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1.
CNS Neurosci Ther ; 30(3): e14651, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38432692

RESUMO

AIMS: To investigate the risk factors for early-onset psychosis in Parkinson's disease (PD) in a cohort of patients from the Parkinson's Progression Markers Initiative. METHODS: Longitudinal data on motor and non-motor features, dopamine transporter (DAT) imaging, and cerebrospinal fluid (CSF) measurements were collected. The survival probability of psychotic symptoms, potential risk factors for psychosis development over a 5-year follow-up period, and the performance of the prediction model were evaluated. RESULTS: Among the 338 newly diagnosed patients with PD, 83 developed psychotic symptoms. Gastrointestinal autonomic dysfunction, presence of probable rapid-eye-movement sleep behavior disorder, and the ratio Aß42: total-tau could independently predict onset of psychosis in PD (hazard ratio (HR) = 1.157, 95% confidence interval (CI) 1.022-1.309, p = 0.021, HR = 2.596, 95% CI 1.287-5.237, p = 0.008, and HR = 0.842, 95% CI 0.723-0.980, p = 0.027, respectively). The combined model integrating baseline clinical predictors, DAT imaging, and CSF measurements achieved better sensitivity than the clinical predictors alone (area under the curve = 0.770 [95% CI 0.672-0.868] vs. 0.714 [95% CI 0.625-0.802], p = 0.098). CONCLUSION: We identified clinical and CSF predictors of early-onset psychosis in patients with PD. Our study provides evidence and implications for prognostic stratification and therapeutic approaches for PD psychosis.


Assuntos
Doenças do Sistema Nervoso Autônomo , Doença de Parkinson , Transtornos Psicóticos , Humanos , Doença de Parkinson/diagnóstico , Doença de Parkinson/diagnóstico por imagem , Estudos de Coortes , Transtornos Psicóticos/diagnóstico por imagem , Transtornos Psicóticos/etiologia , Fatores de Risco
2.
Artigo em Inglês | MEDLINE | ID: mdl-38093699

RESUMO

OBJECTIVE: This study aimed to explore the association between slow-wave sleep and the progression of motor and nonmotor symptoms in patients with PD. METHODS: Data were collected from the Parkinson's Progression Markers Initiative study. Slow-wave sleep, also known as deep non-rapid eye movement (DNREM) sleep, was objectively assessed using the Verily Study Watch. Motor function was assessed using the Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part III score, Hoehn and Yahr stage, freezing of gait, motor fluctuations, and dyskinesia severity. Comprehensive assessments were conducted on nonmotor symptoms, including depression, anxiety, global cognitive function, and autonomic dysfunction. Statistical analyses involved repeated-measures analysis of variance and linear regression. RESULTS: A total of 102 patients with PD were included in the study, with a median follow-up duration of 3.4 years. In the long DNREM sleep duration group (n = 55), better motor function (DNREM × time interaction: F(1,100) = 4.866, p = 0.030), less severe sexual dysfunction (p = 0.026), and improved activities of daily living (p = 0.033) were observed at the last follow-up visit compared with the short DNREM sleep duration group (n = 47). Reduced DNREM sleep duration is a risk factor for motor progression (ß = -0.251, p = 0.021; 95% confidence interval = -0.465 to -0.038). INTERPRETATION: The findings suggest an association between longer DNREM sleep duration and slower motor and nonmotor progression in patients with PD.

