bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adlayer Structures of Binaphthyl Derivatives on Cu(111)
Authors: Han Mei-Juan , Zeng Qing-Dao , Wan Li-Jun , Bai Chun-Li 
Published: July 2003

Abstract
Adsorption of two binaphthyl derivatives on Cu(111) electrode were investigated by STM and cyclic voltammetry. Both molecules adsorbed on the Cu(111) electrode surface in 0.1 M HClO4 solution and formed well-defined adlayers with a (4 × 4) symmetry in the double layer potential region. With the high resolution STM images, the configurations of individual molecules were determined. According to the experimental results, structural models are proposed for the adlayers.
A Simple, Effective and Highly Selective Cleavage of 3-Methylbut-2-enyl (prenyl) Ethers Using p-Toluenesulfonic Acid
Authors: Babu K Suresh , Raju B China , Srinivas P V , Rao A Sridhar , Kumar S Praveen , Rao J Madhusudana 
Published: July 2003

Abstract
A highly selective cleavage of prenyl ethers has been achieved in high yields using p-toluenesulfonic acid under extremely mild conditions. This method is compatible with a wide variety of functional groups such as methyl, benzyl, allyl ethers and benzyl, methyl, prenyl esters present in the molecules.
Size Selective Synthesis of Surface-modified EuS Nanocrystals Using Pyridine and Their Physical Properties
Authors: Thongchant Supitcha , Hasegawa Yasuchika , Wada Yuji , Yanagida Shozo 
Published: July 2003

Abstract
The particle size of EuS nanocrystals was gradually increased by addition of pyridine to the reaction mixture of europium metal and hydrogen sulfide in liquid ammonia. The size effect of EuS nanocrystals was found in the absorption spectra for the first time. The size effect on the magnetic properties of the nanocrystals was also observed.
EuO Nanocrystal Formation under ArF Laser Irradiation
Authors: Hasegawa Yasuchika , Thongchant Supitcha , Kataoka Tomoharu , Wada Yuji , Yatsuhashi Tomoyuki , Nakashima Nobuaki , Yanagida Shozo 
Published: July 2003

Abstract
EuO (Europium(II) oxide) nanocrystals are prepared under irradiation by means of an ArF excimer laser. The formation of EuO nanocrystals with the clear lattice fringes was confirmed by TEM image. The crystal growth was monitored by the emission spectra.
Intercalation and Photochemical Behavior of Azobenzene Derivatives with Layered Polymer Crystals as the Organic Host
Authors: Oshita Shinya , Matsumoto Akikazu 
Published: July 2003

Abstract
A photofunctional organic solid was fabricated by the intercalation of azobenzene derivatives containing an amino group into poly(muconic acid) as the layered polymer crystals. The organic intercalation and photoisomerization behaviors depended on the structure of the spacer between the azobenzene and amino groups of the guest.
Acridine-bearing PNA for Efficient Protection of Designated Site of DNA from Nuclease S1
Authors: Ren Binzhi , Ye Sheng , Liang Xingguo , Komiyama Makoto 
Published: July 2003

Abstract
By using peptide nucleic acid (PNA) bearing an acridine at its N-terminus, a predetermined portion of DNA substrate was efficiently protected from nuclease S1. Promotion of the protecting activity by the acridine is remarkable enough to provide the target DNA fragment in high selectivity and yield.
Conversion of Vegetable Oil to Biodiesel Using Ultrasonic Irradiation
Authors: Stavarache Carmen , Vinatoru Mircea , Nishimura Rokuro , Maeda Yasuaki 
Published: July 2003

Abstract
The influence of low frequency ultrasounds (28 and 40 kHz) versus mechanical stirring on the transesterification reaction of neat vegetable oil with methanol under base-catalysis was studied and the results are presented. It was found that the optimized variables of 6:1 methanol/oil (mol/mol), 0.5% NaOH (wt/wt), and 40 kHz ultrasonic irradiation at 25 °C for 20 min gave a maximum isolated ester yield of 98%.
Radiation-induced Degradation of Nitrobenzene in Aqueous Solutions
Authors: Feng Shao-Hong , Zhang Shu-Juan , Yu Han-Qing , Li Qian-Rong 
Published: July 2003

