[Characterization of a Portuguese population with systemic lupus erytematosus]. / Caracterização de uma população Portuguesa de doentes com lupus eritematoso sistémico.

UNLABELLED: To characterize systemic lupus erythematosus (SLE) in Portuguese patients and to identify differences in diseases expression related to sex and ethnicity. PATIENTS AND METHODS: Retrospective cohort analysis of patients with SLE followed at five Rheumatology Departments between 1976 and 2006. Demographic data, diseases manifestations, medications used, co morbidity and damage scores were recorded. RESULTS: Five hundred forty four patients were studied, 93% female, 89% Caucasians, with an average age at disease diagnosis of 35 years. The most frequent clinical features were musculoskeletal (91%), cutaneous and mucous membrane (90%) and the hematological involvement (58%). Renal diseases and serositis occurred more often in males while myositis was more common in black patients. Immunological features included the presence of anti-nuclear antibodies in 99% of the patients, anti-DNA (76%) anti-SSA (33%), anti-SSB (20%), anti-RNP (26%), anti-Sm (22%), anticardiolipine (31%) and lupus anticoagulant (21%). Anti-SSA, anti-RNP, and anti-Sm antibodies were significantly more prevalent among black patients. The presence and severity of damage measured by SLICC/ACR was similar between sexes and ethnicities. In multivariate analyses diseases duration and the presence of hypertension showed a positive association, while educational and antimalarials were negatively associated with the presence of damage. CONCLUSION: In this cohort of Portuguese patients SLE present clinical features similar to those observed in other predominantly Caucasian populations, albeit a higher prevalence of anti-RNP and anti-Sm antibodies was observed. Some particular features were associated with male sex and African ethnicity. Some socio-demographic and clinical variables were associated with damage accrual.

Applying fine bubble aeration to small aeration tanks.

Because the aeration system in an activated sludge plant typically represents a large part of the total energy requirements, designers and operators need accurate oxygen transfer information to make the aeration system as energy efficient as possible. This paper presents clean water tests performed at 38 wastewater treatment plants. The Specific Aeration Efficiency results (SAE, kgO2/kWh) are reported for: (1) large open channels (volume higher than 1000 m3), (2) small open channels, (3) total floor coverage cylindrical tanks, and (4) cylindrical tanks with a grid arrangement. Some practical guidelines can be drawn, some of them being: (1) high SAE can be achieved at small aeration tanks (< 1000 m3), applying cylindrical tanks with a total floor coverage arrangement of diffusers, volumetric blowers, and moderate air flow rates per diffuser area; (2) the high investment cost of this configuration can be justified with respect to a grid layout characterized by spiral liquid circulation which affects the oxygen transfer; (3) small open channels can meet sufficient SAE values but fail to meet in this range of tank volumes those of total floor coverage cylindrical tanks.

Transfer number in fine bubble diffused aeration systems.

On the basis of full-scale data from 58 clean water tests performed in 26 activated sludge tanks equipped with fine bubble diffusers and of a theoretical approach, it can be stated that fine bubble aeration systems with total floor coverage arrangement provide higher kLa values and the lowest spiral liquid circulation. An efficiency criterion for oxygen transfer (NT) was defined on the basis of the dimensional analysis. The transfer number NT allows us to take account of the impact of vertical liquid circulation movements on oxygen transfer. The values of NT calculated from the results of full scale nonsteady-state clean water tests vary from 5.3 x 10(-5) to 9.1 x 10(-5) and are directly dependent upon the arrangement of air diffusers. It has been shown that the highest transfer numbers corresponded to the total floor coverage arrangement and the average calculated NT values is 7.7 x 10(-5), independently of the diffuser density and of the gas velocity, over the ranges studied. The lowest transfer numbers are obtained when the diffusers are located in separate grids, and the transfer number is reduced with increasing air flow rate.