Revisiting the weighting function for lightness in the CIEDE2000 colour-difference formula

We have used 13 experimental datasets (7420 colour pairs) to study the performance of the weighting function for lightness proposed by the CIEDE2000 colour-difference formula, because it has been suggested that this function can be improved by using the weighting function for lightness S_L = 1 adopted by the CIE94 colour-difference formula. Using the standardised residual sum of squares (STRESS) index, it was found that: (i) replacing the S_L in CIEDE2000 with S_L = 1 improved the results for 7/13 datasets considered, but the improvement was statistically significant only for 1/13 datasets; (ii) a Whittle-type lightness-difference formula can be used to replace the term ∆L*/S_L in CIEDE2000, which led to a new colour-difference formula with no statistically significant difference with respect to CIEDE2000 for any of the 13 experimental datasets. A modification of the CIEDE2000 formula using a Whittle-type lightness formula is proposed.     

A versatile synthesis method of dendrites-free segmented nanowires with a precise size control

ABSTRACT: We report an innovative strategy to obtain cylindrical nanowires combining well established and low-cost bottom-up methods such as template-assisted nanowires synthesis and electrodeposition process. This approach allows the growth of single-layer or multi-segmented nanowires with precise control over their length (from few nanometers to several micrometers). The employed techniques give rise to branched pores at the bottom of the templates and consequently dendrites at the end of the nanowires. With our method, these undesired features are easily removed from the nanowires by a selective chemical etching. This is crucial for magnetic characterizations where such non-homogeneous branches may introduce undesired features into the final magnetic response. The obtained structures show extremely narrow distributions in diameter and length, improved robustness and high-yield, making this versatile approach strongly compatible with large scale production at an industrial level. Finally, we show the possibility to tune accurately the size of the nanostructures and consequently provide an easy control over the magnetic properties of these nanostructures.     

STD NMR study of the interactions between antibody 2G12 and synthetic oligomannosides that mimic selected branches of gp120 glycans

The human immunodeficiency virus type-1 (HIV-1) is able to shield immunogenic peptide epitopes on its envelope spike (a trimer of two glycoproteins, gp120 and gp41) by presenting numerous host-derived N-linked glycans. Nevertheless, broadly neutralizing antibodies against gp120 and gp41 have been isolated from HIV-1-infected patients and provide protection against viral challenge in animal models. Among these, the monoclonal antibody 2G12 binds to clusters of high-mannose-type glycans that are present on the surface of gp120. These types of glycans have thus been envisaged as target structures for the development of synthetic agents capable of eliciting 2G12-like antibodies. High-resolution structural studies of 2G12 and chemically defined glycan-type ligands, including crystallographic data, have been performed to gain an insight into this interaction. Further studies are still required to design a carbohydrate-based vaccine for HIV. Our previous NMR studies highlighted different recognition modes of two branched synthetic oligosaccharides, a penta- and a heptamannoside, by 2G12 in solution. In order to clarify the underlying structural reasons for such different behaviors, we have herein "dissected" the branches into the linear tri- and tetra- oligomannosides by chemical synthesis and studied their interactions with 2G12 in solution by saturation transfer difference (STD) NMR spectroscopy. The results confirm the distinct preferences of 2G12 for the studied branches and afford explanations for the observed differences. This study provides important structural information for further ligand optimizations. Possible effects of structural modifications on the solvent-exposed end of the ligands are also discussed.     

Supercritical Fluid Extraction of Eucalyptus globulus Bark-A Promising Approach for Triterpenoid Production

Eucalyptus bark contains significant amounts of triterpenoids with demonstrated bioactivity, namely triterpenic acids and their acetyl derivatives (ursolic, betulinic, oleanolic, betulonic, 3-acetylursolic, and 3-acetyloleanolic acids). In this work, the supercritical fluid extraction (SFE) of Eucalyptus globulus deciduous bark was carried out with pure and modified carbon dioxide to recover this fraction, and the results were compared with those obtained by Soxhlet extraction with dichloromethane. The effects of pressure (100-200 bar), co-solvent (ethanol) content (0, 5 and 8% wt), and multistep operation were studied in order to evaluate the applicability of SFE for their selective and efficient production. The individual extraction curves of the main families of compounds were measured, and the extracts analyzed by GC-MS. Results pointed out the influence of pressure and the important role played by the co-solvent. Ethanol can be used with advantage, since its effect is more important than increasing pressure by several tens of bar. At 160 bar and 40 °C, the introduction of 8% (wt) of ethanol greatly improves the yield of triterpenoids more than threefold.     

Effects of particulate matter on inflammatory markers in the general adult population

Background

Particulate air pollution is associated with increased risk of cardiovascular disease and stroke. Although the precise mechanisms underlying this association are still unclear, the induction of systemic inflammation following particle inhalation represents a plausible mechanistic pathway.

