Biomedical Engineering and Bioengineering Commons^™

Dynamic Behavior And Interactions Of Ferrofluid Droplets Under Magnetic Fields In Low Reynolds Number Flows, Md Rifat Hassan

Doctoral Dissertations

Digital microfluidics in combination with emulsion microfluidics are crucial building blocks of droplet-based microfluidics, which are prevalent in a wide variety of industrial and biomedical applications, including polymer processing, food production, drug delivery, inkjet printing, and cell-based assays. Therefore, understanding the dynamics and interactions of droplets as well as the interactions between the droplets and solid surfaces are of great importance in order to improve the performance or product in these applications.

Recently, several studies in the literature have demonstrated the potential of magnetic fields in controlling the behavior of droplets in microscale; however, the fundamental mechanism behind the interesting …

Imaging Potential In Saturation Recovery Methods For Sarcoidosis Patients With Medical Devices, Samantha Zhao

Theses and Dissertations

Cardiovascular magnetic resonance (CMR) imaging is a preferred imaging methodology due to its lack of ionizing radiation and ability to detect myocardial inflammation and fibrosis using quantitative T1 mapping techniques. Cardiac sarcoidosis (CS) is characterized as the formation of granulomas in the myocardium. Current methods for detection include measuring non-cardiac specific C-reactive protein (CRP) levels, or PET imaging, which uses ionizing radiation, therefore CMR would make an ideal imaging option. However, many CS patients have implanted cardiac devices which can cause degradation in image. The modified Look-Locker inversion recovery (MOLLI) method is widely used in quantitative T1 mapping with high …

Estimating Affective States In Virtual Reality Environments Using The Electroencephalogram, Meghan R. Kumar

Theses and Dissertations

Recent interest in high-performance virtual reality (VR) headsets has motivated research efforts to increase the user's sense of immersion via feedback of physiological measures. This work presents the use of electroencephalographic (EEG) measurements during observation of immersive VR videos to estimate the user's affective state. The EEG of 30 participants were recorded as each passively viewed a series of one minute immersive VR video clips and subjectively rated their level of valence, arousal, dominance, and liking. Correlates between EEG spectral bands and the subjective ratings were analyzed to identify statistically significant frequencies and electrode locations across participants. Model feasibility and …

Effect Of Stimulus Waveform On Transcranial Magnetic Stimulation Metrics In Proximal And Distal Arm Muscles, Christopher Lynch

Theses and Dissertations

Objectives: The purpose of this study was to determine the effect of common transcranial magnetic stimulation (TMS) waveforms (monophasic and biphasic) on resting motor threshold (RMT), active motor threshold (AMT), and motor evoked potential (MEP) amplitudes in the biceps and first dorsal interosseous (FDI) because waveforms may affect motor targets differently. Additionally, we determined the test-retest reliability of TMS metrics for each stimulation type and muscle.

Methods: Ten individuals participated in two sessions of single-pulse TMS delivered to the motor cortex perpendicular to the central sulcus. MEPs were normalized to the maximum EMG signal during contraction and were recorded at …

Assessing Heart Rate Using Consumer Technology Association Standards, Joel D. Reece, Jennifer A. Bunn, Minsoo Choi, James W. Navalta

Kinesiology and Nutrition Sciences Faculty Research

It is difficult for developers, researchers, and consumers to compare results among emerging wearable technology without using a uniform set of standards. This study evaluated the accuracy of commercially available wearable technology heart rate (HR) monitors using the Consumer Technology Association (CTA) standards. Participants (N = 23) simultaneously wore a Polar chest strap (criterion measure), Jabra Elite earbuds, Scosche Rhythm 24 armband, Apple Watch 4, and Garmin Forerunner 735 XT during sitting, activities of daily living, walking, jogging, running, and cycling, totaling 57 min of monitored activity. The Apple Watch mean bias was within ±1 bpm, and mean absolute percent …

Complementary Techniques To Study The Behavior Of Water And The Effect On Diffusion And Degradation In Hydrogels, Paige Rockwell

Master’s Theses

Hydrogels exhibit biocompatibility in a range of biomedical applications, including drug delivery. This thesis aims to develop complementary techniques to measure the diffusion and degradation behaviors within an injectable, hydrolytically degradable hydrogel, formed via the covalent crosslinking of ethoxylated trimethylolpropane tri-3- mercaptopropionate (ETTMP) and poly(ethylene glycol) diacrylate (PEGDA), to determine its suitability as a drug delivery matrix. The characterization of water as either free, within the network openings of the hydrogel, or bound, tightly associated with the polymer chains, was determined using differential scanning calorimetry (DSC). The mobility of each type of water within the hydrogels was determined via nuclear …

