638 research outputs found
Effect of Season and Year of Evaluation in the Selection of \u3cem\u3eBrachiaria humidicola\u3c/em\u3e Hybrids
Brachiaria humidicola is well adapted to infertile and acid soils with poor drainage or temporary flooding (Keller-Grein et al. 1996). It is widely used in Brazil in wetlands and areas of marginal land characterised by waterlogged soils. During the evaluation stages of the breeding program of this species, genotypes are generally tested using consecutive cuts within different seasons for at least 2 years. The ‘Cerrado’ region, where most animal production takes place in Brazil, has 2 well defined seasons: spring-summer with warm weather and rain; and autumn-winter with cooler, dry weather. Thus, owing to environmental variation, especially related to climate, it is important to investigate the main effects of environmental factors (years and seasons), as well as interactions between genotypes and environmental factors in order to have greater confidence in the selection of superior hybrids of B. humidicola on the basis of agronomic and nutritional traits
Sewage sludge fertilization—A case study of Sweet Potato yield and heavy metal accumulation
Sewage sludge (SS) is derived from wastewater treatment plants and can be used as a
biofertilizer when properly stabilized. This work aimed to evaluate SS application for agricultural
production improvement. SS was tested on Porto Santo Island (Portugal). The experiment was
randomly designed with three 25 m2 plots for each treatment (2 SS concentrations + control without
SS) and performed in two consecutive cycles. For the first cycle, dehydrated sludge was mixed with
soil, obtaining final concentrations of 0.8 kg/m2
(C1) and 1.6 kg/m2
(C2). Half of the concentration
was used for the second cycle. Fifty-eight sweet potato plants were used in each plot. SS application
boosted the agronomic parameters of biomass, productivity, and shoot biomass. Furthermore,
improvements in soil properties were observed, mainly for pH, CEC, and NO3
-N, with no significant
increase in heavy metals. For the edible parts, heavy metal concentrations decreased, and Pb was the
only one that still exceeded the maximum limits. The results demonstrated that SS application to
low-fertility soil is effective in improving the agronomic parameters of sweet potato and enhancing
soil features. Further studies considering other variables, i.e., SS origin, soil properties, and the crop,
must be carried out to propose custom applications.info:eu-repo/semantics/publishedVersio
Management of sorghum anthracnose through diversification of genetic resistance in host population
Scaling solutions from interacting fluids
We examine the dynamical implications of an interaction between some of the
fluid components of the universe. We consider the combination of three matter
components, one of which is a perfect fluid and the other two are interacting.
The interaction term generalizes the cases found in scalar field cosmologies
with an exponential potential. We find that attracting scaling solutions are
obtained in several regions of parameter space, that oscillating behaviour is
possible, and that new curvature scaling solutions exist. We also discuss the
inflationary behaviour of the solutions and present some of the constraints on
the strength of the coupling, namely those arising from nucleosynthesis.Comment: RevTeX, 21 pages, 8 figure
Immobilization of L-asparaginase towards surface-modified carbon nanotubes
L-asparaginase (ASNase, EC 3.5.1.1) is an enzyme that catalyzes L-asparagine hydrolysis into L-aspartic acid and
ammonia and is mainly applied in pharmaceutical and food industries [1]. The ASNase currently commercialized for pharmaceutical purposes is produced from two main bacterial sources: recombinant Escherichia coli
and Erwinia chrysanthemi. However, some disadvantages are associated with its free form, such as the shorter
half-life [2]. Immobilization of ASNase has been proposed as an efficient approach to overcome this limitation
[3]. In this work, a straightforward method, including the functionalization of multi-walled carbon nanotubes
(MWCNTs) through a hydrothermal oxidation treatment with nitric acid, and the immobilization of ASNase
by adsorption over pristine and modified MWCNTs was investigated. Different operation conditions, including pH, contact time, ASNase/MWCNT mass ratio, and the operational stability of the immobilized ASNase were
evaluated. The characterization of the ASNase-MWCNT bioconjugate was addressed using different techniques,
namely Transmission Electron Microscopy (TEM), Thermogravimetric analysis (TGA), and Raman spectroscopy.
Functionalized MWCNTs showed promising results, with an immobilization yield and a relative recovered activity of commercial ASNase above 95%, under the optimized adsorption conditions (pH 8, 60 min of contact
and 1.5´10–3 g.mL-1of ASNase). The ASNase-MWCNT bioconjugate also showed improved enzyme operational
stability (6 consecutive reaction cycles without activity loss), proving its suitability for application in industrial
processes.publishe
Immobilization of L-asparaginase towards surface-modified carbon nanotubes
L-asparaginase (LA) is an enzyme that catalyzes L-asparagine hydrolysis into L-aspartic
acid and ammonia and is mainly applied in pharmaceutical and food industries. The LA
currently commercialized for pharmaceutical purposes is produced from two main
bacterial sources: recombinant Escherichia coli and Erwinia chrysanthemi. However,
some disadvantages are associated with its free form, such as the shorter half-life.
Immobilization of LA has been proposed as an efficient approach to overcome this
limitation. In this work, a straightforward method, including the functionalization of
multi-walled carbon nanotubes (MWCNTs) through a hydrothermal oxidation treatment
and the immobilization of LA by adsorption over pristine and modified MWCNTs was
investigated. Different operation conditions, including pH, contact time,
ASNase/MWCNT mass ratio, and the operational stability of the immobilized LA, were
evaluated. The characterization of the LA-MWCNT bioconjugate was addressed using
different techniques, namely Transmission Electron Microscopy (TEM),
Thermogravimetric analysis (TGA), and Raman spectroscopy. Functionalized MWCNTs showed promising results, with an immobilization yield and a relative recovered activity
of commercial LA above 95%, under the optimized adsorption conditions (pH 8, 60 min
of contact, and 1.510–3
g.mL-1
of LA). The LA-MWCNT bioconjugate also showed
improved enzyme operational stability (6 consecutive reaction cycles without activity
loss), proving its suitability for application in industrial processes.publishe
Growth variability and demographic structure of northeast Atlantic chub mackerel (Scomber colias) in southern European Atlantic waters
The Atlantic chub mackerel (Scomber colias) is one of the main fishing resources for the fisheries targeting small pelagics in NW African waters. This species is expanding its geographical distribution through higher latitudes in southern European Atlantic waters, and it has become an important fishing resource in Iberian Atlantic waters during the last decades. The present study addresses the growth variability of S. colias in the Iberian waters, from southern Bay of Biscay up to Gulf of Cadiz. Age estimates based on otoliths and growth parameters were obtained from specimens collected within the study area during one decade (from both commercial landings and scientific-acoustic surveys), and sexual growth variation was analysed. A common pattern of abundant cohorts was observed in various areas. However, differences in the demographic structure of the catches were observed among the different areas, with the southernmost area studied (Portuguese and Spanish waters off Gulf of Cadiz) standing out with younger individuals. These new findings are of interest for the stock assessment of S. colias, which has not been addressed in ICES waters so far
Superior operational stability of immobilized L-asparaginase over surface-modified carbon nanotubes
L-asparaginase (ASNase, EC 3.5.1.1) is an enzyme that catalyzes the L-asparagine hydrolysis into L-aspartic acid and ammonia, being mainly applied in pharmaceutical and food industries. However, some disadvantages are associated with its free form, such as the ASNase short half-life, which may be overcome by enzyme immobilization. In this work, the immobilization of ASNase by adsorption over pristine and modified multi-walled carbon nanotubes (MWCNTs) was investigated, the latter corresponding to functionalized MWCNTs through a hydrothermal oxidation treatment. Different operating conditions, including pH, contact time and ASNase/MWCNT mass ratio, as well as the operational stability of the immobilized ASNase, were evaluated. For comparison purposes, data regarding the ASNase immobilization with pristine MWCNT was detailed. The characterization of the ASNase-MWCNT bioconjugate was addressed using different techniques, namely Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA) and Raman spectroscopy. Functionalized MWCNTs showed promising results, with an immobilization yield and a relative recovered activity of commercial ASNase above 95% under the optimized adsorption conditions (pH 8, 60 min of contact and 1.5 × 10-3 g mL-1 of ASNase). The ASNase-MWCNT bioconjugate also showed improved enzyme operational stability (6 consecutive reaction cycles without activity loss), paving the way for its use in industrial processes.publishe
