Oleic acid‐based poly(alkyl methacrylate) as bio‐based viscosity control additive for mineral and vegetable oils

This work described the design of an efficient oleic‐acid based viscosity control additive for lubricating oils as potential alternative to petroleum poly(alkyl)methacrylates (PAMAs) additives. Hence, Poly(2‐(methacryloyloxy)ethyl oleate) (PMAEO) was synthesized by free radical homopolymerization to afford a comb‐like polymer structure similar to common PAMAs. Then, in order to evaluate its efficiency as viscosity control additive, the resulting polymer was mixed at several concentrations from 1%wt to 10%wt with different oil compositions, including a mineral paraffinic oil (MPO) and an organic triglyceride oil (OTO). For all polymer‐solution blends, relative viscosities (RV) measurements showed that addition of PMAEO in MPO had a better contribution on oil viscosity at 100°C than at 20°C (RV = 1.16 at 40°C while RV = 1.25 for 3%wt of PMAEO in MPO). These results were attributed to the coil expansion of polymer chains with increasing temperature. Additionally, rheological studies showed that addition of 3%wt of PMAEO in MPO improved the MPO cold flow properties at ?30°C by decreasing the required yield stress to put the oil in motion from 310 mPa to 42 mPa. These results are in total accordance with the common viscosimetric properties of PAMAs‐based viscosity control additives at low and high temperature in mineral oils. POLYM. ENG. SCI., 59:E164–E170, 2019. © 2018 Society of Plastics Engineers     

Intravenous calcium infusion in a calving protocol disrupts calcium homeostasis compared with an oral calcium supplement

Hypocalcemia is a common postpartum condition in dairy cows, which negatively affects health and production. Intravenous Ca infusions are commonly included in calving protocols to prevent or mitigate the effect of hypocalcemia in multiparous cows. Thus, we sought to contrast the effect of intravenous Ca infusion against voluntary oral Ca intake on Ca metabolism. Serum total Ca (tCa) and whole-blood ionized Ca (iCa) were monitored in 24 multiparous Holstein cows after parturition. Precalving diets were formulated with a positive dietary cation-anion difference of 172 mEq/kg of DM and contained 4.1 g of Ca/kg of DM. At parturition, cows were blocked by calving sequence and calcemic status as either normocalcemic (cutoff threshold of iCa ≥1.10 mmol/L) or hypocalcemic (cutoff threshold of iCa <1.10 mmol/L). Cows in each block were randomly assigned to 1 of 2 treatments: either an oral source of Ca (Ca-Oral; n = 12) or an intravenous source of Ca (Ca-IV; n = 12). Cows in the Ca-Oral group were offered a 20-L commercial Ca suspension (48 g of Ca) for voluntary consumption. The supplement contained Ca carbonate, Ca formate, Ca propionate, and other minerals and vitamins (Farm-O-San Reviva, Trouw Nutrition, Amersfoort, the Netherlands). Cows in the Ca-IV group received a 450-mL intravenous Ca solution (13 g of Ca) that contained 298 mg/mL of Ca gluconate, 33 mg/mL of magnesium chloride, and 82 mg/mL of boric acid (AmosCAL, Kommer-Biopharm BV, Heiloo, the Netherlands). Both treatments were initiated within 25 ± 10 min after calving. The oral Ca suspension was offered to cows in a 25-L bucket and was available for 10 min. All cows in the Ca-Oral group voluntarily consumed the entire 20 L of the Ca suspension within 5 min. Blood samples for Ca analyses were collected at 0 (before treatment initiation), 1, 3, 10, and 18 h relative to treatment, and at 0700 and 1900 h for the next 2 consecutive days, to represent the 24-, 36-, 48-, and 60-h sampling time points. In Ca-IV cows, both iCa and tCa concentrations peaked at 1 h (1.54 mmol/L for iCa and 2.85 mmol/L for tCa) and declined to a nadir at 24 h following treatment initiation (0.94 mmol/L for iCa and 1.74 mmol/L for tCa). Although whole-blood iCa and serum tCa were higher at 1 and 3 h in Ca-IV cows, concentrations of iCa were greater for Ca-Oral cows at 18, 24, and 36 h and for tCa at 24 and 36 h. Our data indicate that intravenous Ca infusion immediately induced a state of hypercalcemia followed by lower whole-blood iCa and serum tCa concentrations 24 h later compared with oral Ca.     

