Effect of oxygen plasma treatment on adhesion improvement of Au deposited on Pa-c substrate

Jeong Hoon Lee,Tae Song Kim,Jin Wook Seong,Ki Hyun Yoon,Kyo Seon Hwang,Saeyoung Ahn 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.52

Adhesion of gold on parylene C (Pa-c) is a major hurdle in achieving reliable and durable performance for biosensor application due to the hydrophobicity of Pa-c. It is, therefore, imperative to put eorts to improve adhesion between Au and Pa-c. In this reseach, oxygen plasma treatment for adhesion improvement was performed on Pa-c surfaces at various plasma powers and times. To analyze the relation of surface energy and roughness to adhesion promotion, we used several techniques such as contact-angle, surface-energy, surface-roughness, and adhesion analyses. As the oxygen plasma power and time were increased, the surface roughness of Pa-c increased. Also, Au lms had larger and more uniform grain sizes as the oxygen plasma power and time were increased. Untreated surfaces revealed a contact angle of 108, but the contact angle drastically decreased in the initial stage of oxygen plasma treatment and slowly decreased with increasing power and time to values of 27.3 and 34, respectively. From the adhesion analysis, adhesion was improved as the plasma power or time was increased. The improvement of adhesion is related to an increase in roughness as well as carbonyl groups.

Improved resistive switching characteristics by O2 plasma treatment in bi-layer Ti/ZnO/OPT-ZnO/ITO RRAM

Jeong Hyeyeon,Shin Jeongmin,Kim Saeyoung,Pak James J. 한국물리학회 2023 Current Applied Physics Vol.49 No.-

This paper presents the effect of oxygen plasma process to the ZnO switching layer of Ti/ZnO/ITO resistive random access memory (RRAM). ZnO thin film was formed by spin-coating of the precursor solution and oxygen plasma process was carried out in three different cases: Case 1) Single ZnO film with no oxygen plasma treatment; Case 2) Single ZnO film with oxygen plasma treatment on the top; Case 3) Two ZnO layers and oxygen plasma treatment on the bottom layer. The best resistive switching characteristics were obtained from the case 3) with stable endurance over 1000 DC cycles and stable retention up to 104 s, while the case 2) showed better endurance cycle (~350 cycles) than that (<100) of the case 1). This result may be attributed to the prevention of oxygen ion absorption of Ti layer. XPS analysis indicates that the oxygen plasma process increases the oxygen contents in ZnO film, increasing metal-oxygen bonds and reducing the oxygen vacancies.

Transplantation of Differentiated Tonsil-Derived Mesenchymal Stem Cells Ameliorates Murine Duchenne Muscular Dystrophy via Autophagy Activation

Park Saeyoung,Jeong Soyeon,Nam Yu Hwa,Yum Yoonji,Jung Sung-Chul 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.6

BACKGROUND: Skeletal muscles play many important roles in the human body and any malfunction or disorder of the skeletal muscles can lead to a reduced quality of life. Some skeletal dysfunctions are acquired, such as sarcopenia but others are congenital. Duchenne muscular dystrophy (DMD) is one of the most common forms of hereditary muscular dystrophy and is caused by a deficiency of the protein, Dystrophin. Currently, there is no clear treatment for DMD, there are only methods that can alleviate the symptoms of the disease. Mesenchymal stem cells, including tonsil-derived mesenchymal stem cells (TMSCs) have been shown to differentiate into skeletal muscle cells (TMSC-myocyte) and can be one of the resources for the treatment of DMD. Skeletal muscle cell characteristics of TMSC-myocytes have been confirmed through changes in morphology and expression of skeletal muscle markers such as Myogenin, Myf6, and MYH families after differentiation. MEOTHDS: Based on these characteristics, TMSC-myocytes have been transplanted into mdx mice, a mouse model of DMD, to investigate whether they can help improve the symptoms of DMD. The red fluorescent protein gene was transduced into TMSC (TMSC-R) for tracking transplanted cells. RESULTS: Prior to transplantation (TP), it was confirmed whether TMSC-R-myocytes had the same differentiation potential as TMSC-myocytes. Increased expression of dystrophin and autophagy markers in the TP group compared with the sham group was confirmed in the gastrocnemius muscle 12 weeks after TP. CONCLUSION: These results demonstrate muscle regeneration and functional recovery of mdx via autophagy activation following TMSC-myocyte TP.

