bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bronchodilatory effects of salbutamol, ipratropium bromide, and their combination: Double‐blind, placebo‐controlled crossover study in cystic fibrosis
Authors: Ziebach Rita , Pietsch‐Breitfeld Barbara , Bichler Matthias , Busch Andreas , Riethmüller Joachim , Stern Martin 
Published: August 2002

AbstractThe efficacy of inhaled sympathomimetic and anticholinergic agents on airway obstruction in cystic fibrosis (CF) has been proven in several studies. However, studies comparing combined therapy with monotherapy led to divergent results, probably due to different study designs, different dosages, and the small numbers of patients investigated. Therefore, we wanted to answer the question which inhalation has the best short term effect: a sympathomimetic or an anticholinergic agent, or the combination of both. We investigated 17 patients with CF on 4 successive days in the morning, using pulmonary function testing before and 30 min after inhalation. Each patient received aerosolized salbutamol (SB, maximum dose (max.) 2.5 mg), ipratropium bromide (IB, max. 0.5 mg), the combination of both, or placebo (normal saline) in a randomized, double‐blind crossover design.The mean forced expiratory volume in the first second improved significantly (adjusted P‐value < 0.017) after each treatment compared to placebo. Analysis of variance showed that SB and combination therapy with SB and IB were superior to IB alone, without significant difference between SB and combination therapy. Response of a patient to combined therapy was usually associated with response to SB. Long‐term efficacy and side effects of treatment with bronchodilators still remain to be investigated after this short term study.We conclude that in CF patients bronchodilator therapy with sympathomimetic agents is usually sufficient. Only in cases with proven additional benefit from inhalation by anticholinergics should combination therapy be recommended. Pediatr Pulmonol. 2001; 31:431–435. © 2001 Wiley‐Liss, Inc.
Fluctuations in ion pairs and their stabilities in proteins
Authors: Kumar Sandeep , Nussinov Ruth 
Published: August 2002

AbstractThis report investigates the effect of systemic protein conformational flexibility on the contribution of ion pairs to protein stability. Toward this goal, we use all NMR conformer ensembles in the Protein Data Bank (1) that contain at least 40 conformers, (2) whose functional form is monomeric, (3) that are nonredundant, and (4) that are large enough. We find 11 proteins adhering to these criteria. Within these proteins, we identify 22 ion pairs that are close enough to be classified as salt bridges. These are identified in the high‐resolution crystal structures of the respective proteins or in the minimized average structures (if the crystal structures are unavailable) or, if both are unavailable, in the “most representative” conformer of each of the ensembles. We next calculate the electrostatic contribution of each such ion pair in each of the conformers in the ensembles. This results in a comprehensive study of 1,201 ion pairs, which allows us to look for consistent trends in their electrostatic contributions to protein stability in large sets of conformers. We find that the contributions of ion pairs vary considerably among the conformers of each protein. The vast majority of the ion pairs interconvert between being stabilizing and destabilizing to the structure at least once in the ensembles. These fluctuations reflect the variabilities in the location of the ion pairing residues and in the geometric orientation of these residues, both with respect to each other, and with respect to other charged groups in the remainder of the protein. The higher crystallographic B‐factors for the respective side‐chains are consistent with these fluctuations. The major conclusion from this study is that salt bridges observed in crystal structure may break, and new salt bridges may be formed. Hence, the overall stabilizing (or, destabilizing) contribution of an ion pair is conformer population dependent. Proteins 2001;43:433–454. © 2001 Wiley‐Liss, Inc.
Anabaena apoflavodoxin hydrogen exchange: On the stable exchange core of the α/β(21345) flavodoxin‐like family
Authors: Langdon Grant M. , Jiménez M. Angeles , Genzor Carlos G. , Maldonado Susana , Sancho Javier , Rico Manuel 
Published: August 2002

