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PURPOSE: The SPECTRUM 4 and 3 studies assessed the intraocular pressure (IOP)-lowering efficacy and safety of omidenepag isopropyl (OMDI) 0.002% vs timolol 0.5% in patients with glaucoma or ocular hypertension (OHT). DESIGN: Phase 3, randomized, controlled, double-masked, noninferiority studies. METHODS: Multicenter studies in the US. Inclusion criteria for adults ≥ 18 years (SPECTRUM 4 [N = 409] and 3 [N = 413]) were open-angle glaucoma or OHT, and IOP ≥ 22 mm Hg and ≤ 34 mm Hg; and for pediatric patients < 18 years (N = 13, SPECTRUM 3) were pediatric glaucoma or OHT. The primary objective in both studies was OMDI noninferiority to timolol in reducing IOP (3 months). SPECTRUM 3 included an additional 9 months of OMDI treatment. Safety evaluations were of ocular/non-ocular adverse events (AEs). RESULTS: The IOP-lowering range of OMDI remained consistent in SPECTRUM 4 and 3 (-5.6 to -5.9 vs -5.3 to -5.7 mm Hg, respectively); however, timolol efficacy varied (-5.4 to -6.1 vs -6.4 to -7.0 mm Hg, respectively). OMDI noninferiority was achieved in SPECTRUM 4. Efficacy was maintained with 12-month treatment in SPECTRUM 3. Both studies reported more ocular AEs with OMDI, but lower rates of appearance-altering AEs vs timolol. No new safety concerns were identified. Rates of macular edema in pseudophakic patients increased with prolonged OMDI exposure. CONCLUSIONS: SPECTRUM 4 and 3 demonstrated consistent 3-month IOP-lowering efficacy and safety of OMDI vs timolol in patients with glaucoma or OHT. The 12-month data from SPECTRUM 3 suggest OMDI may have long-term benefits in patients with glaucoma or OHT.
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Anti-Hipertensivos , Glaucoma de Ângulo Aberto , Pressão Intraocular , Hipertensão Ocular , Soluções Oftálmicas , Timolol , Tonometria Ocular , Humanos , Timolol/uso terapêutico , Pressão Intraocular/efeitos dos fármacos , Pressão Intraocular/fisiologia , Hipertensão Ocular/tratamento farmacológico , Hipertensão Ocular/fisiopatologia , Método Duplo-Cego , Feminino , Masculino , Anti-Hipertensivos/uso terapêutico , Glaucoma de Ângulo Aberto/tratamento farmacológico , Glaucoma de Ângulo Aberto/fisiopatologia , Pessoa de Meia-Idade , Idoso , Resultado do Tratamento , Adulto , Adolescente , Adulto Jovem , Criança , Glicina/análogos & derivados , Pirazóis , PiridinasRESUMO
Dry eye disease (DED) is one of the most common ocular surface disorders. All DED involves an imbalance between tear production and evaporation. Most cases of DED are driven by excessive evaporation, which is often associated with meibomian gland dysfunction (MGD). In evaporative DED, a deficient tear film lipid layer is believed to lead to increased tear evaporation, inflammation, and ocular surface damage. Most prescription treatments for DED address signs and symptoms by targeting tear production and/or inflammation, but they do not address excessive evaporation. Perfluorohexyloctane (PFHO) ophthalmic solution (MIEBO™; Bausch + Lomb) is a water-free, single-ingredient, preservative-free prescription eye drop that directly targets tear evaporation and is approved by the FDA to treat the signs and symptoms of DED. Results from preclinical studies indicate that PFHO has a high oxygen carrying capacity, may reduce friction on blinking, and spreads quickly over the tear film surface to form a monolayer that inhibits evaporation. These effects can lead to stabilization of the tear film to promote ocular surface healing. Further, PFHO was detected in tears for at least 6 hours in a rabbit pharmacokinetic study, and results indicate that it may improve lipid layer thickness and quality. In 2 pivotal phase 3 trials in patients with DED and clinical signs of MGD (GOBI [NCT04139798] and MOJAVE [NCT04567329]), treatment with PFHO consistently met primary efficacy end points related to DED signs and symptoms (total corneal fluorescein staining and eye dryness, respectively) and was well tolerated. Compared with use of hypotonic saline solution, instillation of PFHO led to significant improvements in signs and symptoms in as early as 2 weeks. In a long-term, open-label safety extension study, efficacy of PFHO was sustained over 12 months, and the safety profile was consistent with those of previous studies. Clinical trial results indicate that treatment with PFHO effectively and consistently reduces the signs and symptoms of DED.
