Isolation and Reactivity of Arylnickel(II) Complexes in Nickel-Catalyzed Borylation of Aryl Fluorosulfates

Aryl fluorosulfates have emerged as versatile SuFExable substrates, harnessing the reactivity of the S-F bond. In this study, we unveil their alternative synthetic utility in nickel-catalyzed borylation via C-O bond activation. This method highlights mild reaction conditions, a broad substrate scope, and moderate functional group tolerance, rendering it a practical and appealing approach for synthesizing a diverse array of aryl boronate esters. Furthermore, computational analysis sheds light on the reaction pathways, uncovering the participation of LNi(0) and LNi(II)ArX species. This insight is supported by the 31P NMR reaction monitoring along with isolation and single-crystal X-ray structural elucidation of well-defined arylnickel(II) intermediates obtained from the oxidative addition of aryl fluorosulfates. A comprehensive investigation, merging experimental and computational approaches, deepens our understanding of the alternative reactivity of SuFExable substrates.

Highly Macroporous Polyimide with Chemical Versatility Prepared from Poly(amic acid) Salt-Stabilized High Internal Phase Emulsion Template

Macroporous polymers have gained significant attention due to their unique mass transport and size-selective properties. In this study, we focused on Polyimide (PI), a high-performance polymer, as an ideal candidate for macroporous structures. Despite various attempts to create macroporous PI (Macro PI) using emulsion templates, challenges remained, including limited chemical diversity and poor control over pore size and porosity. To address these issues, we systematically investigated the role of poly(amic acid) salt (PAAS) polymers as macrosurfactants and matrices. By designing 12 different PAAS polymers with diverse chemical structures, we achieved stable high internal phase emulsions (HIPEs) with >80 vol % internal volume. The resulting Macro PIs exhibited exceptional porosity (>99 vol %) after thermal imidization. We explored the structure-property relationships of these Macro PIs, emphasizing the importance of controlling pore size distribution. Furthermore, our study demonstrated the utility of these Macro PIs as separators in Li-metal batteries, providing stable charging-discharging cycles. Our findings not only enhance the understanding of emulsion-based macroporous polymers but also pave the way for their applications in advanced energy storage systems and beyond.

Analogous Design of a Microlayered Silicon Oxide-Based Electrode to the General Electrode Structure for Thin-Film Lithium-Ion Batteries

Development of miniaturized thin-film lithium-ion batteries (TF-LIBs) using vacuum deposition techniques is crucial for low-scale applications, but addressing low energy density remains a challenge. In this work, structures analogous to SiOx-based thin-film electrodes are designed with close resemblance to traditional LIB slurry formulations including active material, conductive agent, and binder. The thin-film is produced using mid-frequency sputtering with a single hybrid target consisting of SiOx nanoparticles, carbon nanotubes, and polytetrafluoroethylene. The thin-film SiOx/PPFC (plasma-polymerized fluorocarbon) involves a combination of SiOx and conductive carbon within the PPFC matrix. This results in enhanced electronic conductivity and superior elasticity and hardness in comparison to a conventional pure SiOx-based thin-film. The electrochemical performance of the half-cell consisting of thin-film SiOx/PPFC demonstrates remarkable cycling stability, with a capacity retention of 74.8% up to the 1000th cycle at 0.5 C. In addition, a full cell using the LiNi0.6Co0.2Mn0.2O2 thin-film as the cathode material exhibits an exceptional initial capacity of ≈120 mAh g-1 at 0.1 C and cycle performance, marked by a capacity retention of 90.8% from the first cycle to the 500th cycle at a 1 C rate. This work will be a stepping stone for the AM/CB/B composite electrodes in TF-LIBs.

Practical Applications of Self-Healing Polymers Beyond Mechanical and Electrical Recovery

Self-healing polymeric materials, which can repair physical damage, offer promising prospects for protective applications across various industries. Although prolonged durability and resource conservation are key advantages, focusing solely on mechanical recovery may limit the market potential of these materials. The unique physical properties of self-healing polymers, such as interfacial reduction, seamless connection lines, temperature/pressure responses, and phase transitions, enable a multitude of innovative applications. In this perspective, the diverse applications of self-healing polymers beyond their traditional mechanical strength are emphasized and their potential in various sectors such as food packaging, damage-reporting, radiation shielding, acoustic conservation, biomedical monitoring, and tissue regeneration is explored. With regards to the commercialization challenges, including scalability, robustness, and performance degradation under extreme conditions, strategies to overcome these limitations and promote successful industrialization are discussed. Furthermore, the potential impacts of self-healing materials on future research directions, encompassing environmental sustainability, advanced computational techniques, integration with emerging technologies, and tailoring materials for specific applications are examined. This perspective aims to inspire interdisciplinary approaches and foster the adoption of self-healing materials in various real-life settings, ultimately contributing to the development of next-generation materials.

A microcapsule-based reusable self-reporting system using a donor-acceptor Stenhouse adduct

Self-reporting systems automatically indicate damaged or corroded surfaces via color changes or fluorescence. In this study, a novel reusable self-reporting system is developed by exploiting the reversibility of a donor-acceptor Stenhouse adduct (DASA). The synthesized DASA precursor exhibits a color change when damaged upon reaction with diethylamine, and returns to its colorless form upon irradiation with visible light. Microcapsules are synthesized with a core comprising styrene and the DASA precursor, along with a shell formed of urea and formaldehyde. The optimal particle size and shell thickness of the microcapsules are 225 μm and 0.17 μm, respectively. The DASA precursor-containing microcapsules are embedded in a PEG gel matrix with secondary amine groups. This coating system, initially colorless, exhibits a color change, becoming pink after being damaged by scratching due to the reaction between the DASA precursor released from ruptured microcapsules with the secondary amine groups of the PEG gel, thus demonstrating self-reporting characteristics. Furthermore, the colored surface is restored to its initial colorless state by irradiation with visible light for 1.5 hours, demonstrating the reusability of the self-reporting system.

AFM Imaging Reveals MicroRNA-132 to be a Positive Regulator of Synaptic Functions

The modification of synaptic and neural connections in adults, including the formation and removal of synapses, depends on activity-dependent synaptic and structural plasticity. MicroRNAs (miRNAs) play crucial roles in regulating these changes by targeting specific genes and regulating their expression. The fact that somatic and dendritic activity in neurons often occurs asynchronously highlights the need for spatial and dynamic regulation of protein synthesis in specific milieu and cellular loci. MicroRNAs, which can show distinct patterns of enrichment, help to establish the localized distribution of plasticity-related proteins. The recent study using atomic force microscopy (AFM)-based nanoscale imaging reveals that the abundance of miRNA(miR)-134 is inversely correlated with the functional activity of dendritic spine structures. However, the miRNAs that are selectively upregulated in potentiated synapses, and which can thereby support prospective changes in synaptic efficacy, remain largely unknown. Using AFM force imaging, significant increases in miR-132 in the dendritic regions abutting functionally-active spines is discovered. This study provides evidence for miR-132 as a novel positive miRNA regulator residing in dendritic shafts, and also suggests that activity-dependent miRNAs localized in distinct sub-compartments of neurons play bi-directional roles in controlling synaptic transmission and synaptic plasticity.

Advanced Additive Manufacturing of Structurally-Colored Architectures

Direct ink writing (DIW) stands out as a facile additive manufacturing method, minimizing material waste. Nonetheless, developing homogeneous Bingham inks with high yield stress and swift liquid-to-solid transitions for versatile 3D printing remains a challenge. In this study, high-performance Bingham inks are formulated by destabilizing silica particle suspensions in acrylate-based resin. A colloidal network forms in the shear-free state through interparticle attraction, achieved by disrupting the solvation layer of large resin molecules using polar molecules. The network is highly dense, with evenly distributed linkage strength as monodisperse particles undergo gelation at an ultra-high fraction. Crucially, the strength is calibrated to ensure a sufficiently large yield stress, while still allowing the network to reversibly melt under shear flow. The inks immediately undergo a liquid-to-solid transition upon discharge, while maintaining fluidity without nozzle clogging. The dense colloidal networks develop structural colors due to the short-range order. This enables the rapid and sophisticated drawing of structurally-colored 3D structures, relying solely on rheological properties. Moreover, the printed composite structures exhibit high mechanical stability due to the presence of the colloidal network, which expands the range of potential applications.

