Understanding Actinides through the Role of 5f Electrons

MRS Bulletin ◽  
2001 ◽  
Vol 26 (9) ◽  
pp. 684-688 ◽  
Author(s):  
T. Gouder ◽  
F. Wastin ◽  
J. Rebizant ◽  
G.H. Lander

Studies of the actinide elements and compounds were (and are) motivated by the need to characterize their structural and thermodynamic properties for the development of nuclear fuels and the treatment of waste, whether it be for long-term storage or ideas involving transmutation in high-powered accelerators. For the most part, tables giving these data exist, although the data for transuranium compounds are rather sparse. A much more difficult task is to understand the data and develop theories that have predictive power in this part of the periodic table. In doing this, however, we are confronted with the extremely complicated electronic structure of the 5f shell and the great paucity of high-quality data on materials containing transuranium isotopes.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Grzegorz Leśnierowski ◽  
Tianyu Yang ◽  
Renata Cegielska-Radziejewska

AbstractThermal modification is an effective method that induces significant expansion of the antimicrobial properties and other valuable properties of chicken egg white lysozyme. In our latest research, a new innovative method of enzyme modification was developed, in which microwave radiation was used as an energy source to process liquid lysozyme concentrate (LLC). After modification, high-quality preparations were obtained. However, long-term storage in a concentrated form initiated various processes that caused darkening over time and could also lead to other significant changes to their structure and, consequently, to their functional properties. This necessitated multidirectional research to explain this phenomenon. This paper presents the results of research aimed at assessing the physicochemical changes in the properties of microwave-modified lysozyme in the form of a liquid concentrate after long-term storage under refrigeration conditions. The assessment also considered the conditions under the acidity of the modifying medium and the duration of the microwave modification. The analysis showed that the values of the basic parameters determining the quality and usefulness of the modified enzyme significantly improved during long-term storage of the preparations. The greatest changes were observed in the preparations modified for the longest time and in the most acidic environment (process time 260 s, pH 2.0), the number of oligomers under these conditions increased by 18% after 12 months of holding, and the surface hydrophobicity increased by as much as 31%. In addition, microbiological tests showed that the preparations of microwave-modified lysozyme had an effect on gram-positive bacteria as well as on gram-negative, and this effect was significantly enhanced after 12 months. The results confirm that LLC modification with microwave radiation is a highly efficient method to prepare high-quality and high utility potential lysozyme. Notably, an interesting and important phenomenon was the observation of the unconventional behaviour of the preparations during their long-term storage, which increased their utility potential significantly.


2010 ◽  
Vol 16 (4) ◽  
pp. 343-350 ◽  
Author(s):  
M. Guerra ◽  
P.A. Casquero

Two strategies, summer pruning and postharvest Ca treatment, were studied in apple (Malus domestica Borkh) cv. ‘Reinette du Canada’ in order to analyze its effect on the fruit quality during storage. Summer pruning and Ca treatment reduced external and internal bitter-pits; so after 180 days of storage, both treatments decreased external bitter-pit by 10.0% and 16.7%, respectively. Summer pruning influenced color, firmness, total soluble solids and titratable acidity (TA) of fruit during storage, whereas Ca treatment only affected firmness and TA. Fruit from pruned trees had significant lower K and Mg than those from unpruned trees and Ca treatment increased Ca content. Orchard management, by means of summer pruning, combined with Ca postharvest application would be useful to prevent losses due to bitter-pit during storage in commercial orchards. However, in organic orchards, summer pruning would be the ecological alternative to decrease bitter-pit incidence during storage in high quality apple cv. ‘Reinette du Canada’. K/Ca ratio, on the peel at harvest, turned out to be the best parameter to correlate with external and internal bitter-pits during storage; so this ratio would be useful to predict bitter-pit on long-term storage.


2017 ◽  
Vol 86 (4) ◽  
Author(s):  
Ewelina Ratajczak ◽  
Karl Josef Dietz

Peroxiredoxins (Prx) are important regulators of the redox status of tree seeds during maturation and long-term storage. Thioredoxins (Trx) are redox transmitters and thereby regulate Prx activity. Current research is focused on the association of Trx with Prx in tree seeds differing in the tolerance to desiccation. The results will allow for better understanding the regulation of the redox status in orthodox, recalcitrant, and intermediate seeds. The findings will also elucidate the role of the redox status during the loss of viability of sensitive seeds during drying and long-term storage.


Metabolites ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 93 ◽  
Author(s):  
Cora McHugh ◽  
Thomas Flott ◽  
Casey Schooff ◽  
Zyad Smiley ◽  
Michael Puskarich ◽  
...  

Background: Though blood is an excellent biofluid for metabolomics, proteins and lipids present in blood can interfere with 1d-1H NMR spectra and disrupt quantification of metabolites. Here, we present effective macromolecule removal strategies for serum and whole blood (WB) samples. Methods: A variety of macromolecule removal strategies were compared in both WB and serum, along with tests of ultrafiltration alone and in combination with precipitation methods. Results: In healthy human serum, methanol:chloroform:water extraction with ultrafiltration was compared to methanol precipitation with and without ultrafiltration. Methods were tested in healthy pooled human serum, and in serum from patients with sepsis. Effects of long-term storage at −80 °C were tested to explore the impact of macromolecule removal strategy on serum from different conditions. In WB a variety of extraction strategies were tested in two types of WB (from pigs and baboons) to examine the impact of macromolecule removal strategies on different samples. Conclusions: In healthy human serum methanol precipitation of serum with ultrafiltration was superior, but was similar in recovery and variance to methanol:chloroform:water extraction with ultrafiltration in pooled serum from patients with sepsis. In WB, high quality, quantifiable spectra were obtained with the use of a methanol: chloroform precipitation.


Author(s):  
Angela Seawright ◽  
Altug Ozcelikkale ◽  
J. Craig Dutton ◽  
Bumsoo Han

Cryopreservation can provide long-term storage of various biological tissues, which has significant impact on tissue engineering and regenerative medicine. For successful cryopreservation of tissues, tissue functionality must be maintained including physical properties such as mechanical, optical, and transport properties, as well as cellular viability. Such properties are associated with the extracellular matrix (ECM) microstructure. Thus, the preservation of the ECM microstructure may lead to successful cryopreservation [1,2]. Yet, there is still very little known about changes in the ECM microstructure during freezing/thawing.


2010 ◽  
Vol 33 (1) ◽  
pp. 28-29 ◽  
Author(s):  
Brad R. Huber

AbstractThis commentary suggests that there is more continuity in pre- and post-demographic transition populations with respect to grandparental investments than is assumed by Coall & Hertwig (C&H). Recent research employing high-quality data supports the claim that sex-biased grandparental investments are likely to exist in industrialized societies, and that the economic status of grandparents is related to their long-term fitness.


1985 ◽  
Vol 16 (2) ◽  
pp. 89-104 ◽  
Author(s):  
S. Bergström ◽  
B. Carlsson ◽  
G. Sandberg ◽  
L. Maxe

Based on the experience from runoff and groundwater recharge simulation a model system has been developed for terrestrial, hydrochemical, and hydrological simulations. The system emphasizes the role of temporary or long term storage in the aquifers of a basin and, separately, accounts for each rainfall or snowmelt event from its entrance into the ground until mixing in the river system. The model is primarily intended for simulation of natural short term variations in alkalinity and pH in running waters. The hydrochemical processes are modelled in a semi-empirical way without assumption of complete hydrochemichal mass-balance. In the paper a brief hydrochemical background is given, and a model with two alternative hydrochemical sub-structures is described. Examples of daily simulations of runoff alkalinity and pH from three different basins are given.


2016 ◽  
Vol 87 (3) ◽  
pp. 191-204 ◽  
Author(s):  
Carolyn L. Pytte

Our understanding of the role of new neurons in learning and encoding new information has been largely based on studies of new neurons in the mammalian dentate gyrus and olfactory bulb - brain regions that may be specialized for learning. Thus the role of new neurons in regions that serve other functions has yet to be fully explored. The song system provides a model for studying new neuron function in brain regions that contribute differently to song learning, song auditory discrimination, and song motor production. These regions subserve learning as well as long-term storage of previously learned information. This review examines the differences between learning-based and activity-based retention of new neurons and explores the potential contributions of new neurons to behavioral stability in the song motor production pathway.


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