Modeling and Simulation of Non-Uniform Electrolytic Machining Based on Cellular Automata

Porous microstructure is a common surface morphology that is widely used in antifouling, drag reduction, adsorption, and other applications. In this paper, the lattice gas automata (LGA) method was used to simulate the non-uniform electrochemical machining of porous structure at the mesoscopic level. In a cellular space, the metal and the electrolyte were separated into orderly grids, the migration of corrosive particles was determined by an electric field, and the influences of the concentration gradient and corrosion products were considered. It was found that different pore morphologies were formed due to the competition between dissolution and diffusion. When the voltage was low, diffusion was sufficient, and no deposit was formed at the bottom of the pore. The pore grew faster along the depth and attained a cylindrical shape with a large depth-to-diameter ratio. As the voltage increased, the dissolution rates in all directions were the same; therefore, the pore became approximately spherical. When the voltage continued to increase, corrosion products were not discharged in time due to the rapid dissolution rate. Consequently, a sedimentary layer was formed at the bottom of the pore and hindered further dissolution. In turn, a disc-shaped pore with secondary pores was formed. The obtained simulation results were verified by experimental findings. This study revealed the causes of different morphologies of pores, which has certain guiding significance for non-uniform electrochemical machining.

ProXs drive the formation of membraneless organelles in plants

Membraneless organelles (MLOs) are non-membranous structures inside cells that organize cellular space and processes. The recent discovery that MLOs can be assembled via liquid-liquid phase separation (LLPS) advanced our understanding of these structures. However, the proteins that are capable of forming MLOs are largely unknown, especially in plants. In this study, we developed a method to identify proteins that we referred as ProXs (Proteins enriched by b-isoX) in Arabidopsis. Heterologous expression in yeast cells showed that most ProXs were capable of forming MLOs autonomously. We applied this method to several model and crop species including early and higher plants. This allowed us to generate an atlas of ProXs for studying plant MLOs. Analysis of ProXs from different species revealed high degree of conservation, supporting that they play important roles in cellular functions and are positively selected during evolution. Our method will be a valuable tool to characterize novel MLOs from desired cells and the data generated in present study will be instrumental for the plant research community to investigate MLO biology.

Rapid Ensemble Measurement of Protein Diffusion, Probe Blinking and Photobleaching Dynamics in the Complex Cellular Space

We present a fluorescence fluctuation image correlation analysis method that can rapidly and simultaneously measure the diffusion coefficient, photoblinking rates, and fraction of diffusing particles of fluorescent molecules in cells. Unlike other image correlation techniques, we demonstrated that our method could be applied irrespective of a non-uniformly distributed, immobile blinking fluorophore population. This allows us to measure blinking and transport dynamics in complex cell morphologies, a benefit for a range of super-resolution fluorescence imaging approaches that rely on probe emission blinking. Furthermore, we showed that our technique could be applied without directly accounting for photobleaching. We successfully employed our technique on several simulations with realistic EMCCD noise and photobleaching models, as well as on Dronpa-C12 labeled beta-actin in living NIH/3T3 and HeLa cells. We found that the diffusion coefficients measured using our method were consistent with previous literature values. We further found that photoblinking rates measured in the live HeLa cells varied as expected with changing excitation power.

Effect of prolonged sitting immobility on shear wave velocity of the lower leg muscles in healthy adults: A proof-of-concept study

Objective The purpose of this study is to investigate the physical changes of the lower leg muscles in the compartment by observing the changes in the shear wave velocity of the gastrocnemius, soleus and tibialis anterior muscles with time in the sitting position for 2 hours and after elevation of the lower leg. Materials and methods The subjects were 24 healthy adult males (average age 26.6 years). Shear wave velocity was measured by Aplio 500 in immobilized leg immediately after the start of sitting, 60 minutes and 120 minutes after the start of sitting. After 120 minutes the subjects raised the lower leg for 3 minutes, then measured again. Results In the lateral and medial gastrocnemius, there was a significant increase in the velocity at 60 (1.58 ± 0.06, 1.70 ± 0.09 m/s) and 120 minutes (1.70 ± 0.10, 1.83 ± 0.11 m/s) after the start of the test (1.52 ± 0.06, 1.66 ± 0.10 m/s), respectively (p<0.01). In the soleus and the tibialis anterior, there was a significant increase in the velocity at 120 minutes (1.89 ± 0.17, 2.30 ± 0.24 m/s) compared to after the start (1.60 ± 0.15, 2.15 ± 0.26 m/s), respectively (p<0.01). In all muscles, there was a significant decrease in the velocity after the raising compared to that of 120 minutes (p<0.01). Conclusions It has been reported that the change of shear wave velocity with time is proportional to the intramuscular pressure in the leg compartment, and it is assumed that the increase of shear wave velocity in the 2-hour seated leg is due to fluid retention in extra-cellular space of the compartment.

