Multiscale nanoengineering fabrication of air electrode catalysts in rechargeable Zn-air batteries.

The development of cost-effective, high-activity and stable catalysts to accelerate the sluggish kinetics of cathodic oxygen reduction/evolution reactions (ORR/OER) plays a critical part in commercialization application of rechargeable Zn-air batteries (RZABs). Herein, a multiscale nanoengineering strategy is developed to simultaneously stabilize Co-doped Fe nanoparticles originated from metal-organic framework-derived approach and atomic Fe/Co sites derived from metal nanoparticle-atomized way on N-doped hierarchically tubular porous carbon substrate. Thereinto, metal nanoparticles and single atoms are respectively used to expedite the OER and ORR. Consequently, the final material is acted as an oxygen electrode catalyst, displaying 0.684 V of OER/ORR potential gap, 260 mW cm-2 of peak power density for liquid-state RZAB, 110 mW cm-2 of peak power density for solid-state RZAB, and 1000 charge-discharge cycles without decay, which confirms great potential for energy storage and conversion applications.

Universal Sublimation Strategy to Stabilize Single-Metal Sites on Flexible Single-Wall Carbon-Nanotube Films with Strain-Enhanced Activities for Zinc-Air Batteries and Water Splitting.

Single-metal-site catalysts have recently aroused extensive research in electrochemical energy fields such as zinc-air batteries and water splitting, but their preparation is still a huge challenge, especially in flexible catalyst films. Herein, we propose a sublimation strategy in which metal phthalocyanine molecules with defined isolated metal-N4 sites are gasified by sublimation and then deposited on flexible single-wall carbon nanotube (SWCNT) films by means of π-π coupling interactions. Specifically, iron phthalocyanine anchored on the SWCNT film prepared was directly used to boost the cathodic oxygen reduction reaction of the zinc-air battery, showing a high peak power density of 247 mW cm-2. Nickel phthalocyanine and cobalt phthalocyanine were, respectively, stabilized on SWCNT films as the anodic and cathodic electrocatalysts for water splitting, showing a low potential of 1.655 V at 10 mA cm-2. In situ Raman spectra and theoretical studies demonstrate that highly efficient activities originate from strain-induced metal phthalocyanine on SWCNTs. This work provides a universal preparation method for single-metal-site catalysts and innovative insights for electrocatalytic mechanisms.

Adequate nutrient intake mitigate the toxic effects of bromate on the rotifer Brachionus calyciflorus.

Bromate is receiving increased attention as a typical disinfection by-product in aquatic environments, but bromate toxicity tests on invertebrate such as Brachionus calyciflorus rotifer are inadequate. In the present study, the long-term toxicity tests on B. calyciflorus were performed during 21 days under the exposure of different bromate concentrations and two algal density conditions. Furthermore, we evaluated the feeding behaviors of the rotifers under the impact of bromate. The maximum population density of rotifers was significantly reduced at 100 and 200 mg/L bromate exposure at the two algal density conditions. However, we observed that the maximum population density and population growth rate of rotifers were higher at 3.0 × 106 cells/mL algal density than those at 1.0 × 106 cells/mL under the same conditions of bromate exposure. These results suggest that higher food density may have alleviated the negative effects of bromate on rotifers. Meanwhile, the ingestion rate at an algal density of 3.0 × 106 cells/mL was higher than that at 1.0 × 106 cells/mL. The present study provides a basic reference to comprehensively evaluate the toxic effects of bromate on aquatic organisms.

Effect of Phosphorus Modulation in Iron Single-Atom Catalysts for Peroxidase Mimicking.

Fe-N-C single-atom catalysts (SACs) exhibit excellent peroxidase (POD)-like catalytic activity, owing to their well-defined isolated iron active sites on the carbon substrate, which effectively mimic the structure of natural peroxidase's active center. To further meet the requirements of diverse biosensing applications, SAC POD-like activity still needs to be continuously enhanced. Herein, a phosphorus (P) heteroatom is introduced to boost the POD-like activity of Fe-N-C SACs. A 1D carbon nanowire (FeNCP/NW) catalyst with enriched Fe-N4 active sites is designed and synthesized, and P atoms are doped in the carbon matrix to affect the Fe center through long-range interaction. The experimental results show that the P-doping process can boost the POD-like activity more than the non-P-doped one, with excellent selectivity and stability. The mechanism analysis results show that the introduction of P into SAC can greatly enhance POD-like activity initially, but its effect becomes insignificant with increasing amount of P. As a proof of concept, FeNCP/NW is employed in an enzyme cascade platform for highly sensitive colorimetric detection of the neurotransmitter acetylcholine.

