排序方式: 共有39条查询结果,搜索用时 15 毫秒
21.
22.
23.
The structural and electronic transport properties of La1−x
Ce
x
MnO3 (x=0.0–1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with
Ce doping. They also make a metal-insulator transition (MIT) and transition temperature increases with increase in Ce concentration
up to 50% doping. The system La0.5Ce0.5MnO3 also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition. 相似文献
24.
25.
Gayathri R. Ediriweera Joshua D. Simpson Adrian V. Fuchs Taracad K. Venkatachalam Matthias Van De Walle Christopher B. Howard Stephen M. Mahler James P. Blinco Nicholas L. Fletcher Zachary H. Houston Craig A. Bell Kristofer J. Thurecht 《Chemical science》2020,11(12):3268
There remain several key challenges to existing therapeutic systems for cancer therapy, such as quantitatively determining the true, tissue-specific drug release profile in vivo, as well as reducing side-effects for an increased standard of care. Hence, it is crucial to engineer new materials that allow for a better understanding of the in vivo pharmacokinetic/pharmacodynamic behaviours of therapeutics. We have expanded on recent “click-to-release” bioorthogonal pro-drug activation of antibody-drug conjugates (ADCs) to develop a modular and controlled theranostic system for quantitatively assessing site-specific drug activation and deposition from a nanocarrier molecule, by employing defined chemistries. The exploitation of quantitative imaging using positron emission tomography (PET) together with pre-targeted bioorthogonal chemistries in our system provided an effective means to assess in real-time the exact amount of active drug administered at precise sites in the animal; our methodology introduces flexibility in both the targeting and therapeutic components that is specific to nanomedicines and offers unique advantages over other technologies. In this approach, the in vivo click reaction facilitates pro-drug activation as well as provides a quantitative means to investigate the dynamic behaviour of the therapeutic agent.There remain several key challenges to existing therapeutic systems for cancer therapy, such as quantitatively determining the true, tissue-specific drug release profile in vivo, as well as reducing side-effects for an increased standard of care. 相似文献
26.
In this study, three profluorescent nitroxides 1,1,3,3-tetramethyldibenzo[e,g]isoindolin-2-yloxyl (TMDBIO), 1,1,3,3-tetramethyl-2,3-dihydro-2-azaphenalene-2-yloxyl (TMAO) and 5-[2-(4-methoxycarbonyl-phenyl)-ethenyl]1,1,3,3-tetramethylisoindoline-2-yloxyl (MeCSTMIO) were tested as probes for radical-mediated damage in polypropylene arising from both UV and thermally initiated sources. These nitroxides possess a very low fluorescence quantum yield due to quenching by the nitroxide group; however, when the free-radical moiety is removed by reaction with alkyl radicals (to give an alkoxyamine), strong fluorescence is observed. The results obtained from this profluorescent nitroxide trapping technique compare favourably with other methods of monitoring degradation, provided the appropriate probe is chosen for the conditions of oxidation, signalling an indication of damage well before other techniques show any response. The technique was also applied to the monitoring of crosslinked polyester coating resins. Differentiation in the oxidative stability of the resins was evident after as little as 200 min where other monitoring techniques require up to 300 h of accelerated degradation. This highlights the sensitivity of this method as well as demonstrating the scope of this technique to assess polymer stability. 相似文献
27.
Jan P. Menzel Florian Feist Bryan Tuten Tanja Weil James P. Blinco Christopher Barner‐Kowollik 《Angewandte Chemie (International ed. in English)》2019,58(22):7470-7474
We report light‐induced reactions in a two‐chromophore system capable of sequence‐independent λ‐orthogonal reactivity relying solely on the choice of wavelength and solvent. In a solution of water and acetonitrile, LED irradiation at λmax=285 nm leads to full conversion of 2,5‐diphenyltetrazoles with N‐ethylmaleimide to the pyrazoline ligation products. Simultaneously present o‐methylbenzaldehyde thioethers are retained. Conversely, LED irradiation at λmax=382 nm is used to induce ligation of the o‐methylbenzaldehydes in acetonitrile with N‐ethylmaleimide via o‐quinodimethanes, while 2,5‐diphenyltetrazoles also present are retained. This unprecedented photochemical selectivity is achieved through control of the number and wavelength of incident photons as well as favorable optical properties and quantum yields of the reactants in their environment. 相似文献
28.
29.
30.