bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural criteria for depigmenting mechanism of arbutin
Authors: Hori Ikuyo , Nihei Ken‐ichi , Kubo Isao 
Published: July 2004

AbstractArbutin, hydroquinone‐O‐β‐d‐glucopyranoside (1) was found to inhibit the oxidation of l‐tyrosine (monophenolase activity) catalyzed by mushroom tyrosinase. However, arbutin itself was oxidized as a monophenol substrate at an extremely slow rate, and this oxidation was accelerated as soon as catalytic amounts (0.01 mm) of l‐3,4‐dihydroxyphenylalanine (l‐DOPA) became available as a cofactor. The result observed was supported by monitoring oxygen consumption. The depigmenting mechanism of arbutin previously reported is supportable if a cofactor is not available in the melanocytes. The combination with l‐ascorbic acid is a useful application, particularly when oxygen is limited. Copyright © 2004 John Wiley & Sons, Ltd.
Attenuating effect of a traditional korean formulation, Paeng‐Jo‐Yeon‐Nyeon‐Baek‐Ja‐In‐Hwan (PJBH), on hydrogen peroxide‐induced injury in PC12 cells
Authors: Koo Byung‐Soo , Kim Yeon‐Kye , Park Kyung‐Su , Chung Kang‐Hyun , Kim Cheorl‐Ho 
Published: July 2004

AbstractThe Paeng‐Jo‐Yeon‐Nyeon‐Baek‐Ja‐In‐Hwan (PJBH) prescription is a dried decoctum consisting of a mixture of 18 medicinal herbs that include Semen Biotae, Fructus Torilis seu cnidii, Fructus Rubi, Herba Dendrobii, Radix Morindae ofﬁcinalis, Cortex Eucommiae, Radix Aspragi, Radix Polygalae, Radix Dipsaci, Ramulus Cinnamomi, Rhizoma Acori graminei, Rhizoma Alismatis, Rhizoma Dioscoreae, Radix Ginseng, Radix Rehmanniae preparata, Fructus corni, Fructus Schisandrae and Herba Cistanches. The effect of PJBH extracts on H2O2‐induced toxicity in the rat pheochromocytoma line PC12 was examined by measurements of cell lesion, level of lipid peroxidation and antioxidant enzyme activities, since free radicals are involved in neurodegeneration in Alzheimer's disease (AD). After a 30 min exposure of the cells to H2O2 (150 µM), a marked decrease in cell survival, activities of glutathione peroxidase and catalase as well as an increased production of malondialdehyde (MDA) were found. Pretreatment of the cells with PJBH (0.5–10 µg/ml) prior to H2O2 exposure signiﬁcantly elevated cell survival, antioxidant enzyme activities and resulted in a decrease in the level of MDA. The effects of the PJBH on hydrogen peroxide‐induced injury in PC12 cells were also examined. PJBH had a remarkable elevating effect on catalase and GSH‐Px activities as well as cell survival, suggesting that cytoprotective effects of the PJBH are involved in stimulation against intermediate concentrations of H2O2‐induced PC12 cell injury. The above‐mentioned neuroprotective effects were also compared with the effect of tacrine. The results suggest that PJBH has potential for use as a novel neuronal therapeutic agent. Copyright © 2004 John Wiley & Sons, Ltd.
Methods to study the phytochemistry and bioactivity of essential oils
Authors: Lahlou Mouhssen 
Published: July 2004

AbstractMany essential oils are extracted, analysed and their main components are identiﬁed, characterised and then published without any biological testing whatsoever. Their useful biological activities can remain unknown for years. Yet, the search for these activities often increases our knowledge of the potential use of oils in therapeutics. Therefore, there is a real need for a simple, reliable and reproducible methods to study the bioactivity of essential oils and their constituents which can detect a broad spectrum of action or speciﬁc pharmacological activities in aromatic plants. These methods can then be employed by natural product chemists, pharmacologists and biologists to conduct their scientiﬁc research and to valorise natural products. Standardisation of some of these methods is therefore desirable to permit more comprehensive evaluation of plant oils, and greater comparability of the results obtained by different investigators. Copyright © 2004 John Wiley & Sons, Ltd.
Antifungal activity of actinomycetes from cuban soils
Authors: Iznaga Y. , Lemus M. , González L. , Garmendía L. , Nadal L. , Vallín C. 
Published: July 2004

