Shorter interval to surgery after self-expanding metallic stent may result in better oncologic outcomes in colon cancer obstruction.

INTRODUCTION: Colon cancer obstruction is one of the most serious conditions in colorectal surgery. However, the use of self-expanding metallic stent (SEMS) has made it possible to avoid emergency surgery and stoma creation, therefore enabling minimally invasive surgery and one-stage operation. In this study, we aimed to investigate whether there is an optimal interval from SEMS to surgery for the best long-term oncologic outcomes. METHODS: Obstructive colon cancer patients treated with SEMS insertion and received surgery were included in the study. Patient data were retrospectively reviewed in prospectively collected data. Using the ROC curve, the optimal interval to surgery after SEMS insertion was 10 days; the patients were divided into the early surgery group (≤10 days, ES) and the late surgery group (>10 days, LS). Factors contributing to the 5-year disease-free survival (DFS) and overall survival (OS) were analyzed. RESULTS: 83 patients were included in this study. Eight patients (9.6 %) had SEMS insertion failure, with 3 perforations and 5 failed expansions. There were no differences between the ES group and the LS group in terms of pathologic characteristics, incidence of stoma creation, and adjuvant chemotherapy. Twenty-six patients (31.3 %) had recurrences; local (Arnarson et al., 2023) [6], peritoneal seeding (Lee et al., 2013) [8], liver (Ho et al., 2017) [11], lung [7], bone (van Hooft et al., 2020) [2], and abdominal wall metastasis (Chen and Sheen-Chen, 2000) [1]. The 5-year DFS rate was significantly better in the ES group than the LS group (74.3 % vs. 55.01 %; p = 0.0394). The 5-year OS was slightly better in the ES group than the LS group (76.11 % vs. 58.75 %; p = 0.0901). In univariable analysis, the ES group showed a lower risk of recurrence than the LS group (OR: 0.447 [0.204-0.984], p = 0.0455), but this was not reproduced in the multivariable analysis. CONCLUSION: This study has shown that the long-term oncologic outcomes were better in patients who received surgery after SEMS within 10 days. Hence, we propose with caution that elective surgery might be suggested to take place within 10 days from SEMS insertion for better oncologic outcomes.

Totally laparoscopic versus laparoscopy-assisted distal gastrectomy: the KLASS-07: a randomized controlled trial.

BACKGROUNDS: Strong evidence is lacking as no confirmatory randomized controlled trials (RCTs) have compared the efficacy of totally laparoscopic distal gastrectomy (TLDG) with laparoscopy-assisted distal gastrectomy (LADG). The authors performed an RCT to confirm if TLDG is different from LADG. METHODS: The KLASS-07 trial is a multi-centre, open-label, parallel-group, phase III, RCT of 442 patients with clinical stage I gastric cancer. Patients were enroled from 21 cancer care centres in South Korea between January 2018 and September 2020 and randomized to undergo TLDG or LADG using blocked randomization with a 1:1 allocation ratio, stratified by the participating investigators. Patients were treated through R0 resections by TLDG or LADG as the full analysis set of the KLASS-07 trial. The primary endpoint was morbidity within postoperative day 30, and the secondary endpoint was quality of life (QoL) for 1 year. This trial is registered at ClinicalTrials.gov (NCT03393182). RESULTS: Four hundred forty-two patients were randomized (222 to TLDG, 220 to LADG), and 422 patients were included in the pure analysis (213 and 209, respectively). The overall complication rate did not differ between the two groups (TLDG vs. LADG: 12.2% vs. 17.2%). However, TLDG provided less postoperative ileus and pulmonary complications than LADG (0.9% vs. 5.7%, P= 0.006; and 0.5% vs. 4.3%, P= 0.035, respectively). The QoL was better after TLDG than after LADG regarding emotional functioning at 6 months, pain at 3 months, anxiety at 3 and 6 months, and body image at 3 and 6 months (all P< 0.05). However, these QoL differences were resolved at 1 year. CONCLUSIONS: The KLASS-07 trial confirmed that TLDG is not different from LADG in terms of postoperative complications but has the advantages to reduce ileus and pulmonary complications. TLDG can be a good option to offer better QoL in terms of pain, body image, emotion, and anxiety at 3-6 months.

JOURNAL/ijos/04.03/01279778-202408000-00031/figure1/v/2024-08-13T152924Z/r/image-jpeg.

Nickel Oxide Hole Injection Layers for Balanced Charge Injection in Quantum Dot Light-Emitting Diodes.

Quantum dot (QD) light-emitting diodes (QLEDs) are promising for next-generation displays, but suffer from carrier imbalance arising from lower hole injection compared to electron injection. A defect engineering strategy is reported to tackle transport limitations in nickel oxide-based inorganic hole-injection layers (HILs) and find that hole injection is able to enhance in high-performance InP QLEDs using the newly designed material. Through optoelectronic simulations, how the electronic properties of NiOx affect hole injection efficiency into an InP QD layer, finding that efficient hole injection depends on lowering the hole injection barrier and enhancing the acceptor density of NiOx is explored. Li doping and oxygen enriching are identified as effective strategies to control intrinsic and extrinsic defects in NiOx, thereby increasing acceptor density, as evidenced by density functional theory calculations and experimental validation. With fine-tuned inorganic HIL, InP QLEDs exhibit a luminance of 45 200 cd m-2 and an external quantum efficiency of 19.9%, surpassing previous inorganic HIL-based QLEDs. This study provides a path to designing inorganic materials for more efficient and sustainable lighting and display technologies.

Nanoconfinement Enables Photoelectrochemical Selective Oxidation of Glycerol via the Microscale Fluid Effect.

The glycerol oxidation reaction (GOR) run with photoelectrochemical cells (PECs) is one of the most promising ways to upgrade biomass because it is thermodynamically favorable, while irreversible overoxidation leads to unsatisfactory product selectivities. Herein, a tunable one-dimensional nanoconfined environment was introduced into the GOR process, which accelerated mass transfer of glycerol via the microscale fluid effect and changed the main oxidation product from formic acid (FA) to glyceraldehyde (GLD), which led to retention of the heavier multicarbon products. The rate of glycerol diffusion in the nanochannels increased by a factor of 4.92 with decreasing inner diameters. The main product from the PEC-selective oxidation of glycerol changed from the C1 product FA to the C3 product GLD with a great selectivity of 60.7%. This work provides a favorable approach for inhibiting further oxidation of multicarbon products and illustrates the importance of microenvironmental regulation in biomass oxidation.

Near-strain-free anode architecture enabled by interfacial diffusion creep for initial-anode-free quasi-solid-state batteries.

Anode-free (or lithium-metal-free) batteries with garnet-type solid-state electrolytes are considered a promising path in the development of safe and high-energy-density batteries. However, their practical implementation has been hindered by the internal strain that arises from the repeated plating and stripping of lithium metal at the interlayer between the solid electrolyte and negative electrode. Herein, we utilize the titanium nitrate nanotube architecture and a silver-carbon interlayer to mitigate the anisotropic stress caused by the recurring formation of lithium deposition layers during the cycling process. The mixed ionic-electronic conducting nature of the titanium nitrate nanotubes effectively accommodates the entry of reduced Li into its free volume space via interfacial diffusion creep, achieving near-strain-free operation with nearly tenfold volume suppressing capability compared to a conventional Cu anode counterpart during the lithiation process. Notably, the fabricated Li6.4La3Zr1.7Ta0.3O12 (LLZTO)-based initial-anode-free quasi-solid-state battery full cell, coupled with an ionic liquid catholyte infused high voltage LiNi0.33Co0.33Mn0.33O2-based cathode with an areal capacity of 3.2 mA cm-2, exhibits remarkable room temperature (25 °C) cyclability of over 600 cycles at 1 mA cm-2 with an average coulombic efficiency of 99.8%.

Comparison between the mesenteric fixation method (MEFIX) and conventional methods at preventing the occurrence of Petersen's hernia: a study protocol for a multicenter randomized controlled trial.

BACKGROUND: Petersen's hernia, which occurs after Billroth-II (B-II) or Roux-en-Y (REY) anastomosis, can be reduced by defect closure. This study aims to compare the incidence of bowel obstruction above Clavien-Dindo classification grade III due to Petersen's hernia between the mesenteric fixation method and the conventional methods after laparoscopic or robotic gastrectomy. METHODS: This study was designed as prospective, single-blind, non-inferiority randomized controlled multicenter trial in Korea. Patients with histologically diagnosed gastric cancer of clinical stages I, II, or III who underwent B-II or REY anastomosis after laparoscopic or robotic gastrectomy are enrolled in this study. Participants who meet the inclusion criteria are randomly assigned to two groups: a CLOSURE group that underwent conventional Petersen's defect closure method and a MEFIX group that underwent the mesenteric fixation method. The primary endpoint is the number of patients who underwent surgery for bowel obstruction caused by Petersen's hernia within 3 years after laparoscopic or robotic gastrectomy. DISCUSSION: This trial is expected to provide high-level evidence showing that the MEFIX method can quickly and easily close Petersen's defect without increased postoperative complications compared to the conventional method. TRIAL REGISTRATION: ClinicalTrials.gov NCT05105360. Registered on November 3, 2021.

Heterogeneous Catalyst as a Functional Substrate Governing the Shape of Electrochemical Precipitates in Oxygen-Fueled Rechargeable Batteries.

Lithium-oxygen batteries have the potential to become the most eminent solution for future energy storage with their theoretical energy density exceeding all existing batteries. However, the insulating and insoluble discharge product (lithium peroxide; Li2O2) impairs practical application. Conventional catalyst designs based on the electronic structure and interfacial charge transfer descriptors have not been able to overcome these limitations due to Li2O2. Herein, we revisit the role of heterogeneous catalysts as substrates to regulate Li2O2 growth and the formation of solid/solid reaction interfaces. We demonstrate that controlled solid/solid interfacial structure design is a critical performance parameter beyond the inherent electronic structure. In particular, the Cu2O substrate in this study induces a homogeneous deposition of Pd atoms, which leads to well-controlled growth of Li2O2 resolving mass and charge transport limits (i.e., the bottleneck of oxygen reduction/evolution reactions), thus improving reversibility, capacity, and durability of the cells by dissipating electrochemical and mechanical stress. We thus verified the essential role of solid/solid interfaces to regulate the nucleation and growth process of Li2O2 in lithium-oxygen batteries.

Is 10 cm ileal resection sufficient in locally advanced caecal cancer surgery?

BACKGROUND: There is no consensus as to how much ileal resection is sufficient when performing a right hemicolectomy for right colon cancers. Locally advanced caecal cancer has the highest incidence of peri-ileal lymph node metastasis. Therefore, this study investigated whether the 10 cm ileum resection suggested by the Japanese Society for Cancer of the Colon and Rectum is oncologically safe in stage II and III caecal cancer. METHODS: The prospectively collected medical records of stage II and III caecal cancer patients who underwent a right hemicolectomy with at least D2 lymph node dissection were reviewed retrospectively. The patients were divided into two groups according to the length of proximal ileal resected: group 1 (≤10 cm) and group 2 (>10 cm). Factors contributing to the 5-year overall survival (OS) were analysed. RESULTS: The study enrolled 89 patients with pathological stage II or III caecal cancer. The >10 cm group tended to be younger (P = 0.0938) with higher pathological N stages (P = 0.0899) than the ≤10 cm group. The 5-year OS did not differ between the two groups. No significant difference was found between the two groups according to stage. Age (HR = 1.06, 95% CI = 1.02-1.10, P = 0.0069) and N2 stage (HR = 5.38, 95% CI = 1.90-15.28, P = 0.0016) were significantly associated with OS in both uni- and multivariate analyses. CONCLUSIONS: There was no OS benefit to resecting >10 cm of ileum in either stage II or III caecal cancer patients. Hence, we suggest that the '10 cm rule' is sufficient for stage II and III caecal cancer patients.

