bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic resonance imaging of the coronary vessel wall at 3 T using an obliquely oriented reinversion slab with adiabatic pulses
Authors: Priest Andrew N. , Bansmann P. Martin , Kaul Michael G. , Stork Alexander , Adam Gerhard
Published: October 2005

Three‐dimensional methods offer volumetric coverage in coronary vessel wall imaging, in addition to high signal‐to‐noise ratios (SNR). To increase SNR further, it is desirable to implement such 3D methods at 3 T. At this field strength, the pulse sequence must be robust to main field and RF inhomogeneities. To achieve this, the double inversion‐recovery (DIR) preparation was adapted to use adiabatic pulses, with a slab‐selective reinversion replacing the previously used 2D pencil‐beam. The slab was oriented obliquely, in order to avoid upstream blood (e.g., left ventricle) or the navigator beam. Phantom experiments suggest that at 3 T, this approach improves both the net profile of the DIR pulse pair and the restoration of magnetization in the navigator region. Using this method, the feasibility of 3D coronary vessel wall imaging was demonstrated at 3 T. Fourteen healthy subjects were scanned using a segmented gradient‐echo sequence with prospective navigator gating. Good‐quality images of left and right coronary arteries were obtained, with SNR values of 29.7 ± 7.5 (vessel wall); 10.5 ± 4.4 (blood); 14.3 ± 5.2 (fat); and 45.6 ± 18.0 (myocardium). No problems occurred with ECG‐gating or power deposition (SAR) limits. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
A novel intensive induction therapy for high‐risk neuroblastoma utilizing sequential peripheral blood stem cell collection and infusion as hematopoietic support
Authors: Pradhan Kamnesh R. , Johnson Cynthia S. , Vik Terry A. , Sender Leonard S. , Kreissman Susan G.
Published: October 2005

Objective

To determine the feasibility, toxicities, and the response rate (RR) of a dose intensive, submyeloablative, induction chemotherapy protocol termed EPiC (etoposide, carboplatin, and intensive cyclophosphamide) utilizing sequential peripheral blood stem cell (PBSC) collection and infusion as hematopoietic support in children with newly diagnosed Stage 4 neuroblastoma.

Patients and Methods

Twenty‐five children (age >1 year) with Stage 4 neuroblastoma were enrolled. First and third cycles consisted of cyclophosphamide (4 gm/m2) and carboplatin (400 mg/m2). Second and fourth cycles consisted of carboplatin (1 gm/m2), and etoposide (450 mg/m2). PBSC were collected following Cycles 1, 2, and 3 and reinfused in each subsequent cycle. Following EPiC and surgical resection of the primary tumor, patients proceeded to various consolidation therapies. RR was scored using the International Neuroblastoma Response Criteria.

Results

Using PBSC infusion following EPiC chemotherapy resulted in a dose intensity averaging 85% of intended dose intensity; and in early neutrophil but not platelet recovery. PBSC were adequately collected in all, but one patient. The protocol had minimal non‐hematological toxicities. There was one toxic death. The overall RR was 78%, which included PR (partial response) and VGPR (very good partial response). The 5‐year event‐free survival and overall survival were 44% and 54%, respectively at a median follow‐up of 58.6 months.

Conclusion

EPiC is a feasible, well‐tolerated, sub‐myeloablative, induction chemotherapy protocol for children with high‐risk neuroblastoma. RR is equivalent to prior published studies, however, with minimal toxicities. Sequential PBSC collection and infusion is feasible even in very young children. Pediatr Blood Cancer © 2005 Wiley‐Liss, Inc.
Dose intensity of chemotherapy for osteosarcoma and outcome in the Cooperative Osteosarcoma Study Group (COSS) trials
Authors: Eselgrim Merle , Grunert Henrike , Kühne Thomas , Zoubek Andreas , Kevric Matthias , Bürger Horst , Jürgens Herbert , Mayer‐Steinacker Regine , Gosheger Georg , Bielack Stefan S.
Published: October 2005

Background

The prognostic relevance of dose intensity in the treatment of osteosarcoma is still under discussion. The aim of this study was to investigate whether higher dose intensities of chemotherapy correlated with better outcomes.

Procedure

This study contains 917 consecutive Cooperative Osteosarcoma Study Group (COSS) patients <40 years with primary, high‐grade central, nonmetastatic osteosarcoma of the extremities, who were in complete remission at least until day 200 after the start of chemotherapy. All COSS‐protocols were based on a uniform treatment concept of aggressive polychemotherapy and definitive surgery. Chemotherapy dose intensity in the first 200 days of treatment (DI200) and possible correlations to overall and event‐free survival were investigated. The study focused on methotrexate, doxorubicin, cisplatin, and ifosfamide, which are considered to be the most active drugs against osteosarcoma. Multivariate analyses including well‐known prognostic factors were added to complete this investigation.

Results

Until day 200, patients received 80.7 ± 26.1 g/m2methotrexate (MTX); 242 ± 69 mg/m2doxorubicin (DOX); 324 ± 133 mg/m2cisplatin (DDP); and 13.9 ± 9.8 g/m2ifosfamide (IFO) (mean ± SD). Median follow‐up from day 200 was 6.6 (0.02–22.1) years. There was no correlation between a higher DI200of any one drug and better outcomes in uni‐ or multi‐variate analyses. Total treatment intensity did not show such correlations either.

