Efficiency Analysis of Powertrain for Internal Combustion Engine and Hydrogen Fuel Cell Tractor According to Agricultural Operations.

As interest in eco-friendly work vehicles grows, research on the powertrains of eco-friendly tractors has increased, including research on the development of eco-friendly vehicles (tractors) using hydrogen fuel cell power packs and batteries. However, batteries require a long time to charge and have a short operating time due to their low energy efficiency compared with hydrogen fuel cell power packs. Therefore, recent studies have focused on the development of tractors using hydrogen fuel cell power packs; however, there is a lack of research on powertrain performance analysis considering actual working conditions. To evaluate vehicle performance, an actual load measurement during agricultural operation must be conducted. The objective of this study was to conduct an efficiency analysis of powertrains according to their power source using data measured during agricultural operations. A performance evaluation with respect to efficiency was performed through comparison and an analysis with internal combustion engine tractors of the same level. The specifications of the transmission for hydrogen fuel cell and engine tractors were used in this study. The power loss and efficiency of the transmission were calculated using ISO 14179-1 equations, as shown below. Plow tillage and rotary tillage operations were conducted for data measurement. The measurement system consists of four components. The engine data load measurement was calculated using the vehicle's controller area network (CAN) data, the axle load was measured using an axle torque meter and proximity sensors, and fuel consumption was measured using the sensor installed on the fuel line. The calculated capacities, considering the engine's fuel efficiency for plow and rotary tillage operations, were 131.2 and 175.1 kWh, respectively. The capacity of the required power, considering the powertrain's efficiency for hydrogen fuel cell tractors with respect to plow and rotary tillage operations, was calculated using the efficiency of the motor, inverter, and power pack, and 51.3 and 62.9 kWh were the values obtained, respectively. Considering these factors, the engine exhibited an efficiency of about 47.9% compared with the power pack in the case of plow tillage operations, and the engine exhibited an efficiency of about 29.3% in the case of rotary tillage operations. A hydrogen fuel cell tractor is considered suitable for high-efficiency and eco-friendly vehicles because it can operate on eco-friendly power sources while providing the advantages of a motor.

Analysis of the Effect of Tillage Depth on the Working Performance of Tractor-Moldboard Plow System under Various Field Environments.

The purpose of this study was to analyze the tillage depth effect on the tractor-moldboard plow systems in various soil environments and tillage depths using a field load measurement system. A field load measurement system can measure the engine load, draft force, travel speed, wheel axle load, and tillage depth in real-time. In addition, measurement tests of soil properties in the soil layer were preceded to analyze the effect of field environments. The presented results show that moldboard plow at the same tillage depth had a wide range of influences on the tractor's working load and performance under various environments. As the draft force due to soil-tool interaction occurred in the range of 5.6-17.7 kN depending on the field environment, the overall mean engine torque and rear axle torque were up to 2.14 times and 1.67 times higher in hard and clayey soil, respectively, than in soft soil environments. In addition, the results showed tractive efficiency of 0.56-0.73 and were analyzed to have a lugging ability of 67.8% with a 44% maximum torque rise. The engine power requirement in hardpan was similar within 3.6-9.6%, but the power demand of the rear axle differed by up to 18.4%.

Traction Performance Evaluation of the Electric All-Wheel-Drive Tractor.

This study aims to design, develop, and evaluate the traction performance of an electric all-wheel-drive (AWD) tractor based on the power transmission and electric systems. The power transmission system includes the electric motor, helical gear reducer, planetary gear reducer, and tires. The electric system consists of a battery pack and charging system. An engine-generator and charger are installed to supply electric energy in emergency situations. The load measurement system consists of analog (current) and digital (battery voltage and rotational speed of the electric motor) components using a controller area network (CAN) bus. A traction test of the electric AWD tractor was performed towing a test vehicle. The output torques of the tractor motors during the traction test were calculated using the current and torque curves provided by the motor manufacturer. The agricultural work performance is verified by comparing the torque and rpm (T-N) curve of the motor with the reduction ratio applied. The traction is calculated using torque and specifications of the wheel, and traction performance is evaluated using tractive efficiency (TE) and dynamic ratio (DR). The results suggest a direction for the improvement of the electric drive system in agricultural research by comparison with the conventional tractor through the analysis of the agricultural performance and traction performance of the electric AWD tractor.

