Self-similarity under inflation and level statistics: a study in two dimensions

Energy level spacing statistics are discussed for a two dimensional quasiperiodic tiling. The property of self-similarity under inflation is used to write a recursion relation for the level spacing distributions defined on square approximants to the perfect quasiperiodic structure. New distribution functions are defined and determined by a combination of numerical and analytical calculations.Comment: Latex, 13 pages including 6 EPS figures, paper submitted to PR

Linking solid-state phenomena via energy differences in `archetype crystal structures'

Categorization underlies understanding. Conceptualizing solid-state structures of organic molecules with `archetype crystal structures' bridges established categories of disorder, polymorphism and solid solutions and is herein extended to special position and high-Z′ structures. The concept was developed in the context of disorder modelling [Dittrich, B. (2021). IUCrJ, 8, 305–318] and relies on adding quantum chemical energy differences between disorder components to other criteria as an explanation as to why disorder – and disappearing disorder – occurs in an average structure. Part of the concept is that disorder, as probed by diffraction, affects entire molecules, rather than just the parts of a molecule with differing conformations, and the finding that an R·T energy difference between disorder archetypes is usually not exceeded. An illustrative example combining disorder and special positions is the crystal structure of oestradiol hemihydrate analysed here, where its space-group/subgroup relationship is required to explain its disorder of hydrogen-bonded hydrogen atoms. In addition, we show how high-Z′ structures can also be analysed energetically and understood via archetypes: high-Z′ structures occur when an energy gain from combining different rather than overall alike conformations in a crystal significantly exceeds R·T, and this finding is discussed in the context of earlier explanations in the literature. Twinning is not related to archetype structures since it involves macroscopic domains of the same crystal structure. Archetype crystal structures are distinguished from crystal structure prediction trial structures in that an experimental reference structure is required for them. Categorization into archetype structures also has practical relevance, leading to a new practice of disorder modelling in experimental least-squares refinement alluded to in the above-mentioned publication

Luminescence Properties of a Fibonacci Photonic Quasicrystal

We report the realization of an active one-dimensional Fibonacci photonic quasi-crystal via spin coating. Manipulation of the luminescence properties of an organic dye embedded in the quasi-crystal is presented and compared to theoretical simulations. The luminescence occurs via the pseudo-bandedge mode and follows the dispersion properties of the Fibonacci crystal. Time resolved luminescence measurement of the active structure shows faster spontaneous emission rate, indicating the effect of the large photon densities available at the bandedge due to the presence of critically localized states. The experimental results are in excellent agreement with the theoretical calculations.Comment: PDF file, 14 pages 4 figure

The definition of Endometriosis Expert Centres

Endometriosis is a common condition that causes pain and infertility. It can lead to absenteeism and also to multiple surgeries with a consequent risk of impaired fertility, and constitutes a major public health cost. Despite the existence of numerous national and international guidelines, the management of endometriosis remains suboptimal. To address this issue, the French College of Gynaecologists and Obstetricians (CNGOF) and the Society of Gynaecological and Pelvic Surgery (SCGP) convened a committee of experts tasked with defining the criteria for establishing a system of care networks, headed by Expert Centres, covering all of mainland France and its overseas territories. This document sets out the criteria for the designation of Expert Centres. It will serve as a guide for the authorities concerned, to ensure that the means are provided to adequately manage patients with endometriosis

Définition des centres experts en endométriose

OBJECTIVES: The Collège national des gynécologues obstétriciens français (CNGOF), in agreement with the Société de chirurgie gynécologique et pelvienne (SCGP), has set up a commission in 2017 to define endometriosis expert centres, with the aim of optimizing endometriosis care in France. METHODS: The committee included members from university and general hospitals as well as private facilities, representing medical, surgical and radiological aspects of endometriosis care. Opinion of endometriosis patients\u27 associations was obtained prior to writing this work. The final text was presented and unanimously validated by the members of the CNGOF Board of Directors at its meeting of October 13, 2017. RESULTS: Based on analysis of current management of endometriosis and the last ten years opportunities in France, the committee has been able to define the contours of endometriosis expert centres. The objectives, production specifications, mode of operation, missions and funding for these centres were described. The following missions have been specifically defined: territorial organization, global and referral care, communication and teaching as well as research and evaluation. CONCLUSION: Because of its daily impact for women and its economic burden in France, endometriosis justifies launching of expert centres throughout the country with formal accreditation by health authorities, ideally as part of the National Health Plan

Discovery and Optimization of DNA Gyrase and Topoisomerase IV Inhibitors with Potent Activity against Fluoroquinolone-Resistant Gram-Positive Bacteria

Herein, we describe the discovery and optimization of a novel series that inhibits bacterial DNA gyrase and topoisomerase IV via binding to, and stabilization of, DNA cleavage complexes. Optimization of this series led to the identification of compound 25, which has potent activity against Gram-positive bacteria, a favorable in vitro safety profile, and excellent in vivo pharmacokinetic properties. Compound 25 was found to be efficacious against fluoroquinolone-sensitive Staphylococcus aureus infection in a mouse thigh model at lower doses than moxifloxacin. An X-ray crystal structure of the ternary complex formed by topoisomerase IV from Klebsiella pneumoniae, compound 25, and cleaved DNA indicates that this compound does not engage in a water-metal ion bridge interaction and forms no direct contacts with residues in the quinolone resistance determining region (QRDR). This suggests a structural basis for the reduced impact of QRDR mutations on antibacterial activity of 25 compared to fluoroquinolones.</p

Prise en charge des endométriomes en France : enquête de pratiques

International audienceObjectivesTo present an overview of French practices for the management of endometriomas.MethodsWe carried out a nationwide survey of practices concerning the management of endometriomas between October 2021 and January 2022. This study was carried out by means of two questionnaires sent to surgical centers used to treat endometriosis (n = 62) and to Assisted Reproductive Technology (ART) centers (n = 102).ResultsAt the end of the survey, 39/62 (62.9%) surgical teams from the centers contacted had given a response and 51/102 (50.0%) from ART centers. Laparoscopic cystectomy was the technique most frequently used by almost two thirds of the surgical teams (61%) when there was no known infertility, whereas it was the most common technique for only 14% of the ART teams. On the contrary, ultrasound-guided sclerotherapy was the most frequent technique for more than half of the ART teams (56%) and for only 8% of the surgical teams. In case of recurrence, 49% of surgical teams would choose ultrasound-guided sclerotherapy. Prior to IVF, 73% of ARP teams stated that they ‘rarely’ treated endometriomas.ConclusionThe results of our study show a certain variability in practices between different centers and depending on the presence or absence of infertility for the management of endometriomas in France.ObjectifsPrésenter un état des lieux des pratiques françaises pour la prise en charge des endométriomes.MéthodesNous avons réalisé une enquête de pratiques, à l’échelle nationale, concernant la prise en charge des endométriomes entre octobre 2021 et janvier 2022. Cette étude a été réalisée par le biais de deux questionnaires adressés à des centres de chirurgie ayant l’habitude de prendre en charge l’endométriose (n = 62) ainsi que les centres d’assistance médicale à la procréation (AMP ; n = 102).RésultatsÀ l’issue de l’enquête, 39/62 (62,9 %) équipes chirurgicales des centres contactés avaient donné une réponse et 51/102 (50,0 %) pour les AMP. La kystectomie par cœlioscopie était la technique la plus fréquemment utilisée par près de deux tiers des équipes de chirurgie (61 %) lorsqu’il n’existait pas de contexte d’infertilité connue alors qu’il s’agit de la technique la plus courante pour seulement 14 % des équipes d’assistance médicale à la procréation (AMP). La sclérothérapie échoguidée était au contraire la technique la plus fréquente pour plus de la moitié des équipes d’AMP (56 %) et pour seulement 8 % des équipes de chirurgie. En cas de récidive, 49 % des équipes de chirurgie choisiraient la sclérothérapie échoguidée. Avant une fécondation in vitro (FIV), 73 % des équipes d’AMP déclaraient traiter « rarement » les endométriomes.ConclusionLes résultats de notre étude montrent une certaine variabilité dans les pratiques entre les différents centres et en fonction de la présence ou non d’une infertilité pour la prise en charge des endométriomes en France

Crystal Engineering: a step towards the understanding and rational investigations of polymorphism and drug substance properties

International audienc

Crystal Engineering: a step towards the understanding and rational investigations of polymorphism and drug substance properties

International audienc