Effect of non-catecholic 2-aminotetralin derivatives on dopamine metabolism in the rat striatum

The concentrations of dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured in the striatum of rats after i.p. injection of dipropyl-2-aminotetralin and the four positional isomers of monohydroxy-dipropyl-2-aminotetralin. All compounds except 8-OH dipropylaminotetralin caused a decrease in DOPAC- and HVA-concentrations. In addition, 5-OH-dipropylaminotetralin produced a small elevation in DA concentrations. In contrast, 7-OH dipropylaminotetralin, in doses of 100 mumol/kg and more, decreased DA to 50% and initially increased HVA and DOPAC to about 200%, after which the concentrations of the metabolites fell to 30% or less. The 5-OH isomer was found to be the most potent compound, decreasing HVA concentrations to 70% at a dose of 0.14 mumol/kg. The potencies are compared to those of catechol-group containing DA-agonists such as apomorphine and N,N-dipropyl-5,6-dihydroxy-2-aminotetralin. In addition, a comparison is made with reported behavioural data. It is suggested that the more active N-alkylated 2-aminotetralins have a conformation which corresponds to that of the alpha rotamer of dopamine.     

Thirty wrongs do not make a right: Reply to Guilford.

Considers that J. P. Guilford's (see PA, Vol 53:Issue 1) reply to the authors' criticisms of his factor analysis of his structure-of-intellect model has failed to come to grips with evidence indicating that if the number of targeted variables for each factor is 3 or fewer, Procrustes factoring provides no better evidence for structure-of-intellect theory than for any of an infinity of other arbitrarily determined theories. Under these conditions factors can be rotated in such a way as to suggest support for almost any desired solution, and one such solution can be that labeled a replication. Hence the factorial invariance claimed under such conditions can indicate only consistency in the researcher and his methods, not in the phenomena studied. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Korrosion nichtrostender austenitischer Stähle in (kondensierender) chloridhaltiger Salpetersäure

Corrosion of austenitic stainless steels in (condensing) nitric acid containing chlorides The corrosion parameters involved in the behaviour of austenitic stainless steels and nickelbase alloys in chloride containing nitric acid are being stated. Investigation of the corrosion resistance of the austenitic stainless steel 1.4306, ESR grade for application in nitric acid, in nitric acid condensates containing small amounts of chlorides. The condensates were formed from boiling nitric acids of molarities 6 to 10 containing 15 to 45 mg chlorides/1. The calculated corrosion rates of < 1 μm/y can be considered rather small. Especially in cases of insufficient wetting of the heat exchanger surfaces, however, local roughening and pitting corrosion is to be expected, mostly under rust-colored, chloride-containing deposits. The intensity of pitting corrosion increases with increasing chloride contents of the nitric acid solutions that evaporate. The sealing surfaces consisting of steel 1.4306 and PTFE did not exhibit any crevice corrosion. Nitric acid grade ESR-1.4306 definitely does not suffice requirements as described in this paper. It is suggested to use stainless steels which exhibit an improved resistance against chlorides and, at the same time, a high resistance against nitric acid attack. The following steel grades may be considered: X 1 CrNi 25 21 (Mat. No. 1.4335), X 2 CrNiMoN 25 22 2 (Mat. No. 1.4466) and/or X 1 NiCrMoCuN 31 27 4 (Mat. No. 1.4563).     

Plattieren — eine kostengünstige Alternative für den Einsatz metallischer Werkstoffe in der Chemietechnik

Plating – a cost-effective alternative to the use of metallic materials in chemical engineering. The paper treats plated semifinished products used in chemical plant construction. Advantages and draw-backs of various plating processes such as welding, rolling, or by detonation are discussed as well as post plating processing such as hot forming or joining with regard to measures to be observed. Selection of the most suitable technique should be based on considerations of materials producers, workshops, and chemical plants.     

