481 research outputs found

    Simultaneous effect of irradiance and temperature on biochemical composition of the microalga Pavlova lutheri

    Get PDF
    The biochemical composition of microalgae can be modulated through the environmental conditions prevailing during growth. The simultaneous effects of irradiance and temperature on the biochemical composition of Pavlova lutheri were evaluated using an experimental star factorial design. Five levels were tested for each parameter (temperature, 10, 14, 18, 22 and 26°C; irradiance, 60, 105, 150, 195 and 240 μmol photons m−2 s−1), whereas the carbohydrate, protein, lipid, pigments and elementary compound contents were measured as response variables. Additionally, in order to rapidly measure parameters to define the status of the culture, the validation of the relationships between biochemical parameters and physiological status were estimated through regression analysis. It was observed that irradiance and temperature play a major role in the determination of the biochemical composition of microalgae. Their effects are synergistic, and it can be observed that a trend in behaviour at a certain temperature can be reversed at a different temperature; therefore, when selecting the environmental conditions to a culture they must be studied in a combined fashion. Although there are consistent relationships between pigment contents and elementary compounds in cells, its linearity is influenced by the irradiance of the culture and its age; therefore, they can only be applied in specific circumstances. On the other side, population biomass was well estimated in terms of carotenoid content, irrespective of the environmental conditions provided and the growth phase

    The chromosomal constitution of spermatozoa from eight normal, healthy brazilian men

    Get PDF
    Apresenta-se a análise citogenética de cromossomos de espermatozóides de oito homens brasileiros normais, utilizando-se a técnica de fertilização heteróloga homemhamster. Os resultados obtidos são semelhantes aos descritos em outros laboratórios que dominam esta técnica. Obteve-se freqüência de 5.4% (variação de 1.0-13.5%) de aberrações cromossômicas, sendo 1.4% de aberrações estruturais (variação de 0.0-3.3%), freqüência de hiper-haploidia de 2.0% (variação entre 0.0-5.1%) e freqüência de hipo-haploidia de 5.6% (variação de 0.0-11.3%). A diferença entre as proporções de espermatozóides X (54.1%) e Y (45.9%) foi significativa, ao nível de 5%.We describe the chromosomal analyses of sperm from eight normal brazilian men using the human sperm-hamster egg fusion technique. The frequency of total chromosomal aberrations was 5.4% (range, 1.0-13.5%), of structural aberrations 1.4% (range, 0.0-3.3%), of hyperhaploidy 2.0% (range, 0.0-5.1%) and of hipohaploidy 5.6% (range,0.0-11.3%). The proportion of X-bearing (54.1%) and Y-bearing (45.9%) spermatozoa differed significantly at 5% level. The results obtained in this work are similar to those reported in the literature

    Characterization of desmodesmus pleiomorphus isolated from a heavy metal-contaminated site: biosorption of zinc

    Get PDF
    Microalgae have been proven efficient biological vectors for heavy metal uptake. In order to further study their biosorption potential, a strain of Desmodesmus pleiomorphus (L) was isolated from a strongly contaminated industrial site in Portugal. Under different initial Zn2? concentrations, metal removal by that strain reached a maximum of 360 mg Zn/g biomass after 7 days, at 30 mg Zn/l, after an initial rapid phase of uptake. Comparative studies were carried out using a strain of the same microalgal species that is commercially available (ACOI 561): when exposed to 30 mg Zn/l, it could remove only 81.8 mg Zn/g biomass. Biosorption experiments using inactivated biomass of the isolated strain reached a maximum Zn2? uptake of 103.7 mg/g. Metal removal at various initial pH values was studied as well; higher removal was obtained at pH 5.0. The microalga strain L, isolated from the contaminated site, exhibited a much higher removal capacity than the commercial strain, and the living biomass yielded higher levels of metal removal than its inactivated form

    Design and Optimization of Microbial Fuel Cells and Evaluation of a New Air-Breathing Cathode Based on Carbon Felt Modified with a Hydrogel—Ion Jelly®