Regioselective Arylation of Amidoaryne Precursors via Ag-Mediated Intramolecular Oxy-Argentation

An unprecedented silver-mediated intramolecular oxy-argentation of 3-amidoaryne precursors that quickly generates a heteroarylsilver species is developed. AgF acts as both a stoichiometric fluoride source and a reagent for the formation of a benzoxazolylsilver intermediate via aryne generation. Pd-catalyzed coupling reactions of (hetero)aryl iodides with a silver species, generated in situ, allow for the synthesis of various C7-arylated benzoxazoles. As a result, an aryl group is selectively introduced into the meta-position of 3-amidobenzyne precursors. Mechanistic studies have indicated the presence of a benzoxazolylsilver intermediate and revealed that the reaction proceeds via an intramolecular oxy-argentation process, which is initiated by a direct fluoride attack on the silyl group.

Highly potent and selective phosphatidylinositol 4-kinase IIIβ inhibitors as broad-spectrum anti-rhinoviral agents

Human rhinoviruses (hRVs) cause upper and lower respiratory tract infections and exacerbate asthma and chronic obstructive pulmonary disease. hRVs comprise more than 160 strains with considerable genetic variation. Their high diversity and strain-specific interactions with antisera hinder the development of anti-hRV therapeutic agents. Phosphatidylinositol-4-kinase IIIβ (PI4KIIIβ) is a key enzyme in the phosphoinositide signalling pathway that is crucial for the replication and survival of various viruses. We identified novel PI4KIIIβ inhibitors, N-(4-methyl-5-arylthiazol)-2-amide derivatives, by generating a hit compound, 1a, from the high-throughput screening of a chemical library, followed by the optimization study of 1a. Inhibitor 7e exhibited the highest activity (EC50 = 0.008, 0.0068, and 0.0076 μM for hRV-B14, hRV-A16, and hRV-A21, respectively) and high toxicity (CC50 = 6.1 μM). Inhibitor 7f showed good activity and low toxicity and provided the highest selectivity index (SI ≥ 4638, >3116, and >2793 for hRV-B14, hRV-A16, and hRV-A21, respectively). Furthermore, 7f showed broad-spectrum activities against various hRVs, coxsackieviruses, and other enteroviruses, such as EV-A71 and EV-D68. The binding mode of the inhibitors was investigated using 7f, and the experimental results of plaque reduction, replicon and cytotoxicity, and time-of-drug-addition assays suggested that 7f acts as a PI4KIIIβ inhibitor. The kinase inhibition activity of this series of compounds against PI4KIIIα and PI4KIIIβ was assessed, and 7f demonstrated kinase inhibition activity with an IC50 value of 0.016 μM for PI4KIIIβ, but not for PI4KIIIα (>10 μM). Therefore, 7f represents a highly potent and selective PI4KIIIβ inhibitor for the further development of antiviral therapy against hRVs or other enteroviruses.

Investigation of the General Molecular Mechanisms of Gallic Acid via Analyses of Its Transcriptome Profile

Gallic acid (GA), a phenolic compound naturally found in many plants, exhibits potential preventive and therapeutic roles. However, the underlying molecular mechanisms of its diverse biological activities remain unclear. Here, we investigated possible mechanisms of GA function through a transcriptome-based analysis using LINCS L1000, a publicly available data resource. We compared the changes in the gene expression profiles induced by GA with those induced by FDA-approved drugs in three cancer cell lines (A549, PC3, and MCF7). The top 10 drugs exhibiting high similarity with GA in their expression patterns were identified by calculating the connectivity score in the three cell lines. We specified the known target proteins of these drugs, which could be potential targets of GA, and identified 19 potential targets. Next, we retrieved evidence in the literature that GA likely binds directly to DNA polymerase β and ribonucleoside-diphosphate reductase. Although our results align with previous studies suggesting a direct and/or indirect connection between GA and the target proteins, further experimental investigations are required to fully understand the exact molecular mechanisms of GA. Our study provides insights into the therapeutic mechanisms of GA, introducing a new approach to characterizing therapeutic natural compounds using transcriptome-based analyses.

In Vitro Toxicity Screening of Fifty Complex Mixtures in HepG2 Cells

To develop the risk prediction technology for mixture toxicity, a reliable and extensive dataset of experimental results is required. However, most published literature only provides data on combinations containing two or three substances, resulting in a limited dataset for predicting the toxicity of complex mixtures. Complex mixtures may have different mode of actions (MoAs) due to their varied composition, posing difficulty in the prediction using conventional toxicity prediction models, such as the concentration addition (CA) and independent action (IA) models. The aim of this study was to generate an experimental dataset comprising complex mixtures. To identify the target complex mixtures, we referred to the findings of the HBM4EU project. We identified three groups of seven to ten components that were commonly detected together in human bodies, namely environmental phenols, perfluorinated compounds, and heavy metal compounds, assuming these chemicals to have different MoAs. In addition, a separate mixture was added consisting of seven organophosphate flame retardants (OPFRs), which may have similar chemical structures. All target substances were tested for cytotoxicity using HepG2 cell lines, and subsequently 50 different complex mixtures were randomly generated with equitoxic mixtures of EC10 levels. To determine the interaction effect, we calculated the model deviation ratio (MDR) by comparing the observed EC10 with the predicted EC10 from the CA model, then categorized three types of interactions: antagonism, additivity, and synergism. Dose-response curves and EC values were calculated for all complex mixtures. Out of 50 mixtures, none demonstrated synergism, while six mixtures exhibited an antagonistic effect. The remaining mixtures exhibited additivity with MDRs ranging from 0.50 to 1.34. Our experimental data have been formatted to and constructed for the database. They will be utilized for further research aimed at developing the combined CA/IA approaches to support mixture risk assessment.

Nanoarchitectonics of MXene Derived TiO2 /Graphene with Vertical Alignment for Achieving the Enhanced Supercapacitor Performance

Structural engineering and hybridization of heterogeneous 2D materials can be effective for advanced supercapacitor. Furthermore, architectural design of electrodes particularly with vertical construction of structurally anisotropic graphene nanosheets, can significantly enhance the electrochemical performance. Herein, MXene-derived TiO2 nanocomposites hybridized with vertical graphene is synthesized via CO2 laser irradiation on MXene/graphene oxide nanocomposite film. Instantaneous photon energy by laser irradiation enables the formation of vertical graphene structures on nanocomposite films, presenting the controlled anisotropy in free-standing film. This vertical structure enables improved supercapacitor performance by forming an open structure, increasing the electrolyte-electrode interface, and creating efficient electron transport path. In addition, the effective oxidation of MXene nanosheets by instantaneous photon energy leads to the formation of rutile TiO2 . TiO2 nanoparticles directly generated on graphene enables the effective current path, which compensates for the low conductivity of TiO2 and enables the functioning of an effective supercapacitor by utilizing its pseudocapacitive properties. The resulting film exhibits excellent specific areal capacitance of 662.9 mF cm-2 at a current density of 5 mA cm-2 . The film also shows superb cyclic stability during 40 000 repeating cycles, maintaining high capacitance. Also, the pseudocapacitive redox reaction kinetics is evaluated, showing fast redox kinetics with potential for high-performance supercapacitor applications.

