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In this work we have studied the elongation of silver nanoparticles irradiated with 40 MeV Bromine ions by means of in situ optical measurements, transmission electron microscopy and molecular dynamics simulations. The localized surface plasmon resonance of silver nanoparticles has a strong dependence on the particle shape and size, which allowed us to obtain the geometrical parameters with remarkable accuracy by means of a fit of the optical spectra. Optical results have been compared with transmission electron microscopy images and molecular dynamics simulations and the agreement is excellent in both cases. An important advantage of in situ measurements is that they yield an extremely detailed information of the full elongation kinetics. Final nanoparticle elongation depends on a complex competition between single-ion deformation, Ostwald ripening and dissolution. Building and validating theoretical models with the data reported in this work should be easier than with the information previously available, due to the unprecedented level of kinetic details obtained from the in situ measurements.

Globally, Indigenous populations have been impacted by colonization. Populations who have endured colonization are at higher risk of developing chronic diseases. Canada’s Truth and Reconciliation Commission emphasizes reducing barriers to participation in physical activity and recommends the creation of culturally relevant and supportive policies and programing. Physical activity is a cornerstone in health promotion and public health to combat chronic diseases; however, in Canada, Indigenous developed physical activity programing is sparse, and those targeting women are non-existent in some regions. Makoyoh'sokoi (The Wolf Trail Program) is an 18-week long, holistic wellness program that was created by and for Indigenous women. Makoyoh'sokoi was developed by communities following extensive consultation and cultural oversight. Makoyoh'sokoi’s core program consists of 12 weeks of weekly physical activity programing and health education, followed by another 6 weeks of weekly health education. Notably, communities have control over the program to modify based on individual needs and challenges. Programs commence and conclude with a ceremony with Elders giving a blessing and opening each other to connection. The goals of Makoyoh'sokoi are to empower women, improve health outcomes, and to implement a sustainable program by training a network of community members in their respective communities to facilitate delivery.

Au nanoparticles (NPs) with a size in the 2–12 nm range have been grown in silica by 2 MeV Au-ion implantation and a subsequent thermal annealing in air. The as-prepared Au NPs were irradiated with 10 MeV Si ions elongating some of them. From transmission electron microscopy in Z-contrast mode, we observed a narrow size distribution of the minor axis of the deformed NPs, which presents its higher frequency around 6–7 nm and have a saturation about 9 nm. This final result agrees well with the diameter of the track formed by Si ions of 10 MeV in silica, supporting the thermal spike model, which would explain the deformation of the NPs. In this model, the NP melts and creeps along the ion track. Our results show that the NP crystallization is in the fcc structure. On the other hand, a 200 keV electron irradiation provoked roundness on the previously elongated nanoparticles. This effect was observed in situ by high-resolution transmission electron microscopy, showing additionally that, during the roundness process, the fcc structure, as well as its crystalline orientation, remain unchanged. Thus, this study shows how Au NPs embedded in silica, within this size distribution, keep the fcc bulk structure under both ion and electron irradiations.

We studied the photoluminescence (PL) of Si nanocrystals (Si-NCs) embedded in SiO2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm) inside the SiO2 achieving a robust and better protected system. After metal ion implantation (Ag or Au), and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs) could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H2/N2 and Ar) to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

The photoluminescence and third-order nonlinear optical effects of co-implanted silicon nanoparticles and nitrogen ions in a silica matrix were studied. Experimental evidence shows the potential of nitrogen ions for changing optical properties exhibited by silicon nanoparticles implanted in an integrated system. The modification of the optical bandgap and photoluminescent intensity in the studied nanomaterials by the incorporation of nitrogen was analyzed. Standard two−wave mixing experiments were conducted using nanosecond and picosecond laser pulses at 532 nm wavelength. At this off-resonance condition, only multiphoton excitation can promote electrons at energies above the optical bandgap of the silicon nanoparticles. The picosecond results show that the co-implanted sample with nitrogen exhibits a three-fold enhancement of the nonlinear Kerr response. Femtosecond z-scan measurements were undertaken at 800 nm in order to explore the modification of the ultrafast nonlinear response of the samples that revealed a purely electronic Kerr nonlinearity together to saturable absorption of the SiNPs in the near-infrared. Remarkably, femtosecond results reveal that nitrogen co-implantation in the SiNPs system derives from the quenching of the third-order nonlinear optical behavior. These findings pointed out a simple approach for engineering the optical bandgap of nanocomposites, which can be controlled by a doping process based on ion-implanted nitrogen. It is highlighted that the enhanced light-matter interactions induced by nitrogen implantation can be useful for developing nonlinear integrated silicon photonics nanodevices with low power excitation.

This study explores magnetization exhibited by nanoscale platinum-based structures embedded in pure silica plates. A superposition of laser pulses in the samples produced periodic linear arrangements of micro-sized structures. The samples were integrated by PtO 2 microstructures (PtOΣs) with dispersed Pt oxide nanoparticles in their surroundings. The characterization of the materials was performed by high transmission electron microscopy studies. Furthermore, topographical and magnetic effects on the sample surfaces were analyzed by atomic force microscopy and magnetic force microscopy, respectively. The magnetic measurements indicated an enhancement in the gradient phase shift and in the gradient force related to the magnetic PtOΣs. The possibility of tuning the magnetic characteristics of the samples through contact with a Nd 2 Fe 14 B magnet was demonstrated. This process corresponds to an innovative method for obtaining magnetic PtOΣs induced by laser pulses. Moreover, an increase in the compactness of the silica with platinum-based structures was confirmed by an evaluation of the effective elastic modulus with reference to pure silica. The multimodal magnetic structures studied in this work seem to be candidates for developing high-density magnetic storage media.

The third-order nonlinear infrared and ultraviolet properties exhibited by silicon quantum dots irradiated by ultrashort pulses were studied. The samples were prepared by 1.5 MeV Si+2 ion implantation processes in high-purity silica substrates. Femtosecond z -scan measurements conducted at 830 nm wavelength revealed strong self-focusing effects together with two-photon absorption that can be switched to saturable absorption as a function of the input irradiance. Changes in the main physical mechanism responsible for the picosecond absorptive nonlinearity in the sample were also observed at 355 nm, made possible by the assistance of photothermal phenomena. Ultraviolet self-diffraction explorations allowed us to estimate the Kerr effect of the nanostructures. Potential applications for developing all-optical filtering functions performed by silicon-based nanosystems can be considered.

Awareness of environmental quality has captured the respect of many individuals, but a lack of action hinders the nation’s ability to overcome the present environmental challenges. Despite the increasing popularity of sustainability and ongoing efforts toward sustainable development, more research is needed to bridge the barrier between attitudes and behaviors. The aim of this research was to assess the correlation between behaviors and attitudes based on the Theory of Reasoned Action (TRA) and the Theory of Planned Behavior (TPB), and to determine how much people are willing to pay in order to protect the environment with the application of the Contingent Valuation Method (CVM). In this quantitative, experimental study, an assessment tool comprised of 11 questions / statements was created to explore the lifestyles and behavioral beliefs of students at a higher education institution (HEI). An anonymous survey link was emailed to approximately 5,500 students. At least 352 surveys were started, and 304 surveys were finished (completion rate = 86.4%). The assessment of environmental behaviors disclosed a lack of commitment, except in the cases of turning off lights and using the washing machine for large loads of laundry. Conversely, an assessment of environmental attitudes revealed higher tendencies overall, except in the case of taking a sustainability course. In addition, the intention for engaging in conservation behaviors is positively influenced by environmental attitudes, and people are willing to pay a mean price of $22.87 per month for emissions-free electricity to protect the environment. As HEIs continue to institutionalize sustainability, it is important to gain insight on the barriers to accomplishing the goal of climate neutrality. The significance and originality of this research was to analyze the statistical correlation between environmental behavior and environmental attitudes. The information will be useful for planning committees and policy makers.

The optical damage associated with high intensity laser excitation of silver nanoparticles (NPs) was studied. In order to investigate the mechanisms of optical nonlinearity of a nanocomposite and their relation with its ablation threshold, a high-purity silica sample implanted with Ag ions was exposed to different nanosecond and picosecond laser irradiations. The magnitude and sign of picosecond refractive and absorptive nonlinearities were measured near and far from the surface plasmon resonance (SPR) of the Ag NPs with a self-diffraction technique. Saturable optical absorption and electronic polarization related to self-focusing were identified. Linear absorption is the main process involved in nanosecond laser ablation, but non-linearities are important for ultrashort picosecond pulses when the absorptive process become significantly dependent on the irradiance. We estimated that near the resonance, picosecond intraband transitions allow an expanded distribution of energy among the NPs, in comparison to the energy distribution resulting in a case of far from resonance, when the most important absorption takes place in silica. We measured important differences in the ablation threshold and we estimated that the high selectiveness of the SPR of Ag NPs as well as their corresponding optical nonlinearities can be strongly significant for laser-induced controlled explosions, with potential applications for biomedical photothermal processes.