11 research outputs found
Smart Tungsten-based Alloys for a First Wall of DEMO
During an accident with loss-of-coolant and air ingress in DEMO, the temperature of tungsten first wall cladding may exceed 1000 °C and remain for months leading to tungsten oxidation. The radioactive tungsten oxide can be mobilized to the environment at rates of 10–150 kg per hour. Smart tungsten-based alloys are under development to address this issue. Alloys are aimed to function as pure tungsten during regular plasma operation of DEMO. During an accident, alloying elements will create a protective layer, suppressing release of W oxide. Bulk smart alloys were developed by using mechanical alloying and field-assisted sintering technology. The mechanical alloying process was optimized leading to an increased powder production by at least 40 %. Smart alloys and tungsten were tested under a variety of DEMO-relevant plasma conditions. Both materials demonstrated similar sputtering resistance to deuterium plasma. Under accident conditions, alloys feature a 40-fold reduction of W release compared to that of pure tungsten.</p
Apoptosis resistance in pigmented villonodular synovitis
Objective: Pigmented villonodular synovitis
(PVNS) is a proliferative lesion originating from
synovial tissue with a locally aggressive behaviour. We
analysed the pathogenetic role of apoptosis resistance for
sustained cell proliferation in PVNS. Methods: The
expression of bcl-2, p53 and Ki-67 was examined in 80
cases of PVNS using immunohistochemistry. In 43 of
these cases, DNA content and distribution of cell-cycle
phases were investigated by flow cytometry.
Additionally, 10 cases of PVNS were analysed by multiparametric
flow cytometry for expression of p53,
caspase3, and bcl-2 and by TUNEL to detect DNA
fragmentation. Results: No apoptotic cell fractions were
detected in any investigated cases. Expression of bcl-2
was found in 84% of cases (up to 6.5% of cells) and was
significantly associated with DNA-fragmentation
observed by TUNEL (p=0.037). Orthologous p53
expression was observed in 37% of cases. The level of
p53 expression correlated with the proliferative activity
and the expression of both caspase3 (p=0.017) and bcl-2
(p=0.0013). (No statistically significant correlations
between expression of bcl-2, p53, caspase3, DNA
fragmentation or proliferative index and age, sex of
patients, disease recurrence, growth pattern or size of
lesion were found). Conclusion: Apoptosis resistance is
a critical event in the progression of PVNS and may
contribute to the survival of the proliferating synovial
cells in PVNS and to the permanent slow progression of
these lesions
Smart Tungsten-based Alloys for a First Wall of DEMO
During an accident with loss-of-coolant and air ingress in DEMO, the temperature of tungsten first wall cladding may exceed 1000 °C and remain for months leading to tungsten oxidation. The radioactive tungsten oxide can be mobilized to the environment at rates of 10–150 kg per hour. Smart tungsten-based alloys are under development to address this issue. Alloys are aimed to function as pure tungsten during regular plasma operation of DEMO. During an accident, alloying elements will create a protective layer, suppressing release of W oxide.Bulk smart alloys were developed by using mechanical alloying and field-assisted sintering technology. The mechanical alloying process was optimized leading to an increased powder production by at least 40 %. Smart alloys and tungsten were tested under a variety of DEMO-relevant plasma conditions. Both materials demonstrated similar sputtering resistance to deuterium plasma. Under accident conditions, alloys feature a 40-fold reduction of W release compared to that of pure tungsten