Clinical and Laboratory Studies with Selective Monoamine-Oxidase-Inhibiting Drugs

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

International Astronomical Union Colloquium ◽

10.1017/s025292110001469x ◽

1997 ◽

Vol 161 ◽

pp. 179-187

Author(s):

Clifford N. Matthews ◽

Rose A. Pesce-Rodriguez ◽

Shirley A. Liebman

Keyword(s):

Amino Acids ◽

Solar System ◽

Hydrogen Cyanide ◽

Nitrogen Heterocycles ◽

Laboratory Studies ◽

Heterogeneous Solids ◽

The Many ◽

Comet Halley ◽

The Impact ◽

By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

Download Full-text

Neuronal and Extraneuronal Uptake of 3H-Norepinephrine in the Heart of the Active Bat: An Electron Microscopic Radioautographic Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073052 ◽

1973 ◽

Vol 31 ◽

pp. 522-523

Author(s):

Martin Hagopian ◽

Michael D. Gershon ◽

Eladio A. Nunez

Keyword(s):

Smooth Muscle ◽

Monoamine Oxidase ◽

Vascular Smooth Muscle ◽

Cardiac Muscle ◽

Maximum Rate ◽

External Medium ◽

Extraneuronal Uptake ◽

Electron Microscopic ◽

Cardiac Tissues ◽

High Affinity

The ability of cardiac tissues to take up norepinephrine from an external medium is well known. Two mechanisms, called Uptake and Uptake respectively by Iversen have been differentiated. Uptake is a high affinity system associated with adrenergic neuronal elements. Uptake is a low affinity system, with a higher maximum rate than that of Uptake. Uptake has been associated with extraneuronal tissues such as cardiac muscle, fibroblasts or vascular smooth muscle. At low perfusion concentrations of norepinephrine most of the amine taken up by Uptake is metabolized. In order to study the localization of sites of norepinephrine storage following its uptake in the active bat heart, tritiated norepinephrine (2.5 mCi; 0.064 mg) was given intravenously to 2 bats. Monoamine oxidase had been inhibited with pheniprazine (10 mg/kg) one hour previously to decrease metabolism of norepinephrine.

Download Full-text

Cognitive Aging in a Precision Sport Context

European Psychologist ◽

10.1027/1016-9040.1.3.166 ◽

1996 ◽

Vol 1 (3) ◽

pp. 166-179 ◽

Cited By ~ 6

Author(s):

Bo Molander ◽

Lars Bäckman

Keyword(s):

Older Adult ◽

Cognitive Abilities ◽

Cognitive Aging ◽

Motor Performance ◽

Intervention Programs ◽

Laboratory Studies ◽

High Arousal ◽

Memory And Attention ◽

Age Related ◽

Principal Finding

Highly skilled miniature golf players were examined in a series of field and laboratory studies. The principal finding from these studies is that young and young adult players (range = 15-38 years) score equally well or better in competition than in training whereas older adult players (range = 46-73 years) perform worse in competitive events than under training conditions. It was also found that the impairment in motor performance on the part of the older players is associated with age-related deficits in basic cognitive abilities, such as memory and attention. These results support the hypothesis that older players may be able to compensate for age-related deficits under relaxed conditions, but not under conditions of high arousal. The possibility of improving the performance of the older players in stressful situations by means of various intervention programs is discussed.

Download Full-text

Automation Surprise

Aviation Psychology and Applied Human Factors ◽

10.1027/2192-0923/a000113 ◽

2017 ◽

Vol 7 (1) ◽

pp. 28-41 ◽

Cited By ~ 4

Author(s):

Robert J. de Boer ◽

Karel Hurts

Keyword(s):

Flight Control ◽

Representative Sample ◽

Aviation Safety ◽

Control Mode ◽

Cognitive Errors ◽

Laboratory Studies ◽

Airline Pilots ◽

Flight Operations ◽

Widespread Phenomenon ◽

Few Data

Abstract. Automation surprise (AS) has often been associated with aviation safety incidents. Although numerous laboratory studies have been conducted, few data are available from routine flight operations. A survey among a representative sample of 200 Dutch airline pilots was used to determine the prevalence of AS and the severity of its consequences, and to test some of the factors leading to AS. Results show that AS is a relatively widespread phenomenon that occurs three times per year per pilot on average but rarely has serious consequences. In less than 10% of the AS cases that were reviewed, an undesired aircraft state was induced. Reportable occurrences are estimated to occur only once every 1–3 years per pilot. Factors leading to a higher prevalence of AS include less flying experience, increasing complexity of the flight control mode, and flight duty periods of over 8 hr. It is concluded that AS is a manifestation of system and interface complexity rather than cognitive errors.

Download Full-text