Mechanical Engineering Commons^™

Model-Based Comparison Of Biological Organism And Electro-Mechanical System Resiliency Strategies, Nicholas Ratycz

Mechanical Engineering Undergraduate Honors Theses

Bio-inspired design has been used by many engineers to solve difficult problems or to make manufacturing processes more efficient. Biomimetics is the study of implementing the structure or function of biological substances, materials, mechanisms, and processes onto artificial ones that mimic the original. The goal of the BIASD tool is to provide bio-inspiration for engineers by studying the fault-adaptive strategies that biological systems use, rather than just their structure or function. In this thesis, the fault adaptive strategies of both a biological example and that of a real cubesat are compared using three types of model-based system diagrams to show …

Reducing Food Scarcity: The Benefits Of Urban Farming, S.A. Claudell, Emilio Mejia

Journal of Nonprofit Innovation

Urban farming can enhance the lives of communities and help reduce food scarcity. This paper presents a conceptual prototype of an efficient urban farming community that can be scaled for a single apartment building or an entire community across all global geoeconomics regions, including densely populated cities and rural, developing towns and communities. When deployed in coordination with smart crop choices, local farm support, and efficient transportation then the result isn’t just sustainability, but also increasing fresh produce accessibility, optimizing nutritional value, eliminating the use of ‘forever chemicals’, reducing transportation costs, and fostering global environmental benefits.

Imagine Doris, who is …

Du Undergraduate Showcase: Research, Scholarship, And Creative Works, Caitlyn Aldersea, Justin Bravo, Sam Allen, Anna Block, Connor Block, Emma Buechler, Maria De Los Angeles Bustillos, Arianna Carlson, William Christensen, Olivia Kachulis, Noah Craver, Kate Dillon, Muskan Fatima, Angel Fernandes, Emma Finch, Colleen Cassidy, Amy Fishman, Andrea Francis, Stacia Fritz, Simran Gill, Emma Gries, Rylie Hansen, Shannon Powers, Jacqueline Martinez, Zachary Harker, Ashley Hasty, Mykaela Tanino-Springsteen, Kathleen Hopps, Adelaide Kerenick, Colin Kleckner, Ci Koehring, Elijah Kruger, Braden Krumholz, Maddie Leake, Lyneé Alves, Seraphina Loukas, Yatzari Lozano Vazquez, Haley Maki, Emily Martinez, Sierra Mckinney, Mykaela Tanino-Springsteen, Audrey Mitchell, Kipling Newman, Audrey Ng, Megan Lucyshyn, Andrew Nguyen, Stevie Ostman, Casandra Pearson, Alexandra Penney, Julia Gielczynski, Tyler Ball, Anna Rini, Christina Rorres, Simon Ruland, Helayna Schafer, Emma Sellers, Sarah Schuller, Claire Shaver, Kevin Summers, Isabella Shaw, Madison Sinar, Claudia Pena, Apshara Siwakoti, Carter Sorensen, Madi Sousa, Anna Sparling, Alexandra Revier, Brandon Thierry, Dylan Tyree, Maggie Williams, Lauren Wols

DU Undergraduate Research Journal Archive

DU Undergraduate Showcase: Research, Scholarship, and Creative Works

E-Cadherin Force Transmission And Stiffness Sensing, Mazen Mezher

Mechanical & Aerospace Engineering Theses & Dissertations

E-cadherin is the chief mediator of cell-cell adhesion between epithelial cells and is a known mechanosensor. Force transmission and stiffness sensing are two crucial aspects of E-cadherin mechanobiology.

E-cadherin has an extracellular adhesive region, a transmembrane region and an intracellular region that binds to adhesion-associated proteins. Here, we assessed how different factors affect the level of force transmission (i) from inside the cell such as adhesion-associated proteins, (ii) on the cell membrane, such as growth factor receptors and (iii) outside the cell, such as different binding partners in adhesion. To study the level of force transmission inside the cell, we …

Characterizing Mechanical Regulation Of Bone Metastatic Breast Cancer Cells, Boyuan Liu

Doctoral Dissertations

Breast cancer most frequently metastasizes to the skeleton. Bone metastatic cancer is incurable and induces wide-spread bone osteolysis, resulting in significant patient morbidity and mortality. Mechanical stimuli in the skeleton are an important microenvironmental parameter that modulates tumor formation, osteolysis, and tumor cell-bone cell signaling, but which mechanical signals are the most beneficial and the corresponding molecular mechanisms are unknown. This work focused on bone matrix deformation and interstitial fluid flow based on their well-known roles in bone remodeling and in primary breast cancer. The goal of our research was to establish a platform that could define the relationship between …

