140 research outputs found
Simulating Particle Dispersions in Nematic Liquid-Crystal Solvents
A new method is presented for mesoscopic simulations of particle dispersions
in nematic liquid crystal solvents. It allows efficient first-principle
simulations of the dispersions involving many particles with many-body
interactions mediated by the solvents. A simple demonstration is shown for the
aggregation process of a two dimentional dispersion.Comment: 5 pages, 5 figure
A Smooth Interface Method for Simulating Liquid Crystal Colloid Dispersions
A new method is presented for mesoscopic simulations of particle dispersions
in liquid crystal solvents. It allows efficient first-principle simulations of
the dispersions involving many particles with many-body interactions mediated
by the solvents. Demonstrations have been performed for the aggregation of
colloid dispersions in two-dimensional nematic and smectic-C* solvents
neglecting hydrodynamic effects, which will be taken into account in the near
future.Comment: 13 pages, 4 figure
Combined genetic approaches yield a 48% diagnostic rate in a large cohort of French hearing-impaired patients
International audienceHearing loss is the most common sensory disorder and because of its high genetic heterogeneity, implementation of Massively Parallel Sequencing (MPS) in diagnostic laboratories is greatly improving the possibilities of offering optimal care to patients. We present the results of a two-year period of molecular diagnosis that included 207 French families referred for non-syndromic hearing loss. Our multi-step strategy involved (i) DFNB1 locus analysis, (ii) MPS of 74 genes, and (iii) additional approaches including Copy Number Variations, in silico analyses, minigene studies coupled when appropriate with complete gene sequencing, and a specific assay for STRC. This comprehensive screening yielded an overall diagnostic rate of 48%, equally distributed between DFNB1 (24%) and the other genes (24%). Pathogenic genotypes were identified in 19 different genes, with a high prevalence of GJB2, STRC, MYO15A, OTOF, TMC1, MYO7A and USH2A. Involvement of an Usher gene was reported in 16% of the genotyped cohort. Four de novo variants were identified. This study highlights the need to develop several molecular approaches for efficient molecular diagnosis of hearing loss, as this is crucial for genetic counselling, audiological rehabilitation and the detection of syndromic forms
Assessing the effectiveness of the Ramsar Convention in preserving wintering waterbirds in the Mediterranean
lthough biological conservation is based on international agreements, its effectiveness depends on how countries implement such recommendations as effective conservation tools. The Ramsar Convention is the oldest international treaty for wetland and waterbird conservation, establishing the world's largest network of protected areas. However, since it does not constitute any binding measure, its effectiveness in protecting wintering waterbird populations at an international scale has been questioned. Here, we use long-term (1991–2012) count data to assess the effectiveness of the Ramsar Convention in the Mediterranean Basin. We compared abundance and temporal trends of 114 waterbird species between 251 Ramsar wetlands and 3486 non-Ramsar wetlands. We found that the Ramsar network is critical for wintering waterbirds, concentrating nearly half of all waterbirds counted in the Mediterranean Basin in only 7% of monitored wetlands. Waterbird trends followed a northwestsoutheast gradient, with a population decrease in the East. A significant and positive Ramsar effect on population trends was only found for the species of higher conservation concern in the Maghreb, particularly when a management plan was implemented. The Ramsar Convention was previously used on very important wetlands for waterbirds in Southern Europe, but is now an underused conservation tool. Our study suggests weaknesses in the use of Ramsar as an effective conservation tool in most of the Mediterranean Basin. However, the Ramsar Convention effectiveness to enhance waterbird populations in the Maghreb should encourage strengthening the Ramsar Convention. It should be done particularly in countries with limited environmental agreements and by systematic implementation of management plans. Conservation measures International conventions Protected areas Protection status Monitoring WetlandsacceptedVersio
Effective forces in colloidal mixtures: from depletion attraction to accumulation repulsion
Computer simulations and theory are used to systematically investigate how
the effective force between two big colloidal spheres in a sea of small spheres
depends on the basic (big-small and small-small) interactions. The latter are
modeled as hard-core pair potentials with a Yukawa tail which can be both
repulsive or attractive. For a repulsive small-small interaction, the effective
force follows the trends as predicted by a mapping onto an effective
non-additive hard-core mixture: both a depletion attraction and an accumulation
repulsion caused by small spheres adsorbing onto the big ones can be obtained
depending on the sign of the big-small interaction. For repulsive big-small
interactions, the effect of adding a small-small attraction also follows the
trends predicted by the mapping. But a more subtle ``repulsion through
attraction'' effect arises when both big-small and small-small attractions
occur: upon increasing the strength of the small-small interaction, the
effective potential becomes more repulsive. We have further tested several
theoretical methods against our computer simulations: The superposition
approximation works best for an added big-small repulsion, and breaks down for
a strong big-small attraction, while density functional theory is very accurate
for any big-small interaction when the small particles are pure hard-spheres.
