Separation and determination of some stereoisomers by capillary gel electrophoresis with cyclodextrin incorporated in polyacrylamide gel

Capillary gel electrophoresis (CGE) was successfully applied to the separation of optically active isomers and position isomers by incorporating a suitable cyclodextrin chiral selector in polyacrylamide gel. A commercially available ß-cyclodextrin (ß-CD) was used for enantioselectivity towards o-, m- and p-nitrobenzoic acid, o-, m- and p-hydroxybenzoic acid, o-, m- and p-toluic acid and the optical isomers of dansyl-D,L-leucine and R,S-1,1-binaphthyl-2,2-dihydrogenphosphate. Especially the effect of organic solvents, such as acetonitrile, methanol, dimethylsulphoxide and others were examined in detail. The resolution varied to some extent with the addition of the organic solvent to the polyacrylamide gel and the running buffer solution. The possible mechanism has also been discussed. In addition, quantitative aspects of the separation of stereoisomers using CGE have been studied, showing that both the resolution and accuracy of the determinations were affected by the ratio of the enantiomers.     

Vinyl Polymerization. 439. Vinyl Polymerization Initiated by Poly(Ethylene Glycol] Diglycolic Acid or its Sodium Salt

Abstract

The polymerization of some kinds of vinyl monomer was found to occur in aqueous solutions of poly(ethylene glycol) diglycolic acid (PEG Acid) or sodium poly(ethylene glycol) diglycolate (PEG Acid Na) through radical mechanisms without any further initiator, as a so-called “uncatalyzed polymerization.” Although the initiating radical species for PEG Acid was determined to be the same as that for PEG Acid Na by means of the spin-trapping technique, the initiating ability of PEG Acid was higher than that of PEG Acid Na. These results are assumed to be attributable to the difference in the initiation mechanisms of the two systems and in the incorporating abilities of monomer into the hydrophobic areas formed by PEG Acid and PEG Acid Na.     

Analytical investigations of the behavior of silole-core dendrimers with peripheral globotriaose in water and acetone/water mixed solvent

A new compound having a 2,3,4,5-tetraphenylsilole derivative on the center silicon of Dumbbell(1)6Gb3; Silole-Dumbbell(1)6Gb3 (1) was previously reported. It was found that 1 exhibited strongly increased fluorescence both in water and in a 96% acetone/water mixed solvent. The physical behavior of 1 in water and in the 96% acetone/water mixed solvent was investigated, and analyses including fluorescence quantum yields, dynamic-light-scattering (DLS), atomic-force-microscopy (AFM), and fluorescence microscopy were carried out. It was clarified that 1 dynamically formed different types of aggregates in water and in higher acetone concentrations to yield high aggregation-induced emission (AIE) effects due to the formation of micelle-like particles in water and inversion-type micelles in the acetone/water mixed solvent, respectively.     

A new biisoflavonoid from the roots of Erythrina variegata

A new biisoflavonoid, biseryvarin A (1a), together with two known compounds were isolated from the roots of Erythrina variegata. The structure of biseryvarin A was established on the basis of spectroscopic evidence. Biseryvarin A is the first dimeric isoflavonoid possessing isoprenoid groups from the genus Erythrina. Biseryvarin A showed low activity against methicillin-resistant Staphylococcus aureus (MRSA).     

Specifications of a neutron exposure accelerator system for biological effects experiments (NASBEE) in NIRS

We developed a neutron irradiation facility, neutron exposure accelerator system for biological effect experiments (NASBEE) for biological studies in National Institute of Radiological Sciences, Japan. Irradiation field of 2 MeV average neutrons generated by a Be(d–n)B reaction is established. Dose uniformity of 240 mm in diameter irradiation field is producible within ±2.5% with a dose rate of 0.87 Gy/h at sample target distance of 1170 mm. Two irradiation rooms, a specific pathogen-free (SPF) conditioned one and a conventional, are now available. Irradiation protocols for in vitro experiments are now established and demonstrated by obtaining a relative biological effectiveness (RBE) of cell inactivation measured to be 3.54 with 10% survival dose (D₁₀).     

Pressure-induced reentrant micellization of amphiphilic block copolymers in dilute aqueous solutions

The pressure-induced structural changes of a block copolymer, poly(2-ethoxyethoxyethyl vinyl ether)-block-poly(2-hydroxyethyl vinyl ether) (pEOEOVE-b-pHOVE) in aqueous solutions, were studied by means of small-angle neutron scattering (SANS) and dynamic light scattering (DLS) from atmospheric pressure up to 400 MPa. pEOEOVE-b-pHOVE formed a spherical micellar structure above 40 degrees C due to poor solubility of pEOEOVE. Micellization phase diagram was determined by DLS, and a covex-upward pressure-temperature (P-T) phase diagram was obtained having a peak around (P,T)=(150 MPa,48 degrees C). The SANS curves at 50 degrees C were analyzed as a function of P. The micellar core size decreased by pressurizing at low P's (P相似文献   

Aqueous self-aggregates of amphiphilic zinc 3-hydroxy- and 3-methoxy-chlorins for supramolecular light-harvesting systems

Aqueous aggregates of zinc 3¹-hydroxy- and 3¹-methoxy-13¹-oxo-chlorins possessing a hydrophilic tetraoxyethylene chain were prepared. Zinc 3¹-methoxy-chlorin formed a well-ordered aggregate without intermolecular hydrogen bonding which has been widely accepted in most structural models for BChl-c, d, e aggregates in a major light-harvesting antenna of green photosynthetic bacteria, chlorosome.