Photocatalytic ozonation of urban wastewater and surface water using immobilized TiO2 with LEDs: Micropollutants, antibiotic resistance genes and estrogenic activity
Photocatalytic ozonation was employed for the first time in continuous mode with TiO2-coated glass Raschig rings and light emitting diodes (LEDs) to treat urban wastewater as well as surface water collected from the supply area of a drinking water treatment plant (DWTP). Different levels of contamination and types of contaminants were considered in this work, including chemical priority substances (PSs) and contaminants of emerging concern (CECs), as well as potential human opportunistic antibiotic resistant bacteria and their genes (ARB&ARG). Photocatalytic ozonation was more effective than single ozonation (or even than TiO2 catalytic ozonation) in the degradation of typical reaction by-products (such as oxalic acid), and more effective than photocatalysis to remove the parent micropollutants determined in urban wastewater. In fact, only fluoxetine, clarithromycin, erythromycin and 17-alpha-ethinylestradiol (EE2) were detected after photocatalytic ozonation, by using solid-phase extraction (SPE) pre-concentration and LC-MS/MS analysis. In surface water, this treatment allowed the removal of all determined micropollutants to levels below the limit of detection (0.01-0.20 ng L(-1)). The efficiency of this process was then assessed based on the capacity to remove different groups of cultivable microorganisms and housekeeping (16S rRNA) and antibiotic resistance or related genes (intI1, blaTEM, qnrS, sul1). Photocatalytic ozonation was observed to efficiently remove microorganisms and ARGs. Although after storage total heterotrophic and ARB (to ciprofloxacin, gentamicin, meropenem), fungi, and the genes 16S rRNA and intI1, increased to values close to the pre-treatment levels, the ARGs (blaTEM, qnrS and sul1) were reduced to levels below/close to the quantification limit even after 3-days storage of treated surface water or wastewater. Yeast estrogen screen (YES), thiazolyl blue tetrazolium reduction (MTT) and lactate dehydrogenase (LDH) assays were also performed before and after photocatalytic ozonation to evaluate the potential estrogenic activity, the cellular metabolic activity and the cell viability. Compounds with estrogenic effects and significant differences concerning cell viability were not observed in any case. A slight cytotoxicity was only detected for Caco-2 and hCMEC/D3 cell lines after treatment of the urban wastewater, but not for L929 fibroblasts.info:eu-repo/semantics/acceptedVersio
Allergies and Diabetes as Risk Factors for Dengue Hemorrhagic Fever: Results of a Case Control Study
Dengue is an arboviral disease that affects large areas of countries in tropical and subtropical regions of the world. Around 500,000 cases and 22,000 deaths of dengue hemorrhagic fever (DHF)/Dengue Shock Syndrome (DSS), the most severe presentations of this disease, occur annually. It is unclear why some cases of dengue fever (0.5% to 4%) progress to DHF/DSS. There is weak evidence that some diseases could have a role in this process, such as diabetes, hypertension, and allergies. In epidemics most dengue fever cases are sent home as there are too many to be kept in observation, but if it were possible to identify those with a higher risk of progression to DHF, they could be kept for observation, for early detection of signs, symptoms and alterations in laboratory tests suggestive of DHF, to enable timely and effective clinical management and early intervention. We study this issue and we believe that the evidence produced in this study, when confirmed in other studies, suggests that screening criteria might be used to identify adult patients at a greater risk of developing DHF with a recommendation that they remain under observation and monitoring in a hospital
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