Transport Ability Research Articles

Directional Transport of Photogenerated Electrons to Reduction Sites in Covalent Organic Frameworks by Microenvironment Modulation for CO2 Photoreduction

AbstractAs the transfer of photogenerated electrons to CO2 directly determines its reduction performance, it is important to boost the local photogenerated electron density at the reaction site. Herein, a new strategy is demonstrated to evaluate the local photogenerated electron density at the reaction site by modulating the microenvironment of the reaction site at a molecular level based on 3 rationally designed relatively electron‐deficient (ED) and electron‐rich (ER) type COFs. Expectedly, En‐COF‐TAPB‐TDOEB exhibits high photogenerated electron density at the reduction site due to the presence of an additional electric field, whose polarization direction is consistent with that of the basic unit of COFs. As comparison, photogenerated electrons in Am‐COF‐TAPB‐TFB and Pr‐COF‐TFPB‐TAB mostly distribute in benzene and triphenylene, respectively, due to the delay in exciton dissociation and the presence of an electric field with an inverse direction compared with that of the basic unit of the COFs. Consequently, En‐COF‐TAPB‐TDOEB shows superior CO2 photoreduction efficiency to Am‐COF‐TAPB‐TFB and Pr‐COF‐TFPB‐TAB. Further mechanism investigation demonstrates the influence of the polar microenvironment on the excited state and charge separation pathways of the π‐system in En‐COF‐TAPB‐TDOEB, which convincingly confirms that the ability of directional transport of photogenerated electrons to reduction sites in photocatalysts is directly correlated to their activity in CO2 reduction.

Magnetic kirigami dome metasheet with high deformability and stiffness for adaptive dynamic shape-shifting and multimodal manipulation.

Soft shape-shifting materials offer enhanced adaptability in shape-governed properties and functionalities. However, once morphed, they struggle to reprogram their shapes and simultaneously bear loads for fulfilling multifunctionalities. Here, we report a dynamic spatiotemporal shape-shifting kirigami dome metasheet with high deformability and stiffness that responds rapidly to dynamically changing magnetic fields. The magnetic kirigami dome exhibits over twice higher doming height and 1.5 times larger bending curvature, as well as sevenfold enhanced structural stiffness compared to its continuous counterpart without cuts. The metasheet achieves omnidirectional doming and multimodal translational and rotational wave-like shape-shifting, quickly responding to changing magnetic fields within 2 milliseconds. Using the dynamic shape-shifting and adaptive interactions with objects, we demonstrate its applications in voxelated dynamic displays and remote magnetic multimodal directional and rotary manipulation of nonmagnetic objects without grasping. It shows high-load transportation ability of over 40 times its own weight, as well as versatility in handling objects of different materials (liquid and solid), sizes, shapes, and weights.

Effective Dopants Pb and Pb‐SiW12 to Enhance Sb2S3‐Based Photodetector Performance

AbstractSb2S3 has excellent photovoltaic properties, but the performance of its photovoltaic devices still needs to be improved. The main issues hindering its photovoltaic performance are the poor carrier transport ability and the significant charge recombination. Doping strategies play a key role in addressing these issues. This study investigates the effect of Pb(CH3COO)2 (Pb) and [Pb(DMF)7]2[SiW12O40] 2DMF (Pb‐SiW12) doping on the photovoltaic properties of Sb2S3 thin films. It is found that the intensity of diffraction peaks on the (130) crystal plane of Pb‐doped Sb2S3 and the (221) crystal plane of Pb‐SiW12@Sb2S3 is increased, which enhances the crystallinity of the films. Meanwhile, Pb and Pb‐SiW12 doping narrow the bandgap (1.69 eV) of Sb2S3 to 1.65 eV and 1.62 eV. Electrochemical tests show that the carrier concentration and carrier lifetime are increased. The Pb‐doped Sb2S3 photodetector photocurrent of 14 μA, 7 times higher than the 2 μA pristine Sb2S3 photodetector. It exhibits a responsivity of 13.9 mA/W and detectivity of 1.2×1011 Jones. The Pb‐SiW12@Sb2S3 photodetector photocurrent is 11 μA. Pb‐SiW12 can immobilize Pb while reducing the amount of Pb. The methodology in this work provides a way to improve the performance of Sb2S3 thin‐film photodetectors.