    Get PDF
    Funding Information: This research was funded by Fundação para a Ciência e a Tecnologia projects DSAIPA/DS/0117/2020, UIDB/04565/2020, and UIDP/04565/2020, by the Associate Laboratory Institute for Health and Bioeconomy—i4HB project LA/P/0140/2020. This work was supported by the Associate Laboratory for Green Chemistry—LAQV financed by national funds from FCT/MCTES (UIDB/50006/2020). We also thank Fundação para a Ciência e Tecnologia (FCT) for funding (SFRH/BD/77568/2011 (R.N.L.C.); SFRH/BPD/80293/2011 (R.M.A.)). C.M.C. acknowledges FCT for the Ciência 2008 Program; S.V.R. acknowledges the financial support from FCT (Portuguese Foundation for Science and Technology) for a postdoctoral research grant (FRH/BPD/33864/2009). This work was supported by the Associate Laboratory for Green Chemistry—LAQV, financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020); the Institute for Bioengineering and Biosciences—iBB, financed by FCT (UID/BIO/04565/2013); and from Programa Operacional Regional de Lisboa 2020 (Project N. 007317). Publisher Copyright: © 2023 by the authors.The increased demand for alternative sustainable energy sources has boosted research in the field of fuel cells (FC). Among these, microbial fuel cells (MFC), based on microbial anodes and different types of cathodes, have been the subject of renewed interest due to their ability to simultaneously perform wastewater treatment and bioelectricity generation. Several different MFCs have been proposed in this work using different conditions and configurations, namely cathode materials, membranes, external resistances, and microbial composition, among other factors. This work reports the design and optimization of MFC performance and evaluates a hydrogel (Ion Jelly®) modified air-breathing cathode, with and without an immobilized laccase enzyme. This MFC configuration was also compared with other MFC configuration performances, namely abiotic and biocathodes, concerning wastewater treatment and electricity generation. Similar efficiencies in COD reduction, voltage (375 mV), PD (48 mW/m2), CD (130 mA/m2), and OCP (534 mV) were obtained. The results point out the important role of Ion Jelly® in improving the MFC air-breathing cathode performance as it has the advantage that its electroconductivity properties can be designed before modifying the cathode electrodes. The biofilm on MFC anodic electrodes presented a lower microbial diversity than the wastewater treatment effluent used as inocula, and inclusively Geobacteracea was also identified due to the high microbial selective niches constituted by MFC systems.publishersversionpublishe

    Estudo de caso da gestão de filas em uma unidade de saúde

    Get PDF
    Na área da saúde, é de extrema importância que o atendimento e tratamento do utente seja efetivo, sobretudo executado com rapidez. Com o crescimento da população, as pessoas buscam mais os serviços de saúde, o que afeta a oferta de serviços, profissionais e impacta no tempo de espera. Este estudo foi motivado pelo interesse em otimizar a gestão de filas numa unidade de saúde do distrito de Bragança, visando reduzir os tempos de espera para a realização de serviços médicos, garantindo que o utente seja atendido com qualidade, de forma ética e humana, e com alto nível técnico dos profissionais. O objetivo é reduzir o elevado tempo de espera que os utentes encontram ao solicitarem atendimento na unidade de saúde.info:eu-repo/semantics/publishedVersio

    Differences in the genotype frequencies of genes related to blood pressure regulation - a comparative study between South-West Europe and Peri-equatorial Africa

    Get PDF
    Background: Since the emergence of the genus Homo, hominids have occupied a wide variety of environments, facing different selective pressures. Objectives: The aim this study is to compare genotype frequencies between South-West Europe and Peri-equatorial Africa in genes potentially modulators of blood pressure. Methods: The analyzed sample consisted of 325 individuals from Portugal and 226 individuals from Africa (48 from Mo zambique and 178 from São Tomé and Príncipe). The following genetic variants were analyzed: intron 4 VNTR in eNOS, rs1050829 in G6PD, -3.7kb α-thalassemic deletion in HBA, rs1800457 in CYB5R3, Hp 1/2 genotype/phenotype in Hp and intron 16 I/D in ACE. Results: Frequencies of genotypes with the 4a allele in eNOS (p<0.001), the G allele in G6PD (p<0.001), the α-3.7 kb in HBA (p <0.001), the C allele in the CYB5R3 (p<0.001) were higher in Peri-equatorial Africa. The Hp 1.1 genotype of Hp has a higher frequency in Peri-equatorial Africa (p=0.002). ACE shows no significant differences. Conclusion: Results show differences in five genetic variants. Conditions of extreme heat and humidity, characteristic of Peri-equatorial Africa, have been associated with increased sodium loss. This study suggests that selected compensatory mechanisms printed in the genome, are nowadays risk factors for hypertension in Peri-equatorial Africa.Financial support - Instituto de Investigação Científica Bento da Rocha Cabralinfo:eu-repo/semantics/publishedVersio

    Chemical abundances of Seyfert 2 AGNs, II: N2 metallicity calibration based on SDSS

