본 연구에서는 호흡동조화기법의 대안으로 딥러닝 자유호흡기법에서 b-value 별 겉보기확산계수 값을 평가하고 확 산강조영상과 겉보기확산계수 지도의 해부학적 일치성을 분석하여 적절한 여기횟수 값을 알아보고자 하였다. 연구 방법은 2023년 7월부터 2024년 1월까지 간 자기공명영상 검사가 의뢰된 성인 남녀 35명을 대상으로 하였고 사용 장비는 Magnetom Skyra 3.0T(Siemens, Germany)를 이용하였다. 자유호흡기법의 비교를 위해 b-value 50, 400, 800(s/mm2)의 여기횟수를 각각 딥러닝 호흡동조화기법에서 2,3,4으로 딥러닝을 이용하지 않은 일반 자유호 흡기법에서 4,6,8으로 검사하였다. 딥러닝을 추가한 일반 자유호흡기법에서는 1,2,3 여기횟수, 2,3,4 여기횟수, 3,5,6 여기횟수, 4,6,8 여기횟수로 변화하였다. 연구 결과 딥러닝 자유호흡기법에서 간의 좌엽과 우엽, 담낭의 평균 겉보기확산계수 값은 딥러닝 호흡동조화기법과 비교하여 모두 통계적 유의성을 확인하였다. 한편 정성적 평가의 해 부학적 일치성을 분석한 결과 딥러닝 자유호흡기법의 3,5,6 여기횟수와 4,6,8 여기횟수에서 가장 높은 점수를 얻었 으며 검사 시간에서는 딥러닝 호흡동조화기법과 비교하여 약 51%, 40% 감소하였다. 따라서 간 진단에 있어 딥러닝 자유호흡기법에서 b-value 별 적절한 여기횟수 값을 이용한다면 겉보기확산계수 지도의 정확도 유지와 함께 검사 시간을 감소시킬 수 있어 임상적으로 유용한 검사가 될 것으로 사료된다.
Many risk-related issues within the realm of science education have been addressed through science-technologyrelated socioscientific issues (SSI) education. It has been established that the topics categorized as SSI are interconnected with risk-related issues. These topics emphasize numerous points of convergence with the goals of SSI education, particularly in understanding and analyzing risks, including risk assessment, risk management, and risk decision-making. Such understanding can aid in grasping the complexity of SSI based on risk-related issues and facilitate informed decision-making by structuring debates. Although there has been discourse on the need for education aimed at future survival and reflection on the responsibilities and roles of education in risk-prone societies, concepts or strategies related to actual risk responses are rarely addressed in science education and schools. Education tailored to risk-prone societies is not yet well established. This study explored the incorporation of climate change risk education into science education. A framework for climate change risk education was developed, encompassing seven elements, with corresponding definitions and examples. The researchers applied this framework to evaluate the extent to which climate change risk education is integrated into the current science curriculum of Korea. Additionally, SSI lesson scenarios related to climate change were analyzed using this risk education framework to determine the types and extent of risk education incorporated. The findings underscore the importance of teaching climate change risk education to equip students for rational decision-making.
The surface of titanium (Ti) dental implants was modified by applying a zinc (Zn)-doped titanium dioxide (TiO2) coating. Initially, the Ti surfaces were etched with NaOH, followed by a hydrolysis co-condensation using tetrabutyl titanate (TBT, Ti(OC4H9)4) and zinc nitrate hexahydrate (Zn(NO3)2 ‧ 6H2O), with ammonia water (NH3 ‧ H2O) acting as a hydroxide anion source. The morphology and chemical composition of the Zn-doped TiO2-coated Ti plates were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and scanning electron microscopy (SEM). Synthesis temperatures were carefully adjusted to produce anatase Zn-doped TiO2 nanoparticles with a bipyramidal structure and approximate sizes of 100 nm. Wettability tests and cell viability assays demonstrated the biomedical potential of these modified surfaces, which showed high biocompatibility with a survival rate of over 95 % (p < 0.05) and improved wettability. Corrosion resistance tests using potentiodynamic polarization reveal that Zn-TiO2-treated samples with an anatase crystal structure exhibited a lower corrosion current density and more noble corrosion potential compared to samples coated with a rutile structure. This method offers a scalable approach that could be adapted by the biomaterial industry to improve the functionality and longevity of various biomedical implants.
