Enantioseparation of nicotine alkaloids in cigarettes by CE using sulfated β‐CD as a chiral selector and a capillary coated with amino groups

Nicotine (NC) and its related compounds (cotinine (CN), nornicotine (NN), anatabine (AT) and anabasine (AB)) were simultaneously enantioseparated by CE using a capillary with amino groups and sulfated β‐CD as a chiral selector. The optimum running conditions were found to be 30 mM acetate buffer (pH 5.0) containing 8% sulfated β‐CD with an applied voltage of +15 kV at 30°C using direct detection at 260 nm. Using a capillary coated with amino groups, the EOF migrates toward the positive pole. However, when sulfated β‐CD was added to the BGE, it was found that the EOF migrated toward the negative pole due to ionic adsorption of sulfated β‐CD to amino groups on the capillary inner wall. All the cationic analytes migrated as anions, suggesting that they formed stable anionic complexes with sulfated β‐CD. With this system and a simple pretreatment with mini‐cartridges, NC alkaloids in five cigarette samples were enantioseparated. As a result, each of the compounds except for CN was detected. In the case of NC, only (S)‐NC was detected (more than 99.9%), but in the case of NN, AT and AB, the ratios of (S)‐isomer to total isomers were in the ranges 58–70, 81–85 and 59–65%, respectively. On the other hand, only NC was detected in cigarette smoke and the ratio of (S)‐ and (R)‐NCs was 96:4. The amounts of NC alkaloids in cigarettes suggest that the production of (R)‐NC resulted from racemization due to the high temperature/burning of the cigarette.     

Effect of controlling optical wavelength by spectacle lenses on visual quality

Optical Review - In this study, the effects of selectively yellow-cut lenses on contrast sensitivity were investigated in healthy young and middle-aged individuals and elderly patients with...     

Isolation of chemical constituents from Enicosanthum cupulare (King) Airy-Shaw

Six chemical constituents were isolated from Enicosanthum cupulare (King) Airy-Shaw. The structures of the isolated compounds were determined using 1D, 2D-NMR and were found to be identical to those previously reported for these compounds. Three aporphine alkaloids, O-methylmoschatoline, liriodenine and oxostephanine were isolated from this plant for the first time. In addition, we examined the effects of these compounds on melanogenesis in murine B16 melanoma cells; O-methylmoschatoline increased melanin content in these cells.     

One-pot synthesis of optically active allyl esters via lipase-vanadium combo catalysis

The combination of vanadium-oxo compounds (3 or 4) with a lipase produced the regio- and enantioconvergent transformation of racemic allyl alcohols (1 or 2) into optically active allyl esters. In this system, the vanadium compounds catalyzed the continuous racemization of the alcohols along with the transposition of the hydroxyl group, while the lipase effected the chemo- and enantioselective esterification to achieve the dynamic kinetic resolution.     

Kaempferol glycosides in the flowers of carnation and their contribution to the creamy white flower color

Three flavonol glycosides were isolated from the flowers of carnation cultivars 'White Wink' and 'Honey Moon'. They were identified from their UV, MS, 1H and 13C NMR spectra as kaempferol 3-O-neohesperidoside, kaempferol 3-O-sophoroside and kaempferol 3-O-glucosyl-(1 --> 2)-[rhamnosyl-(1 --> 6)-glucoside]. Referring to previous reports, flavonols occurring in carnation flowers are characterized as kaempferol 3-O-glucosides with additional sugars binding at the 2 and/or 6-positions of the glucose. The kaempferol glycoside contents of a nearly pure white flower and some creamy white flower lines were compared. Although the major glycoside was different in each line, the total kaempferol contents of the creamy white lines were from 5.9 to 20.9 times higher than the pure white line. Thus, in carnations, kaempferol glycosides surely contribute to the creamy tone of white flowers.     

Evolution of the Kondo effect in a quantum dot probed by shot noise

We measure the current and shot noise in a quantum dot in the Kondo regime to address the nonequilibrium properties of the Kondo effect. By systematically tuning the temperature and gate voltages to define the level positions in the quantum dot, we observe an enhancement of the shot noise as temperature decreases below the Kondo temperature, which indicates that the two-particle scattering process grows as the Kondo state evolves. Below the Kondo temperature, the Fano factor defined at finite temperature is found to exceed the expected value of unity from the noninteracting model, reaching 1.8±0.2.     

A study on the role of gelatin in methacrylic-acid-based gel dosimeters

In radiotherapy treatment, polymer gel dosimetry can be used for verifying three-dimensional (3D) dose distributions. Gelatin is generally used as a gelling agent in the dosimeters. In this paper, another role of gelatin in a methacrylic-acid-based gel dosimeter (MAGAT) is investigated. Temperature increases due to exothermic polymerization in the irradiated gel are measured directly. Dose–R₂ responses are also obtained using MRI. It is shown that no appreciable increases in either temperature or R₂ are observed in MAGAT dosimeters made without gelatin, and that significant temperature and R₂ increases are observed when very low gelatin concentrations are used. These results indicate that gelatin is an important enabler for radiation-induced free-radical polymerization in methacrylic-acid-based gels. When gelatin is replaced by amino acids, changes in temperature are observed, along with small changes in R₂. The resulting dosimeter solutions remain transparent because the polymer does not precipitate as it does in regular MAGAT dosimeters containing gelatin. When the amino acids are replaced by acids without amino groups, no temperature or R₂ changes are observed, indicating that no polymer forms. These results show that amino groups (and possibly other functional groups) on the gelatin catalyze the radiation-induced free-radical polymerization that occurs in MAGAT dosimeters.     

The effect of UV irradiation on the reduction of Au(III) ions adsorbed on manganese dioxide.

The effect of UV (ultraviolet) irradiation on the adsorption of Au(III) ions on manganese dioxide and their reduction to Au(0) (gold with 0 valence state) was investigated using XPS (X-ray photoelectron spectroscopy) and 197Au M?ssbauer spectroscopy. The UV irradiation accelerated the adsorption and the reduction. From the fact that the proportion of Au(0) estimated from Au 4f XPS spectra for surface analysis was significantly smaller than that from 197Au M?ssbauer spectra for bulk analysis, we deduced that Au(0) was interpenetrated to the inside of manganese dioxide (into deeper places than about 30 A) where XPS is impossible to detect. The content of surface hydroxyl groups on manganese dioxide also increased due to the UV irradiation. The relationship between the charge in the content of hydroxyl groups and the interpenetration of Au(0) is discussed.