In Situ Bioorthogonal Metabolic Labeling for Fluorescence Imaging of Virus Infection In Vivo

Optical fluorescence imaging is an important strategy to explore the mechanism of virus–host interaction. However, current fluorescent tag labeling strategies often dampen viral infectivity. The present study explores an in situ fluorescent labeling strategy in order to preserve viral infectivity and precisely monitor viral infection in vivo. In contrast to pre‐labeling strategy, mice are first intranasally infected with azide‐modified H5N1 pseudotype virus (N₃‐H5N1p), followed by injection of dibenzocyclooctyl (DBCO)‐functionalized fluorescence 6 h later. The results show that DBCO dye directly conjugated to N₃‐H5N1p in lung tissues through in vivo bioorthogonal chemistry with high specificity and efficacy. More remarkably, in situ labeling rather than conventional prelabeling strategy effectively preserves viral infectivity and immunogenicity both in vitro and in vivo. Hence, in situ bioorthogonal viral labeling is a promising and reliable strategy for imaging and tracking viral infection in vivo.     

基于国产卫星数据的深圳城市化进程中土地利用/覆盖变化探讨

土地利用/覆盖变化是全球变化中的重要组成部分,城市化进程将导致大规模的土地利用/覆盖变化.文中首先分别对1999年、2006年、2010年的CBERS和HJ-1B数据进行几何校正、拼接裁剪、分类等处理,生成土地利用/覆盖分类图,然后分别计算求得深圳市1999年到2006年和2006年到2010年的土地利用/覆盖变化转移矩阵.在此基础上,研究深圳市从1999年到2010年期间土地利用/覆盖变化的空间过程.结果表明:深圳市在快速城市化进程中发生了大规模的土地利用/覆盖变化,大量的草地、耕地、未利用土地转化为城镇用地,草地和林地之间部分结构相互转化调整.同时,10年来深圳市土地利用/覆盖变化区域差异明显,伴随着宝安和龙岗两区城市化进程加快,关外土地利用/覆盖变化强度逐渐加强,而关内逐渐减弱.在深圳城市化进程中,城镇用地重心呈现出向北部扩展的趋势.     

Electrochemical growth of tin(II) oxide films: Application in photocatalytic degradation of methylene blue

We have investigated the semiconducting and photoelectrochemical properties of SnO films grown potentiostatically on tin substrate. The oxide is characterized by X-ray diffraction, scanning electron microscopy and Raman spectroscopy. The anodic process corresponds to the formation of SnO·nH₂O pre-passive layer that is removed upon increasing potential due to surface etching at the metal/oxide interface. SnO films deposited for long durations (>50 mn) are uniform and well adhered; they thicken up to ~50 nm by diffusion-controlled process and the growth follows a direct logarithmic law. The thickness is determined by coulometry and the X-ray diffraction indicates the tetragonal SnO phase (SG: P4/mmm) with a crystallite size of 32 nm. The Mott–Schottky plot is characteristic of n type conductivity with an electrons density of 5.72×10¹⁸ cm⁻³, a flat band potential of −0.09 V_SCE and a depletion width of ~10 nm. The valence band, located at 5.91 eV below, vacuum is made up of hybridized O²⁻:2p Sn²⁺:5s while the conduction band (4.45 eV) derives from Sn²⁺:5p orbital. The electrochemical impedance spectroscopy (EIS) measured in the range (10⁻²–10⁵ Hz) shows the contribution of the bulk and grain boundaries. The energy band diagram predicts the photodegradation of methylene blue on SnO films. 67% of the initial concentration (10 mg L⁻¹) disappears after 3 h of exposure to visible light (9 mW cm⁻²) with a quantum yield of 0.072.     

Compact circular-patch-based bandpass filter for ultra-wideband wireless communication systems

Ultra-wideband (UWB) is a radio technology that enables low-power-level, short-range, and wide-bandwidth communication, and it has been widely applied in personal area networks, precision geolocation, medical, surveillance, and vehicular radar systems. Since Federal Communications Commission released the unlicensed use of the UWB range (3.1–10.6 GHz), a significant attention has been paid to the development of UWB devices, particularly UWB bandpass filters. In this paper, we propose a novel UWB bandpass filter based on circular patch resonator that is grounded by via and perturbed by slits and defected ground structures. The resonator’s behaviour is analysed in detail and it is shown that its specific configuration allows a flexible control of the three lowest resonant modes, which are used to form UWB passband. To demonstrate the potential of the resonator, a UWB filter has been designed, fabricated, and measured. The filter is characterized by the insertion loss lower than 1 dB and return loss higher than 17 dB within the passband, as well as by very small group delay variation of only 0.07 ns. Also, the filter exhibits suppression higher than 19 dB up to 30 GHz, and very small overall dimensions of only 0.31λ_g × 0.31λ_g, and thus it outperforms other published UWB filters.     