    Get PDF
    We present a semi-empirical calibration between the metallicity (Z) of Seyfert 2 active galactic nuclei and the N2 = log([N II]λ6584/H a) emission-line intensity ratio. This calibration was derived through the [OIII]λ5007/[O II]λ3727 versus N2 diagram containing observational data and photoionization model results obtained with the CLOUDY code. The observational sample consists of 463 confirmed Seyfert 2 nuclei (redshift z ≤ 0.4) taken from the Sloan Digital Sky Survey DR7 data set. The obtained Z-N2 relation is valid for the range 0.3 ≤ (Z/Z⊙) ≤ 2.0 that corresponds to -0.7 ≤ (N2) ≤ 0.6. The effects of varying the ionization parameter (U), electron density and the slope of the spectral energy distribution on the Z estimations are of the order of the uncertainty produced by the error measurements of N2. This result indicates the large reliability of our Z -N2 calibration. A relation between U and the [OIII]/[O II] line ratio, almost independent of other nebular parameter, was obtained.Fil: Carvalho, S.P.. Universidade Do Vale Do Paraiba; BrasilFil: Dors, O. L.. Universidade Do Vale Do Paraiba; BrasilFil: Cardaci, Monica Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Hägele, Guillermo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Krabbe, Nora Cristina. Universidade Do Vale Do Paraiba; BrasilFil: Pérez Montero, E.. Instituto de Astrofísica de Andalucía; EspañaFil: Monteiro, A.F.. Universidade Do Vale Do Paraiba; BrasilFil: Armah, M.. Universidade Do Vale Do Paraiba; BrasilFil: Freitas Lemes, P.. Universidade Do Vale Do Paraiba; Brasi

    Tackling Food Insecurity in Cabo Verde Islands: The Nutritional, Agricultural and Environmental Values of the Legume Species

    Get PDF
    Legume species are important food sources to reduce hunger and deal with malnutrition; they also play a crucial role in sustainable agriculture in the tropical dry islands of Cabo Verde. To improve the knowledge of the heritage of plant genetic resources in this Middle Income Country, this study had three main goals: (i) to provide a checklist of food legumes; (ii) to investigate which species are traded in local markets and, based on field surveys, to compare species for their chemical, phenolic, antioxidant, and nutritional composition; and (iii) to discuss the agronomic value and contribution to food security in this archipelago. Our results revealed that 15 species are used as food and 5 of them are locally traded (Cajanus cajan, Lablab purpureus, Phaseolus lunatus, Phaseolus vulgaris, and Vigna unguiculata). The role of these species as sources of important minerals, antioxidants, and nutritional components for food security is highlighted, and the native ones (Lablab purpureus and Vigna unguiculata) stand-out as particularly well-adapted to the climate of these islands, which are already experiencing the adverse effects of climate change. We conclude that the sustainable use of these genetic resources can contribute to the reduction of hunger and poverty, thus meeting some challenges of the Sustainable Development Goals.info:eu-repo/semantics/publishedVersio

    Specific Bioelectrical Impedance Vector Analysis Identifies Body Fat Reduction after a Lifestyle Intervention in Former Elite Athletes

    Get PDF
    Background: specific bioelectrical impedance vector analysis (BIVA) has been proposed as an alternative bioimpedance method for evaluating body composition. This investigation aimed to verify the ability of specific BIVA in identifying changes in fat mass after a 16-week lifestyle program in former athletes. Methods: The 94 participants included in the Champ4life project (clinicaltrials.gov: NCT03031951) were randomized into intervention (n = 49) and control (n = 45) groups, from which 82 athletes completed the intervention (age 43.9 ± 9.2 y; body mass index 31.1 ± 4.6 kg/m2). Fat mass was estimated by dual-energy X-ray absorptiometry. Bioelectric resistance, reactance, phase angle, and vector length were assessed by bioelectric impedance spectroscopy, and the BIVA procedure was applied. Results: A significant (p &lt; 0.05) group x time interaction for fat mass, specific resistance, reactance, and vector length was found. Fat mass and vector length significantly (p &lt; 0.05) decreased in the intervention group, while no change was measured in the control group. Considering the participants as a whole group, changes in vector length were associated with changes in fat mass percentage (r2 = 0.246; β = 0.33; p &lt; 0.001) even after adjusting for age, sex, and group (R2 = 0.373; β = 0.23; p = 0.002). Conclusions: The specific BIVA approach is suitable to track fat mass changes during an intervention program aimed to reduce body fat in former athletes
    • …
    corecore