bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of a Novel Organoiridium(I) Fluoro Complex
Authors: Gorol Michael , Mösch‐Zanetti Nadia C. , Roesky Herbert W. , Noltemeyer Mathias , Schmidt Hans‐Georg
Published: May 2004

Cyclooctadienefluorotriphenylphosphaneiridium(I) [IrF(C8H12)(PPh3)] (3) was prepared and its structure determined by single crystal X‐ray diffraction analysis. Complex 3 crystallises in the monoclinic space group P21/n. The lattice parameters are a = 931.9(3) pm, b = 1629.4(7) pm, c = 1592.9(7) pm, α = γ = 90°, β = 92.85(3)°. Number of molecules per unit cell is 4. The square planar iridium complex 3 exhibits an Ir−F bond length of 201.3(5) pm. 3 was obtained in Teflon tubes, whereas the use of glass vessels led to cyclooctadiene‐bis(triphenylphosphane)iridium(I)‐pentafluorosilicate(IV) ([Ir(C8H12)(PPh3)2][SiF5]) (4). The composition of 4 was confirmed by single crystal X‐ray diffraction analysis. 4 crystallises in the monoclinic space group P21/c. The lattice parameters are a = 1157.4(9) pm, b = 1864.4(9) pm, c = 1922.5(17) pm, α = γ = 90°, β = 96.16(7)°. The number of molecules per unit cell is 4. The square‐planar coordinated iridium cation [Ir(C8H12)(PPh3)2]+ is separated from the trigonal bipyramidal [SiF5]− anion by 461.1 pm (shortest Ir···F distance) and thus it is assumed that no interactions occur between the fluorine and iridium atoms. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Zinc Guanidinate Complexes and Their Application in Ring‐Opening Polymerisation Catalysis
Authors: Coles Martyn P. , Hitchcock Peter B.
Published: May 2004

The insertion reaction between 1 equiv. of carbodiimide, R′N=C=NR′, and the zinc bis(amide) [Zn{N(SiMe3)2}2] affords the homoleptic zinc(II) guanidinate compounds [Zn{(Me3Si)2NC(NR′)2}2] (3, R′ = iPr; 4, R′ = Cy) in preference to the monosubstituted compounds. Compound 3 also results from the protonation reaction of 1 equiv. of the neutral guanidine (Me3Si)2NC(NiPr)(NHiPr) (2) with [Zn{N(SiMe3)2}2] or ZnMe2. In contrast, the N‐dimethylguanidine analogue Me2NC(NiPr)(NHiPr) (1) reacts cleanly with 1 equiv. of ZnMe2 to afford the dimeric species [Zn{Me2NC(NiPr)2}Me]2 (5). Attempted protonation of the Zn−C bond in 5 with 2,6‐di‐tert‐butylphenol resulted in preferential reaction at the Zn−N bond and formation of the mixed (aryloxo)methyl complex [Zn(OAr)Me·{Me2NC(NiPr)(NHiPr)}] (6), isolated as the guanidine adduct. Heating of 6, in an attempt to promote methane elimination, afforded a small amount of the dimetallic complex [{Zn(OAr)}2(μ‐{Me2NC(NiPr)2})(μ‐NMe2)] (7) as a result of the extrusion of NMe2− from the guanidine‐based ligand. The amine‐elimination reaction between [Zn{N(SiMe3)2}2] and 1 equiv. of 1,3,4,6,7,8‐hexahydro‐2H‐pyrimido[1,2‐a]pyrimidine (hppH) proceeds smoothly to afford the mixed (guanidinate)(amide) complex [Zn(hpp){N(SiMe3)2}]2 (8), which forms a dimer in the solid state. Crystal structures of compounds 3−8 are reported and a preliminary study of the activity of 8 in the ring‐opening polymerisation of lactide is described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004
Can the cyclo‐P5 Ligand Introduce Basicity at the Transition Metal Center in Metallocenes? A Hybrid Density Functional Study on the cyclo‐P5 Analogues of Metallocenes of Fe, Ru and Os
Authors: Padma Malar E. J.
Published: May 2004

Density functional theory (DFT) calculations and natural population analysis (NPA) performed on metallocenes of Fe, Ru and Os triad reveal that the cyclo‐P5 ligand introduces basicity at the metal center. All‐electron calculations at the B3LYP/6‐311+G* level yield NPA charges of 0.28, −0.28 and −0.91 at the iron center in [FeCp2], [FeCp(η5‐P5)] and [Fe(η5‐P5)2], respectively. The same trend in the charges is observed even when the core electrons of the metal are replaced by effective core potentials (ECPs). The accumulation of negative charge at the metal center is found to be similar in the cyclo‐P5 analogues of ruthenocene and osmocene. Thus, for example, the net NPA charges on Ru and Os in the decaphosphametallocenes are predicted to be −0.6 to −0.9, respectively, at different levels of calculations involving ECPs. The natural orbital populations show a small transfer of electron density from each phosphorus atom to the metal center, leading to a significant build‐up of negative charge on the metal in [M(η5‐P5)2]; this is a new feature observed in the transition metals bound to cyclo‐P5 ring. This finding is indeed supported by the indirect evidence observed by Scherer and co‐workers from the diamagnetic behavior in an iridium derivative of Fe(P5), that the Fe atom is negatively charged while one of the P atoms is positively charged. Natural bond orbital analysis reveals that the extent of covalent bond formation between the metal and the ligand is more pronounced for the cyclo‐P5 than the cyclopentadienyl ligand. While Cp retains 56−68% of aromaticity, the P5 ring exhibits 26−51% aromaticity as compared to the free anionic rings. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Oxalato‐Bridged [CuIICrIII] and [MnIICrIII] Binuclear Complexes: Synthesis, Crystal Structures, Magnetic and EPR Investigations
Authors: Marinescu Gabriela , Visinescu Diana , Cucos Andrei , Andruh Marius , Journaux Yves , Kravtsov Victor , Simonov Yurii A. , Lipkowski Janusz
Published: May 2004

