Scalable CIGS Solar Cells Employing a New Device Design of Nontoxic Buffer Layer and Microgrid Electrode.

The efficiency of copper indium gallium selenide (CIGS) solar cells that use transparent conductive oxide (TCO) as the top electrode decreases significantly as the device area increases owing to the poor electrical properties of TCO. Therefore, high-efficiency, large-area CIGS solar cells require the development of a novel top electrode with high transmittance and conductivity. In this study, a microgrid/TCO hybrid electrode is designed to minimize the optical and resistive losses that may occur in the top electrode of a CIGS solar cell. In addition, the buffer layer of the CIGS solar cells is changed from the conventional CdS buffer to a dry-processed wide-band gap ZnMgO (ZMO) buffer, resulting in increased device efficiency by minimizing parasitic absorption in the short-wavelength region. By optimizing the combination of ZMO buffer and the microgrid/TCO hybrid electrode, a device efficiency of up to 20.5% (with antireflection layers) is achieved over a small device area of 5 mm × 5 mm (total area). Moreover, CIGS solar cells with an increased device area of up to 20 mm × 70 mm (total area) exhibit an efficiency of up to 19.7% (with antireflection layers) when a microgrid/TCO hybrid electrode is applied. Thus, this study demonstrates the potential for high-efficiency, large-area CIGS solar cells with novel microgrid electrodes.

A machine learning-based approach for predicting renal function recovery in general ward patients with acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) is a significant challenge in healthcare. While there are considerable researches dedicated to AKI patients, a crucial factor in their renal function recovery, is often overlooked. Thus, our study aims to address this issue through the development of a machine learning model to predict restoration of kidney function in patients with AKI. METHODS: Our study encompassed data from 350,345 cases, derived from three hospitals. AKI was classified in accordance with the Kidney Disease: Improving Global Outcomes. Criteria for recovery were established as either a 33% decrease in serum creatinine levels at AKI onset, which was initially employed for the diagnosis of AKI. We employed various machine learning models, selecting 43 pertinent features for analysis. RESULTS: Our analysis contained 7,041 and 2,929 patients' data from internal cohort and external cohort respectively. The Categorical Boosting Model demonstrated significant predictive accuracy, as evidenced by an internal area under the receiver operating characteristic (AUROC) of 0.7860, and an external AUROC score of 0.7316, thereby confirming its robustness in predictive performance. SHapley Additive exPlanations (SHAP) values were employed to explain key factors impacting recovery of renal function in AKI patients. CONCLUSION: This study presented a machine learning approach for predicting renal function recovery in patients with AKI. The model performance was assessed across distinct hospital settings, which revealed its efficacy. Although the model exhibited favorable outcomes, the necessity for further enhancements and the incorporation of more diverse datasets is imperative for its application in real- world.

Effects of the Electrical Properties of SnO2 and C60 on the Carrier Transport Characteristics of p-i-n-Structured Semitransparent Perovskite Solar Cells.

Recently, metal halide perovskite-based top cells have shown significant potential for use in inexpensive and high-performance tandem solar cells. In state-of-the-art p-i-n perovskite/Si tandem devices, atomic-layer-deposited SnO2 has been widely used as a buffer layer in the top cells because it enables conformal, pinhole-free, and highly transparent buffer layer formation. In this work, the effects of various electrical properties of SnO2 and C60 layers on the carrier transport characteristics and the performance of the final devices were investigated using a numerical simulation method, which was established based on real experimental data to increase the validity of the model. It was found that the band alignment at the SnO2/C60 interface does, indeed, have a significant impact on the electron transport. In addition, as a general design rule, it was suggested that at first, the conduction band offset (CBO) between C60 and SnO2 should be chosen so as not to be too negative. However, even in a case in which this CBO condition is not met, we would still have the means to improve the electron transport characteristics by increasing the doping density of at least one of the two layers of C60 and/or SnO2, which would enhance the built-in potential across the perovskite layer and the electron extraction at the C60/SnO2 interface.