AbstractThis study reports on the capacity of actinomycete strains isolated from Cuban soils to produce antifungal agents. The antimicrobial activities were determined by susceptibility disk assay methods. We isolated 563 different actinomycetes and 286 produced compounds with antifungal activity. Our screening method indicated the presence of many possible polyene macrolide antibiotics and the important antifungal activity in the soils rich in minerals. Copyright © 2004 John Wiley & Sons, Ltd.
Antibacterial activity of the Chinese traditional medicine, Zi Hua Di Ding
Authors: Xie Chen , Kokubun Tetsuo , Houghton Peter J. , Simmonds Monique S. J. 
Published: July 2004

AbstractThe antibacterial activity of extracts from species of plants used in the Chinese medicine, Zi Hua Di Ding (Viola yedoensis, V. prionantha, Corydalis bungeana and Gueldenstaedtia verna), was tested against Bacillus subtilis and Pseudomonas syringae using a bioautographic assay. The petroleum ether and ethyl acetate extracts of all four species of plants showed activity against both species of bacteria, whereas the methanol and aqueous methanol extracts were inactive. Three fractions from the petroleum ether extracts of V. yedoensis, V. prionantha and C. bungeana showed activity against B. subtilis at 6.25 µg/mL. Preliminary analysis of these active fractions indicates that they contain long chain carboxylic acids. Copyright © 2004 John Wiley & Sons, Ltd.
Measurement System Analysis for Bounded Ordinal Data
Authors: de Mast Jeroen , van Wieringen Wessel 
Published: July 2004

AbstractThe precision of a measurement system is the consistency across multiple measurements of the same object. This paper studies the evaluation of the precision of measurement systems that measure on a bounded ordinal scale. A bounded ordinal scale consists of a finite number of categories that have a specific order. Based on an inventory of methods for the evaluation of precision for other types of measurement scales, the article proposes two approaches. The first approach is based on a latent variable model and is a variant of the intraclass correlation method. The second approach is a non‐parametric approach, the results of which are, however, rather difficult to interpret. The approaches are illustrated with an artificial data set and an industrial data set. Copyright © 2004 John Wiley & Sons, Ltd.
Optimization of a Car Brake Prototype as a Consequence of Successful DOE Training
Authors: Marco Lluís , Tort‐Martorell Xavier , Cuadrado Juan A. , Pozueta Lourdes 
Published: July 2004

AbstractIn this article we discuss the importance of running a successful experiment while teaching design of experiments (DOE) to working engineers. A key aspect is to build engineer's confidence in DOE methodology and in their capabilities of using it, and this means keeping the content simple and developing a learning‐by‐doing experience. We cover several aspects of the course content and preparation, but the emphasis is in the preparation, follow up, roles of teachers and attendants, and the planning and steps followed in preparing and conducting the real experiment. A crucial aspect is making sure that the attendants recognize that they have gained valuable knowledge. A measure of the success of the approach suggested is that after the course and the real experiment associated with it were finished, Bosch's engineers have run several other experiments completely on their own. Even though a professional statistician may have done a better job, the use of the techniques were correct and the learning from the experiments was highly valuable. Copyright © 2004 John Wiley & Sons, Ltd.
Designing Phase I ―X Charts with Small Sample Sizes
Authors: Champ Charles W. , Jones L. Allison 
Published: July 2004

