A study of the ionic diffusion under the effect of electric field (computer simulation with reference to biological membrane)

The biophysical studies of the biological system are far from being conclusive. Not only because this science is relatively recent, but also because of the lack of physical data. Also there are a lot of contradicting views among researchers as well as the poor theoretical interpretation of the reported experimental data. However, the advent of computer science with the considerable storage capability and highly vast calculations gives modeling techniques a great advantage and opens a real door to better understanding of the complicated biological phenomena. The present thesis addressed the problem of ionic penetration through biological tissue under the effect of external electric field (DC and AC). This was done by studying the diffusion coefficient D as an indicating parameter for such effects. The work was based on stochastic computer simulation of the problem such that the tissue was considered as a matrix that contains the elements under study. The size of the matrix was up to 30,000 x 30,000. Two dimensional honey comb cellular pattern was simulated such that it allowed six maximum possible element-to-element communications. The diffusants were let to diffuse under different electric field strengths in DC forward and opposite directions, and AC field with different frequencies. The effect of vacancies concentration and annealing time were tested in the absence of electric field. Two different vacancies concentrations were studied under the effect of electric field. Fist, 90% of the tissue was vacant and subjected to DC and AC fields as well as zero field. Second, 50% of the tissue was vacant and investigated under similar conditions. The results showed that for the 90% case, the penetration increased with increasing of electric field strength. While in the 50% case, the penetration increases with increasing the current until a point at which the diffusion is hindered. The DC results of forward current were compared to that of backward direct current and the results showed that the backward direction hindered diffusion. The effect of alternating current shows that penetration was inversely proportional with the frequency which agrees with literature. Comparisons of the effects of sinusoidal and square waves were illustrated. The square waves showed to have more ionic penetration and diffusion coefficient values than the sinusoidal ones. As the frequency of alternating current is decreased, its effect on diffusion became close to that of direct current. Despite the fact that the results obtained by simulation are in essence virtual and based on arbitrary units, yet the effects were clear and indicative

A computational fluid dynamics study on different solar chimney designs on solar radiation

The solar chimney power plant (SCPP) is a hopeful solution to produce electrical power from solar energy. In this paper, a 2D numerical study is presented to estimate the performance of the SCPPs while varying the collector angle, chimney diverging angle, variable solar radiation and ambient temperature and some geometrical designs. Numerical models run with solar load discrete ordinates (DO) and realizable k-ɛ turbulence models. System is defined by the collector height =50 mm, the chimney diameter =160 mm, the collector diameter =2750 mm and the chimney height =3000 mm. its investigated for each case the profile of magnitude velocity, air temperature, pressure, incident radiation and turbulence characteristics were presented. The effective choice of the best geometry is based on the maximum value of the air velocity inside the SCPP. Results indicates that a negative collector-roof positively increases the air velocity, and the output power. To a specific limit, increasing the diverging angle of the chimney has a god effect on the velocity magnitude and the other parameters. also Increasing the collector diameter and chimney height and diameter has a great effect on power output as shown in results

Evaluation of ERG-11 gene expression in azole resistant Candida isolates from various clinical specimens in ICUs

