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101.
Xiaoyu Chen Pengyu He Siqi Xia Lixin Cui Prof. Dr. Guofu Zhong Prof. Dr. Limin Yang 《Chemical record (New York, N.Y.)》2023,23(7):e202200279
Over the recent decades, due to the special electronic characteristics and diverse reactivities, N-heterocyclic carbene (NHC) has received significant interest in organocatalyzed reactions. The formation of Breslow intermediates by NHC can convert into acyl anion equivalent, enolates, homoenolate, acyl azolium, and vinyl enolate etc., and the cycloaddition reactions of these species has attracted lots of attention. In this review, we focus on the summry of the development of NHC-activation of carbonyl carbon (or imine carbon) in situ, α-, β-, γ-, and beyond, and the cycloaddition reaction of these species. 相似文献
102.
Yijing Wu Wenjun Zheng Canrong Chen Linyan Yang Ping Tong Yanhui Zhong Zian Lin Zongwei Cai 《Journal of separation science》2023,46(22):2300482
Here, an imine-linked-based spherical covalent organic framework (COF) was prepared at room temperature. The as-synthesized spherical COF served as an adsorbent in dispersive solid-phase extraction (dSPE), by its virtue of great surface area (1542.68 m2/g), regular distribution of pore size (2.95 nm), and excellent stability. Therefore, a simple and high-efficiency dispersive solid phase extraction method based on a spherical COF coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established to determine aryl organophosphate esters in biological samples. This approach displayed favorable linearity in the range of 10.0–1000.0 ng/L (r > 0.9989), a high signal enhancement factor (58.8–181.8 folds) with low limits of detection (0.3–3.3 ng/L). Moreover, it could effectively eliminate complex matrix interference to accurately extract seven aryl organophosphate esters from mouse serum and tissue samples with spiked recoveries of 82.0%–117.4%. The as-synthesized spherical COF has been successfully applied in sample preparation. The dSPE-HPLC-MS/MS method based on a spherical COF has potential application to study the pollutants' metabolism in vivo. 相似文献
103.
Ying Liu Zhongrun Yuan Sa Liu Xiupeng Zhong Yanyan Wang Renjian Xie Wenjing Song Li Ren 《Macromolecular bioscience》2023,23(11):2300153
Hydrogels are extensively investigated as biomimetic extracellular matrix (ECM) scaffolds in tissue engineering. The physiological properties of ECM affect cellular behaviors, which is an inspiration for cell-based therapies. Photocurable hyaluronic acid (HA) hydrogel (AHAMA-PBA) modified with 3-aminophenylboronic acid, sodium periodate, and methacrylic anhydride simultaneously is constructed in this study. Chondrocytes are then cultured on the surface of the hydrogels to evaluate the effect of the physicochemical properties of the hydrogels on modulating cellular behaviors. Cell viability assays demonstrate that the hydrogel is non-toxic to chondrocytes. The existence of phenylboronic acid (PBA) moieties enhances the interaction of chondrocytes and hydrogel, promoting cell adhesion and aggregation through filopodia. RT-PCR indicates that the gene expression levels of type II collagen, Aggrecan, and Sox9 are significantly up-regulated in chondrocytes cultured on hydrogels. Moreover, the mechanical properties of the hydrogels have a significant effect on the cell phenotype, with soft gels (≈2 kPa) promoting chondrocytes to exhibit a hyaline phenotype. Overall, PBA-functionalized HA hydrogel with low stiffness exhibits the best effect on promoting the chondrocyte phenotype, which is a promising biomaterial for cartilage regeneration. 相似文献
104.
为提高土壤多元素同时检测的效率,采用超级微波消解-电感耦合等离子体发射光谱法测定土壤中钾、钠、钙、镁、铜、铁、锰、锌、磷、硫、硼、砷、镉、铬、铅、钴、镓、锂等18种元素含量。比较了超级微波消解、常规微波消解和电热板消解的处理效果,采用超级微波消解法对样品进行前处理,并优化了消解条件。在最优条件下,各元素的检出限在0.05~20 mg/kg,加标回收率在86.2%~107.5%,RSD在0.1%~3.0%,方法准确度及精密度可以满足多元素同时测定的需求,且该方法具有简单、快速、成本低、用酸量少、重现性好等特点。 相似文献
105.
