Browse Articles

Late Miocene speleothems show significant warming, temperate vegetation, and wildfires in Arctic Siberia

Abstract Climate driven northward boreal forest expansion into the tundra biome controlled by permafrost will play a major role in global emissions trajectories. Yet our limited understanding of the interplay between vegetation and permafrost makes predictions of changing boreal forest extent difficult. We analyse fossil pollen, stable carbon isotopes, and lignin and levoglucosan biomarkers from Tortonian speleothems (8.68 ± 0.09 Ma) from the Lena River Delta (N72.27°, E126.94°) in Arctic Siberia to infer palaeotemperature, precipitation, vegetation and fire regimes. The Tortonian provides a potential analogue for near future climate warming under extreme emissions scenarios, with global mean global temperature ca. 4.5°C above modern and atmospheric CO2 concentrations similar to present. We find evidence for a mixed forest regime, capable of maintaining wildfires, in a region currently dominated by tundra. Future transition to a similarly temperate regime would have large-scale impacts on the global carbon cycle.

Solution‐Mediated Photoreversible Switch Between 2D and 3D Hydrogen‐Bonded Organic Frameworks

Abstract In photoresponsive crystalline porous materials, the light‐driven reversible topological transformation is of particular interest, as it can cause an overall change in structure and lead to more drastic switch in material properties, but remains a formidable challenge. Herein, we report a three‐dimensional (3D) hydrogen‐bonded organic framework ( HOF‐OF ) self‐assembled by photochromic diarylethene (DAE) and tetrakis(4‐amidiniumphenyl)methane (TAM) via charge‐assisted hydrogen bonds. Light irradiation drives isomerization of DAE, and the internal strain generated during photoisomerization is released through dissolution and recrystallization, which are accompanied by the breaking and reestablishment of hydrogen bonds. Benefit from the weak and reversible nature of hydrogen bonds as well as the good solution processability of HOFs, solution‐mediated reversible switch between 3D and two‐dimensional (2D) HOF is achieved by ring‐open/ring‐close photoisomerization of the DAE moiety controlled by remotely alternating UV and visible light irradiation. Loading lanthanide complex into HOF enables DAE photoisomerization‐controlled photochromic fluorescence resonance energy transfer process between the lanthanide and DAE moiety, resulting in reversible luminescence on/off switch in the host‐guest, capable of intelligent anti‐counterfeiting in a noninvasive manner.

Optimization of antibacterial and antifungal activities in Moroccan saffron by-products using mixture design and simplex centroid methodology

Spin‐State and Clustering Effects in Fe‐Complex Negolytes for Near‐Neutral Aqueous Redox Flow Batteries

Abstract Cost‐effective redox‐active materials are essential for advancing redox flow batteries (RFBs). Iron, with its abundance and suitability as a redox couple, is a promising candidate; however, achieving stable and fast redox reactions in aqueous RFBs remains a challenge. This study presents an Fe‐based negolyte stabilized by a hexadentate ligand, where Fe–ligand bonds are enhanced through intermolecular interactions. The sulfonate‐substituted Fe complex exhibits a formal potential of −0.44 V versus Ag/AgCl and an exceptionally high rate constant of 0.69 cm s −1 . Near‐neutral RFBs incorporating 0.5 M Fe complex show excellent cycling stability, with no discernible capacity fading over 300 cycles. This performance is attributed to intermolecular hydrogen bonds that reinforce Fe–ligand coordination and promote the formation of stable trimeric clusters. Operando electrochemical Raman spectroscopy and density functional theory reveal that π‐backdonation from Fe(II) to the imino‐phenolate moiety further stabilizes the complex after reduction. In contrast, the hydroxyl‐substituted complex exhibits inferior stability due to weaker hydrogen bonding and less pronounced π‐backdonation. These findings underscore the importance of ligand design and intermolecular interactions in developing cost‐effective, high‐performance redox‐active materials for aqueous RFBs.

