Spiroxins A, C, and D are metabolites that have been identified in the marine fungal strain LL‐37H248. Their unique polycyclic structures and intriguing biological activities make them attractive ...targets for the synthetic community. Based on a scalable enantioselective epoxidation of 5‐substituted naphthoquinone, an oxidation/spiroketalization cascade, ortho‐selective chlorination of the phenol unit, and oxime‐ester‐directed acetoxylation, an enantioselective total synthesis of (−)‐spiroxins A and C and the first total synthesis of (−)‐spiroxin D have been achieved.
Based on a scalable enantioselective epoxidation of 5‐substituted naphthoquinone, an oxidation/spiroketalization cascade, the ortho‐selective chlorination of the phenol unit, and oxime‐ester‐directed acetoxylation, a divergent and enantioselective synthetic route to (−)‐spiroxins A and C and the first total synthesis of (−)‐spiroxin D have been achieved.
The fabrication strategies, characterizations, photocatalytic performances and the corresponding mechanism of some typical TiO2/MOF composites were highlighted and reviewed. Also, the prospective and ...challenges of TiO2/MOF composites as photocatalysts were declared.
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•The facile fabrication strategies of TiO2/MOF composites were highlighted.•The enhanced photocatalytic activities of TiO2/MOF composites were reviewed.•The possible photocatalysis mechanisms over TiO2/MOF composites were summed.•The composite fabrication is a good approach to combine the merits of TiO2 and MOF.•The prospective of TiO2/MOF composites as photocatalysts is declared.
Up to now, titanium dioxide (TiO2) is the most established semiconductor photocatalyst, which is used to achieve photocatalytic H2 evolution, pollutants degradation, CO2 reduction, and N2 reduction under UV light irradiation. TiO2 as photocatalyst is always under the spotlight due to its unique properties like outstanding thermal/chemical stability, wide bandgap with suitable band edge, low cost, non-toxicity, and corrosion resistance. To further improve the photocatalytic activity of TiO2, the versatile and porous metal-organic frameworks (MOFs) can be introduced to constructionTiO2/MOF composites, which can accomplish the enhanced light absorption performance and improved electron-hole pair separation. With this review, the fabrication strategies, characterizations techniques, photocatalytic activities and the mechanisms of some selected TiO2/MOF composites were reviewed and highlighted. The last but not the least, the outlooks and challenges of TiO2/MOF composites as photocatalysts for energy conversion and environment remediation are proposed.
Bifunctional Bi12O17Cl2/MIL-100(Fe) composite (BMx) was firstly constructed via facile ball-milling method. The optimal BM200 was highly efficient for Cr(VI) sequestration and activation of ...persulfate (PS) for bisphenol A (BPA) decomposition under white light illumination, which was much more remarkable than the pristine MIL-100(Fe) and Bi12O17Cl2, respectively. Furthermore, the photocatalytic reduction efficiency can be significantly improved via the addition of some green small organic acids (SOAs). As well, the BPA degradation can be achieved over an extensive initial pH range of 3.0–11.0. When the PS concentration increased to more than 2.0 mM, the BPA degradation efficiency decreased due to the SO4−• self-scavenging effect. It was also found that the co-existence of inorganic anions like H2PO4−, HCO3−, SO42−, Cl− and NO3− could decelerate the BPA degradation. The excellent photocatalytic Cr(VI) reduction and persulfate activation performances originated from both MIL-100(Fe) with excellent PS activation ability and Bi12O17Cl2 with a favorable band position, which not only enabled the efficient separation of charges but also accelerated the formation of SO4−• radicals. The BM200 displayed prominent stability and recyclability. More importantly, the credible degradation pathway was proposed based on UHPLC-MS analysis and DFT calculation. This research revealed that the Fe-based MOFs/bismuth-rich bismuth oxyhalides (BixOyXz, X = Cl, Br and I) composites possessed great potential in wastewater remediation.
Bismuth-rich Bi12O17Cl2/MIL-100(Fe) composites were firstly fabricated to achieve efficient Cr(VI) sequestration and BPA degradation with the addition of persulfate PS under white light illumination. Display omitted
•Bi12O17Cl2/MIL-100(Fe) (BMx) was constructed by facile ball-milling method.•BM200 composite was an efficient photocatalyst for Cr(VI) and BPA cleanup.•BM200/light/PS system exhibited synergistic effect in BPA degradation.•BM200 showed good reusability and high stability.•DFT calculation with high Fukui index interpreted the easy-attacking sites on BPA.
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•CoM/TNTs showed high ACE degradation efficiency after PMS activation.•Efficient PMS activation was due to the synergic effect of Co(OH)2 and TNTs.•TNTs with abundant surface –OH ...facilitated formation of CoOH+.•PES analysis well explained the higher feasibility of Co(OH)+ on PMS activation.•ACE atoms with high Fukui index are active sites for electrophilic attack.