Conclusions

In an overall setting of intensive multidrug treatment of osteosarcoma, we could not prove that higher dose intensities correlate with better outcomes. Pediatr Blood Cancer © 2005 Wiley‐Liss, Inc.
Acute graft‐versus‐host disease of the heart
Authors: Roberts Stephen S. , Leeborg Nicky , Loriaux Marc , Johnson F. Leonard , Huang Meei‐Li , Stenzel Peter , Thiede Christian , Godder Kamar T.
Published: October 2005

Graft‐versus‐host disease (GVHD) is a frequent cause of morbidity and mortality after bone marrow transplantation. Acute GVHD most commonly involves the skin, gastrointestinal tract, and liver. Involvement of other organ systems is rare and remains controversial. We report a patient with GVHD who suffered a fatal ventricular arrhythmia shortly after bone marrow transplantation. Autopsy of the heart showed lymphocyte infiltration. Investigations for cardiotrophic viruses were negative, and chimerism analysis of the heart showed both donor and recipient DNA. We conclude that the cause of death was possibly graft‐versus‐host disease of the heart. A review of the literature revealed a total of 14 cases of possible cardiac GVHD. All but one of the reported cases have occurred in pediatric patients and six of those patients died, suggesting that this may be a rare but frequently fatal complication of pediatric allogeneic stem cell transplant. Pediatr Blood Cancer 2006; 47:624–628. © 2005 Wiley‐Liss, Inc.
ABCB1 over‐expression and drug‐efflux in acute lymphoblastic leukemia cell lines with t(17;19) and E2A‐HLF expression
Authors: Baudis Michael , Prima Victor , Tung Yoon Han , Hunger Stephen P.
Published: October 2005

Background

The t(17;19)(q21;p13), which occurs in a small subset of acute lymphoblastic leukemias (ALLs) and is associated with a dismal prognosis, creates a chimeric E2A‐HLF transcription factor with transforming properties.

Procedure

We used representational difference analysis to identify candidate E2A‐HLF target genes. Transient transfection assays and an inducible expression model system were then used to evaluate the ability of E2A‐HLF to modulate target gene expression.

Results

We identified ABCB1 (MDR1, P‐glycoprotein) as a gene differentially expressed in ALL cell lines with and without E2A‐HLF expression and demonstrated that t(17;19)+ ALL cell lines expressed high levels of ABCB1 protein and had a drug efflux‐positive phenotype. Although ABCB1 transcription is regulated by C/EBPβ via interaction with a DNA response element that shares significant homology with the optimal E2A‐HLF binding site, E2A‐HLF did not directly activate transcription of reporter genes under control of ABCB1 promoter elements in transient transfection assays. However, ABCB1 expression was induced in a DNA‐binding independent manner by E2A‐HLF, E2A‐PBX1, and truncated E2A polypeptides consisting of those portions of E2A present in leukemic fusion proteins.

Conclusions

E2A‐HLF‐mediated over‐expression of ABCB1 may play a critical role in defining the clinical phenotype of ALLs with a t(17;19), suggesting pharmacologic modulation of ABCB1 activity as a rational therapeutic strategy for this chemotherapy resistant subtype of ALL. Pediatric Blood Cancer 2006;47:757–764. © 2005 Wiley‐Liss, Inc.
Vincristine sulfate as a possible cause of optic neuropathy
Authors: Weisfeld‐Adams James D. , Dutton Gordon N. , Murphy Dermot M.
Published: October 2005

A 6‐year‐old boy with skin lesions suggestive of neurofibromatosis developed a frontotemporal primitive neuroectodermal tumor and was subsequently treated with surgery, craniospinal irradiation, and chemotherapy. After the sixth cycle of treatment with vincristine sulfate, 9 months after diagnosis, the child developed a rapidly progressive bilateral deterioration in visual acuity. Retinal appearances were consistent with optic neuropathy. Gene studies for neurocutaneous syndromes were negative. Brain imaging at this time showed no tumor progression, and in the absence of other etiologies, we implicate vincristine as a probable cause. Discontinuation of this particular agent has allowed bilateral improvement in visual acuity. Pediatr Blood Cancer 2007;48:238–240. © 2006 Wiley‐Liss, Inc.
Acid‐suppressing drugs and gastroesophageal reflux disease as risk factors for acute pancreatitis—results from a Swedish Case‐Control Study
Authors: Sundström Anders , Blomgren Kerstin , Alfredsson Lars , Wiholm Bengt‐Erik
Published: October 2005

Purpose

To study risk factors for acute pancreatitis, here with emphasis on gastro‐intestinal diseases and their treatments.

Methods

Population based case‐control study covering four areas in Sweden encompassing 2.2 million inhabitants. Included were 462 incident cases of acute pancreatitis aged 20–85 years, hospitalized from 1 January 1995–31 May 1998, and 1781 unmatched controls randomly selected from the study base using a population register. Information was captured from medical records and structured telephone interviews.

Results

Current use of H2 antagonists starting within 6 months of index‐date was associated with acute pancreatitis with an adjusted OR of 4.9 (95% confidence interval (CI) 1.6–15), and current use of proton pump inhibitors (PPIs) with an adjusted OR of 3.2 (95%CI 1.4–7.4). For both drug classes, the ORs tended to be higher at higher doses. Gastritis/gastro‐esophageal reflux disease (GERD) within the last 12 months not treated with PPIs or H2‐antagonists and inflammatory bowel disease (IBD) not treated with anti‐inflammatory or immunosuppressive drugs were associated with development of acute pancreatitis with adjusted odds ratios (OR) of 1.9 (95%CI 1.2–3.0) and 5.1 (95%CI 2.0–13) respectively.

