Search

The preparation of tetrakis(u-N, N'-diphenylbenzamidinato)dicobalt(II) (Co2 dbp 4) facilitated the direct analysis of the molecular, chemical and electronic structure of Co2(dbp)4 and dirhodium(dbp)4 (Rh2 dbp 4) compounds. The dicobalt complex was synthesized from the reaction of bis(4-cyclohexylbutyrato)cobalt(II) with lithium+(dbp)- in tetrahydrofuran solution. Moreover, the X-ray diffraction analysis shows that the molecular structure of both Co2(dbp)4 and Rh2(dbp)4 are basically similar.

Reports on the oxidation of aminodinitrotoluenes (ADNT) with ozone. Ratio of ozone-ADNT stoichiometries; Formation of glyoxylic and pyruvic acids; 1,3-dipolar cycloaddition of ozone to selected double bonds of the aromatic ring; Finding that the amino function is not involved in the initial ozone oxidation; Eventual incorporation into pyruvamide and oxamic acid.

Detections of internal substances and morphologies for label-free living cells are crucial for revealing malignant diseases. With the phase serving as a coupling of refractive index (RI) (marker for substances) and thickness (morphology), existing decoupling methods mainly rely on complex integrated systems or extensive optical field information. Developing simple and rapid decoupling methods remains a challenge. This study introduces a refractive index morphology imaging microscope (RIMIM) system utilizing polarization multiplexing for label-free single living cells. By simultaneous degree of circular polarization (DOCP) imaging and noninterferometric quantitative phase imaging (QPI), the intracellular refractive index distribution (IRID) and morphology can be decoupled. The optical thickness calculated from the phase is input into the circular depolarization decay model (CDDM) of degree of circular polarization to retrieve IRID. Subsequently, the thickness can be decoupled from phase result using retrieved IRID. Experiments conducted on mouse forestomach carcinoma (MFC) cells and human kidney-2 cells (HK-2) demonstrated the RIMIM system's ability to retrieve IRID and decouple fine morphology. Additionally, the RIMIM system effectively detected membrane damage and changes in erastin-induced ferroptotic HK-2 cells, with average and root-mean-square of surface folds 65.5% and 70.0% higher than those of normal HK-2 cells. Overall, the RIMIM system provides a simple and rapid method for decoupling RI and fine morphology, showing great potential for label-free live cells' cytopathology detection.

The excellent flexibility of silicone aerogels has attracted attention. However, the thermal conductivity of silicone aerogels is higher than that of inorganic silicone aerogels. Thermal conductivity can be reduced by increasing the thermal insulation of silicone aerogels while maintaining their flexibility. Herein, we successfully propose an ultrasimple strategy to prepare thermally conductive silicone aerogels using composite surfactants. Cetyltrimethylammonium chloride and cetyltrimethylammonium bromide were selected as complex surfactants with effective emulsification ability. The synthesized cationic/cationic surfactant emulsion aerogels exhibited high porosity (93%), flexibility, remarkable adiabatic properties (0.021 W m -1 K -1 thermal conductivity at 25 °C), thermal stability (68.71% thermogravimetric residue at 0-800 °C), and excellent flame-retardant capacity (vertical combustion test grade = V-0; limiting oxygen index = 27.30%), which made cationic/cationic surfactant emulsion aerogels a candidate material in the field of thermal insulation.

Chinese seedless breadfruit is rich in starch, lipids, and protein. To explore the interactions among these macromolecules during food processing, the seedless breadfruit starch-endogenous lipid-endogenous protein complex was investigated. Native seedless breadfruit starches are categorized as low-resistant-content starch [low-resistant starch (LRS)] or high-resistant starch (HRS). After complexation, dual self-assembly mechanisms occur after complexation. Initially, for the LRS group, long chains of amylopectin and amylose participate in complexation due to the migration from the short side chain of amylopectin, leading to an increase in RS content compared to the native starch. In contrast, amylose participated in complexation in the HRS group, which showed higher digestibility than that of raw starch. According to chemometric analysis, the HRS group complex possesses a more compact external and internal nanomicrostructure, leading to its weaker digestibility kinetics compared to the LRS group complex. This study provides a fundamental basis for the comprehensive application of novel multicomponent foods.

The primary challenge in microarray-based biological analysis lies in achieving the sensitive and specific detection of single-molecule targets while ensuring high reproducibility. A user-friendly digital imaging platform has been developed for the encoded trichromic profiling of circulating microRNAs (miRNAs). This platform replaces the traditional exponential polymerase amplification reaction (EXPAR) conducted on the microliter scale with a system that confines the amplification process within thousands of femtoliter-sized microdroplet reactors, cross-linked from tetra-armed poly(ethylene glycol) acrylate (Tetra-PEGA) and poly(ethylene glycol) dithiol (HS-PEG-SH), thus offering significant advantages, including minimal sample input, enhanced reactivity, and simplified analytical procedures. The quantitative analysis relies on digital counting of fluorescently positive microdroplets, each containing an individual miRNA sequence. This approach significantly reduces nonspecific amplification and improves sensitivity by over 2 orders of magnitude. The system has shown great potential in differentiating between subtypes of primary urethral carcinoma, suggesting its practical application in routine cancer diagnostics through simple urinalysis.

Metallic MXenes are promising two-dimensional materials for energy storage, (opto)electronics, and photonics due to their high electrical conductivity and strong light-matter interaction. Energy dissipation in MXenes is fundamental for photovoltaic and photothermal applications. Here we apply ultrafast laser spectroscopy across a broad time range (femto- to microseconds) to study the cooling dynamics of electrons and lattice in emerging Ti 2 CT x thin films compared to widely studied Ti 3 C 2 T x thin films. The carrier cooling time in Ti 2 CT x is persistently ∼2.6 ps without a hot-phonon bottleneck. After hot carrier cooling is completed, the transient absorption spectra of Ti 2 CT x MXene can be described well by the thermochromic effect. Heat dissipation in MXene thin films occurs over hundreds of nanoseconds with thermal diffusivities ∼0.06 mm 2 s -1 for Ti 2 CT x and ∼0.02 mm 2 s -1 for Ti 3 C 2 T x , likely due to inefficient interflake heat transfer. Our results unravel the energy dissipation dynamics in Ti 2 CT x films, showcasing potential applications in energy conversion.

