bluuebunny/crossref_metadata_2025_split huggingface dataset:
Titania-based heterogeneous photocatalysis. Materials, mechanistic issues, and implications for environmental remediation
Authors: Rajeshwar Krishnan , Chenthamarakshan C. R. , Goeringer Scott , Djukic Miljana 
Published: October 2007

Abstract
Using hexavalent chromium [Cr(VI)] and methylene blue (MB) as model substrates, we discuss three aspects of TiO2-based heterogeneous photocatalysis. We show first that a given TiO2 sample may not be simultaneously optimal for photocatalytically driving the reduction of Cr(VI) and the oxidation of MB. We further show that a TiO2 sample that strongly adsorbs either of these substrates in the dark is not optimal as a photocatalyst. The other two aspects concern circumventing the rather poor surface catalytic properties and visible light photoresponse of TiO2, respectively. Strategies revolving around the visible light photoexcitation of the substrate itself and metal-modification of the TiO2 surface, are described as possible solutions.
New inhibitors for copper corrosion
Authors: Vastag Gy. , Szöcs E. , Shaban A. , Kálmán E. 
Published: October 2007

Abstract
The study of the effectiveness of several potential copper corrosion inhibitors in acidic media was studied. The investigated thiazole derivative functional groups contain heterocyclic atoms such as nitrogen, sulfur, and oxygen. Thiazole derivatives, 5-benzylidene-2,4-dioxotetrahydro-1,3-thiazole (BDT) 5-(4¢-isopropylbenzylidene)-2,4-dioxotetrahydro-1,3-thiazole (IPBDT), 5-(3¢-thenylidene)-2,4-dioxotetrahydro-1,3-thiazole (TDT), and 5-(3¢,4¢-dimetoxybenzylidene)-2,4-dioxotetrahydro-1,3-thiazole (MBDT) were tested for copper corrosion inhibition properties. The electrolyte solution was 0.1 M Na2SO4.
In situ information on corrosion and inhibition processes can be obtained using different techniques. Electrochemical measurements (EIS), in situ scanning probe microscopy (SPM), in addition to quartz crystal microbalance (QCM) measurements were applied. Those methods are very useful owing to their high sensitivity and resolution. Dynamic STM and AFM measurements on Cu(111) single-crystal electrode with and without the addition of some inhibitors were performed.
The presence of the isopropyl group in the case of IPBDT produced far better protection against copper corrosion in acidic sulfate-containing media than the rest of the derivatives.
Intramolecular cyclization of propargyl derivatives using environmentally friendly methodologies
Authors: Duñach E. , Esteves A. P. , Freitas A. M. , Lemos M. A. , Medeiros M. J. , Olivero S. 
Published: October 2007

Abstract
The electrochemical intramolecular cyclization of propargyl derivatives containing a carbon­halogen bond in N,N'-dimethylformamide at constant current in a diaphragmless cell has been developed using Ni(II) complexes as electron-transfer mediators.
Degradation of dye effluent
Authors: Lorimer J. P. , Mason T. J. , Plattes M. , Phull S. S. , Walton D. J. 
Published: October 2007

Abstract
Solutions of both basic and acidic dyes were subject to sonolysis, electrolysis, and sonoelectrolysis. Only basic dyes were decolorized by ultrasound alone. Removal of the acidic dye Sandolan Yellow required the use of an electrooxidation process. The rate of electrochemical decolorization in the absence of ultrasound was dependent on the type of electrolyte, the electrolyte concentration, the reaction temperature, and the current density. The sonoelectrooxidation of Sandalon Yellow needed to be performed in a sealed cell to minimize the effects of ultrasonic degassing.
Direct electrochemistry of redox proteins or enzymes at various film electrodes and their possible applications in monitoring some pollutants
Authors: Hu Naifei 
Published: October 2007

