Analyses of stable isotopes(C,O,H)in tree rings are increasingly important cross-disciplinary programs.The rapid development in this field documented in an increasing number of publications requires a comprehensive re...Analyses of stable isotopes(C,O,H)in tree rings are increasingly important cross-disciplinary programs.The rapid development in this field documented in an increasing number of publications requires a comprehensive review.This study includes a bibliometric analysis-based review to better understand research trends in tree ring stable isotope research.Overall,1475 publications were selected from the Web of Science Core Collection for 1974-2023.The findings are that:(1)numbers of annual publications and citations increased since 1974.From 1974 to 1980,there were around two relevant publications per year.However,from 2020 to 2022,this rose sharply to 109 publications per year.Likewise,average article citations were less than four per year before 1990,but were around four per article per year after 2000;(2)the major subjects using tree ring stable isotopes include forestry,geosciences,and environmental sciences,contributing to 42.5%of the total during 1974-2023;(3)the top three most productive institutions are the Chinese Academy of Sciences(423),the Swiss Federal Institute for Forest,Snow and Landscape Research(227),and the University of Arizona(204).These achievements result from strong collaborations;(4)review papers,for example,(Dawson et al.,Annu Rev Ecol Syst 33:507-559,2002)and(McCarroll and Loader,Quat Sci Rev 23:771-801,2004),are among the most cited,with more than 1000 citations;(5)tree ring stable isotope studies mainly focus on climatology and ecology,with atmospheric CO_(2) one of the most popular topics.Since 2010,precipitation and drought have received increasing attention.Based on this analysis,the research stages,key findings,debated issues,limitations and direc-tions for future research are summarized.This study serves as an important attempt to understand the progress on the use of stable isotopes in tree rings,providing scientific guid-ance for young researchers in this field.展开更多
In conventional linear spectral mixture analysis model,a class is represented by a single endmember.However,the intra-class spectral variability is usually very large,which makes it difficult to represent a class,and ...In conventional linear spectral mixture analysis model,a class is represented by a single endmember.However,the intra-class spectral variability is usually very large,which makes it difficult to represent a class,and in this case,it leads to incorrect unmixing results. Some proposed algorithms play a positive role in overcoming the endmember variability,but there are shortcomings on computation intensive,unsatisfactory unmixing results and so on. Recently,sparse regression has been applied to unmixing,assuming each mixed pixel can be expressed as a linear combination of only a few spectra in a spectral library. It is essentially the same as multiple endmember spectral unmixing. OMP( orthogonal matching pursuit),a sparse reconstruction algorithm,has advantages of simple structure and high efficiency. However,it does not take into account the constraints of abundance non-negativity and abundance sum-to-one( ANC and ASC),leading to undesirable unmixing results. In order to solve these issues,this paper presents an improved OMP algorithm( fully constraint OMP,FOMP) for multiple endmember hyperspectral sparse unmixing. The proposed algorithm overcomes the shortcomings of OMP,and on the other hand,it solves the problem of endmember variability.The ANC and ASC constraints are firstly added into the OMP algorithm,and then the endmember set is refined by the relative increase in root-mean-square-error( RMSE) to avoid over-fitting,finally pixels are unmixed by their optimal endmember set. The simulated and real hyperspectral data experiments show that FOPM unmixing results are ideally comparable and abundance RMSE reduces much lower than OMP and simple spectral mixture analysis( s SMA),and has a strong anti-noise performance. It proves that multiple endmember spectral mixture analysis is more reasonable.展开更多
在本文中,我们首次报道了一种新型的硅酸盐负极材料NaTiSi2O6,由溶胶-凝胶法和固相烧结法合成而得。这种材料属于单斜晶系,空间群为C2/c。通过葡萄糖的高温裂解和碳化,NaTiSi2O6/C复合物被成功制备出来,其表面积为132 m^2·g^-1。在...在本文中,我们首次报道了一种新型的硅酸盐负极材料NaTiSi2O6,由溶胶-凝胶法和固相烧结法合成而得。这种材料属于单斜晶系,空间群为C2/c。通过葡萄糖的高温裂解和碳化,NaTiSi2O6/C复合物被成功制备出来,其表面积为132 m^2·g^-1。在0.1 A·g^-1的电流密度下其首圈放电和充电的比容量分别为542.9 m Ah·g^-1和266.6 m Ah·g^-1,首圈库伦效率为49.1%。在经过100圈循环后,其充电比容量为224.1 m Ah·g^-1,容量保持率为84.1%。原位X射线衍射测试表明,其充放电机理为嵌入反应。这使得NaTiSi2O6成为硅酸盐负极材料家族中新的一员。展开更多
