The Universidad Nacional de Colombia , also called UNAL or just UN, is a public, national, coeducational, research university, located primarily in Bogotá, Medellín, Manizales and Palmira, Colombia. Established in 1867 by an act of the Congress of Colombia, the university is the largest higher education institution of the country with more than 44,000 students, the largest number of graduated professionals per year, and number of academic programmes at undergraduate and postgraduate levels, with 423 academic programmes, which includes 94 graduate diplomas, 61 Academic specializations, 38 medical specialties, 131 Master's degrees, and 46 doctorates. It is also one of the few universities that employs post-doctorate fellows in the country. Approximately 40,000 students are studying for an undergraduate degree and 4,000 for a graduate degree.The university is a member of the Association of Colombian Universities , the Iberoamerican Association of Postgraduate Universities , and the Iberoamerican University Network Universia. Along with Antioquia and Valle universities, it conforms what is known as the Golden Triangle of higher education in Colombia, being among the most selective and competitive universities in the country. A study by Universia found it to be the Colombian university producing the largest number of scientific papers published in peer-refereed publications in 2005, and the 45th most prolific in Latin America. Furthermore, according to the Latinamerican Web Ranking of Universities, the National University of Colombia ranked in the first place of the country in internet presence, and among the first universities in the region. Regarding the CIVETS universities, the National University occupied the fifth place.The institution offers a wide selection of programmes in both undergraduate and graduate levels, such as medicine, nursing, dentistry, engineering, chemistry, pharmacy, mathematics, physics, geology, biology, psychology, social science, arts , philosophy, and law. Wikipedia.
National University of Colombia | Date: 2017-05-24
The present invention relates to a diluent for the protection, preservation and cryopreservation of semen. The diluent contains at least one cytoprotective compound derived from isopropylphenol along with cryoprotective agents and coadjuvants that allow for increased sperm motility, vitality and functionality. The presence of isopropylphenols in the diluent of the present invention reduces the oxidative stress on semen by inhibiting the production of reactive oxygen species and by inhibiting lipid peroxidation. The diluent of the invention is very effective in the protection of sperm when they are placed under highly stressful conditions, such as cryopreservation.
Agency: European Commission | Branch: FP7 | Program: CP-FP-SICA | Phase: ENV.2011.1.1.5-1 | Award Amount: 4.76M | Year: 2011
AMAZALERT will enable raising the alert about critical feedbacks between climate, society, land-use change, vegetation change, water availability and policies in Amazonia. We will: 1) analyze and improve coupled models of global climate and Amazon, land use, vegetation and socio-economic drivers to quantify anthropogenic and climate induced land-use and land cover change and non-linear, irreversible feedbacks among these components 2) assess the role of regional and global policies and societal responses in the Amazon region for altering the trajectory of land-use change in the face of climate change and other anthropogenic factors and finally 3) propose i) an Early Warning System for detecting any imminent irreversible loss of Amazon ecosystem services, ii) policy response strategies to prevent such loss. We first prioritise the functions of Amazonia and threats to these. We then will analyse uncertainties in biogeochemistry, land cover (vegetation), land-use change and regional hydrology , as well as nonlinear responses and feedbacks using existing and new simulations from state of the art models in which land surface is coupled to global climate. The way in which policies and possible future response strategies of policy makers, trade and economy will affect land-use change will be modelled. This will lead to (A) understanding the impact on and effectiveness of a range of international and regional policy options, including REDD\; and (B) identification of both biophysical and socio-economic indicators of irreversible change. AMAZALERT integrates the multidisciplinary knowledge and research of world-renowned, highly influential climate, land cover, land use change scientists and also policy analysts from 14 European and South-American institutions that have been collaborating for 10 to 30 years. Thus, this project can achieve maximum impact on EU (2020 climate goals), international and South-American strategies, including REDD
Agency: European Commission | Branch: FP7 | Program: CP | Phase: ENV.2013.6.3-3 | Award Amount: 11.33M | Year: 2014
The project eartH2Observe brings together the findings from European FP projects DEWFORA, GLOWASIS, WATCH, GEOWOW and others. It will integrate available global earth observations (EO), in-situ datasets and models and will construct a global water resources re-analysis dataset of significant length (several decades). The resulting data will allow for improved insights on the full extent of available water and existing pressures on global water resources in all parts of the water cycle. The project will support efficient and globally consistent water management and decision making by providing comprehensive multi-scale (regional, continental and global) water resources observations. It will test new EO data sources, extend existing processing algorithms and combine data from multiple satellite missions in order to improve the overall resolution and reliability of EO data included in the re-analysis dataset. The usability and operational value of the developed data will be verified and demonstrated in a number of case-studies across the world that aim to improve the efficiency of regional water distribution. The case-studies will be conducted together with local end-users and stakeholders. Regions of interest cover multiple continents, a variety of hydrological, climatological and governance conditions and differ in degree of data richness (e.g. the Mediterranean and Baltic region, Ethiopia, Colombia, Australia, New Zealand and Bangladesh). The data will be disseminated though an open data Water Cycle Integrator portal to ensure increased availability of global water resources information on both regional and global scale. The data portal will be the European contributor to the existing GEOSS water cycle platforms and communities. Project results will be actively disseminated using a combination of traditional methods (workshops, papers, website and conferences) and novel methods such as E-learning courses and webinars that promote the use of the developed dataset.