All lactose-oxidizing enzymes of Pseudomonas taetrolens, a highly efficient lactobionic acid-producing microorganism, are pyrroloquinoline quinone-dependent enzymes

In previous and present studies, four enzymes (GCD1, GCD3, GCD4, and MQO1) have been found to act as lactose-oxidizing enzymes of Pseudomonas taetrolens. To investigate whether the four enzymes were the only lactose-oxidizing enzymes of P. taetrolens, we performed the inactivation of gcd1, gcd3, gcd4, and mqo1 genes in P. taetrolens. Compared to the wild-type strain, the lactobionic acid (LBA)-producing ability of P. taetrolens ∆gcd1 ∆gcd3 ∆gcd4 ∆mqo1 was only slightly decreased, implying that P. taetrolens possesses more lactose-oxidizing enzymes. Interestingly, the four lactose-oxidizing enzymes were all pyrroloquinoline quinone (PQQ)-dependent. To identify other unidentified lactose-oxidizing enzymes of P. taetrolens, we prevented the synthesis of PQQ in P. taetrolens by inactivating the genes related to PQQ synthesis such as pqqC, pqqD, and pqqE. Surprisingly, all three knocked-out strains were unable to convert lactose to LBA, indicating that all lactose-oxidizing enzymes in P. taetrolens were inactivated by eliminating PQQ synthesis. In addition, external PQQ supplementation restored the LBA production ability of P. taetrolens ∆pqqC, comparable to the wild-type strain. These results indicate that all lactose-oxidizing enzymes in P. taetrolens are PQQ-dependent.

Investigation of Laser-Induced Graphene (LIG) on a Flexible Substrate and Its Functionalization by Metal Doping for Gas-Sensing Applications

Graphene materials synthesized using direct laser writing (laser-induced graphene; LIG) make favorable sensor materials because of their large surface area, ease of fabrication, and cost-effectiveness. In particular, LIG decorated with metal nanoparticles (NPs) has been used in various sensors, including chemical sensors and electronic and electrochemical biosensors. However, the effect of metal decoration on LIG sensors remains controversial; hypotheses based on computational simulations do not always match the experimental results, and even the experimental results reported by different researchers have not been consistent. In the present study, we explored the effects of metal decorations on LIG gas sensors, with NO2 and NH3 gases as the representative oxidizing and reducing agents, respectively. To eliminate the unwanted side effects arising from metal salt residues, metal NPs were directly deposited via vacuum evaporation. Although the gas sensitivities of the sensors deteriorate upon metal decoration irrespective of the metal work function, in the case of NO2 gas, they improve upon metal decoration in the case of NH3 exposure. A careful investigation of the chemical structure and morphology of the metal NPs in the LIG sensors shows that the spontaneous oxidation of metal NPs with a low work function changes the behavior of the LIG gas sensors and that the sensors' behaviors under NO2 and NH3 gases follow different principles.

Anti-counterfeiting fiber system with near-infrared wavelength selectivity based on photothermal and thermochromic dyes

Anti-counterfeiting (ACF) technology plays a crucial role in distinguishing genuine products from counterfeits, as well as in identity verification. Moreover, it serves as a protective measure for safeguarding the rights of individuals, companies, and governments. In this study, a high-level ACF technology was developed using a color-conversion system based on the photothermal effect of near-infrared (NIR) wavelengths. Diimonium dye (DID), which is a photothermal dye, was selected because it is an NIR absorbing dye with over 98% transparency in the visible light (vis) region. Due to the photothermal properties of DID, the temperature increased to approximately 65 °C at 1064 nm and 39 °C at 808 nm, respectively. Additionally, we employed a donor-acceptor Stenhouse adduct dye, a thermochromic dye, which exhibits reversible color change due to heat (red color) and light (colorless). Our ACF technology was applied to the brand-protecting fiber utilizing the difference in photothermal temperature according to the NIR wavelength. We successfully implemented anti-counterfeit clothing using alphabet K labels that could distinguish between genuine and counterfeit products by irradiating with specific NIR wavelengths.

Facet-Controlled Growth of Hydroxyapatite for Effectively Removing Pb from Aqueous Solutions

To address the growing concerns regarding severe water pollution, effective and environmentally friendly adsorbents must be identified. In this study, we prepared hydroxyapatite (HAp, Ca10(PO4)6(OH)2) as an eco-friendly absorbent via simple precipitation and obtained rod- (r-HAp) and plate-shaped HAp (p-HAp). The approach to obtaining p-HAp involved a low pH titration rate, promoting growth along the c-axis due to the adsorption of OH- on the (110) facet. Conversely, r-HAp was obtained by maintaining a high concentration of OH- during the initial stage through rapid pH titration, leading to a stronger restrictive effect on the growth of positively charged a(b)-planes. p-HAp demonstrated superior adsorption capacity, removing Pb through dissolution and recrystallization, achieving an impressive 625 mg/g within a 60 min reaction time compared to r-HAp. Our findings afford insights into the Pb removal mechanisms of HAp with different morphologies and can aid in the development of water purification strategies against heavy metal contamination.

Engineering of cell-surface receptors for analysis of receptor internalization and detection of receptor-specific glycosylation

The epidermal growth factor receptor (EGFR) is a cell-surface glycoprotein that is involved mainly in cell proliferation. Overexpression of this receptor is intimately related to the development of a broad spectrum of tumors. In addition, glycans linked to the EGFR are known to affect its EGF-induced activation. Because of the pathophysiological significance of the EGFR, we prepared a fluorescently labeled EGFR (EGFR128-AZDye 488) on the cell surface by employing the genetic code expansion technique and bioorthogonal chemistry. EGFR128-AZDye 488 was initially utilized to investigate time-dependent endocytosis of the EGFR in live cells. The results showed that an EGFR inhibitor and antibody suppress endocytosis of the EGFR promoted by the EGF, and that lectins recognizing glycans of the EGFR do not enhance EGFR internalization into cells. Observations made in studies of the effects of appended glycans on the entry of the EGFR into cells indicate that a de-sialylated or de-fucosylated EGFR is internalized into cells more efficiently than a wild-type EGFR. Furthermore, by using the FRET-based imaging method of cells which contain an EGFR linked to AZDye 488 (a FRET donor) and cellular glycans labeled with rhodamine (a FRET acceptor), sialic acid residues attached to the EGFR were specifically detected on the live cell surface. Taken together, the results suggest that a fluorescently labeled EGFR will be a valuable tool in studies aimed at gaining an understanding of cellular functions of the EGFR.

Long and Short-Term Effect of mTOR Regulation on Cerebral Organoid Growth and Differentiations

BACKGROUND

The mammalian target of rapamycin (mTOR) signaling is critical for the maintenance and differentiation of neurogenesis, and conceivably for many other brain developmental processes. However, in vivo studies of mTOR functions in the brain are often hampered due to the essential role of the associated signaling in brain development.

METHODS

We monitored the long- and short-term effects of mTOR signaling regulation on cerebral organoids growth, differentiation and function using an mTOR inhibitor (everolimus) and an mTOR activator (MHY1485).

RESULTS

Short-term treatment with MHY1485 induced faster organoid growth and differentiation, while long-term treatment induced the maturation of cerebral organoids.

CONCLUSION

These data suggest that the optimal activity of mTOR is crucial in maintaining normal brain development, and its role is not confined to the early neurogenic phase of brain development.

Auxetic Photonic Patterns with Ultrasensitive Mechanochromism

Photonic crystals with mechanochromic properties are currently under intensive study to provide intuitive colorimetric detection of strains for various applications. However, the sensitivity of color change to strain is intrinsically limited, as the degree of deformation determines the wavelength shift. To overcome this limitation, auxetic photonic patterns that exhibit ultra-sensitive mechanochromism are designed. These patterns have a regular arrangement of cuts that expand to accommodate the strain, while the skeletal framework undergoes torsional deformation. Elastic photonic crystals composed of a non-close-packed array of colloidal particles are embedded in the cut area of the auxetic patterns. As the cut area amplifies the strains, the elastic photonic crystals show significant color change even for small total strains. The degree of local-strain amplification, or sensitivity of color change, is controllable by adjusting the width of cuts in the auxetic framework. In this work, a maximum sensitivity of up to 60 nm/% is achieved, which is 20 times higher than bulk films. It is believed that the auxetic photonic patterns with ultra-sensitive mechanochromism will provide new opportunities for the pragmatic use of mechanochromic materials in various fields, including structural health monitoring.

