Well-Balanced Ambipolar Charge Transport of Diketopyrrolepyrrole-Based Copolymers: Organic Field-Effect Transistors and High-Voltage Logic Applications.

A poly (3,6-bis(thiophen-2-yl)-2,5-bis(2-decyltetradecyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione-co-(2,3-bis(phenyl)acrylonitrile)) (PDPADPP) copolymer, composed of diketopyrrolopyrrole (DPP) and a cyano (nitrile) group with a vinylene spacer linking two benzene rings, is synthesized via a palladium-catalyzed Suzuki coupling reaction. The electrical performance of PDPADPP in organic field-effect transistors (OFETs) and circuits is investigated. The OFETs based on PDPADPP exhibit typical ambipolar transport characteristics, with the as-cast OFETs demonstrating low field-effect hole and electron mobility values of 0.016 and 0.004 cm2  V-1  s-1 , respectively. However, after thermal annealing at 240 °C, the OFETs exhibit improved transport characteristics with highly balanced ambipolar transport, showing average hole and electron mobility values of 0.065 and 0.116 cm2  V-1  s-1 , respectively. To verify the application of the PDPADPP OFETs in high-voltage logic circuits, compact modeling using the industry-standard small-signal Berkeley short-channel IGFET model (BSIM) is performed, and the logic application characteristics are evaluated. The circuit simulation results demonstrate excellent logic application performance of the PDPADPP-based ambipolar transistor and illustrate that the device annealed at 240 °C exhibits ideal circuit characteristics.

Ideal Timing of Discontinuation of Antiplatelet Agents Before Gastric Endoscopic Submucosal Dissection for Reducing Delayed Bleeding.

BACKGROUND AND AIMS: This study aimed to evaluate whether the use of antiplatelet agents increases the risk of bleeding after gastric endoscopic submucosal dissection (ESD) and to determine the appropriate time to discontinue antiplatelet agents to minimize complications. METHODS: This retrospective observational study utilized a collected dataset of patients who underwent ESD for gastric adenoma and cancer between January 2010 and December 2020. Patients were classified into three groups according to antiplatelet agent use and discontinuation status. We investigated the risk of post-ESD bleeding with different interruption times and antiplatelet agent types. RESULTS: Of 1879 patients, 1389 were non-users, 190 were in the continuous group, and 203 were in the interrupted group. The rates of overall and delayed bleeding were significantly higher in patients who continued or were interrupted within three days before ESD than in the non-users and interrupted group (6.3% vs. 1.2%, p < 0.001, 6.3% vs. 2.5%, p = 0.01, respectively). Significant differences in delayed bleeding between the continuous and interrupted groups decreased with longer cessation periods. In multivariate analysis, continuous antiplatelet agents were still the strongest risk factor for bleeding (OR 2.81, 95% CI 1.14-6.90). Lower third location and longer procedure times were also independent risk factors for post-ESD bleeding (OR 2.75; 95% CI 1.08-6.97; OR 1.02; 95% CI 1.01-1.02). CONCLUSION: Continuous antiplatelet agent use increases the risk of delayed bleeding after gastric ESD. Therefore, the optimal timing of interruption, rather than the type of antiplatelet agent, should be considered to avoid an additional risk of bleeding and thromboembolism.

Lensless Three-Dimensional Imaging under Photon-Starved Conditions.

In this paper, we propose a lensless three-dimensional (3D) imaging under photon-starved conditions using diffraction grating and computational photon counting method. In conventional 3D imaging with and without the lens, 3D visualization of objects under photon-starved conditions may be difficult due to lack of photons. To solve this problem, our proposed method uses diffraction grating imaging as lensless 3D imaging and computational photon counting method for 3D visualization of objects under these conditions. In addition, to improve the visual quality of 3D images under severely photon-starved conditions, in this paper, multiple observation photon counting method with advanced statistical estimation such as Bayesian estimation is proposed. Multiple observation photon counting method can estimate the more accurate 3D images by remedying the random errors of photon occurrence because it can increase the samples of photons. To prove the ability of our proposed method, we implement the optical experiments and calculate the peak sidelobe ratio as the performance metric.

