•A central composite design was applied to assessing the effect of selected factors.•Stability of the vine shoots-derived biochar was mainly determined by the particle size.•Using a bed of alumina ...represents a low-cost way to partly remove tar from the pyrolysis gas.
This study examines the effect of three key operating factors (peak temperature, particle size and pressure) on the potential stability of the biochar produced by slow pyrolysis of vine shoots. The following response variables were considered as key indicators of the potential stability of biochar in soils: the fixed-carbon yield, the fraction of aromatic carbon, and the molar H:C and O:C ratios. Slow pyrolysis tests were conducted in a laboratory-scale fixed-bed unit and planned according to a 2-level factorial design. The behavior of the product gas yield and composition at the outlet of the secondary cracking reactor (a fixed-bed of activated alumina particles at 700°C) was also evaluated as a function of the three factors. The results from the statistical tests revealed that the particle size is the most significant factor in determining the potential stability of biochars. Using larger particles of biomass and, in a lesser extent, operating at higher peak temperatures leads to the production of more stable materials. Unexpectedly, the absolute pressure only plays a significantly positive role in decreasing the tar content in the producer gas at the outlet of a secondary cracking reactor.
The structural plasticity of polyglutamine repeats Barbosa Pereira, Pedro José; Manso, José A.; Macedo-Ribeiro, Sandra
Current opinion in structural biology,
June 2023, 2023-Jun, 2023-06-00, 20230601, Letnik:
80
Journal Article
Recenzirano
Odprti dostop
From yeast to humans, polyglutamine (polyQ) repeat tracts are found frequently in the proteome and are particularly prominent in the activation domains of transcription factors. PolyQ is a ...polymorphic motif that modulates functional protein-protein interactions and aberrant self-assembly. Expansion of the polyQ repeated sequences beyond critical physiological repeat length thresholds triggers self-assembly and is linked to severe pathological implications. This review provides an overview of the current knowledge on the structures of polyQ tracts in the soluble and aggregated states and discusses the influence of neighboring regions on polyQ secondary structure, aggregation, and fibril morphologies. The influence of the genetic context of the polyQ-encoding trinucleotides is briefly discussed as a challenge for future endeavors in this field.
This study investigates the causality relationship between crude oil consumption and economic growth in twenty three Sub-Saharan African countries. We applied a multivariate panel Granger causality ...framework during 1985–2011 and we included crude oil price as the control variable of the model. The results indicate that in the short-run, there is a bi-directional causality relationship between crude oil consumption and economic growth in oil importing region and there is a uni-directional causality relationship from crude oil consumption to GDP in oil exporting region. However, in the long-run there is a bi-directional causality relationship between them in both regions. Therefore, reducing crude oil consumption without employing appropriate policies adversely impacts on economic growth of Sub-Saharan Africa. Hence, in order to reduce crude oil dependency of the region policymakers should pay more attention to the issue of energy efficiency programs.
► We examined Granger causality among oil consumption and GDP in Sub-Saharan Africa. ► Crude oil price is the control variable of the model. ► There is short run bi-directional causality among oil and GDP (oil importing). ► There is short run uni-directional causality from oil to GDP (oil exporting). ► There is a long run bi-directional causality among oil and GDP in both regions.
This paper analyses the impact of several factors on the use of renewable energy sources in a set of European Union countries, by applying a quantile regression approach. We find that different ...factors are effective for different levels of renewable energy commitment and the magnitudes of some effects evolve in accordance with the level of renewable energy sources used. Consequently, some policies that do not take into account the different stages could carry different effects. The results suggest that the lobbying effect of the established industries hampers the development of renewable sources, and that this effect is greater for lower initial level of renewable energy use. The results reveal that environmental concerns have not yet achieved enough pressure to stimulate major developments on renewables. We include two new drivers, geographic area and European Union Directive 2001/77/EC. That Directive was effective in signaling the commitment to renewables, namely for countries with lower renewables use.
The present study examines the effect of both the pressure and peak temperature on the potential stability of the biochar produced from the slow pyrolysis of two-phase olive mill waste. On the basis ...of the available studies in the literature, the following properties were taken as rough indicators of the potential stability of biochars in soils: the fixed-carbon yield, the fraction of aromatic C, and the molar H:C and O:C ratios. Pyrolysis experiments were performed in a laboratory-scale fixed-bed device and planned following a central composite design. The product gas yield and composition values at the outlet of the secondary cracking reactor (a fixed-bed of activated alumina particles at 700 °C) were also analyzed as a function of pressure and peak temperature. The results from the statistical analyses indicate that both the analyzed factors have a strong influence on the distribution of the pyrolysis products, as well as on the properties of the produced biochar. The most potentially stable biochars were obtained at the highest values of pressure and peak temperature (1.1 MPa and 600 °C). A positive effect of the pressure on the pyrolysis gas yield (at the expense of the total liquid fraction) was also observed.
This work aims to improve the outstanding thermal and mechanical properties of commercialized wholly aromatic polyamide fibers (i.e., aramids), by crosslinking the materials. The introduction of a ...reactive azide group into the polymer structure leads to functional aramids. Crosslinking processes can be easily performed using an inexpensive thermal treatment after fiber spinning with current spin production facilities.
This work describes the strategy of crosslinking aromatic polyamides to increase the outstanding thermal and mechanical performances of these materials. The introduction of a reactive azide group into the polymer structure leads to a 3D network after transformation and upon heating. An important fact is that cross‐linking can be easily achieved with current aramid fiber production facilities.
The use of mixed inoculation of non-Saccharomyces yeasts and S. cerevisiae in wine fermentations is of increasing interest for quality enhancement and improved complexity of wines. The effect of ...sequential inoculation of Wickerhamomyces anomalus (formerly Hansenula anomala) with interesting enological properties in terms of secondary metabolite production and a commercial S. cerevisiae strain in fermentation of non-sterilized red musts from Mazuela variety has been examined. The wines elaborated by sequential inoculation presented higher levels of acetates and ethyl esters, compounds that supply a fruity note, higher levels of lineal alcohols, which are responsible for herbaceous notes and lower concentrations of organic acids, that contribute to increase the aromatic quality, than wines produced by a S. cerevisiae monoculture. Both types of wines were comparable in levels of volatile acidity, glycerol, lactic acid and succinic acid produced. Sensory analysis showed that red wines obtained by mixed fermentations were preferred by 71.5 % of the tasters and were particularly appreciated for its floral and/or fruity notes.
Mutations in the adaptor protein PSTPIP1 cause a spectrum of autoinflammatory diseases, including PAPA and PAMI; however, the mechanism underlying these diseases remains unknown. Most of these ...mutations lie in PSTPIP1 F-BAR domain, which binds to LYP, a protein tyrosine phosphatase associated with arthritis and lupus. To shed light on the mechanism by which these mutations generate autoinflammatory disorders, we solved the structure of the F-BAR domain of PSTPIP1 alone and bound to the C-terminal homology segment of LYP, revealing a novel mechanism of recognition of Pro-rich motifs by proteins in which a single LYP molecule binds to the PSTPIP1 F-BAR dimer. The residues R228, D246, E250, and E257 of PSTPIP1 that are mutated in immunological diseases directly interact with LYP. These findings link the disruption of the PSTPIP1/LYP interaction to these diseases, and support a critical role for LYP phosphatase in their pathogenesis.
The potential of using a synthetic cardosin-based rennet in cheese manufacturing was recently demonstrated with the development and optimization of production of a recombinant form of cardosin B in
...Kluyveromyces lactis
. With the goal of providing a more detailed characterization of this rennet, we herein evaluate the impact of the plant-specific insert (PSI) on cardosin B secretion in this yeast, and provide a thorough analysis of the specificity requirements as well as the biochemical and structural properties of the isolated recombinant protease. We demonstrate that the PSI domain can be substituted by different linker sequences without substantially affecting protein secretion and milk clotting activity. However, the presence of small portions of the PSI results in dramatic reductions of secretion yields in this heterologous system. Kinetic characterization and specificity profiling results clearly suggest that synthetic cardosin B displays lower catalytic efficiency and is more sequence selective than native cardosin B. Elucidation of the structure of synthetic cardosin B confirms the canonical fold of an aspartic protease with the presence of two high mannose-type,
N
-linked glycan structures; however, there are some differences in the conformation of the flap region when compared to cardosin A. These subtle variations in catalytic properties and the more stringent substrate specificity of synthetic cardosin B help to explain the observed suitability of this rennet for cheese production.
This study examines the Granger causality among crude oil consumption, crude oil price, dollar exchange rate and economic growth in twenty seven OECD (organisation for economic cooperation and ...development) countries over the period 1976–2009 within a panel multivariate framework. Panel cointegration tests showed the existence of long-run relationships among crude oil consumption, crude oil price and GDP (gross domestic product); and panel Granger causality test results provided empirical evidence of causality relationships running from crude oil price to crude oil consumption and also to GDP; and a bidirectional causality relationship among crude oil consumption and GDP, both in the short and long runs (feedback hypothesis). These results mean that crude oil conservation policies affect OECD economic growth in the short and long runs, and therefore, policymakers should consider that increasing crude oil price or reducing crude oil consumption adversely impacts on the economic growth rate of the OECD countries.
► We examine the Granger causality among oil, and economic growth in OECD countries. ► We use panel cointegration and panel Granger causality in a multivariate framework. ► There is bidirectional causality among economic growth and oil in the short run. ► There is bidirectional causality among economic growth and oil in the long run. ► Reduction of oil consumption leads to the reduction of economic growth in OECD.
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