Screening and Mechanism Exploration of Non-Noble Metal Ni3M Catalysts for Propane Dehydrogenation: The Excellence of Synergistic Effects.

The development of cost-effective and anti-coking catalysts for propane dehydrogenation (PDH) is crucial. Here, non-noble metal-incorporated Ni-based catalysts (Ni3M, M = Sc, Ti, V, Mn, Fe, Co, Cu, Zn, Ga, Zr, Nb, Mo, In, Sn) were employed in the PDH process. The introduction of V, Nb, and Mo, with their strong carbon binding ability, created unique Ni-M cooperative sites, enhancing the catalytic performance. Other non-noble metals influenced the electronic structure of Ni, affecting the overall catalytic behavior. V and Nb exhibited a balanced combination of activity, selectivity, and stability, making them potential catalyst candidates. Microkinetic simulations revealed that Ni3V and Ni3Nb displayed high selectivity toward olefins with low apparent activation energies. This study emphasizes the significance of bimetallic synergy in enhancing PDH performance and provides new directions for the development of efficient alkane dehydrogenation catalyst development.

"Microflower-Templated" Janus Sheets: Synthesis and Application in Stabilizing Foams.

In this study, we proposed a method for fabricating Janus sheets using biological "microflowers" as a sacrificial template. The microflower-templated Janus sheets (MF-JNSs) were employed as a foam stabilizer in foam separation of the whey soybean protein (WSP). The MF-JNSs took inorganic hybrid microflowers (BSA@Cu3 (PO4)2-MF) as template, followed by the sequential attachment of protamine and silica to the surface of the BSA@Cu3(PO4)2-MF. Subsequently, the template was removed using ethylenediaminetetraacetic acid after the silicon dioxide was modified by 3-(methacryloyloxy) propyl trimethoxysilane. Upon template dissolution, the modified silica layer, lacking support from the core, fractured to form the MF-JNSs. This method omitted the step of treating the hollow ball by external force and obtained Janus sheets in one step, indicating that it was simple and feasible. The morphology, structure, and composition of the MF-JNSs were analyzed by SEM, TEM, AFM, XRD, and FT-IR. The MF-JNSs were found to delay the breakage time of the Pickering emulsion, demonstrating their emulsion stabilizing capability. Importantly, they significantly enhanced the foam half-life and foam height of soybean whey wastewater (SWW). Moreover, the recovery percentage and enrichment ratio of WSP, separated from SWW by foam separation, were improved to 81 ± 0.28 and 1.20 ± 0.05%, respectively.

Phytochemicals against Osteoarthritis by Inhibiting Apoptosis.

Osteoarthritis (OA) is a chronic joint disease that causes pathological changes in articular cartilage, synovial membrane, or subchondral bone. Conventional treatments for OA include surgical and non-surgical methods. Surgical treatment is suitable for patients in the terminal stage of OA. It is often the last choice because of the associated risks and high cost. Medication of OA mainly includes non-steroidal anti-inflammatory drugs, analgesics, hyaluronic acid, and cortico-steroid anti-inflammatory drugs. However, these drugs often have severe side effects and cannot meet the needs of patients. Therefore, safe and clinically appropriate long-term treatments for OA are urgently needed. Apoptosis is programmed cell death, which is a kind of physiologic cell suicide determined by heredity and conserved by evolution. Inhibition of apoptosis-related pathways has been found to prevent and treat a variety of diseases. Excessive apoptosis can destroy cartilage homeostasis and aggravate the pathological process of OA. Therefore, inhibition of apoptosis-related factors or signaling pathways has become an effective means to treat OA. Phytochemicals are active ingredients from plants, and it has been found that phytochemicals can play an important role in the prevention and treatment of OA by inhibiting apoptosis. We summarize preclinical and clinical studies of phytochemicals for the treatment of OA by inhibiting apoptosis. The results show that phytochemicals can treat OA by targeting apoptosis-related pathways. On the basis of improving some phytochemicals with low bioavailability, poor water solubility, and high toxicity by nanotechnology-based drug delivery systems, and at the same time undergoing strict clinical and pharmacological tests, phytochemicals can be used as a potential therapeutic drug for OA and may be applied in clinical settings.

