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Bone-targeted lipoplex-loaded three-dimensional bioprinting bilayer scaffold enhanced bone regeneration

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Regenerative Biomaterials 2024年第4期3卷 138-148页

作者： Woo-Jin Kim Jeong-hyun ryu Ji Won Kim Ki-tae Kim Hye-Rim Shin Heein Yoon hyun-Mo Ryoo Young-Dan Cho Department of Molecular Genetics School of Dentistry and Dental Research InstituteSeoul National UniversitySeoul03080Republic of Korea Department of Periodontology School of Dentistry and Dental Research InstituteSeoul National University and Seoul National University Dental HospitalSeoul03080Republic of Korea

Clinical bone-morphogenetic protein 2(BMP2)treatment for bone regeneration,often resulting in complications like soft tissue inflammation and ectopic ossification due to high dosages and non-specific delivery systems,necessitates research into improved biomaterials for better BMP2 stability and *** tackle this challenge,we introduced a groundbreaking bone-targeted,lipoplex-loaded,three-dimensional bioprinted bilayer scaffold,termed the polycaprolactone-bioink-nanoparticle(PBN)scaffold,aimed at boosting bone *** encapsulated BMP2 within the fibroin nanoparticle based lipoplex(Fibroplex)and functionalized it with DSS6 for bone tissue-specific targeting.3D printing technology enables customized,porous PCL scaffolds for bone healing and soft tissue growth,with a two-step bioprinting process creating a cellular lattice structure and a bioink grid using gelatin-alginate hydrogel and DSS6-Fibroplex,shown to support effective nutrient exchange and cell growth at specific pore *** PBN scaffold is predicted through in silico analysis to exhibit biased BMP2 release between bone and soft tissue,a finding validated by in vitro osteogenic differentiation *** PBN scaffold was evaluated for critical calvarial defects,focusing on sustained BMP2 delivery,prevention of soft tissue cell infiltration and controlled fiber membrane pore size in *** PBN scaffold demonstrated a more than eight times longer BMP2 release time than that of the collagen sponge,promoting osteogenic differentiation and bone regeneration in a calvarial defect *** findings suggest that the PBN scaffold enhanced the local concentration of BMP2 in bone defects through sustained release and improved the spatial arrangement of bone formation,thereby reducing the risk of heterotopic ossification.

关键词： 3D bioprinting bone-targeting lipoplex BMP2 bone regeneration

Mo and Ta addition in NbTiZr medium entropy alloy to overcome tensile yield strength-ductility trade-off

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Journal of Materials Science & Technology 2022年第14期109卷 176-185页

作者： Muhammad Akmal hyun Woo Seong Ho Jin ryu Department of Materials Science and Engineering KAISTDaejeonYuseong-gu 34141South Korea Department of Nuclear and Quantum Engineering KAISTDaejeonYuseong-gu 34141South Korea

In this study,single-phase NbTiZr and NbTiZr(MoTa)_(0.1) medium-entropy alloys(MEAs)were investigated for their use in biomedical *** alloys were prepared by arc melting,and were then cold-rolled,annealed,and characterized in terms of phase analysis,mechanical properties,fractography,and wear *** alloys showed a single body-centered cubic phase with superior mechanical,and tribological properties compared to commercially available biomedical *** and Ta-containing MEAs showed higher tensile yield strength(1060±18 MPa)and higher tensile ductility(~20%),thus overcoming the strength-ductility trade-off with no signs of transformation-induced plasticity,twinning,or *** generalized stacking fault energy(GSFE)calculations on the{112}slip system by the first-principles calculations based on density functional theory showed that the addition of less than0.2 molar fraction of Mo and Ta lowers the GSFE *** behavior posits the increase in ductility of the alloy by facilitating slips although strength is also increased by solid solution *** wear resistance of both alloys against hardened steel surfaces was superior to that of commercial biomedical ***,we concluded that NbTiZr(MoTa)_(0.1)MEA with good tensile ductility is a potential candidate for biomedical implants.

