分类: 物理学 >> 核物理学 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要:DNA origami technique, a breakthrough in DNA nanotechnology, has been widely used to prepare complex DNA nanostructures with nanoscale addressability. However, the purity and yield are generally the bottleneck to application of DNA nanostructures, and current methods for purifying DNA origami nanostructures in large quantities are time-consuming and laborious. This study aims to develop a scalable, cost-effective and contamination-free method of purifying DNA origami nanostructures. We employ an effective and convenient purification approach to purify planar rectangle DNA origami structures through rate-zonal centrifugation. By subjecting DNA origami samples to high centrifugal force in a density gradient media of glycerol, well-folded nanostructures and by-products are separated successfully, which are confirmed by agarose gel electrophoresis and atomic force microscopy (AFM). This method will aid the production of pure rectangle DNA origami nanostructures in large quantity.
分类: 物理学 >> 核物理学 分类: 物理学 >> 地球物理学、天文学和天体物理学 提交时间: 2023-09-12
摘要:The neutron capture cross sections (${n, upgamma}$) of Bromine was performed with the time-of-flight (TOF) technique at the Back-n facility of the China Spallation Neutron Source (CSNS). Prompt $ upgamma$-rays originating from neutron-induced capture events were detected by four C${}_6$D${}_6$ detectors. The pulse height weighting technique (PHWT) and the double-bunch unfolding method based on the Bayesian theory were used in the data analysis. To obtain reliable measurement results, background deductions, normalization, and corrections were carefully considered. The multilevel R-matrix Bayesian code SAMMY was used to extract the resonance parameters in the resolved resonance region (RRR). The average cross sections in unresolved resonance region the was obtained from 10 to 400 keV. The experimental results were compared with the data of several evaluated libraries and previous experiments in the resolved and unresolved resonance region. The TALYS code was used to describe the average cross sections in the unresolved resonance region. Astrophysical Maxwell average cross sections (MACSs) of ${}^{79,81}$Br from $ kT $ = 5 to 100 keV was calculated over a sufficiently wide range of neutron energies. At a thermal energy of $kT=30$ keV, the MACS value for ${}^{79}$Br 638$ pm$64 mb is in good agreement with the KADoNiS recommended value. By contrast, the value of 293$ pm$29 mb for ${}^{81}$Br is substantially higher than those of the evaluated database and the KADoNiS recommended value.