Hypoxic condition-selective upconversion via triplet–triplet annihilation based on POSS-core dendrimer complexes

The influence on the efficiencies of the triplet–triplet annihilation (TTA)-supported upconversion by oxygen under biomimetic conditions was investigated. From the solution containing the dendrimer complexes based on polyhedral oligomeric silsesquioxane (POSS)-core dendrimer with the Pt complex of octaethylporphyrin (PtOEP) and anthracene in PBS, the fluorescence emission of anthracene depending on the dissolved oxygen (DO) concentrations via the TTA-supported upconversion was obtained with the excitation light at 540 nm. In particular, we observed strong emission only under hypoxic conditions. In addition, it was found that the emission intensity via TTA-supported upconversion can be reversibly regulated by the DO concentrations in the solution.     

Effect of interrupted eruption on the enamel organ of the rat incisor

The aim of this study was to investigate the behavior of rat incisor tissues during the inhibition of tooth eruption. Twenty Sprague-Dawley rats were used in this study, and incisor eruption was inhibited by a screw pin. Animals were sacrificed 1, 3, 7 and 14 days after the start of the experiment. Cross-sections at the mesial point of the mandibular first molar and sagittal sections of the mandibular tooth germ area were examined using immunohistochemical and immunofluorescence methods. For morphometric analysis, numbers of TRAP-positive cells were calculated against the total number of cells. In cross-sections from the experimental group, dentin was thickened and pulp tissue was constricted day by day. On days 1, 3 and 7, nestin-positive cells were observed in all odontoblast cell bodies and processes, while on day 14 fewer nestin-positive cells were seen than in the control group. On day 14, the mesial area of the periodontal ligament was constricted and the number of TRAP-positive cells in the mesial area was significantly higher than in the control group. In sagittal sections, enamel formation was found to be increased on days 7 and 14. Furthermore, in the enamel matrix amelogenin was expressed more strongly than in the control group. PCNA-positive cells were significantly increased in cells of the tooth germ compared with the control group. These results suggest that inhibition of tooth eruption accelerates the apical elongation with resorption of the mesial area of the alveolar bone and stimulates cell proliferation with thickened enamel towards the apical end.     

Extension of the Ring Oxygen Helicity Rule to Phenyl and p-Nitrophenyl Glycopyranosides

The Cotton effect below 200 nm was first studied in aromatic glycopyranosides with our new technique of optical rotatory dispersion (ORD). The phenyl and p-nitrophenyl α- and β-d-glycopyranosides showed a strong Cotton effect at around 180 nm which practically governed the optical rotations in the visible wavelength region. The rotational strength and sign of this Cotton effect were shown to reflect the anomeric configurations and conformations, which led to an extension of the ring oxygen helicity rule for alkyl and alkyl 1-thioglycosides to aromatic glycopyranosides.     

Application of Axial-haloketone Rule to Lactones

Antifungal activities were examined and compared for some 40 kinds of aliphatic and aromatic aldehydes, alcohols, phenolic compounds, ether compounds and hydrocarbons from essential oils and for some related compounds, using seven fungi.     

Studies on Chrysanthemic Acid

Pyrethrin II, cinerin II, allethrin II, pyrethrin II isomer, and allethrin II isomer were prepared by esterification of rethrolons with (+)-trans-pyrethric acid and (+)-trans-methyl-2,2-dimethyl-3-(2′-carboxy-l′-propenyl) cyclopropanecarboxylate and their relative toxicities to pyrethrin I, cinerin I and allethrin I against houseflies were measured by counting “mortality” and “knock-down percent”     

A Simple Determination Method for Herbicides,NIP and CNP in Soil Using Single Ion Monitoring Mass Spectrometry

A purified extracellular endo β-1,3-xylanase (EC 3.2.1.32) from an isolated strain, Aspergillus terreus A-07, was found to hydrolyze 1,3-xylosyl linkages only. When rhodymenan (β-1,4 and β-1.3-linked xylan) was hydrolyzed by β-1,3-xylanase (EF-6), four β-1,4-linked xylooligosaccharide fractions were produced. The main product was β-1,4-xylotriose, with trace amounts of other β-1,4-linked xylooligosaccharides. Successive degradation by β-l,4-xylosidase of the β,4-xylooligosaccharides that were produced from hydrolysis of β-1,3-xylanase on rhodymenan yielded only xylose as the final product.

We compared the action pattern of this enzyme with that of an extracellular endo β-l,4-xylanase (EC 3.2.1.8) of Streptomyces. From a mixture of products of β-1,4-xylanase hydrolysis on rhodymenan, an isomeric xylotriose was isolated by charcoal chromatography after treating with β-1.4-xylosidase. The structure of this isomeric xylotriose was elucidated by methylation analysis and its susceptibility to β-1,4-xylanase, β-1,3-xylanase, and β-1,4-xylosidase. The obtained isomeric xylotriose was identified as 3-O-β-xylopyranosyl-4-O-β-D-xylopyranosyl-D-xylose (X1→3X1→4X). It has a melting point of 224~225°C and ${\left[\alpha \right]}_{\text{D}}^{20}$(c = 1, H₂O)= —46°.     

Photobromination of 1,5-Anhydro-2,3-O-isopropylidene-β-d-ribofuranose and Synthesis of (5R) and (5S)-(5-2H1)-d-Riboses

The photobromination of 1,5-anhydro-2,3-O-isopropylidene-β-d-ribofuranose gave the corresponding (5S)-5-bromo compound. The reduction of the bromide with triphenyltindeuteride gave (5S)-(5-²H₁)-1,5-anhydro-2,3-O-isopropylidene-β-d-ribofuranose, with a chiral purity of 76% at C-5, which was converted to (5R)- and (5S)-(5-²H₁)-d-riboses and other ribofuranose derivatives.     

Summed Probability Distribution of 14C Dates Suggests Regional Divergences in the Population Dynamics of the Jomon Period in Eastern Japan

Recent advances in the use of summed probability distribution (SPD) of calibrated ¹⁴C dates have opened new possibilities for studying prehistoric demography. The degree of correlation between climate change and population dynamics can now be accurately quantified, and divergences in the demographic history of distinct geographic areas can be statistically assessed. Here we contribute to this research agenda by reconstructing the prehistoric population change of Jomon hunter-gatherers between 7,000 and 3,000 cal BP. We collected 1,433 ¹⁴C dates from three different regions in Eastern Japan (Kanto, Aomori and Hokkaido) and established that the observed fluctuations in the SPDs were statistically significant. We also introduced a new non-parametric permutation test for comparing multiple sets of SPDs that highlights point of divergences in the population history of different geographic regions. Our analyses indicate a general rise-and-fall pattern shared by the three regions but also some key regional differences during the 6^th millennium cal BP. The results confirm some of the patterns suggested by previous archaeological studies based on house and site counts but offer statistical significance and an absolute chronological framework that will enable future studies aiming to establish potential correlation with climatic changes.