One feature of Golding' s works is to reveal the theme-the evil nature of man,through the characters' mystical experience.This is obvious in Darkness Visible and Lord of the Flies.This paper tries to find out ...One feature of Golding' s works is to reveal the theme-the evil nature of man,through the characters' mystical experience.This is obvious in Darkness Visible and Lord of the Flies.This paper tries to find out the resource for the writer to use mystical experience through biological approach.展开更多
Beyond the stories,Golding spends much effort on an issue called"impotence of language"in his works,especially Lord of the Flies and Darkness Visible.Thus Golding's language view is worthwhile to researc...Beyond the stories,Golding spends much effort on an issue called"impotence of language"in his works,especially Lord of the Flies and Darkness Visible.Thus Golding's language view is worthwhile to research.With help of Lacan's theory of signifier and signified,this paper made a primary glance about Golding's language view within the two novels.展开更多
Gold ores in the Jiaozhou region of China are characterized by their abundant reserves,low grade,fine dissemination,and chal-lenges in upgrading.Froth flotation,with xanthate as the collector,is a commonly employed me...Gold ores in the Jiaozhou region of China are characterized by their abundant reserves,low grade,fine dissemination,and chal-lenges in upgrading.Froth flotation,with xanthate as the collector,is a commonly employed method for enriching auriferous pyrite from these ores.This study aimed to develop a more efficient flotation process by utilizing cavitation nanobubbles for a low-grade gold ore.Batch flotation tests demonstrated that nanobubbles significantly enhanced the flotation performance of auriferous pyrite,as evidenced by improved concentrate S and Au grades and their recoveries.The mechanisms underlying this enhancement were explored by investigat-ing surface nanobubble(SNB)formation,bulk nanobubble(BNB)attachment to hydrophobic pyrite surfaces,and nanobubble-induced agglomeration using atomic force microscopy(AFM)and focused beam reflectance measurement(FBRM).The results revealed that nan-obubble coverage on the pyrite surface is a critical factor influencing surface hydrophobicity and agglomeration.SNBs exhibited higher coverage on pyrite surfaces with increased surface hydrophobicity,flow rate,and cavitation time.Similarly,BNB attachment on pyrite surfaces was significantly increased with surface hydrophobicity and cavitation time.Enhanced surface hydrophobicity,along with higher flow rates and cavitation times,promoted pyrite particle agglomeration owing to the increased nanobubble coverage,ultimately leading to improved flotation performance.展开更多
Metal-organic framework(MOF)nanostructures have emerged as a prominent class of materials in the advancement of electrochemical sensors.The rational design of bimetallic MOF-functionalized microelectrode is of importa...Metal-organic framework(MOF)nanostructures have emerged as a prominent class of materials in the advancement of electrochemical sensors.The rational design of bimetallic MOF-functionalized microelectrode is of importance for improv-ing the electrochemical performance but still in great challenge.In this work,the bimetallic FeCo-MOF nanostructures were assembled onto a gold disk ultramicroelectrode(Au UME,5.2μm in diameter)via an in-situ electrodeposition method,which enhanced the sensitive detection of epinephrine(EP).The in-situ electrodeposited FeCo-MOF exhibited a character-istic nanoflower-like morphology and was uniformly dispersed on the Au UME.The FeCo-MOF/Au UME demonstrated excellent electrochemical performance on the detection of EP with a high sensitivity of 36.93μA·μmol^(-1)·L·cm^(-2)and a low detection limit of 1.28μmol·L^(-1).It can be attributed to the nonlinear diffusion of EP onto the ultra-micro working substrate,coupled with synergistical catalytic activity of the bimetallic Fe,Co within MOF structure.Furthermore,the FeCo-MOF/Au UME has been successful applied to the analysis of EP in human serum samples,yielding high recovery rates.These results not only contribute to the expansion of the research area of electrochemical sensors,but also provide novel insights and directions into the development of high-performance MOF-based electrochemical sensors.展开更多
Dopamine(DA)is a vital neurotransmitter,and accurate detection of its concentration is critical for both clinical diagnos-tics and neuroscience research.Due to its electrochemical activity,DA is commonly detected usin...Dopamine(DA)is a vital neurotransmitter,and accurate detection of its concentration is critical for both clinical diagnos-tics and neuroscience research.Due to its electrochemical activity,DA is commonly detected using electrochemical methods,which are favored for their simplicity,fast response time,and suitability for in vivo analysis.In this work,a highly sensitive DA electrochemical sensor was developed using an Au@MoS_(2)composite,created by modifying molybdenum disulfide(MoS_(2))nanosheets with gold nanoparticles through HAuCl_(4) reduction,and it was aimed at enhancing DA adsorption and improving detection performance.Scanning Electron Microscopy(SEM),transmission electron microscopy(TEM),Energy Dispersive Spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS)and X-ray Diffraction(XRD)confirmed the suc-cessful synthesis of Au@MoS_(2)and the uniform distribution of gold nanoparticles across the MoS_(2)nanosheets.Then,the electrochemical characterization demonstrated that the Au@MoS_(2)/GCE exhibited distinct oxidation peaks in a 10μmol·L^(-1)DA solution,with significantly enhanced electrochemical activity compared to both unmodified GCE and pristine MoS_(2).Furthermore,differential pulse voltammetry(DPV)further revealed a strong linear relationship between DA concentration and the current response in the range of 800 nmol·L^(-1)to 10μmol·L^(-1),with a low detection limit(LOD)of 78.9 nmol·L^(-1)(S/N=3).Additionally,the sensor showed excellent selectivity against other interfering substances.Moreover,the laser-induced Au@MoS_(2)(LIAu@MoS_(2)),with its abundance of negatively charged surface defects,enabled the ultra-sensitive detection of the ultra-low concentrations of DA.In conclusion,the successfully fabricated Au@MoS_(2)based sensor offers advantages such as low cost,ease of operation,and scalability,making it a promising candidate for biosensing applications due to its enhanced DA detection capabilities.展开更多
