The principle "hard acids prefer hard bases" from the Hard and Soft Acid-Base (HSAB) theory, has gained extensive validation. However, the interaction mechanisms between borderline acid metals and hard base groups remain unclear, limiting the rational design of highly selective adsorption. This study systematically investigates the synthesis of hard base-functionalized UiO-66 materials (UiO-66-X, X = -NH2, -OH, and -COOH) and their efficacy in adsorbing borderline acid metal (Cu(II), Co(II), Ni(II), Pb(II)). Comprehensive characterization confirms the preservation of the parent framework and the successful introduction of functional groups. Batch adsorption experiments reveal that the solution pH and the pairing between functional groups and metal ions are critical factors affecting adsorption capacity and selectivity. The -OH group exhibits strong affinity for Cu(II), Co(II), and Pb(II), -COOH for Pb(II) and Cu(II), and -NH2 is exceptionally selective for Ni(II). The mechanism, elucidated through XPS and DFT calculations (ESP, DOS, and adsorption energy), verifies coordination between metal ions and the N/O atoms of hard base groups. Additionally, the introduction of -COOH groups through para-functionalization improves the adsorption rate and selectivity per functional group by modulating the electronic structure. This study provides fundamental insights into the structure-activity relationship, aiding in the design of highly selective MOF-based adsorbents.
The plant root system dynamically grows and senses stress, especially phytotoxic heavy metals (HMs), which threaten plant growth and human health through food contamination. Agricultural soils act as reservoirs and pathways for HMs, with accumulation intensified by human activities, including industrial discharges, mining, and heavy use of agrochemicals. Persistent HMs, including cadmium, lead, chromium, and arsenic, alter soil properties, disrupt microbes, and impair nutrient cycling. Strategies to reduce HM stress in plants include nanomaterials, noted for their high reactivity and tunability. Nano-selenium (nano-Se), a trace element, shows promise in regulating plant stress tolerance. Evidence indicates that nano-Se reduces HM uptake and translocation by strengthening antioxidant defenses and modulating rhizosphere and hormonal processes, thereby enhancing root growth, microbial activity, and nutrient-water uptake under metal stress. This review summarizes recent advances in nano-Se signaling, focusing on rhizosphere chemistry and plant-microbe interactions, and examines their potential for sustainable crop growth in HM-polluted soils.
Catalytic radical halogen atom transfer (XAT) typically follows the bond dissociation free energy (BDFE)-dependent reactivity order R-I > R-Br > R-Cl, leaving abundant alkyl chlorides largely underutilized. We report diazaphosphinyl radicals (NHP•) derived from N-heterocyclic phosphines as efficient organic radical catalysts that invert this trend, enabling catalytic hydrodehalogenation of alkyl chlorides over bromides and iodides. Comprehensive thermodynamic, kinetic, and mechanistic studies reveal dual roles of NHP derivatives: XAT abstractors and hydrogen donors. The overall catalytic efficiency is governed not by the radical XAT step, but by a polar bond-metathesis process that regenerates the active P-H reductant (NHP-H). This step is thermodynamically much favorable for chlorides, due to the strong Si-Cl bond formed, thereby establishing a closed catalytic cycle uniquely effective for R-Cl substrates. The catalyst exhibits good functional-group tolerance and enables mono-dechlorination of dichlorides with high selectivity, as well as hydroalkylation of activated olefins. This work highlights the important roles of polar steps in radical catalysis that can dictate substrate selectivity, and provides a sustainable, metal-free strategy for valorizing alkyl chlorides.
Psychiatric settings are high-risk environments for violence. Coercive measures (CMs) and security technologies (STs) can be used to ensure safety. However, limited evidence exists on how Italian mental health nurses (MHNs) perceive the appropriateness of such practices and the influencing factors. This study aimed to fill this gap. Cross-sectional study. An online survey collected sociodemographic data and validated measures of depression, anxiety, stress, stigma toward mental illness, and humanization of care. The perceived appropriateness of various CMs and STs was rated on a 5-point Likert scale using a validated item set. Data were analyzed using descriptive statistics, bivariate tests, and multilevel mixed-effects linear regression. A total of 707 MHNs participated in the study. CMs were considered moderately appropriate (mean = 3.56 ± 0.92), with pharmacological restraint and locked-door policies rated as more appropriate than physical restraint. STs were evaluated better (mean = 3.74 ± 0.95), with alarms and closed-circuit television judged more appropriate than body-worn cameras and metal detectors. CMs were considered less appropriate by non-believers (p = 0.009), head nurses (p < 0.001), and those in non-acute settings (p = 0.004), and more appropriate by those in Central Italy (p = 0.036), on daytime shifts (p = 0.042), and with higher stigma (p = 0.012). STs were considered less appropriate by males (p = 0.004), head nurses (p = 0.040), and more experienced MHNs (p < 0.001), and more appropriate by those in Southern Italy (p < 0.001) and in non-acute settings (p < 0.001). MHNs consider CMs and STs moderately appropriate. Perceptions are influenced by both individual and contextual factors. Targeted training, anti-stigma education, and inclusive policies are needed to ensure ethical and evidence-based safety practices in psychiatric care. Targeted education and training in mental health nursing, both continuing and post-graduate, are essential to support cultural change among MHNs and ensure the appropriate use of CMs and STs. Integrating anti-stigma initiatives and involving MHNs in policy development can strengthen clinical decision-making and foster safer, more ethical, and person-centred psychiatric care.
Macallisterite, a functional material with excellent properties, is widely used in industries. However, the rapid synthesis of high-purity macallisterite with both high yield and uniform morphology remains challenging due to the complex polymerization of borate species during the production process. Herein, we propose a novel magnesium ion-induced strategy for the efficient synthesis of macallisterite by combining sonochemistry assistance and additive method. The polymerization mechanism of borate species under excess magnesium salts was investigated using Raman spectroscopy and DFT. It has been shown that chloride magnesium is the optimal inducer for the macallisterite synthesis as Cl- exhibits lower electrostatic interaction and spatial steric hindrance than SO42- and NO3-. Sonochemical assistance significantly accelerated the nucleation and crystallization of macallisterite through kinetic conditions created by cavitation effects. Accordingly, the crystallization is promoted achieving a maximum yield of 97.92%. Raman and DFT study revealed that Mg2+ ions can effectively induce the formation of the stable neutral complex cluster [Mg(H2O)4(B6O7(OH)6)] in the supersaturated solution, which lowers the reaction activation energy through charge transfer and coordination. Furthermore, dense macallisterite spherulites with uniform morphology and high purity can also be achieved by using sodium dodecyl sulfonate (SDS) as additive. Based on these findings, this study not only elucidates a metal ion-induced crystallization mechanism but also establishes an efficient, green, and scalable synthetic route for high-quality macallisterite.
Nanoparticle films are ubiquitous thermal and electrocatalysts, yet their operando characterization remains challenging. Vibrational sum-frequency generation (vSFG) spectroscopy offers unique advantages due to its high sensitivity and surface specificity, but its application to systems with such intermediate length scale disorder, particularly with phase-resolved detection, has been challenging. In this study, we describe an approach to phase-resolved vSFG spectroscopy of nanoparticle films using z-cut α-quartz as a local reference. We show, by analysis of an octadecyltrichlorosilane film on quartz under the ppp polarization condition, that quantitative detection of absolute phase is possible and subsequently apply this protocol to a film of Mn-doped Co3O4 nanoparticles. Two OH species are resolved (∼3585 and ∼3770cm-1), both oriented H-up relative to the surface. This approach delivers a practical, internally referenced, phase-resolved vSFG methodology for nanoparticle ensembles on dielectric supports and, therefore, offers operando access to catalytic interfaces beyond metallic or plasmonically enhanced systems.
Hydrogen diffusion plays a key role in hydrogen-metal interactions and is closely linked to embrittlement in steels. In iron-based alloys, the influence of local atomic environments on hydrogen diffusion is well recognized, whereas the role of alloy composition remains unclear. Fe-Cr binary alloys, therefore, provide a simple and well-defined model system to isolate the effect of Cr on hydrogen diffusion in iron lattices. In this work, hydrogen diffusion in Fe-Cr alloys is investigated using first-principles calculations based on density functional theory. Ab initio molecular dynamics simulations are further employed to evaluate the influence of Cr concentration on hydrogen diffusion coefficients. The results show that hydrogen diffusion in Fe-Cr alloys is strongly suppressed compared with bcc Fe. This suppression is primarily attributed to higher migration energy barriers resulting from strong Fe-Cr interactions and more compact local atomic packing. Charge transfer analysis demonstrates that hydrogen behaves as an electron acceptor, and the amount of charge transferred is inversely related to the migration barrier. In the disordered solid-solution models, the hydrogen diffusion coefficient decreases with increasing Cr content in the low-Cr range, whereas in the ordered alloy models it exhibits a non-monotonic dependence on composition, with a minimum near 25 at. % Cr. These results reveal the electronic and structural origins of composition-dependent hydrogen diffusion in Fe-Cr alloys at the atomic scale.
The wetting behavior of hydrophobic nanoporous materials plays a pivotal role in advanced technologies such as energy storage, molecular separations, catalysis, and biomimetic systems. A central challenge in employing these materials is the precise control of wetting (intrusion) and dewetting (extrusion) pressures. To address this, we investigated how varying the concentration of organic linkers in ZIF-7-8 (composed of Zn-methylimidazole and benzimidazole) influences the intrusion-extrusion behavior of water within its micropores. Remarkably, we noticed that even a minor substitution of organic linkers (below 3%) led to significant and systematic changes in the wetting properties. Owing to the small fraction of substituted linkers, such effect could not be explained by classical models that consider individual cages. To elucidate this phenomenon, we combined experiments with molecular dynamics simulations and stochastic modeling of the crystallites. Our results reveal that the introduction of alien linkers perturbs the hydrogen-bond network, thereby disrupting the cooperative effects fundamental to the intrusion-extrusion process.
ConspectusTraditional metal nanoparticles have been widely utilized as heterogeneous catalysts in both fundamental scientific research and industrial applications. Their catalytic performances are commonly statistical and represent averaged results from all of the nanoparticles due to their inherent size polydispersity and structure heterogeneity. Recently, metal clusters (1-2 nm) with precise compositions and well-defined structures have provided opportunities to precisely correlate the catalytic properties with the structure and composition of the clusters at the atomic level. Specifically, the distinct metal core, interface, and surface structures of these clusters render them ideal for exploring the contributions of the surface/interface/core of cluster-based catalysts to catalytic properties.In this Account, we introduce the correlation of the catalytic properties of clusters with their ligand, interface, and metal kernel, ultimately mapping out the key factors that dictate the catalytic activity and selectivity. We first preview atomically precise clusters and the structural characteristics of the surface, interface, and kernel. Then, we emphasize the modulation of catalytic properties of cluster catalysts through the ligand, interface, and core. (i) Surface ligand: An efficient surface modification via ligand exchange is able to not only remarkably enhance the catalytic activity but also effectively modulate the product selectivity. (ii) Metal-ligand interface and cluster-cluster interface: The metal-ligand interface can enable the catalytic sites to directly control the whole catalytic process through the synergy between the metal atom and the ligand. Additionally, the interfaces between the clusters and their surrounding environment can cooperatively tailor the catalytic activity and selectivity. (iii) Metal core: The one-atom variation in the cluster kernel composition can effectively tune the overall electronic structures of clusters, thereby indirectly improving their catalytic activities. Furthermore, the central atom within an open core can also act as the active site to directly participate in and facilitate the catalytic reaction. Ultimately, looking to the future of catalysis science, there are still many challenges, but atomically precise metal clusters deserve more future efforts to unravel fundamental catalysis. Therefore, we offer several perspectives on the future research of precise catalysis using atomically precise cluster catalysts. We anticipate that this Account can provide fundamental insight into the unique contributions of the surface/interface/core of heterogeneous catalysts to their overall catalytic performances. By learning these fundamental principles, we will ultimately be able to design high-performance catalysts for a variety of catalytic processes.
This study focuses on the challenge of converting ZnO films into uniform zeolitic imidazolate framework-8 (ZIF-8) layers or membranes, an essential key step in shaping metal-organic frameworks (MOFs). It compares two ZnO deposition techniques: atomic layer deposition (ALD) and physical vapor deposition (PVD), examining how each method affects the surface chemistry of ZnO and its subsequent conversion into ZIF-8. The investigation includes contact angle measurements using methanol and water to assess surface wettability as well as X-ray diffraction (XRD) analysis combined with electronic microscopy to characterize the resulting ZIF-8 layers. The study indicates that ALD ZnO films are more hydrophilic, with a water contact angle of ∼75°, compared to the more hydrophobic PVD films, which exhibit a contact angle of ∼98°. XRD analysis reveals that PVD films display a pronounced (002) crystal orientation, while ALD films consist of randomly oriented nanocrystals. To optimize the conversion of ZnO to ZIF-8, the methanol-to-water ratio was adjusted, with a 3:1 mixture yielding the most uniform ZIF-8 layers. Additionally, thermal treatment of PVD films at 600 °C significantly altered their surface reactivity and conversion behavior, leading to distinct ZIF-8 morphologies. In contrast, ALD films exhibited a higher conversion efficiency, producing continuous, well-crystallized ZIF-8 layers with minimal defects. This improved performance is attributed to their superior surface wettability and reactivity. These findings underscore the critical role of ZnO surface chemistry in ZIF-8 formation and emphasize the importance of optimizing both deposition methods and conversion conditions to achieve high-quality MOF layers.
Performance deterioration in the electrocatalytic hydrogenation (ECH) of concentrated biomass platform molecules remains a major obstacle for practical implementation, largely due to an incomplete understanding of concentration-dependent mechanisms. Using the 5-hydroxymethylfurfural reduction reaction (HMFRR) as a model system, we uncover an unanticipated role of intermolecular hydrogen bonding under high reactant concentrations as revealed by constant-potential DFT calculations and AIMD simulations. Guided by this mechanistic insight, we develop a cation-modulation strategy and identify Li+ ion as the most effective promoter of HMFRR, via a synergistic combination of (i) disruption of intermolecular hydrogen bonds in HMF dimers enabled by the small ionic radius, deep penetration into the inner Helmholtz plane and low coordinated structure of Li+, (ii) enhanced *H transfer arising from its strong electron-withdrawing character, and (iii) preservation of high HMFRR selectivity at moderate Li+ concentrations. Experimental electrochemical measurements and 1H nuclear magnetic resonance (1H NMR) spectroscopy validate these predictions. This work resolves a long-standing challenge in high-concentration ECH and establishes a generalizable paradigm for upgrading concentrated biomass-derived platform molecules through rational interfacial engineering.
This work presents a facile, metal-free, and atom-economical synthesis of pyrimido[2,1-a:4,3-a']diisoquinolines via an acid-promoted formal [2 + 2 + 1 + 1] annulation of readily available 1,2,3,4-tetrahydroisoquinoline and arylglyoxal monohydrates. This annulation proceeds through an azomethine ylide intermediate, achieving the direct N-H/α-C(sp3)-H difunctionalization of 1,2,3,4-tetrahydroisoquinolines and concurrent formation of multiple C-C and C-N bonds. The resulting polycyclic scaffolds are readily transformed into multifunctional photoluminescent materials that display aggregation-induced delayed fluorescence (AIDF) emission. Preliminary biological evaluation revealed that several derivatives potently inhibit key inflammatory mediators in lipopolysaccharide-activated macrophages, indicating their potential as promising anti-inflammatory lead candidates.
Empasiprubart (ARGX-117) is a humanized recycling antibody that prevents binding of C2 to C4b, blocking downstream classical and lectin pathways of complement activation. Empasiprubart binds to the CCP2 domain of complement component C2 in a calcium- and pH-dependent manner, leveraging physiological differences between blood and endosomal environments to facilitate the release and subsequent degradation of bound C2. The molecule incorporates Fc region mutations (H433K and N434F) that enhance its affinity for the neonatal Fc receptor (FcRn) under acidic endosomal conditions, thereby prolonging its in vivo half-life and supporting its recycling capacity. However, despite the earlier description of the complex structure, the molecular mechanism underlying these dependencies has remained elusive. Here, we further explored the crystal structure of the empasiprubart fragment antigen-binding (Fab) complexed to a C2 fragment, and provide a molecular rationale for its unique properties, while recognizing that not all contributing factors have been fully elucidated. Our observations indicate that the pH-dependent target release is rooted in a subtle intramolecular complementarity-determining region (CDR) destabilization, rather than direct modulation of the binding interface, and highlight the interplay between framework residues and CDRs. Collectively, our results not only lead to a better understanding of the mode of action of empasiprubart but also demonstrate the pivotal role of framework residues in the orchestration of antibody CDR function for non-trivial target binding.
Axially coordinated multichromophoric assemblies provide an effective platform for modulating electronic communication through metal-ligand interactions. Herein, we report the synthesis and comprehensive structural, photophysical, electrochemical, and computational investigation of four axially bonded 3-pyrrolyl BODIPY-metalloporphyrin conjugates comprising two Zn(II) porphyrin dyads and two Sn(IV) porphyrin triads. X-ray analysis of the Zn(II) dyads reveals distinct tilted and nearly orthogonal BODIPY-porphyrin geometries. The dyads show partial fluorescence quenching, which, together with a favorable spectral overlap, an excited-state lifetime of τ ≈ 1.63 ns, and uphill electron transfer (ΔG ≈ +0.18 eV), supports a Förster resonance energy transfer pathway. In contrast, the Sn(IV) triads exhibit ultrafast fluorescence quenching (τ ≈ 0.49 ns) and thermodynamically favorable charge separation (ΔG ≈ -0.16 eV). Triads show complementary EPR evidence under dark conditions consistent with a charge-separated intermediate, supporting photoinduced electron transfer. Electrochemical studies show distinct redox processes for the dyads, whereas the triads display broadened reduction features indicative of enhanced electron and charge delocalization. DFT calculations show a systematic decrease in the HOMO-LUMO gap from 2.34 to 1.14 eV. These results establish clear structure property relationships governing energy and electron transfer processes in axially coordinated 3-pyrrolyl BODIPY-metalloporphyrin assemblies.
Hookworm infections continue to impose a substantial burden on human and animal health, but the early host responses that influence parasite establishment are not fully characterized. Experimental models that reproduce key features of hookworm biology and host-parasite interactions remain essential for advancing translational research. In this study, we examined hematological, biochemical, immunological, and parasitological parameters during the acute phase of experimental hookworm infection using the Ancylostoma ceylanicum-Mesocricetus auratus model, a small-animal system widely employed for mechanistic studies of hookworm infection. Animals were evaluated at 7 and 20 days post-infection. Hematological indices and serum iron concentrations did not differ between infected and control groups during the acute phase. In contrast, infected animals showed increased splenic mass at 20 days post-infection, indicating immunological activation. Hepatic hepcidin expression was markedly reduced, suggesting an early alteration in systemic iron regulation. Analysis of inflammatory mediators revealed selective modulation of cytokine expression, with reduced interleukin-6 transcript levels at 20 days post-infection, whereas tumor necrosis factor alpha expression remained unchanged. Parasitological analyses demonstrated progressive parasite establishment, with fecal egg output detected from 14 days post-infection and reaching approximately 300 eggs per gram by day 18, consistent with the onset of patency. Taken together, these data indicate that acute hookworm infection induces coordinated changes in immune responses and iron metabolism before the development of overt hematological alterations.
Dry electroencephalography (EEG) electrodes with low noise and minimal potential drift are crucial for daily wearable and high-density noninvasive brain-computer interfaces. In this study, a Na-doped vertical graphene dry electrode with a diameter of 2.8 mm was prepared to construct a 512-lead ultrahigh-density EEG cap and wireless 8- and 32-lead EEG headbands. The Na-doped vertical graphene layer has a three-dimensional architectural structure that absorbs sweat from the scalp and converts it into an Na+-mediated solid electrolyte, electrically connecting the device to the scalp. The optimized graphene dry electrodes exhibited low scalp-contact resistance (dry: 3.8-6.5 kΩ, H2O: 4.5 kΩ), self-noise (11.1 μV), DC offset voltage (15.6 mV), and potential drift (189.9 μV). The EEG cap, composed of 512 dry graphene electrodes, recorded different rhythm signals with a high signal-to-noise ratio, demonstrating excellent repeatability and long-term stability over 103 days. In addition, a task-state strategy was designed that combined the intensity ratio of fast and slow waves with frequency-domain event-related potentials, demonstrating the reliability of dry electrode headband systems for rapid attention analysis during daily wear. This wearable metal-doped vertical graphene dry-electrode device, especially the 512-lead ultrahigh-density dry-electrode EEG cap, holds promise for applications in brain function research, neuroimaging, and brain-computer interface control.
Ultrathin metal-organic layers (MOLs) have emerged as a type of promising two-dimensional (2D) platforms for artificial photosynthesis, yet their activity is frequently limited by rapid recombination of photogenerated carriers in presence of structural symmetry. Hence, switching on the reactivity through breaking geometric symmetry to create unsymmetric active sites remains a significant challenge. Herein, we demonstrate a switching strategy via one-atom substitution to construct two isostructural ultrathin MOLs with distinct coordination symmetry at the iron active site. Single-crystal x-ray diffraction and spectroscopic analyses reveal that symmetry breaking at the iron site in the MOL effectively enhances CO2 adsorption and facilitates photogenerated carrier separation. Under visible-light irradiation, the MOL with unsymmetrical sites achieves an exceptional CO production amount (ca. 21.20 mmol·g-1), which is as high as 15.8 times more than that of its symmetrical counterpart. Time-resolved transient absorption spectroscopy corroborated by DFT calculations indicates that symmetry breaking not only accelerates the separation and transport of photogenerated charge carriers, but also lowers the Gibbs free energy of CO2 adsorption. This work elucidates how the atomically precise modification of local coordination symmetry switches the photocatalytic performance in an 'off/on' manner and provides a viable design strategy toward emerging 2D materials for artificial photosynthesis.
Heteroatom substitution is a promising strategy to enhance hydrogen evolution reaction (HER) activity of MoS2, yet synergistically activating both its basal plane and edge sites remains challenging. Herein, we report a dual-site substitution of both Mo and S with tellurium in the MoS2 lattice (Te-MoS2), which achieves a superior large-current-density HER performance in acidic electrolyte, surpassing all previously reported single-element-doped MoS2 with nonmetal or non-precious metal. The Te-MoS2 catalyst requires an overpotential of only 364 mV to achieve an industrial-level current density of 1000 mA·cm-2, significantly lower than 506 mV required by commercial 20 wt% Pt/C, and maintains this performance stably for 200 h without decay. Comprehensive analyses reveal that the simultaneous substitution of Mo and S with Te atoms activates neighboring S atoms and also promotes the formation of smaller, edge-rich MoS2 nanosheets, thereby generating abundant basal plane and edge S active sites with optimized hydrogen adsorption energy.
Developing gel polymer electrolytes (GPEs) is a promising strategy to mitigate safety concerns caused by the leakage of liquid electrolytes in lithium metal batteries (LMBs). However, fabricating a membrane with high thermal stability, whose derived GPE also maintains good electrochemical performance, remains a major challenge. Herein, we report a composite membrane, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/poly(m-phenylene isophthalamide) (PMIA), with excellent thermal stability and uniform nanoporous structure for high-performance GPE of LMBs. The PVDF-HFP/PMIA composite membrane, featuring a uniform pore size of 110 nm, is prepared by a double-sided solvent-nonsolvent exchange process via microfluidic technique. The incorporation of PMIA achieves the enhanced heat resistance of the composite membrane with a superior size retention of 86% after continuous heating at 250 °C for more than 360 min. The PVDF-HFP/PMIA GPEs-based Li||Li symmetric cells display stable voltage across various current densities and cycles for 600 h at 0.5 mA cm-2. Moreover, the morphology of the lithium anodes after 100 h shows uniform lithium deposition, demonstrating excellent suppression of lithium dendrite growth. The Li||LFP cells assembled with PVDF-HFP/PMIA-based GPEs deliver a high discharge capacity of 134.5 mAh g-1 at 5 C. The as-prepared heat-resistant GPEs membrane thus offers great potential for improving the safety performance of LMBs.