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181.
A unique combined and multi‐disciplinary wavelength multiplexed spectrometer is described. It is furnished with high‐sensitivity imaging plate detectors, the power to which can be gated to provide time‐resolved data. The system is capable of collecting spectrally resolved luminescence data following X‐ray excitation [radioluminescence (RL) or X‐ray excited optical luminescence (XEOL)], electron irradiation [cathodoluminescence (CL)] and visible light from light emitting diodes (LEDs) [photoluminescence (PL)]. Time‐resolved PL and CL data can be collected to provide lifetime estimates with half‐lives from microsecond timeframes. There are temperature stages for the high and low temperature experiments providing temperature control from 20 to 673 K. Combining irradiation, time resolved (TR) and TR‐PL allows spectrally‐resolved thermoluminescence (TL) and optically stimulated luminescence (OSL). The design of two detectors with matched gratings gives optimum sensitivity for the system. Examples which show the advantages and multi‐use of the spectrometer are listed. Potential future experiments involving lifetime analysis as a function of irradiation, dose and temperature plus pump‐probe experiments are discussed. 相似文献
182.
Satoshi Morimoto Kenichi Hongo Yoichiro Kusakari Kimiaki Komukai Makoto Kawai Jin O-Uchi Hiroyuki Nakayama Michio Asahi Kinya Otsu Michihiro Yoshimura Satoshi Kurihara 《Cell calcium》2014
The Ca2+ content in the sarcoplasmic reticulum (SR) determines the amount of Ca2+ released, thereby regulating the magnitude of Ca2+ transient and contraction in cardiac muscle. The Ca2+ content in the SR is known to be regulated by two factors: the activity of the Ca2+ pump (SERCA) and Ca2+ leak through the ryanodine receptor (RyR). However, the direct relationship between the SERCA activity and Ca2+ leak has not been fully investigated in the heart. In the present study, we evaluated the role of the SERCA activity in Ca2+ leak from the SR using a novel saponin-skinned method combined with transgenic mouse models in which the SERCA activity was genetically modulated. In the SERCA overexpression mice, the Ca2+ uptake in the SR was significantly increased and the Ca2+ transient was markedly increased. However, Ca2+ leak from the SR did not change significantly. In mice with overexpression of a negative regulator of SERCA, sarcolipin, the Ca2+ uptake by the SR was significantly decreased and the Ca2+ transient was markedly decreased. Again, Ca2+ leak from the SR did not change significantly. In conclusion, the selective modulation of the SERCA activity modulates Ca2+ uptake, although it does not change Ca2+ leak from the SR. 相似文献
183.
Determination of amlodipine using terbium‐sensitized luminescence in the presence of europium(III) as a co‐luminescence reagent 下载免费PDF全文
Salma M. Z. Al‐Kindy Abdalla Al‐Snedi Fakhr Eldin O. Suliman Haidar A. J. Al‐Lawati 《Luminescence》2014,29(6):657-662
A sensitive time‐resolved luminescence method for the determination of amlodipine (AM) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+) by formation of a ternary complex with AM in the presence of tri‐n‐octylphosphine oxide (TOPO) as co‐ligand, dodecylbenzenesulfate as surfactant and europium ion as a co‐luminescence reagent. The signal for Tb–AM–TOPO is monitored at λex = 242 nm and λem = 550 nm. Optimum conditions for the formation of the complex in aqueous system were 0.015 m Tris (hydroxylmethyl) amino methane buffer, pH 9.0, TOPO (1.0 × 10–4 m ), Eu3+ (2.0 × 10–7 m ), dodecylbenzenesulfate (0.14%) and 6.0 × 10–5 m of Tb3+, which allows the determination of 10–50 ppb of AM with a limit of detection of 1.2 ppb. The relative standard deviations of the method range between 0.1 and 0.2% indicated excellent reproducibility of the method. The proposed method was successfully applied for the assay of AM in pharmaceutical formulations and in plasma samples. Average recoveries of 98.5 ± 0.2% and 95.2 ± 0.2% were obtained for AM in tablet and plasma samples respectively. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
184.
