6,066 research outputs found
Chemo-enzymatic saccharification strategy of microalgae chlorella sorokiniana
Biofuel production using microalgae attracted much attention because it can be cultured using CO2 and sunlight. With high carbohydrate content, microalgae have the potential to be used as a fermentation feedstock for bioethanol production. In present work, chemo-enzymatic saccharification of Chlorella sorokiniana microalgae were investigated. Chemical hydrolysis of the biomass followed by enzymatic hydrolysis and was also evaluated the effect of combining the two enzymes and the sequential addition. The effect of α-amylase concentrations was analyzed in ranged between 50 and 8000 U/g of biomass and for amyloglucosidase between 90 and 600 U/g of biomass. The higher concentrations showed the highest conversion of reducing sugars. The α-amylase concentration 8000 U/g of biomass presented a conversion of 43.06â±â2.92% (w/w), while amyloglucosidase with 600 U/g of biomass obtained 76.57â±â6.42% (w/w). The combination of two enzymes simultaneously was more efficient than the sequential addition for low enzyme concentrations (α-amylase 50 U/g and amyloglucosidase 90 U/g) with a total reducing sugar of 22.78â±â3.06 and 16.92â±â2.06% (w/w), respectively. On the other hand, using the higher enzymes concentrations, no difference was observed between the two addition strategies, 58.9â±â3.55 and 57.05â±â2.33% (w/w) for the sequential and simultaneous, respectively. Both strategies didnât present advantage, since the amyloglucosidase enzyme alone produced slightly higher results. Even thought, the obtained results showed successfully performed saccharification of microalgal biomass and clearly point to microalgae use for saccharification and subsequent bioethanol production.Part of this work has been supported by European governments (INTERREG VA-POCTEP- 2014-2020; 0055_ALGARED_PLUS_5_E) and the Portuguese Science Foundation (FCT) through the grant UID/MAR/00350/2013 to the CIMA of the University of Algarve.info:eu-repo/semantics/publishedVersio
Backlash and State Strategies in International Investment Law
This book provides an important corrective to existing theories of international law by focusing on how states respond to increased legalisation and rely on legal expertise to manoeuvre within and against international law
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Rational Design of Pore Size and Functionality in a Series of Isoreticular Zwitterionic Metal-Organic Frameworks
The isoreticular expansion and functionalization of charged-polarized porosity has been systematically explored by the rational design of 11 isostructural zwitterionic metal-organic frameworks (ZW-MOFs). This extended series of general structural composition {[M3F(L1)3(L2)1.5]·guests}n was prepared by employing the solvothermal reaction of Co and Ni tetrafluoroborates with a binary ligand system composed of zwitterionic pyridinium derivatives and traditional functionalized ditopic carboxylate auxiliary ligands (HL1·Cl = 1-(4-carboxyphenyl)-4,4âČ-bipyridinium chloride, Hcpb·Cl; or 1-(4-carboxyphenyl-3-hydroxyphenyl)-4,4âČ-bipyridinium chloride, Hchpb·Cl; and H2L2 = benzene-1,4-dicarboxylic acid, H2bdc; 2-aminobenzene-1,4-dicarboxylic acid, H2abdc; 2,5-dihydroxy-1,4-benzenedicarboxylic acid, H2dhbdc; biphenyl-4,4âČ-dicarboxylic acid, H2bpdc; or stilbene-4,4âČ-dicarboxylic acid, H2sdc). Single-crystal structure analyses revealed cubic crystal symmetry (I-43m, a = 31-36 Ă
) with a 3D pore system of significant void space (73-81%). The pore system features three types of pores being systematically tunable in size ranging from 17.4 to 18.8 Ă
(pore I), 8.2 to 12.8 Ă
(pore II), and 4.8 to 10.4 Ă
(pore III) by the choice of auxiliary ligands. All members of this series have noninterpenetrating structures and exhibit robust architectures, as evidenced by their permanent porosity and high thermal stability (up to 300 °C). The structural integrity and specific surface areas could be systematically optimized using supercritical CO2 exchange methods for framework activation resulting in BET surface areas ranging from 1250 to 2250 m2/g. Most interestingly, as a structural landmark, we found the pore surfaces lined with charge gradients employed by the pyridinium ligands. This key feature results in significant adsorption of carbon dioxide and methane which is attributed to polarization effects. With this contribution we pioneer the reticulation of pyridinium building blocks into extended zwitterionic networks in which specific properties can be targeted
Etude de l'effet de l'amodiaquine sur les globules rouges infectés par le paludisme dans les images multispectrales
