Physical Sciences and Mathematics Commons^™

Regioselective Catalytic Synthesis Of Potentially Bioactive 1,3,4-Selenadiazole, Mohamed Ali Mahmoud

Theses

Isoselenocyanates have a crucial role as reactants in chemical processes, facilitating the efficient synthesis of significant chemical intermediates and physiologically active chemicals. The utilization of (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides in a one-step procedure for the synthesis of the core structure of various heterocyclic compounds has been widely explored. This study focuses on the synthesis of 5-arylimino-1,3,4-selenadiazole derivatives through the reaction of isoselenocyanates with various substituted (Z)-2-oxo-N-phenylpropanehydrazonoyl chlorides. The objective is to achieve selective and accurate formation of these derivatives. The derivatives exhibit a diverse range of functional groups on both aryl rings. The synthetic procedure is conducted under ambient conditions, promoting environmental …

Correlation Between The Preparation Methods And The Physiochemical Characteristics Of Mgal₂O₄ As A Support For Ni Catalysts In Partial Oxidation Of Methane, Fatima El Alem

Theses

Due to different technical challenges associated with direct use of methane, the main component of natural gas, its conversion to higher hydrocarbons has been a subject of great industrial importance. All of the known routes for methane conversion are catalytic processes, where the performance is largely dependent on the physicochemical properties of the catalyst. The catalysts that have shown promising performance in methane reforming are based on expensive metals such as Pt, Pd, and Ru. Ni, on the other hand, is a cost-effective metal and has shown promising catalytic activity. These catalysts are usually in the form of metal nanoparticles …

Modified Titani Derived From Ti – Oxo Clusters: Synthesis, Structure, And Photocatalytic Activity, Fatmah Rashed Ali Alkindi

Theses

Titanium dioxide (TiO₂), an important semiconductor, has been used in various applications ranging from sunblock additives to self-cleaning window coatings, antibacterial agents, photovoltaics, and photocatalysis. Due to its photostability, TiO₂ is an extensively used semiconductor photocatalyst in many industries. This thesis represents the synthesis, structure, and photocatalytic activity of TiO₂ (Anatase) photocatalyst, which was prepared using hexanuclear titanium-oxo cluster precursor via temperature-controlled calcination. The optical property of the prepared photocatalyst was investigated using UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), powder X-ray diffraction (PXRD) for phase determination, scanning electron microscopy (SEM) for morphology and structural analysis, Brunauer−Emmett−Teller …

Fabrication And Characterization Of Germanium Telluride Nanowires, Shaikha Saeed Alketbi

Theses

Random access memories (RAMs) made from phase change materials (PCMs) are a promising alternative for flash memory technology currently dominating the memory market owing to its many appealing traits such as non-volatility, fast read/write performance, excellent scalability, and compatibility with complementary metal-oxide-semiconductor (CMOS) architectures. In fact, the scalability of PCMs is driving this class of materials to be the successor in the memory industry in the near future, and germanium telluride (GeTe) is one of the most viable PCMs in this context. In this study the phase change material GeTe nanowires, is fabricated using the vapor–liquid–solid (VLS) growth method. GeTe …

Preparation And Evaluation Of Crocetin-Coated Biodegradable Polymer On Top Of Magnetite Nanoparticles For Their Anticancer Effects, Sulafa Saeed Abdelhalim Ibrahim

Theses

Liver cancer is still one of the leading causes of cancer-related deaths worldwide. This is due to many reasons including lack of effective drugs, late diagnosis of this type of cancer due to the overlapping of symptoms with many other liver diseases, and lack of effective screening tests. Targeted drug delivery systems offer many promising advantages compared to conventional chemotherapy. Targeted delivery will mitigate the bad side effects of chemotherapy such as drug resistance, low therapeutic value since the drug mostly will be administered through an IV affecting healthy and cancer cells alike, and that leads us to an important …

Levels Of Testosterone Esters In Camel Hair, Aysha Khalidi Ali Alraeesi

Theses

Doping and steroid use represent a serious threat to animal health and can even lead to their untimely and painful death. However, doping is an acute problem in today's animal racing world, particularly in camel racing. Testosterone and its ten esters (benzoate, valerate, isocaproate, hexahydrobenzoate, decanoate, undecanoate, laurate, enanthate, cypionate, and caproate) are of utmost importance because when they are administered to animals it is difficult to measure them efficiently. The levels of testosterone and its esters in camels and other animals are typically determined using urine and blood tests. The aim of this study was to develop and validate …

