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Abstract
In order to reveal the reactivity of toluenethiols, the hydrogen isotope exchange reaction between one of three toluenethiols (o
–,m
–, andp
–) and poly (vinyl alcohol) labeled with tritium was observed at 50 
90°C. The reaction was analyzed with both the data obtained and theA
-McKay plot method, and the following has been quantitatively clarified: (1) the reactivity order of toluenethiols is (o
–>(m
–)>(p
–); (2) the temperature dependences of the reactivity of toluenethiols are nearly equal; (3) the reactivity of benzenethiol is considerably decreased by the CH3 group bonded to the ortho position.
Abstract
Making a costly apology or inflicting self-punishment after an unintentional transgression can serve as a costly signal of the transgressor's benign intention. In the present research, after an unintentional transgression (i.e., unequal resource allocation between themselves and a partner), participants were provided with an opportunity to send an apology message to their partner (in Experiments 1 and 2) or to privately deduct some amount from their own reward (in Experiments 2 and 3). Across these experiments, approximately half of the participants indicated their willingness to incur some cost to produce these costly signals. In Experiment 1, neither history nor expectation of interaction with a partner altered the frequency of a costly apology. In Experiment 2, despite explicit instructions that their partner would not be informed whether they had inflicted the self-punishment, the frequency of self-punishment was approximately equal to that of a costly apology. These results suggest that the two types of costly signal were not solely directed at the victim. Experiment 3 revealed that these costly signallers endorsed the equality principle more than the non-signallers. This result is consistent with the idea that the two forms of costly signals serve to protect the signaller's reputation as a fair person.
Abstract
A new spectrophotometric determination of technetium has been developed by means of the solvent extraction of tris(1,10-phenanthroline)iron(II) ([Fe(phen)3
2+]) with pertechnetate into nitrobenzene. The concentration of technetium can be determined by measuring the characteristic absorbance at 516 nm (
=11,700M–1·cm–1) in the organic phase. An important feature of the proposed method is that the concentration of pertechnetate can be determined without complicated processes such as the reduction of pertechnetate and the subsequent formation of a colored chelate.
Abstract
Poor sleep increases pain, at least in part, by disrupting endogenous pain modulation. However, the efficacy of endogenous analgesia in sleep-deprived subjects has never been tested. To assess this issue, we chose three different ways of triggering endogenous analgesia: (1) acupuncture, (2) acute stress, and (3) noxious stimulation, and compared their ability to decrease the pronociceptive effect induced by REM-SD (Rapid Eye Movement Sleep Deprivation) with that to decrease inflammatory hyperalgesia in the classical carrageenan model. First, we tested the ability of REM-SD to worsen carrageenan-induced hyperalgesia: A low dose of carrageenan (30 µg) in sleep-deprived Wistar rats resulted in a potentiated hyperalgesic effect that was more intense and longer-lasting than that induced by a higher standard dose of carrageenan (100 µg) or by REM-SD alone. Then, we found that (1) acupuncture, performed at ST36, completely reversed the pronociceptive effect induced by REM-SD or by carrageenan; (2) immobilization stress completely reversed the pronociceptive effect of REM-SD, while transiently inhibited carrageenan-induced hyperalgesia; (3) noxious stimulation of the forepaw by capsaicin also reversed the pronociceptive effect of REM-SD and persistently increased the nociceptive threshold above the baseline in carrageenan-treated animals. Therefore, acupuncture, stress, or noxious stimulation reversed the pronociceptive effect of REM-SD, while each intervention affected carrageenan-induced hyperalgesia differently. This study has shown that while sleep loss may disrupt endogenous pain modulation mechanisms, it does not prevent the activation of these mechanisms to induce analgesia in sleep-deprived individuals.
The pond snail, Lymnaea stagnalis , can locomote on its back utilizing the surface tension of the water. We have called this form of movement ‘back-swimming’. In order to perform this behavior, the snail must flip itself over on its back so that its foot is visible from above. Little is known about the mechanism of this back-swimming. As a first step for the elucidation of this mechanism, we measured the speed of back-swimming of Lymnaea at the different times of the day. They back-swam significantly faster in the morning than just before dark. These data are consistent with our earlier findings on circadian-timed activity pattern in Lymnaea. Lymnaea appear to secrete a thin membrane-like substance from their foot that may allow them to back-swim. To confirm the existence of this substance and to examine whether this substance is hydrophobic or hydrophilic, we applied a detergent onto the foot during back-swimming. A single drop of 1% Tween 20 drifted Lymnaea away that were still kept at the water surface. These results suggest that Lymnaea secrete a hydrophobic substance from their foot that floats to the water surface allowing Lymnaea to back-swim.
