Lonicera japonica Thunb. is a typical medicinal and edible plant in China. It has antibacterial, anti-oxidant, anti-endotoxin, and anti-inflammatory effects, etc. Its pharmacological action is closely related to its a...Lonicera japonica Thunb. is a typical medicinal and edible plant in China. It has antibacterial, anti-oxidant, anti-endotoxin, and anti-inflammatory effects, etc. Its pharmacological action is closely related to its active components. Based on the results of previous studies, this paper summarized the effects of variety, origin, cultivation conditions, pruning, harvesting period and processing methods on the active components of L. japonica , in the hope of providing theoretical guidance for high-yield and high-quality cultivation of L. japonica.展开更多
The radiative transfer equations in cylindrical coordinates are important in the application of inertial confinement fusion.In comparison with the equations in Cartesian coordinates,an additional angular derivative te...The radiative transfer equations in cylindrical coordinates are important in the application of inertial confinement fusion.In comparison with the equations in Cartesian coordinates,an additional angular derivative term appears in the cylindrical case.This term adds great difficulty for a numerical scheme to keep the conservation of total energy.In this paper,based on weighting factors,the angular derivative term is properly discretized,and the interface fluxes in the radial r-direction depend on such a discretization as well.A unified gas kinetic scheme(UGKS)with asymptotic preserving property for the gray radiative transfer equations is constructed in cylindrical coordinates.The current UGKS can naturally capture the radiation diffusion solution in the optically thick regime with the cell size being much larger than photon's mean free path.At the same time,the current UGKS can present accurate solutions in the optically thin regime as well.Moreover,it is a finite volume method with total energy conservation.Due to the scale-dependent time evolution solution for the interface flux evaluation,the scheme can cover multiscale transport mechanism seamlessly.The cylindrical hohlraum tests in inertial confinement fusion are used to validate the current approach,and the solutions are compared with implic让Monte Carlo result.展开更多
Crowdfunding is an innovative strategy for financing a new business venture from the general public instead of seeking funds in traditional ways,such as issuing bonds or bank lending.This study aims to identify the de...Crowdfunding is an innovative strategy for financing a new business venture from the general public instead of seeking funds in traditional ways,such as issuing bonds or bank lending.This study aims to identify the determinants affecting the success of a crowdfunding campaign and how different measurements for crowdfunding success,different crowdfunding models,and the selection of subdivided determinants influ-ence the determinants’impacts on crowdfunding success.We set the disciplines in the search strategy to select studies related to crowdfunding success.Ultimately,94 empirical papers are selected to reveal the different findings for the determinants of crowdfunding success;based on this information,we construct an integrated framework for future research.There has been much research on project-and creator-related factors;however,many of these factors have inconsistent relationships with crowdfunding success due to varying measurements of success.In particular,different measurements used within the same study for determinants or crowdfunding success may also produce inconsistent results.In addition,different crowdfunding models of a project have been found to induce additional findings.Our review of the determinants of crowdfunding success and the definitions of the determinants,as well as the proposed integrated framework,can help focus future work on relatively new or unique determinants rarely addressed in the existing literature.This work provides practical implications for both theory and practice,and directions for future research.展开更多
The contents of chlorogenic acid and luteoloside in Flos Lonicerae from Binhai New Area and Jinnan District of Tianjin were determined to provide basis for the quality identification of this medicinal material. The co...The contents of chlorogenic acid and luteoloside in Flos Lonicerae from Binhai New Area and Jinnan District of Tianjin were determined to provide basis for the quality identification of this medicinal material. The content of chlorogenic acid was determined by HPLC. In Flos Lonicerae from Binhai New Area and in Flos Lonicerae harvested at different stages from Jinnan District,the contents of chlorogenic acid were 3. 804%,5. 507%( three green stage),4. 855%( silver flower stage) and 4. 220%( golden flower stage),respectively,and the contents of luteoloside were 5. 53%,12. 405%( three green stage),14. 370%( silver flower stage) and 0. 917%( golden flower stage),respectively. The contents of chlorogenic acid in Flos Lonicerae from Jinnan District were higher than that from Binhai New Area. Among different stages,the content of chlorogenic acid was highest in three green stage,followed by that in silver flower stage. As the flowers bloomed,the content of chlorogenic acid in the medicinal material showed a significant downward trend. In Flos Lonicerae from Jinnan District,the content of luteoloside was highest in silver flower stage and lowest in golden flower stage.展开更多
Dear Editor,Base editing has been developed to be one of the effective CRISPR-based gene editing techniques(Rees and Liu,2018).Base editors(BEs)take advantage of DNAmodifying enzymes fused with a catalytically impaire...Dear Editor,Base editing has been developed to be one of the effective CRISPR-based gene editing techniques(Rees and Liu,2018).Base editors(BEs)take advantage of DNAmodifying enzymes fused with a catalytically impaired CRISPR protein to install base mutations.In BE,DNA-modifying enzymes often process nontarget singlestranded DNA(NTS)generated by Cas proteins.展开更多
Antibiotic resistance genes(ARGs)are an emerging issue for drinkingwater safety.However,the seasonal variation of ARGs in drinking water distribution systems(DWDS)is still unclear.This work revealed the tempo-spatial ...Antibiotic resistance genes(ARGs)are an emerging issue for drinkingwater safety.However,the seasonal variation of ARGs in drinking water distribution systems(DWDS)is still unclear.This work revealed the tempo-spatial changes of microbial community,ARGs,mobile genetic elements(MGEs)co-occurring with ARGs,ARG hosts in DWDS bulk water by means of metagenome assembly.The microbial community and antibiotic resistome varied with sampling season and site.Temperature,ammonia,chlorite and total plate count(TPC)drove the variations of microbial community structure.Moreover,environmental parameters(total organic carbon(TOC),chlorite,TPC and hardness)shifted antibiotic resistome.ARGs and MGEs co-occurring with ARGs showed higher relative abundance in summer and autumn,which might be attributed to detached pipe biofilm.In particular,ARG-bacitracin and plasmid were the predominant ARG and MGE,respectively.ARG hosts changed with season and site and were more diverse in summer and autumn.In winter and spring,Limnohabitans and Mycobacterium were the major ARG hosts as well as the dominant genera in microbial community.In addition,in summer and autumn,high relative abundance of Achromobacter and Stenotrophomonas were the hosts harboring many kinds of ARGs and MGEs at site in a residential zone(0.4 km from the water treatment plant).Compared with MGEs,microbial community had a greater contribution to the variation of antibiotic resistome.This work gives new insights into the dynamics of ARGs in full-scale DWDS and the underlying factors.展开更多
