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61.
V. Zimmitti E. Benedetti V. Caracciolo P. Sebastiani S. Di Loreto 《Microgravity science and technology》2010,22(1):37-43
Altered gravity forces might influence neuroplasticity and can provoke changes in biochemical mechanisms. In this contest,
neurotrophins have a pivotal role, particularly nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF). A
suspension of dissociated cortical cells from rat embryos was exposed to 24 h of microgravity before plating in normal adherent
culture system. Expression and transductional signalling pathways of NGF and BDNF were assessed at the end of maturational
process (8–10 days in vitro). Rotating wall vessel bioreactor (RWV) pre-exposition did not induce changes in NGF expression
and its high affinity receptor TrkA. On the contrary both BDNF expression and its high affinity receptor TrkB were strongly
up-regulated, inducing Erk-5, but not Erk-1/2 activation and, in turn, MEF2C over-expression and activation. According to
our previous and present results, we postulate that relatively short microgravitational stimuli, applied to neural cells during
the developmental stage, exert a long time activation of specific neurotrophic pathways. 相似文献
62.
63.
Evaluation of the Feasibility of Irrigation Storage in a Flood Detention Pond in an Agricultural Catchment in Northern Italy 总被引:3,自引:2,他引:1
During recent years, the international attention paid to rational use and saving of water has increased, partly because of
frequent water shortages occurring also in countries not usually involved in these problems, and partly as a consequence of
rising conflicts on water allocation. Hence it is important to find new surface-water volumes satisfying agricultural water
demand, as well as new ways and areas to store them. The simulation model presented by the paper enables evaluation, in a
phase of design feasibility analysis, of whether a flood detention pond can be adapted to act as water storage during irrigation
periods in order to reduce agricultural water shortages; it simulates detention pond response to floods and droughts under
different hydraulic conditions and reservoir management rules. The first policy goal of the model is to maintain the stored
volume within the maximum admissible for flood safety. The second goal is to maintain at the same time a minimum flow in the
river and to satisfy irrigation water demand. The model, implemented in a purpose-made simulation software, was applied to
an Italian river in the Emilia Romagna region: the results demonstrate that the use of a flood detention pond as an irrigation
reservoir is not only possible, if it complies with the operating rules that emerge from this study, but also it brings tangible
benefits in reducing agricultural water deficit. 相似文献
64.
S. K. Varma Erica Corral Erika Esquivel Daniel Salas 《Metallurgical and Materials Transactions A》1999,30(9):2539-2545
A solutionizing heat treatment of 2014 aluminum alloy reinforced with 0.15 volume fraction of alumina particles (VFAP) results
in deformation-induced precipitation during rolling and tensile deformation, with 0.10 VFAP, at room temperature. The extent
of precipitation increases with increase in time and/or temperature of solutionizing. An attempt has been made to identify
the various types of precipitates in the samples deformed to a given strain and in fractured conditions. The work-hardening
curves and tensile properties of the composites have been shown to be dependent on the time and temperature combination of
the solutionizing process. 相似文献
65.
66.
Erica Bazzan Mariaenrica Tin Alvise Casara Davide Biondini Umberto Semenzato Elisabetta Cocconcelli Elisabetta Balestro Marco Damin Claudia Maria Radu Graziella Turato Simonetta Baraldo Paolo Simioni Paolo Spagnolo Marina Saetta Manuel G. Cosio 《International journal of molecular sciences》2021,22(12)
Extracellular vesicles (EVs) are a family of particles/vesicles present in blood and body fluids, composed of phospholipid bilayers that carry a variety of molecules that can mediate cell communication, modulating crucial cell processes such as homeostasis, induction/dampening of inflammation, and promotion of repair. Their existence, initially suspected in 1946 and confirmed in 1967, spurred a sharp increase in the number of scientific publications. Paradoxically, the increasing interest for EV content and function progressively reduced the relevance for a precise nomenclature in classifying EVs, therefore leading to a confusing scientific production. The aim of this review was to analyze the evolution of the progress in the knowledge and definition of EVs over the years, with an overview of the methodologies used for the identification of the vesicles, their cell of origin, and the detection of their cargo. The MISEV 2018 guidelines for the proper recognition nomenclature and ways to study EVs are summarized. The review finishes with a “more questions than answers” chapter, in which some of the problems we still face to fully understand the EV function and potential as a diagnostic and therapeutic tool are analyzed. 相似文献
67.
The yeast retrotransposon Ty5 preferentially integrates into regions of silent chromatin. Ty5 cDNA also recombines with homologous sequences, generating tandem elements or elements that have exchanged markers between cDNA and substrate. In this study, we demonstrate that Ty5 integration depends upon the conserved DD(35)E domain of integrase and cis-acting sequences at the end of the long terminal repeat (LTR) implicated in integrase binding. cDNA recombination requires Rad52p, which is responsible for homologous recombination. Interestingly, Ty5 cDNA recombines at least three times more frequently with substrates in silent chromatin than with a control substrate at an internal chromosomal locus. This preference depends upon the Ty5 targeting domain that is responsible for integration specificity, suggesting that localization of cDNA to silent chromatin results in the enhanced recombination. Recombination with a telomeric substrate occasionally generates highly reiterated Ty5 arrays, and mechanisms for tandem element formation were explored by using a plasmid-based recombination assay. Point mutations were introduced into plasmid targets, and recombination products were characterized to determine recombination initiation sites. Despite our previous observation of the importance of the LTR in forming tandem elements, recombination cannot simply be explained by crossover events between the LTRs of substrate and cDNA. We propose an alternative model based on single-strand annealing, where single-stranded cDNA initiates tandem element formation and the LTR is required for strand displacement to form a looped intermediate. Retrotransposons are increasingly found associated with chromosome ends, and amplification of Ty5 by both integration and recombination exemplifies how retroelements can contribute to telomere dynamics. 相似文献
68.
69.
Behrend Douglas A.; Scofield Jason; Kleinknecht Erica E. 《Canadian Metallurgical Quarterly》2001,37(5):698
L. Markson and P. Bloom (1997) concluded that there was evidence against a dedicated system for word learning on the basis of their finding that children remembered a novel word and a novel fact equally well. However, a word-learning system involves more than recognition memory; it must also provide a means to guide the extension of words to additional exemplars, and words and facts may differ with regard to extendibility. Two studies are reported in which 2–4-year-old children learned novel words and novel facts for unfamiliar objects and then were asked to extend the words and facts to additional exemplars of the training objects. In both studies, children extended the novel word to significantly more category members than they extended the novel fact. The results show that by 2 years of age, children honor the necessary extendibility of novel count nouns but are uncertain about the extendibility of arbitrary facts. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.
Patrick L Jacobs Erica R Goldstein Will Blackburn Ihsan Orem John J Hughes 《Journal of the International Society of Sports Nutrition》2009,6(1):9-11