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1.
Nano Lett ; 23(6): 2287-2294, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36898060

##### RESUMO

Strong coupling between light and mechanical strain forms the foundation for next-generation optical micro- and nano-electromechanical systems. Such optomechanical responses in two-dimensional materials present novel types of functionalities arising from the weak van der Waals bond between atomic layers. Here, by using structure-sensitive megaelectronvolt ultrafast electron diffraction, we report the experimental observation of optically driven ultrafast in-plane strain in the layered group IV monochalcogenide germanium sulfide (GeS). Surprisingly, the photoinduced structural deformation exhibits strain amplitudes of order 0.1% with a 10 ps fast response time and a significant in-plane anisotropy between zigzag and armchair crystallographic directions. Rather than arising due to heating, experimental and theoretical investigations suggest deformation potentials caused by electronic density redistribution and converse piezoelectric effects generated by photoinduced electric fields are the dominant contributors to the observed dynamic anisotropic strains. Our observations define new avenues for ultrafast optomechanical control and strain engineering within functional devices.

2.
Heart Lung ; 59: 109-116, 2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36801545

##### RESUMO

BACKGROUND: Many clinical studies have shown that sodium-glucose cotransporter 2 inhibitors (SGLT2i) reduce cardiovascular risks, such as heart failure, myocardial infarction and cardiovascular death. OBJECTIVE: To investigate the use of SGLT2i for the prevention of primary and secondary cardiovascular outcomes. METHODS: Pubmed, Embase and Cochrane libraries databases were searched and meta-analysis was performed using Revman 5.4. RESULTS: Eleven studies with a total of 34,058 cases were analyzed. SGLT2i significantly reduced major adverse cardiovascular events (MACE) in patients with prior myocardial infarction (MI) (OR 0.83, 95% CI 0.73-0.94, p = 0.004), no prior MI (OR 0. 82, 95% CI 0.74-0.90, p<0.0001), prior coronary atherosclerotic disease (CAD) (OR 0.82, 95% CI 0.73-0.93, p = 0.001) and no prior CAD (OR 0.82, 95% CI 0.76-0.91, p = 0.0002) compared with placebo. In addition, SGLT2i significantly reduced hospitalization due to heart failure (HF) in patients with prior MI (OR 0.69, 95% CI 0.55-0.87, p = 0.001), no prior MI (OR 0.63, 95% CI 0.55-0. 72, p<0.00001), prior CAD (OR 0.65, 95% CI 0.53-0.79, p<0.0001) and no prior CAD (OR 0.65, 95% CI 0.56-0.75, p<0.00001) compared with placebo. SGLT2i reduced cardiovascular mortality and all-cause mortality events. MI (OR 0.79, 95% CI 0.70-0.88, p<0.0001), renal damage (OR 0.73, 95% CI 0.58-0.91, p = 0.004), all-cause hospitalization (OR 0.89, 95% CI 0.83-0.96, p = 0.002), systolic and diastolic blood pressure were all significantly reduced in patients receiving SGLT2i. CONCLUSION: SGLT2i was effective in prevention of primary and secondary cardiovascular outcomes.

