类人胶原蛋白基因工程菌高密度发酵过程控制

目的优化基因工程菌Escherichia coli BL 21生产人源型胶原蛋白的高密度发酵工艺。方法建立一套以溶解氧浓度和比生长速率为中心的控制策略,采用溶氧反馈或pH反馈调节补料速度。结果 OD600可达150,胶原蛋白的表达量为9g／L。结论 20％-30％饱和度的溶解氧和0．1- 0．2 h-1的比生长速率有利于细胞生长和产物表达,其与降低乙酸等有害代谢副产物的积累密切相关。     

马来酸酐接枝SBS及其对PA6的增容作用

通过加入复合抗氧剂A(酚类)、B(亚磷酸酯类)及流动改性剂(液体石蜡)，采用热引发熔融接枝法制备马来酸酐接枝SBS，获得了具有较高接枝率(054％)和较好熔体流动性，且不含凝胶的马来酸酐接枝SBS产物。用该产物增韧PA6，获得了较好的增韧效果。     

马来酸酐接枝聚丙烯流变性及可纺性的研究

通过毛细管流变仪测定了马来酸酐接枝聚丙烯(PP-g-MAH)在高温(230～260℃)高剪切速率(100～1500s^-1)下的流变性能，并在熔融纺丝机上研究了该接枝共聚物的可纺性。结果表明PP-g-MAH的剪切粘度在低剪切速率时比PP高，在高剪切速率时则低。PP-g-MAH的粘流活化能比PP的稍高，且随接枝率的增加而增大。马来酸酐接枝聚丙烯在250～260℃具有良好的可纺性。     

Bio‐based comb‐like copolymers derived from alkyl 10‐undecenoates and maleic anhydride

In this article, 10‐undecenoic acid, based on castor oil, was used a raw material for the synthesis of alternating copolymers. ω‐Unsaturated fatty esters as alkyl 10‐undecenoates were prepared by the esterification reaction of 10‐undecenoic acid with alkyl alcohol. A series of comb‐like copolymers were synthesized by free radical polymerization from maleic anhydride and alkyl 10‐undecenoates copolymers with different length of alkyl side chains in a toluene solution. These copolymers were investigated by ¹H and ¹³C nuclear magnetic resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry (DSC). The copolymers were obtained in a low molecular weight in a range 3370–12,240 g mol⁻¹ and their structural characterization indicated the formation of alternating copolymers. DSC characterization revealed that these comb‐like copolymers showed amorphous to semicrystalline behavior by increasing the length of side chains. The bio‐based comb‐like copolymers allow for the development of new polymeric materials for several applications. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1039–1045     

Identification of markers of thermal processing (“roasting”) in aqueous extracts of Coffea arabica L. seeds through NMR fingerprinting and chemometrics

Roasting of Coffea arabica L. seeds gives rise to chemical reactions that produce more than 800 compounds, some being responsible for the desired organoleptic properties for which the beverage called “coffee” is known. In the industry, the “roasting profile,” that is, the times and temperatures applied, is key to influence the composition of roasted coffee beans and the flavour of the beverage made from them. The impact of roasting on the chemical composition of coffee has been the subject of numerous studies, including by nuclear magnetic resonance (NMR) spectroscopy. However, the roasting equipment and profiles applied in these studies are often far from real industrial conditions. In this work, the effects of two critical technological parameters of the roasting process, namely, the “development time” (the period of time after the “first crack,” a characteristic noise due to seed disruption) and the final roasting temperature on coffee extracts, were investigated. Seeds were roasted at pilot scale according to 13 industrial roasting profiles and extracted in D₂O. The extracts were analysed by ¹H NMR experiments. The NMR spectra were compared using (a) quantitative analysis of main signals by successive orders of magnitude and (b) chemometric tools (principal component analysis, partial least squares and sparse-orthogonal partial least squares analysis). This allowed to identify compounds, which may serve as markers of roasting and showed that changes in chemical composition can be detected even for slight change in final temperature (~1°C) or in total roasting time (~25 s).     

