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1.
Nanomaterials (Basel) ; 9(8)2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31349620

RESUMO

We present a theoretical study on the adsorption and spin transport properties of magnetic Fe@C28 using Ab initio calculations based on spin density functional theory and non-equilibrium Green's function techniques. Fe@C28 tends to adsorb on the bridge sites in the manner of C-C bonds, and the spin-resolved transmission spectra of Fe@C28 molecular junctions exhibit robust transport spin polarization (TSP). Under small bias voltage, the transport properties of Fe@C28 are mainly determined by the spin-down channel and exhibit a large spin polarization. When compressing the right electrode, the TSP is decreased, but high spin filter efficiency (SFE) is still maintained. These theoretical results indicate that Fe@C28 with a large magnetic moment has potential applications in molecular spintronics.

2.
J Biomater Sci Polym Ed ; 29(15): 1825-1838, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30067142

RESUMO

Polymeric porous ultrafine fibers with different structures as drug carrier could be facilely prepared. However, the drug release characteristics and relevant mechanism of different structural porous ultrafine fibers were not well studied. In the present work, different structural Poly-Ether-Sulfone (PES) based porous ultrafine fibers, namely PES, PES/Poly-Ethylene-Glycol (PEG) and PES/Water were prepared by electro-spinning. Curcumin was chosen as drug model loaded in these fibers. Investigation of curcumin release characteristics was carried out by the total immersion in buffer solution. The surface and inner structure of PES based ultrafine fibers were studied by scanning electron microscopy (SEM) in detail. It is found that there is significant difference in the accumulate release amount and release rate with similar structure. About 92.5% of curcumin released within 600 min for PES/PEG ultrafine fibers and only 58.9% of curcumin flowed out from PES with 1000 min. In order to discuss the fact of this phenomenon, the development structure of PES based porous ultrafine fibers was studied with curcumin release. The results indicated that the curcumin release was directly involved with the structure. For PES/PEG, curcumin around the surface layer released in advance. And then, some penetrable structure emerged with PEG dissolving in the buffer solution, which result in larger specific surface area and more embedded curcumin from the interior structure of the ultrafine fibers diffusing out. For the others, curcumin release only through its own pores of ultrafine fibers. Finally, the processing-structure-performance relationship of PES based porous ultrafine fibers were confirmed by the diversity of porosity and contact angle. The research results demonstrate that PES based porous ultrafine fibers have the potential to be used as drug carrier in the drug delivery according to the practical clinical requirements.


Assuntos
Curcumina/administração & dosagem , Portadores de Fármacos/química , Polímeros/química , Sulfonas/química , Liberação Controlada de Fármacos , Cinética , Polietilenoglicóis/química , Porosidade , Propriedades de Superfície , Água
3.
Oncol Lett ; 13(2): 973-978, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28356987

RESUMO

Corn silk is an economically and nutritionally significant natural product as it represents a staple food for a large proportion of the world population. This study investigated the anticancer activity of corn silk extract in human colon cancer cells and human gastric cancer cells. Following treatment with corn silk extract, certain apoptosis-related events were observed, including inhibition of cell proliferation, loss of mitochondrial membrane potential (ΔΨm), release of Ca2+ and release of cytochrome c from the mitochondria into the cytosol. Our results revealed that corn silk extract inhibited the proliferation of cancer cells and increased the level of apoptosis in a concentration-dependent manner. Western blot analysis revealed that corn silk extract upregulated the levels of Bax, cytochrome c, caspase-3 and caspase-9, but downregulated the levels of B-cell lymphoma 2. These results suggest that corn silk extract may induce apoptosis through the mitochondria-mediated pathway.

5.
J Colloid Interface Sci ; 424: 49-55, 2014 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-24767497

RESUMO

A simple and practical strategy has been developed for preparing polyaniline (PANi) coated TiO2/SiO2 nanofiber membranes by a combination of electrospinning, calcination and in situ polymerization. TiO2/SiO2 (TS) nanofibers are fabricated by electrospinning, followed by calcination. Then they are used as template for in situ polymerization of aniline monomers. SEM images show that PANi nanoparticles thus formed can be densely and uniformly coated on the surface of TS nanofibers. Photocatalytic degradation tests show that the as-prepared nanofiber membranes exhibit enhanced photocatalytic activity for degradation of methyl orange under visible light, which may be due to the synergistic effect of PANi and TiO2. Furthermore, the effect of polymerization time on the morphology and photocatalytic activity of the membrane is investigated. The free-standing membrane is flexible and easy to handle, which is promising for potential applications in photocatalysis and water remediation fields.

