Polymorphisms in the leptin gene promoter in Brazilian beef herds.

Brazil is the world's largest producer of beef cattle; however, the quality of its herds needs to be improved. The use of molecular markers as auxiliary tools in selecting animals for reproduction with high pattern for beef production would significantly improve the quality of the final beef product in Brazil. The leptin gene has been demonstrated to be an excellent candidate gene for bovine breeding. The objective of this study was to sequence and compare the leptin gene promoter of Brazil's important cattle breeds in order to identify polymorphisms in it. Blood samples of the Nellore, Guzerat, Tabapuã, and Senepol breeds were collected for genomic DNA extraction. The genomic DNA was used as a template for polymerase chain reaction (PCR) to amplify a 1575-bp fragment, which in turn was sequenced, aligned, and compared between animals of different breeds. Twenty-three single nucleotide polymorphic sites, including transitions and transversions, were detected at positions -1457, -1452, -1446, -1397, -1392, -1361, -1238, -963,-901, -578, -516, -483, -478, -470, -432, -430, -292, -282, -272, -211, -202, -170, and -147. Additionally, two insertion sites at positions -680 and -416 and two deletion sites at positions -1255 and -1059 were detected. As the promoter region of the leptin gene has been demonstrated to vary among breeds, these variations must be tested for their use as potential molecular markers for artificial selection of animals for enhanced beef production in different systems of bovine production in Brazil.

Neonatal detection of Turner syndrome by real-time PCR gene quantification of the ARSE and MAGEH1 genes.

Turner syndrome (TS) is characterized by the presence of one full X chromosome and total or partial deletion of the second sex chromosome. Diagnosis of TS is often delayed, resulting in inappropriate treatment. Early diagnosis of TS using a neonatal screening test may improve preventive measures and treatment, thus improving patient quality of life. The goal of this study was to standardize a neonatal TS screening algorithm. Two study genes (ARSE and MAGEH1) and 1 normalizing gene (HBB) were used to detect the second X chromosome. We screened 996 newborns whose peripheral blood was collected and stored in filter paper. In addition, samples from 20 patients with confirmed diagnosis of TS were included in the study. Relative amounts of ARSE/HBB were determined using real-time polymerase chain reaction. The cutoff at the 5th percentile was arbitrarily set to indicate repetition of the test. The test was repeated in 51/1016 patients with ARSE/HBB < 0.81. For 10 samples with values persistently <0.81, we quantified the MAGEH1/HBB ratio. Values below the 95th percentile in TS patients (MAGEH1/HBB < 1.24) were considered to be inadequate. Only 6/996 NB showed inadequate values for the 2 studied genes, which were recalled for clinical evaluation and karyotype testing. Analysis of 20 patients diagnosed with TS allowed for identification of false-negatives and true-positives, establishing 95% sensitivity when the indicated cutoff values were used. In conclusion, our algorithm reached 95% detection sensitivity with an acceptable recall rate (0.6%), allowing for the detection of suspected TS cases in the neonatal period.

Computed radiography simulation using the Monte Carlo code MCNPX.

Simulating X-ray images has been of great interest in recent years as it makes possible an analysis of how X-ray images are affected owing to relevant operating parameters. In this paper, a procedure for simulating computed radiographic images using the Monte Carlo code MCNPX is proposed. The sensitivity curve of the BaFBr image plate detector as well as the characteristic noise of a 16-bit computed radiography system were considered during the methodology's development. The results obtained confirm that the proposed procedure for simulating computed radiographic images is satisfactory, as it allows obtaining results comparable with experimental data.

Assessment of weld thickness loss in offshore pipelines using computed radiography and computational modeling.

In order to guarantee the structural integrity of oil plants it is crucial to monitor the amount of weld thickness loss in offshore pipelines. However, in spite of its relevance, this parameter is very difficult to determine, due to both the large diameter of most pipes and the complexity of the multi-variable system involved. In this study, a computational modeling based on Monte Carlo MCNPX code is combined with computed radiography to estimate the weld thickness loss in large-diameter offshore pipelines. Results show that computational modeling is a powerful tool to estimate intensity variations in radiographic images generated by weld thickness variations, and it can be combined with computed radiography to assess weld thickness loss in offshore and subsea pipelines.

Dose-image quality study in digital chest radiography using Monte Carlo simulation.

One of the main preoccupations of diagnostic radiology is to guarantee a good image-sparing dose to the patient. In the present study, Monte Carlo simulations, with MCNPX code, coupled with an adult voxel female model (FAX) were performed to investigate how image quality and dose in digital chest radiography vary with tube voltage (80-150 kV) using air-gap technique and a computed radiography system. Calculated quantities were normalized to a fixed value of entrance skin exposure (ESE) of 0.0136 R. The results of the present analysis show that the image quality for chest radiography with imaging plate is improved and the dose reduced at lower tube voltage.

Methodology for digital radiography simulation using the Monte Carlo code MCNPX for industrial applications.

This work presents a methodology for digital radiography simulation for industrial applications using the MCNPX radiography tally. In order to perform the simulation, the energy-dependent response of a BaFBr imaging plate detector was modeled and introduced in the MCNPX radiography tally input. In addition, a post-processing program was used to convert the MCNPX radiography tally output into 16-bit digital images. Simulated and experimental images of a steel pipe containing corrosion alveoli and stress corrosion cracking were compared, and the results showed good agreement between both images.