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  • 1
    Electronic Resource
    Electronic Resource
    Impurity-induced-disordered phase modulators in AlGaAs/GaAs quantum well and double-heterostructure waveguides (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 728-730 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Results for two new channel waveguide phase modulators formed by impurity-induced disordering (IID) with Zn diffusion in AlGaAs/GaAs are presented. One device utilizes side diffusion into ridges of single quantum well material and the other utilizes surface diffusion into double-heterostructure material. Waveguide loss for both TE and TM polarizations, and effective index steps calculated from observed mode profiles are reported. TE/TM mode conversion was observed without bias under certain conditions. Initial results for phase modulation are in agreement with expectations and appear not to be affected by the IID.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99816
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  • 2
    Electronic Resource
    Electronic Resource
    Relating the chirp parameter to the number of quantum wells in GaAs/AlGaAs waveguide modulators (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 718-720 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: For wavelengths near the quantum well absorption edge it is found that fewer quantum wells favor ideal phase modulation in GaAs/AlGaAs waveguide modulators. This is due to the dominance of the linear electro-optic effect over quantum absorption effects in the separate confinement waveguide. For TE polarization, it is found that the chirp parameter varies from 〈1 to 〉10 at −5 V and λ=0.89 μm in actual devices depending on the number of wells. The data fit estimates from theory. For TM polarization no dependence was observed as expected. For an integrated laser/phase modulator (with different absorption edges) a 4-well structure may be near optimum to maximize the modulation efficiency and to still have low laser threshold current.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101784
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  • 3
    Electronic Resource
    Electronic Resource
    High-energy argon-ion implantation for waveguide formation in (AlGa)As/GaAs multilayers (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 2051-2053 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have intermixed GaAs/(AlGa)As multiquantum structures for waveguides and lasers by 3 MeV Ar implantation and 850 °C, 30 min closed-tube annealing. Buried-heterostructure lasers defined by Ar mixing had threshold currents of 100 mA for 370-μm-long devices. As waveguides for 1.15 μm light, the devices exhibited losses of 25 cm−1 in the annealed, implanted regions, and 15 cm−1 in unimplanted regions defined by adjacent implants. Analysis of the results illustrates important considerations for implant mixing for waveguide formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104115
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  • 4
    Electronic Resource
    Electronic Resource
    Spiramycin in triple therapy of Helicobacter pylori-associated peptic ulcer disease. An open pilot study with 12-month follow-up (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 9 (1995), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Spiramycin (Rovamycin) is a well-established macrolide antibiotic with good anti-Helicobacter pylori activity in vitro. It is acid-stable and found in high concentration in various body fluids and cells after oral administration. Its anti-H. pylori activity in vivo has not yet been tested. Methods: Twenty-five consecutive patients with endoscopically verified peptic ulcer and a positive biopsy urease test were given spiramycin tables 1.5 MIU instead of oxytetracycline 500 mg q.d.s. in our triple therapy regimen with bismuth subnitrate suspension 10 mL (150 mg bismuth subnitrate) q.d.s. and metronidazole 400 mg t.d.s. for 10 days. Bismuth was taken between meals and spiramycin and metronidazole with meals. Re-endoscopy and 14C-urea breath test were performed 4 weeks after completion of therapy. Those who were H. pylori negative according to the breath test returned for 1-year follow-up. Results: Per protocol analysis at 4 weeks showed that 21 out of 23 patients were H. pylori negative and had healed ulcers. These 21 patients were persistingly H. pylori negative and had no ulcers at 1-year follow-up. H. pylori eradication and ulcer healing rates were thus 91.3%; 95 % confidence interval from 72.0% to 98.9%. Side-effects limiting daily activity were significantly less frequent than we have experienced previously using oxytetracycline in triple therapy. Conclusions: Spiramycin appears to be an alternative to tetracycline in the triple therapy of H. pylori infection. Further studies to position spiramycin as an anti-H. pylori drug are warranted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2036.1995.tb00371.x
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of ferrous sulphate and non-ionic iron–polymaltose complex on markers of oxidative tissue damage in patients with inflammatory bowel disease (2005)
