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1.
Molecules ; 26(11)2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34200163

RESUMO

Tea polysaccharides (TPSs) are one of the main bioactive constituents of tea with various biological activities such as hypoglycemic effect, antioxidant, antitumor, and immunomodulatory. The bioactivities of TPSs are directly associated with their structures such as chemical composition, molecular weight, glycosidic linkages, and conformation among others. To study the relationship between the structures of TPSs and their bioactivities, it is essential to elucidate the structure of TPSs, particularly the fine structures. Due to the vast variation nature of monosaccharide units and their connections, the structure of TPSs is extremely complex, which is also affected by several major factors including tea species, processing technologies of tea and isolation methods of TPSs. As a result of the complexity, there are few studies on their fine structures and chain conformation. In the present review, we aim to provide a detailed summary of the multiple factors influencing the characteristics of TPS chemical structures such as variations of tea species, degree of fermentation, and preparation methods among others as well as their applications. The main aspects of understanding the structural difference of TPSs and influencing factors are to assist the study of the structure and bioactivity relationship and ultimately, to control the production of the targeted TPSs with the most desired biological activity.


Assuntos
Polissacarídeos/química , Chá/química , Antioxidantes/química , Fermentação/fisiologia , Imunomodulação/efeitos dos fármacos , Monossacarídeos/química
2.
J Agric Food Chem ; 69(21): 5938-5947, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34003645

RESUMO

Theaflavins (TFs), formed by the dimerization of green tea catechins during "fermentation" to prepare black tea, possess antioxidant and anti-inflammatory effects. Reported efficacious effects of black tea (∼2% of TFs) or related products come from catechins unless TFs are assayed. The present study aimed to target the preparation of black tea extract (BTE) enriched with theaflavin mono- and digallates majorly from dry tea leaves in aqueous media versus traditional fermentation of fresh leaves. We further investigated the protective function of the produced BTE on rat liver and kidney injury induced by CCl4 and its underlying molecular mechanisms. The results showed that BTE suppressed the activation level of hepatic stellate cells (HSCs), and the secretion of collagen was induced by CCl4. The relative expression levels of TGF-ß, p-ERK1/ERK1, p-ERK2/ERK2, p-Smad1/Smad1, and p-Smad2/Smad2 were reduced to 56, 68, 56, 44, and 32%, respectively, compared with those of CCl4-treated rats. Therefore, BTE enriched with TFs prevented rat hepatic fibrosis through the TGF-ß/Smad/ERK signaling pathway and kidney injury by inhibiting the expression of TGF-ß and proinflammatory cytokines in rats. We predict the broad application of TFs and related products because of their strong antioxidant and inhibitory effects on chronic inflammation.


Assuntos
Antioxidantes , Chá , Animais , Biflavonoides , Catequina , Rim , Fígado , Extratos Vegetais , Ratos
3.
J Agric Food Chem ; 69(1): 259-266, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33372513

RESUMO

Rheumatoid arthritis (RA) is an autoimmune disease characterized by long duration and repeated relapse. This study explored the preventive effect of tangeretin (TAN) and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (5-HPMF) on RA, and the underlying molecular mechanism based on a rat model stimulated by bovine type II collagen (BIIC). After the intervention of TAN or 5-HPMF (TAN/5-HPMF) for 5 weeks, the RA lesions and autophagy levels of the synovial tissue were significantly reduced, and the ROS content and HO-1 expression level were down-regulated simultaneously. The relative expression levels of p-AKT and p-mTOR were down-regulated after TAN/5-HPMF feeding. Meanwhile, the relative expression level of p62 increased by more than two-fold for TAN/5-HPMF treated rats at 200 mg/kg BW comparing with those in BIIC group. Results of immunofluorescence staining and Western blotting further confirmed that TAN/5-HPMF treatment reduced BIIC-induced conversion from LC3I to LC3II. Observations under transmission electron microscope also demonstrated that the autophagy level was reduced upon TAN/5-HPMF intervention. Collectively, these results revealed that TAN and 5-HPMF prevented the pathological process of BIIC-stimulated arthritis through inhibiting the autophagy of synovial cells, achieved via the ROS-AKT/mTOR signal axis. Thus, our findings confirmed the protective potential of TAN and 5-HPMF for RA disease.


