Search

There have been reports about anomalies in mobile geomagnetic data before earthquakes; however, whether it can be used as an indicator for identifying potential earthquake areas was not be explored. In this study, we propose two parameters for earthquake forecasting based on annual mobile geomagnetic observation data. The spatial horizontal and three components' changes are calculated in each year and then used to forecast moderate–large earthquakes (M ≥ 5.0) in southwest China in the subsequent period. It is found that earthquakes are more likely to occur in low H- or F-value regions. We statistically assess their forecasting performance by using Molchan's error diagram, and the results indicate that there is considerable precursory information in the spatial H and F values. It is concluded that mobile geomagnetic observations might be useful in middle-term earthquake forecasts in the study area. We discuss the physical mechanisms of H and F values to explain their reasonability. The methodology proposed in this study could be helpful in finding out the optimal solution for annual mobile geomagnetic measurements for middle-term earthquake forecasting. [ABSTRACT FROM AUTHOR]

Background: Xanthomonas oryzae (Xo) is one of the important pathogenic bacterial groups affecting rice production. Its pathovars Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) cause bacterial blight and bacterial leaf streak in rice, respectively. Xo infects host plants by relying mainly on its transcription activator-like effectors (TALEs) that bind to host DNA targets, named effector binding elements (EBEs), and induce the expression of downstream major susceptibility genes. Blocking TALE binding to EBE could increase rice resistance to the corresponding Xo. Findings: We used CRISPR/Cas9 to edit the EBEs of three major susceptibility genes (OsSWEET11, OsSWEET14 and OsSULTR3;6) in the rice varieties Guihong 1 and Zhonghua 11. Both varieties have a natural one-base mutation in the EBE of another major susceptibility gene (OsSWEET13) which is not induced by the corresponding TALE. Two rice lines GT0105 (from Guihong 1) and ZT0918 (from Zhonghua 11) with target mutations and transgene-free were obtained and showed significantly enhanced resistance to the tested strains of Xoo and Xoc. Furthermore, under simulated field conditions, the morphology and other agronomic traits of GT0105 and ZT0918 were basically the same as those of the wild types. Conclusions: In this study, we first reported that the engineering rice lines obtained by editing the promoters of susceptibility genes are resistant to Xoo and Xoc, and their original agronomic traits are not affected. [ABSTRACT FROM AUTHOR]

The Gram-negative bacterium Xanthomonas oryzae pv. oryzicola (Xoc) is the causal agent of rice bacterial leaf streak (BLS), one of the most destructive diseases of rice (Oryza sativa L.) that is the important staple crop. Xoc can invade host leaves via stomata and wounds and its type three secretion system (T3SS) is pivotal to its pathogenic lifestyle. In this study, using a novel dual RNA-seq approach, we examined transcriptomes of rice and Xoc in samples inoculated with wild type Xoc GX01 and its T3SS defective strain (T3SD), to investigate the global transcriptional changes in both organisms. Compared with T3SD strain, rice inoculated with wild type Xoc GX01 resulted in significant expression changes of a series of plant defence related genes, including ones altered in plant signalling pathway, and downregulated in phenylalanine metabolism, flavonoid and momilactone biosynthesis, suggesting repression of plant defence response and reduction in both callose deposition and phytoalexin accumulation. Also, some known transcription activator-like effector (TALE) targets were induced by Xoc GX01, e.g. OsSultr3;6 which contributes to rice susceptibility. Some cell elongation related genes, including several expansin genes, were induced by GX01 too, suggesting that Xoc may exploit this pathway to weaken cell wall strength, beneficial for bacterial infection. On the other hand, compared with wild type, the T3SD strain transcriptome in planta was characterized by downregulation of ATP, protein and polysaccharide synthesis, and upregulation of antioxidation and detoxification related genes, revealing that T3SD strain faced serious starvation and oxidation stresses in planta without a functional T3SS. In addition, comparative global transcript profiles of Xoc in planta and in medium revealed an upregulation of virulence factor synthesis and secretion in planta in favour of bacterial infection. Collectively, this study provides a comprehensive representation of cross talk between the host and bacterial pathogen, revealing insights into the Xoc-rice pathogenic dynamic and reveals novel strategies exploited by this important pathogen to cause disease. [ABSTRACT FROM AUTHOR]

