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Effects Of Thai Silk Fibroin Content On Properties Of Bioactive Glass-Silk Fibroin Hybrid Scaffolds, Ayuth Vejpongsa

Chulalongkorn University Theses and Dissertations (Chula ETD)

Hybrid scaffolds of bioactive glass (BG) and silk fibroin (SF) were fabricated. 70S30C (70% mol Si, 30% mol Ca) BG is a ceramic biomaterial with natural bone bonding and osteoconductivity potentials. SF is a natural polymer from the silk cocoon of bombyx mori with many desirable properties for tissue engineering applications. Hybridisation between these two biomaterials could mitigate the brittle characteristic of ceramic, enabling the scaffold to resist cyclic load better. This study varied the ratio between BG and SF (BG:SF; 100:0, 95:5, 90:10, 85:15, 80:20, 0:100) and characterized the scaffolds, noting the difference between the scaffolds as a result …

Guerbet Reaction Of Ethanol To Butanol Over Mgai Mixed Oxide Catalysts, Patchaporn Seekhiaw

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to investigate the Guerbet reaction of ethanol to butanol over MgAl mixed oxide catalysts. The MgAlO catalyst was obtained from calcination of MgAl-LDH. This study has been divided into three sections. In the first section, the effect of ethanol flow rate and nitrogen flow rate on Guerbet reaction of ethanol to butanol were examined. It was found that the optimal condition of ethanol flow rate and nitrogen flow rate for Guerbet reaction were at the weight hour space velocity (WHSV) of 3.1 h-1 and 900 mL/h of nitrogen flow rate, which gave 3.94% of butanol yield. Therefore, …

Improving Feature Learning Capability And Interpretability Of Unsupervised Neural Networks, Chathurika S. Wickramasinghe Brahmana

Theses and Dissertations

The motivation for this dissertation is two-prong. Firstly, the current state of machine learning imposes the need for unsupervised Machine Learning (ML). Secondly, once such models are developed, a deeper understanding of ML models is necessary for humans to adapt and use such models.

Real-world systems generate massive amounts of unlabeled data at rapid speed, limiting the usability of state-of-the-art supervised machine learning approaches. Further, the manual labeling process is expensive, time-consuming, and requires the expertise of the data. Therefore, the existing supervised learning algorithms are unable to take advantage of the abundance of real-world unlabeled data. Thus, relying on …

Modeling Of Patient-Specific Periaortic Mechanics And Pulmonary Artery Hemodynamics Based On Phase-Contrast Magnetic Resonance Imaging Sequences., Johane H. Bracamonte

Theses and Dissertations

Inverse modeling in cardiovascular medicine is a collection of methodologies that can provide non-invasive patient-specific estimations of clinical risk factors using medical imaging as inputs. Its incorporation into clinical practice has the potential to improve diagnosis and treatment planning with low associated risks and costs.

Herein, three different phase contrast magnetic resonance imaging (MRI) modalities were implemented as input data, displacement encoding with stimulated echoes (DENSE MRI) applied, and time-resolved velocity encoding phase-contrast MRI, in 1D and 3D, applied to pulmonary artery (PA) hemodynamics.

A model to account for the effect of periaortic interactions due to static and dynamic structures …

Towards The Systematic Evaluation Of Variable Modes Of Mechanical Conditioning On The Compositional, Microstructural And Mechanical Properties Of Engineered Tissue Vascular Grafts., Sarah Saunders

Theses and Dissertations

Coronary artery bypass surgery (CABG) remains one of the most common cardiac surgical procedures performed worldwide, frequently involving multiple bypasses, and commonly employing the patient’s internal mammary artery, radial artery, or saphenous vein. CABG is often not possible because native vessels were already employed in previous interventions or are diseased themselves. Synthetic vascular grafts are currently integral tools of vascular surgery and have had relative success in large-caliber applications providing substantial benefit to aortic or iliac grafting; however, small diameter (< 6 mm) arterial grafts have not yet translated into clinical effectiveness due to thrombosis and anastomotic intimal hyperplasia. ETVGs present an exciting potential alternative in vascular grafting by offering a blood vessel substitute that could exhibit all the functional characteristics of native vasculature. In addition to relieving supply limitations associated with coronary artery bypass surgery ETVGs are especially ideal for pediatric patients with congenital heart disease who require grafts that grow as they do, eliminating the need for reoccurring invasive surgeries.

