Gas phase Elemental abundances in Molecular cloudS (GEMS) II. On the quest for the sulphur reservoir in molecular clouds: the H2S case.

CONTEXT: Sulphur is one of the most abundant elements in the Universe. Surprisingly, sulphuretted molecules are not as abundant as expected in the interstellar medium and the identity of the main sulphur reservoir is still an open question. AIMS: Our goal is to investigate the H2S chemistry in dark clouds, as this stable molecule is a potential sulphur reservoir. METHODS: Using millimeter observations of CS, SO, H2S, and their isotopologues, we determine the physical conditions and H2S abundances along the cores TMC 1-C, TMC 1-CP, and Barnard 1b. The gas-grain model Nautilus is used to model the sulphur chemistry and explore the impact of photo-desorption and chemical desorption on the H2S abundance. RESULTS: Our modeling shows that chemical desorption is the main source of gas-phase H2S in dark cores. The measured H2S abundance can only be fitted if we assume that the chemical desorption rate decreases by more than a factor of 10 when n H > 2 × 104. This change in the desorption rate is consistent with the formation of thick H2O and CO ice mantles on grain surfaces. The observed SO and H2S abundances are in good agreement with our predictions adopting an undepleted value of the sulphur abundance. However, the CS abundance is overestimated by a factor of 5 - 10. Along the three cores, atomic S is predicted to be the main sulphur reservoir. CONCLUSIONS: The gaseous H2S abundance is well reproduced, assuming undepleted sulphur abundance and chemical desorption as the main source of H2S. The behavior of the observed H2S abundance suggests a changing desorption efficiency, which would probe the snowline in these cold cores. Our model, however, highly overestimates the observed gas-phase CS abundance. Given the uncertainty in the sulphur chemistry, we can only conclude that our data are consistent with a cosmic elemental S abundance with an uncertainty of a factor of 10.

Gas phase Elemental abundances in Molecular cloudS (GEMS): I. The prototypical dark cloud TMC 1.

GEMS is an IRAM 30m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud TMC 1. Extensive millimeter observations have been carried out with the IRAM 30m telescope (3 mm and 2 mm) and the 40m Yebes telescope (1.3 cm and 7 mm) to determine the fractional abundances of CO, HCO+, HCN, CS, SO, HCS+, and N2H+ in three cuts which intersect the dense filament at the well-known positions TMC 1-CP, TMC 1-NH3, and TMC 1-C, covering a visual extinction range from A V ~ 3 to ~20 mag. Two phases with differentiated chemistry can be distinguished: i) the translucent envelope with molecular hydrogen densities of 1-5×103 cm-3; and ii) the dense phase, located at A V > 10 mag, with molecular hydrogen densities >104 cm-3. Observations and modeling show that the gas phase abundances of C and O progressively decrease along the C+/C/CO transition zone (A V ~ 3 mag) where C/H ~ 8×10-5 and C/O~0.8-1, until the beginning of the dense phase at A V ~ 10 mag. This is consistent with the grain temperatures being below the CO evaporation temperature in this region. In the case of sulfur, a strong depletion should occur before the translucent phase where we estimate a S/H ~ (0.4 - 2.2) ×10-6, an abundance ~7-40 times lower than the solar value. A second strong depletion must be present during the formation of the thick icy mantles to achieve the values of S/H measured in the dense cold cores (S/H ~8×10-8). Based on our chemical modeling, we constrain the value of ζ H2 to ~ (0.5 - 1.8) ×10-16 s-1 in the translucent cloud.

Toothbrushing training programme using an iPad® for children and adolescents with autism.

AIM: To improve the oral health of children and teenagers with autism spectrum disorder (ASD) by using an iPad®-based training programme. METHODS: Fifty-two children and teenagers with ASD (aged 3-19 years) educated in schools or in care centres participated in this cohort study and followed for 8 months. A training programme for teaching toothbrushing behaviours was proposed to the educational staff. Quotation grids enabled assessment of the programme's efficacy. RESULTS: Showed an improvement in toothbrushing. The children's autonomy increased and oral care was more easily implemented when steps were taken by the caregivers. Wilcoxon analysis showed significant improvement in each variable related to toothbrushing. CONCLUSIONS: The iPad® is an attractive and easy device for people with ASD to use. Its use in a training programme for teaching toothbrushing behaviours was efficient.

Training children with autism spectrum disorder to undergo oral assessment using a digital iPad® application.