Abstract
Both the efficiency and pathways of nitrobenzene degradation induced by γ-ray irradiation were significantly influenced by the addition of reactive species scavengers. Experimental results showed that the degradation of nitrobenzene was more favorable under oxidative conditions than under reductive conditions. Based on the product analysis by GC–MS, possible degradation mechanisms of nitrobenzene under both oxidative and reductive conditions were proposed.
Regioselective Radical Cyclization by Electrochemical Reduction Using an Arene Mediator. Environmentally Benign Method
Authors: Kurono Nobuhito , Honda Eiichi , Komatsu Fumikazu , Orito Kazuhiko , Tokuda Masao 
Published: July 2003

Abstract
Electrochemical reduction of 2-(but-3-enyl)-1-haloarenes in the presence of phenanthrene as a mediator generated the corresponding aryl radicals and gave cyclized products in good yields. Higher regio- and stereoselectivities than those of usual radical cyclization using AIBN-TBTH were achieved.
Nitrate Ion-sieve Properties of Layered Double Hydroxides
Authors: Tezuka Satoko , Chitrakar Ramesh , Sonoda Akinari , Ooi Kenta , Tomida Tahei 
Published: July 2003

Abstract
Layered double hydroxides (LDHs) with different kinds of metals in the brucite layer were prepared and their anion exchange properties were studied batchwise. A nitrate ion-sieve property was observed for LDHs depending on the basal spacing of the brucite layer. The distribution coefficient of nitrate ion was a maximum on the Ni–Fe type LDHs having a basal spacing of 0.81 nm.
Enantiomerically Convergent Synthesis of Phosphatidyl-d-myo-inositol 3,5-Bisphosphate from Both l- and d-1,2-O-Cyclohexylidene-myo-inositol
Authors: Han Fushe , Hayashi Minoru , Watanabe Yutaka 
Published: July 2003

Abstract
The synthesis of phosphatidyl-d-myo-inositol 3,5-bisphosphate [PtdIns(3,5)P2] has been conveniently accomplished via convergent routes starting from both enantiomers, 1,2-O-cyclohexylidene-myo-inositol. The synthetic strategy involves completely regioselective phosphorylation of 3,4-diol and 2,3,6-triol of the suitably protected inositols with the corresponding phosphite in the presence of pyridinium tribromide and 2,6-lutidine, resulting in the formation of 3-O-phosphorylated products, respectively.
Naphthoquinone and Iridoid with NGF-potentiating Activity from Verbena littoralis
Authors: Li Yushan , Satake Masayuki , Oshima Yasukatsu , Ohizumi Yasushi 
Published: July 2003

Abstract
One new naphthoquinone, (4R)-4,9-dihydroxy-8-methoxy-α-lapachone (1), and two new iridoids, 7a-hydroxygelsemiol (2) and 6-methoxysemperoside (3) were isolated from Verbena littoralis H. B. K. 1 (3-30 μM) and 2 (3 μM) showed a markedly enhancing activity of nerve growth factor (NGF)-mediated neurite outgrowth from PC12D cells.
An Effective System to Synthesize Arylacetones. Substrate-ionic Liquid-ultrasonic Irradiation
Authors: Yinghuai Zhu , Bahnmueller Stefan , Hosmane Narayan S , Maguire John A 
Published: July 2003

Abstract
Manganese(III) acetate-promoted aromatic acetonylation has been accomplished with ultrasonic irradiation in ionic liquids, [N-n-pentyl-4-picolinium] [closo-CB11H12] (1), [OMIM] [BF4] and [BMIM] [PF6] in 62-93% yields, with excellent chemical selectivity.
Microwave-polythiol Method. A New Route to Preparation of Tellurium with Various Morphologies
Authors: Zhu Ying-Jie , Hu Xian-Luo 
Published: July 2003