Ziting Wang Tian Tian Leyi Chen Chuhan Zhang Xiao Zheng Ni Zhong Buling Wu Wen'an Xu 《Photochemistry and photobiology》2023,99(4):1181-1192
Increasing evidence suggests stem cells from human exfoliated deciduous teeth (SHEDs) serve as desirable sources of dentin regeneration. Photobiomodulation (PBM) has shown great potential in enhancing the proliferation and osteogenesis of human bone marrow mesenchymal stem cells (hBMMSCs). However, the specific role of PBM in odontogenic differentiation of SHEDs is little know, and we further investigated potential mechanism of PBM osteo/odontogenisis. A 980 nm diode laser with different energy densities of (0.5, 5, 10 J cm−2) in a 100-mW continuous wave was used for irradiation every 24 h. Osteo/odontogenic differentiation of SHEDs was achieved by performing alkaline phosphatase (ALP) and alizarin red staining (ARS) and osteo/odontogenic markers were also evaluated by qRT-PCR and western blotting. Additionally, western blot and immunohistochemical staining were performed to evaluate the levels of BMP/Smad and Wnt/β-catenin signaling-related proteins. We found that PBM at 5 J cm−1 increased mineral deposition and upregulated the expression of related osteo/odontogenic markers along with the elevated expression of β-catenin and phosphorylation level of Smad1/5/9. Furthermore, Wnt signaling inhibition using DKK1 and BMP signaling inhibition using noggin inhibited PBM-induced osteo/odontogenic marker expression when used individually or jointly. In conclusion, PBM induces the osteo/odontogenic differentiation of SHEDs through cross talk between BMP/Smad and Wnt/β-catenin signaling pathways. 相似文献
106.
Rui-Jia Chen Jun-Jie Wang Li Han Yu-Cheng Gu Zhi-Ping Xu Jia-Gao Cheng Xu-Sheng Shao Xiao-Yong Xu Zhong Li 《Journal of heterocyclic chemistry》2021,58(7):1429-1436
A series of diamide derivatives containing α-amino acids were designed and synthesized. These compounds were evaluated for their insecticidal activities against Plutella xylostella, Mythimna separate, Myzus persicae, and Tetranychus cinnabarinus. Most of the title compounds containing an l -phenylglycine skeleton were endowed with good activities at the concentration of 500 mg·L−1. Compounds ( R)-A6 showed a potential value for further optimization as an insecticidal lead with the LC50 value of 86.8 mg·L−1. 相似文献
107.
Li-Zhao Huang Yue Shui Wei Chen Zhong-Ming Li Hong-Tao Song Guang-Ai Sun Jia-Zhuang Xu Gan-Ji Zhong Dong Liu 《高分子科学》2021,39(3):365-376
The correlation between aggregates and bound rubber structures in silicone rubbers(S(phr)) with various silica fractions(ΦSi) has been investigated by contrast matching small-angle neutron scattering(SANS), swelling kinetics, and low-field nuclear magnetic resonance(NMR).Mixed solvents with deuterated cyclohexane fractions of 4.9% and 53.7% were chosen to match the scattering length densities of the matrix(SMP(phr)) and the filler(SMS(phr)), respectively. All the data consistently suggest that:(i) There is a critical threshold ΦSic between 10 and 30 phr;below ΦSic, the isolated aggregates are dominant, while beyond ΦSic, some rubber fraction is trapped among the agglomerate;(ii) ΦSiindependent thicknesses around 7.5 nm(NMR) and 8.6 nm(SANS) suggest that the bound rubber formation is determined by inherent properties of the components, and the power-law around 4.2 suggests an exponential changed gradient density of the bound rubber;(iii) SMS(80) presents a bicontinuous bound rubber with three characteristic lengths of 41, 100, and 234 nm. The expanded correlation length, a 20 nm smaller aggregate sizes suggest that such existent bicontinuous network in dry samples with less ΦSi is kind of impacted by swelling. With the obtained bound rubber models, the reinforcing mechanism of filled silicone rubber is elucidated. 相似文献
108.
