bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of polyvinylpyrrolidone on the formation of perovskite phase and rosette-like structure in sol-gel–derived PLZT films
Authors: Du Z.H. , Zhang T.S. , Ma J.
Published: August 2007

Poly-vinylpyrrolidones (PVP) with different molecular weights were used to modify the sol-gel solutions for preparing Pb0.91La0.09(Zr0.65,Ti0.35)0.9775O3 (PLZT, 9/65/35) thin films. The crystallization behavior and microstructural development of the PLZT films with and without PVP addition were investigated. It was found that the addition of PVP significantly improved perovskite phase formation of the PLZT films, but the films exhibited rosette-like morphology. Further study on the PLZT films and the gel particles showed that a premature nucleation of PbO grains in the PVP modified sol-gel solution induced the Pb-rich domains in the films, which accelerated the growth of the grains and thus led to the rosette-like structure. In addition, the electrical and optical properties of the PLZT films with rosette-like structure were also studied and discussed.
PbSe nanocrystal/conducting polymer solar cells with an infrared response to 2 micron
Authors: Jiang Xiaomei , Schaller Richard D. , Lee Sergey B. , Pietryga Jeffrey M. , Klimov Victor I. , Zakhidov Anvar A.
Published: August 2007

We investigated the photovoltaic response of nanocomposites made of colloidal, infrared-sensitive, PbSe nanocrystals (NCs) of various sizes and conjugated polymers of either regioregular poly (3-hexylthiophene) (RR-P3HT) or poly- (2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene) (MEH-PPV). The conduction and valence energy levels of PbSe NCs were determined by cyclic voltammetry and revealed type II heterojunction alignment with respect to energy levels in RR-P3HT for smaller NC sizes. Devices composed of NCs and RR-P3HT show good diode characteristics and sizable photovoltaic response in a spectral range from the ultraviolet to the infrared. Using these materials, we have observed photovoltaic response at wavelengths as far to the infrared as 2 μm (0.6 eV), which is desirable due to potential benefits of carrier multiplication (or multi-exciton generation) from a single junction photovoltaic. Under reverse bias, the devices also exhibit good photodiode responses over the same spectral region.
Dielectric abnormity of Sr4Nd2Ti4Nb6O30 tungsten bronze ceramics over a broad temperature range
Authors: Zhu X.L. , Chen X.M. , Liu X.Q.
Published: August 2007

In the present paper, Sr4Nd2Ti4Nb6O30 ceramics with filled tungsten bronze structure were prepared, and the dielectric characteristics over a broad temperature range (123 to 623 K) were investigated. Two dielectric abnormities were observed in the entire frequency range (100 Hz to 1 MHz). One is at higher temperature corresponding to a diffuse ferroelectric transition (P4/mbm → P4bm), and the other at lower temperature shows relaxor characteristics in both ϵ′ and tan δ curves. An activation energy and freezing temperature of 0.1659 eV and 148.05 K, respectively, were obtained by analyzing the frequency dependence of the dielectric maximum temperature using the Vogel–Fulcher relationship. The relaxor behavior is attributed to a polar-glassy system with thermally activated polarization fluctuations above the freezing temperature. In addition, the dielectric constant was almost stable with both temperature and frequency in the temperature range of 300 to 430 K (between the two dielectric abnormities).
Dynamics of a Recovering Lake Trout Population in Eastern Wisconsin Waters of Lake Superior, 1980–2001
Authors: Linton Brian C. , Hansen Michael J. , Schram Stephen T. , Sitar Shawn P.
Published: August 2007

Lake trout Salvelinus namaycush are important in Lake Superior because of their economic and ecological value. Lake trout populations collapsed in the early 1950s due to overexploitation by the commercial fishery and predation by sea lampreys Petromyzon marinus. Efforts to rehabilitate a self-sustaining lake trout population included stocking of hatchery-reared lake trout, control of sea lamprey populations, and closure of the lake trout fishery. To quantify and describe the dynamics of the recovering lake trout population in eastern Wisconsin waters of Lake Superior between 1980 and 2001, we used statistical catch-at-age analysis to estimate abundance, recruitment, mortality, and fishery selectivity of wild and stocked lake trout. We found that estimated wild lake trout abundance increased, whereas estimated stocked lake trout abundance decreased. Estimated wild lake trout recruitment was erratic, while estimated stocked lake trout recruitment decreased until stocking was discontinued in 1996. Natural mortality was the largest component of estimated wild lake trout total mortality, where commercial fishing mortality was the largest component of estimated stocked lake trout total mortality. Wild lake trout abundance in Wisconsin waters of Lake Superior is on par with precollapse abundance levels, and total mortality rates are below rehabilitation target levels; however, wild lake trout recruitment is still below the level thought necessary to sustain the population.
Comparisons of FST and QST of Growth‐Related Traits in Two Populations of Coho Salmon
Authors: McClelland Erin K. , Naish Kerry A.
Published: August 2007

