Modulation of microglial polarization by sequential targeting surface-engineered exosomes improves therapy for ischemic stroke.

Microglia are important cells that act on regulating neuroinflammation and neurofunction after the induction of ischemic stroke (IS). Consequently, the efficient accumulation of drugs within ischemic regions, particularly in microglia, serves as a valuable approach for achieving effective therapy by attenuating microglia-mediated cerebral ischemic injury. In this study, we designed mannose (man)-conjugated luteolin (lut)-loaded platelet-derived exosomes (lut/man-pEXO) as surface engineered multifunctional cascade-delivery drug carriers to target ischemic blood vessels and subsequent microglia to enhance drug accumulation and induce neuroprotection of neurovascular unit (NVU) against IS. The results revealed that as platelets naturally gathered in pathological ischemic cerebral vessels, lut/man-pEXO could bind to platelets and efficiently target ischemic injury sites. Moreover, owing to the selective binding affinity of mannose present in lut/man-pEXO towards the mannose receptor expressed on microglia, lut/man-pEXO exhibited superior microglia-targeting properties, inducing the increased uptake of lut by microglia. As a result, lut/man-pEXO regulated microglia by inhibiting the activation of detrimental M1 and promoting the transition towards the anti-inflammatory type (M2), thus attenuating ischemic damage of NVU by reducing the infarct area, rescuing the damage of blood-brain barrier (BBB) and preventing inflammatory transformation of astrocytes.

Effect of combined physical and cognitive intervention on fear of falling in older adults: A systematic review and meta-analysis.

OBJECTIVE: Fear of falling (FOF) is common among older adults. Currently, physical exercise, cognitive intervention, and combined physical and cognitive intervention have been proven to be effective interventions. However, whether combined interventions can provide additional benefits than single interventions remains unclear. Thus, the systematic and meta-analysis was conducted to explore the immediate and retention effects of combined physical and cognitive interventions, in comparison with a single intervention. MATERIALS AND METHODS: Randomized controlled trials of combined interventions on FOF in older adults were searched using Web of Science, PubMed, Cochrane Library, EMBASE, SCOPUS, CINAHL, and PsycINFO from inception to March 20, 2023. The risk of bias in included studies was evaluated using the Cochrane Collaboration Risk of Bias tool. Two independent researchers extracted the data using predetermined criteria. RESULTS: 31 studies were included in the systematic review and meta-analysis. For the immediate post-intervention effect, the combined intervention was more effective than the blank/placebo/conventional intervention and the single cognitive intervention, while no additional effect was observed compared with the single physical intervention. Moreover, no additional follow-up retention effects were found when comparing the combined intervention with the single intervention. CONCLUSIONS: Combined interventions had positive immediate effects on FOF in older adults, compared with single cognitive intervention, while combined interventions had a similar effect as a single physical intervention. More well-designed studies are required to explore the additional benefits of combined interventions compared with a single intervention and to investigate the follow-up effects of combined interventions.

Human TRMT1 catalyzes m2G or m22G formation on tRNAs in a substrate-dependent manner.

TRMT1 is an N2-methylguanosine (m2G) and N2,N2-methylguanosine (m22G) methyltransferase that targets G26 of both cytoplasmic and mitochondrial tRNAs. In higher eukaryotes, most cytoplasmic tRNAs with G26 carry m22G26, although the majority of mitochondrial G26-containing tRNAs carry m2G26 or G26, suggesting differences in the mechanisms by which TRMT1 catalyzes modification of these tRNAs. Loss-of-function mutations of human TRMT1 result in neurological disorders and completely abrogate tRNA:m22G26 formation. However, the mechanism underlying the independent catalytic activity of human TRMT1 and identity of its specific substrate remain elusive, hindering a comprehensive understanding of the pathogenesis of neurological disorders caused by TRMT1 mutations. Here, we showed that human TRMT1 independently catalyzes formation of the tRNA:m2G26 or m22G26 modification in a substrate-dependent manner, which explains the distinct distribution of m2G26 and m22G26 on cytoplasmic and mitochondrial tRNAs. For human TRMT1-mediated tRNA:m22G26 formation, the semi-conserved C11:G24 serves as the determinant, and the U10:A25 or G10:C25 base pair is also required, while the size of the variable loop has no effect. We defined the requirements of this recognition mechanism as the "m22G26 criteria". We found that the m22G26 modification occurred in almost all the higher eukaryotic tRNAs conforming to these criteria, suggesting the "m22G26 criteria" are applicable to other higher eukaryotic tRNAs.