There is a growing trend toward considering municipal solid waste (MSW) with a large organic fraction as a source of renewable energy using a dry anaerobic digestion (AD) process. Pre-aeration is effective in improving the dry AD of MSW. However, due to a lack of information regarding the modification of organic components during pre-aeration and the relationship with the subsequent AD, the mechanisms and optimum strength of this process remain unclear. In this study, the role of different short-term pre-aeration durations (4, 8, and 14 days) in dry AD of MSW was evaluated in batch-tests, with a focus on changes in the organic components during pre-aeration and their impact on the subsequent spectral evolution of dissolved organic matter (DOM) and bulk performance. Dry AD of MSW operated effectively after the 8-day pre-aeration. The accelerated degradation of proteins during pre-aeration is critical for the subsequent AD, by reducing the organic loading and providing a buffer for the ammonia generated. A favorable methanogenesis, facilitated by pre-aeration, rapidly decreased protein-like fluorescent matter by ∼2.8 times, by converting it to stable humic- and fulvic-like groups. MSW with an 8-day pre-aeration produced the highest biogas yield (192.4 NL/kg dry matter), representing ∼24.9% of the initial carbon recovered as methane. Excessive pre-aeration of 14 days decreased the biogas yield by ∼33%. An insufficient pre-aeration led to an excessive butyric-type acidification, with protein-like matter dominating the bulk DOM (∼81% of total fluorescence intensity). Multivariate analysis methods confirmed that spectroscopic indicators could evaluate the stability of dry AD. [ABSTRACT FROM AUTHOR]

Waste management is a major source of greenhouse gas (GHG) emissions and provides an opportunity to reduce carbon emissions that has yet to be fully exploited. The total GHG emissions in the waste management sector in China is quite different from that in developed countries, mainly due to the high biodegradable fraction (almost 60–70%) of municipal solid waste (MSW). Based on the above characteristics of MSW and its current and future management strategies, five typical scenarios were modeled by the EaseTech software to compare GHG emissions under different scenarios. These strategies were evaluated by life cycle assessment (LCA) and sensitivity analysis. The two scenarios of landfilling, either with LFG flaring or with LFG to energy, would cause very high GHG emissions (259.5 kgCO 2 -Eq/t and 169.0 kgCO 2 -Eq/t, respectively) due to the rapid degradation and low efficiency of landfill gas (LFG) collection. Incineration with energy recovery would lower total GHG emissions (−17.5 kgCO 2 -Eq/t) substantially. However, the auxiliary fuel needed would offset its environmental benefit. Two scenarios, anaerobic digestion (AD) of the source-separated organic fractions and residue landfilling, and AD of the source-separated organic fractions and incineration of the fractions with high calorific value, followed by residue landfilling, would result in significant carbon sinks (−27.7 kgCO 2 -Eq/t and −54.8 kgCO 2 -Eq/t, respectively). From the perspective of GHG emissions reduction, the optimum technical route of MSW in China would be AD of the source-separated organic fractions, incineration of the fractions with high calorific value, followed by residue landfilling. [ABSTRACT FROM AUTHOR]

Pre-aeration is effective on regulating subsequent anaerobic degradation of municipal solid waste (MSW) with high organic fractions during landfilling. The strength of pre-aeration should be optimized to intentionally remove some easily biodegradable fractions while conserve bio-methane potential as much as possible. This study investigates the evolution of organic components in MSW during 2–14 days pre-aeration process and its impacts on subsequent anaerobic degradation in simulated landfill bioreactors. Results showed that a 6-day pre-aeration enabled to develop a thermophilic stage, which significantly accelerated biodegradation of organics except lignocelluloses, with removal rates of 42.8%, 76.7% and 25.1% for proteins, carbohydrates and lipids, respectively. Particularly, ammonia from accelerated ammonification in the thermophilic stage neutralized VFAs generated from anaerobic landfilling. As a result, the MSW with 6-day pre-aeration obtained the highest methane yield 123.4 NL/kg dry matter. Therefore, it is recommended to interrupt pre-aeration before its cooling stage to switch to anaerobic landfilling. [ABSTRACT FROM AUTHOR]

