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Magnetic Resonance Imaging: Historical Overview, Technical Developments, and Clinical Applications
Jahng, Geon-Ho,Park, Soonchan,Ryu, Chang-Woo,Cho, Zang-Hee Korean Society of Medical Physics 2020 의학물리 Vol.31 No.3
The authors congratulate the cerebrations for the 30 years of the Korean Society of Medical Physics (http://www.ksmp.or.kr/). The paper is published to recognize the anniversary. Geon-Ho Jahng invited Professor Z. H. Cho to join to submit this manuscript because he has been one of the leaders in the field of magnetic resonance imaging (MRI) during the last 40 years. In this review, we describe the development and clinical histories of MRI internationally and domestically. We also discuss diffusion and perfusion MRI, molecular imaging using MRI and MR spectroscopy (MRS), and the hybrid systems, such as positron emission tomography-MRI (PET-MRI), MR-guided focused ultrasound surgery (MRgFUS), and MRI-guided linear accelerators (MRI-LINACs). In each part, we discuss the historical evolution of the developments, technical developments, and clinical applications.
Synthesis and Properties of Luotonin A Homologues and Their Aza-analogues
Jahng, Yurngdong,Seok Lee, Eung,Gyu Park, Jae,Ill Kim, Seung Japan Institute of Heterocyclic Chemistry 2006 Heterocycles Vol.68 No.1
<P>A series of new 3,2'-polymethylene-2-(quinol-2-yl)-4(3H)-quinazolinones and their aza-analogues were prepared as a homologous series of luotonin A. Their inhibitory activities against topoisomerase and cytotoxicities against selected cancer cell lines were evaluated to show that luotonin A and its aza-analogue were shown significant cytotoxicity. Conformational study revealed that trimethylene-bridged systems were rigid at room temperature with activation energies for interconversion of 15.7 and 14.6 kcal/mol for 3,2'-trimethylene-2-(quinol-2-yl)-4(3H)-quinazolinone and its aza-anlogue, respectively.</P>
Visualizing surface plasmon polaritons by their gradient force.
Jahng, Junghoon,Ladani, Faezeh Tork,Khan, Ryan Muhammad,Li, Xiaowei,Lee, Eun Seong,Potma, Eric Olaf Optical Society of America 2015 Optics letters Vol.40 No.21
<P>A new method is presented for visualizing the electric field distributions associated with propagating surface-plasmon-polariton (SPP) modes directly in the near-field. The method is based on detecting the photo-induced gradient force exerted by the evanescent field onto a sharp and polarizable tip. Using a photo-induced force microscope (PiFM), images of propagating SPPs are obtained on flat gold surfaces.</P>
Synthesis and Properties of Terdentatee with Extra Pyridine Ring and Their Ru(Ⅱ) Complexes
Jahng, Yurngdong,Moon, Seung Wook,Thummel, Randolph P. 영남대학교 약품개발연구소 1997 영남대학교 약품개발연구소 연구업적집 Vol.7 No.-
The synthesis and electronic as well as redox properties of four Ru(Ⅱ) complexes based on the ligand 4'-(4-pyridyl)-3.3';5',3"-bis-dimethylene-2,2‘;6’,2“-terpyridine are reported. Each new complex is of the type [Ru(L)₂]^(??+) and [Ru(tpy)(L)]^(??+), where L is the terdentate ligand with extra pyridine ring at 4¹-position or is a N-methylated ligand and n=2, 3, or 4. Cyclic voltammetry indicates that the first electron added to the complex enters the viologen-type acceptor in N-methylated ligand.
Reaction of Ru( tpy)Cl₃ with N,N,C-Terdentates, 3,2'-Annulated-6-(2"-pyridyl)-2-phenylpyridines
Jahng, Yurngdong,Park, Jae Gyu 영남대학교 약품개발연구소 2000 영남대학교 약품개발연구소 연구업적집 Vol.10 No.-
The reactions of Ru(tpy)CI_(3)(tpy=2.2';6',2"-terpyridine) with new N, N, C-terdentate ligands, 3,2'-annulated-6-(2"-pyridyl)-2-phenylpyridines(1,HL) and the properties of their Ru(Ⅱ) complexes are described. The distri-bution ratio of the two possible Ru(Ⅱ) complexes, a pentaaza-coordinated complex [Ru(tpy)(1-N,N')CI]^(+) and a cycloruthenated complex [Ru(tpy)(La-N,N',C)]^(+) are highly dependent on the length of the polymethylene unit. The trimethylene bridge of the N,N,C-terdentate in pentaaza-coordinated complex is rigid enough to induce an asymmetry in the complex.
Formation of Ruthenium(Ⅱ) Complexes with Unsymmetrical Terdentate Ligands
Jahng, Yurngdong,Thummel, Randolph P.,Bott, Simon G. 영남대학교 약품개발연구소 1997 영남대학교 약품개발연구소 연구업적집 Vol.7 No.-
Three unsymmetrical terdentate ligands, 2-(2'-quinolyl)-1.10-phenanthroline (4), 2-(1'-isquinolyl)-1.10-phenanthroline (5), and 3.3'-dimethylene-2-(2'-quinolyl)-1.10-phenanthroline (6), have been prepared by application of the Friedlander condensation. Ligand 4 forms predominantly a pentaaza-coordinated (N5) complex with Ru(Ⅱ), [Ru(4-N,N,N')(4-N,N)Cl](PF_(6), whose structure was determined by X-ray analysis (C₄₂H_(26)CIF_(6)N_(6)PRu: monoclinic, C2lc, a=29.308(3) A, b=15.295(2) A, c=19.505(2) A, β=107.312(8)˚, V=8298(Ⅰ) A³, Z=8). Ligand 5 forms predominantly a hexaaza-coordinated (N6) complex, [Ru(5-N,N,N')₂. The bridged species 6 shows intermediate behavior, and the rate for interconversion of the N5 to N6 complex has been measured. The stereochemical features of these two binding modes are examined, and both π-stacking and steric effects are invoked to explain the observed behavior, leading to the proposal of a backside displacement mechanism for their interconversion.
The X-ray Crystal Structure of 3, 3' ; 5', 3"-Bis(tetramethylene)-2, 2' ; 6' 2"-terpyridine
Jahng, Yurngdong 영남대학교 자원문제연구소 1994 資源問題硏究 Vol.13 No.-
To help better understand the conformational as well as structural features. a single crystal X-ray analysis of 3,3'; 5',3"-bis(tetrHmethylene)-2,2': 6',2"-terpyridine was undertaken to show this molecule retains Cn symmetry and exists in the monoclinic space group. P2lf.. with four molecules per unit cell, and a = 9.036(4) A, b = 16.741(8) A. c = 12.217(6) A, and☞ = 107.09(3) " as cell constants.