Chemical compounds and toxicological assessments of drinking water stored in polyethylene terephthalate (PET) bottles: A source of controversy reviewed

A declaration of conformity according to European regulation No. 10/2011 is required to ensure the safety of plastic materials in contact with foodstuffs. This regulation established a positive list of substances that are authorized for use in plastic materials. Some compounds are subject to restrictions and/or specifications according to their toxicological data. Despite this, the analysis of PET reveals some non-intentionally added substances (NIAS) produced by authorized initial reactants and additives.Genotoxic and estrogenic activities in PET-bottled water have been reported. Chemical mixtures in bottled water have been suggested as the source of these toxicological effects. Furthermore, sample preparation techniques, such as solid-phase extraction (SPE), to extract estrogen-like compounds in bottled water are controversial. It has been suggested that inappropriate extraction methods and sample treatment may result in false-negative or positive responses when testing water extracts in bioassays. There is therefore a need to combine chemical analysis with bioassays to carry out hazard assessments.Formaldehyde, acetaldehyde and antimony are clearly related to migration from PET into water. However, several studies have shown other theoretically unexpected substances in bottled water. The origin of these compounds has not been clearly established (PET container, cap-sealing resins, background contamination, water processing steps, NIAS, recycled PET, etc.).Here, we surveyed toxicological studies on PET-bottled water and chemical compounds that may be present therein. Our literature review shows that contradictory results for PET-bottled water have been reported, and differences can be explained by the wide variety of analytical methods, bioassays and exposure conditions employed.     

Gut Microbiome Analysis for Personalized Nutrition: The State of Science

Whereas most concepts of personalized nutrition (PN) in the past, included genotyping, recent years have brought new approaches that include microbiome analysis to optimize recommendations for diet and lifestyle changes. The new approach, offered by companies, that microbiome analysis provides a real benefit to either more concise recommendations or for increased compliance to PN, is largely lacking scientific validation. Although the microbiome field shows enormous proliferation, it has some major flaws that make its use in the public health domain currently critical. Starting with the quality and representative character of the stool samples, its processing and analysis as well as assembly of metagenome data and the interpretation. Moreover, there is still no consensus of what constitutes a “normal/healthy” microbiome, nor what features characterize a dysbiotic microbiome. And, based on hundreds of individual parameters and environmental factors, the intestinal microbiome shows a huge variability and consequently changing one factor—such as food intake—is likely to have a limited impact in achieving optimized health. The present review intends to summarize the state of consolidated knowledge on human gut microbiome in the context of diet and disease, its key features, and its influencing factors as well as its “add-on” quality for PN offers.     

Modelling of initial fatigue crack growth and crack branching under fretting conditions

Crack propagation during Stage I, in terms of crack initiation sites and growth directions and crack branching mechanisms under fretting conditions, is investigated using both experimental and theoretical approaches. Fretting tests were conducted on an aeronautical aluminium alloy. Two crack types are observed during Stage I corresponding, respectively, to specific mode I and II conditions. Transition from Stage I to Stage II is characterized for both crack types by a crack branching towards a new propagation direction of ≈65° to the specimen surface. Specific parameters linked to mode I and II propagation driving forces are proposed. Crack location and initial growth directions during Stage I are predicted in accordance with these parameters, and are in very good agreement with experimental observations. The conditions governing the transition from Stage I to Stage II are then identified. It is shown that under fretting conditions, cracks branch along a new direction, thereby maximizing the crack-opening amplitude.     

Transient nucleate boiling under stepwise heat generation for highly wetting fluids

Experiments of transient nucleate boiling are carried out on highly wetting fluids from two metallic specimen, a thick flat sample and a wire. The initial condition is controlled in terms of the system temperature as well as by a primary activation of the nucleation sites. A stepwise heat generation is investigated and the role of thermal inertia is clarified. The thermal behaviour of the system and the associated time scales are found to depend on temperature at boiling inception. This one is similar to the steady-state value for the thick flat sample but depends on the magnitude of the heating step in the case of the thin wire.     

Transient natural convection and conjugate transients around a line heat source

Transient natural convection in liquid nitrogen around a heated wire is studied experimentally and numerically. A thin bronze wire of 40 μm in diameter and 5.1 cm in length heated by Joule effect is used in experiments and time evolutions of the wire temperature are measured through its electrical resistance. Numerical simulations of such flows are performed by using velocity-pressure formulation, spectral methods and domain decomposition technique. Experimental data and numerical results are compared and show that although the wire is extremely thin its thermal inertia plays an important role during early transients.Scaling analyses performed for the convection set-up and transients yield t∼q^−1/2 and ΔT∼q^3/4, which are confirmed by numerical simulations.For wires heated by Joule effect hybrid thermal conditions--combined Dirichlet and Neumann conditions are proposed on the wire surface and validated by numerical simulations. On the other hand flow conditions to be imposed on the outer artificial boundary are not well known and the answer to the question remains still open: two types of flow conditions are tested and yield different velocity fields.     

Cognitive-Behavioral Therapy for Insomnia: Comparison of Individual Therapy, Group Therapy, and Telephone Consultations.

Forty-five adults with primary insomnia received cognitive-behavioral therapy (CBT) implemented in a group therapy format, in individual face-to-face therapy or through brief individual telephone consultations. The results indicate that CBT was effective in improving sleep parameters with all 3 methods of treatment implementation, and there was no significant difference across methods of implementation. All 3 treatment modalities produced improvements in sleep that were maintained for 6 months after treatment completion. These results suggest that group therapy and telephone consultations represent cost-effective alternatives to individual therapy for the management of insomnia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fatigue following traumatic brain injury: Frequency, characteristics, and associated factors.

Objectives: To document the frequency, characteristics, and factors associated with fatigue following traumatic brain injury (TBI). Design: Survey methodology and multivariate statistical design. Setting: Rehabilitation center and community. Participants: 452 participants aged 16 years and over with minor to severe TBI who answered a questionnaire measuring diverse aspects of fatigue as well as different dimensions of psychological distress, pain, and sleep quality. Measures: Proportion of participants reporting being significantly fatigued. Validated measures of fatigue, sleep quality, and psychological distress. Results of a logistic regression analysis. Results: Significant fatigue was reported by 68.5% of participants. Mental fatigue was the most prominent type of fatigue, followed by physical fatigue. Fatigue was present even several years following the accident and had many perceived impacts on day-to-day function. Factors associated with fatigue were a shorter time since injury; being on long-term disability leave; and higher levels of sleep problems, cognitive disturbances, and anxiety. Conclusion: Fatigue is a prevalent problem after TBI that requires more clinical and scientific attention because it probably has important repercussions on the quality of rehabilitation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do milking practices influence the bacterial diversity of raw milk?

The link between milk production practices and bacterial diversity of 67 raw milks from dairy farms in the Savoie and Haute-Savoie regions of France was studied by Single Strand Conformation Polymorphism (SSCP) analysis. The milking practices and the cleanliness of different parts of the cow housing were evaluated. The SSCP bacterial profiles allow to classify the 67 milks into three groups: group A was characterised by a majority of Gram-positive non-lactic acid bacteria (Corynebacterineae and Micrococcaceae) and a high level of hygiene in milking practices. The SSCP profiles of groups B and C were close but different from those of group A: they were both dominated by lactic acid bacteria and by a less intensive hygiene practices. The group B milks were characterised by the dominance of Gram-negative bacteria and Lactococcus lactis species while those of group C were dominated by Brevibacterium linens and Leuconostoc mesenteroides. The variation of balance between bacterial populations can be associated with differences in hygienic milking production practices.