Recently,hollow carbon nanospheres(HCSs)have garnered significant attention as potential Li metal hosts owing to their unique large voids and ease of fabrication.However,similar to other nanoscale hosts,their practica...Recently,hollow carbon nanospheres(HCSs)have garnered significant attention as potential Li metal hosts owing to their unique large voids and ease of fabrication.However,similar to other nanoscale hosts,their practical performance is limited by inhomogeneous agglomeration,increased binder requirements,and high tortuosity within the electrode.To overcome these problems and high tortuosity within the electrode,this study introduces a pomegranate-like carbon microcluster composed of primary HCSs(P-CMs)as a novel Li metal host.This unique nanostructure can be easily prepared using the spray-drying technique,enabling its mass production.Comprehensive analyses with various tools demonstrate that compared with HCS hosts,the P-CM host requires a smaller amount of binder to fabricate a sufficiently robust and even surface electrode.Furthermore,owing to reduced tortuosity,the well-designed P-CM electrode can provide continuous and shortened pathways for electron/ion transport,accelerating the Li-ion transfer kinetics and prohibiting preferential Li plating at the upper region of the electrode.Due to these characteristics,Li metal can be effectively encapsulated in the large inner voids of the primary HCSs constituting the P-CM,thereby enhancing the electrochemical performance of P-CM hosts in Li metal batteries.Specifically,the Coulombic efficiency of the P-CM host can be maintained at 97%over 100 cycles,with a high Li deposition areal capacity of 3 mAh·cm^(-2)and long cycle life(1000 h,1 mA·cm^(-2),and 1.0 mAh·cm^(-2)).Furthermore,a full cell incorporating a LiFePO4 cathode exhibits excellent cycle life.展开更多
K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require f...K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require further investigation.In this study,novel N-doped multichannel carbon nanofibers(h-NMCNFs)with hierarchical porous structures were successfully synthesized as efficient cathode hosts for K–Se batteries through the carbonization of two electrospun immiscible polymer nanofibers and subsequent chemical activation.Mesopores originated from the decomposition of the polymer embedded in the carbon nanofibers,and micropores were introduced via KOH activation.During the activation step,hierarchical porous carbon nanofibers with enhanced pore volumes were formed because of the micropores in the carbon nanofibers.Owing to the mesopores that enabled easy access to the electrolyte and the high utilization of chain-like Se within the micropores,the Se-loaded hierarchical porous carbon nanofibers(60 wt%Se)exhibited a high discharge capacity and excellent rate performance.The discharge capacity of the nanofibers at the 1,000th cycle was 210.8 mA.h.g^(-1)at a current density of 0.5C.The capacity retention after the initial activation was 64%.In addition,a discharge capacity of 165 mA.h.g^(-1)was obtained at an extremely high current density of 3.0C.展开更多
Aqueous Zn-ion batteries (AZIBs) have received considerable attention owing to their various advantages such as safety,low cost,simple battery assembly conditions,and high ionic conductivity.However,they still suffer ...Aqueous Zn-ion batteries (AZIBs) have received considerable attention owing to their various advantages such as safety,low cost,simple battery assembly conditions,and high ionic conductivity.However,they still suffer from serious problems,including uncontrollable dendrite growth,corrosion,hydrogen evolution reaction (HER) from water decomposition,electrode passivation,and unexpected by-products.The creation of a uniform artificial nanocrystal layer on the Zn anode surface is a promising strategy for resolving these issues.Herein,we propose the use of a perovskite CaTiO_(3)(CTO) protective layer on Zn(CTO@Zn) as a promising approach for improving the performance of AZIBs.The CTO artificial layer provides an efficient pathway for Zn ion diffusion towards the Zn metal because of the high dielectric constant (εr=180) and ferroelectric characteristics that enable the alignment of dipole moments and redistribute the Zn^(2+)ions in the CTO layer.By avoiding the direct contact of the Zn anode with the electrolyte solution,the uneven dendrite growth,corrosion,parasitic side reactions,and HER are mitigated,while CTO retains its mechanical and chemical robustness during cycling.Consequently,CTO@Zn demonstrates an improved lifespan in a symmetric cell configuration compared with bare Zn.CTO@Zn shows steady overpotential (~68 m V) for 1500 h at 1 mA cm^(-2)/0.5 mA h cm^(-2),excelling bare Zn.Moreover,when paired with the V_(2)O_(5)-C cathode,the CTO@Zn//V_(2)O_(5)-C full battery delivers 148.4 mA h g^(-1)(based on the mass of the cathode) after 300 cycles.This study provides new insights into Zn metal anodes and the development of high-performance AZIBs.展开更多
With mineral-melt thermobarometers,reconstruction of P-T-depth history of magmas can be established for vol-canic rocks.The pillow lava of Hantangang River Basalt is suitable for the study as it bears narrow compositi...With mineral-melt thermobarometers,reconstruction of P-T-depth history of magmas can be established for vol-canic rocks.The pillow lava of Hantangang River Basalt is suitable for the study as it bears narrow compositional range resulting from little or no fractional crystallization or crustal assimilation and shows evidence of rapid magma ascent.The established thermodynamic model covers the pathway from the magma source depth to the eruption.The model shows that the pillow lava originated at the depths of~85-100 km by fluid ascent from a stagnant slab.This range corresponds to the depth that encompasses the uppermost asthenosphere to the lowermost lithosphere corresponding to the upper garnet to the lower spinel sta-bility fields of the mantle.Subsequently,the melt rose to~66-71 km depth where a primary magma reservoir was generated possibly due to existence of a possible local discontinuity within the upper mantle.The magma uprose rapidly from~61 to~20 km or even to a shallower depth with crystallization of dendritic clinopyroxene and titano-magnetite,due to dehydration of magma.Magma ascent slowed down near the surface possibly due to the volcanic channel split into two or more toward the vents.The model can be applied to other volcanic areas composed of less evolved rocks.展开更多
This article introduces a three-parameter Lehman-type t distribution having 2 degrees of freedom,that is capable of fitting positive and negative skewed data sets.It is shown that the density and hazard functions of t...This article introduces a three-parameter Lehman-type t distribution having 2 degrees of freedom,that is capable of fitting positive and negative skewed data sets.It is shown that the density and hazard functions of the proposed distribution are uni-model.Ordinary moments,entropy measure,ordering,identifiability and order statistics are investigated.Since the quantile function is explicitly defined,quantile-based statistics are also discussed for the proposed distribution.These properties include measures of skewness and kurtosis,L-moments,quantile density and hazard functions,mean residual life function and Parzen's score function.Mechanisms of maximum likelihood,bias correction and matching of percentiles are employed for estimating the unknown parameters of the distribution.Simulation experiments are conducted to compare the performance of these three estimation methods.A real-life data set consisting of strength of glass fibres is fitted to show the adequacy of the proposed distribution over some extensions of the normal and t distributions.Parametric regression model is developed along with its parameter estimation using the maximum likelihood approach.Simulation study for the regression model is also presented that endorsed the asymptotic properties of the estimators.展开更多