Understanding the mechanisms driving population divergence may be an important step in achieving conservation goals. Estimates of population divergence at neutral markers (FST) can be compared with divergence at quantitative traits (QST) to determine whether population differentiation is being driven by neutral processes such as genetic drift or by selection. We examined growth‐related fitness traits, specifically length, weight, and condition factor, at various life history stages in coho salmon Oncorhynchus kisutch. Fish from two populations originating in different evolutionarily significant units and with different histories of selection were reared in a common environment, and weight and length measurements were collected for the alevin and juvenile stages during the first year of growth. Divergence at neutral markers was estimated from 10 microsatellite loci typed in each of the two populations (FST = 0.089, 95% confidence interval = 0.056‐0.0123). While QST tended to be greater than FST across all sample dates, this relationship was only significant when juvenile traits were combined for all sample dates (QST = 0.406, 95% confidence interval = 0.305‐0.468). These results suggest that diversifying selection is driving the differentiation between the two populations examined for the juvenile growth traits measured.
Delays in Cancer Diagnosis in Underinsured Young Adults and Older Adolescents
Authors: Martin Sean , Ulrich Corinne , Munsell Mark , Taylor Sarah , Lange Georgia , Bleyer Archie
Published: August 2007

Learning Objectives

After completing this course the reader will be able to: Describe the relative lack of progress in survival improvement in young adults and older adolescents with cancer.Explain the variability in the time to diagnosis of cancer among young adults and older adolescents.Identify the potential role of health insurance in determining the time to cancer diagnosis in young adults and older adolescents.Discuss the impact that universal health insurance may have in shortening the time to cancer diagnosis and treatment in young adults and older adolescents.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Presurgical Chemotherapy in Patients Being Considered for Liver Resection
Authors: Kemeny Nancy
Published: August 2007

Learning Objectives

Describe the approach to patients with unresectable liver metastases from colorectal cancer. Identify the hepatotoxicities associated with chemotherapy. Explain what happens to metastatic sites when there is a response.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Nonaqueous‐Phase Liquid Infiltration and Immobilization in Heterogeneous Media: 1. Experimental Methods and Two‐Layered Reference Case
Authors: Fagerlund F. , Illangasekare T.H. , Niemi A.
Published: August 2007

Accurate data to understand the migration and entrapment of nonaqueous‐phase liquids (NAPLs) in heterogeneous formations are presently lacking. A series of well‐controlled laboratory experiments were conducted to investigate the infiltration and subsequent immobilization of dense NAPLs in saturated heterogeneous media. The focus of this first study was the development of a special experimental methodology for measuring the dynamic evolution of a NAPL plume in space and time. To demonstrate the method, a reference case of a two‐layered formation consisting of two homogeneous sands separated by a dipping interface is presented. The dipping formation in the reference case allows the study of NAPL behavior at texture interfaces under the influence of both capillary and gravitational forces. The NAPL‐saturation measurement methodology, based on a multiple‐energy x‐ray attenuation technique, correctly captured the known injected NAPL volume as well as the general spreading and entrapment behavior in space and time. Time‐continuous measurements of NAPL saturations allow the study of the history dependence of entrapped saturations. The Land model predicted the observed trend in the entrapment behavior well. The entrapment architecture was parameterized using spatial moments and moments of mass distribution at different saturations. The general features of the NAPL architecture were successfully characterized by a simultaneous interpretation of these moments, while the domination of discontinuous or continuous NAPL was captured by the ganglia/pool ratio.
Situating the New 527 Organizations in Interest Group Theory
Authors: Boatright Robert G
Published: August 2007

This article seeks to reconcile the activities of several of the groups organized during the 2004 election cycle under section 527 of the Internal Revenue Code with existing theories of party and interest group behavior. While 527 groups have frequently been categorized as extensions of traditional advocacy groups or party networks, I argue that existing theories do not account for the functional differentiation between these groups. This functional differentiation marks a relatively unprecedented development in American interest group politics. However, the highly partisan nature of the 2004 election and the limited appeal of these groups either to party donors or to a broad base of interest groups may indicate that such groups will not endure or play as prominent a role in 2008 as they did in 2004 even absent changes in FEC rules.
Turning Up the Heat on Global Environmental Governance
Authors: Haas Peter M
Published: August 2007

This piece reviews alternative reform proposals for international environmental governance, and the role of the United Nations Environment Program (UNEP) in a new international environmental architecture. It argues for streamlining UNEP as a scientific hub within a broader international network of linked actors involved in environmental governance.
Agitation Effects in a Gas-Liquid-Liquid Reactor System: Methyl Ethyl Ketazine Production
Authors: Kaur Raminder , Machiraju Ramakrishna , Nigam K.D.P.
Published: August 2007