Membrane separation, as an important drinking water treatment technology, has wide applications. The remarkable advantages of ceramic membranes, such as chemical stability, thermal stability, and high mechanical stren...Membrane separation, as an important drinking water treatment technology, has wide applications. The remarkable advantages of ceramic membranes, such as chemical stability, thermal stability, and high mechanical strength, endow them with broader prospects for development. Despite the importance and advantages of membrane separation in water treatment, the technique has a limitation: membrane fouling, which greatly lowers its effectiveness. This is caused by organics, inorganic substances, and microorganisms clogging the pore and polluting the membrane surface. The increase in membrane pollution greatly lowers purification effectiveness. Controlling membrane fouling is critical in ensuring the efficient and stable operation of ceramic membranes for water treatment. This review analyzes four mechanisms of ceramic membrane fouling, namely complete blocking, standard blocking, intermediate blocking, and cake filtration blocking. It evaluates the mechanisms underlying ceramic membrane fouling and summarizes the progress in approaches aimed at controlling it. These include ceramic membrane pretreatment, ceramic membrane surface modification, membrane cleaning, magnetization, ultrasonics, and nanobubbles. This review highlights the importance of optimizing ceramic membrane preparation through further research on membrane fouling and pre-membrane pretreatment mechanisms. In addition, combining process regulations with ceramic membranes as the core is an important research direction for ceramic membrane-based water treatment.展开更多
Microbial activity and regrowth in drinking water distribution systems is a major concern for water service companies.However,previous studies have focused on the microbial composition and diversity of the drinkingwat...Microbial activity and regrowth in drinking water distribution systems is a major concern for water service companies.However,previous studies have focused on the microbial composition and diversity of the drinkingwater distribution systems(DWDSs),with little discussion on microbial molecular ecological networks(MENs)in different water supply networks.MEN analysis explores the potentialmicrobial interaction and the impact of environmental stress,to explain the characteristics of microbial community structures.In this study,the random matrix theory-based network analysis was employed to investigate the impact of seasonal variation including water source switching on the networks of three DWDSs that used different disinfection methods.The results showed that microbial interaction varied slightly with the seasons but was significantly influenced by different DWDSs.Proteobacteria,identified as key species,play an important role in the network.Combined UV-chlorine disinfection can effectively reduce the size and complexity of the network compared to chlorine disinfection alone,ignoring seasonal variations,which may affect microbial activity or control microbial regrowth in DWDSs.This study provides new insights for analyzing the dynamics of microbial interactions in DWDSs.展开更多
辐射输运方程的数值模拟在天体物理、武器物理和惯性约束与磁约束聚变等研究中都起着非常重要的作用.在实际问题中,背景介质的不透明度系数决定了辐射光子在其中的传输行为.光性薄(不透明度系数小)的介质对辐射光子是透明的,光子与背景...辐射输运方程的数值模拟在天体物理、武器物理和惯性约束与磁约束聚变等研究中都起着非常重要的作用.在实际问题中,背景介质的不透明度系数决定了辐射光子在其中的传输行为.光性薄(不透明度系数小)的介质对辐射光子是透明的,光子与背景介质的相互作用弱,光子传输具有输运传播性质;而光性厚(不透明度系数大)的介质对辐射光子是不透明的,光子与背景介质的相互作用强,光子传输具有扩散性质.因此在辐射输运方程的计算中,如何设计既能得到光子输运传播性质又能捕捉光子扩散传播性质的渐近保持离散格式是目前一个非常活跃和前沿的研究方向.本文简要介绍近几年在辐射输运方程的渐近保持统一气体动理学格式(unified gas kinetic scheme,UGKS)研究方面的进展.本文主要以灰体辐射输运方程为例,详细介绍UGKS的构造方法并给出其渐近分析.同时,结合角度有限元方法和球谐函数展开的方法,介绍如何减弱/去除基于离散纵标法的UGKS具有射线效应的问题,以及相应的改进渐近保持格式.此外,也介绍了将渐近保持的UGKS应用拓展到考虑流体运动的完全辐射流体力学方程组.最后,用一些数值例子验证了格式的渐近保持性和保正性等性质.展开更多
Characterization, treatment and releases of eight polybrominated diphenyl ethers (PBDEs) congeners and sixteen polycyclic aromatic hydrocarbons (PAHs) in wastewater were evaluated along the treatment processes of ...Characterization, treatment and releases of eight polybrominated diphenyl ethers (PBDEs) congeners and sixteen polycyclic aromatic hydrocarbons (PAHs) in wastewater were evaluated along the treatment processes of a typical secondary treatment municipal sewage treatment plant (STP) (in Hefei City) situated the beside Nanfei River, East China. The findings showed that the average concentrations of the total PBDEs in raw wastewater and treated effluent were 188.578 and 36.884 ng/L respectively. Brominated diphenyl ether (BDE) 209 congener, the predominant PBDE in the STP and Nanfei River, could be related to the discharge of car-industry-derived wastes. For PAHs, the average concentrations in raw wastewater and treated effluent were 5758.8 and 2240.4 ng/L respectively, with naphthalene, benzo[a]pyrene and indeno[1,2,3-c,d]pyrene being detected at the highest concentrations. PAHs mainly originate from the combustion of biomass/coal and petroleum. The STP reduced about 80% of the PBDEs and 61% of the PAHs, which were eliminated mainly by sedimentation processes. The removal rates of PBDEs/PAHs increased with the increase of their solid-water partitioning coefficients. Accordingly, the STP's effluent, containing some PBDE congeners (e.g., BDE 47, 99 and 209, etc.) and low-molecular-weight PAHs, could be an important contributor of these contaminants' input to Nanfei River. It resulted in a significant increase of PBDE/PAH concentrations and PAH toxicological risk in the river water downstream. About 4.040 kg/yr of PBDEs and 245.324 kg/yr of PAHs could be released into the Nanfei River. The current conventional wastewater treatment processes should be improved to remove the relatively low-molecular-weight PBDEs/PAHs more effectively.展开更多
Dear Editor,Recent study shows that the prime editing system fusing the Cas9 nickase and reverse transcriptase could perform all types ofgene modifications,including basesubstitutions(transitionsand transversions),sma...Dear Editor,Recent study shows that the prime editing system fusing the Cas9 nickase and reverse transcriptase could perform all types ofgene modifications,including basesubstitutions(transitionsand transversions),small insertions,and deletions,without requiringdonor DNA or double-strand breaks(DSBs)(Anzalone et al.,2019).Despite the accuracy and versatility,the efficiencyof the prime editor(PE)is often insufficient,which limits its broadapplications.展开更多
