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Tetrahydro-ß-carboline skeletons are prominent and ubiquitous in an extraordinary range of indole alkaloid natural products and pharmaceutical compounds. Powerful synthetic approaches for stereoselective synthesis of tetrahydro-ß-carboline skeletons have immense impacts and have attracted enormous attention. Here, we outline a general chiral phosphoric acid catalyzed asymmetric 1,3-dipolar cycloaddition of 3,4-dihydro-ß-carboline-2-oxide type nitrone that enables access to three types of chiral tetrahydro-ß-carbolines bearing continuous multi-chiral centers and quaternary chiral centers. The method displays different endo/exo selectivity from traditional nitrone chemistry. The distinct power of this strategy has been illustrated by application to collective and enantiodivergent total syntheses of 40 tetrahydro-ß-carboline-type indole alkaloid natural products with divergent stereochemistry and varied architectures.

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An enantioselective Pd-catalyzed intramolecular dearomative reductive Heck reaction of N-(o-bromoaryl) indole-3-carboxamide is developed. By employing Pd(dba)2/SPINOL-based phosphoramidite as the chiral catalyst and HCO2Na as the hydride source, a series of enantioenriched spiro indolines bearing vicinal stereocenters were afforded in moderate to good yields with excellent enantioselectivities. The reductive Heck reaction of formal tetrasubstituted alkene bearing ß-hydrogens is therefore realized by inhibiting ß-H elimination.

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This paper presents the Plug-Load Appliance Identification Dataset (PLAID), a labelled dataset containing records of the electrical voltage and current of domestic electrical appliances obtained at a high sampling frequency (30 kHz). The dataset contains 1876 records of individually-metered appliances from 17 different appliance types (e.g., refrigerators, microwave ovens, etc.) comprising 330 different makes and models, and collected at 65 different locations in Pittsburgh, Pennsylvania (USA). Additionally, PLAID contains 1314 records of the combined operation of 13 of these appliance types (i.e., measurements obtained when multiple appliances were active simultaneously). Identifying electrical appliances based on electrical measurements is of importance in demand-side management applications for the electrical power grid including automated load control, load scheduling and non-intrusive load monitoring. This paper provides a systematic description of the measurement setup and dataset so that it can be used to develop and benchmark new methods in these and other applications, and so that extensions to it can be developed and incorporated in a consistent manner.

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Recently, millimeter-wave (MMW) 3D holography techniques employing a scanning 1D multiple input multiple output (MIMO) array have shown several superiorities for short-range applications than traditional single input single output (SISO) ones. However, current imaging algorithms for this emerging regime are not satisfied, either too slow as a back projection (BP) manner is used or of poor quality since several steps of approximations are introduced. In this paper, two fast fully-focused imaging algorithms are developed towards fixing these drawbacks. Both algorithms are based on the assumption that the receivers are evenly distributed. The first algorithm further hypothesizes that the transmitters are also evenly located, while the second algorithm needs looser restrictions that the transmitters can be arbitrarily positioned. The frequency domain expressions of the modified Kirchhoff method are also derived and used to promote the precision of the proposed algorithms. In addition, several implementation issues including resolution, sampling criteria and computational complexity are discussed. Finally, both simulation and experimental results validate the effectiveness of the proposed methods on reconstruction quality and computational efficiency.

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In this paper, a fast three-dimensional (3-D) frequency scaling algorithm (FSA) with large depth of focus is presented for near-field planar millimeter-wave (MMW) holographic imaging. Considering the cross-range range coupling term which is neglected in the conventional range migration algorithm (RMA), we propose an algorithm performing the range cell migration correction for de-chirped signals without interpolation by using a 3-D frequency scaling operation. First, to deal with the cross-range range coupling term, a 3-D frequency scaling operator is derived to eliminate the space variation of range cell migration. Then, a range migration correction factor is performed to compensate for the residual range cell migration. Finally, the imaging results are obtained by matched filtering in the cross-range direction. Compared with the conventional RMA, the proposed algorithm is comparable in accuracy but more efficient by using only chirp multiplications and fast Fourier transforms (FFTs). The algorithm has been tested with satisfying results by both simulation and experiment.

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An efficient wide-angle inverse synthetic aperture imaging method considering the spherical wavefront effects and suitable for the terahertz band is presented. Firstly, the echo signal model under spherical wave assumption is established, and the detailed wavefront curvature compensation method accelerated by 1D fast Fourier transform (FFT) is discussed. Then, to speed up the reconstruction procedure, the fast Gaussian gridding (FGG)-based nonuniform FFT (NUFFT) is employed to focus the image. Finally, proof-of-principle experiments are carried out and the results are compared with the ones obtained by the convolution back-projection (CBP) algorithm. The results demonstrate the effectiveness and the efficiency of the presented method. This imaging method can be directly used in the field of nondestructive detection and can also be used to provide a solution for the calculation of the far-field RCSs (Radar Cross Section) of targets in the terahertz regime.

