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The SAR analysis of TRPV1 agonists with the α-methylated B-region
Cho, Yongsung,Kim, Myeong Seop,Kim, Ho Shin,Ann, Jihyae,Lee, Jiyoun,Pearce, Larry V.,Pavlyukovets, Vladimir A.,Morgan, Matthew A.,Blumberg, Peter M.,Lee, Jeewoo Elsevier 2012 Bioorganic & medicinal chemistry letters Vol.22 No.16
<P>A series of TRPV1 agonists with amide, reverse amide, and thiourea groups in the B-region and their corresponding α-methylated analogues were investigated. Whereas the α-methylation of the amide B-region enhanced the binding affinities and potencies as agonists, that of the reverse amide and thiourea led to a reduction in receptor affinity. The analysis indicated that proper hydrogen bonding as well as steric effects in the B-region are critical for receptor binding.</P>
Sanghyun Cho,Dae-Geun Jeon,Wan Hyeong Cho,Won Seok Song,Yongsung Kim 대한정형외과학회 2023 Clinics in Orthopedic Surgery Vol.15 No.5
Background: Mechanical failures of tumor endoprosthesis in the distal femur usually require revision surgery. We investigated if the proximal femur host bone can be salvaged by onlay and overlapping allograft in revision surgeries due to aseptic loosening and stem fractures. Methods: We retrospectively reviewed 18 patients (7 men and 11 women) with osteosarcoma around the knee. The entire cohort was classified into three subgroups (no bone graft: 6, onlay allograft: 7, and overlapping allograft: 5) according to our treatment strategy. Results: The median interval from the initial surgery to the revision was 94.5 months (range, 21–219 months), and the median follow-up period from the revision surgery was 88.0 months (range, 24–179 months). At the last follow-up, 9 of the 18 patients maintained their endoprostheses, and the 5-year prosthesis survival rate was 57.9%. Limb survival was 100%. Five-year prosthesis survival rate was 66.7% in the no bone graft group, 85.7% in the onlay allograft group while 30.0% in the overlapping allograft group. In the no bone graft group and onlay allograft group, 66.7% (4/6) and 57.1% (4/7) maintained their revision prostheses while no prostheses survived in the overlapping allograft group. Recurrent stem loosening was observed in 14.2% (1/7) and 60.0% (3/5) of the onlay allograft and overlapping allograft groups, respectively, despite allograft bone union. The complication rate was 66.7% (12/18) in the entire cohort. The most common type of complication was infection (n = 6), followed by aseptic loosening (n = 4) and mechanical failure (n = 2). Conclusions: This study indicates that onlay allograft can be used as a supportive method in revising failed endoprosthesis if the extent of host bone destruction is extensive. However, applying overlapping allograft to secure bone stock showed a high rate of mechanical failures and infection in the long term. Future studies with a larger cohort are necessary to assess the prognostic factors for the higher complication rate in overlapping allograft and the need for overlapping allograft. Surveillance with consideration of the risk of anteromedial osteolysis in allograft and efforts for prevention of periprosthetic infection are essential.
Demonstration of Addressable Organic Resistive Memory Utilizing a PC-Interface Memory Cell Tester
Byungjin Cho,Sunghoon Song,Yongsung Ji,Ho-Gil Choi,Heung Cho Ko,Jae-Suk Lee,Gun-Young Jung,Takhee Lee IEEE 2013 IEEE electron device letters Vol.34 No.1
<P>We demonstrated nonvolatile 8 × 8 array organic memory devices utilizing a PC-interface memory cell tester. The organic memory devices composed of a Ag/poly(3-hexylthiophene-2,5-diyl) (P3HT)/p<SUP>+</SUP> poly-Si structure exhibited excellent memory performance properties, including stable switching behavior, proper statistical distribution, and long retention time. We succeeded in independently addressing and reading the data in the memory cell array using the PC-interface memory cell tester, opening an avenue toward more realistic organic memory device applications.</P>
Organic nonvolatile memory devices with charge trapping multilayer graphene film
Ji, Yongsung,Choe, Minhyeok,Cho, Byungjin,Song, Sunghoon,Yoon, Jongwon,Ko, Heung Cho,Lee, Takhee IOP Pub 2012 Nanotechnology Vol.23 No.10
<P>We fabricated an array-type organic nonvolatile memory device with multilayer graphene (MLG) film embedded in polyimide (PI) layers. The memory devices showed a high ON/OFF ratio (over 10<SUP>6</SUP>) and a long retention time (over 10<SUP>4</SUP> s). The switching of the Al/PI/MLG/PI/Al memory devices was due to the presence of the MLG film inserted into the PI layers. The double-log current–voltage characteristics could be explained by the space-charge-limited current conduction based on a charge-trap model. A conductive atomic force microscopy found that the conduction paths in the low-resistance ON state were distributed in a highly localized area, which was associated with a carbon-rich filamentary switching mechanism. </P>