Biomedical Engineering and Bioengineering Commons^™

Real Time Evaluation Of Tissue Optical Properties During Thermal Ablation Of Ex Vivo Liver Tissues, Vivek K. Nagarajan, Venkateswara R. Gogineni, Sarah B. White, Bing Yu

Biomedical Engineering Faculty Research and Publications

Complete ablation of liver tumors is vital for minimizing the risk of local tumor recurrence. Accurately identifying the hallmarks of tissue necrosis during thermal ablative therapies may significantly increase the efficacy of ablation, while minimizing unnecessary damage to the surrounding normal tissues or critical structures. Light propagation in biological tissues is sensitive to the tissue microstructure and chromophore concentrations. In our previous studies, we found that the wavelength (λ) averaged liver tissue absorption coefficient μ_a and reduced scattering coefficient μ_s’ change significantly upon heating which may be used for assessment of tissue damage during thermal …

Opioids Delay Healing Of Spinal Fusion: A Rabbit Posterolateral Lumbar Fusion Model, Nikhil Jain, Khaled Himed, Jeffrey M. Toth, Karen C. Briley, Frank M. Phillips, Safdar N. Khan

Biomedical Engineering Faculty Research and Publications

Background Context

Opioid use is prevalent in the management of pre- and postoperative pain in patients undergoing spinal fusion. There is evidence that opioids downregulate osteoblasts in vitro, and a previous study found that morphine delays the maturation and remodeling of callus in a rat femur fracture model. However, the effect of opioids on healing of spinal fusion has not been investigated before. Isolating the effect of opioid exposure in humans would be limited by the numerous confounding factors that affect fusion healing. Therefore, we have used a well-established rabbit model to study the process of spinal fusion healing that …

Use Of A Dynamic Balance System To Quantify Postural Steadiness And Stability Of Individuals With Lower-Limb Amputation: A Pilot Study, M. Barbara Silver-Thorn Phd, Joel Kempfer, Alyssa J. Schnorenberg, Brooke Slavens

Biomedical Engineering Faculty Research and Publications

Introduction Despite rehabilitation and gait training, the gait of individuals with lower-limb amputation is often asymmetric and falls and/or fear of falling are common. Clinical assessments of balance and stability include the Berg BalanceScale and the Dynamic Gait Index. Biomechanical assessments, conducted largely in research laboratories, are more objective, quantitative, and may provide greater resolution. These biomechanical measures include postural sway during both unilateral and bilateral standing tasks and the dynamic postural response to applied or volitional perturbations. The objective of this study was to investigate the utility of a dynamic balance system, a relatively new clinical tool incorporating dual …

Mechanical And Material Characterization Of Advanced Materials For Tissue Regeneration, Bailey Kylara Ricketts Jackson

Theses and Dissertations

In natural disasters and military deployment operations, injury to long bone can cause extensive damage and be difficult to treat and heal quickly. Explosive devices and trauma often produce long-bone (>2-cm length) wounds that are more complicated than common fractures. Due to the size and complexity of these injuries, they can be difficult to treat in a battlefield environment and take a long time to heal completely and properly. Even after the long healing period, these injuries often require rehabilitation to strengthen the muscles that have weakened in the wounded limb. For military applications especially, these effects can put …

Biom 3110: Medical Physiology (Syllabus), Bradford D. Pendley

Biomedical Engineering Syllabi Archive

Course Description: Basic principles of human physiology and how these are applied in medicine and biomedical engineering problem and devices; physiological principles using appropriate mathematical and engineering models to construct an understanding of how the body works as an integrated system.

In Vivo Raman Spectroscopy For Biochemical Monitoring Of The Human Cervix Throughout Pregnancy, Christine M. O'Brien, Elizabeth Vargis, Amy Rudin, James C. Slaughter, Giju Thomas, J. Michael Newton, Jeff Reese, Kelly A. Bennett, Anita Mahadevan-Jansen

Biological Engineering Faculty Publications

Background

The cervix must undergo significant biochemical remodeling to allow for successful parturition. This process is not fully understood, especially in instances of spontaneous preterm birth. In vivo Raman spectroscopy is an optical technique that can be used to investigate the biochemical composition of tissue longitudinally and noninvasively in human beings, and has been utilized to measure physiology and disease states in a variety of medical applications.

Objective

The purpose of this study is to measure in vivo Raman spectra of the cervix throughout pregnancy in women, and to identify biochemical markers that change with the preparation for delivery and …

Early Emerging Pathogen Detection, Mackenzie Wangenstein

Maseeh Summer Undergraduate Research Experience

A supervised learning technique was employed to identify emerging pathogen species. Portland State University has partnered with the University of New Mexico to take encodings of unknown pathogen molecular structures to determine emerging species.