Weakly Supervised Crop Area Segmentation for an Autonomous Combine Harvester.

Machine vision with deep learning is a promising type of automatic visual perception for detecting and segmenting an object effectively; however, the scarcity of labelled datasets in agricultural fields prevents the application of deep learning to agriculture. For this reason, this study proposes weakly supervised crop area segmentation (WSCAS) to identify the uncut crop area efficiently for path guidance. Weakly supervised learning has advantage for training models because it entails less laborious annotation. The proposed method trains the classification model using area-specific images so that the target area can be segmented from the input image based on implicitly learned localization. This way makes the model implementation easy even with a small data scale. The performance of the proposed method was evaluated using recorded video frames that were then compared with previous deep-learning-based segmentation methods. The results showed that the proposed method can be conducted with the lowest inference time and that the crop area can be localized with an intersection over union of approximately 0.94. Additionally, the uncut crop edge could be detected for practical use based on the segmentation results with post-image processing such as with a Canny edge detector and Hough transformation. The proposed method showed the significant ability of using automatic perception in agricultural navigation to infer the crop area with real-time level speed and have localization comparable to existing semantic segmentation methods. It is expected that our method will be used as essential tool for the automatic path guidance system of a combine harvester.

Estimation of Axle Torque for an Agricultural Tractor Using an Artificial Neural Network.

The objective of this study was to develop a model to estimate the axle torque (AT) of a tractor using an artificial neural network (ANN) based on a relatively low-cost sensor. ANN has proven to be useful in the case of nonlinear analysis, and it can be applied to consider nonlinear variables such as soil characteristics, unlike studies that only consider tractor major parameters, thus model performance and its implementation can be extended to a wider range. In this study, ANN-based models were compared with multiple linear regression (MLR)-based models for performance verification. The main input data were tractor engine parameters, major tractor parameters, and soil physical properties. Data of soil physical properties (i.e., soil moisture content and cone index) and major tractor parameters (i.e., engine torque, engine speed, specific fuel consumption, travel speed, tillage depth, and slip ratio) were collected during a tractor field experiment in four Korean paddy fields. The collected soil physical properties and major tractor parameter data were used to estimate the AT of the tractor by the MLR- and ANN-based models: 250 data points were used for developing and training the model were used, the 50 remaining data points were used to test the model estimation. The AT estimated with the developed MLR- and ANN-based models showed agreement with actual measured AT, with the R2 value ranging from 0.825 to 0.851 and from 0.857 to 0.904, respectively. These results suggest that the developed models are reliable in estimating tractor AT, while the ANN-based model showed better performance than the MLR-based model. This study can provide useful results as a simple method using ANNs based on relatively inexpensive sensors that can replace the existing complex tractor AT measurement method is emphasized.

Analysis of Tillage Depth and Gear Selection for Mechanical Load and Fuel Efficiency of an Agricultural Tractor Using an Agricultural Field Measuring System.