An Unprecedented Metal Distribution in Silica Nanoparticles Determined by Single-Particle Inductively Coupled Plasma Mass Spectrometry.

Metal-containing nanoparticles are now common in applications ranging from catalysts to biomarkers. However, little research has focused on per-particle metal content in multicomponent nanoparticles. In this work, we used single-particle inductively coupled plasma mass spectrometry (ICP-MS) to determine the per-particle metal content of silica nanoparticles doped with tris(2,2'-bipyridyl)ruthenium(II). Monodispersed silica nanoparticles with varied Ru doping levels were prepared using a water-in-oil microemulsion method. These nanoparticles were characterized using common bulk-sample methods such as absorbance spectroscopy and conventional ICP-MS, and also with single-particle ICP-MS. The results showed that averaged concentrations of metal dopant measured per-particle by single-particle ICP-MS were consistent with the bulk-sample methods over a wide range of dopant levels. However, the per-particle amount of metal varied greatly and did not adhere to the usual Gaussian distribution encountered with one-component nanoparticles, such as gold or silver. Instead, the amount of metal dopant per silica particle showed an unexpected geometric distribution regardless of the prepared doping levels. The results indicate that an unusual metal dispersal mechanism is taking place during the microemulsion synthesis, and they challenge a common assumption that doped silica nanoparticles have the same metal content as the average measured by bulk-sample methods.

Alloyed Trimetallic Nanocomposite as an Efficient and Recyclable Solid Matrix for Ideonella sakaiensis Lipase Immobilization.

In this work, a trimetallic (Ni/Co/Zn) organic framework (tMOF), synthesized by a solvothermal method, was calcinated at 400 and 600 °C and the final products were used as a support for lipase immobilization. The material annealed at 400 °C (Ni-Co-Zn@400) had an improved surface area (66.01 m2/g) and pore volume (0.194 cm3/g), which showed the highest enzyme loading capacity (301 mg/g) with a specific activity of 0.196 U/mg, and could protect the enzyme against thermal denaturation at 65 °C. The optimal pH and temperature for the lipase were 8.0 and 45 °C but could tolerate pH levels 7.0-8.0 and temperatures 40-60 °C. Moreover, the immobilized enzyme (Ni-Co-Zn@Lipase, Ni-Co-Zn@400@Lipase, or Ni-Co-Zn@600@Lipase) could be recovered and reused for over seven cycles maintaining 80, 90, and 11% of its original activity and maintained a residual activity >90% after 40 storage days. The remarkable thermostability and storage stability of the immobilized lipase suggest that the rigid structure of the support acted as a protective shield against denaturation, while the improved pH tolerance toward the alkaline range indicates a shift in the ionization state attributed to unequal partitioning of hydroxyl and hydrogen ions within the microenvironment of the active site, suggesting that acidic residues may have been involved in forming an enzyme-support bond. The high enzyme loading capacity, specific activity, encouraging stability, and high recoverability of the tMOF@Lipase indicate that a multimetallic MOF could be a better platform for efficient enzyme immobilization.

AGC kinases OXI1 and AGC2-2 regulate camalexin secretion and disease resistance by phosphorylating transporter PDR6.

Plant transporters regulating the distribution of secondary metabolites play critical roles in defending against pathogens, insects, and interacting with beneficial microbes. The phosphorylation of these transporters can alter their activity, stability, and intracellular protein trafficking. However, the regulatory mechanism underlying this modification remains elusive. In this study, we discovered two Orthologs of mammalian PKA, PKG, and PKC (AGC) kinases, Oxidative signal-inducible 1 (OXI1) and its closest homologue, AGC subclass 2 member 2 (AGC2-2; 75% amino acid sequence identity with OXI1), associated with the extracellular secretion of camalexin and Arabidopsis (Arabidopsis thaliana) resistance to Pseudomonas syringae and Botrytis cinerea. These kinases can undergo in vitro kinase reactions with three Pleiotropic drug resistance (PDR) transporters: PDR6, PDR8, and PDR12. Moreover, our investigation confirmed PDR6 interaction with OXI1 and AGC2-2. By performing LC-MS/MS and parallel reaction monitoring, we identified the phosphorylation sites on PDR6 targeted by these kinases. Notably, chitin induced PDR6 phosphorylation at specific residues, namely S31, S33, S827, and T832. Additional insights emerged by expressing dephosphorylated PDR6 variants in a pdr6 mutant background, revealing that the target residues S31, S33, and S827 promote PDR6 efflux activity, while T832 potentially contributes to PDR6 stability within the plasma membrane. The findings of this study elucidate partial mechanisms involved in the activity regulation of PDR-type transporters, providing valuable insights for their potential application in future plant breeding endeavors.

