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1.
Phys Rev Lett ; 124(3): 036803, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-32031860

RESUMO

Current understanding of higher-order topological insulators (HOTIs) is based primarily on crystalline materials. Here, we propose that HOTIs can be realized in quasicrystals. Specifically, we show that two distinct types of second-order topological insulators (SOTIs) can be constructed on the quasicrystalline lattices (QLs) with different tiling patterns. One is derived by using a Wilson mass term to gap out the edge states of the quantum spin Hall insulator on QLs. The other is the quasicrystalline quadrupole insulator (QI) with a quantized quadrupole moment. We reveal some unusual features of the corner states (CSs) in the quasicrystalline SOTIs. We also show that the quasicrystalline QI can be simulated by a designed electrical circuit, where the CSs can be identified by measuring the impedance resonance peak. Our findings not only extend the concept of HOTIs into quasicrystals but also provide a feasible way to detect the topological property of quasicrystals in experiments.

2.
EBioMedicine ; 51: 102583, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31901866

RESUMO

BACKGROUND: Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 is an important RNA-binding protein that affects the RNA processing, splicing, transport and stability of many genes. hnRNPA2/B1 is expressed during proliferation and metastasis of various cancer types and promotes such processes. However, the precise role and mechanism of hnRNPA2/B1 in breast cancer remain unclear. METHODS: The association of hnRNPA2/B1 with breast cancer metastasis was assessed using tissue chips, mouse models and publicly available data. The role and mechanism of hnRNPA2/B1 in breast cancer metastasis were studied in cell lines and mouse models. FINDINGS: In contrast to other cancer research findings, hnRNPA2/B1 expression was negatively correlated with breast cancer metastasis. hnRNPA2/B1 inhibited MDA-MB-231 triple-negative breast cancer (TNBC) cell metastasis in vitro and in vivo. hnRNPA2/B1 knockout activated ERK-MAPK/Twist and GR-beta/TCF4 pathways but inhibited STAT3 and WNT/TCF4 signalling pathways. Profilin 2 (PFN2) promoted breast cancer cell migration and invasion, whereas hnRNPA2/B1 bound directly to the UAGGG locus in the 3'-untranslated region of PFN2 mRNA and reduced the stability of PFN2 mRNA. INTERPRETATION: Our data supported the role of hnRNPA2/B1 in tumour metastasis risk and survival prediction in patients with breast cancer. The inhibitory role of hnRNPA2/B1 in metastasis was a balance of downstream multiple genes and signalling pathways. PFN2 downregulation by hnRNPA2/B1 might partly explain the inhibitory mechanism of hnRNPA2/B1 in breast cancer metastasis. Therefore, hnRNPA2/B1 might be used as a new prognostic biomarker and valuable molecular target for breast cancer treatments.

3.
Exp Cell Res ; 387(1): 111752, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31805277

RESUMO

MicroRNA-501-3p (miR-501-3p) has been reported to play tumor-suppressive roles in different cancers; however, its expression pattern and biological function in non-small cell lung cancer (NSCLC) remain unknown. In this study, we noted downregulation of miR-501-3p in NSCLC tissues and cell lines. Functional assays showed that overexpression of miR-501-3p suppressed NSCLC cell proliferation, clonogenicity, migration, and invasion. Moreover, miR-501-3p overexpression attenuated in vivo tumor growth in a nude mouse model. In terms of the mechanism, RAP1A was identified as a novel target of miR-501-3p. Overexpression of RAP1A strongly attenuated the inhibitory effects of miR-501-3p on the capacity of NSCLC cells for proliferation and motility. In the clinical samples of NSCLC, miR-501-3p levels negatively correlated with RAP1A expression, which was upregulated in NSCLC. Collectively, these results indicate that miR-501-3p acts as a tumor suppressor in NSCLC by directly targeting RAP1A mRNA and may serve as a theranostic biomarker for patients with NSCLC.

