Cyanogenesis—a general phenomenon in the lepidoptera?

There are two different pathways known to be used for the detoxification of hydrocyanic acid in insects, viz., rhodanese and 171g57925r1m542/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-cyano-l-ala-nine synthase. We consider the latter to be indicative for cyanogenesis, while rhodanese might, in general, play a more important role in sulfur transfer for protein synthesis. This paper reports on the distribution of 171g57925r1m542/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-cyano-l-alanine (BCA) in the Lepidoptera. First reports of cyanogenesis are presented for the following families: Papilionidae, Pieridae, Lycaenidae, Hesperiidae, Lymantriidae, Arctiidae, Notodontidae, Megalopygidae, Limacodidae, Cymatophoridae, Noctuidae, Geometridae, and Yponomeutidae. New and old records for three other families, the Nymphalidae, Zygaenidae, and Heterogynidae, are included to complete the present state of knowledge. Special emphasis has been laid on the Nymphalidae, where BCA has been detected in eight subfamilies. Taxonomic, geographic, and seasonal variation has been found in a number of cases. In all cases observed so far, the source of cyanogenesis in the Lepidoptera is most probably the cyanoglucosides linamarin and lotaustralin, although cyanogenesis based on mustard oil glucosides and cyclopentenoid glucosides might occur as well. BCA has been found in both cryptic and aposematic species, including taxa such as the Pieridae, Danainae, Ithomiinae, and Arctiidae, where the defensive biology is believed to be linked with other compounds, like mustard oil glucosides, cardenolides, or pyrrolizidine alkaloids. The ecological interaction and significance of such secondary compounds is not yet understood.     

Deposition and characterisation of TiO2 coatings on various supports for structured (photo)catalytic reactors

Different types of aqueous TiO₂–P25 suspensions were prepared and their properties, including rheological behaviour and zeta potential, were studied. Then, TiO₂ suspensions were used to elaborate TiO₂ coatings on various substrates (cordierite monolith, stainless steel plates and 171-1-Y/0?wchp=dGLzVzb-zSkWA" alt="View the MathML source" title="View the MathML source" style="vertical-align:bottom" border="0" height=15 width="10"/>-SiC foam) using a dip-coating method. The relationship between the suspension stability and the coating adhesion has been considered. The structural and morphological characterisation of TiO₂ coatings has been performed using scanning electron microscopy, X-ray diffraction and other methods. Finally, the photocatalytic properties of the materials have been determined by studying the photooxidation of aqueous ammonia.     

基于大数据图像处理的产品造型智能设计探索

目的 针对当前设计师囿于已有经验和当前的产品创新设计方法,导致设计师不能完全把握产品设计的流行趋势,易出现设计雷同和侵权等问题,提出了一种利用基于深度学习的图像处理等技术,研究基于产品图像数据库的智能造型设计方法,为设计师开发新产品提供灵感,优化产品设计流程.方法 首先利用爬虫技术从购物网站上抓取产品图像,利用图像处理算法去除重复、背景杂乱的图像.然后分析图像包含的客观特征,利用多标签学习技术对图像进行分类标注,形成一个可以实时更新、带有标签的多层次灵活分类的产品图像数据库,该数据库可以方便设计师利用标签检索.利用生成对抗网络技术进行风格迁移学习,生成与原图像类似但是有不同的新图像.最后经过有经验的设计师参与设计,得到新的方案草图.结论 基于数据驱动的造型智能设计方法,可以在一定程度上提高设计效率,缩短设计周期,为造型设计提供一种新的思维方式.     

山东玲珑金矿田东风矿区171号金矿脉地质特征及深部资源预测

通过对东风矿区171号脉金矿浅部矿床成矿条件、矿脉特征、矿体特征、围岩蚀变等的分析研究,探讨和总结了矿床成因及成矿规律,并结合矿田及国内、外类似矿床的成矿预测资料与现行勘查成果,预测了深部矿体资源。通过实际勘查发现了一大型金矿床,对我国深部盲矿勘查工作有一定的指导意义。     

The NMR properties of Yb nucleus in AYbI3 (A: K, Rb, Cs) in solid state

The powder and magic-angle spinning (MAS) experiments on ¹⁷¹Yb in AYbI₃ (A: K, Rb, Cs) are reported. The NMR parameters, such as the principal components of the chemical shielding tensor (δ₁₁, δ₂₂, δ₃₃), the spin-lattice relaxation time and the parallel and perpendicular components (T₁, T₁, T₁) are determined in solid state and the transverse relaxation time was obtained from the natural line width. The local symmetry of Yb was discussed according to the spectra.     

Possible Adverse Effects of Food Additive E171 (Titanium Dioxide) Related to Particle Specific Human Toxicity,Including the Immune System

Titanium dioxide (TiO₂) is used as a food additive (E171) and can be found in sauces, icings, and chewing gums, as well as in personal care products such as toothpaste and pharmaceutical tablets. Along with the ubiquitous presence of TiO₂ and recent insights into its potentially hazardous properties, there are concerns about its application in commercially available products. Especially the nano-sized particle fraction (<100 nm) of TiO₂ warrants a more detailed evaluation of potential adverse health effects after ingestion. A workshop organized by the Dutch Office for Risk Assessment and Research (BuRO) identified uncertainties and knowledge gaps regarding the gastrointestinal absorption of TiO₂, its distribution, the potential for accumulation, and induction of adverse health effects such as inflammation, DNA damage, and tumor promotion. This review aims to identify and evaluate recent toxicological studies on food-grade TiO₂ and nano-sized TiO₂ in ex-vivo, in-vitro, and in-vivo experiments along the gastrointestinal route, and to postulate an Adverse Outcome Pathway (AOP) following ingestion. Additionally, this review summarizes recommendations and outcomes of the expert meeting held by the BuRO in 2018, in order to contribute to the hazard identification and risk assessment process of ingested TiO₂.     