Prussian-Blue-Analogue-Derived Ultrathin Co2P-Fe2P Nanosheets for Universal-pH Overall Water Splitting.

The great interest in large-scale electrochemical water splitting toward clean hydrogen has spurred large numbers of studies on developing cost-efficient and high-performance bifunctional electrocatalysts. Here, a Prussian-blue-analogue-derived method is proposed to prepare honeycomb-like ultrathin and heterogeneous Co2P-Fe2P nanosheets on nickel foam, showing low overpotentials of 0.080, 0.088, and 0.109 V for the hydrogen evolution reaction (HER) at 10 mA cm-2 as well as 0.290, 0.370, and 0.730 V for the oxygen evolution reaction (OER) at 50 mA cm-2 in alkaline, acidic, and neutral electrolytes, respectively. When directly applied for universal-pH water electrolysis, excellent performances are achieved especially at ultralow voltages of 1.45 V at 10 mA cm-2, 1.66 V at 100 mA cm-2, and 1.79 V at 500 mA cm-2 under alkaline conditions. In situ Raman spectroscopy measurements demonstrate that the excellent HER performance can be attributed to heterogeneous Co2P-Fe2P while the ultrahigh alkaline OER performance originates from reconstruction-induced oxyhydroxides.

Fads2b Plays a Dominant Role in ∆6/∆5 Desaturation Activities Compared with Fads2a in Common Carp (Cyprinus carpio).

Highly unsaturated fatty acids (HUFAs) are essential for mammalian health, development and growth. However, most mammals, including humans, are incapable of synthesizing n-6 and n-3 HUFAs. Fish can convert C18 unsaturated fatty acids into n-6 and n-3 HUFAs via fatty acid desaturase (Fads), in which Fads2 is a key enzyme in HUFA biosynthesis. The allo-tetraploid common carp theoretically encode two duplicated fads2 genes. The expression patterns and desaturase functions of these two homologous genes are still unknown. In this study, the full length of the fads2a and fads2b were identified in common carp (Cyprinus carpio). Expression analyses indicate that both genes were mainly expressed in the liver and the expression of fads2b is higher than fads2a at different developmental stages in carp embryos. Heterogenous expression and 3D docking analyses suggested that Fads2b demonstrated stronger ∆6 and ∆5 desaturase activities than Fads2a. The core promotor regions of fads2a and fads2b were characterized and found to have different potential transcriptional binding sites. These results revealed the same desaturase functions, but different activities of two homologues of fasd2 genes in common carp. The data showed that fads2b played a more important role in HUFA synthesis through both expression and functional analyses.

Efficacy and safety comparison between axillary lymph node dissection with no axillary surgery in patients with sentinel node-positive breast cancer: a systematic review and meta-analysis.

