RESUMO
Mechanical property characterization of micro-scale material systems, such as free-standing films or small diameter wires (<20 µm), often requires expensive, specialized test systems. Conventional tensile test systems are usually designed for millimeter scale specimens with the force sensing capability of >1N while microdevice-based testers are intended for micro-/nano-scale specimens operating within a much smaller force range of <10 mN. This disparity leaves a technology gap in reliable and cost-effective characterization methods for specimens at the intermediate scale. In this research, we introduce the cost-effective and all-in-one tensile testing system with a built-in force sensor, self-aligning mechanisms, and loading frames. Owing to the advantages of 3D printing technologies, the ranges of force measurement (0.001-1 N) and displacement (up to tens of millimeters) of our 3D printed tensile tester can be readily tailored to suit specific material dimension and types. We have conducted a finite element simulation to identify the potential sources of the measurement error during tensile testing and addressed the dominant errors by simply modifying the dimension/design of the loading frames. As a proof-of-concept demonstration, we have characterized fine copper (Cu) wires with 10-25 µm diameters by the 3D printed tensile tester and confirmed that the measured mechanical properties match with the known values of bulk Cu. Our work shows that the proposed 3D printed tensile testing system offers a cost-efficient and easily accessible testing method for accurate mechanical characterization of specimens with cross-sectional dimensions of the order of tens of micrometers.
RESUMO
PURPOSE: This study aimed to evaluate the anti-inflammatory effect of E. campestre using the aqueous extracts, obtained from the aerial parts, on Ethylene Glycol (EG)-induced calcium oxalate kidney stone in rats. MATERIALS AND METHODS: 64 male Wistar rats were randomly divided into 8 groups. Group I was considered as negative control and received normal saline for 30 days, group II as kidney stone control received EG for 30 days, groups III to VI as prophylactic treatment received EG plus 100, 200 or 400 mg/kg extracts for 30 days and groups VI to VIII received EG as therapy from day one and 100, 200 or 400 mg/kg extract from the 15th day. On the 30thday from the start of induction, rats were euthanized. Blood was collected and the kidneys were immediately excised. Slides from each one's kidneys were prepared and stained with Hematoxylin & Eosin method. Also levels of interleukin-1 beta (IL-1?) and interleukin-6 (IL-6) were determined in rat's serum by competitive ELISA kit. RESULTS: E. campestre reduced IL-1? and IL-6 levels, showing a significant reduction for both cytokines in all prophylactic groups, especially at the dose of 400 mg/kg (P-value < .001). Moreover, IL-1? (p = .011) reduced significantly in the therapy groups in 400 mg/kg dose. Crystal count reduction was seen in all prophylactic and therapy groups in comparison with group II. CONCLUSION: These results suggest that the E. campestre extract has potent suppressive effect on pro-inflammatory cytokine production in rat. Also, E. campestre decreases crystal deposition in the kidney of the hyperoxaluric rat.