AbstractMethods are examined for obtaining probability limits for Phase I Shewhart ―X charts when the process mean and standard deviation are estimated. The design methods assume m independent random samples of size n will be taken periodically from a normally distributed process. It is shown that the joint distribution of the standardized subgroup means follows either an approximate or exact multivariate t distribution, depending on the standard deviation estimator used. The multivariate t distribution is used to define the probability limits for the Phase I ―X chart. Extensive simulation compares the performance of the proposed limits with other design procedures. Tables of design constants are given for $m&#60;20$, and simple procedures for obtaining design constants are given for $m\geq 20$. Copyright © 2004 John Wiley & Sons, Ltd.
Failure Mode Identification through Clustering Analysis
Authors: Arunajadai Srikesh G. , Uder Scott J. , Stone Robert B. , Tumer Irem Y. 
Published: July 2004

AbstractResearch has shown that nearly 80% of the costs and problems associated with product design are created during product development, and cost and quality are essentially designed into products during the conceptual design stage. Failure identification procedures (such as failure modes and effects analysis (FMEA), failure modes, effects and criticality analysis (FMECA) and fault tree analysis (FTA)) and design of experiments are currently being used for both quality control and for the detection of potential failure modes during the design stage or post‐product launch. Although all of these methods have their own advantages, they do not provide the designer with an indication of the predominant failures that should receive considerable attention while the product is being designed. The work presented here proposes a statistical clustering procedure to identify potential failures in the conceptual design stage. A functional approach, which hypothesizes that similarities exist between different failure modes based on the functionality of the product/component, is employed to identify failure modes. The various steps of the methodology are illustrated using a hypothetical design example. Copyright © 2004 John Wiley & Sons, Ltd.
Synthetic Approaches Towards Quinazolines, Quinazolinones and Quinazolinediones on Solid Phase
Authors: Vögtle Markus M. , Marzinzik Andreas L. 
Published: July 2004

AbstractQuinazolines are a pharmacologically very attractive class of compounds and have shown activity in various assays. Several successfully launched drugs are based on this scaffold. As a consequence, a more intensive exploitation in drug discovery by solid‐phase syntheses of quinazoline libraries has been initiated. A diverse array of combinatorial quinazoline syntheses have been published and an increasing effort is to be expected in the near future to provide more efficient solid phase approaches towards quinazolines, quinazolinones and quinazolinediones. This review summarizes the literature published until January 2004 describing methods for synthesis and modification of these compounds on solid phase.
Classical QSAR Modeling of CCR5 Receptor Binding Affinity of Substituted Benzylpyrazoles
Authors: Leonard J. Thomas , Roy Kunal 
Published: July 2004

AbstractCCR5 receptor binding affinity of a series of substituted benzylpyrazole derivatives was subjected to QSAR study using Fujita‐Ban type analysis and a mixed approach based on Hansch and Fujita‐Ban analyses. Apart from appropriate indicator variables encoding different group contributions, different physicochemical variables like hydrophobicity (π), electronic (Hammett σ) and steric (molar refractivity, STERIMOL values) parameters of phenyl ring substituents of the benzyl moiety of the compounds were used as predictor variables. Additionally, Wang‐Ford charges of the common atoms of the compounds calculated from molecular electrostatic potential surface of AM1 optimized geometries of the compounds and various topological parameters were used as additional descriptors. The variables for the multiple regression analyses were selected based on principal component factor analysis and generated equations were statistically validated using leave‐one‐out technique and predicting the binding affinities of test set compounds. The analysis explores the substitutional requirements of the phenyl nucleus of the benzylpyrazole moiety of the compounds for effective binding with CCR5 receptor.
Quantitative Structure–Micellization Relationship Study of Gemini Surfactants Using Genetic‐PLS and Genetic‐MLR
Authors: Absalan G. , Hemmateenejad B. , Soleimani M. , Akhond M. , Miri R. 
Published: July 2004

AbstractA Quantitative structure‐property relationship analysis had been applied to a set of gemini surfactants which were of special interest because of their roles in environmental samples. Modeling of the critical micelle concentrations (CMC) of 94 gemini surfactants as a function of their theoretically‐derived descriptors (i.e. topological indices) was established by means of multiple linear regression (MLR) and partial least squares (PLS) regression methods. The genetic algorithm was used to find a set of descriptors that resulted in the best‐fitted models. The results showed that both MLR (with 9 selected descriptors) and PLS (with 20 selected descriptors) methods could model the relationship between CMC of gemini surfactants and their topological descriptors perfectly. However, better results obtained by PLS regression. The stability and validity of models were tested by cross‐validation technique and by prediction of the response values for the prediction set. The average relative error of prediction for the best MLR and PLS models, was equal to 2.94 and 0.36, respectively. Also, the respective squares of correlation coefficients of these models were 0.979 and 0.985.
Quantitative Structure‐Activity Relationships of Streptococcus pneumoniae MurD Transition State Analogue Inhibitors
Authors: Kotnik Miha , Oblak Marko , Humljan Jan , Gobec Stanislav , Urleb Uros , Solmajer Tom 
Published: July 2004

AbstractQuantitative structure‐activity relationship (QSAR) studies on a set of Streptococcus pneumoniae MurD transition‐state inhibitors were performed, using a comprehensive set of molecular descriptors calculated by CODESSA software. Multiple and best multiple linear regressions were applied to generate models for predicting their inhibitory activity. The results (the best model had r2 = 0.8818, s2 = 0.0749, F = 87.04 and r$\rm{ {_{cv}^{2}}}$=0.8488) demonstrate the importance of hydrogen bonding and that a matching conformation of ligands for interaction with the enzyme active site is required.
Impact of neglecting p‐type spin–orbit coupling during electronic structure calculations on solids
Authors: Boettger Jonathan C. 
Published: July 2004

AbstractFully relativistic density functional theory electronic structure calculations for crystalline solids have become nearly commonplace. It has been demonstrated, however, that two of the more common methods used for such calculations produce spin–orbit coupling energies for p‐type orbitals that are numerically unstable. The source of the instability and methods for its mitigation are discussed here. In particular, a stabilization strategy suggested by Söderlind, the complete neglect of p‐type spin–orbit coupling, is tested for a prototypical p‐bonded metal, Pb, using the linear combinations of Gaussian‐type orbitals–fitting function method. The zero‐pressure lattice constant and bulk modulus are both insensitive to the p‐type spin–orbit coupling. The density of states and the fcc‐bcc structural energy difference, however, are shown to be significantly affected by p‐type spin–orbit coupling. The complete neglect of p‐type spin–orbit coupling approximation should not be used to determine structural phase transition pressures for materials in which the bonding has a strong p character. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Spectroscopic constants of H2 using Monte Carlo methods
Authors: Alexander S. A. , Coldwell R. L. 
Published: July 2004

AbstractWe have computed the spectroscopic constants we, wexe, αe, and Be of the ground state of H2 using two methods. In the first method, a highly accurate potential energy surface was generated using explicitly correlated wave functions and variational Monte Carlo techniques. We calculated the vibrational‐rotational energies from this surface and then obtained the spectroscopic constants by fitting these energies to a simple equation. In the second method, the spectroscopic constants were determined from local derivatives of the energy with respect to the internuclear distance. These derivatives have also been calculated using variational Monte Carlo techniques. For this system we find that the first method yields spectroscopic constants that are in excellent agreement with experiment. We also find that the second method, although slightly less accurate, is extremely well suited to Monte Carlo calculations. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Wave‐function‐based ab initio correlation treatment for the buckminsterfullerene C60
Authors: Paulus Beate 
Published: July 2004

AbstractFirst‐principle calculations for large extended systems such as the buckminsterfullerene C60 are mainly performed within density functional theory. They yield reasonable agreement with experiment, but wave‐function‐based correlations methods are preferable to obtain better insight into the correlation properties. Starting from a Hartree–Fock calculation for the solid, an incremental scheme relying on localized orbitals is developed for the correlation energy of C60. This many‐body expansion converges well with distance of localized bonds involved in the correlation methods and with order of increments. A detailed knowledge of the influence of the correlation effects on the binding and the bond alternation is achieved. Comparison with diamond, graphite, and polyacetylene is made. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
New methods for old Coulomb few‐body problems
Authors: Harris Frank E. , Frolov Alexei M. , Smith Vedene H. 
Published: July 2004