The lithium(Li)metal anode is regarded as the upcoming generation of battery anodes due to its high theoretical capacity(3860 mAh g^(-1))and low standard reduction potential(-3.04 vs SHE).Addressing challenges related...The lithium(Li)metal anode is regarded as the upcoming generation of battery anodes due to its high theoretical capacity(3860 mAh g^(-1))and low standard reduction potential(-3.04 vs SHE).Addressing challenges related to the formation of Li metal dendrites,such as short circuits and low Coulombic efficiency,is crucial for the practical implementation of Li metal anodes.Previous research on Li metal has primarily focus on the Li plating process for achieving homogeneous growth.However,our study highlights the significance of pit formation variations,which significantly influence Li growth behavior in subsequent cycles.Expanding on this understanding,we formulated electrochemical activation conditions to promote uniform pit formation,thereby doubling the cycle life in a symmetric cell,and increasing the capacity retention of NCM622||Li full-cell from 68.7%to 79.5%after 500 cycles.展开更多
CoFe-Prussian blue analog(CoFe-PBA)template derived porous nanocages comprising hollow(Co,Fe)O nanoparticles are introduced as a highly efficient anode for lithium-ion batteries(LIBs)by integrat-ing the co-precipitati...CoFe-Prussian blue analog(CoFe-PBA)template derived porous nanocages comprising hollow(Co,Fe)O nanoparticles are introduced as a highly efficient anode for lithium-ion batteries(LIBs)by integrat-ing the co-precipitation and nanoscale Kirkendall diffusion processes.This strategic approach employs a solution-based facile polydopamine(PDA)-derived carbon coating process to control the oxidation rate of nanoparticles during subsequent heat treatment to achieve the hollow structure by the nanoscale Kirk-endall diffusion effect.The application of different concentrations of PDA to the nanocages resulted in the formation of porous nanocages of three types,such as(Co,Fe)O@PDA-C-20,(Co,Fe)O@PDA-C-100,and(Co,Fe)O@PDA-C-200.Notably,(Co,Fe)O@PDA-C-100 porous nanocages exhibit remarkable cycling stability by the hollow structured(Co,Fe)O nanoparticles.Additionally,the hollow and porous structures facilitate rapid charge species diffusion,efficient electrolyte infiltration,and effective management of volumetric changes.When used as anodes for LIBs,the hollow(Co,Fe)O@PDA-C-100 anodes demonstrate impressive structural robustness and high-rate performance.They exhibit remarkable structural integrity,demon-strating stable cycling performance for up to 300 cycles at 0.5 and 1.0 A g^(-1)(capacity retentions of 99.3%and 97.2%,respectively).In terms of rate capability,the hollow(Co,Fe)O@PDA-C-100 porous nanocages exhibit a high discharge capacity of 284 mA h g^(-1) at 10 A g^(-1).Moreover,the practical application po-tential of the prepared hollow(Co,Fe)O@PDA-C-100 anode is demonstrated by a full-cell test paired with and Li(Ni0.8Co0.1Mn0.1)O2 cathode under the condition of practical application.This clearly highlights the structural advantages of the prepared hollow(Co,Fe)O@PDA-C-100 porous nanocages.展开更多
Background Extracellular vesicles(EVs)regulate cell metabolism and various biological processes by delivering spe-cific proteins and nucleic acids to surrounding cells.We aimed to investigate the effects of the cargo ...Background Extracellular vesicles(EVs)regulate cell metabolism and various biological processes by delivering spe-cific proteins and nucleic acids to surrounding cells.We aimed to investigate the effects of the cargo contained in EVs derived from adipose-derived stem cells(ASCs)on the porcine embryonic development.Methods ASCs were isolated from porcine adipose tissue and characterized using ASC-specific markers via flow cytometry.EVs were subsequently extracted from the conditioned media of the established ASCs.These EVs were added to the in vitro culture environment of porcine embryos to observe qualitative improvements in embryonic development.Furthermore,the proteins within the EVs were analyzed to investigate the underlying mechanisms.Results We observed a higher blastocyst development rate and increased mitochondrial activity in early stage embryos in the ASC-EVs-supplemented group than in the controls(24.8%±0.8%vs.28.6%±1.1%,respectively).The terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)assay of blastocysts also revealed signifi-cantly reduced apoptotic cells in the ASC-EVs-supplemented group.Furthermore,through proteomics,we detected the proteins in ASC-EVs and blastocysts from each treatment group.This analysis revealed a higher fraction of pro-teins in the ASC-EVs-supplemented group than in the controls(1,547 vs.1,495,respectively).Gene analysis confirmed that ASC-EVs showed a high expression of tyrosine-protein kinase(SRC),whereas ASC-EVs supplemented blastocysts showed a higher expression of Cyclin-dependent kinase 1(CDK1).SRC is postulated to activate protein kinase B(AKT),which inhibits the forkhead box O signaling pathway and activates CDK1.Subsequently,CDK1 activation influences the cell cycle,thereby affecting in vitro embryonic development.Conclusion ASC-EVs promote mitochondrial activity,which is crucial for the early development of blastocysts and vital in the downregulation of apoptosis.Additionally,ASC-EVs supply SRC to porcine blastocysts,thereby elon-gating the cell cycle.展开更多
Hybrid organic-inorganic perovskite photodetectors have gained significant attention due to their superior potential for optoelectronic applications,offering various advantages such as low-cost processing,high charge ...Hybrid organic-inorganic perovskite photodetectors have gained significant attention due to their superior potential for optoelectronic applications,offering various advantages such as low-cost processing,high charge carrier mobility,and lightweight properties.However,these perovskite photodetectors exhibit relatively low absorption in the near-infrared(NIR)range,which limits their potential applications.Here,to address this challenge,the integration of gold nanorods(Au NRs)utilizing localized surface plasmon resonance(LSPR)effects in the NIR range has been developed,leading to enhanced light absorption in the active region and higher photocurrent generation.Additionally,∼7.9 nm of thin polyethyleneimine ethoxylated(PEIE)interlayers were incorporated into the Au NR photodetectors,suppressing dark current by blocking charge injection.As a result,the synergistic effect of the Au NR/PEIE hybrid layer has led to a high-performance photodetector with a responsivity of 0.360 A/W and a detectivity of 1.81×10^(10) Jones,demonstrating a noticeable enhancement compared to the control device.Finite-difference time-domain(FDTD)simulations,morphological characterizations,and photoluminescence studies further support the mechanism for enhancing the performance of the device.We believe that our plasmon-enhanced protocol holds strong potential as a promising platform for perovskite optoelectronic devices.展开更多
AIM:To evaluate the impact of Bmi-1 on cell senescence and metastasis of human gastric cancer cell line BGC823.METHODS:Two pairs of complementary small hairpin RNA(shRNA)oligonucleotides targeting the Bmi-1gene were d...AIM:To evaluate the impact of Bmi-1 on cell senescence and metastasis of human gastric cancer cell line BGC823.METHODS:Two pairs of complementary small hairpin RNA(shRNA)oligonucleotides targeting the Bmi-1gene were designed,synthesized,annealed and cloned into the pRNAT-U6.2 vector.After DNA sequencing to verify the correct insertion of the shRNA sequences,the recombinant plasmids were transfected into BGC823 cells.The expression of Bmi-1 mRNA and protein was examined by reverse transcription-polymerase chain reaction(RT-PCR)and Western blotting.The effects of Bmi-1 knockdown on cell senescence and metastasis were determined by theβ-Gal activity assay and Boyden chamber assay,respectively.RESULTS:The double-stranded oligonucleotide fragments of Bmi-1 short interfering RNA(siRNA)cloned into pRNAT-U6.2 vector conformed to the inserted sequence.RT-PCR and Western blotting indicated that the expression levels of Bmi-1 gene mRNA and protein were markedly decreased in transfected BGC823 cells with pRNAT-U6.2-si1104 and pRNATU6.2-si1356,especially in transfected BGC823 cells with pRNAT-U6.2-si1104,compared with two control groups(empty vector and blank group).In particular,Bmi-1 protein expression was almost completely abolished in cells transfected with the recombinant vector harboring shRNA targeting the sequence GGAGGAGGTGAATGATAAA(nt1104-1122).Compared with untransfected cells and cells transfected with the empty vector,the mean percentage of senescent cells increased and the number of cells passing through the Matrigel decreased in cells transfected with the recombinant vectors.CONCLUSION:Silencing Bmi-1 by RNA interference can increase the senescent cell rate and effectively reduce the metastasis of gastric cancer cells.展开更多
