Highly stable semitransparent multilayer graphene/LaVO3vertical-heterostructure photodetectors.

A heterostructure composed of a combination of semi-metallic graphene (Gr) and high-absorption LaVO3is ideal for high-performance translucent photodetector (PD) applications. Here, we present multilayer Gr/LaVO3vertical-heterostructure semitransparent PDs with various layer numbers (Ln). AtLn= 2, the PD shows the best performance with a responsivity (R) of 0.094 A W-1and a specific detectivity (D*) of 7.385 × 107cm Hz1/2W-1at 532 nm. Additionally, the average visible transmittance of the PD is 63%, i.e. it is semitransparent. We increased photocurrent (PC) by approximately 13%, from 0.564 to 0.635µA cm-2by using an Al reflector on the semitransparent PD. The PC of an unencapsulated PD maintains about 86% (from 0.571 to 0.493µA cm-2) of its initial PC value after 2000 h at 25 °C temperature/30% relative humidity, showing good stability. This behavior is superior to that of previously reported graphene-based PDs. These results show that these PDs have great potential for semitransparent optoelectronic applications.

Estimation of Whole Plant Photosynthetic Rate of Irwin Mango under Artificial and Natural Lights Using a Three-Dimensional Plant Model and Ray-Tracing.

Photosynthesis is an important physiological response for determination of CO2 fertilization in greenhouses and estimation of crop growth. In order to estimate the whole plant photosynthetic rate, it is necessary to investigate how light interception by crops changes with environmental and morphological factors. The objectives of this study were to analyze plant light interception using a three-dimensional (3D) plant model and ray-tracing, determine the spatial distribution of the photosynthetic rate, and estimate the whole plant photosynthetic rate of Irwin mango (Mangifera indica L. cv. Irwin) grown in greenhouses. In the case of mangoes, it is difficult to measure actual light interception at the canopy level due to their vase shape. A two-year-old Irwin mango tree was used to measure the whole plant photosynthetic rate. Light interception and whole plant photosynthetic rate were measured under artificial and natural light conditions using a closed chamber (1 × 1 × 2 m). A 3D plant model was constructed and ray-tracing simulation was conducted for calculating the photosynthetic rate with a two-variable leaf photosynthetic rate model of the plant. Under artificial light, the estimated photosynthetic rate increased from 2.0 to 2.9 µmolCO2·m-2·s-1 with increasing CO2 concentration. On the other hand, under natural light, the photosynthetic rate increased from 0.2 µmolCO2·m-2·s-1 at 06:00 to a maximum of 7.3 µmolCO2·m-2·s-1 at 09:00, then gradually decreased to -1.0 µmolCO2·m-2·s-1 at 18:00. In validation, simulation results showed good agreement with measured results with R² = 0.79 and RMSE = 0.263. The results suggest that this method could accurately estimate the whole plant photosynthetic rate and be useful for pruning and adequate CO2 fertilization.

Semitransparent Solar Cells Employing n-Type Graphene on LaVO3.

To effectively utilize solar energy, semitransparent solar cells are essential in various fields such as building-integrated solar power generation and portable solar chargers. We report triethylenetetramine (TETA)-doped graphene (Gr) transparent conductive electrode (TCE)-based LaVO3 semitransparent solar cells. To optimize the Gr TCE, we varied the TETA molar concentration (nD) from 0.1 to 0.3 mM. TETA-doped Gr (TETA-Gr)/LaVO3 semitransparent solar cells exhibit the highest 1.45% efficiency and 62% average visible transmittance at nD = 0.2 mM. These results indicate that the TETA-Gr/LaVO3 structure not only harvests solar energy in the ultraviolet-visible region but also exhibits translucency, thanks to the thin film. Thanks to its translucent properties, we improved the power conversion efficiency (PCE) to 1.99% by adding an Al reflective mirror to the semitransparent cells. Finally, the device's PCE loss is only within 3% for 3000 h in air, suggesting good durability.

