bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of acrylic–polyurethane hybrid emulsions synthesized by the semibatch emulsion copolymerization of acrylates using different polyurethane particles
Authors: Šebenik Urška , Krajnc Matjaž 
Published: July 2005

AbstractAqueous acrylic–polyurethane hybrid emulsions were prepared by the semibatch emulsion copolymerization of methyl methacrylate and butyl acrylate in the presence of eight polyurethane dispersions. The polyurethane dispersions were synthesized with isophorone diisocyanate, 1000 and 2000 molecular weight polyester polyols, 1000 molecular weight polyether polyol, butanediol, and dimethylol propionic acid. Acrylic monomers were added in the monomer emulsion feed. We studied the effect of the use of different polyurethane seed particles and the effect of different weight ratios of methyl methacrylate to butyl acrylate on the emulsion properties, microphase structure, and mechanical properties of hybrid films. The average particle size and distribution were determined by photon correlation spectroscopy. The rheological properties of polyurethane dispersions and hybrid emulsions were tested under destructive conditions by an examination of flow curves and under nondestructive conditions of oscillatory shear in a range of linear viscoelastic responses. Differential scanning calorimetry was performed to characterize the thermal‐response properties of polymeric films. The relative average molecular weights were determined by gel permeation chromatography. The interactions between the acrylic and polyurethane components in hybrid particles and particle structure were studied with infrared spectroscopy and nuclear magnetic resonance spectroscopy. Mechanical properties such as the Koenig hardness, tensile strength, elongation at break, and Young's modulus were measured. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4050–4069, 2005
Exciton‐polaritons and nanoscale cavities in photonic crystal slabs
Authors: Andreani Lucio Claudio , Gerace Dario , Agio Mario 
Published: July 2005

AbstractRecent theoretical work on exciton–light coupling in waveguide‐embedded photonic crystals is reviewed. After a short description of the theory of photonic crystal slabs, the following issues are discussed: (i) a quantum‐mechanical formulation of the interaction between photonic modes and quantum‐well excitons, leading to a description of photonic crystal polaritons; (ii) calculations of variable‐angle reflectance spectra, which show that radiative polaritons can be excited by an optical beam incident on the slab surface; (iii) a description of nanoscale cavities with extremely high Q‐factors and low mode volumes in photonic crystal slabs; (iv) a quantum‐mechanical model of the interaction between confined nanocavity modes and single quantum‐dot transitions, leading again to a strong‐coupling regime of light–matter interaction. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ion/molecule reactions in the orifice‐skimmer region of an atmospheric pressure Penning ionization mass spectrometer
Authors: Furuya Hiroko , Fujimaki Susumu , Kambara Shizuka , Suzuki Shigeo , Hashimoto Yutaka , Okazaki Shigemitsu , Wada Akira , Beech Iwona B. , Sunner Jan , Hiraoka Kenzo 
Published: July 2005

AbstractAtmospheric pressure Penning ionization mass spectra of methanol were measured as functions of Ar or He gas pressure in the first vacuum chamber, the position of the skimmer, and the voltage applied between the orifice and the skimmer. When the orifice and the skimmer were coaxial with a distance of 4 mm, the distribution of CH3OH(CH3OH)n clusters was only weakly dependent on both Ar pressure (in the range of 19–220 Pa) and orifice‐skimmer voltage (in the range of 1–45 V). The ion/molecule reaction CH3OH + CH3OH → CH(CH3OH) + H2O was observed in the free jet expansion, especially at high orifice‐skimmer voltage values. When the orifice and the skimmer were off‐centered and the distance between them was increased to 18 mm, the formation of large CH3OH(CH3OH)n clusters, as well as their dissociation, were seen. The endothermic proton transfer reaction, CH(CH3OH) + CH3OH → CH3OH + CH3OCH3, occurred at high orifice‐skimmer voltage. The collision‐induced dissociation of cluster ions by He gas in the first vacuum chamber was much more efficient than by Ar. These results demonstrated that the mass spectra are highly dependent on skimmer position and on orifice‐skimmer voltage and that ions observed by mass spectrometry do not necessarily reflect the abundance of ions produced in the atmospheric pressure ion source. Copyright © 2005 John Wiley & Sons, Ltd.
Effects of antiarrhythmic drug therapy on atrioventricular nodal function during atrial fibrillation in humans*
Authors: Mangin Laurence , Vinet Alain , Pagé Pierre , Glass Leon 
Published: July 2005

Abstract

Aims
To assess the effects of metoprolol and amiodarone on atrial and ventricular activity during atrial fibrillation (AF) in post-surgical patients, and to develop and use a mathematical model of the atrioventricular (AV) node during AF that incorporates parameters describing the properties of the AV node to evaluate the physiological basis of the drug effects.

