A buffer value index to evaluate effects of buffers on ruminal milieu in cows fed high or low concentrate, silage, or hay diets.

Our objective was to develop a buffer value index that would incorporate alterations in both ruminal fluid pH and buffering capacity as indicators of the influence of dietary buffering and alkalinizing agents on ruminal acid-base status. This index was evaluated using ruminal fluid from four lactating Holstein cows fed either sorghum silage or alfalfa hay in high or low concentrate diets. Ruminal fluid was incubated in vitro for 1, 2, 3, 4, or 5 h with no buffer or with 7.1 g of either NaHCO3, sodium sesquicarbonate, or a multielement buffer added per liter of ruminal fluid. Ruminal fluid pH was lower for diets based on high concentrate or alfalfa; buffering capacity between pH 5 and 7 was greater for high concentrate diets but was not affected by forage type. Ruminal fluid pH was higher for sesquicarbonate than for NaHCO3, the multielement buffer, or the control; however, ruminal fluid H+ concentration was similar between sesquicarbonate and NaHCO3, and both were lower than for the multielement buffer. Hydrogen ion concentration for the multielement buffer was lower than for the control. Buffering capacity was highest for NaHCO3, followed by sesquicarbonate, the multielement buffer, and the control. The buffer value index, which accounted for alterations in both H+ concentration and buffering capacity, was highest for NaCHO3, followed by sesquicarbonate, the multielement buffer, and the control. The poor response to the multielement buffer may be attributable to our relatively short incubation interval (less than 5 h). Dietary buffers increase both ruminal fluid pH and buffering capacity; both of these responses are beneficial.(ABSTRACT TRUNCATED AT 250 WORDS)     

A hydrogen-based variable-gain controller for anaerobic digestion processes.

An easy-to-implement controller based on gas phase measurements for anaerobic digestion processes was developed. The controller is based on the indirect control of COD in the effluent by means of controlling the hydrogen concentration in the biogas. The fast response of hydrogen under destabilizations, such as those caused by overloads, guarantees an early actuation on the system before it destabilizes. The controller is designed such that it brings the anaerobic digestion process to maximum capacity by pushing it to maximum methane production as long as hydrogen remains low. Experiments have been conducted to test the controller under organic over- and underload situations and promising performance was achieved. Further experiments must be carried out to validate the controller under a wider spectrum of situations to enable its robust industrial application.     

Evaluation of biodiesel as bioremediation agent for the treatment of the shore affected by the heavy oil spill of the Prestige

The efficiency of different bioremediation products (nutrients, microorganisms and biodiesel) was tested using tiles located in both the supra-littoral and intertidal zones of a beach that was affected by the heavy oil spill of the Prestige. Neither nutrients nor microorganisms meant an improvement with respect to the natural processes. The addition of biodiesel improved the appearance of the treated tiles and apparently accelerated the degradation of the aliphatic and aromatic fractions of the residual fuel oil. Nevertheless, PAHs degradation was similar and very high in all the treatments (80-85% after 60 days). On the other hand, the evolution with time of the amount of vanadium was similar to that of 17alpha(H),21beta(H)-hopane, so it was concluded that vanadium could also be used to estimate the extent of oil degradation in the field. These results also suggested that the residual fuel oil mineralization was very low throughout 1 year in all the treatments. Moreover, the increase of the oxygen content of the residual oil from around 1% till 4-8% indicated that the partial oxidation of hydrocarbons took place, and that the hydrocarbon oxidation products accumulated in the polar fractions. In general, the results pointed out that bioremediation techniques were not suitable for the recovery of shores affected by heavy oil spills.     

The induction and expression of IgA anti-DNP antibodies in rat bile and secretions

Pregnant rats were immunized with dinitrophenylated type III-pneumococcal vaccine by the intravenous, gastric, or intramammary routes. Anti-DNP antibody responses in the IgA, IgG and IgM isotypes were measured in serum, secretions and bile. Gastric intubation was most effective at eliciting IgA antibody responses in bile and secretions, whereas the other routes were more effective at inducing IgG responses in serum and bile. IgM antibody responses were infrequent and were found in fluids most closely associated with the immunization route. Isoelectric focusing studies of IgA antibodies appearing in secretions and bile revealed that the gastric route consistently elicited antibody spectrotypes with shared components. Intravenous and intramammary immunization resulted in IgA spectrotypes possessing less homology, suggesting that these protocols lead to independent antibody responses triggered in spleen, draining lymph nodes, or secretory sites. After gastric stimulation, the appearance of IgA antibodies with identical spectral components in secretions and bile favours the concept that IgA precursor cells with identical clonotype potential migrate from the gastrointestinal area to secretory sites. Antibody expression in bile appears to result from the selective transfer of IgA populations gaining access to serum after synthesis at a secretory site.     

Changes in serotonin level and turnover in discrete hypothalamic nuclei after pinealectomy and melatonin administration to rats

OBJECTIVE: It has previously been shown that 17 beta-oestradiol (E2) implants counteract the formation of more acidic isoforms of the gonadotrophins in post-menopausal women. A much lesser effect was observed on the charge of the gonadotrophin isoforms in women with chronic oral daily therapy with 2 mg E2 combined with a progestogen, 1 mg norethisterone acetate (NETA), in spite of similar serum levels of E2 and SHBG. The presence of the progestogen in the latter study may explain the difference observed. The present study investigated the effect of the progestogen NETA on the charge and concentration of serum FSH and LH in E2 implant treated women. DESIGN: A group of 8 post-menopausal women, mean age 65 years (range 50-80 years) treated with 20 mg E2 implants every 6 months, participated in the study. The women were given a daily oral medication of 5 mg NETA for a 4-week period starting at 4 weeks after the insertion of an E2 implant (mean serum E2 420 pmol/l). This treatment with NETA was repeated in 6 of the women starting at 18 weeks after the insertion of the E2 implant (mean serum E2 317 pmol/l). Blood samples were obtained at the start of the NETA therapy, after 2 and 4 weeks of treatment and at 4 weeks after the last NETA treatment. The effects of NETA therapy on the charge of the serum gonadotrophin isoforms was determined by electrophoresis in 0.1% agarose suspension and FSH, LH, E2, and SHBG were determined with fluoroimmunoassays. RESULTS: The NETA treatment decreased the serum FSH and LH levels after 2 weeks to 24 and 23% of the levels before NETA and after 4 weeks to 14.6 and 8.8%, which were 1.3 and 2.2% of the mean levels for non-treated post-menopausal women. Both FSH and LH isoforms became more acidic during the first 2 weeks of treatment. During the following 2 weeks of NETA treatment the isoforms of both FSH and LH became more basic again. Ten weeks later both the concentration and the charge of the gonadotrophins were similar to those before the NETA treatment. The changes in concentration and charge of the gonadotrophins during the second treatment period were similar to those during the first. All the changes were statistically significant (P < 0.05 - < 0.001). The mean SHBG level decreased (P < 0.01) from 84.5 to 70.6 nmol/l after 2 weeks and to 59.9 nmol/l after 4 weeks of NETA treatment and increased (P < 0.01) 10 weeks later to 77 nmol/l. CONCLUSION: In the oestradiol treated women, the effect of the progestogen norethisterone acetate on the charge of the gonadotrophin isoforms was time-related. The oestradiol effect on the charge was counteracted during the first 2 weeks of progestogen treatment and more acidic isoforms appeared in the circulation. During the following 2 weeks the isoforms became more basic again. The levels of the gonadotrophins were efficiently decreased after 2 weeks of progestogen treatment and further decreased after 4 weeks. The time-related effect of the progestogen on the gonadotrophin isoforms may be mediated via changes in the pattern of GnRH release from the hypothalamus. The observed gradual decrease in the SHBG level during the progestogen therapy may cause an increased oestradiol effect on the hypothalamus and pituitary.     