AbstractAn important issue in modern protein biophysics is whether structurally homologous proteins share common stability and/or folding features. Flavodoxin is an archetypal α/β protein organized in three layers: a central β‐sheet (strand order 21345) flanked by helices 1 and 5 on one side and helices 2, 3, and 4 on the opposite side. The backbone internal dynamics of the apoflavodoxin from Anabaena is analyzed here by the hydrogen exchange method. The hydrogen exchange rates indicate that 46 amide protons, distributed throughout the structure of apoflavodoxin, exchange relatively slowly at pH 7.0 (kex < 10−1 min−1). According to their distribution in the structure, protein stability is highest on the β‐sheet, helix 4, and on the layer formed by helices 1 and 5. The exchange kinetics of Anabaena apoflavodoxin was compared with those of the apoflavodoxin from Azotobacter, with which it shares a 48% sequence identity, and with Che Y and cutinase, two other α/β (21345) proteins with no significant sequence homology with flavodoxins. Both similarities and differences are observed in the cores of these proteins. It is of interest that a cluster of a few structurally equivalent residues in the central β‐strands and in helix 5 is common to the cores. Proteins 2001;43:476–488. © 2001 Wiley‐Liss, Inc.
Uptake and translocation of carpropamid in rice (Oryza sativa L)
Authors: Rohilla Rashmi , Singh Uma S , Singh R L 
Published: August 2002

AbstractTranslocation of the antiblast compound, carpropamid, was investigated in rice using [14C]carpropamid. When applied to the seed, carpropamid was not only readily absorbed but was translocated to different parts of the seedlings emerging from treated seeds. A substantial portion of fungicide appeared to be exuded onto the leaf surface. In 21‐day‐old plants grown from [14C]carpropamid‐treated seeds, 27.2% of the radioactivity isolated from leaves was present on the surface of lamina. This exuded fraction is probably responsible for its action as a fungal anti‐penetrant compound. Following 30‐min root dipping of 14‐day‐old seedlings, carpropamid was rapidly absorbed and translocated throughout the seedling. Its intra‐laminar distribution was uniform as determined by autoradiography. Only a small fraction (<2%) of fungicide applied to the foliage was translocated beyond the site of application within the treated leaf. Translocation was primarily apoplastic. Approximately 54% of the radioactivity recovered from leaves was in the form of carpropamid. At least seven radiolabelled metabolic products were observed by TLC. Only 8.3% of radioactivity applied through the seeds could be recovered from 21‐day‐old seedlings.© 2001 Society of Chemical Industry
Modern structural wood products
Authors: Lam Frank 
Published: August 2002

Abstract A Correction has been published for this article in Progress in Structural Engineering and Materials 3(4) 2001, 361.Engineered wood products are structural composites that have been gaining successes in the construction industry. The mechanical and physical properties of these products depend on the interacting relationships between the quality of the resource, the manufacturing process, and the applications. In general their mechanical properties are more uniform compared with solid sawn material; hence, higher allowable properties are available in engineering design. This paper reviews the manufacturing processes, structural properties, physical attributes, and common applications of some of the major engineered wood products including: glued‐laminated timber, parallel strand lumber, laminated strand lumber, laminated veneer lumber, and thick oriented strand board/rimboard.
Chemoprotective potentials of homoisoflavonoids and chalcones of Dracaena cinnabari: modulations of drug‐metabolizing enzymes and antioxidant activity
Authors: Machala Miroslav , Kubínová Renata , Hořavová Pavla , Suchý Václav 
Published: August 2002

AbstractA series of homoisoflavonoids and chalcones, isolated from the endemic tropical plant Dracaena cinnabari Balf. (Agavaceae), were tested for their potential to inhibit cytochrome P4501A (CYP1A) enzymes and Fe‐enhanced in vitro peroxidation of microsomal lipids in C57B1/6 mouse liver. The effects of the polyphenolic compounds were compared with those of prototypal flavonoid modulators of CYP1A and the well‐known antioxidant, butylated hydroxytoluene. 2‐Hydroxychalcone and partly 4,6‐dihydroxychalcone were found to be strong inhibitors of CYP1A‐dependent 7‐ethoxyresorufin O‐deethylase (EROD) activity in vitro comparable to the effects of quercetin and chrysin. The first screening of flavonoids and chalcones of Dracaena cinnabari for antioxidant activity was done in an in vitro microsomal peroxidation assay. While chalcones were shown to be poor antioxidants, 7,8‐methylenedioxy‐3(4‐hydroxybenzyl) chromane, as one of the tested homoisoflavonoids, exhibited a strong antioxidant activity comparable to that of the strongest flavonol antioxidant, quercetin. Copyright © 2001 John Wiley & Sons, Ltd.
Hepatoprotective action of an oleanolic acid‐enriched extract of Ligustrum lucidum fruits is mediated through an enhancement on hepatic glutathione regeneration capacity in mice
Authors: Yim T. K. , Wu W. K. , Pak W. F. , Ko K. M. 
Published: August 2002

AbstractThe fruits of Ligustrum lucidum Ait. (FLL) were fractionated into petroleum ether (FLL‐Pe), chloroform (FLL‐Ch), butanol (FLL‐Bu) and aqueous (FLL‐Aq) fractions, of which FLL‐Ch and FLL‐Bu were found to be enriched with oleanolic acid (OLA). The in vivo antioxidant activities of various FLL fractions and OLA were assessed by examining the effect on carbon tetrachloride (CCl4)‐induced hepatotoxicity in mice. Pretreatment of animals with various FLL fractions could protect against CCl4‐induced hepatotoxicity to a varying degree, with OLA‐enriched FLL‐Bu and FLL‐Ch being more potent. However, a mortality rate of 60% was observed in the FLL‐Ch pretreated and CCl4‐intoxicated mice. OLA pretreatment also produced a dose‐dependent protection against CCl4 hepatotoxicity. The hepatoprotection afforded by FLL‐Bu or OLA pretreatment was associated with an enhancement of hepatic­glutathione regeneration capacity (GRC). In contrast, the inability of FLL‐Aq pretreatment to enhance hepatic GRC resulted in a failure to prevent CCl4‐induced hepatic injury. The results suggest that the hepatoprotective action afforded by OLA‐enriched FLL‐Bu or OLA pretreatment may be mainly mediated by the enhancement of hepatic GRC, particularly under conditions of CCl4‐induced oxidative stress. Copyright © 2001 John Wiley & Sons, Ltd.
Pycnogenol® efficacy in the treatment of systemic lupus erythematosus patients
Authors: Stefanescu M. , Matache C. , Onu A. , Tanaseanu S. , Dragomir C. , Constantinescu I. , Schönlau F. , Rohdewald P. , Szegli G. 
Published: August 2002

AbstractA pilot study was performed to evaluate the efficacy of Pycnogenol® treatment in systemic lupus erythematosus (SLE) patients. Eleven SLE patients were treated with first line medication according to disease activity and in addition, six of them received Pycnogenol® and five a placebo. The SLE disease activity index (SLEDAI), serum anti‐dsDNA antibodies, fibrinogen, C‐reactive protein levels, erythrocyte sedimentation rate, production of reactive oxygen species (ROS) by neutrophils, spontaneous apoptosis and p56lckspecific activity in peripheral blood lymphocytes were evaluated. Pycnogenol® treatment determined a significant reduction of ROS production, apoptosis, p56lckspecific activity and erythrocyte sedimentation rate. In addition, the decrease of SLEDAI was significant in the Pycnogenol® treated group compared with the placebo group (p= 0.018). The results obtained suggest that Pycnogenol® could be useful for second line therapy to reduce the inflammatory feature of SLE. Copyright © 2001 John WIley & Sons, Ltd.
Semiempirical INDO/S study on the solvatochromism of merocyanine dyes
Authors: Bicca de Alencastro Ricardo , Da Motta Neto Joaquim Delphino 
Published: August 2002

AbstractWe report results of semiempirical intermediate neglect of differential overlap (INDO/S) calculations on the spectroscopy of 4′‐hydroxy‐1‐methylstilbazolium betaine (HMSBB). Solvent effects were included using both the continuum and supermolecule approaches. The calculated spectra are compared with experimental ultraviolet‐visible spectra for several solvents. The odd bathochromic shift of the low energy band (for nonpolar solvents) is tentatively discussed in terms of the contributions of different solvation mechanisms, and an assignment based on INDO/S calculated spectra is presented. We start from the assumption that in solution, conformations other than the completely planar structure (A) are possible. For protic solvents, in which hydrogen bonding constitutes the main contribution to solvation, calculations using the planar, fully optimized AM1 geometry reproduce fairly well the observed spectra. The intense, π→π* band is calculated close to 20,000 cm−1, in good agreement with the experimental values in water and methanol. For the very polar formamide, the INDO/S+SCRF result is also very accurate, suggesting that formamide's strong polarity induces HMSBB to adopt the planar structure A. For polar solvents with nonspecific interactions such as acetonitrile or dimethylformamide, the situation is not as clear. We speculate that the experimental numbers can be reproduced only by a very large supermolecule. Finally, for nonpolar solvents such as cyclohexane, benzene and CCl4, the experimental number of 16,141 cm−1 (previously obtained from extrapolation of solvent mixtures by Jacques and coworkers) is reproduced by the INDO/S method only considering structures B and C. These results can be considered a confirmation of Jacques' suggestion that the solvatochromism of HMSBB can be explained by the solvents inducing a geometry change in HMSBB. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Excited states of Na and Al iso‐electronic ions: Symmetry adapted cluster–configuration interaction study
Authors: Das A. K. , Ehara M. , Nakatsuji H. 
Published: August 2002

AbstractThe Rydberg excited levels of s, p, d, and f symmetries are studied up to principal quantum number n=5 for the first eight members of the Na iso‐electronic sequence (Na to Ar7+) and for the first six members of the Al iso‐electronic sequence (Al to Ar5+) by the symmetry adapted cluster–configuration interaction (SAC–CI) method. The valence Slater‐type orbital (STO) basis sets of Clementi et al. and the optimized Rydberg STO functions are used by the STO‐6G expansion method. The calculated transition energies agree well with the experimental values wherever available. The results for the 4f level of S3+ and for the 5s, 4p, 5p, and 4f levels of Cl4+ and Ar5+ are predicted for the first time. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Solvable quartic potentials and their isospectral partners
Authors: Peña J. J. , Ovando G. , Morales‐Guzmán D. , Morales J. 
Published: August 2002

AbstractIn this work, we present an operational method based on the use of supersymmetry applied to quantum mechanics, shape invariance, and intertwining techniques to determine certain classes of solvable potentials. Our proposal uses an ansatz which matches the Witten superpotential, allowing us to identify, through a particular Ricatti relationship, the potentials that are solvable as well as to obtain straightforwardly the corresponding ground state eigenvalues, energy, and wave function. As a useful application of the proposed method, we obtain some examples of solvable quartic potentials as well as, with the aid of the standard and generalized Darboux transform, the partner isospectral potentials that are associated with the models under consideration. The method can be easily extended and used to find new solvable potentials which could be useful in the modeling of specific quantum interactions. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Density functional study of the structural, electronic, and magnetic properties of neutral and charged rhodium clusters up to tetramer
Authors: Lacaze‐Dufour Corinne , Mineva Tzonka , Russo Nino 
Published: August 2002

AbstractModel core potential computations were performed for Rh2, Rh3, and Rh4 clusters and their respective cations and anions using the linear combination of Gaussian‐type orbital, nonlocal spin density method. The optimized geometries, electronic and magnetic structures, binding and fragmentation energies, adiabatic ionization potentials, and electron affinities were determined. Results show that the ionization potentials, electron affinities, binding energies, and magnetic moments decrease with the cluster size. For Rh2 and Rh3 the most stable structures exhibit ferromagnetic properties, while Rh4 in its ground state is found to be paramagnetic. The structures of minimum energy for the charged species often differs from the corresponding neutral one. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Generalized spin density functional theory for noncollinear molecular magnetism II—Influence of gradient correction and self‐interaction correction
Authors: Yamanaka S. , Yamaki D. , Kiribayashi S. , Yamaguchi K. 
Published: August 2002

AbstractWe have implemented generalized spin orbital (GSO) based localized spin density approximation (LSDA) and general gradient approximation (GGA) calculations for noncollinear magnetic systems. Further self‐interaction correction (SIC) within a perturbational scheme is applied for the GSO solutions of LSDA and GGA. The Boys localization is employed to obtain appropriate SIC orbitals. The calculational results are compared with those of generalized Hartree–Fock (GHF) methods and full configuration interaction (FCI). From our calculations of equilateral and isosceles triangular H3 molecule, it was found that SIC improves significantly the feature of potential surface as well as the total energy values. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Optical spectroscopy of (C2H5NH3)2CdCl4:Cu2+ under pressure: Study of Cu2+ local structure from theoretical calculations
Authors: Valiente R. , Rodríguez F. , Aramburu J. A. , Moreno M. , Barriuso M. T. , Sousa C. , de Graaf C. 
Published: August 2002