6.
Autophagy ; 10(5): 736-49, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24642486

RESUMO

Metabolic stress induces autophagy as an alternative source of energy and metabolites. Insufficient autophagy in nutrient-deprived cancer cells would be beneficial for cancer therapy. Here, we performed a functional screen in search of novel autophagy regulators from natural products. We showed that oblongifolin C (OC), a natural small molecule compound extracted from Garcinia yunnanensis Hu, is a potent autophagic flux inhibitor. Exposure to OC results in an increased number of autophagosomes and impaired degradation of SQSTM1/p62. Costaining of GFP-LC3B with LysoTracker Red or LAMP1 antibody demonstrates that autophagosome-lysosome fusion is blocked by OC treatment. Furthermore, OC inhibits lysosomal proteolytic activity by altering lysosomal acidification and downregulating the expression of lysosomal cathepsins. Importantly, OC can eliminate the tolerance of cancer cells to nutrient starvation. Starvation dramatically increases the susceptibility of cancer cells to OC-induced CASP3-dependent apoptosis in vitro. Subsequent studies in xenograft mouse model showed that OC has anticancer potency as revealed by increased staining of cleaved CASP3, LC3 puncta, and SQSTM1, as well as reduced expression of lysosomal cathepsins. Combined treatment with OC and caloric restriction potentiates anticancer efficacy of OC in vivo. Collectively, these data demonstrated that OC is a novel autophagic flux inhibitor and might be useful in anticancer therapy.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Autofagia/efeitos dos fármacos , Privação de Alimentos/fisiologia , Terpenos/farmacologia , Animais , Células Cultivadas , Ensaios de Seleção de Medicamentos Antitumorais , Alimentos , Células HCT116 , Células HeLa , Células Hep G2 , Humanos , Células MCF-7 , Camundongos , Resultado do Tratamento
7.
Autophagy ; 10(1): 70-9, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24262949

RESUMO

Hypoxia activates autophagy, an evolutionarily conserved cellular catabolic process. Dysfunction in the autophagy pathway has been implicated in an increasing number of human diseases, including cancer. Hypoxia induces upregulation of a specific set of microRNAs (miRNAs) in a variety of cell types. Here, we describe hypoxia-induced MIR155 as a potent inducer of autophagy. Enforced expression of MIR155 increases autophagic activity in human nasopharyngeal cancer and cervical cancer cells. Knocking down endogenous MIR155 inhibits hypoxia-induced autophagy. We demonstrated that MIR155 targets multiple players in MTOR signaling, including RHEB, RICTOR, and RPS6KB2. MIR155 suppresses target-gene expression by directly interacting with their 3' untranslated regions (UTRs), mutations of the binding sites abolish their MIR155 responsiveness. Furthermore, by downregulating MTOR signaling, MIR155 also attenuates cell proliferation and induces G 1/S cell cycle arrest. Collectively, these data present a new role for MIR155 as a key regulator of autophagy via dysregulation of MTOR pathway.


Assuntos
Autofagia/genética , MicroRNAs/genética , Transdução de Sinais/genética , Serina-Treonina Quinases TOR/metabolismo , Regiões 3' não Traduzidas/genética , Sequência de Bases , Ciclo Celular/genética , Hipóxia Celular/genética , Linhagem Celular Tumoral , Proliferação de Células , Regulação para Baixo/genética , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , MicroRNAs/metabolismo , Dados de Sequência Molecular , Proteínas de Neoplasias/metabolismo , Fagossomos/metabolismo , Regulação para Cima/genética
8.
Zhonghua Liu Xing Bing Xue Za Zhi ; 35(12): 1375-8, 2014 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-25623458

RESUMO

OBJECTIVE: To describe the molecular characteristics of group A Streptococcus (GAS) isolated from patients and asymptomatic carriers of scarlet fever in Shandong province, 2013, and to explore the relationships between emm types and other molecular types. METHODS: 72 strains of GAS were isolated from throat swabs of children with scarlet fever or asymptomatic carriers of GAS. All the strains were typed by emm typing, multilocus sequence typing (MLST), super-antigen (SAg) genes detections and pulsed-field gel electrophoreses (PFGE). RESULTS: Among the 72 strains, emm1 (41.67%) and emm12 (56.94%) were the most common emm types. Two ST types were found, including ST28 (43.06%) and ST36 (56.94%). Additionally, emm1 was also found correlated to ST28, while emm12 was associated with ST36. Eight super-antigen genes were detected, including smeZ (100.00%), ssa (100.00%), speG (97.22%), speC (95.83%), speL (54.17%), speJ (41.67%), speA (38.89%) and speH (38.89%), while speK, speM, speL were not found (0%). Both speA and speJ genes were detected primarily in emm1 strains (all P < 0.05), while speH and speI genes were not detected in emm 1 strains (all P < 0.05). And emm12 strains were inclined to harbor speH and speL (all P < 0.05) but not speA or speJ (all P < 0.05). Twenty different genotypes were identified by PFGE. CONCLUSION: All the emm types of GAS isolated from scarlet fever patients and asymptomatic carriers in Shandong province 2013 were mainly emm1 and emm12 and carrying speC, speG and smeZ, ssa. ST types mainly exsited in ST28 and ST36. In addition, there were correlations between emm types and super-antigen genes, ST types, PFGE types.


