161 research outputs found

    Anti-schistosoma single-domain antibody-nanoparticles conjugate: a novel tool for diagnostic and therapeutic applications

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    Nanotechnology has enthused excessive expectations in recent years, particularly in the biology and biomedical fields. Carbon-coated metallic nanomagnets reveal significant physicochemical properties, which are referred to as superparamagnetism, that when designed appropriately can be utilized to generate novel diagnostic and therapeutic applications for a wide range of biologically hazardous species. Schistosomiasis is a chronic parasitic disease that can infect both humans and animals, particularly cattle. It is caused by a trematode blood fluke of the genus Schistosoma which belong to the schistosomatidae family. At least 200 million individuals are infected in 75 countries while 600 million people are exposed to infection and are potentially victim of this parasite. Schistosomiasis is still recognized as one of the most neglected disease, the current available diagnostic techniques are deficient in accuracy and are incapable of identifying the disease in its early stages. Moreover, they suffer from prolonged examination time. Besides, the poorly available therapeutic drugs started to lose their efficacy and the parasite started to develop resistance against most of them, which create an imperative need for developing novel diagnostic and therapeutic tools. The humoral immune response of the Camelidae is unique since these animals possess functional heavy-chain only antibodies in addition to the classical antibodies. Thanks to recombinant DNA technology, a series of single domain antigen binding entities can be produced against specific schistosomeâ s parasite antigens. These binders possess a number of distinctive biophysical properties that offer particular advantages in various theranostic applications. Finally, nanomagnetism was selected to represent a certain phenomena through which we demonstrated, to our knowledge for the first time, the successful construction of effective and functional bioconjugate system which is appropriate for a plethora of diagnostic and therapeutic applications. The main thrust of this research work was towards the developing of single domain antibodies against Schistosoma mansoni gut specific antigen and execratory secretory antigen. In parallel, state-of-the-art methodologies were implemented for constructing a bioconjugate system composed of sdAb and graphene-coated metallic nanomagnet tagged with a carboxyl terminal. Finally, the well-established metastable technetium-99 (99mTc) is used for labeling the conjugate for studying the possibility of active and magnetic targeting of the nano-structured system i.e. 99mTc-sdAb-Fe@C-MNP conjugates