从ISO/TC171名称的变化看文献影像技术的发展

本文回顾了历史上ISO/TC 171名称的几次变化，指出技术委员会的名称是技术主流与发展趋势的反映，ISO/TC 171建议采用的新名称凸现了信息的概念，淡化了影像的概念，顺应了技术发展的需要。本文还建议全国文献影像技术标准化技术委员会的名称应保持相对稳定，同时积极推动数字影像技术和网络技术在文献影像技术应用领域的应用。     

Experimental study on diffusion combustion of high-speed hydrogen round microjets

Experimental data on the phenomenon of nozzle choking at diffusion combustion of a high-speed hydrogen microjet at its ignition close to the nozzle are presented. As is found, such a phenomenon is due to the nozzle heating by the &#171;bottleneck flame region» which is generated at the origin of microjet. This flow region persists up to transonic velocities of the microjet preventing from cooling of the nozzle and the transition to supersonic speed. In the case of hydrogen ignition far from the nozzle exit in supersonic conditions, the &#171;bottleneck flame region» is suppressed, the flame becomes detached from the nozzle which is no longer heated so that the supersonic range is attained. The subsonic combustion of hydrogen microjet is stabilized by the &#171;bottleneck flame region» while the supersonic one becomes more stable at the generation of shock cells. The results of the present study provide new details on the combustion of hydrogen microjets and could by useful for the operation of different burners.     

Evaluation of the content of TiO2 nanoparticles in the coatings of chewing gums

Titanium dioxide is a metal oxide used as a white pigment in many food categories, including confectionery. Due to differences in the mass fraction of nanoparticles contained in TiO₂, the estimated intakes of TiO₂ nanoparticles differ by a factor of 10 in the literature. To resolve this problem, a better estimation of the mass of nanoparticles present in food products is needed. In this study, we focused our efforts on chewing gum, which is one of the food products contributing most to the intake of TiO₂. The coatings of four kinds of chewing gum, where the presence of TiO₂ was confirmed by Raman spectroscopy, were extracted in aqueous phases. The extracts were analysed by transmission electron microscopy (TEM), X-ray diffraction, Fourier Transform Raman spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-AES) to establish their chemical composition, crystallinity and size distribution. The coatings of the four chewing gums differ chemically from each other, and more specifically the amount of TiO₂ varies from one coating to another. TiO₂ particles constitute the entire coating of some chewing gums, whereas for others, TiO₂ particles are embedded in an organic matrix and/or mixed with minerals like calcium carbonate, talc, or magnesium silicate. We found 1.1 ± 0.3 to 17.3 ± 0.9 mg TiO₂ particles per piece of chewing gum, with a mean diameter of 135 ± 42 nm. TiO₂ nanoparticles account for 19 ± 4% of all particles, which represents a mass fraction of 4.2 ± 0.1% on average. The intake of nanoparticles is thus highly dependent on the kind of chewing gum, with an estimated range extending from 0.04 ± 0.01 to 0.81 ± 0.04 mg of nano-TiO₂ per piece of chewing gum. These data should serve to refine the exposure scenario.     

Identification of Nanoscale Ingredients in Commercial Food Products and their Induction of Mitochondrially Mediated Cytotoxic Effects on Human Mesenchymal Stem Cells

Titanium dioxide (E171) and silicon dioxide (E551) are common additives found in food products, personal‐care products, and many other consumer products used in daily life. Recent studies have reported that these food additives (manufactured E171 and E551) contain nanosized particles of less than 100 nm. However, the particle size distribution and morphology of added TiO₂ and SiO₂ particles are not typically stated on the package label. Furthermore, there is an increasing debate regarding health and safety concerns related to the use of synthetic food additives containing nanosized ingredients in consumer products. In this study, we identified the size and morphology of TiO₂ and SiO₂ particles in commercially available food products by using transmission electron microscope (TEM). In addition, the in vitro toxicological effects of E171 and E551 on human mesenchymal stem cells (hMSCs), an adult stem cell‐based model, were assessed using the MTT assay and a flow cytometry‐based JC‐1 assay. Our TEM results confirmed the presence of nanoscale ingredients in food products, and the in vitro toxicology results indicated that the nanoscale E171 and E551 ingredients induced dose‐dependent cytotoxicity, changes in cellular morphology, and the loss of mitochondrial trans‐membrane potential in hMSCs. These preliminary results clearly demonstrated that the nanoscale E171 and E551 particles had adverse effects on hMSCs by inducing oxidative stress‐mediated cell death. Accordingly, further studies are needed to identify the specific pathway involved, with an emphasis on differential gene expression in hMSCs.