bluuebunny/crossref_metadata_2025 huggingface dataset:
COLOR NORMALIZATION FOR COLOR OBJECT RECOGNITION
Authors: FINLAYSON GRAHAM D. , TIAN GUI YUN
Published: April 2003

Color images depend on the color of the capture illuminant and object reflectance. As such image colors are not stable features for object recognition, however stability is necessary since perceived colors (the colors we see) are illuminant independent and do correlate with object identity. Before the colors in images can be compared, they must first be preprocessed to remove the effect of illumination. Two types of preprocessing have been proposed: first, run a color constancy algorithm or second apply an invariant normalization. In color constancy preprocessing the illuminant color is estimated and then, at a second stage, the image colors are corrected to remove color bias due to illumination. In color invariant normalization image RGBs are redescribed, in an illuminant independent way, relative to the context in which they are seen (e.g. RGBs might be divided by a local RGB average). In theory the color constancy approach is superior since it works in a scene independently: color invariant normalization can be calculated post-color constancy but the converse is not true. However, in practice color invariant normalization usually supports better indexing. In this paper we ask whether color constancy algorithms will ever deliver better indexing than color normalization. The main result of this paper is to demonstrate equivalence between color constancy and color invariant computation.

The equivalence is empirically derived based on color object recognition experiments. colorful objects are imaged under several different colors of light. To remove dependency due to illumination these images are preprocessed using either a perfect color constancy algorithm or the comprehensive color image normalization. In the perfect color constancy algorithm the illuminant is measured rather than estimated. The import of this is that the perfect color constancy algorithm can determine the actual illuminant without error and so bounds the performance of all existing and future algorithms. Post-color constancy or color normalization processing, the color content is used as cue for object recognition. Counter-intuitively perfect color constancy does not support perfect recognition. In comparison the color invariant normalization does deliver near-perfect recognition. That the color constancy approach fails implies that the scene effective illuminant is different from the measured illuminant. This explanation has merit since it is well known that color constancy is more difficult in the presence of physical processes such as fluorescence and mutual illumination. Thus, in a second experiment, image colors are corrected based on a scene dependent "effective illuminant". Here, color constancy preprocessing facilitates near-perfect recognition. Of course, if the effective light is scene dependent then optimal color constancy processing is also scene dependent and so, is equally a color invariant normalization.
Risk factors for side-effects of isoniazid, rifampin and pyrazinamide in patients hospitalized for pulmonary tuberculosis
Authors: Schaberg T , Rebhan K , Lode H
Published: April 2003

The aim of this study was to determine the current incidence of side-effects severe enough to cause intolerance of standard antituberculosis therapy with isoniazid, rifampin and pyrazinamide in patients hospitalized as a result of pulmonary tuberculosis. Five hundred and nineteen patients with proven pulmonary tuberculosis, who initially received standard antituberculosis therapy, were retrospectively studied in the department of infectious diseases in a teaching chest hospital. The incidence of severe side-effects related to the therapy, which led to the definitive termination of one of the three standard drugs, was measured and the risk factors for intolerance were analysed. Final termination of either isoniazid, rifampin or pyrazinamide because of severe side-effects was necessary in 121 of the 519 patients (23%). The most severe side-effects leading to final termination of one drug were hepatotoxicity (11%), exanthema (6%), and arthralgia (2%). Pyrazinamide showed more severe side-effects (15%) than isoniazid (7%) and rifampin (1.5%). Significant risk factors for intolerance of the standard therapy following a multivariate analysis were a history of hepatitis (odds ratio (OR) 3.4; 95% confidence interval (95% CI) 1.6-7.6; p = 0.0026) and an age > or = 60 yrs (OR 1.9; 95% CI 1.2-3.2; p = 0.017). Both of these risk factors were also significantly associated with the intolerance of pyrazinamide (history of hepatitis: OR 2.5; 95% CI 1.4-4.3; p = 0.0045; age > or = 60 yrs: OR 2.1, 95% CI 1.3-3.5; p = 0.0029) but not of isoniazid and rifampin. The side-effects of standard antituberculosis therapy are frequent in hospitalized patients aged > or = 60 yrs or with a history of previous hepatitis, and are probably due to pyrazinamide rather than to isoniazid or rifampin.
A five year follow-up of lung function among chemical workers using flow-volume and impedance measurements
Authors: Keman S , Willemse B , Wesseling GJ , Kusters E , Borm PJ
Published: April 2003

Impedance of the respiratory system, measured using the forced oscillation technique (FOT), has repeatedly been proposed as a tool for occupational health screening. The aim of this study was to compare the outcome of impedance measurements and flow-volume curves, and to study relationships between lung function decline and specific exposures and smoking. Both measurements were applied in 136 chemical workers from seven main production/personnel groups during a 5 year follow-up (1990-1995). The prevalence of airway obstruction (forced expiratory volume in one second (FEV1) < 80% of predicted) at both time-points was about 5% but did not necessarily include the same subjects. The average decline in FEV1 over 5 yrs was 200 mL (predicted decline 160 mL). Although most impedance parameters correlated to flow-volume parameters in both years, a rapid 5 year decline of FEV1 (> 330 mL) was only accompanied by a significant decrease in the reactance at 8 Hz (X8) and an increase in the resonance frequency (f0). Interestingly, decline in FEV1 was significantly dependent on age, years of employment, pack-years, FEV1, and all impedance parameters at the start in 1990 (r = 0.35; p = 0.01). Similarly, the increase in f0 was significantly dependent on age, years of employment, pack-years, f0, FEV1, forced vital capacity (FVC), peak expiratory flow (PEF) and maximal mid-expiratory flow (MMEF) at the start (r = 0.56; p < 0.01). Those with a rapid decline in FEV1, were relatively more represented among acid workers (relative risk (RR) = 2.14), maintenance workers (RR = 2.1) and bulk/transport workers (RR = 1.78), but none of these was significant. Lung function, however, was significantly lower in the bulk/transport workers (n = 14) compared to the rest, based both on flow-volume (FEV1, FVC) and impedance (X8, f0) measurements. Smoking had a significant effect on most flow-volume parameters but only for frequency dependence among the impedance outcomes. It is concluded that alterations in impedance parameters do reflect changes in flow-volume curves induced by age. smoking and occupational exposure. Therefore, these data are a valuable extension to current cross-sectional data.
Peripheral and respiratory muscles in chronic heart failure
Authors: Stassijns G , Lysens R , Decramer M
Published: April 2003