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 …

Broadening The Capability Of Kinetics Analysis In Biomechanics, Nicholas Nelson

Electronic Theses and Dissertations

Two studies are discussed in this manuscript each preceded by a literature review of the topic. The first review and study explore agility movements and the effect that alternative upper designs in shoes might have on ground reaction force measures of performance. The second review and study evaluate methods of predicting ground reaction forces without the use of a force platform. A method of using effective forces and ways of improving its accuracy are evaluated in depth.

Biodiesel Production From Chicken Feather Meal And Its Performance Analysis On Diesel Engine, Venkateswarulu Tc, Indira Mikkili, Krupanidhi Srirama, Nazneen Bobby Md., John Babu Dulla, Venkata Narayana Alugunulla, Vivekananda S, Abraham Peele, Bangaraiah P

Karbala International Journal of Modern Science

Biodiesel has intrinsic lubricating properties due to the presence of long chain fatty acids, which significantly help to reduce engine wear and tear. Poultry waste as an alternative energy source could aid in reducing greenhouse gases. Biodiesel acknowledges environmental issues as it is less toxic than diesel and is biodegradable too. It is much safer to handle due to its high flash point and consequently, air quality improves dramatically. From the energy point of view, as a renewable source of energy, it helps in energy conservation and ensures regular availability for production of fuel. The chicken feather meal with moderate …

Investigation Of The Electrode Polarization Effect For Biosensor Applications, Anil Koklu

Mechanical Engineering Research Theses and Dissertations

My research focuses on electrokinetic transport. Particularly, in this dissertation, we focus on fabrication and testing of micro electrodes with nanostructured surfaces to minimize the electrode polarization (EP) effects for biosensor applications. In the first study, electrochemical deposition of gold nanoparticles on to planar gold electrodes was used to generate rough surfaces. Dendritic nanostructures that reduced EP up to two orders of magnitude was obtained by optimizing the deposition conditions. These structures also enhanced dielectrophoresis (DEP) response of our bio-chips, making them usable in physiological buffers. In further studies we discovered a universal scaling of EP in the frequency domain, …

Endogenous Force Transmission Between Epithelial Cells And A Role For Α-Catenin, Sandeep Dumbali

Mechanical & Aerospace Engineering Theses & Dissertations

In epithelial tissues, epithelial cells adhere to each other as well as to the underlying extra-cellular matrix (ECM). E-cadherin-based intercellular junctions play an important role in tissue integrity. These junctions experience cell-generated mechanical forces via apparent adaptor proteins such as beta (β) catenin, alpha (α) catenin and vinculin. Abnormalities in these junctions may result in skin related diseases and cancers. Here, I devised methods to determine the endogenous intercellular force within cell pairs as well as in large epithelial islands. I further ascertained the factors that affect the level of inter-cellular tension.

Experiments with pairs of epithelial cells exogenously expressing …

Maximizing And Modeling Malonyl-Coa Production In Escherichia Coli, Tatiana Thompson Silveira Mello

LSU Master's Theses

In E. coli, fatty acid synthesis is catalyzed by the enzyme acetyl-CoA carboxylase (ACC), which converts acetyl-CoA into malonyl-CoA. Malonyl-CoA is a major building block for numerous of bioproducts. Multiple parameters regulate the homeostatic cellular concentration of malonyl-CoA, keeping it at a very low level. Understanding how these parameters affect the bacterial production of malonyl-CoA is fundamental to maximizing it and its bioproducts. To this end, competing pathways consuming malonyl-CoA can be eliminated, and optimal nutritional and environmental conditions can be provided to the fermentation broth. Most previous studies utilized genetic modifications, expensive consumables, and high-cost quantification methods, making …

Modeling Mechanisms Behind Force Generation By Actin Polymerization, Seyed Fowad Motahari

