This study deals with the comparative investigation on various classification/characterization systems for sedimentary rocks in two parts,40 kmlong of the Zagros tunnel,west of Iran.The results of extensive geotechnic...This study deals with the comparative investigation on various classification/characterization systems for sedimentary rocks in two parts,40 kmlong of the Zagros tunnel,west of Iran.The results of extensive geotechnical explorations and field measurements were applied to obtain the rock mass classification/characterization systems such as Rock Mass Rating(RMR),Rock Condition Rating(RCR),Q-system(Q),Rock Mass Number(QN),Rock Mass index(RMi),Rock Structure Rating(RSR),and Geological Strength Index(GSI)for a wide range of sedimentary rocks.A set of systems inter-relationship is proposed.Some of these correlation relations such as RMR-Q,RMR-RMi,RMi-Q,RCR,GSI-GSI(Cai)are similar to the one or more relations proposed in the previous studies,however,some of them such as RSR-RMR,RSR-Q,RCR-QN and GSI-RMR are not similar to the previous works.Joint set orientation and joint set number are more important parameters that cause weak correlation coefficients where both side classifications are not similar in considering them in calculating values.So it is proposed to find relations between any pairs of systems that both of them consider or not consider these parameters.The relations are proposed for a wide range of sedimentary rocks and can be applied for similar geological environments.展开更多
Mountain excavation and city construction(MECC)projects being launched in the Loess Plateau in China involve the creation of large-scale artificial land.Understanding the subsurface evolution characteristics of the ar...Mountain excavation and city construction(MECC)projects being launched in the Loess Plateau in China involve the creation of large-scale artificial land.Understanding the subsurface evolution characteristics of the artificial land is essential,yet challenging.Here,we use an improved fiber-optic monitoring system for its subsurface multi-physical characterization.The system enables us to gather spatiotemporal distribution of various parameters,including strata deformation,temperature,and moisture.Yan’an New District was selected as a case study to conduct refined in-situ monitoring through a 77 m-deep borehole and a 30 m-long trench.Findings reveal that the ground settlement involves both the deformation of the filling loess and the underlying intact loess.Notably,the filling loess exhibits a stronger creep capability compared to underlying intact loess.The deformation along the profile is unevenly distributed,with a positive correlation with soil moisture.Water accumulation has been observed at the interface between the filling loess and the underlying intact loess,leading to a significant deformation.Moreover,the temperature and moisture in the filling loess have reached a new equilibrium state,with their depths influenced by atmospheric conditions measuring at 31 m and 26 m,respectively.The refined investigation allows us to identify critical layers that matter the sustainable development of newly created urban areas,and provide improved insights into the evolution mechanisms of land creation.展开更多
Since its discovery in 2010, the NEAG 2 has been one of the most productive oil fields of the Badr El-Din Petroleum Company(BAPETCO) in the northern Western Desert of Egypt. The Albian-Cenomanian reservoir system has ...Since its discovery in 2010, the NEAG 2 has been one of the most productive oil fields of the Badr El-Din Petroleum Company(BAPETCO) in the northern Western Desert of Egypt. The Albian-Cenomanian reservoir system has a unique performance but suffers from several issues hindering its production.The latest production report in 2023, NEAG-2 Field was producing 1760 bbls of oil with 36500 bbls of water, i.e., 95% water cut. Despite that, the field has reached a 39% recovery factor but the reservoir forecast suggests a much higher recovery factor. Therefore, the NEAG 2 Field requires a comprehensive geological model to depict its reservoir heterogeneities better. We introduce a solid and integrated workflow to investigate the reservoir characters among different scales of geological heterogeneity and offer solutions to overcome some data gaps. After characterizing the reservoir elements by the structural,stratigraphic, petrographic, and petrophysical analyses, a machine learning-based method was applied to overcome the missing whole rock cores in creating a detailed electro-facies log for all field wells. The Neural-Network algorithm required the facies types to be grouped into definitive reservoir qualities to be applied. The resultant electro-facies log had a very good match with the input logs, which validated the facies grouping. This was followed by the porosity-permeability transforms, estimated from mobility data, to create a permeability curve for all field wells, despite the unavailability of core data. The reservoir was categorized into three rock types, each with a specific range of quality, signifying their different flow abilities which were supported by dynamic data. The Lower Bahariya-Kharita in NEAG 2 was ultimately concluded to be a complex heterogeneous reservoir with varying flow abilities and production behaviors.The recovery factor mismatch is due to unrecovered reserves, and a new production strategy should be introduced to reach the ultimate recovery. This integration of geologic and dynamic data is strongly recommended for any reservoir characterization study to avoid oversimplifying the reservoir system and to design the right reservoir development plan.展开更多
Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the preven...Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the prevention and control of LF.Methods Samples of cerebrospinal fluid(CSF),blood,urine,saliva,and environmental materials were collected from the patient and their close contacts for LASV nucleotide detection.Whole-genome sequencing was performed on positive samples to analyze the genetic characteristics of the virus.Results LASV was detected in the patient’s CSF,blood,and urine,while all samples from close contacts and the environment tested negative.The virus belongs to the lineage IV strain and shares the highest homology with strains from Sierra Leone.The variability in the glycoprotein complex(GPC)among different strains ranged from 3.9%to 15.1%,higher than previously reported for the seven known lineages.Amino acid mutation analysis revealed multiple mutations within the GPC immunogenic epitopes,increasing strain diversity and potentially impacting immune response.Conclusion The case was confirmed through nucleotide detection,with no evidence of secondary transmission or viral spread.The LASV strain identified belongs to lineage IV,with broader GPC variability than previously reported.Mutations in the immune-related sites of GPC may affect immune responses,necessitating heightened vigilance regarding the virus.展开更多
