Browse Articles

Phase reconstruction and causality in nano-FTIR signals based on the finite dipole model with Kramers–Kronig relations

Leveraging the Enantiomeric Excess of Catalyst for Precise Stereocontrol in Poly(3‐hydroxybutyrate)

ABSTRACT The properties of polymers are governed by multi‐level structural parameters, with tacticity being particularly critical for crystallization, thermal, and mechanical performance. Conventional approaches to modulate tacticity—such as tuning monomer enantiomeric excess or synthesizing distinct catalysts—are often complex and lack precise control. To address this challenge, we present a stereocontrol strategy by exploiting an enantiopure catalyst governed by an enantiomorphic site control (ESC) mechanism and polymeric exchange between the enantiomer pair. As a result, the enantiopure DiMeBiPh‐BINOL‐salen catalysts ( R , R )‐ Y1 and ( S , S )‐ Y1 were designed and demonstrated outstanding isoselectivity for the ROP of rac ‐BBL via the ESC mechanism. Their racemic pair rac ‐ Y1 exhibited high syndioselectivity ( P r = 0.93) due to polymeric exchange. Ultimately, a series of P3HB products with streamlined tacticity ( P m : 0.07−0.90) was readily prepared by simply adjusting the enantiomeric excess (ee) values of the catalyst. A systematic investigation of the relationship between tacticity and material properties was performed. This work not only establishes an efficient and controllable route to tailor‐made P3HB but also provides a scalable pathway for precise stereocontrol in polymer synthesis.

The effect of carbon nanotube (CNT) doping on the physical and mechanical properties of eco-friendly, natural resin-modified shellac adhesives in metal–metal bonding

Isotope‐Labeled Methanol‐Derived <i>O</i> ‐Alkylisoureas as Versatile and Practical Agents for d ₃ ‐Methylation, ¹³ C‐Methylation, and ¹³ CD ₃ ‐Methylation

ABSTRACT The development of highly efficient and practical methods for the incorporation of stable isotopes into organic molecules are valuable for the pharmaceutical industry. The introduction of deuterium or 13 C atoms can enable the direct tracing of the drug molecule without substantially altering its structure or function, and the introduction of CD 3 ‐ or 13 C‐labeled methyl into drug molecules is one of the most commonly employed methodology. However, the key issue that plagues the current research area is the lack of highly efficient, cheap and practical reagent. Herein, methyl‐d 3 ‐ N,N' ‐diisopropylcarbamimidate (MDIC‐d 3 ), methyl‐ 13 C‐ N,N' ‐diisopropylcarbamimidate (MDIC‐ 13 C) and methyl‐ 13 C‐d 3 ‐ N,N' ‐diisopropylcarbamimidate (MDIC‐ 13 CD 3 ), synthesized via reaction of diisopropylcarbodiimide with the corresponding stable isotope labelled methanols, have been developed for the efficient d 3 ‐methylation, 13 C‐methylation and 13 CD 3 ‐methylation of complex molecules bearing several possible reactive sites with good selectivity, high‐level deuterium and 13 C incorporation, and good functional group tolerance under external base‐free conditions. Additionally, these reagents can also be employed for the highly efficient isotope‐labeled methylation of arenes via palladium‐catalyzed Suzuki–Miyaura type cross‐coupling.

Prediction of ground reaction force waveforms using consumer-grade wearable devices and a convolutional neural network

Proximal Ir–Ir Cooperativity for Reprogramming the CO ₂ ‐to‐DMF Hydrogenation Pathway

ABSTRACT The hydrogenation of CO 2 to N , N ‐dimethylformamide (DMF) with dimethylamine requires the concerted transformation of three distinct substrates, a fundamental kinetic challenge that mononuclear catalysts can only address through high‐barrier, sequential steps. Herein, we demonstrate a ligand‐enabled proximity strategy in binuclear Cp*Ir(III) complexes, wherein the spatial confinement of two metal centers facilitates the concerted activation of multiple substrates. The optimized binuclear architecture, equipped with strategically positioned ‒OH pendants, transforms the rate‐limiting termolecular collision into a kinetically favorable, low‐barrier pathway. This electronic and spatial cooperativity culminates in a turnover number of 1 540 000, placing the catalyst among the most efficient molecular systems reported for DMF production with selectivity approaching quantitative (&gt; 99%). Integrated computational and spectroscopic studies reveal that the dual‐Ir framework mitigates the entropic penalty inherent to termolecular processes, while the hydroxyl functionality polarizes the Ir‒H bond to promote H 2 heterolysis and CO 2 insertion. In situ NMR and infrared spectroscopy directly identify the key Ir–hydride and Ir–formate intermediates, providing experimental validation of the computationally predicted low‐barrier pathway. These findings establish for the first time how multimetallic cooperativity and secondary coordination sphere effects operate in concert to bypass the intrinsic kinetic limitations of single‐site catalysts.

