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1,169
result(s) for
"Contreras, H."
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Existence of entropy weak solutions for 1D non-local traffic models with space-discontinuous flux
by
Contreras, H. D.
,
Chiarello, F. A.
,
Villada, L. M.
in
Applications of Mathematics
,
Approximation
,
Computational Mathematics and Numerical Analysis
2023
We study a 1D scalar conservation law whose non-local flux has a single spatial discontinuity. This model is intended to describe traffic flow on a road with rough conditions. We approximate the problem through an upwind-type numerical scheme and provide compactness estimates for the sequence of approximate solutions. Then, we prove the existence and the uniqueness of entropy weak solutions. Numerical simulations corroborate the theoretical results and the limit model as the kernel support tends to zero is numerically investigated.
Journal Article
Silencing of the transcriptional factor ZEB1 alters the steroidogenic pathway, and increases the concentration of testosterone and DHT in DU145 cells
by
Castellón, E.A
,
Orellana-Serradell, O
,
Villar, P
in
Androgens
,
Care and treatment
,
Cell culture
2019
Prostate cancer (PCa) is the second most common type of male malignancy worldwide. The transcription factor zinc finger E-box binding homeobox 1 (ZEB1) is associated with epithelial-mesenchymal transition and is also involved in regulation of androgen receptor (AR) expression, the main ligands of which are testosterone and dihydrotestosterone (DHT). These androgens are synthesized through the steroidogenic pathway within the prostate, and their synthesis is altered in PCa. The present study aimed to determine the ZEB1-induced alterations in androgen synthesis and AR expression in the DU145 PCa cell line. Reverse transcription-quantitative polymerase chain reaction, western blotting and immunocytochemistry were used to determine the mRNA and protein expression levels, and cellular localization of steroidogenic pathway enzymes in the DU145 cell line in response to ZEB1 silencing. Furthermore, the concentrations of testosterone and DHT were detected in cell culture medium using ELISA. ZEB1-silenced cells exhibited an increase in testosterone and DHT production, an increase in AR expression and an alteration in the steroidogenic pathway. In particular, steroidogenic acute regulatory protein and 5α-reductase 2 expression levels were decreased, whereas cytochrome P450 family 17 subfamily A member 1, 5α-reductase 1, aldo-keto reductase family 1 member D1 and aldo-keto reductase family 1 member C2 expression levels were increased. In conclusion, the present study provided novel information regarding the regulation of intratumoral androgen production in PCa, which is relevant for the progression of the disease to a castration-resistant form.
Journal Article
ERG and Reggeon Field Theory
2018
In this paper we present our recent non perturbative functional renormalization group analysis of Reggeon Field Theory to the interactions of Pomeron and Odderon fields. We establish the existence of a fixed point and its universal properties, which exhibits a novel symmetry structure in the space of Odderon-Pomeron interactions. We briefly discuss the implications of our findings for the existence of an Odderon in high energy scattering.
Journal Article
Proapoptotic effect of endocannabinoids in prostate cancer cells
by
LLANOS, M.N
,
CASTELLÓN, E.A
,
POBLETE, C.E
in
Adenocarcinoma - pathology
,
Apoptosis - drug effects
,
Arachidonic Acids - pharmacology
2015
In the early stages, prostate cancer is androgen- dependent; therefore, medical castration has shown significant results during the initial stages of this pathology. Despite this early effect, advanced prostate cancer is resilient to such treatment. Recent evidence shows that derivatives of Cannabis sativa and its analogs may exert a protective effect against different types of oncologic pathologies. The purpose of the present study was to detect the presence of cannabinoid receptors (CB1 and CB2) on cancer cells with a prostatic origin and to evaluate the effect of the in vitro use of synthetic analogs. In order to do this, we used a commercial cell line and primary cultures derived from prostate cancer and benign prostatic hyperplasia. The presence of the CB1 and CB2 receptors was determined by immunohistochemistry where we showed a higher expression of these receptors in later stages of the disease (samples with a high Gleason score). Later, treatments were conducted using anandamide, 2-arachidonoyl glycerol and a synthetic analog of anandamide, methanandamide. Using the MTT assay, we proved that the treatments produced a cell growth inhibitory effect on all the different prostate cancer cultures. This effect was demonstrated to be dose-dependent. The use of a specific CB1 receptor blocker (SR141716) confirmed that this effect was produced primarily from the activation of the CB1 receptor. In order to understand the MTT assay results, we determined cell cycle distribution by flow cytometry, which showed no variation at the different cell cycle stages in all the cultures after treatment. Treatment with endocannabinoids resulted in an increase in the percentage of apoptotic cells as determined by Annexin V assays and caused an increase in the levels of activated caspase-3 and a reduction in the levels of Bcl-2 confirming that the reduction in cell viability noted in the MTT assay was caused by the activation of the apoptotic pathway. Finally, we observed that endocannabinoid treatment activated the Erk pathway and at the same time, produced a decrease in the activation levels of the Akt pathway. Based on these results, we suggest that endocannabinoids may be a beneficial option for the treatment of prostate cancer that has become nonresponsive to common therapies.