Though the role of biomechanics in regulating cellular behavior promoting non-thrombogenicity, vasoactivity, and ECM synthesis and maintenance is well …

Branched Chain Amino Acid Strain State Monitoring With Raman Spectroscopy And Plasmonic Bowtie Nanoantenna Devices For Early Disease Detection, Caroline A. Campbell

Theses and Dissertations

This work centers on the development and the down-selection of nano-manufactured devices to be used in conjunction with Raman spectroscopy for probing a branched chain amino acid. The nano-manufactured devices integrate plasmonic nanoantennas for the purpose of amplifying molecular fingerprints, which are otherwise difficult to detect, through Surface Enhanced Raman Spectroscopy (SERS). Plasmonic nanostructures can be utilized for a variety of biomedical and biochemical applications to detect the characteristic fingerprint provided by Raman Spectroscopy. The nano-manufactured devices create an electric field that amplifies minute perturbations and raises the signal above background noise. This may provide a deeper understanding of signal …

Effect Of Viscoelasticity On Cellular Morphology And Activity, Thomas J. Petet Jr

Theses and Dissertations

It has been well established that there is a link between substrate stiffness and cellular activities such as proliferation, migration, and differentiation. Less characterized is the link between the time-dependent viscosity of a substrate with those cellular activities. To explore this, PDMS substrates were created with predictably tunable stiffness and viscosity parameters. A simulated model was also developed in parallel to explore the potential effects of viscosity in a computationally predictive way. It was found that the inclusion of viscosity caused a major paradigm shift to a non-zero substrate equilibrium that was sensitive to increases in the substrate stiffness. Finally, …

Smart City Management Using Machine Learning Techniques, Mostafa Zaman

Theses and Dissertations

In response to the growing urban population, "smart cities" are designed to improve people's quality of life by implementing cutting-edge technologies. The concept of a "smart city" refers to an effort to enhance a city's residents' economic and environmental well-being via implementing a centralized management system. With the use of sensors and actuators, smart cities can collect massive amounts of data, which can improve people's quality of life and design cities' services. Although smart cities contain vast amounts of data, only a percentage is used due to the noise and variety of the data sources. Information and communication technology (ICT) …

Bio-Composite Of Nipa Palm Husk Derived Activated Carbon/Poly(Butylene Succinate): An Effective Agricultural Waste Based Adsorbent For Ammonia Removal, Chaichana Piyamawadee, Viboon Sricharoenchaikul, Duangdao Aht-Ong

Journal of Metals, Materials and Minerals

In this work, activated materials were successfully prepared by pyrolyzing various ratios of Nipa palm husk powder to potassium hydroxide  (1:1, 1:2, and 1:3) at predetermined temperatures (500℃, 600℃, and 700℃). The surface area was obtained from nitrogen isotherms using the Brunauer-Emmett-Teller (BET) equation. The surface area of the prepared activated carbon was increased with decreasing potassium hydroxide impregnation ratio and increasing pyrolyzing temperature. The highest surface area was 1,211 m2×g-1. In contrast, acidic surface functional groups investigated by Boehm’s titration were increased with decreasing pyrolyzing temperature and impregnation ratio. Ammonia removal capacity was increased with an increase in the …

Synthesis And Phosphate Adsorption Performance Of Elephant Dung Biochar Modified With Magnesium And Iron, Navod Abeysinghe, Kaewta Jetsrisuparb, K.H.T. Karunarathna, E.P.S. Chandana, Siraprapa Suwanree, Pornnapa Kasemsiri, Prinya Chindaprasirt, Jesper T.N. Knijnenburg

Journal of Metals, Materials and Minerals

The large production volume combined with the high lignocellulose content makes elephant dung an attractive and underutilized biomass resource, but also presents waste management problems for elephant orphanages. This study explored the conversion of elephant dung into biochars by slow pyrolysis at 500°C for the recovery of phosphate. The unmodified biochar (BC500) had a specific surface area (SBET) of 62.5 m2×g-1 with point of zero charge (pHPZC) of 7.7. Biochar modification with MgCl2 (MgBC500) and FeCl3 (FeBC500) by pre-pyrolysis treatment affected the SBET (48.7 m2×g-1 and 259.4 m2×g-1, respectively) and pHPZC (8.7 and 3.3, respectively). In FeBC500, Fe was present …

