p53 antibodies in the saliva of patients with squamous cell carcinoma of the oral cavity

A significant age dependence of the risk of complete heart block complicating radiofrequency ablation of the AV nodal slow pathway was noticed, with no patients <45 years of age experiencing this complication.     

Molecular genetic diagnosis of von Hippel-Lindau disease in familial phaeochromocytoma

Inherited predisposition to phaeochromocytoma is seen in multiple endocrine neoplasia type 2 syndromes, von Hippel-Lindau (VHL) disease, and neuro-fibromatosis type 1. In addition familial phaeochromocytoma alone has been reported. To investigate the genetic basis for familial phaeochromocytoma alone, we screened three affected kindreds for mutations in the RET proto-oncogene and the VHL tumour suppressor gene. We did not detect MEN 2 associated RET mutations in any family, but missense VHL gene mutations (V155L and R238W) were identified in two kindreds with no clinical evidence of VHL disease. Patients with familial, multiple, or early onset phaeochromocytoma should be investigated for germline VHL and RET gene mutations as the molecular diagnosis of multisystem familial cancer syndromes enables appropriate counselling and screening to be provided.     

The influence of trend on estimates of accidents at junctions

While reliable estimates of expected accidents can be achieved by combining observed accidents and accident model predictions using an empirical Bayes approach, there are a number of obstacles to the widespread adoption of the method. This paper concentrates on problems associated with the available predictive models. Of particular concern is the effect on model predictions of accident trends over time resulting from, for instance, traffic growth or national road safety programmes. Since accident models invariably include traffic flow as an explanatory variable, the effects of flow changes can be included provided that account is taken of the nonlinear relationship between accidents and exposure. It is, however, common to assume that accident risk per unit of exposure is constant over time, whereas national data imply that accident risk is declining. In addition, there is a need, in practice, to rank and evaluate remedial sites in terms of the specific accident types or severities which might be targeted by treatment (for example, wet road accidents in the case of surface treatment). This then raises the question of whether the proportions of accidents of various types varies over time or with traffic flow and site characteristics. Generalized linear modelling was used to develop regression estimates of expected junction accidents (both in total and disaggregated by severity, road surface condition and lighting condition) which allow for the possibility of accident risk varying over time. Accident risk at the sample of some 500 junctions was shown to be declining annually by an average of 6%, with no significant difference in the value of trend between accident types. The factors which affected the proportions of accidents of various types included the method of junction control, speed limit and traffic flow.     

Rapid detection of Listeria monocytogenes in food using culture enrichment combined with real-time PCR

A rapid method for the detection of Listeria monocytogenes in foods combining culture enrichment and real-time PCR was compared to the ISO 11290-1 standard method. The culture enrichment component of the rapid method is based on the ISO standard and includes 24 h incubation in half-Fraser broth, 4 h incubation in Fraser broth followed by DNA extraction and real-time PCR detection of the ssrA gene of L. monocytogenes. An internal amplification control, which is co-amplified with the same primers as the L. monocytogenes DNA, was also included in the assay. The method has a limit of detection of 1–5 CFU/25 g food sample and can be performed in 2 working days compared to up to 7 days for the ISO standard. A variety of food samples from retail outlets and food processing plants (n = 175) and controls (n = 31) were tested using rapid and conventional methods. The rapid method was 99.44% specific, 96.15% sensitive and 99.03% accurate when compared to the standard method. This method has the potential to be used as an alternative to the standard method for food quality assurance providing rapid detection of L. monocytogenes in food.     

Finite element method applied to the supersonic flutter of circular cylindrical shells

The application of the finite element method to the supersonic flutter of circular cylindrical shells subjected to internal pressure and axial compression is presented. A circular cylindrical shell element is used. The element stiffness, mass and initial stiffness matrices are given. The element aerodynamic matrix is derived based on a first order high Mach number approximation to the linear potential flow theory. The eigenvalue problem is solved by the QR algorithm. Numerical results are presented and these are compared with analytical solutions and experimental data.     

Topographical contrast in the transmission electron microscope

An adaptation of the Foucault method for topographical imaging in the transmission electron microscope is described in detail. The image contrast is produced by selection of electrons which have suffered differential phase retardations in the specimen inner potential. Surface or interface displacements produce bright or dark image contrast, and the ultimate resolution approaches that of the atomic scale. The imaging method is applied in studies of both amorphous and crystalline objects. The possibility of performing quantitative measurements is demonstrated by the estimation of the inner potential of crystalline MgO.     

Dielectric relaxation of monoesters based poly(styrene-co-maleic anhydride) copolymer

A series of alkyl-grafted copolymers based on styrene-maleic anhydride (SMA) copolymers were synthesized by esterification of SMA with several long chain normal aliphatic alcohols. The prepared copolymers were characterized by FT-IR and ¹H NMR and DSC. The dielectric behavior of these copolymers was investigated in the frequency 20–10⁵ Hz and temperature −40 to 180 °C ranges. Two relaxation processes were observed, α, and β-relaxation. The former is associated with the glass-rubber transition and is characterized by the Vogel–Fulcher–Tammann temperature dependence and the latter relaxation is related to the local motion of the ester side groups attached to the polymer backbone. The apparent activation energy for the β-relaxation was found to depend significantly on the alkyl chain length. The dielectric analysis of the β-relaxation process detected is discussed.     

Modelling of proton exchange membrane fuel cell performance based on semi-empirical equations

Using semi-empirical equations for modeling a proton exchange membrane fuel cell is proposed for providing a tool for the design and analysis of fuel cell total systems. The focus of this study is to derive an empirical model including process variations to estimate the performance of fuel cell without extensive calculations. The model take into account not only the current density but also the process variations, such as the gas pressure, temperature, humidity, and utilization to cover operating processes, which are important factors in determining the real performance of fuel cell. The modelling results are compared well with known experimental results. The comparison shows good agreements between the modeling results and the experimental data. The model can be used to investigate the influence of process variables for design optimization of fuel cells, stacks, and complete fuel cell power system.