Stabilization of Hydroxynitrile Lyases from Two Variants of Passion Fruit,Passiflora edulis Sims and Passiflora edulis Forma flavicarpa,by C-Terminal Truncation

Because the synthesis of chiral compounds generally requires a broad range of substrate specificity and stable enzymes, screening for better enzymes and/or improvement of enzyme properties through molecular approaches is necessary for sustainable industrial development. Herein, the discovery of unique hydroxynitrile lyases (HNLs) from two species of passion fruits, Passiflora edulis forma flavicarpa (yellow passion fruit, PeHNL-Ny) and Passiflora edulis Sims (purple passion fruit, PeHNL-Np), isolated and purified from passion fruit leaves is reported. These are the smallest HNLs (comprising 121 amino acids). Amino acid sequences of both enzymes are 99 % identical; there is a difference of one amino acid in a consensus sequence. PeHNL-Np has an Ala residue at position 107 and is nonglycosylated at Asn105. Because it was confirmed that natural and glycosylated PeHNL-Ny showed superior thermostability, pH stability, and organic tolerance to that of PeHNL-Np, it has been speculated that protein engineering around the only glycosylation site, Asn105, located at the C-terminal region of PeHNL-Ny, might contribute to the stabilization of PeHNL. Therefore, the focus is on improved stability of the nonglycosylated PeHNL by truncating its C-terminal region. The C-terminal-truncated PeHNLΔ₁₀₇ was obtained by truncating 15 amino acids from the C terminus followed by expression in Escherichia coli. PeHNLΔ₁₀₇ expressed in E. coli was not glycosylated, and showed improved thermostability, solvent stability, and reusability similar to that of the wild-type glycosylated form of PeHNL expressed in Pichia pastoris. These data reveal that the lack of the high-flexibility region at the C terminus of PeHNL might be a possible reason for improving the stability of PeHNL.     

A stiffness parameter and truncation error criterion for adaptive path following in structural mechanics

We explore a truncation error criterion to steer adaptive step length refinement and coarsening in incremental-iterative path following procedures, applied to problems in large-deformation structural mechanics. Elaborating on ideas proposed by Bergan and collaborators in the 1970s, we first describe an easily computable scalar stiffness parameter whose sign and rate of change provide reliable information on the local behavior and complexity of the equilibrium path. We then derive a simple scaling law that adaptively adjusts the length of the next step based on the rate of change of the stiffness parameter at previous points on the path. We show that this scaling is equivalent to keeping a local truncation error constant in each step. We demonstrate with numerical examples that our adaptive method follows a path with a significantly reduced number of points compared to an analysis with uniform step length of the same fidelity level. A comparison with Abaqus illustrates that the truncation error criterion effectively concentrates points around the smallest-scale features of the path, which is generally not possible with automatic incrementation solely based on local convergence properties.     

层拉平技术在地震解释中的深化应用

从地震解释角度看，层拉平是一种古地表重建技术。由于技术本身的局限性，地震层拉平无法精确恢复倾斜地层厚度、压实地层厚度和地层水平伸缩量。为此，从地震层拉平的技术原理出发，首先将该技术与其他恢复技术进行对比、分析，然后通过增加地质条件约束或对原有技术方案进行改进，最大限度地降低恢复误差对恢复结果的影响，使地震层拉平技术更好地应用于地震解释的各个环节。并得出如下结论：①在楔状层序顶、底界面夹角小于15°、地层间隔厚度小于1000m的条件下，可利用沿层切片近似代替地层切片预测薄储层； ②当不整合面上、下地层压实作用差异较小时，可先利用地震层拉平技术恢复剥蚀地层厚度，进而利用修正的残余厚度法恢复古地貌；③对于一般地区而言，恢复主成藏期的古构造形态不用再做压实校正，在提高恢复精度的同时，也增强了古构造恢复的油气地质意义；④针对构造变形不甚强烈地区，可利用地震层拉平技术近似代替平衡剖面分析构造演化。这些结论可进一步促进地震层拉平技术在油气勘探领域中的深化应用。     