AIM: To present a training programme for teaching children and adolescents with autism spectrum disorder (ASD), to be compliant with a dental examination. METHODS: Fifty-two children and adolescents with ASD (age range 3-19 years) with a parent-signed consent form were enrolled. Dental examinations were performed once a month in education centres by a paediatric dentist using a visual activity schedule on an iPad® that was created with a digital application, çATED. Achievement and anxiety were evaluated using scales and grids every 2 months for 8 months. RESULTS: Showed an improvement in oral assessment; the children became compliant and less anxious. The percentage of individuals who underwent the entire dental exam process increased over time; it was 25% at the beginning of the study and 65.4% after 8 months. Only 7.7% of the sample was not anxious at the beginning, while 59.6% of the sample was not anxious after 8 months. Wilcoxon analysis also showed significant improvement in the studied variables. CONCLUSIONS: Training children and adolescents with ASD to undergo dental examination was efficient. The use of the iPad® is attractive and easy for practitioners and people with ASD.

Prevalence of dental anomalies in French orthodontic patients: A retrospective study.

OBJECTIVES: To investigate the prevalence and gender distributions of dental anomalies in French orthodontic patients. MATERIAL AND METHODS: A retrospective review of the dental files of orthodontic patients was conducted to investigate the frequencies of dental anomalies. Pretreatment intraoral photographs and panoramic radiographs were analyzed. The occurrence rates of various dental anomalies (as determined by the numbers, shapes, structures, exfoliations, and eruptions of teeth) were calculated as percentages and differences in gender distribution using Chi2 and Fisher tests. RESULTS: Five hundred fifty-one patients receiving orthodontic treatment between 2003 and 2013 at a French hospital were included in the study: 45.74% of the patients (n=252) presented at least one dental anomaly. Taurodontism was the most common (15.06%), followed by ectopic eruption (11.43%). Odontoma, macrodontia, fusion, gemination, talon cusp, dentinogenesis imperfecta, regional odontodysplasia, premature tooth eruption, and premature exfoliation were not found. No statistically significant correlations were found between gender and the occurrence of dental anomalies. CONCLUSION: French orthodontic patients exhibit a high rate of dental anomalies, indicating that dental anomalies should be carefully considered in the orodental management of French patients.

[Integrating the touch-screen into oral health prevention programs for people with cognitive disabilities: An exploratory study in children]. / Intégration de la tablette tactile dans les programmes de prévention bucco-dentaire destinés aux personnes en situation de handicap cognitif : étude exploratoire chez l'enfant.

BACKGROUND: The oral diseases of people with disabilities are the same as those observed in the general population but occur earlier and more intensely. Primary prevention, especially toothbrushing, is at the forefront of the appropriate management of these patients. The aim of this study is to evaluate the use of a digital application on iPad® as mediator for learning toothbrushing in children with disabilities. METHODS: Twelve children from a care-center were included in this preliminary study. A training program for toothbrushing was conducted, using a visual activity schedule on iPad®. Quotation grids enabled to assess the initial situation and the program efficacy over an 11-month period. RESULTS: The children progressed over time in their autonomy and in their compliance during toothbrushing. Wilcoxon's analysis showed that these progresses were significant, although some steps remained more difficult to achieve. Three months after the end of the program, the children maintained their skills. CONCLUSIONS: The integration of the iPad® as a support for visual pedagogy and learning is useful in a dental context, for children with cognitive disabilities.

[Tools and techniques to improve the oral health of children with autism]. / Amélioration de la santé orale des enfants avec autisme : les outils à notre disposition.

Autism spectrum disorder (ASD) is a life-long heterogeneous psychiatric disorder, characterized by impaired social interaction and communication, and the presence of repetitive and stereotyped behaviors as well as restricted interests. These features have an impact on the oral health of these individuals: high risk of dental caries, poorer periodontal status, and bruxism are often described. Children with ASD often provide limited collaboration with medical procedures, particularly those considered invasive such as dental care. Children with ASD are prone to agitation, self-injury, and emotional dysregulation; they can also present hypersensitivity to sensory input. These features make it difficult for professionals to examine and treat children with ASD; they interfere with dental care and constitute a barrier to it. Most of them are treated under general anesthesia or sedation. Therefore, children with ASD present a challenge for the dental community. Adapted and specific strategies are required to allow individuals with ASD to go beyond the barriers of dental care. Different tools and techniques of evidence-based practice can be considered: visual pedagogy, behavioral approaches, and numeric devices can be used. Pediatricians have a key role in the oral care of children with autism. The aim of this article is to present the oral health associated with ASD, to set out the possible ways to improve oral health, to enable the practitioner to detect problems, to raise awareness, and to help patients and their families in their care pathway.

Deexcitation dynamics of superhydrogenated polycyclic aromatic hydrocarbon cations after soft-x-ray absorption.

We have investigated the response of superhydrogenated gas-phase coronene cations upon soft x-ray absorption. Carbon (1s)⟶π^{⋆} transitions were resonantly excited at hν=285 eV. The resulting core hole is then filled in an Auger decay process, with the excess energy being released in the form of an Auger electron. Predominantly highly excited dications are thus formed, which cool down by hydrogen emission. In superhydrogenated systems, the additional H atoms act as a buffer, quenching loss of native H atoms and molecular fragmentation. Dissociation and transition state energies for several H loss channels were computed by means of density functional theory. Using these energies as input into an Arrhenius-type cascade model, very good agreement with the experimental data is found. The results have important implications for the survival of polyaromatic hydrocarbons in the interstellar medium and reflect key aspects of graphene hydrogenation.

Distinct phenotype of PHF6 deletions in females.

We report on two female patients carrying small overlapping Xq26.2 deletions of 100 kb and 270 kb involving the PHF6 gene. Mutations in PHF6 have been reported in individuals with Borjeson-Forssman-Lehmann syndrome, a condition present almost exclusively in males. Two very recent papers revealed de novo PHF6 defects in seven female patients with intellectual disability and a phenotype resembling Coffin-Siris syndrome (sparse hair, bitemporal narrowing, arched eyebrows, synophrys, high nasal root, bulbous nasal tip, marked clinodactyly with the hypoplastic terminal phalanges of the fifth fingers and cutaneous syndactyly of the toes, Blaschkoid linear skin hyperpigmentation, dental anomalies and occasional major malformations). The clinical presentation of these patients overlaps completely with our first patient, who carries a germline deletion involving PHF6. The second patient has a mosaic deletion and presented with a very mild phenotype of PHF6 loss in females. Our report confirms that PHF6 loss in females results in a recognizable phenotype overlapping with Coffin-Siris syndrome and distinct from Borjeson-Forssman-Lehmann syndrome. We expand the clinical spectrum and provide the first summary of the recommended medical evaluation.

Quantum tunneling of oxygen atoms on very cold surfaces.

Any evolving system can change state via thermal mechanisms (hopping a barrier) or via quantum tunneling. Most of the time, efficient classical mechanisms dominate at high temperatures. This is why an increase of the temperature can initiate the chemistry. We present here an experimental investigation of O-atom diffusion and reactivity on water ice. We explore the 6-25 K temperature range at submonolayer surface coverages. We derive the diffusion temperature law and observe the transition from quantum to classical diffusion. Despite the high mass of O, quantum tunneling is efficient even at 6 K. As a consequence, the solid-state astrochemistry of cold regions should be reconsidered and should include the possibility of forming larger organic molecules than previously expected.

Culture medium modulates the behaviour of human dental pulp-derived cells: technical note.

In vitro approaches have extensively been developed to study reparative dentinogenesis. While dental pulp is a source of unidentified progenitors able to differentiate into odontoblast-like cells, we investigated the effect of two media; MEM (1.8 mM Ca and 1 mM Pi) and RPMI 1640 (0.8 mM Ca and 5 mM Pi) on the behaviour of human dental pulp cells. Our data indicate that MEM significantly increased cell proliferation and markedly enhanced the proportion of alpha-smooth muscle actin positive cells, which represent a putative source of progenitors able to give rise to odontoblast-like cells. In addition, MEM strongly stimulated alkaline phosphatase activity and was found to induce expression of transcripts encoding dentin sialophosphoprotein, an odontoblastic marker, without affecting that of parathyroid hormone/parathyroid hormone related protein-receptor and osteonectin. In conclusion, these observations demonstrate that not only proliferation but also differentiation into odontoblast-like cells was induced by rich calcium and poor phosphate medium (MEM) as compared to RPMI 1640. This study provides important data for the determination of the optimal culture conditions allowing odontoblast-like differentiation in human pulp cell culture.

Development of an odontoblast in vitro model to study dentin mineralization.

The aim of the present work was to characterize the odontoblastic proliferation, differentiation, and matrix mineralization in culture of the recently established M2H4 rat cell line. Proliferation was assessed by cell counts, differentiation by RT-PCR analysis, and mineralization by alizarin red staining, atomic absorption spectrometry, and FTIR microspectroscopy. The results showed that M2H4 cell behavior closely mimics in vivo odontoblast differentiation, with, in particular, temporally regulated expression of DMP-1 and DSPP. Moreover, the mineral phase formed by M2H4 cells was similar to that in dentin from rat incisors. Finally, because in mice, transforming growth factor (TGF)-beta1 over-expression in vivo leads to an hypomineralization similar to that observed in dentinogenesis imperfecta type II, effects of TGF-beta1 on mineralization in M2H4 cell culture were studied. Treatment with TGF-beta1 dramatically reduced mineralization, whereas positive control treatment with bone morphogenetic protein-4 enhanced it, suggesting that M2H4 cell line is a promising tool to explore the mineralization mechanisms in physiopathologic conditions.