Dynamic strain measurement using piezoelectric polymer film

Piezoelectric polymers have been used to form the basis of dynamic strain gauges for the detection of stress waves. The linearity of response was tested using a split Hopkinson pressure bar arrangement. The results obtained illustrate the effectiveness of piezoelectric film strain gauges in the measurement of axial stress waves.

Determination of the force constant of a single-beam gradient trap by measurement of backscattered light

A single-beam gradient trap could potentially be used to hold a stylus for scanning force microscopy. With a view to development of this technique, we modeled the optical trap as a harmonic oscillator and therefore characterized it by its force constant. We measured force constants and resonant frequencies for 1-4-mu m-diameter polystyrene spheres in a single-beam gradient trap using measurements of back-scattered light. Force constants were determined with both Gaussian and doughnut laser modes, with powers of 3 and 1 mW, respectively. Typical values for spring constants were measured to be between 10(-6) and 4 x 10(-6) N/m. The resonant frequencies of trapped particles were measured to be between 1 and 10 kHz, and the rms amplitudes of oscillations were estimated to be around 40 nm. Our results confirm that the use of the doughnut mode for single-beam trapping is more efficient in the axial direction. (C) 1996 Optical Society of America.

Effect of the bilateral hip bone density measurement on clinical practice in elderly subjects

Objectives: The aim of this study was to determine whether the addition of the measurement of bilateral hip bone mineral density (BMD) has an impact on indications for osteoporosis (OP) treatment in community-dwelling elderly individuals, based on criteria from the National Osteoporosis Foundation (NOF). Methods: In total, 605 consecutive community-dwelling elderly individuals who were 65 years and older were evaluated. Dual energy X-ray absorptiometry was used to determine the lowest T-score in the lumbar spine + unilateral hip, the bilateral hips, and the lumbar spine + bilateral hips. Risk factors associated with the lowest T-score in these three conditions were applied to indicate treatment in accordance with NOF criteria. McNemar`s test was used to assess the difference of adding bilateral hip BMD measurements. Results: There was a significant difference in the frequency of pharmacological indication using NOF criteria together with the lowest T-score for the three tests (72.8% for lumbar spine + bilateral hips and 71.2% for lumbar spine + unilateral hip; p=0.002). A higher frequency of treatment indication was also observed for lumbar spine + unilateral hip (71.2%) compared to bilateral hips (61.1%) (p<0.001). The discrepancies in treatment appeared to be more evident in women when analyzed by gender distribution. Conclusion: Our finding supports the theory that evaluation of the bilateral hips with the lumbar spine seems to be more sensitive measure for identifying patients with an osteoporosis treatment indication. Furthermore, despite the well-known artifact in the lumbar spine, this site should not be excluded when determining the indication for OP treatment in elderly people. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Direct measurement of pulse distortion near the zero-dispersion wavelength in an optical fiber by frequency-resolved optical gating

The technique of frequency-resolved optical gating is used to characterize the intensity and the phase of picosecond pulses after propagation through 700 m of fiber at close to the zero-dispersion wavelength. Using the frequency-resolved optical gating technique, we directly measure the severe temporal distortion resulting from the interplay between self-phase modulation and higher-order dispersion in this regime. The measured intensity and phase of the pulses after propagation are found to be in good agreement with the predictions of numerical simulations with the nonlinear Schrodinger equation. (C) 1997 Optical Society of America.

Measurement of total phospholipids in urine of patients treated with gentamicin

Aims The excretion of phospholipids in urine may be a marker of the early renal toxicity of the aminoglycoside antibiotics. Urinary phospholipids are formed in myeloid bodies which develop in the lysosomes of proximal tubules during treatment with the aminoglycosides, and overflow into the urine. Methods Published assays were modified in order to measure the total phospholipid concentrations in human urine. Phospholipids were extracted from freeze-dried urine samples, digested in concentrated sulphuric acid, and the inorganic phosphorus content determined by complexing with ammonium molybdate and measuring the absorbance at 820 nm. Ten septicaemic patients treated with gentamicin for 5-7 days had significantly higher urine phospholipid concentrations than 10 healthy untreated control subjects (P<0.0001). There was a negative Linear relationship between phospholipid excretion and creatinine clearance (r(2) = 0.71). Results In 34 patients with acute pyelonephritis, increased phospholipid concentrations were observed prior to treatment compared with healthy controls (P<0.001) and did not alter during treatment with gentamicin. However, the phospholipid concentrations decreased significantly after treatment was completed (P<0.03). Conclusions These studies suggest that urinary phospholipids may indicate early aminoglycoside toxicity but with poor specificity, as many of the infections being treated may themselves be associated with phospholipiduria.

On the distance between distinct group Latin squares

In an article in 1992, Drapal addressed the question of how far apart the multiplication tables of two groups can be? In this article we continue this investigation; in particular, we study the interaction between partial equalities in the multiplication tables of the two groups and their subgroup structure. (C) 1997 John Wiley & Sons, Inc.

Measurement of radiation dose received by the hands and thyroid of staff performing gridless fluoroscopic procedures in children

The aim of this study was to confirm that the radiation doses received by attendants who manually restrain infants during fluoroscopic procedures are low. Doses to the hands and neck of three radiologists and three nurses performing or assisting at all the fluoroscopic procedures in a children's hospital were measured for 1 month using thermoluminescent dosemeters. All fluoroscopy on children at this hospital is performed without an antiscatter grid. Total doses for the neck ranged from 20 to 50 mu Sv per week and for hands from 40 to 210 mu Sv per week. These doses were shared by the three radiologists and the three nurses. Individual doses received per staff member are very small when compared with the doses received by interventional radiology staff. Doses received by staff in this study were of the order of 5% of the limit advised by the National Health and Medical Research Council of Australia (NHMRC) for radiation workers. Nurses received larger doses than radiologists and steps will be taken to reduce this dose further.