Dexamethasone treatment for bilateral lingual nerve injury following orotracheal intubation

Kim, Saeyoung,Chung, Seung-Yeon,Youn, Si-Jeong,Jeon, Younghoon The Korean Dental Society of Anesthsiology 2018 Journal of Dental Anesthesia and Pain Medicine Vol.18 No.2

Lingual nerve injury is a rare complication of general anesthesia. The causes of lingual nerve injury following general anesthesia are multifactorial; possible mechanisms may include difficult laryngoscopy, prolonged anterior mandibular displacement, improper placement of the oropharyngeal airway, macroglossia and tongue compression. In this report, we have described a case of bilateral lingual nerve injury that was associated with orotracheal intubation for open reduction and internal fixation of the left distal radius fracture in a 61-year-old woman. In this case, early treatment with dexamethasone effectively aided the recovery of the injured lingual nerve.

Characterization of Platinum Electrode Using UnBalanced Magnetic Field Sputter for Implantable Biomedical Applications

Hoon Lee,Saeyoung Ahn,Changwon Lee,Hongbae Kim,Jein Jeong,Taigun Im 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.52

Platinum (Pt) is a biocompatible material which exhibits strong thermal and electrical conductivity due to its high melting point and good durability. Thus, it is used commonly in bio-electrodes and bio-chips. In this study, a tungsten (W) wire was coated with a platinum lm and was analyzed for its mechanical and biocompatibility properties. The platinum lm was deposited by magnetron sputtering with an UnBalanced Magnetic (UBM) eld system. The experiment was performed under a variety of conditions by changing the deposition temperature, the bias voltage, the magnetic eld and the deposition time in order to deduce the optimum conditions. We examined the exfoliation and the sedimentation states of the anode and the cathode by using microscope and an electron probe microanalysis (EPMA) for the electro-chemical corrosion test using the Hank's solution. The lm showed a very low impurity level, and the surface and the cross section of the lm appeared elaborate. No sedimentation appeared in the lm, and the crystallization in the (110), the (200), the (220) and the (222) directions observed. However, at a high current density (800 mA/cm2), sedimentation was observed in the corrosion test.

Color Quantization to Visualize Perceptually Dominant Colors of an Image

JiYoung Seok(석지영),SaeYoung Rho(노세영),EunJin Kim(김은진),ByungSeok Min(민병석),Hyeon-Jeong Suk(석현정) 한국색채학회 2015 한국색채학회 논문집 Vol.29 No.2

본 연구는 이미지를 대표하는 색을 시각화하고 대표색의 적합성을 판별하기 위한 방법으로서 이미지 양자화(Quantization) 기법을 제시하고, 이를 기존에 널리 활용되던 직사각형 형태의 색채견본 방식과 비교하여 양자화 기법이 가지는 특성과 장점을 살펴보고자 하였다. 이를 위해 다섯 개 명화의 대표색을 추출한 후, 색채 견본 방식과 양자화 방식으로 대표색들을 제시하여 사용자 대상 평가를 진행하였다. 대표색 추출에는 K-평균 군집화 기법이 활용되었으며, 각 명화 이미지에 대해 3,6,9,12,15개의 대표색을 추출하여 대표색의 개수에 따른 영향 또한 보고자 하였다. 30명의 디자인 전공자들을 대상으로 대표성의 적합도를 평가하게 한 결과, 양자화 기법으로 제시된 대표색 팔레트의 적합도 점수가 훨씬 넓은 분포를 가지고 있는 것을 확인할 수 있었다. 이를 통해 양자화 기법이 대표색의 적합성에 대해 더 분별력 높은 평가 결과를 가져다줌을 알 수 있었다. 또한 일정 개수 이하의 대표색에서는 색채견본 방식이 양자화 기법보다 적합도 점수가 높은 반면, 대표색 개수가 일정이상 증가하면 양자화 기법의 적합도 점수가 더 높아지는 경향성을 통해, 추출하고자 하는 대표색이 적을수록 위치 및 면적 정보가 포함되지 않은 색채견본 방식이 더 적합함을 알 수 있었다. As an alternative technique to the conventional color swatch, we adopted color quantization to present perceptually dominant colors of an image. We facilitated five digitalized paintings and extracted the color scheme of each based on their RGB values. We adopted K-means clustering analysis and created clusters with 3, 6, 9, 12, and 15 colors. The extracted colors were presented in a color swatch format as well as color quantization. Thirty design majoring students assessed each format with regard to how properly the color set represents the original image. The results showed that the judgments varied more largely when the colors were presented as color quantization than as a color swatch. In particular, an intersection point always existed, implying that a color swatch without any semantic hints is more meaningful when a color palette contains a small number.

