The exceptional properties of graphene originate from its two-dimensional polymeric structure of sp2-bonded carbon. This feature also causes graphene to grow on metal substrates through mechanisms ...that are strikingly different from those of conventional heteroepitaxy. We provide here a brief review of graphene growth on metals, a subject with a rich history even before the recent explosion of interest in graphene. The current activities related to graphene growth on metals have been motivated by the need to develop low-cost, scalable processes for graphene synthesis and to understand how graphene–metal interfaces behave in devices. In this article, we examine the current state of the art, emphasizing the basic processes that distinguish graphene growth from normal crystal growth.
Photoelectron spectroscopic measurements have the potential to provide detailed mechanistic insight by resolving chemical states, electrochemically active regions and local potentials or potential ...losses in operating solid oxide electrochemical cells (SOCs), such as fuel cells. However, high-vacuum requirements have limited X-ray photoelectron spectroscopy (XPS) analysis of electrochemical cells to ex situ investigations. Using a combination of ambient-pressure XPS and CeO(2-x)/YSZ/Pt single-chamber cells, we carry out in situ spectroscopy to probe oxidation states of all exposed surfaces in operational SOCs at 750 °C in 1 mbar reactant gases H(2) and H(2)O. Kinetic energy shifts of core-level photoelectron spectra provide a direct measure of the local surface potentials and a basis for calculating local overpotentials across exposed interfaces. The mixed ionic/electronic conducting CeO(2-x) electrodes undergo Ce(3+)/Ce(4+) oxidation-reduction changes with applied bias. The simultaneous measurements of local surface Ce oxidation states and electric potentials reveal the active ceria regions during H(2) electro-oxidation and H(2)O electrolysis. The active regions extend ~150 μm from the current collectors and are not limited by the three-phase-boundary interfaces associated with other SOC materials. The persistence of the Ce(3+)/Ce(4+) shifts in the ~150 μm active region suggests that the surface reaction kinetics and lateral electron transport on the thin ceria electrodes are co-limiting processes.
Emotional contagion – the transfer of emotions between people – is thought to occur automatically. We test the prediction, based on evolutionary psychology, that negative, threat‐related emotions ...transfer more automatically than positive emotions. We introduce a new paradigm for investigating emotional contagion where participants are exposed to videos of faces that morph from neutral to angry or happy expressions. Participants watched these videos under high or low cognitive load. Participants reported more happiness in the happy condition than the anger condition and more anger in the anger condition than the happy condition, supporting our new paradigm. Participants in the happy condition were significantly happier under low compared with high load. Participants were equally angry in high and low load conditions.
The objective was to determine the effects of maternal nutrient restriction during gestation on serum microRNA (miRNA) abundance in cattle. Primiparous Angus-cross cows (n=22) were fed either control ...(CON; to gain 1 Kg/week) or nutrient restricted (NR; 0.55% NEm) diets based on National Research Council requirements. On day 30 of gestation, cows were blocked by body condition and randomly assigned to one of three diets: CON (n=8) days 30–190; NR (n=7) days 30–110 followed by CON days 110–190 (NR/C); or CON (n=7) days 30–110 followed by NR days 110–190 (C/NR). At 190 days of gestation, maternal serum was collected for RNA isolation and analyzed using a miRNA microarray of known Bos taurus sequences. Data were normalized using LOWESS and analyzed via ANOVA. At 190 days of gestation, 16 miRNAs exhibited differential abundance (P<0.05) between treatments. Cows that underwent NR, irrespective of when the insult occurred, had downregulated bta-miR-126–3p compared to CON cows. Bta-miR-16b was downregulated and three miRNAs upregulated in NR/C compared to C/NR and CON cows. Additionally, seven miRNAs were downregulated and four miRNAs upregulated in C/NR compared to NR/C and CON cows. Comparison of NR/C and C/NR cows revealed three differentially abundant (P<0.04) miRNAs (bta-miR-2487_L-2R-3_1ss15CT, bta-miR-215, and bta-miR-760–5p). Top KEGG pathway enrichment of target genes included: pathways in cancer, PI3K-Akt signaling, focal adhesion, Ras signaling, proteoglycans in cancer, and MAPK signaling. In summary, maternal nutrient restriction altered serum miRNA abundance profiles irrespective of the time at which the nutritional insult was induced.
•Nutrient restriction altered serum miRNA abundance irrespective of time of insult.•Maternal serum at 190 days of gestation have 16 microRNAs of differential abundance.•The 16 miRNAs of interest are predicted to target a total of 7,576 genes.•Pathway analysis revealed a total of 106 enriched KEGG pathways.•Top three pathways: pathways in cancer, PI3K-Akt signaling, and focal adhesion.
