Macroscopic fibers of carbon nanotubes (CNT) have emerged as an ideal architecture to exploit the exceptional properties of CNT building blocks in applications ranging from energy storage to ...reinforcement in structural composites. Controlled synthesis and scalability are amongst the most pressing challenges to further materialize the potential of CNT fibers. This work shows that under floating catalyst chemical vapor conditions in the direct spinning method, used both in research and industry, the ceramic reactor tube plays an unsuspected active role in CNT growth, leading for example to doubling of reaction yield when mullite (Al
Si
O
(x ≈ 0:4)) is used instead of alumina (Al
O
), but without affecting CNT morphology in terms of number of layers, purity or degree of graphitization. This behaviour is confirmed for different carbon sources and when growing either predominantly single-walled or multi-walled CNTs by adjusting promotor concentration. Analysis of large Si-based impurities occasionally found in CNT fiber fabric samples, attributed to reactor tube fragments that end up trapped in the porous fibers, indicate that the role of the reactor tube is in catalyzing the thermal decomposition of hydrocarbons, which subsequently react with floating Fe catalyst nanoparticles and produce extrusion of the CNTs and formation of an aerogel. Reactor gas analysis confirms that extensive thermal decomposition of the carbon source occurs in the absence of Fe catalyst particles, and that the concentration of different carbon species (e.g. carbon dioxide and ethylene) is sensitive to the reactor tube type. These finding open new avenues for controlled synthesis of CNT fibers by decoupling precursor decomposition from CNT extrusion at the catalyst particle.
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•Surface density affects crystallinity, varying CO2 photoreduction conversion and selectivity.•Optimum conversion results are obtained with a surface density close to 1g/m2.•An ...increase in CH3OH selectivity occurs with a decrease in the surface densities.•Peroxo and related carbonate surface species are detected as H2O oxidation products.•DC-magnetron sputtering is a sound tool to scale-up CO2 reduction photocatalysts.
Advancing in the photocatalyst scale-up is crucial for the development of highly efficient solar fuels production at industrial scale. Here, we report DC-magnetron sputtering as a suitable technique to produce photocatalytic TiO2 coatings for CO2 reduction with a view on process scalability. The crystallinity of the obtained TiO2 coatings varies with surface density, with amorphous or quasi-amorphous coatings obtained with very low densities, while UV light absorption coefficients show the opposite trend, which has been related to the proportionally higher abundace of surface defects and grain boundaries associated to the small crystal size and/or amorphicity of the lightest coatings. The as-prepared samples lead to the reduction of CO2 as demonstrated by 13C isotope tracing. An optimum catalyst area density of 1g/m2 (by geometric area) is obtained in terms of CO2 photoreduction production, which is ascribed to a compromise situation between crystallinity and absorption coefficient. Selectivity to the different reaction products also varies with the coating characteristics, with amorphous or quasi-amorphous light coatings favouring methanol formation, in contrast with the preferred CO evolution in heavier, crystalline ones. Raman spectroscopy reveals the formation of peroxo and peroxocarbonate species on the photocatalyst surface as oxidation products during the CO2 reduction, the accummulation of which is proposed to be related to the observed catalyst deactivation.
Aim
Hepatocellular carcinoma (HCC) is in the 10 leading cancer types, being difficult to detect as most of patients who develop this tumor have no symptoms other than those related to their ...long‐standing liver disease. The liver is constantly exposed to bacterial products, viral infection, alcohol or other products, which may be the cause of chronic liver damage, and thus an increasing risk for HCC. Toll‐like receptors (TLR) have gained an extraordinary interest in cancer research due to their role in several biological processes such as innate immune responses, the induction of adaptive immune responses, regulation of inflammation, would healing and carcinogenesis. Therefore, the aim of this study was to investigate the expression and clinical relevance of TLR3, 4 and 9 in HCC.
Methods
The expression levels of TLR3, TLR4 and TLR9 were analyzed in tumors from 30 patients with HCC. The analysis was performed by immunohistochemistry. Results were correlated with various clinicopathological findings and with overall survival.
Results
TLR3 was significantly high in large tumors (>4 cm in diameter) compared with small tumors (P < 0.05). Our results demonstrated that patients whose tumors showed both TLR4 and TLR9 positive immunostaining had poor prognosis. In addition, TLR9 expression by fibroblast‐like cells was significantly associated with a shortened overall survival (P = 0.015).
Conclusion
The results demonstrated an association between TLR3, TLR4 and TLR9 expression and tumor aggressiveness and poor prognosis in HCC.
Summary Objectives Head and neck squamous cell carcinomas (HNSCCs) are characterized by marked heterogeneity in their biological behavior and response to treatment. Our goal was the identification of ...biomarkers that can be used to predict response to chemotherapy in these patients. Materials and methods The expression of EGFR, p53, Cyclin D1, p16, p21, p27, p-AKT, HIF-1α, Caspase 3 and BCL2 was analyzed by immunohistochemistry in 41 primary laryngeal/hypopharyngeal squamous cell carcinomas of patients that received induction chemotherapy (cisplatin and 5-fluorouracil) as part of their treatment. Results Positive expression of p27 and BCL2 had a significant predictive value for chemotherapy response in univariate analysis. The combination of both proteins was not superior in predicting the response to chemotherapy. Furthermore, p27 expression was the only significant predictor of chemotherapy response in multivariate analysis ( P = 0.015). Conclusion p27 Expression may serve as predictive biomarker of response to induction chemotherapy in HNSCC patients.
