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哈茨木霉菌活性物质harzianic acid的异源合成及其抑菌机制研究
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作者 李心芃 宋瑞轲 +2 位作者 高琦 沈标 张建 《南京农业大学学报》 北大核心 2025年第4期880-891,共12页
[目的]本文旨在分离、纯化、鉴定和异源合成harzianic acid,并研究其对病原真菌的抑制机制。[方法]插入突变获得产黄色物质突变株哈茨木霉菌(Trichoderma harzianum)NJAU 5688,结合液相色谱-质谱联用技术(HPLC-MS)、核磁共振(NMR)等数... [目的]本文旨在分离、纯化、鉴定和异源合成harzianic acid,并研究其对病原真菌的抑制机制。[方法]插入突变获得产黄色物质突变株哈茨木霉菌(Trichoderma harzianum)NJAU 5688,结合液相色谱-质谱联用技术(HPLC-MS)、核磁共振(NMR)等数据确定主要成分为harzianic acid;利用同源重组异源表达的方法提高harzianic acid的产量;利用平板试验研究harzianic acid抑制病原菌的能力;利用转录组研究harzianic acid对Fusarium oxysporum f.sp.cubense 4(Foc4)的拮抗机制,研究harzianic acid对Foc4细胞膜的影响。[结果]与野生型Trichoderma harzianum NJAU 4742相比,NJAU 5688的水溶代谢产物对病原真菌具有更强的抑制作用;HPLC-MS、NMR等数据分析确定该突变株的水溶代谢产物主要化合物为harzianic acid;在构巢曲霉(Aspergillus nidulans)A1145中同源重组,异源合成后harzianic acid产量可达19.66 mg·L^(-1)。平板试验表明,harzianic acid对病原真菌的抑制作用具有显著浓度依赖性。用harzianic acid处理后Foc4菌丝中关于质膜和相关成分富集的基因最为显著,用100 mg·L^(-1) harzianic acid处理Foc4胞外溶液的D 260值(0.443)约为对照组(0.232)的1.91倍,表明harzianic acid可能破坏了Foc4的细胞膜。[结论]鉴定突变子NJAU 5688合成了抑菌物质harzianic acid,在A1145中实现异源合成,产量达到19.66 mg·L^(-1);结合转录组和核酸检测,100 mg·L^(-1) harzianic acid破坏Foc4菌丝细胞膜,抑制Foc4生长。 展开更多
关键词 哈茨木霉 harzianic acid 异源合成 转录组分析 细胞膜
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Effective detection of malachite green by folic acid stabilized silver nanoclusters
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作者 CAI Zhifeng WU Ying +3 位作者 LI Ya'nan MENG Guiyu MIAO Tianyu ZHANG Yihao 《无机化学学报》 北大核心 2025年第5期983-993,共11页
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
关键词 fluorescence probe silver nanoclusters folic acid malachite green static quenching
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Preparation of Biodegradable Polylactic Acid/Ethyl Cellulose/Zein Composite Film and Its Effect on the Preservation of Chilled Fresh Meat
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作者 ZHOU Ling YU Ya +8 位作者 YUAN Mengting WU Dongxu CHEN Ya LIU Yanan SU Jingjing CHEN Sihan WANG Juhua SHENG Bulei XUE Xiuheng 《食品科学》 北大核心 2025年第15期324-337,共14页
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
关键词 biodegradable film polylactic acid ethyl cellulose ZEIN chilled fresh meat PRESERVATION
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Effects of Dietary Guanidinoacetic Acid on Growth Performance,Meat Quality,Antioxidant Activity,and Antioxidant-related Gene Expression in Ducks
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作者 Yu Xilong Lin Yu +2 位作者 Dou Renkai Xu Liangmei Wu Hongzhi 《Journal of Northeast Agricultural University(English Edition)》 2025年第1期1-18,共18页
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
关键词 guanidinoacetic acid carcass characteristics fatty acid amino acid antioxidant activity
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Effect of grain refinement on the corrosion behavior of Zr alloys in fluorinated nitric acid
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作者 XIE Yu-fei WANG Yan-fei +4 位作者 SONG Gui-kang YU Qi-fan LU Xiao-peng LI Jin-shan WANG Xian-zong 《Journal of Central South University》 2025年第5期1614-1629,共16页
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
关键词 zirconium alloys CORROSION grain size fluoride ions nitric acid
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Nitric acid oxidation treatment promoting microwave absorption performance of carbonized melamine foam
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作者 MAO Ming-zhen XIA Peng-kun +3 位作者 MA Lei HUANG Sheng-xiang GAO Xiao-hui DENG Lian-wen 《Journal of Central South University》 2025年第5期1630-1640,共11页
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
