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  • 1
    ISSN: 1433-2965
    Keywords: Key words:Hip fracture – Osteoporosis – Precision – Ultrasound attenuation – Ultrasound velocity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: Quantitative ultrasound (QUS) is now accepted as a useful tool in the management of osteoporosis. There are a variety of QUS devices clinically available with a number of differences among them, including their coupling methods, parameter calculation algorithms and sites of measurement. This study evaluated the abilities of six calcaneal QUS devices to discriminate between normal and hip-fractured subjects compared with the established method of dual-energy X-ray absorptiometry (DXA). The short-term and mid-term precisions of these devices were also determined. Thirty-five women (mean age 74.5 ± 7.9 years) who had sustained a hip fracture within the past 3 years, and 35 age-matched controls (75.8 ± 5.6 years) were recruited. Ultrasound measurements were acquired using six ultrasound devices: three gel-coupled and three water-coupled devices. Bone mineral density was measured at the hip using DXA. Discrimination of fracture patients versus controls was assessed using logistic regression analysis (expressed as age- and BMI-adjusted odds ratios per standard deviation decrease with 95% confidence interval) and receiver operating characteristics (ROC) curve analysis. Measurement precision was standardized to the biological range (sCV). The sCV ranged from 3.14% to 5.5% for speed of sound (SOS) and from 2.45% to 6.01% for broadband ultrasound attenuation (BUA). The standardized medium-term precision ranged from 4.33% to 8.43% for SOS and from 2.77% to 6.91% for BUA. The pairwise Pearson correlation coefficients between different devices was highly significant (SOS, r= 0.79–0.93; BUA, r= 0.71–0.92). QUS variables correlated weakly, though significantly, with femoral BMD (SOS, r= 0.30–0.55; BUA, r= 0.35–0.61). The absolute BUA and SOS values varied among devices. The gel-coupled devices generally had a higher SOS than water-coupled devices. Bone mineral density (BMD) and BUA were weakly correlated with weight (r= 0.48–0.57 for BMD and r= 0.18–0.54 for BUA), whereas SOS was independent of weight. All the QUS devices gave similar, statistically significant hip fracture discrimination for both SOS and BUA measures. The odds ratios for SOS (2.1–2.8) and BUA (2.4–3.4) were comparable to those for femoral BMD (2.6–3.5), as were the area under the curve (SOS, 0.65–0.71; BUA, 0.62–0.71; BMD, 0.65–0.74) from ROC analysis. Within the limitation of the sample size all devices show similar diagnostic sensitivity.
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  • 2
    ISSN: 1433-2965
    Keywords: Key words:Bone density – Hip fracture – Osteoporosis – Quantitative ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: The incidence of osteoporotic hip fracture increases in postmenopausal women with low hip bone mineral density (BMD). Dual X-ray absorptiometry (DXA) is the most commonly used technique for the assessment of bone status and provides good measurement precision. However, DXA affords little information about bone architecture. Quantitative ultrasound (QUS) systems have been developed to evaluate bone status for assessment of fracture risk. Our study was designed to assess a new QUS system from Hologic, the Sahara; to compare it with a previous model, the Walker-Sonix UBA 575+; and to investigate whether it is able to discriminate between women with and without fracture. Using both ultrasound devices, the measurements were performed at the heels of 33 postmenopausal women who had recently sustained hip fracture. A control group of 35 age-matched postmenopausal women was recruited for comparison. The total, neck and trochanter femoral BMD values were assessed using DXA for both groups. QUS and DXA measurements were significantly lower in fractured patients (p〈0.005) than in the control group. The short-term, mid-term and standardized short-term precisions were used to evaluate the reproducibility of the two QUS systems. The Sahara showed a better standardized coefficient of variation for broadband ultrasound attenuation (BUA) than did the UBA 575+ (p〈0.001). The correlation of BUA and speed of sound (SOS) between the two QUS devices was highly significant, with an r value of 0.92 for BUA and 0.91 for SOS. However, the correlation between DXA and ultrasound parameters ranged from 0.28 to 0.44. We found that ultrasound measurements at the heel were significant discriminators of hip fractures with odds ratios (OR) ranging from 2.7 to 3.2. Even after adjusting the logistic regressions for total, neck or trochanter femoral BMD, QUS variables were still significant independent discriminators of hip fracture. The areas under the ROC curves of each ultrasound parameter ranged from 0.75 to 0.78, and compared very well with femoral neck BMD (p〉0.05). In conclusion, our study indicated that the calcaneal QUS variables, as measured by the Sahara system can discriminate hip fracture patients equally as well as hip DXA.
