Objective： To study the efficacy and safety of autologous transplantation of bone marrow mesenchymal stem cells on diabetic patients with lower limb ischemia. Methods： Fifty Type 2 diabetic patients with lower limb ...Objective： To study the efficacy and safety of autologous transplantation of bone marrow mesenchymal stem cells on diabetic patients with lower limb ischemia. Methods： Fifty Type 2 diabetic patients with lower limb ischemia were enrolled and randomized to either transplanted group or control group. Patients in both group received the same conventional treatment. Meanwhile, 20 ml bone marrow from each transplanted patient were collected, and the mesenchymal stem cells were separated by density gradient centrifugation and cultured in the medium with autologous serum. After three-weeks adherent culture in vitro, 7.32×10^8-5.61×10^9 mesenchymal stem cells were harvested and transplanted by multiple intramuscular and hypodermic injections into the impaired lower limbs. Results： At the end of 12-week follow-up, 5 patients were excluded from this study because of clinical worsening or failure of cell culture. Main ischemic symptoms, including rest pain and intermittent claudication, were improved significantly in transplanted patients. The ulcer healing rate of the transplanted group （1 5 of 18, 83.33%） was significantly higher than that of the control group （9 of 20, 45.00%, P=0.012）.The mean of resting ankle-brachial index （ABI） in transplanted group significantly was increased from 0.61±0.09 to 0.74±0.11 （P〈0.001）. Magnetic resonance angiography （MRA） demonstrated that there were more patients whose score of new vessels exceeded or equaled to 2 in the transplant patients （11 of 15） than in control patients （2 of 14, P=0.001）. Lower limb amputation rate was significantly lower in transplanted group than in the control group （P=0.040）. No adverse effects was observed in transplanted group. Conclusion： These results indicate that the autologous transplantation of bone marrow mesenchymal stem cells relieves critical lower limb ischemia and promotes ulcers healing in Type 2 diabetic patients.展开更多
The physical and mechanical change processes of coal and rock are closely related to energy transformation,and the destruction and failure of coal and rock is an instability phenomena driven by energy change.However,t...The physical and mechanical change processes of coal and rock are closely related to energy transformation,and the destruction and failure of coal and rock is an instability phenomena driven by energy change.However,the energy change of large-scale coal rock in the mine site is hardly calculated accurately,making it difficult to monitor coal-rock systematic failure and collapse from the perspective of energy.By the energy dissipation EMR monitoring system,we studied the damage and failure of coal and rock with bursting liability from the energy dissipation point using the geophysical method-EMR,and explored the energy dissipation characteristics during uniaxial compression and their main influencing factors.The results show that under displacement-control loading mode,there are 2 types of energy dissipation trends for both coal and rock with bursting liability.The type Ⅰ trend is a steady increase one during the whole process,therein,the energy dissipation of rock samples is accelerated at the peak load.The type Ⅱ trend energy is a W-shaped fluctuating one containing 6 stages.Under load-control loading mode,there is one energy dissipation trend of shock downward-steady rise.Besides that,rock samples also present a trend of 4 stages.The energy dissipation characteristics of coal and rockduring loading failure process can be used as effective criteria to assess whether they are in a stable or destructive stage.The factors influencing energy dissipation in the loading failure process of coal and rock mainly include strength,homogeneity,and energy input efficiency.展开更多
Orbital-scale global climatic changes during the late Quaternary are dominated by high-latitude influenced~100,000-year global ice-age cycles and monsoon influenced~23,000-year low-latitude hydroclimate variations.How...Orbital-scale global climatic changes during the late Quaternary are dominated by high-latitude influenced~100,000-year global ice-age cycles and monsoon influenced~23,000-year low-latitude hydroclimate variations.However,the shortage of highly-resolved land temperature records remains a limiting factor for achieving a comprehensive understanding of long-term low-latitude terrestrial climatic changes.Here,we report paired mean annual air temperature(MAAT)and monsoon intensity proxy records over the past 88,000 years from Lake Tengchongqinghai in southwestern China.While summer monsoon intensity follows the~23,000-year precession beat found also in previous studies,we identify previously unrecognized warm periods at 88,000-71,000 and 45,000-22,000 years ago,with 2-3℃amplitudes that are close to our recorded full glacial-interglacial range.Using advanced transient climate simulations and comparing with forcing factors,we find that these warm periods in our MAAT record probably depends on local annual mean insolation,which is controlled by Earth’s~41,000-year obliquity cycles and is anti-phased to annual mean insolation at high latitudes.The coincidence of our identified warm periods and intervals of high-frequent dated archaeological evidence highlights the importance of temperature on anatomically modern humans in Asia during the last glacial stage.展开更多
Considerable efforts have been made to extend temperature records beyond the instrumental period through proxy reconstructions,in order to further understand the mechanisms of past climate variability.Yet,the global c...Considerable efforts have been made to extend temperature records beyond the instrumental period through proxy reconstructions,in order to further understand the mechanisms of past climate variability.Yet,the global coverage of existing temperature records is still limited,especially for some key regions like the Tibetan Plateau and for earlier times including the Medieval Warm Period(MWP).Here we present decadally-resolved,alkenone-based,temperature records from two lakes on the northern Tibetan Plateau.Characterized by marked temperature variability,our records provide evidence that temperatures during the MWP were slightly higher than the modern period in this region.Further,our temperature reconstructions,within age uncertainty,can be well correlated with solar irradiance changes,suggesting a possible link between solar forcing and natural climate variability,at least on the northern Tibetan Plateau.展开更多
To evaluate the validity of cloud top height (CTH) retrievals from FY-4A, the first of China's next-generation geostationary meteorological satellite series, the retrievals are compared to those from Himawari-8, C...To evaluate the validity of cloud top height (CTH) retrievals from FY-4A, the first of China's next-generation geostationary meteorological satellite series, the retrievals are compared to those from Himawari-8, CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and Moderate Resolution Imaging Spectroradiometer (MODIS) operational products from August to October 2017. Regarding CTHs from CloudSat, CALIPSO, and MODIS as truth, the results show that the performance of FY-4A CTH retrievals is similar to that of Himawari-8. Both FY-4A and Himawari-8 retrieve reasonable CTH values for single-layer clouds, but perform poorly for multi-layer clouds. The mean bias error (MBE) shows that the mean value of FY-4A CTH retrievals is smaller than that of Himawari-8 for single-layer clouds but larger for multi-layer clouds. For ice crystal clouds, both FY-4A and Himawari-8 obtain the underestimated CTHs. However, there is a tendency for FY-4A and Himawari-8 to overestimate the CTH values of CloudSat and CALIPSO mainly for low level liquid water clouds. The temperature inversion near the tops of water clouds may result in an overestimation of CTHs. According to the MBE change with altitude, FY-4A and Himawari-8 overestimate the CTHs mainly for clouds below 3 km, and the overestimation is slightly more apparent in Himawari-8 data than that in FY-4A values. As the cloud optical thickness (COT) increases, the CTH bias of FY-4A CTH retrievals gradually decreases. Two typical cases are analyzed to illustrate the differences between different satellites' CTH retrievals in detail.展开更多
