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"Kim, Seung-Hyun"
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Flexible Cu2ZnSn(S,Se)4 solar cells with over 10% efficiency and methods of enlarging the cell area
For kesterite copper zinc tin sulfide/selenide (CZTSSe) solar cells to enter the market, in addition to efficiency improvements, the technological capability to produce flexible and large-area modules with homogeneous properties is necessary. Here, we report a greater than 10% efficiency for a cell area of approximately 0.5 cm
2
and a greater than 8% efficiency for a cell area larger than 2 cm
2
of certified flexible CZTSSe solar cells. By designing a thin and multi-layered precursor structure, the formation of defects and defect clusters, particularly tin-related donor defects, is controlled, and the open circuit voltage value is enhanced. Using statistical analysis, we verify that the cell-to-cell and within-cell uniformity characteristics are improved. This study reports the highest efficiency so far for flexible CZTSSe solar cells with small and large areas. These results also present methods for improving the efficiency and enlarging the cell area.
Flexibility and homogeneity are preferred properties for the kesterite solar modules to compete with silicon counterparts. Here, Yang et al. achieve these properties by designing a thin and multi-layered precursor structure and at the same time increase the open circuit voltage and device efficiency.
Journal Article
Biological function of eosinophil extracellular traps in patients with severe eosinophilic asthma
Eosinophil extracellular traps (EETs), a complex of DNA fibers and cytotoxic granule proteins, are implicated in the development of asthma; however, the pathophysiological function of EETs in immune responses has not been fully determined. The present study investigated the characteristics of EETs from patients with non-severe asthma (NSA,
n
= 20) and severe eosinophilic asthma (SEA,
n
= 20) and evaluated EET function. The percentage of EET-forming peripheral blood eosinophils stimulated with IL-5 and LPS was significantly higher in patients with SEA than in those with NSA
(P
= 0.009). This percentage negatively correlated with baseline FEV
1
(
r
= −0.350,
P
= 0.027) and positively correlated with serum eosinophil-derived neurotoxin levels in asthmatic subjects (
r
= 0.437,
P
= 0.018). In addition, EET formation was markedly associated with reactive oxygen species production (
r
= 0.750,
P
<
0.001). These EETs exhibited an autocrine function to induce eosinophil degranulation, which led to granule protein production. Airway epithelial cells stimulated with EETs exhibited increased epithelial detachment and permeability and pro-inflammatory cytokine release. However, EETs were not significantly associated with mast cell activation. The present study suggests that peripheral blood eosinophils from patients with SEA may be more activated to produce EETs than those from patients with NSA, which further induces inflammation in asthmatic airways. Therefore, regulation of EET formation and function may be a novel therapeutic approach for asthma management.
Asthma: Traps to target for treatment
Controlling the formation of mesh-like structures of DNA and protein which induce airway damage in asthma could offer new therapeutic opportunities, especially for patients who do not respond well to conventional treatments. The structures are produced by activated cells as part of the immune response in asthma. They are known as eosinophil extracellular traps (EETs) since they are most prominently released by the activity of white blood cells called eosinophils. Hae-Sim Park and colleagues at Ajou University in South Korea studied the involvement of EETs in patients with severe asthma. Their results suggest eosinophils are more activated to create damaging EETs in patients with severe asthma than in those with less severe forms of the disease. Searching for ways to control EET formation could be a fruitful approach to helping patients with severe eosinophilic asthma.
Journal Article
Synergistic enhancement of AAV gene delivery in 2D cells and 3D organoids using polybrene and hydroxychloroquine
Recent advances in three-dimensional (3D) culture platforms have enabled organoids to serve as physiologically relevant models for recapitulating human biology and assessing therapeutic efficacy and toxicity. Despite their promise, their complex architecture presents significant challenges for efficient gene delivery, thereby limiting their broader application in drug discovery and translational research. To overcome this challenge, we developed a sequential treatment strategy that combines polybrene (PB), which facilitates viral entry, and hydroxychloroquine (HCQ), which modulates endosomal processing. By applying PB as a pre-treatment and HCQ as a post-treatment, we achieved an approximate 1.3- to 2-fold increase in adeno-associated virus (AAV) transduction efficiency in both retinal and liver organoid models compared to single-agent treatments, and a 1.7- to 2.5-fold increases compared to treatment with virus alone. Importantly, this combinatorial treatment preserved cellular integrity, as confirmed by minimal TUNEL assay and high overall viability. Our findings demonstrate that sequential administration of PB and HCQ significantly improves AAV transduction in 3D retinal and liver organoid systems, offering a robust method to improve gene delivery. This approach not only overcomes current limitations in organoid-based research but also supports the development of more predictive platforms for evaluating AAV vectors and advancing gene therapy applications.
