bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrocatalytic Oxidation of Sulfite on a Cobalt Pentacyanonitrosylferrate Film Modified Glassy Carbon Electrode
Authors: Pournaghi‐Azar M. H. , Sabzi R. E.
Published: March 2004

The electrocatalytic oxidation of sulfite has been studied on the cobalt pentacyanonitrosylferrate modified glassy carbon electrode (CoPCNF). The CoPCNF films on the glassy carbon electrodes show an excellent electrocatalytic activity toward the oxidation of sulfite in 0.5 M KNO3. The kinetics of the catalytic reaction was investigated by using cyclic voltammetry, rotating disk electrode (RDE) voltammetry and chronoamperometry. The average value of the rate constant, K, for the catalytic reaction and the diffusion coefficient, D, were evaluated by different approaches for sulfite and found to be 2.9×102 M−1s−1 and 4.6×10−6 cm2s−1, respectively. At a fixed potential under hydrodynamic conditions (stirred solutions), the oxidation current is proportional to the sulfite concentration and the calibration plot was linear over the concentration range 5×10−6–1×10−4 M. The detection limit of the method is 3×10−6 M., low enough for the trace sulfite determination.
Determination of an Ethylene Bisdithiocarbamate Based Pesticide (Nabam) by Cobalt Phthalocyanine Modified Carbon Ink Electrode
Authors: Lin Meng Shan , Wang Jun Sheng
Published: March 2004

A phthalocyanine based sensor, for anodic detection of sodium ethylene bisdithiocarbamate (Nabam) by coating a mixture of cobalt phthalocyanine (CoPC) modified carbon ink on the surface of a glassy carbon electrode, has been described. The modified ink was prepared by mixing three percent of cobalt phthalocyanine into carbon ink and then diluting the mixture with cyclohexanone in w/w ratio of 1/9. A suitable portion (or 1 μL) of ink mixture was then dip‐coated on a rotating disk glassy carbon electrode. The modified ink electrode was air‐dried for 15 mins before use. In comparison to the bare ink electrode on which the oxidation of Nabam takes place at 300 mV (vs. 3 M Ag/AgCl), the oxidation potential (−125 mV) of Nabam at the CoPC modified ink decreases significantly. A typical calibration plot of Nabam proportionally increases over the concentration range of 2.5 to 36 μM (R=0.9990). The detection limit is estimated about 28.8 nM (S/N=3) and its response time (between 10% to 90% of steady‐state response) is about 5.3 s at the injection of 5 μM Nabam. The sensitivity requirement of JMPR meeting (Joint FAO/WHO Meeting on Pesticide Residues) for ethylene bisdithiocarbamates (EBDCs) is achieved by this proposed scheme.
Electrochemical Detection of As(III) via Iodine Electrogenerated at Platinum, Gold, Diamond or Carbon‐Based Electrodes
Authors: Hignett Geraldine , Wadhawan Jay D. , Lawrence Nathan S. , Hung Dang Q. , Prado César , Marken Frank , Compton Richard G.
Published: March 2004

The reaction of iodine, electrogenerated from iodide, is used for the detection of As(III) via electrocatalytic reaction in the diffusion layer of a boron‐doped diamond electrode. The merits of this electrode material for this purpose (over platinum, gold or glassy carbon) are demonstrated and the kinetics of the reaction between I2 and As(III) in acid reported.
Dopamine and Glucose Sensors Based on Glassy Carbon Electrodes Modified with Melanic Polymers
Authors: González Rosa , Sánchez Alberto , Chicharro Manuel , Rubianes María D. , Rivas Gustavo A.
Published: March 2004

This work deals with the study of polymers electrogenerated from different catechols at glassy carbon electrodes and the analytical applications of the resulting modified electrodes for dopamine quantification and glucose biosensing. The electropolymerization was performed from a 3.0×10−3 M catechol solution (catechol, dopamine, norepinephrine, epinephrine or L‐dopa in a 0.050 M phosphate buffer pH 7.40) by applying 1.00 V for 60 min. The properties of the polymers are very dependent on the nature of the catechol, L‐dopa being the best. Glassy carbon electrodes modified with melanic polymers electrogenerated from L‐dopa and norepinephrine were found to be suitable for dopamine determinations in flow systems, although the behavior was highly dependent on the nature of the monomer. Detection limits of 5.0 nM dopamine and interferences of 9.0 and 2.6% for 5.0×10−4 M ascorbic acid and 5.0×10−5 M dopac, respectively, were obtained at the glassy carbon electrode modified with a melanin‐type polymer generated from L‐dopa (using 1.0×10−3 M AA in the measurement solution). The advantages of using a melanin‐type polymer generated from dopamine to improve the selectivity of glucose biosensors based on carbon paste electrodes containing Pt and glucose oxidase (GOx) are also discussed. The resulting bioelectrodes combines the high sensitivity of metallized electrodes with the selectivity given by the polymeric layer. They exhibit excellent performance for glucose with a rapid response (around 10 seconds per sample), a wide linear range (up to 2.5×10−2 M glucose), low detection limits (143 μM) and a highly reproducible response (R.S.D of 4.9%). The bioelectrodes are highly stable and almost free from the interference of large excess of easily oxidizable compounds found in biological fluids, such as ascorbic acid (AA), uric acid (UA) and acetaminophen.
Organic Redox Probes for the Key Oxidation States in Mixed Valence Ruthenium Oxide/Cyanometallate (Ruthenium Prussian Blue Analogue) Catalysts
Authors: Kumar Annamalai Senthil , Zen Jyh‐Myng
Published: March 2004