Our understanding of gas-liquidliquid reaction systems is not well developed today despite their widespread use in the process industries. Research work is demanded or inspired in those fields where basic information is either lacking or poorly organized. The field of mixing and agitation in gas-liquid-liquid reaction system is a typical example. Methyl ethyl ketazine formation is a typical case of homogeneous catalyzed gas-liquid-liquid reaction. The parametric study of ketazine formation has been carried out in a semi batch reactor. Agitation effect on methyl ethyl ketazine formation has been studied. Two types of agitators are used - flat paddle stirrer and vaned disk stirrer. The studies show that agitation plays an important role on the reaction. Yield of ketazine improved with degree of agitation, categorizing the reaction as moderately fast. Vaned disk stirrer is found to be more effective compared to flat paddle stirrer. Rate of reaction increases up to 600 rpm indicating diffusion control, beyond 600 rpm there is no appreciable change in the yield, thus favoring kinetics controlled mechanism. This 600 rpm can be thus regarded as "the desired level of agitation."
Molecular Simulation Study of Vapor-Liquid Equilibrium of Morse Fluids
Authors: Kwak Sang Kyu , Singh Jayant K , Adhikari Jhumpa
Published: August 2007

The Morse potential energy function (PEF) is considered regarding the characterization of interaction forces of particles with tuning parameters. Phase coexistence of Morse fluids is predicted for different steepness and range of the PEF parameters using the grand-canonical transition matrix Monte Carlo (GC-TMMC) method, with quantification of the parameter S, which is the product of a constant with a unit of reciprocal length and the equilibrium distance between two molecules. We found that a lower limit of S exists bounded by infinite critical temperature. The critical properties of the vapor-liquid equilibrium curves are estimated using a rectilinear diameter method and a scaling law approach. A Clausius-Clayperon type relation of S and critical temperature is derived in this work. Vapor-liquid surface tension of Morse fluids by finite size scaling and GC-TMMC is also reported. Surface tensions are found to be higher at lower S.
Determination of potassium in fatty acid methyl esters applying an ion-selective potassium electrode
Authors: Rapta P. , Paligová J. , Rotheneder H. , Cvengroš J.
Published: August 2007

An easy and inexpensive method of potassium determination in fatty acid methyl esters (FAME) applying an ion-selective potassium electrode (ISE-K) is presented. FAME are considered alternative fuel for diesel engines. Simple apparatus and procedure were developed to avoid contact of ester samples with the sensitive ISE-K membrane, which can damage the ISE membrane surface in long time operation. Using different FAME samples with a wide range of known potassium content a calibration curve was constructed. Among all samples, ISE-K satisfactory predicted potassium content in FAME as identified by the AAS reference method.
Properties of fructosyltransferase from Aureobasidium pullulans immobilized on an acrylic carrier
Authors: Onderková Z. , Bryjak J. , Polakovič M.
Published: August 2007

Optimization of immobilization conditions was carried out for covalent binding of Aureobasidium pullulans fructosyltransferase to a copolymer of butyl acrylate and ethylene glycol dimethacrylate using a glutaraldehyde method. It was found that the highest activity of the preparation could be obtained for the immobilization pH 6.0 and initial protein amount 8.5 g per dm3 of the carrier. Effects of the reaction pH, temperature, and initial sucrose concentration on the activity and stability of the preparation were analyzed. Further investigations involved storage stability and operational stability in a mechanically stirred-tank reactor.
A detailed analysis of volatile constituents of Aquilegia pancicii Degen, a Serbian steno-endemic species
Authors: Radulović N. , Dekić M. , Zlatković B. , Dekić S. , Dekić V. , Palić R.
Published: August 2007

Chemical composition of the essential oil of Aquilegia pancicii Degen endemic to Serbia is reported. Essential oil obtained by hydrodistillation from the aerial parts was analyzed by GC and GC/MS. The major constituents were hexadecanoic acid (24.3 %) and hexahydrofarnesyl acetone (14.1 %), among 130 identified compounds, representing 90.3 % of the total essential oil. The oil was marked by the presence of 69 fatty acid derivatives and low content of terpenoids representing 60.4 % and 7.8 % of the oil, respectively.
Functionalization of Cubic Ia3d Mesoporous Silica for Immobilization of Penicillin G Acylase
Authors: Lü Y. , Lu G. , Wang Y. , Guo Y. , Guo Y. , Zhang Z. , Wang Y. , Liu X.
Published: August 2007

Functionalized cubic Ia3d mesoporous silica (FCIMS) with glycidoxypropyl groups was prepared and characterized by powder XRD, N2 adsorption, TGA, FT‐IR spectroscopy, solid state 13C NMR spectroscopy and TEM, and studied as the support for the immobilization of Penicillin G acylase (PGA). The results show that the glycidoxypropyl groups have been chemically bonded to the silicon atoms on the surface of cubic Ia3d mesoporous silica (CIMS). The FCIMS materials possess the mesoporous structure with pore diameter of 8 nm which is ∼ 1 nm less than that of CIMS (9 nm). The influence of the amount of glycidoxypropyl groups on the initial specific activity and operational stability of PGA immobilized on FCIMS were examined for the hydrolysis of penicillin G potassium salt. The results show that PGA has been successfully immobilized covalently on the FCIMS materials, and the initial specific activity of PGA/FCIMS is 835 IU g–1 and PGA/CIMS is 624 IU g–1. After repeated use for 10 times, PGA/FCIMS retains 72 % of its initial specific activity and PGA/CIMS retains only 58 %.
Self‐Assembled Nanoparticles Based Fabrication of Gecko Foot‐Hair‐Inspired Polymer Nanofibers
Authors: Kustandi T. S. , Samper V. D. , Yi D. K. , Ng W. S. , Neuzil P. , Sun W.
Published: August 2007

