Ecotoxicity effects of oil Water Accommodated Fractions and oil Water Accommodated Fractions + Dispersant on cold environments: Acarita tonsa based bioassays and microbial community dynamics as monitoring tools

224 p.La contaminación por petróleo es un problema importante en los océanos y mares, especialmente en ambientes fríos y regiones polares, donde los procesos de remediación son más complejos y los ecosistemas son muy vulnerables. Durante un vertido de petróleo diversos factores meteorológicos y el movimiento de las olas favorecen la integración de los hidrocarburos hidrofílicos en la columna de agua, siendo el producto resultante la conocida como fracción acomodada del petróleo en el agua (WAF), que suele estar compuesta principalmente, aunque no solo, por hidrocarburos aromáticos policíclicos (HAPs). Históricamente como forma de remediación ante los vertidos de petróleo se ha utilizado la incorporación de dispersantes químicos que favorecen la degradación del petróleo. Sin embargo, diversos estudios han demostrado que los dispersantes químicos pueden tener efectos adversos sobre los organismos marinos. El objetivo de este proyecto de Tesis doctoral ha sido estimar el posible impacto del WAF de un petróleo nafténico del Atlántico Norte (NNA), con o sin la adición del dispersante químico Finasol OSR52, mediante bioensayos in vivo con copépodos y el estudio de alteraciones en comunidades microbianas. Los bioensayos con el organismo modelo Acartia tonsa demostraron que el NNA WAF fue menos tóxico que los WAFs obtenidos a partir de destilados de fuel oil (IFO 180 y Gasóleo de uso marítimo), que mostraron una alta toxicidad a distintos niveles de organización biológica (transcripción génica, reproducción y supervivencia) en los copépodos. Al añadir el dispersante químico el NNA WAF fue más tóxico para los copépodos en términos de alteración de la transcripción génica, la reproducción y la mortalidad. En el caso de las comunidades microbianas, al examinar en condiciones de microcosmos los efectos del NNA WAF en solitario y NNA WAF con dispersante, se pudo observar que el dispersante no favoreció la biodegradación bacteriana de los compuestos procedentes del NNA WAF. Sin embargo, sí alteró las dinámicas de las comunidades microbianas, tanto en la columna de agua como en el sedimento, favoreciendo ciertos taxones. Se observó que las comunidades microbianas que poseían desde el inicio bacterias degradadoras de hidrocarburos, debido a un historial de exposición crónico a estos compuestos (legacy effects), fueron el principal impulsor de la degradación de los HAPs en la columna de agua y en los sedimentos. En conclusión, la integración de bioensayos de toxicidad in vivo con copépodos y el estudio de la dinámica de las comunidades microbianas ofrecen una visión amplia de los efectos y respuestas en ecosistemas sensibles que puede causar un escenario de vertido de petróleo y la adición de dispersantes químicos

Low Power Circuit Design in Sustainable Self Powered Systems for IoT Applications

The Internet-of-Things (IoT) network is being vigorously pushed forward from many fronts in diverse research communities. Many problems are still there to be solved, and challenges are found among its many levels of abstraction. In this thesis we give an overview of recent developments in circuit design for ultra-low power transceivers and energy harvesting management units for the IoT. The first part of the dissertation conducts a study of energy harvesting interfaces and optimizing power extraction, followed by power management for energy storage and supply regulation. we give an overview of the recent developments in circuit design for ultra-low power management units, focusing mainly in the architectures and techniques required for energy harvesting from multiple heterogeneous sources. Three projects are presented in this area to reach a solution that provides reliable continuous operation for IoT sensor nodes in the presence of one or more natural energy sources to harvest from. The second part focuses on wireless transmission, To reduce the power consumption and boost the Tx energy efficiency, a novel delay cell exploiting current reuse is used in a ring-oscillator employed as the local oscillator generator scheme. In combination with an edge-combiner power amplifier, the Tx showed a measured energy efficiency of 0.2 nJ=bit and a normalized energy efficiency of 3.1 nJ=bit:mW when operating at output power levels up to -10 dBm and data rates of 3 Mbps

