The self-assembly of two new types of stable hydrogen-bonded supramolecular aggregates-bisrosettes-that are based on parallel, connected CA3.M3 rosettes is reported. The minimization of intermolecular steric hindrance-peripheral crowding within the aggregate-is proposed as the structural feature responsible for selecting the cyclic CA3'M3 rosette over competing linear hydrogen-bonded networks a...

Celluloid in museum collections is very unstable; therefore, heritage professionals carry out research studies dedicated to understanding its decay and prolonging lifetime. This paper addresses the need compare select suitable analytical methods for that purpose. Thermogravimetric analysis coupled with Fourier transform infrared spectroscopy, evolved gas analysis–mass spectrometry, double shot ...

Mutations affecting specific starch biosynthetic enzymes commonly have pleiotropic effects on other enzymes in the same metabolic pathway. Such genetic evidence indicates functional relationships between components of the starch biosynthetic system, including starch synthases (SSs), starch branching enzymes (BEs), and starch debranching enzymes; however, the molecular explanation for these func...

Phenylalanine hydroxylase, the enzyme that catalyzes the irreversible hydroxylation of phenylalanine to tyrosine, was purified from rat kidney with the use of phenyl-Sepharose, DEAE-Sephacel, and gel permeation high pressure liquid chromatography. Our most highly purified fractions had a specific activity in the presence of 6-methyltetrahydropterin, of 1.5 mumol of tyrosine formed/min/mg of pro...

Purpose: To develop a safe mucoadhesive gel for nasal drug delivery using okra polysaccharide. Methods: Rizatriptan benzoate nasal gel was developed using natural polysaccharide obtained from the Abelmoschus esculentus. The gel formulation was characterized for pH, viscosity, mucoadhesion, and in vitro permeation. Permeation parameters obtained include drug flux (j), permeation coefficient (kP)...

Red seaweeds are known sources of polysaccharides, some of which possess antiadhesive properties by inhibition of P-selectin-mediated leukocyte rolling. We here report the chemical composition and the antiadhesive activity of polysaccharide-rich fractions from the red alga Lithothamnion muelleri (Hapalidiaceae). The crude fractions enriched in polysaccharides B1 and B2 were obtained, respective...

Arthrobacter sp. strain NO-18 was first isolated from soil as a bacterium which could degrade the sodium acrylate oligomer and utilize it as the sole source of carbon. When 0.2% (wt/wt) oligomer was added to the culture medium, the acrylate oligomer was found to be degraded by 70 to 80% in 2 weeks, using gel permeation chromatography. To determine the maximum molecular weight for biodegradation...

In here, the nonisothermal decomposition kinetics of co-polymers based phenothiazine was present-ed. For this, firstly, 3, 7-di-2-thienyl-10H-phenothiazine (TF) prepared via an optimized Suzu-ki–Miyaura cross-coupling reaction. After monomer characterization, copolymerization re-actions with EDOT and thiophene were performed by electrochemical technique. The molecular masses found gel permeatio...

The synthesis of poly(L-glutamic acid) (PG) was investigated. Reduction poly(benzyl-L-glutamate) by the palladium/charcoal catalyst proved to be an effective method for obtaining polyglutamic acid pure and particularly exhibiting in α-helix secondary structure. structure this synthetic polypeptide assessed infrared spectroscopy, gel permeation chromatography, proton nuclear magnetic resonance t...

Embrittlement caused by injection molding was investigated on a commercial grade of Polybutylene terephthalate (PBT). The effect temperature and residence time in the barrel mechanical properties studied. Results were discussed from macromolecular analysis Gel Permeation Chromatography crystallinity measurements differential scanning calorimetry. It shown that embrittlement exclusively occurs c...