Open-Air Testing of Dual-Comb Time-of-Flight Measurement.

We configured a long-distance ranging apparatus to test the principle of dual-comb time-of-flight measurement using ultrashort lasers. Emphasis was given to the evaluation of open-air performance quantitatively in terms of the measurement resolution and stability. The test results revealed that our dual-comb asynchronous optical pulse sampling permits micrometer-resolved ranging with a repeatability of 2.05 µm over a 648 m distance in dry weather conditions. Further atmospheric effects were evaluated in three different weather conditions with corresponding Allan deviations. Finally, the capability of simultaneous determination of multiple targets was verified with the potential of advanced industrial applications, such as manufacturing, surveying, metrology, and geodesy.

Extremely Electron-Withdrawing Lewis-Paired CN Groups for Organic p-Dopants.

P-type chemical doping (p-doping) is a key technique to modulate the optical, electrical, and electronic properties of organic semiconductors. However, typical functional groups in organic p-dopants have insufficient electron-withdrawing strength, and the inevitable diffusion of dopants in host matrices degrades doping stabilities. Herein, we utilize extremely electron-withdrawing Lewis-paired CN groups as a new class of building blocks for designing unprecedentedly strong organic p-dopants with excellent doping stability. Various Lewis acids are paired with CN-functionalized conjugated molecules in the solution state, which strengthens the electron-withdrawing properties of CN groups almost twofold. The large dopants afford outstanding doping stability against continuous heating and long-term atmospheric exposure, which is promising for practical applications in devices. Given the broad applicability of this simple combinatorial approach, it may impact many fields of (opto)electronics.

Cost-Effectiveness of Empirical Bismuth-Based Quadruple Therapy and Tailored Therapy After Clarithromycin Resistance Tests for Helicobacter pylori Eradication.

BACKGROUND: The eradication rate of clarithromycin-based standard triple therapy (STT) for Helicobacter pylori infection has decreased due to clarithromycin resistance (CR). We evaluated the cost-effectiveness of tailored therapy according to CR test results, and compared the results of STT with those of empirical bismuth quadruple therapy (BQT). METHODS: The prospectively collected data of 490 H. pylori-positive patients with chronic gastritis or peptic ulcer disease were retrospectively analyzed. Among them, 292 patients underwent CR testing using dual-priming oligonucleotide-based polymerase chain reaction. The tailored group (n = 292) consisted of patients treated with STT for 7 days and BQT for 10 days as per their CR test results. The remaining patients were assigned to the empirical group (n = 198) and received BQT for 10 days without a CR test. The eradication rate, adverse events and medical costs associated with H. pylori eradication therapy were investigated. RESULTS: In the tested patients (tailored group), the CR-positive rate was 32.2% (n = 94/292). The eradication rate according to an intention-to-treat analysis was 87.7% in the tailored group and 91.8% in the empirical group (P = 0.124); the respective rates were 94.4% and 97.9% by per-protocol analysis (P = 0.010). The frequency of adverse events was lower in the empirical group than the tailored group (35.1% vs. 52.7%, P < 0.001). Total per capita medical costs were $406.50 and $503.50, respectively. CONCLUSIONS: Ten-day empirical BQT was more effective, safer, and less expensive than tailored therapy based on a CR test for H. pylori eradication.

Long-term outcomes of endoscopic resection followed by additional surgery after non-curative resection in undifferentiated-type early gastric cancer: a nationwide multi-center study.

