Observational analyses and convection-permitting simulations are conducted to study an extreme event of damaging surface winds within a bow-shaped squall line over South China.Prevailing explanations for the formation...Observational analyses and convection-permitting simulations are conducted to study an extreme event of damaging surface winds within a bow-shaped squall line over South China.Prevailing explanations for the formation of damaging surface winds were applied to investigate the detailed processes at the mature stage of a squall line in a complicated real-world scenario.It is shown that environmental vertical wind shear was adequately strong to cause a shearing vorticity,and the shearing vorticity was comparable to the baroclinic vorticity by a cold pool.The balance led to strong upward motions at the leading edge of the squall line and brought plenty of rainfall.The descending rainfall cooled the surrounding air and entrained the upper-level cold air downward to the lower level,strengthening the cold pool by excessive evaporation and melting.The cold pool accelerated the propagation speed of the squall line and caused extensive wind damage at the surface.Meanwhile,the horizontal vortex lines at the leading edge of the cold pool were lifted by frontal updrafts and tilted to form the anti-cyclonic vortex at the middle level.This maintained and intensified the rearinflow jet behind the apex of bow echo in association with a notable midlevel pressure gradient.The rear-inflow jet was then transported downward to the surface by descending condensate,leading to damaging winds there.Other factors,such as environmental flows,however,contributed less to the damaging surface winds.展开更多
The use of conventional herbal medicines is a rapidly expanding phenomenon in developed nations. For instance, 30%–50% of all drug use in China is attributed to traditional herbal preparations. Current study evaluate...The use of conventional herbal medicines is a rapidly expanding phenomenon in developed nations. For instance, 30%–50% of all drug use in China is attributed to traditional herbal preparations. Current study evaluated the antioxidant (DPPH, FRAP), total phenolic and flavonoid content, antibacterial activity, and DNA damage protective potential of aqueous and methanolic extracts obtained from the aerial parts and roots of Cymbocarpum wiedemannii Boiss., an endemic plant in Turkey. In antioxidant analyses, the methanolic extract of the aerial parts showed the highest %DPPH (73.38) and IC50 (3.46 mg/mL) values. The FRAP analysis revealed the highest iron-reducing capacity in the methanolic extract of the aerial parts (108.10 ± 0.11 mg FeSO4/mL). The aqueous extract of the aerial parts exhibited the highest total phenolic content (1.69 ± 0.02 mg gallic acid/mL), while the methanolic extract of the aerial parts had the highest total flavonoid content (13.53 ± 0.09 mg rutin/mL). Antibacterial activity tests showed no significant effect at a concentration of 1 mg/mL for the samples. DNA protective effects were tested on pBR322 plasmid DNA, demonstrating that both aerial and root extracts could protect DNA from Fenton reaction-induced damage. In conclusion, C. wiedemannii exhibits potential bioactive properties, particularly in terms of its antioxidant and DNA protective effects.展开更多
A mesoscale convective system(MCS) occurred over the East China coastal provinces and the East China Sea on 30April 2021, producing damaging surface winds near the coastal city Nantong with observed speeds reaching 45...A mesoscale convective system(MCS) occurred over the East China coastal provinces and the East China Sea on 30April 2021, producing damaging surface winds near the coastal city Nantong with observed speeds reaching 45 m s^(–1). A simulation using the Weather Research and Forecasting model with a 1.5-km grid spacing generally reproduces the development and subsequent organization of this convective system into an MCS, with an eastward protruding bow segment over the sea. In the simulation, an east-west-oriented high wind swath is generated behind the gust front of the MCS. Descending dry rear-to-front inflows behind the bow and trailing gust front are found to feed the downdrafts in the main precipitation regions. The inflows help to establish spreading cold outflows and enhance the downdrafts through evaporative cooling. Meanwhile, front-to-rear inflows from the south are present, associated with severely rearward-tilted updrafts initially forming over the gust front. Such inflows descend behind(north of) the gust front, significantly enhancing downdrafts and near-surface winds within the cold pool. Consistently, calculated trajectories show that these parcels that contribute to the derecho originate primarily from the region ahead(south) of the east-west-oriented gust front, and dry southwesterly flows in the low-to-middle levels contribute to strong downdrafts within the MCS. Moreover, momentum budget analyses reveal that a large westward-directed horizontal pressure gradient force within the simulated cold pool produced rapid flow acceleration towards Nantong. The analyses enrich the understanding of damaging wind characteristics over coastal East China and will prove helpful to operational forecasters.展开更多
Compound SLXM-2, a derivative of cyclophosphamide （CTX）, has shown potent growth-inhibitory effect on tumor cells with low toxicity in previous studies. However, the mechanism of its anti-tumor effect, especially on...Compound SLXM-2, a derivative of cyclophosphamide （CTX）, has shown potent growth-inhibitory effect on tumor cells with low toxicity in previous studies. However, the mechanism of its anti-tumor effect, especially on DNA damage, remains largely unclear. This study investigated the effect of SLXM-2 on the survival time of mice transplanted with the ascitie fluid-type hepatocarcinoma 22 （H22）. We also evaluated the correlation between DNA damaging effect of SLXM-2 and its anti-tumor effect, and to probe the possible molecular mechanism for its effect on H22 cells. The results suggested that SLXM-2 significantly （P〈0.05） prolonged the survival time of mice bearing the ascitic fluid-type H22. Furthermore, SLXM-2 induced DNA damage in a dose-dependent manner in H22 cells. Further investigation revealed that SLXM-2 significantly （P〈0.05） up-regulated the expression levels of a series of DNA damage-related proteins, such as γH2AX （Ser139）, p-Chkl （Ser296）, p-Chk2 （Thr68）, p-p53 （Ser15）, p-p53 （Ser20） and p21, and down-regulated the expression of p-ATR （Ser428） and p-ATM （Ser1981）. In conclusion, SLXM-2 showed a remarkable anti-tumor activity on ascitic fluid-type H22 cells, and its molecular mechanism is related to its DNA damaging effect.展开更多
Urban trees are subjected to different damaging agents throughout their lifetime. The aims of this study were to identify tree damaging agents, and to obtain a Damage Severity Index (DSI) in order to categorize tree h...Urban trees are subjected to different damaging agents throughout their lifetime. The aims of this study were to identify tree damaging agents, and to obtain a Damage Severity Index (DSI) in order to categorize tree health condition at San Juan de Aragon Park. Each tree was identified at species level in 28 randomly established plots in ten sections of the study area. Up to two types of damage were recorded per tree, based on the FIA (Forest Inventory an Analysis Program) protocol, and a DSI was obtained for each damaged tree considering location of damage, nature of the damaging agent and severity. A total of 753 trees were assessed and 12 species and 27 damaging agents were identified. Cankers, galls, the pepper tree psyllid and the red gum lerp psyllid were the most frequent damaging agents. Australian pine, red gum, Mediterranean cypress, Mexican white cedar, and California pepper were the most affected species. The DSI ranged from 3 to 17 and the average was 7.9. Sections J and H and the species California pepper, Australian pine, and Mexican white cedar presented the highest DSI. The tree population had a moderate health condition, while the aforementioned sections and tree species showed the poorest.展开更多