To report a palliative and alternative surgical procedure, allogeneic sclera graft combined with autologous conjunctival flap (ASGACF), employing to repair the large emergent corneal perforation. The detail protocol o...To report a palliative and alternative surgical procedure, allogeneic sclera graft combined with autologous conjunctival flap (ASGACF), employing to repair the large emergent corneal perforation. The detail protocol of the surgical procedure was characterized and four representative cases were reviewed. An allogeneic sclera graft and recipient bed were prepared as the traditional penetrating keratoplasty (PK). And then sutured the sclera graft to the bed with 10-0 nylon suture and covered with a pedicled autologous conjunctival flap in half size. In the follow-up, the ASGACF repaired all of the corneal perforations and restored the integral walls of eyeballs, in spite of one who underwent a second surgery. This surgical procedure provided a palliative method to repair the large emergent corneal perforation while there is the lack of a corneal graft.展开更多
Long-term high resolution climate proxies are essential for understanding climate variability particularly,in regions such as the western Himalayas of northern Pakistan,where few long-term climate records are availabl...Long-term high resolution climate proxies are essential for understanding climate variability particularly,in regions such as the western Himalayas of northern Pakistan,where few long-term climate records are available.Using standard dendrochronological methods,an 1132-year(882 to 2013 C.E.)tree-ring chronology of Juniperus excelsa M.Bieb was established from the western Himalayas,northern Pakistan(WHNP).Tree growth was negatively and significantly(r=-0.65)correlated with the growing season(June-July)mean temperature,and positively and weakly(r=0.22)associated with precipitation.This inverse relationship of tree radial growth with temperature and positive association with precipitation demonstrated that forest growth is sensitive to high temperature related drought.Utilizing a reliable STD chronology and robust reconstruction model,a 928-year(1086 to 2013 C.E.)mean temperature reconstruction was developed for the WHNP using the substantial negative correlation between the summer temperature and standard tree ring-width chronology.According to statistical validation,the reconstruction accounted for 41.6% of the climatic variation for the period of 1956-2013 C.E.instrumental period.Individual extreme-warm periods occurred in 1093 C.E.(29.42℃)and extreme cold periods in 1088 C.E.(26.99℃)observed during the past 928 years.The reconstruction's multi-taper method(MTM)spectral analysis reveals significant(p<0.05)2-3-year and 63.8-year cycles.Since the 2-3-year cycle occurred within the range of ENSO variation,which indicates that ENSO had an impact on the regional temperature in our studied area.展开更多
A two-stage gas-coupled Stirling/pulse tube refrigerator(SPR),whose first and second stages respectively involve Stirling and pulse tube refrigeration cycles,is a very promising spaceborne refrigerator.The SPR has man...A two-stage gas-coupled Stirling/pulse tube refrigerator(SPR),whose first and second stages respectively involve Stirling and pulse tube refrigeration cycles,is a very promising spaceborne refrigerator.The SPR has many advantages,such as a compact structure,high reliability,and high performance,and is expected to become an essential refrigerator for space applications.In research regarding gas-coupled regenerative refrigerator,the energy flow distribution between the two stages,and optimal phase difference between the pressure wave and volume flow,are two critical parameters that could widely influence refrigerator performance.The effects of displacer displacement on the pressure wave,phase difference,acoustic power distribution,and inter-stage cooling capacity shift of the SPR have been investigated experimentally.Notably,to obtain the maximum first-stage cooling capacity,an inflection point in displacement exists.When the displacer displacement is larger than the inflection point,the cooling capacity could be distributed between the first and second stages.In the present study,an SPR was designed and manufactured to work between the liquid hydrogen and liquid oxygen temperatures,which can be used to cool small-scale zero boil-off systems and space detectors.Under appropriate displacer displacement,the SPR can reach a no-load cooling temperature of 15.4 K and obtain 2.6 W cooling capacity at 70 K plus 0.1 W cooling capacity at 20 K with 160 W compressor input electric power.展开更多
