140 research outputs found
Development of a hybrid power management unit for mobile applications: solar energy case study
Applying photovoltaic power to mobile devices has become a hot area of research due to the availability of solar energy. Usage of photovoltaic as the power source for mobile devices will enhance device performance. There are many challenges to interface photovoltaic energy to mobile loads such as variation of power coming out from photovoltaic panels, unregulated voltage and limited power. Maximum power point tracking (MPPT) is used in photovoltaic systems to maximize the photovoltaic array output power under environmental variations such as irradiation and temperature for mobile applications. A power management system is proposed to apply photovoltaic harvested energy effectively to mobile or handheld devices while running workloads. The proposed system mainly consists of a MPPT block and a Power Distribution Control Unit (PDCU). The PDCU allows usage of an AC/DC external in case of insufficient photovoltaic power in order to maintain the load running. Different cases of operation are handled by the PDCU unit depending on the availability of photovoltaic power, load power, battery state of charge and existence of the AC/DC external. In addition, a new MPPT algorithm is proposed to provide fast and accurate tracking. Analysis and simulation results are provided to demonstrate system functionality and performance sensitivity. Moreover, a prototype of the proposed system is still under progress, to verify the possibility of building such system
Spinal release of tumour necrosis factor activates c-Jun N-terminal kinase and mediates inflammation-induced hypersensitivity.
BackgroundMounting evidence points to individual contributions of tumour necrosis factor-alpha (TNF) and the c-Jun N-terminal kinase (JNK) pathway to the induction and maintenance of various pain states. Here we explore the role of spinal TNF and JNK in carrageenan-induced hypersensitivity. As links between TNF and JNK have been demonstrated in vitro, we investigated if TNF regulates spinal JNK activity in vivo.MethodsTNF levels in lumbar cerebrospinal fluid (CSF) were measured by enzyme-linked immunosorbent assay, spinal TNF gene expression by real-time polymerase chain reaction and TNF protein expression, JNK and c-Jun phosphorylation by western blotting. The role of spinal TNF and JNK in inflammation-induced mechanical and thermal hypersensitivity was assessed by injecting the TNF inhibitor etanercept and the JNK inhibitors SP600125 and JIP-1 intrathecally (i.t.). TNF-mediated regulation of JNK activity was examined by assessing the effect of i.t. etanercept on inflammation-induced spinal JNK activity.ResultsTNF levels were increased in CSF and spinal cord following carrageenan-induced inflammation. While JNK phosphorylation followed the same temporal pattern as TNF, c-jun was only activated at later time points. Intrathecal injection of TNF and JNK inhibitors attenuated carrageenan-induced mechanical and thermal hypersensitivity. TNF stimulation induced JNK phosphorylation in cultured spinal astrocytes and blocking the spinal actions of TNF in vivo by i.t. injection of etanercept reduced inflammation-induced spinal JNK activity.ConclusionsHere we show that spinal JNK activity is dependent on TNF and that both TNF and the JNK signalling pathways modulate pain-like behaviour induced by peripheral inflammation
Assessment phenotypic diversity of rice (Oryza sativa L.) genotypes by multivariate analysis
An efficient way to achieve superior productivity is to determine the genetic variation of the various rice genotypes. This research was aimed at estimating potential variations between rice genotypes and identifying each trait contribution in total variation and classifying superior genotypes. The experiment was performed at the Rice Research and Training Centre, Sakha, Kafr El-Sheik, Egypt. Twenty-two genotypes of rice were analyzed using seven agronomic traits. Multivariate approaches were utilized including principal components and cluster analysis. Results showed that PC1 and PC2 represented 66.1% of the variation between studied genotypes, mainly 48% because of grain yield per plant variation in PC1 followed by the characteristics of its components i.e., number of panicles per plant, number of filled grains per panicle, and 1000-grain weight. The three Egyptian rice genotypes Giza 181, Giza 178, and Giza 177 were the best genotypes for grain yield. Cluster results revealed that the majority of genotypes originated from one source (except for Indian variety IET1444) or belonged to one classification were clustered together. Multivariate analytical approaches are ideal instruments for providing information on agronomic character variations. Consequently, the results of the current study should be taken into account when developing new rice varieties.
