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21.
Two consequences of coherence of mesonic fields have been tested in proton-nucleus collisions. Multiplicity fluctuations measured in finite rapidity intervals are found to obey a Poisson distribution at large rapidities where nuclear transparency occurs. In close analogy to quantum optics we present a quark-parton model in which this link between coherence and transparency is realized via the phenomenon of self-induced transparency. 相似文献
22.
Zusammenfassung Eines der wenigen Beispiele, bei denen in neuerer Zeit anomale Racemate beschrieben wurden, 1st die Äpfelsäure; sie diente als Studienobjekt.Eine Neubearbeitung des Phasendiagramms ergab, daß DL-Äpfelsäure dimorph ist und Mod. II als stabilisierte Zwischenphase auftritt, so daß in dem System D-Äpfelsäure-L-Äpfelsäure statt der bei Racematdiagrammen üblichen zwei Kristallphasen drei verschiedene Phasen vorliegen. Dadurch wird ein System mit einer homogen schmelzenden (normales Racemat) und zwei inhomogen schmelzenden Verbindungen (anomale Racemate) vorgetäuscht.Es wird die Meinung vertreten, daß keine anomalen Racemate existieren, sondern daß die vermeintlichen Anomalien bei enantiomeren Verbindungen ebenso wie bei anderen Zweistoffsystemen auf Polymorphie und Mischkristallbildung beruhen.
On the existence of anomalous racemates
Summary Malic acid is one of the few substances in which anomalous racemates have been recently described, and it was the object of this study. A new processing of the phase diagram revealed that DL malic acid is dimorphic and that Mod. II occurs as a stabilized intermediate phase. Instead of the two crystal phases usual in the racemate diagram, three different phases are present in the system D malic acid-L malic acid. A system is thereby simulated with a homogenously melting (normal racemate) and two inhomogenously melting compounds (anomalous racemates).The opinion is expressed that no anomalous racemates exist, but that the supposed anomalies in enantiomeric substances as in other twosubstance systems are based on polymorphism and formation of mixed crystals.相似文献
23.
E. Balea E. M. Friedländer C. Potoceanu M. Sahini 《Proceedings Mathematical Sciences》1962,55(6):367-392
A statistical method is developed for analyzing the angular distribution of meson jets produced by heavy primary cosmic-ray nuclei, enabling detection and elimination of the proton jet due to evaporation of the residual incident nucleus. The procedure is applied to 50 high-energy collisions of heavy primary nuclei. It is shown that a significant fraction of the heavy primaries produce bi-modal meson jets consistent with the two-centre model. 相似文献
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25.
Encapsulation-dehydration was applied to cryopreserve 14 diverse algal strains, representing eukaryotic terrestrial microalgae; of these 12 survived to form cell colonies after recovery from cryostorage. Surviving algae had varying degrees of tolerance to osmotic dehydration and desiccation in this vitrification-based cryoprotective strategy. The extent of algal regrowth was affected by the mode of desiccation (silica gel or air-flow), the duration of evaporative desiccation and exposure to light during early recovery phase. This paper: (i) demonstrates the versatility of the encapsulation/dehydration method to cryopreserve diverse microalgae; (ii) confirms the successful transfer of this cryostorage technology to the Culture Collection of Algae at Gottingen University (SAG); and (iii) recommends encapsulation/dehydration as a feasible alternative to controlled rate cooling for preserving algae held in international culture collections. 相似文献
26.
Renata Monteiro-Maia Maria B Ortigão-de-Sampaio Rosa T Pinho Luiz RR Castello-Branco 《Journal of immune based therapies and vaccines》2006,4(1):1-6
We hypothesize that the energy strategy of a cell is a key factor for determining how, or if, the immune system interacts
with that cell. Cells have a limited number of metabolic states, in part, depending on the type of fuels the cell consumes.
Cellular fuels include glucose (carbohydrates), lipids (fats), and proteins. We propose that the cell's ability to switch
to, and efficiently use, fat for fuel confers immune privilege. Additionally, because uncoupling proteins are involved in
the fat burning process and reportedly in protection from free radicals, we hypothesize that uncoupling proteins play an important
role in immune privilege. Thus, changes in metabolism (caused by oxidative stresses, fuel availability, age, hormones, radiation,
or drugs) will dictate and initiate changes in immune recognition and in the nature of the immune response. This has profound
implications for controlling the symptoms of autoimmune diseases, for preventing graft rejection, and for targeting tumor
cells for destruction. 相似文献
27.
28.
A. Tschirch H. Rosenthal G. Friedl?nder und W. Schneiter 《Fresenius' Journal of Analytical Chemistry》1929,76(7-8):312-314
Ohne Zusammenfassung 相似文献
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30.
The chemical state of gold adsorbed on activated carbon from solutions of KAu(CN)2 has been studied by197Au Mössbauer spectroscopy as a function of the pH and concentration of the solution, the loading of the carbon, and the drying conditions of the samples. On freshly prepared specimens Au(CN) 2 ? is always the dominant species. Drying leads to the formation of other forms of gold, mainly in samples loaded from strongly acidic media. An oligomeric form of AuCN is, however, also formed when samples loaded at high pH values are dried at temperatures around 100°C. 相似文献