The design and preparation of PDI modified NH2-MIL-101(Fe) for high efficiency removal of dimethoate in peroxymonosulfate system: Performance, mechanism, pathway and toxicity assessment

The widespread use of organophosphorus pesticide dimethoate (DMT) in agriculture poses a threat to human health. In this work, the perylene tetracarboxylic diimide (PDI) modified NH2-MIL-101(Fe) (PDI/MIL) with strong covalent bond C(=O)–N were designed and prepared by a step solvothermal method. The synergistic effect between photocatalytic and peroxymonosulfate (PMS) activation for the DMT elimination over PDI/MIL was gained. Interestingly, PDI/MIL(1:10)/PMS showed boosting degradation efficiency (95.6%) for DMT under 18 min simulated sunlight irradiation. Its apparent reaction rate constant was 24.7 times higher than that of NH2-MIL-101(Fe)/PMS. Moreover, its reusability, stability and mineralization ability were evaluated, and a remarkable mineralization rate of 95.3% with 90 min was achieved. The enhanced activity were attributed to the formation of amide bond that exhibited superior charger transport ability and amount of produced active species. Combined the results obtained from the HPLC-MS and molecular structure characteristics of DMT analyzed by Fukui index, the degradation pathways were proposed. The toxicity of intermediates were predicted by Ecological Structure Activity Relationship (ECOSAR), Toxicity Estimation Software Tool (T.E.S.T.), and Vibrio fischeri experiments. Our work provided deep insights into the mechanisms of DMT degradation via photocatalysis-activated PMS over organic semiconductor modified metal organic frameworks.

Thinned g-C3N4 nanosheets with microdopants of cucurbit[7]uril to improve photoelectrochemical water-splitting

Utilizing solar energy to generate hydrogen through photoelectrochemical (PEC) water splitting is considered as the most efficient method and sustainable pathway. Graphitic carbon nitride (g-C3N4), as a candidate for photoelectrochemical catalysts, exhibits the drawbacks including small specific surface area and high complexity of photogenerated electron-hole pairs. With supramolecular encapsulation of melamine guest within cucurbit[7]uril, a new process for thinned and nitrogen-doped g-C3N4-0.04 % nanosheets are developed, and the photoelectrocatalytic activity is obviously improved on the surface. A photocathode with the prepared g-C3N4-0.04 % nanosheets produce more than twice efficiency of pristine g-C3N4 for water splitting, and the incident photon-to-current conversion efficiency (IPCE) is increased by a factor of about 10 under simulated conditions of sunlight at AM 1.5 G (100 mW/cm2). The improved performance should be the results of the thinned layers by introduction of the macrocyclic compound in g-C3N4 nanosheets, which reduce the charge transfer resistance, and inhibit the complexation of the photogenerated electron pairs, to prolong the lifetime of the electron, and facilitate the ability of the electron transport with an increase in current. On the other hand, the specific surface area is improved in the g-C3N4-0.04 % nanosheets to expose more reactive sites, and the microdopant of cucurbit[7]uril provides more active nitrogen sites, to enhance the photocatalysis.

The structure of the porcine uterine-conceptus interface is associated with gestational day, fetal size and sex

This study aimed to characterize histological changes of the maternal-conceptus interface in feto-placental units associated with fetal weight and sex throughout pregnancy. Pregnant Large-White X Landrace gilts(n=18) were euthanized and hysterectomized on gestational days[GDs] 30(n=3), 45(n=5), 60(n=5), and 90(n=5). Intact cross-sections of fetoplacental interface associated with the lightest[LW] and normally-grown[NW] littermates were collected on GD30(n=4 per size). On GDs 45, 60 and 90, interactions between fetal size and sex were investigated in light-weight males[LWM] and females[LWF]; normal-weight males[NWM] and females[NWF] (n=4/group/GD). Fetal weight did not affect the endometrium composition, including relative proportion of glandular epithelium, blood vessels, and connective tissue. Feto-placental units from LW embryos tended to have longer chorioallantoic fold length on GD30(P=0.06). On GD45, higher proportion of larger endometrial glands was observed in NWM, and taller trophoblastic epithelium in NW conceptuses, regardless of sex(P<0.05). NWF presented the greatest proportion of subluminal endometrial epithelial blood vessels(P<0.05). On GD60, more blood vessels were present at the folds’ base in males feto-placental units, whereas taller trophoblastic epithelium were present in NWF fetuses’ feto-placental units(P<0.05). Feto-placental units’ morphological composition throughout gestation in NW and LW conceptuses revealed that fold length was higher as early as GD30, with no further increase up to GD90 in LW conceptuses(P>0.05). Increased proportion of glandular epithelium was observed in LW conceptuses; the highest percentage present on GD90(P<0.05). Collectively, we demonstrated that fetal weight and sex influence the morphological structure of feto-placental units from as early as GD30, suggesting potential differences in the ability for nutrient transport.

