Search Results - (Author, Cooperation:M. Fried)

2014-05-24

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Adolescent ; Adult ; Animals ; Antibodies, Protozoan/blood/*immunology ; Antigens, Protozoan/*immunology ; Child ; Erythrocytes/*parasitology ; Hepatocytes/immunology/parasitology ; Humans ; Immunoglobulin G/blood/immunology ; Kenya ; Malaria/prevention & control ; Malaria Vaccines/*immunology ; Malaria, Falciparum/*prevention & control ; Mice ; Plasmodium berghei/immunology ; Plasmodium falciparum/*growth & development/immunology ; Protozoan Proteins/*immunology ; Recombinant Proteins/immunology ; Schizonts/*growth & development ; Young Adult

1089-7550

AIP Digital Archive

Physics

Bonding of a 1360-nm-thick single crystalline silicon membrane onto an oxidized wafer was enhanced by ion mixing using 1250 keV 14N+ ion implantation. The oxidized wafer was covered by a thin, thermally grown oxide (134 nm) and implantation was performed either in random or in channeling directions through the membrane. Ion doses were in the range of 0.5×1016 to 5×1016 atoms/cm2. Implantation was followed by an annealing at 1000 °C for 0.5 h in nitrogen gas to remove the radiation defects. Due to the effect of implantation, the bonding quality was very good in all cases. In addition, results of Rutherford backscattering spectroscopy and transmission electron microscopy showed that using channeled implantation with a dose of 0.5×1016 atoms/cm2, the adherent silicon layer was of high quality (∼1.5×103 dislocations/cm2) and the interface remained sharp.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Measuring with a spectroscopic ellipsometer (SE) in the 1.8–4.5 eV photon energy region we determined the complex dielectric function (ε = ε1 + iε2) of different kinds of amorphous silicon prepared by self-implantation and thermal relaxation (500 °C, 3 h). These measurements show that the complex dielectric function (and thus the complex refractive index) of implanted a-Si (i-a-Si) differs from that of relaxed (annealed) a-Si (r-a-Si). Moreover, its ε differs from the ε of evaporated a-Si (e-a-Si) found in the handbooks as ε for a-Si. If we use this ε to evaluate SE measurements of ion implanted silicon then the fit is very poor. We deduced the optical band gap of these materials using the Davis–Mott plot based on the relation: (ε2E2)1/3 ∼ (E− Eg). The results are: 0.85 eV (i-a-Si), 1.12 eV (e-a-Si), 1.30 eV (r-a-Si). We attribute the optical change to annihilation of point defects.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Several-parameter fitting of multiple-angle-of-incidence ellipsometry data is developed to characterize near-surface layers on semiconductors damaged by implantation. The damage depth profiles were described by either rectangular, trapezoid-type, or coupled half-Gaussian (realistic) optical models. The rectangular model has three parameters: the average damage level and effective thickness of the implanted layer, plus the thickness of the native oxide. The trapezoid-type model is enhanced with a fourth parameter, the width of the back (a/c) interface. The realistic optical model consists of a stack of layers with fixed and equal thicknesses and damage levels determined by a depth profile function (presently the coupled half-Gaussians). Five parameters were used: the center, the height, and two standard deviations of the profile, plus the thickness of the native oxide. The complex refractive index of each layer is calculated from the actual damage level by the Bruggeman effective medium approximation. The method was tested on Ge-implanted silicon layers (at a wavelength of 632.8 nm) and was cross checked with high depth resolution Rutherford backscattering spectrometry and channeling.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

A several-parameter fitting of spectroscopic ellipsometry data is developed to characterize near-surface layers in semiconductors damaged by implantation. The damage depth profiles are described by either rectangular, trapezoid-type, or coupled half-Gaussian (realistic) optical models. The rectangular model has three parameters: the average damage level, the effective thickness of the implanted layer, and the thickness of the native oxide. The trapezoid-type model is enhanced with a fourth parameter, the width of the amorphous/crystalline interface. The realistic optical model consists of a stack of layers with fixed and equal thicknesses. The damage levels are determined by a depth profile function (presently coupled half-Gaussians). Five parameters are used: the position of the maximum, the height, and two standard deviations of the profile, plus the thickness of the native oxide. The complex refractive index of each layer is calculated from the actual damage level by the Bruggeman effective medium approximation. The optical models were tested on Ge-implanted silicon samples and cross checked with high-depth-resolution Rutherford backscattering spectrometry and channeling.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Polysilicon layers with thicknesses between 8 and 600 nm deposited by low-pressure chemical vapor deposition at temperatures ranging from 560 to 640 °C were characterized by spectroscopic ellipsometry (SE) to determine the layer thicknesses and compositions using multilayer optical models and the Bruggeman effective-medium approximation. The dependence of the structural parameters on the layer thickness and deposition temperature have been investigated. A better characterization of the polysilicon layer is achieved by using the reference data of fine-grained polysilicon in the optical model. The amount of voids in the polysilicon layer was independently measured by Rutherford backscattering spectrometry (RBS). The SE and RBS results show a good correlation. The comparison of the surface roughness measured by SE and atomic force microscopy (AFM) shows that independently of the AFM window sizes, a good correlation of the roughness determined by SE and AFM was obtained. © 2000 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

