Automatic Discrimination of Color Retinal Images using the Bag of Words Approach

International audienceDiabetic retinopathy (DR) and age related macular degeneration (ARMD) are among the major causes of visual impairment all over the world. DR is mainly characterized by small red spots, namely microaneurysms and bright lesions, specifically exudates. However, ARMD is mainly identified by tiny yellow or white deposits called drusen. Since exudates might be the only visible signs of the early diabetic retinopathy, there is an increase demand for automatic diagnosis of retinopathy. Exudates and drusen may share similar appearances; as a result discriminating between them plays a key role in improving screening performance. In this research, we investigative the role of bag of words approach in the automatic diagnosis of retinopathy diabetes. Initially, the color retinal images are preprocessed in order to reduce the intra and inter patient variability. Subsequently, SURF (Speeded up Robust Features), HOG (Histogram of Oriented Gradients), and LBP (Local Binary Patterns) descriptors are extracted. We proposed to use single-based and multiple-based methods to construct the visual dictionary by combining the histogram of word occurrences from each dictionary and building a single histogram. Finally, this histogram representation is fed into a support vector machine with linear kernel for classification. The introduced approach is evaluated for automatic diagnosis of normal and abnormal color retinal images with bright lesions such as drusen and exudates. This approach has been implemented on 430 color retinal images, including six publicly available datasets, in addition to one local dataset. The mean accuracies achieved are 97.2% and 99.77% for single-based and multiple-based dictionaries respectively

Influence of cracks on the soil-atmosphere interaction: numerical coupled model of thermo- atmosphereporous media

Soil shrinks as it desiccates, and the magnitude of shrinkage can be large for clayey soils. The drying of soil leads to cracks formation, causing high suctions to develop within. Cracks expose the deep soil and more evaporation can be expected in dry periods. To illustrate the effect of cracking, a numerical model of soil-atmosphere interaction has been developed taking into account the thermo-fluid coupling of an unsaturated clay soil. The model is used to simulate the evolution of evaporation during the drying process. The main results show a significant influence of the presence of cracks on the evaporation. This study also offers a simple method for taking into account the presence of cracks in the soil-atmosphere exchange

Surface treatments for improving bond strength to prefabricated fiber posts: A literature review

This literature review summarizes the research on fiber post surface treatments and provides information related to their benefit in enhancing bond strength to composites, based on the results of original scientific full papers from peer-reviewed journals listed in Pub Med. The search was conducted using the terms "fiber post," "surface treatment" "surface conditioning," "etching" and "sandblasting." A consistent number of in vitro studies that investigated the surface treatment of fiber posts in an attempt to improve bond strength have been published to date. Their results have been summarized in the following categories: chemical treatments and micromechanical treatments of fiber post surfaces (or a combination of both principles). The majority of available literature data is based on studies that investigated different "chairside" post superficial treatments. According to the in vitro results, surface conditioning improves fiber post bonding properties, and the bond strength of pre-treated fiber posts to restorative materials is satisfactory. Long-term clinical studies are needed prior to making a general recommendation for their use

Meal-time Detection by Means of Long Periods Blood Glucose Level Monitoring via IoT Technology

Blood glucose level monitoring is of great importance, especially for subjects experiencing type 1 diabetes. Accurate monitoring of their blood glucose level prevents dangerous and life-threatening situations that might be experienced by those subjects. In addition, precise monitoring of blood glucose levels over long periods of time helps establishing knowledge about the daily mealtime routine which aids the medical staff to monitor subjects and properly intervene in hazardous cases such as hypo- or hyperglycemia. Establishing such knowledge will play a potential role when designing proper treatment intervention plan. In this research, we present a complete IoT framework, starting from hardware acquisition system to data analysis approaches that gives a hand for medical staff when long periods of blood glucose monitoring are essential for subjects. Also, this framework is validated with real-time data collection from 7 subjects over 10 successive days with temporal resolution of 5 minutes allowing for near real-time monitoring and analysis. Our results show the precisely estimated daily mealtime routines for 4 subjects out of the 7 with discard of 3 subjects due to huge data loss mainly. The daily mealtime routines for the 4 subjects are found to be matching to have a pattern of 4 periods of blood glucose level changes corresponding to the breakfast around 8 AM, the lunch around 5 PM, the dinner around 8 PM, and finally a within-day snack around 12 PM. The research shows the potential of IoT ecosystem in support for medically related studies

Thujone inhibits the function of α7-nicotinic acetylcholine receptors and impairs nicotine-induced memory enhancement in one-trial passive avoidance paradigm

Effects of thujone, a major ingredient of absinthe, wormwood oil and some herbal medicines, were tested on the function of α7 subunit of the human nicotinic acetylcholine (α7 nACh) receptor expressed in Xenopus oocytes using the two-electrode voltage-clamp technique. Thujone reversibly inhibited ACh (100 μM)-induced currents with an IC50 value of 24.7 μM. The effect of thujone was not dependent on the membrane potential and did not involve Ca2+-dependent Cl- channels expressed endogenously in oocytes. Inhibition by thujone was not reversed by increasing ACh concentrations. Moreover, specific binding of [125I] -bungarotoxin was not altered by thujone. Further experiments in SH-EP1 cells expressing human α7 nACh receptor indicated that thujone suppressed choline induced Ca2+ transients in a concentration-dependent manner. In rat hippocampal CA3-dentate gyrus synapses, nicotine-induced enhancement of long-term potentiation was also inhibited by thujone. Furthermore, the results observed in in-vivo one-trial passive avoidance paradigm show that thujone (1.25 mg/kg, i.p.) significantly impaired nicotine-induced enhancement of learning and memory in Wistar rats. Collectively, our results indicate that thujone inhibits the function of the α7-nACh receptor and impairs cellular and behavioral correlates of cholinergic modulation of learning and memory

Potentiometric Study of Acid-Base Interactions in Acetonitrile

The potentiometric titration curves of acids of different types were studied using piperidine and tetra-n-butylammonium hydroxide, (Bu4NOH), as titrants in acetonitrile (AN) as solvent. The effect of methanol addition on the shape of the potentiometric curves was discussed. The dissociation constants, KHA, and homoconjugation constants, KHA2- , of some acids were potentiometrically determined in AN. No exact correlation was found between KHA of the studied acids in AN and the corresponding values-in water. It was concluded that the acid characteristics, its anion properties, and the solvent . type are the most important factors determining KHA2-. The heteroconjugation constants, KAHA,- of some anions with different acids were also determined. K AHAc values for some substituted benzoic acids with reference to acetate ion were found to follow a linear free energy relationship with Hammett substituent constants