ABSTRACT
Downward social mobility is a well-known mental risk factor for depression, but its neural mechanism remains elusive. Here, by forcing mice to lose against their subordinates in a non-violent social contest, we lower their social ranks stably and induce depressive-like behaviors. These rank-decline-associated depressive-like behaviors can be reversed by regaining social status. In vivo fiber photometry and single-unit electrophysiological recording show that forced loss, but not natural loss, generates negative reward prediction error (RPE). Through the lateral hypothalamus, the RPE strongly activates the brain's anti-reward center, the lateral habenula (LHb). LHb activation inhibits the medial prefrontal cortex (mPFC) that controls social competitiveness and reinforces retreats in contests. These results reveal the core neural mechanisms mutually promoting social status loss and depressive behaviors. The intertwined neuronal signaling controlling mPFC and LHb activities provides a mechanistic foundation for the crosstalk between social mobility and psychological disorder, unveiling a promising target for intervention.
Subject(s)
Habenula , Social Status , Mice , Animals , Reward , Social Behavior , Habenula/physiology , DepressionABSTRACT
Melanoma cells, deriving from neuroectodermal melanocytes, may exploit the nervous system's immune privilege for growth. Here we show that nerve growth factor (NGF) has both melanoma cell intrinsic and extrinsic immunosuppressive functions. Autocrine NGF engages tropomyosin receptor kinase A (TrkA) on melanoma cells to desensitize interferon γ signaling, leading to T and natural killer cell exclusion. In effector T cells that upregulate surface TrkA expression upon T cell receptor activation, paracrine NGF dampens T cell receptor signaling and effector function. Inhibiting NGF, either through genetic modification or with the tropomyosin receptor kinase inhibitor larotrectinib, renders melanomas susceptible to immune checkpoint blockade therapy and fosters long-term immunity by activating memory T cells with low affinity. These results identify the NGF-TrkA axis as an important suppressor of anti-tumor immunity and suggest larotrectinib might be repurposed for immune sensitization. Moreover, by enlisting low-affinity T cells, anti-NGF reduces acquired resistance to immune checkpoint blockade and prevents melanoma recurrence.
Subject(s)
Melanoma , Receptor, Nerve Growth Factor , Humans , Receptor, Nerve Growth Factor/genetics , Receptor, Nerve Growth Factor/metabolism , Nerve Growth Factor/genetics , Nerve Growth Factor/metabolism , Tropomyosin , Melanoma/therapy , Receptor, trkA/genetics , Receptor, trkA/metabolism , Cytoprotection , Immune Checkpoint Inhibitors , Memory T Cells , Immunosuppression Therapy , Immunotherapy , Receptors, Antigen, T-CellABSTRACT
N6-methyladenosine (m6A) RNA modification plays important roles in the governance of gene expression and is temporally regulated in different cell states. In contrast to global m6A profiling in bulk sequencing, single-cell technologies for analyzing m6A heterogeneity are not extensively established. Here, we developed single-nucleus m6A-CUT&Tag (sn-m6A-CT) for simultaneous profiling of m6A methylomes and transcriptomes within a single nucleus using mouse embryonic stem cells (mESCs). m6A-CT is capable of enriching m6A-marked RNA molecules in situ, without isolating RNAs from cells. We adapted m6A-CT to the droplet-based single-cell omics platform and demonstrated high-throughput performance in analyzing nuclei isolated from thousands of cells from various cell types. We show that sn-m6A-CT profiling is sufficient to determine cell identity and allows the generation of cell-type-specific m6A methylome landscapes from heterogeneous populations. These indicate that sn-m6A-CT provides additional dimensions to multimodal datasets and insights into epitranscriptomic landscape in defining cell fate identity and states.