3.
Diabetes Res Clin Pract ; 206: 110996, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37956943

RESUMO

OBJECTIVE: To systematically evaluate the prevalence of Diabetes Distress (DD) in type 2 diabetes mellitus (T2DM) patients in China. METHODS: The PubMed, PsycInfo, Web of Science, The Cochrane Library, EMBASE, China Knowledge Resource in Integrated Database (CNKI), WanFang Database, Weipu Database (VIP), and Chinese Biomedical Database (CBM) electronic databases were searched from inception to August 2022, for cross-sectional studies, that reported prevalence of DD. RESULTS: This study included 55 articles involving 13,160 patients with T2DM. The pooled prevalence of DD was 53.2%. The results of the subgroup analysis showed that among the five regions in China, the highest prevalence of DD was observed in Central China (66%), while the lowest prevalence was recorded in North China (23%). The highest prevalence of DD was 82% in unmarried people. while the lowest prevalence of DD among outpatients was as low as 42%. The results of meta-regression showed that there was no correlation between the prevalence of DD and the year of publication, the average age of the patients, or the duration of the disease. CONCLUSION: More than half of T2DM patients in China may suffer from DD, which is not conducive to the self-management of diabetes patients. The burden on the healthcare system and the burden of disease on individual patients may increase as a result. Medical staff should pay attention to the monitoring and management of the mental health status of patients with T2DM.


Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/epidemiologia , Estudos Transversais , Prevalência , Projetos de Pesquisa , China/epidemiologia
4.
Environ Pollut ; 336: 122384, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37586680

RESUMO

Rare earth elements (REEs) are emerging micropollutants in aquatic environments. In this study, concentrations of REEs and major elements, and mineralogical compositions of sediments from lower reaches of the Xiangjiang River (China) were analyzed using ICP-MS technique. The results suggested that sediments were characterized by terrigenous compositions TiO2, SiO2, Al2O3, K2O, Na2O and P2O, and contained high concentrations of REEs with mean total REE concentrations (∑REE) of 318.7 mg/kg. REEs were moderately enriched in upper river sediments, and slightly or less enriched in downriver sediments. The normalized REE distribution pattern for sediments was characterized by flat shalelike and Eu depleted V-shape REE patterns, which indicated REEs in sediments were lithologically contributed from sedimentary rocks and granites distributed in the watershed respectively. REEs in sediments were hosted mainly in Fe-Mn oxides, and sulfide and organic matters that were characterized by middle REEs (MREE) enrichments relative to light REEs (LREE) and heavy REEs (HREE), and the distribution and differentiation of REEs in sediments were controlled by clays, Fe-Mn oxides, organic matters and finer grains; and also by accessory minerals (e.g., zircon) from granite. The distribution features of REEs in sediments and BCR extraction results suggested that the sediment REE enrichment resulted from additional REE input from anthropogenic sources, including those in discharges from sulfide-ore smelting industries at Zhuzhou city and from phosphate fertilizer plants at Xiangtan city along the river. Thus, sediments were contaminated with REEs in moderate degree in upper river area, and REE contamination was then formed by superimposing anthropogenic REEs on lithological residues. Finally, concentrations of Ce > 100 mg/kg, Gd > 8.12 mg/kg, ∑REE >274.9 mg/kg, ∑LREE >252.3 mg/kg and ∑HREE >28.8 mg/kg here were recommended as the REE contamination levels that represented as REE indices for identifying and rating REE contamination in this mining impacted river.


Assuntos
Metais Terras Raras , Poluentes Químicos da Água , Dióxido de Silício , Rios/química , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Metais Terras Raras/análise , China , Sulfetos
5.
Front Aging Neurosci ; 15: 1142558, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36926634

