骨髓基质细胞表面CD_(40)分子配基化促进IL-6和Flt3配体的释放及其作用

目的 分析人骨髓基质细胞 (BMSC)CD40 分子及其配体 (CD40 L)的表达 ,观察BMSC经CD40 激发型单抗 (5C11)激发后 ,其培养上清中IL 3、IL 6、Flt3配体 (FL)和干细胞因子 (SCF)含量变化及对纯化脐血CD3 4 + 细胞的作用。方法 新鲜分离人骨髓单个核细胞 ,经体外培养获得BMSC。间接免疫荧光标记 ,流式细胞仪分析细胞表面CD40 和CD40 L的表达 ,并与 5C11(2 0 μg/ml)共同孵育 ,分别于 2 4 ,4 8和 72h取上清液 ,ELISA法测定IL 3、IL 6、FL和SCF含量 ;在与 5C11共同培养 2 4h后 ,收取培养上清 ,与纯化的脐血CD3 4 + 细胞共同孵育 ,1周后进行细胞计数、细胞集落培养 ,并用钙磷脂结合蛋白 (An nexinⅤ )标记 ,流式细胞仪分析细胞凋亡。结果 发现BMSC表达CD40 分子 ,经 5C11激发后 ,BMSCIL 6和FL分泌增加 ,而对IL 3及SCF含量无影响 ;BMSC经 5C11激发培养后支持脐血CD3 4 + 细胞的增殖 ,培养 7d后其细胞数和集落数显著多于对照组 ,且细胞凋亡率低 ,二者差异有显著性 (P <0 .0 1)。结论 BMSCCD40 分子配基化可促进IL 6和FL的分泌 ,并支持CD3 4 + 细胞的增殖 ,CD40 /CD40 L可能通过调节细胞因子的释放参与造血调控。

蟾毒配基磺酸化及基于自制串联固相萃取对磺酸化产物富集的研究

关于抗癌活性的蟾蜍二烯内酯的结构修饰化合物已达到100多个。甾体母核3位磺酸化的蟾蜍二烯内酯是从蟾蜍皮中分离得到的一类具有抗癌活性的微量成分,但目前尚无关于蟾蜍二烯内酯磺酸化修饰的报道。该文以沙蟾毒精为例,首次发展了一种高效的3位磺酸化沙蟾毒精的合成方法,对目标产物进行了结构鉴定。基于自制亲水性材料Click TE-Cys,发展了反相/亲水串联固相萃取的反应产物后处理方法,用于磺酸化沙蟾毒精的富集。依此法对总蟾毒配基进行了磺酸化和目标产物的富集及LC-MS定性分析,实现了大量具有潜在抗癌活性的新化合物的制备和富集,为进一步实现高效低毒化合物的筛选提供了物质基础。

基于核磁共振饱和转移差谱技术筛选Protein A仿生多肽配基

核磁共振饱和转移差谱(STD-NMR)技术能够用于检测小分子配基与大分子蛋白之间的亲和性。利用STD⁃NMR技术评价了基于Protein A设计的仿生肽段与人抗体(hIgG)的亲和力以及结合机制,从中筛选出了与抗体亲和性最强的仿生六肽FYEILH,利用静态吸附试验确定了此六肽与抗体的亲和力(Kd)为0.8×10^-6 mol/L,静态结合载量为61.22 mg/mL,与目前文献中报道的许多多肽配基相比,具有明显的优势。在本研究中成功将Protein A最小化,获得了与抗体具有高亲和性的Protein A仿生多肽配基。

[(n-C_4H_9)_3SnO_2C(CH_2)_2CO_2Sn(C_4H_9-n)_3]: A Novel Three-dimensional Framework Structure of Organotin Complex

The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-crystal diffraction. It belongs to orthorhombic with space group Pccn, a = 20.949(3), b = 17.470(3), c = 20.345(3) Angstrom, V = 7446(2) Angstrom(3), Z = 8, D-c = 1.242 g/cm(3), mu = 1.365 mm(-1), F(000) = 2864, R = 0.0544 and wR = 0.1417. The tin atom is of five-coordination in a trigonal bipyramidal structure by bridging two carboxylate groups in different directions and the resulting structure which contains straight twist large ring channels along the axes of a, b and c is a three-dimensional framework polymer containing two different tin atoms.