3.
Mar Pollut Bull ; 186: 114424, 2022 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-36470098

##### RESUMO

Surface sediments and sediment core had been collected from Erhai Lake, Southwest China to study the concentrations, toxicity risks, and sources of polycyclic aromatic hydrocarbons (PAHs). The average concentrations of Σ16PAHs, seven carcinogenic PAHs (carPAHs), and carcinogenic toxic equivalents (TEQcar) in the surface sediments and sediment core were 1634.50 ± 488.56 ng g-1 and 436.72 ± 128.17 ng g-1, 67.18-293.65 ng g-1 and 91.07-265.90 ng g-1, and 34.89 ± 13.17 ng g-1 and 36.99 ± 7.52 ng g-1, respectively. The Σ16PAHs and carPAHs concentrations in surface sediments were higher in the southern lake. The Σ16PAHs and TEQcar in the sediment core peaked in the 2010s and 1980s. The spatiotemporal variations in TEQcar and carPAHs were similar. Positive matrix factorization revealed that traffic emissions contributed 35.71 % of the TEQcar, whereas coal and biomass combustion contributed 12.89 % in the surface sediments. The contribution of gasoline and fossil fuel to TEQcar significantly increased from 19.2 % (1890s) to 66.5 % (1990s), that of benz[a]pyrene (coal combustion) decreased, and those of benz[b]fluoranthene and indeno[1,2,3-cd]pyrene (petroleum combustion and traffic emissions) increased from 1.92 % to 3.93 % and from 1.54 % to 2.52 % in the sediment cores, respectively, owing to changes in energy consumption.

4.
Nanotechnology ; 34(7)2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36332230

##### RESUMO

Hierarchical domain structures associated with oxygen octahedra tilting patterns were observed in lead-free (Bi1/2Na1/2)TiO3ceramics using aberration-corrected high-resolution transmission electron microscopy (HRTEM). Three types of domains are induced by distinct mechanisms: the 'orientation-domain' is induced at micrometer scale formed by different tilting orientations of the oxygen octahedra, the 'meso-chemical-domain' occurs at a few tens of nanometer scale by chemical composition variation on the A-site in the ABO3perovskite structure, and the 'nano-cluster-region' runs across several unit-cells with apparent A-site cation segregation with oxygen vacancies clustering around Na cations. Based on HRTEM amplitude contrast imaging (ACI), the correlation between the oxygen octahedral tilting pattern and compositional non-stoichiometry was established. The role of the hierarchical domain structure associated with the tilting patterns of the oxygen octahedra on the ferroelectric behavior of (Bi1/2Na1/2)TiO3is also discussed.

5.
Adv Mater ; : e2206997, 2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36440651

##### RESUMO

One central challenge in understanding phonon thermal transport is a lack of experimental tools to investigate frequency-resolved phonon transport. Although recent advances in computation lead to frequency-resolved information, it is hindered by unknown defects in bulk regions and at interfaces. Here, a framework that can uncover microscopic phonon transport information in heterostructures is presented, integrating state-of-the-art ultrafast electron diffraction (UED) with advanced scientific machine learning (SciML). Taking advantage of the dual temporal and reciprocal-space resolution in UED, and the ability of SciML to solve inverse problems involving O ( 10 3 ) $\mathcal{O}({10^3})$ coupled Boltzmann transport equations, the frequency-dependent interfacial transmittance and frequency-dependent relaxation times of the heterostructure from the diffraction patterns are reliably recovered. The framework is applied to experimental Au/Si UED data, and a transport pattern beyond the diffuse mismatch model is revealed, which further enables a direct reconstruction of real-space, real-time, frequency-resolved phonon dynamics across the interface. The work provides a new pathway to probe interfacial phonon transport mechanisms with unprecedented details.

6.
Nat Commun ; 13(1): 3251, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-35668085

##### RESUMO

Conventional phase diagram generation involves experimentation to provide an initial estimate of the set of thermodynamically accessible phases and their boundaries, followed by use of phenomenological models to interpolate between the available experimental data points and extrapolate to experimentally inaccessible regions. Such an approach, combined with high throughput first-principles calculations and data-mining techniques, has led to exhaustive thermodynamic databases (e.g. compatible with the CALPHAD method), albeit focused on the reduced set of phases observed at distinct thermodynamic equilibria. In contrast, materials during their synthesis, operation, or processing, may not reach their thermodynamic equilibrium state but, instead, remain trapped in a local (metastable) free energy minimum, which may exhibit desirable properties. Here, we introduce an automated workflow that integrates first-principles physics and atomistic simulations with machine learning (ML), and high-performance computing to allow rapid exploration of the metastable phases to construct "metastable" phase diagrams for materials far-from-equilibrium. Using carbon as a prototypical system, we demonstrate automated metastable phase diagram construction to map hundreds of metastable states ranging from near equilibrium to far-from-equilibrium (400 meV/atom). We incorporate the free energy calculations into a neural-network-based learning of the equations of state that allows for efficient construction of metastable phase diagrams. We use the metastable phase diagram and identify domains of relative stability and synthesizability of metastable materials. High temperature high pressure experiments using a diamond anvil cell on graphite sample coupled with high-resolution transmission electron microscopy (HRTEM) confirm our metastable phase predictions. In particular, we identify the previously ambiguous structure of n-diamond as a cubic-analog of diaphite-like lonsdaelite phase.

