A new high-pressure technique for the measurement of low frequency seismic attenuation using cyclic torsional loading.

We report a new technique for torsional testing of materials under giga-pascal pressures, which uses a shearing module in a large-volume Paris-Edinburgh press in combination with high-resolution fast radiographic x-ray imaging. The measurement of the relative amplitude and phase lag between the cyclic displacement in the sample and a standard material (Al2O3) provides the effective shear modulus and attenuation factor for the sample. The system can operate in the 0.001-0.01 Hz frequency range and up to 5 GPa and 2000 K although high-temperature measurements may be affected by grain growth and plastic strain. Preliminary experimental results on San Carlos olivine are in quantitative agreement with previously reported Q-1 factors at lower pressure. This cyclic torsional loading method opens new directions to quantify the viscoelastic properties of minerals/rocks at seismic frequencies and under pressure-temperature conditions relevant to the Earth's mantle for a better interpretation of seismological data.

Microelectromechanical Transducer to Monitor High-Doses of Nuclear Irradiation.

This paper reports the design, fabrication and measured performance of a passive microelectromechanical transducer for the wireless monitoring of high irradiation doses in nuclear environments. The sensing device is composed of a polymer material (high-density polyethylene) sealed inside a cavity. Subjected to ionizing radiation, this material releases various gases, which increases the pressure inside the cavity and deflects a dielectric membrane. From the measurement of the deflection, the variation of the applied pressure can be estimated, and, in turn, the dose may be determined. The microelectromechanical structure can also be used to study and validate the radiolysis properties of the polymer through its gas emission yield factor. Measurement of the dielectric membrane deflection is performed here to validate on the one hand the required airtightness of the cavity exposed to doses about 4 MGy and on the other hand, the functionality of the fabricated dosimeter for doses up to 80 kGy. The selection of appropriate materials for the microelectromechanical device is discussed, and the outgassing properties of the selected high-density polyethylene are analysed. Moreover, the technological fabrication process of the transducer is detailed.

Acoustofluidic rotational tweezing enables high-speed contactless morphological phenotyping of zebrafish larvae.

Modern biomedical research and preclinical pharmaceutical development rely heavily on the phenotyping of small vertebrate models for various diseases prior to human testing. In this article, we demonstrate an acoustofluidic rotational tweezing platform that enables contactless, high-speed, 3D multispectral imaging and digital reconstruction of zebrafish larvae for quantitative phenotypic analysis. The acoustic-induced polarized vortex streaming achieves contactless and rapid (~1 s/rotation) rotation of zebrafish larvae. This enables multispectral imaging of the zebrafish body and internal organs from different viewing perspectives. Moreover, we develop a 3D reconstruction pipeline that yields accurate 3D models based on the multi-view images for quantitative evaluation of basic morphological characteristics and advanced combinations of metrics. With its contactless nature and advantages in speed and automation, our acoustofluidic rotational tweezing system has the potential to be a valuable asset in numerous fields, especially for developmental biology, small molecule screening in biochemistry, and pre-clinical drug development in pharmacology.

Loss-of-function mutations in MRAP2 are pathogenic in hyperphagic obesity with hyperglycemia and hypertension.

The G-protein-coupled receptor accessory protein MRAP2 is implicated in energy control in rodents, notably via the melanocortin-4 receptor1. Although some MRAP2 mutations have been described in people with obesity1-3, their functional consequences on adiposity remain elusive. Using large-scale sequencing of MRAP2 in 9,418 people, we identified 23 rare heterozygous variants associated with increased obesity risk in both adults and children. Functional assessment of each variant shows that loss-of-function MRAP2 variants are pathogenic for monogenic hyperphagic obesity, hyperglycemia and hypertension. This contrasts with other monogenic forms of obesity characterized by excessive hunger, including melanocortin-4 receptor deficiency, that present with low blood pressure and normal glucose tolerance4. The pleiotropic metabolic effect of loss-of-function mutations in MRAP2 might be due to the failure of different MRAP2-regulated G-protein-coupled receptors in various tissues including pancreatic islets.

Contactless, programmable acoustofluidic manipulation of objects on water.

Contact-free manipulation of small objects (e.g., cells, tissues, and droplets) using acoustic waves eliminates physical contact with structures and undesired surface adsorption. Pioneering acoustic-based, contact-free manipulation techniques (e.g., acoustic levitation) enable programmable manipulation but are limited by evaporation, bulky transducers, and inefficient acoustic coupling in air. Herein, we report an acoustofluidic mechanism for the contactless manipulation of small objects on water. A hollow-square-shaped interdigital transducer (IDT) is fabricated on lithium niobate (LiNbO3), immersed in water and used as a sound source to generate acoustic waves and as a micropump to pump fluid in the ±x and ±y orthogonal directions. As a result, objects which float adjacent to the excited IDT can be pushed unidirectionally (horizontally) in ±x and ±y following the directed acoustic wave propagation. A fluidic processor was developed by patterning IDT units in a 6-by-6 array. We demonstrate contactless, programmable manipulation on water of oil droplets and zebrafish larvae. This acoustofluidic-based manipulation opens avenues for the contactless, programmable processing of materials and small biosamples.

Polyketide Synthase Plays a Conserved Role in Otolith Formation.

Otoliths (ear stones) are biomineralized complexes essential for the balancing and hearing function of the inner ears in fish. Their formation is controlled by a genetically programmed biological process that is yet to be defined. We have isolated and characterized a spontaneous genetic mutant zebrafish with a complete absence of otoliths, named no otolith 1 (not1). not1 mutants are unable to develop otoliths during embryonic stages and fail to respond to acoustic stimuli, indicating an inner ear defect. We identified a deleterious mutation (G239R) that altered a highly conserved amino acid residue in the zebrafish ortholog of type I polyketide synthase (pks1) to underlie these phenotypes and showed that expression of the polyketide synthase gene of Japanese medaka fish could rescue the otolith deficiency in not1 mutant zebrafish. Our finding highlights a critical and conserved role of type I polyketide synthase in the initiation of otolith formation. Given the functional homology between otoliths in teleost fish and otoconia in mammals and humans, not1 mutants provide a new animal model for the study of human otoconia-related diseases.

In-Situ Wireless Pressure Measurement Using Zero-Power Packaged Microwave Sensors.

This paper reports the indoor wireless measurement of pressure from zero-power (or passive) microwave (24 GHz) sensors. The sensors are packaged and allow the remote measurement of overpressure up to 2.1 bars. Their design, fabrication process and packaging are detailed. From the measurement of sensor scattering parameters, the outstanding sensitivity of 995 MHz/bar between 0.8 and 2.1 bars was achieved with the full-scale measurement range of 1.33 GHz. Moreover, the 3D radar imagery technique was applied for the remote interrogation of these sensors in electromagnetic reverberant environments. The full-scale dynamic range of 4.9 dB and the sensitivity of 4.9 dB/bar between 0.7 and 1.7 bars were achieved with radar detection in a highly reflective environment. These measurement results demonstrate for the first time the ability of the radar imagery technique to interrogate fully passive pressure sensors in electromagnetic reverberant environments.

A novel NEUROG3 mutation in neonatal diabetes associated with a neuro-intestinal syndrome.

Neonatal diabetes mellitus (NDM) is a rare form of non-autoimmune diabetes usually diagnosed in the first 6 months of life. Various genetic defects have been shown to cause NDM with diverse clinical presentations and variable severity. Among transcriptional factor genes associated with isolated or syndromic NDM, a few cases of homozygous mutations in the NEUROG3 gene have been reported, all mutated patients presenting with congenital malabsorptive diarrhea with or without diabetes at a variable age of onset from early life to childhood. Through a targeted next-generation sequencing assay for monogenic diabetes genes, we aimed to search for pathogenic deleterious mutation in a Turkish patient with NDM, severe malabsorptive diarrhea, neurointestinal dysplasia and other atypical features. In this patient, we identified a novel homozygous nonsense mutation (p.Q4*) in NEUROG3. The same biallelic mutation was found in another affected family member. Of note, the study proband presents with abnormalities of the intrahepatic biliary tract, thyroid gland and central nervous system, which has never been reported before in NEUROG3 mutation carriers. Our findings extend the usually described clinical features associated with NEUROG3 deficiency in humans, and question the extent to which a complete lack of NEUROG3 expression may affect pancreas endocrine function in humans.

[Orthodontics and Alexis Schange in 1841]. / L'orthodontie d'Alexis Schange en 1841.

INTRODUCTION: Alexis Schange was one of the first practitioners able to use accurate casts of the dental arches thanks to the invention of the impression-tray by Delabarre. Consequently, his diagnoses were more precise and his appliances fitted better than those of his predecessors. MATERIALS AND METHOD: The author will first outline the status of Orthodontics prior to Schange and the advent of the first casts, before describing Schange's contribution to Orthodontics. DISCUSSION: In 1841, Schange published his "Handbook of Dental Uprighting", a clear and pedagogical work and undoubtedly the best over the many years when Orthodontics was exclusively European.

[Optimization of the final lingual occlusion: an analysis]. / Optimisation de l'occlusion statique linguale terminale : une analyse.

INTRODUCTION: The objectives of orthodontic treatment are to achieve a functional, aesthetic and sustainable occlusion. However, its analysis is often limited to the study of its buccal side, easy to check in mouth. Yet, the lingual occlusion is also of paramount importance. MATERIAL AND METHOD: After calling to mind the ideal static objectives of treatment, described by some authors and defined by some scientific societies, this article studies the different supports for the analysis of lingual static occlusion and proposes a new protocol for the carving of orthodontic casts. RESULTS: The lingual occlusion end-of-treatment objectives lack details, whether by the scientific societies or literature, although we possess simple ways to study them. DISCUSSION: The lingual part of occlusion is rarely studied in our daily practice, particularly because its analysis cannot be achieved by a direct intraoral examination. However, it is of major importance in the success and stability of our treatments.

A truncating mutation in CEP55 is the likely cause of MARCH, a novel syndrome affecting neuronal mitosis.

BACKGROUND: Hydranencephaly is a congenital anomaly leading to replacement of the cerebral hemispheres with a fluid-filled cyst. The goals of this work are to describe a novel autosomal-recessive syndrome that includes hydranencephaly (multinucleated neurons, anhydramnios, renal dysplasia, cerebellar hypoplasia and hydranencephaly (MARCH)); to identify its genetic cause(s) and to provide functional insight into pathomechanism. METHODS: We used homozygosity mapping and exome sequencing to identify recessive mutations in a single family with three affected fetuses. Immunohistochemistry, RT-PCR and imaging in cell lines, and zebrafish models, were used to explore the function of the gene and the effect of the mutation. RESULTS: We identified a homozygous nonsense mutation in CEP55 segregating with MARCH. Testing the effect of this allele on patient-derived cells indicated both a reduction of the overall CEP55 message and the production of a message that likely gives rise to a truncated protein. Suppression or ablation of cep55l in zebrafish embryos recapitulated key features of MARCH, most notably renal dysplasia, cerebellar hypoplasia and craniofacial abnormalities. These phenotypes could be rescued by full-length but not truncated human CEP55 message. Finally, we expressed the truncated form of CEP55 in human cells, where we observed a failure of truncated protein to localise to the midbody, leading to abscission failure and multinucleated daughter cells. CONCLUSIONS: CEP55 loss of function mutations likely underlie MARCH, a novel multiple congenital anomaly syndrome. This association expands the involvement of centrosomal proteins in human genetic disorders by highlighting a role in midbody function.

[The birth of Edgewise or the last and best Angle's mechanisms]. / La naissance de l'Edgewise ou le dernier et le meilleur mécanisme d'Angle.

INTRODUCTION: Mechanical forces applied to the teeth constitute a not-insignificant feature of orthodontic treatment. Edgewise, the most commonly used type of mechanics, was introduced 88 years ago and has become a standard worldwide. The invention of Edgewise by E.H. Angle in 1928 is an event in the history of orthodontics which deserves to be recalled. MATERIALS AND METHODS: Starting with the initial search for this method and leading up to a presentation of the technique itself, this paper provides an overview of the history of Angle mechanics. RESULTS: In order to demonstrate the first mechanical system to function in the three planes of space, Angle provided precise diagrams and instructions for use while insisting, on several occasions, that his mechanics was not complicated and that careful study should allow users to overcome any potential difficulties. DISCUSSION: The mechanism as devised by Angle, who died shortly after launching his invention, was only used for a short length of time. However, all subsequently invented therapeutic techniques incorporated the mechanical principles underpinning Edgewise, paying tribute in this way to a great invention.

What Is the Best NGS Enrichment Method for the Molecular Diagnosis of Monogenic Diabetes and Obesity?

Molecular diagnosis of monogenic diabetes and obesity is of paramount importance for both the patient and society, as it can result in personalized medicine associated with a better life and it eventually saves health care spending. Genetic clinical laboratories are currently switching from Sanger sequencing to next-generation sequencing (NGS) approaches but choosing the optimal protocols is not easy. Here, we compared the sequencing coverage of 43 genes involved in monogenic forms of diabetes and obesity, and variant detection rates, resulting from four enrichment methods based on the sonication of DNA (Agilent SureSelect, RainDance technologies), or using enzymes for DNA fragmentation (Illumina Nextera, Agilent HaloPlex). We analyzed coding exons and untranslated regions of the 43 genes involved in monogenic diabetes and obesity. We found that none of the methods achieves yet full sequencing of the gene targets. Nonetheless, the RainDance, SureSelect and HaloPlex enrichment methods led to the best sequencing coverage of the targets; while the Nextera method resulted in the poorest sequencing coverage. Although the sequencing coverage was high, we unexpectedly found that the HaloPlex method missed 20% of variants detected by the three other methods and Nextera missed 10%. The question of which NGS technique for genetic diagnosis yields the highest diagnosis rate is frequently discussed in the literature and the response is still unclear. Here, we showed that the RainDance enrichment method as well as SureSelect, which are both based on the sonication of DNA, resulted in a good sequencing quality and variant detection, while the use of enzymes to fragment DNA (HaloPlex or Nextera) might not be the best strategy to get an accurate sequencing.

[The prehistory of orthodontics]. / La préhistoire de l'orthodontie.

Orthodontics came into being in 1728. Previously, practitioners were at a loss when confronted with crooked teeth. A Latin philosopher had an ingenious flash of orthodontic inspiration. Other authors were content to either extract the malposed teeth or to modify their shape. However, interest in an approach to preventive orthodontics had now begun.

Genetic variants in LEP, LEPR, and MC4R explain 30% of severe obesity in children from a consanguineous population.

OBJECTIVE: Single gene mutations leading to severe obesity have so far been identified in 3-5% cases in European populations. However, prevalence of these pathogenic mutations has not systematically been examined in specific consanguineous populations. Here we describe the incidence of obesity-associated mutations through a step-wise sequence analysis, in a cohort of 73 Pakistani children with severe obesity from consanguineous families. METHODS: Initially, all subjects were screened for mutations in coding regions of leptin (LEP) and melanocortin 4 receptor (MC4R) genes by direct sequencing. Subjects negative for mutation in these genes were screened using microdroplet PCR enrichment and NGS. Genomic structural variation was assessed by genotyping. Serum leptin, insulin, and cortisol were determined by ELISA. RESULTS: Among 73 children with severe obesity (BMI SDS > 3.0), we identified 22 probands and 5 relatives, carrying 10 different loss-of-function homozygous mutations in LEP, leptin receptor (LEPR), and MC4R genes, including 4 novel variants. Hypercortisolemia was significantly emphasized in LEP mutation carriers. CONCLUSIONS: The prevalence of pathogenic mutations in genes known to directly influence leptin-melanocortin signaling is 30% in our cohort. The results of this study emphasize the desirability of undertaking systematic and in-depth genetic analysis of cases with severe obesity in specific consanguineous populations.

