Polyamide from lactams by reactive rotational molding via anionic ring-opening polymerization: Optimization of processing parameters

A reactive rotational molding (RRM) process was developed to obtain a PA6 by activated anionic ring-opening polymerization of epsilon-caprolactam (APA6). Sodium caprolactamate (C10) and caprolactam magnesium bromide (C1) were employed as catalysts, and difunctional hexamethylene-1,6-dicarbamoylcaprolactam (C20) was used as an activator. The kinetics of the anionic polymerization of !-caprolactam into polyamide 6 was monitored through dynamic rheology and differential scanning calorimetry measurements. The effect of the processing parameters, such as the polymerization temperature, different catalyst/activator combinations and concentrations, on the kinetics of polymerization is discussed. A temperature of 150°C was demonstrated to be the most appropriate. It was also found that crystallization may occur during PA6 polymerization and that the combination C1/C20 was well suited as it permitted a suitable induction time. Isoviscosity curves were drawn in order to determine the available processing window for RRM. The properties of the obtained APA6 were compared with those of a conventionally rotomolded PA6. Results pointed at lower cycle times and increased tensile properties at weak deformation

Structural Study of the Compound [(C10O8H2)2 (C4N2H6)].2H2O Synthesized by Hydrothermal Condition

A new metal–organic compound [(C10O8H2)2(C4N2H6)].2H2O(I) was hydrothermally synthesized from an aqueous solution of Fe (NO3)3 9H2O, (btec) (btec= 1, 2, 4, 5-benzenetetracarboxylic acid) and piperazine. Compound I crystallizes in the triclinic system with the P1 space group. The unit cell parameters are a = 8.271 Å, b = 8.500 Å, c = 9.660 Å, α = 87.12°, β = 89.53°, γ = 70.91°, Z= 2, V= 640.96(6) Å3 and Dx= 1.602g/cm3. The refinement converged into R= 0.047 and RW = 0.059. The structure, determined by single crystal X-ray diffraction, consists of two carboxyl group, piperazine and two molecules of water

Growth factor concentrations and their placental mRNA expression are modulated in gestational diabetes mellitus: possible interactions with macrosomia

<p>Abstract</p> <p>Background</p> <p>Gestational diabetes mellitus (GDM) is a form of diabetes that occurs during pregnancy. GDM is a well known risk factor for foetal overgrowth, termed macrosomia which is influenced by maternal hypergycemia and endocrine status through placental circulation. The study was undertaken to investigate the implication of growth factors and their receptors in GDM and macrosomia, and to discuss the role of the materno-foeto-placental axis in the <it>in-utero </it>regulation of foetal growth.</p> <p>Methods</p> <p>30 women with GDM and their 30 macrosomic babies (4.75 ± 0.15 kg), and 30 healthy age-matched pregnant women and their 30 newborns (3.50 ± 0.10 kg) were recruited in the present study. Serum concentrations of GH and growth factors, <it>i.e</it>., IGF-I, IGF-BP3, FGF-2, EGF and PDGF-B were determined by ELISA. The expression of mRNA encoding for GH, IGF-I, IGF-BP3, FGF-2, PDGF-B and EGF, and their receptors, <it>i.e</it>., GHR, IGF-IR, FGF-2R, EGFR and PDGFR-β were quantified by using RT-qPCR.</p> <p>Results</p> <p>The serum concentrations of IGF-I, IGF-BP3, EGF, FGF-2 and PDGF-B were higher in GDM women and their macrosomic babies as compared to their respective controls. The placental mRNA expression of the growth factors was either upregulated (FGF-2 or PDGF-B) or remained unaltered (IGF-I and EGF) in the placenta of GDM women. The mRNA expression of three growth factor receptors, <it>i.e</it>., IGF-IR, EGFR and PDGFR-β, was upregulated in the placenta of GDM women. Interestingly, serum concentrations of GH were downregulated in the GDM women and their macrosomic offspring. Besides, the expression of mRNAs encoding for GHR was higher, but that encoding for GH was lower, in the placenta of GDM women than control women.</p> <p>Conclusions</p> <p>Our results demonstrate that growth factors might be implicated in GDM and, in part, in the pathology of macrosomia via materno-foeto-placental axis.</p

Smectite clay KSF as effective catalyst for oxidation of m-tyrosol with H 2 O 2 to hydroxytyrosol

A successful procedure to demonstrate the ability to produce high-added value phenolic hydroxytyrosol by oxidation of m-tyrosol was developed, using clay KSF/H 2 O with peroxide hydrogen to afford excellent yields (more than 60%). Three different operating parameters, including m-tyrosol, H 2 O 2 concentration and amount of catalyst were performed using an experimental design methodology “Box–Behnken” for hydroxytyrosol production. All derivative compounds in reaction mixture during reaction time were identified using mass spectrometry. Hydroxytyrosol 3,4-dihydroxystyrene; 3-hydroxyphenyl acetic acid and 2.5-dihydroxyphenylethanol were the major compounds. By means of 2,2-diphenyl-1-picrylhydrazyl DPPH method, the antioxidant activity was realized, indicating that the strongest antiradical activity (IC 50% = 21.57 mg/mL) was detected when the concentration of hydroxytyrosol is higher. The developed synthesis, investigated for the first time, is operationally simple and could find application for industrial purposes. © 2019, Akadémiai Kiadó, Budapest, Hungary

Applying a Model-Driven Approach for UML/OCL Constraints: Application to NoSQL Databases

International audienceBig Data have received a great deal of attention in recent years. Not only the amount of data is on a completely different level than before, but also we have different type of data including factors such as format, structure, and sources. This has definitely changed the tools we need to handle Big Data, giving rise to NoSQL systems. While NoSQL systems have proven their efficiency to handle Big Data, it’s still an unsolved problem how the automatic storage of Big Data in NoSQL systems could be done. This paper proposes an automatic approach for implementing UML conceptual models in NoSQL systems, including the mapping of the associated OCL constraints to the code required for checking them. In order to demonstrate the practical applicability of our work, we have realized it in a tool supporting four fundamental OCL expressions: Iterate-based expressions, OCL predefined operations, If expression and Let expression