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排序方式: 共有268条查询结果,搜索用时 390 毫秒
221.
Alessandro Fracassi Jianbo Cao Naoko Yoshizawa-Sugata va Tth Corey Archer Olivier Grninger Emanuela Ricciotti Soon Yew Tang Stephan Handschin Jean-Pascal Bourgeois Ankita Ray Korinne Liosi Sean Oriana Wendelin Stark Hisao Masai Rong Zhou Yoko Yamakoshi 《Chemical science》2020,11(44):11998
Low-density lipoprotein (LDL)-mimetic lipid nanoparticles (LNPs), decorated with MRI contrast agents and fluorescent dyes, were prepared by the covalent attachment of apolipoprotein-mimetic peptide (P), Gd(iii)-chelate (Gd), and sulforhodamine B (R) moieties on the LNP surface. The functionalized LNPs were prepared using the amide-forming potassium acyltrifluoroborate (KAT) ligation reaction. The KAT groups on the surface of LNPs were allowed to react with the corresponding hydroxylamine (HA) derivatives of P and Gd to provide bi-functionalized LNPs (PGd-LNP). The reaction proceeded with excellent yields, as observed by ICP-MS (for B and Gd amounts) and MALDI-TOF-MS data, and did not alter the morphology of the LNPs (mean diameter: ca. 50 nm), as shown by DLS and cryoTEM analyses. With the help of the efficient KAT ligation, a high payload of Gd(iii)-chelate on the PGd-LNP surface (ca. 2800 Gd atoms per LNP) was successfully achieved and provided a high r1 relaxivity (r1 = 22.0 s−1 mM−1 at 1.4 T/60 MHz and 25 °C; r1 = 8.2 s−1 mM−1 at 9.4 T/400 MHz and 37 °C). This bi-functionalized PGd-LNP was administered to three atherosclerotic apoE−/− mice to reveal the clear enhancement of atherosclerotic plaques in the brachiocephalic artery (BA) by MRI, in good agreement with the high accumulation of Gd in the aortic arch as shown by ICP-MS. The parallel in vivo MRI and ex vivo studies of whole mouse cryo-imaging were performed using triply functionalized LNPs with P, Gd, and R (PGdR-LNP). The clear presence of atherosclerotic plaques in BA was observed by ex vivo bright field cryo-imaging, and they were also observed by high emission fluorescent imaging. These directly corresponded to the enhanced tissue in the in vivo MRI of the identical mouse.LDL-mimetic lipid nanoparticles, decorated with MRI contrast agents and fluorescent dyes, were prepared by the covalent attachments of an apoB100-mimetic peptide, Gd(iii)-chelate, and rhodamine to enhance atherosclerosis in the in vivo imaging. 相似文献
222.
Chaudhary Ankita Khanna Garima Chopra Haritma Gaba Ritu 《Research on Chemical Intermediates》2022,48(5):2267-2278
A simple, efficient, and eco-friendly protocol for the synthesis of 1,3-oxazine derivatives, viz. 7-aryl-7,8-dihydro-6H-[1,3]dioxolo[4′,5′:4,5]benzo[1,2-e][1,3]oxazines and 3-aryl-3,4-dihydro-2H- naphtho[2,3-e][1,3]oxazine-5,10-diones, involving one-pot multicomponent condensation reaction of various amines and formaldehyde with sesamol/2-hydroxy-1,4-naphthoquinone, respectively, catalyzed by a choline chloride–oxalic acid deep eutectic solvent has been developed. The method offers several advantages, including mild reaction conditions, simple operating procedure, recyclable and biodegradable catalyst, short reaction times, and excellent yields of the target products.
相似文献223.
Sandip Kumar Samanta Syed Samim Ali Ankita Gangopadhyay Kalipada Maiti Ajoy Kumar Pramanik Uday Narayan Guria 《Supramolecular chemistry》2019,31(5):349-360
A 3-indolylacrylate derivative, 3-IA, prepared by connecting an ethyl acrylate in 3-position of indole has been synthesised and characterised. Ethyl acrylate moiety acts as the Michael acceptor towards H2S, and the resultant addition product then participates in intramolecular cyclisation with the ester group at 2-position to form another new heterocyclic ring. Blue fluorescence of 3-IA turned into green in presence of H2S, leading to ratiometric behaviour of the fluorescent sensor with large stokes shift of 55 nm. Probe 3-IA has excellent selectivity towards H2S over other biothiols and other competing anions. Density function theory/time-dependent density function theory calculations were carried out to validate the reaction mechanism and the electronic properties of 3-IA. Importantly, the ratiometric probe 3-IA shows great promise in H2S detection by simple visual fluorescent inspection in filter paper-based protocol. The probe shows its excellent ability to detect H2S in different natural water samples. Furthermore, we have employed our probe to detect H2S for ratiometric imaging in live Vero cell. 相似文献
224.
Nondumiso P. Dube Xavier Siwe-Noundou Rui W. M. Krause Douglas Kemboi Vuyelwa Jacqueline Tembu Amanda-Lee Manicum 《Molecules (Basel, Switzerland)》2021,26(8)
Species within the genus Rhoicissus (Vitaceae) are commonly used in South African traditional medicine. The current review discusses the occurrence, distribution, traditional uses, phytochemistry, and pharmacological properties of Rhoicissus species covering the period 1981–2020. The data reported were systematically collected, read, and analysed from scientific electronic databases including Scopus, Scifinder, Pubmed, and Google Scholar. Reported evidence indicates that species in this genus are used for the treatment of gastrointestinal complaints, sexually transmitted infections (STIs), and infertility, as well as to tone the uterus during pregnancy and to facilitate delivery. Pharmacological studies have further shown that members of the Rhoicissus genus display antidiabetic, uterotonic, ascaricidal, hepatoprotective, antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. They are linked to the presence of bioactive compounds isolated from the genus. Hence, Rhoicissus species can potentially be an alternative therapeutic strategy to treat diseases and develop safer and more potent drugs to combat diseases. Plant species of this genus have valuable medicinal benefits due to their significant pharmacological potential. However, scientific investigation and information of the therapeutic potential of Rhoicissus remain limited as most of the species in the genus have not been fully exploited. Therefore, there is a need for further investigations to exploit the therapeutic potential of the genus Rhoicissus. Future studies should evaluate the phytochemical, pharmacological, and toxicological activities, as well as the mode of action, of Rhoicissus crude extracts and secondary compounds isolated from the species. 相似文献
225.
Kumar Shiny S. Rao Ankita Yadav K. K. Lenka R. K. Singh D. K. Tomar B. S. 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(1):375-384
Journal of Radioanalytical and Nuclear Chemistry - Present study reports simultaneous batch and column extraction of Pu(IV) and Am(III) followed by selective stripping from actual analytical waste... 相似文献
226.
Nayana Adhikari Ankita Kashyap Anshul Shakya Surajit Kumar Ghosh Dibya Ranjan Bhattacharyya Hans Raj Bhat Udaya Pratap Singh 《Journal of heterocyclic chemistry》2020,57(6):2389-2399
A series of novel PABA-substituted 1,3,5-triazine derivatives were developed via microwave assisted synthesis and subsequently tested for antimalarial activity against chloroquine sensitive 3D7 strain of Plasmodium falciparum using chloroquine as standard. Antimalarial screening result showed that synthesized compounds exhibited IC50 in the range of 4.46 to 79.72 μg mL−1. Among the tested compounds, 4c and 4f showed significant antimalarial activity with low binding energies (BE) -172.32 and 160.41 kcal mol−1 via interacting with Arg122 through the involvement of COOH of the phenyl linked to 1,3,5-triazine. In conclusion, these core scaffolds can be used for future antimalarial drug development. 相似文献
227.
Themba Dube 《Algebra Universalis》2018,79(1):7
For any semisimple f-ring A with bounded inversion, we show that the frame of radical ideals of A and the frame of z-ideals of A have isomorphic subfit coreflections. If we assume the Axiom of Choice, then the two coreflections are actually identical. If the f-ring has the property that the sum of two z-ideals is a z-ideal (as in the case of rings of continuous functions), then the epicompletion of the frame of z-ideals is shown to be a dense quotient of the epicompletion of the frame of radical ideals. Baer rings, exchange rings, and normal rings that lie in the class of semisimple f-rings with bounded inversion are shown to have characterizations in terms of frames of z-ideal which are similar to characterizations in terms of frames of radical ideals. 相似文献
228.
Ren Tschaggelar Besnik Kasumaj Maria Grazia Santangelo Jrg Forrer Patrik Leger Henry Dube Franois Diederich Jeffrey Harmer Rolf Schuhmann Ins García-Rubio Gunnar Jeschke 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2009,200(1):81-87
The construction and performance of a cryogenic 35 GHz pulse electron nuclear double resonance (ENDOR) probehead for large samples is presented. The resonator is based on a rectangular TE102 cavity in which the radio frequency (rf) B2-field is generated by a two turn saddle ENDOR coil crossing the resonator along the sample axis with minimal distance to the sample tube. An rf power efficiency factor is used to define the B2-field strength per square-root of the transmitted rf power over the frequency range 2–180 MHz. The distributions of the microwave B1- and E1-field, and the rf B2-field are investigated by electromagnetic field calculations. All dielectrics, the sample tube, and coupling elements are included in the calculations. The application range of the probehead and the advantages of using large sample sizes are demonstrated and discussed on a number of paramagnetic samples containing transition metal ions. 相似文献
229.
In a sequential three-component coupling syncarpic acid, 3-methylbutanal and an acylated phloroglucinol were combined to the hydroxy ketone 3. Acid catalysis converted 3 directly to the natural product rhodomyrtosone B (2). The other isomer, the antibiotic rhodomyrtone (1) was obtained from 3 in a sequence of acid-catalyzed cyclization, retro Friedel–Crafts reaction, and reacylation. In preliminary assays both compounds showed potent antibiotic activity. 相似文献
230.
The field of hypervalent iodine chemistry has been prevalent since 1886. Its journey from obscurity to coming into the limelight has witnessed many effective transformations which have benefited the synthetic community at large. The reactivity of primary amines with hypervalent iodine reagents causes difficulty in synthetic outcome or not feasible due to high exothermicity of amine iodine which is an acid base reaction. This minireview highlights the worthwhile reactivity of hypervalent iodine reagents with aromatic and aliphatic primary amines. Some recent literature has been discussed to make a clear understanding on how such high reactivity of primary amine is controlled by introducing modulation in either substrate or reaction conditions, most of which are carried out under ambient reaction conditions. 相似文献