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Luminescence: the Journal of Biological and Chemical Luminescence

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https://www.readbyqxmd.com/read/29770991/probing-the-interaction-of-l-captopril-with-metallo-%C3%AE-lactamase-ccra-by-fluorescence-spectra-and-molecular-dynamic-simulation
#1
Penghui Shi, Yan Zhang, Yuhua Li, Liujiao Bian
Both the molecular recognition and interaction of metallo-β-lactamase CcrA with l-captopril were studied by the combined use of fluorescence spectra and molecular dynamic simulation. The results showed that the binding constant was 8.89 × 104  L mol-1 at 296 K. Both Zn1 and Zn2 displayed tetrahedral coordination geometries in the CcrA-Lcap complex, the S atom in l-captopril displaced the nucleophilic hydroxide in apo CcrA and occupied the fourth coordination site for each ion, resulting in a competitively inhibited CcrA enzyme...
May 17, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29745063/effect-of-viscosity-and-dielectric-constant-variation-on-fractional-fluorescence-quenching-analysis-of-coumarin-dye-in-binary-solvent-mixtures
#2
P Bhavya, Raveendra Melavanki, Raviraj Kusanur, Kalpana Sharma, V T Muttannavar, L R Naik
Photo physical properties of fluorescent organic compounds give an immense improved knowledge on characteristics of excited state that is beneficial to devise innovate molecules and understand their performance in particular applications. Coumarin derivatives have been extensively investigated in this regard. This article narrates steady state fluorescence quenching measurements of a coumarin derivative namely 3-hydroxy-3-[2-oxo-2-(3-oxo-3H-benzo[f]chromen-2-yl)-ethyl]-1,3-dihydro-indol-2-one (3HBCD) in a binary mixture of acetonitrile and 1,4-dioxane...
May 10, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29745015/trivalent-rare-earth-activated-hexagonal-lanthanum-fluoride-laf-3-re-3-where-re-tb-sm-dy-and-tm-nanocrystals-synthesis-and-optical-properties
#3
Singh Kasturi, R Marikumar, Sivakumar Vaidyanathan
The LaF3 nanocrystals through a facile hydrothermal route with hexagonal structures have been synthesized via doping of trivalent rare earth (RE3+ ) ions - RE = Tb, Sm, Dy and Tm - with rod-like and perforated morphologies using NH4 F as fluorine precursor. Hexagonal phase formation was confirmed by powder X-ray diffraction. The crystalline sizes were calculated by the Scherrer equation where found to have an average crystalline size of 12 to 35 nm. The morphological studies of the nanocrystals were carried out by means of transmission electron microscopy (TEM)...
May 10, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29737023/liquid-chromatographic-and-spectrofluorimetric-assays-of-empagliflozin-applied-to-degradation-kinetic-study-and-content-uniformity-testing
#4
Maha F Abdel-Ghany, Miriam F Ayad, Mariam M Tadros
Stability-indicating high-performance liquid chromatography (HPLC) and spectrofluorimetric methods were developed for determination of empagliflozin (EGF). EGF was subjected to oxidation, wet heat, photo-degradation, acid hydrolysis and alkali hydrolysis. The alkaline degradation pathway was subjected to a kinetics study as the major product obtained after stress conditions. Arrhenius plots were constructed and the activation energies of the degradation process were calculated. HPLC was used for the kinetic study as it enabled simultaneous determination of EGF and the degradation product while the spectrofluorimetric assay was applied to content uniformity testing due to its higher sensitivity and lower limit of detection (LOD)...
May 7, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29708642/enhancing-the-chemiluminescence-intensity-of-a-kmno-4-formaldehyde-system-for-estimating-the-total-phenolic-content-in-honey-samples-using-a-novel-nanodroplet-mixing-approach-in-a-microfluidics-platform
#5
Haider A J Al Lawati, Baqia Al Mughairy, Iman Al Lawati, FakhrEldin O Suliman
A novel mixing approach was utilized with a highly sensitive chemiluminescence (CL) method to determine the total phenolic content (TPC) in honey samples using an acidic potassium permanganate-formaldehyde system. The mixing approach was based on exploiting the mixing efficiency of nanodroplets generated in a microfluidic platform. Careful optimization of the instrument setup and various experimental conditions were employed to obtain excellent sensitivity. The mixing efficiency of the droplets was compared with the CL signal intensity obtained using the common serpentine chip design, with both approaches using at a total flow rate of 15 μl min-1 ; the results showed that the nanodroplets provided 600% higher CL signal intensity at this low flow rate...