Bismuth vanadate(BiVO_(4),BVO)as a promising photoelectrode has been received great attention for photoelectrochemical(PEC)water splitting.However,the slow oxidation kinetics on the surface of BiVO_(4)limited the PEC ...Bismuth vanadate(BiVO_(4),BVO)as a promising photoelectrode has been received great attention for photoelectrochemical(PEC)water splitting.However,the slow oxidation kinetics on the surface of BiVO_(4)limited the PEC water splitting efficiency.Herein,nickel boride(Ni_(3)B,NB)nanoparticles,generally used in electrocatalytic field material,were modified on the surface of BiVO_(4)photoelectrode as an efficient cocatalyst to accelerate the oxygen evolution reaction.The as-prepared BVO-NB-5P photoelectrode exhibits a remarkable photocurrent density of 1.47 mA·cm^(−2)at 1.23 V versus the reversible hydrogen electrode(RHE)under air mass(AM)1.5 G illumination,which is about 2.8 times higher than the bare BiVO_(4)photoelectrode,and its water splitting rate is 11.3 times higher than bare BiVO_(4).The PEC studies reveal that the spin coated Ni_(3)B crystal cocatalyst could effectively reduce the water oxidation barrier,and improve the surface charge injection efficiency to 94%,which could boost the photogenerated holes reaction to enhance the PEC performance of BiVO_(4)photoelectrode.展开更多
Large tropical volcanic eruptions can cause short-term global cooling. However, little is known whether large tropical volcanic eruptions, like the one in Tambora/Indonesia in 1815, cause regional hydroclimatic anomal...Large tropical volcanic eruptions can cause short-term global cooling. However, little is known whether large tropical volcanic eruptions, like the one in Tambora/Indonesia in 1815, cause regional hydroclimatic anomalies. Using a tree-ring network of precisely dated Himalayan birch in the central Himalayas, we reconstructed variations in the regional pre-monsoon precipitation back to 1650 CE. A superposed epoch analysis indicates that the pre-monsoon regional droughts are associated with large tropical volcanic eruptions, appearing to have a strong influence on hydroclimatic conditions in the central Himalayas. In fact, the most severe drought since 1650 CE occurred after the Tambora eruption. These results suggest that dry conditions prior to monsoon in the central Himalayas were associated with explosive tropical volcanism. Prolonged La Ni?a events also correspond with persistent pre-monsoon droughts in the central Himalayas. Our results provide evidence that large tropical volcanic eruptions most likely induced severe droughts prior to monsoon in the central Himalayas.展开更多
Warming is significantly affecting ecosystems in dry-warm areas,such as the Middle East[1],but long-term climatic records are often scarce in these regions.One important proxy source of climate data is tree rings,whic...Warming is significantly affecting ecosystems in dry-warm areas,such as the Middle East[1],but long-term climatic records are often scarce in these regions.One important proxy source of climate data is tree rings,which have contributed to understanding climate changes over the past millennium[1].Under the PAGES2K framework[2],a tree-ring network of the Eurasian continent展开更多
Inflammatory responses of nucleus pulposus(NP)can induce imbalanced anabolism and catabolism of extracellular matrix,and the cytosolic dsDNA accumulation and STING-NF-κB pathway activation found in NP inflammation ar...Inflammatory responses of nucleus pulposus(NP)can induce imbalanced anabolism and catabolism of extracellular matrix,and the cytosolic dsDNA accumulation and STING-NF-κB pathway activation found in NP inflammation are considered as fairly important cause of intervertebral disc(IVD)degeneration.Herein,we constructed a siSTING delivery hydrogel of aldehyde hyaluronic acid(HA-CHO)and poly(amidoamine)PAMAM/siRNA complex to intervene the abnormal STING signal for IVD degeneration treatment,where the formation of dynamic Schiff base bonds in the system(siSTING@HPgel)was able to overcome the shortcomings such as low cellular uptake,short half-life,and rapid degradation of siRNA-based strategy.PAMAM not only formed complexes with siRNA to promote siRNA transfection,but also served as dynamic crosslinker to construct hydrogel,and the injectable and self-healing hydrogel efficiently and steadily silenced STING expression in NP cells.Finally,the siSTING@HPgel significantly eased IVD inflammation and slowed IVD degeneration by prolonging STING knockdown in puncture-induced IVD degeneration rat model,revealing that STING pathway was a therapeutic target for IVD degeneration and such novel hydrogel had great potential for being applied to many other diseases for gene delivery.展开更多
