Aggregation and phase equilibria of fluorinated ionic liquids

Grant SFRH/BD/100563/2014. IF/00190/2014 . IF/00210/2014. PTDC/EQU-EQU/29737/2017. PTDC/QEQ-FTT/3289/2014. IF/00210/2014/CP1244/CT0003. UID/QUI/50006/2019. POCI-01-0145-FEDER - 007265.In this work a specific family of ionic liquids, denominated fluorinated ionic liquids, with fluorine tags equal or longer than four carbon atoms, are fully characterized in order to understand their solubility and self-aggregation in aqueous solutions. The numerous combinations between cations and anions make these compounds a feasible option for the replacement of traditional and toxic surfactants used in the industrial and biomedical field. In this work, the increment of both hydrogenated and fluorinated side chain lengths, the influence of the cation headgroup (imidazolium and cholinium)as well as the difference between perfluorobutanesulfonate and perfluoropentanoate anions were studied. The liquid-liquid phase equilibria of fluorinated ionic liquids based on the perfluorobutanesulfonate anion with water were carried out. The self-aggregation behaviour of the different fluorinated ionic liquids in aqueous solutions was also determined using conductimetric titration, surface tension measurements and transmission electron microscopy. Several thermodynamic and surface parameters were obtained and used to discuss the aggregation process. These novel characterized fluorinated ionic liquids demonstrate an improved surface activity and aggregation behaviour, driven essentially by the increment of both hydrogenated and fluorinated chain lengths.authorsversionpublishe

Effectiveness of rotavirus vaccination in Spain

With the aim of determining rotavirus vaccine effectiveness (RVVE) in Spain, from Oct-2008/Jun-2009, 467 consecutive children below 2 years old with acute gastroenteritis (AGE) were recruited using a pediatric research network (ReGALIP-www.regalip.org) that includes primary, emergency and hospital care settings. Of 467 enrolled children, 32.3% were rotavirus positive and 35.0% had received at least one dose of any rotavirus vaccine. RRVE to prevent any episode of rotavirus AGE was 91.5% (95% CI: 83.7%-95.6%). RVVE to prevent hospitalization by rotavirus AGE was 95.6% (85.6-98.6%). No differences in RVVE were found regarding the vaccine used. Rotavirus vaccines have showed an outstanding effectiveness in Spain

Age-Related Neuronal Degeneration: Complementary Roles of Nucleotide Excision Repair and Transcription-Coupled Repair in Preventing Neuropathology

Neuronal degeneration is a hallmark of many DNA repair syndromes. Yet, how DNA damage causes neuronal degeneration and whether defects in different repair systems affect the brain differently is largely unknown. Here, we performed a systematic detailed analysis of neurodegenerative changes in mouse models deficient in nucleotide excision repair (NER) and transcription-coupled repair (TCR), two partially overlapping DNA repair systems that remove helix-distorting and transcription-blocking lesions, respectively, and that are associated with the UV-sensitive syndromes xeroderma pigmentosum (XP) and Cockayne syndrome (CS). TCR–deficient Csa−/− and Csb−/− CS mice showed activated microglia cells surrounding oligodendrocytes in regions with myelinated axons throughout the nervous system. This white matter microglia activation was not observed in NER–deficient Xpa−/− and Xpc−/− XP mice, but also occurred in XpdXPCS mice carrying a point mutation (G602D) in the Xpd gene that is associated with a combined XPCS disorder and causes a partial NER and TCR defect. The white matter abnormalities in TCR–deficient mice are compatible with focal dysmyelination in CS patients. Both TCR–deficient and NER–deficient mice showed no evidence for neuronal degeneration apart from p53 activation in sporadic (Csa−/−, Csb−/−) or highly sporadic (Xpa−/−, Xpc−/−) neurons and astrocytes. To examine to what extent overlap occurs between both repair systems, we generated TCR–deficient mice with selective inactivation of NER in postnatal neurons. These mice develop dramatic age-related cumulative neuronal loss indicating DNA damage substrate overlap and synergism between TCR and NER pathways in neurons, and they uncover the occurrence of spontaneous DNA injury that may trigger neuronal degeneration. We propose that, while Csa−/− and Csb−/− TCR–deficient mice represent powerful animal models to study the mechanisms underlying myelin abnormalities in CS, neuron-specific inactivation of NER in TCR–deficient mice represents a valuable model for the role of NER in neuronal maintenance and survival

Dynamics of Polyelectrolyte Transport through a Protein Channel as a Function of Applied Voltage

International audienceWe study the transport of dextran sulfate through a protein channel as a function of applied voltage. Below 60 mV, the chain’s entrance to the pore is hindered by an entropic barrier; above 60 mV, the strong local electric field forces the chain entrance. The effective charge of the polyelectrolyte inside the pore is reduced. We observe two types of blockades which have durations that decrease when the applied voltage increases. The shortest is a straddling time between the polyelectrolyte and the pore; the longest is the translocation time. The translocation time obeys an exponential dependence upon applied voltage

High-Pressure Biodiesel Density: Experimental Measurements, Correlation, and Cubic-Plus-Association Equation of State (CPA EoS) Modeling

Density is one of the most important biodiesel properties, because engine injection systems (pumps and injectors) must deliver an amount of fuel precisely adjusted to provide a proper combustion while minimizing greenhouse gas emissions. The pressure influence in fuel density has become particularly important with the increased use of modern common rail systems, where pressures can reach 250 MPa. Nevertheless, besides its importance, little attention has been given to high-pressure biodiesel densities. In fact, there are almost no reports in the literature about experimental high-pressure biodiesel density data. To overcome this lack of information, in this work, new experimental measurements, from 283 to 333 K and from atmospheric pressure to 45 MPa, were performed for methyl laurate, methyl myristate, and methyl oleate, for methyl biodiesels from palm, soybean, and rapeseed oils, and for three binary and one ternary mixture of these oils. Following previous works, where the cubic-plus-association equation of state (CPA EoS) was shown to be the most appropriate model to be applied to biodiesel production and purification processes, the new high-pressure experimental data reported here were also successfully predicted with the CPA EoS, with a maximum deviation of 2.5%. A discussion about the most appropriate CPA pure compound parameters for fatty acid methyl esters is also presented

Single Molecule Detection of Glycosaminoglycan Hyaluronic Acid Oligosaccharides and Depolymerization Enzyme Activity Using a Protein Nanopore

International audienceGlycosaminoglycans are biologically active anionic carbohydrates that are among the most challenging biopolymers with regards to their structural analysis and functional assessment. The potential of newly introduced biosensors using protein nanopores that have been mainly described for nucleic acids and protein analysis to date, has been here applied to this polysaccharide-based third class of bioactive biopolymer. This nanopore approach has been harnessed in this study to analyze the hyaluronic acid glycosamiglycan and its depolymerization-derived oligosaccharides. The translocation of a glycosaminoglycan is reported using aerolysin protein nanopore. Nanopore translocation of hyaluronic acid oligosaccharides was evidenced by the direct detection of translocated molecules accumulated into the arrival compartment using high-resolution mass spectrometry. Anionic oligosaccharides of various polymerization degrees were discriminated through measurement of the dwelling time and translocation frequency. This molecular sizing capability of the protein nanopore device allowed the real-time recording of the enzymatic cleavage of hyaluronic acid polysaccharide. The time-resolved detection of enzymatically produced oligosaccharides was carried out to monitor the depolymerization enzyme reaction at the single-molecule level