Attenuation of Epileptogenesis and Cognitive Deficits by a Selective and Potent Kv7 Channel Opener in Rodent Models of Seizures.

Targeting neuronal Kv7 channels by pharmacological activation has been proven to be an attractive therapeutic strategy for epilepsy. Here, we show that activation of Kv7 channels by an opener SCR2682 dose-dependently reduces seizure activity and severity in rodent models of epilepsy induced by a GABAa receptor antagonist pentylenetetrazole (PTZ), maximal electroshock, and a glutamate receptor agonist kainic acid (KA). Electroencephalographic recordings of rat cerebral cortex confirm that SCR2682 also decreases epileptiform discharges in KA-induced seizures. Nissl and neuronal nuclei staining further demonstrates that SCR2682 also protects neurons from injury induced by KA. In Morris water maze navigation and Y-maze tests, SCR2682 improves PTZ- and KA-induced cognitive impairment. Taken together, our findings demonstrate that pharmacological activation of Kv7 by novel opener SCR2682 may hold promise for therapy of epilepsy with cognitive impairment. SIGNIFICANCE STATEMENT: A neuronal Kv7 channel opener SCR2682 attenuates epileptogenesis and seizure-induced cognitive impairment in rodent models of seizures, thus possessing a developmental potential for effective therapy of epilepsy with cognitive impairment.

Biomarker of severity in hospitalised patients with COVID-19: a retrospective study.

BACKGROUND: The novel COVID-19 was rapidly spreading and was highly contagious. COVID-19 caused over 6 million deaths worldwide, with high mortality rates, particularly in severe cases. OBJECTIVE: This study aimed to investigate whether serum albumin-neutrophil count to lymphocyte count ratio (NLR) score (ANS) could be used as a prognostic indicator of COVID-19 severity. DESIGN: A retrospective study. PARTICIPANTS: Based on the WHO diagnostic criteria, patients were classified as either non-severe (n=270) or severe (n=100). PRIMARY AND SECONDARY OUTCOME MEASURES: NLR, serum albumin level and ANS. MAIN RESULTS: The NLR of patients with severe disease was significantly higher than that of those with non-severe disease. Serum albumin levels were significantly lower in patients with severe disease than in those with non-severe disease. The cut-off values representing the maximum potential effectiveness of serum albumin and NLR were 33.5 g/L and 8.25, respectively, according to the Youden index. In patients with severe COVID-19, we observed that the serum albumin level, NLR and ANS were independent prognostic indicators of severe COVID-19 using logistic analysis. The relative risk of severe COVID-19 was 7.65 (95% CI 3.72 to 15.75, p<0.05) in the ANS 2 group compared with that in ANS 0. CONCLUSIONS: ANS could be used as a prognostic indicator of COVID-19 severity.

A predictive model to explore risk factors for severe COVID-19.

With the rapid spread of the novel coronavirus (COVID-19), a sustained global pandemic has emerged. Globally, the cumulative death toll is in the millions. The rising number of COVID-19 infections and deaths has severely impacted the lives of people worldwide, healthcare systems, and economic development. We conducted a retrospective analysis of the characteristics of COVID-19 patients. This analysis includes clinical features upon initial hospital admission, relevant laboratory test results, and imaging findings. We aimed to identify risk factors for severe illness and to construct a predictive model for assessing the risk of severe COVID-19. We collected and analyzed electronic medical records of confirmed COVID-19 patients admitted to the Affiliated Hospital of Jiangsu University (Zhenjiang, China) between December 18, 2022, and February 28, 2023. According to the WHO diagnostic criteria for the novel coronavirus, we divided the patients into two groups: severe and non-severe, and compared their clinical, laboratory, and imaging data. Logistic regression analysis, the least absolute shrinkage and selection operator (LASSO) regression, and receiver operating characteristic (ROC) curve analysis were used to identify the relevant risk factors for severe COVID-19 patients. Patients were divided into a training cohort and a validation cohort. A nomogram model was constructed using the "rms" package in R software. Among the 346 patients, the severe group exhibited significantly higher respiratory rates, breathlessness, altered consciousness, neutrophil-to-lymphocyte ratio (NLR), and lactate dehydrogenase (LDH) levels compared to the non-severe group. Imaging findings indicated that the severe group had a higher proportion of bilateral pulmonary inflammation and ground-glass opacities compared to the non-severe group. NLR and LDH were identified as independent risk factors for severe patients. The diagnostic performance was maximized when NLR, respiratory rate (RR), and LDH were combined. Based on the statistical analysis results, we developed a COVID-19 severity risk prediction model. The total score is calculated by adding up the scores for each of the twelve independent variables. By mapping the total score to the lowest scale, we can estimate the risk of COVID-19 severity. In addition, the calibration plots and DCA analysis showed that the nomogram had better discrimination power for predicting the severity of COVID-19. Our results showed that the development and validation of the predictive nomogram had good predictive value for severe COVID-19.