The theoretical methods perform most poorly for small-small attractions.Comment: submitted to PRE; New version includes an important quantitative
correction to several of the simulations. The main conclusions remain
unchanged thoug
Pediatric cochlear implantation: an update
Deafness in pediatric age can adversely impact language acquisition as well as educational and social-emotional
development. Once diagnosed, hearing loss should be rehabilitated early; the goal is to provide the child with
maximum access to the acoustic features of speech within a listening range that is safe and comfortable. In presence
of severe to profound deafness, benefit from auditory amplification cannot be enough to allow a proper language
development. Cochlear implants are partially implantable electronic devices designed to provide profoundly deafened
patients with hearing sensitivity within the speech range. Since their introduction more than 30 years ago, cochlear
implants have improved their performance to the extent that are now considered to be standard of care in the
treatment of children with severe to profound deafness. Over the years patient candidacy has been expanded and
the criteria for implantation continue to evolve within the paediatric population. The minimum age for implantation
has progressively reduced; it has been recognized that implantation at a very early age (12–18 months) provides
children with the best outcomes, taking advantage of sensitive periods of auditory development. Bilateral implantation
offers a better sound localization, as well as a superior ability to understand speech in noisy environments than unilateral
cochlear implant. Deafened children with special clinical situations, including inner ear malformation, cochlear nerve
deficiency, cochlear ossification, and additional disabilities can be successfully treated, even thogh they require
an individualized candidacy evaluation and a complex post-implantation rehabilitation. Benefits from cochlear
implantation include not only better abilities to hear and to develop speech and language skills, but also improved
academic attainment, improved quality of life, and better employment status. Cochlear implants permit deaf people
to hear, but they have a long way to go before their performance being comparable to that of the intact human ear;
researchers are looking for more sophisticated speech processing strategies as well as a more efficient coupling
between the electrodes and the cochlear nerve with the goal of dramatically improving the quality of sound of
the next generation of implants
Value of hospital antimicrobial stewardship programs [ASPs]:a systematic review
Abstract Background Hospital antimicrobial stewardship programs (ASPs) aim to promote judicious use of antimicrobials to combat antimicrobial resistance. For ASPs to be developed, adopted, and implemented, an economic value assessment is essential. Few studies demonstrate the cost-effectiveness of ASPs. This systematic review aimed to evaluate the economic and clinical impact of ASPs. Methods An update to the Dik et al. systematic review (2000–2014) was conducted on EMBASE and Medline using PRISMA guidelines. The updated search was limited to primary research studies in English (30 September 2014–31 December 2017) that evaluated patient and/or economic outcomes after implementation of hospital ASPs including length of stay (LOS), antimicrobial use, and total (including operational and implementation) costs. Results One hundred forty-six studies meeting inclusion criteria were included. The majority of these studies were conducted within the last 5 years in North America (49%), Europe (25%), and Asia (14%), with few studies conducted in Africa (3%), South America (3%), and Australia (3%). Most studies were conducted in hospitals with 500–1000 beds and evaluated LOS and change in antibiotic expenditure, the majority of which showed a decrease in LOS (85%) and antibiotic expenditure (92%). The mean cost-savings varied by hospital size and region after implementation of ASPs. Average cost savings in US studies were 2.50 to $2640), with similar trends exhibited in European studies. The key driver of cost savings was from reduction in LOS. Savings were higher among hospitals with comprehensive ASPs which included therapy review and antibiotic restrictions. Conclusions Our data indicates that hospital ASPs have significant value with beneficial clinical and economic impacts. More robust published data is required in terms of implementation, LOS, and overall costs so that decision-makers can make a stronger case for investing in ASPs, considering competing priorities. Such data on ASPs in lower- and middle-income countries is limited and requires urgent attention
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