Artificial Synapse Based on a δ-FAPbI3/Atomic-Layer-Deposited SnO2 Bilayer Memristor.

Halide perovskite-based resistive switching memory (memristor) has potential in an artificial synapse. However, an abrupt switch behavior observed for a formamidinium lead triiodide (FAPbI3)-based memristor is undesirable for an artificial synapse. Here, we report on the δ-FAPbI3/atomic-layer-deposited (ALD)-SnO2 bilayer memristor for gradual analogue resistive switching. In comparison to a single-layer δ-FAPbI3 memristor, the heterojunction δ-FAPbI3/ALD-SnO2 bilayer effectively reduces the current level in the high-resistance state. The analog resistive switching characteristics of δ-FAPbI3/ALD-SnO2 demonstrate exceptional linearity and potentiation/depression performance, resembling an artificial synapse for neuromorphic computing. The nonlinearity of long-term potentiation and long-term depression is notably decreased from 12.26 to 0.60 and from -8.79 to -3.47, respectively. Moreover, the δ-FAPbI3/ALD-SnO2 bilayer achieves a recognition rate of ≤94.04% based on the modified National Institute of Standards and Technology database (MNIST), establishing its potential in an efficient artificial synapse.

Cooperative Design of the Ag3PO4/NH2-MIL-88B (Fe/Co) Heterojunction Integrated with Conductive Polypyrrole for Advanced Photocatalytic Water Purification.

Wastewater treatments using photocatalysts and metal-organic frameworks (MOFs) have gained increasing importance due to their catalytic reactions leading to the decomposition of dyes and organic pollutants without generating secondary pollutants. This work aims at developing an advanced photocatalytic fabric by conceiving a heterojunction of NH2-MIL-88B (Fe/Co) (n-type) and Ag3PO4 (p-type) and increasing the electrical conductivity to facilitate charge transfer at the heterojunction. Of particular interest is the design of a conductive Z-scheme heterophotocatalytic fabric by implementing polypyrrole (PPy) between the heterocatalysts and to investigate the role of the heterojunction and increased conductivity in the generation of reactive species and the photocatalytic mechanism. The electrochemical characterization evinces that the enhanced photocatalytic reaction by the conductive heterojunction is attributed to the efficient electron-hole separation and the increased redox power by the Z-scheme construction. Notably, the implementation of PPy not only accelerated the photocatalytic reactivity by the promoted charge mobility but also improved the structural stability of the catalysts by gluing them on the fabric substrate. The developed photocatalytic system demonstrated significantly enhanced purification performance compared with a single photocatalytic system and showed consistent performance with repeated use cycles. The result of this study implicates that electrical conductivity in a photocatalytic system plays a crucial role in the photocatalytic mechanism, charge mobility, and photocatalytic reactivity.

A floating photocatalytic fabric integrated with a AgI/UiO-66-NH2 heterojunction as a facile strategy for wastewater treatment.

With an increased need of wastewater treatment, application of photocatalysts has drawn growing research attention as an advanced water remediation strategy. Herein, a floating photocatalytic fabric in a woven construction was developed for removal of Rhodamine B (RhB) in water. For an efficient photocatalytic reaction, AgI nanoparticles were grown on the surface of UiO-66-NH2 crystals in a layered structure, forming a heterojunction system on a cotton yarn, and this was woven with polypropylene yarn. The floating photocatalyst demonstrated the maximized light utilization and adequate contact with contaminated water. Through the heterojunction system, the electrons and holes were effectively separated to generate reactive chemical species, and this eventually led to an enhanced photocatalytic performance of AgI/UiO@fabric reaching 98% removal efficiency after 2 hours of irradiation. Photodegradation of RhB occurred mainly by superoxide radicals and holes, which were responsible for de-ethylation and decomposition of an aromatic ring, respectively. The kinetics of the photocatalytic reaction suggested that circulation of solution by stirring affected the photocatalytic removal rate. The recycle test demonstrated the potential long-term applicability of the developed material with structural integrity and catalytic stability. This study highlights the proof-of-concept of a floating photocatalytic material for facile and effective water remediation with repeated usability.

Atmospheric Humidity Underlies Irreproducibility of Formamidinium Lead Iodide Perovskites.