关键词： Medium-entropy alloys Wear-resistant Biomedical implants Solid solution hardening Staking fault energy

Effects of design parameters and tension on behavior of a coil using finite element analysis

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Journal of Iron and Steel Research International 2018年第9期25卷 883-891页

作者： Kyu-tae ParkI hyun-chul Park Department of Mechanical Engineering Pohang Universityof Science and Technology Pohang Gyeongbuk 790-784Korea

During the thin strip coiling process, it is necessary to use a sleeve with a mandrel to prevent excessive deformation of the strip. Stress distribution in the sleeve and in the strip is an important factor that determines the quality of the coil. However, owing to the accumulation of high pressure, it is difficult to determine the stress distribution through experimentation. Thus, stress analysis of the strip coiling process was conducted. Finite element analysis was used to investigate the effects of the weight of the strip and the mandrel on the stress distribution and stress concentration near the starting point of the coil. The radial stress was predicted for a coil with a stacked thickness of 384 mm, which corresponds to a strip length of 1486 m, using the stress analysis model developed in a preceding research. A method was presented to reduce the weight and radial stress of a strip coil. It was found that the deformation of the sleeve can be reduced by decreasing the gap between the mandrel segments. The thickness of the sleeve can be reduced from 120 to 106 mm using the stress analysis results. Furthermore, coiling tension can be reduced by 44% compared to the existing value considering the interlayer slip of the strip coil.

关键词： Strip coiling process Structural analysis Finite element method Mandrel Coiling tension

Simple method for extracting the seasonal signals of photochemical reflectance index and normalized difference vegetation index measured using a spectral reflectance sensor

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Journal of Integrative Agriculture 2021年第7期20卷 1969-1986页

作者： Jae-hyun ryu Dohyeok OH Jaeil CHO Department of Applied Plant Science Chonnam National UniversityGwangju 61186Republic of Korea

A spectral reflectance sensor(SRS)fixed on the near-surface ground was developed to support the continuous monitoring of vegetation indices such as the normalized difference vegetation index(NDVI)and photochemical reflectance index(PRI).NDVI is useful for indicating crop growth/phenology,whereas PRI was developed for observing physiological ***,the seasonal change patterns of NDVI and PRI are two valuable pieces of information in a crop-monitoring ***,capturing the seasonal patterns is considered challenging because the vegetation index values estimated by the reflection from vegetation are often governed by meteorological conditions,such as solar irradiance and ***,unlike growth/phenology,the physiological condition has diurnal changes as well as seasonal *** study proposed a novel filtering method for extracting the seasonal signals of SRS-based NDVI and PRI in paddy rice,barley,and ***,the measurement accuracy of SRSs was compared with handheld spectrometers,and the R^(2)values between the two devices were 0.96 and 0.81 for NDVI and PRI,***,the experimental study of threshold criteria with respect to meteorological variables(i.e.,insolation,cloudiness,sunshine duration,and precipitation)was conducted,and sunshine duration was the most useful one for excluding distorted values of the vegetation *** data processing based on sunshine duration,the R^(2)values between the measured vegetation indices and the extracted seasonal signals of vegetation indices increased by approximately 0.002–0.004(NDVI)and 0.065–0.298(PRI)on the three crops,and the seasonal signals of vegetation indices became noticeably *** method will contribute to an agricultural monitoring system by identifying the seasonal changes in crop growth and physiological conditions.

关键词： photochemical reflectance index normalized difference vegetation index vegetation remote sensing spectral reflectance sensor

Endoscopic bilateral stent-in-stent placement for malignant hilar obstruction using a large cell type stent

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Hepatobiliary & Pancreatic Diseases International 2016年第6期15卷 633-639页

作者： Jin Myung Park Sang Hyub Lee Kwang hyun Chung Dong Kee Jang Ji Kon ryu Yong-tae Kim Jae Min Lee Woo hyun Paik Department of Internal Medicine and Liver Research Institute Seoul National University HospitalSeoul National University College of Medicine Department of Internal Medicine Kangwon National University HospitalKangwon National University School of Medicine Department of Internal Medicine Gyeongsang National University HospitalGyeongsang National University College of Medicine Department of Internal Medicine Inje University Ilsan Paik Hospital

