429 research outputs found
Social Research Collaboration: Libraries Need Not Apply?
Social media was born an efficient method of personal networking. As more and more researchers took to social media platforms, we have witnessed an organic growth of collaboration among scholars, faculty, students, etc. This phenomenon has led us to a profound change in the way we conduct research through social media. Research through collaboration is now increasingly important in order to achieve a higher impact throughout the research community. But where does the library fit into this? The simple answer is that researchers are now bypassing the library.
This presentation will look at the new reality of social research collaboration and discuss what kinds of webbased tools can support the workflow and peer collaboration of researchers. The presenters will also discuss why it is essential for libraries to become part of the solution before they are left out in the cold
Nivel de Empleabilidad en la Municipalidad de San Borja y San Juan de Lurigancho, Lima 2019
La presente tesis de maestría tuvo como objetivo general determinar los niveles de empleabilidad en los trabajadores de la Municipalidad de San Borja y San Juan de Lurigancho, Lima 2019. La investigación fue de tipo básica, descriptiva y correlacional con un enfoque cuantitativo, diseño no experimental y transversal y un método hipotético deductivo. Para el presente estudio, la población está conformada por 100 empleados pertenecientes a la Municipalidad de San Borja y Municipalidad de San Juan de Lurigancho, de los cuales se consideraron a 65 trabajadores de cada entidad. Estos instrumentos fueron validados por expertos conocedores del tema. Luego de realizar el análisis estadístico adecuado, los resultados arrojaron que no existe diferencia del nivel de Empleabilidad de trabajadores de la Municipalidad de San Borja y San Juan de Lurigancho, Lima 2019 según el valor de significancia es mayor al nivel de significancia lo que permite determinar que existe evidencia estadística donde indica que no existe alta diferencia en el nivel de empleabilidad de ambas entidades
Water uptake and transport in lianas and co-occurring trees of a seasonally dry tropical forest
Water uptake and transport were studied in eight liana species in a seasonally dry tropical forest on Barro Colorado Island, Panama. Stable hydrogen isotope composition (δD) of xylem and soil water, soil volumetric water content (θv), and basal sap flow were measured during the 1997 and 1998 dry seasons. Sap flow of several neighboring trees was measured to assess differences between lianas and trees in magnitudes and patterns of daily sap flow. Little seasonal change in θv was observed at 90–120 cm depth in both years. Mean soil water δD during the dry season was −19‰ at 0–30 cm, −34‰ at 30–60 cm, and −50‰ at 90–120 cm. Average values of xylem δD among the liana species ranged from –28‰ to –44‰ during the middle of the dry season, suggesting that water uptake was restricted to intermediate soil layers (30–60 cm). By the end of the dry season, all species exhibited more negative xylem δD values (–41‰ to –62‰), suggesting that they shifted to deeper water sources. Maximum sap flux density in co-occurring lianas and trees were comparable at similar stem diameter (DBH). Furthermore, lianas and trees conformed to the same linear relationship between daily sap flow and DBH. Our observations that lianas tap shallow sources of soil water at the beginning of the dry season and that sap flow is similar in lianas and trees of equivalent stem diameter do not support the common assumptions that lianas rely primarily on deep soil water and that they have higher rates of sap flow than co-occurring trees of similar stem size
A role for antizyme inhibitor 2 in the biosynthesis and content of serotonin and histamine in mouse mast cells
Polyamines (putrescine, spermidine and spermine; PAs) are essential for the majority of living cells. Antizymes and antizyme inhibitors are key regulatory proteins of PA levels by affecting ornithine decarboxylase and PA uptake. In addition to PAs, mast cells (MC) synthesize and store in their granules histamine (Hia) and serotonin (5-HT), which are critical for their function. Our previous studies have indicated a metabolic interplay among PAs, Hia and 5-HT in this cell type. For instance, we showed that PAs affect Hia synthesis during early stages of IL-3-induced bone marrow cell differentiation into bone marrow derived MCs (BMMCs) and demonstrated that PAs are present in MC secretory granules and are important for granule homeostasis, including Hia storage and 5-HT levels. A few years ago, a novel antizyme inhibitor (AZIN2) was described whose expression is restricted to a few tissues and cell types including brain, testis and MCs. In MCs, it was recently proposed that AZIN2 could act as a local regulator of PA biosynthesis in association with 5-HT-containing granules and with 5-HT release following MC activation. To gain insight into the role of AZIN2 in the biosynthesis and storage of 5-HT and also Hia, we have generated BMMCs from both wild-type and transgenic mice with severe Azin2 hypomorphism, and have analyzed the content of PAs, 5-HT and Hia, and some elements of their metabolisms. Spermine and 5-HT levels were reduced in Azin2 hypomorphic BMMCs compared with wild-type controls, whereas the amount of Hia was increased. Accordingly, the level of tryptophan hydroxylase 1 (the key enzyme for 5-HT biosynthesis) was reduced and the amount of enzymatic activity of histidine decarboxylase (the enzyme responsible for Hia biosynthesis) was increased in Azin2 hypomorphic BMMCs. Taken together, our results show evidence that AZIN2 has an important role in the regulation of 5-HT and Hia biosynthesis and storage in MCsUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work was supported by SAF2011-26518 (MINECO, Spain) and P10-CVI-6585 and Bio-267 (Junta de Andalucia, Spain). CIBERER is an iniciative of Instituto de Salud Carlos III (Spain)
A role for antizyme inhibitor 2 in the biosynthesis and content of histamine and serotonin in mouse mast cells
Polyamines (putrescine, spermidine and spermine; PAs) are required for the survival of the majority of living cells. Antizymes and antizyme inhibitors are key regulatory proteins of PA levels by affecting ornithine decarboxylase, the rate-limiting biosynthetic enzyme, and PA uptake. In addition to PA, mast cells (MC) synthesize and store in their granules the biogenically active amines histamine (Hia) and serotonin (5-HT), which are of critical importance for their function. Previously, we have performed several studies in this cell type regarding the interplay between the metabolisms of PAs and Hia and 5-HT. Our results showed that PAs affect Hia synthesis during early stages of IL-3-induced bone marrow cell differentiation into bone marrow derived MCs (BMMCs) and demonstrated that PAs are present in MC secretory granules and are important for granule homeostasis, including Hia storage and 5-HT levels. A few years ago, a novel antizyme inhibitor (AZIN2) was described. In contrast to AZIN1, AZIN2 expression is restricted to a few tissues and cell types including brain, testis and MCs. In MCs, it was recently described that AZIN2 could act as a local regulator of PA biosynthesis in association with the 5-HT granule content and release. At present, our aim is to gain further insight into the role of AZIN2 in the biosynthesis, storage and release of both Hia and 5-HT. In this study, we have generated BMMCs from both wild-type and transgenic mice with severe Azin2 hypomorphism, and have analyzed the content of PAs, Hia and 5-HT, and some elements of their metabolisms. Both PAs and 5-HT levels were reduced in Azin2 hypomorphic BMMCs compared with wild-type controls, whereas the amount of Hia was increased. Accordingly, the level of tryptophan hydroxylase 1 (the key enzyme for 5-HT biosynthesis) was reduced and the amount of enzymatic activity of histidine decarboxylase (the enzyme responsible for histamine biosynthesis) was increased in Azin2 hypomorphic BMMCs. Taken together, our results show evidence that AZIN2 has an important role in the regulation of Hia and 5-HT biosynthesis and storage in MCs.