Wafer‐scale polymer nanofabrillar structures have been fabricated using the combination of colloidal nanolithography, deep‐silicon etching, and nanomolding to mimic the nanostructure of gecko foot‐hairs. The artificial surface features densely packed polymeric nanofibrils with super‐hydrophobic, water‐repellent, and “easy‐to‐clean” characteristics. The lateral dimension of the nanofibrils is as small as 250 nm and an aspect‐ratio as high as 10:1 has been achieved without lateral collapse between neighboring fibrils. The method allows both fabrication of synthetic structures over a large area and direct integration of a flexible membrane to assist the array of nanofibrils in making intimate contact with uneven surfaces. A single nanofibril exhibits a mean adhesive force ranging from (0.91 ± 0.34) nN to (1.35 ± 0.37) nN. In the macroscopic scale, the nanostructured surface can adhere firmly to a smooth glass substrate and inherits the in‐use, self‐cleaning property of the setal nanostructures found in gecko lamellae.
Shape Control of Platinum Nanoparticles
Authors: Ramirez E. , Eradès L. , Philippot K. , Lecante P. , Chaudret B.
Published: August 2007

The synthesis of shape controlled platinum nanoparticles has been investigated through an organometallic approach starting from the complex Pt2(dba)3 and using a long alkyl chain amine, hexadecylamine (HDA), as stabilizer. The influence of the experimental parameters (reactive gas and solvent nature, stabilizer/metal ratio, reactants concentration, temperature) on the shape of the Pt nanoparticles has been studied. Various shaped platinum nanostructures such as isolated nanoparticles, dendrites or crystalline nanowires were obtained, depending on the reaction conditions. This method takes profit of the mild conditions of chemistry in solution and allows obtaining regular nanostructures, most of them being homogeneous in shape as well as in size (isolated nanoparticles) or diameter/length (nanowires). Transmission electron microscopy and wide‐angle X‐ray scattering were used as characterization techniques. Beside the Knight‐shift effect of platinum, NMR solution investigations clearly evidenced the coordination of the amine at the Pt particles surface and its mobility. This mobility, increased when H2 is used as reactive gas for the precursor decomposition, favors the particles coalescence into nanowires. This phenomenon is also favored by the “soft” template character of the amine in particular in toluene solution.
Synthesis of Inorganic and Organic–Inorganic Hybrid Hollow Particles Using a Cationic Surfactant with a Partially Fluorinated Tail
Authors: Tan B. , Vyas S. M. , Lehmler H.‐J. , Knutson B. L. , Rankin S. E.
Published: August 2007

A new partially fluorinated cationic surfactant, 1‐(10‐perfluorooctyldecyl)pyridinium bromide monohydrate, is synthesized and used as the template for mesoporous ceramic and inorganic–organic hybrid particles. Several hydrolyzed alkoxide precursors are shown to co‐assemble with this surfactant to form hollow vesicle‐like particles, and the effect of changing the alkoxide chemical structure on the formation of these particles is examined. Tetramethoxysilane produces cubic or columnar particles without hollow cavities, but all other tetra‐n‐alkoxysilanes tested up to the n‐butoxide produce hollow particles. As the alkoxide length increases, the shell structure changes from multilayered (with Si(OC2H5)4) to a single thin layer (with Si(OC3H7)4) to a single thick layer (with Si(OC4H9)4). The stability of the fluorocarbon bilayers allows similar vesicular structures to be obtained in organic–inorganic hybrids prepared with bridged alkoxysilanes. Ethylene‐bridged silanes display similar structures to tetraalkoxysilanes. However, the hollow structures appear to partially collapse when the bridging chain is too long (octylene) and no hollow particles are formed with bis(trialkoxysilylpropyl)amines.
Preparation of Multicomponent Metal Oxides Using Nozzle Spray and Microwaves
Authors: Espinal L. , Malinger K. A. , Espinal A. E. , Gaffney A. M. , Suib S. L.
Published: August 2007

Multicomponent metal oxide (MMO) crystallites are prepared by spraying a reactant solution into a receiving solution or into air under microwave radiation at atmospheric pressure. The injection of a nitric acid solution through an ultrasonic nozzle into a receiving solution of metal precursor and the use of microwave radiation are combined to form a novel preparation technique called the nozzle‐spray/microwave (NMW) method. The inclusion of an additional step, the in situ mixing of precursor solutions prior to their injection through the ultrasonic nozzle spray, leads to another procedure called the in situ/nozzle‐spray/microwave (INM) method. For comparison, MMO materials with the same metal constituents as those prepared by our novel techniques are prepared by conventional hydrothermal (CH) methods. Fresh materials prepared by NMW, INM, and CH methods were heat treated to study the effect of calcination. All materials were characterized before and after calcination using X‐ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller surface area, and inductively coupled plasma elemental analysis. The NMW method produces particles with rodlike morphologies different from those obtained using CH methods. The INM method produces an amorphous material that crystallizes after calcination into small (ca. 200 nm) particles with interesting morphologies. Notably, calcination of materials prepared by both NMW and INM reduces the particle size and increases the surface area. The work presented in this paper paves the way to use NMW and INM to prepare MMOs with unique morphologies.
Versatile Supramolecular Nanovalves Reconfigured for Light Activation
Authors: Nguyen T. D. , Leung K. C.‐F. , Liong M. , Liu Y. , Stoddart J. F. , Zink J. I.
Published: August 2007