We aimed to evaluate the effectiveness of ensemble optimal interpolation (EnOI) in improving the analysis of significant wave height (SWH) within wave models using satellite-derived SWH data. Satellite observations revealed higher SWH in mid-latitude regions (30o to 60o in both hemispheres) due to stronger winds, whereas equatorial and coastal areas exhibited lower wave heights, attributed to calmer winds and land interactions. Root mean square error (RMSE) analysis of the control experiment without data assimilation revealed significant discrepancies in high-latitude areas, underscoring the need for enhanced analysis techniques. Data assimilation experiments demonstrated substantial RMSE reductions, particularly in high-latitude regions, underscoring the effectiveness of the technique in enhancing the quality of analysis fields. Sensitivity experiments with varying ensemble sizes showed modest global improvements in analysis fields with larger ensembles. Sensitivity experiments based on different decorrelation length scales demonstrated significant RMSE improvements at larger scales, particularly in the Southern Ocean and Northwest Pacific. However, some areas exhibited slight RMSE increases, suggesting the need for region-specific tuning of assimilation parameters. Reducing the observation error covariance improved analysis quality in certain regions, including the equator, but generally degraded it in others. Rescaling background error covariance (BEC) resulted in overall improvements in analysis fields, though sensitivity to regional variability persisted. These findings underscore the importance of data assimilation, parameter tuning, and BEC rescaling in enhancing the quality and reliability of wave analysis fields, emphasizing the necessity of region-specific adjustments to optimize assimilation performance. These insights are valuable for understanding ocean dynamics, improving navigation, and supporting coastal management practices.
In the mid-eastern part of the Yellow Sea, large-scale shelf ridges originated from erosion on sand-mud successions that have been presently eroded by strong tidal currents. A three-layered in situ geoacoustic model is provided down to 50 m for the subbottom sedimentary succession of a 45 m water depth using the Hamilton method. The succession is divisible into two-type units of Type-A and Type-B using high-resolution seismic profiles with a deep-drilled YSDP-104 core of 44.0 m in depth below the seafloor. Type-A unit mainly comprises sandy or gravelly sediments, whereas Type-B unit mostly consists of tidal muddy sediments with some thinner sand beds. P-wave speed values are positively compatible with the mean grain size and sediment type of the core sediments. For actual modeling, the geoacoustic property values of the models were compensated to in situ depth values below the seafloor. The detailed geoacoustic model contributes to simulating sound transmission through the sedimentary successions in erosional shelf ridges of variable geoacoustic properties distributed in shallow-water environments of the mid-eastern Yellow Sea.
Background: Stress urinary incontinence (SUI) impacts the social, physical, and psychological well-being and quality of life of the patient. Several techniques exist for its management, including transcutaneous electrical stimulation (TES). Objects: We aimed to demonstrate the effects of TES on ultrasonographic variables and quality of life in women with SUI. Methods: This prospective study recruited 21 women who had been diagnosed with grade 1 or 2 SUI between July 2018 and March 2019. The exclusion criteria were pregnancy and a history of urogenital surgery. All participants were assessed at baseline and 8 weeks after intervention initiation. The bladder neck position (BNP), length of the urethra (LU), funneling index (FI), and rhabdosphincter thickness (RT) were measured. The Incontinence-Quality of Life (I-QOL) was used to assess incontinence-specific quality of life. Statistical significance level was set at p < 0.05. Results: Twenty-one patients with SUI used TES for 8 weeks. BNP and FI significantly decreased after intervention (p < 0.05). LU, anterior and posterior RT (indicators of external sphincter hypertrophy) significantly increased post-intervention (p < 0.05). The total I-QOL score increased from 64.81 to 71.86 after the intervention (p < 0.05). Conclusion: This intervention improved BNP, LU, FI, RT, and subjective indicators such as quality of life in women with SUI. Therefore, TES can be an effective non-surgical treatment method for improving SUI symptoms and quality of life in these patients.
