Corneal stromal demarcation line after collagen cross-linking in corneal ectatic diseases: a review of the literature

Collagen cross-linking (CXL) is a relatively new conservative approach for progressive corneal ectasia, which is able to strengthen corneal tissue reforming new covalent bonds. Subjective and objective results following this method seem to be promising. In recent years, newer CXL protocols have been developed to perform more effective and less invasive procedures. The increasing diffusion of CXL in the corneal ectatic disease has increased the need to have actual indices regarding the efficacy of the treatment. Evaluation of demarcation line (DL), a transition zone between the cross-linked anterior corneal stroma and the untreated posterior corneal stroma, is considered a measurement of the depth of CXL treatment into the stroma. Some evidence in the literature emphasize that DL could be a measure of effectiveness of the CXL. On the contrary, some authors believe that the "the deeper, the better" principle is rather a simplistic approach for interpreting the clinical importance of the corneal stromal DL

Single-file escape of colloidal particles from microfluidic channels

Single-file diffusion is a ubiquitous physical process exploited by living and synthetic systems to exchange molecules with their environment. It is paramount quantifying the escape time needed for single files of particles to exit from constraining synthetic channels and biological pores. This quantity depends on complex cooperative effects, whose predominance can only be established through a strict comparison between theory and experiments. By using colloidal particles, optical manipulation, microfluidics, digital microscopy and theoretical analysis we uncover the self-similar character of the escape process and provide closed-formula evaluations of the escape time. We find that the escape time scales inversely with the diffusion coefficient of the last particle to leave the channel. Importantly, we find that at the investigated {\bf microscale}, bias forces as tiny as $10^{-15}\;{\rm N}$ determine the magnitude of the escape time by drastically reducing interparticle collisions. Our findings provide crucial guidelines to optimize the design of micro- and nano-devices for a variety of applications including drug delivery, particle filtering and transport in geometrical constrictions.Comment: 6 pages, 3 figure

Hamiltonian structure and stability analysis of a reduced four-field model for plasmas in the presence of a strong guide field

International audienceWe analyze the collisionless and inviscid limit of a reduced fluid model for tokamak plasma dynamics. We show that the model under consideration possesses a noncanonical Hamiltonian structure with four infinite families of Casimir invariants. Sufficient conditions for energy stability are derived and formulated in terms of requirements on the current, electron pressure, and parallel ion velocity gradients, as well as on the ion temperature. In particular, the stability condition requires a gradient of the parallel flow in the presence of ion temperature and a negative upper bound on the current gradient, in the presence of pressure gradients and/or parallel velocity gradients. Examples of stable configurations are derived

Resurgent Current and Voltage Sensor Trapping Enhanced Activation by a β-Scorpion Toxin Solely in Nav1.6 Channel SIGNIFICANCE IN MICE PURKINJE NEURONS

Abstract Resurgent currents are functionally crucial in sustaining the high frequency firing of cerebellar Purkinje neurons expressing Nav1.6 channels. β-Scorpion toxins, such as CssIV, induce a left shift in the voltage-dependent activation of Nav1.2 channels by "trapping" the IIS4 voltage sensor segment. We found that the dangerous Cn2 β-scorpion peptide induces both the left shift voltage-dependent activation and a transient resurgent current only in human Nav1.6 channels (among 1.1-1.7), whereas CssIV did not induce the resurgent current. Cn2 also produced both actions in mouse Purkinje cells. These findings suggest that only distinct β-toxins produce resurgent currents. We suggest that the novel and unique selectivity of Cn2 could make it a model drug to replace deep brain stimulation of the subthalamic nucleus in patients with Parkinson disease

Elevated urine levels of bufotenine in patients with autistic spectrum disorders and schizophrenia

Previous studies have suggested that the endogeneous psychotomimetic molecule bufotenine (N-N notdimethyl-5-idroxytryptamine) may play a role in the pathogenesis of severe mental disorders. The potential association of bufotenine with the clinical features of autism and schizophrenia is not entirely understood. In this study, we measured urinary levels of bufotenine in subjects with autistic spectrum disorder (ASD), schizophrenia and healthy comparison subjects free of psychiatric symptoms. We also sought to assess whether urine concentrations of this molecule may be associated with the clinical characteristics of psychiatric patients. DESIGN: Urine bufotenine levels were measured using a high-performance liquid chromatography-mass spectrometry (HPLC-MS) assay in young adults with severe ASD (n = 15), patients with schizophrenia (n = 15), and healthy control subjects (n = 18). The Vineland Adaptive Behavior Scale was used to measure adaptive behaviors in ASD individuals. The Brief Psychiatric Rating Scale (BPRS) was used for patients with schizophrenia. RESULTS: Urine bufotenine levels were significantly higher in ASD subjects (3.30 +/- 0.49 mug/L, P < 0.05) and patients with schizophrenia (4.39 +/- 0.43 mug/L, P < 0.001) compared with controls (1.53 +/- 0.30 mug/L). Among patients with ASD, there was a significant positive correlation between urine bufotenine and hyperactivity scores on the Vineland Adaptive Behavior Scale (r = 0.479, P < 0.05). No other associations were detected. CONCLUSIONS: our results indicate that elevated urine levels of the endogeneous psychotomimetic molecule bufotenine may play a role in ASD and schizophrenia, and can be correlated with hyperactivity scores in autism

Quelques Aspects du Role du Programme Tempus dans l'Internationalisation de l'Enseignement Supérior.

L’expérience de l’Institut Universitaire de Technologie (I. U. T.) de Béthune (Université d’Artois) dans le programme Tempus-Phare provient de son activité depuis le 1er septembre 1991 dans 17 projets différents générant un budget global d’environ 5 millions d’ECU