De novo transcriptome assembly of Aureobasidium melanogenum CGMCC18996 to analyze theβ-poly(L-malic acid)biosynthesis pathway under the CaCO_(3) addition

β-Poly(L-malic acid)(PMLA)is a water-soluble biopolymer used in food,medicine and other industries.To date,the biosynthesis pathway of PMLA has not been fully elucidated.In this study,we sequenced the transcriptom e of strain Aureobasidium melanogenum under 20 g/L CaCO_(3) addition.The resulting sequencing reads were assembled and annotated for the differentially expressed genes(DEGs)analysis and novel transcripts identification.The result indicated that with the CaCO_(3) addition,the tricarboxylic cycle(TCA)cycle and glyoxylate pathway were up-regulated,and it also found that a non-ribosomal peptide synthetase(NRPS)like protein was highly expressed.The DEGs analysis showed a high expression level of malate dehydrogenase(MDHC)and phosphoenolpyruvate carboxykinase(PCKA)in the CaCO_(3) group,which indicated a cytosolic malate activity.We speculated that the malate should be transported to or synthesized in the cytoplasm,which was then polymerized to PMLA by the NRPS-like protein,accompanied by the up-regulated TCA cycle providing ATP for the polymerization.Depending on the analysis,we assumed that an NRPS-like protein,the TCA cycle,and the cytosolic malate together are contributing to the PMLA biosynthesis.

Synthesis and Hydrophilic Performance of Poly(Lactic Acid)-Poly(Ethylene Glycol) Block Copolymers

Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and 1H nuclear magnetic resonance (1H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA.

High-gravity technology intensified Knoevenagel condensation-Michael addition polymerization of poly (ethylene glycol)-poly (n-butyl cyanoacrylate) for blood-brain barrier delivery

Poly(ethylene glycol)-poly(n-butyl cyanoacrylate)(PEG-PBCA)is a remarkable drug delivery carrier for permeating blood-brain barrier.In this work,a novel high-gravity procedure was reported to intensify Knoevenagel condensation-Michael addition polymerization of PEG-PBCA.A series of PEG-PBCA containing different block ratios were synthesized with narrow molecular weight distribution of polydispersity indexes less than 1.1.Furthermore,the reaction time reduced 60%compared to conventional stirred tank reactor process.Chemical structures of as-prepared polymers were characterized.In vitro drug delivery performance was evaluated.The cytotoxicity of PEG-PBCA to brain microvessel endothelial cells(BMVEC)decreases with the extension of the PEG chain and the shortening of the PBCA chain.The polymer cellular uptake to BMVECs was better after improving hydrophilicity by PEG block.Results of bloodbrain barrier permeability demonstrated that medium length of PBCA chain and short PEG chain are favorable for hydrophobic Nile red permeation,while long PEG chain and short PBCA chain are beneficial to delivery water-soluble doxorubicin hydrochloride(Dox).The average apparent permeability coeffi-cient increased 1.7 and 0.25 times than that of raw Nile red and Dox,respectively.High-gravity intensi-fied condensation polymerization should have great potential in brain drug delivery system.

Photodegradation Behavior of Polycaprolactone-Poly(ethylene glycol)Block Copolymer

The biodegradation behavior in vitro and in vivo of polycaprolactone-poly (ethylene glycol) block copolymer (PCE) was reported in detail. In this paper, photodegradation test of PCE was performed by exposure to UV light. The mechanical properties and the inherent viscosity of PCE samples which are subjected to photodegradation were determined. The experimental results indicated that poly (ethylene glycol) (PEO) segment in PCE copolymer is photosensitive. The photodegra-dation rate of the PCE was increased with increasing poly (ethylene glycol) content.

