Electrical source of surface plasmon polaritons based on hybrid Au-GaAs QW structures

In this paper, the electrical excitation of surface plasmon polaritons (SPPs) based on a hybrid metal-semiconductor quantum well (QW) structure is investigated by finite-difference time-domain The hybrid structure could serve as a plasmonic source for integrated plasmonic circuits

FERONIA interacts with ABI2-type phosphatases to facilitate signaling cross-talk between abscisic acid and RALF peptide in Arabidopsis

[EN] Receptor-like kinase FERONIA (FER) plays a crucial role in plant response to small molecule hormones [e.g., auxin and abscisic acid (ABA)] and peptide signals [e.g., rapid alkalinization factor (RALF)]. It remains unknown how FER integrates these different signaling events in the control of cell growth and stress responses. Under stress conditions, increased levels of ABA will inhibit cell elongation in the roots. In our previous work, we have shown that FER, through activation of the guanine nucleotide exchange factor 1 (GEF1)/4/10-Rho of Plant 11 (ROP11) pathway, enhances the activity of the phosphatase ABA Insensitive 2 (ABI2), a negative regulator of ABA signaling, thereby inhibiting ABA response. In this study, we found that both RALF and ABA activated FER by increasing the phosphorylation level of FER. The FER loss-of-function mutant displayed strong hypersensitivity to both ABA and abiotic stresses such as salt and cold conditions, indicating that FER plays a key role in ABA and stress responses. We further showed that ABI2 directly interacted with and dephosphorylated FER, leading to inhibition of FER activity. Several other ABI2-like phosphatases also function in this pathway, and ABA-dependent FER activation required PYRABACTIN RESISTANCE (PYR)/PYR1-LIKE (PYL)/REGULATORY COMPONENTS OF ABA RECEPTORS (RCAR)-A-type protein phosphatase type 2C (PP2CA) modules. Furthermore, suppression of RALF1 gene expression, similar to disruption of the FER gene, rendered plants hypersensitive to ABA. These results formulated a mechanism for ABA activation of FER and for cross-talk between ABA and peptide hormone RALF in the control of plant growth and responses to stress signals.We thank Dr. Alice Cheung, Dr. Daniel Moura, Grossniklaus Ueli, Dr. Jigang Li, and Dr. Nieng Yan for providing plant, ABI1 antibody, or plasmid materials, and Dr. Legong Li for assistance in laser confocal microscopy. This work was supported by grants from National Natural Science Foundation of China (NSFC-31400232, 31571444), the State Key Laboratory of Molecular Developmental Biology (2015-MDB-KF-12), the Fundamental Research Funds for the Central Universities of China, and a grant from the National Science Foundation.Chen, J.; Yu, F.; Liu, Y.; Du, C.; Li, X.; Zhu, S.; Wang, X.... (2016). FERONIA interacts with ABI2-type phosphatases to facilitate signaling cross-talk between abscisic acid and RALF peptide in Arabidopsis. Proceedings of the National Academy of Sciences. 113(37):E5519-E5527. https://doi.org/10.1073/pnas.1608449113SE5519E55271133

Novel Optical Technologies for Nanofabrication

IX, 267 p. 232 illus., 162 illus. in color.onlin

Recent advances in metamaterial klystrons

As a kind of artificially structured media, electromagnetic metamaterials (MTMs) have exotic electromagnetic properties that are not found or difficult to achieve in natural materials. This class of metal/dielectric-structured artificial media has attracted great attention during the past two decades and made important breakthroughs. A variety of passive and active devices based on MTMs have been developed rapidly. Especially MTM klystrons, which show very remarkable advantages, including miniaturization, high gain, and high efficiency in the microwave band. MTM extended interaction klystrons creatively combine the advantages of MTMs, extended interaction technology, and klystrons. It provides a new design idea for the development of brand-new klystrons with high performance. In this review paper, we report the recent advances in MTM klystrons including MTM extended interaction oscillator and MTM extended interaction klystron amplifier. Furthermore, the prospects and challenges of MTM klystrons are discussed. Finally, the development trend is concluded

Vacuum sintered lunar regolith simulant: Pore-forming and thermal conductivity

Lunar regolith molding technologies are receiving an increasing attention in lunar exploration program. Most studies are carried out in the air on earth, ignored the effects of high vacuum (similar to 10(-12) mbar) on the lunar surface. This paper presents the results of a study aimed at assessing the effect of vacuum on the sintering of low Ti basalt type lunar simulant CLRS-1. The results show that porous sample with density of 1.19 g cm(-3) can be obtained by sintering at 1100 degrees C under vacuum, which has much lower thermal conductivity (0.265 W m(-1) K-1) than concrete and other lunar resource derived structural materials. It could potentially be applied as the thermal insulation material for the Moon base construction. The pore-forming mechanism in vacuum was investigated. It was found that evaporation of the products of solid dissolved mineral crystals led to a great deal of weight loss and inhibited the densification during sintering

Chem.-Asian J.