    Mechanical Erosion Investigation Through the Solid Rocket Motor’s Nozzle

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    The solid rocket motor (SRM) is considered one of the essential engines that facilitatesaerospace research; thus, investigating the propellant burning process is vital. One of the challenges facing its growth is the oxidization of the aluminum into aluminum oxide at the exhaust’s high pressures and temperatures. The oxidized aluminum forms agglomerates, impinge on the exit nozzle walls, causing severe damage (erosion) to the nozzle material. Thus, the present work attempts to investigate and reduce this erosion. Two different approaches are followed in the current work, the first one aims to better understand the aluminum oxide agglomerates break-up mechanism and the factors affecting it experimentally (subsonic condition due to the safety purposes limitations), while the other establishes a numerical model to predict the nozzle mechanical erosion within the rocket’s combustion chamber severe conditions. The breakup process and some factors affecting it are investigated in three sections. Twophaseair-water flow experimental set-up is used, as a substitute for liquid aluminum agglomerates and exhaust combustion gases, in the three sections. The first section’s experimental results show that increasing the exhaust air velocity enhances the droplet\u27s break-up tendency to reduce the average diameter and increase droplet numbers per the testing channel volume. Numerical models were constructed and validated using the experimental results. The percentage error in the droplets’ average diameter and the number is between 6–15% and 8-18%. Furthermore, the effect of reducing the liquid surface tension was studied. The results showed that it facilitates water bodies’ separation from the interface surface, because of the reduced bounding forces between surface’s molecules, which enhances the break-up process (0.5-17% increase in the droplets’ average diameter and 4-100% increase in its number) and reduce the droplets impact on the nozzle walls, hence reduce the SRM nozzle erosion problem. While the second section investigated the breakup process at different water flow rates andconstant air velocity, where the results were used to validate a numerical model. The results revealed an excellent acceptance between the numerical, the experimental data (6-19%), and the effect of increasing the water flow rate on the break-up mechanism. The validated numerical model was further used to study the airflow acceleration impact on the break-up process. It was found that applying acceleration to the airflow subjects the water surface to rapid and sudden changes in the relative velocity between the gas and liquid, thus separating more water fragments from the primary liquid. In other words, it enhances the break-up process by reducing the average diameter with a range from 6.5% to 9% compared to the no-acceleration case and increasing the average droplets’ number [8.5-17%]. Finally, the third section investigated the submerged nozzle configuration on the breakupprocess under different air and water flow rates, in addition compared between the submerged nozzle and the external one. It was found that having a submerged nozzle enhances the droplets breakup in the nozzle convergent section due to the existence of the recirculation zones. However, the separated droplets will have higher velocity to hit the walls with, hence a supersonic model simulates the actual conditions within the rocket is essential to decisively conclude the submerged nozzle effect on the nozzle mechanical erosion. Erosion prediction of the solid propellent nozzle is vital for its design process. Thus, thesecond approach employing a multi-phase numerical model is established based on the Eulerian- Lagrangian approach to model the aluminum particles burning inside the combustion chamber, in addition to simulating the mechanical erosion of the nozzle. The numerical model is validated against numerical and experimental results from the literature. Then the validated model will be further used to investigate the SRM nozzle erosion at different boundary conditions, nozzle configurations, particles, and propellant properties. First the model was used to simulate the agglomerates\u27 break-up, in addition to predicting the mechanical erosion for aluminum particles with lower surface tension. The results showed that applying the Reitz-Diwakar breakup model reduces the erosion rate by 6.2% - 24% depending on the injected droplets. In addition, it was found that a decrease in the erosion rate by 1% to 4.5% can be achieved by reducing the aluminum additive\u27s surface tension by 15%. Then, an investigation of the effect of increasing the propellant aluminum content anddifferent particles’ injection velocity on the nozzle mechanical erosion was conducted and the results showed that having higher aluminum content increases the nozzle erosion by 4-10% compared to the 15% case. Furthermore, the aluminum particles will not fully burn within the combustion chamber and will participate in the nozzle erosion. In the end, having particles with higher initial velocity at the burning surface increases the nozzle mechanical erosion, despite of the incident mass flux decline. Finally, the submerged nozzle configuration effect on the mechanical erosion was studiedat seven particle diameters and was compared against the external nozzle results. And it was concluded that comparing the external nozzle and submerged nozzle configurations in terms of the predicted mechanical erosion, the external nozzle will perform better than the submerged one as lower mechanical erosion exists in its different sections

    Intravitreal injection with anti-vascular endothelial growth factor (anti-VEGF) in diabetic macular edema (DME) versus vitrectomy with internal limiting membrane (ILM) peeling with anti-VEGF as an adjuvant

