Liang Fu

There have been many reports concerning the role of dietary fiber in lowering postprandial serum glucose, and the main mechanism was regarded as the viscosity of different dietary fibers in hampering diffusion of glucose and postponing absorption and digestion of carbohydrates. In this paper, two kinds of water-insoluble dietary fibers, water-insoluble dietary fiber of wheat bran and enzyme-resistant starch of maize amylose, and four kinds of water-soluble dietary fibers, water-soluble dietary fiber of wheat bran, carboxymethyl cellulose, guar gum, and xanthan gum, were used to investigate their postprandial serum glucose lowering mechanism in vitro. The results showed that these dietary fibers lowered postprandial serum glucose levels at least by three mechanisms. First, dietary fibers increase the viscosity of small intestine juice and hinder diffusion of glucose; second, they bind glucose and decrease the concentration of available glucose in the small intestine; and, third, they retard alpha-amylase action through capsuling starch and the enzyme and might directly inhibit the enzyme. All of these decreased the absorption rate of glucose and the concentration of postprandial serum glucose.

A ray of sunshine: The title reaction sequence using ethyl 2-(3,4-dihydroisoquinolin-2(1H)-yl)acetates with a series of electron-deficient alkenes and alkynes provides rapid and efficient access to pyrrolo[2,1-a]isoquinolines (see scheme; bpy=2,2′-bipyridine, EWG=electron-withdrawing group). The reaction offers a strategically new protocol for the direct and efficient construction of the core structure of naturally occurring lamellarin alkaloids.

Sonnige Aussichten: Durch die im Titel beschriebene Sequenz werden 2-(3,4-Dihydroisochinolin-2(1H)-yl)essigsäureethylester mit einer Reihe elektronenarmer Alkene und Alkine effizient in Pyrrolo[2,1-a]isochinoline umgewandelt (siehe Schema; bpy=2,2′-Bipyridin, EWG = elektronenziehende Gruppe). Die Reaktion bietet eine neue Strategie zum direkten Aufbau der Kernstruktur natürlicher Lamellarin-Alkaloide. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

The impacts of microplastics on coral reefs are gaining attention due to findings that microplastics affect coral health. This work investigated the distribution and characteristics of microplastics in the seawater, fish, and corals in 3 atolls from the Xisha Islands of South China Sea. In the seawater samples, microplastics were detected in the outer reef slopes, reef flats, and lagoons with abundances ranging from 0.2 to 11.2, 1.0 to 12.2, and 1.0 to 45.2 items L–1, respectively. Microplastic abundance was 0–12.0 items individual–1 (0–4.7 items g–1) in fish and 1.0–44.0 items individual–1(0.02–1.3 items g–1) in coral. The predominant shape and polymer of microplastics in seawater, fish, and coral were fibrous rayon and polyethylene terephthalate (PET). Microplastic sizes primarily ranged from 20–330 μm in both the seawater and fish, while there were relatively more 1–5 mm microplastics in the corals. The shape, size, color, and polymer type distribution patterns of microplastics in seawater more closely resembled those in fish gills than those in fish gastrointestinal tracts or coral samples. This study shows that microplastics are abundant in these coral reef systems and they are captured by fish or “trapped” by corals.

Classic methods for the synthesis of allenes usually introduce only one functional group into products. In this review, we highlight the recent advances and perspectives in the synthesis of allenes by transition metal‐catalyzed 1,4‐functionalization of unactivated 1,3‐enynes.