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排序方式: 共有177条查询结果,搜索用时 15 毫秒
121.
Dmitri Kalaev Thomas Defferriere Clement Nicollet Tamar Kadosh Harry L. Tuller 《Advanced functional materials》2020,30(11)
Solid‐state mixed ionic–electronic conductors (MIECs) in which ionic transport is commonly accompanied by predominant electronic conductivity underpin key technologies and require universal characterization methods for monitoring transport at the nanoscale, at both high and near ambient temperatures, the latter being especially challenging. In this study, a novel dynamic current–voltage analysis technique is utilized to decouple ionic and electronic transport properties from each other. The versatility of the method is demonstrated by enabling measurement of the oxygen vacancy mobility in Pr0.1Ce0.9O2?δ thin films, across an unusually wide temperature range, from 35 to 500 °C. Despite the presence of predominant electronic conduction, the oxygen vacancy mobility in Pr0.1Ce0.9O2?δ is measured, being 6.8 × 10?6 cm2 V?1 s?1 at 500 °C, decreasing by seven orders of magnitude down to 35 °C, and following a single thermal activation energy of 0.82 ± 0.02 eV. A comparison with previous reports on oxygen vacancy transport and with the one derived in this study from impedance spectroscopy, interpreted with the Jamnik–Maier model, further confirms the dynamic current–voltage analysis results. This method can more generally be applied to other types of MIECs, thereby enabling deeper insights into mobile ionic defect transport and accompanying thermodynamic properties. 相似文献
122.
With 2 critical readings of William Wordsworth's "Ode: Intimations of Immortality From Recollections of Early Childhood," this article presents contrasting assumptions of the literary critic about the development of artistic creativity and relates them to the issue of continuity and change in literary expression over the life span. The unveiled assumptions parallel the "hard" (structuralist) and "soft" (life-span) conceptions of human development prevailing in contemporary psychology. A better understanding of creative development may be reached by superimposing the principles derived from the soft metatheoretical orientation on those of the hard theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
123.
Erez Shmueli Ronen Mansuri Matan Porcilan Tamar Amir Lior Yosha Matan Yechezkel Tal Patalon Sharon Handelman-Gotlib Sivan Gazit Dan Yamin 《Journal of the Royal Society Interface》2021,18(181)
Current COVID-19 screening efforts mainly rely on reported symptoms and the potential exposure to infected individuals. Here, we developed a machine-learning model for COVID-19 detection that uses four layers of information: (i) sociodemographic characteristics of the individual, (ii) spatio-temporal patterns of the disease, (iii) medical condition and general health consumption of the individual and (iv) information reported by the individual during the testing episode. We evaluated our model on 140 682 members of Maccabi Health Services who were tested for COVID-19 at least once between February and October 2020. These individuals underwent, in total, 264 516 COVID-19 PCR tests, out of which 16 512 were positive. Our multi-layer model obtained an area under the curve (AUC) of 81.6% when evaluated over all the individuals in the dataset, and an AUC of 72.8% when only individuals who did not report any symptom were included. Furthermore, considering only information collected before the testing episode—i.e. before the individual had the chance to report on any symptom—our model could reach a considerably high AUC of 79.5%. Our ability to predict early on the outcomes of COVID-19 tests is pivotal for breaking transmission chains, and can be used for a more efficient testing policy. 相似文献
124.
Maturity of technologies from one side and customers' demands from the other side have led to the need to develop increasingly large and complex systems. The problem we face is to structure the development of these types of systems and the systems themselves in a useful way and to support the development process from its conceptual foundation to its tool aspect.We believe that we must take one step beyond the current software engineering methodology to be able to cope with this task. What we propose is a framework, a meta-process model, that allows one to develop in a flexible but integrated manner a distributed, open, and integrated system with a planned approach. Based on the premise that the main factor is to build a common culture of understanding and conceptual thinking in an application domain, we suggest an additional level of coordination and modeling above the various development projects. In analyzing this two-leveled process model, we identify the major processes and models involved. While we focus on the process model itself, we discuss also in some more depth the two major concepts of domain analysis and integration architecture design as they relate to our approach. A strategy for realizing the meta-process model based on the notion of Application Machines is described. 相似文献
125.
Origin of defect-related green emission from ZnO nanoparticles: effect of surface modification 总被引:2,自引:0,他引:2
Yinyan Gong Tamar Andelman Gertrude F. Neumark Stephen O’Brien Igor L. Kuskovsky 《Nanoscale research letters》2007,2(6):297-302
We investigated the optical properties of colloidal-synthesized ZnO spherical nanoparticles prepared from 1-octadecene (OD),
a mixture of trioctylamine (TOA) and OD (1:10), and a mixture of trioctylphosphine oxide (TOPO) and OD (1:12). It is found
that the green photoluminescence (PL) of samples from the mixture of TOA/OD and TOPO/OD is largely suppressed compared with
that from pure OD. Moreover, it is found that all spherical nanoparticles have positive zeta potential, and spherical nanoparticles
from TOA/OD and TOPO/OD have a smaller zeta potential than those from OD. A plausible explanation is that oxygen vacancies,
presumably located near the surface, contribute to the green PL, and the introduction of TOA and TOPO will reduce the density
of oxygen vacancies near the surfaces. Assuming that the green emission arises due to radiative recombination between deep
levels formed by oxygen vacancies and free holes, we estimate the size of optically active spherical nanoparticles from the
spectral energy of the green luminescence. The results are in good agreement with results from TEM. Since this method is independent
of the degree of confinement, it has a great advantage in providing a simple and practical way to estimate the size of spherical
nanoparticles of any size. We would like to point out that this method is only applicable for samples with a small size distribution. 相似文献
126.
127.
OBJECTIVE: This research directly tests the relationship between comprehension probability of highway signs and the extent to which they comply with three ergonomic principles of design: sign-content compatibility, familiarity, and standardization. BACKGROUND: A recent study that evaluated comprehension of traffic signs in four different countries showed that comprehension level varies widely and is apparently related to the extent that the sign's design incorporates ergonomic guidelines for good design (D. Shinar, R. E. Dewar, H. Summala, and L. Zakowska 2003). METHOD: Participants were presented with 30 signs and asked to describe each sign's meaning. They then evaluated each sign in terms of each of three ergonomic principles. In addition, a group of human factors/ergonomics experts evaluated each sign on its standardization and compatibility. RESULTS: There were high correlations between the ratings of the students and the ratings of the experts on compatibility (rho = .94) and on standardization (rho = .84), validating the use of the students' evaluations of the signs on these variables. There was a great variability in signs' comprehension and high and statistically significant correlations between the comprehension level of each sign and the extent to which it complied with compatibility (R = .76), familiarity (R = .89), and standardization (R = .88) principles. CONCLUSIONS: The more signs conform to universal ergonomic principles of good design, the more likely they are to be comprehended by drivers of different cultural backgrounds. APPLICATION: Sign design should be guided by established ergonomics principles to enhance comprehension, especially for drivers who have not had any prior encounters with specific signs. 相似文献
128.
Daniel Laloum Sahar Magen Yoram Soroka Tamar Avin-Wittenberg 《International journal of molecular sciences》2022,23(7)
Autophagy is an essential intracellular eukaryotic recycling mechanism, functioning in, among others, carbon starvation. Surprisingly, although autophagy-deficient plants (atg mutants) are hypersensitive to carbon starvation, metabolic analysis revealed that they accumulate sugars under such conditions. In plants, sugars serve as both an energy source and as signaling molecules, affecting many developmental processes, including root and shoot formation. We thus set out to understand the interplay between autophagy and sucrose excess, comparing wild-type and atg mutant seedlings. The presented work showed that autophagy contributes to primary root elongation arrest under conditions of exogenous sucrose and glucose excess but not during fructose or mannitol treatment. Minor or no alterations in starch and primary metabolites were observed between atg mutants and wild-type plants, indicating that the sucrose response relates to its signaling and not its metabolic role. Extensive proteomic analysis of roots performed to further understand the mechanism found an accumulation of proteins essential for ROS reduction and auxin maintenance, which are necessary for root elongation, in atg plants under sucrose excess. The analysis also suggested mitochondrial and peroxisomal involvement in the autophagy-mediated sucrose response. This research increases our knowledge of the complex interplay between autophagy and sugar signaling in plants. 相似文献
129.
Omri Zveik Ariel Rechtman Nitzan Haham Irit Adini Tamar Canello Iris Lavon Livnat Brill Adi Vaknin-Dembinsky 《International journal of molecular sciences》2022,23(13)
Neuromyelitis optica (NMO) is a rare disease usually presenting with bilateral or unilateral optic neuritis with simultaneous or sequential transverse myelitis. Autoantibodies directed against aquaporin-4 (AQP4-IgG) are found in most patients. They are believed to cross the blood–brain barrier, target astrocytes, activate complement, and eventually lead to astrocyte destruction, demyelination, and axonal damage. However, it is still not clear what the primary pathological event is. We hypothesize that the interaction of AQP4-IgG and astrocytes leads to DNA damage and apoptosis. We studied the effect of sera from seropositive NMO patients and healthy controls (HCs) on astrocytes’ immune gene expression and viability. We found that sera from seropositive NMO patients led to higher expression of apoptosis-related genes, including BH3-interacting domain death agonist (BID), which is the most significant differentiating gene (p < 0.0001), and triggered more apoptosis in astrocytes compared to sera from HCs. Furthermore, NMO sera increased DNA damage and led to a higher expression of immunological genes that interact with BID (TLR4 and NOD-1). Our findings suggest that sera of seropositive NMO patients might cause astrocytic DNA damage and apoptosis. It may be one of the mechanisms implicated in the primary pathological event in NMO and provide new avenues for therapeutic intervention. 相似文献
130.
RNA motif classification is important for understanding structure/function connections and building phylogenetic relationships. Using our coarse-grained RNA-As-Graphs (RAG) representations, we identify recurrent dual graph motifs in experimentally solved RNA structures based on an improved search algorithm that finds and ranks independent RNA substructures. Our expanded list of 183 existing dual graph motifs reveals five common motifs found in transfer RNA, riboswitch, and ribosomal 5S RNA components. Moreover, we identify three motifs for available viral frameshifting RNA elements, suggesting a correlation between viral structural complexity and frameshifting efficiency. We further partition the RNA substructures into 1844 distinct submotifs, with pseudoknots and junctions retained intact. Common modules are internal loops and three-way junctions, and three submotifs are associated with riboswitches that bind nucleotides, ions, and signaling molecules. Together, our library of existing RNA motifs and submotifs adds to the growing universe of RNA modules, and provides a resource of structures and substructures for novel RNA design. 相似文献