A lead abellaite–alginate nanocomposite as a contrast agent for post-mortem CT imaging

Ligand‐Enabled Chemical‐Potential Modulation of A‐Site Cation Reactivity Stabilizes Tin Halide Perovskite Nanocrystals

ABSTRACT Tin halide perovskite nanocrystals offer a lead‑free platform for optoelectronics, but their practical use is severely hampered by rapid oxidation degradation. However, conventional strategies that strength Sn 2+ participation and stability inevitably face a trade‐off between lattice Sn vacancies (V Sn ) formation and surface Sn 2+ exposure. Here, we move beyond Sn 2+ ‐centric strategies to an A‐site reactivity regulation strategy. By selectively suppressing A‐site cation reactivity, Sn 2+ efficiently incorporates during their crystallization, thereby simultaneously suppressing V Sn formation and lowering surface Sn 2+ exposure. Using CsSnBr 3 nanocrystal as model system, this strategy enables precise control over product composition and crystallization kinetics, yielding nanocrystal films can preserve &gt; 92% of the perovskite phase and 81% of initial emission after 60 h of air exposure. Ligand exchange experiment decouples the surface and lattice effect, confirming the dominant role of lattice V Sn in determining air stability. Extending this strategy to CsSnCl 3 , FASnBr 3 and CsSnI 3 nanocrystals demonstrated its generality across A/X‑site chemistries. This work establishes a new strategy to control vacancy formation and surface redox processes. The ligand‐enabled chemical‐potential modulation provides a general and predictive means to access this control.

Effect of silicon carbide nanoparticles on the morphology, rheological properties, and mechanical performance of polyamide 6/nitrile butadiene rubber nanocomposites

Excited‐State Conformational Dynamics Enables Visible‐Light‐Activated Near‐Infrared Phosphorescent Nano‐Assemblies for Bioimaging

ABSTRACT Visible‐light‐excited near‐infrared ultralong organic phosphorescence (NIR‐UOP), has attracted increasing attention due to its unique advantages. However, the development of efficient NIR‐UOP systems remains challenging. In this study, we propose a rational molecular design strategy to achieve visible‐light‐excited ( λ ex = 450 nm) NIR‐UOP via excited‐state conformational dynamics. The optimized molecule, py‐2mNO 2 , exhibits NIR‐UOP emission at 635 and 700 nm, with a high phosphorescence intensity of 12 cd/m 2 and a lifetime of 268 ms. Mechanistic studies reveal that the dynamic conformational charge transfer facilitates intersystem crossing (ISC). Meanwhile, the relatively flat excited‐state potential energy surface enables the molecule to adopt a planar conformation, thereby suppressing non‐radiative decay through intramolecular attractive interactions. Leveraging these properties, py‐2mNO 2 ‐based nanoparticles were assembled using a polymethyl methacrylate (PMMA) isolation strategy. Consequently, high‐contrast phosphorescence imaging of hypoxic tumors with a signal‐to‐background ratio (SBR) of 39.47 ( λ e x = 365 nm) was achieved using this matrix‐isolated phosphorescent nano‐assembly, which could even be excited with a commercial mobile phone flashlight (SBR = 14.55). This work not only provides a rational design strategy for visible‐light‐excited NIR‐UOP systems but also establishes an efficient nano‐assembly approach for constructing NIR‐UOP nanoparticles suitable for in vivo imaging.

Combined effect of Al2O3 microparticle-enhanced cultivation (MPEC) and inoculation strategy on Streptomyces rimosus

Expanding the Design Rules for Discriminating Nucleic Acid Mutations via Mismatch‐Exchange

ABSTRACT Complementarity between nucleic acids via Watson–Crick base pairing formulates the basic principle for designing hybridization probes but often suffers low sequence selectivity against single nucleotide mutations. Herein, we report mismatch‐exchange as a new design principle that allows the highly sensitive and robust discrimination of single nucleotide polymorphisms (SNPs) by simply manipulating the number and position of mismatches in both probes and the reaction products. Leveraging mismatches to drive the strand‐exchange and finetuning the specificity, mismatch‐exchange is particularly advantageous for analyzing complex nucleic acid targets containing multiple nearby SNPs. Both selective tolerance to synonymous SNPs and OR‐gate‐based detection of clustered drug‐resistant SNPs were demonstrated. Once deployed to nucleic acid testing in clinical settings, mismatch‐exchange enabled the discrimination of multiple lamivudine‐resistant hepatitis B virus mutants in a clinical cohort containing 65 clinical plasma samples.

