729 research outputs found
Biomimetic Micro Air Vehicle Testing Development and Small Scale Flapping-Wing Analysis
The purpose of this research was to develop testing methods capable of analyzing the performance of a miniature flapping-wing mechanism that can later be adapted to a biomimetic micro air vehicle (MAV). Three small scale flapping mechanisms capable of single plane flapping, flapping with active pitch control, and flapping/pitch with out-of-plane movement were designed using SolidWorks. The flapping-only model was fabricated on an Objet Eden 500V 3-dimensional printer. The flapping mechanism was mounted on an aluminum plate supported by air bearings, and thrust was measured for a variety of conditions. The testing was conducted using wings composed of carbon fiber and Mylar in four different size configurations, with flapping speeds ranging from 3.5 – 15 Hertz. The thrust was measured using an axially mounted 50 gram load cell which resulted in an accuracy of ± 0.1 gram. Non-dimensional thrust and power numbers were computed. The flapping mechanism was then mounted on a 6-component force balance to measure dynamic loading, which demonstrated the ability to gather time-accurate data within a single flapping stroke at speeds as high as 15 Hz. High speed cameras operated at 1500 Hz were also used for capturing images of the structure of the wing for various testing conditions. Overall this research successfully demonstrated both qualitative and quantitative testing procedures that can be utilized in developing small scale flapping-wing micro air vehicles
Fluorescence Lidar Multicolor Imaging of Vegetation
Multicolor imaging of vegetation fluorescence following laser excitation is reported for distances of 50 m. A mobile laser-radar system equipped with a Nd:YAG laser transmitter and a 40-cm-diameter telescope was utilized. The laser light was Raman shifted to 397 nm with pulse energies of approximately 30 mJ. An image-intensified CCD camera with a specially designed split-mirror Cassegrainian telescope was utilized for the simultaneous recording of fluorescence images of leaves and branches in four different spectral bands. Additionally, fluorescence spectra at selected points within the detection area were measured with an image-intensified diode array system. Image processing permits extraction of information related to the physiological status of the vegetation and might prove useful in forest decline research
Clinical spectral characterisation of colonic mucosal lesions using autofluorescence and delta aminolevulinic acid sensitisation
Background and aims-Laser induced fluorescence (LIF) from colonic mucosa was measured in vivo with and without delta aminolevulinic acid (ALA) in an attempt to differentiate between neoplasia and non-neoplasia in real time during colonoscopy. Methods-Spectra from 32 adenomas, 68 normal sites, and 14 hyperplastic polyps in 41 patients were obtained with a point monitoring system. Twenty one of the patients had been given a low dose of ALA as a photosensitiser before the examination. Light of 337, 405, or 436 nm wavelength was used as excitation. Stepwise multivariate Linear regression analysis was performed. Results-With 337 nm excitation, 100% sensitivity and 96% specificity was obtained between normal mucosa and adenomas. Seventy seven per cent of the hyperplastic polyps were classified as non-neoplastic. When exciting with 405 and 436 nm, the possibility of distinguishing different types of tissue was considerably better in the ALA patients than in the non-ALA patients. Conclusions-The in vivo point measurements imply that a good discrimination between normal tissue and adenomatous polyps can be obtained using the LIF technique. Excitation at 337 nm and at 405 nm or 436 nm using ALA gives good results. LIF also shows potential for distinguishing adenomatous from hyperplastic polyps. The number of detection wavelengths could be reduced if chosen properly
Remote monitoring of Vegetation using a Fluorescence LIDAR System in Spectrally Resolving and Multi-spectral Imaging Modes
Physical demand but not dexterity is associated with motor flexibility during rapid reaching in healthy young adults
Healthy humans are able to place light and heavy objects in small and large target locations with remarkable accuracy. Here we examine how dexterity demand and physical demand affect flexibility in joint coordination and end-effector kinematics when healthy young adults perform an upper extremity reaching task. We manipulated dexterity demand by changing target size and physical demand by increasing external resistance to reaching. Uncontrolled manifold analysis was used to decompose variability in joint coordination patterns into variability stabilizing the end-effector and variability de-stabilizing the end-effector during reaching. Our results demonstrate a proportional increase in stabilizing and de-stabilizing variability without a change in the ratio of the two variability components as physical demands increase. We interpret this finding in the context of previous studies showing that sensorimotor noise increases with increasing physical demands. We propose that the larger de-stabilizing variability as a function of physical demand originated from larger sensorimotor noise in the neuromuscular system. The larger stabilizing variability with larger physical demands is a strategy employed by the neuromuscular system to counter the de-stabilizing variability so that performance stability is maintained. Our findings have practical implications for improving the effectiveness of movement therapy in a wide range of patient groups, maintaining upper extremity function in old adults, and for maximizing athletic performance
Laser-induced fluorescence studies of the biodistribution of carotenoporphyrins in mice.
The biodistribution of two recently developed tumour markers, trimethylated (CP(Me)3) and trimethoxylated (CP(OMe)3) carotenoporphyrin, was investigated by means of laser-induced fluorescence (LIF) after i.v. injection into 38 tumour-bearing (MS-2 fibrosarcoma) female Balb/c mice. At 3, 24, 48 or 96 h after administration, the carotenoporphyrin fluorescence was measured in tumoral and peritumoral tissue, as well as in the abdominal, thoracic and cranial cavities. The fluorescence was induced by a nitrogen laser-pumped dye laser, emitting light at 425 nm, and analysed by a polychromator equipped with an image-intensified CCD camera. The fluorescence was evaluated at 490, 655 and 720 nm: the second and third wavelengths represent the carotenoporphyrin (CP)-related peaks, whereas the first one is close to the peak of the tissue autofluorescence. The tumour and the liver were the two tissue types showing the strongest carotenoporphyrin-related fluorescence, whereas the cerebral cortex and muscle consistently exhibited weak substance-related fluorescence. In most tissue types, the fluorescence intensities decreased over time. A few exceptions were observed, notably the liver, in which the intensity remained remarkably constant over the time period investigated
The L3Pilot Common Data Format - Enabling Efficient Automated Driving Data Analysis
Analyzing road-test data is important for developing automated vehicles. L3Pilot is a European pilot project on level 3 automation, including 34 partners among manufacturers, suppliers and research institutions. Targeting around 100 cars and 1000 test subjects, the project will generate large amounts of data. We present a data format, allowing efficient data collection, handling and analysis by multiple organizations. A project of the scope of L3Pilot involves various challenges. Data come from a multitude of heterogeneous sources and are processed by a variety of tools. Recorded data span all data types generated in various vehicular sensors/systems and are enriched with external data sources. Videos supplement time-series data as external files.
Derived measures and performance indicators \u2013 required to answer research questions about effectiveness of automated driving \u2013 are processed by analysis partners and included for each test session. As a file format, we chose HDF5, which offers a data model and software libraries for storing and managing data. HDF5 is designed for flexible and efficient I/O and for high volume and complex data. The usage of different computing environments for specific tasks is facilitated by the portability that comes with the format. Portability is also important for exploiting the rising potential within artificial intelligence (e.g. automatic scene detection and video annotation). Based on lessons learned from past field tests, we defined a general frame for the common data format that is aligned with the data processing steps of FESTA \u201cV\u201d evaluation methodology. The definitions include representation of the source signals and a hierarchical structure for including multiple datasets that are gradually supplemented (post-processed or annotated) during the various analysis steps. By using the HDF5 format, analysis partners have the freedom to exploit their familiar tools: MATLAB, Java, Python, R, etc. First comparisons between time-series data in previous projects (e.g. AdaptIVe) and the proposed data format show a reduction in storage size of around 80 %, without losses in performance. Much of that is due to efficient internal compression and structuring of data. Considering the amount of objective data involved in automated driving, this leads to a great benefit, in terms of usability. This paper presents a compact, portable, and extensible format aimed at handling extremely large amounts of field test data collected in automated driving pilots. As a harmonized format between tens of organizations performing tests in the L3Pilot project, the proposed format has the potential to promote data sharing as well as development of common tools and gain popularity for use in other projects. The format is designed to allow efficient storing of data and its iterative processing with analysis and evaluation tools. The format also considers the requirements of AI tools supporting neural network training and use
Laser-induced fluorescence in malignant and normal tissue in mice injected with two different carotenoporphyrins.
Laser-induced fluorescence (LIF) was used to characterise the localisation of an intravenously administered trimethylated carotenoporphyrin [CP(Me)3] and a trimethoxylated carotenoporphyrin [CP(OMe)3] in an intramuscularly transplanted malignant tumour (MS-2 fibrosarcoma) and healthy muscle in female Balb/c mice, 3, 24, 48 and 96 h post injection. The fluorescence was induced with a dye laser pumped by a nitrogen laser, emitting light at 425 nm. The fluorescence spectra were recorded in the region 455-760 nm using a polychromator equipped with an image-intensified CCD camera. The tumour/peritumoral muscle ratio was about 5:1 for CP(Me)3 and about 6:1 for CP(OMe)3 in terms of the background-free fluorescence intensity, which peaked at about 655 nm. By including the endogenous tissue fluorescence, the contrast was further enhanced by a factor of approximately 2
Fluoridated elastomers: Effect on the microbiology of plaque
The objective of this study was to investigate the effect of fluoridated elastomeric ligatures on the microbiology of local dental plaque in vivo. This randomized, prospective, longitudinal, clinical trial had a split-mouth crossover design. The subjects were 30 patients at the beginning of their treatment with fixed orthodontic appliances in the orthodontic departments of the Liverpool and the Sheffield dental hospitals in the United Kingdom. The study consisted of 2 experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly allocated at the first visit to be placed around brackets on tooth numbers 12, 11, 33 or 22, 21, 43. Nonfluoridated elastomers were placed on the contralateral teeth. Standard nonantibacterial fluoridated toothpaste and mouthwash were supplied. After 6 weeks (visit 2), the elastomers were removed, placed in transport media, and plated on agar within 2 hours. Nonfluoridated elastomers were placed on all brackets for 1 visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the teeth contralateral to those that received them at visit 1. At visit 4, the procedures at visit 2 were repeated. Samples were collected on visits 2 and 4. A logistic regression was performed, with the presence or absence of streptococcal or anaerobic growth as the dependent variable. A mixed-effects analysis of variance was carried out with the percentage of streptococcal or anaerobic bacterial count as the dependent variable. The only significant independent variables were the subject variable (P = < .001) for the percentage of streptococcal and anaerobic bacterial count and the visit variable for the percentage of streptococcal count (P = < .001). The use of fluoridated or nonfluoridated elastomers was not significant for percentage of either streptococcal (P = .288) or anaerobic count (P = .230). Fluoridated elastomers are not effective at reducing local streptococcal or anaerobic bacterial growth after a clinically relevant time in the mouth
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