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81.
Two novel enzyme immunoassays of fentanyl have been developed using Horseradish Peroxidase (HRP) as an enzyme, 3,3′,5,5′tetramethylbenzidine (TMB) and luminol as its colorimetric and its chemiluminescence substrate, respectively. A fentanyl polyclonal antibody was used as a capture antibody for fentanyl and fentanyl-bovine serum albumin (BSA) conjugate. The latter was first biotinylated and then bound by streptavidin labeled with HRP, resulting in the development of two novel competitive immunoassays. The detection limits were 0.045 and 0.0048 ng ml−1 for spectrophotometric and chemiluminescence detection, respectively, and were much lower than existing HRP-fentanyl based kits. Intra- and inter-assay CVs were 2.6-4.5 and 5.4-11.2%, respectively, at concentrations of 0.050-5.000 ng ml−1 for the colorimetric assay, whilst for the chemiluminescent assay intra- and inter-assay CVs were 3.7-6.2 and 6.2-12.3%, respectively, for the linear range of the assay at concentrations of 0.008-0.800 ng ml−1. The methods in this study were developed in order to measure maternal and neonatal fentanyl plasma samples during cesarean section, after the application of a novel subarachnoid analgesia technique. The 28 maternal and neonatal plasma samples were measured by both assays, providing data for subarachnoid administration of fentanyl that had never been presented before. 相似文献
82.
Fokialakis N Magiatis P Chinou I Mitaku S Tillequin F 《Chemical & pharmaceutical bulletin》2002,50(3):413-414
Two alkaloids, megistoquinone I (1) and megistoquinone II (2), were isolated from the bark of Sarcomelicope megistophylla. Their structures have been elucidated on the basis of MS and NMR data. Both belong to quinoline alkaloid series and should be considered as oxidation products of a furo[2,3-b]quinoline precursor. The two alkaloids showed antibacterial properties with minimum inhibitory concentration (MIC) ranging from 2.35 to 5.25 mg/ml for 1 and 0.73 to 1.23 mg/ml for 2. 相似文献
83.
Nikos G. Tsierkezos Ioanna E. Molinou Alexander C. Filippou 《Journal of solution chemistry》2005,34(12):1371-1386
The excess molar volumes (VE), excess surface tensions (σE), and deviations in molar refraction (RE) and isentropic compressibility (ksE) of binary mixtures of cyclohexanone with methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol have been determined over
the entire composition range at 293.15 K. The results were fitted by the Redlich–Kister polynomial equation and the corresponding
binary coefficients Ak have been derived. The standard deviations between the calculated and the experimental excess properties have been determined.
The results provide information on the interactions of the molecules in the pure liquids as well as in the binary mixtures. 相似文献
84.
Tsierkezos NG Roithova J Schröder D Molinou IE Schwarz H 《The journal of physical chemistry. B》2008,112(14):4365-4371
The solvation of copper(II) sulfate in binary mixtures of water and N,N-dimethylformamide (DMF) is studied by a combined approach using electrochemical studies in solution and a mass spectrometric assay of the solvated ions formed from these solutions upon electrospray ionization (ESI). In the condensed phase, the limiting transference numbers (t(+/-)(o)) and the apparent ion association constants (K(A)'s) of CuSO(4) have been determined in water/DMF solutions at 20 degrees C. The t(+)(o) values decrease with increasing DMF content, demonstrating a gradual solvation of Cu(2+) by DMF molecules. The association constants indicate that aggregation becomes more pronounced as the DMF content increases. In order to achieve complementary insight, the intrinsic interactions among the ions and solvent molecules are investigated in gas-phase experiments of the CuSO(4)/water/DMF system using ESI mass spectrometry. Under the conditions used, the dications [Cu(DMF)(n)](2+) (n = 3-6), [Cu(2)(DMF)(n)SO(4)](2+) (n = 2-7), and [Cu(3)(DMF)(n)(SO(4))(2)](2+) (n = 2-7), and the monocations [Cu(OH)(DMF)(n)](+), [Cu(DMF)(n)(HSO(4))](+) (both, n = 1-3), and [Cu(DMF)(n)](+) (n = 1, 2), are formed as the leading copper-containing cations. Likewise, polynuclear copper clusters observed in the anion ESI spectra support partial aggregation occurring in solution. The gas-phase studies clearly support the conclusions that (i) DMF is a highly preferred ligand for CuII in comparison to water and that (ii) DMF supports ion association for which the mass spectrometric data suggest the formation of polynuclear copper clusters. 相似文献
85.
