Manganese ions probes

Manganese ions enzyme activators, 6,578 probes, 6,563 RNA polymerases activation, 6, 585 transport microbes, 6, 569 plants, 6, 572 Manganese oxide colloidal... 

The permeation and clearance of model ionic permeants after subconjunctival injection was assessed with NMR imaging. New Zealand white rabbit was the animal model and manganese ion (Mn ) and manganese EDTA complex (MnEDTA ) were the model permeants. The current study was divided into three parts in vitro, postmortem, and in vivo. Transscleral passive permeation experiments were conducted with excised sclera in side-by-side diffusion cells in vitro. Sub-conjunctival delivery experiments were conducted with rabbits postmortem and in vivo. The distribution and elimination of the probe permeants from the subconjunctival space after subconjunctival injections were determined by MRI. The permeability coefficients of Mn and MnEDTA across the sclera in vitro were 3.6 x 10 cm/s and 2.4 x 10 cm/s, respectively. 

Heterocyclic nitrogen donors and their adducts with zinc chloride have been studied.623,624 A large number of other ligand systems have also been characterized, for example, zinc halide adducts of 2,2-dimethylpropane-1,3-diamine and hexamethylphosphoramide have been studied.625,626 The formation of mixed ligand complexes with chloride and substituted pyridines has been studied.627 The zinc tris(pyridyl) chloride anion has also been structurally characterized.628 Manganese(II) ions have been used to probe the stereochemistry in reactions of zinc halides with pyrazine.629... 

The few vanadium-based studies present in the literature are summarized briefly here and, as with the manganese systems, they focus on the identification of key Intermediates in vanadium-catalyzed oxidations. These cases readily Illustrate the importance of considering both the positive and negative ion modes of ESl-MS when probing reaction mixtures. 

The third principal application of the electron spin resonance technique is to the study of paramagnetic transition metal ions in biochemical systems. Most examples are complexes of copper, iron, manganese, chromium, cobalt and molybdenum. Other metals such as titanium, vanadium and nickel are sometimes employed as structural probes. Only four of these ions, Cu ", Mn, Gd " and VO ", are seen in ESR spectroscopy at room temperature under virtually all conditions. Therefore, they are of special importance. 

Feig AL (2000) The use of manganese as a probe for elucidating the role of magnesium ions in ribozymes. Met Ions Biol Syst 37 157-182... 

The Use of Manganese as a Probe for Elucidating the Role of Magnesium Ions in Ribozymes... 

The use of thallium-205 as a probe for potassium has been suggested, - and Kayne and Reuben have used the broadening between the signals of the two paramagnetic ions thallium(i) and manganese(n) to estimate the distance between the monovalent and bivalent activators in rabbit muscle pyruvate kinase. Several cases of the inhibition of Ca + transport processes by lanthanides have been reported, and Williams and co-workers have proposed the use of the lanthanides as probes for calcium. 

The main experimental use of barium is in electrophysiology where it can be used as a charged probe for metal ion-dependent processes. The isolation and identification of individual ion fluxes which contribute to the electric currents flowing through cell membranes often requires techniques to block specific components of electrical activity. This can sometimes be achieved by the use of the soluble salts of divalent cations such as barium and manganese which may block potassium and calcium and currents in, for example, the cardiac pacemaker [4]. Barium can also be used to identify potassium-conducting channels in isolated membrane vesicles [S,6] or calcium charmels in isolated heart muscle cells, myocytes [7], and adrenal gland chromaffin cells [8]. 

McNeill 11,12) has established that the initial step when a transition metal halide is combined with PMMA is coordination of the metal ion to the carbonyl oxygens of the polymer. This is usually followed by the loss of methyl halide and the formation of a metal polymethacrylate. TGA/IR has provided interesting means to probe these systems to compare results using manganese chloride IS) and chromium (111) diloride 19) as PMMA additives. Weight loss data and identification of the evolved gases for both additives are rqwrted below in Table 1. 

Volume 37 Manganese and Its Role in Biological Processes Volume 38 Probing of Proteins by Metal Ions and Their Low-Molecular-Weight Complexes... 

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