Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
1.
Cell Mol Biol (Noisy-le-grand) ; 70(4): 147-151, 2024 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-38678613

RESUMO

Vitiligo belongs to a frequent chronic autoimmune skin disease with the features of pigmented plaques on the diseased skin along with potential damage of melanocytes. There are many factors underlying the pathogenesis of vitiligo, among which oxidative stress is extensively regarded to be the critical factor leading to the loss of melanocytes. The changed redox state resulting from oxidative stress, containing ROS overproduction along with the reduced activity of the skin's antioxidant system, makes melanocytes less resistant to exogenous or endogenous stimuli, and ultimately pushes normal defense mechanisms, resulting in the loss of melanocytes. Given the crucial potential of innate together with adaptive immunity in vitiligo, there is growing evidence of a relation between oxidative stress and autoimmunity. Our review offers estimable insights into the possible properties of oxidative stress and autoimmunity in pathogenesis of vitiligo, as well as the potential role of antioxidant-based supportive therapy in vitiligo repigmentation, providing a hopeful value for further research and development of effective treatments.


Assuntos
Autoimunidade , Melanócitos , Estresse Oxidativo , Vitiligo , Vitiligo/imunologia , Vitiligo/metabolismo , Humanos , Melanócitos/metabolismo , Melanócitos/imunologia , Antioxidantes/metabolismo , Antioxidantes/uso terapêutico , Espécies Reativas de Oxigênio/metabolismo , Pigmentação da Pele , Animais
2.
Opt Express ; 31(21): 34232-34239, 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37859184

RESUMO

Vortex beams have attracted much attention due to their unique rotational Doppler effect. With the in-depth study of vortex beams, many new vortex beams have been proposed gradually, while the detection of fluid motion is of great significance for the study of ocean turbulence. Based on the rotational Doppler effect of the grafted perfect vortex beam, we propose a non-embedded optical method for real-time detection of the magnitude and direction of fluid velocity and establish a two-dimensional fluid model for simulation verification. It is proved that the grafted perfect vortex beam can detect the magnitude and direction of the fluid velocity at the same time, which may provide a new way and theoretical support for the detection of fluid motion direction.

3.
Opt Express ; 31(26): 44028-44043, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38178484

RESUMO

Digital holographic imaging has emerged as a transformative technology with significant implications for AR/VR devices. However, existing techniques often suffer from limitations such as restricted field of view (FOV), high power consumption, and contrast distortion. This paper introduces an innovative optical phased array (OPA)-based chip, integrating polarization, amplitude, and phase multiplexing for enhanced complex amplitude holographic imaging. A checkerboard-style staggered array is employed in the control strategy, substantially reducing power consumption and enabling the potential for large-scale array integration. To further enhance imaging quality, we introduce what we believe are two novel calibration strategies: one is to achieve super-resolution through block imaging methods, and the other is to image using sparse aperture methods. These advancements not only provide a robust foundation for high-quality holographic imaging, but also present a new paradigm for overcoming the inherent limitations of current active holographic imaging devices. Due to challenges in chip fabrication, the research is primarily simulation-based. Nevertheless, this work presents meaningful advancements in digital holographic imaging for AR/VR applications and provides a foundation for future experimental validations.

4.
Opt Express ; 30(18): 31577-31583, 2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-36242237

RESUMO

Based on the laser Doppler coherent detection method, a laser Doppler Non-Line-of Sight imaging technique (LD-NLOS) is proposed to obtain a series of effective information about the detected objects outside the line of sight. According to the analysis of the frequency and light intensity characteristics of the scattered signal, the information of the detected object hidden in the intermediate scattering surface is decoded. Without relying on complicated back-end algorithm processing and expensive experimental detection cost, the proposed LD-NLOS technique can detect the target vibration velocity and stably reconstruct its 2D shape.

5.
J Am Chem Soc ; 143(17): 6586-6592, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33885294

RESUMO

We report the reversible adsorption of ammonia (NH3) up to 9.9 mmol g-1 in a robust Al-based metal-organic framework, MFM-303(Al), which is functionalized with free carboxylic acid and hydroxyl groups. The unique pore environment decorated with these acidic sites results in an exceptional packing density of NH3 at 293 K (0.801 g cm-3) comparable to that of solid NH3 at 193 K (0.817 g cm-3). In situ synchrotron X-ray diffraction and inelastic neutron scattering reveal the critical role of free -COOH and -OH groups in immobilizing NH3 molecules. Breakthrough experiments confirm the excellent performance of MFM-303(Al) for the capture of NH3 at low concentrations under both dry and wet conditions.

