bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron and hole-related luminescence processes in gate injection transistors
Authors: Meneghini M. , Scamperle M. , Pavesi M. , Manfredi M. , Ueda T. , Ishida H. , Tanaka T. , Ueda D. , Meneghesso G. , Zanoni E.
Published: July 2010

This paper reports an extensive investigation of the luminescence processes in GaN-based gate injection transistors (GITs). The results of the analysis indicate that: (i) GITs operating in on-state conditions can emit a weak luminescence signal; (ii) for moderate gate voltage levels, luminescence is originated at the edge of the gate toward the drain side, due to hot electrons accelerated by the high gate-drain electric field; (iii) for higher gate voltage levels, luminescence is originated in the region between the gate and the source of the devices, due to the recombination of the holes injected from the gate and the electrons present in the channel. Results obtained by means of electrical and optical measurements are compared throughout the paper to support the interpretation of the measurement results.
Band alignment at Cu2O/La0.7Sr0.3MnO3 interface: A combined experimental-theoretical determination
Authors: Cantoni M. , Petti D. , Bertacco R. , Pallecchi I. , Marré D. , Colizzi G. , Filippetti A. , Fiorentini V.
Published: July 2010

Cu 2 O / La 0.7 Sr 0.3 MnO 3 is a promising heterostructure for the realization of all-oxide spintronics devices, with La0.7Sr0.3MnO3 (LSMO) and Cu2O playing the roles of ferromagnet and semiconductor, respectively. Here we use x-ray photoelectron spectroscopy and first principles calculations to determine the valence band offset at the Cu2O/LSMO interface. The interface band alignment is typical of a p-type semiconductor/metal contact, with an interface barrier of 0.3–0.5 eV depending on Cu2O thickness. The calculated energetics indicates that the prevailing interface is between SrO-terminated LSMO and Cu planes of Cu2O.
Method to calculate electric fields at very small tip-sample distances in atomic force microscopy
Authors: Sacha G. M.
Published: July 2010

A method to calculate electric magnitudes at very small tip-sample distances in atomic force microscopy is presented. We show that the method accurately calculates the electrostatic potential and vertical force for electrostatic force microscopy geometries that cannot be correctly simulated by the standard techniques. This technique can accurately calculate tip-sample distances four orders of magnitude smaller than the tip radius. We also demonstrate that, at this range, traditional techniques underestimate the electrostatic force in almost 30%. Finally, we calculate the jump-to-contact distance for geometries obtained from experiments that combine atomic force microscopy and scanning tunneling microscopy.
The Sustainable Rivers Audit: assessing river ecosystem health in the Murray - Darling Basin, Australia
Authors: Davies P. E. , Harris J. H. , Hillman T. J. , Walker K. F.
Published: July 2010

The Sustainable Rivers Audit (SRA) is a systematic assessment of the health of river ecosystems in the Murray–Darling Basin (MDB), Australia. It has similarities to the United States’ Environmental Monitoring and Assessment Program, the European Water Framework Directive and the South African River Health Program, but is designed expressly to represent functional and structural links between ecosystem components, biophysical condition and human interventions in the MDB. Environmental metrics derived from field samples and/or modelling are combined as indicators of condition in five themes (Hydrology, Fish, Macroinvertebrates, Vegetation and Physical Form). Condition indicator ratings are combined using expert-system rules to indicate ecosystem health, underpinned by conceptual models. Reference condition, an estimate of condition had there been no significant human intervention in the landscape, provides a benchmark for comparisons. To illustrate, a synopsis is included of health assessments in 2004–2007. This first audit completed assessments of condition and ecosystem health at the valley scale and in altitudinal zones, and future reports will include trend assessments. SRA river-health assessments are expected to play a key role in future water and catchment management through integration in a Basin Plan being developed by the Murray–Darling Basin Authority for implementation after 2011. For example, there could be links to facilitate monitoring against environmental targets.
Integrating aquatic science and policy for improved water management in Australia
Authors: Tomlinson Moya , Davis Richard
Published: July 2010

Worldwide, science–policy integration across jurisdictional boundaries is emerging as a major challenge to sustainable water management. The Australian national water reforms require statutory provision for environmental outcomes in water plans, informed by the best available science. Assessments of progress towards this goal of scientifically rigorous environmental water provision indicate that, despite a multiplicity of effort in aquatic research and management, the pace of reform has been too slow for adequate protection of aquatic ecosystems. Although there are significant knowledge gaps, these are not the only obstacles to effective application of aquatic science in water plans. Progress on environmental water reform can be enhanced by recognising the cultural differences between science and policy, and by integrating communication and policy development activities from the outset of every applied science research program. Cross-jurisdictional progress in sustainable water management requires a comprehensive water research and policy development strategy using a toolbox of techniques to harness the considerable expertise and knowledge of aquatic scientists, policy makers and water planners in an integrated program to deliver the aquatic science applications called for by the national water reforms.
Patient participation within a globalised patient population
Authors: Kang M. Agnes , Zayts Olga
Published: July 2010