Abstract
Water-insoluble films modified on the surface of solid electrodes may provide a unique microenvironment for electron transfer of some redox proteins or enzymes. The film materials can be two-tail surfactants, or composites of polyion-surfactant or clay-surfactant. Both surfactant and composite films cast on surface of electrodes are self-assembled into an ordered multibilayer structure, which is very similar to the bilayer structure of biological membrane. Amphiphilic polymers can also be used for making films. Incorporated heme proteins such as myoglobin (Mb), hemoglobin (Hb), or horseradish peroxidase (HRP) in these films demonstrated reversible voltammetry. Studies of direct electrochemistry of these proteins in various films by our group are reviewed in this paper. The protein films may provide a good model for study of electron transfer process in biological systems. The electrocatalytic properties of the protein films may also be applied to monitor some pollutant substrates.
Humic matter and contaminants. General aspects and modeling metal ion binding
Authors: Koopal Luuk K. , van Riemsdijk Willem H. , Kinniburgh David G. 
Published: October 2007

Abstract
Humic substances are soil and fresh-water components that play an important role in the binding and transport of both organic and inorganic contaminants. Transport of the contaminants due to ground- and fresh-water dynamics is directly related to the risks associated with contaminations. The mobility of soluble humic substances is related to their interaction with soil mineral particles. Some key references for the binding of organic and inorganic contaminants and for the binding of humics to mineral particles are presented. Humic substances also play a role in the analysis of the contaminants in natural waters and with remediation of water or soil polluted with pesticides, heavy metal ions, and radionuclides. These aspects are illustrated with some examples. The problems that are encountered with the modeling of the binding of contaminants to humics and of heavy metal ions in particular are illustrated by considering the nonideal competitive adsorption model (NICA) extended with electrostatic interactions. The NICA-Donnan model gives quite good results for the description of metal ion binding, as is illustrated for metal ion binding to purified peat humic acid (PPHA). Finally, some remarks are made with respect to the use of the NICA-Donnan model in general purpose speciation programs and of simplified versions of the model for predictions under restricted environmental conditions.
Effect of colloids on radionuclide migration for performance assessment of HLW disposal in Japan
Authors: Kurosawa S. , Ueta S. 
Published: October 2007

Abstract
Colloidal effect is one of the major factors to enhance the migration of radionuclides in groundwater. The experimental and theoretical studies of colloid mobility and colloid-facilitated radionuclide transport for the performance assessment of high-level radioactive waste (HLW) geological disposal is presented in this paper. The major aims of the study are (1) to study the filtration effect on colloids by the engineered barrier system, (2) to study bentonite colloid generation by erosion of the engineered barrier system, and (3) to calculate radionuclide migration with groundwater colloids through fractured rock systems.
Alternative coagulants based on prehydrolyzed forms of aluminium or iron can be more effective than the traditional materials in many cases, but their mode of action is not completely understood, especially with regard to the role of charge neutralization and hydroxide precipitation.
Basic principles of colloid stability and metal ion hydrolysis are briefly reviewed, and the action of hydrolyzing metal coagulants is then discussed, with some examples from recent experimental studies. Although it is possible to interpret results reasonably well in terms of established ideas, there are still some uncertainties that need to be resolved
Ruthenium catalysis in organic synthesis
Authors: Murahashi Shun-Ichi , Takaya Hikaru , Naota Takeshi 
Published: October 2007

Abstract
Ruthenium, rhodium, iridium, and rhenium hydride complexes are highly useful redox Lewis acid and base catalysts. Various substrates bearing hetero atoms are activated by these catalysts and undergo reactions with either nucleophiles or electrophiles under neutral conditions. These types of catalytic reactions are described together with their application to the preparation of various biologically active compounds.
Toward the ideal synthesis. New transition metal-catalyzed reactions inspired by novel medicinal leads
Authors: Wender Paul A. , Bi F. Christopher , Gamber Gabriel G. , Gosselin Francis , Hubbard Robert D. , Scanio Marc J. C. , Sun Robert , Williams Travis J. , Zhang Lei 
Published: October 2007

Abstract
Studies in our laboratory are directed at the advancement of synthesis, biology, and medicine. This lecture will focus on new transition metal-catalyzed reactions that have been inspired by biologically potent targets such as phorbol and Taxol® and by the more general interest in producing syntheses that are concise, efficient, cost- and resource-effective, environmentally benign, quick, and simple to conductin essence, ideal. A special emphasis in our program is placed on new transition metal-catalyzed reactions that, in the absence of catalyst, would be forbidden or difficult to achieve. We have thus far reported the first examples of intramolecular metal-catalyzed [4+2], [5+2], and [4+4] cycloadditions, reactions that produce 6-, 7-, and 8-membered rings, respectively. Recent advances in our [5+2] cycloaddition studies will be presented, including new catalysts for relative and absolute stereochemical control. We will also describe recyclable catalysts that can be used in water, thereby minimizing cost and environmental concerns about solvent waste streams. New multicomponent reactions will also be presented. Finally, we will report a new [6+2] cycloaddition that produces an 8-membered ring.
Arene chromium complexes with functionalized anellated rings. Selective formation of highly substituted polycycles
Authors: Butenschön Holger 
Published: October 2007

