63 research outputs found
The detection of wound infection by ion mobility chemical analysis
Surgical site infection represents a large burden of care in the National Health Service. Current methods for diagnosis include a subjective clinical assessment and wound swab culture that may take several days to return a result. Both techniques are potentially unreliable and result in delays in using targeted antibiotics. Volatile organic compounds (VOCs) are produced by micro-organisms such as those present in an infected wound. This study describes the use of a device to differentiate VOCs produced by an infected wound vs. colonised wound. Malodourous wound dressings were collected from patients, these were a mix of post-operative wounds and vascular leg ulcers. Wound microbiology swabs were taken and antibiotics commenced as clinically appropriate. A control group of soiled, but not malodorous wound dressings were collected from patients who had a split skin graft (SSG) donor site. The analyser used was a G.A.S. GC-IMS. The results from the samples had a sensitivity of 100% and a specificity of 88%, with a positive predictive value of 90%. An area under the curve (AUC) of 91% demonstrates an excellent ability to discriminate those with an infected wound from those without. VOC detection using GC-IMS has the potential to serve as a diagnostic tool for the differentiation of infected and non-infected wounds and facilitate the treatment of wound infections that is cost effective, non-invasive, acceptable to patients, portable, and reliable
Determination of Mealiness in Apples using Ultrasonic Measurements
A system based on ultrasonic energy absorbance was developed, for non-destructive measurements of three levels of texture degradation towards mealiness in Jonagold and Cox apples. The ultrasonic system comprises a high-power generator and a pair of 80 kHz ultrasonic transducers. One transducer, acting as a transmitter, sends a pulse through the apple tissue, which absorbs part of its energy, depending on internal textural attributes, and the transmitted pulse is received as an emerging signal by the other transducer. The detected ultrasound waves were analysed in parallel with the determination of the mealiness level of the fruit in accordance with destructive measurements in confined compression. The results obtained in Cox apples showed a good correlation between the ultrasound measurements and the confined-compression destructive tests for each mealiness level
Quality and Productivity Improvement of Wax Flowers
Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 9 (2007): Quality and Productivity Improvement of Wax Flowers. Manuscript CIOSTA 07 004. Vol. IX. December, 2007
Physiologia Plantarum
Abstract At the reproductive stage, lily plants bear two morphological types of mature leaves, one at the lower and one at the upper part of the stem. At the vegetative stage, all the leaves are similar to each other and to the reproductive plant's lower leaves. This heterophylly has not yet been explored. In this study, we show that it is not a result of the plant's age but rather an outcome of floral induction. The induction appears as an on-going process, during which the meristem still produces leaves but progressively becomes committed to reproduction. This intermediate period lasts until the ultimate switch to flower primordia occur. The leaves produced during floral induction, termed here as 'inductive', appear at the upper part of the stem. Besides their typical higher stomata density, these leaves have a poly-layered palisade mesophyll, whose cells exhibit a unique morphology and contain more chlorophyll than leaves of vegetative plants. These leaves display higher carbon assimilation, soluble sugars production and chloroplast-lipid accumulation. Accordingly, genes associated with stomata, chloroplast and photosynthesis are upregulated in these leaves. Our results were obtained when floral induction was achieved either by vernalization or photoperiod signals, ruling out a mere environmental effect. We suggest that lily plants prepares themselves for the high energy-demanding bloom by producing leaves with enhanced photosynthetic capacity, leading to an increase in soluble sugars. These novel findings introduce an adjacent affinity between photosynthesis and flowering and provide a non-destructive tool for identifying the plant's developmental stage ? vegetative or reproductive. This article is protected by copyright. All rights reserved
Robotic Detection of Disease Stress Using Hyperspectral Camera
Automatic early detection of anomalies in plant\u2019s status is crucial for advanced crops management and it became an important topic of multidisciplinary research in the last two decades. More recently, focused research has been addressed to plant\u2019s diseases detection, since the capability of detecting initial infection areas will enable to take targeted correction actions, permitting the potential reduction of pesticides or other input in agricultural systems, a more accurate control of condition of the crop, and eventually a final reduction in inputs costs.
In this work we explored the capabilities of automatic detection of disease symptoms in cucumber plants by means of a high resolution hyperspectral camera (400 nm \u2013 1000 nm) an integrated on a 6-DOF robotic manipulator.
Thanks to the precise motion control of the hyperspectral camera, the system allows to acquire a spectral hypercube, i.e. a 3D array containing VIS-NIR spectra (nominal resolution of 0.6 nm) of 2D imaged areas scanned while shifting the camera frontally to the target at a speed suitable to obtain the desired spatial resolution (in our case 0.3 mm/pix).
For the integration of the camera on the manipulator, a custom end-effector was designed, and a software tool was developed with Matlab to control the manipulator kinematics, the focusing of the camera and the acquisition (scan) of hypercubes. General aim of the implemented system was to obtain repeatable conditions during hypercube acquisitions in order to follow the disease symptoms evolution in the canopy, and to allow controlled multiple acquisitions from different view angles to the plant.
The study was conducted on cucumber plants exhibiting Powdery mildew fungal disease symptoms. From the hypercubes, a number of ROI corresponding to helathy and diesead portion of leaves were manually extracted with a custom software tool. The sub-hypercubes were processed at pixel level by applying Principal Component Analysis, Linear Discriminant Analysis, and a combinatorial selection of the most significant wavelengths in discriminating healthy tissue and symptoms. An additional approach based on a morphological analysis of the whole image at the selected wavelength was integrated to the spectral based classification. In particular, the morphological analysis was based on the evaluation of the variance of the spectral intensity in a fixed-sized window moving along the entire image.
Very promising results were obtained in terms of recognition of infected portions of leaves and for human machine interaction. As a preliminary results of the study, an average correct discrimination of 89% of pixels of the diseased areas was obtained. Furthermore the integration of the sensor and the manipulator control can be considered completed and ready for a full scale experiment
Synchronizing Geomagnetic Field Intensity Records in the Levant Between the 23rd and 15th Centuries BCE: Chronological and Methodological Implications
Abstract Archeomagnetic records are an important source of information on the past behavior of the geomagnetic field. Frequently, however, coeval archeomagnetic intensity (archeointensity) datasets from nearby locations display significant discrepancies, hampering precise reconstruction of highâresolution secular variation curve. This is the case for the time interval between the later phase of the Early Bronze and the early phase of the Late Bronze Ages (23rdâ15th centuries BCE) in the Levant and Mesopotamia. We address the problem by crossâcorrelating archeointensity datasets from four major multilayered archeological sites in the southern Levant (Hazor and Megiddo), northern Levant (Ebla), and western Upper Mesopotamia (Mari). We report new archeointensity data, obtained using the ThellierâIZZIâMagIC and the Triaxe methods, from six strata at Hazor and four radiocarbonâdated strata at Megiddo. From 39 pottery fragments, 199 specimens passed our selection criteria, from which we calculated the mean archeointensity for each stratum. To strengthen the comparison of these data with previously published data from Mari and Ebla, obtained using the Triaxe method, we conducted a blind test of the methods that resulted in indistinguishable results or a difference of less than 1Â ÎŒT. The synchronized compilation, constrained by radiocarbon data from Megiddo, displays a Vâshaped pattern with a prominent minimum of at least 200Â years centered around the 18th century BCE. The study highlights the importance of stacking archeomagnetic data obtained by different archeointensity methods only after crossâtesting the methods and ensuring that archeological samples were dated in a consistent manner
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