Abstract
A new microwave-polythiol method has been developed for preparation of tellurium (Te) with various morphologies. 1,2-Ethanedithiol (EDT) was used as both a reducing reagent and a solvent. Reduction of TeO2 by EDT was achieved by microwave-heating at ≤140 °C for 30 min. The morphology of Te could be controlled by changing experimental parameters.
Electrocardiographic and Cardiovascular Effects of the 5-Hydroxytryptamine3 Receptor Antagonists
Authors: Navari Rudolph M , Koeller Jim M 
Published: July 2003

OBJECTIVE: To review the electrocardiographic (ECG) and cardiovascular effects of 5-hydroxytryptamine3 (5-HT3) receptor antagonists preclinically, in healthy volunteers, and in patients undergoing chemotherapy or surgery. DATA SOURCES: A MEDLINE search was performed of clinical trials and preclinical data published between 1963 and December 2002 assessing the ECG and cardiovascular effects of 5-HT3 receptor antagonists, supplemented with reviews and secondary sources. STUDY SELECTION AND DATA EXTRACTION: All of the articles identified were evaluated and all information deemed relevant was included in this review. DATA SYNTHESIS: There are no clinically relevant differences in efficacy and safety among the available 5-HT3 receptor antagonists for prevention and treatment of chemotherapy-induced and postoperative nausea and vomiting. As a class, they have well-defined electrophysiologic activity. Changes in ECG parameters (PR, QRS, QT, QTc, JT intervals) are small, reversible, clinically insignificant, and independent of the patient population studied, and patients are asymptomatic during these changes. ECG changes are most prominent 1–2 hours after a dose of dolasetron, ondansetron, and granisetron and return to baseline within 24 hours. Clinically important adverse cardiovascular events associated with these changes are rare. No serious cardiac events (including torsade de pointes) arising from ECG interval changes have been attributed to 5-HT3 receptor antagonist use. CONCLUSIONS: Clinical data demonstrate that ECG interval changes are a class effect of the 5-HT3 receptor antagonists. Theoretical concern regarding cardiovascular adverse events with these agents is not supported by clinical experience. The significant benefits of these agents outweigh the theoretical small risk of meaningful cardiovascular events.
Conditional Inference Following Group Sequential Testing
Authors: Ohman Strickland Pamela A. , Casella George 
Published: July 2003

AbstractThe work ofFisher(1959) andBuehler(1959) discuss the importance of conditioning on recognizable subsets of the sample space. The stopping time yields an easily identifiable partition of the sample space when considering group sequential testing. We first present confidence intervals that are correct when conditioning on the subset of data for which a trial stopped at a particular analysis. These intervals have very desirable properties for observations that are highly unusual (given any value of the mean). In addition, they provide insight into how information about the mean is distributed between the two sufficient statistics. We then use conditional coverage probabilities to compare the sample mean, stagewise, and repeated confidence intervals. We find that none of these intervals outperforms the others when conditioning on stopping time, and no interval is a uniformly acceptable performer.
Estimation of Heritability in Heteroscedastic One‐Way Unbalanced Random Model
Authors: Singh B. 
Published: July 2003

AbstractA modified estimator of heritability is proposed under heteroscedastic one way unbalanced random model. The distribution, moments and probability of permissible values (PPV) for conventional and modified estimators are derived. The behaviour of two estimators has been investigated, numerically, to devise a suitable estimator of heritability under variance heterogeneity. The numerical results reveal that under balanced case the heteroscedasticity affects the bias, MSE and PPV of conventional estimator, marginally. In case of unbalanced situations, the conventional estimator underestimates the parameter when more variable group has more observations and overestimates when more variable group has less observations, MSE of the conventional estimator decreases when more variable group has more observations and increases when more variable group has less observations and PPV is marginally decreased. The MSE and PPV are comparable for two estimators while the bias of modified estimator is less than the conventional estimator particularly for small and medium values of the parameter. These results suggest the use of modified estimator with equal or more observations for more variable group in presence of variance heterogeneity.
Inference for the Break Point in Segmented Regression with Application to Longitudinal Data
Authors: Piepho H.P. , Ogutu J.O. 
Published: July 2003

