bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wnt/Frizzled signaling in Ewing sarcoma
Authors: Üren Aykut , Wolf Vladimir , Sun Yu‐Feng , Azari Amir , Rubin Jeffrey S. , Toretsky Jeffrey A. 
Published: June 2004

AbstractBackgroundThe Ewing sarcoma family of tumors (ESFT) is a set of neuroectodermal malignancies that typically presents in the second decade and has a poor prognosis due to metastatic disease. Wnt signaling has a critical role in the normal development of multiple neuroectodermal tissues and also contributes to the neoplastic properties of tumor cells of neuroectodermal origin.ProcedureWe surveyed the expression of Wnts and their receptors in nine ESFT cell lines by RT‐PCR analysis. We also tested biological response of ESFT cell lines to exogenous Wnts in β‐catenin stabilization, actin stress fiber formation, and chemotaxis assays.ResultsWe detected Wnt‐10b in all the lines, and most also expressed Wnt‐5a, Wnt‐11, and Wnt‐13. Several Frizzleds (Fz) and the Wnt co‐receptors, low density lipoprotein‐receptor‐like proteins 5 and 6 were also expressed. We observed a marked stimulation of the β‐catenin/canonical Wnt pathway in ESFT cells treated with Wnt‐3a. Wnt‐3a induced morphologic changes characterized by the formation of long cytoplasmic extensions in ESFT cells. We also observed chemotaxis of ESFT cells in response to Wnt‐3a.ConclusionsThese results provide evidence that components of Wnt/Fz pathway are expressed and an intact Wnt/Frizzled signaling pathway exists in ESFT cell lines. Activation of the Wnt pathway in ESFT suggests that Wnt modulates cell motility rather than cell proliferation. Hence, activation of this pathway may influence metastatic potential of ESFT. © 2004 Wiley‐Liss, Inc.
Is routine chest radiography necessary for the initial evaluation of fever in neutropenic children with cancer?
Authors: Renoult Edith , Buteau Chantal , Turgeon Nathalie , Moghrabi Albert , Duval Michel , Tapiero Bruce 
Published: June 2004

AbstractBackgroundThe yield of routine chest radiography (CXR) as part of the initial management of febrile neutropenic pediatric oncology patients is questionable.ProcedureWe retrospectively analyzed the clinical records of neutropenic (absolute neutrophil count ≤0.5 × 109/L) children with cancer, admitted with oral temperature ≥38°C to our institution, between January 2001 and October 2002. Following admission, patients received tobramycin plus (piperacillin or ticarcillin–clavulanic acid). Admission routine CXRs were reviewed. Clinical and radiological features were compared with the discharge diagnosis. Age, underlying disease, and the presence of pulmonary symptoms or signs were studied as possible predictors of CXR findings related to pneumonia.ResultsIn total, 88 patients experienced 170 episodes of fever. A routine admission CXR was obtained for 157 of the episodes. Radiologists found 20 (12.7%) abnormal CXR (6 with a segmental or lobar consolidation considered as a pneumonia). In addition, two patients with abnormal admission CXR developed lobar consolidation on a repeat film, later in their hospital course. There were no differences in age and type of underlying disease between children with or without pneumonia. Respiratory symptoms were initially present in 58 cases. Seven (12%) had pneumonia. Among the 99 asymptomatic cases only one (1%) patient had a pneumonia (P = 0.0041). This child had a positive blood culture for P. aeruginosa at the time of admission. None of the children had initial therapy modified on the basis of radiologic findings.ConclusionIn this study, pneumonia is an unusual cause of fever (5%), especially in the absence of respiratory signs or symptoms (1%). Admission CXR should be reserved for the neutropenic pediatric oncology patient presenting with fever and abnormal respiratory findings. © 2004 Wiley‐Liss, Inc.
The discovery of two kinds of ion pairs
Authors: Smid Johannes 
Published: June 2004

AbstractThe discovery and implications of the existence of two kinds of ion pairs in solutions of carbanion salts is described. Also discussed are the factors controlling tight–loose ion pair equilibrium: the nature of the carbanion and its counterion, temperature, pressure, solvent, and cation‐complexing additives. A few examples are presented of the effect of these ionic species on the mechanisms of anionic polymerization and proton transfer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3655–3667, 2004
PREDICT modeling and in‐silico screening for G‐protein coupled receptors
Authors: Shacham Sharon , Marantz Yael , Bar‐Haim Shay , Kalid Ori , Warshaviak Dora , Avisar Noa , Inbal Boaz , Heifetz Alexander , Fichman Merav , Topf Maya , Naor Zvi , Noiman Silvia , Becker Oren M. 
Published: June 2004

