Strain Phase Separation: Formation of Ferroelastic Domain Structures

Phase decomposition is a well-known process leading to the formation of two-phase mixtures. Here we show that a strain imposed on a ferroelastic crystal promotes the formation of mixed phases and domains, i.e., strain phase separation with local strains determined by a common tangent construction on the free energy versus strain curves. It is demonstrated that a domain structure can be understood using the concepts of domain/phase rule, lever rule, and coherent and incoherent strain phase separation, in a complete analogy to phase decomposition. The proposed strain phase separation model is validated using phase-field simulations and experimental observations of PbTiO3 and BiFeO3 thin films as examples. The proposed model provides a simple tool to guide and design domain structures of ferroelastic systems

Arabidopsis blue light receptor phototropin 1 undergoes blue light-induced activation in membrane microdomains

Phototropin (phot)-mediated signaling initiated by blue light (BL) plays a critical role in optimizing photosynthetic light capture at the plasma membrane (PM) in plants. However, the mechanisms underlying the regulation of phot activity at the PM in response to BL remain largely unclear. In this study, by single-particle tracking and step-wise photobleaching analysis we demonstrated that in the dark phot1-GFP proteins remain in an inactive state and mostly present as a monomer. The phot1-GFP diffusion rate and its dimerization increased in a dose-dependent manner in response to BL. In contrast, BL did not affect the lateral diffusion of kinase-inactive phot1 -GFP, whereas it did enhance its dimerization, suggesting that phot1 dimerization is independent of its phosphorylation. Förster resonance energy transfer-fluorescence lifetime imaging microscopy (FRET-FLIM) analysis revealed that the interaction between phot1-GFP and AtRem1.3-mCherry was enhanced along with increased time of BL treatment. However, the BL-dependent interaction was not obvious in plants co-expressing phot1 -GFP and AtRem1.3-mCherry, implicating that BL facilitated the translocation of functional phot1-GFP into AtRem1.3-labeled microdomains to activate phot-mediated signaling. Conversely, sterol depletion attenuated phot1-GFP dynamics, dimerization, and phosphorylation. Taken together, these results indicate that membrane microdomains act as an organizing platform essential for proper function of activated phot1 at the PM

Attosecond Transient Absorption Below the Excited States

In this study, the attosecond transient absorption (ATA) spectrum below the excited states of the helium atom was investigated by numerically solving the fully three-dimensional time-dependent Schrödinger equation. Under single-active electron approximation, the helium atom was illuminated by a combined field comprising of extreme ultraviolet (XUV) and delayed infrared (IR) fields. The response function demonstrates that the absorption near the central frequency (ωX) of the XUV field is periodically modulated during the overlapping between the XUV and IR pulses. Using the time-dependent perturbation, the absorption near ωX is attributed to the wavepacket excited by the XUV pulse. The wave function oscillating at the frequency of the XUV pulse was obtained. Furthermore, the chirp-dependent absorption spectrum near ωX potentially provides an all-optical method for characterizing the attosecond pulse duration. Finally, these results can extend to other systems, such as solids or liquids, indicating a potential for application in photonic devices, and they may be meaningful for quantum manipulation

Design of Visual Platform for Fisheries and Aquaculture Production Based on Geographic Information System Technologies

With the deterioration of ecological environment and the increasing demand for aquatic products, the development of fishing remains seriously threatened from various aspects, especially for production planning and control in particular place and time. Therefore, this technical paper develops a visual platform based on Geographic Information System (GIS) aim to help managers formulate sensible policy with the intention of achieving sustainable fisheries development. The key design of this system lies in the association of attribute database and GIS technologies referring to the Leftlet map. There are mainly two contributions in this article: (i) the visualizations of aquaculture production quantity are first proposed according to the geographical location and species category; (ii) system provides the superior results of statistical analysis on user interface due to the technical processing on data association and light or color intensities presentations. Furthermore, the web service is constructed and extended on the principles of the Browser/Server (B/S) architecture whose purpose is to reach efficiency of exploitation and operations

Dynamic Behavior of a Predator–Prey Model with Double Delays and Beddington–DeAngelis Functional Response

In the predator–prey system, predators can affect the prey population by direct killing and predation fear. In the present study, we consider a delayed predator–prey model with fear and Beddington–DeAngelis functional response. The model incorporates not only the fear of predator on prey with an intraspecific competition relationship, but also fear delay and pregnancy delay. Apart from the local stability analysis of the equilibrium points of the model, we find that time delay can change the stability of the system and cause Hopf bifurcation. Taking time delay as the bifurcation parameter, the critical values of delays in several cases are derived. In addition, we extend it to the random environment and study the stochastic ultimate boundedness of the stochastic process. Finally, our theoretical results are validated by numerical simulation