A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones w...A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.展开更多
In the Fatira(Abu Zawal)mine area,located in the northern Eastern Desert of Egypt,fieldwork and mineralogical analysis,integrated with machine learning techniques applied to Landsat-8 OLI,ASTER,and Sentinel-2 multi-sp...In the Fatira(Abu Zawal)mine area,located in the northern Eastern Desert of Egypt,fieldwork and mineralogical analysis,integrated with machine learning techniques applied to Landsat-8 OLI,ASTER,and Sentinel-2 multi-spectral imagery(MSI)data delineate gold-sulfide mineralization in altered rocks.Gold(Au)anomalies in hydrothermal breccias and quartz veins are associated with NE-oriented felsite dykes and silicified granitic rocks.Two main alteration types are identified:a pyrite-sericite-quartz and a sulfide-chlorite-carbonate assemblage,locally with dispersed free-milling Au specks.Dimensionality reduction techniques,including principal component analysis(PCA)and independent component analysis(ICA),enabled mapping of alteration types.Sentinel-2 PC125 composite images offered efficient lithological differentiation,while supervised classifications,i.e.,the support vector machine(SVM)of Landsat-8 yielded an accuracy of 88.55%and a Kappa value of 0.86.ASTER mineral indices contributed to map hydrothermal alteration mineral phases,including sericite,muscovite,kaolinite,and iron oxides.Results indicate that post-magmatic epigenetic hydrothermal activity significantly contributed to the Au-sulfide mineralization in the Fatira area,distinguishing it from the more prevalent orogenic gold deposits in the region.展开更多
Based on the properties of antimony(Sb)and arsenic(As),a method was proposed to enhance gold recovery during iron matte smelting.The impact of Sb and As on gold enhancement capture was investigated using an exclusion ...Based on the properties of antimony(Sb)and arsenic(As),a method was proposed to enhance gold recovery during iron matte smelting.The impact of Sb and As on gold enhancement capture was investigated using an exclusion method.The results demonstrated that both Sb and As significantly improved the gold recovery rate.As the Sb or As content increased,the gold recovery rate increased.The enhancement effect of Sb was better than that of As,and the optimal results were achieved through the synergistic effects of Sb and As.Under optimized conditions,the gold recovery rate reached 97.12%,whereas the gold content in the slag decreased to 1.70 g/t.Sb captured and aggregated free gold as an Au-Sb alloy,whereas As-Fe alloy also captured free gold.The growth of the gold-captured phase size enhanced the settling velocity,thereby promoting gold recovery.展开更多
The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold d...The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold deposit have been the subject of extensive discussion and analyzed by numerous scholars,a definitive conclusion remains elusive.The Jiuqu Au deposit is a significant metallogenic area in the eastern part of the Linglong gold ore field,characterized as a quartz vein-type gold deposit.Gold mineralization in the Jiuqu gold deposit is classified into four stages,primarily occurring within the Late Jurassic Linglong granite and Early Cretaceous Guojialing granodiorite.Pyrite,the primary gold-bearing mineral at the Jiuqu Gold Mine,has been present throughout the metallogenic period,is rich in a variety of trace elements and is closely related to the formation of gold ore.This study focused on evaluating pyrite from the essential metallogenic stages(Stages Ⅰ-Ⅲ)of the Jiuqu gold deposit using scanning electron microscopy(SEM),electron microprobe analysis(EMPA),laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS) sulfur isotope analysis and detection.The work aimed to reconstruct the origin of metallogenic materials and the evolution of ore-forming fluids and to restrict the genesis of the deposit.Pyrite exhibits discernible alterations in both shape and crystal structure as it progresses through its ore-forming stages.The aforementioned stages can be delineated as follows:type 1 pyrite(PyⅠ),developed in the initial ore stage,is characterized by coarse-to-medium-grained euhedral pyrite in Stage Ⅰ;type 2 pyrite(PyⅡ),developed in the second ore stage,appears during the middle stage of mineralization and is characterized by subhedral or anhedral pyrite;type 3 pyrite(PyⅢ),developed in the third ore stage,primarily occurred in the late-middle stages of mineralization.It is fragmented and coexists with various metal sulfides,including chalcopyrite,sphalerite and galena.The in situ major and elemental compositions of pyrites at Jiuqu indicate that Au,in the form of visible gold,exists in pyrites with low Au and Ag contents throughout all stages.PyⅠ had lower Pb,Bi,Co and Ni contents than those of PyⅡ.PyⅢ displayed decreased Pb,Bi,Co and Ni levels compared with PyⅡ.The δ34S values of the PyⅠ,PyⅡ and PyⅢ pyrite stages ranged from 7.19% to 8.71%,6.24% to 7.68% and 7.66% to 8.07%,respectively.According to the structural and geochemical analysis of pyrite,the ore-forming fluid of the Jiuqu gold deposit was derived from a magmatic-hydrothermal formation created by enriched lithospheric mantle-derived magma,mixing S from Precambrian metamorphic rocks.Previous studies on the H-O isotopes of quartz in the region's ores have indicated the presence of primary magma water.Additionally,studies concerning the C-O isotopes of carbonate minerals in ores have suggested that C may have originated from the mantle.Fluid migration and water-rock interaction resulted in sulfide and gold precipitation.In the Late Meosozoic,lithospheric thinning of eastern North China Craton led to up welling of astheno spheric mantle and partial melting of lithospheric mantle in the Jiaodong area.Under tectonic changes,magmatic-hydro thermal fluid migrated upward along fault structures to form a gold province.展开更多
