A hard problem that hinders the movement of waxy crude oil is wax deposition in oil pipelines.To ensure the safe operation of crude oil pipelines,an accurate model must be developed to predict the rate of wax depositi...A hard problem that hinders the movement of waxy crude oil is wax deposition in oil pipelines.To ensure the safe operation of crude oil pipelines,an accurate model must be developed to predict the rate of wax deposition in crude oil pipelines.Aiming at the shortcomings of the ENN prediction model,which easily falls into the local minimum value and weak generalization ability in the implementation process,an optimized ENN prediction model based on the IRSA is proposed.The validity of the new model was confirmed by the accurate prediction of two sets of experimental data on wax deposition in crude oil pipelines.The two groups of crude oil wax deposition rate case prediction results showed that the average absolute percentage errors of IRSA-ENN prediction models is 0.5476% and 0.7831%,respectively.Additionally,it shows a higher prediction accuracy compared to the ENN prediction model.In fact,the new model established by using the IRSA to optimize ENN can optimize the initial weights and thresholds in the prediction process,which can overcome the shortcomings of the ENN prediction model,such as weak generalization ability and tendency to fall into the local minimum value,so that it has the advantages of strong implementation and high prediction accuracy.展开更多
Low-temperature,ambient processing of high-quality CsPbBr_(3)films is demanded for scalable production of efficient,low-cost carbon-electrode perovskite solar cells(PSCs).Herein,we demonstrate a crystal orientation en...Low-temperature,ambient processing of high-quality CsPbBr_(3)films is demanded for scalable production of efficient,low-cost carbon-electrode perovskite solar cells(PSCs).Herein,we demonstrate a crystal orientation engineering strategy of PbBr_(2)precursor film to accelerate its reaction with CsBr precursor during two-step sequential deposition of CsPbBr_(3)films.Such a novel strategy is proceeded by adding CsBr species into PbBr_(2)precursor,which can tailor the preferred crystal orientation of PbBr_(2)film from[020]into[031],with CsBr additive staying in the film as CsPb_(2)Br_(5)phase.Theoretical calculations show that the reaction energy barrier of(031)planes of PbBr_(2)with CsBr is lower about 2.28 eV than that of(O2O)planes.Therefore,CsPbBr_(3)films with full coverage,high purity,high crystallinity,micro-sized grains can be obtained at a low temperature of 150℃.Carbon-electrode PSCs with these desired CsPbBr_(3)films yield the record-high efficiency of 10.27%coupled with excellent operation stability.Meanwhile,the 1 cm^(2)area one with the superior efficiency of 8.00%as well as the flexible one with the champion efficiency of 8.27%and excellent mechanical bending characteristics are also achieved.展开更多
Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent N...Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.展开更多
Objective:To investigate the effects of acupotomy on skeletal muscle fibrosis and collagen deposition in a rabbit knee osteoarthritis(KOA)model.Methods: Rabbits(n=18)were randomly divided into control,KOA,and KOA+acup...Objective:To investigate the effects of acupotomy on skeletal muscle fibrosis and collagen deposition in a rabbit knee osteoarthritis(KOA)model.Methods: Rabbits(n=18)were randomly divided into control,KOA,and KOA+acupotomy(Apo)groups(n=6).The rabbits in the KOA and Apo groups were modeled using the modified Videman's method for 6 weeks.After modeling,the Apo group was subjected to acupotomy once a week for 3 weeks on the vastus medialis,vastus lateralis,rectus femoris,biceps femoris,and anserine bursa tendons around the knee.The behavior of all animals was recorded,rectus femoris tissue was obtained,and histomorphological changes were observed using Masson staining and transmission electron microscopy.The expression of transforming growth factor-β1(TGF-β1),Smad 3,Smad 7,fibrillar collagen types I(Col-I)and III(Col-III)was detected using Western blot and real-time polymerase chain reaction(RT-PCR).Results: Histological analysis revealed that acupotomy improved the microstructure and reduced the collagen volume fraction of rectus femoris,compared with the KOA group(P=.034).Acupotomy inhibited abnormal collagen deposition by modulating the expression of fibrosis-related proteins and mRNA,thus preventing skeletal muscle fibrosis.Western blot and RT-PCR analysis revealed that in the Apo group,Col-I,and Col-III protein levels were significantly lower than those in the KOA group(both P<.01),same as Col-I and Col-III mRNA levels(P=.0031;P=.0046).Compared with the KOA group,the protein levels of TGF-β1 and Smad 3 were significantly reduced(both P<.01),as were the mRNA levels of TGF-β1 and Smad 3(P=.0007;P=.0011).Conversely,the levels of protein and mRNA of Smad 7 were significantly higher than that in the KOA group(P<.01;P=.0271).Conclusion: Acupotomy could alleviate skeletal muscle fibrosis and delay KOA progress by inhibiting collagen deposition through the TGF-β/Smad pathway in the skeletal muscle of KOA rabbits.展开更多
The effect of deposition temperature on the morphology and optoelectronic performance of Ge/Si QDs grown by magnetron sputtering under low Ge deposition(~4 nm)was investigated by atomic force microscopy,Raman spectros...The effect of deposition temperature on the morphology and optoelectronic performance of Ge/Si QDs grown by magnetron sputtering under low Ge deposition(~4 nm)was investigated by atomic force microscopy,Raman spectroscopy,and photoluminescence(PL)tests.The experimental results indicate that temperatures higher than 750℃effectively increase the crystallization rate and surface smoothness of the Si buffer layer,and temperatures higher than 600℃significantly enhance the migration ability of Ge atoms,thus increasing the probability of Ge atoms meeting and nucleating to form QDs on Si buffer layer,but an excessively high temperature will cause the QDs to undergo an Ostwald ripening process and thus develop into super large islands.In addition,some PL peaks were observed in samples containing small-sized,high-density Ge QDs,the photoelectric properties reflected by these peaks were in good agreement with the corresponding structural characteristics of the grown QDs.Our results demonstrate the viability of preparing high-quality QDs by magnetron sputtering at high deposition rate,and the temperature effect is expected to work in conjunction with other controllable factors to further regulate QD growth,which paves an effective way for the industrial production of QDs that can be used in future devices.展开更多
Objective:Diabetic nephropathy(DN)is a deleterious microangiopathy of diabetes,constituting a critical determinant of fatality in diabetic patients.This work is purposed to disclose the effects and modulatory mechanis...Objective:Diabetic nephropathy(DN)is a deleterious microangiopathy of diabetes,constituting a critical determinant of fatality in diabetic patients.This work is purposed to disclose the effects and modulatory mechanism of BTG anti-proliferation factor 2(BTG2)during the pathological process of DN.Methods:BTG2 expression in kidney tissues of diabetic mice and high glucose(HG)-exposed human proximal tubular cell line HK-2 was assessed with Western blot and RT-qPCR.The diabetic mice model was constructed by streptozotocin injection and confirmed by the blood glucose level beyond 16.7 mmol/L.Hematoxylin and eosin(H&E)staining and measurement of kidney function hallmarks were conducted to assess kidney injury.Cell counting kit(CCK)-8 method and TUNEL assay appraised cell activity and apoptosis.Oil red O staining assayed lipid accumulation.Relevant commercial kits were used to estimate oxidative stress-related factors.Co-immunoprecipitation(Co-IP)assay testified the binding relationship of BTG2 with protein arginine methyltransferase 1(PRMT1).Results:BTG2 expression was significantly raised in renal tissues of diabetic mice and HK-2 cells exposed to HG.BTG2 deficiency improved viability and extenuated the apoptosis,lipid deposition as well as oxidative stress in HK-2 cells following HG exposure.In addition,PRMT1 was also overexpressed in HK-2 cells exposed to HG.BTG2 interacted with PRMT1 and positively modulated PRMT1 expression.The effects of BTG2 interference on viability,apoptosis,lipid deposition,and oxidative stress in HG-challenged HK-2 cells were partially abrogated by PRMT1 overexpression.Conclusion:Altogether,BTG2 might aggravate HK-2 cell injury in response to HG by binding with PRMT1,providing a novel target for the therapeutic strategy of DN.展开更多
Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function...Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function and whole-plant level C cycling.CO_(2)elevation and nitrogen(N)deposition,which are two major environmental issues worldwide,aff ect plant photosynthetic C assimilation and C release in forest ecosystems.However,information regarding the eff ect of CO_(2)elevation and N deposition on NSC storage in diff erent organs remains limited,especially regarding the trade-off between growth and NSC reserves.Therefore,here we analyzed the variations in the NSC storage in diff erent organs of Chinese fi r(Cunninghamia lanceolata)under CO_(2)elevation and N addition and found that NSC concentrations and contents in all organs of Chinese fi r saplings increased remarkably under CO_(2)elevation.However,N addition induced diff erential accumulation of NSC among various organs.Specifi cally,N addition decreased the NSC concentrations of needles,branches,stems,and fi ne roots,but increased the NSC contents of branches and coarse roots.The increase in the NSC contents of roots was more pronounced than that in the NSC content of aboveground organs under CO_(2)elevation.The role of N addition in the increase in the structural biomass of aboveground organs was greater than that in the increase in the structural biomass of roots.This result indicated that a diff erent tradeoff between growth and NSC storage occurred to alleviate resource limitations under CO_(2)elevation and N addition and highlights the importance of separating biomass into structural biomass and NSC reserves when investigating the eff ects of environmental change on biomass allocation.展开更多
The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pre...The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pressure chemical vapor deposition(APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO_(2) grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl_(4) concentration increased from 0.38%to 2.44%. The grain size increased with the TiCl_(4) concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO_(2) clusters at the initial stage finally result to the agglomeration of fine TiO_(2) grains at high TiCl_(4) concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl_(4) concentration is below 0.90%.展开更多
Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aero...Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport industries.However,their widespread application is hindered by their low formability at room temperature due to limited slip systems.Cast Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high scrap.While casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain applications.Although metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast counterparts.Thus,MAM is a promising technique to produce Mg alloy parts.Directed energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive processes.However,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this technology.This review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and prospects.Furthermore,the predominant imperfections,notably inhomogeneous microstructure evolution and porosity,observed in Mg-alloy components manufactured through DED are discussed.Additionally,the preventive measures implemented to counteract the formation of these defects are explored.展开更多
This work constructed a machine learning(ML)model to predict the atmospheric corrosion rate of low-alloy steels(LAS).The material properties of LAS,environmental factors,and exposure time were used as the input,while ...This work constructed a machine learning(ML)model to predict the atmospheric corrosion rate of low-alloy steels(LAS).The material properties of LAS,environmental factors,and exposure time were used as the input,while the corrosion rate as the output.6 dif-ferent ML algorithms were used to construct the proposed model.Through optimization and filtering,the eXtreme gradient boosting(XG-Boost)model exhibited good corrosion rate prediction accuracy.The features of material properties were then transformed into atomic and physical features using the proposed property transformation approach,and the dominant descriptors that affected the corrosion rate were filtered using the recursive feature elimination(RFE)as well as XGBoost methods.The established ML models exhibited better predic-tion performance and generalization ability via property transformation descriptors.In addition,the SHapley additive exPlanations(SHAP)method was applied to analyze the relationship between the descriptors and corrosion rate.The results showed that the property transformation model could effectively help with analyzing the corrosion behavior,thereby significantly improving the generalization ability of corrosion rate prediction models.展开更多
Pulse rate is one of the important characteristics of traditional Chinese medicine pulse diagnosis,and it is of great significance for determining the nature of cold and heat in diseases.The prediction of pulse rate b...Pulse rate is one of the important characteristics of traditional Chinese medicine pulse diagnosis,and it is of great significance for determining the nature of cold and heat in diseases.The prediction of pulse rate based on facial video is an exciting research field for getting palpation information by observation diagnosis.However,most studies focus on optimizing the algorithm based on a small sample of participants without systematically investigating multiple influencing factors.A total of 209 participants and 2,435 facial videos,based on our self-constructed Multi-Scene Sign Dataset and the public datasets,were used to perform a multi-level and multi-factor comprehensive comparison.The effects of different datasets,blood volume pulse signal extraction algorithms,region of interests,time windows,color spaces,pulse rate calculation methods,and video recording scenes were analyzed.Furthermore,we proposed a blood volume pulse signal quality optimization strategy based on the inverse Fourier transform and an improvement strategy for pulse rate estimation based on signal-to-noise ratio threshold sliding.We found that the effects of video estimation of pulse rate in the Multi-Scene Sign Dataset and Pulse Rate Detection Dataset were better than in other datasets.Compared with Fast independent component analysis and Single Channel algorithms,chrominance-based method and plane-orthogonal-to-skin algorithms have a more vital anti-interference ability and higher robustness.The performances of the five-organs fusion area and the full-face area were better than that of single sub-regions,and the fewer motion artifacts and better lighting can improve the precision of pulse rate estimation.展开更多
Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,...Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate limitations.In this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates.To our knowledge,this is the first reported practical dynamic interactive metasurface holographic system.We spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed sub-pattern.The switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame rate.Our approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational platform.According to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram creation.Our technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems.展开更多
Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures;however,the material compatibility and bondability directly affect the parts’formability and final quality...Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures;however,the material compatibility and bondability directly affect the parts’formability and final quality.It is essential to understand the underlying printability of different material combinations based on an adapted process.Here,the printability disparities of two common and attractive material combinations(nickel-and iron-based alloys)are evaluated at the macro and micro levels via laser directed energy deposition(DED).The deposition processes were captured using in situ high-speed imaging,and the dissimilarities in melt pool features and track morphology were quantitatively investigated within specific process windows.Moreover,the microstructure diversity of the tracks and blocks processed with varied material pairs was comparatively elaborated and,complemented with the informative multi-physics modeling,the presented non-uniformity in mechanical properties(microhardness)among the heterogeneous material pairs was rationalized.The differences in melt flow induced by the unlike thermophysical properties of the material pairs and the resulting element intermixing and localized re-alloying during solidification dominate the presented dissimilarity in printability among the material combinations.This work provides an in-depth understanding of the phenomenological differences in the deposition of dissimilar materials and aims to guide more reliable DED forming of bimetallic parts.展开更多
In grain crops such as maize(Zea mays),leaf angle(LA)is a key agronomic trait affecting light interception and thus planting density and yield.Nitrogen(N)affects LA in plants,but we lack a good understanding of how N ...In grain crops such as maize(Zea mays),leaf angle(LA)is a key agronomic trait affecting light interception and thus planting density and yield.Nitrogen(N)affects LA in plants,but we lack a good understanding of how N regulates LA.Here,we report that N deficiency enhanced lignin deposition in the ligular region of maize seedlings.In situ hybridization showed that the bZIP transcription factor gene ZmbZIP27 is mainly expressed in the phloem of maize vascular bundles.Under N-sufficient conditions,transgenic maize overexpressing ZmbZIP27 showed significantly smaller LA compared with wild type(WT).By contrast,zmbzip27_(ems)mutant showed larger LA under both N-deficient and N-sufficient conditions compared with WT.Overexpression of ZmbZIP27 enhanced lignin deposition in the ligular region of maize in the field.We further demonstrated that ZmbZIP27 could directly bind the promoters of the microRNA genes ZmMIR528a and ZmMIR528b and negatively regulate the expression levels of ZmmiR528.ZmmiR528 knockdown transgenic maize displayed erect architecture in the field by increasing lignin content in the ligular region of maize.Taken together,these results indicate that ZmbZIP27 regulates N-mediated LA size by regulating the expression of ZmmiR528 and modulating lignin deposition in maize.展开更多
The process of entrainment-mixing between cumulus clouds and the ambient air is important for the development of cumulus clouds.Accurately obtaining the entrainment rate(λ)is particularly important for its parameteri...The process of entrainment-mixing between cumulus clouds and the ambient air is important for the development of cumulus clouds.Accurately obtaining the entrainment rate(λ)is particularly important for its parameterization within the overall cumulus parameterization scheme.In this study,an improved bulk-plume method is proposed by solving the equations of two conserved variables simultaneously to calculateλof cumulus clouds in a large-eddy simulation.The results demonstrate that the improved bulk-plume method is more reliable than the traditional bulk-plume method,becauseλ,as calculated from the improved method,falls within the range ofλvalues obtained from the traditional method using different conserved variables.The probability density functions ofλfor all data,different times,and different heights can be well-fitted by a log-normal distribution,which supports the assumed stochastic entrainment process in previous studies.Further analysis demonstrate that the relationship betweenλand the vertical velocity is better than other thermodynamic/dynamical properties;thus,the vertical velocity is recommended as the primary influencing factor for the parameterization ofλin the future.The results of this study enhance the theoretical understanding ofλand its influencing factors and shed new light on the development ofλparameterization.展开更多
Rockburst are often encountered in tunnel construction due to the complex geological conditions.To study the influence of unloading rate on rockburst,gneiss rockburst experiments were conducted under three groups of u...Rockburst are often encountered in tunnel construction due to the complex geological conditions.To study the influence of unloading rate on rockburst,gneiss rockburst experiments were conducted under three groups of unloading rates.A high-speed photography system and acoustic emission(AE)system were used to monitor the entire process of rockburst process in real-time.The results show that the intensity of gneiss rockburst decreases with decrease of unloading rate,which is manifested as the reduction of AE energy and fragments ejection velocity.The mechanisms are proposed to explain this effect:(i)The reduction of unloading rate changes the crack propagation mechanism in the process of rockburst.This makes the rockbursts change from the tensile failure mechanism at high unloading rate to the tension-shear mixed failure mechanism at low unloading rate,and more energy released in the form of shear crack propagation.Then,less strain energy is converted into kinetic energy of fragments ejection.(ii)Less plate cracking degree of gneiss has taken shape due to decrease of unloading rate,resulting in the destruction of rockburst incubation process.The enlightenments of reducing the unloading rate for the project are also described quantitatively.The rockburst magnitude is reduced from the medium magnitude at the unloading rate of 0.1 MPa/s to the slight magnitude at the unloading rate of 0.025 MPa/s,which was judged by the ejection velocity.展开更多
The mutation rate is a pivotal biological characteristic,intricately governed by natural selection and historically garnering considerable attention.Recent advances in high-throughput sequencing and analytical methodo...The mutation rate is a pivotal biological characteristic,intricately governed by natural selection and historically garnering considerable attention.Recent advances in high-throughput sequencing and analytical methodologies have profoundly transformed our understanding in this domain,ushering in an unprecedented era of mutation rate research.This paper aims to provide a comprehensive overview of the key concepts and methodologies frequently employed in the study of mutation rates.It examines various types of mutations,explores the evolutionary dynamics and associated theories,and synthesizes both classical and contemporary hypotheses.Furthermore,this review comprehensively explores recent advances in understanding germline and somatic mutations in animals and offers an overview of experimental methodologies,mutational patterns,molecular mechanisms,and driving forces influencing variations in mutation rates across species and tissues.Finally,it proposes several potential research directions and pressing questions for future investigations.展开更多