Department of Molecular Biology and Biochemistry, and CIBER de Enfermedades Raras (CIBER-ER), Faculty of Sciences, University of Málaga, Málaga 29071, Spain. Corresponding author: I. Fajardo ([email protected])
This work was supported by SAF2011-26518 (MINECO, Spain) and P10-CVI-6585 and Bio-267 (Junta de Andalucia, Spain). CIBERER is an iniciative of Instituto de Salud Carlos III (Spain).Universidad de Málaga. Campus de Excelencia Internacional Andalucía-Tech. SAF2011-26518 (MINECO, Spain) and P10-CVI-6585 and Bio-267 (Junta de Andalucia, Spain. CIBERER is an iniciative of Instituto de Salud Carlos III (Spain)
Pb(II) binding to humic substances: an equilibrium and spectroscopic study
The binding of Pb(II) to humic acids is studied through an approach combining equilibrium and spectroscopic measurements. The methods employed are potentiometric and fluorometric titrations, fluorescence excitation−emission matrices (EEM) and IR spectroscopy. Potentiometric titration curves are analyzed using the NICA equations and an electrostatic model treating the humic particles as an elastic polyelectrolyte network. EEMs are analyzed using parallel factor analysis, decomposing the signal in its independent components and finding their dependence on Pb(II) activity. Potentiometric results are consistent with bimodal affinity distributions for Pb(II) binding, whereas fluorometric titrations are explained by monomodal distributions. EEM analysis is consistent with three independent components in the humic fluorescence response, which are assigned to moieties with different degree of aromaticity. All three components show a similar quenching behavior upon Pb(II) binding, saturating at relatively low Pb(II) concentrations. This is attributed to metal ion induced aggregation of humic molecules, resulting in the interaction between the aromatic groups responsible for fluorescence; this is also consistent with IR spectroscopy results. The observed behavior is interpreted considering that initial metal binding (observed as strongly binding sites), correspond to bi- or multidentate complexation to carboxylate groups, including binding between groups of different humic molecules, promoting aggregation; further metal ions (observed as weakly binding sites) bind to single ligand groups.Fil: Orsetti, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de Los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires; ArgentinaFil: Marco Brown, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de Los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires; ArgentinaFil: Andrade, Estela M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de Los Materiales, Medioambiente y Energía; ArgentinaFil: Molina, Fernando Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de Los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires; Argentin
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A novel approach for the production and purification of mannosylerythritol lipids (MEL) by Pseudozyma tsukubaensis using cassava wastewater as substrate
P. tsukubaensis is a yeast-like microorganism that synthesized the biosurfactant mannosylerythritol lipids-B (MEL-B). Production cost can be one of the drawbacks of biosurfactants production. Therefore the development of efficient and cost effective purification strategies and the use of by-products in the culture medium could serve as important strategies to reduce overall process cost. The aim of this work was to evaluate the production of MEL using cassava wastewater, a hydrophilic medium composed of a low-cost substrate which is a by-product of cassava processing, followed by foam fractionation and ultrafiltration of MEL . Cassava wastewater proved to be a feasible culture medium for P. tsukubaensis and MEL-B production as the yield (1.26 g L) was similar to that reported by others using water-soluble carbon sources (up to 2 g/L). Interestingly ultrafiltration with 100 KDa MWCO memabranes (using 20 mL centrifugal devices) led to the purification of MEL-B in one step since ≈ 80% of MEL was recovered, while more than 95% of proteins were found in the permeate. The scale up of the ultrafiltration (up to 500 mL) using a cross flow filtration unit led to very similar results. Overall the ultrafiltration led to a threefold increase in MEL purity in terms of protein (at both scales). The chemical characterisation by NMR confirmed the production of MEL-B homologue and also the production of a second stereoisomer ≈ 9%, while the CG-MS and MALDI-TOFMS analysis confirmed the main fatty acids within the structure of MEL-B ( C8:0 and 12:0 and C8:0 and C14:1) . Therefore, the process developed here was found to be a good alterntative to the conventional production of MEL which uses synthetic culture medium, solvent extraction (ethyl acetate) and column chromatography (silica) for its purification
Structural and functional interaction between polyamine related molecules and biological membranes
La comunicación describe el conocimiento actual sobre las interacciones de biomoléculas relacionadas con el metabolismo de poliaminas con las estructuras y funciones de las membranas biológicasChanges induced by PA on nucleic acid (NA) conformation and synthesis is proven to be a major reason for PA essentiality (1-3). However, PA interactions with other polyanions, for instance polyanionic membrane lipid bilayers and glyosaminoglycans have received less attention (3-4). The functional importance of these interactions still is an obscure but interesting area of cell and molecular biology, especially in mammalian cells for which specific PA transport systems are not fully characterized (5). In mammals, activity and turnover of the polyamine (PA) synthesis key enzyme is controlled by a set of proteins: Antizymes (OAZ1-3) and antizyme inhibitors (AZIN1 and 2). It is demonstrated that AOZ modulate polyamine uptake (6), and that PA transport to mitochondria is linked to the respiratory chain state and modulates mitochondrial permeability transition (7). Antizyme expression variants have been located in mitochondria, being proposed as a proapoptotic factor (7-8). AZIN 2 is only expressed in a reduced set of tissues that includes mast cells, where it is associated to mast cell granules membrane (9). This fact, together to the abnormalities observed in bone marrow derived mast cell granules when they are differentiated under restricted PA synthesis conditions (10 and unpublished results), point out to important roles of PA and their related proteins in structure and function of mast cell granules. We will also present novel biophysical results on tripartite interactions of PA that remark the interest of the characterization of PA interactions with lipid bilayers for biomedicine and biotechnology.
