208 research outputs found

    Enhancement of thermophilic anaerobic sludge digestion by 70ºC pre-treatment : energy considerations

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    The objective of this work was to investigate the effect of a low temperature pre-treatment (70°C) on the thermophilic anaerobic digestion of sewage sludge. Experimental results were used for the calculation of theoretical energy balances of full-scale digesters with and without pre-treatment step. The 70°C sludge pre-treatment increased sludge solubilization by 10 times and enhanced volatile fatty acids generation. Biogas production increased up to 30-40% and methane content in biogas from 64 to 68-70%. Theoretical calculations showed that additional surplus energy production would be expected by incorporating a 70°C pre-treatment step to a thermophilic reactor

    Transcriptome Sequencing and <i>De Novo</i> Analysis of Cytoplasmic Male Sterility and Maintenance in JA-CMS Cotton

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    <div><p>Cytoplasmic male sterility (CMS) is the failure to produce functional pollen, which is inherited maternally. And it is known that anther development is modulated through complicated interactions between nuclear and mitochondrial genes in sporophytic and gametophytic tissues. However, an unbiased transcriptome sequencing analysis of CMS in cotton is currently lacking in the literature. This study compared differentially expressed (DE) genes of floral buds at the sporogenous cells stage (SS) and microsporocyte stage (MS) (the two most important stages for pollen abortion in JA-CMS) between JA-CMS and its fertile maintainer line JB cotton plants, using the Illumina HiSeq 2000 sequencing platform. A total of 709 (1.8%) DE genes including 293 up-regulated and 416 down-regulated genes were identified in JA-CMS line comparing with its maintainer line at the SS stage, and 644 (1.6%) DE genes with 263 up-regulated and 381 down-regulated genes were detected at the MS stage. By comparing the two stages in the same material, there were 8 up-regulated and 9 down-regulated DE genes in JA-CMS line and 29 up-regulated and 9 down-regulated DE genes in JB maintainer line at the MS stage. Quantitative RT-PCR was used to validate 7 randomly selected DE genes. Bioinformatics analysis revealed that genes involved in reduction-oxidation reactions and alpha-linolenic acid metabolism were down-regulated, while genes pertaining to photosynthesis and flavonoid biosynthesis were up-regulated in JA-CMS floral buds compared with their JB counterparts at the SS and/or MS stages. All these four biological processes play important roles in reactive oxygen species (ROS) homeostasis, which may be an important factor contributing to the sterile trait of JA-CMS. Further experiments are warranted to elucidate molecular mechanisms of these genes that lead to CMS.</p></div

    Efficient and Environmentally Friendly Synthesis of AlFe-PILC-Supported MnCe Catalysts for Benzene Combustion

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    An efficient and environmentally friendly synthesis of AlFe-pillared clay (AlFe-PILC)-supported MnCe catalysts was explored. Mixed AlFe pillaring agents were prepared by a one-step method using Locron L and ferric nitrate solutions at a high temperature and high pressure. Montmorillonite was treated with the AlFe pillaring agents to synthesize AlFe-PILC. MnO<sub><i>x</i></sub> and CeO<sub>2</sub> with different Mn/Ce atomic ratios were loaded onto the AlFe-PILC support by an impregnation method. The catalysts were characterized using X-ray diffraction, N<sub>2</sub> adsorption, and high-resolution transmission electron microscopy–energy dispersive spectrometry and were tested for the catalytic combustion of benzene and temperature-programmed surface reaction using a microreactor. Compared to conventional methods, this method is simpler and less costly and results in a larger specific surface area, pore volume, and basal spacing, with the ability to control the structure of the catalytic materials. MnCe(6:1)/AlFe-PILC has the highest catalytic activity and can completely degrade benzene (600 ppm in air) at 250 °C. The activity of the catalyst is stable, and no obvious deactivation is observed at 230 °C after 1000 continuous hours. The catalyst is resistant to water and Cl-poisoning. The amount of CeO<sub>2</sub> added is critical to the dispersion of MnO<sub><i>x</i></sub> on the support and the creation of optimum number of oxygen vacancy defect sites for the benzene oxidation reaction. The AlFe-PILC-supported MnCe catalyst is a promising porous material; the support structure, proper dispersion of active species, and addition of Ce are essential for achieving complete degradation of organic toxic chemicals at relatively low temperatures