Data from multicultural contexts add more complexity to many findings regarding healthcare practices that have been reported in the literature. For example, patient participation has been reported to contribute to the enhancement of healthcare results (e.g. Candlin, 2006; Thompson, 2008). However, patient participation may be problematic when participants in the medical encounter face sociocultural and linguistic barriers. In this paper we focus on interactional difficulties that non-native speakers of English encounter in prenatal genetic counseling sessions. These difficulties, we argue, may place limitations on the extent of patient participation, when patient participation is narrowly defined in terms of verbal contributions. The data for the study come from a prenatal genetic counseling clinic in Hong Kong, and the participants of the interactions originate from various countries in the Asia region. Using a conversation analytic approach, we examine interactional difficulties in an attempt to capture the specific challenges faced by healthcare providers and patients in an increasingly diverse healthcare context. We also argue for an ethnographic perspective to examine patient participation in the multilingual context and to highlight dimensions of second language use and cultural diversities as observable evidence of patient participation.
‘Reassuring’ during clinical examinations
Authors: Bridges S. , McGrath C. , Yiu C.K.Y. , Cheng B.S.S.
Published: July 2010

Novices and experts alike must engage in the interactional complexities of clinical consultations as a form of institutional talk. This includes reconciling the demands of task completion with those of effective patient communication in order to achieve successful outcomes. This paper reports a study that identifies ‘giving reassurance’ as an area of relative communicative weakness for undergraduate student dentists (novices) and examines the mechanisms by which an experienced dentist (expert) interactionally accomplishes ‘reassurance’ during a single consultation in a multilingual Asian dental education clinic. Two stages of data gathering and analysis were adopted within a multivariate framework (Heritage and Maynard, 2006). First, 51 student dentists were rated using a 360° approach during a single clinical consultation. Interactants and observers rated each student’s communicative performance using an established scale in dentistry (Theaker, Kay, and Gill, 2000). Descriptive statistical analysis identified areas of relatively lower communication performance with ‘giving reassurance’ during the ‘examination’ stage consistently rated as the least accomplished skill. Second, an experienced dentists’ consultation was audio recorded and transcribed. Using conversational analysis (CA) as the method of analysis, strategies are identified in the process of an experienced dentist and a patient co-constructing ‘reassurance’ as a two-way process.
Representations of Islam in British broadsheet and tabloid newspapers 1999–2005
Authors: Baker Paul
Published: July 2010

This paper describes the analysis of an 87 million word corpus of British newspaper articles which refer to the subject of Islam. In order to examine representations of Islam and Muslims, the corpus was subjected to a comparative analysis, by analysing the lexis that was used most significantly in the tabloid articles, when compared to the broadsheets, and vice versa. Concordances were then analysed in order to investigate the data in a more qualitative way. It was found that the tabloids tended to focus more on British interests, writing about Muslims in a highly emotional style, in connection with terrorist attacks and religious extremism, focussing on a small number of high-profile Muslim “villains”. On the other hand, the broadsheets had a more restrained reporting stance, writing about Muslims in a wider range of contexts, although their focus on world news resulted in them covering more stories about Muslims engaged in wars. The paper raises issues regarding the meaning of bias, and the process by which readers internalise lexical associations and the extent to which such associations impact on attitudes
Doing a Doc! – The thoughts, experiences and relationships of students undertaking a Professional Doctorate in Counselling
Authors: Silvester Anita
Published: July 2010

Aim: To explore the experiences of students undertaking a Professional Doctorate in Counselling. Method: The participants, students from years 1–6 on a Professional Doctorate programme within a UK university, were interviewed and the transcripts analysed using a thematic analysis approach. Themes identified include Personal Development, Expectations, Passion and Voice. However there is an overarching theme for these students' experiences of a ‘therapeutic edge’, which appears specific to them. Discussion: It seems clear that students undertaking this course of study will be challenged in a number of ways, as is also evidenced in the literature available. Conclusion: Students embarking on a Professional Doctorate in Counselling course may benefit from an understanding of the potential challenges they could face apart from the academic ones they perhaps anticipate. Such awareness might encourage them to identify good support systems to access throughout their studies.
Genetic Dissection of Basal Resistance to Pseudomonas syringae pv. phaseolicola in Accessions of Arabidopsis
Authors: Forsyth Alec , Mansfield John W. , Grabov Nina , de Torres Marta , Sinapidou Eva , Grant Murray R.
Published: July 2010

We have examined the genetics of nonhost resistance in Arabidopsis, using the bean pathogen Pseudomonas syringae pv. phaseolicola race 6 1448A to probe accessions for natural variation in basal defense. Symptoms rarely developed in leaves of Niedersenz (Nd), some yellowing and occasional necrosis developed in Columbia (Col), whereas tissue collapse was observed in Wassilewskija (Ws) after inoculation by infiltration. Analysis of F2 progeny and recombinant inbred lines (RIL) from a cross between Col and Nd revealed a pattern of continuous symptom increase, indicating the operation of quantitative determinants of resistance. By mapping quantitative trait loci (QTL), significant linkage was determined for resistance (low symptom score) to markers on chromosome 4. Segregation in the F2 cross from Nd × Ws indicated the operation of two dominant genes for resistance, one of which was FLS2 encoding the flagellin receptor. The requirement for FLS2 to confer resistance was confirmed by transgenic experiments, and we showed that the response to P. syringae pv. phaseolicola was affected by FLS2 gene dosage. Using RIL, the second locus was mapped as a QTL to a large interval on chromosome 1. Both FLS2 and the QTL on chromosome 1 were required for the highest level of resistance to bacterial colonization and symptom development in Nd.
Antibiotic resistance in invasive Streptococcus pneumoniae isolates identified in Scotland between 1999 and 2007
Authors: Cooke Benjamin , Smith Andrew , Diggle Mathew , Lamb Karen , Robertson Christopher , Inverarity Donald , Jefferies Johanna , Edwards Giles , Mitchell Timothy , Clarke Stuart , McMenamin Jim
Published: July 2010