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  • 3
    ISSN: 1432-0649
    Keywords: PACS: 33.20.-t; 42.62.Fi; 42.65.Yj
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Optical parametric oscillator (OPO) and amplifier (OPA) devices are useful for spectroscopic sensing of chemical processes in laboratory, industrial, and environmental settings. This is particularly true of nanosecond-pulsed, continuously tunable OPO/OPA systems, for which we survey a variety of instrumental strategies, together with actual spectroscopic measurements. The relative merits of OPO wavelength control by intracavity gratings and by injection seeding are considered. A major innovation comprises an OPO with a ring cavity based on periodically poled lithium niobate (PPLN) and injection-seeded by a single-mode tunable diode laser (TDL). Active cavity control by an ‘intensity dip’ method yields an optical bandwidth ≤0.005 cm-1 (150 MHz), which compares favourably with the performance of advanced grating-tuned OPO/OPA systems. A novel adaptation of this TDL-seeded PPLN OPO employs a compact, inexpensive multimode pump laser, with which it is still possible to obtain continuously tunable single-mode signal output. Cavity ringdown (CRD) spectroscopy also figures prominently, with infrared (IR) CRD spectra from both grating-scanned and TDL-seeded OPOs reported. Finally, a tunable ultraviolet (UV) source, combining a TDL-seeded passive-cavity OPO and a sum-frequency generation stage, is developed for measurements of time-resolved IR-UV double resonance spectra of acetylene and UV laser-induced fluorescence spectra of nitric oxide.
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  • 4
    Electronic Resource
    Electronic Resource
    Melbourne, Australia : Blackwell Science Pty
    Nephrology 5 (2000), S. 0 
    ISSN: 1440-1797
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Mice with constitutive transgenic (tg) expression of interleukin-4 (IL-4) develop autoimmune-type disorders resembling lupus nephritis. The kidneys show progressive glomerulosclerosis with immunoglobulin (Ig) and complement deposition.Methods This study investigated the role of renal IL-4 expression and the relevance of glomerular Ig deposition in the pathogenesis of glomerulosclerosis in IL-4tg mice. The mice were treated with either IL-4 neutralizing antibody or the glucocorticoid methylprednisolone (MP). To further clarify whether the renal lesions were exclusively immune-mediated, IL-4tg mice were cross-bred with δ chain deficient mice (δ MT-/-), which are unable to produce Igs.Results Glomeruli of anti-IL-4-treated tg mice showed a normal structure with negligible Ig deposits. Similarly, in MP-treated tg mice only trace amounts of glomerular Ig deposits could be detected, although in comparison with wt mice, increased mesangial collagen deposition was evident. Despite complete absence of renal Ig deposits, IL-4tg/δMT-/- mice developed progressive glomerulosclerosis with mesangial accumulation of collagen types I, IV and V. Renal IL-4 expression was observed in both anti-IL-4- and MP-treated IL-4 tg mice, as well as in IL-4tg/δMT-/- mice. There was no statistically significant difference in the number of glomerular T cells and macrophages between the groups.Conclusions Our data demonstrate that in this model glomerulosclerosis developed independently of and prior to Ig deposition, and imply that the initial accumulation of glomerular extracellular matrix was due to renal IL-4 expression.