April 30, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29708303/utility-of-von-pechman-synthesis-of-coumarin-reaction-for-development-of-spectrofluorimetric-method-for-quantitation-of-salmeterol-xinafoate-in-pharmaceutical-preparations-and-human-plasma
#6
Mohamed Awad, Mohamed A Hammad, Ahmed M Abdel-Megied, Mahmoud A Omar
Simple, precise and selective spectrofluorimetric technique was evolved for quantitation of selective β2 agonist drug namely salmeterol xinafoate (SAL). Utilizing its phenolic nature, a method was described based on the reaction of the studied drug with ethyl acetoacetate (EAA) to yield extremely fluorescent coumarin product which can be detected at 480 nm (λex  = 420 nm). The procedure obeys Beer's law with a correlation coefficient of r = 0.9999 in the concentration range between 500 and 5000 ng ml-1 with and 177 ng ml-1 for limit of detection (LOD) and limit of quantification (LOQ), respectively...
April 30, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29708301/enhanced-chemiluminescence-of-the-fluorescein-kio-4-system-by-cdte-quantum-dots-for-determination-of-catechol
#7
Na Cai, DongQin Yang, YanYan He, FuNan Chen
In this paper, a novel chemiluminescence (CL) system was introduced based on the use of CdTe quantum dots (QDs) with the mixture solutions of fluorescein and potassium periodate (KIO4 ) in alkaline medium. The CL signal of an ultra-weak system was strongly enhanced in the presence of QDs. The application of CdTe QDs-fluorescein-KIO4 system is reported for the first time. It was found that catechol had a diminishing effect on the CL reaction. Under optimal experimental conditions, CL intensity decreased linearly in a 1 to 100 μM catechol concentration range, with a 0...
April 30, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29687589/fluorimetric-determination-of-febuxostat-in-dosage-forms-and-in-real-human-plasma-via-f%C3%A3-rster-resonance-energy-transfer
#8
Samia M El-Gizawy, Noha N Atia, Noha M Hosny
A rapid, simple, selective and precise fluorimetric method was developed and validated for determination of a selective xanthine oxidase inhibitor; febuxostat (FBX) in pharmaceutical formulations and in human plasma. The proposed method is based on quenching effect of FBX on the fluorescence intensity of terbium (Tb3+ ) through fluorescence resonance energy transfer (FRET) from Tb3+ to FBX. The formed complex was measured at λex. 320 nm/λem. 490 nm against a reagent blank. Fluorescence intensity of Tb3+ was diminished when FBX was added...
April 24, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29687582/effect-of-annealing-temperature-and-dopant-concentration-on-the-thermoluminescence-sensitivity-in-lif-mg-cu-ag-material
#9
Akram Yahyaabadi, Falamarz Torkzadeh, Dariush Rezaei Ochbelagh, Seyed Mahdi Hosseini Pooya
LiF:Mg,Cu,Ag is a new dosimetry material that is similar to LiF:Mg,Cu,P in terms of dosimetric properties. The effect of the annealing temperature in the range of 200 to 350°C on the thermoluminescence (TL) sensitivity and the glow curve structure of this material at different concentrations of silver (Ag) was investigated. It has been demonstrated that the optimum values of the annealing temperature and the Ag concentration are 240°C and 0.1 mol% for better sensitivity, respectively. The TL intensity decreases at annealing temperatures lower than 240°C or higher than 240°C, reaching a minimum at 300°C and then again increases for various Ag concentrations...
April 24, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29687571/the-size-effect-to-o-2-ce-4-charge-transfer-emission-and-band-gap-structure-of-sr-2-ceo-4
#10
Wenjun Wang, Yu Pan, Wenying Zhang, Xiaoguang Liu, Ling Li
Sr2 CeO4 phosphors with different crystalline sizes were synthesized by the sol-gel method or the solid-state reaction. Their crystalline size, luminescence intensity of O2- -Ce4+ charge transfer and energy gaps were obtained through the characterization by X-ray diffraction, photoluminescence spectra, as well as UV-visible diffuse reflectance measurements. An inverse relationship between photoluminescence (PL) spectra and crystalline size was observed when the heating temperature was from 1000°C to 1300°C...
