Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 188
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Nano Lett ; 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38953472

RESUMO

Quasi-2D perovskites based blue light-emitting diodes (LEDs) suffer from its poor electroluminescence performance, mainly caused by the nonradiative recombination in in defect-rich low-n phases and the unbalanced hole-electron injection in the device. Here, we developed a highly efficient quasi-2D perovskite based sky-blue LEDs behaving recorded external quantum efficiency (EQE) of 21.07% by employing carbon dots (CDs) as additives in the hole transport layer (HTL). We ascribe the high EQE to the effective engineering of CDs: (1) The CDs at the interface of HTLs can suppress the formation of low-efficient n = 1 phase, resulting a high luminescence quantum yield and energy transfer efficiency of the mixed n-phase quasi-2D perovskites. (2) The CDs additives can reduce the conductivity of HTL, partially blocking the hole injection, and thus making more balanced hole-electron injection. The CDs-treated devices have excellent Spectral stability and enhanced operational stability and could be a new alternative additive in the perovskite optoelectronic devices.

2.
J Am Chem Soc ; 146(11): 7658-7667, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38452365

RESUMO

High-power phosphor-converted white light-emitting diodes (hp-WLEDs) have been widely involved in modern society as outdoor lighting sources. In these devices, due to the Joule effect, the high applied currents cause high operation temperatures (>500 K). Under these conditions, most phosphors lose their emission, an effect known as thermal quenching (TQ). Here, we introduce a zero-dimensional (0D) metal halide, Rb3InCl6:xSb3+, as a suitable anti-TQ phosphor offering robust anti-TQ behavior up to 500 K. We ascribe this behavior of the metal halide to two factors: (1) a compensation process via thermally activated energy transfer from structural defects to emissive centers and (2) an intrinsic structural rigidity of the isolated octahedra in the 0D structure. The anti-TQ phosphor-based WLEDs can stably work at a current of 2000 mA. The low synthesis cost and nontoxic composition reported here can herald a new generation of anti-TQ phosphors for hp-WLED.

3.
Nano Lett ; 23(19): 9050-9055, 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37756015

RESUMO

We report the colloidal synthesis of Bi-doped Cs2AgxNa1-xInCl6 double perovskite nanoplatelets (NPLs) exhibiting a near-unity photoluminescence quantum yield (PLQY), a record emission efficiency for nanoscale lead-free metal halides. A combination of optical spectroscopies revealed that nonradiative decay processes in the NPL were suppressed, indicating a well-passivated surface. By comparison, nanocubes with the same composition and surface ligands as the NPLs had a PLQY of only 40%. According to our calculations, the type of trap states arising from the presence of surface defects depends on their specific location: defects located on the facets of nanocubes generate only shallow traps, while those at the edges result in deep traps. In NPLs, due to their extended basal facets, most of the surface defects are facet defects. This so-called facet-defect tolerant behavior of double perovskites explains the more efficient optical emission of NPLs compared to that of nanocubes.

4.
J Gene Med ; 25(3): e3468, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36518003

RESUMO

BACKGROUND: It is difficult to distinguish between arrhythmogenic cardiomyopathy (ACM) and dilated cardiomyopathy (DCM) because of their similar clinical manifestations. This study aimed to develop a novel diagnostic algorithm for distinguishing ACM from DCM. METHODS: Two public datasets containing human ACM and DCM myocardial samples were used. Consensus clustering, non-negative matrix factorization and principal component analysis were applied. Weighted gene co-expression network analysis and machine learning methods, including random forest and the least absolute shrinkage and selection operator, were used to identify candidate genes. Receiver operating characteristic curves and nomograms were performed to estimate diagnostic efficacy, and Spearman's correlation analysis was used to assess the correlation between candidate genes and cardiac function indices. RESULTS: Both ACM and DCM showed highly similar gene expression patterns in the clustering analyses. Hub gene modules associated with cardiomyopathy were obtained using weighted gene co-expression network analysis. Thirteen candidate genes were selected using machine learning algorithms, and their combination showed a high diagnostic value (area under the ROC curve = 0.86) for distinguishing ACM from DCM. In addition, TATA-box binding protein associated factor 15 showed a negative correlation with cardiac index (R = -0.54, p = 0.0054) and left ventricular ejection fraction (R = -0.48, p = 0.0015). CONCLUSIONS: Our study revealed an effective diagnostic model with key gene signatures, which indicates a potential tool to differentiate between ACM and DCM in clinical practice. In addition, we identified several genes that are highly related to cardiac function, which may contribute to our understanding of ACM and DCM.


