Er:YAG laser 조사에 의한 치은연하치석 제거효과

조인구,김영준,김병국,정현주 전남대학교 치의학연구소 2002 구강과학 Vol.14 No.3

The purpose of this in vitro study was to evaluate the efficiency of Er:YAG laser on calculus removal and the morphologic changes and hardness of the irradiated surface at different power settings. This experiment used human teeth which were extracted due to periodontal disease and had a band of calculus. Forty root slabs (5x5mm^2) were made and divided into control group and irradiated groups. Experimental groups were as follows;Control group (root planing), Group 1 (irradiated with laser at 30mj), Group 2(irradiated with laser at 60mJ). and Group 3(irradiated with laser at 100mJ). Twelve root slabs embedded in resin block were used in each group. Er:YAG laser was applied under water irrigation with the tip held perpendicular to the root surface in contact mode. The treatment time was measured until the calculus was removed completely under naked eyes. The efficiency of calculus removal was evaluated by the time for removal. Morphological changes of laser irradiated site were observed under SEM and the surface hardness was measured using a VH tester. The results were as follows; 1. The efficiency of laser scaling was increased with increasing the energy level of irradiation. (p<0.05) 2. The morphological changes such as carbonization, crater and scale-like defects in the irradiated root surface were frequently observed with increasing the energy level. 3. The surface hardness tended to increase at 60mJ and 100mJ irradiated groups than that of control group. From the results evaluting on the efficiency, morphological change, and surface hardness, lower energy level was suggested f'or the clinical application of the Er:YAG laser in scaling.

Surveillance of canine influenza A virus in the Republic of Korea from 2016 to 2021

Seong-In Lim,Min Ji Kim,In-Ohk Ouh,Min-Ji Kim,MiJung Kwon,Gyeong Gook Park,Eui Hyeon Lim,Eun-Ju Kim,Yeun-Kyung Shin,Soo Dong Cho,Bang-hun Hyun,Yoon-Hee Lee 한국예방수의학회 2022 예방수의학회지 Vol.46 No.4

Influenza A viruses (IAVs) are members of the family Orthomyxoviridae and genus Orthomyxovirus. Avian and mammalian species are the host of IAVs, which includes humans and dogs. Canine influenza virus (CIV) is an emerging pathogen that causes severe and acute respiratory diseases in dogs. This study monitored the antigen and antibody against CIV in dogs in the Republic of Korea (ROK) from 2016 to 2021. One thousand and seventy-two nasal swabs and 1,545 blood samples were collected from animal hospitals and animal shelters. Five nasal swabs in 2017 and seven in 2018 from stray dogs were positive for CIV according to RT-PCR. The prevalence of H3N2 CIV ranged from 9.5% to 24.8%, according to the hemagglutination inhibition (HI) assay. On the other hand, none of the serum samples from 2018 to 2021 showed seropositivity against the avian H5, H7, and H9 viruses. The HI titers for H3N2 ranged from 16 to 512. The distribution of HI titer 16–32 was 57.6% in seropositive samples. The pet dogs were vaccinated against CIV, but the stray and military dogs were unvaccinated. In 2017 and 2018, the seroprevalence of CIV in stray dogs was higher than in the other years, and viral RNA was detected in nasal swabs. It may mean previous exposure of stray dogs to CIV. With the increasing number of pet dogs and the close contact between humans and dogs, canines could serve as an intermediate host for transmitting IAVs to humans. Therefore, continuous surveillance of CIV is needed for public health and the potential emergence of novel zoonotic viruses.