April 24, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29687574/can-earthworms-biosynthesize-highly-luminescent-quantum-dots
#11
Farzane Talaeeshoar, Hamid Delavari H, Reza Poursalehi
Band gap tunable cadmium selenide (CdSe) quantum dots (QDs) were synthesized within earthworms that emit in the middle of the visible spectrum. We demonstrated that this luminescence emission is a combination of the earthworm's protein and QD luminescence, such that the contribution of QDs in the luminescence was negligible. Eisenia fetida earthworms were used for QD biosynthesis and were exposed to different concentrations of CdCl2 and Na2 SeO3 in standard soil for an adequate exposure time. The size of the CdSe QDs based on the effective mass model was in agreement with the size measured from the transmission electron microscopy analysis, with an average diameter of 7 nm...
April 23, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29683250/luminescence-of-eu-3-ions-in-hybrid-polymer-inorganic-composites-based-on-poly-methyl-methacrylate-and-zirconia-nanoparticles
#12
Alexander N Bugrov, Anastasia Yu Zavialova, Ruslan Yu Smyslov, Tatyana D Anan'eva, Elena N Vlasova, Maxim V Mokeev, Artem E Kryukov, Gennady P Kopitsa, Vitaliy Pipich
Spherical nanoparticles of ZrO2 with 2 and 10 mol% EuO1.5 up to 20 nm size were prepared by the method of hydrothermal synthesis for luminescent functionalization of the polymer-inorganic nanocomposites based on poly(methyl methacrylate). Surface modification of oxide nanoparticles was carried out by 3-(trimethoxysilyl)propyl methacrylate, dimethoxymethylvinyl silane and 2-hydroxyethyl methacrylate to provide uniform distribution and to prevent agglomeration of nanosized filler in the polymer matrix. Polymer-inorganic composites were synthesized by in situ free radical polymerization in bulk...
April 23, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29665234/synthesis-and-luminescence-properties-of-novel-8-hydroxyquinoline-derivatives-and-their-eu-iii-complexes
#13
Yongqiang Wu, Tiantong Guo, Dehua Shu, Wu Zhang, Fangfei Luan, Ling Shi, Dongcai Guo
Six novel 8-hydroxyquinoline derivatives were synthesized using 2-methyl-8-hydroxyquinoline and para-substituted phenol as the main starting materials, and were characterized by 1 H nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV) light analysis and infra-red (IR) light analysis. Their complexes with Eu(III) were also prepared and characterized by elemental analysis, molar conductivity, UV light analysis, IR light analysis, and thermogravimetric-differential thermal analysis (TG-DTA)...
April 17, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29653023/%C3%AE-aminobutyric-acid-quantification-in-small-volume-biological-samples-through-enzymatically-induced-electrochemiluminescence
#14
Juan Carlos Salazar-Sánchez, Alberto Morales-Villagrán, Silvia Josefina López-Pérez, Kenia Pardo-Peña, Fridha Villalpando-Vargas, Laura Medina-Ceja
γ-Aminobutyric acid (GABA) is a well-known neurotransmitter that regulates inhibitory neurotransmission in the mammalian central nervous system and participates in several processes outside the brain. A reliable quantification method is needed to determine its role in different physiological and pathological conditions. However, GABA measurements have several challenges because GABA is neither fluorescent nor electroactive, and it is difficult to detect using enzymatic reactions because no oxidases or dehydrogenases have been identified...
April 13, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29644790/using-chemiluminescence-to-determine-whole-blood-antioxidant-capacity-in-rheumatoid-arthritis-and-parkinson-s-disease-patients
#15
Diane L Hughes, Ross S Richards, Louise A Lexis
The consequences of oxidative stress and inflammation are implicated in a wide range of diseases, including rheumatoid arthritis and Parkinson's disease. The status of antioxidant capacity in rheumatoid arthritis and Parkinson's disease remains unclear, in part due to common practice of assaying erythrocytes separately to plasma. This method removes any synergistic interactions between plasma and erythrocyte-based antioxidants. The experiments in this report tested antioxidant capacity in whole blood, erythrocytes and plasma by group and disease stage...