Data from 4727 invasive isolates of Streptococcus pneumoniae submitted to the Scottish Haemophilus, Legionella, Meningococcus and Pneumococcus Reference Laboratory between 1999 and 2007 were analysed to establish susceptibility profiles to penicillin, erythromycin and cefotaxime. Pneumococcal resistance to penicillin over the study period remained low, with only 0.2 % (n=7/4727) of isolates falling into this category (MIC ≥2 mg l−1). These isolates have been sporadic, and have mainly represented serogroup 14 (ST9) and 9 (ST156). In comparison, the ‘intermediate sensitivity’ group (MIC 0.12–1 mg l−1) ranged between 2 and 6 % per year, the majority from serogroup 9 (ST156). Over the study period, we found that 12 % (n=585/4727) of isolates were erythromycin-resistant (MIC >0.5 mg l−1), with the majority (n=467; 80 %) of these isolates identified as serogroup 14 (ST9). Cephalosporin resistance (cefotaxime MIC >1 mg l−1) was found in only 0.06 % (n=2/3135) of isolates. Internationally recognized clones (Pneumococcal Molecular Epidemiology Network) accounted for 35 % (n=28/81) of the penicillin non-susceptible isolates and 75 % (n=248/330) of the macrolide-resistant isolates, with ST9 and ST306 predominating. Between 1999 and 2007 we found that 11.6 % (n=18/155) of the penicillin non-susceptible isolates and 4.8 % (n=28/585) of the macrolide-resistant isolates were from serogroups not covered by the 7-valent conjugate pneumococcal vaccine in use in the UK since 2006. Susceptibility to first-line antimicrobial agents for invasive pneumococcal disease in Scotland remained high over the period 1999–2007.
Effect of Cobalt(II) Oxide and Manganese(IV) Oxide on Sintering of Tin(IV) Oxide
Authors: Cerri Jose Alberto , Leite Edson Roberto , Gouvêa Douglas , Longo Elson , Varela Jose Arana
Published: July 2010

Additions of 0. 5 to 2. 0 mol% of CoO or MnO2 onto SnO2 promote densification of this oxide up to 99% of theoretical density. The temperature of the maximum shrinkage rate (TM) and the relative density in the maximum densification rate (p*) during constant sintering heating rate depend on the dopant concentration. Thus, dopant concentration controls the densifying and nondensifying mechanisms during sintering. The densification of SnO2 witih addition of CoO or MnO2 is explained in terms of the creation of oxygen vacancies.
Effect of Grain Size and Test Configuration on the Wear Behavior of Alumina
Authors: Xiong Fei , Manory Rafael R. , Ward Liam , Terheci Mircea , Lathabai Sri
Published: July 2010

The effects of grain size on the tribological behavior of alumina were investigated. Alumina specimens with three different grain sizes, namely 4, 8, and 14 m, were used as pins and disks in a flat‐pin wear test in which the apparent contact area was maintained constant during the test. In contradiction with previously published reports obtained with the regular round pin, our work has found that in this case the alumina wear decreases with increasing grain size. The evidence presented here suggests that the effect of grain size on alumina wear behavior is strongly influenced by the test configuration. Small grains and large grains exhibit two different wear mechanisms: brittle fracture such as grain pull‐out and microchipping as well as abrasive wear are the dominant mechanisms in the small grain size alumina, whereas plastic deformation plays a significant role in the wear behavior of coarser‐grained alumina.
Acid–Base Reactions of Transition Metal Oxides in the Solid State
Authors: Duffy John A.
Published: July 2010

Subsolidus compatibility data exist for a number of ternary oxide systems containing a transition metal oxide. Ternary diagrams, suitable for the present purpose, are limited mainly to those that include FeO, Fe2O3, ZnO, or Cr2O3, and these are examined in the context of Lewis acid–base interaction by considering the electron densities borne by the oxygen atoms or ions. These electron densities can be expressed on the optical basicity scale, and a significant acid–base difference exists between the reactants when they differ markedly in optical basicity. For many reactions the optical basicity difference between the products is much less, suggesting that acid–base neutralization is a major driving force. This principle has been found previously for nontransition metal oxide ternary systems. However, there are notable exceptions, especially in reactions where FeO or ZnO is the end product. This exceptional behavior is examined.
Nonsymmetric Deformation Behavior of Lead Zirconate Titanate Determined in Bending Tests
Authors: Fett Theo , Munz Dietrich , Thun Gerhard
Published: July 2010

Soft lead zirconate titanate (PZT) ceramics exhibit a nonsymmetric deformation behavior, where the tensile strains exceed the compressive strains for a given stress level. This phenomenon affects the strains in bending tests. In addition to the normally determined bending strain that is measured by the curvature of a specimen, an additional length extension occurs that can be used as a high‐sensitive indicator for the occurrence of the nonsymmetric behavior. Furthermore, it will be shown that the pure tensile and compression behavior may be derived from bending tests.
Computer Simulation of Dissociative Adsorption of Water on the Surfaces of Spinel MgAl2O4
Authors: Ming Fang Chang , de With Gijsbertus , Parker Stephen C.
Published: July 2010

