DNA amplified fingerprinting, a useful tool for determination of genetic origin and diversity analysis in Citrus

We used three short repetitive nucleotide sequences [(GTG)5, (TAC)5, and (GACA)4] either as radiolabeled probes for hybridization with restricted Citrus DNA or as single primers in polymerase chain reaction amplification experiments with total genomic DNA. We tested the ability of the sequences to discriminate between seedlings of zygotic or nuclear origin in the progeny of a Volkamer lemon #Citrus volkameriana# Ten. & Pasq.) tree. The genetic variability within two species [#Citrus sinensis# (L.) Osbeck (sweet oranges) and #Citrus reticulata# Blanco and relatives (mandarins)] was evaluated. DNA amplified figerprinting with single primers was the more successful technique for discriminating between nucellular and zygotic seedlings. Although we were not able to distinguish among 10 cultivars of #C. sinensis#, all 10 #C. reticulata# cultivars tested were distinguishable. However, it still is difficult to identify the putative parents of a hybrid plant when the two parental genomes are closely related. (Résumé d'auteur

The Extraction and Usage of Patterns from Video Data to Support Multi-Agent Based Simulation

The research work presented in this thesis is directed at addressing the knowledge acquisition bottleneck frequently encountered in computer simulation. The central idea is to extract the required knowledge from video data and use this to drive a computer simulation instead of the more conventional approach of interviewing domain experts and somehow encapsulating this knowledge in a manner whereby it can be used in the context of computer simulation. More specifically the idea presented in this thesis is to extract object location information from video data and then to mine this information to identify Movement Patterns (MPs) and then to utalise these MPs in the context of computer simulation. To act as a focus for the work rodent behaviour simulation was considered. Partly because video data concerning rodent behaviour was relatively easy to obtain and partly because there is a genuine need to achieve a better understanding of rodent behaviour. This is especially the case in the context of crop damage. There are a variety of computer simulation frameworks. One that naturally lends itself to rodent simulation is Multi Agent Based Simulation (MABS) whereby the objects to be simulated (rodents) are encapsulated in terms of software agents. In more detail the work presented is directed at a number of research issues in the context of the above: (i) mechanisms to identify a moving object in video data and extracting associated location information, (ii) the mining of MPs from the extracted location information, (iii) the representation of MPs in such a way that they are compatible with computer simulation frameworks especially MABS frameworks and (iv) mechanisms where by MPs can be utilized and interacted with so as to drive a MABS. Overall two types of mechanisms are considered, Absolute and Relative. The operation of rodent MABSs, driven using the proposed MP concept, is fully illustrated in the context of different categories of scenarios. The evaluation of the proposed MP driven MABSs was conducted by comparing real world scenarios to parallel simulated scenarios. The results presented in the thesis demonstrated that the proposed mechanisms for extracting locations, and consequently mining MPs, from video data to drive a MABS provides a useful approach to effective computer simulation that will have wide ranging benefits

COMPARATIVE EFFICACY OF SYNTHETIC AND BOTANICAL INSECTICIDES AGAINST SUCKING INSECT PEST AND THEIR NATURAL ENEMIES ON COTTON CROP

The Synthetic and botanical insecticides are relatively safer for environment and beneficial insects. The study was conducted in Rahim Yar Khan during the cotton cropping season 2014 to evaluate the comparative efficacy of two Synthetic insecticides i.e. Nitenpyram (Jasper 10% SL) and Pyriproxyfen (Bruce 10.8% EC) and two botanical extracts of Calotropic procera and Azadirachta indica, against sucking insect pest complex of cotton and their natural enemies. Upon reaching economic thresholds, the recommended field doses of all the insecticides were applied on cotton cultivar MNH-886. Data against sucking pests and their natural enemies was recorded 24 hours prior to insecticidal application and then 24, 48, 72 and 96 hours after insecticidal application. Results revealed that Nitenpyram was much toxic against sucking pests followed by Pyriproxyfen as compared to two botanical extracts. On the other hand, the synthetic insecticides did not prove safer for natural enemies as compared to botanical extracts. It was concluded that as an Integrated Pest Management (IPM) strategy, botanical extracts can be used at low infestation levels so that ecosystem service of biological control may be sustained