Commonalities and Characteristics Analysis of Fluorine and Iodine used in Lithium‐Based Batteries

AbstractAmong optimization strategies for solving the poor ion transport ability and electrolyte/electrode interface compatibility problems of lithium (Li)‐based batteries, halogen elements, such as fluorine (F) and iodine (I), have gradually occupied an important position because of their superb electronegativity, oxidizability, ionic radius, and other properties. The study commences by outlining the shared mechanism by which F and I enhance solid‐state lithium metal batteries' electrochemical performance. In particular, F and I can considerably improve ion transport capacity through chemical means such as intermolecular interactions and halogenation reactions. Furthermore, the utilization of F and I significantly enhances the stability of the electrolyte/electrode interface via physical strategies, encompassing doping techniques, the application of surface coatings, and the fabrication of synthetic intermediate layers. Subsequently, the characteristics of F and I used in Li‐based batteries are elaborated in detail, focusing on the fact that F can provide additional energy density as an anode material but by different mechanisms. Additionally, I can considerably activate dead lithium at the negative electrode, and F can act as a new carrier. Finally, a rational concept of the synergistic effect of F and I is proposed and the feasibility of F–I bihalide solid electrolytes is explored.

OsAMT1.1 knockout-induced decrease in cadmium absorption and accumulation by rice related to cadmium absorption-related gene downregulation

Cadmium (Cd) is a hazardous heavy metal that poses a serious risk to human health through the food chain, with rice being a significant vector because of its tendency to accumulate Cd. Nitrogen (N), an essential element for plant growth, also affects the Cd absorption and accumulation in crops. This study investigated the effects of N application on Cd absorption and accumulation in Cd-contaminated soils. Potting experiment showed that increasing N concentrations significantly increased the plant biomass and Cd contents in rice tissues. Ammonium (NH4+) transporter gene OsAMT1.1 knockout led to a substantial reduction in Cd absorption and accumulation in all rice tissues compared to that in the wild-type plants. Specifically, osamt1.1 mutants increased the Cd content in culm tissues, whereas it was reduced in brown rice. In addition, OsAMT1.1 knockout reduced Cd2+ influx in roots under NH4+-N addition, although OsAMT1.1 lacked Cd transport ability when expressed in yeast. Gene expression analysis revealed that OsAMT1.1 knockout reduced Cd absorption-related genes (OsIRT1, OsNRAMP1, and OsNRAMP5) expression levels. These finding highlight the critical role of N supply and OsAMT1.1 in regulating the Cd content in rice, offering insights into the molecular mechanisms of Cd transportation in plants.

Multifunctional benzoselenadiazole-capped organic molecule-based nanohybrid for efficient asymmetric supercapacitor and oxygen evolution reaction

Nanostructured hybrid materials have attracted significant interest in the field of energy storage and conversion. To investigate the effect of all nanohybrids on electrochemical properties, we have synthesized organic-inorganic nanohybrids through in situ galvanostatic electrodeposition using a monometallic and bimetallic composition of nickel, cobalt salts and an organic molecule. The electrochemical studies reveal that BSeFY/NCDH (20:20) (BSe = benzo[2,1,3]selenadiazole, F = L-phenylalanine and Y = L-tyrosine; NCDH = nickel‑cobalt double hydroxide) hybrid electrode performs more efficiently than 40:0, 0:40, 10:30, 30:10 and nickel‑cobalt double hydroxide-20:20 (NCDH-20:20) electrodes. The specific capacitance of the 20:20 hybrid electrode is measured to be 1338.46 F/g at 2 A/g current density. The AC/NF negative electrode was made using activated carbon, carbon black and polyvinylidene fluoride (PVDF) in a ratio of 80:15:5. The fabricated asymmetric device reveals the energy density of 35.48 Wh/kg at a power density 751.36 W/kg. Furthermore, the device exhibits a capacitance retention of 91.24 % after 5000 cycles at 7 A/g current density. This fabricated device has the ability to illuminate a red LED and operate a small fan. Furthermore, the designed and fabricated hybrid materials are highly efficient for the oxygen evolution reaction (OER). Among the fabricated materials, the 20:20 hybrid electrode is highly active and achieves a lower overpotential of 240 mV with a low Tafel slope of 62 mV/dec at a current density of 10 mA/cm2. Furthermore, the BSeFY/NCDH (20,20) hybrid is highly robust and shows negligible activity loss after 55 h of chronopotentiometry measurement at 10 mA/cm2 current density. Furthermore, multistep chronopotentiometry was performed in the current density range of 4 to 40 mA/cm2 and the results exhibit that the potential rapidly levels off in the next 400 s due to the robust electrochemical stability, rapid mass and electron transportation ability of 20:20 nanohybrid. Therefore, the electrochemical investigations demonstrate that the bimetallic organic-inorganic nanohybrid is highly active in supercapacitor and OER due to its abundant electrochemical active sites, high conductivity, enhanced Faradaic redox properties, multiple valence transitions and the easy synergistic effect between metal ions and organic moiety.

