Aryl-C-glycosides, of both synthetic and natural origin, are of great significance in medicinal chemistry owing to their unique structures and stability towards enzymatic and chemical hydrolysis as ...compared to O-glycosides. They are well-known antibiotics and potent enzyme inhibitors and possess a wide range of biological activities such as anticancer, antioxidant, antiviral, hypoglycemic effects, and so on. Currently, a number of aryl-C-glycoside drugs are on sale for the treatment of diabetes and related complications. This review summarizes the findings on aryl-C-glycoside scaffolds over the past 20 years, concerning new structures (over 200 molecules), their bioactivities—including anticancer, anti-inflammatory, antioxidant, antivirus, glycation inhibitory activities and other pharmacological effects—as well as their synthesis.
Abstract
As one of the most important photocatalysts, TiO
2
has triggered broad interest and intensive studies for decades. Observation of the interfacial reactions between water and TiO
2
at ...microscopic scale can provide key insight into the mechanisms of photocatalytic processes. Currently, experimental methodologies for characterizing photocatalytic reactions of anatase TiO
2
are mostly confined to water vapor or single molecule chemistry. Here, we investigate the photocatalytic reaction of anatase TiO
2
nanoparticles in water using liquid environmental transmission electron microscopy. A self-hydrogenated shell is observed on the TiO
2
surface before the generation of hydrogen bubbles. First-principles calculations suggest that this shell is formed through subsurface diffusion of photo-reduced water protons generated at the aqueous TiO
2
interface, which promotes photocatalytic hydrogen evolution by reducing the activation barrier for H
2
(H–H bond) formation. Experiments confirm that the self-hydrogenated shell contains reduced titanium ions, and its thickness can increase to several nanometers with increasing UV illuminance.
C–H Functionalization of Aromatic Amides Zheng, Quan; Liu, Chen‐Fu; Chen, Jie ...
Advanced synthesis & catalysis,
April 8, 2020, Letnik:
362, Številka:
7
Journal Article
Recenzirano
Since the beginning of the 21st century, significant progress has been made in transition metal‐catalyzed C–H functionalization of aromatic amides. The achievements in this field have mainly focused ...on ortho (proximal) functionalization, there have been far fewer reports on remote C–H functionalization, and para‐ and meta‐selective functionalizations remain a major challenge. Interestingly, there are few related comments in this field. In a few published cases, the scope of the report is relatively narrow, either to comment on the functionalization of a specific directing group or to summarize the functionalization of a specific reaction site. Herein, for the first time, we have comprehensively summarized the C–H functionalization of aromatic amides. This review is divided into three parts: ortho‐, para‐ and meta‐C–H functionalization of aromatic amides, and is subdivided according to the type of catalyst. The directing groups, reaction types, conditions, mechanism and applications of the corresponding reactions are discussed in detail.
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A novel lead bismuth oxybromide/graphene oxide (PbBiO2Br/GO) composite photocatalyst were prepared using a controlled and nontemplate hydrothermal technique with PbBiO2Br and GO as ...the starting material. The heterojunction photocatalysts were characterized through XRD, FE-SEM-EDS, HR-TEM, XPS, DR-UV–vis, BET, PL, EPR, and UPS. Under the optimal synthesis conditions, the photocatalytic activity of PbBiO2Br/GO composites was much higher than that of PbBiO2Br. Under 25 °C, 1 atm, and 432-nm visible light irradiation at, the optimized PbBiO2Br/GO increased the rate (at 1.913 µmol g−1 h−1) of photocatalytic conversion from carbon dioxide (CO2) to methane (CH4). This conversion rate was higher than that of the original PbBiO2Br material (0.957 µmol g−1 h−1). Therefore, PbBiO2Br/GO is superior for CH4 production and has great potential as CO2 photoreduction catalysts. In addition, such catalytic performance (when using 0.05 wt%-GO/PbBiO2Br composite as a photocatalyst) indicates that the optimal reaction rate constants of crystal violet (CV) and 2-hydroxybenzoic acid (2-HBA) are 0.1278 and 0.0093 h−1, respectively, which are 1.82 and 1.24 times the reaction rate constant of PbBiO2Br as a photocatalyst, respectively. Our findings are useful for PbBiO2Br/GO synthesis and in its future environmental applications, particularly in solar fuel manufacture.
Circulating fetal nucleated cells (CFNCs) in maternal blood offer an ideal source of fetal genomic DNA for noninvasive prenatal diagnostics (NIPD). We developed a class of nanoVelcro microchips to ...effectively enrich a subcategory of CFNCs, i.e., circulating trophoblasts (cTBs) from maternal blood, which can then be isolated with single-cell resolution by a laser capture microdissection (LCM) technique for downstream genetic testing. We first established a nanoimprinting fabrication process to prepare the LCM-compatible nanoVelcro substrates. Using an optimized cTB-capture condition and an immunocytochemistry protocol, we were able to identify and isolate single cTBs (Hoechst+/CK7+/HLA-G+/CD45–, 20 μm > sizes > 12 μm) on the imprinted nanoVelcro microchips. Three cTBs were polled to ensure reproducible whole genome amplification on the cTB-derived DNA, paving the way for cTB-based array comparative genomic hybridization (aCGH) and short tandem repeats analysis. Using maternal blood samples collected from expectant mothers carrying a single fetus, the cTB-derived aCGH data were able to detect fetal genders and chromosomal aberrations, which had been confirmed by standard clinical practice. Our results support the use of nanoVelcro microchips for cTB-based noninvasive prenatal genetic testing, which holds potential for further development toward future NIPD solution.
Optical edge detection is a useful method for characterizing boundaries, which is also in the forefront of image processing for object detection. As the field of metamaterials and metasurface is ...growing fast in an effort to miniaturize optical devices at unprecedented scales, experimental realization of optical edge detection with metamaterials remains a challenge and lags behind theoretical proposals. Here, we propose a mechanism of edge detection based on a Pancharatnam–Berry-phase metasurface. We experimentally demonstrated broadband edge detection using designed dielectric metasurfaces with high optical efficiency. The metasurfaces were fabricated by scanning a focused laser beam inside glass substrate and can be easily integrated with traditional optical components. The proposed edge-detection mechanism may find important applications in image processing, high-contrast microscopy, and realtime object detection on compact optical platforms such as mobile phones and smart cameras.
The high mortality rate of glioblastoma multiforme (GBM), a lethal primary brain tumor, is attributable to postsurgical recurrence. STAT3, an oncogenic protein, is a signal transducer and ...transcription activator encourages cancer cell migration and proliferation, which results in resistance to therapy. STAT3 inhibition reduces cancer metastasis and improves patient prognosis. Bt354, a small molecule STAT inhibitor, exhibits significant cytotoxic and anti‐proliferative activities against certain cancer types. Here, we demonstrated that exposure of GBM cells (U87 MG) to Bt354 had a significant, concentration‐dependent growth suppression. Bt354 also induced apoptosis and downregulated the expression of the epithelial‐mesenchymal transition genes. Therefore, this study suggests the potential of Bt354 for treating GBM owing to its ability to induce cytotoxicity.
Electrochemical nitrate reduction to ammonia (eNO3RR) is a green and appealing method for ammonia synthesis, but is hindered by the multistep chemical reaction and competitive hydrogen generation. ...Herein, the synthesis of 2D SnS nanosheets with tailored interlayer spacing is reported, including both expansion and compression, through the active diatomic Pt‐Ce pairs. Taking together the experimental results, in situ Raman spectra, and DFT calculations, it is found that the compressed interlayer spacing can tune the electron density of localized p‐orbital in Sn into its delocalized states, thus enhancing the chemical affinity towards NO3− and NO2− but inhibiting hydrogen generation simultaneously. This phenomenon significantly facilitates the rate‐determining step (*NO3→*NO2) in eNO3RR, and realizes an excellent Faradaic efficiency (94.12%) and yield rate (0.3056 mmol cm−2 h−1) for NH3 at −0.5 V versus RHE. This work provides a powerful strategy for tailoring flexible interlayer spacing of 2D materials and opens a new avenue for constructing high‐performance catalysts for ammonia synthesis.
An interlayer spacing engineering of 2D SnS nanosheets is reported that involves adopting active diatomic Pt‐Ce, that tunes the electron density of localized p‐orbitals in Sn into its delocalized states, thus significantly improving NO3−‐to‐NH3 conversion for both activity and selectivity.
Optical image processing and computing systems provide supreme information processing rates by utilizing parallel optical architectures. Existing optical analog processing techniques require multiple ...devices for projecting images and executing computations. In addition, those devices are typically limited to linear operations due to the time‐invariant optical responses of the building materials. In this work, a single metalens with an illumination intensity dependent coherent transfer function (CTF) is proposed and experimentally demonstrated, which performs varying computed imaging without requiring any additional optical components. The metalens consisting of nanoantenna structures with a static geometric phase and a nonlinear metallic quantum well layer offering an intensity‐dependent dynamic phase results in a continuously tunable CTF. The approach allows for a weighted summation of two designed functions based on the metalens design, which potentially enables all optical computations of complex functions. The nonlinear metalens may lead to important applications in optical neural networks and parallel analog computing.
In this work, a single metalens with an illumination intensity dependent coherent transfer function (CTF) is demonstrated, which performs varying computed imaging without requiring any additional optical components. The metalens consists of nanoantenna structures providing a static geometric phase and an extreme nonlinear metallic quantum well layer offering intensity‐dependent dynamic phase, resulting in a continuously tunable CTF.
The outbreak of 2019 novel coronavirus (2019-nCoV) pneumonia was reported in Wuhan, Hubei Province, China in December 2019 and has spread internationally. This article discusses how radiology ...departments can most effectively respond to this public health emergency.
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