EphrinB3 blocks EphB3 dependence receptor functions to prevent cell death following traumatic brain injury.

Eph receptor tyrosine kinases and their membrane-bound ligands, ephrins, have a variety of roles in the developing and adult central nervous system that require direct cell-cell interactions; including regulating axon path finding, cell proliferation, migration and synaptic plasticity. Recently, we identified a novel pro-survival role for ephrins in the adult subventricular zone, where ephrinB3 blocks Eph-mediated cell death during adult neurogenesis. Here, we examined whether EphB3 mediates cell death in the adult forebrain following traumatic brain injury and whether ephrinB3 infusion could limit this effect. We show that EphB3 co-labels with microtubule-associated protein 2-positive neurons in the adult cortex and is closely associated with ephrinB3 ligand, which is reduced following controlled cortical impact (CCI) injury. In the complete absence of EphB3 (EphB3(-/-)), we observed reduced terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL), and functional improvements in motor deficits after CCI injury as compared with wild-type and ephrinB3(-/-) mice. We also demonstrated that EphB3 exhibits dependence receptor characteristics as it is cleaved by caspases and induces cell death, which is not observed in the presence of ephrinB3. Following trauma, infusion of pre-clustered ephrinB3-Fc molecules (eB3-Fc) into the contralateral ventricle reduced cortical infarct volume and TUNEL staining in the cortex, dentate gyrus and CA3 hippocampus of wild-type and ephrinB3(-/-) mice, but not EphB3(-/-) mice. Similarly, application of eB3-Fc improved motor functions after CCI injury. We conclude that EphB3 mediates cell death in the adult cortex through a novel dependence receptor-mediated cell death mechanism in the injured adult cortex and is attenuated following ephrinB3 stimulation.

Assessment of a microalgae pond for post-treatment of the effluent from an anaerobic fixed bed reactor treating distillery wastewater.

An evaluation of the performance of a laboratory-scale microalgae pond treating effluent from an anaerobic fixed bed reactor digesting distillery wastewater was carried out. The microalgae pond operated with an effluent recycling (R) of 10:1 with respect to the influent and at surface organic loading rates of 418 kg COD ha(-1) day(-1) and 92 kg BOD5 ha(-1) day(-1). During the experiment total chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total solids (TS), total suspended solids (TSS), volatile suspended solids (VSS), total nitrogen, ammonia, total phosphorus, orthophosphate, total chlorophyll (CT) and chlorophyll a (Ca) concentrations were monitored. Overall COD and BOD5 removal efficiencies of 98.2% and 98.8% were obtained. The global solids removal efficiencies were of 93.2%, 92.6% and 97.6% for TS, TSS and VSS, respectively. The removal efficiencies obtained for organic nitrogen and ammonia were 90.2% and 84.1%, respectively. Finally, the removals for total phosphorus and orthophosphate were 85.5% and 87.3%, respectively. It was demonstrated that microalgae grew in this waste by determination of the total chlorophyll and chlorophyll a in the effluent.

Effect of the organic loading rate on the performance of anaerobic acidogenic fermentation of two-phase olive mill solid residue.

A study of the effect of the organic loading rate (OLR) on the anaerobic acidogenic fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the acidogenic fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).

Anaerobic fluidized bed reactor application to tropical fruit wine effluent.

The influence of the organic loading rate (OLR), the fluidization level (FL) and the particle diameter of natural zeolite used as support (D(p)), was evaluated at a laboratory scale anaerobic fluidized bed reactor (AFBR), treating tropical fruit wine effluent (vinasse). The experiment was carried out at an OLR from 2-5 kg COD/m3 d, FL of 20 and 40% and D(p) from 0.25 to 0.80 mm. It was demonstrated that OLR and FL had a slight influence on chemical oxygen demand removal and strong influence on the methane production rate. The COD removal was slightly higher for the higher particle diameter used. Additionally using the scanning electron microscope (SEM), it was observed that natural zeolites have excellent physical characteristics as a support medium in AFBR.

Piggery waste treatment by using down-flow anaerobic fixed bed reactors.

A study of the role of the depth in the performance of laboratory-scale down-flow anaerobic fixed-bed reactors (DFAFBR) was carried out at different nominal hydraulic retention times (HRT(N)) using piggery waste as substrate at different influent concentrations (2, 4, 6 and 8 g COD/L). The profiles of soluble chemical oxygen demand (COD) (SCOD), organic nitrogen (O.N.), ammonia nitrogen (A.N.), pH and electrical conductivity (E.C.) through the reactor depths showed an initial highly active zone, which was located around the first half of the reactor depth, and a second zone with a lower biological activity. It was found that the depth of the active zone decreased as the HRT(N) increased and that the slopes of the profiles obtained increased with the rise in the influent concentration. A hydraulic test showed an increase in the dispersion number when the HRT(N) increased. The reactors showed a hydraulic pattern between plug-flow and back-mix. The real values of HRT (Theta) also defined as real contact times were determined to be 0.7, 2.1, 3.4, 4.7, 6.4 and 8 days for values of HRT(N) of 1, 2, 3, 4, 5 and 6 days, respectively. It was found that the concentration of SCOD within the reactor decreased exponentially with the increase in the value of theta. Additionally, the influent concentration had a strong influence on the SCOD variation concentration, mainly at values of theta under 1.5 days, which corresponded to the first part of the reactors.