Assuntos
Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/fisiopatologia , Flavonas/administração & dosagem , Substâncias Protetoras/administração & dosagem , Proteínas Proto-Oncogênicas c-akt/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Apoptose/efeitos dos fármacos , Artrite Reumatoide/genética , Artrite Reumatoide/metabolismo , Autofagia/efeitos dos fármacos , Bovinos , Proliferação de Células/efeitos dos fármacos , Colágeno Tipo II/efeitos adversos , Feminino , Humanos , Proteínas Proto-Oncogênicas c-akt/genética , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Membrana Sinovial/efeitos dos fármacos , Membrana Sinovial/metabolismo , Serina-Treonina Quinases TOR/genética
4.
Opt Express ; 28(11): 16594-16604, 2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-32549478

RESUMO

Highly sensitive, real-time and label-free sensing of liquid flow in microfluidic environments remains challenging. Here, by growing high-quality graphene directly on a glass substrate, we designed a microfluidic-integrated graphene-based flow sensor (GFS) capable of detecting complex, weak, and transient flow velocity and pressure signals in a microfluidic environment. This device was used to study weak and transient liquid flows, especially blood flow, which is closely related to heart and artery functions. By simulating cardiac peristalsis and arterial flow using peristaltic pumps and microfluidic systems, we monitored simulated arterial blood flow. This ultrasensitive graphene-based flow sensor accurately detected a flow velocity limit as low as 0.7 mm/s, a pumping frequency range of 0.04 Hz to 2.5 Hz, and a pressure range from 0.6 kPa to 14 kPa. By measuring the blood flow velocities and pressures, pathological blood flow signals were distinguished and captured by the corresponding flow velocities or pressures, which can reflect vascular occlusion and heart functions. This sensor may be used for the real-time and label-free monitoring of patients' basic vital signs using their blood flow and provide a possible new method for the care of critically ill patients.


Assuntos
Artérias/fisiologia , Circulação Sanguínea/fisiologia , Sistemas Computacionais , Grafite/química , Microfluídica/métodos , Coloração e Rotulagem , Simulação por Computador , Vidro/química , Coração/fisiologia , Humanos , Peristaltismo , Quartzo/química , Processamento de Sinais Assistido por Computador
5.
Sci Total Environ ; 708: 135118, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31810666

RESUMO

Arsenic (As) is an environmentally hazardous contaminant which have a serious threat to human health. In recent years, sustainability has drawn increasing attention in the environmental remediation field. Application of natural minerals as a class of iron-containing materials for soil As remediation is meaningful and challenging. In this paper the As sorption ability and soil stabilization of mechanical activated limonite has been studied. Mechanical activation can effectively enhance the adsorption performance of natural limonite. The positive effect of mechanical activation on limonite mainly include: (1) particle size reduction and specific surface area increase; (2) reduction of limonite crystallinity and increase of surface active sites; (3) mineral phase transformation to amorphous iron oxides substances. The average grain size of limonite reduces from 16.8 µm to 0.214 µm after activation while the specific surface area increases from 10.26 m2/g to 56.74 m2/g. The maximum adsorption capacities of mechanically activated limonite (Lm) for As (III) and As (V) were 9.14 mg/g and 8.26 mg/g, respectively at pH 7.0, higher than untreated limonite (L0). Mechanically activated limonite can effectively stabilize As in soils. When Lm dosage was 10%, the stabilization effects could reach about 78%. Limonite could transform the soil As from non-specifically and specifically sorbed fraction to amorphous iron hydrous oxides bounded fractions. Mechanically activated limonite (Lm) exhibited good adsorption and stabilization performance advantages for As in soils.

