Design of eco-friendly fabric softeners: structure, rheology and interaction with cellulose nanocrystals

Concentrated fabric softeners are water-based formulations containing around 10 - 15 wt. % of double tailed esterquat surfactants primarily synthesized from palm oil. In recent patents, it was shown that a significant part of the surfactant contained in today formulations can be reduced by circa 50 % and replaced by natural guar polymers without detrimental effects on the deposition and softening performances. We presently study the structure and rheology of these softener formulations and identify the mechanisms at the origin of these effects. The polymer additives used are guar gum polysaccharides, one cationic and one modified through addition of hydroxypropyl groups. Formulations with and without guar polymers are investigated using optical and cryo-transmission electron microscopy, small-angle light and Xray scattering and finally rheology. Similar techniques are applied to study the phase behavior of softener and cellulose nanocrystals considered here as a model for cotton. The esterquat surfactants are shown to assemble into micron-sized vesicles in the dilute and concentrated regimes. In the former, guar addition in small amounts does not impair the vesicular structure and stability. In the concentrated regime, cationic guars induce a local crowding associated to depletion interactions and leads to the formation of a local lamellar order. In rheology, adjusting the polymer concentration at one tenth that of the surfactant is sufficient to offset the decrease of the elastic property associated with the surfactant reduction. In conclusion, we have shown that through an appropriate choice of natural additives it is possible to lower the concentration of surfactants in fabric conditioners by about half, a result that could represent a significant breakthrough in current home care formulations.Comment: 10 pages 8 figure

The price of informality : how informal finance schemes defaulted in China, 1989–2015.

The default of a large number of informal finance schemes in China has caused enormous financial losses, and therefore has potential social and political significance. Analysing 354 defaulted schemes from 1989 to 2015, this study defines how they differ from other types of informal finance. It also produces an ideal-type representation of the default process and concludes that the default results from greed, increasing financial pressure at the individual level and private enterprises’ restricted access to state bank loans at the institutional level. China’s financial system should be more flexible in order to prevent further financial losses through informal financial relations

Straightforward determination of the degree of N-acetylation of chitosan by means of first-derivative UV spectrophotometry

First-derivative UV spectrophotometry is shown to be a reliable method for the determination of the degree of N-acetylation of chitosan samples. A mathematical expression is derived that allows to determine the DA directly from the mass concentration of a chitosan solution and the first derivative of its UV spectrum at 202 nm, thus eliminating the need for empiric correction curves for highly deacetylated samples. A procedure is proposed for the accurate mass determination of the hygroscopic chitosan. The proposed approach facilitates the routine determination of the DA, especially when using potent multiwell microplate readers, which allow hundreds of samples to be measured in just a few minutes

Intensification of yeast production with microbubbles

Yeast requires and consumes a high amount of oxygen rapidly during growth. Maintaining yeast cultures under sufficient aeration, however, is a significant challenge in yeast propagation. Due to their high surface area, microbubbles are more efficient in mass transfer than coarse bubbles. The performance of an airlift loop bioreactor equipped with a fluidic oscillator generated microbubbles in yeast propagation is presented here. The approach is compared with a conventional bubble generation method that produces coarse bubbles. Dosing with microbubbles transferred more oxygen to the cultures, achieving non-zero dissolved O2 levels and consequently, eliminating the starvation state of yeast in contrast to coarse bubble sparging. The average cell growth yield obtained under microbubble sparging reached 0.31 mg/h (±0.02) while 0.22 mg/h (±0.01) was recorded for cells grown with coarse bubbles during the log phase. The percent difference in average growth yield after 6 hours was 18%. Additionally, the use of microbubbles in yeast harvest from growth medium proved effective, yielding >99% cell recovery. The result of this study is crucial for the biofuel industry but also, the food, nutraceutical and pharmaceutical industry for which end product purity is premium

Structural Variations in Hybrid All-Nanoparticle Gibbsite Nanoplatelet/Cellulose Nanocrystal Multilayered Films

Cellulose nanocrystals (CNCs) are promising bio-sourced building blocks for the production of high performance materials. In the last ten years, CNCs have been used in conjunction with polymers for the design of multilayered thin films via the layer-by-layer assembly technique. Herein, polymer chains have been replaced with positively charged inorganic gibbsite nanoplatelets (GN) to form hybrid “nanoparticle-only” composite films. A combination of atomic force microscopy and neutron reflectivity experiments was exploited to investigate the growth and structure of the films. Data show that the growth and density of GN/CNC films can be tuned over a wide range during preparation by varying the ionic strength in the CNC suspension and the film drying protocol. Specifically, thin and dense multilayered films or very thick, more porous mixed slabs, as well as intermediate internal structures could be obtained in a predictable manner. The influence of key physicochemical parameters on the multilayer film build up was elucidated and the film architecture was linked to the dominating interaction forces between components. The degree of structural control over these hybrid nanoparticle-only films is much higher than that reported for CNC/polymer films, which offers new properties and potential applications as separation membranes or flame retardant coatings

Widespread dynamic and pleiotropic expression of the melanocortin-1-receptor (MC1R) system is conserved across chick, mouse and human embryonic development