To explore the relationship between the structure of the ligands and the luminescent properties of the lanthanide complexes, luminescent lanthanide complexes of a new tripodal ligand, featuring N‐thenylsalicylamide arms, were synthesized and characterized by elemental analysis, IR and TGA measurements. Photophysical properties of the complexes were studied by means of UV ? visible absorption and steady‐state luminescence spectroscopy. The results of UV ? vis spectra indicate that metal binding does not disturb the electronic structure of the ligand. Excited‐state luminescence lifetimes and quantum yields of the complexes were determined. The photoluminescence analysis suggested that there is an efficient ligand ? Ln(III) energy transfer for the Tb(III) complex, and the ligand is an efficient 'antenna' for Tb(III). From a more general perspective, the results demonstrated the potential application of the lanthanide complex as luminescent materials in material chemistry. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
185.
Background
In recent years, as our understanding of the various roles played by Ca2 + signaling in development and differentiation has expanded, the challenge of imaging Ca2 + dynamics within living cells, tissues, and whole animal systems has been extended to include specific signaling activity in organelles and non-membrane bound sub-cellular domains.Scope of review
In this review we outline how recent advances in genetics and molecular biology have contributed to improving and developing current bioluminescence-based Ca2 + imaging techniques. Reporters can now be targeted to specific cell types, or indeed organelles or domains within a particular cell.Major conclusions
These advances have contributed to our current understanding of the specificity and heterogeneity of developmental Ca2 + signaling. The improvement in the spatial resolution that results from specifically targeting a Ca2 + reporter has helped to reveal how a ubiquitous signaling messenger like Ca2 + can regulate coincidental but different signaling events within an individual cell; a Ca2 + signaling paradox that until now has been hard to explain.General significance
Techniques used to target specific reporters via genetic means will have applications beyond those of the Ca2 + signaling field, and these will, therefore, make a significant contribution in extending our understanding of the signaling networks that regulate animal development. This article is part of a Special Issue entitled Biochemical, biophysical and genetic approaches to intracellular calcium signalling. 相似文献186.
A mathematical model is built for the kinetics of delayed luminescence, considering the states of the donor and acceptor sides of photosystem II and the electrochemical gradient on the thylakoid membrane. It is used to assess the possible mechanisms of the experimentally observed biphasic changes in delayed luminescence caused by variation potentials (Sukhov et al., Biophysics 53 (3), 223 (2008)). 相似文献
187.
The motilin receptor (MTLR) is an important therapeutic target for the treatment of hypomotility disorders but desensitization may limit its clinical utility. The aim of this study was to investigate the role of the C-terminal tail of the MTLR in the desensitization, phosphorylation and internalization process. Three MTLR mutants, C-terminally truncated from amino acid 412 till 384 (MTLRDelta385), 374 (MTLRDelta375) or 368 (MTLRDelta369), were constructed and C-terminally tagged with an EGFP and stably expressed in CHO cells co-expressing the Ca(2+) indicator apoaequorin. Activity and desensitization were studied by measuring changes in motilin-induced luminescent Ca(2+) rises. Receptor phosphorylation was investigated by immunoprecipitation and MTLR-EGFP internalization was visualized by fluorescence microscopy. Truncation only reduced MTLR affinity and the efficacy to induce Ca(2+) luminescent responses of the MTLRDelta375-EGFP mutant. Furthermore, the region between amino acid 375 and 368 seems to be important for proper cell surface expression of the MTLR since receptors of the MTLRDelta369-EGFP mutant but not of the other mutants were found intracellularly in vesicles. Truncation of the receptor till amino acid 384 or 374 did neither affect desensitization nor internalization. In contrast phosphorylation of the MTLRDelta385-EGFP mutant was reduced by 80% but was not affected in the MTLRDelta375-EGFP mutant. In conclusion, MTLR desensitization and internalization is not dependent on the presence of the C-terminal tail. Truncation favors internalization via either phosphorylation-independent pathways or via phosphorylation of alternative sites in the receptor. 相似文献
188.
