Angiotensin-converting enzyme 2 (ACE2) is the cellular receptor for severe acute respiratory syndrome-coronavirus (SARS-CoV) and the new coronavirus (SARS-CoV-2) that is causing the serious ...coronavirus disease 2019 (COVID-19) epidemic. Here, we present cryo-electron microscopy structures of full-length human ACE2 in the presence of the neutral amino acid transporter B
AT1 with or without the receptor binding domain (RBD) of the surface spike glycoprotein (S protein) of SARS-CoV-2, both at an overall resolution of 2.9 angstroms, with a local resolution of 3.5 angstroms at the ACE2-RBD interface. The ACE2-B
AT1 complex is assembled as a dimer of heterodimers, with the collectrin-like domain of ACE2 mediating homodimerization. The RBD is recognized by the extracellular peptidase domain of ACE2 mainly through polar residues. These findings provide important insights into the molecular basis for coronavirus recognition and infection.
The advent of virtual reality (VR) technology has ushered in a new era in language education, offering innovative avenues for immersive and interactive learning experiences. This paper introduces a ...groundbreaking English speaking teaching model designed to harness the power of VR technology. Rooted in the imperative for authentic language practice, our model transports learners into virtual environments meticulously crafted to replicate real-life scenarios. Here, learners engage in conversational interactions, from everyday dialogues to professional exchanges, facilitated by interactive conversational agents. Complementing this immersive experience are adaptive learning algorithms that tailor exercises to individual proficiency levels, alongside multi-modal feedback mechanisms providing comprehensive guidance on pronunciation, intonation, and language usage. Through iterative refinement and a rigorous design methodology, our model seeks to enhance learner engagement, motivation, and proficiency across diverse skill levels. Preliminary pilot studies underscore the model's promise, with participants reporting heightened satisfaction, motivation, and perceived progress in English speaking skills. As we tread further into this innovative domain, future research avenues beckon, including investigations into long-term effectiveness, scalability, and integration into formal education systems. The convergence of VR technology and language education represents a paradigm shift, poised to redefine the dynamics of language acquisition and proficiency in an increasingly interconnected world.
Hybridization of MOFs and polymers Kitao, Takashi; Zhang, Yuanyuan; Kitagawa, Susumu ...
Chemical Society reviews,
06/2017, Letnik:
46, Številka:
11
Journal Article
Recenzirano
Metal-organic frameworks (MOFs) have received much attention because of their attractive properties. They show great potential applications in many fields. An emerging trend in MOF research is ...hybridization with flexible materials, which is the subject of this review. Polymers possess a variety of unique attributes, such as softness, thermal and chemical stability, and optoelectrical properties that can be integrated with MOFs to make hybrids with sophisticated architectures. Hybridization of MOFs and polymers is producing new and versatile materials that exhibit peculiar properties hard to realize with the individual components. This review article focuses on the methodology for hybridization of MOFs and polymers, as well as the intriguing functions of hybrid materials.
This review highlights recent advances in the hybridization of Metal-organic frameworks (MOFs) and polymers.
Graphene is a 2D sheet of sp2 bonded carbon atoms and tends to aggregate together, due to the strong π–π stacking and van der Waals attraction between different layers. Its unique properties such as ...a high specific surface area and a fast mass transport rate are severely blocked. To address these issues, various kinds of 2D holey graphene and 3D porous graphene are either self‐assembled from graphene layers or fabricated using graphene related materials such as graphene oxide and reduced graphene oxide. Porous graphene not only possesses unique pore structures, but also introduces abundant exposed edges and accelerates mass transfer. The properties and applications of these porous graphenes and their composites/hybrids have been extensively studied in recent years. Herein, recent progress and achievements in synthesis and functionalization of various 2D holey graphene and 3D porous graphene are reviewed. Of special interest, electrochemical applications of porous graphene and its hybrids in the fields of electrochemical sensing, electrocatalysis, and electrochemical energy storage, are highlighted. As the closing remarks, the challenges and opportunities for the future research of porous graphene and its composites are discussed and outlined.
Synthesis of 2D and 3D porous graphene is reviewed together with their functionalization with hetero‐atoms and other functional materials. Electrochemical applications of these porous graphene are highlighted in the fields of electrochemical sensing, electrocatalysis, and electrochemical energy storage and conversion. The future research directions and challenges on porous graphene are also discussed and outlined.
In recent years, the development of science and technology in China has greatly affected people’s ways of entertainment. In the traditional industrial model, new industries and Internet industries ...represented by the Internet have emerged, and the Internet video business is an emerging business that has been gradually emerging in the Internet industry in recent years. Moreover, this new teaching method has been gradually noticed in simple education, such as MOOC, I want to self-study network, and Smart Tree, and other online learning websites have sprung up. At present, the epidemic environment makes people pay more attention to this convenient and wide range of online video education. Therefore, we need to evaluate this kind of online video teaching model from the effectiveness of this kind of method and the quality of user experience. This paper takes this as the starting point and chooses the earliest online video platform, MOOC, as the model to establish a set of perfect user experience quality evaluation methods suitable for domestic online video education mode. Considering the data source, the accuracy of the results, and other factors, we chose the industry-leading platform MOOC network as an example. Through the exploration of the MOOC teaching mode in basic education, a member experience evaluation model is established based on fuzzy decision tree algorithm. The experimental results show that the model has high accuracy and high reliability.
App Store Analysis studies information about applications obtained from app stores. App stores provide a wealth of information derived from users that would not exist had the applications been ...distributed via previous software deployment methods. App Store Analysis combines this non-technical information with technical information to learn trends and behaviours within these forms of software repositories. Findings from App Store Analysis have a direct and actionable impact on the software teams that develop software for app stores, and have led to techniques for requirements engineering, release planning, software design, security and testing. This survey describes and compares the areas of research that have been explored thus far, drawing out common aspects, trends and directions future research should take to address open problems and challenges.
Environmental challenges especially air pollution (particulate matter (PM) and toxic gases) pose serious threats to public health globally. Metal–organic frameworks (MOFs) are crystalline materials ...with high porosity, tunable pore size, and rich functionalities, holding the promise for poisonous pollutants capture. Here, nanocrystals of four unique MOF structures are processed into nanofibrous filters (noted as MOFilter) with high MOF loadings (up to 60 wt %). The MOFilters show high PM removal efficiencies up to 88.33 ± 1.52% and 89.67 ± 1.33% for PM2.5 and PM10, respectively, in the hazy environment, and the performance remains largely unchanged over 48 h of continuous filtration. For the first time, the interactions between such porous crystalline material and particulate pollutants were explored. These thin MOFilters can further selectively capture and retain SO2 when exposed to a stream of SO2/N2 mixture, and their hierarchical nanostructures can easily permeate fresh air at high gas flow rate with the pressure drop <20 Pa.
Developing therapeutics against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be guided by the distribution of epitopes, not only on the receptor binding domain (RBD) of the ...Spike (S) protein but also across the full Spike (S) protein. We isolated and characterized monoclonal antibodies (mAbs) from 10 convalescent COVID-19 patients. Three mAbs showed neutralizing activities against authentic SARS-CoV-2. One mAb, named 4A8, exhibits high neutralization potency against both authentic and pseudotyped SARS-CoV-2 but does not bind the RBD. We defined the epitope of 4A8 as the N-terminal domain (NTD) of the S protein by determining with cryo-eletron microscopy its structure in complex with the S protein to an overall resolution of 3.1 angstroms and local resolution of 3.3 angstroms for the 4A8-NTD interface. This points to the NTD as a promising target for therapeutic mAbs against COVID-19.
Endoplasmic reticulum (ER) is a dynamic organelle orchestrating the folding and post-translational maturation of almost all membrane proteins and most secreted proteins. These proteins synthesized in ...the ER, need to form disulfide bridge to acquire specific three-dimensional structures for function. The formation of disulfide bridge is mediated via protein disulfide isomerase (PDI) family and other oxidoreductases, which contribute to reactive oxygen species (ROS) generation and consumption in the ER. Therefore, redox regulation of ER is delicate and sensitive to perturbation. Deregulation in ER homeostasis, usually called ER stress, can provoke unfolded protein response (UPR) pathways with an aim to initially restore homeostasis by activating genes involved in protein folding and antioxidative machinery. Over time, however, activated UPR involves a variety of cellular signaling pathways which determine the state and fate of cell in large part (like autophagy, apoptosis, ferroptosis, inflammation, senescence, stemness, and cell cycle, etc.). This review will describe the regulation of UPR from the redox perspective in controlling the cell survival or death, emphasizing the redox modifications of UPR sensors/transducers in the ER.
Immune checkpoint blockade therapies have shown clinical promise in a variety of cancers, but how tumor-infiltrating T cells are activated remains unclear. In this study, we explore the functions of ...PD-L1 on dendritic cells (DCs), which highly express PD-L1. We observe that PD-L1 on DC plays a critical role in limiting T cell responses. Type 1 conventional DCs are essential for PD-L1 blockade and they upregulate PD-L1 upon antigen uptake. Upregulation of PD-L1 on DC is mediated by type II interferon. While DCs are the major antigen presenting cells for cross-presenting tumor antigens to T cells, subsequent PD-L1 upregulation protects them from killing by cytotoxic T lymphocytes, yet dampens the antitumor responses. Blocking PD-L1 in established tumors promotes re-activation of tumor-infiltrating T cells for tumor control. Our study identifies a critical and dynamic role of PD-L1 on DC, which needs to be harnessed for better invigoration of antitumor immune responses.
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