It is well-established that in patients with congestive heart failure (CHF), exercise is limited by fatigue and shortness of breath. The poor correlation between the fatigue and indices of central haemodynamic function might indicate that peripheral muscle alterations contribute to impaired exercise capacity. Intrinsic abnormalities of the skeletal muscles have been suggested as a possible explanation. Since the shortness of breath correlates poorly with changes in lung function, changes in the respiratory muscles have been investigated. Studies have demonstrated diaphragmatic myopathy and atrophy similar, in part, to the changes in peripheral skeletal muscles. In CHF, type I (slow twitch) fibre atrophy is seen in respiratory as well as in peripheral muscles. The mechanism of these alterations remains to be elucidated. Studies into the mechanism of muscle dysfunction in congestive heart failure are relevant to the prospect of treatment of the changes in peripheral and respiratory muscles.
A case for serial examination of sputum inflammatory cells
Authors: Wong AG , Pavord ID , Sears MR , Hargreave FE
Published: April 2003

In the case reported, serial evaluation of sputum inflammatory cell counts made it possible to identify an unusual series of events in a man with eosinophilic bronchitis. The patient initially presented with a productive cough, which did not respond to treatment with antibiotics or high-dose inhaled corticosteroids. A diagnosis of eosinophilic bronchitis was made after demonstration of intense sputum eosinophilia. When inhaled corticosteroids were stopped, symptoms and sputum eosinophilia became worse and airway hyperresponsiveness developed. Both abnormalities were reversed by a course of prednisone. When the prednisone was stopped the productive cough recurred but on this occasion sputum examination suggested a different disease process and the symptoms resolved after a course of co-trimoxazole. The patient has subsequently remained well on no treatment with little or no sputum eosinophilia.
Lithium Acetate-Catalyzed Aldol Reaction between Aldehyde and Trimethylsilyl Enolate
Authors: Nakagawa Takashi , Fujisawa Hidehiko , Mukaiyama Teruaki
Published: April 2003

Lithium acetate-catalyzed aldol reaction between trimethylsilyl enolates and aldehydes proceeded smoothly in a DMF or pyridine solvent to afford the corresponding aldols in good to high yields under weakly basic conditions.
Heck Arylation of α,β‐Unsaturated Aldehydes
Authors: Nejjar A. , Pinel C. , Djakovitch L.
Published: April 2003

The Heck arylation of α,β‐unsaturated aldehydes is strongly dependent on the catalyst, the solvent and the base. Optimized conditions yielded either selectively cinnamyl derivatives (83%) or double arylation products (88% based on aryl conversion). A new α‐arylation of β,β‐disubstituted acrolein is also realized.
New Electrosynthesis of Arylboronic Esters from Aromatic Halides and Pinacolborane
Authors: Laza Carine , Duñach Elisabet
Published: April 2003

A novel synthesis of arylboronic esters by a reductive electrochemical coupling reaction between aromatic halides and pinacolborane (HBpin, pin=pinacolate) has been carried out leading to arylboronic esters in moderate to good yields.
Practical Olefin Metathesis in Protic Media under an Air Atmosphere
Authors: Connon Stephen J. , Rivard Michael , Zaja Mirko , Blechert Siegfried
Published: April 2003

The discovery that efficient olefin metathesis reactions involving previously challenging terminal olefin substrates are possible using novel and readily available catalyst systems in non‐distilled, non‐degassed protic media in air is reported.
Titelbild: [Cd16In64S134]44−: 31‐Å Tetrahedron with a Large Cavity (Angew. Chem. 16/2003)
Authors: Li Hailian , Kim Jaheon , O'Keeffe Michael , Yaghi Omar M.
Published: April 2003

Der hierarchische Aufbau eines [Cd16In64S134]44−‐Ions beginnt mit einem InS4‐Tetraeder (blau) und verläuft über ein Supertetraeder dieser Tetraeder und ein Supertetraeder aus Supertetraedern (zusätzliche Cd‐Atome weiß) zu einem Supertetraeder aus Super‐Supertetraedern, dessen voluminösen Hohlraum die gelbe Kugel verdeutlicht. Ebenfalls dargestellt ist die nächsthöhere Hierarchiestufe, das Sierpinski‐Tetraeder. Über Näheres informiert Sie die Zuschrift von O. M. Yaghi et al. auf S. 1863 ff.
The effects of social identification, norms and attitudes on use of outreach services by homeless people
Authors: Christian Julie , Abrams Dominic
Published: April 2003