April 11, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29637695/spectrofluorimetric-determination-of-acotiamide-hydrochloride-trihydrate-in-the-presence-of-its-oxidative-degradation-product
#16
Khalid A M Attia, Mohammed W I Nassar, Ahmed El-Olemy, Sherif Ramzy
Acotiamide hydrochloride trihydrate is a novel gastroprokinetic drug which has been recently approved for the treatment of patients with functional dyspepsia. This study presents the first reported to investigate the fluorimetric behavior of acotiamide hydrochloride trihydrate in the presence of its oxidative degradation product. All variables that affect fluorescence intensity were studied and optimized. The described method involved the measurement of native fluorescence of the drug in ethanol at 404 nm after excitation at 326 nm...
April 10, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29637691/aggregation-induced-emission-enhancement-of-anthracene-derived-schiff-base-compounds-and-their-application-as-a-sensor-for-bovine-serum-albumin-and-optical-cell-imaging
#17
Simon Densil, Chien-Huei Chang, Chia-Ling Chen, Alagarsamy Mathavan, Arumugam Ramdass, Veerasamy Sathish, Pounraj Thanasekaran, Wen-Shan Li, Seenivasan Rajagopal
Three anthracene-based Schiff base complexes, R1-R3 (R1 = (E)-N´-((anthracen-10-yl)methylene)benzohydrazide; R2 = (E)-1-((anthracen-10-yl)methylene)-4-phenylsemicarbazide; and R3 = (E)-1-((anthracen-10-yl)methylene)-4-phenylthiosemicarbazide) were synthesized from 9-anthracenecarboxaldehyde, benzohydrazide, 4-phenylsemicarbazide and 4-phenylthiosemi-carbazide respectively, and characterized by various spectral techniques. The absorption spectral characteristics of R1-R3 were bathochromically tuned to the visible region by extending the π conjugation...
April 10, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29637685/characteristic-features-of-thermoluminescence-in-neodymium-doped-gallium-sulfide
#18
I Guler, M Isik, F Ahmedova, A Guseinov, N Gasanly
The thermoluminescence (TL) of neodymium-doped gallium sulfide (GaS:Nd) single crystals was measured from 10 K to room temperature with various heating rates between 0.2 and 1.0 K/sec. Two peaks centered at 70.9 K and 116.0 K were observed when using a heating rate of 0.8 K/sec. Initial rise and curve fitting methods were used to obtain information on trap activation energies. Activation energies of 94 and 216 meV were found for two analyzable peaks. The heating rate dependencies of TL intensities revealed that one of the observed peaks showed normal behavior according to the one trap-one recombination model, whereas the other model showed anomalous heating rate behavior...
April 10, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29607616/a-real-time-fluorescence-assay-for-protease-activity-and-inhibitor-screening-based-on-the-aggregation-caused-quenching-of-a-perylene-probe
#19
Yan Wang, Zhifang Zhang, Ya Zhang, Cong Yu
We have established a real-time and label-free fluorescence turn-on strategy for protease activity detection and inhibitor screening via peptide-induced aggregation-caused quenching of a perylene probe. Because of electrostatic interactions and high hydrophilicity, poly-l-glutamic acid sodium salt (PGA; a negatively charged peptide) could induce aggregation of a positively charged perylene probe (probe 1) and the monomer fluorescence of probe 1 was effectively quenched. After a protease was added, PGA was enzymatically hydrolyzed into small fragments and probe 1 disaggregated...
April 1, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/29605968/sensitive-determination-of-bromhexine-hydrochloride-based-on-its-quenching-effect-on-luminol-h-2-o-2-electrochemiluminescence-system
#20
Dexian Kong, Siqin Huang, Jiansong Cheng, Qizhao Zhuang, Yijun Liu, Chun-Hua Lu
In this paper, the electrochemiluminescence (ECL) behavior of luminol/H2 O2 system in the presence of bromhexine hydrochloride (BrH) was investigated. It was found that the ECL intensity of luminol/H2 O2 system on a platinum electrode could be intensely quenched by BrH owing to the scavenging superoxide radical ability of BrH, and therefore the sensitive determination of BrH was possible. Under optimal conditions, the quenched ECL intensity was linear to the concentration of BrH in a wide range of 0.08 to 500 μM, with a detection limit of 0...
April 1, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
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