2,679 research outputs found
In Vitro Effects of Selective COX and LOX Inhibitors and Their Combinations with Antineoplastic Drugs in the Mouse Melanoma Cell Line B16F10
The constitutive expression or overactivation of cyclooxygenase (COX) and lipoxygenase (LOX) enzymes results in aberrant metabolism of arachidonic acid and poor prognosis in melanoma. Our aim is to compare the in vitro effects of selective COX-1 (acetylsalicylic acid), COX-2 (meloxicam), 5-LOX (MK-886 and AA-861), 12-LOX (baicalein) and 15-LOX (PD-146176) inhibition in terms of proliferation (SRB assay), mitochondrial viability (MTT assay), caspase 3-7 activity (chemiluminescent assay), 2D antimigratory (scratch assay) and synthesis of eicosanoids (EIA) in the B16F10 cell line (single treatments). We also explore their combinatorial pharmacological space with dacarbazine and temozolomide (median effect method). Overall, our results with single treatments show a superior cytotoxic efficacy of selective LOX inhibitors over selective COX inhibitors against B16F10 cells. PD-146176 caused the strongest antiproliferation effect which was accompanied by cell cycle arrest in G1 phase and an >50-fold increase in caspases 3/7 activity. When the selected inhibitors are combined with the antineoplastic drugs, only meloxicam provides clear synergy, with LOX inhibitors mostly antagonizing. These apparent contradictions between single and combination treatments, together with some paradoxical effects observed in the biosynthesis of eicosanoids after FLAP inhibition in short term incubations, warrant further mechanistical in vitro and in vivo scrutiny
Three-dimensional scanning system based on a low-cost infrared sensor
Nowadays, with the availability of 3D printers, the
scanners for objects are becoming increasingly present since they
allow to replicate objects by 3D printing, especially for small scale
sizes. However, the majority of these technologies are expensive,
due to the complexity of this task. Therefore, this work presents
a prototype of a low-cost 3D scanning system for small objects
using a point cloud to stereolithography approach where it was
already validated in simulation in previous work. This concept
has a restriction that the objects must have a uniform shape,
i.e, without discontinuities. The architecture is composed of two
stepper motors, due to their precision, a rotating plate to allow
360 degrees scans and another rotating structure that allows the
infrared distance sensor to scan the object from bottom to top
(90 degrees). The prThis work has been supported by FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UIDB/05757/2020. The project that gave rise to these results received the support of a fellowship from ”la
Caixa” Foundation (ID 100010434). The fellowship code is LCF/BQ/DI20/11780028.info:eu-repo/semantics/publishedVersio
Bad news travels fast! | Notícia ruim corre depressa!
Many proverbs are created through everyday experience. Although many of them are readily understood by ordinary people, the more detailed view generates many questions and doubts related to their credibility. Motivated by one of these proverbs, in the present paper, we analyse propagation of news in the network of electronic contacts (e-mails). More specifically, we propose transmission protocols intended to reproduce properties of real systems. These protocols are simulated in a real e-mail network and in the random network proposed by p. Erdos and a. Rényi prize. The results suggest that news spreads faster in the random network. The hubs in the real network tend to attract the news, in prejudice to the less connected nodes
Cytokeratin 7/19 expression inN-diethylnitrosamine-induced mouse hepatocellular lesions: implications for histogenesis International
Hepatocellular carcinoma (HCC) is a common malignancy with poor clinical outcome, whose histogenesis is the subject of intense debate. Specifically, expression ofcytokeratins (CKs) 7 and 19, associated with aggressive biological behaviour, is proposed to reflect a possible progenitor cell origin or tumour dedifferentiation towardsa primitive phenotype. This work addresses that problem by studying CKs 7 and 19expression in N-diethylnitrosamine (DEN)-induced mouse HCCs. ICR mice weredivided into six DEN-exposed and six matched control groups. Samples were takenfrom each group at consecutive time points. Hyperplastic foci (13 lesions) occurredat 29-40 weeks (groups 8, 10 and 12) with diffuse dysplastic areas (19 lesions) andwith one hepatocellular adenoma (HCA) (at 29 weeks). HCCs (4 lesions) wereobserved 40 weeks after the first DEN administration (group 12). CKs 7 and 19showed identical expression patterns and located to large, mature hepatocytes, isolated or in small clusters. Hyperplastic foci and the single HCA were consistentlynegative for both markers, while dysplastic areas and HCCs were positive. Theseresults support the hypothesis that CKs 7 and 19 expression in hepatocellular malignancies results from a dedifferentiation process rather than from a possible progenitor cell origin