Incorporation of anions of Acid Red 114 dye (1,3-naphthalenedisulfonic acid, 8-[2-[3,3'-dimethyl-4'-[2-[4- [l(4-methylphenyl)sulfonyl]oxy] phenyl]diazenyl] [1,1'-biphenyl]-4-yl]diazenyl]-7-hydroxy-, disodium sal...Incorporation of anions of Acid Red 114 dye (1,3-naphthalenedisulfonic acid, 8-[2-[3,3'-dimethyl-4'-[2-[4- [l(4-methylphenyl)sulfonyl]oxy] phenyl]diazenyl] [1,1'-biphenyl]-4-yl]diazenyl]-7-hydroxy-, disodium salt) (denoted as NPDA) into ZnAl-layered double hydroxides (LDHs) has been carried out by an anion- exchange method in an effort to improve their thermal stability and light fastness. After intercalation of NPDA anions, the interlayer distance of the LDHs increases from 0.87 to 2.18 nm, confirming their incorporation into the interlayer galleries of the LDHs host. Infrared spectroscopy and thermogravimetric analysis revealed the presence of host-guest interactions between LDHs layers and NPDA anions. The thermal stability of NPDA and ZnAI-NPDA-LDHs was compared by thermogravimetric-differential ther- mal analysis, UV-visible spectroscopy and infrared spectroscopy. It was found that the thermal stability of NPDA anions was markedly improved by incorporation into the ZnA1-LDHs matrix, while the light fastness was also enhanced.展开更多
基金This study was supported by the National Natural Science Foundation of China(Grant Number:42007407,42022059)the Sino-German mobility program(M-0393)+1 种基金the Key Research Program of the Institute of Geology and Geophysics(CAS Grant IGGCAS-201905)the CAS Youth Interdisciplinary Team(JCTD-2021-05).
文摘Analyses of stable isotopes(C,O,H)in tree rings are increasingly important cross-disciplinary programs.The rapid development in this field documented in an increasing number of publications requires a comprehensive review.This study includes a bibliometric analysis-based review to better understand research trends in tree ring stable isotope research.Overall,1475 publications were selected from the Web of Science Core Collection for 1974-2023.The findings are that:(1)numbers of annual publications and citations increased since 1974.From 1974 to 1980,there were around two relevant publications per year.However,from 2020 to 2022,this rose sharply to 109 publications per year.Likewise,average article citations were less than four per year before 1990,but were around four per article per year after 2000;(2)the major subjects using tree ring stable isotopes include forestry,geosciences,and environmental sciences,contributing to 42.5%of the total during 1974-2023;(3)the top three most productive institutions are the Chinese Academy of Sciences(423),the Swiss Federal Institute for Forest,Snow and Landscape Research(227),and the University of Arizona(204).These achievements result from strong collaborations;(4)review papers,for example,(Dawson et al.,Annu Rev Ecol Syst 33:507-559,2002)and(McCarroll and Loader,Quat Sci Rev 23:771-801,2004),are among the most cited,with more than 1000 citations;(5)tree ring stable isotope studies mainly focus on climatology and ecology,with atmospheric CO_(2) one of the most popular topics.Since 2010,precipitation and drought have received increasing attention.Based on this analysis,the research stages,key findings,debated issues,limitations and direc-tions for future research are summarized.This study serves as an important attempt to understand the progress on the use of stable isotopes in tree rings,providing scientific guid-ance for young researchers in this field.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61405041,61571145)the Key Program of Heilongjiang Natural Science Foundation(Grant No.ZD201216)+2 种基金the Program Excellent Academic Leaders of Harbin(Grant No.RC2013XK009003)the China Postdoctoral Science Foundation(Grant No.2014M551221)the Heilongjiang Postdoctoral Science Found(Grant No.LBH-Z13057)