Enantioselective epoxidation of olefins with hydrogen peroxide catalyzed by bioinspired aminopyridine manganese complexes derived from L-proline

Three chiral aminopyridine ligands derived from L-proline were prepared. Careful evaluation of the corresponding aminopyridine manganese complexes in asymmetric epoxidation of olefins revealed a broad substrate scope in the presence of 0.2 mol% manganese complex and 0.5 equiv. 2,2-dimethylbutyric acid, with aqueous hydrogen peroxide as an oxidant. A variety of olefins including styrenes, chromenes, and cinnamamides were transformed successfully into the target epoxides with moderate to excellent enantioselectivity（yield up to 95%, ee up to 99%）.

Determination of copper complexation in surface microlayer of Daya Bay and Jiaozhou Bay

Copper complexing ligands concentration (C C) and conditional stability constant of the sea surface microlayer (SML) and subsurface layer (SSL) samples, collected from Daya Bay of Guangdong Province and Jiaozhou Bay of Shandong Province, were determined by anodic stripping voltammetry (ASV) technique. C C of Daya Bay in the SML ranged from 6.19×10-7 to 3.52×10-7 mol/L. C C of Jiaozhou Bay in the SML ranged from 5.30×10-7 to 3.03×10-7 mol/L in August 1998 and from 3.46×10-7 to 1.36×10-7 mol/L in May 2000. The C C concentrations were higher in all surface microlayer samples, compared with corresponding subsurface samples. The average enrichment factors of copper complexation in the SML observed above were 1.58, 1.41 and 1.56, respectively. The enrichment of C C concentration in the microlayer demonstrated that organic ligands had certain buffer action on the toxicity of the enriched trace metals in the same layer. Conditional stability constants of the SML in Jiaozhou Bay were lower than those of the SSL; however, it showed just opposite for Daya Bay. BOD (biological oxygen demand) and COD (chemical oxygen demand) indicated the organic matter content, also showed enriched in the SML. C C had an obvious relationship with BOD or COD.

In Vitro Inhibition of β-Hematin by 2, 4-Diamino-6- Mercaptopyrimidine ＆ 2-Mercaptopyrimidine

Malaria is a disease that has drawn worldwide attention due to the alarming rise of mortality rates particularly in third world countries. During the Plasmodium parasite intraerythrocytic life cycle, metabolic processes include the formation of hemozoin or malaria pigment. This pigment functions in the prevention of oxygen radical-mediated damage to the parasite. Drugs targeting hemozoin formation such as chloroquine and amodaquine are effective and are still used, but recently Plasmodium parasites have become resistant to these drugs, especially against chloroquine. In this study we looked at the potential use of two heterocyclic pyrimidine derivatives as anti-malaria drugs; 2,4-Diamino-6-Mercaptopyrimidine （DAMP） and 2-Mercaptopyrimidine （2-MP）. These compounds bear various coordination sites that enable them to react with metal ions to form coordination compounds. We used two methods for testing the inhibition of ferriprotoporphyrin IX （FP） biomineralisation： semi-quantitative microassay used by Deharo, and a quantitative assay used by G. Blaner and M. Akkawi. We report here the finding that （DAMP） has an in vitro inhibitory effect on I%hematin formation at concentrations and magnitude of nearly similar order to that of chloroquine, 2-MP was found to be effective but to a lower degree than DAMP.

Research on Value Assessment-Based Accurate Identification of Government and Corporate Customers of Telecom Operators

Aiming at discovering target customers,this article establishes the value assessment system for government& corporate customers according to the level,stability and accessibility of customer value.With 137 customers as samples,it builds the government & corporate customer value assessment system through analytic hierarchy process(AHP) and identifies target government &corpora te customers by indicator optimization,model fitting and cluster analysis.All these achievements help accurate identification of high-value government and corporate customers and optimization of resource allocation for customer service.

A novel iron-chelating polyimide network as a visible-light-driven catalyst for photoinduced radical polymerization

With the aim of developing a low-cost and efficient visible-light-driven photocatalyst for radical polymerization,iron-chelating polyimide networks(Fe@MPI)was fabricated by firstly synthesizing photoactive melamine-containing polyimide(MPI)networks and then incorporating Fe(III)cations into the polymer networks.Fe@MPI exhibits a wide absorption spectrum ranging from 220 to 1250 nm and 3.5 times higher photocurrent intensity as compared with the pristine MPI.Based on its excellent photo-electric properties,Fe@MPI was employed as a recyclable heterogeneous catalyst,providing sufficient activity for the visible-light driven radical polymerization to synthesize poly(methyl methacrylate)with molecular weight up to 31.×10^4 g mol.Taking advantage of the heterogeneous nature of the catalyst,Fe@MPI could be facilely regenerated from the polymerization solution by filtration without an obvious loss of its activity.This research provides a novel recyclable catalyst for visible-light driven radical polymerization.

Effect of Diluents on the Extraction of Oxalic Acid by Trialkylphosphine Oxide

In liquid-liquid solvent extraction processes, diluents have a strong influence on the extraction mechanism and efficiency. In this study, benzene, cyclohexane, trichloromethane, carbon tetrachloride, methyl isobutyl ketone (MIBK), butyl acetate, and 1-octanol were used as diluents in the extraction of oxalic acid by trialkylphos-phine oxide (TRPO). The effects of extractant concentration, initial concentration of oxalic acid and diluent type on the extraction equilibrium partition coefficient are analyzed. The sequence of the extraction ability by different diluents is MIBK > butyl acetate > cyclohexane=benzene > carbon tetrachloride > 1-octanol > trichloromethane. Extraction mechanism was analyzed and extraction model parameters were evaluated.

Synthesis and Crystal Structure of Mixed Mo-W Cubane-type Cluster Compound [Mo_2W_2S_4 (μ-OAc)_2 (dtp)_3(dtpH)]·CH_2Cl_2

The cubane-type mixed Mo W cluster[Mo2W2S4 (OAc)2(dtp)3 (dtpH)]·CH2Cl2 (dtp= (EtO)2PS2, dtpH = (EtO)2PS (SH) has been prepared by reduction and addition reaction between dinuclear W2S4 (dtp)2 and Mo(CO)6 in HOAc and Ac2O solution in the presence of dtp-ligand. Crystallographic data: Mr=1632. 71,monoclinic, space group P2/n, a=13. 146 (8), b=11. 961 (5),c=17. 157 (9) β =105. 99(8)°, V=2593(8), Z=2, Dc=2. 09 /cm￣3 ,λ(MoKa) =0.71073 ,F (000)=1578, final R=0. 029, Rw = 0. 041 for 3765 unique intensity data [I≥4σ (I)]. The result of X-ray study and elemental analysis indicated that, in the crystal lattice, molybdenum and tungsten are statistically distributed in the metal positions each with 0. 5 fractional occupation.

Synthesis and Crystal Structure of Dicyanamide (5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetraazacyclo- tetradecane) Copper(II) Percholatehydrate

The copper(II) complex [Cu(teta)N(CN)2](ClO4)H2O (teta = 5,7,7,12,14,14- hexamethyl-1,4,8,11-tetraazacyclotetradecane) has been synthesized and the crystal structure was determined by single-crystal X-ray diffraction. Crystal data: C18H38ClCuN7O5, monoclinic, space group P21/n, a = 8.796(3), b = 11.885(4), c = 23.054(9) , b = 97.540(4)o, V = 2389.3(15) 3, Mr = 531.54, Z = 4, Dc = 1.478 g/cm3, F(000) = 1124, ?= 1.070 mm-1, the final R = 0.0566 and wR = 0.1162 for 4749 observed reflections (I > 2s(I)). The center copper ion is coordinated by five nitrogen atoms in a square pyramidal geometry, with four from the macrocyclic ligand teta and the other one from a nitrile nitrogen atom of dicyanamide which is coordinated to the metal atoms as uni-dentate manner via nitrile nitrogen atom.

Heterogeneous Quality of Experience Guarantees Over Wireless Networks

Quality of experience(Qo E), which is very critical for the experience of users in wireless networks, has been extensively studied. However, due to different human perceptions, quantifying the effective capacity of wireless network subject to diverse Qo E is very difficult, which leads to many new challenges regarding Qo E guarantees in wireless networks. In this paper, we formulate the Qo E guarantees model for cellular wireless networks. Based on the model, we convert the effective capacity maximization problem into the equivalent convex optimization problem. Then, we develop the optimal Qo E-driven power allocation scheme, which can maximize the effective capacity. The obtained simulation results verified our proposed power allocation scheme, showing that the effective capacity can be significantly increased compared with that of traditional Qo E guarantees based schemes.

CRYSTAL STRUCTURE OF RhCl(dppm)_2·H_2O

C50H46OP4ClRh, RhCl(dppm)2 · H2O, Mr = 922. 2, monoclinic, P21/2, a=10. 532(3), b=22.574(8), c=18. 641(8) A, β=93. 41(3)°, V = 4424 (3) A3, Z = 4, Dc=1. 386 g. cm-3, λ(MoKα) = 0. 71073A , F(000) = 1904. The structure was determined by direct methods and difference Fourier syntheses and refined by full-matrix least-squares to final R = 0. 037 and Rw = 0. 036 for 3432 (F> 6. 0σ(F) ) observed reflections. The structure of the title compound contains RhCl-(dppm)2 and non-coordinated H2O molecules. The rhodium atom is coordinated by one chlorine atom and four phosphorus atoms of two DPPM ligands forming a tetragonal pyramidal configuration.

The Concept and Theoretical Implications of Carbon Emissions Rights Based on Individual Equity

Climate change has become a hot topic in international environmental negotiations.For post-Kyoto international climate regime negotiations,many countries have proposed a variety of frameworks to share the emission reduction responsibilities and allocate carbon emission rights,and have tried to quantify the emission reduction obligations of all countries based on the perspectives of international equity and individual equity.In this paper,the authors have distinguished the concepts of carbon emissions rights based on these two perspectives respectively,have analyzed the relationship between carbon emissions per capita and economic development,and have calculated and compared the proportion of cumulative emissions per capita of different countries in history and future,and then authors conclude that emission reduction obligations should be allocated based on each country's conditions,including historical emissions,development stage,and future demands.Developed countries should take the initiative to significantly reduce their emissions because they have already accomplished their industrialization process.However,developing countries are still in the process of industrialization,which requires more emission rights to meet their development needs.For China,the concept of carbon emissions based on individual equity can be used as a theoretical tool for the allocating the international carbon emissions rights.

Synthesis and Crystal Structure of an Azide Bridged Binuclear Zinc(II) Complex Including the Reduced Derivative of Nitronyl Nitroxide, [Zn(Him2Py)(N_3)_2]_2

The title compound [Zn(Him2Py)(N3)2]2 (Zn2C26H38N18O2, Mr = 765.48) has been prepared and structurally characterized by X-ray diffraction methods. It crystallizes in monoclinic, space group P21/n with a = 10.989(3), b = 11.519(3), c = 13.812(4) ? b = 101.700(5), V = 1711.9(9) ?, Z = 2, Dc = 1.485 g/cm3, m(MoKa) = 1.456 mm～1, F(000) = 792, the final R = 0.0401 and wR = 0.0861 for 2054 observed reflections with I>2s(I). The imino nitroxide 2-(3- methyl-2-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl (im2Py) was reduced to obtain 2-(3-methyl -2-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-ydroxy (Him2Py) coordinating to the zinc (II) ion, around which the coordination geometry is a square-based pyramid with a terminal nitrogen atom located at the apical position. The four basal sites are occupied by two m1,1 nitrogen atoms from two different bridging azide ions and two nitrogen atoms from Him2Py. The units of [Zn(Him2Py)(N3)2]2 were connected as two dimension planes by intermolecular hydrogen bonds.

Subcarrier and power allocation in OFDM-based cognitive radio networks

We formulate the subcarrier and power allocation problem in cognitive radio networks employing orthogonal frequency division multiplexing （OFDM） as a non-linear optimization problem with the objective of maximizing sum capacity under constraints of available subcarriers, interference temperature, power budget, etc. A close-to-optimal solution with much reduced complexity is proposed to separate the problem into two steps, which also considers fairness among secondary users. A fair al- gorithm for subcarrier allocation （FA_SA） is firstly presented. Secondly, a fast iterative water-filling algorithm for power allocation （FIWFA_PA） is also proposed to maximize the sum capacity. Exten- sive simulation results show that sum capacity performance of our low-complexity solution is very close to the optimal one, while significantly improving fairness and reducing computation complexity compared with the existing solutions.

New tricks for an old dog: Visible light-driven hydrogen production from water catalyzed by fac-and mer-geometrical isomers of tris(thiosemicarbazide) cobalt(Ⅲ)

Increasing interest has been paid to the development of earth‐abundant metal complexes as promising surrogates of platinum for the electrocatalytically and photocatalytically driven hydrogen evolution reaction.In this work,we report on molecular H2‐evolving catalysts based on two octahedral complexes of cobalt thiosemicarbazide,fac‐[Co(Htsc)3]Cl3·3H2O(C1,Htsc=thiosemicarbazide)and mer‐[Co(Htsc)3]Cl3·4H2O(C2),which have facial(fac)and meridional(mer)geometry,respectively.Electrochemical studies confirmed that both C1and C2are active electrocatalysts in MeOH solution using acetic acid as the proton source,with the same overpotential of^640mV and TOF of^210s–1.The complex C1also exhibits electrocatalytic activity for hydrogen evolution reaction in aqueous media free of organic solvent with a moderate overpotential(560mV).Visible light‐driven hydrogen evolution experiments were carried out in combination with fluorescein as photosensitizer and triethylamine as sacrificial reductant in homogeneous environments.Our studies showed that both C1and C2can be used as efficient proton‐reduction catalysts in purely aqueous solution and have the same photocatalytic activities.A TOF of125h–1with a TON of900for photocatalytic H2generation using C1and C2in water were achieved for the noble‐metal‐free homogeneous system.It should be noted that this is the first reported study investigating the effect on the catalytic hydrogen production performance of using fac‐and mer‐isomers of molecular catalysts.

Functions of the MMR system and special roles of mutL in bacterial evolution

DNA mismatch repair guards the integrity of the genome of almost all organisms by correcting DNA biosynthetic errors and by ensuring the fidelity of homologous genetic recombination. MutL is one of the important proteins involved in mismatch repair system. It has been suggested to function as a master coordinator or molecular matchmaker because it interacts physically with MutS, the endonuclease MutH, and DNA helicase UvrD. It also binds to DNA and has an ATPase activity. MutL defective bacteria strains have elevated mutation rates and it has been reported recently that MutL defect may have an important impact on bacterial evolution.

Switching Delay Aware Computing Resource Allocation in Virtualized Base Station

In centralized cellular network architecture,the concept of virtualized Base Station(VBS) becomes attracting since it enables all base stations(BSs) to share computing resources in a dynamic manner. This can significantly improve the utilization efficiency of computing resources. In this paper,we study the computing resource allocation strategy for one VBS by considering the non-negligible effect of delay introduced by switches. Specifically,we formulate the VBS's sum computing rate maximization as a set optimization problem. To address this problem,we firstly propose a computing resource schedule algorithm,namely,weight before one-step-greedy(WBOSG),which has linear computation complexity and considerable performance. Then,OSG retreat(OSG-R) algorithm is developed to further improve the system performance at the expense of computational complexity. Simulation results under practical setting are provided to validate the proposed two algorithms.