聚氨基酸修饰的纳米二氧化硅的制备及在尼龙改性中的应用

基于氨基酸单体和纳米SiO_2粒子结构和功能的多样性,采用聚氨基酸来修饰纳米SiO_2粒子的研究有很大的发展空间。文中先用St9ber法制备纳米SiO_2粒子,再用3-氨基丙基三乙氧基硅烷(APTS)对其进行表面改性;并合成谷氨酸苄脂N-羧基酸酐(BLG-NCA),采用"Grafting from"法将其接枝到改性后的纳米SiO_2粒子上,最后得到聚谷氨酸修饰的纳米SiO_2核壳粒子。随着投料比的增加,其接枝聚氨基酸的壳的厚度增加,粒子之间出现粘连。将尼龙6与SiO_2及改性后的SiO_2熔融共混,得到复合材料。用透射电子显微镜、核磁共振氢谱、傅里叶变换红外光谱、热重分析表征了各阶段产物和聚合物的组成,并对复合材料的力学性能进行测试。实验结果表明,聚氨基酸能改善尼龙6与SiO_2的相容性,加入纯SiO_2使复合材料性能降低3%,而加入接枝二氧化硅后尼龙6的力学性能随着接枝粒子壳的厚度增加而增加,接枝厚度最大的粒子使拉伸性能提高了5%。

The Assessment of Global Surface Temperature Change from 1850s:The C-LSAT2.0 Ensemble and the CMST-Interim Datasets

Based on C-LSAT2.0,using high-and low-frequency components reconstruction methods,combined with observation constraint masking,a reconstructed C-LSAT2.0 with 756 ensemble members from the 1850s to 2018 has been developed.These ensemble versions have been merged with the ERSSTv5 ensemble dataset,and an upgraded version of the CMSTInterim dataset with 5°×5°resolution has been developed.The CMST-Interim dataset has significantly improved the coverage rate of global surface temperature data.After reconstruction,the data coverage before 1950 increased from 78%−81%of the original CMST to 81%−89%.The total coverage after 1955 reached about 93%,including more than 98%in the Northern Hemisphere and 81%−89%in the Southern Hemisphere.Through the reconstruction ensemble experiments with different parameters,a good basis is provided for more systematic uncertainty assessment of C-LSAT2.0 and CMSTInterim.In comparison with the original CMST,the global mean surface temperatures are estimated to be cooler in the second half of 19th century and warmer during the 21st century,which shows that the global warming trend is further amplified.The global warming trends are updated from 0.085±0.004℃(10 yr)^(–1)and 0.128±0.006℃(10 yr)^(–1)to 0.089±0.004℃(10 yr)^(–1)and 0.137±0.007℃(10 yr)^(–1),respectively,since the start and the second half of 20th century.

Numerical Simulation on Climate Effects of Freezing-Thawing Processes Using CCM3

A parameterization of soil freezing-thawing physics for use in the land-surface model of the National Center for Atmospheric Research(NCAR) Community Climate Model(CCM3) is developed and evaluated.The new parameterization scheme has improved the representation of physical processes in the existing land surface model.Numerical simulations using CCM3 with improved land-surface processes and with the original land-surface processes are compared against the NCEP reanalysis.It is found that the CCM3 version using the improved land surface model shows significant improvements in simulating precipitation in China during the summer season,the general circulation over East Asia,and wind fields over the Tibet Plateau.For the summer season,the improved model was able to better simulate the Indian summer monsoon components,including the mean northerly wind in the upper troposphere and mean southerly wind in the lower troposphere.

