Synthesis, crystal structure and magnetic properties of a series of polymeric lanthanoid-copper complexes [Ln(2)Cu(3){O(CH2-CO2)(2)}(6)].nH(2)O (Ln=La, Nd, n=9; Ln=Er, n=6)

The reaction of diglycolic acid, O(CH2CO2H)(2), with Cu(NO3)(2) . H2O and lanthanoid nitrate hydrate produces a series of novel Ln-Cu mixed metal complexes, [Ln(2)CU(3){O(CH2CO2)(2)}(6)]. nH(2)O (Ln = La, Nd, n = 9; Ln = Er, n = 6), which have been characterized by elemental analysis, i.r. spectroscopy, magnetic measurements and X-ray crystallography. The Ln(3+) and Cu2+ ions are connected by the carboxylate groups of the ligands, resulting in the formation of a complicated network.

Viologen-thiol self-assembled monolayers for immobilized horseradish peroxidase at gold electrode surface

A stable, well-behaved self-assembled monolayer (SAM) of viologen-functionalized thiol was used to immobilize and electrically connect horseradish peroxidase (HRP) at gold electrode. Viologen groups in SAMs facilitated the electron transfer from the electrode to the protein active site so that HRP exhibited a quasi-reversible redox behavior. HRP adsorbed in the SAMs is very stable, and close to a monolayer with the surface coverage of 6.5 x 10(-11) mol/cm(2). The normal potential of HRP is -580 mV vs Ag/AgCl corresponding to ferri/ferro active center and the standard electron transfer rate constant is 3.41 s(-1) in 0.1 M phosphate buffer solution (pH 7.1). This approach shows a great promise for designing enzyme electrodes with other redox proteins and practical use in tailoring a variety of amperometric biosensor devices. Copyright (C) 1997 Elsevier Science Ltd.

The crystal structure and supramolecular chain of [La(NO3)(3)(OH2)(2)(phen)]center dot 15-crown-5

[La(NO3)(3)(OH2)(2)(phen)]. 15-crown-5 is hexagonal, P6(5), with a = 10.955(2), c = 43.769(9) Angstrom, and D-calc = 1.668 g cm(-3) for Z = 6. In the complex, two nitrogen atoms (from phen) and eight oxygen atoms (six from three bidentate nitrate anions and two from water molecules) are coordinated to the central La(III) ion, forming a coordination polyhedron which is approximately a bicapped square antiprism. The coordinated water molecules donate hydrogen bonds to the oxygen atoms of the crown ether, forming polymeric hydrogen bonded chains which wrap helically along the unit cell direction c.

CRYSTAL-STRUCTURES OF LN(NO3)(3) (LN=EU,LU) COMPLEXES WITH A CROWN-ETHER (16-CROWN-5)

The crystal structures of Ln(NO3)(3)(Ln = Eu,Lu) complexes with 16-crown-5 are reported. In [Eu(NO3)(2)(CH3CN)(16-crown-5)][Eu(NO3)(4)(H2O)2].1/2(16-crown-5) one Eu-III ion is coordinated to two bidentate nitrate ions, one acetonitrile molecule and five o

CRYSTAL-STRUCTURE OF [YB (NO3)3 (PHEN) (H2O)]CENTER-DOT(12-CROWN-4)

The title complex was prepared by reacting Yb(NO3)3 (12-crown-4) with 1, 10-phenanthiroline (hereafter phen) in acetone. It crystallized in the triclinic space group P1BAR with a = 10.095(5), b = 17.415(4), c = 8.710(2) angstrom; alpha = 92.45(2), beta = 115.83(3), gamma = 74.08(3)degrees and D(c), = 1.85 g cm-3; Z = 2. The metal ion in this complex is nine-coordinated to three bidentate nitrate ions, two nitrogen atoms of a phen and a water molecule. The crown ligand is hydrogen bonded to the coordination water molecule. The symmetry change of the crown ether is also discussed.