关键词 carbonized melamine foam nitric acid hydrothermal treatment interface modification microwave absorption performance
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Identification of high‑affinity nicotinic acid transporter genes from Verticillium dahliae and functional analysis based on HIGS technology
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作者 WANG Yuan KAMAU Stephen +2 位作者 SONG Shenglong ZHANG Yong ZHANG Xinyu 《Journal of Cotton Research》 2025年第2期242-255,共14页
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
关键词 Verticillium dahliae High-affinity nicotinic acid transporter gene Cotton VdNAT1 Host-induced gene silencing Major facilitator superfamily
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Dietary oleic acid intake,olive oil consumption,and risk of cardiovascular and all-cause mortality 被引量:2
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作者 Huihui Lu Buyun Liu +3 位作者 Wenjun Fu Kaiwen Ji Shuang Rong Wei Bao 《中国科学技术大学学报》 CAS CSCD 北大核心 2024年第9期45-53,69,70,共11页
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
关键词 oleic acid monounsaturated fatty acid olive oil cardiovascular mortality all-cause mortality
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Syntheses,crystal structures,and catalytic properties of three zinc(Ⅱ),cobalt(Ⅱ)and nickel(Ⅱ)coordination polymers constructed from 5⁃(4⁃carboxyphenoxy)nicotinic acid 被引量:1
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作者 LING Weizhong CHEN Xiangyun +2 位作者 LIU Wenjing HUANG Yingkai LI Yu 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第9期1803-1810,共8页
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
关键词 coordination polymer dicarboxylic acid catalytic property Knoevenagel condensation reaction
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Chiral fluorescent sensor Tb^(3+)@Cd‑CP based on camphoric acid for the enantioselective recognition of R‑and S‑propylene glycol
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作者 LI Junying CHEN Xinyan +5 位作者 DIAO Xihui Yaseen Muhammad CHEN Chao WANG Hao QI Chuansong LI Wei 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第12期2497-2504,共8页
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
关键词 camphoric acid coordination polymer ENANTIOSELECTIVITY propylene glycol
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Enhancing photo-generated carriers transfer of K-C_(3)N_(4)/UiO-66-NH_(2) with Er doping for efficient photocatalytic oxidation of furfural to furoic acid
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作者 WANG Haocun LIU Lingtao +1 位作者 BIAN Junjie LI Chunhu 《燃料化学学报(中英文)》 EI CAS CSCD 北大核心 2024年第11期1617-1628,共12页
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
关键词 FURFURAL furoic acid selective catalytic oxidation MOFS carbon nitride
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Influencing factors analysis of hard limestone reformation and strength weakening under acidic effect
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作者 HOU Ming-xiao HUANG Bing-xiang +2 位作者 ZHAO Xing-long JIAO Xue-jie ZHENG Chen-yang 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2446-2466,共21页
Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way t... Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines. 展开更多
关键词 hard roof acidic effect structural reformation strength weakening influencing factors
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A Hypothesis Regarding the Origin of Additional Surface Acidity in Solid Complexes with Same Metal Cations
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作者 SHAO Bo TONG Chaoli +5 位作者 WANG Jiaqian HAN Zhongkang ZHANG Yan GE Wenfeng WANG Yong YANG Hangsheng 《材料科学与工程学报》 CAS CSCD 北大核心 2024年第5期718-722,共5页
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