Late-Stage C-H Activation of Drug (Derivative) Molecules with Pd(ll) Catalysis

This review comprehensively analyses representative examples of Pd(II)-catalyzed late-stage C-H activation reactions and demonstrates their efficacy in converting C-H bonds at multiple positions within drug (derivative) molecules into diverse functional groups. These transformative reactions hold immense potential in medicinal chemistry, enabling the efficient and selective functionalization of specific sites within drug molecules, thereby enhancing their pharmacological activity and expanding the scope of potential drug candidates. Although notable articles have focused on late-stage C-H functionalization reactions of drug-like molecules using transition-metal catalysts, reviews specifically focusing on late-stage C-H functionalization reactions of drug (derivative) molecules using Pd(II) catalysts are required owing to their prominence as the most widely utilized metal catalysts for C-H activation and their ability to introduce a myriad of functional groups at specific C-H bonds. The utilization of Pd-catalyzed C-H activation methodologies demonstrates impressive success in introducing various functional groups, such as cyano (CN), fluorine (F), chlorine (Cl), aromatic rings, olefin, alkyl, alkyne, and hydroxyl groups, to drug (derivative) molecules with high regioselectivity and functional-group tolerance. These breakthroughs in late-stage C-H activation reactions serve as invaluable tools for drug discovery and development, thereby offering strategic options to optimize drug candidates and drive the exploration of innovative therapeutic solutions.

Recent Developments in Atomic Layer Deposition of Functional Overlayers in Perovskite Solar Cells

Over the last decade, research in organic-inorganic lead halide perovskite solar cells (PSCs) has gathered unprecedented momentum, putting the technology on the brink of full-scale commercialization. A wide range of strategies have been implemented for enhancing the power conversion efficiency of devices and modules, as well as improving stability toward high levels of irradiation, temperature, and humidity. Another key element in the path to commercialization is the scalability of device manufacturing, which requires large-scale deposition of conformal layers without compromising the delicate structure of the perovskite film. In this context, atomic layer deposition (ALD) tools excel in depositing high-quality conformal films with precise control of film composition and thickness over large areas at relatively low processing temperatures. In this commentary, we will briefly outline recent progress in PSC technology enabled by ALD tools, focusing on layers deposited above the absorber layer. These interlayers include charge transport layers, passivation layers, buffer layers, and encapsulation techniques. Additionally, we will discuss some of the challenges and potential avenues for research in PSC technology underpinned by ALD tools.

A Comparative Inflammation-on-a-Chip with a Complete 3D Interface: Pharmacological Applications in COPD-Induced Neutrophil Migration

Chronic obstructive pulmonary disease (COPD) is a slow-progressing inflammatory lung disease that is associated with high mortality and disability. There is a lack of appropriate preclinical models of COPD, which hampers drug discovery efforts. Herein, a comparative inflammation-on-a-chip (IoC) is developed with a complete 3D interface without the formation of any micropillar and phaseguide structures that replicated chemoattractant-induced neutrophil transendothelial migration (NTEM), a key feature of COPD. The IoC model is used to evaluate the pharmacological effects of CXCR2 inhibitors (MK-7123, AZD5069, and SB225002) on the migration of neutrophil-like cells in the presence of plasma samples from patients with COPD. This is the first study to evaluate inhibitors of CXCR2-dependent NTEM in a comparative IoC model that mimics the physiological 3D microenvironment, consisting of an endothelial barrier, extracellular compartment, and inflammatory conditions. This IoC model will be useful to investigate COPD severity using patient samples, and will aid basic and translational research involving NTEM.

Self-healing polymers for surface scratch regeneration

Recently, there has been a significant increase in academic and industrial interest in self-healing polymers (SHPs) due to their remarkable ability to regenerate scratched surfaces and materials of astronomical significance. Scientists have been inspired by the magical repairing mechanism of the living world. They transformed the fiction of self-healing into reality by designing engrossing polymeric materials that could self-repair mechanical abrasions repeatedly. As a result, the durability of the materials is remarkably improved. Thus, the idea of studying SHPs passively upholds economic and environmental sustainability. However, the critical areas of self-healing (including healing efficiency, healing mechanism, and thermo-mechanical property changes during healing) are under continuous scientific improvisation. This review highlights recent notable advances of SHPs for application in regenerating scratched surfaces with various distinctive underlying mechanisms. The primary focus of the work is aimed at discussing the impact of SHPs on scratch-healing technology. Beyond that, insights regarding scratch testing, methods of investigating polymer surfaces, wound depths, the addition of healing fillers, and the environmental conditions maintained during the healing process are reviewed thoroughly. Finally, broader future perspectives on the challenges and prospects of SHPs in healing surface scratches are discussed.

Recent Advances in the Development of Sulfamoyl-Based Hepatitis B Virus Nucleocapsid Assembly Modulators

Hepatitis B virus (HBV) is the primary contributor to severe liver ailments, encompassing conditions such as cirrhosis and hepatocellular carcinoma. Globally, 257 million people are affected by HBV annually and 887,000 deaths are attributed to it, representing a substantial health burden. Regrettably, none of the existing therapies for chronic hepatitis B (CHB) have achieved satisfactory clinical cure rates. This issue stems from the existence of covalently closed circular DNA (cccDNA), which is difficult to eliminate from the nucleus of infected hepatocytes. HBV genetic material is composed of partially double-stranded DNA that forms complexes with viral polymerase inside an icosahedral capsid composed of a dimeric core protein. The HBV core protein, consisting of 183 to 185 amino acids, plays integral roles in multiple essential functions within the HBV replication process. In this review, we describe the effects of sulfamoyl-based carboxamide capsid assembly modulators (CAMs) on capsid assembly, which can suppress HBV replication and disrupt the production of new cccDNA. We present research on classical, first-generation sulfamoyl benzocarboxamide CAMs, elucidating their structural composition and antiviral efficacy. Additionally, we explore newly identified sulfamoyl-based CAMs, including sulfamoyl bicyclic carboxamides, sulfamoyl aromatic heterocyclic carboxamides, sulfamoyl aliphatic heterocyclic carboxamides, cyclic sulfonamides, and non-carboxamide sulfomoyl-based CAMs. We believe that certain molecules derived from sulfamoyl groups have the potential to be developed into essential components of a well-suited combination therapy, ultimately yielding superior clinical efficacy outcomes in the future.

New Heteroleptic Germanium Precursors for GeO2 Thin Films by Atomic Layer Deposition

This study describes the synthesis of 12 new germanium complexes containing β-diketonate and/or N-alkoxy carboxamidate-type ligands as precursors for GeO2 through atomic layer deposition (ALD). A series of Ge(β-diketonate)Cl complexes such as Ge(acac)Cl (1) and Ge(tmhd)Cl (2) were synthesized by using acetylacetone (acacH) and 2,2,6,6-tetramethyl-3,5-heptanedione (tmhdH). N-Alkoxy carboxamidate-type ligands such as N-methoxypropanamide (mpaH), N-methoxy-2,2-dimethylpropanamide (mdpaH), N-ethoxy-2-methylpropanamide (empaH), N-ethoxy-2,2-dimethylpropanamide (edpaH), and N-methoxybenzamide (mbaH) were used to afford further substituted complexes Ge(acac)(mpa) (3), Ge(acac)(mdpa) (4), Ge(acac)(empa) (5), Ge(acac)(edpa) (6), Ge(acac)(mba) (7), Ge(tmhd)(mpa) (8), Ge(tmhd)(mdpa) (9), Ge(tmhd)(empa) (10), Ge(tmhd)(edpa) (11), and Ge(tmhd)(mba) (12), respectively. Thermogravimetric analysis curves, which mostly exhibited single-step weight losses, were used to determine the evaporation properties of complexes 1-12. Interestingly, liquid complex 2 has no residue at 198 °C and therefore exhibits excellent vaporization properties and high volatility. Single-crystal X-ray diffraction studies of 1 and 7 demonstrated that the complexes had monomeric molecular structures with germanium chelated by the oxygen atoms of one or two bidentate ligands, respectively. An ALD process was developed for the growth of GeO2 using Ge(tmhd)Cl (2) as a new precursor and H2O2 as an oxidant. This study demonstrates the achievement of self-limiting growth of GeO2 films by varying the duration of injection/purge, with an observed ALD window at deposition temperatures ranging from 300 to 350 °C. The saturated growth per cycle of the GeO2 film was determined as 0.27 Å/cycle at a deposition temperature of 300 °C. The deposited films were observed to be amorphous consisting of GeO2.

Single-cell RNA Sequencing Reveals Novel Cellular Factors for Response to Immunosuppressive Therapy in Aplastic Anemia

Aplastic anemia (AA) is a lethal hematological disorder; however, its pathogenesis is not fully understood. Although immunosuppressive therapy (IST) is a major treatment option for AA, one-third of patients do not respond to IST and its resistance mechanism remains elusive. To understand AA pathogenesis and IST resistance, we performed single-cell RNA sequencing (scRNA-seq) of bone marrow (BM) from healthy controls and patients with AA at diagnosis. We found that CD34+ early-stage erythroid precursor cells and PROM1+ hematopoietic stem cells were significantly depleted in AA, which suggests that the depletion of CD34+ early-stage erythroid precursor cells and PROM1+ hematopoietic stem cells might be one of the major mechanisms for AA pathogenesis related with BM-cell hypoplasia. More importantly, we observed the significant enrichment of CD8+ T cells and T cell-activating intercellular interactions in IST responders, indicating the association between the expansion and activation of T cells and the positive response of IST in AA. Taken together, our findings represent a valuable resource offering novel insights into the cellular heterogeneity in the BM of AA and reveal potential biomarkers for IST, building the foundation for future precision therapies in AA.

Quantitative and Qualitative Analysis of Neurotransmitter and Neurosteroid Production in Cerebral Organoids during Differentiation

In the human brain, neurophysiological activity is modulated by the movement of neurotransmitters and neurosteroids. To date, the similarity between cerebral organoids and actual human brains has been evaluated using comprehensive multiomics approaches. However, a systematic analysis of both neurotransmitters and neurosteroids from cerebral organoids has not yet been reported. Here, we performed quantitative and qualitative assessments of neurotransmitters and neurosteroids over the course of cerebral organoid differentiation. Our multiomics approaches revealed that the expression levels of neurotransmitter-related proteins and RNA, including neurosteroids, increase as cerebral organoids mature. We also found that the electrophysiological activity of human cerebral organoids increases in tandem with the expression levels of both neurotransmitters and neurosteroids. Our study demonstrates that the expression levels of neurotransmitters and neurosteroids can serve as key factors in evaluating the maturity and functionality of human cerebral organoids.

Polyether-based waterborne synergists: effect of polymer topologies on pigment dispersion

Control of polymer topologies is essential to determine their unique physical properties and potential applications. The polymer topologies can have a critical effect on pigment dispersion owing to their unique architectures; however, studies using polymer topologies on pigment dispersion in aqueous systems are scarce. Thus, this study proposes various topologies of polyether-based waterborne synergists, such as linear, hyperbranched, and branched cyclic structures. Specifically, we applied branched types of polyglycidols (PGs) as a synergist to provide polymer topology-dependent dispersibility for the surface-modification of Red 170 particles through adsorption and steric hindrance. The topology-controlled PG synergists (PGSs) were successfully prepared by post-polymerization modification with phthalimide and benzoyl groups. Particularly, the branched types of PGSs, branched cyclic PGS (bc-PGS), and hyperbranched PGS (hb-PGS) exhibited improved dispersibility through adsorption on top of the pigment, interaction between dispersant (BYK 190) and pigment, and steric effect. Surprisingly, hb-PGS conferred the Red 170 pigment particles with superior storage stability than that of bc-PGS despite their similar structural features. This study suggests the widespread potential application of PGSs as waterborne synergists for various dispersion applications.

A Multifunctional Interlocked Binder with Synergistic In Situ Covalent and Hydrogen Bonding for High-Performance Si Anode in Li-ion Batteries

Silicon has garnered significant attention as a promising anode material for high-energy density Li-ion batteries. However, Si can be easily pulverized during cycling, which results in the loss of electrical contact and ultimately shortens battery lifetime. Therefore, the Si anode binder is developed to dissipate the enormous mechanical stress of the Si anode with enhanced mechanical properties. However, the interfacial stability between the Si anode binder and Cu current collector should also be improved. Here, a multifunctional thiourea polymer network (TUPN) is proposed as the Si anode binder. The TUPN binder provides the structural integrity of the Si anode with excellent tensile strength and resilience due to the epoxy-amine and silanol-epoxy covalent cross-linking, while exhibiting high extensibility from the random coil chains with the hydrogen bonds of thiourea, oligoether, and isocyanurate moieties. Furthermore, the robust TUPN binder enhances the interfacial stability between the Si anode and current collector by forming a physical interaction. Finally, the facilitated Li-ion transport and improved electrolyte wettability are realized due to the polar oligoether, thiourea, and isocyanurate moieties, respectively. The concept of this work is to highlight providing directions for the design of polymer binders for next-generation batteries.

Aminal-Linked Covalent Organic Frameworks with hxl-a and Quasi-hcb Topologies for Efficient C2 H6 /C2 H4 Separation

In reticular chemistry, topology is a powerful concept for defining the structures of covalent organic frameworks (COFs). However, due to the lack of diversity in the symmetry and reaction stoichiometry of the monomers, only 5% of the two-dimensional topologies have been reported to be COFs. To overcome the limitations of COF connectivity and pursue novel topologies in COF structures, two aminal-linked COFs, KUF-2 and KUF-3, are prepared, with dumbbell-shaped secondary building units. Linear dialdehydes and piperazine are condensed at a ratio of 1:2 to construct an aminal linkage, leading to unreported hxl-a (KUF-2) and quasi-hcb (KUF-3) structures. Notably, KUF-3 displays top-tier C2 H6 /C2 H4 selectivity and C2 H6 uptake at 298 K, outperforming most porous organic materials. The intrinsic aromatic ring-rich and Lewis basic pore environments, and appropriate pore widths enable the selective adsorption of C2 H6 , as confirmed by Grand Canonical Monte Carlo simulations. Dynamic breakthrough curves revealed that C2 H6 can be selectively separated from a gas mixture of C2 H6 and C2 H4 . This study suggests that topology-based design of aminal-COFs is an effective strategy for expanding the field of reticular chemistry and provides the facile integration of strong Lewis basic sites for selective C2 H6 /C2 H4 separation.

Ultrathin Metal Film on Graphene for Percolation-Threshold-Limited Thermal Emissivity Control

Translucent Au/graphene hybrid films are shown to be effective in reducing thermal emission from the underlying surfaces when the deposition thickness of Au is close to the percolation threshold. The critical Au deposition thickness for an abrupt change in emissivity is reduced from 15 nm (Si substrate) to a percolation-threshold-limited thickness of 8.5 nm (graphene/Si substrate) because of the chemical inertness of graphene leading to the deposited Au atoms forming a thin, crystalline layer. The effect of the graphene layer on the optical properties of the hybrid film is highlighted by a drastic increase in infrared absorptivity, whereas the visible absorptivity is marginally affected by the presence of a graphene layer. The level of thermal emission from the Au/graphene hybrid films with the percolation-threshold-limited Au thickness is stable even with high background temperatures of up to 300 °C and mechanical strains of ≈4%. As an example of a thermal management application, an anti-counterfeiting device is demonstrated; thermal-camouflage-masked text fabricated with an Au/graphene hybrid film is discernible only using a thermographic camera. Ultrathin metal film assisted by a graphene layer will provide a facile platform for thermal management with semi-transparency, flexibility, and transferability to arbitrary surfaces.

Morphology and Performance Enhancement through the Strong Passivation Effect of Amphoteric Ions in Tin-based Perovskite Solar Cells

Despite the optoelectronic similarities between tin and lead halide perovskites, the performance of tin-based perovskite solar cells remains far behind, with the highest reported efficiency to date being ≈14%. This is highly correlated to the instability of tin halide perovskite, as well as the rapid crystallization behavior in perovskite film formation. In this work, l-Asparagine as a zwitterion plays a dual role in controlling the nucleation/crystallization process and improving the morphology of perovskite film. Furthermore, tin perovskites with l-Asparagine show more favorable energy-level matching, enhancing the charge extraction and minimizing the charge recombination, leading to an enhanced power conversion efficiency of 13.31% (from 10.54% without l-Asparagine) with remarkable stability. These results are also in good agreement with the density functional theory calculations. This work not only provides a facile and efficient approach to controlling the crystallization and morphology of perovskite film but also offers guidelines for further improved performance of tin-based perovskite electronic devices.

Fabrication of Tri-Directional Poly(2,5-benzimidazole) Membrane Using Direct Casting for Vanadium Redox Flow Battery

In vanadium redox flow batteries (VRFBs), simultaneously achieving high proton conductivity, low vanadium-ion permeability, and outstanding chemical stability using electrolyte membranes is a significant challenge. In this study, we report the fabrication of a tri-directional poly(2,5-benzimidazole) (T-ABPBI) membrane using a direct casting method. The direct-cast T-ABPBI (D-T-ABPBI) membrane was fabricated by modifying the microstructure of the membrane while retaining the chemical structure of ABPBI, having outstanding chemical stability. The D-T-ABPBI membrane exhibited lower crystallinity and an expanded free volume compared to the general solvent-cast T-ABPBI (S-T-ABPBI) membrane, resulting in enhanced hydrophilic absorption capabilities. Compared to the S-T-ABPBI membrane, the enhanced hydrophilic absorption capability of the D-T-ABPBI membrane resulted in a decrease in the specific resistance (the area-specific resistance of S-T-ABPBI and D-T-ABPBI membrane is 1.75 and 0.98 Ωcm2, respectively). Additionally, the D-T-ABPBI membrane showed lower vanadium permeability (3.40 × 10-7 cm2 min-1) compared to that of Nafion 115 (5.20 × 10-7 cm2 min-1) due to the Donnan exclusion effect. Owing to the synergistic effects of these properties, the VRFB assembled with D-T-ABPBI membrane had higher or equivalent coulomb efficiencies (>97%) and energy efficiencies (70-91%) than Nafion 115 at various current densities (200-40 mA cm-2). Furthermore, the D-T-ABPBI membrane exhibited stable performance for over 300 cycles at 100 mA cm-2, suggesting its outstanding chemical stability against the highly oxidizing VO2+ ions during practical VRFB operation. These results indicate that the newly fabricated D-T-ABPBI membranes are promising candidates for VRFB application.

Intramolecular cyclization of N-cyano sulfoximines by N-CN bond activation

Metal-free halogenated anhydrides promote the intramolecular cyclization of N-cyano sulfoximines. Trifluoro- or trichloroacetic anhydride (TFAA or TCAA, respectively) activate the N-cyano groups of N-cyano sulfoximines, leading to the intramolecular cyclization of 2-benzamide-N-cyano sulfoximines 1. This method results in excellent yields of thiadiazinone 1-oxides 2. A full intramolecular cyclization pattern was suggested by (i) labeling experiments with 13C, (ii) isolating of N-trifluoroacetyl sulfoximine 1ac, and (iii) confirming the generation of the intermediate 1ad by LC/MS analysis.

Trifluoromethyl-Substituted Conjugated Random Terpolymers Enable High-Performance Small and Large-Area Organic Solar Cells Using Halogen-Free Solvent

The advancement of non-fullerene acceptors with crescent-shaped geometry has led to the need for polymer donor improvements. Additionally, there is potential to enhance the photovoltaic parameters in high-efficiency organic solar cells (OSCs). The random copolymerization method is a straightforward and effective strategy to further optimize photoactive morphology and enhance device performance. However, finding a suitable third component in terpolymers remains a crucial challenge. In this study, a series of terpolymer donors (PTF3, PTF5, PTF10, PTF20, and PTF50) is synthesized by introducing varying amounts of the trifluoromethyl-substituted unit (CF3) into the PM6 polymer backbone. Even subtle changes in the CF3 content can significantly enhance all the photovoltaic parameters due to the optimized energy levels, molecular aggregation/miscibility, and bulk-heterojunction morphology of the photoactive materials. Thus, the best binary OSC based on the PTF5:Y6-BO achieves an outstanding power conversion efficiency (PCE) of 18.2% in the unit cell and a PCE of 11.6% in the sub-module device (aperture size: 54.45 cm2 ), when using halogen-free solvent o-xylene. This work showcases the remarkable potential of the easily accessible CF3 unit as a key constituent in the construction of terpolymer donors in high-performance OSCs.

Optimized conditions for gene transduction into primary immune cells using viral vectors

Chimeric antigen receptor (CAR) T cell therapy has emerged as a promising modality for anti-cancer treatment. Its efficacy is quite remarkable in hematological tumors. Owing to their excellent clinical results, gene- modified cell therapies, including T cells, natural killer (NK) cells, and macrophages, are being actively studied in both academia and industry. However, the protocol to make CAR immune cells is too complicated, so it is still unclear how to efficiently produce the potent CAR immune cells. To manufacture effective CAR immune cells, we need to be aware of not only how to obtain highly infective viral particles, but also how to transduce CAR genes into immune cells. In this paper, we provide detailed information on spinoculation, which is one of the best known protocols to transduce genes into immune cells, in a methodological view. Our data indicate that gene transduction is significantly dependent on speed and duration of centrifugation, concentration and number of viral particles, the concentration of polybrene, and number of infected immune cells. In addition, we investigated on the optimal polyethylene glycol (PEG) solution to concentrate the viral supernatant and the optimized DNA ratios transfected into 293T cells to produce high titer of viral particles. This study provides useful information for practical production of the gene-modified immune cells using viral vectors.

Mesoporous Polydopamine-Encapsulated Fluorescent Nanodiamonds: A Versatile Platform for Biomedical Applications

Fluorescent nanodiamonds (FNDs) are versatile nanomaterials with promising properties. However, efficient functionalization of FNDs for biomedical applications remains challenging. In this study, we demonstrate mesoporous polydopamine (mPDA) encapsulation of FNDs. The mPDA shell is generated by sequential formation of micelles via self-assembly of Pluronic F127 (F127) with 1,3,5-trimethyl benzene (TMB) and composite micelles via oxidation and self-polymerization of dopamine hydrochloride (DA). The surface of the mPDA shell can be readily functionalized with thiol-terminated methoxy polyethylene glycol (mPEG-SH), hyperbranched polyglycerol (HPG), and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS). The PEGylated FND@mPDA particles are efficiently taken up by, and employed as a fluorescent imaging probe for, HeLa cells. HPG-functionalized FND@mPDA is conjugated with an amino-terminated oligonucleotide to detect microRNA via hybridization. Finally, the increased surface area of the mPDA shell permits efficient loading of doxorubicin hydrochloride. Further modification with TPGS increases drug delivery efficiency, resulting in high toxicity to cancer cells.

Spherical Sulfur-Infiltrated Carbon Cathode with a Tunable Poly(3,4-ethylenedioxythiophene) Layer for Lithium-Sulfur Batteries

Li-S batteries have received significant attention owing to their high energy density, nontoxicity, low cost, and eco-friendliness. However, the dissolution of lithium polysulfide during the charge/discharge process and its extremely low electron conductivity hinder practical applications of Li-S batteries. Herein, we report a sulfur-infiltrated carbon cathode material with a spherical morphology and conductive polymer coating. The material was produced via a facile polymerization process that forms a robust nanostructured layer and physically prevents the dissolution of lithium polysulfide. The thin double layer composed of carbon and poly(3,4-ethylenedioxythiophene) provides sufficient space for sulfur storage and effectively prevents the elution of polysulfide during continuous cycling, thereby playing an essential role in increasing the sulfur utilization rate and significantly improving the electrochemical performance of the battery. Sulfur-infiltrated hollow carbon spheres with a conductive polymer layer demonstrate a stable cycle life and reduced internal resistance. The as-fabricated battery demonstrated an excellent capacity of 970 mA h g^-1 at 0.5 C and a stable cycle performance, exhibiting ∼78% of the initial discharge capacity after 50 cycles. This study provides a promising approach to significantly improve the electrochemical performance of Li-S batteries and render them as valuable and safe energy devices for large-scale energy storage systems.

