The introduction of oxygen vacancies (Ov) has been regarded as an effective method to enhance the catalytic performance of photoanodes in oxygen evolution reaction (OER). However, their stability ...under highly oxidizing environment is questionable but was rarely studied. Herein, NiFe‐metal–organic framework (NiFe‐MOFs) was conformally coated on oxygen‐vacancy‐rich BiVO4 (Ov‐BiVO4) as the protective layer and cocatalyst, forming a core–shell structure with caffeic acid as bridging agent. The as‐synthesized Ov‐BiVO4@NiFe‐MOFs exhibits enhanced stability and a remarkable photocurrent density of 5.3±0.15 mA cm−2 at 1.23 V (vs. RHE). The reduced coordination number of Ni(Fe)‐O and elevated valence state of Ni(Fe) in NiFe‐MOFs layer greatly bolster OER, and the shifting of oxygen evolution sites from Ov‐BiVO4 to NiFe‐MOFs promotes Ov stabilization. Ovs can be effectively preserved by the coating of a thin NiFe‐MOFs layer, leading to a photoanode of enhanced photocurrent and stability.
A core–shell Ov‐BiVO4@NiFe‐MOFs photoanode was constructed via a coordination‐assisted self‐assembly method. A NiFe‐MOFs thin layer acts as protective layer and cocatalyst to shift active sites from oxygen vacancies to NiFe‐MOFs, leading to improved stability and activity for OER. This molecular‐based approach tailors the coordination and electronic structure of active sites and provides mechanistic insights for rational design of photocatalysts.
► Identification of technically and economically feasible methods to modify natural bentonite for removing diazo dye in wastewater. ► Determination of the optimal adsorption performance. ► ...Characterisation of adsorption isotherm and kinetic models of the physio-chemical modified bentonite. ► Description of adsorption diffusion mechanisms and model of the dye–bentonite reaction.
Low adsorption capacity of natural clay minerals is a key technical and economical issue which limits their industrial application as low cost absorbents for removal of hazardous contaminants from wastewater. Herein, natural bentonite was modified by thermal activation (TA), acid activation (AA) and combined acid and thermal activation (ATA). In this study, we studied how the key operational parameters: contact time, dye concentration, bentonite dosage, pH and temperature could affect the adsorption performance for the removal of Congo red (CR). The thermodynamic parameters revealed that adsorption reaction using the modified clays is spontaneous and exothermic. The experimental data were analyzed by Langmuir and Freundlich isotherm, Pseudo-kinetic and particle diffusion models. The results revealed that Freundlich isotherm provided a better fit to the experimental data. The adsorption kinetics followed both the pseudo first and second-order rate equations, while the second order giving a better fit. The adsorption process also showed a intra-particle diffusion mechanism. The ATA bentonite demonstrated the highest adsorption capacity by removing over 95% of CR and its adsorption fitted best to all models.
Photoelectrochemical (PEC) water splitting into hydrogen and oxygen is a promising solution for the conversion and storage of solar energy. Because sluggish water oxidation is the bottleneck of water ...splitting, the design and preparation of an efficient photoanode is intensively investigated. Currently, all known photoanode materials suffer from at least one of the following drawbacks: ① low carriers separation efficiency; ② sluggish surface water oxidation reaction; ③ poor long‐term stability; ④ insufficient water adsorption and gas desorption. Core–shell configurations can endow a photoanode with improved activity and stability by coating an overlayer that plays energetic, catalytic, and/or protective roles. The construction strategy has an important effect on the activity of a core–shell photoanode. Nonetheless, the mechanism for the improvement of performance is still ambiguous and is worthy of a closer examination. In this review, the successes and challenges of core–shell photoanodes for water oxidation, focusing on synthesis strategies as well as functionalities (facilitating carrier separation, surface reaction promotion, corrosion prevention, and bubble detachment) are explored. Finally, the perspectives of this class of materials in terms of new opportunities and efforts are discussed.