With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,off...With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,offers a promising avenue for researchers.However,the question of how to significantly enhance the performance of catalysts has gradually drawn the attention of scholars.Defect engineering,a commonly employed and effective approach to improve catalyst activity,has become a significant research focus in the catalysis field in recent years.Nonmetal vacancies have received extensive attention due to their simple form.Consequently,exploration of metal vacancies has remained stagnant for a considerable period,resulting in a scarcity of comprehensive reviews on this topic.Therefore,based on the latest research findings,this paper summarizes and consolidates the construction strategies for metal vacancies,characterization techniques,and their roles in typical energy and environmental catalytic reactions.Additionally,it outlines potential challenges in the future,aiming to provide valuable references for researchers interested in investigating metal vacancies.展开更多
A Oilfield is the most representative mid to deep oil field in the Bohai Sea, with the main oil bearing intervals being the upper and middle Shahejie-3 sections of the Paleogene Shahejie Formation. By combining well s...A Oilfield is the most representative mid to deep oil field in the Bohai Sea, with the main oil bearing intervals being the upper and middle Shahejie-3 sections of the Paleogene Shahejie Formation. By combining well seismic analysis, the middle section of Shahejie-3 is divided into high-level system tract and forced lake retreat system tract, corresponding to the II oil formation and I oil formation, respectively. Using sequence stratigraphy methods, based on seismic profiles and drilling lithological cycles, the high stand system tract is divided into 5 stages of delta progradation. The first and second stages are high angle S-type progradation with large sedimentary thickness, the third stage is oblique progradation, and the fourth and fifth stages are S-oblique composite progradation;By combining seismic data, we characterized the large-scale (8 small-scale) progradation bodies of 5 periods, clarified the distribution characteristics of reservoir planes, and laid the foundation for the later exploration of oilfield potential.展开更多
BACKGROUND Artificial intelligence(AI)has potential in the optical diagnosis of colorectal polyps.AIM To evaluate the feasibility of the real-time use of the computer-aided diagnosis system(CADx)AI for ColoRectal Poly...BACKGROUND Artificial intelligence(AI)has potential in the optical diagnosis of colorectal polyps.AIM To evaluate the feasibility of the real-time use of the computer-aided diagnosis system(CADx)AI for ColoRectal Polyps(AI4CRP)for the optical diagnosis of diminutive colorectal polyps and to compare the performance with CAD EYE^(TM)(Fujifilm,Tokyo,Japan).CADx influence on the optical diagnosis of an expert endoscopist was also investigated.METHODS AI4CRP was developed in-house and CAD EYE was proprietary software provided by Fujifilm.Both CADxsystems exploit convolutional neural networks.Colorectal polyps were characterized as benign or premalignant and histopathology was used as gold standard.AI4CRP provided an objective assessment of its characterization by presenting a calibrated confidence characterization value(range 0.0-1.0).A predefined cut-off value of 0.6 was set with values<0.6 indicating benign and values≥0.6 indicating premalignant colorectal polyps.Low confidence characterizations were defined as values 40%around the cut-off value of 0.6(<0.36 and>0.76).Self-critical AI4CRP’s diagnostic performances excluded low confidence characterizations.RESULTS AI4CRP use was feasible and performed on 30 patients with 51 colorectal polyps.Self-critical AI4CRP,excluding 14 low confidence characterizations[27.5%(14/51)],had a diagnostic accuracy of 89.2%,sensitivity of 89.7%,and specificity of 87.5%,which was higher compared to AI4CRP.CAD EYE had a 83.7%diagnostic accuracy,74.2%sensitivity,and 100.0%specificity.Diagnostic performances of the endoscopist alone(before AI)increased nonsignificantly after reviewing the CADx characterizations of both AI4CRP and CAD EYE(AI-assisted endoscopist).Diagnostic performances of the AI-assisted endoscopist were higher compared to both CADx-systems,except for specificity for which CAD EYE performed best.CONCLUSION Real-time use of AI4CRP was feasible.Objective confidence values provided by a CADx is novel and self-critical AI4CRP showed higher diagnostic performances compared to AI4CRP.展开更多
2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(...2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(4)H_(2)N)C_(6)H4NC(Ph)=NDipp]-,Dipp=2,6-iPr_(2)C_(6)H_(3))were investigated.The 1H NMR spectroscopy indicate that the reaction of ytrrium dialkyl complex with one equivalent of 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10) produce the mixture of ytrrium alkyl-amido complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))(CH_(2)SiMe3)](R=CH_(3),2a;R=Ph,2b)and bis(amido)complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))_(2)](R=CH_(3),3a;R=Ph,3b).The yttrium bridging imido complex[Y(L)(2-CH_(3)-1-N-o-C_(2)B_(10)H_(10))]_(2)(4a)was obtained by heating the mixture at 55℃for 12 h.Complex 3a was isolated and characterized by treating the yttrium dialkyl complex with two equivalents of 1a.The structures of complexes 3a and 4a were verified by single-crystal Xray diffraction.CCDC:2424136,3a;2424137,4a.展开更多
A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]py...A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]pyrazine scaffold was serendipitously prepared from the reaction of the pro-ligand of H_(2)L1(N,N'-bis(pyrazin-2-ylmethyl)pyrazine-2,3-dicarboxamide) with CuSO_(4)·5H_(2O) in aqueous solution at room temperature.Complex 1 was characterized by IR,single-crystal X-ray analysis,and magnetic susceptibility measurements.Single-crystal X-ray analysis reveals that the complex consists of three Cu(Ⅱ) ions,two in situ transformed L2~-ligands,two coordinated sulfates,seven coordinated water molecules,and eight uncoordinated water molecules.Magnetic susceptibility measurement indicates that there are obvious ferromagnetic coupling interactions between the adjacent Cu(Ⅱ) ions in 1.CCDC:1852713.展开更多
The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monit...The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.展开更多
On a compact Riemann surface with finite punctures P_(1),…P_(k),we define toric curves as multivalued,totallyunramified holomorphic maps to P^(n)with monodromy in a maximal torus of PSU(n+1).Toric solutions to SU(n+1...On a compact Riemann surface with finite punctures P_(1),…P_(k),we define toric curves as multivalued,totallyunramified holomorphic maps to P^(n)with monodromy in a maximal torus of PSU(n+1).Toric solutions to SU(n+1)Todasystems on X\{P_(1);…;P_(k)}are recognized by the associated toric curves in.We introduce character n-ensembles as-tuples of meromorphic one-forms with simple poles and purely imaginary periods,generating toric curves on minus finitelymany points.On X,we establish a correspondence between character-ensembles and toric solutions to the SU(n+1)system with finitely many cone singularities.Our approach not only broadens seminal solutions with two conesingularities on the Riemann sphere,as classified by Jost-Wang(Int.Math.Res.Not.,2002,(6):277-290)andLin-Wei-Ye(Invent.Math.,2012,190(1):169-207),but also advances beyond the limits of Lin-Yang-Zhong’s existencetheorems(J.Differential Geom.,2020,114(2):337-391)by introducing a new solution class.展开更多
