Demographic, clinical, and service-use characteristics related to the clinician’s recommendation to transition from child to adult mental health services

Purpose: The service configuration with distinct child and adolescent mental health services (CAMHS) and adult mental health services (AMHS) may be a barrier to continuity of care. Because of a lack of transition policy, CAMHS clinicians have to decide whether and when a young person should transition to AMHS. This study describes which characteristics are associated with the clinicians’ advice to continue treatment at AMHS. Methods: Demographic, family, clinical, treatment, and service-use characteristics of the MILESTONE cohort of 763 young people from 39 CAMHS in Europe were assessed using multi-informant and standardized assessment tools. Logistic mixed models were fitted to assess the relationship between these characteristics and clinicians’ transition recommendations. Results: Young people with higher clinician-rated severity of psychopathology scores, with self- and parent-reported need for ongoing treatment, with lower everyday functional skills and without self-reported psychotic experiences were more likely to be recommended to continue treatment. Among those who had been recommended to continue treatment, young people who used psychotropic medication, who had been in CAMHS for more than a year, and for whom appropriate AMHS were available were more likely to be recommended to continue treatment at AMHS. Young people whose parents indicated a need for ongoing treatment were more likely to be recommended to stay in CAMHS. Conclusion: Although the decision regarding continuity of treatment was mostly determined by a small set of clinical characteristics, the recommendation to continue treatment at AMHS was mostly affected by service-use related characteristics, such as the availability of appropriate services

Cohort profile : demographic and clinical characteristics of the MILESTONE longitudinal cohort of young people approaching the upper age limit of their child mental health care service in Europe

Purpose: The presence of distinct child and adolescent mental health services (CAMHS) and adult mental health services (AMHS) impacts continuity of mental health treatment for young people. However, we do not know the extent of discontinuity of care in Europe nor the effects of discontinuity on the mental health of young people. Current research is limited, as the majority of existing studies are retrospective, based on small samples or used non-standardised information from medical records. The MILESTONE prospective cohort study aims to examine associations between service use, mental health and other outcomes over 24 months, using information from self, parent and clinician reports. Participants: Seven hundred sixty-three young people from 39 CAMHS in 8 European countries, their parents and CAMHS clinicians who completed interviews and online questionnaires and were followed up for 2 years after reaching the upper age limit of the CAMHS they receive treatment at. Findings to date: This cohort profile describes the baseline characteristics of the MILESTONE cohort. The mental health of young people reaching the upper age limit of their CAMHS varied greatly in type and severity: 32.8% of young people reported clinical levels of self-reported problems and 18.6% were rated to be ‘markedly ill’, ‘severely ill’ or ‘among the most extremely ill’ by their clinician. Fifty-seven per cent of young people reported psychotropic medication use in the previous half year. Future plans: Analysis of longitudinal data from the MILESTONE cohort will be used to assess relationships between the demographic and clinical characteristics of young people reaching the upper age limit of their CAMHS and the type of care the young person uses over the next 2 years, such as whether the young person transitions to AMHS. At 2 years follow-up, the mental health outcomes of young people following different care pathways will be compared. Trial registration number: NCT03013595

Electrochemical reactions of tin based anode materials in alkali-ion batteries

International audienc

How Mössbauer spectroscopy can improve Li-ion batteries

International audienc

Structure and chemical bonding in Zr-doped anatase TiO2 nanocrystals

Zirconium-doped anatase TiO2 nanopowders and nanoceramics with particle sizes between 12 and 30 nm were investigated by EXAFS spectroscopy. Furthermore, ab initio calculations based on density functional theory were performed to analyze changes in the electronic structure due to Zr doping. Zr is dissolved on substitutional bulk sites with a slight increase of the bond lengths of the inner coordination shells. The Debye-Waller factors show that the nanocrystallites are highly ordered. There is no indication for defect states or band gap changes with Zr doping

Electrodes négatives de batteries lithium-ion (les intermétalliques de l'étain)

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Électrodes négatives pour batteries Li-ion à base de FeSn2 (performances, Mécanismes et Vieillissement.)

Comme dispositif de stockage de l'énergie, les batteries Li-ion possèdent de nombreux avantages et en particulier une densité d'énergie élevée. Toutefois, la recherche de nouveaux matériaux d'électrode reste nécessaire pour améliorer les performances. Ce travail concerne les matériaux d'électrode négative avec pour objectif l'augmentation de leur capacité. Dans ce but nous nous sommes intéressés à un composé intermétallique à base d'étain : FeSn2. Nous avons effectué la synthèse de ce matériau par différents procédés afin d'obtenir des microparticules et un matériau nanostructuré. L'étude des mécanismes électrochimiques a montré que pour ces deux types de matériaux la première décharge constituait une étape essentielle de restructuration de l'électrode aboutissant à la formation in situ d'un nanocomposite Fe/Li7Sn2. Le suivi quantitatif de la réaction de conversion, responsable de cette transformation, a été effectué par spectrométrie Mössbauer in situ et operando grâce à une nouvelle cellule électrochimique que nous avons développée. D'autres techniques ont été utilisées : DRX et spectrométrie d'impédance in situ, SQUID et XPS. En associant ces différentes techniques nous avons montré que les cycles de charge/décharge étaient basés sur une réaction réversible entre Li7Sn2 et LixSn riche en étain sans reformation de FeSn2. Ce résultat diffère des mécanismes observés pour CoSn2 et Ni3Sn4 et pourrait expliquer la perte progressive de capacité généralement observée avec FeSn2. Toutefois, les performances sont intéressantes avec une capacité de 400-500mAh/g sur 50 cycles entre C/10 et 10C. Enfin, nous avons mis en évidence un phénomène de vieillissement de l'électrode en fin de décharge qui provoque sa délithiation irréversible.Li-ion batteries are rechargeable energy storage systems with high energy density. However, new electrode materials are needed in order to improve the electrochemical performances. This thesis is devoted to a tin based intermetallic compound as negative electrode for Li-ion batteries: FeSn2. Different synthesis methods were used in order to obtain microsized particles and nanostructured materials. The study of the electrochemical mechanisms shows that for both types of materials the first discharge is an essential restructuring step leading to the in situ formation of a Fe/Li7Sn2 nanocomposite. This transformation is due to a conversion reaction that was quantitatively characterized by Mössbauer spectroscopy from in situ and operando measurements. A new cheap and reliable electrochemical cell was developed for these measurements. Other techniques have also been used: in situ XRD and impedance spectroscopy, XPS and SQUID. By combining these tec hniques we have shown that the charge/discharge cycles were based on a reversible reaction between Li7Sn2 and tin-rich LixSn without back reaction with iron nanoparticles. This result is rather surprising because it differs from the mechanisms observed for CoSn2 and Ni3Sn4 but could explain the progressive loss of capacity usually observed with FeSn2. However, interesting performances were obtained with a capacity of 400-500mAh/g for 50 cycles and lithium rates between C/10 and 10C. Finally, we have identified aging process for the electrode at the end of discharge that causes irreversible delithiation.MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Étude théorique des matériaux d'électrode positive négative pour batteries Li-ion

