Dynamic nonreversibility view of intrinsic brain organization and brain dynamic analysis of repetitive transcranial magnitude stimulation.

Intrinsic neural activities are characterized as endless spontaneous fluctuation over multiple time scales. However, how the intrinsic brain organization changes over time under local perturbation remains an open question. By means of statistical physics, we proposed an approach to capture whole-brain dynamics based on estimating time-varying nonreversibility and k-means clustering of dynamic varying nonreversibility patterns. We first used synthetic fMRI to investigate the effects of window parameters on the temporal variability of varying nonreversibility. Second, using real test-retest fMRI data, we examined the reproducibility, reliability, biological, and physiological correlation of the varying nonreversibility substates. Finally, using repetitive transcranial magnetic stimulation-fMRI data, we investigated the modulation effects of repetitive transcranial magnetic stimulation on varying nonreversibility substate dynamics. The results show that: (i) as window length increased, the varying nonreversibility variance decreased, while the sliding step almost did not alter it; (ii) the global high varying nonreversibility states and low varying nonreversibility states were reproducible across multiple datasets and different window lengths; and (iii) there were increased low varying nonreversibility states and decreased high varying nonreversibility states when the left frontal lobe was stimulated, but not the occipital lobe. Taken together, these results provide a thermodynamic equilibrium perspective of intrinsic brain organization and reorganization under local perturbation.

Low-frequency repetitive transcranial magnetic stimulation alters the individual functional dynamical landscape.

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive approach to modulate brain activity and behavior in humans. Still, how individual resting-state brain dynamics after rTMS evolves across different functional configurations is rarely studied. Here, using resting state fMRI data from healthy subjects, we aimed to examine the effects of rTMS to individual large-scale brain dynamics. Using Topological Data Analysis based Mapper approach, we construct the precise dynamic mapping (PDM) for each participant. To reveal the relationship between PDM and canonical functional representation of the resting brain, we annotated the graph using relative activation proportion of a set of large-scale resting-state networks (RSNs) and assigned the single brain volume to corresponding RSN-dominant or a hub state (not any RSN was dominant). Our results show that (i) low-frequency rTMS could induce changed temporal evolution of brain states; (ii) rTMS didn't alter the hub-periphery configurations underlined resting-state brain dynamics; and (iii) the rTMS effects on brain dynamics differ across the left frontal and occipital lobe. In conclusion, low-frequency rTMS significantly alters the individual temporo-spatial dynamics, and our finding further suggested a potential target-dependent alteration of brain dynamics. This work provides a new perspective to comprehend the heterogeneous effect of rTMS.

Quantifying the energy landscape in weakly and strongly disordered frictional media.

We investigate the "roughness" of the energy landscape of a system that diffuses in a heterogeneous medium with a random position-dependent friction coefficient α(x). This random friction acting on the system stems from spatial inhomogeneity in the surrounding medium and is modeled using the generalized Caldira-Leggett model. For a weakly disordered medium exhibiting a Gaussian random diffusivity D(x) = kBT/α(x) characterized by its average value ⟨D(x)⟩ and a pair-correlation function ⟨D(x1)D(x2)⟩, we find that the renormalized intrinsic diffusion coefficient is lower than the average one due to the fluctuations in diffusivity. The induced weak internal friction leads to increased roughness in the energy landscape. When applying this idea to diffusive motion in liquid water, the dissociation energy for a hydrogen bond gradually approaches experimental findings as fluctuation parameters increase. Conversely, for a strongly disordered medium (i.e., ultrafast-folding proteins), the energy landscape ranges from a few to a few kcal/mol, depending on the strength of the disorder. By fitting protein folding dynamics to the escape process from a metastable potential, the decreased escape rate conceptualizes the role of strong internal friction. Studying the energy landscape in complex systems is helpful because it has implications for the dynamics of biological, soft, and active matter systems.

Atypical anti-glomerular basement membrane disease with membranous hyperplasia: diagnostic challenges and treatment variability.

