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Snow and regolith albedo variations using CRISM data at McMurdo crater,Mars

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Earth and Planetary Physics 2024年第2期8卷 338-355页

作者： Sehajpal Singh Deepak Singh Centre of studies in Resources Engineering Indian Institute of Technology BombayMumbaiIndia

The cryosphere component provides the most reliable and insightful indications of any planet’s climate dynamics.Using data from the Compact Reconnaissance Imaging Spectrometer for Mars(CRISM),we develop a novel approach to determining the broadband Visible and Near Infrared(VNIR)albedo of the Martian surface.This study focuses on albedo changes in the McMurdo crater,part of Mars’s south polar layer deposits.We compare seasonal and interannual variations of the McMurdo surface albedo before,during,and after the Global Dust Storm(GDS)of Martian Year(MY)34.As the seasons progressed from spring to summer,the mean albedo in MY 32 and 34 plunged by over 40%,by about 35%in MY 33,and by slightly more than 30%in MY 35.Compared interannually,however,mean albedo values within both seasons(spring and summer)exhibited no significant differences in those same years.Notably,interannual albedo difference maps reveal albedo variation of more than±0.3 in certain regions of the crater.Considering only snow-covered pixels,interannual albedo differences suggest that Mars dust had a pervasive impact on Mars’s cryosphere.Variations in maximum and minimum albedo values as high as 0.5 were observed,depending upon differences in the dust levels in Martian snow/ice.The maximum and the minimum snow albedo values were lowest in MY 34,indicating the effect of the intense dust storm event that year.The average snow albedo decreased from 0.45 in MY 32 to 0.40 in MY 33 and to 0.33 in MY 34,and then rose back to 0.40 in MY 35.This trajectory suggests a temporary deposition of dust,partially reversed after the GDS by self-cleaning mechanisms(local aeolian process and CO_(2)sublimation/deposition cycle).

关键词： Mars Martian ice albedo dust storm Mars surface Martian climate

Seismic control of multi-degrees-of-freedom structures by vertical mass isolation method using MR dampers

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 503-510页

作者： Mohamad Shahrokh Abdi Masoud Nekooei Mohammad-Ali Jafari Department of Civil Engineering Marivan BranchIslamic Azad UniversityMarivan ***Iran Department of Civil Engineering Science and Research BranchIslamic Azad UniversityTehran ***Iran Structural Department of Transmission and Distribution Research Center Niroo Research Institute(NRI)Tehran ***Iran

Vertical mass isolation(VMI)is one of the novel methods for the seismic control of structures.In this method,the entire structure is assumed to consist of two mass and stiffness subsystems,and an isolated layer is located among them.In this study,the magnetorheological damper in three modes:passive-off,passive-on,and semi-active mode with variable voltage between zero and 9 volts was used as an isolated layer between two subsystems.Multi-degrees-of-freedom structures with 5,10,and 15 floors in two dimensions were examined under 11 pairs of near field earthquakes.On each level,the displacement of MR dampers was taken into account.The responses of maximum displacement,maximum inter-story drift,and maximum base shear in controlled and uncontrolled buildings were compared to assess the suggested approach for seismic control of the structures.According to the results,the semi-active control method can reduce the response by more than 12%compared to the uncontrolled mode in terms of maximum displacement of the mass subsystem of the structures.This method can reduce more than 16%and 20%of the responses compared to the uncontrolled mode in terms of maximum inter-story drift and base shear of the structure,respectively.

关键词： seismic control vertical mass isolation base shear magnetorheological damper semi-active control

BCCLR:A Skeleton-Based Action Recognition with Graph Convolutional Network Combining Behavior Dependence and Context Clues

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Computers, Materials & Continua 2024年第3期78卷 4489-4507页

作者： Yunhe Wang Yuxin Xia Shuai Liu College of Information Science and Engineering Institute of Interdisciplinary StudiesHunan Normal UniversityChangsha410081China School of Educational Sciences Institute of Interdisciplinary StudiesHunan Normal UniversityChangsha410081China

In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal graph.Most GCNs define the graph topology by physical relations of the human joints.However,this predefined graph ignores the spatial relationship between non-adjacent joint pairs in special actions and the behavior dependence between joint pairs,resulting in a low recognition rate for specific actions with implicit correlation between joint pairs.In addition,existing methods ignore the trend correlation between adjacent frames within an action and context clues,leading to erroneous action recognition with similar poses.Therefore,this study proposes a learnable GCN based on behavior dependence,which considers implicit joint correlation by constructing a dynamic learnable graph with extraction of specific behavior dependence of joint pairs.By using the weight relationship between the joint pairs,an adaptive model is constructed.It also designs a self-attention module to obtain their inter-frame topological relationship for exploring the context of actions.Combining the shared topology and the multi-head self-attention map,the module obtains the context-based clue topology to update the dynamic graph convolution,achieving accurate recognition of different actions with similar poses.Detailed experiments on public datasets demonstrate that the proposed method achieves better results and realizes higher quality representation of actions under various evaluation protocols compared to state-of-the-art methods.

