Chiral sensors have attracted growing interest due to their application in health monitoring. However, rational design of wearable logic chiral sensors remains a great challenge. In this work, a dual ...responsive chiral sensor RT@CDMOF is prepared through in situ self-assembly of chiral γ-cyclodextrin metal-organic framework (CDMOF), rhodamine 6G hydrazide (RGH), and tetracyanovinylindane (TCN). The embedded RGH and TCN inherit the chirality of host CDMOF, producing dual changes both in fluorescence and reflectance. RT@CDMOF is explored as a dual channel sensor for chiral discrimination of lactate enantiomers. Comprehensive mechanistic studies reveal the chiral binding process, and carboxylate dissociation is confirmed by impedance and solid-state
H nuclear magnetic resonance (NMR). A flexible membrane sensor is successfully fabricated based on RT@CDMOF for wearable health monitoring. Practical evaluation confirms the potential of fabricated membrane sensor in point-of-care health monitoring by indexing the exercise intensity. Based on above, a chiral IMPLICATION logic unit can be successfully achieved, demonstrating the promising potential of RT@CDMOF in design and assembly of novel smart devices. This work may open a new avenue to the rational design of logic chiral sensors for wearable health monitoring applications.
By incorporating an anthracene moiety into a framework, a multiresponsive luminescent metal–organic framework (1) has been synthesized, which exhibits both direct chemiluminescence (CL) and dual ...tunable photoluminescence. By utilizing the CL, 1 has been explored as a selective visual sensor for hydrogen peroxide. Moreover, 1 also exhibits tunable fluorescence response toward different analytes. For electron‐rich aromatics, “turn‐on” and “turn‐off” responses can be simply switched by varying the excitation wavelength. For nitroaromatics, 1 exhibits novel linear quantitative quenching response. Density functional theory (DFT) calculations and experiments have been carried out to study the unique fluorescence response. The multiple luminescence properties and dual tunable sensing response indicate that incorporating anthracene moieties into frameworks should be a promising strategy to develop unprecedented luminescent materials with remarkable sensing properties.
A 3D metal‐organic framework (MOF) consisting of an anthracene moiety is reported, which is the first example of a MOF exhibiting both direct chemiluminescence and dual tunable photoluminescence. The material is explored as a selective visual sensor for probing hydrogen peroxide, a dual sensor for aromatics, and a quantitative sensor for nitroaromatics.
Glassy and liquid state metal–organic frameworks (MOFs) are emerging type of materials subjected to intense research for their rich physical and chemical properties. In this report, we obtained the ...first glassy MOF that involves metal‐carboxylate cluster building units via multi‐stage structural transformations. This MOF is composed of linear Mn3(COO)6 node and flexible pyridyl‐ethenylbenzoic linker. The crystalline MOF was first perturbed by vapor hydration and thermal dehydration to give an amorphous state, which can go through a glass transition at 505 K into a super‐cooled liquid. The super‐cooled liquid state is stable through a wide temperature range of 40 K and has the largest fragility index of 105, giving a broad processing window. Remarkably, the super‐cooled liquid can not only be quenched into glass, but also recrystallize into the initial MOF when heated to a higher temperature above 558 K. The mechanism of the multi‐stage structural transformations was studied by systematic characterizations of in situ X‐ray diffraction, calorimetry, rheological, spectroscopic and pair‐distribution function analysis. These multi‐stage transformations not only represent a rare example of high temperature coordinative recognition and self‐assembly, but also provide new MOF processing strategy through crystal‐amorphous‐liquid‐crystal transformations.
The first MOF glass composed of metal‐carboxylate cluster building units is vitrified by multi‐stage transformations: The crystalline MOF is amorphized by vapor hydration and thermal dehydration, goes through a glass transition to enter a super‐cooled liquid state, and recrystallizes into the initial structure. These multi‐stage transformations are a rare example of high‐temperature coordinative recognition and self‐assembly.
