Polylactic acid as a biodegradable material for all-solution-processed organic electronic devices

In this paper we report on the fabrication of spin-coated biodegradable polylactic acid (PLA) thin films to be used as substrates for the realisation of all-solution-processed organic electronic devices. The full mechanical and electrical characterisation of these substrates shows that they exhibit good mechanical and dielectric properties and are therefore suitable for the fabrication of disposable electronics. To demonstrate practically the functionality of such PLA thin films, organic electronic devices were realised on the top of them, exclusively by means of solution-process fabrication techniques and in particular inkjet-printing. Also, a photonic curing procedure is here presented as a means for sintering the conductive inks without heating up the PLA substrates. Two types of organic transistors were fabricated on the top of PLA: organic field-effect transistors (OFETs), where the PLA film was used not only as a substrate but also as the gate dielectric, and all-inkjet-printed organic electrochemical transistors (OECTs). The second typology of transistors exhibited one of the highest transconductance reported so far in the literature (up to 2.75 mS). This study opens an avenue for the fabrication of disposable, low-cost organic electronic devices.     

氢氧化钠/尿素法和硫酸法测定烟草木质素的对比分析

为了对比氢氧化钠/尿素法(NU法)和硫酸法在测定烟草中木质素含量(质量分数,下同)的差异性,采用NU法和硫酸法测定广东、四川、湖南、云南和贵州5个产区烟梗和烟叶的木质素含量,分析了两种方法在预处理过程的干扰物质去除率及酸解过程木质素含量和结构变化。结果表明:1与硫酸法相比,NU法预处理对干扰物质的去除率更高。2NU法采用稀酸酸解,减少了烟草中木质素的降解;选择在325 nm处测定酸溶木质素(ASL)的紫外吸光度,避免了蛋白质和糠醛对ASL的干扰,提高了烟草木质素测定结果的准确度和重现性。3与硫酸法相比,NU法分离得到的酸不溶木质素(AIL)的氧化程度低、结构变化小,因而更能反映烟草木质素的结构特征。NU法比硫酸法更加适用于烟草木质素的含量测定。     

A new insight into the adsorption mechanism of patulin by the heat-inactive lactic acid bacteria cells

The primary objective of this study was to identify the characteristics of the heat-inactived lactic acid bacteria (LAB) cells involved in the adsorption of patulin. The bacterial cells were characterized by Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM-EDS), Transmission Electron Microscopy (TEM) and Brunauer–Emmett–Teller (BET) technique. The patulin-exposed bacterial cells and patulin-unexposed bacterial cells were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Zeta Potential and Contact Angle Method. It was found that Lactobacillus brevis 20023 (LB-20023), which has the highest specific surface area and cell wall volume, showed the highest capacity to adsorb patulin from the aqueous solution. Five major elements (C, N, O, P, and S) were detected by SEM-EDS, and LB-20023 displayed the highest nitrogen-to-carbon (N/C) ratio (0.2938). LB-20023 exhibited the highest hydrophobicity, but the zeta potential was not prominent compared to other bacterial cells. The main functional groups involved in adsorbing patulin were C–O, OH and/or NH groups, suggesting that polysaccharides and/or protein were important functional components. Above all, the adsorption capacity of bacterial cells had close relationships with physical and chemical properties of cell surface, including specific surface area, cell wall volume, nitrogen-to-carbon (N/C) ratio, hydrophobicity and functional groups. Further study will be needed to find other additional functional factors.     

Mutagenic Effects of Iron Oxide Nanoparticles on Biological Cells

In recent years, there has been an increased interest in the design and use of iron oxide materials with nanoscale dimensions for magnetic, catalytic, biomedical, and electronic applications. The increased manufacture and use of iron oxide nanoparticles (IONPs) in consumer products as well as industrial processes is expected to lead to the unintentional release of IONPs into the environment. The impact of IONPs on the environment and on biological species is not well understood but remains a concern due to the increased chemical reactivity of nanoparticles relative to their bulk counterparts. This review article describes the impact of IONPs on cellular genetic components. The mutagenic impact of IONPs may damage an organism’s ability to develop or reproduce. To date, there has been experimental evidence of IONPs having mutagenic interactions on human cell lines including lymphoblastoids, fibroblasts, microvascular endothelial cells, bone marrow cells, lung epithelial cells, alveolar type II like epithelial cells, bronchial fibroblasts, skin epithelial cells, hepatocytes, cerebral endothelial cells, fibrosarcoma cells, breast carcinoma cells, lung carcinoma cells, and cervix carcinoma cells. Other cell lines including the Chinese hamster ovary cells, mouse fibroblast cells, murine fibroblast cells, Mytilus galloprovincialis sperm cells, mice lung cells, murine alveolar macrophages, mice hepatic and renal tissue cells, and vero cells have also shown mutagenic effects upon exposure to IONPs. We further show the influence of IONPs on microorganisms in the presence and absence of dissolved organic carbon. The results shed light on the transformations IONPs undergo in the environment and the nature of the potential mutagenic impact on biological cells.     