Assuntos
Cardiomiopatias , Cardiomiopatia Dilatada , Humanos , Cardiomiopatia Dilatada/genética , Volume Sistólico , Função Ventricular Esquerda , Perfilação da Expressão Gênica , Algoritmos , Aprendizado de Máquina
5.
Front Zool ; 20(1): 30, 2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-37653456

RESUMO

BACKGROUND: The classic optimal foraging theory (OFT) predicts animals' food patch use assuming that individuals in a population use the same strategy while foraging. However, due to the existence of animal personality, i.e. repeatable inter-individual differences and intra-individual consistency in behaviours over time and/or across contexts, individuals often exhibit different behavioural strategies, challenging the basic assumptions of the OFT. Here, we tested whether personality traits (boldness and exploration in open arena) of Japanese quail (Coturnix japonica, 38 females and 34 males) influenced their patch use in two foraging experiments with different inter-patch distances (i.e. 2 m in Experiment 1 and 3 m in Experiment 2). RESULTS: The total feeding time and food intake of individuals did not differ between Experiment 1 and 2, but in both experiments, proactive (i.e. bolder and more explorative) individuals had longer feeding time and higher food intake than reactive individuals. In Experiment 1, proactive quails changed patches more frequently and had shorter mean patch residence time than reactive individuals, while the effects were not significant in Experiment 2. The quails reduced patch residence time along with feeding, and this trend was weakened in Experiment 2 which had longer inter-patch distance. CONCLUSIONS: The above results suggest that personality traits affect animals' patch use, while the effects might be weakened with longer inter-patch distance. Our study highlights that animal personality should be considered when investigating animals' foraging behaviours because individuals may not adopt the same strategy as previously assumed. Furthermore, the interaction between personality traits and inter-patch distances, which is related to movement cost and capacity of information gathering, should also be considered.

6.
Front Zool ; 20(1): 1, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36604706

RESUMO

BACKGROUND: The high-altitude-adapted frog Rana kukunoris, occurring on the Tibetan plateau, is an excellent model to study life history evolution and adaptation to harsh high-altitude environments. However, genomic resources for this species are still underdeveloped constraining attempts to investigate the underpinnings of adaptation. RESULTS: The R. kukunoris genome was assembled to a size of 4.83 Gb and the contig N50 was 1.80 Mb. The 6555 contigs were clustered and ordered into 12 pseudo-chromosomes covering ~ 93.07% of the assembled genome. In total, 32,304 genes were functionally annotated. Synteny analysis between the genomes of R. kukunoris and a low latitude species Rana temporaria showed a high degree of chromosome level synteny with one fusion event between chr11 and chr13 forming pseudo-chromosome 11 in R. kukunoris. Characterization of features of the R. kukunoris genome identified that 61.5% consisted of transposable elements and expansions of gene families related to cell nucleus structure and taste sense were identified. Ninety-five single-copy orthologous genes were identified as being under positive selection and had functions associated with the positive regulation of proteins in the catabolic process and negative regulation of developmental growth. These gene family expansions and positively selected genes indicate regions for further interrogation to understand adaptation to high altitude. CONCLUSIONS: Here, we reported a high-quality chromosome-level genome assembly of a high-altitude amphibian species using a combination of Illumina, PacBio and Hi-C sequencing technologies. This genome assembly provides a valuable resource for subsequent research on R. kukunoris genomics and amphibian genome evolution in general.