    Structural Transformation of Birnessite by Fulvic Acid under Anoxic Conditions

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    The structure and Mn­(III) concentration of birnessite dictate its reactivity and can be changed by birnessite partial reduction, but effects of pH and reductant/birnessite ratios on the changes by reduction remain unclear. We found that the two factors strongly affect the structure of birnessite (δ-MnO<sub>2</sub>) and its Mn­(III) content during its reduction by fulvic acid (FA) at pH 4–8 and FA/solid mass ratios of 0.01–10 under anoxic conditions over 600 h. During the reduction, the structure of δ-MnO<sub>2</sub> is increasingly accumulated with both Mn­(III) and Mn­(II) but much more with Mn­(III) at pH 8, whereas the accumulated Mn is mainly Mn­(II) with little Mn­(III) at pH 4 and 6. Mn­(III) accumulation, either in layers or over vacancies, is stronger at higher FA/solid ratios. At FA/solid ratios ≥1 and pH 6 and 8, additional hausmannite and MnOOH phases form. The altered birnessite favorably adsorbs FA because of the structural accumulation of Mn­(II, III). Like during microbially mediated oxidative precipitation of birnessite, the dynamic changes during its reduction are ascribed to the birnessite-Mn­(II) redox reactions. Our work suggests low reactivity of birnessite coexisting with organic matter and severe decline of its reactivity by partial reduction in alkaline environment

    Determining the I/O point policy in a robotic live-cube compact storage system

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    The robotic live-cube compact storage system can provide a higher storage capacity and more flexible throughput than other automated warehousing systems. The extant studies usually fix the input/output point at the bottom-left of such storage systems and have not investigated other configurations of the input/output point. In this study, we propose six policies for the configuration of the input/output point and evaluate their performance by using an analytical model and simulations. A sensitivity analysis is carried out by considering different shape-related factors, system heights, and energy consumption to explore the optimal configuration of the input/output point. For most input/output point policies, a shape factor (length divided by depth) of 0.5 results in good system performance in terms of retrieval time. When using optimal system dimension, the input/output point located in the upper-middle part along the length and depth performs best compared with other policies. Specifically, this configuration reduces the retrieval time by 40.23% and energy consumption by 42.31% compared with the bottom-left corner input/output point. We find that there exists a trade-off among the cost of setup, number of empty grids, and retrieval time when varying the number of input/output points.</p

    A Facile Bifunctional Strategy for Fabrication of Bioactive or Bioinert Functionalized Organic Surfaces via Amides-Initiated Photochemical Reactions

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    The excellent potential of organic polymeric materials in the biomedical field could be exploited if their interfacial problem could be fully resolved. A necessary prerequisite to this purpose often involves the simple but effective synthesis of a bioactive surface to endow polymer surfaces with high reactivity toward efficient biomolecules conjugation and a bioinert surface to prevent nonspecific adsorption of nontarget biomolecules. Although the corresponding research has been an important topic, actually few strategies could pave the way to comprehensively and simply tackle both of the bioactive and bioinert surfaces preparation issues. Herein we report an extremely simple and integrative bifunctional method that could efficiently tailor an organic material surface toward both bioactive and bioinert functions. This method is based on the use of an amides-initiated photochemical reaction in a confined space, which depending on the type of solutes used, results in the incorporation of primary amine groups or surface carbon radicals on an inert polymer surface. The grafted amine group could be used as a highly reactive site for biomolecule conjugation, and the surface carbon radical could be used to initiate radical graft polymerization of antifouling polymer brushes. We expect this simple but powerful method could provide a general resolution to solve the interfacial problem of organic substrate, offering a low-cost practical approach for real biomedical applications

    Venn diagram of DE gene counts at the SS and MS stages for JA-CMS and JB floral buds.

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    <p>B2 = SS stage of JA-CMS, K2 = SS stage of JB, K3 = MS stage of JB, B3 = MS stage of JA-CMS (from right to left).</p

    MOESM2 of Prophage recombinases-mediated genome engineering in Lactobacillus plantarum

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    Additional file 2: Figure S2 Inspection of ΔldhD::gusA mutants for the GusA activity

    GO analysis results of DE genes at the SS and MS stages between JA-CMS and JB.

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    <p>Notes: 1) BP = Biological process, CC = Cellular component, MF = Molecular function; Q value = FDR corrected p value. 2) Only GO categories with FDR q value ≤ 0.05 are presented here. 3) GO categories are arranged based on q values from smallest to largest at the SS stage.</p><p>GO analysis results of DE genes at the SS and MS stages between JA-CMS and JB.</p
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