General Formation of Macro-/Mesoporous Nanoshells from Interfacial Assembly of Irregular Mesostructured Nanounits

Mesoporous core–shell nanostructures with controllable ultra-large open channels in their nanoshells are of great interest. However, soft template-directed cooperative assembly to mesoporous nanoshells with highly accessible pores larger than 30 nm, or even above 50 nm into macroporous range, remains a significant challenge. Herein we report a general approach for precisely tailored coating of hierarchically macro-/mesoporous polymer and carbon shells, possessing highly accessible radial channels with extremely wide pore size distribution from ca. 10 nm to ca. 200 nm, on diverse functional materials. This strategy creates opportunities to tailor the interfacial assembly of irregular mesostructured nanounits on core materials and generate various core–shell nanomaterials with controllable pore architectures. The obtained Fe,N-doped macro-/mesoporous carbon nanoshells show enhanced electrochemical performance for the oxygen reduction reaction in alkaline condition.     

Intake of different chemical species of dietary arsenic by the japanese,and their blood and urinary arsenic levels

We calculated the intake of each chemical species of dietary arsenic by typical Japanese, and determined urinary and blood levels of each chemical species of arsenic. The mean total arsenic intake by 35 volunteers was 195±235 (15.8-1039) μg As day^?1, composed of 76% trimethylated arsenic (TMA), 17.3% inorganic arsenic (As_i), 5.8% dimethylated arsenic (DMA), and 0.8% monomethylated arsenic (MA): the intake of TMA was the largest of all the measured species. Intake of As_i characteristically and invariably occurred in each meal. Of the intake of As_i, 45-75% was methylated in vivo to form MA and DMA, and excreted in these forms into urine. The mean measured urinary total arsenic level in 56 healthy volunteers was 129±92.0 μg As dm^?3, composed of 64.6% TMA, 26.7% DMA, 6.7% As_i and 2.2% MA. The mean blood total arsenic level in the 56 volunteers was 0.73±0.57 μg dl^?1, composed of 73% TMA, 14% DMA and 9.6% As_i. The urinary TMA levels proved to be significantly correlated with the whole-blood TMA levels (r = 0.376; P<0.01).     

A precision measurement of the hyperfine structure of87Sr+

The ground state hyperfine splitting of⁸⁷Sr⁺ was measured with a precision of 1×10^–8. The experiments were performed with an RF ion trap connected to an ISOL (isotope separator on-line), where all the possible transitions between Zeeman sublevels were observed by a laser-microwave double resonance method. The magnetic dipole hyperfine constant was determined to beA=–1 000 473.673 (11) kHz.     

Fluorescent humic substances–arsenic complex in well water in areas where blackfoot disease is endemic in Taiwan

The relationship between the four components, (1) fluorescence intensity, (2) arsenic concentration, (3) pH and (4) total dissolved solids, (TDS) measured in well waters from areas in Taiwan where blackfoot disease (BFD) is endemic was studied, as well as the relationships between the four degrees of BFD and each of the above four symptomatic components, in order to evaluate the etiological factors of BFD more progressively. The following 95% confidence intervals were obtained in well water samples (n = 1189): fluorescence intensity, 26.837–32.570; arsenic concentration, 0.103–0.127 mg dm^?3; pH, 7.466–7.519; and TDS 733.063–801.647 mg dm^?3. Fluorescence intensities of the four degrees of BFD were not all the same (F = 64.54, P < 0.001), and nor were arsenic concentrations (F = 72.03, P < 0.001), pH values (F = 7.30, P < 0.001), nor TDS values (F = 10.76, P < 0.001). In addition, multiple comparisons indicate that the higher the epidemical degree, the higher the fluorescence intensities, arsenic concentrations and pH values become; however, such a relationship is not found for TDS values. Moreover, the fluorescence intensities have positive linear correlations with arsenic concentrations (r = 0.49, P < 0.001), pH (r = 0.25, P < 0.001), and TDS (r = 0.18, P < 0.001), as do the arsenic concentrations with pH (r = 0.22, P < 0.001). Of the four epidemical degree groups, pairs are not significantly different from one another in correlation coefficients between fluorescence intensity and arsenic concentration, which implies a steady relationship between fluorescent compounds and arsenic. We conclude that fluorescent compounds in well water, as possible etiological factors of BFD, are closely related to arsenic along with pH and TDS values in the areas where BFD is endemic. In addition, we infer that a complex is formed by fluorescent compounds, arsenic and other metals.     