Methods and results
Ten post-surgical patients were evaluated where three received no medical therapy, three received metoprolol, three received amiodarone, and one received both metoprolol and amiodarone. The medications led to increases of 37–310 ms in the mean VV interval in treated patients, but much smaller changes in the mean AA intervals in the right and left atria. The mathematical model incorporating a random influence of the concealed conduction parameter was capable of reproducing the histograms of the VV intervals based on the input from the right atrium by systematically searching parameter space.

Conclusions
Changes in the ventricular rate are mainly due to the alteration in the AV nodal properties rather than changes in the atrial rhythm. The medications can display differential effects on the physiological properties of the AV node, and therefore the mathematical model may help to identify novel pharmacological targets.
Wavelength and vulnerability to atrial fibrillation: Insights from a computer model of human atria
Authors: Jacquemet Vincent , Virag Nathalie , Kappenberger Lukas 
Published: July 2005

Abstract

Aim
To explain the contradictory results related to the concept of critical cardiac wavelength in the initiation and perpetuation of atrial fibrillation (AF).

Methods
A biophysically based computer model was used to: (1) study the relationship between wavelength and AF perpetuation in the presence of multiple re-entrant wavelets, (2) evaluate the performance of different existing methods for wavelength estimation in the presence of different arrhythmogenic substrates, and (3) document the impact of either heterogeneities in refractoriness or the presence of a mother rotor on wavelength estimation.

Results
The simulations confirmed that the wavelength must be below a critical value for AF to be sustained, when the perpetuation mechanism relies on multiple re-entrant wavelets. The estimated value of wavelength was not the same for all methods tested and depended in part on the nature of the spatio-temporal organization of the AF dynamics.

Conclusion
A priori information about the underlying wavelet dynamics is needed for a correct interpretation of the cardiac wavelength as estimated by the current clinical methods.
Antitumor and antimetastatic actions of eicosapentaenoic acid ethylester and its by‐products formed during accelerated stability testing
Authors: Kimura Yoshiyuki , Sumiyoshi Maho 
Published: July 2005

The aim of the present work was to compare the effects of eicosapentaenoic acid (EPA) ethylester and EPA derivatives (EPAD) on tumor growth and metastasis to the lung in tumor‐bearing mice. Because EPA is very unstable during long‐term storage, the EPAD were subjected to accelerated testing under storage conditions of 60 ± 5% relative humidity at 37°C for 30 days. EPAD are composed of a mixture of a newly identified EPA ethylester dimer and EPA hydroxyethylester, and known EPA and EPA ethylesters. The inhibitory effects of EPAD, the EPA ethylester dimer and EPA hydroxyethylester on Matrigel‐induced capillary‐like network formation were stronger than the effect of EPA ethylester. The oral administration of EPAD (300 or 1000 mg/kg) inhibited angiogenesis in gels containing Matrigel supplemented with vascular endothelial growth factor (VEGF) and heparin in an in vivo model, but EPA ethylester had no effect. EPA ethylester (300 or 1000 mg/kg) or EPAD (1000 mg/kg) inhibited tumor growth in mice with subcutaneously implanted LLC. Furthermore, EPAD inhibited metastasis to the lung in mice implanted with LLC subcutaneously, but EPA had no effect. EPAD increased the CD8+ T‐cell population in the spleen compared with mice with subcutaneously implanted LLC. EPA ethylester increased the natural killer cell population in the spleen. Thus, it is suggested that the mechanisms of the antitumor and/or antimetastatic actions of EPAD and EPA ethylester involve different immune functions, and that the EPA ethylester dimer and the EPA hydroxyethylester of EPAD may contribute to these actions. (Cancer Sci 2005; 96: 441–450)
Lamivudine therapy in chronic delta hepatitis: a multicentre randomized‐controlled pilot study
Authors: NIRO G. A. , CIANCIO A. , TILLMAN H. L. , LAGGET M. , OLIVERO A. , PERRI F. , FONTANA R. , LITTLE N. , CAMPBELL F. , SMEDILE A. , MANNS M. P. , ANDRIULLI A. , RIZZETTO M. 
Published: July 2005