Background: Candida infection is considered one of the most dangerous infections in intensive care unit patients (ICU). Resistance to azoles is a major challenging condition in treating candida infections. Mutations or overexpression of the ERG 11 gene may contribute to azoles resistance. Methods: This prospective study evaluated 300 clinical samples including sputum, blood, urine, wound swabs, and pus obtained from different ICU patients. Different candida species were identified phenotypically by conventional methods and biochemical analysis by API 20 C kit (api® Candida) and confirmed by VITEK 2 compact system using identification yeast ID-YST cards. Antifungal susceptibility testing was performed using the VITEK 2 compact system followed by detection of ERG11-2 gene overexpression by RT-PCR in azoles resistant candida species. Results: A total of 165 candida species were detected from 300 clinical samples. C. albicans was identified in 59.4%. Most of C. albicans and non albicans were isolated from sputum samples. Only 17% of the overall isolated Candida species were resistant to fluconazole while 5% were resistant to voriconazole. Overexpression of the ERG11 gene was detected only in 10 isolates. Conclusion: Increased ERG11 gene expression may be one of the leading causes of azoles resistance among candida species in ICU patients.Background:Candida infection is considered one of the most dangerous infections in intensive care unit patients (ICU). Resistance to azoles is a major challenging condition in treating candida infections. Mutations or overexpression of the ERG11 gene may contribute to azoles resistance. Methods: This prospective study evaluated 300 clinical samples including sputum, blood, urine, wound swabs, and pus obtained from different ICU patients. Different candida species were identified phenotypically by conventional methods and biochemical analysis by API 20 C kit (api® Candida) and confirmed by VITEK 2 compact system using identification yeast ID-YST cards. Antifungal susceptibility testing was performed using the VITEK 2 compact system followed by detection of  ERG11-2 gene overexpression by RT-PCR in azoles resistant candida species.Results: A total of 165 candida species were detected from 300 clinical samples. Candida albicans (C. albicans) was identified in 59.4%. Most of C. albicans and non albicans were isolated from sputum samples. Only 17% of the overall isolated Candida species were resistant to fluconazole while 5% were resistant to voriconazole. Overexpression of the ERG11 gene was detected only in 10 isolates. Conclusion: Increased ERG11 gene expression may be one of the leading causes of azoles resistance among candida species in ICU patients

Investigating Postpartum Depression in Southern Rural Egypt and Effects of Sertraline on Fsh and Lh Gene Expression on Fathead Minnows Using Rt-pcr

Postpartum depression (PPD) is a major health problem that affects many women worldwide. In Egypt, PPD is neglected despite the expected high prevalence rate among women during the transition period after the Egyptian revolution. This research investigated the prevalence, risk factors, and interventions of postpartum depression in southern rural Egypt. Interviews were conducted with 57 participants recruited from public and private hospitals. Questionnaires and the Arabic version of the Edinburgh Postnatal Depression Scale were administered. The prevalence of PPD is 73.7%. PPD is associated with low income and age at childbirth. Most participants regarded screening mothers after childbirth for PPD as effective; in comparison to, antidepressants that were regarded by most participants as ineffective. Women in southern rural Egypt prefer high number of pregnancies, so investigating the influence of sertraline, an antidepressant medication, on female hormones becomes important. In this research, fathead minnows were exposed to 3 and 10 ppb sertraline for 7 days. Real-time Polymerase Chain Reaction was used to detect the change in gene expression of the Follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Results showed that a down regulation at the 10 ppb was evident on the LH and to a lesser extent on FSH. Our results increased levels of sertraline inhibited GnRH which influenced expression of LH and FSH

Computational fluid dynamics study on a solar chimney with different ground materials

The problem of energy source depletion with the restricted regulation about the emissions make the need for another alternative sours of energy is a worldwide demands. The solar chimney power plant (SCPP) is an optimistic solar energy technology that produces electrical power. In this paper, a 2D analytical study is offered to evaluate the working of the SCPPs’ performance with the varying ground material. Sand, concrete, asphalt, and saturated sand will be used as absorber materials in this study. The Numerical model was done with the realizable k-ɛ turbulence model and the discrete ordinates (DO) solar load model. The model\u27s chimney diameter is 200 mm, collector diameter is 3000 mm, and chimney height is 3500 mm. The model\u27s collector height is 70 mm. It gave the magnitude velocity contour, moving air temperature, pressure, and turbulence characteristics for each unique case. Based on the highest air velocity value inside the SCPP and the resulting power output, the optimal material is chosen