Supplementation of a new combination of prebiotic and postbiotic shapes fecal microbiota of old dogs while influencing immune parameters

Abstract Healthy senior dogs were subjected for 77 days to a dietary regime with (or without) prebiotic + postbiotic mixture composed by short-chain fructo-oligosaccharides and yeast fractions (scFOS+). Their fecal microbiota was studied and the links between the microbiota and immune parameters were investigated after Lyme vaccination. All along the study results showed a clear modulation of the microbiota with a higher relative abundance (RA) for Megamonas spp., Bacteroidaceae, Bacteroidetes plebeius, Clostridiales, Phascolarctobacterium, Succinivibrionaceae, Fusobacterium spp. in feces from scFOS + dogs. An amplicon sequence variants (ASVs) index (Enterobacteriaceae + Clostridium spiroforme vs. Fusobacterium + Megamonas) was developed and found significantly different between the groups with scFOS + dogs showing a lower index suggesting a possible modulation of the physico-chemical environment in the gut, favoring the growth of strict anaerobes producing short-chain fatty acids. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) analysis revealed stimulation of propionate and acetate production pathways, vitamin biosynthesis (vitamin B2, B5 and B9 precursors) and pathways related to tricarboxylic acid cycle in the scFOS + group. The RA of several ASVs from Bacteroidetes and Fusobacteria families were found moderately negatively correlated to IgA and IgG concentrations (P < 0.05). In particular, Megamonas and Phascolarctobacterium appeared as interest genera. In summary, scFOS + is a good candidate to support the health of elderly dogs through microbiota changes. Metabolomics or in vitro mechanistic experiments will be crucial to further understand the mechanisms at play.

Proteome‐Wide Ligand and Target Discovery by Using <i>β</i> ‐Nitrostyrene Electrophiles: Supporting Targeted Protein Degradation

Abstract Bioconjugation chemistry has been a powerful avenue in expanding the repertoire of druggable proteome, as well as in identifying new E3 ligases to support targeted protein degradation (TPD). However, a large fraction of proteome remains inaccessible with existing covalent probes. Herein, we incorporated various electron‐withdrawing groups into styrene derivatives and identified β ‐nitrostyrene as a cysteine‐targeting reversible covalent warhead for target discovery. Through phenotypic screening and chemoproteomics platforms, we identified new ligandable sites such as C96 of SND1, C110 of PTGES2, modulating cell proliferation in an acute myeloid leukemia cell line. Moreover, incorporation of this warhead into the BRD4 inhibitor (+)‐JQ1 demonstrated that the covalent handle engages the novel E3 ligase tripartite motif‐containing 28 (TRIM28) at Cys232 residue, thereby promoting the targeted degradation. Notably, when transplanted into other protein‐targeting ligands, the β ‐nitrostyrene warhead effectively induced protein degradation of EGFR L858R/T790M/C797S , PDE5, BTK, LRRK2, and BCR‐ABL/c‐ABL without eliciting a hook effect. Importantly, the degraders demonstrate significantly enhanced antcancer effects compared to corresponding inhibitors. To our knowledge, this is the first report of small‐molecular degraders engaging TRIM28 to support targeted protein degradation, and provides a rational pathway for design and development of potent monovalent degraders.

Probing the Heteroepitaxial Seeded Growth and Self‐Sorting Processes of Segmented Co‐Micelles with Chemically Distinct Crystalline Cores

Abstract The ability to produce uniform micellar nanoparticles with controlled dimension and spatially controlled functionality is a key challenge in nanoscience. Living crystallization‐driven self‐assembly (CDSA) of block copolymers (BCP) has emerged as an effective approach to generate uniform size‐tunable core‐shell micellar nanoparticles; however, most core‐shell micelles generated via CDSA consist of a continuous crystalline core from BCPs with the same core‐forming block. Herein, we perform insightful studies of heteroepitaxial CDSA process from chemical distinct core‐forming poly(ferrocenyldimethylgermane) (PFDMG) and poly(ferrocenyldimethylsilane) (PFDMS) based BCPs to produce segmented block comicelles. The heteroepitaxial growth process produced micelles with kinetically trapped crystalline cores that are thermodynamically less stable than the materials formed via spontaneous nucleation. This was rationalized by determining the previously unknown core lattice of PFDMG micelles, self‐assembly experiments, and theoretical lattice energy calculations, providing an insight into the energetic penalty associated with heteroepitaxial growth. These methods for determining the theoretical core lattice energies in these BCP systems could provide a way to screen BCP candidates that can undergo heteroepitaxial growth. Furthermore, by using our newfound understanding of these micelle systems, we achieved the formation of micelles with crystalline cores that undergo self‐sorting, driven by self‐seeding from fragmented triblock comicellar structures.

