Reliability assessment of hyperspectral imaging with the HyperView™ system for lower extremity superficial tissue oxygenation in young healthy volunteers

Purpose: Hyperspectral imaging (HSI) is a noninvasive spectroscopy technique for determining superficial tissue oxygenation. The HyperView™ system is a hand-held camera that enables perfusion image acquisition. The evaluation of superficial tissue oxygenation is warranted in the evaluation of patients with peripheral arterial disease. The aim was to determine the reliability of repeated HSI measurements. Methods: In this prospective cohort study, HSI was performed on 50 healthy volunteers with a mean age of 26.4 ± 2.5 years, at the lower extremity. Two independent observers performed HSI during two subsequent measurement sessions. Short term test–retest reliability and intra- and inter-observer reliability were determined, and generalizability and decision studies were performed. Transcutaneous oxygen pressure (TcPo2) measurements were also performed. Results: The short term test–retest reliability was good for the HSI values determined at the lower extremity, ranging from 0.72 to 0.90. Intra- and inter-observer reliability determined at different days were poor to moderate for both HSI (0.24 to 0.71 and 0.30 to 0.58, respectively) and TcPo2 (0.54 and 0.56, and 0.51 and 0.31, respectively). Reliability can be increased to >0.75 by averaging two measurements on different days. Conclusion: This study showed good short term test–retest reliability for HSI measurements, however low intra- and inter-observer reliability was observed for tissue oxygenation measurements with both HSI and TcPo2 performed at separate days in young healthy volunteers. Reliability of HSI can be improved when determined as a mean of two measurements taken on different days.

Assessing the creep performance of full-scale bamboo scrimber columns

Bamboo scrimber is a kind of artificial processing material with high compressive strength, large size, natural texture, and wide application. It is made by rolling and de-fibering bamboo into a loose reticulate bundle, which is unbroken transversely, and loosely interlaced in the longitudinal direction, followed by drying, gluing, assembling, and hot pressing. In this study, to better understand the application value of bamboo scrimber in construction engineering, the performance of axially compressed solid columns that have been completed with three full-scale solid bamboo scrimber columns of 100 mm width, 100 mm height, and 2000 mm length were subjected to creep tests for 3 months. The specimens J1, J2, and J3 were designed to carry the long-term load of 0.2, 0.4, and 0.6 times the short-term test failure load of the same batch of specimens, respectively. The experimental study found that the bamboo scrimber columns could not bear 0.6 times of the short-term test failure load Pu, and that temperature and humidity greatly influenced creep of the specimens. Finally, a creep constitutive equation was established using a three-parameter model, and the equation matched well with the creep test data.

Short-Term Test–Retest Reliability of Contralateral Suppression of Click-Evoked Otoacoustic Emissions in Normal-Hearing Subjects

Purpose The objective of the current study was to investigate the short-term test–retest reliability of contralateral suppression (CS) of click-evoked otoacoustic emissions (CEOAEs) using commercially available otoacoustic emission equipment. Method Twenty-three young normal-hearing subjects were tested. An otoscopic evaluation, admittance measures, pure-tone audiometry, measurements of CEOAEs without and with contralateral acoustic stimulation (CAS) to determine CS were performed at baseline ( n = 23), an immediate retest without and with refitting of the probe (only CS of CEOAEs; n = 11), and a retest after 1 week ( n = 23) were performed. Test–retest reliability parameters were determined on CEOAE response amplitudes without and with CAS, and on raw and normalized CS indices between baseline and the other test moments. Results Repeated-measures analysis of variance indicated no random or systematic changes in CEOAE response amplitudes without and with CAS, and in raw and normalized CS indices between the test moments. Moderate-to-high intraclass correlation coefficients with mostly high significant between-subjects variability between baseline and each consecutive test moment were found for CEOAE response amplitude without and with CAS, and for the raw and normalized CS indices. Other reliability parameters deteriorated between CEOAE response amplitudes with CAS as compared to without CAS, between baseline and retest with probe refitting, and after 1 week, as well as for frequency-specific raw and normalized CS indices as compared to global CS indices. Conclusions There was considerable variability in raw and normalized CS indices as measured using CEOAEs with CAS using commercially available otoacoustic emission equipment. More research is needed to optimize the measurement of CS of CEOAEs and to reduce influencing factors, as well as to make generalization of test–retest reliability data possible.

REPRODUCIBILITY OF EUCAPNIC VOLUNTARY HYPERVENTILATION FOR EXERCISE-INDUCED BRONCHOSPASM DIAGNOSIS IN ASTHMATIC CHILDREN AND ADOLESCENTS.

BACKGROUND: Exercise-induced respiratory symptoms are frequently reported by asthmatics and exercise-induced bronchospasm (EIB) is a frequent cause that requires objective testing for diagnosis. Eucapnic voluntary hyperventilation (EVH) is recommended as an exercise surrogate stimulus for this purpose, but its short-term reproducibility is not yet established in young asthmatics. OBJECTIVE: To evaluate the short-term test-retest agreement and reproducibility of FEV1 changes after EVH in young asthmatics. METHODS: Asthmatics aged between 10 and 20 years underwent EVH for EIB diagnosis on two occasions 2-4 days apart at a specialized university clinic. FEV1 was measured 5, 15 and 30 minutes after EVH with a target ventilation rate 21 times baseline FEV1. EIB was diagnosed as a decrease >10% in FEV1 from baseline. RESULTS: Twenty-six of 62 recruited individuals tested positive for EIB on both visits (positive group) and 17 on one visit only (divergent group); and 19 tested negative on both visits (negative group). The overall agreement was 72.5% (95%CI 61.6%, 83.6%) and positive and negative agreement was 41.9% and 30.6% respectively. Despite overall low bias in FEV1 response between test days (0.87%), the limits of agreement were wide (+20.72%). There were no differences in pre-challenge FEV1 or achieved ventilation rate, between visits either between groups (p=0.097 and p=0.461) or within groups, (p=0.828 and p=0.780). No test was interrupted by symptoms and there were no safety issues. CONCLUSIONS: More than one EVH test should be performed in young asthmatics with a negative test to exclude EIB and minimize misdiagnosis and mistreatment.

Tracking System and Its Application in Unmanned Automobile Navigation Based on Sparse Photoelectric Sensor Network

Sensor tracking technology has broad prospects of application in the fields of smart home and environmental protection. The passive motion tracking method of sensor networks can realize the perception of location, temperature and other information without carrying sensor nodes. A sparse network tracking system based on infrared sensor nodes is proposed in this study, which can control the running automobiles with unmanned navigation. On the basis of the theory of diffraction, the way of spreading for wireless received signal strength (RSS) can be divided into "scattered waves" and "diffracted waves," which can be regarded as two components of infrared sensing wireless signals so as to further propose the RSS indicators of "long-term testing value" and "short-term test value." Based on these indicators, a measurement model based on diffraction effects and scattering effects is proposed, and an improved particle filter algorithm is used to update the motion tracking. The hardware design of each module in an unmanned vehicle includes the main controller, tracking circuit, serial port circuit, motor control circuit and infrared sensor control circuit of the car. In the experiment, the measurement accuracy of the tracking system based on the sparse infrared photoelectric sensor was first tested. In the simulation experiment, the long-term test value, the short-term test value and the actual measurement value were compared respectively. The test results show that the theoretical RSS value and the actual test result can be matched. Moreover, the infrared photoelectric tracking system is used to design the navigation control system of unmanned cars, helping the car to drive automatically through obstacle avoidance test and tracking obstacle avoidance test.