Improved Synthesis and Structure of 3-Carboxy-2-pyrazinecarbohydroxamic Acid

3-Carboxy-2-pyrazinehydroxamic acid was prepared by a one pot reaction starting from pyrazine-2,3-dicarboxylic anhydride with a high yield, and characterized by IR, Mass spectrum, 1H NMR and 13C NMR spectra and single-crystal X-ray diffraction. It crystallizes in triclinic, space group Pī with a=4.8659(10), b=7.4233(15), c=11.602(2), α=96.904(2), β=92.422(3), γ=107.454(2)°, V=395.51(14)3 , Z=2, Dc=1.689g/cm3 , F(000)=208, μ(MoKα)=0.149 mm-1 , the final R=0.0473 and wR=0.1306 for 2853 observed reflections (I>2σ (I)). A three-dimensional framework was assembled through intermolecular hydrogen bonding between water and 3-carboxy-2-pyrazine-carbohydroxamic acid molecules.     

Synthesis and Absorption Properties of Some 4-Thioaryl-1,8-naphthalimides and 4-Thioaryl-7H-benzimidazo-[2,1-a]-benz-[d,c]-isoquinolin-7-one Derivatives

A series of novel 4-thioaryl-1,8-naphthalimide derivatives were synthesized using 4-chloro-1,8-naphthalic anhydrid and arylthioles as starting materials. 4-thioaryl-1,8-naphthalic anhydride was treated with different primary amines and o-phenylene diamine or 1,2-diaminoethene to produce 4-thioaryl-1,8-naphthalimides and 4-thioaryl-7 H-benzimidazo-[2,1-a]-benz-[d,c]-isoquinolin-7-one derivatives, respectively. The UV/VIS absorption properties are discussed.     

N,N ′-Diiodo-N,N′-1,2-ethanediylbis(p-toluenesulfonamide) as an Efficient Catalyst for Acetylation of Alcohols,Phenols, Amines,and Thiols Under Solvent-Free Conditions

N,N′-Diiodo-N,N′-1,2-ethanediylbis(p-toluenesulfonamide) (NIBTS) is a highly efficient catalyst for the acetylation of alcohols, phenols, amines, and thiols under solvent-free conditions. Primary, secondary, tertiary alcohols; phenols; amines; and thiols can be easily acetylated in good to excellent yields at 80 °C.     

Rearrangements in Spiro-λ4-sulfane Chemistry

The reactions of possible spiro-λ⁴-sulfane precursor diaryl sulfoxides with dehydrating agents have been studied resulting in the formation of cyclic anhydride, spiro-λ⁴-sulfane, cyclic sulfonium-ylide, lactam-sulfoxide, cyclic sulfonimide and cyclic sulfilimine type of intermediates or products. The structures of the intermediates or products depend on the functional groups attached to the aryl rings at ortho positions and on the reaction conditions applied.     

THERMOPLASTIC ELASTOMERS. II. POLY(ETHER-ESTER-IMIDE)S BASED ON 1,4-DIAMINOBUTANE,TRIMELLITIC ANHYDRIDE, 1,4-DIHYDROXYBUTANE,AND POLY(ETHYLENE OXIDE)S

A series of new poly(ether-ester-imide)s, PEEIs, was prepared from an imide dicarboxylic acid based on 1,4-diaminobutane and trimellitic anhydride. This imide dicarboxylic acid polycondensed with 1,4-dihydroxybutane formed the hard segments and poly(ethylene oxide), PEO-1000, or mixtures of PEO-1000 and poly(tetramethylene oxide), PTMO-1000, were used as soft segments. Whenever PTMO-1000 was used as comonomer, macrophase separation was observed at the end of the polycondensation. However, this macrophase separation had little influence on the mechanical properties. A poly(ether-esterimide), PEEI, containing neat PEO-1000 was characterized by dynamic mechanical thermoanalysis, stress-strain and hysteresis measurements, and by melt rheology. The mechanical properties were compared with those of an analogous PEEI containing neat PTMO-1000 and with those of a poly(ether-ester), PEE, based on poly(butylene terephthalate) hard segments and PTMO-1000.