检索结果-南通市图书馆

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第2期12卷 116-125页

作者： Qiu-lei LANG Xiao-chuan ZHOU Xiao-lin ZHANG Rafal DRABEK Zhi-xiang ZUO Yong-liang REN Tong-bin LI Ji-shuang CHEN Xiao-lian GAO College of Life sciences Zhejiang University Hangzhou 310058 China Institute of Bioengineering Zhejiang Sci- Tech University Hangzhou 310018 China lc sciences 2575 W. Bellfort Suite 270 Houston ZY 77054 USA Department of Biology and Biochemistry University of Houston Houston TX 77004 USA

A large number of plant microRNAs (miRNAs) are now documented in the miRBase, among which only 30 are for Solanum lycopersicum (tomato). Clearly, there is a far-reaching need to identify and profile the expression of miRNAs in this important crop under various physiological and pathological conditions. In this study, we used an in situ synthesized custom microarray of plant miRNAs to examine the expression and temporal presence of miRNAs in the leaves of tomato plants infected with Cucumber mosaic virus (CMV). Following computational sequence homology search and hairpin structure prediction, we identified three novel tomato miRNA precursor genes. Our results also show that, in accordance with the phenotype of the developing leaves, the tomato miRNAs are differentially expressed at different stages of plant development and that CMV infection can induce or suppress the expression of miRNAs as well as up-regulate some star miRNAs (miRNA*s) which are normally present at much lower levels. The results indicate that developmental anomalies elicited by virus infection may be caused by more complex biological processes.

关键词： Solanum lycopersicum Plant miRNA Cucumber mosaic virus miRNA array miRNA response

MicroRNAs: Mechanisms, Functions and Progress

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2012年第5期10卷 237-238页

作者： Tongbin Li William C.S.Cho *** Research Group LC SciencesHoustonTX 77054USA Department of Clinical Oncology Queen Elizabeth HospitalHong Kong SARChina

In 1993 when Ambros and co-workers [1] discovered that a mysterious Caenorhabditis elegans gene, lin-4, does not encode a protein, but acts in the form of a small RNA and represses the expression of its target gene, lin-14, through base-pairing with its 3＇ untranslated region （3tUTR）, nobody would imagine that 20 years later, this category of small RNAs - now widely known as microR- NAs （or miRNAs）, has ～2000 known members in the human genome （and counting）, and that miRNA-mediated gene regulation is deeply involved in virtually all important biological processes in animals and plants.

关键词： Caenorhabditis elegans biological processes gene regulation human genome target gene small RNA form of

Simultaneous determination of three classes of antibiotics in the suspended solids of swine wastewater by ultrasonic extraction,solid-phase extraction and liquid chromatography-mass spectrometry

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2011年第10期23卷 1729-1737页

作者： Xun Pan Zhimin Qiang Weiwei Ben Meixue Chen Research Center for Eco-Environmental sciences Chinese Academy of Sciences Beijing 100085 China

This work describes a systematic approach to the development of a method for simultaneous determination of three classes of veterinary antibiotics in the suspended solids （SS） of swine wastewater, including five sulfonamides, three tetracyclines and one macrolide （tiamulin）. The entire procedures for sample pretreatment, ultrasonic extraction （USE）, solid-phase extraction （SPE）, and liquid chromatography-mass spectrometry （lc-MS） quantification were examined and optimized. The recovery efficiencies were found to be 76%-104% for sulfonamides, 81%-112% for tetracyclines, and 51%--64% for tiamulin at three spiking levels. The intra-day and inter-day precisions, as expressed by the relative standard deviation （RSD）, were below 17%. The method detection limits （MDLs） were between 0.14 and 7.14 μg/kg, depending on a specific antibiotic studied. The developed method was applied to field samples collected from three concentrated swine feeding plants located in Beijing, Shanghai and Shandong province of China. All the investigated antibiotics were detected in both SS and liquid phase of swine wastewater, with partition coefficients （logKd） ranging from 0.49 to 2.30. This study demonstrates that the SS can not be ignored when determining the concentrations of antibiotics in swine wastewater.