Differentiating Triassic W–Sn ore-bearing and ore-free plutons in the Xitian Ore Field (South China) using apatite geochemistry

Though the metallogenic process of the Xitian W–Sn deposit has been established, the key factors distinguishing Triassic W–Sn ore-bearing granites from ore-free granites remain uncertain, leaving an important gap in understanding the controls on Triassic W–Sn mineralization. In this study, we present a comprehensive investigation of apatite from the Triassic Longshang W–Sn ore-bearing and Goudalan ore-free granites, to trace the nature of parental magma and to provide constraints on the processes related to Triassic W–Sn mineralization in Xitian Ore Field (South China). Apatites from ore-bearing (AOB) granites and apatites from ore-free (AOF) granites exhibit distinct Cathodoluminescence (CL) images: AOB samples feature darker cores and brighter rims, with concentric oscillatory growth zoning in the rim sections, whereas AOF samples exhibit chaotic textures in CL images. The U–Pb age dating of AOB and AOF yield a lower intercept age of 227.3 ± 4.3 Ma (1σ, MSWD = 3.9) and 227.1 ± 7.8 Ma (1σ, MSWD = 2.4) on the Tera-Wasserburg diagrams, respectively. The similar εNd(t) values (−10.91 to −9.82 for AOB; −10.42 to −8.77 for AOF) (expressed as deviation in parts per 10,000 from CHUR composition), relatively low Cl contents (<0.05 wt%), and high F (~3 wt%) of studied apatites, suggest that W–Sn ore-bearing and ore-free granitic magmas were both generated by melting of old continental crust. The texture and high concentration of REE + Y and Th in AOB could be assumed as the result of fluid exsolution. The chaotic texture, broad variation in 147Sm/144Nd ratios, may imply that AOF might have experienced metasomatic modification. Lower Eu/Eu* value together with higher Ce/Ce* value in AOB suggests a more reduced environment for W–Sn ore-bearing granites. Lower Sr, Mg content, and higher Y contents suggest that W–Sn ore-bearing granites have a higher degree of fractionation than ore-free granites. We propose that the mobilization and transport ability of W and Sn by hydrothermal fluids play an important role in the enrichment of W and Sn, and redox state of magma and the degree of magma differentiation determine the final enrichment level of tungsten and tin.

Interfacial Engineering‐Assisted Energy Level Modulation Enhances the Photoelectrochemical Water Oxidation Performance of Bismuth Vanadate Photoanodes

AbstractBiVO4 faces significant challenges for widespread application in photoelectrochemical (PEC) water oxidation due to its poor hole transport ability, high surface defect density, and sluggish water oxidation reaction kinetics. Employing interfacial engineering to assist in energy level modulation is an effective strategy to address these challenges. Herein, a CuCrO2 hole transport layer (HTL) is coupled and further grew NiCo‐MOF in situ to prepare a NiCo‐MOF‐CuCrO2‐BiVO4 composite photoanode. The novel composite photoanode not only achieves a photocurrent density of 5.75 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (vs RHE) but also maintains stable operation for over 24 h. Comprehensive physicochemical characterization and density‐functional theory calculations confirm that the built‐in electric field generated by the p–n heterojunction formed between the CuCrO2 HTL and BiVO4 photoanode enhances the hole transport ability. Moreover, the NiCo‐MOF chelated on the photoanode surface not only passivates the surface defect states but also accelerates the kinetics of the water oxidation reaction. Under the synergistic effect of dual modification, the PEC water oxidation performance of the BiVO4 photoanode is dramatically improved. This pioneering work presents a MOF/HTL/BiVO4 configuration that provides a blueprint for the future development of integrated photoanodes for efficient solar energy conversion.