Modification of metal oxides’ characteristics by decreasing the nanoparticles’ crystal size is usually interpreted in terms of increasing quantum size effects and/or oxygen vacancy concentration. ...However, some properties of TiO2 nanoparticles, such as water adsorption strength on anatase or photoactivity for toluene mineralization in the gas phase, are optimized when the mean anatase crystal size is close to 6 nm, indicating the action of two opposed effects. Here, we show that these effects are originated by the increasing acidity of bridging hydroxyls with decreasing crystal size. Increasing acidity favors, first, water hydrogen bonding to bridging hydroxyls and, then, simultaneously to bridging and terminal hydroxyls of adjacent particles, favoring nanoparticle agglomeration and interfacial hydroxyls and water stability. A too strong acidic character of bridging hydroxyls favors proton exchange of stabilized hydronium ions with bridging O2− and terminal hydroxyls, facilitating hydroxyl recombination and crystal growth.
Background: Squamous cell carcinoma of the oral cavity is a highly invasive neoplasm that spreads locally and metastasizes to regional lymph nodes. This process involves multiple proteolytic enzymes ...including matrilysin (MMP‐7) and membrane type I‐matrix metalloproteinase (MT1‐MMP). This study was designed to explore the association between MMP‐7 and MT1‐MMP in the invasiveness and prognosis of oral squamous cell carcinoma (OSCC).
Methods: About 4‐μM, formalin‐fixed, paraffin‐embedded tissue sections from 69 patients with OSCC were immunohistochemically studied using specific antibodies against MMP‐7 and MT1‐MMP proteins. Immunostaining was semiquantitatively scored, and results were correlated with histologic and clinical variables including clinical behavior and survival.
Results: MMP‐7 was observed only in cancer cells, and MT1‐MMP in both tumoral tissue and stroma. MMP‐7 expression was significantly correlated with lymph node metastasis (P = 0.03; RR = 3.2). MT1‐MMP showed a significant association with TIMP‐2 (in N+ cases) and p53 expression (P = 0.01). MMP‐7 and MT1‐MMP displayed a survival relevance, and in multivariate analysis they were independent prognostic indicators, particularly in neck node‐positive cases.
Podoplanin expression is attracting interest as a marker for cancer diagnosis and prognosis. We therefore investigated the expression pattern and clinical significance of podoplanin during the ...development and progression of laryngeal carcinomas.
Podoplanin expression was determined by immunohistochemistry in paraffin-embedded tissue specimens from 84 patients with laryngeal premalignancies and 53 patients with laryngeal squamous cell carcinomas. We found podoplanin expression extending from the basal to the suprabasal layer of the epithelium in 37 (44%) of 84 dysplastic lesions, whereas normal epithelium showed negligible expression. Patients carrying podoplanin-positive lesions had a higher laryngeal cancer incidence than those with negative expression reaching borderline statistical significance (51% versus 30%, P = 0.071). Podoplanin expression in laryngeal carcinomas exhibited two distinct patterns. 20 (38%) cases showed diffuse expression in most tumour cells and 33 (62%) focal expression at the proliferating periphery of tumour nests. High podoplanin expression was inversely correlated with T classification (P = 0.033), disease stage (P = 0.006), and pathological grade (P = 0.04). There was a trend, although not significant, towards reduced disease-specific survival for patients with low podoplanin levels (P = 0.31) and diffuse expression pattern (P = 0.08).
Podoplanin expression increases in the early stages of laryngeal tumourigenesis and it seems to be associated with a higher laryngeal cancer risk. Podoplanin expression in laryngeal squamous cell carcinomas, however, diminishes during tumour progression. Taken together, these data support a role for podoplanin expression in the initiation but not in the progression of laryngeal cancers.
In this work, TiO
2
has been modified by treating it thermally together with different proportions (0.5–15 wt%) of La
2
O
3
. The resulting materials have been extensively characterized by XRD, TEM, ...N
2
adsorption isotherms, temperature-programmed CO
2
desorption, Raman, UV–Vis photoluminescence and X-ray photoelectron spectroscopies. The activity tests of these materials for the gas-phase photocatalytic reduction of carbon dioxide show that the main products of the reaction are in all cases CO and CH
4
, together with H
2
from the parallel reduction of water. After the preparation procedure, La phases are best described as oxycarbonates, and lead to improved activity with respect to TiO
2
with La contents up to 5 wt%. Higher loadings do not, however, lead to further enhanced activity. Retarded electron–hole recombination and enhanced CO
2
adsorption are invoked as the key factors contributing to this activity improvement, which is optimized in the case of 0.5 wt% La leading to higher productions of CO and CH
4
and increased quantum efficiency with respect to titania.
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