bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rational model for chiral recognition in a silica‐based chiral column: chiral recognition of N‐(3,5‐dinitrobenzoyl)phenylglycine‐terminated alkylsilane monolayer by 2,2,2‐trifluoro‐1‐(9‐anthryl)ethanol derivatives by chemical force microscopy
Authors: Otsuka Hideyuki , Arima Takayuki , Koga Tomoyuki , Takahara Atsushi 
Published: April 2005

AbstractDirect measurement of the chemical force between chiral molecules was investigated by chemical force microscopy (CFM). 2,2,2‐Trifluoro‐1‐(9‐anthryl)ethanol (TFAE) and N‐(3,5‐dinitrobenzoyl)phenylglycine (DNBP), a well‐known pair of enantiomers, were strongly immobilized on the surface of the cantilever tip and the substrate surface, respectively, by the use of aminosilane, to propose a chiral stationary phase model system of a silica‐based chiral column. The modification of TFAE on a cantilever tip and DNBP on the substrate surface was confirmed by x‐ray photoelectron spectroscopic and time‐of‐flight secondary ion mass spectrometric measurements. The force curve between (R or S)‐TFAE and (R or S)‐DNBP enantiomers were measured using the force measurement mode scanning force microscopy to determine the magnitude of the interaction. The histograms of the adhesion force for a different chirality pair [(R)‐ATEA vs (S)‐DNBP and (S)‐ATEA vs (R)‐DNBP] showed a broader distribution than those for the identical chirality pair [(R)‐ATEA vs (R)‐DNBP and (S)‐ATEA vs (S)‐DNBP]. Since CFM measurement cans recognize the difference of in nanonewton forces, the results can be regarded as a rational design for chiral recognition in a silica‐based chiral column. Copyright © 2005 John Wiley & Sons, Ltd.
Experimental and theoretical studies of 2,5‐diphenyl‐1,4‐distyrylbenzenes with all‐cis‐ and all‐trans double bonds: chemical structure determination and optical properties
Authors: Xie Zengqi , Yang Bing , Liu Linlin , Li Mao , Lin Dong , Ma Yuguang , Cheng Gang , Liu Shiyong 
Published: April 2005

Abstract2,5‐Diphenyl‐1,4‐distyrylbenzene (DPDSB) with all‐cis (cis‐DPDSB) and all‐trans double bonds (trans‐DPDSB) were synthesized by Wittig reaction and the differences in structural and optical properties between the cis‐ and trans‐isomers are discussed in detail. Both compounds were fully characterized by NMR spectroscopy, FT‐IR spectroscopy, x‐ray crystallography, differential scanning calorimetry (DSC) and electrochemical methods. X‐ray analysis and molecular simulation revealed that the structure of cis‐DPDSB obviously deviates from planarity along both the distyrylbenzene and terphenyl directions, and less intermolecular interaction exists in crystal. The cis‐isomer shows a large blue shift in the absorption spectrum in comparison with that of the trans‐isomer, and cyclic voltammetric measurements give bandgaps of 3.16 and 2.97 eV for cis‐ and trans‐DPDSB, respectively. Both compounds show unusually strong blue fluorescence in the solid state, probably due to the weak intermolecular interaction existing in both isomers owing to the large steric hindrance induced by the substituted phenyl groups. DSC experiments determined that both isomers have excellent thermal stability, which indicates that they can be used as active layers to make stable devices. Quantum chemical calculations for the frontier molecular orbital and the cation and anion properties reveal that the HOMO and LUMO are completely localized in the distyrylbenzene direction and the distyrylbenzene segment has more sensitive electroactivity than the terphenyl segment whether it is cis‐ or trans‐DPDSB. Copyright © 2005 John Wiley & Sons, Ltd.
An algebraic treatment of procedure refinement to support mechanical verification
Authors: Back Ralph-Johan , Preoteasa Viorel 
Published: April 2005

Abstract.
We introduce a new algebraic model for program variables, suitable for reasoning about recursive procedures with parameters and local variables in a mechanical verification setting. We give a predicate transformer semantics to recursive procedures and prove refinement rules for introducing recursive procedure calls, procedure parameters, and local variables. We also prove, based on the refinement rules, Hoare total correctness rules for recursive procedures, and parameters. We introduce a special form of Hoare specification statement which alone is enough to fully specify a procedure. Moreover, we prove that this Hoare specification statement is equivalent to a refinement specification. We implemented this theory in the PVS theorem prover.
Parental care behavior in the monogamous, sexually dimorphic Madagascar paradise flycatcher: sex differences and the effect of brood size
Authors: Mizuta Taku 
Published: April 2005

AbstractI studied the parental care behavior of the Madagascar paradise flycatcherTerpsiphone mutatain northwestern Madagascar. I especially focused on feeding, brooding and vigilance behaviors. Feeding rate did not differ between males and females, but females spent more time at the nest than males. Females dedicated their time to brooding, while males perched on the nest and were vigilant. Both parents changed the feeding rate in relation to brood size, so the feeding rate per nestling was not different among nests of different brood size. Duration of brooding by females increased with decreasing brood size, suggesting that the Royama effect, the pattern of lower feeding rate per nestling in larger broods, did not apply in this study. Males spent more time on vigilance than females. Anti‐predator vigilance by males should be important for nestling survival given the high predation pressure typical of this population. In conclusion, males provide considerable parental care probably to minimize nestling starvation and to avoid nest predation. My results are not consistent with the general pattern of less parental effort by males in monogamous, sexually dimorphic species.
Localization and changes of intraneural inflammatory cytokines and inducible‐nitric oxide induced by mechanical compression
Authors: Kobayashi Shigeru , Baba Hisatoshi , Uchida Kenzo , Shimada Seiichiro , Negoro Kouhei , Takeno Kenichi , Yayama Takafumi , Yamada Shuichi , Yoshizawa Hidezo 
Published: April 2005

AbstractStudy design: Investigation of intraneural inflammation induced by mechanical compression.Objectives: In order to investigate the mechanism of neuropathy, this study used a median nerve compression model in dogs. Immunohistochemistry was used to examine the localization and changes of inflammatory cytokines and nitric oxide (NO).Summary of background data: The manifestation of pain at sites of inflammation has a close relationship with the release of mediators from macrophages such as interleulin‐1 (IL‐1) and tumor necrosis factor‐α (TNF‐α), as well as with NO. However, the mediators involved in inflammation of nerve due to mechanical compression remain almost unknown.Methods: In this study, the median nerve of dogs was compressed with a clip for three weeks to observe the changes caused by compression. Immunohistochemistry was done by the avidin‐biotin‐peroxidase complex method to observe the changes of T cells (CD45) and macrophages (Mac‐1) after compression. Antibodies against IL‐β, TNF‐α, and inducible nitric oxide synthesis (i‐NOS) were used to examine the localization and changes of these mediators caused by nerve compression.Results: In control animals, resident T cells were detected, but there were no macrophages. IL‐1β was positive in the Schwann cells and vascular endothelial cells. However, no cells showed TNF‐α or i‐NOS positively. After nerve compression, numerous T cells and macrophages appeared among the demyelinized nerve fibers. The macrophages were positive for IL‐1β, TNF‐α and i‐NOS.Conclusion: Inflammatory cytokines and NO may be involved in intraneural inflammatory changes arising from mechanical compression. Such mediators may be of importance in the manifestation of neuropathy. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Expression patterns of hedgehog signaling peptides in naturally acquired equine osteochondrosis
Authors: Semevolos Stacy A. , Strassheim M. Lisa , Haupt Jennifer L. , Nixon Alan J. 
Published: April 2005

AbstractHypertrophic differentiation and endochondral ossification of growth cartilage are regulated by a complex array of signaling peptides, including parathyroid hormone‐related protein (PTH‐rP), Indian hedgehog (Ihh), and bone morphogenetic proteins (BMPs). This study investigated the expression of Ihh, Patched1 and 2 (Ptc1, Ptc2), Smoothened (Smo), Gli1, and Gli3, in naturally acquired articular osteochondrosis, using an equine model. Cartilage was harvested from osteochondrosis (OC) affected femoropatellar or scapulohumeral joints from immature horses and normal control horses of similar age. Ihh, Ptc1, Smo, Gli1, and Gli3 mRNA expression levels were evaluated by real‐time quantitative PCR. Spatial tissue expression was determined by in situ hybridization for Ihh and Smo and immunohistochemistry for Ptc1 and Ptc2. The expression of Ihh was significantly increased in OC cartilage compared to normal control cartilage and was localized mainly to the deep layer of articular cartilage, just above the calcified zone, with some mild expression also present in the middle cartilage layer. The expression of Gli1 was significantly decreased in OC samples, but there was no significant difference in expression of Gli3, Ptc1 and Smo in OC cartilage compared to normal cartilage. The expression of Ptc1 protein was present at the junction of deep and calcified layers, while Ptc2 protein was expressed throughout the middle, deep, and calcified cartilage layers. Spatial expression of Smo was variable between animals and confined mainly to the middle and deep layers when present. Half of the OC samples displayed areas of moderate to strong Smo expression compared to mild or minimal expression in normal controls. The increased Ihh expression in OC suggests a role of Ihh in diseased cartilage, although it is not known if a PTH‐rP/Ihh feedback cycle exists in articular cartilage. The disparity between increased Ihh expression and decreased Gli1 expression in OC cartilage suggests a different primary transcription factor for Ihh or the presence of an elevated Ihh inhibitor in these tissues. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Total variation and level set methods in image science
Authors: Tsai Yen-Hsi Richard , Osher Stanley 
Published: April 2005

