乙二醇降解聚2,6-萘二甲酸乙二醇酯

采用乙二醇对聚2,6-萘二甲酸乙二醇酯(PEN)进行降解,表征了醇解产物,探讨了醇解原理。结果表明:醇解后PEN中的酯键断裂,PEN分子内的蟄合羟基变成2,6-萘二甲酸乙二醇酯(BHEN)上分子间缔合羟基和游离羟基;醇解后产物的O与C的原子比由醇解前的0.28增至0.38,醇解产物中C=O和C—O两种O结构的质量比为1∶2.18,C—C、C—O和O—C=O三种C结构的质量比为5.38∶2.22∶1,产物的平均分子量降为200左右;醇解产物主要为BHEN及其低聚物,BHEN单体纯度在90%以上,收率为25.95%。该醇解反应是酯基断裂又聚合,PEN长链变短的过程。

铜(Ⅱ)离子对白腐菌Panus conchatus产木素降解酶的调控

研究了在培养基中铜离子存在以及浓度的变化对白腐首Panusconchatus产漆酶和依赖锰过氧化物酶的影响。结果表明依赖锰过氧化物酶的产生受Cu2+浓度的影响不大，而漆酶的产生却显著受CU2+的调控，没有Cu2+存在时，漆酶的活性很低，增加Cu2+浓度漆酶的活性增大，但是过多的Cu2+又会对漆酶的产生有抑制作用，使酶活降低。

废聚酯瓶制取水溶性聚酯绝缘电泳漆的研究

采用废聚酯瓶为原材料,经一系列化学反应,制得漆包线用水溶性聚酯绝缘电泳漆树脂。考察了催化剂、多元醇和酸酐的种类及用量对水溶性聚酯绝缘电泳漆的影响。

生物可降解性紫杉醇支架预防血管再狭窄的实验研究

目的 探讨生物可降解性紫杉醇支架防治血管再狭窄的作用。方法 制备“Z形”聚左旋乳酸 (PLLA)裸支架和含抗增生药物紫杉醇 6 0 μg的PLLA支架。应用 7F球囊对 8只犬肾动脉以下的腹主动脉进行 2处扩张 ,制成血管再狭窄模型。按照解剖标志分别将裸支架和紫杉醇支架置入扩张后的腹主动脉处。支架置入术后 6周处死实验犬取出标本行组织病理、形态学测量和免疫组织化学分析。结果 裸支架组血管平均管腔面积为 (775 86 5± 6 6 0 ) μm2 ;紫杉醇支架组血管平均管腔面积为 (113435 9± 71 0 ) μm2 ,紫杉醇支架组管腔平均面积大于裸支架组 (P <0 0 1)。裸支架组血管新生内膜平均增生面积为 :(2 4 80 3± 5 6 ) μm2 ;紫杉醇组平均内膜增生面积为 (12 931± 6 3) μm2 ,紫杉醇支架组新生内膜平均面积明显小于裸支架组 (P <0 0 1)。裸支架组增殖细胞核抗原 (PCNA)细胞阳性率为 (38± 15 ) % ;紫杉醇支架组为 (11± 0 31) % ,两组差异有显著性意义 (P <0 0 1)。结论 生物可降解性血管内支架作为载荷和释放药物的有效平台 ,通过携带抗增生药物紫杉醇可以显著抑制血管平滑肌细胞的增殖和血管内膜的增生 ,是防治血管再狭窄的理想手段。

Synthesis of graphene/tourmaline/TiO_2 composites with enhanced activity for photocatalytic degradation of 2-propanol

We report the construction of a graphene/tourmaline/TiO2(G/T/TiO2)composite system with enhanced charge‐carrier separation,and therefore enhanced photocatalytic properties,based on tailoring the surface‐charged state of graphene and/or by introducing an external electric field arising from tourmaline.A simple two‐step hydrothermal method was used to synthesize G/T/TiO2composites and poly(diallyldimethylammonium chloride)‐G/T/TiO2composites.In the photocatalytic degradation of2‐propanol(IPA),the catalytic activity of the composite containing negatively charged graphene was higher than of the composite containing positively charged graphene.The highest acetone evolution rate(223?mol/h)was achieved using the ternary composite with the optimum composition,i.e.,G0.5/T5/TiO2(0.5wt%graphene and5wt%tourmaline).The involvement of tourmaline and graphene in the composite is believed to facilitate the separation and transportation of electrons and holes photogenerated in TiO2.This synergetic effect could account for the enhanced photocatalytic activity of the G/T/TiO2composite.A mechanistic study indicated that O2??radicals and holes were the main reactive oxygen species in photocatalytic degradation of IPA.