High-pressure research has emerged as a pivotal approach for advancing our understanding and development of optoelectronic materials,which are vital for a wide range of applications,including photovoltaics,light-emitt...High-pressure research has emerged as a pivotal approach for advancing our understanding and development of optoelectronic materials,which are vital for a wide range of applications,including photovoltaics,light-emitting devices,and photodetectors.This review highlights various in situ characterization methods employed in high-pressure research to investigate the optical,electronic,and structural properties of optoelectronic materials.We explore the advances that have been made in techniques such as X-ray diffraction,absorption spectroscopy,nonlinear optics,photoluminescence spectroscopy,Raman spectroscopy,and photoresponse measurement,emphasizing how these methods have enhanced the elucidation of structural transitions,bandgap modulation,performance optimization,and carrier dynamics engineering.These insights underscore the pivotal role of high-pressure techniques in optimizing and tailoring optoelectronic materials for future applications.展开更多
The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based t...The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based techniques with Self-Organizing Maps.展开更多
Aeromonas spp.are commonly found in spoilage of chilled meat.Aeromonas salmonicida NCM 29 and A.salmonicida NCM 57 have been discovered the spoilage heterogeneity in degrading myofibrillar protein.In this study,the tw...Aeromonas spp.are commonly found in spoilage of chilled meat.Aeromonas salmonicida NCM 29 and A.salmonicida NCM 57 have been discovered the spoilage heterogeneity in degrading myofibrillar protein.In this study,the two strains were tested to uncover the discrepancy of meat spoilage in collagen-rich chilled meat and extracted collagen.The results revealed that chicken claws,riched in collagen,inoculated with NCM 29 showed higher values of total viable counts(TVC),total volatile basic nitrogen(TVB-N),pH,adhered cells,trichloroacetic acid(TCA)-soluble peptides,and protease activity compared to those inoculated with NCM 57.Furthermore,NCM 29 generated higher quantity of volatile organic compounds related to meat spoilage.The collagenase((hemagglutinin protease(Hap))secreted by NCM 29 has been identified as the key factor responsible for the observed discrepancies in spoilage,which gradually degraded collagen into peptides and hydroxyproline.The capacity of Hap to degrade type Ⅰ collagen in vitro indicated that it has apparent proteolytic activity,which could reduce the average particle size and alter secondary structure of collagen.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)further confirmed the degradation of theβ-chain in collagen.These findings not only provide a theoretical basis for in-depth investigation of the meat spoilage mechanisms of Aeromonas spp.,but also encourage us to take measures to avoid the spoilage of related bacteria such as Aeromonas spp.during the preservation process.展开更多
This review article provides a comprehensive examination of the most recent advances in research on nanoglasses,including the methods used to create these materials,their characteristics,and their diverse range of use...This review article provides a comprehensive examination of the most recent advances in research on nanoglasses,including the methods used to create these materials,their characteristics,and their diverse range of uses.An overview of the current trends in nanoglass research connects them to the Sustainable Development Goals,highlighting the current relevance of this topic.The process of manufacturing nanoglasses is explained in depth,highlighting advanced approaches such as inert gas condensation and severe plastic deformation,among other techniques.The prime focus of this review is on analyzing the various dimensions of nanoglass materials,including their structural dynamics and electrical configurations,and how these features contribute to their exceptional thermal stability and mechanical strength.The magnetic characteristics of nanoglasses are examined,highlighting their potential for driving innovation across multiple industries.The primary emphasis is on the biological usefulness of nanoglasses,specifically examining their bioactivity and interaction with biological components,and emphasizing their growing use in nanoscale biomedical applications.With regard to the practical applications of nanoglasses,there are specific discussions of their contributions to biological evaluation,wound healing,catalysis,and environmental sustainability.There is an emphasis on the durability and resistance of nanoglasses in these contexts.The comprehensive overview of nanoglasses provided in this article highlights their significance as revolutionary materials in fields of science and technology.The potential of nanoglasses to contribute to a future that is more sustainable and health oriented is indicated.The article ends by discussing the future directions for nanoglass research and looks forward to the promising possibilities for further investigation and innovation.展开更多
The advancement of electron microscopy technology has driven the development of electron microscopes that can apply mechanical loading while observing samples,providing a valuable tool for In-Situ mechanical character...The advancement of electron microscopy technology has driven the development of electron microscopes that can apply mechanical loading while observing samples,providing a valuable tool for In-Situ mechanical characterization of materials.In response to the need to characterize the evolution of the mechanical behavior of structural materials,such as aerospace materials,in real cryogenic service environments,and to provide an experimental basis for improving their macroscopic cryogenic mechanical properties,the advancement of In-Situ characterization techniques capable of offering both cryogenic environments and mechanical loading has become imperative.There have been scholars using this technique to carry out cryogenic mechanical In-Situ studies of related materials,with experimental studies dominating in general,and a few reviews of mechanical characterization techniques mentioning cryogenic temperatures.In order to make it easier to conduct research using such characterization techniques and to further promote the development of related characterization techniques,this review compiles the previous work and summarizes the electron microscope-based In-Situ characterization techniques for cryogenic micro-and nanomechanics.These techniques primarily include transmission electron microscopy-based cryogenic tensile and indentation methods,as well as scanning electron microscopy-based cryogenic tensile,indentation,compression,and bending methods.Furthermore,the review outlines the prospective future development of In-Situ characterization techniques for cryogenic micro-and nanomechanics.展开更多
