scholarly journals On the change in the conduction velocity in the nerve during the development of parabiosis

1907 ◽  
Vol XIV (1) ◽  
pp. 47-70
Author(s):  
Dmitriy V. Polumordvinov

General nervous physiology still takes into account a kind of doctrine of the separation of the basic properties of nerves, according to which one of the properties can be changed without changing the other, such as, for example. destroy conduction while maintaining excitability. In the development of this doctrine, a very significant role belongs to the small and simple experiment of Grungayen, who studied the stepwise effect of carbon dioxide on the excised frog nerve. Exposing a part of the nerve to the influence of carbon dioxide, Grungagen found that excitability in the anesthetized area dropped markedly, while, upon stimulation of the central end, contractions continued to be obtained at the same current strength.

2013 ◽  
Vol 316-317 ◽  
pp. 919-922
Author(s):  
Wen Yuan Xu ◽  
Jing Tang ◽  
Wei Long ◽  
Lin Hu ◽  
San Guo Hong

Abstract. A mechanism of the dehydrogen-reforming of methane with carbon dioxide over Pt, Rh and Ru under a supercritical condition was investigated by B3LYP/Lanl2dz and MP2 methods. Results show that the reforming reaction divided into six steps under the supercritical state, the rate-determining steps of the reaction over the different transition metals were not the same. Dehydrogenation plays a significant role pin the process of reforming reaction. For Pt, Rh and Ru, the easiest step is the same-step 1. All of the other steps were exothermic reactions. The process of reaction over Pt, Rh and Ru were similar with the reaction over Ni. For Pt, the CO2 Specific activities of four kinds of the transition metals were in the order: Pt>Rh>Ru.


1919 ◽  
Vol 1 (6) ◽  
pp. 613-621 ◽  
Author(s):  
A. R. Moore

1. With the indicator method of Haas, the rates of carbon dioxide production have been measured in the case of the sciatic nerve, various parts of the brain, and the sartorius muscle of the frog. The rate of respiration of the sciatic nerve is from 10 to 30 per cent of that of the other tissues, varying somewhat with the individual. 2. Stimulation of the sciatic nerve with induction shocks sufficient to induce tetanus of the muscle does not increase the output of carbon dioxide from the sciatic nerve, even if continued as long as 30 minutes. Sartorius muscle used as a control showed a marked increase in carbon dioxide production upon relaxation after contraction resulting from such stimulation. 3. These facts indicate that the nerve impulse does not depend upon processes leading to the production of carbon dioxide.


1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.


Author(s):  
E. Tendayi Achiume

This chapter uses the trajectory of the Southern African Development Community (“SADC”) Tribunal to chart sociopolitical constraints on international judicial lawmaking. It studies the SADC Tribunal backlash case, which paved the way for a curtailment of the Tribunal’s authority, stripping the Tribunal of both private access and its jurisdiction over human rights. Showing how jurisprudential engagement with sociopolitical context plays a significant role in explaining the Tribunal's loss of authority, the chapter introduces the concept of sociopolitical dissonance. Sociopolitical dissonance is a state that results when a legal decision contradicts or undermines deeply held norms that a given society or community forms on the basis of its social, political, and economic history. Sociopolitical resonance, on the other hand, describes the quality of affirming or according with a given society's norms as informed by its sociopolitical history.


2021 ◽  
Vol 13 (15) ◽  
pp. 8333
Author(s):  
Mirella Soyer ◽  
Koen Dittrich

In this study we investigate how consumers in The Netherlands can be persuaded to adopt sustainable practices when purchasing, using and disposing of clothes. This study investigates the attitude-behavior gap for the sustainable choices for purchase, use and disposing of clothes. For each consumption phase we ran a two-step multiple regression. The findings showed that the importance of the factors vary in the three consumption phases. For purchasing and disposal decisions, the core motivator social motivation predicts sustainable practices best, while it has no role in the usage phase. The factor ability appeared to have a significant role in the disposal phase, but not in the other phases. Finally, the trigger appears to lower the consumers’ ability in the purchasing phase, while it enhances the core motivator social evaluation in the disposal phase.


1993 ◽  
Vol 289 (1) ◽  
pp. 117-124 ◽  
Author(s):  
S Roche ◽  
J P Bali ◽  
R Magous

The mechanism whereby gastrin-type receptor and muscarinic M3-type receptor regulate free intracellular Ca2+ concentration ([Ca2+]i) was studied in rabbit gastric parietal cells stimulated by either gastrin or carbachol. Both agonists induced a biphasic [Ca2+]i response: a transient [Ca2+]i rise, followed by a sustained steady state depending on extracellular Ca2+. Gastrin and carbachol also caused a rapid and transient increase in Mn2+ influx (a tracer for bivalent-cation entry). Pre-stimulation of cells with one agonist drastically decreased both [Ca2+]i increase and Mn2+ influx induced by the other. Neither diltiazem nor pertussistoxin treatment had any effect on agonist-stimulated Mn2+ entry. Thapsigargin, a Ca(2+)-pump inhibitor, induced a biphasic [Ca2+]i increase, and enhanced the rate of Mn2+ entry. Preincubation of cells with thapsigargin inhibits the [Ca2+]i increase as well as Mn2+ entry stimulated by gastrin or by carbachol. Thapsigargin induced a weak but significant increase in Ins(1,4,5)P3 content, but this agent had no effect on the agonist-evoked Ins(1,4,5)P3 response. In permeabilized parietal cells, Ins(1,4,5)P3 and caffeine caused an immediate Ca2+ release from intracellular pools, followed by a reloading of Ca2+ pools which can be prevented in the presence of thapsigargin. We conclude that (i) gastrin and carbachol mobilize common Ca2+ intracellular stores, (ii) Ca2+ permeability secondary to receptor activation involves neither a voltage-sensitive Ca2+ channel nor a GTP-binding protein from the G1 family, and (iii) agonists regulate common Ca2+ channels in depleting intracellular Ca2+ stores.