Improved Biochar Based Controlled-Release Nitrogen Fertilizers For Sustainable Corn Production, Robiul Islam Rubel

Electronic Theses and Dissertations

Nitrogen use efficiency (NUE) is an essential factor to increase crop yield. When conventional nitrogen fertilizer (e.g. Urea, Ammonium Sulphate, etc.) is applied in the field, generally over 50% of the N of these fertilizers may lose into the air due to vaporization, or run-off and leaching in rivers and lakes. The N losses lead to not only low NUE but also serious environmental problems. The consequence of N losses results in insufficient N available to meet the demand of crop growth at the growing stages. Lack of sufficient N for crop growth puts a threat of nutrient deficiency and …

A Step Closer To Elastogenesis On Demand; Inducing Mature Elastic Fibre Deposition In A Natural Biomaterial Scaffold, Francisco R. Almeida-González, Arlyng González-Vázquez, Suzanne M. Mithieux, Fergal J. O'Brien, Anthony S. Weiss, Claire Brougham

Articles

Elastic fibres play a key role in bodily functions where fatigue resistance and elastic recovery are necessary while regulating phenotype, proliferation and migration in cells. While in vivo elastic fibres are created at a late foetal stage, a major obstacle in the development of engineered tissue is that human vascular smooth muscle cells (hVSMCs), one of the principal elastogenic cells, are unable to spontaneously promote elastogenesis in vitro. Therefore, the overall aim of this study was to activate elastogenesis in vitro by hVSMCs seeded in fibrin, collagen, glycosaminoglycan (FCG) scaffolds, following the addition of recombinant human tropoelastin. This combination …

Intrabodies Reveal Critical Steps Involved In Ricin's Interactions With The Ribosome, Timothy Francis Czajka

Legacy Theses & Dissertations (2009 - 2024)

Ricin is a highly lethal protein toxin derived from the seeds of the castor plant, Ricinus communis. It is a Type II ribosome inactivating protein (RIP), meaning it is a heterodimer with one subunit, ricin toxin B (RTB), that mediates cell surface attachment and intracellular trafficking and a second subunit, ricin toxin A (RTA), that irreversibly shuts down protein synthesis in the cytosol. During trafficking, RTA and RTB necessarily separate in the endoplasmic reticulum, wherein RTA unfolds and translocates into the cytosol where it refolds into an enzymatically active conformation. RTA is remarkably fast acting and efficient, with few molecules …

Mapping Of Auditory Cortical Functions Using Electrocorticography, James Robert Swift

Legacy Theses & Dissertations (2009 - 2024)

Communication is a dynamic process through which we translate our inner thoughts in such a way that they can be shared with another person. This complex neurological phenomenon is a key predictor of our productivity and health. When our ability to communicate is compromised, our quality of life suffers. Although numerous methods to investigate the neuroscientific underpinnings of human language exist, our understanding of this process remains incomplete. Improving our understanding of where, when, and how auditory cortical activity occurs can enhance diagnostic techniques and improve treatment methods for neurological conditions that can impact auditory processing, such as epilepsy, or …

Fmri Feature Extraction Model For Adhd Classification Using Convolutional Neural Network, Senuri De Silva, Sanuwani Udara Dayarathna, Gangani Ariyarathne, Dulani Meedeniya, Sampath Jayarathna

Computer Science Faculty Publications

Biomedical intelligence provides a predictive mechanism for the automatic diagnosis of diseases and disorders. With the advancements of computational biology, neuroimaging techniques have been used extensively in clinical data analysis. Attention deficit hyperactivity disorder (ADHD) is a psychiatric disorder, with the symptomology of inattention, impulsivity, and hyperactivity, in which early diagnosis is crucial to prevent unwelcome outcomes. This study addresses ADHD identification using functional magnetic resonance imaging (fMRI) data for the resting state brain by evaluating multiple feature extraction methods. The features of seed-based correlation (SBC), fractional amplitude of low-frequency fluctuation (fALFF), and regional homogeneity (ReHo) are comparatively applied to …

Combining Cryo-Em Density Map And Residue Contact For Protein Secondary Structure Topologies, Maytha Alshammari, Jing He

