Mechanical, Industrial and Manufacturing Engineering

Traditional cancer treatments like radiotherapy and chemotherapy have drawbacks and are not selective for killing only cancer cells. Nonthermal atmospheric pressure plasmas with dielectric barrier discharge (DBD) can be applied to living cells and tissues and have emerged as novel tools for localized cancer therapy. The purpose of this project is to investigate the different effects caused by an innovative miniature DBD (mDBD) plasma to A549 lung cancer cells. In this study, A549 lung cancer cells were treated with mDBD plasma to assess the changes in the size of the area of cell detachment, the viability of attached or detached cells, and cell migration. Furthermore, we investigated mDBD plasma-based therapy for localized treatment of lung cancer cells through apoptotic induction. Our results indicate that plasma treatment for 120 sec causes apoptotic cell death in 35.8% of the cell population. Additionally, we observed reduced A549 cell migration in response to mDBD plasma treatment.

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Nosocomial infections caused by opportunistic bacteria pose a major healthcare problem worldwide. Out of the many microorganisms responsible for such infections, Pseudomonas aeruginosa is a ubiquitous bacterium that accounts for 10–20% of hospital-acquired infections. These infections have mortality rates ranging from 18 to 60% and the cost of treatment ranges from $20,000 to $80,000 per infection. The formation of biofilms on medical devices and implants is responsible for the majority of those infections. Only limited progress has been made to prevent this issue in a safe and cost-effective manner. To address this problem, we propose employing jet plasma to break down and inactivate biofilms in vitro. Moreover, to improve the antimicrobial effect on the biofilm, a treatment method using a combination of jet plasma and a biocide known as chlorhexidine (CHX) digluconate was investigated. We found that complete sterilization of P. aeruginosa biofilms can be achieved after combinatorial treatment using plasma and CHX. A decrease in biofilm viability was also observed using confocal laser scanning electron microscopy (CLSM). This treatment method sterilized biofilm-contaminated surfaces in a short treatment time, indicating it to be a potential tool for the removal of biofilms present on medical devices and implants.

Representative publication

Nickel-titanium (NiTi) is an attractive alloy due to its unique functional properties for biomedical and aerospace applications. It is, however, a hard task to fabricate NiTi parts because of the high reactivity and high ductility of the alloy which results in difficulties in the processing and machining. Additive manufacturing (AM) techniques have been implemented for the direct production of complex NiTi such as lattice-based and hollow structures with the potential use in aerospace and medical applications. The critical steps toward successful manufacturing such as powder preparation, optimum laser parameters, and fabrication chamber conditions are the subjects of this research project. The microstructural characteristics and structural defects, the influencing factors on the transformation temperatures, and functional properties of NiTi are studied as the influencing factors. The mechanical properties such as hardness and wear resistance, compressive behaviors, fatigue characteristics, damping and shock absorption properties are measured. 

Representative publication

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Thin film materials, energy harvesting and storage materials and devices and manufacturing of semiconductor devices

Description: development of sensors and actuators using thin film materials, energy harvesting and storage materials and devices and manufacturing of semiconductor devices.

The lunge exercise and the step-down exercise are being often prescribed by physical therapists and athletic trainers as rehabilitation for muscle strengthening. Following knee injury and/or surgery, these exercises may produce excessive loads on the knee joint, especially at the early stage of rehabilitation. There are different lunges including the anterior lunge, the anterior/lateral lunge, the lateral lunge, the posterior/lateral lunge, the posterior lunge, the lateral rotation lunge, and the posterior/lateral rotation lunge. There are also different step-down tests including the anterior-step-down, the anterior-medial step-down, the medial step-down, the posterior/medial step-down, the posterior-step-down, the medial rotation step-down, and the posterior/medial rotation step-down tests. A review of the literature indicates that few biomechanical studies were conducted to only study the anterior and posterior lunge exercises. These few studies were also very limited. The purpose of this project is to conduct a comprehensive biomechanical analysis of all types of the lunge exercise and the step-down tests to understand their effects on the biomechanics of the lower limb to include the knee and ankle joints.

Representative publication and representative publication

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Cushions have been used on spine boards to reduce the interface pressure acting on the skin and thus prevent the formation of pressure ulcers. Several studies have focused on the determination of the normal interface pressure on the buttocks while lying on spinal boards. On the other hand, and while it has been agreed upon that the shear stresses contribute to the formation of pressure ulcers, this role has not been understood or quantified. The purpose of this project is 1) to determine and quantify experimentally the contact frictional shear stresses at the buttocks while an individual is lying on a spine board when cushions of various stiffness are used, and 2) to verify the experimental results using 3-D finite element modeling.

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