The Autoxidation of Rubber and Mechanisms of Protection against Oxygen

1947 ◽  
Vol 20 (4) ◽  
pp. 972-977
Author(s):  
Jean Le Bras

Abstract The autoxidation of ethylenic hydrocarbons has been the object of various investigations, and various authors, among whom Engler and Stephens in particular might be mentioned, have studied the part played by peroxides. Up to 1936 it was generally believed that structurally these peroxides represent the fixation of one molecule of oxygen on the double bond. About this time, however, Criegee on the one hand, and Hock and Sehrader on the other, published papers almost simultaneously on the preparation and constitution of cyclohexene peroxide, in which they demonstrated that the latter can exist in the form of a hydroperoxide.Later these investigators offered further proof in favor of this view by extending the reaction to other hydrocarbons. These studies led to the important conclusion that ethylenic hydrocarbons have two sensitive points: the double bond itself, and the carbon in α-position to this double bond; hence there are two forms of the peroxide, the first of which retains its unsaturated character.

Author(s):  
Ángela Di Tullio ◽  
Andrés Saab ◽  
Pablo Zdrojewski

This chapter places Clitic Doubling in Argentinean Spanish into the broad perspective of pronominal doubling phenomena. A series of diagnostics is presented based on the interaction of Clitic Doubling with its PF/pragmatic effects, on the one hand, and its syntactic/LF effects, on the other. An important conclusion is that Clitic Doubling must be kept apart from Clitic Right Dislocation and Clitic Left Dislocation. Clitic Doubling is thus conceived of the morphological reflex of the abstract composition of object DPs; concretely, it is an A-dependency triggered whenever the object possesses a [person]-feature, an observation called the Person Feature Condition. So, under the minimal assumption that [3P] features can be optionally encoded on lexical DPs in Argentinean Spanish, but that it is only specified for pronouns in other Spanish dialects, variation facts associated with this phenomenon are explained. By the same token, the different behavior of doubled and nondoubled objects in several syntactic/LF configurations also follows.


2000 ◽  
Vol 72 (9) ◽  
pp. 1769-1772 ◽  
Author(s):  
Michael A. Hofmann ◽  
Uwe Bergsträßer ◽  
Manfred Regitz

Phosphatriafulvenes readily react with kinetically stabilized phosphaalkynes. Depending on the substituent at the phosphorus atom of the phosphatriafulvene, different six-membered phosphaheterocycles can be isolated. On the one hand, 1,3-diphosphabenzenes are formed, which can be isomerized thermally to diphospha dewarbenzenes or complexed by Cr(CO)3. On the other hand, 1,3-diphosphaisobenzenes are thus available. They are converted to bicyclic six-membered allenes via 1,3-dipolar cycloaddition to the P/C double bond.


2004 ◽  
Vol 23 (3) ◽  
pp. 52-60 ◽  
Author(s):  
J. G. Maree ◽  
E. C. Olivier ◽  
A. C. Swanepoel

South African learners’ insufficient achievement in mathematics is of concern to everyone involved in learning facilitation i mathematics. Interested parties constantly seek ways in which learners’ insight into and achievement in mathematics can be improve in order to equip them to attain a successful life. In this regard mathematics olympiads worldwide are regarded as excellent mechanism to, on the one hand, identify talented learners and improve their problem solving skills in mathematics, and on the other hand, to prepare learners for future study in the field of mathematics in general. This article analyses several aspects of the 2004 Sout African Mathematics Olympiad and offers several suggestions. An important conclusion is that although the Harmony South Africa Mathematics Olympiad accomplishes its goal, it still does not reach as many learners and educators as one would hope. The idea of the Harmony South African Mathematics Olympiad will probably only be realised if all schools are provided with proper facilitie and if the standard of mathematics education is simultaneously improved on a national level. It is therefore vital that all intereste parties discuss and reassess this matter promptly and incisively.


1979 ◽  
Vol 57 (2) ◽  
pp. 213-217 ◽  
Author(s):  
Jean-Pierre Corbet ◽  
Claude Benezra

Isoalantolactone and α-methylene-γ-butyrolactone were separately treated with NaSPh, transformed into sulfoxides, and rearranged under Pummerer conditions (Ac2O + (CF3CO)2O). The Pummerer products were hydrolyzed, oxidized, and decarboxylated resulting in the formation of 13-norisoalantolactone (with migration of the exo-C(4) double bond into position C(4)—C(5)) on the one hand and of γ-butyrolactone on the other. The isomeric norisoalantolactone 17 is a starting material for the synthesis of 14C-labelled alantolactone, 18.


1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2005 ◽  
Vol 44 (03) ◽  
pp. 107-117
Author(s):  
R. G. Meyer ◽  
W. Herr ◽  
A. Helisch ◽  
P. Bartenstein ◽  
I. Buchmann

SummaryThe prognosis of patients with acute myeloid leukaemia (AML) has improved considerably by introduction of aggressive consolidation chemotherapy and haematopoietic stem cell transplantation (SCT). Nevertheless, only 20-30% of patients with AML achieve long-term diseasefree survival after SCT. The most common cause of treatment failure is relapse. Additionally, mortality rates are significantly increased by therapy-related causes such as toxicity of chemotherapy and complications of SCT. Including radioimmunotherapies in the treatment of AML and myelodyplastic syndrome (MDS) allows for the achievement of a pronounced antileukaemic effect for the reduction of relapse rates on the one hand. On the other hand, no increase of acute toxicity and later complications should be induced. These effects are important for the primary reduction of tumour cells as well as for the myeloablative conditioning before SCT.This paper provides a systematic and critical review of the currently used radionuclides and immunoconjugates for the treatment of AML and MDS and summarizes the literature on primary tumour cell reductive radioimmunotherapies on the one hand and conditioning radioimmunotherapies before SCT on the other hand.


2017 ◽  
Vol 47 (188) ◽  
pp. 487-494
Author(s):  
Daniel Mullis

In recent years, political and social conditions have changed dramatically. Many analyses help to capture these dynamics. However, they produce political pessimism: on the one hand there is the image of regression and on the other, a direct link is made between socio-economic decline and the rise of the far-right. To counter these aspects, this article argues that current political events are to be understood less as ‘regression’ but rather as a moment of movement and the return of deep political struggles. Referring to Jacques Ranciere’s political thought, the current conditions can be captured as the ‘end of post-democracy’. This approach changes the perspective on current social dynamics in a productive way. It allows for an emphasis on movement and the recognition of the windows of opportunity for emancipatory struggles.


1996 ◽  
pp. 13-23
Author(s):  
Mykhailo Babiy

Political ideological pluralism, religious diversity are characteristic features of modern Ukrainian society. On the one hand, multiculturalism, socio-political, religious differentiation of the latter appear as important characteristics of its democracy, as a practical expression of freedom, on the other - as a factor that led to the deconsocialization of society, gave rise to "nodal points" of tension, confrontational processes, in particular, in political and religious spheres.


2003 ◽  
pp. 15-26
Author(s):  
P. Wynarczyk
Keyword(s):  
The Core ◽  

Two aspects of Schumpeter' legacy are analyzed in the article. On the one hand, he can be viewed as the custodian of the neoclassical harvest supplementing to its stock of inherited knowledge. On the other hand, the innovative character of his works is emphasized that allows to consider him a proponent of hetherodoxy. It is stressed that Schumpeter's revolutionary challenge can lead to radical changes in modern economics.


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