Single-Round DNA Aptamer Selection by Combined Use of Capillary Electrophoresis and Next Generation Sequencing: An Aptaomics Approach for Identifying Unique Functional Protein-Binding DNA Aptamers

In DNA aptamer selection, existing methods do not discriminate aptamer sequences based on their binding affinity and function and the reproducibility of the selection is often poor, even for the selection of well-known aptamers like those that bind the commonly used model protein thrombin. In the present study, a novel single-round selection method (SR-CE selection) was developed by combining capillary electrophoresis (CE) with next generation sequencing. Using SR-CE selection, a successful semi-quantitative and semi-comprehensive aptamer selection for thrombin was demonstrated with high reproducibility for the first time. Selection rules based on dissociation equilibria and kinetics were devised to obtain families of analogous sequences. Selected sequences of the same family were shown to bind thrombin with high affinity. Furthermore, data acquired from SR-CE selection was mined by creating sub-libraries that were categorized by the functionality of the aptamers (e. g., pre-organized aptamers versus structure-induced aptamers). Using this approach, a novel fluorescent molecular recognition sensor for thrombin with nanomolar detection limits was discovered. Thus, in this proof-of-concept report, we have demonstrated the potential of a “DNA Aptaomics” approach to systematically design functional aptamers as well as to obtain high affinity aptamers.     

Newton Polytopes and Relative Entropy Optimization

Foundations of Computational Mathematics - Certifying function nonnegativity is a ubiquitous problem in computational mathematics, with especially notable applications in optimization. We study the...     

Long-Range 31P-31P Spin Coupling Constants in the 31P NMR Spectra of Phosphite Triesters

Abstract

Data are presented on the magnitudes of ⁵ J _pp and ⁶ J _PP spin-spin coupling constants in the ³¹P NMR spectra of a variety of novel polyphosphite triesters.     

室温快速合成Ag基金属有机骨架材料用于电催化还原CO2

选择具有强给电子能力的1,2,4-三唑为配体,成功合成了银基金属有机骨架材料(Ag-MOF)并用于电催化还原CO₂反应(CO₂RR)。借助粉末X射线衍射、透射电子显微镜、扫描电子显微镜、计时电流法等表征手段对材料的晶体结构、形貌和电催化CO₂RR性能进行了系统的研究。与商品化的纳米Ag颗粒对比,Ag-MOF展现出更优异的电催化CO₂RR产物选择性、催化活性和稳定性,在-0.9 V (vs RHE)时,CO的法拉第效率高达96.1%。当电压为-1.1 V (vs RHE)时,电流密度可达17 mA·cm^-2,且电极可以稳定运行300 min。这说明通过选择合适的配体结构,可以改变催化位点周围的化学环境,从而高效将CO₂转化为目标产物。     

新型4,6-脱水-α-D-吡喃型半乳糖衍生物的合成

以甲基-2,3,4,6-四-O-苄基-α-D-吡喃型半乳糖为起始原料,通过对1-位和2-位进行结构修饰,6-位选择性脱除苄基后,再引入保护基Ms(或Ts)制得3,4-二-O-苄基-6-磺酰基(或对甲苯基磺酰基)-α-D-吡喃型半乳糖衍生物(2a~2f);在AcOK/DMSO体系中于80℃反应24 h,2发生分子内亲核取代反应合成了一系列新型的4,6-脱水-α-D-吡喃型半乳糖衍生物,产率78%~88%,其结构经1H NMR,13C NMR和ESI-HR-MS表征。     

ICP-AES法测定茶叶中As,Cd,Ni,Pb等元素的含量

目的对样品前处理、酸度及茶叶中共存元素干扰的影响等因素进行探讨,方法用微波消解前处理样品,ICP-AES法同时测定茶叶中铅(Pb)、砷(As)、镉(Cd)、镍(Ni)等元素含量。结果该法的回收率在84.5%～115%之间,精密度RSD均小于9%,结论该法能满足茶叶测定要求。     

In vivo Toxicity Evaluation of a Nano-drug Delivery System Using a Caenorhabditis elegansModel System

Drug carrier materials need to possess good biological safety. Presently, most biosafety evaluation studies use rodent animal models, including rats and rabbits. However, the cost of raising these animals is relatively high and the experimental period is long. Caenorhabditis elegans(C. elegans) presents an ideal toxicological evaluation model due to its simple structure, easy cultivation, short life cycle, and evolutionary conservation. In this paper, we used C. elegans to test the biological safety of our pH-responsive carrier system(FFPFF self-assembling into a nanosphere structure, FFPFF Nps), which was designed for anti-tumor drug delivery. Our results showed that exposure to high doses of FFPFF Nps did not have a significant impact on the survival rate, growth, development, movement, and reproduction of C. elegans. The preliminary evaluation of the overall biological model of C. elegans shows that FFPFF Nps has good biological safety and warrants further study.     

油茶果壳活性炭的制备及其对Cr(Ⅵ)的去除

利用磷酸活化法制备油茶果壳活性炭,并将其作为吸附剂用于去除水溶液中的Cr(Ⅵ),同时探讨了不同参数(Cr(Ⅵ)的初始浓度、吸附剂的用量、pH、温度等)对油茶果壳活性炭吸附Cr(Ⅵ)的影响。结果表明:当温度为293 K,Cr(Ⅵ)初始浓度为250 mg/L,pH为2.0时,Cr(Ⅵ)的最大吸附量可达165.0 mg/L。根据吸附动力学原理,发现其吸附过程遵循拟二级动力学模型。Cr(Ⅵ)的去除程度随Cr(Ⅵ)初始浓度的升高而增加,且其平衡数据与Freundlich模型拟合良好。