Determination of the heat change in solvent extraction of metals. The extraction of zinc (II) from hydrochloric acid solutions by high molecular weight amines in various organic solvents

The heat change associated with the uptake of zinc (II) has been examined by using a twin type isoperibol calorimeter in the extraction of zinc (II) from hydrochloric acid solutions by trioctylamine hydrochloride (TOAHCl) and trioctylmethyl-ammonium chloride (TOMAC) in various organic solvents such as benzene, chlorobenzene, o-dichlorobenzene, toluene, m-xylene, nitrobenzene, carbon tetrachloride and 1, 2-dichloroethane. It was found that the dependence of apparent molar heat change (the value of the heat change detected with regard to the concentration of zinc (II) reacted) on the aqueous chloride concentration could be attributed to the change in the distribution of zinc (II) chloride species in the aqueous phase. Taking account of this fact, variable Y, which constitutes the sum of the change in enthalpies for the relevant steps in the extraction of zinc (II), except the transformation of ZnCl_j^(2-j)+ to ZnCl₄^2-, in the aqueous phase, is introduced. From the values of Y obtained, it is concluded that in the extraction by TOMAC, Y correlates with the solubility parameter of diluent, suggesting that the organic phases may be regarded as regular solutions, while in the extraction by TOAHCl, no clear-cut relation holds between Y and the physico-chemical constants of the diluent such as dipole moment, dielectric constant and solubility parameters.     

Operating experience on RO sea water desalination plant at chigasaki laboratory

A demonstration plant with a capacity of 800 m³/d has been operating satisfactorily in Chigasaki Laboratory since September 11, 1979. The plant has two sets of modules, namely hollow fiber and spiral wound types. These two types of modules have been operated alternately every other month, being supplied sea water from the same pretreatment facility and the same high pressure pump. The accumulated operation time of each module has exceeded 5,000 hours. The operation result shows high recovery ratio, low energy consumption and good quality of product water.     

Application of Optical-fiber Photoreactor for CO2 Photocatalytic Reduction

An optical-fiber photoreactor, comprised of 216 catalyst-coated fibers, was designed and assembled to transmit and spread light uniformly inside the reactor. The power loss of light transmission inside an optical fiber was calculated using beam propagation method. The optimum length of optical fiber was estimated to be near 11 cm long in order to entirely spread out light energy over surface catalyst. Vapor-phase CO₂ was photocatalytically reduced to methanol using the photoreactor under UV irradiation in a steady-state flow system. The solutions of metal-loaded titania were prepared by thermal hydrolysis method. Metal-loaded TiO₂ film was coated on optical fibers by dip-coating method. TiO₂, Cu/TiO₂ and Ag/TiO₂ films were uniformly on the fibers and their thicknesses ranged from 27 to 33 nm. The films consisted of very fine spherical particles with diameters of 10–20 nm. The XRD spectra indicated anatase phase for all films. Methanol yield increased with UV irradiative intensity. Maximum methanol rate was 4.12 μmole/g-cat h using 1.0 wt%-Ag/TiO₂ catalyst at 1.13 bar of CO₂, 0.03 bar of H₂O pressures, and 5,000 s mean residence time under 10 W/cm² UV irradiation.     

Effect of mixing conditions on the rheological and optical properties of chemically modified poly(ethylene terephthalate‐co‐ethylene isophthalate)

The optical properties and rheological properties were studied for binary reactive blends composed of poly(ethylene terephthalate‐co‐ethylene isophthalate) [P(ET–EI)] and a styrene–acrylate based copolymer with glycidyl functionality. The blade rotation speed in the internal mixer greatly affected the structure and properties for the blend system. Intensive mixing at a high rotation speed enhanced the optical transparency because of the reduced particle size of the dispersed phase. The graft copolymer generated by the reaction between P(ET–EI) and the modifier was responsible for the fine morphology. Furthermore, the copolymer also enhanced the elastic nature in the molten state because it acted as a long‐chain branched polymer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Elution-extrusion countercurrent chromatography: theory and concepts in metabolic analysis