BACKGROUND: Undifferentiated-type early gastric cancer (UD EGC) shows lower curative resection rates after endoscopic submucosal dissection (ESD). Additional surgery is recommended after non-curative resection. We evaluated the long-term outcomes of ESD followed by additional surgery after non-curative resection in UD EGC compared to those for surgery as initial treatment. METHODS: We reviewed 1139 UD EGC patients who underwent ESD at 18 hospitals and 1956 patients who underwent surgery at two hospitals between February 2005 and May 2015. We enrolled 636 patients with non-curative ESD and 1429 surgery subjects beyond the curative ESD criteria. Among them, 133 patients with additional surgery after ESD (ESD + OP group) and 252 patients without additional surgery (ESD-only group) were matched 1:1 using propensity scores to patients with surgery as initial treatment (surgery group). Overall survival (OS) and recurrence-free survival (RFS) were compared. RESULTS: Signet ring cell carcinoma and poorly differentiated adenocarcinoma (PDA) were observed in 939 and 1126 cases, respectively. OS was significantly longer in the surgery group than in the ESD + OP group, especially for PDA. However, RFS was shorter in the ESD-only group than those in the ESD + OP and surgery groups. RFS did not differ significantly between the ESD + OP and surgery groups. Compared to the surgery group, the ESD-only and ESD + OP groups had an overall hazard ratio for RFS of 3.58 (95% confidence interval 1.44-8.88) and 0.46 (0.10-2.20), respectively. CONCLUSIONS: ESD followed by additional surgery after non-curative resection showed comparable cancer-specific outcomes to initial surgery in UD EGC.

Prediction model for curative endoscopic submucosal dissection of undifferentiated-type early gastric cancer.

BACKGROUND: Endoscopic submucosal dissection (ESD) is an effective treatment for early gastric cancer (EGC); however, its curative resection rate is low for undifferentiated-type EGC. We developed and externally validated a prediction model for curative ESD of undifferentiated-type EGC. METHODS: In this cross-sectional study, we included 448 patients who underwent ESD for undifferentiated-type EGC at 18 hospitals in Korea between 2005 and 2015 in the development cohort and 1342 patients who underwent surgery at two hospitals in the validation cohort. A prediction model was developed using the logistic regression model. RESULTS: Endoscopic tumor size 1-2 cm (odds ratio [OR], 2.40; 95% confidence interval [CI] 1.54-3.73), tumor size > 2 cm (OR, 14.00; 95% CI 6.81-28.77), and proximal tumor location from the lower to upper third of the stomach (OR, 1.45; 95% CI 1.03-2.04) were independent predictors of non-curative ESD. A six-score prediction model was developed by assigning points to endoscopic tumor size > 2 cm (five points), tumor size 1-2 cm (two points), upper third location (two points), and middle third location (one point). The rate of curative ESD ranged from 70.6% (score 0) to 11.6% (score 5) with an area under the receiver operating characteristic curve (AUC) of 0.720 (95% CI 0.673-0.766). The model also showed good performance in the validation cohort (AUC, 0.775; 95% CI 0.748-0.803). CONCLUSIONS: This six-score prediction model may help in predicting curative ESD and making informed decisions about the treatment selection between ESD and surgery for undifferentiated-type EGC.

Safety of Gastrointestinal Endoscopy in Korea: A Nationwide Survey and Population-Based Study.

BACKGROUND: Attention should be paid to endoscopy-related complications and safety-related accidents that may occur in the endoscopy unit. This study investigated the current status of complications associated with diagnostic and therapeutic endoscopy in Korea. METHODS: A questionnaire survey on endoscopy-related complications was conducted in a total of 50 tertiary or general hospitals in Korea. The results were compared to the population-level claims data from the Health Insurance Review & Assessment Service (HIRA), which analyzed endoscopy procedures conducted in 2017 in Korea. RESULTS: The incidences of bleeding associated with diagnostic and therapeutic esophagogastroduodenoscopy (EGD) and with diagnostic and therapeutic colonoscopy were 0.224% and 3.155% and 0.198% and 0.356%, respectively, in the 2017 HIRA claims data, compared to 0.012% and 1.857%, and 0.024% and 0.717%, in the 50 hospitals surveyed. The incidences of perforation associated with diagnostic and therapeutic EGD and with diagnostic and therapeutic colonoscopy were 0.023% and 0.613%, and 0.007% and 0.013%, respectively, in the 2017 HIRA claims data compared to 0.001% and 0.325%, and 0.017% and 0.206%, in the 50 hospitals surveyed. In the HIRA claims data, the incidence of bleeding/perforation after diagnostic colonoscopy in clinics, community hospitals, general hospitals, and tertiary hospitals was 0.129%/0.000%, 0.088%/0.004%, 0.262%/0.009%, and 0.479%/0.030% respectively, and the corresponding incidence of bleeding/perforation after therapeutic colonoscopy was 0.258%/0.004%, 0.401%/0.007%, 0.408%/0.024%, and 0.731%/0.055%. CONCLUSION: The incidences of complications associated with diagnostic and therapeutic EGD or colonoscopy tended to increase with the hospital volume in Korea. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0001728.

