Ring electrode for radio-frequency heating of the cornea: modelling and in vitro experiments

[EN] Radio-frequency thermokeratoplasty (RF-TKP) is a technique used to reshape the cornea curvature by means of thermal lesions using radio-frequency currents. This curvature change allows refractive disorders such as hyperopia to be corrected. A new electrode with ring geometry is proposed for RF-TKP. It was designed to create a single thermal lesion with a full-circle shape. Finite element models were developed, and the temperature distributions in the cornea were analysed for different ring electrode characteristics. The computer results indicated that the maximum temperature in the cornea was located in the vicinity of the ring electrode outer perimeter, and that the lesions had a semi-torus shape. The results also indicated that the electrode thickness, electrode radius and electrode thermal conductivity had a significant influence on the temperature distributions. In addition, in vitro experiments were performed on rabbit eyes. At 5 IN power the lesions were fully circular. 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Psychological and social effects of orthodontic treatment

Adolescents with commonly occurring forms of malocclusion often are presumed to be at risk for negative self-esteem and social maladjustment. A randomized control group design was used to assess the psychosocial effects of orthodontic treatment for esthetic impairment. Ninety-three participants, 11 to 14 years old, with mild to moderate malocclusions, were randomly assigned to receive orthodontic treatment immediately or after serving as delayed controls. A battery of psychological and social measures was administered before treatment, during treatment, and three times after completion of treatment, the last occurring one year after termination. Repeated measures analyses of variance assessed group differences at the five time points. Parent-, peer-, and self-evaluations of dental-facial attractiveness significantly improved after treatment, but treatment did not affect parent- and self-reported social competency or social goals, nor subjects' self-esteem. In summary, dental-specific evaluations appear to be influenced by treatment, while more general psychosocial responses are not.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44814/1/10865_2005_Article_BF01856884.pd

A novel categorisation system to organise a large photo identification database for white sharks Carcharodon carcharias

The white shark Carcharodon carcharias was one of the first elasmobranch species where photo identification was used to identify unique individuals. In this study, we propose guidelines that improve the current photo identification technique for white sharks by presenting a novel categorisation system. Using this method, a high-resolution photograph of the dorsal fin is placed on a standardised three-section grid. Notches associated with the trailing edge of the fin are counted and scored within each grid section. The number of notches in each grid section is then used to produce a three-part code that is utilised to systematically organise the individuals into a database. Our proposed system was tested on sharks photographed in the sampling area over a 27-month period (4 398 photographs) and the method significantly reduced the search time associated with identifying resighted individuals. Using the notches code, we were able to identify 426 different C. carcharias within the Dyer Island Nature Reserve (South Africa). Due to the inherent ease of use, the accuracy associated with this method, and the ability to ‘resight’ individuals rapidly within a large photographic database, this non-invasive technique presents a validated and feasible alternative for future white shark photo identification studies.Keywords: dorsal fin, fingerprint, notches code, South AfricaAfrican Journal of Marine Science 2014, 36(1): 59–6