 
Assessment of Natural Radioactivity Levels and Some Associated Radiological Hazards of Portland Cements and Their Raw Materials from Selected Cement Industries in Eastern Uganda
The radiological hazards as a result of the natural radionuclides 238U, 232Th and 40K for Portland cement from different factories were assessed using HPGe detectors. The measured mean activity concentrations for 238U, 232Th and 40K were; 50.34±1.86, 38.01±1.48 and 331.59±13.19 Bq/kg respectively for the Portland cement raw materials, 31.15±1.49, 20.83±1.02 and 267.60 ± 8.65 Bq/kg respectively for the Portland cement products. The radium equivalent activity (Raeq), Excess lifetime cancer Risks (ELCR), external and internal hazard indices were also estimated due to the Portland cement and the respective raw materials and the results obtained were comparable to others cited. The results obtained in this study therefore indicate no significant radiological hazard that may arise from the use of these materials in construction of dwelling places. Keywords: Natural Radioactivity levels, Portland cement, MCNP, Gamma spectroscopy DOI: 10.7176/JEES/13-6-03 Publication date:August 31st 202
Modification of montmorillonite and its effect on the thermal stability of PP/APP
149-156The effect of montmorillonite (Mt) and the treated montmorillonite (MtT) with sulfuric acid on the efficiency of nanoparticles
of ammonium polyphosphate (APP) has been studied. Five samples containing different percentage of
montmorillonite are prepared and other five samples containing treated montmorillonite also prepared. The chemical
analysis (XRF), the spectroscopic measurements (XRD and IR) and the morphology (SEM) studied have been performed to
identify the sulfuric acid treatment for the montmorillonite on the chemical composition and on the structure of the
montmorillonite layers. The results have been revealed that the acid treatment changes the layered structure of
montmorillonite and no effects on the chemical composition. The thermogravimetric analysis (TGA) is used to evaluate the
ammonium polyphosphate (APP)/ montmorillonite (Mt) or APP/ montmorillonite treatment (MtT) as flame retardants for
Polypropylene (PP). The results show that both treated and untreated montmorillonite when mixed with APP accelerate the
first step of the thermal degradation. Also, it is indicated that the time of degradation increased by adding treated or
untreated montmorillonite to APP in the following sequence PP<PP/APP<PP/(APP/Mt)<PP/(APP/MtT). Overall, the results
indicated that the modification of added montmorillonite to App improves the flammability of the PP
Defining the Innate Immune Responses for SARS-CoV-2-Human Macrophage Interactions
Host innate immune response follows severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and it is the driver of the acute respiratory distress syndrome (ARDS) amongst other inflammatory end-organ morbidities. Such life-threatening coronavirus disease 2019 (COVID-19) is heralded by virus-induced activation of mononuclear phagocytes (MPs; monocytes, macrophages, and dendritic cells). MPs play substantial roles in aberrant immune secretory activities affecting profound systemic inflammation and end-organ malfunctions. All follow the presence of persistent viral components and virions without evidence of viral replication. To elucidate SARS-CoV- 2-MP interactions we investigated transcriptomic and proteomic profiles of human monocyte-derived macrophages. While expression of the SARS-CoV-2 receptor, the angiotensin-converting enzyme 2, paralleled monocyte-macrophage differentiation, it failed to affect productive viral infection. In contrast, simple macrophage viral exposure led to robust pro-inflammatory cytokine and chemokine expression but attenuated type I interferon (IFN) activity. Both paralleled dysregulation of innate immune signaling pathways, specifically those linked to IFN. We conclude that the SARS-CoV-2-infected host mounts a robust innate immune response characterized by a pro-inflammatory storm heralding end-organ tissue damage
Validity of sphenoid ostium in relation to posterior wall of maxillary sinus by computed tomography
Background: Sphenoid sinus is the most inaccessible paranasal sinus, enclosed within the sphenoid bone and intimately related to numerous vital neural and vascular structures. Anatomic variation of the sphenoid sinus is well documented and may complicate surgery in such a place.Objective: To assess the reliability of preoperative computed tomography (CT) in determination of the distance between the posterior wall of maxillary sinus (PWMS) and the sphenoid sinus ostium (SSO) in the coronal plane.Patients and methods: This was a prospective study of the distance between the SSO and the PWMS in the coronal plane, which was measured both radiologically in preoperative CT and intraoperatively during endoscopic sinus surgery for patients in need for middle meatal antrostomy and sphenoid sinusotomy at the same side. Distances obtained by both techniques have been tested for the degree of correlation. Number of the included patients was 25.Results: Forty four nasal sides were included in the study. The mean distance between the sphenoid sinus ostium and posterior wall of maxillary sinus in the coronal plane was 6.6 ± 1.8 mm when measured by preoperative CT and 6.9 ± 1.9 mm when measured directly during surgery. No significant difference was found between the mean distances measured by both techniques (p = 0.246) with good agreement between them (r = 0.864).Conclusion: Preoperative CT may be a reliable tool to preoperatively determine the difference in depth between the PWMS and the SSO
THE IMPACT OF RELIGIOUS TOURISTS’ SATISFACTION WITH HAJJ SERVICES ON THEIR EXPERIENCE AT THE SACRED PLACES IN SAUDI ARABIA
To identify the impact of satisfaction with the provided services (food quality, transportation, accommodation, medical
services and the religious guidance) on the spiritual experience of religious tourists, as well as the potential moderating role of
pilgrims’ demographic characteristics on the relationship between service satisfaction and experience. A structured survey was
distributed among the domestic pilgrims in Mecca, Saudi Arabia who performed Hajj under the control of three licensed
agencies. Results showed that the satisfaction with transportation services and religious guidance were independent antecedent
predictors of the spiritual experience. Furthermore, pilgrims’ age had significantly moderated the relationship between
satisfaction with medical services and experience. National authorities can effectively improve the spiritual experience by
providing comfortable means of transportation and reliable religious scholars to guide the pilgrims at different sacred destinations
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