The electrochemical redox behavior of the polynuclear mixed valence ruthenium oxide cyanometallate complexes (mvRuOxMCN, M=Fe, Cr, Ni, Cu, Ru and Pt) have been systematically studied in this report by using three redox sensitive organic probes of glucose, ethanol and formaldehyde. The results were interpreted by the well‐established ruthenium oxide and Prussian blue chemistry. The mvRuOxMCN, under the category of Ru‐based Prussian blue analogue, was found to possess superior electrocatalytic activity than either ruthenium oxide or Prussian blue in acidic mediums. The electrogenerated oxy/hydroxy‐RuVII state (at +1.1 V vs. Ag/AgCl) was unusually stabilized in the mvRuOxMCN matrix without any disproportion reaction in acidic environments. In contrast to those of earlier studies, possible structure in terms of the RuIII/IINCMand RuIII/IIORuVII/VIsites was proposed here. Enzyme‐less analytical detection of glucose in acidic conditions was first time demonstrated with sensitivity comparable to that of ruthenium oxide‐based electrodes in alkaline solutions.
Electrochemical Properties of Lanthanum Hexacyanoferrate Particles Immobilized onto Electrode Surface by Au‐Codeposition Method
Authors: Eftekhari Ali
Published: March 2004

Lanthanum hexacyanoferrate (LaHCF) was immobilized onto a substrate surface as an electroactive material by Au‐codeposition method. The LaHCF particles were attached to the electrode surface as the result of occlusion within the gold film deposited. This deposition method was first introduced for the preparation of hexacyanoferrate‐based modified electrodes. It was demonstrated that this deposition method provides a higher stability of the electroactive film in comparison with available methods for the mechanical attachment of electroactive films. On the other hand, electrochemical properties of the LaHCF film modified electrode were studied for the first time. The results showed that LaHCF film has excellent electrochemical activity as well as other analogues of Prussian blue. The modified electrode was successfully used as an electrocatalyst for the oxidation of ascorbic acid.
Characterization of Carbon Film Electrodes for Electroanalysis by Electrochemical Impedance
Authors: Filipe Olga M. S. , Brett Christopher M. A.
Published: March 2004

The interfacial behavior of electrodes fabricated from carbon film resistors of 2 and 20 Ω in supporting electrolyte solutions of varying pH used in electroanalytical experiments has been characterized by electrochemical impedance spectroscopy with complementary cyclic voltammetric experiments. Equivalent circuits are proposed to fit the experimental data and the influence of electrode pretreatment has also been investigated.
Electroactive Ceramic Carbon Electrode Modified with Hydrophobic Polar Solvent
Authors: Shul Galyna , Saczek‐Maj Monika , Opallo Marcin
Published: March 2004

Ceramic carbon electrode modified with redox probe solution in hydrophobic polar solvent was prepared and studied. The electrode consisting of graphite powder, homogeneously dispersed in hydrophobic silicate matrix, was prepared from the mixture of methyltrimethoxysilane based sol and graphite powder by sol‐gel method. It was immersed in t‐butyloferrocene solution in nitrobenzene. The electrode properties were investigated by cyclic voltammetry and chronoamperometry in KNO3 solution of different concentration. In most cases linear polarization of the electrode towards positive potentials results in peak shaped voltammogram originating from electrooxidation of t‐butyloferrocene. Its shape changes with time, but after 5–7 scans stable curve is obtained. In all conditions the anodic to cathodic charge ratio is larger than unity. The peak current is proportional to the concentration of the redox probe in organic phase and salt in aqueous phase, whereas the midpeak potential is almost not affected by these factors. It has been concluded, that the electrooxidation of redox probe within hydrophobic silicate matrix is followed by two simultaneous processes: t‐butyloferrocenium cation transfer to the aqueous phase and anion transfer from aqueous phase. Their relative contribution depends on the ratio of concentration of the redox probe in organic phase to concentration of salt in aqueous phase.
What factors influence failure to engage in a supervised self‐help programme for bulimia nervosa and binge eating disorder?
Authors: Bell Lorraine , Newns Kathryn
Published: March 2004

The study investigated factors influencing failure to engage among a group of bulimic and binge eating disordered clients referred to a supervised self‐help programme. A total of 125 patients referred to a supervised self‐help programme for people with bulimia and binge eating disorder were grouped into those who were seen in treatment (n = 85), and those who failed to engage i.e. did not attend their initial appointment (n = 40). Diagnosis, age, gender and waiting times of the two groups were compared. Diagnosis, age and gender were not significantly different between the two groups. The only significant factor measured was the length of time that they had waited between being referred to the service and their appointment date. Clients who waited less than 4 weeks were 2.4 times more likely to attend their appointment. For every week that lapsed between referral and appointment date, the odds of attending were reduced by 15% (p = 0.002). The results are discussed in light of the importance of maximizing engagement in treatment. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Processing of five types of ‘threat’ information in anorexic and bulimic women
Authors: Quinton Stephanie
Published: March 2004

This study investigated further the ‘escape’ hypothesis of bulimia and compared the processing of ‘threat’ information in control, anorexic and bulimic women. Using a novel information‐processing task, five types of non‐eating ‘threat’ (autonomy, sociotropy, discomfort anxiety, ego threat from others and ego threat from self) were addressed. The women did not differ in response time taken to identify ‘threat’ information, although there was support for the ‘escape’ hypothesis of bulimia. Specific non‐eating ‘threat’ information appeared relevant to both anorexia and bulimia nervosa, suggesting the potential value of addressing general threat schemata in clinical practice. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Childhood onset anorexia nervosa: the experience of parents
Authors: Cottee‐Lane Danielle , Pistrang Nancy , Bryant‐Waugh Rachel
Published: March 2004