关键词： antibiotics swine wastewater suspended solids ultrasonic extraction solid-phase extraction mass spectrometry

Elimination, Kinetics and Thermodynamics of Fe(II) Ions by Adsorption in Static and Dynamic Conditions on Activated Carbons in Aqueous Media

在线全文

学校读者我要写书评

暂无评论

Journal of Geoscience and Environment Protection 2024年第10期12卷 181-203页

作者： Spenseur Bouassa Mougnala Charly Mve Mfoumou Berthy Lionel Mbouiti Pradel Tonda-Mikiela Francis Ngoye Ferdinand Evoung Evoung Jean Aubin Ondo Guy Raymond Feuya Tchouya Laboratoire de Chimie des Milieux et des Matriaux Inorganiques (lc2MI) Dpartement de Chimie Universit des Sciences et Techniques de Masuku (USTM) Franceville Gabon Ecole Doctorale des sciences Fondamentales et Appliques (ED-SFA) LC2MI USTM Franceville Gabon Dpartement de Chimie Facult des Sciences (FS) USTM Franceville Gabon Laboratoire Pluridisciplinaire des sciences (LAPLUS) Ecole Normale Suprieure (ENS) Libreville Gabon

This work investigated the removal, kinetics and thermodynamics of iron(II) ions (Fe(II)) by adsorption in static and dynamic conditions in aqueous media on activated carbons (AC-i30min, AC-i1h, and AC-i24h), prepared from palm nut shells collected in the city of Franceville to Gabon, using potassium hydroxide (KOH) as the activating agent. Results on the elimination of Fe(II) in static and dynamic adsorption on prepared activated carbons (ACs) showed that the AC-i24h adsorbent has the best Fe(II) adsorption capacities at saturation (Qsat). The Qsat obtained on AC-i24h in static and dynamic conditions (17.87 and 10.38 mg/g, respectively) were higher than those of AC-i30min (13.89 and 5.54 mg/g respectively) and AC-i1h (14.92 and 8.64 mg/g respectively). Moreover, the static adsorption was more effective in the removal of Fe(II) ions in aqueous media in our experimental conditions. The percentage removal (%E) of Fe(II) obtained on prepared activated carbons in static conditions was better than those obtained in dynamic conditions, especially on AC-i24h, where the %E was 89.27% in static and 61.56% in dynamic. In kinetics, results showed that the pseudo-second-order kinetic model best described the adsorption mechanisms of Fe(II) on prepared activated carbons in static adsorption, with mainly of chemisorption on the solid surfaces. However, in dynamic conditions, the pseudo-first-order kinetic model was more suitable. In addition to the weak interactions between Fe(II) and the activated carbon surfaces, strong interactions (chemisorption) were also observed. Also, thermodynamic data obtained on AC-i24h in static adsorption indicated that the adsorption of Fe(II) was spontaneous and increased with temperature (ΔG˚ H˚ = 503.54 KJ/mol).

关键词： Palm Nut Shells Activated Carbon Removal Fe(II) Static and Dynamic Adsorption Kinetics Thermodynamics

Preparation and Characterization of Activated Carbons from Palm Nut Shells: Effects of Calcination Temperature on Porosity and Chemical Properties

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Inorganic Chemistry 2024年第2期14卷 19-32页

作者： Charly Mve Mfoumou Berthy Lionel Mbouiti Spenseur Bouassa Mougnala Pradel Tonda-Mikiela Guy Raymond Feuya Tchouya Laboratoire de Chimie des Milieux et des Matriaux Inorganiques (lc2MI) URCHI Universit des Sciences et Techniques de Masuku (USTM) Franceville Gabon Dpartement de Chimie Facult des Sciences Universit des Sciences et Techniques de Masuku (USTM) Franceville Gabon Ecole Doctorale des sciences Fondamentales et appliques (ED-SFA) Laboratoire de Chimie des Milieux et des Matriaux Inorganiques (LC2MI) URCHI USTM Franceville Gabon

Activated carbons (ACs) calcined at 400˚C, 500˚C, and 600˚C (AC-400, AC-500, and AC-600) were prepared using palm nut shells from Gabon as raw material and zinc chloride (ZnCl2) as a chemical activating agent. Prepared ACs were characterized by physisorption of nitrogen (N2), determination of diode and methylene blue numbers for studies of porosity and by quantification and determination of surface functional groups and pH at point of zero charge (pHpzc) respectively, for studies of chemical properties of prepared ACs. Then, effects of calcination temperature (Tcal) on porosity and chemical properties of prepared ACs were studied. The results obtained showed that when the calcination temperature increases from 500˚C to 600˚C, the porosity and chemical properties of prepared ACs are modified. Indeed, the methylene blue and iodine numbers determined for activated carbons AC-400 (460 and 7.94 mg·g−1, respectively) and AC-500 (680 and 8.90 mg·g−1, respectively) are higher than those obtained for AC-600 (360 and 5.75 mg·g−1, respectively). Compared to the AC-500 adsorbent, specific surface areas (SBET) and microporous volume losses for AC-600 were estimated to 44.7% and 45.8%, respectively. Moreover, in our experimental conditions, the effect of Tcal on the quantities of acidic and basic functional groups on the surface of the ACs appears negligible. In addition, results of the pHpzc of prepared ACs showed that as Tcal increases, the pH of the adsorbents increases and tends towards neutrality. Indeed, a stronger acidity was determined on AC-400 (pHpzc = 5.60) compared to those on AC-500 and AC-600 (pHpzc = 6.85 and 6.70, respectively). Also according to the results of porosity and chemical characterizations, adsorption being a surface phenomenon, 500˚C appears to be the optimal calcination temperature for the preparation of activated carbons from palm nut shells in our experimental conditions.

关键词： Palm Nut Shells Activated Carbon Calcination Temperature Porosity and Chemical Properties

Monotone Span Program vs. Linear Code

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2016年第6期25卷 991-998页

作者： TANG Chunming CHEN Yuenai GAO Xuhong School of Mathematics and Information sciences Guangzhou University Key Laboratory of Mathematics and Interdisciplinary sciences of Guangdong Higher Education Institutes Guangzhou University Department of Mathematical sciences Clemson University

Monotone span program(MSP) and Linear code(lc) are efficient tools to construct Linear secret sharing scheme(LSSS) for a given access structure. Since the size of an MSP or the length of an lc corresponds to the communicational complexity of an LSSS, one main motivation to study MSPs or lcs is the lower bound for their sizes or lengths. Therefore, it is one of the most important open problems how to efficiently construct an MSP or lc for a given access structure Γ with the smallest sizes or shortest length. Our contributions are: We extend TANG et al.’s result, showing that, for any given access structureΓ, there exists an MSP or an lc to realize Γ if and only if a system of quadratic equations has solutions; We utilize the relationship between lcs and MSPs to obtain the greatest lower bound on the row size and the column size of MSPs realizing a given Γ, as well as an upper bound on the column size of MSPs; We give an algorithm to construct an MSP with the smallest sizes.

关键词： Cryptography Secret sharing scheme Monotone span program Linear code Size

Quantum state measurement in double quantum dots with a radio-frequency quantum point contact

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第2期23卷 87-92页

作者：严蕾王海霞殷雯王芳卫 Institute of Physics Chinese Academy of Sciences

We study the dynamics of two electron spins in coupled quantum dots （CQDs） monitored by a quantum point contact （QPC） detector. Their quantum state can be measured by embedding the QPC in an lc circuit. We derive the Bloch-type rate equations of the reduced density matrix for CQDs. Special attention is paid to the numerical results for the weak measurement condintion under a strong Coulomb interaction. It is shown that the evolution of QPC current always follows that of electron occupation in the right dot. In addition, we find that the output voltage of the circuit can reflect the evolution of QPC current when the circuit and QPC are approximately equal in frequency. In particular, the wave shape of the output voltage can be improved by adjusting the circuit resonance frequency and bandwidth.

关键词： measurement quantum state output voltage circuit parameter

Identification of unknown disinfection byproducts in drinking water produced from Taihu Lake source water

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2022年第3期34卷 1-11页

作者： Jiabao Li Haifeng Zhang Juan Wang Zhiyong Yu Hongyan Li Min Yang Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesUniversity of Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of sciences Beijing 100049China

Although disinfection byproducts(DBPs) in drinking water have been suggested as a cancer causing factor, the causative compounds have not yet been clarified. In this study, we used liquid chromatography quadrupole-time-of-flight spectrometry(lc-QTOF MS) to identify the unknown disinfection byproducts(DBPs) in drinking water produced from Taihu Lake source water, which is known as a convergence point for the anthropogenic pollutants discharged from intensive industrial activities in the surrounding regions. In total, 91 formulas of DBPs were discovered through lc-QTOF MS nontarget screen, 81 of which have not yet been reported. Among the 91 molecules, 56 only contain bromine, 15 only contain chlorine and 20 DBPs have both bromine and chlorine atoms. Finally, five DBPs including 2,4,6-tribromophenol, 2,6-dibromo-4-chlorophenol, 2,6-dichloro-4-bromophenol, 4-bromo-2,6-di-tert-butylphenol and 3,6-dibromocarbazole were confirmed using standards. The former three compounds mainly formed in the predisinfection step(maximum concentration, 0.2-2.6 μg/L), while the latter two formed in the disinfection step(maximum concentration, 18.2-33.6 ng/L). In addition, 19 possible precursors of the discovered DBPs were detected, with the aromatic compounds being a major group. 2,6-di-tert-butylphenol as the precursor of 4-bromo-2,6-di-tert-butylphenol was confirmed with standard, with a concentration of 20.3 μg/L in raw water. The results of this study show that brominated DBPs which are possibly formed from industrial pollutants are relevant DBP species in drinking water produced form Taihu source water, suggesting protection of Taihu Lake source water is important to control the DBP risks.

关键词： Source water Disinfection byproducts Brominated disinfection byproducts Nontarget analysis Precursors Source water pollution

Pyrolytic characteristics and kinetics of the marine green tide macroalgae, Enteromorpha prolifera

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Oceanology and Limnology 2011年第5期29卷 996-1001页

作者：赵辉闫华晓刘明张从旺秦松 Institute of Oceanology Chinese Academy of Sciences Graduate University of Chinese Academy of sciences Shandong University of Science and Technology Institute of Process Engineering Chinese Academy of Sciences

The marine macroalgae Enteromorpha prolifera was one of the main algal genera that occurred in the widespread green tides in Qingdao, China, during the summers of 2007, 2008 and 2010. It is thus a plentiful source of biomass and could be used as a biofuel. In this study, the pyrolytic characteristics and kinetics of E. prolifera were investigated using thermogravimetric analysis (TGA) method. Cornstalk and sawdust were used as comparisons. Pyrolytic characteristics were studied using TG-DTG (thermogravimetry-derivative thermogravimetry) curves. Three stages in the pyrolytic process were determined: dehydration, dramatic weight loss and slow weight loss. E. prolifera was pyrolyzed at a lower initial temperature than the two terrestrial biomass forms. The apparent activation energy values for the three types of biomass were calculated and the mechanism functions were determined using 16 different mechanism functions, frequently used in thermal kinetics analysis. Activation energy values varied with mechanism function and the range of activation energy values for E. prolifera, cornstalk, and sawdust were 25-50 kJ/mol, 60-90 kJ/mol and 120-155 kJ/mol, respectively. This indicates that E. prolifera has low thermal stability for pyrolysis and good combustion characteristics.

关键词： macroalgae green tide Enteromorpha prolifera pyrolysis kinetics

Development and validation of an lc-MS/MS method for tyrphostin A9

在线全文

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2019年第3期9卷 163-169页

作者： Lyndsey F.Meyer Dhaval K.Shah Department of Pharmaceutical sciences School of Pharmacy and Pharmaceutical SciencesThe State University of New York at Buffalo

Here we have presented a sensitive and selective lc-MS/MS method for the quantification of tyrphostin A9, which is a selective inhibitor for platelet derived growth factor receptor tyrosine kinase and has been investigated in vitro as a potent oxidative phosphorylation uncoupler. The murine analytical method was developed for three biological matrices: cell culture media, 3T3-L1 cell lysate, and murine plasma. For each matrix the limit of detection and the limit of quantification were found to be 0.5 ng/mL and 1.0 ng/ mL, respectively. The range of standard curve for each matrix was 1.0-100 ng/mL, linearity was >0.99, and the precision and accuracy were within 20%. 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoic acid was found to be the most suitable internal standard. The validated lc-MS/MS method was used to investigate stability and in vitro pharmacokinetics of tyrphostin A9. It was found that tyrphostin A9 is susceptible to hydrolysis, and the degradation product was identified as 3,5-di-tert-butyl-4- hydroxybenzaldehyde. Tyrphostin A9 was not stable in biological matrices, and the rate of its degradation in murine plasma was faster than that in cell culture media. In vitro pharmacokinetic studies revealed that tyrphostin A9 concentrations in the cell culture media declined in a bi-exponential manner and the concentrations inside the adipocytes remained constant, suggesting tyrphostin A9 has an intracellular binding site and is retained within the cell. The lc-MS/MS method presented here paves the way for further quantitative investigations involving tyrphostin A9.

关键词： Tyrphostin 9/ A9/AG-9/Malonoben/SF6847 lc-MS/MS Stability Pharmacokinetics Tyrosine kinase inhibitor