Several finely dispersed low-temperature dioctahedral micas and micaceous minerals that form solid solutions from (Mg, Fe)-free illite to aluminoceladonite via Mg-rich illite, and from Fe3+-rich ...glauconite to celadonite have been studied by X-ray diffraction and chemical analysis. The samples have 1M and 1Md structures. The transitions from illite to aluminoceladonite and from glauconite to celadonite are accompanied by a consistent decrease in the mica structural-unit thickness (2:1 layer + interlayer) or csinβ. In the first sample series csinβ decreases from 10.024 to 9.898 Å, and in the second from 10.002 to 9.961 Å. To reveal the basic factors responsible for these regularities, structural modeling was carried out to deduce atomic coordinates for 1M dioctahedral mica based on the unit-cell parameters and cation composition. For each sample series, the relationships among csinβ, maximum and mean thicknesses of octahedral and tetrahedral sheets and of the 2:1 layer, interlayer distance, and variations of the tetrahedral rotation angle, α, and the degree of basal surface corrugation, ΔZ, have been analyzed in detail. The transitions from illite to aluminoceladonite and from glauconite to celadonite are accompanied by a slight increase in the mean thickness of the 2:1 layers and a steady decrease in the α angles, whereas the interlayer distance becomes smaller. These results are consistent with the generally accepted model where tetrahedral rotation is the main factor for the interlayer contraction in muscovite-phengite structures: the smaller the rotation angle (α) the larger the ditrigonal ring of the tetrahedral sheet and the interlayer pseudo-hexagonal cavity, allowing the interlayer cation to sink and thus shorten the c parameter. A new insight into the interpretation of the contraction of the mica layer thickness in dioctahedral micas has been achieved with the discovery that micas with the same or close mean interlayer distance, on one hand, have the same or nearly the same substitution of Al for Si; and on the other hand, they may have significantly different parameters of the interlayer structure, such as tetrahedral rotation, basal surface corrugation, ΔZ, and minimum and maximum interlayer distance. These results show that in dioctahedral 1M micas, the mean interlayer distance is determined by the amount of tetrahedral Al because the higher the Al for Si substitution, the stronger the repulsion between the basal O atoms and the larger the interlayer distance and csinβ parameter.
Friendship networks are instrumental to a whole range of outcomes including career success and personal wellbeing, and as such it is important to ask how social networks are shaped by personality ...variables. However, previous research examining how extraversion is associated with social network size and closeness to social network members has produced inconsistent findings. Here, we assessed how extraversion (HEXACO model) was associated with three key features of advice networks (size, density, and emotional closeness to network members) in a sample of 199 participants (17–75 years, M = 25, SD = 11; 146 women). We found that higher levels of extraversion (and its four facets: social self-esteem, social boldness, sociability, and liveliness) corresponded to a significantly larger advice network, but not greater network density, or greater emotional closeness to network members. The social manifestation of extraversion here seems to be operationalised in terms of a greater number of interactive advice partners, but no increased probability of ensuring that contacts are connected to each other, or of developing emotionally deep relationships with contacts.
The current study explored how social media can satisfy unmet needs for belonging. We predicted that, of those who experience chronic ostracism (feeling excluded and ignored frequently), people high ...in need to belong would utilize Twitter to satisfy their unmet belonging needs more than those low in need to belong. Specifically, individuals high in need to belong and chronic ostracism should use Twitter to form and maintain parasocial relationships (one-sided relationships with media figures). Participants (n = 315) completed a survey assessing their chronic ostracism experiences, dispositional need to belong, and Twitter behavior, particularly regarding potential parasocial relationship targets (n = 229). As expected, when participants reported experiencing high rates of chronic ostracism, participants high in need to belong used Twitter more than those low in need to belong, particularly following more parasocial relationship targets. Thus, maintaining parasocial relationships on Twitter may be an effective way to satisfy unmet belonging needs.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The objective of this study was to determine effects of maternal nutrient restriction (NR) during early or mid-gestation on uterine composition and miRNA expression in cotyledons. Primiparous ...Angus-cross cows (n = 38) were synchronized and inseminated using male sexed semen, blocked by body condition score and body weight (BW), and assigned to treatments. Animals were fed either: control (CON; gain 1 kg/week) or NR (55% maintenance energy and crude protein requirements) based on BW. An initial set of animals were fed either NR (n = 8) or CON (n = 8) from day 30–110 of gestation. A second set of animals were fed CON (n = 8) d 30–190 (CON/CON); NR (n = 7) day 30–110 followed by CON day 110–190 (NR/CON); or CON (n = 7) day 30–110 followed by NR day 110–190 (CON/NR). Cows were harvested on day 110 or 190 of gestation to collect placental tissues. RNA was isolated from cotyledon samples (3 animals/group) prior to microarray analysis using known Bos taurus microRNA sequences. Relative microRNA abundance was analyzed via ANOVA. Maternal NR increased (P < 0.05) cotyledon weight and total placentome surface area irrespective of gestational day. At day 110 of gestation, 51 microRNAs were reduced while 91 microRNAs observed greater abundance (P < 0.05) in NR verses CON cotyledons. At day 190 of gestation, 40 microRNAs were reduced and 26 microRNAs were increased (P < 0.05) in both NR/CON and CON/NR verses CON cotyledons. Top KEGG pathway analysis included: axon guidance, endocytosis, neuroactive ligand receptor interaction, and MAPK signaling pathway. Early-gestation maternal NR altered microRNA abundance to a greater extent than mid-gestation NR.
•Maternal NR increased cotyledon weight and total placentome SA irrespective of time of restriction.•In gestation day 110 cotyledons, 51 microRNAs were reduced and 91 microRNAs were increased in NR verses CON.•In gestation day 190 cotyledons, 40 microRNAs were reduced and 26 microRNAs were increased in both NR verses CON.•Early-gestation maternal NR altered microRNA abundance to a greater extent than late gestation NR.
The reflectivity of low-energy electrons from graphene on copper substrates is studied both experimentally and theoretically. Well-known oscillations in the reflectivity of electrons with energies ...0-8 eV above the vacuum level are observed in the experiment. These oscillations are reproduced in theory, based on a first-principles density functional description of interlayer states forming for various thicknesses of multilayer graphene. It is demonstrated that n layers of graphene produce a regular series of n - 1 minima in the reflectance spectra, together with a possible additional minimum associated with an interlayer state forming between the graphene and the substrate. Both (111) and (001) orientations of the copper substrates are studied. Similarities in their reflectivity spectra arise from the interlayer states, whereas differences are found because of the different Cu band structures along those orientations. Results for graphene on other substrates, including Pt(111) and Ir(111), are also discussed.
PDF