This qualitative study examined the experience of parents who had a child with early onset anorexia nervosa. Semi‐structured interviews were conducted with 11 parents (seven mothers and four fathers). Qualitative data analysis yielded eight core themes structured around three broad domains: understanding the eating disorder, the impact of the eating disorder, and managing the eating disorder and its impact. The themes revealed that the experience of having a child with anorexia nervosa is extremely demanding and personally challenging for parents. Despite this, parents remained determined to help their child in the face of this debilitating condition. The implications for the delivery of services for children and adolescents with eating disorders and their families are discussed. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Eating attitudes among college students in Malaysia: an ethnic and gender comparison
Authors: Edman Jeanne L. , Yates Alayne
Published: March 2004

The purpose of this study was to examine whether there are gender and ethnic differences in eating attitudes among ethnic Malay and ethnic Chinese college students in Malaysia, and whether eating attitudes are related to BMI and measures of self‐dissatisfaction and separation anxiety. The Eating Attitudes Test‐26 (EAT‐26), the Separation Anxiety Symptom Inventory, and a self‐dissatisfaction scale were administered to 187 Malay and 80 Chinese students. There were no sex differences in disordered eating attitudes for either ethnic group, however, Malay students scored higher on the EAT‐26 than the Chinese students. Separation anxiety was related to EAT‐26 scores among female participants but not among males. Levels of self‐dissatisfaction were associated with EAT‐26 scores among Malay males and Chinese females. Contrary to findings commonly found among Westerners, there were no gender differences in disordered eating attitudes among college students in Malaysia. However, there were gender differences in what factors were associated with disordered eating attitudes. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Pressure weighted upwinding for flow induced force predictions: application to iced surfaces
Authors: Naterer G. F.
Published: March 2004

This paper addresses two main topics, namely the development of a pressure‐weighted upwinding method and its application to flow induced forces on iced cylinders. Although the near‐wall convective upwinding exhibits special applicability to iced surfaces, its capabilities extend more generally to other applications. By fully linking pressure and velocity at a sub‐element level near the wall, a higher order accuracy can be obtained. Also, a non‐physical de‐coupling between pressure and velocity can be prevented. The method is developed under the context of a control‐volume‐based finite element method for 2‐D, incompressible flows. Drag and lift coefficients are predicted, based on the pressure weighted upwinding near the wall. The numerical predictions are successfully compared against experimental data, including flow induced forces on iced cables. Copyright © 2004 John Wiley & Sons, Ltd.
Interfacial dynamics‐based modelling of turbulent cavitating flows, Part‐2: Time‐dependent computations
Authors: Senocak Inanc , Shyy Wei
Published: March 2004

The interfacial dynamics‐based cavitation model, developed in Part‐1, is further employed for unsteady flow computations. The pressure‐based operator‐splitting algorithm (PISO) is extended to handle the time‐dependent cavitating flows with particular focus on the coupling of the cavitation and turbulence models, and the large density ratio associated with cavitation. Furthermore, the compressibility effect is important for unsteady cavitating flows because in a water–vapour mixture, depending on the composition, the speed of sound inside the cavity can vary by an order of magnitude. The implications of the issue of the speed of the sound are assessed with alternative modelling approaches. Depending on the geometric confinement of the nozzle, compressibility model and cavitation numbers, either auto‐oscillation or quasi‐steady behaviour is observed. The adverse pressure gradient in the closure region is stronger at the maximum cavity size. One can also observe that the mass transfer process contributes to the cavitation dynamics. Compared to the steady flow computations, the velocity and vapour volume fraction distributions within the cavity are noticeably improved with time‐dependent computations. Copyright © 2004 John Wiley & Sons, Ltd.
Functional analysis of the periphery effect in human building related areas
Authors: Levy Ifat , Hasson Uri , Harel Michal , Malach Rafael
Published: March 2004

Several studies have shown that a region in the anterior collateral sulcus (CoS) and a region in the vicinity of the transverse occipital sulcus (TOS) are preferentially activated by images of buildings and scenes. We have found recently that these regions show a strong activation bias to stimuli located in the peripheral visual field. We explore in detail the source of this “periphery” effect. Our results show that the periphery effect can be generated by a large single object occupying the peripheral visual field as well as by multiple small peripheral objects. We also investigated whether the periphery effect was related to the annular shape used in conventional mapping of the visual field periphery and found that the mere presence of a stimulus in the visual field periphery, regardless of object shape, is sufficient to enhance activation. We also found that a small bias toward the peripheral visual field was shown even when the stimulated areas in the central and peripheral parts of the visual field are equated. Finally, our results demonstrate that the periphery effect shows object selectivity that can be obtained even with face images, which are the non‐optimal stimulus for this region. In summary, our study shows that the building‐related CoS and TOS manifest a true but graded retinotopic bias toward the peripheral visual field. Hum. Brain Mapp. 22:17–28, 2004. © 2004 Wiley‐Liss, Inc.
Comparison of simultaneously recorded [H215O]‐PET and LORETA during cognitive and pharmacological activation
Authors: Gamma Alex , Lehmann Dietrich , Frei Edi , Iwata Kazuki , Pascual‐Marqui Roberto D. , Vollenweider Franz X.
Published: March 2004

