982 resultados para Advanced Encryption Standard
Resumo:
PURPOSE. Advanced glycation end products (AGES) form irreversible cross- links with many macromolecules and have been shown to accumulate in tissues at an accelerated rate in diabetes. In the present study, AGE formation in vitreous was examined in patients of various ages and in patients with diabetes. Ex vivo investigations were performed on bovine vitreous incubated in glucose to determine AGE formation and cross-linking of vitreous collagen. METHODS. By means of an AGE-specific enzyme-linked immunosorbent assay (ELISA), AGE formation was investigated in vitreous samples obtained after pars plana vitrectomy in patients with and without diabetes. In addition, vitreous AGES were investigated in bovine vitreous collagen after incubation in high glucose, high glucose with aminoguanidine, or normal saline for as long as 8 weeks. AGEs and AGE cross-linking was subsequently determined by quantitative and qualitative assays. RESULTS. There was a significant correlation between AGEs and increasing age in patients without diabetes (r = 0.74). Furthermore, a comparison between age-matched diabetic and nondiabetic vitreous showed a significantly higher level of AGEs in the patients with diabetes (P < 0.005). Collagen purified from bovine vitreous incubated in 0.5 M glucose showed an increase in AGE formation when observed in dot blot analysis, immunogold labeling, and AGE ELISA. Furthermore, there was increased cross-linking of collagen in the glucose-incubated vitreous, when observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein separation. This cross-linking was effectively inhibited by coincubation with 10 mM aminoguanidine. CONCLUSIONS. This study suggests that AGEs may form in vitreous with increasing age. This process seems to be accelerated in the presence of diabetes and as a consequence of exposure to high glucose. Advanced glycation and AGE cross-linking of the vitreous collagen network may help to explain the vitreous abnormalities characteristic of diabetes.
Resumo:
A new domain-specific, reconfigurable system-on-a-chip (SoC) architecture is proposed for video motion estimation. This has been designed to cover most of the common block-based video coding standards, including MPEG-2, MPEG-4, H.264, WMV-9 and AVS. The architecture exhibits simple control, high throughput and relatively low hardware cost when compared with existing circuits. It can also easily handle flexible search ranges without any increase in silicon area and can be configured prior to the start of the motion estimation process for a specific standard. The computational rates achieved make the circuit suitable for high-end video processing applications, such as HDTV. Silicon design studies indicate that circuits based on this approach incur only a relatively small penalty in terms of power dissipation and silicon area when compared with implementations for specific standards. Indeed, the cost/performance achieved exceeds that of existing but specific solutions and greatly exceeds that of general purpose field programmable gate array (FPGA) designs.
Resumo:
Background: Malignant mesothelioma (MM) is an aggressive disease that is diagnosed mostly in locally advanced or metastatic stage. In this condition chemotherapy with the combination cisplatin and pemetrexed or ralitrexed represents the standard treatment as supported by a phase III study. However, chemotherapy has very limited effect on the improvement of survival of patients and very few of the MM patients survive more than 2 years. A better understanding of molecular mechanisms and pathways involved in angiogenesis in MM is the basis for the development of new drugs targeted against these pathways responsible for the proliferation and survival of tumor cells.
Resumo:
Background: Breast cancer mortality is declining in many Western countries. If mammography screening contributed to decreases in mortality, then decreases in advanced breast cancer incidence should also be noticeable.
Patients and methods: We assessed incidence trends of advanced breast cancer in areas where mammography screening is practiced for at least 7 years with 60% minimum participation and where population-based registration of advanced breast cancer existed. Through a systematic Medline search, we identified relevant published data for Australia, Italy, Norway, Switzerland, The Netherlands, UK and the USA. Data from cancer registries in Northern Ireland, Scotland, the USA (Surveillance, Epidemiology and End Results (SEER), and Connecticut), and Tasmania (Australia) were available for the study. Criterion for advanced cancer was the tumour size, and if not available, spread to regional/distant sites.
Results: Age-adjusted annual percent changes (APCs) were stable or increasing in ten areas (APCs of -0.5% to 1.7%). In four areas (Firenze, the Netherlands, SEER and Connecticut) there were transient downward trends followed by increases back to pre-screening rates.
Conclusions: In areas with widespread sustained mammographic screening, trends in advanced breast cancer incidence do not support a substantial role for screening in the decrease in mortality.