bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibrational characterization of E102 food additive by Raman and surface‐enhanced Raman spectroscopy and theoretical studies
Authors: Peica N. , Pavel I. , Cîntǎ Pînzaru S. , Rastogi V. K. , Kiefer W. 
Published: July 2005

AbstractThe well‐known food dye E102 could be detected in aqueous solutions by means of regular Raman and surface‐enhanced Raman scattering (SERS) spectroscopy at micromolar and nanomolar levels, respectively. The changes observed in the profile of the band at 1365 cm−1, characteristic of the ν(NN) mode of the azo chromophore group, allowed us to establish the present species in the Raman and SERS solutions at different concentrations or pH values. Protonation at the azo group of the molecule was detected for acidic pH values <3. In the pH range 3–8, no changes in the molecular species were observed. Density functional theory (DFT)‐calculated geometries, harmonic vibrational modes and Raman scattering activities for E102 were in good agreement with the experimental data, a complete vibrational assignment being proposed. A strong chemical interaction of E102 with colloidal particles was evidenced and an adsorbed geometry was proposed. Copyright © 2005 John Wiley & Sons, Ltd.
The ‘chemical’ (electronic) contribution to surface‐enhanced Raman scattering
Authors: Otto Andreas 
Published: July 2005

AbstractThe model of surface‐enhanced Raman scattering (SERS) by time‐dependent evolution in the intermediate anionic state of the adsorbate is analogous to intramolecular Franck–Condon resonance Raman scattering. For adsorbates with a π* state, the residence time of some femtoseconds (10−15 s) in the anionic state leads to a separation of electron (e) and hole (h), which quenches SERS at a smooth surface. At so‐called SERS‐active sites, the residence time of the hole is enhanced and therefore there is no final e–h pair and the excitation of only a molecular vibration leads to SERS. In contrast, for molecules with only high‐energy σ* states, the residence time in the anionic state is <1 fs (analogous to the impulse mechanism in electron scattering), and the creation of e–h pairs is less likely. This leads to first‐layer electronic Raman scattering, especially by CH stretch vibrations with an average enhancement of about 30–40‐fold. Copyright © 2005 John Wiley & Sons, Ltd.
Field enhancement and molecular response in surface‐enhanced Raman scattering and fluorescence spectroscopy
Authors: Käll Mikael , Xu Hongxing , Johansson Peter 
Published: July 2005

AbstractWe present a theoretical analysis of surface‐enhanced Raman scattering and fluorescence emission from chromophoric molecules located at electromagnetic ‘hot spots’ in nanoparticle aggregates. The model combines classical electrodynamic enhancement effects with molecular quantum dynamics and allows us to quantify various molecular cross‐sections and spectral properties. For a model molecule that simulates rhodamine 6G, we find that an electromagnetic Raman enhancement of the order of 1010 results in an effective Raman cross‐section of the order of 10−14 cm2, in agreement with single‐molecule Raman measurements. Copyright © 2005 John Wiley & Sons, Ltd.
Surface‐enhanced Raman spectroscopy: a brief retrospective
Authors: Moskovits Martin 
Published: July 2005

AbstractThe electromagnetic theory of surface‐enhanced Raman spectroscopy (SERS), despite its simplicity, can account for all major SERS observations, including: the need for a nanostructured material as the SERS‐active system; the observation that some metals form good SERS‐active systems while others do not; the observation that strongly interacting metal nanoparticles result in very much more effective SERS‐active systems; the observed polarization sensitivity shown by nanoparticle aggregates; and the optical behavior of nanostructured metals in the absence of a molecular adsorbate. By extending the ideas inherent in the electromagnetic model one can also understand the seminal features reported for single‐molecule SERS, including the puzzling observation that only a few silver ‘particles’ in an ensemble are ‘hot’ (they are appropriately structured nanoparticle clusters) and that for a hot particle, once one is able to observe SERS, adding more adsorbate does not significantly alter the intensity (once the electromagnetic hot spot is occupied, adding adsorbate to other sites on the nanoparticle cluster will not add greatly to the observed intensity). However, the electromagnetic model does not account for all that is learned through SERS. Molecular resonances, charge‐transfer transitions and other processes such as ballistic electrons transiently probing the region where the molecule resides and then modulating electronic processes of the metal as a result certainly contribute to the rich information SERS reports; and by virtue of the fact that these contributions will vary from molecule to molecule, they will constitute the most interesting aspects reported by SERS. But, the overall reason why SERS produces such inordinate enhancements is largely an electromagnetic property of nanostructures. Copyright © 2005 John Wiley & Sons, Ltd.
Improved surface‐enhanced Raman scattering of polypyrrole electrodeposited on roughened substrates composed of Au–Ag bimetallic nanoparticles
Authors: Chuang Thomas C. , Liu Yu‐Chuan , Wang Chee‐Chan 
Published: July 2005