Ce mémoire est consacré à l'étude théorique des matériaux de cathode pour batteries Li-ion de structure olivine LiMPO4 (M=Mn, Fe, Co, Ni), des phases délithiées MPO4 et des phases mixtes LiFexMn1-xPO4, FexMn1-xPO4 et LiFexCo1-xPO4. La stabilité des phases magnétiques et les paramètres de maille théoriques ont été déterminés par la méthode des pseudopotentiels et comparés aux données expérimentales. Les structures électroniques ont été calculées par une méthode tout électron et analysées en termes d'hybridation des orbitales atomiques Ces résultats ont permis d'interpréter les spectres de photoélectrons X et d'absorption des rayons X, en particulier les modifications réversibles associées aux cycles de lithiation/délithiation. Les effets de la polarisation de spin et de la corrélation électronique ont été discutés. Enfin, le calcul des paramètres Mössbauer du 57Fe a montré qu'un accord quantitatif entre les résultats théoriques et les données expérimentales nécessitait la prise en compte de ces deux effets. Ce type de calcul a permis de prédire et d'expliquer que la transformation LiFePO4 FePO4 s'accompagnait de la variation du gradient de champ électrique Vzz d'une extrémité à l'autre de l'échelle Mössbauer pour 57Fe.This thesis is devoted to the theoretical study of the cathode materials for Li-ion batteries with olivine structure LiMPO4 (M=Mn, Fe, Co, Ni), the delithiated phases MPO4 and the mixed phases LiFexMn1-xPO4, FexMn1-xPO4 and LiFexCo1-xPO4. The magnetic phase stability and lattice parameters were theoretically determined from pseudopotential calculations and the results have been compared with experiments. Electronic structures were obtained from all electron calculations and analyzed in terms of orbital hybridization. The results have been used for the interpretation of X-ray photoemission and X-ray absorption spectra, especially changes due to lithiation/delithiation cycles. Effects of spin polarization and electronic correlation on the electronic structures have been also discussed. It has been shown that ab initio calculations of the 57Fe Mössbauer parameters also require these two effects in order to obtain a quantitative agreement with experiments. Finally, it was found that LiFePO4 FePO4 transformation involves a dramatic change of the electric field gradient VZZ from one end to the other of the 57Fe Mössbauer scale.MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Mécanismes de vieillissement des anodes à base de FeSn2 pour batteries Li-ion

Les intermétalliques d’étain ont été proposés comme matériaux d’anode pour batteries Li-ion à forte densité d’énergie car leur capacité spécifique est bien supérieure à celle des anodes commerciales à base de carbone. Le mécanisme électrochimique est basé sur la transformation irréversible de FeSn2 en un composite formé de nanoparticules de fer et de Li3.5Sn lors de la première lithiation, puis de réactions réversibles modifiant la composition de Li3.5Sn, les particules de fer assurant la dispersion de ces particules à base d’étain [1]. Cependant, nous avons observé que l’électrode lithiée était instable dans le temps conduisant à l’autodécharge progressive de la batterie [2]. Ce phénomène de vieillissement a été caractérisé par spectrométrie Mössbauer du 57Fe et de 119Sn, par spectroscopie d’impédance et par mesures magnétiques (Figure 1). On montre que le composite Fe/Li3.5Sn se délithie progressivement au cours du temps conduisant à un composite faiblement lithié Fe/LixSn avec x<1. Les nanoparticules de fer sont stables et ne réagissent pas avec LixSn. Les atomes de lithium libérés réagissent avec l’électrolyte et modifient la morphologie de la couche SEI (Surface Electrolyte Interphase) située à la surface des particules LixSn du composite.[1] M. Chamas, M. T. Sougrati, C. Reibel, P.E. Lippens, Chem. Mater. 25, 2410 (2015). [2] M. Chamas, A. Mahmoud, J. Tang, S. Panero, M. T. Sougrati, P. E. Lippens, J. Phys Chem. C 121, 217 (2017)

Electrochemical impedance study of the solid electrolyte interphase in MnSn2 based anode for Li-ion batteries

Abstract This work reports the interfacial properties of nanostructured MnSn2 as anode material for Li-ion batteries in order to explain ageing phenomena. The impedance measurements show variations of the solid electrolyte interphase (SEI) resistance during the first cycle that are interpreted from changes in thickness and/or porosity of the SEI film. These changes are mainly due to the degradation of the electrolyte at the beginning of the first discharge and to the de-alloying reaction of Li7Sn2 operating during the first part of the charge that causes strong volume variations. However, a rather stable SEI was obtained during the reformation of MnSn2 in the second part of the charge, which is peculiar to this compound. Finally, capacity fading is related to the continuous growth of the SEI during cycling