Diphtheria immunity in Flanders

A serological survey to determine the immunity to diphtheria in the Flemish population was conducted according to the recommendations of the World Health Organization. Immunity to diphtheria was determined on a randomised, stratified sample (1679 serum samples) from an existing serum bank (4058 serum samples) representative of the Flemish population. All age groups between 0 and 100 years were included. A tissue (Vero cell) culture toxin neutralisation assay was used to measure serum diph-theria antitoxin concentrations. The results showed that 43% of the Flemish population was protected against diphtheria (antitoxin titre, > or = 0.1 IU/ml), while 32% was susceptible (antitoxin titre, < 0.01 IU/ml); for 25%, protection was of limited duration (antitoxin titre, > or = 0.01 IU/ml and < 0.1 IU/ml). The proportion of susceptible subjects showed a significant age-related increase, with the highest values in the 35 to 44 and 45 to 54 age groups (57.9% and 55.5%, respectively). These results emphasise the need for booster immunization of adults.     

Early and late effects of absorbable poly(vinyl alcohol) hernia mesh to tissue reconstruction

Hernia is a defect of the abdominal wall. Treatment is principally surgical mesh implantation. Non‐degradable surgical meshes produce numerous complications and side‐effects such as inflammatory response, mesh migration and chronic pain. In contrast, the biodegradable, poly (vinyl alcohol) (PVA) based polymers have excellent chemical, mechanical and biological properties and after their degradation no chronic pain can be expected. The toxicology of PVA solution and fibers was investigated with Human dermal fibroblast‐ Adult cell line. Implantation tests were observed on long‐term contact (rat) and large animal (swine) models. To measure the adhesion formation, Diamond and Vandendael score were used. Macroscopical and histological responses were graded from the samples. In vitro examination showed that PVA solution and fibers are biocompatible for the cells. According to the implantation tests, all samples were integrated into the surrounding tissue, and there was no foreign body reaction. The average number of adhesions was found on the non‐absorbable suture line. The biocompatibility of the PVA nanofiber mesh was demonstrated. It has a non‐adhesive, non‐toxic and good quality structure which has the potential to be an alternative solution for the part of the hernia mesh.     

Double cross-linked polyetheretherketone proton exchange membrane for fuel cell

The proton exchange membrane based on polyetheretherketone was prepared via two steps of cross-linking. The properties of the double cross-linked membrane (water uptake, proton conductivity, methanol permeability and thermal stability) have been investigated for fuel cell applications. The prepared membrane exhibited relatively high proton conductivity, 3.2 × 10⁻² S cm⁻¹ at room temperature and 5.8 × 10⁻² S cm⁻¹ at 80 °C. The second cross-linking significantly decreased the water uptake of the membrane. The performance of direct methanol fuel cell was slightly improved as compared to Nafion^® 117 due to its low methanol permeability. The results indicated that the double cross-linked membrane is a promising candidate for the polymer electrolyte membrane fuel cell, especially for the direct methanol fuel cell due to its low methanol permeability and high stability in a methanol solution.     

Magnetic properties of nanocrystalline CoFe2O4 synthesized by thermal plasma in large scale

The paper reports the large scale synthesis of nanoparticles of CoFe₂O₄ using thermal plasma reactor by gas phase condensation method. The yield of formation was found to be around 15 g h⁻¹. The magnetic properties of CoFe₂O₄, synthesized at different reactor powers, were investigated in view of studying the effect of operating parameters of plasma reactor on the structural reorganization leading to the different cation distribution. The values of saturation magnetization, coercivity and remanent magnetization were found to be influenced by input power in thermal plasma. Although the increase in saturation magnetization was marginal (61 emu g⁻¹ to 70 emu g⁻¹) with increasing plasma power; a significant increase in the coercivity (552 Oe to 849 Oe) and remanent magnetization (16 emu g⁻¹ to 26 emu g⁻¹) were also noticed. The Mössbauer spectra showed mixed spinel structure and canted spin order for the as synthesized nanoparticles. The detailed analysis of cation distribution using the Mössbauer spectroscopy and X-ray photoelectron spectroscopy leads to the conclusion that the sample synthesized at an optimized power shows the different site selective states.     

Enhanced conductivity and stability of composite membranes based on poly (2,5-benzimidazole) and zirconium oxide nanoparticles for fuel cells

Poly (2,5-benzimidazole) (ABPBI) and zirconium oxide (ZrO₂) nanoparticles composite membranes were synthesized. These membranes can be fabricated into tough, dense membranes by blending Poly (2,5-benzimidazole) (ABPBI) with zirconium oxide (ZrO₂) nanoparticles, which were characterized by using FTIR, XRD, SEM, TGA, DSC and tensile test. These composite membranes showed increased conductivity compared with original ABPBI membrane. Maximum proton conductivity at 100 °C was found to be 0.069 S cm⁻¹ on 10% ZrO₂ incorporated ABPBI composite membrane, almost four times as high as the 0.018 S cm⁻¹ obtained in the case of the ABPBI membrane. The conductivity was 0.0325 S cm⁻¹ at 180 °C in dry condition for ABPBI with 10% ZrO₂ nanoparticles composite membrane, higher than the conductivity 0.011 S cm⁻¹ of the ABPBI membrane at same condition. Furthermore, the composite membranes were shown to have high thermal and mechanical stability. These results suggest that ABPBI/ZrO₂ composite membranes may be a promising polymer electrolyte for fuel cells at medium or high temperature, due to their strong physical properties.     

Dehydrogenation of methanol to methyl formate: deuterium labeling studies

Different synthetic AlPO₄ systems are effective yet mild acid catalysts for the heterogeneous cycloaddition reaction of cyclopentadiene with (-)-menthyl acrylate. The reaction proceeds selectively under mild conditions and in a relatively short reaction time with an almost total conversion, a high endo/exo ratio, and a reasonable asymmetric induction. When the reactions are carried out without solvent, some correlations are obtained between the number of acid sites, titrated with pyridine, and reaction yields, endo/exo and diastereofacial selectivities. The positive influence of surface area of catalysts is also determined. However, the lack of good correlations between reaction results and surface properties of the catalysts indicates the influence of some other factors.     

Low‐Power and Low‐Hardware Bit‐Parallel Polynomial Basis Systolic Multiplier over GF(2m) for Irreducible Polynomials

Multiplication in finite fields is used in many applications, especially in cryptography. It is a basic and the most computationally intensive operation from among all such operations. Several systolic multipliers are proposed in the literature that offer low hardware complexity or high speed. In this paper, a bit‐parallel polynomial basis systolic multiplier for generic irreducible polynomials is proposed based on a modified interleaved multiplication method. The hardware complexity and delay of the proposed multiplier are estimated, and a comparison with the corresponding multipliers available in the literature is presented. Of the corresponding multipliers, the proposed multiplier achieves a reduction in the hardware complexity of up to 20% when compared to the best multiplier for m = 163. The synthesis results of application‐specific integrated circuit and field‐programmable gate array implementations of the proposed multiplier are also presented. From the synthesis results, it is inferred that the proposed multiplier achieves low power consumption and low area complexitywhen compared to the best of the corresponding multipliers.     

Chemical characterization and origin of dyes used in the manufacture of Beninese cultural heritage objects

Six objects of Beninese cultural heritage provided by African and Confluences museums of Lyon (France) were the focus of this study. The characterization of colored compounds was achieved using: microchemical tests, Fourier transform infrared spectroscopy and liquid chromatography coupled to a photodiode array detector. The main results reflect the presence of organic compounds like indigotin, 2‐hydroxynaphthoquinone, and mineral ions such as Al³⁺, S^2?, Na⁺, and Fe³⁺. Dyes were identified from Philenoptera cyanescens (Yoruba indigo) and Lawsonia inermis L. (henna); pigments were identified as laundry blue, Prussian blue, and iron oxides. All of these data therefore make possible the conservation and the restoration of these objects while maintaining their visual and functional integrity.