Precise determination of the layer number ( N ) of hexagonal boron nitride (hBN) is crucial for its integration with other layered materials in applications such as ferroelectric devices and moiré potential modulation. We present a nondestructive method to accurately identify N , combining optical contrast analysis with second harmonic generation (SHG) measurements. By studying the flakes on 90 nm thick SiO 2 /Si substrates, we demonstrate that red-filtered optical images provide a clear contrast step in N with an uncertainty of ±1 layer, while SHG measurements further reduce the error by distinguishing even and odd layers. We also introduce a real-time detection technique to identify monolayer and few-layer hBN, improving flake identification efficiency. Given the growing interest in twisted hBN interfaces and their integration in van der Waals heterostructures, this method offers a practical approach for future studies.

Interfacial solar vapor generation is a promising technology for alleviating the current global water crisis, and the evaporation rate and efficiency have approached the theoretical limit. In a practical interfacial evaporation water purification system, the collection rate of purified water is typically lower than the evaporation rate. Passive collection devices based on gravity are susceptible to environmental influences and exhibit low collection efficiency, while active collection devices consuming external energy suffer from complex device systems and extra energy consumption. Given that both collection devices are nonselective and unable to distinguish contaminants mixed in the vapor, bionic membranes with autonomously passive and unidirectional water transfer capacity are developed through 3D printing for efficient water collection. More importantly, the bionic membranes are capable of high-speed water transportation without the need for external energy or gravity drive and liquid-selective transportation for separating oily pollutants from the collected products. The directional transport property facilitates the modular assembly of the bionic membrane, extending its application to practical large-scale solar-driven seawater desalination systems.

Each organelle referring to a complex multiorder architecture executes respective biological processes via its distinct spatial organization and internal microenvironment. As the assembly of biomolecules is the structural basis of living cells, creating synthetic nanoassemblies with specific physicochemical and morphological properties in living cells to interfere or couple with the natural organelle architectures has attracted great attention in precision therapeutics of cancers. In this review, we give an overview of the latest advances in the synthetic nanoassemblies for precise organelle regulation, including the formation mechanisms, triggering strategies, and biomedical applications in precision therapeutics. We summarize the emerging material systems, including polymers, peptides, and deoxyribonucleic acids (DNAs), and their respective intermolecular interactions for intercellular synthetic nanoassemblies, and highlight their design principles in constructing precursors that assemble into synthetic nanoassemblies targeting specific organelles in the complex cellular environment. We further showcase the developed intracellular synthetic nanoassemblies targeting specific organelles including mitochondria, the endoplasmic reticulum, lysosome, Golgi apparatus, and nucleus and describe their underlying mechanisms for organelle regulation and precision therapeutics for cancer. Last, the essential challenges in this field and prospects for future precision therapeutics of synthetic nanoassemblies are discussed. This review should facilitate the rational design of organelle-targeting synthetic nanoassemblies and the comprehensive recognition of organelles by materials and contribute to the deep understanding and application of the synthetic nanoassemblies for precision therapeutics.

How to fundamentally suppress charge transport is one of the essential issues in polymer dielectrics. This work reports significant charge transport suppression by glycidyl methacrylate (GMA) side group modification on polypropylene (PP). Experimental and computational investigations discover for the first time a quasi-hydrogen bond effect generated by carbonyl and epoxide of GMA in PP inter/intramolecular structure, while introducing trap energy levels within the HOMO-LUMO gap. These energy levels suppress the leakage current of GMA-modified PP thanks to the charge-trapping effect. The quasi-hydrogen bond originating from the interaction between the high-polar GMA group and flexible PP chain raises the thermostability while averaging the electron distribution between hydrogen and acceptor oxygen, which is conducive to lessening electric weak points, suppressing charge transport, and finally enhancing the electrical breakdown strength. This work provides new thinking on polymer dielectric design and charge transport regulation utilizing electron structure and weak interaction at the molecular scale.

The instability of the primary coal and rock structure significantly impacts the safety of coal mining and construction. The complex coal-rock interface cannot be simplified as a smooth surface. To investigate the dynamic response of primary composite coal and rock (primary-CCR), we studied the impact of load, hydrostatic pressure, and interface type on the mechanical behavior and macro/micro failure characteristics using a separate Hopkinson bar, a high-speed camera, and a scanning electron microscope. The results indicate a linear relationship between the composite strength, impact toughness, and impact velocity of the two types of composite coal and rock. The mechanical behavior of the primary-CCR initially increases and then decreases with the rise of hydrostatic pressure (turning point: 10 MPa). There is a positive correlation between artificial combined coal-rock (artificial-CCR) and hydrostatic pressure. The dissipative energy of combined coal and rock increases linearly with impact velocity. Initially, the dissipative energy per unit fracture area increases with hydrostatic pressure, then decreases as pressure continues to rise. Additionally, an increase in impact load causes the energy dissipation inflection point to shift forward. The primary interface significantly reduces the energy threshold for instability failure, resulting in a transition from energy transfer to energy dissipation in rock components. This transition manifests as the failure of artificial combined coal and rock cracks, which develop into rock fragments at an impact velocity of 14 m/s. Furthermore, the change in section roughness of coal and rock correlates with the degree of macroscopic crack growth, following the order: coal > primary-CCR > artificial-CCR > rock., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The exploration of structural interconversion in clusters triggered by external stimuli has attracted significant interest due to its potential to elucidate structure-property relationships of metal clusters. In this study, two types of silver clusters, Ag 2 and Ag 6 , are synthesized. Interestingly, the clusters exhibit reversible transformations in response to changes in the solvent conditions. The structures and optical properties of these clusters are thoroughly characterized using techniques such as mass spectrometry, single-crystal X-ray diffraction, photoluminescence, and radioluminescence spectroscopy. While both Ag 2 and Ag 6 display excellent photoluminescence properties, Ag 2 demonstrates superior performance in X-ray radioluminescence compared to Ag 6 . Flexible scintillator films fabricated from Ag 2 clusters exhibit outstanding X-ray imaging capabilities, achieving a spatial resolution of 15.0 lp/mm and an impressive detection limit for an X-ray dose of 0.58 μGy s -1 . This detection limit is nearly 10 times lower than the typical dose rate used in X-ray diagnostics (5.5 μGy s -1 ). This work introduces a novel approach for designing thiol-free silver clusters capable of solvent-dependent reversible interconversion, offering new insights into the development of silver clusters for advanced X-ray imaging applications.

Atomically precise Pd-thiolate clusters are well-known for their well-defined structures and diverse applications involving catalysis, sensors, and biomedicine. While many of these clusters have been studied, their molecular structures typically feature a tiara-like arrangement. In this study, we present the first example of a non-tiara-like Pd-thiolate cluster: the octahedral Pd 6 (SC 6 H 11 ) 12 (denoted as Pd 6 -Oct). The composition and geometric structure of the cluster were characterized using electrospray ionization mass spectrometry (ESI-MS) together with single-crystal X-ray diffraction (SXRD). Despite having a similar chemical composition to tiara-like Pd 6 (SC 2 H 4 Ph) 12 (denoted as Pd 6 -Tia), Pd 6 -Oct exhibits a distinctly different geometric structure. Additionally, UV-vis-NIR absorption spectroscopy combined with quantum chemical calculations provided valuable insights into the electronic structures of these clusters. The excited-state dynamics, host-guest chemistry, and the catalytic properties of Pd 6 -Oct and Pd 6 -Tia were examined to compare their structure-property relationships. This research represents significant advances in the synthesis and understanding of structure-property correlations in Pd-thiolate clusters.

Previous studies have demonstrated the remarkable properties of quad-rotor-shaped two-dimensional nonfullerene acceptors (2D NFAs), which encompass exceptional electron affinity, robust sunlight absorption, effective exciton separation, and accelerated electron transfer capabilities. Naphthalene has been demonstrated to be a significant 2D fused core to construct high-performance 2D NFAs. However, synthesizing such materials through existing synthetic pathways poses a significant challenge. In this work, we designed four 2D NFAs (TEA-SIC, TEA-SIC-8F, TEA-SIC-OH, and TEA-SIC-OH-8F) with an anthracene core. These NFAs can theoretically be synthesized into a quad-rotor configuration through a seven-step synthetic process. Theoretical calculations have demonstrated that these 2D NFAs exhibit superior electron-accepting abilities, enhanced sunlight absorption, and more efficient exciton dissociation compared to Y6. Furthermore, TEA-SIC and TEA-SIC-8F exhibited impressive electron mobilities of 1.76 × 10 -3 cm 2 V -1 s -1 and 1.18 × 10 -3 cm 2 V -1 s -1 , respectively, indicating their suitability for the development of high-performance organic solar cells (OSCs). Although TEA-SIC-OH and TEA-SIC-OH-8F have lower electron mobility, their high sunlight absorption and efficient exciton separation suggest potential as third components in ternary OSCs. These 2D NFAs also exhibit a commendable solubility in most alcohol-based solvents, indicating their potential for specialized applications in the fabrication of stacked OSCs. These findings provide valuable insights for the future design of synthesizable high-performance 2D NFAs.

High-/medium-entropy materials have been explored as promising electrocatalysts for water splitting due to their unique physical and chemical properties. Unfortunately, state-of-the-art materials face the dilemma of explaining the enhancement mechanism, which is now limited to theoretical models or an unclear cocktail effect. Herein, a medium-entropy NiCoFeMnP with an advanced hierarchical particle-nanosheet-tumbleweed nanostructure has been synthesized via simple precursor preparation and subsequent phosphorization. Evaluated as the electrocatalyst for oxygen evolution reaction (OER), the medium-entropy NiCoFeMnP displays a lower overpotential of 272 mV at a current density of 10 mA cm -2 , and more favorable kinetics than the binary NiFeP, ternary NiCoFeP, quaternary NiCoFeCuP and NiCoFeCrP counterparts, and other reported high-/medium-entropy electrocatalysts. Careful experimental analyses reveal that the incorporation of Mn can significantly regulate the electronic structure of Ni, Co, and Fe sites. More importantly, the Mn introduction and entropy stabilization effect in the reconstructed metal (oxy)hydroxide simultaneously promote the lattice oxygen mechanism, improving the activity. This work sheds new light on the design of high-/medium-entropy materials from an in-depth understanding of the underlying mechanism for improving energy conversion efficiency.

ConspectusIn recent years, the controlled assembly/disassembly of exogenous chemical components inside cells has become an emerging approach to regulating cell functions. However, the construction of dynamic material chemistry systems in living cells always remains highly challenging due to the complicated intracellular microenvironment. Nucleic acid is a category of biological components that can achieve efficient molecular assembly via specific base-pairing and perform biological functions in the intracellular microenvironment. Deoxyribonucleic acid (DNA) molecules exhibit the superior performance of intracellular assembly, including sequence programmability, molecule recognition ability, and nanostructure predictability, as well as the unique biological functions that traditional synthetic polymers do not carry, showing great superiority in the construction of dynamic material chemistry systems. Moreover, the technologies of DNA synthesis are relatively mature, and the conjugation of DNA with functional small molecules can be achieved through established chemical synthesis methods, facilitating the construction of DNA-based dynamic materials with more functions. In addition, a few specific DNA molecules have been proven to show responsiveness toward different stimuli, functioning as dynamic modules.In this Account, we summarize our recent work in dynamic chemistry of DNA-based nanoassemblies in living cells from the perspective of stimulus types including enzyme, H + , glutathione (GSH), adenosine triphosphate (ATP), and light. Upon the specific stimuli, DNA-based nanoassemblies undergo precise assembly in living cells, executing disassembly or aggregation, which consequently affects the functions and behaviors of living cells. In the first part, we describe the interactions between DNA-based nanoassemblies and intracellular enzymes, namely the enzymatic cleavage of intracellular enzymes on the DNA or RNA sequences. In the second part, we summarize the effects of H + in lysosomes on DNA-based nanoassemblies, including the formation of a tetraplex i-motif structure and the decomposition of acid-degradable polymeric coating. In the third part, we discuss the mechanism of GSH responsiveness of DNA-based nanoassemblies, including the breaking of disulfide bonds and reduction-responsive nanoparticles. In the fourth part, we describe the ATP-mediated conformational transition for the specific release of functional RNA sequences. In the fifth part, we demonstrate the light-mediated spatiotemporally dynamic chemistry of DNA-based nanoassemblies. In summary, based on the achievements of our group in the study of dynamic chemistry of DNA-based nanoassemblies, the assembly, disassembly, and reassembly in living cells are well-controlled, the regulation of cellular functions are explored, and the new strategies for cancer therapeutics are demonstrated. We envision that our work on the dynamic chemistry of DNA-based nanoassembly is a new paradigm for constructing dynamic material chemistry systems inside living cells, and will facilitate the development of precision medicine.