Optical Characterization and Prediction with Neural Network Modeling of Various Stoichiometries of Perovskite Materials Using a Hyperregression Method.

Quaternary perovskite solar cells are being extensively studied, with the goal of increasing solar cell efficiency and securing stability by changing the ratios of methylammonium, formamidinium, I3, and Br3. However, when the stoichiometric ratio is changed, the photoelectric properties reflect those of different materials, making it difficult to study the physical properties of the quaternary perovskite. In this study, the optical properties of perovskite materials with various stoichiometric ratios were measured using ellipsometry, and the results were analyzed using an optical simulation model. Because it is difficult to analyze the spectral pattern according to composition using the existing method of statistical regression analysis, an artificial neural network (ANN) structure was constructed to enable the hyperregression analysis of n-dimensional variables. Finally, by inputting the stoichiometric ratios used in the fabrication and the wavelength range to the trained artificial intelligence model, it was confirmed that the optical properties were similar to those measured with an ellipsometer. The refractive index and extinction coefficient extracted through the ellipsometry analysis show a tendency consistent with the color change of the specimen, and have a similar shape to that reported in the literature. When the optical properties of the unmodified perovskite are predicted using the verified artificial intelligence model, a very complex change in pattern is observed, which is impossible to analyze with a general regression method. It can be seen that this change in optical properties is well maintained, even during rapid variations in the pattern according to the change in composition. In conclusion, hyperregression analysis with n-dimensional variables can be performed for the spectral patterns of thin-film materials using a simple big data construction method.

Two-stage binary classifier for neuromuscular disorders using surface electromyography feature extraction and selection.

If surface electromyography (sEMG) can be used to determine neuromuscular disorders, it can diagnose conditions more easily than needle electromyography. In this study, sEMG during maximum voluntary isometric contraction and repetitive exercise was measured, and normal, myopathy, and neuropathy were classified with high accuracy using these signals. First, a two-stage binary classifier model was constructed to classify the patient group and the normal group and categorize the cases assigned to the patient group into myopathy and neuropathy groups. To this end, features related to muscle activity and muscle fatigue were extracted using activity analysis and frequency analysis of the sEMG signal. Since the features for high performance are different for each classifier, the features with statistical differences in the data of each class were selected for each classifier. The selected features and a two-stage binary classifier were distinguished with an accuracy of 86.9%. This shows an accuracy higher than 82.3%, which was found for the two-stage binary classifier without feature selection and 73.9% of the multi-classifier. Through this, the possibility of using sEMG to diagnose neuromuscular disorders was confirmed.

Microwave-assisted ultrafast in-situ growth of N-doped carbon quantum dots on multiwalled carbon nanotubes as an efficient electrocatalyst for photovoltaics.

Multiwalled carbon nanotubes (MWCNTs) are at the forefront of metal-free electrocatalysts, however, the performance is still limited due to lack of functionality and dispersion. Coupling of MWCNTs with nitrogen doped carbon quantum dots (NCQDs) can impart the required active sites and dispersion. For the purpose, NCQDs are generally attached to MWCNTs by multistep processing, such as NCQDs synthesis, followed by their complex purification, surface activation, and crosslinking with MWCNT. The scalability of such a multistep process is limited, which is addressed by direct microwave-assisted growth of NCQDs on MWCNT. The concentration of reactants of NCQDs synthesis was optimized (with respect to MWCNTs), to achieve controlled direct growth of NCQDs on MWCNTs. The proposed strategy significantly reduced time and energy consumption, along with providing an overlapped interface for the fast charge transfer. Moreover, NCQDs' growth effectively modulated the surface reactivity and internal band structure of the MWCNTs. In response, dye-sensitized solar cells employing NCQDs modified MWCNT as a counter electrode showed 50% higher photovoltaic performance as compared to bare MWCNTs.

Solution-Processed ZnxCd1-xS Buffer Layers for Vapor Transport-Deposited SnS Thin-Film Solar Cells: Achieving High Open-Circuit Voltage.