HANBIT is a magnetic mirror confinement device. Recent physics experimentshave been mainly focused on identifying discharge characteristics and on getting stable plasmaproduction and operation modes, by using a 500 kW...HANBIT is a magnetic mirror confinement device. Recent physics experimentshave been mainly focused on identifying discharge characteristics and on getting stable plasmaproduction and operation modes, by using a 500 kW slot antenna system at a fixed RF frequency of 3.5MHz and varying discharge conditions such as fueling rate, RF power, and B-field intensity incentral cell. Two distinct operation modes are found to be very sensitive to the RF power as well asthe ratio of the RF frequency to the ion cyclotron frequency. A MHD interchange mode of m = - 1 isclearly observed and the stabilizing mechanism can be explained by the sideband coupling theory.展开更多
Although bismuth vanadate(BiVO4)has been promising as photoanode material for photoelectrochemical water splitting,its charge recombination issue by short charge diffusion length has led to various studies about heter...Although bismuth vanadate(BiVO4)has been promising as photoanode material for photoelectrochemical water splitting,its charge recombination issue by short charge diffusion length has led to various studies about heterostructure photoanodes.As a hole blocking layer of BiVO4,titanium dioxide(TiO_(2)) has been considered unsuitable because of its relatively positive valence band edge and low electrical conductivity.Herein,a crystal facet engineering of TiO_(2) nanostructures is proposed to control band structures for the hole blocking layer of BiVO4 nanodots.We design two types of TiO_(2) nanostructures,which are nanorods(NRs)and nanoflowers(NFs)with different(001)and(110)crystal facets,respectively,and fabricate BiVO4/TiO_(2) heterostructure photoanodes.The BiVO4/TiO_(2) NFs showed 4.8 times higher photocurrent density than the BiVO4/TiO_(2) NRs.Transient decay time analysis and time-resolved photoluminescence reveal the enhancement is attributed to the reduced charge recombination,which is originated from the formation of type II band alignment between BiVO4 nanodots and TiO_(2) NFs.This work provides not only new insights into the interplay between crystal facets and band structures but also important steps for the design of highly efficient photoelectrodes.展开更多
Zircon U–Pb and Hf isotope data integrated in this study for magmatic and metamorphic rocks fromthe Hida Belt,southwest Japan,lead to a new understanding of the evolution of the Cordilleran arc system along the ances...Zircon U–Pb and Hf isotope data integrated in this study for magmatic and metamorphic rocks fromthe Hida Belt,southwest Japan,lead to a new understanding of the evolution of the Cordilleran arc system along the ancestral margins of present-day Northeast Asia.Ion microprobe data for magmatic zircon domains from eight mafic tointermediate orthogneisses in the Tateyama and Tsunogawa areas yielded weighted mean 206Pb/238U ages spanning the entire Permian period(302–254 Ma).Under cathodoluminescence,primary magmatic growth zones in the zircon crystals were observed to be partially or completely replaced by inward-penetrating,irregularly curved featureless or weakly zoned secondary domains that mostly yielded U–Pb ages of 250–240 Ma and relatively high Th/U ratios(>0.2).These secondary domains are considered to have been formed by solid-state recrystallization during thermal overprints associated with intrusions of Hida granitoids.Available whole-rock geochemical and Sr–Nd isotope data as well as zircon age spectra corroborate that the Hida Belt comprises the Paleozoic–Mesozoic Cordilleran arc system built upon the margin of the North China Craton,together with the YeongnamMassif in southern Korea.The arcmagmatismalong this systemwas commenced in the Carboniferous and culminated in the Permian–Triassic transition period.Highly positiveεHf(t)values(>+12)of late Carboniferous to early Permian detrital zircons in the Hida paragneisses indicate that there was significant input from the depleted asthenospheric mantle and/or its crustal derivatives in the early stage of arc magmatism.On the other hand,near-chondriticεHf(t)values(+5 to−2)of magmatic zircons from late Permian Hida orthogneisses suggest a lithospheric mantle origin.Hf isotopic differences between magmatic zircon cores and the secondary rims observed in some orthogneiss samples clearly indicate that the zircons were chemically open to fluids or melts during thermal overprints.Resumed highly positive zirconεHf(t)values(>+9)shared by Early Jurassic granitoids in the Hida Belt and Yeongnam Massif may reflect reworking of the Paleozoic arc crust.展开更多
The construction of a homojunction is an effective approach for addressing issues such as slow charge separation and charge-transfer kinetics in photoanodes.In the present work,we designed a gradient Si-and Ti-doped F...The construction of a homojunction is an effective approach for addressing issues such as slow charge separation and charge-transfer kinetics in photoanodes.In the present work,we designed a gradient Si-and Ti-doped Fe_(2)O_(3) homojunction photoanode to improve the photoelectrochemical(PEC)performance of a Ti-doped Fe_(2)O_(3) photoanode.Ti-FeOOH nanocorals were synthesized using a hydrothermal process,and Si-FeOOH was grown on Ti-FeOOH nanocorals using a rapid and facile microwaveassisted(MW)technique.By varying the MW irradiation time,the thickness of the Si/Ti:Fe_(2)O_(3) photoanode was adjusted and an optimized 3-Si/Ti:Fe_(2)O_(3) photoelectrode was achieved with a significantly enhanced photocurrent density(1.37 mA cm^(-2) at 1.23 V vs.RHE)and a cathodic shift of the onset potential(150 mV)compared with that of bare Ti-Fe_(2)O_(3).This enhanced PEC performance can be ascribed to homojunction formation and Si gradient doping.The Si dopant increased the donor concentration and the formation of a homojunction improved the intrinsic built-in electric field,thereby promoting charge separation and charge transfer.Furthermore,the as-formed homojunction passivated the surfacetrapping states,consequently improving the charge transfer efficiency(60%at 1.23 VRHE)at the photoanode/electrolyte interface.These findings could pave the way for the microwave-assisted fabrication of diverse efficient homojunction photoanodes for PEC water splitting applications.展开更多
Objective:To investigate the protective effects of Nigella sativa seed extract(NSSE) against acetaminophen(APAP)-induced hepaloloxicity in TIB-73 cells and rats.Methods:Toxicity in TIB-73 cells was induced with 10 μm...Objective:To investigate the protective effects of Nigella sativa seed extract(NSSE) against acetaminophen(APAP)-induced hepaloloxicity in TIB-73 cells and rats.Methods:Toxicity in TIB-73 cells was induced with 10 μmol/L APAP and the protective effects of NSSE were evaluated at 25.50.75,100 μg/mL.For in rim examination,a total of 30 rals were equally divided into five experimental groups:normal control(vehicle),APAP(800 mg/kg body weight single IP injection) as a hepatotoxic control,and three APAP and NS pretreated(2 weeks) groups(APAP+NSSE 100 mg:APAP+NSSE 300 mg and APAP+NSSK 900 mg/kg).Results:TIB-73 cell viability was drastically decreased by(49.0±l.9)%after the 10 μmol/L APAP treatment,which also increased reactive oxygen species production.Co-treatment with NSSE at 25.50.75,and 100 μg/mL significantly improved cell viability and suppressed reactive oxygen species generation.In viro the APAP induced alterations in blood lactate levels,pH,anionic gap,and ion levels(HCO_3^-,Mg^(2+) and K^+),which tended to normalize with the NSSE pretreatment.The NSSE also significantly decreased elevated serum levels of alanine aminotransferase,aspartate aminotransferase,lactate dehydrogenase,and alkaline phosphatase induced by APAP,which correlated with decreased levels of hepatic lipid peroxidation(nialondialdehyde),increased superoxide dismutase levels,and reduced glutathione concentrations.Improved hepatic histology was also found in the treatment groups other than APAP group.Conclusions:The in vitro and in vim findings of this study demonstrated that the NSSE has protective effects against APAP-induced hepalotoxicity and metabolic disturbances by improving antioxidant activities and suppressing both lipid peroxidation and ROS generation.展开更多
