The rapid accumulation of mutations in the SARS-CoV-2 Omicron variant that enabled its outbreak raises questions as to whether its proximal origin occurred in humans or another mammalian host. Here, ...we identified 45 point mutations that Omicron acquired since divergence from the B.1.1 lineage. We found that the Omicron spike protein sequence was subjected to stronger positive selection than that of any reported SARS-CoV-2 variants known to evolve persistently in human hosts, suggesting a possibility of host-jumping. The molecular spectrum of mutations (i.e., the relative frequency of the 12 types of base substitutions) acquired by the progenitor of Omicron was significantly different from the spectrum for viruses that evolved in human patients but resembled the spectra associated with virus evolution in a mouse cellular environment. Furthermore, mutations in the Omicron spike protein significantly overlapped with SARS-CoV-2 mutations known to promote adaptation to mouse hosts, particularly through enhanced spike protein binding affinity for the mouse cell entry receptor. Collectively, our results suggest that the progenitor of Omicron jumped from humans to mice, rapidly accumulated mutations conducive to infecting that host, then jumped back into humans, indicating an inter-species evolutionary trajectory for the Omicron outbreak.
Hierarchies design of porosity in metal‐organic frameworks (MOFs) has gained significant interest in recent years, and customization of mesoporous sizes in MOFs is still quite challenging. Herein, a ...template‐free method by nucleation‐competition has been developed to realize a near‐linear control of the mesopore sizes (3–13 nm) in the hierarchical MOF UiO‐66(Hf). High selectivity of enzyme adsorption, high activity of bulky‐molecular catalysis, high stability of mesostructure, and extension to other MOFs further prove the success in the potential customization synthesis and applications.
A template‐free method by nucleation‐competition has been developed to realize near‐linear control of the mesopore sizes (3–13 nm) in the hierarchical metal‐organic frameworks UiO‐66(Hf), showing significant performances regarding molecular selectivity, catalytic activity, and mesostructure stability.
To constrain the behavior of Mg isotopes during deep crustal processes and the Mg isotopic composition of the middle and lower continental crust, 30 composite samples from high-grade metamorphic ...terranes and 18 granulite xenoliths were investigated. The composites derive from eight different high-grade metamorphic terranes in the two largest Archean cratons of China, including 13 TTG gneisses, 5 amphibolites, 4 felsic, 4 intermediate, and 4 mafic granulites. They have variable bulk compositions with SiO2 ranging from 45.7 to 72.5%, representative of the middle crust beneath eastern China. The δ26Mg values of these samples vary from -0.40 to +0.12 ppm, reflecting heterogeneity of their protoliths, which could involve upper crustal sediments. The granulite xenoliths from the Cenozoic Hannuoba basalts also have a diversity of compositions with MgO ranging from 2.95 to 20.2%. These xenoliths equilibrated under high temperatures of 800-950°C, corresponding to depths of the lower continental crust (>30 km). They yield a large δ26Mg variation of -0.76 to -0.24 ppm. The light Mg isotopic compositions likely result from interactions with isotopically light metamorphic fluids, probably carbonate fluids. Together with previously reported data, the average δ26Mg values of the middle and lower continental crusts are estimated to be -0.21±0.07 ppm and -0.26±0.06 ppm, respectively. The bulk continental crust is estimated to have an average δ26Mg of -0.24±0.07 ppm, which is similar to the average of the mantle. The large Mg isotopic variation in the continental crust reflects the combination of several processes, such as continental weathering, involvement of supracrustal materials in the deep crust, and fluid metasomatism.
The radial conjugated π‐system of cycloparaphenylenes (CPPs) makes them intriguing fluorophores and unique supramolecular hosts. However, the bright photoluminescence (PL) of CPPs was limited to the ...blue light and the supramolecular assembly behavior of large CPPs was rarely investigated. Here we present the synthesis of tetra‐benzothiadiazole‐based 12cycloparaphenylene (TB12CPP), which exhibits a lime to orange PL with an excellent quantum yield up to 82 % in solution. The PL quantum yield of TB12CPP can be further improved to 98 % in polymer matrix. Benefiting from its enlarged size, TB12CPP can accommodate a fullerene derivative or concave–convex complexes of fullerene and buckybowl through the combined π–π and C−H⋅⋅⋅π interactions. The latter demonstrates the first case of a ternary supramolecule of CPPs.