关键词 Surface acidity Solid composite Local charge imbalance
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Investigation of mortar corrosion by an acidophilic sulfur-oxidizing microorganism A.thiooxidans
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作者 WANG Dong-sheng FENG Chao +4 位作者 GUAN Fang SAND Wolfgang KRISHNAMURTHY Mathivanan WAN Fei ZHANG Rui-yong 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第10期3423-3434,共12页
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
关键词 sulfur-oxidizing bacteria acidithiobacillus thiooxidans MORTAR CORROSION biogenic sulfuric acid mass loss
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Human AKR1A1 involves in metabolic activation of carcinogenic aristolochic acidⅠ
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作者 GAO Zhenna YOU Xinyue +6 位作者 LIU Weiying WU Jiaying XI Jing CAO Yiyi ZHANG Xiaohong ZHANG Xinyu LUAN Yang 《中国药理学与毒理学杂志》 CAS 北大核心 2024年第9期641-651,共11页
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
关键词 metabolic activation nitro-reduction aldo-keto reductase superfamily aristolochic acid
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Understanding of tribocorrosion and corrosion characteristics of 304L stainless steel in hot concentrated nitric acid solution
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作者 LIU Zheng ZHANG Lian-min +3 位作者 LIU Chen-chen TAN Ke-di MA Ai-li ZHENG Yu-gui 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第10期3657-3673,共17页
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
关键词 304L stainless steel TRIBOCORROSION CORROSION hot nitric acid mechanism model
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Effects ofγ-aminobutyric Acid on Nitrogen Metabolism in Roots and Leaves of Cold-stressed Rice(Oryza sativa L.)During Early Vegetative Growth
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作者 Jia Yan Gong Weibin +9 位作者 Ma Huimiao Liu Ge Zhang Can Liu Aixin Han Yiming Dang Yuxiang Bai Xu Wang Haixing Wu Yulong Xin Junying 《Journal of Northeast Agricultural University(English Edition)》 CAS 2024年第3期1-19,共19页
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
关键词 cold stress γ-aminobutyric acid RICE nitrogen metabolism
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Designing catalysts to formic acid oxidation reaction:From nanoscale to single atoms
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作者 GONG Jia-xin HU Shou-yao XIONG Yu 《Journal of Central South University》 CSCD 2024年第12期4586-4600,共15页
Formic acid oxidation reaction(FAOR),as the anodic reaction in direct formic acid fuel cells,has attracted much attention but increasing the mass activity and stability of catalysts still face a bottleneck to meet the... Formic acid oxidation reaction(FAOR),as the anodic reaction in direct formic acid fuel cells,has attracted much attention but increasing the mass activity and stability of catalysts still face a bottleneck to meet the requirements of practical applications.In the past decades,researchers developed many strategies to fix these issues by improving the structure of catalysts and the newly raised single atom catalysts(SACs)show the high mass activity and stability in FAOR.This review first summarized the reaction mechanism involved in FAOR.The mass activity as well as stability of catalysts reported in the past five years have been outlined.Moreover,the synthetic strategies to improve the catalytic performance of catalysts are also reviewed in this work.Finally,we proposed the research directions to guide the rational design of new FAOR catalysts in the future. 展开更多
关键词 formic acid oxidation reaction nanosized catalysts single atom catalysts synthetic strategy
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汉麻仁多肽对高尿酸血症斑马鱼的降尿酸作用及其氨基酸序列分析 被引量:1
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作者 魏连会 董艳 +5 位作者 石杰 李国巍 张正海 姬妍茹 杨庆丽 潘静 《中国油脂》 北大核心 2025年第2期57-62,共6页
为促进汉麻仁多肽在功能食品及特医食品领域的应用,利用斑马鱼模型研究汉麻仁多肽的降尿酸作用及可能的机制,分析降尿酸活性肽组分的氨基酸序列。采用10mmol/L尿酸酶活性抑制剂氧嗪酸钾和50μmol/L尿酸合成前体黄嘌呤钠盐饲喂斑马鱼20h... 为促进汉麻仁多肽在功能食品及特医食品领域的应用,利用斑马鱼模型研究汉麻仁多肽的降尿酸作用及可能的机制,分析降尿酸活性肽组分的氨基酸序列。采用10mmol/L尿酸酶活性抑制剂氧嗪酸钾和50μmol/L尿酸合成前体黄嘌呤钠盐饲喂斑马鱼20h,建立斑马鱼高尿酸血症模型。以别嘌呤醇为阳性对照,以不同质量浓度的汉麻仁多肽饲喂斑马鱼,测定斑马鱼的尿酸荧光强度、次黄嘌呤鸟嘌呤磷酸核糖基转移酶(HPRT1)和有机阴离子转运蛋白(OAT1)基因的mRNA表达,利用液相色谱-串联质谱技术对降尿酸活性肽组分氨基酸序列进行分析。结果表明:汉麻仁多肽能够通过上调HPRT1和OAT1基因表达,有效降低高尿酸斑马鱼的尿酸水平;汉麻仁多肽活性组分中丰度较高的8个峰对应的肽段分子质量分别为499.23、578.24、628.27、653.29、715.31、918.43、982.41、1128.49Da,其氨基酸序列分别为PGTPE、MPDDV、TTSYTG、TPHWN、NNGDSPL、DDFNPRR、NPHDEFQP、YHSYLCKTD。综上,汉麻仁多肽可作为功能性成分用于降尿酸相关功能食品和保健品的开发。 展开更多
关键词 汉麻仁多肽 斑马鱼 高尿酸血症 降尿酸 氨基酸序列
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Identification of Active Components in Humic Acids Affecting Tomato Germination
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作者 Wei Shiping Shi Peihua +4 位作者 Wang Quanzhi Wang Yuanhua Zhao Jiayin Yin Kaijun Wu Meng 《Journal of Northeast Agricultural University(English Edition)》 CAS 2024年第4期1-15,共15页
Humic acids can promote the germination of many vegetable seeds,but the key active components remain unclear.This study utilized nutrient content,cross polarization magic angle spin ^(13)C solid magnetic resonance(CPM... Humic acids can promote the germination of many vegetable seeds,but the key active components remain unclear.This study utilized nutrient content,cross polarization magic angle spin ^(13)C solid magnetic resonance(CPMAS-^(13)C-NMR)and ultra-high performance liquid chromatography-mass spectrometry(UHPLC-MS)to characterize the chemical components of humic acids.Tomato seed germination index(GI)was determined with the goal of screening the key active components of humic acids.Humic acids had a significantly higher nutrient content,except for the total nitrogen(TN)and the total phosphorus(TP)contents.Humic acids had a higher content of O-CH_(3)/NCH,aromatic C-O and carbonyl C compared to weathered coal,with significantly lower anomeric C,aromatic C and O-alkyl C/alkyl C.There were 611 different compounds identified among the test materials using UHPLC-MS.Humic acids also had a significantly higher GI(158.0%and 153.1%)than weathered coal(85.5%).The organic matter(OM),TP and available potassium(AK)contents in humic acids were significantly positively correlated with GI,and available phosphorus(AP)was significantly negatively correlated.Among the carbon components,O-CH3/NCH,aromatic C-O and O-alkyl C/alkyl C were significantly positively correlated with GI,while anomeric C was significantly negatively correlated.Furthermore,among the top 10 positive and five negative correlation compounds,lipids and lipid-like molecules[armexifolin,boviquinone 4,3-methyladipic acid,lxocarpalactone A,monic acid,DG(20:1(11Z)/18:4(6Z,9Z,12Z,15Z)/0:0),and brassinolide]and organic acids and derivatives(N-acetylglutamic acid,8-hydroxy-5,6-octadienoic acid,acetyl-L-tyrosine,and hydroxyprolyl-methionine)in humic acids might be crucial active components for improving tomato seed germination.The results provided direct evidence for the identification of bioactive molecules of humic acids,and a scientific basis for the precise utilization of bioactive molecular components of humic acids in sustainable agricultural development. 展开更多
关键词 humic acid cross polarization magic angle spin 13C solid magnetic resonance(CPMAS-13C-NMR) ultra-high performance liquid chromatography-mass spectrometry(UHPLC-MS) germination index(GI) active component
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