Ethical and Equitable Digital Health Research: Ensuring Self-Determination in Data Governance for Racialized Communities.

Recent studies highlight the need for ethical and equitable digital health research that protects the rights and interests of racialized communities. We argue for practices in digital health that promote data self-determination for these communities, especially in data collection and management. We suggest that researchers partner with racialized communities to curate data that reflects their wellness understandings and health priorities, and respects their consent over data use for policy and other outcomes. These data governance approach honors and builds on Indigenous Data Sovereignty (IDS) decolonial scholarship by Indigenous and non-indigenous researchers and its adaptations to health research involving racialized communities from former European colonies in the global South. We discuss strategies to practice equity, diversity, inclusion, accessibility and decolonization (EDIAD) principles in digital health. We draw upon and adapt the concept of Precision Health Equity (PHE) to emphasize models of data sharing that are co-defined by racialized communities and researchers, and stress their shared governance and stewardship of data that is generated from digital health research. This paper contributes to an emerging research on equity issues in digital health and reducing health, institutional, and technological disparities. It also promotes the self-determination of racialized peoples through ethical data management.

Hg Doping Induced Reduction in Structural Disorder Enhances the Thermoelectric Performance in AgSbTe2.

Defect engineering, achieved by precise tuning of the atomic disorder within crystalline solids, forms a cornerstone of structural chemistry. This nuanced approach holds the potential to significantly augment thermoelectric performance by synergistically manipulating the interplay between the charge carrier and lattice dynamics. Here, the current study presents a distinctive investigation wherein the introduction of Hg doping into AgSbTe2 serves to partially curtail structural disorder. This strategic maneuver mitigates potential fluctuations originating from pronounced charge and size disparities between Ag+ and Sb3+, positioned in octahedral sites within the rock salt structure. Hg doping significantly improves the phase stability of AgSbTe2 by restricting the congenital emergence of the Ag2Te minor secondary phase and promotes partial atomic ordering in the cation sublattice. Reduction in atomic disorder coalesced with a complementary modification of electronic structure by Hg doping results in increased carrier mobility. The formation of nanoscale superstructure with sizes (2-5 nm) of the order of phonon mean free path in AgSbTe2 is further promoted by reduced partial disorder, causes enhanced scattering of heat-carrying phonons, and results in a glass-like ultralow lattice thermal conductivity (∼0.32 W m-1 K-1 at 297 K). Cumulatively, the multifaceted influence of Hg doping, in conjunction with the consequential reduction in disorder, allows achieving a high thermoelectric figure-of-merit, zT, of ∼2.4 at ∼570 K. This result defies conventional paradigms that prioritize increased disorder for optimizing zT.

Youth response to climate change: Learning from Indigenous land-based camp at the Northern Saskatchewan Indigenous Communities, Canada.

This paper represents Youth's involvement in land-based learning in Indigenous culture camps (LLICP) in a powerful and innovative approach to addressing the pressing global issue of climate change. Following Indigenist and relational approaches, we (Indigenous and non-Indigenous youth and educators) explore the critical aspects of this initiative, highlighting its significance and potential impact. Indigenous communities have long held a deep connection with the land and possess traditional knowledge that is invaluable in combating climate change. The LLICP initiative involves organizing cultural camps designed for youth from diverse backgrounds to learn from Indigenous elders and community leaders about the vital relationship between the environment and Indigenous cultures. The LLICP provides a unique opportunity for young people to engage with Indigenous wisdom, traditional practices, and land-based teachings. Through Indigenous elders and knowledge-keepers guidelines, we learned a holistic understanding of sustainable living, biodiversity conservation, and the importance of preserving ecosystems. Our learning helped us, particularly our youths, to become proactive stewards of the environment and advocates for climate action. The LLICP fosters cross-cultural understanding and collaboration, encouraging a sense of unity among youths. The LLICP inspires innovative solutions to climate-related challenges and empowers youth to take leadership roles in their communities, advocating for sustainable policies and practices. The LLICP offers a powerful means of engaging young people in the fight against climate change while respecting and honoring Indigenous knowledge and heritage. It is a promising step towards a more sustainable and resilient future for all.