AbstractThis paper considers inference for the break point in the segmented regression or piece‐wise regression model. Standard likelihood theory does not apply because the break point is absent under the null hypothesis. We use results by Davies for this type of non‐standard set‐up [Biometrika 64 (1977), 247–254 and 74 (1987), 33–43] to obtain a test for the null hypothesis of no break point. A confidence interval can be constructed provided replicate data are available. The methods are exemplified using two longitudinal datasets, the one from ecology, the other from pharmacology.
Quantile Inference with Multivariate Failure Time Data
Authors: Yin Guosheng , Cai Jianwen , Kim Jinheum 
Published: July 2003

AbstractQuantiles, especially the medians, of survival times are often used as summary statistics to compare the survival experiences between different groups. Quantiles are robust against outliers and preferred over the mean. Multivariate failure time data often arise in biomedical research. For example, in clinical trials, each patient in the study may experience multiple events which may be of the same type or distinct types, while in family studies of genetic diseases or litter matched mice studies, failure times for subjects in the same cluster may be correlated. In this article, we propose nonparametric procedures for the estimation of quantiles with multivariate failure time data. We show that the proposed estimators asymptotically follow a multivariate normal distribution. The asymptotic variance‐covariance matrix of the estimated quantiles is estimated based on the kernel smoothing and bootstrap techniques. Simulation results show that the proposed estimators perform well in finite samples. The methods are illustrated with the burn‐wound infection data and the Diabetic Retinopathy Study (DRS) data.
More Powerful Likelihood Ratio Tests for Isotonic Binomial Proportions
Authors: Tebbs Joshua M. , Swallow William H. 
Published: July 2003

AbstractBinomial group testing involves pooling individuals into groups and observing a binary response on each group. Results from the group tests can then be used to draw inference about population proportions. Its use as an experimental design has received much attention in recent years, especially in public‐health screening experiments and vector‐transfer designs in plant pathology. We investigate the benefits of group testing in situations wherein one desires to test whether or not probabilities are increasingly ordered across the levels of an observed qualitative covariate, i.e., across strata of a population or among treatment levels. We use a known likelihood ratio test for individual testing, but extend its use to group‐testing situations to show the increases in power conferred by using group testing when operating in this constrained parameter space. We apply our methods to data from an HIV study involving male subjects classified as intraveneous drug users.
Comparison of Diagnostic Accuracy of Biomarkers With Pooled Assessments
Authors: Liu Aiyi , Schisterman Enrique F. 
Published: July 2003

AbstractNew biomarkers are frequently being developed in laboratory settings for the early diagnosis of diseases. However, the assay can be so expensive to assess in some cases that the evaluation of a large number of assays becomes unfeasible. Under this setting pooling biospecimens becomes an appealing alternative. In this paper, we present the methodology to allow for general pooling strategies and different data structures, which include balanced and unbalanced pooling cases. An estimate of the area under the ROC curve of a single biomarker with its asymptotic mean and variance is provided. Furthermore, we develop a test statistic for comparing the areas under the ROC curves of two biomarkers. The methods are illustrated with data from a study evaluating biomarkers for coronary heart disease.
Reducing ethnic prejudice: an evaluation of seven recommended principles for incorporation in public campaigns
Authors: Vrij Aldert , Akehurst Lucy , Smith Beverley 
Published: July 2003

AbstractThe present study investigated the effects of seven principles drawn from cognitive models of ethnic prejudice, general information processing models and persuasion models, on levels of ethnic prejudice. It was hypothesized that exposure to cue cards incorporating these principles would result in lower levels of prejudice than cue cards which did not incorporate the principles. A total of 400 caucasian participants were randomly assigned to experimental conditions (where participants were exposed to a cue card incorporating or omitting each of the seven principles), or the control condition (with no cue card exposure), and completed a questionnaire measuring ethnic prejudice. Results revealed that the absence of the principles in the cards led in several cases to unwanted negative effects (higher levels of prejudice than the control group). Reasons for these findings and implications for launching poster campaigns to reduce ethnic prejudice are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
O2 Evolution in the Fenton Reaction
Authors: Buda Francesco , Ensing Bernd , Gribnau Michiel C. M. , Baerends Evert Jan 
Published: July 2003

AbstractWe investigated the mechanism involved in the oxygen production in the Fenton chemistry by means of density functional theory calculations. This study extends previous work in which we proposed that the FeIVO2+ complex is the key active intermediate in the Fenton reaction. Here we provide a consistent picture of the entire reaction cycle by analyzing how the active species, FeIVO2+, can react with hydrogen peroxide to produce O2 and regenerate the Fe2+ catalyst. These results are also relevant in view of the analogies with important enzyme‐catalyzed oxidation reactions.
Control of Calcium Carbonate Polymorphism and Morphology through Biomimetic Mineralization by means of Nanotechnology
Authors: Ichikawa Kazuhiko , Shimomura Noriyuki , Yamada Masanori , Ohkubo Naoki 
Published: July 2003

AbstractIn vitro biomimetic mineralization by means of nanotechnology allows the formation of calcium carbonate polymorphs at low temperatures (<25 °C) under a CO2 atmosphere of 500–1500 ppm . A two‐dimensional zinc‐ion ordered array (zinc array), which acts as an active‐site mimic of carbonic anhydrase, has been prepared by immersing the self‐organized monolayer of 3‐(2‐imidazolin‐1‐y)propyltriethosilane on mica (ImSi substrate) into aqueous zinc solution. The zinc array mounted on the ImSi substrate catalyzed the conversion from CO2 to HCO3−, and accelerated the formation of calcium carbonate. In situ X‐ray diffraction data of the formed calcium carbonate on the poly(L‐aspartate)‐coated chitin substrate (pAsp substrate), with calcium ion‐recognition sites, demonstrated that the interaction between the zinc array and pAsp substrates formed both vaterite and calcite at low temperature (15 °C) and mainly vaterite at 25 °C; this interaction also controlled the morphology of calcium carbonate formed on pAsp substrate.
Polynuclear Palladium Complexes with 3,5‐Dimethylpyrazolate Exhibiting Three Different Coordination Modes
Authors: Forniés Juan , Martín Antonio , Sicilia Violeta , Martín L. Francisco 
Published: July 2003

AbstractThe characterisation of dinuclear pyrazolato‐bridged PdII complexes, [{Pd(μ‐dmpz)Cl(Hdmpz)}2] (1) and [{Pd(μ‐dmpz)(dmpz)(Hdmpz)}2] (2) (Hdmpz=dimethylpyrazole), has been carried out. An X‐ray study of compound 2 reveals the existence of intramolecular NH⋅⋅⋅N hydrogen bonds between neighbouring dmpz groups. Compound 2 has been deprotonated and both acidic hydrogen atoms substituted by two metal atoms of CuI, AgI or AuI to give the tetranuclear compounds [Pd2M2(μ2‐dmpz‐κN,N′)6] (M=Cu, Ag, Au). The structure of these compounds resembles a box with a small cavity inside. There are also three π‐electron‐rich clefts between each of the three pairs of azolato rings, capable of further complexation. The reactions of [Pd2M2(μ2‐dmpz‐κN,N′)6] (M=Cu, Ag, Au) with AgClO4 render compounds of the type [{Pd2M2(μ2‐dmpz‐κN,N′)2(μ3‐dmpz‐κN,N′,C4)4Ag2(μ2‐O2ClO2)}2] (M=Cu, Ag, Au). The X‐ray structures of crystals obtained from a solution of compounds [{Pd2M2(μ2‐dmpz‐κN,N′)2(μ3‐dmpz‐κN,N′,C4)4Ag2(μ2‐O2ClO2)}2] (M=Ag, Au) in acetone reveals a [{Pd2M2(μ2‐dmpz‐κN,N′)2(μ3‐dmpz‐κN,N′,C4)4Ag(OCMe2)(OClO3)Ag(μ2‐O2ClO2)}2] stoichiometry, indicating that only two of the three π‐electron‐rich clefts have been used to accommodate Ag+ ions. Each of the silver atoms are located in between two 3,5‐dmpz rings and are η1‐bonded to the C4 atom of each group.
Absolute Potassium Cation Affinities (PCAs) in the Gas Phase
Authors: Lau Justin Kai‐Chi , Wong Carrie Hoi Shan , Ng Po Shan , Siu Fung Ming , Ma Ngai Ling , Tsang Chun Wai 
Published: July 2003