AbstractG‐protein coupled receptors (GPCRs) are a major group of drug targets for which only one x‐ray structure is known (the nondrugable rhodopsin), limiting the application of structure‐based drug discovery to GPCRs. In this paper we present the details of PREDICT, a new algorithmic approach for modeling the 3D structure of GPCRs without relying on homology to rhodopsin. PREDICT, which focuses on the transmembrane domain of GPCRs, starts from the primary sequence of the receptor, simultaneously optimizing multiple ‘decoy’ conformations of the protein in order to find its most stable structure, culminating in a virtual receptor‐ligand complex. In this paper we present a comprehensive analysis of three PREDICT models for the dopamine D2, neurokinin NK1, and neuropeptide Y Y1 receptors. A shorter discussion of the CCR3 receptor model is also included. All models were found to be in good agreement with a large body of experimental data. The quality of the PREDICT models, at least for drug discovery purposes, was evaluated by their successful utilization in in‐silico screening. Virtual screening using all three PREDICT models yielded enrichment factors 9‐fold to 44‐fold better than random screening. Namely, the PREDICT models can be used to identify active small‐molecule ligands embedded in large compound libraries with an efficiency comparable to that obtained using crystal structures for non‐GPCR targets. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Fault tree analysis for risk assessment in the Borexino experiment
Authors: Caputo Antonio C. , Palumbo Mario , Tartaglia Roberto 
Published: June 2004

AbstractThis paper outlines a methodological approach utilizing quantitative risk analyses and cost–benefits evaluation in order to select the most cost‐effective options for risk reduction in industrial plants including structural changes and preventive maintenance. The methodology is based on quantification of top events resorting to fault trees, a sensitivity analysis of the probability of occurrence of top events, and a comparison of corrective measures based on cost and effectiveness criteria. The method is applied to a case study represented by the pseudocumene purification plant of the Borexino experiment in order to show its capability. The experiment is located in the Gran Sasso National Laboratory operated by the Italian National Institute for Nuclear Physics. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 121–131, 2004
Estimation of risk indices of chemicals during transportation
Authors: Rao K. Rajeshwar , Rao S. Venkateswar , Chary V. 
Published: June 2004

AbstractThe National Fire Protection Association (NFPA) rankings for health, flammability, reactivity, and special hazards have been considered the basis for calculating the risk indices of materials in transportation as they have adopted the United Nations criteria for toxicity and corrosivity, which also addresses hazards in transportation to some extent. Using these NFPA rankings a method has been developed to calculate the risk indices of chemicals during transportation. Other factors such as quantity of material moving, distance between the point of release and population, rate of dispersion and probability of an accident were also considered in this paper for calculating the transportation risk index of a chemical. This index can be used as a guide for assessing the potential hazards of a chemical during its transportation. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 149–154, 2004
Emergency venting requirements for tempered systems considering partial vapor–liquid separation with disengagement parameters greater than unity: Part II: Application
Authors: D'Alessandro Robert 
Published: June 2004

AbstractPart 1 of this two‐paper series presented closed‐form analytical expressions for the two‐phase emergency relief requirements of top‐vented vertical cylindrical containers when the fluids involved exhibit partial disengagement. Both churn‐turbulent flow and bubbly flow fluid behaviors, with disengagement parameters greater than unity, were considered. Energy input from either runaway reactions or uncontrolled external heat was included. The methods are limited to systems that are tempered and do not contain noncondensable components. In Part 2, the models developed in Part 1 are applied to specific points along the venting transient, yielding expressions for the required flow rate under emergency conditions. Part 2 elaborates on the limitations of the models, illustrates the use of the models with numerical examples, and compares the results against previous work. The effect of disengagement parameters greater than unity is illustrated in terms of both the required relieving rate and the mass remaining inside the container when disengagement occurs. © 2004 American Institute of Chemical Engineers Process Sag Prog 23: 86–98, 2004
Process safety in the future—A view from the chemistry
Authors: Leggett David J. 
Published: June 2004

AbstractThis paper advances the thesis that a complete assessment of the chemical process safety must be founded on specific chemical hazards data. Usually, these data can only be obtained from appropriately designed experiments using the correct testing techniques. The basis of safety and the window of safe operations arise from the relevant process safety data.BakerRisk's experience with the chemical processing industry (CPI) has shown that the PSM elements Safety Information, Process Hazards Analysis, and Operating Procedures are often documented without adequate hazards test data for the covered process. The information is often qualitative; it may be taken from inappropriate laboratory data and may not address the specific process deviation or worst‐case situation(s). This lack of hazards test data represents an information void that tabletop or literature process hazard analyses alone cannot fill. Five observations and recommendations are offered:

Chemical process safety supported by hazards testing is the right thing to do, whether the process is covered or not and whether the process is at the manufacturing stage or not;
Hazards testing to identify and evaluate potential upset conditions should be an integral part of a company's process safety program. It is a major information source for process hazard analyses;
The information obtained is specific to the thermodynamics and kinetics of the process chemistry;
The information enables clear identification of operational, thermal, and reactivity hazards of processes involving highly hazardous chemicals;
The scope of the chemical hazards testing should be matched with the quantities of chemicals involved and the development stage of the product. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 163–169, 2004
A fast thermal activity interpreter for controlling chemical reaction hazards
Authors: Fauske Hans K. 
Published: June 2004

AbstractA quick and inexpensive method to facilitate product control in assuring safe chemicals management in transportation and storage is introduced. Product safety measures related to large quantities of reactive chemicals require frequent measurements of thermal activity (TA) at low temperature in order to control the potential for contamination, etc., that can accelerate the reaction rate.The fast thermal activity interpreter (FTAI) instrument is designed to monitor chemical systems undergoing gaseous decomposition reactions with the capability of interpreting TAs of the order of 1 μW/g or a self heat rate of the order of 10−5°C min−1. Recognizing the need for frequent sampling, the FTAI takes about 1 h to run an analysis.The FTAI concept provides an easy means for determining activation energies and rate laws of gaseous decomposition reactions at ambient temperature conditions and is also well suited to measure material oxidation or corrosion reaction rates involving oxygen consumption. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 108–113, 2004
Application of chain of events analysis to process safety management
Authors: Triplett Timothy L. , Zhou Yifeng , Mannan M. Sam 
Published: June 2004

AbstractProcess industries rely on process control and safety instrumented systems (SIS) to minimize the potential and consequence of hazardous incidents. As the computer‐based systems become more complex, there is the potential for inaccuracies and errors in program logic to introduce new causes of process deviations (abnormal situations) to the process plant. Finding these errors requires extensive review of the software utilizing traditional document tools. The novel chain‐of‐events analysis provides an effective aid in this process by extracting the linkage information from the system and creating an interaction table from which displays and reports may be generated to illustrate the influencing relationships among process control and SIS entities (points and their parameters). This method is also useful for routine maintenance and operation of a facility. It also provides assistance in analyzing alarms for abnormal situation management. © 2004 American Institute of Chemical Engineers Process Saf Prog 23: 132–135, 2004
Laser‐assisted conductance of molecular wires: Two‐photon contributions
Authors: Urdaneta I. , Keller A. , Atabek O. , Mujica V. 
Published: June 2004

AbstractWe extend to second order in the field intensity a previously obtained first‐order expression for the conductance of a tight‐binding molecular wire, bridging two electrodes, illuminated by a weak laser. The higher‐order term brings in corrections due to two‐photon processes that, for low intensities and strong molecule–electrode contacts, are several orders of magnitude smaller than the first‐order leading terms. For other ranges of parameters, the second‐order correction may be significant mostly due to processes involving the absorption or emission of two photons. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Alternative techniques in open‐shell SCF theory
Authors: Glushkov V. N. 
Published: June 2004

AbstractAn alternative to the Roothaan's open‐shell method that does not involve off‐diagonal Lagrangian multipliers has been proposed. The orthogonality of the closed‐ and open‐shell orbitals is discussed. Two possible schemes of designing the restricted open‐shell Hartree–Fock (HF) wave functions are discussed: In the first scheme the self‐consistent field (SCF) functions are linear combination of Slater determinants with coefficients fixed by symmetry whereas the second one uses the unrestricted HF formalism to build a single open‐shell Slater determinant from which a well‐defined open‐shell Møller–Plesset‐like perturbation theory can be performed. It has been shown that the Euler SCF equations based on the proposed technique lead to an optimum set of orbitals satisfying the correct variational conditions. A structure and correspondence of the proposed equations to those of the conventional approach are discussed. Practical calculations carried out at SCF and perturbation theory levels demonstrate some features of the proposed technique. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Macroconfigurations in molecular electronic structure theory
Authors: Khait Yuriy G. , Song Jie , Hoffmann Mark R. 
Published: June 2004

AbstractBased on the well‐known idea of dividing a molecular orbital set into groups, and imposing restrictions on allowed group occupancies, a more general formalism, which we refer to as the macroconfiguration approach, is developed. The approach is shown to be useful in four complementary contexts: First, as with previous uses of orbital groupings, physical considerations can actively be taken into account in constructing configuration spaces; second, the approach is demonstrated to enable the screening of a vast number of noninteracting electron configuration pairs in a computationally efficient manner; third, all advantages of the Table–configuration interaction (CI) technique can be used effectively for evaluating Hamiltonian matrix elements between interacting configurations; finally, the macroconfiguration technique provides an efficient way of regenerating excited configurations as needed in a calculation. These characteristics indicate that the suggested approach is promising for improving the computational efficiency of methods describing electron dynamic correlation and, in particular, for CI calculations involving highly (e.g., triply and quadruply) excited configurations and for methods of effective Hamiltonian theory. The advantages of the suggested technique are illustrated by the results of calculations on the ground and excited states of the difluorodioxirane (CF2O2) molecule at the second‐order generalized Van Vleck perturbation theory (GVVPT2) level. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Fast and accurate evaluation of three‐center, two‐electron Coulomb, hybrid, and three‐center nuclear attraction integrals over Slater‐type orbitals using the SD transformation
Authors: Berlu Lilian , Safouhi Hassan , Hoggan Philip 
Published: June 2004

AbstractIn this work, Slater‐type atomic orbitals (STOs) are expanded over B functions to exploit the compact Fourier transform of these functions. The analytic representations of three‐center nuclear attraction integrals and multicenter bielectronic integrals over B functions involve semiinfinite highly oscillatory integrals, which can be transformed into infinite series. These integrals must be evaluated precisely and quickly. This work describes an efficient method for the evaluation of these integrals based on the nonlinear SD transformation, recently developed by Safouhi. The SD method was applied to multicenter integrals over B functions, and it is shown that this method is highly efficient compared with alternatives previously used. The SD approach should lead to a definitive suite of ab initio Slater software. The convergence properties were analyzed and they showed that the approximations obtained using the SD approach converge to the exact values of the semiinfinite integrals without any constraint. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
First‐principles analysis for the optical absorption spectra of metal ions in solids
Authors: Ishii Takugo , Ogasawara Kazuyoshi , Adachi Hirohiko , Burmester Philipp , Huber Günter 
Published: June 2004

AbstractThe authors developed a general first‐principles method for the direct calculation of multiplet structures. The method is a configuration interaction (CI) method combined with a general cluster method based on density functional theory. The present version of the method is based on a fully relativistic framework in which four‐component wave functions are handled. The calculations run independently of the semiempirical crystal field and ligand field theories, which have been the only the methods to analyze the absorption spectra involving the multiplet structures of transition metal and rare‐earth ion centers. One application of the present method is the analyses of the absorption spectra of solid‐state laser crystals. In this article, the authors focus on the multiplet structures originating from the f–f transition of Eu3+ ion in solids. In Eu3+‐doped Y2O3, the overall electronic structure is shown in agreement with the experimentally known absorption spectrum. A comparison of the multiplet structures between Eu3+ and Sm2+ ions is also shown. Although they have the same 4f6 electron configuration, the electronic structures showed different energy positions, and the tendency well agreed with that observed in experimentally known absorption spectra. In the one‐electron molecular orbital energies, the energies of Sm 4f levels were higher than those of Eu 4f levels. The difference is considered to originate from the difference in electron–nucleus attractive potential. The molecular orbitals of Eu 4f levels showed obvious mixing with O 2p orbitals, but those of Sm 4f levels did not. The calculated multiplet energies of Sm2+ were systematically smaller than those of Eu3+. The smaller multiplet energies originated from the smaller values of two‐electron integrals, indicating the relatively larger distribution of Sm 4f orbitals than those of Eu. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Exact analytic total energy functional for Hooke's atom generated by local‐scaling transformations
Authors: Ludeña Eduardo V. , Gómez Daniel , Karasiev Valentin , Nieto Pedro 
Published: June 2004

AbstractAn analytic closed form for the total energy density functional for Hooke's atom—an artificial two‐electron system with harmonic electron–nuclear and Coulombic electron–electron interaction terms—has been constructed by means of local‐scaling transformations. This is the first time that an exact density functional is obtained for a quantum mechanical many‐electron system containing electron correlation. The density‐dependent functional advanced in the present work is strictly variational: It yields the exact value of the total energy of Hooke's atom at the exact density and upper bounds for all other densities. Although the functional is not “universal” it contains the density‐dependent term ρ5/3 in the kinetic energy expression and an infinite sum of universal terms of the type ρ(l+4)/3, for l = 0, 1, … ∞, in the electron–electron energy. In all cases, these density‐dependent terms are multiplied by their corresponding enhancement factors F5/3(r) and {F(r)} that contain system‐specific information. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Effect of rotations on the generation of coherent internal molecular motion
Authors: Hervé Stephen , Le Quéré Frédéric , Marquardt Roberto 
Published: June 2004

AbstractWe discuss the quantum dynamics of the excitation of a diatomic molecule in the presence of external force fields and the general role of orientation on the manipulation of molecular structure. We review the dynamics of the HF molecule in the presence of a static electric field during and after coherent infrared radiation. The time‐dependent dynamics is induced by infrared multiphoton excitation and the time evolution of the rovibrational wave packet is calculated in configuration space. The coherent motion of rotational wave packets obtained from orientation in a static field is compared with the motion of rotational coherent states. Values are given for static field strengths needed to orient molecules such that their internal dynamics can be described by simplified, purely vibrational models. The results are discussed in comparison with the orientation of adsorbed molecules on metal surfaces. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004