BACKGROUND: This systematic review and meta-analysis aimed to study the evidence on the efficacy and safety of omitting axillary lymph node dissection (ALND) for patients with clinically node-negative but sentinel lymph node (SLN)-positive breast cancer using all the available evidence. METHODS: The Embase, Medline, and Cochrane Library databases were searched through February 25, 2023. Original trials that compared only the sentinel lymph node biopsy (SLNB) with ALND as the control group for patients with clinically node-negative but SLN-positive breast cancer were included. The primary outcomes were axillary recurrence rate, total recurrence rate, disease-free survival (DFS), and overall survival (OS). Meta-analyses were performed to compare the odds ratio (OR) in rates and the hazard ratios (HR) in time-to-event outcomes between both interventions. Based on different study designs, tools in the revised Cochrane risk of bias tool were used for randomized trials and the risk of bias in nonrandomized studies of interventions to assess the risk of bias for each included article. Funnel plots and Egger's test were used for the publication's bias assessment. RESULTS: In total, 30 reports from 26 studies were included in the systematic review (9 reports of RCTs, 21 reports of retrospective cohort studies). According to our analysis, omitting ALND in patients with clinically node-negative but SLN-positive breast cancer had a similar axillary recurrence rate (OR = 0.95, 95% confidence interval (CI): 0.76-1.20), DFS (HR = 1.02, 95% CI: 0.89-1.16), and OS (HR = 0.97, 95% CI: 0.92-1.03), but caused a significantly lower incidence of adverse events and benefited in locoregional recurrence rate (OR = 0.76, 95% CI: 0.59-0.97) compared with ALND. CONCLUSION: For patients with clinically node-negative but SLN-positive breast cancer (no matter the number of the positive SLN), this review showed that SLNB alone had a similar axillary recurrence rate, DFS, and OS, but caused a significantly lower incidence of adverse events and showed a benefit for the locoregional recurrence compared with ALND. An OS benefit was found in the Macro subset that used SLNB alone versus complete ALND. Therefore, omitting ALND is feasible in this setting. TRIAL REGISTRATION: CRD 42023397963.

Single-Atom Ce-N4-C-(OH)2 Nanozyme-Catalyzed Cascade Reaction to Alleviate Hyperglycemia.

The enzyme-mimicking catalytic activity of single-atom nanozymes has been widely used in tumor treatment. However, research on alleviating metabolic diseases, such as hyperglycemia, has not been reported. Herein, we found that the single-atom Ce-N4-C-(OH)2 (SACe-N4-C-(OH)2) nanozyme promoted glucose absorption in lysosomes, resulting in increased reactive oxygen species production in HepG2 cells. Furthermore, the SACe-N4-C-(OH)2 nanozyme initiated a cascade reaction involving superoxide dismutase-, oxidase-, catalase-, and peroxidase-like activity to overcome the limitations associated with the substrate and produce •OH, thus improving glucose intolerance and insulin resistance by increasing the phosphorylation of protein kinase B and glycogen synthase kinase 3ß, and the expression of glycogen synthase, promoting glycogen synthesis to improve glucose intolerance and insulin resistance in high-fat diet-induced hyperglycemic mice. Altogether, these results demonstrated that the novel nanozyme SACe-N4-C-(OH)2 alleviated the effects of hyperglycemia without evident toxicity, demonstrating its excellent clinical application potential.

Effect of Several Naja atra Antivenom Injection Methods on the Rabbit Model of Naja naja atra Bite Poisoning.

Snakebite is a global public health concern, which often occurs in tropical and subtropical underdeveloped areas, but it is often neglected. In the southern China, Naja naja atra (Chinese cobra) is a common venomous snake that causes swelling and necrosis of local tissues, even amputation and death. Currently, the main therapy is the administration of Naja atra antivenom, which greatly reduces mortality. However, the antivenom is not particularly effective in the improvement of local tissue necrosis. Clinically, antivenom is mainly administered intravenously. We speculated that the method of injection influences the efficacy of antivenom. In this study, the rabbit model was used to explore the effects of different antivenom injection methods on systemic and local poisoning symptoms. If topical injection of antivenom contributes to ameliorate tissue necrosis, then we need to reconsider the use of Naja atra antivenom.

Development of sandwich ELISA and lateral flow assay for the detection of Bungarus multicinctus venom.