Doxifluridine versus Tegafur/Gimeracil/Oteracil (S-1) as adjuvant chemotherapy for patients with gastric cancer after gastrectomy: A propensity score-matched analysis.

INTRODUCTION: Doxifluridine (DF), an oral 5-FU prodrug, has been used for various solid cancers due to its efficacy and low toxicity. We aim to evaluate the effect of DF as adjuvant monotherapy in advanced gastric cancer. METHODS: We retrospectively reviewed the clinical data of 263 patients with advanced gastric cancer who underwent curative gastrectomy between January 2010 and December 2013 at our institute. Since previous randomized control trials have confirmed the efficacy of S-1 as adjuvant chemotherapy in advanced gastric cancer, we analyzed the oncologic effect and patient compliance of the DF group compared to the S-1 group. After propensity score matching, 48 patients were included in each group. RESULTS: There was no significant difference in 5-year overall survival (OS) and 5-year disease-free survival (DFS) between DF and S-1 groups (5-year OS; 77.1% vs 75.0%; p = 0.729, 5-year DFS; 76.6% vs 73.9%; p = 0.748). The completion rates of the DF and S-1 groups were 60.4% and 72.9%, respectively (p = 0.194). The mean relative dose intensity of the DF and S-1 groups were 76.2% and 84.2%, respectively (p = 0.195). After multivariate analysis, the chemotherapy regimen was not a risk factor for OS and DFS, whereas relative dose intensity and pathologic stage were independent prognostic factors. CONCLUSION: There was no significant difference in the oncologic effect and patient compliance between DF and S-1 groups. DF could be an alternative option for adjuvant chemotherapy in advanced gastric cancer. In addition, we confirmed that relative dose intensity is an important independent prognostic factor for survival.

Bifunctional Electron-Transporting Agent for Red Colloidal Quantum Dot Light-Emitting Diodes.

Indium phosphide (InP) quantum dots have enabled light-emitting diodes (LEDs) that are heavy-metal-free, narrow in emission linewidth, and physically flexible. However, ZnO/ZnMgO, the electron-transporting layer (ETL) in high-performance red InP/ZnSe/ZnS LEDs, suffers from high defect densities, quenches luminescence when deposited on InP, and induces performance degradation that arises due to trap migration from the ETL to the InP emitting layer. We posited that the formation of Zn2+ traps on the outer ZnS shell, combined with sulfur and oxygen vacancy migration between ZnO/ZnMgO and InP, may account for this issue. We synthesized therefore a bifunctional ETL (CNT2T, 3',3'″,3'″″-(1,3,5-triazine-2,4,6-triyl)tris(([1,1'-biphenyl]-3-carbonitrile)) designed to passivate Zn2+ traps locally and in situ and to prevent vacancy migration between layers: the backbone of the small molecule ETL contains a triazine electron-withdrawing unit to ensure sufficient electron mobility (6 × 10-4 cm2 V-1 s-1), and the star-shaped structure with multiple cyano groups provides effective passivation of the ZnS surface. We report as a result red InP LEDs having an EQE of 15% and a luminance of over 12,000 cd m-2; this represents a record among organic-ETL-based red InP LEDs.

Exploring ideal operative time for best outcomes in gastric cancer surgery: A multi-institutional study based on KLASS-07 database.

