Elasto–optical behavior model of a step-index fiber under localized pressure

The intensity attenuation of a step-index optical fiber under localized pressure is investigated using the elasto–optical theory and the principles of geometrical optics. A model with a Gaussian variation of the refractive index in the axial direction is used to evaluate the effect of applied pressure on the external coating of the fiber. The results are compared with experimental measurements obtained using a prototype of an optical fiber pressure sensor.     

Mercury and lead sorption properties of poly(ethyleneimine) coated onto silica gel

In this article, we studied the sorption properties of poly(ethyleneimine) coated on silica gel for metal ions with impact on the environment, such as Zn(II), Cd(II), Hg(II), and Pb(II). The experiments were carried out by batch procedure and the effects of pH, concentration, and temperature were evaluated. In addition, the selectivity was studied for binary, ternary, and quaternary metal ion mixtures. Mercury and lead showed promising results, achieving higher than 65% of sorption after only 1 h of contact. Under competitive conditions, resin presented high selectivity toward Hg(II) reaching 91 and 87% of retention respect to total amount of ions for binary and quaternary mixtures, respectively. The effect of time on Pb(II) and Hg(II) sorption was studied by batch procedure and the experimental data were adjusted to pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. Pseudo-second-order model presented good agreement for Pb(II) sorption, while pseudo-first-order model fits better to Hg(II) sorption. Intra-particle diffusion model showed that sorption process is controlled mainly by film diffusion.     

Conjunctival impression cytology evaluation of patients with dry eye disease using scleral contact lenses

Purpose

To evaluate conjunctival impression cytology and HLADR expression changes after wearing scleral contact lenses (ScCLs) for moderate to severe dry eye disease (DED).

Human Milk Banking: Influence of Different Pasteurization Temperatures on Levels of Protein Sulfur Amino Acids and Some Free Amino Acids

Human milk is frequently heat‐treated in hospitals, particularly milk that is banked, to destroy contaminating bacteria and viruses, but this treatment simultaneously reduces the content of some vitamins, enzymes, and immunological and nutritional factors. This study was performed to find the optimal conditions for heat treatment. The effects of 2 pasteurization temperatures on levels of protein sulfur amino acids (methionine, cystine) and some free amino acids (taurine, glutamine, glutamic acid) in light of the oxidative instability that occurs especially during thermal treatment were examined. These substances in raw human milk and in milk treated at 56.5 °C and 62.5 °C for 30 min were compared. Samples of mature human milk from all feeds over 24 h were obtained from 13 healthy well‐nourished mothers of term infants. Each sample was divided into 3 parts: raw, treated at 56.5 °C for 30 min, treated at 62.5 °C for 30 min. The results showed that the availability of sulfur amino acids and free taurine is the same after heat treatment, whereas milk processing increased positively the levels of free glutamic acid and glutamine, but there is significance only for glutamine. The mean quantities of considered amino acids were similar in milk treated at the recommended pasteurization temperature (30 min at 62.5 °C) and at 56.5 ° for 30 min.     

Explosive Detection by Microthermal Analysis

Differential scanning microcalorimetry at high heating rates of ～ 300°C/s was performed on 30- to 100-µm-size explosive particles using two MEMS-based thermal conductivity gauges in air and under N₂. The gauges consist of a thin-film Si₃N_x membrane with a centrally located Al thin-film heater, which is surrounded by six thin-film Si/Al junctions, creating a temperature-sensitive thermopile (～ 1.3 mV/K) with an effective sensitive area of ca. 200 × 200 µm. Heating was carried out by applying a linear voltage ramp during 1.6 s. The measurements were performed in a specially designed exposure chamber having a transparent glass lid that enabled optical observation of the thermal process.

Besides explosives (TNT, RDX, picric acid, urea nitrate, and TATP) we have studied nonexplosive materials, organic and inorganic, in order to see whether the explosives have a unique response. The materials we studied were oxygen-poor and -rich organic compounds (polyethylene and sugars, respectively), sea sand, and iron flakes.

Clear, well-resolved exotherms were obtained at moderated temperatures (～ 250°C) for all types of explosive materials tested by us. In addition, all explosives exhibited a melting endotherm preceding the exotherm. Sea sand and iron showed no peaks at the heating temperature range. Polyethylene showed an endotherm representing its melting. The sugars showed an endotherm but also an exotherm when heated to elevated temperatures (> 370°C). The thermogram of each material depends on its properties and is characterized by a unique pattern. This pattern may enable the detection and identification of explosive particles using this technology.     

Qualification of the neutronic efficiency of erbium at zero burnup

The main asset of erbium as an alternative burnable poison to gadolinium is that it has a much lower thermal absorption efficient cross section that contributes to giving it much slower consumption kinetics than gadolinium, and also helps to generate much lower perturbation in the power distribution. The calculations performed with the APOLLO code and its associated library must be qualified and validated with an experiment in order to obtain a sufficient degree of confidence to envisage an industrial application of this poison. For this purpose the MIRTE UOX and MOX experiments were performed in the critical reactor EOLE at Cadarache within the framework of the EROÏNE programme. These experiments concern the neutronic assessment of a (U,Er)O₂ rod in a representative core of a pressurised water reactor lattice with an enhanced moderation ratio. The purpose of this paper is to show that the APOLLO2 code associated with its APOLLIB CEA 93 library is perfectly qualified at time zero to calculate erbium reactivity worth.     

Synthesis of water-soluble polymers containing sulfonic acid and amine moieties for the recovery of metal ions using ultrafiltration

Copolymers from 2-acrylamido-2-methyl-propane sulfonic acid (APSA) and N-acryloyl-N-methyl piperazine (AP) were synthesized by radical polymerization with ammonium peroxydisulfate as the initiator. The copolymerization yield ranged between 93 and 95%. The copolymers were completely water soluble, and were characterized by FTIR and NMR spectroscopy. The copolymer composition was determined from elemental analysis through the S/C ratio. The binding capacity for metal ion was studied by the LPR technique at different pH and filtration factors. The retention depended strongly on the pH and on the copolymer composition. With increasing pH and increasing content of APSA units in the copolymer, the metal ion retention increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 22–30, 2001     

The Predictive Role of Plasma Biomarkers in the Evolution of Aortopathies Associated with Congenital Heart Malformations

Dilatation of the aorta is a constantly evolving condition that can lead to the ultimate life-threatening event, acute aortic dissection. Recent research has tried to identify quantifiable biomarkers, with both diagnostic and prognostic roles in different aortopathies. Most studies have focused on the bicuspid aortic valve, the most frequent congenital heart disease (CHD), and majorly evolved around matrix metalloproteinases (MMPs). Other candidate biomarkers, such as asymmetric dimethylarginine, soluble receptor for advanced glycation end-products or transforming growth factor beta have also gained a lot of attention recently. Most of the aortic anomalies and dilatation-related studies have reported expression variation of tissular biomarkers. The ultimate goal remains, though, the identification of biomarkers among the serum plasma, with the upregulation of circulating MMP-1, MMP-2, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), asymmetric dimethylarginine (ADMA), soluble receptor for advanced glycation end-products (sRAGE) and transforming growth factor beta (TGF-β) being reported in association to several aortopathies and related complications in recent research. These molecules are apparently quantifiable from the early ages and have been linked to several CHDs and hereditary aortopathies. Pediatric data on the matter is still limited, and further studies are warranted to elucidate the role of plasmatic biomarkers in the long term follow-up of potentially evolving congenital aortopathies.     

Proteomics and Extracellular Vesicles as Novel Biomarker Sources in Peritoneal Dialysis in Children

Peritoneal dialysis (PD) represents the dialysis modality of choice for pediatric patients with end-stage kidney disease. Indeed, compared with hemodialysis (HD), it offers many advantages, including more flexibility, reduction of the risk of hospital-acquired infections, preservation of residual kidney function, and a better quality of life. However, despite these positive aspects, PD may be associated with several long-term complications that may impair both patient’s general health and PD adequacy. In this view, chronic inflammation, caused by different factors, has a detrimental impact on the structure and function of the peritoneal membrane, leading to sclerosis and consequent PD failure both in adults and children. Although several studies investigated the complex pathogenic pathways underlying peritoneal membrane alterations, these processes remain still to explore. Understanding these mechanisms may provide novel approaches to improve the clinical outcome of pediatric PD patients through the identification of subjects at high risk of complications and the implementation of personalized interventions. In this review, we discuss the main experimental and clinical experiences exploring the potentiality of the proteomic analysis of peritoneal fluids and extracellular vesicles as a source of novel biomarkers in pediatric peritoneal dialysis.