bluuebunny/crossref_metadata_2025_split huggingface dataset:
Projection patterns of posterior dorsal unpaired median neurons of the locust subesophageal ganglion
Authors: Bräunig Peter , Burrows Malcolm 
Published: August 2004

AbstractSix neurons in a group of dorsal unpaired median (DUM) neurons with cell bodies in the posterior part—maxillary and labial neuromeres—of the subesophageal ganglion of locusts have two axons each that descend into both the left and the right halves of the ganglia of the ventral nerve cord. None of the neurons has peripheral axons, so they are interneurons. Electrophysiology shows that the axons of at least four neurons project to the terminal abdominal ganglion to which they conduct spikes at a velocity of 0.5–0.6 m · second–1. In the somata, the spikes have a smaller amplitude and briefer duration at half height than the spikes of thoracic, efferent DUM neurons. Each neuron has bilaterally symmetrical branches within the subesophageal ganglion and in the thoracic ganglia. On the basis of the specific patterns of branches, and the neuropiles, tracts, and commissures in which they occur, three types of neurons (DUM SD 1–3) can be recognized. DUM SD 1 and 3 project to ventral regions of neuropile in the thoracic ganglia in which the efferent DUM neurons of these ganglia have no branches. DUM SD 2 projects to dorsal neuropiles. The projection patterns of these putatively octopaminergic neurons suggest that they could be the source of the octopaminergic modulation of networks underlying sensory processing and motor pattern generation within these ganglia. Within this group of posterior DUM neurons, two additional cells were stained that have axons ascending to the brain. J. Comp. Neurol. 478:164–175, 2004. © 2004 Wiley‐Liss, Inc.
Ten Years of Plasma Crystals ‐ from ICPIG (Bochum) to ICPIG (Greifswald)
Authors: Morfill G. E. , Ivlev A. V. , Khrapak S. A. , Klumov B. A. , Rubin‐Zuzic M. , Konopka U. , Thomas H. M. 
Published: August 2004

AbstractThe current status of experimental and theoretical research into plasma crystals is reviewed. We start with the derivation of a generalized phase diagram for complex plasmas, followed by crystal structures observed in laboratory experiments and in space under microgravity conditions, and finish with an outlook into developing areas — homogeneous nucleation and nonequilibrium crystallization. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of Stationary Plasma Thrusters
Authors: Hagelaar G. J. M. , Bareilles J. , Garrigues L. , Boeuf J.‐P. 
Published: August 2004

AbstractThe discharge in stationary plasma thrusters (SPTs) can be simulated by hybrid discharge models, describing neutrals and ions by the particle in cell technique and electrons by fluid equations, and deducing the electric field from the quasi‐neutrality condition. We discuss the principles, challenges, and benefits of these SPT models. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rapid review of liquid‐based smears as a quality control measure
Authors: Henderson Sheryl , Stevens Mark , Walker Todd 
Published: August 2004

AbstractThe objective of this study was to investigate the effectiveness of a standardized method of rapid review (RR) of monolayer preparations for the identification of abnormalities, the presence of an endocervical component and infectious agents. A total of 200 ThinPrep (Cytyc, Boxborough, MA) slides representing the spectrum of abnormalities commonly encountered in cervical/vaginal cytologic specimens was retrieved from archive. The study set comprised 129 cases within normal limits (WNL); 36 low‐grade epithelial abnormalities (LGEA); 28 high‐grade epithelial abnormalities (HGEA), including 2 endocervical adenocarcinomas in situ (AIS) and 7 carcinomas. Eighteen false negative (FN) cases were also included for study. Originally missed on initial review, these cases were found to be abnormal on quality control review (17 LGEA; 1 AIS). Commonly encountered infectious agents were represented and included Candida albicans, Trichomonas vaginalis, herpes simplex virus, and Actinomyces. The slides were reviewed using a standardized method of RR (turret technique, for 60 sec) by three experienced screeners masked to the original reference diagnosis. Median sensitivity for LGEA was 70% (range, 67–72%); HGEA, 69% (range, 54–80%); and FN, 65% (range, 56–78%). Specificity remained high, median specificity for LGEA was 95%; HGEA, 97%; and FN, 100%. There was no significant overcalling of any diagnostic category. The chi‐square test at P < 0.05 showed no significant difference between RR and full manual rescreen of the ThinPrep smears in this study. While no statistical difference was proven, the sensitivity measurements for all categories of abnormality were moderate due to the high proportion of atypical cases included into the study set. Abnormalities on the monolayer preparations frequently displayed fewer, smaller groups of disaggregated cells with rounded cytoplasmic outlines that were difficult to discern on RR. Interobserver variation was noted. Monolayers with a paucity of diagnostic cells and those displaying subtle nuclear atypia were often overlooked. Diagn. Cytopathol. 2004;31:141–146. © 2004 Wiley‐Liss, Inc.
The sources of hospital cost variability
Authors: Dormont Brigitte , Milcent Carine 
Published: August 2004