The complementary strengths and weaknesses of established functional brain imaging methods (high spatial, low temporal resolution) and EEG‐based techniques (low spatial, high temporal resolution) make their combined use a promising avenue for studying brain processes at a more fine‐grained level. However, this strategy requires a better understanding of the relationship between hemodynamic/metabolic and neuroelectric measures of brain activity. We investigated possible correspondences between cerebral blood flow (CBF) as measured by [H2O]‐PET and intracerebral electric activity computed by Low Resolution Brain Electromagnetic Tomography (LORETA) from scalp‐recorded multichannel EEG in healthy human subjects during cognitive and pharmacological stimulation. The two imaging modalities were compared by descriptive, correlational, and variance analyses, the latter carried out using statistical parametric mapping (SPM99). Descriptive visual comparison showed a partial overlap between the sets of active brain regions detected by the two modalities. A number of exclusively positive correlations of neuroelectric activity with regional CBF were found across the whole EEG frequency range, including slow wave activity, the latter finding being in contrast to most previous studies conducted in patients. Analysis of variance revealed an extensive lack of statistically significant correspondences between brain activity changes as measured by PET vs. EEG‐LORETA. In general, correspondences, to the extent they were found, were dependent on experimental condition, brain region, and EEG frequency. Hum. Brain Mapping 22:85–98, 2004. © 2004 Wiley‐Liss, Inc.
Simultaneous event‐related potential and near‐infrared spectroscopic studies of semantic processing
Authors: Horovitz Silvina G. , Gore John C.
Published: March 2004

Near‐infrared optical topography (NIROT) signals and event‐related potentials (ERPs) were measured simultaneously during a semantic processing task to evaluate the ability of these techniques to detect hemodynamic and electrophysiologic responses generated by semantic anomalies and to compare these results to earlier independent functional magnetic resonance imaging (fMRI) and ERP measurements. Candidate brain regions were first identified from activations detected by NIROT during a simple block‐design task (in this case reading sentences vs. passive viewing), and defined regions (corresponding to Broca's and Wernicke's areas) were used for guiding the localization of optodes and electrodes for recording during tasks involving semantic anomalies. In five of six subjects, ERP measurements showed the characteristic N400 wave, whereas event‐related NIROT showed results that agreed with previous fMRI studies. There were transient hemodynamic signals recorded in specific optodes that corresponded to activation in Broca's area, but slightly anterior to the region activated during the simple reading task, and in Wernicke's area, but slightly inferior to that for the simple reading task. A between‐subject correlation of the ERP and NIRS data was also employed to identify areas of activation. The highest correlations were obtained in Broca's area, centered more anterior than for the reading task and in Wernicke's area, slightly inferior to that for the reading task. This study confirms that event‐related studies are feasible using NIROT and produce results similar to those obtained with fMRI. Even though the spatial resolution is lower in NIROT than in fMRI, small differences in the locations of activation centers could be detected with NIROT. This, together with the feasibility of simultaneous ERP recording, makes NIROT attractive as a new approach to studying language function in healthy subjects as well as in those with functional abnormalities. Hum. Brain Mapping 22:112–117, 2004. © 2004 Wiley‐Liss, Inc.
Neural correlates of syntactic transformations
Authors: Wartenburger Isabell , Heekeren Hauke R. , Burchert Frank , Heinemann Steffi , De Bleser Ria , Villringer Arno
Published: March 2004

Many agrammatic aphasics have a specific syntactic comprehension deficit involving processing syntactic transformations. It has been proposed that this deficit is due to a dysfunction of Broca's area, an area that is thought to be critical for comprehension of complex transformed sentences. The goal of this study was to investigate the role of Broca's area in processing canonical and non‐canonical sentences in healthy subjects. The sentences were presented auditorily and were controlled for task difficulty. Subjects were asked to judge the grammaticality of the sentences while their brain activity was monitored using event‐related functional magnetic resonance imaging. Processing both kinds of sentences resulted in activation of language‐related brain regions. Comparison of non‐canonical and canonical sentences showed greater activation in bilateral temporal regions; a greater activation of Broca's area in processing antecedent‐gap relations was not found. Moreover, the posterior part of Broca's area was conjointly activated by both sentence conditions. Broca's area is thus involved in general syntactic processing as required by grammaticality judgments and does not seem to have a specific role in processing syntactic transformations. Hum. Brain Mapp. 22:74–83, 2004. © 2004 Wiley‐Liss, Inc.
EPR‐investigations of radicals derived from diethyl iodomethylphosphonate in solid and liquid state
Authors: Białas Tomasz , Szadowiak Aldona , Bałczewski Piotr
Published: March 2004

A selective homolysis of the CI bond in diethyl iodomethylphosphonate to give the diethoxyphosphorylmethyl radical (EtO)2P(O)CH2· was observed in EPR spectra upon γ‐irradiation and UV–vis photolysis. Analysis of stability of this radical was also investigated to show disappearance of EPR signals above 170–190 K. An attempt to observe this radical during the reaction with AIBN as an initiator failed. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:127–130, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10225
Calix[4]arene phosphonates ‐ recognition of amino alcohols in water
Authors: Witt Dariusz , Dziemidowicz Joanna , Rachon Janusz
Published: March 2004

The water‐soluble calix[4]arenes based cavitands were obtained in good yield by introduction of phosphonic acids groups at the upper rim; we describe the design, synthesis, and formation of the complexes with ephedrine, norephedrine, and noradrenaline hydrochloride in the phosphate buffer at pD 7.3. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:155–161, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10229
The semiempirical study on the addition of the chiral ammonium hypophosphite to an aldehyde
Authors: Lewkowski Jarosław
Published: March 2004

