Examinando 3.2 Pasantías y ponencias por Título

Publicación

A Comparative Study on Activated Carbons Derived from a Broad Range of Agro-industrial Wastes in Removal of Large-Molecular-Size Organic Pollutants in Aqueous Phase

(Springer Nature, 2015)

Cruz, GJF

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Matejova, L

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Pirila, M

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Ainassaari, K

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Canepa, CA

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Solis, J

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Cruz, JF

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Solcova, O

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Keiski, RL

Microporous–mesoporous activated carbons from five different types of agro-industrial wastes were produced using chemical activation with ZnCl2 and carbonization at mild conditions of 600 °C, comprehensively characterized and investigated for removal of methylene blue (MB) in aqueous solution, a model large-molecular-size organic pollutant. The external part of the mango pit (mango seed husk) was used for the production of activated carbon (AC) for the first time. Despite that the raw agro-materials exhibited significantly different porosity, all activated carbons produced possessed well-developed microporous–mesoporous structures showing high surface areas and micropore volumes.

Publicación

A comparative study on the phenolic bioaccessibility, antioxidant and inhibitory effects on carbohydrate-digesting enzymes of maca and mashua powders

(Academic Press, 2020)

Paucar-Menacho L.M.

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Peñas E.

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Hernandez-Ledesma B.

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Frias J.

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Martínez-Villaluenga C.

The polyphenolic content of dehydrated maca (MA) and mashua (M) powders, promising functional ingredients, and their antioxidant activity and inhibition of carbohydrate digestion was evaluated following in vitro gastrointestinal digestion (GID). Moreover, the impact of steaming on bioaccessibility and bioactivity of the M phenolic fraction was investigated. MA phenolic fraction composed mainly of caffeic-4-O-glucosides showed high bioaccessibility (117.8%), antioxidant activity (142.9 μmol Trolox equivalents, TE/g) and weak effectiveness to inhibit carbohydrate digestion after GID. Anthocyanins were the major compounds in the M phenolic fraction with low bioaccessibility (22.4%), although a superior antioxidant activity (446.7 μmol TE/g) and modest inhibitory effects on carbohydrate digestion after GID. Generally, bioaccessibility and bioactivity of M decreased after steaming process. MA and M powders contain appreciable concentrations of phenolics, although M polyphenols were more effective on modulating carbohydrate digestion. © 2020 Elsevier Ltd

Publicación

A Comparison of Digital Modelling Techniques Analyzing a Section of Qhapaq Nan

(IEEE Xplore, 2015)

Retamozo, S

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Arce, D

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Aguilar, R

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Zvietcovich, F

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Quintana, M

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Castaneda, B

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Angeles, S

Total Station has been one of the most common acquisition devices for achieving maps through topographic survey. Nowadays, Terrestrial Laser Scanner (TLS) and Photogrammetry are commonly used to generate accurate meshes. In addition, commercial products such as Kinect offer low cost technology to acquire point-cloud information. The present paper aims to measure the accuracy of these digital modelling techniques by employing elevation contour maps, surface deviations and distance measurements. For this purpose, a 450 m sector of the Qhapaq Nan located in Lima-Peru, was selected as a case of study. A camera-enabled drone was used for acquiring pictures to obtain a high-resolution photogrammetric model. Subsequently, a 3D survey of the monument was conducted with a time-of-flight laser scanner. Contour elevation lines where extracted from TLS, Photogrammetry and Total Station models at the same depths in order to determine the precision of photogrammetry and laser scanner reconstructions. In addition, geometrical comparisons were performed among the 3D models above mentioned and the Kinect sensor. The comparison showed that TLS is the most accurate tool for 3D reconstruction. However, Photogrammetry and Kinect provided errors of less than one centimeter in accuracy.

Publicación

A computer algorithm for detection of tuberculosis bacilli in Ziehl Nellsen sputum smear images based on the adjustment of RGB primary component tones and geometric eccentricity

(International Institute of Informatics and Systemics, IIIS, 2017)

Del Carpio C.

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Dianderas E.

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Zimick M.