Metal halide perovskite solar cells (PSCs) are infamous for their batch-to-batch and lab-to-lab irreproducibility in terms of stability and performance. Reproducible fabrication of PSCs is a critical requirement for market viability and practical commercialization. PSC irreproducibility plagues all levels of the community; from institutional research laboratories, start-up companies, to large established corporations. In this work, the critical function of atmospheric humidity to regulate the crystallization and stabilization of formamidinium lead triiodide (FAPbI3) perovskites is unraveled. It is demonstrated that the humidity content during processing induces profound variations in perovskite stoichiometry, thermodynamic stability, and optoelectronic quality. Almost counterintuitively, it is shown that the presence of humidity is perhaps indispensable to reproduce phase-stable and efficient FAPbI3-based PSCs.

Effects of MgF2anti-reflection coating on optical losses in metal halide perovskite solar cells.

The importance of light management for perovskite solar cells (PSCs) has recently been emphasized because their power conversion efficiency approaches their theoretical thermodynamic limits. Among optical strategies, anti-reflection (AR) coating is the most widely used method to reduce reflectance loss and thus increase light-harvesting efficiency. Monolayer MgF2is a well-known AR material because of its optimal refractive index, simple fabrication process, and physical and chemical durabilities. Nevertheless, quantitative estimates of the improvement achieved by the MgF2AR layer are lacking. In this study, we conducted theoretical and experimental evaluations to assess the AR effect of MgF2on the performance of formamidinium lead-triiodide PSCs. A sinusoidal tendency to enhance the short-circuit current density (JSC) was observed depending on the thickness, which was attributed to the interference of the incident light. A transfer matrix method-based simulation was conducted to calculate the optical losses, demonstrating the critical impact of reflectance loss on theJSCimprovement. The predictedJSCs values, depending on the perovskite thickness and the incident angle, are also presented. The combined use of experimental and theoretical approaches offers notable advantages, including accurate interpretation of photocurrent generation, detailed optical analysis of the experimental results, and device performance predictions under unexplored conditions.

Effect of Operating Conditions on the Gasification of Pet-Coke Water Slurry in an Entrained-Flow Gasifier Simulation.

Petroleum coke, commonly known as pet-coke, represents a promising and cost-effective alternative fuel source, produced as a byproduct of large-scale heavy crude oil refining. This study first simulated the gasification process of pet-coke slurry using a three-dimensional computational fluid dynamics (CFD) approach based on the Eulerian-Lagrangian method. The simulation was carried out in a 2-ton-per-day (2TPD) entrained-flow gasifier, aiming to optimize the production of hydrogen (H2) and carbon monoxide (CO) as synthetic gases. This study investigated the effects of operational parameters, including the oxygen/slurry ratio and moisture content in the slurry, on various aspects such as fluid dynamics, temperature distribution, particle trajectories, carbon conversion, and gas composition within the pet-coke slurry gasifier. The base conditions of the simulation were meticulously cross-validated with high-precision experimental data. The results indicated that higher oxygen/slurry ratios led to increased concentrations of carbon dioxide (CO2) and decreased fractions of H2, primarily due to the prevalence of the reverse water-gas shift reaction. Moreover, raising the moisture content in the pet-coke slurry led to decreased CO levels and enhanced production of H2 and CO2, triggered by the activation of the forward water-gas shift reaction. These results underscore the potential of pet-coke slurry as a favorable feedstock for syngas production and the achievement of carbon neutrality through the careful optimization of operational conditions. Our findings provide valuable insights for further experimental exploration and the development of practical applications for pet-coke gasification.

Enhancing Efficiency and Stability of Tin Halide Perovskite Light-Emitting Diodes via Engineered Alkali/Multivalent Metal Salts.