SURFACE-MODIFIED HYDROPHILIC MEMBRANES IN MEMBRANE DISTILLATION

The porosity and the hydrophobicity of membranes are two essential requirements for membrane distillation (MD) of aqueous solutions. So far, the hydrophobic porous membranes used in MD studies have been prepared from hydrophobic materials. In this work, hydrophilic cellulose acetate and cellulose nitrate membranes were modified into hydrophobic membranes by radiation grafting polymerization and plasma polymerization, and used in MD studies successfully. The results indicated that modified membranes with good performance in MD can be obtained if the modifying conditions are controlled appropriately. Especially plasma polymerization, in which many particular kinds of monomer could be polymerized onto the surface of porous materials, has become an efficient method to prepare hydrophobic porous membrane with high performance from hydrophilic membranes. It will stimulate the development and practical application of MD.

WATER-SOLUBLE AND AMPHIPHILIC POLYMERS .11. GRAFT-POLYMERIZATION OF ACRYLIC-ACID ON POLY(VINYL ALCOHOL)

The graft polymerization of acrylic acid(AA) on poly(vinyl alcohol) (PVAL) has been investigated by using either potassium persulfate (KPS) or ceric ammonium nitrate(CAN) as an initiator. In the case of KPS initiation, the formation of the graft polymer always lags behind the homopolymer formation. The graft polymer is separated by acetone, and the increase of reaction temperature favors the homopolymer formation at the early stage. In the case of CAN initiation, graft polymers with a high PAA content can hardly be obtained when the polymerization is performed under nitrogen and at < 0.06 mol/L HNO3 concentration. It has been found that incorporation of a small amount of oxygen in a protective nitrogen gas accelerates markedly the graft polymerization, and that the resulting graft polymers can not be separated by acetone precipitation technique in most cases. The Dalian nitrogen(containing 0.7% oxygen) is a good protective gas for CAN-initiated PVAL-AA graft polymerization.

PLASMA POLYMERIZATION OF OCTAFLUOROCYCLOBUTANE AND HYDROPHOBIC MICROPOROUS COMPOSITE MEMBRANES FOR MEMBRANE DISTILLATION

In this paper, hydrophilic microporous cellulose nitrate membranes have been surface-modified by plasma polymerization of octafluorocyclobutane (OFCB). The microporous composite membranes with a hydrophilic layer sandwiched between two hydrophobic layers have been obtained. The obtained composite membranes have been used in a membrane distillation (MD) process and have exhibited good performance. The effects of polymerization conditions, such as glow-discharge power and deposition time, on the structures and MD performances of the obtained composite membranes have been investigated by SEM, X-ray microscopical analysis, and XPS. The polymerization conditions should be as mild as possible in order to prepare the hydrophobic composite membrane with good MD performance. The typical MD behaviors of the obtained hydrophobic composite membranes are in agreement with that of hydrophobic membranes directly prepared from hydrophobic polymeric materials, like PVDF, PTFE, or PP.

POLYANILINE CHEMICALLY MODIFIED ELECTRODE FOR DETECTION OF ANIONS IN FLOW-INJECTION ANALYSIS AND ION CHROMATOGRAPHY

An electrochemical detector based on a polyaniline conducting polymer chemically modified electrode (PAn CME) was developed for use in flow-injection analysis and ion chromatography. Iodide, bromide, thiocyanate and thiosulphate are detected by using ion chromatography with a PAn CME electrochemical detector. The detection limits are 1, 5, 10 and 10 mgl-1, respectively. The CME response for electroinactive anions varies selectively with the mobile phase composition in flow-injection analysis. By this approach, perchlorate, sulphate, nitrate, iodide, acetate and oxalate can be detected conveniently and reproducibly over a linear concentration range of at least 3 orders of magnitude. The electrode is stable for over 2 weeks with no evidence of chemical or mechanical deterioration.

Microprojectile bombardment of Laminaria japonica gametophytes and rapid propagation of transgenic lines within a bubble-column bioreactor

A human acidic fibroblast growth factor gene, hafgf, was successfully transferred into Laminaria japonica (kelp) gametophytes via microprojectile bombardment using the biolistic PDS-1000/He gene gun. Following phosphinothricin screening, PCR detection and Southern blot analysis, transgenic L. japonica gametophytes were cultivated in an illuminated bubble-column bioreactor to optimize growth conditions. A maximal final dry cell density of 1,695 mg l(-1) was obtained in a batch culture having an initial dry cell density of 129.75 mg l(-1). This was achieved using an aeration rate of 1.08 l air min(-1) l(-1) culture in a medium containing 1.5 mM inorganic nitrate and 0.15 mM phosphate. In addition, the relationship between different nitrogen sources and growth of transgenic gametophytes indicated that both urea and sodium nitrate were effective nitrogen sources for cell growth, while ammonium ions inhibited growth of these gametophytes.

Suspension culture of gametophytes of transgenic kelp in a photobioreactor

Transgenic Laminaria japonica gametophytes producing a recombinant tissue-type plasminogen activator (rtPA) protein, which is an effective third-generation thrombolytic agent for acute myocardial infarction (AMI), were cultured in an illuminated bubble column bioreactor. A maximum final dry cell weight of 1120 mg l(-1) was obtained in batch culture with an initial dry cell weight of 126 mg l(-1) and with aeration rate of 1.2 l air min(-1) l(-1) culture, nitrate at 1.5 mM and phosphate at 0.17 mM. The yield of rtPA was 56 mu g g(-1) dry cell wt. This is the first report regarding cultivation of a transgenic macroalga in a bioreactor.

Mass culture of Undaria gametophyte clones and their use in sporeling culture

Undaria pinnatifida (Harv.) Sur. is one of the three main seaweed species under commercial cultivation in China. In the mid-1990s the annual production was about 20000 tons dry. The supply of healthy sporelings is key to the success of commercial cultivation of Undaria. Previous studies demonstrated that instead of the zoospore collection method, sporelings can be cultured through the use of gametophyte clones. This paper reports the experimental results on mass culture of clones and sporeling raising in commercial scale. Light had an obvious effect on growth of gametophyte clones. Under an irradiance of 80 mumol m(-2) s(-1) and favorable temperature of 22-25degreesC, mean daily growth rate may reach as high as 37%. Several celled gametophyte fragments were sprayed onto the palm rope frame. Gametogenesis occurred after 4-6 days. Juvenile sporeling growth experiments showed that nitrate and phosphate concentrations of 2.9 10(-4) mol 1(-1) and 1.7 10(-5) mol 1(-1) were sufficient to enable the sporelings to maintain a high daily growth rate. Sporelings can reach a length of 1 cm in a month. Since 1997, extension of the clone technique has been carried out in Shandong Province. Large-scale production of sporelings for commercial cultivation of 14 and 31 hectares in 1997 and 1998 had been conducted successfully.

Optimization of conditions for cell cultivation of Porphyra haitanensis conchocelis in a bubble-column bioreactor

Process conditions for cell cultures derived from conchocelis of female red macroalga Porphyra haitanensis were optimized in an illuminated 0.3-l bubble-column photobioreactor, using CO2 in air as the sole carbon source during a 20-day cultivation period. It reached the highest growth rate when the initial cell density was 700 mg l(-1)(dry weight), the optional aeration rate was 1.2 v/v/min, inorganic nitrate concentration was 15 mM and inorganic phosphate concentration was 0.6 mM. This is the first reported bioreactor cultivation study of cell cultures derived from conchocelis of Porphyra haitanensis.

长江口上升流区营养盐动力学

近年来，东中国海赤潮灾情严重，且74.7%的赤潮集中在 30°30′～32°00′N、122°15′～123°10′E的“赤潮高发区”。在研究该区赤潮成因时，长江口沿岸上升流的影响越来越受到人们的关注，并被一些专家观测和研究。但目前为止，针对该区营养盐动力学特征及其对叶绿素a影响的研究较少，且不系统。 本文根据2004年四个季度月的调查资料，系统地探讨了长江口上升流区营养盐动力学特征；估算了上升流的营养盐通量，并和陆源输入通量进行了比较。初步探讨了上升流对该区营养盐结构和浮游植物生长的影响。为深入研究长江口富营养化和赤潮形成机制提供了参考。 结果表明春季在122°20′～123°00′E，31°00′～32°00′N以北海域存在低温、高盐、低溶解氧的沿岸上升流。它不但可把底层高含量磷酸盐输送到10m层以上海区，而且还为上层海区输入了相对低含量硝酸盐和硅酸盐，从而改善了上层营养盐结构，使得营养盐比值接近Redfield Ratios，同时还改善了上层的透明度；从而有利于浮游植物的繁殖。夏季上升流受到强大的长江冲淡水压制，表现不如春季明显，主体水团出现在122°20′～123°00′E，31°15′～31°50′N海区10m层以下。 在秋、冬季，上升流现象被更强的对流现象所掩盖，表现为台湾暖流表层水的入侵。表、底层水域不仅温、盐度分布十分接近，而且营养盐结构差异也较小。冬季台湾暖流水中的磷酸盐含量远比秋季高，与春、夏季上升流水团中磷酸盐含量接近。硝酸盐和硅酸盐含量比秋季稍高，比春、夏季上升流水团中的含量稍低。 叶绿素a季节性分布表明，在春、夏季的10m层以下水域，叶绿素a受到透明度限制，含量相差不大；而在表层和10m层之间，春季叶绿素a的含量远高于夏季，说明春季的营养盐结构和自然条件更有利于浮游植物的繁荣生长。在秋季台湾暖流水影响的区域，表层叶绿素a含量较夏季稍低。而冬季该区叶绿素a含量则是最低的。 对长江口上升流水团春季营养盐通量的计算结果表明，上升流水团中磷酸盐输送通量远远高于长江径流输入，是其径流通量的两倍以上，可能会成为影响该海区磷酸盐分布以及浮游植物生长的一个值得关注的因素。 关键词：上升流，营养盐动力学，营养盐结构，叶绿素a，长江冲淡水

Seasonal and interannual variability of primary and export production in the South China Sea: a three-dimensional physical-biogeochemical model study

To investigate the seasonal and interannual variations in biological productivity in the South China Sea (SCS), a Pacific basin-wide physical - biogeochemical model has been developed and used to estimate the biological productivity and export flux in the SCS. The Pacific circulation model, based on the Regional Ocean Model Systems (ROMS), is forced with daily air-sea fluxes derived from the NCEP (National Centers for Environmental Prediction) reanalysis between 1990 and 2004. The biogeochemical processes are simulated with a carbon, Si(OH)(4), and nitrogen ecosystem (CoSiNE) model consisting of silicate, nitrate, ammonium, two phytoplankton groups (small phytoplankton and large phytoplankton), two zooplankton grazers (small micrograzers and large mesozooplankton), and two detritus pools. The ROMS-CoSiNE model favourably reproduces many of the observed features, such as ChI a, nutrients, and primary production (PP) in the SCS. The modelled depth-integrated PP over the euphotic zone (0-125 m) varies seasonally, with the highest value of 386 mg C m (-2) d (-1) during winter and the lowest value of 156 mg C m (-2) d (-1) during early summer. The annual mean value is 196 mg C m (-2) d (-1). The model-integrated annual mean new production (uptake of nitrate), in carbon units, is 64.4 mg C m (-2) d (-1) which yields an f-ratio of 0.33 for the entire SCS. The modelled export ratio (e-ratio: the ratio of export to PP) is 0.24 for the basin-wide SCS. The year-to-year variation of biological productivity in the SCS is weaker than the seasonal variation. The large phytoplankton group tends to dominate over the smaller phytoplankton group, and likely plays an important role in determining the interannual variability of primary and new production.