Two new heterobinuclear complexes, [(bipy)(C2O4)Cr(μ‐C2O4)Cu(Hfsaaep)(H2O)]·2H2O (1) and [(phen)(C2O4)Cr(μ‐C2O4)Mn(phen)2(N3)]·H2O (2) have been obtained by using bis(oxalato)chromium(III) anions, [Cr(AA)(C2O4)2]−, as building blocks [AA = 2,2′‐bipyridine (bipy); 1,10‐phenanthroline (phen)]. The crystal structures of the two complexes have been solved. These complexes comprise neutral oxalato‐bridged CrIII−CuII and CrIII−MnII units. The [Cr(AA)(C2O4)2]− anion acts as a bidentate ligand toward CuII in compound 1 and as a monodentate ligand toward MnII in compound 2. The copper(II) ion in 1 exhibits a slightly distorted square bipyramidal stereochemistry, with the aqua ligand and one of the bridging oxalato oxygen atoms disposed in the apical positions [Cu(1)−O(1w) = 2.360(3) Å and Cu(1)−O(4) = 2.504(2) Å]. The second bridging oxalato oxygen atom [Cu(1)−O(2) = 2.0747(18) Å] and the N,N,O‐type Hfsaaep ligand are located in the basal plane. The distance between the CrIII and CuII ions across the bridging oxalate unit is 5.506 Å. The MnII ion in compound 2 is hexacoordinate (two chelating phen ligands, one oxalato bridging oxygen, and one terminal azido group). The intermolecular CrIII···MnII distance is 5.257 Å. The magnetic properties of the two complexes have been investigated. The magnetic coupling between CrIII and CuII in 1 was found to be ferromagnetic (J = +1.4 cm−1). The nature of the ground state (S = 2) has been further confirmed by plotting the magnetization‐versus‐field curve. An antiferromagnetic interaction was found between CrIII and MnII in compound 2 (J = −1.9 cm−1). The magnetization‐versus‐field curve indicates the occurrence of a crossover between the Zeeman components: MS = −1 (ground state S = 1), MS = −2, from the first excited state (S = 2), and MS = −3, from the second excited state. The EPR spectra of the two compounds are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Reaction Chemistry of 1,4‐Dilithio‐1,3‐diene and 1‐Lithio‐1,3‐diene Derivatives
Authors: Xi Zhenfeng
Published: May 2004

The organolithium compounds, 1,4‐dilithio‐1,3‐diene and 1‐lithio‐1,3‐diene derivatives, show unprecedented reaction patterns with organic substrates. The 1,4‐dilithio‐1,3‐dienes react with aldehydes or ketones via deoxygenation of the C=O moieties to afford cyclopentadiene derivatives; pyridine derivatives are obtained in excellent yields when these organolithium reagents are treated with nitriles. In addition to novel reaction patterns, the experimental results have demonstrated that both the mono‐ and the dilithio reagents are synthetically useful building blocks. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Come together: longitudinal comparisons of Pettigrew's reformulated intergroup contact model and the common ingroup identity model in Anglo‐French and Mexican‐American contexts
Authors: Eller Anja , Abrams Dominic
Published: May 2004

Both Anglo‐French and Mexican‐American relations are embedded in histories of conflict. Within these intergroup contexts, two longitudinal field studies of contact tested Pettigrew's (1998) reformulated model of the intergroup contact theory and Gaertner and Dovidio's (2000) Common Ingroup Identity Model (CIIM). In Pettigrew's model, intergroup friendship is accorded a special role and the contact‐bias relation is mediated by changing behaviour, ingroup reappraisal, generating affective ties, and learning about the outgroup. Pettigrew's integration of the three central models of contact generalization into a time‐sequence holds that contact first elicits decategorization, then salient categorization, and finally recategorization. In the CIIM, these three levels of categorization—plus a fourth, dual identity—are conceptualized to be mediators in the contact‐bias relation. Results point to the crucial importance of intergroup friendship and underline the mediating roles of learning about the outgroup, behaviour modification, and generating affective ties, but not ingroup reappraisal in Pettigrew's model. As for the CIIM, in Study 1 interpersonal and intergroup levels were most central, while in Study 2 the dual identity and superordinate group levels were most effective. The implications of the findings are discussed with reference to the likely stability of these effects in different intergroup contexts. Copyright © 2004 John Wiley & Sons, Ltd.
The ‘why’ and ‘why not’ of job search behaviour: their relation to searching, unemployment experience, and well‐being
Authors: Vansteenkiste Maarten , Lens Willy , De Witte Siegfried , De Witte Hans , Deci Edward L.
Published: May 2004