[Effects of Long-term Biochar Addition on Denitrification N2O Emissions from Bacteria and Fungi in Paddy Soil].

Denitrification driven by bacteria and fungi is the main source of nitrous oxide （N2O） emissions from paddy soil. It is generally believed that biochar reduces N2O emissions by influencing the bacterial denitrification process, but the relevant mechanism of its impact on fungal denitrification is still unclear. In this study, the long-term straw carbonization returning experimental field in Changshu Agricultural Ecological Experimental Base of the Chinese Academy of Sciences was taken as the object. Through indoor anaerobic culture and molecular biology technology, the relative contributions of bacteria and fungi to denitrifying N2O production in paddy soil and the related microorganism mechanism were studied under different long-term biochar application amounts （blank, 2.25 t·hm-2, and 22.5 t·hm-2, respectively, expressed by BC0, BC1, and BC10）. The results showed that compared with that in BC0, biochar treatment significantly reduced N2O emission rate, denitrification potential, and cumulative N2O emissions, and the contribution of bacterial denitrification was greater than that of fungal denitrification in all three treatments. Among them, the relative contribution rate of bacterial denitrification in BC10 （62.9%） was significantly increased compared to BC0 （50.8%）, whereas the relative contribution rate of fungal denitrification in BC10 （37.1%） was significantly lower than that in BC0 （49.2%）. The application of biochar significantly increased the abundance of bacterial denitrification functional genes （nirK, nirS, and nosZ） but reduced the abundance of fungal nirK genes. The contribution rate of fungal denitrification was significantly positively correlated with the N2O emission rate and negatively correlated with soil pH, TN, SOM, and DOC. Biochar may have inhibited the growth of denitrifying fungi by increasing pH and carbon and nitrogen content, reducing the abundance of related functional genes, thereby weakening the reduction ability of NO to N2O during fungal denitrification process. This significantly reduces the contribution rate of N2O production during the fungal denitrification process and the denitrification N2O emissions from paddy soil. This study helps to broaden our understanding of the denitrification process in paddy soil and provides a theoretical basis for further regulating fungal denitrification N2O emissions.

[Effects of biochar combined with nitrification/urease inhibitors on soil active nitrogen emissions from subtropical paddy soils]. / ç”Ÿç‰©ç‚­é æ–½ç¡åŒ–/è„²é ¶æŠ‘åˆ¶å‰‚å¯¹äºšçƒ­å¸¦æ°´ç¨»åœŸæ´»æ€§æ°®æ°”ä½“æŽ’æ”¾çš„å½±å“.

We examined the effects of biochar and urease inhibitors/nitrification inhibitors on nitrification process, ammonia and N2O emission in subtropical soil, and determined the best combination of biochar with nitrification and urease inhibitors. This work could provide a theoretical basis for the mitigation of the negative environmental risk caused by reactive nitrogen gas in the application of nitrogen fertilizer. A indoor aerobic culture test was conducted with seven treatments [urea+biochar (NB), urea+nitrification inhibitor (N+NI), urea+urease inhibitor (N+UI), urea+nitrification inhibitor+urease inhibitor (N+NIUI), urea+nitrification inhibitor+biochar (NB+NI), urea+urease inhibitor+biochar (NB+UI), urea+nitrification inhibitor+urease inhibitor+biochar (NB+NIUI)] and urea (N) as the control. The dynamics of soil inorganic nitrogen content, N2O emission and the volatility of ammonia volatilization were observed under combined application of biochar with urease inhibitor (NBPT)/nitrification inhibitor (DMPP). The results showed that:1)Compared to the control (5.11 mg N·kg-1·d-1) during the incubation period, NB treatment significantly increased therate constant of nitrification by 33.9%, and N+NI treatment significantly reduced the nitrification rate constant by 22.9%. NB treatment significantly increased the abundance of ammonia oxidizing bacteria (AOB) by 56.0%. 2) Compared with N treatment, N+NI and NB+NI treatments signi-ficantly enhanced the cumulative emission of NH3 by 49%. The N+UI treatment reduced the cumulative loss of NH3. The inhibition effect of NB+UI treatment was more significant. 3) The emission rate of N2O was highest in the first 10 days after fertilization. The N2O emission under NB treatment was the earliest, and that of N treatment was the highest (5.87 µg·kg-1·h-1). The combined application of DMPP and NBPT performed the best in reducing soil N2O emission. We estimated global warming potential (GWP) of the direct N2O and indirect N2O (NH3) emissions. Compared with N treatments, N+NI and NB+NI treatments increased the GWP by 34.8% and 40.9%, respectively. While the NB and NB+UI treatments significantly reduced the GWP by 45.9% and 60.5%, the combination of biochar and urease inhibitor had the best effect on reduction of GWP of soil active nitrogen emissions.

[Rheumatic valvular surgery and concomitant radiofrequency Maze procedure: TGF-ß1 mRNA expression predicting the efficacy].

OBJECTIVES: To investigate the relationship of the transforming growth factor beta1 (TGF-ß1) mRNA expression in atrial myocardium and the effectiveness of radiofrequency Maze procedure in patients with rheumatic valvular disease (RHD) and permanent atrial fibrillation (AF). METHODS: Between January 2008 and September 2008, 40 patients with RHD and AF underwent a radiofrequency Maze procedure with concomitant valvular surgery. The patients were assigned to normal sinus rhythm (SR) group (group A) and persistence AF group (group B) according to the results of the 6-month follow-up. Another 10 patients with SR and RHD undergone valvular surgery alone were assigned to control group (group C). Left atrial appendage were obtained in all patients. Expressions of TGF-ß1 mRNA were detected by semiquantitative RT-PCR technique. CVF-I and CVF-III were observed by sirius red staining. RESULTS: At 6-month follow-up, there were 28 patients in group A and 12 in group B. Patients in group A and group B had higher mRNA expressions of TGF-ß1, CVF-I and CVF-I/CVF-III compared with group C (P < 0.05). Also, the group B had higher mRNA expressions of TGF-ß1, CVF-I and CVF-I/CVF-III than group A (P < 0.05). The patients who had return of functional atrial contraction in group A had lower mRNA expression than the non-return patients (39 ± 12 vs. 60 ± 12, P < 0.05). The TGF-ß1 mRNA expression had a correlation with both the contents of CVF-I and left atrial diameter (r = 0.786, P < 0.05; r = 0.858, P < 0.05). Multiple logistic regression analysis revealed that the risk factors which independently associated with the postoperative persistence of atrial fibrillation at 6-month follow-up includes mRNA expression levels of TGF-ß1 (OR = 1.13, 95%CI 1.05 - 1.18, P = 0.031), CVF-I (OR = 1.07, 95%CI 1.00 - 1.13, P = 0.037) and lett atrial diameter (OR = 2.23, 95%CI 1.08 - 4.59, P = 0.042). CONCLUSIONS: The atrial TGF-ß1 mRNA expression level could predict the persistence of AF and the return of the functional atrial contraction at 6-month follow-up in patients who underwent rheumatic valvular surgery and concomitant radiofrequency Maze procedure.

[Influence of Antibiotics on the Denitrification Process of Antibiotic Resistant Denitrifying Bacteria and the Analysis of Microbial Community Structure].

