The field in dearomatization of aromatic compounds for the construction of spirocycle compounds has been developed rapidly over the last two decades and it provides alternative synthetic method ...without using extra stoichiometric amounts of chemical oxidants or reductants. In addition, the radical cascade reactions of alkenes or alkynes that produce multiple chemical bonds in one‐step are significant in the direct and efficient building of complex molecules. By combining these two concepts, dearomatization and radical cascade reactions of alkenes or alkynes opens a new and powerful avenue in accessing spirocycle molecules. These cascade reactions have been well explored in the past decade. As a result, we summarize recent eventful advances in this rapidly growing area as a review, in which the typical examples are listed and mechanism are also discussed.
The asymmetric catalytic addition of linear Grignard reagents to ketones has been a long‐standing challenge in organic synthesis. Herein, a novel family of PNP ligands (W‐Phos) was designed and ...applied in copper‐catalyzed asymmetric addition of linear Grignard reagents to aryl alkyl ketones, allowing facile access to versatile chiral tertiary alcohols in good to high yields with excellent enantioselectivities (up to 94 % yield, 96 % ee). The process can also be used to synthesize chiral allylic tertiary alcohols from more challenging α,β‐unsaturated ketones. Notably, the potential utility of this method is demonstrated in the gram‐scale synthesis and modification of various densely functionalized medicinally relevant molecules.
A novel family of PNP ligands (W‐Phos) was designed and applied in the copper‐catalyzed asymmetric addition of linear Grignard reagents to ketones, allowing ready access to versatile chiral tertiary alcohols in high yields and with excellent enantioselectivities.
Considering first-order corrections to entropy and temperature of Reissner–Nordström–anti-de Sitter (RN–AdS) and Kerr–Newman–anti-de Sitter (KN–AdS) black holes, effects from the corrected entropy ...and temperature on thermodynamic potentials like internal energy, enthalpy, Helmholtz energy and Gibbs free energy are analyzed. It is shown that when the black hole is large, the effects on the thermodynamic potentials are negligible. However, when the black hole is small, the thermodynamic potential of these two black holes receive observable impacts from the corrections of the entropy and temperature. We also find that these two kinds of black holes behave differently on thermodynamic potentials, since the existence of the angular momentum for KN–AdS black holes. Besides, critical behaviours in phase transitions of these AdS black hole, specific heat and scalar curvature of equilibrium state space geometry are obtained. In both of the two cases, critical points are shown to be shifted. Our work extends the former researches on corrected thermodynamics and geometrothermodynamics for AdS black holes, as corrected temperature due to Hawking radiation is considered.
Pancreatic cancer (PC) is a great health burden to patients owing to its poor overall survival rate. Long noncoding RNAs (lncRNAs) interact with microRNAs (miRs) to participate in tumorigenesis. ...Therefore, we aim to uncover the role and related mechanism of LINC00473 in PC through the modulation of miR‐195‐5p and programmed death‐ligand 1 (PD‐L1). Increased LINC00473 and PD‐L1 but declined miR‐195‐5p were determined in PC tissues and cell lines, and it was found that LINC00473 mainly situated in the cytoplasm. Also, miR‐195‐5p was verified to bind with both LINC00473 and PD‐L1. Next, with the aim to examine the ability of LINC00473, miR‐195‐5p, and PD‐L1 on the PC progression, the expression of LINC00473, miR‐195‐5p and PD‐L1 were altered with mimics, inhibitors, overexpression vectors or siRNAs in PC cells and cocultured CD8+ T cells. It was demonstrated that LINC00473 sponged miR‐195‐5p to upregulate PD‐L1 expression. More important, the obtained results revealed that LINC00473 silencing or miR‐195‐5p upregulation elevated the expression of Bcl‐2 associated X protein (Bax), interferon (IFN)‐γ, and interleukin (IL)‐4 but reduced the expression of B‐cell lymphoma‐2 (Bcl‐2), matrix metalloproteinase (MMP)‐2, MMP‐9, and IL‐10, thus inducing the enhancement of the apoptosis as along with the inhibition of proliferation, invasion, and migration of the PC cells. LINC00473 silencing or miR‐195‐5p elevation activated the CD8+ T cells. Taken together, LINC00473 silencing blocked the PC progression through enhancing miR‐195‐5p‐targeted downregulation of PD‐L1. This finding offers new therapeutic options for treating this devastating disease.
Taken together, LINC00473 silencing blocked the pancreatic cancer progression through enhancing miR‐195‐5p‐targeted downregulation of PD‐L1. This finding offers new therapeutic options for treating this devastating disease.
Cyclodextrins (CDs), which are a class of cyclic oligosaccharides extracted from the enzymatic degradation of starch, are often utilized in molecular recognition and assembly constructs, primarily ...via host–guest interactions in water. In this review, recent progress in CD‐based supramolecular nanoassemblies that are sensitive to chemical, biological, and physical stimuli is updated and reviewed, and intriguing examples of the biological functions of these nanoassemblies are presented, including pH‐ and redox‐responsive drug and gene delivery, enzyme‐activated specific cargo release, photoswitchable morphological interconversion, microtubular aggregation, and cell–cell communication, as well as a geomagnetism‐controlled nanosystem for the suppression of tumor invasion and metastasis. Moreover, future perspectives and challenges in the fabrication of intelligent CD‐based biofunctional materials are also discussed at the end of this review, which is expected to promote the translational development of these nanomaterials in the biomedical field.
Recent progress in cyclodextrin‐based multistimuli‐responsive supramolecular assemblies is systematically reviewed, their biological functions are presented by selecting some representative examples, and future perspectives and challenges in this promising field are discussed.
NH4+ ions as charge carriers show potential for aqueous rechargeable batteries. Studied here for the first time is the NH4+‐storage chemistry using electrodeposited manganese oxide (MnOx). MnOx ...experiences morphology and phase transformations during charge/discharge in dilute ammonium acetate (NH4Ac) electrolyte. The NH4Ac concentration plays an important role in NH4+ storage for MnOx. The transformed MnOx with a layered structure delivers a high specific capacity (176 mAh g−1) at a current density of 0.5 A g−1, and exhibits good cycling stability over 10 000 cycles in 0.5 M NH4Ac, outperforming the state‐of‐the‐art NH4+ hosting materials. Experimental results suggest a solid‐solution behavior associated with NH4+ migration in layered MnOx. Spectroscopy studies and theoretical calculations show that the reversible NH4+ insertion/deinsertion is accompanied by hydrogen‐bond formation/breaking between NH4+ and the MnOx layers. These findings provide a new prototype (i.e., layered MnOx) for NH4+‐based energy storage and contributes to the fundamental understanding of the NH4+‐storage mechanism for metal oxides.
NH4+ storage using electrodeposited manganese oxides (MnOx) is studied for the first time. MnOx exhibits structural transformation during charge/discharge in dilute ammonium acetate (NH4Ac) electrolyte. Experimental and theoretical results suggest that the reversible NH4+ insertion/deinsertion in layered MnOx is associated with hydrogen‐bond formation/breaking between NH4+ and the MnOx layers.
The introduction of chirality into organic–inorganic hybrid perovskites (OIHPs) is expected to achieve excellent photoelectric and nonlinear materials related to circular dichroism. Owing to the ...existence of asymmetric center and intrinsic chirality in the chiral OIHPs, the different efficiencies of second harmonic generation (SHG) signal occurs when the circularly polarized light (CPL) with different phases passes through the chiral crystal, which is defined as second harmonic generation circular dichroism (SHG‐CD). Here, the SHG‐CD effect is developed in bulk single crystals of chiral one‐dimensional (1D) (R/S)‐3‐aminopiperidinePbI4. It is the first time that CPL is distinguished using chirality‐dependent SHG‐CD effect in OIHPs bulk single crystals. Such SHG‐CD technology extends the detection range to near infrared region (NIR). In this way, the anisotropy factor (gSHG‐CD) through SHG‐CD signal is as high as 0.21.
Bulk organic–inorganic hybrid perovskite single crystals are used to effectively distinguish the circularly polarized light in the near infrared region by chirality‐dependent second harmonic generation circular dichroism (SHG‐CD) effect with a high anisotropy factor (gSHG‐CD=0.21).
The bilateral filter is a nonlinear filter that does spatial averaging without smoothing edges; it has shown to be an effective image denoising technique. An important issue with the application of ...the bilateral filter is the selection of the filter parameters, which affect the results significantly. There are two main contributions of this paper. The first contribution is an empirical study of the optimal bilateral filter parameter selection in image denoising applications. The second contribution is an extension of the bilateral filter: multiresolution bilateral filter, where bilateral filtering is applied to the approximation (low-frequency) subbands of a signal decomposed using a wavelet filter bank. The multiresolution bilateral filter is combined with wavelet thresholding to form a new image denoising framework, which turns out to be very effective in eliminating noise in real noisy images. Experimental results with both simulated and real data are provided.
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•Fluorine-free superhydrophobic silica nanotube coating was template-directed from MWCNTs.•The resulted coating shows very high transparency with self-cleaning property.•The ...transparent superhydrophobic coating can be used for protection of outdoor optical devices.
Transparent coatings with self-cleaning properties are required for protection of outdoor optical devices. Highly transparent, fluorine-free superhydrophobic coatings of silica nanotubes (SNT) on glass substrates are fabricated by using poly(dimethylsiloxane) (PDMS) as the silica source and multi-walled carbon nanotubes (MWCNTs) as the sacrificial template, following by hydrophobization through chemical vapor deposition (CVD) of cured PDMS. The influence of surface topography from SNT on the transparency and superhydrophobicity of the coatings is investigated. High transparency and excellent superhydrophobicity of the surface can be achieved by changing the concentration of PDMS (CPDMS) for SNT coatings as well as the amount of the cured PDMS (APDMS) for hydrophobization. The optimum coating has an average transmittance higher than 83% in the visible-light range (400–780nm), a water contact angle (CA) of 165° and a slide angle (SA) lower than 3°. When applied as protective cover, the glass substrate with superhydrophobic coating has little effect on the power generation efficiency of solar cells and has outstanding self-cleaning properties.
In the present paper, we investigate the dark energy equation of state using the Gaussian processes analysis method, without confining a particular parametrization. The reconstruction is carried out ...by adopting the background data including supernova and Hubble parameter, and perturbation data from the growth rate. It suggests that the background and perturbation data both present a hint of dynamical dark energy. However, the perturbation data have a more promising potential to distinguish non-evolution dark energy including the cosmological constant model. We also test the influence of some parameters on the reconstruction. We find that the matter density parameter
Ω
m
0
has a slight effect on the background data reconstruction, but has a notable influence on the perturbation data reconstruction. While the Hubble constant presents a significant influence on the reconstruction from background data.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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