296 research outputs found
Site-specific ground motion modeling for a historical Cairo site as a step towards computation of seismic input at cultural heritage sites
No full textThroughout time, the area of historical Cairo has been affected by several earthquakes from near and distant seismogenic zones. The maximum earthquake intensity reported in Cairo is VII, on the Modified Mercalli Intensity scale, due to the 1992 Cairo earthquake (Mw=5.9). About 212 Coptic and Islamic monuments were damaged. The spatial distribution of damage, suggests the occurrence of strong local site effects in combination with high vulnerability of the cultural heritage buildings. This study presents the application of a novel seismic hazard analysis approach at a local scale based on physics-based ground motion simulations. A site-specific multi-scenario seismic input (ground motion time histories and response spectra) is computed at a heritage building in Cairo, considering the local site effect. The seismic input is calculated in three steps: a regional scale analysis followed by a site-specific analysis and the combinations of the computed scenarios ground motion. In the regional scale analysis synthetic accelerograms are computed at the site bedrock. Then, the site-specific analysis is performed to calculate the site surface ground motions or response spectra considering the local site effect. Three earthquake scenarios have been considered, characterized by different locations, magnitudes, and fault configurations. The last step consists in the combination of the computed scenario ground motion into one single multi-scenario seismic input specific for the site of interest. This input is represented by spectral ordinates and their variability. For the engineering purpose of time history analysis, the method allows also to extract the computed site specific physics-based accelerograms, requiring no amplitude scaling nor filtering by magnitudes, distances, or site classifications, as usually done with real ground motion records
The relationship between self-efficacy beliefs and social-emotional competence in at-risk girls
No full textLittle is known about the relationship between self-efficacy beliefs and social-emotional competence in ethnic minority middle school girls. These children face a number of challenges related to their minority status, peer relationships, school transition, and entry into adolescence. School psychologists have attempted to increase the chances of success among this population by trying to build their resilience. Unfortunately, there is little prior research on the relationship between protective factors such as self-efficacy, optimism, social skills, and pro-social classroom behaviors for this unique population. A goal of this study was to generate data that would appropriately inform social and emotional interventions. This study examined the relationship between self-efficacy beliefs and social-emotional competence in 16 at-risk 7th and 8th grade students over the course of one school year. A cross-lagged panel design determined the trajectory of change among self-efficacy beliefs and social-emotional competence variables over time. Crosstab and chi-square analyses examined relationships among variables on an individual level. The strongest relationships were found among the same variables over time, indicating that interventions should focus on a single skill set of concern for the greatest improvement in that skill set over time. Some data suggest a relationship between optimism and social-emotional competence, which would indicate that optimism interventions may be helpful in improving social-emotional competence for this population. Optimism may be necessary but not sufficient for improvement in social-emotional competence. Future research may benefit from examining these relationships across a longer period of time and examining how different cultural variables may impact our understanding of the relationship between self-efficacy beliefs and social-emotional competence.Psy. D.Includes bibliographical referencesby Heather M. Hame
Polyphenolic profile, hepatoprotective evaluation, and molecular docking study of three palm tree species (Family Arecaceae)
No full textArecaceae species are renowned in traditional medicine for treating inflammation and liver disorders. Herein, we aimed to identify the phenolic constituents and the hepatoprotective potential of the aqueous methanol extract (AME) of Aiphanes
eggersii, Carpoxylon macrospermum, and Jubaeopsis caffra leaves, in a drug-induced liver injury in vivo model. The AMEs are considered safe until the maximum tested dose (5 g/kg). The two selected screening doses, 500 and 1000 mg/kg, displayed antioxidant activity with significant (P < 0.05) decline in the liver/body weight ratios (19.1–29.7%), liver enzymes (25.9–63.4%), and malondialdehyde (39.3–63.8%), while increasing reduced glutathione (2.1–3.2 folds) and superoxide
dismutase (2.2–3.1 folds). Moreover, they demonstrated a significant anti-inflammatory effect (P < 0.05) with decline in NF-KB p65 (32.7–64.5%), tumor necrosis factor-alpha (24.9–64.4%), and interleukin-1β (18.7–64.2%). Ultimately, significant (P < 0.05) antiapoptotic effects from the declined BAX (31.8–65.6%) and caspase-3 (23–69%), while increasing Bcl2 (2.7–5.7 folds). Ultimately, the histopathological investigation showed obvious hepatoprotective efficacy. The HPLC–MS/MS profiling revealed high phenolic content. As key phenolic attributes, chlorogenic acid is major in C. macrospermum and J. caffra, while vanillic in A. eggersii. Rutin is the principal flavonol in the three extracts (365.852–57970.205 μg/Kg), followed by hyperoside (62.764–7379.297 μg/Kg) and hesperidin (1225.976–1575.550 μg/Kg). The docking results show that rutin and hesperidin achieved the best fitting to SOD-1, with binding scores of -8.24 and -8.36 kcal/mol, while -8.0671