This study was conducted to analyze the effects of tillage depth and gear selection on the mechanical load and fuel efficiency of an agricultural tractor during plow tillage. In order to analyze these effects, we developed an agricultural field measuring system consisting of a load measurement part (wheel torque meter, proximity sensor, and real-time kinematic (RTK) global positioning system (GPS)) and a tillage depth measurement part (linear potentiometer and inclinometer). Field tests were carried out using moldboard plows with a maximum tillage depth of 20 cm and three gear selections (M2H, M3L, and M3H) in a rice stubble paddy field for plow tillage. The average travel speed and slip ratio had the lowest M2H and the highest M3L. M3H had the highest theoretical speed, but the travel speed was 0.13 km/h lower than M3L due to the reduction in the axle rotational speed at deep tillage depth. Regarding engine load, the higher the gear, the greater the torque and the lower the axle rotation speed. The front axle load was not significantly affected by the tillage depth as compared to other mechanical parts, except for the M3H gear. The rear axle load generated about twice the torque of the front wheel and overall, it tended to show a higher average rear axle torque at higher gear selection. The rear axle load and fuel rate were found to be most affected by the combination of the tillage depth and gear selection combination. Overall, field test results show that the M3H had the highest fuel efficiency and a high working speed while overcoming high loads at the same tillage depth. In conclusion, M3H is the most suitable gear stage for plow cultivation, and the higher the gear stage and the deeper the tillage depth during plowing, the higher the fuel efficiency. The results of this study will be useful for analyzing mechanical load and fuel efficiency during farm operations. In a future study, we will conduct load analysis studies in other farming operations that consider various soil mechanics factors as well as tillage depths and gear selections.

Development of a Real-Time Tillage Depth Measurement System for Agricultural Tractors: Application to the Effect Analysis of Tillage Depth on Draft Force during Plow Tillage.

The objectives of this study were to develop a real-time tillage depth measurement system for agricultural tractor performance analysis and then to validate these configured systems through soil non-penetration tests and field experiment during plow tillage. The real-time tillage depth measurement system was developed by using a sensor fusion method, consisting of a linear potentiometer, inclinometer, and optical distance sensor to measure the vertical penetration depth of the attached implement. In addition, a draft force measurement system was developed using six-component load cells, and an accuracy of 98.9% was verified through a static load test. As a result of the soil non-penetration tests, it was confirmed that sensor fusion type A, consisting of a linear potentiometer and inclinometer, was 6.34-11.76% more accurate than sensor fusion type B, consisting of an optical distance sensor and inclinometer. Therefore, sensor fusion type A was used during field testing as it was found to be more suitable for use in severe working environments. To verify the accuracy of the real-time tillage depth measurement system, a linear regression analysis was performed between the measured draft and the predicted values calculated using the American Society of Agricultural and Biological Engineers (ASABE) standards-based equation. Experimental data such as traveling speed and draft force showed that it was significantly affected by tillage depth, and the coefficient of determination value at M3-Low was 0.847, which is relatively higher than M3-High. In addition, the regression analysis of the integrated data showed an R-square value of 0.715, which is an improvement compared to the accuracy of the ASABE standard prediction formula. In conclusion, the effect of tillage depth on draft force of agricultural tractors during plow tillage was analyzed by the simultaneous operation of the proposed real-time tillage depth measurement system and draft force measurement system. In addition, system accuracy is higher than the predicted accuracy of ±40% based on the ASABE standard equation, which is considered to be useful for various agricultural machinery research fields. In future studies, real-time tillage depth measurement systems can be used in tractor power train design and to ensure component reliability, in accordance with agricultural working conditions, by predicting draft force and axle loads depending on the tillage depth during tillage operations.

Simulation of Design Factors of a Clutch Pack for Power-Shift Transmission for an Agricultural Tractor.

The objective of this study is the simulation of the most affected design factors and variables of the clutch pack for the power-shift transmission (PST) of a tractor based measured data. The simulation model, the mathematical model of sliding velocity, a moment of inertia, and clutch engagement pressure of clutch pack were developed using the powertrain and configurations of the real PST tractor. In this study, the sensor fusion method was used to precisely measure the proportional valve pressure by test bench, which was applied to the simulation model. The clutch engagement times were found 1.20 s at all temperatures for determined factors. The engagement pressures have a significant difference at various temperatures (25 to 100 °C) of the hydraulic oils after the 1.20 s but the most affected factors were satisfied with the simulation conditions that ensure the clutch engagement on time. Finally, this sensor fusion method is believed to be helpful in realizing precision agriculture through minimization of power loss and maximum energy efficiency of tractors.

