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排序方式: 共有309条查询结果,搜索用时 15 毫秒
1.
A Zinc(II) Photocage Based on a Decarboxylation Metal Ion Release Mechanism for Investigating Homeostasis and Biological Signaling 下载免费PDF全文
Dr. Prem N. Basa Sagar Antala Prof. Dr. Robert E. Dempski Prof. Dr. Shawn C. Burdette 《Angewandte Chemie (International ed. in English)》2015,54(44):13027-13031
Metal ion signaling in biology has been studied extensively with ortho‐nitrobenzyl photocages; however, the low quantum yields and other optical properties are not ideal for these applications. We describe the synthesis and characterization of NTAdeCage, the first member in a new class of Zn2+ photocages that utilizes a light‐driven decarboxylation reaction in the metal ion release mechanism. NTAdeCage binds Zn2+ with sub‐pM affinity using a modified nitrilotriacetate chelator and exhibits an almost 6 order of magnitude decrease in metal binding affinity upon uncaging. In contrast to other metal ion photocages, NTAdeCage and the corresponding Zn2+ complex undergo efficient photolysis with quantum yields approaching 30 %. The ability of NTAdeCage to mediate the uptake of 65Zn2+ by Xenopus laevis oocytes expressing hZIP4 demonstrates the viability of this photocaging strategy to execute biological assays. 相似文献
2.
Ashok Kumar Bharati Prem Lama Joanna Trojan–Piegza Alina Bieńko 《Journal of Coordination Chemistry》2017,70(24):3959-3970
Assembly of orotic acid (H3Or, 1,2,3,6-tetrahydro-2,6-dioxo-4-pyrimidinecarboxylic) and Cd(NO3)·6H2O yielded a coordination polymer, [(Cd(Hor)·2.5H2O)2]n (1), which has been characterized by X-ray single-crystal diffraction, TGA, and ?uorescence spectra. Single-crystal X-ray structural analyses reveal that 1 is a hydrogen-bonded binuclear Cd-orotate coordination polymer in which both Cd2+ ions have different coordination environments with identical distorted octahedral geometry. Crystal data for 1: monoclinic, space group P21/n, a = 7.0209(10) Å, b = 13.974(2) Å, c = 17.541(3) Å, β = 98.842(2)°, V = 1700.5(4) Å, Z = 4, R1 = 0.0269, wR2 = 0.0612, θmax = 25.960. The emission spectrum of the Cd-complex recorded with 265 nm excitation wavelength reveals the complex has strong blue luminescence with the peak maximum 420 nm (2.95 eV) as a result of the n–π* and π–π* transitions on the H3Or ligand. 相似文献
3.
Harun Muhammad Arif Bin Gunnasegaran Prem A./L. Sidik Nor Azwadi Che Beriache M’hamed Ghaderian Javad 《Journal of Thermal Analysis and Calorimetry》2021,144(4):1435-1449
Journal of Thermal Analysis and Calorimetry - High heat generation from electronic devices needs to cool down properly to prevent overheating. Loop heat pipe (LHP) is one of the excellent cooling... 相似文献
4.
Novel montmorillonite-based ceramic membrane (CM) has been prepared with poly(vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP) copolymer as binder. Physical properties such as surface morphology, porosity, liquid electrolyte uptake and thermal stability were analysed. The ceramic membrane was activated by soaking it in a non-aqueous liquid electrolyte (1.0 M LiPF6 solution in 1/1 v/v ethylene carbonate/diethyl carbonate mixture) for 10 min. The compatibility of the membrane with lithium metal anode as a function of storage time was analysed by assembling a Li/CM/Li symmetric cell. Finally, a lab-scale cell composed of Li/CM/LiFePO4 is assembled and its cycling performance analysed at different C-rates. Although the ceramic membrane is not flexible, it shows high thermal stability and stable interfacial properties when in contact with the lithium metal anode. A stable cycling behaviour is demonstrated even at 1C-rate with limited fade in capacity. 相似文献
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Comparative studies on radiolytic degradation of deuterium labeled and unlabeled tributyl phosphates
Shikha Sharma Sunil K. Ghosh Devidas B. Naik Prem S. Dhami Joti N. Sharma 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):583-591
Deuterium labeled tributyl phosphates were synthesized and their solutions in n-dodecane have been investigated for γ-radiolytic degradation up to an absorbed dose of 2,000 kGy from a 60Co source. The performance was compared with undeuterated TBP. Radiolysis extent and pattern of formation of major degradation products, viz. dibutyl hydrogen phosphate and monobutyl dihydrogen phosphate were found to be very similar from deuterated or undeuterated samples. Extraction behavior for UO2 2+ and Pu(IV) was studied after the radiolysis, and the results showed similarity in extraction/stripping behavior for all labeled or unlabeled TBP samples. The isotope effect (k H/k D) observed is minimal in this γ-radiolytic degradation study. 相似文献
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This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces. 相似文献
9.
M. L. Keshtov V. S. Kochurov Ganesh Datt Sharma A. R. Khokhlov 《Polymer Science Series B》2013,55(5-6):373-381
Two new donor-acceptor narrow-band-gap photovoltaic copolymers containing various electron-acceptor functional groups, such as thienopyrazine and thienodithiazole derivatives, are synthesized under the conditions of the Suzuki polycondensation reaction and characterized via 1H NMR spectroscopy and GPC. The optical, electrochemical, and photovoltaic properties of the polymers are examined in detail. Both copolymers have good solubilities, high thermal stabilities, broad absorption regions (350–950 nm), relatively low levels of the highest occupied molecular orbital (?5.01 and ?5.02 eV for polymers I and II, respectively), and narrow band gaps (1.31 and 1.41 eV, respectively). Photovoltaic devices based on a polymer-II-PC60BM (1: 3, wt/wt) mixture under AM 1.5 irradiation of 100 mV/cm2 exhibit a power-conversion efficiency of ~0.29%, a short-circuit current of 1.45 mA/cm2, an open-circuit voltage of V oc = 0.67 V, and a fill factor of 0.30. These results are evidence that thienopyrazine functional groups are attractive as electron-acceptor building blocks in organic electronics. 相似文献
10.
Electronic structure of the interface between a bathocuproine (BCP) molecule and metal surface was studied by density functional theory. The bond energy of BCP with metal surface increased with decreasing work function of metals, that is, Au, Ag, Al, Mg, and Ca in this order. The charge transfer also increased with decreasing metal work function. It was analyzed that the Fermi level and the lowest unoccupied molecular orbital of BCP are composed of both BCP and metal orbital component, and electron transport properties across the BCP and metal is discussed based on these analyses. 相似文献