Comparison between cerebrospinal fluid and serum levels of myelin-associated glycoprotein, total antioxidant capacity, and 8-hydroxy-2?-deoxyguanosine in patients with multiple sclerosis

Background: Multiple sclerosis (MS) is a chronic inflammatory disease characterized by demyelinated lesions in the brain, the spinal cord, and the optic nerve. It is one of the most common neurological disorders. In this study, serum and cerebrospinal fluid (CSF) levels of total antioxidant capacity (TAC), myelin-associated glycoprotein (MAG), and 8-hydroxy-2?-deoxyguanosine (8-OHdG) were investigated to determine their effects on MS. Materials and method: In this study, 25 serum and cerebrospinal samples from MS patients as a case group and 40 serum and CSF samples from healthy participants as a control group were collected and analyzed. Concentrations of TAC, MAG, and 8-OhdG were determined in the samples using a dedicated kit and relayed using the ELISA device. Results: The mean serum antibody levels of MAG and TAC were higher in the case group than the control group, although the difference in the MAG level was not significant (P > 0.05). However, the mean serum level of ?8 OHdG was lower in the case group than the control group. Moreover, the mean levels of the evaluated biomarkers in the CSF samples were higher in the case group than in the control group. Still, the difference was only significant in terms of TAC levels (P < 0.05). Receiver operating characteristics curve analysis showed that the area under the curve was 0.71 and 0.69 for 8-OhdG and TAC serum levels, respectively, and 0.73 for both TAC and CSF levels, which was not significantly different from that in other biomarkers. Conclusion: Elevated TAC levels in serum and CSF samples and 8-OhdG in serum samples may be associated with MS pathogenesis. However, further investigation is needed to consider these cases as a follow-up to the therapeutic goals or treatment process. © 2020 Elsevier B.V

Force characterization and analysis of thin film actuators for untethered microdevices

In recent years, untethered microdevices have drawn significant attention due to their small size, weight and their ability to exert forces without the need for wires or tethers. Such microdevices are relevant to implantable biomedical devices, miniature robotics, minimally invasive surgery, and microelectromechanical systems. While devices using these actuators have been widely utilized in pick-and-place and biopsy applications, the forces exerted by these actuators have yet to be characterized and analyzed. Lack of precise force measurements and validated models impedes the clinical applicability and safety of such thin film microsurgical devices. Furthermore, present-day design of thin film microdevices for targeted applications requires an iterative trial-and-error process. In order to address these issues, we present a novel technique to measure the force output of thin film microactuators. Also, we develop and fabricate three designs of residual stress microactuators and use them to validate this technique, and establish a relationship between performance and design parameters. In particular, we find an inverse dependence of the thickness of the actuator and its force output, with 70 nm, 115 nm and 200 nm actuators exerting 7.8 μN, 4.7 μN, and 2.7 μN, respectively. Besides these findings, we anticipate that this microsystem measurement approach could be used for force measurements on alternate microactuators including shape memory, piezo and electromagnetic actuators