Aliphatic carboxylates are the most common class of surface ligands to stabilize colloidal nanocrystals. The widely used approach to identify the coordination modes between surface cationic sites and carboxylate ligands is based on the empirical infrared (IR) spectroscopic assignment, which is often ambiguous and thus hampers the practical control of surface structures. In this report, multiple techniques based on nuclear magnetic resonance (NMR) and IR spectra are applied to distinguish the different coordination structures in a series of zinc-blende CdSe nanocrystals with unique facet structures, including nanoplatelets dominated with {100} basal planes, hexahedrons with only three types of low-index facets (i.e., {100}, {110}, and {111}), and spheroidal dots without well-defined facets. Interpretation and assignment of NMR and IR signals were assisted by density functional theory (DFT) calculations. In addition to the identification of facet-sensitive bonding modes, the present methods also allow a nondestructive quantification of mixed ligands.

). † These authors contributed equally to this work. SUMMARYEthylene responsive factors (ERFs) are a large family of plant-specific transcription factors that are involved in the regulation of plant development and stress responses. However, little to nothing is known about their role in herbivore-induced defense. We discovered a nucleus-localized ERF gene in rice (Oryza sativa), OsERF3, that was rapidly up-regulated in response to feeding by the rice striped stem borer (SSB) Chilo suppressalis. Antisense and over-expression of OsERF3 revealed that it positively affects transcript levels of two mitogenactivated protein kinases (MAPKs) and two WRKY genes as well as concentrations of jasmonate (JA), salicylate (SA) and the activity of trypsin protease inhibitors (TrypPIs). OsERF3 was also found to mediate the resistance of rice to SSB. On the other hand, OsERF3 was slightly suppressed by the rice brown planthopper (BPH) Nilaparvata lugens (Stå l) and increased susceptibility to this piercing sucking insect, possibly by suppressing H 2 O 2 biosynthesis. We propose that OsERF3 affects early components of herbivore-induced defense responses by suppressing MAPK repressors and modulating JA, SA, ethylene and H 2 O 2 pathways as well as plant resistance. Our results also illustrate that OsERF3 acts as a central switch that gears the plant's metabolism towards an appropriate response to chewing or piercing/sucking insects.

Facet‐dependent on‐surface reactions are systematically studied on zinc‐blende CdSe nanoplatelets with atomically‐flat {001} basal facets and small yet non‐polar side facets. The on‐surface half‐reactions between the surface Se sites and Cd carboxylates in the solution are qualitatively equivalent to those on the spheroidal counterparts. Conversely, the on‐surface half‐reactions between the surface Cd sites and the activated Se precursors in solution show a strong facet‐dependence, which includes three distinguishable stages. In the first stage, the Se precursors adsorb onto the small and non‐polar side facets of the nanoplatelets. The second stage is initiated by the adsorbed Se precursors at the side‐basal plane edges and proceeds from the edges to the center of the basal planes in quasi‐zeroth‐order kinetics. In the third stage, the nanoplatelets are dismantled, which includes the creation of a hole in the middle and a build‐up of thick edges.

Augmented reality and visual reality (AR and VR) microdisplays require micro light emitting diodes (μLEDs) with an ultrasmall dimension (≤5 μm), high external quantum efficiency (EQE), and narrow spectral line width. Unfortunately, dry etching which is the most crucial step for the fabrication of μLEDs in current approaches introduces severe damages, which seem to become an insurmountable challenge for achieving ultrasmall μLEDs with high EQE. Furthermore, it is well-known that μLEDs which require InGaN layers as an emitting region naturally exhibit significantly broad spectral line width, which becomes increasingly severe toward long wavelengths such as green. In this paper, we have reported a combination of our selective overgrowth approach developed very recently and epitaxial lattice-matched distributed Bragg reflectors (DBRs) embedded in order to address all these fundamental issues. As a result, our μLEDs with a diameter of 3.6 μm and an interpitch of 2 μm exhibit an ultrahigh EQE of 9% at ∼500 nm. More importantly, the spectral line width of our μLEDs has been significantly reduced down to 25 nm, the narrowest value reported so far for III-nitride green μLEDs.

This article reports a nonpolar GaN metal−semiconductor− metal (MSM) photodetector (PD) with an ultrahigh responsivity and an ultrafast response speed in the ultraviolet spectral region, which was fabricated on nonpolar (112̅ 0) GaN stripe arrays with a major improvement in crystal quality grown on patterned (110) silicon substrates by means of using our twostep processes. Our nonpolar GaN MSM-PD exhibits a responsivity of 695.3 A/W at 1 V bias and 12628.3 A/W at 5 V bias, both under 360 nm ultraviolet illumination, which are more than 20 times higher and 4 orders of magnitude higher compared to the current state-of-the-art photodetector, respectively. The nonpolar GaN MSM-PD displays a rise time and a fall time of 66 and 43 μs, respectively, which are 3 orders of magnitude faster compared to the current state-of-the-art photodetector.

No abstract

Infochemicals are used by foraging parasitoids in the host selection process from habitat preference until host recognition. Kairomones from the herbivore host plays a vital role in the attraction of parasitoids, particularly in the micro‐habitat. Parasitoids are specifically attracted to their respective herbivore species even when different herbivores are present on the same plant. Chemicals emitted from different stages of host (eggs, larvae, pupae, adult), host by‐products (e.g., frass, exuviae, mandibular gland secretions, defense secretions etc.), or intra‐specific infochemicals (pheromones) can be main signals for the parasitoids. Parasitoids can differentiate between host and non‐host, between different hosts and host stages by perceiving specific volatile and contact kairomones from the host itself, host along with its by‐product, by‐products alone or intra‐specific infochemicals; of which frass (by‐product) and intra‐specific infochemicals are the most reported ones. Adult and larval parasitoids have been reported to be attracted to kairomones of their target stage or byproduct of their host. Pupal parasitoids have been found to utilize kairomones from the preceding host stage while egg parasitoids are known to exploit a variety of host infochemicals, for example, either from eggs themselves or other non‐target host stages, especially adults and adult‐related by‐products. The kairomonal chemicals identified so far include various groups, but mainly hydrocarbons. A high degree of host specificity and host acceptance is important for the parasitoids as any mistake may result in the loss of fitness.

No abstract