All autonomous machines share the same requirement—namely, they need some form of energy to perform their operations and nanovalves are no exception. Supramolecular nanovalves constructed from [2]pseudorotaxanes—behaving as dissociatable complexes attached to mesoporous silica which acts as a supporting platform and reservoir—rely on donor‐acceptor and hydrogen bonding interactions between the ring component and the linear component to control the ON and OFF states. The method of operation of these supramolecular nanovalves involves primarily the weakening of these interactions. The [2]pseudorotaxane [BHEEEN ⊂ CBPQT]4+ [BHEEEN ≡ 1,5‐bis[2‐(2‐(2‐hydroxyethoxy)ethoxy)ethoxy]naphthalene and CBPQT4+ ≡ cyclobis(paraquat‐p‐phenylene)], when this 1:1 complex is tethered on the surface of the mesoporous silica, constitutes the supramolecular nanovalves. The mesoporous silica is charged against a concentration gradient with luminescence probe molecules, e.g., tris(2,2′‐phenylpyridyl)iridium(III), Ir(ppy)3 (ppy = 2,2′‐phenylpyridyl), followed by addition of CBPQT·4Cl to form the tethered [2]pseudorotaxanes. This situation corresponds to the OFF state of the supramolecular nanovalves. Their ON state can be initiated by reducing the CBPQT4+ ring with NaCNBH3, thus weakening the complexation and causing dissociation of the CBPQT4+ ring away from the BHEEEN stalks on the mesoporous silica particles MCM‐41 to bring about ultimately the controlled release of the luminescence probe molecules from the mesoporous silica particles with an average diameter of 600 nm. This kind of functioning supramolecular system can be reconfigured further with built‐in photosensitizers, such as tethered 9‐anthracenecarboxylic acid and tethered [Ru(bpy)2(bpy(CH2OH)2)]2+ (bpy = 2,2′‐bipyridine). Upon irradiation with laser light of an appropriate wavelength, the excited photosensitizers transfer electrons to the near‐by CBPQT4+ rings, reducing them so that they dissociate away from the BHEEEN stalks on the surface of the mesoporous silica particles, leading subsequently to a controlled release of the luminescent probe molecules. This control can be expressed in both a regional and temporal manner by the use of light as the ON/OFF stimulus for the supramolecular nanovalves.
Engineering of Self‐Assembled Domain Architectures with Ultra‐high Piezoelectric Response in Epitaxial Ferroelectric Films
Authors: Ouyang J. , Slusker J. , Levin I. , Kim D.‐M. , Eom C.‐B. , Ramesh R. , Roytburd A. L.
Published: August 2007

Substrate clamping and inter‐domain pinning limit movement of non‐180° domain walls in ferroelectric epitaxial films thereby reducing the resulting piezoelectric response of ferroelectric layers. Our theoretical calculations and experimental studies of the epitaxial PbZrxTi1–xO3films grown on single crystal SrTiO3demonstrate that for film compositions near the morphotropic phase boundary it is possible to obtain mobile two‐domain architectures by selecting the appropriate substrate orientation. Transmission electron microscopy, X‐ray diffraction analysis, and piezoelectric force microscopy revealed that the PbZr0.52Ti0.48O3films grown on (101) SrTiO3substrates feature self‐assembled two‐domain structures, consisting of two tetragonal domain variants. For these films, the low‐field piezoelectric coefficient measured in the direction normal to the film surface (d33) is 200 pm V–1, which agrees well with the theoretical predictions. Under externalACelectric fields of about 30 kV cm–1, the (101) films exhibit reversible longitudinal strains as high as 0.35 %, which correspond to the effective piezoelectric coefficients in the order of 1000 pm V–1and can be explained by elastic softening of the PbZrxTi1–xO3ferroelectrics near the morphotropic phase boundary.
Mechanical Properties of Robust Ultrathin Silk Fibroin Films
Authors: Jiang C. , Wang X. , Gunawidjaja R. , Lin Y.‐H. , Gupta M. K. , Kaplan D. L. , Naik R. R. , Tsukruk V. V.
Published: August 2007