State of the art spatial visualization of the response of neovascularisation to anti-vascular endothelial growth factor therapy

PURPOSE: To visualize the mode of action of anti-vascular endothelial growth factor (anti-VEGFs) therapy on retinal neovascularization (RNV) in a patient with macular telangiectasia (MacTel) type 2 using a detailed three-dimensional data environment. OBSERVATION: A 60-year-old man presented with visual acuity loss and was diagnosed with MacTel type 2. Fluorescein angiography was not possible for safety reasons because of a history of severe reaction to fluorescein dye at his referring hospital. Optical coherence tomography angiography (OCTA) imaging revealed new retinal neovascular membranes (RNV) in the macula of both eyes. A marked reduction in the size of the RNV in both eyes was evident on volume-rendered three-dimensional OCTA retinal imaging after the first anti-VEGF injection. CONCLUSION AND IMPORTANCE: The ability to directly observe the effect of anti-VEGF injections on a RNV using three-dimensional OCTA was successfully demonstrated. This can be useful in patients with previous allergic and potentially lethal complications to fluorescein. In addition, enhanced three-dimensional spatial display of RNV leads to a greater understanding of the perfusion profile and the anatomical changes that occur in ocular neovascularization relative to surrounding tissue. This has the potential to provide insight into the pathobiology of angiogenesis

Repeatability of swept-source optical coherence tomography retinal and choroidal thickness measurements in neovascular age-related macular degeneration

BACKGROUND: The aim was to determine the intrasession repeatability of swept-source optical coherence tomography (SS-OCT)-derived retinal and choroidal thickness measurements in eyes with neovascular age-related macular degeneration (nAMD). METHODS: A prospective study consisting of patients with active nAMD enrolled in the Distance of Choroid Study at Moorfields Eye Hospital, London. Patients underwent three 12×9 mm macular raster scans using the deep range imaging (DRI) OCT-1 SS-OCT (Topcon) device in a single imaging session. Retinal and choroidal thicknesses were calculated for the ETDRS macular subfields. Repeatability was calculated according to methods described by Bland and Altman. RESULTS: 39 eyes of 39 patients with nAMD were included with a mean (±SD) age of 73.9 (±7.2) years. The mean (±SD) retinal thickness of the central macular subfield was 225.7 μm (±12.4 μm). The repeatability this subfield, expressed as a percentage of the mean central macular subfield thickness, was 23.2%. The percentage repeatability of the other macular subfields ranged from 13.2% to 28.7%. The intrasession coefficient of repeatability of choroidal thickness of the central macular subfield was 57.2 μm with a mean choroidal thickness (±SD) of 181 μm (±15.8 μm). CONCLUSIONS: This study suggests that a change >23.2% of retinal thickness and 57.2 μm choroidal thickness in the central macular subfield is required to distinguish true clinical change from measurement variability when using the DRI OCT-1 device to manage patients with nAMD

Progression of Retinopathy Secondary to Maternally Inherited Diabetes and Deafness – Evaluation of Predicting Parameters