Mechanism of First Proton‐Coupled Electron Transfer of Water Oxidation at the BiVO4${\rm BiVO}_4$–Water Interface

Abstract The oxygen evolution reaction (OER) at the –water interface is considered to be the bottleneck of the overall water splitting at this aqueous interface. To provide insight into the mechanism of this reaction, the focus is set on the first proton‐coupled electron transfer (PCET). The free‐energy surface of this first step is obtained by combining on‐the‐fly probability‐enhanced sampling and machine learning potentials at the hybrid functional level of accuracy. Our study reveals that proton transfer precedes electron transfer and determines the reaction barrier, consistent with kinetic‐isotope‐effect experiments. The calculated reaction barrier amounts to eV. The proton moves from the adsorbed water molecule to a surface O atom through a direct transfer mechanism. The hole hopping to the resulting hydroxide occurs via the mediation of a surface Bi atom. The presented framework can be generally applied to other PCET steps and other oxides, thus opening the door to a comprehensive investigation of the OER mechanism at oxide–water interfaces.

Thermal radiation effects on nanofluid flow over a vertical cone in the presence of pressure work

Abstract This study examines the effect of thermal radiation on nanofluid flow and heat transfer over a truncated cone in the presence of pressure work, a problem critical for thermal management and industrial cooling systems. Using similarity transformations, the governing equations are converted into coupled nonlinear partial differential equations and solved numerically via the Legendre collocation method. It gives a high degree of consistency between the proposed numerical solutions and the results previously reported under specific cases. The Prandtl number, pressure work parameter, radiation parameter, and nanoparticle volume fraction all have a major impact on flow and thermal behavior, according to the main results. Nanofluids enhance the transfer of heat by 10–40% when compared to pure fluid, cooling speeds up, and surface strength and hardness improve. Also, the kinds of nanofluid and the parameters related to the volume percentage of nanoparticles are crucial in determining the flow behavior. The surface mechanical properties are advanced by using 10% nanoparticle nanofluid rather than 5%. It has been discovered that the strength and hardness of the surface will enhance with an increase in the pressure work parameter when employing Cu-water nanofluid, but they will decrease with an increase in the thermal radiation parameter values. The novelty of this work lies in the application of the Legendre collocation method to this problem, along with new quantitative insights into how pressure work and radiation interact with nanofluids, providing practical guidelines for optimizing thermal and mechanical performance in industrial systems.

The Doping Effects on the NIR Emission Enhancement of Gold Nanoclusters and the Application in Efficient NIR‐OLED

Abstract Metal nanoclusters (NCs) have emerged as promising near‐infrared (NIR) emissive materials. A series of highly red/NIR luminescent Au–Cu nanoclusters have been synthesized, Au 22‐ x Cu x ( t BuC 6 H 4 C≡C) 18 ( x  = 0–6) ( Au 22‐ x Cu x ). Compared with the parental cluster Au 22 ( t BuC 6 H 4 C≡C) 18 ( Au 22 ), doping effects have been clearly established: the more the amount of doping Cu, the higher photoluminescence quantum yield (PLQY). Remarkable solutions for NIR emission under ambient conditions are found with Au 19 Cu 3 and Au 17.1 Cu 4.9 , and the PLQYs at ∼710 nm are ∼55% and ∼72%, respectively. The study on excited state dynamics of these clusters reveals that the more copper atoms doped, the slower nonradiative decay and the faster intersystem crossing rate, the higher PLQY. Surprisingly, an external quantum efficiency (EQE) of ∼15.43% is achieved from a NIR‐OLED with Au 16 Cu 6 as the emitting layer, showing the prospect of metal NCs in potential applications for NIR‐OLED.

Soybean reproductive physiology as affected by sublethal rates of auxin mimic herbicides

Subcellular and macrostructural immediate responders to airblast traumatic brain injury

Flexible‐Linked Oligomeric Acceptors: Precise Synthesis and Enhanced Photovoltaic/Mechanical Properties for Stretchable Devices

Abstract Intrinsically stretchable organic solar cells (IS‐OSCs) are among the most promising technologies for wearable power applications. However, the development of electron acceptors that simultaneously meet the demands for high performance and mechanical stretchability remains a significant challenge. In this study, we creatively synthesized three oligomeric acceptors with flexible linkers (2YF‐Br, 4YF‐T, and 6YF‐BT) and achieved both high efficiency and mechanical robustness in IS‐OSCs. Benefiting from an improved fibrous morphology and excellent charge dynamics, rigid OSCs based on 4YF‐T demonstrated a superior power conversion efficiency (PCE) of 18.76%, outperforming devices based on 2YF‐Br and 6YF‐BT. Additionally, the thermal stability of rigid OSCs progressively improved with increasing molecular weight, from 2YF‐Br to 6YF‐BT. Furthermore, the enlarged molecular weight of the acceptors significantly enhanced mechanical stretchability, with crack‐onset strain (COS) values of 16.11%, 20.62%, and 25.92% for 2YF‐Br, 4YF‐T, and 6YF‐BT, respectively. Importantly, as molecular weight increased, the mechanical robustness of IS‐OSCs also improved, with 6YF‐BT‐based devices achieving remarkable stretchability (strain at PCE 80%  = 35%). This study introduces a new class of high‐molecular‐weight acceptors with well‐defined structures, paving the way for the advancement and practical application of IS‐OSCs in wearable electronics.

Co‐sustained Release Strategy of Nonflammable Gel Polymer Electrolytes Enables Long‐Life Sodium Metal Batteries

Abstract Sodium metal batteries (SMBs) with gel polymer electrolytes (GPEs) are considered promising candidates for high energy‐density batteries due to their high theoretical capacity and cost effectiveness. However, the intrinsic flammability of GPE poses challenges for their widespread application. Inspired by the concept of the capsules, a triethyl phosphate (TEP)‐based GPE with co‐sustained release effect has been designed. This structure features an insoluble ethoxylated trimethylopropane triacrylate (ETPTA) polymer matrix combined with carbonate co‐solvents, effectively reducing the corrosion of TEP on sodium metal anodes while maintaining a continuous flame‐retardant effect. In this distinctive structure, the abundant carbonyl group on ETPTA promotes the uniform migration of sodium ions, whereas the carbonate co‐solvent facilitates the formation of a NaF‐rich solid electrolyte interphase (SEI) layer, effectively suppressing the growth of sodium dendrite. Low content of TEP guide the preferential orientation of the (100) crystal plane of sodium anode, enhancing the long‐term cycling stability. Na/GPE/Na cells can achieve stable cycling for over 1600 h, and the NVP/GPE/Na full cells exhibit 86.6% capacity retention after 4000 cycles. Moreover, the engineered GPE enables the operation of a 4.5 V high‐voltage cathode for 500 cycles. This strategy paves a new way for designing high‐safety GPE tailored for high‐performance SMBs.

Thio‐Tetracosulene: A Highly Twisted Molecular Plectoneme

Abstract We report the synthesis and characterization of thio‐tetracosulene 3 , a highly twisted chiral macrocycle constructed via sulfur fluorine annulative substitution from a cyclometaphenylene derivative. It is the first macrocyclic aromatic compound with a plectonemic configuration, and the structure is unambiguously confirmed by single crystal X‐ray diffraction study. The two enantiomers of 3 can be resolved to investigate their chiroptical properties. In contrast to the known topological knot‐, or Möbius‐type macrocycles which induce chirality by specific connection patterns, the asymmetric structure of 3 is formed and maintained by the tendency of a ring in distress to reduce unfavorable strains.

The Crucial Role of Oxygen Evolution Reaction in Electrocatalytic Oxidative C─C Bond Cleavage in Lignin Biomass Valorization

Abstract The electrocatalytic oxidative cleavage of the C─C bond is highly effective for converting lignin biomass into high‐value‐added aromatic chemicals. However, the oxygen evolution reaction (OER) at applied oxidative potential usually competes in the aqueous environment. In this study, we found that OER does not entirely hinder the cleavage process but rather acts as a synergistic catalytic step. By using defect‐rich carbon nanotubes as the electrocatalyst and combining experimental and theoretical analysis, we found that the reactive oxygen species (O 2 − ) formed before *O 2 desorption serve as the key oxygen source. These species could interact with the enolate intermediate of lignin, which facilitates the in situ production of aromatic compounds. Under the optimal potential of 0.5 V versus Ag/AgCl, 98.8% of 2‐phenoxyacetophenone is converted into phenol and benzoic acid via C α ─C β bond cleavage, with yields of 62.31% and 43.42%, respectively. Additionally, the depolymerization of quasi‐natural poplar lignin achieves a total monomer yield of up to 12.41 wt%. This study provides new mechanistic insights into C α ─C β bond cleavage during electrocatalytic lignin depolymerization under alkaline conditions, contributing to efficient biomass valorization.