Seasonal algal blooms of Lake Yangcheng highlight the necessity to develop an effective and optimal water treatment process to enhance the removal of algae and dissolved organic matter (DOM). In the present study, the...Seasonal algal blooms of Lake Yangcheng highlight the necessity to develop an effective and optimal water treatment process to enhance the removal of algae and dissolved organic matter (DOM). In the present study, the coagulation performance for the removal of algae, turbidity, dissolved organic carbon (DOC) and ultraviolet absorbance at 254 nm (UV254) was investigated systematically by central composite design (CCD) using response surface methodology (RSM). The regression models were developed to illustrate the relationships between coagulation performance and experimental variables. Analysis of variance (ANOVA) was performed to test the significance of the response surface models. It can be concluded that the major mechanisms of coagulation to remove algae and DOM were charge neutralization and sweep flocculation at a pH range of 4.66–6.34. The optimal coagulation conditions with coagulant dosage of 7.57 mg Al/L, pH of 5.42 and initial algal cell density of 3.83 × 106 cell/mL led to removal of 96.76%, 97.64%, 40.23% and 30.12% in term of cell density, turbidity, DOC and UV254 absorbance, respectively, which were in good agreement with the validation experimental results. A comparison between the modeling results derived through both ANOVA and artificial neural networks (ANN) based on experimental data showed a high correlation coefficient, which indicated that the models were significant and fitted well with experimental results. The results proposed a valuable reference for the treatment of algae-laden surface water in practical application by the optimal coagulation-flocculation process.展开更多
The efficacy of ultraviolet(UV)disinfection has been validated in numerous studies by using culturebased methods.However,the discovery of viable but non-culturable bacteria has necessitated the investigation of UV dis...The efficacy of ultraviolet(UV)disinfection has been validated in numerous studies by using culturebased methods.However,the discovery of viable but non-culturable bacteria has necessitated the investigation of UV disinfection based on bacterial viability parameters.We used quantitative polymerase chain reaction(qPCR)to investigate DNA damage and evaluated adenosine triphosphate(ATP)to indicate bacterial viability.The results of qPCR effectively showed the DNA damage induced by UV when using longer gene amplicons,in that sufficiently long amplicons of both 16S and gadA indicated that the UV induced DNA damages.The copy concentrations of the long amplicons of 16S and gadA decreased by 2.38 log/mL and 1.88 log/mL,respectively,after exposure to 40 mJ/cm^2 lowpressure UV.After UV exposure,the ATP level in the bacteria did not decrease instantly.Instead it decreased gradually at a rate that was positively related to the UV fluence.For low-pressure UV,this rate of decrease was slow,but for medium pressure UV,this rate of decrease was relatively high when the UV fluence reached 40 mJ/cm^2.At the same UV fluence,the ATP level in the bacteria decreased at a faster rate after exposure to medium-pressure UV.展开更多
Optimizing the characteristics of granular activated carbon(GAC)can improve the performance of biologically activated carbon(BAC)filters,and iodine value has always been the principal index for GAC selection.However,i...Optimizing the characteristics of granular activated carbon(GAC)can improve the performance of biologically activated carbon(BAC)filters,and iodine value has always been the principal index for GAC selection.However,in this study,among three types of GAC treating the same humic acidcontaminated water,one had an iodine value 35%lower than the other two,but the dissolved organic carbon removal efficiency of its BAC was less than 5%away from the others.Iodine value was found to influence the removal of different organic fractions instead of the total removal efficiency.Based on the removal and biological characteristics,two possible mechanisms of organic matter removal during steady-state were suggested.For GAC with poor micropore volume and iodine value,high molecular weight substances(3500–9000 Da)were removed mainly through degradation by microorganisms,and the biodegraded organics(soluble microbial by-products,<3500 Da)were released because of the low adsorption capacity of activated carbon.For GAC with higher micropore volume and iodine value,organics with low molecular weight(<3500 Da)were more easily removed,first being adsorbed by micropores and then biodegraded by the biofilm.The biomass was determined by the pore volume with pore diameters greater than 100μm,but did not correspond to the removal efficiency.Nevertheless,the microbial community structure was coordinate with both the pore structure and the organic removal characteristics.The findings provide a theoretical basis for selecting GAC for the BAC process based on its pore structure.展开更多
To manage potential microbial risks and meet increasingly strict drinking water health standards,UV treatment has attracted increasing attention for use in drinking water systems in China.However,the effects of UV tre...To manage potential microbial risks and meet increasingly strict drinking water health standards,UV treatment has attracted increasing attention for use in drinking water systems in China.However,the effects of UV treatment on microbial control and disinfection byproducts(DBPs)formation in real municipal drinking water systems are poorly understood.Here,we collected water samples from three real drinking water systems in Beijing and Tianjin to investigate the impacts of UV treatment on microbial control and DBP formation.We employed heterotrophic plate count(HPC),flow cytometry(FCM),quantitative PCR analysis,and high-throughput sequencing to measure microorganisms in the samples.Different trends were observed between HPC and total cell count(measured by FCM),indicating that a single indicator could not reflect the real degree of biological re-growth in drinking water distribution systems(DWDSs).A significant increase in the 16S rRNA gene concentration was observed when the UV system was stopped.Besides,the bacterial community composition was similar at the phylum level but differed markedly at the genera level among the three DWDSs.Some chlorine-resistant bacteria,including potential pathogens(e.g.,Acinetobacter)showed a high relative abundance when the UV system was turned off.It can be concluded that UV treatment can mitigate microbial re-growth to some extent.Finally,UV treatment had a limited influence on the formation of DBPs,including trihalomethanes,haloacetic acids,and nitrogenated DBPs.The findings of this study may help to understand the performance of UV treatment in real drinking water systems.展开更多
