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501.
Despite remarkable efforts, it remains notoriously difficult to equip quantum theory with a coherent ontology. Hence, Healey (2017, 12) has recently suggested that “quantum theory has no physical ontology and states no facts about physical objects or events”, and Fuchs et al. (2014, 752) similarly hold that “quantum mechanics itself does not deal directly with the objective world”. While intriguing, these positions either raise the question of how talk of ‘physical reality’ can even remain meaningful, or they must ultimately embrace a hidden variables-view, in tension with their original project. I here offer a neo-Kantian alternative. In particular, I will show how constitutive elements in the sense of Reichenbach (1920) and Friedman (1999, 2001) can be identified within quantum theory, through considerations of symmetries that allow the constitution of a ‘quantum reality’, without invoking any notion of a radically mind-independent reality. The resulting conception will inherit elements from pragmatist and ‘QBist’ approaches, but also differ from them in crucial respects. Furthermore, going beyond the Friedmanian program, I will show how non-fundamental and approximate symmetries can be relevant for identifying constitutive principles. 相似文献
502.
Szade Agata Szade Krzysztof Mahdi Mahdi Józkowicz Alicja 《Cellular and molecular life sciences : CMLS》2021,78(10):4639-4651
Cellular and Molecular Life Sciences - Hematopoietic system transports all necessary nutrients to the whole organism and provides the immunological protection. Blood cells have high turnover,... 相似文献
503.
Structural,morphological, and optical properties of tin(Ⅳ) oxide nanoparticles synthesized using Camellia sinensis extract: a green approach
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Tin oxide (SnO2) nanoparticles were cost-effectively synthesized using nontoxic chemicals and green tea (Camellia sinensis) extract via a green synthesis method.The structural properties of the obtained nanoparticles were studied using X-ray diffraction,which indicated that the crystallite size was less than 20 nm.The particle size and morphology of the nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy.The morphological analysis revealed agglomerated spherical nanoparticles with sizes varying from 5 to 30 nm.The optical properties of the nanoparticles' band gap were characterized using diffuse reflectance spectroscopy.The band gap was found to decrease with increasing annealing temperature.The O vacancy defects were analyzed using photoluminescence spectroscopy.The increase in the crystallite size,decreasing band gap,and the increasing intensities of the UV and visible emission peaks indicated that the green-synthesized SnO2 may play future important roles in catalysis and optoelectronic devices. 相似文献
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Julhash U. Kazi Rohit A. Chougule Tianfeng Li Xianwei Su Sausan A. Moharram Kaja Rupar Alissa Marhäll Mohiuddin Gazi Jianmin Sun Hui Zhao Lars Rönnstrand 《Cellular and molecular life sciences : CMLS》2017,74(14):2679-2688
The type III receptor tyrosine kinase FLT3 is frequently mutated in acute myeloid leukemia. Oncogenic FLT3 mutants display constitutive activity leading to aberrant cell proliferation and survival. Phosphorylation on several critical tyrosine residues is known to be essential for FLT3 signaling. Among these tyrosine residues, Y842 is located in the so-called activation loop. The position of this tyrosine residue is well conserved in all receptor tyrosine kinases. It has been reported that phosphorylation of the activation loop tyrosine is critical for catalytic activity for some but not all receptor tyrosine kinases. The role of Y842 residue in FLT3 signaling has not yet been studied. In this report, we show that Y842 is not important for FLT3 activation or ubiquitination but plays a critical role in regulating signaling downstream of the receptor as well as controlling receptor stability. We found that mutation of Y842 in the FLT3-ITD oncogenic mutant background reduced cell viability and increased apoptosis. Furthermore, the introduction of the Y842 mutation in the FLT3-ITD background led to a dramatic reduction in in vitro colony forming capacity. Additionally, mice injected with cells expressing FLT3-ITD/Y842F displayed a significant delay in tumor formation, compared to FLT3-ITD expressing cells. Microarray analysis comparing gene expression regulated by FLT3-ITD versus FLT3-ITD/Y842F demonstrated that mutation of Y842 causes suppression of anti-apoptotic genes. Furthermore, we showed that cells expressing FLT3-ITD/Y842F display impaired activity of the RAS/ERK pathway due to reduced interaction between FLT3 and SHP2 leading to reduced SHP2 activation. Thus, we suggest that Y842 is critical for FLT3-mediated RAS/ERK signaling and cellular transformation. 相似文献
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The aim of this study was to determine the structural, compositional, and mineralogical composition of carbonatitic copper sulfide concentrator plant streams. Three samples, each from a different stream(run of mine(ROM), concentrate, and tailings) of a copper concentrator were characterized using various techniques, including stereomicroscopy, X-ray fluorescence, X-ray diffraction, Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy(SEM) in conjunction with energy-dispersive X-ray spectroscopy(EDS), and optical microscopy. The results reveal that each stream possesses its own unique compositional features. Carbonate minerals associated with calcite and dolomite, followed by quartz, remain the major minerals in both the ROM and tails streams. In the ROM stream, chalcopyrite appears to occur as veins within the carbonatite-hosting ore body. Mineral phase mutation was discovered in the tails stream because magnetite formerly identified in the ROM as the primary iron oxide had evolved into hematite. This metamorphosis was likely promoted by the concentration process. The concentration process was effective, upgrading the chalcopyrite content from 2 wt% in the ROM stream to 58 wt% in the concentrate stream; it was accompanied by bornite(4 wt%), anilite(3 wt%), and digenite(2.5 wt%). In addition, the concentrate stream exhibited properties distinctive from those of the other streams. The FTIR analysis showed the existence of a sulfide group related to the chalcopyrite mineral. Free chalcopyrite grains were observed in the concentrate by SEM analysis, and their mineral presence was supported by the EDS analysis results. All characterization techniques corresponded well with each other regarding the structure, chemistry, and composition of the samples. 相似文献
507.
J. L. Heilbron 《Annals of science》2019,76(3-4):387-389
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