The conventional synthesis of porous carbon materials is primarily relied on the activation and template process. This work successfully develops a one-step method for preparing amorphous porous carbon nanoparticles (APCNs) with a high specific surface area (SSA) in organic solvents under ambient atmosphere. The APCNs are formed mainly by the reaction of ferrocene with ammonium chloride at only 180 °C for 1 h in different solvents. Several ferrocene derivatives and KOH activation are also utilized to improve the textural properties of the APCNs. It is found that the high solubility of (C 5 H 5) 2 Fe and FeCl 3 ·6H 2 O in a solvent is the most essential factor associated with the decrease of carbon nanoparticle size. The smaller the nanoparticle size, the larger the SSA of APCNs. The APCNs prepared in phenoxyethanol have a median size of 32.74 nm, exhibiting an SSA of 689 m2/g. The high solubility of NH 4 Cl can also contribute to reducing the nanoparticle size. The binary solvent consisting of phenoxyethanol and glycol has an excellent solubility for (C 5 H 5) 2 Fe, FeCl 3 ·6H 2 O, and NH 4 Cl, in which the prepared APCNs have a median size 11.48 nm and a higher SSA of 936 m2/g. Besides, the benzoyl substituted group on the cyclopentadiene can facilitate formation of small mesopores. The oxygen and nitrogen are in situ doped in the APCNs. Activation is also effective, and the SSA of APCNs reaches a maximum value of 1575 m2/g at a KOH ratio of 2:1. The solvent-based synthesis is unique and competitive in terms of high efficiency and energy conservation. [Display omitted] • A novel liquid-phase method for preparing amorphous porous carbon nanoparticles is developed based on an oxidation mechanism. • The synthesis is carried out at ambient atmosphere at 180 °C. • The specific surface area and pore volume are 936.11 m2/g and 1.45 cm3/g, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Density functional theory has been used to investigate microscopic structures and electronic properties of LDHs containing F−, Cl−, Br−, I−, OH−, , , . Both electrovalent bonds and covalent bonds were found in the layer. For halogen anions, the strength of interaction was accorded with electronegative intensity. And the LUMOs dispersed throughout the interlayer region. While for complicated anions, the strength was accorded with the discrepancy of electronegative intensity between center atom and bonding atoms, the LUMOs almost localized in interlayer anions. p Orbital of metal cations and s orbital of anions provided major contributions to electrovalent parts of system, while s orbital of metal cations and p orbital of anions provided major contributions to covalent parts. This has the further significance in Forcefield design for LDHs simulation. Multiple hydrogen bonds were existed in LDHs-X system. The more the number of multiple hydrogen bonds formed, the weaker the strength of single multi-hydrogen bonds was. Multiple hydrogen bonds will bring stronger interaction between interlayer guest anion and host LDHs-layer than single hydrogen bond. [Copyright &y& Elsevier]

Abstract: Zn/Al layered double hydroxides (LDHs) were intercalated with the anionic antihypertensive drugs Enalpril, Lisinopril, Captopril and Ramipril by using coprecipitation or ion-exchange technique. TG–MS analyses suggested that the thermal stability of Ena−, Lis− (arranged with monolayer, resulted from X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) analysis was enhanced much more than Cap– and Ram– (arranged with bilayer). The release studies show that the release rate of all samples markedly decreased in both pH 4.25 and 7.45. However, the release time of Ena–, Lis– were much longer compared with Cap–, Ram– in both pH 4.25 and 7.45, it is possible that the intercalated guests, arranged with monolayer in the interlayer, show lesser repulsive force and strong affinity with the LDH layers. And the release data followed both the Higuchi-square-root law and the first-order equation well. Based on the analysis of batch release, intercalated structural models as well as the TG–DTA results, we conclude that for drug–LDH, stronger the affinity between intercalated anions and the layers is, better the thermal property and the stability to the acid attack of drug–LDH, and the intercalated anions are easier apt to monolayer arrangement within the interlayer, were presented. [Copyright &y& Elsevier]