The Earth’s surface kinematics and deformation are fundamental to understanding crustal evolution.An effective research approach is to estimate regional motion field and deformation fields based on modern geodetic ne...The Earth’s surface kinematics and deformation are fundamental to understanding crustal evolution.An effective research approach is to estimate regional motion field and deformation fields based on modern geodetic networks.If the discrete observed velocity field is obtained,the velocity related fields,such as dilatation rate and maximum shear strain rate,can be estimated by applying varied mathematical approaches.This study applied Akaike's Bayesian Information Criterion(ABIC)method to calculate strain rate fields constrained by GPS observations in the southeast Tibetan Plateau.Comparison with results derived from other three methods revealed that our ABIC-derived strain rate fields were more precise.The maximum shear strain rate highlighted the Xianshuihe–Xiaojiang fault system as the main boundary for the outward migration of material in southeastern Tibet,indicating rotation of eastern Tibet material around the eastern Himalaya rather than whole extrusion along a fixed channel.Additionally,distinct dilatation rate patterns in the northeast and southwest regions of the fault system were observed.The northeast region,represented by the Longmenshan area,exhibited negative dilatational anomalies;while the southwest region,represented by the Jinsha River area north of 29°N,displayed positive dilatational anomalies.This indicates compression in the former and extension in the latter.Combined with deep geophysical observations,we believe that the upper and lower crusts of the Jinsha River area north of 29°N are in an entire expanding state,probably caused by the escape-drag effect of material.The presence of a large,low-viscosity region south of 29°N may not enable the entire escape of the crust,but instead result in a differential escape of the lower crust faster than the upper crust.展开更多
Background Adequate level of carbohydrates in aquafeeds help to conserve protein and reduce cost. However, studies have indicated that high-carbohydrate(HC) diet disrupt the homeostasis of the gut–liver axis in large...Background Adequate level of carbohydrates in aquafeeds help to conserve protein and reduce cost. However, studies have indicated that high-carbohydrate(HC) diet disrupt the homeostasis of the gut–liver axis in largemouth bass, resulting in decreased intestinal acetate and butyrate level.Method Herein, we had concepted a set of feeding experiment to assess the effects of dietary sodium acetate(SA) and sodium butyrate(SB) on liver health and the intestinal microbiota in largemouth bass fed an HC diet. The experimental design comprised 5 isonitrogenous and isolipidic diets, including LC(9% starch), HC(18% starch), HCSA(18% starch;2 g/kg SA), HCSB(18% starch;2 g/kg SB), and HCSASB(18% starch;1 g/kg SA + 1 g/kg SB). Juvenile largemouth bass with an initial body weight of 7.00 ± 0.20 g were fed on these diets for 56 d.Results We found that dietary SA and SB reduced hepatic triglyceride accumulation by activating autophagy(ATG101, LC3B and TFEB), promoting lipolysis(CPT1α, HSL and AMPKα), and inhibiting adipogenesis(FAS, ACCA, SCD1 and PPARγ). In addition, SA and SB decreased oxidative stress in the liver(CAT, GPX1α and SOD1) by activating the Keap1-Nrf2 pathway. Meanwhile, SA and SB alleviated HC-induced inflammation by downregulating the expression of pro-inflammatory factors(IL-1β, COX2 and Hepcidin1) through the NF-κB pathway. Importantly, SA and SB increased the abundance of bacteria that produced acetic acid and butyrate(Clostridium_sensu_stricto_1). Combined with the KEGG analysis, the results showed that SA and SB enriched carbohydrate metabolism and amino acid metabolism pathways, thereby improving the utilization of carbohydrates. Pearson correlation analysis indicated that growth performance was closely related to hepatic lipid deposition, autophagy, antioxidant capacity, inflammation, and intestinal microbial composition.Conclusions In conclusion, dietary SA and SB can reduce hepatic lipid deposition;and alleviate oxidative stress and inflammation in largemouth bass fed on HC diet. These beneficial effects may be due to the altered composition of the gut microbiota caused by SA and SB. The improvement effects of SB were stronger than those associated with SA.展开更多
Warming and nitrogen(N)deposition are two important drivers of global climate changes.Coarse woody debris(CWD)contains a large proportion of the carbon(C)in the total global C pool.The composition of soil microbial co...Warming and nitrogen(N)deposition are two important drivers of global climate changes.Coarse woody debris(CWD)contains a large proportion of the carbon(C)in the total global C pool.The composition of soil microbial communities and environmental changes(i.e.,N deposition and warming)are the key drivers of CWD decomposition,but the interactive impact between N deposition and warming on the composition of soil microbial communities and CWD decomposition is still unclear.In a laboratory experiment,we study and simulate respiration during decomposition of the CWD(C 98)of Cryptomeria japonica(CR)and Platycarya strobilacea(PL)in response to warming and N deposition over 98 days.Resuts show that either warming or N addition signifi cantly accelerated the C 98 of the two tree species by altering the soil microbial community(bacterial:fungi and G+:G–).The combined treatment(warming+N)resulted in a decomposition eff ect equal to the sum of the individual eff ects.In addition,the species composition of bacteria and fungi was obviously aff ected by warming.However,N deposition had a remarkable infl uence on G+:G–.Our results indicated that N deposition and warming will observably alter the composition and growth of the microbial community and thus work synergistically to accelerate CWD decomposition in forest ecosystems.We also present evidence that N deposition and warming infl uenced the composition and balance of soil microbial communities and biogeochemical cycling of forest ecosystems.展开更多
文摘A hard problem that hinders the movement of waxy crude oil is wax deposition in oil pipelines.To ensure the safe operation of crude oil pipelines,an accurate model must be developed to predict the rate of wax deposition in crude oil pipelines.Aiming at the shortcomings of the ENN prediction model,which easily falls into the local minimum value and weak generalization ability in the implementation process,an optimized ENN prediction model based on the IRSA is proposed.The validity of the new model was confirmed by the accurate prediction of two sets of experimental data on wax deposition in crude oil pipelines.The two groups of crude oil wax deposition rate case prediction results showed that the average absolute percentage errors of IRSA-ENN prediction models is 0.5476% and 0.7831%,respectively.Additionally,it shows a higher prediction accuracy compared to the ENN prediction model.In fact,the new model established by using the IRSA to optimize ENN can optimize the initial weights and thresholds in the prediction process,which can overcome the shortcomings of the ENN prediction model,such as weak generalization ability and tendency to fall into the local minimum value,so that it has the advantages of strong implementation and high prediction accuracy.
