Experiment on inducing apoptosis of melanoma cells by micro-plasma jet

As a promising cancer treatment method,cold atmospheric plasma has received widespread attention in recent years.However,previous research has focused more on how to realize and expand the anti-cancer scope of plasma jet.There are also studies on the killing of small-scale cancer cells,but the effects of plasma jet on normal cells and normal cell clusters have been ignored.Therefore,we proposed a 50μm sized micro-plasma jet device,and used the device to treat melanoma cells(A-375)and human glial cells(HA1800)to evaluate their anti-cancer effects and effects on normal cells.The experimental results show that this kind of micro-plasma jet device can effectively inactivate cancer cells in a short period of time,while having little effect on normal cells.This work provides a certain experimental basis for the application offine plasma jet to clinically inactivate cancer cells.

Flow Structure and Short-Term Riverbed Evolution in Curved Flumes

River bending is the major effect responsible for bed topography and bank changes.In this study,fluid velocity(measured by a three-dimensional Doppler advanced point current meter)and bed topographical data have been collected in 40 sections of an experimental model.The whole flume was composed of an organic glass bend,upstream and downstream water tanks,two transition straight sections,a circulation pump,and a connection pipeline.Each section has been found to be characterized by a primary circulation and a small reverse circulation,with some sections even presenting three more or more circulation structures.The minimum circulation intensity has been detected in proximity to the top of the curved channel,while a region with small longitudinal velocity has been observed near the concave bank of each bend,corresponding to the flat bed formed after a short period of scouring.The maximum sediment deposition and scour depth in the presence of a uniform distribution of living flexible vegetation within 10 cm of the flume wall have been found to be smaller than those observed in the tests conducted without vegetation.

无机化学课程思政探索——以“配位化学基础”中部分内容的教学设计为例

课程思政是将思想政治教育元素融入课程教学,深化专业课程教书育人的内涵。在教学过程中,以基础理论知识为主线,融入化学发展史、化学家的主要贡献、化学学科和生产生活的紧密联系以及当代科技研究前沿等内容,构建无机化学课程思政教学体系。本文以配位化学基础中部分内容的教学设计为例,对思政案例进行介绍。

Derivation of lattice Boltzmann equation via analytical characteristic integral

A lattice Boltzmann(LB) theory, the analytical characteristic integral(ACI) LB theory, is proposed in this paper.ACI LB theory takes the Bhatnagar–Gross–Krook(BGK)-Boltzmann equation as the exact kinetic equation behind Navier–Stokes continuum and momentum equations and constructs an LB equation by rigorously integrating the BGK-Boltzmann equation along characteristics. It is a general theory, supporting most existing LB equations including the standard lattice BGK(LBGK) equation inherited from lattice-gas automata, whose theoretical foundation had been questioned. ACI LB theory also indicates that the characteristic parameter of an LB equation is collision number, depicting the particle-interaction intensity in the time span of the LB equation, instead of the traditionally assumed relaxation time, and the over-relaxation time problem is merely a manifestation of the temporal evolution of equilibrium distribution along characteristics under high collision number, irrelevant to particle kinetics. In ACI LB theory, the temporal evolution of equilibrium distribution along characteristics is the determinant of LB method accuracy and we numerically prove this.

Bucket Group Effect of the Composite Multi-bucket Structure

As a novel type of foundation in beach and shallow sea, the bucket structure is especially suitable for complex conditions such as soft clay ground and the worse types of sea environments. In this paper, the bearing capacity of a multi-bucket structure is studied by experiments with a single bucket and four-bucket foundation in a saturated sand layer. Based on the experimental data and numerical analysis results, the bearing capacity behavior and the bucket group effect are compared and analyzed. Furthermore, some influential factors, such as the soil type, the ratio of length to diameter L/D, the ratio of the bucket spacing to the bucket diameter S/D, and the bucket number are introduced and their effects on the multi-bucket structural capacity are investigated. The vertical static capacity adjustment factor is introduced to evaluate the bucket group effects of the multi-bucket foundation.

On-node lattices construction using partial Gauss–Hermite quadrature for the lattice Boltzmann method

A concise theoretical framework,the partial Gauss–Hermite quadrature(pGHQ),is established to construct on-node lattices of the lattice Boltzmann(LB)method under a Cartesian coordinate system.Compared with the existing approaches,the pGHQ scheme has the following advantages:extremely concise algorithm,unifies the constructing procedure for symmetric and asymmetric on-node lattices,and covers a full-range quadrature degree of a given discrete velocity set.We employ the pGHQ scheme to search the local optimal and asymmetric lattices for{n=3,4,5,6,7}moment degree equilibrium distribution discretization on the range[-10,10].The search reveals a surprising abundance of available lattices.Through a brief analysis,the discrete velocity set shows a significant influence on the positivity of equilibrium distributions,which is considered as one of the major impacts of the numerical stability of the LB method.Hence,the results of the p GHQ scheme lay a foundation for further investigations to improve the numerical stability of the LB method by modifying the discrete velocity set.It is also worth noting that pGHQ can be extended into the entropic LB model,even though it was proposed for the Hermite polynomial expansion LB theory.

Crystal structure of Cas1 in complex with branched DNA

Cas1 is a key component of the CRISPR adaptation complex,which captures and integrates foreign DNA into the CRISPR array,resulting in the generation of new spacers.We have determined crystal structures of Thermus thermophilus Cas1 involved in new spacer acquisition both in complex with branched DNA and in the free state.Cas1 forms an asymmetric dimer without DNA.Conversely,two asymmetrical dimers bound to two branched DNAs result in the formation of a DNA-mediated tetramer,dimer of structurally asymmetrical dimers,in which the two subunits markedly present different conformations.In the DNA binding complex,the N-terminal domain adopts different orientations with respect to the C-terminal domain in the two monomers that form the dimer.Substrate binding triggers a conformational change in the loop 164–177 segment.This loop is also involved in the 3′fork arm and 5′fork arm strand recognition in monomer A and B,respectively.This study provides important insights into the molecular mechanism of new spacer adaptation.

Effects of offshore artificial islands on beach stability of sandy shores:case study of Hongtang Bay,Hainan Province

Artificial island-type reclamation often exerts certain impacts on near-shore sandy shoreline resources and coastal ecological landscapes.The relationship between artificial islands and offshore beach evolution has attracted considerable attention in coastal protection and engineering construction.In this study,we consider Hongtang Bay in Hainan Province,China,as the research object.We adopted the Gao-Collins model to investigate the substrate transport trend in this sea area based on the analysis of the measured hydrologic and sediment data.The shore section from Nanshanjiao to Hongtangling(Taling),including the flat and straight shore sections,is dominated by the lateral transport trend of the vertical shore.The near-shore water has a strong lateral sediment transport capacity,while the outer deep-water area exhibits a sediment transport trend consistent with the tidal current movement.Using multi-year topographic data,the shoreline and seabed alterations in Hongtang Bay were analyzed,and the LITLINE beach evolution model was adopted to simulate the effects of three artificial island layouts with different island filling areas,offshore distances,and plan forms on the near-shore shoreline deformation.The results obtained indicate that the artificial island arrangement with a large offshore distance and a small area has relatively substantial advantages,such as minimizing the adverse effects of artificial island implementation on the near-shore beach.