Intercalation of conjugated polyelectrolytes in layered titanate nanosheets for enhancement in photocatalytic activity

Hong, Seong Won,Kim, Aran,Choi, Joon Hyun,Jung, Hyun,Park, Jin Kuen Elsevier 2019 Journal of solid state chemistry Vol.269 No.-

<P><B>Abstract</B></P> <P>Cationic π-conjugated polyelectrolytes (CPEs) were successfully intercalated into layered titanate (TiO<SUB>2</SUB>), while exfoliated layered titanates were reassembled into lamellar structures. The resulting composites showed significantly enhanced visible light absorbance and enhanced photocatalytic activity with respect to layered titanate, which was proven by the photodegradation of methylene blue in aqueous media under irradiation by visible light. Notably, some amount of tetrabutylammonium (TBA) used for the delamination of a layered titanate could be co-intercalated with CPEs, and the residual TBA could be removed via continuously repeating the intercalation process, maintaining the spatial arrangement and content of CPEs in the confined area of layered titanates. However, with the presence of TBA, the hybrid demonstrated greater performance in the photodegradation of methylene blue at any given period of time and almost complete degradation of such dye within 8 min. The significant difference in photocatalytic efficiency with or without TBA suggested that the TBA effectively reduced the surface energy at the interface between the organic components and aqueous medium, which was evidenced by the dispersity assessment of hybrids with or without TBA.</P> <P><B>Graphical abstract</B></P> <P>Cationic π-conjugated polyelectrolytes (CPEs) were successfully intercalated into layered titanate (TiO<SUB>2</SUB>). The resulting composites showed significantly enhanced photocatalytic activity which was proven by the photodegradation of methylene blue in aqueous media under irradiation by visible light. Notably, with the presence of TBA, the hybrid demonstrated greater performance in the photodegradation of methylene blue at any given period of time and almost complete degradation of such dye within 8 min.</P> <P>[DISPLAY OMISSION]</P>

Effect of TiO2 nanotubes arrays on osseointegration of orthodontic miniscrew.

Jang, Insan,Shim, Seong-Cheol,Choi, Dong-Soon,Cha, Bong-Kuen,Lee, Jae-Kwan,Choe, Byung-Hak,Choi, Won-Youl Kluwer Academic Publishers 2015 BIOMEDICAL MICRODEVICES Vol.17 No.4

<P>To increase the stability of orthodontic miniscrews, TiO2 nanotube arrays were fabricated on the surface of Ti miniscrews and the effect of those arrays on the osseointegration of miniscrews was evaluated. Highly ordered TiO2 nanotube arrays were grown on the surface of orthodontic miniscrews. Ethylene glycol based electrolyte was used in the anodic oxidation process. Two-step anodic oxidation was conducted to obtain clean and open windows in TiO2 nanotube arrays. The diameter and length of the TiO2 nanotube arrays were ~ 70 nm and ~ 5 μm, respectively. The miniscrews with TiO2 nanotube arrays were implanted in the legs of New Zealand white rabbits for 8 weeks. Histological osseointegration was assessed by bone-to-implant contact ratio, and three-dimensional bone volume ratio was measured by micro-computed tomography analysis. The miniscrews with TiO2 nanotube arrays had a greater mean bone-to-implant contact ratio of 52.8 % than the control, 29.3 %. Mean bone volume ratio (BV/TV) was also higher in the miniscrews with TiO2 nanotube arrays, at 81.2 % than those in the control via micro-CT analysis. Our findings support that TiO2 nanotube arrays on the surface of miniscrews enhance osseointegration and improve the stability of the miniscrew.</P>

밴쿠버 분류 B2와 B3 삽입물 주위 골절을 위한 대퇴 스템 재치환술

성윤재(Yoon Jae Seong),신원철(Won Chul Shin),조형준(Hyung Joon Cho),이정섭(Jung Sub Lee),서근택(Kuen Tak Suh) 대한정형외과학회 2013 대한정형외과학회지 Vol.48 No.3