Core–shell configurations, constructed via photo/electrodeposition, atomic layer deposition, chemical vapor deposition, ligand‐assisted strategy or ion exchange strategy, endow photoanodes with improved activity and stability by optimizing and facilitating carrier separation, surface reaction promotion, corrosion prevention, and bubble detachment process during photoelectrochemical water oxidation.
Soil gross nitrification (GN) is a critical process in the global nitrogen (N) cycle that results in the formation of nitrate through microbial oxidation of ammonium or organic N, and can both ...increase N availability to plants and nitrous oxide emissions. Soil GN is thought to be mainly controlled by soil characteristics and the climate, but a comprehensive analysis taking into account the climate, soil characteristics, including microbial characteristics, and their interactions to better understand the direct and indirect controlling factors of GN rates globally is lacking. Using a global meta‐analysis based on 901 observations from 330 15N‐labeled studies, we show that GN differs significantly among ecosystem types, with the highest rates found in croplands, in association with higher pH which stimulates nitrifying bacteria activities. Autotrophic and heterotrophic nitrifications contribute 63% and 37%, respectively, to global GN. Soil GN increases significantly with soil total N, microbial biomass, and soil pH, but decreases significantly with soil carbon (C) to N ratio (C:N). Structural equation modeling suggested that GN is mainly controlled by C:N and soil total N. Microbial biomass and pH are also important factors controlling GN and their effects are similar. Precipitation and temperature affect GN by altering C:N and/or soil total N. Soil total N and temperature drive heterotrophic nitrification, whereas C:N and pH drive autotrophic nitrification. Moreover, GN is positively related to nitrous oxide and carbon dioxide emissions. This synthesis suggests that changes in soil C:N, soil total N, microbial population size, and/or soil pH due to anthropogenic activities may influence GN, which will affect nitrate accumulation and gaseous emissions of soils under global climate and land‐use changes.
Using a global meta‐analysis based on 901 observations from 330 15N‐labelled studies, we show that gross nitrification rate (GN) is mainly controlled by soil carbon‐to‐nitrogen stoichiometry and soil total nitrogen. Soil microbial biomass and pH are also important factors controlling GN. Mean annual precipitation and mean annual temperature affect GN by altering soil carbon‐to‐nitrogen stoichiometry and/or soil total nitrogen. GN is positively related to nitrous oxide and carbon dioxide emissions. We suggest that changes in soil substrate quantity and quality due to anthropogenic activities may influence GN, which will affect nitrate accumulation and gaseous emissions of soils under global climate changes.
This paper considers the parameter identification problems of controlled autoregressive systems using observation information. According to the hierarchical identification principle, we decompose the ...controlled autoregressive system into two subsystems by introducing two fictitious output variables. Then a two-stage gradient-based iterative algorithm is proposed by means of the iterative technique. In order to improve the performance of the tracking the time-varying parameters, we derive a two-stage multi-innovation gradient-based iterative algorithm based on the multi-innovation identification theory. Finally, an example is provided to illustrate the effectiveness of the proposed algorithms.
Intensive aquaculture has increased the severity and frequency of fish diseases. Given the functional importance of gut microbiota in various facets of host physiology, modulation of this microbiota ...is a feasible strategy to mitigate emerging diseases in aquaculture. To achieve this, a fundamental understanding of the interplay among fish health, microbiota, and invading pathogens is required. This mini-review focuses on current knowledge regarding the associations between fish diseases, dysbiosis of gut microbiota, and immune responses. Furthermore, updated research on fish disease from an ecological perspective is discussed, including colonization resistance imposed by commensals and strategies used by pathogens to overcome resistance. We also propose several directions for future research, such as exploration of the causal links between fish diseases and specific taxa, and identification of universal gut microbial biomarkers for rapid disease diagnosis.
The extensively developed ene‐type enantioselective cycloisomerization of classical 1,n‐enynes provides an efficient approach to chiral cyclic 1,4‐dienes. In contrast, the catalytic asymmetric ...heteroarenyne (heteroarene–alkyne) cycloisomerization involving the dearomative transformation of endocyclic aromatic C=C bonds remains unknown. Herein, we communicate a PdH‐catalyzed enantioselective heteroarenyne cycloisomerization reaction of alkyne‐tethered indole substrates (formal 1,5‐ and 1,6‐enynes). Based on this strategy, a variety of structurally diverse chiral spiro and fused indoline derivatives bearing quaternary stereocenters and exocyclic C=C bonds are afforded in moderate to excellent yields and excellent enantioselectivities (up to 98 % ee). The classical ene‐type enantioselective 1,5‐enyne cycloisomerization of N‐vinylpropiolamides is also developed to afford chiral 2‐pyrrolones in good to excellent ee values.
A palladium‐catalyzed enantioselective ene‐type cycloisomerization of heteroarenynes has been developed with alkyne‐tethered indoles as substrates. The reaction provides an efficient avenue for the synthesis of structurally diverse indolines bearing quaternary stereocenters in moderate to excellent yields and excellent enantioselectivities (up to 98 % ee).
NANOBODY® (a registered trademark of Ablynx N.V) molecules (Nbs), also referred to as single domain-based VHHs, are antibody fragments derived from heavy-chain only IgG antibodies found in the
...family. Due to their small size, simple structure, high antigen binding affinity, and remarkable stability in extreme conditions, nanobodies possess the potential to overcome several of the limitations of conventional monoclonal antibodies. For many years, nanobodies have been of great interest in a wide variety of research fields, particularly in the diagnosis and treatment of diseases. This culminated in the approval of the world's first nanobody based drug (Caplacizumab) in 2018 with others following soon thereafter. This review will provide an overview, with examples, of (i) the structure and advantages of nanobodies compared to conventional monoclonal antibodies, (ii) methods used to generate and produce antigen-specific nanobodies, (iii) applications for diagnostics, and (iv) ongoing clinical trials for nanobody therapeutics as well as promising candidates for clinical development.
Microbial nitrogen (N) immobilization, which typically results in soil N retention but based on the balance of gross N immobilization over gross N production, affects the fate of the anthropogenic ...reactive N. However, global patterns and drivers of soil gross immobilization of ammonium (INH4) and nitrate (INO3) are still only tentatively known. Here, we provide a comprehensive analysis considering gross N production rates, soil properties, and climate and their interactions for a deeper understanding of the patterns and drivers of INH4 and INO3. By compiling and analyzing 1966 observations from 274 15N‐labelled studies, we found a global average of INH4 and INO3 of 7.41 ± 0.72 and 2.03 ± 0.30 mg N kg−1 day−1 with a ratio of INO3 to INH4 (INO3:INH4) of 0.79 ± 0.11. Soil INH4 and INO3 increased with increasing soil gross N mineralization (GNM) and nitrification (GN), microbial biomass, organic carbon, and total N and decreasing soil bulk density. Our analysis revealed that GNM and GN were the main stimulators for INH4 and INO3, respectively. The structural equation modeling showed that higher soil microbial biomass, total N, pH, and precipitation stimulate INH4 and INO3 through enhancing GNM and GN. However, higher temperature and soil bulk density suppress INH4 and INO3 by reducing microbial biomass and total N. Soil INH4 varied with terrestrial ecosystems, being greater in grasslands and forests, which have higher rates of GNM, than in croplands. The highest INO3:INH4 was observed in croplands, which had higher rates of GN. The global average of GN to INH4 was 2.86 ± 0.31, manifesting a high potential risk of N loss. We highlight that anthropogenic activities that influence soil properties and gross N production rates likely interact with future climate changes and land uses to affect soil N immobilization and, eventually, the fate of the anthropogenic reactive N.
By compiling and analyzing 1966 observations from 274 studies, we found that soil gross nitrogen production rates drive soil gross immobilization of ammonium (INH4) and nitrate (INO3). Higher soil microbial biomass, total nitrogen, pH, and precipitation stimulate INH4 and INO3 through enhancing gross nitrogen production rates. Higher temperature and soil bulk density suppress INH4 and INO3 by reducing microbial biomass and total nitrogen. We highlight that anthropogenic activities that influence soil properties and gross nitrogen production likely interact with future climate changes and land uses to affect soil nitrogen immobilization and, eventually, the fate of the anthropogenic reactive nitrogen.
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