基金the financial support from the National Key R&D program of China(2021YFF0500501 and 2021YFF0500504)the Fundamental Research Funds for the Central Universities(YJS2213 and JB211408)+1 种基金the National Natural Science Foundation of China(61874083)the Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University(No.2020GXLH-Z-014)
文摘Low-temperature,ambient processing of high-quality CsPbBr_(3)films is demanded for scalable production of efficient,low-cost carbon-electrode perovskite solar cells(PSCs).Herein,we demonstrate a crystal orientation engineering strategy of PbBr_(2)precursor film to accelerate its reaction with CsBr precursor during two-step sequential deposition of CsPbBr_(3)films.Such a novel strategy is proceeded by adding CsBr species into PbBr_(2)precursor,which can tailor the preferred crystal orientation of PbBr_(2)film from[020]into[031],with CsBr additive staying in the film as CsPb_(2)Br_(5)phase.Theoretical calculations show that the reaction energy barrier of(031)planes of PbBr_(2)with CsBr is lower about 2.28 eV than that of(O2O)planes.Therefore,CsPbBr_(3)films with full coverage,high purity,high crystallinity,micro-sized grains can be obtained at a low temperature of 150℃.Carbon-electrode PSCs with these desired CsPbBr_(3)films yield the record-high efficiency of 10.27%coupled with excellent operation stability.Meanwhile,the 1 cm^(2)area one with the superior efficiency of 8.00%as well as the flexible one with the champion efficiency of 8.27%and excellent mechanical bending characteristics are also achieved.
基金This work was supported by the National Natural Science Foundation of China(51874332,51991363)the CNPC's Major Science and Technology Projects(ZD2019-184-003)+1 种基金the Fundamental Research Funds for Central Universities(20CX05008A)“14th Five-Year plan”forward-looking basic major science and technology project of CNPC(2021DJ4901).
文摘Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.
基金supported by the National Natural Science Foundation of China(82074523)the National Natural Youth Science Foundation of China(82004448).
文摘Objective:To investigate the effects of acupotomy on skeletal muscle fibrosis and collagen deposition in a rabbit knee osteoarthritis(KOA)model.Methods: Rabbits(n=18)were randomly divided into control,KOA,and KOA+acupotomy(Apo)groups(n=6).The rabbits in the KOA and Apo groups were modeled using the modified Videman's method for 6 weeks.After modeling,the Apo group was subjected to acupotomy once a week for 3 weeks on the vastus medialis,vastus lateralis,rectus femoris,biceps femoris,and anserine bursa tendons around the knee.The behavior of all animals was recorded,rectus femoris tissue was obtained,and histomorphological changes were observed using Masson staining and transmission electron microscopy.The expression of transforming growth factor-β1(TGF-β1),Smad 3,Smad 7,fibrillar collagen types I(Col-I)and III(Col-III)was detected using Western blot and real-time polymerase chain reaction(RT-PCR).Results: Histological analysis revealed that acupotomy improved the microstructure and reduced the collagen volume fraction of rectus femoris,compared with the KOA group(P=.034).Acupotomy inhibited abnormal collagen deposition by modulating the expression of fibrosis-related proteins and mRNA,thus preventing skeletal muscle fibrosis.Western blot and RT-PCR analysis revealed that in the Apo group,Col-I,and Col-III protein levels were significantly lower than those in the KOA group(both P<.01),same as Col-I and Col-III mRNA levels(P=.0031;P=.0046).Compared with the KOA group,the protein levels of TGF-β1 and Smad 3 were significantly reduced(both P<.01),as were the mRNA levels of TGF-β1 and Smad 3(P=.0007;P=.0011).Conversely,the levels of protein and mRNA of Smad 7 were significantly higher than that in the KOA group(P<.01;P=.0271).Conclusion: Acupotomy could alleviate skeletal muscle fibrosis and delay KOA progress by inhibiting collagen deposition through the TGF-β/Smad pathway in the skeletal muscle of KOA rabbits.
基金Founded by the National Key Research and Development Program(No.2021YFB3802400)the National Natural Science Foundation of China(No.52161037)the Basic Research Project of Yunnan Province(No.202001AU070112)。
文摘The effect of deposition temperature on the morphology and optoelectronic performance of Ge/Si QDs grown by magnetron sputtering under low Ge deposition(~4 nm)was investigated by atomic force microscopy,Raman spectroscopy,and photoluminescence(PL)tests.The experimental results indicate that temperatures higher than 750℃effectively increase the crystallization rate and surface smoothness of the Si buffer layer,and temperatures higher than 600℃significantly enhance the migration ability of Ge atoms,thus increasing the probability of Ge atoms meeting and nucleating to form QDs on Si buffer layer,but an excessively high temperature will cause the QDs to undergo an Ostwald ripening process and thus develop into super large islands.In addition,some PL peaks were observed in samples containing small-sized,high-density Ge QDs,the photoelectric properties reflected by these peaks were in good agreement with the corresponding structural characteristics of the grown QDs.Our results demonstrate the viability of preparing high-quality QDs by magnetron sputtering at high deposition rate,and the temperature effect is expected to work in conjunction with other controllable factors to further regulate QD growth,which paves an effective way for the industrial production of QDs that can be used in future devices.
基金supported by Key Project of Natural Science Research of Anhui Universities(No.KJ2020A0341).
文摘Objective:Diabetic nephropathy(DN)is a deleterious microangiopathy of diabetes,constituting a critical determinant of fatality in diabetic patients.This work is purposed to disclose the effects and modulatory mechanism of BTG anti-proliferation factor 2(BTG2)during the pathological process of DN.Methods:BTG2 expression in kidney tissues of diabetic mice and high glucose(HG)-exposed human proximal tubular cell line HK-2 was assessed with Western blot and RT-qPCR.The diabetic mice model was constructed by streptozotocin injection and confirmed by the blood glucose level beyond 16.7 mmol/L.Hematoxylin and eosin(H&E)staining and measurement of kidney function hallmarks were conducted to assess kidney injury.Cell counting kit(CCK)-8 method and TUNEL assay appraised cell activity and apoptosis.Oil red O staining assayed lipid accumulation.Relevant commercial kits were used to estimate oxidative stress-related factors.Co-immunoprecipitation(Co-IP)assay testified the binding relationship of BTG2 with protein arginine methyltransferase 1(PRMT1).Results:BTG2 expression was significantly raised in renal tissues of diabetic mice and HK-2 cells exposed to HG.BTG2 deficiency improved viability and extenuated the apoptosis,lipid deposition as well as oxidative stress in HK-2 cells following HG exposure.In addition,PRMT1 was also overexpressed in HK-2 cells exposed to HG.BTG2 interacted with PRMT1 and positively modulated PRMT1 expression.The effects of BTG2 interference on viability,apoptosis,lipid deposition,and oxidative stress in HG-challenged HK-2 cells were partially abrogated by PRMT1 overexpression.Conclusion:Altogether,BTG2 might aggravate HK-2 cell injury in response to HG by binding with PRMT1,providing a novel target for the therapeutic strategy of DN.
基金the National Natural Science Foundation of China(Grant Nos.32192434,42007102)Natural Science Foundation of Fujian Province(Grant No.2020J01376)+1 种基金the Start-up Foundation for Advanced Talents in Sanming University(Grant No.19YG13)Educational Research Project for Young and Middle-aged Teachers of Fujian Provincial Department of Education(Grant No.JAT190704).
文摘Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function and whole-plant level C cycling.CO_(2)elevation and nitrogen(N)deposition,which are two major environmental issues worldwide,aff ect plant photosynthetic C assimilation and C release in forest ecosystems.However,information regarding the eff ect of CO_(2)elevation and N deposition on NSC storage in diff erent organs remains limited,especially regarding the trade-off between growth and NSC reserves.Therefore,here we analyzed the variations in the NSC storage in diff erent organs of Chinese fi r(Cunninghamia lanceolata)under CO_(2)elevation and N addition and found that NSC concentrations and contents in all organs of Chinese fi r saplings increased remarkably under CO_(2)elevation.However,N addition induced diff erential accumulation of NSC among various organs.Specifi cally,N addition decreased the NSC concentrations of needles,branches,stems,and fi ne roots,but increased the NSC contents of branches and coarse roots.The increase in the NSC contents of roots was more pronounced than that in the NSC content of aboveground organs under CO_(2)elevation.The role of N addition in the increase in the structural biomass of aboveground organs was greater than that in the increase in the structural biomass of roots.This result indicated that a diff erent tradeoff between growth and NSC storage occurred to alleviate resource limitations under CO_(2)elevation and N addition and highlights the importance of separating biomass into structural biomass and NSC reserves when investigating the eff ects of environmental change on biomass allocation.
基金the support from National Natural Science Foundation of China (22208355, 22178363 and 21978300)the financial support and mica samples from Changzi Wu and RIKA technology CO., LTD.
文摘The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pressure chemical vapor deposition(APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO_(2) grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl_(4) concentration increased from 0.38%to 2.44%. The grain size increased with the TiCl_(4) concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO_(2) clusters at the initial stage finally result to the agglomeration of fine TiO_(2) grains at high TiCl_(4) concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl_(4) concentration is below 0.90%.
文摘Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport industries.However,their widespread application is hindered by their low formability at room temperature due to limited slip systems.Cast Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high scrap.While casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain applications.Although metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast counterparts.Thus,MAM is a promising technique to produce Mg alloy parts.Directed energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive processes.However,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this technology.This review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and prospects.Furthermore,the predominant imperfections,notably inhomogeneous microstructure evolution and porosity,observed in Mg-alloy components manufactured through DED are discussed.Additionally,the preventive measures implemented to counteract the formation of these defects are explored.
基金the National Key R&D Program of China(No.2021YFB3701705).
文摘This work constructed a machine learning(ML)model to predict the atmospheric corrosion rate of low-alloy steels(LAS).The material properties of LAS,environmental factors,and exposure time were used as the input,while the corrosion rate as the output.6 dif-ferent ML algorithms were used to construct the proposed model.Through optimization and filtering,the eXtreme gradient boosting(XG-Boost)model exhibited good corrosion rate prediction accuracy.The features of material properties were then transformed into atomic and physical features using the proposed property transformation approach,and the dominant descriptors that affected the corrosion rate were filtered using the recursive feature elimination(RFE)as well as XGBoost methods.The established ML models exhibited better predic-tion performance and generalization ability via property transformation descriptors.In addition,the SHapley additive exPlanations(SHAP)method was applied to analyze the relationship between the descriptors and corrosion rate.The results showed that the property transformation model could effectively help with analyzing the corrosion behavior,thereby significantly improving the generalization ability of corrosion rate prediction models.
基金supported by the Key Research Program of the Chinese Academy of Sciences(grant number ZDRW-ZS-2021-1-2).
文摘Pulse rate is one of the important characteristics of traditional Chinese medicine pulse diagnosis,and it is of great significance for determining the nature of cold and heat in diseases.The prediction of pulse rate based on facial video is an exciting research field for getting palpation information by observation diagnosis.However,most studies focus on optimizing the algorithm based on a small sample of participants without systematically investigating multiple influencing factors.A total of 209 participants and 2,435 facial videos,based on our self-constructed Multi-Scene Sign Dataset and the public datasets,were used to perform a multi-level and multi-factor comprehensive comparison.The effects of different datasets,blood volume pulse signal extraction algorithms,region of interests,time windows,color spaces,pulse rate calculation methods,and video recording scenes were analyzed.Furthermore,we proposed a blood volume pulse signal quality optimization strategy based on the inverse Fourier transform and an improvement strategy for pulse rate estimation based on signal-to-noise ratio threshold sliding.We found that the effects of video estimation of pulse rate in the Multi-Scene Sign Dataset and Pulse Rate Detection Dataset were better than in other datasets.Compared with Fast independent component analysis and Single Channel algorithms,chrominance-based method and plane-orthogonal-to-skin algorithms have a more vital anti-interference ability and higher robustness.The performances of the five-organs fusion area and the full-face area were better than that of single sub-regions,and the fewer motion artifacts and better lighting can improve the precision of pulse rate estimation.
基金supports from National Natural Science Foundation of China (Grant No.62205117,52275429)National Key Research and Development Program of China (Grant No.2021YFF0502700)+3 种基金Young Elite Scientists Sponsorship Program by CAST (Grant No.2022QNRC001)West Light Foundation of the Chinese Academy of Sciences (Grant No.xbzg-zdsys-202206)Knowledge Innovation Program of Wuhan-Shuguang,Innovation project of Optics Valley Laboratory (Grant No.OVL2021ZD002)Hubei Provincial Natural Science Foundation of China (Grant No.2022CFB792).
文摘Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate limitations.In this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates.To our knowledge,this is the first reported practical dynamic interactive metasurface holographic system.We spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed sub-pattern.The switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame rate.Our approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational platform.According to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram creation.Our technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems.
基金supported by the National Natural Science Foundation of China(51975112,52375412)Fundamental Research Funds for Central Universities(N2203011)。
文摘Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures;however,the material compatibility and bondability directly affect the parts’formability and final quality.It is essential to understand the underlying printability of different material combinations based on an adapted process.Here,the printability disparities of two common and attractive material combinations(nickel-and iron-based alloys)are evaluated at the macro and micro levels via laser directed energy deposition(DED).The deposition processes were captured using in situ high-speed imaging,and the dissimilarities in melt pool features and track morphology were quantitatively investigated within specific process windows.Moreover,the microstructure diversity of the tracks and blocks processed with varied material pairs was comparatively elaborated and,complemented with the informative multi-physics modeling,the presented non-uniformity in mechanical properties(microhardness)among the heterogeneous material pairs was rationalized.The differences in melt flow induced by the unlike thermophysical properties of the material pairs and the resulting element intermixing and localized re-alloying during solidification dominate the presented dissimilarity in printability among the material combinations.This work provides an in-depth understanding of the phenomenological differences in the deposition of dissimilar materials and aims to guide more reliable DED forming of bimetallic parts.
基金supported by the Biological Breeding-National Science and Technology Major Project (2023ZD04072)the Innovation Program of Chinese Academy of Agricultural Sciencesthe Hainan Yazhou Bay Seed Lab (B23YQ1507)。
文摘In grain crops such as maize(Zea mays),leaf angle(LA)is a key agronomic trait affecting light interception and thus planting density and yield.Nitrogen(N)affects LA in plants,but we lack a good understanding of how N regulates LA.Here,we report that N deficiency enhanced lignin deposition in the ligular region of maize seedlings.In situ hybridization showed that the bZIP transcription factor gene ZmbZIP27 is mainly expressed in the phloem of maize vascular bundles.Under N-sufficient conditions,transgenic maize overexpressing ZmbZIP27 showed significantly smaller LA compared with wild type(WT).By contrast,zmbzip27_(ems)mutant showed larger LA under both N-deficient and N-sufficient conditions compared with WT.Overexpression of ZmbZIP27 enhanced lignin deposition in the ligular region of maize in the field.We further demonstrated that ZmbZIP27 could directly bind the promoters of the microRNA genes ZmMIR528a and ZmMIR528b and negatively regulate the expression levels of ZmmiR528.ZmmiR528 knockdown transgenic maize displayed erect architecture in the field by increasing lignin content in the ligular region of maize.Taken together,these results indicate that ZmbZIP27 regulates N-mediated LA size by regulating the expression of ZmmiR528 and modulating lignin deposition in maize.
基金supported by the National Natural Science Foundation of China(Grant Nos.42175099,42027804,42075073)the Innovative Project of Postgraduates in Jiangsu Province in 2023(Grant No.KYCX23_1319)+3 种基金supported by the National Natural Science Foundation of China(Grant No.42205080)the Natural Science Foundation of Sichuan(Grant No.2023YFS0442)the Research Fund of Civil Aviation Flight University of China(Grant No.J2022-037)supported by the National Key Scientific and Technological Infrastructure project“Earth System Science Numerical Simulator Facility”(Earth Lab)。
文摘The process of entrainment-mixing between cumulus clouds and the ambient air is important for the development of cumulus clouds.Accurately obtaining the entrainment rate(λ)is particularly important for its parameterization within the overall cumulus parameterization scheme.In this study,an improved bulk-plume method is proposed by solving the equations of two conserved variables simultaneously to calculateλof cumulus clouds in a large-eddy simulation.The results demonstrate that the improved bulk-plume method is more reliable than the traditional bulk-plume method,becauseλ,as calculated from the improved method,falls within the range ofλvalues obtained from the traditional method using different conserved variables.The probability density functions ofλfor all data,different times,and different heights can be well-fitted by a log-normal distribution,which supports the assumed stochastic entrainment process in previous studies.Further analysis demonstrate that the relationship betweenλand the vertical velocity is better than other thermodynamic/dynamical properties;thus,the vertical velocity is recommended as the primary influencing factor for the parameterization ofλin the future.The results of this study enhance the theoretical understanding ofλand its influencing factors and shed new light on the development ofλparameterization.
基金The financial support from the National Natural Science Foundation of China(Grant Nos.41941018 and 52074299)the Fundamental Research Funds for the Central Universities of China(Grant No.2023JCCXSB02)。
文摘Rockburst are often encountered in tunnel construction due to the complex geological conditions.To study the influence of unloading rate on rockburst,gneiss rockburst experiments were conducted under three groups of unloading rates.A high-speed photography system and acoustic emission(AE)system were used to monitor the entire process of rockburst process in real-time.The results show that the intensity of gneiss rockburst decreases with decrease of unloading rate,which is manifested as the reduction of AE energy and fragments ejection velocity.The mechanisms are proposed to explain this effect:(i)The reduction of unloading rate changes the crack propagation mechanism in the process of rockburst.This makes the rockbursts change from the tensile failure mechanism at high unloading rate to the tension-shear mixed failure mechanism at low unloading rate,and more energy released in the form of shear crack propagation.Then,less strain energy is converted into kinetic energy of fragments ejection.(ii)Less plate cracking degree of gneiss has taken shape due to decrease of unloading rate,resulting in the destruction of rockburst incubation process.The enlightenments of reducing the unloading rate for the project are also described quantitatively.The rockburst magnitude is reduced from the medium magnitude at the unloading rate of 0.1 MPa/s to the slight magnitude at the unloading rate of 0.025 MPa/s,which was judged by the ejection velocity.