AbstractWe report here the first electrochemical method to prepare a roughened gold substrate with bimetallic silver and gold nanoparticles. First, a silver substrate was roughened by a triangular‐wave oxidation–reduction cycle in 0.1 N HCl aqueous solutions. Silver‐containing complexes were found in the solution after the ORC treatment. Then a gold substrate was subsequently roughened by a similar oxidation–reduction treatment in this solution. Scanning electron microscopy and atomic force microscopy reveal that the surface of the roughened gold was intrinsically modified with silver nanoparticles, which demonstrates two different kinds of deposition domains. Encouragingly, surface‐enhanced Raman scattering of polypyrrole electrodeposited on the roughened gold substrate, modified with finer silver nanoparticles, exhibits an eightfold higher intensity. Copyright © 2005 John Wiley & Sons, Ltd.
Surface‐enhanced hyper‐Raman and surface‐enhanced Raman scattering from molecules adsorbed on nanoparticles‐on‐smooth‐electrode (NOSE) substrate I. Pyridine, pyrazine and benzene
Authors: Li Xiao‐Yuan , Huang Qun‐Jian , Petrov Vladimir I. , Xie Yu‐Tao , Luo Qi , Yu Xiangyang , Yan Yi‐Jing 
Published: July 2005

AbstractMetal nanoparticles‐on‐smooth‐electrode (NOSE) was used as the substrate in a potential‐dependent surface‐enhanced hyper‐Raman(SEHRS), hyper‐Rayleigh(SEHRyS) and Raman (SERS) study of adsorbed molecules of pyridine, pyrazine and benzene. The three molecules are chosen because they are known to adsorb in different orientations on an Ag surface, thus allowing us to examine the sensitivity of SEHRS and SERS signals to the orientation of adsorbed molecules on the NOSE substrate. A computational subroutine is developed and interfaced with Gaussian‐98 to calculate the numeric infrared, Raman and hyper‐Raman intensities, as well as their projections along any molecular‐fixed orientation axis at the level of finite perturbation theory. In this study, we tried to make four types of systematic comparisons. First, we compared the performance of Agn|Ag NOSE substrate with that of traditional substrates such as a randomly roughened Ag electrode or a randomly aggregated Ag sol in SEHRS and SERS. Secondly, we tried to compare between infrared, Raman and hyper‐Raman spectra, which represent the parity‐differentiated one‐photon, two‐photon and three‐photon processes, respectively, with the aim of examining the complementarity between SEHRS and SERS as well as between SEHRS and infrared absorption. Thirdly, we compared isotropic normal spectra with surface‐enhanced spectra (SEHRS and SERS), with the aim of examining the effect of surface adsorption on the selectivity and enhancement. Lastly, we made a systematic comparison between the observed and calculated spectra for both isotropic and surface spectra, which allowed us to assign and interpret the observed data and to infer the most likely orientation of the adsorbed molecules. The NOSE method can be generalized easily to other metal nanoparticles dispersed on a smooth inert metal electrode. The rapid development in the synthesis of metal nanoparticles of various sizes, shapes and crystalline states makes the NOSE method a much more flexible and versatile substrate in the study and applications of SERS and SEHRS techniques. Copyright © 2005 John Wiley & Sons, Ltd.
Nanoparticles‐on‐electrode approach for in situ surface‐enhanced Raman spectroscopy studies with platinum‐group metals: examples and prospects
Authors: Gómez Roberto , Solla‐Gullón José , Pérez Juan M. , Aldaz Antonio 
Published: July 2005

