Impact of material emissions and sorption of volatile organic compounds on indoor air quality in a low energy building: Field measurements and modeling.

The assessment of VOC emission rates and sorption coefficients was performed for ten surfaces present within a classroom, using field and laboratory emission cells (FLEC) coupled to online and off-line VOC quantification techniques. A total of 21 identified VOCs were emitted by the different surfaces. VOC emission rates measured using PTR-ToF-MS were compared to gas chromatographic measurements. The results showed that the two methods are complementary to one another. Sorption parameters were also successfully measured for a mixture of 14 VOCs within a few hours (<17 hours per surface). A study of the spatial and temporal variability of the measured parameters was also carried out on the two surfaces that presented the most potential for interaction with VOCs, accounting for the largest surface areas within the room. The dataset of emission rates and sorption parameters was used in the INCA-Indoor model to predict indoor air concentrations of VOCs that are compared to experimental values measured in the room. Modeling results showed that sorption processes had a limited effect on indoor concentrations of VOCs for these field campaigns. Modeled daily profiles show good agreement with the experimental observations for VOCs such as toluene (indoor source) and xylenes (outdoor source) but underestimate concentrations of methanol (both indoor and outdoor sources).

Update on the clinical utility of an RNA interference-based treatment: focus on Patisiran.

RNA interference (RNAi) is a naturally existing endogenous mechanism for post-transcriptional gene regulation, nowadays commonly utilized for functional characterization of genes and development of potential treatment strategies for diseases. RNAi-based studies for therapy, after being examined for over a decade, are finally in the pipeline for developing a potential treatment for the mutated transthyretin (TTR) gene, which gives rise to a dysfunctional TTR protein. This dysfunctional protein causes TTR amyloidosis (ATTR), an inherited, progressively incapacitating, and often fatal genetic disorder. TTR is a protein produced in the liver, and functions as a carrier for retinol-binding protein and also thyroxine. This protein facilitates the transport of vitamin A around the human body. A mutation or misprint in the code of this protein results in an abnormal folding of the protein. Therefore, not only does the transportation of the vitamin A become disabled, but also there will be formation of clusters called amyloid deposits, which attack the heart and the nerves causing some patients to be unconditionally bound to bed. ATTR is a hereditary autosomal dominant disease with a 50% chance of inheritance by offspring, even with just one of the parents having a single defective allele of this gene. Alnylam Pharmaceuticals worked on the concept of RNAi therapy for years, which led to the introduction of lipid nanoparticles encircling small interfering RNAs. The drug showed extremely positive results since the first trial, and a great percentage of defective protein reduction. This drug was later named Patisiran.

Data on comparison between FLEC and CLIMPAQ methods used for fast sorption measurements of VOCs on building materials.

A test emission chamber called CLIMPAQ has been coupled to a chromatography analyzer GC to measure volatile organic compounds (VOC) concentration during a sorption experiments (Fast sorption measurements of VOCs on building materials: Part 2 - Comparison between FLEC and CLIMPAQ methods, (Rizk et al., In press) [1]). The equations used to calculate the mass transfer coefficient and the thickness of the boundary layer developed on the surface of a material are presented. In addition, the experimental profiles obtained using the CLIMPAQ chamber is also presented in the presence and the absence of a building material. Finally, the impact of chamber size on the obtained concentration profile using different chambers is shown using 3 types of chambers having different volumes, 1 m(3), 30 m(3) and a micro chamber of 40 mL.