The poor stability of non-noble metal catalysts in oxygen reduction reaction(ORR) is a main bottleneck that limits their big-scale application in metal-air batteries. Herein, we construct a chainmail catalyst(Co-NC-AD...The poor stability of non-noble metal catalysts in oxygen reduction reaction(ORR) is a main bottleneck that limits their big-scale application in metal-air batteries. Herein, we construct a chainmail catalyst(Co-NC-AD) with outstanding stability, via the competitive complexation and post absorption strategy,consisting of highly graphitic layers wrapped uniform-size Co nanoparticles(Co-NPs). Experiments combined with density functional theory(DFT) calculations jointly confirmed that the electron transfer occurred from the inner Co-NPs to the external graphitic layers. It facilitated the adsorption process of oxygen molecules and the hybridization of the O-2 p and C-1 p orbitals, which accelerated the ORR reaction kinetics. Consequently, our prepared Co-NC-AD shows excellent ORR activity, offered with a more positive initial potential(E_(onset)= 0.95 V) and half-wave potential(E_(1/2)= 0.86 V). The remarkable stability and resistance of methanol poisoning are merited from the protection effect of stable graphitic layers. In addition, the high electrochemical performance of Co-NC-AD-based zinc-air battery demonstrates their potential for practical applications. Therefore, our work provides new ideas for the design of nanoconfined catalysts with high stability and activity.展开更多
Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low cost.Nevertheless,the difficulty in finding appropriate electr...Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low cost.Nevertheless,the difficulty in finding appropriate electrode materials that can efficiently store the larger K ions has hindered their practical application.Herein,we report a novel anode material,N-doped multichannel carbon nanofibers embedded with porous CoS nanoprisms(CSP@NMCNF),for high-performance PIBs.The CSP@NMCNF was synthesized using a two-step strategy comprising of the electrospinning of Co acetate hydroxide nanoprism/binary polymer blend and a subsequent heat treatment.The porous CoS nanoprisms with an anisotropic morphology were well aligned along the length axis of the N-doped multichannel carbon nanofibers,thus ensuring their structural stability during the repeated charge-discharge process.In addition,numerous pores facilitated the transport of electrons and ions.Accordingly,the CSP@NMCNF anode exhibited excellent electrochemical performance,delivering a high specific capacity of 368 mAh·g^(-1)at 0.5 A·g^(-1)after 200 cycles and excellent rate capability(232 mAh·g^(-1)at 2.0 A·g^(-1)).展开更多
Numerous studies have implicated oxidative stress in the development of complications of diabetes.During hyperglycemia,production of oxidant agents such as reactive oxygen species and reactive nitrogen species increas...Numerous studies have implicated oxidative stress in the development of complications of diabetes.During hyperglycemia,production of oxidant agents such as reactive oxygen species and reactive nitrogen species increases.This process,along with a decrease in the activity of antioxidant enzymes,induces oxidative stress in the body.This redox imbalance causes damage to vital biomolecules such as proteins,lipids and DNA and results in the generation of harmful products for the body.Mechanisms associated with the creation of oxidative stress conditions and subsequently complications of diabetes are explained through several pathways such as flux through the polyol pathway,intracellular production of advanced glycation end products precursors,protein kinase-C activation,and increased activities of the hexosamine pathway.On the other hand,the study of polymorphism in the antioxidant enzymes genes indicates that some of the gene polymorphisms reduce the antioxidant power of the enzymes.This article aims to review various studies to demonstrate the effect of oxidative stress on the pathogenesis of diabetes and the positive role of antioxidants on diabetic complications.展开更多
For the global commercialization of highly efficient and stable perovskite solar cells(PSCs),it is necessary to effectively suppress the formation of various defects acting as nonradiative recombination sources in per...For the global commercialization of highly efficient and stable perovskite solar cells(PSCs),it is necessary to effectively suppress the formation of various defects acting as nonradiative recombination sources in perovskite light-harvesting materials.Interfacial defects between the charge-selective layer and the perovskite are easily formed in the solution process used to fabricate perovskite films.In addition,owing to the difference in thermal expansion coefficients between the substrate and the perovskite film,internal residual tensile stress inevitably occurs,resulting in increased nonradiative recombination.Herein,a simple compositional engineering scheme for realizing efficient and stable PSCs,which incorporates acetamidinium bromide(AABr)as an additive into the MAPbI_(3) lattice,is proposed.As an additive,AABr has been found to provide synergistic multiple passivation for both internal and interfacial defects.AABr was found to effectively release the tensile strain of the MAPbI_(3) film by forming a structure stabilized by NH-I hydrogen bonds,as evidenced by calculations based on density functional theory(DFT).Furthermore,the incorporated AABr additives created a charge carrier recombination barrier to enhance charge collection capability by reducing interfacial defects.Accordingly,a power conversion efficiency(PCE)of 20.18%was achieved using a planar device employing AABr-incorporated MAPbI_(3).This was substantially higher than the 18.32% PCE of a pristine MAPbI_(3)-based device.Notably,unencapsulated PSCs using AABr-incorporated MAPbI_(3) absorbers exhibited excellent long-term stability,maintaining>95% of initial PCE up to 1200 hours in ambient air.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.2020R1C1C1003375)。
文摘Recently,hollow carbon nanospheres(HCSs)have garnered significant attention as potential Li metal hosts owing to their unique large voids and ease of fabrication.However,similar to other nanoscale hosts,their practical performance is limited by inhomogeneous agglomeration,increased binder requirements,and high tortuosity within the electrode.To overcome these problems and high tortuosity within the electrode,this study introduces a pomegranate-like carbon microcluster composed of primary HCSs(P-CMs)as a novel Li metal host.This unique nanostructure can be easily prepared using the spray-drying technique,enabling its mass production.Comprehensive analyses with various tools demonstrate that compared with HCS hosts,the P-CM host requires a smaller amount of binder to fabricate a sufficiently robust and even surface electrode.Furthermore,owing to reduced tortuosity,the well-designed P-CM electrode can provide continuous and shortened pathways for electron/ion transport,accelerating the Li-ion transfer kinetics and prohibiting preferential Li plating at the upper region of the electrode.Due to these characteristics,Li metal can be effectively encapsulated in the large inner voids of the primary HCSs constituting the P-CM,thereby enhancing the electrochemical performance of P-CM hosts in Li metal batteries.Specifically,the Coulombic efficiency of the P-CM host can be maintained at 97%over 100 cycles,with a high Li deposition areal capacity of 3 mAh·cm^(-2)and long cycle life(1000 h,1 mA·cm^(-2),and 1.0 mAh·cm^(-2)).Furthermore,a full cell incorporating a LiFePO4 cathode exhibits excellent cycle life.