As an alternative buffer material to CdS, ZnxCd1-xS buffer layers for vapor transport-deposited SnS thin-film solar cells (TFSCs) were fabricated using the successive ionic layer adsorption and reaction (SILAR) method. Varying the Zn-to-Cd ratio resulted in a series of ZnxCd1-xS thin films with controllable band gaps in the range of 2.40-3.65 eV. The influence of the Zn-to-Cd ratio on the cell performance was investigated in detail. The Zn0.34Cd0.66S buffer layer was found to be the optimal composition for SnS TFSCs, and a record open-circuit voltage (Voc) of 0.405 V was achieved with an efficiency of 3.72%, whereas the SILAR-CdS buffer layer rendered a Voc of 0.324 V. The improvement in Voc when using the Zn0.34Cd0.66S buffer layer was corroborated by the spike-type conduction band offset of 0.35 eV with the SnS absorber, as revealed by the X-ray photoelectron spectroscopy analysis. In addition, minimized interfacial recombination at the SnS/Zn0.34Cd0.66S heterojunction was confirmed by the temperature-dependent Voc analysis under illuminated conditions.

Na-Mediated Stoichiometry Control of FeS2 Thin Films: Suppression of Nanoscale S-Deficiency and Improvement of Photoresponse.

Control of the constituent phase and stoichiometry of iron pyrite (FeS2) is a prerequisite for high-performance photovoltaic devices based on this material. If the pyrite contains sulfur-deficiency-related secondary phases which have a metallic character and a high possibility of coexistence in pyrite films, then significant carrier recombination is expected. In this work, the beneficial role of Na in suppressing the formation of nanoscale or amorphous sulfur-deficient secondary phases is reported with experimental evidence, leading to a higher phase purity for solution-processed pyrite films. The potential reduction of charge recombination via these metallic secondary phases results in significant improvements in both the photopotential and photocurrent intensity of Na-modified pyrite films compared with reference samples.

Performance and Uniformity Improvement in Ultrathin Cu(In,Ga)Se2 Solar Cells with a WO x Nanointerlayer at the Absorber/Transparent Back-Contact Interface.

Thinning CIGSe absorber layer to less than 500 nm is desirable for reducing the cost per unit watt of photovoltaic-generated electricity, and also, the semitransparent solar cell based on such a thin absorber can be used in bifacial and superstrate configurations if the back electrode is transparent. In this study, a WO x layer is inserted between Cu(In,Ga)Se2 (CIGSe) absorber and tin-doped indium oxide back-contact to enhance the hole collection at the back electrode. A WO x interlayer with a thickness of 6 nm is found to be optimum because it causes a ∼38% relative increase in the fill factor of a ∼450 nm thick CIGSe-based device compared to the reference device without a WO x interlayer. While fixing the thickness of CIGSe, increasing the WO x interlayer thickness to ≥6 nm results in decreases of solar cell parameters primarily because of the emergence of a GaO x interfacial layer at the CIGSe/WO x junction.

The monoclonal antibody for discrimination of natural honey against artificial honey.

BACKGROUND: Honey is a natural product used as food, medicine, or cosmetics for very long time and is made by bees. Honey contains various components such as sugar, protein, minerals, and vitamins. Honey is made by Apis cerana or Apis mellifera, which commonly has major royal jelly proteins (MRJPs) as a major protein. To discriminate between natural honey (NH) and artificial honey (AH), many researchers tried method of physicochemical analysis. However, the analysis results were ambiguous and not stable. RESULTS: We have produced a monoclonal antibody that recognizes MRJPs of honeys in common. Monoclonal antibody has advantage such as accuracy, sensitivity, and stability as the standard. The specificity and affinity of produced antibody were measured by western blotting and enzyme-linked immunosorbent assay. As a result, this monoclonal antibody specifically recognized MRJPs of NH and did not recognize AH which has not including MRJPs. CONCLUSION: Natural honey could be able to distinguish from AH accurately by using this monoclonal antibody. Also, this method could be commercially applicable.