Hepatitis C virus genotype 3 was associated with the development of hepatocellular carcinoma in Korea.

Although hepatitis C virus (HCV) genotype 3 infection is thought to be an important risk factor for hepatocellular carcinoma (HCC), current evidence is limited because only a few Western studies have evaluated the occurrence of HCC in patients with HCV genotype 3 infection. We evaluated the impact of genotype 3 and non-3 on HCC incidence and on disease progression in chronic HCV patients; this is the first study reporting such findings in an Asian population. We performed a retrospective cohort study using the data of 1448 consecutive chronic HCV patients evaluated at three centres in Korea between January 2005 and December 2016. Of these, 604, 675 and 169 had genotype 1, genotype 2 and genotype 3 HCV infections, respectively. Over a mean follow-up period of 53.2 months, 75 and 143 patients of all the patients developed HCC and experienced disease progression, respectively. The incidences of HCC were 1.10, 0.92 and 2.50 per 100 person-years, and those of disease progression were 1.95, 1.62 and 6.72 per 100 person-years for HCV genotypes 1, 2 and 3, respectively. In multivariate Cox regression analysis, genotype 3 was associated with an increased risk of HCC (hazard ratio [HR] = 4.26, 95% confidence interval [CI] = 2.02-8.97) and an increased risk of disease progression (HR = 4.88, 95%; CI = 2.94-8.08). Our study proposes that HCV genotype 3 is an independent risk factor for HCC and disease progression in chronic HCV patients.

Hepatitis C virus genotype affects survival in patients with hepatocellular carcinoma.

BACKGROUND: There is currently no evidence that hepatitis C virus (HCV) genotype affects survival in patients with hepatocellular carcinoma (HCC). This study aimed to investigate whether the HCV genotype affected the survival rate of patients with HCV-related HCC. METHODS: We performed a retrospective cohort study using the data of patients with HCV-related HCC evaluated at two centers in Korea between January 2005 and December 2016. Propensity score matching between genotype 2 patients and non-genotype 2 patients was performed to reduce bias. RESULTS: A total of 180 patients were enrolled. Of these, 86, 78, and 16 had genotype 1, genotype 2, and genotype 3 HCV-related HCC, respectively. The median age was 66.0 years, and the median overall survival was 28.6 months. In the entire cohort, patients with genotype 2 had a longer median overall survival (31.7 months) than patients with genotype 1 (28.7 months; P = 0.004) or genotype 3 (15.0 months; P = 0.003). In the propensity score-matched cohort, genotype 2 patients also showed a better survival rate than non-genotype 2 patients (P = 0.007). Genotype 2 patients also had a longer median decompensation-free survival than non-genotype 2 patients (P = 0.001). However, there was no significant difference in recurrence-free survival between genotype 2 and non-genotype 2 patients who underwent curative treatment (P = 0.077). In multivariate Cox regression analysis, non-genotype 2 (hazard ratio, 2.19; 95% confidence interval, 1.29-3.71) remained an independent risk factor for death. CONCLUSION: Among patients with HCV-related HCC, those with genotype 2 have better survival.

Clinical features and outcomes of abdominal tuberculosis in southeastern Korea: 12 years of experience.