Chlorid-Abspaltung aus o-Dichlorbenzol-Wasser-Gemischen im neutralen und sauren Bereich und ihre Bedeutung für die Werkstoffauswahl

Hydrolysis of o-dichlorobenzene-water-mixtures In neutral to acid conditions and its importance when selecting materials of construction Water-saturated o-dichlorobenzene and o-dichlorobenzene-watermixtures were investigated for hydrolysis under neutral and acid conditions and the exclusion of light. Some measurements were also taken in presence of iron oxides and also metallic iron. Chloride ion generation grows with increasing temperatures and – at 175 °C – also with time. The greatest chloride ion generation was observed when water saturated o-dichlorobenzene reacted in the presence of iron oxides. In the presence of sulfuric acid the maximum chloride ion generation was detected at 175 °C and a sulfuric acid concentration of 3 · 10^?3 mol/l. The hydrolysis products were monochlorobenzene and o-chlorophenol. The chloride ion generation from o-dichlorobenzene in neutral and slightly acid media is important when selecting materials of construction for chemical equipment.     

Deckschichtbildung und Korrosionsverhalten des hochsiliciumlegierten austenitischen Sonderstahls X 2 CrNiSi 18 15 in Salpetersäuren

The Formation of Surface Films and the Corrosion Resistance of the Silicon Containing Austenitic Steel X 2 CrNiSi 18 15 in Nitric Acids The oxide layers consist of two parts: the lower one is mainly Croxide, the upper one is SiO₂. ESCA and AAS measurements were made in order to study the formation of the surface layer on the austenitic steel X2 CrNiSi 18 15 in nitric acids. A film, which is chromium oxide, is formed first. On top of this film a second film consisting of SiO₂ grows. The elements nickel and manganese are not found in the formation of the oxide films. Immediately below the oxide layer the steel is enrichened with chromium and depleted of iron. In order to find the in some cases very small corrosion rates (5 · 10^?5 mm · a^?1) in a reproducible manner, the amounts of iron, chromium and nickel which had been dissolved were measured by means of the AAS method as a function of time. For stationary samples apparent activation energies of 65.2 kJ/Mol (azeotropic nitric acid) and 37.5 kJ/Mol (highly concentrated nitric acid), respectively, were found. These data confirm the assumption that the corrosion rate is determined by reactions at the phase boundaries. No appreciable influence of the flow velocity on the corrosion rate was detected.     

Good news for commuters: better and faster rapid transit

Rail signal systems have traditionally been employed to prevent collision of trains while permitting them to adhere to a schedule that is adequate for moving passengers and/or freight. In today's rapid-transit systems, however, the corollary objectives of a signal system?namely, controlling the speed of trains, increasing the capacity of the line, and minimizing schedule disruptions caused by transient disturbances in train operations?are critical to providing satisfactory service to passengers.     

Engineering thermal stability in RNA phage capsids via disulphide bonds

The RNA bacteriophages, a group that includes phages Qbeta and MS2, have a number of potential bionanotechnological applications, including cell specific drug delivery and as substrates for the formation of novel materials. Despite extensive sequence identity between their coat protein subunits, and an almost identical three-dimensional fold, Qbeta and MS2 capsids have dramatically different thermal stabilities. The increased stability of Qbeta has been correlated with the inter-subunit disulphide bonds present in that capsid and not present in MS2. We have tested this hypothesis directly using mass spectrometry. Analysis of the dissociated coat protein subunits suggests that inter-molecular disulphides are formed at the capsid five-fold but may not be at the three-fold axes. This conclusion has been tested by engineering disulphide cross-links into either the five-fold or three-fold positions of the recombinant MS2 capsid. Five-fold cross-linking results in a mutant with stability properties similar to those of Qbeta. Three-fold cross-linking results in a mutant unable to assemble T = 3 shells, implying that five-fold structures are on pathway to capsid assembly in these phages. The results demonstrate how it is possible to redesign the physical properties of phage shells and may be of general relevance to future applications of viruses and virus-like particles.