bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined Ventricular Systolic and Arterial Stiffening in Patients With Heart Failure and Preserved Ejection Fraction
Authors: Kawaguchi Miho , Hay Ilan , Fetics Barry , Kass David A.
Published: February 2003

Background—

Heart failure with preserved ejection fraction (HF-nlEF) is common in aged individuals with systolic hypertension and is frequently ascribed to diastolic dysfunction. We hypothesized that such patients also display combined ventricular-systolic and arterial stiffening that can exacerbate blood pressure lability and diastolic dysfunction under stress.

Methods and Results—

Left ventricular pressure-volume relations were measured in patients with HF-nlEF (n=10) and contrasted with asymptomatic age-matched (n=9) and young (n=14) normotensives and age- and blood pressure-matched controls (n=25). End-systolic elastance (stiffness) was higher in patients with HF-nlEF (4.7±1.5 mm Hg/mL) than in controls (2.1±0.9 mm Hg/mL for normotensives and 3.3±1.0 mm Hg/mL for hypertensives;
P
<0.001). Effective arterial elastance was also higher (2.6±0.5 versus 1.9±0.5 mm Hg/mL) due to reduced total arterial compliance; the latter inversely correlated with end-systolic elastance (
P
=0.0001). Body size and stroke volumes were similar and could not explain differences in ventricular-arterial stiffening. HF-nlEF patients also displayed diastolic abnormalities, including higher left ventricular end-diastolic pressures (24.3±4.6 versus 12.9±5.5 mm Hg), caused by an upward-shifted diastolic pressure-volume curve. However, isovolumic relaxation and the early-to-late filling ratio were similar in age- and blood pressure-matched controls. Ventricular-arterial stiffening amplified stress-induced hypertension, which worsened diastolic function, and predicted higher cardiac energy costs to provide reserve output.

Conclusion—

Patients with HF-lnEF have systolic-ventricular and arterial stiffening beyond that associated with aging and/or hypertension. This may play an important pathophysiological role by exacerbating systemic load interaction with diastolic function, augmenting blood pressure lability, and elevating cardiac metabolic demand under stress.
Central Sleep Apnea in Left Ventricular Dysfunction
Authors: Lanfranchi Paola A. , Somers Virend K. , Braghiroli Alberto , Corra Ugo , Eleuteri Ermanno , Giannuzzi Pantaleo
Published: February 2003

Background—

The prevalence and characteristics of sleep-disordered breathing in patients with asymptomatic left ventricular (LV) dysfunction are unknown. Therefore, we evaluated the prevalence of sleep-disordered breathing in patients with LV dysfunction without overt heart failure and tested the hypothesis that sleep-disordered breathing is linked to greater hemodynamic and autonomic impairment.

Methods and Results—

We studied 47 patients with LV ejection fractions ≤40% without any history of heart failure. Central sleep apnea (CSA), as defined by an apnea-hypopnea index ≥15/h, was present in 26 patients (55%), 17 (36%) of whom had severe CSA (apnea-hypopnea index ≥30/h). Obstructive sleep apnea was evident in 5 patients (11%). The prevalence and severity of CSA were higher in patients with ischemic cardiomyopathy than in patients with nonischemic cardiomyopathy (
P
<0.05). Exercise tolerance and echocardiographic indices of systolic and diastolic function were similar in patients without CSA, with mild CSA, and with severe CSA. Heart rate variability was markedly depressed in patients with CSA (
P
<0.05). Patients with severe CSA also had a higher incidence of nonsustained ventricular tachycardia (
P
=0.05).

Conclusions—

CSA is highly prevalent in patients with asymptomatic LV dysfunction. The severity of CSA may not be related to the severity of hemodynamic impairment. Severe CSA is associated with impaired cardiac autonomic control and with increased cardiac arrhythmias.
Generating CTLs against the subdominant Epstein-Barr virus LMP1 antigen for the adoptive immunotherapy of EBV-associated malignancies
Authors: Gottschalk Stephen , Edwards Oliver L. , Sili Uluhan , Huls M. Helen , Goltsova Tatiana , Davis Alan R. , Heslop Helen E. , Rooney Cliona M.
Published: February 2003

The Epstein-Barr virus (EBV)–encoded LMP1 protein is expressed in EBV-positive Hodgkin disease and is a potential target for cytotoxic T-lymphocyte (CTL) therapy. However, the LMP1-specific CTL frequency is low, and so far the generation of LMP1-specific CTLs has required T-cell cloning. The toxicity of LMP1 has prevented the use of dendritic cells (DCs) for CTL stimulation, and we reasoned that an inactive, nontoxic LMP1 mutant (ΔLMP1) could be expressed in DCs and would enable the activation and expansion of polyclonal LMP1-specific CTLs. Recombinant adenoviral vectors expressing LMP1 or ΔLMP1 were tested for their ability to transduce DCs. LMP1 expression was toxic within 48 hours whereas high levels of ΔLMP1 expression were achieved with minimal toxicity. ΔLMP1-expressing DCs were able to reactivate and expand LMP1-specific CTLs from 3 healthy EBV-seropositive donors. LMP1-specific T cells were detected by interferon-γ (IFN-γ) enzyme-linked immunospot assay (ELISPOT) assays using the HLA-A2–restricted LMP1 peptide, YLQQNWWTL (YLQ). YLQ-specific T cells were undetectable (less than 0.001%) in donor peripheral blood mononuclear cells (PBMCs); however, after stimulation the frequency increased to 0.5% to 3.8%. Lysis of autologous target cells by CTLs was dependent on the level of LMP1 expression. In contrast, the frequency of YLQ-specific CTLs in EBV-specific CTLs reactivated and expanded using lymphoblastoid cell lines was low and no LMP1-specific cytotoxic activity was observed. Thus, ΔLMP1 expression in DCs is nontoxic and enables the generation of LMP1-specific CTLs for future adoptive immunotherapy protocols for patients with LMP1-positive malignancies such as EBV-positive Hodgkin disease. Targeting LMP1 in these malignancies may improve the efficacy of current adoptive immunotherapy approaches.
A method for portfolio choice
Authors: Elliott Robert , Hinz Juri
Published: February 2003