基金financially supported by the Materials/Parts Technology Development Program(No.RS-202400456324)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)by the National Research Foundation(NRF)of Korea grant(No.RS-2024-00454367)funded by the Ministry of Science and ICT(MSIT,Korea)。
文摘K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require further investigation.In this study,novel N-doped multichannel carbon nanofibers(h-NMCNFs)with hierarchical porous structures were successfully synthesized as efficient cathode hosts for K–Se batteries through the carbonization of two electrospun immiscible polymer nanofibers and subsequent chemical activation.Mesopores originated from the decomposition of the polymer embedded in the carbon nanofibers,and micropores were introduced via KOH activation.During the activation step,hierarchical porous carbon nanofibers with enhanced pore volumes were formed because of the micropores in the carbon nanofibers.Owing to the mesopores that enabled easy access to the electrolyte and the high utilization of chain-like Se within the micropores,the Se-loaded hierarchical porous carbon nanofibers(60 wt%Se)exhibited a high discharge capacity and excellent rate performance.The discharge capacity of the nanofibers at the 1,000th cycle was 210.8 mA.h.g^(-1)at a current density of 0.5C.The capacity retention after the initial activation was 64%.In addition,a discharge capacity of 165 mA.h.g^(-1)was obtained at an extremely high current density of 3.0C.
基金Basic Science Research Capacity Enhancement Project through the Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2019R1A6C1010016)Basic Science Research Program through the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education (NRF-2021R1F1A1050130)。
文摘Aqueous Zn-ion batteries (AZIBs) have received considerable attention owing to their various advantages such as safety,low cost,simple battery assembly conditions,and high ionic conductivity.However,they still suffer from serious problems,including uncontrollable dendrite growth,corrosion,hydrogen evolution reaction (HER) from water decomposition,electrode passivation,and unexpected by-products.The creation of a uniform artificial nanocrystal layer on the Zn anode surface is a promising strategy for resolving these issues.Herein,we propose the use of a perovskite CaTiO_(3)(CTO) protective layer on Zn(CTO@Zn) as a promising approach for improving the performance of AZIBs.The CTO artificial layer provides an efficient pathway for Zn ion diffusion towards the Zn metal because of the high dielectric constant (εr=180) and ferroelectric characteristics that enable the alignment of dipole moments and redistribute the Zn^(2+)ions in the CTO layer.By avoiding the direct contact of the Zn anode with the electrolyte solution,the uneven dendrite growth,corrosion,parasitic side reactions,and HER are mitigated,while CTO retains its mechanical and chemical robustness during cycling.Consequently,CTO@Zn demonstrates an improved lifespan in a symmetric cell configuration compared with bare Zn.CTO@Zn shows steady overpotential (~68 m V) for 1500 h at 1 mA cm^(-2)/0.5 mA h cm^(-2),excelling bare Zn.Moreover,when paired with the V_(2)O_(5)-C cathode,the CTO@Zn//V_(2)O_(5)-C full battery delivers 148.4 mA h g^(-1)(based on the mass of the cathode) after 300 cycles.This study provides new insights into Zn metal anodes and the development of high-performance AZIBs.
基金supported by the 2021 Research Project for UNESCO Hantangang River Global Geopark supported by Gyeonggi Provincial Office(Grant No.20210606641-00)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2019R1A6A1A03033167).
文摘With mineral-melt thermobarometers,reconstruction of P-T-depth history of magmas can be established for vol-canic rocks.The pillow lava of Hantangang River Basalt is suitable for the study as it bears narrow compositional range resulting from little or no fractional crystallization or crustal assimilation and shows evidence of rapid magma ascent.The established thermodynamic model covers the pathway from the magma source depth to the eruption.The model shows that the pillow lava originated at the depths of~85-100 km by fluid ascent from a stagnant slab.This range corresponds to the depth that encompasses the uppermost asthenosphere to the lowermost lithosphere corresponding to the upper garnet to the lower spinel sta-bility fields of the mantle.Subsequently,the melt rose to~66-71 km depth where a primary magma reservoir was generated possibly due to existence of a possible local discontinuity within the upper mantle.The magma uprose rapidly from~61 to~20 km or even to a shallower depth with crystallization of dendritic clinopyroxene and titano-magnetite,due to dehydration of magma.Magma ascent slowed down near the surface possibly due to the volcanic channel split into two or more toward the vents.The model can be applied to other volcanic areas composed of less evolved rocks.
基金the financial support from Science and Engineering Research Board,Department of Science&Technology,Government of India,under the scheme Early Career Research Award(file no.ECR/2017/002416)Dr.Sharma also acknowledges Banaras Hindu University,Varanasi,India,for providing financial support as seed grant under the Institute of Eminence Scheme(Scheme no.Dev.6031).
文摘This article introduces a three-parameter Lehman-type t distribution having 2 degrees of freedom,that is capable of fitting positive and negative skewed data sets.It is shown that the density and hazard functions of the proposed distribution are uni-model.Ordinary moments,entropy measure,ordering,identifiability and order statistics are investigated.Since the quantile function is explicitly defined,quantile-based statistics are also discussed for the proposed distribution.These properties include measures of skewness and kurtosis,L-moments,quantile density and hazard functions,mean residual life function and Parzen's score function.Mechanisms of maximum likelihood,bias correction and matching of percentiles are employed for estimating the unknown parameters of the distribution.Simulation experiments are conducted to compare the performance of these three estimation methods.A real-life data set consisting of strength of glass fibres is fitted to show the adequacy of the proposed distribution over some extensions of the normal and t distributions.Parametric regression model is developed along with its parameter estimation using the maximum likelihood approach.Simulation study for the regression model is also presented that endorsed the asymptotic properties of the estimators.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea Government(MSIT)(RS-202400422387)the National Research Foundation of Korea(NRF)grant funded by the Korea Government(MSIT)(RS-2024-00404414)support by The Ministry of Science and ICT in Korea via KBSI(Grant No.C524100).