Two studies (n = 273 and 254) used self‐determination theory (SDT) to examine unemployed people's motivation both to search and not to search for a job. The self‐regulation questionnaire format (Ryan & Connell, 1989) was used to assess participants' autonomous and controlled job‐search motivation (the ‘why’ of job search) as well as their amotivation for searching. Additionally, both autonomous and controlled motivation for not searching (the ‘why not’ of job search) was assessed. Results provide validity for these five motivational constructs and indicate, in line with SDT, that the constructs predicted reports of search behaviour, affective experiences, and well‐being. The addition of autonomous and controlled motivation for not searching contributed additional predictive power beyond the motivational constructs that focused only on searching. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization and Assessment of the Microjet Electrode as a Detector for HPLC
Authors: Cannan Susan , Unwin Patrick R.
Published: May 2004

The microjet electrode (MJE) is characterized as a detector for high performance liquid chromatography (HPLC). Voltammetric measurements of the oxidation of hydroquinone (HQ) allow mass transport to be determined for the MJE detector configuration, and the factors controlling the conversion efficiency of the device to be well understood. The current‐time response to the flow injection analysis of volumes of solution in the 10–80 μL range has been established, and the limit of detection of this method has been determined. The latter was found to approach that of UV absorbance measurements, which is particularly encouraging, given that HQ has a relatively strong chromophore (ε=2 290.8 cm−1 mol−1 L). This detection system is a robust and simple arrangement with the capability of analyzing large volumes of eluent at typical analytical HPLC flow rates.
The Modification of Screen‐Printed Carbon Electrodes with Amino Group and Its Application to Construct a H2O2 Biosensor
Authors: Gao Qiang , Yang Fan , Ma Ying , Yang Xiurong
Published: May 2004

Electrooxidation of thionine on screen‐printed carbon electrode gives rise to the modification of the surface with amino groups for the covalent immobilization of enzymes such as horseradish peroxidase (HRP). The biosensor was constructed using multilayer enzymes which covalently immobilized onto the surface of amino groups modified screen‐printed carbon electrode using glutaraldehyde as a bifunctional reagent. The multilayer assemble of HRP has been characterized with the cyclic voltammetry and the faradaic impedance spectroscopy. The H2O2 biosensor exhibited a fast response (2 s) and low detection limit (0.5 μM).
A Markov regime switching approach for hedging stock indices
Authors: Alizadeh Amir , Nomikos Nikos
Published: May 2004

In this paper we describe a new approach for determining time‐varying minimum variance hedge ratio in stock index futures markets by using Markov Regime Switching (MRS) models. The rationale behind the use of these models stems from the fact that the dynamic relationship between spot and futures returns may be characterized by regime shifts, which, in turn, suggests that by allowing the hedge ratio to be dependent upon the “state of the market,” one may obtain more efficient hedge ratios and hence, superior hedging performance compared to other methods in the literature. The performance of the MRS hedge ratios is compared to that of alternative models such as GARCH, Error Correction and OLS in the FTSE 100 and S&P 500 markets. In and out‐of‐sample tests indicate that MRS hedge ratios outperform the other models in reducing portfolio risk in the FTSE 100 market. In the S&P 500 market the MRS model outperforms the other hedging strategies only within sample. Overall, the results indicate that by using MRS models market agents may be able to increase the performance of their hedges, measured in terms of variance reduction and increase in their utility. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:649–674, 2004
Hedging, liquidity, and the competitive firm under price uncertainty
Authors: Wong Kit Pong
Published: May 2004

In this paper, the behavior of the competitive firm under price uncertainty when the firm has access to an intertemporally unbiased futures market is examined. Futures contracts are marked‐to‐market and thus require interim cash settlement of gains and losses. The firm is subject to a liquidity constraint in that it is forced to prematurely close its futures position on which the interim loss incurred exceeds a threshold level. It is shown that the liquidity constrained firm optimally opts for an under‐hedge should it be prudent. Furthermore, the prudent firm cuts down its optimal level of output in response to the presence of the liquidity constraint. As such, the liquidity risk created by the interim funding requirement of a futures hedge adversely affects the hedging and production decisions of the competitive firm under price uncertainty. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:697–706, 2004
Determinants of the relative price impact of unanticipated information in U.S. macroeconomic releases
Authors: Hess Dieter
Published: May 2004

The intraday response of T‐bond futures prices to surprises in headline figures of U.S. macroeconomic reports is investigated. Analyzing the time series properties and the information content of the macroeconomic news flow, the answer to the question, “What determines the relative price impact of releases?” is sought. Several types of information regarding inflation and economic strength are distinguished and the explanatory power of the type of information is tested against the alternative hypothesis that the timeliness of a release determines its impact. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:609–629, 2004
The impact of electronic trading on bid‐ask spreads: Evidence from futures markets in Hong Kong, London, and Sydney
Authors: Aitken Michael J. , Frino Alex , Hill Amelia M. , Jarnecic Elvis
Published: May 2004