Autophagy plays an important role in the interaction between viruses and host cells.SARS-CoV-2 infection can disrupt the autophagy process in target cells.However,the precise molecular mechanism is still unknown.In th...Autophagy plays an important role in the interaction between viruses and host cells.SARS-CoV-2 infection can disrupt the autophagy process in target cells.However,the precise molecular mechanism is still unknown.In this study,we discovered that the Nsp8 of SARS-CoV-2 could cause an increasing accumulation of autophagosomes by preventing the fusion of autophagosomes and lysosomes.From further investigation,we found that Nsp8 was present on mitochondria and can damage mitochondria to initiate mitophagy.The results of experiments with immunofluorescence revealed that Nsp8 induced incomplete mitophagy.Moreover,both domains of Nsp8 orchestrated their function during Nsp8-induced mitophagy,in which the N-terminal domain colocalized with mitochondria and the C-terminal domain induced auto/mitophagy.This novel finding expands our understanding of the function of Nsp8 in promoting mitochondrial damage and inducing incomplete mitophagy,which helps us to understand the etiology of COVID-19 as well as open up new pathways for creating SARS-CoV-2 treatment methods.展开更多
An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation...An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation of DNA damaging chemicals. The chemicals that may cause substantial DNA damage will trigger SOS response in the constructed bacterial biosensor, and then the reporter egfp gene under the control of recA promoter is stimulated to express as a fluorescent protein, allowing fast and sensitive fluorescence detection. Interestingly, this biosensor can be simultaneously applied for evaluation of genotoxicity and cytotoxicity. The SOS-EGFP bacterial biosensor provides a sensitive, specific and simple method for detecting known and potential DNA damaging chemicals.展开更多
An improved damaging model formulated within the framework of bounding surface for structured clays was proposed. The model was intended to describe the effects of structure degradation due to geotechnical loading. Th...An improved damaging model formulated within the framework of bounding surface for structured clays was proposed. The model was intended to describe the effects of structure degradation due to geotechnical loading. The predictive capability of the model was compared with those of triaxial compression test on Tianjin soft clays. The results show that, by incorporating a new damage function into the model, the reduction of elastic bulk and shear modulus with elastic deformations and the reduction of plastic bulk modulus and shear modulus with plastic deformations are able to be appreciable. Before the axial strain reaches 15%, the axial strain computed from the model is smaller than that from the test under the drained condition. Under the undrained condition, after the axial strain reaches 1%, the axial strain increases quickly because of the complete loss of structure and stiffness; and the result computed from the model is nearly equal to that from the model without the incorporation of the damage function due to less plastic strain under undrained condition test.展开更多
The mutant effects of a keV range nitrogen ion （N＋） beam on enzyme-producing probiotics were studied, particularly with regard to the induction in the genome. The electron spin resonance （ESR） results showed that...The mutant effects of a keV range nitrogen ion （N＋） beam on enzyme-producing probiotics were studied, particularly with regard to the induction in the genome. The electron spin resonance （ESR） results showed that the signal of ESR spectrum existed in both implanted and non-implanted spores, and the yields of free radicals increased in a dose-dependent manner. The ionic etching and dilapidation of cell wall could be observed distinctly through the scanning electron microscope （SEM）. The mutagenic effect on genome indicated that N＋ implantation could make base mutation. This study provided an insight into the roles low-energy ions might play in inducing mutagenesis of micro-organisms.展开更多
The study is to assess the present serviceability rating of Nigerian highways and <span style="font-family:;" "=""><span style="font-family:Verdana;">the load damage effe...The study is to assess the present serviceability rating of Nigerian highways and <span style="font-family:;" "=""><span style="font-family:Verdana;">the load damage effects of overloaded trucks. The researchers used the American</span><span> </span><span style="font-family:Verdana;">Association of State Highway and Transportation Officials (AASHTO) methods. In this study, the highway section of Lokoja-Abuja, Ilorin-Jebba and Abakiliki-Ogoja via Mbok roads were selected, and data were collected through an axle-load survey, automatic traffic count and from secondary sources. The rate of gross vehicle weight violation was found, ranging from 20% to 94% of the axle load distribution across the studied network. Comparing the overloaded vehicle damage factor (V.D.F.) and standard V.D.F., the range was from 1.2 to 41.34 times across the road networks studied, and this explained why the pavement structures of Nigerian roads tend to deteri</span><span><span style="font-family:Verdana;">orate during its service life rapidly. Present serviceability rating was estimated at 3.45, 4.41 and 3.35 for Lokoja-Abuja, Ilorin-Jebba and Abakiliki-Ogoja roads respectively, showing depletion from their initial conditions. The damaging effects of the HGV are less severe at Lokoja-Abuja Road (with </span><i><span style="font-family:Verdana;">g</span></i><span style="font-family:Verdana;"> = 0.30), followed by </span><span><span style="font-family:Verdana;">Ilorin-Jebba Road (with </span><i><span style="font-family:Verdana;">g</span></i><span style="font-family:Verdana;"> = 0.35) and more in Abakiliki-Ogoja Road (with </span><i><span style="font-family:Verdana;">g</span></i><span style="font-family:Verdana;"> = 0.43). The heaviest overload of 94% of the 6-axle vehicles plying at the Lokoja-Abuja road could explain this intense damaging effect on the road pavement</span></span></span></span>展开更多
This study investigated the economic impact of tornadoes and damaging winds on county-level income growth in the United States from 1969 to 2023.Using a fi xed eff ect regression methodology,the analysis showed that a...This study investigated the economic impact of tornadoes and damaging winds on county-level income growth in the United States from 1969 to 2023.Using a fi xed eff ect regression methodology,the analysis showed that an average damaging storm and an average tornado reduced income growth in the aff ected counties by 0.16–0.23%and 0.21–0.23%,respectively,translating into a one-time growth loss of approximately USD 5.6 million and USD 6.3 million.The fi ndings also indicate that tornadoes have a 20%greater economic impact than damaging winds.This study underscored the unique challenges posed by tornadoes and damaging winds,which are characterized by their unpredictable nature and concentrated but extreme damage.展开更多
