Radio Frequency Interference /RFI/ design guide for aerospace communications systems

Radio frequency interference design guide for aerospace communications system

Episodic Tourette's syndrome in a patient with citrullinemia

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50316/1/410190625_ftp.pd

Separation of urinary catecholamines and catecholamine metabolites by high-pressure liquid chromatography

A series of high-pressure liquid chromatographic (hplc) procedures are described for the separation of all major and most minor catecholamine metabolites present in human urine. The amines and metabolites are first concentrated and partially purified by traditional methods, ion-exchange and alumina chromatography. Final separations are then performed with hplc. Our system is specifically designed to study dopamine [beta]-hydroxylation in vivo. [3H]Dopamine is administered intravenously to human subjects, and then all the excreted [3H]dopamine metabolites and [3H]norepinephrine metabolites are separated and assayed. The high degree of resolution achieved with hplc makes it possible to separate the small population of [3H]norepinephrine metabolites from the much larger population of [3H]-dopamine metabolites. The ratio of total excreted [3H]norepinephrine metabolites/total excreted [3H]dopamine metabolites averages 0.029 +/- 0.005 in urine samples collected during the first 6 h following the administration of isotope.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23227/1/0000160.pd

Hetero-association of aromatic molecules in aqueous solution

Knowledge of the physical chemistry of small molecules complexation (the hetero-association) in aqueous solution is increasingly important in view of the rapidly emerging branch of supramolecular chemistry dealing with the formation of heterogeneous polymeric structures having specific functional roles. In this paper, the 50-year history of scientific studies of hetero-association of heterocyclic aromatic molecules in aqueous solution has been reviewed. Some important correlations of structural and thermodynamic parameters of complexation have been reported based on large data-set of hetero-association parameters accumulated to date. The fundamental problem of ‘energetic composition’ of π-stacking is extensively discussed. The review has shown that there are some gaps in our understanding of heteroassociation, which provides a challenge for further studies in this are

Role of Glutathione Redox State in Oxygen Sensing by Carotid Body Chemoreceptor Cells

Producción CientíficaThis article first presents some basic structural traits of the carotid body (CB) arterial chemoreceptors to understand the relationship between the arterial blood PO2 and the activation of chemoreceptor cells, which are the O2 sensing structures of the CB. Some considerations in relation to the intensity of CB blood flow and O2 consumption of the organ would allow us to define the threshold for the detection of the hypoxic stimulus, which would lead us to the cardinal theme of the article, namely whether at the PO2 levels detected by the CB there alterations in the genesis of re-active oxygen species (ROS). An alteration in the rate of ROS productionwould impinge on the glutathione system [reduced glutathione (GSH) and oxidized glutathione (GSSG)], causing modifications in the GSH/GSSG ratio that are detected by direct measurement; the GSH/GSSG system rep-resents the quantitatively most important mechanism to dispose ROS and to maintain the overall redox status or redox environment in mammalian cells.1 The relationship between GSH/GSSG and oxygen chemoreception is approached from two different points of view. We will measure GSH/GSSG levels and calculate the redox environment of the cells and correl-ation with the activity of chemoreceptor cells in normoxia and in hypoxia. We will also present data on pharmacological manipulation of the redox environment of the cells, as assessed by GSH/GSSG quotients, and pos-sible correlations with the level of activity of chemoreceptor cells. The possible mechanisms of coupling between ROS and the GSH/GSSG system to the cellular effector machineries have been reviewed.2,