Analysis of upgraded solvent-refined coal (SRC) liquid products

Upgraded coal-derived liquids obtained from catalytic hydroprocessing of a 30–70(wt%) blend of SRC-1 with SRC-II have been studied by infrared and proton magnetic resonance spectroscopy, and gel permeation chromatography techniques. Compared with the feed blend, the upgraded liquids exhibit a lower C/H ratio and decreased aromatic, heteroatom and pentane-insoluble contents, along with decreased specific gravity and viscosity. The amount of hydrogen-bonded structure in the upgraded liquid decreases with increases in residence time and processing temperature. The pseudo-first-order disappearance of phenolic OH and total nitrogen during processing indicates a relative reactivity of 2:1 of hydroxyl oxygen removal to total nitrogen removal in the upgrading process. Conversion of pentaneinsolubles to soluble oil also follows a pseudo-first-order reaction; under mild processing conditions, the heteroatom functionalities play a dominant role in the ease and extent of this conversion. Higher temperatures increase thermal cracking and hydrocracking of the ring structure resulting in more conversion of asphaltene to oil. The linear dependence of the logarithm of viscosity on the content of heteroatoms and toluene-insolubles (TI) indicates the importance of molecular interactions involving polar functional groups in defining the viscosity of coal-derived liquid.     

Dynamic mechanical properties of photopolymerizable poly(vinyl alcohol)–acrylate monomer blends

Dynamic mechanical properties of photopolymerizable poly(vinyl alcohol) (PVA)–monoacrylate blends were investigated by measuring dynamic shear modulus G′ and loss tangent, tan δ. The dynamic mechanical properties of the blends before being exposed to UV irradiation were governed by the weight percent of the monomers which act as plasticizers. On the other hand, the UV-irradiated blends seemed to be typical two-phase materials since they revealed two tan δ maxima whose positions were independent of the monomer content. Those two maxima were assigned to PVA and photopolymerized acrylates with reference to the dynamic mechanical data of PVA and a PVA-polyacrylamide polyblend. Those dynamic mechanical data suggested that insolubilization of the blend type photopolymers should be caused by a decrease in solubility due to graft polymerization of acrylate monomers onto PVA.     

Recognition of substrates by membrane potential of immobilized glucose oxidase membranes

The shifts in membrane potential, caused by the injection of glucose into a permeation cell, were measured using immobilized (entrapped) glucose oxidase membranes. No, pH change in the permeation cell was observed upon injection of glucose, but the shift in membrane potential was definitely detected. The shift in membrane potential was observed under nitrogen bubbling (in the absence of oxygen) using initially used enzyme membranes. It was, therefore, suggested that the shifts in membrane potential were not caused by an enzyme-substrate reaction, but by binding of the substrate to the enzyme, which indues a conformational change in the enzyme and leads to a change in charge density in the enzyme membrane. This mechanism is also supported by the fact that the shifts in membrane potential were observed upon injection of not only D-glucose but also L-glucose as reported in our previous study [J. Chem. Soc. Faraday Trans., 87 , 695 (1991)]. © 1994 John Wiley & Sons, Inc.     

A Novel Preparation Method for Foamed Silica Ceramics by Sol-Gel Reaction and Mechanical Foaming

A simple method for obtaining silica foam has been developed by combining sol-gel reaction and mechanical foaming without added organic pore formers, in order to reduce generation of CO₂ and harmful gases by decomposition of the organic compounds. The silica foam was prepared by mechanically foaming the silica sol and controlling the viscosity change and gelling. The gelation time of the silica sol can be varied from 10 minutes to 3 hours by changing the pH, temperature and concentration of the surfactant added as a foam stabilizer. The dried silica gel foam was calcined at 600°C then fired at 1000°C to obtain sintered silica foam. The porosity and average pore size of the silica foam was 84% and 140 m, respectively. The bending strength and gas permeability of the sintered silica foam was 2.4 MPa and 9.4 × 10^–11 m², respectively.     

Stereoselective partitioning of organic substrates by thermoresponsive polymers in aqueous phases

Partitioning of organic substrates by thermoresponsive polymer having N‐acryloylaminoalcohol moieties in aqueous phase has been studied. Thermoresponsive polymers, such as poly(N‐isopropylacrylamide) (PNIPAAm) and poly(NIPAAm‐co‐N‐acryloyl‐(±)‐alaninol) (poly(NIPAAm‐co‐HIPAAm)), were found to concentrate several organic substrates into the hydrophobic field generated during their phase transition. The amount of the substrates recoverd from the polymer phase mainly depended on the hydrophobicity of the substrates. Aqueous solutions of PNIPAAm (lower critical solution temperature, LCST = 33°C) and poly(NIPAAm‐co‐HIPAAm) (LSCT = 41°C) containing 1‐phenylethanol showed LCSTs at 22°C and 33°C, respectively. The changes of LCSTs indicate that specific interactions such as hydrogen bonding between the side chain functionalities of the polymers and the substrates influence the phase transition behavior. Moreover, new optically active polymers having chiral aminoalcohol moieties have been synthesized by copolymerizations of NIPAAm with N‐acryloylaminoalcohols such as N‐acryloyl‐(S)‐alaninol and N‐acryloyl‐(S)‐prolinol. The (R)/(S) ratio of 1‐phenylethanol recovered from poly(NIPAAm‐co‐N‐acryloyl‐(S)‐alaninol) and poly(NIPAAm‐co‐N‐acryloyl‐(S)‐prolinol) were determined to be 75/25 and 68/32, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3458–3464, 2013     