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Síndromes do Olho Seco , Animais , Humanos , Coelhos , Soluções Oftálmicas/uso terapêutico , Síndromes do Olho Seco/tratamento farmacológico , Inflamação , LipídeosRESUMO
PURPOSE: Dry eye disease (DED) symptoms can negatively impact quality of life (QoL). AR-15512, a transient receptor potential melastatin 8 (TRPM8) agonist, was evaluated as a potential therapy for DED. METHODS: In a Phase 2b study, patients with DED were randomized 1:1:1 to 0.0014% AR-15512, 0.003% AR-15512, or vehicle twice daily for 12 weeks. Eligibility criteria included DED signs and symptoms of prespecified severity levels. Outcomes assessed were DED signs (Schirmer score ± anesthetic, ocular surface staining, hyperemia), symptoms (Ocular Discomfort [ODS-VAS], Symptoms Assessment iN Dry Eye [SANDE], Eye Dryness-VAS, Ocular Pain-VAS), QoL-VAS, and adverse events. Co-primary endpoints were changes from baseline in ODS-VAS and anesthetized Schirmer score at Day 28. RESULTS: 0.003% AR-15512 (n = 122) was associated with early and sustained improvements in unanesthetized Schirmer score (Days 1 and 14, p < 0.0001), as well as improvements in ocular surface staining (Days 14 and 84, p ≤ 0.0365) and hyperemia (Day 84, p < 0.0215). Statistically significant improvements in symptoms were observed for the 0.003% concentration on SANDE (Days 14, 28, and 84, p ≤ 0.0254), ODS-VAS (Day 84, p = 0.0281), Eye Dryness-VAS (Day 84, p = 0.0302), and multiple QoL measures (Days 14, 28, and 84, p < 0.05). There were no significant differences between active and vehicle groups for the co-primary endpoints. The most common adverse events were burning and stinging upon instillation. CONCLUSIONS: Although predefined co-primary study endpoints were not met, AR-15512 demonstrated statistically significant improvements in DED signs, symptoms, and disease-related QoL.
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Síndromes do Olho Seco , Hiperemia , Canais de Cátion TRPM , Humanos , Método Duplo-Cego , Síndromes do Olho Seco/tratamento farmacológico , Proteínas de Membrana , Qualidade de Vida , Lágrimas , Canais de Cátion TRPM/agonistasRESUMO
OBJECTIVES: This study evaluated the safety of topical lipoic acid choline ester (UNR844, 1.5%) ophthalmic solution and its efficacy in improving distance-corrected near visual acuity (DCNVA) in subjects with presbyopia. SUBJECTS AND METHODS: This was a prospective, randomized, double-masked, and multicentre clinical trial. Subjects with a diagnosis of presbyopia (n = 75) were randomized 2:1 to UNR844 or placebo. On days 1-7, all subjects were dosed unilaterally (twice a day, b.i.d.) in their non-dominant eye to ensure safety and tolerability prior to days 8-91 when dosing was changed to bilateral (b.i.d.). Clinical assessments, including DCNVA and adverse events (AEs), were recorded at each study visit. Patients who completed the study were recruited into a non-interventional follow-up study that monitored them until 7 months after their final UNR844 exposure. The primary endpoints were safety and the mean change in DCNVA from baseline in the study eye. RESULTS: UNR844 administration (n = 50) produced no safety concerns and was well-tolerated, with no clinically-relevant changes in best-corrected distance visual acuity, pupil size, intraocular pressure, or discontinuations due to adverse events. DCNVA improved in the study eye in the UNR844 group compared to placebo during the 91 days of treatment [UNR844 vs. placebo, mean change in LogMAR (SD); -0.159 (0.120) vs. -0.079 (0.116)]. Bilateral DCNVA improved, with 53.1% UNR844 vs. 21.7% placebo subjects gaining ≥10 letters. Improvements in DCNVA were sustained at 5 and 7 months after UNR844 dosing ceased. CONCLUSIONS: These results support further development of UNR844 ophthalmic solution for the treatment of presbyopia.