AbstractSurface‐enhanced Raman spectroscopy (SERS) spectra have been obtained for different species (CO, CN−, ethylene and oxalic acid) adsorbed on nanostructured electrodes prepared by deposition of Pt, Pd, Rh and Pd:Pt nanoparticles on either gold or platinum electrodes. These examples not only refer to stable adlayers of typical adsorbates, such as carbon monoxide and cyanide, but also to adsorbates that may be easily either reduced or oxidized at some of these metals, such as ethylene and oxalic acid. On the other hand, the SERS spectrum of CO adsorbed on a transition metal alloy (Pd/Pt = 1) electrode is obtained for the first time. Taking advantage of the high surface enhancement factor found for these nanostructured samples (∼550 for CN− on Pt at − 0.4 V/SCE), ethylene and oxalic SER spectra are obtained for pure platinum electrodes. The importance of the charge‐transfer mechanism for the enhancement in the case of Pt is evidenced according to the ratio of the band intensities for CO or CN− to the oxalic ones. Specific advantages of the nanoparticles‐on‐electrode approach are highlighted. Copyright © 2005 John Wiley & Sons, Ltd.
Effects of dietary carbohydrate sources on degradation kinetics of nitrogen from plant protein sources in the rumen
Authors: Guedes Cristina M , Dias‐da‐Silva Arnaldo 
Published: July 2005

AbstractThe effects of the nature of carbohydrate source on in sacco protein degradation of 15 samples of plant protein sources were studied in four mature fistulated rams fed a control diet (C) of meadow hay and soyabean meal (83:15 on dry matter basis) and three diets in which 36, 34 or 40% of diet dry matter was sugar beet pulp, maize or wheat (diets P, M and W respectively). Degradation parameters were estimated from the exponential equation p = a + b[1 − exp(−ct)]. Diet composition significantly affected (P < 0.001) all the degradation parameters, the effect being more pronounced on the degradation rate (c). This parameter was stimulated (P < 0.05) by beet pulp but depressed (P < 0.05) by cereal inclusion in the diets, in particular when animals were fed the W diet (4.46, 5.65, 3.74 and 3.05% h−1 for the C, P, M and W diets respectively). An interaction effect between carbohydrate source and incubated plant protein sources was observed (P < 0.001). The reason(s) for these differential effects were not elucidated. The practical consequences of these findings are discussed. Copyright © 2005 Society of Chemical Industry
Effects of batters containing different gum types on the quality of deep‐fat fried chicken nuggets
Authors: Sahin Serpil , Sumnu Gulum , Altunakar Bilge 
Published: July 2005

AbstractThe effects of various gum types [hydroxypropylmethylcellulose (HPMC), guar gum, xanthan gum, gum arabic] on the quality of deep‐fat fried chicken nuggets were studied. Chicken samples, 0.04 m in diameter and 0.015 m in thickness taken from the breast portion, were coated with batters composed of a 3:5 solid to water ratio by immersion. The solid content of batter formulations contained equal amounts of corn and wheat flours, 1.0% gum, 1.0% salt and 0.5% leavening agent. As control, batter without gum addition was used. Samples were fried at 180 °C for 3, 6, 9 and 12 min. The hardness and oil content of the chicken nuggets increased whereas the moisture content decreased during frying. HPMC and xanthan gums reduced oil absorption significantly compared with other gums and the control. When gum arabic was added to the batter formulation, a product with the highest oil content and porosity was obtained. Copyright © 2005 Society of Chemical Industry
In Situ‐Gelling, Erodible N‐Isopropylacrylamide Copolymers
Authors: Lee Bae Hoon , Vernon Brent 
Published: July 2005

AbstractSummary: Copolymers of N‐isopropylacrylamide, 2‐hydroxyethyl methacryl lactate [(HEMA)‐lactate] and acrylic acid (AAc) were prepared with varying mole ratios of monomers to develop copolymers with gelation properties above a certain concentration for a bioerodible, in‐situ gelling material. The copolymers formed gels in situ under physiological condition. The gelation temperature of the copolymers decreased as the HEMA‐lactate content of the copolymers increased due to the hydrophobicity of HEMA‐lactate, and increased as the AAc content increased due to the hydrophilicity of AAc. The gels redissolve at 37 °C as their LCSTs increase above 37 °C due to the hydrolysis of the HEMA‐lactate pendant groups.
magnified image
Poly(lactide) Stereocomplexes: Formation, Structure, Properties, Degradation, and Applications
Authors: Tsuji Hideto 
Published: July 2005