Flowering time and stem growth habit determine inflorescence architecture in soybean, which in turn influences seed yield. Dt1, a homolog of Arabidopsis TERMINAL FLOWER 1(TFL1), is a major controller of stem growth ha...Flowering time and stem growth habit determine inflorescence architecture in soybean, which in turn influences seed yield. Dt1, a homolog of Arabidopsis TERMINAL FLOWER 1(TFL1), is a major controller of stem growth habit, but its underlying molecular mechanisms remain unclear.Here, we demonstrate that Dt1 affects node number and plant height, as well as flowering time,in soybean under long-day conditions. The b ZIP transcription factor FDc1 physically interacts with Dt1, and the FDc1-Dt1 complex directly represses the expression of APETALA1(AP1). We propose that FT5 a inhibits Dt1 activity via a competitive interaction with FDc1 and directly upregulates AP1. Moreover, AP1 represses Dt1 expression by directly binding to the Dt1 promoter, suggesting that AP1 and Dt1 form a suppressive regulatory feedback loop to determine the fate of the shoot apical meristem. These findings provide novel insights into the roles of Dt1 and FT5 a in controlling the stem growth habit and flowering time in soybean, which determine the adaptability and grain yield of this important crop.展开更多
Wastewater treatment plants(WWTPs) are deemed reservoirs of antibiotic resistance genes(ARGs). Bacterial phylogeny can shape the resistome in activated sludge. However, the co-occurrence and interaction of ARGs abunda...Wastewater treatment plants(WWTPs) are deemed reservoirs of antibiotic resistance genes(ARGs). Bacterial phylogeny can shape the resistome in activated sludge. However, the co-occurrence and interaction of ARGs abundance and bacterial communities in different WWTPs located at continental scales are still not comprehensively understood. Here, we applied quantitative PCR and Miseq sequence approaches to unveil the changing profiles of ARGs(sul1, sul2, tet W, tet Q, tet X), int I1 gene, and bacterial communities in 18 geographically distributed WWTPs. The results showed that the average relative abundance of sul1 and sul2 genes were 2.08 × 10^(-1) and 1.32 × 10^(-1) copies/16 S rRNA copies, respectively. The abundance of tet W gene was positively correlated with the Shannon diversity index(H′), while both studied sul genes had significant positive relationship with the int I1 gene. The highest average relative abundances of sul1, sul2, tet X, and int I1 genes were found in south region and oxidation ditch system. Network analysis found that 16 bacterial genera co-occurred with tet W gene. Co-occurrence patterns were revealed distinct community interactions between aerobic/anoxic/aerobic and oxidation ditch systems. The redundancy analysis model plot of the bacterial community composition clearly demonstrated that the sludge samples were significant differences among those from the different geographical areas,and the shifts in bacterial community composition were correlated with ARGs. Together,these findings from the present study will highlight the potential risks of ARGs and bacterial populations carrying these ARGs, and enable the development of suitable technique to control the dissemination of ARGs from WWTPs into aquatic environments.展开更多
Land surface water(LSW) is one of the most important resources for human survival and development, and it is also a main component of global water recycling. A full understanding of the spatial distribution of land su...Land surface water(LSW) is one of the most important resources for human survival and development, and it is also a main component of global water recycling. A full understanding of the spatial distribution of land surface water and a continuous measuring of its dynamics can support to diagnose the global ecosystem and environment. Based on the Global Land 30-water 2000 and Global Land 30-water 2010 products, this research analyzed the spatial distribution pattern and temporal fluctuation of land surface water under scale-levels of global, latitude and longitude, continents, and climate zones. The Global Land 30-water products were corrected the temporal inconsistency of original remotely sensed data using MODIS time-series data, and then calculated the indices such as water area, water ration and coefficient of spatial variation for further analysis. Results show that total water area of land surface is about 3.68 million km2(2010), and occupies 2.73% of land area. The spatial distribution of land surface water is extremely uneven and is gathered mainly in mid- to high-latitude area of the Northern Hemisphere and tropic area. The comparison of water ratio between 2000 and 2010 indicates the overall fluctuation is small but spatially differentiated. The Global Land 30-water products and the statistics provided the fundamental information for analyzing the spatial distribution pattern and temporal fluctuation of land surface water and diagnosing the global ecosystem and environment.展开更多
In order to ameliorate the electrochemical hydrogen storage performances of La-Mg–Ni system A_2B_7-type electrode alloys, the partial substitution of M (M = Zr, Pr) for La was performed. The melt spinning technology ...In order to ameliorate the electrochemical hydrogen storage performances of La-Mg–Ni system A_2B_7-type electrode alloys, the partial substitution of M (M = Zr, Pr) for La was performed. The melt spinning technology was used to fabricate the La_(0.75-x)M_xMg_0.25Ni_3.2Co_0.2Al_0.1 (M = Zr, Pr; x = 0, 0.1) electrode alloys. The influences of the melt spinning and substituting La with M (M = Zr, Pr) on the structures and the electrochemical hydrogen storage characteristics of the alloys were investigated. The analysis of XRD, SEM, and TEM reveals that the as-cast and spun alloys have a multiphase structure composed of two main phases (La, Mg)_2Ni_7 and LaNi_5 as well as a residual phase LaNi_2 . The as-spun (M = Pr) alloy displays an entire nanocrystalline structure, while an amorphous-like structure is detected in the as-spun (M = Zr) alloy, implying that the substitution of Zr for La facilitates the amorphous formation. The electrochemical measurements exhibit that the substitution of Pr for La clearly increases the discharge capacity of the alloys; however, the Zr substitution brings on an adverse impact. Meanwhile, the M (M = Zr, Pr) substitution significantly enhances its cycle stability. The melt spinning exerts an evident effect on the electrochemical performances of the alloys, whose discharge capacity and high rate discharge ability (HRD) first mount up and then fall with the growing spinning rate, whereas their cycle stabilities monotonously augment as the spinning rate increases.展开更多
Background:Schwann cell-like cells(SCLCs),differentiated from mesenchymal stem cells,have shown promising outcomes in the treatment of peripheral nerve injuries in preclinical studies.However,certain clinical obstacle...Background:Schwann cell-like cells(SCLCs),differentiated from mesenchymal stem cells,have shown promising outcomes in the treatment of peripheral nerve injuries in preclinical studies.However,certain clinical obstacles limit their application.Hence,the primary aim of this study was to investigate the role of exosomes derived from SCLCs(SCLCs-exo)in peripheral nerve regeneration.Methods:SCLCs were differentiated from human amniotic mesenchymal stem cells(hAMSCs)in vitro and validated by immunofluorescence,real-time quantitative PCR and western blot analysis.Exosomes derived from hAMSCs(hAMSCs-exo)and SCLCs were isolated by ultracentrifugation and validated by nanoparticle tracking analysis,WB analysis and electron microscopy.A prefab-ricated nerve graft was used to deliver hAMSCs-exo or SCLCs-exo in an injured sciatic nerve rat model.The effects of hAMSCs-exo or SCLCs-exo on rat peripheral nerve injury(PNI)regeneration were determined based on the recovery of neurological function and histomorphometric variation.The effects of hAMSCs-exo or SCLCs-exo on Schwann cells were also determined via cell prolifer-ation and migration assessment.Results:SCLCs significantly expressed the Schwann cell markers glial fibrillary acidic protein and S100.Compared to hAMSCs-exo,SCLCs-exo significantly enhanced motor function recov-ery,attenuated gastrocnemius muscle atrophy and facilitated axonal regrowth,myelin forma-tion and angiogenesis in the rat model.Furthermore,hAMSCs-exo and SCLCs-exo were effi-ciently absorbed by Schwann cells.However,compared to hAMSCs-exo,SCLCs-exo signifi-cantly promoted the proliferation and migration of Schwann cells.SCLCs-exo also significantly upregulated the expression of a glial cell-derived neurotrophic factor,myelin positive regulators(SRY-box transcription factor 10,early growth response protein 2 and organic cation/carnitine transporter 6)and myelin proteins(myelin basic protein and myelin protein zero)in Schwann cells.Conclusions:These findings suggest that SCLCs-exo can more efficiently prom展开更多
