RESUMO
Lung cancer is the most common cancer worldwide. Survivin is one of the first reported inhibitors of apoptosis proteins, which is an important family of proteins that regulate apoptosis. The survivin gene is located on human chromosome 17q25, which is composed of 142 amino acids. A common polymorphism of the survivin gene promoter -31G/C has been shown to influence cancer risk. This genetic variant has been associated with overexpression of survivin at both protein and mRNA levels in cancer cells. We examined promoter (-31G/C) genotype frequency in a patient group (N = 146), 77.4% GG, 18.5% GC, 4.1% CC, and in a control group (N = 98), 57.1% GG, 34.7% GC, 8.2% CC. These distributions were significantly different. Promoter (-644C/T) genotype frequency in the patient group was 40.4% TT, 48.6% TC, 11% CC, and in the control group it was 55.1% TT, 40.8% TC, 4.1% CC; these distributions were also significantly different. Individuals carrying the survivin 31 GC genotype and those carrying the survivin 644 CC genotype had a significantly decreased risk of having non-small cell lung cancer.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Proteínas Inibidoras de Apoptose/genética , Polimorfismo Genético , Regiões Promotoras Genéticas , Estudos de Casos e Controles , Cromossomos Humanos Par 17/genética , Frequência do Gene , Predisposição Genética para Doença , Genética Populacional , Genótipo , Humanos , Modelos Logísticos , Análise Multivariada , Prognóstico , Survivina , TurquiaRESUMO
PURPOSE: Wide spread clinical use of advanced radiation treatment delivery techniques such as volumetric modulated arc therapy (VMAT) and IMRT needs an easy-to-use, well-defined, and effective quality assurance (QA) system to ensure the accuracy of dose delivery. The comprehensive evaluation of two delivery QA systems (DQA) (Portal Dosimetry and Compass) for the advanced radiation delivery techniques is necessary for the clinical setting. METHODS: Portal Dosimetry QA system with Varian PortalVision (PV) provides a quantitative comparison of measured electronic dose profile to a predicted dose profile with Varian's Eclipse™ treatment planning system (TPS) for the VMAT and IMRT plans. Quantitative comparisons of the two images, including dose difference, gamma analysis, points dose measurements, and line profiles are easily acquired in two dimensions. Meanwhile, Compass system with MatriXX can provide an accurate three-dimensional quantitative analysis of dose delivery. We applied the two planning QA systems to our RapidArc patient- specific QAs. Validation of the Compass and Portal Dosimetry systems were performed with ionization chamber measurements for absolute dosimetry and film measurements for gamma index calculations for phantom and patient treatment plans. RESULTS: Compass system was very sensitive to the MLC leaf gap variations in three dimensional gamma analyses. However, Compass system was not enough to fix the errors in dosimetric leaf gap by itself. DQA process with Portal Dosimetry took approximately 6 minutes for the two Arcs VMAT plan. Compass took about 40 minutes for the same plan in our first clinical trial. For the three typical IMRT and VMAT plans, the two systems showed the same passing rates in 95% pixels passing gamma criteria 3%/3mm. CONCLUSIONS: Portal Dosimetry DQA system has the advantages of effectiveness and practicality in the clinical setting. On the other hand, Compass was the next supportive system because of its accuracy and reality with patient's anatomy.
RESUMO
Molecular dynamics simulations were performed for soft- and hard-sphere systems, for number densities ranging from 0.5 to 1.0, and the Kolmogorov-Sinai entropy (KS entropy) and self-diffusion coefficients were calculated. It is found that the KS entropy, when expressed in terms of average collision frequency, is uniquely related to the self-diffusion coefficient by a simple scaling law. The dependence of the KS entropy on average collision frequency and number density was also explored. Numerical results show that the scaling laws proposed by Dzugutov, and by Beijeren, Dorfman, Posch, and Dellago, can be applied to both soft- and hard-sphere systems by changing to more generalized forms.