[Functionalized exosome-loaded ginsenoside Rg1 for the treatment of ischemic stroke].

The aim of this study was to investigate the therapeutic effects and potential mechanism of c(RGDyK) peptide modified mesenchymal stem cell exosomes loaded with ginsenoside Rg1 (G-Rg1) on ischemic stroke. Thread-tying method was used to establish SD rats transient middle cerebral occlusion model (tMCAO). The model rats were randomly divided into tMCAO group, Exo group, free G-Rg1 group, Exo-Rg1 group and cRGD-Exo-Rg1 group, and sham group was used as control. The infarct volume was measured by 2, 3, 5-triphenyltetrachloride (TTC) staining, the changes of neuron and endothelium were observed by immunofluorescence, and the expression of related proteins was detected by Western blotting. The results showed that cRGD-Exo-Rg1 up-regulated the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factors (HIF-1α) by activating PI3K/AKT pathway, thus promoting angiogenesis and neurogenesis, effectively reducing the volume of cerebral infarction and improving neural function. In addition, the delivery of cRGD-Exo-Rg1 to ischemic brain tissue up-regulated the expression of occludin and claudin-5, and reduced the injury of blood-brain barrier. Taken together, cRGD-Exo-Rg1 was effective in the treatment of ischemic stroke by promoting angiogenesis and neurogenesis, which provided experimental evidence for the potential clinical benefits of other neuroprotective therapies.

Nontargeted detection and recognition of adulterants in milk powder using Raman imaging and neural networks.

Raman imaging technology combined with targeted chemometrics can play a vital role in the rapid detection of milk powder adulteration, which threatens the lives of infants and other people. However, these methods always suffer from a narrow detection range. Nontargeted methods show a broader detection range but cannot recognize adulterants. Here, a novel nontargeted chemometric method, named as the adversarial discrimination neural network (ADNN), is proposed to detect and recognize adulterants simultaneously. The method comprises building a tight boundary in the feature space of Raman images to discriminate milk powder samples from the majority of adulterated cases. Then a first-order partial derivative of the ADNN is calculated to recognize different adulterants through a local approximation strategy. A validation set containing samples adulterated with various adulterants at concentrations ranging from 0.3% to 1.5% w/w was provided to challenge the proposed method. The validated detection accuracy of the proposed method for authentic and adulterated samples was 99.9% and 99.7% and the adulterants were recognized correctly. The ADNN-Raman represents a novel nontargeted and end-to-end tool for detecting and recognizing adulterants in milk powder simultaneously, providing new insights into nontargeted chemometric analysis.

A miniature CuO nanoarray sensor for noninvasive detection of trace salivary glucose.

An ultrasensitive mini-sensor has been developed for nonenzymatic and noninvasive determination of trace glucose in saliva. The miniature detector exhibits ultra-high sensitivity and resolution at very low glucose concentration owing to the excellent electrocatalytic activity and electron transfer rate of the prepared 3D ordered CuO nanoflake array in-situ grown on a copper foil. The structure and morphology of the cupric oxide nanoarray were characterized by X-ray powder diffraction and scanning electron microscopy. The electrocatalysis of the CuO nanoarray modified electrode to glucose was demonstrated by cyclic voltammetry and chronoamperometry. The modified electrode presents a high sensitivity of 4954 µA mM-1 cm-2 to glucose at + 0.55 V with a wide linear range of 1.0 µmol/L to 6000 µmol/L and a low detection limit of 0.1 µmol/L and long-term stability. Furthermore, the mini-sensor can clearly distinguish diabetics from healthy people because of its excellent sensing performance. The developed miniaturized sensor holds the prospect for noninvasive determination of trace glucose in saliva for diabetic patients.

Recognizing the Importance of Fast Nonisothermal Crystallization for High-Performance Two-Dimensional Dion-Jacobson Perovskite Solar Cells with High Fill Factors: A Comprehensive Mechanistic Study.

Two-dimensional (2D) Dion-Jacobson (DJ) perovskite solar cells (PSCs), despite their advantage in versatility of n-layer variation, are subject to poor photovoltaic efficiency, particularly in the fill factor (FF), compared to their three-dimensional counterparts. To enhance the performance of DJ PSCs, the process of growing crystals and hence the corresponding morphology of DJ perovskites are of prime importance. Herein, we report the fast nonisothermal (NIT) crystallization protocol that is previously unrecognized for 2D perovskites to significantly improve the morphology, orientation, and charge transport of the DJ perovskite films. Comprehensive mechanistic studies reveal that the NIT effect leads to the secondary crystallization stage, forming network-like channels that play a vital role in the FF's leap-forward improvement and hence the DJ PSC's performance. As a whole, the NIT crystallized PSCs demonstrate a high power conversion efficiency and an FF of up to 19.87 and 86.16%, respectively. This research thus provides new perspectives to achieve highly efficient DJ PSCs.

Multicomponent Composite Membrane with Three-Phase Interface Heterostructure as Photocatalyst for Organic Dye Removal.

A multicomponent composite membrane (P-S-T/C) with three-phase interface heterostructure is ingeniously designed. A polydopamine (PDA)-modified conductive carbon fiber cloth (CFC) is used as the substrate. Activated poly(vinylidene fluoride) (PVDF) with titanium dioxide (TiO2) and a silicon dioxide (SiO2) aerogel are electrospun as the top layer. The three-phase interface heterostructure was formed by TiO2, conductive CFC, and the SiO2 aerogel. Its photocatalytic performance is validated by photodegradation of organic dyes in a low-oxygen (O2) water environment. On combining with the capillary condensation of a bilayer structure, P-S-T/C exhibits excellent removal capability for anionic and cationic dyes. Moreover, P-S-T/C exhibits excellent stability and recyclability under simulated sunlight. The mechanism study indicates that the separated photogenerated carriers diffuse to the composite membrane surface rapidly on the three-phase interface of P-S-T/C. The abundant O2 adsorbed on the porous SiO2 aerogel surface acts as an electron (e-)-trapping agent, which can also decrease the work function of the composite materials. Superoxide radicals (•O2 -) play a dominant role in the reaction of photodegradation supported by a free radical-trapping experiment. This work paves a way to design a membrane with photocatalytic performance by constructing the interface heterostructure.

Freeze-thaw-stable high internal phase emulsions stabilized by soy protein isolate and chitosan complexes at pH 3.0 as promising mayonnaise replacers.

The development of cholesterol-free mayonnaise has attracted increasing interest in the food colloid field, due to the potential health concerns as a result of consumption of cholesterol-rich mayonnaise. One effective strategy in this regard is to substitute or partially substitute egg yolk with other organic emulsifiers and stabilizers, without affecting the quality of the product. In the work, we reported an effective strategy to fabricate high freeze-thaw-stability high internal phase emulsions (HIPEs), using complexes of a heated soy protein isolate (SPI) and chitosan (CS) at pH 3.0 as the emulsifiers and stabilizers. The SPI/CS complexes, formed even at a very low CS-to-SPI ratio, e.g., 1:10, showed a high capacity to stabilize HIPEs with a high freeze-thaw stability. Increasing the CS-to-SPI ratio in the complexes resulted in a progressive strengthening of gel network in the corresponding HIPEs, together with a gradual improvement of emulsification performance. The gel network of the HIPEs stabilized by the SPI/CS complexes was mainly maintained by the inter-droplet noncovalent interactions involving the CS molecules. The presence of CS also progressively increased the percentage of adsorbed proteins at the interface, and decreased the surface coverage of proteins at the interface. The high freeze-thaw stability of such HIPEs might be unrelated to the ice crystal formation during the freezing, and was more likely associated with the strong steric repulsion contributed to the adsorbed CS molecules between different droplets. The results indicated that the complexation of heated SPI and CS could provide an effective strategy to facilely fabricate outstanding freeze-thaw-stability HI PEs as potential mayonnaise replacers.

