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Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes

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Nano-Micro Letters 2022年第2期14卷 60-78页

作者： Hyeonhee Roh Young Jun Yoon jin Soo Park dong-Hyun Kang Seung Min Kwak Byung Chul lee Maesoon Im Brain Science Institute Korea Institute of Science and Technology(KIST)Seoul 02792South Korea Division of Electrical Engineering College of EngineeringKorea UniversitySeoul 02841South Korea Micro/Nano Fabrication Center KISTSeoul 02792South Korea Division of Bio‑Medical Science&Technology KIST SchoolUniversity of Science&Technology(UST)Seoul 02792South Korea

Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine *** work presents a novel but simple method to fabricate high-density silicon(Si)microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern *** proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching(DRIE)***,a photoresist layer was patterned on a Si substrate to define areas to be etched,which will eventually determine the final location and shape of each individual ***,the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si ***,the photoresist was removed for more isotropic etching;the 2nd DRIE isolated and sharpened microneedles from the predefined trench *** on diverse photomask designs,the 2nd DRIE formed arrays of microneedles that have various height distributions,as well as diverse cross-sectional shapes across the *** these simple steps,high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm^(-2)on a Si *** tests showed a small force as low as~172μN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse *** demonstrate a feasibility of drug delivery application,we also implemented silk microneedle arrays using molding *** fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery,neuroprosthetic devices,and so on.

关键词： Microneedle Various heights Cross-sectional shapes Isotropic etch Deep reactive ion etching

Simultaneously improving strength and ductility through laminate structure design in Mg–8.0Gd–3.0Y-0.5Zr alloys

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Journal of Materials Science & Technology 2021年第12期71卷 195-200页

作者： jing Li Mengjie Zhao Li jin Fenghua Wang Shuai dong Jie dong National Engineering Research Center of Light Alloy Net Forming&State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China

The laminate structure was applied to improve the mechanical properties of Mg-8.0 Gd-3.0 Y-0.5 Zr *** types of laminate structures only with different distribution positions of fine grains were produced by friction-stir *** show that the trilayer structure sample exhibits an excellent strengthductility synergy compared to the homogenous structure and bilayer *** enhanced mechanical properties are resulted from the hetero-deformation induced(HDI)stress strengthening and strain hardening which would be enhanced by increasing the quantity of *** observations suggest a crucial role of the number of interfaces in designing the laminate structure.

关键词： Friction-stir processing Mg-Gd-Y-Zr alloy Laminate structure Interface Strength-ductility synergy

The modulation of radiation-induced cell death by genistein in K562 cells:Activation of thymidine kinase 1

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Cell Research 2004年第4期14卷 295-302页

作者： Min Ho JEONG,Young Hee jin,Eun Young KANG,Wol Soon JO,Hwan Tae PARK,Jae dong lee,Yeo jin YOO,Soo jin JEONG Research Supporting Center for Medical Science (BK21 program) dong-A University College of Medicine Busan Korea Research Supporting Center for Medical Science (BK21 program) dong-A University College of Medicine Busan Korea Research Supporting Center for Medical Science (BK21 program) dong-A University College of Medicine Busan Korea Research Supporting Center for Medical Science (BK21 program) dong-A University College of Medicine Busan Korea Research Supporting Center for Medical Science (BK21 program) dong-A University College of Medicine Busan Korea Department of Microbiology Pusan National University Busan Korea Research Supporting Center for Medical Science (BK21 program) dong-A University College of Medicine Busan Korea Research Supporting Center for Medical Science (BK21 program) dong-A University College of Medicine Busan Korea Virus Tumor Biology Section Laboratory of Cellular Oncology Center for Cancer Research National Cancer Institutes National Institute of Health Bethesda MD 20892 USA

Ionizing radiation is one of the most effective tools in cancer therapy. In a previous study, we reported that protein tyrosine kinase (PTK) inhibitors modulate the radiation responses in the human chronic myelogenous leukemia (CML) cell line K562. The receptor tyrosine kinase inhibitor, genistein, delayed radiation-induced cell death, while non-recepter tyrosine kinase inhibitor, herbimycin A (HMA) enhances radiation-induced apoptosis. In this study, we focused on the modulation of radiation-induced cell death by genistein and performed PCR-select suppression subtractive hybridization (SSH) to understand its molecular mechanism. We identified human thymidine kinase 1 (TK1), which is cell cycle regulatory gene and confirmed expression of TK1 mRNA by Northern blot analysis. Expression of TKl mRNA and TK1 enzymatic activity were parallel in their increase and decrease. TK1 is involved in G1-S phase transition of cell cycle progression. In cell cycle analysis, we showed that radiation induced G2 arrest in K

关键词： K562 radiation cell death genistein thymidine kinase 1 cell cycle.

Lightweight innovation ADIs help development of renewable energy and new technology industries in China

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China Foundry 2024年第5期21卷 507-515页

作者： Qi-dong Yan Xu-dong Gong Wen-bang Gong jin-cheng Liu ADI Committee of China Foundry Association Beijing 100000China Yuzhou Henglilai New Materials Co. Ltd.Xuchang 452570HenanChina Kunshan Changjian Foundry Industry Co.Ltd. Kunshan 215311JiangsuChina School of Mechanical Engineering and Automation Wuhan Textile UniversityWuhan 430200China WFO Ferrous Metals Commission Shenyang 110022China

The world is undergoing profound changes in energy and *** are vigorously developing new sustainable energy sources and *** energy sources encompass various technologies such as wind turbines,solar energy,nuclear energy,and ***,emerging technology fields include new energy vehicles,robots,and artificial intelligence devices,among *** renewable energy industries and implementation of new technologies necessitate the development and adoption of new equipment and *** ductile iron(ADI)is renowned for its unique microstructure and superior *** utilizing ADI,lightweight and innovative castings can be designed to not only reduce weight but also save energy and decrease *** importantly,these castings enhance the efficiency and reliability of new energy equipment and emerging technology *** paper describes the development,applications,and future prospects of lightweight and innovative ADI castings within sectors such as solar photovoltaic(PV),wind power generation,industry robots,and trucks in China.

关键词： lightweight ADI renewable energy emission reduction

Detection Technique of Software-Induced Rowhammer Attacks

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Computers, Materials & Continua 2021年第4期67卷 349-367页

作者： Minkyung lee jin Kwak ISAA Lab. Department of Computer EngineeringAjou UniversitySuwon16499Korea Department of Cyber Security Ajou UniversitySuwon16499Korea

Side-channel attacks have recently progressed into software-induced *** particular,a rowhammer attack,which exploits the characteristics of dynamic random access memory(DRAM),can quickly and continuously access the cells as the cell density of DRAM increases,thereby generating a disturbance error affecting the neighboring cells,resulting in bit *** a rowhammer attack is a highly sophisticated attack in which disturbance errors are deliberately generated into data bits,it has been reported that it can be exploited on various platforms such as mobile devices,web browsers,and virtual ***,there have been studies on bypassing the defense measures of DRAM manufacturers and the like to respond to rowhammer attacks.A rowhammer attack can control user access and compromise the integrity of sensitive data with attacks such as a privilege escalation and an alteration of the encryption *** an attempt to mitigate a rowhammer attack,various hardware-and software-based mitigation techniques are being studied,but there are limitations in that the research methods do not detect the rowhammer attack in advance,causing overhead or degradation of the system ***,in this study,a rowhammer attack detection technique is proposed by extracting common features of rowhammer attack files through a static analysis of rowhammer attack codes.

关键词： Rowhammer attack static analysis detecting technique side-channel attack bit flip

Perfluorooctanoic acid(PFOA) and perfluorooctanesulfonic acid(PFOS) concentrations in the South Korean agricultural environment: A national survey

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Journal of Integrative Agriculture 2017年第8期16卷 1841-1851页

作者： Geun-Hyoung Choi Deuk-Young lee dong-Kyu Jeong Saranya Kuppusamy Yong Bok lee Byung-Jun Park jin-Hyo Kim Chemical Safety Division National Institute of Agricultural ScienceRural Development Administration Division of Applied Life Science(BK21 Plus) Institute of Agriculture and Life Science(IALS)Gyeongsang National University

Research on the occurrence of perfluorochemicals （PFCs） such as perfluorooctanesulfonic acid （PFOS） and perfluorooctanoic acid （PFOA） in the agricultural environment is lacking, in spite of their potential risk via food chain transfer from aquatic and soil-plant systems to animals and/or humans. In the present study, for the first time, soil and water samples collected from 243 different agricultural sites adjacent to waste water treatment plants （WWTPs） belonging to 81 cities and 5 provinces with different levels of industrialization in South Korea were monitored for concentrations of PFOS and PFOA by use of solid phase extraction and liquid chromatography-tandem mass spectroscopy （LC-MS/MS）. Significant mean concentrations of PFOA （0.001-0.007 tJg L-1 water and 〈0.05-1.573 tJg kg-1 soil） and PFOS （0.001-0.22 tJg L-1 water and 〈0.05-0.741 pg kg-1 soil） were found in all samples. Concentrations of PFCs in soils were high, highlighting that soil is an important sink for PFCs in the agricultural environment. Samples from near WWTPs in Gyeongsang Province contained the highest concentrations of PFOS and PFOA, reflecting the concentration of heavy industry in the province. The concentrations of PFCs in agricultural water （most samples 〈0.05 pg L-~） and soils （most samples 〈1 IJg kg-~） from South Korea were less than acceptable guideline values, indicating that South Korea is not a hotspot of PFOS and PFOA contamination and that there is negligible risk to human and ecological health from these chemicals. However, further studies investigating the seasonal variation in PFOA, PFOS and other perfluorochemical concentrations in the agricultural environment are needed.