Effervescent Atomization of Suspensions in a Gaseous Cross Flow

Atomization of liquids (pure liquids and suspensions) plays an important role in numerous industrial fields and applications. One of the main important applications is in thermal spraying processes which is the primary motivation for this study. The main trend in thermal spray processes is to coat with sub-micron and nano sized particles due to the superior performance of fine microstructured coatings. Recently, thermal spraying processes are using the suspension spraying technique. The breakup of a suspension in the atomization process differs from that of a pure liquid by the influence of the suspended particles on the fragmentation kinetics. In suspension spraying process, different types of atomizers are used but clogging problems can occur due to the suspension properties. Effervescent atomizers have shown to be a good alternative to the conventional atomizers to solve clogging issue when liquids with large variety of viscosity and density such as suspensions are atomized. In this study, effervescent atomization of suspensions in a crossflow of air is investigated experimentally. The tests have been performed at different liquid-to-gas momentum flux ratios (q) and different gas to liquid ratios (GLR). Hydrophilic and hydrophobic particles are used in the experiments. Shadowgraphy and image processing have been used in order to capture the penetration height of the spray. New correlations have been developed to predict the spray penetration height of suspensions in case the non-aerated liquid jet (GLR= 0) and for the aerated liquid jet (GLR ≠ 0). Moreover, suspensions properties such as viscosity and surface tension have a crucial effect on the atomization process. Because the atomization process and droplet formation occur in a very short timescale of the order of milliseconds, it is necessary to analyze the rapid change of the affecting suspension properties related to this timescale especially surface tension. Therefore, the time changing (dynamic) surface tension is more appropriate to be analyzed than static surface tension. In this work, the dynamic surface tension of suspensions is investigated using a combined analytical and experimental approach based on the physics governing the oscillation of elliptical jets. The dynamic surface tension of suspensions liquids in the timescale of milliseconds is calculated. The effect of the dynamic surface tension of suspension on its atomization process has been analyzed

Cranioplasty: A New Perspective

AIM: This work aims to present the different indication, benefits, possible complications and methods used for fixation of methyl methacrylate in cranioplasty. Also, 50 cases will be presented demonstrating the different aetiologies of the defects, and the different techniques used for fixation of methyl methacrylate in cranioplasty. METHODS: This investigation included a prospective study to be carried out on 50 patients with cranial defects of different aetiologies, sites and sizes to be operated upon in Cairo University Hospitals starting from August 2016 to April 2017.RESULTS: The principal aims of cranioplasty in this study are to restore aesthetic contour and to provide cerebral protection. However, it has been noted that a great improvement occurs in cerebral blood flow and cerebral perfusion after cranioplasty. CONCLUSION: Ball and socket technique appear to be a simple, safe economic and efficient method for fixation of cranioplasty flap. The high incidence of development of postoperative seroma suggests the necessity of-of a subgaleal drain placement for 48 hours. &nbsp

Traumatic Dural Venous Sinuses Injury

The traumatic dural venous sinus injury is one of the most dangerous complications of TBI, either due to fatal intracranial compressing venous bleeding, or disturbing the intracranial pressure which could be caused by injury to the SSS On the other hand, post traumatic dural sinus thrombosis is considered a rare complication which may lead to hemorrhagic infarction with its serious consequences including epilepsy, neurological deficits, or death. Therefore, knowledge of the appropriate treatment of this kind of head injury is essential

Comparison between Results of Microdiscectomy and Open Discectomy in Management of High-Level Lumbar Disc Prolapse

AIM: This work aims to compare between results of microdiscectomy and open discectomy in management of high-level lumbar disc prolapse. METHODS: This is a controlled randomised study, where patients having upper lumbar disc herniations were evaluated preoperatively both clinically and radiologically, randomisation was planned to perform open discectomy in odd number patients and to perform microdiscectomy in even number patients, patients were evaluated and followed up for deficits and outcomes. RESULTS: We operated ten patients in this study, five cases were operated upon with microdiscectomy, and five cases were operated upon with open discectomy, the median age of presentation in this study was 44 years, there were five males and five females, postoperative pain improvement was better in microdiscectomy. Hospital stay, blood loss, bone loss and postoperative complications were less in microdiscectomy. CONCLUSION: Microdiscectomy allows good surgical visualisation and is less traumatic to the involved tissues. The results of this study indicated that microsurgery reduces hospitalisation time, improves the overall surgery-related outcome. The main differences between the two procedures were the length of the incision and blood loss. We found that lumbar microdiscectomy allows patients earlier return to work and normal life with less reliance on postoperative narcotic analgesic agents