Link Security Situation Identification Method Based on the Ad Hoc Network of Medical Units.

In order to strengthen the management and security status monitoring of the internal network of medical units and make up for security vulnerabilities in time, an ad hoc network link security situation identification method is proposed. According to the architecture of the ad hoc network, it is analyzed that it has the advantages of strong persistence and its own protocol. Combined with the data of detection equipment and security log, the hierarchical acquisition model is used to obtain the situation elements such as port scanning attack and flood attack. The transmission rate factor, forwarding rate factor, dispersion factor, and node aggregation factor are regarded as eigenvectors. We determine the relationship between identity, difference, and opposition, identify the security situation through the description of the node state, and conduct quantitative processing to obtain the final identification result. The experimental results show that the weight value of this method is the same as the standard weight, which can identify the security situation level, obtain the specific situation value, and present a more intuitive identification result.

A biomimetic zeolite-based nanoenzyme contributes to neuroprotection in the neurovascular unit after ischaemic stroke via efficient removal of zinc and ROS.

Zeolite-based nanomaterials have a large number of applications in the field of medicine due to their high porosity, biocompatibility and biological stability. In this study, we designed cerium (Ce)-doped Linde Type A (LTA) zeolite-based nanomaterials (Ce/Zeo-NMs) as a multifunctional mesoporous nanoenzyme to reduce dysfunction of the neurovascular unit (NVU) and attenuate cerebral ischaemia-reperfusion (I/R) injury. Owing to its unique adsorption capacity and mimetic catalytic activities, Ce@Zeo-NMs adsorbed excess zinc ions and exhibited scavenging activity against reactive oxygen species (ROS) induced by acute I/R, thus reshaping the oxidative and zinc microenvironment in the ischaemic brain. In vivo results demonstrated that Ce@Zeo-NMs significantly reduced ischaemic damage to the NVU by decreasing the infarct area, protecting against breakdown of the blood-brain barrier (BBB) via inhibiting the degradation of tight junction proteins (TJPs) and inhibiting activation of microglia and astrocytes in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). Taken together, these findings indicated that Ce@Zeo-NMs may serve as a promising dual-targeting therapeutic agent for alleviating cerebral I/R injury. STATEMENT OF SIGNIFICANCE: Cerium (Ce)-doped Linde Type A zeolite-based nanomaterials (Ce/Zeo-NMs) as a multifunctional mesoporous nanoenzyme were designed for inducing neuroprotection after ischaemic stroke by reducing dysfunction of the neurovascular unit (NVU). Ce@Zeo-NMs had the ability to adsorb excessive Zn2+ and showed mimetic enzymatic activities. As a result, Ce@Zeo-NMs protected against cerebral ischaemia and reduced the damage of NVU by improving the integrity of blood brain barrier (BBB) and inhibiting activation of microglia and astrocytes in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). These findings indicated that Ce@Zeo-NMs may serve as a therapeutic strategy for neuroprotection and functional recovery upon ischaemic stroke onset.

A dual role of human tRNA methyltransferase hTrmt13 in regulating translation and transcription.

Since numerous RNAs and RBPs prevalently localize to active chromatin regions, many RNA-binding proteins (RBPs) may be potential transcriptional regulators. RBPs are generally thought to regulate transcription via noncoding RNAs. Here, we describe a distinct, dual mechanism of transcriptional regulation by the previously uncharacterized tRNA-modifying enzyme, hTrmt13. On one hand, hTrmt13 acts in the cytoplasm to catalyze 2'-O-methylation of tRNAs, thus regulating translation in a manner depending on its tRNA-modification activity. On the other hand, nucleus-localized hTrmt13 directly binds DNA as a transcriptional co-activator of key epithelial-mesenchymal transition factors, thereby promoting cell migration independent of tRNA-modification activity. These dual functions of hTrmt13 are mutually exclusive, as it can bind either DNA or tRNA through its CHHC zinc finger domain. Finally, we find that hTrmt13 expression is tightly associated with poor prognosis and survival in diverse cancer patients. Our discovery of the noncatalytic roles of an RNA-modifying enzyme provides a new perspective for understanding epitranscriptomic regulation.

