The tonically acting pulmonary receptors innervated by C fibres

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Action du rayonnement X sur la croissance de la plantule d'orge

Summary We have reproduced inHordeum the phenomenon described bySchwartz: absence of proportionality at certain dosages, between the dose of roentgen rays and the biological effect when one irradiates dry seeds and measures the growth of the coleoptile. Cytological analysis shows an enlargement of the epidermic cells of the coleoptiles up to 500.000 r and a decrease of the number of mitosis up to 200.000 r dose at which the mitotic inhibition is nearly complete.The phenomenon described bySchwartz disappears progressively if one waits 3 to 20 days between irradiation and sowing.     

The mechanism of reactions catalyzed by thiamine pyrophosphate

Zusammenfassung Es wird ein Mechanismus für verschiedene enzymatische Reaktionen, bei denen Thiaminpyrophosphat als Coferment wirkt, vorgeschlagen.     

Versuche auf dem Gebiet der Lokalanästhesie mit protrahierter Wirkung. III

Summary The addition of simple quaternary salts (as I and II) to solutions of local anaesthetics, effects a pronounced prolongation of the time of complete infiltration anaesthesia. These salts have no effect on the time of surface anaesthesia. Other pharmacological characteristics of these mixtures were also determined.     

Derivate des 6,11-Dihydrodibenz(b,e)thiepins,eine neue Gruppe von psychotropen Substanzen

Summary Reactions of phthalide and 6-chlorophthalide with sodium salts of thiophenols gaveo-(phenylmercaptomethyl)benzoic acids (III), which were cyclized by the action of polyphosphoric acid to 6, 11-dihydrodibenz(b,e)-thiepin-11-ones (1). These ketones were treated with 3-di-methylaminopropylmagnesium chloride and other basic Grignard reagents and the products (IV) dehydrated to a series of 11-(aminoalkylidene)-6,11-dihydrodibenz(b,e)-thiepins (V), the hydrochlorides of which show psychotropic activity.

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6. Mitt. Synthetische Ataractica, 5. Mitt. siehe eskoslov. farm.11, im Druck (1962).     

Über die tuberkulostatische Aktivität von 2,5-Bis-(aminooxymethyl)-3,6-diketopiperazin,eines Umwandlungsproduktes des Cycloserins

Summary It has been ascertained that racemic 2,5-bis-(aminooxymethyl)-3,6-diketopiperazine, being a transformation product ofD,L-cycloserine, possesses the same effect againstMycobacterium tuberculosis asD,L-cycloserine itself.     

Two-state model ofParamecium bursaria thigmotaxis

A theoretical framework has been developed for analysis of the interaction betweenParamecium bursaria and a glass surface. Adhesion to and detachment from a solid substrate were considered in the model as transitions between alternative states in cell behavior: (a) swimming, and (b) motionless (positive thigmotactic) state. According to the model and experimental data, a change in the fraction of swimming cells is described by a negative exponential course. The proposed model allows positive thigmotaxis, generally referred to in the literature simply as thigmotaxis, to be considered as the rate-constant of transition into the motionless state. This approach permits quantitative determination of thigmotaxis, and reveals its dependence on the phase of culture growth and the type of medium surrounding the cells. In the mineral maintenance solution, paramecia from the stationary phase of growth swim more slowly than those in the logarithmic phase of growth, and show enhanced thigmotaxis. However, a general relationship between thigmotaxis and swimming speed was not established.     

The induction of secondary seed dormancy by oxygen deficiency in a barnyard grassEchinochloa crus-galli

At 25°C, secondary dormancy was induced in seeds ofE. crus-galli exposed for 100 days to oxygen deficiency. By contrast, hypoxia did not induce dormancy at 15°C or prevent dormancy termination at 7°C. Secondary dormancy was terminated after 2 months stratification at 7°C. Oxygen deficiency may increase the proportion of dormant seeds in the soil, and affect the dynamics of the barnyard-grass soil seed bank.We thank Miss Jitka Králová for her excellent technical assistance.