Point-cloud registration using adaptive radial basis functions

Non-rigid registration is a common part of bioengineering model-generation workflows. Compared to common mesh-based methods, radial basis functions can provide more flexible deformation fields due to their meshless nature. We introduce an implementation of RBF non-rigid registration with iterative knot-placement to adaptively reduce registration error. The implementation is validated on surface meshes of the femur, hemi-pelvis, mandible, and lumbar spine. Mean registration surface errors ranged from 0.37 to 0.99?mm, Hausdorff distance from 1.84 to 2.47?mm, and DICE coefficients from 0.97 to 0.99. The implementation is available for use in the free and open-source GIAS2 library.     

Fishers' knowledge and seahorse conservation in Brazil

From a conservationist perspective, seahorses are threatened fishes. Concomitantly, from a socioeconomic perspective, they represent a source of income to many fishing communities in developing countries. An integration between these two views requires, among other things, the recognition that seahorse fishers have knowledge and abilities that can assist the implementation of conservation strategies and of management plans for seahorses and their habitats. This paper documents the knowledge held by Brazilian fishers on the biology and ecology of the longsnout seahorse Hippocampus reidi. Its aims were to explore collaborative approaches to seahorse conservation and management in Brazil; to assess fishers' perception of seahorse biology and ecology, in the context evaluating potential management options; to increase fishers' involvement with seahorse conservation in Brazil. Data were obtained through questionnaires and interviews made during field surveys conducted in fishing villages located in the States of Piauí, Ceará, Paraíba, Maranhão, Pernambuco and Pará. We consider the following aspects as positive for the conservation of seahorses and their habitats in Brazil: fishers were willing to dialogue with researchers; although captures and/or trade of brooding seahorses occurred, most interviewees recognized the importance of reproduction to the maintenance of seahorses in the wild (and therefore of their source of income), and expressed concern over population declines; fishers associated the presence of a ventral pouch with reproduction in seahorses (regardless of them knowing which sex bears the pouch), and this may facilitate the construction of collaborative management options designed to eliminate captures of brooding specimens; fishers recognized microhabitats of importance to the maintenance of seahorse wild populations; fishers who kept seahorses in captivity tended to recognize the condtions as poor, and as being a cause of seahorse mortality.     

Science – A life fully lived: Joe Sodroski wins the 2006 Retrovirology Prize

The 2006 M Jeang Retrovirology Prize for HIV research has been awarded to Dr Joe Sodroski     

A rapid chemical spot test for the detection of lactic acid as an indicator of microbial spoilage in preserved foods

A ckland , M.R. & R eeder , J.E. 1984. A rapid chemical spot test for the detection of lactic acid as an indicator of microbial spoilage in preserved foods. Journal of Applied Bacteriology 56 , 415–419.
A rapid method for the detection of lactic acid in preserved foods has been developed, based upon a chemical spot test which does not require solvent extraction or derivatisation of the lactic acid in the sample. The test can be completed within 5 min and was shown to confirm microbial spoilage detected by cultural techniques in a range of preserved foods. In addition the test was able to indicate microbial spoilage in samples where cultural techniques failed because the spoilage organisms were dead. The test may not be appropriate for products which have a naturally high lactic acid content.     

Studies on the mechanism of zinc uptake by human fibroblasts

The mechanisms of zinc uptake from a complete culture medium by human fibroblasts have been studied. The metal is accumulated in a biphasic pattern; an initial rapid phase followed by a slower linear phase. We suggest that the former represents binding to carriers or receptors on the cell surface followed by uptake to within the cell, or at least to a compartment inaccessible to proteolytic digestion. The uptake correlates well with estimates of the zinc requirement of a growing fibroblast. The process of uptake is saturable, with an apparent association constant of 1.1 X 10(7) M-1. Interestingly, there appears to be a very large number of binding sites, 2 X 10(7) per cell. No explanation for this observation is immediately apparent. The mechanism of uptake is not dependent on metabolic energy, or at least on ATP levels within the cell, but N-ethyl maleimide does block uptake in a dose-dependent manner. Weak bases and ionophores, apart from nigericin, do not affect uptake. The results suggest that zinc is not taken up by a receptor-mediated endocytic pathway as has been described for transferrin and iron.     

Cation-dependent uptake of zinc in human fibroblasts

The influence of K⁺ and Ca²⁺ on Zn²⁺ transport into cultured human fibroblasts was investigated. Zn²⁺ uptake was markedly reduced in the presence of both valinomycin and nigericin (electrogenic and electroneutral K ⁺ ionophores, respectively), and by reduction in the transmembrane K⁺ gradient produced by replacement of extracellular K⁺ with Na⁺, suggesting that Zn²⁺ may be driven by a Zn²⁺/K⁺ counter-transport system. To test the counter-transport hypothesis, we used ⁸⁶Rb as an analog of K ⁺ for efflux studies. The rate of Rb⁺ efflux was 3760 times that of Zn²⁺ uptake, thus the component of K⁺ involved in the Zn²⁺ counter-transport system was only a small proportion of the total K⁺ efflux. In investigating the effect of Ca²⁺ on Zn²⁺ uptake, we identified two components: (1) a basal Zn²⁺ uptake pathway, independent of hormonal or growth factors which does not require extracellular Ca²⁺ and (2) a Ca²⁺-dependent mechanism. The absence of Ca²⁺ decreased Zn²⁺ uptake, while increasing extracellular C+a²⁺ stimulated Zn²⁺ uptake. The effect was mediated by Ca²⁺ influx as the ionophores A23187 and ionomycin also stimulated Zn²⁺ uptake. We could not ascribe the Ca²⁺ effect to known Ca²⁺ influx pathways. We conclude that Zn²⁺ uptake occurs by a K⁺-dependent process, possibly by Zn²⁺/K⁺ counter-transport and that a component of this is also Ca²⁺-dependent.