Position 34 of tRNA is a discriminative element for m5C38 modification by human DNMT2.

Dnmt2, a member of the DNA methyltransferase superfamily, catalyzes the formation of 5-methylcytosine at position 38 in the anticodon loop of tRNAs. Dnmt2 regulates many cellular biological processes, especially the production of tRNA-derived fragments and intergenerational transmission of paternal metabolic disorders to offspring. Moreover, Dnmt2 is closely related to human cancers. The tRNA substrates of mammalian Dnmt2s are mainly detected using bisulfite sequencing; however, we lack supporting biochemical data concerning their substrate specificity or recognition mechanism. Here, we deciphered the tRNA substrates of human DNMT2 (hDNMT2) as tRNAAsp(GUC), tRNAGly(GCC) and tRNAVal(AAC). Intriguingly, for tRNAAsp(GUC) and tRNAGly(GCC), G34 is the discriminator element; whereas for tRNAVal(AAC), the inosine modification at position 34 (I34), which is formed by the ADAT2/3 complex, is the prerequisite for hDNMT2 recognition. We showed that the C32U33(G/I)34N35 (C/U)36A37C38 motif in the anticodon loop, U11:A24 in the D stem, and the correct size of the variable loop are required for Dnmt2 recognition of substrate tRNAs. Furthermore, mammalian Dnmt2s possess a conserved tRNA recognition mechanism.

The Observation of Interchain Motion in Self-Assembled Crystalline Platinum(II) Complexes: An Exquisite Case but By No Means the Only One in Molecular Solids.

In organic and organometallic solids, upon electronic excitation, most intermolecular structural relaxations follow a pathway along the π-π stacking direction or metal-metal bond with significant coupling strength. Differently, we discovered that the self-assembled platinum(II) complexes, Pt(fppz)2, exhibit an unusual interchain contraction. The ground-state and excited-state multiple local minima were distinguished by temperature-dependent excitation/emission spectra, indicating the existence of multiple local minima. The time-resolved emission decay revealed the excited-state structural relaxation lifetime with τobs = 41 ns at 298 K. Temperature-dependent X-ray diffraction analysis showed that the packing geometries contract 0.6 Å along the interchain direction (a-axis) at 50 K compared to the geometries at 298 K. Such structural displacements render the slow internal conversion rate in the excited states. We thus demonstrate the correlation between the packing geometries and the excited-state dynamics of the self-assembled Pt(II) complexes, shedding light on the unique direction of interchain structural deformation of the molecular aggregates.

Baicalin-loaded macrophage-derived exosomes ameliorate ischemic brain injury via the antioxidative pathway.

Baicalin (BA), a strong free radical scavenger, has been demonstrated to exert neuroprotective effects in the treatment of ischemic stroke. However, its clinical application has been limited due to its inability to target the brain and its poor solubility. In this study, we designed novel brain-targeted BA-loaded macrophage-derived exosomes (Exo-BA) to induce neuroprotection against ischemic stroke in animal models. The results revealed that with the help of Exo, the solubility of BA was significantly enhanced. In addition, Exo-BA displayed better brain targeting ability than free BA, as they induced the transfer of more BA into the brain, in a transient middle cerebral artery occlusion/reperfusion (tMCAO) model and permanent middle cerebral artery occlusion (pMCAO) model. Compared with free BA, Exo-BA significantly reduced the generation of reactive oxygen species (ROS) and activated the Nrf2/HO-1 pathway in neurons, thus significantly alleviating cerebral ischemic injury in a stroke model.

Surface-modified engineered exosomes attenuated cerebral ischemia/reperfusion injury by targeting the delivery of quercetin towards impaired neurons.