Fabrication Of Chemically-Functionalized 3dprinted Porous Scaffolds For Biomedical Applications, Eiman Hamed Matar Atalla Alblooshi

Theses

Hard tissues, such as bone and teeth, are natural composites of collagen nanofibers that are reinforced by inorganic calcium phosphate Nano crystallites, in the form of nanocomposites. The interlocking between these components in hard tissues explains their unique characteristics. Bone is mainly classified into two major types; compact and cancellous depending on the extent of porosity. Fractures in the compact bone can be treated using bone fixation implants, such as rods, screws, and plates, or can be totally replaced by bone implants if complete substitution is required. Cancellous bone, on the other hand, is highly porous and its substitution with …

Partial Oxidation Of Methane To Synthesis Gas Over Ni/Γ-Al₂O₃ Catalysts: The Effect Of The Structure And The Pre-Treatment Of The Support On The Catalysts’ Performance, Sheikh Tijan Jobe

Theses

Abundant natural gas is a potential source of more cost-effective energy and its effective utilization can significantly reduce the dependence on petroleum oil. Disadvantages of natural gas as a direct fuel include its low energy density by volume, and high cost of transportation, which resulted in its underutilization as an alternative energy source. Therefore, the conversion of methane to more easily-handled and value-added products is becoming a promising route for natural gas utilization. Compared to steam reforming of methane to syngas, which is the most commercially applied conversion process, partial oxidation is a more cost-effective promising route. While noble metals …

Coastal Watershed Monitoring And Management: Geomorphology, Geochemistry, And Hydrologic Modeling Of Los Peñasquitos Creek, Ca, Ravleen Khalsa-Basra

Theses

Rivers in semi-arid climates are directly influenced by local geographic and hydrologic conditions and impacted by modifications to hydrology via urbanization. Changes can influence erosion, morphology, habitat sustainability, and watershed health. In highly urbanized southern California coastal regions, these rare open spaces provide vital ecosystem services. Los Peñasquitos Creek in San Diego County is one such watershed. Using stream surveying and laboratory methods we quantified channel characteristics, grain size distribution, total metal concentration [M], organic carbon (%OC), and phosphate to longitudinally characterize the creek for improved management. Results identified three distinct reaches in the watershed (upper, middle, lower). Downstream, depth …

Otolith Microchemistry Reveals Low Habitat Connectivity Of California Killifish (Fundulus Parvipinnis) Across A Range Of Spatial Scales, Lisa Robison

Theses

As wetlands face continued fragmentation worldwide, an understanding of habitat connectivity and how fishes that rely on these environments is imperative to conduct effective marine management. Site fidelity and habitat connectivity are vital measures of the interdependence of fish populations living in neighboring marshes (or in regions of a single marsh).

Here, we examine the habitat connectivity, site fidelity, and movement of California killifish (Fundulus parvipinnis) within and among three estuaries in Southern California through otolith microelemental analysis. Assessing the site fidelity of estuarine fishes is important to determine the level of connectivity between spatially distinct populations within …

Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright

Theses

Anomalously elevated arsenic concentrations occur at an abandoned artisanal mine site in an open space recreational park in urban San Diego County, California. Although mining at the site ceased 100 years ago little to no remediation efforts took place leaving shafts, adits, waste piles and derelict infrastructure accessible by inquisitive hikers and adventurers frequenting Black Mountain Open Space Park. This study evaluates the geochemical mechanisms of As transport downgradient from the mine and examines the contribution of both climate and urbanization on the restriction of As mobility. Sediment As concentrations reach 2,320 mg/kg (483 times background crustal concentrations; n=73) along …

Development Of Analytical Methods For The Determination Of Β-Lactam Antibiotic Residues In Meat, Milk And Dairy Products, Melissa Di Rocco

Theses

In this project, analytical methodologies for the determination of β-lactam antibiotic residues in meat and dairy products were developed and validated using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The methods included the main penicillins, cephalosporins and carbapenems commonly employed in human or veterinary medicine for the treatment of bacterial infections. A multi-residue method for the analysis of 30 β-lactams was developed and validated in bovine muscle using dispersive-solid phase extraction (d-SPE), reversed-phase chromatography and mass spectrometry detection. A number of sorbent materials were assessed for clean-up, and a simple and straightforward sample preparation protocol developed for …

Treated Hfo2 Based Rram Devices With Ru, Tan, Tin As Top Electrode For In-Memory Computing Hardware, Yuvraj Dineshkumar Patel