7.
Artigo em Inglês | MEDLINE | ID: mdl-37155004

RESUMO

BACKGROUND: Prolonged use of anti-arrhythmic drugs (AAD) beyond the post-ablation blanking period to maintain sinus rhythm has been adopted in clinical practice but without sufficient evidence. Dronedarone is an AAD valid for maintaining sinus rhythm with fewer side effects than other AAD for long-term use. OBJECTIVE: We sought to investigate the effect of prolonged use of dronedarone on the recurrence of non-paroxysmal AF patients beyond 3 months within the first year after ablation. METHODS: Non-paroxysmal AF patients will receive dronedarone for 3 months after radiofrequency ablation. Patients without drug side effects and atrial tachyarrhythmia (AT) recurrence will then be randomly divided into dronedarone and placebo groups and followed up until 1 year after ablation. The primary endpoint is the cumulative nonrecurrence rate post 3 months to 1 year after ablation. Patients will receive 7-day Holter monitoring (ECG patch) at 6, 9, and 12 months after ablation to evaluate AT recurrence. Secondary endpoints include dronedarone withdrawal due to side effects or intolerance of AT recurrence, time to the first recurrence, repeat ablation, electrical cardioversion, unscheduled emergency room visit, or re-hospitalization. CONCLUSION: This trial will evaluate whether prolonged use of dronedarone effectively reduces the recurrence rate after ablation in non-paroxysmal AF patients. The result of this trial will provide evidence for optimizing post-ablation anti-arrhythmic therapy. TRIAL REGISTRATION: ClinicalTrials.gov ; NCT05655468, 19-December-2022.

8.
Sensors (Basel) ; 23(14)2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37514699

RESUMO

Interfacial zones straddling terrestrial and marine realms, colloquially known as mudflats, epitomize a dynamic nexus between these environments and are fundamental to the coastal ecosystem. The investigation of these regions is paramount for facilitating infrastructural developments including ports, wharfs, cross-sea bridges, and the strategic utilization of freshwater resources sequestered from mainland islands amid ongoing economic progress. Terrestrial realms conventionally employ electromagnetic techniques as efficacious modalities to delineate subterranean geological information, encompassing structural details and water-bearing strata. However, the peculiar topographic and geological nuances of mudflat regions pose substantial challenges for the efficacious application of electromagnetic methodologies. The present paper endeavors to address these challenges by suggesting innovative modifications to the existing instrumentation and evolving novel data acquisition techniques specifically tailored for electromagnetic exploration within mudflat environments. This paper delves into the electrical characteristics of water-bearing layers within mudflats, and ascertains details pertaining to the subterranean structure and the spatial distribution of fresh and saline water resources, through the holistic interpretation of a multitude of profiles.

9.
J Am Chem Soc ; 144(11): 5059-5066, 2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35258285

RESUMO

CsPbBr3 nanoclusters have been synthesized by several groups and mostly employed as single-source precursors for the synthesis of anisotropic perovskite nanostructures or perovskite-based heterostructures. Yet, a detailed characterization of such clusters is still lacking due to their high instability. In this work, we were able to stabilize CsPbBr3 nanoclusters by carefully selecting ad hoc ligands (benzoic acid together with oleylamine) to passivate their surface. The clusters have a narrow absorption peak at 400 nm, a band-edge emission peaked at 410 nm at room temperature, and their composition is identified as CsPbBr2.3. Synchrotron X-ray pair distribution function measurements indicate that the clusters exhibit a disk-like shape with a thickness smaller than 2 nm and a diameter of 13 nm, and their crystal structure is a highly distorted orthorhombic CsPbBr3. Based on small- and wide-angle X-ray scattering analyses, the clusters tend to form a two-dimensional (2D) hexagonal packing with a short-range order and a lamellar packing with a long-range order.