SummaryBackground:  Delta virus (HDV)‐related chronic hepatitis is difficult to treat.Aims:  To evaluate the efficacy of lamivudine 100 mg daily on serum HDV‐RNA, hepatitis D virus antibodies and alanine aminotransferase levels, liver histology, and on hepatitis B surface antigen seroconversion.Methods:  Thirty‐one hepatitis B surface antigen‐positive, HDV‐RNA‐positive patients with ALT ≥ 1.5 upper normal level and compensated liver disease were randomized (1:2 ratio) to placebo (group A, n = 11) or lamivudine (group B, n = 20) for 52 weeks; thereafter, all patients were given lamivudine for 52 weeks and followed up for 16 weeks.Results:  Twenty‐five patients (81%) completed the study. No patient was HDV‐RNA‐negative at week 52; three patients (11%) were negative at week 104. Two of them remained HDV‐RNA‐negative at week 120, and one lost the hepatitis B surface antigen without seroconversion. Paired pre‐treatment and week 104 liver biopsies were available from 19 patients: of which three of seven (43%) from group A and two of 12 patients (17%) from group B had a ≥2 point decrease in the Ishak necroinflammatory score.Conclusion:  A sustained complete response was achieved in 8% of hepatitis D virus‐infected patients treated with lamivudine and a partial histological response in 26% of them. Hepatitis D virus viraemia was unaffected, even in patients when hepatitis B virus replication was lowered by lamivudine therapy.
Trends in the management and survival of digestive tract cancers among patients aged over 80 years
Authors: BOUVIER A. M. , LAUNOY G. , LEPAGE C. , FAIVRE J. 
Published: July 2005

SummaryBackground:  Advances have occurred in the management of digestive tract cancers, but it is not known how much they have benefited the elderly.Aims:  To determine trends in treatment, stage at diagnosis and prognosis of digestive tract cancers among patients aged ≥80 years in two well‐defined French populations.Design:  Time trends were studied in three age classes and in 5 four‐year time intervals. A multivariate relative survival analysis was performed to estimate the independent effect of both age and period on prognosis.Results:  Five‐year relative survival rates were 1.9% for oesophageal cancer, 12% for stomach cancer, 41% for colon cancer and 37% for rectal cancer. The survival rates improved between the first and the fifth period for all cancer sites except for oesophageal cancer. This improvement remained significant after adjustment for age, sex, site and treatment. It was associated with an increase in the proportion of patients who underwent curative resection. Very few patients received adjuvant chemotherapy. The use of adjuvant radiotherapy for rectal and oesophageal cancers did not significantly increase over time.Conclusions:  Except for oesophageal cancers, substantial advances in the care of digestive tract cancers in the elderly have been achieved. Surgery should not be restricted on the basis of age alone. Further improvements can be made in particular to enhance adjuvant therapy whenever possible.
Review article: gastro‐oesophageal reflux disease – the extent of the problem
Authors: MOAYYEDI P. , AXON A. T. R. 
Published: July 2005

SummaryThere have been little review data on the period prevalence of heartburn symptoms in the community. We analysed reflux symptom data from a test‐and‐treat trial that evaluated community Helicobacter pylori levels and added these to data identified from a literature search. We found 31 papers reporting on 77 671 subjects who provided information on the frequency of heartburn symptoms in the community. Pooled data from these papers suggested that, in Western populations, 25% had symptoms at least once per month, 12% had symptoms at least weekly and 5% had heartburn daily. Reflux symptoms were less common in East Asian populations with only 7% having heartburn at least once per month. Heartburn is a significant problem in Western societies.
Review article: gastro‐oesophageal reflux disease – the health economic implications
Authors: MASON J. , HUNGIN A. P. S. 
Published: July 2005