Sn-based perovskite light-emitting diodes (PeLEDs) have emerged as promising alternatives to Pb-based PeLEDs with their rapid increase in performance owing to the various research studies on inhibiting Sn oxidation. However, the absence of defect passivation strategies for Sn-based perovskite LEDs necessitates further research in this field. We performed systematic studies to investigate the design rules for defect passivation agents for Sn-based perovskites by incorporating alkali/multivalent metal salts with various cations and anions. From the computational and experimental analyses, sodium trifluoromethanesulfonate (NaTFMS) was found to be the most effective passivation agent for PEA2SnI4 films among the explored candidate agents owing to favorable reaction energetics to passivate iodide Frenkel defects. Consequently, the incorporation of NaTFMS facilitates the formation of uniform films with relatively large crystals and reduced Sn4+. The NaTFMS-containing PEA2SnI4 PeLEDs demonstrate an improved luminance of 138.9 cd/m2 and external quantum efficiency (EQE) of 0.39% with an improved half-lifetime of more than threefold. This work provides important insight into the design of defect passivation agents for Sn-based perovskites.

Spatial Variation in COVID-19 Mortality in New York City and Its Association with Neighborhood Race, Ethnicity, and Nativity Status.

We examined the association between variation in COVID-19 deaths and spatial differences in the racial, ethnic, and nativity-status composition of New York City neighborhoods, which has received little scholarly attention. Using COVID-19 mortality data (through 31 May 2021) and socioeconomic and demographic data from the American Community Survey at the Zip Code Tabulation Area level as well as United-Hospital-Fund-level neighborhood data from the Community Health Survey of the New York City Department of Health and Mental Hygiene, we employed multivariable Poisson generalized estimating equation models and assessed the association between COVID-19 mortality, racial/ethnic/nativity-status composition, and other ecological factors. Our results showed an association between neighborhood-level racial and ethnic composition and COVID-19 mortality rates that is contingent upon the neighborhood-level nativity-status composition. After multivariable adjustment, ZCTAs with large shares of native-born Blacks and foreign-born Hispanics and Asians were more likely to have higher COVID-19 mortality rates than areas with large shares of native-born Whites. Areas with more older adults and essential workers, higher levels of household crowding, and population with diabetes were also at high risk. Small-area analyses of COVID-19 mortality can inform health policy responses to neighborhood inequalities on the basis of race, ethnicity, and immigration status.

Copper Oxide Spike Grids for Enhanced Solution Transfer in Cryogenic Electron Microscopy.

The formation of uniform vitreous ice is a crucial step in the preparation of samples for cryogenic electron microscopy (cryo-EM). Despite the rapid technological progress in EM, controlling the thickness of vitreous ice on sample grids with reproducibility remains a major obstacle to obtaining high-quality data in cryo-EM imaging. The commonly employed classical blotting process faces the problem of excess water that cannot be absorbed by the filter paper, resulting in the formation of thick and heterogeneous ice. In this study, we propose a novel approach that combines the recently developed nanowire self-wicking technique with the classical blotting method to effectively control the thickness and homogeneity of vitrified ice. With simple procedures, we generated a copper oxide spike (COS) grid by inducing COSs on commercially available copper grids, which can effectively remove excess water during the blotting procedure without damaging the holey carbon membrane. The ice thickness could be controlled with good reproducibility compared to non-oxidized grids. Incorporated into other EM techniques, our new modification method is an effective option for obtaining high-quality data during cryo-EM imaging.

The ENCODE Uniform Analysis Pipelines.

The Encyclopedia of DNA elements (ENCODE) project is a collaborative effort to create a comprehensive catalog of functional elements in the human genome. The current database comprises more than 19000 functional genomics experiments across more than 1000 cell lines and tissues using a wide array of experimental techniques to study the chromatin structure, regulatory and transcriptional landscape of the Homo sapiens and Mus musculus genomes. All experimental data, metadata, and associated computational analyses created by the ENCODE consortium are submitted to the Data Coordination Center (DCC) for validation, tracking, storage, and distribution to community resources and the scientific community. The ENCODE project has engineered and distributed uniform processing pipelines in order to promote data provenance and reproducibility as well as allow interoperability between genomic resources and other consortia. All data files, reference genome versions, software versions, and parameters used by the pipelines are captured and available via the ENCODE Portal. The pipeline code, developed using Docker and Workflow Description Language (WDL; https://openwdl.org/) is publicly available in GitHub, with images available on Dockerhub (https://hub.docker.com), enabling access to a diverse range of biomedical researchers. ENCODE pipelines maintained and used by the DCC can be installed to run on personal computers, local HPC clusters, or in cloud computing environments via Cromwell. Access to the pipelines and data via the cloud allows small labs the ability to use the data or software without access to institutional compute clusters. Standardization of the computational methodologies for analysis and quality control leads to comparable results from different ENCODE collections - a prerequisite for successful integrative analyses.