Degradation of polyvinyl-alcohol wastewater by Fenton’s reagent: Condition optimization and enhanced biodegradability

The pretreatment of refractory polyvinyl-alcohol （PVA） wastewater with low value of CODcr by Fenton＇s reagent was investigated to enhance the biodegradabilily. The effects of operating conditions such as pH of the solution, Fe2＋ dosage, H2O2 dosage, reaction time and initial PVA concentration on the removal efficiency of CODCr were discussed. It is demonstrated that the optimum value of pH for removal of CODcr is 5 and the most suitable dosages of H2O2 （2%） and FeSO4 （10 mg/L） are 5% and 8.0%, respectively. When the initial CODcr value of the PVA water is 760 mg/L, the favorable reaction time is 110 min. Under these optimum conditions, the removal ratio of CODcr is 58.6% 61.4%, and the value of biodegradability （CODB/CODcr） increases markedly from 8.9% 9.7% to 62.6% 68.3%.

Feedback regulation of cholesterol synthesis： sterol-accelerated ubiquitination and degradation of HMG CoA reductase

3-Hydroxy-3-methylglutaryl coenzyme A （HMG CoA） reductase produces mevalonate, an important intermediate in the synthesis of cholesterol and essential nonsterol isoprenoids. The reductase is subject to an exorbitant amount of feedback control through multiple mechanisms that are mediated by sterol and nonsterol end-products of mevalonate metabolism. Here, I will discuss recent advances that shed light on one mechanism for control of reductase, which involves rapid degradation of the enzyme. Accumulation of certain sterols triggers binding of reductase to endoplasmic reticulum （ER） membrane proteins called Insig-1 and Insig-2. Reductase-Insig binding results in recruitment of a membrane-associated ubiquitin ligase called gp78, which initiates ubiquitination of reductase. This ubiquitination is an obligatory reaction for recognition and degradation of reductase from ER membranes by cytosolic 26S proteasomes. Thus, sterol-accelerated degradation of reductase represents an example of how a general cellular process （ER-associated degradation） is used to control an important metabolic pathway （cholesterol synthesis）.

One-pot synthesis of poly vinyl alcohol(PVA) supported silver nanoparticles and its efficiency in catalytic reduction of methylene blue

Stable silver nanoparticles were synthesized using polyvinyl alcohol （PVA） as reducing and capping agent. The method of steric stabilization was adopted for the incorporation of silver nanoparticles in the polymer matrix. The successful incorporation of silver nanoparticles in a PVA matrix was confirmed by UV–Visible spectroscopy, transmission electron microscopy （TEM） and Fourier transform infrared （FT-IR） spectroscopy. The synthesized silver nanoparticles were characterized by a peak at 426 nm in the UV–Vis spectrum. TEM studies showed the formation of spherical shaped silver nanoparticles of 10-13 nm, following the reduction by UV irradiation. Catalytic properties were studied by means of UV-Visible spectroscopic analysis. The synthesized silver nanoparticles exhibited good catalytic properties in the reduction of methylene blue.

Degradation behaviors,thermostability and mechanical properties of poly(ethylene terephthalate)/polylactic acid blends

It is difficult for polyethylene terephthalate （PET） to degrade,which caused severe pollution.In this work,polylactic acid （PLA） was introduced to improve the degradation of PET.PET/PLA was synthesized by extrusion blending.The thermal,crystalline and mechanical properties of blends were investigated with TGA,DSC,WAXD and universal testing machine.The degradation of the blends in soil,acid and alkaline buffer solutions was assessed,respectively.It was found that the introduction of a little PLA promoted crystallization of PET during injection molding process.The starting decomposition temperature lowered from 412.1 ℃ of pure PET to 330.4 ℃ at 50% PLA content,tensile and bending strength of blends gradually decreased with the PLA content increasing,while the degradation rate improved.Alkaline environment was most beneficial for blends to degrade.The degradation mechanism was discussed.

Preparation of PLA or PLGA Microspheres with Estradiol the Effects of THF—adding on the Properties of MS

Aim Polylactic acid (PLA) or polylactide-co-glycolide (PLGA) was used asbiodegradable and biocom-patible carriers to achieve sustained release ofestradial-PLGA/PLA-Microspheres (E_2-PLGA/PLA-MS). THF was added in the organic phase to study itseffects on the properties of MS. Methods MS were formed by an emulsification-solvent extractionmethod with mixture of ethyl acetate (EtoAc) and tetrahydrofuran (THF) as the organic solvents, andthen the properties and in vitro drug release behavior were examined. Results The results indicatedthat the drug loading efficiency decreased when THF added, but when the ratio of EtoAc was more than50% , there was no obvious effect of THF ratio, but the particle size increased accordingly. Thecarriers' properties and the drug contents were the main factors influencing the in vitro drugrelease. Conclusions By controlling the technology and formulation, we can get sustained-release E_2biodegradable microsperes with proper particle size, drug content and low burst-release, althoughTHF with readily solubility in water was used in the organic phase.

Mechanism of Photo-Fenton Degradation of Ethanol and PVA

Contrast degradation experiments between ethanol and polyvinyl alcohol (PVA) were conducted during H2O2, UV/H2O2, Fenton, and Photo-Fenton processes in this study. UV/VIS spectra showed' that complexes between Fe(Ⅲ) and organics were easily formed and degraded within reaction time. Compared with ,the degradation of complex, hydroxyl radicals acted weakly in Fenton or Photo-Fenton process. Hydroxyl radi'cals involved in Photo-Fenton process were deemed to be generated from the split decomposition of H2O2, photolysis of Fe_aq^3+, and degradation of hydrated Fe(Ⅳ)-complex but not traditional Fenton reaction. Experimental evidence to support this point was presented in this paper.

Biodegradation of DTP and PET Fiber by Microbe

The degradation of diethylene glycol terephthalate (DTP) and polyethylene terephthalate (PET) fiber by microbe was studied.The degree of DTP degradation was determined by High Performance Liquid Chromatography (HPLC) to be more than 90%.The products after degradation of DTP and PET fiber were various.The degradation of DTP can be described by the first-order reaction model.The degradation of PET fiber was found to be little,but surface erosion of PET fiber could be clearly seen from the SEM photographs indicating there occurred some traces of biodegradation on the PET fiber surface.

Kinetic Model of Resin-Catalyzed Decomposition of Acetone Cyanohydrin in Organic Solvent

Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with chemical catalysts and the successive operation in the bioreactor, anion exchange resin (D301) was used as catalyst for this reaction. External diffusion limitation was excluded by raising rotational speed to higher than 190r·min^-1 in both solvents. Internal diffusion limitation was verified to be insignificant in this reaction system. The effect of acetone cyanohydrin concentration on the reaction was also investigated. An intrinsic kinetic model was proposed when the mass transfer limitation was excluded, and the average deviation of the model is 10.5%.

Effects of a Biosurfactant and a Synthetic Surfactant on Phenanthrene Degradation by a Sphingomonas Strain

A novel phenanthrene (PHE)-degrading strain named as Sphingomonas sp.GF2B was isolated and identified from a farmland soil.Effects of a synthetic surfactant (Tween-80) and a rhamnolipid biosurfactant on PHE degradation by Sphin- gomonas sp.GF2B were investigated at different concentrations of the surfactants.The results showed that Sphingomonas sp.GF2B was able to mineralize up to 83.6% of PHE within 10 days without addition of surfactants.The addition of Tween-80 to the reaction medium inhibited greatly PHE biodegradation,with only 33.5% of PHE degraded.However,the biosurfactant facilitated PHE biodegradation,with up to 99.5% of PHE degraded.The preferential utilization of PHE as a carbon source and the enhanced solubility of PHE by the biosurfactant were likely responsible for the higher biodegra- dation efficiency of PHE in the presence of the biosurfactant.Therefore,it could be concluded that the application of the biosurfactant to PHE-contaminated soils was perhaps a feasible way to facilitate the PHE biodegradation.