The theory of planned behaviour, social identity theory and attitudes toward institutional authority were used to predict the uptake of outreach services over a 3‐week period in a prospective study of 126 homeless people in a major UK city. Consistent with previous research, subjective norm was an important predictor, but so were identification with support services and attitudes to authority. The effect of intention on behaviour was moderated by subjective norm, such that intention affected behaviour more when subjective norm was weak. Subjective norm was affected by identification with support services, which in turn, was predicted by identification with homeless people and attitude to authority. It is concluded that the role of social identity and social norms is of central importance in understanding uptake of outreach services among homeless people. Copyright © 2003 John Wiley & Sons, Ltd.
Led rather than leading? Research on homelessness in Britain
Authors: Pleace Nicholas , Quilgars Deborah
Published: April 2003

This article examines the history of British homelessness research and its politicization over the past 40 years. The relationship between homelessness research and policy has been developing since the 1960s, and by the 1990s the majority of research was undertaken within the policy arena. In part, this has arisen because of the way in which research has been funded in the UK, with funding being dominated by government or those seeking to criticize its policies. To varying degrees, this is also attributable to the acceptance of a homelessness paradigm, which was ultimately no more than an ideological construct, the ‘definitions’ of homelessness within British legislation. Fuelled by the growth of homelessness and an increase in charitable activity, the volume of research grew during the 1980s and 1990s, but without concurrent methodological and theoretical development. Recent academic critiques of British homelessness research are reviewed, including the movement towards re‐conceptualizating homelessness. Copyright © 2003 John Wiley & Sons, Ltd.
Thermography basket catheter: In vivo measurement of the temperature of atherosclerotic plaques for detection of vulnerable plaques
Authors: Naghavi Morteza , Madjid Mohammad , Gul Khawar , Siadaty Mir Said , Litovsky Silvio , Willerson James T. , Casscells S. Ward
Published: April 2003

We have developed an intravascular thermography basket catheter to measure the temperature of the vessel wall to locate foci of inflammation. Our 3 Fr thermography basket catheter is a thermocouple‐based catheter made of a nitinol expandable and externally controllable basket system loaded with nine small and flexible built‐in thermosensors. It is equipped with real‐time data acquisition software with a thermal resolution of 0.0001°C and a sampling rate of 20 readings per second. In 10 inbred cholesterol‐fed dogs with femoral (but not carotid) atherosclerosis, we found foci of warmth on the surface of atherosclerotic but not disease‐free regions (P < 0.05). Marked temperature heterogeneity was also observed in the aortas of atherosclerotic Watanabe rabbits but not in normal rabbits. The catheters showed satisfactory accuracy, reproducibility, and safety. If confirmed in further studies, it has the potential to be utilized in detection of vulnerable plaques. Cathet Cardiovasc Intervent 2003;59:52–59. © 2003 Wiley‐Liss, Inc.
Druckstoßabreinigung textiler und starrer Filtermedien: Abreinigungsrelevante Parameter
Authors: Leubner H. , Riebel U.
Published: April 2003

Zur Charakterisierung der Druckstoßabreinigung von textilen und starren Filterelementen in technischen Anlagen sowie in Filterprüfständen wurden bislang vor allem Tankdruck und Ventilöffnungsdauer als Kennwerte herangezogen, die aber wegen der Abhängigkeit des Abreinigungsimpulses von der gesamten Anlagengeometrie keine Übertragbarkeit zwischen verschiedenen Systemen ermöglichen. Es stellt sich daher die Frage, welche Kenngrößen eines Abreinigungsdruckimpulses relevant sind. Bei Kenntnis dieser Parameter könnte eine Laboranlage so eingestellt werden, dass sie das gleiche Abreinigungsverhalten zeigt wie eine technische Anlage. An einem Filterprüfstand, an dem wahlweise textile Filter oder starre Filterkerzen eingebaut werden können, sowie an einer für Herding‐alpha‐Kerzen entwickelten Technikumanlage wurden Untersuchungen zum Einfluss verschiedener Druckstoßparameter auf das Abreinigungsverhalten durchgeführt. Die charakteristischen Kenngrößen maximaler Überdruck, Druckstoß und Druckanstiegsgeschwindigkeit wurden für jeden Abreinigungsimpuls ermittelt und mit den erzielten Abreinigungsgraden korreliert. Als Ergebnis umfangreicher Regressionsanalysen wurde festgestellt, dass v. a. der erreichte Maximaldruck und die Druckanstiegsgeschwindigkeit beim Nulldurchgang der Abreinigungsimpulse für das Abreinigungsergebnis relevant sind. Für die Praxis sollten Abreinigungssysteme daher im Hinblick auf diese Größen optimiert werden.
Versatile Bis‐Propargylic Reactivity of Acetylenedicarbonyl−Cobalt Complexes with Neutral C‐Nucleophiles: Direct Synthesis of a Furyl‐α‐pyrone
Authors: Soleilhavoup Michèle , Maurette Luc , Lamirand Cécile , Donnadieu Bruno , McGlinchey Michael J. , Chauvin Remi
Published: April 2003