Constructing graphene-based heterostructures with large interfacial area is an efficient approach to enhance the electrochemical performance of supercapacitors but remains great challenges in their synthesis.Herein,a ...Constructing graphene-based heterostructures with large interfacial area is an efficient approach to enhance the electrochemical performance of supercapacitors but remains great challenges in their synthesis.Herein,a novel ultra-small amorphous Fe_(2)O_(3)nanodots/graphene heterostructure(a-Fe_(2)O_(3)NDs/RGO)aerogel was facilely synthesized via excessive metal-ion-induced self-assembly and subsequent calcination route using Prussian blue/graphene oxide(PB/GO)composite aerogel as precursors.The deliberately designed a-Fe_(2)O_(3)NDs/RGO heterostructure offers a highly interconnected porous conductive network,large heterostructure interfacial area,and plenty of accessible active sites,greatly facilitating the electron transfer,electrolyte diffusion,and pseudocapacitive reactions.The obtained a-Fe_(2)O_(3)NDs/RGO aerogel could be used as flexible free-standing electrodes after mechanical compression,which exhibited a significantly enhanced specific capacitance of 347.4 F·g^(-1)at 1 A·g^(-1),extraordinary rate capability of 184 F·g^(-1)at 10 A·g^(-1),and decent cycling stability.With the as-prepared a-Fe_(2)O_(3)NDs/RGO as negative electrodes and the Co_(3)O_(4)NDs/RGO as positive electrodes,an all-solid-state asymmetric supercapacitor(a-Fe_(2)O_(3)NDs/RGO//Co_(3)O_(4)NDs/RGO asymmetric supercapacitor(ASC))was assembled,which delivered a high specific capacitance of 69.1 F·g^(-1)at 1 A·g^(-1)and an impressive energy density of 21.6 W·h·k·g^(-1)at 750 W·k·g^(-1),as well as good cycling stability with a capacity retention of 94.3%after 5,000 cycles.This work provides a promising avenue to design high-performance graphene-based composite electrodes and profound inspiration for developing advanced flexible energy-storage devices.展开更多
Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for ...Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for this most important forest region in China. Accordingly, the objective of this study is to develop a first comprehensive system for estimating the wood production for the five dominant forest types.Methods: Based on a network of 384 field plots and using the state-space approach, we develop a system of dynamic stand models, for each of the five main forest types. Four models were developed and evaluated, including a base model and three extended models which include the effects of dominant height and climate variables. The four models were fitted, and their predictive strengths were tested, using the "seemingly unrelated regression"(SUR) technique.Results: All three of the extended models increased the accuracy of the predictions at varying degrees for the five major natural forest types of northeastern China. The inclusion of dominant height and two climate factors(precipitation and temperature) in the base model resulted in the best performance for all the forest types. On average, the root mean square values were reduced by 13.0% when compared with the base model.Conclusion: Both dominant height and climate factors were important variables in estimating forest production. This study not only presents a new method for estimating forest production for a large region, but also explains regional differences in the effect of site productivity and climate.展开更多
Testbed technology is very important in the development of the Internet. Similar to the present internet, next generation internet also starts from testbed. There are two kinds of testbeds, testbed networks like CNGI-...Testbed technology is very important in the development of the Internet. Similar to the present internet, next generation internet also starts from testbed. There are two kinds of testbeds, testbed networks like CNGI-CERNET2, Internet2, Geant; testbed systems like PlanetLab, NS2. DRAGON-Lab can be viewed as both testbed network and testbed system. DRAGON-Lab is an independent AS （autonomous system） and connected to multiple real networks. On the other hand, DRAGON-Lab integrates many resources of its own, partners＇ and internet＇s, so as to provide open service. DRAGON-Lab has a large scale, provides open service, supports remote visualized experiments and programmable experiments. More details will be introduced in this paper.展开更多
Nanosized Fe^3＋ and Eu^3＋ codoped CeO2 solid solutions were synthesized via hydrothermal method. The crystalline structure of Ce1-x（Fe0.5Eu0.5）xO2-δx=0.00–0.30） solid solutions was carried out by the X-ray diff...Nanosized Fe^3＋ and Eu^3＋ codoped CeO2 solid solutions were synthesized via hydrothermal method. The crystalline structure of Ce1-x（Fe0.5Eu0.5）xO2-δx=0.00–0.30） solid solutions was carried out by the X-ray diffraction technique, and the spectrum features were identified by UV-Vis and Raman spectroscopy, respectively. It was observed that the cell parameters were first increased then decreased by increasing the doped ions content. The phase separation was detected when the dopant concentration reached to x=0.30. UV-Vis spectrum showed that the width of the band gap gradually reduced by increasing the doped content, and the solid solubility was determined to be x=0.20. The Raman technique displayed that the peak position of F2g mode gradually shifted to lower frequencies from 465 cm^–1 for x=0.00 to 440 cm^–1 for x=0.20. The catalytic effects of Ce1-x（Fe0.5Eu0.5）xO2-δsolid solutions on the electrochemistry properties of Mg2Ni/Ni were measured by mixing them together via ball milling technique. The electrochemical properties of the Mg_2Ni/Ni-Ce1-x（Fe0.5Eu0.5）xO2-δcomposites showed that the maximum discharge capability Cmax and the cycle stability were improved obviously. Meanwhile, the EIS characteristic also indicated that the doped solid solutions could enhance the rate of charge transfer on the surface of alloy. The catalytic effect of the solid solutions was speculated to rely on both the concentration of oxygen vacancies and the cell volumes of the solid solutions.展开更多
Photocatalytic overall water splitting(OWS)without using any sacrificial reagent to realize H_(2)and O_(2)production in the stoichiometric ratio of 2:1 is viewed as the“holy grail”in the field of solar fuel producti...Photocatalytic overall water splitting(OWS)without using any sacrificial reagent to realize H_(2)and O_(2)production in the stoichiometric ratio of 2:1 is viewed as the“holy grail”in the field of solar fuel production.Developing stable,low cost,and nontoxic photocatalysts that have satisfactory solar-tohydrogen conversion efficiency is of significance but challenging for realizing the large-scale use of this sustainable technology.Among various photocatalysts,graphitic carbon nitride(GCN)has shown great potential as an ideal candidate to fulfill the breakthrough in this dynamic research field due to its attractive physicochemical properties.Herein,for the first time,the state-ofthe-art research progress of GCN for photocatalytic OWS is reviewed.We first summarize the basic principle of photocatalytic OWS along with the advantages/challenges of GCN introduced.The strategies that have been used to modulate the OWS activity of GCN are then reviewed,including cocatalyst investigation,morphology modulation,atomic structure modification,crystallinity engineering,and heterostructure construction.Toward the end of the review,the concluding remarks and perspectives for the future development are presented,with our expectation to provide some new ideas for the design of advanced OWS photocatalysts.展开更多
Effective monitoring of the structural health of combined coal-rock under complex geological conditions by pressure stimulated currents(PSCs)has great potential for the understanding of dynamic disasters in undergroun...Effective monitoring of the structural health of combined coal-rock under complex geological conditions by pressure stimulated currents(PSCs)has great potential for the understanding of dynamic disasters in underground engineering.To reveal the effect of this way,the uniaxial compression experiments with PSC monitoring were conducted on three types of coal-rock combination samples with different strength combinations.The mechanism explanation of PSCs are investigated by resistivity test,atomic force microscopy(AFM)and computed tomography(CT)methods,and a PSC flow model based on progressive failure process is proposed.The influence of strength combinations on PSCs in the progressive failure process are emphasized.The results show the PSC responses between rock part,coal part and the two components are different,which are affected by multi-scale fracture characteristics and electrical properties.As the rock strength decreases,the progressive failure process changes obviously with the influence range of interface constraint effect decreasing,resulting in the different responses of PSC strength and direction in different parts to fracture behaviors.The PSC flow model is initially validated by the relationship between the accumulated charges of different parts.The results are expected to provide a new reference and method for mining design and roadway quality assessment.展开更多
Processing polyvinyl chloride(PVC)artificial material requires plasticizer that softens the PVC coating.Currently,utilizing unsaturated fatty acid methyl esters to obtain epoxidized fatty acid methyl ester(EFAME)bio-p...Processing polyvinyl chloride(PVC)artificial material requires plasticizer that softens the PVC coating.Currently,utilizing unsaturated fatty acid methyl esters to obtain epoxidized fatty acid methyl ester(EFAME)bio-plasticizers constitutes an environmentally responsible solution to substitute conventional ortho-phthalates that are endocrine disruptors or probable carcinogens.However,commercial EFAMEs,even with the highest epoxy value(ca.5.5-5.8%)so far,still suffer from fast leaching from the PVC matrix,burdening the environment and shortening lifespan of the artificial material.Here,we report a proof-of-principle demonstration of a new strategy to obtain migration-resistant EFAME that harnesses the midchain hydroxyl of methyl ricinoleate and covalently attachment of a pendant acetate ester.Despite a low epoxy value(3.0%),the engineered bio-plasticizer displays significantly suppressed migration in multiple scenarios compared with one conventional EFAME with much higher epoxy value(5.8%).Circumventing the limit confronting previous strategy that highlights the sole contribution of epoxy value to achievable migration resistance,the rationale herein may provide guidance for designing new EFAMEs with comparable performance to ortho-phthalates,thus bringing the old and oft-maligned PVC artificial material industry one step closer to sustainability.展开更多
Among plant metabolites,phenolamides,which are conjugates of hydroxycinnamic acid derivatives and polyamines,play important roles in plant adaptation to abiotic and biotic stresses.However,the molecular mechanisms und...Among plant metabolites,phenolamides,which are conjugates of hydroxycinnamic acid derivatives and polyamines,play important roles in plant adaptation to abiotic and biotic stresses.However,the molecular mechanisms underlying phenolamide metabolism and regulation as well as the effects of domestication and breeding on phenolamide diversity in tomato remain largely unclear.In this study,we performed a metabolite-based genome-wide association study and identified two biosynthetic gene clusters(BGC7 and BGC11)containing 12 genes involved in phenolamide metabolism,including four biosynthesis genes(two 4CL genes,one C3H gene,and one CPA gene),seven decoration genes(five AT genes and two UGT genes),and one transport protein gene(DTX29).Using gene co-expression network analysis we further discovered that SlMYB13 positively regulates the expression of two gene clusters,thereby promoting phenolamide accumulation.Genetic and physiological analyses showed that BGC7,BGC11 and SlMYB13 enhance drought tolerance by enhancing scavenging of reactive oxygen species and increasing abscisic acid content in tomato.Natural variation analysis suggested that BGC7,BGC11 and SlMYB13 were negatively selected during tomato domestication and improvement,leading to reduced phenolamide content and drought tolerance of cultivated tomato.Collectively,our study discovers a key mechanism of phenolamide biosynthesis and regulation in tomato and reveals that crop domestication and improvement shapes metabolic diversity to affect plant environmental adaptation.展开更多
As a promising graphene analogue,two-dimensional(2D)polymer nanosheets with unique 2D features,diversified topological structures and as well as tunable electronic properties,have received extensive attention in recen...As a promising graphene analogue,two-dimensional(2D)polymer nanosheets with unique 2D features,diversified topological structures and as well as tunable electronic properties,have received extensive attention in recent years.Here in this review,we summarized the recent research progress in the preparation methods of 2D polymer nanosheets,mainly including interfacial polymerization and solution polymerization.We also discussed the recent research advancements of 2D polymer nanosheets in the fields of energy storage and conversion applications,such as batteries,supercapacitors,electrocatalysis and photocatalysis.Finally,on the basis of their current development,we put forward the existing challenges and some personal perspectives.展开更多
基金the Clinical Research Fund of Southwest Hospital at Third Military Medical University (SWH2005A109)
文摘Objective： To study the efficacy and safety of autologous transplantation of bone marrow mesenchymal stem cells on diabetic patients with lower limb ischemia. Methods： Fifty Type 2 diabetic patients with lower limb ischemia were enrolled and randomized to either transplanted group or control group. Patients in both group received the same conventional treatment. Meanwhile, 20 ml bone marrow from each transplanted patient were collected, and the mesenchymal stem cells were separated by density gradient centrifugation and cultured in the medium with autologous serum. After three-weeks adherent culture in vitro, 7.32×10^8-5.61×10^9 mesenchymal stem cells were harvested and transplanted by multiple intramuscular and hypodermic injections into the impaired lower limbs. Results： At the end of 12-week follow-up, 5 patients were excluded from this study because of clinical worsening or failure of cell culture. Main ischemic symptoms, including rest pain and intermittent claudication, were improved significantly in transplanted patients. The ulcer healing rate of the transplanted group （1 5 of 18, 83.33%） was significantly higher than that of the control group （9 of 20, 45.00%, P=0.012）.The mean of resting ankle-brachial index （ABI） in transplanted group significantly was increased from 0.61±0.09 to 0.74±0.11 （P〈0.001）. Magnetic resonance angiography （MRA） demonstrated that there were more patients whose score of new vessels exceeded or equaled to 2 in the transplant patients （11 of 15） than in control patients （2 of 14, P=0.001）. Lower limb amputation rate was significantly lower in transplanted group than in the control group （P=0.040）. No adverse effects was observed in transplanted group. Conclusion： These results indicate that the autologous transplantation of bone marrow mesenchymal stem cells relieves critical lower limb ischemia and promotes ulcers healing in Type 2 diabetic patients.