6.
J Am Chem Soc ; 143(8): 3153-3161, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33606937

RESUMO

Ammonia (NH3) is a promising energy resource owing to its high hydrogen density. However, its widespread application is restricted by the lack of efficient and corrosion-resistant storage materials. Here, we report high NH3 adsorption in a series of robust metal-organic framework (MOF) materials, MFM-300(M) (M = Fe, V, Cr, In). MFM-300(M) (M = Fe, VIII, Cr) show fully reversible capacity for >20 cycles, reaching capacities of 16.1, 15.6, and 14.0 mmol g-1, respectively, at 273 K and 1 bar. Under the same conditions, MFM-300(VIV) exhibits the highest uptake among this series of MOFs of 17.3 mmol g-1. In situ neutron powder diffraction, single-crystal X-ray diffraction, and electron paramagnetic resonance spectroscopy confirm that the redox-active V center enables host-guest charge transfer, with VIV being reduced to VIII and NH3 being oxidized to hydrazine (N2H4). A combination of in situ inelastic neutron scattering and DFT modeling has revealed the binding dynamics of adsorbed NH3 within these MOFs to afford a comprehensive insight into the application of MOF materials to the adsorption and conversion of NH3.

7.
Inorg Chem ; 59(19): 14493-14500, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32951430

RESUMO

Blue phosphorescent tetradentate pyridyl-carbolinyl Pt(II) complexes, Pt(ppzOclpy-Me), Pt(ppzOclpy-iPr), and Pt(ppzOclpy-mesi), were purposefully synthesized and investigated with their photophysical and luminescent properties. The complexes, incorporating with carbolinyl moieties, have twisted planar structure. X-ray crystallography revealed that the intraligand N···H-C hydrogen bond reversely turned the twisty pyridyl moiety back into the chelating plane. Computational analyses confirmed that the metal-to-ligand charge-transfer transition character appears in the singlet manifolds. However, the ligand-centered transitions rule in their triplet states, which accounts for the phosphorescent emission. The Pt(II) complexes emit blue light with peak wavelengths (λmax) of 461-481 nm and moderate photoluminescent quantum yields (Φ = 34-46% in dichloromethane and Φ = 44-52% in films). The electroluminescent devices were fabricated by solution processes, giving blue emissions peaking at around 470 nm.

8.
J Phys Chem A ; 119(10): 1957-63, 2015 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-25715058

RESUMO

We consider the response of a laser-induced quadrupole-dipole collisional system driven by a strong dressing laser field with the aim of calculating the collisional cross section of a weak inducing laser probe. The addition of a second driving field to the traditional arrangement will cause magnitude changes of the spectra and modify the profile. The calculation results show that the bichromatic laser-induced collisional energy-transfer process can be an efficient way to probe Stark splitting of both the final state and intermediate state. The magnitude and position of the splitting spectral lines are strongly dependent on the intensity of the dressing laser field. The peak cross section almost reduces by a factor of 2 with the presence of the dressing laser. Also, in the antistatic wing, bright and dark lines are periodic, appearing with the increasing of the dressing laser intensity.

9.
Chem Sci ; 15(21): 8197-8203, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38817566

RESUMO

The functionalisation of organic linkers in metal-organic frameworks (MOFs) to improve gas uptake is well-documented. Although the positive role of free carboxylic acid sites in MOFs for binding gas molecules has been proposed in computational studies, relatively little experimental evidence has been reported in support of this. Primarily this is because of the inherent synthetic difficulty to prepare MOF materials bearing free, accessible -COOH moieties which would normally bind to metal ions within the framework structure. Here, we describe the direct binding of CO2 and C2H2 molecules to the free -COOH sites within the pores of MFM-303(Al). MFM-303(Al) exhibits highly selective adsorption of CO2 and C2H2 with a high selectivity for C2H2 over C2H4. In situ synchrotron X-ray diffraction and inelastic neutron scattering, coupled with modelling, highlight the cooperative interactions of adsorbed CO2 and C2H2 molecules with free -COOH and -OH sites within MFM-303(Al), thus rationalising the observed high selectivity for gas separation.