关键词： PFOS PFOA agricultural environment residual concentration South Korea

Optimization and Characterization of Nicosulfuron-Degrading Enzyme from Bacillus subtilis Strain YB1

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Journal of Integrative Agriculture 2012年第9期11卷 1485-1492页

作者： KANG Zhan-hai dong jin-gao ZHANG jin-lin College of Plant Protection Agricultural University of Hebei Baoding 071001 P.R China College of Life Sciences Agricultural University of Hebei Baoding 071001 P.R.China

A strain of Bacillus subtilis strain YB 1, isolated and preserved in our lab., showed a high nicosulfuron-degrading activity. Optimization of culture conditions on production of nicosulfuron-degrading enzyme from Bacillus subtilis strain YB 1 was carried out through mono-factor experiments. The characterization of degrading enzyme（s） was studied in this paper. The results showed that B. subtilis YB1 can use nicosulfuron as sole carbon source under aerobic condition. The key enzyme（s） involved in the initial biodegradation of nicosulfuron was localized to extracellular proteins and showed to be induced expressed. Enzyme-specific activity was up to 89.34 U mg-1 at pH 8.0 and 30℃, incubation for 96 h, inoculum 4.5x108 CFU mL-1 in Luria-Bertani liquid medium with nicosulfuron of 40 mg L-1. The maximum degradation rate of extracellular crude enzymes on nicosulfuron was 66% at pH 9.0, 35℃ in the enzymatic reaction system with nicosulfuron of 5 mg L-1. This degrading enzyme（s） was sensitive to high temperature, but kept high activity under alkaline conditions.

关键词： Bacillus subtilis nicosulfuron microbial degradation enzyme

Bioinspired Segment Robot with Earthworm-like Plane Locomotion

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Journal of Bionic Engineering 2016年第2期13卷 292-302页

作者： Chang-Woo Song dong-Jun lee Seung-Yop lee Department of Mechanical Engineering Sogang University 1 Shinsu-dong Mapo-gu Seoul 121-742 Republic of Korea

In this paper, a miniaturized segment robot using solenoids is developed to mimic the plane locomotion of earthworms. The bioinspired robot is composed of five segmented bodies, and one segment has two solenoid actuators. This robot can move linearly and it can also turn due to the pair of solenoid actuators that facilitate the earthworm-like peristaltic locomotion. We have designed a miniaturized solenoid with a permanent magnet plunger in order to increase the total electromagnetic force. A theoretical analysis is performed to predict the linear and turning motions of each segment, and the optimal profiles of input signals are obtained for fast locomotion. Experiments are then conducted to determine the linear and turning motions of the segment robot. It takes about 0.5 s for the five segments to complete one cycle of the peristaltic locomotion. In experiments, the segment robot is shown to have the linear and angular velocities of 27.2 mm·s^-1 （0.13 body-length per second） and 2 degrees per second, respectively.

关键词： bioinspired robot earthworm peristaltic locomotion solenoid segmented robot

Difference in extrusion temperature dependences of microstructure and mechanical properties between extruded AZ61 and AZ91 alloys

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Journal of Magnesium and Alloys 2023年第5期11卷 1683-1696页

作者： dong Hee lee Gyo Myeong lee Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

The effects of extrusion temperature on the microstructure and tensile properties of extruded AZ61 and AZ91 alloys are investigated by subjecting them to hot extrusion at 300 and 400℃.Although the average grain size of the extruded AZ61 alloy slightly increases from 9.5 to 12.6μm with increasing extrusion temperature,its resultant microstructural variation is *** contrast,the average grain size of the extruded AZ91 alloy significantly increases from 5.7 to 22.5μm with increasing extrusion temperature,and the type of Mg17Al12 precipitates formed in it changes from fine dynamic precipitates with a spherical shape to coarse static precipitates with a lamellar *** the extrusion temperature increases,the tensile yield strength of the extruded AZ61 alloy increases from 183 to 197 MPa while that of the extruded AZ91 alloy decreases from 232 to 224 *** tensile elongations of the extruded AZ61 and AZ91 alloys decrease with increasing extrusion temperature,but the degree of decrease is significant in the latter *** different extrusion temperature dependences of the tensile properties of the extruded AZ61 and AZ91 alloys are discussed in terms of their microstructural characteristics,strengthening mechanisms,and crack initiation sites.

关键词： Mg-Al-Zn alloys Extrusion temperature Precipitation Strengthening mechanism Tensile properties