• Journal of Chest Surgery
• /
• v.42 no.6
• /
• pp.710-718
• /
• 2009

Background: The Cox maze procedure has been used as a standard surgical treatment for atrial fibrillation for about 20 years. Recently, the creators have used a bipolar radiofrequency electrode (Cox maze IV procedure) instead of the incision and suture (cut-sew) technique to make atrial ablation lesions for persistent atrial fibrillation. We investigated clinical outcomes for the Cox maze procedure with a bipolar radiofrequency electrode and cryoablator in patients with persistent atrial fibrillation, and compared results with clinical outcomes of the cut-sew procedure. Material and Method: Between April 2005 and July 2007, 40 patients with persistent atrial fibrillation underwent Cox maze IV procedure with a bipolar radiofrequency electrode and cryoablator (bipolar radiofrequency group). Surgical outcomes were compared with those of 35 patients who had the cut-sew technique for the Cox maze III procedure. All patients had concomitant cardiac surgery. Postoperatively, the patients were followed up every 1 to 2 months. Result: At 6 months postoperatively, the conversion rate to regular sinus rhythm was not significantly different between the two groups: 95.0% for the bipolar radiofrequency ablation group; 97.1% for the cut-sew technique (p=1.0). At the end of the follow-up period, the conversion rate to regular sinus rhythm was also not significantly different (92.5% vs. 91.6%, p=1.0). In multivariate analysis using a Cox-regression model, the postoperative atrial dimension was an independent determinant of sinus conversion in the bipolar radiofrequency ablation group (hazard ratio 31, p=0.005). In the Cox-regression model for both groups, atrial fibrillation at 6 months postoperatively (hazard ratio 92.24, p=0.003) and the postoperative left atrial dimension (hazard ratio 16.05, p=0.019) were independent risk factors of continuance or recurrence of atrial fibrillation after Cox maze procedures. Aortic cross-clamp time and cardiopulmonary bypass time were significantly shorter in the radiofrequency group than in the cut-sew group. Conclusion: In the Cox maze procedure for patients with persistent atrial fibrillation, the use of bipolar radiofrequency ablation and a cryoablator is as good as the cut-sew technique for conversion to sinus rhythm. The postoperative left atrial dimension is an independent determinant of postoperative continuance and recurrence of atrial fibrillation.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.6
• /
• pp.281-285
• /
• 2010

We propose new identification method of LED location in indoor environment. It can transmit and receive position information and additional data, as applying OOK-SS watermarking method for LED transmission signal. Especially, we use a unipolar form code for watermarking spread code, because LED signal has unipolar characteristic. we analysis LED signal influence and interference with watermarking code, demonstrate usefulness of LED-ID using OOK-SS Watermarking.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.298-298
• /
• 2013

플라즈마 전해산화기술은 알루미늄 소재에 대해 기존의 양극 산화막, 전해 경질크롬 도금 및 플라즈마 세라믹 용사기술 등에 의해 구현할 수 없는 고기능성을 부여하여 월등히 우수한 경도, 내부식, 내마모, 전기절연, 열저항, 피로강도 등을 얻을 수 있는 획기적인 기술이다. 또한 최근 환경에 대한 관심이 점차 높아지면서 친환경적 공정과정과 경금속 소재의 제품에 내구성을 향상시킬 필요성이 높아지고 있다. 이러한 요구에 부합하는 플라즈마 전해 산화기술은 알칼리 수용액 중에서 Al, Ti, Mg 등의 표면에 산화 피막을 형성시키는 기술로써 기존의 양극산화(Anodizing)을 대체 할 수 있다. 본 연구에서는 Al6061을 이용하여 플라즈마 전해산화 공정에 사용되는 전해액의 종류 및 농도, 시간의 변화에 따른 산화 피막의 변화를 내전압 측정 및 FE-SEM, EDS, XRD를 통해 분석하였다. 전해액에 sodium hexameta phosphate과 potassium phosphate를 이용하여 phosphate 종류의 변화에 따른 피막 특성의 변화를 연구하였다. 그로인해 phosphate의 종류 및 농도, 시간 변화를 이용하여 플라즈마 전해산화공정의 산화 피막 물성 제어를 할 수 있다.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.24 no.4
• /
• pp.361-369
• /
• 2008