Cyanide is the most widely used reagent in gold production processes. However, cyanide is highly toxic and poses safety haz-ards during transportation and use. Therefore, it is necessary to develop gold leaching reage...Cyanide is the most widely used reagent in gold production processes. However, cyanide is highly toxic and poses safety haz-ards during transportation and use. Therefore, it is necessary to develop gold leaching reagents that can replace cyanide. This paper intro-duces a method for synthesizing a gold leaching reagent. Sodium cyanate is used as the main raw material, with sodium hydroxide and so-dium ferrocyanide used as additives. The gold leaching reagent can be obtained under the conditions of a mass ratio of sodium cyanate,sodium hydroxide, and sodium ferrocyanide of 15:3:1, synthesis temperature of 600℃, and synthesis time of 1 h. This reagent has a goodrecovery effect on gold concentrate and gold-containing electronic waste. The gold leaching rate of roasted desulfurized gold concentratecan reach 87.56%. For the extraction experiments of three types of gold-containing electronic waste, the gold leaching rate can reach over90% after 2 h. Furthermore, the reagent exhibits good selectivity towards gold. Component analysis indicates that the effective compon-ent in the reagent could be sodium isocyanate.展开更多
There is limited amount of research on surface plasmon resonance(SPR)sensors with self-referencing capabilities which are based on dielectric gratings.In the short-wavelength range,a metal grating sensor is capable of...There is limited amount of research on surface plasmon resonance(SPR)sensors with self-referencing capabilities which are based on dielectric gratings.In the short-wavelength range,a metal grating sensor is capable of simultaneously measuring liquid refractive index under proposed temperature.A fabricated gold grating is placed on one side of a thin gold film for refractive index measurement,while the other with polydimethylsiloxane(PDMS)is deposited on the other side for temperature measurement.We use finite element analysis to research its sensing characteristics.Due to the high refractive index sensitivity of SPR sensors and thermo-optic coefficient of PDMS,we discovered the maximum spectral sensitivity of the sensor is 564 nm/RIU and-50 pm/℃when the liquid refractive index ranges from 1.30 to 1.40 with temperature ranging from 0℃ to 100℃.Numerical results indicate that there may not be mutual interference between two channels for measuring refractive index and temperature,which reduces the complexity of sensor measurements.展开更多
Gold-catalyzed amination reactions based on azides viaα-imino gold carbene intermediates have attracted extensive attention in the past decades because this methodology leads to the facile and efficient construction ...Gold-catalyzed amination reactions based on azides viaα-imino gold carbene intermediates have attracted extensive attention in the past decades because this methodology leads to the facile and efficient construction of synthetically useful N-containing molecules,especially valuable N-heterocycles.However,successful examples of intermolecular generation ofα-imino gold carbenes by using azides as amination reagents are rarely explored probably due to the weak nucleophilicity of azides.Herein,we disclose an efficient gold-catalyzed intermolecular aminative cyclopropanation of ynamides with the allyl azides,enabling flexible synthesis of a wide range of valuable 3-azabicyclo[3.1.0]hex-2-ene derivatives in good to excellent yields with excellent diastereoselectivities.Importantly,this protocol represents the first use of allyl azide as an efficient amination reagent in gold-catalyzed alkyne amination reactions.展开更多
Purpose:The aim was to synthesize quantitative and qualitative research that identified the most effective educational strategies for nurse-led inhaler technique(IT)education in Chronic Obstructive Pulmonary Disease(C...Purpose:The aim was to synthesize quantitative and qualitative research that identified the most effective educational strategies for nurse-led inhaler technique(IT)education in Chronic Obstructive Pulmonary Disease(COPD)patients,as perceived by patients,healthcare providers,and nurses.Methods:A systematic literature search in Embase,PubMed,Cochrane Library,Web of Science,and CINAHL from 2018 to 30 June 2024 was conducted.In total,327 articles were identified.The results of 14 studies that met the inclusion criteria were synthesized.Data were analyzed with des-criptive and semi-quantitative methods to yield summarizing findings on the effectiveness of different educational strate-gies.All investigations had assessed patient adherence to IT.Results:Data indicated that nurse-led IT teaching strategies are effective in promoting IT adherence and correctness in COPD patients utilizing the personalized Teach-Back method.However,studies in disease control and comparison of patient IT satisfaction and self-efficacy need further investigation.Conclusion:The results of this study may contribute to the understanding of the most effective educational strategies in nurse-led IT education for COPD patients.The synthesized findings can be used for the development of new educational interventions and assessment instruments for IT adherence.展开更多
The Sakay gold deposit in Vientiane,Laos,is located in the Indochina landmass of the southeastern segment of the Tethys orogenic belt,specifically within the Vientiane-Pakse micro-landmass and the Vientiane-Pakse meta...The Sakay gold deposit in Vientiane,Laos,is located in the Indochina landmass of the southeastern segment of the Tethys orogenic belt,specifically within the Vientiane-Pakse micro-landmass and the Vientiane-Pakse metallogenic belt.This area is regionally significant for the concentration of minerals such as gold,copper,and tin.The host rocks of the deposit are intermediate volcanic lavas and volcanic tuffs,occurring in near-east-west brittle shear structural fractures through hydrothermal filling and metasomatism.The ore exhibits granular texture,subhedral texture,porphyritic texture,and oriented polycrystalline texture,with structural features such as disseminated,vein-like,and cataclastic breccia.The main ore minerals are pyrite,sphalerite,galena,and chalcopyrite,while the gangue minerals are primarily quartz,calcite,and dolomite.Gold is mainly present as included gold or fissure gold within the crystal lattices and microfractures of minerals such as pyrite and sphalerite.Based on mineral assemblages and generation timing,the mineralization can be divided into three stages:arsenopyrite-pyrite-dolomite-quartz(Ⅰ),sphalerite-galena-chalcopyrite-calcite(Ⅱ),and siderite(Ⅲ),with the latter stages often overlaying the former,showing evident cross-cutting and metasomatic phenomena.The surrounding rocks in the mining area are altered,mainly showing silicification,carbonatization,limonitization,sericitization,and chloritization.Preliminary studies suggest that this deposit is a low-temperature hydrothermal gold deposit within a brittle shear zone.展开更多
Due to the limited regeneration capacity of myocardial tissue after infarction,designing tissue engineering scaffolds are in demand.In the present study,electrospun nanofibrous scaffolds were made out of polyurethane,...Due to the limited regeneration capacity of myocardial tissue after infarction,designing tissue engineering scaffolds are in demand.In the present study,electrospun nanofibrous scaffolds were made out of polyurethane,collagen and gold nanoparticles with random and aligned nanofiber morphologies.The nanoparticles were green-synthesized using saffron extract.Nanoparticle characterizations with UV-Vis.spectroscopy and DLS illustrated theoretical and hydrodynamic diameters of around 7 and 13 nm,respectively,having zeta potential of−37 mV.SEM and TEM micrographs showed the morphology and diameters of obtained nanofibers.Also,further characterization were done by ATR-FTIR,XRD and TGA investigations and degradation studies.Contact angle measurements showed hydrophilic nature of the scaffolds(59±0.6°for aligned PU/Col/Au50 nanofibers compared to 120±2.6°for random PU nanofibers).Mechanical testing demonstrated appropriate tensile properties of the scaffolds for cardiac tissue engineering(Young’s modulus:1.53±0.07 MPa for aligned PU/Col/Au50 nanofibers compared to 0.4±0.05 MPa for random PU nanofibers).Finally,alamar blue assay revealed proper survival of the cells of HUVEC cell line on the prepared scaffolds,where the highest percentages were observed for random and aligned PU/Col/Au50 nanofibers.According to the findings,the fabricated PU/Col/AuNPs nanofibrous scaffolds could be considered as potential cardiac patches.展开更多
This study comprises the relationship between organic matter(OM)and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit(Kazakhstan)and Western Mecsek uranium ore deposit(Hungary).T...This study comprises the relationship between organic matter(OM)and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit(Kazakhstan)and Western Mecsek uranium ore deposit(Hungary).The two ore deposits are identified as organicrich sedimentary formations linked to the Variscan gold cycle globally.Characterizing OM is essential because it can act as a carrier for gold,influencing its distribution and behavior within the deposit.Understanding the nature and distribution of OM can provide insights into the processes of gold deposition and help optimize exploration and extraction strategies in mining operations.The primary objective is to characterize OM by identifying its elemental composition,thermal maturity,functional groups,and soluble fractions;and extract gold from OM using a two-step sequential extraction method(hydrogen peroxide and aqua regia)combined with geochemical techniques.Analytical and experimental results from samples of both ore deposits indicate the presence of finely disseminated solid bitumen and reworked vitrinite,originating from thermally matured(RmcRo%—3.76 in Bakyrchik;Ro%—2.25 in W-Mecsek)terrigenous high plants.Both deposits exhibit extremely low extractable bitumen yield and TOC(0.34%in Bakyrchik;0.25 wt%in W-Mecsek),characterized by an aromatic carboxylic acid organic structure and a composition rich in sulfur-containing(1.17%in Bakyrchik;5.81%in W-Mecsek)aromatic hydrocarbons.Gold occurrence and enrichment within OM were confi rmed through the sequential extraction method employing ICP-OES and LA-ICP-MS techniques.The sequentially extracted gold content from OM reached up to 3 ppm in Bakyrchik and up to 3.28 ppm in Western Mecsek,accompanied by Ag(ranging from 0.01 to 0.32 ppm).Higher concentrations of Au(4 ppm)and Ag(27 ppm)were extracted from residue materials,which are likely associated with sulfide minerals.The presence of gold in OM was further validated using LA-ICP-MS.Gold bonding within OM structure,gold is preserved in the form of lattice gold or structurally bonded metal most likely within the aromatic hydrocarbon fractions of the OM in both the W-Mecsek and Bakyrchik deposits.These findings underscore the profound potential of ongoing exploration endeavors,off ering pivotal revelations regarding the extraction and practical application of Au and Ag derived from OM within the geochemical framework of both ore deposits.展开更多
Transformation of glycerol into value-added che micals via electro-oxidation using the green electricity is considered as a sustainable and promising process.Whereas,the synthesis of specific C3 products such as glyce...Transformation of glycerol into value-added che micals via electro-oxidation using the green electricity is considered as a sustainable and promising process.Whereas,the synthesis of specific C3 products such as glyceric acid(GLA)from electro-oxidation of glycerol still suffers from poor catalytic performance.Here,we used a two-step deposition strategy to prepare Au-CeO_(2)/CNT catalyst for highly efficient electrosynthesis of GLA from glycerol oxidation under alkaline conditions.Upon treating 0.5 mol/L glycerol at 1.12 V(vs.RHE)for 12 h in 1.0 mol/L KOH solution,the glycerol conversion and GLA selectivity over Au-CeO_(2)/CNT achieve 99.7%and 50.0%,respectively.The glycerol conversion doubles when an optimal amount of CeO_(2)is introduced to the Au/CNT catalyst,Au-CeO_(2)/CNT provides numerous active sites at ternary junctions of Au-CeO_(2)-CNT,which effectively suppress the adsorption of GLA on the surface of Au nanoparticles and prevent the nanoparticles from serious agglomeration,thereby facilitate the glycerol-to-GLA conversion with considerable cyclability.This study provides valuable insight into the rational design of high-performance catalysts for alcohol electro-oxidation.展开更多
文摘One feature of Golding' s works is to reveal the theme-the evil nature of man,through the characters' mystical experience.This is obvious in Darkness Visible and Lord of the Flies.This paper tries to find out the resource for the writer to use mystical experience through biological approach.