Atomistic simulation techniques have been used to model the dissociative adsorption of water onto the low‐index {100}, {110}, and {111} surfaces of spinel MgAl2O4. The Born model of solids and the shell model for oxygen polarization have been used. The resulting structures and chemical bonding on the clean and hydrated surfaces are described. The calculations show that the dissociative adsorption of water on the low‐index surfaces is generally energetically favorable. For the {110} and {111} orientations, the surfaces cleaved between oxygen layers show high absorption and stability. The calculations also show that, for the {111} orientation, the surfaces may absorb chemically water molecules up to ∼90% coverage and have the highest stability. It is suggested that, during fracture, only partial hydration occurs, leading to cleavage preferentially along the {100} orientation.
Transmission Electron Microscopy and Electron Energy‐Loss Spectroscopy Study of Nonstoichiometric Silicon‐Carbon‐Oxygen Glasses
Authors: Turquat Christian , Kleebe Hans‐Joachim , Gregori G. , Walter Steffen , Sorarù Gian D.
Published: July 2010

Crystallization behavior of Si‐C‐O glasses in the temperature range of 1000°–1400°C was investigated using transmission electron microscopy (TEM) in conjunction with electron energy‐loss spectroscopy (EELS). Si‐C‐O glasses were prepared by pyrolysis of polysiloxane networks obtained from homogeneous mixtures of triethoxysilane, TH, and methyldiethoxysilane, DH. Si‐C‐O glass composition depended on the molar ratio of the precursors utilized. At a ratio of TH/DH= 1, the formation of a carbon‐rich glass was observed, whereas a ratio of TH/DH= 9 yielded a Si‐C‐O glass with excess free silicon. Both materials were amorphous at 1000°C, but showed a distinct difference in crystallization behavior on annealing at high temperature. Although TH/DH= 1 revealed a small volume fraction of SiC precipitates in addition to a very small amount of residual free carbon at 1400°C, TH/DH= 9 showed, in addition to SiC crystallites, numerous larger silicon precipitates (20–50 nm), even at 1200°C. Both materials underwent a phase separation process, SiCxO2(1‐x)→xSiC + (1 ‐ x)SiO2, when annealed at temperatures exceeding 1200°C.
Control of Microstructures in α‐SiAlON Ceramics
Authors: Chen Wei‐wu , Sun Wei‐ying , Wang Pei‐ling , Li Ya‐wen , Cheng Yi‐Bing , Yan Dong‐sheng
Published: July 2010

The effects of sintering cycles and doping elements on the microstructures of Ln‐α‐sialon were studied. The results showed that microstructures with an elongated α‐sialon morphology could be obtained through high‐temperature post‐heat treatment (1800–1900°C) or by prolonging soaking times during sintering. Different rare‐earth elements had a profound effect on the microstructure of the resulting α‐sialon. The Ln‐α‐sialon doped with low‐Z‐value elements could easily develop elongated grains with higher aspect ratio.
Improving the Durability of a Biomedical‐Grade Zirconia Ceramic by the Addition of Silica
Authors: Gremillard Laurent , Chevalier Jerome , Epicier Thierry , Fantozzi Gilbert
Published: July 2010

The lifetime of tetragonal zirconia ceramic implants is controlled by their resistance to slow crack growth and low‐temperature degradation (LTD). A decrease of the grain size is often proposed to decrease the effect of LTD on zirconia; however, this decrease also reduces the resistance to crack propagation. An alternative approach is reported here; such an approach consists of introducing a silica glass phase only at triple grain junctions, without changing the grain size. The addition of a small amount of silica (0.5 wt%) decreases the internal stresses, which improves the resistance to LTD without affecting the resistance to crack propagation. These results are discussed from a microstructural standpoint.
Distribution of Cerium Ions in Cerium‐Doped α′‐SiAlON and Its Effect on Grain Morphology
Authors: Xu Fang‐Fang , Bando Yoshio , Wang Chang‐Meng , Mitomo Mamoru
Published: July 2010

Cerium‐doped α′‐SiAlON material was prepared by spark plasma sintering at 1750°C under 30 MPa pressure for 10 min. Yttrium α′‐SiAlON seeds (1 wt%) were added to the starting powder mixture. Recent work showed that up to 45 wt% of α′‐SiAlON phases are formed in the present sintered ceramics. The material presented a microstructure, containing rodlike cerium‐doped α′‐SiAlON crystals. In this paper, transmission electron microscopy and energy dispersive spectroscopy examinations of the α′‐SiAlON grains are reported. The structural analyses revealed a high density of domain boundaries, within which larger amounts of cerium ions were segregated than in the matrix. The density of the domain boundaries was proportional to the amount of incorporated cerium ions. These structural defects eventually dominated the growth habits of the α′‐SiAlON crystals, by modifying the structure of the interstices at the boundary sites. The role of yttrium α′‐SiAlON seeds also is discussed in this paper.
Sequential Combination of Constituent Oxides in the Synthesis of Pb(Fe1/2Nb1/2)O3by Mechanical Activation
Authors: Gao Xingsen , Xue Junmin , Wang John , Yu Ting , Shen Ze Xiang
Published: July 2010