To overcome difficulties which arise when either the series resistance is too high or the Schottky barrier height is too low, a new and simple method was developed to measure barrier height. Crucial point is the application of a "one-sided'' configuration. This method was successfully applied to the GdSi2 system, where φB =0.38±0.005 eV was measured.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Silicon-on-insulator structures implanted by 200-keV nitrogen with a dose of 7.5×1017 atoms/cm2 were studied by spectroscopic ellipsometry (SE). The SE measurements were carried out in the 300–700-nm wavelength (4.13–1.78-eV photon energy) range. For the analysis of the SE data we used the conventional method of assuming appropriate optical models and fitting the model parameters (layer thicknesses and compositions) by linear regression. Calculated data were in good agreement with measurements when a seven-layer model, consisting of surface oxide layer, thick silicon layer, upper two interface layers, thick nitride layer, and lower two interface layers, was applied. Results obtained by SE were compared with those from Rutherford backscattering spectroscopy (RBS) and transmission electron microscopy. In contrast with RBS measurements, we found that the sensitivity of our optical model combined with the fitting technique was good enough to resolve the silicon-rich transition layers at the upper and lower interfaces of the buried nitride layer.

Electronic Resource

1365-2516

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary.  Liver biopsy plays a pivotal role in the management of patients with a variety of liver diseases, including chronic hepatitis C virus. The major risk of the procedure is the potential for significant haemorrhagic complications. Although the data are limited, the procedure does not appear to pose excessive risk to the patient with inherited disorders of coagulation, provided that adequate haemostasis can be achieved prior to the liver biopsy. This requires close coordination of care between the hepatologist and the haematologist. Indications for liver biopsy should be the same in patients with haemophilia as in other populations.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The aim of this study was to assess the caries incidence and plaque accumulation in schoolchildren at caries risk, after brushing the teeth fortnightly with gels containing 0, 0.4% F, 1.25% F as amine fluoride (AmF) or the common amine fluoride toothpaste containing 0.125% F. The study was conducted double blind over an 18–month period, and after 6 months discontinuation of brushing. Only the group that brushed with the 1.25% AmF gel showed a significant decrease in caries development compared to the group that brushed with the 0.125% AmF toothpaste. During the 6-month discontinuation period, the incidence of caries increased in all groups: the differences in caries development between all groups were not significant. Plaque indices were significantly lower in the AmF-treated groups. The highest fluoride concentration in the gel reduced the development of caries to zero, probably due to increased fluoride levels in the oral milieu of caries risk children. In order to maintain a positive effect of fluoride over an extended time period, caries-prone subjects should continue an initiated fluoride programme.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background : Gastro-oesophageal reflux disease (GERD) and constipation have a major impact on public health; however, the wide variety of treatment options presents difficulties for recommending therapy. Lack of definitive guidelines in pharmacy and general practice medicine further exacerbates the decision dilemma.Aims : To address these issues, a panel of experts discussed the principles and practice of treating GERD and constipation in the general population and in pregnancy, with the aim of developing respective treatment guidelines.Results : The panel recommended antacids ‘on-demand’ as the first-line over-the-counter treatment in reflux, and as rescue medication for immediate relief when reflux breaks through with proton pump inhibitors. Calcium/magnesium-based antacids were recommended as the treatment of choice for pregnant women because of their good safety profile. In constipation, current data do not distinguish a hierarchy between polyethylene glycol (PEG)-based laxatives and other first-line treatments, although limitations are associated with stimulant- and bulk-forming laxatives. Where data are available, PEG is superior to lactulose in terms of efficacy. In pregnancy, PEG-based laxatives meet the criteria for the ideal treatment.Conclusions : The experts developed algorithms that present healthcare professionals with clear treatment options and management strategies for GERD and constipation in pharmacy and general practice medicine.