Journal Article
Comparative Study on Seed Characteristics, Antioxidant Activity, and Total Phenolic and Flavonoid Contents in Accessions of Sorghum bicolor (L.) Moench
Sorghum is a major cereal food worldwide, and is considered a potential source of minerals and bioactive compounds. Its wide adaptive range may cause variations in its agronomic traits, antioxidant properties, and phytochemical content. This extensive study investigated variations in seed characteristics, antioxidant properties, and total phenolic (TPC) and flavonoid contents (TFC) of sorghum collected from different ecological regions of 15 countries. The antioxidant potential of the seed extracts of various sorghum accessions was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis 3-ethylbenzothiazoline-6-sulfonate (ABTS) radical scavenging assays. Significant variations in TPC were observed among the sorghum accessions. All 78 sorghum accessions used in this study exhibited significant variations in TFC, with the lowest and highest amount observed in accessions C465 and J542, respectively. DPPH scavenging potential of the seed extracts for all the accessions ranged from 11.91 ± 4.83 to 1343.90 ± 81.02 µg mL−1. The ABTS assay results were similar to those of DPPH but showed some differences in the accessions. Pearson’s correlation analysis revealed a wide variation range in the correlation between antioxidant activity and TPC, as well as TFC, among the sorghum accessions. A wide diversity range was also recorded for the seed characteristics (1000-seed weight and seed germination rate). A dendrogram generated from UPGMA clustering, based on seed traits, antioxidant activity, TPC, and TFC was highly dispersed for these accessions. Variations among the accessions may provide useful information regarding the phytoconstituents, antioxidant properties, and phytochemical contents of sorghum and aid in designing breeding programs to obtain sorghum with improved agronomic traits and bioactive properties.
Journal Article
Application of Light-Emitting Diodes for Improving the Nutritional Quality and Bioactive Compound Levels of Some Crops and Medicinal Plants
Light is a key factor that affects phytochemical synthesis and accumulation in plants. Due to limitations of the environment or cultivated land, there is an urgent need to develop indoor cultivation systems to obtain higher yields with increased phytochemical concentrations using convenient light sources. Light-emitting diodes (LEDs) have several advantages, including consumption of lesser power, longer half-life, higher efficacy, and wider variation in the spectral wavelength than traditional light sources; therefore, these devices are preferred for in vitro culture and indoor plant growth. Moreover, LED irradiation of seedlings enhances plant biomass, nutrient and secondary metabolite levels, and antioxidant properties. Specifically, red and blue LED irradiation exerts strong effects on photosynthesis, stomatal functioning, phototropism, photomorphogenesis, and photosynthetic pigment levels. Additionally, ex vitro plantlet development and acclimatization can be enhanced by regulating the spectral properties of LEDs. Applying an appropriate LED spectral wavelength significantly increases antioxidant enzyme activity in plants, thereby enhancing the cell defense system and providing protection from oxidative damage. Since different plant species respond differently to lighting in the cultivation environment, it is necessary to evaluate specific wavebands before large-scale LED application for controlled in vitro plant growth. This review focuses on the most recent advances and applications of LEDs for in vitro culture organogenesis. The mechanisms underlying the production of different phytochemicals, including phenolics, flavonoids, carotenoids, anthocyanins, and antioxidant enzymes, have also been discussed.
