252 Works

Investigating the Role of Lactate in Regulating Gene Expression through Epigenetic Modifications in Neuronal Cells

Manar M. Darwish
Lactate has been long thought of as a dead-end waste product of glycolysis. In the brain, recent evidence has revealed a key role of L-lactate creating a paradigm-shift in our understanding of the neuronal energy metabolism. The Astrocyte neuron lactate shuttle (ANLS) model, has shown L-Lactate as the main energy substrate delivered by astrocytes to neurons to sustain neuronal oxidative metabolism. This metabolic coupling is an essential mechanism for long-term memory formation. Experimental evidence indicates...

Performance comparison of Hierarchical Non-Terrestrial Networks for 6G

Dengke Wang
This thesis investigates the fundamental performance of Hierarchical Non-Terrestrial Networks for the 6th generation (6G). 6G communication research is currently focus- ing on non-terrestrial networks (NTNs) to promote ubiquitous and ultra-high-capacity global connectivity. Specifically, multi-layered hierarchical networks, i.e., the orches- tration among different aerial/space platforms, including Unmanned Aerial Vehicles (UAVs), High Altitude Platforms (HAPs), and satellites co-operating at different al- titudes, currently represents one the most attractive technological options to solve coverage and latency constraints...

Frequency-modulation Stimulated Raman Scattering microscopy with an Acousto-Optic Tunable Filter

Elisa Grassi
Stimulated Raman Scattering (SRS) is a Coherent Raman microscopy method that has been increasingly employed in recent years for highly-specific, label-free, and high-speed bioimaging. Compared to a similar Coherent Raman method, the so-called Coherent Anti-Stokes Scattering (CARS) microscopy, it exhibits advantages such as the absence of nonresonant background (NRB) and the linearity of the signal intensity on the concentration of molecules of interest. However, SRS can be affected by unwanted background signals that hinder the...

Zaxinone, a Natural Apocarotenoid, Regulates Growth and Strigolactone Biosynthesis in Rice

Jian You Wang
Carotenoids are the precursor of several metabolites with regulatory functions, which include the plant hormones abscisic acid (ABA) and strigolactones (SLs), and signaling molecules, such as β-cyclocitral. These carotenoid-derivatives originate from oxidative breakdown of the double bond resulting in carbonyl cleavage-products designated as apocarotenoids. The cleavage reaction causing apocarotenoid formation is catalyzed frequently by Carotenoid Cleavage Dioxygenases (CCDs). Several lines of evidence indicate the presence of yet unidentified apocarotenoids with regulatory or signaling function. Here,...

Effect of Anthropogenic Noise on Reef Macroinvertebrates (Lambis lambis and Tridacna maxima)

Michelle-Nicole Havlik
Boat noise has been shown to distract and cause harm to many marine organisms. Most of the study effort has been focused on fish & marine mammals, even though invertebrates represent 99% of all living organisms, both terrestrial and aquatic. The small amount of studies conducted on invertebrates have demonstrated a clear negative correlation between anthropogenic noise pollution and invertebrate well-being. The small giant clam Tridacna maxima and the spider conch Lambis lambis are two...

An Empirical Study of the Distributed Ellipsoidal Trust Region Method for Large Batch Training

Ali Alnasser
Neural networks optimizers are dominated by first-order methods, due to their inexpensive computational cost per iteration. However, it has been shown that firstorder optimization is prone to reaching sharp minima when trained with large batch sizes. As the batch size increases, the statistical stability of the problem increases, a regime that is well suited for second-order optimization methods. In this thesis, we study a distributed ellipsoidal trust region model for neural networks. We use a...

Snapshot space-time holographic three-dimensional particle tracking velocimetry: video

Ni Chen, Congli Wang & Wolfgang Heidrich
videos in the paper of "Snapshot space-time holographic three-dimensional particle tracking velocimetry"

Reconstruction of Cell and Tissue-specific Immune-protein Interactomes Using Single-cell RNA Sequencing Data

Atheer Althobaiti
Protein molecules and their interactions via protein-protein interactions (PPIs) are at the core of cellular functions. While such global PPI networks have been useful for analyzing gene function and effects of genetic variants, they do not resolve tissue and cell-typespecific interactions. Here we leverage recent advances in single-cell RNA sequencing (scRNA-seq) to reconstruct cell-type-specific PPI networks across different tissues to enable a context-sensitive analysis of immune cells’ gene-protein pathways. Targeting B cells, T cells, and...

