The role and properties of interfaces are well understood in the field of semiconductors and aqueous electrochemistry, but less so in many cases of solid-state electrolytes. In this study, the interface between a solid-state proton conductor BaZr_0.9Y_0.1O_3−δ (BZY10) and a metal phase (Pt), consisting of a positively charged core and an adjacent space charge layer (SCL) with opposite charges, was investigated for proton ceramic fuel cell (PCFC) applications. Considering the H₂ oxidation reaction (HOR) at the Pt/BZY10 interface, the resistances of proton transport through the SCL (R_SCL(H⁺)) and electron charge transfer (ECT) reactions (R_ECT) were identified using the distribution of relaxation time (DRT) analysis on the impedance spectra. The R_SCL(H⁺) is shown to be independent on pH₂ and sensitive to pH₂O. And also, the positive dependency of 1/R_ECT with pH₂O reveals a decrease of the electrical potential at the Pt/BZY10 interface (Δφ(x₁)) with increasing pH₂O. With the presence of a SCL, the exchange current density (j₀) is a function of the anodic potential. As a result, the Tafel equation is modified based on the variable j₀, giving an additional resistance (R^SCL _ECT) with the expression of on top of the ideal R_ECT (absence of a SCL). At high positive bias (>0.2 V), a pronounced SCL effect on the kinetics of ECT reactions is estimated, with the ratio of R^SCL _ECT/R_ECT being over 50%. This study is a first-time experimental investigation of the SCL effect at a metal/solid-state ionic conductor interface, demonstrated in the case of the HOR.

Nanomaterials in the food industry are used as food additives, and the main function of these food additives is to improve food qualities including texture, flavor, color, consistency, preservation, and nutrient bioavailability. This review aims to provide an overview of the distribution, fate, and environmental and health impacts of food additive nanomaterials in soil and aquatic ecosystems. Some of the major nanomaterials in food additives include titanium dioxide, silver, gold, silicon dioxide, iron oxide, and zinc oxide. Ingestion of food products containing food additive nanomaterials via dietary intake is considered to be one of the major pathways of human exposure to nanomaterials. Food additive nanomaterials reach the terrestrial and aquatic environments directly through the disposal of food wastes in landfills and the application of food waste-derived soil amendments. A significant amount of ingested food additive nanomaterials (> 90 %) is excreted, and these nanomaterials are not efficiently removed in the wastewater system, thereby reaching the environment indirectly through the disposal of recycled water and sewage sludge in agricultural land. Food additive nanomaterials also reach the environments directly through the disposal of food wastes in landfills and the application of food waste-derived soil amendments. Food additive nanomaterials undergo various transformation and reaction processes, such as adsorption, aggregation-sedimentation, desorption, degradation, dissolution, and bio-mediated reactions in the environment. These processes significantly impact the transport and bioavailability of nanomaterials as well as their behaviour and fate in the environment. These nanomaterials are toxic to soil and aquatic organisms, and reach the food chain through plant uptake and animal transfer. The environmental and health risks of food additive nanomaterials can be overcome by eliminating their emission through recycled water and sewage sludge.

The grassland in the Qinghai–Tibetan plateau provide habitat for many indigenous and introduced ruminants which perform important ecological functions that impact the whole Qinghai–Tibetan plateau ecosystem. These indigenous Tibetan ruminants have evolved several adaptive traits to withstand the severe environmental conditions, especially cold, low oxygen partial pressure, high altitude, strong UV radiation, and poor forage availability on the alpine rangelands. Despite the challenges to husbandry associated with the need for enhanced adaptation, several domesticated ruminants have also been successfully introduced to the alpine pasture regions to survive in the harsh environment. For ruminants, these challenging conditions affect not only the host, but also their commensal microbiota, especially the diversity and composition of the rumen microbiota; multiple studies have described tripartite interactions among host-environment-rumen microbiota. Thus, there are significant benefits to understanding the role of rumen microbiota in the indigenous and introduced ruminants of the Qinghai–Tibetan plateau, which has co-evolved with the host to ensure the availability of specific metabolic functions required for host survival, health, growth, and development. In this report, we systemically reviewed the dynamics of rumen microbiota in both indigenous and introduced ruminants (including gut microbiota of wild ruminants) as well as their structure, functions, and interactions with changing environmental conditions, especially low food availability, that enable survival at high altitudes. We summarized that three predominant driving factors including increased VFA production, enhanced fiber degradation, and lower methane production as indicators of higher efficiency energy harvest and nutrient utilization by microbiota that can sustain the host during nutrient deficit. These cumulative studies suggested alteration of rumen microbiota structure and functional taxa with genes that encode cellulolytic enzymes to potentially enhance nutrient and energy harvesting in response to low quality and quantity forage and cold environment. Future progress toward understanding ruminant adaptation to high altitudes will require the integration of phenotypic data with multi-omics analyses to identify host-microbiota co-evolutionary adaptations enabling survival on the Qinghai–Tibetan plateau.