Journal Article
Changes in Soybean (Glycine max L.) Flour Fatty-Acid Content Based on Storage Temperature and Duration
Soybeans are low in saturated fat and a rich source of protein, dietary fiber, and isoflavone; however, their nutritional shelf life is yet to be established. This study evaluated the change in the stability and quality of fatty acids in raw and roasted soybean flour under different storage temperatures and durations. In both types of soybean flour, the fatty-acid content was the highest in the order of linoleic acid (18-carbon chain with two double bonds; C18:2), oleic acid (C18:1), palmitic acid (C16:0), linolenic acid (18:3), and stearic acid (C18:0), which represented 47%, 26%, 12%, 9%, and 4% of the total fatty-acid content, respectively. The major unsaturated fatty acids of raw soybean flour—oleic acid, linoleic acid, and linolenic acid—decreased by 30.0%, 94.4%, and 97.7%, and 38.0%, 94.8%, and 98.0% when stored in polyethylene and polypropylene film, respectively, after 48 weeks of storage under high-temperature conditions. These values were later increased due to hydrolysis. This study presents the changes in composition and content of two soybean flour types and the changes in quality and stability of fatty acids in response to storage temperature and duration. This study shows the influence of storage conditions and temperature on the nutritional quality which is least affected by packing material.
Journal Article
Face Biometric Spoof Detection Method Using a Remote Photoplethysmography Signal
Spoofing attacks in face recognition systems are easy because faces are always exposed. Various remote photoplethysmography-based methods to detect face spoofing have been developed. However, they are vulnerable to replay attacks. In this study, we propose a remote photoplethysmography-based face recognition spoofing detection method that minimizes the susceptibility to certain database dependencies and high-quality replay attacks without additional devices. The proposed method has the following advantages. First, because only an RGB camera is used to detect spoofing attacks, the proposed method is highly usable in various mobile environments. Second, solutions are incorporated in the method to obviate new attack scenarios that have not been previously dealt with. In this study, we propose a remote photoplethysmography-based face recognition spoofing detection method that improves susceptibility to certain database dependencies and high-quality replay attack, which are the limitations of previous methods without additional devices. In the experiment, we also verified the cut-off attack scenario in the jaw and cheek area where the proposed method can be counter-attacked. By using the time series feature and the frequency feature of the remote photoplethysmography signal, it was confirmed that the accuracy of spoof detection was 99.7424%.
Journal Article
Clinical factors affecting the rate of exodrift after surgery in patients with basic intermittent exotropia
We investigated the period of postoperative exodrift during follow-up and clinical factors that affect the rate of exodrift after surgery in the patients with intermittent exotropia (IXT). A retrospective review of medical records of patients with exodrift who underwent bilateral rectus recession for IXT was performed. Exodrift was defined as angle of deviation greater than 10 prism diopters (PD) at distance and near. The median survival period of postoperative exodrift was analyzed using Kaplan Meier survival analysis. The patients were divided into two groups according to the median period of postoperative exodrift (early and late group). The weighted Cox’s proportional hazards regression analysis to investigate the risk factors that affect rate of postoperative exodrift was performed. A total of 108 patients was included. The preoperative angle of deviation at distance and near were 30.3 ± 7.2 PD and 29.5 ± 8.6 PD, respectively. The median survival period of postoperative exodrift was 24 months (range, 6–48 months).The angle of deviation at postoperative day 1 in early and late group were − 3.8 ± 5.5 PD (range, − 16–8 PD) and − 7.7 ± 4.6 PD (range, − 16–4 PD) (
p
< 0.01). Minus value means esodeviation. In regression analysis, the angle of deviation at postoperative day 1 was the significantly related with rate of exodrift (
p
< 0.01). The median period of exodrift after surgery was 24 months, angle of deviation at postoperative day 1 could affect the rate of exodrift in patients with IXT.
Journal Article
An Economical Boil-Off Gas Management System for LNG Refueling Stations: Evaluation Using Scenario Analysis
The use of liquefied natural gas (LNG) in the transportation sector is increasing, and boil-off gas (BOG) management systems are considered viable options to increase economic efficiency and reduce greenhouse gas emissions at LNG refueling stations. The present study proposed an economically optimized method by investigating four refueling station scenarios, including different BOG management systems. Among the four scenarios, the scenario in which compressed natural gas was produced from BOG had the lowest minimum selling price (MSP) and was the most economical. Sensitivity and uncertainty analyses were conducted for the economically optimal scenario, which identified the factors with the most influential impact and their uncertainties on the MSP. Finally, to determine the feasibility of the business through profitability analysis, the net present value, discounted payback period, and present value ratio due to changes in the discount rate were presented, and the discounted cash flow rate of return was found to be 13.22%. As a result of this study, a BOG management system can contribute to improving the economic feasibility for LNG refueling stations by reliquefying BOG and re-selling it (the most efficient way is scenario 4) and will provide an economical guide for countries with much demand for LNG in the transport sector.
Journal Article