This paper shows how one can use the theory of hidden Markov models for portfolio optimization. We illustrate our method by a ball and urn experiment. An application to historical data is examined. Copyright © 2003 John Wiley & Sons, Ltd.
Laser‐induced fluorescence as a powerful detection tool for capillary electrophoretic analysis of heparin/heparan sulfate disaccharides
Authors: Militsopoulou Maria , Lecomte Céline , Bayle Christopher , Couderc Francois , Karamanos Nikos K.
Published: February 2003

In quest for high sensitivities necessary for determining the disaccharide composition of heparin/heparan sulfate present in trace amounts in biologic samples, an ultrahighly sensitive capillary electrophoresis (CE) method using laser‐induced fluorescence (LIF) detection was developed. Heparin/heparan sulfate‐derived Δ‐disaccharides were derivatized with the fluorophore 2‐aminoacridone and resolved by a reversed‐polarity CE method. Estimation of the limit of detection in concentration term and limit of quantitation showed that LIF detection of AMAC‐derivatives of Δ‐disaccharides resulted in 27–744 times higher sensitivity as compared to those detected by UV at 255 nm. These data suggest that CE‐LIF is a powerful tool to quantify minute amounts of heparin/heparan sulfate disaccharides. Copyright © 2003 John Wiley & Sons, Ltd.
Specific determination of unbound oxacillin in protein solution with cefoperazone by high‐performance frontal analysis with chemiluminescence detection
Authors: Li Famei , Qiao Mingxi , Guo Xingjie
Published: February 2003

Unbound oxacillin concentrations in human serum albumin (HSA) solutions in the presence or absence of cefoperazone were determined using high‐performance frontal analysis coupled with chemiluminescence detection (HPFA‐CL). The HPFA was performed on an ISRP column with 67 mM potassium phosphate buffer of pH 7.4 and ionic strength of 0.17 as the mobile phase. The luminol–H2O2–Co2+ system was employed in the chemiluminescence detection. The detection was highly specific for oxacillin in the presence of cefoperazone. Although both drugs in HSA solutions co‐eluted in the same region in HPFA, cefoperazone did not interfere with the determination of unbound concentration of oxacillin. In the solution of 100 µM HSA and 11.33 µM oxacillin the bound percentage of oxacillin to HSA was estimated as 80.5%. Addition of 30.98 µM cefoperazone into the HSA‐equilibrated solution produced little effect on the protein binding of oxacillin. In the presence of 154.9 µM cefoperazone, however, the bound percentage of oxacillin was significantly reduced. This specific method could be applied to the investigation of drug‐drug interaction in protein binding. Copyright © 2003 John Wiley & Sons, Ltd.
Iron Twin‐Coronet Porphyrins as Models of Myoglobin and Hemoglobin: Amphibious Electrostatic Effects of Overhanging Hydroxyl Groups for Successful CO/O2 Discrimination
Authors: Tani Fumito , Matsu‐ura Mikiya , Ariyama Kiyoko , Setoyama Toshikazu , Shimada Takayuki , Kobayashi Shinjiro , Hayashi Takashi , Matsuo Takashi , Hisaeda Yoshio , Naruta Yoshinori
Published: February 2003

Inspired by the observation of polar interactions between CO and O2 ligands and the peptide residues at the active site of hemoglobin and myoglobin, we synthesized two kinds of superstructured porphyrins: TCP‐IM, which contains a linked imidazole ligand, and TCP‐PY, which contains a linked pyridine ligand, and examined the thermodynamic, kinetic, and spectroscopic (UV/Vis, IR, NMR, and resonance Raman) properties of their CO and O2 complexes. On both sides of each porphyrin plane, bulky binaphthyl bridges form hydrophobic cavities that are suitable for the binding of small molecules. In the proximal site, an imidazole or pyridine residue is covalently fixed and coordinates axially to the central iron atom. In the distal site, two naphtholic hydroxyl groups overhang toward the center above the heme. The CO affinities of TCPs are significantly lower than those of other heme models. In contrast, TCPs have moderate O2 binding ability. Compared with reported model hemes, the binding selectivity of O2 over CO in TCP‐IM and TCP‐PY complexes is greatly improved. The high O2 selectivity of the TCPs is mainly attributable to a low CO affinity. The comparison of kon(CO) values of TCPs with those of unhindered hemes indicates the absence of steric hindrance to the intrinsically linear CO coordination to FeII in TCP‐IM and TCP‐PY. The abnormally large koff(CO) values are responsible for the low CO affinities. In contrast, koff(O2) of TCP‐PY is smaller than those of other pyridine‐coordinated model hemes. For the CO adducts of TCPs, unusually low ν(FeCO) and unusually high ν(CO) frequencies are observed. These results can be ascribed to decreased back‐bonding from the iron atom to the bound CO. The lone pairs of the oxygen atoms of the hydroxyl groups prevent back‐bonding by exertion of a strong negative electrostatic interaction. On the other hand, high ν(FeO2) frequencies are observed for the O2 adducts of TCPs. In the resonance Raman (RR) spectrum of oxy‐TCP‐IM, we observed simultaneous enhancement of the FeO2 and OO stretching modes. Furthermore, direct evidence for hydrogen bonding between the hydroxyl groups and bound dioxygen was obtained by RR and IR spectroscopy. These spectroscopic data strongly suggest that O2 and CO binding to TCPs is controlled mainly by the two different electrostatic effects exerted by the overhanging OH groups: destabilization of CO binding by decreasing back‐bonding and stabilization of O2 binding by hydrogen bonding.
Swelling and Shrinking of Polyelectrolyte Microcapsules in Response to Changes in Temperature and Ionic Strength
Authors: Gao Changyou , Leporatti Stefano , Moya Sergio , Donath Edwin , Möhwald Helmuth
Published: February 2003

Swelling and shrinking of polyelectrolyte microcapsules consisting of poly(styrene sulfonate, sodium salt) (PSS) and poly(diallyldimethyl ammonium) chloride (PDADMAC) multilayers have been observed in response to temperature and electrolyte exposure, respectively. Heat‐induced capsule swelling and capsule wall volume reduction were observed by confocal laser scanning microscopy (CLSM) and scanning force microscopy (SFM). On the other hand, pronounced shrinking in diameter induced by exposure to an electrolyte was observed in parallel to increases in the thickness of the capsule wall. The estimated wall volume was reduced to two thirds of the control for the salt‐exposed capsules and one half for the salt‐exposed and simultaneously annealed capsules. This reduction in volume was supposedly mainly caused by the compression of the capsule wall due to the ionic screening from the electrolyte. The highly porous microstructure of the multilayers and loosely bound PSS/PDADMAC complex are thought to be responsible for the structure of the PSS/PDADMAC capsules being easily modulated upon annealing and salt‐exposure.
Electrocatalytic Oxidation of Formic Acid at an Ordered Intermetallic PtBi Surface
Authors: Casado‐Rivera Emerilis , Gál Zoltán , Angelo A. C. D. , Lind Cora , DiSalvo Francis J. , Abruña Héctor D.
Published: February 2003

The electrocatalytic oxidation of formic acid at a PtBi ordered intermetallic electrode surface has been investigated using cyclic voltammetry, rotating disk electrode (RDE) voltammetry and differential electrochemical mass spectrometry (DEMS). The results are compared to those at a polycrystalline platinum electrode surface. The PtBi electrode exhibits superior properties when compared to polycrystalline platinum in terms of oxidation onset potential, current density, and a much diminished poisoning effect by CO. Using the RDE technique, a value of 1.4×10−4 cm s−1 was obtained for the heterogeneous charge transfer rate constant. The PtBi surface did not appear to be poisoned when exposed to a CO saturated solution for periods exceeding 0.5 h. The results for PtBi are discussed within the framework of the dual‐path mechanism for the electrocatalytic oxidation of formic acid, which involves formation of a reactive intermediate and a poisoning pathway.
AFM reveals steps in Mn‐Al silicates crystals obtained from melt
Authors: Nicolov M. F. , Woensdregt C. F.
Published: February 2003

Mn3AI2Si3O12 crystals were grown experimentally at atmospheric pressure and at temperatures 1235 °C from a molten stoichiometric mixture of tephroite (Mn2SiO4), γ‐alumina (A1203) and quartz (SiO2) Their habit is identical to that of natural grown Mn3AI2Si3O12 crystals. Using AFM (Atomic Force Mycroscopy) technique are shown the steps of growing crystals.
Crystal structure of 3‐hydroxy methyl 4,6‐dimethoxy‐9‐phenylsulfonyl‐carbazole
Authors: Govindasamy L. , Rajakannan V. , Velmurugan D. , Mohanakrishnan A. K. , Srinivasan P. C.
Published: February 2003

The crystal structure of 3‐Hydroxy methyl 4,6‐dimethoxy‐9‐phenylsulfonyl‐carbazole. (C21H19NO5S) has been determined [CCDC 194425]. The compound crystallizes from methanol in the monoclinic system, space group I2/c, with unit cell parameters: a = 20.498(2), b = 9.258(2), c = 21.866(3)Å, β = 116.450(10)°, Z = 8, V = 3715.2(10)Å3. The crystal structure was solved by direct methods and refined by full‐matrix least squares to a final R‐value of 0.050 with 3508 unique reflections. The planar carbazole ring fragment is inclined at an angle of 79.9(1)° to the phenylsulfonyl group. The sum of the angle about N is 351.6(2)°. The atoms linked to the central hexavalent S atom are arranged in a tetrahedral configuration with the larger deviations in the O‐SO angles [O1‐S‐O2 = 119.7(2)°] and the O1‐S‐N and O2‐S‐N angles [106.1(2) and 106.9(1)°, respectively].
Crystal structure of cis,cis,cis‐1,2‐epoxy‐3,5‐dibromo‐4‐hydroxy tetralin
Authors: Çelik I. , Demirtas I. , Akkurt M. , Erenler R. , Güven K. , Çakmak O.
Published: February 2003

The title compound, C10H8Br2O2, consists of a tetrahydronaphthalene skeleton composed of a six‐membered ring A with arene oxide, monobromo and monohydroxy atoms in cis,cis,cis configuration held in a boat conformation and a six‐membered planar ring B, where the ring B carries monobromo atom. The repulsive interactions between the Br and OH atoms affect the topology of the tetrahydronaphthalene moieties.
A new database for seed oil fatty acids — the database SOFA
Authors: Aitzetmüller Kurt , Matthäus Bertrand , Friedrich Holger
Published: February 2003

In a time of diminishing resources, a better knowledge of nature's biodiversity is important. The plant kingdom contains lipids with an astonishing variety of structures, particularly so in angiosperm seed oils. Lipids as natural products are an exciting field of research. Over many years, the Institute for Chemistry and Physics of Lipids in Münster has collected seed oil fatty acid composition data, which were sorted by plant botanical name. Although this collection contained numerous examples for the occurrence, distribution, and content of fatty acids with unusual structures in various concentrations, they could not be searched for manually. This data collection has now been transferred into an electronically searchable database, offering a variety of search routines. Currently it contains about 110, 000 individual data in 17, 500 sets, relating to more than 7, 000 different plant species. About 500 different fatty acids are listed. The database permits searches for plant species, genera and families, for individual fatty acids and combinations of fatty acids in their seed oils, and for their percentage contents in form of fatty acid composition tables. It also contains literature references and close to 1, 000 unpublished data from analyses carried out by GLC analysis between 1986 and 2002 in the Institute for Chemistry and Physics of Lipids. Most interestingly, fatty acid partial structures or functional groups can also be searched for, yielding the percentage contents of relevant fatty acids, using a specially developed “Delta‐Notation” system. The data on occurrence and distribution of unusual fatty acids in the plant kingdom will be useful in chemistry, botany, search for renewable resources, plant breeding, gene technology or gene transfer and indirectly also for enzyme design. A number of examples for “search” and find operations are given and may help to illustrate the usefulness of the new database.
Conicaquinones A and B, Two Novel Cytotoxic Terpene Quinones from the Mediterranean Ascidian Aplidium conicum
Authors: Aiello Anna , Fattorusso Ernesto , Luciano Paolo , Menna Marialuisa , Esposito Giuseppe , Iuvone Teresa , Pala David
Published: February 2003

Two new unique cytotoxic metabolites, conicaquinones A (1) and B (2), each possessing a 1,1‐dioxo‐1,4‐thiazine ring, were isolated from the Mediterranean ascidian Aplidium conicum. Their structures were established by an extensive spectroscopic analysis. Compounds 1 and 2 exhibited a strong cytotoxicity in vitro against rat glioma cells. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Copper Solid Amalgam Electrodes
Authors: Yosypchuk Bogdan , Novotný Ladislav
Published: February 2003

This work describes the behavior of copper solid amalgam electrodes (CuSAE). The applied potential range has been compared with that of the silver solid amalgam electrode (AgSAE) and the hanging mercury drop electrode (HMDE). In 0.05 M tetraborate buffer the applicable potential range of CuSAE is+0.945 V to −1.75 V excluding −0.2 V to −0.5 V, where the anodic oxidation of copper occurs. CuSAE does not need other than electrochemical pre‐treatment, which has been documented by the evaluated repeatability of eleven voltammetric curves of Cd2+ (0.1 ppm), Pb2+ (0.1 ppm) and Mn2+ (0.5 ppm). The obtained results showed that CuSAE could substitute the solid copper, amalgamed copper or liquid copper amalgam electrodes, and can be applied for the study of systems needing an addition of Cu2+ ions into the measured solution.
Self‐Assembled Monolayers into the 21st Century: Recent Advances and Applications
Authors: Gooding J. Justin , Mearns Freya , Yang Wenrong , Liu Jingquan
Published: February 2003

The modification of an interface on a molecular level with more than one molecular ‘building block' is essentially an example of the ‘bottom–up' fabrication principle of nanotechnology. The fabrication of such integrated molecular systems in electrochemistry has seen rapid progress in recent years via the development of sensing interfaces fabricated using self‐assembled monolayers (SAMs). This review outlines recent advances and applications of self‐assembled monolayers for modifying electrodes with an emphasis on the development of integrated molecular systems. First, some basic issues regarding fabricating integrated molecular systems, such as the role of the surface topography of the electrode and patterning surfaces, are discussed. Subsequently an overview of recent developments in pH, inorganic and bio sensing involving the use of SAMs is given. Finally emerging trends in using molecular building blocks in the fabrication of integrated molecular systems, such as nanotubes, dendrimers and nanoparticles, are reviewed.
The use of barium and strontium abundances in human skeletal tissues to determine their geographic origins
Authors: Burton J. H. , Price T. D. , Cahue L. , Wright L. E.
Published: February 2003

Decades of research show that barium and strontium enter skeletal tissues in proportion to their dietary abundance and, hence, to local environmental levels. Among regions that contrast geologically or climatologically, the environmental abundance of these elements can vary substantially and exceed variation due solely to local dietary differences. Because dental enamel develops during childhood and retains the original levels of these elements, it can provide a chemical signature of the geographic origins of individuals. Copyright © 2003 John Wiley & Sons, Ltd.
Assessing the preservation of biogenic strontium in fossil bones and tooth enamel
Authors: Hoppe K. A. , Koch P. L. , Furutani T. T.
Published: February 2003

Analyses of the strontium isotope ratio (87Sr/86Sr) of vertebrate fossils can provide information about palaeobiological attributes such as habitat use and movement patterns. Diagenetic contaminants can alter the 87Sr/86Sr ratio of fossils, however, complicating palaeobiological interpretations. Several pretreatment protocols have been developed to separate diagenetic contaminants from biogenic Sr. While these methods can remove some diagenetic Sr, it has not been shown that any technique removes all contamination. The extent to which pretreatment removes diagenetic Sr can be quantified through analysis of the 87Sr/86Sr ratios of fossil marine mammal bones and teeth buried in sediments with non‐marine diagenetic 87Sr/86Sr signatures. To do this, we examined Holocene seals recovered from archaeological sites in Greenland and California, as well as a Miocene whale from Maryland. Our results demonstrate that although pretreatment eliminated some contaminants from bone, a large percentage (up to 80%) of diagenetic Sr remained after treatment. In contrast, pretreatment does appear to remove nearly all (≥∼95%) diagenetic Sr from tooth enamel. Copyright © 2003 John Wiley & Sons, Ltd.
Partitioning of unsaturated hydrophilic monomer in microemulsion media monitored by pyrene fluorescence method
Authors: Capek Ignac , Liaw Der‐Jang , Huang Ching‐Cheng
Published: February 2003

The extent of intra‐ and interchain associations of (un)charged water‐soluble monomers in the homogeneous and micellar solutions was studied with steady‐state fluorescence spectroscopy. Fluorescence spectroscopic experiments were performed on uncharged (acryl amide) and charged hydrophilic monomers [zwitterionic 3‐dimethyl(methacryloyloxyethyl)ammonium propane sulfonate (DMAPS), etc.] with pyrene as a probe. In both the homogeneous and micellar solutions, linear Stern–Volmer plots were obtained that implied that the quenching process can be considered as totally dynamic. The Stern–Volmer constant (KSV) for DMAPS decreased with an increasing dielectric constant of solvent and the concentration of simple electrolyte. An abrupt decrease in KSV was observed in the presence of a small amount of anionic emulsifier [below the critical micelle concentration (cmc)]. The dependence of KSV on pH for DMAPS was described by a curve with a maximum at about pH = 7. This was interpreted in terms of segregation of DMAPS and the variation of a optimal microenvironment for the probe and quencher with pH. The quenching rate in the micellar solutions strongly increased above the cmc but was lower than that in the homogeneous solutions. In the micellar solutions (above the cmc), the microenvironment for an interaction between the probe and quencher was suggested to be the whole microdroplet. The dependence of KSV on pH for DMAPS is described by a curve with a maximum at about pH = 9.3. The synergistic effect arises from the segregation of charged quencher molecules within the microdroplets. The complex (or strong interaction) between quencher and additive(s) is supposed to increase the dynamic nature of microdroplets that provides an optimal microenvironment for probe and quencher. A good coemulsifier, however, removes quencher from the interface and creates a barrier for entering monomer (quencher) into the core of micelles; therefore, quenching is depressed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 571–581, 2003
Dynamic, hard and strategic questions: using optimization to answer a marketing resource allocation question
Authors: Graham Alan K. , Ariza Carlos A.
Published: February 2003

For historical reasons, optimization has traditionally been slightly outside the mainstream of system dynamics. However, computer technology has made both quantitative data more abundant and optimization more feasible. At the same time, modelers are encountering real situations and clients with high‐stakes questions that are nearly impossible to answer without optimization—the systems involved are not only dynamic, and not only highly interconnected, but also combinatorially daunting. In particular, corporate marketers currently make allocation decisions impacting billions of dollars of shareholder value on the basis of intuitive “anchor and adjust” strategies, which can be far from optimal. This article presents an anonymized case study of one such situation. The company is in a high‐tech industry undergoing rapid change. The company needed to fashion a go‐to‐market strategy balancing traditional and unfamiliar markets, an important component of which was allocation of marketing resources. Optimization revealed a potential valuation increase of roughly 30 per cent relative to executives' intuitive allocations. Scenario analysis revealed the basic policy direction (more advertising) to be robust, and in the process resolved several traditional conundrums in dealing with adverse events in the marketplace. Copyright © 2003 John Wiley & Sons, Ltd.
On non‐entropy solutions of scalar conservation laws for traffic flow
Authors: Gasser I.
Published: February 2003

We consider traffic flow models described by a scalar conservation law. For realistic equilibrium velocity distributions we show that the entropy condition gives solutions not corresponding to the reality. An alternative condition is formulated which seems to select reasonable solutions. Two examples, the “bump” and the “cluster”, are discussed.
Multiple internal light scattering in polymers
Authors: Harris Robert A. , McClain Wm. Martin
Published: February 2003

We show how the effect of multiple scattering of radiation is incorporated in the theory of polarized light scattering from a dilute polymer solution. We prove that the tensor structure of the scattering amplitude deduced previously is unchanged by the inclusion of this effect. The dependence of the amplitude on polymer quantities is exhibited.
Semiclassical theory of optical rotation near resonance absorption
Authors: Salzman W. R.
Published: February 2003

A recently presented technique is used to derive expressions for the dynamical polarizability α and the optical rotation parameter β which do not diverge at resonant absorption frequencies and nonzero light intensities. The effective α and β are intensity dependent but yield the usual divergent forms in the limit of zero intensity.
Computational tests of the coupled states angular momentum decoupling approximation for NMR spin–lattice relaxation cross sections
Authors: Goldflam Rudolf , Green Sheldon , Kouri Donald J.
Published: February 2003

Recently, Goldflam and Kouri have derived coupled states (CS) expressions for NMR spin–lattice relaxation effective cross sections. In this paper we report computational tests of these expressions for CO, HD, and HCl, each in a He bath, and make comparisons with accurate close coupling (CC) results. The agreement in general is excellent, indicating that the CS method can be used to accurately predict such reorientation effects as occur in spin–lattice relaxation.
An optically pumped molecular bromine laser
Authors: Wodarczyk Francis J. , Schlossberg Howard R.
Published: February 2003

Molecular bromine has been observed to lase when optically pumped on individual vibration–rotation lines. With no dispersive elements in the laser cavity the output consists of several doublets, corresponding to P- and R-branch transitions from the excited (B) state populated by the pump pulse to various vibrational levels of the ground state. The insertion of an intracavity prism causes a single doublet to lase, with a corresponding reduction in output power. In the current experiments the output wavelength was tunable from 550 nm in the green to 750 nm in the red for each transition pumped near 532 nm. The broadband efficiency was a few tenths of a percent, with the single-line output efficiency one-tenth of that. The theoretical gain at 10 torr and 300 K was estimated to be 0.05–0.40 per cm. This system offers a quasicontinuous tunable source of radiation ranging from the visible to 3.5 μm in the infrared.
Characteristic vibrational coupling behavior of intermolecular potentials
Authors: Dougherty Eugene , Rabitz Herschel , Detrich John , Conn Robert
Published: February 2003

Some recently available intermolecular potentials have been investigated and cast into a form suggestive of similar vibrational coupling behavior. The underlying physical factors behind these similarities are discussed. It is argued that a typical potential will exhibit an intermolecular distance(s) at which the vibrational coupling vanishes. It is expected that knowledge of this behavior will be particularly useful in model calculations of vibrationally inelastic collision processes.
Spectra and structure of small ring compounds. XXXVII. Two-dimensional potential surface and barrier to interconversion for silacyclopentane
Authors: Durig J. R. , Natter W. J. , Kalasinsky V. F.
Published: February 2003

The Raman spectrum of gaseous silacyclopentane has been recorded from 25 to 4000 cm−1. The series of Q branches observed at 264.5, 259.9, and 255.3 cm−1 have been assigned as the fundamental and hot bands of the radial vibration of a hindered pseudorotator. A two-dimensional potential surface has been determined and indicates that the interconversion between equivalent twisted forms proceeds through a puckered intermediate. The barrier of 1414 cm−1 is of the same order as that found using a one-dimensional treatment, and the two models are discussed.
A mass spectrometric study of heteronuclear diatomic alkali metal molecules. Dissociation energies and ionization potentials of NaLi, KLi, and NaK.
Authors: Zmbov K. F. , Wu C. H. , Ihle H. R.
Published: February 2003

The gaseous molecules NaLi, KLi, and NaK were studied by equilibrium and electron impact techniques. The dissociation energies of these molecules were determined from the second and the third law enthalpies of various equilibria, and the following values were obtained: D00(NaLi) =20.7±1.5 kcal/mole, D00 KLi) =18.7±1.0 kcal/mole, and D00(NaK) =14.6±1.0 kcal/mole. Electron impact measurements yield values of 4.94±0.10, 4.69±0.10, and 4.57±0.20 eV for the ionization potentials of NaLi, KLi, and NaK molecules, respectively. The results are compared with spectroscopic data and recent theoretical calculations. The relation of these results to the bonding in heteronuclear diatomic alkali metal molecules is discussed.
The relation between orbital SCF energies and total SCF energies in molecules
Authors: Schaad L. J. , Robinson B. H. , Hess B. A.
Published: February 2003

The Hartree–Fock electronic energy of a molecule may be approximated as 1/4 times the sum of orbital energies of an artificial system obtained by holding the number of electrons fixed, doubling all nuclear charges, and halving all internuclear distances in the molecule. The approximation is shown to give a rigorous upper bound to the Hartree–Fock energy. Rationalization of schemes such as Walsh’s Rules, Woodward–Hoffmann correlation diagrams, and Hückel methods in which total energy is replaced by an orbital sum is thus suggested.
Resolved single-quantum rotational excitation in HD+He collisions: First results from a unique pulsed molecular beam apparatus
Authors: Gentry W. Ronald , Giese Clayton F.
Published: February 2003

Differential cross sections are measured for a well−resolved single−quantum rotational transition for th sampel system HD(J=O)+He→HD(J′=0,1)+He.(AIP)
Rotational effects in the F+(H2,H)FH+ reaction
Authors: Jones C. A. , Wendell K. L. , Koski W. S.
Published: February 2003

Accurate values of the exoergicity for F+(H2,H)FH+ and the deuterium analog have been determined at relative energies above 2 eV. These values imply FH+(FD+) internal energies greater than the rotationless dissociation energy which can be explained by a rotational energy barrier with partial tunneling through that barrier. Inferences are made as to the rotational and vibrational quantum numbers of the FH+(FD+) products which lead to a probable vibrational inversion. The effect of instrumental resolution is found to be important.
Ultraviolet absorption cross sections of HgI2, HgBr2, and tin (II) halide vapors
Authors: Maya Jakob
Published: February 2003

The ultraviolet absorption cross sections of HgI2, HgBr2, and tin (II) halide vapors in the region 200–400 nm have been measured. The cross sections for the tin (II) halides are higher than the mercury (II) halides. The various ground and excited state HgX, SnX radicals, and X atoms (X=I, Br, Cl) produced as a result of photodissociation in this wavelength region are discussed. From the cross sections the radiative lifetimes of the excited HgX2 and SnX2 states are calculated to be ? 10−8 sec. The optical filtering properties of the vapors at elevated temperatures are briefly discussed.
Integral equation and perturbation method for equations of state for a low temperature Lennard-Jones gas
Authors: Carley David D.
Published: February 2003

