Luminescence modulation in liquid crystalline phases containing a dispiro[fluorene-9,11′-indeno[1,2-b]fluorene-12′,9′′-fluorene] core

International audienceA luminescent liquid crystalline compound containing a bulky dispiro[fluorene-9,11′-indeno[1,2-b]fluorene-12′,9′′-fluorene] has been designed and synthesized by di-substitution of a bromo derivative with N-(4-ethynylphenyl)-3,4,5-tris(hexadecyloxy)benzamide fragments. This di-substituted 3π-2spiro derivative forms stable and well-organized mesophases over large temperature ranges. Combination of DSC, POM and SAXS analyses has revealed the formation of a lamellar mesophase between 60 and 150 °C followed by another mesophase with a 2-dimensional lattice of rectangular symmetry that remains up to the isotropization point near 225 °C. In the original molecular packing model deduced from SAXS, the tert-butyl terminal groups fill the centre of hollow columns constituted by both the dihydro(1,2-b)indenofluorene and benzamide fragments and separated from each other by the surrounding aliphatic tails. The merging of the columns yielding the lamellar phase turned out to be governed by the dynamics of both, the micro-phase segregation process and the network of hydrogen bonds. In the various mesomorphic states and in solution, a strong luminescence was observed. The emission spectrum however depends on temperature and drastically changes between both mesophases and the isotropic liquid. In particular, a strong modulation of the emission wavelength occurs at the isotropic to 2D phase transition. This luminescence modulation results from an enhanced contribution of the vibronic peaks at higher energies in the emission profile. The compound was also found to be soluble in 5CB and was integrated in a guest-host LC cell, allowing efficient modulation of the photoluminescence polarization, in the presence or absence of an electrical field

First case of NDM-1 producing Klebsiella pneumoniae in Caribbean islands

Characterize a NDM-1 producing K. pneumoniae isolate recovered from a patient hospitalized in Guadeloupe, French West Indies, after its transfer from CubaMethodsAntibiotic susceptibilities were determined by the disk diffusion method, and E-test. Carbapenemase production was assessed using the Carba NP test. Antibiotic resistance determinants and their surrounding structures were characterized by PCR mapping and DNA sequencing. Transfer of the β-lactam resistance marker was attempted by liquid mating-out assaysResultsHere we reported the first NDM-1 producing enterobacterial isolate recovered from Caribbean islands. This K. pneumoniae isolate belongs to a new sequence type (ST1649). The blaNDM-1 gene together with the aacA4 gene were carried on a self conjugative IncR plasmid of c.a. 80 kb.ConclusionThis study describes the first identification of a NDM-1 producer in Caribbean islands. The uncommon incompatibility group of the blaNDM-1 carrying plasmid and the uncommon ST type of the K. pneumoniae strain suggest a possible local emergence of NDM producers

2-Substituted vs 4-substituted-9,9′-spirobifluorene host materials for green and blue phosphorescent OLEDs: a structure-property relationship study

Nanotek for organic synthesis, and organic synthesis for nanotekInternational audienceWe report a structure-property relationship study of four 9,9′-spirobifluorene (SBF) derivatives (4-5Pm-SBF, 2-5Pm-SBF, 4-Ph-SBF and 2-Ph-SBF), substituted with either phenyl or pyrimidine at the \C2\ or \C4\ position of the \SBF\ core. Structural, thermal, electrochemical and photophysical properties have been examined and correlated to theoretical calculations in order to study the influence of the nature and the position of the substituent. The emission properties of 4- versus 2-substituted \SBFs\ are noticeably different highlighting, in the excited state, the remarkable effect of substitution in ortho position of SBF. All compounds have been used as host material for green dopant in PhOLEDs with very high performances (2-5Pm-SBF: CE>58 cd/A, PE>35 lm/W, EQE>14%). More importantly, the two 4-substituted \SBFs\ have been used as host materials in blue PhOLEDs, displaying high performance and a decrease of \VTH\ for 4-5Pm-SBF due to the incorporation of the electron-withdrawing pyrimidine

Epidemiology and outcome predictors in 450 patients with hanging-induced cardiac arrest: a retrospective study

BackgroundCardiac arrest is the most life-threatening complication of attempted suicide by hanging. However, data are scarce on its characteristics and outcome predictors.MethodsThis retrospective observational multicentre study in 31 hospitals included consecutive adults admitted after cardiac arrest induced by suicidal hanging. Factors associated with in-hospital mortality were identified by multivariate logistic regression with multiple imputations for missing data and adjusted to the temporal trends over the study period.ResultsOf 450 patients (350 men, median age, 43 [34–52] years), 305 (68%) had a psychiatric history, and 31 (6.9%) attempted hanging while hospitalized. The median time from unhanging to cardiopulmonary resuscitation was 0 [0–5] min, and the median time to return of spontaneous circulation (ROSC) was 20 [10–30] min. Seventy-nine (18%) patients survived to hospital discharge. Three variables were independently associated with higher in-hospital mortality: time from collapse or unhanging to ROSC>20 min (odds ratio [OR], 4.71; 95% confidence intervals [95%CIs], 2.02–10.96; p = 0.0004); glycaemia >1.4 g/L at admission (OR, 6.38; 95%CI, 2.60–15.66; p < 0.0001); and lactate >3.5 mmol/L at admission (OR, 6.08; 95%CI, 1.71–21.06; p = 0.005). A Glasgow Coma Scale (GCS) score of >5 at admission was associated with lower in-hospital mortality (OR, 0.009; 95%CI, 0.02–0.37; p = 0.0009).ConclusionIn patients with hanging-induced cardiac arrest, time from collapse or unhanging to return of spontaneous circulation, glycaemia, arterial lactate, and coma depth at admission were independently associated with survival to hospital discharge. Knowledge of these risk factors may help guide treatment decisions in these patients at high risk of hospital mortality

