Mechanical and thermal properties of irradiated films based on Tilapia (Oreochromis niloticus) proteins

Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia (Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction.     

Asymmetric Catalysis on the Nanoscale: The Organocatalytic Approach to Helicenes

The first asymmetric organocatalytic synthesis of helicenes is reported. A novel SPINOL‐derived phosphoric acid, bearing extended π‐substituents, catalyzes the asymmetric synthesis of helicenes through an enantioselective Fischer indole reaction. A variety of azahelicenes and diazahelicenes could be obtained with good to excellent yields and enantioselectivities.     

The Equations of Ostwald Ripening for Dilute Systems

We consider a dilute mixture in 3D of a finite number of particles initially close to spherical, but of varying sizes, and representing one of the phases evolving according to the quasistatic dynamics. Under the scaling hypotheses that (1) typical size/typical distance and (2) deviation from sphericity/typical size are small, we associate centers and radii to each particle for the whole evolution and derive rigorously a set of ODEs fo the radii which we relate to the Lifschitz–Slyosov–Wagner theory of coarsening.     

A quantitative isoperimetric inequality for fractional perimeters

Recently Frank and Seiringer have shown an isoperimetric inequality for nonlocal perimeter functionals arising from Sobolev seminorms of fractional order. This isoperimetric inequality is improved here in a quantitative form.     

Micro and Macro Characterization of PEO-PPO-PEO Triblocks Hydrogels

Summary: Amphiphilic poly(ethylene oxide) - poly(propylene oxide) triblock copolymers are very appealing materials for biomedical application since they can be easily injected as liquid at room temperature while they produce a gel when in the body. On the other hand, these materials no longer hold the gel state when in presence of solvent (as physiological solutions) due to the dilution of the system. To overcome these limitations Cohn and coworkers 1 have synthesized a novel thermo-responsive systems by extending the chain of the commercially available PEO-PPO copolymer named F127. The aim of this study was to evaluate the effect of the chemical modification on the macroscopic, rheological, and microscopic, transport, properties of these new materials.     

Rearrangements of 2,6-disubstituted arylhydrazides

It is shown that the rearrangement of phenylacetic acid hydrazides obtained from 8-substituted N-amino-1,2,3,4-tetrahydroquinolines under the influence of PCl₅ proceeds through a step involving the formation of a cyclohexadienoneimine derivative (which was isolated and characterized), which is formed by attack on the 10 position of the tetrahydroquinoline ring. A subsequent 1,3-sigmatropic shift of the cyanobenzyl group leads to nitriles of [6-(8-R-1,2,3,4-tetrahydroquinolyl)]phenylacetic acids. The possibility of their formation through another cyclohexadienoneimine intermediate (formed as a result of attack at the 8 position) is assumed. The nature and pathways for the formation of the side products in the rearrangement were ascertained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 504–507, April, 1978.     

Some remarks about surface effects in magnetic superconductors

A new choice for the boson transformation function is employed for the study of the electromagnetic-field distributions at the interface of vacuum with a magnetic superconductor. The relation with previous approaches is discussed.