Double aldol reactions of the Co2(CO)6 complex of acetylenedicarbaldehyde with several enol ethers have been carried out and compared with the double Nicholas reactions of the corresponding bis(diethyl acetal) complex. The selectivity was found to depend on (i) the nucleophile, (ii) the solvent, and (iii) the number of equivalents of the auxiliary BF3·OEt2. While silyl enol ethers give mono‐ and 1,4‐bis‐dialkylation products only, trimethoxybenzene affords 1,1‐bis‐ and 1,1,4‐tris‐arylation products. In dichloromethane as solvent, the trimethylsilyl enol ether of acetophenone exhibits novel behaviour. In this solvent, and in the presence of an excess acid, the primary bis(aldol) product evolves to the Co2(CO)6 complex of 1‐phenyl‐4‐(5‐phenyl‐2‐furyl)‐but‐3‐yn‐1‐one and to 3‐(5‐phenyl‐2‐furyl)‐6‐phenyl‐2H‐pyran‐2‐one. These products are rationalised in terms of a common double aldol−cyclodehydration process, followed by α‐slippage of the µ‐Co2(CO)6 unit, and by a cyclocarbonylation−decomplexation process, respectively. Reaction of the trimethylsilyl enol ether of acetophenone with the homologous (dibenzoylacetylene)Co2(CO)6 complex led to Z‐3‐[(3,5‐diphenyl‐2‐furyl)methylene]‐2−3H‐benzofuran‐1‐one, apparently by an aromatic C−H bond activation. The structures of the pyrone and benzofuranone molecules were established either by X‐ray crystallography and/or by 2D NMR spectroscopy. A general mechanistic scheme is proposed to account for the versatility of these reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Flexible Routes to the 5‐Hydroxy Acid Fragment of the Cryptophycins
Authors: Phukan Prodeep , Sasmal Sanjita , Maier Martin E.
Published: April 2003

Two solutions to establishing the anti stereochemistry of the vicinal stereocenters in the 5‐hydroxy acid subunit of cryptophycin, based on initial Evans syn aldol reactions between an N‐(propionyl)oxazolidinone 4 and a C3 aldehyde, were developed. In the first route, the secondary hydroxy group was inverted by use of Mitsunobu reaction conditions, whereas the second route features an inversion of the methyl‐bearing stereocenter, achieved by reductive removal of the chiral auxiliary, elimination to afford the terminal alkene, and anti‐selective hydroboration. The aryl part can be attached either by Wittig−Horner olefination or by a modified Julia coupling. Both routes provide the hydroxy acid 16 in a very efficient manner. The substrate for the hydroboration, alkene 22, could also be obtained from (S)‐malic acid. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The Aldol‐Grob Reaction: Regioselective Synthesis of (E)‐Alkenes from Aldehydes and Ketones with Ytterbium Triflate Catalysis
Authors: Curini Massimo , Epifano Francesco , Maltese Federica , Marcotullio Maria Carla
Published: April 2003

A simple, good yielding and solvent‐free aldol‐Grob reaction sequence, catalysed by Yb(OTf)3 hydrate, affording (E)‐alkenes regioselectively from aldehydes and ketones is described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Transition Metal‐Assisted Transformations of Diversely Functionalized Dienynes
Authors: Marco‐Contelles José , Mainetti Emily , Fensterbank Louis , Malacria Max
Published: April 2003

We report the triphenyltin‐mediated free‐radical cyclization of 4‐ethynyl‐2,6,6‐trimethylocta‐1,7‐dien‐4‐ol (1) and 4‐ethynyl‐6,6‐dimethylocta‐1,7‐dien‐4‐ol (2), along with some chemical manipulations of the resulting stannylidene derivatives 3 and 7. The reaction of intermediates 3 and 7 with BuLi afforded the protodestannylated compounds 5 and 8, respectively, in good yield, while the reaction of the mixture of adducts 3 and 4 with iodine gave the chloro(diphenyl)stannylidene derivatives 6 and 6′. The palladium dichloride catalyzed reaction of dienyne 1 with tributyl(trimethylsilyl)stannane has also been described. All these cycloisomerization reactions were highly stereoselective, affording unique isomers at the newly formed stereocenters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Measles vaccination improves the equity of health outcomes: evidence from Bangladesh
Authors: Bishaia David , Koenig Michael , Khan Mehrab Ali
Published: April 2003

Objectives: This paper asks whether measles vaccination can reduce socioeconomic differentials in under five mortality rates (U5MR) in a setting characterized by extreme poverty and high levels of childhood mortality. Design: Longitudinal cohort study based on quasi experimental design. Setting: Data come from the phased introduction of a measles vaccine intervention in Matlab, Bangladesh in 1982. Subjects: There were 16 270 Bangladeshi children aged 9–60 months. Intervention: The intervention cohort received measles vaccine. Main outcome measures: Socioeconomic differentials in U5MR between the lowest and highest socioeconomic status (SES) quintiles in a cohort of 8135 vaccinated children and a cohort of unvaccinated age matched controls. Mantel–Haenszel rate ratios for the lowest to highest SES quintile were computed. SES was measured by factor analysis of maternal schooling, land holdings, dwelling size, and number of rooms. Results: The U5MR ratio of lowest SES to highest was 2.27 (95% CI=1.62–3.19) in the unvaccinated population and 1.42 (95%CI=0.94–2.15) in the vaccinated population. The difference between unvaccinated and vaccinated U5MR ratios was statistically significant (p<0.10) and robust across alternative measures of SES. Conclusion: Children from the poorest quintile were more than twice as likely to die as those from the least quintile in the absence of measles vaccination. Universal distribution of measles vaccination largely nullified SES related mortality differentials within a high mortality population of children. Copyright © 2002 John Wiley & Sons, Ltd.
The Aral Sea basin—rumors, realities, prospects
Authors: Dukhovny Victor A.
Published: April 2003

The Aral Sea basin has been for many years appearing in global and former Soviet mass media as an example of the rapacious attitude to nature on the part of socialist society. For the last 10 years Central Asia has been subsisting and surviving under conditions where the regional countries closely interact with the whole world community. Though the Aral Sea Program, which was laid down at the Paris meeting in 1994, remained generally unfulfilled, cooperation between Central Asian states as to joint water resources management has not only managed to survive but continues to develop. New rumors still continue to stigmatize the Aral Sea basin by overstressing current controversies that are allegedly ready to develop into a “war for water” in the region. As a matter of fact cooperation between the countries carried out by water management agencies and the Interstate Commission for Water Coordination (ICWC), which celebrated its tenth jubilee in February 2002, has been progressing regardless of complexities and differences in the environmental, social, political and natural situation in the countries and gaps between their levels of development. This cooperation enjoys the confidence of their future success, giving objective appraisal of achievements and drawbacks as well as ways to survive. Fair assessments and realistic approaches are needed on the part of those who are earnestly willing to help the region, and at the very least there should be noninterference and silence on the part of those who are not interested. Copyright © 2003 John Wiley & Sons, Ltd.
A computational study of interactions between acetic acid and water molecules
Authors: Yamabe Shinichi , Tsuchida Noriko
Published: April 2003

Density functional theory calculations were performed for the title reactions to elucidate the difference between the strong cyclic hydrogen bond of (MeCOOH)2 and the electrolytic dissociation, MeCOOH⇌MeCOO− + H+, as a weak acid. The association of water clusters with acetic acid dimers strengthens the cyclic hydrogen bond. A nucleophilic attack of the carboxylic carbon by a water cluster leads to a first zwitterionic intermediate, MeCOO− + H3O+ + (HO)3CMe. The intermediate is unstable and is isomerized to a neutral interacting system, MeCOOH…(HO)3CMe + H2O. The ethanetriol, (HO)3CMe is transformed to an acetic acid monomer. The monomer may be dissociated to give a second zwitterionic intermediate with reasonable proton‐relay patterns and energy changes. In proton relay reaction channels, H in MeCOOH is not an acidic proton but is always a hydroxy proton. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 939–947, 2003
Theoretical studies on the gas‐phase pyrolysis of 2‐phenoxycarboxylic acids: An ONIOM approach
Authors: Xue Ying , Kang Chun Ho , Kim Chan Kyung , Lee Ikchoon
Published: April 2003

Various ONIOM combinations—ONIOM(HF/6‐31G*: PM3), ONIOM(B3LYP/6‐31G*: PM3), ONIOM(MP2/6‐31G*: PM3), and ONIOM(MP2/6‐31G*: HF/3‐21G)—were applied to investigate thermal decomposition mechanisms of four 2‐phenoxycarboxylic acids (2‐phenoxyacetic acid, 2‐phenoxypropionic acid, 2‐phenoxybutyric acid, and 2‐phenoxyisobutyric acid) in the gas phase. All the transition states and intermediates of the reaction paths were optimized. The reaction pathway of four reactants yielding the phenol, CO, and the corresponding carbonyl compound was characterized on the potential energy surface and found to proceed stepwise. The first step corresponds to the elimination of phenol and the formation of α‐lactone intermediate through a five‐membered ring transition state, and the second step is the cycloreversion process of α‐lactone intermediate to form CO and the corresponding carbonyl compound. The reaction pathway of latter three compounds to produce the carboxylic acid and phenol via a four‐membered cyclic transition structure was also examined theoretically. Comparison with experiment indicates that the activation parameters for the fist reaction channel are accurately predicted at the ONIOM(MP2/6‐31G*: HF/3‐21G) level of theory. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 963–972, 2003
Feedback‐assisted three‐dimensional reconstruction of the left ventricle with MRI
Authors: Swingen Cory M. , Seethamraju Ravi Teja , Jerosch‐Herold Michael
Published: April 2003

Purpose

To develop and test a new technique for rapid, accurate three‐dimensional (3D) reconstruction of the left ventricle (LV) and calculation of its volume parameters, with images from multiple orientations and interactive feedback.

Materials and Methods

The ventricular surface was fit to a number of user‐placed guide points in magnetic resonance (MR) images using bivariate smoothing splines. A 3D model was reconstructed and the LV volumes were calculated at both end diastole (ED) and end systole (ES). This technique was validated using a phantom, and applied to studies of 18 patients and four volunteers (N = 22) imaged on a 1.5‐T clinical scanner. The results of the 3D method were compared to the standard 2D short‐axis slice summation technique, which is widely used for the analysis of cardiac function.

Results

There was excellent agreement between the computed volume of the phantom using the 3D modeling method and the actual volume (190.50 mL ± 3.06 mL, and 191.0 mL ± 2.5 mL, respectively). There was good correlation between the volumes calculated with our 3D model and the slice summation technique (ED volume (EDV) difference, 6.36% ± 8.99% [mean ± SD]; ES volume (ESV), 0.92% ± 14.75%; stroke volume (SV), 10.54% ± 13.95%; ejection fraction (EF), 4.22% ± 9.16%). The 3D method was found to be more accurate than the slice summation technique for calculating LV volumes and mass from images of different slice orientations. Variations in the parameters between the two separate orientations using the 3D model vs. the slice summation method were as follows: EDV: 2.11% ± 1.52% vs. 10.36% ± 9.33%; ES volume: 2.76% ± 1.64% vs. 6.39% ± 3.62%; SV, 3.02% ± 4.38% vs. 18.84% ± 15.30%; EF, 2.03% ± 2.16% vs. 8.58% ± 6.73%; and LV mass: 4.77% ± 2.41% vs. 24.59% ± 6.41%. Differences in the ES volume due to the inclusion or exclusion of the most basal slice were found to be lower with the 3D model (6.90% ± 3.83%) compared to the slice summation method (25.04% ± 6.15%).

