Electrical probing of endothelial cell behaviour on a fibronectin/polystyrene/thiol/gold electrode by Faradaic electrochemical impedance spectroscopy (EIS)

The electrochemical impedance spectroscopy (EIS) technique has been shown to be an effective tool for monitoring endothelial cell behaviour on a multilayer functionalised gold electrode. Polystyrene, a reproducible model substrate, is deposited as a thin layer on a thiol functionalised gold electrode. Fibronectin, a protein promoting endothelial cell adhesion, is then adsorbed on the polystyrene surface. The different steps of this multilayer assembly are characterized by Faradaic impedance. The charge transfer resistance and the capacitance for the total layer are modified at each step according to the electrical properties of each layer. This gives the endothelial cells' electrical state in terms of its resistive and capacitive properties. In this study, the endothelial cell layer presents a specific charge transfer resistance equal to 1.55 kOmega cm(2) with no large defects in the cell layer, and a specific capacitance equal to few microF cm(-2) explained by the existence of pseudopods. These electrical properties are correlated to the endothelial cell viability, adhesion and cytoskeleton organization.     

Chemical compounds from Phoenician juniper berries (Juniperus phoenicea)

Natural chemical compounds are a widely researched topic worldwide because of their potential activity against cerebrovascular diseases. Chemicals from Juniperus phoenicea berries are reported in this study. Lipids (11%) from seeds are mainly unsaturated (86%). Minerals are also quantified like Na (63.8?mg per 100?g?DW) or K (373.9?mg per 100?g?DW). Total reduced sugars are ca 192.6?mg?g(-1)?DW. Polyphenols and flavonoids from berries are highly present with an average of 1764?±?174.3?mg gallic acid per 100?g?DW and 890?±?47.6?mg rutin per 100?g?DW, respectively. Mean free radical scavenging activities, determined by DPPH and ABTS, are 1337?±?126.2?mM TEAC per 100?g?DW and 1105.7?±?95.9?mM TEAC per 100?g?DW, respectively. All findings improve the possible presence of biologically active fractions in phytocomplex that could be used as such and/or extracted for the formulation of supplements and/or ingredients for the pharmaceutical industry.     

Bernstein–Sato polynomials of hyperplane arrangements

We show that the Bernstein–Sato polynomial (that is, the b-function) of a hyperplane arrangement with a reduced equation is calculable by combining a generalization of Malgrange’s formula with the theory of Aomoto complexes due to Esnault, Schechtman, Terao, Varchenko, and Viehweg in certain cases. We prove in general that the roots are greater than \(-2\) and the multiplicity of the root \(-1\) is equal to the (effective) dimension of the ambient space. We also give an estimate of the multiplicities of the roots in terms of the multiplicities of the arrangement at the dense edges, and provide a method to calculate the Bernstein–Sato polynomial at least in the case of 3 variables with degree at most 7 and generic multiplicities at most 3. Using our argument, we can terminate the proof of a conjecture of Denef and Loeser on the relation between the topological zeta function and the Bernstein–Sato polynomial of a reduced hyperplane arrangement in the 3 variable case.     

Mixed Hodge complexes on algebraic varieties

Using the theory of mixed Hodge Modules, we introduce the notion of mixed Hodge complex on an algebraic variety, and establish the relation between the filtered complex of Du Bois and the corresponding complex of mixed Hodge Modules. Some application to the Du Bois singularity is given. Received: 20 February 1999     

Comparison of Different d-SPE Sorbent Performances Based on Quick,Easy, Cheap,Effective, Rugged,and Safe (QuEChERS) Methodology for Multiresidue Pesticide Analyses in Rapeseeds

Pesticide extraction in rapeseed samples remains a great analytical challenge due to the complexity of the matrix, which contains proteins, fatty acids, high amounts of triglycerides and cellulosic fibers. An HPLC-MS/MS method was developed for the quantification of 179 pesticides in rapeseeds. The performances of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method were evaluated using different dispersive solid-phase extraction (d-SPE) sorbents containing common octadecylsilane silica/primary–secondary amine adsorbent (PSA/C18) and new commercialized d-SPE materials dedicated to fatty matrices (Z-Sep, Z-Sep⁺, and EMR-Lipid). The analytical performances of these different sorbents were compared according to the SANTE/12682/2019 document. The best results were obtained using EMR-Lipid in terms of pesticide average recoveries (103 and 70 of the 179 targeted pesticides exhibited recoveries within 70–120% and 30–70%, respectively, with low RSD values). Moreover, the limits of quantification (LOQ) range from 1.72 µg/kg to 6.39 µg/kg for 173 of the pesticides. Only the recovery for tralkoxydim at 10 μg/kg level was not satisfactory (29%). The matrix effect was evaluated and proved to be limited between −50% and 50% for 169 pesticides with this EMR-Lipid and freezing. GC-Orbitrap analyses confirmed the best efficiency of the EMR-Lipid sorbent for the purification of rapeseeds.