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 22 (2005), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background : Iron deficiency is a common complication of inflammatory bowel disease. Oral iron therapy may reinforce intestinal tissue injury by catalyzing production of reactive oxygen species.Aim : To compare the effects of ferrous sulphate and non-ionic iron–polymaltose complex on markers of oxidative tissue damage and clinical disease activity in patients with inflammatory bowel disease.Methods : Forty-one patients with inflammatory bowel disease and iron deficiency were randomized to treatment with ferrous sulphate 100 mg twice a day or iron–polymaltose complex 200 mg once a day for 14 days.Results : Following ferrous sulphate, plasma malondialdehyde increased (P = 0.02), while urine 8-isoprostaglandin F2α and plasma antioxidants did not change significantly. Iron–polymaltose complex did not change plasma malondialdehyde, urine 8-isoprostaglandin F2α or plasma antioxidants. Comparing the two treatments, changes in plasma malondialdehyde tended to differ (P = 0.08), while urine 8-isoprostaglandin F2α and plasma antioxidants did not differ. Neither ferrous sulphate nor iron–polymaltose complex altered clinical disease activity indices.Conclusions : Ferrous sulphate increased plasma malondialdehyde, a marker of lipid peroxidation. Comparing treatment with ferrous sulphate and iron–polymaltose complex, changes in plasma malondialdehyde tended to differ. Clinical disease activity was unchanged after both treatments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2036.2005.02652.x
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  • 6
    Electronic Resource
    Electronic Resource
    Wide gastric antrum and low vagal tone in patients with diabetes mellitus type 1 compared to patients with functional dyspepsia and healthy individuals (1996)
    Springer
    Digestive diseases and sciences 41 (1996), S. 9-16 
    Details
    ISSN: 1573-2568
    Keywords: abdominal discomfort ; antral distension ; diabetes mellitus type 1 ; gastric antrum ; two-dimensional ultrasonography ; vagal tone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Autonomous neuropathy in patients with diabetes is associated with dysmotility and abdominal discomfort. The disturbances resemble to some extent those seen in patients with functional dyspepsia. To gain further insight into the disorders, we compared patients with long-standing diabetes, patients with functional dyspepsia, and healthy individuals with respect to abdominal symptoms, width of gastric antral area, and autonomic nerve function. We investigated 42 type I diabetic outpatients by structured interview for abdominal discomfort, ultrasonography of the gastric antrum, assessment of vagal and sympathetic nerve function by respiratory sinus arrhythmia and skin conductance, and measurement of blood sugar and HbAlc. Immediately after a standard meal of soup with meat, 21 (50%) of the 42 patients with diabetes complained of abdominal discomfort (pain, bloating, fullness), which was significantly less frequent (95% CI of difference 0.03–0.5) than previously seen in patients with functional dyspepsia (76%), and significantly more frequent (95% CI of difference 0.3–0.6) than that seen in healthy individuals (4%). Bloating was the most marked postprandial complaint. Mean fasting antral area was significantly wider in patients with diabetes (mean 4.9 cm2,sd 1.7) compared to healthy individuals (mean 3.5 cm2,sd 1.2), 95% CI of difference 0.6–2.2 cm2. Mean postprandial antral area was 14.8 cm2 (sd 4.6) in the patients with diabetes, which is insignificantly wider than in patients with functional dyspepsia (mean 13.0 cm2,sd 4.0) but significantly wider (95% CI of difference 1.9–6.5 cm2) than that seen in healthy individuals (mean 10.6 cm2,sd 3.8). The mean respiratory sinus arrhythmia was 0.7 beats/min (sd 0.7) in the patients with diabetes, which was insignificantly lower than that seen in patients with functional dyspepsia (2.1 beats/min,sd 4.5), and significantly lower (99% CI of difference 3.8–7.1 beats/min) compared to healthy individuals (6.2 beats/min,sd 3.8). It is concluded that patients with diabetes have a wider gastric antrum and more discomfort after a meal than healthy individuals. Compared to patients with functional dyspepsia, patients with diabetes have a wider postprandial antrum but fewer symptoms. The very low vagal tone seen in patients with diabetes may play an important role in the pathogenesis of their gastric motility disturbance and postprandial abdominal discomfort.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02208577
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  • 7
    Electronic Resource
    Electronic Resource
    Impaired accommodation of proximal stomach to a meal in functional dyspepsia (1996)
    Springer
    Digestive diseases and sciences 41 (1996), S. 689-696 
    Details
    ISSN: 1573-2568
    Keywords: accommodation ; adaptive relaxation ; stomach ; gastric emptying ; ultrasonography ; gastric physiology ; functional dyspepsia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In patients with functional dyspepsia, scanning by a novel ultrasonographic method was carried out to investigate postprandial accommodation of the proximal stomach. Twenty patients with functional dyspepsia and 20 controls were scanned fasting in a sitting position after drinking 500 ml meat soup. Images were recorded up to 25 min after the ingestion period using an ultrasound sector scanner with a 3.25-MHz transducer. The area in a sagittal section and the maximal diameter in an oblique frontal section were chosen as the main variables for calculating the emptying fraction of the proximal stomach, defined as: (aV 2.5min-aV actual/aV 2.5min. All subjects were asked to score total symptoms (1–9) provoked by the meal. From 7.5 to 25 min after the ingestion period the patients exhibited both smaller area in the sagittal section (P〈0.018) and shorter diameter in the frontal section (P〈0.046) compared with healthy controls, and they suffered more symptoms in response to the meal (P=0.002). Dyspeptic patients revealed higher emptying fractions (P=0.0005, ANOVA), andH. pylori status did not influence the emptying fractions. Diagnostic sensitivity of the method at 20 min postprandially was 70% and the specificity was 65%. Patients with functional dyspepsia have impaired accommodation of the proximal stomach to a meal, temporarily related to symptom induction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02213124
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