Research-based on lignin as a bioproduct has grown due to its high availability,reactivity,physicochemical sta-bility,and abundance of different aromatic units.Lignin consists of various functional groups,which can re...Research-based on lignin as a bioproduct has grown due to its high availability,reactivity,physicochemical sta-bility,and abundance of different aromatic units.Lignin consists of various functional groups,which can react in various chemical reactions and serve as a raw material in various processes to obtain multiple products.These characteristics make lignin suitable for synthesizing products from natural raw materials,replacing fossil ones.Due to a high aromatic variety and complex structural arrangement,lignin isolation and fractionation are still challenging.The aim and novelty of this work was the modification of severity and enzymatic hydrolysis proce-dure on an industrial pre-treatment to improve by-products of birch processing as a raw material for the potential production of different products.Lignin from birch wood enzymatic hydrolysis was obtained and marked accord-ingly:HS(high severity),MS(medium severity),and LS(low severity)lignin.Samples were characterized by ash content,analytical pyrolysis,solubility,and viscosity.HS lignin was characterized by a relatively high carbohy-drate content(16%)and lower lignin content(77%).Meanwhile,LS lignin showed increased lignin content(83%)and reduced carbohydrate content(9%).It can be concluded that the delignification process greatly influ-ences the properties of the obtained lignin.HS lignin resulted in a lower polydispersity index(PDI)and more condensed structure,while LS lignin showed a higher PDI but a lower content of carbohydrates.Therefore,look-ing for a golden middle way is necessary whilefinding the conditions according to the usefield.展开更多
Sea buckthorn(Hippophae rhamnoides L.)is a natural homologous substance of medicine and food.Polysaccharide,as one of its primary active components,has very superior biological activity and can be used as a dietary su...Sea buckthorn(Hippophae rhamnoides L.)is a natural homologous substance of medicine and food.Polysaccharide,as one of its primary active components,has very superior biological activity and can be used as a dietary supplement for functional foods,with good commercial prospects.Although initial progress has been made in the study of sea buckthorn polysaccharides,related studies have been fragmented and lacked systematic and generalization.This manuscript presents a critical analysis and systematic summary of the extraction and purification methods,structural characterization and physicochemical properties,biological activity and potential mechanisms,and structure-activity relationships of sea buckthorn polysaccharides.Accumulating evidence has indicated that sea buckthorn polysaccharides,which were widely prepared by water extraction and column chromatography purifications,exhibited exhibit superior biological activities in vitro and in vivo,including antioxidant,immunomodulatory,anti-inflammatory,hepatorenal protective,antibacterial,antiviral,and prebiotic activities.After analysis,it was concluded that there is a correlation between the relevant activities of sea buckthorn polysaccharides and that the structure of sea buckthorn polysaccharides has a great influence on their biological activity.We reviewed the challenges and limitations of sea buckthorn polysaccharides,summarized the critical aspects,and provided suggestions for potential breakthroughs in the research and application of sea buckthorn polysaccharide.展开更多
High-purity SiO_(2)nanoparticles(SNPs)play a crucial role in various electronic applications,such as semiconductors,solar cells,optical fibers,lenses,and insulating layers,given their purity and particle size,which si...High-purity SiO_(2)nanoparticles(SNPs)play a crucial role in various electronic applications,such as semiconductors,solar cells,optical fibers,lenses,and insulating layers,given their purity and particle size,which significantly impact device efficiency.This study fo-cuses on the synthesis and characterization of pure SNPs through the chemical etching of greater club rush.White powder SNPs were pre-pared using HCl etching,and their thermal behaviors were analyzed via thermogravimetric analysis/differential scanning calorimetry.Structural properties were investigated using X-ray fluorescence,scanning electron microscopy,and transmission electron microscopy.X-ray absorption near-edge structure was employed to assess the oxidation state of the SNPs.The morphology of the SNPs after the first etching was amorphous,with sizes ranging from 50 to 100 nm,which increased to 50-200 nm after the second etching.Despite this size variation,the SNPs maintained a high purity level of 99.8wt%SiO_(2),comparable with industry standards.Notably,the second etching with 0.1-M HCl significantly enhanced the purity level,achieving 99.8wt%SiO_(2)mass.Furthermore,HCl etching facilitated the formation of SiO_(2)in the Si^(4+)oxidation state,akin to industrial SNPs.These findings underscore the critical role of HCl etching in synthesizing high-purity SNPs,with potential applications in advanced electronic devices.展开更多
As a novel two-dimensional(2D)material,MXenes are anticipated to have a significant impact on future aqueous energy storage and conversion technologies owing to their unique intrinsic laminar structure and exceptional...As a novel two-dimensional(2D)material,MXenes are anticipated to have a significant impact on future aqueous energy storage and conversion technologies owing to their unique intrinsic laminar structure and exceptional physicochemical properties.Nevertheless,the fabrication and utilization of functional MXenebased devices face formidable challenges due to their susceptibility to oxidative degradation in aqueous solutions.This review begins with an outline of various preparation techniques for MXenes and their implications for structure and surface chemistry.Subsequently,the controversial oxidation mechanisms are discussed,followed by a summary of currently employed oxidation characterization techniques.Additionally,the factors influencing MXene oxidation are then introduced,encompassing chemical composition(types of M,X elements,layer numbers,terminations,and defects)as well as environment(atmosphere,temperature,light,potential,solution pH,free water and O_(2)content).The review then shifts its focus to strategies aiming to prevent or delay MXene oxidation,thereby expanding the applicability of MXenes in complex environments.Finally,the challenges and prospects within this rapidly-growing research field are presented to promote further advancements of MXenes in aqueous storage systems.展开更多
文摘This study deals with the comparative investigation on various classification/characterization systems for sedimentary rocks in two parts,40 kmlong of the Zagros tunnel,west of Iran.The results of extensive geotechnical explorations and field measurements were applied to obtain the rock mass classification/characterization systems such as Rock Mass Rating(RMR),Rock Condition Rating(RCR),Q-system(Q),Rock Mass Number(QN),Rock Mass index(RMi),Rock Structure Rating(RSR),and Geological Strength Index(GSI)for a wide range of sedimentary rocks.A set of systems inter-relationship is proposed.Some of these correlation relations such as RMR-Q,RMR-RMi,RMi-Q,RCR,GSI-GSI(Cai)are similar to the one or more relations proposed in the previous studies,however,some of them such as RSR-RMR,RSR-Q,RCR-QN and GSI-RMR are not similar to the previous works.Joint set orientation and joint set number are more important parameters that cause weak correlation coefficients where both side classifications are not similar in considering them in calculating values.So it is proposed to find relations between any pairs of systems that both of them consider or not consider these parameters.The relations are proposed for a wide range of sedimentary rocks and can be applied for similar geological environments.
