297 research outputs found

    Discrimination by Infrared Spectroscopy: Application to Micronized Locust Bean and Guar Gums

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    The authentication of locust bean and guar powder gums requires usually the use of sophisticated and time-consuming analytical techniques. There is a need for fast and simple analytical techniques for the objective of a quality control methodology. Commercial locust bean and guar micronized powder gums present characteristic MIR spectra. Principal component analysis of the infrared spectra of these micronized powder gums allowed to distinguish locust bean from guar samples and to perform good classification results. The prediction of the two varieties was done without any ambiguity with a partial least square regression-discriminant analysis (PLS-DA). A simplex approach was used to generate binary blends mathematically taking into account the intrinsic variability of chemical composition of commercial products. The simulated spectral profiles allowed to develop predictive model of the percentage of gums in blends

    Smartphone-Based Virtual Agents Can Help the General Population Concerned by Sleep Complaints: A Proof-of-Concept Study During COVID-19 Confinement

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    Background: The COVID-19 crisis induces psychosocial stress and sleep complaints that require early management. KANOPEE is a smartphone-based application, providing an interaction with a virtual agent dedicated to screen and deliver behavioral interventions to fight sleep disorders. This paper describes the feasibility study of this application, during the context of COVID-19 confinement in France. Method: 2,069 users of aged 18 years and over downloaded the app during the inclusion period (between 22 April and 5 May 2020). Users first answered a screening interview based on the insomnia severity index (ISI) that was conducted by the virtual agent. If participants were positive for insomniac complaints (ISI > 14), they could join a two-stage intervention program: a) complete an electronic sleep diary for one week, and b) follow personalized sleep recommendations for 10 days. Measures collected included socio-demographic information, ISI and sleep/wake schedules; and acceptance and trust of the agent.Bordeaux Region Aquitaine Initiative for NeurosciencePhénotypage humain et réalité virtuell

    J Med Internet Res

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    Background: The COVID-19 crisis and consequent confinement restrictions have caused significant psychosocial stress and reports of sleep complaints, which require early management, have increased during recent months. To help individuals concerned about their sleep, we developed a smartphone-based app called KANOPEE that allows users to interact with a virtual agent dedicated to autonomous screening and delivering digital behavioral interventions. Objective: Our objective was to assess the feasibility of this app, in terms of inclusion rate, follow-up rate, perceived trust and acceptance of the virtual agent, and effects of the intervention program, in the context of COVID-19 confinement in France. Methods: The virtual agent is an artificial intelligence program using decision tree architecture and interacting through natural body motion and natural voice. A total of 2069 users aged 18 years and above downloaded the free app during the study period (April 22 to May 5, 2020). These users first completed a screening interview based on the Insomnia Severity Index (ISI) conducted by the virtual agent. If the users were positive for insomnia complaints (ISI score >14), they were eligible to join the 2-stage intervention program: (1) complete an electronic sleep diary for 1 week and (2) follow personalized sleep recommendations for 10 days. We collected and analyzed the following measures: sociodemographic information, ISI scores and sleep/wake schedules, and acceptance and trust of the agent. Results: Approximately 76% (1574/2069) of the app users completed the screening interview with the virtual agent. The virtual agent was well accepted by 27.4% (431/1574) of the users who answered the acceptance and trust questionnaires on its usability, satisfaction, benevolence, and credibility. Of the 773 screened users who reported sleep complaints (ISI score >14), 166 (21.5%) followed Step 1 of the intervention, and only 47 of those (28.3%) followed Step 2. Users who completed Step 1 found that their insomnia complaints (baseline mean ISI score 18.56, mean ISI score after Step 1 15.99; P21) did not respond to either intervention. Conclusions: These preliminary results suggest that the KANOPEE app is a promising solution to screen populations for sleep complaints and that it provides acceptable and practical behavioral advice for individuals reporting moderately severe insomnia.Bordeaux Region Aquitaine Initiative for NeurosciencePhénotypage humain et réalité virtuell

    Effects of sodium nitrite reduction, removal or replacement on cured and cooked meat for microbiological growth, food safety, colon ecosystem, and colorectal carcinogenesis in Fischer 344 rats

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    Epidemiological and experimental evidence indicated that processed meat consumption is associated with colorectal cancer risks. Several studies suggest the involvement of nitrite or nitrate additives via N-nitroso-compound formation (NOCs). Compared to the reference level (120 mg/kg of ham), sodium nitrite removal and reduction (90 mg/kg) similarly decreased preneoplastic lesions in F344 rats, but only reduction had an inhibitory effect on Listeria monocytogenes growth comparable to that obtained using the reference nitrite level and an effective lipid peroxidation control. Among the three nitrite salt alternatives tested, none of them led to a significant gain when compared to the reference level: vegetable stock, due to nitrate presence, was very similar to this reference nitrite level, yeast extract induced a strong luminal peroxidation and no decrease in preneoplastic lesions in rats despite the absence of NOCs, and polyphenol rich extract induced the clearest downward trend on preneoplastic lesions in rats but the concomitant presence of nitrosyl iron in feces. Except the vegetable stock, other alternatives were less efficient than sodium nitrite in reducing L. monocytogenes growth

    WISE J072003.20-084651.2B Is A Massive T Dwarf

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    We present individual dynamical masses for the nearby M9.5+T5.5 binary WISE J072003.20-084651.2AB, a.k.a. Scholz's star. Combining high-precision CFHT/WIRCam photocenter astrometry and Keck adaptive optics resolved imaging, we measure the first high-quality parallactic distance (6.800.06+0.056.80_{-0.06}^{+0.05} pc) and orbit (8.060.25+0.248.06_{-0.25}^{+0.24} yr period) for this system composed of a low-mass star and brown dwarf. We find a moderately eccentric orbit (e=0.2400.010+0.009e = 0.240_{-0.010}^{+0.009}), incompatible with previous work based on less data, and dynamical masses of 99±699\pm6 MJupM_{\rm Jup} and 66±466\pm4 MJupM_{\rm Jup} for the two components. The primary mass is marginally inconsistent (2.1σ\sigma) with the empirical mass-magnitude-metallicity relation and models of main-sequence stars. The relatively high mass of the cold (Teff=1250±40T_{\rm eff} = 1250\pm40 K) brown dwarf companion indicates an age older than a few Gyr, in accord with age estimates for the primary star, and is consistent with our recent estimate of \approx70 MJupM_{\rm Jup} for the stellar/substellar boundary among the field population. Our improved parallax and proper motion, as well as an orbit-corrected system velocity, improve the accuracy of the system's close encounter with the solar system by an order of magnitude. WISE J0720-0846AB passed within 68.7±2.068.7\pm2.0 kAU of the Sun 80.5±0.780.5\pm0.7 kyr ago, passing through the outer Oort cloud where comets can have stable orbits.Comment: accepted to A

    Reappraisal of Vipera aspis Venom Neurotoxicity

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    BACKGROUND: The variation of venom composition with geography is an important aspect of intraspecific variability in the Vipera genus, although causes of this variability remain unclear. The diversity of snake venom is important both for our understanding of venomous snake evolution and for the preparation of relevant antivenoms to treat envenomations. A geographic intraspecific variation in snake venom composition was recently reported for Vipera aspis aspis venom in France. Since 1992, cases of human envenomation after Vipera aspis aspis bites in south-east France involving unexpected neurological signs were regularly reported. The presence of genes encoding PLA(2) neurotoxins in the Vaa snake genome led us to investigate any neurological symptom associated with snake bites in other regions of France and in neighboring countries. In parallel, we used several approaches to characterize the venom PLA(2) composition of the snakes captured in the same areas. [br/] METHODOLOGY/PRINCIPAL FINDINGS: We conducted an epidemiological survey of snake bites in various regions of France. In parallel, we carried out the analysis of the genes and the transcripts encoding venom PLA(2)s. We used SELDI technology to study the diversity of PLA(2) in various venom samples. Neurological signs (mainly cranial nerve disturbances) were reported after snake bites in three regions of France: Languedoc-Roussillon, Midi-Pyrénées and Provence-Alpes-Côte d'Azur. Genomes of Vipera aspis snakes from south-east France were shown to contain ammodytoxin isoforms never described in the genome of Vipera aspis from other French regions. Surprisingly, transcripts encoding venom neurotoxic PLA(2)s were found in snakes of Massif Central region. Accordingly, SELDI analysis of PLA(2) venom composition confirmed the existence of population of neurotoxic Vipera aspis snakes in the west part of the Massif Central mountains. [br/] CONCLUSIONS/SIGNIFICANCE: The association of epidemiological studies to genetic, biochemical and immunochemical analyses of snake venoms allowed a good evaluation of the potential neurotoxicity of snake bites. A correlation was found between the expression of neurological symptoms in humans and the intensity of the cross-reaction of venoms with anti-ammodytoxin antibodies, which is correlated with the level of neurotoxin (vaspin and/or ammodytoxin) expression in the venom. The origin of the two recently identified neurotoxic snake populations is discussed according to venom PLA(2) genome and transcriptome data
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