Crystalline structure and orientation of gold clusters grown in preformed nanometer-sized pits

Abstract Gold clusters were produced by condensing evaporated gold in nanometer-sized preformed pits on the surface of highly Ž . oriented pyrolytic graphite HOPG . The height of the clusters was 6.7 " 0.7 nm as measured with scanning tunneling microscopy in ultrahigh vacuum, the lateral width was 10.1 " 1.9 nm as determined with transmission electron microscopy Ž . TEM . Using TEM for electron diffraction, we obtained information on the crystalline structure of the clusters. The Ž . intensity of the observed diffraction rings shows the preferential orientation of the clusters with the 111 plane of the gold Ž . lattice parallel to the 0001 surface of HOPG. This was compared to the diffraction pattern of gold clusters produced in the gas phase by inert-gas evaporation and deposited on a flat HOPG surface at room temperature as complete units which showed no preferential orientation. The directional alignment in the surface plane as it is described in the literature for larger gold crystallites grown on a flat HOPG surface is not observed for the nanometer-sized clusters grown in pits

Different W cluster deposition regimes in pulsed laser ablation observed by in situ Scanning Tunneling Microscopy

We report on how different cluster deposition regimes can be obtained and observed by in situ Scanning Tunneling Microscopy (STM) by exploiting deposition parameters in a pulsed laser deposition (PLD) process. Tungsten clusters were produced by nanosecond Pulsed Laser Ablation in Ar atmosphere at different pressures and deposited on Au(111) and HOPG surfaces. Deposition regimes including cluster deposition-diffusion-aggregation (DDA), cluster melting and coalescence and cluster implantation were observed, depending on background gas pressure and target-to-substrate distance which influence the kinetic energy of the ablated species. These parameters can thus be easily employed for surface modification by cluster bombardment, deposition of supported clusters and growth of films with different morphologies. The variation in cluster mobility on different substrates and its influence on aggregation and growth mechanisms has also been investigated.Comment: 12 pages (3 figures); Surface Science (accepted

Suicide associated with COVID-19 infection: an immunological point of view

OBJECTIVE: Coronavirus disease 2019 (COVID-19) is a pandemic and leading cause of death. Beyond the deaths directly caused by the virus and the suicides related to the psychological response to the dramatic changes as socioeconomic related to the pandemic, there might also be suicides related to the inflammatory responses of the infection. Infection induces inflammation as a cytokine storm, and there is an increasing number of studies that report a relationship between infection and suicide. MATERIALS AND METHODS: We searched the World Health Organization status report and the PubMed database for keywords (COVID-19, suicide, infection, inflammation, cytokines), and reviewed five cytokine pathways between suicide and inflammation using two meta-analyses and two observational studies starting from November 31, 2020, focusing on the relationship between suicide and inflammation by infection. First, we discussed existing evidence explaining the relationship between suicidal behaviors and inflammation. Second, we summarized the inflammatory features found in COVID-19 patients. Finally, we highlight the potential for these factors to affect the risk of suicide in COVID-19 patients. RESULTS: Patients infected with COVID-19 have high amounts of IL-1β, IFN-γ, IP10, and MCP1, which may lead to Th1 cell response activation. Also, Th2 cytokines (e.g., IL-4 and IL-10) were increased in COVID-19 infection. In COVID-19 patients, neurological conditions, like headache, dizziness, ataxia, seizures, and others have been observed. CONCLUSIONS: COVID-19 pandemic can serve as a significant environmental factor contributing directly to increased suicide risk; the role of inflammation by an infection should not be overlooked

Flexible working arrangements, work-family conflict, and culture: Multilevel effects on country-level outcomes

Recent dramatic transformations in the workforce call for a better understanding of flexible working arrangements (FWA) and their implications, particularly in the context of work-family conflict (WFC). Moreover, a paucity in research has examined the way in which FWA and WFC influence country-level outcomes and whether FWA-WFC relationships differ as a function of relevant sociocultural factors. Through the lens of the personal resource allocation (PRA) and social identity theories, the present study tested a multilevel moderated 1-1-2 mediation, whereby (1) individual-level FWA predicts country-level productivity, innovation, and well-being via individual-level WFC and (2) country culture (individualism, masculinity, indulgence) moderates FWA-WFC relationships. Multilevel structural equation modeling (MSEM) analysis of nationally-representative archival data (N = 46,005) across 33 countries revealed FWA do influence levels of WFC. The strength and direction of such relationships however depend upon the type of FWA (i.e., flexplace or flextime) and the directionality of work-family conflict (i.e., work interfering with family or family interfering with work) examined. Country-level variables, namely, productivity and the HDI, are significant cross-level criteria. Although the cultural dimensions did not significantly moderate FWA-WFC relationships, indulgence was a meaningful cross-level predictor of WFC. Additional research is required. Even so, the findings here prompt several avenues of further empirical inquiry and provide preliminary support for a cross-level (micro-macro), bottom-up approach. Moreover, they offer several relevant insights for practice. Such implications are important as researchers and practitioners alike respond to today’s increasingly “work-from-home economy” (Bloom, 2020, p. 1)