Comparative evaluation of geostatistical and machine learning approaches for seasonal mapping of soil salinity in agricultural lands

Topological Isomerism of Möbius‐Shaped Aramide Macrocycles Induced by Host‐Guest Interactions

ABSTRACT In contrast to traditional Möbius molecules characterized by fully conjugated backbones, synthetic amide‐linked Möbius‐shaped macrocycles represent a hitherto‐unreported class of topological architectures. Here we report the rational design of the first hydrogen‐bonded Möbius‐shaped aramide macrocycles. Central to this design are intramolecular hydrogen bonds within a para ‐linked aromatic segment, which critically stabilize the conformation and lock the macrocyclic ring into a single‐twist topology. Crystallographic analyses unambiguously confirm their single‐twisted Möbius‐shaped architectures, while LOL‐π calculations support sustained electronic delocalization across the macrocyclic backbones. Notably, a reversible topological switching between a single‐twisted Möbius‐shaped and a planar Hückel‐shaped conformation occurs upon the introduction of water clusters, which occupy the central cavity and competitively disrupt the para ‐linker hydrogen bonds. Furthermore, complexation with chiral amino acids induces characteristic circular dichroism responses, successfully translating host–guest recognition into distinct chiroptical outputs. This work establishes a fully amide‐linked macrocyclic platform that enables stimuli‐responsive interconversion between Möbius‐ and Hückel‐shaped conformations.

RT-DETR-based object detection and parameter extraction for wireless signal spectrograms

A multiscale assessment model for mining-induced groundwater disturbance risk to multi-aquifer and its application in disaster reduction

The pathogenic Candida albicans regulates local vaginal epithelial immunity through the NLRP3/IL-1β pathway in VVC/RVVC mouse models

Abstract Vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis (RVVC) are among the most common infections of the lower genital tract in reproductive-age women. While host immune mechanisms have garnered increasing attention in these infections, the specific underlying mechanisms remain poorly understood. In this study, we compared the immune responses between VVC and RVVC, investigating the immune mechanisms by which Candida albicans affects the host. We established RVVC mouse models using Candida albicans derived from both VVC and RVVC infections, and assessed changes in infection rates, vaginal epithelial histopathology, and inflammation. Additionally, we infected VK2 human vaginal epithelial cells with Candida albicans for RNA sequencing and established a cell model. To explore the underlying mechanisms, we intervened with an NLRP3 inhibitor and performed qPCR, Western blot, and immunofluorescence staining to evaluate the expression of NLRP3 and IL-1β. Moreover, we assessed the expression of pro-IL-1β, cleaved caspase-1, GSDMD-NT, and ASC proteins, and conducted PI staining to evaluate changes in membrane permeability and cell injury. Our results showed that Candida albicans -induced changes in IL-1β were associated with both VVC and RVVC, suggesting that NLRP3-mediated IL-1β secretion may contribute to in modulating host immune responses. Notably, PI staining demonstrated an increased proportion of PI-positive cells, and protein analyses showed elevated expression of ASC, cleaved caspase-1, and GSDMD-NT, consistent with inflammasome activation and increased membrane permeability. Compared with the VVC group, epithelial damage was partially alleviated in the RVVC group, although epithelial thickness remained higher than that in the control group.In conclusion, this study suggests that NLRP3/IL-1β-mediated inflammation is associated with the host immune response in both VVC and RVVC. The increased expression of inflammasome-associated proteins, together with increased PI-positive cells, suggests enhanced membrane permeability and inflammasome-associated cell injury following Candida albicans infection. These findings provide new insights into the inflammatory mechanisms underlying these infections.

Bio-physiological responses to challenging underwater environments: insights from cave divers

An energy efficient reliable machine learning based fuzzy fault tolerant model with self-healing routing in wireless sensor networks

Flow cytometry as a tool for real-time monitoring of antifungal activity and aggregation in Candida auris