Hemin can improve the stress resistance of plants through the heme oxygenase system.Additionally,substances contained in plants,such as secondary metabolites,can improve stress resistance.However,few studies have expl...Hemin can improve the stress resistance of plants through the heme oxygenase system.Additionally,substances contained in plants,such as secondary metabolites,can improve stress resistance.However,few studies have explored the effects of hemin on secondary metabolite content.Therefore,the effects of hemin on saponin synthesis and the mechanism of plant injury relief by hemin in Conyza blinii were investigated in this study.Hemin treatment promoted plant growth and increased the antioxidant enzyme activity and saponin content of C.blinii under osmotic stress and cold stress.Further study showed that hemin could provide sufficient precursors for saponin synthesis by improving the photosynthetic capacity of C.blinii and increasing the gene expression of key enzymes in the saponin synthesis pathway,thus increasing the saponin content.Moreover,the promotion effect of hemin on saponin synthesis is dependent on heme oxygenase-1 and can be reversed by the inhibitor Zn-protoporphyrin-IX(ZnPPIX).This study revealed that hemin can increase the saponin content of C.blinii and alleviate the damage caused by abiotic stress,and it also broadened the understanding of the relationship between hemin and secondary metabolites in plant abiotic stress relief.展开更多
Advanced water treatment is commonly used to remove micropollutants such as pesticides,endocrine disrupting chemicals,and disinfection byproducts in modem drinking water treatment plants.However,little attention has b...Advanced water treatment is commonly used to remove micropollutants such as pesticides,endocrine disrupting chemicals,and disinfection byproducts in modem drinking water treatment plants.However,little attention has been paid to the changes in the genotoxicity of substances remaining in the water following the different water treatment processes.In this study,samples were collected from three drinking water treatment plants with different treatment processes.The treated water from each process was analyzed and compared for genotoxicity and the formation of organic compounds.The genotoxicity was evaluated by an umu test,and the acute and chronic toxicity was analyzed through Ecological Structure-Activity Relationship(ECOSAR).The results of the umu test indicated that biological activated carbon reduced the genotoxicity by 38%,77%,and 46%in the three drinking water treatment plants,respectively,while chlorination increased the genotoxicity.Gas chromatograph-mass spectrometry analysis revealed that halogenated hydrocarbons and aromatic compounds were major contributors to genotoxicity.The results of ECOSAR were not consistent with those of the umu test.Therefore,we conclude that genotoxicity cannot be determined using ECOSAR.展开更多
A hallmark of adaptive evolution is innovation in gene function,which is associated with the development of distinct roles for genes during plant evolution;however,assessing functional innovation over long periods of ...A hallmark of adaptive evolution is innovation in gene function,which is associated with the development of distinct roles for genes during plant evolution;however,assessing functional innovation over long periods of time is not trivial.Tartary buckwheat(Fagopyrum tataricum)originated in the Himalayan region and has been exposed to intense UV-B radiation for a long time,making it an ideal species for studying novel UV-B response mechanisms in plants.Here,we developed a workflow to obtain a co-functional network of UV-B responses using data from more than 10,000 samples in more than 80 projects with multi-species and multiomics data.Dissecting the entire network revealed that flavonoid biosynthesis was most significantly related to the UV-B response.Importantly,we found that the regulatory factor MYB4R1,which resides at the core of the network,has undergone neofunctionalization.In vitro and in vivo experiments demonstrated that MYB4R1 regulates flavonoid and anthocyanin accumulation in response to UV-B in buckwheat by binding to L-box motifs in the FtCHS,FtFLS,and FtUFGT promoters.We used deep learning to develop a visual discrimination model of buckwheat flavonoid content based on natural populations exposed to global UV-B radiation.Our study highlights the critical role of gene neofunctionalization in UV-B adaptation.展开更多
In this paper,we consider the multi-dimensional asymptotic preserving unified gas kinetic scheme for gray radiative transfer equations on distorted quadrilateral meshes.Different from the former scheme [J.Comput.Phys....In this paper,we consider the multi-dimensional asymptotic preserving unified gas kinetic scheme for gray radiative transfer equations on distorted quadrilateral meshes.Different from the former scheme [J.Comput.Phys.285(2015),265-279] on uniform meshes,in this paper,in order to obtain the boundary fluxes based on the framework of unified gas kinetic scheme(UGKS),we use the real multi-dimensional reconstruction for the initial data and the macro-terms in the equation of the gray transfer equations.We can prove that the scheme is asymptotic preserving,and especially for the distorted quadrilateral meshes,a nine-point scheme [SIAM J.SCI.COMPUT.30(2008),1341-1361] for the diffusion limit equations is obtained,which is naturally reduced to standard five-point scheme for the orthogonal meshes.The numerical examples on distorted meshes are included to validate the current approach.展开更多
The efficacy of ultraviolet(UV)disinfection has been analyzed and validated by numerous studies using culture-based methods,yet the discovery of the viable but nonculturable state necessitates the investigation of UV ...The efficacy of ultraviolet(UV)disinfection has been analyzed and validated by numerous studies using culture-based methods,yet the discovery of the viable but nonculturable state necessitates the investigation of UV disinfection based on viability parameters.Paired regulators of the SOS response system,recA-lexA,and the programmed cell death system,mazEF,in Escherichia coli were chosen as the target genes,and the effect of UV irradiation on the mRNAs of the four genes was studied.This research showed that,after UV irradiation,the responses of the mRNAs were highly consistent,with reduction percentages of approximately 60% at 20 mJ/cm2,70% at 40 mJ/cm2,and 90% at 80 mJ/cm2,and these reductions were believed to be the result of direct UV damage to nucleic acids.After 24 h of dark incubation,recA and lexA were both upregulated but to a lesser extent for repressor lexA;and mazE and mazF were both downregulated.This result implies that UV irradiation induces the dark repair system more actively,and the cells will proceed to death at a rate similar to that associated with natural decay.展开更多
基金Supported by Science and Technology Planning Project of Tianjin(17JCYBJC29800&16PTZSTG00020)Science and Technology Planning Project of Jinnan District of Tianjin(201802055)Science and Technology Planning Project of Binhai New Area of Tianjin(BHXQKJXM-SF-2018-33)
文摘Lonicera japonica Thunb. is a typical medicinal and edible plant in China. It has antibacterial, anti-oxidant, anti-endotoxin, and anti-inflammatory effects, etc. Its pharmacological action is closely related to its active components. Based on the results of previous studies, this paper summarized the effects of variety, origin, cultivation conditions, pruning, harvesting period and processing methods on the active components of L. japonica , in the hope of providing theoretical guidance for high-yield and high-quality cultivation of L. japonica.