and -7.1735 kcal/mol with caspase-3, respectively with stable conformations revealed by 100 ns MD. In all, the investigated species exert significant hepatoprotective activity, at least partly, to their constitutive flavonoids and phenolic acids. However, further clinical investigation is still needed
The performance enhancement of solar cooker integrated with photovoltaic module and evacuated tubes using ZnO/Acalypha Indica leaf extract: response surface study analysis
No full textIn this study, the effect of employing ZnO/Acalypha Indica leaf extract (ZAE) on the energy absorption of a coated portable solar cooker has been examined using an experimental setup. A prototypical model has been developed to corroborate in associating an investigative outcome per constituents of the experiments. The studied heat transfer process in ZAE is stable for harsh conditions. The design analysis and an estimation of the system performance were done given various parameters including the pressure of the vacuum envelope, bar plate coating digestion, emissivity, and solar rays. The fabricated solar was tested with and without ZAE to investigate the impact of this coating material on the solar cooker's thermal performance. To observe the performance of the new design, two figures of merit (F-1 and F-2) have been introduced. The factual food cooking assessments were for a family of four people, which operated in ZAE coating (0.8, 1.0, 1.2 mu m) of the solar cooker. The values of F-1 and F-2 for the proposed cooker were obtained as 0.1520 and 0.4235, respectively, which is intact with the BIS values. The results revealed that employing ZAE instead of a thermal NHC-PV solar cooker reduced the time required to boil 2 L of water for about 47 min. The overall thermal energy productivity of the solar cooker with electrical backup was obtained as 42.65%, indicating that the ZAE coating can improve the thermal efficiency by 10.35%
Mechanisms of chemotherapeutic resistance in glioma: mathematical modeling and gene expression profiling
No full textGliomas are refractory to chemotherapy because of acquired resistance, which is associated with changes in important cellular processes, such as cell cycle kinetics and cell death. The mechanistic relationship between resistance markers and failure of chemotherapy remains to be elucidated. To that end, identification of biological systems and their interactions is of great promise. We characterized the pharmacological response of glioma cell lines to chemotherapeutic drugs, carmustine and etoposide. We developed a cell cycle structured mathematical model that reproduces the dynamics of dose response of cells to the two chemotherapeutic agents based on two parameters relating to cell cycle arrest and cell death. We have shown that the model can provide a quantitative distinction between the influence of these two processes on tumor cells simply from pharmacological dose response curves, from which mechanism is not obtained using traditional analyses. The model suggests that carmustine elicits its effect via cell death, while etoposide primarily induces cell cycle arrest. We have also applied this methodology to track acquisition resistance to chemotherapy. We have generated a panel of glioma cell lines resistant to carmustine by incremental stepwise exposure to sublethal doses of the drug. To characterize molecular events underlying response of resistant and parent cell lines to carmustine, we performed gene expression profiling using micaroarrays followed by functional network analysis. We found that NFκB activation is implicated in the response to carmustine, and resistant cells exhibit increased survival mediated by inflammatory responses. In addition, resistant cells induce genes promoting cell cycle arrest and repress genes implicated in cell cycle phase transitions and proliferation. In agreement with gene expression results, we found that resistant cells exhibit decreased cell death and rapid and efficient arrest. We have characterized the DNA repair capacity, which is known to modulate cell cycle arrest and apoptosis. Our results provide insights into molecular pathways involved in resistance to carmustine in vitro. If they prove to hold for gliomas in human patients, these results can point the way towards improved therapeutic regimens that act upon NFκB mediated cell survival module in concert with cell cycle checkpoint abrogators.Ph.D.Includes abstractVitaIncludes bibliographical referencesby Salaheldin S. Hame
The immunomodulatory roles of small heterodimer partner and their implications in breast cancer progression
No full textLimitedBreast cancer remains the second cancer-related cause of death among women. With limited therapeutic options for metastatic disease, immune checkpoint blockade (ICB) was anticipated to provide a novel treatment strategy. However, the efficacy of ICB in breast cancer has been limited, in part due to the highly immunosuppressive tumor microenvironment (TME); myeloid cells and regulatory T (Treg) cells being known contributors. Nuclear receptors have been implicated in the regulation of myeloid cells. Therefore, we evaluated this superfamily, and found that higher tumoral SHP expression was associated with favorable prognosis for patients. Thus, we hypothesized that SHP modulates the TME to lower breast cancer progression. Using genetic and pharmacological approaches, we evaluated the immune and anti-cancer function of myeloid cell-expressed SHP. We found that SHP within mouse and human myeloid cells skews T cell