On Challenging Techniques for Constrained Global Optimization
This chapter aims to address the challenging and demanding issue of solving a continuous nonlinear constrained global optimization problem. We propose four stochastic methods that rely on a population of points to diversify the search for a global solution: genetic algorithm, differential evolution, artificial fish swarm algorithm and electromagnetism-like mechanism. The performance of different variants of these algorithms is analyzed using a benchmark set of problems. Three different strategies to handle the equality and inequality constraints of the problem are addressed. An augmented Lagrangian-based technique, the tournament selection based on feasibility and dominance rules, and a strategy based on ranking objective and constraint violation are presented and tested. Numerical experiments are reported showing the effectiveness of our suggestions. Two well-known engineering design problems are successfully solved by the proposed methods. © Springer-Verlag Berlin Heidelberg 2013.Fundação para a
Ciência e a Tecnologia (Foundation for Science and Technology), Portugal for the financial support under fellowship grant: C2007-UMINHO-ALGORITMI-04. The other authors acknowledge FEDER COMPETE, Programa Operacional Fatores de Competitividade (Operational Programme
Thematic Factors of Competitiveness) and FCT for the financial support under project grant:
FCOMP-01-0124-FEDER-022674info:eu-repo/semantics/publishedVersio
Resíduos da bananeira na alimentação de tambaqui: influência no desempenho zootécnico e controle de monogenea.
Considerando a relevância da espécie, a incidência do parasita monogenea nas brânquias da espécie e a possibilidade do uso dos resíduos da bananeira na alimentação, foi realizado um ensaio para avaliar a eficácia do uso desses resíduos da bananeira na nutrição e sanidade do tambaqui
Variação sazonal de matéria orgânica, umidade e pH em área de cana-de-açúcar.
Para se estudar os efeitos da agricultura intensiva sobre solos, foram realizadas pesquisas de caracterização microbiológica e físico-química de solos da microbacia do Espraiado, região de Ribeirão Preto, coletados de 9 pontos a profundidades de 0-20 e 80-90cm, mensalmente, durante 1996. Este trabalho apresenta os resultados da caracterização físico-química. Pela textura os solos foram classificados em 4 grupos. De maio a agosto, quando a umidade estava reduzida, observou-se uma elevação dos teores de matéria orgânica que coincidiram com maior acidez. A variação sazonal de pH atingiu 2 unidades. Em geral, o conteúdo de matéria orgânica foi menor a profundidade de 80-90cm, bem como os valores de pH
The distance to the Fornax Dwarf Spheroidal Galaxy
A large multicolour, wide-field photometric database of the Fornax dwarf
spheroidal galaxy has been analysed using three different methods to provide
revised distance estimates based on stellar populations in different age
intervals. The distance to Fornax was obtained from the Tip of the Red Giant
Branch measured by a new method, and using the luminosity of Horizontal Branch
stars and Red Clump stars correc ted for stellar population effects. Assuming a
reddening , the following distance moduli were derived:
based on the Tip of the Red Giant Branch,
from the level of the Horizontal Branch, and
using the Red Clump method. The weighted mean distance
modulus to Fornax is . All these measurements agree
within the errors, and are fully consistent with previous determinations and
with the distance measurements obtained in a companion paper from near-infrared
colour-magnitude diagrams.Comment: Accepted for publication on Monthly Notices of the Royal Astronomical
Societ
Study of the antioxidant power of the waste oil from palm oil bleaching clay
Palm oil is one of the most consumed oils, one of whose refining steps is the removal of pigments and other substances using bleaching clay as adsorbent. Worldwide production of this oil was 70 million tons in 2017, requiring 1 t of clay to produce 1000 t of refined oil. The residual bleaching clay, having an oil fraction (12.70%) rich in phenolics, carotenoids and tocopherols, was extracted in this study with ethanol to obtain an antioxidant-rich palm oil bleaching extract (POBE), with the aim of using it as a natural antioxidant source. The POBE antioxidant capacity determined by the DPPH method corresponded to a 20.29% inhibition of radical formation. The POBE was also tested for its potential to enhance oxidative stability of passion fruit, pracaxi and Brazil nut oils used as reference oils, and compared to common synthetic antioxidants (tert-butylhydroquinone and propyl gallate), either separately as controls or in mixtures with them. Besides the increased oxidative stability of these oils induced by the POBE, a positive synergistic effect between it and the synthetic antioxidants was observed. These results taken together suggest that the exploitation of the waste oil from bleaching clay as an additive to improve the oxidative stability of biofuels or lubricating oils is feasible
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