文摘The lithium(Li)metal anode is regarded as the upcoming generation of battery anodes due to its high theoretical capacity(3860 mAh g^(-1))and low standard reduction potential(-3.04 vs SHE).Addressing challenges related to the formation of Li metal dendrites,such as short circuits and low Coulombic efficiency,is crucial for the practical implementation of Li metal anodes.Previous research on Li metal has primarily focus on the Li plating process for achieving homogeneous growth.However,our study highlights the significance of pit formation variations,which significantly influence Li growth behavior in subsequent cycles.Expanding on this understanding,we formulated electrochemical activation conditions to promote uniform pit formation,thereby doubling the cycle life in a symmetric cell,and increasing the capacity retention of NCM622||Li full-cell from 68.7%to 79.5%after 500 cycles.
基金supported by the National Research Foundation of Korea(NRF)and the Commercialization Promotion Agency for R&D Outcomes(COMPA)funded by the Ministry of Science and ICT(Nos.RS-2023-00217581 and RS-2023-00304768).
文摘CoFe-Prussian blue analog(CoFe-PBA)template derived porous nanocages comprising hollow(Co,Fe)O nanoparticles are introduced as a highly efficient anode for lithium-ion batteries(LIBs)by integrat-ing the co-precipitation and nanoscale Kirkendall diffusion processes.This strategic approach employs a solution-based facile polydopamine(PDA)-derived carbon coating process to control the oxidation rate of nanoparticles during subsequent heat treatment to achieve the hollow structure by the nanoscale Kirk-endall diffusion effect.The application of different concentrations of PDA to the nanocages resulted in the formation of porous nanocages of three types,such as(Co,Fe)O@PDA-C-20,(Co,Fe)O@PDA-C-100,and(Co,Fe)O@PDA-C-200.Notably,(Co,Fe)O@PDA-C-100 porous nanocages exhibit remarkable cycling stability by the hollow structured(Co,Fe)O nanoparticles.Additionally,the hollow and porous structures facilitate rapid charge species diffusion,efficient electrolyte infiltration,and effective management of volumetric changes.When used as anodes for LIBs,the hollow(Co,Fe)O@PDA-C-100 anodes demonstrate impressive structural robustness and high-rate performance.They exhibit remarkable structural integrity,demon-strating stable cycling performance for up to 300 cycles at 0.5 and 1.0 A g^(-1)(capacity retentions of 99.3%and 97.2%,respectively).In terms of rate capability,the hollow(Co,Fe)O@PDA-C-100 porous nanocages exhibit a high discharge capacity of 284 mA h g^(-1) at 10 A g^(-1).Moreover,the practical application po-tential of the prepared hollow(Co,Fe)O@PDA-C-100 anode is demonstrated by a full-cell test paired with and Li(Ni0.8Co0.1Mn0.1)O2 cathode under the condition of practical application.This clearly highlights the structural advantages of the prepared hollow(Co,Fe)O@PDA-C-100 porous nanocages.
基金The Ministry of Science and ICT through the National Research Foundation of Korea (NRF) supported this study (grant numbers:2021R1A2C2009294)The Research Institute for Veterinary Science at the Seoul National University partially funded this study。
文摘Background Extracellular vesicles(EVs)regulate cell metabolism and various biological processes by delivering spe-cific proteins and nucleic acids to surrounding cells.We aimed to investigate the effects of the cargo contained in EVs derived from adipose-derived stem cells(ASCs)on the porcine embryonic development.Methods ASCs were isolated from porcine adipose tissue and characterized using ASC-specific markers via flow cytometry.EVs were subsequently extracted from the conditioned media of the established ASCs.These EVs were added to the in vitro culture environment of porcine embryos to observe qualitative improvements in embryonic development.Furthermore,the proteins within the EVs were analyzed to investigate the underlying mechanisms.Results We observed a higher blastocyst development rate and increased mitochondrial activity in early stage embryos in the ASC-EVs-supplemented group than in the controls(24.8%±0.8%vs.28.6%±1.1%,respectively).The terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)assay of blastocysts also revealed signifi-cantly reduced apoptotic cells in the ASC-EVs-supplemented group.Furthermore,through proteomics,we detected the proteins in ASC-EVs and blastocysts from each treatment group.This analysis revealed a higher fraction of pro-teins in the ASC-EVs-supplemented group than in the controls(1,547 vs.1,495,respectively).Gene analysis confirmed that ASC-EVs showed a high expression of tyrosine-protein kinase(SRC),whereas ASC-EVs supplemented blastocysts showed a higher expression of Cyclin-dependent kinase 1(CDK1).SRC is postulated to activate protein kinase B(AKT),which inhibits the forkhead box O signaling pathway and activates CDK1.Subsequently,CDK1 activation influences the cell cycle,thereby affecting in vitro embryonic development.Conclusion ASC-EVs promote mitochondrial activity,which is crucial for the early development of blastocysts and vital in the downregulation of apoptosis.Additionally,ASC-EVs supply SRC to porcine blastocysts,thereby elon-gating the cell cycle.
基金supported by the National Research Foundation of Korea(NRF)Grant funded by the Korean Government(Nos.2020R1A2C3003958 and 2021R1C1C2010169)the Basic Science Research Program(Priority Research Institute)through the NRF of Korea funded by the Ministry of Education(No.2021R1A6A1A10039823)the Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Education(No.2020R1A6C101B194).
文摘Hybrid organic-inorganic perovskite photodetectors have gained significant attention due to their superior potential for optoelectronic applications,offering various advantages such as low-cost processing,high charge carrier mobility,and lightweight properties.However,these perovskite photodetectors exhibit relatively low absorption in the near-infrared(NIR)range,which limits their potential applications.Here,to address this challenge,the integration of gold nanorods(Au NRs)utilizing localized surface plasmon resonance(LSPR)effects in the NIR range has been developed,leading to enhanced light absorption in the active region and higher photocurrent generation.Additionally,∼7.9 nm of thin polyethyleneimine ethoxylated(PEIE)interlayers were incorporated into the Au NR photodetectors,suppressing dark current by blocking charge injection.As a result,the synergistic effect of the Au NR/PEIE hybrid layer has led to a high-performance photodetector with a responsivity of 0.360 A/W and a detectivity of 1.81×10^(10) Jones,demonstrating a noticeable enhancement compared to the control device.Finite-difference time-domain(FDTD)simulations,morphological characterizations,and photoluminescence studies further support the mechanism for enhancing the performance of the device.We believe that our plasmon-enhanced protocol holds strong potential as a promising platform for perovskite optoelectronic devices.