Pb(Fe1/2Nb1/2)O3(PFN) has been successfully synthesized via a novel mechanical activation of mixed oxides and columbite precursor consisting of lead oxide and FeNbO4. A nanocrystalline perovskite phase 5–15 nm in crystallite size was formed after 30 h of mechanical activation at room temperature for both types of starting materials. However, the nanocrystalline PFN phase derived from the mixed oxides of PbO, Fe2O3, and Nb2O5is unstable, and develops pyrochlore phases when calcined at 500°–900°C, while no pyrochlore phase is observed for the material derived from the columbite precursor consisting of PbO and FeNbO5. Different sintering behavior and dielectric properties were also observed between the two types of PFN. These differences are accounted for by the compositional inhomogeneity in the material derived from the mixed oxides, as was revealed by Raman spectroscopic studies. This suggests that mechanical activation is analogous to thermal activation, where the phase development is strongly dependent on the sequence of combining the constituent oxides.
Review article: β‐adrenoceptor blockers for the treatment of portal hypertension
Authors: BURROUGHS A. K. , SPRENGERS D. , McCORMICK P. A.
Published: July 2010

β‐Adrenoceptor blockers always change splanchnic haemodynamics in cirrhotic patients. Azygous blood flow, as a measure of collateral circulation including that through varices, is always reduced, but the effects on portal pressure, whether measured directly or by the wedged hepatic venous pressure, are variable. The initial correlations between a 25% reduction of resting pulse rate and similar percentage reduction in the wedge‐free hepatic venous gradient, has not been reproduced in subsequent studies. Therefore, to study the effect of changes in haemodynamic indices and the likelihood of variceal bleeding, direct measurements of such indices need to be made in clinical trials. At present there are no haemodynamic or clinical factors which can be used to select patients who will have a good therapeutic response to propranolol other than those documented in the first clinical trial of propranolol for the prevention of variceal re‐bleeding from Paris. Thus the hypothesis that β‐adrenoceptor blockers may lessen the incidence of bleeding in cirrhotics, by partially reducing portal pressure or flow or both, needs testing in further clinical studies. The selection criteria of the first clinical trial of propranolol in Paris need to be confirmed. Two subsequent trials, in which patients were not selected but in which many patients had similar clinical characteristics to the Paris patients, could not confirm a therapeutic effect of propranolol. No fatal complications due to propranolol administration have been reported in cirrhotic patients. Complications are reversible. Pharmacological treatment including β‐adrenoceptor blockade appears ideal for trials of primary prevention of variceal bleeding. Some preliminary results including use in decompensated cirrhotics are encouraging. However, as for trials for prevention of re‐bleeding, the design and analysis of such trials needs careful evaluation to take into account the outcome of patients who discontinue medication, whether due to simple non‐compliance or due to side‐effects, and also the influence of abstinence from alcohol on bleeding from varices.
Review: antisecretory drugs: cellular mechanisms of action
Authors: SOLL A. H.
Published: July 2010

Parietal cell secretory function may be inhibited by three mechanisms. (1) Receptors for gastrin, histamine and acetylcholine are present on the canine parietal cell, and parietal cell function may be directly inhibited by specific antagonists for each of these receptors. (2) Receptor activation of parietal cell function is mediated by cyclic AMP‐dependent (histamine) and calcium‐dependent (cholinergic agents and gastrin) mechanisms. The antisecretory action of prostaglandins reflect interference with histamine activation of adenylate cyclase. The current generations of calcium channel blockers have only weak antisecretory actionsin vivoand are unlikely to be useful in clinical practice. (3) A third mechanism of inhibition is blockade of H+/K+‐ATPase by substituted benzimidazoles, such as omeprazole. Each of these three mechanisms provides modalities of potential clinical usefulness for treating acid‐peptic disease. Gastrin and acetylcholine receptors are present on other fundic cells, in addition to the parietal cell. These other cells include the somatostatin cell in the dog fundic mucosa and the histamine‐containing enterochromaffin‐like (ECL) cell present in the fundic mucosa of several species. The relative impact of these receptors on different cell types on the regulation of acid secretion remains uncertain, and is probably variable among different species. One gastrin receptor of considerable importance is the gastrin receptor that exerts a trophic effect on the ECL cell in the fundic mucosa. Sustained hypergastrinaemia in response to profound hypochlorhydria is associated with hyperplasia of this cell type; the elucidation of the conditions that promote this hyperplasia and the clinical consequences of this association are pressing challenges.
Review: long‐acting somatostatin analogues
Authors: LONG R. G.
Published: July 2010

This article reviews the chemistry, actions and chemical applications of somatostatin and its analogues. At present, their gastroenterological use should be considered in patients with the carcinoid syndrome and functioning pancreatic endocrine tumours; in endocrinology there is interest in their use for the management of patients with resistant acromegaly. With these possible exceptions, somatostatin analogues should at present be used only in the context of clinical trials.
Gastrointestinal transit of an enteric‐coated delayed‐release 5‐aminosalicylic acid tablet
Authors: HARDY J. G. , HEALEY J. N. C. , LEE S. W. , REYNOLDS J. R.
Published: July 2010