Spatio-temporal microbial regulation of aggregate-associated priming effects under contrasting tillage practices.

Tillage intensity significantly influences the heterogeneous distribution and dynamic changes of soil microorganisms, consequently shaping spatio-temporal patterns of SOC decomposition. However, little is known about the microbial mechanisms by which tillage intensity regulates the priming effect (PE) dynamics in heterogeneous spatial environments such as aggregates. Herein, a microcosm experiment was established by adding 13C-labeled straw residue to three distinct aggregate-size classes (i.e., mega-, macro-, and micro-aggregates) from two long-term contrasting tillage histories (no-till [NT] and conventional plow tillage [CT]) for 160 days to observe the spatio-temporal variations in PE. Metagenomic sequencing and Fourier transform mid-infrared techniques were used to assess the relative importance of C-degrading functional genes, microbial community succession, and SOC chemical composition in the aggregate-associated PE dynamics during straw decomposition. Spatially, straw addition induced a positive PE for all aggregates, with stronger PE occurring in larger aggregates, especially in CT soil compared to NT soil. Larger aggregates have more unique microbial communities enriched in genes for simple C degradation (e.g., E5.1.3.6, E2.4.1.7, pmm-pgm, and KduD in Nitrosospeera and Burkholderia), contributing to the higher short-term PE; however, CT soils harbored more genes for complex C degradation (e.g., TSTA3, fcl, pmm-pgm, and K06871 in Gammaproteobacteria and Phycicoccus), supporting a stronger long-term PE. Temporally, soil aggregates played a significant role in the early-stage PEs (i.e., < 59 days after residue addition) through co-metabolism and nitrogen (N) mining, as evidenced by the increased microbial biomass C and dissolved organic C (DOC) and reduced inorganic N with increasing aggregate-size class. At a later stage, however, the legacy effect of tillage histories controlled the PEs via microbial stoichiometry decomposition, as suggested by the higher DOC-to-inorganic N and DOC-to-available P stoichiometries in CT than NT. Our study underscores the importance of incorporating both spatial and temporal microbial dynamics for a comprehensive understanding of the mechanisms underlying SOC priming, especially in the context of long-term contrasting tillage practices.

Enhancing tomato disease resistance through endogenous antifungal proteins and introduced nematode-targeting dsRNA of biocontrol agent Bacillus velezensis HS-3.

BACKGROUND: As a type of biological control agent (BCA), Bacillus velezensis possesses the efficacy of inhibiting pathogenic microorganisms, promoting plant growth, and overcoming continuous cropping obstacles (CCOs). However, there is limited reporting on the optimization of the cultivation conditions for such biocontrol agents and their role as double-stranded RNA (dsRNA) delivery vectors. RESULTS: In this study, a Bacillus velezensis strain HS-3 was isolated from the root zone of tomato plants with in vitro anti-Botrytis cinerea activity. The investigation into active compounds revealed that HS-3 predominantly employs proteins with molecular weights greater than 3 kDa for its antifungal activity. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis identified various proteases and chitosanase, further suggesting that HS-3 most likely employs these enzymes to degrade fungal cell walls for its antifungal effect. To optimize the production of extracellular proteins, fermentation parameters for HS-3 were systematically optimized, leading to an optimized medium (OP-M). HS-3 cultured in OP-M demonstrated enhanced capacity to assist tomato plants in withstanding CCOs. However, the presence of excessive nematodes in diseased soil resulted in the disease severity index (DSI) remaining high. An RNA interference mechanism was further introduced to HS-3, targeting the nematode tyrosine phosphatase (TP) gene. Ultimately, HS-3 expressing dsRNA of TP in OP-M effectively assisted tomatoes in mitigating CCOs, reducing DSI to 2.2% and 17.8% of the control after 45 and 90 days of growth, respectively. CONCLUSION: The advantages of Bacillus velezensis in crop disease management and the mitigation of CCOs become even more pronounced when utilizing both optimized levels of endogenous enzymes and introduced nematode-targeting dsRNA. © 2024 Society of Chemical Industry.

