bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recurrent unilateral bacterial pneumonias and interstitial fibrosis associated with pulmonary vein atresia: Successful treatment with endovascular stent implantation
Authors: Sacco O. , Fregonese B. , Fregonese L. , Gambini C. , Pongiglione G. , Rossi G.A. 
Published: October 2002

AbstractA variety of pulmonary vascular disorders, such as hemangiomatosis, telangectasia, and veno‐occlusive disease, may be involved in the pathogenesis of interstitial lung diseases. We describe the case of a girl with recurrent bacterial pneumonia and progressive interstitial fibrosis affecting the right lung. Morphologic evaluation of the lung biopsy showed structural changes of the vessel walls suggesting pulmonary hypertension. The echocardiogram showed the presence of centripetal blood flow in the right pulmonary artery from the periphery of the lung to the heart. A selective right angiography demonstrated the presence of pulmonary venous obstruction at the veno‐atrial junction, successfully treated by endovascular stent implantation during cardiac catheterization. Pediatr Pulmonol. 2002; 34:324–328. © 2002 Wiley‐Liss, Inc.
Gavaging the infant lung
Authors: Avital Avraham , Godfrey Simon , Bortz Raphael , Uwyyed Kamal , Springer Chaim 
Published: October 2002

AbstractAn 8‐month‐old female infant was hospitalized for persistent bilateral infiltrates, failure to thrive, and tachypnea. An extensive diagnostic workup was negative, except for strong oil‐red O staining of the white‐turbid bronchoalveolar lavage fluid and borderline esophageal pH monitoring. Conservative treatment failed, and she was scheduled for gastrostomy and Nissen‐fundoplication until the family physician found that the anxious mother was feeding the child forcibly, which caused chronic aspiration pneumonitis. The mother was given psychological support and was supervised, and the child recovered completely. Pediatr Pulmonol. 2002; 34:388–390. © 2002 Wiley‐Liss, Inc.
Within‐ and between‐day variability of respiratory impedance, using impulse oscillometry in adolescent asthmatics
Authors: Goldman Michael D. , Carter Rick , Klein Robert , Fritz Greg , Carter Brian , Pachucki Paul 
Published: October 2002

AbstractThe objectives of the present study were to: 1) assess spirometric indices and respiratory impedance with forced oscillation (FO), using impulse oscillometry (IOS) in clinically stable asthmatic children over 3 consecutive days; 2) assess FO reactance (X), using an integrated index and resistance (R) separately during inspiration and expiration; and 3) assess effects on FO of hand support of cheeks vs. no hand support. Our hypotheses were: 1) because of increased sensitivity, IOS manifests day‐to‐day variability not demonstrable by spirometry; 2) IOS R during expiration exceeds that during inspiration; and 3) hand support of cheeks affects IOS R and X only minimally. We obtained triplicate twice‐daily measures of IOS R and X in asthmatic adolescents at summer camp, in a convenience sample of children willing, with parental permission, to undergo repeated testing on consecutive days. Subjects received all medications between 6:30–7:30 AM, and were bronchodilated at time of testing. Subjects underwent IOS tests without hand support of cheeks, followed by tests with both hands supporting cheeks. ANOVA and regression analyses were used to discern technique differences.Significant differences in IOS inspiratory R5, R5 − R15 (frequency dependence of R), and low frequency reactance area (AX) occurred across 3 days, but spirometric indices were unchanged. Inspiratory R at 5 Hz (R5) was significantly smaller than expiratory R5 (P < 0.0001). ANOVA revealed no significant differences between hand and facial muscle cheek support for IOS R and X below 15 Hz, but significant differences occurred above 15 Hz.In conclusion, inspiratory R5, R5 − R15, and AX are sensitive measures for detecting changes in bronchomotor tone in adolescent asthmatic subjects, while expiratory R5 may be influenced by additional factors. Manual support of cheeks does not appear to affect IOS indices of peripheral airway obstruction in adolescent asthmatics. IOS is a practical method for quantifying respiratory mechanics, and its potential role in disease management warrants further study. Pediatr Pulmonol. 2002; 34:312–319. © 2002 Wiley‐Liss, Inc.
Protein folding in mode space: A collective coordinate approach to structure prediction
Authors: Abseher Roger , Nilges Michael 
Published: October 2002

AbstractDoes the dynamics of a protein encode its structure? Many studies have adressed the inverse of this question—how a three‐dimensional structure determines its dynamics—using molecular dynamics simulation, normal mode analysis, and similar methods. Recently we have developed a molecular dynamics (MD) simulation method to impose dynamic properties on ensembles of MD trajectories in the form of restraints on structural diversity in the directions of the principal components of motion of the molecule. In the current work, we investigate if these restraints in combination with a standard MD force field are sufficient to generate native structure in disordered structural ensembles. We present simulations from a series of increasingly disordered structural ensembles obtained by thermal unfolding or randomization of the coordinates of the native structure of two src‐homology 3 (SH3) domains. Native structure formation is observed under the sole action of the diversity restraint and the MD force field. We investigate the importance of accuracy of the description of native dynamics. Protein folding is a highly cooperative process. The dynamic restraints may enforce long‐range cooperativity and thus speed up the folding from unstructured states. Applications of the restraints to structure refinement and structure prediction are possible. Proteins 2002;49:365–377. © 2002 Wiley‐Liss, Inc.
Optimal potentials for predicting inter‐helical packing in transmembrane proteins
Authors: Dobbs H. , Orlandini E. , Bonaccini R. , Seno F. 
Published: October 2002

AbstractA set of pairwise contact potentials between amino acid residues in transmembrane helices was determined from the known native structure of the transmembrane protein (TMP) bacteriorhodopsin by the method of perceptron learning, using Monte Carlo dynamics to generate suitable “decoy” structures. The procedure of finding these decoys is simpler than for globular proteins, since it is reasonable to assume that helices behave as independent, stable objects and, therefore, the search in the conformational space is greatly reduced. With the learnt potentials, the association of the helices in bacteriorhodopsin was successfully simulated. The folding of a second TMP (the helix‐dimer glycophorin A) was then accomplished with only a refinement of the potentials from a small number of decoys. Proteins 2002;49:342–349. © 2002 Wiley‐Liss, Inc.
(+)‐tiliarine, a selective in vitro inhibitor of human melanoma cells
Authors: Seal Tapan , Mukherjee Biswapati 
Published: October 2002

AbstractFive diphenylbisbenzylisoquinoline (DBBI) alkaloids, tiliacorinine, tiliacorine, nor‐ tiliacorinine A, tiliarine and tiliamosine were isolated from the ethanol extract of the roots of Tiliacora racemosa Colebr. and identified by spectral techniques. Of these (+)‐tiliarine is the only one which exhibited a selective inhibitory effect against human melanoma cells (G 361) and had no activity on normal human fibroblasts (CCD 974 SK). The activity of (+)‐tiliarine against the human melanoma cell line was not much modified in the presence of calcium chloride. Copyright © 2002 John Wiley & Sons, Ltd.
Exchange contributions in the electronic structure of systems with 1D‐periodicity: Importance and computation
Authors: Delhalle Joseph , Fripiat Joseph G. , Harris Frank E. 
Published: October 2002

AbstractThe purpose of this article is to point out to the scientific community interested in Hartree–Fock ab initio calculations that accurate calculations of the exchange contributions are essential. An extremely simple system such as the infinite chain of Be atoms, (‐Be‐)∞, treated in direct space at the RHF level with the 3‐21G basis fails to converge to physically meaningful results. An analysis based on the convergence properties of finite Fourier series points to the exchange contributions as the source of the problem. Owing to its capability of handling with the necessary accuracy all lattice summations, including the exchange sums, the Fourier representation is able to treat the problem effectively and is confirmed as a procedure of choice for RHF electronic structure calculations of systems with 1D periodicity. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
A graph theoretical characterization of proteomics maps
Authors: Randić Milan 
Published: October 2002