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background : Modern medical imaging modalities can trace labelled oral drug dosage forms in the gastrointestinal tract, and thus represent important tools for the evaluation of their in vivo performance. The application of gastric-retentive drug delivery systems to improve bioavailability and to avoid unwanted plasma peak concentrations of orally administered drugs is of special interest in clinical and pharmaceutical research.Aim : To determine the influence of meal composition and timing of tablet administration on the intragastric performance of a gastric-retentive floating tablet using magnetic resonance imaging in the sitting position.Methods : A tablet formulation was labelled with iron oxide particles as negative magnetic resonance contrast marker to allow the monitoring of the tablet position in the food-filled human stomach. Labelled tablet was administered, together with three different solid meals, to volunteers seated in a 0.5-T open-configuration magnetic resonance system. Volunteers were followed over a 4-h period.Results : Labelled tablet was detectable in all subjects throughout the entire study. The tablet showed persistent good intragastric floating performance independent of meal composition. Unfavourable timing of tablet administration had a minor effect on the intragastric tablet residence time and floating performance.Conclusion : Magnetic resonance imaging can reliably monitor and analyse the in vivo performance of labelled gastric-retentive tablets in the human stomach.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Introduction : Esomeprazole, the first proton pump inhibitor to be developed as an optical isomer, has demonstrated more effective healing vs. omeprazole and lansoprazole in patients with reflux oesophagitis (RO). However, RO recurs in a high proportion (∼80%) of these patients within 12 months of initial therapy, highlighting the importance of maintenance treatment. Previous studies have shown esomeprazole to be effective as maintenance therapy in healed RO patients.Aim:  This study was conducted to compare esomeprazole 20 mg once daily (o.d.) with lansoprazole 15 mg o.d. for the prevention of recurrence of RO.Methods:  1391 patients with endoscopically verified RO (LA classification) were enrolled in this randomized, double-blind, parallel-group, multicentre trial. During the initial healing phase of the study, all patients received 4–8 weeks' open treatment with esomeprazole 40 mg: 1236 healed (identified by endoscopy at 4 and 8 weeks) and symptom-free (i.e. no heartburn or acid regurgitation) patients were randomized to 6 months' maintenance treatment with esomeprazole 20 mg o.d. or lansoprazole 15 mg o.d.. Time to relapse (relapse of RO and/or discontinuation due to symptom recurrence) was analysed using a log-rank test.Results:  Esomeprazole maintained a significantly higher proportion of patients in remission than lansoprazole over the 6-month course of treatment (P 〈 0.0001, intention-to-treat analysis). After 6 months' treatment, 83% of esomeprazole recipients were in remission compared with 74% of lansoprazole recipients (life-table estimates). Esomeprazole gave a longer time to relapse than lansoprazole irrespective of baseline LA Grade, significantly so for baseline LA Grades B, C and D (P 〈 0.05 for each comparison). Significantly more patients were free from heartburn in the esomeprazole group compared with the lansoprazole group at 1, 3 and 6 months (P 〈 0.05). Significant differences at 6 months between esomeprazole 20 mg o.d. and lansoprazole 15 mg o.d. were also observed for control of epigastric pain and acid regurgitation (P 〈 0.05 and P 〈 0.001, respectively). Both treatment regimens were well tolerated.Conclusion:  Esomeprazole 20 mg o.d. is a more effective maintenance treatment than lansoprazole 15 mg o.d. for symptom-free patients with healed RO.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Controlled delivery of drugs to the small intestine in relation to emptying of an ingested meal is important in various pathophysiological conditions. We investigated the effects of different food consistencies and the amount of co-ingested liquid on the intragastric distribution of a contrast marker.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:Five healthy subjects received four meals (each 650 kcal: A, mashed potato with 100 mL water; B, rice with 100 mL water; C, hamburger meal with 100 mL water; D, hamburger meal with 300 mL water). A capsule filled with gadolinium tetra-azacyclododecane tetra-acetic acid solution (as contrast marker) was ingested following meal termination, and its intragastric distribution was assessed by magnetic resonance imaging.〈section xml:id="abs1-3"〉〈title type="main"〉Results:Initially, marker distribution was confined to the fundus, and subsequently extended along the inner curvature of the stomach. The maximum distribution volume of the marker was lower in meal A than in meal B (P 〈 0.05). No differences in marker distribution were observed when the hamburger meal was given with 100 or 300 mL water.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:The intragastric distribution kinetics of the marker gadolinium tetra-azacyclododecane tetra-acetic acid appeared to depend on meal consistency, but not on the amount of water co-ingested. Three-dimensional magnetic resonance imaging allows detailed analysis of the intragastric distribution of a drug model in relation to meal emptying and intragastric meal distribution.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

To evaluate therapies available for the treatment of irritable bowel syndrome, and provide consensus recommendations for their use, a total of 51 double-blind clinical trials using bulking agents, prokinetics, antispasmodics, alosetron, tegaserod and antidepressants were selected. The quality of studies was assessed using 5-point scale. Meta-analyses were performed on all studies, and on ‘high-quality studies’. The efficacy of fibre in the global irritable bowel syndrome symptoms relief (OR: 1.9; 95% CI:1.5–2.4) was lost after exclusion of low-quality trials (OR: 1.4; 95% CI: 1.0–2.0, P = 0.06). When excluding the low-quality trials, an improvement of global irritable bowel syndrome symptoms with all antispasmodics (OR: 2.1; 95% CI:1.8–2.9) was maintained only for octylonium bromide, but on the basis of only two studies. Antidepressants were effective (OR: 2.6, 95% CI: 1.9–3.5), even after exclusion of low-quality studies (OR: 1.9, 95% CI: 1.3–2.7). Alosetron (OR: 2.2; 95% CI: 1.9–2.6) and tegaserod (OR: 1.4; 95% CI: 1.2–1.5) showed a significant effect in women. We recommend the use of tegaserod for women with irritable bowel syndrome with constipation and alosetron for women with severe irritable bowel syndrome with diarrhoea. Antidepressants can be beneficial for irritable bowel syndrome with diarrhoea patients with severe symptoms. Loperamide can be recommended in painless diarrhoea. Evidence is weak to recommend the use of bulking agents in the treatment of irritable bowel syndrome with constipation.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background : The intermittent loss of oil or liquid faeces (‘spotting’) is an adverse effect that occurs in obese patients during treatment with the lipase inhibitor orlistat; the pathophysiology is unknown.Aim : To investigate the effects of orlistat on anorectal sensorimotor function and continence.Methods : Obese subjects susceptible to spotting were identified by an unblind trial of orlistat. Obese spotters (n = 15) and non-spotters (n = 16) completed a randomized, double-blind, cross-over trial of orlistat and placebo. Anorectal function was assessed by rectal barostat and anal manometry, together with a novel stool substitute retention test, a quantitative measurement of faecal continence.Results : Orlistat increased stool volume and raised faecal fat and water. Treatment had no effect on anorectal motor function, but rectal sensation was reduced; on retention testing, the volume retained was increased. Subjects susceptible to spotting had lower rectal compliance, heightened rectal sensitivity and weaker resting sphincter pressure than non-spotters. On retention testing, gross continence was maintained; however, spotters lost small volumes of rectal contents during rectal filling.Conclusion : Treatment with orlistat has no direct adverse effects on anorectal function or continence. Spotting occurs during treatment with orlistat when patients with sub-clinical anorectal dysfunction are exposed to increased stool volume and altered stool composition.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Aim : To compare the efficacy of esomeprazole, 20 mg once daily, vs. lansoprazole, 15 mg once daily, for the maintenance treatment of patients with healed reflux oesophagitis.Methods : During the initial open healing phase, 1391 patients with endoscopically verified reflux oesophagitis and a history of heartburn, with or without acid regurgitation, received esomeprazole 40 mg for 4–8 weeks. Patients who were healed (identified by endoscopy at 4 or 8 weeks) and symptom free were then randomized to receive 6 months of treatment with esomeprazole, 20 mg once daily, or lansoprazole, 15 mg once daily.Results : Esomeprazole, 20 mg once daily, maintained a significantly higher proportion of patients in remission than lansoprazole, 15 mg once daily, over 6 months [83% (95% CI, 80–86%) of esomeprazole recipients compared with 74% (95% CI, 70–78%) of lansoprazole recipients; P 〈 0.0001; life table estimates]. When data were analysed according to baseline Los Angeles grade classification, esomeprazole, 20 mg once daily, achieved consistently higher remission rates across all grades of disease severity, whereas the efficacy of lansoprazole decreased to a greater extent with increasing severity of reflux oesophagitis.Conclusion : Esomeprazole, 20 mg once daily, is more effective than lansoprazole, 15 mg once daily, in maintaining remission in patients with healed reflux oesophagitis.

Electronic Resource

0005-2760

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Medicine

Physics

Electronic Resource

0005-2760

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Medicine

Physics

Electronic Resource

0006-291X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource