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  • 11
    Electronic Resource
    Electronic Resource
    Effect of the elastic modulus of the matrix on magnetostrictive strain in composites (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 1159-1161 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of the matrix material on the magnetostriction of composites containing highly magnetostrictive particles has been studied. Experimental results showed that the elastic modulus of the matrix is an important factor determining the bulk magnetostriction of the composite. For a series of composites with the same volume fraction of magnetostrictive particles but different matrix materials, the bulk magnetostriction was found to increase systematically with decreasing elastic modulus of the matrix. A model theory for the magnetostriction of such composites has been developed, based on two limiting assumptions: uniform strain or uniform stress inside the composite. The theory was then used to predict the magnetostriction of the entire material from the volume fractions of the components, their elastic moduli and magnetostrictions. These predictions were in agreement with the experimental results. It is concluded that to obtain a high magnetostriction and adequate mechanical properties of a composite, the elastic moduli of the magnetostrictive phase and the matrix should be as close as possible in value. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123473
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  • 12
    Electronic Resource
    Electronic Resource
    A generalized solidification model and microstructural verification for the Nd–Fe–B–Ti–C system processed by rapid solidification : The 41st annual conference on magnetism and magnetic materials (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 4459-4461 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: For the Nd2Fe14B (2-14-1) compound, the optimal grain size should be smaller than the size of the single domain size of 150 nm. Transition metal carbides (TMC) also reduce the quench rate necessary to achieve the optimal or overquenched condition. This allows inert gas atomization (IGA) to produce viable magnetic materials. In this article we will demonstrate that optimal microstructure for the 2-14-1 can be produced by IGA with the addition of TiC. Moreover, a solidification model will be presented to show (1) how recalescence is a critical feature to the evolution of the microstructure in rapidly solidified materials and (2) the role TMC and other solute phases have on inhibiting grain growth so that lower quench rates can be employed. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.364975
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  • 13
    Electronic Resource
    Electronic Resource
    Magnetoelastic properties of terfenol composites (abstract) : The 41st annual conference on magnetism and magnetic materials (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 5423-5423 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Recent work was undertaken to identify the possibility of using composite Terfenol, consisting of Tb–Dy–Fe in a nonmagnetic, nonmetallic binder, for magnetoelastic sensor applications in which the material needs to be formed into complex shapes, and in which the high levels of magnetostriction obtained in Tb–Dy–Fe alone are unnecessary. Recent results reported by Sandlund et al.1 have indicated the possible use of such a material in high frequency applications. In this work we have studied the material for low frequency, or even dc applications, in which the material could be used to sense an applied torque. The results showed that these composite materials need magnetic fields of typically 800 kA/m to obtain the magnetostriction levels of 350 ppm reported elsewhere.2 Similar work by Peters3 needed fields of over 1 MA/m to obtain magnetostrictive strains beyond 100 ppm. Such field strengths are impractical for low power devices. From the present work, 38 μm Terfenol powder in an epoxy or polymer binder gave magnetostrictive strains of 120 ppm and above for field strengths of 100 kA/m, which is much more appropriate for small low power sensors. A benchmark sensitivity of 18 μ T/N m for measurement of torque levels over the range ± 10 Nm was set based on the response of nickel which has previously been used in magnetoelastic sensors. In the present composite material axial magnetic induction sensitivities of 32 μ T/Nm and tangential field sensitivities of 12 A/Nm2 (=15 μT/Nm) were obtained, which were 50% better than nickel. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.365561
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  • 14
    Electronic Resource
    Electronic Resource
    Misoprostol in the treatment of chronic refractory constipation: results of a long-term open label trial (1997)
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 11 (1997), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Misoprostol is known to be effective in stimulating intestinal transit both in healthy individuals and in patients with chronic constipation when evaluated in short-term trials. The aim of this study was to determine the utility of misoprostol in the long-term management of patients with chronic refractory constipation.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:Eighteen patients were offered misoprostol (600–2400 μg/day) as adjunctive therapy in an open-ended, non-blinded trial. All patients were encouraged to continue the drug for a minimum of 4 weeks, after which time the effect on bowel movement patterns was evaluated and continued use of misoprostol was offered to those patients who demonstrated a clinical benefit.〈section xml:id="abs1-3"〉〈title type="main"〉Results:Six patients withdrew prior to 4 weeks because of side-effects. In the 12 patients who continued the treatment and were evaluated at 4 weeks, the mean interval between bowel movement frequency had decreased from a baseline of 11.25 to 4.8 days (P=0.0004). Eight patients continued the long-term treatment, with sustained response seen in six. In a subset of patients (n=4) the effect of single-dose misoprostol (400 μg) was evaluated compared to healthy controls (n=5) on post-prandial segmental colonic motility. Misoprostol augmented the colonic motility response to a meal throughout the colon, and this was significantly greater in the left versus right colonic segments (P 〈 0.05).〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:Misoprostol can be effective as part of the long-term medical treatment of patients with chronic refractory constipation, but side-effects are observed at higher doses and can be a limiting factor. Part of misoprostol's action may be mediated through the augmentation of colonic motility, particularly of the left colon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.1997.00237.x
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  • 15
    Electronic Resource
    Electronic Resource
    Comparison of morning and evening administration of rabeprazole for gastro-oesophageal reflux and nocturnal gastric acid breakthrough in patients with reflux disease: a double-blind, cross-over study (2003)
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 18 (2003), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aim:  To assess the effect of timing of rebeprazole (RB) 20 mg/d administration on oesophageal acid exposure and nocturnal gastric acid breakthrough (NGAB) in patients with GERD.Methods:  20 GERD patients received two 7-day treatments of RB in the morning (a.m.) or in the evening (p.m.) hours. The regimens were randomized in a double-blind fashion and separated by a 7-day washout period. The tablets were taken 30 min before standardized meals. A combined (oesophageal & gastric) 24-hour pH monitoring was performed before and on day 7 of each treatment.Results:  Total oesophageal acid exposure was normalized in 10/14 (71.4%) patients with RB p.m. and in 6/15 (42.8%) with RB a.m. RB p.m. significantly decreased the nocturnal supine oesophageal acid exposure vs. RB a.m., 0.2% vs. 3.4%. The mean NGAB duration was significantly shortened with RB a.m. and p.m. vs. the baseline recording, 4.1±1.8 and 3.4±1.5 hours vs. 7.8±1.7 hours.Conclusions:  Rabeprazole significantly reduced the NGAB duration and significantly increased the mean nocturnal gastric pH; RB p.m. normalized more effectively the total oesophageal exposure than RB-a.m.; RB p.m. provided significantly better control of nocturnal supine gastro-oesophageal reflux than a.m. dosing. These data suggest that administration of a PPI before the evening meal maximizes acid control and would be the preferred dosing schedule in GERD patients, particularly those with nocturnal symptoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.2003.01776.x
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  • 16
    Electronic Resource
    Electronic Resource
    The effect of intravenous erythromycin on solid meal gastric emptying in patients with chronic symptomatic post-vagotomy–antrectomy gastroparesis (1997)
    Oxford BSL : Blackwell Science
    Alimentary pharmacology & therapeutics 11 (1997), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Chronic symptomatic gastroparesis occurs in 3–5% of patients following vagotomy and antrectomy. Erythromycin, a macrolide antibiotic, improves gastric emptying in patients with idiopathic and diabetic gastroparesis. Erythromycin's effect on gastric emptying in patients with post-vagotomy– antrectomy gastroparesis is unknown. The aim of this study was to determine if a single dose of intravenous erythromycin (1 mg/kg or 6 mg/kg) accelerates solid meal gastric emptying in patients with chronic symptomatic post-vagotomy–antrectomy gastroparesis. Methods: Six patients were entered into the study, three males and three females, with a mean age of 50 years. Four patients were randomized to receive erythromycin 6 mg/kg and two patients 1 mg/kg. The mean time since initial surgery was 9.2 years (range 1–16 years) with five patients having undergone a Roux-en-Y revision. Results: Intravenous erythromycin significantly lowered percentage gastric retention at 120 min, from a baseline of 90.5±6% (S.E.M.) to 40.1±4.8% after erythromycin (P=0.0002). Erythromycin improved gastric emptying in each patient by at least 40%. Intravenous erythromycin significantly accelerated the rate of gastric emptying in the first 30 min after meal ingestion from a baseline rate of 0.072±0.06%/min to 0.96±0.31%/min after erythromycin (P=0.028). For each of the subsequent 30 minute time periods, erythromycin had no significant effect on the rate of gastric emptying. Conclusion: Intravenous erythromycin significantly improves the initial phase of solid meal gastric emptying in patients with chronic symptomatic post-antrectomy–vagotomy gastroparesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.1997.148324000.x
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  • 17
    Electronic Resource
    Electronic Resource
    Laparoscopic percutaneous jejunostomy for long term enteral access (1996)
    Springer