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Sheen P.

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Coronel J.

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Fuentes P.

;

Kemper G.

Publicación

A mixed methodology for detailed 3D modeling of architectural heritage

(Tayler & Francis Group, 2016)

Arce, D

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Retamozo, S

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Aguilar, R

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Castaneda, B

Architectural and archaeological heritage is the most representative part of history of a country. For these reasons, over the years, the scientific community has focused its attention on three-dimensional (3D) modeling techniques, conservation, structural analysis and other related applications. Laser scanning, shape from structured light, shape from silhouette, shape from video and shape from photometry are among the techniques that have been used over the past years for 3D modeling of archeological heritage. The application of 3D modeling can be found in several disciplines. In Architecture, it is used to generate digital models from which drawings can be produced. Aerial and terrestrial photogrammetry Photogrammetry is commonly used for digitization of 3D models in different applications due to the fast acquisition process and low cost of equipment. Digitization of structures with terrestrial laser scanner requires the usage of a correct methodology in order to generate a complete 3D model.

Publicación

A new Clathria (Demospongiae, Microcionidae) from Peru occurring on rocky substrates as well as epibiontic on Eucidaris thouarsii sea urchins

( 2011)

Aguirre, LK

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Hooker, Y

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Willenz, P

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Hajdu, E

Publicación

A new species of Bryophryne (Anura: Strabomantidae) from the Cordillera de Vilcabamba, southeastern Peruvian Andes

(Universidade de Sao Paulo, Agencia USP de Gestao da Informacao Academica (AGUIA), 2017)

Mamani, Luis

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Catenazzi, Alessandro

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Ttito, Alex

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Mallqui, Sergio

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Chaparro, Juan C.

A new species of Bryophryne (Anura: Strabomantidae) from the Cordillera de Vilcabamba, southeastern Peruvian Andes. We describe a new species of Bryophryne from the Cordillera de Vilcabamba in Department Cusco, in the southeastern Peruvian Andes. The new species differs from all other congeneric taxa, except B. flammiventris and B. gymnotis, by possessing a weakly defined tympanic membrane and tympanic annulus, by the presence of vocal sac and vocal slits in males, and by producing advertisement calls. The new species is distinguished from B. flammiventris and B. gynznotis by skin texture, presence of small, oblique dentigerous processes on the vomer, ventral coloration ranging from bluish-gray to whitish-gray with irregular or reticulate dark brown spots, and call composed of two or three notes. The new species is further characterized by having dorsal skin shagreen with tubercles, discontinuous dorsolateral folds, skin smooth on ventral surfaces of the body, and lateral fringes on fingers and toes. This species was found at the transition from montane forest to high Andean pupa, where it occurs in moist microhabitats under moss and rocks at elevations from 3519 to 3707 m a.s.l.

Publicación

Antioxidant properties of mashua (Tropaeolum tuberosum) phenolic extracts against oxidative damage using biological in vitro assays

( 2008)

Chirinos R.

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Campos D.

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Warnier M.

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Pedreschi R.

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Rees J.-F.

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Larondelle Y.

Publicación

Arsenic in Peruvian rice cultivated in the major rice growing region of Tumbes river basin

(Elsevier Ltd, 2020)

Mondal D.

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Periche R.

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Tineo B.

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Bermejo L.A.

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Rahman M.M.

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Siddique A.B.

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Rahman M.A.

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Solis J.L.

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Cruz G.J.F.