Snakebite envenoming adversely affects human health and life worldwide. Presently, no suitable diagnostic tools for snakebite envenoming are available in China. Therefore, we sought to develop reliable diagnostic tests for snakebite management. We conducted affinity purification experiments to prepare species-specific antivenom antibody (SSAb). In brief, affinity chromatography with an antibody purification column (Protein A) was conducted to purify immunoglobulin G from Bungarus multicinctus (BM) venom hyperimmunized rabbit serum. The cross-reactive antibodies were removed from commercial BM antivenin by immune adsorption on the affinity chromatography columns of the other three venoms, Bungarus Fasciatus (FS), Naja atra (NA), and O. hannah (OH), generating SSAb. The results of western blot analysis and enzyme-linked immunosorbent assay (ELISA) showed the high specificity of the prepared SSAb. The obtained antibodies were then applied to ELISA and lateral flow assay (LFA) to detect BM venom. The resulting ELISA and LFA could specifically and rapidly detect BM venom in various samples with the limits of quantification as 0.1 and 1 ng/ml, respectively. This method could effectively detect snake venom in experimentally envenomed rats (simulating human envenomation), which could distinguish positive and negative samples within 10-15 min. This method also showed promise in serving as a highly useful tool for a rapid clinical distinguishing of BM bites and rational use of antivenom in emergency centers. The study also revealed cross-reactivity between BM and heterogenous venoms, suggesting that they shared common epitopes, which is of great significance for developing detection methods for venoms of the snakes belonging to the same family.

[Effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/ß-catenin/PPARγ pathway in arrhythmic rats].

This paper aimed to investigate the effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/ß-catenin/peroxisome proliferator-activated receptor γ(PPARγ) pathway in arrhythmic rats. SD rats were randomly divided into a control group, a model group, a low-dose(20 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a medium-dose(40 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a high-dose(80 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a propranolol hydrochloride(2 mg·kg~(-1)) group, with 12 rats in each group. Except the control group, rats in other groups were prepared as models of arrhythmia by sublingual injection of 1 mL·kg~(-1) of 0.002% aconitine. After grouping and intervention with drugs, the arrhythmia, myocardial cells apoptosis, myocardial tissue glutathione peroxidase(GSH-Px), catalase(CAT), malondialdehyde(MDA), serum interleukin-6(IL-6), prostaglandin E2(PGE2) levels, myocardial tissue apoptosis, and Wnt/ß-catenin/PPARγ pathway-related protein expression of rats in each group were measured. As compared with the control group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA levels in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and ß-catenin protein expression levels increased significantly in the model group, whereas the GSH-Px and CAT levels, and Bcl-2 and PPARγ protein expression levels in myocardial tissues reduced significantly. As compared with the model group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA leve in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and ß-catenin protein expression levels reduced in the drug intervention groups, whereas the GSH-Px and CAT levels and Bcl-2 and PPARγ protein expression levels in myocardial tissues increased. The groups of total flavonoids of buckwheat flower and leaf were in a dose-dependent manner. There was no significant difference in the levels of each index in rats between the propranolol hydrochloride group and the high-dose group of total flavonoids of buckwheat flower and leaf. The total flavonoids of buckwheat flower and leaf inhibit the activation of Wnt/ß-catenin pathway, up-regulate the expression of PPARγ, reduce oxidative stress and inflammatory damage in myocardial tissues of arrhythmic rats, reduce myocardial cell apoptosis, and improve the symptoms of arrhythmia in rats.

Dominant Elongase Activity of Elovl5a but Higher Expression of Elovl5b in Common Carp (Cyprinus carpio).

Most diploid freshwater and marine fish encode one elovl5 elongase, having substrate specificity and activities towards C18, C20 and C22 polyunsaturated fatty acids (PUFAs). The allo-tetraploid common carp is hypothesized to encode two duplicated elovl5 genes. How these two elovl5 genes adapt to coordinate the PUFA biosynthesis through elongase function and expression divergence requires elucidation. In this study, we obtained the full-length cDNA sequences of two elovl5 genes in common carp, named as elovl5a and elovl5b. Functional characterization showed that both enzymes had elongase activity towards C18, C20 and C22 PUFAs. Especially, the activities of these two enzymes towards C22 PUFAs ranged from 3.87% to 8.24%, higher than those in most freshwater and marine fish. The Elovl5a had higher elongase activities than Elovl5b towards seven substrates. The spatial-temporal expression showed that both genes co-transcribed in all tissues and development stages. However, the expression levels of elovl5b were significantly higher than those of elovl5a in all examined conditions, suggesting that elovl5b would be the dominantly expressed gene. These two genes had different potential transcriptional binding sites. These results revealed the complicated roles of elovl5 on PUFA synthesis in common carp. The data also increased the knowledge of co-ordination between two homoeologs of the polyploid fish through function and expression divergence.