Objectives:SLFN11(Schlafen-11)enhances sensitivity to DNA-damaging agents(DDAs)and DNA damage response(DDR)inhibitors in various cancer types.However,its function in pancreatic cancer(PC)remains largely unknown.This r...Objectives:SLFN11(Schlafen-11)enhances sensitivity to DNA-damaging agents(DDAs)and DNA damage response(DDR)inhibitors in various cancer types.However,its function in pancreatic cancer(PC)remains largely unknown.This research aims to investigate the expression patterns of SLFN11 and other SLFN family members in PC and their correlation with drug sensitivity.Methods:SLFN11 expression and genetic alterations were analyzed using publicly available datasets(TCGA and GTEx).Functional studies,including cell cycle,apoptosis assays,and proliferation assays,were performed in SLFN11-knockdown and SLFN11-knockout(KO)PC cells.The relationship between SLFN11 expression and drug responsiveness was assessed via the CellMiner Cross-Database.Results:Analysis of multiple public datasets demonstrated that elevated SLFN11 expression is significantly linked with poor survival outcomes in PC,supporting its function as a predictive marker.Functional assays in PC cell lines demonstrated that SLFN11 knockdown disrupted G1 phase progression and increased apoptosis,indicating its involvement in tumor cell survival.Moreover,while elevated SLFN11 expression correlated with improved sensitivity to gemcitabine in some cell lines,CRISPR/Cas9-mediated SLFN11 knockout resulted in notable gemcitabine resistance.Importantly,this resistance was partially reversed when gemcitabine was combined with cisplatin and DDR inhibitors(Poly(ADP-ribose)polymerase(PARP),ataxia telangiectasia and Rad3 related(ATR),and Wee1 inhibitors),suggesting that SLFN11 modulates the reaction to both DNA-damaging agents and DDR-targeted therapies.Conclusion:Our findings indicate that SLFN11 plays a dual role in PC:as a prognostic marker,with high expression linked to poor clinical outcomes,and as a predictor of drug sensitivity,where its presence is associated with increased gemcitabine efficacy.However,the development of chemoresistance upon SLFN11 loss(and its partial reversal by DDR inhibitors)highlights the complexity of its function.These results underscore that SLFN11 expression alone may not fully determine gemcitabine response,and additional factors are likely involved.Further clinical validation is therefore essential to establish SLFN11 as a reliable biomarker for guiding DDR-targeted therapeutic strategies in PC.展开更多
Advanced microsystems in traumatic brain injury research:Traumatic brain injury(TBI)results from a mechanical insult to the brain,leading to neuronal and axonal damage and subsequently causing a secondary injury.Withi...Advanced microsystems in traumatic brain injury research:Traumatic brain injury(TBI)results from a mechanical insult to the brain,leading to neuronal and axonal damage and subsequently causing a secondary injury.Within minutes of TBI,a neuroinflammatory response is triggered,driven by intricate molecular and cellular inflammatory processes.展开更多
Investigating the combined effects of mining damage and creep damage on slope stability is crucial,as it can comprehensively reveal the non-linear deformation characteristics of rock under their joint influence.This s...Investigating the combined effects of mining damage and creep damage on slope stability is crucial,as it can comprehensively reveal the non-linear deformation characteristics of rock under their joint influence.This study develops a fractional-order nonlinear creep constitutive model that incorporates the double damage effect and implements a non-linear creep subroutine for soft rock using the threedimensional finite difference method on the FLAC3D platform.Comparative analysis of the theoretical,numerical,and experimental results reveals that the fractional-order constitutive model,which incorporates the double damage effect,accurately reflects the distinct deformation stages of green mudstone during creep failure and effectively captures the non-linear deformation in the accelerated creep phase.The numerical results show a fitting accuracy exceeding 97%with the creep test curves,significantly outperforming the 61%accuracy of traditional creep models.展开更多
The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle o...The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle on the fracture surface roughness plays an important role in estimating the damage degree and stability of deep rock mass.In this paper,the variations of fracture surface roughness of granite after different heating and thermal cycles were investigated using the joint roughness coefficient method(JRC),three-dimensional(3D)roughness parameters,and fractal dimension(D),and the mechanism of damage and deterioration of granite were revealed.The experimental results show an increase in the roughness of the granite fracture surface as temperature and cycle number were incremented.The variations of JRC,height parameter,inclination parameter and area parameter with the temperature conformed to the Boltzmann's functional distribution,while the D decreased linearly as the temperature increased.Besides,the anisotropy index(Ip)of the granite fracture surface increased as the temperature increased,and the larger parameter values of roughness characterization at different temperatures were attained mainly in directions of 20°–40°,60°–100°and 140°–160°.The fracture aperture of granite after fracture followed the Gauss distribution and the average aperture increased with increasing temperature,which increased from 0.665 mm at 25℃to 1.058 mm at 800℃.High temperature caused an uneven thermal expansion,water evaporation,and oxidation of minerals within the granite,which promoted the growth and expansion of microfractures,and reduced interparticle bonding strength.In particular,the damage was exacerbated by the expansion and cracking of the quartz phase transition after T>500℃.Thermal cycles contributed to the accumulation of this damage and further weakened the interparticle bonding forces,resulting in a significant increase in the roughness,anisotropy,and aperture of the fracture surface after five cycles.展开更多
The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagra...The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagration coupling damage model is developed to predict the penetration depth and cratering diameter.Four type of aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with densities of 2.3,2.7,3.5,and 4.5 g·cm^(-3) are selected to conduct the penetration experiments.The comparison results show that model predictions are in good agreement with the experimental data.By comparing the penetration depth and cratering diameter in the inert penetration mode and the penetration-deflagration coupling mode,the influence mechanism that the penetration-induced chemical response is unfavorable to penetration but has an enhanced cratering effect is revealed.From the formation characteristics,penetration effect and penetration-induced chemical reaction be-haviors,the influence of reactive liner density on the penetration-deflagration performance is further analyzed.The results show that increasing the density of reactive liner significantly increases both the kinetic energy and length of the reactive penetrator,meanwhile effectively reduces the weakened effect of penetration-induced chemical response,resulting in an enhanced penetration capability.However,due to the decreased diameter and potential energy content of reactive penetrator,the cratering capa-bility is weakened significantly.展开更多
The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ...The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ultimate strength.In this study,both the acoustic emission method(AEM)and the ultrasonic testing method(UTM)were used to examine the characteristics of AE parameters(b-value,peak frequency,frequency-band energy ratio,and fractal dimension)and ultrasonic(ULT)properties(velocity,amplitude,energy attenuation,and scattering attenuation)of bedded shale at CI,CD,and ultimate strength.The comparison involved analyzing the strain-based method(SBM),AEM,and UTM to determine the thresholds for damage stress.A fuzzy comprehensive evaluation model(FCEM)was created to describe the damage thresholds and hazard assessment.The results indicate that the optimal AE and ULT parameters for identifying CI and CD stress are ringing count,ultrasonic amplitude,energy attenuation,and scattering attenuation of the S-wave.Besides,damage thresholds were detected earlier by AE monitoring,ranging from 3 MPa to 10 MPa.CI and CD identified by UTM occurred later than SBM and AEM,and were in the range of 12 MPa.The b-value,peak frequency,energy ratio in the low-frequency band(0e62.5 kHz),correlation dimension,and sandbox dimension showed low values at the peak stress,while the energy ratio in a moderate-frequency band(187.5e281.25 kHz)and amplitude showed high values.The successful application of FCEM to laboratory testing of shales has demonstrated its ability to quantitatively identify AE/ULT precursors of seismic hazards associated with rock failure.展开更多
