The first one is based on topological characteristics, for example by counting number of neighbors using the same channel [37].
This approach is more robust than an approach adjusting only for patient's baseline characteristics, for example, by propensity score methods.
Other authors have tried to define a useful threshold based on distribution characteristics, for example by using the mean plus one s.d. in the general population (Holzner et al, 2003).
Although the work by Shepard and others 1 had a limited sample size and statistical power, it is likely that the intervention and control groups differed beyond these six characteristics (for example, by the number of providers and the demographic and epidemiological characteristics of the catchment population among others) and hence not "perfectly matched".
These characteristics are prized, for example, by makers of cell phones and computers.
Furthermore, attempts to relate treatment efficacy to molecular or cellular characteristics of tumours, for example, by systems biology approach, will be rather difficult when data are categorised.
Further, the dose of drug may be better adjusted based on patient characteristics; for example, a dose defined by the weight of the patient rather than a predefined dose (that is, 2 to 3 g).
Although antimicrobial drug resistant T. vaginalis clearly exists, not all treatment failures are solely attributable to parasite genetic characteristics; for example, many isolates received by the susceptibility testing service at CDC do not display resistance in vitro.
These techniques are based either on the physical properties of the cells (for example, cell density by ficoll centrifugation or cell size by filtration) or on their immunological characteristics (for example, cell surface antigens of DTCs/CTCs by immunoenrichment or markers of hematopoietic cells by immunodepletion).
However, the measured PET signal comprises non-specific uptake (dependent on the tissue blood volume fraction, as well as other tissue characteristics, for example, size of endothelial fenestrae by which the antibody passes through the capillary wall) and potentially target antigen-mediated specific uptake.
This means that a characteristic blue light emitted, for example, by an excited helium atom as it changes from a higher to a lower internal energy state would no longer appear blue when one looks at this light coming from helium atoms that move very rapidly away from the Earth with, say, a galaxy.