Abstract
Tricarbonylchromium complexes of benzocyclobutenone, benzocyclobutenedione, and 1,3-indandione are readily prepared by hydrolysis of the complexes of the corresponding acetals. Reduction of the benzocyclobutenone complex gives rise to an oxy-anion-driven ring opening to the corresponding ortho-quinodimethane intermediate, which can be trapped with dienophiles. Addition of 1-ethoxy-1-lithioethene allows a stereoselective ring expansion followed by an anionic ketol rearrangement with complete diastereoselectivity. Addition of 1-lithio-1-methoxyallene gives rise to a rare anionic 1-vinylcyclobutenol-cyclohexadienol rearrangement. Diaddition of alkenylmetal reagents at both keto groups in benzoyclobutenedione complexes causes dianionic oxy-Cope rearrangements to occur at ­78 °C, which are followed by diastereoselective intramolecular aldol additions. In some cases, a completely regioselective mono hydrolysis of di(enolates) was observed. Dianionic oxy-Cope rearrangements can also be realized with unstrained benzil derivatives giving 1,6-hexanediones and the corresponding aldol adducts. The 1,2,3-indantrione complex is obtained by oxidation of the 1,3-indandione complex with dimethyldioxirane in good yield and reacts with its central ketone group in hetero Diels­Alder cycloadditions.
Selective organometallic syntheses from molecular pools
Authors: Catellani Marta 
Published: October 2007

Abstract
A new methodology is described, consisting of the use of molecular pools in palladium-catalyzed sequential processes occurring under mild conditions with high selectivity. These reactions involve palladacycle formation from aryl iodide, palladium, and norbornene, the latter behaving as a second catalyst that is first incorporated into the metallacycle and expelled at the end of the process. Selective alkylation or arylation of the arene nucleus occurring by oxidative addition/reductive elimination of palladacycles are coupled, after norbornene expulsion, with C­H or C­C bond-forming reactions such as hydrogenolysis, olefin insertion, arylboronic coupling, etc. The variety of possible combinations offers a powerful tool for the selective synthesis of unusual and not readily accessible aromatics.
Recent studies on asymmetric hydrogenation. New catalysts and synthetic applications in organic synthesis
Authors: Genet Jean Pierre 
Published: October 2007

Abstract
CODRu(h3methylallyl)2 is a versatile starting material for the preparation of a wide range of chiral bisphosphines ruthenium(II) complexes: (P*P)Ru(h3methylallyl)2 2, Ru[X4(P*P)2] 3, and cationic monohydride ruthenium complex 4. A facile synthesis of new C2 electron-rich chiral phosphines, bis(phosphetano)benzene 8 and 1,1¢bis(phosphetano)ferrocene 10 is presented. Dynamic kinetic resolution was used for efficient syntheses of key components of the hexahydroazepane core 16 of balanol and of optically pure Boc-(2S,3R,3S)-iso-dolaproïne 19. Catalyst 4 was used in asymmetric hydrogenation of 22 to give (+)-cis-methyl dihydrojasmonate in high enantioselectivity.
Oxidative polycyclizations with rhenium(VII) oxides
Authors: Keinan Ehud , Sinha Subhash C. 
Published: October 2007

