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891.
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Dong‐Bo Ou Hong‐Juan Lang Rui Chen Xiong‐Tao Liu Qiang‐Sun Zheng 《BioEssays : news and reviews in molecular, cellular and developmental biology》2009,31(2):246-252
Biological pacemakers can be achieved by various gene‐based and cell‐based approaches. Embryonic stem cells (ESCs)‐derived pacemaker cells might be the most promising way to form biological pacemakers, but there are challenges as to how to control the differentiation of ESCs and to overcome the neoplasia, proarrhythmia, or immunogenicity resulting from the use of ESCs. As a potential approach to solve these difficult problems, tissue‐engineering techniques may provide a precise control on the different cell components of multicellular aggregates and the forming of a construct with‐defined architectures and functional properties. The combined interactions between ESC‐derived pacemaker cells, supporting cells, and matrices may completely reproduce pacemaker properties and result in a steady functional unit to induce rhythmic electrical and contractile activities. As ESCs have a high capability for self‐renewal, proliferation, and potential differentiation, we hypothesize that ESCs can be used as a source of pacemaker cells for tissue‐engineering applications and the ambitious goal of biological cardiac pacemakers may ultimately be achieved with ESCs via tissue‐engineering technology. 相似文献
894.
Ronghai He X. Philip Ye Burton C. English Justinus A. Satrio 《Bioresource technology》2009,100(21):5305-5311
The poor and inconsistent physicochemical properties of bio-oil are inhibiting its industrialized production. We investigated the variability in properties of switchgrass bio-oil produced at three pyrolysis temperatures (T = 450, 500, and 550 °C) and three feedstock moisture contents (MC = 5%, 10%, and 15%) in a 3 × 3 factorial experiment in order to exploit opportunities to improve bio-oil properties through optimization of pyrolysis parameters. Results showed that even with the single type of feedstock and pyrolysis system, the two main factors and their interaction caused large variations in bio-oil yield and most of the measured physicochemical properties. Following improvements of bio-oil properties could be individually achieved by selecting an optimal pyrolysis condition (shown in parenthesis) comparing with the worst case: increase of bio-oil yield by more than twofold (MC = 10%, T = 450 °C), increase of pH by 20.4% from 2.74 to 3.3 (MC = 10%, T = 550 °C), increase of higher heating value by 18.1% from 16.6 to 19.6 MJ/kg (MC = 10%, T = 450 °C), decrease of density by 5.9% from 1.18 to 1.11 g/cm3 (MC = 5%, T = 550 °C), decrease of water content by 36% from 31.4 to 20.1 wt.% (MC = 5%, T = 450 °C), decrease of viscosity by 40% from 28.2 to 17 centistokes (MC = 5%, T = 550 °C), decrease of solid content by 57% from 2.86 to 1.23 wt.% (MC = 15%, T = 550 °C), and decrease of ash content by 41.9% from 0.62 to 0.36 wt.% (MC = 15%, T = 550 °C). There is no single, clear-cut optimal condition that can satisfy the criteria for a bio-oil product with all the desired properties. Trade-offs should be balanced according to the usage of the end-products. 相似文献
895.
This study involved the use of terrestrial plant extracts as substitutes for toxic chemicals to control the major fouling organisms of mangroves, the barnacles. In terms of the solvents used to obtain the plant crude extracts, ethyl acetate was best, ethyl alcohol next and pure water worst, except in the case of Allium cepa (AC), where pure water was better than ethyl alcohol. For different plants, different solvents resulted in different poisonous effects, and plants belonging to different classes showed different levels of activities. In particular, using ethyl acetate crude extracts, Allium sativum (AS), AC and Capsicum annuum (CA) caused massive death of barnacle larvae at a low concentration in the shortest time. The less poisonous organic solvents were able to extract more active materials, and this was advantageous in enhancing the effect. For pure water crude extracts, AC and Zingiber officinale were best, but for 95% ethyl alcohol crude extracts, AS and AC were best. For ethyl acetate crude extracts, the effects of AS, AC and CA were better. Different solvent extracts of AC with 12 h of exposure all had LC50 values <100 mg/L. The concentrations of the effective plant crude extracts used were close to, or even lower than, those used for pesticides referred to in the literature. 相似文献
896.
Lithium Batteries: Highly Nitridated Graphene–Li2S Cathodes with Stable Modulated Cycles (Adv. Energy Mater. 23/2015) 下载免费PDF全文
897.
Drastic Layer‐Number‐Dependent Activity Enhancement in Photocatalytic H2 Evolution over nMoS2/CdS (n ≥ 1) Under Visible Light 下载免费PDF全文
Kun Chang Mu Li Tao Wang Shuxin Ouyang Peng Li Lequan Liu Jinhua Ye 《Liver Transplantation》2015,5(10)
Exploiting noble‐metal‐free cocatalysts is of huge interest for photocatalytic water splitting using solar energy. As an efficient cocatalyst in photocatalysis, MoS2 is shown promise as a low‐cost alternative to Pt for hydrogen evolution. Here we report a systematical study on controlled synthesis of MoS2 with layer number ranging from ≈1 to 112 and their activities for photocatalytic H2 evolution over commercial CdS. A drastic increase in photocatalytic H2 evolution is observed with decreasing MoS2 layer number. Particularly for the single‐layer (SL) MoS2, the SL‐MoS2/CdS sample reaches a high H2 generation rate of ≈2.01 × 10?3m h?1 in Na2S–Na2SO3 solutions and ≈2.59 × 10?3m h?1 in lactic acid solutions, corresponding to an apparent quantum efficiency of 30.2% and 38.4% at 420 nm, respectively. In addition to the more exposed edges and unsaturated active S atoms, valence band–XPS and Mott–Schottky plots analysis indicate that the SL MoS2 has the more negative conduction band energy level than the H+/H2 potential, facilitating the hydrogen reduction. 相似文献
898.
Hanjie?Li Chenlin?Ye Ke?Liu Hanqi?Gu Weitao?Du Jie?BaoEmail author 《Bioprocess and biosystems engineering》2015,38(1):149-154
Particle size of lignocellulose materials is an important factor for enzymatic hydrolysis efficiency. In this study, corn stover was milled and sieved into different size fractions from 1.42, 0.69, 0.34, to 0.21 mm, and the corresponding enzymatic hydrolysis yields were 24.69, 23.96, 25.34, and 26.97 %, respectively. The results indicate that the hydrolysis yield is approximately constant with changing corn stover particle sizes in the experimental range. The overall surface area and the inner pore size measurement show that the overall specific surface area was less than 2 % with the half reduction of particle size due to the greater inner pore surface area. The scanning electron microscope photographs gave direct evidence of the much greater inner pore surface area of corn stover particles. This result provided a reference when a proper size reduction of lignocellulose materials is considered in biorefining operations. 相似文献
899.
900.
Hong‐Hui Cui Hong‐Ze Liao Yu Tang Xin‐Yu Du Li‐Qun Chen De Ye Xue‐Qin Zhang 《植物学报(英文版)》2015,57(12):1003-1016
In flowering plants, the male and female gametogenesis is a crucial step of sexual reproduction. Although many genes have been identi fied as being involved in the gametogenesis process, the genetic mechanisms underlying gametogenesis remains poorly understood. We reported here characterization of the gene, ABORTED GAMETOPHYTE 1(AOG1) that is newly identi fied as essential for gametogenesis in Arabidopsis thaliana. AOG1 is expressed predominantly in reproductive tissues including the developing pollen grains and ovules. The AOG1 protein shares no signi ficant amino acid sequence similarity with other documented proteins and is located mainly in nuclei of the cells. Mutation in AOG1 caused degeneration of pollen at the uninucleate microspore stage and severe defect in embryo sacs, leading to a signi ficant reduction in male and female fertility.Furthermore, the molecular analyses showed that the aog1 mutant signi ficantly affected the expression of several genes, which are required for gametogenesis. Our results suggest that AOG1 plays important roles in gameto genesis at the stage prior to pollen mitosis I(PMI)in Arabidopsis, possibly through collaboration with other genes. 相似文献