Pharmaceuticals and personal care products (PPCPs) are of great concern due to their increasing health effects, so advanced treatment technologies for PPCPs removal are urgently needed. In this study, titanate nanotubes decorated Co(OH)2 hollow microsphere (CoM/TNTs) composites were synthesized by a two-step solvothermal method, and used to activate peroxymonosulfate (PMS) through heterogenous catalysis for acetaminophen (ACE) degradation in water. The optimum material (CoM/TNTs0.5) activated PMS system exhibited high ACE removal efficiency and quick kinetic, as 93.0% ACE was degraded even within 10 min. The two components in CoM/TNTs showed a synergetic effect on PMS activation for radicals production: Co(OH)+ from CoM was the primary active species to active PMS, while TNTs could offer abundant –OH groups for Co(OH)+ formation. Density functional theory (DFT) calculation further interpreted the mechanism of Co(OH)+ for PMS activation by means of reaction potential energy surface (PES) analysis. Both the scavenger quenching tests and electron paramagnetic resonance analysis revealed that the sulfate radical (SO4-·) played a dominant role in ACE degradation. Moreover, DFT calculation also suggested that the ACE atoms with high Fukui index (f-) represented the active sites for electrophilic attack by SO4-·. The toxicity analysis based on quantitative structure-activity relationship (QSAR) verified the reduced toxicity of transformation products. Furthermore, CoM/TNTs also had good reusability and stability over five cycles. This work provides deep insights into the reaction mechanisms of radical production and organics attack in cobalt-based PMS activation system.
HiC-Pro is an optimized and flexible pipeline for processing Hi-C data from raw reads to normalized contact maps. HiC-Pro maps reads, detects valid ligation products, performs quality controls and ...generates intra- and inter-chromosomal contact maps. It includes a fast implementation of the iterative correction method and is based on a memory-efficient data format for Hi-C contact maps. In addition, HiC-Pro can use phased genotype data to build allele-specific contact maps. We applied HiC-Pro to different Hi-C datasets, demonstrating its ability to easily process large data in a reasonable time. Source code and documentation are available at http://github.com/nservant/HiC-Pro .
For broad-spectrum adsorption and capture toward cationic metal ions, a facile strategy was adopted to fabricate defective SO3H-MIL-101(Cr) (SS-SO3H-MIL-101(Cr)-X, X = 2, 3, 4) with enhanced ...vacancies using seignette salt (SS) as the modulating agent. The boosted adsorption performances of SS-SO3H-MIL-101(Cr)-X toward eight different ions, including Ag+, Cs+, Pb2+, Cd2+, Ba2+, Sr2+, Eu3+ and La3+ in both individual component and mixed component systems, could be ascribed to the effective mass transfer resulting from the exposure of defective sites. Especially, the optimal SS-SO3H-MIL-101(Cr)−3 could remove all the selected metal cations to below the permissible limits required by the World Health Organization (WHO) in the continuous-flow water treatment system. Furthermore, SS-SO3H-MIL-101(Cr)−3 exhibited good adsorption capacity (189.6 mg·g−1) toward Pb2+ under neutral condition and excellent desorption recirculation performance (removal efficiency > 95% after 5 cycles). Moreover, the adsorption mechanism involved the electrostatic adsorption and coordinative interactions resulting from complexation between the adsorption active sites and targeted cations (like Cr-O-M and S-O-M), which were explored systematically via both X-ray photoelectron spectroscopy (XPS) determination and density functional theory (DFT) calculations. Overall, this work provided guidance for modulating SS-SO3H-MIL-101(Cr)-X to promote its potential application in widespread metal cations removal from wastewater.
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•Defective SO3H-MIL-101(Cr) with abundant vacancies was obtained.•SS-SO3H-MIL-101(Cr)-X exhibited adsorption activity toward various metal cations.•The sorption mechanisms were clarified via characterizations and DFT calculations.
In the aging rehabilitation landscape design of community parks, the crack detection of landscape architecture is very important, which is related to the beauty and safety of landscape architecture. ...In order to improve the poor effect of current landscape building crack detection methods, an intelligent landscape building crack detection model based on improved YOLOv4 is proposed. Aiming at the inadequacy of information feature extraction in YOLOv4 algorithm, the coordinate attention module with extended convolution structure optimization is adopted to optimize it. Aiming at the defect that YOLOv4 algorithm has poor information feature utilization rate of shallow position, an improved K-means algorithm is designed to determine the optimal size of prior frame, so as to improve the performance of the algorithm. The performance of the algorithm is improved. Finally, combined with the above content, an intelligent detection model of landscape building cracks based on improved YOLOv4 is constructed. The results verify that the fitting degree of the model is 0.986, which is 0.008 and 0.016 higher than that of the CRF-CNN and Faster-RCNN models, respectively. The F1 value is 0.951, 0.10–0.12 higher than the two models. The accuracy was 98.26%, 0.47%-0.51% higher than the two models. Recall value was 96.44%, which was 0.47%-0.51% higher than that of the two models. The AUC value is 0.988, which is 0.009–0.016 higher than the two models. To sum up, the model built in the study can detect the cracks in landscape architecture with high accuracy and efficiency, and improve the safety and beauty of the landscape. Meanwhile, this model can assist in the design of aging rehabilitation landscape in community parks.