This case report presents a detailed analysis of a 31-year-old male patient who presented with a complex array of clinical symptoms, including proteinuria, hematuria, edema, and kidney insufficiency. Despite undergoing multiple tests, the results for anti-glomerular basement membrane antibodies yielded negative findings. Subsequently, kidney biopsy pathology revealed a distinct diagnosis of atypical anti-glomerular basement membrane (anti-GBM) disease with membrane hyperplasia. Treatment was initiated with a comprehensive approach involving high doses of corticosteroids therapy and cyclophosphamide (CTX). However, contrary to expectations, the patient's kidney function exhibited rapid deterioration following this therapeutic regimen. The culmination of these complications necessitated a pivotal transition to maintenance hemodialysis. This case underscores the intricate challenges associated with diagnosing and managing rare and atypical presentations of kidney disorders. The negative anti-GBM antibody results and subsequent identification of atypical anti-GBM nephropathy highlight the need for tailored diagnostic strategies to discern subtle nuances within complex clinical scenarios. Additionally, the unexpected response to the treatment regimen emphasizes the potential variability in individual patient responses, underlining the necessity for vigilant monitoring and adaptable treatment strategies. This case report contributes to the evolving understanding of atypical kidney pathologies and the complexities involved in their management.

Polydatin alleviates bleomycin-induced pulmonary fibrosis and alters the gut microbiota in a mouse model.

To investigate the effect and mechanism of polydatin on bleomycin (BLM)-induced pulmonary fibrosis in a mouse model. The lung fibrosis model was induced by BLM. The contents of TNF-α, LPS, IL-6 and IL-1ß in lung tissue, intestine and serum were detected by ELISA. Gut microbiota diversity was detected by 16S rDNA sequencing; R language was used to analyse species composition, α-diversity, ß-diversity, species differences and marker species. Mice were fed drinking water mixed with four antibiotics (ampicillin, neomycin, metronidazole, vancomycin; antibiotics, ABx) to build a mouse model of ABx-induced bacterial depletion; and faecal microbiota from different groups were transplanted into BLM-treated or untreated ABx mice. The histopathological changes and collagen I and α-SMA expression were determined. Polydatin effectively reduced the degree of fibrosis in a BLM-induced pulmonary fibrosis mouse model; BLM and/or polydatin affected the abundance of the dominant gut microbiota in mice. Moreover, faecal microbiota transplantation (FMT) from polydatin-treated BLM mice effectively alleviated lung fibrosis in BLM-treated ABx mice compared with FMT from BLM mice. Polydatin can reduce fibrosis and inflammation in a BLM-induced mouse pulmonary fibrosis model. The alteration of gut microbiota by polydatin may be involved in the therapeutic effect.

Highly Robust {In2}-Organic Framework for Efficiently Catalyzing CO2 Cycloaddition and Knoevenagel Condensation.

To improve the catalytic performance of metal-organic frameworks (MOFs), creating higher defects is now considered as the most effective strategy, which can not only optimize the Lewis acidity of metal ions but also create more pore space to enhance diffusion and mass transfer in the channels. Herein, the exquisite combination of scarcely reported [In2(CO2)5(H2O)2(DMF)2] clusters and 2,6-bis(2,4-dicarboxylphenyl)-4-(4-carboxylphenyl)pyridine (H5BDCP) under solvothermal conditions generated a highly robust nanoporous framework of {[In2(BDCP)(DMF)2(H2O)2](NO3)}n (NUC-65) with nanocaged voids (14.1 Å) and rectangular nanochannels (15.94 Å × 11.77 Å) along the a axis. It is worth mentioning that an In(1) ion displays extremely low tetra-coordination modes after the thermal removal of its associated four solvent molecules of H2O and DMF. Activated {[In2(BDCP)](Br)}n (NUC-65Br), as a defective material because of its extremely unsaturated metal centers, could be generated by bromine ion exchange, solvent exchange, and vacuum drying. Catalytic experiments proved that the conversion of epichlorohydrin with 1 atm CO2 into 4-(chloromethyl)-1,3-dioxolan-2-one catalyzed by 0.11 mol % NUC-65Br could reach 99% at 65 °C within 24 h. Moreover, with the aid of 5 mol % cocatalyst n-Bu4NBr, heterogeneous NUC-65Br owns excellent universal catalytic performance in most epoxides under mild conditions. In addition, NUC-65Br, as a heterogeneous catalyst, exhibits higher activity and better selectivity for Knoevenagel condensation of aldehydes and malononitrile. Hence, this work offers a fresh insight into the design of structure defect cationic metal-organic frameworks, which can be better applied to various fields because of their promoted performance.