AbstractSummary: Poly(lactide)s [i.e. poly(lactic acid) (PLA)] and lactide copolymers are biodegradable, compostable, producible from renewable resources, and nontoxic to the human body and the environment. They have been used as biomedical materials for tissue regeneration, matrices for drug delivery systems, and alternatives for commercial polymeric materials to reduce the impact on the environment. Since stereocomplexation or stereocomplex formation between enantiomeric PLA, poly(L‐lactide) [i.e. poly(L‐lactic acid) (PLLA)] and poly(D‐lactide) [i.e. poly(D‐lactic acid) (PDLA)] was reported in 1987, numerous studies have been carried out with respect to the formation, structure, properties, degradation, and applications of the PLA stereocomplexes. Stereocomplexation enhances the mechanical properties, the thermal‐resistance, and the hydrolysis‐resistance of PLA‐based materials. These improvements arise from a peculiarly strong interaction between L‐lactyl unit sequences and D‐lactyl unit sequences, and stereocomplexation opens a new way for the preparation of biomaterials such as hydrogels and particles for drug delivery systems. It was revealed that the crucial parameters affecting stereocomplexation are the mixing ratio and the molecular weight of L‐lactyl and D‐lactyl unit sequences. On the other hand, PDLA was found to form a stereocomplex with L‐configured polypeptides in 2001. This kind of stereocomplexation is called “hetero‐stereocomplexation” and differentiated from “homo‐stereocomplexation” between L‐lactyl and D‐lactyl unit sequences. This paper reviews the methods for tracing PLA stereocomplexation, the methods for inducing PLA stereocompelxation, the parameters affecting PLA stereocomplexation, and the structure, properties, degradation, and applications of a variety of stereocomplexed PLA materials.
magnified image
High Temperature Thermosets With a Low Coefficient of Thermal Expansion
Authors: Wippl Johann , Schmidt Hans‐Werner , Giesa Reiner 
Published: July 2005

AbstractSummary: Polymeric thermosetting composites can be used as metal substitutes for certain applications if they possess high temperature stability in air, low coefficient of thermal expansion (CTE), and sufficient flexural strength, in combination with competitive costs. Commercial bismaleimide, bisnadimide, and cyanate ester thermosetting materials were selected due to their excellent thermal stability. Low CTEs were achieved by adding high loading levels of fused silica or silicon nitride fillers. Several optimized composites were fabricated by varying the materials, composition, and cure conditions. Characteristic composite properties, such as CTE, thermal stability, glass transition temperature (Tg), flexural strength, and filler distribution were investigated. The best system developed consists of Matrimide 5292, a commercial two‐component bismaleimide resin, filled with 75% Silbond FW100EST, and additionally reinforced with 0.5% Twaron short fibers. This composite is distinguished by a CTE around 15 ppm · K−1, a Tg around 340 °C, flexural strength above 100 MPa, and attractive material costs.Matrimid 5292 (75%)/Silbond FW100AST (24.5%), and Twaron 2 mm short fibers (0.5%). Three fibers are visible, embedded and well dispersed in the matrix.magnified imageMatrimid 5292 (75%)/Silbond FW100AST (24.5%), and Twaron 2 mm short fibers (0.5%). Three fibers are visible, embedded and well dispersed in the matrix.
New Organic Dispersions of Conducting Polymers Using Polymeric Ionic Liquids as Stabilizers
Authors: Marcilla Rebeca , Ochoteco Estibalitz , Pozo‐Gonzalo Cristina , Grande Hans , Pomposo Jose A. , Mecerreyes David 
Published: July 2005

AbstractSummary: Polypyrrole (PPy), polyaniline (PANI), and poly(ethylenedioxythiophene) (PEDOT) aqueous dispersions were prepared by polymerizing the corresponding monomer in the presence of a polymeric ionic liquid (PIL), poly(1‐vinyl‐3‐ethylimidazolium bromide). By addition of bispentafluoroethanesulfonimide lithium salt, the PIL stabilizer becomes hydrophobic and precipitates in water and traps the conducting polymer microparticles inside. The dispersion of the recovered powders in organic solvents leads to organic conducting dispersions. After casting the organic dispersions, hydrophobic films with electrical conductivity values as high as 0.1 S · cm−1 were obtained.A new synthetic route to new organic dispersions.magnified imageA new synthetic route to new organic dispersions.
Context moderates illness‐induced lifestyle disruptions across life domains: a test of the illness intrusiveness theoretical framework in six common cancers
Authors: Devins Gerald M. , Bezjak Andrea , Mah Kenneth , Loblaw D. Andrew , Gotowiec Andrew P. 
Published: July 2005