10.
J Cardiovasc Electrophysiol ; 33(8): 1769-1778, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35634859

RESUMO

INTRODUCTION: Conventional unipolar catheter ablation (UA) is generally effective for the treatment of outflow tract ventricular arrhythmias (OT-VAs). However, deep foci refractory to UA remains a clinical challenge. The present study evaluated the efficacy and safety of bipolar ablation (BA) in the treatment of OT-VAs refractory to UA. METHODS: A total of 1022 consecutive patients with antiarrhythmic drugs resistant OT-VAs were screened for inclusion in this study, from 1643 VAs cases who underwent catheter ablation in two centers from October 2014 to May 2019. BA was performed after failed sequential UA. The pair of catheters used for BA was positioned on opposing surfaces of the earliest activation (EA) sites or on adjacent anatomical structures. RESULTS: Twelve patients (seven males, mean age 33.3 ± 16.2 years) who met the inclusion criteria were recruited: one patient suffered sustained monomorphic ventricular tachycardia (VT), six patients had frequent premature ventricular contractions (PVCs), and nonsustained VT (NSVT), and five patients had PVCs only. The 24-hPVC/NSVT burden was 36.9 ± 21.7%. The mean distance between two ablation catheters during BA was 11.1 ± 4.3 mm (range 6.5-23.9 mm). The "rS" morphology of the unipolar electrogram was recorded simultaneously in both EA regions in seven cases (58.3%). Acute eradication of VAs was obtained in 10 (83.3%) cases. At a median follow-up of 58 months, 10 patients (83.3%) remained free from VAs. CONCLUSION: BA was highly effective and safe for the treatment of OT-VAs refractory to UA.


Assuntos
Ablação por Cateter , Taquicardia Ventricular , Complexos Ventriculares Prematuros , Adolescente , Adulto , Ablação por Cateter/efeitos adversos , Eletrocardiografia , Humanos , Masculino , Pessoa de Meia-Idade , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/cirurgia , Resultado do Tratamento , Complexos Ventriculares Prematuros/diagnóstico , Complexos Ventriculares Prematuros/etiologia , Complexos Ventriculares Prematuros/cirurgia , Adulto Jovem
11.
Front Zool ; 19(1): 5, 2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35062965

RESUMO

BACKGROUND: Despite its important implications in behavioural and evolutionary ecology, male mate choice has been poorly studied, and the relative contribution of personality and morphological traits remains largely unknown. We used standard two-choice mating trials to explore whether two personality traits (i.e., shyness and activity) and/or body size of both sexes affect mate choice in male mosquitofish Gambusia affinis. In the first set of trials involving 40 males, we tested whether males would prefer larger females and whether the preference would be affected by males' body length and personality traits, and females' activity level. In the second set of trials (using another 40 males), we tested whether males would prefer more active females and whether the preference would be affected by males' body length and personality traits. RESULTS: Both shyness and activity in males were significantly repeatable and constituted a behavioural syndrome. No overall directional preference for large (or small) females with the same activity levels was detected because larger males preferred larger females and smaller males chose smaller females. Males' strength of preference for larger females was also positively correlated with the activity level of larger females but negatively with the activity level of smaller females. Males spent more time associating with active females regardless of their body lengths, indicating males' selection was more influenced by female activity level than body size. Males' preference for inactive females was enhanced when females became active. There was no convincing evidence for the effect of males' personality traits or body length on their preferences for females' activity level. CONCLUSIONS: Our study supports the importance of body size in male mate choice but highlights that personality traits may outweigh body size preferences when males choose mating partners.