expansion away from Tregs, resulting in more robust effector T (Teff) cell responses. Furthermore, a small-molecule agonist of SHP, DSHN, lowered Tregs in antigen-tolerized mice. Using the MMTV-PyMT model of mammary cancer, it was found that tumor growth was increased in mice lacking SHP (SHP-/-). Transcriptomic analysis of these tumors indicated an enriched suppressor T cell activity in the absence of SHP. Indeed, flow cytometry analysis indicated increased infiltration of myeloid cells and Tregs, with a concomitant decrease in Teffs. In further support for a role of myeloid cell-expressed SHP, syngeneic mammary cancer grafts grew faster in mice with SHP specifically knocked down in the myeloid lineage (LysMCre;SHPfl/fl). Importantly, treatment of mice with DSHN decreased growth of tumors and metastatic lesions in mice, highlighting the potential clinical translation of these findings. SHP expression within myeloid cells results in decreased expansion of Treg cells, ultimately altering the TME to promote immune anti-cancer activity. Our work reveals a novel mechanism to lower immunosuppression of solid cancers, which will likely enhance the efficacy of standard ICB therapy.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-12-01The student, Sayyed Hamed Shahoei, accepted the attached license on 2020-11-22 at 19:58.The student, Sayyed Hamed Shahoei, submitted this Dissertation for approval on 2020-11-22 at 20:19.This Dissertation was approved for publication on 2020-11-29 at 14:07.DSpace SAF Submission Ingestion Package generated from Vireo submission #15934 on 2021-03-04 at 16:32:13Made available in DSpace on 2021-03-05T21:45:34Z (GMT). No. of bitstreams: 2
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Non-Homogeneous Sampling Rate Wide Area Backup Protection using Synchrophasors and IED Data
No full textFault currents may result in cascading failures and even system collapse if not detected and cleared on time. To account for the possibility of failure of primary protection under stressed system conditions, an extra layer of protection is commonly employed, referred to as backup protection. This paper introduces an effective formulation for realizing remote backup protection using available data from PMUs and Intelligent Electronic Devices (IEDs). The proposed method is split into three main stages. The first stage deals with the zoning detection of the fault. The second stage is aimed at faulted line detection, and finally, the third stage determines the fault distance on the faulted line. The method is designed to take full advantage of measurements provided by PMUs and IEDs. The challenges associated with different reporting rates are resolved thanks to the dynamic decimator employed to this end. The proposed method has been implemented in real-time by applying co-simulation with MATLAB and validated using the New England IEEE 39 bus system with several fault events.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent Electrical Power Grid
Interfacial conduction in organic ferroelectric memory diodes
No full textSolution-processed memory diodes based on phase separated blends of ferroelectric and semiconducting polymers in the low resistance on-state operate similar to a vertical field-effect transistor at the pinch-off. Numerical simulations have shown that the performance of the diode is dominated by the conduction of charge carriers at the interface between the semiconductor and ferroelectric phases. Here, we present an unambiguous experimental demonstration of the charge injection process in the diodes. We employ a modified diode structure, wherein the electrode in contact with the semiconductor phase has been intentionally removed. Even in the absence of an electrical contact with the semiconductor phase, the diode still shows resistance switching. We provide numerical simulations that reproduce the experimentally measured I-V characteristics and therefore confirm interfacial conduction in the diodes. Furthermore, we discuss the implications of the proposed memory structure particularly in the performance of light-emitting diodes with built-in memory functionality, i.e., MEMOLEDs.Novel Aerospace Material
Mapping and evaluating the condition of artificial levees
No full textArtificial levees along alluvial rivers are major components of flood risk mitigation. This is especially true in the case of Hungary, where more than one-third of the country is threatened by floods and protected by an over 2940-km-long levee system. Most of the levees were built in the 19th century. Since then, several natural and anthropogenic processes, such as compaction, erosion, Etc., could contribute to these earth structures' slow but steady deformation. Meanwhile, as construction works were scarcely documented, the structure and composition of artificial levees are not well known. Therefore, the present analysis aimed to use different geophysical techniques to validate their efficiency in mapping structural differences, possible compositional deficiencies, potential defects and sections where elevation decrease and compare the compositional and structural variations of two very different levee sections along a 24 km section of the River Tisza and a 24 km section of the River Maros. Investigations were conducted by real-time kinematic GPS (RTK-GPS), Ground penetrating radar (GPR), Electrical Resistivity Tomography (ERT) and drillings. Onsite data acquisition was complemented with an analysis using a Persistent Scatterer Synthetic Aperture Radar (PSI) to assess general surface deformation. The higher frequency 200 MHz GPR data have shown that levee structures can significantly vary even in a few km on sections with the same construction history.