Eu(III)-Functionalized MOF-Based Dual-Emission Ratiometric Sensor Integrated with Logic Gate Operation for Efficient Detection of Hippuric Acid in Urine and Serum.

With the introduction of Eu3+ ions as the secondary fluorescent signal reporter and sensing active sites, a dual-emission ratiometric sensor of Eu3+@NiMOF (Eu3+ functional NiMOF) for hippuric acid (HA) detection in urine and serum was fabricated via the postsynthetic encapsulating strategy. Based on the two emission signals at 441 nm (turn-on) and 628 nm (turn-off), the produced Eu3+@NiMOF ratiometric sensor provided enhanced sensitivity, higher selectivity, and 9.7 times lower limits of detection (LOD) for the detection of HA (2.38 µM, 0.42 µg·mL-1) than that of the pristine NiMOF. Considering the high sensitivity and visualization results, further exploration of intelligent applications in the HA sensing process was carried out by constructing a tandem combinational logic gate to improve the practicability and convenience with the help of a smartphone. This work provides a promising approach for developing MOF-based ratiometric sensors to detect biomarkers.

A TNF-α blocking peptide that reduces NF-κB and MAPK activity for attenuating inflammation.

Overexpression of tumor necrosis factor-α (TNF-α) is implicated in many inflammatory diseases, including septic shock, hepatitis, asthma, insulin resistance and autoimmune diseases, such as rheumatoid arthritis and Crohn's disease. The TNF-α signaling pathway is a valuable target, and anti-TNF-α drugs are successfully used to treat autoimmune and inflammatory diseases. Here, we study anti-inflammatory activity of an anti-TNF-α peptide (SN1-13, DEFHLELHLYQSW). In the cellular level assessment, SN1-13 inhibited TNF-α-induced cytotoxicity and blocks TNF-α-triggered signaling activities (IC50 = 15.40 µM). Moreover, the potential binding model between SN1-13 and TNF-α/TNFRs conducted through molecular docking revealed that SN1-13 could stunt TNF-α mediated signaling thought blocking TNF-α and its receptor TNFR1 and TNFR2. These results suggest that SN1-13 would be a potential lead peptide to treat TNF-α-mediated inflammatory diseases.

Low expression of LncRNA AFAP1-AS1 inhibits proliferation and promotes apoptosis of non-small cell lung cancer cells through inhibiting wnt signaling pathway.

To detect the effects of long non-coding ribonucleic acid (lncRNA) actin filament-associated protein 1-antisense RNA1 (AFAP1-AS1) on the proliferation and apoptosis of non-small cell lung cancer (NSCLC) A549 cells and its mechanism. 1) The expression of lncRNA AFAP1-AS1 in NSCLC A549 cells was detected via quantitative reverse transcription-polymerase chain reaction (qRT-PCR). 2) The changes in proliferation and apoptosis of A549 cells after low expression of lncRNA AFAP1-AS1 were detected using cell counting kit-8 (CCK-8) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays. 3) The changes in Wnt signaling pathway proteins in A549 cells after low expression of lncRNA AFAP1-AS1 were detected using Western blotting. 1) The expression of lncRNA AFAP1-AS1 rose in A549 cells (P<0.01). 2) After low expression of lncRNA AFAP1-AS1, the growth of A549 cells was inhibited, and apoptosis was promoted. 3) After low expression of lncRNA AFAP1-AS1, the mRNA and protein expressions of glycogen synthase kinase (GSK) and ß-catenin declined (P<0.05). Lowly-expressed AFAP1-AS1 inhibits the proliferation and promotes the apoptosis of NSCLC A549 cells via inhibiting the Wnt signaling pathway.

Chemical composition and therapeutic mechanism of Xuanbai Chengqi Decoction in the treatment of COVID-19 by network pharmacology, molecular docking and molecular dynamic analysis.

