Green Chemistry: Advanced Electrocatalysts and System Design for Ammonia Oxidation

The hazards associated with handling hydrogen fuels have driven people to consider alternative clean and sustainable fuel types. Ammonia shows significant potential for this task as both a direct fuel and hydrogen carrier due to its unique features of facile transportation and low cost. Regarding this, electrochemical ammonia oxidation reaction (AOR) is the essential process for utilizing ammonia for energy applications, either for hydrogen production via ammonia splitting or energy generation via direct ammonia fuel cells, which is highly commercially promising. On this basis, the development of high‐performance and economic electrocatalysts for AOR is critical. In this review, the kinetics and mechanism of ammonia electrooxidation are first discussed to provide a foundation to understand the current issues associated with this technology, and then a comprehensive presentation on the different types of electrocatalysts for AOR is illustrated. Afterward, an outlook is presented and the possible research directions for AOR electrocatalysis are proposed, which is expected to shed light on the future development of this promising technology

Spatial–Temporal Patterns of Sympatric Asiatic Black Bears (<i>Ursus thibetanus</i>) and Brown Bears (<i>Ursus arctos</i>) in Northeastern China

Studying the spatial and temporal interactions between sympatric animal species is essential for understanding the mechanisms of interspecific coexistence. Both Asiatic black bears (Ursus thibetanus) and brown bears (Ursus arctos) inhabit northeastern China, but their spatial–temporal patterns and the mechanism of coexistence were unclear until now. Camera traps were set in Heilongjiang Taipinggou National Nature Reserve (TPGNR) from January 2017 to December 2017 to collect photos of the two sympatric bear species. The Pianka index, kernel density estimation, and the coefficient of overlap were used to analyze the spatial and temporal patterns of the two sympatric species. Our findings indicated that the spatial overlap between Asiatic black bears and brown bears was low, as Asiatic black bears occupied higher elevations than brown bears. The two species’ temporal activity patterns were similar at sites where only one species existed, yet they were different at the co–occurrence sites. Asiatic black bears and brown bears are competitors in this area, but they can coexist by changing their daily activity patterns. Compared to brown bears, Asiatic black bears behaved more diurnally. Our study revealed distinct spatial and temporal differentiation within the two species in TPGNR, which can reduce interspecific competition and facilitate coexistence between them

Spatial-temporal patterns of human-wildlife conflicts under coupled impact of natural and anthropogenic factors in Mt. Gaoligong, western Yunnan, China

Human-wildlife conflicts (HWC) are major conservation concerns that threaten both wildlife and rural livelihoods, and can vary spatially and temporally in diverse environments. A better understanding of HWC enhances mitigation strategies and promotes human-wildlife coexistence. We gathered HWC incidents from 2012 to 2021 in Longyang District, Yunnan Province, China, to assess their spatial-temporal patterns and determinants. We found that HWC were distributed unevenly, with more occurring near the protected area and away from densely populated areas. Poisson regression indicated that forests and croplands were the key factors influencing the spatial patterns of HWC for Asiatic black bear (Ursus thibetanus), but shrubs for rhesus monkey (Macaca mulatta). Furthermore, the HWC occurrences fluctuated across time, peaking in August-October. These conflicts intensified between 2012 and 2021, mainly involving wild boars (Sus scrofa) and rhesus monkeys, while HWC involving Asiatic black bears declined slightly. We suggest a multi-faceted strategy with compensation, prevention, and conservation awareness to mitigate HWC in this region

A framework for assessing variations in ecological networks to support wildlife conservation and management

Habitat fragmentation poses a considerable threat to global biodiversity loss, making the study of landscape connectivity and ecological networks essential in an ever-changing environment. Of particular importance is the assessment of network dynamics, as it can provide invaluable specific insights for conservation and management strategies. This research proposes a framework to assess variations in ecological networks and identify conservation priorities. In this framework, we applied multi-methods to collect species occurrence and create resistance surfaces based on habitat suitability from the MaxEnt model. By using diverse approaches such as the least-cost model, circuit model, and centrality mapper, we identified ecological corridors between core areas and determined their centrality. Furthermore, we employed multi-level metrics to measure changes within ecological networks. Additionally, we introduced two indices to evaluate human disturbance faced by core habitats. We proposed a novel method that considers core habitats’ centrality and human disturbance to identify conservation priorities. Specifically, using the Asiatic Black Bear (Ursus thibetanus) as a case species, we examined the variations in ecological network and human disturbance across 2000–2020 in Western Yunnan, China. Our study revealed overall improvement with local losses in the availability and connectivity of black bear habitats in Western Yunnan from 2000 to 2020. However, the core habitats have been facing an escalating human disturbance. Our approach provides a framework for assessing dynamic ecological networks that can be applied to diverse species, landscapes, and scenarios. Furthermore, this approach helps guide conservation and management to promote human-wildlife coexistence in a changing environment

Identifying climate refugia and its potential impact on Tibetan brown bear (Ursus arctos pruinosus) in Sanjiangyuan National Park, China

Climate change has direct impacts on wildlife and future biodiversity protection efforts. Vulnerability assessment and habitat connectivity analyses are necessary for drafting effective conservation strategies for threatened species such as the Tibetan brown bear (Ursus arctos pruinosus). We used the maximum entropy (MaxEnt) model to assess the current (1950–2000) and future (2041–2060) habitat suitability by combining bioclimatic and environmental variables, and identified potential climate refugia for Tibetan brown bears in Sanjiangyuan National Park, China. Next, we selected Circuit model to simulate potential migration paths based on current and future climatically suitable habitat. Results indicate a total area of potential suitable habitat under the current climate scenario of approximately 31,649.46 km2, of which 28,778.29 km2 would be unsuitable by the 2050s. Potentially suitable habitat under the future climate scenario was projected to cover an area of 23,738.6 km2. Climate refugia occupied 2,871.17 km2, primarily in the midwestern and northeastern regions of Yangtze River Zone, as well as the northern region of Yellow River Zone. The altitude of climate refugia ranged from 4,307 to 5,524 m, with 52.93% lying at altitudes between 4,300 and 4,600 m. Refugia were mainly distributed on bare rock, alpine steppe, and alpine meadow. Corridors linking areas of potentially suitable brown bear habitat and a substantial portion of paths with low-resistance value were distributed in climate refugia. We recommend various actions to ameliorate the impact of climate change on brown bears, such as protecting climatically suitable habitat, establishing habitat corridors, restructuring conservation areas, and strengthening monitoring efforts

Identifying climate refugia and its potential impact on Tibetan brown bear ( Ursus arctos pruinosus

Climate change has direct impacts on wildlife and future biodiversity protection efforts. Vulnerability assessment and habitat connectivity analyses are necessary for drafting effective conservation strategies for threatened species such as the Tibetan brown bear (Ursus arctos pruinosus). We used the maximum entropy (MaxEnt) model to assess the current (1950–2000) and future (2041–2060) habitat suitability by combining bioclimatic and environmental variables, and identified potential climate refugia for Tibetan brown bears in Sanjiangyuan National Park, China. Next, we selected Circuit model to simulate potential migration paths based on current and future climatically suitable habitat. Results indicate a total area of potential suitable habitat under the current climate scenario of approximately 31,649.46 km2, of which 28,778.29 km2 would be unsuitable by the 2050s. Potentially suitable habitat under the future climate scenario was projected to cover an area of 23,738.6 km2. Climate refugia occupied 2,871.17 km2, primarily in the midwestern and northeastern regions of Yangtze River Zone, as well as the northern region of Yellow River Zone. The altitude of climate refugia ranged from 4,307 to 5,524 m, with 52.93% lying at altitudes between 4,300 and 4,600 m. Refugia were mainly distributed on bare rock, alpine steppe, and alpine meadow. Corridors linking areas of potentially suitable brown bear habitat and a substantial portion of paths with low-resistance value were distributed in climate refugia. We recommend various actions to ameliorate the impact of climate change on brown bears, such as protecting climatically suitable habitat, establishing habitat corridors, restructuring conservation areas, and strengthening monitoring efforts

Single-Cell Transcriptomics Reveals the Difference of Aortic Atherosclerosis Response to Phytosterols and Oxidation Products of Sterols

ScopePhytosterols (PS) and sterol oxidation products are key dietary factors influencing atherosclerosis besides cholesterol, although the mechanisms remain elusive. Recently, single-cell RNA sequencing (scRNA-seq) has revealed the heterogeneity of multiple cell types associated with complex pathogenesis in atherosclerosis development. Methods and resultsHere, scRNA-seq is performed to investigate the alterations in the aortic cells from ApoE(-/-) mice induced by diet-derived PS or two sterol oxidation products, phytosterols oxidation products (POPs), and cholesterol oxidation products (COPs). The study identifies four fibroblast subpopulations with different functions, and immunofluorescence demonstrates their spatial heterogeneity, providing evidence that suggests the transformation of smooth muscle cells (SMCs) and fibroblasts in atherosclerosis. The composition and gene expression profiles of aortic cells change broadly in response to PS/COPs/POPs exposure. Notably, PS exhibits an atheroprotective effect where different gene expressions are mainly found in B cells. Exposure to COPs accelerates atherosclerosis and results in marked alternations in myofibroblast subpopulations and T cells, while POPs only alter fibroblast subpopulations and B cells. ConclusionThe data elucidate the effects of dietary PS/COPs/POPs on aortic cells during atherosclerosis development, especially on the newly identified fibroblast subpopulations

Use of DNA metabarcoding of bird pellets in understanding raptor diet on the Qinghai-Tibetan Plateau of China

Background: Diet analysis is essential to understanding the functional role of large bird species in food webs. Morphological analysis of regurgitated bird pellet contents is time intensive and may underestimate biodiversity. DNA metabarcoding has the ability to circumvent these issues, but has yet to be done. Methods: We present a pilot study using DNA metabarcoding of MT-RNR1 and MT-CO1 markers to determine the species of origin and prey of 45 pellets collected in Qinghai and Gansu Provinces, China. Results: We detected four raptor species [Eurasian Eagle Owl (Bubo bubo), Saker Falcon (Falco cherrug), Steppe Eagle (Aquila nipalensis), and Upland Buzzard (Buteo hemilasius)] and 11 unique prey species across 10 families and 4 classes. Mammals were the greatest detected prey class with Plateau Pika (Ochotona curzoniae) being the most frequent. Observed Shannon’s and Simpson’s diversity for Upland Buzzard were 1.089 and 0.479, respectively, while expected values were 1.312 ± 0.266 and 0.485 ± 0.086. For Eurasian Eagle Owl, observed values were 1.202 and 0.565, while expected values were 1.502 ± 0.340 and 0.580 ± 0.114. Interspecific dietary niche partitioning between the two species was not detected. Conclusions: Our results demonstrate successful use of DNA metabarcoding for understanding diet via a novel noninvasive sample type to identify common and uncommon species. More work is needed to understand how raptor diets vary locally, and the mechanisms that enable exploitation of similar dietary resources. This approach has wide ranging applicability to other birds of prey, and demonstrates the power of using DNA metabarcoding to study species noninvasively