CO2 dissolution and design aspects of a multiorifice oscillatory baffled column

Dissolution of CO2 in water was studied for a batch vertical multiorifice baffled column (MOBC) with varying orifice diameters (d0) of 6.4-30 mm and baffle open area (α) of 15-42%. Bubble size distributions (BSDs) and the overall volumetric CO2 mass transfer coefficient (KLa) were experimentally evaluated for very low superficial gas velocities, UG of 0.12-0.81 mm s-1, using 5% v/v CO2 in the inlet gas stream at a range of fluid oscillations (f = 0-10 Hz and x0 = 0-10 mm). Remarkably, baffles presenting large do = 30 mm and α = 36%, therefore in the range typically found for single-orifice oscillatory baffled columns, were outperformed with respect to BSD control and CO2 dissolution by the other baffle designs or the same aerated column operating without baffles or fluid oscillations. Flow visualization and bubble tracking experiments also presented in this study established that a small do of 10.5 mm combined with a small value of α = 15% generates sufficient, strong eddy mixing capable of generating and trapping an extremely large fraction of microbubbles in the MOBC. This resulted in increased interfacial area yielding KLa values up to 65 ± 12 h-1 in the range of the UG tested, representing up to 3-fold increase in the rate of CO2 dissolution when compared to the unbaffled, steady column. In addition, a modi fied oscillatory Reynolds number, Re′o and Strouhal number, St' were presented to assist on the design and scale-up of gas-liquid systems based on multiorifice oscillatory ba ffled columns. This work is relevant to gas-liquid or multiphase chemical and biological systems relying on efficient dissolution of gaseous compounds into a liquid medium.BBSRC -European Commissio

Anxiety and depression in patients with vocal fold nodules, edema and polyps

Purpose To compare the prevalence and severity of depression and anxiety among patients with vocal fold (VF) nodules, polyps and edema. At the same time the aim was to analyse association between severity of distress and the level of vocal handicap as well as to identify other factors related to severity of depression and anxiety in these patients. Methods To all participants were given five questionnaires: (1) questionnaire on socio-demographic and some other characteristics of patient; (2) Beck's Depression Inventory (BDI); (3) State-Trait Anxiety Inventory (STAI) 1 (State Anxiety); (4) STAI 2 (Trait Anxiety); and (5) Voice Handicap Index (VHI)-10. Results A total of 205 patients were included in this study. Mild-to-severe depression, according to BDI was present in 79 (38.6%) patients. Mild-to-severe state anxiety and trait anxiety were present in 199 (97.1%) and 200 (97.6%) patients, respectively. Only 10 patients had VHI-10 score lt = 11. Multivariate analyses showed that there were no significant differences in the level of depression and anxiety between patients with VF nodules, polyps and edema. The VHI-10 score was significantly higher in patients with VF edema in comparison with VF nodule patients (p = 0.001), as well as in comparison with VF polyp patients (p = 0.001). Conclusion The present study identified a high prevalence of psychological and vocal distress among patients with vocal disorders. Severity of depression and anxiety did not differ between patients with VF nodules, polyps and edema, and it was not related to the level of vocal handicap

Phytochemical and Botanical Therapies for Rosacea: A Systematic Review

Botanical and cosmeceutical therapies are commonly used to treat symptoms of rosacea such as facial erythema, papules/pustule counts, and telangiectasia. These products may contain plant extracts, phytochemicals, and herbal formulations. The objective of this study was to review clinical studies evaluating the use of botanical agents for the treatment of rosacea. MEDLINE and Embase databases were searched for clinical studies evaluating botanical therapies for rosacea. Major results were summarized, and study methodology was analyzed. Several botanical therapies may be promising for rosacea symptoms, but few studies are methodologically rigorous. Several plant extract and phytochemicals effectively improved facial erythema and papule/pustule counts caused by rosacea. Many studies are not methodologically rigorous. Further research is critical, as many botanicals have been evaluated in only one study. Botanical agents may reduce facial erythema and effectively improve papule/pustule counts associated with rosacea. Although promising, further research in the area is imperative