BACKGROUND: The incidence of ischemic stroke in the context of vascular disease is high, and the expression of growth-associated protein-43 (GAP43) increases when neurons are damaged or stimulated, especially in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R). EXPERIMENTAL: DESIGN: We bioengineered neuron-targeting exosomes (Exo) conjugated to a monoclonal antibody against GAP43 (mAb GAP43) to promote the targeted delivery of quercetin (Que) to ischemic neurons with high GAP43 expression and investigated the ability of Exo to treat cerebral ischemia by scavenging reactive oxygen species (ROS). RESULTS: Our results suggested that Que loaded mAb GAP43 conjugated exosomes (Que/mAb GAP43-Exo) can specifically target damaged neurons through the interaction between Exo-delivered mAb GAP43 and GAP43 expressed in damaged neurons and improve survival of neurons by inhibiting ROS production through the activation of the Nrf2/HO-1 pathway. The brain infarct volume is smaller, and neurological recovery is more markedly improved following Que/mAb GAP43-Exo treatment than following free Que or Que-carrying exosome (Que-Exo) treatment in a rat induced by MCAO/R. CONCLUSIONS: Que/mAb GAP43-Exo may serve a promising dual targeting and therapeutic drug delivery system for alleviating cerebral ischemia/reperfusion injury.

Small-Airway Function Variables in Spirometry, Fractional Exhaled Nitric Oxide, and Circulating Eosinophils Predicted Airway Hyperresponsiveness in Patients with Mild Asthma.

PURPOSE: Patients with variable symptoms suggestive of asthma but with normal forced expiratory volume in 1 second (FEV1) often fail to be diagnosed without a bronchial provocation test, but the test is expensive, time-consuming, risky, and not readily available in all clinical settings. PATIENTS AND METHODS: A cross-sectional study was performed in 692 patients with FEV1≥80% predicted; normal neutrophils and chest high-resolution computed tomography; and recurrent dyspnea, cough, wheeze, and chest tightness. RESULTS: Compared with subjects negative for AHR (n=522), subjects positive for AHR (n=170) showed increased FENO values, peripheral eosinophils (EOS), and R5-R20; decreased FEV1, FEV1/Forced vital capacity (FVC), and forced expiratory flow (FEFs) (P≤.001 for all). Small-airway dysfunction was identified in 104 AHR+ patients (61.17%), and 132 AHR- patients (25.29%) (P<0.001). The areas under the curve (AUCs) of variables used singly for an AHR diagnosis were lower than 0.77. Using joint models of FEF50%, FEF75%, or FEF25%-75% with FENO increased the AUCs to 0.845, 0.824, and 0.844, respectively, significantly higher than univariate AUCs (P <0.001 for all). Patients who reported chest tightness (n=75) had lower FEFs than patients who did not (P<0.001 for all). In subjects with chest tightness, the combination of FEF50% or FEF25%-75% with EOS also increased the AUCs substantially, to 0.815 and 0.816, respectively (P <0.001 for all versus the univariate AUCs). CONCLUSION: FENO combined with FEF50% and FEF25%-75% predict AHR in patients with normal FEV1. FEF25%-75%, FEF50%, or FEF25%-75% together with EOS also can potentially suggest asthma in patients with chest tightness.

Spirometric Changes in Bronchodilation Tests as Predictors of Asthma Diagnosis and Treatment Response in Patients with FEV1 ≥ 80% Predicted.