We review level set methods and the related techniques that are common in many PDE-based image models. Many of these techniques involve minimizing the total variation of the solution and admit regularizations on the curvature of its level sets. We examine the scope of these techniques in image science, in particular in image segmentation, interpolation, and decomposition, and introduce some relevant level set techniques that are useful for this class of applications. Many of the standard problems are formulated as variational models. We observe increasing synergistic progression of new tools and ideas between the inverse problem community and the ‘imagers’. We show that image science demands multi-disciplinary knowledge and flexible, but still robust methods. That is why the level set method and total variation methods have become thriving techniques in this field.Our goal is to survey recently developed techniques in various fields of research that are relevant to diverse objectives in image science. We begin by reviewing some typical PDE-based applications in image processing. In typical PDE methods, images are assumed to be continuous functions sampled on a grid. We will show that these methods all share a common feature, which is the emphasis on processing the level lines of the underlying image. The importance of level lines has been known for some time. See, e.g., Alvarez, Guichard, Morel and Lions (1993). This feature places our slightly general definition of the level set method for image science in context. In Section 2 we describe the building blocks of a typical level set method in the continuum setting. Each important task that we need to do is formulated as the solution to certain PDEs. Then, in Section 3, we briefly describe the finite difference methods developed to construct approximate solutions to these PDEs. Some approaches to interpolation into small subdomains of an image are reviewed in Section 4. In Section 5 we describe the Chan–Vese segmentation algorithm and two new fast implementation methods. Finally, in Section 6, we describe some new techniques developed in the level set community.
Unfolding crystallins: The destabilizing role of a β‐hairpin cysteine in βB2‐crystallin by simulation and experiment
Authors: Macdonald James T. , Purkiss Andrew G. , Smith Myron A. , Evans Paul , Goodfellow Julia M. , Slingsby Christine 
Published: April 2005

AbstractThe thermodynamic and kinetic stabilities of the eye lens family of βγ‐crystallins are important factors in the etiology of senile cataract. They control the chance of proteins unfolding, which can lead to aggregation and loss of transparency. βB2‐Crystallin orthologs are of low stability and comprise two typical βγ‐crystallin domains, although, uniquely, the N‐terminal domain has a cysteine in one of the conserved folded β‐hairpins. Using high‐temperature (500 K) molecular dynamics simulations with explicit solvent on the N‐terminal domain of rodent βB2‐crystallin, we have identified in silico local flexibility in this folded β‐hairpin. We have shown in vitro using two‐domain human βB2‐crystallin that replacement of this cysteine with a more usual aromatic residue (phenylalanine) results in a gain in conformational stability and a reduction in the rate of unfolding. We have used principal components analysis to visualize and cluster the coordinates from eight separate simulated unfolding trajectories of both the wild‐type and the C50F mutant N‐terminal domains. These data, representing fluctuations around the native well, show that although the mutant and wild‐type appear to behave similarly over the early time period, the wild type appears to explore a different region of conformational space. It is proposed that the advantage of having this low‐stability cysteine may be correlated with a subunit‐exchange mechanism that allows βB2‐crystallin to interact with a range of other β‐crystallin subunits.
Crystal structures of apo wild‐type M. jannaschii tyrosyl‐tRNA synthetase (TyrRS) and an engineered TyrRS specific for O‐methyl‐L‐tyrosine
Authors: Zhang Yan , Wang Lei , Schultz Peter G. , Wilson Ian A. 
Published: April 2005

AbstractThe Methanococcus jannaschii tRNATyr/TyrRS pair has been engineered to incorporate unnatural amino acids into proteins in E. coli. To reveal the structural basis for the altered specificity of mutant TyrRS for O‐methyl‐l‐tyrosine (OMeTyr), the crystal structures for the apo wild‐type and mutant M. jannaschii TyrRS were determined at 2.66 and 3.0 Å, respectively, for comparison with the published structure of TyrRS complexed with tRNATyr and substrate tyrosine. A large conformational change was found for the anticodon recognition loop 257–263 of wild‐type TyrRS upon tRNA binding in order to facilitate recognition of G34 of the anticodon loop through π‐stacking and hydrogen bonding interactions. Loop 133–143, which is close to the tRNA acceptor stem‐binding site, also appears to be stabilized by interaction with the tRNATyr. Binding of the substrate tyrosine results in subtle and cooperative movements of the side chains within the tyrosine‐binding pocket. In the OMeTyr‐specific mutant synthetase structure, the signature motif KMSKS loop and acceptor stem‐binding loop 133–143 were surprisingly ordered in the absence of bound ATP and tRNA. The active‐site mutations result in altered hydrogen bonding and steric interactions which favor binding of OMeTyr over l‐tyrosine. The structure of the mutant and wild‐type TyrRS now provide a basis for generating new active‐site libraries to evolve synthetases specific for other unnatural amino acids.
Three‐dimensional structure of (1,4)‐β‐d‐mannan mannanohydrolase from tomato fruit
Authors: Bourgault Richard , Oakley Aaron J. , Bewley J. Derek , Wilce Matthew C.J. 
Published: April 2005

AbstractThe three‐dimensional crystal structure of tomato (Lycopersicon esculentum) β‐mannanase 4a (LeMAN4a) has been determined to 1.5 Å resolution. The enzyme adopts the (β/α)8 fold common to the members of glycohydrolase family GH5. The structure is comparable with those of the homologous Trichoderma reesei and Thermomonospora fusca β‐mannanases: There is a conserved three‐stranded β‐sheet located near the N terminus that stacks against the central β‐barrel at the end opposite the active site. Three noncanonical β‐helices surround the active site. Similar helices are found in T. reesei but not T. fusca β‐mannanase. By analogy with other β‐mannanases, the catalytic acid/base residue is E204 and the nucleophile residue is E318. The active site cleft of L. esculentum β‐mannanase most closely resembles that of the T. reesei isozyme. A model of substrate binding in LeMAN4a is proposed in which the mannosyl residue occupying the −1 subsite of the enzyme adopts the 1S5 skew‐boat conformation.
Lack of effect of moderate hepatic impairment on the pharmacokinetics of oral oseltamivir and its metabolite oseltamivir carboxylate
Authors: Snell Paul , Dave Nisha , Wilson Katie , Rowell Lucy , Weil Angelica , Galitz Lawrence , Robson Richard 
Published: April 2005

AimsTo compare the pharmacokinetics of oseltamivir and oseltamivir carboxylate in hepatically impaired patients and healthy subjects.MethodsHepatically impaired patients (n = 11) and healthy subjects (n = 11) were individually paired on the basis of gender, age (±10 years) and body weight (±20%) and administered a single dose of oseltamivir (75 mg).ResultsOseltamivir and oseltamivir carboxylate Cmax were ≤6% and ≤19% lower, and their AUC(0,∞) 33% higher and ≤19% lower, respectively, in hepatically impaired patients compared with healthy subjects. These changes are within the safety limits for the drug.ConclusionsThe metabolism of oseltamivir is not compromised minimally in hepatically impaired patients. No dose adjustment is required in these patients when receiving oseltamivir.
Persistence and determinants of statin therapy among middle‐aged patients for primary and secondary prevention
Authors: Perreault S. , Blais L. , Lamarre D. , Dragomir A. , Berbiche D. , Lalonde L. , Laurier C. , St‐Maurice F. , Collin J. 
Published: April 2005