7.
Phys Rev Lett ; 127(22): 227401, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34889631

##### RESUMO

Engineering novel states of matter with light is at the forefront of materials research. An intensely studied direction is to realize broken-symmetry phases that are "hidden" under equilibrium conditions but can be unleashed by an ultrashort laser pulse. Despite a plethora of experimental discoveries, the nature of these orders and how they transiently appear remain unclear. To this end, we investigate a nonequilibrium charge density wave (CDW) in rare-earth tritellurides, which is suppressed in equilibrium but emerges after photoexcitation. Using a pump-pump-probe protocol implemented in ultrafast electron diffraction, we demonstrate that the light-induced CDW consists solely of order parameter fluctuations, which bear striking similarities to critical fluctuations in equilibrium despite differences in the length scale. By calculating the dynamics of CDW fluctuations in a nonperturbative model, we further show that the strength of the light-induced order is governed by the amplitude of equilibrium fluctuations. These findings highlight photoinduced fluctuations as an important ingredient for the emergence of transient orders out of equilibrium. Our results further suggest that materials with strong fluctuations in equilibrium are promising platforms to host hidden orders after laser excitation.

8.
Adv Mater ; 33(37): e2101875, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34331368

##### RESUMO

On-chip dynamic strain engineering requires efficient micro-actuators that can generate large in-plane strains. Inorganic electrochemical actuators are unique in that they are driven by low voltages (≈1 V) and produce considerable strains (≈1%). However, actuation speed and efficiency are limited by mass transport of ions. Minimizing the number of ions required to actuate is thus key to enabling useful "straintronic" devices. Here, it is shown that the electrochemical intercalation of exceptionally few lithium ions into WTe2 causes large anisotropic in-plane strain: 5% in one in-plane direction and 0.1% in the other. This efficient stretching of the 2D WTe2 layers contrasts to intercalation-induced strains in related materials which are predominantly in the out-of-plane direction. The unusual actuation of Lix WTe2 is linked to the formation of a newly discovered crystallographic phase, referred to as Td', with an exotic atomic arrangement. On-chip low-voltage (<0.2 V) control is demonstrated over the transition to the novel phase and its composition. Within the Td'-Li0.5- Î´ WTe2 phase, a uniaxial in-plane strain of 1.4% is achieved with a change of Î´ of only 0.075. This makes the in-plane chemical expansion coefficient of Td'-Li0.5-Î´ WTe2 far greater than of any other single-phase material, enabling fast and efficient planar electrochemical actuation.

9.
Water Res ; 197: 117083, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33813168

##### RESUMO

Particulate organic carbon (POC) sources, which regulate dissolved organic carbon, sediment organic carbon, and inorganic carbon via deposition, degradation, and mineralization, play an important role in lake ecosystems. Linear or Bayesian algorithms on isotope and n-alkanes have been widely used to identify the source proportion of organic carbon. However, the applicability of these methods is ambiguous because of the unilateral advantages of each model and trace factors. To test the applicability of the various methods for identifying POC sources, we analyzed dual isotopes and n-alkanes in surface water samples of Lake Taihu, and Multi-source mixing model and Bayesian mixing model were used to distinguish between endogenous and exogenous contributions. Carbon isotope presented a clear advantage in West Taihu (-21.85 ± 0.78) and Southwest Taih (-22.61 ± 1.35); nitrogen isotope also showed high values in Meiliang Bay (9.76 ± 0.92). The majority of the lake was dominated by short-chain n-alkanes, except for East Taihu Lake (dominated by medium-chain n-alkanes) and areas with riverine input (dominated by long-chain n-alkanes). Different principles between the Bayesian mixing model (based on the Markov Chain Monte Carlo algorithm) and the Multi-source mixing model (based on linear estimation) caused discrepancies in the estimations of source contributions. But the fraction of chemical compounds during the migration process, and the overlap of potential sources play important role in the inconsistency of results. The estimations from the different models were consistent in indicating the dominance of endogenous organic carbon in Lake Taihu (mean of 60.18 ± 20.26%), particularly in the north and western regions (West Taihu, Meiliang Bay, and Southwest Taihu). This was likely due to algal aggregation influenced by human activities and climatic factors.

##### Assuntos
Carbono , Sedimentos Geológicos , Alcanos , Teorema de Bayes , Carbono/análise , Isótopos de Carbono/análise , China , Ecossistema , Monitoramento Ambiental , Humanos , Lagos
10.
Inorg Chem ; 60(7): 4236-4242, 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33417439

##### RESUMO

It is of great research interest to understand the nanostructures contributing to the activity observed in the reduction of oxygen by non-platinum group metal (PGM) electrocatalysts in acidic media. Iron- and nitrogen-containing carbon networks are often the most studied structures, among which single-atom iron-coordinated nitrogen (FeNx) moieties have often been proposed to be the structures leading to the high activity in these non-PGM electrocatalysts. Iron nanoparticles embedded within a carbon support are also formed under certain conditions as a result of the synthetic processes in making non-PGM electrocatalysts. In this study, we present a study to understand the oxygen reduction reaction (ORR) activity of prepared iron- and nitrogen-containing non-PGM electrocatalysts obtained through the pyrolysis of metal-organic framework (MOF) precursors. We studied the structure-property relationship among nanostructures made from the MOF precursor ZIF-8 under different pyrolysis conditions. Density functional theory calculations were used to explain the effect of structural moieties on the ORR activity. Our results suggest that iron-coordinated C-N structures and iron nanoparticles act synergistically to catalyze the ORR.

11.
Nano Lett ; 21(19): 8051-8057, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34529439

##### RESUMO

Vertically stacked transition metal dichalcogenide-graphene heterostructures provide a platform for novel optoelectronic applications with high photoresponse speeds. Photoinduced nonequilibrium carrier and lattice dynamics in such heterostructures underlie these applications but have not been understood. In particular, the dependence of these photoresponses on the twist angle, a key tuning parameter, remains elusive. Here, using ultrafast electron diffraction, we report the simultaneous visualization of charge transfer and electron-phonon coupling in MoS2-graphene heterostructures with different stacking configurations. We find that the charge transfer timescale from MoS2 to graphene varies strongly with twist angle, becoming faster for smaller twist angles, and show that the relaxation timescale is significantly shorter in a heterostructure as compared to a monolayer. These findings illustrate that twist angle constitutes an additional tuning knob for interlayer charge transfer in heterobilayers and deepen our understanding of fundamental photophysical processes in heterostructures, of importance for future applications in optoelectronics and light harvesting.

