Improvement of the performances of a commercial hand-held laser-induced breakdown spectroscopy instrument for steel analysis using multiple artificial neural networks.

In this article, we present a study on the optimization of the analytical performance of a commercial hand-held laser-induced breakdown spectroscopy instrument for steel analysis. We show how the performances of the instrument can be substantially improved using a non-linear calibration approach based on a set of Artificial Neural Networks (ANNs), one optimized for the determination of the major elements of the alloy, and the others specialized for the analysis of minor components. Tests of the instrument on steel samples used for instrument internal calibration demonstrate a comparable accuracy with the results of the ANNs, while the latter are considerably more accurate when unknown samples, not used for calibration/training, are tested.

Multi-scale laboratory routine in the efficacy assessment of conservative products for natural stones.

The evaluation of conservative treatments' efficacy on natural building stones are usually based on standard recommendation routines finalized to evaluate compatibility and harmfulness of products in turn of the substrate. However, the visualization and the quantification of products inside pore structure of natural stones is not immediate through standard tests, so that imaging and advanced techniques are recently proposed in material conservation field to improve knowledge on penetration depth, modification of pore-air interface at different scale and monitor dynamic absorption processes. Moreover, natural stones are usually characterized by complex structure, which changes due to conservative treatments have to be inspected at different scale (from micrometer to nanometer). In this prospective, the assessment of laboratory practices able to integrate multiscale methods and give back a complete overview on interaction between new conservative formulates and natural stones is of high interest. In this paper, we propose a methodological routine for efficacy assessment of conservative products, incorporating classical and innovative nondestructive techniques. Validation of the workflow has been verified on a high porous natural stone treated with new hybrid formulates appropriately customized for conservation issues. •The study intends to add new insights on problems related to consolidation of high porous carbonate stone, application methods in consolidating natural stones and methods to evaluate efficacy of new products.•A multi-scale laboratory investigation procedure is proposed by integrating standard and innovative nondestructive methods. Merits and limits of each applied method are discussed during validation.•The possibility to incorporate standard routines and/or substitute destructive testing with non-destructive ones seem to be a valid alternative to evaluate efficiency and monitor behavior of stones treated with consolidating products.

Selective pigment medium for Streptococcus agalactiae.

Increased awareness of the importance of Streptococcus agalactiae (Group B streptococcus) in neonatal morbidity and mortality has demonstrated the need for a selective and differential primary plating medium. In this report we describe a selective pigment medium containing colistin and nalidixic acid that allows presumptive identification of S. agalactiae from the primary plate, even when specimens are polymicrobic. A preliminary study compared the value of three media for pigment production by 137 known S. agalactiae strains. This was followed by a clinical laboratory trial using the best of these pigment media at an obstetric hospital in which 581 specimens from neonates, female reproductive tracts, and urinary tracts were screened. Subsequent to the clinical laboratory trial, an epidemiological investigation using the selective pigment medium was conducted on a mother/infant population. Of the 1,331 specimens screened for S. agalactiae, 75 (5.6%) were positive on 5% sheep blood agar and 79 (5.9%) were positive on the selective pigment medium.