Band Structure Engineering of Transition-Metal-Based Layered Double Hydroxides toward Photocatalytic Oxygen Evolution from Water: A Theoretical–Experimental Combination Study

Considerable attention has been focused on layered double hydroxides (LDHs) for their applications in solar energy storage and conversion recently, but the in-depth investigation on the semiconducting properties of LDHs is limited. Herein, the electronic properties (band structure, density of states (DOS), surface energy, and band edge placement) of 14 kinds of M^II_<i>n</i>M^III/IV–A–LDHs (M^II = Mg, Co, Ni, Cu, Zn; M^III = Cr, Fe; M^IV = Ti; <i>n</i> = 2, 3, 4; A = Cl^–, NO₃^–, CO₃^2–) which contain transition-metal cations as well as their thermodynamic reaction mechanism toward the oxygen evolution reaction (OER) were studied using a density functional theory plus U (DFT + U) method. The calculation results indicate that the (003) plane is the most preferably exposed surface, and all these calculated LDHs are visible light responsive. The OER driving force and overpotential for these LDHs were obtained via their band edge placement and thermodynamic mechanism, and the results show that 10 of the calculated 12 LDHs (Ni₂Ti–Cl–, Cu₂Ti–Cl–, Zn₂Ti–Cl–, Ni₂Cr–Cl–, Zn₂Cr–Cl–, Co₂Fe–Cl–, Ni₂Cr–NO₃–, Ni₂Cr–CO₃–, Ni₃Cr–Cl–, and Ni₄Cr–Cl–LDHs) can overcome the reaction barriers by virtue of their driving force of photogenerated hole. Experimental observations further prove that Ni_<i>n</i>Cr–A–LDHs (<i>n</i> = 2, 3, 4; A = Cl^–, NO₃^–, CO₃^2–) are efficient OER photocatalysts, among which Ni₂Cr–Cl–LDH shows the most active photocatalytic OER performance (O₂ generation rate 1037 μmol h^–1 g^–1). In the meantime, Mg₂Cr–Cl–LDH has no OER activity, agreeing well with the theoretical prediction. This work provides theoretical insight into the photocatalytic OER performance of LDHs materials which contain transition-metal cations with semiconducting property, which would show potential application in optical/optoelectronic field

DataSheet_1_Design of a multi-epitope vaccine against goatpox virus using an immunoinformatics approach.docx

IntroductionGoatpox, a severe infectious disease caused by goatpox virus (GTPV), leads to enormous economic losses in the livestock industry. Traditional live attenuated vaccines cause serious side effects and exist a risk of dispersal. Therefore, it is urgent to develop efficient and safer vaccines to prevent and control of GTPV.MethodsIn the present study, we are aimed to design a multi-epitope subunit vaccine against GTPV using an immunoinformatics approach. Various immunodominant cytotoxic T lymphocytes (CTL) epitopes, helper T lymphocytes (HTL) epitopes, and B-cell epitopes from P32, L1R, and 095 proteins of GTPV were screened and liked by the AAY, GPGPG, and KK connectors, respectively. Furthermore, an adjuvant β-defensin was attached to the vaccine’s N-terminal using the EAAAK linker to enhance immunogenicity.ResultsThe constructed vaccine was soluble, non-allergenic and non-toxic and exhibited high levels of antigenicity and immunogenicity. The vaccine’s 3D structure was subsequently predicted, refined and validated, resulting in an optimized model with a Z-value of -3.4. Molecular docking results demonstrated that the vaccine had strong binding affinity with TLR2(-27.25 kcal/mol), TLR3(-39.84 kcal/mol), and TLR4(-59.42 kcal/mol). Molecular dynamics simulation results indicated that docked vaccine-TLR complexes were stable. Immune simulation analysis suggested that the vaccine can induce remarkable increase in antibody titers of IgG and IgM, higher levels of IFN-γ and IL-2.ConclusionThe designed GTPV multi-epitope vaccine is structurally stable and can induce robust humoral and cellular immune responses, which may be a promising vaccine candidate against GTPV.</p

Preparation of Oriented Layered Double Hydroxide Film Using Electrophoretic Deposition and Its Application in Water Treatment