The removal rate of some antibiotics in urban sewage by conventional treatment is low, which leads to an increase in antibiotic resistant bacteria in natural water environments. To reduce the ecological harm of antibiotics to the water in towns, a risk control technique for degradation of microantibiotics by the co-metabolism of antibiotic resistant denitrifying bacteria was proposed. Using sodium acetate as an electron donor and maintaining the concentration of ofloxacin (OFLX) at 1 µg·g-1, gradually increasing the dominant growth of antibiotic degradation bacteria, denitrifying bacteria (DnB1), trace antibiotics and sodium acetate, and denitrifying bacteria (DnB2) with the presence of sodium acetate and nitrogen elements were cultured. The degradation effect of antibiotics through denitrification and the effects of antibiotics on denitrification of resistant denitrifying bacteria and the changes to the microbial community were investigated. The results showed that DnB2 had a significant degradation effect on OFLX compared to DnB1. The degradation to OFLX by DnB1 and DnB2 was 0.31 µg·g-1 and 16.14 µg·g-1, respectively. Increased OFLX concentration inhibited DnB1 denitrification activity in the short term. The denitrification process of DnB2 was less affected by OFLX. At the same time, high-throughput sequencing using the Illumina MiSeq platform was used. Based on the operational taxonomic unit information formed by the clustering of sequencing results, the diversity of each sample was compared and analyzed. The research results show that the relative abundance and diversity of the microbial community of DnB1 are higher than those of DnB2.

[Effects of biochar on ammonia volatilization from farmland soil: A review.] / ç”Ÿç‰©ç‚­å¯¹å†œç”°åœŸå£¤æ°¨æŒ¥å‘çš„å½±å“æœºåˆ¶ç ”ç©¶è¿›å±•.

Reducing soil ammonia volatilization is one of the key ways to reduce soil nitrogen loss and improve nitrogen utilization efficiency in farmlands. Biochar has unique physico-chemical pro-perties, which can change soil physical and chemical properties, affect soil nitrogen cycle, and affect ammonia volatilization in farmland soil. Firstly, we reviewed the ammonia volatilization process and its influencing factors (climatic condition, soil environment, and fertilization management, etc.) in paddy fields and upland fields. Then, research progress on the impacts of biochar on ammonia volatilization from farmland ecosystem was reviewed. Furthermore, the mechanisms underlying the responses of ammonia volatilization to biochar intervention were discussed from the aspects of physical adsorption, gas-liquid equilibrium, and biochemical progress regulation. The reduction of soil ammonia volatilization is mainly based on the adsorption of soil NH4+ and NH3 by oxygen-containing functional groups on the surface of biochar and the promotion of soil nitrification. How-ever, the increases of soil ammonia volatilization are mainly related to the increases of soil pH, air permeability, activities of microorganisms related with soil organic nitrogen mineralization. Finally, the research direction of reducing soil ammonia volatilization and improving nitrogen utilization efficiency by biochar was prospected.

Co-assembly of HPV capsid proteins and aggregation-induced emission fluorogens for improved cell imaging.

In order to improve the cell-imaging ability, and particularly, to extend the bio-application of AIEgen, human papillomavirus (HPV) capsid protein L1 was assembled with the complex of DNA and aggregation-induced emission fluorogen 9,10-distyrylhydrazine (DSAI), where the virus-like particles (VLPs) of HPV encapsulate the complex via electrostatic interaction. The co-assembled nanoparticles, DSAI-DNA@VLPs, showed homogeneous size (∼53 nm), enhanced fluorescence (8 × 2.5-fold), considerable stability (anti-DNase digestion), improved biocompatibility and commendable protection for the DSAI-DNA complex, ensuring virtual brighter imaging in live cells, both for HeLa and normal 293T cell lines.

[Effects of biochar addition on enzyme activity and fertility in paddy soil after six years]. / 施用生物炭6å¹´åŽå¯¹ç¨»ç”°åœŸå£¤é ¶æ´»æ€§åŠè‚¥åŠ›çš„å½±å“.

A field experiment was conducted to examine the effects on soil fertility and enzyme activities in paddy field after six years of one-split rice straw-derived biochar [0 (BC0), 7.5(BC1), 15(BC2), 22.5(BC3) t·hm-2] and rice straw (3.75 t·hm-2, STR) application. The results showed that soil organic carbon, available phosphorus and rapidly available potassium concentrations significantly increased, by 34.6%, 12.4% and 26.2%, respectively. Soil pH and soil bulk density were significantly reduced, but total nitrogen content had no significant difference compared with BC0. Biochar addition significantly increased the activities of soil urease and acid phosphatase. The soil fluorescein diacetate (FDA hydrolase) and arylsulfatase activity were inhibited to varying degrees. Among them, BC2 treatment increased soil urease activity by 36.5%. The soil acid phosphatase activity increased with the increases of biochar application rate, which was positively correlated with soil available phosphorus concentration. FDA hydrolase and urease activity had positive correlation with soil available potassium content, while soil acid phosphatase and arylsulfatase activity had positive correlation with soil bulk density. After six years, soil dehydrogenase and polyphenol oxidase activity significantly increased by 48.8% and 27.5%, respectively, while catalase activity significantly decreased when compared with control BC0. STR treatment increased activities of soil urease, FDA hydrolase, dehydrogenase, acid phosphatase and arylsulfatase significantly, while decreased the catalase and polyphenol oxidase activities by 23.4% and 15.9%, respectively.

