Cyclotron braid group structure for composite fermions.

Although they describe properties of 2D Hall systems in the fractional quantum regime well, composite fermions suffer from the unexplained character of the localized magnetic field flux-tubes attached to each particle in order to reproduce the Laughlin correlations via Aharonov-Bohm phase shifts. The identification of the cyclotron trajectories of 2D charged particles as accessible classical trajectories within the braid group approach at the magnetic field presence, allows, however, for the avoidance of the construction with fluxes. We introduce cyclotron braid subgroups for charged 2D systems at the fractional Landau-level filling associated in a more natural way with composite fermions without invoking field flux-tubes. The Aharonov-Bohm phase shifts caused by fluxes are replaced with the phase gain due to multi-loop cyclotron trajectories unavoidably occurring at the fractional filling of 1/p (p is an odd integer). Another approach to composite particles, using so-called vortices, is also discussed from the point of view of the cyclotron braid group description (for both odd and even p integers).

Different presentations of late-detected phenylketonuria in two brothers with the same R408W/R111X genotype in the PAH gene.

Although the clinical heterogeneity of phenylketonuria (PKU) is well established, some questions about this condition remain. Subjects from the same family who share the same mutations in the phenylalanine hydroxylase (PAH) gene are expected to display similar disease courses, and therefore, when blood phenylalanine (Phe) levels, genotype and dietary treatment are all similar, differences in patient outcomes require additional explanations. The present authors describe two entirely different courses of late-detected PKU in two brothers with the same R408W/R111X genotype in the PAH gene. The older sibling was diagnosed with PKU at the age of 4 years and given treatment. His IQ was 97 at 26 years of age and moderate involvement of periventricular white matter was detected. The younger brother was diagnosed with PKU at the age of 11 months and given treatment. His IQ was < 25 at 22 years of age and severe dysmyelination changes were found by magnetic resonance imaging. The differences in the courses of the disease between these two brothers appear to be related to variations in their blood-brain barriers.

Grafting of isolated allogeneic keratocytes in the treatment of experimental defects in the rabbit cornea.

Keratocytes isolated by enzymatic digestion from the rabbit cornea propria were suspended in rabbit plasma clot and then transplanted into deep, experimental defects of the allogeneic recipients cornea. This procedure resulted in improved healing and transparency of the cornea observed up to two years after operation.