AbstractHospital heterogeneity is a major issue in defining a reimbursement system. If hospitals are heterogeneous, it is difficult to distinguish which part of the differences in costs is due to cost containment efforts and which part cannot be reduced, because it is due to other unobserved sources of hospital heterogeneity. In this paper, we apply an econometric approach to analyse hospital cost variability. We use a nested three‐dimensional database (stays‐hospitals‐years) in order to explore the sources of variation in hospital costs, taking into account unobservable components of hospital cost heterogeneity. The three‐dimensional structure of our data makes it possible to identify transitory and permanent components of hospital cost heterogeneity. Econometric estimates are performed on a sample of 7314 stays for acute myocardial infarction (AMI) observed in 36 French public hospitals over the period 1994–1997. Transitory unobservable hospital heterogeneity is far from negligible: its estimated standard error is about 50% of the standard error we estimate for cost variability due to permanent unobservable heterogeneity between hospitals. Copyright © 2004 John Wiley & Sons, Ltd.
Hildebrand and Hansen solubility parameters from Molecular Dynamics with applications to electronic nose polymer sensors
Authors: Belmares M. , Blanco M. , Goddard W. A. , Ross R. B. , Caldwell G. , Chou S.‐H. , Pham J. , Olofson P. M. , Thomas Cristina 
Published: August 2004

AbstractWe introduce the Cohesive Energy Density (CED) method, a multiple sampling Molecular Dynamics computer simulation procedure that may offer higher consistency in the estimation of Hildebrand and Hansen solubility parameters. The use of a multiple sampling technique, combined with a simple but consistent molecular force field and quantum mechanically determined atomic charges, allows for the precise determination of solubility parameters in a systematic way (σ = 0.4 hildebrands). The CED method yields first‐principles Hildebrand parameter predictions in good agreement with experiment [root‐mean‐square (rms) = 1.1 hildebrands]. We apply the CED method to model the Caltech electronic nose, an array of 20 polymer sensors. Sensors are built with conducting leads connected through thin‐film polymers loaded with carbon black. Odorant detection relies on a change in electric resistivity of the polymer film as function of the amount of swelling caused by the odorant compound. The amount of swelling depends upon the chemical composition of the polymer and the odorant molecule. The pattern is unique, and unambiguously identifies the compound. Experimentally determined changes in relative resistivity of seven polymer sensors upon exposure to 24 solvent vapors were modeled with the CED estimated Hansen solubility components. Predictions of polymer sensor responses result in Pearson R2 coefficients between 0.82 and 0.99. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1814–1826, 2004
Macromolecular crowding in biological systems: hydrodynamics and NMR methods
Authors: Bernadó Pau , de la Torre José García , Pons Miquel 
Published: August 2004

AbstractMost biologically relevant environments involve highly concentrated macromolecular solutions and most biological processes involve macromolecules that diffuse and interact with other macromolecules. Macromolecular crowding is a general phenomenon that strongly affects the transport properties of macromolecules (rotational and translational diffusion) as well as the position of their equilibria. NMR methods can provide information on molecular interactions, as well as on translational and rotational diffusion. In fact, rotational diffusion, through its determinant role in NMR relaxation, places a practical limit on the systems that can be studied by NMR. While in dilute solutions of non‐aggregating macromolecules this limit is set by macromolecular size, in crowded solutions excluded volume effects can have a strong effect on the observed diffusion rates. Hydrodynamic theory offers some insight into the magnitude of crowding effects on NMR observable parameters. Copyright © 2004 John Wiley & Sons, Ltd.
Neutron scattering measurements of intact cells show changes after heat shock consistent with an increase in molecular crowding
Authors: Ford Robert C. , Ruffle Stuart V. , Michalarias Ilias , Beta Ilir , Ramirez‐Cuesta Anibal J. , Li Jichen 
Published: August 2004

