Biomedical subjects
T Gallagher
Publications and source records attributed to T Gallagher.
Evaluation of methods of computer estimation of interstitial and intracavitary dosimetry.
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Lighting a candle in the Romanian darkness.
Medical students in the Romanian city of Cluj came together to form 'Asklepyos', the Medical and Social Aid Organisation, in the aftermath of the 1989 revolt. Their initial concern with bringing comfort and material help to those most at risk as already depleted state agencies seized up, soon extended to championing the rights to orphans and handicapped people. Asklepyos won the respect and direct backing of western relief agencies because of its professionalism and idealism, attributes in short supply in a country profoundly damaged by the Ceausescu dictatorship. However, it has incurred the hostility of the state on account of its intention to encourage people to co-operate for social goals independent of compromised state agencies. In a society where self-organising associations have been hampered by personality disputes, ethnic suspicions, and past associations with communism, Asklepyos is recognised to be an exceptional initiative. If it founders, this may suggest that the chances of civil society being revitalised in Romania are currently bleak.
A multistate model for the fluorescence response of R-phycoerythrin.
Although strong fluorescence makes the R-phycoerythrin (R-PE) proteins increasingly useful in biological and clinical assays, they are subject to nonlinear effects including transitions to collective dark states and photodegradation, which complicate quantitative applications. We report measurements of R-PE fluorescence intensity as a function of incident power, duration of illumination and temperature. Emission intensity in the band at 570 nm is proportional to incident power for low power levels. At higher incident power, the emission at 570 nm is smaller than expected from a linear dependence on power. We propose that R-PE undergoes both reversible emission cessation on a millisecond time scale attributed to transitions to a collective dark state, and irreversible photodegradation on a time scale of minutes. Singlet oxygen scavengers such as dithiothreitol and n-propyl gallate have protective effects against the latter effect but not the former. Electrophoretic analysis of irradiated solutions of R-PE indicates that significant noncovalent aggregation is correlated with photodegradation. A multistate model based on fluorescence measurements and geometric analysis is proposed for the fluorophores in R-PE. The phycobilin fluorophores are partitioned into three groups: the phycourobilins (PUB) absorbing at 490 nm, one group of phycoerythobilins (PEB) absorbing at 530 nm (PEB-530) and another group of PEB absorbing at 560 nm (PEB-560). The two processes that result in the loss of fluorescence intensity are most likely associated with the PEB-560 group.
Patient dignity equals privacy.
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