SummaryFor the vast majority of patients with gastro‐oesophageal reflux disease appropriate care involves the management of symptoms with lifestyle advice and drugs. However, there is dissension about the appropriate use of endoscopy, whether drugs should be stepped up or down according to potency, how long drugs should be used for, the role of lifestyle advice, and, related to this, the role of patients’ lifestyle choices.This exploration of the economics of gastro‐oesophageal reflux disease reviews its cost burden to the UK, assesses published economic models for their strengths and weaknesses and examines current recommendations for gastro‐oesophageal reflux disease management from a socioeconomic perspective. Drugs prescribed predominantly for dyspepsia cost the UK National Health Service a projected £625 million in 2004, 7% of the primary care prescribing budget. When general practitioners consultations, endoscopies, over‐the‐counter sales and sickness absences are included the UK cost rises to £1.5 billion: approximately half of this cost can be ascribed to gastro‐oesophageal reflux disease. Emphasis upon regular review and stepping down treatment (while maintaining adequate symptom relief) is both clinically appropriate and resource efficient. Other cost‐effectiveness issues largely lack objective answers because investment in treatment for gastro‐oesophageal reflux disease depends upon how much more, at the margin, society wishes to invest for further but diminishing symptom relief.
Review article: Helicobacter pylori and gastro‐oesophageal reflux disease
Authors: DELANEY B. , McCOLL K. 
Published: July 2005

SummaryEpidemiological studies demonstrate a negative association between Helicobacter pylori infection and gastro‐oesophageal reflux disease and its complications. This might represent a protective effect because of the tendency for H. pylori infection to lower gastric acid secretion with advancing age. However, studies of the effect of H. pylori eradication on gastro‐oesophageal reflux disease have failed to show any worsening of gastro‐oesophageal reflux disease symptoms. Several interactions between H. pylori and proton‐pump inhibitor therapy used to treat gastro‐oesophageal reflux disease need to be considered. Helicobacter pylori infection improves the control of gastric acidity by proton‐pump inhibitors and this produces a small advantage in clinical control of reflux disease. The infection prevents rebound acid hypersecretion occurring when proton‐pump inhibitor therapy is discontinued. However, concerns have been expressed that the body gastritis induced by proton‐pump inhibitor therapy in H. pylori‐infected subjects might increase the risk of gastric cancer. At present, it is unclear whether H. pylori should be eradicated in gastro‐oesophageal reflux disease patients.
Review article: quality‐of‐life issues in gastro‐oesophageal reflux disease
Authors: QUIGLEY E. M. M. , HUNGIN A. P. S. 
Published: July 2005

SummaryThe purpose of this review is to explore issues relating to quality of life in gastro‐oesophageal reflux disease, examining the range of generic and disease‐specific instruments available, their applicability and limitations and to overview the effect of gastro‐oesophageal reflux disease on quality of life. Whereas instruments have been developed to assist researchers, there is a paucity of reliable instruments for pragmatic use in the clinical setting. The situation is complicated because there is not necessarily a direct correlation between endoscopic findings and symptom severity and non‐erosive reflux disease is now recognized as an important manifestation of gastro‐oesophageal reflux disease. However, quality‐of‐life instruments are useful in evaluating the impact of therapies and interventions, although these are limited, particularly in surgical interventions. Impaired quality of life now forms part of a definition of gastro‐oesophageal reflux disease, the impact of which goes beyond the symptoms alone. While the symptoms themselves have a negative effect on sufferers’ lives, there are secondary effects caused by impaired physical, emotional and social functioning on productivity. Non‐gastrointestinal problems caused by gastro‐oesophageal reflux disease also impair quality of life. There is an ongoing need to develop instruments which truly measure the impact of gastro‐oesophageal reflux disease and which are readily interpretable to the individual patient and clinician.
Review article: role of pepsin and bile in gastro‐oesophageal reflux disease
Authors: TACK J. 
Published: July 2005

SummaryGastro‐oesophageal reflux disease is defined as the presence of symptoms or lesions that can be attributed to the reflux of gastric contents into the oesophagus. Aspiration and prolonged monitoring studies in humans have shown that reflux of gastric contents is comprised of both acid and non‐acid components, in healthy as well as diseased people. Methods to monitor the non‐acid component of the refluxate are described in detail. Experimental models suggest that synergism between acid and pepsin and conjugated bile acids have the greatest damaging potential for oesophageal mucosa, although unconjugated bile acids may be caustic at a more neutral pH. Human studies are compatible with a synergistic action between acid and duodenogastric reflux in inducing lesions. During prolonged monitoring studies, typical gastro‐oesophageal reflux disease symptoms are more related to acid reflux events than to non‐acid reflux events. However, symptoms that persist during acid‐suppressive therapy are often related to non‐acid reflux events. The therapeutic options for the non‐acid component of the refluxate, including acid suppression, prokinetics, baclofen and surgery, are discussed.
Review: What do we mean by GERD? – definition and diagnosis
Authors: JONES R. , GALMICHE J. P. 
Published: July 2005

SummaryGastro‐oesophageal reflux disease (GERD) is a condition in which the gastro‐oesophageal reflux provokes symptoms or complications. Since the majority of patients with heartburn do not have mucosal breaks, expressions such as ‘endoscopy‐negative reflux disease’ (ENRD), ‘non‐erosive reflux disease’ (NERD), or even ‘reflux‐like dyspepsia’ and ‘functional heartburn’ are frequently employed despite the lack of consensus concerning their exact meaning. Moreover, definition of a disease does not mean that precise diagnostic criteria exist. Diagnostic approaches to GERD differ considerably between primary and secondary care. The primary care physician's role is to decide, on the basis of symptoms and clinical examination, if it is likely that the patient has some serious problem which requires urgent investigation and intervention. In practice, a symptom‐based diagnosis can often be made reliably because heartburn and regurgitation are very specific for GERD. The secondary care physician has to make a full evaluation of an already highly‐selected patient and, as far as possible, to make a comprehensive, accurate diagnosis, using whatever investigative tools are required. However, there is no ‘gold standard’ for the diagnosis of GERD and 24‐hour pH monitoring lacks sensitivity in NERD. Recently, impedance‐pH monitoring has been introduced and promising results have been reported. However, this new technology needs further validation and technical improvement before being employed in routine clinical investigation.
Review article: the long‐term use of proton‐pump inhibitors
Authors: RAGHUNATH A. S. , O'MORAIN C. , MCLOUGHLIN R. C. 
Published: July 2005

SummaryMore than 15 years after the launch of omeprazole in 1988, proton‐pump inhibitors remain central to the management of acid‐suppression disorders and are unchallenged with regard to their efficacy and popularity among doctors and patients. They are considered safe despite early concerns about the possibility of an association with cancer and gastric atrophy; current concerns about long‐term proton‐pump inhibitor therapy are centred mainly on a possible association with fundic gland polyps and between Helicobacter pylori and gastric atrophic changes. Long‐term proton‐pump inhibitor usage accounts for the majority of the total proton‐pump inhibitor usage. Long‐term usage is difficult to define and most patients take proton‐pump inhibitors non‐continuously. Data indicate that a substantial proportion of long‐term users do not have a clear indication for their therapy and there is thus room for reduction or rationalization of treatment. Overall, on‐demand therapy is more cost‐effective than continuous therapy and should be considered wherever possible.
Review article: how valuable are proton‐pump inhibitors in establishing a diagnosis of gastro‐oesophageal reflux disease?
Authors: VAKIL N. 
Published: July 2005

SummaryDiagnostic studies for gastro‐oesophageal reflux disease (endoscopy, pH testing) have significant limitations. A short trial of acid suppression with a proton‐pump inhibitor is often used in clinical practice as a diagnostic test for gastro‐oesophageal reflux disease. If there is a significant improvement in symptoms, the patient is considered to have gastro‐oesophageal reflux disease. Several studies have evaluated the administration of proton‐pump inhibitors as a diagnostic test for gastro‐oesophageal reflux disease. A recent meta‐analysis found that response to a proton‐pump inhibitor had limited value as a diagnostic test. Likelihood ratios for a positive test ranged from 0.45 to 1.86. The positive predictive value of the test ranged from 0.17 to 0.90 and the negative predictive value from 0.17 to 1, depending on the gold standard against which comparisons were made. These results may be explained by the inadequacy of the gold standard against which the proton‐pump inhibitor test is compared or by the inability of acid suppression to differentiate between gastro‐oesophageal reflux disease, peptic ulcer disease or dyspepsia. Although a trial of acid suppression may have pragmatic value in clinical practice, the proton‐pump inhibitor test is not an accurate test for the diagnosis of gastro‐oesophageal reflux disease.