基金Supported by The Provincial Nature Science Foundation of Henan Education Department,No.2009C310007,to Gao FL
文摘AIM:To evaluate the impact of Bmi-1 on cell senescence and metastasis of human gastric cancer cell line BGC823.METHODS:Two pairs of complementary small hairpin RNA(shRNA)oligonucleotides targeting the Bmi-1gene were designed,synthesized,annealed and cloned into the pRNAT-U6.2 vector.After DNA sequencing to verify the correct insertion of the shRNA sequences,the recombinant plasmids were transfected into BGC823 cells.The expression of Bmi-1 mRNA and protein was examined by reverse transcription-polymerase chain reaction(RT-PCR)and Western blotting.The effects of Bmi-1 knockdown on cell senescence and metastasis were determined by theβ-Gal activity assay and Boyden chamber assay,respectively.RESULTS:The double-stranded oligonucleotide fragments of Bmi-1 short interfering RNA(siRNA)cloned into pRNAT-U6.2 vector conformed to the inserted sequence.RT-PCR and Western blotting indicated that the expression levels of Bmi-1 gene mRNA and protein were markedly decreased in transfected BGC823 cells with pRNAT-U6.2-si1104 and pRNATU6.2-si1356,especially in transfected BGC823 cells with pRNAT-U6.2-si1104,compared with two control groups(empty vector and blank group).In particular,Bmi-1 protein expression was almost completely abolished in cells transfected with the recombinant vector harboring shRNA targeting the sequence GGAGGAGGTGAATGATAAA(nt1104-1122).Compared with untransfected cells and cells transfected with the empty vector,the mean percentage of senescent cells increased and the number of cells passing through the Matrigel decreased in cells transfected with the recombinant vectors.CONCLUSION:Silencing Bmi-1 by RNA interference can increase the senescent cell rate and effectively reduce the metastasis of gastric cancer cells.
基金The project supported by the Korea Ministry of Science and Technology
文摘HANBIT is a magnetic mirror confinement device. Recent physics experimentshave been mainly focused on identifying discharge characteristics and on getting stable plasmaproduction and operation modes, by using a 500 kW slot antenna system at a fixed RF frequency of 3.5MHz and varying discharge conditions such as fueling rate, RF power, and B-field intensity incentral cell. Two distinct operation modes are found to be very sensitive to the RF power as well asthe ratio of the RF frequency to the ion cyclotron frequency. A MHD interchange mode of m = - 1 isclearly observed and the stabilizing mechanism can be explained by the sideband coupling theory.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(MSIT)(2021R1A2B5B03001851)the NRF Grant funded by the Korean government MSIT(2021M3H4A1A03057403).M.G.L.acknowledges the Basic Science Research Program through the NRF funded by the Ministry of Education(2021R1A6A3A03039988).J.W.Y.acknowledges the Basic Science Research Program through the NRF funded by the Ministry of Education(2021R1A6A3A13046700).
文摘Although bismuth vanadate(BiVO4)has been promising as photoanode material for photoelectrochemical water splitting,its charge recombination issue by short charge diffusion length has led to various studies about heterostructure photoanodes.As a hole blocking layer of BiVO4,titanium dioxide(TiO_(2)) has been considered unsuitable because of its relatively positive valence band edge and low electrical conductivity.Herein,a crystal facet engineering of TiO_(2) nanostructures is proposed to control band structures for the hole blocking layer of BiVO4 nanodots.We design two types of TiO_(2) nanostructures,which are nanorods(NRs)and nanoflowers(NFs)with different(001)and(110)crystal facets,respectively,and fabricate BiVO4/TiO_(2) heterostructure photoanodes.The BiVO4/TiO_(2) NFs showed 4.8 times higher photocurrent density than the BiVO4/TiO_(2) NRs.Transient decay time analysis and time-resolved photoluminescence reveal the enhancement is attributed to the reduced charge recombination,which is originated from the formation of type II band alignment between BiVO4 nanodots and TiO_(2) NFs.This work provides not only new insights into the interplay between crystal facets and band structures but also important steps for the design of highly efficient photoelectrodes.
基金jointly supported by a Basic Research Project(20-3111-1:Geological survey in the Korean Peninsula and publication of the geological maps)of the Korea Institute of Geoscience and Mineral Resources,funded by the Ministry of Science and ICT,Korearesearch grants from the Korea Basic Science Institute(C070110,C030120).
文摘Zircon U–Pb and Hf isotope data integrated in this study for magmatic and metamorphic rocks fromthe Hida Belt,southwest Japan,lead to a new understanding of the evolution of the Cordilleran arc system along the ancestral margins of present-day Northeast Asia.Ion microprobe data for magmatic zircon domains from eight mafic tointermediate orthogneisses in the Tateyama and Tsunogawa areas yielded weighted mean 206Pb/238U ages spanning the entire Permian period(302–254 Ma).Under cathodoluminescence,primary magmatic growth zones in the zircon crystals were observed to be partially or completely replaced by inward-penetrating,irregularly curved featureless or weakly zoned secondary domains that mostly yielded U–Pb ages of 250–240 Ma and relatively high Th/U ratios(>0.2).These secondary domains are considered to have been formed by solid-state recrystallization during thermal overprints associated with intrusions of Hida granitoids.Available whole-rock geochemical and Sr–Nd isotope data as well as zircon age spectra corroborate that the Hida Belt comprises the Paleozoic–Mesozoic Cordilleran arc system built upon the margin of the North China Craton,together with the YeongnamMassif in southern Korea.The arcmagmatismalong this systemwas commenced in the Carboniferous and culminated in the Permian–Triassic transition period.Highly positiveεHf(t)values(>+12)of late Carboniferous to early Permian detrital zircons in the Hida paragneisses indicate that there was significant input from the depleted asthenospheric mantle and/or its crustal derivatives in the early stage of arc magmatism.On the other hand,near-chondriticεHf(t)values(+5 to−2)of magmatic zircons from late Permian Hida orthogneisses suggest a lithospheric mantle origin.Hf isotopic differences between magmatic zircon cores and the secondary rims observed in some orthogneiss samples clearly indicate that the zircons were chemically open to fluids or melts during thermal overprints.Resumed highly positive zirconεHf(t)values(>+9)shared by Early Jurassic granitoids in the Hida Belt and Yeongnam Massif may reflect reworking of the Paleozoic arc crust.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(NRF-2021R1A2C1095669 and NRF-2021R1F1A104936)。
文摘The construction of a homojunction is an effective approach for addressing issues such as slow charge separation and charge-transfer kinetics in photoanodes.In the present work,we designed a gradient Si-and Ti-doped Fe_(2)O_(3) homojunction photoanode to improve the photoelectrochemical(PEC)performance of a Ti-doped Fe_(2)O_(3) photoanode.Ti-FeOOH nanocorals were synthesized using a hydrothermal process,and Si-FeOOH was grown on Ti-FeOOH nanocorals using a rapid and facile microwaveassisted(MW)technique.By varying the MW irradiation time,the thickness of the Si/Ti:Fe_(2)O_(3) photoanode was adjusted and an optimized 3-Si/Ti:Fe_(2)O_(3) photoelectrode was achieved with a significantly enhanced photocurrent density(1.37 mA cm^(-2) at 1.23 V vs.RHE)and a cathodic shift of the onset potential(150 mV)compared with that of bare Ti-Fe_(2)O_(3).This enhanced PEC performance can be ascribed to homojunction formation and Si gradient doping.The Si dopant increased the donor concentration and the formation of a homojunction improved the intrinsic built-in electric field,thereby promoting charge separation and charge transfer.Furthermore,the as-formed homojunction passivated the surfacetrapping states,consequently improving the charge transfer efficiency(60%at 1.23 VRHE)at the photoanode/electrolyte interface.These findings could pave the way for the microwave-assisted fabrication of diverse efficient homojunction photoanodes for PEC water splitting applications.