12.
BMC Cardiovasc Disord ; 22(1): 231, 2022 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-35590247

RESUMO

BACKGROUND: Left atrial (LA) size is often used as a surrogate marker of LA function in clinical practice, with larger atrial thought to represent a "dysfunctioning" atrium, since there is no accepted 'gold' standard to evaluate LA function. The exact relationship between LA size and phasic function, and whether LA dysfunction occur before LA enlargement (LAE) may be of clinical interest while have not been fully studied. Two-dimensional speckle-tracking echocardiography (2D STE) was showed a promising method in measuring LA physical deformation. MATERIALS AND METHODS: A community cohort of 715 subjects at cardiovascular disease high risk accepted comprehensive echocardiography. LA longitudinal phasic strain Sa (absolute peak strain during atrial contraction), Se (peak strain at early diastole) and Stot (total atrial strain = Sa + Se), representing contractile, conduit, and reservoir function respectively, were measured using off-line 2D STE software in apical 4 chamber view, and data were compared among groups at different LA size and between subgroups in normal LA size with and without hypertension (HT). RESULTS: With LAE (from normal size, mild, moderate to severe LAE), the Stot (21.74 ± 5.97, 20.75 ± 4.99, 20.49 ± 5.27, 17.75 ± 4.71, respectively, ANOVA P = 0.003) and Sa (11.84 ± 3.92, 11.00 ± 3.29, 10.11 ± 2.57, 8.55 ± 2.88, respectively, ANOVA P < 0.001) reduced while Se had no change. Stot of Severe LAE group was significantly lower than that of Normal LA size group (P = 0.002). Sa of the three LAE groups were all significantly lower than that of Normal LA size group (P = 0.024, P = 0.002, P < 0.001, respectively). In normal sized LA subgroups, Stot (21.35 ± 5.91 vs. 23.01 ± 6.02, P = 0.008) and Se (9.51 ± 4.41 vs. 11.17 ± 4.89, P < 0.001) reduced in subjects with HT comparing with those without. CONCLUSION: LA phasic function remodeling occurs before LAE and continues with LAE, with reservoir, conduit and contractile function being affected unparalleled.


Assuntos
Remodelamento Atrial , Hipertensão , Função do Átrio Esquerdo , Ecocardiografia/métodos , Átrios do Coração/diagnóstico por imagem , Humanos
13.
BMC Cardiovasc Disord ; 22(1): 579, 2022 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-36587201

RESUMO

BACKGROUND: Left ventricular (LV) geometry is closely associated with cardiovascular disease; however, few studies have evaluated the relationship between basal septal hypertrophy (BSH) and LV geometry. In this study, we examined the relationship between BSH and LV geometry in a Beijing community population. METHODS: The clinical and echocardiographic data of 1032 participants from a community in Beijing were analyzed. BSH was defined as a basal interventricular septal thickness ≥ 14 mm and a basal septal thickness/mid-septal thickness ≥ 1.3. On the basis of their echocardiographic characteristics, patients were described as having a normal geometry, concentric remodeling, concentric hypertrophy, or eccentric hypertrophy. Multivariable logistic regression was used to analyze the relationship between BSH, LV mass index (LVMI), and relative wall thickness (RWT). RESULTS: The prevalence of BSH was 7.4% (95% confidence interval [CI] 5.8-9.0%). Basal and middle interventricular septal thickness, LV posterior wall thickness, and RWT were greater, while LVMI and LV end-diastolic dimension were lower in the BSH group than in the non-BSH group (p < 0.05). The BSH group accounted for the highest proportion of patients with concentric remodeling. A multivariable regression analysis showed that BSH increased by 3.99-times (odds ratio [OR] 3.99, 95% CI 2.05-7.78, p < 0.01) when RWT was > 0.42, but not when LVMI increased (OR 0.16, 95% CI 0.02-1.19, p = 0.07). There were no interactions between BSH and age, body mass index, sex, diabetes mellitus, coronary heart disease, stroke, and smoking in relation to an RWT > 0.42. CONCLUSION: BSH was independently associated with an RWT > 0.42.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/epidemiologia , Hipertrofia Ventricular Esquerda/complicações , Ecocardiografia , Ventrículos do Coração/diagnóstico por imagem , Remodelação Ventricular
14.
Cardiovasc Ultrasound ; 20(1): 27, 2022 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-36434713

RESUMO

BACKGROUND: The left atrium (LA) is closely related to left ventricular diastolic function. Two-dimensional speckle tracking strain and strain rate (SR) imaging has been applied in the study of LA function. We intended to explore the relationship between global LA deformation parameters and plasma NTproBNP levels in asymptomatic community residents with normal ejection fraction and normal LA volume. METHODS: A cross-sectional sample of Beijing residents underwent comprehensive Doppler echocardiography and medical record review in 2009. Global LA longitudinal strain and SR indexes were obtained in the apical four-chamber view. LA stiffness index (LASI) was calculated as the ratio of early diastolic velocity of transmitral flow/early diastolic mitral annular motion velocity (E/E') to LA reservoir strain. RESULTS: A total of 620 individuals (mean age = 65.8 years, left ventricular ejection fraction = 70.8%, LA volume index = 17.9 ml/m2) were investigated in our study. 117 individuals had increased plasma NTproBNP (≥ 125 pg/ml). LA reservoir and contractile function by LA strain and SR indexes were significantly reduced in the abnormal NTproBNP group compared with the normal NTproBNP group. Multiple regression analysis indicated that LA contractile strain was a negative predictor of plasma NTproBNP in addition to indexed LA volume and E/E'. LASI was higher in the abnormal NTproBNP group and was significantly correlated with NTproBNP (r = 0.342, P < 0.001). The area under ROC analysis for LASI in predicting elevated plasma NTproBNP was 0.690, similar with LA contractile strain, E/E' and LAVI. The cut-off value of LASI was 0.612. CONCLUSIONS: LA reservoir and contractile functions demonstrated by LA strain and SR were significantly impaired in the community-based population with increased plasma NTproBNP levels. LA contractile strain adds incremental information in predicting abnormal NTproBNP levels. As a single index, LASI showed similar diagnostic value with LAVI and E/E' in predicting abnormal NTproBNP.


Assuntos
Ecocardiografia , Função Ventricular Esquerda , Humanos , Idoso , Volume Sistólico , Estudos Transversais , Ecocardiografia/métodos , Átrios do Coração/diagnóstico por imagem
15.
BMC Cardiovasc Disord ; 21(1): 262, 2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-34049490

RESUMO

BACKGROUND: We examined the relationship between epicardial fat thickness (EFT) measured by echocardiography and left ventricular diastolic function parameters in a Beijing community population. METHODS: We included 1004 participants in this study. Echocardiographic parameters including E and A peak velocity, the early diastolic velocities (e') of the septal and lateral mitral annulus using tissue doppler imaging, E/e', and EFT were measured. EFT1 was measured perpendicularly on the right ventricular free wall at end diastole in the extension line of the aortic root. EFT2 was the maximum thickness measured perpendicularly on the right ventricular free wall at end diastole. Multivariable linear regression was used to analyze the relationship between EFT and the mean e' and E/e'. RESULTS: The mean age of the participants was 63.91 ± 9.02 years, and 51.4% were men. EFT1 and EFT2 were negatively correlated with lateral e', septal e', and mean e' (p < 0.05), and the correlation coefficient for EFT1 and EFT2 and mean e' was - 0.138 and - 0.180, respectively. EFT1 and EFT2 were positively correlated with lateral E/e', septal E/e', and mean E/e' (p < 0.05), and the correlation coefficient for EFT1 and EFT2 and mean e' was 0.100 and 0.090, respectively. Multivariable egression analysis showed that EFT2 was independently and negatively associated with e' mean (ß = - 0.078 [95% confidence interval = - 0.143, - 0.012, p = 0.020]). There were no interactions between EFT2 and any covariates, including age or heart groups, sex, BMI, or presence of hypertension, diabetes, or coronary heart disease, in relation to left ventricular diastolic dysfunction. CONCLUSIONS: EFT2 was negatively and independently associated with e' mean, which suggests that more attention to this type of adipose fat is required for cardiovascular disease therapy.


Assuntos
Tecido Adiposo/diagnóstico por imagem , Adiposidade , Ecocardiografia Doppler , Pericárdio/diagnóstico por imagem , Disfunção Ventricular Esquerda/diagnóstico por imagem , Função Ventricular Esquerda , Tecido Adiposo/fisiopatologia , Adulto , Idoso , Pequim/epidemiologia , Diástole , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pericárdio/fisiopatologia , Valor Preditivo dos Testes , Prevalência , Fatores de Risco , Disfunção Ventricular Esquerda/epidemiologia , Disfunção Ventricular Esquerda/fisiopatologia
16.
Nano Lett ; 20(12): 8847-8853, 2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-33201718

RESUMO

We employed oleylphosphonic acid (OLPA) for the synthesis of CsPbBr3 nanocrystals (NCs). Compared to phosphonic acids with linear alkyl chains, OLPA features a higher solubility in apolar solvents, allowing us to work at lower synthesis temperatures (100 °C), which in turn offer a good control over the NCs size. This can be reduced down to 5.0 nm, giving access to the strong quantum confinement regime. OLPA-based NCs form stable colloidal solutions at very low concentrations (∼1 nM), even when exposed to air. Such stability stems from the high solubility of OLPA in apolar solvents, which enables these molecules to reversibly bind/unbind to/from the NCs, preventing the NCs aggregation/precipitation. Small NCs feature efficient, blue-shifted emission and an ultraslow emission kinetics at cryogenic temperature, in striking difference to the fast decay of larger particles, suggesting that size-related exciton structure and/or trapping-detrapping dynamics determine the thermal equilibrium between coexisting radiative processes.

17.
BMC Evol Biol ; 19(1): 1, 2019 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-30606099

RESUMO

BACKGROUND: Climate oscillation may have a profound effect on species distributions, gene flow patterns and population demography. In response to environmental change, those species restricted to montane habitats experienced expansions and contractions along elevation gradients, which can drive differentiation among sky islands. RESULTS: The Shangcheng stout salamander (Pachyhynobius shangchengensis) is a cool stream amphibian restricted to high-elevation areas in the Dabie Mountains, East China. In the present study, we used mtDNA genes (Cyt b and ND2) of 193 individuals and 12 nuclear microsatellite loci genotyped on 370 individuals, representing 6 populations (JTX, KHJ, MW, TTZ, BYM and KJY) across the taxon's distribution area, to investigate their genetic variation and evolutionary history of P. shangchengensis. Most populations showed unusually high levels of genetic diversity. Phylogenetic analyses revealed five monophyletic clades with divergence times ranging from 3.96 to 1.4 Mya. Accordingly, significant genetic differentiation was present between these populations. Bayesian skyline plot analyses provided that all populations underwent long-term population expansions since the last inter-glacial (0.13 Mya ~ 0.12 Mya). Msvar analyses found recent signals of population decline for two northern populations (JTX and KHJ) reflecting a strong bottleneck (approximately 15-fold decrease) during the mid-Holocene (about 6000 years ago). Ecological niche modelling has shown a discontinuity in suitable habitats for P. shangchengensis under different historical climatic conditions. CONCLUSIONS: Our results suggest that the niche conservatism of P. shangchengensis and sky island effects may have led to long-term isolation between populations. In sky island refuges, the mid-latitude Dabie Mountains have provided a long-term stable environment for P. shangchengensis, which has led to the accumulation of genetic diversity and has promoted genetic divergence.


Assuntos
Variação Genética , Ilhas , Filogenia , Rios , Urodelos/classificação , Urodelos/genética , Animais , China , Análise por Conglomerados , DNA Mitocondrial/genética , Demografia , Ecossistema , Ásia Oriental , Genótipo , Repetições de Microssatélites/genética , Filogeografia
18.
Mol Phylogenet Evol ; 137: 138-145, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31085325

RESUMO

The lack of distinct morphological features of cryptic species is a hard problem for taxonomy, especially when the taxa are closely related with considerable amounts of ancestral polymorphism. Lately, intensive coalescent-based analyses involving multiple loci have become the preferred method to assess the extent of genetic distinctiveness in otherwise phenotypically similar populations. Previously, phylogenetic studies on Pachyhynobius shangchengensis uncovered five extremely deeply divergent clades, which suggested that this species may be a cryptic species complex. In this study, we used the complete mitochondrial genome data and samples from the entire range of stout salamander (Pachyhynobius), as well as publicly available mitochondrial genomes to assess species boundaries within this genus using a suite of diverse methodologies (e.g. general mixed Yule coalescent model, Automatic Barcode Gap Discovery). The phylogenetic relationships recovered two major groups within P. shangchengensis, with one group formed by four of the six extant populations and corresponding to the central and eastern range of the Dabie mountains, while the other group encompassed two other lineages in the north west of the Dabie mountain range. The species delimitation comparison within Pachyhynobius supported the presence of recognized species within the genus, and consensus was observed across methods for the existence of up to five cryptic species within what has been traditionally considered to be P. shangchengensis. While this implies the existence of four taxa in addition to the described P. shangchengensis species, morphological data and life history information are further required to contribute to the species definition. The observed pattern of genetic variation is likely the outcome of a discontinuous habitat combined with niche conservatism, which produced the sky-island effect observed in Pachyhynobius, and which led to formation of a hidden species diversity in this genus.