文摘Beyond the stories,Golding spends much effort on an issue called"impotence of language"in his works,especially Lord of the Flies and Darkness Visible.Thus Golding's language view is worthwhile to research.With help of Lacan's theory of signifier and signified,this paper made a primary glance about Golding's language view within the two novels.
基金support from the National Natural Science Foundation of China(No.52204274)the Shandong Provincial Natural Science Foundation,China(No.ZR2021QE122)+1 种基金Shandong Provincial Department of Science and Technology Key Project,China(No.2023TZXD021)Shandong Provincial Department of Science and Technology,China(No.ZTYJY-KY-2033-11).
文摘Gold ores in the Jiaozhou region of China are characterized by their abundant reserves,low grade,fine dissemination,and chal-lenges in upgrading.Froth flotation,with xanthate as the collector,is a commonly employed method for enriching auriferous pyrite from these ores.This study aimed to develop a more efficient flotation process by utilizing cavitation nanobubbles for a low-grade gold ore.Batch flotation tests demonstrated that nanobubbles significantly enhanced the flotation performance of auriferous pyrite,as evidenced by improved concentrate S and Au grades and their recoveries.The mechanisms underlying this enhancement were explored by investigat-ing surface nanobubble(SNB)formation,bulk nanobubble(BNB)attachment to hydrophobic pyrite surfaces,and nanobubble-induced agglomeration using atomic force microscopy(AFM)and focused beam reflectance measurement(FBRM).The results revealed that nan-obubble coverage on the pyrite surface is a critical factor influencing surface hydrophobicity and agglomeration.SNBs exhibited higher coverage on pyrite surfaces with increased surface hydrophobicity,flow rate,and cavitation time.Similarly,BNB attachment on pyrite surfaces was significantly increased with surface hydrophobicity and cavitation time.Enhanced surface hydrophobicity,along with higher flow rates and cavitation times,promoted pyrite particle agglomeration owing to the increased nanobubble coverage,ultimately leading to improved flotation performance.
基金support from the National Key Research and Development Program of China(2021YFB3201400,2021YFB3201401,2020YFC1908602)the National Natural Science Foundation of China(21904001 and 61774159)+1 种基金the Anhui Provincial Natural Science Foundation(2008085QF288)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Anhui Province(2020LCX032).
文摘Metal-organic framework(MOF)nanostructures have emerged as a prominent class of materials in the advancement of electrochemical sensors.The rational design of bimetallic MOF-functionalized microelectrode is of importance for improv-ing the electrochemical performance but still in great challenge.In this work,the bimetallic FeCo-MOF nanostructures were assembled onto a gold disk ultramicroelectrode(Au UME,5.2μm in diameter)via an in-situ electrodeposition method,which enhanced the sensitive detection of epinephrine(EP).The in-situ electrodeposited FeCo-MOF exhibited a character-istic nanoflower-like morphology and was uniformly dispersed on the Au UME.The FeCo-MOF/Au UME demonstrated excellent electrochemical performance on the detection of EP with a high sensitivity of 36.93μA·μmol^(-1)·L·cm^(-2)and a low detection limit of 1.28μmol·L^(-1).It can be attributed to the nonlinear diffusion of EP onto the ultra-micro working substrate,coupled with synergistical catalytic activity of the bimetallic Fe,Co within MOF structure.Furthermore,the FeCo-MOF/Au UME has been successful applied to the analysis of EP in human serum samples,yielding high recovery rates.These results not only contribute to the expansion of the research area of electrochemical sensors,but also provide novel insights and directions into the development of high-performance MOF-based electrochemical sensors.
基金supported by the Young Talent Innovation Team Support Project from Zhengzhou University(No.32213280)the scientific research program of innovation platform in State Tobacco Monopoly Administrationthe State Key Program of National Natural Science Foundation of China(Grant No.32130083).
文摘Dopamine(DA)is a vital neurotransmitter,and accurate detection of its concentration is critical for both clinical diagnos-tics and neuroscience research.Due to its electrochemical activity,DA is commonly detected using electrochemical methods,which are favored for their simplicity,fast response time,and suitability for in vivo analysis.In this work,a highly sensitive DA electrochemical sensor was developed using an Au@MoS_(2)composite,created by modifying molybdenum disulfide(MoS_(2))nanosheets with gold nanoparticles through HAuCl_(4) reduction,and it was aimed at enhancing DA adsorption and improving detection performance.Scanning Electron Microscopy(SEM),transmission electron microscopy(TEM),Energy Dispersive Spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS)and X-ray Diffraction(XRD)confirmed the suc-cessful synthesis of Au@MoS_(2)and the uniform distribution of gold nanoparticles across the MoS_(2)nanosheets.Then,the electrochemical characterization demonstrated that the Au@MoS_(2)/GCE exhibited distinct oxidation peaks in a 10μmol·L^(-1)DA solution,with significantly enhanced electrochemical activity compared to both unmodified GCE and pristine MoS_(2).Furthermore,differential pulse voltammetry(DPV)further revealed a strong linear relationship between DA concentration and the current response in the range of 800 nmol·L^(-1)to 10μmol·L^(-1),with a low detection limit(LOD)of 78.9 nmol·L^(-1)(S/N=3).Additionally,the sensor showed excellent selectivity against other interfering substances.Moreover,the laser-induced Au@MoS_(2)(LIAu@MoS_(2)),with its abundance of negatively charged surface defects,enabled the ultra-sensitive detection of the ultra-low concentrations of DA.In conclusion,the successfully fabricated Au@MoS_(2)based sensor offers advantages such as low cost,ease of operation,and scalability,making it a promising candidate for biosensing applications due to its enhanced DA detection capabilities.
文摘A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.