Engineering Atomic Single Metal-FeN4Cl Sites with Enhanced Oxygen-Reduction Activity for High-Performance Proton Exchange Membrane Fuel Cells.

Fe-N-C single-atomic metal site catalysts (SACs) have garnered tremendous interest in the oxygen reduction reaction (ORR) to substitute Pt-based catalysts in proton exchange membrane fuel cells. Nowadays, efforts have been devoted to modulating the electronic structure of metal single-atomic sites for enhancing the catalytic activities of Fe-N-C SACs, like doping heteroatoms to modulate the electronic structure of the Fe-Nx active center. However, most strategies use uncontrolled long-range interactions with heteroatoms on the Fe-Nx substrate, and thus the effect may not precisely control near-range coordinated interactions. Herein, the chlorine (Cl) is used to adjust the Fe-Nx active center via a near-range coordinated interaction. The synthesized FeN4Cl SAC likely contains the FeN4Cl active sites in the carbon matrix. The additional Fe-Cl coordination improves the instrinsic ORR activity compared with normal FeNx SAC, evidenced by density functional theory calculations, the measured ORR half-wave potential (E1/2, 0.818 V), and excellent membrane electrode assembly performance.

Phosphatase-like activity of single-atom CeNC nanozyme for rapid detection of Al3.

Single-atom nanozymes are a class of nanozymes with attractive enzyme-like activities. They usually mimic oxidoreductases and lack other types of enzyme-like activities. Hence, we verified a single-atom CeNC (SACeNC) nanozyme with an excellent phosphatase-like (PPA-like) activity, which could catalyze the dephosphorylation of inorganic phosphates. Meanwhile, we found that Al3+ could specifically combine with the O atom in its structure to form an Al-O bond, which could inhibit its PPA-like activity. Based on this principle, we have constructed a fast, portable, and efficient fluorescent liquid phase sensor to detect Al3+. The detection time was only 4 min, and the limit of detection (LOD) was 22.89 ng/mL in the linear range of 5-25 µg/mL. This study not only verified that single-atom nanozymes mimic phosphatase activities, but also applied its unique enzyme-like to the field of food safety rapid detection.

Single-atom Ce-N-C nanozyme bioactive paper with a 3D-printed platform for rapid detection of organophosphorus and carbamate pesticide residues.

Rapid detection of pesticide residues based on enzyme mimics has recently attracted much interest. However, most nanozymes have low activity. Herein, a "single-atom Ce-N-C nanozyme" (SACe-N-C nanozyme) was rationally devised and verified to mimic peroxidase (POD-like) with superior activity. Based on its high POD-like activities and cascaded catalytic reactions with acetylcholinesterase (AChE), we constructed a bioactive paper for the detection of pesticide residues, which offered a portable approach to monitor fruits and vegetables within 30 min. More importantly, a 3D printed platform was integrated on the basis of SACe-N-C bioactive paper to achieve on-site portable testing of omethoate, methamidophos, carbofuran, and carbosulfan, showing limits of detection (LODs) of 55.83, 71.51, 81.81, and 74.98 ng/mL, respectively. The recovery rates were 84.09-104.68%. This study provided new insight into the design of novel single-atom nanozymes for cascaded catalytic detection and other rapid detection applications with high efficiency and low cost.

Ionothermal-Transformation Strategy to Synthesize Hierarchically Tubular Porous Single-Iron-Atom Catalysts for High-Performance Zinc-Air Batteries.

Inexpensive carbon-based nitrogen-coordinated iron single-atom catalysts (CN-FeSACs) have been recently demonstrated as the most promising platinum substitutions for boosting the sluggish oxygen electrode performance in fuel cells and metal-air batteries. However, it is still a great challenge to develop economical and effective CN-FeSACs satisfying the needs of high output power. Herein, an ionothermal-transformation strategy is proposed to synthesize hierarchically tubular porous CN-FeSACs with an ultrahigh special surface area of 2500 m2 g-1 to host abundant single-atom iron sites with an attempt to simultaneously boost sluggish oxygen reduction reaction (ORR) kinetics and mass transport. Benefiting from the unique feature, the final obtained material shows an ORR half-wave potential of 0.885 V, higher than that of benchmark Pt/C (0.850 V). When assembled into zinc-air battery, a large peak power density of 208 mW cm-2 is achieved, which is far superior to that of Pt/C (119 mW cm-2). This work provides an economical and feasible strategy to prepare hierarchically porous CN-FeSACs for energy conversion.