Utilization Of Freeze Thaw Process For Polyvinyl Alcohol/Sodium Alginate (Pva/Sa) Hydrogel Composite, Rapeepan Muangsri, Piyachat Chuysinuan, Thanyaluck Thanyacharoen, Supanna Techasakul, Pongpat Sukhavattanakul, Sarute Ummartyotin

Journal of Metals, Materials and Minerals

Polyvinyl alcohol/sodium alginate (PVA/SA) hydrogel was successfully prepared by freeze thaw process. Without crosslinking agent, hydrogel was formed by using 3, 5 and 7 consecutive cycles of freeze thaw. Hydrogel can be formed by hydrogen bonding formation between OH-group of sodium alginate and polyvinyl alcohol throughout network. Scanning electron microscope reported that microstructure of hydrogel was well packed. The interconnect porosity was also observed. Differential scanning calorimetry exhibited that two exothermic peaks at temperature of 110℃ and 225℃ were observed due to evaporation of water molecule and melting temperature of hydrogel, respectively. The swelling behavior was rapidly increased within initial …

A Molecular Dynamics Simulation Study To Investigate The Effect Of C60 On Thermo- Mechanical And Elastic Properties Of Dgeba/Deta Nanocomposites, Dhritiman Talukdar, Sudipta Halder, Subhankar Das, M.S. Goyat, Abhishek Kumar Mishra

Journal of Metals, Materials and Minerals

Molecular dynamics simulations were performed to investigate the effect of  fullerenes (C60) on the thermal and mechanical properties of a cross-linked epoxy system composed of epoxy resin DGEBA and curing agent DETA. Hence, a comparative investigation was performed on the thermal and mechanical properties of DGEBA/DETA reinforced with 2.3 wt% C60 and neat epoxy systems. Properties such as glass transition temperature (GTT), coefficients of thermal expansion (CTE), and elastic properties at different cross-linking densities. Simulation results indicated that the GTT of the epoxy increased by about 25 K due to the presence of C60. The effect of C60 on the …

Multi-Responsive Rotaxane With Tunable Fluorescence Under Azobenzene-Based Benzoxazine Structure, Sorapat Niyomsin, Suwabun Chirachanchai, Toshikazu Takata

Journal of Metals, Materials and Minerals

Rotaxanes are known for the mechanically interlocked molecules for decades. The present work demonstrates a method to prepare multi-responsive rotaxane by conjugating with a multi-responsive supramolecule. Benzoxazine dimers, N, N’-bis(3,5-dimethyl-2-hydroxybenzyl) methylamine derivatives, are good models because their simple chemistry. An azobenzene containing benzoxazine with remaining hydroxyl group for further conjugation with rotaxane was designed. The ring opening of rotaxane using fluorescent phenol provides benzoxazine dimer with metal ion responsive and fluorescent properties. Based on this concept, light responsive benzoxazine conjugated with rotaxane system shows light, metal ion and rotaxane shuttling responsiveness which can be followed by fluorescent signals. The present …

Preparation Of Bacterial Cellulose Film From Rotten Fruits For Mulching Film Application, Nattapong Pinpru, Varol Intasanta, Thitirat Charoonsuk, Supharada Khaisaat, Oubonwan Sawanakarn, Naratip Vittayakorn, Somsak Woramongkolchai

Journal of Metals, Materials and Minerals

This research aims to reduce production capital costs and added value to natural products. The bio-mulching film was prepared by bacterial cellulose (BC) “Acetobacter xylinum”, extracted from three rotten fruits, grape, coconut, and pineapple under standard tests in the laboratory. The analysis from the FTIR technique confirmed to cellulose molecular vibration of BC films. XRD pattern was matched to structure crystallinity of JCPDS standard file which possessed a high percentage of crystallinity. The SEM micrographs were also revealed the 3D nanofiber network structure. The absorption capability of BC films could highly hold water in its structure. In addition, …