Colored LED Lights: Use One Color Alone or with Others for Growth in Hedyotis corymbosa In Vitro?

In recent years, light-emitting diode (LED) technology has been applied to improve crop production and induce targeted biochemical or physiological responses in plants. This study investigated the effect of different ratios of blue 450 nm and red 660 nm LEDs on the overall plant growth, photosynthetic characteristics, and total triterpenoid production in the leaves of Hedyotis corymbosa in vitro plants. The results showed that a high proportion of blue LED lights had a positive effect on enhancing photosynthesis and the overall biomass. In addition, blue LED lights were shown to be more effective in controlling the production of the total triterpenoid content compared with the red LED lights. Moreover, it was also found that plants grown under a high proportion of red LEDs exhibited reduced photosynthetic properties and even induced damage to the photosynthetic apparatus, which indicated that the blue or red LED lights played contrary roles in Hedyotis corymbosa.

Dielectrophoretic Manipulation of Janus Particle in Conductive Media for Biomedical Applications.

Janus particles are applied to many fields including biomedical applications. To expand the usability of Janus particles, a technique to manipulate the particle movement is required. A dielectrophoresis (DEP) method can be a promising candidate; however, independent manipulation or separation of Janus particle by DEP is still challenging. Additionally, DEP of Janus particles in conductive media is important especially for biomedical applications where ion-rich media are typically used. Here, the experimental results of DEP-induced transport and separation of the Janus particle in conductive media are presented. To predict the DEP behavior, the Clausius-Mossotti (CM) factors of both Janus and homogeneous particles are calculated, depending on the alternating current (AC) frequency and medium conductivity. The Janus particles show the positive-DEP behavior at the entire AC frequency region tested due to the metal-coated half surface. On the other hand, the homogeneous particles show the negative-DEP behavior at the high AC frequency or in conductive media. Additionally, in the conductive media, an electrohydrodynamic flow hinders the DEP-driven particle transport below MHz AC frequencies. Finally, the separation of the Janus particles from the homogeneous ones is experimentally demonstrated and the separation efficiency is discussed based on the evaluation parameters established in this study.

Prediction of Adverse Events in Stable Non-Variceal Gastrointestinal Bleeding Using Machine Learning.

Clinical risk-scoring systems are important for identifying patients with upper gastrointestinal bleeding (UGIB) who are at a high risk of hemodynamic instability. We developed an algorithm that predicts adverse events in patients with initially stable non-variceal UGIB using machine learning (ML). Using prospective observational registry, 1439 out of 3363 consecutive patients were enrolled. Primary outcomes included adverse events such as mortality, hypotension, and rebleeding within 7 days. Four machine learning algorithms, namely, logistic regression with regularization (LR), random forest classifier (RF), gradient boosting classifier (GB), and voting classifier (VC), were compared with the Glasgow-Blatchford score (GBS) and Rockall scores. The RF model showed the highest accuracies and significant improvement over conventional methods for predicting mortality (area under the curve: RF 0.917 vs. GBS 0.710), but the performance of the VC model was best in hypotension (VC 0.757 vs. GBS 0.668) and rebleeding within 7 days (VC 0.733 vs. GBS 0.694). Clinically significant variables including blood urea nitrogen, albumin, hemoglobin, platelet, prothrombin time, age, and lactate were identified by the global feature importance analysis. These results suggest that ML models will be useful early predictive tools for identifying high-risk patients with initially stable non-variceal UGIB admitted at an emergency department.

Alkaline Hydrolysis and Dyeing Characteristics of Sea-Island-Type Ultramicrofibers of PET Tricot Fabrics with Black Disperse Dye.

In this study, we investigated conditions for the alkaline hydrolysis and black-disperse dyeing of sea-island-type polyethylene terephthalate (PET) ultramicrofiber tricot fabric. We examined the weight loss ratios and tensile strengths according to the NaOH content (10%-30% on mass of fabric (omf)) during treatment; the optimal conditions used 25% omf NaOH for 30 min at 100 °C for an average weight loss ratio of 23.47%. By scanning electron microscope (SEM) analysis, the 'sea' components are extracted with increasing NaOH concentration until 25% omf NaOH, and damage of the 'island' components above 25% omf NaOH leads to a reduction in tensile strength. The dyeing conditions, including temperature (95-135 °C), time (20-60 min), pH buffer solution concentration (1-9 g/L), and contents of dispersant (1-9 g/L) and UV-absorbent (5%-25% omf) were also explored. The optimal dyeing conditions were established as a dye concentration of 8% omf with 1 g/L dispersant, 1 g/L pH buffer solution concentration, and 10% omf UV-absorbent at 135 °C for 40 min at a 1:10 goods-to-liquor ratio. The rubbing colorfastness values for the fabrics dyed with the black disperse dye spanned four grades under dry and wet conditions. The light colorfastness values of the dyed fabrics were good to excellent in the range of 4-5 grades.

Comparison of risk scores and shock index in hemodynamically stable patients presenting to the emergency department with nonvariceal upper gastrointestinal bleeding.

OBJECTIVE: Risk assessment in nonvariceal upper gastrointestinal bleeding (UGIB) is not well validated and remains unclear in hemodynamically stable patients at emergency department admission. We compared the prognostic value of risk-scoring systems for predicting adverse outcomes in patients with nonvariceal UGIB and normotension. PARTICIPANTS AND METHODS: A single-center prospective observational study was carried out. Patients with consecutive nonvariceal UGIB, presenting with normotension (systolic blood pressure ≥90 mmHg) to the emergency department, were included. We compared the areas under the curves (AUC) of Glasgow Blatchford score (GBS), the pre-endoscopy Rockall score, AIMS65, the shock index, and the modified shock index with respect to adverse outcomes defined as embolization, surgery, ICU admission, rebleeding, and in-hospital mortality. RESULTS: In total, 1233 patients were included. Adverse outcomes occurred in 165 (13.4%) patients; in-hospital mortality was 1.2%. AUC of the GBS for adverse outcome was higher than that of the shock index, but not significantly different (0.647 vs. 0.569, P=0.23). AUC values of the modified shock index, AIMS65, and the pre-endoscopy Rockall score were 0.565, 0.593, and 0.533, respectively. The cut-off value of the GBS (≥8) was associated with 85% sensitivity and 35% specificity for predicting adverse outcome. CONCLUSION: Pre-existing risk scores have shown suboptimal predictive ability for adverse events in normotensive patients with nonvariceal UGIB. The GBS (≥8) might help to identify patients prone to adverse events; however, further studies with risk scores or new scores are needed because of the low accuracy of these scores.

Early Risk Score for Predicting Hypotension in Normotensive Patients with Non-Variceal Upper Gastrointestinal Bleedin.

Risk assessment for upper gastrointestinal bleeding (UGIB) is important; however, current scoring systems are insufficient. We aimed to develop and validate a prediction model for rapidly determining the occurrence of hypotension in non-variceal UGIB patients with normotension (systolic blood pressure ≥90 mmHg) at emergency department presentation. In this prospective observational cohort study, consecutive non-variceal UGIB patients between January 2012 and April 2017 were enrolled. We developed and validated a new prediction model through logistic regression, with the occurrence of hypotension <24 h as the primary outcome. Among 3363 UGIB patients, 1439 non-variceal UGIB patients were included. The risk factors for the occurrence of hypotension were lactate level, blood in nasogastric tube, and systolic blood pressure. The area under the curve (AUC) of the new scoring model (LBS-Lactate, Blood in nasogastric tube, Systolic blood pressure) in the development cohort was 0.74, higher than the value of 0.64 of the Glasgow⁻Blatchford score for predicting the occurrence of hypotension. The AUC of the LBS score in the validation cohort was 0.83. An LBS score of ≤2 had a negative predictive value of 99.5% and an LBS score of ≥7 had a specificity of 97.5% in the validation cohort. The new LBS score stratifies normotensive patients with non-variceal UGIB at risk for developing hypotension.