Tilted-potential photonic crystal cavities for integrated quantum photonics.

We propose and investigate a new type of photonic crystal (PhC) cavity for integrated quantum photonics, which provides tailored optical modes with both confined and extended spatial components. The structures consist of elongated PhC cavities in which the effective index of refraction is varied quasi-linearly along their axis, implemented by systematic lateral shifts of the PhC holes. The confined modes have approximately Airy-function envelopes, exhibiting single peaks and extended tails, which is useful for optimizing single photon extraction and transmission in integrated quantum photonic devices. The measured spectrally resolved near-field patterns of such devices show the expected spatial and resonance wavelength behavior, in agreement with numerical simulations of the Airy-Bloch modes. The effects of fabrication-induced disorder on the mode features are also analyzed and discussed. Selective excitation of specific Airy-Bloch modes using integrated, site-controlled quantum dots as localized light sources is demonstrated. Based on the tilted-potential cavity, multiple-QD single photon emitters exploiting wavelength division multiplexing are proposed.

[The Paquid research program on the epidemiology of dementia. Methods and initial results]. / Le programme de recherche Paquid sur l'épidémiologie de la démence. Méthodes et résultats initiaux.

Paquid is an epidemiological study designed to gather and follow up a cohort of 4,000 elderly subjects (65 years and older) living at home in order to study normal and pathological brain aging. These subjects were randomly chosen in the general population of 75 communities of South-Western France. We present the results of the data collected from 2,792 subjects on the prevalence and the correlates of clinically diagnosed dementia. The DSM III criteria for dementia were met by 101 subjects (3.62 p. 100). These cases were reviewed by a neurologist to confirm the diagnosis and to determine the cause of dementia using the NINCDS-ADRDA criteria. Forty-three subjects were classified as probable Alzheimer's disease; 8 as possible Alzheimer's disease; 5 as vascular dementia; 5 as Parkinson's disease with dementia; 2 as alcoholic dementia; 2 as "dementified psychosis"; and 1 unclassified. Fifteen patients refused to be examined by the neurologist, 18 were false-positives, and 2 died before the neurologists visit. Using the NINCDS-ADRDA criteria, the prevalence of dementia was as low as 1.6 p. 100. The prevalence of probable Alzheimer's disease decreased dramatically as educational level increased, lung 5.4 p. 100 for subjects with no education, 1.7 p. 100 for subjects with grade school level, 0.4 p. 100 for subjects with high school level and 0.4 p. 100 for subjects with university degrees. The relationship between dementia and educational level is still controversial in the literature. In this study the sample was large and randomly selected; all the demented cases fulfilled the NINCDS-ADRDA criteria. This suggests that educational level is indeed an important correlate of dementia in the French elderly community.

Morphological study of the aging human peripheral nerve.

The superficial peroneal nerve from 46 elderly patients was studied by light and electron microscopy. Like most elderly people, these patients displayed evidence of varying degrees of peripheral nervous system dysfunction, but they were not suffering from any disease known to alter the peripheral nerve. A quantitative study showed that myelinated fiber loss predominated in the large diameter group. In the majority of cases, clusters of regenerating myelinated fibers were numerous. On the other hand, Wallerian-like degeneration aspects, segmental demyelination figures and axonal organelle accumulation were relatively rare. Unmyelinated fibers were also notably damaged in most cases. There was moderate reduplication of endoneurial vascular basement membrane.

[Salsolinol, an endogenous molecule. Possible implications in alcoholism, Parkinson's disease and pain]. / Le salsolinol, molécule endogène. Possibles implications dans l'alcoolisme, la maladie de Parkinson et la douleur.

Salsolinol can be formed either by condensation of dopamine with acetaldehyde, or by condensation of dopamine with pyruvic acid followed by decarboxylation. Salsolinol has a complex pharmacologic profile. Its opium-like activity may be related to alcohol dependency and to the effectiveness of naloxone during acute alcohol intoxication. Because they had noticed that alcoholism and Parkinson's disease rarely coexist, the authors undertook a study to confirm this fact and attempt to explain it by implicating salsolinol. Urinary excretion of salsolinol was found to increase following ingestion of alcohol, as well as in Parkinson patients under L-dopa treatment. The authors also found that urinary salsolinol was very low in untreated patients with Parkinson's disease. Salsolinol was detected in a number of foods and beverages. Separate assays of enantiomeres showed that the S enantiomere predominates in some foods whereas the R enantiomere is more abundant in humans. Lastly, the antinociceptive effects of salsolinol and its enantiomeres were studied in mice and antidepressant effects were evidenced using predictive tests.