The Monitoring and Management of an Operating Environment to Enhance the Safety of a Container-Type Energy Storage System.

The implementation of an energy storage system (ESS) as a container-type package is common due to its ease of installation, management, and safety. The control of the operating environment of an ESS mainly considers the temperature rise due to the heat generated through the battery operation. However, the relative humidity of the container often increases by over 75% in many cases because of the operation of the air conditioner which pursues temperature-first control. Humidity is a major factor which can cause safety issues such as fires owing to insulation breakdown caused by condensation. However, the importance of humidity control in ESS is underestimated compared to temperature control. In this study, temperature and humidity monitoring and management issues were addressed for a container-type ESS by building sensor-based monitoring and control systems. Furthermore, a rule-based air conditioner control algorithm was proposed for temperature and humidity management. A case study was conducted to compare the conventional and proposed control algorithms and verify the feasibility of the proposed algorithm. The results showed that the proposed algorithm reduced the average humidity by 11.4% compared to the value achieved with the existing temperature control method while also maintaining the temperature.

Staphylococcus equorum plasmid pKS1030-3 encodes auxiliary biofilm formation and trans-acting gene mobilization systems.

The foodborne bacterium Staphylococcus equorum strain KS1030 harbours plasmid pSELNU1, which encodes a lincomycin resistance gene. pSELNU1 undergoes horizontal transfer between bacterial strains, thus spreading antibiotic resistance. However, the genes required for horizontal plasmid transfer are not encoded in pSELNU1. Interestingly, a relaxase gene, a type of gene related to horizontal plasmid transfer, is encoded in another plasmid of S. equorum KS1030, pKS1030-3. The complete genome of pKS1030-3 is 13,583 bp long and encodes genes for plasmid replication, biofilm formation (the ica operon), and horizontal gene transfer. The replication system of pKS1030-3 possesses the replication protein-encoding gene repB, a double-stranded origin of replication, and two single-stranded origins of replication. The ica operon, relaxase gene, and a mobilization protein-encoding gene were detected in pKS1030-3 strain-specifically. When expressed in S. aureus RN4220, the ica operon and relaxase operon of pKS1030-3 conferred biofilm formation ability and horizontal gene transfer ability, respectively. The results of our analyses show that the horizontal transfer of pSELNU1 of S. equorum strain KS1030 depends on the relaxase encoded by pKS1030-3, which is therefore trans-acting. Genes encoded in pKS1030-3 contribute to important strain-specific properties of S. equorum KS1030. These results could contribute to preventing the horizontal transfer of antibiotic resistance genes in food.

Rational Design of a Chemical Bath Deposition Based Tin Oxide Electron-Transport Layer for Perovskite Photovoltaics.

Chemical bath deposition (CBD) is widely used to deposit tin oxide (SnOx ) as an electron-transport layer in perovskite solar cells (PSCs). The conventional recipe uses thioglycolic acid (TGA) to facilitate attachments of SnOx particles onto the substrate. However, nonvolatile TGA is reported to harm the operational stability of PSCs. In this work, a volatile oxalic acid (OA) is introduced as an alternative to TGA. OA, a dicarboxylic acid, functions as a chemical linker for the nucleation and attachment of particles to the substrate in the chemical bath. Moreover, OA can be readily removed through thermal annealing followed by a mild H2 O2 treatment, as shown by FTIR measurements. Synergistically, the mild H2 O2 treatment selectively oxidizes the surface of the SnOx layer, minimizing nonradiative interface carrier recombination. EELS (electron-energy-loss spectroscopy) confirms that the SnOx surface is dominated by Sn4+ , while the bulk is a mixture of Sn2+ and Sn4+ . This rational design of a CBD SnOx layer leads to devices with T85 ≈1500 h, a significant improvement over the TGA-based device with T80 ≈250 h. The champion device reached a power conversion efficiency of 24.6%. This work offers a rationale for optimizing the complex parameter space of CBD SnOx to achieve efficient and stable PSCs.