AbstractThe potassium cation affinities (PCAs) of 136 ligands (20 classes) in the gas phase were established by hybrid density functional theory calculations (B3‐LYP with the 6‐311+G(3df,2p) basis set). For these 136 ligands, 70 experimental values are available for comparison. Except for five specific PCA values—those of phenylalanine, cytosine, guanine, adenine (kinetic‐method measurement), and Me2SO (by high‐pressure mass spectrometric equilibrium measurement)—our theoretical estimates and the experimental affinities are in excellent agreement (mean absolute deviation (MAD) of 4.5 kJ mol−1). Comparisons with previously reported theoretical PCAs are also made. The effect of substituents on the modes of binding and the PCAs of unsubstituted parent ligands are discussed. Linear relations between Li+/Na+ and K+ affinities suggest that for the wide range of ligands studied here, the nature of binding between the cations and a given ligand is similar, and this allows the estimation of PCAs from known Li+ and/or Na+ affinities. Furthermore, empirical equations relating the PCAs of ligands with their dipole moments, polarizabilities (or molecular weights), and the number of binding sites were established. Such equations offer a simple method for estimating the PCAs of ligands not included in the present study.
Coordinated and Clathrated Guests in the ${_{\infty }^{3}}$[Hg6As4]4+ Bicompartmental Framework: Synthesis, Crystal and Electronic Structure, and Properties of the Novel Supramolecular Complexes [Hg6As4](CrBr6)Br and [Hg6As4](FeBr6)Hg0.6
Authors: Olenev Andrei V. , Oleneva Olga S. , Lindsjö Martin , Kloo Lars A. , Shevelkov Andrei V. 
Published: July 2003

AbstractTwo new supramolecular complexes [Hg6As4](CrBr6)Br (1) and [Hg6As4](FeBr6)Hg0.6 (2) have been prepared by the standard ampoule technique and their crystal structures determined. Both crystallize in the cubic space group Pa$\bar 3$ with the unit cell parameter a=12.275(1) (1) and 12.332(1) Å (2), and Z=4. Their structures consist of bicompartmental, three‐dimensional [Hg6As4]4+ frameworks with cavities of two different sizes occupied by guest anions of different type. The bigger cavities are filled with the octahedral MBr6n− ions (M=Cr or Fe; n=3 or 4), whereas the smaller cavities trap either Br− ions (1) or Hg0 (2). The analysis of the host–guest contacts has allowed a classification of the octahedral guests as coordinated and the monatomic guests as clathrated. Magnetic measurements and ESR spectroscopy data have given information about the interaction between the host and guests. Band structure calculations (HF and hybrid DFT level) indicate that both 1 and 2 are non‐metallic, with a band gap of approximately 1.5 eV (B3LYP), and that the interaction between the host and guests is of predominantly electrostatic character. It is shown that though the electrostatic host–guest interaction is weak it plays an important role in assembling the perfectly ordered supramolecular architectures.