10.
Clin Cosmet Investig Dermatol ; 16: 1857-1864, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37483472

RESUMO

We present the first case of coma bullae observed in a 67-year-old woman due to pressure and ischemia associated with brachioradial artery. A skin biopsy taken from the ulcer border revealed extensive loss of the epidermis, fibrosis of dermis, mild infiltration by lymphocytes and neutrophils, and necrosis of the focal eccrine ducts. CT angiography of the right upper limb showed a high origin of the radial artery, meanwhile both high originating radial artery and the anastomoses were tortuous and were of relatively small caliber. The diagnosis of coma bullae was made. After tissue debridement, the skin lesions gradually recovered, leaving atrophic scars.

11.
J Am Chem Soc ; 134(25): 10341-4, 2012 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-22703183

RESUMO

We report the one-pot reactions of the 16e(-) half-sandwich complex CpCoS(2)C(2)B(10)H(10) (1), methyl propiolate, and 3e(-)-donor ligands, which lead to selective B-functionalization at carborane with cyclopentadienyl as a functional group at ambient temperature in good yields. Metal-promoted activations of both a B-H bond of the carborane and a C-H bond of the Cp unit take place sequentially in the cooperation of organic ligands. The reaction requires a 3e(-)-donor ligand and an activated alkyne and is therefore suitable for a broad range of substrates. This investigation provides a simple and efficient synthetic route to B-functionalized carborane derivatives.


Assuntos
Alcinos/química , Boranos/química , Ciclopentanos/química , Compostos de Sulfidrila/química , Cobalto/química , Modelos Moleculares
12.
Chemistry ; 18(10): 2812-24, 2012 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-22307561

RESUMO

Five metal-organic frameworks (MOFs) formed by [WS(4)Cu(x)](x-2) secondary building units (SBUs) and multi-pyridyl ligands are presented. The [WS(4)Cu(x)](x-2) SBUs function as network vertexes showing various geometries and connectivities. Compound 1 contains one-dimensional channels formed in fourfold interpenetrating diamondoid networks with a hexanuclear [WS(4)Cu(5)](3+) unit as SBU, which shows square-pyramidal geometry and acts as a tetrahedral node. Compound 2 contains brick-wall-like layer also with a hexanuclear [WS(4)Cu(5)](3+) unit as SBU. The [WS(4)Cu(5)](3+) unit in 2 is a new type of [WS(4)Cu(x)](x-2) cluster unit in which the five Cu(+) ions are in one plane with the W atom, forming a planar unit. Compound 3 shows a nanotubular structure with a pentanuclear [WS(4)Cu(4)](2+) unit as SBU, which is saddle-shaped and acts as a tetrahedral node. Compound 4 contains large cages formed between two interpenetrated (10,3)-a networks also with a pentanuclear [WS(4)Cu(4)](2+) unit acting as a triangular node. The [WS(4)Cu(4)](2+) unit in 4 is isomeric to that in 3 and first observed in a MOF. Compound 5 contains zigzag chains with a tetrahedral [WS(4)Cu(3)](+) unit as SBU, which acts as a V-shaped connector. The influence of synthesis conditions including temperature, ligand, anions of Cu(I) salts, and the ratio of [NH(4)](2)WS(4) to Cu(I) salt on the formation of these [WS(4)Cu(x)](x-2)-based MOFs were also studied. Porous MOF 3 is stable upon removal and exchange of the solvent guests, and when accommodating different solvent molecules, it exhibits specific colors depending on the polarity of incorporated solvent, that is, it shows a rare solvatochromic effect and has interesting prospects in sensing applications.

13.
Clin Cosmet Investig Dermatol ; 15: 1397-1402, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35910508

RESUMO

Co-infection of Mycobacterium tuberculosis (MTB) and Candida albicans with erythema on the face is rare. A familiar red spot on the face can easily lead to missed diagnosis and misdiagnosis. Untreated lupus vulgaris (LV) can form scar tissue. And the fungal infection that cannot be diagnosed and treated timely can also lead to failure of LV treatment, resulting in facial scarring, disfigurement, and psychological stress. In this study, we reported a case of a 58-year-old immunocompetent female co-infected with MTB and Candida albicans on her face. After anti-tuberculous and anti-fungal therapy, she recovered with no scar on her face.