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Presbiopia , Ácido Tióctico , Colina , Ésteres , Seguimentos , Humanos , Soluções Oftálmicas , Presbiopia/tratamento farmacológico , Estudos Prospectivos , Acuidade VisualRESUMO
Introduction The objectives were to characterise the particle size distribution of aerosols generated by standard dental aerosol generating procedures (AGPs) and to assess the impact of aerosol-management interventions on 'fallow time'. Interventions included combinations of high-volume intraoral suction (HVS[IO]), high-volume extraoral suction (HVS[EO]) and an air cleaning system (ACS).Method A sequence of six AGPs were performed on a phantom head. Real-time aerosol measurements (particle size range 0.0062-9.6 µm) were acquired from six locations within a typical dental treatment room (35 m3).Results The majority (>99%) of AGP particles were <0.3 µm diameter and remained at elevated levels around the dental team during the AGPs. With no active aerosol-management interventions, AGP particles were estimated to remain above the baseline range for up to 30 minutes from the end of the sequence of procedures.Conclusions The results emphasise the importance of personal protection equipment, particularly respiratory protection. Use of HVS(IO), either alone or in combination with the ACS, reduced particle concentrations to baseline levels on completion of AGPs. These data indicate potential to eliminate fallow time. The study was performed using a phantom head so confirmatory studies with patients are required.
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Dry eye disease (DED) is a multifactorial disease of the ocular surface characterized by loss of homeostasis of the tear film and accompanied by symptoms such as ocular discomfort and visual disturbance. DED is one of the most common reasons for seeking medical care in the United States and across the world. Despite this, there are a limited number of pharmacologic therapies for the treatment of DED in the United States and Europe. This review examines the different pivotal trials for DED medications and the impact the vehicle in each trial.In recent clinical trials, the vehicle of the active formulation of the medication is often used as the active comparator. A literature review of published dry eye clinical trials was performed to identify the pivotal clinical trials of DED medications and to compare treatment effect and further understand the impact of the vehicle on clinical trial outcomes.The pivotal clinical trials for the currently approved treatments for dry eye have widely varying study designs. The variations include differences in inclusion criteria, outcome measures and efficacy endpoints, and whether or not the use of concomitant artificial tears is allowed. These differences make it difficult for accurate comparisons to be made between DED medications. Each trial demonstrated that the vehicle alone has some beneficial effect on signs and symptoms of dry eye disease.This review discusses the varying trial designs and vehicles used in the pivotal studies for the four approved dry eye medications in the United States and Europe, as well as novel vehicles under development and clinical trial recommendations.
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Ciclosporina/uso terapêutico , Síndromes do Olho Seco/tratamento farmacológico , Veículos Farmacêuticos/uso terapêutico , Fenilalanina/análogos & derivados , Sulfonas/uso terapêutico , Administração Oftálmica , Ensaios Clínicos como Assunto , Síndromes do Olho Seco/diagnóstico , Síndromes do Olho Seco/fisiopatologia , Emulsões , Humanos , Soluções Oftálmicas , Fenilalanina/uso terapêuticoRESUMO
PURPOSE: To evaluate the safety and effectiveness of the intranasal tear neurostimulator (ITN) in improving dry eye symptoms assessed in a controlled adverse environment (CAE®). METHODS: Study 1: Multicenter, subject-masked, randomized-sequence, crossover design. Single intranasal (active) and extranasal (control) ITN administration during CAE exposure. Study 2: Single-arm, open-label design. Intranasal ITN administration ≥2 times/day for 45 days, CAE assessment at days 0 and 45. In both studies, upon CAE entry, and every 5â¯min thereafter, subjects assessed eye dryness score (visual analog scale, 0-100â¯mm; EDS-VAS), and ocular discomfort score (ODS; Ora Calibra™, 0-4), for ≈2â¯h. Study 1: when ODS was ≥3â¯at 2 consecutive timepoints, subjects applied ITN intranasally or extranasally for ≈3â¯min, and again when achieving the same ODS criteria in randomized sequence. Study 2: days 0 and 45, ITN was applied for ≈3â¯min employing the same ODS criteria as Study 1. RESULTS: Study 1: Significantly greater pre- to post-application reductions in mean [SEM] EDS (-16.5 [1.7] vs -3.1 [1.7], Pâ¯<â¯0.0001) and ODS (-0.93 [0.08] vs -0.34 [0.08], Pâ¯<â¯0.0001; nâ¯=â¯143) with intranasal vs extranasal stimulation. Study 2: On day 0 (nâ¯=â¯52) and day 45 (nâ¯=â¯48), significant pre- to post-application reductions in mean [SEM] EDS (-15.9 [2.7] and -15.2 [2.4]; Pâ¯<â¯0.0001), and ODS (-1.3 [0.2] and -1.3 [0.1]; Pâ¯<â¯0.0001). Few device-related adverse events were reported, none serious. CONCLUSIONS: Acute symptom relief is significant with the ITN and remains undiminished after daily use.
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Síndromes do Olho Seco , Estudos Cross-Over , Síndromes do Olho Seco/terapia , Terapia por Estimulação Elétrica , Humanos , LágrimasRESUMO
PURPOSE: The intranasal tear neurostimulator (ITN) activates the nasolacrimal pathway, which is involved with basal and bolus tear secretion. These studies characterized the acute and long-term effectiveness of the ITN in stimulating tear production in subjects with dry eye disease (DED). METHODS: Study 1: Randomized, double-masked, dual-controlled, 1-day crossover. Study 2: Single-arm, open-label, 180-day prospective cohort. Eligible subjects had basal unstimulated Schirmer test (with anesthesia) ≤10â¯mm and intranasal cotton swab-stimulated Schirmer test at least 7â¯mm greater in the same eye, and Ocular Surface Disease Index® ≥13 andâ¯≥â¯23, in Studies 1 and 2, respectively. Study 1: Subjects (nâ¯=â¯48) received three randomized test applications: active intranasal, extranasal (active control), and sham intranasal (inactive control) stimulation, 3â¯min/application with 1-hour minimum between applications. Primary outcome measure was the difference in Schirmer test scores during active intranasal and control applications. Study 2: Subjects (nâ¯=â¯97) performed intranasal neurostimulation for ≤3â¯min/application, 2-10 times/day. Primary outcome measure was the difference in Schirmer scores (stimulated minus unstimulated) at day 180. Both studies recorded device-related adverse events (AEs). RESULTS: Study 1: Schirmer scores (mean⯱â¯SEM) were significantly greater (pâ¯<â¯0.0001) with active intranasal (25.3⯱â¯1.5â¯mm) vs extranasal (9.5⯱â¯1.2â¯mm) and sham (9.2⯱â¯1.1â¯mm) applications. Study 2: Schirmer scores were significantly greater (pâ¯<â¯0.0001) with ITN stimulation vs unstimulated at day 180 (17.3⯱â¯1.3â¯mm vs 7.9⯱â¯0.7â¯mm). No serious device-related AEs were reported in either study. CONCLUSION: The ITN was well-tolerated and effective in stimulating tear production with acute and long-term use in DED. CLINICALTRIALS. GOV IDENTIFIER: NCT02680158 and NCT02526290.
