Concise synthesis of polymethoxyflavone sudachitin and its derivatives,and biological evaluations

We accomplished a divergent synthesis of sudachitin (2), a polymethoxyflavone isolated from citrus fruits, and six derivatives from acetophenone 9, which was an intermediate in our previous synthesis of nobiletin (1). Compound 2 enhanced glucose-induced insulin secretion in INS-1D cells, but was less potent than 1. Compared with 1, compound 2 and two derivatives were more potent inhibitors of cAMP-specific phosphodiesterase.     

Fast and slow dynamics in single and mixed alkali silicate glasses

A molecular dynamics (MD) simulation for single and mixed alkali metasilicates has been performed. The mixed alkali effect (MAE) in the diffusion coefficients is reproduced. The motion of lithium ions in Li₂SiO₃ can be divided into slow (type A) and fast (type B) categories clearly in the glassy state. It turns out that the slow dynamics are caused by localized jump motions with a long tail of the waiting time distribution. On the other hand, fast dynamics of the lithium ions are caused by successive cooperative jump motions and are identified as Lévy flights. The MAE in LiKSiO₃ occurs due to mutual interception of jump paths of both kinds of mobile ions. In such paths, the fast component is considerably suppressed. Namely, the cooperative forward-correlated jump process is sensitive to the blockage of the jump paths. Propagation of the immobilization in the MAE is discussed in relation with the mechanism of the cooperative jump motion. The ratio of the fast and slow dynamics plays an important role to determine the transport properties in the glassy state.     

Chlorine isotopic compositions of deep saline fluids in Ibusuki coastal geothermal region,Japan: using B–Cl isotopes to interpret fluid sources

We report chlorine stable isotopic compositions (δ³⁷Cl, expressed in ‰ relative to the standard mean ocean chloride) as well as δ²H and δ¹⁸O values of deep saline fluids taken at eight drill-holes reaching from 73 to 780?m below sea level in the Ibusuki coastal geothermal region, Japan. Analytical results show that the δ³⁷Cl values narrowly range between ?0.26 and +0.21?‰ with an analytical precision of ±0.06?‰. Except for one sample, the samples examined are negative in δ³⁷Cl value with varying Cl/B molar ratios from 117 to 1265. A correlation study between the Cl/B molar ratio and the δ³⁷Cl/δ¹¹B ratio indicates a hyperbola-type mixing of at least two Cl sources in the Ibusuki region. One of them depletes in ³⁷Cl with a higher value of Cl/B molar ratio; and the other one enriches in ³⁷Cl with a lower Cl/B molar ratio. The former is chemically identical to that of the deep brine, which is altered seawater through the seawater–hot rock interaction. The latter is chemically similar to gas condensate derived from the high-temperature (890?°C) vent of an island-arc volcano near the Ibusuki region.     

Confirmation that SNPs in the high mobility group‐A2 gene (HMGA2) are associated with adult height in the Japanese population; wide‐ranging population survey of height‐related SNPs in HMGA2

Adult height is a highly heritable trait in that multiple genes are involved. Recent genome‐wide association studies have identified a novel single‐nucleotide polymorphism (SNP) rs1042725 in the high mobility group‐A2 gene (HMGA2) and shown it to be associated with human height in Caucasian populations. We performed a replication study to examine the associations between SNPs in HMGA2 and adult height in the Japanese population based on autopsy cases. Although we could not confirm a significant association between rs1042725 in HMGA2 and adult height, another SNP, rs7968902, in the gene achieved significance for its association in the same populations, and the effect was the same as that documented previously. These findings permit us to conclude that the SNPs in HMGA2 are common variants influencing human height across different populations. Moreover, a worldwide population study of these SNPs using 14 different populations including Asians, Africans and Caucasians demonstrated that both haplotypes and genotypes for three height‐related SNPs (rs1042725, rs7968682 and rs7968902) in HMGA2 were distributed in an ethnicity‐dependent manner. This information will be useful for clarifying the genetic basis of human height.     

Preparation and Characterization of Phospha Sugar Analogues, 2,3-Dibromo-3-methyl-1- phenylphospholane 1-Oxide Derivatives,as Novel Anticancer Agents

The synthesis of new phospha sugar analogues or phosphorus heterocycles and their biological activities as novel anticancer agents are reported in this article. A 1,2-dibromo-1,2-dideoxy phospha sugar derivative, 2,3-dibromo-3-methyl-1-phenylphospholane 1-oxide (2), was prepared from 1-phenyl-3-methyl-2-phospholene 1-oxide (1), and the yield and ratio of diastereomers 2a to 2d were changed by a catalyst such as manganese(IV) oxide and manganese(II) bromide. The antitumor activities of the mixture of dibromides 2 and the separated diastereomeric components 2a to 2d of the dibromides were evaluated by MTT in vitro method against the human leukemia cell lines of K562 and U937. The results showed that all of the diastereomers 2a to 2d as well as the diastereomer mixture exert excellent anticancer activity, and moreover, among them, diastereomer 2d showed the highest antitumor activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Thermal diffusivity in femtosecond-laser-structured micro-volumes of polymers

Thermal diffusivity of laser micro-structured regions in plastics was determined using a temperature wave method with a lateral resolution reduced to ∼10 μm using an array of micro-sensors. A high volume fraction (>25%) of laser modified phase was recorded by tightly focused femtosecond-laser pulses inside films of poly-methylmethacrylate, non-oriented polyethylene, polystyrene, and polyimide-Kapton. Changes in thermal diffusivity inside the laser-structured volumes of the order of a few percent were reliably determined with the miniaturized sensors. The origin of the change of thermal properties in plastics is discussed.