Arsenic (As) exposure from surface and groundwater in Peru is being recognised as a potential threat but there are limited studies on As in the food-chain and none on As in Peruvian rice. In this study, we have determined the As content in rice cultivated in the Tumbes river basin located in the northern province of Peru, an area known for extensive rice cultivation. We collected rice and soil samples from agricultural fields, soil was collected using grid sampling technique while rice was collected from the heaps of harvested crop placed across the fields. The average total As concentration in rice was 167.94 ± 71 μg kg−1 (n = 29; range 68.39–345.31 μg kg−1). While the rice As levels were not highly elevated, the As content of few samples (n = 7) greater than 200 μg kg−1 could contribute negatively to human health upon chronic exposure. Average concentration of As in soil was 8.63 ± 7.8 mg kg−1 (n = 30) and soil to grain transfer factor was 0.025 ± 0.018 for 12 matched samples. Compared to our previous pilot study in 2006 (samples collected from the same agricultural fields but not from exact locations) there was a 41% decrease in As soil concentration in this study. Rice samples collected in 2006 (n = 5) had a mean concentration of 420 ± 109 μg kg−1. Our data provides a baseline of rice grain As concentrations in Peruvian province of Tumbes and warrants further studies on factors affecting uptake of As by the rice varieties cultivated in Peru and any potential human health risks. © 2019 Elsevier Ltd

Publicación

Biomechanical study of proximal femur for designing stems for total hip replacement

(MDPI AG, 2020)

Solórzano W.

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Ojeda C.

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Lantada A.D.

Innovative hip implants should be designed in accordance with biomechanical models of the proximal femur and take into account both body weight and muscle action in order to improve usability and biomimetic performance. This article proposes a finite element analysis of the proximal femur using both cortical and trabecular regions and employing transverse isotropic properties with standardized loads taken from active and young patients. Maximum principal stresses are plotted to show the mechanical behavior of the femur and grouped to evaluate stress shielding. Tsai-Wu and the maximum principal stress fields are useful for finding the areas more prone to failure and analyzing the influence of the stems on femoral mechanics. Other parameters, such as the stem material, absence of neck and osteotomy level, are explained. This paper is expected to provide a guide for designers and surgeons of femoral stems for assessing qualitatively and quantitatively the risks of stress shielding. © 2020 by the authors.

Publicación

Bioprospection of native psychrotolerant plant-growth-promoting rhizobacteria from peruvian andean plateau soils associated with chenopodium quinoa

(Canadian Science Publishing, 2020)

Chumpitaz-Segovia C.

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Alvarado D.

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Ogata-Gutiérrez K.

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Zúñiga-Dávila D.

The Peruvian Andean Plateau, one of the main production areas of native varieties of Chenopodium quinoa, is exposed to abrupt decreases in environmental temperature, affecting crop production. Plant-growth-promoting rhizobacteria that tolerate low temperatures could be used as organic biofertilizers in this region. We aimed to bioprospect the native psychrotolerant bacteria of the quinoa rhizosphere in this region that show plant-growth-promoting traits. Fifty-one strains belonging to the quinoa rhizosphere were characterised; 73% of the total could grow at low temperatures (4, 6, and 15 °C), whose genetic diversity based on DNA amplification of interspersed repetitive elements (BOX) showed 12 different profiles. According to the 16S rRNA sequence, bacterial species belonging to the classes Beta-and Gammaproteobacteria were identified. Only three (6%) isolates identified as nonpathogenic bacteria exhibited plant-growth-promoting activities, like IAA production, phosphate solubilization, growth in a nitrogen-free medium, and ACC deaminase production at 6 and 15 °C. ILQ215 (Pseudomonas silesiensis) and JUQ307 (Pseudomonas plecoglossicida) strains showed significantly positive plant growth effects in aerial length (about 50%), radicular length (112% and 79%, respectively), and aerial and radicular mass (above 170% and 210%, respectively) of quinoa plants compared with the control without bacteria. These results indicate the potential of both psychrotolerant strains to be used as potential organic biofertilizers for quinoa in this region. © 2020, Canadian Science Publishing. All rights reserved.

Publicación

Caracterización morfológica y molecular de las especies del género Croton L. (Euphorbiaceae) denominadas “sangre de grado” en la Amazonía peruana

(Universidad Nacional Mayor de San Marcos, 2019)

Ore Rengifo, Malu Isaura

El género Croton es un género gigante que alberga a más de 1200 especies. Dentro de estas, alrededor de 25 especies son denominadas en Perú “sangre de grado” y pertenecen a los subgéneros Adenophylli (seccs. Cyclostigma y Adenophylli), Geiseleria (secc. Luntia) y Quadrilobi (secc. Sampatik). La importancia de estos árboles radica principalmente en el uso medicinal del látex (exudado al cortar la corteza) por sus capacidades cicatrizantes. Sin embargo, debido a que la mayoría de especies de “sangre de grado” son cercanas taxonómicamente y fácilmente confundibles, estas son comercializadas bajo el único nombre científico de Croton lechleri, sin una identificación validada, resultando en productos probablemente no fiables en su composición (i.e., qué especie o especies son realmente usadas), con los riesgos que esto acarrea.