1963 ◽  
Vol 22 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Joan Bondurant

The title of this essay begins with the word traditional and it moves towards the idea of change. As is well known, these terms—tradition and change—are not opposites, nor are they to be understood in contradistinction to one another. It is important in this context to avoid the temptation to treat them as contradictory or to draw contrasts between what one considers on the one hand traditional, and on the other, changing. One cannot accurately speak of what was as over against what will be, or what is becoming. Nor can one view the ancient as opposed to that which is modern. Clearly, the opposite of change is permanence and persistence, and is not—at least not necessarily—to be couched in terms of the traditional. One need only to remind oneself that among the most compelling elements in the West's intellectual history is the idea of progress, to understand that there are indeed traditions in which the notion of change itself has played a significant role. And so it does not follow that "traditional Indian polity" is a set of concepts to be placed over against the "dynamics of change"—quite the contrary, as I shall try to show in what follows.


2020 ◽  
Vol 16 (4) ◽  
pp. 343-377
Author(s):  
Adel Saadi ◽  
Ramdane Maamri ◽  
Zaidi Sahnoun

The Belief-Desire-Intention (BDI) model is a popular approach to design flexible agents. The key ingredient of BDI model, that contributed to concretize behavioral flexibility, is the inclusion of the practical reasoning. On the other hand, researchers signaled some missing flexibility’s ingredient, in BDI model, essentially the lack of learning. Therefore, an extensive research was conducted in order to extend BDI agents with learning. Although this latter body of research is important, the key contribution of BDI model, i.e., practical reasoning, did not receive a sufficient attention. For instance, for performance reasons, some of the concepts included in the BDI model are neglected by BDI architectures. Neglecting these concepts was criticized by some researchers, as the ability of the agent to reason will be limited, which eventually leads to a more or less flexible reasoning, depending on the concepts explicitly included. The current paper aims to stimulate the researchers to re-explore the concretization of practical reasoning in BDI architectures. Concretely, this paper aims to stimulate a critical review of BDI architectures regarding the flexibility, inherent from the practical reasoning, in the context of single agents, situated in an environment which is not associated with uncertainty. Based on this review, we sketch a new orientation and some suggested improvements for the design of BDI agents. Finally, a simple experiment on a specific case study is carried out to evaluate some suggested improvements, namely the contribution of the agent’s “well-informedness” in the enhancement of the behavioral flexibility.


1922 ◽  
Vol 26 (140) ◽  
pp. 325-330
Author(s):  
S. Heckstall Smith

If the thought of another war troubles you, then don't read this article. If you would rather say to yourself as the Secretary of State said to the Air Conference, “ There won't be another war for ten years, so why worry? ” then no doubt you will think with him that it is better to let other nations have alk the bother and expense of trying to advance; after all, we are jolly fine fellows and can soon pick up. If, on the other hand, you have imagination which gives you a nasty queasy sensation when you think of what might be, then perhaps the following notes, albeit disjointed and mostly stale, may at least conjure up in you thoughts of your own on the subject. This is all that is needed to help, our advancement in the air–the stimulation of spoken and written thoughts by the British nation, for if every taxpayer in the British Empire says “ Air Force,” then the Press and Parliament will say it too.


Neurosurgery ◽  
1991 ◽  
Vol 28 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Fumio Shima ◽  
Takato Morioka ◽  
Shozo Tobimatsu ◽  
Omiros Kavaklis ◽  
Motohiro Kato ◽  
...  

Abstract To improve the localization of stereotactic targets, somatosensory evoked potentials (SEPs) were recorded from the thalamus and subthalamic area using a specially designed semimicroelectrode in 61 patients and a conventional “macroclectrode” in 17 patients. By means of the semimicroelectrode, median nerve stimulation evoked two distinct SEPs, consisting of a diphasic wave with a huge positivity restricted to the nucleus ventrocaudalis (Vc) and a triphasic wave of lower amplitude with a major negativity in the ventral part of the nucleus ventrointermedius (Vim) and nucleus ventrooralis posterior (Vop) as well as the subthalamic lemniscal pathway. The Vim-Vc junction could thus be clearly delineated by an abrupt transition of SEPs from one type to the other with a precision of 1 mm. The parvicellular part of the Vc (Vcpc). situated in its basal region, was distinguishable from the Vc proper by a significant reduction of the positivity elicited by stimulation of the median nerve and by a rapid growth of a diphasic SEPs to stimulation of the posterior tibial nerve. In the other thalamic nuclei, stimulation of the median nerve elicited triphasic SEPs of a very small amplitude, suggesting a volume conduction current from the lemniscal pathway. With the macroclectrode, the positivity in the Vc was sensitive to electrode manipulation and the thalamic nuclei could not be distinctly outlined. SEP monitoring using the semimicroelectrode significantly improved the precision of target localization, which allowed minimizing of the volume of the therapeutic lesion without losing surgical effectiveness, while avoiding complications associated with increased penetration of the coagulating electrode. It is suggested that recording serial thalamic SEPs with the semimicroelectrode is a practical method to refine stereotactic targets in the thalamus.


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