Surface modification of contact lenses using adsorption of ethylene oxide branched copolymers

To examine methods for reducing the amount of adsorbed protein on the surface of contact lenses during use, cationic copolymers containing poly(ethylene oxide) units were synthesized and evaluated as surface modifiers. Poly(ethylene oxide) graft‐branched copolymers of composition 70 mol % dimethylaminoethyl methacrylate (DM) and 30 mol % methoxy polyethylene glycol methacrylate (Mp0G; p = 2, 4, 9; the average number of the ethylene oxide units) were obtained using nonionic monomers containing poly(ethylene oxide) units. The copolymers very efficiently prevented protein adsorption on a contact lens. Contact angle measurements showed that immersion in tear fluid made the lens surface hydrophobic because of adsorption of proteins with hydrophobic residues. The copolymer pretreatment made the lens surface hydrophilic, even after dipping in artificial tear fluid. These results suggest that adsorption of the poly(ethylene oxide) branched copolymer on the contact lens would make the lens surface hydrophilic and prevent protein adsorption. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Sequential slippage tests using Robbins-Lai's invariant confidence sequences

The paper deals with two kinds of location-slippage testing problems.The alternative hypothesis says that there is a single slippage in one kind of problems,and that there are multiple slippages in the other kind. In a location slippage model, by using Robbins' inequality, Robbins-Lai's invariant confidence sequences for slippage are constructed for both of the problems and sequential slippage tests using those confidence sequences are proposed.     

miR-29 Represses the Activities of DNA Methyltransferases and DNA Demethylases

Members of the microRNA-29 (miR-29) family directly target the DNA methyltransferases, DNMT3A and DNMT3B. Disturbances in the expression levels of miR-29 have been linked to tumorigenesis and tumor aggressiveness. Members of the miR-29 family are currently thought to repress DNA methylation and suppress tumorigenesis by protecting against de novo methylation. Here, we report that members of the miR-29 family repress the activities of DNA methyltransferases and DNA demethylases, which have opposing roles in control of DNA methylation status. Members of the miR-29 family directly inhibited DNA methyltransferases and two major factors involved in DNA demethylation, namely tet methylcytosine dioxygenase 1 (TET1) and thymine DNA glycosylase (TDG). Overexpression of miR-29 upregulated the global DNA methylation level in some cancer cells and downregulated DNA methylation in other cancer cells, suggesting that miR-29 suppresses tumorigenesis by protecting against changes in the existing DNA methylation status rather than by preventing de novo methylation of DNA.     

Enhanced Development of Azoxymethane-Induced Colonic Preneoplastic Lesions in Hypertensive Rats

Metabolic syndrome is associated with an increased risk of colorectal cancer. This study investigated the impact of hypertension, a component of metabolic syndrome, on azoxymethane (AOM)-induced colorectal carcinogenesis using SHRSP/Izm (SHRSP) non-diabetic/hypertensive rats and SHRSP.Z-Lepr^fa/IzmDmcr (SHRSP-ZF) diabetic/hypertensive rats. Male 6-week-old SHRSP, SHRSP-ZF, and control non-diabetic/normotensive Wister Kyoto/Izm (WKY) rats were given 2 weekly intraperitoneal injections of AOM (20 mg/kg body weight). Two weeks after the last injection of AOM, the SHRSP and SHRSP-ZF rats became hypertensive compared to the control WKY rats. Serum levels of angiotensin-II, the active product of the renin-angiotensin system, were elevated in both SHRSP and SHRSP-ZF rats, but only the SHRSP-ZF rats developed insulin resistance, dyslipidemia, and hyperleptinemia and exhibited an increase in adipose tissue. The development of AOM-induced colonic preneoplastic lesions and aberrant crypts foci, was significantly accelerated in both SHRSP and SHRSP-ZF hypertensive rats, compared to WKY normotensive rats. Furthermore, induction of oxidative stress and exacerbation of inflammation were observed in the colonic mucosa and systemically in SHRSP and SHRSP-ZF rats. Our findings suggest that hypertension plays a role in the early stage of colorectal carcinogenesis by inducing oxidative stress and chronic inflammation, which might be associated with activation of the renin-angiotensin system.