UCST-Type Soluble Immobilized Cellulase: A New Strategy for the Efficient Degradation and Improved Recycling Performance of Wastepaper Cellulose.

This paper reports an innovative study that aims to address key issues in the efficient recycling of wastepaper cellulose. The research team utilized the temperature-responsive upper critical solution temperature (UCST) polymer P(NAGA-b-DMA) in combination with the LytA label's affinity for choline analogs. This innovative approach enabled them to successfully develop a novel soluble immobilized enzyme, P(NAGA-b-DMA)-cellulase. This new enzyme has proven highly effective, significantly enhancing the degradation of wastepaper cellulose while demonstrating exceptional stability. Compared with the traditional insoluble immobilized cellulase, the enzyme showed a significant improvement in the pH, temperature stability, recycling ability, and storage stability. A kinetic parameter calculation showed that the enzymatic effectiveness of the soluble immobilized enzyme was much better than that of the traditional insoluble immobilized cellulase. After the immobilization reaction, the Michaelis constant of the immobilized enzyme was only increased by 11.5%. In the actual wastepaper degradation experiment, the immobilized enzyme was effectively used, and it was found that the degradation efficiency of wastepaper cellulose reached 80% of that observed in laboratory conditions. This novel, thermosensitive soluble immobilized cellulase can efficiently catalyze the conversion of wastepaper cellulose into glucose under suitable conditions, so as to further ferment into environmentally friendly biofuel ethanol, which provides a solution to solve the shortage of raw materials and environmental protection problems in the paper products industry.

Photochemical Mechanisms of Hydroxyquinoline Benzimidazole: Insights from Electronic Structure Calculations and Nonadiabatic Dynamics Simulations.

Excited-state intramolecular double proton transfer (ESIDPT) has received much attention because of its widespread existence in the life reactions of living organisms, and materials with this property are significant for their special luminescent properties. In this work, the complete active space self-consistent field (CASSCF) and OM2/multireference configuration interaction (OM2/MRCI) methods have been employed to study the static electronic structure calculations of the photochemistry and the possibility of ESIDPT process of hydroxyquinoline benzimidazole (HQB) molecule, along with the nonadiabatic dynamics simulations. The computational results show that the HQB molecule is relaxed to the S1-ENOL minimum after being excited to the Franck-Condon point in the S1 state. Subsequently, during the nonadiabatic deactivation process, the OH···N proton transfer and the twisting of benzimidazole occur before arriving at the single proton transfer conical intersection S1S0-KETO. Finally, the system can either return to the initial ground-state structure S0-ENOL or to the single proton transfer ground-state structure S0-KETO, both of which have almost the same probability. The dynamics simulations also show that no double proton transfer occurs. The excited-state lifetime of HQB is fitted to 1.1 ps, and only 64% of the dynamic trajectories return to the ground state within the 2.0 ps simulation time. We hope the detailed reaction mechanism of the HQB molecule will provide new insights into similar systems.

A novel photo-enzyme platform based on non-metallic modified carbon nitride for removal of bisphenol A in water.

A nonmetallic composite photocatalyst with 2D/2D structure was prepared by hydrothermal in-situ polymerization and used for the immobilization of cytochrome C (Cyt c). The photo-enzyme coupling system has a very high enzyme load, which can reach 528.29 mg g-1 after optimization. Compared with free Cyt c, Cytc/PEDOT/CN showed better enzymatic activity, stability and catalytic efficiency. Even after being stored at 100 °C for 60 min, the enzyme activity remained at 49.42 % and remained at 57.89 % after 8 cycles. Moreover, Cytc0.5/PEDOT3/CN showed excellent photocatalytic degradation performance in the degradation experiment of bisphenol A (BPA), reaching 68.22 % degradation rate within 60 min, which was 3.9 times higher than that of pure g-C3N4 and 1.61 times higher than that of pure PEDOT3/CN. This study shows that the introduction of conductive polymers is of great significance to the photo-enzyme coupling system and provides a new strategy for the treatment of phenol-containing wastewater.

A miniprotein receptor electrochemical biosensor chip based on quantum dots.

Recently protein binders have emerged as a promising substitute for antibodies due to their high specificity and low cost. Herein, we demonstrate an electrochemical biosensor chip through the electronic labelling strategy using lead sulfide (PbS) colloidal quantum dots (CQDs) and the unnatural SARS-CoV-2 spike miniprotein receptor LCB. The unnatural receptor can be utilized as a molecular probe for the construction of CQD-based electrochemical biosensor chips, through which the specific binding of LCB and the spike protein is transduced to sensor electrical signals. The biosensor exhibits a good linear response in the concentration range of 10 pg mL-1 to 1 µg mL-1 (13.94 fM to 1.394 nM) with the limit of detection (LOD) being 3.31 pg mL-1 (4.607 fM for the three-electrode system) and 9.58 fg mL-1 (0.013 fM for the HEMT device). Due to the high sensitivity of the electrochemical biosensor, it was also used to study the binding kinetics between the unnatural receptor LCB and spike protein, which has achieved comparable results as those obtained with commercial equipment. To the best of our knowledge, this is the first example of using a computationally designed miniprotein receptor based on electrochemical methods, and it is the first kinetic assay performed with an electrochemical assay alone. The miniprotein receptor electrochemical biosensor based on QDs is desirable for fabricating high-throughput, large-area, wafer-scale biochips.

Chloroplast display of subunit vaccines and their efficacy via oral administration.

As a safe and natural "capsule," plants have several advantages over mammals and microorganisms for the production of oral vaccines. In this study, we innovatively utilized the transmembrane region of the pea Translocase of chloroplast 34 (TOC34) protein to display two subunit vaccines, capsid protein VP2 of Porcine parvovirus (PPV) and the heat-labile enterotoxin B (LTB) of Escherichia coli, on the surface of chloroplasts. Unlike microbial display techniques, chloroplast display circumvents antigen degradation in the stomach while retaining the size characteristic of microorganisms. Additionally, a co-expressed peptide adjuvant, antimicrobial peptide protegin-1 (PG1), was used to enhance the strength of oral immunization. Immunohistochemistry and trypsin digestion of chloroplast surface proteins confirmed the successful localization of both antigens on the chloroplast surface. In stable transgenic tobacco plants, the expression level of VP2-TOC34 ranged from 0.21 to 6.83 µg/g FW, while LTB-TOC34 ranged from 2.42 to 10.04 µg/g FW. By contrasting the digestive characteristics of plant materials with different particle sizes, it was observed that plant materials with diameters around 1 mm exhibited more prominent advantages in terms of chloroplast release and antigen exposure compared to both larger and smaller particles. Oral immunization resulted in significantly increased levels of specific IgG and secretory IgA in the mice compared to the control, with similar effects observed between the groups receiving oral immunization alone and those receiving a combination of initial injection and subsequent oral immunization. Challenge experiments further demonstrated the effective protection against infection in mice using this approach. These findings highlight the potential of chloroplast display technology for the development of effective oral vaccines.

Temperature-Sensitive Janus Particles PEG/SiO2/PNIPAM-PEA: Applications in Foam Stabilization and Defoaming.

The current study presents a scalable approach for the preparation of temperature-responsive PEG/SiO2/PNIPAM-PEA Janus particles and, for the first time, investigates their potential applications in stabilizing foam and defoaming by adjusting the temperature. The method utilizes a (W1 + O)/W2 emulsion system, which incorporates appropriate surfactants to stabilize the emulsion and prevent rapid dissolution of the hydrophilic triblock polymer PEG-b-PTEPM-b-PNIPAM in water. The PEG/SiO2/PNIPAM-PEA Janus particles with temperature-responsive characteristics were synthesized in a single step that combined the sol-gel reaction and photoinduced free radical polymerization. The contact angle of the hydrophilic PEG/SiO2/PNIPAM surface was measured to be 54.7 ± 0.1°, while the contact angle of the hydrophobic PEA surface was found to be 122.4 ± 0.1°. By incorporating PEG/SiO2/PNIPAM-PEA Janus particles at a temperature of 25 °C, the foam's half-life is significantly prolonged from 42 s to nearly 30 min. However, with an increase in temperature to 50 °C, the foam's half-life rapidly diminished to only 44 s. This innovative application effectively enhances foam stabilization at low temperatures and facilitates the rapid dissipation of foam at high temperatures.