ABSTRACT
For most biological and medical applications of single-cell transcriptomics, an integrative study of multiple heterogeneous single-cell RNA sequencing (scRNA-seq) data sets is crucial. However, present approaches are unable to integrate diverse data sets from various biological conditions effectively because of the confounding effects of biological and technical differences. We introduce single-cell integration (scInt), an integration method based on accurate, robust cell-cell similarity construction and unified contrastive biological variation learning from multiple scRNA-seq data sets. scInt provides a flexible and effective approach to transfer knowledge from the already integrated reference to the query. We show that scInt outperforms 10 other cutting-edge approaches using both simulated and real data sets, particularly in the case of complex experimental designs. Application of scInt to mouse developing tracheal epithelial data shows its ability to integrate development trajectories from different developmental stages. Furthermore, scInt successfully identifies functionally distinct condition-specific cell subpopulations in single-cell heterogeneous samples from a variety of biological conditions.
Subject(s)
Single-Cell Analysis , Single-Cell Gene Expression Analysis , Animals , Mice , Single-Cell Analysis/methods , Gene Expression Profiling/methods , Exome Sequencing , Sequence Analysis, RNA/methodsABSTRACT
Non-POU domain-containing octamer-binding protein (NONO) is a multi-functional nuclear protein which belongs to the Drosophila behavior/human splicing (DBHS) protein family. NONO is known to regulate multiple important biological processes including host antiviral immune response. However, whether NONO can inhibit porcine reproductive and respiratory syndrome virus (PRRSV) replication is less well understood. In this study, we demonstrated that swine NONO (sNONO) inhibited PRRSV replication, via increasing expression of IFN-ß, whereas NONO knockdown or knockout in PAM-KNU cells was more susceptible to PRRSV infection. As an IRF3 positive regulation factor, NONO promoted IFN-ß expression by enhancing activation of IRF3. During PRRSV infection, NONO further up-regulated IRF3-mediated IFN-ß expression by interacting with PRRSV N protein. Mechanistically, NONO functioned as a scaffold protein to detect PRRSV N protein and formed N-NONO-IRF3 complex in the nucleus. Interestingly, it was found that the NONO protein reversed the inhibitory effect of PRRSV N protein on type I IFN signaling pathway. Taken together, our study provides a novel mechanism for NONO to increase the IRF3-mediated IFN-ß activation by interacting with the viral N protein to inhibit PRRSV infection.
Subject(s)
Interferon Regulatory Factor-3 , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Virus Replication , Animals , Porcine respiratory and reproductive syndrome virus/immunology , Interferon Regulatory Factor-3/metabolism , Swine , Porcine Reproductive and Respiratory Syndrome/immunology , Porcine Reproductive and Respiratory Syndrome/metabolism , Porcine Reproductive and Respiratory Syndrome/virology , Humans , Interferon-beta/metabolism , Interferon-beta/immunology , Signal Transduction , Nucleocapsid Proteins/immunology , Nucleocapsid Proteins/metabolism , HEK293 Cells , Cell Line , Immunity, InnateABSTRACT
SifiNet is a robust and accurate computational pipeline for identifying distinct gene sets, extracting and annotating cellular subpopulations, and elucidating intrinsic relationships among these subpopulations. Uniquely, SifiNet bypasses the cell clustering stage, commonly integrated into other cellular annotation pipelines, thereby circumventing potential inaccuracies in clustering that may compromise subsequent analyses. Consequently, SifiNet has demonstrated superior performance in multiple experimental datasets compared with other state-of-the-art methods. SifiNet can analyze both single-cell RNA and ATAC sequencing data, thereby rendering comprehensive multi-omic cellular profiles. It is conveniently available as an open-source R package.
