基于近似尺度不变特征转换的序列图像融合算法

在分析了尺度不变特征转换算法特点的基础上提出了一种近似尺度不变特征转换算法,该算法改变了传统尺度不变特征转换算法的框架,将尺度不变特征转换描述符看作是一种特殊的Harris算子,该算法既保留了尺度不变特征转换描述符的优点又降低了计算量.另外,为了提高特征匹配的精度,给出了一种新的特征点对提纯算法.实验结果表明,近似尺度不变特征转换算法在不影响匹配性能的前提下大大缩短了处理时间,经过提纯后的特征点对匹配性能显著提高,最终得到的全景图像过渡平稳,重叠区域没有显著的痕迹.     

Interfacially Bridging Covalent Network Yields Hyperstable and Ultralong Virus‐Based Fibers for Engineering Functional Materials

We present a strategy of interfacially bridging covalent network within tobacco mosaic virus (TMV) virus‐like particles (VLPs). We arranged T103C cysteine to laterally conjugate adjacent subunits. In the axis direction, we set A74C mutation and systematically investigated candidate from E50C to P54C as the other thiol function site, for forming longitudinal disulfide bond chains. Significantly, the T103C‐TMV‐E50C‐A74C shows the highest robustness in assembly capability and structural stability with the largest length, for TMV VLP to date. The fibers with lengths from several to a dozen of micrometers even survive under pH 13. The robust nature of this TMV VLP allows for reducer‐free synthesis of excellent electrocatalysts for application in harshly alkaline hydrogen evolution.     

Template‐Directed Synthesis of Porous and Protective Core–Shell Bionanoparticles

Metal–organic frameworks (MOFs) are promising high surface area coordination polymers with tunable pore structures and functionality; however, a lack of good size and morphological control over the as‐prepared MOFs has persisted as an issue in their application. Herein, we show how a robust protein template, tobacco mosaic virus (TMV), can be used to regulate the size and shape of as‐fabricated MOF materials. We were able to obtain discrete rod‐shaped TMV@MOF core–shell hybrids with good uniformity, and their diameters could be tuned by adjusting the synthetic conditions, which can also significantly impact the stability of the core–shell composite. More interestingly, the virus particle underneath the MOF shell can be chemically modified using a standard bioconjugation reaction, showing mass transportation within the MOF shell.     

Two new benzolactones from the leaves of Nicotiana tabacum and their anti-tobacco mosaic virus activities

Two new benzolactones, 5-methyl-6-prenyl-isobenzofuran-1(3H)-one (1), 5-hydroxymethyl-6-prenyl-isobenzofuran-1(3H)-one (2), together with four known phenolic compounds (3–6), were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1–6 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compounds 1–6 exhibited high anti-TMV activities with inhibition rates in the range of 16.9–26.2%, respectively.     

Sesquiterpenes from the leaves of Nicotiana tabacum and their anti-tobacco mosaic virus activity

In searching for more bioactive compounds, phytochemical investigations on the acetone extract of the leaves of Nicotiana tabacum resulted in the isolation of two new sesquiterpenes, nicosesquiterpene A and B(1 and 2), along with four known sesquiterpene derivatives(3–6). Structural elucidation of 1 and 2 was performed by spectral methods, such as HRMS, IR, UV, 1D and 2D NMR spectroscopy. Compounds 1 and 2are the first naturally occurring pterosin-type sesquiterpene bearing an isopropyl moiety. Compounds1–6 were also evaluated for their anti-tobacco mosaic virus(anti-TMV) activity. The results showed that compounds 1 and 2 exhibited high anti-TMV activity with inhibition rates of 36.7% and 45.6%,respectively, which is higher than that of positive control. The other compounds also showed potential activity with inhibition rates in the range of 22.7%–29.2%.     

Charge mosaic membranes prepared from laminated structures of PVA-based charged layers: 1. Preparation and transport properties of charged mosaic membranes

A charge mosaic (CM) membrane has high permselectivity for electrolytes. While there are many reports of attempts to prepare such membranes, it is difficult to make CM membranes for practical applications. We report the preparation of CM membranes from laminated structures of charged-poly(vinyl alcohol) (PVA) membranes. The membranes were prepared by alternately stacking negatively charged base membranes and positively charged base membranes and by cutting the stack of charged layers. Permeation experiments were performed in a dialysis system consisting of the membrane and mixed solutions of KCl and sucrose. Although the salt flux through the membrane was about 30 times less than that through the charge mosaic membrane Desalton^® (Tosoh Co. Ltd.), which was prepared using microphase separation, the permselectivity for salt of our membrane is more than 30 times higher than that of Desalton^®.     

Synthesis and antiviral activity of novel thioether derivatives containing 1,3,4-oxadiazole/thiadiazole and emodin moieties

A series of novel thioether derivatives containing 1,3,4-oxadiazole/thiadiazole and emodin moieties were designed and synthesized. The structures of the target compounds were confirmed by ¹H NMR, ¹³C NMR, Infrared, and elemental analysis. The results of bioactivity analysis showed that most of the target compounds exhibited moderate to good antiviral activity against tobacco mosaic virus at a concentration of 500 mg/L. Especially, among the title compounds, Y2, Y8, and Y10 possessed appreciable curative activity in vivo, with inhibition rates of 50.51, 52.08, and 54.62%, respectively, which were similar to that of Ningnanmycin (53.40%).     

球状功能性烟草花叶病毒纳米颗粒的制备及表征

烟草花叶病毒(TMV)由于其良好的生物相容性、单分散性、多价性、低成本等优点,已作为功能材料的基本构筑单元应用于光电器件、组织工程、疫苗载体,无机纳米材料制备等研究领域。然而,相比于棒状的TMV,球状TMV纳米颗粒无核酸分子,抗环境影响能力更强,比表面积更大。本文利用蛋白质的热致变性原理,对经基因和化学改性后的棒状TMV如半胱氨酸突变体(TMV-Cys)、赖氨酸突变体(TMV-EPMK)和β-环糊精(β-CD)修饰的TMV(TMV-β-CD)进行热变性处理,探究其形成球型纳米颗粒(TMV-SNP)的能力及功能性。结果显示,改性后的TMV经历热变性后可得到形貌均一的球型纳米颗粒,且其暴露在纳米颗粒表面的功能基团Cys、Lys和β-CD仍具有反应活性。     

烟草花叶病毒的特定位点改性及应用

病毒是自然界中已知结构最简单却侵染能力极强的生物,作为一种典型的一维棒状植物病毒,烟草花叶病毒(TMV)具有单分散的形貌与尺寸(18nm×300nm)、明确的空间结构、丰富的表面化学基团,且对哺乳动物不具有致病性,已广泛应用于电子器件、传感、成像、生物医用材料的研究。本文简述了对TMV进行基因工程或化学改性的多种方法及应用进展,并主要介绍了烟草花叶病毒在生物医用材料领域的潜在应用。     

Cytological modifications in maize plants infected by barley yellow dwarf virus and maize dwarf mosaic virus

Three inbred lines of maize (33-16, MO17 and B73) differing in their susceptibility to Barley yellow dwarf virus and Maize dwarf mosaic virus were studied to compare the ultrastructural modifications induced by the two viruses in leaf tissues of different age. The results demonstrate that the alterations induced by the two viruses in the different maize lines could depend on the particular line tested.