基金supported in part by the Brain Korea 21 Plus program of the National Research Foundation of Korea Grant
文摘Objective:To investigate the protective effects of Nigella sativa seed extract(NSSE) against acetaminophen(APAP)-induced hepaloloxicity in TIB-73 cells and rats.Methods:Toxicity in TIB-73 cells was induced with 10 μmol/L APAP and the protective effects of NSSE were evaluated at 25.50.75,100 μg/mL.For in rim examination,a total of 30 rals were equally divided into five experimental groups:normal control(vehicle),APAP(800 mg/kg body weight single IP injection) as a hepatotoxic control,and three APAP and NS pretreated(2 weeks) groups(APAP+NSSE 100 mg:APAP+NSSE 300 mg and APAP+NSSK 900 mg/kg).Results:TIB-73 cell viability was drastically decreased by(49.0±l.9)%after the 10 μmol/L APAP treatment,which also increased reactive oxygen species production.Co-treatment with NSSE at 25.50.75,and 100 μg/mL significantly improved cell viability and suppressed reactive oxygen species generation.In viro the APAP induced alterations in blood lactate levels,pH,anionic gap,and ion levels(HCO_3^-,Mg^(2+) and K^+),which tended to normalize with the NSSE pretreatment.The NSSE also significantly decreased elevated serum levels of alanine aminotransferase,aspartate aminotransferase,lactate dehydrogenase,and alkaline phosphatase induced by APAP,which correlated with decreased levels of hepatic lipid peroxidation(nialondialdehyde),increased superoxide dismutase levels,and reduced glutathione concentrations.Improved hepatic histology was also found in the treatment groups other than APAP group.Conclusions:The in vitro and in vim findings of this study demonstrated that the NSSE has protective effects against APAP-induced hepalotoxicity and metabolic disturbances by improving antioxidant activities and suppressing both lipid peroxidation and ROS generation.
基金supported by the National Natural Science Foundation of China(51872115,51932003)the 2020 International Cooperation Project of the Department of Science and Technology of Jilin Province(20200801001GH)+1 种基金the Project supported by State Key Laboratory of Luminescence and Applications(KLA-2020-05)the Project for Self-innovation Capability Construction of Jilin Province Development and Reform Commission(2021C026)。
文摘The poor stability of non-noble metal catalysts in oxygen reduction reaction(ORR) is a main bottleneck that limits their big-scale application in metal-air batteries. Herein, we construct a chainmail catalyst(Co-NC-AD) with outstanding stability, via the competitive complexation and post absorption strategy,consisting of highly graphitic layers wrapped uniform-size Co nanoparticles(Co-NPs). Experiments combined with density functional theory(DFT) calculations jointly confirmed that the electron transfer occurred from the inner Co-NPs to the external graphitic layers. It facilitated the adsorption process of oxygen molecules and the hybridization of the O-2 p and C-1 p orbitals, which accelerated the ORR reaction kinetics. Consequently, our prepared Co-NC-AD shows excellent ORR activity, offered with a more positive initial potential(E_(onset)= 0.95 V) and half-wave potential(E_(1/2)= 0.86 V). The remarkable stability and resistance of methanol poisoning are merited from the protection effect of stable graphitic layers. In addition, the high electrochemical performance of Co-NC-AD-based zinc-air battery demonstrates their potential for practical applications. Therefore, our work provides new ideas for the design of nanoconfined catalysts with high stability and activity.
基金financially supported by a National Research Foundation of Korea(NRF)from the Korean government(MSIT)(No.2020R1C1C1003375)。
文摘Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low cost.Nevertheless,the difficulty in finding appropriate electrode materials that can efficiently store the larger K ions has hindered their practical application.Herein,we report a novel anode material,N-doped multichannel carbon nanofibers embedded with porous CoS nanoprisms(CSP@NMCNF),for high-performance PIBs.The CSP@NMCNF was synthesized using a two-step strategy comprising of the electrospinning of Co acetate hydroxide nanoprism/binary polymer blend and a subsequent heat treatment.The porous CoS nanoprisms with an anisotropic morphology were well aligned along the length axis of the N-doped multichannel carbon nanofibers,thus ensuring their structural stability during the repeated charge-discharge process.In addition,numerous pores facilitated the transport of electrons and ions.Accordingly,the CSP@NMCNF anode exhibited excellent electrochemical performance,delivering a high specific capacity of 368 mAh·g^(-1)at 0.5 A·g^(-1)after 200 cycles and excellent rate capability(232 mAh·g^(-1)at 2.0 A·g^(-1)).
文摘Numerous studies have implicated oxidative stress in the development of complications of diabetes.During hyperglycemia,production of oxidant agents such as reactive oxygen species and reactive nitrogen species increases.This process,along with a decrease in the activity of antioxidant enzymes,induces oxidative stress in the body.This redox imbalance causes damage to vital biomolecules such as proteins,lipids and DNA and results in the generation of harmful products for the body.Mechanisms associated with the creation of oxidative stress conditions and subsequently complications of diabetes are explained through several pathways such as flux through the polyol pathway,intracellular production of advanced glycation end products precursors,protein kinase-C activation,and increased activities of the hexosamine pathway.On the other hand,the study of polymorphism in the antioxidant enzymes genes indicates that some of the gene polymorphisms reduce the antioxidant power of the enzymes.This article aims to review various studies to demonstrate the effect of oxidative stress on the pathogenesis of diabetes and the positive role of antioxidants on diabetic complications.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2020R1F1A1068664)。
文摘For the global commercialization of highly efficient and stable perovskite solar cells(PSCs),it is necessary to effectively suppress the formation of various defects acting as nonradiative recombination sources in perovskite light-harvesting materials.Interfacial defects between the charge-selective layer and the perovskite are easily formed in the solution process used to fabricate perovskite films.In addition,owing to the difference in thermal expansion coefficients between the substrate and the perovskite film,internal residual tensile stress inevitably occurs,resulting in increased nonradiative recombination.Herein,a simple compositional engineering scheme for realizing efficient and stable PSCs,which incorporates acetamidinium bromide(AABr)as an additive into the MAPbI_(3) lattice,is proposed.As an additive,AABr has been found to provide synergistic multiple passivation for both internal and interfacial defects.AABr was found to effectively release the tensile strain of the MAPbI_(3) film by forming a structure stabilized by NH-I hydrogen bonds,as evidenced by calculations based on density functional theory(DFT).Furthermore,the incorporated AABr additives created a charge carrier recombination barrier to enhance charge collection capability by reducing interfacial defects.Accordingly,a power conversion efficiency(PCE)of 20.18%was achieved using a planar device employing AABr-incorporated MAPbI_(3).This was substantially higher than the 18.32% PCE of a pristine MAPbI_(3)-based device.Notably,unencapsulated PSCs using AABr-incorporated MAPbI_(3) absorbers exhibited excellent long-term stability,maintaining>95% of initial PCE up to 1200 hours in ambient air.