Computer Science Faculty Publications

Although atomic structures have been determined directly from cryo-EM density maps with high resolutions, current structure determination methods for medium resolution (5 to 10 Å) cryo-EM maps are limited by the availability of structure templates. Secondary structure traces are lines detected from a cryo-EM density map for α-helices and β-strands of a protein. A topology of secondary structures defines the mapping between a set of sequence segments and a set of traces of secondary structures in three-dimensional space. In order to enhance accuracy in ranking secondary structure topologies, we explored a method that combines three sources of information: a set …

A Deep Learning Approach To Lncrna Subcellular Localization Using Inexact Q-Mer, Weijun Yi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Long non coding Ribonucleic Acids (lncRNAs) can be localized to different cellular components, such as the nucleus, exosome, cytoplasm, ribosome, etc. Their biological functions can be influenced by the region of the cell they are located. Many of these lncRNAs are associated with different challenging diseases. Thus, it is crucial to study their subcellular localization. However, compared to the vast number of lncRNAs, only relatively few have annotations in terms of their subcellular localization. Conventional computational methods use q-mer profiles from lncRNA sequences and then train machine learning models, such as support vector machines and logistic regression with the profiles. …

Restoration Of Bone Material And Microstructural Properties After Long-Term Remodeling Suppression, Abigail A. Coffman

Dissertations and Theses

Anti-resorptive drugs, principally bisphosphonates (BPs), are the mainstay of osteoporosis treatment. They work by inhibiting bone resorption/remodeling, thus preventing bone loss. However, long-term suppression of bone resorption adversely affects bone tissue mechanical properties, even while conserving bone mass. Lack of remodeling leads to accumulation of fatigue-induced microdamage, altered matrix mineralization and reduction in normal bone tissue heterogeneity, causing impaired strength and fracture toughness. The most severe consequence to patients, while rare, is Atypical Femur Fractures (i.e., complete fatigue fractures of the femoral shaft). To counteract the effects of long-term remodeling suppression, a temporary break in BP treatment (a "drug holiday) …

When The Brain Plays A Game: Neural Responses To Visual Dynamics During Naturalistic Visual Tasks, Jason Ki

Dissertations and Theses

Many day-to-day tasks involve processing of complex visual information in a continuous stream. While much of our knowledge on visual processing has been established from reductionist approaches in lab-controlled settings, very little is known about the processing of complex dynamic stimuli experienced in everyday scenarios. Traditional investigations employ event-related paradigms that involve presentation of simple stimuli at select locations in visual space and discrete moments in time. In contrast, visual stimuli in real-life are highly dynamic, spatially-heterogeneous, and semantically rich. Moreover, traditional experiments impose unnatural task constraints (e.g., inhibited saccades), thus, it is unclear whether theories developed under the reductionist …

Development Of Light Actuated Chemical Delivery Platform On A 2-D Array Of Micropore Structure, Hojjat Rostami Azmand, Hojjat Rostami Azmand

Dissertations and Theses

Localized chemical delivery plays an essential role in the fundamental information transfers within biological systems. Thus, the ability to mimic the natural chemical signal modulation would provide significant contributions to understand the functional signaling pathway of biological cells and develop new prosthetic devices for neurological disorders. In this paper, we demonstrate a light-controlled hydrogel platform that can be used for localized chemical delivery in a high spatial resolution. By utilizing the photothermal behavior of graphene-hydrogel composites confined within micron-sized fluidic channels, patterned light illumination creates the parallel and independent actuation of chemical release in a group of fluidic ports. The …

Assessing Midbrain Abnormalities In Parkinson’S Disease Using Magnetic Resonance Imaging, Kiarash Ghassaban

Wayne State University Dissertations

Diagnosing early-stage Parkinson’s disease (PD) and its manifestations is still a clinical challenge. Previous imaging studies using iron, neuromelanin (NM) and the Nigrosome-1 (N1) measures in the substantia nigra (SN) by themselves have been unable to provide sufficiently high diagnostic performance for these methods to be adopted clinically. In this dissertation, we start by studying idiopathic PD patients at their intermediate stages of the disease to evaluate the role of global and regional iron in the major deep gray matter nuclei. Then, we only focus on the NM complex in the midbrain and how neuronal loss interact with iron overload …

Als-Induced Excitability Changes In Individual Motorneurons And The Spinal Motorneuron Network In Sod1-G93a Mice At Symptom Onset, Christiana S.I. Draper