Risk factors of lymph node metastasis after non-curative endoscopic resection of undifferentiated-type early gastric cancer.

BACKGROUND: This study aimed to investigate risk factors for lymph node (LN) or distant metastasis after non-curative endoscopic resection (ER) of undifferentiated-type early gastric cancer (EGC). METHODS: Of 1124 patients who underwent ER for undifferentiated-type gastric cancer at 18 tertiary hospitals across six geographic areas in Korea between 2005 and 2014, 634 with non-curative ER beyond the expanded criteria were retrospectively enrolled. According to the treatment after ER, patients were divided into additional surgery (n = 270) and follow-up (n = 364) groups. The median follow-up duration was 59 months for recurrence and 84 months for mortality. RESULTS: LN metastasis was found in 6.7% (18/270) of patients at surgery. Ulcer [odds ratio (OR) 3.83; 95% confidence interval (CI) 1.21-12.13; p = 0.022] and submucosal invasion (OR 10.35; 95% CI 1.35-79.48; p = 0.025) were independent risk factors. In the follow-up group, seven patients (1.9%) developed LN or distant recurrence. Ulcer [hazard ratio (HR) 7.60; 95% CI 1.39-35.74; p = 0.018], LVI (HR 6.80; 95% CI 1.07-42.99; p = 0.042), and positive vertical margin (HR 6.71; 95% CI 1.28-35.19; p = 0.024) were independent risk factors. In the overall cohort, LN metastasis rates were 9.6% in patients with two or more risk factors and 1.2% in those with no or one risk factor. CONCLUSIONS: LVI, ulcer, submucosal invasion, and positive vertical margin are independently associated with LN or distant metastasis after non-curative ER of undifferentiated-type EGC. Surgical resection is strongly recommended for patients with two or more risk factors.

Clinical outcomes of endoscopic resection for undifferentiated intramucosal early gastric cancer larger than 2 cm.

BACKGROUND: This study investigated the long-term clinical outcomes of endoscopic resection (ER) for undifferentiated-type (UD) early gastric cancer (EGC), with tumor size > 2 cm as the only non-curative factor. METHODS: From among 1123 patients who underwent ER for UD EGC at 18 tertiary hospitals in Korea between 2005 and 2014, we identified 216 patients with UD intramucosal EGC > 2 cm, which was completely resected, with negative resection margins, and absence of ulceration and lymphovascular invasion. The patients were divided into the additional surgery (n = 40) or observation (n = 176) groups, according to post-ER management and were followed up for a median duration of 59 months for recurrence and 90 months for overall survival. RESULTS: Lymph node (LN) or distant metastasis or cancer-related mortality was not observed in the surgery group. In the observation group, two (1.1%) patients developed LN or distant metastasis with a 5-year cumulative risk of 0.7%, and one (0.6%) patient died of gastric cancer. The 5- and 8-year overall survival rates were 94.1% and 89.9%, respectively, in the observation group and 100.0% and 95.2%, respectively, in the surgery group (log-rank P = 0.159). Cox regression analysis did not reveal an association between the observation group and increased mortality. CONCLUSION: The risk of LN or distant metastasis was not negligible, but as low as 1% for patients undergoing non-curative ER for UD EGC, with tumor size > 2 cm as the only non-curative factor. Close observation may be an alternative to surgery, especially for older patients or those with poor physical status.

Comparison between endoscopic submucosal resection and surgery for the curative resection of undifferentiated-type early gastric cancer within expanded indications: a nationwide multi-center study.

BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) for undifferentiated early gastric cancer (UD EGC) has debate due to the risk of lymph node metastasis. We investigated the outcomes of ESD compared to those of surgery for the UD EGC within expanded indication. METHODS: We reviewed 971 UD EGC patients performed ESD across 18 hospitals in Korea and 1812 patients who underwent surgical resection in two hospitals between February 2005 and May 2015. Of these cases, we enrolled a curative resected ESD group of 328 patients and surgery group of 383 cases within an expanded indication. Overall outcomes and one-to-one propensity score-matched (218 ESD group vs 218 surgery group cases) outcomes for these two groups were analyzed. RESULTS: Over the 75.6 month median follow-up period for the 711 enrolled cases, recurrences occurred in 22 patients (6.7%) in the ESD group but not in the surgery group. Overall survival (OS) was higher in the surgery group (p = 0.0316) in all cases, but there was no significant difference after propensity score matching (p = 0.069). According to the histologic type in propensity score matching, the OS of signet ring cell carcinoma and poorly differentiated carcinoma patients did not differ between the ESD and surgery groups (p = 0.1189 and p = 0.3087, respectively). In the surgery group involving expanded criteria, lymph node metastasis was found in six cases (1.56%). CONCLUSIONS: Although ESD shows comparable outcomes to surgery for the UD EGC within expanded indications, appropriate patient selection is needed for the ESD due to the possibility of lymph node metastasis.

Computational Three-Dimensional Imaging System via Diffraction Grating Imaging with Multiple Wavelengths.

This paper describes a computational 3-D imaging system based on diffraction grating imaging with laser sources of multiple wavelengths. It was proven that a diffraction grating imaging system works well as a 3-D imaging system in our previous studies. The diffraction grating imaging system has advantages such as no spherical aberration and a low-cost system, compared with the well-known 3-D imaging systems based on a lens array or a camera array. However, a diffraction grating imaging system still suffers from noises, artifacts, and blurring due to the diffraction nature and illumination of single wavelength lasers. In this paper, we propose a diffraction grating imaging system with multiple wavelengths to overcome these problems. The proposed imaging system can produce multiple volumes through multiple laser illuminators with different wavelengths. Integration of these volumes can reduce noises, artifacts, and blurring in grating imaging since the original signals of 3-D objects inside these volumes are integrated by our computational reconstruction method. To apply the multiple wavelength system to a diffraction grating imaging system efficiently, we analyze the effects on the system parameters such as spatial periods and parallax angles for different wavelengths. A computational 3-D imaging system based on the analysis is proposed to enhance the image quality in diffraction grating imaging. Optical experiments with three-wavelength lasers are conducted to evaluate the proposed system. The results indicate that our diffraction grating imaging system is superior to the existing method.

Bipolar Membranes to Promote Formation of Tight Ice-Like Water for Efficient and Sustainable Water Splitting.

Bipolar membranes (BPMs) have recently received much attention for their potential to improve the water dissociation reaction (WDR) at their junction by utilizing catalysts. Herein, composite catalysts (Fe2 O3 @GO) comprising hematite nanoparticles (α-Fe2 O3 ) grown on 2D graphene oxide (GO) nanosheets are reported, which show unprecedentedly high water dissociation performance in the BPM. Furthermore, new catalytic roles in facilitating WDR at the catalyst-water interface are mechanistically elucidated. It is demonstrated that the partially dissociated bound water, formed by the strongly Lewis-acidic Fe atoms of the Fe2 O3 @GO catalyst, helps the "ice-like water" to become tighter, consequently resulting in weaker intramolecular OH bonds, which reduces activation barriers and thus significantly improves the WDR rate. Notably, Fe2 O3 @GO-incorporated BPM shows an extremely low water dissociation potential (0.89 V), compared to commercially available BPM (BP-1E, 1.13 V) at 100 mA cm-2 , and it is quite close to the theoretical potential required for WDR (0.83 V). This performance reduces the required electrical energy consumption for water splitting by ≈40%, as compared to monopolar (Nafion 212 and Selemion AMV) membranes. These results can provide a new approach for the development of water dissociation catalysts and BPMs for realizing highly efficient water splitting systems.

Narrowband imaging with near-focus magnification for discriminating the gastric tumor margin before endoscopic resection: A prospective randomized multicenter trial.

BACKGROUND AND AIM: This study investigated the usefulness of near-focus narrowband imaging (NF-NBI) for determining gastric tumor margins compared with indigo carmine chromoendoscopy (ICC) before endoscopic submucosal dissection (ESD). METHODS: This prospective randomized controlled trial was conducted at seven teaching hospitals in Korea. Patients with gastric adenoma or differentiated adenocarcinoma undergoing ESD were enrolled and randomly assigned to the NF-NBI or ICC group. A marking dot was placed on the most proximal margin of the tumor before ESD. The primary endpoint was delineation accuracy, which was defined as presence of marking dots within 1 mm of the tumor margin under microscopic observation. RESULTS: A total of 200 patients in the NF-NBI group and 195 patients in the ICC group were included. The delineation accuracy rate was 84.5% in the NF-NBI group and 81.0% in the ICC group (P = 0.44). However, the distance from the marking dot to the margin of the tumor was significantly shorter in the NF-NBI group than in the ICC group (0.8 ± 0.8 vs 1.2 ± 1.3 mm, P < 0.01). Even after adjustment of other clinicopathological factors that are associated with difficulty of tumor delineation, NF-NBI did not show significant association with accurate delineation (odds ratio of 0.86, P = 0.60). CONCLUSIONS: This prospective multicenter study showed that NF-NBI is not superior to ICC in terms of accurately delineating gastric tumors (NCT02661945).

Absolute laser ranging by time-of-flight measurement of ultrashort light pulses [Invited].

Ultrashort pulse lasers are emerging as an advanced tool of distance measurement, with their unique temporal and spectral characteristics being extended to diverse principles of absolute ranging and instrumentation. Here, a systematic methodology is presented for absolute ranging by means of the time-of-flight measurement of ultrashort light pulses using dual-comb asynchronous optical sampling. Based on an elaborate uncertainty analysis, influencing system parameters such as the pulse duration, repetition rate, and averaging time are optimized to achieve a sub-µm measurement accuracy. The absolute ranging system developed in this study demonstrates a combined standard uncertainty of 0.986 µm for a 0.5 ms averaging over a distance range of 3.0 m, with a further reduction to 0.056 µm when the averaging time is increased to 0.5 s. The outstanding performance leads to unprecedented multitarget applications: machine feed control with thermal error compensation in real time as well as the nondestructive inspection of multilens assembly in a production line.

Image Enhancement of Computational Reconstruction in Diffraction Grating Imaging Using Multiple Parallax Image Arrays.

This paper describes an image enhancement method of computational reconstruction for 3-D images with multiple parallax image arrays in diffraction grating imaging. A 3-D imaging system via a diffraction grating provides a parallax image array (PIA) which is a set of perspective images of 3-D objects. The parallax images obtained from diffraction grating imaging are free from optical aberrations such as spherical and chromatic aberrations that are always involved in the 3-D imaging via a lens array. The diffraction grating imaging system for 3-D imaging also can be made at a lower cost system than a camera array system. However, the parallax images suffer from the speckle noise due to a coherent source; also, the noise degrades image quality in 3-D imaging. To remedy this problem, we propose a 3-D computational reconstruction method based on multiple parallax image arrays which are acquired by moving a diffraction grating axially. The proposed method consists of a spatial filtering process for each PIA and an overlapping process. Additionally, we provide theoretical analyses through geometric and wave optics. Optical experiments are conducted to evaluate our method. The experimental results indicate that the proposed method is superior to the existing method in 3-D imaging using a diffraction grating.

Computational reconstruction for three-dimensional imaging via a diffraction grating.