AbstractThe variations experienced by the energy Eu(π) of the eu(π)→b1g (∼x2–y2) charge‐transfer transition of (C2H5NH3)2CdCl4:Cu2+ upon pressure in the 0‐ to 40‐kbar range have been measured at room temperature by means of a sapphire anvil cell. These data reveal that Eu(π) undergoes a red shift of 1400 cm−1 on passing from ambient pressure to 40 kbars. To understand this puzzling result theoretical calculations of ∂Eu(π)/∂Req and ∂Eu(π)/∂Rax have been performed where Req and Rax mean the equatorial and axial Cu2+–Cl− distances of the elongated CuCl64− complex, respectively. All results indicate that ∂Eu(π)/∂Req and ∂Eu(π)/∂Rax for Req=228 pm and Rax=297 pm are indeed negative. Moreover ab initio complete active space self‐consistent field (CASSCF/CASPT2) and density functional calculations lead to ∂Eu(π)/∂Rax values, which are about 10 times smaller than those of ∂Eu(π)/∂Req. From the ensemble of experimental and theoretical results, it is concluded that a pressure of 40 kbars gives rise to a decrement of ≈25 pm of the axial distance and at the same time to an increase of ≈7 pm of the equatorial one. It is stressed that the present study on a diluted Jahn–Teller impurity lies far beyond the current possibilities of X‐ray absorption structure techniques. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Ab initio calculation and quasi‐classical dynamics study of the two lowest potential energy surfaces of the O(1D)+HBr system*
Authors: Hernández María Luz , Alvariño José María , Laganà Antonio , Rosi Marzio , Sgamellotti Antonio 
Published: August 2002

AbstractThe lowest singlet 11A′ and 11A″ potential energy surfaces (PES) of the O(1D)+HBr system have been ab initio computed. The complete active space self‐consistent field (CASSCF) method was used in most of the calculations, considering all the valence orbitals as active. The calculations were complemented with both analytical gradient calculations to characterize the stationary points and multireference configuration interaction (MRCI) calculations at selected nuclear geometries to improve the determination of the barrier heights and of the energetics. Electronic energy values for both PESs were then independently fitted by polynomial expansions in bond order coordinates. On the fitted surfaces quasi‐classical trajectories were separately run. Single‐surface calculations behave qualitatively different for the ground and the excited PES at low collision energies. A satisfactory agreement with existing experimental data was obtained by using the ground PES while calculations performed on the excited 11A″ PES worsened the agreement. However, when collision energy is increased, detailed experimental distributions are less well reproduced by calculations on the ground PES. This may imply the participation via nonadiabatic transitions of the 21A′ PES at higher energies while the adiabatic ground singlet PES well describes reactive scattering at low collision energy. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
High‐level ab initio study of the N+(3P)+SH2reactions in the gas phase: Role of spin‐forbidden pathways
Authors: Ijjaali Fatima , Alcamí Manuel , Mó Otilia , Yáñez Manuel 
Published: August 2002

AbstractThe singlet and triplet potential energy surfaces involved in N++SH2reactions have been explored using high‐level ab initio techniques. The geometries of the stationary points were optimized at the QCISD/6‐311G(df,p) level. The final energies were obtained in CCSD(T)/6‐311+G(3df,2p) single‐point calculations. The results obtained show that, although the N+(1D)+SH2entrance channel is higher in energy than the N+(3P)+SH2one, most of the [H2, S, N]+singlet state cations are lower in energy than the corresponding triplets, due to their different bonding characteristics. Both singlet and triplet potential energy surfaces are quite close each other, and crossover between them can occur. The minimum energy crossing points were located by means of CASSCF(6,5) calculations. The spin‐orbit couplings show that the transition probability from the triplet to the singlet potential energy surface is significantly large. One of the most important consequences is that some of the products of the reaction, such as SH+, can be formed in typical spin‐forbidden processes. Since all the relevant structures along these pathways are much lower in energy than the reactants, this mechanism should be accessible even at low impact energies and therefore could be important in processes taking place in interstellar media. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Flexible open‐cell design for internal‐source matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry
Authors: Frankevich Vladimir , Zenobi Renato 
Published: August 2002

AbstractA new Fourier transform ion cyclotron resonance (FTICR) cell design is described that improves the performance of internal‐source matrix‐assisted laser desorption/ionization (MALDI) applications. The design employs a capacitively coupled open FTICR cell and a ring electrode placed between the ion source and the ICR cell. The flexibility of our open‐cell design allows the use of several different trapping schemes for ion detection. Elimination of the drift time dependence in a MALDI experiment, ion accumulation, RF ion selection, and improved trapping of MALDI ions desorbed at an angle to the surface normal are some of the advantages of this design. Copyright © 2001 John Wiley & Sons, Ltd.