共查询到20条相似文献,搜索用时 46 毫秒
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Atta-ur-Rahman Anwer Basha Viqar Uddin Ahmad 《Cellular and molecular life sciences : CMLS》1976,32(12):1491-1492
Summary The reactions of Vilsmeir complexes of amides/imides with electrophiles afford the corresponding -substituted products in good yield. 相似文献
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Zusammenfassung Drei strukturelle Analoge des-MSH wurden synthetisiert und auf ihre Melanophoren-stimulierende Wirksamkeit untersucht. Für das Auftreten einer ausgeprägten biologischen Aktivität scheint die Anwesenheit einerN-Acetyl-Gruppe an dem Aminoende der Peptidkette wichtiger zu sein als das Vorhandensein der zwei ersten amino-endständigen Aminosäurereste der-MSH-Kette. 相似文献
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We reconstruct essential features of Lagrange’s theory of analytical functions by exhibiting its structure and basic assumptions,
as well as its main shortcomings. We explain Lagrange’s notions of function and algebraic quantity, and we concentrate on
power-series expansions, on the algorithm for derivative functions, and the remainder theorem—especially on the role this
theorem has in solving geometric and mechanical problems. We thus aim to provide a better understanding of Enlightenment mathematics
and to show that the foundations of mathematics did not, for Lagrange, concern the solidity of its ultimate bases, but rather
purity of method—the generality and internal organization of the discipline. 相似文献
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《Studies in history and philosophy of science》2012,43(4):610-618
This paper compares the views of styles of science of Alistair Crombie and Ian Hacking with the notion of styles of art, as developed by Alois Riegl at the end of the 19th Century. Important similarities are noted, notably in the conceptualization of the autonomy of styles. Riegl developed in particular the notion of Kunstwollen (“will to art”), which encompasses an implied relation to the world, in both a cognitive and an ethical sense, and a relation to the public of art. The latter aspect will be examined as the “role of the spectator”. Finally, a number of Riegl’s view on art are tentatively applied to styles of science. 相似文献
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Yasmina?Manso Javier?Carrasco Gemma?Comes Gabriele?Meloni Paul?A.?Adlard Ashley?I.?Bush Milan?Va?ák Juan?Hidalgo
Among the dementias, Alzheimer’s disease (AD) is the most commonly diagnosed, but there are still no effective drugs available for its treatment. It has been suggested that metallothionein-3 (MT-3) could be somehow involved in the etiology of AD, and in fact very promising results have been found in in vitro studies, but the role of MT-3 in vivo needs further analysis. In this study, we analyzed the role of MT-3 in a mouse model of AD, Tg2576 mice, which overexpress human Amyloid Precursor Protein (hAPP) with the Swedish mutation. MT-3 deficiency partially rescued the APP-induced mortality of females, and mildly affected APP-induced changes in behavior assessed in the hole-board and plus-maze tests in a gender-dependent manner. Amyloid plaque burden and/or hAPP expression were decreased in the cortex and hippocampus of MT-3-deficient females. Interestingly, exogenously administered Zn7MT-3 increased soluble Aβ40 and Aβ42 and amyloid plaques and gliosis, particularly in the cortex, and changed several behavioral traits (increased deambulation and exploration and decreased anxiety). These results highlight that the control of the endogenous production and/or action of MT-3 could represent a powerful therapeutic target in AD. 相似文献
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N. Brambaifa 《Cellular and molecular life sciences : CMLS》1988,44(1):45-47
Summary The binding of 16-phenoxy derivatives of prostaglandin (PG) F2 to rat luteal membranes, and also their abortifacient potency in pregnant rats, have been studied. Competitive binding studies with various PG-analogues were performed in ovaries of juvenile rats pretreated with PMSG and HCG, and in parallel studies the abortifacient potency of these substances was tested, in pregnant rats. It was observed that this class of derivatives bound to the PGF2 receptor as well as, or even better than the parent compound PGF2. Modifications in the carboxyl group at C-1 yielded derivatives with a higher affinity for the receptor, in decreasing order of effectiveness as follows:-COOR>COOH>OH. The data obtained from the binding studies also compared well with data on the abortifacient potency in pregnant rats. It is concluded that the addition of a phenoxy group to either the lower or upper side chain of PGF2 may augment the binding to the receptor as well as the biological responses induced by the post receptor effect. 相似文献