Robust ultrathin multilayer films of silk fibroin were fabricated by spin coating and spin‐assisted layer‐by‐layer assembly and their mechanical properties were studied both in tensile and compression modes for the first time. The ultrathin films were characterized by a high elastic modulus of 6–8 GPa (after treatment with methanol) with the ultimate tensile strength reaching 100 MPa. The superior toughness is also many times higher than that usually observed for conventional polymer composites (328 kJ m–3 for the silk material studied here versus typical values of < 100 kJ m–3). These outstanding properties are suggested to be caused by the gradual development of the self‐reinforcing microstructure of highly crystalline β‐sheets, serving as reinforcing fillers and physical crosslinks, a process that is well known for bulk silk materials but it is demonstrated here to occur in ultrathin films as well, despite their limited dimensions. However, the confined state within films thinner than the lengths of the extended domains causes a significantly reduced elasticity which should be considered in the design of nanosized films from silk materials. Such regenerated silk fibroin films with outstanding mechanical strength have potential applications in microscale biodevices, biocompatible implants, and synthetic coatings for artificial skin.
Warfarin reversal emerging as the major indication for fresh frozen plasma use at a tertiary care hospital
Authors: Ozgonenel Bulent , O'Malley Barbara , Krishen Priya , Eisenbrey A.B.
Published: August 2007

Because of the increase in the use of warfarin in the population in recent years, reversal of warfarin‐related coagulopathy has become common in daily hospital practice. Transfusion of fresh frozen plasma (FFP) is the preferred treatment method for urgent warfarin reversal in the USA. We have undertaken a 1‐month audit of FFP usage to ascertain the impact of warfarin use on the consumption of FFP. Sixty percent of the 376 units of FFP that were transfused during the study month were used to reverse warfarin effects. The most common reason to reverse warfarin was bleeding. Thirty‐three percent of the units were used for the treatment of other coagulopathies, 7% were used in therapeutic plasmapheresis, and <1% was transfused empirically. One hundred and eighteen patients received FFP during the study month. The study population consisted mostly of elderly patients (65%); however, the warfarin reversing patients consisted disproportionately more of elderly patients (75%) compared with patients receiving FFP for other reasons (46%) (P = 0.0032). Warfarin reversal emerged as the major indication for FFP use in this study. Blood banks of hospitals serving a predominantly elderly patient population should anticipate a higher consumption of FFP. Careful monitoring of warfarin therapy, stringent implementation of the warfarin reversal guidelines, and the introduction of newer products for warfarin reversal would help reduce the consumption of FFP. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Influence of TESPT content on crosslink types and rheological behaviors of natural rubber compounds reinforced with silica
Authors: Choi Sung‐Seen , Kim Ik‐Sik , Woo Chang‐Su
Published: August 2007

Rheological behaviors in the rheographs and crosslink types of silica‐filled natural rubber compounds with differing contents of silane coupling agent were investigated. Bis‐(3‐(triethoxysilyl)‐propyl)‐tetrasulfide (TESPT) was used as a silane coupling agent. In the rheographs of the silica‐filled compounds containing TESPT, the local minimum torque regions after the maximum torque were observed, and the time to reach the local minimum torque was found to become faster with increase of the TESPT content. The reversion ratio, on the whole, was decreased by increasing the TESPT content. By increasing the TESPT content, the crosslink densities of the mono‐, di‐, and polysulfides were increased. Ratio of the polysulfides of the total crosslink density increased, while those of the mono‐ and disulfides decreased with increase of the TESPT content. Changes of the crosslink densities after thermal aging were also investigated. The experimental results were explained with the reduction of curatives adsorbed on the silica, increase of sulfur content, and crosslink formation between the silica and rubber by adding TESPT. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Porous structure and liquid‐phase adsorption properties of activated carbon aerogels
Authors: Yang Wenjin , Wu Dingcai , Fu Ruowen
Published: August 2007

In this article, activated carbon aerogels (ACAs) were prepared by CO2 activation. Their pore structures were investigated by N2 adsorption–desorption analysis. ACAs have excellent microporosity (e.g. 0.36 cm3/g) and mesoporosity (e.g. 1.72 cm3/g). Adsorption characteristics of phenol, methylene blue, I2, and VB12 on ACAs in the liquid phase were studied by static adsorption experiments. Results showed that CO2 activation process is an effective way to introduce micropores in carbon aerogels, which is enhanced with the increase of activation time. As a result, the adsorption capacities of the four mentioned adsorbates on ACAs were improved gradually with the increase of activation time. However, mesopore volume is also a factor on improving adsorption properties for the relatively giant molecules methylene blue and VB12. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
A new technique for foaming submicron size poly(methyl methacrylate) particles
Authors: Ogawa Hiroyuki , Ito Akihiro , Taki Kentaro , Ohshima Masahiro
Published: August 2007

About 0.7–2 μm diameter poly (methyl methacrylate) (PMMA) foamed particles were prepared via thermally induced phase separation (TIPS) from a PMMA/ethanol mixture and vacuum dried. It was found that ethanol, known to be a poor solvent to PMMA, could dissolve PMMA when the temperature was over 60°C. The solubility of PMMA (Mw = 15,000 and Mw = 120,000) in ethanol was measured and was found to increase as the temperature increased. PMMA particles on the scale of submicron and single micron diameter could be precipitated from the PMMA/ethanol solution by temperature quenching. Then, since the precipitated particles contained a certain amount of ethanol, the precipitated particles could be foamed using the ethanol as a foaming agent in a vacuum drying process. Vacuum drying at temperatures slightly below the glass transition temperature of the polymer could make the particles foam. The effects of foaming temperature and the molecular weight of the polymer on the size of foamed particles were investigated. The experimental results showed that the vapor pressure and the molecular weight of the polymer are key factors determining the expandability of the micro particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Impact of anastomotic leakage on oncological outcome after rectal cancer resection
Authors: Ptok H , Marusch F , Meyer F , Schubert D , Gastinger I , Lippert H
Published: August 2007

Background

Anastomotic leakage has a major impact on morbidity and mortality in rectal cancer surgery. Its relevance to oncological outcome is controversial. This observational study investigated the influence of anastomotic leakage on oncological outcome.

