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Localization of calmodulin and calmodulin-like protein and their functions in biomineralization in P. fucata

Progress in Natural science:Materials International 2008年第4期18卷 405-412页

作者： Zi Fang a, Zhenguang Yan a, Shuo Li a, Qin Wang a, Weizhong Cao a, Guangrui Xu a, Xunhao Xiong a, Liping Xie a,b, Rongqing Zhang a,b, a Institute of Marine Biotechnology, Department of Biological science and Biotechnology, tsinghua university, beij.ng 100084, china b Protein science laboratory of the Ministry of Education, tsinghua university, beij.ng 100084, china Institute of Marine Biotechnology Department of Biological Science and Biotechnology Tsinghua University Beijing 100084 China Protein science laboratory of the Ministry of Education Tsinghua University Beijing 100084 China

Calmodulin (CaM) and calmodulin-like protein (CaLP) are two proteins involved in biomineralization. Their localizations in Pinct- ada fucata mantle epithelia were studied by Western blot (WB) analysis of the nuclear/cytosol fraction of primary cultured P. fucata mantle cells and immunogold electron microscopy. The results showed a completely different distribution of these two proteins at the subcellular level. CaM was distributed throughout both the nucleus and cytoplasm of the mantle epithelium but CaLP was distributed only in the cytoplasm. The functions of these two proteins in biomineralization were investigated by shell regeneration. During this pro- cess, the expressions of CaM and CaLP were greatly enhanced in different organelles of the mantle epithelium. Overexpression of these two proteins and a mutant of calmodulin-like protein (M-CaLP) that lacks an extra C-terminal tail in MC3T3-E1 promoted the mRNA expression of osteopontin, a biomineralization marker for osteoblasts. All of the results indicated that CaM and CaLP have completely different distributions in the mantle epithelium and affect the biomineralization process at different levels. The extra C-terminal tail of CaLP is important for its functions in biomineralization in P. fucata.

关键词： Pinctada fucata Calmodulin Calmodulin-like protein Immunogold electron microscopy

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Sediment pollution and its effect on fish through food chain in the Yangtze River

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International Journal of Sediment Research 2008年第4期23卷 338-347页

Suspended sediment adsorbs pollutants from flowing water in rivers and deposits onto the bed. However, the pollutants accumulated in the river bed sediment may affect the bio-community through food chain for a long period of time. To study the problem the concentration of heavy metals (Cr, Cd, Hg, Cu, Fe, Zn, Pb and As) in water, sediment, and fish/invertebrate were investigated in the middle and lower reaches of the Yangtze River during 2006-2007. The concentrations of heavy metals were 100-10,000 times higher in the sediment than in the water. Benthic invertebrates had relatively high concentrations of heavy metals in their tissues due to their proximity to contaminated sediments. Benthic invertivore fish had moderately high concentrations of heavy metals whereas phytoplanktivore fish, such as the silver carp, accumulated the lowest concentration of heavy metals. The concentrations of Cu, Zn, and Fe were higher than Hg, Pb, Cd, Cr, and As in the tissue samples. The concentration of heavy metals was lower in the river sediments than in the lake sediments. Conversely, the concentration of heavy metals was higher in river water than in lake water. While a pollution event into a water body is often transitory, the effects of the pollutants may be long-lived due to their tendency to be absorbed in the sediments and then released into the food chain. The heavy metals were concentrated in the following order: bottom material > demersal fish and benthic fauna > middle-lower layer fish > upper-middle layer fish > water.

关键词： Sediment pollution Heavy metal Fish Invertebrate Yangtze River

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Investigation of heavy metal partitioning influenced by flue gas moisture and chlorine content during waste incineration

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Journal of Environmental sciences 2010年第5期22卷 760-768页

作者： Qinghai Li,Aihong Meng,Jinyan Jia,Yanguo Zhang Department of Thermal Engineering,Key laboratory for Thermal science and Power Engineering of the Ministry of Education of china,tsinghua university,beij.ng 100084,china. [a] Department of Thermal Engineering Key Laboratory for Thermal Science Power Engineering of the Ministry of Education of china Tsinghua University Beijing 100084 China

The impact of moisture on the partitioning of the heavy metals including Pb,Zn,Cu and Cd in municipal solid waste （MSW） was studied in a laboratory tubular furnace.A thermodynamic investigation using CHEMKIN software was performed to compare the experimental *** waste,representative of typical MSW with and without chlorine compounds,was burned at the background temperature of 700 and 950°C,*** the absence of chlorine,the moisture content has no evident effect on the volatility of Pb,Zn and Cu at either 700 or 950°C,however,as flue gas moisture increasing the Cd distribution in the bottom ash increased at 700°C and reduced at 950°C,*** the presence of chlorine,the flue gas moisture reduced the volatility of Pb,Zn and Cu due to the transformation of the more volatile metal chlorides into less volatile metal oxides,and the reduction became significant as chlorine content *** Cd,the chlorine promotes its volatility through the formation of more volatile CdCl *** a result,the increased moisture content increases the Pb,Zn,Cu and Cd concentrations in the bottom ash,which limits the utilization of the bottom ash as a construction ***,in order to accumulate heavy metals into the fly ash,MSW should be dried before incineration.

关键词： heavy metals partitioning moisture chlorine municipal solid waste incineration

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A LOW POWER TIME-TO-DIGITAL CONVERTER FOR ALL-DIGITAL PHASE-LOCKED LOOP

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Journal of Electronics(china) 2011年第3期28卷 402-408页

作者： Yu Guangming Wang Yu Yang Huazhong Department of Electronic Engineering Tsinghua National Laboratory for Information Science and Technology （ TNList） Tsinghua University Beijing 100084 China

Time-to-Digital Converter (TDC) is a key block used as the phase/frequency detector in an All-Digital Phase-Locked Loop (ADPLL). Usually, it occupies a large proportion of ADPLL's total power consumption up to about 30% to 40%. In this paper, the detailed power consumption of different components in the TDC is analyzed. A Power Management Block (PMB) is presented for the TDC to reduce its power consumption. A 24-bits TDC core with the proposed PMB is implemented in HJTC 0.18 μm CMOS technology. Simulation results show that up to 84% power reduction is achieved using our proposed technique.

关键词： Low power Power management All-Digital Phase-Locked Loop (ADPLL) Time-to-Digital Converter (TDC)

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Spin electromagnetic field and dipole:A localized and quantized field

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science Bulletin 2011年第14期 1472-1481页

作者： FEng ZhengHe national laboratory of information science and technology,Department of Electronic Engineering,tsinghua university,beij.ng 100084,china

This paper investigates the structure of a spin electromagnetic (EM) field and its various physical properties.A spin EM field is an intrinsic mode of free space,which satisfies the spin equations derived from Maxwell equations.A spin mode has two basic properties:the spin along its axis and the localization of electromagnetic *** source and EM structure of this electric and magnetic mode are described in detail in this *** distributed charge and current of a spin mode can be integrated to obtain the electric and magnetic moment,and they can be treated as the electromagnetic dipole.A spin mode possesses both wave and particle properties:a wave number,angular frequency and characteristic speed are its wave parameters;an intrinsic radius,energy and angular momentum are its dynamic *** former is analogous to an EM resonant mode;the latter is similar to the behavior of a particle with intrinsic *** are two kinds of electric modes present,one can be expressed through a pair of charges,and the other can be expressed by a magnetic *** both have the same electric moment,but have different divergence properties.

关键词： spin electromagnetic field spin equation distribution source dipole moment intrinsic radius quantized Plank constant

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Ultralight X-type lattice sandwich structure (Ⅱ):Micromechanics modeling and finite element analysis

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science china(Technological sciences) 2009年第9期52卷 2670-2680页

作者： ZHAng QianCheng1,CHEN AiPing 2,CHEN ChangQing2,3 & LU TianJian2 1 State Key laboratory for Mechanical Behavior of Materials,School of Material science and Engineering,Xi’an Jiaotong university,Xi’an 710049,china 2 MOE Key laboratory for Strength and Vibration,School of Aerospace,Xi’an Jiaotong university,Xi’an 710049,china 3 Department of Engineering Mechanics,AML,tsinghua university,beij.ng 100084,china State Key laboratory for Mechanical Behavior of Materials School of Material Science and Engineering Xi’an Jiaotong University Xi’an China MOE Key laboratory for Strength and Vibration School of Aerospace Xi’an Jiaotong University Xi’an China Department of Engineering Mechanics AML Tsinghua University Beijing China

The methods of homogenization and finite elements are employed to predict the effective elastic constants and stress-strain responses of a new type of lattice structure,the X-structure proposed by the authors in a companion paper. It is shown that in most cases the predictions by the equivalent homogenization theory agree well with the experimental and 3-dimensional finite element calculated results. The theoretical and numerical study supports the argument that the X-structure is superior to the pyramid lattice structure in terms of mechanical strength.

关键词： sandwich panel lattice structure equivalent homogenization finite element model

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Magnetism induced by nonmagnetic dopants in zinc-blende SiC: First-principle calculations

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science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 1-10页

作者： LIU ZhaoQing & NI Jun Department of Physics and Key laboratory of Atomic and Molecular Nanoscience (Ministry of Education), tsinghua university, beij.ng 100084, china 1. Department of Physics and Key laboratory of Atomic and Molecular Nanoscience (Ministry of Education) Tsinghua University Beijing 100084 China

Magnetism induced by the nonmagnetic dopants in the zinc-blende SiC (3C-SiC) is investigated by first-principle calculations. The atoms of the first 20 elements in the periodic table except inert gas are used to replace either Si or C atoms as dopants. We find that some nonmagnetic substitutional dopants (mainly the Group IA, Group IIA, Group IIIB, and Group VIIB elements) prefer the spin-polarized ground states with local magnetic moments. In general, the condition for obtaining the local magnetic moments and the magnetic ground state requires that the dopants are p-type and have large electronegativity difference from the neighboring host atoms. The magnetic moments can be tuned over a range between 1 μ B and 3 μ B by doping with the nonmagnetic elements. The nearest-neighbor exchange couplings J 0 between the local magnetic moments are quite large and the codoping method is proposed to increase the dopant concentration. These imply that the nonmagnetic doping in SiC may exhibit collective magnetism. Moreover, the Group IIA Mg and Ca atoms substituting the preferred Si atoms favor the ferromagnetic ground states with the half-metallic electronic properties, which suggests that Mg or Ca substitutional doping on the Si sites in SiC could be a potential route to fabricating the diluted magnetic semiconductors.

关键词： nonmagnetic dopant magnetism SiC diluted magnetic semiconductor first-principle calculation

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Truncation error calculation based on Richardson extrapolation for variable-step collaborative simulation

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science china(information sciences) 2011年第6期54卷 1238-1250页

作者： ZHAng HeMing 1 , LIAng SiLu 2 , SOng ShiJi 1 & WAng HongWei 3 1 Department of Automation, TNList, tsinghua university, beij.ng 100084, china 2 Computer and information Management Center, tsinghua university beij.ng 100084, china 3 Engineering Design Centre, Engineering Department, Cambridge university, Cambridge CB2 1PZ, UK 1. Department of Automation TNList Tsinghua University Beijing 100084 China2. Computer and Information Management Center Tsinghua University Beijing 100084 China3. Engineering Design Centre Engineering Department Cambridge University Cambridge CB2 1PZ UK

Collaborative simulation is an effective approach to performing simulation analysis for complex systems by integrating models developed for different engineering disciplines. Collaborative simulation issues include the modeling of coupled multidisciplinary systems, and the simulation running time integration of these models that are solved parallelly. Estimation of the local truncation error of coupling models is the key to solve multidisciplinary collaborative simulation problem, which is actually used to restrict the simulation step. This paper presents a variable-step method based on Richardson extrapolation for calculating the local truncation error to solve collaborative simulation problem of multidisciplinary coupling models. Formulas for estimating the local truncation error are derived through theoretical analysis by using integration methods and interpolation technologies, respectively. The simulation experiments are illustrated to validate the accuracy and efficiency of proposed collaborative simulation algorithm in comparison with the usual combinative algorithm.

关键词： multidisciplinary systems collaborative simulation variable-step algorithm error estimation

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Effect of streambed sediment on benthic ecology

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International Journal of Sediment Research 2009年第3期24卷 325-338页

作者： Xuehua DUAN1, Zhao-Yin WAng2, Mengzhen XU3, and Kang ZHAng41 Ph.D., Jiangyin Environmental Monitoring Station, Jiangyin 214431, china, Dept. of Hydraulic Engineering, tsinghua university,2 Prof., State Key laboratory of Hydroscience and Engineering, tsinghua university, beij.ng 100084, china, 3 Doctoral candidate, State Key laboratory of Hydroscience and Engineering, tsinghua university, beij.ng 100084, china,4 Doctoral candidate, State Key laboratory of Hydroscience and Engineering, tsinghua university, beij.ng 100084, china [a] Ph.D. Jiangyin Environmental Monitoring Station Jiangyin 214431 china Dept. of Hydraulic Engineering tsinghua university [b] Prof. State Key laboratory of Hydroscience and Engineering tsinghua university beij.ng 100084 china Tel: 86-10-62773448(O) [c] Doctoral candidate State Key laboratory of Hydroscience and Engineering tsinghua university beij.ng 100084 china [d] Doctoral candidate State Key laboratory of Hydroscience and Engineering tsinghua university beij.ng 100084 china

Benthic macroinvertebrates have been commonly used as indicator species for assessment of aquatic ecology. Streambed sediment, or substrate, plays an important role in habitat conditions for macroinvertebrate communities. Field investigations were done to study the benthic diversity and macroinvertebrate compositions in various stream substrata. Sampling sites with different bed sediment, latitude, and climate were selected along the Yangtze River, the Yellow River, the East River, and the Juma River, in china. The results show that benthic community structures found in different substrata clearly differ, while those found in substrata of similar composition and flow conditions but in different macroclimates are similar. The study, thus, demonstrates that the benthic macroinvertebrate community is mainly affected by substrate composition and flow conditions, but is generally unaffected by latitudinal position and macroclimate. Taxa richness of the macroinvertebrate community was found to be the highest on hydrophyte-covered cobbles, high on moss-covered bedrock, and low on clay beds and cobble beds devoid of plant biomass. Sandy beds are compact and unstable, thus, no benthic macroinvertebrates were found colonizing such substrata. Aquatic insects account for most of the macroinvertebrates collected in these rivers. Different insects dominate in different types of substrata: mainly EPT species (Ephemeroptera, Plecoptera, Trichoptera) in cobble, gravel, and moss-covered bedrock; and Chironomidae larvae in clay beds. The relation between the number of species in the samples and the size of the sampling area fits a power function of the species area. One square meter (1m2) is suggested as the minimum sampling area. A substrate suitability index is proposed by integrating the suitability of sediment, periphyton, and benthic organic materials for macroinvertebrates. The biodiversity of macroinvertebrates increases linearly with the substrate suitability index. Benthic ta

关键词： Streambed sediment Macroinvertebrates Benthic ecology Substrate suitability Biodiversity

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Hexafluoro-2-propanol as a potent cosolvent for chemical ligation of membrane proteins

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science china Chemistry 2011年第1期54卷 110-116页

作者： SHEN Fei,TAng Shan & LIU Lei Department of Chemistry,university of science and technology of china,Hefei 230026,china Key laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology,Ministry of Education Department of Chemistry,tsinghua university.beij.ng 100084,china 1. Department of Chemistry University of Science and Technology of China Hefei 230026 China2. Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology Ministry of Education Department of Chemistry Tsinghua University Beijing 100084 China

The study on membrane proteins is an important challenge mainly because of their very poor solubility in various *** traditional recombinant expression strategy and the native chemical ligation method both have difficulty in generating sufficient amounts of desired proteins with high *** studies have shown that multiply fluorinated alcohols exhibit good ability to dissolve difficult peptide sequences,especially hexafluoro-2-propanol (HFIP).In the present study we systematically studied the capability of solvents containing different percentage of HFIP in dissolving transmembrane *** both HPLC and UV analyses we concluded that 60% HFIP/8 M urea constituted a good solvent *** this solvent system we also optimized conditions to perform native chemical ligation (NCL).Under the optimized conditions we successfully achieved NCL’s for both dipeptide formation and the synthesis of a model protein (Trifolitoxin).These results suggested that HFIP was a potential cosolvent that could be used in the ligation of poorly soluble peptides for the generation of membrane proteins.

关键词： membrane protein native chemical ligation alternative solvent hexafluoro-2-propanol

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