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F. V. DeFeudis P. Madtes J. Gervas-Camacho 《Cellular and molecular life sciences : CMLS》1977,33(3):340-342
Summary GABA (6×10–6 M) binding to synaptosome-enriched fractions of cat CNS exhibited a clear rostro-caudal gradient, whereas glycine (6×10–6 M) binding was greatest to particles of cerebellar cortex, and this was followed by medulla caudate nucleus cerebral cortex pons > corona radiata. Strychnine-SO4 (10–3 or 10–4 M) inhibited the binding of GABA and glycine in all brain regions studied; at 10–5 M this drug inhibited the binding of both GABA and glycine only to particles of the cerebral cortex.This study was supported by Centro Nacional Ramón y Cajal and Fundación Juan March. P. M. was a summer student from Eastern Nazarene College, Wollaston, Mass., USA. 相似文献
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Lamarine M Mornon JP Berezovsky N Chomilier J 《Cellular and molecular life sciences : CMLS》2001,58(3):492-498
Using a set of 372 proteins representative of a variety of 56 distinct globular folds, a statistical correlation was observed
between two recently revealed features of protein structures: tightened end fragments or 'closed loops', i. e. sequence fragments
that are able in three-dimensional (3D) space to nearly close their ends (a current parameter of polymer physics), and 'topohydrophobic
positions', i. e. positions always occupied in 3D space by strong hydrophobic amino acids for all members of a fold family.
Indeed, in sequence space, the distribution of preferred lengths for tightened end fragments and that for topohydrophobic
separation match. In addition to this statistically significant similarity, the extremities of these 'closed loops' may be
preferentially occupied by topohydrophobic positions, as observed on a random sample of various folds. This observation may
be of special interest for sequence comparison of distantly related proteins. It is also important for the ab initio prediction
of protein folds, considering the remarkable topological properties of topohydrophobic positions and their paramount importance
within folding nuclei. Consequently, topohydrophobic positions locking the 'closed loops' belong to the deep cores of protein
domains and might have a key role in the folding process.
Received 1 February 2001; accepted 7 February 2001 相似文献
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The article addresses the topic of the growth of mathematical knowledge with a special focus on the question: How are mathematical objects introduced to mathematical practice? It takes as starting point a proposal made in a previous paper which is based on a case study on the introduction of Riemann surfaces. The claim is that (i) a new object first refers to previously accepted objects, and that (ii) reasoning is possible via a correspondence to the objects with reference to which it is introduced. In addition Riemann surfaces are geometrical objects, i.e., they are placed in a geometrical context, which makes new definitions possible. This proposal is tested on a case study on Minkowski’s introduction of convex bodies. The conclusion is that the proposal holds also for this example. In both cases we notice that in a first stage is a close connection between the new object and the objects it is introduced with reference to, and that in a later stage, the new object is given an independent definition. Even though the two cases display similarity in these respects, we also point to certain differences between the cases in the process of the first stage. Overall we notice the fruitfulness of representing problems in different contexts. 相似文献
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F. V. De Feudis P. Madtes A. Ojeda M. Gadea-Ciria 《Cellular and molecular life sciences : CMLS》1976,32(8):1014-1015
The order of potency of binding of both glutamate and aspartate to synaptosomal fractions of brain regions was: cerebellar cortex caudate nucleus cerebral cortex > medulla pons > corona radiata. Glutamate was bound to a greater extent than aspartate to particles of all regions studied, except for cerebral cortex. 相似文献
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H. J. Bestmann J. Erler O. Vostrowsky 《Cellular and molecular life sciences : CMLS》1988,44(9):797-799
Summary By means of closed-loop-stripping and subsequent GC analyses the diel periodicity of release of (Z)-11-hexadecenyl acetate, (E)-8-dodecenyl acetate, and (Z)-9-tetradecenyl acetate, the main constituents of the respective sex pheromone blends ofMamestra brassicae, Cryptophlebia leucotreta andSpodoptera sunia females, was determined.Pheromones, 64. For the 63rd contribution we have taken from: Szöcs, G., Toth, M., Bestmann, H. J., Vostrowsky, O., Heath, R. R., and Tumlinson, J. H., Z. Naturforsch.42c (1987) 165; Pheromones, 62: Bestmann et al.13. 相似文献