Methods

We used baseline data from the CoLaus Study including 6183 adult participants residing in Lausanne, Switzerland. We analyzed the association of short-term exposure to PM₁₀ (on the day of examination visit) with continuous circulating serum levels of high-sensitive C-reactive protein (hs-CRP), interleukin 1-beta (IL-1??), interleukin 6 (IL-6), and tumor-necrosis-factor alpha (TNF-??) by robust linear regressions, controlling for potential confounding factors and assessing effect modification.

Results

In adjusted analyses, for every 10???g/m³ elevation in PM₁₀, IL-1? increased by 0.034 (95?% confidence interval, 0.007-0.060) pg/mL, IL-6 by 0.036 (0.015-0.057) pg/mL, and TNF-?? by 0.024 (0.013-0.035) pg/mL, whereas no significant association was found with hs-CRP levels.

Conclusions

Short-term exposure to PM₁₀ was positively associated with higher levels of circulating IL-1?, IL-6 and TNF-?? in the adult general population. This positive association suggests a link between air pollution and cardiovascular risk, although further studies are needed to clarify the mechanistic pathway linking PM₁₀ to cardiovascular risk.     

Effect of the drying process on the compressive strength and cell proliferation of hydroxyapatite‐derived scaffolds

The compressive strength and MC3T3 cell proliferation response of robocast hydroxyapatite‐derived scaffolds was evaluated for samples fabricated by conventional and freeze‐drying methods followed by sintering at 1100 or 1300°C. Both the sintering temperature and, especially, the drying method affected significantly the size and morphology of the residual microporosity within the robocast scaffold's struts. The freeze‐drying method generated a persistent large (1‐10 μm) microporosity of dendritic morphology that was found to improve the biological response of hydroxyapatite‐derived scaffolds. Conversely, conventional drying enhances the compressive strength of the structures. Strength was also increased at the higher sintering temperature, although at the expense of a poorer cell proliferation behavior. The results of this study suggest that the use of a freeze drying process after printing by robocasting provides a very appropriate method for enhancing the biological performance and reliability of bioceramic robocast scaffolds without severely reducing their compressive strength. And, thus, shows promise as an effective method to optimize the performance of robocast scaffolds for bone tissue regeneration.     

Effects of low-temperature aging on AISI 444 steel

The consequences of aging at 400 and 475 °C on the mechanical properties, corrosion resistance, and magnetic properties of the ferritic stainless steel (SS) AISI 444 were investigated. Age hardening was measured as a function of aging time at both temperatures and was found to be more intense at 475 °C. The localized corrosion susceptibility increased, while the impact toughness decreased with aging time. These two effects were also more important at 475 °C. Unlike duplex SSs, AISI 444 did not present any variation in coercive force or Curie temperature with aging time. The effects on the Mössbauer spectra were also determined and analyzed.     

Chemical composition and fatty acid profile of rhea (Rhea americana) meat

The purpose of this work was to determine the proximate composition and fatty acid profiles of the Gastrocnemius pars interna intramuscular fat (IMF) of rhea (Rhea americana) thighs. The birds were bred in captivity, fed with balanced feed (Nutriavestruz Crescimento - Purina) and kept in a pen with grass ad lib. The birds of both sexes used in the research weighed 23 kg on average and were aged about twelve (12) months old. They were subjected to hydric diet (12 h) before slaughtering by electric shock. The rhea meat showed an average moisture, protein, ash and total lipid contents of 74.1%, 22.8%, 1.5% and 1.6%, respectively. It was noticed the predominance of monounsaturated fatty acids (MUFA) in intramuscular fat (IMF), 42.3% and a high percentage of polyunsaturated fatty acids (PUFA), 29.7%. The fatty acids found in higher proportion in rhea IMF were: 18:2n-6 (24.33%), 18: ln-9 (19.25%), 16:0 (13.70%), 22: ln9 (11.40%), 18:0 (10.66%), 15: ln-10 (8.62%), 24: ln-9 (2.90%) and 20:4n-6 (1.72%). The PUFA/SFA and n-6/n-3 ratios were 1.06 and 31.30, respectively. The consumption of rhea meat is a healthy alternative to red meat as it points to a lower susceptibility to cardiovascular diseases caused by the high consumption of fat comparatively to the consumption of meat from most domesticated animals.     

Electrochemical corrosion parameters of as-cast Al-Fe alloys in a NaCl solution

The aim of this study is to evaluate the general electrochemical corrosion resistance of Al-Fe alloys in the range of hypoeutectic compositions, Al-0.5 wt.% Fe and Al-1.5 wt.% Fe alloy. EIS plots, potentiodynamic polarization curves and an equivalent circuit analysis were used to evaluate the electrochemical parameters in a 0.5 M NaCl solution at 25 °C. It is shown that for an Al-0.5 wt.% Fe alloy, coarse cells tend to improve the corrosion resistance mainly due to the reduction in cellular boundaries and for an Al-1.5 wt.% Fe alloy, an opposite trend has been detected.