During 1999 and 2000, three major futures exchanges transferred trading in stock index futures from open outcry to electronic markets: the London International Financial Futures and Options Exchange (LIFFE); the Sydney Futures Exchange (SFE); and the Hong Kong Futures Exchange (HKFE). These changes provide unique natural experiments to compare relative bid‐ask spreads of open outcry vs. electronically traded markets. This paper provides evidence of a decrease in bid‐ask spreads following the introduction of electronic trading, after controlling for changes in price volatility and trading volume. This provides support for the proposition that electronic trading can facilitate higher levels of liquidity and lower transaction costs relative to floor traded markets. However, bid‐ask spreads are more sensitive to price volatility in electronically traded markets, suggesting that the performance of electronic trading systems deteriorates during periods of information arrival. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:675–696, 2004
Pricing credit spread options under a Markov chain model with stochastic default rate
Authors: Kang Jangkoo , Kim Hwa‐Sung
Published: May 2004

This paper studies a Markov chain model that, unlike the existing models, has a stochastic default rate model so as to reflect real world phenomena. We extend the existing Markov chain models as follows: First, our model includes both the economy‐wide and the rating‐specific factors, which affect credit ratings. Second, our model allows both continuous and discrete movements in credit spreads, even when there exist no changes in credit ratings. Under these assumptions, we provide a valuation formula for a credit spread option, and examine its effects. This paper suggests a parsimonious model. As in J. Wei (2003), we find that rating‐specific factors are important. Also, discrete movements seem to play a larger role depending on the firm's credit rating. Finally, we show that a model, like the Kodera model, that uses only a common factor without allowing for discrete movements, may overprice credit spread put options. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:631–648, 2004
Mapping of a candidate colorectal cancer tumor‐suppressor gene to a 900‐kilobase region on the short arm of chromosome 8
Authors: Flanagan James M. , Healey Sue , Young Joanne , Whitehall Vicki , Trott Deborah A. , Newbold Robert F. , Chenevix‐Trench Georgia
Published: May 2004

Loss of heterozygosity (LOH) on 8p occurs at high frequencies in many tumor types, including colorectal carcinoma (CRC). We previously used microcell‐mediated chromosome transfer (MMCT) into the CRC cell line SW620 to map a ∼7.7‐Mb colorectal cancer–suppressor region (CRCSR) at 8p22–23.1. In the current study, we transferred small fragments of this CRCSR into SW620 to refine the region further. Two microcell hybrids containing a 321‐ to 898‐kb region around the D8S552 marker at 8p23.1 showed suppression of soft agar clonicity and tumorigenicity in athymic mice when compared to control cell lines. These data suggest that the putative colorectal tumor–suppressor gene is within this small region. We analyzed two candidate genes within this region: FLJ23749 and KIAA1456. Expression of both genes was detected in normal colonic crypt cells and in mucosa. Quantitative reverse transcriptase polymerase chain reaction showed downregulation of KIAA1456 in 9 of 12 primary colorectal tumors compared to matching normal mucosa, but normal or increased expression of FLJ23749. FLJ23749 was expressed in all CRC cell lines tested; however, KIAA1456 was downregulated in three cell lines, including SW620, and was restored in the suppressed microcell hybrids. 5′aza‐2′Deoxycytidine treatment of the downregulated cell lines restored expression of KIAA1456, but bisulfite genomic sequencing did not show a correlation between promoter methylation and expression. Forty percent of the primary tumors showed LOH at this CRCSR locus, and mutation analysis revealed somatic mutations in 1 of 88 primary colorectal tumors for both KIAA1456 and FLJ23749. Despite the rarity of somatic mutations, the expression data suggest that KIAA1456 is still a candidate for the putative 8p colorectal cancer tumor‐suppressor gene. © 2004 Wiley‐Liss, Inc.
Two independent RB1‐inactivating mutations in peripheral blood DNA of a hereditary retinoblastoma patient
Authors: Alonso Javier , Menéndez Ibis , López Andrés , Frayle Helena , Ruisánchez Nora , Pestaña Ángel
Published: May 2004

We report the presence of a hemizygous inactivating germ‐line RB1 mutation (a recurrent g.78250C→T transition, resulting in a stop codon in exon 17) in peripheral blood DNA from a patient with hereditary bilateral retinoblastoma. Hemizygosity was established by sequencing that showed no traces of the wild‐type C nucleotide and by quantitative real‐time PCR, which showed loss of one copy of exon 17. Genotyping of the RB1 locus with several polymorphic markers delineated a maximal deletion region between g.76875 and g.99426, including exons 15–17 and a large piece (21 kb) of intron 17. The heterozygosity for the mutation found in skin fibroblasts proves that the intragenic RB1 deletion probably took place in the definitive hematopoietic lineage of the patient. The presence of a null Rb−/− genotype in the hematopoietic cell lineage suggests that the white blood cells of the proband could be useful in the investigation of the role of complementary RBI family proteins in the control of the cell cycle. © 2004 Wiley‐Liss, Inc.
Helicobacter pyloriinfection activatesFOSand stress‐response genes and alters expression of genes in gastric cancer–specific loci
Authors: Myllykangas Samuel , Monni Outi , Nagy Bálint , Rautelin Hilpi , Knuutila Sakari
Published: May 2004