BACKGROUND: Abdominal tuberculosis (TB) is an uncommon form of infection with Mycobacterium tuberculosis in Korea. In this study, we aimed to highlight the clinical features, diagnostic methods, and outcomes of abdominal TB over 12 years in Southeastern Korea. METHODS: A total of 139 patients diagnosed as having abdominal TB who received anti-TB medication from January 2005 to June 2016 were reviewed. Among them, 69 patients (49.6%) had luminal TB, 28 (20.1%) had peritoneal TB, 7 (5.0%) had nodal TB, 23 (16.5%) had visceral TB, and 12 (8.6%) had mixed TB. RESULTS: The most frequent symptoms were abdominal pain (34.5%) and abdominal distension (21.0%). Diagnosis of abdominal TB was confirmed using microbiologic and/or histologic methods in 76 patients (confirmed diagnosis), while the remaining 63 patients were diagnosed based on clinical presentation and radiologic imaging (clinical diagnosis). According to diagnostic method, frequency of clinical diagnosis was highest in patients with luminal (50.7%) or peritoneal (64.3%) TB, while frequency of microscopic diagnosis was highest in patients with visceral TB (68.2%), and frequency of histologic diagnosis was highest in patients with nodal TB (85.2%). Interestingly, most patients, except those with nodal TB, showed a good response to anti-TB agents, with 84.2% showing a complete response. The mortality rate was only 1.4% in the present study. CONCLUSIONS: Most patients responded very well to anti-TB therapy, and surgery was required in only a minority of cases of suspected abdominal TB.

Effect of Ankle Range of Motion (ROM) and Lower-Extremity Muscle Strength on Static Balance Control Ability in Young Adults: A Regression Analysis.

BACKGROUND The purpose of this study was to investigate the effect of ankle ROM and lower-extremity muscle strength on static balance control ability in young adults. MATERIAL AND METHODS This study was conducted with 65 young adults, but 10 young adults dropped out during the measurement, so 55 young adults (male: 19, female: 36) completed the study. Postural sway (length and velocity) was measured with eyes open and closed, and ankle ROM (AROM and PROM of dorsiflexion and plantarflexion) and lower-extremity muscle strength (flexor and extensor of hip, knee, and ankle joint) were measured. Pearson correlation coefficient was used to examine the correlation between variables and static balance ability. Simple linear regression analysis and multiple linear regression analysis were used to examine the effect of variables on static balance ability. RESULTS In correlation analysis, plantarflexion ROM (AROM and PROM) and lower-extremity muscle strength (except hip extensor) were significantly correlated with postural sway (p<0.05). In simple correlation analysis, all variables that passed the correlation analysis procedure had significant influence (p<0.05). In multiple linear regression analysis, plantar flexion PROM with eyes open significantly influenced sway length (B=0.681) and sway velocity (B=0.011). CONCLUSIONS Lower-extremity muscle strength and ankle plantarflexion ROM influenced static balance control ability, with ankle plantarflexion PROM showing the greatest influence. Therefore, both contractile structures and non-contractile structures should be of interest when considering static balance control ability improvement.

Visual Outcome and Patient Satisfaction of Low-Power-Added Multifocal Intraocular Lens.

PURPOSE: To evaluate visual outcome and patient satisfaction following implantation of multifocal intraocular lenses (IOLs) with a +1.5 diopters (D) addition compared with monofocal IOLs. METHODS: This prospective, nonrandomized, comparative case series involved 48 eyes (24 patients) who underwent cataract surgery with implantation of low-power-added multifocal IOLs (LS313-MF15; multifocal group) and 48 eyes (24 patients) with conventional monofocal IOLs (CTS204; monofocal group). Visual acuity (VA), defocus curves, refraction, contrast sensitivity, glare, ocular optical quality, and scores in questionnaire were assessed 6 months postoperatively. RESULTS: Uncorrected VA at intermediate and near distance tended to be better in the multifocal group, with significant differences at 50 cm (P=0.03). The defocus curve showed significantly different VA at vergences of -1.5 and -2.0 D (P=0.02 and P=0.03, respectively). Results of postoperative refraction, contrast sensitivity, glare, and optical quality were similar (P>0.05), although coma-like aberration was higher in the multifocal group (P=0.04). Despite of similar levels of visual disturbances (P>0.05), disturbances in activities and spectacle use at intermediate working distance were significantly less frequent in the multifocal group (P=0.03 and P=0.04, respectively). Multifocal group showed significantly greater overall satisfaction (P=0.02). CONCLUSIONS: Low-power-added multifocal IOLs yielded better intermediate and near vision without increasing optical phenomena compared with monofocal IOLs.

