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Introduction Gallstone disease is common morbidity in elderly (age ≥ 65 years old). Laparoscopic cholecystectomy is increasingly performed in an ever elderly. However, there are no clarified standards for treatment for asymptomatic cholelithiasis in elderly. The purpose of this study was to compare postoperative outcomes of elderly with those of younger populations and to suggest an appropriate age for preventive cholecystectomy before the risk increases. Methods In a prospective Korea Cholecystectomy Quality Improvement Program cohort including 18 institutions from October 2016 to March 2017, 2,610 patients who underwent laparoscopic cholecystectomy for benign gallbladder disease were enrolled. Various characteristics, preoperative findings, operative findings were compared between two groups (age < 65 years old versus age ≥ 65 years old). Results Increasing age was significantly associated with increased rates of overall complications (odds ratio [OR]: 1.79, CI 95%: 1.45-2.20), major complication (OR: 1.64, CI 95%: 1.35-2.08), risk of conversion to open cholecystectomy (OR: 2.00, CI 95%: 1.76-2.28), and was significantly associated with increased length of stay (MD: 2.56 days, CI 95%: 1.24-3.42). Differences in mortality and bile duct injury were non-significant. And most appropriate age that postoperative risk increases is 71 years old (AUC 0.74). Conclusions Postoperative outcomes such as overall and major complications appear to be significantly higher in elderly. Even with asymptomatic cholelithiasis, if the size is more than 1 cm, it is better to recommend surgery before the patient's age reaches 71.

Linearity characteristics of hetero-gatedielectric tunneling field-effect transistors (HG TFETs) have been compared with those of high-k-only and SiO₂-only TFETs in terms of IIP3 and P1dB. It has been observed that the optimized HG TFETs have higher IIP3 and P1dB than high-k-only and SiO₂-only TFETs. It is because HG TFETs show higher transconductance (g m ) and current drivability than SiO₂-only TFETs and gm less sensitive to gate voltage than high-k-only TFETs.

The steady scaling-down of semiconductor device for improving performance has been the most important issue among researchers. Recently, as low-power consumption becomes one of the most important requirements, there have been many researches about novel devices for low-power consumption. Though scaling supply voltage is the most effective way for low-power consumption, performance degradation is occurred for metal–oxide–semiconductor field-effect transistors (MOSFETs) when supply voltage is reduced because subthreshold swing (SS) of MOSFETs cannot be lower than 60 mV/dec. Thus, in this thesis, hetero-gate-dielectric tunneling field-effect transistors (HG TFETs) are investigated as one of the most promising alternatives to MOSFETs. By replacing source-side gate insulator with a high-k material, HG TFETs show higher on-current, suppressed ambipolar current and lower SS than conventional TFETs. Device design optimization through simulation was performed and fabrication based on simulation demonstrated that performance of HG TFETs were better than that of conventional TFETs. Especially, enlargement of gate insulator thickness while etching gate insulator at the source side was improved by introducing HF vapor etch process. In addition, the proposed HG TFETs showed higher performance than our previous results by changing structure of sidewall spacer by high-k etching process.

In recent years, the research for electric power usage reduction in a house has been widely studied. Home energy management system (HEMS) is become one of major applications to handle many smart electrical devices inside house that proves its electricity usage reduction efficiently. However, HEMS has a critical issue which cannot control non-smart devices at home. Saving unnecessary energy usage for legacy devices remains research area to prevent from expansions of energy waste for users. In this paper, an intelligence inference control approach based on the adaptive neural-fuzzy inference system (ANFIS) is proposed for legacy devices. The approach based on ANFIS focuses to reduce computation of training time by performing regeneration and resampling approach compared to conventional ANFIS.

Background/Aims: We examined the ischemia-modified albumin (IMA) level during exercise in patients with coronary artery disease (CAD). Methods: Forty patients with a history of chest pain underwent both symptom-limited treadmill exercise stress testing and coronary angiography within one week. During the treadmill tests, blood samples were obtained at baseline and 5 min after exercise to measure the serum IMA level. Results: Of the 40 patients, fourteen (35%, CAD group) had significant coronary artery stenosis, while the other 26 (65%, non-CAD group) did not. The baseline and post-exercise IMA levels in the two groups did not differ significantly (105.2±7.2 vs. 107.7±6.7 U/mL at baseline and 93.1±10.1 vs. 94.8±5.7 U/mL at post-exercise in the CAD and non-CAD groups, p=0.29 and 0.57, respectively). The changes in IMA after exercise did not differ either (-10.4±7.5 vs. -14.0±7.6 U/mL in the CAD and non-CAD groups, respectively, p=0.10). Similarly, the change in IMA between the exercise ECG test positive (TMT positive, n=9) and negative (TMT negative, n=20) groups did not differ (-14.63±5.19, vs -8.50±9.01 U/mL, p=0.15, in the TMT positive and negative groups, respectively). Conclusions: Our results suggest that IMA has limitation in detecting myocardial ischemia during symptom-limited exercise stress tests.