Long chronic course of hemiparkinson-plus with l-dopa maintained response

OBJECTIVE AND CLINICAL CASE: We describe and present a video film of a patient with a hemiparkinsonian illness associated with hemidystonia and pyramidalism, which responded to continuous L-Dopa treatment for twenty years, with no fluctuation or deterioration at the end of the dose-effect. CT and MR studies were normal. CONCLUSIONS: The characteristics of this case with probable static unilateral dysfunction, basically presynaptic, of the nigrostriate via, make it reasonable to include it in the hemiparkinson-hemiatrophy group.     

Low urinary dopamine excretion associated to low sodium excretion in normotensive Piaroa Amazonian ethnia compared to urban subjects

The objective of this work was to compare urinary dopamine, noradrenaline, adrenaline, sodium and potassium excretion in a group of normotensive Piaroa Amazonic ethnia who do not use salt in their regular food intake, against a group of urban normotensive citizens known to have a high salt intake in their regular meals. Twenty adult normotensive Piaroa subjects living in the Amazonas forest, 11 men and 9 women, 23-72 years old, and 33 normotensive urban citizens, 25-70 years old, 17 men and 17 women, were included in the study. After a 10 min. rest, an average of three supine systolic (SBP) and diastolic (DBP) blood pressure recordings was obtained. Piaroas subjects SBP and DBP were 111.3 +/- 2.9 mmHg and 62.7 +/- 1.9 mmHg respectively; urban subjects SBP and DBP were 111.8 +/- 2.2 mmHg and 70.3 +/- 1.6 mmHg respectively. Supine heart rate was lower in Piaroas (58.0 +/- 1.8 beats/min) than in urban subjects (76.5 +/- 1.9 beats/min), p < 0.05. Sodium urinary excretion was much lower in Piaroas (12.6 +/- 5.2 mmol/24 h) when compared to urban subjects (210.7 +/- 24.5 mmol/24 h), p < 0.01. No difference was found in daily urinary potassium excretion between Piaroas and urban subjects (50.4 +/- 7.2 mmol/24 h vs 45.1 +/- 7.4 mmol/24 h). Urinary dopamine excretion was lower in Piaroas (314.7 +/- 40.1 micrograms/24 h) in comparison to urban subjects (800.4 +/- 59.2 micrograms/24 h), p < 0.05. Daily urinary noradrenaline and adrenaline excretion were 67.9% and 85.4% respectively lower in Piaroas than in urban subjects. In conclusion, lower amounts of sodium daily intake are associated to lower kidney dopamine production in Piaroas as compared to urban subjects. Apparently indigenous tribes might require less kidney dopamine synthesis to excrete the very small amounts of salt they consume in their regular food intake. The opposite was found in urban subjects; more kidney dopamine synthesis would be required for larger amounts of urinary sodium excretion. In this population, essential hypertension has been associated to a failure of the natriuretic mechanism triggered by dopamine onkidney tubules.     

Characterizing conflicts in fair division of indivisible goods using a scale of criteria

We investigate five different fairness criteria in a simple model of fair resource allocation of indivisible goods based on additive preferences. We show how these criteria are connected to each other, forming an ordered scale that can be used to characterize how conflicting the agents’ preferences are: for a given instance of a resource allocation problem, the less conflicting the agents’ preferences are, the more demanding criterion this instance is able to satisfy, and the more satisfactory the allocation can be. We analyze the computational properties of the five criteria, give some experimental results about them, and further investigate a slightly richer model with \(k\)-additive preferences.     

Nitrification in saline wastewater with high ammonia concentration in an activated sludge unit

A nitrifying activated sludge reactor fed with a high salinity medium was operated efficiently at ammonia loading rates between 1 and 4 g NH4+ -N l(-1) d(-1). The system became completely inefficient at inlet salt concentrations higher than 525 mM due to the mixed inhibition effect of salts and ammonia. The final product was mainly nitrate although dissolved oxygen limitations caused sporadic ammonia and nitrite accumulations. Specific nitrifying activity decreased due to the saline effect. A set of activity tests showed that in the continuous reactor non-adapted biomass is rather more sensitive than biomass to the saline effect. Physical properties of biomass in the reactor (sludge volumetric index and zone settling velocity) were not affected by the saline concentration, a biomass concentration of 20 gVSS l(-1) was achieved.