Formation of valine microcrystals through rapid antisolvent precipitation

In this work we have experimentally studied concentration effects on antisolvent precipitation of valine (an amino acid) from aqueous isopropanol solutions. Our experiments showed that the valine precipitation is very sensitive to both the supersaturation and to the water content in the final solution. Results from spectrophotometric measurements and supersaturation analysis showed that the crystal formation kinetics are strongly dependent on both mixing and concentration profiles in the early stages of the process, even though no visible change in the systems occurs immediately upon mixing with the antisolvent or subsequent dilution. Results from small-angle static light scattering measurements showed that the first visible crystals are of micron size and they grow only little over time, while their number increases gradually. Taken together, these experiments point to intermediate phase separation of (possible amorphous) precursors, being either very small nanoparticles or droplets with their refractive index closely matching that of the continuous phase, which subsequently assemble into micron size valine crystals

The impact of transnational activities of Colombian migrants living in the US on the sending country's socioeconomic development

PhD ThesisThis research aims to determine, analyse and understand the impact of transnational activities carried out by Colombian migrants living in the US on the socioeconomic development of the country of origin at the micro level of the household, the meso level of the community and the macro level of the nation. Additionally, the role the Colombian government has adopted towards its migrants and their transnationalism has also been examined in order to provide recommendations for future policy action to reduce the cost of migration and enhance its benefits for the country in general. The research recognises the importance of considering diverse levels of analysis (De Haas, 2012), and of including both agency and structure (De Haas, 2007a) when studying the link between migration and development. To accomplish this, New Economics of Labour Migration (NELM) and Transnationalism approaches have been used as a conceptual basis of the thesis. The thesis applies a qualitative methodology, namely multiple case studies, to gain a deep understanding of transnationalism and its impact. It discusses the transnational activities of Colombian migrants, including the reasons behind their engagement or the lack thereof and the impact those activities could have at the three levels of analysis proposed. The main data collection method used was focus groups with semi-structured open-ended questions with migrant families, and interviews with context-oriented actors, including three governmental officials and two experts on Colombian migration. Other sources of data included conference participation, review of previous studies, publicly available data and statistics, and governmental public information, among others. The research has adopted a multidisciplinary approach, employing concepts from international business, management, economics and sociology. The analysis of the data collected and its association with the literature has allowed to establish that Colombian migrants living in the US do engage in some transnational activities, especially those individually oriented. However, collective transnational activities such as political participation, and community remittances, have shown to have a low level of engagement. The personal characteristics of the migrant and the 3 structures in both the sending and receiving countries have influenced migrants’ willingness to get involved in transnational activities. The involvement at diverse levels and frequency in transnational activities creates various impacts at the household, community and national level. Those impacts seem to be mainly beneficial for households, while more diverse outcomes can be observed at the community and national levels. Therefore, migrants’ transnationalism by itself cannot be considered a tool that could reduce the North-South dependence in the case of Colombia; the impacts of those activities in the country of origin point towards both increasing and decreasing the development gap between both countries. Individual migrants conduct a number of international activities through which they exercise their agency, within the limitations imposed upon them by the structures of the place of origin and destination. At the same time, those structures are shaped by transnationalism and the impact migrants’ activities could generate. However, migrant activity impact on socioeconomic development will not reduce the development gap as long as the country of origin does not provide the right environment to support local development. The Colombian government, on the other hand, has made some efforts to include its migrants within national projects, and has recently aimed to include them not only as a political force but also as economic agents. Nonetheless, most of the strategies used are limited in scope, and therefore their impacts are limited too. To enhance the potential positive impact of transnationalism on the socioeconomic development of the community and the country a number of recommendations have been provided in this research, recognising that local development is not dependent on the migrant but on governments and their institutions. Finally, migration as a family strategy and transnational activities provide migrants’ families with livelihood improvements, as explained by the approaches of NELM and Transnationalism, while the community and the country are impacted in both positive and negative ways. The challenge for communities and governments is to design the right strategies to reduce the negative impacts migration and transnationalism can generate while enhancing their potential benefits. All those strategies must be developed taking into account migrant profile and the structure of the place of origin and destination.Universidad EAFIT and Colciencia

Agro-Ecological Zoning for Tall Wheatgrass (Thinopyrum Ponticum) as a Potential Energy and Forage Crop in Salt-Affected and Dry Lands of Argentina

Thinopyrum ponticum, is the most disseminated halophyte speciescultivated for forage on hydro-halomorphic soils in the world. Theobjective of the present work was to identify the geographicareas fordevelopment of tall wheatgrass on halomorphic soils in Argentina, for forageand as feedstock for bioenergy. To define the agroclimate in Argentina, we considered the thermal and hydric limits of the species in its place of originand in locations where it is successfully cultivated around the world. The maps corresponding to the bioclimatic indices were drawn using a GIS, andthe map obtained by overlaying them defined the agroclimatic suitability. Thiszoning was finally superimposed on the drylands saline and alkaline soils inthecountry, thus defining the agro-ecological suitability of Argentina forthis species under different moisture regimes: moist-subhumid,dry-subhumid, semiarid to arid climate. The the agro-ecological zoning showsthe potential growing areas for tall wheatgrass in Argentina on soils withhalomorphism processes under dry climates.Fil: Falasca, Silvia Liliana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Miranda del Fresno, Ma. Carolina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Humanas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pitta-alvarez, Sandra Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentin

ENTHALPY EU PROJECT: ENABLING THE DRYING PROCESS TO SAVE ENERGY AND WATER, REALISING PROCESS EFFICIENCY IN THE DAIRY CHAIN

The EU funded ENTHALPY project aims to significantly reduce the consumption of water and energy in milk powder production to increase efficiency in the dairy production chain. Using a systematic approach, ENTHALPY project focusses on innovations within the post-harvest chain representing the highest energy and water consumption such as RF heating, solar thermal energy, mono-disperse atomising, dryer modelling, inline monitoring, enzymatic cleaning and membrane technology

Cultural Preservation of Ethnomedicine in Peru

In conjunction with the Minority Health & Health Disparities International Research Training program at San Diego State University, three Linfield students contributed to the ongoing Peru Ethnomedical Project in Trujillo, Peru by: Conducting surveys in two neighborhoods on the edge of the city; Creating a medicinal plant garden in the Chan Chan archaeological site museum. Surveys conducted in Moche, Trujillo were part of a larger study supervised by anthropologists Douglas Sharon and Thomas Love. The research aims to evaluate the usage of medicinal plants in rural and urban Peruvian communities. Linfield’s contribution focused on the creation of the medicinal garden to serve as a community model and educational program. The overall purpose of the 2015 summer faculty collaborative project was to: Preserve the knowledge of these practices; Analyze the plant properties; Publish the information; Provide the community with a garden that reflects the commonly used plants; Educate new generations; Bring back and apply this knowledge in the Linfield community

Programa didáctico de convivencia escolar y prevención del bullying en estudiantes de educación primaria de una institución educativa estatal - Chiclayo

La investigación se orientó a determinar la influencia de un programa didáctico de convivencia para prevenir el bullying en los alumnos del sexto grado “B” de una institución educativa Primaria de Chiclayo. La investigación es de tipo cuantitativa, cuasi experimental con diseño pre test- post test. El instrumento utilizado se construyó considerando los fundamentos teóricos de la convivencia y del bullying y fue sometido a una validación de contenido por expertos. A partir de los resultados obtenidos en el pretest se deduce que la mayoría de estudiantes presentan problemas en la convivencia, manifestada en agresiones, físicas directas e indirectas, lo que conlleva a desarrollar un programa didáctico para prevenir situaciones de bullying. Los resultados del post test muestran que el programa aplicado al grupo experimental influyó positivamente obteniendo como resultados que más del 80% de alumnos mejoraron en las relaciones interpersonales, manifestando una mejora en sus relaciones interpersonales y disminuyendo las actitudes de agresividad de manera significativa. Finalmente los problemas de convivencia escolar mejoraron en las agresiones físicas directas e indirectas

Hormone deprivation alters mitochondrial function and lipid profile in the hippocampus

Mitochondrial dysfunction is a common hallmark in aging. In the female, reproductive senescence is characterized by loss of ovarian hormones, many of whose neuroprotective effects converge upon mitochondria. The functional integrity of mitochondria is dependent on membrane fatty acid and phospholipid composition, which are also affected during aging. The effect of long-term ovarian hormone deprivation upon mitochondrial function and its putative association with changes in mitochondrial membrane lipid profile in the hippocampus, an area primarily affected during aging and highly responsive to ovarian hormones, is unknown. To this aim, Wistar adult female rats were ovariectomized or sham-operated. Twelve weeks later, different parameters of mitochondrial function (O2 uptake, ATP production, membrane potential and respiratory complex activities) as well as membrane phospholipid content and composition were evaluated in hippocampal mitochondria. Chronic ovariectomy reduced mitochondrial O2 uptake and ATP production rates and induced membrane depolarization during active respiration without altering the activity of respiratory complexes. Mitochondrial membrane lipid profile showed no changes in cholesterol levels but higher levels of unsaturated fatty acids and a higher peroxidizability index in mitochondria from ovariectomized rats. Interestingly, ovariectomy also reduced cardiolipin content and altered cardiolipin fatty acid profile leading to a lower peroxidizability index. In conclusion, chronic ovarian hormone deprivation induces mitochondrial dysfunction and changes in the mitochondrial membrane lipid profile comparable to an aging phenotype. Our study provides insights into ovarian hormone loss-induced early lipidomic changes with bioenergetic deficits in the hippocampus that may contribute to the increased risk of Alzheimer’s disease and other age-associated disorders observed in postmenopause.Fil: Zarate, Sandra Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Astiz, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Magnani, Natalia Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Imsen, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Merino, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Alvarez, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Reines, Analia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Seilicovich, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; Argentin

Sonic hedgehog lineage in the mouse hypothalamus: from progenitor domains to hypothalamic regions

<p>Abstract</p> <p>Background</p> <p>The hypothalamus is a brain region with essential functions for homeostasis and energy metabolism, and alterations of its development can contribute to pathological conditions in the adult, like hypertension, diabetes or obesity. However, due to the anatomical complexity of the hypothalamus, its development is not well understood. <it>Sonic hedgehog </it>(<it>Shh</it>) is a key developmental regulator gene expressed in a dynamic pattern in hypothalamic progenitor cells. To obtain insight into hypothalamic organization, we used genetic inducible fate mapping (GIFM) to map the lineages derived from <it>Shh-</it>expressing progenitor domains onto the four rostrocaudally arranged hypothalamic regions: preoptic, anterior, tuberal and mammillary.</p> <p>Results</p> <p><it>Shh-</it>expressing progenitors labeled at an early stage (before embryonic day (E)9.5) contribute neurons and astrocytes to a large caudal area including the mammillary and posterior tuberal regions as well as tanycytes (specialized median eminence glia). Progenitors labeled at later stages (after E9.5) give rise to neurons and astrocytes of the entire tuberal region and in particular the ventromedial nucleus, but not to cells in the mammillary region and median eminence. At this stage, an additional <it>Shh</it>-expressing domain appears in the preoptic area and contributes mostly astrocytes to the hypothalamus. <it>Shh-</it>expressing progenitors do not contribute to the anterior region at any stage. Finally, we show a gradual shift from neurogenesis to gliogenesis, so that progenitors expressing Shh after E12.5 generate almost exclusively hypothalamic astrocytes.</p> <p>Conclusions</p> <p>We define a fate map of the hypothalamus, based on the dynamic expression of <it>Shh </it>in the hypothalamic progenitor zones. We provide evidence that the large neurogenic <it>Shh-</it>expressing progenitor domains of the ventral diencephalon are continuous with those of the midbrain. We demonstrate that the four classical transverse zones of the hypothalamus have clearly defined progenitor domains and that there is little or no cell mixing between the tuberal and anterior or the preoptic and anterior hypothalamus. Finally, we show that, in the tuberal hypothalamus, neurons destined for every mediolateral level are produced during a period of days, in conflict with the current 'three-wave' model of hypothalamic neurogenesis. Our work sets the stage for a deeper developmental analysis of this complex and important brain region.</p

Treatment of saline produced water through photocatalysis using rGO-TiO 2 nanocomposites

Graphene like-TiO2 nanocomposites (rGO-TiO2) are prepared via hydrothermal route by following different synthetic protocols. The as-prepared nanostructured materials exhibit higher photocatalytic activity than bare TiO2 in the treatment of synthetic produced water containing high salinity levels and different compositions of recalcitrant dissolved organic matter. The effect of the preparation method on the physico-chemical properties is assessed by performing a wide characterization combining different analyses, such as nitrogen physic-adsorption (BET), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), UV-VIS Diffuse Reflectance Spectroscopy (DRUV) and Electron Paramagnetic Resonance (EPR). The effect of several operative variables (i.e., TiO2/rGO weight ratios, and addition of hydrogen peroxide) on the photocatalytic activity is also critically evaluated. The highest photocatalytic activity is obtained for a rGO/TiO2 weight ratio of about 10%, for which a good compromise between uniformity of dispersion of the TiO2 particles on the rGO layers and covering degree of the titania photoactive surface is achieved. This study can contribute to open new perspectives in the design of high performance graphene like-based TiO2 photocatalysts for removing hydrophobic bio-recalcitrant pollutants from saline water.Peer ReviewedPostprint (author's final draft