6.
Huan Jing Ke Xue ; 40(11): 5090-5097, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854578

RESUMO

To explore the source and pollution characteristics of soil arsenic, mineralogy and chemical analysis methods were used to analyze the ore, waste rock, sediment, and river and soil samples around the mining area. Under a polarized light microscope, As-bearing mineral-arsenopyrite was found in the soil, ore, and waste rock around the Banbishan gold mine. Moreover, arsenopyrite in the waste rock has already experienced weathering and oxidation, and the oxidized arsenopyrite easily migrates and is released in the soil, which is potentially harmful. Because of the effect of mining transportation activities and indigenous smelting, arsenic was mainly distributed in the topsoil, at a depth of 0-20 cm, in the farmland on both sides of the road and in the places where villagers were gathered. The soil arsenic content in Xiaowulan Village and Gaozhangzi Village ranged from 7.2 to 196.2 mg·kg-1 and exceeded the rate of arsenic by 45.9% and 82.1%. According to the assessment by the RAC method, the farmland soil in Xiaowulan Village and Gaozhangzi Village were mainly at low to medium risk, although some soil points in Xiaowulan Village were at high risk. In general, the effects of the mining activities of the surrounding environment were not optimistic. As-bearing minerals in the oxidation of long-term weathering can cause much arsenic to be activated, which in turn, affects the local crops and long-term residents living around the mining area. It is suggested to carry out risk assessments for arsenic in the soil-crop-atmospheric-human system, and further study the conversion rules and mechanisms of arsenopyrite during weathering, to provide scientific guidance for the environmental protection of cultivated land.

7.
Huan Jing Ke Xue ; 40(9): 4072-4080, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854870

RESUMO

Natural iron-containing minerals present in the geosphere in the form of crystalline minerals can be used as adsorption material for removal of arsenic from wastewater and remediation of arsenic-contaminated soils. In this paper, the adsorption and desorption of arsenic onto different iron-containing materials including hematite, limonite, siderite, ilmenite, magnetite, Fe2O3, Fe3O4, and Fe-Mn binary oxide (FMBO) were studied in laboratory experiments. The mechanism of arsenic adsorption was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). The results showed that arsenic adsorption is fitted by pseudo-second-order kinetics and the Langmuir isotherm model for almost all adsorbents, suggesting monolayer adsorption of arsenic onto the minerals. The sorption efficiency and capacity of arsenic by FMBO are much higher than those of other materials. Furthermore, limonite has high sorption efficiencies for both As(Ⅲ) and As(Ⅴ) among the natural iron-containing minerals, and their adsorption capacities are 3.96 mg·g-1 and 2.99 mg·g-1, respectively. The XRD results showed that natural limonite contains a large number of weak crystalline mineral components such as goethite, which can provide relatively abundant arsenic adsorption sites. Thus, limonite appears to be the most suitable natural mineral for arsenic adsorption.

8.
Nano Lett ; 18(9): 5538-5543, 2018 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-30089210

RESUMO

Optical trapping and manipulation of atoms, nanoparticles, and biological entities are widely employed in quantum technology, biophysics, and sensing. Single traps are typically achieved with linearly polarized light, while vortex beams form rotationally unstable symmetric traps. Here we demonstrate multiplexed optical traps reconfigurable with intensity and polarization of the trapping beam using intensity-dependent polarizability of nanoparticles. Nonlinearity combined with a longitudinal field of focused femtosecond vortex beams results in a stable optical force potential with multiple traps, in striking contrast to a linear trapping regime. The number of traps and their orientation can be controlled by the cylindrical vector beam order, polarization, and intensity. The nonlinear trapping demonstrated here on the example of plasmonic nanoparticles opens up opportunities for deterministic trapping and polarization-controlled manipulation of multiple dielectric and semiconductor particles, atoms, and biological objects since most of them exhibit a required intensity-dependent refractive index.

9.
Lasers Med Sci ; 33(1): 135-139, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29067617

RESUMO

According to the calculated results on the charge distribution of oxygenated heme and deoxygenated heme, and based on the theory of electron excitations in photo-acceptor molecules and the absorption spectra of hemoglobin, it is found that low-level laser within the waveband of about 800-1060 nm can promote the release of oxygen from oxyhemoglobin and improve the oxygen supply of capillaries to surrounding tissues. Furthermore, the reasons have been explained that why the low-level laser at a wavelength of 830 nm is better in the treatment on burn injury and stimulation of hair growth. We also explained why the near-infrared laser of 1064 nm is applied to the forehead to improve cerebral oxygenation in healthy humans. Finally, according to comparison of atomic charge distribution in heme before and after bound to small molecule of carbon monoxide or nitric oxide, it could be inferred that the low-level laser with an appropriate wavelength can promote the carbon monoxide hemoglobin and nitric oxide hemoglobin to dissociate the carbon monoxide molecules and the nitric oxide molecules. This may be used for adjuvant therapy of carbon monoxide poisoning or nitric oxide poisoning.