基金supported by Youth Science Foundation of the National Natural Science Foundation of China(No.51104156)the Fundamental Research Funds for the Central Universities of China(No.2013QNB02)the 12th Five Year National Science and Technology Support Key Project of China(Nos. 2012BAK04B07-2 and 2012BAK09B01-04)
文摘The physical and mechanical change processes of coal and rock are closely related to energy transformation,and the destruction and failure of coal and rock is an instability phenomena driven by energy change.However,the energy change of large-scale coal rock in the mine site is hardly calculated accurately,making it difficult to monitor coal-rock systematic failure and collapse from the perspective of energy.By the energy dissipation EMR monitoring system,we studied the damage and failure of coal and rock with bursting liability from the energy dissipation point using the geophysical method-EMR,and explored the energy dissipation characteristics during uniaxial compression and their main influencing factors.The results show that under displacement-control loading mode,there are 2 types of energy dissipation trends for both coal and rock with bursting liability.The type Ⅰ trend is a steady increase one during the whole process,therein,the energy dissipation of rock samples is accelerated at the peak load.The type Ⅱ trend energy is a W-shaped fluctuating one containing 6 stages.Under load-control loading mode,there is one energy dissipation trend of shock downward-steady rise.Besides that,rock samples also present a trend of 4 stages.The energy dissipation characteristics of coal and rockduring loading failure process can be used as effective criteria to assess whether they are in a stable or destructive stage.The factors influencing energy dissipation in the loading failure process of coal and rock mainly include strength,homogeneity,and energy input efficiency.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB40010200 and XDA2009000004)the Program of Global Change and Mitigation+1 种基金Ministry of Science and Technology of China(2016YFA0600502)the National Natural Science Foundation of China(41877293,41672162,41977381,and 41472315)。
文摘Orbital-scale global climatic changes during the late Quaternary are dominated by high-latitude influenced~100,000-year global ice-age cycles and monsoon influenced~23,000-year low-latitude hydroclimate variations.However,the shortage of highly-resolved land temperature records remains a limiting factor for achieving a comprehensive understanding of long-term low-latitude terrestrial climatic changes.Here,we report paired mean annual air temperature(MAAT)and monsoon intensity proxy records over the past 88,000 years from Lake Tengchongqinghai in southwestern China.While summer monsoon intensity follows the~23,000-year precession beat found also in previous studies,we identify previously unrecognized warm periods at 88,000-71,000 and 45,000-22,000 years ago,with 2-3℃amplitudes that are close to our recorded full glacial-interglacial range.Using advanced transient climate simulations and comparing with forcing factors,we find that these warm periods in our MAAT record probably depends on local annual mean insolation,which is controlled by Earth’s~41,000-year obliquity cycles and is anti-phased to annual mean insolation at high latitudes.The coincidence of our identified warm periods and intervals of high-frequent dated archaeological evidence highlights the importance of temperature on anatomically modern humans in Asia during the last glacial stage.
基金supported by the National Basic Research Program of China(2010CB833406, 2010CB428902)Hong Kong Rearch Grants Council(HKU 703809P)+1 种基金supported by the Special Equipment Grant from the University Grants Committee of the Hong Kong Special Administrative Region,China(SEG_HKU01)the CAS/SAFEA International Partnership Program for Creative Research Teams(KZZD-EW-TZ03)
文摘Considerable efforts have been made to extend temperature records beyond the instrumental period through proxy reconstructions,in order to further understand the mechanisms of past climate variability.Yet,the global coverage of existing temperature records is still limited,especially for some key regions like the Tibetan Plateau and for earlier times including the Medieval Warm Period(MWP).Here we present decadally-resolved,alkenone-based,temperature records from two lakes on the northern Tibetan Plateau.Characterized by marked temperature variability,our records provide evidence that temperatures during the MWP were slightly higher than the modern period in this region.Further,our temperature reconstructions,within age uncertainty,can be well correlated with solar irradiance changes,suggesting a possible link between solar forcing and natural climate variability,at least on the northern Tibetan Plateau.
基金Supported by the National Natural Science Foundation of China(41705007 and 41575028)
文摘To evaluate the validity of cloud top height (CTH) retrievals from FY-4A, the first of China's next-generation geostationary meteorological satellite series, the retrievals are compared to those from Himawari-8, CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and Moderate Resolution Imaging Spectroradiometer (MODIS) operational products from August to October 2017. Regarding CTHs from CloudSat, CALIPSO, and MODIS as truth, the results show that the performance of FY-4A CTH retrievals is similar to that of Himawari-8. Both FY-4A and Himawari-8 retrieve reasonable CTH values for single-layer clouds, but perform poorly for multi-layer clouds. The mean bias error (MBE) shows that the mean value of FY-4A CTH retrievals is smaller than that of Himawari-8 for single-layer clouds but larger for multi-layer clouds. For ice crystal clouds, both FY-4A and Himawari-8 obtain the underestimated CTHs. However, there is a tendency for FY-4A and Himawari-8 to overestimate the CTH values of CloudSat and CALIPSO mainly for low level liquid water clouds. The temperature inversion near the tops of water clouds may result in an overestimation of CTHs. According to the MBE change with altitude, FY-4A and Himawari-8 overestimate the CTHs mainly for clouds below 3 km, and the overestimation is slightly more apparent in Himawari-8 data than that in FY-4A values. As the cloud optical thickness (COT) increases, the CTH bias of FY-4A CTH retrievals gradually decreases. Two typical cases are analyzed to illustrate the differences between different satellites' CTH retrievals in detail.
基金funded by the Major Program of Guangdong Basic and Applied Research(2019B030302006)supported by the National Natural Science Foundation of China(31930083,31901567,31901499,31801384)the China Postdoctoral Science Foundation(2019M662843,2019M652839,2019M662842)。
文摘Flowering time and stem growth habit determine inflorescence architecture in soybean, which in turn influences seed yield. Dt1, a homolog of Arabidopsis TERMINAL FLOWER 1(TFL1), is a major controller of stem growth habit, but its underlying molecular mechanisms remain unclear.Here, we demonstrate that Dt1 affects node number and plant height, as well as flowering time,in soybean under long-day conditions. The b ZIP transcription factor FDc1 physically interacts with Dt1, and the FDc1-Dt1 complex directly represses the expression of APETALA1(AP1). We propose that FT5 a inhibits Dt1 activity via a competitive interaction with FDc1 and directly upregulates AP1. Moreover, AP1 represses Dt1 expression by directly binding to the Dt1 promoter, suggesting that AP1 and Dt1 form a suppressive regulatory feedback loop to determine the fate of the shoot apical meristem. These findings provide novel insights into the roles of Dt1 and FT5 a in controlling the stem growth habit and flowering time in soybean, which determine the adaptability and grain yield of this important crop.
基金supported by the International Science and Technology Cooperation Program(No.2018KW-011)the National Key Research and Development Program of China(No.2016YFC0400706)+1 种基金the grant from "Young Outstanding Talents" in Universities of Shaanxi Provincesupport from the "Yanta Outstanding Youth Scholar" project from Xi'an University of Architecture and Technology(XAUAT)
文摘Wastewater treatment plants(WWTPs) are deemed reservoirs of antibiotic resistance genes(ARGs). Bacterial phylogeny can shape the resistome in activated sludge. However, the co-occurrence and interaction of ARGs abundance and bacterial communities in different WWTPs located at continental scales are still not comprehensively understood. Here, we applied quantitative PCR and Miseq sequence approaches to unveil the changing profiles of ARGs(sul1, sul2, tet W, tet Q, tet X), int I1 gene, and bacterial communities in 18 geographically distributed WWTPs. The results showed that the average relative abundance of sul1 and sul2 genes were 2.08 × 10^(-1) and 1.32 × 10^(-1) copies/16 S rRNA copies, respectively. The abundance of tet W gene was positively correlated with the Shannon diversity index(H′), while both studied sul genes had significant positive relationship with the int I1 gene. The highest average relative abundances of sul1, sul2, tet X, and int I1 genes were found in south region and oxidation ditch system. Network analysis found that 16 bacterial genera co-occurred with tet W gene. Co-occurrence patterns were revealed distinct community interactions between aerobic/anoxic/aerobic and oxidation ditch systems. The redundancy analysis model plot of the bacterial community composition clearly demonstrated that the sludge samples were significant differences among those from the different geographical areas,and the shifts in bacterial community composition were correlated with ARGs. Together,these findings from the present study will highlight the potential risks of ARGs and bacterial populations carrying these ARGs, and enable the development of suitable technique to control the dissemination of ARGs from WWTPs into aquatic environments.
基金supported by the National High-Tech Research Program of China(Grant Nos.2009AA122001 and 2009AA122004)
文摘Land surface water(LSW) is one of the most important resources for human survival and development, and it is also a main component of global water recycling. A full understanding of the spatial distribution of land surface water and a continuous measuring of its dynamics can support to diagnose the global ecosystem and environment. Based on the Global Land 30-water 2000 and Global Land 30-water 2010 products, this research analyzed the spatial distribution pattern and temporal fluctuation of land surface water under scale-levels of global, latitude and longitude, continents, and climate zones. The Global Land 30-water products were corrected the temporal inconsistency of original remotely sensed data using MODIS time-series data, and then calculated the indices such as water area, water ration and coefficient of spatial variation for further analysis. Results show that total water area of land surface is about 3.68 million km2(2010), and occupies 2.73% of land area. The spatial distribution of land surface water is extremely uneven and is gathered mainly in mid- to high-latitude area of the Northern Hemisphere and tropic area. The comparison of water ratio between 2000 and 2010 indicates the overall fluctuation is small but spatially differentiated. The Global Land 30-water products and the statistics provided the fundamental information for analyzing the spatial distribution pattern and temporal fluctuation of land surface water and diagnosing the global ecosystem and environment.
基金supported by the National Natural Science Foundation of China(Nos.51161015 and 50961009)the National High-Technology Research and Development Program of China(No.2011AA03A408)the Natural Science Foundation of Inner Mongolia,China(Nos.2011ZD10 and 2010ZD05)
文摘In order to ameliorate the electrochemical hydrogen storage performances of La-Mg–Ni system A_2B_7-type electrode alloys, the partial substitution of M (M = Zr, Pr) for La was performed. The melt spinning technology was used to fabricate the La_(0.75-x)M_xMg_0.25Ni_3.2Co_0.2Al_0.1 (M = Zr, Pr; x = 0, 0.1) electrode alloys. The influences of the melt spinning and substituting La with M (M = Zr, Pr) on the structures and the electrochemical hydrogen storage characteristics of the alloys were investigated. The analysis of XRD, SEM, and TEM reveals that the as-cast and spun alloys have a multiphase structure composed of two main phases (La, Mg)_2Ni_7 and LaNi_5 as well as a residual phase LaNi_2 . The as-spun (M = Pr) alloy displays an entire nanocrystalline structure, while an amorphous-like structure is detected in the as-spun (M = Zr) alloy, implying that the substitution of Zr for La facilitates the amorphous formation. The electrochemical measurements exhibit that the substitution of Pr for La clearly increases the discharge capacity of the alloys; however, the Zr substitution brings on an adverse impact. Meanwhile, the M (M = Zr, Pr) substitution significantly enhances its cycle stability. The melt spinning exerts an evident effect on the electrochemical performances of the alloys, whose discharge capacity and high rate discharge ability (HRD) first mount up and then fall with the growing spinning rate, whereas their cycle stabilities monotonously augment as the spinning rate increases.
基金supported by the InnovationGroup Major Research Project of Guizhou Province Education Department(No.Qianjiaohe KY[2017]043)the Science and Technology Support Project of Guizhou Province(2020-5012)+3 种基金the PhD Fund of Scientific Research Foundation of the Affiliated Hospital of ZunyiMedical University(2020-03)the National Nature Science Foundation of China(81660325)the Collaborative Innovation Center of the Chinese Ministry of Education(2020-39)the Master Fund of Scientific Research Foundation of the Affiliated Hospital of Zunyi Medical University(2016-35).