Experimental Investigation on a Slurry Pump at Different Operating Parameters

Study on slurry pump performance has attracted much interest in many engineering fields. When pumps are required to handle slurries. The pump head and efficiency are mainly affected by the solid size, solid concentration and solid density. Centrifugal slurry pumps are benign used extensively for pipeline transportation systems and phosphate extraction industry because of their capabilities to economically convey large size abrasive solids in bulk. There is a lack of information about the effect of slurry on the performance characteristics of conventional centrifugal pumps when working without and with cavitation. A test rig with a testing centrifugal pump was constructed. The suction pipe between the mixing tank and pump inlet was designed to avoid solid deposition in suction pipe and to keep the pressure loss between the sump and the pump as low as possible. The rig was designed so that the flow rates, suction pressure, rotational speed, and solid concentration could be varied independently. The results showed that the head generating capability and pump efficiency decrease, also the power consumption increases with increasing solid concentration, consequently the head and efficiency of the pump with NPSH decreases with increasing the solids concentration and particle size, and cavitation inception accelerates with increase the solid concentration

Interaction of nanoscale particles with the skin barrier

Skin penetration of nanoparticles was the focus of several recent studies. This is of major importance in basic research for potential future applications, e.g. designing topical and transdermal delivery systems, as well as for health risk analysis. Yet, there is a controversy among researchers on the status of their skin penetration due to different experimental setups. Meanwhile, there is little known about the mechanism and determinants of nanoparticle penetration. The main thesis objective was hence to study the penetration of model gold nanoparticles of different physicochemical and formulation parameters through human skin of different degrees of barrier integrity. Multiphoton microscopy was used for nanoparticle detection. Imaging parameters were determined in terms of resolution and depth profiling of gold nanoparticles in skin. A semiquantitative approach based on pixel analysis of gold nanoparticles was developed to compare nanoparticle localization in different skin locations under different conditions. Based on penetration experiments, determinants that favor or limit particle penetration were determined as well as the barrier to penetration (intercellular lipids). Finally nanoparticle penetration was successfully enhanced using a chemical enhancement approach. Results obtained are important to enhance our understanding of nanoparticle interaction with the skin barrier. Future studies are required to reduce the gap between research and applications.Die Penetration von Nanopartikeln ist Gegenstand der aktuellen Forschung. Diese Frage ist von großer Bedeutung für die Anwendung im Bereich der Nanomedizin als auch für die Abschätzung des Risikopotenzials bei Kontakt mit solchen Systemen. Bis dato sind allerdings keine eindeutigen Aussagen möglich. Das Ziel dieser Arbeit war daher die Untersuchung des Penetrationsverhaltens anhand von kolloidalem Gold (AuNP). Dieses Modellsystem erlaubt die Untersuchung der Penetration in Abhängigkeit von verschiedenen physikochemischen Eigenschaften der Partikel (oberflächenmodifiziert), als auch von Formulierungseigenschaften (Vehikel). Die AuNP erlauben eine Visualisierung mittels Multiphotonen Mikroskopie. Daher wurden die Auflösung und die optischen Parameter für AuNP in Haut bestimmt. Des Weitern wurde ein Pixel-basiertes Verfahren ermittelt, das eine semiquantitative Analyse der penetrierten Objekten ermöglicht. Dies erlaubt eine Abschätzung der Partikelpenetration. Penetrationsexperimente erlaubten die Parameter, die die Penetration beeinflussen, hinsichtlich Größe und Oberflächenpolarität einzuschränken. Außerdem konnte gezeigt werden, dass auch die Penetration von Nanopartikeln mit Hilfe von Penetrationsverbesserern gesteigert werden kann. Die Ergebnisse dieser Arbeit sind wichtige Bausteine für das Verständnis der Interaktion von Nanopartikeln mit der Hautbarriere. Zukünftige Studien sind dennoch nötig, um die Lücke zwischen Forschung und möglicher Anwendung zu schließen

Utilization of Ammonia Hydroxide /Diesel Fuel Blends in Partially Premixed Charge Compression Ignition (PPCCI) Engine: A Technical Review