AbstractWe consider the numerical characterization of proteomics maps based on graph theoretical invariants. A graph is associated with a map using partial ordering of map spots. From graph constructed in this way, one can extract several graph theoretical invariants. In addition, one can embed the derived graph directly over the map and characterize it by invariants of an accompanying distance matrix. Finally, we introduce an in‐between characterization of a map based on the distance‐adjacency matrix in which only distances between adjacent vertices (spots) of embedded graph are considered. The advantage of such an approach follows from the fact that the distance‐adjacency matrix is a sparse matrix which is computationally less intensive. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Mutual conversion of three flavors of Gaussian type orbitals
Authors: Mathar Richard J. 
Published: October 2002

AbstractMutual expansion formulas are developed for three types of Gaussian orbitals: Hermite Gaussians, Cartesian Gaussians, and spherical Gaussians. Overlap, kinetic energy, and Coulomb energy matrix elements are presented for generalized spherical basis functions proportional to \documentclass{article}\pagestyle{empty}\begin{document}$r^{n+s}\exp(-\alpha r^{2})Y^{m}_{n}(\hat{\mathbf{r}})$\end{document} where \documentclass{article}\pagestyle{empty}\begin{document}$Y^{m}_{n}$\end{document} represents spherical harmonics, where −n≤m≤n, and where s=0,2,4,… . Hartree–Fock benchmark calculations on isolated, neutral 2He, 6C, and 12Mg atoms indicate that inclusion of the s≥2 generalized functions is slightly unfavorable if the electronic ground state energy is to be minimized. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Density functional study on geometry and electronic structure of nitrile hydratase active site model
Authors: Nowak W. , Ohtsuka Y. , Hasegawa J. , Nakatsuji H. 
Published: October 2002

AbstractNitrile Hydratase (R. Sp. 771, NHase, EC. 4.2.1.84, CAS registration no. 82391‐37‐5), the enzyme that plays an important role in the industrial production of acrylamide, is studied theoretically in this article. For the first time the electronic structure of the active site of nitrosylated form with a proper oxidation state of the cysteine ligands is calculated using the density functional theory (DFT) method with the Becke, Lee, Yang, and Paar (B3LYP)6‐31G* functional. The optimized geometries of six and five coordinated complexes are different, showing that the photodissociation of NO triggers a substantial relaxation of the NHase active site. The major structural change is a shift of the position of iron with respect to the four equatorial ligands, which resembles a heme doming observed in myoglobins. Calculated charge distribution supports the role of Fe as a possible Lewis acid in catalytic cycle. We found that the cysteine‐sulfinic residue (Cys112) is very strongly polarized in NHase. Sulfur atom Sγ Cys112 is predicted to be the most positively charged center. This result gives independent support to a very recent finding of the critical role of an oxidation in the position Cys112 for preserving catalytic activity of the enzyme (Endo, I.; Nojiri, M.; Tsujimura, M.; Nakasako, M.; Nagashima, S.; Yohda, M.; Odaka, M. J Inorgan Biochem 2001, 83, 247). © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Quantum molecular modeling of quercetin—Simulation of the interaction with the free radical t‐BuOO⋅*
Authors: Vasilescu D. , Girma R. 
Published: October 2002

AbstractQuercetin is one of the most potent antioxidants belonging to the flavonoids, which are a naturally occurring family of molecules. The optimized forms of the 3′‐, 4′‐, 3‐, 5‐, and 7‐quercetin radicals were computed using ab initio procedure at the 6‐31G* level. We have deduced that the 3′‐, 4′‐, and 3‐radicals are the most energetically favored. The simulation of the H abstraction at the 4′‐hydroxyl of quercetin by the free radical t‐BuOO⋅ (tert‐butyl peroxyl) was conducted using the supermolecular model composed of quercetin in interaction with t‐BuOO⋅. The mechanism of the scavenging of the free radical by quercetin is discussed on the basis of various AM1 and ab initio (level 6‐31G*) quantum molecular computations and the obtained frontier orbitals and total spin density. The analysis of the spin density around the obtained free radical 4′‐quercetin indicates that the major density of spin α(↑) is concentrated in the B ring on the O4′ oxygen; we observe also a slight delocalization of spins α(↑) and β(↓) on the B ring and on a part of the C ring. In conclusion, the antioxidant power of quercetin may be associated mainly with the B ring and a half of the C ring. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Some observations on P.‐O. Löwdin's definition of a molecule
Authors: Sutcliffe Brian 
Published: October 2002

AbstractIn a talk given in 1986 in honor of Prof. Raymond Daudel, Löwdin famously defined a molecule in the following quantum mechanical terms: “A system of electrons and atomic nuclei is said to form a molecule if the Coulombic Hamiltonian H′—with the centre of mass motion removed—has a discrete ground state energy E0.” We examine this definition in the context of chemical thinking about a molecule and attempt to place it in the context of the developments since the time of that talk. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
A note suggesting an approximation for the Hohenberg and Kohn functional*
Authors: Massa Lou 
Published: October 2002

AbstractAn approximation is given for calculation of the Hohenberg and Kohn (HK) functional. This follows from reduced density matrices which are functionals of the experimental electron density, obtained from X‐ray scattering, Clinton's equations, and conditions for N‐representability by correlated‐determinant wave functions. As these wave functions are known to be of accurate form, an analogous degree of accuracy is expected for the HK functional approximation which flows from them. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Valence states of the cyano radical Feynman's way
Authors: Sorensen Thomas E. , England Walter B. 
Published: October 2002

AbstractScaled Feynman diagrams are proposed as perturbative corrections to the total energy. The proposal is tested by calculating potential energy curves for the valence states of the cyano radical. Unique features of the valence state are part of the starting approximation. The latter is computed with a standard quantum chemical method. For a particular method, the scale is independent of the valence state. At each bond distance, one set of quasiparticles and Feynman diagrams is used for all valence states. Scaling will be useful whenever perturbative corrections can be expressed with Feynman diagrams. In the cyano radical, competition for the odd electron between the σ and π orbitals produces a variety of valence states. Many are quasidegenerate. The 16 states investigated here are doublets and quartets with triple bonds, double bonds, ‘resonance’ bonds, bonds intermediate to double and triple bonds, and bonds intermediate to single and double bonds. Energy curves and spectroscopic constants are reported for the lowest lying quartets and two or more lowest doublets of Σ±, Π, and Δ symmetries, and also 12Φ symmetry. Inner and outer minima in the energy curve for 32Π are assigned to H and G, respectively. A more accurate assignment of a4Σ+ is made. Relative to experiment, maximum (average) errors in bond distance, frequency, and the adiabatic excitation energy are 1.6 pm (1 pm), 60 cm−1 (50 cm−1), and 19 kJ/mol (5 kJ/mol), respectively. The error in the ground state dissociation energy is 11 kJ/mol. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
An examination of substituent effects on the stabilization of a silicon–selenium double bond
Authors: Liao Hsin‐Yi , Su Ming‐Der , Chu San‐Yan 
Published: October 2002

AbstractSubstituent effects on the potential energy surface of X2SiSe (X=H, F, Cl, Br, SiH3, and CH3) were investigated by using the B3LYP and QCISD(T) methods. Our theoretical findings suggest that either electronegative or steric effects play a dominant role in determining the relative stability of X2SiSe and XSi–SeX. That is to say, our model calculations indicate that both dihalogen and dibulky substituted silaneselones are more stable than their isomeric silylene species thermodynamically and kinetically. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Important fluctuation dynamics of large protein structures are preserved upon coarse‐grained renormalization*
Authors: Doruker Pemra , Jernigan Robert L. , Navizet Isabelle , Hernandez Rigoberto 
Published: October 2002

AbstractThe fluctuations and important motions of three large proteins—hemaglutinin, xanthine dehydrogenase, and β‐galactosidase—have been considered with a range of models having various levels of detail to represent the structures. Because the slowest modes of motion are the largest contributors to the total motions, and because these motions depend mainly on the shapes of the structures rather than their details, it is possible to replace the real structures with significantly fewer points and still retain the essential features of the structure for these modes of motion. We obtain excellent results, both for the magnitudes of the individual motions as well as for the molecular changes occurring during these motions. Similar results are obtained with another completely different approach where the coarse graining is based on invariant regions of structure found by comparing two structures of the same protein, given as an example here for myosin. Results confirm the important coupling of local functional motions with the large‐scale motions, implying important functional roles for the entire protein structure. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Prediction of the existence of radon carbonyl: RnCO
Authors: Malli Gulzari L. 
Published: October 2002

AbstractOur ab initio all‐electron relativistic Dirac–Fock (DF) and nonrelativistic (NR) Hartree–Fock (HF) limit self‐consistent field molecular calculations predict the existence of radon carbonyl RnCO with the predicted dissociation energy of 4.81 and 4.22 eV, respectively. The calculations were performed for the linear RnCO at Rn–C and C–O bond distances of 2.38 and 1.12 Å, respectively. The relativistic DF dissociation (atomization) energy of the cation RnCO+ is, however, calculated to be 6.31 eV, indicating thereby that the highest occupied molecular spinor of RnCO is an antibonding molecular spinor. The ionization potential of RnCO calculated with our relativistic DF and NR HF wavefunctions is 7.73 and 7.99 eV, respectively. Mulliken population analysis of our relativistic DF (NR HF) wavefunction for RnCO yields population on C and O of −0.26 and +0.31 (−0.39 and −0.08), respectively. The bond dissociation energy of Rn–CO is calculated to be ∼28 kcal/mol. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Differences between the CO and NO properties for stability of alkali metal complexes Me(XO)n+, X=C or N
Authors: Larin Alexander V. , Trubnikov Dmitrii N. , Vercauteren Daniel P. 
Published: October 2002

AbstractThe influence of electron density redistribution upon vibrational excitation ν←0 on the interaction energy between CO and the metal atom Me in Me(CO)n+ carbonyls, n=1–3, is discussed. It is shown that the decrease of the CO dipole in the carbonyls upon vibrational excitation is qualitatively similar to the one of CO in the gas state. The respective decrease of the total energy of carbonyl complexes mainly due to the electrostatic repulsion Me+–C+O− (ν>6) is estimated herein for positively charged carbonyl complexes with Me=Li, Na, K, or Rb, upon the proposition of a strong coupling between the CO vibration and the electronic excitation of the whole complex. The difference between the NO and CO ligands with respect to their vibrational excitation is discussed. Also the appearance of angular bicarbonyls in adsorbed state in zeolite frameworks is considered. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Liquid chromatography/tandem mass spectrometry for the determination of fluoxetine and its main active metabolite norfluoxetine in human plasma with deuterated fluoxetine as internal standard
Authors: Li Chuan , Ji Zhouhua , Nan Fajun , Shao Qingxiang , Liu Ping , Dai Jieyu , Zhen Jiang , Yuan Hao , Xu Fang , Cui Jian , Huang Bin , Zhang Meiyun , Yu Cheng 
Published: October 2002

AbstractFluoxetine (F) and its N‐demehylated metabolite norfluoxetine (NF) are selective inhibitors of serotonin reuptake in humans. A new sensitive rapid method for the simultaneous determination of F and NF in plasma was established and validated, and was further applied to assess the bioequivalence of two oral formulations of F in 22 healthy Chinese male volunteers who received a single oral dose of each formulation (containing 20 mg of fluoxetine hydrochloride). The new method involves using liquid chromatography/tandem mass spectrometry (LC/MS/MS) in multiple reaction monitoring mode with deuterated fluoxetine (DF) as internal standard. High levels of analytical sensitivity and specificity of MS/MS detection enabled use of a simple liquid‐liquid extraction procedure. The combination of a simple sample clean‐up procedure and short chromatographic run‐time (5 min) considerably increased the productivity of the analytical method. The method was validated for the plasma concentration range 0.27–22 ng/mL for both of the test compounds, and the calibration curves were linear with coefficients of correlation >0.999. The limit of detection was 0.1 ng/mL for plasma F and NF. Taking the plasma sample size (200 µL) into account the new method for determination of F and NF is more sensitive than those described previously. Copyright © 2002 John Wiley & Sons, Ltd.