Subject(s)
Single-Cell Analysis , Software , Single-Cell Analysis/methods , Humans , Molecular Sequence Annotation , Algorithms , Computational Biology/methods , Sequence Analysis, RNA/methods , Gene Expression Profiling/methods , Chromatin Immunoprecipitation Sequencing/methods , Cluster AnalysisABSTRACT
Demographic history and mutational load are of paramount importance for the adaptation of the endangered species. However, the effects of population evolutionary history and genetic load on the adaptive potential in endangered conifers remain unclear. Here, using population transcriptome sequencing, whole chloroplast genomes and mitochondrial DNA markers, combined with niche analysis, we determined the demographic history and mutational load for three threatened whitebark pines having different endangered statuses, Pinus bungeana, P. gerardiana and P. squamata. Demographic inference indicated that severe bottlenecks occurred in all three pines at different times, coinciding with periods of major climate and geological changes; in contrast, while P. bungeana experienced a recent population expansion, P. gerardiana and P. squamata maintained small population sizes after bottlenecking. Abundant homozygous-derived variants accumulated in the three pines, particularly in P. squamata, while the species with most heterozygous variants was P. gerardiana. Abundant moderately and few highly deleterious variants accumulated in the pine species that have experienced the most severe demographic bottlenecks (P. gerardiana and P. squamata), most likely because of purging effects. Finally, niche modeling showed that the distribution of P. bungeana might experience a significant expansion in the future, and the species' identified genetic clusters are also supported by differences in the ecological niche. The integration of genomic, demographic and niche data has allowed us to prove that the three threatened pines have contrasting patterns of demographic history and mutational load, which may have important implications in their adaptive potential and thus are also key for informing conservation planning.
ABSTRACT
Porcine Mx1 is a type of interferon-induced GTPase that inhibits the replication of certain RNA viruses. However, the antiviral effects and the underlying mechanism of porcine Mx1 for porcine reproductive and respiratory syndrome virus (PRRSV) remain unknown. In this study, we demonstrated that porcine Mx1 could significantly inhibit PRRSV replication in MARC-145 cells. By Mx1 segment analysis, it was indicated that the GTPase domain (68-341aa) was the functional area to inhibit PRRSV replication and that Mx1 interacted with the PRRSV-N protein through the GTPase domain (68-341aa) in the cytoplasm. Amino acid residues K295 and K299 in the G domain of Mx1 were the key sites for Mx1-N interaction while mutant proteins Mx1(K295A) and Mx1(K299A) still partially inhibited PRRSV replication. Furthermore, we found that the GTPase activity of Mx1 was dominant for Mx1 to inhibit PRRSV replication but was not essential for Mx1-N interaction. Finally, mechanistic studies demonstrated that the GTPase activity of Mx1 played a dominant role in inhibiting the N-Nsp9 interaction and that the interaction between Mx1 and N partially inhibited the N-Nsp9 interaction. We propose that the complete anti-PRRSV mechanism of porcine Mx1 contains a two-step process: Mx1 binds to the PRRSV-N protein and subsequently disrupts the N-Nsp9 interaction by a process requiring the GTPase activity of Mx1. Taken together, the results of our experiments describe for the first time a novel mechanism by which porcine Mx1 evolves to inhibit PRRSV replication. IMPORTANCE: Mx1 protein is a key mediator of the interferon-induced antiviral response against a wide range of viruses. How porcine Mx1 affects the replication of porcine reproductive and respiratory syndrome virus (PRRSV) and its biological function has not been studied. Here, we show that Mx1 protein inhibits PRRSV replication by interfering with N-Nsp9 interaction. Furthermore, the GTPase activity of porcine Mx1 plays a dominant role and the Mx1-N interaction plays an assistant role in this interference process. This study uncovers a novel mechanism evolved by porcine Mx1 to exert anti-PRRSV activities.