Optimal policies for battery operation and design via stochastic optimal control of jump diffusions

Eliza Rezvanova
To operate a production plant, one requires considerable amounts of power. With a wide range of energy sources, the price of electricity changes rapidly throughout the year, and so does the cost of satisfying the electricity demand. Battery technology allows storing energy while the electric power is lower, saving us from purchasing at higher prices. Thus, adding batteries to run plants can significantly reduce production costs. This thesis proposes a method to determine the optimal...

Design and Implementation of Adaptive Morphology Feature for a Tetrahedron Shaped Drone

Obadah Wali
In recent years, there has been an increase in the development of drone technologies. Furthermore a considerable interest in developing drones that utilizes platforms allowing for adaptive morphology has been growing steadily. In this work, we use a quadcopter to develop a drone with the feature of transforming its shape from a flat triangle to a tetrahedron. To achieve this property, two main features are considered. First, a controller for the propeller thrust force to...

Spatial dynamics of Red Sea coral reef fish assemblages: a taxonomic and ecological trait approach

Gloria Lisbet Gil Ramos
Despite the increases in the intensity and frequency of disturbances on coral reefs in the Red Sea over the past decade, patterns of variability in fish communities are still poorly understood. This study aims to contribute to a better understanding of how fish communities vary along multiple spatial scales (10-100’ of kilometers) and to provide a baseline for future comparisons, fundamental to assess responses to climate change and other disturbances. Coral reefs along the Saudi...

Low-Noise High-Precision Readout Circuits for Capacitive MEMS Accelerometer

Kuilian Yang
Over the past two decades, Micro-Electro-Mechanical System (MEMS) based accelerometers, benefiting from relatively simple structure, low-power consumption, high sensitivity, and easy integration, have been widely used in many industrial and consumer electronics applications. For the high precision accelerometers, a significant technical challenge is to design a low-noise readout circuit to guarantee the required high resolution of the entire integrated system. There are three main approaches for improvement of the noise and offset of the readout...

Studies of Novel Small Molecule and Polymer blends for Application in Organic Light-Emitting Diodes

Despoina Gkeka
Display technology has become a vital and ubiquitous part of our daily life. Undoubtedly, today’s technologically minded society is living in the era of the digital image. After high resolution and efficiency could successfully be realized, the major trends in display technology now aim towards achieving high color purity for natural looking display colors. Organic light-emitting diodes (OLEDs), as one strong contender for high performance displays and lighting, have been undergoing tremendous industrial and commercial...

High-throughput Assay for Quantifying Transgenerational Epigenetic Inheritance in C. elegans

Sarah Al-Harbi
This thesis describes my work to develop methods and assays to study transgenerational inheritance in the widely used genetic model organism Caenorhabditis elegans (C. elegans). In the first chapter, I describe a novel method that uses an exogenous histamine-selective chloride channel (HisCl1) for negative selection in transgenesis. C. elegans transgenesis is a core technique used by most laboratories and often requires distinguishing between rare animals with a single-copy transgene inserted into the genome from more...

Wireless Network Coding with Intelligent Reflecting Surfaces

Amanat Kafizov
Conventional wireless techniques are becoming inadequate for beyond fifth-generation (5G) networks due to latency and bandwidth considerations. To increase the wireless network throughput and improve wireless communication systems’ error performance, we propose physical layer network coding (PNC) in an Intelligent Reflecting Surface (IRS)-assisted environment. We consider an IRS-aided butterfly network, where we propose an algorithm for obtaining the optimal IRS phases. Also, analytic expressions for the bit error rate (BER) are derived. The numerical results...

Autoignition and reactivity studies of renewable fuels and their blends with conventional fuels

Gani Issayev
Population growth and increasing standards of living have resulted in a rapid demand for energy. Our primary energy production is still dominated by fossil fuels. This extensive usage of fossil fuels has led to global warming, environmental pollution, as well as the depletion of hydrocarbon resources. The prevailing difficult situation offers not only a challenge but also an opportunity to search for alternatives to fossil fuels. Hence, there is an urgent need to explore environmentally...

Exploring the Reactivity of Well-defined Oxide-supported Metal­Alkyl and Alkylidyne Complexes via Surface Organometallic Chemistry

Aya Saidi
Surface Organometallic Chemistry (SOMC) is an excellent approach to erase the gap between homogeneous and heterogeneous catalysis by grafting the molecular organometallic complex on various oxide surfaces, forming well-defined and single-site catalysts. This strategy allows for better characterization as well as the improvement and development of existing and new catalysts. These surface species could promote a wide range of catalytic applications (i.e., metathesis of hydrocarbons, hydrogenolysis of alkanes, and olefin polymerization reactions) depending on the...