PURPOSE: To investigate the prognostic value of demographic, functional, and imaging parameters on retinal pigment epithelium (RPE) atrophy progression secondary to Maternally Inherited Diabetes and Deafness (MIDD) and to evaluate the application of these factors in clinical trial design. DESIGN: Retrospective observational case series. METHODS: Thirty-five eyes of 20 patients (age range, 24.9-75.9 years) with genetically proven MIDD and demarcated RPE atrophy on serial fundus autofluorescence (AF) images were included. Lesion size and shape-descriptive parameters were longitudinally determined by two independent readers. A linear mixed effect model was used to predict the lesion enlargement rate based on baseline variables. Sample size calculations were performed to model the power in a simulated interventional study. RESULTS: The mean follow-up time was 4.27 years. The mean progression rate of RPE atrophy was 2.33 mm2/year revealing a dependence on baseline lesion size (+0.04 [0.02-0.07] mm2/year/mm2, p<0.001), which was absent after square root transformation. The fovea was preserved in the majority of patients during the observation time. In the case of foveal involvement, the loss of visual acuity lagged behind central RPE atrophy in AF images. Sex, age, and number of atrophic foci predicted future progression rates with a cross-validated mean absolute error of 0.13 mm/year and to reduce the required sample size for simulated interventional trials. CONCLUSIONS: Progressive RPE atrophy could be traced in all eyes using AF imaging. Shape-descriptive factors and patients' baseline characteristics had significant prognostic value, guiding appropriate subject selection and sample size in future interventional trial design

Evaluation of Nonperfused Retinal Vessels in Ischemic Retinopathy

Purpose: Retinal ischemia has been traditionally assessed by fluorescein angiography, visualizing perfused vessels. However, this method does not provide any information about nonperfused vessels, and although it is often assumed that vessels in ischemic areas regress, we know little about how nonperfused retinal vessels change over time. Here, we aim to learn more about the long-term fate of nonperfused vessels in the retinal vasculature. Methods: Optical coherence tomography (OCT) was used to visualize perfusion as well as structural properties of the retinal vasculature in patients suffering from retinal vascular occlusions. In addition, postmortem tissue from a patient with long standing (6 years) central retinal vein occlusion (CRVO) was investigated, using immunohistochemistry on whole-mount retina and paraffin sections to visualize blood vessel components. Results: Comparing OCT angiography with enface OCT images revealed that in ischemic areas of the retina, nonperfused, larger vessels could be detected as hyperreflective structures in enface OCT images. Furthermore, analysis of a postmortem tissue sample from a CRVO patient with a large nonperfused region in the macula, revealed preservation of the basement membrane from all retinal vessels, including nonperfused, acellular vessels of all calibers. Conclusions: Our data suggests long-term preservation of vascular basement membrane in ischemic retina. This has implications for therapeutic approaches aiming to alleviate retinal ischemia via the regeneration of damaged vessels

Quantification and Predictors of OCT-Based Macular Curvature and Dome-Shaped Configuration: Results From the UK Biobank

PURPOSE. To investigate macular curvature, including the evaluation of potential associations and the dome-shaped macular configuration, given the increasing myopia prevalence and expected associated macular malformations. METHODS. The study included a total of 65, 440 subjects with a mean age (± SD) of 57.3 ± 8.11 years with spectral-domain optical coherence tomography (OCT) data from a unique contemporary resource for the study of health and disease that recruited more than half a million people in the United Kingdom (UK Biobank). A deep learning model was used to segment the retinal pigment epithelium. The macular curvature of the OCT scans was calculated by polynomial fit and evaluated. Further, associations with demographic, functional, ocular, and infancy factors were examined. RESULTS. The overall macular curvature values followed a Gaussian distribution with high inter-eye agreement. Although all of the investigated parameters, except maternal smoking, were associated with the curvature in a multilinear analysis, ethnicity and refractive error consistently revealed the most significant effect. The prevalence of a macular dome-shaped configuration was 4.8% overall, most commonly in Chinese subjects as well as hypermetropic eyes. An increasing frequency up to 22.0% was found toward high refractive error. Subretinal fluid was rarely found in these eyes. CONCLUSIONS. Macular curvature revealed associations with demographic, functional, ocular, and infancy factors, as well as increasing prevalence of a dome-shaped macular configuration in high refractive error including high myopia and hypermetropia. These findings imply different pathophysiologic processes that lead to macular development and might open new fields to future myopia and macula research