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Numerical values of lattice star entropic exponents Îł f , and star vertex exponents σ f , are estimated using parallel implementations of the PERM and Wangâ€"Landau algorithms. Our results show that the numerical estimates of the vertex exponents deviate from predictions of the ϵ -expansion and confirms and improves on estimates in the literature. We also estimate the entropic exponents Îł G of a few acyclic branched lattice networks with comb and brush connectivities. In particular, we confirm within numerical accuracy the Duplantier scaling relation Îł G âˆ' 1 = âˆ' f â©ľ 1 m f σ f for a comb and two brushes (where m f is the number of nodes of degree f in the network) using our independent estimates of σ f . [ABSTRACT FROM AUTHOR]

BACKGROUND: High-risk human papilloma viruses (HPV) are reported to be significant independent risk factors for oral squamous cell carcinoma (OSCC). The prevalence of HPV in OSCC in a South African population sample was evaluated comparing three different HPV detection methods. METHODS: Tumour and adjacent morphologically normal oral mucosa of 59 resections of primary OSCC were evaluated for the presence of HPV using real-time polymerase chain reaction (PCR), conventional in situ hybridization (ISH), and a signal amplification ISH technique (Dako GenPoint). RESULTS: HPV18 DNA was detected in seven cases using real-time PCR. No positivity was found with the other two ISH techniques. CONCLUSIONS: We support the view that HPV is probably unimportant in the pathogenesis of OSCC and hypothesize HPV detection techniques as the main reason for the positive results in many studies. Real-time PCR was confirmed as the most sensitive technique, but researchers are urged to incorporate strict internal controls when using this detection method. [ABSTRACT FROM AUTHOR]