Attosecond Transient Absorption Below the Excited States

In this study, the attosecond transient absorption (ATA) spectrum below the excited states of the helium atom was investigated by numerically solving the fully three-dimensional time-dependent Schrödinger equation. Under single-active electron approximation, the helium atom was illuminated by a combined field comprising of extreme ultraviolet (XUV) and delayed infrared (IR) fields. The response function demonstrates that the absorption near the central frequency (ωX) of the XUV field is periodically modulated during the overlapping between the XUV and IR pulses. Using the time-dependent perturbation, the absorption near ωX is attributed to the wavepacket excited by the XUV pulse. The wave function oscillating at the frequency of the XUV pulse was obtained. Furthermore, the chirp-dependent absorption spectrum near ωX potentially provides an all-optical method for characterizing the attosecond pulse duration. Finally, these results can extend to other systems, such as solids or liquids, indicating a potential for application in photonic devices, and they may be meaningful for quantum manipulation

Exploring the Spatiotemporal Organization of Membrane Proteins in Living Plant Cells

Plasma membrane proteins have important roles in transport and signal transduction. Deciphering the spatiotemporal organization of these proteins provides crucial information for elucidating the links between the behaviors of different molecules. However, monitoring membrane proteins without disrupting their membrane environment remains difficult. Over the past decade, many studies have developed single-molecule techniques, opening avenues for probing the stoichiometry and interactions of membrane proteins in their native environment by providing nanometer-scale spatial information and nanosecond-scale temporal information. In this review, we assess recent progress in the development of labeling and imaging technology for membrane protein analysis. We focus in particular on several single-molecule techniques for quantifying the dynamics and assembly of membrane proteins. Finally, we provide examples of how these new techniques are advancing our understanding of the complex biological functions of membrane proteins

A modified GFP facilitates counting membrane protein subunits by step-wise photobleaching in Arabidopsis

Membrane proteins exert functions by forming oligomers or molecular complexes. Currently, step-wise photobleaching has been applied to count the fluorescently labelled subunits in plant cells, for which an accurate and reliable control is required to distinguish individual subunits and define the basal fluorescence. However, the common procedure using immobilized GFP molecules is obviously not applicable for analysis in living plant cells. Using the spatial intensity distribution analysis (SpIDA), we found that the A206K mutation reduced the dimerization of GFP molecules. Further ectopic expression of Myristoyl-GFP(A206K) driven by the endogenous AtCLC2 promoter allowed imaging of individual molecules at a low expression level. As a result, the percentage of dimers in the transgenic pCLC2::Myristoyl-mGFP(A206K) line was significantly reduced in comparison to that of the pCLC2::Myristoyl-GFP line, confirming its application in defining the basal fluorescence intensity of GFP. Taken together, our results demonstrated that pCLC2::Myristoyl-mGFP(A206K) can be used as a standard control for monomer GFP, facilitating the analysis of the step-wise photobleaching of membrane proteins in Arabidopsis thaliana

A modified GFP facilitates counting membrane protein subunits by step-wise photobleaching in Arabidopsis

Membrane proteins exert functions by forming oligomers or molecular complexes. Currently, step-wise photobleaching has been applied to count the fluorescently labelled subunits in plant cells, for which an accurate and reliable control is required to distinguish individual subunits and define the basal fluorescence. However, the common procedure using immobilized GFP molecules is obviously not applicable for analysis in living plant cells. Using the spatial intensity distribution analysis (SpIDA), we found that the A206K mutation reduced the dimerization of GFP molecules. Further ectopic expression of Myristoyl-GFP(A206K) driven by the endogenous AtCLC2 promoter allowed imaging of individual molecules at a low expression level. As a result, the percentage of dimers in the transgenic pCLC2::Myristoyl-mGFP(A206K) line was significantly reduced in comparison to that of the pCLC2::Myristoyl-GFP line, confirming its application in defining the basal fluorescence intensity of GFP. Taken together, our results demonstrated that pCLC2::Myristoyl-mGFP(A206K) can be used as a standard control for monomer GFP, facilitating the analysis of the step-wise photobleaching of membrane proteins in Arabidopsis thaliana