Live imaging of biomolecules with high specificity and sensitivity as well as minimal perturbation is essential for studying cellular processes. Here, we report the development of a bioorthogonal surface-enhanced Raman scattering (SERS) imaging approach that exploits small Raman reporters for visualizing cell-surface biomolecules. The cells were cultured and imaged by SERS microscopy on arrays of Raman-enhancing nanoparticles coated on silicon wafers or glass slides. The Raman reporters including azides, alkynes, and carbon-deuterium bonds are small in size and spectroscopically bioorthogonal (background-free). We demonstrated that various cell-surface biomolecules including proteins, glycans, and lipids were metabolically incorporated with the corresponding precursors bearing a Raman reporter and visualized by SERS microscopy. The coupling of SERS microscopy with bioorthogonal Raman reporters expands the capabilities of live-cell microscopy beyond the modalities of fluorescence and label-free imaging.Live imaging of biomolecules with high specificity and sensitivity as well as minimal perturbation is essential for studying cellular processes. Here, we report the development of a bioorthogonal surface-enhanced Raman scattering (SERS) imaging approach that exploits small Raman reporters for visualizing cell-surface biomolecules. The cells were cultured and imaged by SERS microscopy on arrays of Raman-enhancing nanoparticles coated on silicon wafers or glass slides. The Raman reporters including azides, alkynes, and carbon-deuterium bonds are small in size and spectroscopically bioorthogonal (background-free). We demonstrated that various cell-surface biomolecules including proteins, glycans, and lipids were metabolically incorporated with the corresponding precursors bearing a Raman reporter and visualized by SERS microscopy. The coupling of SERS microscopy with bioorthogonal Raman reporters expands the capabilities of live-cell microscopy beyond the modalities of fluorescence and label-free imaging

Protein-Based 3D Microstructures with Controllable Morphology and pH-Responsive Properties

The microtechnology of controlling stimuli-responsive biomaterials at micrometer scale is crucial for biomedical applications. Here, we report bovine serum albumin (BSA)-based three-dimensional (3D) microstructures with tunable surface morphology and pH-responsive properties via two-photon polymerization microfabrication technology. The laser processing parameters, including laser power, scanning speed, and layer distance, are optimized for the fabrication of well-defined 3D BSA microstructures. The tunable morphology of BSA microstructures and a wide range of pH response corresponding to the swelling ratio of 1.08–2.71 have been achieved. The swelling behavior of the microstructures can be strongly influenced by the concentration of BSA precursor, which has been illustrated by a reasonable mechanism. A panda face-shaped BSA microrelief with reversible pH-responsive properties is fabricated and exhibits unique “facial expression” variations in pH cycle. We further design a mesh sieve-shaped microstructure as a functional device for promising microparticle separation. The pore sizes of microstructures can be tuned by changing the pH values. Therefore, such protein-based microstructures with controllable morphology and pH-responsive properties have potential applications especially in biomedicine and biosensors

How to Optimize the Interface between Photosensitizers and TiO₂ Nanocrystals with Molecular Engineering to Enhance Performances of Dye-Sensitized Solar Cells?

In this work, the interfacial properties of a series of metal-free organic naphthodithienothiophene (<b>NDTT</b>)-based photosensitizers adsorbed on TiO₂ surfaces were investigated by a combination of ab initio calculations and experimental measurements. The calculations and experiments reveal that because of the efficient charge transfer from the adsorbed dyes to TiO₂ nanocrystal surface there is an upward shift for the energy levels of dyes and a downward shift for the conduction band of surface TiO₂ and that the band gaps for both of them are also reduced. Such electronic level alignments at the interface would lead to increased light absorption range by adsorbed dyes and increased driving force for charge injection but reduced open-circuit potential (<i>V</i>_oc). More interestingly, we found that molecule engineering of the donor group and introducing additional electron-withdrawing unit have little effect on the electronic level alignments at the interface (because band gaps of the dyes adsorbed on TiO₂ surfaces become approximately identical when compared with those of the dyes measured in solution) but that they can affect the steric effect and the charge separation at the interface to tune <i>V</i>_oc and the short-circuit current density (<i>J</i>_sc) effectively. All these findings suggest that optimizing the interfacial properties of dyes adsorbed on TiO₂ surfaces by synchronously modifying steric effects of dye molecules anchored on TiO₂ and charge-transfer and separation properties at the interfaces is important to construct efficient dye-sensitized solar cells