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High Turnover Numbers for the Catalytic Selective Epoxidation of Alkenes with 1 atm of Molecular Oxygen We acknowledge T. Hayashi (The University of Tokyo), M. Wada (Nippon Shokubai Co., Ltd.), and Y. Sumita (Nippon Shokubai Co., Ltd.) for their help with experiments. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Sports and Culture of Japan.

Yoshiyuki Nishiyama、Yoshinao Nakagawa、Noritaka Mizuno2001-10-01Angewandte Chemie International Edition

The diiron-substituted silicotungstate γ-SiW10{Fe3+(OH2)}2O386− (schematically shown) is an effective catalyst for the oxygenation of alkenes in homogeneous reaction media with 1 atm of molecular oxygen. For example, a selectivity for cyclooctene oxide of 98 % and a turnover number of 10 000 were achieved in the epoxi…

Oxidative Organic Chemistry ReactionsPolyoxometalates: Synthesis and ApplicationsChemical Synthesis and Reactions

Microspectroscopy and imaging using a delay line detector in time-of-flight photoemission microscopy

A. Oelsner、O. Schmidt、M. Schicketanz 等 8 位作者2001-10-01Review of Scientific Instruments

A method for microspectroscopy and energy-selective imaging using a special photoemission electron microscope (PEEM) is presented. A modified commercial PEEM was combined with a delay line device as x, y, t detector serving as the basic arrangement for spectromicroscopy. One can measure the time of flight of the elect…

Electron and X-Ray Spectroscopy TechniquesNear-Field Optical MicroscopyAdvanced Electron Microscopy Techniques and Applications

Ultrasound Enhanced Adsorption and Desorption of Phenol on Activated Carbon and Polymeric Resin

Brandon S. Schueller、Ralph T. Yang2001-10-01Industrial & Engineering Chemistry Research

The effects of ultrasound on the adsorption and desorption of phenol using activated carbon and polymeric resin was investigated. For adsorption in a batch adsorber, ultrasound was found to act like a mixer, improving the mass-transfer coefficient through cavitation and acoustic streaming. The mass-transfer coefficien…

Aerosol Filtration and Electrostatic PrecipitationElectrostatics and Colloid InteractionsUltrasound and Cavitation Phenomena

Structure of β-Ketoacyl-[acyl carrier protein] Reductase from Escherichia coli: Negative Cooperativity and Its Structural Basis,

Allen C. Price、Yongmei Zhang、Charles O. Rock 等 4 位作者2001-10-01Biochemistry

The structure of beta-ketoacyl-[acyl carrier protein] reductase (FabG) from Escherichia coli was determined via the multiwavelength anomalous diffraction technique using a selenomethionine-labeled crystal containing 88 selenium sites in the asymmetric unit. The comparison of the E. coli FabG structure with the homolog…

Protein Structure and DynamicsEnzyme Structure and FunctionMass Spectrometry Techniques and Applications

LIBERATION OF 5,8,11,14,17‐EICOSAPENTAENOIC ACID AND OTHER POLYUNSATURATED FATTY ACIDS FROM LIPIDS AS A GRAZER DEFENSE REACTION IN EPILITHIC DIATOM BIOFILMS

Friedrich Jüttner2001-10-01Journal of Phycology

Acute grazer toxicity of freshwater diatom biofilms was determined using Thamnocephalus platyurus Packard, an anostracan grazer, as the bioassay organism. The diatoms exhibited toxicity when the cells of the biofilm were freeze–thawed before the assay. The toxicity could be extracted from the biofilms with methanol an…

Environmental Chemistry and AnalysisDiatoms and Algae ResearchEnvironmental Toxicology and Ecotoxicology

Human Transferrin Receptor Gene as a Marker Gene for MR Imaging

Anna Moore、Lee Josephson、Rajeev Bhorade 等 5 位作者2001-10-01Radiology

PURPOSE: To quantitate and characterize the expression of an engineered human transferrin receptor (ETR) as a marker gene by using magnetic resonance (MR) imaging. MATERIALS AND METHODS: Rat gliosarcoma 9L cells stably expressing ETR (ETR+) were used, with nontransfected (ETR-) cells serving as controls. A conjugate o…

Lanthanide and Transition Metal ComplexesNanoparticle-Based Drug DeliveryAdvanced MRI Techniques and Applications

Baseline Studies of the Clay Minerals Society Source Clays: Layer-Charge Determination and Characteristics of Those Minerals Containing 2:1 Layers

A. R. Mermut、G. Lagaly2001-10-01Clays and Clay Minerals

The layer charge is perhaps the single most significant characteristic of 2: 1 layer phyllosilicates. Layer charge affects cation-retention capacity and adsorption of water, and various polar organic molecules. The effects of layer charge on the sorptive properties of organo- clays were illustrated by Lee et al. (1990…

Clay minerals and soil interactionsIron oxide chemistry and applicationsSoil and Unsaturated Flow

Infrared spectroscopy study of low-dielectric-constant fluorine-incorporated and carbon-incorporated silicon oxide films