Characteristics of abrupt changes of snow cover and seasonal freeze-thaw layer in the Tibetan Plateau and their impacts on summer precipitation in China

In this paper, a variation series of snow cover and seasonal freeze-thaw layer from 1965 to 2004 on the Tibetan Plateau has been established by using the observation data from meteorological stations. The sliding T-test, M-K test and B-G algorithm are used to verify abrupt changes of snow cover and seasonal freeze-thaw layer in the Tibetan plateau. The results show that the snow cover has not undergone an abrupt change, but the seasonal freeze-thaw layer obviously witnessed a rapid degradation in 1987, with the frozen soil depth being reduced by about 15 cm. It is also found that when there ~s less snow in the plateau region, precipitation in South China and Southwest China increases. But when the frozen soil is deep, precipitation in most of China apparently decreases. Both snow cover and seasonal freeze-thaw layer on the plateau can be used to predict the summer precipitation in China. However, if the impacts of snow cover and seasonal freeze-thaw layer are used at the same time, the predictability of summer precipitation can be significantly improved. The significant correlation zone of snow is located in middle reaches of the Yangtze River covering the Hexi Corridor and northeastern Inner Mongolia, and the seasonal freeze-thaw layer exists in Mt. Nanling, northern Shannxi and northwestern part of North China. The significant correlation zone of simultaneous impacts of snow cover and seasonal freeze-thaw layer is larger than that of either snow cover or seasonal freeze-thaw layer. There are three significant correlation zones extending from north to south： the north zone spreads from Mr. Daxinganling to the Hexi Corridor, crossing northern Mt. Taihang and northern Shannxi; the central zone covers middle and lower reaches of the Yangtze River; and the south zone extends from Mt. Wuyi to Yunnan and Guizhou Plateau through Mt. Nanling.

Developed and Developing World Contributions to Climate System Change Based on Carbon Dioxide,Methane and Nitrous Oxide Emissions

One of the key issues in international climate negotiations is the formulation of targets for emissions reduction for all countries based on the principle of ＂common but differentiated responsibilities＂. This formulation depends primarily on the quantitative attribution of the responsibilities of developed and developing countries for historical climate change. Using the Commuity Earth System Model（CESM）, we estimate the responsibilities of developed countries and developing countries for climatic change from 1850 to 2005 using their carbon dioxide, methane and nitrous oxide emissions. The results indicate that developed countries contribute approximately 53%–61%, and developing countries approximately 39%–47%, to the increase in global air temperature, upper oceanic warming, sea-ice reduction in the NH, and permafrost degradation. In addition, the spatial heterogeneity of these changes from 1850 to 2005 is primarily attributed to the emissions of greenhouse gases（GHGs）in developed countries. Although uncertainties remain in the climate model and the external forcings used, GHG emissions in developed countries are the major contributor to the observed climate system changes in the 20 th century.

Coordinated Research on Orderly Human Activity to Cope with Global Climate Change—Our Thoughts and Recommendations

编辑笔记这是从二个中国科学家来的一封信到代·金博士， IPCC 的副主席工作组我。人的社会带了一个历史的步骤去地址气候变化问题。不管多么，怎么并且怎么理解气候变化到对气候的反应，变化将总是并且到处带争论和争论的各种各样的类型，因此影响即时迎着气候进行有序的人的活动的社会的步变化。在信，二个科学家上带上他们的想法和建议怎么在有序的人的活动执行协调研究应付全球气候变化。

Impacts of snow cover and frozen soil in the Tibetan Plateau on summer precipitation in China

This paper presents an analysis of the mechanisms and impacts of snow cover and frozen soil in the Tibetan Plateau on the sum- mer precipitation in China, using RegCM3 version 3.1 model simulations. Comparisons of simulations vs. observations show that RegCM3 well captures these impacts. Results indicate that in a more-snow year with deep frozen soil there will be more precipita- tion in the Yangtze River Basin and central Northwest China, western Inner Mongolia, and Xinjiang, but less precipitation in Northeast China, North China, South China, and most of Southwest China. In a less-snow year with deep frozen soil, however, there will be more precipitation in Northeast China, North China, and southern South China, but less precipitation in the Yangtze River Basin and in northern South China. Such differences may be attributed to different combination patterns of melting snow and thawing frozen soil on the Plateau, which may change soil moisture as well as cause differences in energy absorption in the phase change processes of snow cover and frozen soil. These factors may produce more surface sensible heat in more-snow years when the fi＇ozen soil is deep than when the frozen soil is shallow. The higher surface sensible heat may lead to a stronger updraft over the Plateau, eventually contributing to a stronger South Asia High and West Pacific Subtropical High. Due to different values of the wind fields at 850 hPa, a convergence zone will form over the Yangtze River Basin, which may produce more summer pre- cipitation in the basin area but less precipitation in North China and South China. However, because soil moisture depends on ice content, in less-snow years with deep frozen soil, the soil moisture will be higher. The combination of higher frozen soil moisture with latent heat absorption in the phase change process may generate less surface sensible heat and consequently a weaker updraft motion over the Plateau. As a result, both the South Asia High and the West Pacific Subtropical High will be weaker, hence caus- ing more summer precipitation in northern China but less in southem China.