文摘Background:Schwann cell-like cells(SCLCs),differentiated from mesenchymal stem cells,have shown promising outcomes in the treatment of peripheral nerve injuries in preclinical studies.However,certain clinical obstacles limit their application.Hence,the primary aim of this study was to investigate the role of exosomes derived from SCLCs(SCLCs-exo)in peripheral nerve regeneration.Methods:SCLCs were differentiated from human amniotic mesenchymal stem cells(hAMSCs)in vitro and validated by immunofluorescence,real-time quantitative PCR and western blot analysis.Exosomes derived from hAMSCs(hAMSCs-exo)and SCLCs were isolated by ultracentrifugation and validated by nanoparticle tracking analysis,WB analysis and electron microscopy.A prefab-ricated nerve graft was used to deliver hAMSCs-exo or SCLCs-exo in an injured sciatic nerve rat model.The effects of hAMSCs-exo or SCLCs-exo on rat peripheral nerve injury(PNI)regeneration were determined based on the recovery of neurological function and histomorphometric variation.The effects of hAMSCs-exo or SCLCs-exo on Schwann cells were also determined via cell prolifer-ation and migration assessment.Results:SCLCs significantly expressed the Schwann cell markers glial fibrillary acidic protein and S100.Compared to hAMSCs-exo,SCLCs-exo significantly enhanced motor function recov-ery,attenuated gastrocnemius muscle atrophy and facilitated axonal regrowth,myelin forma-tion and angiogenesis in the rat model.Furthermore,hAMSCs-exo and SCLCs-exo were effi-ciently absorbed by Schwann cells.However,compared to hAMSCs-exo,SCLCs-exo signifi-cantly promoted the proliferation and migration of Schwann cells.SCLCs-exo also significantly upregulated the expression of a glial cell-derived neurotrophic factor,myelin positive regulators(SRY-box transcription factor 10,early growth response protein 2 and organic cation/carnitine transporter 6)and myelin proteins(myelin basic protein and myelin protein zero)in Schwann cells.Conclusions:These findings suggest that SCLCs-exo can more efficiently prom
基金the fund for post-doctoral program of Henan University to Z.H.C.(No.FJ3050A0670001)the National Natural Science Foundation of China(Nos.51672172,51872186).
文摘Constructing graphene-based heterostructures with large interfacial area is an efficient approach to enhance the electrochemical performance of supercapacitors but remains great challenges in their synthesis.Herein,a novel ultra-small amorphous Fe_(2)O_(3)nanodots/graphene heterostructure(a-Fe_(2)O_(3)NDs/RGO)aerogel was facilely synthesized via excessive metal-ion-induced self-assembly and subsequent calcination route using Prussian blue/graphene oxide(PB/GO)composite aerogel as precursors.The deliberately designed a-Fe_(2)O_(3)NDs/RGO heterostructure offers a highly interconnected porous conductive network,large heterostructure interfacial area,and plenty of accessible active sites,greatly facilitating the electron transfer,electrolyte diffusion,and pseudocapacitive reactions.The obtained a-Fe_(2)O_(3)NDs/RGO aerogel could be used as flexible free-standing electrodes after mechanical compression,which exhibited a significantly enhanced specific capacitance of 347.4 F·g^(-1)at 1 A·g^(-1),extraordinary rate capability of 184 F·g^(-1)at 10 A·g^(-1),and decent cycling stability.With the as-prepared a-Fe_(2)O_(3)NDs/RGO as negative electrodes and the Co_(3)O_(4)NDs/RGO as positive electrodes,an all-solid-state asymmetric supercapacitor(a-Fe_(2)O_(3)NDs/RGO//Co_(3)O_(4)NDs/RGO asymmetric supercapacitor(ASC))was assembled,which delivered a high specific capacitance of 69.1 F·g^(-1)at 1 A·g^(-1)and an impressive energy density of 21.6 W·h·k·g^(-1)at 750 W·k·g^(-1),as well as good cycling stability with a capacity retention of 94.3%after 5,000 cycles.This work provides a promising avenue to design high-performance graphene-based composite electrodes and profound inspiration for developing advanced flexible energy-storage devices.
基金supported by the Key Project of National Key Research and Development Plan(No.2017YFC0504104)the Program of National Natural Science Foundation of China(No.31670643)
文摘Background: There is a serious lack of experience regarding the productive potential of the natural forests in northeastern China, which severely limits the development of sustainable forest management strategies for this most important forest region in China. Accordingly, the objective of this study is to develop a first comprehensive system for estimating the wood production for the five dominant forest types.Methods: Based on a network of 384 field plots and using the state-space approach, we develop a system of dynamic stand models, for each of the five main forest types. Four models were developed and evaluated, including a base model and three extended models which include the effects of dominant height and climate variables. The four models were fitted, and their predictive strengths were tested, using the "seemingly unrelated regression"(SUR) technique.Results: All three of the extended models increased the accuracy of the predictions at varying degrees for the five major natural forest types of northeastern China. The inclusion of dominant height and two climate factors(precipitation and temperature) in the base model resulted in the best performance for all the forest types. On average, the root mean square values were reduced by 13.0% when compared with the base model.Conclusion: Both dominant height and climate factors were important variables in estimating forest production. This study not only presents a new method for estimating forest production for a large region, but also explains regional differences in the effect of site productivity and climate.
基金the National Basic Research Development Program of China (Grant No. 2003CB314807)the National High-Tech Research & Development Program of China (Grant No. 2005AA112130)
文摘Testbed technology is very important in the development of the Internet. Similar to the present internet, next generation internet also starts from testbed. There are two kinds of testbeds, testbed networks like CNGI-CERNET2, Internet2, Geant; testbed systems like PlanetLab, NS2. DRAGON-Lab can be viewed as both testbed network and testbed system. DRAGON-Lab is an independent AS （autonomous system） and connected to multiple real networks. On the other hand, DRAGON-Lab integrates many resources of its own, partners＇ and internet＇s, so as to provide open service. DRAGON-Lab has a large scale, provides open service, supports remote visualized experiments and programmable experiments. More details will be introduced in this paper.
基金Project supported by the National Natural Science Foundation of China(51501059)Talent Incubation Funding of School of Materials and Metallurgy and Inner Mongolia University of Science and Technology(2014CY012)
文摘Nanosized Fe^3＋ and Eu^3＋ codoped CeO2 solid solutions were synthesized via hydrothermal method. The crystalline structure of Ce1-x（Fe0.5Eu0.5）xO2-δx=0.00–0.30） solid solutions was carried out by the X-ray diffraction technique, and the spectrum features were identified by UV-Vis and Raman spectroscopy, respectively. It was observed that the cell parameters were first increased then decreased by increasing the doped ions content. The phase separation was detected when the dopant concentration reached to x=0.30. UV-Vis spectrum showed that the width of the band gap gradually reduced by increasing the doped content, and the solid solubility was determined to be x=0.20. The Raman technique displayed that the peak position of F2g mode gradually shifted to lower frequencies from 465 cm^–1 for x=0.00 to 440 cm^–1 for x=0.20. The catalytic effects of Ce1-x（Fe0.5Eu0.5）xO2-δsolid solutions on the electrochemistry properties of Mg2Ni/Ni were measured by mixing them together via ball milling technique. The electrochemical properties of the Mg_2Ni/Ni-Ce1-x（Fe0.5Eu0.5）xO2-δcomposites showed that the maximum discharge capability Cmax and the cycle stability were improved obviously. Meanwhile, the EIS characteristic also indicated that the doped solid solutions could enhance the rate of charge transfer on the surface of alloy. The catalytic effect of the solid solutions was speculated to rely on both the concentration of oxygen vacancies and the cell volumes of the solid solutions.
