排序方式: 共有104条查询结果,搜索用时 62 毫秒
81.
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
82.
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83.
Nilimesh Das Subhrasmita Sahu Tanmoy Khan Pratik Sen 《Photochemistry and photobiology》2023,99(2):538-546
Conformational heterogeneity is a defining characteristic of a protein and is vital in understanding its function and folding landscape. In the present work, we interrogated the presence of conformational heterogeneity in multi-domain human serum albumin in a domain-specific manner using red edge excitation shift (REES) in its native state and also monitored its variation along the unfolding transition. We also looked into the origin of such conformational heterogeneity by varying the solution viscosity. We observed (1) even in the native state, the heterogeneity and dynamics of the side chain exhibit varied behaviors depending on which domain of the multi-domain human serum albumin (HSA) is being examined. (2) When the protein is in the unfolded state, the extent of REES is rendered unimportant since there is a greater quantity of free water present, in addition to the disruption of the protein's structure. (3) While the rigid protein matrix provides the rigidity of domain-I and domain-III, the rigidity of domain-II is provided by water molecules, which indicates that the role of water molecules in providing the rigidity is significant. Overall, our results provide direct evidence of the rigidity and alternate side chain packing arrangement of protein core that varies domain-wise in multi-domain HSA. 相似文献
84.
Predicting the redox properties of uranyl complexes using electronic structure calculations
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Bharti Khungar Ankita Roy Anand Kumar Biswajit Sadhu Mahesh Sundararajan 《International journal of quantum chemistry》2017,117(12)
A plethora of chemical reactions is redox driven processes. The conversion of toxic and highly soluble U(VI) complexes to nontoxic and insoluble U(IV) form are carried out through proton coupled electron transfer by iron containing cytochromes and mineral surfaces such as machinawite. This redox process takes place through the formation of U(V) species which is unstable and immediately undergo the disproportionation reaction. Thus, theoretical methods are extremely useful to understand the reduction process of U(VI) to U(V) species. We here have carried out the structures and reduction properties of several U(VI) to U(V) complexes using a variety of electronic structure methods. Due to the lack of experimental ionization energies for uranyl (UO2(V)‐UO2(VI)) couple, we have benchmarked the current and popularly used density functionals and cost effective ab initio methods against the experimental electron detachment energies of [UO2F4]1‐/2‐ and [UO2Cl4]1‐/2‐. We find that electron detachment energy of U(VI) predicted by RI‐MP2 level on the BP86 geometries correlate nicely with the experimental and CCSD(T) data. Based on our benchmark studies, we have predicted the structures and electron detachment energies of U(V) to U(VI) species for a series of uranium complexes at the RI‐MP2//BP86 level which are experimentally inaccessible till date. We find that the redox active molecular orbital is ligand centered for the oxidation of U(VI) species, where it is metal centered (primarily f‐orbital) for the oxidation of U(V) species. Finally, we have also calculated the detachment energies of a known uranyl [UO2]1+ complex whose X‐ray crystal structures of both oxidation states are available. The large bulky nature of the ligand stabilizing the uncommon U(V) species which cannot be routinely studied by present day CCSD(T) methods as the system size are more than 20–30 atoms. The success of our efficient computational strategy can be experimentally verified in the near future for the complex as the structures are stable in gas phase which can undergo oxidation. 相似文献
85.
Molecular‐Recognition‐Assisted pKa Shifts and Metal‐Ion‐Induced Fluorescence Regeneration in p‐Sulfonatocalix[6]arene‐Encapsulated Acridine
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Ankita Jadhav Vrashali S. Kalyani Dr. Nilotpal Barooah Dr. Dipalee D. Malkhede Dr. Jyotirmayee Mohanty 《Chemphyschem》2015,16(2):420-427
The host–guest interactions of cationic (AcH+) and neutral (Ac) forms of the dye acridine with the macrocyclic host p‐sulfonatocalix[6]arene (SCX6) were investigated by using ground‐state absorption, steady‐state and time‐resolved fluorescence, and NMR measurements. The cationic form undergoes significant complexation with SCX6 (Keq=2.5×104 M ?1), causing a sharp decrease in the fluorescence intensity and severe quenching in the excited‐state lifetime of the dye. The strong binding of the AcH+ form of the dye with SCX6 is attributed to ion–ion interactions involving the sulfonato groups (SO3?) of SCX6 and the positively charged AcH+ at pH of approximately 4.3. Whereas, the neutral Ac form of the dye undergoes weak complexation with SCX6 (Keq=0.9×103 M ?1) and the binding constant is lowered by one order of magnitude compared with that of the SCX6–AcH+ system. The strong affinity of SCX6 to the protonated form leads to a large upward pKa shift (≈2 units) in the dye. In contrast, strong emission quenching upon SCX6 interaction and the regeneration of fluorescence intensity of the dye in the presence of Gd3+ through competitive binding have also been demonstrated. 相似文献
86.
Madhukar S. Said Ashish A. Chinchansure Laxman Nawale Ankita Durge Ashish Wadhwani Smita S. Kulkarni 《Natural product research》2015,29(22):2080-2086
Phytochemical investigation of the methanol extract of the aerial parts of Polygonum glabrum afforded one new natural product ( ? )-2-methoxy-2-butenolide-3-cinnamate (1) along with six known compounds, β-hydroxyfriedalanol (2), 3-hydroxy-5-methoxystilbene (3), ( ? ) pinocembrin (4), sitosterol-(6′-O-palmitoyl)-3-O-β-d-glucopyranoside (5), ( ? ) pinocembrin-5-methyl ether (6) and sitosterol-3-O-β-d-glucopyranoside (7). Compound 1 showed promising in vitro anti-HIV-1 activity against primary isolates HIV-1UG070 (X4, subtype D) and HIV-1VB59 (R5, subtype C) assayed using TZM-bl cell line with IC50 in the range of 15.68–22.43 μg/mL. The extract showed TI in the range of 19.19–27.37 with IC50 in the range of 10.90–15.55 μg/mL. Compounds 1, 3 and 4 exhibited in vitro anti-mycobacterium activity against Mycobacterium tuberculosis H37Ra with IC50 values of 1.43, 3.33 and 1.11 μg/mL in dormant phase and 2.27, 3.33 and 1.21 μg/mL in active phase, respectively. Compound 4 was found to be the most active antiproliferative with IC50 values of 1.88–11.00 μg/mL against THP-1, A549, Panc-1, HeLa and MCF7 cell lines. 相似文献
87.
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
88.
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
89.
Manorama Singh Smita R. Bhardiya Ambika Asati Harendra Sheshma Ankita Rai Vijai K. Rai 《Electroanalysis》2021,33(2):464-472
Herein, we report construction of a ferrocene-reduced graphene oxide-Mn spinel modified glassy carbon electrode (Fc−G/Mn3O4/GCE) as a sensitive electrochemical probe for hydrazine detection via its oxidation. The synergistic effect of ferrocene, graphene oxide and Mn3O4 provides it a great electrocatalytic effect. The electrochemical investigations of Fc−G/Mn3O4/GCE were studied using cyclic voltammetry, while differential pulse voltammetry was utilized for recording the electrocatalytic sensing of hydrazine. The prepared Fc−G/Mn3O4 offers a platform for sensitive and selective detection of low-level hydrazine in two linear ranges from 0.045 to 108 μM and 108 to 653 μM with limit of detection 8.5 nM. Real sample analysis was also performed in local industrial water samples with satisfactory recovery results. 相似文献
90.
A catalyst-free multicomponent reaction (MCR) capable of affording a wide range of novel benzo[a][1,3]oxazino[6,5-c]phenazine derivatives via one pot two-step domino protocol, in water is reported. Catalyst-free conditions along with green solvent system make the process ecofriendly as well as economical. Simple reaction conditions, easy work-up isolation, and purification of products are the significant advantages of the present protocol. 相似文献