Almost 50% of new car registrations in Europe at the turn of the century were diesel. However, reports of harmful NOx emissions have been corroborated by diesel emissions scandals, which have sent the diesel engine market into a tailspin and raised concerns about the diesel engine\u27s long-term viability. Developing of diesel cars with low NOx emissions has been announced by major automakers. Modern posttreatment systems can be installed, and they will result in decreased NOx emissions for heavy-duty, marine, or power production applications. Despite attempts to lower NOx emissions, the automobile, marine, and power generation industries must decarbonize if we are to reach greenhouse gas emission objectives and prevent global warming. Using fuels with low carbon, like ammonia, can help decarbonize a diesel engine. Using ammonia as a fuel for diesel engines is discussed at length in this work. To drastically lower carbon emissions, Ammonia could be burned when mixed with diesel or another low-temperature fuel in a dual-fuel system. Creating advanced injection technologies can improve overall emissions while also improving performance. However, due to the coupling of nitrogen to the fuel, dual fuel combustion of ammonia currently has relatively large emissions of ammonia and nitrogen oxides. As a result, post-processing mechanisms need to be put in place. With the introduction of modern combustion systems like HCCI, PCCI, and RCCI systems, ammonia is currently only a practical alternative in specific applications including maritime, power generating, and maybe heavy duty

Impact of Utilizing a Diesel/Ammonia Hydroxide Dual Fuel on Diesel Engines Performance and Emissions Characteristics

The problem of global warming and environmentally polluting emissions has become the call of the times. To solve this problem, the trend to change or share new types of fuel has become a new way to solve this problem. One of the most promising types of fuel in the future is ammonia, as it is a carbon-free fuel, unlike traditional fossil fuels. Because of the danger of using ammonia as a gas, it was safer to use ammonia as a liquid. In this study, ammonia hydroxide was used as a proportion with diesel fuel in a PCCI diesel engine. The diesel engine is a single-cylinder, four-stroke engine. Ammonia hydroxide fuel with a ratio of 33% ammonia-water by volume was used with diesel fuel. The experiment was carried out with ammonia hydroxide ratios of 2.5%, 5%, 7.5%, and 10%, respectively. The results of emissions, thermal efficiency (BTE), fuel consumption (BSFC) and exhaust temperatures were compared. It was concluded that using ammonia hydroxide ratios to diesel led to an increase in thermal efficiency by 23.5% compared to diesel only by 20.5%, and fuel consumption was also reduced. 391.083g/Kw.h compared to diesel is only 455.56 g/Kw.h. As a result of the presence of ammonia hydroxide, exhaust temperatures are lower than when using diesel only. Therefore, this study discusses with practical experience the effect of using ammonia hydroxide with diesel on the performance and efficiency of the engine and fuel emissions characteristics

Impact of Utilizing a Diesel/Ammonia Hydroxide Dual Fuel on Diesel Engines Performance and Emissions Characteristics

The problem of global warming and environmentally polluting emissions has become the call of the times. To solve this problem, the trend to change or share new types of fuel has become a new way to solve this problem. One of the most promising types of fuel in the future is ammonia, as it is a carbon-free fuel, unlike traditional fossil fuels. Because of the danger of using ammonia as a gas, it was safer to use ammonia as a liquid. In this study, ammonia hydroxide was used as a proportion with diesel fuel in a PCCI diesel engine. The diesel engine is a single-cylinder, four-stroke engine. Ammonia hydroxide fuel with a ratio of 33% ammonia-water by volume was used with diesel fuel. The experiment was carried out with ammonia hydroxide ratios of 2.5%, 5%, 7.5%, and 10%, respectively. The results of emissions, thermal efficiency (BTE), fuel consumption (BSFC) and exhaust temperatures were compared. It was concluded that using ammonia hydroxide ratios to diesel led to an increase in thermal efficiency by 23.5% compared to diesel only by 20.5%, and fuel consumption was also reduced. 391.083g/Kw.h compared to diesel is only 455.56 g/Kw.h. As a result of the presence of ammonia hydroxide, exhaust temperatures are lower than when using diesel only. Therefore, this study discusses with practical experience the effect of using ammonia hydroxide with diesel on the performance and efficiency of the engine and fuel emissions characteristics