文摘The mutation rate is a pivotal biological characteristic,intricately governed by natural selection and historically garnering considerable attention.Recent advances in high-throughput sequencing and analytical methodologies have profoundly transformed our understanding in this domain,ushering in an unprecedented era of mutation rate research.This paper aims to provide a comprehensive overview of the key concepts and methodologies frequently employed in the study of mutation rates.It examines various types of mutations,explores the evolutionary dynamics and associated theories,and synthesizes both classical and contemporary hypotheses.Furthermore,this review comprehensively explores recent advances in understanding germline and somatic mutations in animals and offers an overview of experimental methodologies,mutational patterns,molecular mechanisms,and driving forces influencing variations in mutation rates across species and tissues.Finally,it proposes several potential research directions and pressing questions for future investigations.
基金supported by grants from the Ministry of Science and Technology(Grant Nos.2021FY100101,2019QZKK0901)the National Natural Science Foundation of China(Grant Nos.41941016,42230312,42020104007)China Geological Survey(Grant No.DD20221630).
文摘The Earth’s surface kinematics and deformation are fundamental to understanding crustal evolution.An effective research approach is to estimate regional motion field and deformation fields based on modern geodetic networks.If the discrete observed velocity field is obtained,the velocity related fields,such as dilatation rate and maximum shear strain rate,can be estimated by applying varied mathematical approaches.This study applied Akaike's Bayesian Information Criterion(ABIC)method to calculate strain rate fields constrained by GPS observations in the southeast Tibetan Plateau.Comparison with results derived from other three methods revealed that our ABIC-derived strain rate fields were more precise.The maximum shear strain rate highlighted the Xianshuihe–Xiaojiang fault system as the main boundary for the outward migration of material in southeastern Tibet,indicating rotation of eastern Tibet material around the eastern Himalaya rather than whole extrusion along a fixed channel.Additionally,distinct dilatation rate patterns in the northeast and southwest regions of the fault system were observed.The northeast region,represented by the Longmenshan area,exhibited negative dilatational anomalies;while the southwest region,represented by the Jinsha River area north of 29°N,displayed positive dilatational anomalies.This indicates compression in the former and extension in the latter.Combined with deep geophysical observations,we believe that the upper and lower crusts of the Jinsha River area north of 29°N are in an entire expanding state,probably caused by the escape-drag effect of material.The presence of a large,low-viscosity region south of 29°N may not enable the entire escape of the crust,but instead result in a differential escape of the lower crust faster than the upper crust.
基金supported by the Double Support Project (035–2221993229)。
文摘Background Adequate level of carbohydrates in aquafeeds help to conserve protein and reduce cost. However, studies have indicated that high-carbohydrate(HC) diet disrupt the homeostasis of the gut–liver axis in largemouth bass, resulting in decreased intestinal acetate and butyrate level.Method Herein, we had concepted a set of feeding experiment to assess the effects of dietary sodium acetate(SA) and sodium butyrate(SB) on liver health and the intestinal microbiota in largemouth bass fed an HC diet. The experimental design comprised 5 isonitrogenous and isolipidic diets, including LC(9% starch), HC(18% starch), HCSA(18% starch;2 g/kg SA), HCSB(18% starch;2 g/kg SB), and HCSASB(18% starch;1 g/kg SA + 1 g/kg SB). Juvenile largemouth bass with an initial body weight of 7.00 ± 0.20 g were fed on these diets for 56 d.Results We found that dietary SA and SB reduced hepatic triglyceride accumulation by activating autophagy(ATG101, LC3B and TFEB), promoting lipolysis(CPT1α, HSL and AMPKα), and inhibiting adipogenesis(FAS, ACCA, SCD1 and PPARγ). In addition, SA and SB decreased oxidative stress in the liver(CAT, GPX1α and SOD1) by activating the Keap1-Nrf2 pathway. Meanwhile, SA and SB alleviated HC-induced inflammation by downregulating the expression of pro-inflammatory factors(IL-1β, COX2 and Hepcidin1) through the NF-κB pathway. Importantly, SA and SB increased the abundance of bacteria that produced acetic acid and butyrate(Clostridium_sensu_stricto_1). Combined with the KEGG analysis, the results showed that SA and SB enriched carbohydrate metabolism and amino acid metabolism pathways, thereby improving the utilization of carbohydrates. Pearson correlation analysis indicated that growth performance was closely related to hepatic lipid deposition, autophagy, antioxidant capacity, inflammation, and intestinal microbial composition.Conclusions In conclusion, dietary SA and SB can reduce hepatic lipid deposition;and alleviate oxidative stress and inflammation in largemouth bass fed on HC diet. These beneficial effects may be due to the altered composition of the gut microbiota caused by SA and SB. The improvement effects of SB were stronger than those associated with SA.
基金supported by the National Natural Science Foundation of China(3196140162).
文摘Warming and nitrogen(N)deposition are two important drivers of global climate changes.Coarse woody debris(CWD)contains a large proportion of the carbon(C)in the total global C pool.The composition of soil microbial communities and environmental changes(i.e.,N deposition and warming)are the key drivers of CWD decomposition,but the interactive impact between N deposition and warming on the composition of soil microbial communities and CWD decomposition is still unclear.In a laboratory experiment,we study and simulate respiration during decomposition of the CWD(C 98)of Cryptomeria japonica(CR)and Platycarya strobilacea(PL)in response to warming and N deposition over 98 days.Resuts show that either warming or N addition signifi cantly accelerated the C 98 of the two tree species by altering the soil microbial community(bacterial:fungi and G+:G–).The combined treatment(warming+N)resulted in a decomposition eff ect equal to the sum of the individual eff ects.In addition,the species composition of bacteria and fungi was obviously aff ected by warming.However,N deposition had a remarkable infl uence on G+:G–.Our results indicated that N deposition and warming will observably alter the composition and growth of the microbial community and thus work synergistically to accelerate CWD decomposition in forest ecosystems.We also present evidence that N deposition and warming infl uenced the composition and balance of soil microbial communities and biogeochemical cycling of forest ecosystems.