Low-to medium-maturity oil shale resources display substantial reserves, offering promising prospects for in-situ conversion inChina. Investigating the evolution of the mechanical properties of the reservoir and capro...Low-to medium-maturity oil shale resources display substantial reserves, offering promising prospects for in-situ conversion inChina. Investigating the evolution of the mechanical properties of the reservoir and caprock under in-situ high-temperature and confine-ment conditions is of considerable importance. Compared to conventional mechanical experiments on rock samples after high-temperat-ure treatment, in-situ high-temperature experiments can more accurately characterize the behavior of rocks in practical engineering,thereby providing a more realistic reflection of their mechanical properties. In this study, an in-situ high-temperature triaxial compressiontesting machine is developed to conduct in-situ compression tests on sandstone at different temperatures(25, 200, 400, 500, and 650℃)and confining pressures(0, 10, and 20 MPa). Based on the experimental results, the temperature-dependent changes in compressivestrength, peak strain, elastic modulus, Poisson's ratio, cohesion, and internal friction angle are thoroughly analyzed and discussed. Resultsindicate that the mass of sandstone gradually decreases as the temperature increases. The thermal conductivity and thermal diffusivity ofsandstone exhibit a linear relationship with temperature. Peak stress decreases as the temperature rises, while it increases with higher con-fining pressures. Notably, the influence of confining pressure on peak stress diminishes at higher temperatures. Additionally, as the tem-perature rises, the Poisson's ratio of sandstone decreases. The internal friction angle also decreases with increasing temperature, with 400℃ acting as the threshold temperature. Interestingly, under uniaxial conditions, the damage stress of sandstone is less affected by tem-perature. However, when the confining pressure is 10 or 20 MPa, the damage stress decreases as the temperature increases. This study en-hances our understanding of the influence of in-situ high-temperature and confinement conditions on the mechanical properties of sand-stone strata. The study also provides valuable references and experimental data that support the development of low-to medium-maturityoil shale resources.展开更多
Coating microdefects and localized corrosion in coating/metal system are inevitable,accelerating the degradation of metal infrastructure.Early evaluating coating microdefects and detecting corrosion sites are urgent y...Coating microdefects and localized corrosion in coating/metal system are inevitable,accelerating the degradation of metal infrastructure.Early evaluating coating microdefects and detecting corrosion sites are urgent yet remain challenge to achieve.Herein,we propose a robust,universal and efficient fluorescence-based strategy for hierarchical warning of coating damage and metal corrosion by introducing the concepts of damage-induced fluorescence enhancement effect(DIE)and ionic-recognition induced quenching effect(RIQ).The coatings with dualresponsiveness for coating defect and steel corrosion are constructed by incorporating synthesized nanoprobes composed of metal organic frameworks(Ni–Zn-MOFs)loaded with Rhodamine B(RhB@MOFs).The initial damage to the coating causes an immediate intensification of fluorescence,while the specific ionic-recognition characteristic of RhB with Fe3t results in an evident fluorescence quenching,enabling the detection of coating damage and corrosion.Importantly,this nanoprobes are insensitive to the coating matrix and exhibit stable corrosion warning capability across various coating systems.Meanwhile,electrochemical investigations indicate that the impedance values of RM/EP maintain above 10^(8)Ωcm^(2)even after 60 days of immersion.Therefore,the incorporation of fluorescent nanoprobes greatly inhibits the intrusion of electrolytes into polymer and improves the corrosion protection performance of the coating.This powerful strategy towards dual-level damage warning provides insights for the development of long-term smart protective materials.展开更多
Arsenic-related oxidative stress and resultant diseases have attracted global concern,while longitudinal studies are scarce.To assess the relationship between arsenic exposure and systemic oxidative damage,we performe...Arsenic-related oxidative stress and resultant diseases have attracted global concern,while longitudinal studies are scarce.To assess the relationship between arsenic exposure and systemic oxidative damage,we performed two repeatedmeasures among 5236 observations(4067 participants)in theWuhan-Zhuhai cohort at the baseline and follow-up after 3 years.Urinary total arsenic,biomarkers of DNA oxidative damage(8-hydroxy-2-deoxyguanosine(8-OHdG)),lipid peroxidation(8-isoprostaglandin F2alpha(8-isoPGF2α)),and protein oxidative damage(protein carbonyls(PCO))were detected for all observations.Here we used linearmixed models to estimate the cross-sectional and longitudinal associations between arsenic exposure and oxidative damage.Exposure-response curves were constructed by utilizing the generalized additive mixed models with thin plate regressions.After adjusting for potential confounders,arsenic level was significantly and positively related to the levels of global oxidative damage and their annual increased rates in dose-response manners.In cross-sectional analyses,each 1%increase in arsenic levelwas associated with a 0.406%(95%confidence interval(CI):0.379%to 0.433%),0.360%(0.301%to 0.420%),and 0.079%(0.055%to 0.103%)increase in 8-isoPGF2α,8-OHdG,and PCO,respectively.More importantly,arsenic was further found to be associated with increased annual change rates of 8-isoPGF2α(β:0.147;95%CI:0.130 to 0.164),8-OHdG(0.155;0.118 to 0.192),and PCO(0.050;0.035 to 0.064)in the longitudinal analyses.Our study suggested that arsenic exposurewas not only positively related with global oxidative damage to lipid,DNA,and protein in cross-sectional analyses,but also associated with annual increased rates of these biomarkers in dose-dependent manners.展开更多
基金Research(2020B0301030004)National Natural Science Foundation of China(42275002)+3 种基金Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0890)Scientific and Technological Project of Chongqing Meteorological Service(YWJSGG-202124)Key Innovation Team of China Meteorological Administration(CMA2022ZD09)Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP209)。
文摘Observational analyses and convection-permitting simulations are conducted to study an extreme event of damaging surface winds within a bow-shaped squall line over South China.Prevailing explanations for the formation of damaging surface winds were applied to investigate the detailed processes at the mature stage of a squall line in a complicated real-world scenario.It is shown that environmental vertical wind shear was adequately strong to cause a shearing vorticity,and the shearing vorticity was comparable to the baroclinic vorticity by a cold pool.The balance led to strong upward motions at the leading edge of the squall line and brought plenty of rainfall.The descending rainfall cooled the surrounding air and entrained the upper-level cold air downward to the lower level,strengthening the cold pool by excessive evaporation and melting.The cold pool accelerated the propagation speed of the squall line and caused extensive wind damage at the surface.Meanwhile,the horizontal vortex lines at the leading edge of the cold pool were lifted by frontal updrafts and tilted to form the anti-cyclonic vortex at the middle level.This maintained and intensified the rearinflow jet behind the apex of bow echo in association with a notable midlevel pressure gradient.The rear-inflow jet was then transported downward to the surface by descending condensate,leading to damaging winds there.Other factors,such as environmental flows,however,contributed less to the damaging surface winds.
文摘The use of conventional herbal medicines is a rapidly expanding phenomenon in developed nations. For instance, 30%–50% of all drug use in China is attributed to traditional herbal preparations. Current study evaluated the antioxidant (DPPH, FRAP), total phenolic and flavonoid content, antibacterial activity, and DNA damage protective potential of aqueous and methanolic extracts obtained from the aerial parts and roots of Cymbocarpum wiedemannii Boiss., an endemic plant in Turkey. In antioxidant analyses, the methanolic extract of the aerial parts showed the highest %DPPH (73.38) and IC50 (3.46 mg/mL) values. The FRAP analysis revealed the highest iron-reducing capacity in the methanolic extract of the aerial parts (108.10 ± 0.11 mg FeSO4/mL). The aqueous extract of the aerial parts exhibited the highest total phenolic content (1.69 ± 0.02 mg gallic acid/mL), while the methanolic extract of the aerial parts had the highest total flavonoid content (13.53 ± 0.09 mg rutin/mL). Antibacterial activity tests showed no significant effect at a concentration of 1 mg/mL for the samples. DNA protective effects were tested on pBR322 plasmid DNA, demonstrating that both aerial and root extracts could protect DNA from Fenton reaction-induced damage. In conclusion, C. wiedemannii exhibits potential bioactive properties, particularly in terms of its antioxidant and DNA protective effects.
基金primarily supported by the Ministry of Science and Technology of the People's Republic of China (MOST)(Grant No. 2018YFC1507303)National Natural Science Foundation of China (Grant Nos. 419505044,41941007, and 42230607)+1 种基金by the Talent Research Start-Up Fund of Nanjing University of Aeronautics and Astronautics(Grant No. 1007-90YAH22046)supported by The High Performance Computing Platform of Nanjing University of Aeronautics and Astronautics。
文摘A mesoscale convective system(MCS) occurred over the East China coastal provinces and the East China Sea on 30April 2021, producing damaging surface winds near the coastal city Nantong with observed speeds reaching 45 m s^(–1). A simulation using the Weather Research and Forecasting model with a 1.5-km grid spacing generally reproduces the development and subsequent organization of this convective system into an MCS, with an eastward protruding bow segment over the sea. In the simulation, an east-west-oriented high wind swath is generated behind the gust front of the MCS. Descending dry rear-to-front inflows behind the bow and trailing gust front are found to feed the downdrafts in the main precipitation regions. The inflows help to establish spreading cold outflows and enhance the downdrafts through evaporative cooling. Meanwhile, front-to-rear inflows from the south are present, associated with severely rearward-tilted updrafts initially forming over the gust front. Such inflows descend behind(north of) the gust front, significantly enhancing downdrafts and near-surface winds within the cold pool. Consistently, calculated trajectories show that these parcels that contribute to the derecho originate primarily from the region ahead(south) of the east-west-oriented gust front, and dry southwesterly flows in the low-to-middle levels contribute to strong downdrafts within the MCS. Moreover, momentum budget analyses reveal that a large westward-directed horizontal pressure gradient force within the simulated cold pool produced rapid flow acceleration towards Nantong. The analyses enrich the understanding of damaging wind characteristics over coastal East China and will prove helpful to operational forecasters.
基金Eleventh Five Year Plan for National Science and Technology Major Project(Grant No.2009ZX0930010)
文摘Compound SLXM-2, a derivative of cyclophosphamide （CTX）, has shown potent growth-inhibitory effect on tumor cells with low toxicity in previous studies. However, the mechanism of its anti-tumor effect, especially on DNA damage, remains largely unclear. This study investigated the effect of SLXM-2 on the survival time of mice transplanted with the ascitie fluid-type hepatocarcinoma 22 （H22）. We also evaluated the correlation between DNA damaging effect of SLXM-2 and its anti-tumor effect, and to probe the possible molecular mechanism for its effect on H22 cells. The results suggested that SLXM-2 significantly （P〈0.05） prolonged the survival time of mice bearing the ascitic fluid-type H22. Furthermore, SLXM-2 induced DNA damage in a dose-dependent manner in H22 cells. Further investigation revealed that SLXM-2 significantly （P〈0.05） up-regulated the expression levels of a series of DNA damage-related proteins, such as γH2AX （Ser139）, p-Chkl （Ser296）, p-Chk2 （Thr68）, p-p53 （Ser15）, p-p53 （Ser20） and p21, and down-regulated the expression of p-ATR （Ser428） and p-ATM （Ser1981）. In conclusion, SLXM-2 showed a remarkable anti-tumor activity on ascitic fluid-type H22 cells, and its molecular mechanism is related to its DNA damaging effect.
文摘Urban trees are subjected to different damaging agents throughout their lifetime. The aims of this study were to identify tree damaging agents, and to obtain a Damage Severity Index (DSI) in order to categorize tree health condition at San Juan de Aragon Park. Each tree was identified at species level in 28 randomly established plots in ten sections of the study area. Up to two types of damage were recorded per tree, based on the FIA (Forest Inventory an Analysis Program) protocol, and a DSI was obtained for each damaged tree considering location of damage, nature of the damaging agent and severity. A total of 753 trees were assessed and 12 species and 27 damaging agents were identified. Cankers, galls, the pepper tree psyllid and the red gum lerp psyllid were the most frequent damaging agents. Australian pine, red gum, Mediterranean cypress, Mexican white cedar, and California pepper were the most affected species. The DSI ranged from 3 to 17 and the average was 7.9. Sections J and H and the species California pepper, Australian pine, and Mexican white cedar presented the highest DSI. The tree population had a moderate health condition, while the aforementioned sections and tree species showed the poorest.
基金supported by the National Natural Science Foundation of China (grant numbers 32100131 and 31670716)Wuhan Science and Technology Bureau[grant numbers 2020020601012318]+1 种基金Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine) (grant numbers WDCM2022008)Jianghan University (grant numbers 08190006,06210035,2021yb138 and 2019037).
文摘Autophagy plays an important role in the interaction between viruses and host cells.SARS-CoV-2 infection can disrupt the autophagy process in target cells.However,the precise molecular mechanism is still unknown.In this study,we discovered that the Nsp8 of SARS-CoV-2 could cause an increasing accumulation of autophagosomes by preventing the fusion of autophagosomes and lysosomes.From further investigation,we found that Nsp8 was present on mitochondria and can damage mitochondria to initiate mitophagy.The results of experiments with immunofluorescence revealed that Nsp8 induced incomplete mitophagy.Moreover,both domains of Nsp8 orchestrated their function during Nsp8-induced mitophagy,in which the N-terminal domain colocalized with mitochondria and the C-terminal domain induced auto/mitophagy.This novel finding expands our understanding of the function of Nsp8 in promoting mitochondrial damage and inducing incomplete mitophagy,which helps us to understand the etiology of COVID-19 as well as open up new pathways for creating SARS-CoV-2 treatment methods.
基金supported by the National Natural Science Foundation of China (No. 20707034, 20877091,20890112, 20921063)the National Basic Research Program (973) of China (No. 09CB421605,2010CB933500, 2011CB936001)
文摘An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation of DNA damaging chemicals. The chemicals that may cause substantial DNA damage will trigger SOS response in the constructed bacterial biosensor, and then the reporter egfp gene under the control of recA promoter is stimulated to express as a fluorescent protein, allowing fast and sensitive fluorescence detection. Interestingly, this biosensor can be simultaneously applied for evaluation of genotoxicity and cytotoxicity. The SOS-EGFP bacterial biosensor provides a sensitive, specific and simple method for detecting known and potential DNA damaging chemicals.
基金Project(07JCZDJC09800) supported by Tianjin Natural Science FoundationProject(50508021) supported by the National Natural Science Foundation of China
文摘An improved damaging model formulated within the framework of bounding surface for structured clays was proposed. The model was intended to describe the effects of structure degradation due to geotechnical loading. The predictive capability of the model was compared with those of triaxial compression test on Tianjin soft clays. The results show that, by incorporating a new damage function into the model, the reduction of elastic bulk and shear modulus with elastic deformations and the reduction of plastic bulk modulus and shear modulus with plastic deformations are able to be appreciable. Before the axial strain reaches 15%, the axial strain computed from the model is smaller than that from the test under the drained condition. Under the undrained condition, after the axial strain reaches 1%, the axial strain increases quickly because of the complete loss of structure and stiffness; and the result computed from the model is nearly equal to that from the model without the incorporation of the damage function due to less plastic strain under undrained condition test.
基金supported by National Natural Science Foundation of China.(No,30100134)
文摘The mutant effects of a keV range nitrogen ion （N＋） beam on enzyme-producing probiotics were studied, particularly with regard to the induction in the genome. The electron spin resonance （ESR） results showed that the signal of ESR spectrum existed in both implanted and non-implanted spores, and the yields of free radicals increased in a dose-dependent manner. The ionic etching and dilapidation of cell wall could be observed distinctly through the scanning electron microscope （SEM）. The mutagenic effect on genome indicated that N＋ implantation could make base mutation. This study provided an insight into the roles low-energy ions might play in inducing mutagenesis of micro-organisms.
文摘The study is to assess the present serviceability rating of Nigerian highways and <span style="font-family:;" "=""><span style="font-family:Verdana;">the load damage effects of overloaded trucks. The researchers used the American</span><span> </span><span style="font-family:Verdana;">Association of State Highway and Transportation Officials (AASHTO) methods. In this study, the highway section of Lokoja-Abuja, Ilorin-Jebba and Abakiliki-Ogoja via Mbok roads were selected, and data were collected through an axle-load survey, automatic traffic count and from secondary sources. The rate of gross vehicle weight violation was found, ranging from 20% to 94% of the axle load distribution across the studied network. Comparing the overloaded vehicle damage factor (V.D.F.) and standard V.D.F., the range was from 1.2 to 41.34 times across the road networks studied, and this explained why the pavement structures of Nigerian roads tend to deteri</span><span><span style="font-family:Verdana;">orate during its service life rapidly. Present serviceability rating was estimated at 3.45, 4.41 and 3.35 for Lokoja-Abuja, Ilorin-Jebba and Abakiliki-Ogoja roads respectively, showing depletion from their initial conditions. The damaging effects of the HGV are less severe at Lokoja-Abuja Road (with </span><i><span style="font-family:Verdana;">g</span></i><span style="font-family:Verdana;"> = 0.30), followed by </span><span><span style="font-family:Verdana;">Ilorin-Jebba Road (with </span><i><span style="font-family:Verdana;">g</span></i><span style="font-family:Verdana;"> = 0.35) and more in Abakiliki-Ogoja Road (with </span><i><span style="font-family:Verdana;">g</span></i><span style="font-family:Verdana;"> = 0.43). The heaviest overload of 94% of the 6-axle vehicles plying at the Lokoja-Abuja road could explain this intense damaging effect on the road pavement</span></span></span></span>
文摘This study investigated the economic impact of tornadoes and damaging winds on county-level income growth in the United States from 1969 to 2023.Using a fi xed eff ect regression methodology,the analysis showed that an average damaging storm and an average tornado reduced income growth in the aff ected counties by 0.16–0.23%and 0.21–0.23%,respectively,translating into a one-time growth loss of approximately USD 5.6 million and USD 6.3 million.The fi ndings also indicate that tornadoes have a 20%greater economic impact than damaging winds.This study underscored the unique challenges posed by tornadoes and damaging winds,which are characterized by their unpredictable nature and concentrated but extreme damage.
基金supported by the 8th AstraZeneca-KHIDI(Korea Health Industry Development Institute)oncology research programa research grant was supported by AstraZeneca and by Grant No.02-2022-0020 from the Seoul National University Hospital(SNUBH)Research Fund.
文摘Objectives:SLFN11(Schlafen-11)enhances sensitivity to DNA-damaging agents(DDAs)and DNA damage response(DDR)inhibitors in various cancer types.However,its function in pancreatic cancer(PC)remains largely unknown.This research aims to investigate the expression patterns of SLFN11 and other SLFN family members in PC and their correlation with drug sensitivity.Methods:SLFN11 expression and genetic alterations were analyzed using publicly available datasets(TCGA and GTEx).Functional studies,including cell cycle,apoptosis assays,and proliferation assays,were performed in SLFN11-knockdown and SLFN11-knockout(KO)PC cells.The relationship between SLFN11 expression and drug responsiveness was assessed via the CellMiner Cross-Database.Results:Analysis of multiple public datasets demonstrated that elevated SLFN11 expression is significantly linked with poor survival outcomes in PC,supporting its function as a predictive marker.Functional assays in PC cell lines demonstrated that SLFN11 knockdown disrupted G1 phase progression and increased apoptosis,indicating its involvement in tumor cell survival.Moreover,while elevated SLFN11 expression correlated with improved sensitivity to gemcitabine in some cell lines,CRISPR/Cas9-mediated SLFN11 knockout resulted in notable gemcitabine resistance.Importantly,this resistance was partially reversed when gemcitabine was combined with cisplatin and DDR inhibitors(Poly(ADP-ribose)polymerase(PARP),ataxia telangiectasia and Rad3 related(ATR),and Wee1 inhibitors),suggesting that SLFN11 modulates the reaction to both DNA-damaging agents and DDR-targeted therapies.Conclusion:Our findings indicate that SLFN11 plays a dual role in PC:as a prognostic marker,with high expression linked to poor clinical outcomes,and as a predictor of drug sensitivity,where its presence is associated with increased gemcitabine efficacy.However,the development of chemoresistance upon SLFN11 loss(and its partial reversal by DDR inhibitors)highlights the complexity of its function.These results underscore that SLFN11 expression alone may not fully determine gemcitabine response,and additional factors are likely involved.Further clinical validation is therefore essential to establish SLFN11 as a reliable biomarker for guiding DDR-targeted therapeutic strategies in PC.
基金FEDER Prostem Research Project,No.1510614(Wallonia DG06)the F.R.S.-FNRS Epiforce Project,No.T.0092.21+4 种基金the F.R.S.-FNRS Cell Squeezer Project,No.J.0061.23the F.R.S.-FNRS Optopattern Project,No.U.NO26.22the Interreg MAT(T)ISSE Project,which is financially supported by Interreg France-Wallonie-Vlaanderen(Fonds Européen de Développement Régional,FEDER-ERDF)Programme Wallon d’Investissement Région Wallone pour les instruments d’imagerie(INSTIMAG UMONS#1910169)support from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programme(AdG grant agreement no.834317,Fueling Transport,PI Frédéric Saudou)。
文摘Advanced microsystems in traumatic brain injury research:Traumatic brain injury(TBI)results from a mechanical insult to the brain,leading to neuronal and axonal damage and subsequently causing a secondary injury.Within minutes of TBI,a neuroinflammatory response is triggered,driven by intricate molecular and cellular inflammatory processes.
基金support from the National Natural Science Foundation of China(No.52308316)the Scientific Research Foundation of Weifang University(Grant No.2024BS42)+2 种基金China Postdoctoral Science Foundation(No.2022M721885)the Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province(No.ZJRMG-2022-01)supported by Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(NO.SKLGME023017).
文摘Investigating the combined effects of mining damage and creep damage on slope stability is crucial,as it can comprehensively reveal the non-linear deformation characteristics of rock under their joint influence.This study develops a fractional-order nonlinear creep constitutive model that incorporates the double damage effect and implements a non-linear creep subroutine for soft rock using the threedimensional finite difference method on the FLAC3D platform.Comparative analysis of the theoretical,numerical,and experimental results reveals that the fractional-order constitutive model,which incorporates the double damage effect,accurately reflects the distinct deformation stages of green mudstone during creep failure and effectively captures the non-linear deformation in the accelerated creep phase.The numerical results show a fitting accuracy exceeding 97%with the creep test curves,significantly outperforming the 61%accuracy of traditional creep models.
基金funding support from the National Natural Science Foundation of China(Grant No.52274082)the Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technology(Grant No.JXUSTQJBJ2020003)the Innovation Fund Designated for Graduate Students of Jiangxi Province(Grant No.YC2023-B215).
文摘The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle on the fracture surface roughness plays an important role in estimating the damage degree and stability of deep rock mass.In this paper,the variations of fracture surface roughness of granite after different heating and thermal cycles were investigated using the joint roughness coefficient method(JRC),three-dimensional(3D)roughness parameters,and fractal dimension(D),and the mechanism of damage and deterioration of granite were revealed.The experimental results show an increase in the roughness of the granite fracture surface as temperature and cycle number were incremented.The variations of JRC,height parameter,inclination parameter and area parameter with the temperature conformed to the Boltzmann's functional distribution,while the D decreased linearly as the temperature increased.Besides,the anisotropy index(Ip)of the granite fracture surface increased as the temperature increased,and the larger parameter values of roughness characterization at different temperatures were attained mainly in directions of 20°–40°,60°–100°and 140°–160°.The fracture aperture of granite after fracture followed the Gauss distribution and the average aperture increased with increasing temperature,which increased from 0.665 mm at 25℃to 1.058 mm at 800℃.High temperature caused an uneven thermal expansion,water evaporation,and oxidation of minerals within the granite,which promoted the growth and expansion of microfractures,and reduced interparticle bonding strength.In particular,the damage was exacerbated by the expansion and cracking of the quartz phase transition after T>500℃.Thermal cycles contributed to the accumulation of this damage and further weakened the interparticle bonding forces,resulting in a significant increase in the roughness,anisotropy,and aperture of the fracture surface after five cycles.
基金supported by the National Natural Science Foundation of China(Grant No.12172052)the Foundation of State Key Laboratory of Explosion Science and Safety Protection(Grant No.QKKT24-02).
文摘The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagration coupling damage model is developed to predict the penetration depth and cratering diameter.Four type of aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with densities of 2.3,2.7,3.5,and 4.5 g·cm^(-3) are selected to conduct the penetration experiments.The comparison results show that model predictions are in good agreement with the experimental data.By comparing the penetration depth and cratering diameter in the inert penetration mode and the penetration-deflagration coupling mode,the influence mechanism that the penetration-induced chemical response is unfavorable to penetration but has an enhanced cratering effect is revealed.From the formation characteristics,penetration effect and penetration-induced chemical reaction be-haviors,the influence of reactive liner density on the penetration-deflagration performance is further analyzed.The results show that increasing the density of reactive liner significantly increases both the kinetic energy and length of the reactive penetrator,meanwhile effectively reduces the weakened effect of penetration-induced chemical response,resulting in an enhanced penetration capability.However,due to the decreased diameter and potential energy content of reactive penetrator,the cratering capa-bility is weakened significantly.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U20A20266 and 12302503)Scientific and technological research projects in Sichuan province(Grant No.2024NSFSC0973).