4.
Artif Cells Nanomed Biotechnol ; 48(1): 188-196, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31865777

RESUMO

Background: Glioblastoma multiforme (GBM) is one of the most prevailing primary brain tumours among adults and most aggressive cancers. Despite multiple developments in medical and surgical treatments, GBM is still a deadly disease with a high mortality rate. Here, this study was performed to investigate the function of circPVT1 on GBM.Methods: CCK-8 and flow cytometry were utilised to estimate viability and apoptosis in both cells. qRT-PCR was performed to determine circPVT1 and miR-199a-5p expression. Western blot was conducted to determine apoptosis, migration and EMT-related proteins levels when silencing circPVT1. Subsequently, these parameters were re-tested after up-regulating miR-199a-5p.Results: CircPVT1 was highly expressed in GBM tissues. Silencing circPVT1 raised two cells apoptosis and reduced viability and migration capacity. Moreover, EGF-induced EMT was repressed by silencing circPVT1. In addition, miR-199a-5p expression was elevated when silencing circPVT1. And silencing circPVT1 exerted above changes via up-regulating miR-199a-5p. Finally, silencing circPVT1 repressed YAP1 and PI3K/AKT pathways via up-regulating miR-199a-5p.Conclusion: Our data suggested that silencing circPVT1 inhibited viability, migration, EGF-induced EMT and promoted apoptosis as well as repressed YAP1 and PI3K/AKT pathways by up-regulating miR-199a-5p.HIGHLIGHTSCircPVT1 expression is highly expressed in GBM tissues;Si-circPVT1 represses migration and promoted apoptosis in U539 and U251 cells;Si-circPVT1 represses migration and promoted apoptosis when elevating miR-199a-5p;Si-circPVT1 represses EGF-induced EMT when increasing miR-199a-5p;Si-circPVT1 suppresses YAP1 and PI3K/AKT pathways by up-regulating miR-199-5p.

5.
Artigo em Inglês | MEDLINE | ID: mdl-31767359

RESUMO

OBJECTIVE: To investigate a technical method for harvesting and using the descending branch of the lateral circumflex femoral artery (DLCFA) in coronary artery bypass grafting (CABG). METHODS: Between January 2017 and January 2019, 40 patients (36 in the planed selection group and 4 in the temporary decision group) with mean age of 49.1 ± 7.5 years received DLCFA as an arterial conduit in CABG. In all patients, the DLCFA was successfully harvested via an anterior thigh incision. Depending on the location of the target vessel, the DLCFA was used as a free graft or a composite graft. RESULTS: Of the 44 patients in the planned selection group, DLCFA harvesting was abandoned in 8 patients because computed tomographic angiography revealed anatomical variation or stenosis of the superficial femoral artery. Of the 5 patients in the temporary decision group, harvesting was abandoned in 1 because of short length and thin caliber. On an average, 3.7 ± 0.9 distal anastomoses were created during CABG, with no adverse effects. The length of the harvested DLCFA was 9.9 ± 1.7 cm, with an average proximal lumen diameter of 3.4 ± 0.7 mm. The DLCFA was used as a free graft in 26 patients and as a "Y"-shape composite graft in 14 patients. Total arterial CABG was performed in 75% of the patients. CONCLUSIONS: The DLCFA is an alternative conduit for CABG. It can be harvested easily and safely. However, preoperative computed tomographic angiography examination is necessary for the smooth application of the DLCFA, and an appropriate strategy for graft establishment should be considered.

6.
Molecules ; 24(22)2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31703405

RESUMO

A simple, sensitive and effective magnetic solid-phase extraction (MSPE) technique was developed for the extraction of pyrethroid pesticides from environmental water samples, followed by gas chromatography tandem triple quadrupole mass spectrometry determination. An adsorbent of magnetic zeolitic imidazolate framework-8@deep eutectic solvent (M-ZIF-8@DES) was prepared using deep eutectic solvent coated on the surface of M-ZIF-8. The features of M-ZIF-8@DES were confirmed by material characterizations, and the results indicated that M-ZIF-8@DES has a good magnetism (61.3 emu g-1), a decent surface area (96.83 m2 g-1) and pore volume (0.292 mL g-1). Single factor experiments were carried out to investigate the effect of different conditions on the performance of MSPE. Under the optimal conditions, the developed method performs good linearity (R2 ≥ 0.9916) in the concentration range of 1-500 µg L-1. The limits of detection were in the range of 0.05-0.21 µg L-1 (signal/noise = 3/1). The intraday relative standard deviation (RSD) and interday RSD were less than 9.40%. Finally, the proposed technique was applied for the determination of pyrethroid pesticides in environmental water samples. This work shows the potential of DES-modified metal-organic frameworks for different sample pretreatment techniques.