The purpose of this study is to make porous oxide film on the surfaces of pure Ti through anodic spark discharge in electrolytic solution containing calcium and phosphate ions, to improve osseointergration by treating fluoride agent. In addition, it is to evaluate the fluoride modified effect on the surface. Commercial pure Ti plate with $20{\times}10{\times}2mm$ and Ti wire with a diameter of 1.5mm and a total length of 15mm were used. After making titanium oxide films converted by anodic spark discharge, anodizing was performed. Fluoride was spreaded to titanium laboratory plate and maintained for 30 minutes after anodizing breakdown. Fluoride ion discharge amount was measured per 24 hours after dipping titanium plate into saline (10ml) and sustaining 90rpm in a pyrostat. Some plates and wires were dipped in Hanks solutions for a month to examine biocompatibility using SEM and XRD. $TiO_2$ film formed by anodic discharge technique showed great roughness and uniform pores which were $1{\sim}3{\mu}m$ in a diameter. Roughness of the films treated with anodic discharge after blasting were higher than the turned ones(P<0.05). Rapid surface activity was observed in the samples treated with $TiF_3$ agent, which immersed in Hanks solution for 30 days. Taking the results into consideration, the fluoride modified implant with anodic discharge demonstrates that it makes uniformly porous oxide film on the surface of implant and properly increase roughness for osseointegration. The implants will achieve greater bone integration after short healing time by improving surface activity.

• Mood & Emotion
• /
• v.16 no.3
• /
• pp.134-139
• /
• 2018

Objectives : Treatment for bipolar disorder is often complicated by various clinical situations. We undertook a survey of expert opinions to facilitate clinical decisions in special situations such as weight gain, metabolic syndrome, hyperprolactinemia, genetic counseling, and treatment adherence. Methods : A written survey that asked treatment strategies related to safety and tolerability, was prepared focused on weight gain, antipsychotic related hyperprolactinemia, lamotrigine related skin rash, treatment non-adherence and genetic counseling. Sixty-one experts of the review committee completed the survey. Results : In the case of weight gain related to medications, experts preferred exercise and education for diet-control. First chosen medications were lamotrigine, aripiprazole and ziprasidone. Recommendations based on expert survey results for treatment of bipolar patients in other special situations are outlined. Conclusion : With limitation of expert opinions, authors hope that results of this study provide valuable information to make clinical decisions about treatment of bipolar disorder in complicated situations.

• Korean Journal of Biological Psychiatry
• /
• v.25 no.1
• /
• pp.9-15
• /
• 2018

Objectives This study intended to identify the deficits of cognitive control among patients with bipolar I disorder and their first-degree relatives, and identify the possibility of cognitive control as an endophenotype of bipolar disorder. Methods The study included three groups: euthymic states patients with bipolar I disorder (n = 55), unaffected first-degree relatives of probands with bipolar I disorder (n = 30), and a healthy control group (n = 51), that was matched on age, sex, and years of education. The AX version of the continuous performance test (CPT) was used to examine cognitive control. Error rate, correct response times of each subsets (AX, BX, AY, BY), and d' as an indication of accuracy sensitivity index were calculated. Psychopathology, intelligence, and psychomotor speed were also assessed. Results Patients with bipolar I disorder showed significantly worse error rates in the AX (p = 0.01) and BX (p = 0.02) subsets and d' (p = 0.05) than the others. They also showed more delayed correct response times than the healthy control group and first-degree relatives in all subsets (p < 0.01). But first-degree relatives showed neither high error rates nor delayed correct response times than healthy control group. Conclusions These findings suggest that cognitive control is impaired in bipolar I disorder but less likely to be an endophynotype of bipolar I disorder.