Arts & Sciences Electronic Theses and Dissertations

Actin polymerization is the primary mechanism for overcoming the large turgor pressure that opposes endocytosis in yeast. While generation of pushing forces by actin polymerization is fairly well understood, it is not clear how actin polymerization produces pulling forces. In order to understand this process, it is necessary to simulate polymerization of filaments having various types of interactions with the membrane. Since existing methodologies in the literature do not treat such problems correctly, we develop a thermodynamically consistent methodology for treating polymerization of filaments having arbitrary interaction potentials with the membrane. Then I perform stochastic simulations for a system of …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi S. Patel

University Scholar Projects

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi Patel

Honors Scholar Theses

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Accurate Flexible Refinement Of Atomic Models Against Medium-Resolution Cryo-Em Maps Using Damped Dynamics, Julio A. Kovacs, Vitold E. Galkin, Willy Wriggers

Mechanical & Aerospace Engineering Faculty Publications

Background: Dramatic progress has recently been made in cryo-electron microscopy technologies, which now make possible the reconstruction of a growing number of biomolecular structures to near-atomic resolution. However, the need persists for fitting and refinement approaches that address those cases that require modeling assistance.

Methods: In this paper, we describe algorithms to optimize the performance of such medium-resolution refinement methods. These algorithms aim to automatically optimize the parameters that define the density shape of the flexibly fitted model, as well as the time-dependent damper cutoff distance. Atomic distance constraints can be prescribed for cases where extra containment of parts of …

Effects Of Malformed Or Absent Valves To Lymphatic Fluid Transport And Lymphedema In Vivo In Mice, Akshay S. Pujari

Masters Theses

Lymph is primarily composed of fluid and proteins from the blood circulatory system that drain into the space surrounding cells, interstitial space. From the interstitial space, the fluid enters and circulates in the lymphatic system until it is delivered into the venous system. In contrast to the blood circulatory system, the lymphatic system lacks a central pumping organ dictating the predominant driving pressure and velocity of lymph. Transport of lymph via capillaries, pre-collecting and collecting lymphatic vessels relies on the synergy between pressure gradients, local tissue motion, valves and lymphatic vessel contractility. The direction of lymph transport is regulated by …

Bacterial Motility And Its Role In Biofilm Formation, Clayton J. Culp, Arezoo M. Ardekani, Adib Ahmadzadegan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Bacterial biofilms are known to cause millions of dollars in damage in the medical industry per year via infection of central venous catheters, urinary catheters, and mechanical heart valves. Unfortunately, there are some characteristics of biofilm formation that are yet to be fully understood. Recently much work has been done to investigate the motility characteristics of bacteria with hopes of better understanding the phenomena of biofilm formation. Still, one of the least understood stages is bacterial attachment or adhesion, a process designed to anchor bacteria in an advantageous environment. Providing a better understanding of bacterial motility near solid interfaces will …

Biophysical Tools To Study Cellular Mechanotransduction, Ismeel Muhamed, Farhan Chowdhury, Venkat Maruthamuthu

Mechanical & Aerospace Engineering Faculty Publications

The cell membrane is the interface that volumetrically isolates cellular components from the cell's environment. Proteins embedded within and on the membrane have varied biological functions: reception of external biochemical signals, as membrane channels, amplification and regulation of chemical signals through secondary messenger molecules, controlled exocytosis, endocytosis, phagocytosis, organized recruitment and sequestration of cytosolic complex proteins, cell division processes, organization of the cytoskeleton and more. The membrane's bioelectrical role is enabled by the physiologically controlled release and accumulation of electrochemical potential modulating molecules across the membrane through specialized ion channels (e.g., Na^⁺, Ca²⁺, K^⁺ channels). …

Three-Dimensional Confocal Microscopy Indentation Method For Hydrogel Elasticity Measurement, Donghee Lee, Md Mahmudur Rahman, You Zhou, Sangjin Ryu

Md Mahmudur Rahman

No abstract provided.

Structure-Functionality Relationship Of Collagen Scaffolds For Tissue Engineering, Seungman Park

Open Access Dissertations

Tissue engineering is a promising technology that enables scientists to create artificial organs or replace damaged tissues using animal cells and other components. For successful tissue regeneration, many factors should be taken into account, however, three components are most crucial: cell, scaffold, and soluble factor(s). In order to check the functionality after regeneration of desired tissues, various approaches have been attempted, depending on the physical, biological, and chemical properties of the tissues. Recently, the importance of the extracellular matrix (ECM) microstructure is being considered to be important in this regard. The ECM is closely associated with various functional properties of …