A benzothiadiazole‐based 12cycloparaphenylene (TB12CPP) is obtained and characterized. TB12CPP exhibits a lime to orange emission with a quantum yield up to 98 %, ranking it as one of the brightest CPPs. As a supramolecular host, TB12CPP is bright as well, showing adaptable ring structure. A ternary assembly between TB12CPP, fullerene, and buckybowl is realized.
Aims and objectives
To explore nurses' views regarding implementing advance care planning for older people.
Background
Advance care planning is recommended as a way for older people to discuss their ...future care with family members and health professionals. Nurses play key roles in the process of advance care planning, including ensuring that patients are informed of their rights and that decisions are known to, and respected by, the health care team. Thus, understanding of nurses' experiences and perspectives regarding implementing advance care planning for older people is a significant topic for review.
Design
Qualitative meta‐synthesis.
Methods
Four databases including CINAHL plus, Medline EBSCOhost, EMBASE, and PsycINFO were searched, and 1844 articles were initially screened. Finally, 18 articles were critically appraised and a thematic synthesis was undertaken.
Results
Four themes were identified regarding implementation of advance care planning: perceived disadvantages and advantages of advance directives; nurses' responsibility and roles; facilitators and barriers; and nurses' needs and recommendations. Nurses felt that advance directives provided more advantages than disadvantages. Nurses generally believed that they were well positioned to engage in advance care planning conversations. Nurses perceived barriers relating to older people, families, environment, time, culture, cost, language and knowledge of health care teams with regard to advance care planning. In nurses' needs, education and support were highlighted.
Conclusions
This study provides useful knowledge for implementing advance care planning through illustrating nurses' experiences and perspectives. The results showed that nurses were more concerned about barriers in relation to working environment, teamwork, time and knowledge of health care team members than older people's characteristics, when implementing advance care planning.
Relevance to clinical practice
The findings provide nurses and administrators with information to develop related policies and education. Additionally, the appointment of nurses to formal roles related to advance care planning is appropriate and warranted.
Production of renewable hydrogen energy by water electrolysis is an effective method to reduce carbon emissions. In comparison to freshwater, seawater is a more suitable raw material for electrolysis ...thanks to its abundant reserves. However, the reported catalysts are not suitable for large-scale commercial application as a result of the reduction of catalyst stability and activity within complex natural seawater. To better promote the rational design of electrocatalysts and tackle the challenges of seawater splitting, this mini review summarized recent advances in rational design electrocatalysts for seawater splitting, including constructing a hierarchical structure, decorating a corrosion resistance layer, and introducing a charge redistribution within the system. Afterward, a perspective in the development of large-scale seawater electrolysis for hydrogen production is also proposed.
Carbon‐based nanomaterials have been widely utilized in catalysis and energy‐related fields due to their fascinating properties. However, the controllable synthesis of porous carbon with refined ...morphology is still a formidable challenge due to inevitable aggregation/fusion of resulted carbon particles during the high‐temperature synthetic process. Herein, a hierarchically oriented carbon‐structured (fiber‐like) composite is fabricated by simultaneously taking advantage of a confined pyrolysis strategy and disparate bond environments within metal–organic frameworks (MOFs). In the resultant composite, the oriented carbon provides a fast mass (molecule/ion/electron) transfer efficiency; the doping‐N atoms can anchor or act as active sites; the mesoporous SiO2 (mSiO2) shell not only effectively prevents the derived carbon or active metal nanoparticles (NPs) from aggregation or leaching, but also acts as a “polysulfide reservoir” in the Li–S batteries to suppress the “shuttle” effect. Benefiting from these advantages, the synthesized composite Pd@NDHPC@mSiO2 (NDHPC means N‐doped hierarchically porous carbon) exhibits extremely high catalytic activity and stability toward the one‐pot Knoevenagel condensation–hydrogenation reaction. Furthermore, the oriented NDHPC@mSiO2 manifests a boosted capacity and cycling stability in Li–S batteries compared to the counterpart that directly pyrolyzes without silica protection. This report provides an effective strategy of fabricating hierarchically oriented carbon composites for catalysis and energy storage applications.
An N‐doped oriented carbon‐structured (fiber‐like) composite with hierarchical pore and ultrafine Pd nanoclusters is fabricated by simultaneously taking advantage of the confined pyrolysis strategy and disparate bond environments within metal–organic frameworks (MOFs). The synthesized composite Pd@NDHPC@mSiO2 manifests extremely high catalytic activity toward tandem catalysis and much boosted cycling stability in Li–S batteries.
Although heptagons are widely found in graphenic materials, the precise synthesis of nanocarbons containing heptagons remains a challenge, especially for the nanocarbons containing ...multiple‐heptagons. Herein, we show that photo‐induced radical cyclization (PIRC) can be used to synthesize multi‐heptagon‐embedded nanocarbons. Notably, a nanographene containing six heptagons (1) was obtained via a six‐fold cascade PIRC reaction. The structure of 1 was clearly validated and showed a Monkey‐saddle‐shaped conformation. Experimental bond analysis and theoretical calculations indicated that the heptagons in 1 were non‐aromatic, whereas the peripheral rings were highly aromatic. Compared to planar nanographene with the same number of π electrons, 1 had a similar optical gap due to a compromise between the decreased conjugation in the wrapped structure and enhanced electronic delocalization at the rim. Electrochemical studies showed that 1 had low‐lying oxidation potentials, which was attributed to the nitrogen‐doping.
Photo‐induced radical cyclization was used in the synthesis of nanocarbons with embedded heptagons, providing a new approach towards nanocarbons with novel topologies. The nanographene reported herein bears six heptagons, representing the nanocarbon containing the largest number of heptagons by organic synthesis reported to date. The embedded heptagons distort the graphene core into a Monkey‐saddle‐shaped conformation.
The Sustainable Urban Land Use Policy is a critical component of sustainable land use in China, aiming to improve the urban land use efficiency, increase land output, protect the land ecological ...environment and realize the sustainable utilization of urban land resources. As part of the strategy for sustainable urbanization, the Sustainable Urban Land Use Policy has been implemented in some cities for years. To evaluate the effectiveness and reveal the future direction of development of this policy, it is essential to analyze this policy in the framework of sustainable urbanization. It is possibly a reliable measure to evaluate the effectiveness of this policy by assessing the contribution of sustainable urban land use policies to sustainable urbanization strategies and the trend of contribution over time. This paper measured the degree of sustainable urbanization and sustainable urban land use with necessary Control Variables and Instrument Variables using panel data of 31 provincial capital cities from 2000 to 2008 and 2009 to 2014. The regression results showed that the Sustainable Urban Land Use Policy had a significant positive effect on China's sustainable urbanization and the effectiveness improved after 2008. From the aspect the mechanism, the contribution of this policy to sustainable urbanization was to promote economic growth, thereby, to improve the social welfare. In contrast, the role of promoting urban development potential and the decreasing urban resource consumption was not so significant. Therefore, while maintaining the existing achievements through macro-control, reducing resource consumption, increase land use intensity, improve urban development potential are the further goals of land use policy in the future.
The rapid increase in urbanization has brought about a great deal of ecological problems, and thus the systematic protection of the environment is vital. Ecological security patterns are important ...for maintaining regional ecological stability and sustainable urban development. Human disturbance is a key factor affecting the stability and sustainable development of ecosystems. This paper constructs an ecological security pattern and evaluates the degree of human disturbance in Fuzhou City. Through a comprehensive analysis of both of these factors, the ecological priority restoration areas in Fuzhou were identified. The study shows that (1) there are 40 ecological source areas in Fuzhou, with a total area of 4556.48 km2; 83 ecological corridors, with a total distance of 179.33 km; and 30 ecological nodes. (2) The human disturbance degree score in the study area is between 0 and 0.8. The degree of human disturbance forms two larger major cores in Cangshan District, Gulou District, and Fuqing City. (3) The scores for the degree of human disturbance with ecological sources range from 0 to 0.42. The high-priority areas in the study area are distributed at the edges of ecological sources and form two high-scoring aggregation areas in Fuqing City and Jinan District. These corridors have a high degree of human disturbance with scores between 0 and 0.56. The I and II priority areas are mostly found in longer corridors in Fuqing City and Cangshan District near coastal or urban centers, and the III priority areas are mainly distributed in ecological corridors near the inland. The human disturbance degree scores of the nodes range from 0.01 to 0.27, and the nodes with higher grades were mainly distributed in the northeast, southeast, northwest and southwest of the study area.
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