[Stability of biochar and the mechanisms underlying its response to mineral modification: A review.] / ç”Ÿç‰©ç‚­çš„ç¨³å®šæ€§åŠå ¶å¯¹çŸ¿ç‰©æ”¹æ€§çš„å“åº”æœºåˆ¶ç ”ç©¶è¿›å±•.

Biochar, with high degree of carbon stability, is considered as a kind of carbon sequestration material that can effectively alleviate the greenhouse effect. It is of great significance for carbon sequestration and mitigation to develop biochar with high carbon retention and stability. Mineral modification can regulate the stability of biochar. However, the relevant research has not received enough attention, and the underlying mechanism is not very clear. Firstly, the evaluation indices of biochar stability were summarized, mainly including H/C atomic ratio, O/C atomic ratio, coefficient of stability R50, volatile-matter content, thermal weight loss rate of carbon, carbon (chemical) oxidation loss rate, and cumulative CO2 emission of microbial mineralization. Then, based on the analysis of impact factors of biochar stability (such as raw material type, carbonization condition, external environment, etc.), we reviewed research progress about the effects of mineral modification on biochar stability. Furthermore, possible mechanisms of both enhancement and weakening effects on biochar stability were put forward. Enhancement is mainly due to the effects of physical barrier of minerals and the organic mineral complex formed by the interaction of mineral and biochar. While weakening effect is mainly due to special mineral composition, such as the Fe-bearing mineral composition, which promotes the thermal decomposition of biochar at high temperature. Finally, future research directions were proposed, in order to promote the development of carbon sequestration technology of biochar and provide technical support and theoretical basis for obtaining more stable biochar.

Heavy metals and PAHs in sewage sludge from twelve wastewater treatment plants in Zhejiang province.

OBJECTIVE: To investigate the heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) in sludge of twelve wastewater treatment plants (WWTPs) in Zhejiang province of China, and to assess their potential for land application. METHODS: Sludge was collected from 12 WWTPs within the province. GC-MS and AAS were used to measure PAHs and HMs contents in sludge. RESULTS: Concentrations of HMs in most of the sludge samples were below the regulatory limits for the sludge to be used in agriculture in China with the exception of Zn in 2 sludge samples and Cd in 1 sample. All 16 PAHs, targeted by the USEPA agency, were found in the sludge from the twelve plants with a total concentration ranging from 33.73 mg kg(-1) to 82.58 mg kg(-1) (dry weight, d.w.). The levels of Sigma9 PAHs varied from 13.87 mg kg(-1) to 61.86 mg kg(-1) (d.w.) in the sludge, far exceeding the limitation value recommended by the Europe Union. The concentration and composition of PAHs in sewage sludge varied and depended mainly on the quantity and type of industrial wastewater accepted by the WWTPs. A significant relationship between the proportion of industrial wastewater received by WWTPs and the total content of 16 PAHs in the sludge was observed. CONCLUSION: PAHs have become one of the primary pollutants in sludge of Zhejiang WWTPs instead of HMs. It is, therefore, essential to reduce the contents of PAHs before the sludge can be used in agriculture through proper treatment.

[Cadmium adsorption by biochar prepared from pyrolysis of silk waste at different temperatures]. / 不同炭化温度制备的蚕丝被废弃物生物炭对重金属Cd2+的吸附性能.