基金National Natural Science Foundation of China,Grant/Award Numbers:51902045,51904059Young Elite Scientist Sponsorship Program,Grant/Award Number:2019-2021QNRC+1 种基金Liao Ning Revitalization Talents Program,Grant/Award Number:XLYC1807123Fundamental Research Funds for the Central Universities,Grant/Award Numbers:N2002005,N182505036,N182503030。
文摘Photocatalytic overall water splitting(OWS)without using any sacrificial reagent to realize H_(2)and O_(2)production in the stoichiometric ratio of 2:1 is viewed as the“holy grail”in the field of solar fuel production.Developing stable,low cost,and nontoxic photocatalysts that have satisfactory solar-tohydrogen conversion efficiency is of significance but challenging for realizing the large-scale use of this sustainable technology.Among various photocatalysts,graphitic carbon nitride(GCN)has shown great potential as an ideal candidate to fulfill the breakthrough in this dynamic research field due to its attractive physicochemical properties.Herein,for the first time,the state-ofthe-art research progress of GCN for photocatalytic OWS is reviewed.We first summarize the basic principle of photocatalytic OWS along with the advantages/challenges of GCN introduced.The strategies that have been used to modulate the OWS activity of GCN are then reviewed,including cocatalyst investigation,morphology modulation,atomic structure modification,crystallinity engineering,and heterostructure construction.Toward the end of the review,the concluding remarks and perspectives for the future development are presented,with our expectation to provide some new ideas for the design of advanced OWS photocatalysts.
基金supported by National Key R&D Program of China(No.2022YFC3004705)the National Natural Science Foundation of China(Nos.52074280,52227901 and 52204249)National Natural Science Foundation of China Youth Fund(No.52104230).
文摘Effective monitoring of the structural health of combined coal-rock under complex geological conditions by pressure stimulated currents(PSCs)has great potential for the understanding of dynamic disasters in underground engineering.To reveal the effect of this way,the uniaxial compression experiments with PSC monitoring were conducted on three types of coal-rock combination samples with different strength combinations.The mechanism explanation of PSCs are investigated by resistivity test,atomic force microscopy(AFM)and computed tomography(CT)methods,and a PSC flow model based on progressive failure process is proposed.The influence of strength combinations on PSCs in the progressive failure process are emphasized.The results show the PSC responses between rock part,coal part and the two components are different,which are affected by multi-scale fracture characteristics and electrical properties.As the rock strength decreases,the progressive failure process changes obviously with the influence range of interface constraint effect decreasing,resulting in the different responses of PSC strength and direction in different parts to fracture behaviors.The PSC flow model is initially validated by the relationship between the accumulated charges of different parts.The results are expected to provide a new reference and method for mining design and roadway quality assessment.
基金financial support of this work by National Key Research and Development Program of China(2017YFB0308600)National Natural Science Foundation of China(21878196)Fundamental Research Funds for the Central Universities,China(20826041C4159).
文摘Processing polyvinyl chloride(PVC)artificial material requires plasticizer that softens the PVC coating.Currently,utilizing unsaturated fatty acid methyl esters to obtain epoxidized fatty acid methyl ester(EFAME)bio-plasticizers constitutes an environmentally responsible solution to substitute conventional ortho-phthalates that are endocrine disruptors or probable carcinogens.However,commercial EFAMEs,even with the highest epoxy value(ca.5.5-5.8%)so far,still suffer from fast leaching from the PVC matrix,burdening the environment and shortening lifespan of the artificial material.Here,we report a proof-of-principle demonstration of a new strategy to obtain migration-resistant EFAME that harnesses the midchain hydroxyl of methyl ricinoleate and covalently attachment of a pendant acetate ester.Despite a low epoxy value(3.0%),the engineered bio-plasticizer displays significantly suppressed migration in multiple scenarios compared with one conventional EFAME with much higher epoxy value(5.8%).Circumventing the limit confronting previous strategy that highlights the sole contribution of epoxy value to achievable migration resistance,the rationale herein may provide guidance for designing new EFAMEs with comparable performance to ortho-phthalates,thus bringing the old and oft-maligned PVC artificial material industry one step closer to sustainability.
基金supported by grants from the National Key Research and Development Program of China(2022YFF1001900)the Hainan Province Science and Technology Special Fund(no.ZDYF2022XDNY144)+4 种基金the Hainan Provincial Academician Innovation Platform Project(no.HD-YSZX-202004)the Young Elite Scientists Sponsorship Program by CAST(no.2019QNRC001)the Hainan University Startup Fund(no.KYQD(ZR)21025)the Collaborative Innovation Center of Nanfan and High-Efficiency Tropical Agriculture,Hainan University(no.XTCX2022NYB06)the Innovation Project of Postgraduates of Hainan Province(no.Qhyb2022-56).
文摘Among plant metabolites,phenolamides,which are conjugates of hydroxycinnamic acid derivatives and polyamines,play important roles in plant adaptation to abiotic and biotic stresses.However,the molecular mechanisms underlying phenolamide metabolism and regulation as well as the effects of domestication and breeding on phenolamide diversity in tomato remain largely unclear.In this study,we performed a metabolite-based genome-wide association study and identified two biosynthetic gene clusters(BGC7 and BGC11)containing 12 genes involved in phenolamide metabolism,including four biosynthesis genes(two 4CL genes,one C3H gene,and one CPA gene),seven decoration genes(five AT genes and two UGT genes),and one transport protein gene(DTX29).Using gene co-expression network analysis we further discovered that SlMYB13 positively regulates the expression of two gene clusters,thereby promoting phenolamide accumulation.Genetic and physiological analyses showed that BGC7,BGC11 and SlMYB13 enhance drought tolerance by enhancing scavenging of reactive oxygen species and increasing abscisic acid content in tomato.Natural variation analysis suggested that BGC7,BGC11 and SlMYB13 were negatively selected during tomato domestication and improvement,leading to reduced phenolamide content and drought tolerance of cultivated tomato.Collectively,our study discovers a key mechanism of phenolamide biosynthesis and regulation in tomato and reveals that crop domestication and improvement shapes metabolic diversity to affect plant environmental adaptation.
基金the National Natural Science Foundation of China(Nos.51873039 and 51673042)the Young Elite Scientist Sponsorship Program by CAST(No.2017QNRC001)the fund for post-doctoral program of Henan University to Z.H.C.(No.FJ3050A0670001).
文摘As a promising graphene analogue,two-dimensional(2D)polymer nanosheets with unique 2D features,diversified topological structures and as well as tunable electronic properties,have received extensive attention in recent years.Here in this review,we summarized the recent research progress in the preparation methods of 2D polymer nanosheets,mainly including interfacial polymerization and solution polymerization.We also discussed the recent research advancements of 2D polymer nanosheets in the fields of energy storage and conversion applications,such as batteries,supercapacitors,electrocatalysis and photocatalysis.Finally,on the basis of their current development,we put forward the existing challenges and some personal perspectives.