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•The immobilized MIL-88A(Fe) onto cotton fibers (MC) was prepared.•MC was used to achieve efficient and long-term elimination of tetracyclines matrix.•A fixed bed reactor is ...constructed from MC in a home-made annular setup.•MC displayed boosted long-term stability in both batch and fixed bed tests.
This work demonstrates the successful immobilization of MIL-88A(Fe) MOF on cotton fibers to fabricate MIL-88A(Fe)/cotton fibers (MC) by an eco-friendly method. The prepared MC is used to activate peroxydisulfate for eliminating multiple tetracycline antibiotics, such as oxytetracycline (OTC), tetracycline (TTC), and chlortetracycline (CTC) in simulated wastewater under UV-light irradiation. The photoactivated sulfate radical-advanced oxidation processes (SR-AOPs) towards the removal of tetracycline antibiotics matrix (initial concentration of 10.0 mg/L) using MC were initially investigated using a batch method. The results reveal that 97.5% OTC, 95.2% TTC, and 100.0% CTC can be degraded in the MC/UV/PDS system in the presence of 2 g/L of MC and 1 mM of PDS. The degradation pathways of OTC, TTC, and CTC were clarified via liquid chromatography-mass spectrometry analysis and DFT calculations. The quantitative structure–activity relationship analysis shows that the tetracycline antibiotics are transformed into their corresponding intermediates with lower toxicity within 8.0 min. A self-designed fixed bed reactor, in which the MC was packed into the annular channel, was adopted to test the long-term operation possibility of the MC in the continuous photoactivated SR-AOP system. The findings demonstrate that the whole antibiotics matrix can be removed completely within 22 h. This work is the first to demonstrate the use of MOFs as catalysts for SR-AOP to achieve continuous purification of simulated wastewater. The findings highlight a new possibility for the use of MOFs in large-scale wastewater treatment over.
Cephalotaxus diterpenoids represent a class of attractive natural products with diverse chemical structures and valuable biological activities. The Construction of tetracyclic core skeleton plays an ...important role in synthesizing these compounds. We report here the development of diastereoselective Pauson‐Khand reactions as an effective strategy to the core structure, which enabled the total synthesis of (+)‐3‐deoxyfortalpinoid F, (+)‐fortalpinoid A, and (+)‐cephinoid H.
An effective strategy to the tetracyclic core skeleton of Cephalotaxus diterpenoids has been developed based on diastereoselective Pauson‐Khand reactions. It builds up a good foundation for our further work on synthesis of these natural products.
Arsenic contamination has attracted worldwide concerns, owing to its toxicity and severe threat to human and environment. It is urgent to develop efficient adsorbents to remove arsenic pollutants. ...Within this paper, both pristine MIL-88A(Fe) and MIL-88A(Fe) decorated on cotton fibers were successfully fabricated using an eco-friendly method. The pristine MIL-88A(Fe) displayed outstanding adsorption performances towards four selected arsenic pollutants, in which the adsorption capacities toward As(III), As(V), ROX and ASA were 126.5, 164.0, 261.4 and 427.5 mg g−1, respectively. Additionally, MIL-88A(Fe) exhibited excellent removal efficiencies in a wide pH range and with the presence of different co-existing ions. It was proposed that the coordinative interactions of As–O–Fe between arsenic pollutants and MIL-88A(Fe) contributed to the superior adsorption performances. Furthermore, two MIL-88A(Fe)/cotton fibers composites were synthesized by both post synthesis (MC-1) and in-situ synthesis (MC-2), which demonstrated identically outstanding adsorption activities toward four selected arsenic pollutants. MC-1 and MC-2 enhanced the stability and reusability of MIL-88A(Fe), which was challenging issues of pristine MIL-88A(Fe) powder. Additionally, the fixed-bed column packed by MC-1 or MC-2 can continuously eliminate arsenic pollutants from the water flow. This work provided a new possibility of metal-organic frameworks to accomplish potentially large-scale application to purify the arsenic-contaminated water.
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•MIL-88A(Fe) exhibits excellent adsorption abilities toward different arsenics.•MIL-88A(Fe) decorated on cotton fibers maintains outstanding adsorption activities.•The combination of MIL-88A(Fe) and cotton fibers improves its stability.•MIL-88A(Fe) decorated on cotton fibers achieves good reusability.•MIL-88A(Fe) decorated on cotton fibers exhibits potential large-scale application.
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