Comparing the Clinical Features and Outcomes of Acute Hepatitis E Viral Infections with Those of Acute Hepatitis A, B, and C Infections in Korea.

OBJECTIVES: This study investigated the etiology of acute viral hepatitis and compared the clinical features of hepatitis E virus (HEV) infections with those of other acute viral hepatitis infections in Korea. METHODS: This study included 2,357 consecutive patients who were diagnosed with acute hepatitis, based on acute illness with jaundice or elevated alanine aminotransferase levels (>100 IU/L), between January 2007 and January 2016. Acute viral infections were observed in 23 (19.8%) patients with HEV, 49 (42.2%) patients with hepatitis A virus, 28 (24.1%) patients with hepatitis B virus, and 16 (13.8%) patients with hepatitis C virus. RESULTS: The incidence of acute HEV infection was higher among older patients (median age: 49 years) and male patients (69.6%), and was associated with the consumption of undercooked or uncooked meat (43.5%). Half of the acute HEV infections involved underlying liver disease, such as alcoholic liver disease, chronic hepatitis B, common bile duct stones, and autoimmune hepatitis. Two HEV-infected patients were diagnosed with Guillain-Barré syndrome, although no patients developed fulminant hepatitis. CONCLUSION: Our findings indicate that HEV infection in Korea is frequently transmitted through the consumption of raw meat and may cause acute or chronic liver disease.

Fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography for the detection of proximal synchronous lesions in patients with obstructive colorectal cancer.

BACKGROUND AND AIM: We aimed to investigate the ability of fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) to detect synchronous neoplasms, specifically obstructive colorectal cancer (CRC) and CRC in the proximal colon and to suggest a management strategy based on FDG PET/CT findings. METHODS: From the CRC surgery database of our institution, 518 patients with obstructive CRC whose proximal colon could not be examined by colonoscopy and who underwent preoperative FDG PET/CT were eligible for this study. Of these, final analyses were performed in 345 patients who had reference standards for the proximal colon, which were a surgical colectomy specimen and/or postsurgical colonoscopy. The per-patient and per-lesion performances of FDG PET/CT for synchronous CRC diagnosis were determined. RESULTS: Of 345 patients, 14 (4.1%) had 14 proximal synchronous CRCs. Thirty-four patients showed 39 areas of abnormal FDG uptake on PET/CT in the colon proximal to the obstructive CRC. PET/CT detected all of the 14 proximal synchronous CRCs. The per-patient PET/CT sensitivity, specificity, positive predictive value, and negative predictive value for proximal synchronous CRC were 100%, 93.9%, 41.2%, and 100%, respectively. Per-lesion values were 100%, 92.6%, 35.9%, and 100%, respectively. The per-lesion sensitivity and negative predictive value of PET/CT for advanced adenoma were 45.5% and 92.7%, respectively. CONCLUSIONS: The FDG PET/CT shows a high sensitivity and negative predictive value for the detection of proximal synchronous CRC in patients with obstructive CRC, enabling negative findings in the proximal colon on PET/CT to definitively exclude proximal synchronous CRC. Preoperative PET/CT recommended to determine the proper surgical plan in patients with obstructive CRC.

Physicians Should Provide Shared Decision-Making for Anti-TNF Therapy to Inflammatory Bowel Disease Patients.

Shared decision-making may increase the effectiveness of inflammatory bowel disease (IBD) treatment, as different anti-tumor necrosis factor (anti-TNF) administrations may have different effects on the quality of life (QOL). Patient preference is integral to the selection of anti-TNFs and their routes of administration, however, previous studies on the patient preference to anti-TNFs are inconsistent and limited. We evaluated the predictive factors for preferences to anti-TNF administrations in IBD patients between March and August in 2015. Consecutive adult IBD patients who received care at one of four university hospitals in Korea were invited to participate in this study. Patients were administered questionnaires about their preferences regarding anti-TNF therapy and QOL. During the study period, 322 IBD patients completed the questionnaires. IBD patients preferred intravenous anti-TNFs to subcutaneous anti-TNFs (2.4:1), and 58.4% of patients preferred shared decision-making. When comparing subcutaneous anti-TNF therapy with intravenous anti-TNF therapy, patients with higher income levels, patients who experienced adverse events with prior medication and patients with a longer disease duration preferred subcutaneous anti-TNF therapy over intravenous anti-TNF therapy (P = 0.043, P = 0.000, and P = 0.029, respectively). In a logistic regression analysis, high income level (odds ratio [OR] 2.0; 95% confidence interval [CI] 1.1-3.5; P = 0.026) and an adverse event with prior medication (OR 4.0; 95% CI 2.2-7.2; P = 0.000) and were found to be independent predictors for preference to subcutaneous anti-TNF therapy. Therefore, physicians should share decision-making with their IBD patients regarding the mode of anti-TNF administration.

Multifocal Intraocular Lens Results in Correcting Presbyopia in Eyes After Radial Keratotomy.

OBJECTIVES: To report results of multifocal intraocular lens (IOL) implantation in 2 patients with refractive error and presbyopia after previous radial keratotomy (RK). METHODS: A refractive multifocal IOL with rotational asymmetry (LS313-MF30; Oculentis, Berlin, Germany) was implanted. RESULTS: The first patient was a 60-year-old man with myopia who underwent unilateral RK 20 years before. His uncorrected distance visual acuity (UDVA) was 20/400, and his distance corrected near vision was J9 in both eyes. Six months after bilateral surgery, his binocular UDVA and uncorrected near visual acuity (UNVA) improved to 20/20 and J1, respectively, although he experienced diurnal fluctuation. The second patient was a 55-year-old woman with hyperopia who underwent bilateral RK 18 years before. Uncorrected distance visual acuity was 20/25 in both eyes, but UNVA was between J9 and J10. Three months after unilateral surgery, UDVA and UNVA of the postsurgical eye improved to 20/20 and J1, respectively. Neither patient reported any significant photic phenomena, and both were satisfied with the results of treatment. CONCLUSIONS: The desirable clinical outcomes and levels of satisfaction expressed by these patients indicate that surgery using this particular multifocal IOL may benefit presbyopic patients with previous RK.

Does Stenting as a Bridge to Surgery in Left-Sided Colorectal Cancer Obstruction Really Worsen Oncological Outcomes?

BACKGROUND: Although self-expandable metal stents are used as a bridge to surgery in patients with colorectal cancer obstruction, their long-term oncological outcomes are unclear. OBJECTIVE: The aim of this study was to investigate long-term oncological outcomes of self-expandable metal stents as a bridge to surgery (stent group) compared with direct surgery (direct operation group) in patients with left-sided colorectal cancer obstruction. DESIGN: This was a retrospective chart review. SETTINGS: This study was conducted at a single tertiary academic center. PATIENTS: Of 113 patients who underwent curative surgery for left-sided colorectal cancer obstruction at Asan Medical Center between 2005 and 2011, 42 underwent direct surgery and 71 underwent self-expandable metal stent insertion followed by elective surgery. After 1:1 propensity-score matching, 42 patients were enrolled in both groups, and their postsurgical outcomes were compared. MAIN OUTCOME MEASURES: The primary outcomes of this study were long-term oncological outcomes, including overall survival and recurrence-free survival of patients in both groups. RESULTS: Three- and 5-year overall survival rates were similar in the stent (87.0% and 71.0%) and direct operation (76.4% and 76.4%) groups (p = 0.931). Three- and 5-year recurrence-free survival rates were also similar in the stent (91.9% and 66.4%) and direct operation (81.2% and 71.2%) groups (p = 0.581), as were postsurgical complication rates (9.5% and 16.7%; p = 0.344). No patient in either group experienced a permanent stoma. LIMITATIONS: This study was limited by its small patient numbers and retrospective nature. CONCLUSIONS: The long-term oncological outcomes of self-expandable metal stents as a bridge to surgery may not be inferior to those of direct surgery for left-sided colorectal cancer obstruction.