Surface Functionalization Via Photoinitiated Radical Polymerization For Rare Cell Isolation And Mechanical Protection, Calvin Frank Cahall

Theses and Dissertations--Chemical and Materials Engineering

Surface functionalization of living cells for cell therapeutics has gained substantial momentum in the last two decades. From encapsulating islets of Langerhans, to cell laden gels for tissue scaffolds, to individual cell encapsulation in thin hydrogels, to surface adhesives and inert surface camouflage, modification of living cell surfaces has a wide array of important applications. Here we use hydrogel encapsulation of individual cells as a mode of protection from mechanical forces for high throughput cell printing, and chemical stimuli for the isolation of rare cells in blood.

In the first study, we review methods of surface functionalization and establish a …

Design And Development Of A Compact X-Ray Tube For Stationary Ct Architecture, Ashish Vighnahar Avachat

Doctoral Dissertations

"Multisource architectures enable sweeping one or more x-ray beams across the imaging field-of-view faster than physically moving a single x-ray source and/or a detector. Hence, these architectures are attractive for the applications in which temporal resolution plays an important role, for example, cardiac computed tomography (CT) or real-time CT. One of the recent developments in multisource architectures for CT imaging is stationary CT architecture, whereby two separate stationary arrays -- one for x-ray sources and one for detectors -- are utilized to sweep one or more x-ray beams along the gantry and acquire 360 degree projections. To have a stationary …

Cementless Tibial Base Micromotion During Activities Of Daily Living, Hayden Wilson

Electronic Theses and Dissertations

Initial stability of cementless total knee replacement (TKR) components is directly related to long-term fixation and success, as excess motion hinders bony ingrowth. To assess implant stability, there is a need for more physiologically accurate loading conditions, incorporating forces and displacements in all 6 degrees-of-freedom found in the knee joint, as well as understanding the impact of femoral flexion on conformity of tibiofemoral articulation. Understanding how different activities of daily living generate tibial micromotion yields insight into surgical technique considerations, and rehabilitation strategies post-operatively. ASTM F3141-15, which specifies knee flexion, Internal-External moment, Medial-Lateral, Anterior-Posterior and Superior-Inferior forces during gait and …

Matrix Stiffness Modulates Mesenchymal Stem Cell Sensitivity To Geometric Asymmetry Signals, Maria Eugenia Piroli

Theses and Dissertations

Human stem cells hold significant potential for the treatment of various diseases. However, their use as a therapy is hampered by the limited understanding of the mechanisms by which stem cells respond to environmental stimuli. Efforts to understand extracellular biophysical cues have demonstrated the critical roles of geometric and mechanical signals in determining the fate of stem cells. The goal of this study was to explore the interplay between cell polarity and matrix stiffness in stem cell lineage specification. We hypothesize that confining cells to asymmetric extracellular matrix (ECM) islands will impart polarity at a single-cell level and result in …

Plants As Biofactories To Produce Mammalian Tumor Suppressor Micrornas, John Lachlan Macarthur

Theses and Dissertations

MicroRNAs (miRNAs) are small noncoding single stranded RNAs that are considered master regulators of gene expression. They are also an emerging class of therapeutic agents with significant potential for the prevention and treatment of many diseases, including cancer. Many different forms of cancer are associated with loss or reduced accumulation of one or more miRNAs that function as tumor suppressors. In animal models, restoration of missing tumor suppressor miRNAs prevents the initiation, progression and/or spread of the disease. However, the current absence of an efficient method for delivery of therapeutic miRNAs is a critical barrier to their use. The research …

Modulation Of Amyloid-Β Aggregation Via Small Molecules And Glycine Zipper Alterations, Steven Zebulon Vance

Theses and Dissertations

Alzheimer’s disease (AD) is the most common form of neurodegenerative disease. Nationally, AD is the 6th leading cause of death and the only top 10 killer of Americans that cannot be slowed, cured, or prevented. AD is characterized by the deposition of extracellular plaques of aggregated amyloid-β protein (Aβ). Aβ originates from the amyloid precursor protein (APP), a transmembrane protein that is cleaved to form a short and inert protein fragment called Aβ. However, Aβ undergoes a nucleation process wherein aggregates from soluble oligomers to insoluble fibrils are formed. While uncertainty remains as to the exact mechanism, studies have associated …

