260 research outputs found
Long Days Enhance Recognition Memory and Increase Insulin-like Growth Factor 2 in the Hippocampus
Light improves cognitive function in humans; however, the neurobiological mechanisms underlying positive effects of light remain unclear. One obstacle is that most rodent models have employed lighting conditions that cause cognitive deficits rather than improvements. Here we have developed a mouse model where light improves cognitive function, which provides insight into mechanisms underlying positive effects of light. To increase light exposure without eliminating daily rhythms, we exposed mice to either a standard photoperiod or a long day photoperiod. Long days enhanced long-term recognition memory, and this effect was abolished by loss of the photopigment melanopsin. Further, long days markedly altered hippocampal clock function and elevated transcription of Insulin-like Growth Factor2 (Igf2). Up-regulation of Igf2 occurred in tandem with suppression of its transcriptional repressor Wilmâs tumor1. Consistent with molecular de-repression of Igf2, IGF2 expression was increased in the hippocampus before and after memory training. Lastly, long days occluded IGF2-induced improvements in recognition memory. Collectively, these results suggest that light changes hippocampal clock function to alter memory, highlighting novel mechanisms that may contribute to the positive effects of light. Furthermore, this study provides insight into how the circadian clock can regulate hippocampus-dependent learning by controlling molecular processes required for memory consolidation
High Entropy Rare Earth A2b2o7 Type Zirconates
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Percolation of Ion-Irradiation-Induced Disorder in Complex Oxide Interfaces
Mastery of order-disorder processes in highly non-equilibrium nanostructured
oxides has significant implications for the development of emerging energy
technologies. However, we are presently limited in our ability to quantify and
harness these processes at high spatial, chemical, and temporal resolution,
particularly in extreme environments. Here we describe the percolation of
disorder at the model oxide interface LaMnO / SrTiO, which we visualize
during in situ ion irradiation in the transmission electron microscope. We
observe the formation of a network of disorder during the initial stages of ion
irradiation and track the global progression of the system to full disorder. We
couple these measurements with detailed structural and chemical probes,
examining possible underlying defect mechanisms responsible for this unique
percolative behavior.Comment: 32 pages, 14 figure
Mesoporous stilbene-based lanthanide metal organic frameworks: synthesis, photoluminescence and radioluminescence characteristics
Mesoporous non-interpenetrating stilbene-based lanthanide metal organic frameworks exhibits photo and radioluminescence behavior.</p
Unsupervised segmentation of irradiation\unicode{x2010}induced order\unicode{x2010}disorder phase transitions in electron microscopy
We present a method for the unsupervised segmentation of electron microscopy
images, which are powerful descriptors of materials and chemical systems.
Images are oversegmented into overlapping chips, and similarity graphs are
generated from embeddings extracted from a domain\unicode{x2010}pretrained
convolutional neural network (CNN). The Louvain method for community detection
is then applied to perform segmentation. The graph representation provides an
intuitive way of presenting the relationship between chips and communities. We
demonstrate our method to track irradiation\unicode{x2010}induced amorphous
fronts in thin films used for catalysis and electronics. This method has
potential for "on\unicode{x2010}the\unicode{x2010}fly" segmentation to
guide emerging automated electron microscopes.Comment: 7 pages, 3 figures. Accepted to Machine Learning and the Physical
Sciences Workshop, NeurIPS 202
Microstructural evolution and transmutation in tungsten under ion and neutron irradiation
This study aims to compare the effects of neutron and self-ion irradiation on the mechanical properties and microstructural evolution in W. Neutron irradiation at the HFR reactor to 1.67 dpa at 800 °C resulted in the formation of large Re and Os rich clusters and voids. The post-irradiation composition was measured using APT and verfified against FISPACT modelling. The measured Re and Os concentration was used to create alloys with equivalent concentrations of Re and Os. These alloys were exposed to self-ion irradiation to a peak dose of 1.7 dpa at 800 °C. APT showed that self-ion irradiation leads to the formation of small Os clusters, wheras under neutron irradiation large Re/Os clusters form. Voids are formed by both ion and neutron irradiation, but the voids formed by neutron irradiation are larger. By comparing the behaviour of W-1.4Re and W-1.4Re-0.1Os, suppression of Re cluster formation was observed. Irradiation hardening was measured using nanoindentation and was found to be 2.7 GPa, after neutron irradiation and 1.6 GPa and 0.6 GPa for the self-ion irradiated W-1.4Re and W-1.4Re-0.1Os. The higher hardening is attributed to the barrier strength of large voids and Re/Os clusters that are observed after neutron irradiation
Influence of permanent night work on the circadian rhythm of blood pressure
Abstract. Night workers exercise their labours activities and rest in contrary schedules to the chronobiological standards. This inversion leads the body to several adaptations, including changes in the circadian rhythm of blood pressure (BP). Objectives: To evaluate the BP in individuals who perform work at night, in order to objectively detail the BP circadian rhythm adaptations infixed night workers. Methods: A cross-sectional study enrolling 23 fixed night workers, both genders, was performed, with 24h BP measured with ambulatory blood pressure monitoring (ABPM) during a normal working day. Risk factors, anthropometric and lifestyle information were collected using a standard questionnaire. Results: Ambulatory BP demonstrated a pattern of adaptation to the sleep/activity cycle in all participants. BP dropped during the sleeping period (mean drop: -11.35±6.85) and was higher during the awakening period, reaching the highest results and greater BP variability during the working period. The chronobiological adaptation of the 24h BP was not dependent on sociodemographic or clinical characteristics. In addition, age, male gender, obesity, and those working less time were associated with higher BP mean values. Conclu-sions: The circadian rhythm of BP follows the working circadian profile of the individual.info:eu-repo/semantics/publishedVersio
Gender roles and their influence on life prospects for women in urban Karachi, Pakistan: a qualitative study
Pakistan is a patriarchal society where men are the primary authority figures and women are subordinate. This has serious implications on women's and men's life prospects.The aim was to explore current gender roles in urban Pakistan, how these are reproduced and maintained and influence men's and women's life circumstances.Five focus group discussions were conducted, including 28 women representing employed, unemployed, educated and uneducated women from different socio-economic strata. Manifest and latent content analyses were applied. Two major themes emerged during analysis: ‘Reiteration of gender roles’ and ‘Agents of change’. The first theme included perceptions of traditional gender roles and how these preserve women's subordination. The power gradient, with men holding a superior position in relation to women, distinctive features in the culture and the role of the extended family were considered to interact to suppress women. The second theme included agents of change, where the role of education was prominent as well as the role of mass media. It was further emphasised that the younger generation was more positive to modernisation of gender roles than the elder generation.This study reveals serious gender inequalities and human rights violations against women in the Pakistani society. The unequal gender roles were perceived as static and enforced by structures imbedded in society. Women routinely faced serious restrictions and limitations of autonomy. However, attainment of higher levels of education especially not only for women but also for men was viewed as an agent towards change. Furthermore, mass media was perceived as having a positive role to play in supporting women's empowerment
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