ABSTRACT
Osteomyelitis is an inflammation of the bone tissue that results from an infection. Bacteria can reach the bone through the bloodstream. Predisposed individuals include immunocompromised patients, such as diabetics and HIV patients. Older age and trauma are common risk factors for osteomyelitis. We report a case of osteomyelitis where a male in his early seventies came to the Emergency Department with a right swollen finger without having any history of trauma or infection. With the patient's history, we could not find anything to explain the presenting symptoms' cause. While performing the physical exam, we noticed the patient had a colostomy bag and went in-depth on this topic. He says he cleans his colostomy bag daily with his right hand. After evaluating the patient, surgery was performed with an incision and drainage. Diagnosis was made via MRI images and wound culture results, which showed early developing osteomyelitis and anaerobic Gram-positive cocci. These bacteria are commonly found in the gastrointestinal tract. While discussing this case with infectious disease, we could not rule out that the cause of this patient's infection could be because of improper hygiene protocols while changing his colostomy bag. With this case report, we aim to raise awareness of the importance of having proper hygiene when cleaning colostomy bags, as this can alter our skin barrier and organisms can enter and establish bone infections.
ABSTRACT
A MEMS (micro-electro-mechanical systems) micropump with circular bossed membrane designed for nanoliter drug delivery is characterized in this article. A quasistatic model under consideration of low operating frequency is used to characterize this micropump. The mathematical model is an ordinary differential equation that describes the behavior of the micropump by including its key components of bossed membrane and inlet/outlet microvalves. Characterizations of bossed membrane and microvalves are carried out separately in the finite element analysis ANSYS package. The stroke volume of the membrane is calculated within the range that the linear deflection theory is valid. Analysis of the microvalve is a challenging task in microfluidics because it is a coupled field (solid-fluid coupling) problem. To solve the structural (solid) or fluid part separately is impractical in characterizing drug-delivery micropumps. Based on sequential weak solid-fluid coupling in ANSYS/FLOTRAN, the flow rates across the inlet and outlet microvalves are analyzed and simulated. Because the quasistatic equation contains several nonlinear terms, closed-form analytical solution for this equation is impossible; thus MATLAB is used to solve it numerically. The transient flow rate of the micropump is obtained by substituting the pressure in microchamber into the flow rate function of outlet microvalves. Integration of the function over 1 driving cycle and multiplication by the driving frequency provides the drug-delivery rate of the micropump.
