Multi-analyte fluorescence sensing based on a post-synthetically functionalized two-dimensional Zn-MOF nanosheets featuring excited-state proton transfer process.

Covalent post-synthetic modification of metal-organic frameworks (MOFs) represents an underexplored but promising avenue for allowing the addition of specific fluorescent recognition elements to produce the novel MOF-based sensory materials with multiple-analyte detection capability. Here, an excited-state proton transfer (ESPT) active sensor 2D-Zn-NS-P was designed and constructed by covalent post-synthetic incorporation of the excited-state tautomeric 2-hydroxypyridine moiety into the ultrasonically exfoliated amino-tagged 2D Zn-MOF nanosheets (2D-Zn-NS). The water-mediated ESPT process facilitates the highly accessible active sites incorporated on the surface of 2D-Zn-NS-P to specifically respond to the presence of water in common organic solvents via fluorescence turn-on behavior, and accurate quantification of trace amount of water in acetonitrile, acetone and ethanol was established using the as-synthesized nanosheet sensor with the detection sensitivity (<0.01% v/v) superior to the conventional Karl Fischer titration. Upon exposure to Fe3+ or Cr2O72-, the intense blue emission of the aqueous colloidal dispersion of 2D-Zn-NS-P was selectively quenched even in the coexistence of common inorganic interferents. The prohibition of the water-mediated ESPT process and local emission, induced by the coordination of ESPT fluorophore with Fe3+ or by Cr2O72- competitively absorbs the excitation energy, was proposed to responsible for the fluorescence turn-off sensing of the respective analytes. The present study offers the attractive prospect to develop the ESPT-based fluorescent MOF nanosheets by covalent post-synthetic modification strategy as multi-functional sensors for detection of target analytes.

[Development of Zeolite Loaded Mg-La-Fe Ternary (hydr) oxides for Treatment of Low Concentration Phosphate Wastewater].

A novel Mg-La-Fe ternary (hydr)oxide magnetic zeolite adsorbent (MLFZ) was prepared using the hydrothermal method and employed for effective phosphate removal in this study. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicated that the MLFZ presented an amorphous surface with Mg, Fe, and La dispersed on the surface of the zeolite. The isothermal adsorption and kinetics results showed that the adsorption behavior of the MLFZ was consistent with that of the Langmuir isothermal model and quasi-second-order kinetics model. A relatively fast adsorption of phosphate with a short equilibrium time of 30 min was observed in the kinetics experiment, and the maximum adsorption capacity of the MLFZ was 13.46 mg·g-1 in the equilibrium adsorption isotherm study. The MLFZ showed effective adsorption performance over a wide pH range from 3.0 to 9.0. Moreover, the coexisting ions had an insignificant effect on phosphate adsorption. The MLFZ could easily be recovered using a magnet. After five adsorption-desorption cycles, the phosphate removal efficiency was maintained at approximately 90%. The FTIR, XPS, and Zeta potential analysis confirmed that the adsorption mechanisms were attributed to the surface deposition, electrostatic adsorption, and the inner complex formation by ligand exchange between lanthanum and phosphate. Furthermore, the MLFZ demonstrated high efficiency in scavenging phosphate from a natural pond (phosphate concentration decreased from 0.86 mg·L-1 to 0.013 mg·L-1), indicating that the MLFZ was an ideal material for phosphate management and treatment.

Potential role of nitrite-dependent anaerobic methane oxidation in methane consumption and nitrogen removal in Chinese paddy fields.

Nitrite-dependent anaerobic methane oxidation (n-damo), catalyzed by bacteria closely related to Candidatus Methylomirabilis oxyfera, links the global carbon and nitrogen cycles. Currently, the contribution of n-damo in controlling methane emissions and nitrogen removal, and the key regulatory factors of this process in Chinese paddy fields are poorly known. Here, soil samples from 20 paddy fields located in different climate zones across China were collected to examine the n-damo activity and bacterial communities. The n-damo activity and bacterial abundance varied from 1.05 to 5.97 nmol CH4 g-1 (dry soil) d-1 and 2.59 × 105 to 2.50 × 107 copies g-1 dry soil, respectively. Based on the n-damo activity, it was estimated that approximately 0.91 Tg CH4 and 2.17 Tg N could be consumed annually via n-damo in Chinese paddy soils. The spatial variations in n-damo activity and community structure of n-damo bacteria were significantly (p < 0.05) affected by the soil ammonium content, labile organic carbon content and pH. Furthermore, significant differences in n-damo activity, bacterial abundance and community composition were observed among different climate zones. The n-damo activity was found to be positively correlated with the mean annual air temperature. Taken together, our results demonstrated the potential importance of n-damo in both methane consumption and nitrogen removal in Chinese paddy soils, and this process was regulated by local soil and climatic factors.