Assuntos
Escarlatina/microbiologia , Streptococcus pyogenes/genética , Antígenos de Bactérias , Proteínas de Bactérias , Criança , Eletroforese em Gel de Campo Pulsado , Exotoxinas , Genótipo , Humanos , Proteínas de Membrana , Tipagem de Sequências Multilocus , Streptococcus pyogenes/isolamento & purificação
9.
ACS Appl Mater Interfaces ; 5(15): 7584-91, 2013 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-23855959

RESUMO

Ni-doped graphene/carbon cryogels (NGCC) have been prepared by adding resorcinol and formaldehyde to suspension of graphene oxide (GO), using Ni(2+) ions as catalysts for the gelation process to substitute the usually used alkaline carbonates. The metal ions of Ni(2+) have elevated the cross-linking between GO and RF skeletons, thus strengthening the whole cryogel. The as-formed three-dimensional (3D) interconnected structures, which can be well-maintained after freeze-drying of the hydrogel precursor and subsequent carbonization under an inert atmosphere, exhibit good mechanical properties. During the carbonization process, Ni(2+) ions are converted into Ni nanoparticles and thus embedded in the interconnected structures. The unique porosity within the interconnected structures endows the cryogels with good capability for the extraction of oils and some organic solvents while the bulk form enables its recycling use. When ground into powders, they can be used as adsorbents for dyestuffs. Therefore, the as-obtained cryogels may find potential applications as versatile candidates for the removal of pollutants from water.


Assuntos
Carbono/química , Criogéis/química , Grafite/química , Níquel/química , Purificação da Água/instrumentação , Purificação da Água/métodos , Adsorção , Corantes/química , Formaldeído/química , Hidrogéis/química , Microscopia Eletrônica de Varredura/métodos , Óleos/química , Óxidos/química , Resorcinóis/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Estresse Mecânico , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
10.
ACS Appl Mater Interfaces ; 4(10): 5353-9, 2012 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-22974085

RESUMO

Hierarchical SiO(2)@γ-AlOOH (Boehmite) core/sheath fibers are fabricated based on a combination of electrospinning and hydrothermal reaction. γ-AlOOH (Boehmite) nanoplatelets are uniformly anchored on the surface of SiO(2) fibers, which significantly improves the adsorption efficiency of the SiO(2) fiber membrane for organic dyes and microorganisms. Compared to conventional nanoparticle adsorbents, the self-standing membrane thus prepared is highly flexible and easy to handle and retrieve, making it a promising material for water treatment. By virtue of electrospinning and a hydrothermal reaction, it provides possibilities to fabricate other functional fiber membranes with hierarchical structures, which can find potential applications in adsorption, catalysis, filtration, and other environmental remediation fields.

11.
Int J Oncol ; 23(2): 353-61, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12851684

RESUMO

Astrocytomas are very common intracranial glial cell neoplasms with an inherent tendency to progress. However, the heterogeneity of the morphological features and clinical behavior of the tumors makes accurate prognosis based on the histopathological grading system very difficult. Studies demonstrated that astrocytes have two distinctive cell lineages, and tumors arisen from these two astrocytic lineages have been speculated to have different biological and clinical manifestations. The present study aimed to delineate these two astrocytic lineages in human astrocytomas by using different immunohistochemical markers and to correlate the cell lineages of the tumors with their recurrence. Three markers were used, namely the A2B5 antigen, which is present in type 2 astrocytes but absent in type 1 astrocytes, glial fibrillary acidic protein (GFAP), a marker for astrocytes, and galactocerebroside (GC), a marker for oligodendrocytes. It was found that astrocytomas sharing the A2B5+ lineage (A2B5 positive and GFAP positive) have a significantly higher recurrence rate than the tumors of the A2B5- lineage (A2B5 negative and GFAP positive). Immunohistochemical staining and PCR-single-stranded conformational polymorphism analysis showed that p53 overexpression and p53 mutations were closely associated with the recurrent astrocytomas, and p53 abnormalities were more frequently detected in astrocytomas of the A2B5+ lineage. Quantification of proliferation by counting argyrophil nucleolar organizer regions (AgNORs) indicated a higher AgNOR count in the A2B5+ lineage than the A2B5- lineage. Our findings thus suggest that astrocytomas share similar antigenicity with astrocytes, and that the A2B5+ lineage exhibited a higher recurrence rate than the A2B5- lineage. The higher recurrence rate of the A2B5+ tumors may be in part related to the higher frequency of p53 abnormalities found in the tumors and the higher proliferative activity as reflected by the higher AgNOR count of the tumors.


Assuntos
Antígenos de Neoplasias/metabolismo , Astrocitoma/classificação , Neoplasias Encefálicas/classificação , Linhagem da Célula , Recidiva Local de Neoplasia/patologia , Astrocitoma/metabolismo , Astrocitoma/patologia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Divisão Celular , Galactosilceramidas/metabolismo , Gangliosídeos/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Técnicas Imunoenzimáticas , Região Organizadora do Nucléolo/metabolismo , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Prata , Proteína Supressora de Tumor p53/metabolismo
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