Neuere Untersuchungen über die Lipide der Getreidestärken. Teil II. Die Lipide verschiedener Stärkearten und ihre Bindung an die Amylose

Recent Studies on Lipids of Cereal Starches. Part 2. Lipids of Various Types of Starch and their Bond to Amylose. By means of butanol/water (65 : 35) the lipids have been extracted from various cereal starches at 70°C. 1.0 respectively 1.3 %. lipids could be obtained from barley resp. oat starch. In every case lysolecithine was the main part (50–60 %). Apart from that, other lysophosphatides as well as free fatty acids were isolated and identified. The lipids bound to starch remain unchanged for a longer term. Apparently, the inclusion into the amylose helix acts as a protection against autoxidation. The amylose-lysolecithine-inclusion compound was prepared in pure form with a lysolecithine content of 10.2%. Processes for the determination of amylose so far proposed do not take into consideration the special bonding circumstances of lipids in cereal starches. Thus, amylose contents having been determined by these processes are too low.     

Kinetik und Mechanismus der Photolyse von Aryldiazoniumsalzen in Methanol. Ermittlung absoluter Geschwindigkeitskonstanten einiger Teilreaktionen

Kinetics and Mechanism of Aryldiazonium Salt Photolysis in Methanol. Determination of Absolute Rate Constants of Some Reaction Steps For benzene diazonium tetrafluoroborate and some p-substituted derivatives, the following values are determined:

• velocity constants for the photochemical electron transfer from pyrene and benzanthracene to aryl diazonium salts in acetonitrile solution (determination by quenching the donor fluorescence).
• velocity constants for electron transfer under the condition of pulse radiolysis in tert.-butanol-water solution;
• quantum yields and product composition (ArOMe, ArF and ArH, respectively) for the photolyses in methanol in the presence of varying concentrations of 2-methyl-2-nitroso-propane as a quencher of the thermal chain reaction.

The electron transfer reaction comes out be a diffusion controlled reaction, k_E = 2 …︁ 3 × 10¹⁰ M⁻¹ s⁻¹. For the total reaction a kinetic model is set up which affords absolute velocity constants from the experimental results for the following steps: Hydrogen transfer within the case radical pair \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {{\rm Ar} - {\rm N} = {\rm N}{\rm . CH}_{\rm 3} {\rm OH}{\rm .}} {\rm }^ \oplus $\end{document} (formation of ArH) k_H ≈ 10¹¹ s⁻¹; Maximal values for the photo-solvolyses (formation of Ar^⊕ → ArOMe and ArF, respectively), k_s ≲ 10⁻¹; Trapping of aryl radicals outside of the solvent cage by t-BuNO, k_q ≈ 2 × 10⁷ M⁻¹ s⁻¹. The results are discussed in the light of the kinetic model and some other facts.     

SARS-CoV-2 Infection Dysregulates Cilia and Basal Cell Homeostasis in the Respiratory Epithelium of Hamsters

Similar to many other respiratory viruses, SARS-CoV-2 targets the ciliated cells of the respiratory epithelium and compromises mucociliary clearance, thereby facilitating spread to the lungs and paving the way for secondary infections. A detailed understanding of mechanism involved in ciliary loss and subsequent regeneration is crucial to assess the possible long-term consequences of COVID-19. The aim of this study was to characterize the sequence of histological and ultrastructural changes observed in the ciliated epithelium during and after SARS-CoV-2 infection in the golden Syrian hamster model. We show that acute infection induces a severe, transient loss of cilia, which is, at least in part, caused by cilia internalization. Internalized cilia colocalize with membrane invaginations, facilitating virus entry into the cell. Infection also results in a progressive decline in cells expressing the regulator of ciliogenesis FOXJ1, which persists beyond virus clearance and the termination of inflammatory changes. Ciliary loss triggers the mobilization of p73⁺ and CK14⁺ basal cells, which ceases after regeneration of the cilia. Although ciliation is restored after two weeks despite the lack of FOXJ1, an increased frequency of cilia with ultrastructural alterations indicative of secondary ciliary dyskinesia is observed. In summary, the work provides new insights into SARS-CoV-2 pathogenesis and expands our understanding of virally induced damage to defense mechanisms in the conducting airways.     

Steric Crowding Makes Challenging C(sp3)-F Reductive Eliminations Feasible

A high-yielding fluorination of (triphos)Pt-R(+) has been achieved using an array of F(+) sources, with XeF(2) yielding R-F in minutes. The C-F coupling proved to be a stereoretentive process that proceeds via a concerted reductive elimination from a putative dicationic Pt(IV) center. The larger the steric congestion of the (triphos)Pt-C(sp3) (+) complexes, the more efficient the fluorination, seemingly a result of sterically accelerated C-F reductive elimination along with simultaneous deceleration of its competing processes (β-H elimination).     

基于级联卷积神经网络的疲劳检测

为了诊断热核聚变等离子体状态,研制了用于热 斑区等离子体诊断用的新型X射线光谱仪,能够同 时探测X射线光谱与聚爆靶图像信息。光谱检测功能由4块椭圆晶体分析器实现,材料分别 为α-石英(1010)、 α-石英(2023)、α-石英(1011)和Si(111),几乎能够覆盖2~20 keV能带范围内的X射线特 征光谱。光谱检测 结构为光源位于椭圆的一个焦点,其辐射光谱经过椭圆反射聚焦于椭圆另一焦点,由X射线 成像板(IP)接收。图 像检测功能由分幅相机匹配小孔阵列成像完成,理想状态能够得到20 幅不同时间的聚爆靶图像。在谱仪与 聚爆靶之间的调整台上设置厚为60μm的Be膜,以保护针孔与晶体避 免聚爆溅射碎片破坏。在中物院“神光- Ⅱ”升级装置上进行了打靶实验,获取了X射线光谱与聚爆靶图像信号。分析了光谱及图像 信息,并针对光谱 仪漏光问题改进了光谱仪结构,最后在神光-Ⅲ原型装置上进行了验证实验并获得比较理想 的图像信号,信噪比(SNR)数据达到15dB。