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.
Three‐dimensional covalent organic frameworks (3D COFs) are promising crystalline materials with well‐defined structures, high porosity, and low density; however, the limited choice of building ...blocks and synthetic difficulties have hampered their development. Herein, we used a flexible and aliphatic macrocycle, namely γ‐cyclodextrin (γ‐CD), as the soft struts for the construction of a polymeric and periodic 3D extended network, with the units joined via tetrakis(spiroborate) tetrahedra with various counterions. The inclusion of pliable moieties in the robust open framework endows these CD‐COFs with dynamic features, leading to a prominent Li ion conductivity of up to 2.7 mS cm−1 at 30 °C and excellent long‐term Li ion stripping/plating stability. Exchanging the counterions within the pores can effectively modulate the interactions between the CD‐COF and CO2 molecules.
Three‐dimensional anionic covalent organic frameworks (COFs) were constructed from aliphatic and flexible macrocyclic γ‐cyclodextrin (γ‐CD) units joined via spiroborate linkages with various counterions. The CD‐COF with Li+ is a good Li ion conductor, and different counterions within the framework lead to different interactions with CO2.
Metal–organic frameworks (MOFs) have received increasing attention as promising electrode materials in supercapacitors (SCs). Yet poor conductivity in most MOFs largely thwarts their capacitance ...and/or rate performance. In this work, an effective strategy was developed to reduce the bulk electric resistance of MOFs by interweaving MOF crystals with polyaniline (PANI) chains that are electrochemically deposited on MOFs. Specifically we synthesized cobalt-based MOF crystals (ZIF-67) onto carbon cloth (CC) and further electrically deposited PANI to give a flexible conductive porous electrode (noted as PANI-ZIF-67-CC) without altering the underlying structure of the MOF. Electrochemical studies showed that the PANI-ZIF-67-CC exhibits an extraordinary areal capacitance of 2146 mF cm–2 at 10 mV s–1. A symmetric flexible solid-state supercapacitor was also assembled and tested. This strategy may shed light on designing new MOF-based supercapacitors and other electrochemical devices.
The coronavirus pandemic has highlighted the capitalist dysfunction showing that considering profit over people can be deadly. The study reveals the LME economies were more responsive toward the ...impact of the disease outbreaks as compared to the CME economies wherein the impact of the disease was moderated by the government involvement. This allows us to draw that the impact of the disease outbreaks can be moderated by increasing the involvement of the government authorities.
Most of the studies on vehicle control and stability are based on cases of known-road lateral slope, while there are few studies on road lateral-slope estimation. In order to provide reliable ...information on slope parameters for subsequent studies, this paper provides a method of structured-road lateral-slope estimation based on machine vision. The relationship between the road lateral slope and the tangent slope of the lane line can be found out according to the image-perspective principle; then, the coordinates of the pre-scan point are obtained by the lane line, and the tangent slope of the lane line is used to obtain a more accurate estimation of the road lateral slope. In the implementation process, the lane-line feature information in front of the vehicle is obtained according to machine vision, the lane-line function is fitted according to an SCNN (Spatial CNN) algorithm, then the lateral slope is calculated by using the estimation formula mentioned above. Finally, the road model and vehicle model are established by Prescan software for off-line simulation. The simulation results verify the effectiveness and accuracy of the method.
Metal–organic frameworks (MOFs), with their well‐defined pores and rich structural diversity and functionality, have drawn a great deal of attention from across the scientific community. However, ...industrial applications are hampered by their intrinsic fragility and poor processability. Stable and resilient MOF devices with tunable flexibility are highly desirable. Herein, we present a solvent‐ and binder‐free approach for producing stable MOF coatings by a unique hot‐pressing (HoP) method, in which temperature and pressure are applied simultaneously to facilitate the rapid growth of MOF nanocrystals onto desired substrates. This strategy was proven to be applicable to carboxylate‐based, imidazolate‐based, and mixed‐metal MOFs. We further successfully obtained superhydrophobic and “Janus” MOF films through layer‐by‐layer pressing. This HoP method can be scaled up in the form of roll‐to‐roll production and may push MOFs into unexplored industrial applications.
Hot off the press: A solvent‐free approach for producing stable MOF coatings through a hot‐pressing (HoP) method is presented. In the HoP method, temperature and pressure are applied simultaneously to facilitate the rapid growth of MOF nanocrystals onto desired substrates. This strategy was proven to be applicable to various MOFs and substrates.
Metal–organic frameworks (MOFs) are a promising class of nanoporous polymeric materials. However, the processing of such fragile crystalline powders into desired shapes for further applications is ...often difficult. A photoinduced postsynthetic polymerization (PSP) strategy was now employed to covalently link MOF crystals by flexible polymer chains, thus endowing the MOF powders with processability and flexibility. Nanosized UiO‐66‐NH2 was first functionalized with polymerizable functional groups, and its subsequent copolymerization with monomers was easily induced by UV light under solvent‐free and mild conditions. Because of the improved interaction between MOF particles and polymer chains, the resulting stand‐alone and elastic MOF‐based PSP‐derived membranes possess crack‐free and uniform structures and outstanding separation capabilities for CrVI ions from water.
Link‐up: A UV‐light‐induced postsynthetic polymerization (PSP) was employed to covalently link crystals of metal–organic frameworks (MOFs) by flexible polymer chains. The obtained MOF‐based membranes are homogeneously structured and show very good separation capacities for the removal of CrVI ions from water.
Low‐density, solid‐state, porous supramolecular organic frameworks are constructed using pillarenes. The frameworks have a honeycomb‐like structure, permanent porosity, high thermal stability, and ...selective and reversible sorption properties toward CO2. The exceptionally selective CO2‐sorption properties (375/1, 339/1) of one framework over N2 and CH4 indicate potential applications in CO2‐capture for post‐combustion power plants and natural gas sweetening.
Researchers have demonstrated that the built environment is associated with mental health outcomes. However, evidence concerning the effects of street environments on mood in fast-growing Asian ...cities is scarce. Traditional questionnaires and interview methods are labor intensive and time consuming and pose challenges for accurately and efficiently evaluating the impact of urban-scale street environments on mood.
This study aims to use street view images and machine learning methods to model the impact of street environments on mood states in a large urban area in Guangzhou, China, and to assess the effect of different street view elements on mood.
A total of 199,754 street view images of Guangzhou were captured from Tencent Street View, and street elements were extracted by pyramid scene parsing network. Data on six mood state indicators (motivated, happy, positive-social emotion, focused, relaxed, and depressed) were collected from 1590 participants via an online platform called Assessing the Effects of Street Views on Mood. A machine learning approach was proposed to predict the effects of street environment on mood in large urban areas in Guangzhou. A series of statistical analyses including stepwise regression, ridge regression, and lasso regression were conducted to assess the effects of street view elements on mood.
Streets in urban fringe areas were more likely to produce motivated, happy, relaxed, and focused feelings in residents than those in city center areas. Conversely, areas in the city center, a high-density built environment, were more likely to produce depressive feelings. Street view elements have different effects on the six mood states. “Road” is a robust indicator positively correlated with the “motivated” indicator and negatively correlated with the “depressed” indicator. “Sky” is negatively associated with “positive-social emotion” and “depressed” but positively associated with “motivated”. “Building” is a negative predictor for the “focused” and “happy” indicator but is positively related to the “depressed” indicator, while “vegetation” and “terrain” are the variables most robustly and positively correlated with all positive moods.
Our findings can help urban designers identify crucial areas of the city for optimization, and they have practical implications for urban planners seeking to build urban environments that foster better mental health.
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•Street view images and machine learning methods were applied to assess the impact of urban-scale streets on residents’ moods.•Streets in urban fringe areas are more likely to produce positive mood than those in city center areas.•High-density built environments are more likely to produce depressive feelings.•“Vegetation” and “terrain” are the variables most robustly and positively correlated with positive moods.•Street view elements have different effects on the moods.
Fatal infectious diseases caused by HIV-1, influenza A virus, Ebola virus, and currently pandemic coronavirus highlight the great need for the discovery of antiviral agents in mechanisms different ...from current viral replication-targeted approaches. Given the critical role of virus–host interactions in the viral life cycle, the development of entry or shedding inhibitors may expand the current repertoire of antiviral agents; the combination of antireplication inhibitors and entry or shedding inhibitors would create a multifaceted drug cocktail with a tandem antiviral mechanism. Therefore, we provide critical information about triterpenoids as potential antiviral agents targeting entry and release, focusing specifically on the emerging aspect of triterpenoid-mediated inhibition of a variety of virus–host membrane fusion mechanisms via a trimer-of-hairpin motif. These properties of triterpenoids supply their host an evolutionary advantage for chemical defense and may protect against an increasingly diverse array of viruses infecting mammals, providing a direction for antiviral drug discovery.
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