An image processing decisional system for the Achilles tendon using ultrasound images

The Achilles Tendon (AT) is described as the largest and strongest tendon in the human body. As for any other organs in the human body, the AT is associated with some medical problems that include Achilles rupture and Achilles tendonitis. AT rupture affects about 1 in 5,000 people worldwide. Additionally, AT is seen in about 10 percent of the patients involved in sports activities. Today, ultrasound imaging plays a crucial role in medical imaging technologies. It is portable, non-invasive, free of radiation risks, relatively inexpensive and capable of taking real-time images. There is a lack of research that looks into the early detection and diagnosis of AT abnormalities from ultrasound images. This motivated the researcher to build a complete system which enables one to crop, denoise, enhance, extract the important features and classify AT ultrasound images. The proposed application focuses on developing an automated system platform. Generally, systems for analysing ultrasound images involve four stages, pre-processing, segmentation, feature extraction and classification. To produce the best results for classifying the AT, SRAD, CLAHE, GLCM, GLRLM, KPCA algorithms have been used. This was followed by the use of different standard and ensemble classifiers trained and tested using the dataset samples and reduced features to categorize the AT images into normal or abnormal. Various classifiers have been adopted in this research to improve the classification accuracy. To build an image decisional system, a 57 AT ultrasound images has been collected. These images were used in three different approaches where the Region of Interest (ROI) position and size are located differently. To avoid the imbalanced misleading metrics, different evaluation metrics have been adapted to compare different classifiers and evaluate the whole classification accuracy. The classification outcomes are evaluated using different metrics in order to estimate the decisional system performance. A high accuracy of 83% was achieved during the classification process. Most of the ensemble classifies worked better than the standard classifiers in all the three ROI approaches. The research aim was achieved and accomplished by building an image processing decisional system for the AT ultrasound images. This system can distinguish between normal and abnormal AT ultrasound images. In this decisional system, AT images were improved and enhanced to achieve a high accuracy of classification without any user intervention

Effect of the experimental parameters on the shape and formation kinetics of SiNWs formed by electroless chemical etching in aqueous AgNO3/HF/H2O2 solution

The discovery at the beginning of 1990 of carbon nanotubes awaked the interest for one-dimensional (1D) nanostructures. Currently, silicon nanowires (SiNWs) formed by electroless chemical etching in aqueous Ag- NO3/HF/H2O2 solution, arouse great interest due to their physical properties and potential applications. The understanding of physical-chemical phenomena that occur during the formation of SiNWs, the effect of etching parameters on their morphology, the formation mechanism and formation kinetic raise many questions. In this paper, we investigate the effect of etching parameters; namely AgNO3 concentration, HF concentration, etching time and the volume of H2O2 on the shape of obtained nanostructures. The formation kinetic was investigated by studying the effect of the etching time on the morphology of obtained nanostructures. SiNWs studied in this work were formed on a P type and (100) oriented monocrystalline silicon substrate. Characterization of formed SiNWs was performed using a scanning electron microscope (SEM)

Increased 30-Day Mortality in Very Old ICU Patients with COVID-19 Compared to Patients with Respiratory Failure without COVID-19

Purpose: The number of patients ≥ 80 years admitted into critical care is increasing. Coronavirus disease 2019 (COVID-19) added another challenge for clinical decisions for both admission and limitation of life-sustaining treatments (LLST). We aimed to compare the characteristics and mortality of very old critically ill patients with or without COVID-19 with a focus on LLST. Methods: Patients 80 years or older with acute respiratory failure were recruited from the VIP2 and COVIP studies. Baseline patient characteristics, interventions in intensive care unit (ICU) and outcomes (30-day survival) were recorded. COVID patients were matched to non-COVID patients based on the following factors: age (± 2 years), Sequential Organ Failure Assessment (SOFA) score (± 2 points), clinical frailty scale (± 1 point), gender and region on a 1:2 ratio. Specific ICU procedures and LLST were compared between the cohorts by means of cumulative incidence curves taking into account the competing risk of discharge and death. Results: 693 COVID patients were compared to 1393 non-COVID patients. COVID patients were younger, less frail, less severely ill with lower SOFA score, but were treated more often with invasive mechanical ventilation (MV) and had a lower 30-day survival. 404 COVID patients could be matched to 666 non-COVID patients. For COVID patients, withholding and withdrawing of LST were more frequent than for non-COVID and the 30-day survival was almost half compared to non-COVID patients. Conclusion: Very old COVID patients have a different trajectory than non-COVID patients. Whether this finding is due to a decision policy with more active treatment limitation or to an inherent higher risk of death due to COVID-19 is unclear.info:eu-repo/semantics/publishedVersio