Browse all Theses and Dissertations

Amyotrophic lateral sclerosis (ALS) is the most common motorneuron (MN) disease in adulthood. ALS is hallmarked by the progressive loss of MNs in the brain, brainstem, and spinal cord. Many hypotheses to explain the pathogenesis of ALS have been explored, but the exact mechanisms underlying the development of this disease remain unknown. However, abnormalities in MN excitability and glutamate excitotoxicity are the most widely studied. For decades, researchers have examined MN excitability in ALS, but the current literature is inconsistent, showing evidence of hyperexcitability, hypoexcitability, or no change in excitability of MNs in ALS. Many of these studies also focus …

การพัฒนาเพื่อเพิ่มสมรรถนะของอุปกรณ์ทดสอบภูมิแพ้ทางผิวหนังประเภทพลาสติก, มุธิตา เจียระไนรุ่งโรจน์

Chulalongkorn University Theses and Dissertations (Chula ETD)

โรคภูมิแพ้ (Allergy) เป็นโรคที่พบได้บ่อยและมีผลกระทบสูงทั้งทางเศรษฐกิจและสังคม กระบวนการวินิจฉัยโรคภูมิแพ้ที่เป็นที่นิยมที่สุดในปัจจุบันคือการทดสอบที่ผิวหนังด้วยวิธี Skin prick test (SPT) อย่างไรก็ดีประสิทธิภาพของการทดสอบ SPT ขึ้นอยู่กับความเชี่ยวชาญ และ ประสบการณ์ของแพทย์ผู้ทำการทดสอบ ซึ่งพบว่ามีปัจจัยหลายประการที่ส่งผลต่อประสิทธิภาพในการทดสอบ เช่น ประเภทของอุปกรณ์ ประเภทของวัสดุ และแรงกด เป็นต้น ดังนั้นงานวิจัยจึงมีวัตถุประสงค์ในการศึกษาถึงผลกระทบของปัจจัยต่างๆ ที่ส่งผลต่อประสิทธิภาพในการทดสอบ SPT เพื่อการพัฒนาต่อยอดอุปกรณ์ทดสอบภูมิแพ้ที่มีประสิทธิภาพสูงโดยเฉพาะอย่างยิ่งที่สร้างจากพลาสติก โดยผู้วิจัยได้ทำการศึกษาเปรียบเทียบประสิทธิภาพของอุปกรณ์ทดสอบภูมิแพ้ทางผิวหนังที่มีจำหน่ายในท้องตลาดจำนวน 2 ชนิด คือ ALK lancet และ Feather Lancet และ อุปกรณ์ที่สร้างขึ้นจากการฉีดพลาสติกจำนวน 2 ชนิด (Prototype) ด้วยแรงกด 3 แรง คือ 30, 45 และ 60 กรัม กับอาสาสมัครจำนวน 12 คนโดยผู้ทดสอบเพียงคนเดียวในลักษณะสุ่มจุดเจาะ และเปรียบเทียบกับวิธีการมาตรฐานที่ใช้ ALK และ Needle ในการสะกิดโดยแพทย์ผู้เชี่ยวชาญ โดยใช้สารควบคุมบวก Histamine ความเข้มข้น 10 มก./มล และสารควบคุมลบคือ Normal Saline จากการทดลองกับผู้เข้ารับการทดสอบทั้งสิ้น 12 คน พบว่า ขนาดเฉลี่ยของตุ่มบวมโดยใช้อุปกรณ์ทั้ง 4 ประเภทมีขนาดที่เพิ่มขึ้นตามแรงกด โดยที่แรง 30, 45 และ 60 กรัม ตุ่มบวมมีขนาด 2.70 - 4.31 มม., 3.81 - 4.80 มม. และ 4.30 - 5.28 มม. ตามลำดับ และขนาดของตุ่มบวมของมีความแปรปรวนต่ำ ในขณะที่ขนาดเฉลี่ยของตุ่มบวมโดยวิธีการมาตรฐานทั้ง 2 วิธี คือ ALK และ Needle มีขนาดที่ใหญ่กว่าที่ 5.49 …

Multi-Label Classification On Locally-Linear Data: Application To Chemical Toxicity Prediction, Xiu Huan Yap

Browse all Theses and Dissertations

Computational models may assist in identification and prioritization of large chemical libraries. Recent experimental and data curation efforts, such as from the Tox21 consortium, have contributed towards toxicological datasets of increasing numbers of chemicals and toxicity endpoints, creating a golden opportunity for the exploration of multi-label learning and deep learning approaches in this thesis. Multi-label classification (MLC) methods may improve model predictivity by accounting for label dependence. However, current measures of label dependence, such as correlation coefficient, are inappropriate for datasets with extreme class imbalance, often seen in toxicological datasets. In this thesis, we propose a novel label dependence measure …