The cellular receptors for infectious bursal disease virus

Virus receptors are simplistically defined as cell surface molecules that mediate binding (attachment, adsorption) and/or trigger membrane fusion or entry through other processes. Infectious bursal diseasevirus (IBDV) entry into host cells occurs by recognition of specific cellular receptor(s) with viral envelope glycoprotein, which comprises the initial and key step of infection. Infection can be inhibited by blockage of the process. So the interest in receptors has been stimulated in large part by thepotential in the application of developing substances that show directed blocking activity. While for the purpose one should know which host cell and viral molecules are involved in the reciprocal recognition and interaction leading to the virus entry into the cell. Here, the review presents the currently available knowledge regarding the receptors or molecules that interact with IBDV

Cable-driven parallel robot assisted confocal imaging of the larynx

LaryngoTORS, a transoral laryngeal surgery robot, can manipulate instruments accurately. Confocal imaging has potentials in laryngeal cancer diagnosis but suffer from high scanning requirement. This work studies using LaryngoTORS to assist confocal imaging of larynx

Isolation and Purification of Sesquiterpene Lactones from Ixeris sonchifolia (Bunge) Hance by High-Speed Counter- Current Chromatography and Semi-Preparative High Performance Liquid Chromatography

Purpose: To isolate and purify sesquiterpene lactones from Ixeris sonchifolia (Bunge) Hance by highspeed counter-current chromatography (HSCCC).Methods: I. sonchifolia was extracted with water and then loaded on a glass column (10 ~ 1500 cm containing 3000g D101 macroporous resin) where various concentrations of aqueous ethanol (0, 10, 30, 50, and 95 %) were used to elute the column successively. The 50 % ethanol fraction was  purified by HSCCC using a solvent system comprised of ethyl acetate: n-butanol: methanol: water (4: 6: 1: 20, v/v), and semi-preparative high performance liquid chromatography (HPLC). The chemical structures of thecomponents obtained were further confirmed by high-resolution mass spectroscopy (MS) and nuclear magnetic resonance spectroscopy (NMR).Results: Three compounds, including ixerin Z1 (0.7 mg), ixerin Z (11.4 mg), and 11, 13α-dihydroixerin Z (8.2 mg), with purity of 96.2, 98.2, and 98.4 %, respectively, were obtained from 200 mg each of the 50 % ethanol fraction.Conclusion: HSCCC is a rapid and effective method for isolating and purifying sesquiterpene lactones from I. sonchifolia.Keywords: Sesquiterpene lactones, High-speed counter-current chromatography, Ixeris sonchifolia, Ixerin, 13α-Dihydroixeri

The fate of the homoctenids (Tentaculitoidea) during the Frasnian-Famennian mass extinction (Late Devonian)

The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals which are amongst the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian-Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian-Famennian boundary sections have been studied, in Poland, Germany, France, and the United States. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian “Upper Kellwasser Event”. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here

Optimizing the feeding operation of recombinant Escherichia coli during fed-batch cultivation based on Pontryagin's minimum principle

Recombinant Escherichia coli BL21 was used to produce human-like collagen in fed-batch culture. After building and analyzing the kinetic models of fed-batch cultures, the maximum specific growth rate, Yx/s and Yp/s were 0.411 h-1 , 0.428 g·g-1 and 0.0716 g/g, respectively. The square error of cell growth models, glucose consumption model and human-like collagen formation were almost all around 94%, which indicated that the kinetic model could describe the actual change well. According to the target, that is, to gain the highest productivity of human-like collagen, the feeding rate (F) was worked out on the basis of Pontryagin's minimum principle. In the verification experiments, the specific growth rate was controlled at 0.15 and 0.04 h-1 at the fed-batch and induction phase, respectively. The result showed that the concentrations of cell and human-like collagen could reach 87.6 and 6.11 g·L-1, and they were raised by 17.9 and 18.6%, respectively.Key words: Fed-batch culture, human-like collagen, maximum specific growth rate, Pontryagin's minimum principle, recombinant Escherichia coli

Wide-angled off-axis achromatic metasurfaces for visible light

Recently, an achromatic metasurface was successfully demonstrated to deflect light of multiple wavelengths in the same direction and it was further applied to the design of planar lenses without chromatic aberrations [Science, 347, 1342(2015)]. However, such metasurface can only work for normal incidence and exhibit low conversion efficiency. Here, we present an ultrawide-angle and high-efficiency metasurface without chromatic aberration for wavefront shaping in visible range. The metasurface is constructed by multiple metallic nano-groove gratings, which support enhanced diffractions for an ultrawide incident angle range from 10o to 80o due to the excitations of localized gap plasmon modes at different resonance wavelengths. Incident light at these resonance wavelengths can be efficiently diffracted into the same direction with complete suppression of the specular reflection. This approach is applied to the design of an achromatic flat lens for focusing light of different wavelengths into the same position. Our findings provide a facile way to design various achromatic flat optical elements for imaging and display applications

Active MR k-space Sampling with Reinforcement Learning

Deep learning approaches have recently shown great promise in accelerating magnetic resonance image (MRI) acquisition. The majority of existing work have focused on designing better reconstruction models given a pre-determined acquisition trajectory, ignoring the question of trajectory optimization. In this paper, we focus on learning acquisition trajectories given a fixed image reconstruction model. We formulate the problem as a sequential decision process and propose the use of reinforcement learning to solve it. Experiments on a large scale public MRI dataset of knees show that our proposed models significantly outperform the state-of-the-art in active MRI acquisition, over a large range of acceleration factors.Comment: Presented at the 23rd International Conference on Medical Image Computing and Computer Assisted Intervention, MICCAI 202

Bandwidth improvement of LiNbO₃ ultrasonic transducers by half-concaved inversion layer approach

Author name used in this publication: Dai, J. Y.2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

The mass area of jets

We introduce a new characteristic of jets called mass area. It is defined so as to measure the susceptibility of the jet's mass to contamination from soft background. The mass area is a close relative of the recently introduced catchment area of jets. We define it also in two variants: passive and active. As a preparatory step, we generalise the results for passive and active areas of two-particle jets to the case where the two constituent particles have arbitrary transverse momenta. As a main part of our study, we use the mass area to analyse a range of modern jet algorithms acting on simple one and two-particle systems. We find a whole variety of behaviours of passive and active mass areas depending on the algorithm, relative hardness of particles or their separation. We also study mass areas of jets from Monte Carlo simulations as well as give an example of how the concept of mass area can be used to correct jets for contamination from pileup. Our results show that the information provided by the mass area can be very useful in a range of jet-based analyses.Comment: 36 pages, 12 figures; v2: improved quality of two plots, added entry in acknowledgments, nicer form of formulae in appendix A; v3: added section with MC study and pileup correction, version accepted by JHE