• Journal of the Korean Electrochemical Society
• /
• v.18 no.2
• /
• pp.51-57
• /
• 2015

We report the effect of the impurities including water and bromide in the propylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PMPyr-TFSI) on the electrochemical performance of lithium ion batteries. The several kinds of PMPyr-TFSI electrolytes with different amount of impurities are applied as the electrolyte to the cell with the high potential electrode, $LiNi_{0.5}Mn_{1.5}O_4$ spinel. It is found that the impurities in the electrolytes cause the detrimental effect on the cell performance by tracing the cycleability, voltage profile and Coulombic efficiency. Especially, the polarization and Coulombic efficiency go to worse by both impurities of water and bromide, but the cycleability was not highly influenced by bromide impurity unlike the water impurity.

• Polymer(Korea)
• /
• v.31 no.1
• /
• pp.74-79
• /
• 2007

Polypyrrole (PPy) was made by an emulsion polymerization using iron (III) chloride ($FeCl_3$) as an initiator and dodecyl benzene sulfuric acid (DBSA) as an emulsifier and dopant. Poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) was sulfonated by chlorosulfonic acid (CSA). The cathode was composed of $PPy^+DBS^-$ complex, conductor powder, and PPO or sulfonated poly (2,6-dimethyl-1,4-phenylene oxide) (SPPO) as a binder or dopant. The charge-discharge performance of $PPy^+DBS^-/SPPO$ cathode was increased as the extent of about 50%, than $PPy^+DBS^-/PPO$. This is because SPPO played a role as a binder as well as a dopant. In addition, sulfonation brings out the increase of miscibility between PPy and SPPO, and the increase of contact area between cathode and electrolyte.

• Applied Chemistry for Engineering
• /
• v.23 no.3
• /
• pp.247-252
• /
• 2012

Of late, the development of advanced batteries with high power density and capacity has been indispensible for pushing ahead with much wider applications to electric vehicles and smart IT devices. However, a conventional Li-ion battery contains a limited energy density due to various technological challenges such that other types of Li batteries including Li-S and Li-air have been extensively studied due to their interestingly high energy capacities. Sulfur and oxygen, of which both are cathode materials, showing similar physicochemical characteristics have widely been available which may also contribute to the commercialization of these batteries. In this review, we introduce some perspectives in improving these advanced Li batteries through several approaches such as the provision of porous cathode structures, the optimization of cathode-electrolyte interfaces and the modification of Li anodes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.313-316
• /
• 2002

비철금속 습식 제련용 고효율 장수명의 양극을 개발하기 위해서 산소 과전압이 낮은 $MnO_{2}$를 촉매로 사용하여 반도체 산화물계의 산소선택성 전극을 제조하고 산화물 coating층의 미세구조와 전기화학적 특성을 분석하였다. PVDF : $MnO_{2}$의 함량비플 1 : 1 에서 1 : 40까지 정량적으로 변화시켰고， 용제의 점도에 지배적인 영향을 미치는 DMF의 함량을 각각의 고정된 PVDF : $MnO_{2}$의 함량비에서 변화시켜 용제를 제조하였으며 4% $HNO_{3}$ 용액에 세척된 Pb전극을 1.5 mm/sec 의 속도로 5회 dipping 하였다. PVDF : $MnO_{2}$ = 1 : 6인 경우 PVDF의 양이 증가하고 DMF의 양이 감소할수록 피막층이 두꺼워지고 PVDF : DMF = 4 : 96인 경우 pb 전극의 피막층이 얇기 때문에 박리현상이 일어났으며 이는 산화물 용제의 낮은 점도 때문인 것으로 판단된다. 또한 PVDF : DMF = 10 : 90의 경우는 5회 dipping 하여 약 $150{\mu}m$의 피막층을 형성하였다. PVDF : Mn02의 함량비가 1:1에서 1:6 까지는 DMF의 함량에 무관하게 전극 특성이 나타나지 않았지만 $MnO_{2}$의 양이 상대적으로 증가하면 cycle 이 증가하더라도 거의 일정한 전류 값을 갖고$MnO_2$와 PVDF의 비가 20:1 이상의 조성에서는 균일한 CV 특성을 나타냈다 이는 $MnO_{2}$가 효과적으로 촉매 작용을 한 것으로 판단되며 anodic polarization에 의한 산소 발생 과전압도 약 1.4V 정도로 감소되었다.