Prototype and Chimera-Type Galectins in Placentas with Spontaneous and Recurrent Miscarriages

Galectins are galactose binding proteins and, in addition, factors for a wide range of pathologies in pregnancy. We have analyzed the expression of prototype (gal-1, -2, -7, -10) and chimera-type (gal-3) galectins in the placenta in cases of spontaneous abortions (SPA) and recurrent abortions (RA) in the first trimester. Fifteen placental samples from healthy pregnancies were used as a control group. Nine placentas were examined for spontaneous abortions, and 12 placentas for recurrent abortions. For differentiation and evaluation of different cell types of galectin-expression in the decidua, immunofluorescence was used. For all investigated prototype galectins (gal-1, -2, -7, -10) in SPA and RA placenta trophoblast cells the expression is significantly decreased. In the decidua/extravillous trophoblast only gal-2 expression was significantly lowered, which could be connected to its role in angiogenesis. In trophoblasts in first-trimester placentas and in cases of SPA and RA, prototype galectins are altered in the same way. We suspect prototype galectins have a similar function in placental tissue because of their common biochemical structure. Expression of galectin 3 as a chimera type galectin was not found to be significantly altered in abortive placentas.     

Copper(I/II), α/β‐Synuclein and Amyloid‐β: Menage à Trois?

Copper binding to α‐synuclein (aS) and to amyloid‐β (Ab) has been connected to Parkinson's and Alzheimer's disease (AD), respectively, because Cu ions can modulate the peptide aggregation, and these Cu ? peptide complexes can catalyse the production of reactive oxygen species (ROS). In a significant proportion of AD brains, aggregation of aS and Ab has been detected, and it was proposed that Ab and aS interact with each other. Thus, we investigated the potential interactions of Ab and aS through their binding of copper(I) and copper(II). Additionally, β‐synuclein (bS) was investigated, due to its additional methionine residue, a potential Cu^I ligand. We found that: 1) the peptides containing the Cu‐binding domains Ab1–16, aS1–15 and bS1–15 have similar affinities towards Cu^II and towards Cu^I, with Ab1–16 being slightly stronger, 2) in the case of Cu^I, the additional Met residue in bS1–15 increased the affinity slightly, 3) the exchange of Cu^I/II between the two peptides is rapid (≤ms), 4) a/bS1–15 and Ab1–16 form a heterodimeric complex with Cu^II, 5) Cu^I probably promotes a transient ternary complex, 6) the different Cu^I/II coordination of Ab1–16, aS1–15 and bS1–15 impacts the capacity to produce ROS and to oxidise catechol, and 7) when Ab1–16, aS1–15 and Cu are present, the ROS production more closely resembles that by Ab1–16. The work gives insights into the coordination chemistry of these related peptides, and the relevance of coordination differences, the ternary complex and ROS production are discussed.     

Small and large scale segmental motion in polymers: estimating cooperativity length by ordinary relaxation experiments

We derive a suitable expression for estimating the size of the cooperatively rearranging regions (CRRs) in supercooled polymer melts by fitting data worked out by ordinary relaxation experiments carried out in isothermal conditions. As an example, the average CRR size in poly(n‐butyl methacrylate) in proximity to the glass transition temperature is derived from a stress relaxation experiment performed by means of an atomic force microscopy setup. Good agreement is found with results in the literature derived from measurements of temperature fluctuations (the so‐called Donth method). The temperature dependence of the CRR size is explored for poly(butadiene); in this case the segmental relaxation function is derived through a novel method for the analysis of the efficiency with which free induction decay echoes are refocused in ¹H NMR experiments. It is found that the CRR size increases upon cooling. The results derived from the analysis of the NMR data are found to be in satisfactory agreement with those worked out from broadband dielectric spectroscopy data in the literature. © 2015 Society of Chemical Industry     

THE USE OF A GAS CHROMATOGRAPH TO OBTAIN DRYING RATES DATA THROUGH SIMPLE LABORATORY EXPERIMENTS

Abstract

A method making use of a gas chromatograph was investigated to acquire bound solvent drying rates. The solid to be dried was used as stationary phase in a chromatographic column, and the TCD detector was used to follow the decrease of solvent content of the effluent as inert gas was flown through the column. The measurement of the break-through curve allows the evolution of drying rate with time or solvent content to be obtained. The comparison of the experimental results with numerical simulation leads to the determination, through parametric adjustment, of the internal mass-transfer coefficient as a function of the solvent content during the second stage of bound solvent drying period. This parameter can lead to the value of the diffusivity as a function of solvent content.     

Preparation and characterization of poly(vinyl chloride)/polystyrene/poly(ethylene glycol) hollow‐fiber ultrafiltration membranes

Hollow‐fiber ultrafiltration (UF) membranes were prepared from blends of poly(vinyl chloride) (PVC) and polystyrene (PS) with a dry/wet phase inversion method. Poly(ethylene glycol) (PEG) and N,N‐dimethylacetamide were used as the additive and solvent, respectively. The effects of the PEG concentration in the dope solution as an additive on the cross sections and inner and outer surface morphologies, permeability, and separation performance of the hollow fibers were examined. The mean pore size, pore size distribution, and mean roughness of both the inner and outer surfaces of the produced hollow fibers were determined by atomic force microscopy. Also, the mechanical properties of the hollow‐fiber membranes were investigated. UF experiments were conducted with aqueous solutions of poly(vinyl pyrrolidone) (PVP; K‐90, M_w = 360 kDa). From the results, we found that the PVC/PS hollow‐fiber membranes had two layers with a fingerlike structure. These two layers were changed from a wide and long to a thin and short morphology with increasing PEG concentration. A novel and until now undescribed shape of the nodules in the outer surfaces, which was denoted as a sea‐waves shape, was observed. The outer and inner pore sizes both increased with increasing PEG concentration. The water permeation flux of the hollow fibers increased from 104 to 367 L m^?2 h^?1 bar^?1) at higher PEG concentrations. The PVP rejection reached the highest value at a PEG concentration of 4 wt %, whereas at higher values (from 4 to 9 wt %), the rejection decreased. The same trend was found also for the tensile stress at break, Young's modulus, and elongation at break of the hollow fibers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 989‐1004, 2013     

Thermal Degradation Kinetics of Carotenoids in Palm Oil

In the present work, a detailed study is performed for carotene thermal degradation in palm oil at four temperatures ranging from 170 to 230 °C. The heating process was carried out with injection of nitrogen, and the samples were collected every 20 min during a total heating period of 140 min. HPLC analysis was conducted to monitor the carotenoids and tocols variations over the heating time at each temperature. The experimental data were then compared to literature data concerning carotenoids thermal degradation. The thermal degradation kinetics of carotenoids in palm oil followed an order superior to 1. The dependence of constant rates with temperature obeyed the Arrhenius relationship. The activation energy for the carotenoids thermal degradation in palm oil was found to be 109.4 kJ/mol.