Hematological analysis of alpha-thalassemia: A single-center, retrospective clinical study

Objectives To determine the optimal cutoffs of the three indicators (MCV, MCH and HbA2) for alpha-thalassemia screening and to evaluate the validity of these indicators in Fujian Province, China. Methods We conducted a retrospective analysis on the results of specimens received from May 2016 to April 2023. Receiver operating characteristic (ROC) curves were used to confirm the optimal cutoffs of the screening indicators. And the effectiveness of different combined screening methods was evaluated in patients with and without alpha-thalassemia. Results The optimal cutoffs of MCV, MCH, and HbA2 were 77.85, 27.05 and 2.55, respectively. Among them, the area under the ROC curve of MCH was 0.912, and it was the best of the three parameters used for alpha-thalassemia screening. Conclusions The results can help clinicians and laboratory technicians perform genetic counseling and prenatal diagnosis for patients. It also provide a reference for alpha-thalassemia genotype distributions in our region and the optimal cutoff values of MCV, MCH and HbA2.

Correction: Causes of delays in construction projects in the Province of Aceh, Indonesia

Circumventing Scaling Relations via Gradient Orbital Coupling Promotes Ammonia Electrosynthesis on Cobalt Catalyst

Abstract Highly efficient electrocatalytic nitrate reduction to ammonia (NH 3 ) relies on the balanced activation of various substrates including nitrate and water, but is currently hindered by the inherent scaling relations governing the adsorption of key reaction intermediates, such as *NO and *H. Herein, we develop a strategy to circumvent these limitations by introducing f–d–p gradient orbital coupling in cobalt oxide (Co 3 O 4 ) through Ce doping. Density functional theory calculations indicate that the lattice strain triggered by the dopant redistributes electron density at the Co and O sites, thereby modulating the adsorption strengths of *NO and *H, which favors the production of NH 3 while suppressing hydrogen evolution reaction. It exhibits a faradaic efficiency of 97.8% and a high yield rate of 3423.0 µg h −1 cm −2 under alkaline conditions. Furthermore, Ce/Co 3 O 4 catalyst shows robust performance over a wide range of nitrate concentrations (from 5 to 200 mM) and excellent cycling stability. Our findings also suggest that the gradient orbital coupling approach can be extended to other lanthanide dopants (e.g., Pr and Nd), offering a broadly applicable platform to break scaling relations and improve NO 3 − ‐to‐NH 3 activity on cobalt catalysts.

Evaluation of an alternative positive control strain of Salmonella enterica subsp. enterica serovar Typhimurium for microbial assays

Officially certified microbiological testing methods utilize positive control strains to enhance experimental reproducibility and ensure standardized procedures among experimenters. Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028 is designated as a positive control strain for microbiological testing by the International Organization for Standardization, the Korean Pharmacopoeia, and Ministry of Food and Drug Safety (MFDS) foodborne investigation methods. However, using such foreign strains involves complicated import procedures and significant financial burdens. In this study, we aimed to select a domestic isolate strain that can replace S. Typhimurium ATCC 14028. The target strains used were S. Typhimurium strains preserved in the Korean Culture Collection for foodborne pathogens (MFDS). To confirm the equivalent characteristics between the candidate strains and the positive control strain, biochemical and molecular characterization were performed according to the methods specified in ISO test methods, the Food Code, and the MFDS food poisoning investigation methods. After biochemical and molecular biological analyses on 19 S. Typhimurium strains, only those exhibiting equivalent characteristics underwent whole-genome sequencing. In the biochemical characterization, two strains showed different results in the citrate utilization test. Excluding these, the remaining 17 strains were subjected to molecular analysis (PCR), and all showed identical genetic profiles to the positive control strain. Ultimately, whole-genome sequencing of the 17 selected candidate strains revealed that strains 1004022 and 1004023 shared the same sequence type (ST19) as S. Typhimurium ATCC 14028, exhibited fewer than 20 SNPs, and showed 99.94% genomic homology. Therefore, S. Typhimurium MFDS 1004022 and 1004023 were proposed as suitable domestic alternative to the imported strain. It is anticipated that the distribution of these alternative strains to microbiological testing laboratories will contribute to food safety management by supporting microbial testing and analysis.