Severity of restless legs syndrome is inversely correlated with echogenicity of the substantia nigra in different neurodegenerative movement disorders. A preliminary observation

Objective: Hyperechogenicity of the substantia nigra is a frequent observation on transcranial sonography in Parkinson's disease and Machado-Joseph disease patients. Additionally, restless legs syndrome is a sleep disorder that is also frequently found in both diseases. Autopsy studies have demonstrated increased SN iron content in hyperechogenic substantia nigra. Iron storage is also known to be involved in restless legs syndrome. We formally compared echogenicity of the substantia nigra with restless legs syndrome in Parkinson's disease and Machado-Joseph disease patients. Methods: Transcranial brain sonography was performed in a sample of Parkinson's disease and Machado-Joseph disease patients, and findings then correlated with the presence and severity of restless legs syndrome. Results: There was a continuum of substantia nigra echogenicity among groups (Parkinson's disease versus Machado-Joseph disease versus controls) and sub-groups (Parkinson's disease with and without restless legs syndrome versus Machado-Joseph disease with and without restless legs syndrome) as well as a statistically significant negative correlation between restless legs syndrome severity and substantia nigra echogenicity (p<0.001). Conclusions: These preliminary observations demonstrate that the severity of RLS may be influenced by nigral iron load reflected by substantia nigra echogenicity in different neurodegenerative movement disorders. (C) 2012 Elsevier B.V. All rights reserved.

The legs: a key to bird evolutionary success

Birds are the most diverse and largest group of extant tetrapods. They show marked variability, yet much of this variation is superficial and due to feather and bill color and shape. Under the feathers, the skeleto-muscular system is rather constant throughout the bird group. The adaptation to flight is the explanation for this uniformity. The more obvious morphological adaptations for flight are the wings, but the trunk is always rigid, the tail is short and the neck is flexible, since all these features are correlated with flying behaviour. Unrelated to the exigencies of flight, the legs always have three long bones, and all the birds walk on their toes. This leg structure is a striking plesiomorphic feature that was already present in related dinosaurs. The multi-purpose potential of the legs is the result of the skeletal architecture of a body with three segmented flexed legs. This configuration provides mechanical properties that allow the use of the legs as propulsive, paddling, foraging or grooming tools. It is the association of diverse modes of locomotion-walking, running, hopping, flying and swimming-that have enabled the birds to colonize almost all the environments on Earth.

Loading a K-39 crossed optical dipole trap from a magneto-optical trap

In this work, we have applied sub-Doppler laser cooling to a K-39 magneto-optical trap in order to load a 1071 nm crossed optical dipole trap. The number of atoms loaded into the dipole trap was characterized as a function of the frequency and intensity of the cooling and repump laser beams. For the optimum conditions, the dipole trap has about 2 x 10(6) atoms at an atomic density of 2 x 10(12) cm(-3), with a temperature of about 10 mu K. This technique is a very simple procedure to load a K-39 optical dipole trap without a previous magnetic evaporative cooling step and may find application in other atomic physic systems.