Hydrogen Combustion versus Diesel Isobaric Combustion in the Double Compression-Expansion Engine

Rafig Babayev
This thesis aims to contribute to the research and development of a new highly efficient split-cycle engine concept – the double compression-expansion engine (DCEE) – by expanding the knowledge of combustion processes suitable for this and, potentially, other modern engines, via experimental and computational studies. In this work, first, the importance of continued improvement of internal combustion engines is demonstrated by comparing the life-cycle CO2 emissions of different modes of transport, including walking and bicycling....

Using Google Earth Engine for the Automated Mapping of Center Pivot Irrigation fields in Saudi Arabia

Areej Alwahas
Groundwater is a vital non-renewable resource that is being over exploited at an alarming rate. In Saudi Arabia, the majority of groundwater is used for agricultural activities. As such, the mapping of irrigated lands is a crucial step for managing available water resources. Even though traditional in-field mapping is effective, it is expensive, physically demanding, and spatially restricted. The use of remote sensing combined with advanced computational approaches provide a potential solution to this scale...

On The Large-Scale Deployment of Laser-Powered Drones for UAV-Enabled Communications

Mohamed Amine Lahmeri
To meet the latest requirements of the 6G standards, several techniques have been proposed in the open literature, such as millimeter waves, terahertz communication, and massive MIMO. In addition to these recent technologies, the use of unmanned aerial vehicles (UAVs) is strongly advocated for 6G networks, as the 6G standard will not be dedicated to broadband services, but will rather be oriented towards reduced geographical cellular coverage. In this context, the deployment of UAVs is...

Exploring Cholinergic Mechanisms in Hydra through Pharmacological Intervention and Behavioral Observation

Rund Tawfiq
Efforts to uncover a cholinergic neurotransmission system in Hydra have yielded conflicting results, where early studies suggested cholinergic agents affect the animal’s movement and later studies failed to reproduce these results. The identification of cholinergic mechanisms in the Cnidarian Nematostella vectensis and the presence of nicotinic Acetylcholine receptor (nAChR)-like sequences in the published Hydra genome have led us to revisit this issue. This study explores cholinergic mechanisms in Hydra through a comprehensive approach, including bioinformatics...

High-Dimensional Analysis of Regularized Convex Optimization Problems with Application to Massive MIMO Wireless Communication Systems

Ayed Alrashdi
In the past couple of decades, the amount of data available has dramatically in- creased. Thus, in modern large-scale inference problems, the dimension of the signal to be estimated is comparable or even larger than the number of available observa- tions. Yet the desired properties of the signal typically lie in some low-dimensional structure, such as sparsity, low-rankness, finite alphabet, etc. Recently, non-smooth regularized convex optimization has risen as a powerful tool for the recovery...

Functional Metal Organic Frameworks for Surface Organometallic Chemistry and Carbon Conversion

Zeynabou Thiam
Abstract: Metal-Organic Frameworks (MOFs) are a class of highly porous, hybrid, functional and crystalline extended coordination compounds. Their exceptional properties renders them ideal for a wide range of applications including gas storage and catalysis. Especially for catalysis, MOFs are receiving attention as well-defined supports for organometallic heterogeneous catalysis with noticeably the post-synthetic grafting of transition metal complexes on secondary building units (SBU) containing hydroxides moieties. The objective of this dissertation is to explore the synthesis,...

Toward Controlled Growth of Two-Dimensional Transition Metal Dichalcogenides: Chemical Vapor Deposition Approaches

Yi Wan
Recently, atomically thin two-dimensional (2D) transition metal dichalcogenides (TMDCs) materials have drawn significant attention due to their unique optical and electrical properties1, 2. This offers unique opportunities for the next-generation electronic and optoelectronic devices3. Specifically, recent innovations in the big-data-driven prediction of new 2D materials, integration of new device architectures, interfacial engineering of contacts between semiconductor/metals and semiconductor/dielectrics as well as encapsulation in hexagonal boron nitride4, 5 have further propelled the electrical mobility to be...

High Fidelity Numerical Simulations and Diagnostics of Complex Reactive Systems

Wonsik Song
To contribute to the design of next-generation high performance and low emission combustion devices, this study provides a series of high fidelity numerical simulations of turbulent premixed combustion and autoignition with different clean fuels. The first part of the thesis consists of the direct numerical simulations (DNS) of the lean hydrogen-air turbulent premixed flames at a wide range of Karlovitz number (Ka) conditions up to Ka = 1,126. Turbulence-chemistry interaction is discussed in terms of...

Registration Year

  • 2021

Resource Types

  • Dissertation
  • Dataset
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  • King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia