Electrically conductive and high temperature resistant superhydrophobic composite films from colloidal graphite

Electrically conductive and self-cleaning superhydrophobic films (water contact angles >160°, droplet roll off angles <5°) were fabricated by simply solution casting sub-micron polytetrafluoroethylene (Teflon) particle dispersed alcohol-based colloidal graphite solutions. The process is very suitable for forming conductive superhydrophobic coatings on glasses, metals, ceramics and high performance polymers such as polyimide (Kapton®). The solutions were deposited on microscope glass slides and Kapton® films by drop casting. After solvent evaporation under ambient conditions, the coatings were annealed to melt Teflon. Upon melting, Teflon particles fused into one another forming a hydrophobic polymer matrix. The degree of superhydrophobicity and the surface morphology of the coatings together with their electrical conductivity were studied in detail by varying Teflon-to-graphite weight fractions. A number of applications can be envisioned for these coatings such as electrode materials for energy conversion devices, high performance electromagnetic shielding materials, flexible electronic components and heat exchanger surfaces, to name a few

Dental enamel, fluorosis and amoxicillin

Introduction: Amoxicillin is one of the most used antibiotics among pediatric patients for the treatment of upper respiratory tract infections and specially for acute otitis media (AOM), a common diseases of infants and childhood. It has been speculated that the use of amoxicillin during early childhood could be associated with dental enamel fluorosis, also described in literature with the term Molar Incisor Hypomineralization (MIH), because they are generally situated in one or more 1st permanent molars and less frequently in the incisors. The effect of Amoxicillin seems to be independent of other risk factors such as fluoride intake, prematurity, hypoxia, hypocalcaemia, exposure to dioxins, chikenpox, otitis media, high fever and could have a significant impact on oral health for the wide use of this drug in that period of life. Objective: The aim of this work was to review the current literature about the association between amoxicillin and fluorosis. Methods and Results: A literature survey was done by applying the Medline database (Entrez PubMed); the Cochrane Library database of the Cochrane Collaboration (CENTRAL). The databases were searched using the following strategy and keywords: amoxicillin* AND (dental fluorosis* OR dental enamel*) AND MIH*. After selecting the studies, only three relevant articles published between 1966 and 2011 were included in the review. Conclusion: The presence of several methodological issues does not allow to draw any evidence-based conclusions. No evidence of association was detected, therefore, there is a need of further well-designed studies to assess the scientific evidence of the relationship between amoxicillin and fluorosis and to restrict the prescription of this drug for recurrent upper respiratory tract infections especially acute otitis media (AOM) during the first two years of life. When it is possible can be opportune to use an alternative antibiotic treatment

Ownership and control in a competitive industry

We study a differentiated product market in which an investor initially owns a controlling stake in one of two competing firms and may acquire a non-controlling or a controlling stake in a competitor, either directly using her own assets, or indirectly via the controlled firm. While industry profits are maximized within a symmetric two product monopoly, the investor attains this only in exceptional cases. Instead, she sometimes acquires a noncontrolling stake. Or she invests asymmetrically rather than pursuing a full takeover if she acquires a controlling one. Generally, she invests indirectly if she only wants to affect the product market outcome, and directly if acquiring shares is profitable per se. --differentiated products,separation of ownership and control,private benefits of control

FUNCTIONAL MR OF BRAIN ACTIVITY AND PERFUSION IN PATIENTS WITH CHRONIC CORTICAL STROKE

PURPOSE: (1) To determine whether functional MR can reliably map functional deficits in patients with stroke in the primary visual cortex; (2) to determine whether functional MR can reliably map perfusion deficits; and (3) to determine whether functional MR can give any additional diagnostic information beyond conventional MR. METHODS: Seven patients who had had a stroke in their primary visual system were examined using two functional MR techniques: (1) dynamic susceptibility contrast imaging, and (2) cortical activation mapping during full-field visual stimulation. Maps of relative cerebral blood volume and activation were created and compared with visual field examinations and conventional T2-weighted images on a quadrant-by-quadrant basis in five of these patients. RESULTS: Visual field mapping matched with both T2-weighted conventional images and activation mapping of 16 of 18 quadrants. In two quadrants, the activation maps detected abnormalities that were present on the visual field examination but not present on the T2-weighted images nor on the relative cerebral blood volume maps, which may indicate abnormal function without frank infarction. In addition, the activation maps demonstrated decreased activation in extrastriate cortex and had normal T2 signal and relative cerebral blood volume but was adjacent to infarcted primary cortex, mapping in vivo how stroke in one location can affect the function of distant tissue. CONCLUSION: Functional MR techniques can accurately map functional and perfusion deficits and thereby provide additional clinically useful information. Additional studies will be needed to determine the prognostic utility of functional MR in stroke patients