14.
ACS Chem Neurosci ; 13(23): 3352-3361, 2022 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-36444509

RESUMO

Studies demonstrated that alumina nanoparticles (alumina NPs) impair spatial cognition and hippocampus-dependent synaptic plasticity. Although alumina NPs accumulate in the prefrontal cortex (PFC), their effects on PFC-mediated neuronal and cognitive function have been not yet documented. Here, alumina NPs (10 or 20 µg/kg of body weight) were bilaterally injected into the medial PFC (mPFC) of adult rats, and the levels of glycogen synthase kinase 3ß (GSK3ß) and the brain-derived neurotrophic factor (BDNF) were detected. The PFC-dependent working memory task with one-minute or three-minute delay time was conducted. Meanwhile, the neuronal correlates of working memory performance were recorded. The specific expression of neuronal BDNF was assessed by colabeled BDNF expression with the neuronal nuclear antigen (NeuN). Whole-cell patch-clamp recordings were employed to detect neuronal excitability. Intra-mPFC alumina NP infusions significantly enhanced the expression of GSK3ß but reduced the phosphorylation of GSK3ß (pGSK3ß) and BDNF levels more severely at a dose of 20 µg/kg. Alumina NPs acted in a dose-dependent manner to impair working memory. The neuronal expression of BDNF in the 20 µg/kg group was markedly declined compared with the 10 µg/kg group. During the delay time, the neuronal frequency of pyramidal cells but not interneurons was significantly weakened. Furthermore, both the frequency and amplitude of the excitatory postsynaptic currents (EPSCs) were descended in the mPFC slices. Additionally, the infusion of GSK3ß inhibitor SB216763 or BDNF could effectively attenuate the impairments in neuronal correlate, neuronal activity, and working memory. From the perspective of the identified GSK3ß/BDNF pathway, these findings demonstrated for the first time that alumina NPs exposure can be a risk factor for prefrontal neuronal and cognitive functions.


Assuntos
Fator Neurotrófico Derivado do Encéfalo , Memória de Curto Prazo , Animais , Ratos , Óxido de Alumínio/farmacologia , Córtex Pré-Frontal , Transdução de Sinais
15.
J Am Chem Soc ; 133(12): 4172-4, 2011 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-21375252

RESUMO

A nanotubular metal-organic framework (MOF), {[(WS(4)Cu(4))I(2)(dptz)(3)]·DMF}(n) (dptz = 3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine, DMF = N,N-dimethylformamide) for sensing small solvent molecules is presented. When accommodating different solvent molecules as guests, the resulting inclusion compounds exhibit different colors depending on the solvent guests, and more interestingly, the band gaps of these solvent-included complexes are in linear correlation with the polarity of the guest solvents. The solvent molecules can be sensed by the changes of UV-vis spectra of the corresponding inclusion compounds, showing a new way of signal transduction as a new kind of sensor. The sensing by such a MOF occurs within the channel-containing material rather than on the external surface.


Assuntos
Nanoestruturas/química , Compostos Organometálicos/química , Modelos Moleculares , Solventes/química , Propriedades de Superfície
16.
RSC Adv ; 11(61): 38820-38828, 2021 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-35493231

RESUMO

One key challenge in oligonucleotide sequence sensing is to achieve multiplexed DNA detection in one sensor. Herein, a simple and efficient fluorescent biosensing platform is constructed to simultaneously detect multiplexed DNA depending on porous organic polymer (POP) nanospheres. The developed sensor is based on the concept that the POP nanospheres can efficiently quench the fluorescence emission of dye-labeled single-stranded DNA (ssDNA). Fluorescence quenching is achieved by the non-covalent assembly of multiple probes on the surface of POP nanospheres through electrostatic attraction and π-π stacking interactions, in which the electrostatic attraction plays a more critical role than π-π stacking. The formed dsDNA could be released off the surface of POP via hybridizing with the target DNA. Consequently, the target DNA can be quickly detected by fluorescence recovery. The biosensor could sensitively and specifically identify three target DNAs in the range of 0.1 to 36 nM, and the lowest detection limits are 50 pM, 100 pM, and 50 pM, respectively. It is noteworthy that the proposed platform is successfully applied to detect DNA in human serum. We perceive that the proposed sensing system represents a simple and sensitive strategy towards simultaneous and multiplexed assays for DNA monitoring and early clinical diagnosis.