Elution-extrusion countercurrent chromatography (EECCC) takes full advantage of the liquid nature of the stationary phase in CCC by combining regular chromatographic elution with stationary-phase extrusion. EECCC is shown to be a three-stage process consisting of classical elution (I), sweeping elution (II), and extrusion (III). After only two column volumes of solvent, it rapidly yields a high-resolution chromatogram that covers an extended polarity range of solutes. As hydrophilicity/lipophilicity balance is a crucial discriminatory property of analytes in highly complex mixtures such as metabolomic samples, the precise determination of CCC distribution constants (KD) is vital to the analysis of metabolomes and other complex biological matrixes. This work builds the EECCC concept by performing a full theoretical treatment and providing equations for retention volumes, peak widths, resolution factors, and distribution constants. Experimental validation utilizes natural products standards that resemble the zero to infinity range of the polarity continuum. EECCC extends the "sweet spot" of high resolution in CCC and provides access to the otherwise practically unapproachable high-KD portion of the high-resolution chromatograms in CCC. Its improved capabilities of KD targeting make EECCC a promising tool for the specific analysis of "small" molecules in complex samples such as in metabolomic fingerprinting and footprinting.     

Androgen Receptor Signaling Induces Cisplatin Resistance via Down-Regulating GULP1 Expression in Bladder Cancer

The underlying molecular mechanisms of resistance to cisplatin-based systemic chemotherapy in bladder cancer patients remain to be elucidated, while the link between androgen receptor (AR) activity and chemosensitivity in urothelial cancer has been implicated. Our DNA microarray analysis in control vs. AR knockdown bladder cancer lines identified GULP1 as a potential target of AR signaling. We herein determined the relationship between AR activity and GULP1 expression in bladder cancer cells and then assessed the functional role of GULP1 in cisplatin sensitivity. Androgen treatment in AR-positive cells or AR overexpression in AR-negative cells considerably reduced the levels of GULP1 expression. Chromatin immunoprecipitation further showed direct interaction of AR with the promoter region of GULP1. Meanwhile, GULP1 knockdown sublines were significantly more resistant to cisplatin treatment compared with respective controls. GULP1 knockdown also resulted in a significant decrease in apoptosis, as well as a significant increase in G2/M phases, when treated with cisplatin. In addition, GULP1 was immunoreactive in 74% of muscle-invasive bladder cancers from patients who had subsequently undergone neoadjuvant chemotherapy, including 53% of responders showing moderate (2+)/strong (3+) expression vs. 23% of non-responders showing 2+/3+ expression (P = 0.044). These findings indicate that GULP1 represents a key downstream effector of AR signaling in enhancing sensitivity to cisplatin treatment.     

Controlled radical polymerization of styrene utilizing excellent radical capturing ability of diphenyl ditelluride

Summary The radical polymerization of styrene was investigated in the presence of diphenyl ditelluride (DPDTe) under varied conditions. In the polymerization without any radical initiator at higher temperature (125°C), the addition of DPDTe surely decreased the polymer molecular weight (M _n) while the polydispersity (M _w/M _n) was rather broad. The polymerization with benzoyl peroxide (BPO) as the initiator was also uncontrollable to afford polymers with broad M _w/M _n probably due to the redox side reaction of BPO with DPDTe. On the contrary, the precision control of M _n and the initiating end structure could be achieved by the polymerization with 2,2'-azobisisobutyronitrile (AIBN), that is, M _n increased in proportion to the molar ratio of monomer to initiator suggesting the suppression of bimolecular chain termination reactions by the excellent radical capturing ability of DPDTe. Received: 23 June 1999/Revised version: 11 August 1999/Accepted: 16 August 1999     

Biodiesel fuel production from plant oil catalyzed by Rhizopus oryzae lipase in a water-containing system without an organic solvent

A new enzymatic method of synthesizing methyl esters from plant oil and methanol in a solvent-free reaction system was developed. It is anticipated that such plant oil methyl esters can be used as a biodiesel fuel in the future. Lipase from Rhizopus oryzae efficiently catalyzed the methanolysis of soybean oil in the presence of 4–30 wt% water in the starting materials; however the lipase was nearly inactive in the absence of water. The methyl ester (ME) content in the reaction mixture reached 80–90 wt% by stepwise additions of methanol to the reaction mixture. The kinetics of the reaction appears to be in accordance with the successive reaction mechanism. That is, the oil is first hydrolyzed to free fatty acids and partial glycerides, and the fatty acids produced are then esterified with methanol. Although R. oryzae lipase is considered to exhibit 1(3)-regiospecificity, a certain amount of 1,3-diglyceride was obtained during the methanolysis and hydrolysis of soybean oil by R. oryzae lipase solution. Therefore, the high ME content in the reaction mixture is probably attributable to the acyl migration from the sn-2 position to the sn-1 or sn-3 position in partial glycerides.