关键词： Action recognition deep learning GCN behavior dependence context clue self-attention

Experimental investigation into effects of the natural polymer and nanoclay particles on the EOR performance of chemical flooding in carbonate reservoirs

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Petroleum Science 2024年第2期21卷 951-961页

作者： Amir Mohammad Zamani Ashkan Moslemi Kamran Hassani Department of Petroleum Engineering Islamic Azad University Science and Research BranchTehranIran institute of Petroleum Engineering University of TehranTehranIran

This paper aims to investigate the tragacanth gum potential as a natural polymer combined with natural clay mineral(montmorillonite,kaolinite,and illite)nanoparticles(NPs)to form NP-polymer suspension for enhanced oil recovery(EOR)in carbonate reservoirs.Thermal gravimetric analysis(TGA)tests were conducted initially in order to evaluate the properties of tragacanth gum.Subsequently,scanning electron microscopy(SEM)and energy-dispersive X-ray(EDX)tests were used to detect the structure of clay particles.In various scenarios,the effects of natural NPs and polymer on the wettability alteration,interfacial tension(IFT)reduction,viscosity improvement,and oil recovery were investigated through contact angle system,ring method,Anton Paar viscometer,and core flooding tests,respectively.The entire experiment was conducted at 25,50,and 75℃,respectively.According to the experimental results,the clay minerals alone did not have a significant effect on viscosity,but the addition of minerals to the polymer solution leads to the viscosity enhancement remarkably,resulting mobility ratio improvement.Among clay NPs,the combination of natural polymer and kaolinite results in increased viscosity at all temperatures.Considerable wettability alteration was also observed in the case of natural polymer and illite NPs.Illite in combination with natural polymer showed an ability in reducing IFT.Finally,the results of displacement experiments revealed that the combination of natural polymer and kaolinite could be the best option for EOR due to its substantial ability to improve the recovery factor.

关键词： Chemical flooding Tragacanth gum Clay nanoparticle Wettability IFT

Evaluating innovation ecosystem resiliency using agent-based modeling and systems dynamics

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Journal of Safety Science and Resilience 2024年第2期5卷 204-221页

作者： Soheila Abdi Mehdi Yazdani Esmaeil Najafi Department of Industrial Engineering Science and Research BranchIslamic Azad UniversityTehranIran Department of Industrial Engineering Qazvin BranchIslamic Azad UniversityQazvinIran

Evaluating the resilience of the innovation ecosystem to maintain its performance,in the sense of resistance to disruption and recovery after it,has recently received more attention.Several studies have been conducted to model different ecosystems and evaluate their resilience.However,modeling the innovation ecosystem from a holistic perspective and performing a quantitative assessment of its resilience have received less attention.This paper models the innovation ecosystem holistically and evaluates its resilience index using a quantitative approach through five main steps.In the first step,a case study related to the innovation ecosystem of Iran's Ministry of Energy,called the Power Innovation Ecosystem,is modeled by combining system dynamics and agent-based modeling.Upon validating the model in the second step,the disruption of the loss of experts is investigated in the third step,and all possible actions to recover each actor are analyzed.In the fourth step,the performance of the ecosystem is simulated before and after the disruption using the data gathered in the previous steps.Finally,resilience is calculated in two different ways in the fifth step.Several improvement solutions are also suggested when considering that the resilience index of the innovation ecosystem is at a medium level.This research may assist policymakers in observing the resilience level of the innovation ecosystem based on the proposed model.By applying strategic changes to this model,they can determine the effects of their policies and make the most appropriate decisions to increase the resilience of the innovation ecosystem.

关键词： Resilience index innovation ecosystem System dynamics Agent-based modeling

The US Election in 2024 and the Trend of the Ukraine Crisis

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和平与发展 2024年第2期 192-194页

作者： Zhang Wenzong Shi Guannan institute of American studies CICIR

The crisis in Ukraine,which has dragged on for more than two years,and whether military aid to Ukraine should continue are major issues debated and fought over by the two parties in the United States prior to the 2024 election.Regarding whether to continue to aid Ukraine,various political forces in the United States have chosen sides in the election campaign,which can be roughly divided into the“aid camp”and the“stop-aid camp”according to their positions.