Mechanical, Thermal and Morphology Properties of Thermoplastic Polyurethane Copolymers Incorporating α,ω-Dihydroxy-[poly(propyleneoxide)-poly (dimethylsiloxane)-poly(propyleneoxide)] of Varying Poly(propyleneoxide) Molecular Weight

Novel segmented thermoplastic polyurethane (TPU) copolymers were synthesized using two-step solventless bulk polymerization. 4,4’-methylenediphenyl diisocyanate (MDI) and 1,4-Butanediol (BDO) were used to form hard segment of TPU and α,ω-dihydroxy-[poly(propyleneoxide)-poly (dimethylsiloxane)-poly(propyleneoxide)] (α,ω-dihydroxy-(PPO-PDMS-PPO)) was used to form soft segment of TPU, where the molar ratio of the –N=C=O/OH was 1.02 and the hard segment weight percentage was 30%. A series of TPUs were characterized by fourier transform infrared spectroscopy (FT-IR). The investigation of triblock oligomer’s PPO molecular weight impact on the derived TPU’s mechanical properties, thermal performance, surface water repellency and morphology performance was carried by Instron material tester, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), water contact angles (WCA), scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDX) and wide angle X-ray diffraction (WAXD), respectively. FT-IR confirmed α,ω-dihydroxy-(PPO-PDMS-PPO) well cooperating into urethane structure and analyzed hydrogen bonding between N-H group with hard segment C=O group and N-H group with soft segment C-O-C group. DSC and WAXD results showed α,ω-dihydroxy-(PPO-PDMS-PPO) segments crystallization. SEM-EDX results showed that the presence of a spherulitic morphology, which arose from the crystallization of the PPO segments. The thermal properties measured by TGA and DSC were slightly affected by molecular weight of PPO and microphase separation. The weight loss of TPUs started between 294°C and 300°C, and Tg was in the range of -70°C to -107°C. TPU copolymers’ surface hydrophobicity property was excellent with WCA range of 95°?to 112°. TPU-3 with 1000 molecular weight PPO has the optimized mechanical properties with tensile strength 16.4 MPa and the modulus at 100% elongation 6.2 MPa and elongation 398%.

The Influence of Trans-1,4-poly(butadiene-co-isoprene) Copolymer Rubbers(TBIR) with Different Molecular Weights on the NR/TBIR Blends

The molecular weight of a polymer is of prime importance and greatly influences the processing and mechanical properties of the polymer. Trans-1,4-poly(butadiene-co-isoprene) multi-block copolymer rubbers(TBIR) exhibit outstanding fatigue resistance, low heat build-up and good abrasion resistance, and are expected to be desirable candidate for high performance tire. Study on the influence of TBIR with different molecular weights on the structure and properties of TBIR and natural rubber(NR)/TBIR blends is essential to understand its contribution to the greatly improved dynamic properties of the rubber vulcanizates. TBIR with different molecular weights characterized by 1H-NMR, 13C-NMR, GPC, and DSC were highly trans-1,4-copolymers with similar chain sequence distribution and crystalline trans-1,4-polyisoprene(TPI) blocks. The green strength and modulus of TBIR increased with the increasing molecular weight.The NR/TBIR compounds filled with 40 phr carbon black were chemically cured by sulfur for the preparation of NR/TBIR vulcanizates.The compatibility between NR and TBIR, filler distribution, crosslinking bond and density, and properties of NR/TBIR vulcanizates were studied. The NR/TBIR vulcanizates showed increasing tensile strength, hardness, modulus, rebound, abrasion resistance, and flexural fatigue properties with increasing molecular weight of TBIR. Furthermore, they presented significant improvement in flexural fatigue resistance when compared with that of NR vulcanizate. The contribution mechanism of TBIR on the NR/TBIR blends was discussed. The TBIR with a wide range of molecular weight are ideal rubbers for high performance tires.

Combination of hydrophobically modified γ-poly(glutamic acid)and trehalose achieving high cryosurvival of RBCs

Trehalose is expected to be an alternative for toxic glycerol as a biocompatible cryoprotectant of red blood cells(RBCs).In this work,γ-poly(glutamic acid)(PGA)is modified by grafting hydrophobic phenethylamine,3,4-dimethoxyphenylethylamine and dodecylamine,respectively.The graft-modified PGA can significantly enhance cryosurvival of RBCs in combination with trehalose.Analyses of dynamic light scattering,hemolysis assay,atomic force microscope and confocal laser scanning microscope suggest that the modified PGA polymers can self-assemble into nanoparticles in phosphate buffer saline solutions at the pH range of 6.0–7.4,and exhibit membrane-disruptive activity due to hydrogen bond,conjugation and hydrophobic interactions with cell membranes.It is assumed that the modified PGA polymers can improve the cryosurvival of RBCs by promoting membrane permeability of trehalose.Among the three graft-modified polymers,phenethylamine-grafted PGA(PGA-g-PEA)can significantly increase the intracellular trehalose-loading content to 11.3±2.4 m M at pH 7.4,much higher than the value0.17±0.66 m M when trehalose is used without any polymers.In view of the aforementioned merit,the cryosurvival rate of sheep RBCs is increased to about 90%by incubation with 1.0 mg mL-1 PGA-g-PEA and 0.36 M trehalose.In vitro cell culture of L929 fibroblasts demonstrates low cytotoxicity of PGA-g-PEA.Therefore,hydrophobic PEA-modified PGA with enhanced intracellular trehalose-loading ability can be potentially applied in glycerol-free RBC cryopreservation or other related biomacromolecule delivery systems.

Synthesis of poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine) and preparation of its hydrogel solution containing doxorubicin

Many pH-and temperature-responsive polymers have been designed for preparing hydrogel.In the present study,in order to decrease the pH sensitivity of reported poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine)(PAA1580-PEG4600-PAA1580),we designed and synthesized poly(amidoamine)-poly(ethyleneglycol)-poly(amidoamine)(PAA-PEG-PAA)with shorter length of PAA chain by decreasing reaction temperature for preparing PAA-PEG-PAA hydrogel solution containing doxorubicin(DOX).The PAA-PEG-PAA was synthesized via the Michael-addition polymerization.The characteristic of PAA-PEG-PAA was evaluated.The PAA-PEG-PAA hydrogel solution was prepared and investigated.DOX-loaded PAA-PEG-PAA hydrogel solution was prepared,and its in vitro DOX release and in vitro anti-tumor activity were evaluated.Our results indicated that the viscosity of PAA-PEG-PAA hydrogel solution was concentration-and temperature-dependent.The sol-gel transition temperature of PAA-PEG-PAA hydrogel solution(12%,w/w)ranged from 35 to 29℃,and its pH ranged from 6.0 to 7.4.The released DOX from DOX-loaded PAA-PEG-PAA hydrogel showed sustained release characteristics.The in vitro anti-tumor activity of DOX-loaded PAA-PEG-PAA hydrogel was confirmed in B16 F10 cell line.Considering the acidic tumor microenvironment,this DOX-loaded PAA-PEG-PAA hydrogel solution would be easy in situ administration for intra-tumor injection or para-tumor injection forming hydrogel at body temperature.We suggested that this DOX-loaded PAA-PEG-PAAhydrogel solution,if containing photothermal conversion agents,would have a potential further use for photothermal therapy.

Scale-up Efficient Synthesis of α-Poly(L-lysine)

α-Poly(_(L)-lysine)(α-PLL)is a water-soluble cationic biopolymer containing the monomeric unitα-_(L)-lysine,which not only possesses excellent intrinsic properties but also can be modified via facile reactions between the side amine groups and many other functional moieties.Ring-opening polymerization(ROP)is the most prevalently used technique for the synthesis of PL_(L)-based polypeptides,which involves initial conversion of theε-primary amine-protectedα-_(L)-lysine to the _(L)-lysine NCA monomer.However,obtaining N-carboxyanhydrides(NCAs)in high purity has been a formidable challenge for over 50 years,let alone the large-scale synthesis.Herein,we show an unprecedented scale-up synthesis of _(L)-Cbz-LysNCA monomer and its polymers,generating linearα-poly(_(L)-lysine)with molecular weight(MW)up to 13.4 kDa.This easy operated scale-up strategy will lay the foundations for the industrial preparation of _(L)-Cbz-LysNCA and its polymers,and further extend the realm of existing applications,offering a paradigm for scale-up synthesis of other polypeptides.