α-Selective C(sp3)-H Thio/Selenocyanation of Ketones with Elemental Chalcogen.

A facile method is disclosed for the synthesis of α-thio/selenocyanato ketones through regioselective C-H thio/selenocyanation of ketones. The advantages include the use of easily available starting materials, high efficiency, simple operation, and easy scale-up. Control experiments provide evidence that the reaction proceeded via a radical way, while kinetic isotope effect experiments reveal that the cleavage of the C-H bond serves as the rate-limiting step.

[Ammonia Nitrogen Removal Performance with Parallel Operation of Conventional and Inverted A2/O Sewage Treatment Processes in Winter].

Ammonia nitrogen (NH4+-N) removal capacities of the A2/O and inverted A2/O processes were analyzed with the same inlet and parallel operation during winter. When the operating water temperature was 14℃, the inverted A2/O process exhibited lower NH4+-N removal from the volumetric load[0.13 kg ·(m3 ·d)-1vs. 0.29 kg ·(m3 ·d)-1] and a lower ammonia oxidation rate (AOR)[0.07 kg ·(kg ·d)-1 vs. 0.11 kg ·(kg ·d)-1] than the A2/O process, whereas the two processes exhibited similar performance at 26℃.The quantitative results for the ammonia oxidizing bacteria (AOB) population were almost the same in the two parallel processes (3.2%±0.24% for the inverted A2/O process and 3.4%±0.31% for the A2/O process). Clone library analysis showed that at low temperatures, the inverted A2/O process had a lower capacity for ammonia nitrogen removal than A2/O process. This is because the particular AOB species[spirillum (Nitrosospira)] facilitated the slower AOR type (K-growth strategy) of nitrosation in the inverted A2/O process, whereas in the A2/O process, the faster AOR type (r-growth strategy) of nitrosation was facilitated by bacterium (Nitrosomonas). At 26℃, the dominant species in the two processes were Nitrosomonas. Through comprehensive analysis of the pollutants during the removal process, we found that although temperature is the leading cause of AOB advantage in species succession, the changes in the inverted A2/O process structure, caused by the aerobic unit, resulted in high COD load and high NH4+-N concentration, which were unfavorable for the growth of AOB. This shows that under conventional sewage conditions, the K-growth strategy is advantageous for the AOB species. Therefore, the structure of the inverted A2/O process for heterotrophic bacteria (phosphorus accumulating bacteria and denitrifying bacteria) indirectly affects the population distribution and succession of autotrophic ammonia-oxidizing bacteria, through COD load and other factors, thereby leading to weakened nitrification capacity at low temperatures.

Serum albumin guided plasmonic nanoassemblies with opposite chiralities.

Chiral assemblies by combining natural biomolecules with plasmonic nanostructures hold great promise for plasmonic enhanced sensing, imaging, and catalytic applications. Herein, we demonstrate that human serum albumin (HSA) and porcine serum albumin (PSA) can guide the chiral assembly of gold nanorods (GNRs) with left-handed chiroptical responses opposite to those by a series of other homologous animal serum albumins (SAs) due to the difference of their surface charge distributions. Under physiological pH conditions, the assembly of HSA or PSA with GNRs yielded left-handed twisted aggregates, while bovine serum albumin (BSA), sheep serum albumin, and equine serum albumin behaved on the contrary. The driving force for the chiral assembly is mainly attributed to electrostatic interaction. The opposite chiroptical signals acquired are correlated with the chiral surface charge distributions of the tertiary structures of SAs. Moreover, the chirality of the assembly induced by both HSA and BSA can be enhanced or reversed by adjusting the pH values. This work provides new insights into the modulation of protein-induced chiral assemblies and promotes their applications.