A facile combinatorial approach to construct a ratiometric fluorescent sensor: application for the real-time sensing of cellular pH changes

Realtime monitoring of the cellular environment, such as the intracellular pH, in a defined cellular space provides comprehensive understanding of the dynamics process in living cell. Considering the limitation of...

Method for Generation of Indoor GIS Models Based on BIM Models to Support Adjacent Analysis of Indoor Spaces

Methods for the generation of indoor geographic information system (GIS) models based on building information modelling (BIM) models can promote the analysis and application of indoor GIS, avoiding the complexity of traditional indoor space collection. The indoor adjacency relations (i.e., the attribute of IndoorGML) play a vital role in the adjacent query and analysis in indoor GIS applications (i.e., obtaining the neighbors or affected spaces of a cellular space in a building). However, current methods ignore the important feature, which considerably limits the spatial analysis ability of indoor GIS. Therefore, we developed a method for the generation of indoor GIS models based on BIM models to support adjacent analysis of indoor spaces. The method first devised an indoor GIS model (IGSM) by integrating spatial features (mainly adjacency relations) and the BIM model. Then, we proposed rapid modeling algorithms to mainly establish indoor adjacency relations based on the IGSM. Moreover, in the potential application of indoor GIS (e.g., indoor emergency response), we proposed a K-adjacent analysis algorithm to improve the application ability of the adjacent analysis of indoor GIS. Finally, experimental results suggest its validity and efficiency, which has substantial practical significance for the subsequent analysis and application of 3D GIS.

A Proposal for Modeling Indoor–Outdoor Spaces through IndoorGML, Open Location Code and OpenStreetMap

Traditionally, the standards of spatial modeling are oriented to represent the quantitative information of space. However, in recent years an increasingly common challenge is appearing: flexibly and appropriately integrating quantitative information that goes beyond the purely geometric. This problem has been aggravated due to the success of new paradigms such as the Internet of Things. This adds an additional challenge to the representation of this information due to the need to represent characteristic information of the space from different points of view in a model, such as WiFi coverage, dangerous surroundings, etc. While this problem has already been addressed in indoor spaces with the IndoorGML standard, it remains to be solved in outdoor and indoor–outdoor spaces. We propose to take the advantages proposed in IndoorGML, such as cellular space or multi-layered space model representation, to outdoor spaces in order to create indoor–outdoor models that enable the integration of heterogeneous information that represents different aspects of space. We also propose an approach that gives more flexibility in spatial representation through the integration of standards such as OpenLocationCode for the division of space. Further, we suggest a procedure to enrich the resulting model through the information available in OpenStreetMap.

Targeting with nanoparticles for the therapeutic treatment of brain diseases

Brain diseases including neurodegenerative disorders and tumours are among the most serious health problems, degrading the quality of life and causing massive economic cost. Nanoparticles that load and deliver drugs and genes have been intensively studied for the treatment of brain diseases, and have demonstrated some biological effects in various animal models. Among other efforts taken in the nanoparticle development, targeting of blood brain barrier, specific cell type or local intra-/extra-cellular space is an important strategy to enhance the therapeutic efficacy of the nanoparticle delivery systems. This review underlies the targeting issue in the nanoparticle development for the treatment of brain diseases, taking key exemplar studies carried out in various in vivo models.

ATP-driven separation of liquid phase condensates in bacteria

Liquid-liquid phase separated (LLPS) states are key to compartmentalise components in the absence of membranes, however it is unclear whether LLPS condensates are actively and specifically organized in the sub-cellular space and by which mechanisms. Here, we address this question by focusing on the ParABS DNA segregation system, composed of a centromeric-like sequence (parS), a DNA-binding protein (ParB) and a motor (ParA). We show that parS-ParB associate to form nanometer-sized, round condensates. ParB molecules diffuse rapidly within the nucleoid volume, but display confined motions when trapped inside ParB condensates. Single ParB molecules are able to rapidly diffuse between different condensates, and nucleation is strongly favoured by parS. Notably, the ParA motor is required to prevent the fusion of ParB condensates. These results describe a novel active mechanism that splits, segregates and localises non-canonical LLPS condensates in the sub-cellular space.