Publicación

Carboxymethyl kappa/iota-hybrid carrageenan doped with NH4I as a template for solid bio-electrolytes development

( 2019)

Torres, FG

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Arroyo, J

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Alvarez, R

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Rodriguez, S

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Troncoso, O

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Lopez, D

Publicación

Carboxymethyl κ/ι-hybrid carrageenan doped with NH4I as a template for solid bio-electrolytes development

(Elsevier Ltd, 2019)

Torres F.G.

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Arroyo J.

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Alvarez R.

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Rodriguez S.

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Troncoso O.

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López D.

In this study, we analyzed the contribution of NH4I and glycerol on the ionic conductivity of carboxymethyl κ/ι-hybrid carrageenan-based solid bio-electrolytes. Electrochemical impedance spectroscopy was used to assess the electrochemical properties of the developed biopolymeric films and their interfaces over a wide range of frequencies (1& Hz–7& MHz). X-ray diffractograms demonstrated the increment of the amorphous fraction in the material as the NH4I content increases, suggesting an enhancement of ion transport processes and the successful incorporation of the salt into the host matrix.

Publicación

Characterization of healthy skin with high-frequency ultrasound using quantitative ultrasound

(Pontificia Universidad Católica del Perú, 2018)

Saavedra Bazán, Ana Cecilia

Publicación

Chronic hypoxia induces modification of the N-methyl-D-aspartate receptor in rat brain

( 1996)

Pichiule P.

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Chávez J.C.

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Boero J.

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Arregui A.

Publicación

Cognitive impairment and hypertension in older adults living in extreme poverty: A cross-sectional study in Peru

(BioMed Central Ltd., 2017)

Lazo-Porras M.

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Ortiz-Soriano V.

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Moscoso-Porras M.

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Runzer-Colmenares F.M.

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Málaga G.

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Jaime Miranda J.

Publicación

Compact Invariant Sets for Global Holomorhic Foliations

(Springer Nature, 2017)

Fernandez-Perez, A

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Mol, R

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Rosas, R

We study compact invariant sets for holomorphic foliations on Stein manifold. As application, we show some dynamical properties concerning minimal sets (with singularities) of foliations and real analytic Levi-flat hypersurfaces in projective spaces.

Publicación

Computer Aided Medical Diagnosis Tool to Detect Normal/Abnormal Studies in Digital MR Brain Images

(IEEE Xplore, 2014)

Gutierrez-Caceres, J

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Portugal-Zambrano, C

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Beltran-Castanon, C

This work presents a model to support medical diagnosis through the classification of abnormality normality in medical brain images, in order to help to specialist as a previous step in the brain pathology diagnosis. Our proposal was incorporated into a content-based image retrieval system, thus we developed a useful tool for radiologists. The first step produces the features vector of MR image using Gabor Filter for the data train and test, then as second step features vector of training data are indexed into CBIR module. The third step makes the training of SVM and as four step the test dataset is classified with the SVM trained. Finally, the result of classification are presented with a set of similar images product of a KNN query. This model was implemented as a software tool with graphical interface. We obtained 94.12% of correct classification. Our medical image dataset is composed of 187 MRI images collected from a medical diagnosis company and selected by medical specialist. The result shows that the proposed model is robust and effective as a software tool to aid support to medical diagnostic.

Publicación

Construcción de superficies equipotenciales gravitatorias para satélites sel sistema global de navegación por satélite (GNSS)

(Universidad Nacional de Ingeniería, 2016)

Chévez Abanto, Leonardo José

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Chévez Abanto, Leonardo José

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