7.
Pharmacol Res ; 150: 104454, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31526871

RESUMO

Zinc(II) complexes of curcumin display moderate cytotoxicity towards cancer cells at low micromolar concentrations. However, the clinical use of zinc(II) complexes is hampered by hydrolytic insolubility and poor bioavailability and their anticancer mechanisms remain unclear. Here, we investigated the efficacy and mechanism of action of a polyvinylpyrrolidone (PVP-k30)-based solid dispersion of Zn(II)-curcumin (ZnCM-SD) against hepatocellular carcinoma (HCC) in vitro and in vivo. In vitro assays revealed ZnCM-SD not only reduced the viability of HepG2 cells and SK-HEP1 cells in a dose-dependent manner, but also potently and synergistically enhanced cell growth inhibition and cell death in response to doxorubicin by regulating cellular zinc homeostasis. ZnCM-SD was internalized into the cells via non-specific endocytosis and degraded to release curcumin and Zn2+ ions within cells. The anticancer effects also occur in vivo in animals following the oral administration of ZnCM-SD, without significantly affecting the weight of the animals. Interestingly, ZnCM-SD did not reduce tumor growth or affect zinc homeostasis in HepG2-bearing mice after gut microbiome depletion. Moreover, administration of ZnCM-SD alone or in combination with doxorubicin significantly attenuated gut dysbiosis and zinc dyshomeostasis in a rat HCC model. Notably, fecal microbiota transplantation revealed the ability of ZnCM-SD to regulate zinc homeostasis and act as a chemosensitizer for doxorubicin were dependent on the gut microbiota. The crucial role of the gut microbiota in the chemosensitizing ability of ZnCM-SD was confirmed by broad-spectrum antibiotic treatment. Collectively, ZnCM-SD could represent a simple, well-tolerated, safe, effective therapy and function as a novel chemosensitizing agent for cancer.

8.
Crit Rev Anal Chem ; : 1-13, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31423806

RESUMO

Developing a rapid sample pretreatment method with high enrichment capability and selectivity is important for developing novel analytical techniques in food and environmental safety monitoring. Metal-organic frameworks (MOFs) are multifunctional three-dimensional materials that can be self-assembly prepared from organic ligands and inorganic metal ions or a metal cluster. MOFs have high specific surface areas, good adsorption performance, tunable porosity, and modifiable structures that can be deliberately modulated. They have been widely applied in photoelectrocatalysis, adsorption/separation, drug delivery, sensor detection, and more, because of their superparamagnetism, rapid adsorption/separation, and reusability. As effective adsorbents, magnetic MOFs (MMOFs) have attracted enomous attentions in analytical chemistry and have been used in sample collection and pre-enrichment, solid-phase extraction, and solid-phase microextraction in recent years. In this review, we summarize recent developments in the preparation of MMOFs, understanding of their structural characteristics and adsorption mechanisms, and their applications in food quality/safety and pretreatment. Future prospects in research and development are also discussed.

9.
Ecotoxicol Environ Saf ; 183: 109546, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31437727

RESUMO

A ß-cyclodextrin-functionalized magnetic zinc-metal organic framework (M-MOF/ß-CD) was synthesized via a facile one-pot reaction. M-MOF/ß-CD was used as a magnetic porous absorbent for the extraction and determination of prochloraz and three triazole fungicides in vegetable samples. M-MOF/ß-CD was prepared by creating MOF layers on the surface of a Fe3O4-graphene oxide (GO) nanocomposite and bonding them with ß-CD molecules. Characterization suggested that a 3D porous structure was formed, with M-MOF/ß-CD exhibiting high superparamagnetism and a large surface area. As a new strategy, integrating MOFs with Fe3O4-GO could improve their water-resistance and mechanical strength by providing a rigid nanosupport interface. Combining M-MOF and ß-CD resulted in excellent selective adsorption capacities for prochloraz and three triazole fungicides. The static adsorption process was evaluated and the results were in good agreement with the Freundlich model. Subsequently, M-MOF/ß-CD was applied to extracting prochloraz and triazole fungicides from tomato and lettuce vegetables, followed by HPLC-MS/MS determination. The limits of detection for the above fungicides were found to be 0.25-1.0 µg/L at a signal-to-noise ratio of 3, with spiked recoveries of 74.13%-119.83%, indicating that M-MOF/ß-CD was promising for application to the extraction and determination of fungicides in complex matrices.


Assuntos
Fungicidas Industriais/análise , Imidazóis/análise , Nanopartículas de Magnetita/química , Estruturas Metalorgânicas/química , Triazóis/análise , Verduras/química , beta-Ciclodextrinas/química , Adsorção , Grafite/química , Limite de Detecção , Nanocompostos/química , Porosidade , Reprodutibilidade dos Testes , Propriedades de Superfície
10.
Food Funct ; 10(9): 5587-5604, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31432062

RESUMO

Doxorubicin is a powerful anticancer agent used to treat a variety of human neoplasms. However, the clinical use of doxorubicin is hampered by cardiotoxicity and effective cardioprotective adjuvants do not exist. Dietary zinc, an essential nutrient, is required to maintain steady-state tissue zinc levels and intestinal homeostasis and may yield therapeutic benefits in diseases associated with zinc dysregulation or gut dysbiosis. Here, we investigated the effects of dietary Zn(ii)-curcumin (ZnCM) solid dispersions on gut dysbiosis and zinc dyshomeostasis during doxorubicin-induced cardiotoxicity in rats. Rats were injected with multiple low doses of doxorubicin and orally administered ZnCM daily over four weeks. Daily administration of ZnCM not only alleviated Dox-induced gut dysbiosis-as indicated by the increased Firmicutes-to-Bacteroidetes ratio and the maintenance of the relative abundances of major beneficial bacteria including Clostridium_XIVa, Clostridium_IV, Roseburia, Butyricicoccus and Akkermansia-but also maintained intestinal barrier integrity and decreased the lipopolysaccharide (LPS) contents of feces and plasma. ZnCM also significantly attenuated doxorubicin-induced zinc dyshomeostasis, which was mirrored by preservation of zinc levels and expression of zinc-related transporters. Furthermore, ZnCM significantly improved heart function and reduced cardiomyocyte apoptosis and myocardial injury in doxorubicin-treated rats. Notably, the regulation of zinc homeostasis and cardioprotective and microbiota-modulating effects of ZnCM were transmissible through horizontal feces transfer from ZnCM-treated rats to normal rats. Thus, ZnCM supplementation has potential as an effective therapeutic strategy to alleviate gut dysbiosis and zinc dyshomeostasis during doxorubicin-induced cardiotoxicity.

11.
Molecules ; 24(15)2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31362458

RESUMO

As persistent organic pollutants, dichlorodiphenyltrichloroethanes (DDTs) and their metabolites pose considerable risks to human health and the environment. Therefore, monitoring DDTs in the environment is essential. Here, we developed a green, simple, and effective magnetic solid-phase extraction (MSPE) method coupled with gas chromatography tandem triple-quadrupole mass spectrometry to determine the DDT content of environmental water samples. A magnetic ionic liquid (IL) adsorbent was developed based on a modified magnetic multiwalled carbon nanotube/zeolitic imidazolate framework-8 (MM/ZIF-8/IL), synthesized by immobilizing the IL on the surface of MM/ZIF-8. We confirmed successful synthesis of MM/ZIF-8/IL by material characterization, and our results suggested that the MM/ZIF-8/IL had a high Brunauer-Emmett-Teller surface area (159.9 m2 g-1), good thermostability (<800 °C), and a high degree of superparamagnetism (52.9 emu g-1). Several experimental conditions affecting the MSPE efficiency were optimized. Under the best conditions, good detection linearity was achieved (0.5-500 µg L-1) with determination coefficients ranging from 0.9927 to 0.9971. The lower limits of detection (0.0016-0.0072 µg L-1) also had good precision, having an intraday relative standard deviation (RSD) ≤ 6.5% and an interday RSD ≤ 8.9%. Finally, we used the as-developed method to determine DDT levels in environmental water samples.


Assuntos
DDT/química , DDT/isolamento & purificação , Líquidos Iônicos , Magnetismo , Nanotubos de Carbono , Extração em Fase Sólida , Poluentes Químicos da Água , Nanotubos de Carbono/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Zeolitas/química
12.
Nanomaterials (Basel) ; 9(7)2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31323858

RESUMO

Molecular imprinting technology (MIT), also known as molecular template technology, is a new technology involving material chemistry, polymer chemistry, biochemistry, and other multi-disciplinary approaches. This technology is used to realize the unique recognition ability of three-dimensional crosslinked polymers, called the molecularly imprinted polymers (MIPs). MIPs demonstrate a wide range of applicability, good plasticity, stability, and high selectivity, and their internal recognition sites can be selectively combined with template molecules to achieve selective recognition. A molecularly imprinted fluorescence sensor (MIFs) incorporates fluorescent materials (fluorescein or fluorescent nanoparticles) into a molecularly imprinted polymer synthesis system and transforms the binding sites between target molecules and molecularly imprinted materials into readable fluorescence signals. This sensor demonstrates the advantages of high sensitivity and selectivity of fluorescence detection. Molecularly imprinted materials demonstrate considerable research significance and broad application prospects. They are a research hotspot in the field of food and environment safety sensing analysis. In this study, the progress in the construction and application of MIFs was reviewed with emphasis on the preparation principle, detection methods, and molecular recognition mechanism. The applications of MIFs in food and environment safety detection in recent years were summarized, and the research trends and development prospects of MIFs were discussed.

13.
Sci Rep ; 9(1): 8919, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222032

RESUMO

A magnetic graphene/polydopamine (MG/PDA) nanocomposite has been prepared and used as sorbent for magnetic dispersive solid-phase extraction (MDSPE) of four benzoylurea insecticides in environmental water samples. The obtained nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, powder X-ray diffraction, fourier transform infrared spectroscopy, surface area and porosity analysis and thermogravimetric analysis. To investigate the adsorption performance of MG/PDA for target analytes, various parameters affecting the MG/PDA-based MDSPE procedure were optimized. Under the optimal conditions, the established method exhibits good linearity (R2 ≥ 0.9988) in the concentration range 2.5-500 µg L-1. A low limit of detection (0.75 µg L-1, signal/noise = 3:1), a low limit of quantification (2.50 µg L-1, signal/noise = 10:1), and good precision (intraday relative standard deviation ≤3.6%, interday relative standard deviation ≤4.5%) are also achieved. Finally, the simple, fast, and sensitive sample preparation technique was successfully used to determine benzoylurea insecticides in environmental water samples.

14.
Chem Biol Interact ; 308: 198-205, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31112718

RESUMO

BACKGROUND: Matrine, a traditional Chinese medicine, has been reported to exert anti-tumor effects in several types of cancers. Here, we explored the anti-tumor effects of matrine on the glioma cells. METHODS: Glioma cell line U251 cells were treated with matrine to assess viability and proliferation using CCK8 and EdU assays. PI/FITC staining was performed for apoptosis assay. Transfections were performed for circRNA-104075 or Bcl-9 overexpression. Western blot analysis was performed to evaluate changes of protein levels and changes of gene level were detected by qRT-PCR in U251 cells. RESULTS: Matrine suppressed cell viability while induced apoptosis and autophagy in U251 cells. Matrine also decreased circRNA-104075 expression significantly. Overexpression of circRNA-104075 was found to counteract the inhibitory effects of matrine on cell proliferation and promoting effects on apoptosis and autophagy in U251 cells. Moreover, the suppressed Wnt/ß-catenin and PI3K/AKT signaling pathways by matrine were activated by circRNA-104075 overexpression. Furthermore, Bcl-9 expression was also down-regulated by matrine treatment. Bcl-9 overexpression elevated the decreased cell proliferation while suppressed the increased apoptosis and autophagy induced by matrine in U251 cells. CONCLUSION: Taken together, the present findings suggested that matrine induced apoptosis and autophagy through down-regulating circ-104075 and Bcl-9 expression via inhibition of PI3K/AKT and Wnt-ß-catenin pathways in glioma cells. The present study provides a foundation for further preclinical and clinical evaluations of matrine as a glioma therapy.


Assuntos
Alcaloides/farmacologia , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Proteínas de Neoplasias/metabolismo , Quinolizinas/farmacologia , RNA/metabolismo , Linhagem Celular Tumoral , Regulação para Baixo/efeitos dos fármacos , Glioma/metabolismo , Glioma/patologia , Humanos , Medicina Tradicional Chinesa , Proteínas de Neoplasias/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA/genética , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição
15.
Int J Nurs Stud ; 92: 73-78, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30743198

RESUMO

BACKGROUND: Distance from the tip of the nose to earlobe to xiphisternum is commonly used to determine the length of nasogastric tube to be inserted. However, it is not evidence-based and frequently leads to improper positioning. OBJECTIVES: This study evaluated four formulae and the distance from the tip of the nose to earlobe to xiphisternum in estimating the internal length of nasogastric tube required for optimal positioning. DESIGN: Observational Study. SETTINGS: Tertiary hospital in Singapore involving patients from the medical and surgical intensive care units and a neurosurgical ward. PARTICIPANTS: Inclusion criteria were patients who required a nasogastric tube insertion and age > = 21 years old and =<85 years old. Patients who required an orogastric tube insertion or did not require a chest x-ray post nasogastric tube insertion were excluded. METHODS: Upon nasogastric tube insertion, the external length of the tube was measured and the corresponding internal length calculated. Several anatomical measurements were taken as required in the formulae below: 1. ((Distance from tip of nose to earlobe to xiphisternum-50 cm)/2) + 50 cm. 2. 29.38 + 4.53*gender+0.34*distance from nose to umbilicus with head flat on bed-0.06*weight (gender = 1 for male, and 0 for female). 3. Distance from xiphisternum to earlobe to nose + 10 cm. 4. Distance from earlobe to xiphisternum to umbilicus-distance from tip of the nose to earlobe. Post insertion chest x-rays were examined to evaluate the position of the nasogastric tube. For those with optimal positioning, the distance from tip of the nose to earlobe to xiphisternum and the four formulae were compared to determine which provided the least difference with the internal length of the nasogastric tube. RESULTS: Ninety-two participants were recruited. The average age of the cohort was 62.9 years old with 54% being male. Twenty-five had nasogastric tubes in optimal position; 13 had it too short and 54 had it too long. For nasogastric tubes in optimal position, distance from xiphisternum to earlobe to nose + 10 cm provided the best estimate of the internal length. Average difference between the distance from xiphisternum to earlobe to nose + 10 cm and internal length of the nasogastric tubes in optimal position was only 1.8 cm which was by far the least difference compared to other formulae. CONCLUSION: This study found distance from xiphisternum to earlobe to nose + 10 cm to provide the best estimate for the internal length of nasogastric tube required. However, even this formula could result in placement that is not optimal due to anatomical differences.


Assuntos
Intubação Gastrointestinal/instrumentação , Adulto , Idoso , Idoso de 80 Anos ou mais , Antropometria , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Singapura , Adulto Jovem
16.
J Sep Sci ; 42(7): 1451-1458, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30677235

RESUMO

We present a simple method for the fabrication of a magnetic amino-functionalized zinc metal-organic framework based on a magnetic graphene oxide composite. The resultant framework exhibited a porous 3D structure, high surface area and good adsorption properties for nitrogen-containing heterocyclic fungicides. The adsorption process and capacity indicated that the primary adsorption mechanism might be hydrogen bonding and π-π conjugation. In addition, an optimized protocol for magnetic solid phase extraction was developed (such as adsorbent content, pH, and desorption solvent), and utilized for the extraction of nitrogen-containing heterocyclic fungicides from vegetable samples. Quantitation by high performance liquid chromatography coupled with tandem mass spectrometry offered a detection limit of 0.21-1.0 µg/L (S/N = 3) with correlation coefficients larger than 0.9975. These results demonstrate that magnetic amino-functionalized zinc metal-organic framewor is a promising adsorbent for the extraction and quantitation of nitrogen-containing heterocyclic fungicides.


Assuntos
Fungicidas Industriais/isolamento & purificação , Compostos Heterocíclicos/isolamento & purificação , Alface/química , Estruturas Metalorgânicas/química , Nitrogênio/isolamento & purificação , Extração em Fase Sólida , Adsorção , Cromatografia Líquida de Alta Pressão , Fungicidas Industriais/química , Grafite/química , Compostos Heterocíclicos/química , Fenômenos Magnéticos , Estruturas Metalorgânicas/síntese química , Nitrogênio/química , Tamanho da Partícula , Propriedades de Superfície , Espectrometria de Massas em Tandem , Zinco/química
17.
J Chromatogr A ; 1589: 10-17, 2019 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-30591248

RESUMO

In this study, four triazine herbicides-namely, simazine, ametryn, prometryn and terbuthylazine-were separated and determined using high-performance liquid chromatography coupled with ultraviolet detector (HPLC-UVD). The deep eutectic solvent (DES) formed by tetrabutylammonium chloride ([N4444]Cl, TBA) and ethylene glycol (EG) was selected as the extraction solvent of vortex-assisted reversed-phase liquid-liquid microextraction (VA-RPLLME). The application of the hydrophilic DES expands the range of choice for LLME. The experimental parameters affecting the extraction recoveries, including the amount of the DES, the sample volume and the vortex time, were investigated and optimized by the design of experiments (DoE) methodology. A quadratic model, namely central composite face-centered (CCF) design featuring 20 runs was used instead of the conventional trial and error approach. Under optimum conditions, the limits of determination (LODs) of the method were 0.60-1.50 µg L-1. The enrichment factors for the analytes ranged from 27 to 31. The extraction recoveries were in the range of 84.1-104.9%, and the intra-day, inter-day and intermediate relative standard deviations (RSDs) were less than 8.4%. Finally, the method was applied for the determination of triazine herbicides in vegetable oil samples. The obtained recoveries were in the range of 60.1-107.2% and RSDs were lower than 8.1%. In general, VA-RPLLME can be complementary to the present available methods for the determination of triazine herbicides in vegetable oil samples.


Assuntos
Cromatografia de Fase Reversa/métodos , Herbicidas/isolamento & purificação , Microextração em Fase Líquida/métodos , Óleos Vegetais/química , Plantas Comestíveis/química , Solventes/química , Triazinas/isolamento & purificação , Limite de Detecção , Reprodutibilidade dos Testes
18.
J Cell Biochem ; 2018 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-30417553

RESUMO

Glioma is a common primary brain tumor with high mortality rate and poor prognosis. Long noncoding RNA maternally expressed gene 3 (MEG3) is a tumor suppressor in diverse cancer types. However, the role of MEG3 in glioma remains unclear. We aimed to explore the effects of MEG3 on U251 cells as well as the underlying mechanisms. U251 cells were stably transfected with different recombined plasmids to overexpress or silence MEG3. Effects of aberrantly expressed MEG3 on cell viability, migration, apoptosis, expressions of apoptosis-associated and autophagy-associated proteins, and phosphorylated levels of key kinases in the PI3K/AKT/mTOR pathway were all evaluated. Then, messenger RNA (mRNA) and protein expression of Sirt7 in cells abnormally expressing MEG3 were estimated. In addition, effects of abnormally expressed MEG3 and Sirt7 on U251 cells were determined to reveal the underlying mechanism of MEG3-associated modulation. Cell viability and migration were significantly reduced by MEG3 overexpression whereas cell apoptosis as well as Bax and cleaved caspase-3/-9 proteins were obviously induced. Beclin-1 and LC3-II/LC3-I were upregulated and p62 was downregulated in MEG3 overexpressed cells. In addition, the autophagy pharmacological inhibitor (3-methyladenine, 3-MA) affected the effect of MEG3 overexpression on cell proliferation. Furthermore, the phosphorylated levels of key kinases in the PI3K/AKT/mTOR pathway were all reduced by MEG3 overexpression. Sirt7 was positively regulated by MEG3 expression, and effects of MEG3 overexpression on U251 cells were ameliorated by Sirt7 silence. MEG3 suppressed cell proliferation and migration but promoted autophagy in U251 cells through positively regulating Sirt7, involving in the inhibition of the PI3K/AKT/mTOR pathway.

19.
Sensors (Basel) ; 18(12)2018 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-30486466

RESUMO

Due to their unique optical properties, narrow size distributions, and good biological affinity, gold nanoparticles have been widely applied in sensing analysis, catalytic, environmental monitoring, and disease therapy. The color of a gold nanoparticle solution and its maximum characteristic absorption wavelength will change with the particle size and inter-particle spacing. These properties are often used in the detection of hazardous chemicals, such as pesticide residues, heavy metals, banned additives, and biotoxins, in food. Because the gold nanoparticles-colorimetric sensing strategy is simple, quick, and sensitive, this method has extensive applications in real-time on-site monitoring and rapid testing of food quality and safety. Herein, we review the preparation methods, functional modification, photochemical properties, and applications of gold nanoparticle sensors in rapid testing. In addition, we elaborate on the colorimetric sensing mechanisms. Finally, we discuss the advantages and disadvantages of colorimetric sensors based on gold nanoparticles, and directions for future development.


Assuntos
Inocuidade dos Alimentos , Ouro/química , Nanopartículas Metálicas/química , Técnicas Biossensoriais/métodos , Colorimetria/métodos
20.
Cell Physiol Biochem ; 49(5): 2012-2021, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30244244

RESUMO

BACKGROUND/AIMS: Ligustrazine (LSZ) has been identified as an antitumor agent against some types of cancers. Nevertheless, its ability to inhibit growth, migration and invasion of medulloblastoma cells is still unclear. This study aimed to explore the effect of LSZ on Daoy cells. METHODS: The effects of LSZ on viability, proliferation, apoptosis, migration, and invasion of Daoy cells were analyzed by CCK-8, BrdU, flow cytometry and Transwell assays, respectively. The effect of LSZ on miR-211 expression was analyzed by qRT-PCR. miR-211 inhibitor transfection was performed to suppress miR-211 expression. The effects of LSZ on apoptosis-related factors, MMP-2, MMP-9, and Vimentin (Vim), as well as main factors of PI3K/AKT and mTOR pathways were analyzed by Western blot. RESULTS: LSZ inhibited viability but promoted apoptosis of Daoy cells. Additionally, the proliferative, migratory and invasive abilities of Daoy cells were decreased by LSZ. Meanwhile, LSZ promoted the activations of Caspase-3 and Caspase-9, increased Bax level, decreased Bcl-2 level, as well as inhibited the expressions of MMP-2, MMP-9 and Vim. Additionally, we found that LSZ enhanced miR-211 expression and exerted its anti-medulloblastoma effect by up-regulation of miR-211. Furthermore, LSZ inhibited PI3K/AKT and mTOR signaling pathways by up-regulating miR-211. CONCLUSION: LSZ suppressed medulloblastoma Daoy cells by up-regulating miR-211 and further modulating the activations of PI3K/AKT and mTOR signaling pathways.


Assuntos
Proliferação de Células/efeitos dos fármacos , MicroRNAs/metabolismo , Pirazinas/farmacologia , Regulação para Cima/efeitos dos fármacos , Vasodilatadores/farmacologia , Antagomirs/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Caspase 3/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Neoplasias Cerebelares/metabolismo , Neoplasias Cerebelares/patologia , Humanos , Metaloproteinase 2 da Matriz/metabolismo , Meduloblastoma/metabolismo , Meduloblastoma/patologia , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Pirazinas/química , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Vasodilatadores/química
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