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Síndromes do Olho Seco/terapia , Terapia por Estimulação Elétrica/instrumentação , Aparelho Lacrimal/metabolismo , Mucosa Nasal/inervação , Lágrimas/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Cross-Over , Método Duplo-Cego , Síndromes do Olho Seco/metabolismo , Desenho de Equipamento , Feminino , Seguimentos , Humanos , Aparelho Lacrimal/inervação , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do TratamentoRESUMO
Recently, ultrathin two-dimensional (2D) nanomaterials have attracted considerable research interest in biomedical applications, owing to their intriguing quantum size and surface effects. In this work, a one-step "bottom-up" method is developed to prepare rare-earth (Gd3+ and Yb3+) co-doped layered double hydroxide (LDH) monolayer nanosheets, with a precisely controlled composition and uniform morphology. Due to the successful introduction of Gd3+ and Yb3+ into the LDH host layer, the Gd&Yb-LDH monolayer nanosheets exhibit excellent magnetic resonance (MR)/X-ray computed tomography (CT) dual-mode imaging functionality. Moreover, the Gd&Yb-LDH monolayer nanosheets achieve an ultrahigh loading of a chemotherapeutic drug (SN38) with a loading content (LC) of 925%, which is a one order of magnitude enhancement compared with previously reported delivery systems of hydrophobic drugs. Interestingly, by further combination with indocyanine green (ICG), in vivo tri-mode imaging, including CT, MR and near infrared fluorescence (NIRF) imaging, is achieved, which enables a noninvasive visualization of cancer cell distribution with deep spatial resolution and high sensitivity. In addition, in vitro and in vivo therapeutic evaluations demonstrate an extremely high tri-mode synergetic anticancer activity and superior biocompatibility of SN38&ICG/Gd&Yb-LDH. Therefore, this work demonstrates a paradigm for the synthesis of novel multifunctional 2D monolayer materials via a facile "bottom-up" route, which shows promising applications in cancer synergetic theranostics.
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An ultrathin photosensitizer was prepared by immobilization of chlorin e6 (Ce6) and carbon dots (CDs) onto layered double hydroxide (LDH) nanosheets, which exhibited excellent fluorescence imaging and photodynamic therapy performance toward cancer theranostics.
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Recently, theranostic has drawn tremendous attention by virtue of the nanotechnology development and new material exploration. Herein, we reported a novel theranostic system by loading Au nanoclusters (AuNCs) and Chlorin e6 (photosensitizer, Ce6) onto the monolayer nanosheet surface of Gd-doped layered double hydroxide (Gd-LDH). The as-prepared Ce6&AuNCs/Gd-LDH exhibits a largely enhanced fluorescence quantum yield (QY) of 18.5% relative to pristine AuNCs (QYâ¯=â¯3.1%) as well as superior T1 magnetic resonance imaging (MRI) performance (r1â¯=â¯17.57â¯mM-1s-1) compared with commercial MRI contrast agent (Gd(III)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (Gd-DOTA): r1â¯≈â¯3.4â¯mM-1s-1), resulting from a synergistic effect between AuNCs and Gd-LDH. In addition, both in vitro and in vivo therapeutic evaluations demonstrate an efficient dual-modality imaging guided anticancer performance, especially the synergetic enhanced magnetic resonance/fluorescence (MR/FL) visualization of tumor site. Therefore, this work demonstrates a successful paradigm for the design and preparation of LDHs monolayer-based theranostic material, which holds great promises in practical applications.
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Hidróxido de Alumínio , Hidróxido de Magnésio , Imagem Multimodal , Fotoquimioterapia , Nanomedicina Teranóstica , Hidróxido de Alumínio/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Meios de Contraste/química , Humanos , Hidróxido de Magnésio/química , Imageamento por Ressonância Magnética/métodos , Nanopartículas Metálicas/química , Imagem Multimodal/métodos , Neoplasias/diagnóstico por imagem , Neoplasias/terapia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Nanomedicina Teranóstica/métodosRESUMO
2D nanomaterials have attracted considerable research interest in drug delivery systems, owing to their intriguing quantum size and surface effect. Herein, Gd3+ -doped monolayered-double-hydroxide (MLDH) nanosheets are prepared via a facile bottom-up synthesis method, with a precisely controlled composition and uniform morphology. MLDH nanosheets as drug carrier are demonstrated in coloading of doxorubicin and indocyanine green (DOX&ICG), with an ultrahigh drug loading content (LC) of 797.36% and an encapsulation efficiency (EE) of 99.67%. This is, as far as it is known, the highest LC level at nearly 100% of EE among previously reported 2D drug delivery systems so far. Interestingly, the as-prepared DOX&ICG/MLDH composite material shows both pH-controlled and near-infrared-irradiation-induced DOX release, which holds a promise in stimulated drug release. An in vivo dual-mode imaging, including near-infrared fluorescence and magnetic resonance imaging, enables a noninvasive visualization of distribution profiles at the tumor site. In addition, in vitro and in vivo therapeutic evaluations demonstrate an excellent trimode synergetic anticancer activity and superior biocompatibility of DOX&ICG/MLDH. Therefore, MLDH nanosheets provide new perspectives in the design of multifunctional nanomedicine, which shows promising applications in controlled drug delivery and cancer theranostics.
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Neoplasias , Doxorrubicina , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Humanos , Nanomedicina TeranósticaRESUMO
Fluorescent carbon nanomaterials have drawn tremendous attention for their intriguing optical performances, but their employment in solid-state luminescent devices is rather limited as a result of aggregation-induced photoluminescence quenching. Herein, ultrathin carbon nitride (CN) is synthesized within the 2D confined region of layered double hydroxide (LDH) via triggering the interlayer condensation reaction of citric acid and urea. The resulting CN/LDH phosphor emits strong cyan light under UV-light irradiation with an absolute solid-state quantum yield (SSQY) of 95.9 ± 2.2%, which is, to the best of our knowledge, the highest value of carbon-based fluorescent materials ever reported. Furthermore, it exhibits a strong luminescence stability toward temperature, environmental pH, and photocorrosion. Both experimental studies and theoretical calculations reveal that the host-guest interactions between the rigid LDH matrix and interlayer carbon nitride give the predominant contribution to the unprecedented SSQY and stability. In addition, prospective applications of the CN/LDH material are demonstrated in both white light-emitting diodes and upconversion fluorescence imaging of cancer cells.
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Selective oxidation of alcohols to aldehydes plays an important role in perfumery, pharmaceuticals, and agrochemicals industry. Different from traditional catalysis or photocatalytic process, here we report an effective photoelectrochemical (PEC) approach for selective anaerobic oxidation of alcohols accompanied with H2 production by means of solar energy. By using TiO2 nanowires modified with graphitic carbon layer as photoanode, benzyl alcohol (BA) has been oxidized to benzaldehyde with high efficiency and selectivity (>99 %) in aqueous media at room temperature, superior to individual electrocatalytic or photocatalytic processes. Moreover, this PEC synthesis method can be effectively extended to the oxidation of several other aryl alcohols to their corresponding aldehydes under mild conditions. The electron spin resonance (ESR) results indicate the formation of intermediate active oxygen (O2.- ) on the photoanode, which further reacts with alcohols to produce final aldehyde compounds.
