16 Classical approaches require twin and family samples, the availability of which is limited by the substantial difficulties and high costs inherent in their recruitment.
As they discussed, some important limitations of their studies have to be noted: retrospective study, selection bias of samples, the availability of suitable tissue and absence of a set of nonmalignant control samples, all affected miRNA expression differences.
When designing PK PD studies in paediatrics certain factors need to be taken into account, e.g. the age range of the paediatric group, the therapeutic index, the possibility of collecting blood samples, the availability of validated PD endpoints for children and the availability of sensitive analytical methods.
The following criteria were used for our taxon sampling: the availability of cultures and ease of cultivation, the presence of a sizable research community, the history of research with this organism, the perceived potential for development of advanced molecular tools, and their key evolutionary positions in two major charophyte orders.
Methodological strengths of the present study include the large sample size, the availability of comparable survey instruments, the sampling strategies and methods of data collection, and also, the diverse nature of the various oral health-related behaviors.
This practice may be avoided because brain tissues contain much higher amount of these compounds than CSF samples, but it might be followed for CSF samples because the availability of CSF samples is usually very limited.
They found that kaolin (commercial sample) reduced the availability of two types of tannins and quinine (another plant secondary compound).
Strengths of this study include its large general population sample and the availability of data for village-level analysis.
A strength of this study was its community sample and the availability of several important health-related measures, including biological markers, for assessing the factors related to the long-term life dissatisfaction burden [ 55].
Nevertheless, the large and representative sample size, the availability of treatment outcomes, and the quality of laboratory data (all XDR TB defining drugs tested and drug susceptibility tests controlled for quality) strengthen the results of this study.
