Alternative Pedicle Screw Design via Biomechanical Evaluation

With the recent increase in the elderly population, many people suffer from spinal diseases, and, accordingly, spinal fusion surgery using pedicle screws has been widely applied to treat them. However, most research on pedicle screw design has been focused on the test results rather than the behavior of the screws and vertebrae. In this study, a design platform with a series of biomechanical tests and analyses were presented for pedicle screw improvement and evaluation. The platform was then applied to an alternative hybrid screw design with quadruple and double threads. An experimental apparatus was developed to investigate the bending strength of the screw, and several tests were performed based on the ASTM F1717 standard. In the experiments, it was confirmed that the alternative pedicle screw has the highest bending strength. To examine the stress distribution of pedicle screws, finite element models were established, through which it was found that the proposed pedicle screw has sufficient mechanical safety to make it acceptable for spinal fusion treatment. Finally, we conclude that the platform has good potential for the design and evaluation of pedicle screws, and the alternative dual screw design is one of the best options for spinal fusion surgery

Development of Novel Platform to Predict the Mechanical Damage of a Miniature Mobile Haptic Actuator

Impact characterization of a linear resonant actuator (LRA) is studied experimentally by a newly-developed drop tester, which can control various experimental uncertainties, such as rotational moment, air resistance, secondary impact, and so on. The feasibility of this test apparatus was verified by a comparison with a free fall test. By utilizing a high-speed camera and measuring the vibrational displacement of the spring material, the impact behavior was captured and the damping ratio of the system was defined. Based on the above processes, a finite element model was established and the experimental and analytical results were successfully correlated. Finally, the damage of the system from impact loading can be expected by the developed model and, as a result, this research can improve the impact reliability of the LRA

Big Data Strategy for Baby Boom Generation Research

Ⅰ. 연구 개요 1. 연구 배경 2. 연구 방법 Ⅱ. 빅데이터 활용 전략 1. 빅데이터 시대의 통계청의 역할 2. 빅데이터에 대한 관점 정립 3. 해외의 공공 빅데이터(행정자료) 활용 주요 연구 사례 Ⅲ. 베이비붐 세대 연구와 빅데이터 1. 새로운 은퇴 세대: 베이비붐 세대 2. 기존 연구 개관과 빅데이터 활용의 필요성 3. 베이비붐 세대 연구를 위한 빅데이터 활용 전략 Ⅳ. 베이비붐 세대 연구의 주요 문제 1. 베이비붐 세대의 가치관과 정책에 대한 태도는 이전과 어떻게 다른가? 2. 부동산 가격의 변동은 베이비붐 세대에게 어떤 경제적⋅비경제적 영향을 미칠 것인가? 3. 최저임금 인상은 베이비붐 세대에 어떤 영향을 미치는가? 4. 노인기준연령 상향은 어떤 효과를 가져올 것인가? 5. 베이비붐 세대가 은퇴하는 일자리는 누구에게 돌아갈 것인가? 6. 증거기반정책(Evidence-Based Policy) 지원을 위한 빅데이터 활용 부

Characteristics of Occupational Exposure to Benzene during Turnaround in the Petrochemical Industries

Objectives: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process.Methods: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1hr) samples were taken during TAs. TA was classified into three stages: shut-down, maintenance and start-up. All works were classified into 12 occupation categories.Results: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1ppm) and the short-term exposure limit (STEL-OEL, 5ppm) were 4.1% (20 samples of 488) and 6.0% (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05).Conclusion: These findings suggest that the periodic work environment must be assessed during non-routine works such as TA

Constitutive Oxidative Stress by SEPHS1 Deficiency Induces Endothelial Cell Dysfunction

The primary function of selenophosphate synthetase (SEPHS) is to catalyze the synthesis of selenophosphate that serves as a selenium donor during selenocysteine synthesis. In eukaryotes, there are two isoforms of SEPHS (SEPHS1 and SEPHS2). Between these two isoforms, only SEPHS2 is known to contain selenophosphate synthesis activity. To examine the function of SEPHS1 in endothelial cells, we introduced targeted null mutations to the gene for SEPHS1, Sephs1, in cultured mouse 2H11 endothelial cells. SEPHS1 deficiency in 2H11 cells resulted in the accumulation of superoxide and lipid peroxide, and reduction in nitric oxide. Superoxide accumulation in Sephs1-knockout 2H11 cells is due to the induction of xanthine oxidase and NADPH oxidase activity, and due to the decrease in superoxide dismutase 1 (SOD1) and 3 (SOD3). Superoxide accumulation in 2H11 cells also led to the inhibition of cell proliferation and angiogenic tube formation. Sephs1-knockout cells were arrested at G2/M phase and showed increased gamma H2AX foci. Angiogenic dysfunction in Sephs1-knockout cells is mediated by a reduction in nitric oxide and an increase in ROS. This study shows for the first time that superoxide was accumulated by SEPHS1 deficiency, leading to cell dysfunction through DNA damage and inhibition of cell proliferation

Hypothalamic GABRA5-positive neurons control obesity via astrocytic GABA

The lateral hypothalamic area (LHA) regulates food intake and energy balance. Although LHA neurons innervate adipose tissues, the identity of neurons that regulate fat is undefined. Here we show that GABRA5-positive neurons in LHA (GABRA5LHA) polysynaptically project to brown and white adipose tissues in the periphery. GABRA5LHA are a distinct subpopulation of GABAergic neurons and show decreased pacemaker firing in diet-induced obesity mouse models in males. Chemogenetic inhibition of GABRA5LHA suppresses fat thermogenesis and increases weight gain, whereas gene silencing of GABRA5 in LHA decreases weight gain. In the diet-induced obesity mouse model, GABRA5LHA are tonically inhibited by nearby reactive astrocytes releasing GABA, which is synthesized by monoamine oxidase B (Maob). Gene silencing of astrocytic Maob in LHA facilitates fat thermogenesis and reduces weight gain significantly without affecting food intake, which is recapitulated by administration of a Maob inhibitor, KDS2010. We propose that firing of GABRA5LHA suppresses fat accumulation and selective inhibition of astrocytic GABA is a molecular target for treating obesity. © 2023, The Author(s), under exclusive licence to Springer Nature Limited.11Nsciescopu