Conclusions

Current IBD without treatment and gastritis/GERD without treatment were found to be associated with increased risks to develop acute pancreatitis but the nature of the latter association needs to be further evaluated. On balance, we judge that the observed associations between current use of H2‐antagonists and PPIs and increased risk of acute pancreatitis are unlikely to be explained by bias. Copyright © 2005 John Wiley & Sons, Ltd.
Epidemiological assessment of levodopa use in Cuba: 1993–1998
Authors: Lara G. , Cuadrado‐Gamarra J. I. , de Pedro‐Cuesta J. , Esteban E. M. , Giménez‐Roldán S. , Luis‐González S.
Published: October 2005

Purpose

The purpose of this study is to describe and evaluate the use of levodopa in Cuba in order to provide a basis for intervention aimed at improving pharmacological treatment of individuals presenting with Parkinson's disease (PD).

Methods

We studied the amount of levodopa, both plain and combined, distributed by the central laboratory to hospital and community pharmacies in Cuba in the period 1993–1998. An internationally established drug‐classification system and a reported method for epidemiological assessment of levodopa sales were applied. Sweden in 1994 served as the reference population.

Results

National crude rates of levodopa use basically remained stable since 1994, and in 1998 stood at 0.11 defined daily dose (DDD) per 1000 inhabitants/day, approximately 15 times lower than the corresponding figure for the reference population. Annual provincial use of levodopa showed considerable geographical variation, with the lowest rates in the eastern provinces and the highest rates in Havana City (Ciudad de La Habana). Adjustment for age reduced such differences by approximately 50%.

Conclusions

Levodopa use in Cuba is low and consistent with the reported low prevalence of the diagnosis of PD. Results suggest that the diagnosis and treatment of PD can be improved, with emphasis on better detection of PD. Copyright © 2005 John Wiley & Sons, Ltd.
Crystallization kinetics and morphology of poly(butylene succinate‐co‐adipate)
Authors: Ren Minqiao , Song Jianbin , Song Chunlei , Zhang Huiliang , Sun Xiaohong , Chen Qingyong , Zhang Hongfang , Mo Zhishen
Published: October 2005

The crystallization kinetics of biodegradable poly(butylene succinate‐co‐adipate) (PBS/A) copolyester was investigated by using differential scanning calorimetry (DSC) and polarized optical microscopy (POM), respectively. The Avrami and Ozawa equations were used to analyze the isothermal and nonisothermal crystallization kinetics, respectively. By using wide‐angle X‐ray diffraction (WAXD), PBS/A was identified to have the same crystal structure with that of PBS. The spherulitic growth rates of PBS/A measured in isothermal conditions are very well comparable with those measured by nonisothermal procedures (cooling rates ranged from 0.5 to 15 °C/min). The kinetic data were examined with the Hoffman–Lauritzen nucleation theory. The observed spherulites of PBS/A with different shapes and textures strongly depend on the crystallization temperatures. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3231–3241, 2005
AC and DC percolative conductivity of single wall carbon nanotube polymer composites
Authors: McLachlan David S. , Chiteme Cosmas , Park Cheol , Wise Kristopher E. , Lowther Sharon E. , Lillehei Peter T. , Siochi Emilie J. , Harrison Joycelyn S.
Published: October 2005

The equations needed to correctly interpret both AC and DC conductivity results of single wall carbon nanotube (SWNT) polymer composites and the scaling of these results onto a single master curve are presented. Brief discussions on the factors that determine the critical volume fraction (ϕc) and the percolation exponent (t) are also given. The results for a series of SWNT–polyimide composites are presented and the parameters obtained from fitting these results are discussed. The critical volume fraction for electrical percolation of the present composite was about 0.0005. Results obtained from previous work on SWNT (MWNT)–polymer composites and other percolation systems and the modeling (interpretation) of these results are also discussed and compared. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3273–3287, 2005
Preparation and characterization of PP/clay nanocomposites based on modified polypropylene and clay
Authors: Wu Jeng‐Yue , Wu Tzong‐Ming , Chen Wei‐Yan , Tsai Shih‐Jung , Kuo Wen‐Faa , Chang Gwo‐Yang
Published: October 2005

X‐ray diffraction and differential scanning calorimeter (DSC) methods have been used to investigate the crystallization behavior and crystalline structure of hexamethylenediamine (HMDA)‐modified maleic‐anhydride‐grafted polypropylene/clay (PP‐g‐MA/clay) nanocomposites. These nanocomposites have been prepared by using HMDA to graft the PP‐g‐MA (designated as PP‐g‐HMA) and then mixing the PP‐g‐HMA polymer in hot xylene solution, with the organically modified montmorillonite. Both X‐ray diffraction data and transmission electron microscopy images of PP‐g‐HMA/clay nanocomposites indicate that most of the swellable silicate layers are exfoliated and randomly dispersed into PP‐g‐HMA matrix. DSC isothermal results revealed that introducing 5 wt % of clay into the PP‐g‐HMA structure causes strongly heterogeneous nucleation, which induced a change of the crystal growth process from a three‐dimensional crystal growth to a two‐dimensional spherulitic growth. Mechanical properties of PP‐g‐HMA/clay nanocomposites performed by dynamic mechanical analysis show significant improvements in the storage modulus when compared to neat PP‐g‐HMA. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3242–3254, 2005
Deformation and fracture behavior of poly(vinylidene fluoride‐trifluorethylene) ferroelectric copolymer films under uniaxial tension
Authors: Fang F. , Zhang M. Z. , Huang J. F.
Published: October 2005

The deformation and fracture behavior under uniaxial tension was characterized for P(VDF‐TrFE) 68/32 mol % copolymer films prepared under two different processing conditions. It was found that the copolymer films prepared by solution casting and then annealing show a typical polymeric brittle fracture feature. For the copolymer films prepared by stretching the solution‐cast films and then annealing process, a typical linearly strengthening stage occurs in the stress–strain curve after yielding, and the polymer film samples fracture at a much larger maximum strain and a higher tensile strength than those prepared by the former process. SEM observation and XRD analysis were carried out to examine the morphology and microstructure change during uniaxial tension. The results show that for the stretched film samples, the polymer chains undergo slipping or further reorientation during uniaxial tension, causing the increase of the peak intensity in the X‐ray diffraction pattern. For the directly annealed ones, no yielding phenomenon is observed and there is no apparent X‐ray diffraction intensity change. It was suggested that the highly‐oriented fibril structure of the stretched film samples contributes to the linearly strengthening stage after yielding in the stress–strain curve. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3255–3260, 2005
DFT computational studies on rotation barriers, tautomerism, intramolecular hydrogen bond, and solvent effects in 8‐hydroxyquinoline
Authors: Shchavlev Andrew E. , Pankratov Alexei N. , Shalabay Alexei V.
Published: October 2005

Intramolecular hydrogen binding interactions in 8‐hydroxyquinoline, both in its zwitterionic tautomer and in the rotamer without the intramolecular hydrogen bond (IHB), have been computed using the B3LYP and MPW1K density functionals. The rotation of the OH bond and intramolecular proton transfer reactions were studied theoretically. The following theory levels have been applied: B3LYP/6‐31G(d,p), B3LYP/6‐311++G(d,p), MPW1K/6‐311++G(d,p), and MPW1K/6‐311++G(2d,3p)//MPW1K/6‐311++G(d,p). Natural bond orbital (NBO) analysis has also been carried out. The effect of medium (benzene, chloroform, tetrahydrofuran, 1,2‐dichloroethane, acetone, water) was simulated using the self‐consistent reaction field (SCRF) method within the framework of the polarizable continuum model (PCM), at the MPW1K/6‐311++G(d,p) level. The evolution of geometry, relative energies, heights of rotation (around the OH bond) and tautomerization barriers, IHB energies, and ΔG(solv) have been systematically investigated. The results obtained have shown the failure to neglect some changes of the above characteristics in polar media with respect to the gaseous phase. The series of stability of the forms under study in the gaseous phase remains the same in solution. Thus, in spite of the important role of the solvent electrostatic effects, the intrinsic stability of those species overcomes the solvent effects. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Gallium phosphides GAmPn(m+n= 2–5) and their anions: Structures, electron affinities, and vibrational frequencies
Authors: Guo Ling , Wu Haishun
Published: October 2005

Geometries, electronic states, and electron affinities of GamPnand GamP(m + n= 2–5) clusters have been examined using four hybrid and pure density functional theory (DFT) methods. Structural optimization and frequency analyses are performed with the basis of a 6‐311+G(2df)one‐particle basis set. The geometries are fully optimized with each DFT method independently. Three types of energy separations reported in this work are the adiabatic electron affinity (EAad), the vertical electron affinity (EAvert), and the vertical detachment energy (VDE). The calculation results show that the singlet structures have higher symmetry than that of doublet structures. The best method for predicting molecular structures was found to be BLYP, while other methods generally underestimated bond lengths. The most reliable adiabatic electron affinities and vertical detachment energy, obtained at the BP86 and B3LYP level of theory, are predicted to be 2.22 and 2.10 eV (GaP), 2.51 and 2.46 eV (Ga2P), 1.86 and 1.94 eV (GaP2), 1.96 and 2.27 eV (GaP3), 1.76 and 1.99 eV (Ga3P), 1.79 and 2.14 eV (Ga2P2), 2.85 and 3.67 eV (GaP4), 2.08 and 2.10 eV (Ga4P), 2.90 and 3.17 eV (Ga2P3), and 2.70 and 3.37 eV (Ga3P2), respectively. Those for Ga2P, Ga3P, Ga2P2, Ga4P, GaP4, Ga2P3, and Ga3P2are in good agreement with experiment, but the predicted EAadvalues for GaP, Ga2P, GaP2, and GaP3are larger than the available experimental values. For the vibrational frequencies of the GamPnseries, the B3LYP method produces good predictions with the average error only ∼10 cm−1from available experimental and theoretical values. The other three methods overestimate or underestimate the vibrational frequencies, with the worst predictions given by the BLYP method. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Theoretical study of the mechanism of CH2CO + CN reaction
Authors: Sun Hao , He Hong‐Qing , Hong Bo , Chang Ying‐Fei , An Zhe , Wang Rong‐Shun
Published: October 2005

The potential energy surface information of the CH2CO + CN reaction is obtained at the B3LYP/6‐311+G(d,p) level. To gain further mechanistic knowledge, higher‐level single‐point calculations for the stationary points are performed at the QCISD(T)/6‐311++G(d,p) level. The CH2CO + CN reaction proceeds through four possible mechanisms: direct hydrogen abstraction, olefinic carbon addition–elimination, carbonyl carbon addition–elimination, and side oxygen addition–elimination. Our calculations demonstrate that R→IM1→TS3→P3: CH2CN + CO is the energetically favorable channel; however, channel R→IM2→TS4→P4: CH2NC + CO is considerably competitive, especially as the temperature increases (R, IM, TS, and P represent reactant, intermediate, transition state, and product, respectively). The present study may be helpful in probing the mechanism of the CH2CO + CN reaction. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Quasi‐classical fluctuation–dissipation description of dielectric loss in oxides with implications for quantum information processing
Authors: Dunne Lawrence J. , Axelsson Anna‐Karin , Alford Neil McN. , Breeze Jonathan , Aupi Xavi , Brändas Erkki J.
Published: October 2005

One of the most important problems in developing devices for quantum computation is the coupling and dissipation of states by thermal noise. We present a study of a two‐state electric dipole in a crystal coupling to noise from a reservoir. As a realization of such an energy‐dissipating dipole, we report and analyze dielectric loss measurements in single crystal and polycrystalline Al2O3 over the temperature range 70–300 K. We are able to model the dielectric loss in terms of a quasi‐classical model that uses the fluctuation–dissipation theorem. Two key parameters in this model are the crystal oscillator energy and reservoir–lattice coupling constant. In polycrystalline samples, it is assumed that the main effect of structural disorder is a modification of the spectrum of the thermal phonons, so that acoustical vibrations acquire some optical mode character. The temperature dependence of the linewidth of the high dielectric strength infrared (IR) mode at 438 cm−1 and the quasi‐degenerate Raman mode of the k = 0 (418 cm−1) transition are also investigated and are shown to be related simply to the dielectric loss. The model reproduces the unusual temperature dependence of the dielectric loss observed experimentally. The implications for the coupling of quantum mechanical objects to noise and quantum information processing are discussed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Chiral discrimination in hydrogen‐bonded complexes of hydrogen peroxide with methyl hydroperoxide: Theoretical study
Authors: Du Dongmei , Zhou Zhengyu
Published: October 2005

For the first time, the discrimination of different chiral forms of 1:1 complexes with hydrogen peroxide and methyl hydroperoxide have been investigated using density functional theory (DFT) and Møller–Plesset type 2 (MP2) methods at varied basis set levels from 6‐31+G(d,p) to 6‐31++G(2d,2p). Three pairs of chiral enantiomers were considered. The optimized geometric parameters, interaction energies, and chirodiastatic energies for various isomers at different levels are estimated. To take into account the water solvation effect, the polarized continuum model (PCM) method has been used to evaluate the ΔGsolv. The gas phase results show that the heterochiral six‐membered ring complex (structure I) and homochiral five‐membered ring complexes (structures IV and V) are preferred configurations for the three pairs of chiral enantiomers. The solvation effect on six‐membered ring complexes (structures I and II) shows nonsignificant changes in the configurations preferred, but on five‐membered ring complexes, the homo‐/heterochiral preference is found to be inverse in the polar solvent. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Theoretical study of CH…O hydrogen bond in proton transfer reaction of glycine
Authors: Selvarengan P. , Kolandaivel P.
Published: October 2005

Density functional theory (DFT) calculations are used to study the strength of the CH…O H‐bond in the proton transfer reaction of glycine. Comparison has been made between four proton transfer reactions (ZW1, ZW2, ZW3, SCRFZW) in glycine. The structural parameters of the zwitterionic, transition, and neutral states of glycine are strongly perturbed when the proton transfer takes place. It has been found that the interaction of water molecule at the side chain of glycine is high in the transition state, whereas it is low in the zwitterionic and neutral states. This strongest multiple hydrogen bond interaction in the transition state reduces the barrier for the proton transfer reaction. The natural bond orbital analysis have also been carried out for the ZW2 reaction path, it has been concluded that the amount of charge transfer between the neighboring atoms will decide the strength of H‐bond. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Study of the mass spectrometric fragmentation of pseudouridine: comparison of fragmentation data obtained by matrix‐assisted laser desorption/ionisation post‐source decay, electrospray ion trap multistage mass spectrometry, and by a method utilising electrospray quadrupole time‐of‐flight tandem mass spectrometry and in‐source fragmentation
Authors: Dudley Edward , Tuytten Robin , Bond Alison , Lemière Filip , Brenton A. Gareth , Esmans Eddy L. , Newton Russell P.
Published: October 2005

Many nucleosides and their modified forms have been studied by mass spectrometry elaborating the detailed fragmentation pathways under MS2 and MSn conditions. Although the C‐nucleoside pseudouridine has been fragmented and studied briefly, usually amongst many other nucleosides, it has not been investigated to the same extent as other nucleosides. In this report a number of different mass spectrometric techniques are applied to obtain a fuller picture of pseudouridine fragmentation. At the same time this study is used to compare different tandem mass spectrometric techniques, including a novel methodology utilising a quadrupole time‐of‐flight (Q‐ToF) instrument for MSn analysis comparable with that available with an ion trap mass spectrometer. Copyright © 2005 John Wiley & Sons, Ltd.
Noncovalent complex formation of tetratosylated resorcarene with aromatic, aliphatic, and cyclic alkyl ammonium ions: a mass spectrometric study of complex properties
Authors: Ventola Elina , Pirskanen Atte , Vainiotalo Pirjo
Published: October 2005

The ability of tetratosylated resorcarene to form complexes with aromatic ammonium ions was investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The formation of noncovalent complexes, [1+guest]+ and [1 · 1+guest]+, as observed with singly charged aromatic anilinium and phenylene aminoammonium guests. Comparison of the complexation efficiencies of the aromatic and aliphatic ammonium ions showed the importance of proton affinity of conjugate amines in complex formation. In collision‐induced dissociation experiments, gas‐phase stability was found to be lower for complexes formed with aromatic ions and this behavior was not found to depend on the proton affinity of conjugate amines. Fast oxidation of the para and ortho aminoammonium ions and complexation of these ions with tetratosylated resorcarene was observed. Copyright © 2005 John Wiley & Sons, Ltd.
Dansylation of tryptic peptides for increased sequence coverage in protein identification by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric peptide mass fingerprinting
Authors: Park Soo‐Jin , Song Jin‐Su , Kim Hie‐Joon
Published: October 2005

A database search using peptide mass fingerprints obtained by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry leads to protein identification with incomplete sequence coverage, because certain peptides are preferentially desorbed/ionized and some are not detected at all. We show that certain tryptic peptides mainly with C‐terminal arginine not detected before derivatization become detectable upon dansylation. Others, mainly with C‐terminal lysine, are suppressed. An increase in protein sequence coverage and protein identification score by combined data from underivatized and dansylated peptides in database search is demonstrated using human amnion proteins (human serum albumin precursor, calmodulin, collagen alpha 2(VI) chain precursor, galectin‐3) separated by two‐dimensional gel electrophoresis as well as femtomole amounts of BSA in solution. Copyright © 2005 John Wiley & Sons, Ltd.
Characterization of a new methylated β‐cyclodextrin with a low degree of substitution by electrospray ionization mass spectrometry and liquid chromatography/mass spectrometry
Authors: Jacquet Romain , Elfakir Claire , Lafosse Michel
Published: October 2005

A new methylated β‐cyclodextrin (Me‐β‐CD) with a low degree of substitution (DS) was characterized by electrospray ionization mass spectrometry (ESI‐MS) and liquid chromatography coupled with ESI‐MS (LC/ESI‐MS). For ESI‐MS analyses, the composition of the infused sample solution was optimized in order to obtain only singly charged ammoniated CDs without fragmentation. The DS value (i.e. the number of methyl groups per glucopyranose unit) was found to be 0.7, which was in accordance with the values previously obtained by other methods. The LC/ESI‐MS analysis, derived from a method using evaporative light scattering detection, allowed the study of the substitution isomers of each derivative and appears to be an easy and rapid tool for the accurate characterization of Me‐β‐CD mixtures. Copyright © 2005 John Wiley & Sons, Ltd.
Structural determination of the novel fragmentation routes of morphine opiate receptor antagonists using electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry
Authors: Joly Nicolas , Aneed Anas El , Martin Patrick , Cecchelli Roméo , Banoub Joseph
Published: October 2005

Electrospray ionization quadrupole time‐of‐flight (ESI‐QqToF) mass spectra of naltrindole hydrochloride 1, naltriben mesylate 2, and naltrexone hydrochloride 3, a common series of morphine opiate receptor antagonists, were recorded using different declustering potentials. Low‐energy collision‐induced dissociation (CID) MS/MS experiments established the fragmentation routes of these compounds. In addition, re‐confirmation of the various established fragmentation routes was effected by conducting a series of ESI‐CID‐QqTof‐MS/MS experiments using non‐conventional quasi MSn (up to MS8) product ion scans, which were initiated by CID in the atmospheric pressure/vacuum interface using a higher declustering potential. Precursor ion scan analyses were also performed with a conventional quadrupole‐hexapole‐quadrupole tandem mass spectrometer and allowed the confirmation of the genesis of some diagnostic ions. Copyright © 2005 John Wiley & Sons, Ltd.
Uniformity of ionization response of structurally diverse analytes using a chip‐based nanoelectrospray ionization source
Authors: Hop Cornelis E. C. A. , Chen Yue , Yu Li J.
Published: October 2005

The major drawback of liquid chromatography/mass spectrometry (LC/MS) for the analysis of mixtures is the non‐quantitative nature of these studies. The ionization efficiency of the various components in the mixture (e.g., a compound and its metabolites) can vary greatly and, therefore, relative intensities of signals cannot be related to relative abundance. A chip‐based nanoelectrospray ionization source was used to compare the ionization efficiencies of compounds with different physical‐chemical characteristics. The data indicate that the ionization efficiencies vary much less with the chip‐based device than by LC/MS. This was ascribed to the generation of a much higher electric field around the nozzles, which supplies a large excess of protons to the small droplets and reduces/eliminates the differences in the ionization efficiency for the analytes. Copyright © 2005 John Wiley & Sons, Ltd.
Identification and mass spectrometric characterization of glycosylated flavonoids in Triticum durum plants by high‐performance liquid chromatography with tandem mass spectrometry
Authors: Cavaliere Chiara , Foglia Patrizia , Pastorini Elisabetta , Samperi Roberto , Laganà Aldo
Published: October 2005

A mass spectrometric method for extensive detection and semi‐quantitative determination of flavonoid glycosides in stem and leaves of young Triticum durum plants is presented. About 100 g of sample were lyophilized and ground, and the compounds of interest were then extracted, cleaned‐up, and fractionated using high‐performance liquid chromatography (HPLC). Tandem mass spectrometry analyses were performed using a quadrupole‐linear ion trap instrument with an information‐dependent data acquisition (IDA) protocol that looped two experiments, enhanced MS scan and enhanced product ion scan. Various glycoconjugates, which are all derivatives of only four flavones, apigenin, luteolin, chrysoeriol and tricin, were identified and belong to the following categories: 7 monoglycosides, 31 diglycosides, 15 triglycosides and 1 tetraglycoside. Among these some acylated glycosides were found. Tricin derivatives are present exclusively as O‐glycosides, while apigenin and luteolin are present always as C‐glycosides. Semi‐quantitative estimation was performed by using the monoglycoside and diglycoside of quercetin as internal standards. Copyright © 2005 John Wiley & Sons, Ltd.
PET imaging of striatal dopamine D2 receptors in nonhuman primates: Increases in availability produced by chronic raclopride treatment
Authors: Czoty Paul W. , Gage H. Donald , Nader Michael A.
Published: October 2005

Previous research using positron emission tomography (PET) in monkeys has shown that attaining social dominance can result in increased DA D2 receptor availability and attenuated sensitivity to the reinforcing effects of cocaine. The present study utilized a within‐subjects design to determine whether chronic treatment with the D2 receptor antagonist raclopride could similarly increase D2 receptor availability. Using the D2‐selective radioligand [18F]fluoroclebopride (FCP), three adult male cynomolgus monkeys were scanned before and after chronic treatment with raclopride (0.01 mg/kg per h for 30 ± 1 day) administered by a subcutaneous osmotic pump. Food‐reinforced operant behavior was assessed during treatment. A transitory decrease in responding was observed during the initial eight days of raclopride treatment. Tolerance developed by the tenth session, and responding remained at baseline levels for the duration of treatment and after treatment was discontinued. Averaged across monkeys, chronic raclopride administration increased FCP distribution volume ratios (DVRs) between 12 and 20% in the caudate nucleus, putamen, and anterior cingulate cortex. When monkeys were re‐scanned 9–12 months after termination of raclopride treatment, FCP DVRs remained elevated in two subjects, and decreased below baseline levels in the third monkey. Considering the reported 2% test/retest variability for FCP, these findings indicate that chronic treatment with a D2 receptor antagonist can produce large increases in D2 receptor availability as measured with PET. Individual differences in rates of recovery were observed, such that the increases in DVR persisted in two of three subjects. Synapse 58:215–219, 2005. © 2005 Wiley‐Liss, Inc.
Dopamine agonist action of phencyclidine
Authors: Seeman Philip , Lasaga Mercedes
Published: October 2005

Although the psychotomimetic action of phencyclidine is often used to model a hypoglutamate theory of psychosis or schizophrenia, work also exists showing that phencyclidine has a significant affinity for the dopamine D2 receptor. The present study was done to determine whether phencyclidine has a direct functional dopamine‐like action on cells. The effect of phencyclidine was tested on the release of prolactin from rat cultured anterior pituitary cells. It was found that the release of prolactin was 50% inhibited by 4 nM phencyclidine. This strong dopamine‐like agonist action at the functional high‐affinity state of the dopamine D2 receptor by the phencyclidine psychotomimetic is consistent with the dopamine hypothesis of psychosis. Synapse 58:275–277, 2005. © 2005 Wiley‐Liss, Inc.
Pain and pain‐related fear are associated with functional and social disability in an occupational setting: Evidence of mediation by pain‐related fear
Authors: Gheldof Els L.M. , Vinck Jan , Van den Bussche Eva , Vlaeyen Johan W.S. , Hidding Alita , Crombez Geert
Published: October 2005

This study examined the role of work‐related, psychosocial and psychological factors in predicting functional and social disability in working employees. In a cross‐sectional design, 890 working employees (reporting at least 1 day of back pain during the past year) completed self‐report measures of back pain, disability, pain‐related fear, negative and positive affectivity, job satisfaction, job stress and physical work load. Regression analyses revealed that pain intensity was a strong predictor of functional (β = .69, p < .001) and social disability (β = .67, p < .001). Fear of (re)injury due to movement (β = .25, p < .001; β = .28, p < .001) had additional predictive value in both models. Further, (singular) mediation tests indicated that fear for (re)injury partially mediated the relation between pain intensity and disability, and between negative affectivity and disability. Finally, path analyses revealed both fear and pain intensity as mediators between negative affectivity and disability. Overall, our findings point at the relevance of the cognitive‐behavioral model of avoidance in occupational settings.
The NK1‐receptor antagonist TKA731 in painful diabetic neuropathy: A randomised, controlled trial
Authors: Sindrup Søren H. , Graf Ana , Sfikas Nikolaos
Published: October 2005

Substance P is one of the neurotransmitters released by primary nociceptive neurons in the dorsal horn of the spinal cord and it binds postsynaptically to NK1‐receptors. This receptor is therefore an obvious target for analgesic drugs. The aim of this multicenter, randomised, double‐blind, placebo‐controlled and parallel‐group study was to test if the non‐peptide NK1‐receptor antagonist TKA731 would relieve painful diabetic polyneuropathy. Eighty‐seven patients completed a treatment period of 2 weeks' duration with TKA731 (150 mg daily) or placebo preceded by one week for baseline observations. There was no significant difference between TKA731 and placebo in change in pain rating from baseline to study end neither for rating of total pain (mean −13.4 mm vs. −11.6 mm, p = 0.664) nor for change in ratings of different pain symptoms (touch‐ or pressure‐evoked pain, pain paroxysms, steady burning or deep aching pain) (p = 0.169‐0.834).
Expectancy, fear and pain in the prediction of chronic pain and disability: A prospective analysis
Authors: Boersma Katja , Linton Steven J.
Published: October 2005

Studies with (sub) acute back pain patients show that negative expectancies predict pain and disability at a one‐year follow up. Yet, it is not clear how expectations relate to other factors in the development of chronic disability such as pain and fear. This study investigates the relationship between expectations, pain‐related fear and pain and studies how these variables are related to the development of chronic pain and disability. Subjects (N = 141) with back and/or neck pain (duration <1 year) were recruited via primary care. They completed measures on pain, expectancy, pain‐related fear (pain‐related negative affect and fear avoidance beliefs) and function. A one‐year follow up was conducted with regard to pain and function. It was found that pain, expectancy, pain‐related fear and function were strongly interrelated. In the cross‐sectional analyses negative expectancies were best explained by frequent pain and a belief in an underlying and serious medical problem. Prospectively, negative expectancy, negative affect and a belief that activity may result in (re) injury or increased pain, explained unique variance in both pain and function at one‐year follow up. In conclusion, expectancy, negative affect and fear avoidance beliefs are interrelated constructs that have predictive value for future pain and disability. Clinically, it can be helpful to inquire about beliefs, expectancy and distress as an indication of risk as well as to guide intervention. However, the strong interrelations between the variables call for precaution in treating them as if they were separate entities existing in reality.
Voltage‐dependent synchronization of gating of syringomycin E ion channels
Authors: Ostroumova O.S. , Malev V.V. , Kaulin Yu.A. , Gurnev Ph.A. , Takemoto J.Y. , Schagina L.V.
Published: October 2005

Antifungal lipodepsipeptide syringomycin E (SRE) forms two major conductive states in lipid bilayers: “small” and “large”. Large SRE channels are cluster of several small ones, demonstrating synchronous opening and closure. To get insight into the mechanism of such synchronization we investigated how transmembrane potential, membrane surface charge, and ionic strength affect the number of small SRE channels synchronously functioning in the cluster. Here, we report that the large SRE channels can be presented as 3–8 simultaneously gating small channels. The increase in the absolute value of the transmembrane potential (from 50 to 200 mV) decreases the number of synchronously gated channels in the clusters. Voltage‐dependence of channel synchronization was influenced by the ionic strength of the bathing solution, but not by membrane surface charge. We propose a mechanism for the voltage‐dependent cluster behavior that involves a voltage‐induced reorientation of lipid dipoles associated with the channel pores.
The dimer interface of the SARS coronavirus nucleocapsid protein adapts a porcine respiratory and reproductive syndrome virus‐like structure
Authors: Chang Chung-ke , Sue Shih-Che , Yu Tsan-hung , Hsieh Chiu-Min , Tsai Cheng-Kun , Chiang Yen-Chieh , Lee Shin-jye , Hsiao Hsin-hao , Wu Wen-Jin , Chang Chi-Fon , Huang Tai-huang
Published: October 2005

We have employed NMR to investigate the structure of SARS coronavirus nucleocapsid protein dimer. We found that the secondary structure of the dimerization domain consists of five α helices and a β‐hairpin. The dimer interface consists of a continuous four‐stranded β‐sheet superposed by two long α helices, reminiscent of that found in the nucleocapsid protein of porcine respiratory and reproductive syndrome virus. Extensive hydrogen bond formation between the two hairpins and hydrophobic interactions between the β‐sheet and the α helices render the interface highly stable. Sequence alignment suggests that other coronavirus may share the same structural topology.
Non‐cell autonomous RNA silencing
Authors: Voinnet Olivier
Published: October 2005

In plants and in some animals, the effects of post‐transcriptional RNA silencing can extend beyond its sites of initiation, owing to the movement of signal molecules. Although the mechanisms and channels involved are different, plant and animal silencing signals must have RNA components that account for the nucleotide sequence‐specificity of their effects. Studies carried out in plants and Caenorhabditis elegans have revealed that non‐cell autonomous silencing is operated through specialized, remarkably sophisticated pathways and serves important biological functions, including antiviral immunity and, perhaps, developmental patterning. Recent intriguing observations suggest that systemic RNA silencing pathways may also exist in higher vertebrates.
Analysis and improvement of delivery operations at the San Francisco Public Library
Authors: Apte Uday M. , Mason Florence M.
Published: October 2005

Urban public library systems have always transported and delivered library materials within their branch systems. In recent years, however, the introduction of internet‐based, online library catalog systems has allowed users to search the library's catalog, select and reserve a book or a video and have it delivered to the branch of their choice. Consequently, the demand for delivery services is increasing at rapid rate in large urban public libraries systems.

Having experienced a similar growth in the demand for delivered items, the San Francisco Public Library (SFPL) commissioned a study to improve its delivery operations. Using operations management concepts, such as pre‐sorting of material to avoid double handling, cross docking to reduce cycle time of delivery, and workload balancing among delivery routes to effectively increase delivery capacity, the delivery operations were restructured. We developed optimization models for library delivery operations that specifically accounted for pre‐sorting, cross docking and route balancing. We also developed heuristics for solving these models and implemented them to redesign the delivery operations at SFPL.

The redesigned delivery operations will reduce the cycle time and the cost of delivery by almost half. Furthermore, through balanced utilization of existing truck capacities, the delivery operations will be able to handle significantly larger delivery volume and thereby accommodate future delivery service growth without additional investments. The operations management concepts and techniques illustrated in this paper through the example of SFPL should prove to be useful to other urban, multi‐branch library systems as they deal with their delivery challenges.