BACKGROUND: Many patients with mild asthma are undiagnosed and untreated due to the low diagnostic sensitivity of bronchodilation test (BDT). OBJECTIVE: To investigate whether airway reversibility in BDT and fractional exhaled nitric oxide (Feno) can predict the response to antiasthma therapy (RAT) in patients with suspected asthma. METHODS: This open-label, prospective cohort study included patients with chronic recurrent asthma symptoms, normal FEV1, and negative BDT results. Inhaled corticosteroids and long-acting ß agonists were given for 4 weeks. A positive RAT was defined as improved symptoms and an increase of more than 200 mL in FEV1 after inhaled corticosteroid/long-acting ß agonist treatment. Lung tissues from another 19 patients who underwent pneumectomy for lung nodules were also analyzed. RESULTS: Of 110 patients recruited, 102 completed the study. Patients in the positive RAT group had a higher Feno and greater absolute (Δ) and percent (Δ%) improvements in forced vital capacity, FEV1, and forced expiratory flows (FEFs) in BDT than in the negative RAT group. The area under the curves of Feno, ΔFEV1%, ΔFEF25-75% (percent improvement in FEF at 25%-75% of forced vital capacity), and ΔFEF75% (percent improvement in FEF at 75% of forced vital capacity) for positive RAT were 0.703, 0.824, 0.736, and 0.710, with cutoff values of 33 parts per billion and 3.50%, 15.26%, and 26.04%, respectively. A joint model of Feno and ΔFEV1% increased the area under the curve to 0.880. Inflammatory cytokines were higher in the lung tissues of patients with predicted positive RAT than in those with predicted negative RAT. CONCLUSIONS: ΔFEV1% in BDT together with Feno predicted a positive RAT and an asthma diagnosis in patients with a normal FEV1 and negative BDT. Evidence of pathological changes increases the credibility of the predictive model.

[2,2](5,8)Picenophanedienes: Syntheses, Structural Analyses, Molecular Dynamics, and Reversible Intramolecular Structure Conversion.

This study presents an important and efficient synthetic approach to 5,8-dibromo-2,11-di-tert-butylpicene (3), with multigram scale, which was then converted to a new series of picenophanes (6-10). The tub-shaped [2,2](5,8)picenophanediene 8 with two cis-ethylene linkers was explored using X-ray crystallography. The tub-to-tub inversion proceed through the successive bending of the linkers and the barrier for isopropyl-substituted derivative 10 was experimentally estimated to be 18.7 kcal/mol. Picenophanes with a large π-system and semi-rigid structure exhibited anomalous photophysical properties. The ethano-bridged picenophane shows the weak exciton delocalization while the cis-ethylene-bridged picenophane exhibits dual emission rendered by the weakly delocalized exciton and excimer. With the aid of the ultrafast time-resolved emission spectroscopy, the mechanism of the excimer formation is resolved, showing a unique behavior of two-state reversible reaction with fast structural deformation whose lifetime is around 20 ps at 298 K. This work demonstrates that the slight difference in the bridge of tub-shaped picenophanes renders distinct photophysical behavior, revealing the potential of harnessing inter-moiety reaction in the picenophane systems.

Highly Emissive Dinuclear Platinum(III) Complexes.

Dinuclear Pt(III) complexes were commonly reported to have short-lived lowest-lying triplet states, resulting in extremely weak or no photoluminescence. To overcome this obstacle, a new series of dinuclear Pt(III) complexes, named Pt2a-Pt2c, were strategically designed and synthesized using donor (D)-acceptor (A)-type oxadiazole-thiol chelates as bridging ligands. These dinuclear Pt(III) complexes possess a d7-d7 electronic configuration and exhibit intense phosphorescence under ambient conditions. Among them, Pt2a exhibits orange phosphorescence maximized at 618 nm in degassed dichloromethane solution (Φp ≈ 8.2%, τp ≈ 0.10 µs) and near-infrared (NIR) emission at 749 nm (Φp ≈ 10.1% τp ≈ 0.66 µs) in the crystalline powder and at 704 nm (Φp ≈ 33.1%, τp ≈ 0.34 µs) in the spin-coated neat film. An emission blue-shifted by more than 3343 cm-1 is observed under mechanically ground crystalline Pt2a, affirming intermolecular interactions in the solid states. Time-dependent density functional theory (TD-DFT) discloses the lowest-lying electronic transition of Pt2a-Pt2c complexes to be a bridging ligand-metal-metal charge transfer (LMMCT) transition. The long-lived triplet states of these dinuclear platinum(III) complexes may find potential use in lighting. Employing Pt2a as an emitter, high-performance organic light-emitting diodes (OLEDs) were fabricated with NIR emission at 716 nm (η = 5.1%), red emission at 614 nm (η = 8.7%), and white-light emission (η = 11.6%) in nondoped, doped (in mCP), and hybrid (in CzACSF) devices, respectively.