1,238 research outputs found
Strategies towards reduction of cellulases consumption: debottlenecking the economics of lignocellulosics valorization processes
Lignocellulosic residues have been receiving growing interest as a promising source of polysaccharides, which can be converted into a variety of compounds, ranging from biofuels to bioplastics. Most of these can replace equivalent products traditionally originated from petroleum, hence representing an important environmental advantage. Lignocellulosic materials are theoretically unlimited, cheaper and may not compete with food crops. However, the conversion of these materials to simpler sugars usually requires cellulolytic enzymes. Being still associated with a high cost of production, cellulases are commonly considered as one of the main obstacles in the economic valorization of lignocellulosics. This work provides a brief overview of some of the most studied strategies that can allow an important reduction of cellulases consumption, hence improving the economy of lignocellulosics conversion. Cellulases recycling is initially discussed regarding the main processes to recover active enzymes and the most important factors that may affect enzyme recyclability. Similarly, the potential of enzyme immobilization is analyzed with a special focus on the contributions that some elements of the process can offer for prolonged times of operation and improved enzyme stability and robustness. Finally, the emergent concept of consolidated bioprocessing (CBP) is also described in the particular context of a potential reduction of cellulases consumption.Biomass and Bioenergy Research Infrastructure (BBRI)-
LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitiveness and
Internationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Programme (Lisboa
2020) and by North Portugal Regional Operational Program (Norte 2020) under the Portugal 2020
Partnership Agreement, through the European Regional Development Fund (ERDF) and has been
supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the
strategic funding of UIDB/04469/2020, the MIT-Portugal Program (Ph.D. Grant PD/BD/128247/2016
to Joana Cunha) and through Project EcoTech (POCI-01-0145- FEDER-032206/ FAPESP 2018/07522-6)
funded by the European Regional Development Fund under the scope of Norte2020—Programa
Operacional Regional do Norte. The authors also acknowledge the Ph.D. fellowship of Elisa Zanuso
supported by the Mexican Science and Technology Council—Energy sustainability fund of Secretary
of Energy Mexico (CONACY-SENER) (CONACYT ID 639021/495314)info:eu-repo/semantics/publishedVersio
Reutilização de águas residuais : modelação da adsorção de nutrientes no solo
O presente estudo incide na modelação da remoção de nutrientes presentes em águas residuais domésticas por adsorção no solo e na avaliação do risco de contaminação de aquíferos por parte destes. Nesse sentido, desenvolveu-se um modelo matemático e efectuou-se a determinação experimental dos parâmetros que caracterizam as isotérmicas de adsorção dos iões nitrato, fosfato e amónio. Os resultados experimentais indicaram que o solo tem principalmente carga iónica positiva,
visto que os iões de carga contrária (tais como o nitrato e fosfato) foram os que principalmente adsorveram. Os resultados da simulação demonstraram que o fosfato é totalmente adsorvido e que a concentração de nitrato e amónio na água intersticial, após o período de um ano, é de 0.250 mg/L e
0.023 mg/L respectivamente, a 2 m de profundidade. Em relação ao exercício de simulação, estudouse o efeito de uma sobrecarga de nutrientes assim como a possibilidade de ocorrer saturação da
coluna de solo. No caso de ocorrer uma sobrecarga de nutrientes no solo proveniente da descarga de água residual com uma concentração até quatro vezes superior ao valor médio, verificou-se que a concentração do ião amónio foi a mais afectada, aumentando de 27 % a uma profundidade de 2 m e ao fim de um ano. Finalmente, os parâmetros das isotérmicas de adsorção (segundo os modelos de Freundlich e Langmuir) foram sujeitos a uma análise de sensibilidade, tendo-se comprovado que o
modelo desenvolvido é extremamente sensível à constante α da isotérmica de Freundlich
Prospective scenarios for water quality and ecological status in Lake Sete Cidades (Portugal) : the integration of mathematical modelling in decision processes
The design of alternative strategies for water and ecological quality protection at the Lake
Verde of Sete Cidades should be coupled with the assessment of future trophic states.