Effect Of Pore Modifiers On Physical And Mechanical Properties Of High-Performance Cement Mortar, Kisun Chunti, Sureerat Polsilapa, Parinya Chakartnarodome, Passakorn Sonprasarn, Wichit Prakaypan, Edward A. Laitila

Journal of Metals, Materials and Minerals

Two different pore modifiers (PM), artificial pozzolan (AP) and modified aluminum salt (MA), were introduced into the composition of a High Performance Cement Mortar (HPCM). The chemical compositions of raw materials, ordinary Portland cement (OPC), sea sand, AP, and MA were identified by X-Ray Fluorescence spectrometry (XRF). The hydration kinetics resulting from each PM added to the HPCM was investigated by the relevance of hydration temperature. The mechanical properties such as compressive strength, dynamic modulus of rupture, and dynamic modulus of elasticity were measured as well as water absorption and density. Additionally, Scanning Electron Microscope (SEM) and Brunauer-Emmett-Teller (BET) were …

Green Acidic Catalyst From Cellulose Extracted From Sugarcane Bagasse Through Pretreatment By Electron Beam Irradiation And Subsequent Sulfonation For Sugar Production, Thitirat Rattanawongwiboon, Prim Chanklinhorm, Threeraphat Chutimasakul, Tanagorn Kwamman, Wilasinee Kingkam, Rattapon Khamlue, Sarute Ummartyotin

Journal of Metals, Materials and Minerals

The objective of this research is to prepare a green acidic catalyst from cellulose derived from sugarcane bagasse (SB). Initially, SB was pretreated by electron beam irradiation with a dose of 50 kGy to 200 kGy and subsequent acid hydrolysis to obtain cellulose. The cellulose derived from SB was carbonized at different temperatures for 4 h and then sulfonated with heating at 120°C under reflux. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to confirm the successful preparation of acidic catalyst by irradiation pretreatment and subsequent sulfonation. The cellulose derived from irradiated SB at the lowest dose …

Artificial Intelligence (Ai): The New Look Of Customer Service In A Cybersecurity World, Sharon L. Burton

Publications

Cybersecurity leaders are not adequately developed to guide the re-engineering of quality customer service (QCS) workflows, designed with automation and AI, that interrelate with people through customers’ perceptions. Realizing re-engineering processes should be a team effort with well-versed leadership and stakeholders guiding the successful design through a follow-up process. Leaders must shape compelling and straightforward needs to learn and teach employees and chat boxes indispensable customer service skills demonstrating patience, self-discipline, flexibility, and resourcefulness in communication with irritated customers or difficult circumstances. Whether the analysis, design, development, and implementation struggles are vacuums in cybersecurity knowledge, skill, and abilities or a …

Visual Oscillation Effects On Dynamic Balance Control In People With Multiple Sclerosis, Lara I. Riem, Scott A. Beardsley, Ahmed Z. Obeidat, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Background: People with multiple sclerosis (PwMS) have balance deficits while ambulating through environments that contain moving objects or visual manipulations to perceived self-motion. However, their ability to parse object from self-movement has not been explored. The purpose of this research was to examine the effect of medial-lateral oscillations of the visual field and of objects within the scene on gait in PwMS and healthy age-matched controls using virtual reality (VR).

Methods: Fourteen PwMS (mean age 49 ± 11 years) and eleven healthy controls (mean age: 53 ± 12 years) participated in this study. Dynamic balance control was assessed while participants …

Kg-Cnn: Augmenting Convolutional Neural Networks With Knowledge Graphs For Multi-Class Image Classification, Aidan O'Neill

Dissertations

Computer vision is slowly becoming more and more prevalent in daily life. Tesla has recently announced that it plans to scale up the manufacturing of their Robotaxis by 2024, with this increase in self-driving vehicles being just one example, the importance of computer vision is growing year by year. Vision can be easy to take for granted, as most humans grow up using vision as their primary way of absorbing environmental information. The way humans process and classify visual information differs significantly from how current computer vision systems process and organise visual information. The human brain can use its past …