Oriented Mg/Al−NO3-layered double hydroxide (LDH) films have been fabricated by the electrophoretic deposition method (EPD) on aluminum substrate, which can be used to remove heavy metal ion and anionic dye from aqueous solutions. The LDH films with thickness of ∼4 μm by EPD method show a high degree of c-orientation of the LDH platelets (the ab-plane parallel to the substrate) and strong adhesion to the substrate confirmed by XRD and SEM. The sorption kinetics of the LDH film for Cr(VI) and Remazol Brilliant Blue R dye (RBBR) was appropriately described by the pseudo-second-order model. Sorption isotherms for Cr(VI) and RBBR by the LDH film were studied, which can be fitted by the Langmuir model more satisfactorily than by the Freundlich model. It was found that the sorption capacity (qMAX) reached ∼79.4 mg g−1 for Cr(VI) and ∼222 mg g−1 for RBBR respectively, much larger than that of the corresponding LDH powder sample (∼67.6 mg g−1 for Cr(VI) and ∼192.3 mg g−1 for RBBR, respectively). Furthermore, the LDH film exhibits excellent sorption−regeneration performances as compared to the powder sample, which facilitates its repeatable and cyclic usage over a long period. Because of the low-cost preparation, high sorption capacity, convenient manipulation, as well as easy regeneration of the LDH film, it is expected that this film can be potentially used as a structured adsorbent in the field of water treatment

Synergistic Catalysis at the Ni/ZrO_2–<i>x</i> Interface toward Low-Temperature CO₂ Methanation

The CO2 methanation reaction, which achieves the carbon cycle and gains value-added chemicals, has attracted much attention, but the design and exploitation of highly active catalysts remain a big challenge. Herein, zirconium dioxide-supported Ni catalysts toward low-temperature CO2 methanation are obtained via structural topological transformation of NiZrAl-layered double hydroxide (LDH) precursors, which have the feature of an interfacial structure (Ni–O–Zr3+–Vö) between Ni nanoparticles and ZrO2–x support (0 x 2–x-S2) exhibits exceptional CO2 conversion (∼72%) at a temperature as low as 230 °C with a ∼100% selectivity to CH4, without obvious catalyst deactivation within a 110 h reaction at a high gas hourly space velocity of 30,000 mL·g–1·h–1. Markedly, the space–time yield of CH4 reaches up to ∼0.17 molCH4·gcat–1·h–1, which is superior to previously reported Ni catalysts evaluated under similar reaction conditions. Both in situ/operando investigations (diffuse reflectance infrared Fourier transform spectroscopy and X-ray absorption fine structure) and catalytic evaluations substantiate the interfacial synergistic catalysis at the Ni/ZrO2–x interface: the Zr3+–Vö facilitates the activation adsorption of CO2, while the H2 molecule experiences dissociation at the metallic Ni sites. This work demonstrates that the metal–support interface effect plays a key role in improving the catalytic behavior toward CO2 methanation, which can be extended to other high-performance heterogeneous catalysts toward structure-sensitive systems

Novel Oxygen-Dependent Degradable Immunotoxin Regulated by the Ubiquitin–Proteasome System Reduces Nonspecific Cytotoxicity

The use of bacterial toxins as antitumor agents has received considerable attention. Immunotoxins based on antigen recognition of single-chain antibodies have been widely explored for cancer therapy. Despite their impressive killing effect on tumor cells, immunotoxins still display unspecific toxicity with undesired side effects. High levels of hypoxia-inducible factor 1α (HIF-1α) are well-known indicators of hypoxia in cancer cells. In this study, different linkers were employed to fuse the immunotoxin DAB389-4D5 scFv (DS) with the oxygen-dependent degradation domain (ODDD) of HIF-1α, a domain selectively facilitating the accumulation of HIF-1α under hypoxia, to construct the oxygen-dependent degradable immunotoxin DS-ODDD (DSO). The engineered fusion protein DSO-2 containing a linker (G4S)3 possesses the best killing effect on cancer cells under hypoxia and displayed considerably reduced nonspecific toxicity to normal cells under normoxic conditions. Flow cytometry, immunofluorescence, and immunoblot analyses demonstrated that DSO-2 was degraded via the ubiquitin–proteasome pathway regulated by the oxygen-sensitive mechanism. Western blot analysis indicated that the degradation of DSO-2 significantly decreased the activation of apoptosis-related molecules in normal cells. The engineered immunotoxin with oxygen-sensing properties developed herein is a potential therapeutic agent for cancer treatment

Heteroatom Polymer-Derived 3D High-Surface-Area and Mesoporous Graphene Sheet-Like Carbon for Supercapacitors