Based on electrical resistivity tomography results with a precise analysis of grain size and their related physical parameters used for monitoring the materials of two different levee sections along the Tisza and Maros rivers, we noticed that the main components of investigated Tisza levee section are medium and fine silts, however, the situation of the investigated Maros levee section shows more variation of different materials which are fine, medium, and coarse silt, moreover, fine, medium, and coarse sand. The investigated section of the Tisza levee showed low resistivity values, indicating the fine-grained materials' conductivity. In contrast, the investigated section of the Maros levee showed high resistivity values, indicating the resistivity nature of higher grain size sediments forming this section, especially noticed on the protected side of the levee.
It was possible to capture structural changes and resolving the thin layers by 1 m electrode spacing ERT profile. In turn, at a larger spacing it was possible to get information on the sedimentary base below the levee body. The selected levee section could be assessed in terms of its structure and composition and major units within the levee body and their composition could be resolved by the applied methods.
In general, there is a similarity in the materials and their resistivity range which form the core of Tisza and Maros levees, however, the situation on their both sides is not the same. Regarding the analysis of different physical properties of the two levee systems like resistivity, porosity, density, water content, grain size, and saturated hydraulic conductivity, the materials of the Maros levee could be distinguished well and showed more variation when it is compared to the materials of Tisza levee. It means that the physical properties of levee materials are very important, and they are recommended when carrying out further levee investigations.
From the physical properties mentioned above, it was found that some of them show a connection with resistivity except hydraulic conductivity parameter that did not show a direct connection, however the latter could exhibit the aquitard nature of Tisza levee materials and the non-aquitard nature of Maros levee materials which illustrates the difference in levee composition in terms of flood risk or flood safety.
Based on height measurements, the mean elevation of the levee crown decreased by 8 cm in a 40-year time span. However, elevation decrease could reach up to 30 cm at some locations. Sections affected by structural anomalies, compositional changes, and increased surface subsidence are especially sensitive to floods when measurement results are compared to flood phenomena archives.
GPR profiles showed several anomalies, including structural and compositional discontinuities and local features. They were classified into six types regarding to the flood risk; tensile cracks (enables piping, leading to levee breach or mass failure, cracks might close when the levee gets wet), remarkable changes in dielectric permittivity (enables seepage, leading to mass failure), animal burrows (enables piping, leading to levee breach or mass failure), layer deformation (results in height decrease, overtopping), paleo river channel (enables seepage below the levee, leading to water upwelling and the development of sand boils), sudden change in stratification or dipping layers (enables contour line seepage, leading to mass failure). The penetration dept
Validation platform for ultrasound-based monitoring of thermal ablation
No full textPURPOSE: A ground-truth validation platform was developed to provide spatial correlation between ultrasound (US), temperature measurements and histopathology images to validate US based thermal ablation monitoring methods.
METHOD: The test-bed apparatus consists of a container box with integrated fiducial lines. Tissue samples are suspended within the box using agar gel as the fixation medium. Following US imaging, the gel block is sliced and pathology images are acquired. Interactive software segments the fiducials as well as structures of interest in the pathology and US images. The software reconstructs the regions in 3D space and performs analysis and comparison of the features identified from both imaging modalities.
RESULTS: The apparatus and software were constructed to meet technical requirements. Tissue samples were contoured, reconstructed and registered in the common coordinate system of fiducials. There was agreement between the sample shapes, but systematic shift of several millimeters was found between histopathology and US. This indicates that during pathology slicing shear forces tend to dislocate the fiducial lines. Softer fiducial lines and harder gel material can eliminate this problem.
CONCLUSION: Viability of concept was presented. Despite our straightforward approach, further experimental work is required to optimize all materials and customize software. [ABSTRACT FROM AUTHOR]Peer reviewedFinal article publishe
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