Abstract: Adsorption of a weak acid dye, methyl orange (MO) by calcined layered double hydroxides (LDO) with Zn/Al molar ratio of 3:1 was investigated. In the light of so called “memory effect,” LDO was found to recover their original layered structure in the presence of appropriate anions, after adsorption part of MO− and CO2− 3 (come from air) intercalated into the interlayer of LDH which had been supported by XRD and ICP. The results of adsorption experiments indicate that the maximum capacity of MO at equilibrium () and percentage of adsorption (η%) with a fixed adsorbent dose of 0.5 g L−1 were found to be 181.9 mg g−1 and 90.95%, respectively, when MO concentration, temperature, pH and equilibrium time were 100 mg L−1, 298 K, 6.0 and 120 min, respectively. The isotherms showed that the adsorption of MO by Zn/Al-LDO was both consistent with Langmuir and Freundlich equations. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model. The calculated value of was found to be 77.1 kJ mol−1, which suggests that the process of adsorption of methyl orange is controlled by the rate of reaction rather than diffusion. The possible mechanism for MO adsorption has also been presumed. In addition, the competitive anions on adsorption and the regeneration of Zn/Al-LDO have also been investigated. [Copyright &y& Elsevier]

Highlights: [•] Different Ti-based LDH materials with good crystal structure have been synthesized. [•] The band gap of LDH materials follow the order: Zn/Ti>CeO2/ZnTi>Zn/Al–Ti/SB. [ • ] The degradation performance of MO/MB follow the order: CeO2/ZnTi>Zn/Al–Ti/SB>Zn/Ti. [•] Mechanism and intermediates for photocatalytic degradation on MO has been presumed. [•] Zn/Al–Ti/SB–LDHs after MO/MB degradation was feasible at least three cycles. [Copyright &y& Elsevier]

Highlights: [•] Zn/M–NO3-LDHs (Al, Fe, Ti, and Fe/Ti) have been synthesized. [•] The band gap of LDH materials followed the order: Zn/Fe>Zn/Fe/Ti>Zn/Ti>Zn/Al. [•] The photocatalytic performance by four materials: Zn/Ti>Zn/Al>Zn/Fe/Ti>Zn/Fe. [•] The mechanism for photocatalytic degradation on Rhodamine B has also been presumed. [•] Zn/Ti–NO3-LDHs after RB degradation were feasible at least three cycles. [Copyright &y& Elsevier]

Abstract: We report a facile route using precipitation reaction and sequential calcination to synthesize three-dimensional (3D) flower-like magnesium borate (Mg3B2O6) nanoarchitectures with poly(vinyl pyrrolidone) (PVP) as the template. The structure and morphology were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM). The results indicate that 3D flower-like Mg3B2O6 microspheres with diameters of 0.6–1.0μm are composed of large numbers of single crystalline nanosheets with thickness of about 10nm. The N2 sorption result and pore-size distribution analysis show that mesopores and macropores exist in the 3D flower-like nanostructures. The mesopores and macropores will endow the hierarchical microspheres with novel application potentials. [Copyright &y& Elsevier]

• Overall, synergism was observed across all temperature ranges (25–52 °C). • PC can be used for VFA production at temperature of ≥42 °C. • Optimized temperature for PWC, FWC and OFMSW were 52, 37 and 42 °C respectively. • Mainly, acetic and butyric acids were produced from PC at 52 °C and FC at 37 °C. This study explores individual contributions and synergistic effects of food and paper, main components of organic fraction of municipal solid waste (OFMSW) towards volatile fatty acids (VFA) fermentation under different temperatures (25, 37, 42 and 52 °C). Thanks to the synergism of food and paper component (FC & PC), the results revealed that OFMSW is suitable for VFA production. Maximum VFA production was noticed to be 21.5 mg/L at 42 °C, ~2.1, and 1.42 times higher than fermentation of PC and FC. Enhanced hydrolysis of PC occurred at >37 °C, increasing alkalinity in leachate to 6.7 g/L at 42 °C, thus maintaining a stable pH (5.4–5.6) during acidogenic fermentation. Additionally, 74% of COD is hydrolyzed, of which 79% is converted to VFA based on biodegradable carbon at 42 °C. It is suggested that co-existence of FC and PC can enhance VFA production of OFMSW, and targeted VFA production can be maximized through process optimization. [ABSTRACT FROM AUTHOR]

Xanthomonas oryzae pv. oryzicola (Xoc) depends on its type III secretion system (T3SS) to translocate type III secreted effectors (T3SEs), including transcription activator-like effectors (TALEs) and non-transcription activator-like effectors (non-TALEs), into host cells. T3SEs can promote the colonization of Xoc and contribute to virulence by manipulating host cell physiology. We annotated 25 genes encoding non-TALEs in Xoc strain GX01, an isolate from Guangxi in the South China's rice growing region. Through systematic mutagenesis of non-TALEs, we found that xopN , the virulence contribution of which was previously unknown for Xoc , significantly contributes to the virulence of Xoc GX01, as does avrBs2. [ABSTRACT FROM AUTHOR]

Initial bulk density (IBD) is an important variable in anaerobic digestion since it defines and optimizes the treatment capacity of a system. This study reveals the mechanism on how IBD might affect anaerobic digestion of waste. Four different IBD values: D 1 (500–700 kg m −3 ), D 2 (900–1000 kg m −3 ), D 3 (1100–1200 kg m −3 ) and D 4 (1200–1400 kg m −3 ) were set and tested over a period of 90 days in simulated landfill reactors. The main variables affected by the IBD are the methane generation, saturation degree, extraction of organic matter, and the total population of methanogens. The study identified that IBD >1000 kg m −3 may have significant effect on methane generation, either prolonging the lag time or completely inhibiting the process. This study provides a new understanding of the anaerobic digestion process in saturated high-solids systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • GHG emissions from an industrial-scale AD plant were assessed. • The AD process before digestate treatment achieved carbon offset. • Electricity consumption caused the major GHG emissions. • Waste oil recovery and biogas reuse are pivotal for offsetting GHG emissions. • Net GHG emissions from digestate process varies with different final disposal ways. Anaerobic digestion (AD) has been widely applied for treating organic waste and is known as a carbon-offsetting process. However, most studies relied on laboratory-scale experiments or literature to calculate carbon emissions from AD process, and the impact of digestate processing was overlooked. This study assessed the carbon footprint for an industrial food waste co-digestion plant with operational data. The results indicated that carbon emission before digestate treatment is −88.5 ± 4.4 kg CO 2 -eq/t. The major source of carbon emission is electricity provision, followed by fuel combustion, unburned biogas, and fugitive gas emissions, while waste oil recovery and biogas utilization offset the carbon emissions. Considering digestate treatment and disposal options, the plant's net carbon emissions are as follows: −86.1 ± 6.2 kg CO 2 -eq/t (incineration) < -80.7 ± 6.5 kg CO 2 -eq/t (land application) < 6.7 ± 12.2 kg CO 2 -eq/t (landfilling). This work aims at providing a roadmap for making site-specific calculations of the carbon footprint for AD process. [ABSTRACT FROM AUTHOR]

Landfill odors have created a major concern for the Chinese public. Based on the combination of a first order decay (FOD) model and a ground-level point source Gaussian dispersion model, the impacts from odors emitted from the 1955 landfills in China are evaluated in this paper. Our bottom-up approach uses basic data related to each landfill to achieve a more accurate and comprehensive understanding of impact of landfill odors. Results reveal that the average radius of impact of landfill odors in China is 796 m, while most landfills (46.85%) are within the range of 400–1000 m, in line with the results from previous studies. The total land area impacted by odors has reached 837,476 ha, accounting for 0.09% of China's land territory. Guangdong and Sichuan provinces have the largest land areas impacted by odors, while Tibet Autonomous Region and Tianjin Municipality have the smallest. According to the CALPUFF (California Puff) model and an analysis of social big data, the overall uncertainty of our calculation of the range of odor impacts is roughly −32.88% to 32.67%. This type of study is essential for gaining an accurate and detailed estimation of the affected human population and will prove valuable for addressing the current Not In My Back Yard (NIMBY) challenge in China. [ABSTRACT FROM AUTHOR]