    Surgical endoscopy and other interventional techniques 10 (1996), S. 1008-1011 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopy — Jejunostomy — Enteral access
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Patients suffering from upper gastrointestinal pathology may require jejunal feeding for adequate nutrition. A laparoscopically guided percutaneous jejunostomy offers a minimally invasive means of obtaining such feeding access. Methods: Laparoscopic jejunostomy was performed in 32 patients. The most common indications were gastroparesis (n= 16), neurological deficits (n= 7), and proximal obstruction (n= 5). The proximal jejunum was affixed to the abdominal wall using intracorporeal and extracorporeal transabdominal sutures, allowing safe insertion of an 18-Fr Silastic dual-lumen tube. Results: Laparoscopic jejunostomy was successfully completed for 28 patients; the procedure was converted to an open operation in four cases. Three of these four were among 14 patients undergoing the procedure who had a history of previous abdominal surgery. Major complications were observed in seven patients, including one reoperation and one death from aspiration pneumonia. Tube feeding was accomplished in all patients; progression to full enteral feeding proceeded without interruption in 20 patients. Conclusion: Laparoscopic jejunostomy can be performed with relative safety. Morbidity, though high, is usually related to preexisting disease. Previous abdominal surgery is not necessarily a contraindication to laparoscopic jejunostomy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900225
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  • 18
    Electronic Resource
    Electronic Resource
    Analysis of deformed YBa2Cu3O7−δ (1990)
    Springer
    Journal of materials science 25 (1990), S. 1978-1986 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this study, polycrystalline YBa2Cu3O7−δ (123) was deformed under controlled conditions with a confining pressure of 1.0GPa, temperatures of 25, 500 and 800° C, and a strain rate of 10−4 sec−1 in order to ascertain the micromechanisms of deformation that give rise to the macroscopic plastic behaviour. The deformed material was analysed using optical microscopy, transmission electron microscopy (TEM), and a SQUID magnetometer to study the effects of deformation on the microstructure of YBa2Cu3O7−δ and how changes in the microstructure affected the superconducting properties. The results of these preliminary experiments suggest that the 123 material will be very difficult to deform plastically as slip occurs only on the (001) plane. The lack of multiple slip systems implies that this material will show some brittle behaviour up to a very high homologous temperature. Even when plastic behaviour can be sustained for high strains it may require high annealing temperatures to remove lattice imperfections which impede the superconducting currents. Densification by high pressure deformation may make reoxygenation difficult due to the reduced diffusion rates between the grains. These factors combined suggest that traditional fabrication techniques are not applicable to the 123 material. More work needs to be carried out to determine how annealing affects the microstructures of deformed materials and how these changes in microstructure affect the superconducting properties of these materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01045752
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  • 19
    Electronic Resource
    Electronic Resource
    Engineering magnetic nanocomposite microstructures (2000)
    Springer
    Journal of materials science 35 (2000), S. 3459-3466 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The realization of high energy densities in permanent magnetic materials requires careful control of both the composition and the processing conditions to develop appropriate microstructures. In this paper, we will show that manipulation of multiple alloying additions leads to the synthesis of magnetically optimum nanoscale metal matrix composite microstructures in a 9-element modified Nd-Fe-B alloy. The development of composite microstructures in hard magnetic materials is a novel concept resulting in many beneficial effects on the resulting structure/processing/property relationships.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004836807586
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  • 20
    Electronic Resource
    Electronic Resource
    Low-temperature magnetic properties of EuMo6S8 and EuMo6Se8 (1984)
    Springer
    Journal of low temperature physics 55 (1984), S. 111-125 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The low-temperature magnetic properties of EuMo6S8 and EuMo6Se8 have been investigated by means of the151Eu Mössbauer effect between 0.06 and 300 K and by measuring dc and ac magnetic susceptibilities between 0.017 and 3 K. A sharp deviation of the dc susceptibility from Curie-Weiss behavior indicates that EuMo6S8 and EuMo6Se8 order magnetically at 0.40 and 0.85 K, respectively. A drastic broadening of the Mössbauer linewidth of both compounds occurs at 0.9 K. The broadening above the magnetic ordering temperature for EuMo6S8 is explained in terms of slow relaxation effects arising from the depopulation of higher crystal field levels of Eu2+ ions. The combination of Mössbauer and susceptibility results indicates that the magnetically ordered states of EuMo6S8 and EuMo6Se8 are strongly affected by the crystal field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00683654
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