Estimating correlations from epidemiological data in the presence of measurement error

Analysis of a major multi-site epidemiologic study of heart disease has required estimation of the pairwise correlation of several measurements across sub-populations. Because the measurements from each sub-population were subject to sampling variability, the Pearson product moment estimator of these correlations produces biased estimates. This paper proposes a model that takes into account within and between sub-population variation, provides algorithms for obtaining maximum likelihood estimates of these correlations and discusses several approaches for obtaining interval estimates. (C) 1997 by John Wiley & Sons, Ltd.

Three-dimensional sonographic measurement of contralateral lung volume in fetuses with isolated congenital diaphragmatic hernia

Purpose. To use 3-dimensional sonography (3DUS) to measure contralateral lung volume and evaluate the potential of this measurement to predict neonatal outcome in isolated congenital diaphragmatic hernia (CDH). Methods. Between January 2002 and December 2004, the contralateral lung volumes of 39 fetuses with isolated CDH were measured via 3DUS using rotational multiplanar imaging. The observed/expected contralateral fetal lung volume ratios (o/eContFLVR) were compared with the lung/head ratio (LHR), observed/expected total fetal lung volume ratio (o/e-TotFLVR), and postnatal outcome. Results. Contralateral lung volumes are less reduced than total lung volumes in CDH. The bias and precision of 3DUS in estimating contralateral lung volumes were 0.99 cm(3) and 1.11 cm(3), respectively, with absolute limits of agreement ranging from -1.19 cm(3) to + 3.17 cm(3). The o/e-ContFLVR was significantly lower in neonatal death cases (median, 0.49 cm(3); range, 0.22-0.99 cm(3)) than in survival cases (median, 0.58 cm(3); range, 0.42-0.92 cm(3) [p < 0.011). Overall accuracy of the o/e-ContFLVR, o/e-TotFLVR, and LHR in predicting neonatal death were 67.7% (21/31), 80.7% (25/31), and 77.4% (24/31), respectively. Conclusion. Although o/e-ContFLVR can be precisely measured with 3DUS and can be used to predict neonatal death in CDH, it is less accurate than LHR and o/e-TotFLVR for that purpose. (C) 2007 Wiley Periodicals, Inc.

Profiles of functional deficits in mild cognitive impairment and dementia: benefits from objective measurement

The magnitude Of functional impairment that may indicate the threshold between MCI and incipient Alzheimer`s disease (AD) has not been clearly defined. The objective was to examine the pattern of functional impairment in the continuum MCI-AD. Eighty-nine older adults (32 cognitively unimpaired, 31 MCI, and 26 AD patients) were examined with the Brazilian version of the Direct Assessment of Functional Status (DAFS-BR) at a University-based memory clinic. MCI patients were sub-divided according to the progression to AD upon follow-up, and had baseline cognitive, functional and biological variables analyzed. MCI patients displayed mild deficits in functional abilities, with intermediate scores as compared to controls and AD. The DAFS-BR items that differentiated MCI from controls involved the ability to deal with finances and shopping skills. At baseline, scores obtained by MCI patients who converted to AD were not significantly different from scores of nonconverters. The magnitude of functional deficits was associated with AD-like pathological findings in the CSF. In conclusion, MCI patients present with early functional changes in complex, instrumental abilities that require the integrity of memory and executive functions. The objective measurement of the functional state may help identify older adults with increased risk of developing dementia in the MCI-AD continuum. (JINS, 2010, 16, 297-305.)

Inter- and intra-tester reliability of clinical measurement to determine medio-lateral patellar position using a pachymeter or visual assessment

The aim was to investigate inter-tester and intra-tester reliability and parallel reliability between a visual assessment method and a method using a pachymeter for locating the mid-point of the patella in determining the medial/lateral patella orientation. Fifteen asymptomatic subjects were assessed and the mid-point of the patella was determined by both methods on two separate occasions two weeks apart. Inter-tester reliability was obtained by ANOVA and by intraclass correlation coefficient (ICC); intra-tester reliability was obtained by a paired t-test and ICC; and parallel reliability was obtained by Pearson`s Correlation and ICC, for the measurement on the first and second evaluations. There was acceptable inter-tester agreement (p = 0.490) and reliability for the visual inspection (ICC = 0.747) and for the pachymeter (ICC = 0.716) at the second evaluation. The inter-tester reliability in the first evaluation was unacceptable (visual ICC = 0.604; pachymeter ICC = 0.612). Although there was statistical similarity between measurements for the first and second evaluations for all testers, intra-tester reliability was not acceptable for both methods: visual (examiner 1 ICC = 0.175; examiner 2 ICC = 0.189; examiner 3 ICC = 0.155) and pachymeter (examiner 1 ICC = 0.214; examiner 2 ICC = 0.246; examiner 3 ICC = 0.069). Parallel reliability gave a perfect correlation at the first evaluation (r=0.828; p<0.001) and at the second (r=0.756; p<0.001) and reliability was between acceptable and very good (ICC = [0.748-0.813]). Both visual and pachymeter methods provide reliable and similar medial/lateral patella orientation and are reliable between different examiners, but the results between the two assessments at 2 weeks` interval demonstrated an unacceptable reliability. (C) 2009 Elsevier B.V. All rights reserved.