Objective: While a rushed operation can omit essential procedures, prolonged operative time results in higher morbidity. Nevertheless, the optimal operative time range remains uncertain. This study aimed to estimate the ideal operative time range and evaluate its applicability in laparoscopic cancer surgery. Methods: A prospectively collected multicenter database of 397 patients who underwent laparoscopic distal gastrectomy were retrospectively reviewed. The ideal operative time range was statistically calculated by separately analyzing the operative time of uneventful surgeries. Finally, intraoperative and postoperative outcomes were compared among the shorter, ideal, and longer operative time groups. Results: The statistically calculated ideal operative time was 135.4-165.4 min. The longer operative time (LOT) group had a lower rate of uneventful, perfect surgery than the ideal or shorter operative time (IOT/SOT) group (2.8% vs. 8.8% and 2.2% vs. 13.4%, all P<0.05). Longer operative time increased bleeding, postoperative morbidities, and delayed diet and discharge (all P<0.05). Particularly, an uneventful, perfect surgery could not be achieved when the operative time exceeded 240 min. Regardless of ideal time range, SOT group achieved the highest percentage of uneventful surgery (13.4%), which was possible by surgeon's ability to retrieve a higher number of lymph nodes and perform ≥150 gastrectomies annually. Conclusions: Operative time longer than the ideal time range (especially ≥240 min) should be avoided. If the essential operative procedure were faithfully conducted without compromising oncological safety, an operative time shorter than the ideal range leaded to a better prognosis. Efforts to minimize operative time should be attempted with sufficient surgical experience.

Dipole Engineering through the Orientation of Interface Molecules for Efficient InP Quantum Dot Light-Emitting Diodes.

InP-based quantum dot (QD) light-emitting diodes (QLEDs) provide a heavy-metal-free route to size-tuned LEDs having high efficiency. The stability of QLEDs may be enhanced by replacing organic hole-injection layers (HILs) with inorganic layers. However, inorganic HILs reported to date suffer from inefficient hole injection, the result of their shallow work functions. Here, we investigate the tuning of the work function of nickel oxide (NiOx) HILs using self-assembled molecules (SAMs). Density functional theory simulations and near-edge X-ray absorption fine structure put a particular focus onto the molecular orientation of the SAMs in tuning the work function of the NiOx HIL. We find that orientation plays an even stronger role than does the underlying molecular dipole itself: SAMs having the strongest electron-withdrawing nitro group (NO2), despite having a high intrinsic dipole, show limited work function tuning, something we assign to their orientation parallel to the NiOx surface. We further find that the NO2 group─which delocalizes electrons over the molecule by resonance─induces a deep lowest unoccupied molecular orbital level that accepts electrons from QDs, producing luminescence quenching. In contrast, SAMs containing a trifluoromethyl group exhibit an angled orientation relative to the NiOx surface, better activating hole injection into the active layer without inducing luminescence quenching. We report an external quantum efficiency (EQE) of 18.8%─the highest EQE among inorganic HIL-based QLEDs (including Cd-based QDs)─in InP QLEDs employing inorganic HILs.

Gravity and magnetic anomalies of earthquake-prone areas in the southwestern Ulleung basin margin, East Sea (Sea of Japan).

Submarine earthquakes have increased in the southwestern Ulleung Basin adjacent to the Korean Peninsula. This study analyzed the gravitational and magnetic properties of the three earthquake-prone areas (Hupo Bank and offshore regions near Pohang and Ulsan) in the basin. The basin was affected by tensile and compressive stresses during the formation of the East Sea. The southern Hupo Bank and the Pohang offshore exhibited high gravity anomalies and strong magnetic anomalies. Hupo Bank was separated from the peninsula and earthquakes in this region have been influenced by crustal fractures that facilitated igneous activities during the formation of the basin. Dense volcanic rocks and seaward dipping reflectors along the Pohang coast and continental slope suggest magmatic activities during the formation of the East Sea. Comparatively, the Ulsan offshore, with a thick sedimentary layer, exhibited a slightly higher gravity anomaly than the surrounding area, but no significant differences in the magnetic anomaly. Sequential tensile and compressive stresses related to the creation of the basin produced complex tectonic structures in this region. The magnetic tilt derivative results suggest that earthquakes were located near magnetic source boundaries. The results show that it is important to monitor earthquake-prone areas with gravity and magnetic anomalies.

Comparison between oxaliplatin therapy and capecitabine monotherapy for high-risk stage II - III elderly patients with colon cancer.

PURPOSE: 45% of colon cancer patients are elderly, yet they are often deviated from standard cancer management. The MOSAIC trial favored FOLFOX over FL with superior oncologic outcomes; however, which regimen is most beneficial in elderly population remains unclear. This study aimed to compare the efficacy of oxaliplatin-added chemotherapy and capecitabine monotherapy in high-risk stage II/stage III elderly colon cancer patients. METHODS: Colon cancer patients ≥70 years of age who received adjuvant chemotherapy at Inje University Busan Paik Hospital between February 2009 to April 2016 were included. Patients were separated into the oxaliplatin-added group and capecitabine monotherapy group. The primary outcomes were CSS and OS. RESULTS: Of 74 patients, 45 received oxaliplatin-added chemotherapy and 29 received capecitabine monotherapy. There was no difference between the two groups in CSS or OS (p = 0.9670 and p = 0.6801, respectively). The N stage was significantly associated with CSS in both uni/multivariate analysis (p = 0.0565 and p = 0.0347, respectively). The oxaliplatin-added group had more stage III patients, so we performed a subgroup analysis of CSS and OS based on stage, which also showed no significant difference. CONCLUSIONS: Capecitabine monotherapy is an oncologically safe regimen compared to oxaliplatin-added regimens in elderly patients with high-risk stage II/stage III colon cancer.

Magnitude and nucleation time of the 2017 Pohang Earthquake point to its predictable artificial triggering.

A damaging Mw5.5 earthquake occurred at Pohang, South Korea, in 2017, after stimulating an enhanced geothermal system by borehole fluid injections. The earthquake was likely triggered by these operations. Current approaches for predicting maximum induced earthquake magnitude ([Formula: see text]) consider the volume of the injected fluid as the main controlling factor. However, these approaches are unsuccessful in predicting earthquakes, such as the Pohang one. Here we analyse the case histories of induced earthquakes, and find that [Formula: see text] scales with the logarithm of the elapsed time from the beginning of the fluid injection to the earthquake occurrence. This is also the case for the Pohang Earthquake. Its significant probability was predictable. These results validate an alternative to predicting [Formula: see text]. It is to monitor the exceedance probability of an assumed [Formula: see text] in real time by monitoring the seismogenic index, a quantity that characterizes the intensity of the fluid-induced seismicity per unit injected volume.

Disordered-Layer-Mediated Reverse Metal-Oxide Interactions for Enhanced Photocatalytic Water Splitting.

In heterogeneous catalysts, metal-oxide interactions occur spontaneously but often in an undesired way leading to the oxidation of metal nanoparticles. Manipulating such interactions to produce highly active surface of metal nanoparticles can warrant the optimal catalytic activity but has not been established to date. Here we report that a prior reduced TiO2 support can reverse the interaction with Pt nanoparticles and augment the metallic state of Pt, exhibiting a 3-fold increase in hydrogen production rate compared to that of conventional Pt/TiO2. Spatially resolved electron energy loss spectroscopy of the Ti valence state and the electron density distribution within Pt nanoparticles provide direct evidence supporting that the Pt/TiO2/H2O triple junctions are the most active catalytic sites for water reduction. Our reverse metal-oxide interaction scheme provides a breakthrough in the stagnated hydrogen production efficiency and can be applied to other heterogeneous catalyst systems composed of metal nanoparticles with reducible oxide supports.

Comparing short-term outcomes after totally laparoscopic distal gastrectomy and laparoscopy-assisted distal gastrectomy with Billroth I anastomosis: early experience of a single institution.

Purpose: To determine the safety and feasibility of totally laparoscopic distal gastrectomy (TLDG) with modified delta-shaped anastomosis, we compared the short-term outcomes of TLDG to those of laparoscopy-assisted distal gastrectomy (LADG) with Billroth I anastomosis. Methods: We analyzed the characteristics of 85 patients with gastric cancer who underwent laparoscopic distal gastrectomy with Billroth I anastomosis between January 2013 and December 2018. After propensity score matching, each group had 35 patients. Results: Of these 85 patients, 44 underwent TLDG and 41 underwent LADG. Propensity score matching was performed with three covariates (age, underlying disease, and hypertension), and 35 patients from each group were matched 11. After matching, the TLDG group was older than the LADG group (64.5 ± 10.6 years vs. 56.3 ± 11.2 years, p = 0.003) and had more patients with hypertension (57.1% vs. 22.9%, p = 0.003). Tumors were larger in the TLDG group than in the LADG group (23.4 ± 16.2 mm vs. 16.0 ± 7.9 mm, p = 0.018). A greater proportion of patients had fever in the TLDG group than the LADG group (42.9% vs. 20.0%, p = 0.039), and C-reactive protein from postoperative days 3 to 6 was greater in the TLDG group (11.4 ± 5.7 mg/dL vs. 7.0 ± 5.0 mg/dL, p = 0.001). Conclusion: Although our data represent only our early experience performing TLDG with modified delta-shaped anastomosis, this procedure is relatively safe and feasible. Nevertheless, compared to LADG, which is the conventional method, the operative time for TLDG was longer. Surgeons must also watch out for anastomotic complications.

Efficient and stable blue quantum dot light-emitting diode.

The visualization of accurate colour information using quantum dots has been explored for decades, and commercial products employing environmentally friendly materials are currently available as backlights1. However, next-generation electroluminescent displays based on quantum dots require the development of an efficient and stable cadmium-free blue-light-emitting device, which has remained a challenge because of the inferior photophysical properties of blue-light-emitting materials2,3. Here we present the synthesis of ZnSe-based blue-light-emitting quantum dots with a quantum yield of unity. We found that hydrofluoric acid and zinc chloride additives are effective at enhancing luminescence efficiency by eliminating stacking faults in the ZnSe crystalline structure. In addition, chloride passivation through liquid or solid ligand exchange leads to slow radiative recombination, high thermal stability and efficient charge-transport properties. We constructed double quantum dot emitting layers with gradient chloride content in a light-emitting diode to facilitate hole transport, and the resulting device showed an efficiency at the theoretical limit, high brightness and long operational lifetime. We anticipate that our efficient and stable blue quantum dot light-emitting devices can facilitate the development of electroluminescent full-colour displays using quantum dots.

Effective time- and frequency-domain techniques for interpreting seismic precursors in groundwater level fluctuations on Jeju Island, Korea.

An effective method, involving time and frequency domains was developed to interpret seismic precursors by comparing groundwater-level fluctuations recorded immediately and long before the occurrence of a known earthquake. The proposed method, consisting of the pre-processing (3-point filtering, band-pass filtering, and spectrum analysis) and post-processing (weighted moving average method and histogram and spectrum analyses) stages, was applied to the groundwater-level time series measured at three monitoring wells on Jeju Island, South Korea, from 00:00 on 8 September 2016 to 00:00 on 22 September 2016. The Gyeongju earthquake (Mw 5.4) occurred at 20:32 on 12 September2016. The histogram analysis exhibited an accentuating bellshape as the total number of waveforms, including those caused by the earthquake, of the groundwater-level fluctuations increased. The weighted moving average analysis indicated that various abnormal waveforms with different periods occurred in the fluctuations approaching the occurrence of the earthquake. The periods of seismic precursors in the groundwater-level fluctuations were determined by spectrum analysis and varied among the monitoring wells. Seismic precursor responses attributable to the Gyeongju earthquake were identified at least 8 hours before the earthquake, and the method used in this study indicates its good potential to predict an impending earthquake.