Gastrointestinal transit of an enteric‐coated, delayed‐release 5‐aminosalicylic acid tablet radiolabelled with indium‐111 has been monitored in a preliminary study with eight healthy subjects using gamma scintigraphy. Gastric emptying of the tablet was delayed by the presence of food in the stomach. Disintegration occurred about 5 hours after the tablet left the stomach. There was close agreement between the tablet disintegration times and the initial detection of drug in the blood. The site of disintegration could be established in most instances; approximately 80% of the doses resulted in drug dispersion within the ascending colon. The coated tablets provide an effective means of drug delivery to the proximal colon.
Evaluation of an enteric‐coated delayed‐release 5‐aminosalicylic acid tablet in patients with inflammatory bowel disease
Authors: HARDY J. G. , HEALEY J. N. C. , REYNOLDS J. R.
Published: July 2010

Gastrointestinal transit of an enteric coated delayed release 5‐aminosalicylic acid tablet radiolabelled with III indium has been monitored in a total of 13 patients with Crohn's disease and ulcerative colitis. More than 70% of the tablets disintegrated in the small intestine, on average 3.2 hours after emptying from the stomach. Dispersed preparation was detected in the proximal colon of all the patients, except one with an ileostomy. Mean peak plasma concentrations of 5‐aminosalicylic acid and its metabolite acetyl‐5‐aminosalicylic acid occurred 3–4 hours after gastric emptying. The tablets provide a reliable means of drug delivery to the ileum and proximal colon.
The effect of a long‐acting somatostatin analogue (SMS 201–995) on intermediary metabolism and gut hormones after a test meal in normal subjects
Authors: FUESSL H. S. , BURRIN J. M. , WILLIAMS G. , ADRIAN T. E. , BLOOM S. R.
Published: July 2010

SMS 201–995 is an octapeptide analogue of somatostatin. The effect of a single subcutaneous (s.c.) injection of 50 μg SMS 201–995 on postprandial intermediary metabolism was investigated in normal subjects. In spite of a long‐lasting post‐prandial suppression of insulin secretion, there were no significant changes in the plasma concentration of alanine, glycerol, 3‐OH‐butyrate or lactate. However, SMS 201–995 impairs carbohydrate tolerance, probably due to inhibition of insulin secretion. Basal and post‐prandial plasma concentrations of the gut regulatory peptides pancreatic glucagon, motilin, pancreatic polypeptide, gastric inhibitory polypeptide, enteroglucagon, gastrin and peptide YY were suppressed up to 5 hours after subcutaneous administration of a single dose of SMS 201–995.
Cimetidine decreases aspirin‐induced gastric mucosal damage in humans
Authors: HOGAN D. L. , THOMAS F. J. , ISENBERG J. I.
Published: July 2010

Aspirin induces gastric mucosal damage in animals and humans. The purpose of this study was to examine whether cimetidine protects the human gastric mucosa from acute aspirin‐induced damage. Eight healthy subjects were studied on 4 separate days. Cimetidine, 400 mg, or placebo was given orally 1 hour before initial endoscopy. The stomach was isolated and atropine given to suppress basal acid secretion. Each study consisted of four 15 min periods during which an acidic test solution was instilled into the stomach. During the second period only, either aspirin (1300 mg, 36 mmol) or control for aspirin (36 mmol HCl) was added to the test solution. Ion fluxes and gastric mucosal potential difference were measured, and endoscopy performed following each test. After placebo, aspirin significantly altered hydrogen ion flux and potential difference versus basal and control. Cimetidine decreased the damaging effect of aspirin. Endoscopic scores increased after aspirin plus placebo, whereas they remained unchanged after aspirin plus cimetidine. Therefore, cimetidine decreased aspirin‐induced gastric mucosal damage in humans. As gastric acidity was identical during all studies, the effect of cimetidine was independent of gastric acid secretion.
A comparative study of the effect of cimetidine and ranitidine on the rate of gastric emptying of liquid and solid test meals in man
Authors: HOUGHTON L. A. , READ N. W.
Published: July 2010

Paired studies were carried out on 18 healthy male volunteers (20.9 ± 1.9 years; mean ± S.D.) to compare the effect of oral doses of the H2‐receptor antagonists, ranitidine and cimetidine, on the rate of gastric emptying of radiolabelled solid and liquid test meals. Oral administration of ranitidine 300 mg accelerated the emptying of a liquid meal from the stomach, but it had no significant effect on the rate of emptying of a solid meal. Oral administration of either 400 or 800 mg cimetidine did not alter the rate of emptying of either the liquid or the solid meals from the stomach.
Review: pancreatic enzyme replacement—applied physiology and pharmacology
Authors: ZENTLER‐MUNRO P. L. , NORTHFIELD T. C.
Published: July 2010

The treatment of pancreatic steatorrhoea can often be improved by attention to the pathophysiological and pharmacological principles involved. Factors influencing the efficacy of pancreatic enzyme replacement include physiological characteristics of the individual patient and pharmaceutical characteristics of the supplement. Different patients may be best suited by different preparations and there is no overall ‘best buy’. The new enteric‐coated microsphere formulations are often most effective, but also more expensive than conventional preparations. Adjunctive H2‐blockade can help appropriately selected patients with resistant steatorrhoea. Knowledge of the underlying cause may guide the choice of supplement and its dose, but trials of different regimens may prove necessary. Successful management, particularly of malnourished patients, involves optimization of dietary fat intake in addition to enzyme replacement.
The effect of calcium channel blockade with nifedipine on splanchnic and systemic haemodynamics in cirrhosis
Authors: MACMATHUNA P. , O'REILLY T. , KELLEHER D. , BARRY M. , FEELY J. , KEELING P. W. N.
Published: July 2010

The splanchnic and systemic haemodynamic effects of a single sublingual dose of nifedipine (slow calcium channel blocker) in nine patients with cirrhosis of the liver and portal hypertension were studied. Nifedipine produced a significant reduction in the mean arterial blood pressure (98±53 vs. 86±5 mmHg, P < 0.05) but did not alter the mean heart rate, portal venous pressure or total liver blood flow. The systemic antihypertensive effect of nifedipine can be achieved without altering liver blood‐flow in patients with chronic liver disease and portal hypertension.
Significance of Campylobacter pylori
Authors: TYTGAT G. N. J. , RAUWS E. A. J.
Published: July 2010

There is an explosion of interest in the role of Campylobacter pylori as a cause of active chronic gastritis. This curved spiraled microorganism can readily be detected within the mucus gel covering the stomach mucosa, especially in patients suffering from peptic ulcer disease or non‐ulcer dyspepsia. To what extent this intriguing microorganism is causally related to peptic ulcer disease remains to be elucidated, but all the evidence which is available so far supports a pathogenetically important role. There appears to be a striking discordance between in‐vitro sensitivity and in‐vivo efficacy of antibiotic therapy. At present, the combination of colloidal bismuth subcitrate and amoxycillin or tinidazole appears most effective in temporary elimination of these microorganisms.
Review: the treatment of primary biliary cirrhosis
Authors: EPSTEIN O.
Published: July 2010

Considerable improvement in quality of life can be achieved by treating the complications of primary biliary cirrhosis. However, once fibrosis, cirrhosis, portal hypertension and hyperbilirubinaemia occur, it is unlikely that ‘medical’ treatment will cure the disorder. Trials of medical therapy should aim to delay or halt the progression of the early phase of the disease and clinicians should refer patients to centres conducting clinical trials. If the disease progresses, and the quality of life is seriously impaired, liver transplantation offers the realistic chance of a new life.
Pharmacological manipulation of adynamic ileus: controlled randomized double‐blind study of ceruletide on intestinal motor activity after elective abdominal surgery
Authors: SADEK S. A. , CRANFORD C. , ERIKSEN C. , WALKER M. , CAMPBELL C. , BAKER P. R. , WOOD R. A. B. , CUSCHIERI A.
Published: July 2010

In a double‐blind placebo‐controlled trial of patients undergoing elective abdominal surgery (n=91), a single intravenous infusion of ceruletide (2.5 ng kg−’min−1’for 1 hour) resulted in audible bowel sounds in 42/47 patients as opposed to 30/44 receiving placebo (P < 0.025). Excessive bowel sounds were noted in 16 patients in the ceruletide group and four receiving placebo (P < 0.01). Significantly more patients (P < 0.01) in the ceruletide group (22/45 versus 9/44) passed flatus per rectum between the second and third post‐operative day. Ceruletide infusion was accompanied by a significant increase in the incidence of nausea and vomiting (P < 0.005, P < 0.0025) but these side effects were short‐lived. These results indicate that ceruletide is likely to be a useful therapeutic agent for acute intestinal adynamic motility disorders.
Effect of oral testosterone treatment on serum concentrations of sex steroids, gonadotrophins and prolactin in alcoholic cirrhotic men
Authors: GLUUD C. , BENNETT P. , SVENSTRUP B. , MICIC S.
Published: July 2010

The aim of this study was to examine the serum concentrations of sex steroids and pituitary hormones in a randomly selected group of alcoholic cirrhotic men participating in a randomized, placebo‐controlled study on the efficacy of oral testosterone treatment on the liver. Before treatment, patients (n= 25) had median serum concentrations of testosterone, oestradiol, non‐protein bound oestradiol, non‐sex hormone binding globulin (SHBG) bound oestradiol and oestrone sulphate which did not differ significantly from those of healthy controls (n= 16), but the patients had significantly (P < 0.01) higher median serum concentrations of oestrone, luteinizing hormone (LH), follicle‐stimulating hormone (FSH) and prolactin.

The patients were randomized to treatment with either oral micronized testosterone (200 mg t.d.s.) or placebo for a median duration of 1 year. In the placebo group (n= 8), hormone concentrations at follow‐up were not significantly different from those at entry apart from a significant (P < 0.05) increase in FSH concentrations. Median concentrations of testosterone, oestrone, and oestrone sulphate increased significantly (P < 0.05) in the testosterone‐treated group (n= 17) when compared with concentrations at entry and concentrations in the placebo group. The testosterone‐treated group had significantly (P < 0.05) higher serum concentrations of non‐protein bound and non‐SHBG bound oestradiol when compared with concentrations at entry, but no significant changes were observed regarding serum oestradiol and prolactin concentrations. Both LH and FSH concentrations decreased significantly (P < 0.05) in the testosterone‐treated group when compared with concentrations at entry and concentrations in the placebo group.
Review: the treatment of hepatocellular carcinoma
Authors: DUNK A. A. , THOMAS H. C.
Published: July 2010

Surgical resection offers the only realistic hope of cure in hepatocellular carcinoma (HCC) but is usually not possible, either because the tumour is widespread throughout the liver at diagnosis, or because liver function is adversely affected by concomitant cirrhosis. The results of operation in early asymptomatic disease are, however, encouraging and efforts should be made to screen regularly the cirrhotic population at risk of HCC development.

The prognosis for inoperable patients remains gloomy, though exciting new treatment methods exist which require extensive evaluation. An anthracycline given as single agent intravenous therapy is probably the current treatment of choice for inoperable patients, though only 20–30% will show a response. Intra‐arterial therapy has not yet been convincingly shown to have any advantages over intravenous therapy.

The evaluation of clinical trials in HCC would be made easier if response criteria were standardized and universally adopted, and if trials were properly controlled and of sufficient sample size to test adequately the hypothesis in question.
Twenty‐four‐hour intragastric measurements in twenty healthy subjects: effect of enisoprost, a novel and potent antisecretory and antipeptic synthetic E1 prostaglandin
Authors: THOMSON A. B. R. , McCULLOUGH H. N. , KIRDEIKIS P. , ZUK L. , SIMPSON I. , COOK D. J. , WILDEMAN R. A. , BRUNET K. , FISHER D. , PINCHBECK B. , GOODFELLOW J. , WALKER K.
Published: July 2010

Gastric aspiration was performed continuously overnight and at hourly intervals during the daytime in 20 healthy male volunteers. Medications used included enisoprost 100, 200 or 400 μg, misoprostol 200 μg and placebo, given at bedtime. Each dose of enisoprost markedly inhibited nocturnal mean acid output, hydrogen ion activity, pH and peptic activity. The duration of these effects was up to 10 h. Misoprostol, given at bedtime, also decreased acid secretion, but the effect was significantly less than that observed with any of the doses of enisoprost. A dose—response effect for enisoprost was found for the mean nocturnal hydrogen ion activity and pH, as well as for maximum pH attained. Although enisoprost, given at bedtime, had a marked inhibitory effect on acid and pepsin secretion for the overnight interval, this did not result in rebound hyperacidity or a rise in serum total gastrin concentration. The results of this study suggest that enisoprost should be tested by clinical trial for the treatment of peptic ulcer disease.
Six years of continuous cimetidine treatment in peptic ulcer disease: efficacy and safety
Authors: BARDHAN K. D. ,   FOR THE ANGLO‐IRISH CIMETIDINE LONG‐TERM STUDY GROUP
Published: July 2010

The management of peptic ulcer disease with up to 6 years of continuous cimetidine treatment has been studied at four centres in the UK and Ireland. Cimetidine, 1 g daily for up to 12 weeks, was used to heal duodenal or gastric ulceration, alternating with 400 mg each night to maintain remission.

After an initial healing phase, 402 patients started maintenance therapy. Classical life‐table analyses showed that after 5 years one‐quarter of the patients had suffered a symptomatic relapse, about half during the first year of maintenance treatment. Prevalence analyses (reflecting the cyclical nature of H2‐antagonist use in peptic ulcer disease) over 6 years show that, on average, over 97% remain free of symptomatic ulceration at any one time. Patients ‘lost’ to the study due to withdrawal or default may, however, bias the results. A model designed to account for these estimates that during the long‐term management of peptic ulcer with cimetidine, on average around 95% of patients remain free of symptomatic ulceration at any one time.

Safety studies, including haematological and biochemical testing over the whole period, revealed no previously unknown adverse reaction. Seven patients were withdrawn for events considered to be related to the drug. Eleven patients died; none of the deaths appears to be connected with the treatment.

It is concluded that long‐term use of cimetidine is effective in the management of peptic ulcer disease, and continuous treatment for up to 6 years has not revealed any previously unknown hazard.
The anti‐secretory effect and pharmacokinetics of omeprazole in chronic liver disease
Authors: McKEE R. F. , MacGILCHRIST A. J. , GARDEN O. J. , FORREST J. A. H. , CARTER D. C.
Published: July 2010

The anti‐secretory effects and pharmacokinetics of omeprazole were investigated in ten patients with chronic liver disease. Plasma omeprazole concentrations were measured after a 10‐mg intravenous dose of omeprazole and on the first and seventh days of a 7‐day course of 10 mg oral omeprazole daily. Pentagastrin tests were performed on the day before oral omeprazole was commenced and 24 h after the last oral dose.

The pre‐treatment basal and peak gastric acid outputs were low (mean rates of 1.44 mmol/h and 9.26 mmol/h, respectively) and following 7 days of oral 10 mg omeprazole daily, were lowered by 95% and 90% respectively. Following 10 mg intravenous omeprazole, plasma clearance was reduced, and plasma half‐life and area under the concentration curve were increased, in comparison with previous studies in healthy subjects. The plasma concentration curves for oral and intravenous doses were very similar. After both the first and seventh oral doses, maximum plasma concentration and area under the curve were higher than in healthy subjects. No accumulation of omeprazole was demonstrated.

The pharmacokinetics of omeprazole in chronic liver disease could be influenced by low gastric acidity, poor liver function and/or portasystemic shunting. A dose of 10 mg omeprazole daily has been shown to be an effective anti‐secretory agent in chronic liver disease.