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A hierarchical CoNi-sulfide nanosheet array is fabricated via an in situ reduction of CoNi-layered double hydroxide (LDH) nanosheets, then a vulcanization process. The material inherits the morphology of the LDH precursor, consisting of well-distributed CoNi-alloy@CoNi-sulfide nanoparticles with a core-shell structure, and demonstrates promising performance toward hydrazine electrooxidation.
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The thermal topotactic transformation mechanism of MgAl layered double hydroxides (LDHs) is investigated by a combined theoretical and experimental study. Thermogravimetric differential thermal analysis (TG-DTA) results reveal that the LDH phase undergoes four key endothermic events at 230, 330, 450, and 800 °C. DFT calculations show that the LDH decomposes into CO2 and residual O atoms via a monodentate intermediate at 330 °C. At 450 °C, the metal cations almost maintain their original distribution within the LDH(001) facet during the thermal dehydration process, but migrate substantially along the c-axis direction perpendicular to the (001) facet; this indicates that the metal arrangement/dispersion in the LDH matrix is maintained two-dimensionally. A complete collapse of the layered structure occurs at 800 °C, which results in a totally disordered cation distribution and many holes in the final product. The structures of the simulated intermediates are highly consistent with the observed inâ situ powder XRD data for the MgAl LDH sample calcined at the corresponding temperatures. Understanding the structural topotactic transformation process of LDHs would provide helpful information for the design and preparation of metal/metal oxides functional materials derived from LDH precursors.
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Oxygen vacancy on the surface of metal oxides is one of the most important defects which acts as the reactive site in a variety of catalytic reactions. In this work, operando spectroscopy methodology was employed to study the CO2 methanation reaction catalyzed by Ru/CeO2 (with oxygen vacancy in CeO2) and Ru/α-Al2O3 (without oxygen vacancy), respectively, so as to give a thorough understanding on active site dependent reaction mechanism. In Ru/CeO2 catalyst, operando XANES, IR, and Raman were used to reveal the generation process of Ce(3+), surface hydroxyl, and oxygen vacancy as well as their structural evolvements under practical reaction conditions. The steady-state isotope transient kinetic analysis (SSITKA)-type in situ DRIFT infrared spectroscopy undoubtedly substantiates that CO2 methanation undergoes formate route over Ru/CeO2 catalyst, and the formate dissociation to methanol catalyzed by oxygen vacancy is the rate-determining step. In contrast, CO2 methanation undergoes CO route over Ru surface in Ru/α-Al2O3 with the absence of oxygen vacancy, demonstrating active site dependent catalytic mechanism toward CO2 methanation. In addition, the catalytic activity evaluation and the oscillating reaction over Ru/CeO2 catalyst further prove that the oxygen vacancy catalyzes the rate-determining step with a much lower activation temperature compared with Ru surface in Ru/α-Al2O3 (125 vs 250 °C).
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Gold nanoclusters (Au NCs) as ultrasmall fluorescent nanomaterials possess discrete electronic energy and unique physicochemical properties, but suffer from relatively low quantum yield (QY) which severely affects their application in displays and imaging. To solve this conundrum and obtain highly-efficient fluorescent emission, 2D exfoliated layered double hydroxide (ELDH) nanosheets were employed to localize Au NCs with a density as high as 5.44 × 10(13) cm(-2), by virtue of the surface confinement effect of ELDH. Both experimental studies and computational simulations testify that the excited electrons of Au NCs are strongly confined by MgAl-ELDH nanosheets, which results in a largely promoted QY as well as prolonged fluorescence lifetime (both â¼7 times enhancement). In addition, the as-fabricated Au NC/ELDH hybrid material exhibits excellent imaging properties with good stability and biocompatibility in the intracellular environment. Therefore, this work provides a facile strategy to achieve highly luminescent Au NCs via surface-confined emission enhancement imposed by ultrathin inorganic nanosheets, which can be potentially used in bio-imaging and cell labelling.