Role of the Hippo pathway in autoimmune diseases.

The immune system is an important defense against diseases, and it is essential to maintain the homeostasis of the body's internal environment. Under normal physiological conditions, the steady state of the immune system should be sustained to play normal immune response and immune function. Exploring the molecular mechanism of maintaining immune homeostasis under physiological and pathological conditions will provides understanding of the pathogenesis of autoimmune diseases, infections, metabolic disorders, and tumors, as well as new ideas and molecular targets for the prevention and treatment of these diseases. Hippo signaling pathway can not only regulate immune cells such as macrophages, T cells and dendritic cells, but also interact with immune-related signaling pathways such as NF-kB signaling pathway, TGF-ß signaling pathway and Toll-like receptor signaling pathway, so as to resist the internal environment disorder caused by the invasion of exogenous pathogenic microorganisms and maintain the internal environment stability and physiological balance of the body. Hippo signaling pathway is also involved in the pathological process of immune system-related diseases such as rheumatoid arthritis, inflammatory bowel disease and psoriasis. Hippo pathway is closely related to organ development, stem cell biology, regeneration, and tumor biology. It affects cell differentiation by participating in extracellular and intracellular physiological signal reactions, sensing cell environment, and coordinating cell reactions. This pathway is crucial in maintaining immune homeostasis. This review summarizes the mechanism of Hippo pathway in different immune cells and some autoimmune diseases and the interaction between different immune signaling pathways and Hippo signaling pathway. It aims to explore the role of Hippo in autoimmune diseases and provide theoretical and practical basis for the treatment of autoimmune diseases through Hippo signaling pathway.

Amorphous-crystalline phase transition and intrinsic magnetic property of nickel organic framework for easy immobilization and recycling of ß-Galactosidase.

This work describes the synthesis of fibrous nickel-based metal organic framework (Ni-ZIF) via simple solvothermal method. The material formed was calcinated at 400, 600, 800 °C to improve its surface area, porosity and enzyme binding capacity. Changes in X-ray diffraction pattern after calcination revealed the Ni-ZIF transitioned from amorphous to crystalline structure. The surface area, pore volume and pore size for Ni-ZIF@600 were found to be 312.15 m2/g, 0.88 cm3/g and 10.28 nm, with an enzyme loading capacity of 593.85 mg/g after 30 h The free (ß-Gal-LEH) and immobilized ß-Galactosidase were stable at pH 7.5, temperature 50 °C, and yielded 70.70 and 63.95 mM glucose after milk lactose hydrolysis, respectively. The Ni-ZIF@600@ß-Gal-LEH exhibited high enzyme retention capacity, maintaining 59.44 % of its original activity after 6-cycles. The enhanced magnetic property, enzyme binding capacity and easy recoverability of the calcinated Ni-ZIF could guarantee its industrial significance as immobilization module for enzyme-mediated catalysis.

Influence of labor migration on rural household food waste in China: Application of propensity score matching (PSM).

Food waste has emerged as a critical global concern, with households identified as major contributors to this pressing issue. As the world grapples with sustainability challenges, addressing food waste in the context of rural labor migration is crucial for achieving broader sustainable development goals. However, there is still limited research regarding the relationship between labor migration and food waste. We utilized propensity score matching to analyze cross-sectional data collected from 1270 rural households in China. Labor migration led to significant increases of 37% in overall food waste and 35% in plant-based food waste, respectively. Furthermore, households with labor migration exhibited 29%, 31%, and 30 % higher energy, protein, and carbohydrate waste, respectively, compared to non-migration households. Regarding micronutrients, migration led to a 39% increase in iron waste, a 42% increase in zinc waste, and a 47% increase in selenium waste. The results of the categorical analysis indicate variations in the impact of labor migration on food wastage within rural households. Food wastage in rural households with chronic illness patients responds differently to labor migration. Moreover, labor migration predominantly affects households without courier services in villages, where dietary diversity plays a significant role. Understanding these variations is essential for crafting targeted interventions and policies to address food waste in different rural contexts. The policy implications of our study are crucial for addressing food waste and advancing sustainable development in rural China, where labor migration plays a significant role.

Mechanistic insights into photoinduced energy and charge transfer dynamics between magnesium-centered tetrapyrroles and carbon nanotubes.

Functionalizing single-walled carbon nanotubes (SWNTs) with light-harvesting molecules is a facile way to construct donor-acceptor nanoarchitectures with intriguing optoelectronic properties. Magnesium-centered bacteriochlorin (MgBC), chlorin (MgC), and porphyrin (MgP) are a series of tetrapyrrole macrocycles comprising a central metal and four coordinated aromatic or antiaromatic five-membered rings linked by methine units, which show excellent visible light absorption. To delineate the effects of the aromaticity of coordinated rings on the optoelectronic properties of the nanocomposites, the photoinduced energy and charge transfer dynamics between Mg-centered tetrapyrroles and SWNTs are explored. The results show that excited energy transfer (EET) can occur within MgP@SWNT ascribed to the stabilization of the highest occupied molecular orbital (HOMO) in MgP with the increase of aromatic coordinated rings, while only electron transfer can take place in MgBC@SWNT and MgC@SWNT. Non-adiabatic dynamics simulations demonstrate that electron and hole transfer from MgP to SWNT is asynchronous. The electron transfer is ultrafast with a timescale of ca. 50 fs. By contrast, the hole transfer is significantly suppressed, although it can be accelerated to some extent when using a lower excitation energy of 2.2 eV as opposed to 3.1 eV. Further analysis reveals that the large energy gaps between charge-donor and charge-acceptor states play a crucial role in regulating photoexcited state relaxation dynamics. Our theoretical insights elucidate the structure-functionality interrelations between Mg-centered tetrapyrroles and SWNTs and provide a comprehensive understanding of the underlying charge transfer mechanism within MgP@SWNT nanocomposites, which paves the way for the forthcoming development of SWNT-based photo-related functional materials with targeted applications.

Near-Infrared Dual-Emission of a Thiolate-Protected Au42 Nanocluster: Excited States, Nonradiative Rates, and Mechanism.

Both DFT and TD-DFT methods are used to elaborate on the excited-state properties and dual-emission mechanism of a thiolate-protected Au42 nanocluster. A three-state model (S0, S1, and T1) is proposed with respect to the results. The intersystem crossing (ISC) process from S1 to T1 benefits from a small reorganization energy due to the similar geometric structures of S1 and T1. However, the ISC process is suppressed by relatively small spin-orbit coupling resulting from the similarity of the electronic structures of S1 and T1. As a result of the counterbalance, the ISC rate is comparable with the fluorescence emission rate. In the T1 state, the phosphorescence emission prevails the reverse ISC process back to the S1 state. Taken together, fluorescence and phosphorescence are achieved simultaneously. The present work provides deep mechanistic insights to aid the rational design of NIR dual-emissive metal nanoclusters.

A novel immobilized horseradish peroxidase platform driven by visible light for the complete mineralization of sulfadiazine in water.

A novel immobilized enzyme driven by visible light was prepared and used for complete mineralization of antibiotics in water bodies. The immobilized enzyme was composed of carbon nitride modified by biochar (C/CN) and horseradish peroxidase (HRP), establishing the photo-enzyme coupling system with synergistic effect. Among them, the introduction of biochar not only improves the stability and loading capacity of the enzyme, but also improves the light absorption capacity and carrier separation efficiency of the photocatalyst. After the optimization of immobilization process, the solid load of HRP could reach 251.03 mg/g, and 85.03 % enzyme activity was retained after 18 days of storage at 4 °C. In the sulfadiazine (SDZ) degradation experiment, the degradation rate of HRP/C3/CN reached 71.21 % within 60 min, which was much higher than that of HRP (2.33 %), CN (49.78 %) and C3/CN (58.85 %). In addition, under the degradation of HRP/C/CN, the total organic carbon (TOC) removal rate of SDZ reached 53.14 %, which was 6.47 and 1.74 times that of CN and C3/CN, respectively. This study shows that the introduction of biochar is of great significance to the photo-enzyme cascade coupling system and provides a new strategy for the application of HRP&g-C3N4 system in wastewater treatment.