134 research outputs found

    Lock-in detection using a cryogenic low noise looped current preamplifier for the readout of resistive bolometers

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    We implemented a low noise current preamplifier for the readout of resistive bolometers. We tested the apparatus on thermometer resistances ranging from 10 Ohm to 500 Mohm. The use of current preamplifier overcomes constraints introduced by the readout time constant due to the thermometer resistance and the input capacitance. Using cold JFETs, this preamplifier board is shown to have very low noise: the Johnson noise of the source resistor (1 fA/Hz1/2) dominated in our noise measurements. We also implemented a lock-in chain using this preamplifier. Because of fast risetime, compensation of the phase shift may be unnecessary. If implemented, no tuning is necessary when the sensor impedance changes. Transients are very short, and thus low-passing or sampling of the signal is simplified. In case of spurious noise, the modulation frequency can be chosen in a much wider frequency range, without requiring a new calibration of the apparatus.Comment: 18 pages, 7 figures, Accepted in NIM

    Intercomparison of Permittivity Measurement Techniques for Ferroelectric Thin Layers

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    International audienceThe dielectric properties of a KTa0.65Nb0.35O3 (KTN) ferroelectric composition for a submicronic thin layer were measured in the microwave domain using different electromagnetic characterization methods. Complementary experimental techniques (broadband methods versus resonant techniques, waveguide versus transmission line) and complementary data processing procedures (quasi-static theoretical approaches versus full-wave analysis) were selected to investigate the best way to characterize ferroelectric thin films. The measured data obtained from the cylindrical resonant cavity method, the experimental method that showed the least sources of uncertainty, were taken as reference values for comparisons with results obtained using broadband techniques. The error analysis on the methods used is discussed with regard to the respective domains of validity for each method; this enabled us to identify the best experimental approach for obtaining an accurate determination of the microwave dielectric properties of ferroelectric thin layers

    Expression of a Dominant Negative CELF Protein In Vivo Leads to Altered Muscle Organization, Fiber Size, and Subtype

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    CUG-BP and ETR-3-like factor (CELF) proteins regulate tissue- and developmental stage-specific alternative splicing in striated muscle. We previously demonstrated that heart muscle-specific expression of a nuclear dominant negative CELF protein in transgenic mice (MHC-CELFΔ) effectively disrupts endogenous CELF activity in the heart in vivo, resulting in impaired cardiac function. In this study, transgenic mice that express the dominant negative protein under a skeletal muscle-specific promoter (Myo-CELFΔ) were generated to investigate the role of CELF-mediated alternative splicing programs in normal skeletal muscle.Myo-CELFΔ mice exhibit modest changes in CELF-mediated alternative splicing in skeletal muscle, accompanied by a reduction of endomysial and perimysial spaces, an increase in fiber size variability, and an increase in slow twitch muscle fibers. Weight gain and mean body weight, total number of muscle fibers, and overall muscle strength were not affected.Although these findings demonstrate that CELF activity contributes to the normal alternative splicing of a subset of muscle transcripts in vivo, the mildness of the effects in Myo-CELFΔ muscles compared to those in MHC-CELFΔ hearts suggests CELF activity may be less determinative for alternative splicing in skeletal muscle than in heart muscle. Nonetheless, even these small changes in CELF-mediated splicing regulation were sufficient to alter muscle organization and muscle fiber properties affected in myotonic dystrophy. This lends further evidence to the hypothesis that dysregulation of CELF-mediated alternative splicing programs may be responsible for the disruption of these properties during muscle pathogenesis

    Overlap and Mutual Distinctions between Clinical Recovery and Personal Recovery in People with Schizophrenia in a One-Year Study

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    Recovery is a multidimensional construct that can be defined either from a clinical perspective or from a consumer-focused one, as a self-broadening process aimed at living a meaningful life beyond mental illness. We aimed to longitudinally examine the overlap and mutual distinctions between clinical and personal recovery. Of 1239 people with schizophrenia consecutively recruited from the FondaMental Advanced Centers of Expertise for SZ network, the 507 present at one-year did not differ from those lost to follow-up. Clinical recovery was defined as the combination of clinical remission and functional remission. Personal recovery was defined as being in the rebuilding or in the growth stage of the Stages of Recovery Instrument (STORI). Full recovery was defined as the combination of clinical recovery and personal recovery. First, we examined the factors at baseline associated with each aspect of recovery. Then, we conducted multivariable models on the correlates of stable clinical recovery, stable personal recovery, and stable full recovery after one year. At baseline, clinical recovery and personal recovery were characterized by distinct patterns of outcome (i.e. better objective outcomes but no difference in subjective outcomes for clinical recovery, the opposite pattern for personal recovery, and better overall outcomes for full recovery). We found that clinical recovery and personal recovery predicted each other over time (baseline personal recovery for stable clinical recovery at one year; P =. 026, OR = 4.94 [1.30-23.0]; baseline clinical recovery for stable personal recovery at one year; P =. 016, OR = 3.64 [1.31-11.2]). In short, given the interaction but also the degree of difference between clinical recovery and personal recovery, psychosocial treatment should target, beyond clinical recovery, subjective aspects such as personal recovery and depression to reach full recovery. © 2021 The Author(s). Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved.Sorbonne Universités à Paris pour l'Enseignement et la RechercheFondaMental-Cohorte

    Handedness as a neurodevelopmental marker in schizophrenia: Results from the FACE-SZ cohort

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    Objectives: High rates of non-right-handedness (NRH) including mixed-handedness have been reported in neurodevelopmental disorders. In schizophrenia (SZ), atypical handedness has been inconsistently related to impaired features. We aimed to determine whether SZ subjects with NRH and mixed-handedness had poorer clinical and cognitive outcomes compared to their counterparts. Methods: 667 participants were tested with a battery of neuropsychological tests, and assessed for laterality using the Edinburg Handedness Inventory. Clinical symptomatology was assessed. Learning disorders and obstetrical complications were recorded. Biological parameters were explored. Results: The prevalence of NRH and mixed-handedness was high (respectively, 42.4% and 34.1%). In the multivariable analyses, NRH was associated with cannabis use disorder (p = 0.045). Mixed-handedness was associated with positive symptoms (p = 0.041), current depressive disorder (p = 0.005)), current cannabis use (p = 0.024) and less akathisia (p = 0.019). A history of learning disorder was associated with NRH. No association was found with cognition, trauma history, obstetrical complications, psychotic symptoms, peripheral inflammation. Conclusions: Non-right and mixed-handedness are very high in patients with SZ, possibly reflecting a neurodevelopmental origin. NRH is associated with learning disorders and cannabis use. Mixed-handedness is associated with positive symptoms, current depressive disorder, cannabis use and less akathisia. However, this study did not confirm greater cognitive impairment in these patients. © 2021 Informa UK Limited, trading as Taylor & Francis Group.Sorbonne Universités à Paris pour l'Enseignement et la RechercheFondaMental-Cohorte

    Precision-medicine findings from the FACE-SZ cohort to develop motivation-enhancing programs in real-world schizophrenia

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    Background: In people with schizophrenia, major areas of everyday life are impaired, including independent living, productive activities, social relationships and overall quality of life. Enhanced understanding of factors that hinder real-life functioning is vital for treatments to translate into more positive outcomes. Aim: The goal of the present study was to identify factors associated with motivation deficits in real-life schizophrenia, and to assess its contribution to impaired functioning and quality of life. Methods: Based on previous literature and clinical experience, several factors were selected and grouped into factors potentially explaining motivation deficits. Some of these variables were never investigated before in relationship with motivation deficits. Results: In 561 patients with schizophrenia of the national FACE-SZ cohort living in the community, 235 (41.9%) reported severe motivation deficits. These deficits were found to be significantly associated with impaired socially useful activities, psychological and physical quality of life (in almost all domains), alcohol use disorder (aOR = 2.141, p = 0.021), severe nicotine dependence (aOR = 2.906, p < 0.001) independently of age and sex. No significant association was found for body mass index, metabolic syndrome or physical activity level. In the second model, we identified the following modifiable factors associated with motivation deficits: history of suicide attempt (aOR = 2.297, p = 0.001), positive symptoms (aOR = 1.052, p = 0.006), current major depressive episode (aOR = 2.627, p < 0.001), sleep disorders (aOR = 1.474, p = 0.024) and lower medication adherence (aOR = 0.836, p = 0.001) independently of gender, current alcohol use disorder, second-generation antipsychotics and akathisia. No significant association was found for negative symptoms, childhood trauma and inflammation. These results were maintained after removing patients with schizoaffective disorders or those with major depressive disorder. Interpretation: Motivation deficits are frequent and remain persistent unmet need in real-world schizophrenia that should be addressed in future guidelines. Based on our results, literature and clinical experience, we recommend to address in priority major depression, sleep, suicide, positive symptoms (when present and as early as possible) and medication adherence to improve motivation deficits of schizophrenia. © 2022 Informa UK Limited, trading as Taylor & Francis Group.Sorbonne Universités à Paris pour l'Enseignement et la RechercheFondaMental-Cohorte

    Immuno-metabolic profile of patients with psychotic disorders and metabolic syndrome. Results from the FACE-SZ cohort

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    Background: Metabolic syndrome (MetS) is a highly prevalent and harmful medical disorder often comorbid with psychosis where it can contribute to cardiovascular complications. As immune dysfunction is a key shared component of both MetS and schizophrenia (SZ), this study investigated the relationship between immune alterations and MetS in patients with SZ, whilst controlling the impact of confounding clinical characteristics including psychiatric symptoms and comorbidities, history of childhood maltreatment and psychotropic treatments. Method: A total of 310 patients meeting DSM-IV criteria for SZ or schizoaffective disorders (SZA), with or without MetS, were systematically assessed and included in the FondaMental Advanced Centers of Expertise for Schizophrenia (FACE-SZ) cohort. Detailed clinical characteristics of patients, including psychotic symptomatology, psychiatric comorbidities and history of childhood maltreatment were recorded and the serum levels of 18 cytokines were measured. A penalized regression method was performed to analyze associations between inflammation and MetS, whilst controlling for confounding factors. Results: Of the total sample, 25% of patients had MetS. Eight cytokines were above the lower limit of detection (LLOD) in more than 90% of the samples and retained in downstream analysis. Using a conservative Variable Inclusion Probability (VIP) of 75%, we found that elevated levels of interleukin (IL)-6, IL-7, IL-12/23 p40 and IL-16 and lower levels of tumor necrosis factor (TNF)-α were associated with MetS. As for clinical variables, age, sex, body mass index (BMI), diagnosis of SZ (not SZA), age at the first episode of psychosis (FEP), alcohol abuse, current tobacco smoking, and treatment with antidepressants and anxiolytics were all associated with MetS. Conclusion: We have identified five cytokines associated with MetS in SZ suggesting that patients with psychotic disorders and MetS are characterized by a specific “immuno-metabolic” profile. This may help to design tailored treatments for this subgroup of patients with both psychotic disorders and MetS, taking one more step towards precision medicine in psychiatry. © 2022 The AuthorsImmuno-Génétique, Inflammation, retro-Virus, Environnement : de l'étiopathogénie des troubles psychotiques aux modèles animauxRéseau d'Innovation sur les Voies de Signalisation en Sciences de la Vi
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