Current supercapacitors suffer from low energy density mainly due to the high degree of microporosity and insufficient hydrophilicity of their carbon electrodes. Development of a supercapacitor capable of simultaneously storing as much energy as a battery, along with providing sufficient power and long cycle stability would be valued for energy storage applications and innovations. Differing from commonly studied reduced graphene oxides, in this work we identified an inexpensive heteroatom polymer (polyaniline-PANI) as a carbon/nitrogen precursor, and applied a controlled thermal treatment at elevated temperature to convert PANI into 3D high-surface-area graphene-sheet-like carbon materials. During the carbonization process, various transition metals including Fe, Co, and Ni were added, which play critical roles in both catalyzing the graphitization and serving as pore forming agents. Factors including post-treatments, heating temperatures, and types of metal were found crucial for achieving enhanced capacitance performance on resulting carbon materials. Using FeCl₃ as precursor along with optimal heating temperature 1000 °C and mixed acid treatment (HCl+HNO₃), the highest Brunauer–Emmett–Teller (BET) surface area of 1645 m²g^–1 was achieved on the mesopore dominant graphene-sheet-like carbon materials. The unique morphologies featured with high-surface areas, dominant mesopores, proper nitrogen doping, and 3D graphene-like structures correspond to remarkably enhanced electrochemical specific capacitance up to 478 Fg^–1 in 1.0 M KOH at a scan rate of 5 mV s^–1. Furthermore, in a real two-electrode system of a symmetric supercapacitor, a specific capacitance of 235 Fg^–1 using Nafion binder is obtained under a current density of 1 Ag^–1 by galvanostatic charge–discharge tests in 6.0 M KOH. Long-term cycle stability up to 5000 cycles by using PVDF binder in electrode was systematically evaluated as a function of types of metals and current densities

DataSheet1_PD-L1 aptamer-functionalized degradable hafnium oxide nanoparticles for near infrared-II diagnostic imaging and radiosensitization.DOCX

Immune checkpoint blockade is now recognized as a paradigm-shifting cancer therapeutic strategy, whereas there remains difficulty in accurately predicting immunotherapy efficacy by PD-L1 expression. In addition, radiotherapy for cancer patients faces the problem of insufficient dose of radiotherapy at the tumor site while which have been not tolerated by normal tissues. In this study, we created PD-L1 aptamer-anchored spherical nucleic acids (SNAs) with a shell made of PD-L1 aptamer and indocyanine green (ICG) embedded in a mesoporous hafnium oxide nanoparticle core (Hf@ICG-Apt). Upon low pH irradiation in the tumor sites, the nano-system enabled the release of ICG in the high PD-L1 expression tumor to develop a high tumor-to-background ratio of 7.97 ± 0.76 and enhanced the ICG tumor retention to more than 48 h. Moreover, Hf@ICG-Apt improved radiation therapy (RT) when combined with radiation. Notably, Hf@ICG-Apt showed scarcely any systemic toxicity in vivo. Overall, this research offered a novel approach for applying reliable monitoring of PD-L1 expression and localization and robust RT sensitization against cancer with good biosafety.</p

Image_5_SmMYB113 Is a Key Transcription Factor Responsible for Compositional Variation of Anthocyanin and Color Diversity Among Eggplant Peels.TIF

To understand the color formation mechanism in eggplant (Solanum melongena L.) peel, a metabolomic analysis was performed in six cultivars with different peel colors. A total of 167 flavonoids, including 16 anthocyanins, were identified based on a UPLC-MS/MS approach. Further analysis revealed that the delphinidins/flavonoids ratio was consistent with the purple coloration of eggplant peels, and SmF3′5′H expression level was consistent with the delphinidin 3-O-glucoside and delphinidin 3-O-rutinoside contents, the main anthocyanins in the purple-peels eggplant cultivars identified in this study. SmMYB113 overexpression promoted anthocyanins accumulation in eggplant peels and pulps. Metabolomic analysis revealed that delphinidins were still the main anthocyanins class in the peels and pulps of SmMYB113-OE4, but most anthocyanins were glycosylated at the 5-position of the B-ring. Our results provide new insights into the anthocyanin composition of eggplant peels and demonstrate the importance of SmMYB113 in stimulating anthocyanin biosynthesis in eggplant fruits.</p

SI_revised – Supplemental material for Synthesis of novel chiral fluorescent sensors and their application in enantioselective discrimination of chiral carboxylic acids

Supplemental material, SI_revised for Synthesis of novel chiral fluorescent sensors and their application in enantioselective discrimination of chiral carboxylic acids by Qiuhan Yu, Weiwen Lu, Zhiqiang Ding, Min Wei and Zhenya Dai in Journal of Chemical Research</p