不同表面活性剂在盐酸介质中对钢的缓蚀协同效应

用失重法研究了在盐酸介质中,十二烷基苯磺酸钠(DBSAS)和非离子表面活性剂聚乙二醇辛基苯基醚(OP)对钢的缓蚀协同效应,讨论了产生协同效应的原因。

EVOH/PE-HD共混相容性研究

使用三种功能化改性的聚乙烯作为相容剂改善EVOH /PE HD共混体系的相容性 ,研究了共混体系的热性能和力学性能。SEM表明 ,相容共混体系中形成了高度分散和牢固的界面结合 ,二甲苯萃取实验和IR分析证实了相容性的改善来自于EVOH与相容剂之间的化学反应。相容共混体系中EVOH作为分散相时其结晶温度明显降低 ,结晶速度放慢 ;共混物中两组分的结晶熔点均低于纯组分。这些均可归因于体系更好的相容性以及强烈的界面作用。相容共混体系的力学性能较之简单共混体系得到明显改善 ,EVOH为分散相时拉伸强度提高幅度较大(5 0 % ) ,而在PE HD为分散相时缺口冲击强度的增幅达到 3 0 %。

药用辅料研究新进展——生物可降解聚合物

近年来 ,生物可降解聚合物在药物传递系统研究领域越来越受瞩目 ,部分聚合物已应用于各种剂型。本文综述了壳聚糖、聚酯类、嵌段共聚物、阳离子聚合物、聚合物 药物、智能聚合物等研究的最新进展及其在药学领域的应用。

涤纶金属化纤维的结构与性能研究

采用化学镀镍的方法制备金属化导电纤维。用扫描电镜 (SEM)、X射线衍射法、光电子能谱仪 (XPS)等分析金属化纤维的结构 ,并对其性能进行研究。结果表明 ,镀镍金属化纤维表面分布着均匀致密的金属层 ,且具有良好的导电性、耐洗性和热牢度。

FABRICATION AND AFM/FFM STUDIES OF C_(60)-CONTAINING POLYELECTROLYTE SELF-ASSEMBLED FILMS

An initial investigation on the roughness and frictional properties of the self-assembled thin films from polyelectrolytes is presented. Star-shaped C-60-Poly(styrene-maleic anhydride) was successful prepared. The multilayer thin films have been fabricated on mica with diazoresin as the cationic polyelectrolyte and hydrolyzed star-shaped C-60-poly(styrene-maleic anhydride) as the anionic polyelectrolyte via self-assembly technique. The crosslinking structure of the films is formed from the conversion of ionic bond to covalent bond after UV irradiation. AFM/FFM investigations provide insights into the roughness and frictional properties on a microscale. The roughness depends strongly on the number of film layers in the case of C-60-containing films. The frictional forces of the films exhibited a well behaved non-linear relationship in response to the change of applied load. It supports the prediction of enhanced load-bearing property Of C60-containing thin films.

Co-delivery of resveratrol and docetaxel via polymeric micelles to improve the treatment of drug-resistant tumors

Co-delivery of anti-cancer drugs is promising to improve the efficacy of cancer treatment.This study was aiming to investigate the potential of concurrent delivery of resveratrol(RES)and docetaxel(DTX)via polymeric nanocarriers to treat breast cancer.To this end,methoxyl poly(ethylene glycol)-poly(D,L-lactide)copolymer(mPEG-PDLA)was prepared and characterized using FTIR and 1H NMR,and their molecular weights were determined by GPC.Isobologram analysis and combination index calculation were performed to find the optimal ratio between RES and DTX to against human breast adenocarcinoma cell line(MCF-7 cells).Subsequently,RES and DTX were loaded in the mPEG-PDLA micelles simultaneously,and the morphology,particle size distribution,in vitro release,pharmacokinetic profiles,as well as cytotoxicity to the MCF-7 cells were characterized.IC50 of RES and DTX in MCF-7 cells were determined to be 23.0μg/ml and 10.4μg/ml,respectively,while a lower IC50 of 4.8μg/ml of the combination of RES and DTX was obtained.The combination of RES and DTX at a ratio of 1:1(w/w)generated stronger synergistic effect than other ratios in the MCF-7 cells.RES and DTX loaded mPEG-PDLA micelles exhibited prolonged release profiles,and enhanced cytotoxicity in vitro against MCF-7 cells.The AUC(0→t)of DTX and RES in mPEG-PDLA micelles after i.v.administration to rats were 3.0-fold and 1.6-fold higher than that of i.v.injections of the individual drugs.These findings indicated that the co-delivery of RES and DTX using mPEG-PDLA micelles could have better treatment of tumors.

PU与PE在家具与室内装饰应用中应注意的几个问题

国内木器用高档涂料主要有聚氨酯漆(PU)和聚酯漆(PE)两大类,指出了这两种涂料的主要区别,并指出了施工中主要注意的问题。

涤纶织物的溶胶-凝胶法易清洁整理

以正硅酸乙酯水解缩聚,无水乙醇为共溶剂,氨水为催化剂,采用溶胶-凝胶法制备溶胶,并用十二烷基三甲氧基硅烷和γ-甲基丙烯酰氧基丙基三甲氧基硅烷作为硅烷偶联剂,对溶胶进行原位改性。优化的配方为:正硅酸乙酯∶水∶氨水∶无水乙醇的物质的量之比为1∶5∶4∶10,加入质量分数为3%的十二烷基三甲氧基硅烷和0.20 mol/L硅烷偶联剂对其进行改性。整理后涤纶织物的拒水和抗污等级均达到5级。

掺加纤维的乳化沥青冷再生混合料路用性能及机理分析

随着乳化沥青冷再生混合料逐渐在高等级公路高层位路面结构的应用，其抗裂性和抗疲劳耐久性需要引起高度的重视，基于加速加载、SCB、间接拉伸疲劳试验研究了纤维乳化沥青冷再生混合料的抗裂性和抗剪切变形能力，同时基于扫描电镜试验分析了聚酯纤维改性乳化沥青混合料破坏界面细微观形貌，揭示了纤维对乳化沥青冷再生混合料的路用性能的影响机理，推荐了乳化沥青冷再生混合料适宜的聚酯纤维掺量为2‰-3‰。

阻燃型辐射制冷涂层涤纶织物的性能

辐射制冷涂层涤纶织物的开发有助于实现物体主动降温,降低能源消耗。聚氨酯涂层涤纶织物易燃,且在燃烧过程中产生熔滴,使用过程中有潜在的火灾危害性。针对上述问题,采用磷酸酯阻燃剂DTZR-1607和DTFR-8000对辐射制冷涂层涤纶织物进行阻燃改性。结果表明:当阻燃剂DTZR-1607、DTFR-8000的质量比为6∶2,阻燃剂质量分数为6%,阻燃涂层织物增重100 g/m^(2)时,涂层涤纶织物可获得较好的阻燃性能,满足阻燃纺织品B1级标准。

涤纶织物的防水整理

探讨了防水整理工艺对涤纶织物拒水效果的影响,分析了不同助剂的残留对拒水效果,以及防水加工对织物颜色的影响。结果表明,160℃定形60 s,防水剂Uniproof E-01质量分数为1.5%时,涤纶织物喷淋等级评分为95分,静态接触角达到136.67°。阴离子型助剂的残留会降低织物的拒水效果。防水剂处理前后染色织物颜色性能差异较小。