Thrombotic thrombocytopenic purpura and hemolytic uremic syndrome (TTP/HUS). Description of a series of 35 patients

Subsequent to the implementation of a severity marker stamp in case notes, an audit was performed in 86 admissions with acute asthma to a specialist centre over a 12 month period. Compared to previous audit the documentation of severity markers was significantly better (PEFR: 52% vs 83% p = 0.001, Respiratory rate: 44% vs 81% p = 0.001, ABG: 72% vs 80% p = 0.04, air entry: 58% vs 86% p = 0.001, speech: 27% vs 86% p = 0.001, exhaustion: 4% vs 86% p = 0.001). In contrast to the previous audit where no patient received FiO2 > 0.35, 66% of the cases in the repeat audit received FiO2 0.60 (p = 0.001). The mean duration of admission was five days and showed highest partial correlation (r = 0.6) to the time in hours for the pulse to fall to 80/min. Multiple linear regression showed that this was the only variable best predicting the duration of admission (R2 = 0.3). Admission pulse rate (p = 0.04) and serum K+ (p = 0.04) best discriminated between patients admitted for over and under five days. Logistic regression identified only the admission pulse as significant in calculating the odds of the patient staying in the hospital for > 5 days.     

Multiple antibiotic resistance in Stenotrophomonas maltophilia

A cryptic multidrug resistance (MDR) system in Stenotrophomonas maltophilia, the expression of which is selectable by tetracycline, is described. Tetracycline resistance was the consequence of active efflux of the antibiotic, and it was associated with resistance to quinolones and chloramphenicol, but not to aminoglycosides or beta-lactam antibiotics. MDR is linked to the expression of an outer membrane protein (OMP54) both in a model system and in multidrug-resistant clinical isolates.     

Headache and decreased visual acuteness of sudden onset]

Lichen planus is a rare disorder in infants and children where it usually has the classical cutaneous pattern and only exceptionally involves the mucosa and skin appendages. A 9-year-old boy was referred to our department with a 4-month history of erythematous keratotic papules on the trunk and the upper and lower limbs. There were no signs of mucosal involvement. Subsequently white papules and striae, occasionally forming a lace like pattern, appeared on the penis and prepuce which quickly led to phimosis necessitating circumcision. Histologic examination of skin biopsy specimens and genital mucosa fragments confirmed the clinical diagnosis of lichen planus.     

Numerical study of the specimen size effect in the split Hopkinson pressure bar tests

A numerical and experimental assessment of the compression test in the split Hopkinson pressure bar (SHPB) has been made. The DYNA2D finite element code was employed in the numerical part. The aim of the work was to establish the influence of an important reduction in the specimen diameter on the results. To this end, several numerical experiments were carried out with different diameters. Experimental measurements using the SHPB technique were also performed. The material studied was the 7017 T73 aluminium alloy. In the simulations, stress histories were registered at different places in the incident and output bars, as well as in the test specimen. Numerical simulations show important three-dimensional effects in the SHPB, increasing for smaller diameters. Experiments show the same tendencies evinced by the numerical simulation. Care must be taken to minimize them to achieve the desirable uniaxial stress condition on the specimen.     

Effect of sulphate removal on the surface texture and acid-base properties of TiO2 (anatase)

Commercial anatase containing an appreciable amount of sulphur has been treated for sulphur removal by calcination at increasing temperatures or soaking with aqueous NaOH solutions. It has been found that both methods are active for sulphur removal, but the first one also leads to a sharp sintering of the titania particles. On the other hand, treatment with NaOH_aq leads to incorporation of sodium cations. Both treatments lead also to changes in surface acidity, as measured by Fourier transform infrared (FT-IR) monitoring of pyridine adsorption.     

Biofiltration of toluene in the absence and the presence of ethyl acetate under continuous and intermittent loading

BACKGROUND: Two peat biofilters were used for the removal of toluene from air for one year. One biofilter was fed with pure toluene and the other received 1:1 (by weight) ethyl acetate:toluene mixture. RESULTS: The biofilters were operated under continuous loading: the toluene inlet load (IL) at which 80% removal occurred was 116 g m^?3 h^?1 at 57 s gas residence time. Maximum elimination capacity of 360 g m^?3 h^?1 was obtained at an IL of 745 g m^?3 h^?1. The elimination of toluene was inhibited by the presence of ethyl acetate. Intermittent loading, with pollutants supplied for 16 h/day, 5 days/week, did not significantly affect the removal efficiency (RE). Biomass was fully activated in 2 h after night closures, but 6 h were required to recover RE after weekend closures. Live cell density remained relatively constant over the operational period, while the dead cell fraction increased. Finally, a 15 day starvation period was applied and operation then re‐started. Performance was restored with similar re‐acclimatization period to that after weekend closures, and a reduction in dead cell fraction was observed. CONCLUSION: This study demonstrates the capacity of the system to handle intermittent loading conditions that are common in industrial practices, including long‐term starvation. Copyright © 2008 Society of Chemical Industry     

Entanglement network and relaxation temperature dependence of single‐site catalyzed ethylene/1‐hexene copolymers

In this work, we investigate the linear viscoelastic response of high molecular weight ethylene/1‐hexene copolymers, characterized by a narrow molecular weight distribution and comonomer content in the range from 0 to 10 mol %. A variation in the entanglement plateau modulus has been found in agreement with the recently developed packing length model. The packing model applied to viscoelastic data suggests decreased values of the characteristic ratio, accordingly with recent computer simulation results. The flow activation energy increases as the side chain content increases. This feature is thought to be related to the mobility of the molecules. The presence of side branches due to the comonomer hinders the mobility of the molecules, and increases the thermal barrier for the segmental motion. Then in the comonomer content range studied, the increase of the flow activation energy goes parallel with a decrease in the characteristic ratio. This result suggests that more parameters than only the stiffness of the chain modulate the thermal dependence of viscoelastic properties. A more refined study is necessary combining experiments with computer simulations in order to elucidate these aspects. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Tracking human faecal contamination in tropical reservoirs in Puerto Rico

Using a combination of chemical and microbiological (culture-dependent and -independent) approaches, sources of human faecal contamination were identified in two water reservoirs in Puerto Rico – Guajataca and La Plata. Fluorescence from optical brighteners (OB) – commonly found in laundry detergents – was used as an indicator of contamination from septic systems and other household discharges. Traditional indicators of faecal contamination (e.g. Escherichia coli; faecal enterococci) were enumerated, and human faecal contamination was confirmed through detection of Bifidobacterium adolescentis utilizing polymerase chain reaction (PCR)-based analyses. For Guajataca Reservoir, four of 19 sampling sites (21%) were positive for the presence of B. adolescentis under baseflow conditions. The OB fluorescence data suggested that the most likely source for three of these sites was residential, whereas the source of contamination at the remaining site, although of human origin, was probably non-residential. B. adolescentis was present in 83% (19 of 23) of the sampling sites in La Plata. The La Plata sources were more difficult to identify because samples were taken under stormflow conditions, although the presence of OB fluorescence suggested a residential origin in a number of instances. OB fluorescence and traditional bacterial indicators of faecal contamination produced a number of false positive and negative findings for both reservoirs, pointing to the importance of understanding the limitations of these tools for tropical freshwater systems. The results of this study should be useful in developing a weight-of-evidence approach for the identification of potential sources and extent of human faecal contamination in similar tropical reservoirs, a necessary step in the development of management plans to reduce or eliminate these sources.