Assuntos
Hemoglobinas/metabolismo , Luz , Terapia com Luz de Baixa Intensidade , Oxigênio/metabolismo , Intoxicação por Monóxido de Carbono/radioterapia , Hemoglobina A Glicada/metabolismo , Heme/metabolismo , Humanos , Óxido Nítrico/metabolismo , Óxido Nítrico/envenenamento , Oxiemoglobinas/metabolismo , Análise Espectral
10.
Sci Rep ; 7(1): 11325, 2017 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-28900285

RESUMO

The risk factors for predicting bone metastases in patients with breast cancer are still controversial. Here, a total of 2133 patients with breast cancer, including 327 with bone metastases (15.33%) and 1806 without bone metastases (84.67%) were retrospective reviewed from January 2005 to December 2015. The spine was found to be the most common site for bone metastases, followed by ribs (57.5%), pelvis (54.1%) and sternum (44.3%). The results indicated that axillary lymph node metastases and the concentrations of CA125, CA153, ALP and hemoglobin were the independent risk factors for bone metastases in patients with breast cancer. The receiver operating characteristics (ROC) curves showed that combined axillary lymph node metastases, high CA153 and ALP, with low hemoglobin were the most accurate biomarkers for predicting bone metastases in breast cancer [area under the curve = 0.900], and the sensitivity and specificity for the prediction were 78.5% and 87.8%, respectively. Therefore, breast cancer patients with more axillary lymph node metastases, high serum concentrations of CA125, CA153, ALP and low level of hemoglobin were closely related to bone metastases. Combined axillary lymph node metastases, CA153, ALP with hemoglobin have the highest predictive accuracy for bone metastases in breast cancer.


Assuntos
Neoplasias Ósseas/epidemiologia , Neoplasias Ósseas/secundário , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/patologia , Adulto , Idoso , Neoplasias Ósseas/diagnóstico , Neoplasias da Mama/diagnóstico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Prognóstico , Curva ROC , Medição de Risco , Fatores de Risco , Tomografia Computadorizada por Raios X
11.
Nanoscale ; 9(30): 10694-10700, 2017 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-28678267

RESUMO

Intense electric fields at the nanoscale are essential for single molecule surface-enhanced Raman scattering (SERS) detection. Such fields can be achieved in plasmonic nano-gaps between nanoparticles and metal films through hybridization of surface plasmons. The nano-gaps could be formed and dynamically controlled by using plasmonic tweezers; however, the aggregation of particles in the plasmonic field degrades each particle's enhancement and spoils the nanosized-spatial resolution. Here, dual-plasmonic tweezers are proposed and demonstrated to accurately control the number of nano-gaps and enhancement by tailoring a crater-shaped potential well in the nano-trap system. As the electric field in the nano-gap is intense, SERS spectral signatures of a single molecular level are probed simultaneously. These advantages point towards the implementation of enhanced Raman spectra, and broad applications in optical molecular detection.

12.
Nanoscale ; 8(18): 9756-63, 2016 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-27117313

RESUMO

In general, when a semiconductor nanowire is trapped by conventional laser beam tweezers, it tends to be aligned with the trapping beam axis rather than confined in the horizontal plane, and this limits the application of these nanowires in many in-plane nanoscale optoelectronic devices. In this work, we achieve the in-plane trapping and manipulation of a single ZnO nanowire by a hybrid plasmonic tweezer system on a flat metal surface. The gap between the nanowire and the metallic substrate leads to an enhanced gradient force caused by deep subwavelength optical energy confinement. As a result, the nanowire can be securely trapped in-plane at the center of the excited surface plasmon polariton field, and can also be dynamically moved and rotated by varying the position and polarization direction of the incident laser beam, which cannot be performed using conventional optical tweezers. The theoretical results show that the focused plasmonic field induces a strong in-plane trapping force and a high rotational torque on the nanowire, while the focused optical field produces a vertical trapping force to produce the upright alignment of the nanowire; this is in good agreement with the experimental results. Finally, some typical ZnO nanowire structures are built based on this technique, which thus further confirms the potential of this method for precise manipulation of components during the production of nanoelectronic and nanophotonic devices.

13.
Sci Rep ; 5: 15446, 2015 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-26481689

RESUMO

Typically, metal particles are difficult to manipulate with conventional optical vortex (OV) tweezers, because of their strong absorption and scattering. However, it has been shown that the vortex field of surface plasmonic polaritons, called plasmonic vortex (PV), is capable of stable trapping and dynamic rotation of metal particles, especially those of mesoscopic and Mie size. To uncover the different physical mechanisms of OV and PV tweezers, we investigated the force distribution and trapping potential of metal particles. In OV tweezers the stronger scattering force causes a positive potential barrier that repels particles, whereas in PV tweezers the dominant gradient force contributes to a negative potential well, resulting in stably trapped particles. Compared with OV, the orbital angular momentum of PV produces an azimuthal scattering force that rotates the trapped particles with more precise radius and position. Our results demonstrate that PV tweezers are superior in manipulation of metal particles.

14.
Nano Lett ; 14(11): 6430-6, 2014 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-25302534

RESUMO

Hybridization in the narrow gaps between the surface plasmon polaritons (SPPs) along a metal surface and the localized surface plasmons on metallic nano-objects strongly enhance the electromagnetic field. Here, we employ plasmonic hybridization to achieve dynamic trapping and manipulation of a single metallic nanowire on a flat metal surface. We reveal that the plasmonic hybridization achieved by exciting plasmonic tweezers with a linearly polarized laser beam could induce strong trapping forces and large rotational torques on a single metallic nanowire. The position and orientation of the nanowire could dynamically be controlled by the hybridization-enhanced nonisotropic electric field in the gap. Experimental results further verify that a single Au nanowire could robustly be trapped at the center of an excited SPP field by the induced forces and then rotated by the torques. Finally, a plasmonic swallow tail structure is built to demonstrate its potential in the fabrication of lab-on-a-chip plasmonic devices.

15.
Nat Commun ; 4: 2891, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24305554

RESUMO

Scattering forces in focused light beams push away metallic particles. Thus, trapping metallic particles with conventional optical tweezers, especially those of Mie particle size, is difficult. Here we investigate a mechanism by which metallic particles are attracted and trapped by plasmonic tweezers when surface plasmons are excited and focused by a radially polarized beam in a high-numerical-aperture microscopic configuration. This contrasts the repulsion exerted in optical tweezers with the same configuration. We believe that different types of forces exerted on particles are responsible for this contrary trapping behaviour. Further, trapping with plasmonic tweezers is found not to be due to a gradient force balancing an opposing scattering force but results from the sum of both gradient and scattering forces acting in the same direction established by the strong coupling between the metallic particle and the highly focused plasmonic field. Theoretical analysis and simulations yield good agreement with experimental results.

16.
J Phys Chem B ; 111(34): 10160-5, 2007 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-17683135

RESUMO

The conformational and dynamic properties of 1-octanol in neat and in water-saturated states have been investigated by 1H NMR. It has been proved that neat 1-octanol is microheterogeneous in nature comprising regions enriched in either hydrocarbons or hydroxyl groups. A reversed micelle-like cluster model was proposed, where the octanol cluster has an inner polar core of hydrogen-bonded octanol hydroxyls and an outer shell of nonpolar alkyl chains radiating outside. It was also observed that the cluster structure of octanol experiences minor changes with the presence of water. In water-saturated octanol, water molecules associate via hydrogen bonding and reside in the innermost center of the polar region with restricted motion, whereas the octanol cluster structure is modified by loosening the compact structure. Moreover, the preferential solvations of both systems were tested and compared. It not only gives some clues about the microheterogeneity of the alcohol system and the structure of the cluster but also helps in advancing our understanding on the behavior and properties of the amphiphilic molecules system such as phospholipids.

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