Conclusion

3D models can be used to accurately determine ventricular volume parameters. Results can be obtained using images from a variety of orientations, providing greater flexibility during image acquisition and possibly reducing the number of images needed for analysis. Feedback is provided to assist the analysis by providing a continuous update of the LV shape and volume. This feature allows the user to determine LV parameters to a predefined accuracy or to terminate the analysis when the parameters are not changing. This method is not restricted to multislice cine imaging in a single or prescribed slice orientation, and can be used for quick, accurate, and interactive analysis of cardiac function. J. Magn. Reson. Imaging 2003;17:528–537. © 2003 Wiley‐Liss, Inc.
Comparing Strategies for the Synthesis of Polyolefinic Thermoplastic Elastomers via Macromonomer Incorporation
Authors: Haag Monica C. , Simon Leonardo C. , Soares Joao B. P.
Published: April 2003

The microstructure of polyolefinic thermoplastic elastomers made with a combination of two single‐site catalysts was analyzed by Monte Carlo simulation. The model can be used to describe the crystallizable fraction for both long‐chain branched polypropylene (aPP‐g‐iPP) and long‐chain branched ethylene/α‐olefin copolymers (PEαO‐g‐PE). The simulations showed that at levels of 7.5% of comonomer incorporation, PEαO‐g‐PE samples reach a similar crystallizability level of aPP‐g‐iPP. From a topological point of view, it was demonstrated that the fraction of free arms and inner segments tend to the limit of ½ for highly branched chains and that the fraction of free arms reaches its maximum value when the Y‐type chains are the predominant population. A mathematical correlation between the linear‐ and LCB catalyst probabilities was proposed to ensure the production of symmetrical branched chains.

Long‐chain branch architecture of PEαO‐g‐PE.

magnified image

Long‐chain branch architecture of PEαO‐g‐PE.
Effect of current and voltage leads on the superconducting properties of mesoscopic triangles
Authors: Morelle M. , Bruynseraede Y. , Moshchalkov V. V.
Published: April 2003

The superconducting/normal phase boundary of mesoscopic triangles is studied by transport measurements. The presence of voltage and current leads, intrinsic to transport measurements, may produce pronounced resistance peaks close to the normal/superconducting transition. These phenomena are explained by taking into account the presence of charge imbalance around superconducting/normal interfaces. The resistance peaks in the vicinity of Tc can be suppressed by choosing the right shape for the current and voltage contacts. The measured critical temperature Tc(H) is compared with recent theoretical curve obtained in the framework of the linearized Ginzburg–Landau theory. A good agreement between the theory and our experiments is found.
Activated escape over oscillating barriers: The case of many dimensions
Authors: Lehmann J. , Reimann P. , Hänggi P.
Published: April 2003

We present a novel path‐integral method for the determination of time‐dependent and time‐averaged reaction rates in multidimensional, periodically driven escape problems at weak thermal noise. The so obtained general expressions are evaluated explicitly for the situation of a sinusoidally driven, damped particle with inertia moving in a metastable, piecewise parabolic potential. A comparison with data from Monte‐Carlo simulations yields a very good agreement with our analytic results over a wide parameter range.
A Hierarchical QSAR Model for Urinary Excretion of Drugs in Humans as a Predictive Tool for Biotransformation
Authors: Manga Na'ngono , Duffy Judith C. , Rowe Philip H. , Cronin Mark T. D.
Published: April 2003

Of the many pharmacokinetic endpoints applicable to in silico screening, drug biotransformation seen as a hybrid, multi‐enzymatic disposition parameter, has been little addressed. The aim of this study was to model drug biotransformation, utilising metabolism data for a heterogeneous group of drugs. The data were the cumulative amount of unchanged drug excreted in the urine, expressed as percent of the intravenous dose, administered for 160 drugs. The data were categorised into classes according to excretion ranges. The cut‐off values between those ranges were defined so as to enable optimal modelling. For each drug, a total of 72 physicochemical and structural descriptors were calculated. Modelling of the drug metabolism data was attempted utilising a hierarchical approach comprising a set of rules combining both linear discriminant analysis and recursive partitioning. The model developed into a decision tree involving the following descriptors: LogD6.5, counts of H‐bond donors, ionisation potential, COSMIC total energy, electronic energy, counts of OH‐groups and COOH‐groups and the sum of the total net charges. Overall, this model assigned 90% of the compounds correctly to the categories of extensively, or non‐extensively, metabolised. The model was successfully validated using an external test set of 40 compounds.
Mitogenic activity of insulin in the culture of a trypanosome: duration and dose response
Authors: Mackintosh David , Coleman Kim , Davies Angela J
Published: April 2003

The effects of insulin on the in vitro growth characteristics of Trypanosoma granulosum were investigated. The insulin growth stimulus had a rapid onset with little or no lag phase but was relatively short lived, growth peaking typically on day 3 or 4 of culture. This contrasted with medium containing 10% foetal calf serum, normally used for in vitro culture of this trypanosome, which after a 3 day lag stimulated sustained log‐phase growth. Insulin demonstrated a biphasic dose response with maximum growth typically occurring at 3–10 μg/ml and a much reduced effect at higher concentrations. These findings suggest a possible role for host insulin and/or trypanosomal insulin‐like molecules in regulating parasite growth in vivo.
DPP IV resistance and insulin releasing activity of a novel di‐substituted analogue of glucose‐dependent insulinotropic polypeptide, (Ser2–Asp13)GIP
Authors: Gault V.A. , Irwin N. , Harriott P. , Flatt P.R. , O'Harte F.P.M.
Published: April 2003

Structure—function studies suggest that preservation of the N‐terminus and secondary structure of glucose‐dependent insulinotropic polypeptide (GIP) is important for biological activity. Therefore, a novel di‐substituted analogue of GIP, (Ser2–Asp13)GIP, containing a negatively charged Asp residue in place of an Ala in position 13, was synthesised and evaluated for in vitro biological activity. Incubation with dipeptidyl peptidase IV (DPP IV) showed the half‐lives of GIP and (Ser2–Asp13)GIP to be 2.3 and >4 h, respectively. Insulin releasing studies in clonal pancreatic BRIN‐BD11 cells demonstrated that (Ser2–Asp13)GIP (10−12to 10−7mol/l) was significantly less potent (60–90%; P<0.05 to P<0.001) than native GIP. The peptide failed to display antagonistic properties as it did not significantly alter insulin secretion when incubated in the presence of GIP (10−7 mol/l). These results demonstrate that despite increased resistance to DPP IV, substituting Ala in position 13 with a negatively charged Asp, thus producing the di‐substituted analogue (Ser2–Asp13)GIP, significantly reduces biological activity, most likely due to modifications within the secondary structure.
ROBUST MOSAICING USING ZERNIKE MOMENTS
Authors: BADRA FADY , QUMSIEH ALA , DUDEK GREGORY
Published: April 2003

This paper presents an approach to the registration of individual images to one another to produce a larger composite mosaic. The approach is based on the use of the moments of Zernike orthogonal polynomials to compute the relative scale, rotation and translation between the images. A preliminary stage involves the use of an attention-like operation to estimate potential approximate correspondence points between the images based on extrema of local edge element density. Experimental results illustrate that the technique is effective in a range of environments and over a broad range of image registration parameters. In particular, our method makes few assumptions regarding the image content and yet, unlike several alternative approaches, can perform registration for images with only a limited amount of overlap.
NEURAL NETWORK CLASSIFICATION OF SYMMETRICAL AND NONSYMMETRICAL IMAGES USING NEW MOMENTS WITH HIGH NOISE TOLERANCE
Authors: PALANIAPPAN R. , RAVEENDRAN P. , OMATU SIGERU
Published: April 2003

The classification of images using regular or geometric moment functions suffers from two major problems. First, odd orders of central moments give zero value for images with symmetry in the x and/or y directions and symmetry at centroid. Secondly, these moments are very sensitive to noise especially for higher order moments. In this paper, a single solution is proposed to solve both these problems. The solution involves the computation of the moments from a reference point other than the image centroid. The new reference centre is selected such that the invariant properties like translation, scaling and rotation are still maintained. In this paper, it is shown that the new proposed moments can solve the symmetrical problem. Next, we show that the new proposed moments are less sensitive to Gaussian and random noise as compared to two different types of regular moments derived by Hu.6 Extensive experimental study using a neural network classification scheme with these moments as inputs are conducted to verify the proposed method.
Altägyptische Rezepturen metrologisch neu interpretiert
Authors: Pommerening Tanja
Published: April 2003

Starting point of this article is a problem obvious to anybody who reads the medical papyri of ancient Egypt from the New Kingdom and the Late Period: the prescriptions contain two dyadic systems of notation for measures of capacity without specifying the unit of measurement, firstly the Horus eye fractions 1/2, 1/4, 1/8, 1/16, 1/32 and 1/64 which are unanimously assumed to refer to the single Heqat and secondly the ‘normal’ dyadic fractions from 1/2 to 1/128, which have been interpreted in widely different ways, as fractions of the Henu‐, the Ro‐, the single Heqat‐, the 5‐Ro‐ or the Dja‐measure, respectively. Interpretations suggested in translations and commentaries have remained inconclusive and unsatisfactory. Based on new findings and readings, the present study sets out to show that

•the hieratic Horus eye fractions in the medical papyri of the New Kingdom and the Late Period refer to the quadruple and not to the single Heqat;

•the ‘normal’ fractions refer to the smallest Horus eye fraction 1/64 quadruple Heqat which corresponds from the New Kingdom (at the latest) to 1 Dja;

•the units Dja and Henu are in a ratio of 5:8 and not of 2:3, this unusual ratio of 5:8 makes sense in Egyptian thought when expressed as 40:64; 40 Henu (= 1 Oipe = 1 quadruple Heqat) equal 64 Dja and therefore the complete Horus eye, the smallest fraction of the Horus eye, 1/64 is 1 Dja;

•hence, the capacity markings of the two complete vessels known to exist with marked volumes of 1 and 1/2 Henu and 1, 1/2, 1/4, 1/8, 1/16, 1/32 and 1/64 Dja, allow all relevant volumes to be measured which are required in the preparations mentioned in extant medical papyri.
Very Rapid Preparation of SmI2 by Sonic Treatment of Iodoform and Metallic Samarium
Authors: Concellón José M. , Rodríguez‐Solla Humberto , Bardales Eva , Huerta Mónica
Published: April 2003

A very rapid preparation of SmI2 by sonication of a mixture of metallic samarium and iodoform in THF is described. To prove the synthetic applications of the obtained SmI2 several high‐yielding reactions were carried out. Preliminary results for the generation of SmI2 in THF by sonication from diiodomethane, 1,2‐diiodoethane, or iodine are also described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Immobilization of heavy metals in soils using inorganic amendments in a greenhouse study
Authors: Friesl Wolfgang , Lombi Enzo , Horak Othmar , Wenzel Walter W.
Published: April 2003

The effect of red mud (10 g kg–1), a by‐product of the alumina industry, zeolite (20 g kg–1), a naturally‐occurring hydrous aluminosilicate, and lime (3 g kg–1) on metal lability in soil and uptake by fescue (Festuca rubra L.) (FEST) and amaranthus (Amaranthus hybridus L.) (AMA) was investigated in four different soils from Austria. The soil collection locations were Untertiefenbach (UNT), Weyersdorf (WEY), Reisenberg (REI), and Arnoldstein (ARN). The latter was collected in the vicinity of a former Pb‐Zn smelter and was highly polluted with Pb (12300 mg kg–1), Zn (2713 mg kg–1), and Cd (19.7 mg kg–1) by long‐term deposition. The other soils were spiked with Zn (700 mg kg–1), Cu (250 mg kg–1), Ni (100 mg kg–1), V (100 mg kg–1), and Cd (7 mg kg–1) salts in 1987. The two plant species were cultivated for 15 months. Ammonium nitrate (1 M) extraction was used in a soil : solution ratio of 1:2.5 to assess the influence of the amendments on the labile metal pools. The reduction of metal extractability due to red mud was 70 % (Cd), 89 % (Zn), and 74 % (Ni) in the sandy soil (WEY). Plant uptake in this treatment was reduced by 38 to 87 % (Cd), 50 to 81 % (Zn), and 66 to 87 % (Ni) when compared to the control. Sequential extraction revealed relative enrichments of Fe‐oxide‐associated metal fractions at the expense of exchangeable metal fractions. Red mud was the only amendment that decreased lability in soil and plant uptake of Zn, Cd, and Ni consistently. Possible drawbacks of red mud application (e.g., As and Cr concentration) remain to be evaluated.
Monte Carlo Simulation of Long‐Chain Branched Polyethylene Chains Synthesized with Dual‐Site‐Type Catalyst Systems
Authors: Beigzadeh Daryoosh
Published: April 2003

A Monte Carlo model for the polymerization of ethylene with long‐chain branch formation using dual‐site catalyst systems was developed. It was shown that, unlike single‐site catalyst systems, a detailed knowledge of the specifics of catalyst sites and reactor conditions is essential to determine the required probabilities. Therefore, a kinetic model was developed for a CSTR at steady state to simulate the polymerization process. A methodology was also proposed for the calculation of the seven required Monte Carlo model probabilities from the kinetic model. It was shown how the information obtained from the Monte Carlo model complemented the kinetic model results in mapping out the chain microstructure and modeling the polymerization reactor. Eight different dual‐site catalyst systems were simulated to evaluate the proposed methodology.

Flow chart of the computer program for the Monte Carlo model for the simulation of LCB chains with dual‐site catalyst systems.

magnified image

Flow chart of the computer program for the Monte Carlo model for the simulation of LCB chains with dual‐site catalyst systems.
Predicting Toxicity against the fathead Minnow by Adaptive Fuzzy Partition
Authors: Pintore Marco , Piclin Nadège , Benfenati Emilio , Gini Giuseppina , Chrétien Jacques R.
Published: April 2003

Recent progress in the development of powerful tools suitable to design and to classify large chemical libraries can be fruitfully extended also to the ecotoxicity domain. Amidst these methods, Fuzzy Logic concepts, based on the possibility to handle the “concept of partial truth”, constitute interesting approaches to developing general predictive models.
Liquid chromatography/tandem mass spectrometry for the identification and determination of trichothecenes in maize
Authors: Laganà Aldo , Curini Roberta , D'Ascenzo Giuseppe , De Leva Ilaria , Faberi Angelo , Pastorini Elisabetta
Published: April 2003

A reliable, sensitive and selective liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed to determine four trichothecene mycotoxins (nivalenol, deoxynivalenol, fusarenon X and 3‐acetyldeoxynivalenol) in maize. Sample preparation was performed by extracting the analytes with a mixture of acetonitrile and water, followed by a solid‐phase extraction with Carbograph‐4 cartridges as the purification step. For the LC/MS/MS analysis two interfacing systems, Turbo IonSpray (TISP) and atmospheric pressure chemical ionization (APCI), were compared in both negative and positive ion modes. LC and MS parameters were optimized to achieve better results and sensitivity. The effect of mobile phase modifiers such as ammonium acetate and formic acid on the ionization yield was also evaluated. The best results were obtained using the electrospray ionization (ESI) interface in negative ion mode and the multiple reaction monitoring mode (MRM) for the quantitation. The detection limits ranged between 10 ng/g for fusarenon X and 1.5 ng/g for deoxynivalenol. A linear working range was achieved with a standard deviation between 3 and 10% and recovery rates from the maize samples above 81%. The procedure was applied to the analysis of a set of maize samples collected from farms located in different areas of northern and central Italy. The investigated samples turned out to be contaminated primarily with deoxynivalenol and, to a minor extent, with its derivatives. Copyright © 2003 John Wiley & Sons, Ltd.
Exploring heterogeneity in tumour data using Markov chain Monte Carlo
Authors: de Gunst Mathisca C. M. , Dewanji Anup , Luebeck E. Georg
Published: April 2003

We describe a Bayesian approach to incorporate between‐individual heterogeneity associated with parameters of complicated biological models. We emphasize the use of the Markov chain Monte Carlo (MCMC) method in this context and demonstrate the implementation and use of MCMC by analysis of simulated overdispersed Poisson counts and by analysis of an experimental data set on preneoplastic liver lesions (their number and sizes) in the presence of heterogeneity. These examples show that MCMC‐based estimates, derived from the posterior distribution with uniform priors, may agree well with maximum likelihood estimates (if available). However, with heterogeneous parameters, maximum likelihood estimates can be difficult to obtain, involving many integrations. In this case, the MCMC method offers substantial computational advantages. Copyright © 2003 John Wiley & Sons, Ltd.