文摘In conventional linear spectral mixture analysis model,a class is represented by a single endmember.However,the intra-class spectral variability is usually very large,which makes it difficult to represent a class,and in this case,it leads to incorrect unmixing results. Some proposed algorithms play a positive role in overcoming the endmember variability,but there are shortcomings on computation intensive,unsatisfactory unmixing results and so on. Recently,sparse regression has been applied to unmixing,assuming each mixed pixel can be expressed as a linear combination of only a few spectra in a spectral library. It is essentially the same as multiple endmember spectral unmixing. OMP( orthogonal matching pursuit),a sparse reconstruction algorithm,has advantages of simple structure and high efficiency. However,it does not take into account the constraints of abundance non-negativity and abundance sum-to-one( ANC and ASC),leading to undesirable unmixing results. In order to solve these issues,this paper presents an improved OMP algorithm( fully constraint OMP,FOMP) for multiple endmember hyperspectral sparse unmixing. The proposed algorithm overcomes the shortcomings of OMP,and on the other hand,it solves the problem of endmember variability.The ANC and ASC constraints are firstly added into the OMP algorithm,and then the endmember set is refined by the relative increase in root-mean-square-error( RMSE) to avoid over-fitting,finally pixels are unmixed by their optimal endmember set. The simulated and real hyperspectral data experiments show that FOPM unmixing results are ideally comparable and abundance RMSE reduces much lower than OMP and simple spectral mixture analysis( s SMA),and has a strong anti-noise performance. It proves that multiple endmember spectral mixture analysis is more reasonable.
基金supported by the National Natural Science Foundation of China(21875045)the National Key Research and Development Program of China(2016YFB0901500)。
文摘在本文中,我们首次报道了一种新型的硅酸盐负极材料NaTiSi2O6,由溶胶-凝胶法和固相烧结法合成而得。这种材料属于单斜晶系,空间群为C2/c。通过葡萄糖的高温裂解和碳化,NaTiSi2O6/C复合物被成功制备出来,其表面积为132 m^2·g^-1。在0.1 A·g^-1的电流密度下其首圈放电和充电的比容量分别为542.9 m Ah·g^-1和266.6 m Ah·g^-1,首圈库伦效率为49.1%。在经过100圈循环后,其充电比容量为224.1 m Ah·g^-1,容量保持率为84.1%。原位X射线衍射测试表明,其充放电机理为嵌入反应。这使得NaTiSi2O6成为硅酸盐负极材料家族中新的一员。
基金This work was supported by grants from Shaanxi Provincial Natural Science Basic Research Program(NO.2016JM8017).
文摘To report a palliative and alternative surgical procedure, allogeneic sclera graft combined with autologous conjunctival flap (ASGACF), employing to repair the large emergent corneal perforation. The detail protocol of the surgical procedure was characterized and four representative cases were reviewed. An allogeneic sclera graft and recipient bed were prepared as the traditional penetrating keratoplasty (PK). And then sutured the sclera graft to the bed with 10-0 nylon suture and covered with a pedicled autologous conjunctival flap in half size. In the follow-up, the ASGACF repaired all of the corneal perforations and restored the integral walls of eyeballs, in spite of one who underwent a second surgery. This surgical procedure provided a palliative method to repair the large emergent corneal perforation while there is the lack of a corneal graft.
基金supported by the National Natural Science Foundation of China(Grant No.42007407)the Sino-German mobility program(M-0393)the China-Pakistan Joint Research Center on Earth Sciences(No.131551KYSB20200022).
文摘Long-term high resolution climate proxies are essential for understanding climate variability particularly,in regions such as the western Himalayas of northern Pakistan,where few long-term climate records are available.Using standard dendrochronological methods,an 1132-year(882 to 2013 C.E.)tree-ring chronology of Juniperus excelsa M.Bieb was established from the western Himalayas,northern Pakistan(WHNP).Tree growth was negatively and significantly(r=-0.65)correlated with the growing season(June-July)mean temperature,and positively and weakly(r=0.22)associated with precipitation.This inverse relationship of tree radial growth with temperature and positive association with precipitation demonstrated that forest growth is sensitive to high temperature related drought.Utilizing a reliable STD chronology and robust reconstruction model,a 928-year(1086 to 2013 C.E.)mean temperature reconstruction was developed for the WHNP using the substantial negative correlation between the summer temperature and standard tree ring-width chronology.According to statistical validation,the reconstruction accounted for 41.6% of the climatic variation for the period of 1956-2013 C.E.instrumental period.Individual extreme-warm periods occurred in 1093 C.E.(29.42℃)and extreme cold periods in 1088 C.E.(26.99℃)observed during the past 928 years.The reconstruction's multi-taper method(MTM)spectral analysis reveals significant(p<0.05)2-3-year and 63.8-year cycles.Since the 2-3-year cycle occurred within the range of ENSO variation,which indicates that ENSO had an impact on the regional temperature in our studied area.