Poly(N-phenylglycine)/MoS2 Nanohybrid with Synergistic Solar-Thermal Conversion for Efficient Water Purification and Thermoelectric Power Generation.

Solar interfacial evaporation is an emerging technology in solar energy harvesting developed to remedy the global energy crisis and the lack of freshwater resources. However, developing fully enhanced thermal management to optimize solar-heat utilization efficiency and form remains a great challenge. We created a synergistic photothermal layer from a poly(N-phenylglycine) (PNPG)/MoS2 nanohybrid via electrostatic-induced self-assembly for a broad-spectrum and efficient solar absorption. The PNPG/MoS2 system provided effective synergistic photothermal conversion and good water transmission, enabling rapid solar steam escape. Notably, synergistic coupling of solar evaporation-thermoelectric (TE) power generation was also achieved, providing more efficient exploitation of solar heat. The system demonstrated a solar evaporation rate of up to 1.70 kg m-2 h-1 and achieved a maximum thermoelectric output power with 0.23 W m-2 under one sun. The high-performance PNPG/MoS2 synergistic photothermal system developed in this study offers potential opportunities for coupling solar water purification with thermoelectric power generation to meet the needs of resource-scarce areas.

Cognitive impairment in children with benign childhood epilepsy with centrotemporal spikes and attention deficit hyperactivity disorder: a prospective study. / ä¼´ä¸­å¤®é¢žåŒºæ£˜æ³¢çš„å„¿ç«¥è‰¯æ€§ç™«ç—«å ±æ‚£æ³¨æ„ç¼ºé™·å¤šåŠ¨éšœç¢æ‚£å„¿è®¤çŸ¥åŠŸèƒ½æŸå®³çš„å‰çž»æ€§ç ”ç©¶.

OBJECTIVES: To study the difference in cognitive impairment between the children with benign childhood epilepsy with centrotemporal spikes (BECT) and attention deficit hyperactivity disorder (ADHD) and those with BECT or ADHD alone. METHODS: A prospective study was performed on 80 children with BECT and ADHD, 91 children with BECT, and 70 children with ADHD , who were diagnosed with the diseases for the first time. Seventy children of the same age who underwent physical examination were enrolled as the healthy control group. Event-related potential P300, Wechsler Intelligence Scale for Children, and integrated visual and auditory continuous performance test were used to measure and compare each index between groups. RESULTS: Compared with the healthy control group, the BECT+ADHD group, the BECT group, and the ADHD group had a significantly prolonged P300 latency, a significant reduction in the amplitude of P300, and significant reductions in the scores of verbal comprehension index (VCI), perceptual reasoning index (PRI), working memory index (WMI), processing speed index (PSI), full scale intelligence quotient (FSIQ), auditory response control quotient (ARCQ), visual response control quotient, full response control quotient (FRCQ), auditory attention quotient (AAQ), visual attention quotient, and full attention quotient (P<0.05). Compared with the BECT group, the BECT+ADHD group had a significantly prolonged P300 latency, a significant reduction in the amplitude of P300, and significant reductions in the scores of VCI, PRI, WMI, PSI, FSIQ, and FRCQ (P<0.05). Compared with the ADHD group, the BECT+ADHD group had a significantly prolonged P300 latency, a significant reduction in the amplitude of P300, and significant reductions in the scores of VCI, PRI, FSIQ, ARCQ, FRCQ, and AAQ (P<0.05). CONCLUSIONS: Compared with the children with BECT or ADHD alone, the children with both BECT and ADHD have basically the same fields of cognitive impairment but a higher degree of cognitive impairment in some fields.

Response of nitrite-dependent anaerobic methanotrophs to elevated atmospheric CO2 concentration in paddy fields.

Nitrite-dependent anaerobic methane oxidation (n-damo) catalyzed by Candidatus Methylomirabilis oxyfera (M. oxyfera)-like bacteria is a new pathway for the regulation of methane emissions from paddy fields. Elevated atmospheric CO2 concentrations (e[CO2]) can indirectly affect the structure and function of microbial communities. However, the response of M. oxyfera-like bacteria to e[CO2] is currently unknown. Here, we investigated the effect of e[CO2] (ambient CO2 + 200 ppm) on community composition, abundance, and activity of M. oxyfera-like bacteria at different depths (0-5, 5-10, and 10-20 cm) in paddy fields across multiple rice growth stages (tillering, jointing, and flowering). High-throughput sequencing showed that e[CO2] had no significant effect on the community composition of M. oxyfera-like bacteria. However, quantitative PCR suggested that the 16S rRNA gene abundance of M. oxyfera-like bacteria increased significantly in soil under e[CO2], particularly at the tillering stage. Furthermore, 13CH4 tracer experiments showed potential n-damo activity of 0.31-8.91 nmol CO2 g-1 (dry soil) d-1. E[CO2] significantly stimulated n-damo activity, especially at the jointing and flowering stages. The n-damo activity and abundance of M. oxyfera-like bacteria increased by an average of 90.9% and 50.0%, respectively, under e[CO2]. Correlation analysis showed that the increase in soil dissolved organic carbon content caused by e[CO2] had significant effects on the activity and abundance of M. oxyfera-like bacteria. Overall, this study provides the first evidence for a positive response of M. oxyfera-like bacteria to e[CO2], which may help reduce methane emissions from paddy fields under future climate change conditions.

[Effects of Wheat Straw Hydrochar and Its Modified Product on Rice Yield and Ammonia Volatilization from Paddy Fields].

Hydrochar can mitigate ammonia volatilization when applied in paddy fields due to its acidity and adsorption property. To realize the recycling of agricultural biowaste as well as the control of nutrient loss from paddy fields, a simulation soil-column experiment with wheat straw hydrochar (WHC) and water-washed hydrochar (W-WHC) was conducted to evaluate the performance of rice yield and ammonia volatilization from paddy fields. The results showed that WHC and W-WHC applied in paddy fields both increased the rice yield and the increased effect at low application rate (0.5%) was higher than that at high application rate (1.5%). In comparison with the control treatment (CKU), the rice yields achieved from low application rate treatments for WHC and W-WHC increased by 17.16% and 20.20% respectively. Except for the equal emission rate between W-WHC with low application rate and CKU treatments, hydrochar (WHC, W-WHC) addition reduced the ammonia volatilization from paddy fields when compared with the CKU. Among them, the ammonia volatilization levels from low-application WHC and high-application W-WHC treatments were significantly lower than that from the CKU treatment, reduced by 31.01% and 17.40%, respectively. Based on the analysis of ammonia volatilization during different fertilization stages, the control effect of hydrochar addition on ammonia volatilization was mainly benefited from tillering and panicle fertilizer stages. The change in the nitrogen concentration of surface water at the tillering fertilizer stage and in pH at the panicle fertilizer stage with the addition of hydrochar was the main driving factor for the reduction in ammonia volatilization. The results show that sufficient amounts of hydrochar derived from wheat straw application can increase crop yield while reducing ammonia volatilization from paddy fields. This method provides an effective route for recycling agricultural biowastes.

[Effects of Modified Biowaste-based Hydrochar on Rice Yield and Nitrogen Uptake].

Biochar application on farmlands is an efficient way to realize agricultural/forestry biowaste recycling in parallel with carbon sequestration. Recently, hydrochar produced by hydrothermal carbonization processes has attracted attention due to the advantages over conventional pyrolytic production (i.e., easier production process, higher carbon yield, reduced energy consumption, and lower flue gas emissions). To clarify the effects of hydrochar applied in farmlands on crop production, as well as to realize the recycling of agricultural/forestry biowaste resources, this study evaluated the effects of four types of modified-hydrochar addition on rice yield and nitrogen uptake in two typical soils and the possible influencing factors through soil-column experiments and material characterization. The results showed that sawdust hydrochar and/or straw hydrochar could increase rice yield and nitrogen uptake, as well as reduce N loss, in both treated soils after physical or biological modification, an effect that was independent of the application rate (5‰, 15‰; mass fraction). In comparison to the control, the rice yield and nitrogen uptake of hydrochar-addition treatments increased by 9.2%-20.7% and 7.7%-17.0% respectively. Sawdust hydrochar, with a wider C/N material, was conducive to improving nitrogen uptake in high fertility soils; meanwhile, the nitrogen utilization in low fertility soils was less affected by the type of hydrochar due to the limitations imposed by multiple factors. The results of material characterization showed that the surface of the hydrochar was rich in nutrients; the pore structure of hydrochar after washing or biological modification was greatly improved, the relative content of C was remarkably reduced, and the relative contents of N and O notably increased, which could affect nutrient fixation and supply. Thus, the improved pore structure and increased contents of N and O of modified hydrochars may be the key drivers for the increase in rice yield and nitrogen uptake with hydrochar addition. These results suggest that modified hydrochar is beneficial to realizing agricultural/forestry biowaste recycling and improving crop yield and nitrogen utilization, as well as reducing N loss from farmlands.

[Fabrication of La-MHTC Composites for Phosphate Removal: Adsorption Behavior and Mechanism].

Lanthanum (La)-based materials have shown great potential for phosphate removal owing to the strong affinity between La and phosphate. In this study, magnetic hydrothermal biochar immobilized La(OH)3 (La-MHTC) were prepared and used as phosphate adsorbents. Hydrochar was produced by the hydrothermal carbonization process (220℃, 2 h). Magnetic La-MHTC with different La-to-Fe mass ratios were synthesized by the co-precipitation method. Subsequently, La-MHTC was applied to remove phosphate from wastewater. Results indicate that La-MHTC (with a La-to-Fe mass ratio of 2:1) exhibited excellent magnetic properties for easy recovery and high phosphate adsorption capacity up to 100.25 mg·g-1. Effective phosphate removal was obtained over a wide pH range of 3-10. The absorption isotherm and kinetics were better fitted by the Langmuir model and the pseudo second-order model, respectively, which showed a fast adsorption rate and exhibited superior La utilization efficiency. The La-MHTC has strong selectivity for phosphate in the presence of coexisting ions (Cl-, NO3-, and SO42-). The adsorption-desorption experiment suggested its excellent stability and cyclic utilization. In addition, La-MHTC was applied to treat real domestic wastewater, efficiently reducing the phosphate concentration (from 0.87 mg·L-1 to 0.05 mg·L-1). Electrostatic attraction and inner-sphere complexation between La(OH)3 and P via ligand exchange were the main mechanisms of phosphate adsorption by La-MHTC.

[Effect of Applying Hydrochar for Reduction of Ammonia Volatilization and Mechanisms in Paddy Soil].

Hydrochar, as a product of the hydrothermal carbonization of biomass, has good application prospects for the NH3 volatilization reduction in rice fields due to its rich pore structure and functional surface. In this study, hydrochar was applied as a soil conditioner to paddy soil. A soil column experiment was conducted to investigate the effect of hydrochar on NH3 volatilization throughout the growth period of rice. The experiment was conducted with three treatments:CKU (control without hydrochar); SHC (sawdust hydrochar); and W-SHC (water-washed sawdust hydrochar). The application rate of SHC and W-SHC was 0.5% (w/w). The study investigated the effects of different hydrochars on the pH and concentrations of NH4+-N in floodwater, the flux and accumulation of NH3 volatilization, and the yield-scale cumulative emission of NH3 volatilization. Results show that the SHC treatment significantly reduces cumulative emissions of NH3 volatilization and the yield-scale cumulative emissions of NH3 volatilization (P<0.05), which were 32.42% and 47.61% lower than CKU, respectively. The effect of W-SHC on ammonia volatilization reduction was slightly weaker, as the cumulative emissions of NH3 volatilization and the yield-scale cumulative emissions of NH3 volatilization decreased by 10.14% and 27.71%, respectively, compared with CKU. The NH3 volatilization reduction was possibly related to the disturbance of pH and the decrease in NH4+-N concentrations in the floodwater because of the application of hydrochar. Compared with CKU, both SHC and W-SHC treatments reduced the pH and NH4+-N concentration in the floodwater. The impacts were more obvious in the rice base fertilizer period (BF) and the first supplemental fertilizer period (SF1) than in the second supplemental fertilizer period (SF2). The soil urease activity was significantly inhibited by hydrochar (P<0.05), and the abundance of soil ammonia-oxidizing gene (AOA, AOB) also significantly increased after application of SHC (P<0.05). This resulted in the enhanced efficiency of ammonia-oxidizing, which had an effect on the reduction of the NH4+-N concentrations in the floodwater. This study provides theoretical and experimental data support for the application of hydrochar in agro-environments with regard to ammonia volatilization reduction in paddy fields.

[Expression of VP0 protein of enterovirus 71 in Escherichia coli and generation of the corresponding polyclonal antibodies in guinea pigs].

AIM: To obtain recombinant VP0 protein of enterovirus 71, and generate the corresponding VP0-specific polyclonal antibodies, for molecular detection and characterization of EV71. METHODS: The VP0 gene was amplified by PCR and cloned into vector pET26b to make pET-VP0 for the prokaryotic expression of VP0. The recombinant VP0 protein was expressed in E.coli BL21 harboring pET-VP0, purified from inclusion bodies, renatured, and subsequently used to immunize guinea pigs. The resultant antisera were evaluated for anti-VP0 titer, binding capacity and specificity by ELISA, immunofluorescence staining and Western blot assays. RESULTS: Recombinant protein VP0 was efficiently produced in E.coli. Immunization of guinea pigs with recombinant VP0 elicited high-titer (1:10(6)) VP0-specific antibodies. Western blot analysis showed the resultant anti-VP0 sera reacted with E.coli-expressed VP0 as well as EV71 propagated in Vero cells. Moreover, the antisera positively recognized EV71 infected cells by immunofluorescence staining. CONCLUSION: The recombinant VP0 and the corresponding polyclonal antibodies can be used to identify and characterize EV71, and therefore represent useful agents and tools for the development of new diagnostic methods and vaccines for EV71.