黏胶生产中含硫尾气的半干法制酸装置

介绍了半干法制酸工艺原理和工艺流程。在某黏胶生产线上运用半干法制酸装置处理来自酸浴的8 000 Nm3/h和来自纺丝的4 8000 Nm3/h湿性废气,通过补充硫磺3.3 t/h,可以生产硫酸300 t/d,吨酸回收1.65 t蒸汽。半干法制酸装置具有腐蚀性小、副产蒸汽多、电耗低、投资省、维护量少等优点。     

Surface Treatment of ZrO2 Nanoparticles with Biosafe Citric Acid and Its Utilization for the Synthesis of L-leucine Based Poly(Amide–Imide) Nanocomposites

This study aimed at preparing three nanocomposites of optically active poly(amide–imide) and zirconium dioxide (ZrO₂) inorganic nanoparticles through the ultrasonic process. First, the surface of ZrO₂ nanocomposites was chemically modified with bio-active citric acid in the basic media. Then, the poly(amide–imide) was reinforced with modified nanocomposites and three poly(amide–imide)/ZrO₂-citric acid nanocomposites were synthesized by ultrasonic irradiation. The poly(amide–imide) was prepared by polycondensation of N-trimellitylimido-L-leucine with 4,4′-diaminodiphenylsulfone using of triphenyl phosphite and molten tetra-n-butylammonium bromide as green media. The obtained poly(amide–imide)/ZrO₂-citric acid nanocomposites were characterized by different techniques.     

Identification of antifungal peptides produced by Lactobacillus plantarum IS10 grown in the MRS broth

The use of secondary metabolites of lactic acid bacteria for preservation of foods is increasingly gaining interest to the food industry to replace synthetic preservatives. In this study, the cell free supernatant containing peptides obtained from Lactobacillus plantarum IS10 was fractionated by size exclusion chromatography using sephadex G-25, and tested against Aspergillus flavus MD3, Penicillium roqueforti MD4 and Eurotium rubrum MD5. Among the fractions, fraction number 10 showed 60% antifungal activity at a concentration of 0.02 mg peptide/mL. Four novel peptides out of twenty peptides obtained from fraction 10 were identified and determined by de novo sequencing. Peptide FPSHTGMSVPPP with a net charge +1, hydrophobicity ratio 58% and molecular weight of 1253 was further studied. The selected peptide showed a good activity at a concentration of 5 mg/mL against selected fungi and poor activity at low concentrations. This work indicates that L. plantarum IS10 has the capability of producing peptides which are affective against spoilage fungi.     

Antibacterial mechanism of lactic acid on physiological and morphological properties of Salmonella Enteritidis,Escherichia coli and Listeria monocytogenes

Lactic acid is widely used to inhibit the growth of important microbial pathogens, but its antibacterial mechanism is not yet fully understood. The objective of this study was to investigate the antibacterial mechanism of lactic acid on Salmonella Enteritidis, Escherichia coli and Listeria monocytogenes by size measurement, TEM, and SDS-PAGE analysis. The results indicated that 0.5% lactic acid could completely inhibit the growth of Salmonella Enteritidis, E. coli and L. monocytogenes cells. Meanwhile, lactic acid resulted in leakage of proteins of Salmonella, E. coli and Listeria cells, and the amount of leakage after 6 h exposure were up to 11.36, 11.76 and 16.29 μg/mL, respectively. Measurements of the release of proteins and SDS-PAGE confirmed the disruptive action of lactic acid on cytoplasmic membrane, as well as the content and activity of bacterial proteins. The Z-Average sizes of three pathogens were changed to smaller after lactic acid treatment. The damaged membrane structure and intracellular structure induced by lactic acid could be observed from TEM images. The results suggested that the antimicrobial effect was probably caused by physiological and morphological changes in bacterial cells.