Patterning of Metal Halide Perovskite Thin Films and Functional Layers for Optoelectronic Applications.

In recent years, metal halide perovskites have received significant attention as materials for next-generation optoelectronic devices owing to their excellent optoelectronic properties. The unprecedented rapid evolution in the device performance has been achieved by gaining an advanced understanding of the composition, crystal growth, and defect engineering of perovskites. As device performances approach their theoretical limits, effective optical management becomes essential for achieving higher efficiency. In this review, we discuss the status and perspectives of nano to micron-scale patterning methods for the optical management of perovskite optoelectronic devices. We initially discuss the importance of effective light harvesting and light outcoupling via optical management. Subsequently, the recent progress in various patterning/texturing techniques applied to perovskite optoelectronic devices is summarized by categorizing them into top-down and bottom-up methods. Finally, we discuss the perspectives of advanced patterning/texturing technologies for the development and commercialization of perovskite optoelectronic devices.

Lead immobilization for environmentally sustainable perovskite solar cells.

Lead halide perovskites are promising semiconducting materials for solar energy harvesting. However, the presence of heavy-metal lead ions is problematic when considering potential harmful leakage into the environment from broken cells and also from a public acceptance point of view. Moreover, strict legislation on the use of lead around the world has driven innovation in the development of strategies for recycling end-of-life products by means of environmentally friendly and cost-effective routes. Lead immobilization is a strategy to transform water-soluble lead ions into insoluble, nonbioavailable and nontransportable forms over large pH and temperature ranges and to suppress lead leakage if the devices are damaged. An ideal methodology should ensure sufficient lead-chelating capability without substantially influencing the device performance, production cost and recycling. Here we analyse chemical approaches to immobilize Pb2+ from perovskite solar cells, such as grain isolation, lead complexation, structure integration and adsorption of leaked lead, based on their feasibility to suppress lead leakage to a minimal level. We highlight the need for a standard lead-leakage test and related mathematical model to be established for the reliable evaluation of the potential environmental risk of perovskite optoelectronics.

Lamin Filament Assembly Derived from the Atomic Structure of the Antiparallel Four-Helix Bundle.

The nucleoskeletal protein lamin is primarily responsible for the mechanical stability of the nucleus. The lamin assembly process requires the A11, A22, and ACN binding modes of the coiled-coil dimers. Although X-ray crystallography and chemical cross-linking analysis of lamin A/C have provided snapshots of A11 and ACN binding modes, the assembly mechanism of the entire filament remains to be explained. Here, we report a crystal structure of a coil 2 fragment, revealing the A22 interaction at the atomic resolution. The structure showed detailed structural features, indicating that two coiled-coil dimers of the coil 2 subdomain are separated and then re-organized into the antiparallel-four-helix bundle. Furthermore, our findings suggest that the ACN binding mode between coil 1a and the C-terminal part of coil 2 when the A11 tetramers are arranged by the A22 interactions. We propose a full assembly model of lamin A/C with the curvature around the linkers, reconciling the discrepancy between the in situ and in vitro observations. Our model accounts for the balanced elasticity and stiffness of the nuclear envelopes, which is essential in protecting the cellular nucleus from external pressure.

Effects of diet and castration on fatty acid composition and volatile compounds in the meat of Korean native black goats.

OBJECTIVE: This study determined the effects of dietary treatments and castration on meat quality, fatty acids (FAs) profiles, and volatile compounds in Korean native black goats (KNBG, Capra hircus coreanae), including the relationship between the population of rumen microbiomes and meat FA profiles. METHODS: Twenty-four KNBG (48.6±1.4 kg) were randomly allocated to one of four treatments arranged into a 2×2 factorial structure. The factors were dietary forage to concentrate ratio (high forage [HF, 80:20] and low forage [LF, 20:80]), and a castration treatment (castration [CA] vs non-castration [NCA]). RESULTS: Among meat quality traits, the CA group exhibited a higher percentage of crude fat and water holding capacity (p<0.05). The profiles of the saturated fatty acid (SFA) in meat sample derived from CA KNBG showed a significantly lower percentage compared to NCA individuals, due to the lower proportion of C14:0 and C18:0. Feeding a high-forage diet to KNBG increased the formation of C18:1n7, C18:3n3, C20:1n9, C22:4n6 in meat, and polyunsaturated fatty acid (PUFA) profiles (p<0.05). Consequently, the n6:n3 ratio declined (p<0.05). There was an interaction between dietary treatment and castration for formation of C20:5n3 (p<0.05), while C18:1n9, C22:6n3, monounsaturated fatty acid (MUFA) and the MUFA:SFA ratio were influenced by both diet and castration (p<0.05). Nine volatile compounds were identified and were strongly influenced by both dietary treatments, castration (p<0.05), and their interaction. In addition, principal component analysis (PCA) revealed distinctly different odor patterns in the NCA goats fed LF diets. Spearman correlation analysis showed a high correlation between rumen bacteria and meat PUFAs. CONCLUSION: These results suggest the essential effects of the rumen microbial population for the synthesis of meat FAs and volatile compounds in KNBG meat, where dietary intake and castration also contribute substantially.

