University of Pamplona

About: University of Pamplona is a education organization based out in Pamplona, Colombia. It is known for research contribution in the topics: Population & Foreign language. The organization has 1951 authors who have published 1700 publications receiving 9156 citations. The organization is also known as: UP.

The role of the multi-drug resistance 1, p53, b cell lymphoma 2, and bcl 2-associated X genes in the biologic behavior and chemotherapeutic resistance of canine transmissible venereal tumors.

Abstract: BACKGROUND Canine transmissible venereal tumors (CTVTs) generally have different cytomorphologic subtypes and phases of progression. Some tumors have variable biologic behavior including a progressive increase in tumor aggressiveness and variable responses to chemotherapy. This behavior is partially due to high p-glycoprotein expression by tumor cells, which leads to the expulsion of chemotherapeutic drugs. Other possible causes include changes in pro- and anti-apoptotic genes from the BCL-2 family and DNA repair systems, which are associated with the p53 gene family. OBJECTIVES We aimed to determine the relative expression of the multi-drug resistance 1 (MDR1), p53, b-cell lymphoma 2 (BCL2), and bcl 2-associated X (BAX) genes in CTVT before and after therapy and establish a relationship with treatment responses, cytomorphologic patterns, and tumor progression identified with histopathology. METHODS RT-qPCR was performed on 21 CTVT tumor samples before and after initiating chemotherapy to determine specific gene expression. Normal canine testicular tissue was used as a negative control for all experiments. RESULTS MDR1 expression was decreased before and after initiating vincristine therapy in CTVT tumor tissues compared with normal canine testicular tissue; p53 and BAX were overexpressed at both time points compared with normal tissue, and no statistical differences were seen between the different morphologic types. However, BAX expression was decreased in the group with quick therapeutic responses but was still overexpressed compared with normal testicular tissue. In the group with the slowest chemotherapeutic responses, BCL2 was overexpressed. CONCLUSION The findings of this study showed a relative increase in MDR1 gene expression in response to chemotherapy and higher expression in plasmacytoid CTVTs compared with the other cytomorphologic patterns. BCL2 overexpression was related to a favorable prognosis, and p53, BAX, and BCL2 were expressed independent of the cytomorphologic CTVT type. All of the genes were expressed independent of tumor progression, as noted on histopathology.

Pseudonym change strategy based on the reputation of the neighbouring vehicles in VANETs

Abstract: Pseudonym change schemes have been studied in VANETs to guarantee the property of untraceability of the vehicles. This paper proposes a new condition based on the assumption that if there are no malicious vehicles around when a synchronous change triggers, there is no risk of tracking, and the pseudonym change defers until a time threshold. Thus, our proposal based on a synchronous strategy to increase the anonymity set, adds to the change condition, the checking of the reputation status of the neighbouring vehicles. The reputation status is the result of discretizing the reputation score of the vehicles and it is part of the periodically broadcast beacon messages. The proposal was evaluated through simulations using a real scenario. The results showed an optimization in the use of pseudonyms maintaining similar anonymity levels with other schemes.

Enhanced nanoscopy of individual CsPbBr3 perovskite nanocrystals using dielectric sub-micrometric antennas

Abstract: We demonstrate an efficient, simple, and low-cost approach for enhanced nanoscopy in individual green emitting perovskite (CsPbBr3) nanocrystals via TiO2 dielectric nanoantenna. The observed three- to five-fold emission enhancement is attributed to near-field effects and emission steering promoted by the coupling between the perovskite nanocrystals and the dielectric sub-micrometric antennas. The dark-field scattering configuration is then exploited for surface-enhanced absorption measurements, showing a large increase in detection sensitivity, leading to the detection of individual nanocrystals. Due to the broadband spectral response of the Mie sub-micrometric antennas, the method can be easily extended to electronic transitions in other spectral regions, paving the way for absorption nanoscopy of many different quantum emitters from organic molecules to quantum dots.We demonstrate an efficient, simple, and low-cost approach for enhanced nanoscopy in individual green emitting perovskite (CsPbBr3) nanocrystals via TiO2 dielectric nanoantenna. The observed three- to five-fold emission enhancement is attributed to near-field effects and emission steering promoted by the coupling between the perovskite nanocrystals and the dielectric sub-micrometric antennas. The dark-field scattering configuration is then exploited for surface-enhanced absorption measurements, showing a large increase in detection sensitivity, leading to the detection of individual nanocrystals. Due to the broadband spectral response of the Mie sub-micrometric antennas, the method can be easily extended to electronic transitions in other spectral regions, paving the way for absorption nanoscopy of many different quantum emitters from organic molecules to quantum dots.

Increase in post-thaw viability by adding seminal plasma proteins to Sanmartinero and Zebu sperm

Abstract: Summary Background: cryopreservation decreases sperm viability by approximately 50%. Objective: the objective of this study was to determine the effect of the addition of seminal plasma proteins on post-thawing sperm viability in Sanmartinero and Zebu semen. Methods: semen samples from 10 bulls of each breed were used, and seminal plasma was subjected to two-dimensional electrophoresis to establish the relationship between the relative amount of each protein spot and sperm viability. Then, seminal plasma was subjected to exclusion chromatography to separate the fraction containing these proteins. This fraction was added in doses of 0.5, 1.0, 1.5 and 2.0 mg, to 1 x 106. Sperm was thawed and incubated at 37 °C for 1 h to determine its effect on postthaw viability. Sperm were frozen using two media (citrate-fructose-yolk and Bioxcell®). Results: we found one protein spot (16.20 kDa, PI 5.5) in Sanmartinero seminal plasma that correlated (r = 0.64 p Conclusions: these results show that seminal plasma proteins decrease cryopreservation damage in sperm. The effect depends on the cryoprotectant dose as well as the breed of bull. Key words: creole bulls, cryopreservation, proteins, seminal quality, sperm membrane. Resumen Antecedentes : la criopreservacion disminuye la viabilidad espermatica por debajo del 50%. Objetivo: el objetivo de esta investigacion fue determinar el efecto de la adicion de proteinas del plasma seminal sobre la viabilidad espermatica post-descongelacion de semen de toros Sanmartinero y Cebu. Metodos : se colecto semen de 10 toros de cada raza, y el plasma seminal se sometio a electroforesis bidimensional, para establecer la relacion entre la cantidad relativa de cada punto de proteina y la viabilidad espermatica. Identificados dichos puntos, el plasma seminal se sometio a cromatografia de exclusion para separar la fraccion que contenia estas proteinas. Esta se adiciono en dosis de 0,5, 1,0, 1,5 y 2,0 mg, a muestras de 1 x 106 espermatozoides, descongelados e incubados a 37 °C durante 1 hora, para determinar su efecto en la viabilidad post-descongelacion. Los espermatozoides se congelaron usando dos medios (citrato-fructosa-yema y Bioxcell®). Resultados : se encontro un punto de proteina (16,20 kDa, punto Isoelectrico 5,5) en plasma de toros Sanmartinero, que correlaciono (r = 0,64 p Conclusiones : los resultados anteriores demuestran que las proteinas del plasma seminal disminuyen el dano en los espermatozoides por la criopreservacion, y que el efecto de estas proteinas depende del medio de congelacion, la dosis adicionada y la raza de los toros. Palabras clave: calidad seminal, criopreservacion, membrana espermatica, proteinas, toros criollos. Resumo Antecedentes : a criopreservacao diminui a viabilidade espermatica abaixo de um 50%. Objetivo: o objetivo desta pesquisa foi determinar o efeito da adicao de proteinas do plasma seminal na viabilidade espermatica pos-descongelamento de semen de touros das racas Sanmartinero y Zebu. Metodos: coletou-se semen de 10 touros de cada raca, as amostras do plasma seminal foram submetidas a eletroforese bidimensional, para estabelecer a relacao entre a quantidade relativa de cada ponto de proteina e a viabilidade espermatica. Ao serem identificados os pontos, o plasma seminal tambem foi submetido ao processo de cromatografia por exclusao para separar a fracao que continha as proteinas. A fracao foi adicionada nas doses de 0,5, 1,0, 1,5 y 2,0 mg, amostras de 1 x 106 espermatozoides, em descongelamento e incubados a temperatura de 37 °C durante 1 hora, para determinar o efeito na viabilidade pos-descongelamento. Os espermatozoides foram congelados utilizando dois meios (Citrato- frutose-gema e Bioxcell®). Resultados: encontrou-se um ponto de proteina (16,20 kDa, ponto Isoeletrico 5,5) no plasma de touro Sanmartinero, que correlacionou (r=0,64 p Conclusoes: os anteriores resultados demonstram que as proteinas do plasma seminal diminuem o dano nos espermatozoides pela criopreservacao e que o efeito destas proteinas depende do meio de congelacao, a dose adicionada e a raca dos touros. Palavras chave: criopreservacao, membrana espermatica, proteinas, qualidade seminal, touros mesticos.

MODELO DE PROPAGACIÓN EN LAS CIUDADES DE MÉRIDA (VENEZUELA) Y CÚCUTA (COLOMBIA) PARA REDES WLAN, OPERANDO EN 2.4 GHz, EN AMBIENTES EXTERIORES

Abstract: Resumen: A pesar de que en la literatura se reportan numerosos trabajos relacionados con modelos de propagacion desarrollados para prediccion de cobertura en la banda no licenciada de redes inalambricas de datos de 2,4 GHz, tanto en ambientes interiores como en ambientes exteriores, ninguno de ellos se refiere a condiciones de propagacion (morfologia, topografia, propiedades atmosfericas, entre otras) tipicas de Venezuela o similares. En este sentido, en el presente articulo se desarrolla un modelo para ambientes exteriores, basado en mediciones realizadas en las ciudades de Merida (Venezuela) y Cucuta (Colombia), ciudad esta con caracteristicas de propagacion similares a algunas ciudades de Venezuela, tal como San Cristobal. El modelo obtenido presenta un mejor desempeno, en terminos del error relativo, que los modelos de la literatura con los que fue comparado.