Kyung-Ho Choi

BACKGROUND: Training beginners of the pedicle screw instrumentation technique in the operating room is limited because of issues related to patient safety and surgical efficiency. Three-dimensional (3D) printing enables training or simulation surgery on a real-size replica of deformed spine, which is difficult to perform in the usual cadaver or surrogate plastic models. The purpose of this study was to evaluate the educational effect of using a real-size 3D-printed spine model for training begin

Abstract We have developed the high‐resolution auto‐stereoscopic 3D display for the first time in the world. For this, we suggested time division(TD) parallax barrier method. For the time division multiplexing image separation, we have adapted 2.2″ AMOLED panel for Imager and we have fabricated fast driving circuit, which operated in more than 240Hz frame rate. Also we have designed and fabricated OCB mode LC barrier shutter for fast responses. We can see 3‐D image at 300mm viewing distance with

Near Field Communication (NFC) is widely used as a contactless communication technology in mobile phones for mobile payments. However, achieving payment security is challenging due to the authentication between the NFC-enabled mobile phone users and the merchants. Attackers can use the vulnerabilities of card payment transactions to compromise the NFC communication message and then transmit the wrong payment information to the communicators. An efficiency key authentication scheme is proposed to

Platelets in LP-PRP release growth factors such as PDGF, IGF-1, TGF-β1 and VEGF, and these growth factors have a promoting effect for human fibroblast proliferation, one of the important mediators of wound healing. These results suggest that growth factors derived from LP-PRP enhance the proliferation of human fibroblast.

Abstract Two series of new poly(amide imide)s having ( n ‐alkyoxy)phenyloxy side branches with various lengths, poly{ p ‐phenyleneiminoterephthaloylimino‐ p ‐phenylene[3,6‐di( n ‐alkyloxy)phenyloxy]pyromellitimide}s ( PC m TA s, m = 4, 8, 12) and poly{ p ‐phenyleneiminosebacoylimino‐ p ‐phenylene[3,6‐di( n ‐alkyloxy)‐phenyloxy]‐ pyromellitimide}s ( PC m SeA s, m = 4, 8, 12), were prepared by condensation of terephthalamide‐ N,N ′‐4,4′‐dianiline ( TA ) and sebacamide‐ N,N ′‐4,4′‐dianiline ( SeA )

First and second generations of 1 → (2 + 1) C-branched metallodendrimers were prepared employing terpyridine−Ru II −terpyridine connectivity. Each surface dendron is comprised of a terpyridinyl (focal group), a diester (capable of easy hydrolysis), and a terminal adamantyl moiety (for encapsulation). Internal incorporation of counterbalancing carboxylate moieties derived by ester cleavage with formic acid and subsequent treatment of the intermediate diacid with base gave access to overall charge

An excellent transparent film with effective absorption property in near-infrared (NIR) region based on cesium-doped tungsten oxide nanoparticles was fabricated using a facile double layer coating method via the theoretical considerations. The optical performance was evaluated; the double layer-coated film exhibited 10% transmittance at 1,000 nm in the NIR region and over 80% transmittance at 550 nm in the visible region. To optimize the selectivity, the optical spectrum of this film was correla

Abstract In this article, photosensitive polyimides (PSPIs) with photosensitive groups, o ‐nitrobenzyl ether groups (Nb), were successfully synthesized based on 2,2′‐dihydroxy benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride and on diamine containing ethylene glycol chains (ODA). Also, a series of polyimide (PI), ODA‐1‐PI, ODA‐3‐PI, and ODA‐5‐PI with a number of ethylene glycol chains of 1, 3, and 5 were prepared to investigate the relationship between structure and solubility. Interestingly,

울릉도 민속식물 31분류군 49점 추출물을 대상으로 최종농도 <TEX>$50{\mu}g/mL$</TEX>로 LPS에 의해 유도된 RAW 264.7 대식세포의 NO 생성량을 조사하였다. 그 결과, 다래(Actinidia arguta) 잎 가지, 헛개나무(Hovenia dulcis) 잎, 동백나무(Camellia japonica) 잎 가지, 말오줌나무(Sambucus sieboldiana var. pendula) 잎 가지, 왕호장근(Fallopia sachalinensis) 뿌리 순으로 항염 활성이 우수하게 나타났다. 이 중에서 다래 잎 가지, 헛개나무 잎, 동백나무 잎 가지 추출물을 LPS로 유도된 Raw 264.7 대식세포에서 최종농도가 10, 20, 40, <TEX>$50{\mu}g/mL$</TEX>로 처리하여 NO 생성량과 세포생존율, <TEX>$PGE_2$</TEX> 생성량을 측정하였다. 그 결과 다래 잎 가지(<TEX>$IC_{50}=29.21{\mu}g/mL$</TEX>),

Skin layers serve as a barrier against unexpected critical changes in the body due to environmental factors. Excessive ultraviolet (UV) B exposure increases the levels of age-related factors, leading to senescent cells and damaged skin tissues. Widely used as a dietary supplement, konjac (Amorphophallus konjac) glucomannan (KGM) has shown skin regeneration potential in patch or sheet form with anti-inflammatory or immunosuppressive effects. However, the ability of KGM to reconstitute senescent/d

Abstract Summary: New aromatic polyamides containing two n ‐alkylphenylimide units fused to the main chain were prepared by the activated polyamidation of 3,6‐di(4‐carboxyphenyl)‐ N , N′ ‐di(4‐ n ‐alkylphenyl)pyromellitimides ( C m DA , m = 0, 8, 12, 16) with oxy‐4,4′‐dianiline in a mixture of N ‐methylpyrrolidone and pyridine (Py) in the presence of triphenyl phosphite and CaCl 2 . The imide‐containing dicarboxylic acid monomers were synthesized by the imidization of 3,6‐di(4‐carboxyphenyl)pyro