RESUMO

Background and objective: Cognitive impairment (CI) is a substantial contributor to the disability associated with Parkinson's disease (PD). We aimed to assess the clinical features and explore the underlying biomarkers as predictors of CI in patients with newly diagnosed PD (NDPD; less than 2 years). Methods: We evaluated the cognitive function status using the Montreal Cognitive Assessment (MoCA) and a battery of neuropsychological tests at baseline and subsequent annual follow-up for 5 years from the Parkinson's Progression Markers Initiative (PPMI) database. We assessed the baseline clinical features, apolipoprotein (APO) E status, ß-glucocerebrosidase (GBA) mutation status, cerebrospinal fluid findings, and dopamine transporter imaging results. Using a diagnosis of CI (combined mild cognitive impairment and dementia) developed during the 5-year follow-up as outcome measures, we assessed the predictive values of baseline clinical variables and biomarkers. We also constructed a predictive model for the diagnosis of CI using logistic regression analysis. Results: A total of 409 patients with NDPD with 5-year follow-up were enrolled, 232 with normal cognitive function at baseline, and 94 patients developed CI during the 5-year follow-up. In multivariate analyses, age, current diagnosis of hypertension, baseline MoCA scores, Movement disorder society Unified PD Rating Scale part III (MDS-UPDRS III) scores, and APOE status were associated with the development of CI. Predictive accuracy of CI using age alone improved by the addition of clinical variables and biomarkers (current diagnosis of hypertension, baseline MoCA scores, and MDS-UPDRS III scores, APOE status; AUC 0.80 [95% CI 0.74-0.86] vs. 0.71 [0.64-0.77], p = 0.008). Cognitive domains that had higher frequencies of impairment were found in verbal memory (12.6 vs. 16.8%) and attention/processing speed (12.7 vs. 16.9%), however, no significant difference in the prevalence of CI at annual follow-up was found during the 5-year follow-up in NDPD patients. Conclusion: In NDPD, the development of CI during the 5-year follow-up can be predicted with good accuracy using a model combining age, current diagnosis of hypertension, baseline MoCA scores, MDS-UPDRS III scores, and APOE status. Our study underscores the need for the earlier identification of CI in NDPD patients in our clinical practice.

6.
Food Chem Toxicol ; 175: 113725, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36925041

RESUMO

Lead (Pb) can pollute the environment and food through air, water and other means, resulting in human exposure to lead pollution, and there is no threshold level of lead toxicity, even small doses of lead will have a range of harmful effects in humans. This study demonstrates for the first time that dietary addition of soluble dietary fiber (SDF) from Prunus persica dregs reduces lead bioaccumulation in mice, and eliminates lead through feces. Compared with lead-exposed mice, SDF supplementation effectively prevented lead-induced changes in colon tissue, and increased expression of tight junction proteins (ZO-1 and occludin). We analyzed the effects of SDF on gut microbiota and metabolites by a combination of 16S rRNA high-throughput sequencing and untargeted metabolomics. The results showed that SDF altered lead-induced perturbations in the layout and structure of the gut microbiota, including increased Desulfovibrio and Alistipes abundance and decreased Bacteroidetes abundance. Meanwhile, we also provide evidence that SDF supplementation alters the levels of amino acids, bile acids, and lipids in the gut, and that these metabolites are closely associated with microbiota with good lead binding capacity. Therefore, we speculate that SDF has the potential to provide a protective effect against intestinal damage by promoting lead excretion.


Assuntos
Microbioma Gastrointestinal , Prunus persica , Humanos , Animais , Camundongos , Chumbo/toxicidade , Chumbo/metabolismo , Prunus persica/genética , Prunus persica/metabolismo , RNA Ribossômico 16S/genética , Fibras na Dieta/farmacologia
7.
ACS Nano ; 16(6): 9691-9700, 2022 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-35587990

RESUMO

Animals execute intelligent and efficient interactions with their surroundings through neural pathways, exhibiting learning, memory, and cognition. Artificial autonomous devices that generate self-optimizing feedback mimicking biological systems are essential in pursuing future intelligent robots. Here, we report an artificial neural pathway (ANP) based on a memristor synapse to emulate neuromorphic learning behaviors. In our ANP, optical stimulations are detected and converted into electrical signals through a flexible perovskite photoreceptor. The acquired electrical signals are further processed in a zeolitic imidazolate frameworks-8 (ZIF-8)-based memristor device. By controlling the growth of the ZIF-8 nanoparticles, the conductance of the memristor can be finely modulated with electrical stimulations to mimic the modulation of synaptic plasticity. The device is employed in the ANP to implement synaptic functions of learning and memory. Subsequently, the synaptic feedbacks are used to direct a robotic arm to perform responding motions. Upon repeatedly "reviewing" the optical stimulation, the ANP is able to learn, memorize, and complete the specific motions. This work provides a promising strategy toward the design of intelligent autonomous devices and bioinspired robots through memristor-based systems.