흰쥐 대동맥에서 melatonin의 내피 의존적 혈관 이완 작용에 대한 lithium의 영향

김상진,유선봉,조인국,강형섭,김진상,Kim, Shang-Jin,Yu, Xianfeng,Cho, In-Gook,Kang, Hyung-Sub,Kim, Jin-Shang 대한수의학회 2005 大韓獸醫學會誌 Vol.45 No.4

Melatonin, the principal hormone of the vertebral pineal gland, participates in the regulation of cardiovascular system in vitro and in vivo. Lithium inhibits both inositol polyphosphate phosphatase (IPPase) and inositol monophosphatase (IMPase), which are involved in a wide range of signal transduction pathways. The aim of the present study was to assess the effect of lithium on endothelial-dependent relaxation to melatonin and on the melatonin-induced inhibition of contraction by phenylephrine (PE) in isolated rat aorta. Melatonin induced a concentration-dependent relaxation in PE-precontracted in endothelium-intact (+E) aortic rings. Melatonin inhibited a PE-induced sustained contraction in +E aortic rings. These effects of melatonin on relaxation and contractile responses were inhibited by pretreatment with lithium. In PE-precontracted +E aortic rings, the melatonin-induced vasorelaxations and the inhibitory effects of melatonin on maximal contractions were inhibited by endothelium removal or by pretreatment with L-$N^G$-nitro-arginine (L-NNA), 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (ODQ) and nifedipine and verapamil, but not by tetrabutylammonium, clotrimazole and glibenclamide, However, in endothelium-denuded (-E) aortic rings and in the presence of L-NNA and ODQ in +E aortic rings, the melatonin-induced residual relaxations and the melatonin-induced residual contractile responses to PE were not affected by lithium. It is concluded that the inositol phosphate pathway may be involved in endothelial-dependent relaxation induced by melatonin.

Rigorous Design of 22-㎚ Node 4-Terminal SOI FinFETs for Reliable Low Standby Power Operation with Semi-empirical Parameters

Seongjae Cho,Shinichi O’uchi,Kazuhiko Endo,Sang Wan Kim,Younghwan Son,In Man Kang,Meishoku Masahara,James S. Harris,Byung-Gook Park 대한전자공학회 2010 Journal of semiconductor technology and science Vol.10 No.4

In this work, reliable methodology for device design is presented. Based on this method, the underlap length has been optimized for minimizing the gateinduced drain leakage (GIDL) in a 22-㎚ node 4-terminal (4-T) silicon-on-insulator (SOI) fin-shaped field effect transistor (FinFET) by TCAD simulation. In order to examine the effects of underlap length on GIDL more realistically, doping profile of the source and drain (S/D) junctions, carrier lifetimes, and the parameters for a band-to-band tunneling (BTBT) model have been experimentally extracted from the devices of 90-㎚ channel length as well as pnjunction test element groups (TEGs). It was confirmed that the underlap length should be near 15 ㎚ to suppress GIDL effectively for reliable low standby power (LSTP) operation.

Rigorous Design of 22-nm Node 4-Terminal SOI FinFETs for Reliable Low Standby Power Operation with Semi-empirical Parameters

Cho, Seong-Jae,O'uchi, Shinichi,Endo, Kazuhiko,Kim, Sang-Wan,Son, Young-Hwan,Kang, In-Man,Masahara, Meishoku,Harris, James S.Jr,Park, Byung-Gook The Institute of Electronics and Information Engin 2010 Journal of semiconductor technology and science Vol.10 No.4

In this work, reliable methodology for device design is presented. Based on this method, the underlap length has been optimized for minimizing the gateinduced drain leakage (GIDL) in a 22-nm node 4-terminal (4-T) silicon-on-insulator (SOI) fin-shaped field effect transistor (FinFET) by TCAD simulation. In order to examine the effects of underlap length on GIDL more realistically, doping profile of the source and drain (S/D) junctions, carrier lifetimes, and the parameters for a band-to-band tunneling (BTBT) model have been experimentally extracted from the devices of 90-nm channel length as well as pnjunction test element groups (TEGs). It was confirmed that the underlap length should be near 15 nm to suppress GIDL effectively for reliable low standby power (LSTP) operation.