A parametric integral equation and a combination of the integral equation with perturbation theory are used to obtain theoretical thermodynamic equations of state for a low temperature Lennard-Jones 6–12 gas. Eight isotherms are studied, the temperatures extending from the critical temperature to approximately twice the critical temperature. A comparison of these results with molecular dynamics and with virial series results shows that the integral equation is to be preferred at very low densities, but that the perturbation method is better for moderate and high densities. The agreement between the integral equation and perturbation methods is quite good for the high temperatures but becomes progressively poorer for lower temperature. Combining the two methods, it is possible to obtain excellent equations of state with moderate computational effort for a simple gas over its entire temperature range, and over a wide range of densities.
Kinetics of the reaction of HO2 with NO2
Authors: Howard Carleton J.
Published: February 2003

The reaction of HO2 with NO2 has been studied using laser magnetic resonance detection of HO2 with a discharge-flow system. The proposed reaction mechanism is HO2+NO2+M k1a→HOONO2+M, and HO2+NO2 k1b→HONO+O2. Measurements were made at 300 K over the pressure range 0.5–3 torr. HO2 concentrations down to 1010 molecules/cm3 were used to eliminate side reactions. The data were analyzed on the basis of the above mechanism and the results are kla(M) = (M=He)10.0±2.5, (M=N2)20.9±5.2,(M=O2) 15.1±3.8, and (M=NO2)66±30 in the units 10−32 cm6/molecule2 s and klb<3×10−15 cm3/molecule⋅s. These results indicate that HOONO2 is the major product of Reaction (1). This conclusion is in agreement with other recent measurements.
Analytic solution of relaxation in a system with exponential transition probabilities
Authors: Penner Alvin P. , Forst Wendell
Published: February 2003

In a thermal system, the simple exponential (SE) model of transition probabilities provides a fairly simple analytical expression for the nonequilibrium rate constant (ko) for thermal dissociation of polyatomic gas. However, the SE model is poorly normalized, and because of some mathematical shortcuts it yields no relaxation times. The present work investigates two properly normalized versions of the exponential model, called Model A and Model B, and gives the analytic solution of the relaxation problem. In the case of Model A, which is the most realistic physically but difficult mathematically, the relaxation problem could be solved only for an infinite reaction threshold energy, yielding ko=0 together with a partly discrete and partly continuous spectrum of relaxation times. However, the mean first-passage time approach yields a nontrivial expression for ko that is valid under most conditions likely to be encountered in practice. Model B is physically less realistic but mathematically simpler, and yields ko essentially equivalent to that of the SE model, but also provides some indication of how the relaxation times depend on the threshold energy. It is shown that the SE model yields a reliable ko only when energy transfer is inefficient and the threshold to reaction is high.
Mean spherical approximation and optimized cluster theory for the square-well fluid
Authors: Smith William R. , Henderson Douglas , Tago Yoshio
Published: February 2003

The mean spherical approximation and the related optimized cluster theory are applied to the square-well fluid with a well width of 0.5σ, where σ is the hard-sphere diameter. The resulting equations of state and radial distribution functions are determined numerically and compared both with computer simulation results and with previously reported Percus–Yevick and hyper-netted chain theory calculations. In general, the mean spherical approximation results are more accurate than those of the optimized cluster theory. This is especially true if the energy equation is used. Both approximations are more accurate than the Percus–Yevick and hyper-netted chain approximations.
Temperature dependence of specific heat of perfluoromethylcyclohexane/carbon tetrachloride mixtures of critical composition near the critical solution temperature
Authors: Pelger M. , Klein H. , Woermann D.
Published: February 2003

Measurements of the temperature dependence of specific heat of a perfluoromethylcyclohexane/ carbon tetrachloride mixture of critical composition near the critical solution temperature Tc are reported. The experiments are carried out in an isothermal heat flow calorimeter in a temperature range of 4×10−3 K? (T-Tc) ?10.921 K. The experimental results are discussed in terms of current concepts of critical phenomena.
Molecular dynamics study of linear diatomic chain
Authors: Parliński K. , Mituś A. C. , Sikora R. , Wasiutyński T.
Published: February 2003

The molecular dynamics method is applied to a linear system of 64 diatomic molecules with periodic boundary conditions. The molecules interact via the sum of harmonic and quadrupole potentials. A pseudo phase transition from hindered to rotational diffusion is found. Results are given for energy, specific heat, equation of state, order parameter, dynamical structure factor, angular velocity correlation function, and relaxation times. At low temperature the peaks in the dynamical structure factor can be identified with translational and torsional phonons. They generally agree with the predictions of harmonic lattice dynamics. At high temperatures the existence of large quasielastic peaks indicates on the rotational diffusion of molecules. The model is tested by both the classical and quantum pseudoharmonic approximations.
Coupled equations applied to the photodissociation of linear triatomics: A test of approximate schemes for calculating the line shape and the effect of final states interactions
Authors: Atabek O. , Lefebvre R.
Published: February 2003

Coupled equations are used to obtain the line shape and the final probability distribution of linear triatomic molecules undergoing photodissociation. These calculatins provide a test for some current approximations made in the evaluation of the one-dimensional nuclear overlap integrals needed for the bound-free couplings. The linearization of the repulsive potential yiels a line shape of correct position and width, although with a somewhate reduced area. The uniform Airy approximation is superior at most energies but may fail at some energy within the line shape. This behavior can be related to a small difference in slopes of the potentials at a crossing point. A study has also been made of the half-collision formalism which relates the probability distribution for the vibrational states of the diatomic fragment to bound–free couplings and matrix elements of the transition operator on the repulsive surface. It is found that this procedure underestimates the rearrangement of probabilities resulting from final states interactions.
Electrical behavior of sulfur up to 600 kbar—metallic state
Authors: Dunn K. J. , Bundy F. P.
Published: February 2003