BACKGROUND： Bilateral stent-in-stent （SIS） self-expandable metal stent placement is technically chghallenging for palliation of unresectable malignant hilar obstruction. In the SIS technique, the uniform large cell type biliary stent facilitates contralateral stent deployment through the mesh of the first metallic stent. This study aimed to assess the technical success and clinical effectiveness of this technique with a uniform large cell type biliary stent. METHODS： Thirty-one patients who underwentlbilateral SIS placement using a large cell type stent were reviewed retrospectively. All patients showed malignant hilarl obstruction （Bismuth types Ⅱ, Ⅲ, Ⅳ） with different etiologies. RESULTS： Sixteen （51.6%） patients were male. The mean age of the patients was 67.0±14.0 years. Most patients were diagnosed as having hilar cholangiocarcinoma （58.1%） and gallbladder cancer （29.0%）. Technical success rate was 83.9%. Success was achieved more frequently in patients without masses obstructing the biliary confluence （MOC） than those with MOC （95.2% vs 60.0%, P=0.03）. Functional success rate was 77.4%. Complications occurred in 29.0% of the patients. These tended to occur more frequently in patients with MOC （50.0% vs 19.0%, P=0.11）. Median time to recurrent biliary obstruction was 188 days and median survival was 175 days. CONCLUSIONS： The large cell type stent can be used efficiently for bilateral SIS placement in malignant hilar obstruction. However, the risk of technical failure increases in patients with MOC, and caution is needed to prevent complications for these patients.

关键词： biliary tract disease cholangiocarcinoma endoscopic biliary drainage stent insertion

Practical considerations of Si-based anodes for lithiumion battery applications

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Nano Research 2017年第12期10卷 3970-4002页

作者： Jaegeon ryu Dongki Hong hyun-Wook Lee Soojin Park Department of Energy Engineering School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republic of Korea

Using Si-based anodes in Li-ion batteries is one of the most feasible approaches to achieve high energy densities despite their disadvantages, such as low conductivity and massive volume expansion, which cause unstable solid electrolyte interphase layers with mechanical failure. The forefront in research and development to address the above challenges suggests the possibility of fully commercially viable cells using various structural and interfacial modifications. In particular, we present a discussion of each dimension of Si-based anodes in multiple controlled systems, including plain, hollow, porous, and uniquely engineered structures, which are further evaluated based on their anode performances, such as initial reversibility, capacity retention for extended cycles with its efficiency, degree of volume expansion tolerance, and rate capabilities, by several practical standards in half cells. With these practical considerations, multi-dimensional structures with uniform size distributions （micrometers, on average） are strongly desired to satisfy the rigorous requirements for widespread applications. Furthermore, we closely examined several full cells composed of Si-based multicomponent anodes coupled with suitable cathodes based on practical standards to propose future research directions for Si-based anodes to keep pace with the rapidly changing market demands for diverse energy storage systems.

关键词： silicon anode dimensional control full celllithium-ion batteries practicality

Counter-balancing effects of Si on C partitioning and stacking fault energy of austenite in 10Mn quenching and partitioning steel

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Journal of Materials Science & Technology 2022年第3期98卷 248-257页

作者： Dong Hwi Kim Jee-hyun Kang Hojun Gwon Joo hyun ryu Sung-Joon Kim Graduate Institute for Ferrous Technology Pohang University of Science and TechnologyPohang 37673Republic of Korea School of Materials Science and Engineering Institute of Materials TechnologyYeungnam UniversityGyeongsan 38541Republic of Korea POSCO Technical Research Laboratories POSCOGwangyang 57807Republic of Korea

Silicon is an essential alloying element in quenching and partitioning(Q&P)steels,because it is known to suppress carbide precipitation during partitioning step and promote carbon partitioning to stabilize *** 2 wt%Si was added to 10Mn-2Al-0.2C steel,the size and fraction of the carbides formed during partitioning became smaller than in the Si-free ***,the suppression of carbide formation promoted C partitioning into austenite as ***,austenite stability was always lower with Si under the equivalent partitioning condition because Si effectively decreased the stacking fault energy of *** partitioning progressed,the both yield and tensile strengths of the Si-added steel exceeded that of the Si-free steel with the similar ductility *** was because Si was an effective solid solution strengthener,and the austenite in the Si-added steel exhibited the appropriate stability to gradually transform into martensite throughout the *** resulting strengthening effect compensated for the softening caused by martensite ***,strain hardening rate decreased continuously throughout deformation,which resulted in high tensile strength and ductility.