Understanding Preferred Leg Stiffness And Layered Control Strategies For Locomotion, Zhuohua H. Shen

Open Access Dissertations

Despite advancement in the field of robotics, current legged robots still cannot achieve the kind of locomotion stability animals and humans have. In order to develop legged robots with greater stability, we need to better understand general locomotion dynamics and control principles. Here we demonstrate that a mathematical modeling approach could greatly enable the discovery and understanding of general locomotion principles. ^ It is found that animal leg stiffness when scaled by its weight and leg length falls in a narrow region between 7 and 27. Rarely in biology does such a universal preference exist. It is not known completely …

Toward Direct Biosynthesis Of Drop-In Ready Biofuels In Plants: Rapid Screening And Functional Genomic Characterization Of Plant-Derived Advanced Biofuels And Implications For Coproduction In Lignocellulosic Feedstocks, Blake Lee Joyce

Doctoral Dissertations

Advanced biofuels that are “drop-in” ready, completely fungible with petroleum fuels, and require minimal infrastructure to process a finished fuel could provide transportation fuels in rural or developing areas. Five oils extracted from Pittosporum resiniferum, Copaifera reticulata, and surrogate oils for Cymbopogon flexuosus, C. martinii, and Dictamnus albus in B20 blends were sent for ASTM International biodiesel testing and run in homogenous charge combustion ignition engines to determine combustion properties and emissions. All oils tested lowered cloud point. Oils derived from Copaifera reticulata also lowered indicated specific fuel consumption and had emissions similar to the ultra-low sulfur diesel control. Characterization …

Inhibition Of Bacillus Cereus Growth By Bacteriocin Producing Bacillus Subtilis Isolated From Fermented Baobab Seeds (Maari) Is Substrate Dependent, Donatien Kaboré, Dennis S. Nielsen, Hagrétoui Sawadogo-Lingan, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jakobsen, Line Thorsen

Pr. Mamoudou H. DICKO, PhD

Valence-Length Correlations For Chemical Bonds From Atomic Orbital Exponents, F. D. Hardcastle

Journal of the Arkansas Academy of Science

Pauling’s empirical bond valence-length correlation has proven valuable because it offers a quick and convenient way of checking and evaluating molecular structures and determining oxidation states from measured bond lengths. In this study, a simplified quantum-mechanical approach was used to derive Pauling’s empirical bond valence-length relationship by considering overlap of hydrogen-like orbitals. An expression for the b “empirical” fitting parameter was derived in terms of atomic-orbital exponents. A new set of orbital exponents is presented using published atomic/covalent radii and a continuous function for the effective principal quantum. The b parameters calculated from the orbital exponents are consistent with bond …

Comparison Of Phenolic Compounds And Antioxidant Capacities Of Traditional Sorghum Beers With Other Alcoholic Beverages, Fatouma Abdoul-Latif, Romaric G. Bayili, Louis C. Obame, Mamoudou H. Dicko Prof.

Pr. Mamoudou H. DICKO, PhD

Thirty samples of sorghum beers “dolo” were selected from traditionally fermented household manufacturers from Burkina Faso. Dolo samples were screened for their total phenolic content, proanthocyanidins and putative antioxidant capacities, and were compared with industrial beers and wines. Total phenols were measured using the Folin-Ciocalteu method. Proanthocyanidins content were determined by the method of HCl-butanol hydrolysis. Antioxidant activities were evaluated both with 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and by the trolox equivalent antioxidant capacity (TEAC) using 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid radical) (ABTS•+). The average contents of total phenols and proanthocyanidins were 506 μg GAE/ml of dolo and 45 μg APE/ml of dolo, respectively. An …

Toxicity Assessment And Analgesic Activity Investigation Of Aqueous Acetone Extracts Of Sida Acuta Burn F. And Sida Cordifolia L. (Malvaceae), Medicinal Plants Of Burkina Faso, Kiessoum Konate, Adama Hilou, Raïssa Rr Aworet-Samseny, Alain Souza, Nicolas Barro, Mamoudou H. Dicko Prof., Jacques Datté, Bertrand M’Batchi