Using a sintered diamond tipped opposed piston apparatus the electrical resistance behavior of sulfur has been studied to pressures well over 500 kbar and to temperature of a few hundred °C. At about 300 kbar the resistance starts dropping below the cell background value of about 108 ohm and continues to drop with pressure until about 500 kbar where a steady value of about 10 ohm is reached. In this latter state the dR/dT is positive, indicating metallic character. Temperature cycling the specimen at lower pressures yields negative dR/dT, characteristic of semiconduction. The measured activation energy of semiconduction drops linearly with pressure until the metallic state is reached. The resisitivity in the metallic state is about 0.03 ohm cm. The higher temperature behavior in the metallic state was explored by pulse heating for intervals of the order of a hundred microseconds. An abrupt resistance drop occurs at about 600 °C which is probably the melting temperature of the metallic phase.
Hypersonic sound velocities in aqueous salt solutions
Authors: Chen S.-H. , Lai C. C. , Rouch J.
Published: February 2003

High frequency sound propagation has been studied for aqueous solutions of NaCl, KCl, and KBr at various concentrations and temperatures. We believe the data taken at high temperature are reported for the first time. Our results are consistent with ultrasonic and most of light scattering data whenever available but disagree with findings of Gross et al. By analyzing the various physical processes which may give rise to a sound velocity dispersion, we show that Gross et al. findings are probably due to artifacts.
Electron attachment to nitro compounds in liquid cyclohexane
Authors: Bakale George , Gregg Earle C. , McCreary Richard D.
Published: February 2003

The electron attachment rate constants of more than 50 nitro compounds (nitroaliphatic and mono- and poly-substituted nitrobenzenes) were measured in cyclohexane at 20 °C using a pulsed conductivity technique. Among the mono-substituted nitrobenzenes, a correlation between the electron attachment rate and the solute dipole moment was found. Application of the Smoluchowski–Debye equation for diffusion-controlled reactions to the electron attachment process with consideration of electron–solute dipole and induced dipole interactions permitted the calculation of attachment rate constants which agreed within 20 percent of the measured values for almost all of the mono-substituted nitrobenzene. The effects of solute structure on the electron attachment rate is also discussed.
Mechanisms of energy transfer in hydrogen fluoride systems
Authors: Wilkins Roger L.
Published: February 2003

Rate coefficients are calculated for the energy-transfer processes that ocuur when HF(v1,J1) molecules collide with HF(v2, J2) molecules. Three-dimensional classical trajectories of the collision dynamics of these energy-transfer processes were calculated by means of a potential energy surface, which consists of a London–Eyring–Polanyi–Sato (LEPS) potential function for the short-range interactions and a partial-point-charge, dipole–dipole function for long-range interactions. This energy surface was used to predict an equilibrium geometry of the HF dimer. From the trajectory calculations it was predicted that the v→v energy-transfer processes occur by means of Δv=±1 transitions and that the rate coefficients for the processes HF(v)+HF(v=0) →HF(v−1)+HF(v=1) decrease with increasing vibrational quantum number v. A calculation of the v→v rate for the reaction HF(v=1)+HF(v=1) →HF(v=0)+HF(v=2) indicates a value of 1.2×1013 cm3 mol−1 s−1 at 300 K. This process corresponds to near-resonant vibration-to-vibration (v→v) intermolecular energy transfer. The major contribution toward the rate coefficients for the energy transfer mechanisms comes from the rotating HF molecules. The vibrationally excited HF rotor takes the energy mismatch ΔE, corresponding to rotationless HF molecules, away by means of a vibration-to rotation (v→R) energy-transfer process. This process corresponds to a nonresonant v→R intramolecular energy transfer. Multiquantum v→R processes are predicted. At low v it is predicted that one in three HF–HF collisions produces v→R energy transfer. For many of the important v→R energy-transfer processes the energy defect is less than 200 cm−1. The trajectory calculations indicate that the number of v→R open channels increases with increasing v. The multiquantum v→R transitions provide more ways to distribute the vibration energy of the vibrationally excited HF molecules into rotational energy, i.e., into very high rotational quantum states. The high rotational quantum states are quickly relaxed by R→v processes and by fast v→R processes in which even higher rotational quantum states are produced. The high rotational quantum states are relaxed slowly by R→R, T processes.
Reactivity bands in atom–molecule collisions. III. The coplanar (H, H2) reaction
Authors: Tan K. G. , Laidler Keith J. , Wright James S.
Published: February 2003

The coplanar collision of H+H2 is studied by quasiclassical methods for translational energies of 0–2 eV. By using systematic selection of initial conditions, reactivity bands are obtained in 2D which are analogous to those seen previously in 1D. Reaction time, product scattering angle, and product internal energy show extrema at band edges. By use of continuity, reactivity maps and product attribute maps are obtained, which show the possible outcome of any given trajectory at selected values of the internal coordinates. Opacity functions and excitation functions are given and compared to those obtained from Monte Carlo calculations on the same system. The origin of time peaks is examined in terms of the internal modes of the H3 complex, including the asymmetric stretch. The orientation effect of the H3 surface is discussed and used to account for trends in threshold and antithreshold values, and in the increased reactivity observed for nonlinear configurations. Coplanar reaction mechanisms are analyzed and compared to 3D results.