Evaluation of the quality of the water in El Hondo natural park located in the east of Spain.

The purpose of the present work was to evaluate the quality of the water in El Hondo Park, an important wetland located in the east of Spain (province of Alicante) and included on the Ramsar List. The influence of the input of pollutants was assessed over a 14-month period in order to propose remedial action. Three different sources of waters were studied: irrigation water, brackish water and reservoir water. The irrigation water was found to have a high value of conductivity with high concentrations of Cl-, SO(4)2-, Na+ and K+ due to the influence of the brackish water. The concentration of organic matter given as CODT (total chemical oxygen demand) was found to be in the range of 70-600 mg/L of CODT, which was comparable to low-middle strength wastewater. A high concentration of Chlorophyll (a) was found in samples of reservoir water and the eutrophication of this water was thus observed. A high linear relationship was found among CODT, CODF (filtered COD) and BOD5; among electrical conductivity (E.C.), Cl-, SO4(-2), Na+, K+, Ca2+ and Mg2+ and among pH, CO3H- and CO(3)2- in all the samples evaluated. Taking this fact into consideration, a simplified water quality index (WQI) was calculated. Using this parameter, the quality of the water from different sources and its variation during the period evaluated was determined to be at a maximum during the months of December to February, which coincided with the period of high precipitations and low temperature. The highest values of this parameter were found in the samples corresponding to the reservoir water while the lowest values were found in the samples of the brackish water. By determination of the WQI, the influence of the brackish water on the quality of water for irrigation and reservoir waters was confirmed.

Production of biomass (algae-bacteria) by using a mixture of settled swine and sewage as substrate.

This paper presents the use of a mixture of settled swine and sewage as substrate for biomass production, mainly constituted by microalgae Chlorella vulgaris and aerobic bacteria, growing outdoor at different dilution rates in a continuous mode. The experiments were carried out in 16-litre volume laboratory ponds operating at hydraulic retention times (HRT) in a range of 4-14 days equivalent to dilution rates (D) in a range of 0.250-0.071 d(-1). Total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), total biochemical oxygen demand (TBOD(5)), total suspended solids (TSS), volatile suspended solids (VSS), total Chlorophyll (S C), total Kjeldahl nitrogen (TKN), ammonia nitrogen, total phosphorous, orthophosphate and pH were monitored. An empirical relationship between the dilution rate (D) and the removal efficiencies of TCOD, SCOD, TBOD(5), TKN and total phosphorous was found. The occurrence of an inhibition process for TCOD, TBOD(5), TKN and total phosphorous removals was observed. The Andrews kinetic model was successfully applied to these experimental data, while the Monod model was more suitable for studying the variation of the SCOD removal rate with the effluent SCOD concentration. The maximum microalgal biomass productivity was found to be in the range of 93-98 mg VSS(A)/L d (37.2-39.2 g/m(2)d) at dilution rates in the range of 0.167-0.250 d(-1), where VSS(A) is the concentration of microalgae expressed in VSS. In the case of the bacteria, the productivity increased linearly with the dilution rate being maximum at a D value of 0.25 d(-1). It was concluded that the mixture of pre-treated swine and sewage used as substrate, contributed to the obtention of a high biomass (microalgae-bacteria) production, providing a simple technology feasible to be applied in developing countries.

An evaluation of variables affecting the stability and performance of down-flow anaerobic fixed bed reactors treating piggery wastewater.

The influence of the most important variables on the stability and performance of down-flow anaerobic fixed bed reactors treating piggery wastewater after primary sedimentation was evaluated at HRT in the range of 1-6 d and influent substrate concentration in the range of 2 to 12 g TCOD l(-1). The effect of HRT was more pronounced compared to that of influent strength. An increase in the HRT increased the process stability and process performance at different influent strengths. TCOD, SCOD, BOD5 TSS, organic nitrogen (N) and Orthophosphate (P) removals increased with the HRT, independently of the initial substrate concentration (S0). The increase in S0 brought about an increase in the attached biomass concentration (X) at the end of the experiment. Two empirical models based on the individual effect of HRT, X and S0 were evaluated and found to be adequate to describe the influence of these variables on the process performance. The first model took all the above-mentioned variables into consideration while the second model was simplified and based on the use of HRT as the only independent variable. The results obtained by using both models were found to be similar. This demonstrated that independently of the characteristics of the operation, the behaviour and performance of the reactors were comparable. The methane yield coefficient was found to be 0.3371 methane g(-1) TCOD removed.