Nous avons montrĂ© que lâamodiaquine se fixe prĂ©fĂ©rentiellement dans les globules rouges infectĂ©s et nous avons Ă©galement Ă©tĂ© capable de retrouver les concentrations du mĂ©dicament dans les cellules, Ă partir dâimages multispectrales. Une scĂšne d'images multispectrales de frottis sanguins non marquĂ©s est obtenue Ă partir dâune culture de plasmodium falciparum, Ă laquelle nous avons ajoutĂ© diffĂ©rentes doses dâamodiaquine (AQ) ; Les images sont obtenues Ă partir d'enregistrement de treize capteurs spectraux couplĂ©s Ă un microscope multimodal et multispectral. Ces images sont ensuite utilisĂ©es pour Ă©tudier lâinteraction du mĂ©dicament avec les globules rouges en fonction des concentrations, en ayant recours Ă des techniques dâanalyse multivariĂ©e telles que la classification hiĂ©rarchique, la mĂ©thode des k-moyennes et lâanalyse en composante principale. Les rĂ©sultats obtenus nous montrent que lâimagerie multispectrale est un atout majeur pour le diagnostic mĂ©dical et peut donc constituer une technique de routine pour lâĂ©tude de nouvelles molĂ©cules antipaludiques, notamment issues de la pharmacopĂ©e africaine.Mots-clĂ©s: imagerie multispectrale, classification hiĂ©rarchique, analyse en composante principale, k-moyennes.Study of the Effect of Amodiaquine on Red Blood Cells Infected by Malaria in Multispectral ImagesWe have demonstrated that amodiaquine binds preferentially in the infected red blood cells and we have also been able to retrieve the drug concentrations in the cells. A scene of multispectral images of free labelled blood smears have been obtained from plasmodium falciparum culture to which we have added different quantities of amodiaquine; the images have been recorded from thirteen spectral sensors coupled with a multimodal and multispectral microscope. These images have been used to study the interaction of the drug with the red blood cells as function of drug concentration by the use of multivariate statistical analysis techniques such as hierarchical classification, k-means method and principal component analysis techniques. The results show that the multispectral imagery is a key technique in medical technologies and can therefore be used as routine method for antimalarial drug design, especially in African traditional pharmacopeia study.Keywords: multispectral imagery; hierarchical classification; principal component analysis; k-means
Variation in bulk-leaf <sup>13</sup>C discrimination, leaf traits and water-use efficiencyâtrait relationships along a continental-scale climate gradient in Australia
© 2017 John Wiley & Sons Ltd Large spatial and temporal gradients in rainfall and temperature occur across Australia. This heterogeneity drives ecological differentiation in vegetation structure and ecophysiology. We examined multiple leaf-scale traits, including foliar 13C isotope discrimination (Î13C), rates of photosynthesis and foliar N concentration and their relationships with multiple climate variables. Fifty-five species across 27 families were examined across eight sites spanning contrasting biomes. Key questions addressed include: (i) Does Î13C and intrinsic water-use efficiency (WUEi) vary with climate at a continental scale? (ii) What are the seasonal and spatial patterns in Î13C/WUEi across biomes and species? (iii) To what extent does Î13C reflect variation in leaf structural, functional and nutrient traits across climate gradients? and (iv) Does the relative importance of assimilation and stomatal conductance in driving variation in Î13C differ across seasons? We found that MAP, temperature seasonality, isothermality and annual temperature range exerted independent effects on foliar Î13C/WUEi. Temperature-related variables exerted larger effects than rainfall-related variables. The relative importance of photosynthesis and stomatal conductance (gs) in determining Î13C differed across seasons: Î13C was more strongly regulated by gs during the dry-season and by photosynthetic capacity during the wet-season. Î13C was most strongly correlated, inversely, with leaf mass area ratio among all leaf attributes considered. Leaf Nmass was significantly and positively correlated with MAP during dry- and wet-seasons and with moisture index (MI) during the wet-season but was not correlated with Î13C. Leaf Pmass showed significant positive relationship with MAP and Î13C only during the dry-season. For all leaf nutrient-related traits, the relationships obtained for Î13C with MAP or MI indicated that Î13C at the species level reliably reflects the water status at the site level. Temperature and water availability, not foliar nutrient content, are the principal factors influencing Î13C across Australia