Yoon-Hae Kim、Moo Sung Hwang、Hyeong Joon Kim 等 5 位作者2001-10-01Journal of Applied Physics

Bonding characteristics of low-dielectric-constant (low-k) fluorine-incorporated silicon oxide (SiOF) and carbon-incorporated silicon oxide (SiOC) films prepared by plasma enhanced chemical vapor deposition were investigated by Fourier transform infrared spectroscopy (FTIR). The frequency of Si–O stretching vibration…

Thin-Film Transistor TechnologiesSemiconductor materials and devicesCopper Interconnects and Reliability

Studies on Wall-Slip in Entangled Polymeric Liquids

Joshi Yogesh M.2001-10-01Applied Rheology

In this work, it is attempted to theoretically understand the phenomenon of wall slip through empirical and molecular models. Initially, we use the framework a transient network theory. We show that the severe disentanglement in the interfacial region can give rise to non-monotonic flow curve locally in that region. F…

Leaching of a gold bearing partially roasted sulphide. Laboratory scale studies

M.F. Almeida2001-10-01Materials Research

This research aimed at defining a route for recovering precious metals from a very heterogeneous gold bearing sulphide and arsenide concentrate that was partially roasted and dumped by the 1960s when Santo António mine closed. Gold occurs in this concentrate as free particles in the range of 10-100 mum, most of them s…

Evaluation of paper industry wastes in construction material applications

Enori Gemelli、Nelson Heriberto Almeida Camargo、Janaína Brescansin2001-10-01Materials Research

The influence of the application of residues from the cellulose and paper industry in construction mortar was investigated. Mortars were prepared with CPI-S-32 or CPII-Z-32 Portland cements and sand in a 1:3 proportion. Four solids residues, i.e., Fiber, Dregs, Bottom Ash and Grit, were incorporated in the mortars in…

Assessing wear and surface roughness of different composite resins after toothbrushing

D.T. Chimello、R.G.P. Dibb、S.A.M. Corona 等 4 位作者2001-10-01Materials Research

The aim of this work was to compare the in vitro wear and roughness of different composite resins after toothbrushing. Six resins were tested: Revolution (Kerr), Natural Flow (DFL), Flow It! (Jeneric-Pentron), Fill Magic Flow (Vigodent) - flowable composites, Silux Plus (3M) - microfilled composite, and Z100 (3M) - hy…

Dynamic Viscoelastic Properties of Organic / Inorganic Fibres Reinforced lldpe Composites in Molten State

Kitano Takeschi、Hashmi S.A.R.、Chand Navin2001-10-01Applied Rheology

Dynamic rheological parameters such as storage modulus, G’, loss modulus, G”, and dynamic viscosity, h’, at 200°C were studied for Kevlar fibres, glass fibres and their hybrids reinforced linear low density polyethylene (LLDPE). Parallel plate rheometer was employed for these tests. G’, G” and h’ increased with the in…

Vane Sensor System in Small Strain Oscillatroy Testing

Junus Silvara、Briggs Jenni L.2001-10-01Applied Rheology

To overcome difficulties (slip, sample disturbance) associated with traditional sensors, a semi-empirical method was developed to allow the use of a 4-bladed vane sensor in small strain oscillatory testing. It was assumed that the vane sensor acted as a bob with an acting radius, RV, different from the actual radius o…

Using the Microsoft Excel ‘Solver’ Tool to Perform Non-Linear Curve Fitting, Using a Range of Non-Newtonian Flow Curves as Examples.

Roberts G.P.、Barnes H.A.、Mackie C.2001-10-01Applied Rheology

The Microsoft Excel ‘Solver’ tool is a very simple but powerful procedure, even in the hands of the mathematically disadvantaged. It has very good application for quickly fitting experimental flow-curve data to non-Newtonian flow models with any number of parameters, and can cope with data from a number of sources. Ex…

Naturaleza y formación de los complejos intermedios del sistema SnCl2 - NH4OH - H2O

A. Ortiz、M. Mendoza、J.E. Rodríguez Paez2001-10-01Materials Research

Current technological advances require that the raw materials used in the production of electric devices and structural materials present special characteristics of chemical purity, size distribution and morphology of the particles. Tin oxides are mainly used as gas sensor and as surges suppressor (varistor). To achie…

A procedure to estimate the dynamic damped behavior of fiber reinforced composite beams submitted to flexural vibrations

Volnei Tita、Jonas de Carvalho、João Lirani2001-10-01Materials Research

This work proposes a procedure to estimate the dynamic damped behavior of fiber reinforced composite beams in flexural vibrations. A set of experimental dynamic tests were carried out in order to investigate the natural frequencies and modal shapes. These results are used to evaluate the damping factors by the program…

Estudio de la formacion de los complejos intermedios durante la sintesis de alumina

J.E. Rodríguez-Páez、C. Villaquirán、J. Cobo2001-10-01Materials Research

One of the most important compounds that are used in structural ceramics is alumina. During the last years, a variety of synthesis methods have been developed to obtain raw materials with suitable characteristics in terms of particle composition, size and shape. Controlled precipitation method (CP) allows to reach the…