The Lognometer: A New Normalized And Computerized Device For Assessing The Neurodevelopment Of Fine Motor Control In Children, Christian O'Reilly, Rejean Plamondon, Nadir Faci

Publications

Motor skills are fundamental for the development of children. Neurodevelopmental tests currently used by professionals for measuring motor control maturity exhibit several limitations. To address some of these, we have designed the Lognometer, a tablet-based device that can run computerized neuromotor tests. To normalize this tool against a representative population, we collected handwritten triangles from 780 children. We used the Sigma-Lognormal model and a prototype-based parameter estimation algorithm to analyze these movements. To ensure clinical acceptance, we developed an explainable solution relying on statistical regression. We evaluated how well the proposed lognormal decomposition captures the motor control maturation between 6 …

Comparing Symbolic And Connectionist Algorithms For Correlating The Age Of Healthy Children With Sigma-Lognormal Neuromuscular Parameters, Zigeng Zhang, Christian O'Reilly, Rejean Plamondon

Publications

It is important to accurately evaluate the motor control maturity to help physicians diagnose delayed or abnormal motor development in children. Traditionally, it has been challenging to design assessment methods that are practical and accurate at the same time. This study aims to develop an effective algorithm to predict motor control maturity based on the Kinematic Theory of rapid human movements. We used handwritten pen strokes made on an electronic tablet by 513 children (5.5 to 13 years of age). We considered two types of movements: a single stroke and a triangle drawing test. For the analysis, Sigma-Lognormal parameters were …

Evaluation Of Novel Preformed Particle Gels For Conformance Control And Acid Stimulation Through Core Flooding Tests, Shuda Zhao

Doctoral Dissertations

"Acid stimulation and conformance control are two major methods to improve oil production. This study systematically evaluates two newly developed gels: Degradable Preformed Particle Gel (DPPG) and Re-crosslinkable Preformed Polymer Gel (RPPG). DPPG is designed to be a temporary plugging agent for acid stimulation and can self-degrade into a water-like fluid. RPPG is designed for reservoir sweep efficiency improvement and can re-crosslink to each other and form an immobile bulk gel after being placed in fractures or fracture-like conduits.

For DPPG, this study evaluates the effect of monomer, crosslinker, and initiator concentration on the swelling and degradation performance. Results show …

The Aquatic Particle Number Quandry, Alexander B. Bochdansky, Huanqing Huang, Maureen H. Conte

OES Faculty Publications

Optical surveys of aquatic particles and their particle size spectra have become important tools in studies of light propagation in water, classification of water masses, and the dynamics of trophic interactions affecting particle aggregation and flux. Here, we demonstrate that typical settings used in image analysis vastly underestimate particle numbers due to the particle – gel continuum. Applying a wide range of threshold values to change the sensitivity of our detection system, we show that macrogels cannot be separated from more dense particles, and that a true particle number per volume cannot be ascertained; only relative numbers in relation to …

Impact Of Orthophosphate As A Corrosion Inhibitor And Chloramine Disinfectant On Drinking Water Biofilm Communities, Mitchell Cooke

Theses and Dissertations (Comprehensive)

A drinking water distribution system (DWDS) must maintain conditions within quality standards which assure the effective and safe transport of finished drinking water from treatment plants to the household tap. Although safe to drink, finished water is not sterile, and may contain hundreds of microorganisms in a single milliliter. These microorganisms are present from the source waters, such as lakes, rivers and aquifers, and have passed through early treatment steps. Final treatment steps, such as the maintenance of disinfectant residuals, are used to further minimize viable cells present and focus on the reduction of harmful organisms. Microbial cells entering the …

In-Flow Dynamics Of An Area-Difference-Energy Spring-Particle Red Blood Cell Model On Non-Uniform Grids, Brendan Walsh, Fergal Boyle

Articles

In this paper the area-difference-energy spring-particle (ADE-SP) red blood cell (RBC) structural model developed by Chen and Boyle is coupled with a lattice Boltzmann flux solver to simulate RBC dynamics. The novel ADE-SP model accounts for bending resistance due to the membrane area difference of RBCs while the lattice Boltzmann flux solver offers reduced computational runtimes through GPU parallelisation and enabling the employment of non-uniform meshes. This coupled model is used to simulate RBC dynamics and predictions are compared with existing experimental measurements. The simulations successfully predict tumbling, tank-treading, swinging and intermittent behaviour of an RBC in shear flow, and …

Formation Of Gold Nanoparticle Self-Assembling Films In Various Polymer Matrices For Sers Substrates, Ksenia A. Maleeva, Ilia E. Kaliya, Anton P. Tkach, Anton A. Babaev, Michail Baranov, Kevin Berwick, Tatiana S. Perova, Alexander V. Baranov, Kirill V. Bogdanov

Articles

Surface-enhanced Raman spectroscopy (SERS) is regarded as a versatile tool for studying the composition and structure of matter. This work has studied the preparation of a SERS substrate based on a self-assembling plasmonic nanoparticle film (SPF) in a polymer matrix. Several synthesis parameters for the SPF are investigated, including the size of the particles making up the film and the concentration and type of the self-assembling agent. The result of testing systems with different characteristics is discussed using a model substance (pseudo isocyaniniodide). These models can be useful in the study of biology and chemistry. Research results contain the optimal …

Life-Cycle Assessment Of Non-Domestic Building Stocks: A Meta-Analysis Of Current Modelling Methods, Julian Bischoff, Aidan Duffy

Articles

Building stock models (BSMs) are essential for simulating the contributions of regional and national building sectors to climate change under different policy scenarios, and for identifying pathways to climate change mitigation. To date, BSMs have focused on the operational life-cycle impacts of domestic dwellings; there has been less emphasis either on non-domestic buildings (NDBs) or full life-cycle analysis. This paper provides a first review of the theory and practice of NDB stock modelling which considers life-cycle energy, emissions and costs. A meta-analysis of the literature was undertaken involving a structured search of relevant articles in key scientific repositories. 98 in-scope …

3d-Printed Gelatin-Alginate Hydrogel Dressings For Burn Wound Healing: A Comprehensive Study, Fateme Fayyazbakhsh, Michael J. Khayat, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Burn Wound Treatment is Still a Clinical Challenge Due to the Severity of Tissue Damage and Dehydration. among Various Wound Dressings, Hydrogel Materials Have Gained Significant Attention for Burn Wound Treatment in Clinical Practice Due to their Soothing and Moisturizing Activity. in This Study, 3D-Printed Dressings Were Fabricated using Clinically Relevant Hydrogels for Deep Partial-Thickness Burn (PTB) Wounds. Different Ratios of Gelatin and Alginate Mixture Were 3D-Printed and Examined in Terms of Rheological Behavior, Shear Thinning Behavior, Mechanical Properties, Degradation Rate, and Hydration Activity to Tune the Hydrogel Composition for Best Functionality. the Cell-Laden Dressings Were Bioprinted to Evaluate the …

Multimodal Ultrasound Imaging For Improved Metastatic Lymph Node Detection, Sidhartha Jandhyala

Dartmouth College Ph.D Dissertations

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide and is complex in nature due to the variety of organs located in the head and neck region. Knowing the metastatic state of the lymph nodes is paramount in accurately staging and treating HNSCC patients. Currently, metastatic lymph node detection involves the use of magnetic resonance imaging and/or x-ray computed tomography, followed by biopsies for histological confirmation. The main diagnostic criteria is the size of the nodes; however, current imaging methods are not 100% accurate due natural lymph node variability. Ultrasound imaging is able to provide …

Advancing Combined Radiological And Optical Scanning For Breast-Conserving Surgery Margin Guidance, Samuel Stewart Streeter

Dartmouth College Ph.D Dissertations

Breast cancer is one of the most common types of cancer worldwide, and standard-of-care for early-stage disease typically involves a lumpectomy or breast-conserving surgery (BCS). BCS involves the local resection of cancerous tissue, while sparring as much healthy tissue as possible. State-of-the-art methods for intraoperatively evaluating BCS margins are limited. Approximately 20% of BCS cases result in a tissue resection with cancer at or near the resection surface (i.e., a positive margin). A two-fold increase in ipsilateral breast cancer recurrence is associated with the presence of one or more positive margins. Consequently, positive margins often necessitate costly re-excision procedures to …