Metal contact effect on the persistent internal polarization in pure and doped polystyrene

Photo-electrets of pure and copperphthalocyanine doped polystrrene films (thickness 20 μm) were formed by UV- radiation in an electric field with Al, Cu, Ni, Zn, Cd and Pb as electrode materials. The depolarization current and the released charge show a strong dependence on the material of the electrode. Two distinct regions in the current decay characteristic indicate that the polarization consists of trapped holes and electrons. The amount of charge injected increases with decreasing work function of the contact metal. Doping increases the stability of the charge.     

Massless particles and cosmology

Post recombination density perturbations have been studied in a two-component matter-radiation universe. The study has been carried out for variable matter and radiation densities. The possibility of the existence of different kinds of neutrinos in addition to the electronic, muonic and taonic has been considered and conclusions have been drawn as to the upper limit of the radiation density for different values of Ω _m .     

Copper(II) and cobalt(II) salts of d-, I- and dl-mandelic acids: Their infrared,electronic reflectance spectra,DTA and TGA

The copper(II) and cobalt(II) salts of d-, l- and dl-forms of mandelic acids were prepared in the solid form. These were found to have a general formula M(C₆H₅CHOHCOO)₂. Infrared (4000–200 cm^?1), electronic reflectance spectra and DTA and TGA of these six compounds were investigated. This data is discussed and the likely structural differences between the d- (or l-) form and the dl-form are suggested.     

Facile one pot multicomponent synthesis of novel 4-(benzofuran-2-yl)-2-(3-(aryl/heteryl)-5-(aryl/heteryl)-4,5-dihydro-1H-pyrazol-1yl)thiazole derivatives

An efficient base catalyzed one pot multicomponent reaction of aryl/hetryl chalcones, thiosemicarbazide and 1-(benzofuran-2-yl)-2-bromoethan-1-one was developed to synthesize the novel 4-(benzofuran-2-yl)-2-(3-(aryl/heteryl)-5-(aryl/heteryl)-4,5-dihydro-1H-pyrazol-1yl)thiazole derivatives.     

Synthesis of supramolecular precision polymers: Crystallization under conformational constraints

Placing artificial folding elements into precision polymers is an important strategy to systematically study structure formation in self‐assembly, particularly in the semicrystalline state. To this purpose, a series of precision polymers bearing either a N‐ protected or N‐ unprotected diaminopyridine (DAP) unit after every 16th, 18th, and 20th carbon as well as a urea unit after every 20th carbon along a polyethylene‐like polymer were synthesized via acyclic diene metathesis polymerization and subsequent hydrogenation. The polymers thus contain either H‐bonds (urea/DAP), π–π‐elements (DAP), or no H‐bonds (respective N? protected urea/DAP‐units) in their main chain, able to consequently study the crystallization behavior under influence of such supramolecular moieties. Therefore, the thermal properties and crystallization behavior were analyzed via differential scanning calorimetry (DSC) as well as wide angle X‐ray diffraction. The obtained crystalline polymer is influenced by the different supramolecular interactions existing between adjacent polymer chains and the varying defect size exerted by the incorporated functional groups. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3736–3748     

Facile Syntheses of Novel Salts of a Triazole Antifungal Agent with Enhanced Solubility

Acid addition salts of a triazole antifungal agent itraconazole were prepared with an aim to enhance the aqueous solubility and dissolution characteristics of the drug. Nitric, sulfuric, and p‐toluenesulfonic acid addition salts ( 1a , 1b , 1c ) were prepared using facile synthetic procedures. The solubility of the salts in water was found to be 24, 22, and 58 mg/mL, respectively, for 1a , 1b , and 1c , which is significantly higher than that of itraconazole (1 ng/mL). In addition to this, solubility of the salts in simulated gastric fluid (SGF) and other pharmaceutically used solvents such as ethanol and propylene glycol was also improved to a great extent. Also, it was observed that from 1a , 1b , and 1c , approximately 33, 26, and 45% drug was released in SGF in 3 h, whereas less than 10% drug was released from the free base form.     

Synthesis and characterization of oxygen depleted tert-amine calix[4]arene ligands and study the effect on sigma non-opioid intracellular protein receptor

Structural Chemistry - This study focuses on the biological prospects of oxygen-depleted calix[4]arene ligands on a protein target. Because of their extensive medical relevance, the oxygen-depleted...     

Reaction on Water: A Greener Approach for the Thia Michael Addition on N-Aryl Maleimides

A greener, economical, and efficient methodology for the Michael addition of thiols to N-aryl maleimides has been developed.     

Highly sensitive detection of platelet-derived growth factor on a functionalized diamond surface using aptamer sandwich design

Aptamer-based fluorescence detection of platelet-derived growth factor (PDGF) on a functionalized diamond surface was demonstrated. In this work, a sandwich design based on the ability of PDGF to bind with aptamers at its two available binding sites was employed. It was found that this sandwich design approach significantly increases the fluorescence signal intensity, and thereby a very low detection limit of 4 pM was achieved. The effect of the ionic strength of MgCl(2) buffer solution was also investigated, and the most favourable binding for PDGF-BB occurred at a Mg(2+) concentration of 5.5 mM. Since the aptamers bind to the target PDGF with high affinity, fluorescence detection exhibited high selectivity towards different biomolecules. The high reproducibility of detection was confirmed by performing three cycles of measurements over a period of three days.