Subject(s)
Myxovirus Resistance Proteins , Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Viral Nonstructural Proteins , Virus Replication , Animals , Cell Line , Interferons/immunology , Interferons/metabolism , Mutation , Myxovirus Resistance Proteins/chemistry , Myxovirus Resistance Proteins/genetics , Myxovirus Resistance Proteins/metabolism , Porcine Reproductive and Respiratory Syndrome/enzymology , Porcine Reproductive and Respiratory Syndrome/metabolism , Porcine Reproductive and Respiratory Syndrome/virology , Porcine respiratory and reproductive syndrome virus/growth & development , Porcine respiratory and reproductive syndrome virus/metabolism , Protein Binding , Swine/virology , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/metabolismABSTRACT
Upon antigen engagement, augmented cytosolic reactive oxygen species (ROS) are needed to achieve optimal T cell receptor (TCR) signaling. However, uncontrolled ROS production is a prominent cause of necrosis, which elicits hyper-inflammation and tissue damage. Hence, it is critical to program activated T cells to achieve ROS equilibrium. Here, we determined that miR-23a is indispensable for effector CD4(+) T cell expansion, particularly by providing early protection from excessive necrosis. Mechanistically, miR-23a targeted PPIF, gatekeeper of the mitochondria permeability transition pore, thereby restricting ROS flux and maintaining mitochondrial integrity. Upon acute Listeria monocytogenes infection, deleting miR-23a in T cells resulted in excessive inflammation, massive liver damage, and a marked mortality increase, which highlights the essential role of miR-23a in maintaining immune homeostasis.
Subject(s)
CD4-Positive T-Lymphocytes/immunology , Listeria monocytogenes/immunology , Listeriosis/immunology , Liver/pathology , MicroRNAs/metabolism , Mitochondria/metabolism , Animals , Cells, Cultured , Peptidyl-Prolyl Isomerase F , Cyclophilins/metabolism , Homeostasis , Mice , Mice, Transgenic , MicroRNAs/genetics , Mitochondrial Membrane Transport Proteins/metabolism , Mitochondrial Permeability Transition Pore , Necrosis , RNA, Small Interfering/genetics , Reactive Oxygen Species/metabolism , Receptors, Antigen, T-Cell/metabolism , Signal Transduction/geneticsABSTRACT
Dendritic cells (DCs) orchestrate complex membrane trafficking through an interconnected transportation network linked together by Rab GTPases. Through a tandem affinity purification strategy and mass spectrometry, we depicted an interactomic landscape of major members of the mammalian Rab GTPase family. When complemented with imaging tools, this proteomic analysis provided a global view of intracellular membrane organization. Driven by this analysis, we investigated dynamic changes to the Rab32 subnetwork in DCs induced by L. monocytogenes infection and uncovered an essential role of this subnetwork in controlling the intracellular proliferation of L. monocytogenes. Mechanistically, Rab32 formed a persistent complex with two interacting proteins, PHB and PHB2, to encompass bacteria both during early phagosome formation and after L. monocytogenes escaped the original containment vacuole. Collectively, we have provided a functional compartmentalization overview and an organizational framework of intracellular Rab-mediated vesicle trafficking that can serve as a resource for future investigations.
Subject(s)
Dendritic Cells/immunology , Listeria monocytogenes/immunology , Listeriosis/immunology , Multiprotein Complexes/metabolism , rab GTP-Binding Proteins/metabolism , Acyltransferases/metabolism , Animals , Anti-Infective Agents/therapeutic use , Cell Line , Computational Biology , Containment of Biohazards , Dendritic Cells/microbiology , Listeria monocytogenes/growth & development , Listeriosis/drug therapy , Mice , Prohibitins , Protein Transport , Repressor Proteins/metabolism , Vacuoles/metabolismABSTRACT
OBJECTIVE: Catalpol (CAT) has various pharmacological activities and plays a protective role in cerebral ischemia. It has been reported that CAT played a protective role in cerebral ischemia by upregulaing NRF1 expression. Bioinformatics analysis reveals that NRF1 can be used as a transcription factor to bind to the histone acetyltransferase KAT2A. However, the role of KAT2A in cerebral ischemia remains to be studied. Therefore, we aimed to investigate the role of CAT in cerebral ischemia and its related mechanism. METHODS: In vitro, a cell model of oxygen and glucose deprivation/reperfusion (OGD/R) was constructed, followed by evaluation of neuronal injury and the expression of METTL3, Beclin-1, NRF1, and KAT2A. In vivo, a MCAO rat model was prepared by means of focal cerebral ischemia, followed by assessment of neurological deficit and brain injury in MCAO rats. Neuronal autophagy was evaluated by observation of autophagosomes in neurons or brain tissues by TEM and detection of the expression of LC3 and p62. RESULTS: In vivo, CAT reduced the neurological function deficit and infarct volume, inhibited neuronal apoptosis in the cerebral cortex, and significantly improved neuronal injury and excessive autophagy in MCAO rats. In vitro, CAT restored OGD/R-inhibited cell viability, inhibited cell apoptosis, LDH release, and neuronal autophagy. Mechanistically, CAT upregulated NRF1, NRF1 activated METTL3 via KAT2A transcription, and METTL3 inhibited Beclin-1 via m6A modification. CONCLUSION: CAT activated the NRF1/KAT2A/METTL3 axis and downregulated Beclin-1 expression, thus relieving neuronal injury and excessive autophagy after cerebral ischemia.