V902 Monocerotis: a likely disc-accreting intermediate polar
Aims: We aim to confirm whether the eclipsing cataclysmic variable V902 Mon
is an Intermediate Polar, to characterise its X-ray spectrum and flux, and to
refine its orbital ephemeris and spin period. Methods: We performed
spectrographic observations of V902 Mon in 2016 with the 2.2m Calar Alto
telescope, and X-ray photometry and spectroscopy with XMM-Newton in October
2017. This data was supplemented by several years of AAVSO visual photometry.
Results: We have confirmed V902 Mon as an IP based on detecting the spin
period, with a value of 2,208s, at multiple epochs. Spectroscopy of the donor
star and Gaia parallax yield a distance of 3.5+1.3-0.9, kpc, suggesting an
X-ray luminosity one or two orders of magnitude lower than the 10^33 erg/s
typical of previously known IPs. The X-ray to optical flux ratio is also very
low. The inclination of the system is more than 79deg, with a most likely value
of around 82deg. We have refined the eclipse ephemeris, stable over 14,000
cycles. The Halpha line is present throughout the orbital cycle and is clearly
present during eclipse, suggesting an origin distant from the white dwarf, and
shows radial velocity variations at the orbital period. The amplitude and
overall recessional velocity seem inconsistent with an origin in the disc. The
\emph{XMM-Newton} observation reveals a partially absorbed plasma model typical
of magnetic CVs, with a fluorescent iron line at 6.4keV showing a large
equivalent width of 1.4keV. Conclusions: V902 Mon is an IP, and probably a
member of the hypothesized X-ray underluminous class of IPs. It is likely to be
a disc accretor, though the radial velocity behaviour of the Halpha line
remains puzzling. The large equivalent width of the fluorescent iron line, the
small FX/Fopt ratio, and the only marginal detection of X-ray eclipses suggests
that the X-ray emission arises from scattering.Comment: 10 pages, 12 figure
Growth and development of date palm (Phoenix dactylifera L.) seedlings under drought and salinity stresses
The present investigation has been performed to evaluate date palm (Phoenix dactylifera L.) tolerance to osmotic stress induced by polyethylene glycol (PEG) or NaCl during the early stages of plant development. Two varieties Nakhla hamra (NHH) and Tijib widely cultivated in Mauritania were tested.NHH showed increasing of epicotyl length, primary root length, secondary root number and proline content when water deficit was induced by PEG. In contrast, on the basis of the same developmental and biochemical characters, the Tijib cultivar was more tolerant in salinity stress. This difference of cultivars’ behavior according the growth conditions is discussed
20 K superconductivity in heavily electron doped surface layer of FeSe bulk crystal
A superconducting transition temperature Tc as high as 100 K was recently
discovered in 1 monolayer (1ML) FeSe grown on SrTiO3 (STO). The discovery
immediately ignited efforts to identify the mechanism for the dramatically
enhanced Tc from its bulk value of 7 K. Currently, there are two main views on
the origin of the enhanced Tc; in the first view, the enhancement comes from an
interfacial effect while in the other it is from excess electrons with strong
correlation strength. The issue is controversial and there are evidences that
support each view. Finding the origin of the Tc enhancement could be the key to
achieving even higher Tc and to identifying the microscopic mechanism for the
superconductivity in iron-based materials. Here, we report the observation of
20 K superconductivity in the electron doped surface layer of FeSe. The
electronic state of the surface layer possesses all the key spectroscopic
aspects of the 1ML FeSe on STO. Without any interface effect, the surface layer
state is found to have a moderate Tc of 20 K with a smaller gap opening of 4
meV. Our results clearly show that excess electrons with strong correlation
strength alone cannot induce the maximum Tc, which in turn strongly suggests
need for an interfacial effect to reach the enhanced Tc found in 1ML FeSe/STO.Comment: 5 pages, 4 figure
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