排序方式: 共有28条查询结果,搜索用时 169 毫秒
1.
Recently, Gill and Chien introduced a new radial quadrature for multiexponential integrands (MultiExp grid) to deal with the radial part of the numerical integration. In this article, the MultiExp grid is studied and used to integrate the charge density. The MultiExp grid, along with an optimal pruning scheme, performed very well both in terms of accuracy and efficiency compared to other radial mappings commonly used in Density Functional Theory. 相似文献
2.
Zhongxian Fan Jiaen Xie Dr. Tumpa Sadhukhan Chao Liang Can Huang Wenqing Li Tingxuan Li Dr. Pingyu Zhang Dr. Samya Banerjee Dr. Krishnan Raghavachari Dr. Huaiyi Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(3):e202103346
Four photo-catalysts of the general formula [Ir(CO6/ppy)2(L)]Cl where CO6=coumarin 6 ( Ir1 – Ir3 ), ppy=2-phenylpyridine ( Ir4 ), L=4′-(3,5-di-tert-butylphenyl)-2,2′ : 6′,2′′-terpyridine ( Ir1 ), 4′-(3,5-bis(trifluoromethyl)phenyl)-2,2′ : 6′,2′′-terpyridine ( Ir2 and Ir4 ), and 4-([2,2′ : 6′,2′′-terpyridin]-4′-yl)-N,N-dimethylaniline ( Ir3 ) were synthesized and characterized. These photostable photo-catalysts ( Ir1 – Ir3 ) showed strong visible light absorption between 400–550 nm. Upon light irradiation (465 and 525 nm), Ir1 – Ir3 generated singlet oxygen and induced rapidly photo-catalytic oxidation of cellular coenzymes NAD(P)H. Ir1 – Ir3 showed time-dependent cellular uptake with excellent intracellular retention efficiency. Upon green light irradiation (525 nm), Ir2 provided a much higher photo-index (PI=793) than the clinically used photosensitizer, 5-aminolevulinicacid (5-ALA, PI>30) against HeLa cancer cells. The observed necro-apoptotic anticancer activity of Ir2 was due to the Ir2 triggered photo-induced intracellular redox imbalance (by NAD(P)H oxidation and ROS generation) and change in the mitochondrial membrane potential. Remarkably, Ir2 showed in vivo photo-induced catalytic anticancer activity in mouse models. 相似文献
3.
Ganghao Liang Dr. Tumpa Sadhukhan Dr. Samya Banerjee Dongsheng Tang Hanchen Zhang Minhui Cui Nicolás Montesdeoca Dr. Johannes Karges Prof. Dr. Haihua Xiao 《Angewandte Chemie (International ed. in English)》2023,62(22):e202301074
The development of PtIV prodrugs that are reduced into the therapeutically active PtII species within the tumor microenvironment has received much research interest. In order to provide spatial and temporal control over the treatment, there is a high demand for the development of compounds that could be selectively activated upon irradiation. Despite recent progress, the majority of PtIV complexes are excited with ultraviolet or blue light, limiting the use of such compounds to superficial application. To overcome this limitation, herein, the first example of PtIV prodrug nanoparticles that could be reduced with deeply penetrating ultrasound radiation is reported, enabling the treatment of deep-seated or large tumors. The nanoparticles were found to selectively accumulate inside a mouse colon carcinoma tumor upon intravenous injection and were able to eradicate the tumor upon exposure to ultrasound radiation. 相似文献
4.
Spectrophotometric, spectrofluorometric and HPLC determination of desloratadine in dosage forms and human plasma 总被引:1,自引:0,他引:1
Four sensitive, simple and specific methods were developed for the determination of desloratadine (DSL), a new antihistaminic drug in pharmaceutical preparations and biological fluids. Methods I and II are based on coupling DSL with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in borate buffer of pH 7.6 where a yellow colored reaction product was obtained and measured spectrophotometrically at 485 nm (Method I). The same product could be measured spectrofluorometrically at 538 nm after excitation at 480 nm (Method II). Methods III and IV, on the other hand, involved derivatization of DSL with 2,4-dinitrofluorobenzene (DNFB) in borate buffer of pH 9.0 producing a yellow colored product that absorbs maximally at 375 nm (Method III). The same derivative was determined after separation adopting HPLC (Method IV). The separation was performed on a column packed with cyanopropyl bonded stationary phase equilibrated with a mobile phase composed of acetonitrile-water (60 : 40, v/v) at a flow rate of 1.0 ml min(-1) with UV detection at 375 nm. The calibration curves were linear over the concentration ranges of 0.5-6, 0.02-0.4, 1-10 and 1-30 microg ml(-1) for Methods I, II, III and IV, respectively. The lower detection limits (LOD) were 0.112, 0.004, 0.172 and 0.290 microg ml(-1), respectively, for the four methods. The limits of quantification (LOQ) were 0.340, 0.012, 0.522 and 0.890 microg ml(-1) for Methods I, II, III and IV, respectively. The proposed methods were applied to the determination of desloratadine in its tablets and the results were in agreement with those obtained using a reference method. Furthermore, the spectrofluorometric method (Method II) was extended to the in-vitro determination of the drug in spiked human plasma, with a mean percentage recovery (n=4) of 99.7+/-3.54. Interference arising from endogenous amino acids has been overcome using solid phase extraction. The proposed methods are highly specific for determination of DSL in the presence of the parent drug loratadine. A proposal for the reaction pathways is postulated. 相似文献
5.
Sk. Sheriff Shah Maniklal Shee Yarra Venkatesh Amit Kumar Singh Samya Samanta Prof. N. D. Pradeep Singh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(17):3703-3708
The combination of an organic photocatalyst [4CzIPN (1,2,3,5-tetrakis(carbazol-9-yl)-4,6 dicyanobenzene) or 5MeOCzBN (2,3,4,5,6-pentakis(3,6-dimethoxy-9 H-carbazol-9-yl)benzonitrile)], quinuclidine, and tetra-n-butylammonium phosphate (hydrogen-bonding catalyst) was employed for amide bond formations. The hydrogen-bonded OH group activated the adjacent C−H bond of alcohols towards hydrogen atom transfer (HAT) by a radical species. The quinuclidinium radical cation, generated through single-electron oxidation of quinuclidine by the photocatalyst, employed to abstract a hydrogen atom from the α-C−H bond of alcohols selectively due to a polarity effect-produced α-hydroxyalkyl radical, which subsequently converted to the corresponding aldehyde under aerobic conditions. Then the coupling of the aldehyde and an amine formed a hemiaminal intermediate that upon photocatalytic oxidation produced the amide. 相似文献
6.
Ali H. Abu Almaaty Eslam E. M. Toson El-Sherbiny H. El-Sayed Mohamed A. M. Tantawy Eman Fayad Ola A. Abu Ali Islam Zaki 《Molecules (Basel, Switzerland)》2021,26(6)
A novel series of N-1 arylidene amino imidazole-2-thiones were synthesized, identified using IR, 1H-NMR, and 13C-NMR spectral data. Cytotoxic effect of the prepared compounds was carried out utilizing three cancer cell lines; MCF-7 breast cancer, HepG2 liver cancer, and HCT-116 colon cancer cell lines. Imidazole derivative 5 was the most potent of all against three cell lines. DNA flow cytometric analysis showed that, imidazoles 4d and 5 exhibit pre-G1 apoptosis and cell cycle arrest at G2/M phase. The results of the VEGFR-2 and B-Raf kinase inhibition assay revealed that compounds 4d and 5 displayed good inhibitory activity compared with reference drug erlotinib. 相似文献
7.
Yanhua Xu Samya Sen Qiong Wu Xujia Zhong Randy H. Ewoldt Steven C. Zimmerman 《Chemical science》2020,11(12):3326
A new type of base-triggered self-amplifying degradable polyurethane is reported that degrades under mild conditions, with the release of increasing amounts of amine product leading to self-amplified degradation. The polymer incorporates a base-sensitive Fmoc-derivative into every repeating unit to enable highly sensitive amine amplified degradation. A sigmoidal degradation curve for the linear polymer was observed consistent with a self-amplifying degradation mechanism. An analogous cross-linked polyurethane gel was prepared and also found to undergo amplified breakdown. In this case, a trace amount of localized base initiates the degradation, which in turn propagates through the material in an amplified manner. The results demonstrate the potential utility of these new generation polyurethanes in enhanced disposability and as stimuli responsive materials.A new type of base-triggered self-amplifying degradable polyurethane is reported that degrades under mild conditions, with the release of increasing amounts of amine product leading to self-amplified degradation. 相似文献
8.
Dr. Samir Kumar Sarkar Rinkumoni Chaliha Dr. Mujahuddin M. Siddiqui Dr. Samya Banerjee Annika Münch Dr. Regine Herbst-Irmer Prof. Dietmar Stalke Prof. Dr. Eluvathingal D. Jemmis Prof. Herbert W. Roesky 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23215-23219
We report the design, synthesis, structure, bonding, and reaction of a neutral 2π aromatic three-membered disilaborirane. The disilaborirane is synthesized by a facile one-pot reductive dehalogenation of amidinato-silylene chloride and dibromoarylborane with potassium graphite. Despite the tetravalent arrangement of atoms around silicon, the three-membered silicon-boron-silicon ring is aromatic, as evidenced by NMR spectroscopy, nucleus independent chemical shift calculations, first-principles electronic structure studies using density functional theory (DFT) and natural bond orbital (NBO) based bonding analysis. Trimethylsilylnitrene, generated in situ, inserts in the Si−Si bond of disilaborirane to obtain a four-membered heterocycle 1-aza-2,3-disila-4-boretidine derivative. Both the heterocycles are fully characterized by X-ray crystallography. 相似文献
9.
Banerjee S Prasad P Hussain A Khan I Kondaiah P Chakravarty AR 《Chemical communications (Cambridge, England)》2012,48(62):7702-7704
Curcumin (Hcur) as a cellular imaging and PDT agent shows remarkable photocytotoxicity in HeLa cells in visible light of 400-700 nm giving IC(50) = 8.2 ± 0.2 μM and its degradation is arrested on formation of photocytotoxic dipyridophenazine (dppz) complex [VO(cur)(dppz)Cl] (IC(50) = 3.3 ± 0.4 μM), while both are less toxic in the dark. 相似文献
10.
We investigate several fluctuation effects in high-energy hadronic and nuclear collisions through the analysis of different
observables. To introduce fluctuations in the initial stage of collisions, we use the interacting gluon model (IGM) modified
by the inclusion of the impact parameter. The inelasticity and leading-particle distributions follow directly from this model.
The fluctuation effects on rapidity distributions are then studied using Landau's hydrodynamic model in one dimension. To
investigage further the effects of the multiplicity fluctuation, we use the longitudinal phase-space model, with the multiplicity
distribution calculated within the hydrodynamic model, and the initial conditions given by the IGM. Forward-backward correlation
is obtained in this way. 相似文献