An efficient sustainable and scalable strategy for the synthesis of porous cobalt/nitrogen co-doped carbons(Co@NCs) via pyrolysis of aniline-modified ZIFs,has been demonstrated.Aniline can coordinate and absorb on the surface of ZIF(ZIF-CoZn3-PhA),accelerate the precipitation of ZIFs,thus resulting in smaller ZIF particle size.Meanwhile,the aniline on the surface of ZIF-CoZn3-PhA promotes the formation of the protective carbon shell and smaller Co nanoparticles,and increases nitrogen content of the catalyst.Because of these prope rties of Co@NC-PhA-3,the oxidative esterification of 5-hydroxymethylfurfural can be carried out under ambient conditions.According to our experimental and computational results,a synergistic catalytic effect between CoN_x sites and Co nanoparticles has been established,in which both Co nanoparticles and CoN_x can activate O_2 while Co nanoparticles bind and oxidize HMF.Moreover,the formation and release of active oxygen species in CoN_x sites are reinfo rced by the electronic interaction between Co nanoparticles and CoN_x. 相似文献
109.
Shukun Wei Xiaoyou Hu Lingyu Du Linlin Zhao Hongjuan Xue Chaolun Liu James J. Chou Jin Zhong Yimin Tong Shuqing Wang Bo OuYang 《Molecules (Basel, Switzerland)》2021,26(5)
Hepatitis C Virus (HCV) is the key cause of chronic and severe liver diseases. The recent direct-acting antiviral agents have shown the clinical success on HCV-related diseases, but the rapid HCV mutations of the virus highlight the sustaining necessity to develop new drugs. p7, the viroporin protein from HCV, has been sought after as a potential anti-HCV drug target. Several classes of compounds, such as amantadine and rimantadine have been testified for p7 inhibition. However, the efficacies of these compounds are not high. Here, we screened some novel p7 inhibitors with amantadine scaffold for the inhibitor development. The dissociation constant (Kd) of 42 ARD-series compounds were determined by nuclear magnetic resonance (NMR) titrations. The efficacies of the two best inhibitors, ARD87 and ARD112, were further confirmed using viral production assay. The binding mode analysis and binding stability for the strongest inhibitor were deciphered by molecular dynamics (MD) simulation. These ARD-series compounds together with 49 previously published compounds were further analyzed by molecular docking. Key pharmacophores were identified among the structure-similar compounds. Our studies suggest that different functional groups are highly correlated with the efficacy for inhibiting p7 of HCV, in which hydrophobic interactions are the dominant forces for the inhibition potency. Our findings provide guiding principles for designing higher affinity inhibitors of p7 as potential anti-HCV drug candidates. 相似文献
110.
PAN Quan MA Feiyan PU Xinqing ZHAO Manyi WU Qiling ZHAO Na YANG Jun TANG Ben Zhong 《高等学校化学研究》2021,37(1):166-170
In this work,a fluorescent probe(TPEBe-I)was developed for adenosine triphosphate(ATP)detection based on the synergetic effect of aggregation-induced emission and counterion displacement.TPEBe-I gave weak emission in aqueous solution due to the heavy-atom effect of counter iodide ion.However,upon the addition of ATP,the new aggregate complex(TPEBe-ATP)was formed between the cationic unit of TPEBe-I and ATP through electrostatic interactions,which not only restricted the intramolecular motion of luminogen but also eliminated the quenching effect of iodide ion.As a result,the fluorescent light-up detection for ATP was successfully achieved.Moreover,TPEBe-I exhibited high selectivity towards ATP and showed a wide linear detection region towards the logarithm of ATP concentration(5—600μmol/L)with a detection limit of 1.0μmol/L,enabling TPEBe-I as a promising probe for ATP quantitative analysis. 相似文献