关键词： Steels Q&P steel Silicon Austenite stability Tensile deformation Stacking fault energy Medium Mn steel

Adhesive ginsenoside compound K patches for cartilage tissue regeneration

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Regenerative Biomaterials 2023年第1期10卷 1442-1450页

作者： Jun-Ho Yang hyun Ho Shin Donghyeon Kim Ji hyun ryu Eun-Jung Jin Department of Biological Sciences College of Health SciencesWonkwang UniversityIksanJeonbuk 54538South Korea Department of Chemical Engineering Wonkwang UniversityIksanJeonbuk 54538South Korea Department of Carbon Convergence Engineering Wonkwang UniversityIksanJeonbuk 54538South Korea Integrated Omics Institute Wonkwang UniversityIksanJeonbuk 54538South Korea

Biomaterial-based drug delivery systems have been developed to expedite cartilage regeneration;however,challenges related to drug recovery,validation,and efficient drug delivery *** instance,compound K(CK)is a major metabolite of ginsenosides that is known to protect against joint degeneration by inhibiting the production of inflammatory cytokines and the activation of immune ***,its effects on cartilage degradation and tissue regeneration remain ***,tissue-adhesive drug delivery depots that stably adhere to cartilage defects are required for CK *** this study,CK-loaded adhesive patches were reported to seal cartilage defects and deliver CK to defect sites,preventing cartilage degradation and accelerating cartilage tissue *** patches are stable and suitable for application in surgical procedures under physiological conditions and show excellent adhesiveness to cartilage *** addition,there were no significant differences in the adhesive polymeric networks before and after CK ***-loaded hydrocaffeic acid-conjugated chitosan patches significantly inhibited the stimulation of cartilage-degrading enzymes and apoptosis in osteoarthritic cartilage by releasing CK in cartilage ***,the NFkB signaling pathway of released CK from the adhesive patches in the treatment of osteoarthritis is ***,the CK-loaded adhesive patches are expected to significantly contribute to cartilage regeneration.

关键词： ginsenoside compound K adhesive patch drug delivery hydrocaffeic acid-conjugated chitosan osteoarthritis

Contrast-enhanced ultrasound in the diagnosis of nodules in liver cirrhosis

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World Journal of Gastroenterology 2014年第13期20卷 3590-3596页

作者： tae Kyoung Kim hyun-Jung Department of Medical Imaging Toronto General HospitalUniversity of TorontoToronto ON M5G 2N2Canada

Contrast-enhanced ultrasound(CEUS)using microbubble contrast agents are useful for the diagnosis of the nodules in liver *** can be used as a problem-solving method for indeterminate nodules on computed tomography(CT)or magnetic resonance imaging(MRI)or as an initial diagnostic test for small newly detected liver *** has unique advantages over CT and MRI including no renal excretion of contrast,real-time imaging capability,and purely intravascular *** carcinoma(HCC)is characterized by arterial-phase hypervascularity and later washout(negative enhancement).Benign nodules such as regenerative nodules or dysplastic nodules are usually isoechoic or slightly hypoechoic in the arterial phase and isoechoic in the late ***,there are occasional HCC lesions with atypical enhancement including hypovascular HCC and hypervascular HCC without *** are infrequently detected during HCC surveillance and mostly show rimlike or diffuse hypervascularity followed by rapid *** are often found at HCC surveillance and are easily diagnosed by *** can be effectively used in the diagnostic work-up of small nodules detected at HCC *** is also useful to differentiate malignant and benign venous thrombosis and to guide and monitor the local ablation therapy for HCC.

关键词： Hepatocellular carcinoma Liver cirrhosis Dysplastic nodule Contrast ultrasound Imaging