Spore Dispersal of Fetid Lysurus mokusin by Feces of Mycophagous Insects

The ecological roles and biological mechanisms of zoochory in plants have long been foci in studies of co-evolutionary processes between plants and animals. However, the dispersal of fungal spores by animals has received comparatively little attention. In this study, the dispersal of spores of a selected fetid fungus, Lysurus mokusin, via feces of mycophagous insects was explored by: collecting volatiles emitted by the fungus using dynamic headspace extraction and analyzing them by GC-MS; testing the capacity of mycophagous insects to disperse its spores by counting spores in their feces; comparing the germinability of L. mokusin spores extracted from feces of nocturnal earwigs and natural gleba of the fungus; and assessing the ability of L. mokusin volatiles to attract insects in bioassays with synthetic scent mixtures. Numerous spores were detected in insects’ feces, the bioassays indicated that L. mokusin odor (similar to that of decaying substances) attracts diverse generalist mycophagous insects, and passage through the gut of Anisolabis maritima earwigs significantly enhanced the germination rate of L. mokusin spores. Therefore, nocturnal earwigs and diurnal flies probably play important roles in dispersal of L. mokusin spores, and dispersal via feces may be an important common dispersal mechanism for fungal reproductive tissue.     

Annular denuder method for sampling reactive gases and aerosols in the atmosphere

The annular denuder method (ADM), consisting of a denuder-filter pack assembly, has been developed to measure several gaseous and aerosol species without sampling artifacts. Its application to the determination of gaseous acids and ammonia in the atmosphere indicates that this aim is achieved, even though the ratio of analytes in the gas phase and particulate matter is extremely low. The procedure is particularly suitable for the measurement of trace levels (0.1 μg m⁻³) of HNO₃ and SO₂ (even in the presence of high levels of sulfate and nitrate) as well as of HNO₂ (by making correction for the positive interference of NO₂ and PAN).The ADM sampling and analysis precision for the examined gases does not exceed ±10% in the 0.1–10 μg m⁻³ range. By sampling at an air flow rate of 151 min⁻¹, the minimum detectable atmospheric concentrations is ∼0.1 μgm⁻³ for each species over a 3 h interval.     

多重荧光PCR鉴别羊肉掺假

目的建立可同时检测掺入羊肉中的猪、马、牛、鸭成分的多重荧光PCR检测体系。方法配制掺入猪、马、牛、鸭源性成分的模拟羊肉掺假样品,掺假比例17%~45%。筛选特异性强、敏感度高的猪、马、牛、鸭物种特异性基因,优化反应体系,建立了针对猪、牛、马、鸭两两配对的两重荧光PCR检测体系和其中3个任意组合的三重荧光PCR检测体系。结果模拟羊肉掺假样品两重荧光PCR检测结果显示,包括单个成分掺入比例低至7%的样品,其检测准确率为100%。而三重荧光PCR检测同时检测猪、牛、马、鸭四种肉品中的3种,其中猪肉、牛肉和马肉的掺假比例均为8%~15%;鸭牛肉掺假比例为5%~10%。三重荧光PCR检测结果显示,所有掺假样品中的各种掺假组分都被准确检出。结论本研究建立的多重荧光PCR检测体系能准确检出配制的模拟掺假羊肉制品中的猪、马、牛、鸭成分,可进一步研究以应用于市场肉制品及加工肉制品掺假的检测。     

Stable auto-tuning of hybrid adaptive fuzzy/neural controllers for nonlinear systems

In direct adaptive control, the adaptation mechanism attempts to adjust a parameterized nonlinear controller to approximate an ideal controller. In the indirect case, however, we approximate parts of the plant dynamics that are used by a feedback controller to cancel the system nonlinearities. In both cases, “approximators” such as linear mappings, polynomials, fuzzy systems, or neural networks can be used as either the parameterized nonlinear controller or identifier model. In this paper, we present an algorithm to tune the adaptation gain for a gradient-based hybrid update law used for a class of nonlinear continuous-time systems in both direct and indirect cases. In our proposed algorithm, the adaptation gain is obtained by minimizing the instantaneous control energy. Finally, we will demonstrate the performance of the algorithm via a wing rock regulation example.     

Simulation of a LHP-based thermal control system under orbital environment

In this paper, a thermal control system, using loop heat pipe as basic heat transfer elements, was designed for Alpha Magnetic Spectrometer. A system level model, which is integrated with the International Space Station model, was built, optimized and used to analyze several typical cases representing the orbital environment, to understand the operation of the LHP-based thermal control system during the mission time. The LHP system was proved to be able to maintain the Cryocooler within the required temperature range in most cases, while under some worst cold environments, the bypass valve needs to be activated.     

Development of a Liquid Chromatography Tandem Mass Spectrometric Method for Simultaneous Determination of 15 Aminoglycoside Residues in Porcine Tissues

A quantitative and confirmatory method has been developed for simultaneous determination of 15 aminoglycoside (AG) residues in porcine tissues (muscle, liver and kidney) by liquid chromatography tandem mass spectrometry (LC-MS/MS). The analytes were extracted from different matrices with aqueous trichloroacetic acid solution (5 %, w/v) followed by solid phase extraction (SPE) clean-up under optimised conditions. Due to the different pK _a values of the compounds, two consecutive SPE steps using Oasis HLB cartridges were used to purify all 15 AGs from sample extracts, with 9 AGs quantitatively retained on Oasis HLB cartridges at pH?<1 and the other 6 AGs retained at pH 8.5. The analytes were separated on a reversed-phase C18 column and eluted with water and acetonitrile containing the ion-pair reagent heptafluorobutyric acid (HFBA). The LC-MS/MS method was validated according to Decision 2002/657/EC. The optimised procedure was successfully applied to analyse 100 real porcine tissue samples (60 muscles, 20 livers and 20 kidneys) collected from local markets in southern China, demonstrating that the method is robust and useful for determination of residues of the 15 target AGs in porcine tissue samples.