

Michael reaction. IV. NaNH2 catalyzed one stage reaction between phenylacetic acid dialkylamides and cinnamic acid methyl ester or dialkylamides. Influence of reaction conditions on the stereochemistry

The NaNH₂ catalyzed one stage reaction between phenylacetic acid dialkylamides and cinnamic acid methyl ester or dialkylamides was studied under various conditions. Conditions were found for easy preparation of each of the both possible diastereomeric derivatives of 2,3-diphenylglutaric acid. It was proved that catalytic amounts of NaNH₂ take part in the reaction. It is assumed that the observederythro/threo equilibrium ratios are determined by an isomerization via two different carbanions (at C₂ and C₄) of the reaction products.Part III:J. Stefanovsky andL. Viteva, Comun. Dept. Chem. Bulg. Acad. Sci.4, 159 (1971).