基金the National Science Foundation of China (Grant No. NSFC: 92162213)the Geology Department Faculty of Science of Al-Azhar University (Assiut Branch)+2 种基金the China Scholarship CouncilChang'an UniversityIstanbul Technical University's Scientific Research Project (BAP Project ID: 45396, code: FHD-2024-45396)
文摘In the Fatira(Abu Zawal)mine area,located in the northern Eastern Desert of Egypt,fieldwork and mineralogical analysis,integrated with machine learning techniques applied to Landsat-8 OLI,ASTER,and Sentinel-2 multi-spectral imagery(MSI)data delineate gold-sulfide mineralization in altered rocks.Gold(Au)anomalies in hydrothermal breccias and quartz veins are associated with NE-oriented felsite dykes and silicified granitic rocks.Two main alteration types are identified:a pyrite-sericite-quartz and a sulfide-chlorite-carbonate assemblage,locally with dispersed free-milling Au specks.Dimensionality reduction techniques,including principal component analysis(PCA)and independent component analysis(ICA),enabled mapping of alteration types.Sentinel-2 PC125 composite images offered efficient lithological differentiation,while supervised classifications,i.e.,the support vector machine(SVM)of Landsat-8 yielded an accuracy of 88.55%and a Kappa value of 0.86.ASTER mineral indices contributed to map hydrothermal alteration mineral phases,including sericite,muscovite,kaolinite,and iron oxides.Results indicate that post-magmatic epigenetic hydrothermal activity significantly contributed to the Au-sulfide mineralization in the Fatira area,distinguishing it from the more prevalent orogenic gold deposits in the region.
基金financially supported from the National Natural Science Foundation of China(No.52274358)the Natural Science Foundation of Hunan Province,China(No.2020JJ4718)+2 种基金the Major Science and Technology Projects of Gansu Province,China(No.22ZD6GC017)the Young Scientists Fund of National Natural Science Foundation of China(No.51404296)the National Key Research and Development Program of China(No.2018YFC1901604).
文摘Based on the properties of antimony(Sb)and arsenic(As),a method was proposed to enhance gold recovery during iron matte smelting.The impact of Sb and As on gold enhancement capture was investigated using an exclusion method.The results demonstrated that both Sb and As significantly improved the gold recovery rate.As the Sb or As content increased,the gold recovery rate increased.The enhancement effect of Sb was better than that of As,and the optimal results were achieved through the synergistic effects of Sb and As.Under optimized conditions,the gold recovery rate reached 97.12%,whereas the gold content in the slag decreased to 1.70 g/t.Sb captured and aggregated free gold as an Au-Sb alloy,whereas As-Fe alloy also captured free gold.The growth of the gold-captured phase size enhanced the settling velocity,thereby promoting gold recovery.
基金supported by the National Natural Science Foundation of China(42273063)the Young Elite Scientists Sponsorship(YESS)Program of the China Association for Science and Technology(YESS20220661)+1 种基金Fundamental Research Funds for Central Universities(FRF-IDRY-23-004)the Natural Science Foundation of Shandong Province,China(ZR2022QD050).
文摘The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold deposit have been the subject of extensive discussion and analyzed by numerous scholars,a definitive conclusion remains elusive.The Jiuqu Au deposit is a significant metallogenic area in the eastern part of the Linglong gold ore field,characterized as a quartz vein-type gold deposit.Gold mineralization in the Jiuqu gold deposit is classified into four stages,primarily occurring within the Late Jurassic Linglong granite and Early Cretaceous Guojialing granodiorite.Pyrite,the primary gold-bearing mineral at the Jiuqu Gold Mine,has been present throughout the metallogenic period,is rich in a variety of trace elements and is closely related to the formation of gold ore.This study focused on evaluating pyrite from the essential metallogenic stages(Stages Ⅰ-Ⅲ)of the Jiuqu gold deposit using scanning electron microscopy(SEM),electron microprobe analysis(EMPA),laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS) sulfur isotope analysis and detection.The work aimed to reconstruct the origin of metallogenic materials and the evolution of ore-forming fluids and to restrict the genesis of the deposit.Pyrite exhibits discernible alterations in both shape and crystal structure as it progresses through its ore-forming stages.The aforementioned stages can be delineated as follows:type 1 pyrite(PyⅠ),developed in the initial ore stage,is characterized by coarse-to-medium-grained euhedral pyrite in Stage Ⅰ;type 2 pyrite(PyⅡ),developed in the second ore stage,appears during the middle stage of mineralization and is characterized by subhedral or anhedral pyrite;type 3 pyrite(PyⅢ),developed in the third ore stage,primarily occurred in the late-middle stages of mineralization.It is fragmented and coexists with various metal sulfides,including chalcopyrite,sphalerite and galena.The in situ major and elemental compositions of pyrites at Jiuqu indicate that Au,in the form of visible gold,exists in pyrites with low Au and Ag contents throughout all stages.PyⅠ had lower Pb,Bi,Co and Ni contents than those of PyⅡ.PyⅢ displayed decreased Pb,Bi,Co and Ni levels compared with PyⅡ.The δ34S values of the PyⅠ,PyⅡ and PyⅢ pyrite stages ranged from 7.19% to 8.71%,6.24% to 7.68% and 7.66% to 8.07%,respectively.According to the structural and geochemical analysis of pyrite,the ore-forming fluid of the Jiuqu gold deposit was derived from a magmatic-hydrothermal formation created by enriched lithospheric mantle-derived magma,mixing S from Precambrian metamorphic rocks.Previous studies on the H-O isotopes of quartz in the region's ores have indicated the presence of primary magma water.Additionally,studies concerning the C-O isotopes of carbonate minerals in ores have suggested that C may have originated from the mantle.Fluid migration and water-rock interaction resulted in sulfide and gold precipitation.In the Late Meosozoic,lithospheric thinning of eastern North China Craton led to up welling of astheno spheric mantle and partial melting of lithospheric mantle in the Jiaodong area.Under tectonic changes,magmatic-hydro thermal fluid migrated upward along fault structures to form a gold province.