Therefore, a mathematical model was developed to make prospective scenarios to reduce
the risk of environmental degradation of the lake, and a modified Psenner scheme was used
to characterize P distribution in the sediments. The model was able to describe thermal
stratification, nutrient cycling (P, NH4 and NO3), dissolved O2, and phytoplankton dynamics
in the water column and adjacent sediment layers. Internal P recycling, resulting from thermal
stratification and sediment anoxia, was identified as the main cause for the increase of
P concentration in the hypolimnion followed by slow transfer to the epilimnion (about
20 lg/L annual average). Cyanobacteria blooms during spring were explained by the availability
of P and increased water temperature verified during this season. The most sensitive
model parameter was sediment porosity. This parameter has a direct effect in dissolved O2
and P profiles and also in phytoplankton biomass. Finally, different water quality restoration
scenarios were identified and their effectiveness assessed. Without the adoption of
remediation measures (scenario control), Lake Verde water quality would deteriorate with
annual average concentrations of total P and phytoplankton biomass (dry matter) reaching
34 lg/L and 2 mg/L, respectively, after 10 years of simulation. The reduction of P loads (scenario
PORAL) into the lake would improve water quality comparatively to the scenario control,
reducing the annual average concentrations of total P from 34 lg/L to 26 lg/L and of
phytoplankton from 2 mg/L down to 1.4 mg/L after 10 years of simulation. In scenario sediments,
corresponding to a decrease in the organic content of the sediments, a reduction in
the concentrations of total P and phytoplankton is expected in the first two years of simulation,
but this effect, would be attenuated throughout the years due to organic matter
sedimentation. The best strategy is obtained by combining external and internal measures
for P remediation. Finally, it is recommended that the model be used to integrate the
results of water quality monitoring and watershed management plans.Regional
Department of Water Resources and Land Planning; Regional Secretary of Environment
and Sea; Science and Technology
Foundation
High-frequencies in TESS A–F main sequence stars
The driving mechanism for high-frequency oscillations in some chemically peculiar Ap stars, the roAp stars, is not understood. The TESS data provide an ideal opportunity to extend the number of roAp stars which might provide further clues to address this problem. From an examination of over 18000 stars in TESS sectors 1–7, we have discovered high-frequency pulsations in 14 A–F stars, of which only 3 are classified as Ap stars. In addition to these new discoveries, we discuss the frequencies in 9 previously known roAp stars. In one of these stars, HD 60435, we confirm a previous finding that the pulsations have lifetimes of only a few days. In another known roAp star, HD 6532, the relative amplitudes of the rotationally-modulated sidelobes, which are generally used to estimate the inclination of the magnetic axis relative to the rotational axis, are significantly different from those found in ground-based B-band photometric observations. We also discuss 4 δ Scuti stars which appear to have independent frequencies similar to those of roAp stars
Dynamic Interdomain Network Slicing for verticals in the 5Growth project
Proceedings of: IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN), 9-11 Nov. 2021, Heraklion, Greece.This paper proposes and validates a Interdomain Network Slicing framework for verticals, allowing them to directly participate in the establishment and control of end-to-end Communication Services deployment across multiple inter-operator domains. The framework progresses the means made available by different standards and research initiatives to enhance service requesting and provisioning interfaces for the stakeholders involved, namely operators and verticals. The framework is validated under two different use cases, showcasing effective end-to-end service instantiation and a first assessment towards dynamic service modification capability.This work has been supported by EC H2020 5GPPP 5Growth project (Grant 856709)
Causes of variation in BCG vaccine efficacy: examining evidence from the BCG REVAC cluster randomized trial to explore the masking and the blocking hypotheses.
BCG protection varies and in some places (nearest the equator) is low or absent. Understanding this variation can inform the efforts to develop new vaccines against tuberculosis. Two main hypotheses are used to explain this variation: under masking, new vaccines are unlikely to increase protection; under blocking new vaccines have a greater potential to be effective when BCG is not. We conducted a cluster randomized trial to explored the masking and blocking hypotheses by studying BCG vaccine efficacy of neonatal vaccination and when administered for the first or a second (revaccination) time at school age in two sites (Manaus close and Salvador further south from the equator). Seven hundred and sixty three state schools were matched on socio economic characteristics of the neighborhood and 239,934 children were randomized to vaccine (BCG vaccination at school age) or control group. Protection by first BCG vaccination at school age was high in Salvador (34%, 95% CI 7-53%, p=0.017) but low in Manaus (8%, 95% CI t0 39-40%, p=0.686). For revaccination at school age, protection was modest in Salvador (19%, 95% CI 3-33%, p=0.022) and absent in Manaus (1%, 95% CI to 27-23%, p=0.932). Vaccine efficacy for neonatal vaccination was similar in Salvador (40%, 95% CI 22-54%, p<0.001) and Manaus (36%, 95% CI 11-53%, p=0.008). Variation in BCG efficacy was marked when vaccine was given at school age but absent at birth, which points towards blocking as the dominant mechanism. New tuberculosis vaccines that overcome or by pass this blocking effect could confer protection in situations where BCG is not protective
Trilostane treatment for feline hypercortisolism : Latin America multicenter study, 43 cases (2012-2022)
Glucagon-Like Peptide-1 Agonists Protect Pancreatic β-Cells From Lipotoxic Endoplasmic Reticulum Stress Through Upregulation of BiP and JunB
Chronic exposure of pancreatic beta-cells to saturated free fatty acids (FFAs) causes endoplasmic reticulum (ER) stress and apoptosis and may contribute to beta-cell loss in type 2 diabetes. Here, we evaluated the molecular mechanisms involved in the protection of beta-cells from lipotoxic ER stress by glucagon-like peptide (GLP)-1 agonists utilized in the treatment of type 2 diabetes.info:eu-repo/semantics/publishe
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