Increased miR-223 expression in foetal organs is a signature of acute chorioamnionitis with systemic consequences.

Acute chorioamnionitis, frequently observed in preterm placentas, is a major risk factor for the development of infection and non-infection-related adverse perinatal outcomes. MicroRNAs play important roles in immune cell development and function as well as in the development of cancers and neurologic diseases. We sought to investigate the changes in microRNA-223 (miR-223) expression and the functional significance of the changes in miR-223 expression in foetal organs in the presence of acute chorioamnionitis. Using formalin-fixed, paraffin-embedded (FFPE) tissue samples from foetal or neonatal autopsy cases, which are the most practical option to study the changes in several organs simultaneously, miR-223 expression profiles in foetal thymus, lung and liver were compared between cases with and without acute chorioamnionitis. Total RNA was extracted from FFPE specimens and qRT-PCR was conducted. miR-223-3p expression levels in foetal thymus (2.55-fold), lung (1.93-fold) and liver (1.70-fold) were significantly higher in cases with acute chorioamnionitis than in those without. Transfection of pre-miR-223-3p in Jurkat cells and luciferase assay and ribonucleoprotein immunoprecipitation followed by qRT-PCR analysis confirmed the binding of miR-223 to the 3' untranslated region (3'UTR) of forkhead box O1 (FoxO1) mRNA and the regulation of FoxO1 by miR-223. We report for the first time that foetuses with inflammation in the chorioamniotic membranes show increased expression of miR-223 in the thymus, lung and liver. Furthermore, FoxO1 is a target of miR-223. These findings suggest that post-transcriptional regulation of genes by miR-223 is a component of the foetal inflammatory response, which has systemic consequences in the foetus.

Identification of genes dysregulated by elevation of microRNA-210 levels in human trophoblasts cell line, Swan 71.

PROBLEM: Preeclampsia is a serious pregnancy disorder characterized by gestational hypertension and proteinuria. miR-210 is significantly overexpressed in the placentas of preeclampsia patients. METHOD OF STUDY: Swan 71 cells, first-trimester human trophoblastic cell line, were transfected with hsa-miR-210-3p oligonucleotides by electroporation. Altered transcriptome was analyzed using microarray technique. Differentially expressed genes (DEGs) were clustered into Gene Ontology annotation biological processes. The extent of physical interaction between miR-210 and IGFBP3 mRNA was assessed via ribonucleoprotein immunoprecipitation. RESULTS: Microarray analysis showed 408 DEGs by elevated levels of miR-210 in Swan 71 cells. These genes were enriched in several biological processes involved in the pathogenesis of preeclampsia. IGFBP3, a gene associated with preeclampsia pathophysiology, was validated as a target gene of miR-210. CONCLUSION: We have demonstrated that elevated miR-210 levels in human trophoblast alter the expression profile of known preeclampsia-associated genes, and of gene targets involved in various biological processes essential to preeclampsia progression.

Cinnamaldehyde derivatives inhibit degranulation and inflammatory mediator production in rat basophilic leukemia cells.

Mast cells play a critical role in allergic diseases. Therefore, development of new therapeutic agents that suppresses the activation of mast cells may help prevent or treat allergic diseases. Here, we investigated the anti-allergic effects of 4-chloro-cinnamaldehyde and 4-trifluoro-cinnamaldehyde in RBL-2H3 cells. ß-Hexosaminidase assays revealed that degranulation of RBL-2H3 cells was decreased following treatment with 60µM 4-chloro-cinnamaldehyde or 4-trifluoro-cinnamaldehyde. Moreover, quantitative real-time reverse transcription polymerase chain reaction showed that the relative expression levels of tumor necrosis factor-α, interleukin-4, and cyclooxygenase-2 mRNAs were decreased in RBL-2H3 cells treated with 4-chloro-cinnamaldehyde and 4-trifluoro-cinnamaldehyde in a concentration-dependent manner. Additionally, 4-chloro-cinnamaldehyde blocked the phosphorylation of MKKs and MAPKs. These data clearly suggested that 4-chloro-cinnamaldehyde and 4-trifluoro-cinnamaldehyde had inhibitory effects on the inflammatory responses of mast cells and may have potential as novel therapeutic agents for the prevention or treatment of allergic diseases.

