R Maurício | PubMed Health

PubMed2006

Monitoring biofilm thickness using a non-destructive, on-line, electrical capacitance technique.

The present study was designed to evaluate indirect, non-invasive, on-line measurement of biofilm thickness using an electrical capacitance technique. Several assays were carried out and the results showed that, at a frequency of 1 kHz, electrical capacitance could be used to measure biofilm thickness indirectly (with a correlation coefficient of 0.9495). The reproducibility revealed by the assays was also highly satisfactory. However, in contrast to what was expected, there was an inverse relationship between electrical capacitance and biofilm thickness, i.e. electrical capacitance diminished with the increase in the biofilm thickness. The tests were also carried out at different frequencies (1 kHz, 10 kHz and 100 kHz).

Algorithms↗

PubMed2006

A characterization of selected endocrine disruptor compounds in a Portuguese wastewater treatment plant.

Anthropogenic compounds that are able to disrupt the endocrine system of wildlife species are a major cause for concern and have led to a demand for new screening methods. The identification and quantification of endocrine disruptor compounds at wastewater treatment plant is of major interest to assess the endocrine activity of wastewater treatment plant discharges into the environment. This study consists of a preliminary survey of concentrations of previously selected endocrine disruptor compounds, undertaken to establish environmental concentrations and to support a biological program assay exposing freshwater fish to them. Selected endocrine disrupting chemicals (APEs, bisphenol A and 17 beta-estradiol) were measured in samples from a wastewater treatment plant located in Lisbon (Portugal), using recent commercial enzyme-linked immunosorbent assay kits and also LC-MS/MS. The results show that the wastewater treatment plant treatment process is efficient on the removal of target endocrine disruptor compounds. However, environmentally significant concentrations are still present in the treated effluent. The results also show that enzyme-linked immunosorbent assay kit is suitable for routine analysis of the selected compounds. The results are also useful since the wastewater treatment plant is located in a Mediterranean region, which results in an effluent with its own characteristics.

Benzhydryl Compounds↗

PubMed2005

The content of the LRS chamber provides a new quality tool for the characterization of the donor platelet profile.

Cobe Trima version 4 is an apheresis system designed for the collection of combinations of Red Blood Cells (RBC), Platelets (PLT) and plasma components from a single donor. The validation of this apheresis system for PLT components in our institution evidenced the LRS efficacy, as leucoreduction was attained on a 100% basis. However, there were some unexpected occurrences regarding the PLT content. Certain donations showed large disagreements between programmed and obtained yields, not being found clear reasons for those outcomes. Furthermore, the mean platelet volume (MPV) was relatively low when compared with other platelets components produced by other methodologies. An investigation was initiated in order to know whether these shortcomings were donor or process/instrument related. A link was established between the raw material (donor), the process/instrument and the final product, and a new tool was introduced by the study of the LRS chamber. The LRS chamber content was assessed and the PLT cellular indices and PLT aggregation states compared with those obtained from the respective donor and the final product from the same origin. The storage stability of the final products was also analyzed based on these same tests to investigate if the initial low MPV had any deleterious effect during the shelf life of the components. Twenty five plateletpheresis donors, three of them new ones, were randomly selected for this study. For the first time, the content of the LRS chamber was used as a quality tool for identification of the cause of unexpected yields. Large aggregates remained in the LRS chamber in certain donors who were prone to undergo spontaneous aggregation, making the platelet yields low and platelet MPV very small. Based on repeated failures and on this new quality parameter showing LRS chamber abnormality, two donors were temporarily deferred from the panel. While it was not possible to identify the causes, it is appropriate to raise the question whether these profiles were Trima version 4 specific or not. Hence, further investigation is needed for a better clarification. In short, the simultaneous analysis of products and LRS content provided useful information not only for the characterization of donor-related phenomena but also helped in the identification of potential shortcomings in the machine performance allowing for remedial action to be taken on evidence based data.

Blood Donors↗