Methods

Data for 1741 patients undergoing curative resection of rectal cancer (located less than 12 cm from the anal verge) with normal healing were compared with those for 303 patients who experienced anastomotic leakage. Morbidity, mortality and long-term oncological outcomes were analysed.

Results

Median follow-up was 40 months. Patients with anastomotic leakage had a higher postoperative mortality rate than those with no leakage (4·3 versus 1·2 per cent; P < 0·001). Patients with leakage necessitating surgical treatment had a higher 5-year local recurrence rate (17·5 versus 10·1 per cent; P = 0·006) and a lower 5-year disease-free survival rate (70·9 versus 75·4 per cent; P = 0·020) than those without leakage. Patients with anastomotic leakage not requiring surgical intervention did not have a worse oncological outcome.

Conclusion

A negative prognostic impact of anastomotic leakage on local recurrence and disease-free survival was found only for patients with leakage needing surgical revision.
Laparoscopic approach in surgical treatment of rectal cancer
Authors: Laurent C , Leblanc F , Gineste C , Saric J , Rullier E
Published: August 2007

Background

High rates of conversion to open operation and morbidity have been reported after laparoscopic total mesorectal excision (TME) with sphincter preservation for rectal cancer. This study examined risk factors for conversion and morbidity to determine which patients with rectal cancer could benefit from a laparoscopic resection.

Methods

Two hundred patients (117 men) with mid and low rectal cancer treated by laparoscopic TME were studied. The impact of clinical and pathological characteristics on conversion and complications was assessed by multivariable analysis.

Results

Reconstruction after TME included 79 low colorectal and 121 coloanal anastomoses. Conversion was necessary in 31 patients (15·5 per cent), and was independently associated with sex, type of anastomosis and intraoperative rectal fixity. Postoperative morbidity in 50 patients (25·0 per cent) was independently associated with sex and type of anastomosis. Men with a stapled anastomosis had a threefold higher rate of conversion (13 (34 per cent) of 38 versus 18 (11·1 per cent) of 162; P < 0·001) and morbidity (22 (58 per cent) versus 28 (17·3 per cent); P < 0·001) than other patients.

Conclusion

Laparoscopic TME is a good option for women and for men treated by coloanal anastomosis. Technical improvement of laparoscopic stapling is needed before the laparoscopic approach can be offered to all patients.
Bond Paths as Privileged Exchange Channels
Authors: Pendás A. Martín , Francisco Evelio , Blanco Miguel A. , Gatti Carlo
Published: August 2007