Coptis chinensis Franch. extract up-regulate type I helper T-cell cytokine through MAPK activation in MOLT-4 T cell.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried rhizome of Coptis chinensis Franch. (Huanglian) has been widely used in Asian traditional medicine. It was already known that Coptis chinensis Franch. rhizome has various pharmacological properties including its anti-oxidant, anti-cancer, and anti-inflammatory activity. AIM OF THE STUDY: To evaluate the immune-enhancement effect of the Coptis chinensis Franch. rhizome extract on helper T cells and its signaling mechanism. MATERIALS AND METHODS: MOLT-4 human T cell line was used to investigate the effect of the Coptis chinensis Franch. rhizome extract. Cell viability was measured by the MTT assay and cytokine expression level was analyzed by ELISA and qRTPCR. MAPKs signal molecule's activation level was detected by immunoblotting. RESULTS: The expression of IFN-γ, a cytokine of type I helper T (Th1) cell, increased; however, IL-4 was not affected by the Coptis chinensis Franch. rhizome extract. Other Th1 cytokines, such as IL-1ß, IL-2, and IL-6, also increased. These data suggest that the Coptis chinensis Franch. rhizome extract activates MOLT-4 cell to Th1 cell, not type II helper T cell. Furthermore, the Coptis chinensis Franch. rhizome extract activates the Mitogen-activated protein kinase (MAPKs) signaling pathways. CONCLUSION: The results obtained from this study suggest that the Coptis chinensis Franch. rhizome extract should be used as an immune enhancer in anti-inflammatory medicine, adjuvant materials, and as a supplement to treat weakened immune system.

Carbon-Impurity Affected Depth Elemental Distribution in Solution-Processed Inorganic Thin Films for Solar Cell Application.

A common feature of the inorganic thin films including Cu(In,Ga)(S,Se)2 fabricated by nonvacuum solution-based approaches is the doubled-layered structure, with a top dense inorganic film and a bottom carbon-containing residual layer. Although the latter has been considered to be the main efficiency limiting factor, (as a source of high series resistance), the exact influence of this layer is still not clear, and contradictory views are present. In this study, using a CISe as a model system, we report experimental evidence indicating that the carbon residual layer itself is electrically benign to the device performance. Conversely, carbon was found to play a significant role in determining the depth elemental distribution of final film, in which carbon selectively hinders the diffusion of Cu during selenization, resulting in significantly Cu-deficient top CISe layer while improving the film morphology. This carbon-affected compositional and morphological impact on the top CISe films is a determining factor for the device efficiency, which was supported by the finding that CISe solar cells processed from the precursor film containing intermediate amount of carbon demonstrated high efficiencies of up to 9.15% whereas the performances of the devices prepared from the precursor films with very high and very low carbon were notably poor.

The Role of Positron Emission Tomography/Computed Tomography in Management and Prediction of Survival in Pancreatic Cancer.

The role of positron emission tomography (PET) and PET/computed tomography (CT) in the management of pancreatic cancer patients has not been clearly established. Although value of PET/CT in the staging of pancreatic cancer is still being debated, several studies pointed to its superior role in determining therapy response, recurrence detection, and survival prediction in comparison to conventional imaging including contrast-enhanced CT. This article reviews the current literature on usefulness of PET/CT in the management of pancreatic cancer patients.

Enhanced Photoelectrochemical Solar Water Splitting Using a Platinum-Decorated CIGS/CdS/ZnO Photocathode.