Hepatitis C and not Hepatitis B virus is a risk factor for anti-tuberculosis drug induced liver injury.

BACKGROUND: The risk of anti-tuberculosis (TB) drug-induced liver injury (DILI) in patients with chronic viral hepatitis (CVH) is not clear. The aim of this study was to investigate incidence and risk factors associated with TB DILI in CVH and non-CVH patients. METHODS: Retrospectively, a total of 128 CVH patients who received anti-TB medication from January 2005 to February 2014 were reviewed. Among these, 83 patients had hepatitis B virus (HBV), 41 patients had hepatitis C virus (HCV) and 4 patients were dual hepatitis B and hepatitis C virus co-infected (HBV + HCV) with 251 non-CVH patients who received anti-TB medication selected as the controls. There were no human immunodeficiency virus co-infected patients. Risk factors for DILI were analyzed using cox regression analysis. RESULTS: The incidence of DILI was significantly higher in the HCV group (13/41 [31.7%], p < 0.001) and HBV + HCV groups (3/4 [75.0%], p = 0.002) compared to the control group (25/251 [10.0%]). The incidence of transient liver function impairment in the hepatitis B virus group was higher than in the control group (18/83 [21.7%] vs. 27/251 [10.8%] p = 0.010), but not in DILI (11/83 [13.3%] vs. 25/251 [10.0%], p = 0.400). In total patients, HCV, HBV + HCV co-infection, older age, and baseline liver function abnormality were independent factors of DILI. CONCLUSIONS: It is recommended to carefully monitor for DILI in patients with HCV or HBV/HCV co-infection, older age, and baseline liver function abnormality.

Long-Term Outcomes of Infliximab Treatment in 582 Korean Patients with Crohn's Disease: A Hospital-Based Cohort Study.

BACKGROUND AND AIMS: To date, no large-scale studies have evaluated long-term outcomes of infliximab (IFX) treatment in Korean patients with Crohn's disease (CD). METHODS: We analyzed long-term clinical responses to IFX in 582 Korean CD patients who received scheduled IFX treatments at Asan Medical Center. Clinical responses were defined as maintaining IFX without major abdominal surgery (MAS) or dose intensification. RESULTS: Between February 2002 and July 2015, a total of 11,990 IFX infusions were administered to 582 Korean patients with CD over a median period of 36 months. At the end of follow-up, 316 (54.3 %) were still receiving IFX without MAS (71 patients, 12.2 %) or dose intensification (86 patients, 14.8 %). IFX was stopped in 109 (18.7 %) patients because of a loss of response (48 patients, 8.2 %), adverse events (30 patients, 5.2 %), or patient preferences or problems with reimbursement (31 patients, 5.3 %). The cumulative survival for maintenance of IFX without MAS or dose intensification was 89.0, 75.9, 68.3, and 50.8 % at 1, 2, 3, and 5 years, respectively. Multivariate regression analysis identified older age at the initiation of IFX (≥40 years, P = 0.006) and a longer disease duration (≥3 years, P = 0.020) as independent positive predictors of a poorer response to IFX. CONCLUSIONS: The long-term efficacy of IFX in a large, real-life cohort of Korean patients with CD appears to be similar to that in previously published Western studies. Our findings support the early use of IFX to obtain better clinical outcomes.