Laser reflectance measurement for the online monitoring of Chlorella sorokiniana biomass concentration.

Fast and reliable methods to determine biomass concentration are necessary to facilitate the large scale production of microalgae. A method for the rapid estimation of Chlorella sorokiniana biomass concentration was developed. The method translates the suspension particle size spectrum gathered though laser reflectance into biomass concentration by means of two machine learning modelling techniques. In each case, the model hyper-parameters were selected applying a simulated annealing algorithm. The results show that dry biomass concentration can be estimated with a very good accuracy (R2=0.87). The presented method seems to be suited to perform fast estimations of biomass concentration in suspensions of microalgae cultivated in moderately turbid media with tendency to aggregate.

Estimation of Chlamydomonas reinhardtii biomass concentration from chord length distribution data.

A novel method to estimate the concentration of Chlamydomonas reinhardtii biomass was developed. The method employs the chord length distribution information gathered by means of a focused beam reflectance probe immersed in the culture sample and processes the data through a feedforward multilayer perceptron. The multilayer perceptron architecture was systematically optimised through the application of a simulated annealing algorithm. The method developed can predict the concentration of microalgae with acceptable accuracy and, with further development, it could be implemented online to monitor the aggregation status and biomass concentration of microalgal cultures.

Do serum C-reactive protein and interleukin-6 predict kidney scarring after urinary tract infection?

OBJECTIVE: To investigate if serum C-reactive protein (s-CRP) and interleukin 6 (s-IL6) provide information for predicting renal damage and for DMSA patient selection in children with urinary tract infection (UTI). METHODS: This observational study was carried out in children with UTI. s-CRP and s-IL6 were measured at UTI diagnosis. Patients forming renal scarring were identified by DMSA scans. The usefulness of s-CRP and s-IL6 measurements for nephropathy scarring diagnosis was evaluated using diagnostic quality and efficiency indexes. RESULTS: Thirty-two children were included in the study. Eight showed renal scarring after the follow-up. The s-CRP was 110.23 ± 59.69 mg/L and 52.46 ± 63.13 mg/L for patients with and without renal scarring. The s-IL6 concentration was 18.34 ± 11.80 pg/mL and 8.07 ± 9.51 pg/mL respectively. The cut-off points for optimum nephropathy scarring diagnosis were 115 mg/L for s-CRP and 20 pg/mL for s-IL6. The value of highest sensitivity for s-CRP was >5 mg/L (S:100 %) and greatest specificity was >150 mg/L (Sp:95.83). The highest sensitivity for s-IL6 was >4 pg/mL (S:100 %) and the maximum specificity was >40 pg/mL (Sp:100 %). CONCLUSIONS: Results confirm that children who will develop renal scarring show higher levels of s-IL6 and s-CRP at UTI diagnosis. However, none of the techniques provide sufficient information for predicting renal damage in all patients and for DMSA patient selection.

Urinary interleukin-6 is useful in distinguishing between upper and lower urinary tract infections.

This study was designed to determine whether the measurement of interleukin (IL)-6 in urine is useful for distinguishing between acute pyelonephritis and lower urinary tract infection. This observational study was carried out at León Hospital (Spain) on 35 patients (ten boys) aged between 0 and 14 years with urinary tract infection. Urinary levels of IL-6 were determined with enzyme-linked immunosorbent assay (ELISA) at diagnosis and after recovery. Renal dimercaptosuccinate acid (DMSA) scan was performed on all patients to discard or confirm acute pyelonephritis. The mean urinary concentration [x +/- standard deviation (SD)] of IL-6 at diagnosis was 20.3 +/- 23.3 and 5.3 +/- 9.7 pg/ml in patients with acute pyelonephritis and lower urinary infection, respectively [95% confidence interval (CI): 2.6-27.4; p < 0.01]. Specificity for a value of IL-6 >15 pg/ml, was 94.1% (95% CI: 91.1-97.1). Positive predictive value for IL-6 >15 pg/ml was 87.5% (95% CI: 81.1-93.8). IL-6 was undetectable in the urine of both groups of patients at the time of recovery. Urinary levels of IL-6 are useful in differentiating between upper and lower urinary tract infection in children. In this clinical setting, a value >15 pg/ml is a strong indicator of acute pyelonephritis.