A developed method was used for the enhancement of arachidonic acid production by M. isabellina. An orthogonal, rotatable and central composite design was applied to determine the optimum conditions for protoplast reg...A developed method was used for the enhancement of arachidonic acid production by M. isabellina. An orthogonal, rotatable and central composite design was applied to determine the optimum conditions for protoplast regeneration mutagenesis. The results showed that a commixture enzyme （cellulase and glusulase） at the concentration of 4%, enzymolysis temperature at 30℃ and enzymolysis time on 7.5 h were the optimal conditions, in which the lethality of M. isabellina spores was 78.4%. After mutagenesis and re-screenings, M. isabellina mutant Y-69 was obtained. GC analysis showed that the yield of arachidonic acid by Y-69 （2.92 g. L-1） was 3.56 times higher than that of the wild-type strain （0.82 g.L-1）. Pass generation tests showed that the properties of Y-69 by mutation were readily inherited.展开更多
Arachidonic acid （AA or ARA）, an essential to-6 polyunsaturated fatty acid （PUFA）, can be produced by Mortierella isabellina. Mutagenesis on Mortierella isabellina As3.3410 was induced to raise ARA production. The...Arachidonic acid （AA or ARA）, an essential to-6 polyunsaturated fatty acid （PUFA）, can be produced by Mortierella isabellina. Mutagenesis on Mortierella isabellina As3.3410 was induced to raise ARA production. The mutant strain of YZ-124 had the highest ARA of 4.72 g. L-1, which was 5.5 times higher than that of the original strain 3.3410. mRNA expression level of △ 6- desaturase was determined in five different kinds of ARA-producing Mortierella isabellina after cultured for 7 days, and in the mutant strain YZ-124 over a 3-8 day time-course. In addition, the desaturase activity and ARA content were measured at the selected time points. The lowest expression of △6-desaturase was observed in the original strain and the highest expression in the mutant strain YZ-124, which increased with increasing time in culture. Furthermore, a positive correlation was observed between the expression levels of △6-desaturase and ARA content. Based on this, △6-desaturase played a significant role in ARA synthesis pathway in Mortierella isabellina.展开更多
Objective Traditional Chinese medicine(TCM)constitutes a valuable cultural heritage and an important source of antitumor compounds.Poria(Poria cocos(Schw.)Wolf),the dried sclerotium of a polyporaceae fungus,was first ...Objective Traditional Chinese medicine(TCM)constitutes a valuable cultural heritage and an important source of antitumor compounds.Poria(Poria cocos(Schw.)Wolf),the dried sclerotium of a polyporaceae fungus,was first documented in Shennong’s Classic of Materia Medica and has been used therapeutically and dietarily in China for millennia.Traditionally recognized for its diuretic,spleen-tonifying,and sedative properties,modern pharmacological studies confirm that Poria exhibits antioxidant,anti-inflammatory,antibacterial,and antitumor activities.Pachymic acid(PA;a triterpenoid with the chemical structure 3β-acetyloxy-16α-hydroxy-lanosta-8,24(31)-dien-21-oic acid),isolated from Poria,is a principal bioactive constituent.Emerging evidence indicates PA exerts antitumor effects through multiple mechanisms,though these remain incompletely characterized.Neuroblastoma(NB),a highly malignant pediatric extracranial solid tumor accounting for 15%of childhood cancer deaths,urgently requires safer therapeutics due to the limitations of current treatments.Although PA shows multi-mechanistic antitumor potential,its efficacy against NB remains uncharacterized.This study systematically investigated the potential molecular targets and mechanisms underlying the anti-NB effects of PA by integrating network pharmacology-based target prediction with experimental validation of multi-target interactions through molecular docking,dynamic simulations,and in vitro assays,aimed to establish a novel perspective on PA’s antitumor activity and explore its potential clinical implications for NB treatment by integrating computational predictions with biological assays.Methods This study employed network pharmacology to identify potential targets of PA in NB,followed by validation using molecular docking,molecular dynamics(MD)simulations,MM/PBSA free energy analysis,RT-qPCR and Western blot experiments.Network pharmacology analysis included target screening via TCMSP,GeneCards,DisGeNET,SwissTargetPrediction,SuperPred,and PharmMapper.Subsequently,potential targets were predicted by intersecting the results from these databases via Venn analysis.Following target prediction,topological analysis was performed to identify key targets using Cytoscape software.Molecular docking was conducted using AutoDock Vina,with the binding pocket defined based on crystal structures.MD simulations were performed for 100 ns using GROMACS,and RMSD,RMSF,SASA,and hydrogen bonding dynamics were analyzed.MM/PBSA calculations were carried out to estimate the binding free energy of each protein-ligand complex.In vitro validation included RT-qPCR and Western blot,with GAPDH used as an internal control.Results The CCK-8 assay demonstrated a concentration-dependent inhibitory effect of PA on NB cell viability.GO analysis suggested that the anti-NB activity of PA might involve cellular response to chemical stress,vesicle lumen,and protein tyrosine kinase activity.KEGG pathway enrichment analysis suggested that the anti-NB activity of PA might involve the PI3K/AKT,MAPK,and Ras signaling pathways.Molecular docking and MD simulations revealed stable binding interactions between PA and the core target proteins AKT1,EGFR,SRC,and HSP90AA1.RT-qPCR and Western blot analyses further confirmed that PA treatment significantly decreased the mRNA and protein expression of AKT1,EGFR,and SRC while increasing the HSP90AA1 mRNA and protein levels.Conclusion It was suggested that PA may exert its anti-NB effects by inhibiting AKT1,EGFR,and SRC expression,potentially modulating the PI3K/AKT signaling pathway.These findings provide crucial evidence supporting PA’s development as a therapeutic candidate for NB.展开更多
Herein,a one-pot chemical reduction method was reported to prepare folic acid(FA)-stabilized silver nanoclusters(FA@Ag NCs),in which FA,hydrazine hydrate,and silver nitrate were used as capping agent,reducing agent,an...Herein,a one-pot chemical reduction method was reported to prepare folic acid(FA)-stabilized silver nanoclusters(FA@Ag NCs),in which FA,hydrazine hydrate,and silver nitrate were used as capping agent,reducing agent,and precursor,respectively.Several technologies were employed to investigate the structures and optical properties of FA@Ag NCs,including transmission electron microscopy(TEM),X-ray photoelectron spectrometer(XPS),Fourier transform infrared spectrometer(FTIR),X-ray diffractometer(XRD),fluorescence spectrometer,and ultraviolet visible absorption spectrometer.FA@Ag NCs were suggested to be highly dispersed and spherical with a size of around 2.8 nm.Moreover,the maximum excitation and emission wavelengths of FA@Ag NCs were 370 and 447 nm,respectively.Under the optimal detection conditions,FA@Ag NCs could be used to effectively detect malachite green with the linear detection range of 0.5-200μmol·L^(-1).The detection limit was 0.084μmol·L^(-1).The fluorescence-quenching mechanism was ascribed to the static quenching.The detection system based on FA@AgNCs was successfully used for the detection of malachite green in actual samples with good accuracy and reproducibility.展开更多
In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were inve...In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were investigated.The results showed that the three materials had satisfactory compatibility in the composite film.Addition of EC and zein effectively improved the mechanical properties,thermodynamic properties,surface hydrophilicity,oxygen permeability,and degradation properties of PLA films.When the ratio of PLA to EC was 3:7,the tensile strength and elongation at break reached maximum values of 16.6 MPa and 30.5%,respectively.Moreover,under different conditions,the composite film exhibited better degradability than the PLA film.The composite film with a 3:7 ratio of PLA to EC had the best performance,with a degradation rate of 21.75%after 84 days.Chilled fresh meat wrapped with the composite film showed significantly improved antioxidant,antibacterial,and water-holding properties.展开更多
This study aimed to investigate the effects of dietary guanidinoacetic acid on growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.Total 48042-day-old female ducks wer...This study aimed to investigate the effects of dietary guanidinoacetic acid on growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.Total 48042-day-old female ducks were randomly divided into four groups with six replicates and 20 ducks per replicate and fed the basal diet to the control group.The experimental groups were fed the basal diet with 400,600 and 800 mg·kg^(-1) guanidinoacetic acid,respectively.The trial lasted 48 days.Compared with the control group,(1)the body weight at 90 days and average daily gain were increased(P<0.05),the feed conservation ratio was decreased(P<0.05);(2)the dressing percentage and breast muscle percentage were increased(P<0.05);(3)the total amino acid content,polyunsaturated fatty acids to monounsaturated fatty acids ratio were increased(P<0.05)in breast and thigh muscles;(4)activities of superoxide dismutase,catalase and glutathione peroxidase enzyme were increased(P<0.05)in thigh muscles;(5)the relative expressions of superoxide dismutase 1,glutathione peroxidase 1,and catalase were significantly increased(P<0.05)in the liver.In this study,the optimum dosage of 600 mg·kg^(-1) guanidinoacetic acid improved the growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.展开更多
Objective:The neurotoxicity of carbon monoxide(CO)to the central nervous system is a key pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning(DEACMP).Our previous study found that retinoic acid...Objective:The neurotoxicity of carbon monoxide(CO)to the central nervous system is a key pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning(DEACMP).Our previous study found that retinoic acid(RA)can suppress the neurotoxic effects of CO.This study further explores,in vivo and in vitro,the molecular mechanisms by which RA alleviates CO-induced central nervous system damage.Methods:A cytotoxic model was established using the mouse hippocampal neuronal cell line HT22 and primary oligodendrocytes exposed to CO,and a DEACMP animal model was established in adult Kunming mice.Cell viability and apoptosis of hippocampal neurons and oligodendrocytes were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay and Annexin V/propidium iodide(PI)double staining.The transcriptional and protein expression of each gene was detected using real time fluorescence quantitative PCR(RT-qPCR)and Western blotting.Long noncoding RNA(lncRNA)SNHG15 and LINGO-1 were knocked down or overexpressed to observe changes in neurons and oligodendrocytes.In DEACMP mice,SNHG15 or LINGO-1 were knocked down to assess changes in central nervous tissue and downstream protein expression.Results:RA at 10 and 20μmol/L significantly reversed CO-induced apoptosis of hippocampal neurons and oligodendrocytes,downregulation of SNHG15 and LINGO-1,and upregulation of brain-derived neurotrophic factor(BDNF)and tyrosine kinase receptor B(TrkB)(all P<0.05).Overexpression of SNHG15 or LINGO-1 weakened the protective effect of RA against CO-induced cytotoxicity(all P<0.05).Knockdown of SNHG15 or LINGO-1 alleviated CO-induced apoptosis of hippocampal neurons and oligodendrocytes and upregulated BDNF and TrkB expression levels(all P<0.05).Experiments in DEACMP model mice showed that knockdown of SNHG15 or LINGO-1 mitigated central nervous system injury in DEACMP(all P<0.05).Conclusion:RA alleviates CO-induced apoptosis of hippocampal neurons and oligodendrocytes,thereby reducing central nervous system injury and exerting neuroprotective effects.LncRNA SNHG15 and LINGO-1 are key molecules mediating RA induced inhibition of neuronal apoptosis and are associated with the BDNF/TrkB pathway.These findings provide a theoretical framework for optimizing the clinical treatment of DEACMP and lay an experimental foundation for elucidating its molecular mechanisms.展开更多
The influence of grain size or grain refinement on the corrosion of Zr alloy is clarified by employing a series of electrochemical analyses and characterization techniques.The corrosion resistance,as a function of exp...The influence of grain size or grain refinement on the corrosion of Zr alloy is clarified by employing a series of electrochemical analyses and characterization techniques.The corrosion resistance,as a function of exposure time,F−concentration,and solution temperatures,of Zr alloys with different grain sizes is ascertained.The results confirm that refining the grain size can effectively enhance the short-time corrosion properties of Zr alloy in HNO_(3) with F−.The fine grained Zr alloy(~10μm in diameter)consistently exhibits a lower corrosion current density,ranging from 18%to 46%lower than that of the coarse-grained Zr alloy(~44μm).The enhanced corrosion resistance is attributed to the high density grain boundaries,which promote oxide stability,and accelerate the creation of the protective layer.The high corrosion rate and pseudo-passivation behavior of Zr alloys in fluorinated nitric acid originate from the accelerated“dissolution-passivation”of the oxide film.However,the grain refinement does not provide enduring anti-corrosion for Zr alloys.To meet the operation of spent fuel reprocessing,additional systematic efforts are required to evaluate the long term effect of grain refinement.展开更多
Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the...Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the impact of nitric acid oxidation on the surface of carbonized melamine foam and its microwave absorption properties.The treated foam exhibits optimal reflection loss of−21.51 dB at 13.20 GHz,with an effective absorption bandwidth of 7.04 GHz.The enhanced absorption properties are primarily attributed to the strengthened dielectric loss,improved impedance matching,and increased polarization losses resulting from the oxidized surfaces.This research demonstrates a promising new approach for research into surface treatments to improve the performances of microwave absorbers.展开更多
Background Verticillium dahliae,a soil-borne fungi,can cause Verticillium wilt,and seriously diminish the yield and quality of cotton.However,the pathogenic mechanism of V.dahliae is complex and not clearly understood...Background Verticillium dahliae,a soil-borne fungi,can cause Verticillium wilt,and seriously diminish the yield and quality of cotton.However,the pathogenic mechanism of V.dahliae is complex and not clearly understood at the moment.This study aimed to identify the high-affinity nicotinic acid transporter genes in V.dahliae.The gene expression profiles in V.dahliae following sensing of root exudates from susceptible and resistant cotton varieties were analyzed.The function of VdNAT1 in the pathogenic process of V.dahliae was studied using the tobacco rattle virus(TRV)-based host-induced gene silencing(HIGS)technique.Results Eight high-affinity nicotinic acid transporter genes were identified from V.dahliae through the bioinformatics method.Each protein contains a conserved major facilitator superfamily(MFS)domain,which belongs to the MFS superfamily.Evolutionary relationship analysis revealed that all 8 genes belong to the anion:cation symporter(ACS)subfamily.All proteins have transmembrane domains,ranging from 7 to 12.The expression levels of most VdNAT genes were significantly increased after induction by root exudates from susceptible cotton varieties.Silencing VdNAT1 gene by HIGS significantly inhibited the accumulation of fungal biomass in cotton plants,and alleviated the disease symptoms of cotton.Conclusions Eight VdNAT genes were identified from V.dahliae,and most VdNAT genes was up-regulated after induced by root exudates from susceptible cotton variety.In addition,VdNAT1 is required for the pathogenicity of V.dahliae.Overall,these findings will facilitate the pathogenic molecular mechanism of V.dahliae and provide candidate genes.展开更多
Objective:Oleic acid,a subtype of monounsaturated fatty acid(MUFA),is present in abundance in certain edible oils,particularly olive oils.Epidemiological evidence concerning dietary oleic acid intake and the long-term...Objective:Oleic acid,a subtype of monounsaturated fatty acid(MUFA),is present in abundance in certain edible oils,particularly olive oils.Epidemiological evidence concerning dietary oleic acid intake and the long-term risk of mortality is lacking.This study aimed to evaluate the associations of the dietary intake of oleic acid and other specific subtypes of MUFAs,olive oil,and other vegetable oils with cardiovascular disease(CVD)and all-cause mortality.Methods:This prospective cohort study included adults aged 40 years or older who participated in the included U.S.adults National Health and Nutrition Examination Survey(NHANES).Dietary MUFA intake was assessed via 24-h dietary recall interviews in NHANES 1999–2018,and the consumption of olive oil and other vegetable oils was assessed via a food frequency questionnaire in NHANES 2003–2006.Deaths and underlying causes of death were ascertained by linkage to the National Death Index through December 31,2019.Weighted Cox proportional hazards regression models were used to estimate the hazard ratio(HR)and 95%CIs.Results:Dietary intake of total MUFAs and oleic acid was associated with a lower risk of CVD mortality,with HRs(95%CI)of 0.62(0.39–0.99)and 0.61(0.39–0.97),respectively.Total MUFA and oleic acid intake were inversely associated with all-cause mortality;the multivariable-adjusted HRs were 0.77(95%CI:0.60–0.99)and 0.78(95%CI:0.62–0.99),respectively.There was no significant association between palmitoleic acid intake and all-cause mortality.The habitual consumption of olive oil,but not the consumption of other vegetable oils,was inversely associated with the risk of cardiovascular mortality.In the joint association analysis,the HRs(95%CI)of cardiovascular mortality were 0.36(0.19–0.69)for people who exclusively consumed olive oil,0.59(0.27–1.32)for people who consumed both olive oil and other vegetable oils,and 0.73(0.46–1.14)for people who exclusively consumed other vegetable oils compared with people who never consumed vegetable oils.Conclusions:In a U.S.nationally representative prospective cohort,higher dietary oleic acid intake and olive oil consumption were associated with a lower risk of cardiovascular mortality.展开更多
Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been construc...Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been constructed hydrothermally using H_(2)cpna(5-(4-carboxyphenoxy)nicotinic acid),dpea(1,2-di(4-pyridyl)ethane),dpey(1,2-di(4-pyridyl)ethylene),and zinc,cobalt,and nickel chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the triclinic system,space group P1.Compounds 1-3 show 2D layer structures.The catalytic activities in the Knoevenagel condensation reaction of these compounds were investigated.Compounds 1 and 2 exhibit effective catalytic activities in the Knoevenagel condensa-tion reaction at room temperature.For this reaction,various parameters were optimized,followed by the investiga-tion of the substrate scope.CCDC:2335676,1;2335677,2;2335678,3.展开更多
Herein,a layered chiral coordination polymer,[Cd2(D‑cam)_(2)(2,2′‑bipy)_(2)]_(n)(Cd‑CP),was synthesized using a solvothermal method with camphoric acid(D‑H_(2)cam),2,2′‑bipyridine(2,2′‑bipy)and Cd^(2+),and Tb^(3+)@...Herein,a layered chiral coordination polymer,[Cd2(D‑cam)_(2)(2,2′‑bipy)_(2)]_(n)(Cd‑CP),was synthesized using a solvothermal method with camphoric acid(D‑H_(2)cam),2,2′‑bipyridine(2,2′‑bipy)and Cd^(2+),and Tb^(3+)@Cd‑CP was in‑situ synthesized introducing Tb^(3+)ions.The fluorescence experiments revealed that compared to Cd‑CP,Tb^(3+)@Cd‑CP exhibited ultra‑high fluorescence performance.The luminescence sensing performance demonstrated that Tb^(3+)@Cd‑CP could distinguish R/S‑propylene glycol(R/S‑PG)by fluorescence responses,with fluorescence quenching constant of 5.3×10^(3)and 2.0×10^(3)L·mol^(-1)respectively and the enantioselectivity factor(α)of 2.65.Moreover,Tb^(3+)@Cd‑CP demonstrated limits of detection of 9.3 and 19.0μmol·L^(-1)for R‑PG and S‑PG,respectively,and showed good reproducibility.展开更多
Biomass-derived platform molecules,such as furfural,are abundant and renewable feedstock for valuable chemical production.It is critical to synthesize highly efficient photocatalysts for selective oxidation under visi...Biomass-derived platform molecules,such as furfural,are abundant and renewable feedstock for valuable chemical production.It is critical to synthesize highly efficient photocatalysts for selective oxidation under visible light.The Er@K-C_(3)N_(4)/UiO-66-NH_(2) catalyst was synthesized using a straight-forward hydrothermal technique,and exhibited exceptional efficiency in the photocatalytic oxidation of furfural to furoic acid.The catalyst was thoroughly characterized,confirming the effective adjustment of the band gap energy of Er@K-C_(3)N_(4)/UiO-66-NH_(2).Upon the optimized reaction conditions,the conversion rate of furfural reached 89.3%,with a corresponding yield of furoic acid at 79.8%.The primary reactive oxygen species was identified as·O_(2)^(-) from ESR spectra and scavenger tests.The incorporation of Er and K into the catalyst enhanced the photogenerated carriers transfer rate,hence increasing the separating efficiency of photogenerated electron-hole pairs.This study expands the potential applications of rare earth element doped g-C_(3)N_(4) in the photocatalytic selective oxidation of furfurans.展开更多
Based on the criteria for additional surface acidity generation in composite oxides and composite fluorides proposed by Tanabe and Kemnitz et al.A hypothesis for the origin of additional surface acidity in solid compo...Based on the criteria for additional surface acidity generation in composite oxides and composite fluorides proposed by Tanabe and Kemnitz et al.A hypothesis for the origin of additional surface acidity in solid composites with the same metal cations is proposed.The surface acidsites of We analyze three types of solid composite systems,that is,CrF_(3)/Cr_(2)O_(3),MgF_(2)/MgO,and ZnF_(2)/ZnO,is systematically analyzed,which agrees with experimental results.Accordingly,the origin of additional surface acidity in these solid composites is reasonably explained,and the types of acidic sites are also predicted.展开更多
The corrosion behavior of the acidophilic sulfur-oxidizing microorganism(ASOM)Acidithiobacillusthiooxidans(A.thiooxidans)on mortar was investigated for changes of medium and mortar,as well as for weight lossand surfac...The corrosion behavior of the acidophilic sulfur-oxidizing microorganism(ASOM)Acidithiobacillusthiooxidans(A.thiooxidans)on mortar was investigated for changes of medium and mortar,as well as for weight lossand surface morphology of mortar specimens.Weight loss analysis showed that mortar weight was reduced by(15.1±2.2)%after 56 d.Morphological surface analysis of mortar specimens showed weakly structured fibrous substances with2−100μm in size.The pH variations of the mortar surface and medium indicated that biogenic sulfuric acid had beenproduced by A.thiooxidans.The results prove that A.thiooxidans accelerated concrete corrosion and caused concretefailure.展开更多
OBJECTIVE To investigate whether aldo-keto reductases(AKRs)can act as a nitrore⁃ductase(NR)and bioactivate aristolochic acidⅠ(AA-Ⅰ)to produce AA-Ⅰ-DNA adducts.METHODS①Human-induced hepatocytes(hiHeps)and human bla...OBJECTIVE To investigate whether aldo-keto reductases(AKRs)can act as a nitrore⁃ductase(NR)and bioactivate aristolochic acidⅠ(AA-Ⅰ)to produce AA-Ⅰ-DNA adducts.METHODS①Human-induced hepatocytes(hiHeps)and human bladder RT4 cells were used as tool cells and treated with AA-Ⅰ0,0.5,1.0 and 2μmol·L^(-1)for 24 h.Cell viability was detected using the CCK-8 method,and the half maximal inhibition concentration(IC_(50))was calculated using the CCK-8 method and the level of DNA adduct production was calculated.②hiHeps and RT4 cells were treated with AKR inhibitor luteotin(0,5,10 and 25μmol·L^(-1))+AA-Ⅰ0.2 and 1.0μmol·L^(-1)for 24 h,respectively,and the levels of DNA adducts were detected by a liquid chromatography-tandem mass spectrometer(LC-MS/MS).③hiHeps cells were incubated with 80 nmol·L^(-1)small interfering RNAs(si-AKRs)for 48 h and treated with AA-Ⅰ1.0μmol·L^(-1)for 24 h.Real-time qualitative PCR(RT-qPCR)method was used to detect the mRNA expression of AKRs gene and LC-MS/MS technology was used to investigate the effect of specific AKR gene knockdown on DNA adduct levels.④500 nmol·L^(-1)human AKR recombinant proteins AKR1A1 and AA-Ⅰwere incubated in vitro under anaerobic conditions and the formation of AA-Ⅰ-DNA adducts was detected.RESULTS①The IC_(50)of AA-Ⅰto hiHeps and RT4 cells was 1.9 and 0.42μmol·L^(-1),respec⁃tively.The level of DNA adduct production of the two cell lines was significantly different(P<0.01).②Luteolin≥5μmol·L^(-1)significantly inhibited the production of AA-Ⅰ-DNA adducts in both cells(P<0.05),and there was a concentration-dependent effect in hiHeps cells(P<0.01,R=0.84).③In the AKR family,the knockdown of AKR1A1 gene up to 80%inhibited the generation of AA-Ⅰ-DNA adducts by 30%-40%.④The AA-Ⅰ-DNA adducts were detected in the incubation of recombinant protein AKR1A1 and AA-Ⅰunder anaerobic conditions in vitro,approximately 1 adduct per 107 nucleotides.CONCLU⁃SION AKR1A1 is involved in AA-Ⅰbioactivation,providing a reference for elucidation of the carcino⁃genic mechanism of AA-Ⅰ.展开更多
Spent fuel reprocessing plays a pivotal role in achieving efficient recycling of nuclear fuel.Among thedifferent forms of failure encountered in spent fuel reprocessing,tribocorrosion stands out as a critical concern....Spent fuel reprocessing plays a pivotal role in achieving efficient recycling of nuclear fuel.Among thedifferent forms of failure encountered in spent fuel reprocessing,tribocorrosion stands out as a critical concern.Herein,the tribocorrosion behavior,as well as the corrosion behavior,of 304L stainless steel(SS)in high-temperatureconcentrated nitric acid was investigated.The results indicated that 304L SS formed a thin(1.54 nm)and stable passivefilm on the surface,imparting high resistance to nitric acid corrosion.Meanwhile,it was found that the synergistic effectbetween corrosion and wear accounted for a high total tribocorrosion weight loss of over 85%,implying the dominantrole of the synergistic effect in the tribocorrosion process.Furthermore,the wear of 304L SS in deionized water revealedboth abrasive and adhesive wear characterizations,whereas the tribocorrosion in nitric acid only exhibited abrasive wearfeature.Eventually,the tribocorrosion and corrosion models of 304L SS in hot concentrated nitric acid were proposedbased on the comprehensive experimental findings.展开更多
Cold stress adversely affects rice growth,particularly at the early vegetative growth stage.In higher plants,nitrogen metabolism plays a central role in amino acid metabolism,plant defense mechanisms and productivity....Cold stress adversely affects rice growth,particularly at the early vegetative growth stage.In higher plants,nitrogen metabolism plays a central role in amino acid metabolism,plant defense mechanisms and productivity.This report investigated the effects of cold stress and supplementalγ-aminobutyric acid(GABA)under cold stress on nitrogen metabolism in rice seedlings.Cold stress resulted in a greater increase in the transformation to NH_(4)^(+)by nitrate reductase(NR)in roots,it further resulted in lower levels of NO_(3)^(-)content in roots,weakened glutamine glutamate(GOGAT/GS)pathway and elevated glutamate dehydrogenase(GDH)pathway of rice seedlings.Whereas,compared with cold stress,supplementation of GABA(2.5 mmol·L^(-1))could increase relative water content(79.43%)and biomass(34.15%)of rice seedlings.GABA could act as an amplifier of stress signal conduction/transduction to increase NR activity and promote NO_(3)^(-)assimilation in leaves.In addition,GABA elicited the Ca^(2+)signaling pathway which could promote the GDH pathway and GABA shunt,increase the activities of GS and GDH,and the expression of OsGAD2 and OsGDH family.The GABA might increase the ratio of the Glu family and avoid NH4+toxicity in order to raise the concentration of organic compounds and alleviate the harmful consequences of cold stress.Based on these observations,this study proposed that GABA mediated cold tolerance in rice seedlings by activating Ca^(2+)burst and subsequent crosstalk among Ca^(2+)signaling,GDH pathway and GABA shunt.展开更多
基金Supported by Young Scientifi c Fund of Heilongjiang Province (QC2010093)Project of Daqing Scientifi c Program (sggh2009-029)
文摘A developed method was used for the enhancement of arachidonic acid production by M. isabellina. An orthogonal, rotatable and central composite design was applied to determine the optimum conditions for protoplast regeneration mutagenesis. The results showed that a commixture enzyme （cellulase and glusulase） at the concentration of 4%, enzymolysis temperature at 30℃ and enzymolysis time on 7.5 h were the optimal conditions, in which the lethality of M. isabellina spores was 78.4%. After mutagenesis and re-screenings, M. isabellina mutant Y-69 was obtained. GC analysis showed that the yield of arachidonic acid by Y-69 （2.92 g. L-1） was 3.56 times higher than that of the wild-type strain （0.82 g.L-1）. Pass generation tests showed that the properties of Y-69 by mutation were readily inherited.
基金Supported by the National Natural Science Foundation of China(31171657)Heilongjiang Youth Science Foundation(QC2010093)+1 种基金Heilongjiang Natural Science Foundation(20100481037)Key Projects on Ministry of Education in Heilongjiang(12511Z022)
文摘Arachidonic acid （AA or ARA）, an essential to-6 polyunsaturated fatty acid （PUFA）, can be produced by Mortierella isabellina. Mutagenesis on Mortierella isabellina As3.3410 was induced to raise ARA production. The mutant strain of YZ-124 had the highest ARA of 4.72 g. L-1, which was 5.5 times higher than that of the original strain 3.3410. mRNA expression level of △ 6- desaturase was determined in five different kinds of ARA-producing Mortierella isabellina after cultured for 7 days, and in the mutant strain YZ-124 over a 3-8 day time-course. In addition, the desaturase activity and ARA content were measured at the selected time points. The lowest expression of △6-desaturase was observed in the original strain and the highest expression in the mutant strain YZ-124, which increased with increasing time in culture. Furthermore, a positive correlation was observed between the expression levels of △6-desaturase and ARA content. Based on this, △6-desaturase played a significant role in ARA synthesis pathway in Mortierella isabellina.
文摘Objective Traditional Chinese medicine(TCM)constitutes a valuable cultural heritage and an important source of antitumor compounds.Poria(Poria cocos(Schw.)Wolf),the dried sclerotium of a polyporaceae fungus,was first documented in Shennong’s Classic of Materia Medica and has been used therapeutically and dietarily in China for millennia.Traditionally recognized for its diuretic,spleen-tonifying,and sedative properties,modern pharmacological studies confirm that Poria exhibits antioxidant,anti-inflammatory,antibacterial,and antitumor activities.Pachymic acid(PA;a triterpenoid with the chemical structure 3β-acetyloxy-16α-hydroxy-lanosta-8,24(31)-dien-21-oic acid),isolated from Poria,is a principal bioactive constituent.Emerging evidence indicates PA exerts antitumor effects through multiple mechanisms,though these remain incompletely characterized.Neuroblastoma(NB),a highly malignant pediatric extracranial solid tumor accounting for 15%of childhood cancer deaths,urgently requires safer therapeutics due to the limitations of current treatments.Although PA shows multi-mechanistic antitumor potential,its efficacy against NB remains uncharacterized.This study systematically investigated the potential molecular targets and mechanisms underlying the anti-NB effects of PA by integrating network pharmacology-based target prediction with experimental validation of multi-target interactions through molecular docking,dynamic simulations,and in vitro assays,aimed to establish a novel perspective on PA’s antitumor activity and explore its potential clinical implications for NB treatment by integrating computational predictions with biological assays.Methods This study employed network pharmacology to identify potential targets of PA in NB,followed by validation using molecular docking,molecular dynamics(MD)simulations,MM/PBSA free energy analysis,RT-qPCR and Western blot experiments.Network pharmacology analysis included target screening via TCMSP,GeneCards,DisGeNET,SwissTargetPrediction,SuperPred,and PharmMapper.Subsequently,potential targets were predicted by intersecting the results from these databases via Venn analysis.Following target prediction,topological analysis was performed to identify key targets using Cytoscape software.Molecular docking was conducted using AutoDock Vina,with the binding pocket defined based on crystal structures.MD simulations were performed for 100 ns using GROMACS,and RMSD,RMSF,SASA,and hydrogen bonding dynamics were analyzed.MM/PBSA calculations were carried out to estimate the binding free energy of each protein-ligand complex.In vitro validation included RT-qPCR and Western blot,with GAPDH used as an internal control.Results The CCK-8 assay demonstrated a concentration-dependent inhibitory effect of PA on NB cell viability.GO analysis suggested that the anti-NB activity of PA might involve cellular response to chemical stress,vesicle lumen,and protein tyrosine kinase activity.KEGG pathway enrichment analysis suggested that the anti-NB activity of PA might involve the PI3K/AKT,MAPK,and Ras signaling pathways.Molecular docking and MD simulations revealed stable binding interactions between PA and the core target proteins AKT1,EGFR,SRC,and HSP90AA1.RT-qPCR and Western blot analyses further confirmed that PA treatment significantly decreased the mRNA and protein expression of AKT1,EGFR,and SRC while increasing the HSP90AA1 mRNA and protein levels.Conclusion It was suggested that PA may exert its anti-NB effects by inhibiting AKT1,EGFR,and SRC expression,potentially modulating the PI3K/AKT signaling pathway.These findings provide crucial evidence supporting PA’s development as a therapeutic candidate for NB.
文摘Herein,a one-pot chemical reduction method was reported to prepare folic acid(FA)-stabilized silver nanoclusters(FA@Ag NCs),in which FA,hydrazine hydrate,and silver nitrate were used as capping agent,reducing agent,and precursor,respectively.Several technologies were employed to investigate the structures and optical properties of FA@Ag NCs,including transmission electron microscopy(TEM),X-ray photoelectron spectrometer(XPS),Fourier transform infrared spectrometer(FTIR),X-ray diffractometer(XRD),fluorescence spectrometer,and ultraviolet visible absorption spectrometer.FA@Ag NCs were suggested to be highly dispersed and spherical with a size of around 2.8 nm.Moreover,the maximum excitation and emission wavelengths of FA@Ag NCs were 370 and 447 nm,respectively.Under the optimal detection conditions,FA@Ag NCs could be used to effectively detect malachite green with the linear detection range of 0.5-200μmol·L^(-1).The detection limit was 0.084μmol·L^(-1).The fluorescence-quenching mechanism was ascribed to the static quenching.The detection system based on FA@AgNCs was successfully used for the detection of malachite green in actual samples with good accuracy and reproducibility.
文摘In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were investigated.The results showed that the three materials had satisfactory compatibility in the composite film.Addition of EC and zein effectively improved the mechanical properties,thermodynamic properties,surface hydrophilicity,oxygen permeability,and degradation properties of PLA films.When the ratio of PLA to EC was 3:7,the tensile strength and elongation at break reached maximum values of 16.6 MPa and 30.5%,respectively.Moreover,under different conditions,the composite film exhibited better degradability than the PLA film.The composite film with a 3:7 ratio of PLA to EC had the best performance,with a degradation rate of 21.75%after 84 days.Chilled fresh meat wrapped with the composite film showed significantly improved antioxidant,antibacterial,and water-holding properties.
基金Supported by Hainan Provincial Natural Science Foundation of China(322MS134)。
文摘This study aimed to investigate the effects of dietary guanidinoacetic acid on growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.Total 48042-day-old female ducks were randomly divided into four groups with six replicates and 20 ducks per replicate and fed the basal diet to the control group.The experimental groups were fed the basal diet with 400,600 and 800 mg·kg^(-1) guanidinoacetic acid,respectively.The trial lasted 48 days.Compared with the control group,(1)the body weight at 90 days and average daily gain were increased(P<0.05),the feed conservation ratio was decreased(P<0.05);(2)the dressing percentage and breast muscle percentage were increased(P<0.05);(3)the total amino acid content,polyunsaturated fatty acids to monounsaturated fatty acids ratio were increased(P<0.05)in breast and thigh muscles;(4)activities of superoxide dismutase,catalase and glutathione peroxidase enzyme were increased(P<0.05)in thigh muscles;(5)the relative expressions of superoxide dismutase 1,glutathione peroxidase 1,and catalase were significantly increased(P<0.05)in the liver.In this study,the optimum dosage of 600 mg·kg^(-1) guanidinoacetic acid improved the growth performance,meat quality,antioxidant activity,and antioxidant-related gene expression in ducks.
基金supported by the Natural Science Foundation of Hunan Province(2021JJ31089)the Scientific Research Project of Health Commission of Hunan Province(202203104548),China。
文摘Objective:The neurotoxicity of carbon monoxide(CO)to the central nervous system is a key pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning(DEACMP).Our previous study found that retinoic acid(RA)can suppress the neurotoxic effects of CO.This study further explores,in vivo and in vitro,the molecular mechanisms by which RA alleviates CO-induced central nervous system damage.Methods:A cytotoxic model was established using the mouse hippocampal neuronal cell line HT22 and primary oligodendrocytes exposed to CO,and a DEACMP animal model was established in adult Kunming mice.Cell viability and apoptosis of hippocampal neurons and oligodendrocytes were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay and Annexin V/propidium iodide(PI)double staining.The transcriptional and protein expression of each gene was detected using real time fluorescence quantitative PCR(RT-qPCR)and Western blotting.Long noncoding RNA(lncRNA)SNHG15 and LINGO-1 were knocked down or overexpressed to observe changes in neurons and oligodendrocytes.In DEACMP mice,SNHG15 or LINGO-1 were knocked down to assess changes in central nervous tissue and downstream protein expression.Results:RA at 10 and 20μmol/L significantly reversed CO-induced apoptosis of hippocampal neurons and oligodendrocytes,downregulation of SNHG15 and LINGO-1,and upregulation of brain-derived neurotrophic factor(BDNF)and tyrosine kinase receptor B(TrkB)(all P<0.05).Overexpression of SNHG15 or LINGO-1 weakened the protective effect of RA against CO-induced cytotoxicity(all P<0.05).Knockdown of SNHG15 or LINGO-1 alleviated CO-induced apoptosis of hippocampal neurons and oligodendrocytes and upregulated BDNF and TrkB expression levels(all P<0.05).Experiments in DEACMP model mice showed that knockdown of SNHG15 or LINGO-1 mitigated central nervous system injury in DEACMP(all P<0.05).Conclusion:RA alleviates CO-induced apoptosis of hippocampal neurons and oligodendrocytes,thereby reducing central nervous system injury and exerting neuroprotective effects.LncRNA SNHG15 and LINGO-1 are key molecules mediating RA induced inhibition of neuronal apoptosis and are associated with the BDNF/TrkB pathway.These findings provide a theoretical framework for optimizing the clinical treatment of DEACMP and lay an experimental foundation for elucidating its molecular mechanisms.
基金Project(U2067217)supported by the National Natural Science Foundation of ChinaProject(SASTIND)supported by the State Administration of Science,Technology and Industry for National Defense,ChinaProject(2020M683572)supported by China Postdoctoral Science Foundation。
文摘The influence of grain size or grain refinement on the corrosion of Zr alloy is clarified by employing a series of electrochemical analyses and characterization techniques.The corrosion resistance,as a function of exposure time,F−concentration,and solution temperatures,of Zr alloys with different grain sizes is ascertained.The results confirm that refining the grain size can effectively enhance the short-time corrosion properties of Zr alloy in HNO_(3) with F−.The fine grained Zr alloy(~10μm in diameter)consistently exhibits a lower corrosion current density,ranging from 18%to 46%lower than that of the coarse-grained Zr alloy(~44μm).The enhanced corrosion resistance is attributed to the high density grain boundaries,which promote oxide stability,and accelerate the creation of the protective layer.The high corrosion rate and pseudo-passivation behavior of Zr alloys in fluorinated nitric acid originate from the accelerated“dissolution-passivation”of the oxide film.However,the grain refinement does not provide enduring anti-corrosion for Zr alloys.To meet the operation of spent fuel reprocessing,additional systematic efforts are required to evaluate the long term effect of grain refinement.
基金Project(2023RC3066)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2023JJ50079)supported by the Hunan Provincial Natural Science Foundation,China。
文摘Carbonized melamine foam has been recognized as a promising material for microwave absorption due to its exceptional thermal stability,lightweight,and remarkable dielectric properties.In this study,we investigated the impact of nitric acid oxidation on the surface of carbonized melamine foam and its microwave absorption properties.The treated foam exhibits optimal reflection loss of−21.51 dB at 13.20 GHz,with an effective absorption bandwidth of 7.04 GHz.The enhanced absorption properties are primarily attributed to the strengthened dielectric loss,improved impedance matching,and increased polarization losses resulting from the oxidized surfaces.This research demonstrates a promising new approach for research into surface treatments to improve the performances of microwave absorbers.
基金supported by National Natural Science Foundation of China(No.32160615).
文摘Background Verticillium dahliae,a soil-borne fungi,can cause Verticillium wilt,and seriously diminish the yield and quality of cotton.However,the pathogenic mechanism of V.dahliae is complex and not clearly understood at the moment.This study aimed to identify the high-affinity nicotinic acid transporter genes in V.dahliae.The gene expression profiles in V.dahliae following sensing of root exudates from susceptible and resistant cotton varieties were analyzed.The function of VdNAT1 in the pathogenic process of V.dahliae was studied using the tobacco rattle virus(TRV)-based host-induced gene silencing(HIGS)technique.Results Eight high-affinity nicotinic acid transporter genes were identified from V.dahliae through the bioinformatics method.Each protein contains a conserved major facilitator superfamily(MFS)domain,which belongs to the MFS superfamily.Evolutionary relationship analysis revealed that all 8 genes belong to the anion:cation symporter(ACS)subfamily.All proteins have transmembrane domains,ranging from 7 to 12.The expression levels of most VdNAT genes were significantly increased after induction by root exudates from susceptible cotton varieties.Silencing VdNAT1 gene by HIGS significantly inhibited the accumulation of fungal biomass in cotton plants,and alleviated the disease symptoms of cotton.Conclusions Eight VdNAT genes were identified from V.dahliae,and most VdNAT genes was up-regulated after induced by root exudates from susceptible cotton variety.In addition,VdNAT1 is required for the pathogenicity of V.dahliae.Overall,these findings will facilitate the pathogenic molecular mechanism of V.dahliae and provide candidate genes.
基金supported by the Joint Fund for New Medicine of the University of Science and Technology of China(YD9100002029).
文摘Objective:Oleic acid,a subtype of monounsaturated fatty acid(MUFA),is present in abundance in certain edible oils,particularly olive oils.Epidemiological evidence concerning dietary oleic acid intake and the long-term risk of mortality is lacking.This study aimed to evaluate the associations of the dietary intake of oleic acid and other specific subtypes of MUFAs,olive oil,and other vegetable oils with cardiovascular disease(CVD)and all-cause mortality.Methods:This prospective cohort study included adults aged 40 years or older who participated in the included U.S.adults National Health and Nutrition Examination Survey(NHANES).Dietary MUFA intake was assessed via 24-h dietary recall interviews in NHANES 1999–2018,and the consumption of olive oil and other vegetable oils was assessed via a food frequency questionnaire in NHANES 2003–2006.Deaths and underlying causes of death were ascertained by linkage to the National Death Index through December 31,2019.Weighted Cox proportional hazards regression models were used to estimate the hazard ratio(HR)and 95%CIs.Results:Dietary intake of total MUFAs and oleic acid was associated with a lower risk of CVD mortality,with HRs(95%CI)of 0.62(0.39–0.99)and 0.61(0.39–0.97),respectively.Total MUFA and oleic acid intake were inversely associated with all-cause mortality;the multivariable-adjusted HRs were 0.77(95%CI:0.60–0.99)and 0.78(95%CI:0.62–0.99),respectively.There was no significant association between palmitoleic acid intake and all-cause mortality.The habitual consumption of olive oil,but not the consumption of other vegetable oils,was inversely associated with the risk of cardiovascular mortality.In the joint association analysis,the HRs(95%CI)of cardiovascular mortality were 0.36(0.19–0.69)for people who exclusively consumed olive oil,0.59(0.27–1.32)for people who consumed both olive oil and other vegetable oils,and 0.73(0.46–1.14)for people who exclusively consumed other vegetable oils compared with people who never consumed vegetable oils.Conclusions:In a U.S.nationally representative prospective cohort,higher dietary oleic acid intake and olive oil consumption were associated with a lower risk of cardiovascular mortality.
文摘Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been constructed hydrothermally using H_(2)cpna(5-(4-carboxyphenoxy)nicotinic acid),dpea(1,2-di(4-pyridyl)ethane),dpey(1,2-di(4-pyridyl)ethylene),and zinc,cobalt,and nickel chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the triclinic system,space group P1.Compounds 1-3 show 2D layer structures.The catalytic activities in the Knoevenagel condensation reaction of these compounds were investigated.Compounds 1 and 2 exhibit effective catalytic activities in the Knoevenagel condensa-tion reaction at room temperature.For this reaction,various parameters were optimized,followed by the investiga-tion of the substrate scope.CCDC:2335676,1;2335677,2;2335678,3.
文摘Herein,a layered chiral coordination polymer,[Cd2(D‑cam)_(2)(2,2′‑bipy)_(2)]_(n)(Cd‑CP),was synthesized using a solvothermal method with camphoric acid(D‑H_(2)cam),2,2′‑bipyridine(2,2′‑bipy)and Cd^(2+),and Tb^(3+)@Cd‑CP was in‑situ synthesized introducing Tb^(3+)ions.The fluorescence experiments revealed that compared to Cd‑CP,Tb^(3+)@Cd‑CP exhibited ultra‑high fluorescence performance.The luminescence sensing performance demonstrated that Tb^(3+)@Cd‑CP could distinguish R/S‑propylene glycol(R/S‑PG)by fluorescence responses,with fluorescence quenching constant of 5.3×10^(3)and 2.0×10^(3)L·mol^(-1)respectively and the enantioselectivity factor(α)of 2.65.Moreover,Tb^(3+)@Cd‑CP demonstrated limits of detection of 9.3 and 19.0μmol·L^(-1)for R‑PG and S‑PG,respectively,and showed good reproducibility.
基金supported by Natural Science Foundation of Shandong Province(ZR2022MB049)National Natural Science Foundation of China(22078174)。
文摘Biomass-derived platform molecules,such as furfural,are abundant and renewable feedstock for valuable chemical production.It is critical to synthesize highly efficient photocatalysts for selective oxidation under visible light.The Er@K-C_(3)N_(4)/UiO-66-NH_(2) catalyst was synthesized using a straight-forward hydrothermal technique,and exhibited exceptional efficiency in the photocatalytic oxidation of furfural to furoic acid.The catalyst was thoroughly characterized,confirming the effective adjustment of the band gap energy of Er@K-C_(3)N_(4)/UiO-66-NH_(2).Upon the optimized reaction conditions,the conversion rate of furfural reached 89.3%,with a corresponding yield of furoic acid at 79.8%.The primary reactive oxygen species was identified as·O_(2)^(-) from ESR spectra and scavenger tests.The incorporation of Er and K into the catalyst enhanced the photogenerated carriers transfer rate,hence increasing the separating efficiency of photogenerated electron-hole pairs.This study expands the potential applications of rare earth element doped g-C_(3)N_(4) in the photocatalytic selective oxidation of furfurans.
基金The Key Research and Development Program of Zhejiang Province(2021C01003)National Natural Science Foundation of China(52025011,51971202,51872260 and 52171019)The Zhejiang Provincial Natural Science Foundation of China(LD19B030001,Z4080070 and LR23B030004)。
文摘Based on the criteria for additional surface acidity generation in composite oxides and composite fluorides proposed by Tanabe and Kemnitz et al.A hypothesis for the origin of additional surface acidity in solid composites with the same metal cations is proposed.The surface acidsites of We analyze three types of solid composite systems,that is,CrF_(3)/Cr_(2)O_(3),MgF_(2)/MgO,and ZnF_(2)/ZnO,is systematically analyzed,which agrees with experimental results.Accordingly,the origin of additional surface acidity in these solid composites is reasonably explained,and the types of acidic sites are also predicted.
基金Project(42476209)supported by the National Natural Science Foundation of ChinaProject(2023GXNSFBA026252)supported by the Youth Science Foundation of Guangxi Province,China+2 种基金Project(ZR2023MD024)supported by the Natural Science Foundation of Shandong Province,ChinaProject(JC22022104)supported by the Natural Science Foundation of Nantong,ChinaProject(2023VEA0007)supported by the Chinese Academy of Sciences President’s International Fellowship Initiative。
文摘The corrosion behavior of the acidophilic sulfur-oxidizing microorganism(ASOM)Acidithiobacillusthiooxidans(A.thiooxidans)on mortar was investigated for changes of medium and mortar,as well as for weight lossand surface morphology of mortar specimens.Weight loss analysis showed that mortar weight was reduced by(15.1±2.2)%after 56 d.Morphological surface analysis of mortar specimens showed weakly structured fibrous substances with2−100μm in size.The pH variations of the mortar surface and medium indicated that biogenic sulfuric acid had beenproduced by A.thiooxidans.The results prove that A.thiooxidans accelerated concrete corrosion and caused concretefailure.
文摘OBJECTIVE To investigate whether aldo-keto reductases(AKRs)can act as a nitrore⁃ductase(NR)and bioactivate aristolochic acidⅠ(AA-Ⅰ)to produce AA-Ⅰ-DNA adducts.METHODS①Human-induced hepatocytes(hiHeps)and human bladder RT4 cells were used as tool cells and treated with AA-Ⅰ0,0.5,1.0 and 2μmol·L^(-1)for 24 h.Cell viability was detected using the CCK-8 method,and the half maximal inhibition concentration(IC_(50))was calculated using the CCK-8 method and the level of DNA adduct production was calculated.②hiHeps and RT4 cells were treated with AKR inhibitor luteotin(0,5,10 and 25μmol·L^(-1))+AA-Ⅰ0.2 and 1.0μmol·L^(-1)for 24 h,respectively,and the levels of DNA adducts were detected by a liquid chromatography-tandem mass spectrometer(LC-MS/MS).③hiHeps cells were incubated with 80 nmol·L^(-1)small interfering RNAs(si-AKRs)for 48 h and treated with AA-Ⅰ1.0μmol·L^(-1)for 24 h.Real-time qualitative PCR(RT-qPCR)method was used to detect the mRNA expression of AKRs gene and LC-MS/MS technology was used to investigate the effect of specific AKR gene knockdown on DNA adduct levels.④500 nmol·L^(-1)human AKR recombinant proteins AKR1A1 and AA-Ⅰwere incubated in vitro under anaerobic conditions and the formation of AA-Ⅰ-DNA adducts was detected.RESULTS①The IC_(50)of AA-Ⅰto hiHeps and RT4 cells was 1.9 and 0.42μmol·L^(-1),respec⁃tively.The level of DNA adduct production of the two cell lines was significantly different(P<0.01).②Luteolin≥5μmol·L^(-1)significantly inhibited the production of AA-Ⅰ-DNA adducts in both cells(P<0.05),and there was a concentration-dependent effect in hiHeps cells(P<0.01,R=0.84).③In the AKR family,the knockdown of AKR1A1 gene up to 80%inhibited the generation of AA-Ⅰ-DNA adducts by 30%-40%.④The AA-Ⅰ-DNA adducts were detected in the incubation of recombinant protein AKR1A1 and AA-Ⅰunder anaerobic conditions in vitro,approximately 1 adduct per 107 nucleotides.CONCLU⁃SION AKR1A1 is involved in AA-Ⅰbioactivation,providing a reference for elucidation of the carcino⁃genic mechanism of AA-Ⅰ.
基金Projects(52101105,52373321)supported by the National Natural Science Foundation of ChinaProject(2023-PY03)supported by the IMR Innovation Fund,ChinaProject(CNNC-LCKY-202274)supported by the LingChuang Research Project of China National Nuclear Corporation。
文摘Spent fuel reprocessing plays a pivotal role in achieving efficient recycling of nuclear fuel.Among thedifferent forms of failure encountered in spent fuel reprocessing,tribocorrosion stands out as a critical concern.Herein,the tribocorrosion behavior,as well as the corrosion behavior,of 304L stainless steel(SS)in high-temperatureconcentrated nitric acid was investigated.The results indicated that 304L SS formed a thin(1.54 nm)and stable passivefilm on the surface,imparting high resistance to nitric acid corrosion.Meanwhile,it was found that the synergistic effectbetween corrosion and wear accounted for a high total tribocorrosion weight loss of over 85%,implying the dominantrole of the synergistic effect in the tribocorrosion process.Furthermore,the wear of 304L SS in deionized water revealedboth abrasive and adhesive wear characterizations,whereas the tribocorrosion in nitric acid only exhibited abrasive wearfeature.Eventually,the tribocorrosion and corrosion models of 304L SS in hot concentrated nitric acid were proposedbased on the comprehensive experimental findings.
基金Supported by the National Natural Science Foundation of China(32301935)the Heilongjiang Province Natural Science Foundation Project(LH2020C005)+1 种基金the Postdoctoral Fund to Research Start-up of Heilongjiang Province(LBH-Q21077)Heilongjiang Province Applied Technology Research and Development Plan Project(GA20B101)。
文摘Cold stress adversely affects rice growth,particularly at the early vegetative growth stage.In higher plants,nitrogen metabolism plays a central role in amino acid metabolism,plant defense mechanisms and productivity.This report investigated the effects of cold stress and supplementalγ-aminobutyric acid(GABA)under cold stress on nitrogen metabolism in rice seedlings.Cold stress resulted in a greater increase in the transformation to NH_(4)^(+)by nitrate reductase(NR)in roots,it further resulted in lower levels of NO_(3)^(-)content in roots,weakened glutamine glutamate(GOGAT/GS)pathway and elevated glutamate dehydrogenase(GDH)pathway of rice seedlings.Whereas,compared with cold stress,supplementation of GABA(2.5 mmol·L^(-1))could increase relative water content(79.43%)and biomass(34.15%)of rice seedlings.GABA could act as an amplifier of stress signal conduction/transduction to increase NR activity and promote NO_(3)^(-)assimilation in leaves.In addition,GABA elicited the Ca^(2+)signaling pathway which could promote the GDH pathway and GABA shunt,increase the activities of GS and GDH,and the expression of OsGAD2 and OsGDH family.The GABA might increase the ratio of the Glu family and avoid NH4+toxicity in order to raise the concentration of organic compounds and alleviate the harmful consequences of cold stress.Based on these observations,this study proposed that GABA mediated cold tolerance in rice seedlings by activating Ca^(2+)burst and subsequent crosstalk among Ca^(2+)signaling,GDH pathway and GABA shunt.
