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Chinese Journal of polymer Science 2018年第11期36卷 1262-1268页

作者： Yan-Ling Xu Ao-Ting Qu Ru-Jiang Ma Ang Li Zhen-Kun Zhang Zhi-Qiang Shang Yao-Fang Zhang Lu-Xia Bu Ying-Li An State Key Laboratory of Medicinal Chemical Biology Key Laboratory of Functional Polymer Materials of Ministry of Education Institute of Polymer Chemistry Nankai University College of Basic Science Chemistry Experiment Teaching Center Tianjin Agricultural University

pH-responsive micelles with a biodegradable PLA core and a mixed PEG/PDPA shell were prepared by self-assembly of poly（ethylene glycol）-b-poly（lactic acid）（PEG-b-PLA） and poly（2-（diisopropylamino）ethyl methacrylate）-b-poly（lactic acid）（PDPA-b- PLA）. The micellization status with different pH and the enzyme degradation behavior were characterized by IH-NMR spectroscopy, dynamic light scattering measurement and zeta potential test. The pH turning point of PDPA block was determined to be in the range of 5.5-7.0. While the pH was above 7.0, the PDPA block collapsed onto the PLA core and could protect the PLA core from invasion of enzyme, as a result, the micelle exhibited a resistance to the enzymatic degradation.

关键词： pH-responsive Enzymatic degradation Poly(lactic acid)

Convenient preparation of charge-adaptive chitosan nanomedicines for extended blood circulation and accelerated endosomal escape

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Nano Research 2018年第8期11卷 4278-4292页

作者： Yapei Zhang Yingying Li Jinlong Ma Xinyu Wang Zhi Yuan Wei Wang Key Laboratory of Functional polymer Materials of the Ministry of Education Institute of Polymer Chemistry College of ChemistryHankai University Tianjin 300071 China Collaborative Innovation center of Chemical Science and Engineering Nankai University Tianiin 300071 China

A major impediment in the development of chitosan nanoparticles （CTS NPs） as effective drug delivery vesicles is their rapid clearance from blood and endosome entrapment. To overcome these problems, a convenient and promising template system was developed by decorating poly（methacrylic acid）（PMAA） to the surface of 10-hydroxy camptothecin （HCPT）-loaded CTS NPs （HCPT-CTS/ PMAA NPs）. The results show that the presence of negatively charged PMAA significantly elongated the blood circulation time of HCPT-CTS NPs from 12 to 24 h, and reduced the blood clearance （C1） from 30.57 to 6.72 mL/h in vivo. The calculated area under curve （AUC0-24h） and terminal elimination half-life （tl/2） of HCPT-CTS/PMAA NPs were 4.37-fold and 2.48-fold compared with those of HCPT-CTS NPs. Furthermore, the positively charged HCPT-CTS/PMAA NPs triggered by tumor acidic microenvironment （pH 6.5） result in a 453-fold higher cellular uptake than the negatively charged counterparts at pH 7.4. Additionally, HCPT-CTS/PMAA NPs have the ability to escape endosomal entrapment via ＂proton sponge effect＂ after incubation with HepG2 cells for 3 h at pH 6.5. Taken together, these findings open up a convenient, low-cost, but effective way to prepare HCPT-CTS/PMAA NPs as a candidate for developing vectors with enhanced long blood circulation and endosomal escape ability in future clinical experiments.

关键词： chitosanlpoly(methyl methacrylate) blood circulation charge reverse endosomal escape

Representativeness of Four Precipitation Observational Networks of China

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Acta meteorologica Sinica 2012年第4期26卷 454-466页

作者：任玉玉任国土 Laboratory for Climate studies National Climate CenterCMA

Four precipitation observational networks with varied station densities are maintained in China. They are： the Global Climate Observation System （GCOS） Surface Network （GSN）, the national Reference Climate Network （RCN）, the national-Basic Meteorological Network （BMN）, and the national Ordinary Meteorolog- ical Network （OMN）. The GSN, RCN, BMN, and the merged network of RCN and BMN （R＆B） have been widely used in climatology and climate change studies. In this paper, the impact of the usage of different networks on the precipitation climatology of China is evaluated by using the merged dataset of All Station Network （ASN） as a benchmark. The results show that all networks can capture the main features of the country average precipitation and its changing trends. The differences of average annual precipitation of the various networks from that of the ASN are less than 50 mm （≤ 10%）. All networks can successfully detect the rising trend of the average annual precipitation during 1961-2009, with the R＆B exhibiting the best representativeness （only 2.90% relative difference） and the GSN the poorest （39.77%）. As to the change trends of country average monthly precipitation, the networks can be ranked in descending order as R＆B （1.27%）, RCN （2.35%）, BMN （4.17%）, and GSN （7.46%）, and larger relative differences appear from August to November. The networks produce quite consistent spatial patterns of annual precipitation change trends, and all show an increasing trend of precipitation in Northwest and Southeast China, and a decreasing trend in North China, Northeast China, and parts of central China. However, the representativeness of the BMN and R＆B are better in annual and seasonal precipitation trends, in spite of the fact that they are still far from satisfactory. The relative differences of trends in some months and regions even reach more than 50%. The results also show that the representativeness of the RCN for country average precipitation is higher than that of the