AbstractMolecular crowding has been shown to be important in many cellular processes. The crowded environment in the cell results in a significant proportion of the cellular water being in contact with macromolecules such as proteins and DNA. These interfacial water molecules show a reduced dynamic motion that has been observed with isolated macromolecules using several biophysical techniques. Previously we investigated the inelastic neutron scattering properties of water closely associated with isolated biomolecules, and showed that interfacial water is strongly perturbed, as judged by its energy transfer spectrum. Here we have probed living cells using inelastic and quasielastic neutron scattering. We have found that mild heat stress (‘heat shock’), which causes some proteins to become unfolded in the cell, results in changes in the inelastic neutron scattering in the librational region (45–130 meV). Heat shock also causes a narrowing of the quasielastic scattering peak. These changes can be understood in terms of an increase in the proportion of interfacial water molecules, and a net reduction in proton dynamics. Copyright © 2004 John Wiley & Sons, Ltd.
A comprehensive modeling study of hydrogen oxidation
Authors: Ó Conaire Marcus , Curran Henry J. , Simmie John M. , Pitz William J. , Westbrook Charles K. 
Published: August 2004

AbstractA detailed kinetic mechanism has been developed to simulate the combustion of H2/O2 mixtures, over a wide range of temperatures, pressures, and equivalence ratios. Over the series of experiments numerically investigated, the temperature ranged from 298 to 2700 K, the pressure from 0.05 to 87 atm, and the equivalence ratios from 0.2 to 6.Ignition delay times, flame speeds, and species composition data provide for a stringent test of the chemical kinetic mechanism, all of which are simulated in the current study with varying success. A sensitivity analysis was carried out to determine which reactions were dominating the H2/O2 system at particular conditions of pressure, temperature, and fuel/oxygen/diluent ratios. Overall, good agreement was observed between the model and the wide range of experiments simulated. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 603–622, 2004
Synthesis and characterization of macroinitiator‐amino terminated PEG and poly(γ‐benzyl‐L‐glutamate)‐PEO‐poly(γ‐benzyl‐L‐glutamate) triblock copolymer
Authors: Wang Lianyong , Wang Shenguo , Bei Jian zhong 
Published: August 2004

AbstractMacroinitiator‐amino terminated poly(ethylene glycol) (PEG) (NH2‐PEO‐NH2) was prepared by converting both terminal hydroxyl groups of PEG to more reactive primary amino groups. The synthetic route involved reactions of chloridize, phthalimide and finally hydrazinolysis. Furthermore, poly(γ‐benzyl‐L‐glutamate)‐poly(ethylene oxide)‐poly(γ‐benzyl‐L‐glutamate) (PBLG‐PEO‐PBLG) triblock copolymer was synthesized by polymerization of γ‐benzyl‐L‐glutamate N‐carboxyanhydride (Bz‐L‐GluNCA) using NH2‐PEO‐NH2 as macroinitiator. The resultant NH2‐PEO‐NH2 and triblock copolymer were characterized by FT‐IR, 1H‐NMR and gel permeation chromatography (GPC) techniques. The results demonstrated that the degree of amination of the NH2‐PEO‐NH2 could be up to 1.95. The molecular weight of the PBLG‐PEO‐PBLG triblock copolymer could be adjusted easily by controlling the molar ratio of Bz‐L‐Glu NCA to the macroinitiator NH2‐PEO‐NH2. Copyright © 2004 John Wiley & Sons, Ltd.
Novel epoxy compositions for vibration damping applications
Authors: Ratna D. , Manoj N. R. , Chandrasekhar L. , Chakraborty B. C. 
Published: August 2004