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    Summary Background: Diabetic macular edema (DME) is a globally growing health problem and considered the most common form of sight-threatening retinopathy in diabetic patients. Although focal or grid laser photocoagulation was the mainstay of treatment, anti-vascular endothelial growth factor (VEGF) agents are now the standard of care. However, these therapies are expensive and some patients show inadequate response. Purpose: To determine the effect of pars plana vitrectomy (PPV) for DME with preoperative intravitreal bevacizumab (IVB) compared to anti-VEGF only. Methods: This was a retrospective study between 2011 and 2016 of 260 eyes of 130 patients who had vitrectomy for DME (n=130, PPV group, single surgeon AV) and patients who had IVI of anti-VEGF only (n=130, IVI group) were followed for at least 12 month. Charts were reviewed for best corrected visual acuity (BCVA), central macular thickness (CMT) measured by optical coherence tomography (OCT). Results: The mean BCVA in LogMAR improved from 1.08 ± 0.64 at baseline to 0.71 ± 0.55 at 12-month in the PPV group (P < 0.0001) and in the IVI group, from baseline 0.49 ± 0.39 to 0.42 ± 0.36 at 12-month (P < 0.029). The mean CMT improved from 442 ± 200 μm at baseline to 348 ±149 μm at 12-month in the PPV group (P < 0.001). The mean CMT improved from 439 ± 166 μm at baseline to 368 ± 144 μm μm at 12-month in the IVI group (P < 0.001). Preoperative IVB, compared to without IVB, leads to reduction in intraoperative (6 cases vs. 10 cases) and postoperative bleeding (3 cases vs. 13 cases). Conclusion: Vitrectomy with internal limiting membrane peeling is a cost-effective procedure which consistently results in central macular thickness reduction and leads to clinically significant improvement in BCVA comparable to serial intravitreal injection of anti-VEGF. Careful patient selection and meticulous preoperative OCT assessment are critical steps in the decision-making process. Preoperative intravitreal bevacizumab was associated with reduced intraocular bleeding intra- and postoperatively. The complication rate of vitrectomy is low and similar to what has been reported for this procedure. A large, comparative, prospective, randomized clinical trial of these two treatments is needed to determine which therapy is more effective

    A taxonomy of testimonial smothering

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    Kristie Dotson formulates testimonial smothering as a form of testimonial oppression where a speaker truncates or removes the content of her testimony leaving the testimony empty from any content for which the hearers demonstrated testimonial incompetence. On Dotson’s account of smothering, the speaker empties her testimony from all content relevant to the domain of exchange. However, Dotson’s account does not include or cover instances where a speaker smothers her testimony, yet her smothered testimony contains some content relevant to the domain of exchange. In this thesis, I present a more detailed analysis of testimonial smothering to showcase different ways in which oppressed speakers interact in exchanges in which they are oppressed. I take Dotson’s notion of smothering to be one form of testimonial smothering, which I call smothering via emptying. I introduce two other types of smothering, smothering via altering and smothering via echoing, to encompass cases where a speaker’s smothered testimony is not empty from content relevant to the domain of exchange. Then I use the taxonomy of testimonial smothering to showcase ways in which oppressed speakers can contribute to conversations in which they are oppressed.https://www.ester.ee/record=b550775

    Program of Educational Cells for Education of Syrian Refuges

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    &nbsp; الملخص:&nbsp;هدفت الورقة الحالية لعرض ملامح برنامج لتعليم النازحين السوريين بمسمى (برنامج الخلايا التعليمية)، واستعرضت رؤية البرنامج وفلسفته، ومكوناته، وتشكيل اللجان المقترحة لإدارته ومهامها، وأهدافها، ومرتكزات التعليم ومميزاتها، وأسس التعليم في ضوئها، ونواتج التعلم المستهدفة، وأنماط التعليم والتعلم الملائمة لها، ودور المجتمع المحلي في دعم البرنامج، وكيفية تحفيز النازحين للمشاركة، وبعض المعوقات المحتملة.&nbsp;The paper aims to present the features of an Educational program for the Syrian Refuges, which named "the educational cell program". The paper reviewed vision, philosophy and components of the program, the formation of the proposed committees for its administration and functions, its objectives, the foundations and characteristics of education, the educational outcomes, and the role of the community in supporting the program, how to motivate IDPs to participate, and some potential constraints

    Cloud Computing Security, An Intrusion Detection System for Cloud Computing Systems