基金supported by the Hundred Talents Program of the Chinese Academy of Sciences,the National Natural Science Foundation of China(Grant No.51806231)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB35000000,XDB35040102)。
文摘A two-stage gas-coupled Stirling/pulse tube refrigerator(SPR),whose first and second stages respectively involve Stirling and pulse tube refrigeration cycles,is a very promising spaceborne refrigerator.The SPR has many advantages,such as a compact structure,high reliability,and high performance,and is expected to become an essential refrigerator for space applications.In research regarding gas-coupled regenerative refrigerator,the energy flow distribution between the two stages,and optimal phase difference between the pressure wave and volume flow,are two critical parameters that could widely influence refrigerator performance.The effects of displacer displacement on the pressure wave,phase difference,acoustic power distribution,and inter-stage cooling capacity shift of the SPR have been investigated experimentally.Notably,to obtain the maximum first-stage cooling capacity,an inflection point in displacement exists.When the displacer displacement is larger than the inflection point,the cooling capacity could be distributed between the first and second stages.In the present study,an SPR was designed and manufactured to work between the liquid hydrogen and liquid oxygen temperatures,which can be used to cool small-scale zero boil-off systems and space detectors.Under appropriate displacer displacement,the SPR can reach a no-load cooling temperature of 15.4 K and obtain 2.6 W cooling capacity at 70 K plus 0.1 W cooling capacity at 20 K with 160 W compressor input electric power.
基金the Natural Science Foundation of Shandong Province(No.ZR2019EMQ001)Technology Project of Qingdao(No.22-3-7-cspz-9-nsh)the National Natural Science Foundation of China(No.21476262)is gratefully acknowledged.
文摘Bismuth vanadate(BiVO_(4),BVO)as a promising photoelectrode has been received great attention for photoelectrochemical(PEC)water splitting.However,the slow oxidation kinetics on the surface of BiVO_(4)limited the PEC water splitting efficiency.Herein,nickel boride(Ni_(3)B,NB)nanoparticles,generally used in electrocatalytic field material,were modified on the surface of BiVO_(4)photoelectrode as an efficient cocatalyst to accelerate the oxygen evolution reaction.The as-prepared BVO-NB-5P photoelectrode exhibits a remarkable photocurrent density of 1.47 mA·cm^(−2)at 1.23 V versus the reversible hydrogen electrode(RHE)under air mass(AM)1.5 G illumination,which is about 2.8 times higher than the bare BiVO_(4)photoelectrode,and its water splitting rate is 11.3 times higher than bare BiVO_(4).The PEC studies reveal that the spin coated Ni_(3)B crystal cocatalyst could effectively reduce the water oxidation barrier,and improve the surface charge injection efficiency to 94%,which could boost the photogenerated holes reaction to enhance the PEC performance of BiVO_(4)photoelectrode.
基金supported by the National Natural Science Foundation of China (41661144040)the Strategic Priority Research Program of Chinese Academy of Sciences (XDA20050101, XDA2006040103)+1 种基金Youth Innovation Promotion Association of Chinese Academy of Sciences, and the Open Research Fund of Key Laboratory of Tibetan Environmental Changes and Land Surface Processes, Chinese Academy of Sciencessupported by the Chinese Academy of Sciences President’s International Fellowship Initiative (2018PC0040)
文摘Large tropical volcanic eruptions can cause short-term global cooling. However, little is known whether large tropical volcanic eruptions, like the one in Tambora/Indonesia in 1815, cause regional hydroclimatic anomalies. Using a tree-ring network of precisely dated Himalayan birch in the central Himalayas, we reconstructed variations in the regional pre-monsoon precipitation back to 1650 CE. A superposed epoch analysis indicates that the pre-monsoon regional droughts are associated with large tropical volcanic eruptions, appearing to have a strong influence on hydroclimatic conditions in the central Himalayas. In fact, the most severe drought since 1650 CE occurred after the Tambora eruption. These results suggest that dry conditions prior to monsoon in the central Himalayas were associated with explosive tropical volcanism. Prolonged La Ni?a events also correspond with persistent pre-monsoon droughts in the central Himalayas. Our results provide evidence that large tropical volcanic eruptions most likely induced severe droughts prior to monsoon in the central Himalayas.
基金supported by the National Natural Science Foundation of China(42030508,41988101)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0301)+1 种基金funding from the European Research Council(ERC-SyG-2013-610028 IMBALANCE-P)funding from the project “Inside out”(#POIR.04.04.00-00-5F85/18-00)funded by the HOMING programme of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund。
基金supported by the International Partnership Program of Chinese Academy of Sciences(131C11KYSB20160061)the National Natural Science Foundation of China(41525001,41571201)+1 种基金Chinese Academy of Sciences President’s International Fellowship Initiative(2016VBC055)Karaj Branch Islamic Azad University for supporting Vilma Bayramzadeh’s sabbatical program in the Institute of Tibetan Plateau Research, Chinese Academy of Sciences
文摘Warming is significantly affecting ecosystems in dry-warm areas,such as the Middle East[1],but long-term climatic records are often scarce in these regions.One important proxy source of climate data is tree rings,which have contributed to understanding climate changes over the past millennium[1].Under the PAGES2K framework[2],a tree-ring network of the Eurasian continent
基金The study was sponsored by National Natural Science Foundation of China(81672150,51903050)Zhejiang medical and health science and technology project(2018KY117,2019ZD041)+1 种基金Natural Science Foundation of Zhejiang Province of China(LQ20H160053)New talent in medical field of Zhejiang Province,and the fundamental research funds for the central universities(2019QNA7027).
文摘Inflammatory responses of nucleus pulposus(NP)can induce imbalanced anabolism and catabolism of extracellular matrix,and the cytosolic dsDNA accumulation and STING-NF-κB pathway activation found in NP inflammation are considered as fairly important cause of intervertebral disc(IVD)degeneration.Herein,we constructed a siSTING delivery hydrogel of aldehyde hyaluronic acid(HA-CHO)and poly(amidoamine)PAMAM/siRNA complex to intervene the abnormal STING signal for IVD degeneration treatment,where the formation of dynamic Schiff base bonds in the system(siSTING@HPgel)was able to overcome the shortcomings such as low cellular uptake,short half-life,and rapid degradation of siRNA-based strategy.PAMAM not only formed complexes with siRNA to promote siRNA transfection,but also served as dynamic crosslinker to construct hydrogel,and the injectable and self-healing hydrogel efficiently and steadily silenced STING expression in NP cells.Finally,the siSTING@HPgel significantly eased IVD inflammation and slowed IVD degeneration by prolonging STING knockdown in puncture-induced IVD degeneration rat model,revealing that STING pathway was a therapeutic target for IVD degeneration and such novel hydrogel had great potential for being applied to many other diseases for gene delivery.
基金supported by National Natural Science Foundation of China
文摘Incorporation of anions of Acid Red 114 dye (1,3-naphthalenedisulfonic acid, 8-[2-[3,3'-dimethyl-4'-[2-[4- [l(4-methylphenyl)sulfonyl]oxy] phenyl]diazenyl] [1,1'-biphenyl]-4-yl]diazenyl]-7-hydroxy-, disodium salt) (denoted as NPDA) into ZnAl-layered double hydroxides (LDHs) has been carried out by an anion- exchange method in an effort to improve their thermal stability and light fastness. After intercalation of NPDA anions, the interlayer distance of the LDHs increases from 0.87 to 2.18 nm, confirming their incorporation into the interlayer galleries of the LDHs host. Infrared spectroscopy and thermogravimetric analysis revealed the presence of host-guest interactions between LDHs layers and NPDA anions. The thermal stability of NPDA and ZnAI-NPDA-LDHs was compared by thermogravimetric-differential ther- mal analysis, UV-visible spectroscopy and infrared spectroscopy. It was found that the thermal stability of NPDA anions was markedly improved by incorporation into the ZnA1-LDHs matrix, while the light fastness was also enhanced.