Changes Of Dispersal Ability In An Isolated Population, Connor Bacon

Theses and Dissertations

Dispersal is a core mechanism in the maintenance of metapopulations. It maintains genetic diversity by connecting subpopulations and generates new populations to replace those that die out. However, as populations become more isolated, as occurs in habitat fragmentation, dispersal becomes more difficult. This should lead to selective pressure against dispersive individuals, causing a reduction in dispersal traits. Over time, this can lead to variation in dispersal traits among populations. We examine this idea using an extreme case of isolation in Euphydryas gillettii, a population that has remained completely isolated for forty years. By comparing this population to a baseline established …

Screening Of Novel Active Salicylic Acid Analogs And Identification Of A Bacterial Effector Targeting Key Proteins Involved In Salicylic Acid-Mediated Defense, Ian Palmer

Theses and Dissertations

The master regulator of salicylic acid (SA)-mediated plant defense, NPR1 (NONEXPRESSER OF PR GENES 1), and its paralogs NPR3 and NPR4 act as SA receptors. After the perception of a pathogen, plant cells produce SA in the chloroplast. In the presence of SA, NPR1 protein is reduced from oligomers to monomers, and translocated into the nucleus. There, NPR1 binds to TGA and WRKY transcription factors to induce expression of plant defense genes. EDS1 and PBS3 are two key proteins involved in SA biosynthesis. Previous research has shown that several plant pathogens produce SA hydroxylases. These pathogen-produced hydroxylases act to degrade …

A Comprehensive Reengineering Of The Hospital Emergency Triage System, Nicholas D. Boltin

Theses and Dissertations

Hospital emergency triage and specifically Mass Casualty Incidents (MCIs) are of major concern with regard to treatment and patient outcomes. Traditional emergency department triage models are oversimplified and often lead to over/under triaging of patients. Furthermore, triage models do not account for the full spectrum of different types of MCIs which often results in misclassification. In this thesis, we begin by looking at traditional triage models currently being used in hospital systems and identify several shortcomings of using these models within the context of a chemical related MCI. I will then move to describe a new approach to creating a …

Changes In Nadph Oxidase (Nox) Protein Isoforms And Downstream Reactions As Function Of Time And Overpressure In Blast Tbi, Smit Prakash Shah

Theses

Blast-induced Traumatic brain injury (bTBI) is a leading cause of morbidity in soldiers on the battlefield and training sites with long-term neurological and psychological pathologies. Among many pathological sequela of blast TBI, oxidative stress has been identified as a major factor contributing to the pathophysiology of bTBI. Recent studies have demonstrated activation of oxidative stress pathways following blast injury but their distribution among different brain regions as function of post injury time and Blast over pressure (BOP) have not been explored. The present study examines the protein expression of NADP oxidase (NOX) isoforms 1 & 2, corresponding superoxide production, a …

Association Between Mechanics And Biology In Vascular Graft Remodeling, David Andrew Prim

Theses and Dissertations

Coronary artery bypass grafting (CABG) restores myocardial perfusion in patients with severe coronary artery disease by utilizing autografts – usually at least one of the internal thoracic artery (ITA), radial artery (RA), and great saphenous vein (GSV) – to bypass stenosed regions of coronary arteries. While decades of research and clinical improvements have made CABG an indispensable procedure, tens of thousands of grafts fail each year, which is due, at least in part, to an inability of the source vessels to adapt to the altered stimuli of the coronary circulation. In this dissertation, we first quantify and compare the mechanical …

การพัฒนาระบบตรวจวัดแคลเซียมออกซาเลตในปัสสาวะเพื่อการคัดกรองโรคนิ่วไต, พิชญุตม์ ฤกษนันทน์

Chulalongkorn University Theses and Dissertations (Chula ETD)

วิทยานิพนธ์นี้ได้ทำการพัฒนาระบบตรวจคัดกรองผู้ที่มีโอกาสเสี่ยงต่อโรคนิ่วไต (Kidney stone disease) โดยใช้วิธี Indole Calcium Oxalate Crystalization Index : iCOCI ซึ่งเป็นการตรวจวัดความเข้มสีที่เกิดจากปฏิกิริยาระหว่างออกซาเลตในปัสสาวะกับสาร Indole reagent โดยได้ทำการศึกษาถึงตัวแปรต่าง ๆ ที่มีผลต่อการวัดเพื่อปรับปรุงประสิทธิภาพของวิธี iCOCI ซึ่งพบว่าสามารถลดเวลาในขั้นตอนการบ่มปัสสาวะได้เหลือเพียง 10 นาที และการใช้ Indole reagent ที่ความเข้มข้น 2.5 mg/ml สามารถให้ความแยกชัดในการตรวจคัดกรองได้สูงที่สุด จากนั้นได้ทำการทดสอบประสิทธิภาพของการตรวจคัดกรองโดยนำตัวอย่างปัสสาวะของกลุ่มผู้ที่มีสุขภาพดีและกลุ่มผู้ป่วยโรคนิ่วไต กลุ่มล่ะ 60 ตัวอย่างมาทำการตรวจวัดโดยใช้วิธี iCOCI ร่วมกับระบบวัดทางแสงที่พัฒนาขึ้นโดยใช้เซนเซอร์อาเรย์ที่ตอบสนองต่อแสงที่ความยาวคลื่นต่าง ๆ ซึ่งพบว่าการใช้ค่าการดูดกลืนแสงของสารตัวอย่างที่ความยาวคลื่น 600 nm จะสามารถให้ประสิทธิภาพของการตรวจคัดกรองได้สูงสุดคือได้ค่าความไวและความจำเพาะในการตรวจคัดกรองมากกว่า 70% ซึ่งเพียงพอต่อการนำไปใช้งานเพื่อตรวจคัดกรองในทางคลีนิค นอกจากนี้ยังได้ทำการพัฒนาระบบผสมและนำส่งสาร และระบบแปลและแสดงผลการตรวจคัดกรองเพื่อทดสอบความเป็นไปได้ในการนำไปพัฒนาเป็นระบบแบบอัตโนมัติโดยใช้ไมโครคอนโทรลเลอร์ในการควบคุม ซึ่งจากการทดสอบพบว่าระบบทั้งหมดที่พัฒนาขึ้นสามารถนำไปใช้ในการตรวจวัดที่ใกล้เคียงกับการนำไปใช้งานจริงนอกสถานพยาบาลได้อย่างเหมาะสม จึงทำให้มีความเป็นไปได้ในการนำระบบที่ได้พัฒนาขึ้นนี้ไปใช้ในการตรวจคัดกรองโรคนิ้วไตแบบไม่รุกล้า (Non-invasive) ได้ต่อไป

การเตรียมโครงเลี้ยงเซลล์จากไฟโบรอินไหมไทยและไบโอแอคทีฟกลาสเพื่องานวิศวกรรมเนื้อเยื่อกระดูก, พิมพ์นารา วัฒนะชัย

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อเตรียมโครงเลี้ยงเซลล์สำหรับงานวิศวกรรมเนื้อเยื่อกระดูก โดยใช้ไฟโบรอินไหมไทย (SF) และไบโอแอคทีฟกลาส (BG) เชื่อมขวางด้วย 3-ไกลซิดอกซีโพรพิลไตรเอทอกซีไซเลน ((3-Glycidoxypropyl)trimethoxysilane; GPTMS) และขึ้นรูปด้วยวิธีโฟมมิง (Foaming) ผลการวิเคราะห์โครงสร้างทางเคมีด้วยเทคนิค FTIR ยืนยันการเชื่อมขวางระหว่าง SF และ BG เมื่อทดสอบการรับแรงกด พบว่าโครงเลี้ยงเซลล์ผสม SF-BG มีมอดูลัสการกดเพิ่มขึ้นจากโครงเลี้ยงเซลล์ SF ถึง 11 เท่า และไม่มากเกินมอดูลัสของกระดูกจริงดังเช่นโครงเลี้ยงเซลล์ BG ทั้งนี้เสถียรภาพของโครงเลี้ยงเซลล์ผสมที่เชื่อมขวางทั้งสภาวะในน้ำหรือในสารละลายเอนไซม์โปรติเอส XIV ดีกว่าเสถียรภาพของโครงเลี้ยงเซลล์ SF และโครงเลี้ยงเซลล์ผสมที่ไม่ผ่านการเชื่อมขวาง เมื่อทดสอบความไม่เป็นพิษต่อเซลล์ตาม ISO 10993 part 5 พบว่าโครงเลี้ยงเซลล์ผสมไม่มีความเป็นพิษ และผลการทดสอบฤทธิ์ชีวภาพในห้องปฏิบัติการโดยใช้เซลล์กระดูก (SaOS-2 cell line) พบว่าโครงเลี้ยงเซลล์ผสมมีความสามารถในการส่งเสริมการสร้างกระดูก เมื่อพิจารณาจากผลการยึดเกาะ การเจริญเติบโต ระดับกิจกรรมของเอนไซม์แอลคาไลน์ฟอสฟาเตส ปริมาณแคลเซียมที่สะสมภายในเซลล์ และปริมาณแคลเซียมที่ตกตะกอนลงบนโครงเลี้ยงเซลล์ ดังนั้นโครงเลี้ยงเซลล์ผสมชนิดใหม่จาก SF และ BG มีศักยภาพในการใช้เป็นโครงเลี้ยงเซลล์สำหรับงานวิศวกรรมทางเนื้อเยื่อต่อไปในอนาคต