基金financially supported by the National Natural Science Foundation of China (No.51974016)。
文摘Cyanide is the most widely used reagent in gold production processes. However, cyanide is highly toxic and poses safety haz-ards during transportation and use. Therefore, it is necessary to develop gold leaching reagents that can replace cyanide. This paper intro-duces a method for synthesizing a gold leaching reagent. Sodium cyanate is used as the main raw material, with sodium hydroxide and so-dium ferrocyanide used as additives. The gold leaching reagent can be obtained under the conditions of a mass ratio of sodium cyanate,sodium hydroxide, and sodium ferrocyanide of 15:3:1, synthesis temperature of 600℃, and synthesis time of 1 h. This reagent has a goodrecovery effect on gold concentrate and gold-containing electronic waste. The gold leaching rate of roasted desulfurized gold concentratecan reach 87.56%. For the extraction experiments of three types of gold-containing electronic waste, the gold leaching rate can reach over90% after 2 h. Furthermore, the reagent exhibits good selectivity towards gold. Component analysis indicates that the effective compon-ent in the reagent could be sodium isocyanate.
基金supported by the National Natural Science Foundation of China(No.52276094)the Education Project of Hunan Provincial Department(Nos.20B602 and 22C0112)+2 种基金the Industry University Education Cooperation Project(No.230803117185211)the Research Project on Teaching Reform in Ordinary Undergraduate Universities in Hunan Province(No.202401000142)the Natural Science Foundation of Hunan Province(No.2020JJ4935)。
文摘There is limited amount of research on surface plasmon resonance(SPR)sensors with self-referencing capabilities which are based on dielectric gratings.In the short-wavelength range,a metal grating sensor is capable of simultaneously measuring liquid refractive index under proposed temperature.A fabricated gold grating is placed on one side of a thin gold film for refractive index measurement,while the other with polydimethylsiloxane(PDMS)is deposited on the other side for temperature measurement.We use finite element analysis to research its sensing characteristics.Due to the high refractive index sensitivity of SPR sensors and thermo-optic coefficient of PDMS,we discovered the maximum spectral sensitivity of the sensor is 564 nm/RIU and-50 pm/℃when the liquid refractive index ranges from 1.30 to 1.40 with temperature ranging from 0℃ to 100℃.Numerical results indicate that there may not be mutual interference between two channels for measuring refractive index and temperature,which reduces the complexity of sensor measurements.
基金financial support from the National Natural Science Foundation of China(Nos.22125108,22331004 and 22121001)Yunnan Normal University,Applied Basic Research Projects of Yunnan Province(No.202101AT070217)+1 种基金the Jiangxi Provincial Natural Science Foundation(No.20224BAB213013)the Jiangxi Provincial Department of Education in Science and Technology Program Project(No.GJJ210906)。
文摘Gold-catalyzed amination reactions based on azides viaα-imino gold carbene intermediates have attracted extensive attention in the past decades because this methodology leads to the facile and efficient construction of synthetically useful N-containing molecules,especially valuable N-heterocycles.However,successful examples of intermolecular generation ofα-imino gold carbenes by using azides as amination reagents are rarely explored probably due to the weak nucleophilicity of azides.Herein,we disclose an efficient gold-catalyzed intermolecular aminative cyclopropanation of ynamides with the allyl azides,enabling flexible synthesis of a wide range of valuable 3-azabicyclo[3.1.0]hex-2-ene derivatives in good to excellent yields with excellent diastereoselectivities.Importantly,this protocol represents the first use of allyl azide as an efficient amination reagent in gold-catalyzed alkyne amination reactions.
文摘Purpose:The aim was to synthesize quantitative and qualitative research that identified the most effective educational strategies for nurse-led inhaler technique(IT)education in Chronic Obstructive Pulmonary Disease(COPD)patients,as perceived by patients,healthcare providers,and nurses.Methods:A systematic literature search in Embase,PubMed,Cochrane Library,Web of Science,and CINAHL from 2018 to 30 June 2024 was conducted.In total,327 articles were identified.The results of 14 studies that met the inclusion criteria were synthesized.Data were analyzed with des-criptive and semi-quantitative methods to yield summarizing findings on the effectiveness of different educational strate-gies.All investigations had assessed patient adherence to IT.Results:Data indicated that nurse-led IT teaching strategies are effective in promoting IT adherence and correctness in COPD patients utilizing the personalized Teach-Back method.However,studies in disease control and comparison of patient IT satisfaction and self-efficacy need further investigation.Conclusion:The results of this study may contribute to the understanding of the most effective educational strategies in nurse-led IT education for COPD patients.The synthesized findings can be used for the development of new educational interventions and assessment instruments for IT adherence.
文摘The Sakay gold deposit in Vientiane,Laos,is located in the Indochina landmass of the southeastern segment of the Tethys orogenic belt,specifically within the Vientiane-Pakse micro-landmass and the Vientiane-Pakse metallogenic belt.This area is regionally significant for the concentration of minerals such as gold,copper,and tin.The host rocks of the deposit are intermediate volcanic lavas and volcanic tuffs,occurring in near-east-west brittle shear structural fractures through hydrothermal filling and metasomatism.The ore exhibits granular texture,subhedral texture,porphyritic texture,and oriented polycrystalline texture,with structural features such as disseminated,vein-like,and cataclastic breccia.The main ore minerals are pyrite,sphalerite,galena,and chalcopyrite,while the gangue minerals are primarily quartz,calcite,and dolomite.Gold is mainly present as included gold or fissure gold within the crystal lattices and microfractures of minerals such as pyrite and sphalerite.Based on mineral assemblages and generation timing,the mineralization can be divided into three stages:arsenopyrite-pyrite-dolomite-quartz(Ⅰ),sphalerite-galena-chalcopyrite-calcite(Ⅱ),and siderite(Ⅲ),with the latter stages often overlaying the former,showing evident cross-cutting and metasomatic phenomena.The surrounding rocks in the mining area are altered,mainly showing silicification,carbonatization,limonitization,sericitization,and chloritization.Preliminary studies suggest that this deposit is a low-temperature hydrothermal gold deposit within a brittle shear zone.
