Search results for "Chlorin"
showing 10 items of 374 documents
Interactions of benzodiazepines with human serum albumin. Circular dichroism studies.
1973
The circular dichroism spectra of 12 benzodiazepine derivatives studied in presence of human serum albumin are presented. Nearly all substances give biphasic extrinsic Cotton effects. At the CD maxima the molar ellipticities and the anisotropy factors are calculated. The influence of the chemical structure of the benzodiazepines on the induced Cotton effect is discussed. There is a linear correlation between the anisotropy factors and the logarithms of the partition coefficients of the substances. It is suggested that the phenyl ring of the benzodiazepine molecule is one of the essential groups for the binding of these substances to human serum albumin.
Comparison of Methods and Kits for Colorimetric Determination of Residual Chlorine in Water
1997
Abstract The use of 3,3',5,5'-tetramethylbenzidine (TMB) for residual chlorine determination in water offers 2 possibilities, one at pH 1-2 and absorbance measurement at 450 nm and another at pH 3.8-5.8 and measurement at 650 nm. The reaction of chlorine with TMB reaches its maximum sensitivity at pH 1-2. The detection limit is 2 ng/mL. A calibrated scale for colorimetric determination of residual chlorine in water with 3,3',5,5'-tetramethylbenzidine (TMB), prepared with tropaeolin O (C.I. 14270), is described. This scale is stable for several months and can be useful in replacing the conventional and much less stable scale prepared from standard solutions of oxochlorate (I). Kits for deter…
A two-circuit apparatus for the perfusion of the isolated rat brain.
1973
A perfusion apparatus for the isolated rat brain is described which has two recirculating systems running synchronously. Instantaneous transfer from one circulating system to the other is possible by use of a 2-way stopcock, enabling different media to be perfused through the brain without interrupting the perfusion. The feasibility of the system is demonstrated experimentally.
Horseradish peroxidase-catalyzed oxidation of chlorophyll a with hydrogen peroxide
2010
Horseradish peroxidase was verified to catalyze, without any phenol, the hydrogen peroxide oxidation of chlorophyll a (Chl a), solubilized with Triton X-100. The 13(2)(S) and 13(2)(R) diastereomers of 13(2)-hydroxyChl a were characterized as major oxidation products (ca. 60%) by TLC on sucrose, UV-vis, (1)H, and (13)C NMR spectra, as well as fast-atom bombardment MS. A minor amount of the 15(2)-methyl, 17(3)-phytyl ester of Mg-unstable chlorin was identified on the basis of its UV-vis spectrum and reactivity with diazomethane, which converted it to the 13(1),15(2)-dimethyl, 17(3)-phytyl ester of Mg-purpurin 7. The side products (ca. 10%) were suggested to include the 17(3)-phytyl ester of M…
Penning-trap mass measurements of neutron-deficient Rb and Sr isotopes
1993
Abstract The Penning-trap mass spectrometer ISOLTRAP installed at the on-line mass separator ISOLDE 2 at CERN has been used for mass determination of 75–87 Rb and 78–83,87 Sr. Ions are captured in a Penning trap and their cyclotron frequency ω c = ( q m )B in the trapping field B is measured. Ratios of these frequencies lead to the determination of the atomic mass of these isotopes. A resolving power of typically m Δm = 10 6 and an accuracy of δm ≈10 keV is obtained. The mass of 78 Sr is measured for the first time and, in most cases, the mass values of the other isotopes are significantly improved. The experimental masses are compared with theoretical predictions.
N-Alkyl Ammonium Resorcinarene Salts as High-Affinity Tetravalent Chloride Receptors.
2016
N-Alkyl ammonium resorcinarene salts (NARYs, Y=triflate, picrate, nitrate, trifluoroacetates and NARBr) as tetravalent receptors, are shown to have a strong affinity for chlorides. The high affinity for chlorides was confirmed from a multitude of exchange experiments in solution (NMR and UV/Vis), gas phase (mass spectrometry), and solid-state (X-ray crystallography). A new tetra-iodide resorcinarene salt (NARI) was isolated and fully characterized from exchange experiments in the solid-state. Competition experiments with a known monovalent bis-urea receptor (5) with strong affinity for chloride, reveals these receptors to have a much higher affinity for the first two chlorides, a similar af…
Gas—liquid chromatographic analyses
1989
Abstract The retention (I), dispersion (IM) and selectivity (I*) indices of sixteen polychlorinated dibenzo-p-dioxins and fourteen polychlorinated dibenzofurans were determined on a low-polarity HP-5 capillary column using a gas chromatograph connected with an ion-selective detector. IM and I* values were also calculated for all 73 dibenzo-p-dioxins from the di- to the octachloro isomer and for all possible 135 chlorinated dibenzofurans based on the predicted retention index data reported earlier. The effect of the position of chlorination is shown and the results are compared with those for several series of chlorinated aromatics.
Electrochemical production and use of chlorinated oxidants for the treatment of wastewater contaminated by organic pollutants and disinfection
2021
Abstract In the last years, an increasing attention has been devoted to the use of electrogenerated chlorinated oxidants for the treatment of wastewater polluted by recalcitrant organics and/or for the disinfection of water contaminated by pathogen microorganisms. In this review, more recent and relevant findings were presented and critically discussed. The main advantages and disadvantages of this technique were commented, including the potential formation of toxic chlorinated organic specie and of chlorate and perchlorate or the difficult selection of proper operative parameters, as well as the key points that should be addressed to enhance the use on an applicative scale.
Environmentally Relevant Properties of All 209 Polychlorinated Biphenyl Congeners for Modeling Their Fate in Different Natural and Climatic Conditions
2009
The temperature dependence of physical properties and degradation lifetimes in the environment of all polychlorinated biphenyl (PCB) congeners (N = 209) were determined. For physical properties, the coefficients A and B in equations log(property) = A(property) − B(property)/T(K) were determined by thermodynamic and QSPR methods and compared with the results of independent methods in the literature. The coefficients Apl and Bpl for liquid state vapor pressure PL, As and Bs for solubility in water SW, Ah and Bh for volatility kH (or kH = PL/SW), and Aow and Bow for lipophilicity (KOW), stored in the database of the fate model program, allowed automatic temperature corrections for realistic fa…
Single and Coupled Electrochemical Processes and Reactors for the Abatement of Organic Water Pollutants: A Critical Review.
2015
Traditional physicochemical and biological techniques, as well as advanced oxidation processes (AOPs), are often inadequate, ineffective, or expensive for industrial water reclamation. Within this context, the electrochemical technologies have found a niche where they can become dominant in the near future, especially for the abatement of biorefractory substances. In this critical review, some of the most promising electrochemical tools for the treatment of wastewater contaminated by organic pollutants are discussed in detail with the following goals: (1) to present the fundamental aspects of the selected processes; (2) to discuss the effect of both the main operating parameters and the rea…