Background MC1R, a G‐protein coupled receptor with high affinity for alpha‐melanocyte stimulating hormone (αMSH), modulates pigment production in melanocytes from many species and is associated with human melanoma risk. MC1R mutations affecting human skin and hair color also have pleiotropic effects on the immune response and analgesia. Variants affecting human pigmentation in utero alter the congenital phenotype of both oculocutaneous albinism and congenital melanocytic naevi, and have a possible effect on birthweight. Methods and Results By in situ hybridization, RT‐PCR and immunohistochemistry, we show that MC1R is widely expressed during human, chick and mouse embryonic and fetal stages in many somatic tissues, particularly in the musculoskeletal and nervous systems, and conserved across evolution in these three amniotes. Its dynamic pattern differs from that of TUBB3, a gene overlapping the same locus in humans and encoding class III β‐tubulin. The αMSH peptide and the transcript for its precursor, pro‐opiomelanocortin (POMC), are similarly present in numerous extra‐cutaneous tissues. MC1R genotyping of variants p.(V60M) and p.(R151C) was undertaken for 867 healthy children from the Avon Longitudinal Study of Parent and Children (ALSPAC) cohort, and birthweight modeled using multiple logistic regression analysis. A significant positive association initially found between R151C and birth weight, independent of known birth weight modifiers, was not reproduced when combined with data from an independent genome‐wide association study of 6,459 additional members of the same cohort. Conclusions These data clearly show a new and hitherto unsuspected role for MC1R in noncutaneous solid tissues before birth

Current state and challenges for dynamic metabolic modeling

While the stoichiometry of metabolism is probably the best studied cellular level, the dynamics in metabolism can still not be well described, predicted and, thus, engineered. Unknowns in the metabolic flux behavior arise from kinetic interactions, especially allosteric control mechanisms. While the stoichiometry of enzymes is preserved in vitro, their activity and kinetic behavior differs from the in vivo situation. Next to this challenge, it is infeasible to test the interaction of each enzyme with each intracellular metabolite in vitro exhaustively. As a consequence, the whole interacting metabolome has to be studied in vivo to identify the relevant enzymes properties. In this review we discuss current approaches for in vivo perturbation experiments, that is, stimulus response experiments using different setups and quantitative analytical approaches, including dynamic carbon tracing. Next to reliable and informative data, advanced modeling approaches and computational tools are required to identify kinetic mechanisms and their parameters.The authors EV, AT, KN, IR, MO, DM and AW are part of the ERA-IB funded consortium DYNAMICS (ERA-IB-14-081, NWO 053.80.724)

A new waterborne chitosan-based polyurethane hydrogel as a vehicle to transplant bone marrow mesenchymal cells improved wound healing of ulcers in a diabetic rat model

[EN] Foot ulcers, a common complication of diabetes, can cause physical incapacity and are derived from several factors, including poor wound healing. New therapeutic strategies are needed to minimize this complication for the sake of patients' health. We therefore developed a new chitosan- polyurethane hydrogel membrane (HPUC) and the WA results confirmed that HPUC present low cytotoxicity and improved wound healing when used with mononuclear bone marrow fraction cells in the diabetic rat model. The biodegradable hydrogels were produced in block copolymer networks with a combination of chitosan blocks and biodegradable polyurethane. The membranes were characterized by FTIR, C-13-NMR and thermogravimetry. Swelling and hydrolytic degradation were also evaluated. The non-solubility of the membranes in good solvents and the chemical characterization confirmed that the network structure was formed between the PU and the chitosan through urea/urethane bonds. The findings confirm that the HPUC have interesting properties that make them suitable for wound healing applications.This work was funded by: Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -doctoral fellowships to Viezzer, C (CAPES/PDSE-BEX: 1408/11-9) and the Spanish Ministry of Economy and Competitiveness (MINECO) through the MAT2016-76039-C4-1-R Project, including FEDER financial support. CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.Viezzer, C.; Mazzuca, R.; Machado, DC.; Forte, MMDC.; Gómez Ribelles, JL. (2020). A new waterborne chitosan-based polyurethane hydrogel as a vehicle to transplant bone marrow mesenchymal cells improved wound healing of ulcers in a diabetic rat model. 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Aphanomyces euteiches cell wall fractions containing novel glucan-chitosaccharides induce defense genes and nuclear calcium oscillations in the plant host Medicago truncatula

N-acetylglucosamine-based saccharides (chitosaccharides) are components of microbial cell walls and act as molecular signals during host-microbe interactions. In the legume plant Medicago truncatula, the perception of lipochitooligosaccharide signals produced by symbiotic rhizobia and arbuscular mycorrhizal fungi involves the Nod Factor Perception (NFP) lysin motif receptor-like protein and leads to the activation of the so-called common symbiotic pathway. In rice and Arabidopsis, lysin motif receptors are involved in the perception of chitooligosaccharides released by pathogenic fungi, resulting in the activation of plant immunity. Here we report the structural characterization of atypical chitosaccharides from the oomycete pathogen Aphanomyces euteiches, and their biological activity on the host Medicago truncatula. Using a combination of biochemical and biophysical approaches, we show that these chitosaccharides are linked to β-1,6-glucans, and contain a β-(1,3;1,4)-glucan backbone whose β-1,3-linked glucose units are substituted on their C-6 carbon by either glucose or N-acetylglucosamine residues. This is the first description of this type of structural motif in eukaryotic cell walls. Glucan-chitosaccharide fractions of A. euteiches induced the expression of defense marker genes in Medicago truncatula seedlings independently from the presence of a functional Nod Factor Perception protein. Furthermore, one of the glucan-chitosaccharide fractions elicited calcium oscillations in the nucleus of root cells. In contrast to the asymmetric oscillatory calcium spiking induced by symbiotic lipochitooligosaccharides, this response depends neither on the Nod Factor Perception protein nor on the common symbiotic pathway. These findings open new perspectives in oomycete cell wall biology and elicitor recognition and signaling in legumes.Amaury Nars, Claude Lafitte, Mireille Chabaud, Sophie Drouillard, Hugo Mélida, Saïda Danoun, Tinaig Le Costaouëc, Thomas Rey, Julie Benedetti, Vincent Bulone, David George Barker, Jean-Jacques Bono, Bernard Dumas, Christophe Jacquet, Laurent Heux, Judith Fliegmann, Arnaud Botti