Use of a sol-gel hybrid coating composed by a fluoropolymer and silica for the mitigation of mineral fouling in heat exchangers

The technology of the organic/inorganic hybrid coating was employed in the preparation of a hydrophobic coating (contact angle higher than 140\ub0) for fouling mitigation on stainless steel heat transfer surfaces. A commercial triethoxysilane perfluoropolyethers was combined with a sol-gel silica network with the aim to increase the mechanical and thermal resistance of the films when exposed to aggressive liquid environments as the heat exchanging fluids. The experimentation on a shell and tube heat exchanger pilot plant confirmed the ability of the hybrid coating to prolong the crystallization fouling induction period of 200 h in respect to an uncoated heat exchanger, operating in the same conditions. Moreover, the fouling particles deposited on the coated heat transfer surfaces had only slight adhesion strength toward the coated surfaces and were easily removed by inducing higher wall shear stresses inside the tubes of the plant

Perfluoropolyethers coatings design for fouling reduction on heat transfer stainless steel surfaces

The scope of this research is to obtain a film coating on stainless steel surfaces in order to reduce the interaction between the metal surface and the precipitates, so to mitigate fouling in heat exchangers. Perfuoropolyethers were used to obtain nano-range fluorinated layers in order to make hydrophobic the stainless steel surfaces. A pilot plant with two identical heat exchangers was built to investigate the ability of the hydrophobic coating of preventing fouling. The heat exchangers, installed in parallel, operated at the same temperature and pressure conditions, i.e. laminar flow regime and inlet flow temperatures of 291\u2013293 K for cold streams and 313\u2013333 K for hot streams. We compared the heat transfer performance of the two heat exchangers. After a five months operation the decrease in the heat transferred was 56% for the coated heat exchanger and 62% for the uncoated heat exchanger. Moreover, the increase of heat transfer resistance due to scale on the uncoated heat exchanger, with respect to the coated one, was three times higher

Reply to: "Pre-retrieval reperfusion decreases cancer recurrence after rat ischemic liver graft transplantation"

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Reinforcement of perfluoropolyethers coatings by ceramic oxides sol-gels for fouling mitigation on metal surfaces

In this research we developed a coating formulation containing \u3b1,\u3c9-substituted perfluoropolyethers (PFPE) and ceramic oxides sol-gels, for fouling mitigation on solid surfaces. Micrometer coatings where obtained on metal substrates by dip-coating procedure; they showed hydrophobic behavior (CA>130\ub0) and low CA hysteresis. The coatings resistance against shear stresses and chemicals increased thanks to the high mechanical properties of the ceramic oxides, compared to a simple PFPE coating. The ability of the coatings to mitigate particulate fouling was preliminary confirmed in presence of CaSO4 in an appropriate test rig. Motivations and Objectives One potential application of hydrophobic coatings concerns fouling mitigation. It has been demonstrated that low energy surfaces are able to influence the mechanism of deposition and removal of fouling particles on heat transfer surfaces, increasing the fouling induction period of the heat exchangers [1]. This research aims to develop a hydrophobic organic-inorganic coating, combining a PFPE with a sol-gel network obtained from the hydrolysis of tetraethylorthosilicate (OTES) or Zr-n-propoxide, in order to improve the mechanical properties of the final coatings. The investigation focuses the attention on the important coatings parameters for a possible application on heat transfer surfaces, i.e., thickness, thermal resistance, surface roughness and chemical and physical resistance. Fouling mitigation ability of the coatings is assessed in particulate fouling conditions, in a specific test rig. Hydrophobic coatings were obtained by formulating in iso-propanol a commercial PFPE (Fluorolink\uaeS10) with SiO2 or ZrO2 sol-gels, at different weight proportion (80/20, 1/05 and 1/1 respectively). The coatings resistance was investigated against erosion induced by liquid environments and shear stresses induced by a water flow. Compared to a simple PFPE coating, the resistance against shear stresses and aggressive environments increased of the 90%. Fouling mitigation ability of coatings deposited on the internal surfaces of a stainless steel tube, was assessed in presence of a CaSO4 solution (4 g/L), flowed inside a coated tube (temperature=40\ub0C, flowrate= 1.5 m/s). Thanks to the hydrophobic coating, the foulants deposition is 95% lower in respect to an uncoated surface

Neurometabolic changes in a rat pup model of type C hepatic encephalopathy depend on age at liver disease onset.

Chronic liver disease (CLD) is a serious condition where various toxins present in the blood affect the brain leading to type C hepatic encephalopathy (HE). Both adults and children are impacted, while children may display unique vulnerabilities depending on the affected window of brain development.We aimed to use the advantages of high field proton Magnetic Resonance Spectroscopy ( <sup>1</sup> H MRS) to study longitudinally the neurometabolic and behavioural effects of Bile Duct Ligation (animal model of CLD-induced type C HE) on rats at post-natal day 15 (p15) to get closer to neonatal onset liver disease. Furthermore, we compared two sets of animals (p15 and p21-previously published) to evaluate whether the brain responds differently to CLD according to age onset.We showed for the first time that when CLD was acquired at p15, the rats presented the typical signs of CLD, i.e. rise in plasma bilirubin and ammonium, and developed the characteristic brain metabolic changes associated with type C HE (e.g. glutamine increase and osmolytes decrease). When compared to rats that acquired CLD at p21, p15 rats did not show any significant difference in plasma biochemistry, but displayed a delayed increase in brain glutamine and decrease in total-choline. The changes in neurotransmitters were milder than in p21 rats. Moreover, p15 rats showed an earlier increase in brain lactate and a different antioxidant response. These findings offer tentative pointers as to which neurodevelopmental processes may be impacted and raise the question of whether similar changes might exist in humans but are missed owing to <sup>1</sup> H MRS methodological limitations in field strength of clinical magnet

Propagation of hippocampal ripples to the neocortex by way of a subiculum-retrosplenial pathway

Bouts of high frequency activity known as sharp wave ripples (SPW-Rs) facilitate communication between the hippocampus and neocortex. However, the paths and mechanisms by which SPW-Rs broadcast their content are not well understood. Due to its anatomical positioning, the granular retrosplenial cortex (gRSC) may be a bridge for this hippocampo-cortical dialogue. Using silicon probe recordings in awake, head-fixed mice, we show the existence of SPW-R analogues in gRSC and demonstrate their coupling to hippocampal SPW-Rs. gRSC neurons reliably distinguished different subclasses of hippocampal SPW-Rs according to ensemble activity patterns in CA1. We demonstrate that this coupling is brain state-dependent, and delineate a topographically-organized anatomical pathway via VGlut2-expressing, bursty neurons in the subiculum. Optogenetic stimulation or inhibition of bursty subicular cells induced or reduced responses in superficial gRSC, respectively. These results identify a specific path and underlying mechanisms by which the hippocampus can convey neuronal content to the neocortex during SPW-Rs

Reinforcement of perfluoropolyethers coatings by ceramic oxides sol-gels for fouling mitigation on metal surfaces

In this research we developed a coating formulation containing \u3b1,\u3c9-substituted perfluoropolyethers (PFPE) and ceramic oxides sol-gels, for fouling mitigation on solid surfaces. Micrometer coatings where obtained on metal substrates by dip-coating procedure; they showed hydrophobic behavior (CA>130\ub0) and low CA hysteresis. The coatings resistance against shear stresses and chemicals increased thanks to the high mechanical properties of the ceramic oxides, compared to a simple PFPE coating. The ability of the coatings to mitigate particulate fouling was preliminary confirmed in presence of CaSO4 in an appropriate test rig. Motivations and Objectives One potential application of hydrophobic coatings concerns fouling mitigation. It has been demonstrated that low energy surfaces are able to influence the mechanism of deposition and removal of fouling particles on heat transfer surfaces, increasing the fouling induction period of the heat exchangers [1]. This research aims to develop a hydrophobic organic-inorganic coating, combining a PFPE with a sol-gel network obtained from the hydrolysis of tetraethylorthosilicate (OTES) or Zr-n-propoxide, in order to improve the mechanical properties of the final coatings. The investigation focuses the attention on the important coatings parameters for a possible application on heat transfer surfaces, i.e., thickness, thermal resistance, surface roughness and chemical and physical resistance. Fouling mitigation ability of the coatings is assessed in particulate fouling conditions, in a specific test rig. Hydrophobic coatings were obtained by formulating in iso-propanol a commercial PFPE (Fluorolink\uaeS10) with SiO2 or ZrO2 sol-gels, at different weight proportion (80/20, 1/05 and 1/1 respectively). The coatings resistance was investigated against erosion induced by liquid environments and shear stresses induced by a water flow. Compared to a simple PFPE coating, the resistance against shear stresses and aggressive environments increased of the 90%. Fouling mitigation ability of coatings deposited on the internal surfaces of a stainless steel tube, was assessed in presence of a CaSO4 solution (4 g/L), flowed inside a coated tube (temperature=40\ub0C, flowrate= 1.5 m/s). Thanks to the hydrophobic coating, the foulants deposition is 95% lower in respect to an uncoated surface

Aquivion® PFSA-based spray-freeze dried composite materials with SiO2 and TiO2 as hybrid catalysts for the gas phase dehydration of ethanol to ethylene in mild conditions

Aquivion PFSA resin, a perfluorinated ion-exchange polymer, has been used as a heterogeneous strong acid catalyst for a range of reactions; however, the activity of this material is limited due to the extremely low surface area of the polymer. In this paper we described the one-step synthesis of Aquivion® PFSA-based hybrid materials using heterocoagulation and spray-freeze-drying of sols containing the precursor of the active phases. The intimated encapsulation of different nano-oxides, such as TiO2 and SiO2 in the superacid resin matrix was easily obtained using this technique and compared with similar catalysts prepared by the impregnation conventional route. The approach led to the preparation of porous micro-granules characterised by a high homogeneity in the phase distribution and high surface area. The prepared materials were active and selective for the gas phase dehydration of ethanol to ethylene in mild conditions. The increase of the porosity improved the activity of the composites, compared to the pure Aquivion® PFSA, and allowed to reduce the amount of the superacid resin. Moreover, the type of encapsulated oxide, TiO2 or SiO2, modified the improved performance of the catalysts, having TiO2 the higher efficiency for ethanol conversion and selectivity in ethylene at very low temperature

Comet Machholz (C/2004 Q2): morphological structures in the inner coma and rotation parameters

Extensive observations of comet C/2004 Q2 (Machholz) were carried out between August 2004 and May 2005. The images obtained were used to investigate the comet's inner coma features at resolutions between 350 and 1500 km/pixel. A photometric analysis of the dust outflowing from the comet's nucleus and the study of the motion of the morphological structures in the inner coma indicated that the rotation period of the nucleus was most likely around 0.74 days. A thorough investigation of the inner coma morphology allowed us to observe two main active sources on the comet's nucleus, at a latitude of +85{\deg} \pm 5{\deg} and +45{\deg} \pm 5{\deg}, respectively. Further sources have been observed, but their activity ran out quite rapidly over time; the most relevant was at latcom. = 25{\deg} \pm 5{\deg}. Graphic simulations of the geometrical conditions of observation of the inner coma were compared with the images and used to determine a pole orientation at RA=95{\deg} \pm 5{\deg}, Dec=+35{\deg} \pm 5{\deg}. The comet's spin axis was lying nearly on the plane of the sky during the first decade of December 2004.Comment: 29 pages, 8 figures, 3 table

IRSp53 controls plasma membrane shape and polarized transport at the nascent lumen in epithelial tubules

It is unclear whether the establishment of apical\u2013basal cell polarity during the generation of epithelial lumens requires molecules acting at the plasma membrane/actin interface. Here, we show that the I-BAR-containing IRSp53 protein controls lumen formation and the positioning of the polarity determinants aPKC and podocalyxin. Molecularly, IRSp53 acts by regulating the localization and activity of the small GTPase RAB35, and by interacting with the actin capping protein EPS8. Using correlative light and electron microscopy, we further show that IRSp53 ensures the shape and continuity of the opposing plasma membrane of two daughter cells, leading to the formation of a single apical lumen. Genetic removal of IRSp53 results in abnormal renal tubulogenesis, with altered tubular polarity and architectural organization. Thus, IRSp53 acts as a membrane curvature-sensing platform for the assembly of multi-protein complexes that control the trafficking of apical determinants and the integrity of the luminal plasma membrane