Nanocrystallization by nitriding treatment of FeSiB-based amorphous ribbons

In FeSiB-based systems, nanocrystalline state needed for good soft magnetic properties is obtained by controlling nucleation and growth rates of crystallization. These rates are known to depend on the additive elements in the FeSiB alloys but also on the annealing treatment. Generally, Cu and Nb are chosen as additive elements and conventional thermal treatment (C.T.T.) is used to produce the nanocrystalline phase. In this work, we studied Fe73.5Cu1Si13.5B12, Fe74Nb3Si14B9 and Fe73.5Cu1Nb3Si13.5B9 ribbons. To obtain the nanocrystalline state, in addition to C.T.T., we used a nitriding thermochemical treatment (N.T.T.) at =520°C and we show that this treatment improves the nanocrystalline state (smaller grain size D and higher crystalline volume fraction. This treatment also increases the Curie temperature of the crystalline α-FeSi phase

A comparison of native state of casein micelles of buffalo and cow milk and its molecularchanges under different physico-chemical conditions

Buffalo milk is the second most produced milk in the world after cow milk with about 13% (89.3out of 693.7 billion litres) contribution in the world’s milk production. Buffalo milk increased ata double rate as compared to cow’s during last decade at global level. 92% of this milk isproduced in India and Pakistan. This milk is majorly handled by “informal sector” in all itsproducing countries except Italy.Quantitatively, buffalo milk is richer in all major constituents like fat, lactose, minerals andproteins particularly in casein contents than that of cow milk (casein concentration of buffalomilk is equivalent to total protein concentration of cow milk). Caseins are present in the form ofsupramolecular spherical colloidal structures named casein micelles like other milks. Caseinmicelles play a key role in milk for its biological and technological functionalities. Despite of lotof literature on casein micelles of cow milk, its micellar organization and dynamics are not wellknown whereas the knowledge on casein micelles of buffalo milk is even far less especially in itsnative state and under different physico-chemical conditions.The objective of this study was to gain knowledge on casein micelles of buffalo milk in its nativestate and its molecular changes as a function of different physico-chemical conditions (ionicstrength, acidification, alkalinisation, microfiltration/diafiltration and heat-treatments). Thecomparison with casein micelles of cow milk was used as a reference throughout the study.Biochemical, physic-chemical, molecular, microscopic, macroscopic, physical and organolepticapproaches were used to compare casein micelles of both milks. The proportion of casein/solubleproteins was 80/20 in both milks. In native state, casein micelles of buffalo milk were higher inconcentration, bigger in size, less hydrated, more mineralized as compared to casein micelles ofcow milk with similar charge and casein classes. The comparison of amino acids sequences ofcasein micelles showed a homology of 95% in both milks which globally depicts the similarmolecular organization of caseins. Casein micelles showed similar behavior against differentphysic-chemical conditions like cow milk qualitatively but due to quantitative differences, therefound some delays in molecular changes in the buffalo’s casein micelles.It showed that buffalo milk can be employed for the production of products which are alreadybeing produced by cow milk like different types of cheeses and to prepare casein constituents

Breastmilk donations: Bacteriological assessment, analysis of causes of non-compliance and suggestions for improvement

International audienceA total of 1099 breastmilk donations received by the milk bank at the Amiens University Hospital from January to June 2016 were assessed for bacteriological contamination according to French regulations. This consisted in enumerating the total aerobic flora before and after heat treatment as well as the specific enumeration of coagulase-positive staphylococci. Results above the mandatory limits for at least one of these parameters were found in 25.9% of the donations, resulting in the destruction of approximately one-quarter of the volume of the donations (similar to 195 L). This is a huge loss in both economic and health-related terms for neonates, especially for pre-terms. To identify ways to improve the bacteriological assessment results and reduce the percentage of discarded milk, an analysis of the causes was conducted. The two main causes of non-compliance were the detection of a cultivable aerobic flora after heat treatment and the presence of coagulase-positive staphylococci above the mandatory limit (11.7% and 11.2% of the tested donations, respectively). Bacillus spp. were the leading cause of post-heat treatment non-compliance. Therefore, the implementation of better environmental control could help reduce this kind of contamination. As for samples harboring coagulase-positive staphylococci, a further detection of toxins using molecular biology techniques could help discriminate actual health-hazardous donations that have to be destroyed while enabling the use of toxin-negative donations. Nevertheless, the economic viability of this proposal needs to be further assessed because these techniques are costly. Finally, a change in breastmilk dilutions used to enumerate the total aerobic flora to better reflect the actual level of these bacteria in the milk was proposed. Indeed, the comparison of various combinations of milk dilutions led to the conclusion that the association of the 1/10 and 1/100 dilutions was the best compromise between technical ease of enumeration and ensuring the safety of the donations. Implementing these suggestions would help reduce the rate of non-compliance and give better access to safe breastmilk donations for neonates. (C) 2018 Elsevier Masson SAS. All rights reserved

Biomimetic layer-by-layer templates for calcium phosphate biomineralization

International audienc

J Proteome Res

The neurodegenerative disorder Alzheimer’s disease (AD) is the most common cause of dementia in the elderly. The presence of neurofibrillary tangles, consisting of hyperphosphorylated tau protein, is one of the major neuropathologic characteristics of the disease, making this protein an attractive biomarker for AD and a possible target for therapy. Here, we describe an optimized immunoprecipitation mass spectrometry method that enables, for the first time, detailed characterization of tau in human cerebrospinal fluid. The identities of putative tau fragments were confirmed using nanoflow liquid chromatography and tandem mass spectrometry. Nineteen tryptic fragments of tau were detected, of which 16 are found in all tau isoforms while 3 represented unique tau isoforms. These results pave the way for clinical CSF studies on the tauopathies

Size variation of the non-recombining region on the mating-type chromosomes in the fungal Podospora anserina species complex

International audienceSex chromosomes often carry large non-recombining regions that can extend progressively over time, generating evolutionary strata of sequence divergence. However, some sex chromosomes display an incomplete suppression of recombination. Large genomic regions without recombination and evolutionary strata have also been documented around fungal mating-type loci, but have been studied in only a few fungal systems. In the model fungus Podospora anserina (Ascomycota, Sordariomycetes), the reference S strain lacks recombination across a 0.8 Mb region around the mating-type locus. The lack of recombination in this region ensures that nuclei of opposite mating types are packaged into a single ascospore (pseudo-homothallic lifecycle). We found evidence for a lack of recombination around the mating-type locus in the genomes of 10 P. anserina strains and six closely related pseudo-homothallic Podospora species. Importantly, the size of the non-recombining region differed between strains and species, as indicated by the heterozygosity levels around the mating-type locus and experimental selfing. The non-recombining region is probably labile and polymorphic, differing in size and precise location within and between species, resulting in occasional, but infrequent, recombination at a given base pair. This view is also supported by the low divergence between mating types, and the lack of strong linkage disequilibrium, chromosomal rearrangements, trans-specific polymorphism and genomic degeneration. We found a pattern suggestive of evolutionary strata in P. pseudocomata. The observed heterozygosity levels indicate low but non-null outcrossing rates in nature in these pseudo-homothallic fungi. This study adds to our understanding of mating-type chromosome evolution and its relationship to mating system