Tranilast protects pancreatic ß-cells from palmitic acid-induced lipotoxicity via FoxO-1 inhibition.

Tranilast, an anti-allergic drug used in the treatment of bronchial asthma, was identified as an inhibitor of the transcription factor Forkhead box O-1 (FoxO-1) by high throughput chemical library screening in the present study. Based on FoxO-1's role in apoptotic cell death and differentiation, we examined the effect of tranilast on palmitic acid (PA)-induced cell damage in INS-1 cells. Tranilast substantially inhibited lipoapoptosis and restored glucose-stimulated insulin secretion under high PA exposure. Moreover, PA-mediated downregulation of PDX-1, MafA, and insulin expression was attenuated by tranilast. PA-induced oxidative and ER stress were also reduced in the presence of tranilast. These protective effects were accompanied by increased phosphorylation and decreased nuclear translocation of FoxO-1. Conversely, the effects of tranilast were diminished when treated in transfected cells with FoxO-1 phosphorylation mutant (S256A), suggesting that the tranilast-mediated effects are associated with inactivation of FoxO-1. Examination of the in vivo effects of tranilast using wild type and diabetic db/db mice showed improved glucose tolerance along with FoxO-1 inactivation in the pancreas of the tranilast-treated groups. Thus, we report here that tranilast has protective effects against PA-induced lipotoxic stress in INS-1 cells, at least partly, via FoxO-1 inactivation, which results in improved glucose tolerance in vivo.

Crystal Structure of the Metallo-Endoribonuclease YbeY from Staphylococcus aureus.

Endoribonuclease YbeY is specific to the single-stranded RNA of ribosomal RNAs and small RNAs. This enzyme is essential for the maturation and quality control of ribosomal RNA in a wide range of bacteria and for virulence in some pathogenic bacteria. In this study, we determined the crystal structure of YbeY from Staphylococcus aureus at a resolution of 1.9 Å in the presence of zinc chloride. The structure showed a zinc ion at the active site and two molecules of tricarboxylic acid citrate, which were also derived from the crystallization conditions. Our structure showed the zinc ion-bound local environment at the molecular level for the first time. Molecular comparisons were performed between the carboxylic moieties of citrate and the phosphate moiety of the RNA backbone, and a model of YbeY in complex with a single strand of RNA was subsequently constructed. Our findings provide molecular insights into how the YbeY enzyme recognizes single-stranded RNA in bacteria.

Suppressing ion migration in metal halide perovskite via interstitial doping with a trace amount of multivalent cations.

Cations with suitable sizes to occupy an interstitial site of perovskite crystals have been widely used to inhibit ion migration and promote the performance and stability of perovskite optoelectronics. However, such interstitial doping inevitably leads to lattice microstrain that impairs the long-range ordering and stability of the crystals, causing a sacrificial trade-off. Here, we unravel the evident influence of the valence states of the interstitial cations on their efficacy to suppress the ion migration. Incorporation of a trivalent neodymium cation (Nd3+) effectively mitigates the ion migration in the perovskite lattice with a reduced dosage (0.08%) compared to a widely used monovalent cation dopant (Na+, 0.45%). The photovoltaic performances and operational stability of the prototypical perovskite solar cells are enhanced with a trace amount of Nd3+ doping while minimizing the sacrificial trade-off.