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Vegetation-environment relationship in Pinus wallichiana forests of the Swat Hindukush range of Pakistan

Journal of Forestry Research 2020年第1期31卷 185-195页

作者： Inayat Ur Rahman Nasrullah Khan Kishwar Ali Siraj Ahmad Laboratory of Plant Ecology and Dendrochronology Department of BotanyUniversity of Malakand

Understanding the influence of environmental variables on the spatial distribution of ecological communities is essential to predict the response of vegetation to various environmental drivers.Ecological theory suggests that multiple environmental factors shape local species assemblages and should influence the various components of community structure and composition in different ways.This study aimed to classify Pinus wallichiana dominated forests in the Swat Hindukush range mountains to understand the relative influence of multiple environmental filters on its composition and structure.These forests represent the most typical of the species distribution in northern Pakistan and were not subjected to any phytosociological study.For this purpose,thirty forest stands,spanning a wide range of physical habitats were sampled using 10910 m plots and the importance value index was calculated.The floristic and environmental data were subjected to Ward’s agglomerative cluster analysis for objective classification and ordinated with NMS ordination for pattern description and testing the vegetation–environmental relationships.Three floristically and ecologically distinct communities were recognized along the topographic gradient(elevation,r=0.377;slope,r=0.5548)coupled with soil physical(clay,r=0.2782;silt,r=0.3225)and chemical properties(pH,r=0.4975;lime,r=3982).An elevation gradient of 100 m separated the low(Pinus wallichiana–Quercus dilatata community)and middle elevations forest stands(P.wallichiana pure population)from the highland population type(Pinus wallichiana–Cedrus deodara community).The floristics and structure of these forest types respond directly or indirectly to topographic and soil variables which were evidenced from the floristic composition,species richness,and community physiognomy.These characteristics of the communities changed from heterogenous,dense stands to sparsely dispersed conifers,broadleaved-evergreen,and deciduous vegetation types along the environmental gradients.We concluded that severa

关键词： Blue pine forests Classi cation ordination Ecological gradient Hindukush range mountains Species composition

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A model study of the effect of weather forcing on the ecology of a meromictic Siberian lake

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Journal of Oceanology and Limnology 2018年第6期36卷 2018-2032页

作者： Igor G.PROKOPKIN Egor S.ZADEREEV Institute of Biophysics SB RAS Krasnoyarsk Scientific Center660036AkademgorodokKrasnoyarskRussia Siberian Federal University 660079Svobodniiav.79KrasnoyarskRussia

We used a Lake Shira numerical model to estimate the response of the ecosystem of a saline meromictic lake to variations in weather parameters during the growing season. The sensitivity analysis of the model suggests that compared to other external(nutrient inflows) and internal(spring biomasses of food-web components) factors, weather parameters are among the most influential for both mixolimnetic(phyto-and zooplankton) and monimolimnetic(purple sulfur bacteria, sulfur reducing bacteria and hydrogen sulfide) food-web components. Calculations with different weather scenarios shows how changes in the water temperature and mixing depth af fect mixolimnetic and monimolimnetic food-web components and the depth of the oxic-anoxic interface in a meromictic lake. When weather forcing stimulates an increase in the biomass of food-web components in the mixolimnion, it produces cascading effects that lead to three results: 1) a higher content of detritus in the water column; 2) a higher content of hydrogen sulfide in the monimolimnion; 3) raising of the oxic-anoxic interface closer to the water-air surface. This cascading effect is complicated by the negative correlation between two light dependent primary producers located at diff erent depths—phytoplankton in the mixolimnion and purple sulfur bacteria at the oxic-anoxic interface. Thus, weather conditions that stimulate higher phytoplankton biomass are associated with a higher detritus content and lower biomass of purple sulfur bacteria, a higher content of hydrogen sulfide and a shallower oxic-anoxic interface. The same weather conditions(higher wind, lower cloud cover, and lower air temperature) promote a scenario of less stable thermal stratification. Thus, our calculations suggest that weather parameters during the summer season strongly control the mixing depth, water temperature and the mixolimnetic food web. An effect of biogeochemical and physical interactions on the depth of the oxicanoxic interface is also detectable. However, intra-and interannual climate and

关键词： meromictic lake numerical model weather forcing sensitivity analysis stratifi cation food web

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Inhibitive effect of loureirin B plus capsaicin on tetrodotoxin-resistant sodium channel

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Journal of Traditional Chinese Medicine 2018年第6期38卷 842-852页

作者： Chen Su Wan Ying Liu Xiangming Pan Xinxin College of Biomedical Engineering South-Central University for NationalitiesWuhan 430074China Hubei Key Laboratory of Medical Information Analysis and Tumor Diagnosis&Treatment Wuhan 430074China Key Laboratory of Cognitive Science of State Ethnic Affairs Commission Wuhan 430074China Gong Qing Institute of Science and Technology Jiujiang 332020China