Evidence that the bond paths of the quantum theory of atoms‐in‐molecules (QTAIM) signal preferred quantum‐mechanical exchange channels is presented. We show how bond paths between an atom A and the atoms B in its environment appear to be determined by competition among the A–B exchange‐correlation energies that always contribute to stabilize the A–B interactions. These pairwise additive stabilizations depend neither on the attractive or repulsive nature of the classical electrostatic interaction between the atoms' charge densities, nor on the change in the self energies of the atoms involved. These other terms may well cause an overall molecular‐energy increase in spite of a possibly large A–B exchange‐correlation stabilization. After our proposal, bond paths, both at and out of equilibrium geometries, are endowed with a specific energetic meaning that should contribute to reconcile the orthodox QTAIM interpretation with other widely accepted views, and to settle recent controversies questioning the meaning of hydrogen–hydrogen bonding and the nature of the so‐called “steric interactions”, the role of bond paths in endohedral complexes, and the generality of the results provided by the QTAIM. Implications for the nature of more general closed‐shell interactions are also briefly discussed.
Structure and Stability of VO2+ in Aqueous Solution: A Car—Parrinello and Static ab initio Study.
Authors: Sadoc Aymeric , Messaoudi Sabri , Furet Eric , Gautier Regis , Le Fur Eric , le Polles Laurent , Pivan Jean‐Yves
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Intense Emission of Ca5(PO4)3F:Tb3+ under VUV Excitation and Its Potential Application in PDPs.
Authors: Liang Hongbin , Zeng Qu , Tian Zifeng , Lin Huihong , Su Qiang , Zhang Guobin , Fu Yibing
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Lithium Dimer Formation in the Li‐Conducting Garnets Li5+xBaxLa3‐xTa2O12 (0 < x ≤ 1.6).
Authors: O'Callaghan Michael P. , Cussen Edmund J.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Oxygen Vacancy Ordering Phenomena in the Mixed‐Conducting Hexagonal Perovskite Ba7Y2Mn3Ti2O20.
Authors: Kuang Xiaojun , Allix Mathieu , Ibberson Richard M. , Claridge John B. , Niu Hongjun , Rosseinsky Matthew J.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Study of Transport Properties of the Co1‐xRhxSb3.
Authors: Wojciechowski K. T.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Neutron Diffraction Study on the Magnetic Structure of (Fe0.70Co0.30)2P.
Authors: Jain S. K. , Kumar Sudhish , Krishna P. S. R. , Shinde A. B. , Krishnamurthy Anjali , Srivastava Bipin K.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Interaction of the Components in the Dy—Ag—Sn Ternary System at 870 K.
Authors: Romaka V. V. , Tkachuk A. , Davydov V.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Investigation of the R2Se3—Cu2Se—In2 Se3 (R: La, Pr, Y and Er) Systems at 870 K and Crystal Structure of the R2CuInSe5 (R: La, Ce and Pr) Compounds.
Authors: Huch M. R. , Gulay L. D. , Olekseyuk I. D.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Facile Preparation and Electrochemical Properties of Cubic‐Phase Li4Mn5O12 Nanowires.
Authors: Tian Yang , Chen Dairong , Jiao Xiuling , Duan Yongzheng
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Unprecedented Flexibility of the <Ti=Si< Group for the Addition of H2.
Authors: Maj Lukasz , Grochala Wojciech
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Application of Ferrocenyl‐Substituted Aziridinylmethanols (FAM) as Chiral Ligands in Enantioselective Conjugate Addition of Diethylzinc to Enones.
Authors: Isleyen Alper , Dogan Oezdemir
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Secondary Benzylation with Benzyl Alcohols Catalyzed by a High‐Valent Heterobimetallic Ir—Sn Complex.
Authors: Podder Susmita , Choudhury Joyanta , Roy Sujit
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Aerobic Oxidation of Alcohols under Visible Light Irradiation of Fluorescent Lamp.
Authors: Hirashima Shin‐ichi , Itoh Akichika
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Oxidative Cleavage of 1,2‐Diols, α‐Ketols and 1,2‐Diketones with Aqueous Sodium Hypochlorite.
Authors: Khurana J. M. , Sharma P. , Gogia A. , Kandpal B. M.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Facile and Selective Oxidation of Benzylic Alcohols to Their Corresponding Carbonyl Compounds with Sodium Nitrate in the Presence of Broensted Acidic Ionic Liquids.
Authors: Hajipour Abdol R. , Rafiee F. , Ruoho A. E.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Nitration of Aromatic Compounds Catalyzed by Divanadium‐Substituted Molybdophoshoric Acid, H5[PMo10V2O40].
Authors: Heravi Majid M. , Bakhtiari Khadijeh , Benmorad Tina , Bamoharram Fatemeh F. , Oskooie Hossein A. , Tehrani Maryam H.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Modern Friedel—Crafts Chemistry. Part 27. Alkylation of Benzene with 1‐Benzyl‐ and 1‐Phenylcyclohexanols in the Presence of H2SO4 and AlCl3/CH3NO2 Catalysts.
Authors: Khalaf Ali A. , Awad Ibrahim M. , El‐Emary Talaat I. , El‐Aal Hassan A. K. Abd
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Direct Catalytic Asymmetric Olefin Metathesis. Selectivity Control by Enoate and Ynoate Groups in Ru‐Catalyzed Asymmetric Ring‐Opening/Cross‐Metathesis.
Authors: Giudici Russell E. , Hoveyda Amir H.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Photoacylation of Alcohols in Neutral Medium.
Authors: Debieux Jean‐Luc , Cosandey Anne , Helgen Celine , Bochet Christian G.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Enantioselective Alkylation of Acyclic α,α‐Disubstituted Tributyltin Enolates Catalyzed by a {Cr(salen)} Complex.
Authors: Doyle Abigail G. , Jacobsen Eric N.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Three‐Component Reactions of α‐ and β‐Bromo Aldehydes with Amides and Dienophiles — An Easy Way to Versatile 1‐Amido‐2‐cyclohexenes.
Authors: Huebner Sandra , Neumann Helfried , Michalik Dirk , Klaus Stefan , Struebing Dirk , Spannenberg Anke , Jacobi von Wangelin Axel , Beller Matthias
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Heck Arylations of Pent‐4‐enoates or Allylmalonate Using a Palladium/Tetraphosphine Catalyst.
Authors: Lemhadri Mhamed , Battace Ahmed , Zair Touriya , Doucet Henri , Santelli Maurice
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Diazo Preparation via Dehydrogenation of Hydrazones with “Activated” DMSO.
Authors: Javed Muhammad I. , Brewer Matthias
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Efficient Conversion of Aromatic Amines into Azides: A One‐Pot Synthesis of Triazole Linkages.
Authors: Barral Karine , Moorhouse Adam D. , Moses John E.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of Substituted 2‐Hydroxyaryl Aldehydes by the Microwave‐Induced Reimer—Tiemann Reaction.
Authors: Vibhute Yeshwant B. , Lonkar Subhash M. , Sayyed Mudassar A. , Baseer Mohammad A.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.