bluuebunny/crossref_metadata_2025 huggingface dataset:
The ‘chemical’ (electronic) contribution to surface‐enhanced Raman scattering
Authors: Otto Andreas
Published: July 2005

The 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

We 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

The 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

We 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

Metal 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

Surface‐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

The 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

The 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

Summary: 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.

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Poly(lactide) Stereocomplexes: Formation, Structure, Properties, Degradation, and Applications
Authors: Tsuji Hideto
Published: July 2005

Summary: 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.

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High Temperature Thermosets With a Low Coefficient of Thermal Expansion
Authors: Wippl Johann , Schmidt Hans‐Werner , Giesa Reiner
Published: July 2005

Summary: 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.

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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.
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

Summary: 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.

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A 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

The 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

Plasma 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

The 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

Results 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)
Semi‐classical calculation of resonant states of a charged particle interacting with a metallic surface
Authors: Zuluaga John Jairo , Mahecha Jorge , Chulkov Eugene
Published: July 2005

We assess the applicability of the semi‐classical approach of Herman–Kluk with filter diagonalization to determine resonant states of either the electron‐surface system or the ion‐surface system. An effective potential model of the interaction of an electron with a ruthenium metallic surface is used. The evolution of the wave‐function and the resonant states of this system are calculated. Analogous results for the interaction of the system formed by the H− and the ruthenium surface are presented. For the calculation of the resonances, the semi‐classical wave‐function is found, and the autocorrelation function between the initial and final wave‐functions is calculated, from which the position and width of the resonances are extracted by using the harmonic inversion by filter diagonalization. The results are compared with results available in the literature for similar models obtained by quantum calculations using fast Fourier Transform. The positions of the lower‐lying resonances found with the semi‐classical and quantum approaches match closely, while the values of the widths of the resonances show larger discrepancies. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heat capacity and thermodynamic functions of the CuAlS2 semiconductor in the temperature range from 80 to 300 K
Authors: Korzun B. V. , Mianzelen R. R. , Sheleg A. U. , Tekhanovich N. P. , Bente K. , Schmitz W.
Published: July 2005

The molar heat capacity at constant pressure CP has been measured for CuAlS2 semiconductor in the temperature range from 80 to 300 K for the first time. From the experimental results the molar heat capacity at constant volume CV and thermodynamic functions such as enthalpy H and entropy S were calculated. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant enhancement of third‐order nonlinear optical property in J‐like aggregates of a cyanine dye
Authors: Li Zhongyu , Jin Zhao‐hui , Kasatani Kazuo , Okamoto Hiroaki , Takenaka Shunsuke
Published: July 2005

The wavelength dependence of the third‐order optical nonlinearity and response of the J‐like aggregates of a cyanine dye called NK‐3261 in a neat film were measured by the femtosecond degenerate four‐wave mixing (DFWM) technique under resonant conditions. The temporal profile of the DFWM signal of NK‐3261 J‐like aggregates was found to consist of three components, i.e., coherent instantaneous nonlinear response (electronic response) and the two slow responses with decay time constants of ca. 0.9 ps and ca. 5.6 ps. The electronic component of the effective third‐order nonlinear optical susceptibility, χ(3)e, of NK‐3261 J‐like aggregates was as high as ca. 5 × 10−7 esu at 850 nm. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phenomenological description of domain recording in ferroelectric semiconductors by using atomic force microscopy
Authors: Morozovska Anna N. , Eliseev Eugene A.
Published: July 2005

The equilibrium sizes of domains caused by the electric field of the atomic force microscope tip in ferroelectric semicon‐ductor crystals have been calculated. The domain was consi‐dered as a prolate semi‐ellipsoid with rather thin domain walls. For the first time we modified the Landauer model al‐lowing for semiconductor properties of the sample and the surface energy of the domain butt. The free carriers inside the crystal lead to the formation of a screening layer around the domain, which partially shields its interior from the depolari‐zation field. The obtained dependence of domain radius on applied voltage is in a good quantitative agreement with the ones of submicron ferroelectric domains recorded by high‐voltage atomic force and scanning probe microscopy in LiNbO3, BaTiO3and RbTiOPO4crystals. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Command algebras, recursion and program transformation
Authors: Hesselink Wim H.
Published: July 2005

Dijkstra's language of guarded commands is extended with recursion and transformed into algebra. The semantics is expressed in terms of weakest preconditions and weakest liberal preconditions. Extreme fixed points are used to deal with recursion. Unbounded nondeterminacy is allowed. The algebraic setting enables us to develop efficient transformation rules for recursive procedures. The main result is an algebraic version of the rule of computational induction. In this version, certain parts of the programs are restricted to finite nondeterminacy. It is shown that without this restriction the rule would not be valid. Some applications of the rule are presented. In particular, we prove the correctness of an iterative stack implementation of a class of simple recursive procedures.
Partial order behaviour and structure of Petri nets
Authors: Best Eike , Desel Jörg
Published: July 2005

This paper argues that partial order semantics can be used profitably in the proofs of some nontrivial results in Petri net theory. We show that most of Commoner's and Hack's structure theory of free choice nets can be phrased and proved in terms of partial order behaviour. The new proofs are considerably shorter (and, arguably, more lucid) than the old ones; they also generalise the results from (safe) free choice nets to (bounded) extended free choice nets.
Axioms and models of linear logic
Authors: Hesselink Wim H.
Published: July 2005

Girard's recent system of linear logic is presented in a way that avoids the two-level structure of formulae and sequents, and that minimises the number of primitive function symbols. A deduction theorem is proved concerning the classical implication as embedded in linear logic. The Hilbert-style axiomatisation is proved to be equivalent to the sequent formalism. The axiomatisation leads to a complete class of algebraic models. Various models are exhibited. On the meta-level we use Dijkstra's method of explicit equational proofs.
Equational reasoning about nondeterministic processes
Authors: Misra Jayadev
Published: July 2005

A deterministic message-communicating process can be characterised by a “continuous” function
f
which describes the relationship between the inputs and the outputs of the process. The operational behaviour of a network of deterministic processes can be deduced from the least fixpoint of a function
g
, where
g
is obtained from the functions that characterise the component processes of the network. We show in this paper that a nondeter-ministic process can be characterised by a “description” consisting of a pair of functions. The behaviour of a network consisting of such processes can be obtained from the “smooth” solutions of the descriptions characterising its component processes. The notion of smooth solution is a generalisation of least fixpoint. Descriptions enjoy the crucial property that a variable may be replaced by its definition.
Modelling multiple inheritance with colimits
Authors: Lin Huimin , Pong Man-Chi
Published: July 2005

A categorical semantics of multiple inheritance is presented, in which the inheritance relations between program entities are represented as commutative diagrams in a suitable category, and multiple inheritance is then modelled with colimits of such diagrams. It is shown that the informal semantics of multiple inheritance used in existing object-oriented programming languages conforms to, or is consistent with, this model.
Proof obligations for blocks and procedures
Authors: Ah-kee Alain
Published: July 2005

Operation decomposition proof obligations are given for a language with blocks and unrestricted procedure calls with reference parameters and global variables. Post-conditions of the initial and final states of the computation are used; existing proof rules are for post-conditions which are predicates of the final state only. Aliasing, as arising from reference parameters, and static scoping are dealt with in the Hoare-like proof system by the use of a “syntactic environment”.
X-machines and the halting problem: Building a super-turing machine
Authors: Stannett Mike
Published: July 2005

We describe a novel machine model of computation, and prove that this model is capable of performing calculations beyond the capability of the standard Turing machine model. In particular, we demonstrate the ability of our model to solve the Halting problem for Turing machines. We discuss the issues involved in implementing the model as a physical device, and offer some tentative suggestions.
On the interconnection constants of Hopfield nets
Authors: Soparkar Nandit , Silberschatz Abraham
Published: July 2005

Hopfield nets are a class of neural networks that are often applied to optimisation problems. The role played by certain constants appearing in the interconnections are crucial to the computations. A bad choice of constant values results in the convergence of the system to states that represent extraneous results. This paper examines a discrete model of the nets which allows a better characterisation of the constants. The formal approach followed in this paper allows the specification of values to the constants that ensure convergence of the system to states that represent results that are not extraneous. Using the Hopfield nets terminology, we have identified methods to remove extraneous energy minima in the discrete version of the system. Since any simulation study of Hopfield nets on real computers must use discretised approximations to analog values, the results are of interest in a practical domain as well.
Defining, analysing and implementing communication protocols using attribute grammars
Authors: Chapman N. P.
Published: July 2005

A new approach to describing communication protocols is introduced. In the style of a formal language, the protocol is considered as the set of all legal sequences of symbols that can be exchanged by the communicating processes. Although context free grammars cannot adequately describe such sequences, it is shown that attribute grammars may be used. Examples are given which show that common protocol features such as interleaving, windowing and flow control can be described by attribute grammars.

It is shown how deadlock-proneness of a protocol can be formalised as a property of its attribute grammar specification, and the undecidability of deadlock-proneness for arbitrary grammars is proved. An algorithm is given for determining whether a protocol is deadlock-prone in the decidable case.

A method of automatically implementing protocols from their specifications is described. The implementation takes the form of a pair of communicating attributed pushdown automata. These are based on LR(0) parsers, with attribute evaluation being performed in parallel with the parse; attribute values are used to help direct the parse. Consideration is also given to the handling of errors.
Unpacking the depersonalization syndrome: an exploratory factor analysis on the Cambridge Depersonalization Scale
Authors: SIERRA MAURICIO , BAKER DAWN , MEDFORD NICHOLAS , DAVID ANTHONY S.
Published: July 2005

Background. Depersonalization has long been considered a syndrome but there is poor agreement on its constituent symptoms.

Method. In order to establish whether different symptoms of depersonalization represent the expression of a single or several underlying dimensions, an exploratory factor analysis on the Cambridge Depersonalization Scale (CDS) was carried out on 138 consecutive patients diagnosed with depersonalization disorder.

Results. Four well determined factors accounting for 73·3% of the variance were extracted. These were labelled ‘Anomalous Body Experience’; ‘Emotional Numbing’; ‘Anomalous Subjective Recall’ and ‘Alienation from Surroundings’.

Conclusions. Symptoms of depersonalization belong to distinct but related psychopathological domains.
Does adolescent depression predict obesity in black and white young adult women?
Authors: FRANKO DEBRA L. , STRIEGEL-MOORE RUTH H. , THOMPSON DOUGLAS , SCHREIBER GEORGE B. , DANIELS STEPHEN R.
Published: July 2005

Background. To examine whether adolescent depressive symptoms predict young adult body mass index (BMI) and obesity in black and white women.

Method. Participants included 1554 black and white adolescent girls from the National Heart, Lung, and Blood Institute Growth and Health Study (NGHS) who completed the Center for Epidemiological Studies – Depression Scale (CES-D) at ages 16 and 18 years.

Results. Regression analyses showed that depressive symptoms at both ages 16 and 18 were associated with increased risk of obesity (BMI[ges ]30) and elevated BMI in young adulthood (age 21) in both black and white girls. Black girls exhibited a significantly greater likelihood of obesity and higher BMI (i.e. a main effect of race), but the race×CES-D interaction was not significant in any analysis.

Conclusions. Depressive symptoms in adolescence appear to be predictive of obesity and elevated BMI in early adulthood for both black and white girls, even when taking prior BMI into account, indicating that depressive symptoms confer risk for obesity above and beyond the known tracking of body weight. Obesity prevention studies might consider assessing depressive symptoms in adolescence in order to more fully capture important risk variables.
Neuregulin 1 (NRG1) and schizophrenia: analysis of a US family sample and the evidence in the balance
Authors: DUAN JUBAO , MARTINEZ MARIA , SANDERS ALAN R. , HOU CUIPING , KRASNER AARON J. , SCHWARTZ DANIEL B. , GEJMAN PABLO V.
Published: July 2005

Background. Individual genome-wide linkage scans and meta-analyses support that one or more susceptibility genes for schizophrenia are located in chromosome 8p. A gene from this region, neuregulin 1 (NRG1), known to be involved with glutamatergic function, has been found to be associated in some studied samples.

Method. We have examined a new combined schizophrenia sample with 136 schizophrenia families largely of European ancestry (EA) and 646 subjects with DNA. We genotyped 14 single nucleotide polymorphisms (SNPs) in NRG1 including those reported to comprise schizophrenia-associated haplotypes in Icelandic, Scottish, Irish, and Chinese Han populations.

Results. We found no evidence of association at a single-marker or a haplotypic level. We review methodological aspects of previous studies to enable us to put our findings into context.

Conclusions. Our failure to find an association between NRG1 and schizophrenia might reflect different linkage disequilibrium (LD) patterns found in different populations, disease allelic heterogeneity, clinical heterogeneity of schizophrenia, or inadequate statistical power deriving from moderate sample size. NRG1, if a true gene for schizophrenia, accounts for a small fraction of the disease in most populations. The confirmation of NRG1 as a schizophrenia susceptibility gene will require studies with a comprehensive set of markers and in larger samples. The possibility remains that reports of NRG1 association might reflect false positives.
Conservation units: a new deforestation frontier in the Amazonian state of Rondônia, Brazil
Authors: PEDLOWSKI M.A. , MATRICARDI E.A.T. , SKOLE D. , CAMERON S.R. , CHOMENTOWSKI W. , FERNANDES C. , LISBOA A.
Published: July 2005

Over the past several decades, the Brazilian State of Rondônia has been the destination of many rural migrants drawn from Brazil's middle southern regions by massive government colonization projects. Factors such as explosive population growth, logging, mining, small-scale farming and ranching have synergistically fuelled deforestation in the state. The total area deforested in Rondônia in 1978 was 4200 km2. In 1988, the area increased to 30 000 km2, in 1998 to 53 300 km2 and by the year 2003, a total of 67 764 km2 of Rondônia was deforested. In response to the high rate of deforestation observed in Rondônia and other Amazonian states, state and federal agencies worked to create a network of conservation units (CUs) in Brazil during the 1990s that was signed into law(Law 9985/00) in 2000. The ability of these CUs to reduce the rate of deforestation was analysed. Remotely-sensed data from Landsat and thematic coverages were used to measure deforestation inside all CUs in Rondônia. A more detailed analysis of CUs with the highest levels of deforestation, including an analysis between soil types and deforestation and a forecast of potential future deforestation, was conducted. The creation of conservation units in Rondônia has been useful in curbing deforestation within their boundaries; however, many CUs face pressure from the combined activities of illegal loggers, cattle ranchers and small-scale farmers seeking new sources of timber and agricultural land. For example, an exponential increase in the amount of deforestation was observed in Rondônia's Bom Futuro National Forest between 1992 and 2000. A regression model indicated a total of 20 500 ha deforested by 2002, while measurements from 2002 imagery showed an actual total deforestation of 20 720 ha. Should this trend persist, Bom Futuro National Forest could be completely deforested by 2017. CUs in Rondônia must be developed and implemented jointly by all stakeholders through the creation of partnerships between local communities, non-governmental organizations and government agencies.
Public pensions and international migration: some clarifications and illustrative results
Authors: MUNZ SONJA , WERDING MARTIN
Published: July 2005

Immigration is often thought of as a measure suited to mitigate the fiscal consequences of demographic ageing for unfunded public pension schemes. Building on Sinn (1997), the paper explores in some more detail the conditions under which immigrants are a net fiscal asset for national pension budgets not only on a temporary basis – i.e., as long as they are paying contributions and before they start drawing benefits – but also in the long run. Illustrative simulations are provided for the cases of Germany, Italy, the UK, and the US. It turns out that the value of immigrants depends on the nature of the pension scheme (Bismarck vs Beveridge). Also, it is strongly affected by the immigrants' characteristics in terms of skills and fertility. Furthermore, effects differ substantially for the cases of temporary vs permanent migration.
Social security personal-account participation with government matching
Authors: ENGELHARDT GARY V. , KUMAR ANIL
Published: July 2005

This paper examines the potential impact of government matching contributions on personal-account participation in the President's Commission on Strengthening Social Security's Model 3 for Social Security reform. Given the government's choice of four plan-design parameters, the magnitude of the match is determined solely by the differential return personal-account assets receive above the notional return, referred to as the ‘personal-account premium’, akin to the equity premium. The impact of matching on personal-account participation is simulated for older workers (ages 40 to 65) in the first wave of the Health and Retirement Study (HRS) using empirical estimates from a structural model of the impact of employer matching on participation in corporate 401(k) plans. For a personal-account premium of three percentage points, which implies a match rate of 7.5% for middle- to lower-income workers, the simulations imply that 72% of mid-career and older workers would participate in voluntary personal accounts. The response of participation to matching is very inelastic; it seems not unlikely that participation by mid-career and older workers would achieve the mid-range assumption by the Commission of 67%. There is substantial heterogeneity in participation across subsets of older workers: participation would be the lowest for low-educated, minority, female, and unmarried mid-career and older workers.
Potential of ketamine and midazolam, individually or in combination, to induce apoptotic neurodegeneration in the infant mouse brain
Authors: Young Chainllie , Jevtovic‐Todorovic Vesna , Qin Yue‐Qin , Tenkova Tatyana , Wang Haihui , Labruyere Joann , Olney John W
Published: July 2005

Recently, it was reported that anesthetizing infant rats for 6 h with a combination of anesthetic drugs (midazolam, nitrous oxide, isoflurane) caused widespread apoptotic neurodegeneration in the developing brain, followed by lifelong cognitive deficits. It has also been reported that ketamine triggers neuroapoptosis in the infant rat brain if administered repeatedly over a period of 9 h. The question arises whether less extreme exposure to anesthetic drugs can also trigger neuroapoptosis in the developing brain.

To address this question we administered ketamine, midazolam or ketamine plus midazolam subcutaneously at various doses to infant mice and evaluated the rate of neuroapoptosis in various brain regions following either saline or these various drug treatments. Each drug was administered as a single one‐time injection in a dose range that would be considered subanesthetic, and the brains were evaluated by unbiased stereology methods 5 h following drug treatment.

Neuroapoptosis was detected by immunohistochemical staining for activated caspase‐3. It was found that either ketamine or midazolam caused a dose‐dependent, statistically significant increase in the rate of neuroapoptosis, and the two drugs combined caused a greater increase than either drug alone. The apoptotic nature of the neurodegenerative reaction was confirmed by electron microscopy.

We conclude that relatively mild exposure to ketamine, midazolam or a combination of these drugs can trigger apoptotic neurodegeneration in the developing mouse brain.

British Journal of Pharmacology (2005) 146, 189–197. doi:10.1038/sj.bjp.0706301
Selective inhibition of inhibitory kappa B kinase‐β abrogates induction of nitric oxide synthase in lipopolysaccharide‐stimulated rat aortic smooth muscle cells
Authors: Gomez Almudena Bermejo , MacKenzie Christopher , Paul Andrew , Plevin Robin
Published: July 2005

In this study, we utilised a number of adenoviral constructs in order to examine the role of intermediates of the NF‐κB pathway in the regulation of inducible nitric oxide synthase (iNOS) induction in rat aortic smooth muscle cells (RASMCs).

Lipopolysaccharide (LPS) stimulated a significant increase in iNOS induction and NF‐κB DNA binding. These parameters were substantially reduced by overexpression of a wild‐type Iκ‐Bα adenoviral construct (Ad.Iκ‐Bα), confirming a role for NF‐κB in iNOS induction.

Infection with a dominant‐negative IKKα adenoviral construct (Ad.IKKα+/−) did not significantly affect iNOS induction, NF‐κB DNA binding or Iκ‐Bα loss. Infection of RASMCs with adenovirus encoding a dominant‐negative IKKβ (Ad.IKKβ+/−) essentially abolished iNOS induction and activation of the NF‐κB pathway.

Pretreatment of RASMCs with a novel specific inhibitor of IKKβ, SC‐514, significantly reduced iNOS induction, NF‐κB DNA binding and I‐κBα loss in a concentration‐dependent manner.

In both RASMCs and human umbilical vein endothelial cells (HUVECs), infection with Ad.IKKβ+/− also inhibited COX‐2 expression in response to LPS. However, Ad.IKKα+/− was again without effect.

These data suggest that IKKβ plays a predominant, selective role in the regulation of NF‐κB‐dependent induction of iNOS in RASMCs.

British Journal of Pharmacology (2005) 146, 217–225. doi:10.1038/sj.bjp.0706308
Amadori adducts activate nuclear factor‐κB‐related proinflammatory genes in cultured human peritoneal mesothelial cells
Authors: Nevado Julián , Peiró Concepción , Vallejo Susana , El‐Assar Mariam , Lafuente Nuria , Matesanz Nuria , Azcutia Veronica , Cercas Elena , Sánchez‐Ferrer Carlos F , Rodríguez‐Mañas Leocadio
Published: July 2005

Diabetes mellitus leads to a high incidence of several so‐called complications, sharing similar pathophysiological features in several territories. Previous reports points at early nonenzymatic glycosylation products (Amadori adducts) as mediators of diabetic vascular complications. In the present study, we analysed a possible role for Amadori adducts as stimulators of proinflammatory pathways in human peritoneal mesothelial cells (HPMCs).

Cultured HPMCs isolated from 13 different patients (mean age 38.7±16 years) were exposed to different Amadori adducts, that is, highly glycated haemoglobin (10 nM) and glycated bovine serum albumin (0.25 mg ml−1), as well as to their respective low glycosylation controls. Amadori adducts, but not their respective controls, elicited a marked increase of NF‐κB activation, as determined by electromobility shift assays and transient transfection experiments.

Additionally, Amadori adducts significantly increased the production of NF‐κB‐related proinflammatory molecules, including cytokines, such as TNF‐α, IL‐1βor IL‐6, and enzymes, such as cyclooxygenase‐2 and inducible nitric oxide (NO) synthase, this latter leading to the release of NO by HPMCs.

The effects of Amadori adducts were mediated by different reactive oxygen and nitrosative species (e.g. superoxide anions, hydroxyl radicals, and peroxynitrite), as they were blunted by coincubation with the appropriate scavengers. Furthermore, NO generated upon exposure to Amadori adducts further stimulated NF‐κB activation, either directly or after combination with superoxide anions to form peroxynitrite.

We conclude that Amadori adducts can favour peritoneal inflammation by exacerbating changes in NO synthesis pathway and triggering NF‐κB‐related proinflammatory signals in human mesothelial cells.

British Journal of Pharmacology(2005)146, 268–279. doi:10.1038/sj.bjp.0706309