12.
Clin Cardiol ; 44(10): 1416-1421, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34480383

##### RESUMO

INTRODUCTION: Left atrial appendage (LAA) thrombus in patients with atrial fibrillation is usually detected by transesophageal echocardiography (TEE). Intracardiac echocardiography (ICE) can be a suitable alternative to detect thrombosis. However, the effectiveness of the two methods for detecting LAA thrombus is still unclear, we performed a meta-analysis that compared ICE versus TEE for LAA thrombosis. METHODS: We searched PubMed, Cochrane Library, and Embase for published abstracts and manuscripts on June 1, 2020. The analysis was performed using RevMan 5.3, STATA 15, and Meta-Disc 1.4. RESULTS: Eight studies consists of 1108 patients (TEE = 558 vs. ICE = 550) were included. The average sensitivity of ICE and TEE to diagnose LAA thrombus is 1.0 (95% CI: 0.91-1.00) versus 0.68 (95% CI: 0.49-0.83), and specificity of ICE and TEE to diagnosis of LAA thrombus is 1.0 (95% CI: 0.99-1.00) versus 0.98 (95% CI: 0.96-0.99). The AUC of ICE and TEE is 0.9846 (SEAUC = 0.0196) and 0.9655 (SEAUC = 0.0401), and the Q* statistics is 0.9462 (SEQ* = 0.0406) and 0.9127 (SEQ * = 0.0616), respectively. Z test was performed on Q* statistics (Z = 0.45, p > .05). CONCLUSION: The ICE and TEE have similar diagnostic efficacy for LAA thrombosis, but the ICE has higher sensitivity. Compared with TEE, ICE may be more advantages and prospects for clinical application.

##### Assuntos
Apêndice Atrial , Fibrilação Atrial , Cardiopatias , Trombose , Apêndice Atrial/diagnóstico por imagem , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/diagnóstico por imagem , Ecocardiografia Transesofagiana , Cardiopatias/diagnóstico por imagem , Humanos , Trombose/diagnóstico por imagem , Trombose/etiologia
13.
ACS Nano ; 14(7): 8449-8458, 2020 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-32538617

##### RESUMO

The inspection of Friedel's law in ultrafast electron diffraction (UED) is important to gain a comprehensive understanding of material atomic structure and its dynamic response. Here, monoclinic gallium telluride (GaTe), as a low-symmetry, layered crystal in contrast to many other 2D materials, is investigated by mega-electronvolt UED. Strong out-of-phase oscillations of Bragg peak intensities are observed for Friedel pairs, which does not obey Friedel's law. As evidenced by the preserved mirror symmetry and supported by both kinematic and dynamic scattering simulations, the intensity oscillations are provoked by the lowest-order longitudinal acoustic breathing phonon. Our results provide a generalized understanding of Friedel's law in UED and demonstrate that by designed misalignment of surface normal and primitive lattice vectors, coherent lattice wobbling and effective shear strain can be generated in crystal films by laser pulse excitation, which is otherwise hard to achieve and can be further utilized to dynamically tune and switch material properties.

14.
Chemosphere ; 248: 126015, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32032874

##### RESUMO

Sixteen polycyclic aromatic hydrocarbons (PAHs) in a sediment core from Dianchi Lake, southwest China, were analysed. The influence of changes in China's energy structure for 2-6 ringed PAHs was investigated to assess sources and the impact of socioeconomic development on temporal changes in concentrations. The concentration of the ΣPAH16 ranged from 746 to 2293 ng g-1. Prior to the 1960s relatively low concentrations of the ΣPAH16 and a larger proportion of 2-3-ring PAHs indicated that biomass combustion was the main source of PAHs. A rapid increase in the concentrations of 2-3 ring PAHs between 1975 and 2004 was attributed to population growth and coal consumption. A declining trend since 2004 was interpreted as being due to local changes in household energy usage. Increased concentrations of 4-ring PAH between 1975-2005 and 5-6-ring PAHs between the 1980s to 2004 showed correlations with increased coal consumption and the number of motor vehicles, respectively. These were caused by rapid urbanization and industrialization in the Dianchi watershed following the implementation of the Reform and Open Policy in 1978. A subsequent decline in the concentrations of 4-ring and 5-6-ring PAHs may have been due to decreased coal consumption and improvements in emission standards, respectively. Source apportionment by a PMF model revealed that coal combustion (29.2%), vehicle emissions (24.2%), petrogenic sources (21.8%), and biomass combustion (24.9%) were the sources of PAHs in the lake sediment core, and that coal combustion was the most important regional source of PAHs pollution.

##### Assuntos
Monitoramento Ambiental , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Poluição Química da Água/estatística & dados numéricos , Biomassa , China , Carvão Mineral/análise , Desenvolvimento Econômico , Poluição Ambiental/análise , Sedimentos Geológicos/química , Desenvolvimento Industrial , Lagos/química , Urbanização , Emissões de Veículos/análise
15.
Rev Sci Instrum ; 89(4): 045113, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29716329

##### RESUMO

The streak tubes with a large effective photocathode area, large effective phosphor screen area, and high photocathode radiant sensitivity are essential for improving the field of view, depth of field, and detectable range of the multiple-slit streak tube imaging lidar. In this paper, a high spatial resolution, large photocathode area, and compact meshless streak tube with a spherically curved cathode and screen is designed and tested. Its spatial resolution reaches 20 lp/mm over the entire Φ28 mm photocathode working area, and the simulated physical temporal resolution is better than 30 ps. The temporal distortion in our large-format streak tube, which is shown to be a non-negligible factor, has a minimum value as the radius of curvature of the photocathode varies. Furthermore, the photocathode radiant sensitivity and radiant power gain reach 41 mA/W and 18.4 at the wavelength of 550 nm, respectively. Most importantly, the external dimensions of our streak tube are no more than Φ60 mm × 110 mm.

16.
Biochem Biophys Res Commun ; 467(4): 645-50, 2015 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-26498532

##### RESUMO

The aim of this study was to evaluate the impact of Ang-(1-7) on calcium transient (CaT) in cardiomyocytes during the pathogenesis of heart failure. Cardiac dysfunction was induced by ligation of left anterior descending coronary artery in adult SD rats. Randomly selected rats were ligated and continuously infused with Ang-(1-7) [HF + Ang-(1-7) group] or saline (HF + saline group) via osmotic minipumps. After 28 days, hemodynamic parameters, the CaT, and the heart rate threshold of CaT alternans (CaT-Alt) were measured. Continuous Ang-(1-7) treatment could attenuate the impairment of cardiac function following LAD ligation. The amplitudes (F/F0) and 50%/90% recovery time of CaT were significantly different among HF + saline, HF + Ang-(1-7) and Sham-operated group. Compared to the Sham-operated group, the HF + saline group showed decreased CaT amplitude, and a prolonged 50%/90% CaT recovery time; Ang-(1-7) significantly improved these abnormalities. Compared with Sham-operated group, heart rate thresholds of CaT-Alt significantly reduced in HF + saline group, and Ang-(1-7) partly restored it. These findings indicate that Ang-(1-7) attenuates the CaT disturbance and increases the heart rate threshold of CaT-Alt during the pathogenesis of ischemic heart failure.

##### Assuntos
Angiotensina I/administração & dosagem , Cálcio/metabolismo , Coração/fisiopatologia , Isquemia Miocárdica/metabolismo , Miocárdio/metabolismo , Fragmentos de Peptídeos/administração & dosagem , Angiotensina I/farmacologia , Animais , Canais de Cálcio Tipo L/efeitos dos fármacos , Canais de Cálcio Tipo L/fisiologia , Hemodinâmica/efeitos dos fármacos , Masculino , Isquemia Miocárdica/fisiopatologia , Fragmentos de Peptídeos/farmacologia , Ratos , Ratos Sprague-Dawley
17.
J Cardiovasc Pharmacol ; 63(3): 259-64, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24193198

##### RESUMO

Accumulating evidence indicates that angiotensin-(1-7) [Ang-(1-7)] offers protective effects against ischemia-reperfusion (I/R) induced arrhythmias and contractile dysfunction, which are related to disturbances of intracellular calcium homeostasis. However, whether or not Ang-(1-7) regulates intracellular calcium in I/R is not clear. To shed light on this issue, we carried out studies with a cellular model of simulated I/R in isolated rat ventricular myocytes and measured calcium transients using laser scanning confocal microscopy. Our results showed that Ang-(1-7) had no effects on the calcium transient in myocytes superfused with normal solution; however, in myocytes of simulated I/R, Ang-(1-7) significantly attenuated the increased diastolic intracellular Ca during reperfusion, restored the decreased peak Ca of calcium transient during ischemia, and reversed the decreased amplitude of calcium transient throughout the I/R periods. Additionally, Ang-(1-7) significantly suppressed the reactive oxygen species production in I/R, especially during the ischemic phase. These data indicated that Ang-(1-7) affords significant cytoprotective effects through directly improving calcium homeostasis independent of its anti-oxidative action. Most notably, the effects of Ang-(1-7) on intracellular Ca dynamics manifests only in the diseased states, that is, I/R. This unique property suggests that upregulation of Ang-(1-7) expression and/or activation of the Ang-(1-7)/Mas signaling cascade is a highly desirable strategy for the treatment of myocardial impairment induced by I/R.

##### Assuntos
Angiotensina I/farmacologia , Cálcio/metabolismo , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Fragmentos de Peptídeos/farmacologia , Animais , Citoproteção/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Masculino , Microscopia Confocal , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Ratos , Ratos Sprague-Dawley
18.
J Neurosci Res ; 91(2): 249-61, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23151870

##### RESUMO

Epidural hematoma (EDH) is a type of life-threatening traumatic brain injury. Little is known about the extent to which EDH may cause neural damage and regenerative response in the cerebral cortex. Here we attempted to explore these issues by using guinea pigs as an experimental model. Unilateral EDH was induced by injection of 0.1 ml autologous blood into the extradural space, with experimental effects examined at 7, 14, 30, and 60 days postlesion. An infarct developed in the cortex deep to the EDH largely after 7 days postlesion, with neuronal death occurred from layers I to V in the central infarct region, as evidenced by loss of immunoreactivity (IR) for neuron-specific nuclear antigen (NeuN). Glial fibrillary acidic protein (GFAP) IR appeared as a cellular band surrounding the infarct and extending into the periinfarct cortex along the pia. Doublecortin (DCX) IR emerged in these same areas, with labeled cells appearing as astrocytic and neuronal profiles. DCX/GFAP colocalization was found in these regions commonly at 7 and 14 days postlesion, whereas DCX/NeuN-colabeled neurons were detectable at 30 and 60 days postlesion. Subpopulations of GFAP-, DCX-, or NeuN-immunoreactive cells colocalized with the endogenous proliferative marker Ki-67 or bromodeoxyuridine (BrdU) after pulse-chase with this birth-dating marker. The results suggest that experimental EDH can cause severe neuronal loss, induce significant glial activation, and promote a certain degree of local neuronal genesis in adult guinea pig neocortex. These findings point to potential therapeutic targets for improving neuronal recovery in clinical management of EDH.

##### Assuntos
Infarto Encefálico/etiologia , Córtex Cerebral/patologia , Hematoma Epidural Craniano/complicações , Neurogênese/fisiologia , Neuroglia/patologia , Animais , Infarto Encefálico/patologia , Bromodesoxiuridina/metabolismo , Diferenciação Celular , Modelos Animais de Doenças , Proteínas do Domínio Duplacortina , Lateralidade Funcional , Regulação da Expressão Gênica/fisiologia , Proteína Glial Fibrilar Ácida , Cobaias , Masculino , Proteínas Associadas aos Microtúbulos/metabolismo , Neuropeptídeos/metabolismo , Fosfopiruvato Hidratase/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismo
19.
Turk Neurosurg ; 22(5): 547-57, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23015330

##### RESUMO

AIM: We present the long-term outcomes as well as their correlation with tumor size in 127 consecutive patients harboring large MSWM after microsurgical treatment. MATERIAL AND METHODS: The retrospective analysis of clinical data and follow-up data of 127 microsurgical treated patients with MSWM was performed. The mean maximum diameter of tumors was 5.2cm (ranged 1.5-10.0cm). RESULTS: 104 cases (81.9%) achieved gross total resection. There was no operative mortality. Detailed follow-up data was available in 120 cases for a mean duration of 81.6 months (12-216 months). The permanent morbidity was 14.2%. The mean KPS score 1 year after surgery was 90.6 (ranged 60-100). Among 74 patients of preoperative visual acuity (VA) impairment, postoperative VA improved in 42 cases (56.8%), unchanged in 30 (40.5%), and deteriorated in 2 (2.7%). MR images revealed tumor recurrence after total resection in 10 cases (10.2%) and tumor progression after subtotal resection in 10 cases (45.5%). CONCLUSION: Tumor recurrence was the major risk in the long run, thus the initial surgery was extremely important and hence should be aggressive. The size of tumor affected the extent of tumor removal determining clinical outcomes including VA improvement and KPS score immediately after surgery; however, it was not correlated with long-term overall outcomes.

##### Assuntos
Meningioma/patologia , Meningioma/cirurgia , Microcirurgia/métodos , Procedimentos Neurocirúrgicos/métodos , Neoplasias Cranianas/patologia , Neoplasias Cranianas/cirurgia , Osso Esfenoide/patologia , Osso Esfenoide/cirurgia , Adolescente , Adulto , Idoso , Criança , Progressão da Doença , Feminino , Seguimentos , Humanos , Avaliação de Estado de Karnofsky , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Exame Neurológico , Complicações Pós-Operatórias/epidemiologia , Qualidade de Vida , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Adulto Jovem
20.
Exp Neurol ; 216(2): 342-56, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19166833

##### RESUMO

DCX-immunoreactive (DCX+) cells occur in the piriform cortex in adult mice and rats, but also in the neocortex in adult guinea pigs and rabbits. Here we describe these cells in adult domestic cats and primates. In cats and rhesus monkeys, DCX+ cells existed across the allo- and neocortex, with an overall ventrodorsal high to low gradient at a given frontal plane. Labeled cells formed a cellular band in layers II and upper III, exhibiting dramatic differences in somal size (5-20 microm), shape (unipolar, bipolar, multipolar and irregular), neuritic complexity and labeling intensity. Cell clusters were also seen in this band, and those in the entorhinal cortex extended into deeper layers as chain-like structures. Densitometry revealed a parallel decline of the cells across regions with age in cats. Besides the cellular band, medium-sized cells with weak DCX reactivity resided sparsely in other layers. Throughout the cortex, virtually all DCX+ cells co-expressed polysialylated neural cell adhesion molecule. Medium to large mature-looking DCX+ cells frequently colocalized with neuron-specific nuclear protein and gamma-aminobutyric acid (GABA), and those with a reduced DCX expression also partially co-labeled for glutamic acid decarboxylase, parvalbumin, calbindin, beta-nicotinamide adenine dinucleotide phosphate diaphorase and neuronal nitric oxide synthase. Similar to cats and monkeys, small and larger DCX+ cells were detected in surgically removed human frontal and temporal cortices. These data suggest that immature neurons persist into adulthood in many cortical areas in cats and primates, and that these cells appear to undergo development and differentiation to become functional subgroups of GABAergic interneurons.

##### Assuntos
Córtex Cerebral/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas Associadas aos Microtúbulos/metabolismo , Neurônios/metabolismo , Neuropeptídeos/metabolismo , Ácido gama-Aminobutírico/metabolismo , Adulto , Fatores Etários , Animais , Animais Recém-Nascidos , Gatos , Córtex Cerebral/citologia , Córtex Cerebral/crescimento & desenvolvimento , Criança , Proteínas do Domínio Duplacortina , Proteína Duplacortina , Feminino , Humanos , Macaca mulatta , Masculino , Pessoa de Meia-Idade , NADP/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/classificação , Óxido Nítrico Sintase Tipo I/metabolismo
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