Effect of organic loading rate on the stability, operational parameters and performance of a secondary upflow anaerobic sludge bed reactor treating piggery waste.

A study of anaerobic digestion of piggery wastewater was carried out in a laboratory-scale sludge bed reactor as a secondary treatment. The effect of organic volumetric loading rates (BV) in the range of 1.0-8.1 g TCOD/ld on the process performance was evaluated. The best results were obtained at BV equal to or lower than 4 g TCOD/ld. At higher BV values, the removal efficiency of the process decreased suddenly. A linear relationship was found between the effluent SCOD and the TVFA/alkalinity ratio (P). A relationship was found among the different operational variables (BV , removal efficiency, effluent soluble COD, soluble COD removal rate (R), retention factor (phi), specific microbial growth rate (mu), methane production rate per volume of reactor and per volume of waste treated--QM and qM, respectively) and the corresponding regression equations were obtained. An increase of BV determined a decrease of removal efficiency, phi and qM and an increase of effluent soluble COD, mu, R and QM. The value of the maximum specific microbial growth rate (muM) determined through the equation that correlated BV and mu was found to be 0.19 d(-1). This value was of the same magnitude as those reported in other works of anaerobic digestion of piggery waste.

Evaluation of a laboratory and full-scale microalgae pond for tertiary treatment of piggery wastes.

Piggery wastes tertiary treatment in laboratory and full-scale microalgal ponds was evaluated. COD, BOD, inorganic nitrogen and orthophosphate removals of up to 57%, 69%, 79% and 74%, respectively, were obtained. The effect of the hydraulic retention time (HRT) on removal efficiencies followed an exponential relationship. COD, BOD and orthophosphate removal rate decreased with increased effluent concentration while the inorganic nitrogen removal rate increased with an increasing effluent substrate concentration at inorganic nitrogen concentration values lower than 0.07 g l(-1). Values of maximum substrate removal rate, half rate constant, cell yield coefficient, endogenous constant and maximum specific growth rate were 7.1 +/- 0.5 d(-1), 0.21 +/- 0.02 g l(-1), 0.26 +/- 0.01 g VSS g(-1) COD, 0.012 +/- 0.001 d(-1)and 1.9 +/- 0.9 d(-1), respectively. At full-scale, effluent COD, BOD, MPN, inorganic nitrogen and orthophosphate decreased while pH and Chlorophyll a increased with the operation time. It was found that the use of the final effluent as drinking water did not affect pigs growth.

Population dynamic of algae and bacteria in an oxidation channel.

A study on algae and bacteria population changes, as a function of time, was carried out in a pilot scale oxidation channel bioreactor using a carrousel system. Total Coliforms, Pseudomonas aeruginosa, and Streptococcus faecalis, the most common bacteria found in sewage, Scenedesmus obliquus and Chlorella vulgaris were the microalgae considered in this work. Physicochemical parameters such as COD, BOD, Chlorophyll a, nitrogen, and phosphorous compounds were studied and determined during the experiments. It was demonstrated that the level of wastewater contamination could be predicted based on the bacterial and algae composition. The relationships between the algae and bacteria population, and the variation of these microorganism populations as a measurement of the level of purification were established. The oxidation channel was able to remove a considerable amount of organic matter and pathogenic microorganisms in a relatively short time. The nitrification process could not be measured. The increase in the relative concentration of microalgae contributed toward improving the global efficiency of the system as well as reducing the pathogenic bacteria population.

Growth of Phormidium sp. in aerobic secondary piggery waste-water.

The potential of a cyanobacterium Phormidium sp., for the tertiary treatment of piggery waste-water chemical oxygen demand > or = 3000 mg.l-1, using an aerobically stabilized secondary effluent, was studied. Batch cultures were carried out in 2-l glass reactors and in a 30-l glass-fibre carousel reactor. The nutrient removal efficiency as well as biomass production were compared in synthetic mineral medium and in different concentrations of aerobically stabilized piggery effluent. The best performance of Phormidium sp. occurred in diluted stabilized secondary effluent (1:1). Removal efficiencies were 100% for P-PO4(-3), 50% for N-NH4+ and 35% for N-NO3- in small-volume cultures; and 31% for P-PO4(-3), 100% for N-NH4+ and 70% for N-NO3- in an open carousel reactor. Biomass production on the aerobically stabilized effluent was six times higher in the 2-l reactors and 1.7 times higher in the carousel reactor when compared to the synthetic medium.