AbstractThe illness intrusiveness theoretical framework maintains that illness‐induced lifestyle disruptions compromise quality of life in chronic life‐threatening conditions and that this effect is moderated by social, psychological, and contextual factors. Considerable evidence indicates that lifestyle disruptions compromise quality of life in cancer and other diseases and that the effects differ across life domains. The hypothesis that contextual factors (e.g. age, education, income, stressful life events) moderate these effects has not been tested extensively. We investigated whether age, income, education, and/or recent stressful life events modify the experience of illness intrusiveness across three central life domains (Relationships and Personal Development, Intimacy, and Instrumental life) in six common cancers. A sample of 656 cancer outpatients with one of six common cancers (breast, prostate, lymphoma, lung, head and neck, and gastrointestinal, all n's>100) completed the Illness Intrusiveness Ratings Scale while awaiting follow‐up appointments with an oncologist. Results indicated statistically significant (all p's<0.05) interactions involving each of the hypothesized moderator variables and the Life Domain factor. In each case, greatest divergence was evident when illness intrusiveness involved instrumental life domains (e.g. work, finances, health, and active recreation). The findings substantiate the illness intrusiveness theoretical framework and support its relevance for people with cancer. The psychosocial impact of chronic life‐threatening disease differs across life domains and depends on the context in which it is experienced. Copyright © 2005 John Wiley & Sons, Ltd.
Fourteenth International Summer School on Vacuum, Electron and Ion Technologies (VEIT)
Authors: Guerassimov Nikolay 
Published: July 2005

AbstractPlasma News: This section contains news of the plasma community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of Plasma Processes and Polymers, preferably by E‐mail to plasma@wiley‐vch.de. The editorial office decides which articles will be published.
Effect of local field correction in screening dependence of superconducting state parameters for Be90Al10 and Be70Al30 metallic glasses
Authors: Sharma Renuka , Gupta Manish , Khan Haniph 
Published: July 2005

AbstractThe superconducting state parameters (SSP) viz. electron–phonon coupling strength (λ), Coulomb pseudopotential (μ*), transition temperature (Tc), isotope effect exponent (α) and interaction strength (N0V) for two metallic glasses, i.e. Be90Al10 and Be70Al30, have been investigated by extending the BCS–Eliasberg–McMillan formalism for the metallic glass superconductors incorporating the effect of local field correction in dielectric screening functions which in turn become prominent in determining superconducting state parameters of the metallic glasses under consideration. We have employed eleven forms of dielectric screening functions – viz. Hartree, RPA, Modified Hubbard, Overhauser, Geldart–Vosko, Animalu, King–Cutler, SCS, Vashistha–Singwi, Ichimaru–Utsumi, and Farid et al. – in conjunction with Ashcroft's potential to predict superconducting state parameters. It is observed that the values of SSP are quite sensitive to the form of dielectric screening functions. In conclusion the present computed values of SSP for the RPA form of dielectric screening are in good agreement with the experimental values and other theoretical results for both glassy materials, which confirms the validity of the proposed formalism. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The influence of Sc substitution on some physical properties of ScxHo1–xNi2 solid solutions
Authors: Ćwik J. , Palewski T. , Nenkov K. , Burkhanov G. S. , Chistyakov O. D. , Warchulska J. 
Published: July 2005

AbstractResults of X‐ray diffraction analysis, magnetization measurements, magnetic susceptibility, electrical resistivity, and heat capacity performed on polycrystalline ScxHo1–xNi2 (0 ≤ x ≤ 1) solid solutions are reported. It was found that they crystallize with the formation of the C15 type Laves‐phase superstructure. At low temperatures (below 20 K), the ScxHo1–xNi2 solid solutions with 0 ≤ x ≤ 0.6 are ferromagnets. At higher temperatures, all solid solutions are Curie–Weiss paramagnets. Temperature dependences of the electrical resistivity exhibit the typical behaviour of metals. The heat capacity measurements allowed us to determine the Debye temperature. The magnetocaloric effect was estimated from measurements performed in a low magnetic field of 0.42 T. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)