关键词： continue positions election

Impact of lifestyle interventions on pathogenesis of nonalcoholic fatty liver disease

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World Journal of Gastroenterology 2024年第20期30卷 2633-2637页

作者： Wafaa Mohamed Ezzat Department of Internal Medicine Medical Research and Clinical Studies InstituteNational Research CenterGiza 12311Egypt

This editorial builds on the article titled“Establishment and validation of an adherence prediction system for lifestyle interventions in non-alcoholic fatty liver disease”by Zeng et al.We carried out a critical examination of nonalcoholic fatty liver disease(NAFLD)pathogenesis and how lifestyle interventions could facilitate disease resolution,particularly highlighting that non-alcoholic steatohepatitis(NASH)is a severe form of NAFLD.Our discussion details that weight loss is a pivotal factor in disease outcomes:A 3%-5%reduction is enough for resolution in 50%of non-obese individuals,while a 7%-10%reduction achieves similar benefits in obese individuals,as demonstrated by magnetic resonance spectroscopy.Additionally,the editorial underscores that such lifestyle changes are instrumental not only in resolving NAFLD but also in reversing hepatic steatosis and inflammation.These insights,derived from the research,emphasize the critical role of personalized lifestyle modifications in halting the progression of NAFLD to NASH and even reversing fibrosis,thus offering a template for effective patient management.

关键词： Nonalcoholic fatty liver disease Non-alcoholic steatohepatitis Diet Physical activity Life style

The Effect of Spironolactone Loading on the Properties of 3D-Printed Polycaprolactone/Gold Nanoparticles Composite Scaffolds for Myocardial Tissue Engineering

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Journal of Bionic Engineering 2024年第2期21卷 924-937页

作者： Sharareh Ghaziof Shahrokh Shojaei Mehdi Mehdikhani Mohammad Khodaei Milad Jafari Nodoushan Department of Biomedical Engineering Central Tehran BranchIslamic Azad UniversityTehran***Iran Stem Cells Research Center Tissue Engineering and Regenerative Medicine InstituteCentral Tehran BranchIslamic Azad UniversityTehran***Iran Department of Biomedical Engineering Faculty of EngineeringUniversity of IsfahanIsfahan***Iran Materials Engineering Group Golpayegan College of EngineeringIsfahan University of TechnologyGolpayegan87717-67498Iran Hard Tissue Engineering Research Center Tissue Engineering and Regenerative Medicine InstituteCentral Tehran BranchIslamic Azad UniversityTehran***Iran

Engineered cardiac constructs(ECC)aid in the progression of regenerative medicine,disease modeling and targeted drug delivery to adjust and aim the release of remedial combination as well as decrease the side effects of drugs.In this research,polycaprolactone/gold nanoparticles(PCL/GNPs)three-dimensional(3D)composite scaffolds were manufactured by 3D printing using the fused deposition modeling(FDM)method and then coated with gelatin/spironolactone(GEL/SPL).Scanning electron microscopy(SEM)and Fourier transform-infrared spectroscopy(FTIR–ATR)were applied to characterize the samples.Furthermore,drug release,biodegradation,behavior of the myoblasts(H9C2)cell line,and cytotoxicity of the 3D scaffolds were evaluated.The microstructural observation of the scaffolds reported interconnected pores with 150–300µm in diameter.The 3D scaffolds were degraded significantly after 28 days of immersion in stimulated body fluid(SBF),with the maximum rate of GEL-coated 3D scaffolds.SPL release from cross-linked GEL coating demonstrated the excess of drug release over time,and according to the control release systems,the drug delivery systems(DDS)went into balance after the 14th day.In addition,cell culture study showed that with the addition of GNPs,the proliferation of(H9C2)was enhanced,and with GEL/SPL coating the cell attachment and viability were improved significantly.These findings suggested that PCL/GNPs 3D scaffolds coated with GEL/SPL can be an appropriate choice for myocardial tissue engineering.

关键词： Polycaprolactone Gold nanoparticles Drug delivery systems Spironolactone Cell behavior Myoblasts

Visible-light-activated aziridination reaction enables simultaneous resolving of C=C bond location and the sn-position isomers in lipids

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Chinese Chemical Letters 2024年第4期35卷 481-485页

作者： Qiongqiong Wan Yanan Xiao Guifang Feng Xin Dong Wenjing Nie Ming Gao Qingtao Meng Suming Chen The institute for Advanced studies Renmin Hospital of Wuhan UniversityWuhan UniversityWuhan 430072China

There is a close relationship between the biological functions of lipids and their structures, and various isomers greatly increases the complexity of lipid structures. The C=C bond location and sn-position are two of the essential attributes that determine the structures of unsaturated lipids. However, simultaneous identification of both attributes remains challenging. Here, we develop a visible-light-activated aziridination reaction system, which enables the dual-resolving of the C=C bond location and sn-position isomerism of in lipids when combines with liquid chromatography-mass spectrometry(LC-MS). Based on the derivatization of C=C bonds with Ph I=NTs, their location in lipids could be easily identified by tandem MS. Especially, the sn-position isomers of unsaturated phosphatidylcholine(PC) can be separated and quantified by LC-MS after the derivatization. By using the proposed method, the significant changes of the sn-position isomers ratios of PC in mouse brain ischemia were revealed. This study offers a powerful tool for deep lipid structural biology.

关键词： Aziridination Lipid isomers C=C bond location sn-Position Mass spectrometry