In this study, biochars (BC300, BC500 and BC700) were produced from silk waste through pyrolysis under oxygen-limited condition at 300, 500 and 700 ℃, respectively. The physicochemical properties of biochar were detected by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD) and specific surface area analyzer. The Cd2+ adsorption capacities of biochars were investigated. Results showed that BET surface area, pH, and ash were increased with the increases of pyrolysis temperature. SEM images showed that the surfaces of biochars were rough and irregular. XRD and FT-IR results showed that all the silk waste biochars obtained at different temperatures contained calcite. pH had limited influence on the removal efficiency of biochar for Cd2+. Langmuir isotherm fitted the experimental data quite well. The Langmuir monolayer adsorption capacity of BC300, BC500, and BC700 were 25.61, 52.41, and 91.07 mg·g-1, respectively. The adsorption of Cd2+ onto the biochars obeyed a pseudo second-order kinetic model, with the BC700 showing the best removal efficiency. Further-more, the effects of the ionic strength and coexisting cations on Cd2+ removal were investigated. The results showed that the removal of Cd2+ was decreased with the increases of NaCl. Among the coexisting cations, the removal of Cd2+ was decreased by Ca2+ and Mg2+, while K+ had limited effect on the removal of Cd2+. In conclusion, the biochar derived from silk waste pyrolysis is a potential attractive adsorbent for the removal of Cd2+ from water.

Cell receptor screening for human papillomavirus invasion by using a polyoxometalate-peptide assembly as a probe.

The present study constructed a competitive recognition system using cell receptor screening for human papillomavirus (HPV) invasion by using the hybrid-assembly of polyoxometalates (POMs) and cationic peptides as a platform. The fine tuning both of the surface charge of POMs and peptide sequence were precisely performed to develop a luminescence switch of POMs, leading to the establishment of a ternary system to identify which types of glycosaminoglycans (GAGs) are potential cell receptors for HPV infection. In addition, the method was successfully applied to construct a hybrid-assembly with the recombined HPV 16 L1 pentamers from Escherichia coli and perform GAGs screening, which validated the system's potential for practical applications. In particular, the intrinsic mechanism for each competitive partner in the system was explained well by using isothermal titration calorimetry (ITC) and time-resolved fluorescence spectra. The present method will be helpful to extend the protocol to other systems by using peptides and POMs with similar properties, and ultimately, we hope it will promote the development of anti-viral agents.

Simultaneous removal of Sb(iii) and Cd(ii) in water by adsorption onto a MnFe2O4-biochar nanocomposite.

In this study, a jacobsite-biochar nanocomposite (MnFe2O4-BC) was fabricated and used to simultaneously remove Sb(iii) and Cd(ii) from water via adsorption. The MnFe2O4-BC nanocomposite was prepared via a co-precipitation method and analyzed using various techniques. The results confirm the successful decoration of the biochar surface with MnFe2O4 nanoparticles. The maximum Sb(iii) removal efficiency was found to be higher from bi-solute solutions containing Cd(ii) than from single-solute systems, suggesting that the presence of Cd(ii) enhances the removal of Sb(iii). The Langmuir isotherm model describes well Sb(iii) and Cd(ii) removal via adsorption onto the MnFe2O4-BC nanocomposite. The maximum adsorption capacities are 237.53 and 181.49 mg g-1 for Sb(iii) and Cd(ii), respectively, in a bi-solute system. Thus, the prepared MnFe2O4-BC nanocomposite is demonstrated to be a potential adsorbent for simultaneously removing Sb(iii) and Cd(ii) ions from aqueous solutions.

[Priming effect of biochar on the minerialization of native soil organic carbon and the mechanisms: A review.] / ç”Ÿç‰©ç‚­å¯¹åœŸå£¤æœ‰æœºç¢³çŸ¿åŒ–çš„æ¿€å‘æ•ˆåº”åŠå ¶æœºç†ç ”ç©¶è¿›å±•.

In recent years, studies on carbon sequestration of biochar in soil has been in spotlight owing to the specific characteristics of biochar such as strong carbon stability and well developed pore structure. However, whether biochar will ultimately increase soil carbon storage or promote soil carbon emissions when applied into the soil? This question remains controversial in current academic circles. Further research is required on priming effect of biochar on mineralization of native soil organic carbon and its mechanisms. Based on the analysis of biochar characteristics, such as its carbon composition and stability, pore structure and surface morphology, research progress on the priming effect of biochar on the decomposition of native soil organic carbon was reviewed in this paper. Furthermore, possible mechanisms of both positive and negative priming effect, that is promoting and suppressing the mineralization, were put forward. Positive priming effect is mainly due to the promotion of soil microbial activity caused by biochar, the preferential mineralization of easily decomposed components in biochar, and the co-metabolism of soil microbes. While negative priming effect is mainly based on the encapsulation and adsorption protection of soil organic matter due to the internal pore structure and the external surface of biochar. Other potential reasons for negative priming effect can be the stabilization resulted from the formation of organic-inorganic complex promoted by biochar in the soil, and the inhibition of activity of soil microbes and its enzymes by biochar. Finally, future research directions were proposed in order to provide theoretical basis for the application of biochar in soil carbon sequestration.

[Effects of biochar on soil nutrients leaching and potential mechanisms: A review].

Controlling soil nutrient leaching in farmland ecosystems has been a hotspot in the research field of agricultural environment. Biochar has its unique physical and chemical properties, playing a significant role in enhancing soil carbon storage, improving soil quality and increasing crop yield. As a kind of new exogenous material, biochar has the potential in impacting soil nutrient cycling directly or indirectly, and has profound influences on soil nutrient leaching. This paper analyzed the intrinsic factors affecting how biochar affects soil nutrient leaching, such as the physical and chemical properties of biochar, and the interaction between biochar and soil organisms. Then the latest literatures regarding the external factors, including biochar application rates, soil types, depth of soil layer, fertilization conditions and temporal dynamics, through which biochar influences soil nutrient (especially nitrogen and phosphorus) leaching were reviewed. On that basis, four related action mechanisms were clarified, including direct adsorption of nutrients by biochar due to its micropore structure or surface charge, influencing nutrient leaching through increasing soil water- holding capacity, influencing nutrient cycling through the interaction with soil microbes, and preferential transport of absorbed nutrients by fine biochar particles. At last future research directions for better understanding the interactions between biochar and nutrient leaching in the soil were proposed.

[Effects of biochar application on greenhouse gas emission from paddy soil and its physical and chemical properties].

A field experiment was conducted to investigate the effects of rice straw returning and rice straw biochar and life rubbish biochar application on the greenhouse gas (CH4, CO2 and N2O) emission from paddy soil, its physical and chemical properties, and rice grain yield. Compared with rice straw returning, applying rice straw biochar decreased the cumulative CH4 and N2O emissions from paddy soil significantly by 64.2% - 78.5% and 16.3% - 18.4%, respectively. Whether planting rice or not, the cumulative N2O emission from paddy soil under the applications of rice straw biochar and life rubbish biochar was decreased significantly, compared with that without biochar amendment. Under the condition of no rice planting, applying life rubbish biochar reduced the cumulative CO2 emission significantly by 25.3%. Rice straw biochar was superior to life rubbish biochar in improving soil pH and available potassium content. Both rice straw biochar and life rubbish biochar could increase the soil organic carbon content significantly, but had less effects on the soil bulk density, total nitrogen and available phosphorus contents, cation exchange capacity (CEC), and grain yield. It was suggested that compared with rice straw returning, straw biochar was more effective in improving rice grain yield.

[Nitrogen loss and its control during livestock manure composting].

Composting is an effective way to realize livestock manure treatment and recycling. However, the nitrogen loss during manure composting is relatively serious. Studies on this nitrogen loss and its control could provide theoretic basis and practical reference for efficient nitrogen loss control. This paper described the nitrogen transformation and the main nitrogen loss ways during the composting, and summarized the main factors (including raw material characteristics, environment factors, and technological conditions) affecting the nitrogen loss in the composting. In addition, the research progress in the nitrogen loss control, including adjusting carbon and nitrogen metabolism, changing nitrogen form, adding ammonia adsorbent, and controlling pile aeration and temperature, was reviewed, and the prospects for future research were presented.

[Environmental behavior and effect of biomass-derived black carbon in soil: a review].

Biomass-derived black carbon, also named biochar, has the characteristics of high stability against decay and high capability of adsorption, and can affect the environment through its interactions with climate and geology, playing a significant role in global climate change, carbon biogeochemical cycle, and environmental system. In recent years, more and more researchers in the fields of atmospheric sciences, geology, and environmental science focused on the environmental behavior and effect of biochar. As one possible source of the components with high aromatic structure in soil humus, biochar is of great importance in increasing soil carbon storage and improving soil fertility, and in maintaining the balance of soil ecosystem. This paper offered the latest information regarding the characteristics and biotic and abiotic oxidation mechanisms of biochar, its effects on global climate change, and the environmental effect of biochar in soil. Research prospects were briefly discussed on the environmental behavior and effect of biochar in soil ecosystem.