Assuntos
Sinapses , Animais , Vias Neurais , Plasticidade Neuronal , Sinapses/fisiologia
8.
Brain Sci ; 12(4)2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35448020

RESUMO

It is generally believed that eye movements are completely spared in amyotrophic lateral sclerosis (ALS). Although a series of eye movement abnormalities has been recognized in recent years, the findings are highly controversial, and bulbar disabilities should be considered in relation to eye movement abnormalities. The present study aimed to determine whether eye movement abnormalities are present in ALS and, if so, to investigate their characteristics and their association with bulbar disability in ALS patients. A total of 60 patients and 30 controls were recruited and underwent the standardized evaluations of the oculomotor system using videonystagmography. Square-wave jerks (OR: 16.20, 95% CI: 3.50−74.95, p < 0.001) and abnormal cogwheeling during smooth pursuit (OR: 14.04, 95% CI: 3.00−65.75, p = 0.001) were more frequently observed in ALS patients than in the control subjects. In subgroup analyses, square-wave jerks (OR: 26.51, 95% CI: 2.83−248.05, p = 0.004) and abnormal cogwheeling during smooth pursuit (OR: 6.56, 95% CI: 1.19−36.16, p = 0.031) were found to be more common in ALS patients with bulbar involvement (n = 44) than in those without bulbar involvement (n = 16). There were no significant differences in the investigated eye movement parameters between bulbar-onset (n = 12) and spinal-onset patients (n = 48). ALS patients showed a range of eye movement abnormalities, affecting mainly the ocular fixation and smooth pursuit systems. Our pioneering study indicates that the region of involvement could better indicate the pathophysiological essence of the abnormalities than the type of onset pattern in ALS. Eye movement abnormalities may be potential clinical markers for objectively evaluating upper brainstem or supratentorial cerebral lesion neurodegeneration in ALS.

9.
Exp Cell Res ; 415(1): 113120, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35341775

RESUMO

Glucocorticoid (GC)-induced osteoporosis (GIOP) is the most common type of secondary osteoporosis. Osteoblast apoptosis induced by GCs is now considered as a crucial factor for GIOP. Many clinical, in vivo, and in vitro studies have shown that metformin has a beneficial effect on bone metabolism and bone formation. To investigate whether metformin could be used to treat GIOP, we explored the influence of metformin on dexamethasone (Dex)-induced apoptosis of osteoblasts and its underlying mechanisms. In this study, the CCK8 assay was used to determine the optimal metformin concentration and processing time. The expression levels of target proteins were examined by Western blot and immunofluorescence; the expression levels of target genes were tested by quantitative PCR. Apoptotic cells were detected using flow cytometry. Characteristics of autophagy were observed by transmission electron microscopy. An autophagy inhibitor was administered to investigate whether autophagy decreases apoptosis. Sh-AMPK transfection and an mTOR activator were used to investigate the role of AMPK/mTOR signaling in metformin-induced autophagy. The results showed that metformin alleviated Dex-induced apoptosis of osteoblasts accompanied by increased autophagy. Treatment with the autophagy inhibitor 3-methyladenine (3-MA) attenuated the effect of metformin on apoptosis, autophagy, and the AMPK/mTOR/p70S6K signaling pathway. The anti-apoptotic effect of metformin on osteoblasts is associated with the promotion of autophagy. Furthermore, sh-AMPK transfection and the mTOR activator MHY1485 impaired metformin-mediated inhibition of osteoblast apoptosis and promotion of autophagy. The AMPK/mTOR/p70S6K signaling pathway plays a role in metformin-mediated apoptosis suppression and autophagy promotion. In conclusion, metformin can alleviate Dex-induced osteoblast apoptosis by inducing autophagy via the AMPK/mTOR/p70S6K pathway. This study highlights the potential value of metformin in the treatment of GIOP.


Assuntos
Metformina , Osteoporose , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Apoptose , Autofagia , Dexametasona/efeitos adversos , Humanos , Metformina/farmacologia , Osteoblastos/metabolismo , Osteoporose/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo
10.
Neuro Endocrinol Lett ; 42(4): 236-244, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34436844

RESUMO

OBJECTIVES: Osteoblasts play an important role in the process of osteogenesis and prevention of osteonecrosis. Dexamethasone, a type of glucocorticoids (GCs), induce apoptosis of osteoblasts and lead to the occurrence of non-traumatic osteonecrosis. This study aimed to explore the effects of different doses and duration of Dexamethasone on osteoblast apoptosis of rats in vitro. METHODS: Proliferation and apoptosis of osteoblasts after Dexamethasone treatment were detected using cell counting kit-8 (CCK-8) assay and FITC-Annexin V/PI staining. The expressions of caspase-3 and -9 in osteoblasts after Dexamethasone treatment were analyzed using western blotting and qRT-PCR. Dexamethasone remarkably inhibited proliferation and induced apoptosis of osteoblasts in a dose-and duration-dependent manner. RESULTS: As the intervention time extended, the expression of caspase-3 mRNA and caspase-9 mRNA in different Dexamethasone groups gradually increased in a duration-dependent manner. With the same time of intervention (12h, 24h, 48h), the expression of caspase-3 and -9 mRNA gradually increased in a dose-dependent manner. After treated with 5 * 10-8M, 5 * 10-7M, 5 * 10-6M and 5 * 10-5M Dexamethasone for 24 hours, the expression of cleaved caspase-3 and -9 protein increased in a dose-dependent manner. CONCLUSION: Dexamethasone can induce osteoblast apoptosis in a duration- and dose-dependent manner.

11.
Diabetes Metab Syndr Obes ; 14: 1431-1443, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33833536

RESUMO

PURPOSE: Several previous reports have highlighted the association between adiposity and risk of metabolic syndrome (MetS). Although it is necessary to identify which adiposity indices are best suited to identify MetS, no such study has been completed in diabetic patients. The aim of this study was to evaluate the ability of eight anthropometric indices to identify MetS in diabetic, middle-aged and elderly Chinese patients. PATIENTS AND METHODS: A cross-sectional study was conducted in 906 type 2 diabetic patients in Guangxi. RESULTS: The highest odds ratios for the identification of MetS were identified with CUN-BAE (OR = 28.306). The largest areas under the curve (AUCs) were observed for WHtR and BRI in men aged 40-59; CUN-BAE in men aged 60 and over; WHtR, BRI, and TyG in women aged 40-59; and BMI for women aged 60 and over. The weakest indicator for the screening of MetS in type 2 diabetes was the ABSI. CONCLUSION: The most effective anthropometric indicator for the identification of MetS varied across sex and age subgroups.

12.
Medicine (Baltimore) ; 100(13): e25303, 2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33787620

RESUMO

ABSTRACT: This study aimed to investigate the association between mean platelet volume (MPV) and metabolic syndrome (MetS) in patients with type 2 diabetes mellitus (T2DM). Data for 1240 patients with T2DM admitted to the Department of Endocrinology at the First Affiliated Hospital of Guangxi Medical University between January 1, 2017 and June 1, 2020 were collected retrospectively via electronic medical records, including demographic information, complete blood count, lipid profile, and glucose metabolism indexes. MetS was defined according to the Chinese Diabetes Society. Among the 1240 patients enrolled, 873 (70.40%) had MetS. MPV was significantly higher in patients with MetS (P < .001). For individual MetS components, MPV was significantly higher in the presence of abdominal obesity (P = .013) and hypertriglyceridemia (P = .026), but did not differ in the presence of elevated blood pressure (P = .330) or low high-density lipoprotein cholesterol (P = .790). Moreover, MPV was independently associated with MetS after adjustment for sex, smoking, alcohol drinking, white blood cell count, fasting C-peptide, and body mass index (odds ratio 1.174, 95% confidence interval 1.059-1.302). The odds ratio for MetS in the highest tertile, compared with the lowest MPV tertile, was 1.724 (95% confidence interval 1.199-2.479, P for trend = .003) after multiple adjustment. In stratified analyses, the positive correlation of MPV with MetS was significant only in patients who were older, male, or overweight, or who had poor glycemic control. In conclusion, high MPV was positively associated with the presence of MetS in patients with T2DM, particularly older, male, or overweight patients, or those with poor glycemic control.