Xuanbai Chengqi Decoction (XBCQD), a classic traditional Chinese medicine, has been widely used to treat COVID-19 in China with remarkable curative effect. However, the chemical composition and potential therapeutic mechanism is still unknown. Here, we used multiple open-source databases and literature mining to select compounds and potential targets for XBCQD. The COVID-19 related targets were collected from GeneCards and NCBI gene databases. After identifying putative targets of XBCQD for the treatment of COVID-19, PPI network was constructed by STRING database. The hub targets were extracted by Cytoscape 3.7.2 and MCODE analysis was carried out to extract modules in the PPI network. R 3.6.3 was used for GO enrichment and KEGG pathway analysis. The effective compounds were obtained via network pharmacology and bioinformatics analysis. Drug-likeness analysis and ADMET assessments were performed to select core compounds. Moreover, interactions between core compounds and hub targets were investigated through molecular docking, molecular dynamic (MD) simulations and MM-PBSA calculations. As a result, we collected 638 targets from 61 compounds of XBCQD and 845 COVID-19 related targets, of which 79 were putative targets. Based on the bioinformatics analysis, 10 core compounds and 34 hub targets of XBCQD for the treatment of COVID-19 were successfully screened. The enrichment analysis of GO and KEGG indicated that XBCQD mainly exerted therapeutic effects on COVID-19 by regulating signal pathways related to viral infection and inflammatory response. Meanwhile, the results of molecular docking showed that there was a stable binding between the core compounds and hub targets. Moreover, MD simulations and MM-PBSA analyses revealed that these compounds exhibited stable conformations and interacted well with hub targets during the simulations. In conclusion, our research comprehensively explained the multi-component, multi-target, and multi-pathway intervention mechanism of XBCQD in the treatment of COVID-19, which provided evidence and new insights for further research.

Emodin inhibiting epithelial-mesenchymal transition in pulmonary fibrosis through the c-MYC/miR-182-5p/ZEB2 axis.

Emodin is a natural anthraquinone compound, which is the main component found in the traditional Chinese herb Polygonum cuspidatum. The anti-fibrosis effects of Emodin have been reported. This study aimed to explore the specific mechanism of Emodin in the epithelial-mesenchymal transition (EMT) of pulmonary fibrosis. The pulmonary fibrosis mice models were constructed with bleomycin, the EMT models of alveolar epithelial cells were stimulated by TGF-ß1, and Emodin was used for intervention. c-MYC and miR-182-5p were overexpressed or silenced by cell transfection. Our results demonstrated that Emodin attenuated pulmonary fibrosis induced by bleomycin in mice, and inhibited EMT, meanwhile downregulated c-MYC, upregulated miR-182-5p, and downregulated ZEB2 in vitro and vivo. Next, overexpression of c-MYC promoted EMT, while silencing c-MYC and overexpressing miR-182-5p inhibited EMT. Then, c-MYC negatively regulated the expression of miR-182-5p with a direct binding relationship. And miR-182-5p inhibited ZEB2 expression in a targeted manner. Finally, Emodin inhibited EMT that had been promoted by overexpression of c-MYC. In conclusion, Emodin could attenuate pulmonary fibrosis and EMT by regulating the c-MYC/miR-182-5p/ZEB2 axis, which might provide evidence for the application of Emodin in the treatment of pulmonary fibrosis.

Identification and Characterization of a Novel Cathelicidin from Hydrophis cyanocinctus with Antimicrobial and Anti-Inflammatory Activity.

The abuse of antibiotics and lack of new antibacterial drugs has led to the emergence of superbugs that raise fears of untreatable infections. The Cathelicidin family of antimicrobial peptide (AMP) with varying antibacterial activities and safety is considered to be a promising alternative to conventional antibiotics. In this study, we investigated a novel Cathelicidin peptide named Hydrostatin-AMP2 from the sea snake Hydrophis cyanocinctus. The peptide was identified based on gene functional annotation of the H. cyanocinctus genome and bioinformatic prediction. Hydrostatin-AMP2 showed excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria, including standard and clinical Ampicillin-resistant strains. The results of the bacterial killing kinetic assay demonstrated that Hydrostatin-AMP2 had faster antimicrobial action than Ampicillin. Meanwhile, Hydrostatin-AMP2 exhibited significant anti-biofilm activity including inhibition and eradication. It also showed a low propensity to induce resistance as well as low cytotoxicity and hemolytic activity. Notably, Hydrostatin-AMP2 apparently decreased the production of pro-inflammatory cytokines in the LPS-induced RAW264.7 cell model. To sum up, these findings indicate that Hydrostatin-AMP2 is a potential peptide candidate for the development of new-generation antimicrobial drugs fighting against antibiotic-resistant bacterial infections.