Abstract
The consecutive oxidative polycyclization reaction with rhenium(VII) oxides represents a highly stereoselective synthetic tool by which polyenes that contain a bis-homoallylic alcohol can be transformed into poly-THF products in a single step. On the basis of a detailed study with model substrates, a set of rules is proposed to predict product configurations in the polycyclization reactions with trifluoroacetylperrhenate. This methodology is exceptionally useful for the synthesis of polyoxygenated carbon skeletons that contain many stereogenic centers, and for the Annonaceous acetogenins in particular. Many of these potent antitumor agents, including solamin, reticulatacin, asimicin, bullatacin, trilobin, trilobacin, squamotacin, rolliniastatin, uvaricin, rollidecins C and D, mucocin, goniocin, and cyclogoniodenin T, as well as chemical libraries of non-natural analogs, were synthesized using the oxidative polycyclization reaction in combination with the Sharpless AD and AE reactions.
Toward the understanding of the mechanism and enantioselectivity of the Pauson­Khand reaction. Theoretical and experimental studies
Authors: Pericàs Miquel A. , Balsells Jaume , Castro Jaume , Marchueta Iolanda , Moyano Albert , Riera Antoni , Vázquez Jordi , Verdaguer Xavier 
Published: October 2007

Abstract
Semiempirical and density functional theory (DFT) calculations have been performed on the key steps of the commonly accepted mechanism of the Pauson­Khand reaction (PKR). In this context, the high reactivity of ynamine complexes in the cycloaddition process has been rationalized on the basis of an anomerically assisted dissociation of CO. Moreover, an explanation has been provided for the correlation between olefin strain and reactivity in the PKR. Inspired by these results, new selective syntheses of cyclopentanones and phenols based on PKR with cyclopropene have been developed. On the other hand, the theoretical analysis of phosphine-substituted dicobalt carbonyl complexes of alkynes has helped in the development of efficient chelating (P,N) and bridging (P,S) ligands for the stereochemical control of the reaction and in the understanding of their action modes.
Addition reactions of heteroatom-COX (X = OR, NR2, COOR) species with alkynes
Authors: Tanaka Masato , Hua Ruimao 
Published: October 2007

Abstract
Heteroatom-COX species where the heteroatom is Cl, S, or Sn and X is alkoxy, amino, or alkoxycarbonyl group were found to add to the triple bond of alkynes regio- and stereoselectively in the presence of Rh, Pd, or Ni catalyst. Scope and limitation of these synthetic reactions were disclosed. Mechanistic study revealed that oxidative addition of these heteroatom-COX bonds readily took place and the resulting adducts were isolable and characterized by X-ray diffraction analysis. Synthetic applications of the catalytic reactions were also demonstrated.
Energy transfers by long-lived species in glows and afterglows
Authors: De Benedictis Santolo , Dilecce Giorgio 
Published: October 2007

Abstract
An overview of the current literature on diagnostics and modeling of energy transfers by long-lived species in N2­CO, He­NO, He­N2­O2, N2­O2, and N2­H2O plasma is given. Energy transfers by vibrationally excited ground-state long-lived species and by electronic molecular and atomic metastables will be highlighted.
New approaches in thermal plasma technology
Authors: Heberlein Joachim 
Published: October 2007

Abstract
Thermal plasmas offer unique advantages for materials processing, such as high fluxes of heat and of reactant species. Recent developments have concentrated on improving control of these fluxes across the boundaries surrounding the thermal plasma. Secondary discharges (hybrid plasma generators) and pulse modulation of the plasma have been some of the approaches for this end. The use of such methods is described for selected applications. Plasma characterization through advanced models and diagnostics are concentrating on description of plasma instabilities and various nonequilibrium conditions. Understanding of these effects will allow their use for enhanced processing methods.
Nonequilibrium discharges in air and nitrogen plasmas at atmospheric pressure
Authors: Kruger Charles H. , Laux Christophe O. , Yu Lan , Packan Denis M. , Pierrot Laurent 
Published: October 2007

Abstract
Diffuse glow discharges were produced in low temperature (<2000 K) atmospheric pressure air and nitrogen plasmas with electron number densities in excess of 1012 cm­3, more than six orders of magnitude higher than in thermally heated air at 2000 K. The measured discharge characteristics compare well with the predictions of a two-temperature kinetic model. Experimental and modeling results show that the steady-state electron number density exhibits an S-shaped dependence on the electron temperature, a behavior resulting from competition between ionization and charge-transfer reactions. Non-Maxwellian effects are shown to be unimportant for the prediction of steady-state electron number densities. The power requirements of DC discharges at atmospheric pressure can be reduced by several orders of magnitude using short repetitive high-voltage pulses. Between consecutive pulses, the plasma is sustained by the finite rate of electron recombination. Repetitive discharges with a 100-kHz, 12-kV, 10-ns pulse generator were demonstrated to produce over 1012 electrons/cm3 with an average power of 12 W/cm3, 250 times smaller than a DC discharge at 1012 cm­3.
Plasma sterilization. Methods and mechanisms
Authors: Moisan Michel , Barbeau Jean , Crevier Marie-Charlotte , Pelletier Jacques , Philip Nicolas , Saoudi Bachir 
Published: October 2007