This paper describes a computational reconstruction method for 3-D imaging via a diffraction grating. An optical device consisting of a diffraction grating with a camera produces a parallax image array (PIA) for 3-D imaging in an efficient way according to recent researches. Unlike other capturing systems for a PIA such as a lens array with a camera and a camera array, a diffraction grating with a camera has an advantage in terms of the optical system complexity. However, since the diffraction grating is transparent, the captured raw image by the diffraction grating has no feature to detect the boundary of each parallax image. Moreover, the diffraction grating allows parallax images to overlap each other due to its optical property. Those problems prevent computational reconstruction from generating 3-D images. To remedy those problems, we propose a 3-D computational reconstruction method via a diffraction grating. The proposed method using a diffraction grating includes analyzing the PIA pickup process and converting a captured raw image into a well-defined PIA. Our analysis introduces a virtual pinhole; thus, a diffraction grating works as a camera array. Also, it defines the effective object area to segment parallax images and provides a mapping between each segmented parallax image and corresponding virtual pinhole. The minimum image area is also defined to determine the minimum field of view for our reconstruction. Optical experimental results indicated the proposed theoretical analysis and computational reconstruction in diffraction grating imaging are feasible in 3-D imaging. To our best knowledge, this is the first report on 3-D computational reconstruction via a diffraction grating.

Clinicopathological characteristics of patients with pain after endoscopic submucosal dissection for gastric epithelial neoplasm.

BACKGROUND: Endoscopic submucosal dissection (ESD) is widely used for large superficial gastrointestinal tumors. Epigastric pain is a frequent complication of ESD. However, little is known about its incidence and associated factors. This study evaluated pain incidence and characteristics of patients with pain after gastric ESD. METHODS: We retrospectively analyzed a prospectively collected registry of clinical, endoscopic, and pathologic results of patients who underwent ESD for gastric adenoma or cancer from January 2010 to December 2015. A Visual Analogue Scale (VAS) was used to assess pain immediately after, and 2, 12, and 24 h after ESD. The primary outcome was the use of painkillers (VAS score > 4). Analyzed data included age, sex, pathology, specimen and tumor size, procedure time, and tumor location. RESULTS: Of 1226 patients, 461 (36.4%) needed a painkiller at least once after ESD (pain group). Compared with the no pain group, the pain group had more females, less alcohol consumption, larger tumor and specimen size, and more antral lesions. In multivariate analysis, female sex (OR 1.559, 95% CI 1.217-1.996, p < 0.001), antral tumor location (OR 1.780, 95% CI 1.398-2.265, p < 0.001), and procedure time over 30 min (OR 1.443, 95% CI 1.130-1.842, p = 0.003) were predictive factors for pain. CONCLUSION: This study showed that a considerable number of patients needed one or more painkiller doses after gastric ESD. The factors affecting pain included sex, procedure time, and lesion location. Endoscopists should use preemptive or aggressive pain management in high-risk patients after ESD.

The effect of surfactants on electrohydrodynamic jet printing and the performance of organic field-effect transistors.

In this article, we report on the direct writing of multi-walled carbon nanotube (MWCNT) composite inks based on three different surfactants via the electrohydrodynamic (EHD) jet printing technique. All three surfactants, including two types of polymeric surfactants and an ionic surfactant, successfully dispersed the MWCNTs in the ink medium. Although the MWCNT composite with the ionic surfactant could not be printed by the EHD process, the MWCNT composites with polymeric surfactants could be successfully printed using this technique. Furthermore, the printed lines exhibited different electrical and electronic characteristics, depending on the type of surfactant. A large amount of the poly(4-styrenesulfonic acid) (PSS) surfactant was required to disperse the MWCNTs in ethanol, whereas a smaller amount of polymeric Triton X-100 (TX100) was required to obtain a MWCNT composite suspension in distilled water, and therefore, the printed lines of the latter provided higher conductivities. In addition, the surface potential and charge carrier injection properties of the EHD-printed MWCNT lines depended on the type of surfactant in the MWCNT composite. Finally, organic field-effect transistors (OFETs) employing source/drain electrodes based on MWCNT/surfactant composites exhibited opposing electrical characteristics depending on the type of surfactant. The MWCNT/PSS lines showed excellent electrical performance when used as electrodes in p-type OFETs, whereas the MWCNT/TX100 lines exhibited excellent performance when used as electrodes in n-type OFETs.