Variability in seismic response of secondary systems due to uncertain soil properties

A mode acceleration formulation is presented to investigate the variability in the response of a secondary system which is supported on a flexible-base primary system at multiple attachment points. The response functions are considered to be uncertain due to uncertainties in the values of shear wave velocity and Poisson’s ratio of the foundation soil. Both soil parameters are assumed to be statistically independent variables with Gaussian distributions. A numerical study with the help of an example primary-secondary (P–S) system shows that dynamic response should be ignored only for very stiff secondary modes, say > 7 times as stiff as the dominant mode of the primary system, for the proposed formulation to work well. It is also seen that uncertainty in shear wave velocity can be ignored in case of limited soil-structure interaction, while uncertainty in Poisson’s ratio should be considered only when soil damping is sensitive to the Poisson’s ratio and there is significant soil-structure interaction.     

型钢混凝土柱轴压比限值研究

型钢混凝土结构是现今高层建筑中经常采用的结构形式.为了保证地震时型钢混凝土柱的延性,<型钢混凝土组合结构技术规程JGJl38-2001)类似钢筋混凝土柱并考虑了型钢的作用规定了型钢混凝土柱的轴压比限值,但没有很好地反映轴压比限值实际应是柱界限破坏时的轴压比.经研究,建议仍可采用钢筋混凝土柱轴压比的定义并根据界限破坏推导了型钢混凝土柱轴压比限值的计算公式.     

基于能量法的强夯频域分析

强夯分析一般基于时域,利用能量方法,在频域中对强夯作用下地基动力响应进行研究与计算。由于地基模态密集,提出以能量响应信息的收敛作为模态截断的判断指标,建立能量范数和能量判据,计算强夯动力响应的模态截断阶数。根据能量方程研究强夯过程中地基应变能和动能的响应规律,研究结果表明大量的夯击能都转变为波动能量,可以认为除了表层土直接受夯锤的冲击力作用外,深层土主要是受波动影响。     

走向平衡——经济全球化背景下城市规划法比较研究

分析了经济全球化背景下我国城市规划法比较研究的概况 ,指出其存在的忽视西方城市规划法律的差别性和发展趋势 ,淡漠中国法律传统和现实国情 ,不注重国内行政法学者的研究成果 ,缺乏必要的法学实践四方面的不足。进而对西方两大法系城市规划法的历史和现状展开探讨 ;同时结合中国传统和国情 ,着重论述了我国行政法学者提出的“平衡模式” ,并就城市规划法在实践中如何实现“平衡模式”提出如下建议 :加强规划执法力度 ,发扬非权力性行政方式 ,完善行政救济制度 ,促进对行政相对人的研究     

超Bent函数的性质和构造

借助置换的性质,找到了布尔函数是超bent函数的充要条件以及超bent函数与PS 类bent函数的关系.给出了多输出超bent函数的一般构造方法,并利用这种方法构造了具有高非线性度的平衡多输出函数.     

走向园区的绿色建筑——深圳湾科技生态园的绿色实践

通过深圳市科技生态园项目绿色实践,探索大型城市园区类项目在绿色设计方法、技术体系和设计管理方面的突破和创新。项目以系统观的"平衡规划"为理论基础,以"垂直城市,立体分层"为核心规划思想,以"生态诊断+专项规划+本体技术"新的绿色园区设计流程指导,并创新集成协同的管理方法在绿色园区的设计上进行了一些有益的探索。     

用于高速微弱光信号的平衡探测技术研究

长距离高速微弱光电探测技术在激光通信中应用广泛。为了在未被噪声湮没的环境中检测出所需的微弱信号,采用平衡探测技术对单管探测和平衡探测进行对比,并且对具体的平衡探测器电路进行了理论分析和仿真,得出了在一致性系数较大(k>0.6)时平衡探测器的信噪比优于单管探测的结论。从理论上分析了单管和双管探测的最小可探测光功率。结果表明,把平衡探测技术用于高速微弱光信号探测具有很大的优越性。