17.
ACS Appl Mater Interfaces ; 13(44): 52833-52839, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34705419

RESUMO

Described herein is a stable complex, Pt(mpzpyOczpy-mesi), embodying efficient, narrow blue emission. The highly twisted structure of the complex improves the stability and efficiency of photo- and electroluminescence by reducing the intermolecular interactions. The complex in solution shows high photoluminescence efficiency (>95%) and radiative decay rate (Kr = 2.9 × 105 s-1) with a narrow emission spectrum. The bottom-emitting phosphorescent device, BE1, exhibits durable deep blue emission with CIE coordinates of (0.145, 0.166) and 5.2 h of LT50 at an initial luminance of 685 cd/m2. Top-emitting devices, TE1 and TE2, achieve ultrapure blue color with CIEx,y values of (0.141, 0.068) and (0.140, 0.071), respectively. TE4 shows high brightness of 3405 cd m-2 at 50 mA m-2, EQE of 10.2% at 1000 cd/m2, and almost negligible color deviation around (0.135, 0.096) at viewing angles of 0°-60°.

18.
Dalton Trans ; 50(23): 7944-7948, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34096564

RESUMO

Three coordination polymers (CPs) were synthesized by using CdII, fluorescent 9,10-di(4-pyridyl)anthracene (dpa), and cyclohexane-1,4-dicarboxylic acid (H2cda), and they are [Cd2(dpa)2(cda)Cl2]n (1), [Cd(dpa)2(cda)]n (2) and [Cd(dpa)(cda)(H2O)]n (3). Both 1 and 2 are fluorescent and contain nonporous layers. 3 is an isomer of 2 and contains a porous diamondoid network. Fluorescent mixed matrix membranes were prepared by dispersing the particles of 1 or 2 within the matrix of polymethyl methacrylate, and showed high sensitivity and selectivity for detecting Cr2O72- in water. Both stability and recyclability of the MMMs were remarkably higher than those of the CP powders.

19.
Opt Express ; 18(20): 21062-73, 2010 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-20941002

RESUMO

A three-state model for calculating the cross section of laser-induced dipole-quadrupole collisional energy transfer in Sr-Ca system is presented. The motion equations for the probability amplitudes of the three intermediate states are obtained. The expression of the cross section is derived. Various factors including field intensity, relative speed, system temperature which influence the collisional cross section are discussed to illustrate the features of the dipole-quadrupole laser-induced collisional energy transfer (LICET)process. Calculating results show that the peak of the LICET profiles moves to the red, the tuning range of the profiles obviously becomes narrower with the laser field intensity increasing and a cross section of 1.25 × 10(-13)cm(2) at a laser intensity of 8.29 × 10(9)W/cm(2) is obtained. Our results indicate that dipole-quadrupole LICET process can be the effective way to transfer energy selectively from a storage state of arbitrary parity to a target state of arbitrary parity.

20.
Dalton Trans ; 49(17): 5618-5624, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32285086

RESUMO

Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) with tunable pore sizes, shapes and functionalities have excellent prospects in many applications, such as carbon capture. Molecular sieving can usually enable very high CO2 adsorption selectivity but has rarely been achieved, because it is difficult to precisely control the pore size in the range of 3-4 Å. We report here three MOF isomers built from CdII, terephthalic acid and 3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine with the same stoichiometric ratio, among which 1 and 2 are framework-catenation isomers and 2 and 3 are framework-topological isomers. 1 contains 2-fold interpenetrated networks (topology of pcu) and 1D ultra-micropores and shows highly selective adsorption of CO2 over N2 and CH4, which is mainly ascribed to the molecular sieving effect of the framework. 2 contains a pcu network with 3D interconnected micropores, and 3 contains a kag network with much larger pores of 15 Å. Framework isomerization, in this case, was shown to be a feasible way of tuning the pore size of a MOF for selective CO2 adsorption. The effects of hydrothermal reaction conditions and additives on the structures and the formation of the MOF isomers were also studied.

SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa