Structure evolution of nanodiamond aggregates: a SANS and USANS study

Ultra-small-angle neutron scattering (USANS) and small-angle neutron scattering (SANS) measurements, covering length scales from micrometres to nanometres, were made to investigate the structure of nanodiamonds (NDs) and their suspensions. These nanodiamonds were produced by two different techniques, namely by the detonation method and by the laser ablation of a carbon-hydrocarbon mixture. The (U)SANS results indicated the presence of structures four orders of magnitude larger than the dimensions of a single ND particle, consisting of aggregations of ND particles. This aggregation of the ND particles was studied by employing the contrast variation technique. Two different solvents, namely H2O and dimethyl sulfoxide (and their deuterated counterparts), were used to understand the role of hydrogen in the shape and size of the aggregates. The analysis of experimental data from SANS measurements also reveals the ND particles to have an ellipsoidal structure. Using a defined shape model and the SANS contrast variation technique, it was possible to characterize the non-diamond outer shell of the particles and determine the outer layer thickness. This clarification of the structure of the NDs will allow better preparation of suspensions/samples for various applications. Understanding the structure of NDs at multiple length scales also provides crucial knowledge of particle-particle interaction and its effect on the aggregation structures

The Environment of the Malnourished Child

capítulo de libro -- Universidad de Costa Rica, 1976The study of the relation of man to his environment in developing countries emphasizes the inevitable need for societies to recognize the true causes of infection, malnutrition, and poverty. The need is for improvement in the quality of human life in less developed nations, a recommendation easy to prescribe but difficult to accomplish. Although our pool of knowledge is incomplete, it is adequate to suggest ways to diminish infection, increase food production, utilize food more efficiently, improve education, and provide systems of justice to protect the classes most in need. The physical environment in tropical and subtropical regions, and the socioeconomic characteristics of the population inhabiting such regions, favor maintenance and transmission of a variety of viruses, bacteria, and parasites that make agricultural progress and social development difficult, and that contribute to poor fetal growth, nutrient wastage, and deficient postnatal physical growth. accounting for most of the childhood morbidity and mortality. In this regard. infections contribute indirectly to the overall food problem in a similar fashion as pests do in terms of food losses and spoilage. The overall effect could be comparable or greater than that resulting from an inadequate capacity to produce or to purchase the food needed. Thus, my objective has been to stress, within the whole environment, the importance of infection and the need to diminish it. Waysto control and prevent infection are readily known. They have to do with education of the population to improve personal and environmental hygiene. Economic investment is necessary to improve housing and water supply sYstems, waste disposal, and such preventive measures as immunization programs. Although such measures may appear expensive when first implemented, they have long-lasting effects and many require minimal expenditure once they are established. Large segments of the population stand to benefit, and other development interventions can then be introduced. However, these measures should not be implemented singly. They should be accompanied by community development, family planning, social legislation-in other words, the holistic approach to health and welfare. To do otherwise may aggravate the problem by stimulating demographic growth, perpetuating malnutrition and infection, and maintaining underdevelopmentUniversidad de Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Sexual Size Dimorphism and Body Condition in the Australasian Gannet

Funding: The research was financially supported by the Holsworth Wildlife Research Endowment. Acknowledgments We thank the Victorian Marine Science Consortium, Sea All Dolphin Swim, Parks Victoria, and the Point Danger Management Committee for logistical support. We are grateful for the assistance of the many field volunteers involved in the study.Peer reviewedPublisher PD

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

A Small Genomic Region Containing Several Loci Required for Gastrulation in Drosophila

Genetic screens in Drosophila designed to search for loci involved in gastrulation have identified four regions of the genome that are required zygotically for the formation of the ventral furrow. For three of these, the genes responsible for the mutant phenotypes have been found. We now describe a genetic characterization of the fourth region, which encompasses the cytogenetic interval 24C3-25B, and the mapping of genes involved in gastrulation in this region. We have determined the precise breakpoints of several existing deficiencies and have generated new deficiencies. Our results show that the region contains at least three different loci associated with gastrulation effects. One maternal effect gene involved in ventral furrow formation maps at 24F but could not be identified. For a second maternal effect gene which is required for germ band extension, we identify a candidate gene, CG31660, which encodes a G protein coupled receptor. Finally, one gene acts zygotically in ventral furrow formation and we identify it as Traf4

Direct multiplex imaging and optogenetics of Rho GTPases enabled by near-infrared FRET

Direct visualization and light control of several cellular processes is a challenge, owing to the spectral overlap of available genetically encoded probes. Here we report the most red-shifted monomeric near-infrared (NIR) fluorescent protein, miRFP720, and the fully NIR Forster resonance energy transfer (FRET) pair miRFP670-miRFP720, which together enabled design of biosensors compatible with CFP-YFP imaging and blue-green optogenetic tools. We developed a NIR biosensor for Rac1 GTPase and demonstrated its use in multiplexed imaging and light control of Rho GTPase signaling pathways. Specifically, we combined the Rac1 biosensor with CFP-YFP FRET biosensors for RhoA and for Rac1-GDI binding, and concurrently used the LOV-TRAP tool for upstream Rac1 activation. We directly observed and quantified antagonism between RhoA and Rac1 dependent on the RhoA-downstream effector ROCK; showed that Rac1 activity and GDI binding closely depend on the spatiotemporal coordination between these two molecules; and simultaneously observed Rac1 activity during optogenetic manipulation of Rac1.Peer reviewe

Selected Schizosaccharomyces pombe Strains Have Characteristics That Are Beneficial for Winemaking

At present, wine is generally produced using Saccharomyces yeast followed by Oenococus bacteria to complete malolactic fermentation. This method has some unsolved problems, such as the management of highly acidic musts and the production of potentially toxic products including biogenic amines and ethyl carbamate. Here we explore the potential of the fission yeast Schizosaccharomyces pombe to solve these problems. We characterise an extensive worldwide collection of S. pombe strains according to classic biochemical parameters of oenological interest. We identify three genetically different S. pombe strains that appear suitable for winemaking. These strains compare favourably to standard Saccharomyces cerevisiae winemaking strains, in that they perform effective malic acid deacidification and significantly reduce levels of biogenic amines and ethyl carbamate precursors without the need for any secondary bacterial malolactic fermentation. These findings indicate that the use of certain S. pombe strains could be advantageous for winemaking in regions where malic acid is problematic, and these strains also show superior performance with respect to food safety