Alumina‐Incorporated Polyesteramide from Non‐Edible Seed Oils

To improve the physico‐mechanical and chemical resistance properties, lower the curing temperature of annona squamosa and pongamia glabra seeds oils based polyesteramides [ASPEA, PGPEA], as well as to convert the non‐edible seed oils into value added products, their respective alumina‐incorporated polyesteramides resins [Al‐ASPEA, Al‐PGPEA] have been synthesized. The resins and their coatings have been tested for their chemical, physico mechanical and chemical/corrosion resistance properties. These properties were compared among the prepared resins and with that of previously reported alumina filled linseed polyesteramide [Al‐LPEA]. It was observed that Al‐PGPEA‐71, which has the highest amount of oleic acid chains, shows the best physico‐mechanical and chemical resistance properties.     

THE CHEMICAL MODIFICATION OF POLYVINYL CHLORIDE

Abstract

Poly (vinyl chloride) (PVC) is commercially one of the most important thermoplastics in the world today. Its growth rate averaged 7% per annum in the 1970s. In 1980 it was the second largest volume thermoplastic used in the United States (the first being low-density polyethylene (LDPE) and was the lowest priced among the five leading plastics: LDPE, PVC, high-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS).     

Structure and Stability of Polyvinyl Chloride

Abstract

Polyvinyl chloride (PVC) was first prepared in the laboratory over a hundred years ago. Due to its inherent instability the commercial applications of the polymer could only be developed after the development of effective means for its stabilization. PVC started to gain commercial significance in the late thirties and since then has continued to gain in importance. By using modifying agents (plasticizers, fillers, stabilizers, and other additives), it can be modified to exhibit an extremely wide range of properties.     

Design calculations of an accelerator based BSA for BNCT of brain cancer

Monte Carlo simulations were carried out to calculate optimum design parameters of an accelerator based Beam Shaping Assembly (BSA) for Boron Neutron Capture Therapy (BNCT) of Brain Cancer setup. Epithermal beam of neutrons were obtained through moderation fast neutrons from ⁷Li(p,n) reaction in a high density polyethylene moderator and a graphite reflector. The dimensions of the moderator and the reflector were optimized through optimization of epithermal/fast neutron intensity ratio as a function of geometric parameters of the setup. Results of our calculation showed the capability of our setup to treat the tumor within 4 cm of the head surface. The calculated Peak Therapeutic Ratio for the setup was found to be 2.15. With further improvement in the polyethylene moderator design and brain phantom irradiation-arrangement, the setup capabilities can be improved to reach further deep-seated tumor.     

Mixed micelles of amphiphilic drug promethazine hydrochloride and surfactants (conventional and gemini) at 293.15K to 308.15K: Composition, interaction and stability of the aggregates

Micellization of an amphiphilic phenothiazine drug promethazine hydrochloride (PMT) in presence of conventional (CTAB and TTAB) as well as gemini (16-s-16 and 14-s-14, s=4-6) cationic surfactants has been studied conductometrically at different temperatures. Critical micelle concentration values (cmc and cmc(id)) indicate mixed micelle formation among the two components. Micellar mole fractions of surfactants (X(1), X(1)(M) and X(1)(id)) show greater contribution of surfactants. Interaction parameter, β, suggests attractive interactions in the mixed systems. The thermodynamic parameters suggest dehydration of hydrophobic part of the drug at higher temperatures.     

Comparison of the photochemical behaviors of α-tocopherol and its acetate in organic and aqueous micellar solutions

Photoionization is known to take place when α-tocopherol (TOH) is excited to the S(1) state in a polar medium. It has been previously suggested that TO(?) is formed only as a result of proton release by TOH(?+), a process that is expected to occur, in a protic solvent, on the subnanosecond time scale. Recent redeterminations of the molar absorption coefficients of e(aq)(–) (Hare J. Phys. Chem. A 2010, 114, 1766) and of TOH(?+) and TO(?) (Naqvi J. Phys. Chem. A 2010, 114, 10795) have paved the way for testing the above suggestion, even if subnanosecond time resolution is not available, since it implies the equality of [e(aq)(–)](0) and [TO(?)](0), where [···](0) denotes the concentration of the enclosed species immediately after a nanosecond laser pulse. Nanosecond pump-probe spectroscopy of TOH in aqueous micellar solution (AMS) and two organic solvents with similar polarities (acetonitrile and methanol) has revealed that prompt formation of TO(?) through dissociation (TOH + hν → TO(?) + H(?)) is not negligible even in AMS. In acetonitrile, TOH(?+) and TO(?) are formed with comparable yields, and the former converts quantitatively into TO(?) within 15 μs. In methanol, TO(?) was observed, but no evidence was found for electron ejection from TOH. Only one photoproduct, namely TO(?), could be detected when α-tocopherol acetate (TOAc) was excited to the S(1) state in several polar and nonpolar solvents; TOAc has been found to be a more efficient energy degrader than TOH.     

In Situ Measurement of Excitation Intensity for Fluorescence Excitation Spectroscopy

It is argued that the double-beam method for the automatic correction of fluorescence excitation spectra, which proved to be a great boon in the days of analog instrumentation, has become, after the advent of digital techniques for acquiring and manipulating spectral data, more of a hindrance than a help; the benefits of reverting to a single beam device and making in situ measurement of the excitation intensity are pointed out.     

Focusing of an electromagnetic plane wave into a uniaxial crystal by a Wood lens

High frequency fields, refracted by a geometry containing a Wood lens placed at a certain distance from a planar uniaxial interface, are derived by using Maslov’s method. The geometrical optics approximation generally valid for high frequency fields fails in the vicinity of a caustic. Maslov’s method is a systematic procedure for predicting the field in the caustic region, combining the simplicity of the ray and the generality of the transform method. Numerical computations are made for the field pattern around the caustic by using Maslov’s method. The results are found to be in good agreement with those obtained using Kirchhoff’s approximation.      

Synthesis of Novel Symmetric Porphyrin Schiff Base Dimers by Solid–Liquid Reaction Methodology

A new convenient solid–liquid condensation reaction procedure for the synthesis of novel asymmetric and symmetric meso‐tetraarylporphyrin and metalloporphyrin Schiff bases is reported. The condensation reaction between β‐formyl porphyrin or metalloporphyrins and aromatic amines was carried out at solid–liquid interface by using neutral alumina powder as a solid support for β‐formyl porphyrin or metalloporphyrins and absolute ethanol as the carrier solvent for aromatic amines. Six different asymmetric porphyrin/metalloporphyrin Schiff bases were synthesized via solid–liquid interface reaction methodology. The same solid–liquid synthetic methodology was applied for the synthesis of six novel symmetric Schiff base porphyrin/metalloporphyrin dimers. The comparison of UV–visible spectra of porphyrin Schiff base monomers and dimers revealed that some degree of electronic perturbation has occurred upon dimerization as the Soret bands of the monomers underwent peak broadening along with red shifts. Column chromatography and crystallization were used to purify the compounds. Fourier transform infrared, UV–visible, elemental analysis, ¹H NMR, and mass spectrometry were used to characterize the newly synthesized compounds.