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AbstractThis work was conducted at the largest petrochemical membrane bioreactor (MBR) plant in the world. The effectiveness of MBR technology to treat petrochemical effluents was studied. The treated effluent is discharged in a very sensitive water body and needs to satisfy strict limits. To optimize MBR operation a pilot-scale MBR was set-up that received the same petrochemical effluents as the full scale. In the pre-denitrification configurations, ammonification was not effective. Variable removal of heavy metals/metalloids was obtained by the MBR with As, B, Ba, Mo, Al, Ni, Se, Sb, V and Zn removal being less than 40%, Pb, Hg, Cu, Ag, Cr, Mn and Co removal of 40–70% and only Fe removal being higher than 70%. Sludge clogging was observed in the membrane module; the accumulation of COD, N, P, As, Zn, Mo, Ni, Cd, Sb, Fe, Se and Co in the clogged sludge was higher than that in the activated sludge. The adoption of MBR coupled with suitable physicochemical pre-treatment was able to safeguard the treated effluent quality.

This work was conducted at the largest petrochemical membrane bioreactor (MBR) plant in the world. The effectiveness of MBR technology to treat petrochemical effluents was studied. The treated effluent is discharged in a very sensitive water body and needs to satisfy strict limits. To optimize MBR operation a pilot-scale MBR was set-up that received the same petrochemical effluents as the full scale. In the pre-denitrification configurations, ammonification was not effective. Variable removal of heavy metals/metalloids was obtained by the MBR with As, B, Ba, Mo, Al, Ni, Se, Sb, V and Zn removal being less than 40%, Pb, Hg, Cu, Ag, Cr, Mn and Co removal of 40–70% and only Fe removal being higher than 70%. Sludge clogging was observed in the membrane module; the accumulation of COD, N, P, As, Zn, Mo, Ni, Cd, Sb, Fe, Se and Co in the clogged sludge was higher than that in the activated sludge. The adoption of MBR coupled with suitable physicochemical pre-treatment was able to safeguard the treated effluent quality.

Abstract Polyethylene (PE) wear is a focal issue in joint replacement, so it is essential to understand how it takes place in vivo. PE wear is a multifactorial process with a complex interaction of variables related to the materials used, the mechanical conditions, operative procedures for implantation, activity of the patient and use of prosthesis. We retrieved 65 PE inserts with the respective femoral and tibial components (50 inserts of total knee prostheses and 15 monocompartmental prostheses) from first revision surgeries. The average age of the patients was 68.3 years; the average time to revision was 41.5 months. Macroscopic observation considered the grade, topography and type of wear. Degradation was also studied with scanning electron microscopy. No direct relationship was found between the level of wear and the survival of total or monocompartmental knee prostheses. The duration of 11 (22%) total prosthetic inserts with grade 2 wear was 42.6 months vs. 51.5 months of 17 (34%) total inserts with grade 1 wear. However, study of the relationship between wear grade and wear topography in total inserts suggested that there was a significant connection. In fact, the 22 (44%) prostheses with central and symmetrical wear never showed wear greater than grade 1. Instead, of the remaining 28 prostheses (56%) without central and symmetric wear, only 3 had grade 0 wear. Finally, considering the relationship between wear grade and type of wear, all 18 inserts (27.7%) with grade 2 or 3 wear had 100% delamination. In conclusion, this study suggests that the correct positioning of the prosthetic components, besides its quality, is an important cause of polyethylene wear.

Apnea is one of the most common neonatal respiratory disorders and consist in pauses in respiratory movements lasting more than 20 seconds. The objective of this study was to determine the characteristics of skin blood flow microcirculation in preterm newborn with frequent apneic events with Laser-Doppler-Flowmetry. We have studied 20 preterm newborns with a mean weight of 1560 g (range 1140 – 2150) and a mean post-conceptional age of 31,2 weeks (range 28 – 33). The laser Doppler skin blood flow was measured during 88 apneic events. The newborns were divided into two different groups: GROUP 1 concerning apneic spells in the first 5 days of life; GROUP 2 concerning apneic events in the same newborns from 6 to 10 days of life. We included in our study only 13 of 20 newborns, in which there were apneic events during both periods. A statistically significant difference (p<0.01) was found considering the percentage reduction of skin blood flow perfusion (SBFP). A remarkable increase of mean SBFP reduction was noted in every newborn older than five days. LDF can assume an important role during apneic events suggesting that the newborn is more capable of contrasting the negative effects of apneic spells, centralizing the circle in favour of vital organs.

Summary A time-dependent degree of immunosuppression or immunostimulation which may be correlated to pharmacokinetic variables was obtained by administering a single dose of ofloxacin, norfloxacin, pipemidic and piromidic acid to healthy volunteers. The plasma samples collected before drug administration and then at various time intervals were tested for their immunomodifying activity by employing a modified 2-way mixed lymphocyte reaction and a PMN chemotactic assay. Our results show that some of the quinolones tested — norfloxacin, pipemidic acid, piromidic acid — have an immunosuppressive activity.