Assuntos
Biodiversidade , Genoma Mitocondrial , Urodelos/genética , Animais , China , Código de Barras de DNA Taxonômico , Geografia , Filogenia , Especificidade da Espécie
19.
Anesth Analg ; 129(3): 651-658, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31425203

RESUMO

BACKGROUND: Diastolic dysfunction is common and may increase the risk of cardiovascular complications. This study investigated the hypothesis that, in patients with isolated left ventricular diastolic dysfunction, higher grade diastolic dysfunction was associated with greater risk of major adverse cardiovascular events (MACEs) after surgery. METHODS: This was a retrospective cohort study. Data of adult patients with isolated echocardiographic diastolic dysfunction (ejection fraction, ≥50%) who underwent noncardiac surgery from January 1, 2015 to December 31, 2015 were collected. The primary end point was the occurrence of postoperative MACEs during hospital stay, which included acute myocardial infarction, congestive heart failure, stroke, nonfatal cardiac arrest, and cardiac death. The association between the grade of diastolic dysfunction and the occurrence of MACEs was assessed with a multivariable logistic model. RESULTS: A total of 2976 patients were included in the final analysis. Of these, 297 (10.0%) developed MACEs after surgery. After correction for confounding factors, grade 3 diastolic dysfunction was associated with higher risk of postoperative MACEs (odds ratio, 1.71; 95% confidence interval, 1.28-2.27; P < .001) when compared with grades 1 and 2. Patients with grade 3 diastolic dysfunction developed more non-MACE complications when compared with grades 1 and 2 (uncorrected odds ratio, 1.44; 95% confidence interval, 1.07-1.95; P = .017). CONCLUSIONS: In patients with isolated diastolic dysfunction undergoing noncardiac surgery, 10.0% develop MACEs during hospital stay after surgery; grade 3 diastolic dysfunction is associated with greater risk of MACEs.


Assuntos
Ecocardiografia/tendências , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/etiologia , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento
20.
J Environ Manage ; 249: 109251, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31401449

RESUMO

Quantifying the relationship between hydrological regime and habitat availability is the first step to predict potential impacts of water engineering projects on waterbirds, particularly in periodically flooded wetlands. The proposed Yangtze-to-Huaihe Water Diversion Project (YHWD) cuts through Caizi Lake, which is of international importance for wintering waterbirds. In order to explore the potential impacts of the project on habitat availability for the wintering waterbirds, we first built linear models to fit relationships between land cover patterns and water level dynamics in the lake, and then used generalized linear mixed models to test effects of habitat variables (water area, grassland area and mudflat area) on bird abundances of different functional groups. The avian habitat use differed among guilds, and was correlated with the land cover pattern, which was strongly dependent on seasonal water level fluctuations. Following water recession in autumn, the exposure of riparian habitats was more prominent in the eastern part of the lake, where the channel of the proposed YHWD project is located. This part of the lake is also where we located most of the important bird areas. Compared to the current situation, 54.3% of the grassland and 60.5% of the mudflats are predicted to be lost during winter due to the projected water level rise, resulting in reduced habitat availability for grass foragers, invertebrate eaters and tuber feeders. In order to mitigate potential impacts of the YHWD project, we suggest habitat compensations by construction of artificial habitats, and maintenance of water level regime at the whole lake by restoring similarity in water level fluctuations between Xizi Lake and Caizi Lake.


Assuntos
Lagos , Água , Animais , Conservação dos Recursos Naturais , Ecossistema , Estações do Ano
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA