Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nanomaterials (Basel) ; 12(1)2021 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-35009958

RESUMO

For every three people on the planet, there are approximately two Tonnes (Te) of plastic waste. We show that carbon recovery from polystyrene (PS) plastic is enhanced by the coaddition of solvents to grow carbon nanotubes (CNTs) by liquid injection chemical vapour deposition. Polystyrene was loaded up to 4 wt% in toluene and heated to 780 °C in the presence of a ferrocene catalyst and a hydrogen/argon carrier gas at a 1:19 ratio. High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Raman spectroscopy were used to identify multiwalled carbon nanotubes (MWCNTs). The PS addition in the range from 0 to 4 wt% showed improved quality and CNT homogeneity; Raman "Graphitic/Defective" (G/D) values increased from 1.9 to 2.3; mean CNT diameters increased from 43.0 to 49.2 nm; and maximum CNT yield increased from 11.37% to 14.31%. Since both the CNT diameters and the percentage yield increased following the addition of polystyrene, we conclude that carbon from PS contributes to the carbon within the MWCNTs. The electrical contact resistance of acid-washed Bucky papers produced from each loading ranged from 2.2 to 4.4 Ohm, with no direct correlation to PS loading. Due to this narrow range, materials with different loadings were mixed to create the six wires of an Ethernet cable and tested using iPerf3; the cable achieved up- and down- link speeds of ~99.5 Mbps, i.e., comparable to Cu wire with the same dimensions (~99.5 Mbps). The lifecycle assessment (LCA) of CNT wire production was compared to copper wire production for a use case in a Boeing 747-400 over the lifespan of the aircraft. Due to their lightweight nature, the CNT wires decreased the CO2 footprint by 21 kTonnes (kTe) over the aircraft's lifespan.

2.
Cancer Discov ; 10(1): 104-123, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31649109

RESUMO

Allele-specific signaling by different KRAS alleles remains poorly understood. The KRAS G12R mutation displays uneven prevalence among cancers that harbor the highest occurrence of KRAS mutations: It is rare (∼1%) in lung and colorectal cancers, yet relatively common (∼20%) in pancreatic ductal adenocarcinoma (PDAC), suggesting context-specific properties. We evaluated whether KRASG12R is functionally distinct from the more common KRASG12D- or KRASG12V-mutant proteins (KRASG12D/V). We found that KRASG12D/V but not KRASG12R drives macropinocytosis and that MYC is essential for macropinocytosis in KRASG12D/V- but not KRASG12R-mutant PDAC. Surprisingly, we found that KRASG12R is defective for interaction with a key effector, p110α PI3K (PI3Kα), due to structural perturbations in switch II. Instead, upregulated KRAS-independent PI3Kγ activity was able to support macropinocytosis in KRASG12R-mutant PDAC. Finally, we determined that KRASG12R-mutant PDAC displayed a distinct drug sensitivity profile compared with KRASG12D-mutant PDAC but is still responsive to the combined inhibition of ERK and autophagy. SIGNIFICANCE: We determined that KRASG12R is impaired in activating a key effector, p110α PI3K. As such, KRASG12R is impaired in driving macropinocytosis. However, overexpression of PI3Kγ in PDAC compensates for this deficiency, providing one basis for the prevalence of this otherwise rare KRAS mutant in pancreatic cancer but not other cancers.See related commentary by Falcomatà et al., p. 23.This article is highlighted in the In This Issue feature, p. 1.


Assuntos
Carcinoma Ductal Pancreático/patologia , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Mutação , Neoplasias Pancreáticas/patologia , Pinocitose , Proteínas Proto-Oncogênicas p21(ras)/genética , Animais , Apoptose , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Proliferação de Células , Classe I de Fosfatidilinositol 3-Quinases/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Nanomedicine (Lond) ; 13(23): 2981-2993, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30501557

RESUMO

AIM: Glycoconjugated C60 derivatives are of particular interest as potential cancer targeting agents due to an upregulated metabolic glucose demand, especially in the case of pancreatic adenocarcinoma and its dense stroma, which is known to be driven by a subset of pancreatic stellate cells. MATERIALS & METHODS: Herein, we describe the synthesis and biological characterization of a hexakis-glucosamine C60 derivative (termed 'Sweet-C60'). RESULTS: Synthesized fullerene derivative predominantly accumulates in the nucleus of pancreatic stellate cells; is inherently nontoxic up to concentrations of 1 mg/ml; and is photoactive when illuminated with blue and green light, allowing its use as a photodynamic therapy agent. CONCLUSION: Obtained glycoconjugated nanoplatform is a promising nanotherapeutic for pancreatic cancer.


Assuntos
Fulerenos/uso terapêutico , Glicoconjugados/síntese química , Neoplasias Pancreáticas/tratamento farmacológico , Células Estreladas do Pâncreas/efeitos dos fármacos , Fármacos Fotossensibilizantes/uso terapêutico , Adenocarcinoma/tratamento farmacológico , Anticorpos/metabolismo , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Terapia Baseada em Transplante de Células e Tecidos/métodos , Fulerenos/efeitos adversos , Humanos , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/efeitos adversos , Neoplasias Pancreáticas
4.
Sci Rep ; 7(1): 11299, 2017 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-28900126

RESUMO

Surgical margin status in cancer surgery represents an important oncologic parameter affecting overall prognosis. The risk of disease recurrence is minimized and survival often prolonged if margin-negative resection can be accomplished during cancer surgery. Unfortunately, negative margins are not always surgically achievable due to tumor invasion into adjacent tissues or involvement of critical vasculature. Herein, we present a novel intra-operative device created to facilitate a uniform and mild heating profile to cause hyperthermic destruction of vessel-encasing tumors while safeguarding the encased vessel. We use pancreatic ductal adenocarcinoma as an in vitro and an in vivo cancer model for these studies as it is a representative model of a tumor that commonly involves major mesenteric vessels. In vitro data suggests that mild hyperthermia (41-46 °C for ten minutes) is an optimal thermal dose to induce high levels of cancer cell death, alter cancer cell's proteomic profiles and eliminate cancer stem cells while preserving non-malignant cells. In vivo and in silico data supports the well-known phenomena of a vascular heat sink effect that causes high temperature differentials through tissues undergoing hyperthermia, however temperatures can be predicted and used as a tool for the surgeon to adjust thermal doses delivered for various tumor margins.


Assuntos
Hipertermia Induzida , Neoplasias/patologia , Neoplasias/terapia , Neovascularização Patológica/terapia , Animais , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/terapia , Linhagem Celular Tumoral , Sobrevivência Celular , Terapia Combinada , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Feminino , Humanos , Hipertermia Induzida/instrumentação , Hipertermia Induzida/métodos , Camundongos , Neoplasias/cirurgia , Células-Tronco Neoplásicas/metabolismo , Neovascularização Patológica/cirurgia , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/terapia , Células Estreladas do Pâncreas/metabolismo , Suínos , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto , Neoplasias Pancreáticas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...