High conductivity organic thin films for spintronics: the interface resistance bottleneck.

Highly electrochemically doped poly(2,5-bis(3-dodecyl-2-yl)-thieno[3,2-b]thiophene (pBTTT) thin films exhibiting remarkably high conductivities values reaching 3000-5000 Ω(-1) cm(-1) are investigated. Experimental evidence of delocalized transport properties of this material at the onset of metallicity makes it an ideal candidate for spin valve device integration. Nevertheless, the interface resistance between the polymer and metallic electrodes is orders of magnitudes larger than the expected spin resistance of the active channel. This prevents the collection of a spin current. This finding can explain the lack of success in making lateral organic spin valves reported in the literature, especially the related absence of spin signals in non-local spin valve and Hanle current measurements in organic thin films.

[Emotional reactivity in euthymic bipolar patients]. / Réactivité émotionnelle chez les patients bipolaires en phase de normothymie.

BACKGROUND: Euthymic states in bipolar disorders are usually considered to be lacking serious psychiatric disorders. Moreover, recent results prove the need to take an interest in a potential emotional dysregulation during these intercrisis periods. Therefore, it seems relevant not only to focus on the emotions tonality (sadness/euphoria) felt by patients, but also on the intensity of their emotional background. Several reasons argue for a disturbance of emotional reactivity in euthymic bipolar patients. First, most bipolar patients spontaneously claim they have a higher sensitivity than average, which may lead to extreme emotional reactions, even during intercrisis periods. Secondly, the emotional reactivity is a way to raise the question of the bipolar patients' vulnerability to stress in euthymic periods. Several studies have shown the impact of stressful life events on the rate of relapse into bipolar disorders. The aim of this study is to examine the emotional reactivity of euthymic bipolar patients in comparison with a control group, using a test of emotional induction. Our hypothesis is that euthymic bipolar patients have a higher emotional reactivity than controls. METHOD: One hundred and forty-five subjects were recruited: 90 controls and 55 euthymic bipolar patients. The patients were interviewed by a trained psychologist using the French version of the DIGS providing DSM-IV diagnosis. The euthymic state was confirmed with both MADRS (score<12) and Bech's Manic Scale (score<4). The subjective emotional reactivity of the subjects was assessed using a method of emotional induction, based on viewing a set of 18 (positive, negative or neutral) pictures. The subjects have to appreciate the valence (pleasant, neutral or unpleasant thoughts) and assess the arousal (degree of emotion triggered by each picture). RESULTS: On average, euthymic bipolar patients report the same valence and arousal to positive (F [1.143]=0.18, p=0.68) and negative (F [1.143]=0.52, p=0.47) pictures as control subjects. Neutral pictures, however, were considered more pleasant and moving by euthymic bipolar patients than by control subjects (F [1.143]=8.40, p=0.004). CONCLUSION: Euthymic bipolar patients seem to present an emotional hyperactivity which occurs especially in neutral situations. These results partly corroborate outcomes of other authors, while providing a new methodology through the emotional induction test. The highlight of emotional hyperreactivity during intercrisis periods allows us to understand differently the topic of specific vulnerability to stress of bipolar patients. This hypersensitivity could lead to thymic decompensations and could be linked with an emotional dysregulation, potential endophenotype of the bipolar pathology. Beyond the interest in understanding the physiopathology of the bipolar disorder, it could be associated with several clinical applications as well as in the psychoeducational field and in the screening of the individual risk within the family of bipolar subjects.

Factors affecting satisfaction among community-based hospice volunteer visitors.

Trained volunteers are an essential component in the delivery of care to clients and families facing a terminal and/or life-threatening illness. As the need for hospice care increases, so does the need to increase the number of volunteers available for visiting. Hospice of London, which is a community based hospice, proposed that volunteers who felt satisfied would remain with the organization longer, thereby, decreasing the costs associated with training new volunteers and enhancing the ability of the agency to provide high-quality volunteer client matches. Accordingly, a survey was conducted in August 1992 to determine which factors were related to hospice volunteer satisfaction. One hundred and five volunteer were surveyed over the telephone. Results demonstrated a positive correlation between satisfaction and feeling like a team member, receiving feedback from staff, feeling valuable and having the volunteer's expectations match the position. Differences in the factors related to satisfaction were noted when the groups were divided by age and gender.