목적: 밴쿠버 분류 B2와 B3 대퇴 스템 주위 골절 치료 시 대퇴 스템 재치환술의 결과를 분석하였다. 대상 및 방법: 1997년 5월부터 2009년 9월까지 인공고관절 치환술 후 발생한 대퇴 스템 주위의 불안정 골절을 수상한 15예를 대상으로 하였다. 밴쿠버 분류에 의해 B2는 11예, B3는 4예였다. 밴쿠버 B3는 B2의 치료와 동일하게 관혈적 정복과 긴 대퇴 스템 재치환 및 동종 망상골을 이식하였다. 추가적인 안정성이 필요한 경우는 동종 피질골로 외재골 이식을 시행하였다. 평균 연령은 67.1세, 평균 추시 기간은 31.5개월이었다. 전 예에서 방사선학적, 임상적 평가를 시행하였다. 결과: 최종 추시에서 Beals와 Tower의 기준에 따른 결과는 모두 우수 또는 양호였다. 고관절 점수는 평균 94.4점으로 모든 환자의 임상적 평가는 양호하였다. 전 예에서 골절부의 골유합을 얻었다. 합병증으로 대전자 불유합, 표재성 감염, 이식 외재골의 불유합 각각 1예씩을 보였으나 탈구, 심부 감염, 신경 손상 등의 합병증은 없었다. 결론: 대퇴 스템의 해리가 있는 밴쿠버 분류 B2와 B3 골절의 치료는 관혈적 정복과 긴 대퇴 스템 재치환 및 동종 망상골 이식술로 만족할 만한 결과를 얻었지만 장기 추시가 필요할 것으로 생각한다. Purpose: We evaluated the outcome of femoral stem revision for Vancouver B2 and B3 periprosthetic femoral fractures. Materials and Methods: We conducted a retrospective assessment of 15 patients who had received treatment for a periprosthetic unstable femoral fracture after primary hip arthroplasty between May 1997 and September 2009. According to Vancouver classification, 11 patients were type B2 and four were B3. Open reduction and long stem revision were performed in all 15 cases. In Vancouver type B3 fractures, we treated patients with open reduction and long stem revision with an allogenic cancellous bone graft, which is the same as in that used in Vancouver type B2 fractures. An allogenic onlay cortical bone graft was used when additional stability was required. The mean age of patients was 67.1 years at the time of surgery and the mean duration of follow-up was 31.5 months. We described the clinical and radiographic results. Results: Using Beals and Tower’s criteria, fair to good clinical and radiologic results were observed at the latest follow up, with an average Harris hip score of 94.4 points. Fractures were united in all 15 patients. One patient had non-union of the greater trochanter of the femur, one patient had superficial infection, and one patient had non-union of onlay bone graft, however, there were no further complications, such as dislocations, periprosthetic infections, or nerve injuries. There was no loosening of the femoral stems. Conclusion: In Vancouver type B2 and B3 fractures, when there is loosening of the femoral stems, open reduction and long stem revision with allogenic cancellous bone graft provided a satisfactory result. However, long-term follow up is needed.

파워검출 기반의 분산형 TDM-PON MAC 프로토콜

이성근,김일래,이용원,이상록,정대광,황성택,오윤제,박진우,Lee, Sung-Kuen,Kim, Eal-Lae,Lee, Yong-Won,Lee, Sang-Rok,Jung, Dae-Kwang,Hwang, Seong-Taek,Oh, Yun-Je,Park, Jin-Woo 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.2B

