Single-Base Pair Genome Editing in Human Cells by Using Site-Specific Endonucleases

Genome-wide association studies have identified numerous single-nucleotide polymorphisms (SNPs) associated with human diseases or phenotypes. However, causal relationships between most SNPs and the associated disease have not been established, owing to technical challenges such as unavailability of suitable cell lines. Recently, efficient editing of a single base pair in the genome was achieved using programmable site-specific nucleases. This technique enables experimental confirmation of the causality between SNPs and disease, and is potentially valuable in clinical applications. In this review, I introduce the molecular basis and describe examples of single-base pair editing in human cells. I also discuss the challenges associated with the technique, as well as possible solutions.     

Efficiency of exciton dissociation at internal organic interfaces beyond harmonic approximation

Understanding the mechanism of the efficient exciton dissociation in multicomponent systems belongs to the most prominent challenges in applied soft-matter physics. The model with discrete dipoles along the internal interface between the different material components is often considered as promising to account for the exciton dissociation. However, the dissociation efficiency in the framework of this model has been so far calculated only within the harmonic approximation. In the current article we calculate the dissociation efficiency in the dipolar model beyond the harmonic approximation and show that the exciton dissociation probability appears drastically larger than assumed so far. We also consider the effect of a finite spatial extent of the dipole charges and show that if the charges cannot be treated as point-like species, harmonic approximation is not applicable.     

基于云模型的水利现代化评价方法与应用

从防洪除涝减灾、水资源保障、水环境与河湖生态保护、农村水利保障、供排水工程、水管理服务以及水利发展保障7个方面建立了水利现代化水平评价指标体系,共27项指标,确定了各项指标的评价等级与标准,构建云模型对江苏省新沂市水利现代化水平进行了评价。结果表明,新沂市水利现代化水平在2015年现状的评价值分别为85.53(云模型)和84.56(集对分析),均处于基本现代化阶段,与实际情况相符;而2020年评价值为93.71(云模型)和91.38(集对分析),预测能达到全面现代化,与"十三五"规划目标相符,验证了云模型评价方法的有效性和适用性。     

Lewis Pair Polymerization of Acrylic Monomers by N-Heterocyclic Carbenes and B(C6F5)3

This work has uncovered the first highly active and efficient Lewis pair polymerization (LPP) system based on N-heterocyclic carbene (NHC)/B(C₆F₅)₃ pairs for converting acrylic monomers into medium- to high-molecular weight polymers. The study has systematically examined steric and electronic effects of three 1,3-dialkyl(Me, ⁱPr, ^tBu)imidazol-2-ylidene NHCs on the LPP of three classes of acrylic monomers, including linear methyl methacrylate (MMA), cyclic biorenewable γ-methyl-α-methylene-γ-butyrolactone (_γMMBL), and difunctional allyl methacrylate (AMA). For MMA polymerization, IⁱPr is not only the most active (∼3× and ∼120× more active than IMe and I^tBu, respectively), but also the most effective NHC, especially under low NHC loading conditions. Kinetic results are consistent with a bimolecular, activated monomer propagation mechanism. In the case of the more reactive _γMMBL, the polymerization by NHC/B(C₆F₅)₃ in CH₂Cl₂ is extremely rapid, with all three NHCs achieving quantitative monomer conversion in 1 min and thus reaching a high turnover frequency of≥48,000 h⁻¹. The molecular weight (MW) of P_γMMBL can be tuned by adjusting the [_γMMBL]/[NHC] ratio, and thus high MW polymers with relatively narrow MW distributions can be readily synthesized (e.g., from M_n=1.41×10⁵ g mol⁻¹, Đ=1.08 to M_n=4.89×10⁵ g mol⁻¹, Đ=1.20). The LPP by NHC/B(C₆F₅)₃ is completely chemoselective, as demonstrated by the polymerization of AMA, which selectively polymerizes the conjugated vinyl group while leaving the non-conjugated vinyl group in the allyl moiety intact, thanks to its activated monomer propagation mechanism. The resulting PAMA is syndiotactic (rr=83 %), uncross-linked, and soluble in common solvents, thus suitable for further functionalization. This quantitatively chemoselective polymerization by NHC/B(C₆F₅)₃ should provide a facile, yet powerful, approach to functional acrylic polymers.     

电话用户线增容设备在电信网中的地位和入网性能要求

本文论述了电话线增容设备在电信网中的地位并对此类设备入网所必须具备的性能提出要求。     

Fast Algorithms for Approximating Distances

In this paper we present efficient approximation algorithms for the distance selection problem. Our technique is based on the well-separated pair decomposition proposed in [8]. Received May 16, 1999; revised June 5, 2001.     

量子保密术和保密通信

基于量子物理原理的量子密码术已被证明是保密通信中密钥安全分配的有效手段．本文介绍了量子密码的基本原理，探讨了实现量子密码的几种方案，并研究了各自的密钥分配机制．还讨论了量子密码通信的历史发展和指出现存在的问题以及未来的发展前景。     

非线性约束条件下一类采取曲线搜索的可行方向法

本文推广了无约束最优化方法中采用曲线搜索这一结果,从而给出了一类非线性约束条件下来用曲线搜索的可行方向法。并且在一定的条件下,我们证明了此算法类是全局收敛的. 关键词:非线性约束;;下降可行方向对;;曲线搜索;;可行方向法;;收敛性。     

度量空间上一类压缩型映射对的公共不动点定理

给出了度量空间上一类非线性压缩型映射对的公共不动点定理,进而给出了这一对映射与另一可交换映射的公共不动点定理。推广了张石生1982年所得的关于单个映射的相应结果。     

Parameter synthesis of higher kinematic pairs

We describe a parameter synthesis algorithm for planar mechanical systems comprised of higher kinematic pairs in which each part translates along a fixed axis or rotates around a fixed point. This is an important class of systems and is not addressed by prior synthesis research. Kinematic function is computed from the CAD models of the parts and is represented graphically as configuration spaces. Design flaws appear as incorrectly shaped contact curves, as incorrectly placed intersection points, and as incorrect curve sequences. The designer reshapes the faulty curves with the keyboard mouse. The synthesis algorithm computes new parameter values that realize the changes without harmful side effects, using a novel form of constrained optimization. The algorithm has been tested on industrial applications.