Core–shell upconversion nanoparticles with suitable surface modification to overcome endothelial barrier

Upconversion nanoparticles (UCNPs), capable of converting near-infrared (NIR) light into high-energy emission, hold significant promise for bioimaging applications. However, the presence of tissue barriers poses a challenge to the effective delivery of nanoparticles (NPs) to target organs. In this study, we demonstrate the core–shell UCNPs modified with cationic biopolymer, i.e., N, N-trimethyl chitosan (TMC), can overcome endothelial barriers. The core–shell UCNP is composed of NaGdF4: Yb3+,Tm3+ (16.7 ± 2.7 nm) as core materials and silica (SiO2) shell. The average particle size of UCNPs@SiO2 is estimated at 26.1 ± 3.7 nm. X-ray diffraction (XRD), transmission electron microscopy (TEM) and element mapping shows the formation of hexagonal crystal structure of β-NaGdF4 and elements doping. The surface of UCNPs@SiO2 has been modified with poly(ethylene glycol) (PEG) to enhance water dispersibility and colloidal stability, and further modified with TMC with the zeta potential increasing from -2.1 ± 0.96 mV to 26.9 ± 12.6 mV. No significant toxic effect is imposed to HUVECs when the cells are treated with core–shell UCNPs with surface modification up to 250 µg/mL. The transport ability of the core–shell UCNPs has been evaluated by using the in vitro endothelial barrier model. Transepithelial electrical resistance (TEER) and immunofluorescence staining of tight junction proteins have been employed to verify the integrity of the in vitro endothelial barrier model. The results indicate that the transport percentage of the UCNPs@SiO2 with PEG and TMC through the model is up to 4.56%, which is twice higher than that of the UCNPs@SiO2 with PEG but without TMC and six times that of the UCNPs@SiO2.

Continuous Electrosynthesis of Pure H2O2 Solution with Medical-Grade Concentration by a Conductive Ni-Phthalocyanine-Based Covalent Organic Framework.

Electrosynthesis of H2O2 provides an environmentally friendly alternative to the traditional anthraquinone method employed in industry, but suffers from impurities and restricted yield rate and concentration of H2O2. Herein, we demonstrated a Ni-phthalocyanine-based covalent-organic framework (COF, denoted as BBL-PcNi) with a higher inherent conductivity of 1.14 × 10-5 S m-1, which exhibited an ultrahigh current density of 530 mA cm-2 with a Faradaic efficiency (H2O2) of ∼100% at a low cell voltage of 3.5 V. Notably, this high level of performance is maintained over a continuous operation of 200 h without noticeable degradation. When integrated into a scale-up membrane electrode assembly electrolyzer and operated at ∼3300 mA at a very low cell voltage of 2 V, BBL-PcNi continuously yielded a pure H2O2 solution with medical-grade concentration (3.5 wt %), which is at least 3.5 times higher than previously reported catalysts and 1.5 times the output of the traditional anthraquinone process. A mechanistic study revealed that enhancing the π-conjugation to reduce the band gap of the molecular catalytic sites integrated into a COF is more effective to enhance its inherent electron transport ability, thereby significantly improving the electrocatalytic performance for H2O2 generation.

Calcium Transport Activity of UV/H2O2-Degraded Fucoidans and Their Structural Characterization.

Calcium-chelated polysaccharides have been increasingly considered as promising calcium supplements. In this study, degraded fucoidans (DFs) with different molecular weights (Mws) were prepared after UV/H2O2 treatment; their calcium-chelating capacities and intestinal absorption properties were also investigated. The results showed that the calcium-chelating capacities of DFs were improved with a decrease in Mw. This was mainly ascribed to the increased carboxyl content, which was caused by free-radical-mediated degradation. Meanwhile, the conformation of DF changed from a rod-like chain to a shorter and softer chain. The thermodynamic analysis demonstrated that DF binding to calcium was spontaneously driven by electrostatic interactions. Additionally, DF-Ca chelates with lower Mw showed favorable transport properties across a Caco-2 cell monolayer and could effectively accelerate the calcium influx through intestinal enterocytes. Furthermore, these chelates also exhibited a protective effect on the epithelial barrier by alleviating damage to tight junction proteins. These findings provide an effective free-radical-related approach for the development of polysaccharide-based calcium supplements with improved intestinal calcium transport ability.

