Effects of dressing containing plant sterol on serum cholesterol concentration and the safety evaluation in borderline or mildly hypercholesterolemic Japanese subjects

In a placebo-controlled double-blind study, we examined the effects of dressing containing plant sterol (PS) on blood lipids and the safety in Japanese borderline or mildly hypercholesterolemic subjects. Fifty-nine subjects [total cholesterol (TC) concentration > or = 200 mg/dL] were randomly divided into two groups and were given daily 15 g of dressing containing 800 mg of PS [PS(+)-group] or without PS [PS(-)-group] for 12 weeks. Every 4 weeks, fasting blood was examined and subjective symptoms were analyzed. Serum TC, low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (ApoB) concentrations did not change in the PS(-)-group, while TC and ApoB significantly decreased in the PS(+)-group at 8 and 12 weeks and LDL-C at 4, 8 and 12 weeks. Moreover, serum TC, LDL-C and ApoB concentrations were significantly lower than those of PS(-)-group at 8 and 12 weeks. Other laboratory tests were all in normal ranges and no adverse events were observed. The results indicated that PS-containing dressing decreased serum TC, LDL-C and ApoB concentrations in borderline or mildly hypercholesterolemic subjects. It is therefore proved that the dressing containing PS is helpful in maintaining blood cholesterol level normal and hence, the health of Japanese.     

Colorless polyimides with low coefficient of thermal expansion derived from alkyl‐substituted cyclobutanetetracarboxylic dianhydrides

Alkyl‐substituted cyclobutanetetracarboxylic dianhydrides (CBDAs) were synthesized by photo‐dimerization of alkyl‐substituted maleic anhydrides to obtain novel colorless polyimides (PIs). Dimethyl‐substituted CBDA (DM‐CBDA) showed much higher polymerizability with various diamines than conventional cycloaliphatic tetracarboxylic dianhydrides and led to high molecular weights of PI precursors. Polyaddition of non‐substituted CBDA and trans‐1,4‐cyclohexanediamine (t‐CHDA) was completely inhibited by salt formation in the initial reaction stage. The use of DM‐CBDA allowed the formation of a homogeneous/viscous PI precursor solution by overcoming the salt formation problem. The prominent substituent effect probably reflects how the methyl substituents of DM‐CBDA contributed to increasing the salt solubility. Some of the thermally imidized DM‐CBDA‐based systems simultaneously possessed non‐coloration, low coefficient of thermal expansion (CTE), very high T_g exceeding 300 °C and very low dielectric constant. Copolymerization was very effective for improving the solubility of DM‐CBDA‐based PIs. The copolyimide cast films prepared via chemical imidization displayed a further decreased CTE without sacrificing other target properties, suggesting that the present materials can be useful as plastic substrates in display devices. The mechanism of self‐chain orientation behavior during solution casting is also discussed. A potential application of the copolyimide systems as optical compensation film materials in liquid crystal displays is proposed. © 2013 Society of Chemical Industry .     

Enhanced Light Storage of SrAl2O4 Glass‐Ceramics Controlled by Selective Europium Reduction

A luminescent Eu, Dy: SrAl₂O₄ glass‐ceramics with high transparency in the visible region was successfully synthesized using the frozen sorbet technique with the control of O₂ partial pressure () for the oxidation of Eu²⁺ ions. The glass‐ceramics include Eu²⁺, Eu³⁺, and Dy³⁺ ions, and thus exhibits three characteristic types of emission bands, 4f–5d at around 520 nm (Eu²⁺ ions), 4f–4f at 610 nm (Eu³⁺ ions), and 480 nm (Dy³⁺ ions). The Eu, Dy: SrAl₂O₄ glass‐ceramics provide remarkable long‐persistent luminescence under dark condition. The glass‐ceramics also exhibits color‐changing luminescence in the visible region based on their remarkable light storage properties. The luminescent Eu, Dy: SrAl₂O₄ glass‐ceramics using the frozen sorbet technique with control of are promising materials for application in novel photonic and light storage materials.     

Cell distributions in and sound absorption characteristics of flexible polyurethane foams

In this article, the two-dimensional distributions of cells from the cross section of some flexible polyurethane foams were cleared, and the three-dimensional distributions of cells based on Saltykov's theory were estimated further. As a result, it was found that a mean of the two-dimensional distributions of cells was a good linear relation with a mean of the three-dimensional distributions of cells, and it was confirmed that cell structure of the foams which should have been analyzed in the three-dimensional distributions was evaluated by analysis of the two-dimensional distributions fully. It was also found that not only cell number but also cell distribution was necessary in the evaluation of flexible polyurethane foams, and cell diameter was closely related to the sound absorption coefficient in polyester-based flexible polyurethane foams. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1395–1402, 1997     

γ‐Butyrolactone‐processable high‐modulus poly(ester imide)s

γ‐Butyrolactone (GBL)‐processable high modulus heat‐resistant materials were developed in this work. The polyaddition of an ester‐containing tetracarboxylic dianhydride, i.e. hydroquinone bis(trimellitate anhydride) (TAHQ), and 2,2′‐bis(trifluoromethyl)benzidine (TFMB) in GBL resulted in gelation in the initial reaction stage. The incorporation of a methyl group to TAHQ (M‐TAHQ) allowed polymerization with TFMB in GBL and led to a homogeneous poly(ester imide) (PEsI) precursor solution with a short pot life of 3 days, whereas a simple copolymerization approach using bulky/flexible comonomers to TAHQ/TFMB was less effective. PEsI precursors (PEsAAs) were prepared from TFMB, M‐TAHQ and a minor fraction of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) or a fluorene‐containing tetracarboxylic dianhydride. These PEsAA systems showed drastically improved GBL solution stability. In particular, the M‐TAHQ(80);6FDA(20)/TFMB copolymer system provided a PEsAA film with a very high light transmittance at 365 nm (>70%). A photosensitive film composed of this matrix resin and diazonaphthoquinone provided a clear positive‐tone pattern by development in a 2.38 wt% tetramethylammonium hydroxide aqueous solution at room temperature with a high dissolution contrast. The thermally cured PEsI film achieved a very high tensile modulus (>5 GPa) as the present target with other desirable properties, i.e. sufficient film flexibility, a relatively low coefficient of thermal expansion, a high T_g and low water absorption. The present materials can be promising candidates as novel buffer coat films in semiconductor applications. Copyright © 2011 Society of Chemical Industry     

Synthesis of stable and soluble one-handed helical poly(substituted acetylene)s without chiral pendant groups via polymer reaction in membrane state

A soluble and stable one-handed helical conjugated polymer without the coexistence of any other chiral moieties was successfully synthesized by asymmetric-induced polymerization of a chiral monomer having two hydroxyl groups followed by desubstitution of the chiral groups in a solid membrane state. The reason for the success was the polymer reaction was carried out in the membrane state. This is an alternative method to obtain such a unique chiral polymer which was obtained only by the helix-sense-selective polymerization (HSSP) we reported before. In addition the efficiency of the chiral induction was higher than that of the HSSP. It is interesting that the “Membrane state” acted like as if a protecting group.     

Preparation of bismuth nanowire encased in quartz template for Hall measurements using focused ion beam processing

ABSTRACT: Forming electrodes on opposite sides of an individual bismuth nanowire was attempted to prepare for Hall measurements. Although a 1-mm-long bismuth nanowire which is completely covered with a quartz template has been successfully fabricated to prevent oxidation, it is very difficult to attach Hall electrodes on the opposite sides of the nanowire due to the quartz covering. One side of the cylindrical quartz template was removed by polishing without exposure of the nanowire to the atmosphere; the thickness between the polished template surface and the nanowire was estimated to be several micrometers. Focused ion beam processing was successfully employed to expose both surfaces of the nanowire under high vacuum by removing part of the quartz template. A carbon thin film was then deposited in situ on the wire surface to fabricate an electrical contact on the bismuth nanowire sample. Furthermore, the energy dispersive X-ray analysis was performed to the area processed by focused ion beam, and the bismuth component of the nanowire was successfully detected. It was confirmed that the focused ion beam processing was applicable to attach electrodes to bismuth nanowire for Hall measurement.     

陶瓷色料中添加发色离子的状态与反应

固体滴定法是研究固溶量的一种新方法。本实验选择Mn-Al2O3色料,给其中加入Cr2O3,通过测定反射光谱f(R)、晶格常数、电子自旋共振（ESR）,并计算晶格常数,分别得到加入Cr2O3前后的Mn-Al2O3的反射光谱与晶格常数的变化,依据该数据来推定着色离子Mn的固溶量及化学状态。为研究Mn-Al2O3红色料中Mn的固溶量,给其中加入Cr2O3,它使Mn-Al2O3红的色调发生变化,在此过程中发生如下反应：Cr^3 Mn^3 →Cr^4 Mn^2 ,Mn-Al2O3红色料在反射光谱520nm处有吸收峰值,给其中添加Cr2O3后峰值减小,用Cr^3 的固溶量（即Cr2O3的添加量）和峰值Δf(R)作图并延伸图线至Δf(R)=0点,此点对应的Cr2O3值即为Mn^3 的固溶量（Mn2O3的浓度）。实验证明,利用固体滴定法在一定精度范围内测定发色元素的固溶量取得一定程度成功。锰红色料中的发色离子状态为Mn^3 ,添加Cr2O3后,Cr能置换Mn-Al2O3中的Mn。铬是以Cr^3 化学状态固溶到Al2O3中的。     

Dielectric response and polarization mechanism of alkali silicate glasses in gigahertz to terahertz frequency range

Oxide glasses are dielectric materials with potential applications in high-frequency communications; hence, their dielectric properties in the gigahertz to terahertz frequency range should be investigated. In this study, the dielectric properties of silica glass and five single alkali silicate glasses were measured at 0.5–10 THz using terahertz time-domain spectroscopy and far-infrared spectroscopic ellipsometry. At 0.5–10 THz, the silica glass exhibited low dielectric dispersion with a low dielectric constant and loss. By contrast, the alkali silicate glasses exhibited high dielectric dispersion, and the dielectric constant and loss were higher than those of the silica glass. The shape of the dielectric dispersion profile depended on the alkali-metal ions; it was broader for lighter ions such as Li ions and sharper for heavier ions such as Cs ions. The peak dielectric loss shifted toward a lower frequency as the weight of the alkali-metal ions in the alkali-silicate glass increased. To understand the dielectric dispersion, the complex permittivity was calculated using molecular dynamics simulations. The theoretical results qualitatively agreed with the experimental data. Ion dynamics analysis revealed that alkali-metal ions vibrate and migrate under an applied electric field, which affects the dielectric constant and loss of alkali-silicate glasses at gigahertz to terahertz frequencies. To fabricate filter devices at low temperatures, alkali metals should be added to silicate glass; therefore, a minimum amount of light alkali metals should be used to minimize the dielectric loss of the glass materials while maintaining productivity.