A New Role for Plastid Thioredoxins in Seed Physiology in Relation to Hormone Regulation

In Arabidopsis seeds, ROS have been shown to be enabling actors of cellular signaling pathways promoting germination, but their accumulation under stress conditions or during aging leads to a decrease in the ability to germinate. Previous biochemical work revealed that a specific class of plastid thioredoxins (Trxs), the y-type Trxs, can fulfill antioxidant functions. Among the ten plastidial Trx isoforms identified in Arabidopsis, Trx y1 mRNA is the most abundant in dry seeds. We hypothesized that Trx y1 and Trx y2 would play an important role in seed physiology as antioxidants. Using reverse genetics, we found important changes in the corresponding Arabidopsis mutant seeds. They display remarkable traits such as increased longevity and higher and faster germination in conditions of reduced water availability or oxidative stress. These phenotypes suggest that Trxs y do not play an antioxidant role in seeds, as further evidenced by no changes in global ROS contents and protein redox status found in the corresponding mutant seeds. Instead, we provide evidence that marker genes of ABA and GAs pathways are perturbed in mutant seeds, together with their sensitivity to specific hormone inhibitors. Altogether, our results suggest that Trxs y function in Arabidopsis seeds is not linked to their previously identified antioxidant roles and reveal a new role for plastid Trxs linked to hormone regulation.     

Etude a haute temperature des systemes formes par le sesquioxyde de neodyme avec les sesquioxydes d'yttrium et d'ytterbium

The systems formed by neodymium sesquioxide with respectively yttrium sesquioxide and ytterbium sesquioxide showed several very extended solid solutions at high temperature, near the melting point. The phases determined “in situ” at high temperature are often different of those obtained in annealed or quenched samples.     

Mutational equations of the morphological dilation tubes

The present paper provides some differential results dealing with the morphological dilation of a compact set in the nonregular case. Indeed the evolution of dilated sets with respect to time is characterized through mutational equations which are new mathematical tools extending the concept of differential equations to the metric space of all nonempty compact sets of ⁿ . Using this new tool, we prove that the mutation of the dilation is the normal cone which is a generalization of the classical notion of normal. This result clearly establishes that the dilation transforms this initial set in the direction of the normal at any point of the set. Furthermore, it does not require any regularity assumptions on the compact set.     

Characterization of mesoporous alumina prepared by surface alumination of SBA-15

Mesoporous aluminas of controlled pore sizes were synthesized by multiple grafting of Al isopropoxide in organic solvents on mesoporous silica SBA-15. These materials were characterized by N₂ physisorption, TEM, XRD, ²⁷Al NMR and their surface chemical properties were probed by DRIFT, cumene cracking and MoO₃ thermal spreading. The results show that the chemical nature of the Al-grafted materials varies continuously with the number of grafting from pure silica to pure alumina. Typically, after three graftings, this original method of synthesis allows one to prepare ordered mesoporous aluminas with specific surface areas above 300 m² g⁻¹ and a narrow pore size distribution centered on ca. 60 Å. In addition to the characterizations, different models were developed to understand the evolution of the specific surface area and to discard a possible pore blocking.     

Preparation of Ru metal nanoparticles in mesoporous materials: influence of sulfur on the hydrogenating activity

Hydrogenating catalysts were prepared by inserting Ru into the pores of mesoporous Al-MCM-41 materials by selective adsorption of [Ru(NH₃)₆]³⁺. Ru/support catalysts were obtained after reduction with H₂. The activities of these catalysts in hydrogenation reactions were compared to those of Ru/HY and Ru/SiO₂. The catalytic properties in the absence of sulfur were tested in benzene hydrogenation, and the intrinsic activities of all the catalysts (either supported on mesoporous materials or on zeolites) were identical. It was concluded from this result that the dispersion of the Ru metallic phase was similar for all these catalysts. These samples were tested in the tetralin hydrogenation in pure H₂ and in the presence of H₂S (330 ppm of H₂S in H₂). They were found to be much less active than the zeolite-supported catalysts in the presence of H₂S. It is proposed that the lower activity of the catalysts supported on mesoporous materials is either due to their milder acidity, as evidenced by NH₃-TPD, cumene cracking and pyridine desorption experiments, or to the localization of the Ru nanoparticles on alumina islands.