Repositorio institucional - Concytec
Not a member yet
3190 research outputs found
Sort by
Species delimitation of southeast pacific angel sharks (Squatina spp.) reveals hidden diversity through dna barcoding
No full textAngel sharks are distributed worldwide in tropical to subtropical waters. Across the Eastern Pacific Ocean (EPO), two valid species are reported: The Pacific angelshark Squatina californica and the Chilean angelshark Squatina armata; however, there is still uncertainty about their geographic distribution, mainly along the northern Peru coast where the species have been reported to be sympatric. The aim of this study is to describe the genetic differences between the genus Squatina from the EPO, including samples from northern Peru, and using DNA barcoding and three species delimitation models: Poisson tree processes (PTP) model, Bayesian implementation of the PTP (bPTP) model and the general mixed Yule coalescent (GMYC) model. The three approaches summarized 19 nominal Squatina species in 23 consensus Molecular Taxonomic Units (MOTU). Only 16 of them were in accordance with taxonomic identifications. From the EPO, four Squatina MOTUs were identified, one from North America (S. californica USA/Mexico) and three sampled in northern Peru, S. californica Peru, S. armata and Squatina sp. (a potential new species). This study contributes to the management and conservation policies of angel sharks in Peru, suggesting the presence of an undescribed species inhabiting the northern Peruvian coast. The use of molecular approaches, such as DNA barcoding, has the potential to quickly flag undescribed species in poorly studied regions, including the Southeast Pacific, within groups of ecologically and economically important groups like angel sharks. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Ground state solutions for a class of nonlocal regional Schrödinger equation with nonperiodic potentials
No full textIn this article, we deal with the nonlinear Schrödinger equation with nonlocal regional diffusion 0.1 (Formula presented.) where 0 < ? < 1, n ? 2, and (Formula presented.) is a continuous function. The operator (Formula presented.) is a variational version of the nonlocal regional Laplacian defined as (Formula presented.) where (Formula presented.) be a positive function. Considering that ?, V, and f(·, t) are periodic or asymptotically periodic at infinity, we prove the existence of ground state solution of (1) by using Nehari manifold and comparison method. Furthermore, in the periodic case, by combining deformation-type arguments and Lusternik–Schnirelmann theory, we prove that problem (1) admits infinitely many geometrically distinct solutions. © 2020 John Wiley & Sons, Ltd.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Global DNA hypermethylation pattern and unique gene expression signature in liver cancer from patients with Indigenous American ancestry
No full textThis work was supported by the Alliance pour les Sciences de la Vie et de la Santé (AVIESAN), ITMO Cancer ENV201408 (to S.B.) and the Ligue Contre le Cancer (to P.P.). J.P.C. was a recipient of a doctoral scholarship from the Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FONDECYT) 212-2015-FONDECYT and was supported by a fellowship from Campus France 941211E; L.C. was supported by a doctoral fellowship from IRD ARTS-2016-878573B; I.L. was supported by a postdoctoral fellowship from the Fondation ARC pour la Recherche sur le Cancer PDF20170505624; J.J.F. has received funding from the Agence Nationale de la Recherche (ANR) under the Investments for the Future program 11-LABX-0068; S.C.Z. and E.R. have received funding from the World Bank Group and FONDECYT-CONCYTEC under the Research Infrastructure Improvement program 016-2018-FONDECYT/BM; and S.B. has received funding from the European Union’s Horizon 2020 Framework program under the Marie Skłodowska-Curie Actions 823935.Hepatocellular carcinoma (HCC) usually afflicts individuals in their maturity after a protracted liver disease. Contrasting with this pattern, the age structure of HCC in Andean people displays a bimodal distribution with half of the patients developing HCC in adolescence and early adulthood. To deepen our understanding of the molecular determinants of the disease in this population, we conducted an integrative analysis of gene expression and DNA methylation in HCC developed by 74 Peruvian patients, including 39 adolescents and young adults. While genome-wide hypomethylation is considered as a paradigm in human HCCs, our analysis revealed that Peruvian tumors are associated with a global DNA hypermethylation. Moreover, pathway enrichment analysis of transcriptome data characterized an original combination of signatures. Peruvian HCC forgoes canonical activations of IGF2, Notch, Ras/MAPK, and TGF-β signals to depend instead on Hippo/YAP1, MYC, and Wnt/β-catenin pathways. These signatures delineate a homogeneous subtype of liver tumors at the interface of the proliferative and non-proliferative classes of HCCs. Remarkably, the development of this HCC subtype occurs in patients with one of the four Native American mitochondrial haplogroups A-D. Finally, integrative characterization revealed that Peruvian HCC is apparently controlled by the PRC2 complex that mediates cell reprogramming with massive DNA methylation modulating gene expression and pinpointed retinoid signaling as a potential target for epigenetic therapy. © 2021 Cerapio et al.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Identification and culture of proliferative cells in abnormal taenia solium larvae: Role in the development of racemose neurocysticercosis
No full textThis work was supported by National Council for Science, Technology, and Technological Innovation (CONCYTEC) – World Bank, through its executing unit National Fund for the Development of Science, Technology, and Technological Innovation (FONDECYT) contract [E033-01-08-2018-FONDECYT/Banco Mundial Programas de Doctorado en A´reas Estrate´gicas y Generales], Fogarty International Center-National Institutes of Health Training grant D43 TW001140, and by Intramural National Institutes of Allergy and Infectious Diseases (NIAID), National Institutes of Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Racemose neurocysticercosis is an aggressive disease caused by the aberrant expansion of the cyst form of Taenia solium within the subarachnoid spaces of the human brain and spinal cord resulting in a mass effect and chronic inflammation. Although expansion is likely caused by the proliferation and growth of the parasite bladder wall, there is little direct evidence of the mechanisms that underlie these processes. Since the development and growth of cysts in related cestodes involves totipotential germinative cells, we hypothesized that the expansive growth of the racemose larvae is organized and maintained by germinative cells. Here, we identified proliferative cells expressing the serine/threonine-protein kinase plk1 by in situ hybridization. Proliferative cells were present within the bladder wall of racemose form and absent from the homologous tissue surrounding the vesicular form. Cyst proliferation in the related model species Taenia crassiceps (ORF strain) occurs normally by bud-ding from the cyst bladder wall and proliferative cells were concentrated within the growth buds. Cells isolated from bladder wall of racemose larvae were established in primary cell culture and insulin stimulated their proliferation in a dose-dependent manner. These findings indicate that the growth of racemose larvae is likely due to abnormal cell proliferation. The different distribution of proliferative cells in the racemose larvae and their sensitivity to insulin may reflect significant changes at the cellular and molecular levels involved in their tumor-like growth. Parasite cell cultures offer a powerful tool to characterize the nature and formation of the racemose form, understand the developmental biology of T. solium, and to identify new effective drugs for treatment. © 2021 Orrego et al.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Dielectric Permittivity Sensor Based on Planar Open-Loop Resonator
No full textAccurate characterization of the dielectric properties of solids and, especially, substrates is crucial for circuitry design and development. For applications requiring low cost, wieldy systems, many attempts have been made involving planar resonant microwave devices. However, most of them have a configuration in which the sample is placed onto the substrate. As a novelty, a structure considering the sample placement into a more sensitive area is presented and analyzed in this letter. The design of this kind of sensors is discussed, and the measurement results are presented. The proposed device is shown to be capable of measuring the full complex permittivity of the sample, and the results compare well with other previous attempts. © 2017 IEEE.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Transparency-based protocol for decision-making regarding seismic rehabilitation projects of public buildings
No full textMotivation and problem definition: A large number of public buildings designed with obsolete criteria are at high seismic risk and in need of structural rehabilitation. The task of selecting the optimal strategy poses important challenges for decision-makers due to the variety of intervention options and the fact that the construction sector is perceived to be one of the most corrupt in the economy. Objective: Given that transparency is an efficient anti-corruption strategy, a protocol is proposed for decision-making in seismic rehabilitation projects of public infrastructure that incorporates criteria which serve to increase transparency in the project development. Methods: Firstly, the literature was reviewed to describe current practices and regulations linked to decision-making in seismic rehabilitation/retrofitting of buildings. Secondly, relevant criteria that should be taken into account to favor transparency in decision-making were proposed. Thirdly, these criteria were integrated into a protocol that uses information and communication technologies (ICTs), Building Information Modeling (BIM), and collaborative methodologies that involve all stakeholders that will participate in the decision-making process. Finally, the protocol was applied to a real decision-making case study for the selection of alternatives for large-scale reinforcement of state schools in the city of Lima. Results: The criteria of auditability or ease of control of the construction process is well regarded by stakeholders as a mechanism to increase transparency. Including these transparency criteria could influence the selection of reinforcement alternatives, especially if the profile of stakeholders is environmentally-oriented. The sensitivity analysis confirmed the dependency of the selection on the decision-maker profile. © 2021 Elsevier LtdFondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Rheological, bioactive properties and sensory preferences of dark chocolates with partial incorporation of Sacha Inchi (Plukenetia volubilis L.) oil