Assuntos
Diabetes Mellitus Tipo 2/sangue , Volume Plaquetário Médio , Síndrome Metabólica/sangue , Adulto , Fatores Etários , Idoso , Contagem de Células Sanguíneas , Glicemia , Pressão Sanguínea , Índice de Massa Corporal , Fatores de Risco Cardiometabólico , China , Diabetes Mellitus Tipo 2/complicações , Feminino , Humanos , Lipídeos/sangue , Masculino , Síndrome Metabólica/etiologia , Pessoa de Meia-Idade , Sobrepeso/sangue , Sobrepeso/complicações , Estudos Retrospectivos , Fatores Sexuais
13.
Nat Commun ; 11(1): 4602, 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32929071

RESUMO

Human behaviors are extremely sophisticated, relying on the adaptive, plastic and event-driven network of sensory neurons. Such neuronal system analyzes multiple sensory cues efficiently to establish accurate depiction of the environment. Here, we develop a bimodal artificial sensory neuron to implement the sensory fusion processes. Such a bimodal artificial sensory neuron collects optic and pressure information from the photodetector and pressure sensors respectively, transmits the bimodal information through an ionic cable, and integrates them into post-synaptic currents by a synaptic transistor. The sensory neuron can be excited in multiple levels by synchronizing the two sensory cues, which enables the manipulating of skeletal myotubes and a robotic hand. Furthermore, enhanced recognition capability achieved on fused visual/haptic cues is confirmed by simulation of a multi-transparency pattern recognition task. Our biomimetic design has the potential to advance technologies in cyborg and neuromorphic systems by endowing them with supramodal perceptual capabilities.


Assuntos
Células Receptoras Sensoriais/fisiologia , Tato/fisiologia , Visão Ocular/fisiologia , Animais , Linhagem Celular , Eletrodos , Humanos , Camundongos , Movimento (Física) , Nanotubos de Carbono/química , Reconhecimento Automatizado de Padrão
14.
ACS Appl Mater Interfaces ; 11(31): 27882-27889, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31293147

RESUMO

Despite their emergence as promising materials for low-cost and efficient energy power generation technology, the instability of hybrid organic-inorganic lead-halide perovskites toward moisture and heat stress remains a serious obstacle that needs to be tackled for commercialization. Here, we show improved moisture and thermal stability through the use of cesium oleate to modify the perovskite/hole transporting material interface. Passivation using cesium oleate does not induce the formation of any low-dimensional perovskites, suggesting that the organic species only passivate the perovskite's surface and grain boundaries. As a result, enhanced hydrophobic character of the perovskite film is realized upon passivation, evidenced by a large water contact angle of 107.4° and improved stability at ambient conditions (a relative humidity of ∼70%, room temperature). Concomitantly, the proposed passivation strategy leads to an increased amount of cesium concentration within the films, resulting in beneficial enhanced thermal stability of the film at 85 °C. By maintaining the three-dimensional (3D) structure of the solar absorber while concurrently passivating the interfacial defects and vacancies, improved open-circuit voltage (Voc) and unsacrificed short-circuit current density (Jsc) were obtained from the treated devices, leading to power conversion efficiencies of more than 18%. When stored in a humid environment (a relative humidity of ∼55%), devices with cesium oleate passivation maintain 88% of their initial power conversion efficiency after 720 h, degrading two times slower than those of the control. This work offers a strategy of coating 3D perovskites with a unique combination of inorganic cations and long-chain organics to provide hydrophobicity and moisture stability to the solar absorber layer while maintaining good device performances.

15.
Adv Mater ; 31(7): e1806385, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30556251

RESUMO

As emerging efficient emitters, metal-halide perovskites offer the intriguing potential to the low-cost light emitting devices. However, semiconductors generally suffer from severe luminescence quenching due to insufficient confinement of excitons (bound electron-hole pairs). Here, Sn-triggered extrinsic self-trapping of excitons in bulk 2D perovskite crystal, PEA2 PbI4 (PEA = phenylethylammonium), is reported, where exciton self-trapping never occurs in its pure state. By creating local potential wells, isoelectronic Sn dopants initiate the localization of excitons, which would further induce the large lattice deformation around the impurities to accommodate the self-trapped excitons. With such self-trapped states, the Sn-doped perovskites generate broadband red-to-near-infrared (NIR) emission at room temperature due to strong exciton-phonon coupling, with a remarkable quantum yield increase from 0.7% to 6.0% (8.6 folds), reaching 42.3% under a 100 mW cm-2 excitation by extrapolation. The quantum yield enhancement stems from substantial higher thermal quench activation energy of self-trapped excitons than that of free excitons (120 vs 35 meV). It is further revealed that the fast exciton diffusion involves in the initial energy transfer step by transient absorption spectroscopy. This dopant-induced extrinsic exciton self-trapping approach paves the way for extending the spectral range of perovskite emitters, and may find emerging application in efficient supercontinuum sources.

16.
Int J Syst Evol Microbiol ; 67(12): 5172-5178, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29043950

RESUMO

A Gram-stain-negative, facultative anaerobic and oligotrophic, rod-shaped, and motile with single polar flagellum bacterial strain, designed M11-4T was isolated from mangrove sediment in Yunxiao Mangrove National Nature Reserve, China. Growth was observed at temperatures from 10 to 40 °C (optimum 30 °C), at salinities from 0.5 to 6 % (optimum 2-3 %), and at pH from 5 to 8 (optimum 6). Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain M11-4T shared highest sequence similarity with the genus Marinobacter(92.5-95.0 %) and represented a distinct phylogenetic lineage in the family Alteromonadaceae. The G+C content of the genomic DNA was 58.2 mol%. The dominant fatty acids were C16 : 0, C16 : 0 N-alcohol, summed feature 9 (comprising iso-C17 : 1ω9c and/or C16 : 0 10-methyl) and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c). The predominant respiratory quinone was ubiquinone-9 and the major polar lipids were diphosphatidylglycerol; phosphatidylethanolamine; phosphatidylglycerol and an unidentified aminophospholipid. According to its morphology, physiology, fatty acid composition and 16S rRNA gene sequence analysis, the strain M11-4T should be assigned as a novel species of a novel genus for which the name Mangrovitalea sediminis gen. nov., sp. nov. is proposed. The type strain of Mangrovitalea sediminis is M11-4T (=MCCC 1K03312T=JCM 32104T).


Assuntos
Alteromonadaceae/classificação , Avicennia/microbiologia , Sedimentos Geológicos/microbiologia , Filogenia , Alteromonadaceae/genética , Alteromonadaceae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
17.
ACS Appl Mater Interfaces ; 9(25): 21292-21297, 2017 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-28574243

RESUMO

Owing to improvements in film morphology, crystallization process optimization, and compositional design, the power conversion efficiency of perovskite solar cells has increased from 3.8 to 22.1% in a period of 5 years. Nearly defect-free crystalline films and slow recombination rates enable polycrystalline perovskite to boast efficiencies comparable to those of multicrystalline silicon solar cells. However, volatile low melting point components and antisolvent treatments essential for the processing of dense and smooth films often lead to surface defects that hamper charge extraction. In this study, we investigate methylammonium bromide (MABr) surface treatments on perovskite films to compensate for the loss of volatile cation during the annealing process for surface defect passivation, grain growth, and a bromide-rich top layer. This facile method did not change the phase or bandgap of perovskite films yet resulted in a significant increase in the open circuit voltages of devices. The devices with 10 mM MABr treatment show 2% improvement in absolute power conversion efficiency over the control sample.

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