Pr. Mamoudou H. DICKO, PhD

Background Sida acuta Burn f. and Sida cordifolia L. (Malvaceae) are traditionally used in Burkina Faso to treat several ailments, mainly pains, including abdominal infections and associated diseases. Despite the extensive use of these plants in traditional health care, literature provides little information regarding their toxicity and the pharmacology. This work was therefore designed to investigate the toxicological effects of aqueous acetone extracts of Sida acuta Burn f. and Sida cordifolia L. Furthermore, their analgesic capacity was assessed, in order to assess the efficiency of the traditional use of these two medicinal plants from Burkina Faso. Method For acute toxicity …

Antibacterial Activity Against Beta- Lactamase Producing Methicillin And Ampicillin-Resistants Staphylococcus Aureus: Fractional Inhibitory Concentration Index (Fici) Determination, Kiessoun K Onate, Jacques François Mavoungou, Alexis Nicaise Lepengué, Raïssa Rr Aworet-Samseny, Adama Hilou, Mamoudou H. Dicko Prof., Bertrand M’Batchi

Pr. Mamoudou H. DICKO, PhD

The present study reports the antibacterial capacity of alkaloid compounds in combination with Methicillin and Ampicillin-resistants bacteria isolated from clinical samples. The resistance of different bacteria strains to the current antibacterial agents, their toxicity and the cost of the treatment have led to the development of natural products against the bacteria resistant infections when applied in combination with conventional antimicrobial drugs. The antibacterial assays in this study were performed by using inhibition zone diameters, MIC, MBC methods, the time-kill assay and the Fractional Inhibitory Concentration Index (FICI) determination. On the whole, fifteen Gram-positive bacterial strains (MRSA/ARSA) were used. Negative control …

Bacteriocin Formation By Dominant Aerobic Sporeformers Isolated From Traditional Maari, Donatien Kabore, Line Thorsen, Dennis Sandris Nielsen, Torben Sune Berner, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jackobsen

Pr. Mamoudou H. DICKO, PhD

The antimicrobial activity of 8 Bacillus spp. and 2 Lysinibacillus spp. representing the predominant aerobic sporeformers during traditional maari fermentations, a traditional fermented baobab seeds product fromBurkina Faso,was investigated. The antimicrobial activitywas assessed against a total of 31 indicator organisms representing various Gram-negative and positive pathogens. The screening showed that 3 Bacillus subtilis strains (B3, B122 and B222) in particular had antimicrobial activity against some Gram-positive organisms and were selected for further studies. Itwas found that the antimicrobial substances producedwere heat stable, in-sensitive to catalase, sensitive to protease and trypsin but resistant to the proteolytic action of papain and proteinase …

Acid Resistance, Bile Tolerance And Antimicrobial Properties Of Dominant Lactic Acid Bacteria Isolated From Traditional “Maari” Baobab Seeds Fermented Condiment, Donatien Kabore, Hagrétou Sawadogo-Lingani, Mamoudou H. Dicko Prof., Bréhima Diawara, Mogens Jacobsen

Pr. Mamoudou H. DICKO, PhD

Maari is a fermented food condiment obtained by spontaneous fermentation of seeds from the baobab tree (Adansonia digitata). Nine dominant lactic acid bacteria (LAB) strains, isolated from traditional maari fermentation were examined for their resistance to pH 2.5, their tolerance to 0.3% bile and their antimicrobial activities against pathogenic bacteria. The agar spot test was used to screen the dominant LAB for antagonistic activity against a total of 21 indicator organisms including Bacillus cereus strains, Salmonella spp., Listeria monocytogenes, Yersinia enterocolitica, Escherichia coli and Micrococcus luteus. It was observed that all LAB strains survived in 0.3% bile and exhibited antimicrobial …

A Review Of Baobab (Adansonia Digitata) Products: Effect Of Processing Techniques, Medicinal Properties And Uses, Donatien Kabore, Hagrétou Sawadogo-Lingani, Bréhima Diawara, Clarise Compaoré, Mamoudou H. Dicko Prof., Mogens Jacobsen

Pr. Mamoudou H. DICKO, PhD

A general literature review including the effect of processing techniques, medicinal value and uses of baobab tree is reported in this manuscript. Baobab tree has multi-purpose uses, as it produces food and non-food products such as medicines, fuel, timber, fodder. Every part of the baobab tree is reported to be useful. The seeds, leaves, roots, flowers, fruit pulp and bark of baobab are edible. Baobab leaves are used in the preparation of soup. Seeds are used as a thickening agent in soups, but they can be fermented and used as a flavouring agent or roasted and eaten as snacks. The …