Full-Swing a-IGZO Inverter With a Depletion Load Using Negative Bias Instability Under Light Illumination

In-Tak Cho,Ju-Wan Lee,Jun-Mo Park,Woo-Seok Cheong,Chi-Sun Hwang,Joon-Seop Kwak,Il-Hwan Cho,Hyuck-In Kwon,Hyungcheol Shin,Byung-Gook Park,Jong-Ho Lee IEEE 2012 IEEE electron device letters Vol.33 No.12

<P>A high-performance amorphous indium-gallium-zinc-oxide thin-film transistor (TFT) inverter, which is composed of an enhancement mode driver and a depletion mode load, is implemented by selectively inducing the negative bias illumination temperature stress (NBITS) to the load TFT. Under NBITS, the transfer curve of the load TFT shows a parallel shift into the negative bias direction without a significant change in the subthreshold slope and recovers very slowly after terminating the NBITS even under harsh bias and temperature stress conditions. The proposed inverter shows much improved switching characteristics including higher voltage gain, wider swing range, and higher noise margins compared to the conventional inverter with an enhancement load.</P>

Patterns of Plasma Bullet in Plasma Jets

Gook Hee Han,Je Huan Koo,Duk In Choi,Eun Ha Choi,Guangsup Cho Institute of Electrical and Electronics Engineers 2015 IEEE transactions on plasma science Vol. No.

<P>Composite charges applied to plasma striations were investigated through this paper. Bullets in plasma jets stemming from effective electrons made up of a moving target electron with screening electrons and ions around it were assessed using an atom-like structure induced by an external electric or magnetic field. To maintain a zero total charge, screening electrons and ions were assumed to be spherically and symmetrically distributed around a target moving electron -e, and the surrounding -e or +e was equivalent to the composition of an electric field vortex and an electron. Electrons moving around a spherical orbit were found to have positive charges under a strong electric field but negative charges under a weak field, mainly because the cross-sectional area of the flux was very small. In plasma jets, striations are a phenomenon that may occur when charges gather in the presence of an electric or gauge field. A plasma striation can occur if the effective charge exceeds a critical value determined by setting the derivative of the effective charge to zero, but only if the electric field lines passing through the striation are connected.</P>

실리콘 나노 와이어 기반의 무접합 MOSFET의 최적 설계 및 기본적인 고주파 특성 분석

조성재(Seongjae Cho),김경록(Kyung Rok Kim),박병국(Byung-Gook Park),강인만(In Man Kang) 大韓電子工學會 2010 電子工學會論文誌-SD (Semiconductor and devices) Vol.47 No.10

기존의 n-type metal-oxide-semiconductor field effect transistor(NMOSFET)은 n?/p<SUP>(+)</SUP>/n? type의 이온 주입을 통하여 소스/채널/드레인 영역을 형성하게 된다. 30 ㎚ 이하의 채널 길이를 갖는 초미세 소자를 제작함에 있어서 설계한 유효 채널 길이를 정확하게 얻기 위해서는 주입된 이온들을 완전히 activation하여 전류 수준을 향상시키면서도 diffusion을 최소화하기 위해 낮은 thermal budget을 갖도록 공정을 설계해야 한다. 실제 공정에서의 process margin을 완화할 수 있도록 오히려 p-type 채널을 형성하지 않으면서도 기존의 NMOSFET의 동작을 온전히 구현할 수 있는 junctionless(JL) MOSFET이 연구중이다. 본 논문에서는 3차원 소자 시뮬레이션을 통하여 silicon nanowire(SNW) 구조에 접목시킨 JL MOSFET을 최적 설계하고 그러한 조건의 소자에 대하여 conductance, maximum oscillation frequency(fmax), current gain cut-off frequency(f<SUB>T</SUB>) 등의 기본적인 고주파 특성을 분석한다. 채널 길이는 30 ㎚이며 설계 변수는 채널 도핑 농도와 채널 SNW의 반지름이다. 최적 설계된 JL SNW NMOSFET에 대하여 동작 조건(V<SUB>GS</SUB> = V<SUB>DS</SUB> = 1.0 V)에서 각각 367.5 ㎓, 602.5 ㎓의 f<SUB>T</SUB>, f<SUB>max</SUB>를 얻을 수 있었다. The source/channel/drain regions are formed by ion implantation with different dopant types of n?/p<SUP>(+)</SUP>/n? in the fabrication of the conventional n-type metal-oxide-semiconductor field effect transistor(NMOSFET). In implementing the ultra-small devices with channel length of sub-30 ㎚, in order to achieve the designed effective channel length accurately, low thermal budget should be considered in the fabrication processes for minimizing the lateral diffusion of dopants although the implanted ions should be activated as completely as possible for higher on-current level. Junciontless (JL) MOSFETs fully capable of the the conventional NMOSFET operations without p-type channel for enlarging the process margin are under researches. In this paper, the optimum design of the JL MOSFET based on silicon nanowire (SNW) structure is carried out by 3-D device simulation and the basic radio frequency (RF) characteristics such as conductance, maximum oscillation frequency(f<SUB>max</SUB>), current gain cut-off frequency(f<SUB>T</SUB>) for the optimized device. The channel length was 30 ㎚ and the design variables were the channel doping concentration and SNW radius. For the optimally designed JL SNW NMOSFET, fT and fmax high as 367.5 ㎓ and 602.5 ㎓ could be obtained, respectively, at the operating bias condition (V<SUB>GS</SUB> = V<SUB>DS</SUB> = 1.0 V).

Method to Eliminate Gate and Drain Bias Stresses in Transfer Curves of WSe₂ Field Effect Transistors with Single Channel Pulsed I—V Measurement

Park, Jun-Mo,Cho, In-Tak,Kang, Won-Mook,Park, Byung-Gook,Lee, Jong-Ho American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.5

<P>Intrinsic drain current-gate voltage characteristics (I-D-V-GS) of the WSe2 field effect transistors (FETs) are obtained by adopting single channel pulsed I-V (PIV) measurement. In the transfer curves measured by a typical DC method, the hysteresis is large and affected by a gate bias (V-GS) sweeping range. In addition, the threshold voltage (V-th) shift is observed as a drain bias (V-DS) increases. By adopting the single channel PIV measurement with a short on time (t(on), similar to 10(-4) s), a long off time (t(off), similar to 1 s), and a base voltage (V-base, V-GS during t(off)) of 0 V, the hysteresis-free I-D-V-GS curves are demonstrated regardless of the V-GS sweeping range. Furthermore, we also show that the V-th shift is negligible in the transfer curves measured by the single channel PIV with the V-base of the half of the V-DS, which makes V-GS stress during t(off) identical to the average channel potential. With elimination of the V-GS and V-DS stress, we demonstrated the intrinsic transfer characteristics of the WSe2 FETs showing ignorable hysteresis without V-th shift and remarkably enhanced mobility and conductance.</P>

Feasibility of the Use of RapiGraft and Skin Grafting in Reconstructive Surgery

Yang, Jung Dug,Cho, In Gook,Kwon, Joon Hyun,Lee, Jeong Woo,Choi, Kang Young,Chung, Ho Yun,Cho, Byung Chae Korean Society of Plastic and Reconstructive Surge 2016 Archives of Plastic Surgery Vol.43 No.5

Background Skin grafting is a relatively simple and thus widely used procedure. However, the elastic and structural quality of grafted skin is poor. Recently, various dermal substitutes have been developed to overcome this disadvantage of split-thickness skin grafts. The present study aims to determine the feasibility of RapiGraft as a new dermal substitute. Methods This prospective study included 20 patients with partial- or full-thickness skin defects; the patients were enrolled between January 2013 and March 2014. After skin defect debridement, the wound was divided into two parts by an imaginary line. Split-thickness skin grafting alone was performed on one side (group A), and RapiGraft and split-thickness skin grafting were used on the other side (group B). All patients were evaluated using photographs and self-questionnaires. The Manchester scar scale (MSS), a chromameter, and a durometer were used for the scar evaluation. The average follow-up period was 6 months. Results The skin graft take rates were 93% in group A and 89% in group B, a non-significant difference (P=0.082). Statistically, group B had significantly lower MSS, vascularity, and pigmentation results than group A (P<0.05 for all). However, the groups did not differ significantly in pliability (P=0.155). Conclusions The present study indicates that a simultaneous application of RapiGraft and a split-thickness skin graft is safe and yields improved results. Therefore, we conclude that the use of RapiGraft along with skin grafting will be beneficial for patients requiring reconstructive surgery.