Journal Article
A New Glyptodont (Xenarthra: Cingulata) from the Late Miocene of Argentina: New Clues About the Oldest Extra-Patagonian Radiation in Southern South America
by
Barasoain, Daniel
,
Zurita, Alfredo E.
,
Croft, Darin A.
in
Animal Genetics and Genomics
,
Anthropology
,
Biomedical and Life Sciences
2022
Glyptodonts (Xenarthra, Cingulata) are one of the most amazing Cenozoic South American mammals, with some terminal forms reaching ca. two tons. The Paleogene record of glyptodonts is still poorly known, although some of their diversification is observable in Patagonian Argentina. Since the early and middle Miocene (ca. 19–13 Ma), two large clades can be recognized in South America. One probably has a northern origin (Glyptodontinae), while the other one, called the “austral clade”, is interpreted to have had an austral origin, with the oldest records represented by the “Propalaehoplophorinae” from the late early Miocene of Patagonian Argentina. In this scenario, the extra-Patagonian radiations are still poorly known, despite their importance for understanding the late Miocene and Pliocene diversity. Here, we carry out a comprehensive revision of late Miocene (Chasicoan Stage/Age) glyptodonts of central Argentina (Buenos Aires and San Juan provinces). Our results show that, contrary to what is traditionally assumed, it was a period of very low diversity, with only one species recognized in this region,
Kelenkura castroi
gen et sp. nov
.
Our phylogenetic analysis shows that this species represents the sister taxon of the remaining species of the “austral clade”, representing the first branch of the extra-Patagonian radiation. Additionally,
K. castroi
is the first taxon showing a “fully modern” morphology of the caudal tube.
Journal Article
Yield of white clover and orchard grass cultivated in mining passives adding black earth and compost as a substrate
by
Rojas-Felipe, E.
,
Contreras-Fernández, J. L.
,
Palomino-Pastrana, P. A.
in
BIOLOGY
,
cultivated pastures
,
mining environmental liabilities
2024
Abstract Mining environmental liabilities generate environmental pollution. The objective of the present study was to determine the yield of white clover (Trifolium repens) and orchard grass (Dactylis glomerata) cultivated in mining environmental passives adding black earth and compost as a substrate in the Buenaventura Julcani Huancavelica Company. The treatments were the combinations: 4: 3.1: 3.1: 3:1.1 kg of RP: RP, TN: RP, C: RP, TN, C respectively. They were distributed in four treatments with twelve experimental units for each species of leguminous and gramineous grass, we worked according to the completely randomized design (DCA) with a 2 x 4 factorial arrangement, the experimental unit being a treatment with twelve repetitions. The variables evaluated were: germination percentage (TG) and stem survival percentage (TST). For the statistical analysis, the SPSS software was used. Resumo O passivo ambiental da mineração gera poluição ambiental. O objetivo do presente estudo foi determinar a produtividade de trevo-branco (Trifolium repens) e capim-dos-pomares (Dactylis glomerata) cultivados em passivos ambientais de mineração adicionando terra preta e composto como substrato na Empresa Buenaventura Julcani Huancavelica. Os tratamentos foram as combinações: 4: 3,1: 3,1: 3:1,1 kg de RP: RP, TN: RP, C: RP, TN, C respectivamente. Foram distribuídos em quatro tratamentos com doze unidades experimentais para cada espécie de leguminosa e gramínea, trabalhou-se segundo o delineamento inteiramente casualizado (DCA) com arranjo fatorial 2 x 4, sendo a unidade experimental um tratamento com doze repetições. As variáveis avaliadas foram: porcentagem de germinação (TG) e porcentagem de sobrevivência do colmo (TST). Para a análise estatística foi utilizado o software SPSS.
Journal Article
Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment
2015
The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410 has been developed by Hamamatsu for dark matter direct detection experiments using liquid xenon as the target material. We present the results from the joint effort between the XENON collaboration and the Hamamatsu company to produce a highly radio-pure photosensor (version R11410-21) for the XENON1T dark matter experiment. After introducing the photosensor and its components, we show the methods and results of the radioactive contamination measurements of the individual materials employed in the photomultiplier production. We then discuss the adopted strategies to reduce the radioactivity of the various PMT versions. Finally, we detail the results from screening 286 tubes with ultra-low background germanium detectors, as well as their implications for the expected electronic and nuclear recoil background of the XENON1T experiment.
Journal Article
Exclusion of leptophilic dark matter models using XENON100 electronic recoil data
by
Garbini, M.
,
Vitells, O.