Heterometallic ZnHoMOF as a Dual-Responsive Luminescence Sensor for Efficient Detection of Hippuric Acid Biomarker and Nitrofuran Antibiotics.

Developing efficient and sensitive MOF-based luminescence sensors for bioactive molecule detection is of great significance and remains a challenge. Benefiting from favorable chemical and thermal stability, as well as excellent luminescence performance, a porous Zn(II)Ho(III) heterometallic-organic framework (ZnHoMOF) was selected here as a bifunctional luminescence sensor for the early diagnosis of a toluene exposure biomarker of hippuric acid (HA) through "turn-on" luminescence enhancing response and the daily monitoring of NFT/NFZ antibiotics through "turn-off" quenching effects in aqueous media with high sensitivity, acceptable selectivity, good anti-interference, exceptional recyclability performance, and low detection limits (LODs) of 0.7 ppm for HA, 0.04 ppm for NFT, and 0.05 ppm for NFZ. Moreover, the developed sensor was employed to quantify HA in diluted urine samples and NFT/NFZ in natural river water with satisfactory results. In addition, the sensing mechanisms of ZnHoMOF as a dual-response chemosensor in efficient detection of HA and NFT/NFZ antibiotics were conducted from the view of photo-induced electron transfer (PET), as well as inner filter effects (IFEs), with the help of time-dependent density functional theory (TD-DFT) and spectral overlap experiments.

Nanocage-Based Tb3+-Organic Framework for Efficiently Catalyzing the Cycloaddition Reaction of CO2 with Epoxides and Knoevenagel Condensation.

The catalytic performance of metal-organic framework (MOF)-based catalysts can be enhanced by increasing their catalytic sites, which prompts us to explore the multicore cluster-based skeletons by using designed functional ligands. Herein, the exquisite combination of [Tb4(µ2-OH)2(CO2)8] cluster and 2,6-bis(2,4-dicarboxylphenyl)-4-(4-carboxylphenyl)pyridine (H5BDCP) ligand generated a highly robust nanoporous framework of {[Tb4(BDCP)2(µ2-OH)2]·3DMF·5H2O}n (NUC-58), in which each four {Tb4} clusters are woven together to generate an elliptical nanocage (aperature ca. 12.4 Å). As far as we know, NUC-58 is an excellent nanocage-cluster-based {Tb4}-organic framework with the outstanding confined pore environments of a large specific surface area, high porosity, and plentiful coexisting Lewis acid-base sites of Tb3+, µ2-OH and Npyridine atoms. Performed experiments exhibited that NUC-58 owns a better catalytic performance for the cycloaddition reactions under mild conditions with a high turnover number and turnover frequency. Furthermore, NUC-58, as an eminent heterogeneous catalyst, can enormously boost the Knoevenagel condensation reactions. Thus, this work opens a path for the precise design of polynuclear metal cluster-based MOFs with excellent catalysis, stability, and regenerative behavior.

Fluorine-Functionalized NbO-Type {Cu2}-Organic Framework: Enhanced Catalytic Performance on the Cycloaddition Reaction of CO2 with Epoxides and Deacetalization-Knoevenagel Condensation.

The high catalytic activity of metal-organic frameworks (MOFs) can be realized by increasing their effective active sites, which prompts us to perform the functionalization on selected linkers by introducing a strong Lewis basic group of fluorine. Herein, the exquisite combination of paddle-wheel [Cu2(CO2)4(H2O)] clusters and meticulously designed fluorine-funtionalized tetratopic 2',3'-difluoro-[p-terphenyl]-3,3″,5,5″-tetracarboxylic acid (F-H4ptta) engenders one peculiar nanocaged {Cu2}-organic framework of {[Cu2(F-ptta)(H2O)2]·5DMF·2H2O}n (NUC-54), which features two types of nanocaged voids (9.8 Å × 17.2 Å and 10.1 Å × 12.4 Å) shaped by 12 paddle-wheel [Cu2(COO)4H2O)2] secondary building units, leaving a calculated solvent-accessible void volume of 60.6%. Because of the introduction of plentifully Lewis base sites of fluorine groups, activated NUC-54a exhibits excellent catalytic performance on the cycloaddition reaction of CO2 with various epoxides under mild conditions. Moreover, to expand the catalytic scope, the deacetalization-Knoevenagel condensation reactions of benzaldehyde dimethyl acetal and malononitrile were performed using the heterogenous catalyst of NUC-54a. Also, NUC-54a features high recyclability and catalytic stability with excellent catalytic performance in subsequent catalytic tests. Therefore, this work not only puts forward a new solution for developing high-efficiency heterogeneous catalysts, but also enriches the functionalization strategies for nanoporous MOFs.