关键词： climate stations observational network monitoring precipitation climatology precipitation change

On the Constant Metric Dimension of Generalized Petersen Graphs P(n,4)

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Acta Mathematica Sinica,English Series 2014年第7期30卷 1145-1160页

作者： Saba NAZ Muhammad SALMAN Usman ALI Imran JAVAID Syed Ahtsham-ul-Haq BOKHARY center for Advanced studies in Pure and Applied Mathematics Bahauddin Zakariya University

In this paper, we consider the family of generalized Petersen graphs P（n,4）. We prove that the metric dimension of P（n, 4） is 3 when n = 0 （mod 4）, and is 4 when n = 4k ＋ 3 （k is even）.For n = 1,2 （mod 4） and n = 4k ＋ 3 （k is odd）, we prove that the metric dimension of P（n,4） is bounded above by 4. This shows that each graph of the family of generalized Petersen graphs P（n, 4） has constant metric dimension.

关键词： Metric dimension constant metric dimension generalized Petersen graphs

Understanding lateral root formation,one cell at a time

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Molecular Plant 2021年第8期14卷 1229-1231页

作者： Anamarija Primc Alexis Maizel center for Organismal studies(COS) University of HeidelbergHeidelbergGermany

Formation of lateral roots shapes the architecture of plant root systems and con tributes to their *** Arabidopsis,lateral roots follow a well-described sequenee of events that lead to the emergence of a new root complete with its own meristem and a set of tissue and cell types very similar to the ones found in the primary *** are the different cell types established?In a recent study,Serrano-Ron et al.(2021)used single-cell RNA sequencing(scRNA-seq)to profile the diversity of cell types in the forming lateral roots and revealed a hitherto unknown role for camalexins in controlling lateral root patterning.

关键词： roots Arabidopsis cell

Simulations of the Tropical Intraseasonal Oscillation by the Atmospheric General Circulation Model of the Beijing Climate center

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Acta meteorologica Sinica 2010年第5期24卷 571-583页

作者：董敏吴统文王在志张芳 Laboratory for Climate studies of CMA National Climate Center

The performance of BCC （Beijing Climate center） AGCM 2.0.1 （Atmospheric General Circulation Model version 2.0.1） in simulating the tropical intraseasonal oscillation （TIO） is examined in this *** simulations are validated against observation and compared with the NCAR CAM3 （Community Atmosphere Model version 3） *** BCC AGCM2.0.1 is developed based on the original BCC AGCM （version 1） and NCAR *** reference atmosphere and reference pressure are introduced into the ***,the original prognostic variables of temperature and surface pressure become their departures from the reference atmosphere.A new Zhang-McFarlane convective parameterization scheme is incorporated into the model with a few *** modifications include those in the boundary layer process and snow cover *** simulations are run for 52 yr from 1949 to 2001 under the lower boundary conditions of observed monthly *** TIOs from the model are *** comparison shows that the NCAR CAM3 has a poor ability in simulating the *** simulated strength of the TIO is very *** energy of the eastward moving waves is similar to that of the westward moving waves in *** in observation the former is much larger than the *** seasonal variation and spatial distribution of the TIO produced by CAM3 are also much different from the *** ability of the BCC AGCM2.0.1 in simulating the TIO is significantly *** simulated TIO is *** strength of the TIO produced by the BCC AGCM2.0.1 is close to the *** energy of eastward *** is much stronger than that of the westward moving waves,which is consistent with the *** is no significant difference in the seasonal variation and spatial distribution of the TIO between the BCC model simulation and the *** general,the BCC model performs better than CAM3 in simulating the TIO.

关键词： Beijing Climate center (BCC) atmospheric general circulation model (AGCM) tropical intraseasonal oscillation (TIO) simulation study

On a New Three-Component Camassa Holm Equation with Peakons

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Communications in Theoretical Physics 2010年第2期53卷 223-230页

作者：屈长征付英 center for Nonlinear studies Northwest University Department of Mathematics Northwest University

A new three-component Camassa-Holm equation is introduced. This system is endowed with a structuresimilar to the Camassa-Holm equation. It has peakon solitons and conserves H^1-norm conservation law.

关键词： multi-component Camassa-Holm equation peakon solitons H^1-norm conservation law

Ocean Data Assimilation Using Intermittent Analyses and Continuous Model Error Correction

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Advances in Atmospheric Sciences 2002年第6期19卷 965-992页

作者： BohuaHuang JamesL.KinterIII PaulS.Schopf center for Ocean-Land-Atmosphere studies Institute of Global Environment and Society

A new data insertion approach is applied to the Derber and Rosati ocean data assimilation (ODA) system, a system that uses a variational scheme to analyze ocean temperature and provide ocean model corrections continuously. Utilizing the same analysis component as the original system, the new approach conducts analyses to derive model corrections intermittently at once-daily intervals. A technique similar to the Incremental Analysis Update (IAU) method of Bloom et al. is applied to incorporate the corrections into the model gradually and continuously. This approach is computationally more economical than the original.A 13-year global ocean analysis from 1986 to 1998 is produced using this new approach and compared with an analysis based on the original one. An examination of both analyses in the tropical Pacific Ocean shows that they have qualitatively similar annual and interannual temperature variability. However, the new approach produces smoother monthly analyses. Moreover, compared to the independent

关键词： data assimilation ocean general circulation model ocean current temperature profiles sea surface temperature

Resolvability in Circulant Graphs

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Acta Mathematica Sinica,English Series 2012年第9期28卷 1851-1864页

作者： Muhammad SALMAN Imran JAVAID Muhammad Anwar CHAUDHRY center for Advanced studies in Pure and Applied Mathematics Bahauddin Zakariya University

A set W of the vertices of a connected graph G is called a resolving set for G if for every two distinct vertices u, v E V（G） there is a vertex w E W such that d（u, w） ≠ d（v, w）. A resolving set of minimum cardinality is called a metric basis for G and the number of vertices in a metric basis is called the metric dimension of G, denoted by dim（G）. For a vertex u of G and a subset S of V（G）, the distance between u and S is the number minses d（u,s）. A k-partition II = {$1,$2,..., Sk} of V（G） is called a resolving partition if for every two distinct vertices u, v E V（G） there is a set Si in H such that d（u, Si） ≠ d（v, Si）. The minimum k for which there is a resolving k-partition of V（G） is called the partition dimension of G, denoted by pd（G）. The circulant graph is a graph with vertex set Zn, an additive group of integers modulo n, and two vertices labeled i and j adjacent if and only if i - j （rood n） E C, where C C Zn has the property that C = -C and 0 ￠ C. The circulant graph is denoted by Xn,△ where A = ｜C｜. In this paper, we study the metric dimension of a family of circulant graphs Xn,3 with connection set C = {1, 3, n - 1} and prove that dim（Xn,3） is independent of choice of n by showing that dim（Xn,a） = {3 for all n ≡0 （mod 4）,4 for all n≡2 （mod4）.We also study the partition dimension of a family of circulant graphs Xm,4 with connection set C = {±1, ±2} and prove that pd（Xn,4） is independent of choice of n and show that pd（X5,4） = 5 and pd（Xn,a） ={ 3 for all odd n≥9,4 for all even n≥6 and n=7.

关键词： Circulant graphs metric dimension partition dimension

Fouling and cleaning of membrane——a literature review

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Journal of Environmental Sciences 2000年第2期12卷 116-126页

作者： Zhao, Yan-Jun Wu, Kai-Fen Wang, Zheng-Jun Zhao, Liang Li, Shu-Shen polymer Membrane Division Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Membrane fouling curtails severely the economical and practical implementation of membrane process. The fundamental principles and mechanisms of membrane fouling as well as factors affecting fouling have been summarized in this paper. It also has covered three fouling resistance models and four kinds of approaches to improve membrane performance. Membrane cleaning methods are also discussed including physical, chemical, physico\|chemical and biological methods. In the four groups of basic cleaning methods, biological cleaning has considerable advantages and potentials. Extensive research work should be carried out further to explore and develop new ideas and techniques in the field of membrane cleaning and restoration.

关键词： membrane fouling cleaning CLC number: X703 Document code: A