Detailed studies on the kinetics and the thermodynamics of the excited-state torsional isomerization of the title molecule (1) relative to exocyclic C2-O bond, when dissolved in 3-methylpentane, are reported by means of nontime- and time-resolved fluorescence spectroscopy. Over the broad temperature range studied, 1 exists in spectrally distinct, thermally equilibrated s-cis and s-trans conformations in the ground state (S(0)). In the lowest excited singlet state (S(1)) and above 260 K a pure adiabatic interconversion channel is activated that interconverts s-cis* and s-trans* conformers through a nearly fully reversible isomerization pathway with an activation energy of about 29 kJ/mol. The excited-state equilibrium constant is found to be remarkably temperature-independent just barely exceeding 1 above 260 K. Contrary to the predominantly irreversible photoisomerization mechanism generally observed in related compounds, this work provides insights into the high reversibility of an excited-state rotameric equilibration in solution. 相似文献
86.
The antioxidant and antimicrobial activity of methanol or dichloromethane extracts of O. dictamnus, produced from wild and organic cultivated specimens, were determined. The Rancimat and malondialdehyde (MDA) by HPLC methods were used to measure the antioxidant action, in comparison with that of the common commercial antioxidants butylated hydroxytoluene (BHT) and alpha-tocopherol. The extracts that presented high antioxidant activity were encapsulated in liposomes and their antioxidant action was again estimated using differential scanning calorimetry (DSC). Thermaloxidative decomposition of the samples (pure liposomes and encapsulated extracts) and the modification of the main transition temperature for the lipid mixture and the splitting of the calorimetric peak in the presence of the antioxidants were also studied by the DSC method. All extracts showed antioxidant and antimicrobial activities. Their action proved superior to alpha-tocopherol. The methanol extract of organic cultivated O. dictamnus (240 ppm) showed higher activity than butylated hydroxytoluene. After encapsulation in liposomes the antioxidant as well as antimicrobial activities proved to be higher than those of the same extracts in pure form. 相似文献
87.
The complexity and dynamics of chaotic attractors generated in an InGaAsP-InP microring laser are calculated and evaluated by using a multimode rate equation model. Chaos originates from the continuous mutual injections from each mode to the other because of the bus waveguide's residual reflectivity at high values of the injection current. The data analysis of the filtered output power reveals high-dimensional chaos, and phase-dependent behavior is demonstrated. 相似文献
88.
Dimitroula Tsiri Nektarios Aligiannis Konstantia Graikou Caroline Spyropoulos Ioanna Chinou 《Helvetica chimica acta》2008,91(11):2110-2114
A chemical study on tissue cultures from leaves and flowers of E. camaldulensis Dehnh . afforded the new natural product (2α,3β)‐2,3,23‐trihydroxy‐13,28‐epoxyurs‐11‐en‐28‐one (dryobalanolide) together with the known pentacyclic triterpenoids: betulinic acid, oleanolic acid, ursolic acid, (2α,3β)‐2,3,23‐trihydroxyolean‐12‐en‐28‐oic acid (arjunolic acid), (2α,3β)‐2,3,23‐trihydroxyurs‐12‐en‐28‐oic acid (asiatic acid), (2α)‐2‐hydroxyursolic acid, (2α)‐2‐hydroxyoleanolic acid (maslinic acid), as well as β‐sitosterol. The extracts and the isolated compounds were evaluated against eleven human pathogenic microorganisms, exhibiting a very interesting antibacterial spectrum of activities. 相似文献
89.
Four new metabolites (1-4) have been isolated from the organic extract of the seagrass Cymodocea nodosa, collected at the coastal area of Porto Germeno, in Attica Greece. Compounds 1 and 2 belong to the structural class of diarylheptanoids, which have been found only once before in marine organisms [Kontiza, I.; Vagias, C.; Jakupovic, J.; Moreau, D.; Roussakis, C.; Roussis, V. Tetrahedron Lett.2005, 46, 2845-2847]. Compound 3 is a new meroterpenoid, while compound 4, to the best of our knowledge, is the first briarane diterpene isolated from seaweeds, and only the second analog of this class with a tricyclic skeleton. Furthermore metabolite 4 is the first brominated briarane diterpene. The structures and the relative stereochemistry of the new natural products were established by spectral data analyses. The new metabolites were submitted for evaluation of their antibacterial activity against multidrug-resistant (MDR) pathogens including methicillin-resistant (MRSA) strains of Staphylococcus aureus, as well as the rapidly growing mycobacteria, Mycobacterium phlei, Mycobacterium smegmatis, and Mycobacterium fortuitum. 相似文献
90.