University of Valencia and National University of Colombia | Date: 2013-10-30
A microscope, method and computer program for obtaining quantitative phase images by digital holographic microscopy. The microscope includes: a coherent light source (1) and a beam splitter (3) for generating an object beam (Lo) for illuminating a sample, and a reference beam (Lr); an optical system with a main optical path making up a telecentric afocal system, and a reference optical path; and recording means (12) recording a hologram of said sample in the image plane of the optical system. The method includes recording a hologram in the image plane of an optical telecentric afocal system. The computer program is adapted for implementing part of the steps of the method.
Lemeshko V.V.,National University of Colombia
Biochimica et Biophysica Acta - Biomembranes | Year: 2014
The simplest mechanism of the generation of the mitochondrial outer membrane potential (OMP) by the VDAC (voltage-dependent anion channel)-hexokinase complex (VHC), suggested earlier, and by the VDAC-glucokinase complex (VGC), was computationally analyzed. Even at less than 4% of VDACs bound to hexokinase, the calculated OMP is high enough to trigger the electrical closure of VDACs beyond the complexes at threshold concentrations of glucose. These results confirmed our previous hypothesis that the Warburg effect is caused by the electrical closure of VDACs, leading to global restriction of the outer membrane permeability coupled to aerobic glycolysis. The model showed that the inhibition of the conductance and/or an increase in the voltage sensitivity of a relatively small fraction of VDACs by factors like tubulin potentiate the electrical closure of the remaining free VDACs. The extrusion of calcium ions from the mitochondrial intermembrane space by the generated OMP, positive inside, might increase cancer cell resistance to death. Within the VGC model, the known effect of induction of ATP release from mitochondria by accumulated glucose-6-phosphate in pancreatic beta cells might result not only of the known effect of GK dissociation from the VDAC-GK complex, but also of a decrease in the free energy of glucokinase reaction, leading to the OMP decrease and VDAC opening. We suggest that the VDAC-mediated electrical control of the mitochondrial outer membrane permeability, dependent on metabolic conditions, is a fundamental physiological mechanism of global regulation of mitochondrial functions and of cell death. © 2014 Elsevier B.V.
Garcia-Sucerquia J.,National University of Colombia
Optics Letters | Year: 2012
Color digital lensless holographic microscopy with micrometer resolution is presented. Multiwavelength illumination of a biological sample and a posteriori color composition of the amplitude images individually reconstructed are used to obtain full-color representation of the microscopic specimen. To match the sizes of the reconstructed holograms for each wavelength, a reconstruction algorithm that allows for choosing the pixel size at the reconstruction plane independently of the wavelength and the reconstruction distance is used. The method is illustrated with experimental results. © 2012 Optical Society of America.