AbstractCoulomb problems involving three or four particles can advantageously be described using wavefunctions that explicitly involve all the interparticle distances. In what is known as the Hylleraas method, a set of Slater‐type orbitals for the electrons of an atom is augmented by linear (or in some cases higher powers) of the interelectron separation(s). An alternative approach, of particular value when all the particles have comparable masses, is to use a wavefunction containing exponentials in all the interparticle distances. This “exponential ansatz” is straightforward to implement when there are three particles but has only recently been implemented for four‐body systems. Integral evaluation is reviewed for both the exponential ansatz and the Hylleraas method, the treatment of general angular symmetry is discussed, and kinetic‐energy matrix elements are examined and related to simpler integrals. Some illustrative results for the positronium molecule (e+e−e+e−) are included. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Deductive molecular mechanics of sp3 nitrogen atom and its application to analysis of a QM/MM interface
Authors: Tchougréeff A. L. , Tokmachev A. M. 
Published: July 2004

AbstractThe antisymmetrized product of strictly localized geminals (APSLG) wave function is used to construct a mechanistic picture for the sp3 nitrogen atom. We previously showed 18 that the classical force fields for the sp3 carbon atom can be sequentially derived from the APSLG‐MINDO/3 method. Here we try to extend this approach. Special attention is given to the hybridization pattern for the nitrogen atom. Interpolation formulae for the inversion potential are obtained and the role of different physical contributions to the local geometry structure around nitrogen is elucidated. The results obtained are applied to construction of the junction in QM/MM hybrid procedures when a lone pair is assigned to the QM subsystem while three covalent bonds are considered to be a part of the MM subsystem. Changes in the hybridization due to QM/MM boundary are considered as a source of modification of the QM lone‐pair characteristic as well as of that of the MM force fields. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Formulation and numerical approach to molecular systems by the Green function method without Born–Oppenheimer approximation II: Nucleus–electron correlation
Authors: Ito T. , Yoshimoto T. , Ohta Y. , Kawabe H. , Nagao H. , Nishikawa K. 
Published: July 2004

AbstractWe present a nucleus–electron gas model to estimate the nucleus–electron correlation energy. The expression of the effective interaction between nucleus and electron in the framework of the random‐phase approximation is derived. We find that the attractive interaction between nucleus and electron can be shielded. The expression of the perturbation energy within the ladder approximation is also derived by some simplicities. We present a numerical procedure to calculate the correlation energy and the correlation potential between nucleus and electron and estimate the nucleus–electron correlation potential. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Application of spectral intensities through a model potential approach to the prediction of photodissociation rate constants of CFC molecules in the ionosphere
Authors: Martín I. , Mayor E. , Velasco A. M. 
Published: July 2004

AbstractAbsorption of high‐frequency radiation by chlorofluorocarbon (CFC) compounds in the ionosphere leads to their photoionization and photodissociation. Rydberg states are known to play an essential role in the initiation of photochemical processes. The photoabsorption intensities in both bound and continuous spectral regions, through all the allowed Rydberg channels, of two Freon molecules, have been first calculated. Then, through the use of the intensity data, photolysis rate constants corresponding to dissociation pathways in zones E and D of the ionosphere have been determined. An extension of the molecular quantum defect orbital approach has been used to supply these rate constants for the first time. Neither previous measurements nor theoretical calculations on these properties have, to our knowledge, been reported. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Balancing economic considerations and the rights of indigenous people. The Mapuche people of Chile
Authors: Newbold Jane 
Published: July 2004

AbstractNatural resources, principally minerals, agriculture and forestry, underpin the economic achievements of Chile. As a consequence of this, successive governments have had to develop policies that encourage growth while protecting the country's resources, heritage and biodiversity. A major challenge has been to redress historical injustices perpetrated against indigenous people plus resolving present day conflicts between these people and encroaching industries, particularly from the forestry and energy sectors. A balance is needed between the price paid for economic advancement and the destruction of indigenous people's cultural heritage. Conflicting government legislation has complicated the situation. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.