On the use of carbon nanotubes as reinforcing fillers for elastomeric materials

Rubber composites containing multiwall carbon nanotubes are investigated. The results are compared with those obtained with conventional carbon black. In each case, the level of reinforcement is assessed from the mechanical and equilibrium swelling behavior. The state of dispersion is evaluated from transmission electron and atomic force microscopy methods. Copyright © 2006 Society of Chemical Industry     

On subtypes of developmental dyslexia: Evidence from processing time and accuracy scores.

Determined the proportion of phonological dyslexics (Ph-DYS) and surface dyslexics (S-DYS) in a population of French dyslexics by applying A. Castles and M. Coltheart's (1993) regression method to 2 diagnostic measures: pseudo-word and irregular-word processing time. 31 dyslexics were matched to 19 average readers of the same age (aged 10 yrs, CA controls) and to 19 younger children of the same reading level (aged 8 yrs, RL controls). Compared to CA controls, there were more Ph-DYS than S-DYS. Compared to RL controls, there were still a high number of Ph-DYS. The reliability of these subtypes across different measures of phonological and orthographic skills was also examined. Compared to RL controls, both groups of dyslexics were found to be impaired only in phonological skills. The moment at which the 2 dissociated profiles emerged in the course of cognitive development was assessed by examining data that was collected when the children were 7 and 8 yrs old. The results show that only the S-DYS's orthographic deficit increased with development. The authors also looked at whether the Ph-DYS and S-DYS profiles were associated with other specific cognitive deficits. Specific deficits in phonemic awareness and in phonological short-term memory were found for both Ph-DYS and S-DYS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Screening and confirmatory methods for the determination of melamine in cow’s milk and milk-based powdered infant formula: Validation and proficiency-tests of ELISA,HPLC-UV,GC-MS and LC-MS/MS

In recent years, two adulteration incidents concerning the addition of melamine, a small polar compound which is very rich in nitrogen, to pet food and infant formula products have occurred in China. These issues prompted private as well as governmental laboratories to develop methods for the analysis of melamine and related compounds in a wide variety of food products and ingredients. The development of methods was focussed on both, screening and quantification purposes, ranging from highly sophisticated chromatographic-mass spectrometric techniques to immuno-selective assays. The present work describes two screening and two confirmatory methods dedicated to the determination of melamine in cow’s milk and milk-based powdered infant formula. Screening methods are enzyme-linked immunosorbent assay (ELISA) and liquid chromatography coupled to ultraviolet detection, while confirmatory methods are based on gas and liquid chromatography coupled mass spectrometry techniques. Performance and validation data of the four methods, and results obtained in the frame of internal and European proficiency-tests are shown.     

Diversity of lactic acid bacteria isolated from AOC Salers cheese

The objective of this work was to describe the diversity of lactic acid bacteria in traditional raw milk Salers cheeses at the species and strain levels. The characterization of 381 strains isolated during ripening and various strain collections was investigated using physiological analysis and molecular techniques: Rep-PCR, species and genus specific amplifications and the sequence analysis of 16S rDNA for strain typing and taxonomic identification. The strains belonged to Lactobacillus plantarum, Lactobacillus paracasei, Lactococcus lactis, Lactococcus garviae, Enterococcus faecalis, Enterococcus faecium, Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, Streptococcus salivarius, Streptococcus millieri, Streptococcus macedonicus and Pediococcus pentosaceus. A wide phenotypic and genomic heterogeneity was observed within the different species (Lactobacillus plantarum, Lactobacillus paracasei and Leuconostoc mesenteroides) according to the origin and the time of ripening. The natural microflora was different from strain collection and each method must be combined to identify and characterize natural microflora. This study revealed the low selectivity of selective media used for the isolation of different groups of lactic acid bacteria except the Facultatively Heterofermentative lactobacilli medium selecting mesophile lactobacilli and SB medium selective for Enterococcus. The study reveals, for the first time, the microbial lactic acid bacteria community of Salers cheese and its diversity. A better knowledge of microbial flora will be useful to improve understanding of sensory quality of cheeses.     

A survey on performance management of operating rooms and a new KPI proposal

Performance management of operating rooms is of great importance in hospital management. From the patients' point of view, operating room capacity management ensures available capacity when needed and thus ensuring short (er) waiting time. From the hospital point of view, efficiently and effectively managing these expensive resources is a major concern. Because there are too many performance indicators with a lack of standardization on definitions and there is no one-size-fit-all metric that can assess the overall performance, how to measure is still a challenging question. This paper starts with describing the operating room's characteristics and presents a systematic literature survey exploring different sources for information on operating room performance management. The literature is screened for lists of performance indicators currently used by managers. Aside from the nature of indicators, the way these indicators are used is also investigated. The literature ends with the suggestion of a new key performance indicator (overall operating room effectiveness [OORE]) that is intended to be used in measuring the overall performance of operating rooms from a lean thinking perspective. To increase the ability of finding root causes of low performance, a delay categorization framework is also proposed. Implementation of the KPI is illustrated using a real-world data. In the conclusion, all the elements studied are brought together, and recommendations for research and practice are formulated.     

Cellulose nanocrystal‐based poly(butylene adipate‐co‐terephthalate) nanocomposites covered with antimicrobial silver thin films

In this study, we reported the preparation and prospective application of the nanocomposites of poly(butylene adipate‐co‐terephthalate) (PBAT) reinforced with cellulose nanocrystals (CNCs). CNCs were isolated from bleached sugarcane bagasse by acid hydrolysis and functionalized with adipic acid. Nanocomposites were prepared with different concentration of CNCs (0.8, 1.5, and 2.3 wt% CNC) by solution‐casting method and then were covered with silver thin film by magnetron sputtering. The results showed that the surface modification increased the degree of crystallinity of nanocrystals from 51% to 56%, decreasing their length and diameter. Moreover, AFM‐IR spectroscopy revealed that the modified CNCs were covered by adipic acid molecules, improving the dispersion of nanocrystals in PBAT. Well‐dispersed modified CNCs acted as heterogeneous nuclei for crystallization of PBAT, and increased the storage modulus of the polymer by more than 200%. These improvements in thermal and mechanical properties of CNC‐based PBAT associated with the decrease of 56% in the Escherichia coli biofilm formation on nanocomposites (antibacterial properties) qualify the CNC/PBAT nanocomposites covered with silver thin films to be used as food packaging. POLYM. ENG. SCI., 59:E356–E365, 2019. © 2019 Society of Plastics Engineers     

Structure et proprietes magnetiques de la perovskite Ba2TaCoO6

A new oxide Ba₂TaCoO₆ has been prepared. The crystallographic properties are determined, this compound is of the perovskite type, its space group is Pm3m and the parameter a = 4.077 A°. The variation of the magnetic susceptibility suggests the appearance of cobalt in the low spin state (Co^III) between 4 and 125 K.     

The Reinforcement of Elastomeric Networks by Fillers

Summary: The mechanisms involved in rubber reinforcement are discussed. A better molecular understanding of these mechanisms can be obtained by combining characterization of the mechanical behavior with an analysis of the chain segmental orientation accompanying deformation. While the strain dependence of the stress is the most common quantity used to assess the effect of filler addition, experimental determination of segmental orientation can be used to quantify the interfacial interactions between the elastomeric matrix and the mineral inclusions.

SEM micrograph of natural rubber containing 10 wt.‐% of organomodified clay.