A Cu(InGa)Se2 film was modified with CdS/ZnO for application to solar water splitting. Platinum was electrodeposited on the ZnO layer as a hydrogen evolution catalyst. The effects of the electroplating time and acidity level of the electrolyte on the photocurrent density were studied. The highest photocurrent density of -32.5 mA/cm(2) under 1.5 AM illumination was achieved with an electroplating time of 30 min at a pH of 9. This photocurrent density is higher than those reported in previous studies. The markedly high performance of the CIGS/CdS/ZnO photocathode was rationalized in terms of its type II cascade structure that facilitated efficient charge separation at the interface junction.

Carbon monoxide poisoning-induced cardiomyopathy from charcoal at a barbecue restaurant: a case report.

OBJECTIVE: Acute carbon monoxide poisoning has important clinical value because it can cause severe adverse cardiovascular effects and sudden death. Acute carbon monoxide poisoning due to charcoal is well reported worldwide, and increased use of charcoal in the restaurant industry raises concern for an increase in occupational health problems. We present a case of carbon monoxide poisoning induced cardiomyopathy in a 47-year-old restaurant worker. MATERIALS AND METHODS: A male patient was brought to the emergency department to syncope and complained of left chest pain. Cardiac angiography and electrocardiography were performed to rule out acute ischemic heart disease, and cardiac markers were checked. After relief of the symptoms and stabilization of the cardiac markers, the patient was discharged without any complications. RESULTS: Electrocardiography was normal, but cardiac angiography showed up to a 40% midsegmental stenosis of the right coronary artery with thrombotic plaque. The level of cardiac markers was elevated at least 5 to 10 times higher than the normal value, and the carboxyhemoglobin concentration was 35% measured at one hour after syncope. Following the diagnosis of acute carbon monoxide poisoning induced cardiomyopathy, the patient's medical history and work exposure history were examined. He was found to have been exposed to burning charcoal constantly during his work hours. CONCLUSIONS: Severe exposure to carbon monoxide was evident in the patient because of high carboxyhemoglobin concentration and highly elevated cardiac enzymes. We concluded that this exposure led to subsequent cardiac injury. He was diagnosed with acute carbon monoxide poisoning-induced cardiomyopathy due to an unsafe working environment. According to the results, the risk of exposure to noxious chemicals such as carbon monoxide by workers in the food service industry is potentially high, and workers in this sector should be educated and monitored by the occupational health service to prevent adverse effects.

Carbon- and oxygen-free Cu(InGa)(SSe)2 solar cell with a 4.63% conversion efficiency by electrostatic spray deposition.

We have demonstrated the first example of carbon- and oxygen-free Cu(In,Ga)(SSe)2 (CIGSSe) absorber layers prepared by electrospraying a CuInGa (CIG) precursor followed by annealing, sulfurization, and selenization at elevated temperature. X-ray diffraction and scanning electron microscopy showed that the amorphous as-deposited (CIG) precursor film was converted into polycrystalline CIGSSe with a flat-grained morphology after post-treatment. The optimal post-treatment temperature was 300 °C for annealing and 500 °C for both sulfurization and selenization, with a ramp rate of 5 °C/min. The carbon impurities in the precursor film were removed by air annealing, and oxide that was formed during annealing was removed by sulfurization. The fabricated CIGSSe solar cell showed a conversion efficiency of 4.63% for a 0.44 cm(2) area, with Voc = 0.4 V, Jsc = 21 mA/cm(2), and FF = 0.53.

Amorphous Cu-In-S nanoparticles as precursors for CuInSe2 thin-film solar cells with a high efficiency.

CuInSe2 (CISe) absorber layers for thin-film solar cells were fabricated through the selenization of amorphous Cu-In-S nanoparticles, which were prepared by using a low-temperature colloidal process within one minute without any external heating. Two strategies for obtaining highly dense CISe absorber films were used in this work; the first was the modification of nanoparticle surface through chelate complexation with ethanolamine, and the second strategy utilized the lattice expansion that occurred when S atoms in the precursor particles were replaced with Se during selenization. The synergy of these two strategies allowed formation of highly dense CISe thin films, and devices fabricated using the absorber layer demonstrated efficiencies of up to 7.94% under AM 1.5G illumination without an anti-reflection coating.