AimsStatins have been shown to significantly reduce morbidity and mortality in patients with coronary artery disease (CAD), and also in patients with dyslipidaemia when statins are taken regularly. Middle‐aged patients have the highest level of forecasting benefit and little is known about persistence rate of these therapies in a real‐life setting. The objective was to evaluate the persistence rate of middle‐aged patients initiating a statin therapy and its relation with several determinants for primary and secondary prevention.MethodsA cohort was reconstructed using the RAMQ databases. All patients aged 50–64 years‐old who received at least one statin prescription between 1 January, 1998 and 31 December, 2000 for a new intention of treatment for dyslipidaemia were included in the cohort and followed up until 30 June, 2001. The date of the first prescription of statin was defined as the index date. There were 4316 patients in the secondary prevention (CAD diagnosis) and 13 642 patients in primary prevention cohort. The cumulative persistence rate was estimated using Kaplan‐Meier, and Cox regression models were used to estimate the hazard ratio of ceasing statins.ResultsWe found that persistence with statins had fallen to 71% after 6 months of treatment, and had declined to 45% after 3 years in the secondary prevention cohort; the corresponding figures were 65% and 35% in the primary prevention cohort. Our results suggest that patients with dyslipidaemia in primary prevention compared with those in secondary prevention (HR: 1.18; 1.11–1.25) are less likely to be persistent. Patients with other cardiovascular risk factors such as age (HR: 0.99; 0.98–0.99), diabetes (HR: 0.84; 0.79–0.90), hypertension (HR: 0.76; 0.72–0.80) were most likely to be persistent with statins. We observed lower persistence in patients who have used the greatest number of pharmacies and prescribing physicians.ConclusionThis analysis indicates that barriers to persistence occur early in the therapeutic course. Overall persistence with statins is low, and particularly among patients with few other cardiovascular risk factors.
Is INR between 2.0 and 3.0 the optimal level for Chinese patients on warfarin therapy for moderate‐intensity anticoagulation?
Authors: You J. H. S. , Chan F. W. H. , Wong R. S. M. , Cheng G. 
Published: April 2005

AimTo examine the optimal range of International Normalized Ratio (INR) for Chinese patients receiving warfarin for moderate‐intensity anticoagulation.MethodsThis was a retrospective cohort study conducted at the ambulatory setting of a 1400‐bed public teaching hospital in Hong Kong. The INR measurements and occurrence of serious or life‐threatening haemorrhagic and thromboembolic events among patients newly started on warfarin from 1 January 1999 to 30 June 2001 for indications with target INR 2–3 were analysed. The INR‐specific incidence of bleeding and thromboembolism were calculated.ResultsA total of 491 patients were included, contributing to 453 patient‐years of observation period. Forty‐seven of the 491 patients experienced 25 haemorrhagic events (5.5 per 100 patient‐years) and 27 thromboembolic events (6.0 per 100 patient‐years). The percentage of patient‐time spent within therapeutic INR range (2–3), INR <2 and INR >3 were 50, 44 and 6%, respectively. The incidence of either haemorrhagic or thromboembolic events was lowest (≤4 events per 100 patient‐years) at INR values between 1.8 and 2.4.ConclusionsAn INR of 1.8–2.4 appeared to be associated with the lowest incidence rate of major bleeding or thromboembolic events in a cohort of Hong Kong Chinese patients receiving warfarin therapy for moderate‐intensity anticoagulation.
Spironolactone reduces brachial pulse wave velocity and PIIINP levels in hypertensive diabetic patients
Authors: Davies J. , Gavin A. , Band M. , Morris A. , Struthers A. 
Published: April 2005

AimsTo assess whether spironolactone has beneficial effects on blood pressure (BP), N‐terminal propeptide of type III procollagen (PIIINP) and pulse wave velocity (PWV) in hypertensive, type II diabetics.MethodsTen patients with type II diabetes and hypertension were enrolled in a randomized, double‐blind crossover study comparing 4 months’ treatment with spironolactone and placebo with a 4‐week washout phase. BP, PIIINP and carotid‐radial PWV were measured at the end of each treatment phase.ResultsCompared with placebo, spironolactone reduced systolic BP by 15.6 ± 46.1 mmHg (P = 0.005, 95% CI 2.7–28.5 mmHg), PIIINP by 0.6 ± 0.3 µg l−1 (P = 0.04, 95% CI 0.02–1.1 µg l−1) and PWV by 0.6 ± 0.2 m s−1 (P = 0.008, 95% CI 0.18–1.02 m s−1).ConclusionsSpironolactone is effective at reducing systolic BP and brachial artery stiffness as indicated by PWV. It also reduces PIIINP in type II diabetic patients with hypertension.