Subject(s)
Autophagy , Beclin-1 , Brain Ischemia , Iridoid Glucosides , Neurons , Animals , Autophagy/drug effects , Beclin-1/metabolism , Beclin-1/genetics , Rats , Neurons/metabolism , Neurons/drug effects , Brain Ischemia/metabolism , Brain Ischemia/drug therapy , Male , Iridoid Glucosides/pharmacology , Iridoid Glucosides/therapeutic use , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Disease Models, Animal , Apoptosis/drug effects , Rats, Sprague-Dawley , Reperfusion Injury/metabolism , Reperfusion Injury/drug therapy , Adenosine/analogs & derivativesABSTRACT
Understanding the structure-activity correlation is an important prerequisite for the rational design of high-efficiency electrocatalysts at the atomic level. However, the effect of coordination environment on electrocatalytic oxygen evolution reaction (OER) remains enigmatic. In this work, the regulation of proton transfer involved in water oxidation by coordination engineering based on Co3(PO4)2 and CoHPO4 is reported. The HPO4 2- anion has intermediate pKa value between Co(II)-H2O and Co(III)-H2O to be served as an appealing proton-coupled electron transfer (PCET) induction group. From theoretical calculations, the pH-dependent OER properties, deuterium kinetic isotope effects, operando electrochemical impedance spectroscopy (EIS) and Raman studies, the CoHPO4 catalyst beneficially reduces the energy barrier of proton hopping and modulates the formation energy of high-valent Co species, thereby enhancing OER activity. This work demonstrates a promising strategy that involves tuning the local coordination environment to optimize PCET steps and electrocatalytic activities for electrochemical applications. In addition, the designed system offers a motif to understand the structure-efficiency relationship from those amino-acid residue with proton buffer ability in natural photosynthesis.
ABSTRACT
The binding of T cell antigen receptors (TCRs) to specific complexes of peptide and major histocompatibility complex (pMHC) is typically of very low affinity, which necessitates the use of multimeric pMHC complexes to label T lymphocytes stably. We report here the development of pMHC complexes able to be crosslinked by ultraviolet irradiation; even as monomers, these efficiently and specifically stained cognate T cells. We also used this reagent to probe T cell activation and found that a covalently bound pMHC was more stimulatory than an agonist pMHC on lipid bilayers. This finding suggested that serial engagement of TCRs is dispensable for activation when a substantial fraction of TCRs are stably engaged. Finally, pMHC-bound TCRs were 'preferentially' transported into the central supramolecular activation cluster after activation, which suggested that ligand engagement enabled linkage of the TCR and its associated CD3 signaling molecules to the cytoskeleton.
