A thermogravimetric study of the reactions of molybdenum disilicide with anhydrous hydrogen fluoride and fluorine

The results of a thermogravimetric study into the dry fluorination of molybdenum disilicide, MoSi2, using hydrogen fluoride and dilute fluorine gas as fluorinating agents are reported. The reaction between molybdenum disilicide and fluorine follows the thermodynamically preferred route, viz. the formation of the volatile molybdenum hexafluoride along with gaseous silicon tetrafluoride, with the reaction starting just below 200 8C. The reaction with hydrogen fluoride yields solid molybdenum metal and gaseous silicon tetrafluoride, similarly thermodynamically predicted, above 250 8C. No reaction is observed at low temperatures where solid molybdenum trifluoride is expected to form. The results of a kinetic analysis of the data for the reaction with hydrogen fluoride are reported. In the range 250–450 8C the kinetics are chemical reaction controlled. Above this, up to 700 8C, the rate is controlled by diffusion through the stagnant gas films surrounding the solid particles. Evidence for a third, un-quantified, hightemperature mechanism is given.South African National Research Foundation (NRF)http://www.elsevier.com /locate/fluorhb201

Psychometric properties of a generic, patient-centred palliative care outcome measure of symptom burden for people with progressive long term neurological conditions

Background There is no standard palliative care outcome measure for people with progressive long term neurological conditions (LTNC). This study aims to determine the psychometric properties of a new 8-item palliative care outcome scale of symptom burden (IPOS Neuro-S8) in this population. Data and Methods Data were merged from a Phase II palliative care intervention study in multiple sclerosis (MS) and a longitudinal observational study in idiopathic Parkinson's disease (IPD), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). The IPOS Neuro-S8 was assessed for its data quality, score distribution, ceiling and floor effects, reliability, factor structure, convergent and discriminant validity, concurrent validity with generic (Palliative care Outcome Scale) and condition specific measures (Multiple Sclerosis Impact Scale; Non-motor Symptoms Questionnaire; Parkinson's Disease Questionnaire), responsiveness and minimally clinically important difference. Results Of the 134 participants, MS patients had a mean Extended Disability Status Scale score 7.8 (SD = 1.0), patients with an IPD, MSA or PSP were in Hoehn & Yahr stage 3±5. The IPOS Neuro-S8 had high data quality (2% missing), mean score 8 (SD = 5; range 0±32), no ceiling effects, borderline floor effects, good internal consistency (Cronbach's α = 0.7) and moderate test-retest reliability (intraclass coefficient = 0.6). The results supported a moderately correlated two-factor structure (Pearson's r = 0.5). It was moderately correlated with generic and condition specific measures (Pearson's r: 0.5±0.6). There was some evidence for discriminant validity in IPD, MSA and PSP (p = 0.020), and for good responsiveness and longitudinal construct validity. Conclusions IPOS Neuro-S8 shows acceptable to promising psychometric properties in common forms of progressive LTNCs. Future work needs to confirm these findings with larger samples and its usefulness in wider disease groups

Trois approches de communication médecin-patient et prévention : quel modèle pour quelle situation ? [Three approaches to doctor-patient communication and prevention : Which model for which situation ?]

Doctors learn different communication approaches for use during prevention consultations to promote healthy habits, so as to set up a partnership and to promote patient autonomy. Three of these approaches are shared decision making, when there is more than one reasonable choice, motivational interviewing, principally for behaviour change and therapeutic education, a pedagogical approach helping patients develop skills so that they may have a better management of their chronic illness. This article presents an overview of the commonalities and the differences between these approaches, often considered separately, nevertheless they are complementary and in practice, using elements of all three during a consultation could improve preventative care