Structural insights into the psychrophilic germinal protease PaGPR and its autoinhibitory loop

Chang Woo Lee,Saeyoung Lee,Chang-Sook Jeong,Jisub Hwang,Jeong Ho Chang,In-Geol Choi,T. Doohun Kim,HaJeung Park,Hye-Yeon Kim,Jun Hyuck Lee 한국미생물학회 2020 The journal of microbiology Vol.58 No.9

In spore forming microbes, germination protease (GPR) plays a key role in the initiation of the germination process. A critical step during germination is the degradation of small acidsoluble proteins (SASPs), which protect spore DNA from external stresses (UV, heat, low temperature, etc.). Inactive zymogen GPR can be activated by autoprocessing of the N-terminal pro-sequence domain. Activated GPR initiates the degradation of SASPs; however, the detailed mechanisms underlying the activation, catalysis, regulation, and substrate recognition of GPR remain elusive. In this study, we determined the crystal structure of GPR from Paenisporosarcina sp. TG-20 (PaGPR) in its inactive form at a resolution of 2.5 Å. Structural analysis showed that the active site of PaGPR is sterically occluded by an inhibitory loop region (residues 202–216). The N-terminal region interacts directly with the self-inhibitory loop region, suggesting that the removal of the N-terminal pro-sequence induces conformational changes, which lead to the release of the self-inhibitory loop region from the active site. In addition, comparative sequence and structural analyses revealed that PaGPR contains two highly conserved Asp residues (D123 and D182) in the active site, similar to the putative aspartic acid protease GPR from Bacillus megaterium. The catalytic domain structure of PaGPR also shares similarities with the sequentially non-homologous proteins HycI and HybD. HycI and HybD are metalloproteases that also contain two Asp (or Glu) residues in their active site, playing a role in metal binding. In summary, our results provide useful insights into the activation process of PaGPR and its active conformation.

Immunogenicity of COVID-19 Vaccination in Patients With End-Stage Renal Disease Undergoing Maintenance Hemodialysis: The Efficacy of a Mix-and-Match Strategy

Joon-Sung Park,Dohsik Minn,Susie Hong,Saeyoung Jeong,Soohyun Kim,Chang Hwa Lee,Bongyoung Kim 대한의학회 2022 Journal of Korean medical science Vol.37 No.23

Background: The objective of this study was to evaluate the immunogenicity of coronavirus disease 2019 (COVID-19) vaccination in patients with end-stage renal disease (ESRD) on hemodialysis. Methods: ESRD patients at the hemodialysis center of a tertiary-care university-affiliated hospital and healthy employees at the clinical laboratory center were prospectively recruited between March and June 2021. For severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) antibody analysis, blood samples were collected serially on days 0, 14, 28, and 56 after the first vaccine dose, and on days 7 and 50 after the second dose. Antibodies against the SARS-CoV-2 spike protein were quantified, and SARS-CoV-2 neutralizing antibodies were measured in the serum and plasma. Results: Thirty-one ESRD patients and 55 healthy employees were regularly monitored. Twenty-five (80.6%) ESRD patients on hemodialysis received a mix-and-match strategy with ChAdOx1-BNT162b2 (AZ–Pf group) and six (19.4%) received two doses of ChAdOx1 (AZ–AZ group). ESRD patients on hemodialysis showed lower binding antibody titers and neutralizing antibody activities compared to healthy participants following the first vaccination with ChAdOx1. After the second dose, AZ-Pf group had higher immunogenicity than healthy people on days 7 and 50. The binding antibody titer and neutralizing antibody activities on days 7 and 50 were significantly higher in the AZ–Pf group than in the AZ–AZ group. Conclusion: ESRD patients on hemodialysis receiving the mix-and-match strategy (ChAdOx1–BNT162b2) have COVID-19 vaccine immunogenicity comparable to healthy individuals receiving two doses of ChAdOx1.