The PM3 and AM1 semiempirical computations were performed in order to explain the stereochemistry of the addition of the chiral α‐methylbenzylammonium hypophosphite to an aldehyde, which is stereoselective to 100%. Both mechanisms: one considering the intermediate formation of α‐hydroxy phosphonous acids followed by the nucleophilic substitution with a chiral amine and the second considering the formation of a Schiff base followed by the addition of hypophosphorous acid to an azomethine bond were taken. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:162–168, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10230
Iodochlorination of silyl‐ and germylphenylacetylenes
Authors: Selina Anastasia A. , Zhachkina Anna E. , Karlov Sergey S. , Churakov Andrei V. , Zaitseva Galina S.
Published: March 2004

Reactions of Si‐ and Ge‐substituted alkynes with KICl2 were investigated. (1‐Germatranyl)‐phenylacetylenes and (triphenylsilyl)phenylacetylene gave Z‐iodochloroalkenes with chlorine and phenyl groups attached to the same carbon atom. Adduct structures were confirmed by X‐ray diffraction studies. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:169–174, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20001
When does quality‐adjusting life‐years matter in cost‐effectiveness analysis?
Authors: Chapman Richard H. , Berger Marc , Weinstein Milton C. , Weeks Jane C. , Goldie Sue , Neumann Peter J.
Published: March 2004

Purpose: This paper investigates the impact of quality‐of‐life adjustment on cost‐effectiveness analyses, by comparing ratios from published studies that have reported both incremental costs per (unadjusted) life‐year and per quality‐adjusted life‐year for the same intervention.

Methods: A systematic literature search identified 228 original cost–utility analyses published prior to 1998. Sixty‐three of these analyses (173 ratio pairs) reported both cost/LY and cost/QALY ratios for the same intervention, from which we calculated medians and means, the difference between ratios (cost/LY minus cost/QALY) and between reciprocals of the ratios, and cost/LY as a percentage of the corresponding cost/QALY ratio. We also compared the ratios using rank‐order correlation, and assessed the frequency with which quality‐adjustment resulted in a ratio crossing the widely used cost‐effectiveness thresholds of $20000, $50000, and $100000/QALY or LY.

Results: The mean ratios were $69100/LY and $103100/QALY, with corresponding medians of $24600/LY and $20400/QALY. The mean difference between ratios was approximately −$34300 (median difference: $1300), with 60% of ratio pairs differing by $10000/year or less. Mean difference between reciprocals was 59 (QA)LYs per million dollars (median: 2.1). The Spearman rank‐order correlation between ratio types was 0.86 (p<0.001). Quality‐adjustment led to a ratio moving either above or below $50000/LY (or QALY) in 8% of ratio pairs, and across $100000 in 6% of cases.

Conclusions: In a sizable fraction of cost–utility analyses, quality adjusting did not substantially alter the estimated cost‐effectiveness of an intervention, suggesting that sensitivity analyses using ad hoc adjustments or ‘off‐the‐shelf’ utility weights may be sufficient for many analyses. The collection of preference weight data should be subjected to the same scrutiny as other data inputs to cost‐effectiveness analyses, and should only be under‐taken if the value of this information is likely to be greater than the cost of obtaining it. Copyright © 2004 John Wiley & Sons, Ltd.
Asymmetric Syntheses of 2‐(1‐Aminoethyl)phenols
Authors: Kündig E. Peter , Botuha Candice , Lemercier Gilles , Romanens Patrick , Saudan Lionel , Thibault Sylvie
Published: March 2004

Three different routes were probed for the synthesis of enantiomerically enriched 2‐(1‐aminoethyl)phenols and their methyl ethers. The first route centers on diastereoselective nucleophile addition to chiral imines. The second route has as key steps the enantioselective reduction of a ketone followed by nucleophilic substitution, and the third route involves a diastereoselective imine reduction. The efficiency of the approach depends on the substrate substitution pattern. All three methods work well for the parent compound 2‐(1‐aminoethyl)phenol (1) but the third route is the most efficient, providing the compound with >96% enantiomer excess in three steps with an overall yield of 71%. Conversely, for the ortho‐methyl analogue 2, the first method is best. For the t‐Bu‐substituted analogue 3, only moderate enantiomeric enrichment was achieved.
Bioactive Chemical Constituents of Cladiella Species
Authors: Ata Athar , Ackerman Joe , Bayoud Abdelhamid , Radhika Parvataneni
Published: March 2004

From the methanolic extract of Cladiella sp., collected from the Andaman Island, India, a new sesquiterpene, cladidiol (2), and three known diterpenes, cladiellaperoxide (3), (6E)‐2α,9α‐epoxyeunicella‐6,11(12)‐dien‐3β‐ol (4), and polyanthellin A (5) were isolated. The structures of these compounds were established by extensive spectroscopic studies. Compound 2 exhibited modest acetylcholinesterase‐inhibition activity, and compounds 3–5 showed antibacterial activities against Streptococcus pyogenes, Escherichia coli, and Pseudomonas aeruginosa.
Catalytic Asymmetric Chlorination of β‐Keto Esters with Hypervalent Iodine Compounds
Authors: Ibrahim Hasim , Kleinbeck Florian , Togni Antonio
Published: March 2004

(Dichloroiodo)toluene (=dichloro(4‐methylphenyl)iodine; 2) was found to be a suitable chlorinating agent in the catalytic asymmetric chlorination of β‐keto esters 3 catalyzed by the [Ti(TADDOLato)] complex 1 (=bis(acetonitrile)dichloro[(4R,5R)‐2,2‐dimethyl‐α,α,α′,α′‐tetra(naphthalen‐1‐yl)‐1,3‐dioxolane‐4,5‐dimethanolato(2−)‐κO,κO′]titanium), whereby α‐chlorinated products were obtained in moderate to good yields and enantioselectivities of up to 71% (Scheme 2, Table 2). The enantioselectivity of the reaction shows a remarkable temperature dependence, the maximum selectivity being obtained at ca. 50°.
Two New Triterpene and a New Nortriterpene Glycosides from Phlomis viscosa
Authors: Çalış İhsan , Kırmızıbekmez Hasan , Taşdemir Deniz , Rüedi Peter
Published: March 2004