Theses

The scalability and power efficiency of the conventional CMOS technology is steadily coming to a halt due to increasing problems and challenges in fabrication technology. Many non-volatile memory devices have emerged recently to meet the scaling challenges. Memory devices such as RRAMs or ReRAM (Resistive Random-Access Memory) have proved to be a promising candidate for analog in memory computing applications related to inference and learning in artificial intelligence. A RRAM cell has a MIM (Metal insulator metal) structure that exhibits reversible resistive switching on application of positive or negative voltage. But detailed studies on the power consumption, repeatability and retention …

Estimation Of The Removal Of Chiral Pharmaceutical Drugs From Domestic Wastewater Using Uplc-Ms/Ms, Mohammed Khaled Mohammed Al Tabaji

Theses

This thesis is concerned with the estimation of the removal of chiral pharmaceutical compounds (PCs) from domestic wastewater in Al Ain using UPLC-MS/MS. PCs are classified into many classes such as hormones, antibiotics, analgesics, cosmetic products, ꞵ blockers, and anti-inflammatory drugs. PCs do not have a guideline to describe their concentrations in treated domestic wastewater. Additionally, there is a very high demand for using PCs around the world, which results in their discharge to wastewater at relatively high masses, which could be harmful to the environment. Furthermore, very limited work has been done to estimate the removal of chiral PCs. …

Mass Spectrometric Determination Of Retinol In Emirati Population, Israa Samir Mohamed Shawky El-Konaissi

Theses

This thesis is concerned with analyzing vitamin A deficiency. Vitamin A is crucial for several functions, including vision, growth, and cell differentiation. the main aim is to develop and validate an LC-MS/MS method for the determination of vitamin A in plasma matrix and use the new method for the determination of vitamin A levels in the obese Emirati population. Methods: A positive ion electrospray ionisation (ESI) LC-MS/MS method was used in the Multiple Reaction Monitoring (MRM) mode for quantification. It involved i) LC-MS/MS, ii) a guard column together with C18 Ascentis Express F5 column iii) Internal standard, 25-Hydroxyvitamin D3 (6, …

Mass Spectrometric Determination Of Retinol In Emirati Population, Israa Samir Mohamed Shawky El-Konaissi

Theses

This thesis is concerned with analyzing vitamin A deficiency. Vitamin A is crucial for several functions, including vision, growth, and cell differentiation. the main aim is to develop and validate an LC-MS/MS method for the determination of vitamin A in plasma matrix and use the new method for the determination of vitamin A levels in the obese Emirati population. Methods: A positive ion electrospray ionisation (ESI) LC-MS/MS method was used in the Multiple Reaction Monitoring (MRM) mode for quantification. It involved i) LC-MS/MS, ii) a guard column together with C18 Ascentis Express F5 column iii) Internal standard, 25-Hydroxyvitamin D3 (6, …

Determination Of Vitamin D Metabolites And Their Epimers In Obese Emirati Population, Bashar Hiatham Alzohily

Theses

Vitamin D deficiency is a global issue, and despite all-year-round sunshine, it is a big problem in the UAE. Obesity or overweight refers to an accumulation of excessive fat that may harm health so, it is considered a worldwide health concern. The accurate measurement of vitamin D active forms is a problematic issue. This study aimed to develop and validate a UHPLC-MS/MS method for the new method for determining vitamin D levels in the obese Emirati population. The vitamin D epimers and other metabolites were determined by UHPLC-MS/MS system, model 8060. The methods include the collection of blood samples from …

Determination Of Vitamin D Metabolites And Their Epimers In Obese Emirati Population, Bashar Hiatham Alzohily

Theses

Vitamin D deficiency is a global issue, and despite all-year-round sunshine, it is a big problem in the UAE. Obesity or overweight refers to an accumulation of excessive fat that may harm health; so, it is considered a worldwide health concern. The accurate measurement of vitamin D active forms is a problematic issue. The aim of this study was to develop and validate a UHPLC-MS/MS method for the determination of vitamin D metabolites and their epimers and then apply the new method for the determination of vitamin D levels in the obese Emirati population. The vitamin D epimers and other …

Development Of Supramolecular Multicomponent Chromophores Towards Photoluminescence Switches, Rukayat Shola Bojesomo

Theses

A new fluorescent dye (4PBZC) comprises of coumarin (C), piperazine (P), and benzimidazole (BZ) was designed, prepared, and complexed to cucurbit[7]uril (CB7) to detect carnosol (CAR), an anti-breast cancer drug, in sub-nanomolar concentrations utilizing the supramolecular indicator displacement assay (IDA) strategy, the CB7-assisted pKa shift and the CB7-retarded photoinduced electron transfer (PET) process. The host−guest complexation was confirmed by UV−visible absorption, fluorescence, and proton NMR spectroscopy, which confirm binding to 4PBZC via the BZ moiety. Also, CB7 preferentially binds the indicator dye via the protonated BZ residue compared to the neutral BZ one, demonstrated by a higher binding …

Synthesis, Characterization, Electronic Structure Of Biocl/Biobr/Rgo Ternary Heterojunction And Its Photocatalytic Activities, Salama Yousef Alismaail

Theses

Solar energy is free, most abundant among all renewable energy sources. Energy from the sun reaches the earth surface at a rate of 1.2 X 10⁵ TW by far, exceeding the current world energy consumption of 17 TW (1TW = 10¹² J/s). Accordingly, development of visible light driven photocatalysts is of considerable interest in clean and renewable energy, as well as in wastewater treatment.

In that context, BiOCl and BiOBr and three different mole ratio composites were prepared, characterized using UV-vis DRS, PXRD, BET, SEM, and EDX and their photocatalytic activity for the photoreduction of 4-NA was evaluated. …

One-Pot O-Alkylation And C-C Cross-Coupling Reactions Involving Stabilized Phosphoranes, Areej Hashim Elamin Mohamed Ali

Theses

This thesis is concerned with the one-pot reactions that are considered to be beneficial to preserve resources, save time, and are deemed a green chemistry strategy. To plan such one-pot reactions, it is important to combine two or more reactions that are compatible with each other and can be run under the same reaction conditions. In this work, possibilities of a combination of Wittig-olefination and Suzuki C-C-cross coupling reactions are explored further. Reaction sequences involve the combination of a Suzuki-reaction / Wittig olefination, a Suzuki reaction / Wittig olefination/hydrolysis, and a Suzuki-reaction / double Wittig olefination. In all cases, stabilized …

Mass Spectrometric Determination Of Retinol In Emirati Population, Israa Samir Mohamed Shawky El-Konaissi

Theses

This thesis is concerned with analysing vitamin A deficiency. Vitamin A is crucial for several functions, including vision, growth, and cell differentiation. the main aim is to develop and validate an LC-MS/MS method for the determination of vitamin A in plasma matrix and use the new method for the determination of vitamin A levels in the obese Emirati population. Methods: A positive ion electrospray ionisation (ESI) LC-MS/MS method was used in the Multiple Reaction Monitoring (MRM) mode for quantification. It involved i) LC-MS/MS, ii) a guard column together with C18 Ascentis Express F5 column iii) Internal standard, 25-Hydroxyvitamin D3 (6, …

Fabrication, Characterization And Applications Of Chemically Modified Planar Metallic Electrodes From Copper Clad Sheets, Rana T. K. Alsaidi

Theses

In this work, we developed a fabricating method for planar electrodes by milling and cutting copper-clad sheets. The main objectives of this thesis are to produce customized planar electrodes with different geometries with relatively higher reusability compared to the screen-printed electrodes available by commercial vendors. The fabricated electrodes from copper-clad sheets were electroplated with different metals using commercial electroplating baths to produce different metallic planar electrodes. Also, the fabrication of planar electrodes with cavities to be filled with modified carbon paste was done. The electroplated planar electrodes were characterized by the cyclic voltammetry technique. In addition to that, they were …

Development Of Novel Peroxidase-Tio2/Zno Hybrid Catalysts For The Degradation Of Emerging Pollutants, Rana Fawzi Mohamed Mohamed Morsi

Theses

Water pollution by different organic compounds is one of the most important environmental issues that is attracting the attention of many scientists due to its direct potential bad effect on human health. These organic pollutants include pesticides, pharmaceuticals, industrial wastes, and personal care products that are released in water bodies from domestic and industrial discharge. Various chemical, physical and biological approaches have been proposed to degrade these contaminants from the polluted water. In the present study, we immobilized versatile thermostable enzymes, Soybean peroxidase (SBP) and Horseradish peroxidase on functionalized photocatalysts - TiO2 and ZnO to create novel bio-composite catalysts (SBP-TiO2, …

Evaluation Of A New Approach For Qualitative Gas Analysis Based On Diffusion Properties, Abdalla Jamal Muhammad Abunamous

Theses

The design and construction of a 6-channel parallel gas diffusion system and its application to evaluating the proposed novel approach for gas fingerprinting are described. The present gas diffusion system allows the simultaneous recording of the pressure accumulation of the permeating test gas behind six different gas permeable membranes, respectively. The obtained simultaneous diffusion rates through different membranes demonstrated clear potential as a new technique for qualitative gas identification of the ten test gases used in the present work. The test gases were helium, neon, argon hydrogen, nitrogen, carbon dioxide, methane, ethane, propane, and ethylene, which are representative examples of …

Synthesis And Biological Applications Of Some Novel Urea And Thiourea-Benzimidazole Derivatives, Lamia Ali Siddig Ali

Theses

The objective of this research is the synthesis and characterization of novel urea and thiourea-benzimidazole derivatives and to test their biological activities. The 17 novel compounds (57a-j), (58a-d), 62, 63, and 65 have been synthesized, purified by different techniques such as extraction and column chromatography, and then characterized by using suitable spectroscopic techniques including ^¹H-NMR, ¹³C-NMR, fluorescence, and IR spectroscopy techniques.

The biological activity of these compounds has been studied. The antibacterial activity was evaluated at different concentrations (μg/ ml) against 6 types of bacteria (Esherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Klebsiella pneumoniae, Staphylococcus aureus …

Synthesis And Biological Applications Of Some Novel Urea And Thiourea-Quinoline Derivatives, Aysha Mohammed Subaih Jaarouf Alkaabi

Theses

Extensive literature survey reveals that 8-Hydroxyquinoline (8-HQ), urea, thiourea and piperazine exhibit wide biological activity profile such as anticancer, anti-Alzheimer, anti-viral, antibacterial and antifungal activity. Novel urea and thiourea-quinoline derivatives connected by piperazine moiety have been synthesized and purified using appropriate techniques (extraction, crystallization and column chromatography) followed by characterization using IR spectroscopy and NMR spectroscopy (both ³H and ¹³C).

Biological activity, metal chelation properties and the photo-physical properties were studied for these novel compounds. Anti-bacterial study shows moderate activity for most of the compounds against P.aereginosa, S.aureus and Enterococcus at concentration 250 μM. Antifungal study showed high potency …

Preparation And Characterization Of Novel Azocinnamates And Steroidal Azo Ethers, Abdullah Maamon Alhemyari

Theses

This thesis is concerned with the synthesis of novel azo-cinnamates and of steroidal azo ethers and with the analysis of the spectroscopic and thermal properties of these materials. The compounds were identified as possible photoswitchable liquid crystals. The molecules were prepared by multi-step sequences, involving etherification, azo coupling, and Appel-type reactions as the key steps in the case of the azo-cinnamates, and Finkelstejn reactions and Williamson-type etherification reactions as the major transformations in the case of the steroidal azo ethers. The preparation of the azo-cinnamates was a further example of an esterification reaction run under Appel-type conditions using BrCCl₃/PPh₃. The …

Assessing The Recyclability Of Stainless-Steel Powder Used In Selective Laser Melting-3d Printing, Alexis I. Keaton

Theses

Additive manufacturing (AM) is becoming one of the most distinctively growing versatile technologies. In most AM techniques that requires the use of powder, the powder that is not fused into the 3D print can be replenished and used for another build. Unfused powder is generally collected on the powder-bed after an AM build is complete. In most cases, the ability to replenish unfused powder with virgin powder aids in limiting any significant change in powder’s properties that may cause compromising the quality of the 3D prints. If no powder is added to the recycled powder it is likely to shift …

Attempted Synthesis Of 4’-Hydroxyacetophenone-1h-Benzotriazole By Benzyne-Azide Click Chemistry, Kevin Kee-Hoe Cheah

Theses

Ultraviolet light absorber or stabilizer (UVLS) is one of the many additives that is incorporated into a polymer formulation which functions by preferentially absorbing the UV light to prevent its photodegradation. UVLS such as 2-hydroxyphenylbenzotriazole (2H-BZT) and its derivatives are commercially used UV-light absorbers in different polymers. The synthesis of 2H-benzotriazoles solely relies on the two-step azo-coupling of the diazonium salt and reductive cyclization where the former reaction suffers from poor yield.1 The presence of a phenolic hydrogen in the ortho position to the phenyl ring attached to the nitrogen atom on the benzotriazole imparts excellent photochemical stability to the …