Polydatin alleviates DSS- and TNBS-induced colitis by suppressing Th17 cell differentiation via directly inhibiting STAT3.

Inflammatory bowel disease (IBD) is a non-specific chronic intestinal inflammatory disease, often presenting with abdominal pain, diarrhea, bloody stool, anorexia, and body loss. It is difficult to cure completely and a promising treatment is urgently needed. Natural compounds can offer promising chemical agents for treatment of diseases. Polydatin is a natural ingredient extracted from the dried rhizome of Polygonum cuspidatum, which has anti-inflammatory, anti-tumor, and dementia protection activities. The purpose of this study was to evaluate the therapeutic effect of polydatin on IBD and explore its possible mechanism. We found that polydatin could effectively suppress the differentiation of Th17 cells in vitro, but had no effect on the differentiation of Treg cells. Polydatin significantly alleviated colitis induced by dextran sulfate sodium (DSS) and 2, 4, 6-trinitrobenzenesulfonic acid (TNBS) in mice, and dramatically decreased the proportion of Th17 cells in spleen and mesenteric lymph nodes. Mechanism investigations revealed that polydatin specifically inhibited signal transducer and activator of transcription 3 (STAT3) phosphorylation by directly binding to STAT3, leading to Th17 cell reduction and thereby alleviating colitis. These findings provide novel insights into the anti-colitis effect of polydatin, which may be a promising drug candidate for the treatment of IBD.

m6A regulator-mediated RNA methylation modification patterns and immune microenvironment infiltration characterization in severe asthma.

N6-methyladenosine (m6A) modification is one of the most prevalent RNA modification forms of eukaryotic mRNA and is an important post-transcriptional mechanism for regulating genes. However, the role of m6A modification in the regulation of severe asthma has never been reported. Thus, we aimed to investigate the m6A regulator-mediated RNA methylation modification patterns and immune microenvironment infiltration characterization in severe asthma. In this study, 87 healthy controls and 344 severe asthma cases from the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes) programme were used to systematically evaluate the m6A modification patterns mediated by 27 m6A regulators and to investigate the effects of m6A modification on immune microenvironment characteristics. We found that 16 m6A regulators were abnormal and identified two key m6A regulators (YTHDF3 and YTHDC1) and three m6A modification patterns. The study of infiltration characteristics of immune microenvironment found that pattern 2 had more infiltrating immune cells and more active immune response. Besides, it was found that the eosinophils which are very important for severe asthma were affected by YTHDF3 and EIF3B. We also verified key m6A regulators with merip-seq and found that they were mainly distributed in exons and enriched in 3'UTR. In conclusion, our findings suggested that m6A modification plays a key role in severe asthma, and may be able to guide the future strategy of immunotherapy.

One Robust Microporous TmIII-Organic Framework for Highly Catalytic Activity on Chemical CO2 Fixation and Knoevenagel Condensation.

In terms of documented references, multifunctional MOFs with high catalytic performance could be constructed from the combination of metal cations and polycarboxyl-pyridine ligands, which could efficiently endow crystallized porous frameworks with the coexisting Lewis acid-base properties. Thus, by employing a ligand-directed synthetic strategy, the exquisite combination of wave-like inorganic chains of [Tm(CO2)3(OH2)]n and mononuclear units of [Tm(CO2)4(OH2)2] with the aid of the specially designed ligand of 2,6-bis(2,4-dicarboxylphenyl)-4-(4-carboxylphenyl)pyridine (H5BDCP) generates one highly robust microporous framework of {(Me2NH2)[Tm3(BDCP)2)(H2O)3]·4DMF·H2O}n (simplified as NUC-25), which contains near-rectangular nanochannels and large solvent-residing voids. Furthermore, the activated state of NUC-25 with the removal of associated water molecules is a rarely reported bifunctional heterogeneous catalyst due to the coexistence of Lewis acid-base sites including 6-coordinated Tm3+ ions, uncoordinated carboxyl oxygen atoms, and Npyridine atoms. Just as expected, NUC-25 exhibits greatly high catalytic activity for the cycloaddition reaction of epoxides with CO2 into alkyl cyclic carbonates under bland solvent-free conditions, which should be ascribed to the polarity of nitrogen-containing pyridine heterocycles as Lewis base sites on the inner surface of nano-caged voids except for recognized Lewis acid sites of rare earth cations. Moreover, the excellent pore-size-dependent catalytic property for Knoevenagel condensation reactions confirms that NUC-25 can be viewed as a recyclable bifunctional heterogeneous catalyst. Therefore, these results strongly demonstrate that microporous MOFs assembled from pre-designed polycarboxyl-heterocyclic ligands display better catalytic performance not only for chemical CO2 fixation but also for Knoevenagel condensation reactions.

V═O Functionalized {Tm2}-Organic Framework Designed by Postsynthesis Modification for Catalytic Chemical Fixation of CO2 and Oxidation of Mustard Gas.

In terms of recently documented references, the introduction of V═O units into porous MOF/COF frameworks can greatly improve their original performance and expand their application prospects due to a change in their electronegativity. In this work, by a cation-exchange strategy, a consummate combination of separate 4f [Tm2(CO2)8] SBUs and 3d [VIVO(H2O)2] units generated the functionalized porous metal-organic framework {(Me2NH2)2[VO(H2O)][Tm2(BDCP)2]·3DMF·3H2O}n (NUC-11), in which [Tm2(CO2)8] SBUs constitute the fundamental 3D host framework of {[Tm2](BDCP)2}n along with [VIVO(H2O)2] units being further docked on the inner wall of channels by covalent bonds. Significantly, NUC-11 represents the first example of V═O modified porous MOFs, in which uncoordinated carboxylic groups (-CO2H) further grasp the functional [VIVO(H2O)2] units on the initial basic skeleton along with the formation of covalent bonds as fixed ropes. Furthermore, activated samples of NUC-11 displayed a good catalytic performance for the chemical synthesis of carbonates from related epoxides and CO2 with high conversion rate. Moreover, by employing NUC-11 as a catalyst, a simulator of mustard gas, 2-chloroethyl ethyl sulfide, could be quickly and efficiently oxidized into low-toxicity products of oxidized sulfoxide (CEESO). Thus, this study offers a brand new view for the design and synthesis of functional-units-modified porous MOFs, which could be potentially applied as an excellent candidate in the growing field of efficient catalysis.

6s-3d {Ba3Zn4}-Organic Framework as an Effective Heterogeneous Catalyst for Chemical Fixation of CO2 and Knoevenagel Condensation Reaction.

The exquisite combination of Ba2+ and Zn2+ with the aid of 2,4,6-tri(2,4-dicarboxyphenyl)pyridine (H6TDP) under the condition of solvothermal self-assembly generates one highly robust [Ba3Zn4(CO2)12(HCO2)2(OH2)2]-organic framework of {[Ba3Zn4(TDP)2(HCO2)2(OH2)2]·7DMF·4H2O}n (NUC-27), in which adjacent 2D layers are interlaced via hydrogen-bonding interactions to form a 3D skeleton with peapod-like channels and nano-caged voids. It is worth emphasizing that both Ba2+ and Zn2+ ions in NUC-27 display the extremely low coordination modes: hexa-coordinated [Ba(1)] and tetra-coordinated [Ba(2), Zn(1), and Zn(2)]. Furthermore, to the best our knowledge, NUC-27 is one scarcely reported 2D-based nanomaterial with an unprecedented Z-shaped hepta-nuclear heterometallic cluster of [Ba3Zn4(CO2)12(HCO2)2(OH2)2] as SBUs, which not only has plentiful low-coordinated open metal sites but also has the excellent physicochemical properties including omni-directional opening pores, ultrahigh porosity, larger specific surface area, and the coexistence of Lewis acid-base sites. Just as expected, thanks to its rich active metal sites and pyridine groups as strong Lewis acid-base roles, completely activated NUC-27 displays high catalytic efficiency on the chemical transformation of epoxides with CO2 into cyclic carbonates under mild conditions and effectively accelerates the reaction process of Knoevenagel condensation.