AbstractThree epoxy compositions have been developed by using polyether amine hardeners having varying chain lengths of polyethers. Unlike normal epoxies, the compositions show low glass transition temperatures (0–45°C). Dynamic mechanical analysis and time–temperature superposition of the isotherms indicate that they have broad and high loss factor values over broad frequency and temperature ranges suggesting their application as viscoelastic materials in constrained layer damping of structural vibrations. Copyright © 2004 John Wiley & Sons, Ltd.
Micellar charge effects as mechanistic criteria in spontaneous hydrolyses of acid chlorides
Authors: Bunton Clifford A. 
Published: August 2004

AbstractReaction rates in aqueous micelles, treated in terms of a pseudophase model, depend on transfer equilibria between water and micelles and rate constants in each pseudophase. Rate constants of spontaneous reactions of fully micellar‐bound substrates are independent of transfer and are those in the micellar pseudophase. They depend on its properties as a reaction region and the sensitivity of the reaction to medium effects. For a wide range of spontaneous reactions there are simple relationships between rate constants and properties of the micellar interfacial region, e.g. apparent polarity and head‐group charge, which depend on the reaction mechanism. Aqueous micelles inhibit nucleophilic substitutions at alkyl centers, but rate constants, k+, in cationic micelles are higher than those, k−, in anionic micelles for SN2 reactions and lower for SN1 reactions. Except for nitro derivatives, hydrolyses of substituted benzoyl chlorides are micellar inhibited and k+/k−≈18 for nitro derivative and ca 0.04 for 4‐OMe and Me derivatives, indicating different extents of bond making and breaking in the transition state, but there is no evidence of rate‐limiting dissociation in hydrolyses of the latter. For hydrolyses of substituted benzenesulfonyl chlorides, values of k+/k− decrease from 21 for the 4‐NO2 derivative to 1.1 for the 4‐OMe derivative, indicating dominant bond making. These mechanism‐related charge effects are ascribed to charge asymmetries at micelle–water interfaces and zwitterionic sulfobetaine micelles behave very similarly to cationic micelles in these hydrolyses. Copyright © 2004 John Wiley & Sons, Ltd.
Acid–base behavior of triazoleporphyrazines in proton‐donating media
Authors: Khelevina O. G. , Ferro V. R. , Islyaikin M. K. , Veselkova E. A. , Stryapan M. G. , de la Vega J. M. García 
Published: August 2004

AbstractThe acid–base properties of some peripheral substituted triazoleporphyrazines in proton‐donating media with poor‐donating character were experimentally studied. The substitution of one pyrrole moiety in the porphyrazine‐like compounds by one triazole ring in the triazoleporphyrazines leads to an increase in the basicity. The protonation of the triazoleporphyrazines results in a hypsochromic shift of the Q‐bands in the UV–visible spectra. A DFT study of some selected structural models of the unsubstituted triazoleporphyrazine shows that the protonation strongly influences on the molecular electron structure of this compound and that it occurs preferentially through the nitrogen atom located at position 4 of triazole ring. The protonation through the other basic centers (the triazoleporphyrazine is a multicenter conjugated base) leads to different protonated forms which differ notably in their aromatic character. Therefore, this compound could be considered an intramolecular switch of aromaticity. Copyright © 2004 John Wiley & Sons, Ltd.
Layered coding for satellite‐plus‐terrestrial multipath correlated fading channels
Authors: Levissianos A. , Metaxas G. , Dimitriou N. , Polydoros A. 
Published: August 2004

AbstractThis paper introduces two alternative layered‐coding (LC) structures suitable for a combination of a geostationary (GEO) satellite and a terrestrial system providing multicasting multimedia services. Both schemes include a RAKE receiver and their performance results are presented under realistic satellite and terrestrial channel conditions. The structures are based on mapping the coded bits either onto 8‐PSK symbols or onto QPSK symbols. The LC parameters (such as the interleaver design and the convolutional encoder structures) are analysed and their effect on performance is quantified, especially in cases of highly correlated channels (low vehicular speeds). The various impairments that are associated to the transmission through both terrestrial and satellite correlated fading channels will be taken into account and link level performance results as well as a complexity discussion will be presented. Copyright © 2004 John Wiley & Sons, Ltd.
Formation and Crystal Structure of [(F5TeOXe)+·SO2ClF][Sb(OTeF5)6‐]
Authors: Ulferts Peer , Seppelt Konrad 
Published: August 2004

