Kurian Mathew Abraham

Publications (3) View all

• Article: Comparative evaluation of frictional forces in active and passive self-ligating brackets with various archwire alloys.

  Manu Krishnan, Sukumaran Kalathil, Kurian Mathew Abraham
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  ABSTRACT: Self-ligating brackets are claimed to eliminate or minimize the force of ligation at the bracket-wire interface; therefore, it is imperative to evaluate the frictional features of contemporary self-ligating brackets with different archwire alloys. This in-vitro study compared the effects of stainless steel, nickel-titanium, and beta-titanium archwires on frictional forces of passive and active self-ligating brackets with a conventional bracket. All brackets had 0.022-in slots, and the wires were 0.019 x 0.025 in. Friction was evaluated in a simulated half-arch fixed appliance on a testing machine. The static and kinetic friction data were analyzed with 1-way analysis of variance (ANOVA) and the post-hoc Duncan multiple range test. Archwire alloy and bracket effects were evaluated with 2-way ANOVA. Static and kinetic frictional forces were lower for both the passive and active designs than for the conventional brackets. Maximum values were seen with the beta-titanium archwires, and significant differences were observed between nickel-titanium and stainless steel archwires. With the passive or active self-ligating brackets, stainless steel wire did not produce a significant difference, but differences were significant with nickel-titanium and beta-titanium wires. When nickel-titanium and beta-titanium wires are used for guided tooth movement, passive appliances can minimize frictional resistance.
  American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics 11/2009; 136(5):675-82. · 1.33 Impact Factor
• Article: Study on the gill of field crab, Paratelphusa hydrodromus (Herbst.) exposed to nickel.

  Kurian Mathew Abraham, Tresa Radhakrishnan
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  ABSTRACT: Paratelphusa hydrodromus (Herbst.) was exposed to 50 ppm nickel chloride solution for a period of 10 days under laboratory conditions. The gills of the treated and non-treated animals were sectioned, stained and examined under a compound microscope and noticed significant changes such as enlargement of gill lamellae, lifting up and rupture of epithelial cells, enlargement of mid rachis, hyperplasia and hypertrophy, appearance of pyknotic nuclei and a general necrosis in the treated gills. Results suggest that a comparatively low concentration of nickel (50 ppm) is enough to elicit pathological changes in Paratelphusa hydrodromus.
  Journal of Environmental Biology 05/2002; 23(2):151-5. · 0.64 Impact Factor
• Article: Morphometry and meristics of longnose seahorse, Hippocampus trimaculatus (Actinopterygii: Syngnathidae), from Kerala, south-west coast of India

  Appukuttannair Bijukumar, Kurian M. Abraham, Devarajan Soumya
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  ABSTRACT: Background. The longnose seahorse, Hippocampus trimaculatus Leach, 1814, included in the Red List of Threatened Species is the most common and least studied seahorse species along the south-west coast of India. Practically no information is available on numerical taxonomy and sexual dimorphism of H. trimaculatus from India. The purpose of the reported study is to describe the morphometry and meristics of H. trimaculatus occurring along Kerala, south-west coast of India.Materials and Methods. A total of 45 specimens of H. trimaculatus, represented by 25 males and 20 females, obtained from trawl by-catch, were studied following standard morphometric and meristics procedures. Statistical data analyses include Student's t-test, Mann-Whitney U test, and Principal Component Analysis to describe the sexual dimorphism of the species.Results. Male H. trimaculatus are longer than females, with relatively longer tails. The mean values of head depth, snout depth, trunk depth, trunk width, dorsal fin base length, and pectoral fin base length are higher in males, while head length, snout length, coronet height, and trunk length are higher in females. Trunk length and snout depth are the two principal components that determine sexual dimorphism in H. trimaculatus.Conclusion. The numerical taxonomy of H. trimaculatus from Indian coastal waters is reported for the first time. The study shows that sexual dimorphism in H. trimaculatus is reflected in differing morphometric characters between the sexes.
  Acta Ichthyologica Et Piscatoria 11/2008; 38(2):149-155. · 0.55 Impact Factor