Hülya Karaca Gençer Serkan Levent Ulviye Acar Çevik Yusuf Özkay Sinem Ilgın 《Bioorganic & medicinal chemistry letters》2017,27(5):1162-1168
Owing to the growing need for novel antibacterial agents, we synthesized a novel series of fluoroquinolones including 7-substituted-1-(2,4-difluorophenyl)-6-fluoro-4-oxo-1,4-dihydro[1,8]naphthyridine-3-carboxylic acid derivatives, which were tested against clinically relevant Gram positive and Gram negative bacteria. Chemical structures of the synthesized compounds were identified using spectroscopic methods. In vitro antimicrobial effects of the compounds were determined via microdilution assay. Microbiological examination revealed that compounds 13 and 14 possess a good antibacterial profile. Compound 14 was the most active and showed an antibacterial profile comparable to that of the reference drugs trovafloxacin, moxifloxacin, and ciprofloxacin. A significant MIC90 value (1.95 μg/mL) against S. aureus ATCC 25923, E. coli ATCC 35218, and E. coli ATCC 25922 was recorded for compound 14. We observed reduced metabolic activity associated with compounds 13 and 14 in the relevant bacteria via a luminescence ATP assay. Results of this assay supported the antibacterial potency of compounds 13 and 14. An E. coli DNA gyrase inhibitory assay indicated that compound 14 is a potent inhibitor of E. coli DNA gyrase. Docking studies revealed that there is a strong interaction between compound 14 and the E. coli DNA gyrase enzyme. Genotoxicity and cytotoxicity evaluations of compounds 13 and 14 showed that compound 14 is non-genotoxic and less cytotoxic compared to the reference drugs (trovafloxacin, moxifloxacin, and ciprofloxacin), which increases its biological importance. 相似文献
189.
Sharda Pasricha Deepti Sharma Himanshu Ojha Pragya Gahlot Mallika Pathak Mitra Basu Raman Chawla Sugandha Singhal Anju Singh Rajeev Goel Shrikant Kukreti Shefali Shukla 《Luminescence》2017,32(7):1252-1262
Chalcones possess various biological properties, for example, antimicrobial, anti‐inflammatory, analgesic, antimalarial, anticancer, antiprotozoal and antitubercular activity. In this study, naphthylchalcone derivatives were synthesized and characterized using 1H NMR 13C NMR, Fourier transform infrared and mass techniques. Yields for all derivatives were found to be >90%. Protein–drug interactions influence the absorption, distribution, metabolism and excretion (ADME) properties of a drug. Therefore, to establish whether the synthesized naphthylchalcone derivatives can be used as drugs, their binding interaction toward a serum protein (bovine serum albumin) was investigated using fluorescence, circular dichroism and molecular docking techniques under physiological conditions. Fluorescence quenching of the protein in the presence of naphthylchalcone derivatives, and other derived parameters such as association constants, number of binding sites and static quenching involving confirmed non‐covalent binding interactions in the protein–ligand complex were observed. Circular dichroism clearly showed changes in the secondary structure of the protein in the presence of naphthylchalcones, indicating binding between the derivatives and the serum protein. Molecular modelling further confirmed the binding mode of naphthylchalcone derivatives in bovine serum albumin. A site‐specific molecular docking study of naphthylchalcone derivatives with serum albumin showed that binding took place primarily in the aromatic low helix and then in subdomain II. The dominance of hydrophobic, hydrophilic and hydrogen bonding was clearly visible and was responsible for stabilization of the complex. 相似文献
190.
A series of Ce3+‐activated blue‐emitting phosphors BaY2Si3O10 (BYSO) was designed and synthesized by a conventional solid‐state method. Upon ultraviolet light (250–370 nm) excitation, the obtained phosphors showed an intense blue emission band centered at 400–427 nm depending on doping concentration, and corresponding to the 5d→4f transition of Ce3+. The effects of doping concentration on crystal structure, emitting color, photoluminescence and photoluminescence excitation spectra, as well as the concentration quenching mechanism were studied in detail. The optimal doping concentration of Ce3+ in this phosphor was demonstrated to be about 0.75% and the concentration quenching mechanism can be ascribed to electric dipole–dipole interactions with a critical distance of ~38 Å. These fine luminescence properties indicate that BYSO:Ce3+ may be a potential blue phosphor for full‐color ultra‐violet (UV) white light emitting diodes (WLEDs). 相似文献