No full textWe studied the effect of substituting partially, cocoa butter (CB) with Sacha Inchi (Plukenetia volubilis L.) oil (SIO) on rheology, bioactive properties, and sensory preferences in potentially functional chocolate. For this 70% dark chocolates were prepared and the CB was substituted with 1.5%, 3%, and 4.5% of SIO. Hardness and viscosity of the SIO-chocolates were significantly reduced compared to the control (5451 ± 658 g; 17.01 ± 0.94 Pa s, respectively). Total phenolic content remained constant while the antioxidant capacity increased up to IC50 of 2.48 ± 0.10 as the content of SIO increased. The Casson yield stress and Casson plastic viscosity decreased as the amount of SIO increased. Chocolates with 4.5% SIO had a similar color, better glossiness, preferable snap attributes, and were more accepted (7.50 ± 0.08) compared to the control (p < 0.05), measured with a hedonic scale. Then, SIO can improve the bioactive properties of dark chocolates obtaining a potentially functional food with acceptable physicochemical characteristics. SIO can be considered as a new cocoa butter equivalent.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
An approach of social navigation based on proxemics for crowded environments of humans and robots
No full textNowadays, mobile robots are playing an important role in different areas of science, industry, academia and even in everyday life. In this sense, their abilities and behaviours become increasingly complex. In particular, in indoor environments, such as hospitals, schools, banks and museums, where the robot coincides with people and other robots, its movement and navigation must be programmed and adapted to robot-robot and human-robot interactions. However, existing approaches are focused either on multi-robot navigation (robot-robot interaction) or social navigation with human presence (human-robot interaction), neglecting the integration of both approaches. Proxemic interaction is recently being used in this domain of research, to improve Human-Robot Interaction (HRI). In this context, we propose an autonomous navigation approach for mobile robots in indoor environments, based on the principles of proxemic theory, integrated with classical navigation algorithms, such as ORCA, Social Momentum, and A*. With this novel approach, the mobile robot adapts its behaviour, by analysing the proximity of people to each other, with respect to it, and with respect to other robots to decide and plan its respective navigation, while showing acceptable social behaviours in presence of humans. We describe our proposed approach and show how proxemics and the classical navigation algorithms are combined to provide an effective navigation, while respecting social human distances. To show the suitability of our approach, we simulate several situations of coexistence of robots and humans, demonstrating an effective social navigation. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Xanthation of alginate for heavy metal ions removal. Characterization of xanthate-modified alginates and its metal derivatives
No full textXanthates are widely used in mining industry as collectors for its high affinity towards metal sulfides and precious metal ores. The possibility of using alginate for xanthation has not been explored yet despite the feasibility by the presence of hydroxyl groups alongside the polymeric chains. Therefore, this work aims to evaluate the alginate as a matrix for xanthation and its application on heavy metal ions removal. In order to obtain green materials, important pararmeter were explored such as the effect of reaction time (4–12 h), type of base (NaOH/KOH) and amount of carbon disulfide (2–10%v/v). Xanthated alginates were analyzed by NMR techniques and evidence of β-elimination was detected at 5.45 ppm. Furthermore, the presence of S element was confirmed by EDS mapping technique, while XRD showed a semi-crystalline structure. On the other hand, the chemical shifts of δ(C=S) and ν(C=S) bands were found around 863–805 cm−1 and 662–602 cm−1 respectively. Also, a shoulder at 182 ppm is appreciated by NMR in solid state attributed to C[dbnd]S group. According to FESEM analyses, morphology of xanthated alginates is affected by interaction with heavy metal ions. Finally, suitable materials for the removal of heavy metal ions were established at optimum pH values. © 2020Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Bioclimatic approach for rural dwellings in the cold, high Andean region: A case study of a Peruvian house
No full textThis paper presents a rural exemplar house built in San Francisco de Raymina (a high Andean village 3700 masl) in southern Peru that integrates passive and sustainable solar heating techniques. A climatic analysis of this village was carried out using measurements of meteorological parameters recorded throughout a whole year. The annually averaged temperature, relative humidity and horizontal daily solar energy were 8.3 °C, 73.1% and 5.2 kWh/m2, respectively. The temperatures outside and inside the most rural dwellings are almost the same, so they do not offer any protection specially, during nights when the temperature can reach values below zero. The thermal behavior of the house was modeled with the m2m tool, and an experimental validation was carried out. With the use of m2m, it was possible to create an energy balance during the month of June 2014 (the winter cold and dry season) to determine the energy loss/gain contributions by each wall and to assess how air exchanges (the flow rates of which were deduced using an inversion approach, as they could not be directly measured) between the exterior and interior influence the thermal behavior of the whole house. Infiltration contributed approximately 48.6% of the daily energy losses, while the main solar gains were from the skylights (21.8%) and the adobe walls, which absorbed heat during the day and released heat at night. © 2020 Elsevier B.V.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy