On the chemical potential of a component in a metastable phase--application to Li-storage in the RuO2-Li system.

The chemical potential of a component of a binary metastable compound is considered in the single-phase and in the compositionally non-variant two-phase regime. A detailed thermodynamic analysis reveals striking differences for identical nominal compositions. Without the loss of generality the chemical potential of Li in Li containing compounds is referred to. In the single-phase regime an increased Gibbs energy of the metastable phase, compared with the stable phase, leads to an increased chemical potential of lithium, as long as we can ignore the dependence of the excess value on composition. If, in the same approximation, this metastable phase is in two-phase equilibrium with a binary phase more rich in Li, a decrease in the chemical potential and hence an inversion of the sign of the cell voltage in a Li-based battery is predicted. To be specific we consider Li-storage within RuO(2) as well as in the pseudo-binary two-phase system RuO(2)-LiRuO(2). A significantly greater cell voltage vs. Li is observed in the two-phase region if amorphous RuO(2) is used instead of crystalline RuO(2), in contrast to the single-phase system. A possible applicability of metastable phases for Li-based batteries is discussed.

[Progressive supranuclear palsy: a clinical, natural history and disability study]. / Paralysie supranucléaire progressive: étude clinique, histoire naturelle et progression du handicap.

We studied the clinical features, the natural history and disability in 47 progressive supranuclear palsy patients and brain imaging aspects by routinely performed MRI in a subgroup of 25. Unexplained falls together with atypical parkinsonism (symmetric, levodopa unresponsive without resting tremor) are good clinical pointers of the early diagnosis, since they occurred within the first year. Cognitive slowness and unspecific visual complains are also early symptoms, while usual cardinal signs such as supranuclear palsy are more delayed. Blepharospasm and eyelid opening apraxia as well as deep sighs are also quite characteristic clinical features (1/3 of cases). Cardinal signs (falls, pseudobulbar signs, supranuclear gaze palsy) worsened rapidly (20 to 30 months) towards a major disability. In the 20 patients deceased during follow-up, the mean survival time was about 5 years. The MRI study showed typical cortical fronto-temporo-parietal atrophy, mesencephalic and quadrigeminal plate atrophy with third ventricle dilatation. In conclusion, unexplained falls associated with atypical parkinsonism are contributive for the early clinical diagnosis. Non specific visual complains could be useful pointers in the absence of supranuclear ophthalmoplegia. MRI contributes to the clinical diagnosis even in the first 3 years of the disease course.

Routine MRI for the differential diagnosis of Parkinson's disease, MSA, PSP, and CBD.

We assessed the usefulness of routine MRI for the differential diagnosis of Parkinson's disease (PD) with "atypical" parkinsonian syndromes in everyday clinical practice. We studied routinely performed MRI in PD (n = 32), multiple system atrophy (MSA, n = 28), progressive supranuclear palsy (PSP, n = 30), and corticobasal degeneration (CBD, n = 26). From a preliminary analysis of 26 items, 4 independent investigators rated 11 easily recognizable MRI pointers organized as a simple scoring system. The frequency, severity and inter-rater agreement were determined. The total severity score was subdivided into "cortical", "putaminal", "midbrain", and "pontocerebellar" scores. The frequency of putaminal involvement (100%) and vermian cerebellar atrophy (45%) was significantly higher in MSA, but that of cortical atrophy (50%), midbrain atrophy and 3(rd) ventricle enlargement (75%) was higher in PSP and CBD. The median total score fairly differentiated "atypical" parkinsonian syndromes from PD (positive predictive value-PPV-90%). However, the median total score was unable to differentiate atypical parkinsonian syndromes each other. The "cortical" score distinguished CBD and PSP from MSA with a fair PPV (>90%). The PPV of the "putaminal" score was high (70%) for the differential diagnosis of MSA with PSP and CBD. The "midbrain" score was significantly higher in PSP and CBD compared to MSA. These results are in accordance with the underlying pathology found in these disorders and demonstrate that a simple MRI scoring procedure may help the neurologist to differentiate primary causes of parkinsonism in everyday practice.

[Evaluation of the efficacy of foraminal infusions of corticosteroids guided by computed tomography in the treatment of radicular pain by foraminal injection]. / Evaluation de l'efficacité des infiltrations foraminales de corticoïdes guidées sous tomodensitométrie, dans le traitement des radiculalgies par conflit foraminal.

PURPOSE: To evaluate the efficacy of foraminal steroid injections performed under CT guidance for the management of radicular pain. METHODS: Periganglionic infiltrations were performed in 160 patients with radicular pain refractory to medical treatment. Imaging showed either degenerative foraminal stenosis, herniated disk or postsurgical fibrosis. RESULTS: 102 patients (63.8%) had significant pain reduction. Pain relief was lasting in 68 (66.6%). CT showed the position of the needle tip, as well as the diffusion of the therapeutic compounds. CONCLUSION: We consider that CT-guided periganglionic steroid injections should be an integral part of the management strategy for radicular pain resistant to medical treatment.