Surface reconstruction that produces real active species for catalytic reactions generally occurs during electrocatalytic water splitting, but overcoming the reconstruction level‐mass ...activity‐stability trade‐off is a grand challenge. A cation‐doping in conjunction with a geometrical topology strategy is proposed to concurrently realize deep reconstruction and self‐optimization of FeNi phosphide nanoarrays during an electrochemical activation process. The doped Zn cation induces a deep reconstruction of FeNiP@Fe2P precatalyst by continuously dissolving Fe2P and re‐depositing as amorphous FeOOH that solders Ni2P nanoparticles, forming small ultra‐thin nanosheets with abundant amorphous‐crystalline interfaces for structural stability. Moreover, multichannel topology exhibits an unusual ability to optimize their morphology via finally evolving into multi‐microchannel tubular nanoarrays comprising of interconnected‐nanosheets with a very loose structure for enhanced electrolyte permeability, mass transfer, and accessibility of active sites. The reconstructed Zn‐Ni2P/FeOOH superstructure catalysts reach 10 mA cm−2 current density at an ultra‐low overpotential of 11 mV for hydrogen evolution reactions (HER). Impressively, when assembled as a two‐electrode cell with Zn‐FeNiP@Zn‐Fe2P as anode and Zn‐Ni2P/FeOOH as cathode, it delivers current densities of 10 mA cm−2 at a record low cell voltage of 1.40 V. This strategy provides a novel avenue to promote reconstruction for achieving high catalytic performance.
A cation‐doping in conjunction with a geometrical topology strategy is developed to concurrently realize deep reconstruction during the hydrogen evolution reactions (HER) electrochemical activation process. The reconstructed Zn‐Ni2P/FeOOH superstructure catalysts reach 10 mA cm−2 current density at an ultra‐low overpotential of 11 mV for HER.
MADS transcription factors are involved in the regulation of fruit development and carotenoid metabolism in plants. However, whether and how carotenoid accumulation is regulated by algal MADS are ...largely unknown. In this study, we first used functional complementation to confirm the functional activity of phytoene synthase from the lutein‐rich Dunaliella sp. FACHB‐847 (DbPSY), the key rate‐limiting enzyme in the carotenoid biosynthesis. Promoters of DbPSY and DbLcyB (lycopene β‐cyclase) possessed multiple cis‐acting elements such as light‐, UV‐B‐, dehydration‐, anaerobic‐, and salt‐responsive elements, W‐box, and C‐A‐rich‐G‐box (MADS‐box). Meanwhile, we isolated one nucleus‐localized MADS transcription factor (DbMADS), belonging to type I MADS gene. Three carotenogenic genes, DbPSY, DbLcyB, and DbBCH (β‐carotene hydroxylase) genes were upregulated at later stages, which was well correlated with the carotenoid accumulation. In contrast, DbMADS gene was highly expressed at lag phase with low carotenoid accumulation. Yeast one‐hybrid assay and dual‐luciferase reporter assay demonstrated that DbMADS could directly bind to the promoters of two carotenogenic genes, DbPSY and DbLcyB, and repress their transcriptions. This study suggested that DbMADS may act as a negative regulator of carotenoid biosynthesis by repressing DbPSY and DbLcyB at the lag phase, which provide new insights into the regulatory mechanisms of carotenoid metabolism in Dunaliella.
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•Physical immobilization of cellulase onto MOF was achieved for the first time.•>85% of maximum activity of immobilized cellulase can be maintained at 80 °C.•>90% of maximum activity ...can be maintained between pHs 3–6 of hydrolysis.•>72% of residual activity was maintained after 10 cycles.•>65% of maximum activity could be reserved after 30 days of storage.
Developing a new cellulase-MOF composite system with enhanced stability and reusability for cellulose hydrolysis was aimed. Physical adsorption strategy was employed to fabricate two cellulase composites, and the activity of composite was characterized by hydrolysis of carboxymethyl cellulose. The NH2 functionalized UiO-66-NH2 MOF exhibited higher protein loading than the precursor UiO-66, due to the extra anchor sites of NH2 groups. The immobilized cellulase showed enhanced thermostability, pH tolerance and lifetime. The maximum activity attained at 55 °C could be kept 85% when used at 80 °C, and the residual activities were 72% after ten cycles and 65% after 30 days storage. The abundant NH2 and COOH groups of MOF adsorb cellulase and enhance its stability, and the resulted heterogeneity offered the opportunity of recovering composite via mild centrifuge. The findings suggest the promising future of developing cellulase-MOF composite with ultrahigh activities and stabilities for practical application.
Cytokine storm and multi-organ failure are the main causes of SARS-CoV-2-related death. However, the origin of excessive damages caused by SARS-CoV-2 remains largely unknown. Here we show that the ...SARS-CoV-2 envelope (2-E) protein alone is able to cause acute respiratory distress syndrome (ARDS)-like damages in vitro and in vivo. 2-E proteins were found to form a type of pH-sensitive cation channels in bilayer lipid membranes. As observed in SARS-CoV-2-infected cells, heterologous expression of 2-E channels induced rapid cell death in various susceptible cell types and robust secretion of cytokines and chemokines in macrophages. Intravenous administration of purified 2-E protein into mice caused ARDS-like pathological damages in lung and spleen. A dominant negative mutation lowering 2-E channel activity attenuated cell death and SARS-CoV-2 production. Newly identified channel inhibitors exhibited potent anti-SARS-CoV-2 activity and excellent cell protective activity in vitro and these activities were positively correlated with inhibition of 2-E channel. Importantly, prophylactic and therapeutic administration of the channel inhibitor effectively reduced both the viral load and secretion of inflammation cytokines in lungs of SARS-CoV-2-infected transgenic mice expressing human angiotensin-converting enzyme 2 (hACE-2). Our study supports that 2-E is a promising drug target against SARS-CoV-2.
Separation of acetylene and ethylene is an important industrial process because both compounds are essential reagents for a range of chemical products and materials. Current separation approaches ...include the partial hydrogenation of acetylene into ethylene over a supported Pd catalyst, and the extraction of cracked olefins using an organic solvent; both routes are costly and energy consuming. Adsorption technologies may allow separation, but microporous materials exhibiting highly selective adsorption of C(2)H(2)/C(2)H(4) have not been realized to date. Here, we report the development of tunable microporous enantiopure mixed-metal-organic framework (M'MOF) materials for highly selective separation of C(2)H(2) and C(2)H(4). The high selectivities achieved suggest the potential application of microporous M'MOFs for practical adsorption-based separation of C(2)H(2)/C(2)H(4).
Coke plays a key role as the skeleton of the charge column in BF. The gas path formed by the coke layer in the BF has a decisive influence on gas permeability. At high temperatures, the interface ...between coke and ore undergoes a melting reaction of coke and a reduction reaction of ore. The better the reducibility of the ore, the more conducive it is to the coupling reaction of ore and coke. The melting loss reaction of coke becomes more intense, and the corresponding strength of coke will decrease, which will affect the permeability of the blast furnace and is not conducive to the smooth operation of the blast furnace. Especially with a deterioration in iron ore quality, BF operation faces severe challenges, which makes it necessary to find an effective way to strengthen BF operation. In this study, a melting-dropping furnace was used to develop and clarify the high-temperature interaction between coke and iron ores with different layer thicknesses. The influencing factors were studied by establishing a gas permeability mathematical model and observing the metallographic microscope images of samples after the coke solution loss reaction. The relationships between coke layer thickness, distribution of gas flow, and pressure drop were obtained. The results showed that, under certain conditions, the gas permeability property of a furnace burden has been improved after the coke layer thickness increased. Upon observing the size of coke particles at the interface reaction site, the degree of melting loss reaction can be determined. A smaller particle size indicates more melting loss reaction. A dripping eigenvalue for molten metal was introduced to evaluate the dynamic changes in the comprehensive dripping properties of molten metal of furnace burden, which showed that the dripping eigenvalue for the molten metal could deteriorate because of the unruly thickness and the coke layer thickness should be limited through considering the operational indicators of the blast furnace.
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•Chrysanthemum-like C@Cu2O/CuO was fabricated via conditioned calcination of HKUST-1.•Promising stability with remarkable H2 evolution rate of 26.7 mmol g−1h−1 was achieved.•High ...external quantum efficiency of 52.4% nm was obtained at 425 nm.•Synergistic effect of the three components was revealed.
Hydrogen production from photocatalytic water splitting by non-noble-metal photocatalysts is considered to be the most promising solution to the world energy crisis issues. Herein, a chrysanthemum-like crystalline C@Cu2O/CuO composite with remarkable photochemical water reduction activity has been successfully fabricated via conditioned calcinations of the Cu(II) based MOF. Under visible light irradiation, Cu2O/CuO/C-350 gives a remarkable H2 evolution rate of 26.7 mmol g−1h−1 with high external quantum efficiency of 52.4% at 425 nm. The unique morphology, significantly improved charge carrier separation and synergistic effects of the composite system should be responsible for the excellent photocatalytic activity. To get further evidence about the origin of the improved photoactivity of the Cu2O/CuO/C-350, a series of characterization has been carried out. These findings propose a new unexplored avenue for the fabrication of highly active and low cost photocatalyst for practical H2 generation via photochemical water reduction.
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