,
Aprile, E.
in
Astrophysics
,
Confidence intervals
,
Cosmology and Extra-Galactic Astrophysics
2015
Laboratory experiments searching for galactic dark matter particles scattering off nuclei have so far not been able to establish a discovery. We use data from the XENON100 experiment to search for dark matter interacting with electrons. With no evidence for a signal above the low background of our experiment, we exclude a variety of representative dark matter models that would induce electronic recoils. For axial-vector couplings to electrons, we exclude cross sections above 6 × 10–35 cm2 for particle masses of mx = 2 GeV/c2. Independent of the dark matter halo, we exclude leptophilic models as an explanation for the long-standing DAMA/LIBRA signal, such as couplings to electrons through axial-vector interactions at a 4.4σ. confidence level, mirror dark matter at 3.6σ, and luminous dark matter at 4.6σ.
Journal Article
Predictive Model for Water Consumption in a Copper Mineral Concentrator Plant Located in a Desert Area Using Machine Learning
by
Contreras Moreno, Eduardo H.
,
Flores Páez, Humberto
,
Pérez Cortés, Sebastián A.
in
Artificial intelligence
,
Copper
,
Datasets
2025
In this study, water consumption predictions are made based on data obtained from two copper mineral concentration plants located in the northern region of Chile, Antofagasta Region, measured during a year of mining operation. The area to which this operation belongs is characterized by a desert climate with average annual rainfall of less than 50 mm and maximum and minimum temperatures of 29 °C and 4 °C for summer, and 26 °C and −5 °C for winter, measured during 2022. To perform the predictions, a database corresponding to two concentration plants with daily measurements for a year was used, which were analyzed using four regression models using Machine Learning (ML) in Python: Support Vector Regressor (SVR), Extreme Gradient Boost (XGBoost), Artificial Neural Network (ANN), and Random Forest Regressor (RF). The predictions obtained by each of the ML models were studied using cross-validation hyperparameter tuning and identifying the variable with the greatest impact. The model with the best prediction results was ANN, as it yielded the lowest relative error in the predictions.
Journal Article
Conditioning of desert sandy soil and investigation of the ameliorative effects of poultry manure and bentonite treatment rate on plant growth
2022
Abstract Soil is the base of any ecosystem since it conserves nutrients and water for plant roots including agriculture and plantations. In dry and semi-arid places across the world, including the UAE, sandy soils are common. Their fertility is extremely low, and production is hampered by a number of agronomic challenges. Soil conditioner sources like bentonite and chicken manure might be used to improve the poor sandy soil attributes and hence boost soil productivity. From November 2019 to March 2020, an experiment was conducted to investigate the growth rates of Bougainvillea following bentonite and chicken manure amendments to sandy soil taken from Lehbab, Dubai. Bougainvillea was evaluated for its plant height (cm), max length of primary branch (cm), the number of leaves per plant, number of secondary branches, shoot weight (g), root length (cm), root weight (g), root/shoot ratio, chlorophyll contents, and chlorophyll a* and b*. In this experiment, a complete randomized design (CRD) with five treatments was used (10 replications per treatment). According to the findings, bentonite and chicken manure additions considerably influence the productive properties of sandy soil, as indicated by Bougainvillea growth. Additionally, the research suggests that Bougainvillea may be efficiently planted with 10% bentonite and 15% chicken manure applied to sandy soil, resulting in the healthiest plants compared to other amendments. Resumo O solo é a base de qualquer ecossistema, incluindo agricultura e plantações, pois conserva nutrientes e água para as raízes das plantas. Em lugares secos e semiáridos em todo o mundo, incluindo os Emirados Árabes Unidos, os solos arenosos são comuns. Sua fertilidade é extremamente baixa e a produção é prejudicada por uma série de desafios agronômicos. Fontes de condicionador de solo, como bentonita e esterco de galinha, podem ser usadas para melhorar os atributos do solo arenoso pobre e, portanto, aumentar a produtividade do solo. De novembro de 2019 a março de 2020, foi realizado um experimento para investigar as taxas de crescimento de buganvílias após bentonita e esterco de galinha em solo arenoso retirado de Lehbab, Dubai. A buganvília foi avaliada quanto à altura da planta (cm), comprimento máximo do ramo primário (cm), número de folhas por planta, número de ramos secundários, peso da parte aérea (g), comprimento da raiz (cm), peso da raiz (g), razão raiz/parte aérea, teores de clorofila e clorofila a* e b*. Neste experimento foi utilizado o delineamento inteiramente casualizado (DIC) com cinco tratamentos (10 repetições por tratamento). De acordo com os resultados, as adições de bentonita e esterco de galinha influenciam consideravelmente as propriedades produtivas do solo arenoso, conforme indicado pelo crescimento de buganvílias. Além disso, a pesquisa sugere que a buganvília pode ser plantada com eficiência com 10% de bentonita e 15% de esterco de galinha aplicado em solo arenoso, resultando, assim, em plantas mais saudáveis em comparação com outras alterações.
Journal Article