We studied human gene expression changes caused byHelicobacter pyloriinfection by using an in vitro model and 13k cDNA microarrays. A gastric cancer cell line was infected withH. pyloristrain NCTC 11637.H. pyloriinfection was found to induce differential expression of genes in chromosomal locations known to contain frequent chromosomal aberrations and gene mutations specific to gastric cancer. Based on the results of time series experiments, the primary transcription target of the infection seemed to beFOS, the expression of which significantly increased afterH. pyloriinfection.H. pyloriinfection also activated transcription of several stress‐response genes.H. pyloriinfection may predispose the host cell to DNA damage in the chromosomal locations specific to gastric cancer by activating transcription and promoting histone removal from these sites, thus exposing its target DNA to mutations. © 2004 Wiley‐Liss, Inc.
Enhanced cognitive performance and cheerful mood by standardized extracts of Piper methysticum (Kava‐kava)
Authors: Thompson Richard , Ruch Willibald , Hasenöhrl Rüdiger U.
Published: May 2004

The acute effects of the herbal anxiolytic Kava‐kava (Piper methysticum G. Forster) on emotional reactivity and cognitive performance were investigated in a double‐blind randomized placebo‐controlled trial involving healthy volunteers. Subjects' reports of mood change were assessed with the state‐trait‐cheerfulness‐inventory, which measures the three concepts of cheerfulness, seriousness and bad mood as both traits and states. Cognitive performance was examined with the Sperling partial report and the Sternberg item recognition task, which were used as an index for visual attention and short‐term memory processing. The intake of a single dose of Kava extract (300 mg; p.o.) led to an increase in state cheerfulness, while the phytopharmacon did not influence state seriousness and bad mood. The mood‐elevating effects of Kava were most prominent in trait cheerful subjects, indicating that trait cheerfulness moderated the drug‐induced increase in cheerful mood. Furthermore, Kava improved the accuracy and the speed of performing the partial report and the item recognition task, indicative of a beneficial effect of the phytopharmacon on visual attention and short‐term memory retrieval, respectively. Thus, unlike conventional benzodiazepine‐type anxiolytics, which tend to impair cognitive performance and to increase the occurrence of negative affective states, Kava is a potent anxiolytic agent, which, additionally, can facilitate cognitive functioning and can increase positive affectivity related to exhilaration. Copyright © 2004 John Wiley & Sons, Ltd.
Decrease of the platelet 5‐HT2A receptor function by long‐term imipramine treatment in endogenous depression
Authors: Gómez‐Gil Esther , Gastó Cristóbal , Carretero Marta , Díaz‐Ricart Maribel , Salamero Manel , Navinés Ricard , Escolar Ginés
Published: May 2004

Background

Animal studies have found that many antidepressants induce decreases in both the density and the functional activity of the serotonin 2A (5‐HT2A) receptor subtype. However, the extrapolation of findings to humans has been inconclusive. A physiological platelet response mediated by this receptor, the serotonin‐amplified platelet aggregation, was measured to study whether long‐term antidepressant treatment induces changes in 5‐HT2A receptor functioning in endogenous depressed patients.

Method

The percentage of serotonin‐amplified platelet aggregation to adenosine diphosphate (ADP) was studied in 15 untreated patients with major depressive disorder (DSM‐IV) with endogenous features (Newcastle scale). This index was used as an indirect measurement of the functional status of platelet 5‐HT2A receptors. Aggregation studies were repeated once remission of the symptoms was achieved during treatment with imipramine (150–300 mg/day). A group of 15 concurrent normal subjects was used as a control.

Results

A statistically significant decrease (p = 0.038) in the percentage of serotonin‐amplified platelet aggregation to ADP was observed when remission was achieved (after 145 ± 27 days).

Conclusions

The results showed a decrease in a platelet functional response mediated by 5‐HT2A receptors following effective imipramine treatment, suggesting that desensitization or down‐regulation of the 5‐HT2A receptor function could be linked to the therapeutic effect of some antidepressants. The data also support the use of platelet aggregometry as a surrogate measurement of antidepressant action, particularly in intra‐subject designs. Copyright © 2004 John Wiley & Sons, Ltd.
A preliminary study of the comparative effects of olanzapine and risperidone on cognition in schizophrenia
Authors: Kim Yang‐Tae , Kang Byung‐Jo
Published: May 2004

The aim of this study was to compare the effects of olanzapine and risperidone on cognitive functions in patients with schizophrenia. The subjects were schizophrenic outpatients, all meeting DSM‐IV diagnostic criteria for schizophrenia and already treated with risperidone. In the experimental group (15), risperidone was changed to olanzapine to be administered for 8 weeks. Risperidone was maintained without a change in the daily dose in the control group (13). The assessment of clinical symptoms and cognitive functions in both groups was made at baseline and at 8 weeks. The experimental group relative to the control group showed significant improvement in five items such as immediate and delayed recall of verbal memory, verbal fluency, visual memory and total error of executive function. Although these data are preliminary, they could suggest the possibility of cognitive benefits from treatment with olanzapine relative to risperidone. These findings did not appear to be mediated by changes in clinical symptoms and side effects. Copyright © 2004 John Wiley & Sons, Ltd.
Drug utilization review of risperidone for outpatients in a tertiary referral hospital in Singapore
Authors: Luo Nan , Koh Yvonne , Tan Chay Hoon , Kua Ee Heok , Li Shu Chuen
Published: May 2004

Background

Risperidone has been used in Singapore for schizophrenia since 1996. However, little information is available on its utilization pattern.

Objective

To examine the risperidone utilization pattern in the Psychiatric Outpatient Clinic of the National University Hospital.

Method

Medical records of all outpatients with schizophrenia prescribed with risperidone from 1 September1999 to 31 August 2000 were reviewed.

Results

A total of 417 risperidone prescriptions were dispensed for 130 outpatients (50 male, 80 female) during the study period. The mean ± SD daily doses for prescriptions and for patients were 2.3 ± 1.3 mg and 2.1 ± 1.1 mg, respectively. Among these patients, 28 (21.5%) received at least one concomitant conventional antipsychotic and 71 (54.6%) received a concomitant anti‐Parkinsonian agent. Logistic regression analysis suggested that a higher risperidone dose was associated with the greater probability of anti‐Parkinsonian agent usage.

Conclusions

The mean risperidone dose during the study period was towards the lower end of recommendation for schizophrenia. Further study is warranted to confirm and explain the pattern of low‐dose risperidone, and the high use of concomitant conventional antipsychotics and anti‐Parkinsonian agents in Singapore. Elucidation of these would provide a valuable insight for the management of Asian patients with schizophrenia using risperidone. However, the current data indicate that the practice of using a lower dose of risperidone could represent better affordability and an improved cost‐effectiveness ratio of risperidone compared with conventional antipsychotics in Asian patients. Copyright © 2004 John Wiley & Sons, Ltd.
Verbal working memory deficits in current and previous users of MDMA
Authors: Wareing Michelle , Fisk John E. , Murphy Philip , Montgomery Catharine
Published: May 2004

Previous research suggests that MDMA users are impaired in various aspects of cognitive functioning, however, it remains unclear whether they might experience deficits in established measures of verbal working memory functioning. In the present study current and previous MDMA users were compared with non‐users on verbal working memory measures including reading and computation span. Both user groups were found to be impaired on the computation span measure while current users also exhibited impairment in reading span. The MDMA‐related deficit on the computation span measure remained significant following the introduction of statistical controls for the potentially confounding effects of cannabis and other drugs. The results are discussed in the context of recent research on executive processes. It is suggested that MDMA may produce differential effects on specific components within a fractionated executive system. Copyright © 2004 John Wiley & Sons, Ltd.
Effects of dietary caffeine on mood when rested and sleep restricted
Authors: James Jack E. , Gregg M. Elizabeth
Published: May 2004

An Erratum has been published for this article in Human Psychopharmacology 20(5), 2005, 376.

Prolonged use of caffeine can lead to physical dependence evidenced by characteristic withdrawal symptoms during abstinence. Debate exists as to whether mood enhancement by caffeine represents a net effect or merely the restoration of abstinence‐induced mood decrements. One aim of this study was to determine the net effects on mood of dietary caffeine compared with prolonged abstinence. In addition, the study aimed to determine whether caffeine restores mood degraded by a non‐caffeine source, namely, sleep restriction. A double‐blind placebo‐controlled cross‐over design was employed in which 48 male and female volunteers alternated weekly between ingesting placebo and caffeine (1.75 mg/kg) three times daily for 4 consecutive weeks, while being either rested or sleep restricted. Mood was assessed using a computerized version of the profile of mood states (POMS), giving scores for overall mood and six mood dimensions. Gender had small effects on mood, whereas all mood dimensions were markedly adversely affected by sleep restriction. Caffeine had no significant net enhancing effects on mood when participants were rested, and produced no net restorative effects when mood was degraded by sleep restriction. On the contrary, caffeine‐induced decrements in mood were observed during both conditions of rest and sleep restriction. Copyright © 2004 John Wiley & Sons, Ltd.
Benchmarking performance in the irrigation and drainage sector: a tool for change
Authors: Malano Hector , Burton Martin , Makin Ian
Published: May 2004

With increasing pressure on available water resources, irrigation systems in many countries are having to find ways to improve performance. As often the main consumptive user, irrigation systems are having to release water for other uses and to produce “more crop per drop”. Benchmarking is a valuable tool that has proven itself in the business and commercial sector, as well as in public sector enterprises. This paper describes and defines the benchmarking process, and goes on to outline its current application in the irrigation and drainage (I&D) sector. The paper highlights the difficulty of benchmarking in the I&D sector given the complexity and site‐specific nature of irrigation and drainage systems, and emphasises the need for careful identification of which processes to benchmark. Preliminary benchmarking indicators are discussed, and attention drawn to efforts currently under way to apply and test this preliminary set. Emphasis is placed on the effort and resources required to bring about the required changes identified by the benchmarking exercise, and the role of change management as an integral part of the benchmarking process. The paper concludes that benchmarking provides a feasible mechanism for performance improvement in the I&D sector, but requires the active involvement of motivated individuals with support from the wider environment, encompassing an enabling socio‐political environment and support from key stakeholders. Copyright © 2004 John Wiley & Sons, Ltd.
Conceptualizing irrigation project modernization through benchmarking and the rapid appraisal process
Authors: Burt Charles M. , Styles Stuart W.
Published: May 2004

Benchmarking is defined as a systematic process for achieving continued improvement in the irrigation sector through comparisons with relevant and achievable internal or external goals, norms, and standards. The three aspects of benchmarking are: evaluation of technical indicators (both internal and external); appraisal of the system processes; and an evaluation of service to users and their satisfaction with that service.

The authors have incorporated all three components into a training program in which project staff learn the concepts of modernization and then evaluate their own project in a systematic rapid appraisal process (RAP). At the end of the training, internal and external indicators are developed for the project, and the local staff develop a priority list for modernization of the project. This paper will present the concepts of the RAP. Copyright © 2004 John Wiley & Sons, Ltd.
Applying benchmarking and data envelopment analysis (DEA) techniques to irrigation districts in Spain
Authors: Díaz J. A. Rodríguez , Poyato E. Camacho , Luque R. López
Published: May 2004

In this research, the application of data envelopment analysis (DEA) is proposed as a methodology to overcome the problems related to the lack of methodology to assign the correct weightings for the calculation of indexes and to the subjectivity of the interpretations of results. DEA is a linear programming technique to determine the relative efficiencies of a company when the inputs and outputs of production units within the company are known, but the productive process itself is not. In this way, quantitative efficiencies and the weighting of any performance indicator can be assessed and compared, permitting managers to obtain a well‐defined performance ranking. This is especially important when managers dispose of a limited budget. The results of the application of this methodology to Andalusian irrigation districts (Spain) are presented and discussed here. This study was used to select the most representative irrigation districts in Andalusia which were then studied in greater depth by applying the performance indicators selected by IPTRID for use by the benchmarking international program. Copyright © 2004 John Wiley & Sons, Ltd.
Present practices and opportunities for performance improvement of irrigation schemes in Maharashtra state of India (POPIIS)
Authors: Sodal S. V.
Published: May 2004

Maharashtra state has created approximately 3.7 Mha of irrigated potential since independence in 1947. However, the season wise utilization remains low with only 1.3 Mha being irrigated in 2000–01. In the ongoing efforts to increase utilization and improve service provision the state government has introduced a series of policies and procedures directed at improving rural livelihoods. Annual performance assessment has been a feature of irrigation management for the past 25 years based on five key parameters. Developing from these basic performance measures the state has joined national and international benchmarking programmes in the search for performance improvements.

The paper presents a summary of the development of performance assessment into benchmarking in Maharashtra state with examples of key indicators. Copyright © 2004 John Wiley & Sons, Ltd.
Benchmarking performance of irrigation schemes: a case study from Turkey
Authors: Cakmak Belgin , Beyri̇bey Mevlut , Yildirim Y. Ersoy , Kodal Suleyman
Published: May 2004

Benchmarking can be defined as the identification and application of organization specific best practices with the goal of improving competitiveness, performance and efficiency.

In this study, irrigation schemes of the State Hydraulic Works (DSİ) 10th Region were taken as material for benchmarking irrigation performance for the years between 1996 and 2000. Each system's performance is assessed using a number of indicators proposed by the IPTRID/World Bank study on benchmarking in the irrigation and drainage sector, and benchmark values for performance identified. Whilst further work is required, it is considered that this study provides a valuable starting point for benchmarking performance of irrigation systems in Turkey. This is seen as timely given the increasing demands being placed on the available water resources in the country. Copyright © 2004 John Wiley & Sons, Ltd.
Benchmarking of Australian irrigation water provider businesses
Authors: Alexander Peter J. , Potter Matthew O.
Published: May 2004

The Australian National Committee of the International Commission on Irrigation and Drainage (ANCID) has developed an effective and efficient process for benchmarking the irrigation water provider business in Australia. As of July 2003, ANCID has produced four annual financial year‐based benchmarking reports, which have been commended both within Australia and internationally. The 2001/2002 ANCID benchmarking report presented data on 65 performance indicators, across 40 separate water provider systems. The increased focus on business sustainability, resource management, as well as emerging confidentiality issues for the irrigation water provider business in Australia, has recently led to ANCID restructuring its benchmarking reporting arrangements. This restructuring has seen the adoption of a three‐tier reporting framework. The new framework will deliver the outputs currently sought by the users of the benchmarking data, including the irrigation water providers, industry regulators, water resource policy makers and the general community. The irrigation water provider benchmarking process in Australia is changing rapidly. This paper presents the situation as at July 2003. Copyright © 2004 John Wiley & Sons, Ltd.
Application of performance assessment and benchmarking tool to help improve irrigation system performance in Sri Lanka
Authors: Jayatillake H. M.
Published: May 2004

Performance improvement in irrigated agriculture in Sri Lanka is vital in view of the contribution it makes to the national economy, in addition to the livelihood of large numbers of people depending on irrigated agriculture and the competing demands that are emerging in the water resources sector. Taking into account the potential available for improvement in the irrigation sector, a performance assessment programme was initiated in 1997, starting with a smaller number of irrigation schemes gradually expanding to include other schemes. The indicators initially selected for assessment were simple but effective in categorizing schemes based on their performance and identifying where attention was required. Performance improvement interventions included both planning and management interventions. Continuation of the programme evolved into a programme of benchmarking where comparison of performance with other schemes or performance of the same scheme over a period was done and found to be effective as a tool for performance improvement.

By joining the ICID, IPTRID, FAO, WB and IWMI assisted benchmarking initiative in 2002, it is further expected that this activity can be done more formally and effectively. Copyright © 2004 John Wiley & Sons, Ltd.
Benchmarking of irrigation projects in Malaysia: initial implementation stages and preliminary results
Authors: Ghazalli Mohd Azhari
Published: May 2004

Malaysia has set itself a target of 65% self‐sufficiency level in rice production by the year 2010. Taking the population growth into account, each of the eight granaries has to increase its present output by about 50% in the next seven years. For the agricultural sector to achieve the new target, efficiency has to improve. An important first step in this direction is through the greater efficiency in water utilization for irrigation. As part of its strategy to improve productivity, the Department of Irrigation and Drainage has embarked on an effort to introduce benchmarking to the rice growing schemes.

Benchmarking in irrigation is a useful tool in the management of water. It enables evaluation of resource utilization, to evaluate performance against a target, as well as to compare against others. As a management tool, it is indispensable in the decision‐making process. This paper recounts the steps that were taken in the implementation of the benchmarking exercise, the progress achieved, as well the pitfalls that were encountered. It notes that while some headway has been made, much work remains to be done before a set of reliable benchmark indices for rice growing in the country is available. Copyright © 2004 John Wiley & Sons, Ltd.
In vivoevaluation of a biomimetic apatite coating grown on titanium surfaces
Authors: Vasudev Deepta Vani , Ricci John L. , Sabatino Christopher , Li Panjian , Parsons J. Russell
Published: May 2004

Osteoconductive mineral coatings represent an established technology for enhancing the integration of orthopedic implants with living bone. However, current coatings have limitations related to fabrication methods, attachment strength to metal substrates, and in vivo performance. Low temperature biomimetic growth is a coating technique wherein the device to be coated is immersed in a meta‐stable saturated solution of the coating constituents and growth of the coating is then allowed to proceed on the surface of the device. This study focused on thein vivoevaluation of a biomimetic apatite coating fabricated under these conditions. The experiment was designed to specifically test the amount of bone ingrowth into the coated channels versus the uncoated channels of an established bone chamber system, with emphasis placed on the amount of bone present on the coupon surface. Three types of measurements were taken on each channel: linear ingrowth %, area ingrowth %, and continuous bone apposition %. The experiments demonstrated that under controlled conditions, the apatite coating appears to resorb in 8 weeks and did stimulate early osseointegration with the metal surface with a reduction in fibrous tissue encapsulation. This coating may, therefore, be useful in facilitating early bone ingrowth into porous surfaces without the potential for coating debris, macrophage infiltration, fibrous tissue encapsulation, and eventual coating failure as may occur with current plasma‐sprayed hydroxapatite coating techniques. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 629–636, 2004
Human alveolar bone cell adhesion and growth on ion‐implanted titanium
Authors: Nayab S. N. , Jones F. H. , Olsen I.
Published: May 2004

Surface characteristics play a vital role in determining the biocompatibility of materials used as bone implants. Calcium ion implantation of titanium was previously reported to enhance osseointegration and bone formation in vivo, although the lack of consistent and reproducible effects highlight the need to understand the basic mechanisms involved in the response of target cells to such surfaces. The aim of this study was therefore to measure the precise effects of ion implantation of titanium on bone cells in vitro. Alveolar bone cells were seeded on the surface of polished titanium disks implanted with calcium, potassium, and argon ions. Using radioisotopically tagged bone cells, the results showed that although the calcium ion implanted surface reduced cell adhesion, it nevertheless significantly enhanced cell spreading and subsequent cell growth. In contrast, few differences in bone cell behavior were observed between the potassium‐ and argon‐implanted titanium and the control nonimplanted titanium disks. These findings suggest the possibility that the calcium‐implanted surface may significantly affect the biocompatibility of titanium implants by enhancing bone cell growth. Surface modification by ion implantation could thus prove to be a valuable tool for improving the clinical efficacy of titanium for bone repair and regeneration in vivo. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 651–657, 2004
Engineered allogeneic chondrocyte pellet for reconstruction of fibrocartilage zone at bone–tendon junction—A preliminary histological observation
Authors: Wong Margaret W. N. , Qin Lin , Tai Jenny K. O. , Lee Simon K. M. , Leung K.S. , Chan K. M.
Published: May 2004

This study examined histologically the potential of using allogeneic cultured chondrocyte pellet (CCP) in enhancing bone–tendon junction (BTJ) healing using a rabbit partial patellectomy model. Chondrocytes isolated from the cartilaginous ribs of 6‐week‐old New Zealand white rabbits were cultured for 14 days to form CCP. Partial patellectomy was performed on 30 18‐week‐old rabbits. After removal of the distal third patella, the BTJ gap was repaired surgically with or without CCP interposition. Four samples of patella–patellar tendon complexes (PPTC) for each group were harvested each at 8, 12, and 16 weeks; and two additional PPTC for each group were harvested at 2, 4, and 6 weeks for early observation of fibrocartilage zone regeneration, histologically. Results showed that CCP interposition demonstrated earlier structural integration at the BTJ after 8, 12, and 16 weeks of healing, and formation of a fibrocartilage zone like structure, compared with control specimens. In addition, no immune rejection was observed in CCP experimental group. The results suggested that CCP had a stimulatory effect on BTJ healing. This bioengineering approach might have potential clinical application in treatment of difficult BTJ healing. However, systemic histomorphometric, immunological tests, and biomechanical evaluations are needed before any clinical trials. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 362–367, 2004