Label-Free Virtual HER2 Immunohistochemical Staining of Breast Tissue using Deep Learning

The immunohistochemical(IHC)staining of the human epidermal growth factor receptor 2(HER2)biomarker is widely practiced in breast tissue analysis,preclinical studies,and diagnostic decisions,guiding cancer treatment and investigation of pathogenesis.HER2 staining demands laborious tissue treatment and chemical processing performed by a histotechnologist,which typically takes one day to prepare in a laboratory,increasing analysis time and associated costs.Here,we describe a deep learning-based virtual HER2 IHC staining method using a conditional generative adversarial network that is trained to rapidly transform autofluorescence microscopic images of unlabeled/label-free breast tissue sections into bright-field equivalent microscopic images,matching the standard HER2 IHC staining that is chemically performed on the same tissue sections.The efficacy of this virtual HER2 staining framework was demonstrated by quantitative analysis,in which three board-certified breast pathologists blindly graded the HER2 scores of virtually stained and immunohistochemically stained HER2 whole slide images(WSIs)to reveal that the HER2 scores determined by inspecting virtual IHC images are as accurate as their immunohistochemically stained counterparts.A second quantitative blinded study performed by the same diagnosticians further revealed that the virtually stained HER2 images exhibit a comparable staining quality in the level of nuclear detail,membrane clearness,and absence of staining artifacts with respect to their immunohistochemically stained counterparts.This virtual HER2 staining framework bypasses the costly,laborious,and time-consuming IHC staining procedures in laboratory and can be extended to other types of biomarkers to accelerate the IHC tissue staining used in life sciences and biomedical workflow.

破译pH值和金属离子编程的家蚕纺丝机制

Silk is one of the toughest fibrous materials known despite spun at ambient temperature and pressure with water as a solvent.It is a great challenge to reproduce high-performance artificial fibers comparable to natural silk by bionic for the incomplete understanding of silkworm spinning in vivo.Here,we found that amphipol and digitonin stabilized the structure of natural silk fibroin(NSF)by a large-scale screening in vitro,and then studied the close-to-native ultrastructure and hierarchical assembly of NSF in the silk gland lumen.Our study showed that NSF formed reversible flexible nanofibrils mainly composed of random coils with a sedimentation coefficient of 5.8 S and a diameter of about 4 nm,rather than a micellar or rod-like structure assembled by the aggregation of globular NSF molecules.Metal ions were required for NSF nanofibril formation.The successive p H decrease from posterior silk gland(PSG)to anterior silk gland(ASG)resulted in a gradual increase in NSF hydrophobicity,thus inducing the sol-gelation transition of NSF nanofibrils.NSF nanofibrils were randomly dispersed from PSG to ASG-1,and self-assembled into anisotropic herringbone patterns at ASG-2 near the spinneret ready for silkworm spinning.Our findings reveal the controlled self-assembly mechanism of the multi-scale hierarchical architecture of NSF from nanofibrils to herringbone patterns programmed by metal ions and p H gradient,which provides novel insights into the spinning mechanism of silk-secreting animals and bioinspired design of high-performance fibers.

Chronic Pulmonary Artery Stenosis:Time to Think as a Disease Entity

Chronic pulmonary artery stenosis(CPAS)is characterized by a reduction or complete obstruction of the cross-sectional area of the pulmonary artery owing to various causes.The condition exhibits similar pathophysiological progress,leading to pulmonary hypertension(PH),reduced physical endurance,right heart failure,and death.Although CPAS is often regarded as a subgroup of PH,it can manifest independently for an extended duration before the onset of PH and can significantly impact patient quality of life.It may therefore be more appropriate to consider PH as pathophysiological progression of CPAS,thereby recognizing CPAS as a distinct disease entity.

人-地系统模式耦合中数据时空匹配方法的新探索

人-地系统模式双向耦合的运行,存在着人-地数据时空尺度不相匹配的障碍.为使二者相匹配,在空间尺度上,提出通过经济模型将行政单元统计数据转变为网格数据的运行路径,并设计了“面积权重折算法”的数据转换方法,使经济系统的行政单元数据与地球系统模式的网格数据相匹配;在时间尺度上,将选取的不同时间尺度的经济统计数据整合到年际范围,使其与地球系统模式的时间步长尺度相一致.运用该方法分别对中国大陆和世界各国的人口、GDP、CO2排放等进行网格化处理,结果表明其特征与实际分布相一致.新方法结果可信度高,为人-地系统模式的双向耦合提供了可靠的变量运转的基础.

Global warming projections using the human–earth system model BNU-HESM1.0

Future climate change is usually projected by coupled earth system models under specific emission scenarios designed by integrated assessment models(IAMs),and this offline approach means there is no interaction between the coupled earth system models and the IAMs.This paper introduces a new method to design possible future emission scenarios and corresponding climate change, in which a simple economic and climate damage component is added to the coupled earth system model of Beijing Normal University(BNU-ESM). With the growth of population and technological expertise and the declining emission-to-output ratio described in the Dynamic Integrated Climate-Economy model, the projected carbon emission is 13.7 Gt C, resulting in a 2.4 °C warming by the end of the twenty-first century(2080–2099) compared with1980–1999. This paper also suggests the importance of the land and ocean carbon cycle in determining the CO2 concentration in the atmosphere. It is hoped that in the near future the next generation of coupled earth system models that include both the natural system and the social dimension will be developed.

19世纪80年代以来全球温度变暖趋势一致性进一步加强

升级了新的1850年以来的全球陆地气温数据集(C-LSAT2.0),结合美国NOAA/NCEI研发的ERSSTv5,将全球表面温度(CMST)观测数据集延长至1854~2019年,为全球气候变化研究提供了一个新的基准数据.对比发现,基于CMST的全球温度变化序列在1880年以前略高于其他几个全球序列,差异主要来源于采用不同海温数据所致,各个序列之间存在结构性不确定性;1880年之后, 5个全球表面温度观测序列的一致性非常高,并有显著一致的变暖趋势,具有高可靠性.基于C-LSAT2.0和CMST,对1880~2019年全球变暖趋势进行了估计,结果表明:近140年, 120年, 60年和40年陆地平均气温增暖趋势分别为:0.103±0.016, 0.115±0.020, 0.252±0.035和0.293±0.055°C/10 a;全球表面温度增暖趋势分别为:0.072±0.010, 0.084±0.011, 0.150±0.019和0.185±0.032°C/10 a.对1900~2018年全球年均温度EOF分析表明,前两个特征向量明显地反映了全球温度变化的主要模态:即全球一致升温模态和与太平洋年代际振荡(IPO)密切相关的模态.说明近120年全球温度变化主要由外部强迫(人类活动)和自然变率(IPO)控制.

Future changes in coverage of 1.5℃ and 2℃warming thresholds

The areas covered by 1.5 ℃ and 2.0 ℃ warming thresholds under RCP2.6, RCP4.5, and RCP8.5 were analyzed based on 22 CMIP5 models. More than 90% of the model runs are in agreement that by the end of the 21 st century, near-surface air temperature changes over ~5%(~2%), ~40%(~18%), and ~92%(~86%)of the globe will cross the 1.5 ℃(2.0 ℃) threshold under RCP2.6, RCP4.5, and RCP8.5, respectively. Under RCP8.5, nearly the whole of North America, Europe + Russia, Africa, and Asia–Russia will cross the 1.5 ℃(2.0 ℃) threshold in ~2050(~2060), while the coverage rates over South America and Oceania are ~80%(~75%) and ~50%(~30%), respectively. The threshold-onset time(TOT) for 2 ℃ warming is earliest over Europe + Russia and North America, followed by Africa, Asia–Russia, South America, and finally Oceania under the RCP4.5 and RCP8.5 scenarios. The TOT for 1.5 ℃ is ~10–30 years ahead of that for 2.0 ℃.

Influence of the carbon cycle on the attribution of responsibility for climate change

The carbon cycle is one of the fundamental climate change issues.Its long-term evolution largely affects the amplitude and trend of human-induced climate change,as well as the formulation and implementation of emission reduction policy and technology for stabilizing the atmospheric CO2concentration.Two earth system models incorporating the global carbon cycle,the Community Earth System Model and the Beijing Normal University-Earth System Model,were used to investigate the effect of the carbon cycle on the attribution of the historical responsibility for climate change.The simulations show that when compared with the criterion based on cumulative emissions,the developed(developing)countries’responsibility is reduced(increased)by 6%–10%using atmospheric CO2concentration as the criterion.This discrepancy is attributed to the fact that the developed world contributed approximately61%–68%(61%–64%)to the change in global oceanic(terrestrial)carbon sequestration for the period from 1850 to2005,whereas the developing world contributed approximately 32%–49%(36%–39%).Under a developed world emissions scenario,the relatively larger uptake of global carbon sinks reduced the developed countries’responsibility for carbon emissions but increased their responsibility for global ocean acidification(68%).In addition,the large emissions from the developed world reduced the efficiency of the global carbon sinks,which may affect the long-term carbon sequestration and exacerbate global warming in the future.Therefore,it is necessary to further consider the interaction between carbon emissions and the carbon cycle when formulating emission reduction policy.

SNORD126 promotes HCC and CRC cell growth by activating the PI3K-AKT pathway through FGFR2

小核仁的 RNA (snoRNA ) 机能障碍与癌症开发被联系了。SNORD126 是在它的主机基因的 introns 5-6 以内被编码的孤儿 C/D 框 snoRNA， cyclin 交往 B1 蛋白质 1 (CCNB1IP1 ) 。SNORD126 触发的联系癌症的分子的机制充分没被理解。这里，我们证明 SNORD126 高度在 hepatocellular 癌(HCC ) 被表示， colorectal 癌症(CRC ) 病人取样。SNORD126 在裸体老鼠增加了 Huh-7 和 SW480 细胞生长和 tumorigenicity。SNORD126 击倒禁止的 HepG2 和 LS174T 房间生长。我们证实 SNORD126 没与 miRNA 活动被处理成小 RNA。而且， SNORD126 没在 HCC 样品与 CCNB1IP1 显示出重要表示关联或调整 CCNB1IP1 表示。我们的基因表示侧面分析显示了基因经常印射到 PI3K-AKT 小径的那 SNORD126-upregulated。SNORD126 overexpression 增加了 phosphorylated AKT， GSK-3，和 p70S6K 的层次并且提高了成纤维细胞生长因素受体 2 (FGFR2 ) 表示。在 SNORD126-overexpressing Huh-7 细胞的 FGFR2 的调停 siRNA 的击倒或调停 AZD4547 的 inactivation 禁止了 AKT phosphorylation 并且压制了细胞生长。这些调查结果在癌症为 SNORD126 显示一个 oncogenic 角色并且作为一个治疗学的目标建议它的潜力。

Arctic Climate Changes Based on Historical Simulations(1900-2013) with the CAMS-CSM

The Chinese Academy of Meteorological Sciences Climate System Model(CAMS-CSM) is a newly developed global climate model that will participate in the Coupled Model Intercomparison Project phase 6. Based on historical simulations(1900-2013), we evaluate the model performance in simulating the observed characteristics of the Arctic climate system, which includes air temperature, precipitation, the Arctic Oscillation(AO), ocean temperature/salinity,the Atlantic meridional overturning circulation(AMOC), snow cover, and sea ice. The model-data comparisons indicate that the CAMS-CSM reproduces spatial patterns of climatological mean air temperature over the Arctic(60°-90°N) and a rapid warming trend from 1979 to 2013. However, the warming trend is overestimated south of the Arctic Circle, implying a subdued Arctic amplification. The distribution of climatological precipitation in the Arctic is broadly captured in the model, whereas it shows limited skills in depicting the overall increasing trend. The AO can be reproduced by the CAMS-CSM in terms of reasonable patterns and variability. Regarding the ocean simulation, the model underestimates the AMOC and zonally averaged ocean temperatures and salinity above a depth of 500 m, and it fails to reproduce the observed increasing trend in the upper ocean heat content in the Arctic. The largescale distribution of the snow cover extent(SCE) in the Northern Hemisphere and the overall decreasing trend in the spring SCE are captured by the CAMS-CSM, while the biased magnitudes exist. Due to the underestimation of the AMOC and the poor quantification of air–sea interaction, the CAMS-CSM overestimates regional sea ice and underestimates the observed decreasing trend in Arctic sea–ice area in September. Overall, the CAMS-CSM reproduces a climatological distribution of the Arctic climate system and general trends from 1979 to 2013 compared with the observations, but it shows limited skills in modeling local trends and interannual variability.

Research on Integrated Disaster Risk Governance in the Context of Global Environmental Change

To achieve sustainable development, understanding of the impact of global environmental change on natural resources and the frequency, intensity, and spatial-temporal patterns of all kinds of hazards should be advanced. In recent years, severe losses of human lives and property have been caused by very large-scale natural hazards all over the world, such as the freezing rain and snowstorm disaster in China in 2008, Typhoon Sidr in Bangladesh in 2007, and Hurricane Katrina in the United States in 2005. Strengthening the study on integrated disaster risk governance has become a pressing issue of sustainable development. Supported by the Chinese National Committee for the International Human Dimensions Program on Global Environmental Change(CNC-IHDP), its Working Group for Risk Governance proposed to the IHDP in 2006 to launch a new international research project on integrated risk governance(IRG) in the context of global environmental change. The IRG-Project was accepted by the IHDP Scientific Committee as a pilot science project in 2008 and was approved in 2010 as a full IHDP core science project under the Strategic Plan 2007–2015. The research foci of this international science project will be on the issues of science, technology, and management of integrated disaster risk governance based on case comparisons around the world, in order to advance the theories and methodologies of integrated disaster risk governance and to improve the practices of integrated disaster reduction in the real world.

Characteristics of pellets with immobilized activated sludge and its performance in increasing nitrification in sequencing batch reactors at low temperatures

Immobilized pellets obtained by means of entrapping activated sludge in waterborne polyurethane were successfully adapted in ammonium（NH4^＋–N）synthetic wastewater.Its physicochemical characteristics were determined using scanning electron microscope,pyrosequencing,and microelectrodes,and its influence on the nitrification process in sequencing batch reactors（SBRs）at low temperatures was evaluated.A large number of rod-shaped bacteria were observed on the surface of the immobilized pellet,in which Rudaea spp.（Xanthomonadaceae family）was an important bacterial component（23.44% of the total bacteria）.The oxygen uptake rate of immobilized pellets reached 240.83±15.59 mg O2/（L·hr）,and the oxygen was primarily consumed by the bacteria on the pellet surfaces（0–600μm）.The dosing of the pellets（30 m L/L）into an SBR significantly improved the nitrification efficiency at low temperatures of 7–11℃,achieving an average NH4^＋–N removal of 84.09%,which is higher than the removal of 67.46% observed for the control group.

A biased fairness assessment against developing countries

Since the adoption of the Paris Agreement, almost all countries have submitted their nationally determined contributions (NDCs) to the United Nations Framework Convention on Climate Change (UNFCCC) secretariat. Those submissions form the basis for the implementation of Paris Agreement. However, recent research [1] has shown that existing NDCs will not bring the world to the goal of limiting global temperature increase to below 2 °C above preindustrial levels, much less achieving the goal of limiting warming to 1.5 °C [2,3].