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    Cloud computing is widely considered as an attractive service model because it minimizes investment since its costs are in direct relation to usage and demand. However, the distributed nature of cloud computing environments, their massive resource aggregation, wide user access and efficient and automated sharing of resources enable intruders to exploit clouds for their advantage. To combat intruders, several security solutions for cloud environments adopt Intrusion Detection Systems. However, most IDS solutions are not suitable for cloud environments, because of problems such as single point of failure, centralized load, high false positive alarms, insufficient coverage for attacks, and inflexible design. The thesis defines a framework for a cloud based IDS to face the deficiencies of current IDS technology. This framework deals with threats that exploit vulnerabilities to attack the various service models of a cloud system. The framework integrates behaviour based and knowledge based techniques to detect masquerade, host, and network attacks and provides efficient deployments to detect DDoS attacks. This thesis has three main contributions. The first is a Cloud Intrusion Detection Dataset (CIDD) to train and test an IDS. The second is the Data-Driven Semi-Global Alignment, DDSGA, approach and three behavior based strategies to detect masquerades in cloud systems. The third and final contribution is signature based detection. We introduce two deployments, a distributed and a centralized one to detect host, network, and DDoS attacks. Furthermore, we discuss the integration and correlation of alerts from any component to build a summarized attack report. The thesis describes in details and experimentally evaluates the proposed IDS and alternative deployments. Acknowledgment: =============== • This PH.D. is achieved through an international joint program with a collaboration between University of Pisa in Italy (Department of Computer Science, Galileo Galilei PH.D. School) and University of Arizona in USA (College of Electrical and Computer Engineering). • The PHD topic is categorized in both Computer Engineering and Information Engineering topics. • The thesis author is also known as "Hisham A. Kholidy"

    Effect of Operational and Design Parameters on Desiccant-Assisted Hybrid Air-conditioning Systems Performance

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    Energy savings are a major goal in our lives because energy consumption is continuously increasing. We have studied in this paper four air conditioning systems, so that each system mainly consists of a vapor compression cycle and a rotating desiccant wheel. The thermodynamic analysis for air conditioning system, the heat exchanger, the ground heat exchanger and the evaporative water spray cooler were presented. Design and operating parameters including outlet air temperature, outlet air humidity, regeneration air temperature, and desiccant wheel speed are studied to assess its effect on the performance of the systems considered. This hybrid system significantly decreases the supplied air temperature at different four Systems. When the inlet air humidity ratio and the regeneration air temperature increase, the COPth of the air conditioning system decreases. When the desiccant wheel speed increased, the COPth of the air conditioning system decreases. COPth decreases with the increasing of the cooling load for the space and also decreases with the decreasing of the inlet air humidity ratio at process air. The results show that in these four systems, COPth is the highest at system 4 which contains desiccant wheel, heat exchanger and ground source circulation achieving an improvement of about 48 % and a consequent power consumption reduction of 20 %

    Finger-joint optimization of spruce lumber using finite element and statistical modelling

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    The primary objective of this thesis was to investigate and explore the feasibility of using a numerical 3-D finite element analysis (FEA) and statistical design of experiment methodology (DOE) to optimize finger-joint (FJ) configuration. This thesis provides guidelines to achieve structural behaviour of finger-joined elements that approaches non-finger-joined (NFJ) lumber. The optimum configurations will improve strength, save time, and money. A numerical 3-D finite element model was established using Abaqus FEA to simulate the interface between the two FJ adherent parts. The model was verified with experimental tests of actual FJ samples which showed a close agreement with the corresponding numerical model. An optimization of FJ lumber in horizontal, vertical and slope orientations were carried out to obtain the FJ geometry that achieves maximum structural performance of such lumber. A Reduced Quadratic Response Surface Model (RSM) and a Modified Two-Factor Interaction (2FI) experimental design were then used for both Normal and Inclined FJ categories, respectively. The statistical model were set up to assess the effect of the main factors: FJ-length, FJ-pitch, and FJ-tip width (tip thickness) and their interactions values on the stiffnesses. One additional parameter, FJ-Slope of three-levels was added with the Inclined FJ category. The obtained results showed clearly the potential of increasing FJ resistance by optimizing its geometry. In addition, it was observed that FJ in vertical orientation achieved higher structural performance close to the NFJ lumber comparing to the FJ in the horizontal orientation. Regression analysis was used to develop a design equations per each joint orientation (horizontal and vertical). The predicted equations will be useful to determine the optimum FJ geometry directly without the need to use a trial and error approach to achieve structural behaviours close to the NFJ lumber. Finally, enhancing these properties impact the behaviour and capacity of finger-joined elements at the serviceability and ultimate limit states
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