OBJECTIVE: To investigate whether the effect of loureirin B plus capsaicin on tetrodotoxin-resistant(TTX-R) sodium channel.METHODS: By using whole-cell patch-clamp recordings, in acutely isolated dorsal root ganglion(DRG) neurons, the combined effects of loureirin B and capsaicin on TTX-R sodium channel were observed. Based on the data, the interaction between loureirin B and capsaicin in their modulation on TTX-R sodium channel was assessed.RESULTS: Loureirin B could not induce transient inward TRPV1 current. Capsazepine, a transient receptor potential vanilloid l(TRPV1) antagonist, could not attenuate the block of 0.64 mmol/L loureirin B on TTX-R sodium channel. There was no significant difference(P > 0.05) between IC_(50) of loureirin B(0.37 mmol/L) on TTX-R sodium channel in capsaicin-sensitive DRG neurons and that(0.38 mmol/L)in capsaicin-insensitive DRG neurons. However,there was a significant difference(P < 0.05) between the IC_(50) of capsaicin(0.28 μmol/L) on TTX-R sodium channel in capsaicin-sensitive DRG neurons and that(52.24 μmol/L) in capsaicin-insensitive DRG neurons. Four combinations composed of various concentrations of loureirin B and capsaicin could all inhibit TTX-R sodium currents but have different interactions between loureirin B and capsaicin.CONCLUSION: Loureirin B plus capsaicin could produce double blockage on TRPV1 and modulation on TTX-R sodium channel. The action of loureirin B onTTX-R sodium channel was independent ofTRPV1 but similar with that of capsaicin on TTX-R sodium channel in capsaicin-insensitive DRG neurons.

关键词： Loureirin B Capsaicin TRPV cation channels Spinal nerve roots Neurons Tetrodotoxin Sodium channels

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Ab initio study of the transition-metal carbene cations

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Science China Chemistry 1999年第1期42卷 83-88页

作者：李吉海冯大诚冯圣玉 Chemical College of Shandong University Ji’nan China

The geometries and bonding characteristics of the first-row transition-metal carbene cations MCH2+ were investigated by ab initio molecular orbital theory （HF/LANL2DZ）. All of MCH2+ are coplanar. In the closed shell structures the C bonds to M with double bonds; while in the open shell structures the partial double bonds are formed, because one of the σ and π orbitals is singly occupied. It is mainly the π-type overlap between the 2px orbital of C and 4px, 3dxz, orbitals of M+ that forms the π orbitals. The dissociation energies of C—M bond appear in periodic trend from Sc to Cu. Most of the calculated bond dissociation energies are close to the experimental ones.

关键词： transition-metal carbene cation geometry molecular orbital bond dissociation energy ab initio calculations.

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Kinetic effect in the size-control of CdS nanoparticles

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Science China Chemistry 1999年第6期42卷 631-638页

作者：杨建军张顺利张治军杜祖亮张军金振声 Laboratory of Lubrication and Functional Materials Henan University Kaifeng China Laboratory of Solid Lubrication Chinese Academy of Sciences Lanzhou China

A new method of size control for CdS nanoparticles, called common cation coprecipitation, is reported. In the course of coprecipitation, both CdS and CdSt2（cadmium stearate） formations are diffusion-controlled and their rates are quite different. The size of CdS nanoparticles depends on the ratio of initial concentrations of S2- to St- （stearate ion）. Characterized by UV-Vis absorption, XRD, TEM, fluorescence and XPS, the results obtained show that the coprecipitate is a composite, i. e. CdS particle inserts in the CdSt2 molecular layers to form a sandwich-like structure. The method reported for size control of CdS nanoparticles might be called kinetic self-assembling.

关键词： nanosized CdS cadmium stearate kinetic self-assembly common cation coprecipitation.

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Selective transport of Ag(Ⅰ) ion across a bulk liquid and polymer membranes incorporated with di-N-benzylated O_3N_2 donor macrocycles

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Chinese Chemical Letters 2010年第9期21卷 1111-1114页

作者： A.Nezhadali Department of Chemistry Payame Noor University(PNU)MashhadIran

The selective bulk liquid membrane and polymer membrane transports of Ag（Ⅰ） from an aqueous solution containing seven metal cations,Co（Ⅱ）,Ni（Ⅱ）,Cu（Ⅱ）,Zn（Ⅱ）,Ag（Ⅰ）,Cd（Ⅱ） and Pb（Ⅱ）,was studied.The source phases contained equimolar concentrations of the above-mentioned cations,with the source and receiving phases being buffered at pH 5.0 and 3.0,respectively. Ag（Ⅰ） ion transport occurred with a good efficiency from the aqueous source phases across the bulk liquid membrane and polymer membrane（derived from cellulose triacetate） containing ligand 1 as the ionophores,into the aqueous receiving phases.Clear transport selectivity for Ag（Ⅰ） was observed using ligand 1.There was no selectivity for the cations using ligand 2 in the both bulk liquid membrane and polymer membrane transports.

关键词： BLM PIM Transport Ag （I） cation Ligand

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Amphiphilic sodium alginate-vinyl acetate microparticles for drug delivery

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Journal of Oceanology and Limnology 2019年第3期37卷 855-862页

作者： YU Weiting ZHANG Demeng LIU Xiudong WANG Yunhong TONG Jun ZHANG Mengxue MA Xiaojun Affiliated Zhongshan Hospital of Dalian University Dalian 116001China Institute of Oceanology Chinese Academy of SciencesQingdao 266071China College of Environment and Chemical Engineering Dalian UniversityDalian Economic Technological Development ZoneDalian 116622China State Key Laboratory of Bioactive Seaweed Substances Qingdao Brightmoon Seaweed Group Co.Ltd.Qingdao 266400China Dalian Institute of Chemical Physics Chinese Academy of SciencesDalian 116023China

To overcome the fast or burst release of hydrophilic drugs from hydrophilic alginate-based carriers,hydrophobic molecule(vinyl acetate,VAc)was grafted on alginate(Alg),which was further used to prepare drug carriers.Amphiphilic Alg-g-PVAc hydrogel beads were firstly prepared by emulsification/internal gelation technique for the loading of bovine serum albumin(BSA).Then,chitosan was coated on the surface of beads to form novel amphiphilic Alg-g-PVAc/chitosan(Alg-g-PVAc/CS)microcapsules.The BSA-loading amphiphilic Alg-g-PVAc/chitosan(Alg-g-PVAc/CS)microcapsules display similar morphology and size to the hydrophilic alginate/chitosan(AC)microcapsules.However,the drug loading and loading efficiency of BSA in Alg-g-PVAc/CS microcapsules are higher,and the release rate of BSA from Alg-g-PVAc/CS microcapsules is slower.The results demonstrate that the introduction of hydrophobic PVAc on alginate can effectively help retard the release of BSA,and the higher degree of substitution is,the slower the release rate is.In addition,the complex membrane can also be adjusted to delay the release of BSA.As a whole,amphiphilic sodium alginate-vinyl acetate/CS microparticles could be developed for macromolecular drug delivery.

关键词： hydrophobic modifi cation sodium alginate-vinyl acetate amphiphilic Alg-g-PVAc/chitosan microcapsules drug delivery

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Recent progress in fluorescent and colorimetric sensors for the detection of ions and biomolecules

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Chinese Chemical Letters 2018年第11期29卷 1545-1559页

作者： Le Yu Yimu Qiao Lanxi Miao Yanqi He Ying Zhou College of Chemical Science and Technology Yunnan University

Optical sensors are widely used in the field of analytical sensing and optical imaging because of their high sensitivity, fast response time, and technical simplicity. The advantages of sensors lay in their non- invasive approach within biological tissues and inherent reliability in fluorescence imaging tests. In recent years the development of optical sensors for the sensing of ions, neutral molecules and especially tumor micro-environment-related parameters has been an active research area. This review focuses on recent contributions concerning fluorescent or colorimetric sensors and is organized according to their target classifications.

关键词： Anion cation Neutral molecules Tumor micro-environment Sensor Fluorescence

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Zwitterionic Hydroboranes Stabilized by β-Diimine Framework

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Chinese Journal of Chemistry 2017年第6期35卷 886-888页

作者： Jianfeng Li Hongfan Hu Chunming Cui State Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin 300071 China

Reaction of the N-heterocyclic borane [MeCCHC（CHe）（NAr）2]Btt （1, Ar=2,6-Me2C6H3） with B（C6F5）3 af- forded the zwitterionic hydroborane [MeCCHC（CHz）B（C6F5）3（NAr）2]BH, in which the β-methyl group can be d... 详细信息

关键词： borane cation zwitterion diimine deprotonation

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The study of terbium regenerated bacterirhodopsin

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Science China Chemistry 2005年第5期48卷 466-469页

作者： XU Bing ZHANG Yue HU Kunsheng Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China

The localization of Terbium (Tb3+) cations binding to deionized bacteriorhodopsin (bR) has been studied by using spectroscopic methods. It was found that adding Tb3+ cations to deionized bR affects the fluorescence lifetimes of tryptophan (Trp) in bR, the wavelength of fluo-rescence peak shifts “blue” and the peak value of fluorescence decreases. It was also found that adding one Tb3+ cation to deionized bR can restore the purple state from its blue state obviously. The measurements of absorbance, fluorescence and lifetime of fluorescence also show that when more than three Tb3+ cations are added, no further changes can be found. It is suggested that one Tb3+ specific binding site for the color-controlling is located on the exterior of the bR trimer structure to negatively charged lipids near Trp-10 and Trp-12. Three Tb3+ cations binding per bR is needed for the regenerated bR.

关键词： cation binding, fluorescence, bacteriorhodopsin, terbium.

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