Developing a cost-effective and environmentally friendly process for the production of valuable chemicals from abundant herbal biomass receives great attentions in recent years.Herein,taking advantage of the“lignin f...Developing a cost-effective and environmentally friendly process for the production of valuable chemicals from abundant herbal biomass receives great attentions in recent years.Herein,taking advantage of the“lignin first”strategy,corn straw is converted to valuable chemicals including lignin monomers,furfural and 5-methoxymethylfurfural via a two steps process.The key of this research lies in the development of a green and low-cost catalytic process utilizing magnetic Raney Ni catalyst and high boiling point ethylene glycol.The utilization of neat ethylene glycol as the sole slovent under atmospheric conditions obviates the need for additional additives,thereby facilitating the entire process to be conducted in glass flasks and rendering it highly convenient for scaling up.In the initial step,depolymerization of corn straw lignin resulted in a monomer yield of 18.1 wt%.Subsequently,in a dimethyl carbonate system,the carbohydrate component underwent complete conversion in a one-pot process,yielding furfural and 5-methoxymethylfurfural as the primary products with an impressive yield of 47.7%.展开更多
Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some sho...Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some shortcomings because of the low permeability and tightness of shale,complex gas flow behavior of multi-scale gas transport regions and multiple gas transport mechanism superpositions,and complex and variable production regimes of shale gas wells.Recent research has demonstrated the existence of a multi-stage isotope fractionation phenomenon during shale gas production,with the fractionation characteristics of each stage associated with the pore structure,gas in place(GIP),adsorption/desorption,and gas production process.This study presents a new approach for estimating shale gas well production and evaluating the adsorbed/free gas ratio throughout production using isotope fractionation techniques.A reservoir-scale carbon isotope fractionation(CIF)model applicable to the production process of shale gas wells was developed for the first time in this research.In contrast to the traditional model,this model improves production prediction accuracy by simultaneously fitting the gas production rate and δ^(13)C_(1) data and provides a new evaluation method of the adsorbed/free gas ratio during shale gas production.The results indicate that the diffusion and adsorption/desorption properties of rock,bottom-hole flowing pressure(BHP)of gas well,and multi-scale gas transport regions of the reservoir all affect isotope fractionation,with the diffusion and adsorption/desorption parameters of rock having the greatest effect on isotope fractionation being D∗/D,PL,VL,α,and others in that order.We effectively tested the universality of the four-stage isotope fractionation feature and revealed a unique isotope fractionation mechanism caused by the superimposed coupling of multi-scale gas transport regions during shale gas well production.Finally,we applied the established CIF model to a shale gas well in the Sichuan Basin,China,and calculated the estimated ultimate recovery(EUR)of the well to be 3.33×10^(8) m^(3);the adsorbed gas ratio during shale gas production was 1.65%,10.03%,and 23.44%in the first,fifth,and tenth years,respectively.The findings are significant for understanding the isotope fractionation mechanism during natural gas transport in complex systems and for formulating and optimizing unconventional natural gas development strategies.展开更多
Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not y...Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not yet fully understood.In this study,the V(V)reduction mechanisms with concomitant V isotope fractionation by the Gram-positive bacterium Bacillus subtilis(B.subtilis)and the Gramnegative bacterium Thauera humireducens(T.humireducens)were investigated.Both strains could effectively reduce V(V),removing(90.5%±1.6%)and(93.0%±1.8%)of V(V)respectively from an initial concentration of 50 mg L^(-1) during a 10-day incubation period.V(V)was bioreduced to insoluble vanadium(IV),which was distributed both inside and outside the cells.Electron transfer via cytochrome C,nicotinamide adenine dinucleotide,and glutathione played critical roles in V(V)reduction.Metabolomic analysis showed that differentially enriched metabolites(quinone,biotin,and riboflavin)mediated electron transfer in both strains.The aqueous V in the remaining solution became isotopically heavier as V(V)bioreduction proceeded.The obtained V isotope composition dynamics followed a Rayleigh fractionation model,and the isotope enrichment factor(e)was(–0.54‰±0.04‰)for B.subtilis and(–0.32‰±0.03‰)for T.humireducens,with an insignificant difference.This study provides molecular insights into electron transfer for V(V)bioreduction and reveals V isotope fractionation during this bioprocess,which is helpful for understanding V biogeochemistry and developing novel strategies for V remediation.展开更多
Stable Sr isotopic composition(δ^(88/86)Sr)can be used to study magmatic processes,but their fractionation mechanism during magmatic evolution remains unclear.To understand the fractionation behaviors of the stable S...Stable Sr isotopic composition(δ^(88/86)Sr)can be used to study magmatic processes,but their fractionation mechanism during magmatic evolution remains unclear.To understand the fractionation behaviors of the stable Sr isotopes during magmatism,we report theδ^(88/86)Sr values of the Huili granitic pluton,which was subjected to intensive crystal-melt separation.The Huili pluton consists of K-feldspar granite and more evolved albite granite,and the albite granite exhibits significantly higherδ^(88/86)Sr values(+0.36‰to+0.52‰)than that of K-feldspar granite(+0.11‰to+0.25‰).K-feldspar,which contributes most of the Sr budget of the K-feldspar granite,has slightly lowerδ^(88/86)Sr values(−0.01‰to+0.17‰)than the whole rock.Theδ^(88/86)Sr variation of the Huili granites can be explained by separation of melt from K-feldspar-dominated crystals,because crystallization of K-feldspar can result in heavy Sr isotopic composition of the extracted interstitial melt.Stable Sr and Ba isotopic ratios in the Huili granites are highly coupled toward the heavy direction,refl ecting their similar element partitioning and isotope fractionation behaviors between the crystalline K-feldspar and melt.This study indicates that melt extraction plays a key role in granitic magma evolution.展开更多
Carbon isotope fractionation served as a key geochemical indicator for understanding shale gas storage and migration.However,the detailed mechanism of the fractionation behaviors of methane isotopes(^(12)CH_(4)/^(13)C...Carbon isotope fractionation served as a key geochemical indicator for understanding shale gas storage and migration.However,the detailed mechanism of the fractionation behaviors of methane isotopes(^(12)CH_(4)/^(13)CH_(4))was still limited,especially under two-phase flow.This study employed molecular dynamics(MD)simulations to investigate water-mediated nonlinear isotope transport in 3 nm hydrophilic silica nanopores,highlighting gas-liquid-solid interfacial effects on fractionation mechanisms.Simulations of different water saturation(0%-44.66%)showed a critical hydration threshold of 30.44%at a pressure gradient of 20 MPa.Below this threshold,continuous water film formed on pore walls,which transformed the gas transport from surface diffusion to viscous flow through gas-liquid interactions,while hydrogen bonds in the water film weakened gas-solid slip effects.However,when water saturation exceeded 30.44%,the formation of water bridges blocked the mobility of isotopic gases.The water film reduced the depth of solid-gas potential wells,leading to diminished adsorption capacity for isotopic gases,and lowered the surface roughness of pore walls(as characterized by potential energy surface,PES).Additionally,the water film enhanced the Knudsen diffusion effect of isotope gases due to the decrease in effective pore size.As a result,the formation of water film intensified methane isotopic fractionation,which was manifested as a decrease in the^(13)CH_(4)/^(12)CH_(4)diffusion coefficient ratio(D∗/D)from 0.975 to 0.942 and an increase in isotopic enthalpy differences(Δh_(^(12)C)_^(13)C) from 0.105 to 1.139 J/m^(3).Furthermore,in the gas-liquid-solid interfacial system,an elevated pressure differential modified the relative motion velocities among the methane-water-pore surface,resulting a non-monotonic isotopic fractionation trend(initial increase followed by decrease).These findings provided molecular-level insights into the complex isotopic fractionation in shale gas systems.展开更多
Water-soluble organic matter(WSOM)significantly influences the transport of metals and organic contaminants in soils,yet the interaction specifics with antimony(Sb)remain largely unexplored.Antimony is of particular e...Water-soluble organic matter(WSOM)significantly influences the transport of metals and organic contaminants in soils,yet the interaction specifics with antimony(Sb)remain largely unexplored.Antimony is of particular environmental concern due to its toxic properties and harmful effects on ecosystems and human health.Employing a three-step fractionation method with polyvinylpyrrolidone(PVP),this study aimed to isolate and analyze humic acids(HA),PVP-non adsorbed fulvic acids(FAA),and PVP-adsorbed fulvic acids(FAB)from WSOM in soil spiked with Sb and incubated for 18 months.These fractions underwent chemical analysis for carbon(C),nitrogen(N),total organic carbon(TOC),and Sb,complemented by FTIR and 1H NMR spectroscopic characterization.The study revealed that HA wasmore aliphatic,with Sb predominantly associating with the fulvic acid(FA)fraction,accounting for 97%of Sb in extracts.Specifically,the FAA subfraction held substantial portions of total carbon(TC),total nitrogen(TN),total organic carbon(TOC),and Sb.Correlations between Sb concentrations and TN,TC,and TOC were significant.Extraction methods showed NaOH and Na_(4)P_(2)O_(7) outperformed HCl and deionised water in extracting TC,TN,and TOC,with higher Sb concentrations found in Na_(4)P_(2)O_(7) and NaOH extracts.This underscores the role of Fe/Al-SOM complexes in Sb soil availability.The results revealed that FAA subfraction accounted for 76%,64%and 94%of TN,TOC and Sb,respectively.Therefore,this research highlights the FAA fraction’s central role,predominantly comprising non-humic substances like amines,in the availability of C,N,and Sb in Sb-impacted soils.The findings offer insights for environmental management and remediation strategies.展开更多
Taking deep coal-rock gas in the Yulin and Daning-Jixian areas of the Ordos Basin,NW China,as the research object,full-diameter coal rock samples with different cleat/fracture development degrees from the Carboniferou...Taking deep coal-rock gas in the Yulin and Daning-Jixian areas of the Ordos Basin,NW China,as the research object,full-diameter coal rock samples with different cleat/fracture development degrees from the Carboniferous Benxi Formation were selected to conduct physical simulation and isotope monitoring experiments of the full-life-cycle depletion development of coal-rock gas.Based on the experimental results,a dual-medium carbon isotope fractionation(CIF)model coupling cleats/fractures and matrix pores was constructed,and an evaluation method for free gas production patterns was established to elucidate the carbon isotope fractionation mechanism and adsorbed/free gas production characteristics during deep coal-rock gas development.The results show that the deep coal-rock gas development process exhibits a three-stage carbon isotope fractionation pattern:“Stable(Ⅰ)→Decrease(Ⅱ)→Increase(Ⅲ)”.A rapid decline in boundary pressure in stageⅢleads to fluctuations in isotope value,characterized by a“rapid decrease followed by continued increase”,with free gas being produced first and long-term supply of adsorbed gas.The CIF model can effectively match measured gas pressure,cumulative gas production,and δ^(13)C_(1) value of produced gas.During the first two stages of isotope fractionation,free gas dominated cumulative production.During the mid-late stages of slow depletion production,the staged pressure control development method can effectively increase the gas recovery.The production of adsorbed gas is primarily controlled by the rock's adsorption capacity and the presence of secondary flow channels.Effectively enhancing the recovery of adsorbed gas during the late stage remains crucial for maintaining stable production and improving the ultimate recovery factor of deep coal-rock gas.展开更多
Based on geochemical data from natural gas samples across spring water systems and sedimentary basins,including Songliao,Bohai Bay,Sanshui,Sichuan,Ordos,Tarim and Ying-Qiong,this paper systematically compares the geoc...Based on geochemical data from natural gas samples across spring water systems and sedimentary basins,including Songliao,Bohai Bay,Sanshui,Sichuan,Ordos,Tarim and Ying-Qiong,this paper systematically compares the geochemical compositions of abiogenic versus biogenic gases.Emphasis is placed on the diagnostic signatures of abiogenic gases in terms of gas composition,and carbon,hydrogen and helium isotopes.The main findings are as follows.(1)In hydrothermal spring systems,abiogenic alkane gases are extremely scarce.Methane concentrations are typically less than 1%,with almost no detectable C^(2+)hydrocarbons.The gas is dominantly composed of CO_(2),while N_(2)is the major component in a few samples.(2)Abiogenic alkane gases display distinct isotopic signatures,including enriched methane carbon isotopic compositions(δ^(13)C_(1)>-25‰generally),complete carbon isotopic reversal(δ^(13)C_(1)>δ^(13)C_(2)>δ^(13)C_(3)>δ^(13)C_(4)),and enriched helium isotope(R/Ra>0.5,CH_(4)/^(3)He≤10^(6)generally).(3)The hydrogen isotopic composition of abiogenic alkane gases may be characterized by a positive sequence(δD_(1)<δD_(2)<δD_(3)),or a complete reversal(δD_(1)>δD_(2)>δD_(3)),or a V-shaped distribution(δD_(1)>δD_(2),δD_(2)<δD_(3)).The hydrogen isotopic compositions of methane generally show limited variation(about 9‰),possibly due to hydrogen isotopic exchange with connate water.(4)In terms of identifying gas origin,CH_(4)/^(3)He-R/Ra andδ^(13)CCO_(2)-R/Ra charts are more effective than CO_(2)/^(3)He-R/Ra chart.These new geological insights provide theoretical clues and diagnostic charts for the genetic identification of natural gas and further research on abiogenic gases.展开更多
Lassa Fever(LF)is a viral hemorrhagic illness transmitted via rodents and is endemic in West Africa,causing thousands of deaths annually.This study develops a dynamic model of Lassa virus transmission,capturing the pr...Lassa Fever(LF)is a viral hemorrhagic illness transmitted via rodents and is endemic in West Africa,causing thousands of deaths annually.This study develops a dynamic model of Lassa virus transmission,capturing the progression of the disease through susceptible,exposed,infected,and recovered populations.The focus is on simulating this model using the fractional Caputo derivative,allowing both qualitative and quantitative analyses of boundedness,positivity,and solution uniqueness.Fixed-point theory and Lipschitz conditions are employed to confirm the existence and uniqueness of solutions,while Lyapunov functions establish the global stability of both disease-free and endemic equilibria.The study further examines the role of the Caputo operator by solving the generalized power-law kernel via a two-step Lagrange polynomial method.This approach offers practical advantages in handling additional data points in integral forms,though Newton polynomial-based schemes are generally more accurate and can outperform Lagrange-based Adams-Bashforth methods.Graphical simulations validate the proposed numerical approach for different fractional orders(ν)and illustrate the influence of model parameters on disease dynamics.Results indicate that increasing the fractional order accelerates the decline of Lassa fever in both human and rodent populations.Moreover,fractional-order modeling provides more nuanced insights than traditional integer-order models,suggesting potential improvements for medical intervention strategies.The study demonstrates that carefully chosen fractional orders can optimize convergence and enhance the predictive capacity of Lassa fever models,offering a promising direction for future research in epidemiological modeling.展开更多
Background There is still limited data on predictive value of coronary computed tomography angiography(CCTA)–derived fractional flow reserve(CT-FFR) for long term outcomes. We examined the long-term prognostic value ...Background There is still limited data on predictive value of coronary computed tomography angiography(CCTA)–derived fractional flow reserve(CT-FFR) for long term outcomes. We examined the long-term prognostic value of CT-FFR combined with CCTA–defined atherosclerotic extent in diabetic patients with coronary artery disease(CAD).Methods A retrospective pooled analysis of individual patient data was performed. Deep-learning-based vessel-specific CTFFR was calculated. All patients enrolled were followed-up for at least 5 years. Predictive abilities for major adverse cardiac events(MACE) were compared among three models(model 1), constructed using clinical variables;model 2, model 1+CCTA–derived atherosclerotic extent(Leiden risk score);and model 3, model 2+CT-FFR.Results A total of 480 diabetic patients [median age, 61(55–66) years;52.9% men] were included. During a median follow-up time of 2197(2126–2355) days, 55 patients(11.5%) experienced MACE. In multivariate-adjusted Cox models, Leiden risk score(HR: 1.06;95% CI: 1.01–1.11;P = 0.013) and CT-FFR ≤ 0.80(HR: 6.54;95% CI: 3.18–13.45;P < 0.001) were the independent predictors. The discriminant ability was higher in model 2 than in model 1(C-index, 0.75 vs. 0.63;P < 0.001) and was further promoted by adding CT-FFR to model 3(C-index, 0.81 vs. 0.75;P = 0.002). Net reclassification improvement(NRI) was 0.19(P = 0.009) for model 2 beyond model 1. Of note, adding CT-FFR to model 3 also exhibited significantly improved reclassification compared with model 2(NRI = 0.14;P = 0.011).Conclusion In diabetic patients with CAD, CT-FFR provides robust and incremental prognostic information for predicting longterm outcomes. The combined model exhibits improved prediction abilities, which is beneficial for risk stratification.展开更多
Insight into the carbon turnover in soil aggregates and density fractions is essential for reducing the uncertainty in estimating carbon pools on the Tibetan Plateau,and how they vary with land use type is unclear.In ...Insight into the carbon turnover in soil aggregates and density fractions is essential for reducing the uncertainty in estimating carbon pools on the Tibetan Plateau,and how they vary with land use type is unclear.In this study,the effect of land use type on carbon storage and fractionation was quantified based on organic carbon and its ^(13)C abundance at the microscale of soil aggregates and density fractions in Tibetan alpine ecosystems.The sequence of soil aggregate destruction in the land use types of plantation(13.1%)<shrubland(32.7%)<grassland(47.9%)<farmland(61.8%)shows that plantations strengthen the soil structure.Plantation land had a greater contribution of light fraction organic carbon(28.3%)but a lower contribution of mineral-associated organic carbon(40.6%)to the carbon stock compared to farmland(13.5 and 70.3%).Interestingly,plantation land enhanced the aggregational differentiation of organic carbon and ^(13)C in each density fraction,whereas no such phenomenon existed in the soil organic carbon.Carbon isotope analyses revealed that carbon transfer in the plantation land occurred from the light fraction in macroaggregates(–24.9‰)to the mineral-associated fraction in microaggregates(–19.9‰).When compared to the other three land use types,the low transferability of carbon in aggregates and density fractions in plantation land provides a stable carbon pool for the Tibetan Plateau.This study shows that plantations can mitigate global climate change by slowing carbon transfer and increasing carbon storage at the microscale of aggregates and density fractions in alpine regions.展开更多
Grifola frondosa(Maitake)is traditionally valued for its health benefits,with polysaccharides being key bioactive components.This paper investigates a specific subfraction,Fraction D(GFP-D),evaluating its clinical eff...Grifola frondosa(Maitake)is traditionally valued for its health benefits,with polysaccharides being key bioactive components.This paper investigates a specific subfraction,Fraction D(GFP-D),evaluating its clinical effects and mechanisms in immune enhancement,adjunctive anti-tumor activity,and regulation of glucose/lipid metabolism.Three clinical trials were conducted.In an immune study,120 healthy volunteers(CD4+T cell count 500–1000 cells/μL)received 150 mg/day GFP-D for 8 weeks,resulting in significant increases in CD4+T cells(from 632±95 to 812±108 cells/μL,28.5%increase,within the physiological activation range),CD4+/CD8+ratio,NK cell activity,IL-2,and IFN-γ(all P<0.001 vs.placebo).An anti-tumor study with 80 advanced cancer patients(stratified by age,tumor stage,and histotype)showed that adding 1000 mg/day GFP-D to chemotherapy improved objective response rate(52.5%vs.30.0%,P=0.036,95%CI:1.02–3.87),one-year progression-free survival(55.8%vs.33.3%,P=0.022),and preserved immune parameters versus chemotherapy alone.A metabolic study in 90 type 2 diabetes patients found that 400 mg/day GFP-D for 12 weeks significantly lowered fasting glucose,HbA1c,total cholesterol,triglycerides,and LDL-C,while raising HDL-C(from 1.0±0.2 to 1.2±0.2 mmol/L,20%increase,supported by increased AMPK phosphorylation).Mechanistically,immune enhancement involves macrophage/dendritic cell activation via Dectin-1/TLR4 receptors(confirmed by increased receptor expression and downstream signaling molecules),promoting cytokine-driven T/NK cell responses.Anti-tumor effects stem from immunomodulation,direct induction of cancer cell apoptosis(via mitochondrial/caspase pathways,verified by increased Bax/Bcl-2 ratio and caspase-3 activation),and angiogenesis inhibition by downregulating VEGF.Metabolic benefits are linked to AMPK pathway activation in liver/muscle(confirmed by increased p-AMPK/AMPK ratio),enhancing glucose uptake and inhibiting gluconeogenesis/lipogenesis,alongside modulation of gut microbiota(increased Bifidobacterium and Lactobacillus abundance).All trials reported no severe adverse events related to GFP-D;liver/kidney function parameters(ALT,AST,creatinine,urea nitrogen)remained within normal ranges throughout the intervention.Collectively,GFP-D emerges as a multi-functional bioactive agent with substantial therapeutic potential.展开更多
In this paper,we first give a sufficient condition for a graph being fractional ID-[a,b]-factor-critical covered in terms of its independence number and minimum degree,which partially answers the problem posed by Sizh...In this paper,we first give a sufficient condition for a graph being fractional ID-[a,b]-factor-critical covered in terms of its independence number and minimum degree,which partially answers the problem posed by Sizhong Zhou,Hongxia Liu and Yang Xu(2022).Then,an A_(α)-spectral condition is given to ensure that G is a fractional ID-[a,b]-factor-critical covered graph and an(a,b,k)-factor-critical graph,respectively.In fact,(a,b,k)-factor-critical graph is a graph which has an[a,b]-factor for k=0.Thus,these above results extend the results of Jia Wei and Shenggui Zhang(2023)and Ao Fan,Ruifang Liu and Guoyan Ao(2023)in some sense.展开更多
[Objective] This study aimed to promote the combination of cultivation and livestock farming, and to explore an environment-protecting farming style. [Method]The effects of anaerobically fermented complete compound so...[Objective] This study aimed to promote the combination of cultivation and livestock farming, and to explore an environment-protecting farming style. [Method]The effects of anaerobically fermented complete compound sow feed, added with Lactobacillus and Bacillus subtilis, on the chemical fractionation of copper, iron, zinc and manganese in feed and pig manure and skatole content in pig manure were investigated. [Result] Compared with those in the non-fermented feed, in the fermented feed and pig manure, the acetic acid-extractable copper, iron, zinc and manganese contents increased significantly（P0.05）, the reduced copper and iron contents increased significantly（P 0.05）, the oxidized copper and iron contents reduced significantly（P0.05）, and the residual copper contents remained unchangeable（P0.05）. The pH value of fermented feed decreased significantly（P0.05）, and that of pig manure increased significantly（P0.05）. The skatole content in pig manure decreased significantly（P 0.01）. The Lactobacillus abundance and amylase and cellulase activity increased significantly（P 0.05）. [Conclusion] The fermentation of feed changed the chemical fractionation of copper, iron, zinc and manganese in feed and pig manure, and reduced the manure odor.展开更多
Typical sediments from Taihu Lake, a meso-to-hypereutrophic lake, were collected and examined on the basis of P-fractionation by sequential extraction scheme. Sedimentary inorganic phosphorus were fractioned into four...Typical sediments from Taihu Lake, a meso-to-hypereutrophic lake, were collected and examined on the basis of P-fractionation by sequential extraction scheme. Sedimentary inorganic phosphorus were fractioned into four forms and the rank order according to the mean concentration of P-fractions in Taihu Lake was NaOH-P>BD-P>HCl-P>NH_4Cl-P. The concentrations of BD-P were linearly correlated with the content of active Fe(R2=0.96). Also, the linear relationship between the sum of BD-P and NaOH-P and the sum of active Fe and active Al content was observed within the six sediments investigated(R2=0.96). Moreover, the bio-available phosphorus(BAP) content was estimated by the sum of NH_4Cl-P, BD-P, and NaOH-P, viz. BAP=NH_4Cl-P+NaOH-P+BD-P. In Taihu Lake, the BAP contents are ranging from 0.10 mg/g dw to 1.25 mg/g dw, and average 0.40 mg/g dw for all sediment samples. The relative contributions of BAP to total sedimentary phosphorus(TP) and inorganic sedimentary phosphorus(IP) range from 18.67% to 50.79%(33.61% on average) and from 52.82% to 82.09%(67.81% on average), respectively.展开更多
REE fractionation during the weathering of dolomite has been recognized for decades.A regolith profile on dolomite in southwest Yunnan of China was selected to investigate the behaviors of REE during weathering.The we...REE fractionation during the weathering of dolomite has been recognized for decades.A regolith profile on dolomite in southwest Yunnan of China was selected to investigate the behaviors of REE during weathering.The weathering of dolomite is divided into two stages：the pedogenesis stage and soil evolution stage,corresponding to the saprolites and soils respectively in the regolith profile. SiO_2,TiO_2,P_2O_5,Zr,Hf,Nb and Ta were immobile components during the weathering by and large, while Al_2O_3,K_2O and Fe_2O_3 were lost during the soil evolution stage in the physical form（clay minerals probably）.REE were fractionated during the whole weathering of dolomite.The field weathering profile and the lab acid-leaching experiments on dolomite indicate that MREE were enriched clearly relative to other REE during the pedogenesis stage in a ＂capillary ascending-adsorption＂ mechanism, but they did not fractionate clearly in the soil evolution stage.REE were lost and accumulated in the weathering front of dolomite during the soil evolution stage in a ＂physical-chemical leaching＂ mechanism.展开更多
Studies were carried out on several aspects of rare earth elements （REEs）, such as the theory and practice of their applications in agriculture, their geochemical behaviors in natural and agricultural ecosystems, th...Studies were carried out on several aspects of rare earth elements （REEs）, such as the theory and practice of their applications in agriculture, their geochemical behaviors in natural and agricultural ecosystems, the mechanisms for the increase of crop yield using REE fertilizer, and their toxicology. However, limited knowledge was available for the transfer processes and the features and mechanisms of distribution and fractionations of REEs inside plants. The characteristics of REE fractionations in plants can be used to ＂trace＂ the pathway of REE transportation from soils （solution） to plants. A better understanding of the mechanisms of REE fractionations was helpful to investigate the controlling factors, including both the internal and the external ones. The characteristics and mechanisms of REE fractionations in plants and their significance were reviewed. Furthermore, the prospect for these fields was discussed, in hope of providing a new way in studying the bioavailability of REEs and heavy metals.展开更多
^ 15N isotope tracer techniques and ecological modeling were adopted to investigate the fractionation of nitrogen, its uptake and transformation in algae and snail （Bellamya aeruginosa Reeve）. Different algal specie...^ 15N isotope tracer techniques and ecological modeling were adopted to investigate the fractionation of nitrogen, its uptake and transformation in algae and snail （Bellamya aeruginosa Reeve）. Different algal species were found to differ in their uptake of nitrogen isotopes. Microcystis aeruginisa Ktitz. demonstrated the greatest ^15N accumulation capacity, with the natural variation in isotopic ratio （δ^15N） and the isotope fractionation factor （ε,‰） being the highest among the species investigated. The transformation and utilization of ^15N by snails differed depending on the specific algae consumed （highest for Chlorella pyrenoidosa Chick., lowest for M. aeruginisa）. When snails was seeded in the experimental pond, the algae population structure changed significantly, and total algal biomass as well as the concentration of all nitrogen species decreased, causing an increase in water transparency. A model, incorporating several chemical and biological parameters, was developed to predict algal biomass in an aquatic system when snails was present. The data collected during this investigation indicated that the gastropods such as snails could significantly impact biological community and water quality of small water bodies, suggesting a role for biological control of noxious algal blooms associated with eutrophication.展开更多
In most arid and semiarid soils, naturally occurring phosphorus(P) is a major yield-limiting plant nutrient. In this study, to investigate the effects of organic(OP) and inorganic P(IP) sources on P fractionation, a c...In most arid and semiarid soils, naturally occurring phosphorus(P) is a major yield-limiting plant nutrient. In this study, to investigate the effects of organic(OP) and inorganic P(IP) sources on P fractionation, a calcareous sandy loam alkaline soil was fertilized with OP and IP fertilizers at low(80 mg P kg^(-1) soil) and high(160 mg P kg^(-1) soil) application rates. Three combinations of OP and IP(i.e., 75% OP + 25% IP, 50% OP + 50% IP, and 25% OP + 75% IP) were applied at low and high application rates,respectively, followed by soil aging for 21 d. Soil samples were collected after 1, 2, 3, 7, and 21 d and subjected to sequential extraction to analyze soluble and exchangeable, Fe-and Al-bound, Ca-bound, and residual P fractions. The soluble and exchangeable P fraction significantly increased up to 24.3%, whereas the Ca-bound fraction decreased up to 40.7% in the soils receiving 75% OP + 25% IP and 50% OP + 50% IP, respectively, compared with the control(receiving no P fertilizer). However, the transformation of P fractions was influenced by aging time. Addition of P sources caused instant changes in different P fractions, which then tended to decline with aging time. Change in soil p H was the limiting factor in controlling P availability. At high application rate, the OP source significantly increased soil P availability compared with the IP source with soil aging. Depending on P fractionation, a proper combination of OP and IP fertilizers, as long-term slow and instant P-releasing sources for plant uptake, respectively, may be a sustainable strategy to meet crop P requirements in the arid and semiarid soils.展开更多
The distribution characteristics of phosphorus （P） forms in the sediment profile of Lake Erhai, in southwestern China has been investigated by sequential extraction and 31p nuclear magnetic resonance spectroscopy （...The distribution characteristics of phosphorus （P） forms in the sediment profile of Lake Erhai, in southwestern China has been investigated by sequential extraction and 31p nuclear magnetic resonance spectroscopy （NMR） of NaOH extracts to understand P dynamics and its potential contribution to lake eutrophication. Contents of P fractions varied in the order of NH4C1 extracted P （NH4C1- P） 〈 bicarbonate-dithionite extracted P （BD-P） 〈 HC1-P, Residual-P 〈 NaOH extracted P （NaOH-P）. The highly available NH4C1-P represented less than 1% of total P （TP）. BD-P and NaOH extracted reactive P （NaOH-rP） averaged 39%, while the ratio of Fe/P was higher than 15, indicating low P release from the sediments under permanent oxic condition. The less bio-available HC1-P, NaOH extracted nonreactive P （NaOH-nrP） and residual-P contributed 61% of TP. Regression analysis revealed that BD-P, NaOH-rP and HC1-P were positively correlated with the contents of Fe and Mn, A1 and Fe, and Ca, respectively. The investigation of P compound groups in NaOH extracts by 31p NMR showed that ortho-P and monoester-P were the largest two constituents of the P pool, followed by diester-P, phosphonate and pyro-P. A comparison of vertical variations of P groups in the sediment profile suggested that these compounds were involved in the P recycling to different extents in Lake Erhai. In particular, the lake exhibits high potential for labile P release from the surface sediments, which should be taken into consideration even after the outsourced P runoff ceased.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(QNTD202302)National Natural Science Foundation of China(22378024)the Foreign expert program(G2022109001L).
文摘Developing a cost-effective and environmentally friendly process for the production of valuable chemicals from abundant herbal biomass receives great attentions in recent years.Herein,taking advantage of the“lignin first”strategy,corn straw is converted to valuable chemicals including lignin monomers,furfural and 5-methoxymethylfurfural via a two steps process.The key of this research lies in the development of a green and low-cost catalytic process utilizing magnetic Raney Ni catalyst and high boiling point ethylene glycol.The utilization of neat ethylene glycol as the sole slovent under atmospheric conditions obviates the need for additional additives,thereby facilitating the entire process to be conducted in glass flasks and rendering it highly convenient for scaling up.In the initial step,depolymerization of corn straw lignin resulted in a monomer yield of 18.1 wt%.Subsequently,in a dimethyl carbonate system,the carbohydrate component underwent complete conversion in a one-pot process,yielding furfural and 5-methoxymethylfurfural as the primary products with an impressive yield of 47.7%.
基金supported by the Natural Science Foundation of China(Grant No.42302170)National Postdoctoral Innovative Talent Support Program(Grant No.BX20220062)+3 种基金CNPC Innovation Found(Grant No.2022DQ02-0104)National Science Foundation of Heilongjiang Province of China(Grant No.YQ2023D001)Postdoctoral Science Foundation of Heilongjiang Province of China(Grant No.LBH-Z22091)the Natural Science Foundation of Shandong Province(Grant No.ZR2022YQ30).
文摘Prediction of production decline and evaluation of the adsorbed/free gas ratio are critical for determining the lifespan and production status of shale gas wells.Traditional production prediction methods have some shortcomings because of the low permeability and tightness of shale,complex gas flow behavior of multi-scale gas transport regions and multiple gas transport mechanism superpositions,and complex and variable production regimes of shale gas wells.Recent research has demonstrated the existence of a multi-stage isotope fractionation phenomenon during shale gas production,with the fractionation characteristics of each stage associated with the pore structure,gas in place(GIP),adsorption/desorption,and gas production process.This study presents a new approach for estimating shale gas well production and evaluating the adsorbed/free gas ratio throughout production using isotope fractionation techniques.A reservoir-scale carbon isotope fractionation(CIF)model applicable to the production process of shale gas wells was developed for the first time in this research.In contrast to the traditional model,this model improves production prediction accuracy by simultaneously fitting the gas production rate and δ^(13)C_(1) data and provides a new evaluation method of the adsorbed/free gas ratio during shale gas production.The results indicate that the diffusion and adsorption/desorption properties of rock,bottom-hole flowing pressure(BHP)of gas well,and multi-scale gas transport regions of the reservoir all affect isotope fractionation,with the diffusion and adsorption/desorption parameters of rock having the greatest effect on isotope fractionation being D∗/D,PL,VL,α,and others in that order.We effectively tested the universality of the four-stage isotope fractionation feature and revealed a unique isotope fractionation mechanism caused by the superimposed coupling of multi-scale gas transport regions during shale gas well production.Finally,we applied the established CIF model to a shale gas well in the Sichuan Basin,China,and calculated the estimated ultimate recovery(EUR)of the well to be 3.33×10^(8) m^(3);the adsorbed gas ratio during shale gas production was 1.65%,10.03%,and 23.44%in the first,fifth,and tenth years,respectively.The findings are significant for understanding the isotope fractionation mechanism during natural gas transport in complex systems and for formulating and optimizing unconventional natural gas development strategies.
基金supported by the National Natural Science Foundation of China(U21A2033)the Fundamental Research Funds for the Central Universities(2652022103).
文摘Microbial vanadate(V(V))reduction is a key process for environmental geochemistry and detoxification of vanadium(V).However,the electron transfer pathways and V isotope fractionation involved in this process are not yet fully understood.In this study,the V(V)reduction mechanisms with concomitant V isotope fractionation by the Gram-positive bacterium Bacillus subtilis(B.subtilis)and the Gramnegative bacterium Thauera humireducens(T.humireducens)were investigated.Both strains could effectively reduce V(V),removing(90.5%±1.6%)and(93.0%±1.8%)of V(V)respectively from an initial concentration of 50 mg L^(-1) during a 10-day incubation period.V(V)was bioreduced to insoluble vanadium(IV),which was distributed both inside and outside the cells.Electron transfer via cytochrome C,nicotinamide adenine dinucleotide,and glutathione played critical roles in V(V)reduction.Metabolomic analysis showed that differentially enriched metabolites(quinone,biotin,and riboflavin)mediated electron transfer in both strains.The aqueous V in the remaining solution became isotopically heavier as V(V)bioreduction proceeded.The obtained V isotope composition dynamics followed a Rayleigh fractionation model,and the isotope enrichment factor(e)was(–0.54‰±0.04‰)for B.subtilis and(–0.32‰±0.03‰)for T.humireducens,with an insignificant difference.This study provides molecular insights into electron transfer for V(V)bioreduction and reveals V isotope fractionation during this bioprocess,which is helpful for understanding V biogeochemistry and developing novel strategies for V remediation.
基金supported by National Natural Science Foundation of China(42473009).
文摘Stable Sr isotopic composition(δ^(88/86)Sr)can be used to study magmatic processes,but their fractionation mechanism during magmatic evolution remains unclear.To understand the fractionation behaviors of the stable Sr isotopes during magmatism,we report theδ^(88/86)Sr values of the Huili granitic pluton,which was subjected to intensive crystal-melt separation.The Huili pluton consists of K-feldspar granite and more evolved albite granite,and the albite granite exhibits significantly higherδ^(88/86)Sr values(+0.36‰to+0.52‰)than that of K-feldspar granite(+0.11‰to+0.25‰).K-feldspar,which contributes most of the Sr budget of the K-feldspar granite,has slightly lowerδ^(88/86)Sr values(−0.01‰to+0.17‰)than the whole rock.Theδ^(88/86)Sr variation of the Huili granites can be explained by separation of melt from K-feldspar-dominated crystals,because crystallization of K-feldspar can result in heavy Sr isotopic composition of the extracted interstitial melt.Stable Sr and Ba isotopic ratios in the Huili granites are highly coupled toward the heavy direction,refl ecting their similar element partitioning and isotope fractionation behaviors between the crystalline K-feldspar and melt.This study indicates that melt extraction plays a key role in granitic magma evolution.
基金support from the National Natural Science Foundation of China,China(Grant 51776132)the Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process of the Ministry of Education(China University of Mining and Technology)(No.2024-007).
文摘Carbon isotope fractionation served as a key geochemical indicator for understanding shale gas storage and migration.However,the detailed mechanism of the fractionation behaviors of methane isotopes(^(12)CH_(4)/^(13)CH_(4))was still limited,especially under two-phase flow.This study employed molecular dynamics(MD)simulations to investigate water-mediated nonlinear isotope transport in 3 nm hydrophilic silica nanopores,highlighting gas-liquid-solid interfacial effects on fractionation mechanisms.Simulations of different water saturation(0%-44.66%)showed a critical hydration threshold of 30.44%at a pressure gradient of 20 MPa.Below this threshold,continuous water film formed on pore walls,which transformed the gas transport from surface diffusion to viscous flow through gas-liquid interactions,while hydrogen bonds in the water film weakened gas-solid slip effects.However,when water saturation exceeded 30.44%,the formation of water bridges blocked the mobility of isotopic gases.The water film reduced the depth of solid-gas potential wells,leading to diminished adsorption capacity for isotopic gases,and lowered the surface roughness of pore walls(as characterized by potential energy surface,PES).Additionally,the water film enhanced the Knudsen diffusion effect of isotope gases due to the decrease in effective pore size.As a result,the formation of water film intensified methane isotopic fractionation,which was manifested as a decrease in the^(13)CH_(4)/^(12)CH_(4)diffusion coefficient ratio(D∗/D)from 0.975 to 0.942 and an increase in isotopic enthalpy differences(Δh_(^(12)C)_^(13)C) from 0.105 to 1.139 J/m^(3).Furthermore,in the gas-liquid-solid interfacial system,an elevated pressure differential modified the relative motion velocities among the methane-water-pore surface,resulting a non-monotonic isotopic fractionation trend(initial increase followed by decrease).These findings provided molecular-level insights into the complex isotopic fractionation in shale gas systems.
基金financial support provided by the University of New England,Australia for conducting this research。
文摘Water-soluble organic matter(WSOM)significantly influences the transport of metals and organic contaminants in soils,yet the interaction specifics with antimony(Sb)remain largely unexplored.Antimony is of particular environmental concern due to its toxic properties and harmful effects on ecosystems and human health.Employing a three-step fractionation method with polyvinylpyrrolidone(PVP),this study aimed to isolate and analyze humic acids(HA),PVP-non adsorbed fulvic acids(FAA),and PVP-adsorbed fulvic acids(FAB)from WSOM in soil spiked with Sb and incubated for 18 months.These fractions underwent chemical analysis for carbon(C),nitrogen(N),total organic carbon(TOC),and Sb,complemented by FTIR and 1H NMR spectroscopic characterization.The study revealed that HA wasmore aliphatic,with Sb predominantly associating with the fulvic acid(FA)fraction,accounting for 97%of Sb in extracts.Specifically,the FAA subfraction held substantial portions of total carbon(TC),total nitrogen(TN),total organic carbon(TOC),and Sb.Correlations between Sb concentrations and TN,TC,and TOC were significant.Extraction methods showed NaOH and Na_(4)P_(2)O_(7) outperformed HCl and deionised water in extracting TC,TN,and TOC,with higher Sb concentrations found in Na_(4)P_(2)O_(7) and NaOH extracts.This underscores the role of Fe/Al-SOM complexes in Sb soil availability.The results revealed that FAA subfraction accounted for 76%,64%and 94%of TN,TOC and Sb,respectively.Therefore,this research highlights the FAA fraction’s central role,predominantly comprising non-humic substances like amines,in the availability of C,N,and Sb in Sb-impacted soils.The findings offer insights for environmental management and remediation strategies.
基金Youth Fund of National Natural Science Foundation of China(42302170)CNPC Scientific and Technological Innovation Fund(2022DQ02-0104)RIPED Open Project Fund(2024-KFKT-31).
文摘Taking deep coal-rock gas in the Yulin and Daning-Jixian areas of the Ordos Basin,NW China,as the research object,full-diameter coal rock samples with different cleat/fracture development degrees from the Carboniferous Benxi Formation were selected to conduct physical simulation and isotope monitoring experiments of the full-life-cycle depletion development of coal-rock gas.Based on the experimental results,a dual-medium carbon isotope fractionation(CIF)model coupling cleats/fractures and matrix pores was constructed,and an evaluation method for free gas production patterns was established to elucidate the carbon isotope fractionation mechanism and adsorbed/free gas production characteristics during deep coal-rock gas development.The results show that the deep coal-rock gas development process exhibits a three-stage carbon isotope fractionation pattern:“Stable(Ⅰ)→Decrease(Ⅱ)→Increase(Ⅲ)”.A rapid decline in boundary pressure in stageⅢleads to fluctuations in isotope value,characterized by a“rapid decrease followed by continued increase”,with free gas being produced first and long-term supply of adsorbed gas.The CIF model can effectively match measured gas pressure,cumulative gas production,and δ^(13)C_(1) value of produced gas.During the first two stages of isotope fractionation,free gas dominated cumulative production.During the mid-late stages of slow depletion production,the staged pressure control development method can effectively increase the gas recovery.The production of adsorbed gas is primarily controlled by the rock's adsorption capacity and the presence of secondary flow channels.Effectively enhancing the recovery of adsorbed gas during the late stage remains crucial for maintaining stable production and improving the ultimate recovery factor of deep coal-rock gas.
基金Supported by PetroChina Science and Technology Research and Technology Development Project(2021DJ0502)Open Research Project of Key Laboratory of Shale Gas Resources Exploration,Ministry of Natural Resources(Chongqing Institute of Geology and Mineral Resources)(KLSGE-2023).
文摘Based on geochemical data from natural gas samples across spring water systems and sedimentary basins,including Songliao,Bohai Bay,Sanshui,Sichuan,Ordos,Tarim and Ying-Qiong,this paper systematically compares the geochemical compositions of abiogenic versus biogenic gases.Emphasis is placed on the diagnostic signatures of abiogenic gases in terms of gas composition,and carbon,hydrogen and helium isotopes.The main findings are as follows.(1)In hydrothermal spring systems,abiogenic alkane gases are extremely scarce.Methane concentrations are typically less than 1%,with almost no detectable C^(2+)hydrocarbons.The gas is dominantly composed of CO_(2),while N_(2)is the major component in a few samples.(2)Abiogenic alkane gases display distinct isotopic signatures,including enriched methane carbon isotopic compositions(δ^(13)C_(1)>-25‰generally),complete carbon isotopic reversal(δ^(13)C_(1)>δ^(13)C_(2)>δ^(13)C_(3)>δ^(13)C_(4)),and enriched helium isotope(R/Ra>0.5,CH_(4)/^(3)He≤10^(6)generally).(3)The hydrogen isotopic composition of abiogenic alkane gases may be characterized by a positive sequence(δD_(1)<δD_(2)<δD_(3)),or a complete reversal(δD_(1)>δD_(2)>δD_(3)),or a V-shaped distribution(δD_(1)>δD_(2),δD_(2)<δD_(3)).The hydrogen isotopic compositions of methane generally show limited variation(about 9‰),possibly due to hydrogen isotopic exchange with connate water.(4)In terms of identifying gas origin,CH_(4)/^(3)He-R/Ra andδ^(13)CCO_(2)-R/Ra charts are more effective than CO_(2)/^(3)He-R/Ra chart.These new geological insights provide theoretical clues and diagnostic charts for the genetic identification of natural gas and further research on abiogenic gases.
文摘Lassa Fever(LF)is a viral hemorrhagic illness transmitted via rodents and is endemic in West Africa,causing thousands of deaths annually.This study develops a dynamic model of Lassa virus transmission,capturing the progression of the disease through susceptible,exposed,infected,and recovered populations.The focus is on simulating this model using the fractional Caputo derivative,allowing both qualitative and quantitative analyses of boundedness,positivity,and solution uniqueness.Fixed-point theory and Lipschitz conditions are employed to confirm the existence and uniqueness of solutions,while Lyapunov functions establish the global stability of both disease-free and endemic equilibria.The study further examines the role of the Caputo operator by solving the generalized power-law kernel via a two-step Lagrange polynomial method.This approach offers practical advantages in handling additional data points in integral forms,though Newton polynomial-based schemes are generally more accurate and can outperform Lagrange-based Adams-Bashforth methods.Graphical simulations validate the proposed numerical approach for different fractional orders(ν)and illustrate the influence of model parameters on disease dynamics.Results indicate that increasing the fractional order accelerates the decline of Lassa fever in both human and rodent populations.Moreover,fractional-order modeling provides more nuanced insights than traditional integer-order models,suggesting potential improvements for medical intervention strategies.The study demonstrates that carefully chosen fractional orders can optimize convergence and enhance the predictive capacity of Lassa fever models,offering a promising direction for future research in epidemiological modeling.
文摘Background There is still limited data on predictive value of coronary computed tomography angiography(CCTA)–derived fractional flow reserve(CT-FFR) for long term outcomes. We examined the long-term prognostic value of CT-FFR combined with CCTA–defined atherosclerotic extent in diabetic patients with coronary artery disease(CAD).Methods A retrospective pooled analysis of individual patient data was performed. Deep-learning-based vessel-specific CTFFR was calculated. All patients enrolled were followed-up for at least 5 years. Predictive abilities for major adverse cardiac events(MACE) were compared among three models(model 1), constructed using clinical variables;model 2, model 1+CCTA–derived atherosclerotic extent(Leiden risk score);and model 3, model 2+CT-FFR.Results A total of 480 diabetic patients [median age, 61(55–66) years;52.9% men] were included. During a median follow-up time of 2197(2126–2355) days, 55 patients(11.5%) experienced MACE. In multivariate-adjusted Cox models, Leiden risk score(HR: 1.06;95% CI: 1.01–1.11;P = 0.013) and CT-FFR ≤ 0.80(HR: 6.54;95% CI: 3.18–13.45;P < 0.001) were the independent predictors. The discriminant ability was higher in model 2 than in model 1(C-index, 0.75 vs. 0.63;P < 0.001) and was further promoted by adding CT-FFR to model 3(C-index, 0.81 vs. 0.75;P = 0.002). Net reclassification improvement(NRI) was 0.19(P = 0.009) for model 2 beyond model 1. Of note, adding CT-FFR to model 3 also exhibited significantly improved reclassification compared with model 2(NRI = 0.14;P = 0.011).Conclusion In diabetic patients with CAD, CT-FFR provides robust and incremental prognostic information for predicting longterm outcomes. The combined model exhibits improved prediction abilities, which is beneficial for risk stratification.
基金financially supported by the National Natural Science Foundation of China (42477044,32171648 and U23A2017)the Hubei Provincial Science and Technology Program,China (2025AFD451 and 2022CFB030)。
文摘Insight into the carbon turnover in soil aggregates and density fractions is essential for reducing the uncertainty in estimating carbon pools on the Tibetan Plateau,and how they vary with land use type is unclear.In this study,the effect of land use type on carbon storage and fractionation was quantified based on organic carbon and its ^(13)C abundance at the microscale of soil aggregates and density fractions in Tibetan alpine ecosystems.The sequence of soil aggregate destruction in the land use types of plantation(13.1%)<shrubland(32.7%)<grassland(47.9%)<farmland(61.8%)shows that plantations strengthen the soil structure.Plantation land had a greater contribution of light fraction organic carbon(28.3%)but a lower contribution of mineral-associated organic carbon(40.6%)to the carbon stock compared to farmland(13.5 and 70.3%).Interestingly,plantation land enhanced the aggregational differentiation of organic carbon and ^(13)C in each density fraction,whereas no such phenomenon existed in the soil organic carbon.Carbon isotope analyses revealed that carbon transfer in the plantation land occurred from the light fraction in macroaggregates(–24.9‰)to the mineral-associated fraction in microaggregates(–19.9‰).When compared to the other three land use types,the low transferability of carbon in aggregates and density fractions in plantation land provides a stable carbon pool for the Tibetan Plateau.This study shows that plantations can mitigate global climate change by slowing carbon transfer and increasing carbon storage at the microscale of aggregates and density fractions in alpine regions.
文摘Grifola frondosa(Maitake)is traditionally valued for its health benefits,with polysaccharides being key bioactive components.This paper investigates a specific subfraction,Fraction D(GFP-D),evaluating its clinical effects and mechanisms in immune enhancement,adjunctive anti-tumor activity,and regulation of glucose/lipid metabolism.Three clinical trials were conducted.In an immune study,120 healthy volunteers(CD4+T cell count 500–1000 cells/μL)received 150 mg/day GFP-D for 8 weeks,resulting in significant increases in CD4+T cells(from 632±95 to 812±108 cells/μL,28.5%increase,within the physiological activation range),CD4+/CD8+ratio,NK cell activity,IL-2,and IFN-γ(all P<0.001 vs.placebo).An anti-tumor study with 80 advanced cancer patients(stratified by age,tumor stage,and histotype)showed that adding 1000 mg/day GFP-D to chemotherapy improved objective response rate(52.5%vs.30.0%,P=0.036,95%CI:1.02–3.87),one-year progression-free survival(55.8%vs.33.3%,P=0.022),and preserved immune parameters versus chemotherapy alone.A metabolic study in 90 type 2 diabetes patients found that 400 mg/day GFP-D for 12 weeks significantly lowered fasting glucose,HbA1c,total cholesterol,triglycerides,and LDL-C,while raising HDL-C(from 1.0±0.2 to 1.2±0.2 mmol/L,20%increase,supported by increased AMPK phosphorylation).Mechanistically,immune enhancement involves macrophage/dendritic cell activation via Dectin-1/TLR4 receptors(confirmed by increased receptor expression and downstream signaling molecules),promoting cytokine-driven T/NK cell responses.Anti-tumor effects stem from immunomodulation,direct induction of cancer cell apoptosis(via mitochondrial/caspase pathways,verified by increased Bax/Bcl-2 ratio and caspase-3 activation),and angiogenesis inhibition by downregulating VEGF.Metabolic benefits are linked to AMPK pathway activation in liver/muscle(confirmed by increased p-AMPK/AMPK ratio),enhancing glucose uptake and inhibiting gluconeogenesis/lipogenesis,alongside modulation of gut microbiota(increased Bifidobacterium and Lactobacillus abundance).All trials reported no severe adverse events related to GFP-D;liver/kidney function parameters(ALT,AST,creatinine,urea nitrogen)remained within normal ranges throughout the intervention.Collectively,GFP-D emerges as a multi-functional bioactive agent with substantial therapeutic potential.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11961041,12261055)the Key Project of Natural Science Foundation of Gansu Province(Grant No.24JRRA222)the Foundation for Innovative Fundamental Research Group Project of Gansu Province(Grant No.25JRRA805).
文摘In this paper,we first give a sufficient condition for a graph being fractional ID-[a,b]-factor-critical covered in terms of its independence number and minimum degree,which partially answers the problem posed by Sizhong Zhou,Hongxia Liu and Yang Xu(2022).Then,an A_(α)-spectral condition is given to ensure that G is a fractional ID-[a,b]-factor-critical covered graph and an(a,b,k)-factor-critical graph,respectively.In fact,(a,b,k)-factor-critical graph is a graph which has an[a,b]-factor for k=0.Thus,these above results extend the results of Jia Wei and Shenggui Zhang(2023)and Ao Fan,Ruifang Liu and Guoyan Ao(2023)in some sense.
基金Supported by National Natural Science Foundation of China(31172245)Major Agricultural Application Technology Innovation Project in Shandong Province(LCNZ[2014]38)~~
文摘[Objective] This study aimed to promote the combination of cultivation and livestock farming, and to explore an environment-protecting farming style. [Method]The effects of anaerobically fermented complete compound sow feed, added with Lactobacillus and Bacillus subtilis, on the chemical fractionation of copper, iron, zinc and manganese in feed and pig manure and skatole content in pig manure were investigated. [Result] Compared with those in the non-fermented feed, in the fermented feed and pig manure, the acetic acid-extractable copper, iron, zinc and manganese contents increased significantly（P0.05）, the reduced copper and iron contents increased significantly（P 0.05）, the oxidized copper and iron contents reduced significantly（P0.05）, and the residual copper contents remained unchangeable（P0.05）. The pH value of fermented feed decreased significantly（P0.05）, and that of pig manure increased significantly（P0.05）. The skatole content in pig manure decreased significantly（P 0.01）. The Lactobacillus abundance and amylase and cellulase activity increased significantly（P 0.05）. [Conclusion] The fermentation of feed changed the chemical fractionation of copper, iron, zinc and manganese in feed and pig manure, and reduced the manure odor.
基金The Grand Projects of Innovation Engineering Chinese Academy of Sciences(No. KZCX1 SW 12 2002 2006)
文摘Typical sediments from Taihu Lake, a meso-to-hypereutrophic lake, were collected and examined on the basis of P-fractionation by sequential extraction scheme. Sedimentary inorganic phosphorus were fractioned into four forms and the rank order according to the mean concentration of P-fractions in Taihu Lake was NaOH-P>BD-P>HCl-P>NH_4Cl-P. The concentrations of BD-P were linearly correlated with the content of active Fe(R2=0.96). Also, the linear relationship between the sum of BD-P and NaOH-P and the sum of active Fe and active Al content was observed within the six sediments investigated(R2=0.96). Moreover, the bio-available phosphorus(BAP) content was estimated by the sum of NH_4Cl-P, BD-P, and NaOH-P, viz. BAP=NH_4Cl-P+NaOH-P+BD-P. In Taihu Lake, the BAP contents are ranging from 0.10 mg/g dw to 1.25 mg/g dw, and average 0.40 mg/g dw for all sediment samples. The relative contributions of BAP to total sedimentary phosphorus(TP) and inorganic sedimentary phosphorus(IP) range from 18.67% to 50.79%(33.61% on average) and from 52.82% to 82.09%(67.81% on average), respectively.
基金supported by the National Basic Research Program of China(973 Program) (2009CB421006)the State Key Laboratory of Geological Processes and Mineral Resources (GPMR200843)
文摘REE fractionation during the weathering of dolomite has been recognized for decades.A regolith profile on dolomite in southwest Yunnan of China was selected to investigate the behaviors of REE during weathering.The weathering of dolomite is divided into two stages：the pedogenesis stage and soil evolution stage,corresponding to the saprolites and soils respectively in the regolith profile. SiO_2,TiO_2,P_2O_5,Zr,Hf,Nb and Ta were immobile components during the weathering by and large, while Al_2O_3,K_2O and Fe_2O_3 were lost during the soil evolution stage in the physical form（clay minerals probably）.REE were fractionated during the whole weathering of dolomite.The field weathering profile and the lab acid-leaching experiments on dolomite indicate that MREE were enriched clearly relative to other REE during the pedogenesis stage in a ＂capillary ascending-adsorption＂ mechanism, but they did not fractionate clearly in the soil evolution stage.REE were lost and accumulated in the weathering front of dolomite during the soil evolution stage in a ＂physical-chemical leaching＂ mechanism.
基金Project supported by the National Natural Science Foundation of China (40571146)
文摘Studies were carried out on several aspects of rare earth elements （REEs）, such as the theory and practice of their applications in agriculture, their geochemical behaviors in natural and agricultural ecosystems, the mechanisms for the increase of crop yield using REE fertilizer, and their toxicology. However, limited knowledge was available for the transfer processes and the features and mechanisms of distribution and fractionations of REEs inside plants. The characteristics of REE fractionations in plants can be used to ＂trace＂ the pathway of REE transportation from soils （solution） to plants. A better understanding of the mechanisms of REE fractionations was helpful to investigate the controlling factors, including both the internal and the external ones. The characteristics and mechanisms of REE fractionations in plants and their significance were reviewed. Furthermore, the prospect for these fields was discussed, in hope of providing a new way in studying the bioavailability of REEs and heavy metals.
基金supported by the National Natural Science Foundation of China (No.30870452)the National Chaohu Lake Special Project of China (No.2008ZX07103-005)
文摘^ 15N isotope tracer techniques and ecological modeling were adopted to investigate the fractionation of nitrogen, its uptake and transformation in algae and snail （Bellamya aeruginosa Reeve）. Different algal species were found to differ in their uptake of nitrogen isotopes. Microcystis aeruginisa Ktitz. demonstrated the greatest ^15N accumulation capacity, with the natural variation in isotopic ratio （δ^15N） and the isotope fractionation factor （ε,‰） being the highest among the species investigated. The transformation and utilization of ^15N by snails differed depending on the specific algae consumed （highest for Chlorella pyrenoidosa Chick., lowest for M. aeruginisa）. When snails was seeded in the experimental pond, the algae population structure changed significantly, and total algal biomass as well as the concentration of all nitrogen species decreased, causing an increase in water transparency. A model, incorporating several chemical and biological parameters, was developed to predict algal biomass in an aquatic system when snails was present. The data collected during this investigation indicated that the gastropods such as snails could significantly impact biological community and water quality of small water bodies, suggesting a role for biological control of noxious algal blooms associated with eutrophication.
基金supported by the International Research Group Project (No. IRG-14-02) from the Deanship of Scientific Research at King Saud University, Saudi Arabia
文摘In most arid and semiarid soils, naturally occurring phosphorus(P) is a major yield-limiting plant nutrient. In this study, to investigate the effects of organic(OP) and inorganic P(IP) sources on P fractionation, a calcareous sandy loam alkaline soil was fertilized with OP and IP fertilizers at low(80 mg P kg^(-1) soil) and high(160 mg P kg^(-1) soil) application rates. Three combinations of OP and IP(i.e., 75% OP + 25% IP, 50% OP + 50% IP, and 25% OP + 75% IP) were applied at low and high application rates,respectively, followed by soil aging for 21 d. Soil samples were collected after 1, 2, 3, 7, and 21 d and subjected to sequential extraction to analyze soluble and exchangeable, Fe-and Al-bound, Ca-bound, and residual P fractions. The soluble and exchangeable P fraction significantly increased up to 24.3%, whereas the Ca-bound fraction decreased up to 40.7% in the soils receiving 75% OP + 25% IP and 50% OP + 50% IP, respectively, compared with the control(receiving no P fertilizer). However, the transformation of P fractions was influenced by aging time. Addition of P sources caused instant changes in different P fractions, which then tended to decline with aging time. Change in soil p H was the limiting factor in controlling P availability. At high application rate, the OP source significantly increased soil P availability compared with the IP source with soil aging. Depending on P fractionation, a proper combination of OP and IP fertilizers, as long-term slow and instant P-releasing sources for plant uptake, respectively, may be a sustainable strategy to meet crop P requirements in the arid and semiarid soils.
基金supported by the National Natural Science Foundation of China (No. 40903052,41273151)the National Basic Research Program (973) of China (No.2008CB418006)the opening foundation of Guizhou University (No. 2009GDGP0105)
文摘The distribution characteristics of phosphorus （P） forms in the sediment profile of Lake Erhai, in southwestern China has been investigated by sequential extraction and 31p nuclear magnetic resonance spectroscopy （NMR） of NaOH extracts to understand P dynamics and its potential contribution to lake eutrophication. Contents of P fractions varied in the order of NH4C1 extracted P （NH4C1- P） 〈 bicarbonate-dithionite extracted P （BD-P） 〈 HC1-P, Residual-P 〈 NaOH extracted P （NaOH-P）. The highly available NH4C1-P represented less than 1% of total P （TP）. BD-P and NaOH extracted reactive P （NaOH-rP） averaged 39%, while the ratio of Fe/P was higher than 15, indicating low P release from the sediments under permanent oxic condition. The less bio-available HC1-P, NaOH extracted nonreactive P （NaOH-nrP） and residual-P contributed 61% of TP. Regression analysis revealed that BD-P, NaOH-rP and HC1-P were positively correlated with the contents of Fe and Mn, A1 and Fe, and Ca, respectively. The investigation of P compound groups in NaOH extracts by 31p NMR showed that ortho-P and monoester-P were the largest two constituents of the P pool, followed by diester-P, phosphonate and pyro-P. A comparison of vertical variations of P groups in the sediment profile suggested that these compounds were involved in the P recycling to different extents in Lake Erhai. In particular, the lake exhibits high potential for labile P release from the surface sediments, which should be taken into consideration even after the outsourced P runoff ceased.