The isolation and structure elucidation of two new oleanane‐type triterpene glycosides, 29‐(β‐D‐glucopyranosyloxy)‐2α,3β,23‐trihydroxyolean‐12‐en‐28‐oic acid (=(2α,3β,4α,29α)‐29‐(β‐D‐glucopyranosyloxy)‐2,3,23‐trihydroxyolean‐12‐en‐28‐oic acid; 1) and its C(20)‐epimer, 30‐(β‐D‐glucopyranosyloxy)‐2α,3β,23‐trihydroxyolean‐12‐en‐28‐oic acid (=(2α,3β,4α,29β)‐29‐β‐D‐glucopyranosyloxy)‐2,3,23‐trihydroxyolean‐12‐en‐28‐oic acid; 2), and a novel nortriterpene glycoside, (17S)‐2α,18β,23‐trihydroxy‐3,19‐dioxo‐19(18→17)‐ abeo‐28‐norolean‐12‐en‐25‐oic acid β‐D‐glucopyranosyl ester (=(1R,2S,4aS,4bR,6aR,7R,9R,10aS,10bS)‐3,4,4a,4b,5,6,6a,7,8,9,10,10a,10b,11‐tetradecahydro‐1‐hydroxy‐7‐(hydroxymethyl)‐3′,4′,4a,4b,7‐pentamethyl‐2′,8‐ dioxospiro[chrysene‐2(1H),1′‐cyclopentane]‐10a‐carboxylic acid β‐D‐glucopyranosyl ester; 3) from Phlomis viscosa (Lamiaceae) are reported. The structures of the compounds were asigned by means of spectroscopic (IR, 1D‐ and 2D‐NMR, and LC‐ESI‐MS) and chemical (acetylation) methods.
Synthesis of 13C‐Labeled Pyrazinone Thrombin Inhibitors and Elucidation of Metabolic Activation Pathways
Authors: Ho Jonathan Z. , Braun Matthew P. , Subramanian Raju , Gao Ying‐Duo , Dean Dennis C. , Melillo David G.
Published: March 2004

In support of a research program aimed at discovering orally bioavailable thrombin inhibitors, 13C‐ labeled 3‐aminopyrazinone acetamide thrombin inhibitors have been prepared to aid in the structural elucidation of key metabolites during preclinical and clinical studies. A method for the 13C‐labeling of pyrazinones utilizing 13C‐glycine as a building block has been developed in a good overall yield. Two targets with labels at different positions have been prepared. NMR Studies not only led to the structure of a major metabolite, but also revealed a likely metabolic pathway, which will provide structural guidance for the design and synthesis of future thrombin inhibitors as well as other pyrazinone‐containing compounds.
Improved Access to Imidazole‐phosphonic Acids: Synthesis of D‐manno‐Tetrahydroimidazopyridine‐2‐phosphonates
Authors: Terinek Miroslav , Vasella Andrea
Published: March 2004

The D‐manno‐tetrahydroimidazopyridine‐2‐phosphonate 11 was prepared via a high‐yielding Pd(PPh3)4‐catalysed diphenylphosphonylation of the manno‐iodoimidazole 12, followed by transesterification to the diethyl phosphonate 14 and dealkylation, providing 11 in eight steps from the thionolactam 1 and in an overall yield of 15%. Alternatively, a more highly convergent synthesis based on the HgCl2/Et3N‐promoted condensation of the thionolactam 1 with the α‐aminophosphonate 24 in THF led to 11 in four steps and in the same overall yield. In the presence of HgCl2/Et3N, the thionolactam 1 reacted at 80° with 2‐methoxyethanol to provide 66% of a 64 : 36 mixture of the gluco‐ and manno‐iminoethers 29/30. Performing the reaction at 22° yielded preferentially the gluco‐isomer 29 (86%, 84 : 16).
Inhibitory Effects by Ascorbic Acid on the Oscillations of the BriggsRauscher Reaction
Authors: Furrow Stanley D. , Höner Kerstin , Cervellati Rinaldo
Published: March 2004

The BriggsRauscher oscillating reaction (in batch mode) has been shown to be sensitive to various antioxidants, some of which cause cessation of oscillations for a period of time, before a restart occurs. The length of time before oscillations restart is related to the type of antioxidant and its concentration. Procedures have been devised to apply this method as a tool for measuring antioxidant activities of pure compounds and of extracts of natural sources. The antioxidant activity in the BriggsRauscher system has been generally related to the reaction of an antioxidants with hydroperoxy radicals (HOO.) present in the oscillating system. Thereby, at low concentration (<2×10−4 M), ascorbic acid is known to have a little effect on the reaction. However, there is a concentration range, where a nearly linear relation is observed between ascorbic acid concentration and inhibition time. We were able to model this type of inhibition by the reducing power of ascorbic acid without invoking a reaction with HOO..
Synthesis of [2′‐2H1]‐Ribonucleosides
Authors: Földesi András , Kundu Mrinal K. , Dinya Zoltán , Chattopadhyaya Jyoti
Published: March 2004

