Results of these studies have in general been contradictory to some extent, because of small sample sizes, absence of a non-pregnant control group or use of analytical methodologies of varying sensitivities.
Although similar to animals described in previous reports (7, 9 ), none of the sampled animals showed evidence of disease at the time of sampling; however, absence of clinical disease does not exclude the possibility of subclinical or past infections.
Alternatively, this difference might be an artifact of restricted sampling because of the absence of out-of-basin sampling.
For the different samples soaked in the same solution for a given duration, the strength of samples containing fly ash is larger than that of samples in absence of fly ash, and the strength of sample containing quartz sand is larger than that of samples in absence of quartz sand.
The inhibition rate was calculated using the following formula: where Δ Asample, Δ Acontrol and Δ Ablank denote changes in absorbance at 340 nm in the presence of sample, in the absence of sample, and in the absence of enzyme, respectively.
Of course our pilot study has the limitations of a small sample size, absence of a control group, and non-random assignment to group or individual use of the 'Taking Control' booklet.
A single spot urine sample and absence of quantification of albuminuria was also a limitation.
21 In this clinical study, the criteria for inclusion of "normal" older sample were: absence of central nervous system pathological conditions and other health problems related to cognitive impairment (alcoholism, drug addiction, or systemic diseases, etc).
Limitations of the study also include a small sample size, absence of a control group and short-term follow-up.
Previous studies had limitations such as small sample sizes, absence of follow up data and lack of a dimensional approach.