Background: In Taekwondo athletes, ankle sprain is the most common risk factor for injury. Repeated ankle injuries lead to weakness and imbalance of the ankle muscles, resulting in chronic ankle instability (CAI). Both the ankle and toe muscles contribute to the inversion and eversion of the foot at the subtalar joint. Therefore, it is necessary to consider the ankle and toe joint positions when measuring ankle invertor and evertor strength. Objects: This study aimed to compare the muscle strength and ratio differences of the ankle invertor and evertor muscles in both the toe and ankle positions between the CAI and uninjured sides in Taekwondo athletes. Methods: Fifteen Taekwondo athletes participated in this study. The isometric strengths of both the ankle invertor and evertor were determined in different ankle and toe positions (dorsiflexion with toe extension, dorsiflexion with toe flexion, plantarflexion with toe extension, and plantarflexion with toe flexion). Paired t-tests were used to determine the differences between the ankle invertor and evertor in strength and ratio according to toe and ankle positions between the ankle CAI side and the uninjured side. Results: The results demonstrated that ankle evertor strength significantly decreased in all ankle and toe positions on the CAI side (p < 0.05). In addition, significant differences were observed in the ratios of the ankle invertor and evertor strengths in the dorsiflexion with toe flexion, plantarflexion with toe extension, and plantarflexion with toe flexion positions (p < 0.05). Conclusion: The findings of this study suggest that athletes, trainers, and clinicians should consider ankle and toe positions when measuring invertor and evertor strength and develop ankle rehabilitation protocols for Taekwondo athletes with CAI.
Background: The peroneus longus (PL) and peroneus brevis (PB) function as the primary muscles of eversion, a movement closely associated with tibial external rotation for ankle mortise stability. Ankle motion and tibial rotation vary based on different ankle and knee positions. Objects: This study aimed to investigate the PL, PB, and biceps femoris (BF) muscle activation and eversion strength during side-lying isometric eversion exercise based on different ankle positions (neutral [N] and plantarflexion [PF]) and knee positions (90° flexion [KF] and extension [KE]). Methods: Thirty healthy adults with an Ankle Joint Functional Assessment Tool score of ≥ 22 were recruited (mean age = 24.8 ± 3.1 years). Maximal isometric eversion strength and submaximal muscle activation of the PL, PB and BF were measured during isometric eversion exercise in side-lying. A 2 × 2 repeated measures analysis of variance was performed to investigate differences in muscle activation and strength. Results: The PL and PB muscle activation showed significant main effects with the knee and ankle positions (p < 0.05); activation was greater in the KE and PF positions than in the KF and N positions. The BF muscle activation showed a significant interaction effect with knee and ankle positions, which was greater in knee extension and ankle plantarflexed (KEPF) position than in knee flexion and ankle plantarflexed (KFPF) position (p < 0.05). Eversion strength showed a significant main effect only in ankle position (p < 0.05) and was greater in the N position than in the PF position. Conclusion: The results of this study indicate that the KEPF position can be recommended to facilitate contraction of the PL and PB during side-lying eversion exercise. Furthermore, the effects of the knee-ankle positions should be considered for measuring ankle eversion strength and implementing the isometric submaximal side-lying eversion exercise.
Today, the principles of green chemistry are being fundamentally applied in the chemical industry, such as the nitrobenzene industry, which is an essential intermediate for various commercial products. Research on the application of response surface methodology (RSM) to optimize nitrobenzene synthesis was conducted using a sulfated silica (SO4/SiO2) catalyst and batch microwave reactor. The nitrobenzene synthesis process was carried out according to RSM using a central composite design (CCD) design for three independent variables, consisting of sulfuric acid concentration on the silica (%), stirring time (min), and reaction temperature (°C), and the response variable of nitrobenzene yield (%). The results showed that a three-factorial design using the response surface method could determine the optimum conditions for obtaining nitrobenzene products in a batch microwave reactor. The optimum condition for a nitrobenzene yield of 63.38 % can be obtained at a sulfuric acid concentration on the silica of 91.20 %, stirring time of 140.45 min, and reaction temperature of 58.14 °C. From the 20 experiments conducted, the SO4/SiO2 catalyst showed a selectivity of 100 %, which means that this solid acid catalyst can potentially work well in converting benzene to nitrobenzene.
많은 연구에 따르면 Tenebrio molitor은 유충 단계에서 플라스틱을 섭취할 수 있다고 보고되었다. 이 연구의 목적은 T. molitor 유충의 성장과 발달에 발포폴리스티렌 섭취가 미치는 영향을 조사하는 것이다. 밀기울을 섭취한 유충의 성장률은 발포폴리스티렌을 섭취한 유충의 성장률보다 더 좋았고(p < 0.001) 발포폴리스티렌을 섭취한 유 충의 번데기로 전환되는 기간은 밀기울을 섭취한 유충의 번데기로 전환되는 기간보다 더 빨랐다(p < 0.001). 하지만 두 처리구간 생존율은 유의미한 차이가 없었다(p = 0.786). 이 결과에 따르면 발포폴리스티렌을 섭취한 유충은 체중 감소와 짧은 발육기간이 특징이지만 생존하는 것에는 문제가 없었다. 따라서 우리는 T. molitor가 플라스틱 폐기물 의 지속 가능하고 친환경적인 제거를 위한 주요 자원이라는 결론을 내렸다.
In the present study, a coal-based pitch containing 12.1% quinoline insoluble (QI) underwent isothermal heat treatment, and changes in the mesophase microstructure were analyzed for the heat treatment duration. The nuclei creation and growth rate of mesophase were affected by the distribution of QI particles in the pitch. The growth process could be explained in four regions through the mesophase area fraction. During the carbonization of carbon blocks, mesophase formation was induced in the binder phase. The physical properties of carbon blocks were measured as a function of residence time. As residence time increased, bulk density decreased and porosity increased, but electrical conductivity increased. It was determined that forming a mesophase in the binder phase during carbonization reduced the size of large pores in carbon block and improved the connectivity between particles, thereby increasing electrical conductivity. These results are expected to show greater improvement in electrical properties after graphitization.
One of the key challenges for the commercialization of carbon nanotube fibers (CNTFs) is their large-scale economic production. Among CNTF spinning methods, surfactant-based wet spinning is one of the promising techniques for mass producing CNTFs. Here, we investigated how the coagulation bath composition affects the spinnability and the properties of CNTFs in surfactant-based wet spinning. We used acetone, DMAc, ethanol, and IPA as coagulants and analyzed the relationship between coagulation bath composition and the properties of CNTFs in terms of kinetic and thermodynamic coagulation parameters. From a kinetic perspective, we found that a low mass transfer rate difference (MTRD) is favorable for wet spinning. Based on this finding, we mixed the coagulant bath with solvent in a proper ratio to reduce the MTRD, which generally improved the wet spinning. We also showed that the coagulation strength, a thermodynamic parameter, should be considered. We believe that our research can contribute to establishment of surfactant-based wet spinning of CNTFs.
With the wide application of portable wearable devices, a variety of electronic energy storage devices, including microsupercapacitors (MSCs), have attracted wide attention. Laser-induced graphene (LIG) is widely used as electrode material for MSCs because of its large porosity and specific surface area. To further improve the performance of MSCs, it is an effective way to increase the specific surface area and the number of internal active sites of laser-induced graphene electrode materials. In this paper, N-doped polyimide/polyvinyl alcohol (PVA) as precursor was used to achieve in situ doping of nitrogen atoms in laser-induced graphene by laser irradiation. Through the addition of N atoms, nitrogen-doped laser-induced threedimensional porous graphene (N-LIG) exhibits large specific surface area, many active sites, and good wettability all of which are favorable conditions for enhancing the capacitive properties of laser-induced graphene. After assembly with PVA/H2SO4 as gel electrolyte, the high surface capacitance of the MSC device with N-LIG as electrode material is 16.57 mF cm− 2 at the scanning rate of 5 mV s− 1, which is much higher than the 2.89 mF cm− 2 of the MSC device with LIG as electrode material. In addition, MSC devices with N-LIG as electrode materials have shown excellent cyclic stability and flexibility in practical tests, so they have a high application prospect in the field of flexible wearable microelectronics.
This study comprehensively investigates three types of graphite materials as potential anodes for potassium-ion batteries. Natural graphite, artificial carbon-coated graphite, and mesocarbon microbeads (MCMB) are examined for their structural characteristics and electrochemical performances. Structural analyses, including HRTEM, XRD, Raman spectroscopy, and laser particle size measurements, reveal distinct features in each graphite type. XRD spectra confirm that all graphites are composed of pure carbon, with high crystallinity and varying crystal sizes. Raman spectroscopy indicates differences in disorder levels, with artificial carbon-coated graphite exhibiting the highest disorder, attributed to its outer carbon coating. Ex-situ Raman and HRTEM techniques on the electrodes reveal their distinct electrochemical behaviors. MCMB stands out with superior stability and capacity retention during prolonged cycling, attributed to its unique spherical particle structure facilitating potassium-ion diffusion. The study suggests that MCMB holds promise for potassium-ion full batteries. In addition, artificial carbon-coated graphite, despite challenges in hindering potassium-ion diffusion, may find applications in commercial potassium-ion battery anodes with suitable coatings. The research contributes valuable insights into potassiumion battery anode materials, offering a significant extension to the current understanding of graphite-based electrode performance.