Expression and molecular analysis of phbB gene in Chlamydomonas reinhardtii

The expression vector containing phbB and ble genes was constructed and transformed into cell-wall-deficient strain Chlamydomonas reinhardtii CC-849 by the glass-head method. The transgenic alga was selected and maintained in the TAP agar plates containing 10 mug/mL Zeomycin. Transgenic alga, which could express phbB at the transcriptional level, was obtained and further confirmed with PCR, Southern blot and RT-PCR-DNA hybridization analysis.

可生物降解脂肪族聚酯的反应接枝与相形态

聚（β-轻基丁酸醋-co-β-经基戊酸酷）（PHBV）是一种生物降解脂肪族聚酷，其结晶成核密度低，结晶速度比较慢且易生成大尺寸的球晶。以球晶中心向外扩展形成许多圆环状的开裂以及沿球晶生长方向形成许多劈裂，从而导致了PHBV呈脆性断裂。只要能有效地降低其结晶度，减小球晶尺寸，就可以达到增韧的目的。通过PHBV与二氧化碳一环氧丙烷共聚物（PPC）反应接枝来调控PHBV的结构和相形态，具有实际的理论意义和应用前景。开展了PPC的封端和与PHBv的接枝反应。首次提出了甲基丙烯酸缩水甘油醋（GMA）与PHBV及PPC与PHBV－GMA的接枝反应机理。确信PHBV接枝GMA的接枝点发生在PHBV骨架上的季碳原子上，反应过程中没有交联反应和降解反应的发生。发现PHBv-g-Gh1A共聚物上环氧基能与封端的PPc上的梭基熔融反应原位生成了PHBv-g-PPC共聚物。在机械共混物中两大分子之间的接枝和醋交换反应几乎不发生。GMA的引入阻止了PHBV的降解行为，从而改善了PHBV的加工性能。成功地调控了PHBVPC结构及相形态。证实了PHBV与PPC在反应共混过程中的接枝反应。加入PPC阻碍了PHBV的结晶，这在反应体系中更加明显。通过控制反应条件和反应物的组成，可以使非反应共混物中PHBV球晶变得不规则，发生扭曲变形，球晶尺寸降低；而在反应共混物中，可以使其球晶已很难辨认。SEM结果表明在PHBV用PC（30／70）和PHBV用PC（70／30）共混物中发生了相转变。尤其在反应共混物中淬断面表现为塑性。力学性能随共混组成而发生较大幅度的改变。发现通过改变组成及对反应共混相结构的控制，PHBV共混物的断裂伸长率可变化1一2个数量级，从而实现了制得一系列从脆性断裂塑料到高韧性弹性体的高分子材料。研究了反应接枝共混体系的熔融、结晶行为、等温和非等温结晶动力学。发现加入的GMA对PHBV有成核作用。引入的PPC阻碍了PHBV的结晶，降低PHBV的结晶度，球晶径向生长速率，平衡熔点和结晶能力。结晶速率与冷却速率有较大的依赖性。修正的Avrami方程能很好地描述PHBv和PHBv爪PC共混物非等温结晶过程。对动态力学性能的分析发现，反应共混物相比于非反应共混物聚合物玻璃化温度都有不同程度的内移，说明两组分间相容性增加，接枝共聚物具有良好的增容效果，显著地改善了两相界面性能。PHBV可以部分进入PPC相区，使共混物分子运动特征发生改变。发现在熔体加工条件下，PHBV与PPC之间很难发生酷交换反应，但是以辛酸亚锡为催化剂，氯苯为溶剂，在120℃条件下，两者可以发生醋交换反应。在聚己内醋（PCL）用PC熔融共混过程中GMA可以有效地抑制过氧化二异丙苯（DCP）所引起的PCL交联反应。在DCP和OMA存在下得到的样品之球晶具有十字消光现象，球晶规整度增大。同在溶液中醋交换催化剂存在下PPC和PCL发生了酷交换反应后所形成的球晶相结构相类似，而PCL／PPCOCP体系所形成的球晶中含有大量的非晶相区。从而，确信了GMA在脂肪族聚醋，脂肪族聚碳酸醋等生物降解高分子反应共混体系中的双重作用：一是引入具有高反应活性的官能团；二是减少在过氧化物作用下PHBV类高分子的降解及PCL类高分子的交联反应。PCL共混组分可以提高PPC相区的稳定性。提高反应时间或催化剂浓度同样能够改善热稳定性。

Biodegradable amphiphilic block copolymers bearing protected hydroxyl groups: Synthesis and characterization

A new biodegradable amphiphilic block copolymer, poly(ethylene glycol)-b-poly(L-factide-co-9-phenyl-2,4,8, 10-tetraoxaspiro[5,5]undecan-3-one) [PEG-b-P(LA-co-PTO)], was successfully prepared by ring-opening polymerization (ROP) Of L-lactide (LA) and functionalized carbonate monomer 9-phenyl-2,4,8,10-tetraozaspiro[5,5]undecan-3-one (PTO) in the presence of monohydroxyl poly(ethylene glycol) as macroinitiator using Sn(Oct)(2) as catalyst. NMR, FT-IR, and GPC studies confirmed the copolymer structure.

Synthesis and Stabilization of Novel Aliphatic Polycarbonate from Renewable Resource

A novel aliphatic polycarbonate from renewable resource was prepared by copolymerization of furfuryl glycidyl ether and CO2 using rare earth ternary catalyst; its number-average molecular weight (M-n) reached 13.3 x 10(4) g/mol. The furfuryl glycidyl ether and CO2 copolymer (PFGEC) was easy to become yellowish at ambient atmosphere due to post polymerization cross-linking reaction oil the furan ring; the gel content was 17.2 wt % after 24 h exposure to air at room temperature. PFGEC could be stabilized by addition of antioxidant 1010 (tetrakis[methylene (3.5-di(tert-butyl)-4-hydroxhydrocinnamate)]methane) in 0.5-3 wt % after copolymerization. The Diels-Alder (DA) reaction between N-phenylmaleimide and the pendant furan ring was also effective for the stabilization of PFGEC by reducing the amount of furan ring and introducing bulky groups into PFGEC. The cyclization degree could reach 72.1% when the molar ratio of N-phenylmaleimide to furan ring was 3: 1, and no gel was observed after 24 h exposure to air. The glass transition temperature (T-g) of PFGEC was 6.8 degrees C, and it increased to 40.3 degrees C after DA reaction (molar ratio of N-phenylmaleimide to furan ring was 3: 1).

Biodegradable amphiphilic triblock copolymer bearing pendant glucose residues: Preparation and specific interaction with Concanavalin A molecules

A novel biodegradable amphiphilic block copolymer PLGG-PEG-PLGG bearing pendant glucose residues is successfully prepared by the coupling reaction of 3-(2-aminoethylthio) propyl-R-D-glucopyranoside with the pendant carboxyl groups of PLGG-PEG-PLGG in the presence of N,N'-carbonyldiimidazole. The polymer PLGG-PEG-PLGG, i.e., poly {(lactic acid)-co-[(glycolic acid)-alt-(L-glutamic acid)]}-block-poly(ethylene glycol)-block-poly{( lactic acid)-co-[( glycolic acid)-alt-(L-glutamic acid)]}, is prepared by ring-opening copolymerization of L-lactide (LLA) with (3s)-benzoxylcarbonylethylmorpholine-2,5-dione (BEMD) in the presence of dihydroxyl PEG with molecular weight of 2000 as macroinitiator and Sn(Oct)(2) as catalyst, and then by catalytic hydrogenation. The glucose-grafted copolymer shows a lower degree of cytotoxicity to ECV-304 cells and improved specific recognition and binding with Concanavalin A (Con A). Therefore, this kind of glucose-grafted copolymer may find biomedical applications.

On-line concentration of peptides and proteins with the hyphenation of polymer monolithic immobilized metal affinity chromatography and capillary electrophoresis

An iminodiacetic acid (IDA)-type adsorbent is prepared at the one end of a capillary by covalently bonding IDA to the monolithic rods of macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate). Cu(II) is later introduced to the support via the interaction with IDA. By this means, polymer monolithic immobilized metal affinity chromatography (IMAC) materials are prepared. With such a column, IMAC for on-line concentration and capillary electrophoresis (CE) for the subsequent analysis are hyphenated for the analysis of peptides and proteins. The reproducibility of such a column has been proved good with relative standard deviations (RSDs) of dead time of less than 5% for injection-to-injection and 12% for column-to-column (n = 3). Through application on the analysis of standard peptides and real protein samples, such a technique has shown promising in proteome study.

The Heterogeneous Growth of P(3MeTh)--An Ellipsometric Study

Successive thicker P(3MeTh) layers are analysed by ex situ conventional and imaging ellipsometry. Thin films display a smooth surface, are compact and homogeneous while for a growth charge above 20 mC cm(-2) the polymer structure modifies to a still uniform but less dense layer. A two-layer model is used and a mathematical procedure is developed to obtain, simultaneously, from the experimental ellipsometric parameters, Delta and Psi, the thickness and the complex refractive index of P(3MeTh) films grown up to 80 mC cm(-2). Thicker polymer layers are disordered and present a high degree of surface roughness. 

植物生产生物可降解塑料PHB的研究：真养产碱杆菌H16的phbB和phbC的基因克隆、植物表达载体构建和转基因马铃薯植株的获得

利用聚合酶链式反应(PCR)技术从Alcaligenes eutrophus H16染色体DNA中扩增并克隆了调控聚-3-羟基丁酸(poly-3-hydroxy-butyrate，PHB)生物合成的两个关键酶基因：依赖NADPH的乙酰乙酰CoA还原酶基因(phbB)和PHB合成酶基因(phbC)。限制性内切酶图谱和核苷酸序列分析证实了克隆结果，并表明克隆的基因与国外所报道的有很高的同源性。经过基因拼接，构建了块茎特异性表达的高等植物表达载体pPSAGB（嵌合phbB）、pBIBGC(嵌合phbC)和pPSAGCB（嵌合phbB和phbC）。并以试管薯(microtuber)为外植体经Agrobacterium介导转化了虎头、京丰、Bintje、Favorita、高原4号和88-5共6个马铃薯品种，获得49个株系。经PCR检测导入phbB的株系共有44个，对其中30个株系进行DNA dot blot分析，结果表明phbC导入呈阳性的株系有20个。深入的鉴定工作还在进行中。

Fabrication of ZnO and its enhancement of charge injection and transport in hybrid organic/inorganic light emitting devices

ZnO nanocrystals were synthesized by hydrolysis in methanol. X-ray diffraction and photoluminescence spectra confirm that good crystallized ZnO nanoparticles were formed. Utilizing those ZnO nanoparticles and poly [2- methoxy-5 - (3',7'-dimethyloctyloxy)- 1,4-phenylenevinylene] (MDMO-PPV), light emitting devices with indium tin oxide (ITO)/poly(3,4-oxyethyleneoxy-thiophene):poly(styrene sulfonate) (PEDOT:PSS)/ ZnO:MDMO-PPV/Al and ITO/PEDOT:PSS/MDMO-PPV/Al structures were fabricated. Electrolummescence (EL) spectra reveal that EL yield of hybrid MDMO-PPV and ZnO nanocrystals devices increased greatly as compared with pristine MDMO-PPV devices. The current-voltage characteristics indicate that addition of ZnO nanocrystals can facilitate electrical injection and charge transport. The decreased energy barrier to electron injection is responsible for the increased efficiency of electron injection. (c) 2007 Elsevier B.V. All rights reserved.

Enhanced photoresponse from the ordered microstructure of naphthalocyanine-carbon nanotube composite film

Naphthalocyanine-sensitized multi-walled carbon nanotube (NaPc-MWNT) composites have been synthesized through the pi-stacking between naphthalocyanine (NaPc) and carbon nanotubes. The resultant nanocomposites were characterized with a scanning electron microscope (SEM), a transmission electron microscope (TEM), and by UV - vis absorption and photocurrent spectra. The long-range ordering was observed in the NaPc - MWNT composites by using a TEM. The enhancement in the absorption intensity and the broadening of the absorption wavelength observed in the composite films, which were due to the attachment of NaPc on the MWNT surface, is discussed based on the measured UV - vis absorption spectra. Furthermore, the photoconductivity of the poly( 3-hexylthiophene)(PAT6) - NaPc - MWNT composite film was found to increase remarkably in the visible region and broaden towards the red regions. These new phenomena were ascribed to the larger donor/acceptor (D/A) interface and the formation of a biconsecutive D/A network structure, as discussed in consideration of the photoinduced charge transfer between PAT6 and NaPc - MWNT.

Broadband short-range surface plasmon structures for absorption enhancement in organic photovoltaics

We theoretically demonstrate a polarization-independent nanopatterned ultra-thin metallic structure supporting short-range surface plasmon polariton (SRSPP) modes to improve the performance of organic solar cells. The physical mechanism and the mode distribution of the SRSPP excited in the cell device were analyzed, and reveal that the SRSPP-assisted broadband absorption enhancement peak could be tuned by tailoring the parameters of the nanopatterned metallic structure. Three-dimensional finite-difference time domain calculations show that this plasmonic structure can enhance the optical absorption of polymer-based photovoltaics by 39% to 112%, depending on the nature of the active layer (corresponding to an enhancement in short-circuit current density by 47% to 130%). These results are promising for the design of organic photovoltaics with enhanced performance.

Phase transition behavior and molecular orientation of oligo(9,9 '-dioctylfluorene-alt-bithiophene)

A novel conjugated oligomer, oligo(9,9'-dioctylfluorene-alt-bithiophene) (OF8T2), was found to exhibit a unique phase transition between crystalline and liquid-crystalline states, and a liquid-crystalline glass was easily generated, offering better TFT device performance. In thin films, upon annealing the OF8T2 molecules oriented preferentially with their planes of conjugation being normal to the substrate, and both film thickness and annealing temperature were critical to the film morphology and the molecular orientation. When the OF8T2 film was deposited on a rubbed polyimide surface and annealed, the molecules aligned their long axes along the rubbing direction.

Improving performance of polymer photovoltaic devices using an annealing-free approach via construction of ordered aggregates in solution

Low crystalline order has been proved to be one of the main hindrances for achieving high performance devices based on thin films composed of crystallizable polymer. In this work, we use a facile method to substantially improve crystallinity of poly(3-hexylthiophene) (P3HT) in its pure or composite film via the construction of ordered precursors in the solution used for thin film deposition. These improvements have been confirmed by bright-field transmission electron micrography, electron diffraction, UV-Vis absorption and wide-angle X-ray diffraction.