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Tetrasubstituted 2,3‐trans‐dihydrofuran and furan are important heterocyclic scaffolds in natural product, bioorganic and medicinal chemistry as well as in material science. The synthesis of both of these heterocycles starting from common and readily available starting materials are challenging. We found that in situ generated deoxybenzoin‐chalcone Michael adducts underwent oxidative annulation upon heating with molecular iodine in DMSO to provide selectively 2,3‐trans‐dihydrofurans at 80 °C and furans at 120 °C. [ABSTRACT FROM AUTHOR]

In the presence of a base catalyst (20 mol %) such as DBU, DABCO or Na2S ⋅ 3H2O/N‐methylpyrrolidone, phenylacetylenes were found to efficiently undergo sulfurative amination with elemental sulfur and anilines under neat conditions, leading to N‐aryl thioamides with complete atom efficiency. [ABSTRACT FROM AUTHOR]

Using first‐principles density functional theory, we investigated the electronic and optical properties of monolayer and multilayer nanosheets of molybdenum carbon fluoride (Mo2CF2), a two‐dimensional (2D) transition‐metal carbide MXene. The indirect band gap of the Mo2CF2 semiconductor can be engineered by controlling the number of layers where the band gap energy changes from 0.278 eV for the monolayer to 0.249 eV for the trilayer nanosheet. The decrease in band gap energy in the multilayer is due to interlayer coupling, which splits the bands according to the number of layers. Mo2CF2 behaves as a metal with an anomalous dispersion and high optical conductivity at incident photon energies of 0.68–2.19, 3.49–6.68 and 7.30–8.31 eV. It has a relatively low reflectivity and is absorbing over a broad range of photon energies from about 0.429 (2890), 0.387 (3204) and 0.345 eV (3594 nm) for the monolayer, bilayer and trilayer nanosheets, respectively, achieving peak absorption in the vacuum ultraviolet region at about 7.9 eV (157 nm). The optical properties of Mo2CF2 can likewise be tuned by varying the number of layers. The unique behavior of its optical properties along with the ability to control its electronic and optical properties enhances the potential of 2D Mo2CF2 for various applications in the fields of electronics and energy storage. [ABSTRACT FROM AUTHOR]

Summary: Image diagnosis is a very significant medical specialty. Thereby, the doctor will see the form and function of the structure inside the body. The recorded images will be an important basis to help doctors find the disease and treatment more effectively. However, the quality of medical images is a vital factor. Improving the quality of medical images and object contour are the major challenges, because each tiny detail of medical images can contain much information. Object contour in good medical image quality is hard work and it is more difficult in low‐quality medical image. The organs in the image are not clear, which is difficult for the doctor to distinguish the border of the organs in the image. In this paper, we proposed a method for object contour based on improving region growing in bandelet domain in low‐quality medical images. The method includes two stages: increasing the quality of medical image in bandelet domain and object contour by improving region growing combined with context border condition in medical images in the first stage. The result of the proposed method is better than the other methods. [ABSTRACT FROM AUTHOR]

By simply switching solvents, two sets of conditions for the total regio‐ and stereoselective photodimerization of (E)‐3‐(imidazo[1,2‐a]pyrimidin‐2‐yl)acrylic acid [(E)‐7a] have been found. In acetonitrile in the presence of benzophenone as photosensitizer or in cyclohexane, the head‐to‐head cis‐trans‐cis isomer 8a was the only observable cycloadduct. In DMSO, the head‐to‐head trans‐trans‐trans isomer 10a was obtained as the unique cycloadduct. The diester 9a, derived from 8a, was cyclized to the challenging, fully substituted diimidazobenzobutane system 13 present in benzosceptrins. The regio‐ and stereoselective photodimerization of (E)‐3‐(imidazo[1,2‐a]pyrimidin‐2‐yl)acrylic acid by sol switching is described. The diester was cyclized to the challenging, fully substituted diimidazobenzobutane system present in benzosceptrins. [ABSTRACT FROM AUTHOR]