Spin structure and weak ferromagnetism of Mn3Sn

The compound Mn₃Sn shows an interesting magnetic behavior. A triangular screw spin structure has been observed below 250 K, whose period is independent of temperature. The screw structure is sensitive to heat treatment, alloy composition and impurity content.     

Important role of the 3-mercaptopropionamide moiety in glutathione: promoting effect on decomposition of the adduct of glutathione with the oxoammonium ion of TEMPO

Cyclic voltammetry of TEMPO in aqueous 0.1 M NaOH in the presence of glutathione (GSH) or cysteine (Cys) indicated the following points: (i) Both of the thiols rapidly formed adducts 3 with oxoammonium ion 1 anodically generated from TEMPO. (ii) 3 generated from GSH entered a succeeding reaction that generated N-oxide anion 2- (the reduced TEMPO). (iii) 3 produced from Cys remained intact over the time scale of voltammetry. A structural feature of GSH was considered to contribute to the observed behavior of this tripeptide. Possible structural features were evaluated by screening various thiols on the basis of whether they provided GSH-like voltammetric results. The 3-mercaptopropionamide group with an amide hydrogen in GSH was determined to be responsible for the observed difference between GSH and Cys. The likely function is to transform 3 from GSH into a 5-imino-1,2-oxathiolane intermediate, thereby releasing 2-. Product analysis for reactions of model thiols representing GSH and Cys with 1 provided support for this argument and suggested that the reaction of GSH or Cys with 1 would produce the corresponding disulfides, regardless of whether a five-membered ring intermediate was formed. The proposed function of the 3-mercaptopropionamide moiety of GSH may provide useful insight for the molecular design of exogenous thiol compounds as novel drugs for the treatment of GSH-depletion-related disorders.     

Studies on the antitumor-promoting activity of naturally occurring substances. II. Inhibition of tumor-promoter-enhanced phospholipid metabolism by umbelliferous materials

Ninety-five extracts prepared from 14 kinds of Umbelliferous materials were studied to determine their effects on tumor-promoter-induced phenomena in vitro. Of the materials, 5 Chinese crude drugs, two Bai-Hua Qian-Hu classified as Q-I and Q-II types, the root of Peucedanum praeruptorum Dunn., Zi-Hua Qian-Hu, the root of P. decursivum Maxim., Tang-Bai-Zhi, the root of Angelica dahurica Benth, et Hook. var. pai-chi Kimura, Hata et Yen., Dang-Gui, the root of A. acutiloba Kitagawa and 2 Umbelliferous plants, ashita-ba. A. keiskei Koidz., and ama-nyuu, A. edulis Miyabe, showed potent inhibitory effects on 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated 32Pi incorporation into phospholipids of cultured cells. From the active fraction of the crude drug "Tang-Bai-Zhi," imperation (1), isoimperatoin (2), oxypeucedanin (3), pabulenol (4), neobyakangelicol (5) and byakangelicin (6) were identified as active or inactive principles. Compound 4 had not previously been isolated from Tang-Bai-Zhi, A. dahurica var. pai-chi. We also discuss the structure-activity relationship among the above 6 kinds of linear-type furanocoumarins, together with 3 kinds of antitumor-promoter coumarins having the same skeleton, psoralen (7), bergapten (8) and xanthotoxin (9), obtained from "ashita-ba" (eaten as a vegetable in Japan). Among the compounds in the present experiment, compounds 1 and 2 showed potent inhibitory activity at the concentration of 50 micrograms/ml and 3-9 were found to have less or no activity.     

Diastereoselective addition of organolithiums to 1,3-oxazolidines complexed with aluminum tris(2,6-diphenylphenoxide) (ATPH)

1,3-Oxazolidines were easily obtained by condensation of N-substituted (R)-phenylglycinol with aldehydes. Addition of organolithium reagents to 1,3-oxazolidines by complexation with the bulky Lewis acid aluminum tris(2,6-diphenylphenoxide) (ATPH) readily produced the corresponding chiral amines with good yield and high diastereoselectivity. The configuration of the new stereogenic center was shown to be opposite to that of adducts obtained for the same 1,3-oxazolidines using Grignard reagents. The best diastereoselectivity was achieved using N-isopropyl-1,3-oxazolidines. The mechanism of addition was deduced by determining the stereochemistry of the iminium-aluminum complex by NOE experiments.