Perez-Quintero A.L.,National University of Colombia
BMC plant biology | Year: 2010
BACKGROUND: microRNAs (miRNAs) are non-coding short RNAs that regulate gene expression in eukaryotes by translational inhibition or cleavage of complementary mRNAs. In plants, miRNAs are known to target mostly transcription factors and are implicated in diverse aspects of plant growth and development. A role has been suggested for the miRNA pathway in antiviral defense in plants. In this work, a bioinformatics approach was taken to test whether plant miRNAs from six species could have antiviral activity by targeting the genomes of plant infecting viruses. RESULTS: All plants showed a repertoire of miRNAs with potential for targeting viral genomes. The viruses were targeted by abundant and conserved miRNA families in regions coding for cylindrical inclusion proteins, capsid proteins, and nuclear inclusion body proteins. The parameters for our predicted miRNA:target pairings in the viral genomes were similar to those for validated targets in the plant genomes, indicating that our predicted pairings might behave in-vivo as natural miRNa-target pairings. Our screening was compared with negative controls comprising randomly generated miRNAs, animal miRNAs, and genomes of animal-infecting viruses. We found that plant miRNAs target plant viruses more efficiently than any other sequences, but also, miRNAs can either preferentially target plant-infecting viruses or target any virus without preference. CONCLUSIONS: Our results show a strong potential for antiviral activity of plant miRNAs and suggest that the miRNA pathway may be a support mechanism to the siRNA pathway in antiviral defense.
National University of Colombia | Date: 2014-01-28
The present invention discloses a reaction system for producing fatty-acid alkyl esters using packed reactors, particularly liquid-film reactors, with a countercurrent feed current flow scheme based on the alcoholysis of oils and fats, specifically the methanolysis of palm oil and soya oil. The reaction system comprises a descending liquid-film reactor that uses as semi-structured packing for generating an interface area. The reactor is fed, separately, with the oil or fat, through the bottom of the reactor, and a mixture containing alcohol, glycerol and catalyst, which may be fed in in an intermediate stage. It is also possible, optionally, to feed in a second stream of the mixture of alcohol, glycerol and catalyst in proportions different from those of the first stream, either in an intermediate stage of the reactor or through the top thereof. The products, a mixture of fatty-acid alkyl esters, alcohol and catalyst, and another of glycerol, alcohol and catalyst, exit via the top and the bottom of the reactor, respectively. The volumetric fraction of packing in the reactor is between 2 and 50%, the operating temperature between 25 C. and 180 C., depending on the alcohol used, the molar ratio of alcohol to oil or fat between 3:1 and 10:1, and it is possible for the catalyst to be any homogeneous basic catalyst used in alcoholysis, such as CH3OK, NaOH, KOH, or mixtures thereof, in a proportion of between 0.5% and 3% by weight with respect to the oil flow. The conversion and the yield of the liquid-film reactor operated countercurrentwise, in a single reaction step, are greater than 99.7% and 99.9%, respectively.
National University of Colombia | Date: 2014-08-15
The invention relates to an orthodontic tool for the placement, positioning and attaching of brackets using a direct or indirect method, said tool comprising two parts: a body for manipulating the device (1) and a point (2). The shape of the body (1) is compatible with the hand and offers the user control and comfort when arranging the bracket (100) on the targetthe target being the mesiodistal centre of the dental piece or toothat a predetermined height (202), resulting in precision and accuracy.
National University of Colombia and Empresas Publicas De Medellin E.S.P. | Date: 2014-03-04
The present invention discloses a method for the detection and diagnosis of faults in running electric machines. The method consists of: i) simultaneously obtaining a current signal and a voltage signal associated with the rotor winding of the electric machine; ii) defining a group of vectors whose components are DC and/or AC values at different separation and amplification levels of the current and voltage signals; iii) simultaneously obtaining a current signal and a voltage signal associated with an emulated fault; iv) defining a group of vectors whose components are DC and/or AC values at different separation and amplification levels of the current and voltage signals associated with an emulated fault; v) determining the variations in the components of the vectors; vi) comparing the vectors that show component variations with the emulated fault vectors; vii) analyzing the variations and comparisons in order to detect whether or not there is at least one type of fault; and viii) reporting the presence or absence of at least one type of fault in the electric machine. The present invention also discloses a system to carry out this method, consisting of: i) a unit that obtains the current and voltage signals associated with the winding of the electric machine; ii) a unit that emulates faults; iii) a unit that sensitizes the signals by separating the DC and/or AC levels and amplifies the resulting signal; iv) a memory unit that stores the DC and/or AC values; and v) a unit that processes, analyzes and reports on the status of the machine.