Subject(s)
Cross-Linking Reagents/chemistry , Major Histocompatibility Complex/immunology , Receptors, Antigen, T-Cell/chemistry , T-Lymphocytes/chemistry , Animals , CD3 Complex/chemistry , CD3 Complex/immunology , Cells, Cultured , Coloring Agents/chemistry , Cytoskeleton/chemistry , Cytoskeleton/immunology , Lymphocyte Activation , Mice , Mice, Transgenic , Receptors, Antigen, T-Cell/immunology , Signal Transduction/immunology , T-Lymphocytes/immunologyABSTRACT
BACKGROUND: The coronavirus disease (COVID-19) pandemic has seriously impacted the mental and sexual health of the general population. Patients dealing with infertility constitute a unique subset within society, susceptible to heightened sensitivity amid pressures and crises. However, to the best of our knowledge, the impact of the different stages of the COVID-19 pandemic on the mental and sexual health of patients with infertility has not been investigated. Therefore, this study aimed to investigate the mental and sexual health of patients with infertility during different stages of the COVID-19 pandemic (during the lockdown, when controls were fully liberalized, and during the post-pandemic era). METHODS: This prospective before-and-after study was conducted between April and May 2022 (during the lockdown), December and January 2023 (when controls were fully liberalized), and May and August 2023 (during the post-pandemic era). This study explored the sexual and mental health of women with infertility during the three stages of the COVID-19 pandemic using standardized mental health and sexual function questionnaires. The Chi-square test was used to compare categorical data, and the ANOVA test was used to compare numerical data. RESULTS: Patients had the highest 7-item Generalized Anxiety Disorder Scale (GAD-7) and 9-item Patient Health Questionnaire (PHQ-9) scores and the highest rates of anxiety and depression during the immediate full-release phase. During the complete liberalization phase, patients had the lowest Female Sexual Function Index (FSFI) scores and the highest incidence of sexual dysfunction. CONCLUSION: This study is the first one to report the repercussions of COVID-19 on the mental and sexual well-being of individuals experiencing infertility across various phases of the pandemic. Upon the complete lifting of control measures, close to 99% of participants exhibited varying degrees of anxiety and depression. Our research underscores that individuals with infertility faced elevated levels of anxiety, depression, and sexual dysfunction during the phase of full liberalization of COVID-19 control measures, in stark contrast to the periods of lockdown and the post-pandemic era.
Subject(s)
COVID-19 , Infertility , Sexual Health , Humans , Female , Pandemics , Prospective Studies , COVID-19/epidemiology , Communicable Disease Control , Infertility/epidemiologyABSTRACT
The fast growth of electrochemical energy storage (EES) systems necessitates using innovative, high-performance electrode materials. Among the various EES devices, rechargeable batteries (RBs) with potential features like high energy density and extensive lifetime are well suited to meet rapidly increasing energy demands. Layered transition metal dichalcogenides (TMDs), typical two dimensional (2D) nanomaterial, are considered auspicious materials for RBs because of their layered structures and large specific surface areas (SSA) that benefit quick ion transportation. This review summarizes and highlights recent advances in TMDs with improved performance for various RBs. Through novel engineering and functionalization used for high-performance RBs, we briefly discuss the properties, characterizations, and electrochemistry phenomena of TMDs. We summarised that engineering with multiple techniques, like nanocomposites used for TMDs receives special attention. In conclusion, the recent issues and promising upcoming research openings for developing TMDs-based electrodes for RBs are discussed.
ABSTRACT
The NHC-catalyzed enantioselective [4 + 2] annulation of 9H-fluorene-1-carbaldenydes with cyclic imines was successfully developed. A series of optically enriched polycyclic dihydroisoquinolinones were synthesized in moderate to excellent yields with good to excellent enantioselectivities. In addition, this efficient method could also be amenable to the synthesis of spirocyclic compounds by using isatin-derived ketimines as the electrophiles.
ABSTRACT
Rapid construction of functionalized aza-anthraquinones has been successfully developed via NHC-catalyzed formal [3 + 3] annulation of 2-aminoquinones with enals. This reaction features several advantages, such as readily available starting materials, mild reaction conditions, and flexible product transformations. The study on the atroposelective version of this strategy was also carried out, and several C-N axial chiral aza-anthraquinones were synthesized in moderate yields with moderate to good enantioselectivities.
ABSTRACT
PURPOSE: To investigate the outcomes of first-line image-guided microwave ablation (MWA) plus tyrosine kinase inhibitors (TKIs) in untreated epidermal growth factor receptor (EGFR)-mutant advanced lung adenocarcinoma (LUAD), and to compare with TKIs alone. MATERIALS AND METHODS: This retrospective cohort study included patients between December 2015 and December 2021, and was divided into two groups (group A: first-line MWA+TKIs; group B: TKIs alone). Progression-free survival (PFS) was the primary endpoint, whereas overall survival (OS) was the secondary endpoint, and were compared via the Kaplan-Meier methods. Univariate and multivariate analyses were used to investigate the predictors of PFS and OS. Propensity score matching (PSM; 1:1 ratio) was applied between group B and the subgroup of complete ablation in group A. RESULTS: A total of 117 patients were included (group A: n=43; group B: n=74). In a mean follow-up of 47.0±19.4 months, group A had significantly longer median PFS (19.0 vs. 10.0 months, P<0.001) and OS (41.0 vs. 25.0 months, P=0.044) than group B. Predictors of PFS included first-line MWA (P<0.001) and tumor stage (P=0.020), while that of OS included first-line MWA (P=0.039), tumor stage (P=0.014) and usage of third-generation TKIs (P=0.001). There were 23 pairs of patients obtained after PSM (group A1: complete ablation+TKIs; group B1: TKIs alone). Group A1 had significantly longer median PFS (24.0 vs. 10.0 months, P<0.001) and OS (48.0 vs. 24.0 months, P=0.012) than group B1. CONCLUSIONS: First-line MWA significantly improved the outcomes of patients with untreated EGFR-mutant advanced LUAD treated with TKIs. Complete ablation predicts a better prognosis.
ABSTRACT
The potential application of stimuli-responsive hybrid copper halides in information storage and switch devices has generated significant interest. However, their transformation mechanism needs to be further studied deeply. Herein, two zero-dimensional (0D) organic-inorganic hybrids, namely, (TBA)CuBr2 (1) with linear [CuBr2]- units and (TBA)2Cu4Br6 (2) with [Cu4Br6]2- clusters (TBA+ = (C4H9)4N+), are synthesized using simple solvent evaporation approaches. Interestingly, upon exposure to distinct protic solvents, such as methanol, ethanol, ethylene glycol, or hot water, 1 undergoes a transformation into 2 with varying degrees of transition, accompanied by a change in luminescence color from cyan to orange (or mixed color) under high-energy emission (e.g., 254 nm) excitation. Hot water can trigger 1 to completely transform into 2 because of its large contact angle difference in the solvents. Furthermore, 2 can be converted back to 1 through a simple solid-state mechanochemical reaction. Additionally, the structure of 2 remains unchanged even after immersion in 80 °C H2O for 168 h due to the dense organic framework. This study provides valuable insights for exploring reversible structural transformation materials in the 0D metal halide system.
ABSTRACT
Calcium salt precipitation is an effective solution to wastewater fluoride pollution. The purity and precipitation efficiency of calcium fluoride is critical for its removal and recovery. This study aimed to reveal the role of coexisting sulfates in the precipitation of calcium fluoride. A low sulfate concentration promoted calcium fluoride precipitation. The size of calcium fluoride-aggregated particle clusters increased from 750 to 2000 nm when the molar ratio of sulfate to fluoride was increased from 0 to 3:100. Sulfate doped in the calcium fluoride crystals neutralized the positive charge of the calcium fluoride. Online atomic force microscopy measurements showed that sulfate reduced the repulsive force between calcium fluoride crystals and increased the adhesion force from 1.62 to 2.46 nN, promoting the agglomeration of calcium fluoride crystals. Sulfate improved the precipitation efficiency of calcium fluoride by promoting agglomeration; however, the purity of calcium fluoride was reduced by doping. Sulfate reduced the induction time of calcium fluoride crystallization and improved the nucleation rate of calcium fluoride. Sulfate should be retained to improve the precipitation of calcium fluoride and to avoid its loss from the effluents. However, it is necessary to separate sulfate from fluoride to obtain high-purity calcium fluoride. Therefore, sulfate concentration regulation in high-fluoride wastewater is key to achieving the efficient removal and recovery of fluoride ions.