文摘The radiative transfer equations in cylindrical coordinates are important in the application of inertial confinement fusion.In comparison with the equations in Cartesian coordinates,an additional angular derivative term appears in the cylindrical case.This term adds great difficulty for a numerical scheme to keep the conservation of total energy.In this paper,based on weighting factors,the angular derivative term is properly discretized,and the interface fluxes in the radial r-direction depend on such a discretization as well.A unified gas kinetic scheme(UGKS)with asymptotic preserving property for the gray radiative transfer equations is constructed in cylindrical coordinates.The current UGKS can naturally capture the radiation diffusion solution in the optically thick regime with the cell size being much larger than photon's mean free path.At the same time,the current UGKS can present accurate solutions in the optically thin regime as well.Moreover,it is a finite volume method with total energy conservation.Due to the scale-dependent time evolution solution for the interface flux evaluation,the scheme can cover multiscale transport mechanism seamlessly.The cylindrical hohlraum tests in inertial confinement fusion are used to validate the current approach,and the solutions are compared with implic让Monte Carlo result.
基金supported by the National Natural Science Foundation of China[Grant numbers 71801063,71850013,91846301,72071038].
文摘Crowdfunding is an innovative strategy for financing a new business venture from the general public instead of seeking funds in traditional ways,such as issuing bonds or bank lending.This study aims to identify the determinants affecting the success of a crowdfunding campaign and how different measurements for crowdfunding success,different crowdfunding models,and the selection of subdivided determinants influ-ence the determinants’impacts on crowdfunding success.We set the disciplines in the search strategy to select studies related to crowdfunding success.Ultimately,94 empirical papers are selected to reveal the different findings for the determinants of crowdfunding success;based on this information,we construct an integrated framework for future research.There has been much research on project-and creator-related factors;however,many of these factors have inconsistent relationships with crowdfunding success due to varying measurements of success.In particular,different measurements used within the same study for determinants or crowdfunding success may also produce inconsistent results.In addition,different crowdfunding models of a project have been found to induce additional findings.Our review of the determinants of crowdfunding success and the definitions of the determinants,as well as the proposed integrated framework,can help focus future work on relatively new or unique determinants rarely addressed in the existing literature.This work provides practical implications for both theory and practice,and directions for future research.
基金Supported by Tianjin Science and Technology Plan Project(18YFSDZC00020,17JCYBJC29800,16PTZSTG00020)Science and Technology Plan Project of Jinnan District,Tianjin City(201802055)+2 种基金Science and Technology Project of Binhai New Area,Tianjin City(BHXQKJXM-SF-2018-33)Graduate Innovation Training Program of Tianjin Agricultural University(2017YPY007)College Students'Innovative Entrepreneurial Training Program of Tianjin City(201910061059).
文摘The contents of chlorogenic acid and luteoloside in Flos Lonicerae from Binhai New Area and Jinnan District of Tianjin were determined to provide basis for the quality identification of this medicinal material. The content of chlorogenic acid was determined by HPLC. In Flos Lonicerae from Binhai New Area and in Flos Lonicerae harvested at different stages from Jinnan District,the contents of chlorogenic acid were 3. 804%,5. 507%( three green stage),4. 855%( silver flower stage) and 4. 220%( golden flower stage),respectively,and the contents of luteoloside were 5. 53%,12. 405%( three green stage),14. 370%( silver flower stage) and 0. 917%( golden flower stage),respectively. The contents of chlorogenic acid in Flos Lonicerae from Jinnan District were higher than that from Binhai New Area. Among different stages,the content of chlorogenic acid was highest in three green stage,followed by that in silver flower stage. As the flowers bloomed,the content of chlorogenic acid in the medicinal material showed a significant downward trend. In Flos Lonicerae from Jinnan District,the content of luteoloside was highest in silver flower stage and lowest in golden flower stage.
基金supported by the National Natural Science Foundation of China(32022048,32271505)the Natural Science Foundation of Shanghai(22ZR1441900,23ZR1442200)the Key Research Project of Zhejiang Laboratory。
文摘Dear Editor,Base editing has been developed to be one of the effective CRISPR-based gene editing techniques(Rees and Liu,2018).Base editors(BEs)take advantage of DNAmodifying enzymes fused with a catalytically impaired CRISPR protein to install base mutations.In BE,DNA-modifying enzymes often process nontarget singlestranded DNA(NTS)generated by Cas proteins.
基金supported by the National Key R&D Program of China(No.2019YFC0408700).
文摘Antibiotic resistance genes(ARGs)are an emerging issue for drinkingwater safety.However,the seasonal variation of ARGs in drinking water distribution systems(DWDS)is still unclear.This work revealed the tempo-spatial changes of microbial community,ARGs,mobile genetic elements(MGEs)co-occurring with ARGs,ARG hosts in DWDS bulk water by means of metagenome assembly.The microbial community and antibiotic resistome varied with sampling season and site.Temperature,ammonia,chlorite and total plate count(TPC)drove the variations of microbial community structure.Moreover,environmental parameters(total organic carbon(TOC),chlorite,TPC and hardness)shifted antibiotic resistome.ARGs and MGEs co-occurring with ARGs showed higher relative abundance in summer and autumn,which might be attributed to detached pipe biofilm.In particular,ARG-bacitracin and plasmid were the predominant ARG and MGE,respectively.ARG hosts changed with season and site and were more diverse in summer and autumn.In winter and spring,Limnohabitans and Mycobacterium were the major ARG hosts as well as the dominant genera in microbial community.In addition,in summer and autumn,high relative abundance of Achromobacter and Stenotrophomonas were the hosts harboring many kinds of ARGs and MGEs at site in a residential zone(0.4 km from the water treatment plant).Compared with MGEs,microbial community had a greater contribution to the variation of antibiotic resistome.This work gives new insights into the dynamics of ARGs in full-scale DWDS and the underlying factors.