基金supported by National Natural Science Foundation of China(Grant Nos.4203070 and 41977217)the Key Research&Development Program of Shaanxi Province(Grant No.2020ZDLSF06-03).
文摘Mountain excavation and city construction(MECC)projects being launched in the Loess Plateau in China involve the creation of large-scale artificial land.Understanding the subsurface evolution characteristics of the artificial land is essential,yet challenging.Here,we use an improved fiber-optic monitoring system for its subsurface multi-physical characterization.The system enables us to gather spatiotemporal distribution of various parameters,including strata deformation,temperature,and moisture.Yan’an New District was selected as a case study to conduct refined in-situ monitoring through a 77 m-deep borehole and a 30 m-long trench.Findings reveal that the ground settlement involves both the deformation of the filling loess and the underlying intact loess.Notably,the filling loess exhibits a stronger creep capability compared to underlying intact loess.The deformation along the profile is unevenly distributed,with a positive correlation with soil moisture.Water accumulation has been observed at the interface between the filling loess and the underlying intact loess,leading to a significant deformation.Moreover,the temperature and moisture in the filling loess have reached a new equilibrium state,with their depths influenced by atmospheric conditions measuring at 31 m and 26 m,respectively.The refined investigation allows us to identify critical layers that matter the sustainable development of newly created urban areas,and provide improved insights into the evolution mechanisms of land creation.
文摘Since its discovery in 2010, the NEAG 2 has been one of the most productive oil fields of the Badr El-Din Petroleum Company(BAPETCO) in the northern Western Desert of Egypt. The Albian-Cenomanian reservoir system has a unique performance but suffers from several issues hindering its production.The latest production report in 2023, NEAG-2 Field was producing 1760 bbls of oil with 36500 bbls of water, i.e., 95% water cut. Despite that, the field has reached a 39% recovery factor but the reservoir forecast suggests a much higher recovery factor. Therefore, the NEAG 2 Field requires a comprehensive geological model to depict its reservoir heterogeneities better. We introduce a solid and integrated workflow to investigate the reservoir characters among different scales of geological heterogeneity and offer solutions to overcome some data gaps. After characterizing the reservoir elements by the structural,stratigraphic, petrographic, and petrophysical analyses, a machine learning-based method was applied to overcome the missing whole rock cores in creating a detailed electro-facies log for all field wells. The Neural-Network algorithm required the facies types to be grouped into definitive reservoir qualities to be applied. The resultant electro-facies log had a very good match with the input logs, which validated the facies grouping. This was followed by the porosity-permeability transforms, estimated from mobility data, to create a permeability curve for all field wells, despite the unavailability of core data. The reservoir was categorized into three rock types, each with a specific range of quality, signifying their different flow abilities which were supported by dynamic data. The Lower Bahariya-Kharita in NEAG 2 was ultimately concluded to be a complex heterogeneous reservoir with varying flow abilities and production behaviors.The recovery factor mismatch is due to unrecovered reserves, and a new production strategy should be introduced to reach the ultimate recovery. This integration of geologic and dynamic data is strongly recommended for any reservoir characterization study to avoid oversimplifying the reservoir system and to design the right reservoir development plan.
基金supported by Public Health Talent Training and Surport Plan(National Administration of Disease Prevention and Control)Research and application of new technology for rapid monitoring and tracing of emergent infectious diseases among entry-exit population(2024YFFK0056)Monitoring,Early warning and Response of Major Infectious Diseases(2022ZDZX0017).
文摘Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the prevention and control of LF.Methods Samples of cerebrospinal fluid(CSF),blood,urine,saliva,and environmental materials were collected from the patient and their close contacts for LASV nucleotide detection.Whole-genome sequencing was performed on positive samples to analyze the genetic characteristics of the virus.Results LASV was detected in the patient’s CSF,blood,and urine,while all samples from close contacts and the environment tested negative.The virus belongs to the lineage IV strain and shares the highest homology with strains from Sierra Leone.The variability in the glycoprotein complex(GPC)among different strains ranged from 3.9%to 15.1%,higher than previously reported for the seven known lineages.Amino acid mutation analysis revealed multiple mutations within the GPC immunogenic epitopes,increasing strain diversity and potentially impacting immune response.Conclusion The case was confirmed through nucleotide detection,with no evidence of secondary transmission or viral spread.The LASV strain identified belongs to lineage IV,with broader GPC variability than previously reported.Mutations in the immune-related sites of GPC may affect immune responses,necessitating heightened vigilance regarding the virus.
基金financially supported by National Key R&D Program of China(2021YFB3500702)National Natural Science Foundation of China(Nos.21677010 and 51808037)Special fund of Beijing Key Laboratory of Indoor Air Quality Evaluation and Control(No.BZ0344KF21-04).
