基于属性的安全增强云存储访问控制方案

为了保证云存储中用户数据和隐私的安全,提出了一种基于属性的安全增强云存储访问控制方案。通过共用属性集,将基于属性的加密体制(ABE)与XACML框架有机结合,在XACML框架上实现细粒度的基于属性的访问控制并由ABE保证数据的机密性。考虑到数据量很大时ABE的效率较低,因此,云存储中海量敏感数据的机密性用对称密码体制实现,ABE仅用于保护数据量较小的对称密钥。实验分析表明,该方案不仅能保证用户数据和隐私的机密性,而且性能优于其他同类系统。     

全安全的属性基认证密钥交换协议

因在细粒度访问控制、定向广播等方面的广泛应用,基于属性的密码机制逐渐受到关注。以一个全安全的属性基加密(ABE)机制为基本构件,结合NAXOS技巧,提出了一个全安全的属性基认证密钥交换协议,并利用可证明安全理论在基于属性的eCK模型中进行了严格的形式化证明。相比已有的同类协议,提出的协议具有更高的安全性,并在提供丰富的属性认证策略的同时,减小了通信开销。     

Anti-inflammatory effects and chemical study of a flavonoid-enriched fraction from adlay bran

Anti-inflammation-guided fractionation and purification were used to evaluate the bioactivity and components of adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) bran. Results showed that the fraction with high phenolic and flavonoid contents from the ethanol extracts of adlay bran suppressed LPS-stimulated IL-6 and TNF-α secretions in a concentration-dependent manner in RAW 264.7 cells and murine peritoneal macrophages. Fifteen compounds, including a novel aurone derivative, two chromones, one dihydrochalcone, one chalcone, four flavanones, five flavones and one isoflavone, were isolated from the active fraction. The structure of the new compound was elucidated by spectroscopic methods, including 1D and 2D NMR and MS. All of the isolates are reported for the first time from adlay except naringenin. LC/MS was also provided as an analytical platform. Our results suggest that flavonoids in adlay bran, partially at least, contribute to its anti-inflammatory effect. Thus, adlay bran may be beneficial to the health of consumers.     

玉米丁醇生命周期温室气体排放

采用一种油井到车轮(well to wheel,WTW)的分析方法,确定生物丁醇相关WTW活动包括玉米种植、玉米的运输、丁醇生产、丁醇运输、车辆运行.采用3种不同的副产品分配方法,计算并比较了玉米丁醇在生命周期内的温室气体排放量.研究结果表明:根据能值法和产品替代法,玉米丁醇生命周期温室气体(GHG)排放量与同等热值汽油相比可以减少26.0%~49.5%;用生物丁醇联产的丙酮替代以石油为基础的丙酮,可以显著降低丁醇生命周期GHG排放量;玉米丁醇生命周期中,GHG排放的主要来源是使用天然气、柴油和氮肥,分别占到总GHG排放的53.00%、21.40%和13.38%.     

超微粉碎稻谷糠壳发酵生产燃料丁醇的研究

以超微粉碎后的稻谷糠壳为原料,以丙酮丁醇梭菌为发酵菌株,考察了不同硫酸浓度和酸水解时间对发酵生产丙酮、丁醇、乙醇（ABE）总溶剂浓度的影响。同时进一步研究其酸水解液不同脱毒方式,添加碳源和营养物质对ABE总溶剂产量的影响。结果表明：体积分数为1．5％的硫酸121℃酸水解30min,利用Ca（OH）：过中和酸水解液脱毒,发酵78h最终ABE总溶剂量为14．62g/L,较未处理提高30．10％,残糖质量浓度为8．46g／L,较未处理下降47．8％;超微粉碎后稻谷糠壳酸水解液中的营养成分已能满足丙酮丁醇梭菌发酵生产ABE溶剂所需,添加葡萄糖碳源和其他营养成分并不能显著提高ABE总溶剂产量和缩短发酵时间。     

发酵-渗透汽化连续耦合生产ABE的动力学研究

采用PDMS膜生物反应器和丙酮丁醇梭菌进行了生产ABE的封闭循环连续发酵实验,研究了发酵和渗透汽化分离连续耦合条件下的发酵动力学行为。发酵-分离连续耦合实验运行持续时间长达 192 h。运行过程中,细胞浓度维持在 0.84~4.00 g/L,发酵液中ABE的总浓度为5.14~17.54 g/L,葡萄糖浓度大约为16.08~35.15 g/L,总体积产率为0.36 g/(L?h)。实验结果表明,膜生物反应器系统运行稳定,发酵-渗透汽化分离连续耦合生产ABE的操作模式具有可行性和优越性。     

The effects of dilution rate and glucose concentration on continuous acetone–butanol–ethanol fermentation by Clostridium acetobutylicum immobilized on bricks

BACKGROUND: Owing to the rapid depletion of petroleum fuel, the production of butanol through biological routes has attracted increasing attention. However, low butanol productivity severely impedes its potential industrial production. It is known that the immobilization of whole cells can enhance productivity in the acetone‐butanol‐ethanol (ABE) continuous fermentation process. Therefore, the objective of this study was to develop a low‐cost continuous operation for butanol production. RESULTS: Bricks were chosen as cell support because of their low cost and ease of use for immobilization. The solvent productivity for the bricks with immobilized cells was 0.7 g L^?1 h^?1, 1.89 times that of free cells (0.37 g L^?1 h^?1) at a dilution rate of 0.054 h^?1. The productivity improvement can contribute to greater retention of biomass inside the reactor due to immobilization. The increase in glucose feed concentration raised total solvent production. However, it resulted in a decrease in yield (grams of solvents produced per gram of glucose introduced). Continuous operation with immobilized cells at a dilution rate of 0.107 h^?1 resulted in a solvent productivity of 1.21 g L^?1 h^?1, 2.1 times that of the operation at 0.027 h^?1. However, the yield (butanol produced per glucose consumed) was decreased to 0.19 from 0.29 under the same glucose feeding condition of 60 g L^?1. CONCLUSION: The increase in dilution rate and feed glucose concentration enhanced productivity, but decreased the utilization of substrates and the final solvent concentration. Therefore, a balance between productivity and glucose utilization is required to ensure continuous process operation. Copyright © 2011 Society of Chemical Industry     

Isolation of native Clostridia for utilization of agroindustrial cherry waste into butanol

The use of butanol synthesized from organic waste has been widely studied, but the lack of native strains of Clostridium and the use of a synthetic medium for its growth remain important barriers to extend its use. In this work, it was possible to isolate and characterize three strains of Clostridium sp. native using the Cherry Waste (ChW) as a culture medium, contained 106 g L^?1 of total carbohydrates equivalent glucose, and a synthetic medium (P2) as control containing 20 g L^?1 of glucose, which demonstrated that isolated natives strains are producers butanol, used ChW as culture medium. The work done is a contribution in the field of bioenergy science to increase the bioconversion of agroindustrial waste energy and thus reduce the costs of biofuel production.