New syntheses of C(2′)‐deuterated ribonucleosides have been accomplished starting either from 3,5‐di‐O‐benzyl‐1‐O‐methyl‐α,β‐D‐ribofuranose (1b) or 2,3‐O‐isopropylidene‐D‐ribose (14), with >97 atom‐% D incorporation in both cases. The former is suited to the demands of multiple‐site deuteration or uniform 13C/multiple 2H double labeling of the ribofuranose moiety, whereas the latter is particularly appropriate for single‐site 2H labeling for mechanistic studies of enzyme reactions.
Chemical Constituents from the Pericarp of Trewia nudiflora
Authors: Du Zhi‐Zhi , He Hong‐Ping , Wu Bin , Shen Yue‐Mao , Hao Xiao‐Jiang
Published: March 2004

Three new ent‐atisane diterpenes, i.e., 17‐hydroxy‐ent‐atisan‐19‐oic acid (1), 17‐hydroxy‐ent‐atisan‐19‐oic acid methyl ester (2), and 16α,17‐dihydroxy‐ent‐atisan‐19‐al (3), together with five known phenolic compounds, i.e., gallic acid, ethyl gallate, protocatechuic acid, 3,4,4′‐tri‐O‐methylellagic acid, and α‐tocopherol, and two other known compounds, i.e., trans‐cinnamic acid and taraxerone, were isolated from the pericarp of Trewia nudiflora collected in Xishuangbanna, Yunnan Province, China. Their structures were elucidated by spectroscopic analysis including 1D‐ and 2D‐NMR. Trace amounts of maytansinoids were isolated by antifungal‐activity‐guided fractionation and determined by LC‐ESI‐MS analysis; they were prominent antifungal constituents in the pericarp of Trewia nudiflora.
Throughflow variability during snowmelt in a forested mountain catchment, coastal British Columbia, Canada
Authors: Kim Hyeon Jeong , Sidle Roy C. , Moore R. D. , Hudson R.
Published: March 2004

This study documented the spatial and temporal variability of outflow from a forested hillslope segment during snowmelt at a small mountain catchment in south coastal British Columbia, Canada. A pit 5 m wide was established just upslope from the stream channel. Outflow from the organic horizon was intercepted and measured by a single trough, and outflow from the mineral horizons was measured separately for three adjacent sections. Throughflow exhibited non‐steady‐state behaviour involving shifting allocations of flow amongst different sections of the outflow pit, as well as threshold effects and hysteresis in the relationship between pit outflow and water table elevation. Most of the pit outflow originated from the mineral horizons, indicating that throughflow was the dominant pathway by which water was delivered to the stream channel. Direct precipitation and snowmelt onto near‐stream saturated areas can account for less than 20% of the total outflow from the hillslope segment. Throughflow from the mineral sections consistently peaked either at the same time as or earlier than stream flow from the 150‐ha catchment during diurnal snowmelt cycles, indicating that throughflow appears to respond rapidly enough to contribute to snowmelt‐induced peak stream flow. Pit outflow cannot be extrapolated reliably to the catchment scale on the basis of simple length‐ or area‐based ratios. Copyright © 2004 John Wiley & Sons, Ltd.
Geostatistical analysis and conditional simulation for estimating the spatial variability of hydraulic conductivity in the Choushui River alluvial fan, Taiwan
Authors: Jang Cheng‐Shin , Liu Chen‐Wuing
Published: March 2004

This work evaluated the spatial variability and distribution of heterogeneous hydraulic conductivity (K) in the Choushui River alluvial fan in Taiwan, using ordinary kriging (OK) and mean and individual sequential Gaussian simulations (SGS). A baseline flow model constructed by upscaling parameters was inversely calibrated to determine the pumping and recharge rates. Simulated heads using different K realizations were then compared with historically measured heads. A global/local simulated error between simulated and measured heads was analysed to assess the different spatial variabilities of various estimated K distributions. The results of a MODFLOW simulation indicate that the OK realization had the smallest sum of absolute mean simulation errors (SAMSE) and the SGS realizations preserved the spatial variability of the measured K fields. Moreover, the SAMSE increases as the spatial variability of the K field increases. The OK realization yields small local simulation errors in the measured K field of moderate magnitude, whereas the SGS realizations have small local simulation errors in the measured K fields, with high and low values. The OK realization of K can be applied to perform a deterministic inverse calibration. The mean SGS method is suggested for constructing a K field when the application focuses on extreme values of estimated parameters and small calibration errors, such as in a simulation of contaminant transport in heterogeneous aquifers. The individual SGS realization is useful in stochastically assessing the spatial uncertainty of highly heterogeneous aquifers. Copyright © 2004 John Wiley & Sons, Ltd.
Experimental investigation of runoff reduction and sediment removal by vegetated filter strips
Authors: Abu‐Zreig Majed , Rudra Ramesh P. , Lalonde Manon N. , Whiteley Hugh R. , Kaushik Narinder K.
Published: March 2004

The impact of vegetated filter strips (VFS) on sediment removal from runoff has been studied extensively in recent years. Vegetation is believed to increase water infiltration and decrease water turbulence thus enhancing sediment deposition within filter media. In the study reported here, field experiments have been conducted to examine the efficiency of vegetated filter strips for sediment removal from cropland runoff. Twenty filters with varying length, slope and vegetated cover were used under simulated runoff conditions with an average sediment concentration of 2700 mg/L. The filters were 2, 5, 10 and 15 m long with a slope of 2·3 and 5% and three types of vegetation. Three other strips with bare soil were used as a control. The experimental results showed that the average sediment trapping efficiency of all filters was 84% and ranging from 68% in a 2‐m filter to as high as 98% in a 15‐m long filter compared with only 25% for the control. The length of filter has been found to be the predominant factor affecting sediment deposition in VFS up to 10 m. Increasing filter length to 15 m did not improve sediment trapping efficiency under the present experimental conditions. The rate of incoming flow and vegetation cover percentage has a secondary effect on sediment deposition in VFS. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of snow structure on water flow and solute transport
Authors: Waldner Peter A. , Schneebeli Martin , Schultze‐Zimmermann Ute , Flühler Hannes
Published: March 2004

Water flow through a melting snow pack modifies its structure and stability and affects the release of water and nutrients into soils and surface waters. Field and laboratory observations indicate a large spatial variability on various scales of the liquid water content and flow, a dominant system feature currently not included in numerical models. We investigated experimentally water and dye tracer movement through microstructurally different snow pack horizons and the persistence of preferential flow paths. Naturally rounded snow of varying grain size was artificially packed to obtain well known conditions by sieving it into rectangular bins. Surface melt was induced with infrared lamps. The flow paths were visualized with tracers and liquid water content was monitored with time domain reflectometry probes. Vertical cuts through the snow pack were imaged. The dye tracer patterns allowed the two flow regimes ‘matrix flow’ and ‘preferential flow’ to be distinguished. Matrix flow is apparently dominated by film and capillary flow in the unsaturated snow matrix. The capillary barrier effect at a boundary between a fine over a coarse textured layer on matrix flow in snow was confirmed. In contrast, preferential flow appears as well‐defined flow fingers that advance from 0·1 to 1 cm s−1. During a melt phase, the advancing flow fingers enlarge and are only partially time invariant. It remains to be shown whether the continuum concept, including the Darcy–Buckingham law is apt to describe the extremely non‐linear nature of water flow and the travel time of solutes in snow under conditions of melt water percolation. Probably, snow packs that include faceted crystals and large variations in bulk density, feature more pronounced capillary barriers and preferential flow triggering, but also stronger impeding of fingers by lateral dispersion. Further, triggering and persistence of preferential flow is complicated by the usually transient infiltration rate. Copyright © 2004 John Wiley & Sons, Ltd.
Short‐term spatial and temporal patterns of suspended sediment transfer in proglacial channels, small River Glacier, Canada
Authors: Orwin John F. , Smart C. C.
Published: March 2004

Alpine glacial basins are a significant source and storage area for sediment exposed by glacial retreat. Recent research has indicated that short‐term storage and release of sediment in proglacial channels may control the pattern of suspended sediment transfer from these basins. Custom‐built continuously recording turbidimeters installed on a network of nine gauging sites were used to characterize spatial and temporal variability in suspended sediment transfer patterns for the entire proglacial area at Small River Glacier, British Columbia, Canada. Discharge and suspended sediment concentration were measured at 5 min intervals over the ablation season of 2000. Differences in suspended sediment transfer patterns were then extracted using multivariate statistics (principal component and cluster analysis). Results showed that each gauging station was dominated c. 80% of days by diurnal sediment transfer patterns and ‘low’ suspended sediment concentrations. ‘Irregular’ transfer patterns were generally associated with ‘high’ sediment concentrations during snowmelt and rainfall events, resulting in the transfer of up to 70% of the total seasonal suspended sediment load at some gauging stations. Suspended sediment enrichment of up to 600% from channel storage release and extrachannel inputs occurred between the glacial front and distal proglacial boundary. However, these patterns differed significantly between gauging stations as determined by the location of the gauging station within the catchment and meteorological conditions. Overall, the proglacial area was the source for up to 80% of the total suspended sediment yield transferred from the Small River Glacier basin. These results confirmed that sediment stored and released in the proglacial area, in particular from proglacial channels, was controlling suspended sediment transfer patterns. To characterize this control accurately requires multiple gauging stations with high frequency monitoring of suspended sediment concentration. Accurate characterization of this proglacial control on suspended sediment transfer may therefore aid interpretation of suspended sediment yield patterns from glacierized basins. Copyright © 2004 John Wiley & Sons, Ltd.
Differential expression of MMP and uPA systems and prognostic relevance of their expression in esophageal squamous cell carcinoma
Authors: Yamashita Keishi , Tanaka Yoichi , Mimori Koshi , Inoue Hiroshi , Mori Masaki
Published: March 2004

Matrix metalloproteinase (MMP) is critical for carcinoma progression. In our study, we evaluated the prognostic significance of the major MMP family such as MMP‐3, MMP‐9, MMP‐11 and MT1‐MMP at the mRNA in 44 esophageal squamous cell carcinoma (ESCC) that were previously characterized for MMP‐7, MMP‐1 and MMP‐2, and their relation to urokinase system (uPA and uPAR). MT1‐MMP, MMP‐11 and MMP‐2 expressions are closely associated with each other, while MMP‐9 and uPAR expressions are inversely associated with the former group. There is no MMP related to clinicopathological factors; however, patients with high MT1‐MMP could show worse prognosis, as compared to those with low MT1‐MMP expression (p=0.01), as well as MMP‐11 did (p=0.02). Both MMP showed clear expression of carcinoma cells by immunohistochemistry. In patients with high MT1‐MMP, recurrence was more prominent (23/26: 88.5%) than those with low MT1‐MMP (7/18: 38.9%) (p=0.0016). In the 20 cases who died within 3 years, all 15 cases with high MT1‐MMP showed initial recurrence of distant metastasis, and the other 5 cases with low MT1‐MMP showed locoregional recurrence (p=0.000064). These results could indicate that there is a relevant mechanism of associated expression of clinically significant MMP and that among them, MT1‐MMP plays the most critical role in ESCC progression. © 2004 Wiley‐Liss, Inc.