文摘With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,offers a promising avenue for researchers.However,the question of how to significantly enhance the performance of catalysts has gradually drawn the attention of scholars.Defect engineering,a commonly employed and effective approach to improve catalyst activity,has become a significant research focus in the catalysis field in recent years.Nonmetal vacancies have received extensive attention due to their simple form.Consequently,exploration of metal vacancies has remained stagnant for a considerable period,resulting in a scarcity of comprehensive reviews on this topic.Therefore,based on the latest research findings,this paper summarizes and consolidates the construction strategies for metal vacancies,characterization techniques,and their roles in typical energy and environmental catalytic reactions.Additionally,it outlines potential challenges in the future,aiming to provide valuable references for researchers interested in investigating metal vacancies.
文摘A Oilfield is the most representative mid to deep oil field in the Bohai Sea, with the main oil bearing intervals being the upper and middle Shahejie-3 sections of the Paleogene Shahejie Formation. By combining well seismic analysis, the middle section of Shahejie-3 is divided into high-level system tract and forced lake retreat system tract, corresponding to the II oil formation and I oil formation, respectively. Using sequence stratigraphy methods, based on seismic profiles and drilling lithological cycles, the high stand system tract is divided into 5 stages of delta progradation. The first and second stages are high angle S-type progradation with large sedimentary thickness, the third stage is oblique progradation, and the fourth and fifth stages are S-oblique composite progradation;By combining seismic data, we characterized the large-scale (8 small-scale) progradation bodies of 5 periods, clarified the distribution characteristics of reservoir planes, and laid the foundation for the later exploration of oilfield potential.
文摘BACKGROUND Artificial intelligence(AI)has potential in the optical diagnosis of colorectal polyps.AIM To evaluate the feasibility of the real-time use of the computer-aided diagnosis system(CADx)AI for ColoRectal Polyps(AI4CRP)for the optical diagnosis of diminutive colorectal polyps and to compare the performance with CAD EYE^(TM)(Fujifilm,Tokyo,Japan).CADx influence on the optical diagnosis of an expert endoscopist was also investigated.METHODS AI4CRP was developed in-house and CAD EYE was proprietary software provided by Fujifilm.Both CADxsystems exploit convolutional neural networks.Colorectal polyps were characterized as benign or premalignant and histopathology was used as gold standard.AI4CRP provided an objective assessment of its characterization by presenting a calibrated confidence characterization value(range 0.0-1.0).A predefined cut-off value of 0.6 was set with values<0.6 indicating benign and values≥0.6 indicating premalignant colorectal polyps.Low confidence characterizations were defined as values 40%around the cut-off value of 0.6(<0.36 and>0.76).Self-critical AI4CRP’s diagnostic performances excluded low confidence characterizations.RESULTS AI4CRP use was feasible and performed on 30 patients with 51 colorectal polyps.Self-critical AI4CRP,excluding 14 low confidence characterizations[27.5%(14/51)],had a diagnostic accuracy of 89.2%,sensitivity of 89.7%,and specificity of 87.5%,which was higher compared to AI4CRP.CAD EYE had a 83.7%diagnostic accuracy,74.2%sensitivity,and 100.0%specificity.Diagnostic performances of the endoscopist alone(before AI)increased nonsignificantly after reviewing the CADx characterizations of both AI4CRP and CAD EYE(AI-assisted endoscopist).Diagnostic performances of the AI-assisted endoscopist were higher compared to both CADx-systems,except for specificity for which CAD EYE performed best.CONCLUSION Real-time use of AI4CRP was feasible.Objective confidence values provided by a CADx is novel and self-critical AI4CRP showed higher diagnostic performances compared to AI4CRP.
文摘2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(4)H_(2)N)C_(6)H4NC(Ph)=NDipp]-,Dipp=2,6-iPr_(2)C_(6)H_(3))were investigated.The 1H NMR spectroscopy indicate that the reaction of ytrrium dialkyl complex with one equivalent of 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10) produce the mixture of ytrrium alkyl-amido complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))(CH_(2)SiMe3)](R=CH_(3),2a;R=Ph,2b)and bis(amido)complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))_(2)](R=CH_(3),3a;R=Ph,3b).The yttrium bridging imido complex[Y(L)(2-CH_(3)-1-N-o-C_(2)B_(10)H_(10))]_(2)(4a)was obtained by heating the mixture at 55℃for 12 h.Complex 3a was isolated and characterized by treating the yttrium dialkyl complex with two equivalents of 1a.The structures of complexes 3a and 4a were verified by single-crystal Xray diffraction.CCDC:2424136,3a;2424137,4a.
文摘A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]pyrazine scaffold was serendipitously prepared from the reaction of the pro-ligand of H_(2)L1(N,N'-bis(pyrazin-2-ylmethyl)pyrazine-2,3-dicarboxamide) with CuSO_(4)·5H_(2O) in aqueous solution at room temperature.Complex 1 was characterized by IR,single-crystal X-ray analysis,and magnetic susceptibility measurements.Single-crystal X-ray analysis reveals that the complex consists of three Cu(Ⅱ) ions,two in situ transformed L2~-ligands,two coordinated sulfates,seven coordinated water molecules,and eight uncoordinated water molecules.Magnetic susceptibility measurement indicates that there are obvious ferromagnetic coupling interactions between the adjacent Cu(Ⅱ) ions in 1.CCDC:1852713.
基金湖南省教育厅基金优秀青年项目(No.22B0482)湖南科技大学博士启动基金(No.E51992 and E51993)资助。
文摘The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.
基金supported by the National Natural Science Foundation of China(11931009,12271495,11971450,and 12071449)Anhui Initiative in Quantum Information Technologies(AHY150200)the Project of Stable Support for Youth Team in Basic Research Field,Chinese Academy of Sciences(YSBR-001).
文摘On a compact Riemann surface with finite punctures P_(1),…P_(k),we define toric curves as multivalued,totallyunramified holomorphic maps to P^(n)with monodromy in a maximal torus of PSU(n+1).Toric solutions to SU(n+1)Todasystems on X\{P_(1);…;P_(k)}are recognized by the associated toric curves in.We introduce character n-ensembles as-tuples of meromorphic one-forms with simple poles and purely imaginary periods,generating toric curves on minus finitelymany points.On X,we establish a correspondence between character-ensembles and toric solutions to the SU(n+1)system with finitely many cone singularities.Our approach not only broadens seminal solutions with two conesingularities on the Riemann sphere,as classified by Jost-Wang(Int.Math.Res.Not.,2002,(6):277-290)andLin-Wei-Ye(Invent.Math.,2012,190(1):169-207),but also advances beyond the limits of Lin-Yang-Zhong’s existencetheorems(J.Differential Geom.,2020,114(2):337-391)by introducing a new solution class.
基金supported by the National Nature Science Foundation of China(NSFC)(Grant Nos.22275004,62274040,and 62304046)the Shanghai Science and Technology Committee(Grant No.22JC1410300)+2 种基金the Shanghai Key Laboratory of Novel Extreme Condition Materials(Grant No.22dz2260800)the National Key Research and Development Program of China(Grant No.2022YFE0137400)the Shanghai Science and Technology Innovationaction Plan(Grant No.24DZ3001200).
文摘High-pressure research has emerged as a pivotal approach for advancing our understanding and development of optoelectronic materials,which are vital for a wide range of applications,including photovoltaics,light-emitting devices,and photodetectors.This review highlights various in situ characterization methods employed in high-pressure research to investigate the optical,electronic,and structural properties of optoelectronic materials.We explore the advances that have been made in techniques such as X-ray diffraction,absorption spectroscopy,nonlinear optics,photoluminescence spectroscopy,Raman spectroscopy,and photoresponse measurement,emphasizing how these methods have enhanced the elucidation of structural transitions,bandgap modulation,performance optimization,and carrier dynamics engineering.These insights underscore the pivotal role of high-pressure techniques in optimizing and tailoring optoelectronic materials for future applications.
文摘The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based techniques with Self-Organizing Maps.
基金supported by projects funded by grants from the Natural Science Foundation of Jiangsu Province in China(BK20221515)the National Natural Science Foundation of China(32172266).
文摘Aeromonas spp.are commonly found in spoilage of chilled meat.Aeromonas salmonicida NCM 29 and A.salmonicida NCM 57 have been discovered the spoilage heterogeneity in degrading myofibrillar protein.In this study,the two strains were tested to uncover the discrepancy of meat spoilage in collagen-rich chilled meat and extracted collagen.The results revealed that chicken claws,riched in collagen,inoculated with NCM 29 showed higher values of total viable counts(TVC),total volatile basic nitrogen(TVB-N),pH,adhered cells,trichloroacetic acid(TCA)-soluble peptides,and protease activity compared to those inoculated with NCM 57.Furthermore,NCM 29 generated higher quantity of volatile organic compounds related to meat spoilage.The collagenase((hemagglutinin protease(Hap))secreted by NCM 29 has been identified as the key factor responsible for the observed discrepancies in spoilage,which gradually degraded collagen into peptides and hydroxyproline.The capacity of Hap to degrade type Ⅰ collagen in vitro indicated that it has apparent proteolytic activity,which could reduce the average particle size and alter secondary structure of collagen.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)further confirmed the degradation of theβ-chain in collagen.These findings not only provide a theoretical basis for in-depth investigation of the meat spoilage mechanisms of Aeromonas spp.,but also encourage us to take measures to avoid the spoilage of related bacteria such as Aeromonas spp.during the preservation process.
基金M.A.F.acknowledges the financing support by Universidad Nacional del Sur(Grant No.PGI 24/Q112 and Grant No.PICT 2021-I-A-00288)Agencia Nacional de Promoción Científica y Tecnológica(ANPCyT)(Grant No.PIP 2021-2023 GI 11220200100317CO).
文摘This review article provides a comprehensive examination of the most recent advances in research on nanoglasses,including the methods used to create these materials,their characteristics,and their diverse range of uses.An overview of the current trends in nanoglass research connects them to the Sustainable Development Goals,highlighting the current relevance of this topic.The process of manufacturing nanoglasses is explained in depth,highlighting advanced approaches such as inert gas condensation and severe plastic deformation,among other techniques.The prime focus of this review is on analyzing the various dimensions of nanoglass materials,including their structural dynamics and electrical configurations,and how these features contribute to their exceptional thermal stability and mechanical strength.The magnetic characteristics of nanoglasses are examined,highlighting their potential for driving innovation across multiple industries.The primary emphasis is on the biological usefulness of nanoglasses,specifically examining their bioactivity and interaction with biological components,and emphasizing their growing use in nanoscale biomedical applications.With regard to the practical applications of nanoglasses,there are specific discussions of their contributions to biological evaluation,wound healing,catalysis,and environmental sustainability.There is an emphasis on the durability and resistance of nanoglasses in these contexts.The comprehensive overview of nanoglasses provided in this article highlights their significance as revolutionary materials in fields of science and technology.The potential of nanoglasses to contribute to a future that is more sustainable and health oriented is indicated.The article ends by discussing the future directions for nanoglass research and looks forward to the promising possibilities for further investigation and innovation.
基金supported by the National Natural Science Foundation of China(52301177)。
文摘The advancement of electron microscopy technology has driven the development of electron microscopes that can apply mechanical loading while observing samples,providing a valuable tool for In-Situ mechanical characterization of materials.In response to the need to characterize the evolution of the mechanical behavior of structural materials,such as aerospace materials,in real cryogenic service environments,and to provide an experimental basis for improving their macroscopic cryogenic mechanical properties,the advancement of In-Situ characterization techniques capable of offering both cryogenic environments and mechanical loading has become imperative.There have been scholars using this technique to carry out cryogenic mechanical In-Situ studies of related materials,with experimental studies dominating in general,and a few reviews of mechanical characterization techniques mentioning cryogenic temperatures.In order to make it easier to conduct research using such characterization techniques and to further promote the development of related characterization techniques,this review compiles the previous work and summarizes the electron microscope-based In-Situ characterization techniques for cryogenic micro-and nanomechanics.These techniques primarily include transmission electron microscopy-based cryogenic tensile and indentation methods,as well as scanning electron microscopy-based cryogenic tensile,indentation,compression,and bending methods.Furthermore,the review outlines the prospective future development of In-Situ characterization techniques for cryogenic micro-and nanomechanics.