Single metal atom catalysts (SACs) have garnered considerable attention as promising agents for catalyzing important industrial reactions, particularly the electrochemical synthesis of hydrogen peroxide (H 2 O 2 ) through the two-electron oxygen reduction reaction (ORR). Within this field, the metal atom-support interaction (MASI) assumes a decisive role, profoundly influencing the catalytic activity and selectivity exhibited by SACs, and triggers a decade-long surge dedicated to unraveling the modulation of MASI as a means to enhance the catalytic performance of SACs. In this comprehensive review, we present a systematic summary and categorization of recent advancements pertaining to MASI modulation for achieving efficient electrochemical H 2 O 2 synthesis. We start by introducing the fundamental concept of the MASI, followed by a detailed and comprehensive analysis of the correlation between the MASI and catalytic performance. We describe how this knowledge can be harnessed to design SACs with optimized MASI to increase the efficiency of H 2 O 2 electrosynthesis. Finally, we distill the challenges that lay ahead in this field and provide a forward-looking perspective on the future research directions that can be pursued.

Recent years have seen the rapid development of miniaturized reconstructive spectrometers (RSs), yet they still confront a range of technical challenges, such as bandwidth/resolution ratio, sensing speed, and/or power efficiency. Reported RS designs often suffer from insufficient decorrelation between sampling channels, which, in essence, is due to inadequate engineering of sampling responses. This in turn results in poor spectral-pixel-to-channel ratios (SPCRs), typically restricted at single digits. So far, there lacks a general guideline for manipulating RS sampling responses for the effectiveness of spectral information acquisition. In this study, we shed light on a fundamental parameter from the compressive sensing (CS) theory-the average mutual correlation coefficient ν -and provide insight into how it serves as a critical benchmark in RS design. To this end, we propose a novel RS design with multiresonant cavities, consisting of a series of partial reflective interfaces. Such multicavity configuration allows the superlative optimization of sampling matrices to achieve minimized ν . Experimentally, we implement a single-shot, dual-band RS on a SiN platform, realizing an overall operation bandwidth of 270 nm and a <0.5 nm resolution with only 15 sampling channels per band. This leads to a record high SPCR of 18.0. Moreover, the proposed multicavity design can be readily adapted to various photonic platforms, ranging from optical fibers to free-space optics. For instance, we showcase that by employing multilayer coatings, an ultrabroadband RS can be optimized to exhibit a 700 nm bandwidth with an SPCR of over 100., Competing Interests: The authors declare the following competing financial interest(s): GlitterinTech Limited declares a published patent (Patent num-ber: ZL202310810481.1) which relates to the spectrometer design presented in this work. This patent was also pursued as a pending PCT application (application number: PCT/CN2023/115897). The authors declare no other competing interests., (© 2024 The Authors. Published by American Chemical Society.)

Quantum dot (QD) solids are emerging materials for many optoelectronic applications. To enhance interdot coupling and charge transport, surface ligands can be removed, allowing individual QDs to be attached along specific crystal orientations (termed "oriented attachment"). Optimizing the electronic and optical properties of QD solids demands a comprehensive understanding of the nanoscale energy flow in individual and attached QDs under photoexcitation. In this work, we employed ultrafast electron diffraction to directly measure how oriented attachment along ⟨100⟩ directions affects the nonequilibrium lattice dynamics of lead selenide QDs. The oriented attachment anisotropically alters the ultrafast energy relaxation along specific crystal axes. Along the ⟨100⟩ directions, both the lattice deformation and atomistic random motions are suppressed in comparison with those of individual QDs. Conversely, the effects are enhanced along the unattached ⟨111⟩ directions due to ligand removal. The oriented attachment switches the major lattice thermalization pathways from ⟨100⟩ to ⟨111⟩ directions.

In perovskite solar cells (PSCs), the electron transfer layer (ETL) characteristics have significant effects on the photoelectric conversion efficiency (PCE) of the devices. Herein, a natural chelating agent polymer polyaspartic acid (PASP) is doped into the SnO 2 precursor solution attributed to a strong interaction between PASP molecules and SnO 2 , which strengthens the interface contact and passivates the vacancy oxygen trap of the obtained SnO 2 ETL, thus promoting the transfer of electrons. In addition, PASP can also regulate the growth of perovskite crystals, leading to an improved crystal quality of the perovskite films. Meanwhile, there is an excellent chelate anchoring of PASP to uncoordinated Pb 2+ , facilitating the reduction of trap defects at the interface, improving the stability of device, and suppressing the leakage of toxic Pb. Finally, the photovoltaic performance of the optimized device was greatly improved, and the PCE was increased from 21.22 to 23.49%, with outstanding environmental stability. This work provides an inexpensive and efficient treatment strategy that improves the performance and stability of friendly environmental PSCs.

The pH and humidity of the crop environment are essential indicators for monitoring crop growth status. This study reports a lead-free perovskite/polyvinylidene fluoride-hexafluoropropylene composite (LPPC) to enhance the stability and reliability of in situ plant pH and humidity monitoring. The mesh composite membrane of LPPC illustrates a hydrophobic contact angle of 101.982°, a tensile strain of 800%, and an opposing surface potential of less than -184.9 mV, which ensures fast response, high sensitivity, and stability of the sensor during long-term plant monitoring. The LPPC-coated pH electrode possesses a sensitivity of -63.90 mV/pH, which provides a fast response within 5 s and is inert to environmental temperature interference. The LPPC-coated humidity sensor obtains a sensitivity of -145.7 Ω/% RH, responds in 28 s, and works well under varying light conditions. The flexible multimodal sensor coated with an LPPC membrane completed real-time in situ monitoring of soilless strawberries for 17 consecutive days. Satisfactory consistency and accuracy performance are observed. The study provides a simple solution for developing reliable, flexible wearable multiparameter sensors for in situ monitoring of multiple parameters of crop environments.

Nanocrystalline Au-Co 3 O 4 thin films were fabricated through a facile solution-processing method, and voltage-polarity-dependent resistive switching (RS) characteristics including variability of Set/Reset voltages, stability of cycling endurance, and carriers transport mechanism were studied in the Pt/Au-Co 3 O 4 /Pt memory devices. The switching voltages of the Set and Reset processes in the bipolar RS memristors exhibited lower variability as compared to the unipolar resistance switching devices. Moreover, the switching performance of cycle-to-cycle endurance in bipolar mode had a smaller fluctuation than those of unipolar switching behavior. Based on the current-voltage curve fitting analysis, it was found that Ohmic-conduction behaviors dominated the carriers transport of low-resistance state regardless of unipolar or bipolar switching behaviors. The carrier transport of high resistance state was governed following Poole-Frenkel emission and Schottky emission mechanisms in the unipolar and bipolar switching modes, respectively. The physical switching mechanism of Pt/Au-Co 3 O 4 /Pt memory devices was proposed using the model by means of growth and disruption of conducting filaments, involved in memory effects of thermochemical mechanism and valence change mechanism in the unipolar and bipolar RS, respectively. The proposed model following the finite element method revealed the roles of electrical field distribution and temperature gradient to further clarify the RS mechanism. Our results open a door for understanding and optimizing oxide-based thin-film resistance switching memory devices., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Chiral coumarins and their derivatives are prominent bioactive structural units present in a wide range of natural products and pharmaceutical candidates. Therefore, the development of straightforward and efficient methodologies for the synthesis of readily functionalized chiral coumarins is of significant interest. Herein we report an enantioselective copper-catalyzed yne-allylic substitution of coumarins, resulting in a highly regioselective synthesis of diverse new classes of chiral coumarin derivatives with high efficiency and excellent functional group tolerance. Subsequent versatile transformations further demonstrate the substantial synthetic potential of this strategy in the field of biochemical research.

The abuse or misuse of antibiotics in clinical and agricultural settings severely endangers human health and ecosystems, which has raised profound concerns for public health worldwide. Trace detection and reliable discrimination of commonly used fluoroquinolone (FQ) antibiotics and their analogues have consequently become urgent to guide the rational use of antibiotic medicines and deliver efficient treatments for associated diseases. Herein, we report a wearable eye patch integrated with a quadruplex nanosensor chip for noninvasive detection and discrimination of primary FQ antibiotics in tears during routine eyedrop treatment. A set of dual-mode fluorescent nanoprobes of red- or green-emitting CdTe quantum dots integrated with lanthanide ions and a sensitizer, adenosine monophosphate, were constructed to provide an enhanced fluorescence up to 45-fold and nanomolar sensitivity toward major FQs owing to the aggregation-regulated antenna effect. The aggregation-driven, CdTe-Ln(III)-based microfluidic sensor chip is highly specific to FQ antibiotics against other non-FQ counterparts or biomolecular interfering species and is able to accurately discriminate nine types of FQ or non-FQ eyedrop suspensions using linear discriminant analysis. The prototyped wearable sensing detector has proven to be biocompatible and nontoxic to human tissues, which integrates the entire optical imaging modules into a miniaturized, smartphone-based platform for field use and reduces the overall assay time to ∼5 min. The practicability of the wearable eye patch was demonstrated through accurate quantification of antibiotics in a bactericidal event and the continuous profiling of FQ residues in tears after using a typical prescription antibiotic eyedrop. This technology provides a useful supplement to the toolbox for on-site and real-time examination and regulation of inappropriate daily drug use that might potentially lead to long-term antibiotic abuse and has great implications in advancing personal healthcare techniques for the regulation of daily medication therapy.

The advent of catheter-based minimally invasive surgical instruments has provided an effective means of diagnosing and treating human disease. However, conventional medical catheter devices are limited in functionalities, hindering their ability to gather tissue information or perform precise treatment during surgery. Recently, electronic catheters have integrated various sensing and therapeutic technologies through micro/nanoelectronics, expanding their capabilities. As micro/nanoelectronic devices become more miniaturized, flexible, and stable, electronic surgical catheters are evolving from simple tools to multiplexed sensing and theranostics for surgical applications. The review on multifunctional electronic surgical catheters is lacking and thus is not conducive to the reader's comprehensive understanding of the development trend in this field. This review covers the advances in multifunctional electronic catheters for precise and intelligent diagnosis and therapy in minimally invasive surgery. It starts with the summary of clinical minimally invasive surgical instruments, followed by the background of current clinical catheter devices for sensing and therapeutic applications. Next, intelligent electronic catheters with integrated electronic components are reviewed in terms of electronic catheters for diagnosis, therapy, and multifunctional applications. It highlights the present status and development potential of catheter-based minimally invasive surgical devices, while also illustrating several significant challenges that remain to be overcome.

Layer-engineered interlayer excitons from heterostructures of transition-metal dichalcogenides (TMDCs) exhibit a rich variety of emissive states and intriguing valley spin-selection rules, the effective modulation of which is crucial for excitonic physics and related device applications. Strain or high pressure provides the possibility to tune the energy of the interlayer excitons; however, the reported emission intensity is substantially quenched, which greatly limits their practical application in optoelectronic devices. Here, via applying uniaxial strain based on polyvinyl alcohol (PVA) encapsulation technique, we report enhanced layer-engineered interlayer exciton emission intensity with largely modulated emission energy in WSe 2 /WS 2 heterobilayer and heterotrilayer. Both momentum-direct and momentum-indirect interlayer excitons were observed, and their emission energies show an opposite shift tendency upon applied strain, which agrees with our DFT calculations. We further demonstrate that intralayer and interlayer exciton states with low phonon interactions can be modulated through the mechanical strain applied to the PVA substrate at low temperatures. Due to strain-induced breaking of the 3-fold rotational symmetry, we observe the enhanced valley polarization of interlayer excitons. Our study contributes to the understanding and modulation of the optical properties of interlayer excitons, which could be exploited for optoelectronic device applications.

5,10-Dimethyl-5,10-dihydrophenazine ( MP ) is utilized as an effective auxochrome, leveraging its highly conjugated structure to enhance the photophysical and photochemical properties of fluorophores. As illustrated in the difluoride-boron complex and coumarin fluorophores, the extensive conjugation of MP auxochrome substantially red-shifts the absorption/emission wavelengths and increases Stokes shift due to the intensified intramolecular charge transfer effect; notably, MP auxochrome effectively improves fluorophores' photostability by mitigating photooxidative reactions through enhanced electron density delocalization on nitrogen atoms and increased ionization potential. Importantly, MP-based fluorophores demonstrate applicability in stimulated emission depletion nanomicroscopy, showcasing their utility in lipid droplet labeling.

Herein, an efficient ( t BuO) 2 Mg promoted [3 + 2] annulation of δ-acetoxy allenoates with N -benzylhydroxylamine has been developed. This method provides a concise and facile protocol to synthesize vinylated isoxazol-5(2 H )-one derivatives stereospecifically in a broad substrate scope with high efficiency (31 examples, up to 87% yield).

Tumor microenvironment-responsive phototheranostic agents are highly sought after for their ability to improve diagnostic accuracy and treatment specificity. Here, we introduce a novel single-molecule probe, POZ-NO , which is activated by nitric oxide (NO) and weak acidity, enabling dual-mode imaging and photothermal therapy (PTT) of tumors. In acidic environments with elevated NO levels, POZ-NO exhibits a distinctive ratiometric fluorescence signal shift from the red to near-infrared, accompanied by a 700 nm photoacoustic signal. Additionally, POZ-NO demonstrated potent photothermal effects upon NO and acidity activation, achieving an impressive conversion efficiency of 74.3% under 735 nm laser irradiation. In vivo studies confirm POZ-NO 's ability to accurately image tumors through ratiometric fluorescence and photoacoustic modes while selectively treating tumors with PTT.

The authentication of ingredients in formulas is crucial yet challenging, particularly for constituents with comparable compositions but vastly divergent efficacy. Rehmanniae Radix and its derivatives are extensively utilized in food supplements, which contain analogous compositions but very distinct effects. Rehmanniae Radix, also a difficult-to-detect herbal ingredient, was chosen as a case to explore a novel HPTLC-QDa MS technique for the identification of herbal ingredients in commercial products. Through systematic condition optimization, including thin layer and mass spectrometry, a stable and reproducible HPTLC-QDa MS method was established, which can simultaneously detect oligosaccharides and iridoids. Rehmannia Radix and its processed products were then analyzed to screen five markers that could distinguish between raw and prepared Rehmannia Radix. An HPTLC-QDa-SIM method was further established for formula detection by using the five markers and validated using homemade prescriptions and negative controls. Finally, this method was applied to detect raw and prepared Rehmannia Radix in 12 commercial functional products and supplements.

Cocrystal screening and single-crystal growth remain the primary obstacles in the development of pharmaceutical cocrystals. Here, we present a new approach for cocrystal screening, microspacing in-air sublimation (MAS), to obtain new cocrystals and grow high-quality single crystals of cocrystals within tens of minutes. The method possesses the advantages of strong designable ability of devices, user-friendly control, and compatibility with materials, especially for the thermolabile molecules. A novel drug-drug cocrystal of favipiravir (FPV) with salicylamide (SAA) was first discovered by this method, which shows improved physiochemical properties. Furthermore, this method proved effective in cultivating single crystals of FPV-isonicotinamide (FPV-INIA), FPV-urea, FPV-nicotinamide (FPV-NIA), and FPV-tromethamine (FPV-Tro) cocrystals, and the structures of these cocrystals were determined for the first time. By adjusting the growth temperature and growth distance precisely, we also achieved single crystals of 10 different paracetamol (PCA) cocrystals and piracetam (PIR) cocrystals, which underscores the versatility and efficiency of this method in pharmaceutical cocrystal screening.

Room-temperature photoactivation of the first- and second-generation PN 3 P-pincer nickel azido complexes 1a and 1b in the presence of CO 2 or CS 2 afforded N-bound carbamates, dithiocarbamates, and isothiocyanates, providing insights into CO 2 and CS 2 activation and demonstrating how a seemingly small difference in the ligand structure significantly influences the reactivity. Theoretical calculations disclosed that the charge of the phosphorus atom plays a critical role in determining the nitrogen atom transfer to form a plausible nickel phosphiniminato intermediate.

1,2-Bis(diphenylphosphino)ethanes (DPPEs) are versatile and immensely important ligands in transition metal catalysts. Here we report the dithiophosphinylation of readily available allenyl acetates to give DPPEs in high yields and regioselectivity. This protocol features a broad substrate scope and mild conditions, avoiding the use of transition metals and air-sensitive sources of phosphorus. Mechanism studies indicate that the reaction was accomplished via an S N 2'-type addition-elimination followed by a 1,4-addition step.

A selective tumor-penetrating strategy generally exploits tumor-targeted ligands to modify drugs so that the conjugate preferentially enters tumors and subsequently undergoes transcellular transport to penetrate tumors. However, this process shields ligands from their corresponding targets on the cell surface, possibly inducing an off-target effect during drug penetration at the tumor-normal interface. Herein, we first describe a selective tumor-penetrating drug (R11-phalloidin conjugates) for intravesical therapy of bladder cancer. The intravesical conjugates rapidly translocated across the mucus layer, specifically bound to tumors, and infiltrated throughout the tumor via direct intercellular transfer. Notably, direct transfer from normal cells to tumor cells was unidirectional because the pathways required for direct transfer, termed F-actin-rich tunneling nanotubes, were more unidirectionally extended from normal cells to tumor cells. Moreover, the intravesical conjugates displayed strong anticancer activity and well-tolerated biosafety in murine orthotopic bladder tumor models. Our study demonstrated the potential of a selective tumor-penetrating conjugate for effective intravesical anticancer therapy.

Managing diabetes is a chronic challenge today, requiring monitoring and timely insulin injections to maintain stable blood glucose levels. Traditional clinical testing relies on fingertip or venous blood collection, which has facilitated the emergence of continuous glucose monitoring (CGM) technology to address data limitations. Continuous glucose monitoring technology is recognized for tracking long-term blood glucose fluctuations, and its development, particularly in wearable devices, has given rise to compact and portable continuous glucose monitoring devices, which facilitates the measurement of blood glucose and adjustment of medication. This review introduces the development of wearable CGM-based technologies, including noninvasive methods using body fluids and invasive methods using implantable electrodes. The advantages and disadvantages of these approaches are discussed as well as the use of microneedle arrays in minimally invasive CGM. Microneedle arrays allow for painless transdermal puncture and are expected to facilitate the development of wearable CGM devices. Finally, we discuss the challenges and opportunities and look forward to the biomedical applications and future directions of wearable CGM-based technologies in biological research.

Developing dynamic nanostructures for in situ regulation of biological processes inside living cells is of great importance in biomedical research. Herein we report the cascaded assembly of Y-shaped branched DNA nanostructure (YDN) during intracellular autophagy. YDN contains one arm with semi-i-motif sequence and Cy3-BHQ2, and another arm with an apurinic/apyrimidinic (AP) site and Cy5-BHQ3. Upon uptake by cancer cells, intermolecular i-motif structures are formed in response to lysosomal H + , causing the formation of YDN-dimer and the recovery of Cy3 fluorescence; when escapes occur from the lysosome to the cytoplasm, the YDN-dimer responds to the overexpressed APE1, leading to the assembly of YDN into the DNA network and the fluorescence recovery of Cy5. Simultaneously, the cascaded assembly activates autophagy, and thus the process of assembly of YDN and autophagy flux can be spatiotemporally coupled. This work illustrates the potential of DNA nanostructures for the in situ regulation of intracellular dynamic events with spatiotemporal control.

In situ conversion technology is a green and effective way to realize the development of organic-rich shale. Supercritical CO 2 can be used as a good heating medium for shale in situ conversion. Numerical simulation is an important means to explore the shale in situ conversion process, but it requires a lot of time and computational cost for in situ conversion simulation under different working conditions. Therefore, a computational framework for rapid prediction of shale in situ conversion development performance and heating parameter optimization is proposed by coupling artificial neural network (ANN) and particle swarm optimization (PSO). The results indicated that kerogen pyrolysis and hydrocarbon product release mainly occurred within 2 years of shale in situ conversion. The production curves of pyrolysis hydrocarbon obviously slowed after in situ conversion for 2 years. The database was constructed by a large number of in situ conversion simulations, and Pearson correlation analysis and the random forest method were adopted to obtain seven main controlling factors affecting reservoir temperature and hydrocarbon production. The determination coefficient of the obtained ANN-based prediction models is higher than 97%, and the mean square error (MSE) is lower than 0.3%. The basic reservoir case can choose to inject 350-450 °C supercritical CO 2 (Sc-CO 2 ) fluid with a rate of 600 m 3 /day to obtain a more promising development effect. The heating parameter optimization for three typical reservoir cases using PSO was performed, and reasonable injection temperature and injection rate were obtained. It realized accurate development prediction and rapid heating parameter optimization, which helps the effective application of shale in situ conversion development design., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Flexible sensors for application in various industries, including biomedicine and wearable electronics, are frequently made using silver nanoparticle (AgNP) inks and inkjet printing (IJP) technology. Inkjet-printed flexible electronic devices are made up of many printed lines that run parallel to each other, and the surface morphology of the printed lines and the interline state directly impact the electrical conductivity of the electronic devices. This paper describes the experimental setup for IJP, the definition of print line characteristics, and common unavoidable defects. Conductivity and physical defects are considered in defining the print line quality assessment. In addition, two prediction models of flexible sensors before batch printing and a model for detecting defects after printing are provided. The predictive models can guide actions, leading to a print success rate of over 80%. We build the defect detection model using a neural architecture search because manually fine-tuning neural networks for reference is challenging. Finally, a target detection model with a mAP@0.5 of 81.2% is built in just 0.77 graphics processing unit (GPU) days. The model takes only 4.6 ms to detect an image, satisfying the real-time monitoring needs. At the same time, an accuracy of 95.5% can be achieved in the test data set. This work provides a new idea for the high-volume preparation of flexible sensors.

N-heterocyclic carbenes (NHCs) have been extensively studied to modulate the reactivity of molecular catalysts, colloids, and their supported analogues, being isolated sites, clusters, or nanoparticles. While the interaction of NHCs on metal surfaces has been discussed in great detail, showing specific coordination chemistry depending on the type of NHC ligands, much less is known when the metal is dispersed on oxide supports, as in heterogeneous catalysts. Herein, we study the interaction of NHC ligands with Au surface sites dispersed on silica, a nonreducible oxide support. We identify the easy formation of bis-NHC ligated Au(I) surface sites parallel to what is found on metallic Au surfaces. These species display a specific 13 C NMR spectroscopic signature that clearly distinguishes them from the mono-NHC Au(I) surface sites or supported imidazoliums. We find that bis-ligated surface species are not unique to supported Au(I) species and are found for the corresponding Ag(I) and Cu(I) species, as well as for the isolobal surface silanols. Furthermore, the interaction of NHC ligand with silica-supported Au nanoparticles also yields bis-NHC ligated Au(I) surface sites, indicating that metal atoms can also be easily extracted from nanoparticles, further illustrating the dynamics of these systems and the overall favorable formation of such bis-ligated species across a range of systems, besides what has been found on crystalline metal facets.

Nucleases present a formidable barrier to the application of nucleic acids in biology, significantly reducing the lifetime of nucleic acid-based drugs. Here, we develop a novel methodology to protect DNA and RNA from nucleases by reconfiguring their supramolecular structure through the addition of a nucleobase mimic, cyanuric acid. In the presence of cyanuric acid, polyadenine strands assemble into triple helical fibers known as the polyA/CA motif. We report that this motif is exceptionally resistant to nucleases, with the constituent strands surviving for up to 1 month in the presence of serum. The conferred stability extends to adjacent non-polyA sequences, albeit with diminishing returns relative to their polyA sections due to hypothesized steric clashes. We introduce a strategy to regenerate stability through the introduction of free polyA strands or positively charged amino side chains, enhancing the stability of sequences of varied lengths. The proposed protection mechanism involves enzyme failure to recognize the unnatural polyA/CA motif, coupled with the motif's propensity to form long, bundling supramolecular fibers. The methodology provides a fundamentally new mechanism to protect nucleic acids from degradation using a supramolecular approach and increases lifetime in serum to days, weeks, or months.