Meanings of indigenous land-based healing and the implications for water governance.

The continuous process of settler colonialism in Canada has profoundly impacted Indigenous Peoples' relationship with the Land and water, which holds immense significance in their healing journey. Reconnecting with the land and water through culturally rooted practices has far-reaching implications for the health and well-being of Indigenous communities. Maintaining a strong bond with the land and water is integral to Indigenous healing traditions. To gain insights into this connection we used a relational theoretical framework and engaged with Ministikwan Lake Cree Nation, a remote Indigenous community. Our approach centred around community-based participatory research, utilizing methods like deep listening, cultural camps and story-sharing to collect wisdom from community members, knowledge keepers, and Elders. The research findings show understanding the connection between Land-based healing practices and Indigenous-led water governance is critical to solving the water crises within remote Indigenous communities. This knowledge is indispensable for reshaping current water governance systems and ensuring the well-being of Indigenous communities across Canada.

High Thermoelectric Performance in Phonon-Glass Electron-Crystal Like AgSbTe2.

Achieving glass-like ultra-low thermal conductivity in crystalline solids with high electrical conductivity, a crucial requirement for high-performance thermoelectrics , continues to be a formidable challenge. A careful balance between electrical and thermal transport is essential for optimizing the thermoelectric performance. Despite this inherent trade-off, the experimental realization of an ideal thermoelectric material with a phonon-glass electron-crystal (PGEC) nature has rarely been achieved. Here, PGEC-like AgSbTe2 is demonstrated by tuning the atomic disorder upon Yb doping, which results in an outstanding thermoelectric performance with figure of merit, zT ≈ 2.4 at 573 K. Yb-doping-induced enhanced atomic ordering decreases the overlap between the hole and phonon mean free paths and consequently leads to a PGEC-like transport behavior in AgSbTe2 . A twofold increase in electrical mobility is observed while keeping the position of the Fermi level (EF ) nearly unchanged and corroborates the enhanced crystalline nature of the AgSbTe2 lattice upon Yb doping for electrical transport. The cation-ordered domains, lead to the formation of nanoscale superstructures (≈2 to 4 nm) that strongly scatter heat-carrying phonons, resulting in a temperature-independent glass-like thermal conductivity. The strategy paves the way for realizing high thermoelectric performance in various disordered crystals by making them amorphous to phonons while favoring crystal-like electrical transport.

Highly effective visible-light-induced H(2) generation by single-layer 1T-MoS(2) and a nanocomposite of few-layer 2H-MoS(2) with heavily nitrogenated graphene.

Two sorts of MoS2 : A single-layer, metallic form of MoS2 (1T-MoS2 ) and a nanocomposite of a second form of MoS2 (few-layer 2H-MoS2 ) with heavily nitrogenated reduced graphene oxide (NRGO; N content ca. 15 %) show outstanding performance in the production of H2 under visible-light illumination.

Modular Nanostructures Facilitate Low Thermal Conductivity and Ultra-High Thermoelectric Performance in n-Type SnSe.

Single crystals of SnSe have gained considerable attention in thermoelectrics due to their unprecedented thermoelectric performance. However, polycrystalline SnSe is more favorable for practical applications due to its facile chemical synthesis procedure, processability, and scalability. Though the thermoelectric figure of merit (zT) of p-type bulk SnSe polycrystals has reached >2.5, zT of n-type counterpart is still lower and lies around ≈1.5. Herein, record high zT of 2.0 in n-type polycrystalline SnSe0.92  + x mol% MoCl5 (x = 0-3) samples is reported, when measured parallel to the spark plasma sintering pressing direction due to the simultaneous optimization of n-type carrier concentration and enhanced phonon scattering by incorporating modular nano-heterostructures in SnSe matrix. Modular nanostructures of layered intergrowth [(SnSe)1.05 ]m (MoSe2 )n like compounds embedded in SnSe matrix scatters the phonons significantly leading to an ultra-low lattice thermal conductivity (κlat ) of ≈0.26 W m-1 K-1 at 798 K in SnSe0.92  + 3 mol% MoCl5 . The 2D layered modular intergrowth compound resembles the nano-heterostructure and their periodicity of 1.2-2.6 nm in the SnSe matrix matches the phonon mean free path of SnSe, thereby blocking the heat carrying phonons, which result in low κlat and ultra-high thermoelectric performance in n-type SnSe.

BCN: a graphene analogue with remarkable adsorptive properties.

A new analogue of graphene containing boron, carbon and nitrogen (BCN) has been obtained by the reaction of high-surface-area activated charcoal with a mixture of boric acid and urea at 900 degrees C. X-ray photoelectron spectroscopy and electron energy-loss spectroscopy reveal the composition to be close to BCN. The X-ray diffraction pattern, high-resolution electron microscopy images and Raman spectrum indicate the presence of graphite-type layers with low sheet-to-sheet registry. Atomic force microscopy reveals the sample to consist of two to three layers of BCN, as in a few-layer graphene. BCN exhibits more electrical resistivity than graphene, but weaker magnetic features. BCN exhibits a surface area of 2911 m(2) g(-1), which is the highest value known for a B(x)C(y)N(z) composition. It exhibits high propensity for adsorbing CO(2) ( approximately 100 wt %) at 195 K and a hydrogen uptake of 2.6 wt % at 77 K. A first-principles pseudopotential-based DFT study shows the stable structure to consist of BN(3) and NB(3) motifs. The calculations also suggest the strongest CO(2) adsorption to occur with a binding energy of 3.7 kJ mol(-1) compared with 2.0 kJ mol(-1) on graphene.

Defect driven spin state transition and the existence of half-metallicity in CoO.

We unveil the native defect induced high spin to low spin state transition in [Formula: see text] and half-metallicity in CoO. First principles calculations unravel that, defect density holds a key role in dictating the spin-state transition in [Formula: see text] ion in CoO, and introducing the half-metallicity. Charge transfer in the vicinity of vacancy plane favors the stabilization and coexistence of bivalent [Formula: see text] and trivalent [Formula: see text] ion in CoO. We propose that defect engineering could serve as a route to design the half metallicity in transition metal mono-oxides.

Bulk Single Crystal-Like Structural and Magnetic Characteristics of Epitaxial Spinel Ferrite Thin Films with Elimination of Antiphase Boundaries.

Spinel ferrite NiFe2 O4 thin films have been grown on three isostructural substrates, MgAl2 O4 , MgGa2 O4 , and CoGa2 O4 using pulsed laser deposition. These substrates have lattice mismatches of 3.1%, 0.8%, and 0.2%, respectively, with NiFe2 O4 . As expected, the films grown on MgAl2 O4 substrate show the presence of the antiphase boundary defects. However, no antiphase boundaries (APBs) are observed for films grown on near-lattice-matched substrates MgGa2 O4 and CoGa2 O4 . This demonstrates that by using isostructural and lattice-matched substrates, the formation of APBs can be avoided in NiFe2 O4 thin films. Consequently, static and dynamic magnetic properties comparable with the bulk can be realized. Initial results indicate similar improvements in film quality and magnetic properties due to the elimination of APBs in other members of the spinel ferrite family, such as Fe3 O4 and CoFe2 O4 , which have similar crystallographic structure and lattice constants as NiFe2 O4 .

Pd-Pt alloys nanowires as support-less electrocatalyst with high synergistic enhancement in efficiency for methanol oxidation in acidic medium.

In a facile approach, Pd73Pt27 alloy nanowires (NWs) with large aspect ratios were synthesized in high yield by using sacrificial templates. Unlike majority of processes, our synthesis was carried out in aqueous solution with no intermittent separating stages for the products, while maintaining the NW morphology up to ∼30% of Pt. Upon evaporation of their dispersion, the NWs transform into a stable porous membrane due to self-entanglement and can be directly lifted and employed for electrocatalytic applications without external catalyst supports. We show that the NW membranes exhibit efficient electrocatalytic performance for methanol oxidation reaction (MOR) with 10 times higher mass activity and 4.4 times higher specific activity in acidic media as compared to commercial Pt catalysts. The membrane electrocatalysts is robust and exhibited very good stability with retention of ∼70% mass-activity after 4000 potential cycles. Since Pd was found to be inert towards MOR in acidic medium, our investigation provides a direct estimate of synergistic enhancement of efficiency. Over 10 times increment of mass activity appears to be significantly higher than previous investigations in various other reaction media.

High-yield synthesis of sub-10 nm Pt nanotetrahedra with bare ⟨111⟩ facets for efficient electrocatalytic applications.

Unlike other shapes, the design of tetrahedral Pt nanocrystals (Pt-NTd), which have the largest number of Pt(111) surface atoms and highest catalytic activities toward the electron transfer reactions, has widely been considered a synthetic challenge due to their thermodynamic instability. Here, we show that, by inducing their nucleation on functionalized carbon, Pt NTds can be obtained with tunable sizes and high yields. The carbon support anchors the nanocrystals early and prevents their oriented attachment leading to nanowire formation. Therein, an in situ generated amine is crucial for stabilization of Pt-NTds, which can later be removed to expose the Pt(111) facets for higher catalytic efficiency. The bare nanocrystals exhibit much improved stability and electrocatalytic activity characteristic of Pt(111) toward oxygen reduction reaction (ORR) and methanol and formic acid oxidation reactions. For example, ∼90% of their activity was retained after 5000 potential cycles, while the ORR onset potential was recorded to be very high, 1.01 V vs reversible hydrogen electrode (RHE).

Mechanochemical Synthesis of Free-Standing Platinum Nanosheets and Their Electrocatalytic Properties.

Robust, 26 nm thick free-standing platinum nanosheets, an extremely rare morphology for metal nanostructures, are obtained by employing fluid induced shearing force of the order of 1.8 N and differential shear-stress of 0.5 kPa across the diameter of a Te template nanorod undergoing galvanic displacement by Pt4+ . Corrugation leads to their large surface area and much improved electrocatalytic properties when compared with conventional Pt catalysts.

Graphene analogues of layered metal selenides.

Graphene analogues of MoSe(2) and WSe(2) have been prepared by three different chemical methods and characterized by electron microscopy and other methods. Graphene analogues of these diselenides as well as of GaSe have also been obtained by liquid-phase exfoliation. Raman spectra of the graphene analogues show significant changes relative to those of the bulk samples.

Graphene analogues of BN: novel synthesis and properties.

Enthused by the fascinating properties of graphene, we have prepared graphene analogues of BN by a chemical method with a control on the number of layers. The method involves the reaction of boric acid with urea, wherein the relative proportions of the two have been varied over a wide range. Synthesis with a high proportion of urea yields a product with a majority of 1-4 layers. The surface area of BN increases progressively with the decreasing number of layers, and the high surface area BN exhibits high CO(2) adsorption, but negligible H(2) adsorption. Few-layer BN has been solubilized by interaction with Lewis bases. We have used first-principles simulations to determine structure, phonon dispersion, and elastic properties of BN with planar honeycomb lattice-based n-layer forms. We find that the mechanical stability of BN with respect to out-of-plane deformation is quite different from that of graphene, as evident in the dispersion of their flexural modes. BN is softer than graphene and exhibits signatures of long-range ionic interactions in its optical phonons. Finally, structures with different stacking sequences of BN have comparable energies, suggesting relative abundance of slip faults, stacking faults, and structural inhomogeneities in multilayer BN.