Novel Volatile Heteroleptic Barium Complexes Using Tetradentate Ligand and β-Diketonato Ligand

Novel barium heteroleptic complexes were synthesized through the substitution of the bis(trimethylsilyl)amide of Ba(btsa)₂·2DME with aminoalkoxide and β-diketonate ligands. Compounds [Ba(ddemap)(tmhd)]₂ (1) and [Ba(ddemmp)(tmhd)]₂ (2) were obtained and analyzed through Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and elemental analysis (ddemapH = 1-(dimethylamino)-5-((2-(dimethylamino)ethyl) (methyl)amino)pentan-3-ol and ddemmpH = 1-(dimethylamino)-5-((2-(dimethylamino)ethyl) (methyl)amino)-3-methylpentan-3-ol). In single-crystal X-ray crystallography, complex 1 exhibited a dimeric structure with μ₂-O bonds of the ddemap ligand. All complexes exhibited high volatility and could be sublimed under reduced pressure (0.5 Torr) at 160 °C, indicating that these complexes are promising candidates as atomic layer deposition or chemical vapor deposition precursors for the growth of barium-containing thin films.

MeCP2 dysfunction prevents proper BMP signaling and neural progenitor expansion in brain organoid

OBJECTIVES

Sporadic mutations in MeCP2 are a hallmark of Rett syndrome (RTT). Many RTT brain organoid models have exhibited pathogenic phenotypes such as decreased spine density and small size of soma with altered electrophysiological signals. However, previous models are mainly focused on the phenotypes observed in the late phase and rarely provide clues for the defect of neural progenitors which generate different types of neurons and glial cells.

METHODS

We newly established the RTT brain organoid model derived from MeCP2-truncated iPS cells which were genetically engineered by CRISPR/Cas9 technology. By immunofluorescence imaging, we studied the development of NPC pool and its fate specification into glutamatergic neurons or astrocytes in RTT organoids. By total RNA sequencing, we investigated which signaling pathways were altered during the early brain development in RTT organoids.

RESULTS

Dysfunction of MeCP2 caused the defect of neural rosette formation in the early phase of cortical development. In total transcriptome analysis, BMP pathway-related genes are highly associated with MeCP2 depletion. Moreover, levels of pSMAD1/5 and BMP target genes are excessively increased, and treatment of BMP inhibitors partially rescues the cell cycle progression of neural progenitors. Subsequently, MeCP2 dysfunction reduced the glutamatergic neurogenesis and induced overproduction of astrocytes. Nevertheless, early inhibition of BMP pathway rescued VGLUT1 expression and suppressed astrocyte maturation.

INTERPRETATION

Our results demonstrate that MeCP2 is required for the expansion of neural progenitor cells by modulating BMP pathway at early stages of development, and this influence persists during neurogenesis and gliogenesis at later stages of brain organoid development.

Electrocatalytic Reactions for Converting CO2 to Value-Added Products: Recent Progress and Emerging Trends

Carbon dioxide (CO₂) emissions are an important environmental issue that causes greenhouse and climate change effects on the earth. Nowadays, CO₂ has various conversion methods to be a potential carbon resource, such as photocatalytic, electrocatalytic, and photo-electrocatalytic. CO₂ conversion into value-added products has many advantages, including facile control of the reaction rate by adjusting the applied voltage and minimal environmental pollution. The development of efficient electrocatalysts and improving their viability with appropriate reactor designs is essential for the commercialization of this environmentally friendly method. In addition, microbial electrosynthesis which utilizes an electroactive bio-film electrode as a catalyst can be considered as another option to reduce CO₂. This review highlights the methods which can contribute to the increase in efficiency of carbon dioxide reduction (CO₂R) processes through electrode structure with the introduction of various electrolytes such as ionic liquid, sulfate, and bicarbonate electrolytes, with the control of pH and with the control of the operating pressure and temperature of the electrolyzer. It also presents the research status, a fundamental understanding of carbon dioxide reduction reaction (CO₂RR) mechanisms, the development of electrochemical CO₂R technologies, and challenges and opportunities for future research.

Synthesis and Characterization of Tungsten Amide Complexes for the Deposition of Tungsten Disulfide Thin Films

To substitute corrosive halogen ligands, we designed and synthesized novel tungsten complexes containing amido ligands, W(DMEDA)₃ (1) and W(DEEDA)₃ (2) (DMEDA = N,N'-dimethylethylenediamido; DEEDA = N,N'-diethylethylenediamido). Complexes 1 and 2 were characterized by ¹H NMR, ¹³C NMR, FT-IR, and elemental analysis. The pseudo-octahedral molecular structure of 1 was confirmed by single-crystal X-ray crystallography. The thermal properties of 1 and 2 were analyzed by thermogravimetric analysis (TGA), which confirmed that the precursors were volatile and exhibited adequate thermal stability. Additionally, the WS₂ deposition test was performed using 1 in thermal chemical vapor deposition (thermal CVD). Further analysis of the surface of the thin films was conducted using Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS).

Tuning Hydrophilicity of Aluminum MOFs by a Mixed-Linker Strategy for Enhanced Performance in Water Adsorption-Driven Heat Allocation Application

Water adsorption-driven heat transfer (AHT) technology has emerged as a promising solution to address crisis of the global energy consumption and environmental pollution of current heating and cooling processes. Hydrophilicity of water adsorbents plays a decisive role in these applications. This work reports an easy, green, and inexpensive approach to tuning the hydrophilicity of metal-organic frameworks (MOFs) by incorporating mixed linkers, isophthalic acid (IPA), and 3,5-pyridinedicarboxylic acid (PYDC), with various ratios in a series of Al-xIPA-(100-x)PYDC (x: feeding ratio of IPA) MOFs. The designed mixed-linkers MOFs show a variation of hydrophilicity along the fraction of the linkers. Representative compounds with a proportional mixed linker ratio denoted as KMF-2, exhibit an S-shaped isotherm, an excellent coefficient of performance of 0.75 (cooling) and 1.66 (heating) achieved with low driving temperature below 70 °C which offers capability to employ solar or industrial waste heat, remarkable volumetric specific energy capacity (235 kWh m^-3 ) and heat-storage capacity (330 kWh m^-3 ). The superiority of KMF-2 to IPA or PYDC-containing single-linker MOFs (CAU-10-H and CAU-10pydc, respectively) and most of benchmark adsorbents illustrate the effectiveness of the mixed-linker strategy to design AHT adsorbents with promising performance.

Plastic Shavings by Laser: Peeling Porous Graphene Springs for Multifunctional All-Carbon Applications

Manufacturing strategies to create three-dimensional (3D) structures with multifunctional nanomaterials are of intense interest for fabricating building blocks in many electromechanical applications. A coil spring composed of graphene provides an important step toward the realization of all-carbon devices, as it is one of the essential elements for a wide range of systems. In this connection, here an unprecedented fabrication strategy to create a new type of 3D coil spring composed of laser-induced graphene springs (LIG-S) which is spontaneously produced via the pyrolytic jetting technique, is presented. Similar to wood or metal shavings observed in traditional machining processes, a pair of LIG-S with two opposite chiralities and controllable macroscopic dimensions is produced by a single scanning of a focused continuous-wave (CW) laser on a polyimide (PI) substrate. The resulting LIG-S, plastic shavings by laser, exhibits sufficient mechanical and electrical properties to enable many applications including strain-tolerant spring electrodes, antennas, supercapacitors, gas sensors, and luminescent filaments under extreme conditions. Without using any conventional fabrication techniques or other labor-intensive, time-consuming, and expensive processes, this novel approach enables a high-throughput mass production of macro-, micro-, and nanoscale featured LIG-S that can be manufactured within seconds to realize many open opportunities in all-carbon electromechanical systems.

Synthesis of Mononuclear Strontium Complexes with Polyether and β-Diketonato Ligands

Strontium β-diketonate complexes were synthesized by the substitution reaction of the bis(trimethylsilyl) amide of Sr(btsa)₂·2DME with an ethereal group and β-diketonate ligands. The compounds [Sr(tmge)(btsa)]₂ (1), [Sr(tod)(btsa)]₂ (2), Sr(tmgeH)(tfac)₂ (3), Sr(tmgeH)(acac)₂ (4), Sr(tmgeH)(tmhd)₂ (5), Sr(todH)(tfac)₂ (6), Sr(todH)(acac)₂ (7), Sr(todH)(tmhd)₂ (8), Sr(todH)(hfac)₂ (9), Sr(dmts)(hfac)₂ (10), [Sr(mee)(tmhd)₂]₂ (11), and Sr(dts)(hfac)₂·DME (12) were obtained and analyzed by various techniques, including FT-IR, NMR, TGA (thermogravimetric analyses), and elemental analysis. Complexes 1, 3, 8, 9, 10, 11, and 12 were further structurally confirmed by single-crystal X-ray crystallography, where complexes 1 and 11 showed dimeric structures with μ₂-O bonds of ethereal groups or tmhd ligands, and complexes 3, 8, 9, 10, and 12 displayed monomeric structures. Interestingly, compounds 10 and 12, which preceded trimethylsilylation of the coordinating ethereal alcohols such as tmhgeH and meeH in the presence of HMDS as by-products due to highly increasing acidity of them, originated from electron-withdrawing two hfac ligands.

Rationally Designed Eco-Friendly Solvent System for High-Performance, Large-Area Perovskite Solar Cells and Modules

The important but remained issue to be addressed to achieve the mass production of perovskite solar modules include a large-area fabrication of high-quality perovskite film with eco-friendly, viable production methods. Although several efforts are made to achieve large-area fabrication of perovskite, the development of eco-friendly solvent system, which is precisely designed to be fit to scale-up methods are still challenging. Herein, this work develops the eco-friendly solvent/co-solvent system to produce a high-quality perovskite layer with a bathing in eco-friendly antisolvent. The new co-solvent/additive, methylsulfonylmethane (MSM), efficiently improves the overall solubility and has a suitable binding strength to the perovskite precursor, resulting in a high-quality perovskite film with antisolvent bathing method in large area. The resultant perovskite solar cells showed high power conversion efficiency of over 24% (in reverse scan), with a good long-term stability under continuous light illumination or damp-heat condition. MSM is also beneficial to produce a perovskite layer at low-temperature or high-humidity. MSM-based solvent system is finally applied to large-area, resulting in highly efficiency perovskite solar modules with PCE of 19.9% (by aperture) or 21.2% (by active area) in reverse scan. These findings contribute to step forward to a mass production of perovskite solar modules with eco-friendly way.

Evaluation of Antiviral Activity of Gemcitabine Derivatives against Influenza Virus and Severe Acute Respiratory Syndrome Coronavirus 2

Gemcitabine is a nucleoside analogue of deoxycytidine and has been reported to be a broad-spectrum antiviral agent against both DNA and RNA viruses. Screening of a nucleos(t)ide analogue-focused library identified gemcitabine and its derivatives (compounds 1, 2a, and 3a) blocking influenza virus infection. To improve their antiviral selectivity by reducing cytotoxicity, 14 additional derivatives were synthesized in which the pyridine rings of 2a and 3a were chemically modified. Structure-and-activity and structure-and-toxicity relationship studies demonstrated that compounds 2e and 2h were most potent against influenza A and B viruses but minimally cytotoxic. It is noteworthy that in contrast to cytotoxic gemcitabine, they inhibited viral infection with 90% effective concentrations of 14.5-34.3 and 11.4-15.9 μM, respectively, maintaining viability of mock-infected cells over 90% at 300 μM. Resulting antiviral selectivity was comparable to that of a clinically approved nucleoside analogue, favipiravir. The cell-based viral polymerase assay proved the mode-of-action of 2e and 2h targeting viral RNA replication and/or transcription. In a murine influenza A virus-infection model, intraperitoneal administration of 2h not only reduced viral RNA level in the lungs but also alleviated infection-mediated pulmonary infiltrates. In addition, it inhibited replication of severe acute respiratory syndrome virus 2 infection in human lung cells at subtoxic concentrations. The present study could provide a medicinal chemistry framework for the synthesis of a new class of viral polymerase inhibitors.

Neonatal Exposure to Valproate Induces Long-Term Alterations in Steroid Hormone Levels in the Brain Cortex of Prepubertal Rats

Valproic acid (VPA) is a known drug for treating epilepsy and mood disorders; however, it is not recommended for pregnant women because of its possible teratogenicity. VPA affects neurotransmission and gene expression through epigenetic mechanisms by acting as a histone deacetylase inhibitor and has been used to establish animal models of autism spectrum disorder (ASD). However, studies on the long-term effects of early exposure to VPA on glucocorticoid and neurosteroid synthesis in the brain are lacking. Therefore, this study aimed to investigate the long-term changes in metabolic alterations and gene expression regulation according to sex, using metabolic steroid profiling data from cerebral cortex samples of rats four weeks after VPA exposure (400 mg/kg). In neonatal VPA-exposed models, estradiol levels decreased, and cytochrome P450 19A1 gene (Cyp19a1) expression was reduced in the prepubertal male cortex. Progesterone and allopregnanolone levels decreased, and 3β-hydroxysteroid dehydrogenase 1 gene (Hsd3b1) expression was also downregulated in the prepubertal female cortex. Furthermore, cortisol levels increased, and mRNA expression of the nuclear receptor subfamily 3 group C member 1 gene (Nr3c1) was downregulated in the cortices of both sexes. Unlike the neonatal VPA-exposed models, although a decrease in progestin and estradiol levels was observed in females and males, respectively, no differences were observed in cortisol levels in the cortex tissues of 8-week-old adult rats administered VPA for four weeks. These results indicate that early environmental chemical exposure induces long-term neurosteroid metabolic effects in the brain, with differences according to sex.

A Comparative Systematic Analysis of The Influence of Microplastics on Colon Cells, Mouse and Colon Organoids

BACKGROUND

Microplastics (MPs) are small fragments from any type of plastic formed from various sources, including plastic waste and microfibers from clothing. MPs degrades slowly, resulting in a high probability of human inhalation, ingestion and accumulation in bodies and tissues. As its impact on humans is a prolonged event, the evaluation of its toxicity and influence on human health are critical. In particular, MPs can enter the human digestive system through food and beverage consumption, and its effect on the human colon needs to be carefully examined.

METHODS

We monitored the influence of small MPs (50 and 100 nm) on human colon cells, human colon organoids and also examined their toxicity and changes in gene expression in vivo in a mouse model.

RESULTS

The data suggested that 5 mg/mL concentrations of 50 and 100 nm MPs induced a > 20% decrease in colon organoid viability and an increase in the expression of inflammatory-, apoptosis- and immunity-related genes. In addition, in vivo data suggested that 50 nm MPs accumulate in various mouse organs, including the colon, liver, pancreas and testicles after 7 d of exposure.

CONCLUSION

Taken together, our data suggest that smaller MPs can induce more toxic effects in the human colon and that human colon organoids have the potential to be used as a predictive tool for colon toxicity.

Biodegradable Block Copolymer-Tannic Acid Glue

Bioadhesives are becoming an essential and important ingredient in medical science. Despite numerous reports, developing adhesive materials that combine strong adhesion, biocompatibility, and biodegradation remains a challenging task. Here, we present a biocompatible yet biodegradable block copolymer-based waterborne superglue that leads to an application of follicle-free hair transplantation. Our design strategy bridges self-assembled, temperature-sensitive block copolymer nanostructures with tannic acid as a sticky and biodegradable polyphenolic compound. The formulation further uniquely offers step-by-step increases in adhesion strength via heating-cooling cycles. Combining the modular design with the thermal treating process enhances the mechanical properties up to 5 orders of magnitude compared to the homopolymer formulation. This study opens a new direction in bioadhesive formulation strategies utilizing block copolymer nanotechnology for systematic and synergistic control of the material's properties.