In this paper, we have proposed the power detection (PD)-based TDM-PON architecture, which is implemented with a hardware-based decentralized DBA (Dynamic Bandwidth Allocation) algorithm among ONUs, without OLT's intervention. Of particular importance in the proposed approach is that the hardware-based power detection scheme is used to manage the distributed MAC algorithm without any complex, time-consuming and costly software-processing elements for DBA in ONUs and OLT. We evaluate the performance of average packet end-to-end delay in a statistical analysis and numerical analysis. In addition, through simulations with various traffic models, we verified the superior performance of the proposed approach by comparing with the results of other E-PONs. 본 논문에서는 OLT의 중앙집중 제어에 의한 대역폭 중재 없이 ONU간의 분산적인 동적 대역폭 할당을 이룰 수 있는 파워 검출 기반의 TDM-PON의 MAC 프로토콜을 제안하였다. 기존의 E-PON에서 사용하는 소프트웨어 기반의 DBA 방식과 달리, 제안된 방식은 하드웨어 기반의 파워 검출을 활용하여 동적 대역폭 할당 알고리즘을 수행함으로써 간단하고 빠르며 비용효과 측면에서 장점을 가진다. 제안된 가입자 망의 성능 평가는 수식적 분석과 컴퓨터 시뮬레이션을 통하여 수행하였으며, 특히 다양한 트래픽 모델 환경에서 제안된 방식의 성능향상 정도를 기존 E-PON들과 비교 및 분석하였다.

TDM-PON에서 동적 WDM 채널 및 대역폭 할당을 위한 MAC 프로토콜 설계 연구

이성근,김일래,이용원,이상록,정대광,황성택,오윤제,박진우,Lee Sung-Kuen,Kim Eal-Lae,Lee Yong-Won,Lee Sang-Rok,Jung Dae-Kwang,Hwang Seong-Taek,Oh Yun-Je,Park Jin-Woo 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.9B

본 논문에서는 수동형 파워분배기 기반의 TDM-PON 망 구조에서 WDM 파장채널과 전송 대역폭을 동적으로 운용하는 가입자망 구조를 제안하고, 가입자 수를 확대하고 대역폭 활용의 효율성을 증가시킬 수 있는 동적 MAC 프로토콜을 제안하였다. 이를 위하여 OLT와 ONU 사이에 별도의 제어채널을 마련하고, 정보 전송에 요구되는 QoS의 수준과 정보량에 따라 파장채널과 데이터 전송 시간슬롯을 동적으로 운용하도록 하였다. 제안된 가입자망의 성능 평가는 수식적 분석과 컴퓨터 시뮬레이션을 통하여 이루어졌으며, 특히 다양한 트래픽 환경에서 제안된 가입자망 구조의 성능향상 정도를 기존 PON들과 비교 및 분석을 하였다. In this paper, we propose the PON-based access network based on conventional TDM-PON architecture, which utilizes WDM wavelength channel and bandwidth dynamically. It is also described a dynamic MAC protocol in order to increase the number of subscribers and efficiency of resource utilization. Of particular importance in the proposed approach for MAC protocol is that the wavelength channel and time slot for up/downlink is dynamically allocated according to the required QoS level and the amount of data in data transmission, through the dedicated control channel between OLT and ONU. We evaluate the performance of average packet end-to-end delay in a statistical analysis and numerical analysis. In addition, through simulations with various traffic models, we verified the superior performance of the proposed approach by comparing with the results of other E-PONs.

Ongoing Research on the Safety of Nanomaterials in NIFDS

Jong Kwon Lee(이종권),Tae Sung Kim,Hang Sik Roh,Ji Hyun Seok,Won Kuen Seong,Jayoung Jeong 한국실험동물학회 2014 한국실험동물학회 학술발표대회 논문집 Vol.2014 No.2

Investigating the response of zinc oxide nanoparticles on blood cells in vivo and in vitro

A Young Jung,Ji Young Bae,Seon Yeong Park,Dang-Young Kim,Saet Byul Cho,Ji Hyun Yun,Joo Hyun Jee,Hye Kyung Choi,Jun-Young Yang,Ji Hyun Seok,Seung Tae Chung,Hang Sik Roh,Wan-Seob Cho,Won Kuen Seong,Jayo 한국실험동물학회 2014 한국실험동물학회 학술발표대회 논문집 Vol.2014 No.8