Co-grown novel S-scheme tubular P–UCN/S-TCN homojunction mediates photocatalysis-PMS activation synergistic system for efficient degradation of antibiotic

The low photogenerated carrier separation and transport ability of the photocatalyst are the main factors inhibiting the photocatalytic activity. The construction of composite photocatalysts can effectively improve the efficiency of photogenerated carriers. However, the problem of reduced photocatalyst stability and catalytic activity due to easy separation of unstable composite interfaces has not been well solved for a long time. Therefore, in this work, a co-growth strategy was put forward to thermally co-polymerize sulfur-containing tubular supramolecular precursors with urea in order to achieve the growth of porous g-C3N4 nanoparticles (P–UCN) on the sulfur-doped tubular g-C3N4 (S-TCN), thus to successfully prepare P–UCN/S-TCN homojunction photocatalysts with chemically bonded stable composite interfaces. Furthermore, a coupled photocatalytic-peroxymonosulfate (PMS) activation system was constructed to further promote the photogenerated carrier separation of P–UCN/S-TCN as well as the catalytic activity of the reaction system through the electron donor-acceptor relationship between P–UCN/S-TCN and PMS. Experimental characterization and DFT theoretical calculations together revealed the band gap structural characteristics and the direction of electron flow of the P–UCN/S-TCN S-scheme homojunction, and confirmed the successful construction of a stable chemically bonded homojunction interface. Then the results of catalytic activity test of P–UCN1/S-TCN1 showed a high tetracycline hydrochloride (TCH) degradation efficiency (93.5%) within 30 min, and also demonstrated 100% degradation efficiency for Rhodamine B (RhB). This work made important progress in the design of a novel stable S-scheme homojunction interface and provided a reference for the application of photocatalysis-PMS coupling system in environmental remediation.

P3HT/g-C3N4 composite fiber membranes for high-performance photocatalytic hydrogen evolution

As a superstar semiconducting polymer, poly(3-hexylthiophene) (P3HT) demonstrates high efficiency in carrier transport ability and wide absorption range. However, pristine P3HT exhibits minimal photocatalytic activity as a result of its short carrier transport distance and fast electron-hole recombination. Here, we strategically fabricated P3HT/g-C3N4 composites on polymethyl methacrylate (PMMA) fiber (PTCN) via electrospinning and the physicochemical properties were fully investigated. Raman spectroscopy, ultraviolet–visible (UV–Vis) absorption spectra and X-ray photoelectron spectroscopy (XPS) results demonstrated a well-defined p-n heterojunctions can be formed between P3HT and g-C3N4 molecules through π-π interaction and extended conjugated length of P3HT could be achieved by tuning the ratios of P3HT relative to g-C3N4. The presence of the heterojunctions facilitates the effective disconnection of the electron-hole pairs, resulting in a significantly enhanced photocatalytic hydrogen evolution rate of 7327 μ mol/(h·g) for the PTCN fiber membranes. This value exceeds that of P3HT fibers by 57.7 times and powder g-C3N4 by 6.8 times, respectively. The high photocatalytic hydrogen production activity of P3HT/g-C3N4 fiber membrane expands the application of P3HT. More importantly, these results indicate that the construction of heterojunction fiber materials is a promising approach for improving the photocatalytic ability of conjugated semiconducting polymers.

Mutation of rice SM1 enhances solid leaf midrib formation and increases methane emissions

The leaf midrib system is essential for plant growth and development, facilitating nutrient transport, providing structural support, enabling gas exchange, and enhancing resilience to environmental stresses. However, the molecular mechanism regulating leaf midrib development is still unclear.In this study, we reported a rice solid midrib 1 (sm1) mutant, exhibiting solid leaf aerenchyma and abaxial rolling leaves due to abnormal development of parenchyma and bulliform cells. Map-based cloning revealed that SM1 encodes a litter zipper protein (ZPR). SM1 was mainly expressed in the sheaths and basal midrib and was associated with the nucleus. Further experiments indicated that SM1 can interact with OSHB1, preventing the formation of OSHB:OSHB dimers and subsequently repressing the expression of OSH1 involved in the regulation and maintenance of apical stem meristem formation. The sm1 mutant reduced long-distance oxygen transport ability from shoot to root. The impaired oxygen transport in the sm1 mutant may have contributed to the increase in methanogens and elevated methane emissions. Collectively, our findings revealed that the SM1-OSHB1-OSH1 modules regulate leaf aerenchyma development in rice. These modules not only enhance our understanding of the molecular mechanism of rice leaf aerenchyma development but also offer insights for reducing methane emissions through genetic modification.

Different built-in electric fields for transmission-mode GaAs photocathodes through doping engineering: Design and modeling

In order to enhance the emission performance of transmission-mode GaAs photocathodes used in optoelectronic field, different exponential doping structures are designed for the GaAs emission layer to generate different types of built-in electric fields. These built-in electric fields include the constant, increasing and decreasing types, which can help photoelectron transport toward the emission surface. By solving the one-dimensional continuity equation using the finite difference method, the electron concentration distribution and quantum efficiency of the three types of exponential doping GaAs photocathodes are derived. Meanwhile, the light absorption distributions in the emission layer are simulated by the finite difference time domain method. By comparing the optical absorption distribution and the electron concentration distribution, it is concluded that, among the three types of exponential doping structures, the exponential doping structure generating the increasing built-in electric field has the most sufficient long-wave light absorption capacity and the strongest photoelectron transport ability, thereby achieving the highest quantum efficiency. This theoretical work can help understand the mechanism of improving the photoemission performance of GaAs photocathodes through doping engineering.

Iron mediated n → π* electron transitions and mid-gap states formation in CN under low-temperature secondary calcination enhances photodegradation of organic pollutants

Iron modified carbon nitride (CN) materials have attracted widespread attention from researchers in different application fields. In this paper, single atom iron anchored CN (FeCN) with mid-gap states and n → π* electron transition was synthesized through low temperature secondary calcination. The mid-gap states introduce surface states capable of trapping photogenerated electrons, enabling FeCN to absorb photons with energies lower than its intrinsic optical bandgap. 10%FeCN also exhibits distinct optical absorption above 490 nm derived from the n → π* electron transition, which expand the visible light response range of photocatalysts and enhance electron transport ability. Additionally, the Fe-Nx site enhances the separation and transmission efficiency of photoexcited charges. The prepared 10%FeCN exhibits extremely high photocatalysis and photo-Fenton activity. Mercaptobenzothiazole (MBT) degradation rate of 10%FeCN is 3.47 times higher than CN, achieving a mineralization rate of 86.7% in 100 min. Additionally, the oxytetracycline hydrochloride (OTC) degradation rate of 10%FeCN in photo-Fenton reaction is 11.9 times higher than CN. After five cycles, this catalyst still has good reactivity, indicating its good stability.

Effects of asymmetric rough boundaries on turbulent Rayleigh–Bénard convection

We report on an experimental study of turbulent Rayleigh–Bénard convection with asymmetric top and bottom plates. The plates are covered with pyramid-shaped roughness elements whose aspect ratios are $\lambda =1$ or $\lambda =4$ . In the low-Rayleigh-number regime ( $Ra&lt;1.9\times 10^9$ ), the heat transport efficiencies in the asymmetric cells, characterized by the Nusselt number, are smaller than those measured in a symmetric $\lambda = 1$ cell and are greater than those for a symmetric $\lambda = 4$ cell, whereas in the high-Rayleigh-number regime ( $Ra&gt;1.9\times 10^9$ ), the Nusselt numbers of the asymmetric cells are, in turn, greater than those for the symmetric cell with $\lambda = 1$ and smaller than those for the symmetric cell with $\lambda = 4$ . In addition, the heat transports of individual plates are studied based on the temperature drops across both halves of the cell. In the low- $Ra$ regime, the $\lambda =1$ plate shows higher heat transfer than the $\lambda =4$ plate, while for the high- $Ra$ regime, the $\lambda =4$ plate shows a higher heat transport ability. In both regimes, the individual Nusselt number of the plate with lower heat transfer is insensitive to the topology of the other plate. Besides, it is found that the symmetry of the centre temperature distribution is robust to the symmetry breaking of boundary topographies. For the $Ra$ range explored, a weak temperature inversion is observed in the bulk of asymmetric rough cells. Finally, we remark that the temperature fluctuation at the cell centre and the Reynolds number associated with the large-scale circulation show universal power laws in terms of the flux Rayleigh number as $\sigma _{T_{c}}\sim Ra_F^{0.68}$ and $Re_{LSC}\sim Ra_F^{0.36}$ , respectively.