聚乳酸类复合材料研究进展

综述了近年来聚乳酸类生物可降解高分子复合材料的研究进展，骨修复作为其主要应用领域，未来聚乳酸类复合材料的研究有两方面值得关注：一方面需要通过无机增强材料（尤其是磷酸盐类无机钙质陶瓷成分）的粒径微细化和有机成分进行“内增强”，提高复合材料的强度，另一方面，需要通过填料的加入，使复合材料进一步功能化，特别是利用填料的碱性或药物作用，减少聚乳酸类基体降解引起的炎症。     

中国煤系气共生成藏作用研究进展

煤系气共生共探与共采受到我国天然气行业的高度关注,勘探与开发试验已经取得了一定的成效。在分析煤系气地质条件特殊性的基础上,从煤系砂岩储层致密化机理、煤系气共生组合及成藏要素配置、煤系含气系统叠置性等方面,评述了我国煤系气共生成藏作用的研究进展。研究结果表明:(1)煤系气地质条件的特殊性表现在3个方面——煤系气赋存态和储层岩石类型具有多样性,其成藏效应与常规砂岩气有所不同;煤系沉积序列旋回性极强,气、水分布关系复杂多变;煤系砂岩储集体在广覆式泥质岩中镶嵌展布。(2)煤系富有机质特性以及烃源岩生气过程产生的有机酸,是煤系砂岩储层致密化的重要诱因,煤系砂岩气可能具有部分自生自储及吸附气的成藏特点,并可在一定程度上改善砂岩储层的物性。(3)煤系沉积特点决定了煤系气成藏效应主要取决于生烃强度、运移方式与输导体系、地层流体能量、区域有效盖层等4个方面,特殊的输导体系使得烃源岩生成的天然气在复杂的源储系统中得以重新分配,这是煤系气共生成藏的重要基础。(4)含气系统叠置性是煤系气地质研究的前缘方向之一,近年来发展了测井响应识别技术和含气系统叠置性判识方法,发现煤系存在3种典型流体压力曲线类型,并初步应用于煤系气共采有利层段的优选。     

基于3D多尺度特征融合残差网络的高光谱图像分类

深度学习中用于训练的高光谱图像(HSI)数据十分有限,因此较深的网络不利于空谱特征的提取.为了缓解该问题,文中提出3D多尺度特征融合残差网络,利用深度学习和多尺度特征融合的方式对光谱-空间特征进行有序的学习.首先对3D-HSI数据进行自适应降维,将降维后的图像作为网络输入.然后,通过多尺度特征融合残差块依次提取光谱-空间特征,融合不同尺度的特征,通过特征共享增强信息流,获得更丰富的特征.最后以端到端的方式训练网络.在相关数据集上的测试表明,文中网络具有良好的分类性能.     

Mono‐Estolide Synthesis from trans‐8‐Hydroxy‐Fatty Acids by Lipases in Solvent‐Free Media and Their Physical Properties

Pseudomonas aeruginosa 42A2 is known to produce two hydroxy‐fatty acids, 10(S)‐hydroxy‐8(E)‐octadecenoic and 7,10(S,S)‐dihydroxy‐8(E)‐octadecenoic acids, when cultivated in a mineral medium using oleic acid as a single carbon source. These compounds were purified, 91 and 96 % respectively, to produce two new families of estolides: trans‐8‐estolides and saturated estolides from the monohydroxylated monomer. trans‐8‐estolides were produced by three different lipases (Novozym 435, Lipozyme RM IM and Lipozyme TL IM) with reaction yields between 68.4 ± 2.1 and 94.7 ± 2.4 % in a solvent‐free medium at 80 °C in 168 h under vacuum. Novozym 435 was found to be the most efficient biocatalyst for both hydroxy‐fatty acids with reaction yields of 71.7 ± 2.3 and 94.7 ± 2.4 %, respectively. Moreover, saturated estolides were also produced from a saturated 10(S)‐hydroxy‐8(E)‐octadecenoic. These estolides were chemically and enzymatically synthesized with Novozym 435, under the previous described reaction conditions with yields of 60.7 ± 2.1 and 71.2 ± 2.3 % respectively. Finally, viscosity, glass transition temperature, decomposition temperatures and enthalpies were determined to characterize both types of estolides. Thermal applications for both types of polyesters were improved since glass transition temperatures were lowered and decomposition temperatures were increased, with respect to their corresponding substrates.     

从贫锰矿中提取钪的试验研究

试验采用化学处理方法，通过硫酸浸出、浸出液萃取、有机相提取钪，萃取余液回收钴镍，净化液制碳酸锰。获得粗钪品位Ｓｃ２Ｏ３９６．７５％，回收率７５．５７％；钴镍混合精矿回收率８０％；碳酸锰含锰４３．７３％，回收率９０％。     

Dynamic modelling of anaerobic digestion

The anaerobic digestion model presented here considers a two step process. First, acidogenic bacteria convert glucose into acetate then methanogenic bacteria convert this acid into methane and carbon dioxide. The biomass and metabolite production rates are described by distinct relations. Therefore, there is not a direct relationship between the growth and the energy production related to metabolite formation. The inhibitory effects of the unionized acid concentration on growth rate of both bacterial populations and the methane production from acetate were considered separately. The model was tested in batch cultures with two types of organic loads, i.e. pea bleaching wastewaters and a synthetic substrate containing sucrose and organic acid. The model allowed to simulate satisfactorily the methane production under very different operational conditions.     

Selective Enzymatic Transformation to Aldehydes in vivo by Fungal Carboxylate Reductase from Neurospora crassa

The enzymatic reduction of carboxylic acids is in its infancy with only a handful of biocatalysts available to this end. We have increased the spectrum of carboxylate‐reducing enzymes (CARs) with the sequence of a fungal CAR from Neurospora crassa OR74A (NcCAR). NcCAR was efficiently expressed in E. coli using an autoinduction protocol at low temperature. It was purified and characterized in vitro, revealing a broad substrate acceptance, a pH optimum at pH 5.5–6.0, a T_m of 45 °C and inhibition by the co‐product pyrophosphate which can be alleviated by the addition of pyrophosphatase. The synthetic utility of NcCAR was demonstrated in a whole‐cell biotransformation using the Escherichia coli K‐12 MG1655 RARE strain in order to suppress overreduction to undesired alcohol. The fragrance compound piperonal was prepared from piperonylic acid (30 mM) on gram scale in 92 % isolated yield in >98% purity. This corresponds to a productivity of 1.5 g/L/h.

     

The solvent extraction of nickel from acidic solutions using synergistic mixtures containing pyridinecarboxylate esters. Part 2: Systems based on alkylsalicylic acids

The synergistic solvent extraction of nickel and cobalt by pyridinecarboxylate esters (2-, 3- or 4-C₅H₄N.CO.OR) in admixture with 3-bromo- or 3-nitro-derivatives of 5-alkylsalicylic acids was studied. Nickel is extracted more strongly than cobalt in all cases and, for systems containing a given pyridinecarboxylate, the pH₅₀ values (pH values for 50% extraction) of both metals decrease in the order: alkylsalicylic acid > bromo-derivative > nitro-derivative. For systems containing a given salicylic acid, the separation between the pH₅₀ values for nickel and cobalt was found to increase in the order: pyridine 2-ester < 4-ester ≈ 3-ester. The extractability of divalent base metals from sulphate solutions by mixtures of isodecyl 3- or 4-pyridinecarboxylate and 3-bromo- or 3-nitro-5-nonylsalicylic acid in Shellsol K decreases through the series: Cu > Ni > Co ≈ Zn > Ca > Mg. In single-stage batch extraction experiments with a simulated leach liquor containing Ni 2·2, Cu 0·5, Ca 0·4 and Mg 5·0 g dm⁻³ (and smaller amounts of other base metals), adjustment of the equilibrium pH value to between 3·3 and 4·0 with magnesium oxide gave extractions of nickel and copper of 97–100%, with co-extractions of calcium and magnesium of <0·5 and <0·1%, respectively. Amongst the metals present in lower concentrations, manganese (2–5%) and lead (5–10%) were extracted only slightly whereas cobalt (40–80%), zinc (15–65%) and iron (100%) were more strongly extracted.     

气相色谱法测定食品油脂中的十八碳反式脂肪酸

反式脂肪酸是在油脂的加氢反应或高温精炼过程中伴随产生的一类不饱和脂肪酸,过多的食用这些成分可能会对人体健康产生危害。食品油脂中以十八碳反式脂肪酸最为常见。采用气相色谱法对食品中十八碳反式脂肪酸的检测进行了实验摸索,获得了一套准确度高、精确度好的方法,可应用于日常监督检测。     

The Discrepancy of Fatty Acid Composition of Astaxanthin Esters and Total Fatty Acids in Photoautotrophic and Heterotrophic Chlorella zofingiensis

Chlorella zofingiensis has great potential for astaxanthin and fatty acid production. This study investigated the accumulation of astaxanthin and total fatty acids (TFA), the fatty acid compositions of astaxanthin esters and TFA in photoautotrophic and heterotrophic C. zofingiensis, respectively. The results displayed that in photoautotrophic cells, 18:3 was the most predominant fatty acid, followed by 16:0, 18:2, and 18:1, while astaxanthin mono-esters (mono-AE) contained only 16:0 and 18:0, and astaxanthin di-esters (di-AE) contained 16:0 mostly, followed by 18:1, 18:0, 18:2, and 18:3. C. zofingiensis accumulated the highest level of astaxanthin and TFA under heterotrophic conditions fed with 30 g L⁻¹ glucose. The percentage of 18:1 in TFA, mono-AE, and di-AE increased from 10.05%, 0%, and 17.76% to 35.80%, 14.84%, and 50.12%, respectively; in contrast, the percentages of 18:3 in TFA and di-AE were observed to decrease from 40.42% and 7.59% to 9.56% and 1.30%, respectively, in comparison with those in photoautotrophic ones. The RNA sequencing (RNA-seq) results showed that the expressions of the genes in astaxanthin and fatty acid biosynthetic pathways were increased under this heterotrophic condition. These results indicated differential accumulation of AE and TFA, especially fatty acid compositions of TFA and AE in photoautotrophic and heterotrophic cells, suggesting a positive correlation between astaxanthin and fatty acid biosynthesis.