Thus, the information reported in this paper integrates previously reported information with our still unpublished results, all indicating that PA and their related proteins also are important factors for structure and dynamics of biological membranes and their associated functions essential in human physiology; for instance, solute interchange with the environment (uptake and secretion), oxidative metabolism and apoptosis. The importance of these involved processes for human homeostasis claim for further research efforts.
1. Ruiz-Chica J, Medina MA, Sánchez-Jiménez F and Ramírez FJ (2001) Fourier Transform Raman study of the structural specificities on the interaction between DNA and biogenic polyamines. Biophysical J. 80:443-454.
2. Lightfoot HL, Hall J (2014) Endogenous polyamine function--the RNA perspective. Nucleic Acids Res. 42:11275-11290.
3. Igarashi K, Kashiwagi K (2010) Modulation of cellular function by polyamines. Int J Biochem Cell Biol. 42:39-51.
4. Finger S, Schwieger C, Arouri A, Kerth A, Blume A (2014) Interaction of linear polyamines with negatively charged phospholipids: the effect of polyamine charge distance. Biol Chem. 395:769-778.
5. Poulin R, Casero RA, Soulet D. (2012) Recent advances in the molecular biology of metazoan polyamine transport. Amino Acids. 42:711-723.
6. Kahana C (2009) Regulation of cellular polyamine levels and cellular proliferation by antizyme and antizyme inhibitor. Essays Biochem. 4:47-61.
7. Agostinelli E, Marques MP, Calheiros R, Gil FP, Tempera G, Viceconte N, Battaglia V, Grancara S, Toninello A (2010) Polyamines: fundamental characters in chemistry and biology. Amino Acids 38:393-403.
8. Liu GY, Liao YF, Hsu PC, Chang WH, Hsieh MC, Lin CY, Hour TC, Kao MC, Tsay GJ, Hung HC (2006) Antizyme, a natural ornithine decarboxylase inhibitor, induces apoptosis of haematopoietic cells through mitochondrial membrane depolarization and caspases' cascade. Apoptosis 11:1773-1788.
9. Kanerva K, Lappalainen J, Mäkitie LT, Virolainen S, Kovanen PT, Andersson LC (2009). Expression of antizyme inhibitor 2 in mast cells and role of polyamines as selective regulators of serotonin secretion. PLoS One 31:e6858.
10. García-Faroldi G, Rodríguez CE, Urdiales JL, Pérez-Pomares JM, Dávila JC, Pejler G, Sánchez-Jiménez F, Fajardo I (2010) Polyamines are present in mast cell secretory granules and are important for granule homeostasis. PLoS One 30:e15071.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Mobile App Prototype for Course Management in Secondary Education
In the last decade, mobile applications have shown an expansion to a great diversity of uses that can be made, which has influenced at different levels (economic, cultural, political), as in the area of learning where it has played a very important role in learning, since now with the development of technologies, children and adolescents are very interested in these new technologies and it is easier for them to use them, which also supports them in learning a great diversity of subjects of their own interest. That is why in this work a prototype of a mobile application for the management of mobile education using the Scrum methodology at the Norbert Wiener University of Lima-Peru, knowing that there are learning problems in students in the classroom, for this, want to provide a mobile application that supports the student to improve their learning. As a result, obtained from the study, was a prototype of a mobile application to improve learning in the Monte Carmelo private school in Lima-Peru, where a virtual model of the mobile application is shown, register the user, login where you can view their classes and share their class assignments, facilitating the user to enter their class and study material, this was achieved using balsamiq, the Scrum methodology with its four phases. The results of the survey conducted to the experts show that in most of the questions they gave a high scale, with the highest average of 4.91 with a standard deviation of 0.302 and only one low scale obtained of 1.45 on average with a standard deviation of 0.52
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