基金supported by Shiraz University of Medical Sciences,Shiraz,Iran(grant No.:17780).
文摘Due to the limited regeneration capacity of myocardial tissue after infarction,designing tissue engineering scaffolds are in demand.In the present study,electrospun nanofibrous scaffolds were made out of polyurethane,collagen and gold nanoparticles with random and aligned nanofiber morphologies.The nanoparticles were green-synthesized using saffron extract.Nanoparticle characterizations with UV-Vis.spectroscopy and DLS illustrated theoretical and hydrodynamic diameters of around 7 and 13 nm,respectively,having zeta potential of−37 mV.SEM and TEM micrographs showed the morphology and diameters of obtained nanofibers.Also,further characterization were done by ATR-FTIR,XRD and TGA investigations and degradation studies.Contact angle measurements showed hydrophilic nature of the scaffolds(59±0.6°for aligned PU/Col/Au50 nanofibers compared to 120±2.6°for random PU nanofibers).Mechanical testing demonstrated appropriate tensile properties of the scaffolds for cardiac tissue engineering(Young’s modulus:1.53±0.07 MPa for aligned PU/Col/Au50 nanofibers compared to 0.4±0.05 MPa for random PU nanofibers).Finally,alamar blue assay revealed proper survival of the cells of HUVEC cell line on the prepared scaffolds,where the highest percentages were observed for random and aligned PU/Col/Au50 nanofibers.According to the findings,the fabricated PU/Col/AuNPs nanofibrous scaffolds could be considered as potential cardiac patches.
基金Social Policy Grant(064.01.00 SPG)financed by Nazarbayev University,Kazakhstan。
文摘This study comprises the relationship between organic matter(OM)and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit(Kazakhstan)and Western Mecsek uranium ore deposit(Hungary).The two ore deposits are identified as organicrich sedimentary formations linked to the Variscan gold cycle globally.Characterizing OM is essential because it can act as a carrier for gold,influencing its distribution and behavior within the deposit.Understanding the nature and distribution of OM can provide insights into the processes of gold deposition and help optimize exploration and extraction strategies in mining operations.The primary objective is to characterize OM by identifying its elemental composition,thermal maturity,functional groups,and soluble fractions;and extract gold from OM using a two-step sequential extraction method(hydrogen peroxide and aqua regia)combined with geochemical techniques.Analytical and experimental results from samples of both ore deposits indicate the presence of finely disseminated solid bitumen and reworked vitrinite,originating from thermally matured(RmcRo%—3.76 in Bakyrchik;Ro%—2.25 in W-Mecsek)terrigenous high plants.Both deposits exhibit extremely low extractable bitumen yield and TOC(0.34%in Bakyrchik;0.25 wt%in W-Mecsek),characterized by an aromatic carboxylic acid organic structure and a composition rich in sulfur-containing(1.17%in Bakyrchik;5.81%in W-Mecsek)aromatic hydrocarbons.Gold occurrence and enrichment within OM were confi rmed through the sequential extraction method employing ICP-OES and LA-ICP-MS techniques.The sequentially extracted gold content from OM reached up to 3 ppm in Bakyrchik and up to 3.28 ppm in Western Mecsek,accompanied by Ag(ranging from 0.01 to 0.32 ppm).Higher concentrations of Au(4 ppm)and Ag(27 ppm)were extracted from residue materials,which are likely associated with sulfide minerals.The presence of gold in OM was further validated using LA-ICP-MS.Gold bonding within OM structure,gold is preserved in the form of lattice gold or structurally bonded metal most likely within the aromatic hydrocarbon fractions of the OM in both the W-Mecsek and Bakyrchik deposits.These findings underscore the profound potential of ongoing exploration endeavors,off ering pivotal revelations regarding the extraction and practical application of Au and Ag derived from OM within the geochemical framework of both ore deposits.
基金Project supported by the National Natural Science Foundation of China(22161033,21875125)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2023ZD11)+1 种基金the 111 Project(D20033)the"Grassland Talent"Program and"Grassland Talent"Innovation Team of Inner Mongolia。
文摘Transformation of glycerol into value-added che micals via electro-oxidation using the green electricity is considered as a sustainable and promising process.Whereas,the synthesis of specific C3 products such as glyceric acid(GLA)from electro-oxidation of glycerol still suffers from poor catalytic performance.Here,we used a two-step deposition strategy to prepare Au-CeO_(2)/CNT catalyst for highly efficient electrosynthesis of GLA from glycerol oxidation under alkaline conditions.Upon treating 0.5 mol/L glycerol at 1.12 V(vs.RHE)for 12 h in 1.0 mol/L KOH solution,the glycerol conversion and GLA selectivity over Au-CeO_(2)/CNT achieve 99.7%and 50.0%,respectively.The glycerol conversion doubles when an optimal amount of CeO_(2)is introduced to the Au/CNT catalyst,Au-CeO_(2)/CNT provides numerous active sites at ternary junctions of Au-CeO_(2)-CNT,which effectively suppress the adsorption of GLA on the surface of Au nanoparticles and prevent the nanoparticles from serious agglomeration,thereby facilitate the glycerol-to-GLA conversion with considerable cyclability.This study provides valuable insight into the rational design of high-performance catalysts for alcohol electro-oxidation.