Abstract
Utilizing a plasma to achieve sterilization is a possible alternative to conventional sterilization means as far as sterilization of heat-sensitive materials and innocuity of sterilizing agents are concerned. A major issue of plasma sterilization is the respective roles of ultraviolet (UV) photons and reactive species such as atomic and molecular radicals. At reduced gas pressure (£10 torr) and in mixtures containing oxygen, the UV photons dominate the inactivation process, with a significant contribution of oxygen atoms as an erosion agent. Actually, as erosion of the spore progresses, the number of UV photons successfully interacting with the genetic material increases. The different physicochemical processes at play during plasma sterilization are identified and analyzed, based on the specific characteristics of the spore survival curves.
Plasma production of nanocrystalline silicon particles and polymorphous silicon thin films for large-area electronic devices
Authors: i Cabarrocas Pere Roca , i Morral Anna Fontcuberta , Lebib Sarra , Poissant Yves 
Published: October 2007

Abstract
Powder formation in silane plasmas has been considered as a technology drawback because it might lead to the formation of macroscopic defects in the deposited layers. Here we summarize our recent efforts in controlling the formation of powder precursors, in particular, nanocrystalline silicon particles, aiming at their incorporation in the films. Indeed, the incorporation of clusters and crystallites along with SiHx radicals allows production of polymorphous silicon films with improved structure and transport properties with respect to standard amorphous silicon films.
Diagnostics and insights on PECVD for gas-barrier coatings
Authors: Creatore Mariadriana , Palumbo Fabio , d'Agostino Riccardo 
Published: October 2007

Abstract
In this work, we report on our last results concerning the polyethyleneterephtalate barrier performance optimization as a function of the chemistry of the SiOx coating, deposited by means of hexamethyldisiloxane/oxygen-fed plasmas ignited in an RF capacitively coupled parallel plates reactor. The influence of the gas feed composition and power on the plasma phase/coating chemistry and on the O2 gas transmission rate has been investigated. The plasma phase has been studied by means of Fourier transform infrared absorption (FT-IR) and optical emission spectroscopies (OES), and the results have been coupled to the film chemistry investigated by means of FT-IR spectroscopy. These techniques show excellent potentialities in the correlation of the plasma phase and film chemistries with the barrier properties of the SiOx-coated polymer, especially when a very good barrier level is required.
Ion-induced damage and annealing of silicon. Molecular dynamics simulations
Authors: Humbird David , Graves David B. 
Published: October 2007

Abstract
A study of the interactions of energetic argon ions with silicon surfaces using molecular dynamics simulations is reported. A dynamic balance between ion-induced damage and recrystallization of the surface is detected. By manipulating ion energy, argon ions are able to both create disordered regions near the surface, and recrystallize these disordered regions.
Plasma treatment of textile fibers
Authors: Höcker Hartwig 
Published: October 2007

Abstract
Low-temperature plasma technologyboth glow discharge under reduced pressure as well as barrier discharge under normal pressureare well established in different industrial applications. Since recently, however, the plasma technology is being introduced in textile industry as well. Fields of application are desizing, functionalizing, and design of surface properties of textile fibers. Plasma technology is suitable to modify the chemical structure as well as the topography of the surface of the material.
Examples of natural as well as man-made fibers prove the enormous potential of plasma treatment of textile materials. It has proven to be successful in shrink-resist treatment of wool with a simultaneously positive effect on the dyeing and printing.
Not only the chemical structure of the surface is modified using different plasma gases but also the topography of the surface. A highly hydrophobic surface with a particular surface topography in contact with water is extremely dust- and dirt-repellent and hence should be also repellent to bacteria and fungi.
Man-made fibers to be used under chemical stress are modified with diffusion-barrier layers on their surfaces without modifying the bulk properties; hence, the stability of those fibers is significantly improved.