The usage of a conductive hydrogel in wearable sensors has been thoroughly researched recently. Nonetheless, hydrogel-based sensors cannot simultaneously have excellent mechanical property, high sensitivity, comfortable wearability, and rapid self-healing performance, which result in poor durability and reusability. Herein, a robust conductive hydrogel derived from one-pot polymerization and subsequent solvent replacement is developed as a wearable sensor. Owing to the reversible hydrogen bonds cross-linked between polymer chains and clay nanosheets, the resulting conductive hydrogel-based sensor exhibits outstanding flexibility, self-repairing, and fatigue resistance performances. The embedding of graphene oxide nanosheets offers an enhanced hydrogel network and easy release of wearable sensor from the target position through remote irradiation, while Li + ions incorporated by solvent replacement endow the wearable sensor with low detection limit (sensing strain: 1%), high conductivity (4.3 S m -1 ) and sensitivity (gauge factor: 3.04), good freezing resistance, and water retention. Therefore, the fabricated wearable sensor is suitable to monitor small and large human motions on the site and remotely under subzero (-54 °C) or room temperature, indicating lots of promising applications in human-motion monitoring, information encryption and identification, and electronic skins.

A monolithic catalyst was fabricated through an emulsion-templating method, postpolymerization modification, and in situ loading of active constituents. To achieve a high specific surface area, divinylbenzene (DVB) was solely employed as the monomer, while the porous structure was adjusted with the porogen content and the types of initiators. Then, anchor points were introduced on the pore wall through nitration and amination of the polymeric scaffold. Using a controlled "silver mirror reaction", monolithic catalysts were obtained after loading of silver nanoparticles (Ag NPs), which was verified from morphological and crystallinity characteristics. The catalytic performance of the resultant monolithic catalyst was determined with the model reduction of 4-nitrophenol (4-NP). In static catalysis, the monolithic catalyst was proved to have a reactively high apparent rate constant and a good reusability. Furthermore, a flow reactor was fabricated with the monolithic catalyst, showing a high efficiency and long-term durability for the continuous reduction of 4-NP. This work broadened the adjustment of porous structures and the subsequent application for emulsion-templated monoliths.

Over the past decade, superhydrophilic zwitterionic surfaces, slippery liquid-infused porous surfaces, covalently attached liquid-like surfaces, and superhydrophobic surfaces have emerged as the most promising strategies to prevent biofouling on biomedical devices. Despite working through different mechanisms, they have demonstrated superior efficacy in preventing the adhesion of biomolecules (e.g., proteins and bacteria) compared with conventional material surfaces. However, their potential in combating catheter-associated urinary tract infection (CAUTI) remains uncertain. In this research, we present the fabrication of these four coatings for urinary catheters and conduct a comparative assessment of their antifouling properties through a stepwise approach. Notably, the superhydrophilic zwitterionic coating demonstrated the highest antifouling activity, reducing 72.3% of fibrinogen deposition and over 75% of bacterial adhesion ( Escherichia coli and Staphylococcus aureus ) when compared with an uncoated polyvinyl chloride (PVC) surface. The zwitterionic coating also exhibited robust repellence against blood and improved surface lubricity, decreasing the dynamic coefficient of friction from 0.63 to 0.35 as compared with the PVC surface. Despite the fact that the superhydrophilic zwitterionic and hydrophobic liquid-like surfaces showed great promise in retarding crystalline biofilm formation in the presence of Proteus mirabilis , it is worth noting that their long-term antifouling efficacy may be compromised by the proliferation and migration of colonized bacteria as they are unable to kill them or inhibit their swarming. These findings underscore both the potential and limitations of these ultralow fouling materials as urinary catheter coatings for preventing CAUTI.

Electron delocalization has an important impact on the physical properties of condensed materials. However, the L-electron delocalization in inorganic, especially nitrogen, compounds needs exploitation to improve the energy efficiency, safety, and environmental sustainability of high-energy-density materials (HEDMs). This Letter presents an intriguing N 8 molecule, ingeniously utilizing nitrogen's L-electron delocalization. The molecule, exhibiting a unique lollipop-shaped conformation, can fold at various angles with very low energy barriers, self-assembling into environmentally stable, all-nitrogen crystals. These crystals demonstrate unparalleled stability, high energy density, low mechanical sensitivity, and optimal electronic thermal conductivity, outperforming existing HEDMs. The remarkable properties of these designed materials are attributed to two distinct delocalized systems within nitrogen's L-shell: π- and lone pair σ-electrons, which not only stabilize the molecular structure but also facilitate interconnected 3D networks of intermolecular nonbonding interactions. This work might pave the way to the experimental synthesis of environmentally stable all-nitrogen solids.

Ginsenoside Rg1 (Rg1) is the main bioactive ginseng component. This study investigates the effects of Rg1 on cognitive deficits triggered by chronic sleep deprivation stress (CSDS) and explores its underlying mechanisms. Rg1 effectively improved spatial working and recognition memory, as evidenced by various behavioral tests. RNA-sequence analysis revealed differential gene expression in the metabolic pathway. Treatment with Rg1 abrogated reductions in SOD and CAT activity, lowered MDA content, and increased Nrf2 and HO-1 protein levels. Rg1 administration alleviated hippocampal mitochondrial dysfunction by restoring normal ultrastructure and enhancing ATP activities and Mfn2 expression while regulating Drp-1 expression. Rg1 mitigated neuronal apoptosis by reducing the Bax/Bcl-2 ratio and the levels of cleaved caspase-3. Additionally, Rg1 upregulated AMPK and SIRT3 protein expressions. These findings suggest that Rg1 has potential as a robust intervention for cognitive dysfunction associated with sleep deprivation, acting through the modulation of mitochondrial function, oxidative stress, apoptosis, and the AMPK-SIRT3 axis.