文摘The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ultimate strength.In this study,both the acoustic emission method(AEM)and the ultrasonic testing method(UTM)were used to examine the characteristics of AE parameters(b-value,peak frequency,frequency-band energy ratio,and fractal dimension)and ultrasonic(ULT)properties(velocity,amplitude,energy attenuation,and scattering attenuation)of bedded shale at CI,CD,and ultimate strength.The comparison involved analyzing the strain-based method(SBM),AEM,and UTM to determine the thresholds for damage stress.A fuzzy comprehensive evaluation model(FCEM)was created to describe the damage thresholds and hazard assessment.The results indicate that the optimal AE and ULT parameters for identifying CI and CD stress are ringing count,ultrasonic amplitude,energy attenuation,and scattering attenuation of the S-wave.Besides,damage thresholds were detected earlier by AE monitoring,ranging from 3 MPa to 10 MPa.CI and CD identified by UTM occurred later than SBM and AEM,and were in the range of 12 MPa.The b-value,peak frequency,energy ratio in the low-frequency band(0e62.5 kHz),correlation dimension,and sandbox dimension showed low values at the peak stress,while the energy ratio in a moderate-frequency band(187.5e281.25 kHz)and amplitude showed high values.The successful application of FCEM to laboratory testing of shales has demonstrated its ability to quantitatively identify AE/ULT precursors of seismic hazards associated with rock failure.
基金financially supported by the Beijing Natural Science Foundation,China (No.JQ21028)the National Natural Science Foundation of China (Nos.52311530070,52278326,and 52004015)+2 种基金the Major National Science and Technology Project for Deep Earth,China (No.2024ZD1003805)the Project from PetroChina RIPED:the Study on the evolution law of Mineral Structure and Rock Mechanical Properties Under Ultra-High Temperature Conditions (No.2022-KFKT-02)the Fundamental Research Funds for the Central Universities of China (No.FRF-IDRY-20-003,Interdisciplinary Research Project for Young Teachers of USTB)。
文摘Low-to medium-maturity oil shale resources display substantial reserves, offering promising prospects for in-situ conversion inChina. Investigating the evolution of the mechanical properties of the reservoir and caprock under in-situ high-temperature and confine-ment conditions is of considerable importance. Compared to conventional mechanical experiments on rock samples after high-temperat-ure treatment, in-situ high-temperature experiments can more accurately characterize the behavior of rocks in practical engineering,thereby providing a more realistic reflection of their mechanical properties. In this study, an in-situ high-temperature triaxial compressiontesting machine is developed to conduct in-situ compression tests on sandstone at different temperatures(25, 200, 400, 500, and 650℃)and confining pressures(0, 10, and 20 MPa). Based on the experimental results, the temperature-dependent changes in compressivestrength, peak strain, elastic modulus, Poisson's ratio, cohesion, and internal friction angle are thoroughly analyzed and discussed. Resultsindicate that the mass of sandstone gradually decreases as the temperature increases. The thermal conductivity and thermal diffusivity ofsandstone exhibit a linear relationship with temperature. Peak stress decreases as the temperature rises, while it increases with higher con-fining pressures. Notably, the influence of confining pressure on peak stress diminishes at higher temperatures. Additionally, as the tem-perature rises, the Poisson's ratio of sandstone decreases. The internal friction angle also decreases with increasing temperature, with 400℃ acting as the threshold temperature. Interestingly, under uniaxial conditions, the damage stress of sandstone is less affected by tem-perature. However, when the confining pressure is 10 or 20 MPa, the damage stress decreases as the temperature increases. This study en-hances our understanding of the influence of in-situ high-temperature and confinement conditions on the mechanical properties of sand-stone strata. The study also provides valuable references and experimental data that support the development of low-to medium-maturityoil shale resources.
基金support by the National Natural Science Foundation of China(52201077)the Natural Science Foundation of Shandong Province(ZR2022QE191)+1 种基金Elite Scheme of Shandong University of Science and Technology(0104060541123)Talent introduction and Research Start-up Fund of Shandong University of Science and Technology(0104060510124).
文摘Coating microdefects and localized corrosion in coating/metal system are inevitable,accelerating the degradation of metal infrastructure.Early evaluating coating microdefects and detecting corrosion sites are urgent yet remain challenge to achieve.Herein,we propose a robust,universal and efficient fluorescence-based strategy for hierarchical warning of coating damage and metal corrosion by introducing the concepts of damage-induced fluorescence enhancement effect(DIE)and ionic-recognition induced quenching effect(RIQ).The coatings with dualresponsiveness for coating defect and steel corrosion are constructed by incorporating synthesized nanoprobes composed of metal organic frameworks(Ni–Zn-MOFs)loaded with Rhodamine B(RhB@MOFs).The initial damage to the coating causes an immediate intensification of fluorescence,while the specific ionic-recognition characteristic of RhB with Fe3t results in an evident fluorescence quenching,enabling the detection of coating damage and corrosion.Importantly,this nanoprobes are insensitive to the coating matrix and exhibit stable corrosion warning capability across various coating systems.Meanwhile,electrochemical investigations indicate that the impedance values of RM/EP maintain above 10^(8)Ωcm^(2)even after 60 days of immersion.Therefore,the incorporation of fluorescent nanoprobes greatly inhibits the intrusion of electrolytes into polymer and improves the corrosion protection performance of the coating.This powerful strategy towards dual-level damage warning provides insights for the development of long-term smart protective materials.
基金supported by the National Natural Science Foundation of China(Nos.82241088 and 82203996)the China Postdoctoral Science Foundation(Nos.2022T150230 and 2021M691131).
文摘Arsenic-related oxidative stress and resultant diseases have attracted global concern,while longitudinal studies are scarce.To assess the relationship between arsenic exposure and systemic oxidative damage,we performed two repeatedmeasures among 5236 observations(4067 participants)in theWuhan-Zhuhai cohort at the baseline and follow-up after 3 years.Urinary total arsenic,biomarkers of DNA oxidative damage(8-hydroxy-2-deoxyguanosine(8-OHdG)),lipid peroxidation(8-isoprostaglandin F2alpha(8-isoPGF2α)),and protein oxidative damage(protein carbonyls(PCO))were detected for all observations.Here we used linearmixed models to estimate the cross-sectional and longitudinal associations between arsenic exposure and oxidative damage.Exposure-response curves were constructed by utilizing the generalized additive mixed models with thin plate regressions.After adjusting for potential confounders,arsenic level was significantly and positively related to the levels of global oxidative damage and their annual increased rates in dose-response manners.In cross-sectional analyses,each 1%increase in arsenic levelwas associated with a 0.406%(95%confidence interval(CI):0.379%to 0.433%),0.360%(0.301%to 0.420%),and 0.079%(0.055%to 0.103%)increase in 8-isoPGF2α,8-OHdG,and PCO,respectively.More importantly,arsenic was further found to be associated with increased annual change rates of 8-isoPGF2α(β:0.147;95%CI:0.130 to 0.164),8-OHdG(0.155;0.118 to 0.192),and PCO(0.050;0.035 to 0.064)in the longitudinal analyses.Our study suggested that arsenic exposurewas not only positively related with global oxidative damage to lipid,DNA,and protein in cross-sectional analyses,but also associated with annual increased rates of these biomarkers in dose-dependent manners.