基金supported by the National Key R&D Program of China(No.2021YFC3201304).
文摘Membrane separation, as an important drinking water treatment technology, has wide applications. The remarkable advantages of ceramic membranes, such as chemical stability, thermal stability, and high mechanical strength, endow them with broader prospects for development. Despite the importance and advantages of membrane separation in water treatment, the technique has a limitation: membrane fouling, which greatly lowers its effectiveness. This is caused by organics, inorganic substances, and microorganisms clogging the pore and polluting the membrane surface. The increase in membrane pollution greatly lowers purification effectiveness. Controlling membrane fouling is critical in ensuring the efficient and stable operation of ceramic membranes for water treatment. This review analyzes four mechanisms of ceramic membrane fouling, namely complete blocking, standard blocking, intermediate blocking, and cake filtration blocking. It evaluates the mechanisms underlying ceramic membrane fouling and summarizes the progress in approaches aimed at controlling it. These include ceramic membrane pretreatment, ceramic membrane surface modification, membrane cleaning, magnetization, ultrasonics, and nanobubbles. This review highlights the importance of optimizing ceramic membrane preparation through further research on membrane fouling and pre-membrane pretreatment mechanisms. In addition, combining process regulations with ceramic membranes as the core is an important research direction for ceramic membrane-based water treatment.
基金supported by the National Key R&D Program of China (No. 2019YFC0408700)the National Science and Technology Major Projects of China (Nos. 2017ZX07108-002 and 2017ZX07502003)the funds from the National Natural Science Foundation of China (No. 51778323)
文摘Microbial activity and regrowth in drinking water distribution systems is a major concern for water service companies.However,previous studies have focused on the microbial composition and diversity of the drinkingwater distribution systems(DWDSs),with little discussion on microbial molecular ecological networks(MENs)in different water supply networks.MEN analysis explores the potentialmicrobial interaction and the impact of environmental stress,to explain the characteristics of microbial community structures.In this study,the random matrix theory-based network analysis was employed to investigate the impact of seasonal variation including water source switching on the networks of three DWDSs that used different disinfection methods.The results showed that microbial interaction varied slightly with the seasons but was significantly influenced by different DWDSs.Proteobacteria,identified as key species,play an important role in the network.Combined UV-chlorine disinfection can effectively reduce the size and complexity of the network compared to chlorine disinfection alone,ignoring seasonal variations,which may affect microbial activity or control microbial regrowth in DWDSs.This study provides new insights for analyzing the dynamics of microbial interactions in DWDSs.
文摘辐射输运方程的数值模拟在天体物理、武器物理和惯性约束与磁约束聚变等研究中都起着非常重要的作用.在实际问题中,背景介质的不透明度系数决定了辐射光子在其中的传输行为.光性薄(不透明度系数小)的介质对辐射光子是透明的,光子与背景介质的相互作用弱,光子传输具有输运传播性质;而光性厚(不透明度系数大)的介质对辐射光子是不透明的,光子与背景介质的相互作用强,光子传输具有扩散性质.因此在辐射输运方程的计算中,如何设计既能得到光子输运传播性质又能捕捉光子扩散传播性质的渐近保持离散格式是目前一个非常活跃和前沿的研究方向.本文简要介绍近几年在辐射输运方程的渐近保持统一气体动理学格式(unified gas kinetic scheme,UGKS)研究方面的进展.本文主要以灰体辐射输运方程为例,详细介绍UGKS的构造方法并给出其渐近分析.同时,结合角度有限元方法和球谐函数展开的方法,介绍如何减弱/去除基于离散纵标法的UGKS具有射线效应的问题,以及相应的改进渐近保持格式.此外,也介绍了将渐近保持的UGKS应用拓展到考虑流体运动的完全辐射流体力学方程组.最后,用一些数值例子验证了格式的渐近保持性和保正性等性质.
基金supported by the Mega-projects of Science Research for Water Environment Improvement(No.2009ZX07106-001,2012ZX07101-002)the National Natural Science Foundation of China(No.40901248)the China Basic Research Program(No.2008CB418206)
文摘Characterization, treatment and releases of eight polybrominated diphenyl ethers (PBDEs) congeners and sixteen polycyclic aromatic hydrocarbons (PAHs) in wastewater were evaluated along the treatment processes of a typical secondary treatment municipal sewage treatment plant (STP) (in Hefei City) situated the beside Nanfei River, East China. The findings showed that the average concentrations of the total PBDEs in raw wastewater and treated effluent were 188.578 and 36.884 ng/L respectively. Brominated diphenyl ether (BDE) 209 congener, the predominant PBDE in the STP and Nanfei River, could be related to the discharge of car-industry-derived wastes. For PAHs, the average concentrations in raw wastewater and treated effluent were 5758.8 and 2240.4 ng/L respectively, with naphthalene, benzo[a]pyrene and indeno[1,2,3-c,d]pyrene being detected at the highest concentrations. PAHs mainly originate from the combustion of biomass/coal and petroleum. The STP reduced about 80% of the PBDEs and 61% of the PAHs, which were eliminated mainly by sedimentation processes. The removal rates of PBDEs/PAHs increased with the increase of their solid-water partitioning coefficients. Accordingly, the STP's effluent, containing some PBDE congeners (e.g., BDE 47, 99 and 209, etc.) and low-molecular-weight PAHs, could be an important contributor of these contaminants' input to Nanfei River. It resulted in a significant increase of PBDE/PAH concentrations and PAH toxicological risk in the river water downstream. About 4.040 kg/yr of PBDEs and 245.324 kg/yr of PAHs could be released into the Nanfei River. The current conventional wastewater treatment processes should be improved to remove the relatively low-molecular-weight PBDEs/PAHs more effectively.
基金supported by the Emergency Key Program of Guangzhou Laboratory(EKPG21-18)the Leading Talents of Guangdong Province Program(608285568031).
文摘Dear Editor,Recent study shows that the prime editing system fusing the Cas9 nickase and reverse transcriptase could perform all types ofgene modifications,including basesubstitutions(transitionsand transversions),small insertions,and deletions,without requiringdonor DNA or double-strand breaks(DSBs)(Anzalone et al.,2019).Despite the accuracy and versatility,the efficiencyof the prime editor(PE)is often insufficient,which limits its broadapplications.
文摘Seasonal algal blooms of Lake Yangcheng highlight the necessity to develop an effective and optimal water treatment process to enhance the removal of algae and dissolved organic matter (DOM). In the present study, the coagulation performance for the removal of algae, turbidity, dissolved organic carbon (DOC) and ultraviolet absorbance at 254 nm (UV254) was investigated systematically by central composite design (CCD) using response surface methodology (RSM). The regression models were developed to illustrate the relationships between coagulation performance and experimental variables. Analysis of variance (ANOVA) was performed to test the significance of the response surface models. It can be concluded that the major mechanisms of coagulation to remove algae and DOM were charge neutralization and sweep flocculation at a pH range of 4.66–6.34. The optimal coagulation conditions with coagulant dosage of 7.57 mg Al/L, pH of 5.42 and initial algal cell density of 3.83 × 106 cell/mL led to removal of 96.76%, 97.64%, 40.23% and 30.12% in term of cell density, turbidity, DOC and UV254 absorbance, respectively, which were in good agreement with the validation experimental results. A comparison between the modeling results derived through both ANOVA and artificial neural networks (ANN) based on experimental data showed a high correlation coefficient, which indicated that the models were significant and fitted well with experimental results. The results proposed a valuable reference for the treatment of algae-laden surface water in practical application by the optimal coagulation-flocculation process.
基金This research was supported by the Chinese Major National R&D Project(Nos.2017ZX07108-003 and 2017ZX07502003).
文摘The efficacy of ultraviolet(UV)disinfection has been validated in numerous studies by using culturebased methods.However,the discovery of viable but non-culturable bacteria has necessitated the investigation of UV disinfection based on bacterial viability parameters.We used quantitative polymerase chain reaction(qPCR)to investigate DNA damage and evaluated adenosine triphosphate(ATP)to indicate bacterial viability.The results of qPCR effectively showed the DNA damage induced by UV when using longer gene amplicons,in that sufficiently long amplicons of both 16S and gadA indicated that the UV induced DNA damages.The copy concentrations of the long amplicons of 16S and gadA decreased by 2.38 log/mL and 1.88 log/mL,respectively,after exposure to 40 mJ/cm^2 lowpressure UV.After UV exposure,the ATP level in the bacteria did not decrease instantly.Instead it decreased gradually at a rate that was positively related to the UV fluence.For low-pressure UV,this rate of decrease was slow,but for medium pressure UV,this rate of decrease was relatively high when the UV fluence reached 40 mJ/cm^2.At the same UV fluence,the ATP level in the bacteria decreased at a faster rate after exposure to medium-pressure UV.
基金supported by the National Key R&D Program of China(No.2019YFC0408700)the funds from the National Natural Science Foundation of China(Grant Nos.51778323 and 51761125013)the National Science and Technology Major Projects of China(Nos.2012ZX07404-002,2017ZX07108-002,and 2017ZX07502003).
文摘Optimizing the characteristics of granular activated carbon(GAC)can improve the performance of biologically activated carbon(BAC)filters,and iodine value has always been the principal index for GAC selection.However,in this study,among three types of GAC treating the same humic acidcontaminated water,one had an iodine value 35%lower than the other two,but the dissolved organic carbon removal efficiency of its BAC was less than 5%away from the others.Iodine value was found to influence the removal of different organic fractions instead of the total removal efficiency.Based on the removal and biological characteristics,two possible mechanisms of organic matter removal during steady-state were suggested.For GAC with poor micropore volume and iodine value,high molecular weight substances(3500–9000 Da)were removed mainly through degradation by microorganisms,and the biodegraded organics(soluble microbial by-products,<3500 Da)were released because of the low adsorption capacity of activated carbon.For GAC with higher micropore volume and iodine value,organics with low molecular weight(<3500 Da)were more easily removed,first being adsorbed by micropores and then biodegraded by the biofilm.The biomass was determined by the pore volume with pore diameters greater than 100μm,but did not correspond to the removal efficiency.Nevertheless,the microbial community structure was coordinate with both the pore structure and the organic removal characteristics.The findings provide a theoretical basis for selecting GAC for the BAC process based on its pore structure.
基金supported by the National Natural Science Foundation of China(Nos.51778323,51761125013 and51290284)the National Science and Technology Major Project of China(Nos.2012ZX07404-002,2017ZX07108-003 and 2017ZX07502-003)
文摘To manage potential microbial risks and meet increasingly strict drinking water health standards,UV treatment has attracted increasing attention for use in drinking water systems in China.However,the effects of UV treatment on microbial control and disinfection byproducts(DBPs)formation in real municipal drinking water systems are poorly understood.Here,we collected water samples from three real drinking water systems in Beijing and Tianjin to investigate the impacts of UV treatment on microbial control and DBP formation.We employed heterotrophic plate count(HPC),flow cytometry(FCM),quantitative PCR analysis,and high-throughput sequencing to measure microorganisms in the samples.Different trends were observed between HPC and total cell count(measured by FCM),indicating that a single indicator could not reflect the real degree of biological re-growth in drinking water distribution systems(DWDSs).A significant increase in the 16S rRNA gene concentration was observed when the UV system was stopped.Besides,the bacterial community composition was similar at the phylum level but differed markedly at the genera level among the three DWDSs.Some chlorine-resistant bacteria,including potential pathogens(e.g.,Acinetobacter)showed a high relative abundance when the UV system was turned off.It can be concluded that UV treatment can mitigate microbial re-growth to some extent.Finally,UV treatment had a limited influence on the formation of DBPs,including trihalomethanes,haloacetic acids,and nitrogenated DBPs.The findings of this study may help to understand the performance of UV treatment in real drinking water systems.
基金supported by the Sichuan Science and Technology Program(No.2020YFH0136),China。
文摘Hemin can improve the stress resistance of plants through the heme oxygenase system.Additionally,substances contained in plants,such as secondary metabolites,can improve stress resistance.However,few studies have explored the effects of hemin on secondary metabolite content.Therefore,the effects of hemin on saponin synthesis and the mechanism of plant injury relief by hemin in Conyza blinii were investigated in this study.Hemin treatment promoted plant growth and increased the antioxidant enzyme activity and saponin content of C.blinii under osmotic stress and cold stress.Further study showed that hemin could provide sufficient precursors for saponin synthesis by improving the photosynthetic capacity of C.blinii and increasing the gene expression of key enzymes in the saponin synthesis pathway,thus increasing the saponin content.Moreover,the promotion effect of hemin on saponin synthesis is dependent on heme oxygenase-1 and can be reversed by the inhibitor Zn-protoporphyrin-IX(ZnPPIX).This study revealed that hemin can increase the saponin content of C.blinii and alleviate the damage caused by abiotic stress,and it also broadened the understanding of the relationship between hemin and secondary metabolites in plant abiotic stress relief.
基金This study was supported by the National Natural Science Foundation of China(Grant Nos.51778323,51761125013 and 51290284)the National Science and Technology Major Project of China(Grant Nos.2012ZX07404-002,2017ZX07108-003 and 2017ZX07502003).
文摘Advanced water treatment is commonly used to remove micropollutants such as pesticides,endocrine disrupting chemicals,and disinfection byproducts in modem drinking water treatment plants.However,little attention has been paid to the changes in the genotoxicity of substances remaining in the water following the different water treatment processes.In this study,samples were collected from three drinking water treatment plants with different treatment processes.The treated water from each process was analyzed and compared for genotoxicity and the formation of organic compounds.The genotoxicity was evaluated by an umu test,and the acute and chronic toxicity was analyzed through Ecological Structure-Activity Relationship(ECOSAR).The results of the umu test indicated that biological activated carbon reduced the genotoxicity by 38%,77%,and 46%in the three drinking water treatment plants,respectively,while chlorination increased the genotoxicity.Gas chromatograph-mass spectrometry analysis revealed that halogenated hydrocarbons and aromatic compounds were major contributors to genotoxicity.The results of ECOSAR were not consistent with those of the umu test.Therefore,we conclude that genotoxicity cannot be determined using ECOSAR.
基金sponsored by the National Key R&D Program of China(2021YFD1200105)the National Natural Science Foundation of China(3210150112)+2 种基金the Sichuan Province Science and Technology Support Program(2021YFH0086)the Shanghai Sailing Program(20YF1422000)the Startup Fund for Youngman Research at Shanghai Jiao Tong University(20X100040052).
文摘A hallmark of adaptive evolution is innovation in gene function,which is associated with the development of distinct roles for genes during plant evolution;however,assessing functional innovation over long periods of time is not trivial.Tartary buckwheat(Fagopyrum tataricum)originated in the Himalayan region and has been exposed to intense UV-B radiation for a long time,making it an ideal species for studying novel UV-B response mechanisms in plants.Here,we developed a workflow to obtain a co-functional network of UV-B responses using data from more than 10,000 samples in more than 80 projects with multi-species and multiomics data.Dissecting the entire network revealed that flavonoid biosynthesis was most significantly related to the UV-B response.Importantly,we found that the regulatory factor MYB4R1,which resides at the core of the network,has undergone neofunctionalization.In vitro and in vivo experiments demonstrated that MYB4R1 regulates flavonoid and anthocyanin accumulation in response to UV-B in buckwheat by binding to L-box motifs in the FtCHS,FtFLS,and FtUFGT promoters.We used deep learning to develop a visual discrimination model of buckwheat flavonoid content based on natural populations exposed to global UV-B radiation.Our study highlights the critical role of gene neofunctionalization in UV-B adaptation.
基金supported by the Science and Technology Development foundation of China Academy of Engineering Physics(Grant Nos.2015B0202041,2015B0202040)the Science and Technology Development foundation of China Academy of Engineering Physics(Grant 2015B0202040)+2 种基金the Science and Technology Development foundation of China Academy of Engineering Physics(Grant No.2015B0202033)for LiNSFC(Grant No.11371068)for SunNSFC(Grant No.11371068)for Zeng
文摘In this paper,we consider the multi-dimensional asymptotic preserving unified gas kinetic scheme for gray radiative transfer equations on distorted quadrilateral meshes.Different from the former scheme [J.Comput.Phys.285(2015),265-279] on uniform meshes,in this paper,in order to obtain the boundary fluxes based on the framework of unified gas kinetic scheme(UGKS),we use the real multi-dimensional reconstruction for the initial data and the macro-terms in the equation of the gray transfer equations.We can prove that the scheme is asymptotic preserving,and especially for the distorted quadrilateral meshes,a nine-point scheme [SIAM J.SCI.COMPUT.30(2008),1341-1361] for the diffusion limit equations is obtained,which is naturally reduced to standard five-point scheme for the orthogonal meshes.The numerical examples on distorted meshes are included to validate the current approach.
文摘The efficacy of ultraviolet(UV)disinfection has been analyzed and validated by numerous studies using culture-based methods,yet the discovery of the viable but nonculturable state necessitates the investigation of UV disinfection based on viability parameters.Paired regulators of the SOS response system,recA-lexA,and the programmed cell death system,mazEF,in Escherichia coli were chosen as the target genes,and the effect of UV irradiation on the mRNAs of the four genes was studied.This research showed that,after UV irradiation,the responses of the mRNAs were highly consistent,with reduction percentages of approximately 60% at 20 mJ/cm2,70% at 40 mJ/cm2,and 90% at 80 mJ/cm2,and these reductions were believed to be the result of direct UV damage to nucleic acids.After 24 h of dark incubation,recA and lexA were both upregulated but to a lesser extent for repressor lexA;and mazE and mazF were both downregulated.This result implies that UV irradiation induces the dark repair system more actively,and the cells will proceed to death at a rate similar to that associated with natural decay.