Mechanistic studies on aziridinyl-benzoquinones and CCNU [1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea] in cultured tumour cells

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The use of chemical vapor etching in multicrystalline silicon solar cells

With the purpose to increase the light confinement and the efficiency of silicon solar cells, the reflection of the surface emitter needs to be minimized and the minority carrier collection improved. This improvement is currently achieved by the application of the chemical vapor etching (CVE) technique. In this paper, we investigate the effects of CVE on surface texturing and silicon grooving. CVE-based porous silicon (PS) was found to be a good antireflection and passivation layer for multicrystalline Si (mc-Si) solar cells. As a result, the reflectivity of the mc-Si solar cell decreases by about 60% of its initial value in the 650–950 nm spectral range and the internal quantum efficiency improves by 30% after PS application in the 400–700 nm spectral range. CVE can be used for surface texturing of single or mc-Si Si wafer leading to lower surface reflectivity and reduction of the dead layer. The chemical vapor etching techniques enabled realize buried metallic contacts by grooving mc-Si silicon wafers. The spectral response of mc-Si solar cells was found to enhance of about 12% in the long wavelength range when a rear buried metallic contacts is achieved, while a significant increase of about 35% was observed at short wavelengths (400–650 nm spectral range) subsequent front grid buried metallic contacts realization

Effect of rapid oxidation on optical and electrical properties of silicon nanowires obtained by chemical etching

In the present work, we report the investigation of passivated silicon nanowires (SiNWs) having an average radius of 3.7 μm, obtained by chemical etching of p-type silicon (p-Si). The surface passivation of the SiNWs was performed through a rapid oxidation conducted under a controlled atmosphere at different temperatures and durations. The morphology of the SiNWs was examined using a scanning electron microscope (SEM) that revealed a wave-like structure of dense and vertically aligned one-dimensional silicon nanostructures. On the other hand, optical and electrical characterizations of the SiNWs were studied using a UV-Vis-NIR spectrometer, the Fourier transform infrared spectroscopy (FTIR) and I-V measurements. The reflectance of SiNWs has been dropped to approximately 2% in comparison to that of bare p-Si. This low reflectance slightly increased after carrying out the rapid thermal annealing. The observed behavior was attributed to the formation of a SiO2 layer, as confirmed by FTIR measurements. Finally, the electrical measurements have shown that the rapid oxidation, at certain conditions, contributes to the improvement of the electrical responses of the SiNWs, which can be of great interest for photovoltaic applications

Numerical and Experimental Study of the Front Surface Recombination Velocities and Base Widths Effect in Multi-Crystalline Silicon Solar Cell Quantum Efficiency

International audiencePhotovoltaic research activities are related to material innovation that can be obtained at a comparatively low cost. Semiconductor p-type multi-crystalline Czochralskyc (CZ)-grown silicon wafers were used in this study. The effects of front surface recombination velocities and base thickness in solar cells' quantum efficiency are theoretically calculated. The results denote that both the surface recombination velocities and the base widths significantly impact the quantum efficiency. The results are of universal technical importance in designing solar cells and their surface structures. The main goal of this paper was to confirm the validity of the above theoretical calculations; for this purpose, silicon solar cells with front-thin porous silicon and rear interdigitated contact have been produced. A good agreement was obtained between experimentally obtained solar cells' quantum efficiency data and the theoretical results. Therefore, the quantum efficiency of the mc-Si solar cells with porous silicon and rear interdigitated contact was enhanced up to 25% at 580-1100 nm wavelength range and up to 50% at short wavelength (400-570 nm), compared to reference mc-Si solar cells. The obtained results indicate that the rear interdigitated contact maximizes the surface area of the metal contact and improves the current collection. At the same time, the porous silicon layer passivates the front surface and reduces recombination losses

Aphid (Hemiptera : Aphidoidea) diversity in Tunisia in relation to seed potato production

International audienceWinged morphs of aphids were investigated from 2002 to 2004 in 4 Tunisian regions of potato seeds production in order to know the aphid diversity and the potential vectors of Potato Virus Y. This is a very important contribution to the knowledge of aphid fauna in Maghreb. A total of 50,030 aphids were caught using yellow water traps and one suction trap. 130 taxa were identified including 103 species. Ten species are well represented in all regions prospected and typical species were also observed in every region. Some differences in species diversity appeared between regions which are discussed considering weather condition and vegetation