[What makes a pleasing face]. / Pourquoi un visage plaît.

Regular faces are beautiful because they are expressive and arouse an interest in the observer due to the variations in their shape, their surface appearance and their movements. The sensitivity of the eye of the beholder is correlated to the expressivity of the face and of the dentition. Better, however, to avoid any indication of aggression that could foreshadow the senescence of the face.

Novel LEPR mutations in obese Pakistani children identified by PCR-based enrichment and next generation sequencing.

OBJECTIVE: Mutations in leptin receptor gene (LEPR) result in early onset extreme adiposity. However, their prevalence in different populations is not known. Indeed, LEPR screening by gold standard Sanger sequencing has been limited by its large size and the cost. One-step PCR-based targeted enrichment could be an option for rapid and cost effective molecular diagnosis of monogenic forms of obesity. METHODS: The study is based on 39 unrelated severely obese Pakistani children, previously shown to be negative for leptin (LEP) and melanocortin 4 receptor (MC4R) gene mutations, from an initial cohort of 62 probands. Patient samples were analyzed by microdroplet PCR-enrichment (RainDance technologies) targeting coding exons of 26 obesity-associated genes combined with next generation sequencing. Hormone levels were analyzed by ELISA. RESULTS: The analysis revealed two novel homozygous LEPR mutations, an essential splice site mutation in exon 15 (c.2396-1 G>T), and a nonsense mutation in exon 10 (c.1675 G>A). Both probands had high leptin levels and were phenotypically indistinguishable from age-matched leptin-deficient subjects from the same population. CONCLUSIONS: The two subjects carrying homozygous LEPR mutations, reported here for the first time in the Pakistani population, constitute 3% of the whole cohort of severely obese children (compared to 17% for LEP and 3% for MC4R).

Highly sensitive diagnosis of 43 monogenic forms of diabetes or obesity through one-step PCR-based enrichment in combination with next-generation sequencing.

OBJECTIVE: Accurate etiological diagnosis of monogenic forms of diabetes and obesity is useful as it can lead to marked improvements in patient care and genetic counseling. Currently, molecular diagnosis based on Sanger sequencing is restricted to only a few genes, as this technology is expensive, time-consuming, and labor-intensive. High-throughput next-generation sequencing (NGS) provides an opportunity to develop innovative cost-efficient methods for sensitive diabetes and obesity multigene screening. RESEARCH DESIGN AND METHODS: We assessed a new method based on PCR enrichment in microdroplets (RainDance Technologies) and NGS using the Illumina HiSeq2000 for the molecular diagnosis of 43 forms of monogenic diabetes or obesity. Forty patients carrying a known causal mutation for those subtypes according to diagnostic laboratories were blindly reanalyzed. RESULTS: Except for one variant, we reidentified all causal mutations in each patient associated with an almost-perfect sequencing of the targets (mean of 98.6%). We failed to call one highly complex indel, although we identified a dramatic drop of coverage at this locus. In three patients, we detected other mutations with a putatively deleterious effect in addition to those reported by the genetic diagnostic laboratories. CONCLUSIONS: Our NGS approach provides an efficient means of highly sensitive screening for mutations in genes associated with monogenic forms of diabetes and obesity. As cost and time to deliver results have been key barriers to uncovering a molecular cause in the many undiagnosed cases likely to exist, the present methodology should be considered in patients displaying features of monogenic diabetes or obesity.