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Ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP3Rs) are members of a family of tetrameric intracellular Ca(2+)-release channels (CRCs). While it is well known in mammals that RyRs and IP3Rs modulate multiple physiological processes, the roles of these two CRCs in the development and physiology of insects remain poorly understood. In this study, we cloned and functionally characterized RyR and IP3R cDNAs (named TcRyR and TcIP3R) from the red flour beetle, Tribolium castaneum. The composite TcRyR gene contains an ORF of 15,285 bp encoding a protein of 5,094 amino acid residues. The TcIP3R contains an 8,175 bp ORF encoding a protein of 2,724 amino acids. Expression analysis of TcRyR and TcIP3R revealed significant differences in mRNA expression levels among T. castaneum during different developmental stages. When the transcript levels of TcRyR were suppressed by RNA interference (RNAi), an abnormal folding of the adult hind wings was observed, while the RNAi-mediated knockdown of TcIP3R resulted in defective larval-pupal and pupal-adult metamorphosis. These results suggested that TcRyR is required for muscle excitation-contraction (E-C) coupling in T. castaneum, and that calcium release via IP3R might play an important role in regulating ecdysone synthesis and release during molting and metamorphosis in insects.

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Horizontal transfer (HT) of transposable elements has been recognized to be a major force driving genomic variation and biological innovation of eukaryotic organisms. However, the mechanisms of HT in eukaryotes remain poorly appreciated. The non-autonomous Helitron family, Lep1, has been found to be widespread in lepidopteran species, and showed little interspecific sequence similarity of acquired sequences at 3' end, which makes Lep1 a good candidate for the study of HT. In this study, we describe the Lep1-like elements in multiple non-lepidopteran species, including two aphids, Acyrthosiphon pisum and Aphis gossypii, two parasitoid wasps, Cotesia vestalis, and Copidosoma floridanum, one beetle, Anoplophora glabripennis, as well as two bracoviruses in parasitoid wasps, and one intracellular microsporidia parasite, Nosema bombycis. The patchy distribution and high sequence similarity of Lep1-like elements among distantly related lineages as well as incongruence of Lep1-like elements and host phylogeny suggest the occurrence of HT. Remarkably, the acquired sequences of both NbLep1 from N. bombycis and CfLep1 from C. floridanum showed over 90% identity with their lepidopteran host Lep1. Thus, our study provides evidence of HT facilitated by host-parasite interactions. Furthermore, in the context of these data, we discuss the putative directions and vectors of HT of Lep1 Helitrons.

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BACKGROUND: Ryanodine receptors (RyRs) are a distinct class of intracellular calcium (Ca(2+)) release channel. The recent discovery of diamide insecticides has prompted studies on insect RyRs. However, information about the structure and function of insect RyRs is still limited. In this study, we isolated and characterized a full-length RyR cDNA (named NlRyR) from the brown planthopper, Nilaparvata lugens (Stål) (Homoptera: Delphacidae), a serious rice pest throughout Asia. RESULTS: The composite NlRyR gene contains an open reading frame of 15 423 bp encoding a protein of 5140 amino acid residues, which shares high sequence identity (78-81%) with other insect homologues, except for two regions (IDR1: 4379-4732; IDR2: 1307-1529) with markedly low identity (44-48 and 38-41%, respectively). All hallmarks of the RyR proteins are conserved in the NlRyR protein, including the RyR domain as well as mannosyltransferase, IP3 R and RyR (pfam02815) (MIR) and RyR and IP3 R homology (pfam01365) (RIH) domains. Expression analysis of NlRyR revealed significant differences in mRNA expression levels among N. lugens developmental stages. Furthermore, three alternative splicing sites were identified in NlRyR, one of which forms the mutually exclusive exons A/B and is conserved in various insect species. Diagnostic PCR assays showed that the splice variant containing exon A was predominantly detected in all developmental stages. CONCLUSION: NlRyR may play an important role in the control of developmental processes of N. lugens. Alternative splicing may generate the functional diversity of NlRyR. The results provided the basis for further structural and functional characterization of NlRyR.

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Ryanodine receptors (RyRs) are the targets of novel diamide insecticides. The cotton bollworm, Helicoverpa armigera, is one of the most important cotton pests in the world. In this study, we report the full-length RyR cDNA sequence (named as HaRyR) of H. armigera. The 16,083-bp contiguous sequence encoded 5, 142 amino acid residues, which shares 80% and 78% overall identities with its homologues in Nilaparvata lugens (NlRyR) and Drosophila melanogaster (DmRyR), respectively. All hallmarks of RyR proteins are conserved in the HaRyR, including the GXRXGGGXGD motif conserved in the Ca(2+) release channels and four copies of RyR domain unique to RyR channels. The previously identified seven lepidopteran-specific RyR residues were also found in HaRyR (N(4977), N(4979), N(4990), L(5005), L(5036), N(5068) and T(5119)). An amino acid sequence alignment showed that the N-terminal region of HaRyR (residues 188-295) shared high sequence identity with NlRyR (94%) and DmRyR (92%), and moderate sequence identity (47-50%) with three rabbit RyR isoforms, while the short segment of the C-terminal transmembrane region of HaRyR (residues 4632-4676) exhibited moderate sequence identity with NlRyR (69%) and DmRyR (67%), and low sequence identity (19-28%) with three rabbit RyR isoforms. In addition, expression analysis of HaRyR revealed that the mRNA expression level in eggs was significantly lower than in third instar larvae, pupae and adults, and anatomical regulation of HaRyR expression was also observed with the highest expression level in head compared with thorax and abdomen. Our results lay a foundation for comprehensive structural and functional characterization of HaRyR and for understanding of the molecular mechanisms of toxicity selectivity of diamide insecticides among different species.

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