Thermal contact calibration between a thermocouple probe and a microhotplate

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Pyrolysis and gasification of solid waste and its components in a lab scale induction-heating reactor

International audienceThe present study investigates the thermochemical conversion of solid recovered fuel, represented by selected “model materials”. A laboratory-scale induction heated device was specifically developed to achieve gasification conditions close to those encountered in a fluidized bed reactor. The novel device can handle up to 5 grams of solid, allowing fast heating rates (near 70°C/s) and a homogeneous distribution of temperature all along the reactor. Pyrolysis tests of a SRF sample and four model materials (Polyethylene (PE), Polyethylene Terephthalate (PET), beech wood, cardboard) were performed at 800°C. The yield and composition of the produced gas for each sample were determinated. Experimental results will help to elucidate the relation between the initial components of waste derived fuels and the obtained reaction products

First evaluation of bendiocarb in experimental huts using different substrates in Madagascar

International audienceBACKGROUND:Indoor residual spraying with insecticide is recommended for malaria control in high-transmission settings. Determination of residual activity of insecticides is essential for the selection of appropriate indoor spraying policy. The present study was undertaken to evaluate the residual effect of bendiocarb, a carbamate insecticide used in Madagascar, on different indoor surfaces in order to elaborate future vector control interventions.METHODS:The residual activity of bendiocarb was evaluated in both experimental huts and houses. Tests in experimental huts on different substrates represented a small scale-field trials. The houses IRS performed in parallel of experimental huts IRS, was done to compare semi-field results and field results. Bioassays according to the World Health Organization (WHO) standard protocol were carried out on different substrates impregnated with bendiocarb using susceptible strains of Anopheles arabiensis and Aedes albopictus.RESULTS:Bendiocarb induced significantly high mortality in treated huts against exposed mosquito (p < 0.005) compared to untreated huts. The mortality is up to the WHO threshold of 80 % during 5 months post-treatment. Using a multivariate analysis, Ae. albopictus mortality decreased significantly from the 3rd month post-treatment. However, An. arabiensis mortality decreased significantly from the 4th month after treatment. Comparing mosquito mortality results from the mud experimental huts and the mud houses showed no significant difference regarding the persistence of bendiocarb on wall.CONCLUSIONS:Current data suggest variable persistence of bendiocarb according to the type of wall surfaces, highlighting the importance of testing insecticide for IRS in local context before using them in large scale. Data from this study validate also the importance of using experimental huts as representative tool to evaluate the effectiveness of an insecticide

Friction Modeling of a High-Precision Positioning System

Friction modeling of a high-precision positioning system using linear permanent magnet synchronous motors is investigated. The friction force is measured precisely by some specific experiments to eliminate the parasitic ripple force. The experimental data show that the relation between the lubrication force and the velocity is not linear as it is assumed in the conventional friction models used in automatic control. A new model for the lubrication force based on tribological observations is proposed and introduced to the LuGre friction model. The new model can characterize the lubrication force saturation which is encountered in the acquired data. The parameters of the new friction model are identified and compared with the standard ones

Pyrolysis of centimetre-scale wood particles: New experimental developments and results

International audienceThis work is devoted to the pyrolysis of centimetre-scale wood particles, for temperature ranging between 450 and 1050 degrees C. A specific device has been designed to perform pyrolysis tests on a single particle and to collect both thermal and chemical data which are necessary to describe pyrolysis at centimetre-scale. Temperature profiles inside the sample are monitored during pyrolysis. Char, gas, tars and water yields, as well as the elemental composition of each class of products are measured. The yields of the main gaseous species (CO, CO2, CH4, C2H4 and H-2) are monitored during the reaction. Tars are collected, and six compounds are quantified

Biomass Gasification Between 800 and 1,400 degrees C in the Presence of O-2: Drop Tube Reactor Experiments and Simulation

International audienceBeech sawdust particle conversion in a drop tube furnace was studied between 800 and 1,400 degrees C. Particular attention was paid to the influence of temperature and to the presence of oxygen on the gasification process. As temperature increases, light hydrocarbon production decreases and the CO + H-2 production (gas of interest for biofuel production) increases. Presence of oxygen in the gasification atmosphere allows consuming a high part of light hydrocarbons and enhancing carbon conversion into gas. However, high yields of CO2 and H2O were observed and the total yield of CO + H-2 was lower than in pyrolysis conditions