Recently, various types of pedicle screws have been developed considering the anatomical structure of the spine. The purpose of this study was to evaluate the pullout stiffness and strength of two types of commercial pedicle screws. The design of two type screws were single pitched thread (ST) pedicle screw and dual pitched thread (DT) pedicle screw, respectively. The tests were conducted in accordance with the ASTM standards using polyurethane (PU) test blocks which has anatomical structure of the spine. There was no significant difference in pullout stiffness between two types of screw. However, DT exhibited higher pullout strength than ST (p<0.05). Pedicle screw with dual pitched thread showed higher pullout strength without decrease in pullout stiffness compared to the standard pedicle screw. In conclusion, dual pitched thread design of the pedicle screw is considered to be more suitable than the single pitched thread for the anatomical structure of the spine.

In the case of domestic medical device advertisements, it is possible to proceed with the advertisement after medical device certification, and pre-deliberation is possible based on the medical device technical document. However, there are some medical device advertisements that stakeholders in administrative procedures have no choice but to misunderstand in customs and laws that do not consider users. In addition, medical equipment and the pre-deliberation system were judged to be unconstitutional, and unconstitutional decisions were made in accordance with the principle of prohibiting pre-censorship based on the Constitution. This is because in domestic medical device advertisements, structural contradictions and user damage occur in the central structure of each stakeholder. It is necessary to reestablish stakeholder relationships, increase water solubility from customs and laws, and seek new policy proposals. In this study, we reestablish relationships with stakeholders by applying the Autopoiesis theory, and present the grounds and directions that can prevent hype and misidentified advertisements through the establishment of user-centered policies, and the measures to be taken by the Constitutional Court unconstitutional decision.

Vibration is a mechanical cue that can be applied to adipose tissues for the purpose of treating obesity. However, the exact correlation between vibration and other anti-adipogenic pathways, such as development of cytoskeleton and apoptosis, remains unknown. The objective of this study was to investigate the unknown anti-adipogenic effects of vibration with varied frequencies on preadipocytes. 3T3-L1 preadipocytes were cultured in Dulbecco's modified Eagle's medium (DMEM) containing 5% calf serum at 37 ℃ with 5% CO2 in a humidified incubator. Vibration was generated using Arduino Uno microcontroller and vibration motor module with 1 V DC, and applied to preadipocytes for 3 days. Frequency conditions were set to 20, 55, and 90 Hz. Then, the expressions of p38 pathway, ROCK-1, α-actinin, Bax, Bcl-2, caspase-9, 8, and 3 were analyzed with western blot. As a result, p38 pathway was inhibited in 55 and 90 Hz while ROCK-1 and α-actinin were expressed in 20 Hz. Caspase-3, a terminal apoptotic factor, was activated in 20 Hz via extrinsic pathway rather than intrinsic pathway. Results suggest that various frequencies of vibration can inhibit adipogenesis via different pathways which sheds light on future mechanotransduction applications of vibration for the treatment of obesity.

Objective: The aim of this study is to consider the effect of skin tissue necrosis by improving blood flow in animal skin models for low frequency pulsed electromagnetic fields (LF_PEMF) stimulation. Methods: Twenty rats (Wistar EPM-1 male, 280-320 g) were randomly divided into control groups (n=10) and the PEMF groups (n=10). To induce necrosis of the skin tissue, skin flap was treated in the back of the rat, followed by isolation film and skin flap suturing. Subsequently, the degree of necrosis of the skin tissue was observed for 7 days. The control group did not perform any stimulation after the procedure. For the PEMF group, LF_PEMF (1 Hz, 10 mT) was stimulated in the skin flap area, for 30 minutes a day and 7 days. Cross-polarization images were acquired at the site and skin tissue necrosis patterns were analyzed. Results: In the control group, skin tissue necrosis progressed rapidly over time. In the PEMF group, skin tissue necrosis was slower than the control group. In particular, no further skin tissue necrosis progress on the day 6. Over time, a statistically significant difference from the continuous necrosis progression pattern in the control group was identified (p<0.05). Conclusions: It was confirmed that low frequency pulsed electromagnetic fields (LF_PEMF) stimulation can induce relaxation of skin tissue necrosis.