文摘Research-based on lignin as a bioproduct has grown due to its high availability,reactivity,physicochemical sta-bility,and abundance of different aromatic units.Lignin consists of various functional groups,which can react in various chemical reactions and serve as a raw material in various processes to obtain multiple products.These characteristics make lignin suitable for synthesizing products from natural raw materials,replacing fossil ones.Due to a high aromatic variety and complex structural arrangement,lignin isolation and fractionation are still challenging.The aim and novelty of this work was the modification of severity and enzymatic hydrolysis proce-dure on an industrial pre-treatment to improve by-products of birch processing as a raw material for the potential production of different products.Lignin from birch wood enzymatic hydrolysis was obtained and marked accord-ingly:HS(high severity),MS(medium severity),and LS(low severity)lignin.Samples were characterized by ash content,analytical pyrolysis,solubility,and viscosity.HS lignin was characterized by a relatively high carbohy-drate content(16%)and lower lignin content(77%).Meanwhile,LS lignin showed increased lignin content(83%)and reduced carbohydrate content(9%).It can be concluded that the delignification process greatly influ-ences the properties of the obtained lignin.HS lignin resulted in a lower polydispersity index(PDI)and more condensed structure,while LS lignin showed a higher PDI but a lower content of carbohydrates.Therefore,look-ing for a golden middle way is necessary whilefinding the conditions according to the usefield.
基金supported by the National Natural Science Foundation of China(32201994)。
文摘Sea buckthorn(Hippophae rhamnoides L.)is a natural homologous substance of medicine and food.Polysaccharide,as one of its primary active components,has very superior biological activity and can be used as a dietary supplement for functional foods,with good commercial prospects.Although initial progress has been made in the study of sea buckthorn polysaccharides,related studies have been fragmented and lacked systematic and generalization.This manuscript presents a critical analysis and systematic summary of the extraction and purification methods,structural characterization and physicochemical properties,biological activity and potential mechanisms,and structure-activity relationships of sea buckthorn polysaccharides.Accumulating evidence has indicated that sea buckthorn polysaccharides,which were widely prepared by water extraction and column chromatography purifications,exhibited exhibit superior biological activities in vitro and in vivo,including antioxidant,immunomodulatory,anti-inflammatory,hepatorenal protective,antibacterial,antiviral,and prebiotic activities.After analysis,it was concluded that there is a correlation between the relevant activities of sea buckthorn polysaccharides and that the structure of sea buckthorn polysaccharides has a great influence on their biological activity.We reviewed the challenges and limitations of sea buckthorn polysaccharides,summarized the critical aspects,and provided suggestions for potential breakthroughs in the research and application of sea buckthorn polysaccharide.
基金supported by the Suranaree University of Technology(SUT)Center of Excellence(CoE)on Advanced Functional Materials(AFM),School of Physics,Suranaree University of Technology,Nakhon Ratchasima,Thailand,the External Grants and Scholarships for Graduate Students,Suranaree University of Technology,Nakhon Ratchasima,Thailand,and the Research Network on Nanotechnology(RNN),Suranaree University of Technology,Nakhon Ratchasima,Thailand.
文摘High-purity SiO_(2)nanoparticles(SNPs)play a crucial role in various electronic applications,such as semiconductors,solar cells,optical fibers,lenses,and insulating layers,given their purity and particle size,which significantly impact device efficiency.This study fo-cuses on the synthesis and characterization of pure SNPs through the chemical etching of greater club rush.White powder SNPs were pre-pared using HCl etching,and their thermal behaviors were analyzed via thermogravimetric analysis/differential scanning calorimetry.Structural properties were investigated using X-ray fluorescence,scanning electron microscopy,and transmission electron microscopy.X-ray absorption near-edge structure was employed to assess the oxidation state of the SNPs.The morphology of the SNPs after the first etching was amorphous,with sizes ranging from 50 to 100 nm,which increased to 50-200 nm after the second etching.Despite this size variation,the SNPs maintained a high purity level of 99.8wt%SiO_(2),comparable with industry standards.Notably,the second etching with 0.1-M HCl significantly enhanced the purity level,achieving 99.8wt%SiO_(2)mass.Furthermore,HCl etching facilitated the formation of SiO_(2)in the Si^(4+)oxidation state,akin to industrial SNPs.These findings underscore the critical role of HCl etching in synthesizing high-purity SNPs,with potential applications in advanced electronic devices.
基金supported by the Fundamental Research Funds for the Central Universities(No.2042023kf0094)the National Key Research and Development Program of China(No.2022YFA1502902)the National Natural Science Foundation of China(No.22101217).
文摘As a novel two-dimensional(2D)material,MXenes are anticipated to have a significant impact on future aqueous energy storage and conversion technologies owing to their unique intrinsic laminar structure and exceptional physicochemical properties.Nevertheless,the fabrication and utilization of functional MXenebased devices face formidable challenges due to their susceptibility to oxidative degradation in aqueous solutions.This review begins with an outline of various preparation techniques for MXenes and their implications for structure and surface chemistry.Subsequently,the controversial oxidation mechanisms are discussed,followed by a summary of currently employed oxidation characterization techniques.Additionally,the factors influencing MXene oxidation are then introduced,encompassing chemical composition(types of M,X elements,layer numbers,terminations,and defects)as well as environment(atmosphere,temperature,light,potential,solution pH,free water and O_(2)content).The review then shifts its focus to strategies aiming to prevent or delay MXene oxidation,thereby expanding the applicability of MXenes in complex environments.Finally,the challenges and prospects within this rapidly-growing research field are presented to promote further advancements of MXenes in aqueous storage systems.
