Patient-Specific Unicompartmental Knee Resurfacing Arthroplasty: Use of a Novel Interference Lock to Reduce Tibial Insert Micromotion and Backside Wear

Micromotion has long been associated with wear of polyethylene tibial inserts, potentially causing failure of unicompartmental knee replacement systems. One cause of micromotion is the locking mechanism between the undersurface of the polyethylene and the tibial tray. The objective of this study was to investigate the use of new novel lock designs for reducing the micromotion associated with a patient specific tibial implant. Micromotion occurring between the tibial insert and tibial tray was measured using the DVRT method for two new lock designs and compared to the micromotion measured for the prior generation lock design. In total, 18 samples were tested, six in each of the three designs: prior generation CLEARANCE lock design, new LINE-TO-LINE design, new INTERFERENCE design

Simple does not mean poor: grasslands and forests harbor similar ant species richness and distinct composition in highlands of southern Brazil

Several studies addressed ant communities in the dense Atlantic Forest that runs along the Brazilian coast. However, comparatively little is known about the mixed forests and grasslands that occur in the southern range of the Atlantic Forest domain. In this study we performed the first standardized assessment of ants in the forest- grassland mosaic found in the highlands of the state of Santa Catarina. We aimed to investigate and compare ant richness and composition between mixed forests and grasslands in the main mountain range of south Brazil. Ants were collected in two years with ground pitfalls, tree pitfalls and litter samples. Sixty ant species were recorded, resulting in 22 new records for “Planalto Serrano” region and three for the state of Santa Catarina: Eurhopalothrix depressa , Pheidole radoszkowskii and Wasmannia williamsoni . There was significant dissimilarity in ant species composition between grasslands and forests, but no difference in ant species richness, even considering the higher number of strata in mixed forests. Similar richness and low number of arboreal species suggest that this ant community is structured similarly to temperate ones. Both habitats presented a large proportion of exclusive species. The fact that species composition between grassland and forest areas differed, coupled with the similarity in species richness between habitats and the record of new ant species for the region, calls for strong conservation efforts in grasslands of southern Brazil, which still are little protected by conservation areas

Cytogenetic analysis on Pterophyllum scalare

Cytogenetic studies were carried out on eighteen wild specimens of Pterophyllum scalare from Jari River, in Pará state, and the results were compared to literature. Mitotic chromosomes were obtained from kidney cells and the analysis was done using: C-banding, Ag-NOR staining, Chromomycin A3/DAPI sequential staining and fluorochrome in situ hybridization with human telomere probes. All individuals showed a chromosome number of 2n = 48 (12 M/SM and 36 ST/A) and FN = 60. No differences were detected between male and female karyotypes, indicating the absence of morphologically differentiated mitotic sexual chromosomes. Constitutive heterochromatin blocks were located at the centromeric and pericentromeric regions of all chromosomes. The largest submetacentric pair showed a differential staining on their short arms. Only two NOR bearing chromosomes were detected, and the stainings were observed at the distal region of the short arm of the largest chromosome pair, matching the secondary constriction. Chromomycin A3, stained the NOR and the centromeres of some chromosomes. DAPI-bands were observed at the centromeric regions of all chromosomes. Telomere sequences hybridised only at the terminal regions. © 2006 Taylor and Francis Group, LLC

On waiting time distributions associated with compound patterns in a sequence of multi-state trials

Compound pattern, Scan, Run, Multi-state trials, Enumeration schemes, Conditional distribution, Probability function, Probability generating function, Double generating function,