AbstractXe(OTeF5)2 reacts with Sb(OTeF5)3 under the formation of [Xe2(OTeF5)3]+[Sb(OTeF5)6]‐. From SO2ClF solution a yellow solvate [F5TeOXe]+·SO2ClF· [Sb(OTeF5)6]‐ is formed with the crystal data: a = 1028.1(1), b = 1040.9(1), c = 1780.2(3) pm, α = 98.07(1), β = 97.68(1), γ = 105.82(1)°, space group $P {\bar 1}$. The O‐Xe···O fragment is essentially linear (176.1(2)°), and the two Xe‐O distances are quite different 197.1(4) and 242.6(4) pm.
Depensation, probability of fertilization, and the mating system of Atlantic cod (Gadus morhua L.)
Authors: Rowe Sherrylynn , Hutchings Jeffrey A. , Bekkevold Dorte , Rakitin Ana 
Published: August 2004

AbstractAtlantic cod (Gadus morhua L.) have been severely overexploited and are currently at historic population lows, having declined 90% in the North Sea and 99% off northeast Newfoundland in recent decades. Slow rates of recovery and continuing declines may be attributable to depensation, defined as a reduction in per capita growth rate concomitant with reduced population size. Several potential causes of depensation relate to low mating success and consequent reduced production of offspring. We explore the empirical basis of one of these in Atlantic cod using egg fertilization and male abundance data obtained from 21 experimental populations generated by three independent research programmes. We find support for the hypotheses that (a) fertilization rate declines with abundance and (b) variance in fertilization rate increases as population size declines. The former identifies one potential mechanism underlying depensation in Atlantic cod. The latter has negative genetic consequences for effective population size (Ne), resulting in a decline in the ratio of Ne to census population size (Ne/Nc) with declining abundance. Our results may have general implications for the conservation biology of broadcast-spawning marine fish, particularly those with mating systems similar to that of Atlantic cod.
DWE: Discriminating Word Enumerator
Authors: Sumazin Pavel , Chen Gengxin , Hata Naoya , Smith Andrew D. , Zhang Theresa , Zhang Michael Q. 
Published: August 2004

AbstractMotivation: Tissue-specific transcription factor binding sites give insight into tissue-specific transcription regulation.Results: We describe a word-counting-based tool for de novo tissue-specific transcription factor binding site discovery using expression information in addition to sequence information. We incorporate tissue-specific gene expression through gene classification to positive expression and repressed expression. We present a direct statistical approach to find overrepresented transcription factor binding sites in a foreground promoter sequence set against a background promoter sequence set. Our approach naturally extends to synergistic transcription factor binding site search.We find putative transcription factor binding sites that are overrepresented in the proximal promoters of liver-specific genes relative to proximal promoters of liver-independent genes. Our results indicate that binding sites for hepatocyte nuclear factors (especially HNF-1 and HNF-4) and CCAAT/enhancer-binding protein (C/EBPβ) are the most overrepresented in proximal promoters of liver-specific genes. Our results suggest that HNF-4 has strong synergistic relationships with HNF-1, HNF-4 and HNF-3β and with C/EBPβ.Availability: Programs are available for use over the Web at http://rulai.cshl.edu/tools/dweContact: ps@cs.pdx.edu; mzhang@cshl.eduSupplementary information: Data and omitted results are available at http://rulai.cshl.edu/tools/dwe/supp
SABmark—a benchmark for sequence alignment that covers the entire known fold space
Authors: Van Walle Ivo , Lasters Ignace , Wyns Lode 
Published: August 2004

AbstractSummary: The Sequence Alignment Benchmark (SABmark) provides sets of multiple alignment problems derived from the SCOP classification. These sets, Twilight Zone and Superfamilies, both cover the entire known fold space using sequences with very low to low, and low to intermediate similarity, respectively. In addition, each set has an alternate version in which unalignable but apparently similar sequences are added to each problem.Availability: SABmark is available from http://bioinformatics.vub.ac.beContact: ivwalle@vub.ac.be