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  • 5
    Electronic Resource
    Electronic Resource
    Melbourne, Australia : Blackwell Science Pty
    Nephrology 5 (2000), S. 0 
    ISSN: 1440-1797
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Mice with constitutive transgenic (tg) expression of interleukin-4 (IL-4) develop autoimmune-type disorders resembling lupus nephritis. The kidneys show progressive glomerulosclerosis with immunoglobulin (Ig) and complement deposition.Methods This study investigated the role of renal IL-4 expression and the relevance of glomerular Ig deposition in the pathogenesis of glomerulosclerosis in IL-4tg mice. The mice were treated with either IL-4 neutralizing antibody or the glucocorticoid methylprednisolone (MP). To further clarify whether the renal lesions were exclusively immune-mediated, IL-4tg mice were cross-bred with δ chain deficient mice (δ MT-/-), which are unable to produce Igs.Results Glomeruli of anti-IL-4-treated tg mice showed a normal structure with negligible Ig deposits. Similarly, in MP-treated tg mice only trace amounts of glomerular Ig deposits could be detected, although in comparison with wt mice, increased mesangial collagen deposition was evident. Despite complete absence of renal Ig deposits, IL-4tg/δMT-/- mice developed progressive glomerulosclerosis with mesangial accumulation of collagen types I, IV and V. Renal IL-4 expression was observed in both anti-IL-4- and MP-treated IL-4 tg mice, as well as in IL-4tg/δMT-/- mice. There was no statistically significant difference in the number of glomerular T cells and macrophages between the groups.Conclusions Our data demonstrate that in this model glomerulosclerosis developed independently of and prior to Ig deposition, and imply that the initial accumulation of glomerular extracellular matrix was due to renal IL-4 expression.
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  • 6
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The most important product of the sequencing of a genome is a complete, accurate catalogue of genes and their products, primarily messenger RNA transcripts and their cognate proteins. Such a catalogue cannot be constructed by computational annotation alone; it requires experimental validation on a ...
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  • 7
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A facile tool is suggested for cutting the protruding flange of photoresist (PR) along the edge of a small substrate surface, which is caused by the spin-coating process in lithography. When the dimension of the substrate reduces to a few millimeters, the edge problem of PR cannot be ignored. Since the PR's thickness along the edge of the sample is much larger than that in the middle, a traditional double exposure method does not work well. The cutter proposed here consists of a blade and a sample holder, which are installed in a base. By adjusting the blade at a suitable dip angle and pushing it to the flange of PR along the edge of substrate fixed by the sample holder, the flange of PR of small samples will be eliminated completely with great ease. © 2002 American Institute of Physics.
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 1585-1586 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have proposed a new method that could increase the pulling stroke length in a thermal expansion pulling device used for crystal growth. In this method, the thermal expansion part consists of more than one expansion rod linked by materials with low thermal expansion coefficients. We have constructed an experimental setup to demonstrate the advantage of the new design over the previous one. The measured data showed that the stroke length can be increased by 40% with two expansion rods. Also, a linear temperature dependence of the length was observed, and the reason for this observation was discussed. © 2001 American Institute of Physics.
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  • 9
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Momentum profiles of the valence orbitals of methylpropane, also known as isobutane (CH3CH(CH3)CH3), have been studied by using a high resolution binary (e,2e) electron momentum spectrometer (EMS), at an impact energy of 1200 eV plus the binding energy, and using symmetric noncoplanar kinematics. The coincidence energy resolution of the EMS spectrometer is 0.95 eV full width at half-maximum. The experimental momentum profiles of the valence orbitals are compared with the theoretical momentum distributions calculated using Hartree–Fock (HF) and density functional theory (DFT) methods with the two basis sets of 6-31G and 6-311++G**. The B3LYP functionals are used for the DFT calculations. In general, the experimental momentum distributions are well described by the HF and DFT calculations. The pole strengths of the main ionization peaks from the orbitals in the inner valence are estimated. © 2001 American Institute of Physics.
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  • 10
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have designed and implemented a vertical cavity violet light emitting diode which features an optical resonator composed of an in situ grown GaN/AlGaN DBR and a high reflectivity dielectric mirror. The active InGaN MQW medium is grown directly atop the AlGaN DBR and the structure includes an intracavity lateral current spreading layer based on a p++/n++ InGaN/GaN tunnel junction. Electroluminescence shows directional emission, with modal linewidths as narrow as 0.6 nm. © 2001 American Institute of Physics.
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