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M M Gonçalves

Publications and source records attributed to M M Gonçalves.

8 recordsLinked to original sources
PubMed2001

Anaerobic sulphate-reducing microbial process using UASB reactor for heavy metals decontamination.

This study was conducted to investigate the possibility of using sewage as an organic substrate for the growth of sulphate reducing bacteria (SRB) and to acclimatise anaerobic sludge to produce sulphide from sulphate reduction, with a view to metal precipitation. The experiments were carried out in a continuous bench-scale bioreactor (13 1 UASB reactor) operated with hydraulic retention times (HRT) of 11 and 19 hours. The feed solution used was composed of the liquid part of the sewage (organic matter) supplemented with nickel sulphate and sodium sulphate. The results showed that it was possible to acclimatise anaerobic sludge for production of sulphide by sulphate reduction. A relation between the available COD and the concentration of sulphate reduced by SRB was observed. High nickel removal efficiency (96%) was obtained during the whole operation (320 days). However, the process required very strict control of the organic load available (sewage) in the solution and, if necessary, the addition of a complementary organic carbon source, in order to maintain a constant level of metal removal. The SRB were not affected by the HRT values studied and were installed and maintained in the system; however, granular sludge was not observed. The micrographs confirmed the presence of iron and nickel sulphides and also a mixed bacterial culture in the anaerobic sludge. The EDS spectrum of the sludge showed that nickel was retained in the sludge predominantly as a nickel sulphide.

Bacteria, Anaerobic↗
PubMed2001

[Abundance and infection of Biomphalaria glabrata with Schistosoma glabrata in the state of Rio de Janeiro, Brazil].

OBJECTIVES: To investigate the spatial distribution, abundance and natural schistosomiasis infection levels in the snail Biomphalaria glabrata, the intermediate host of Schistosoma mansoni in an area of the State of Rio de Janeiro, Brazil. METHODS: In the Pamparrão area, Sumidouro county, RJ, Brazil, snail captures were carried out every other month from June 1991 to November 1995. There were 23 collecting sites along the Pamparrão stream and its three tributaries (A, B and C). Captured snails were examined in the laboratory for infection. Data analyses were performed using Spearman coefficient (0.5% significance level) and Qui-square test. RESULTS: The abundance of B. glabrata was variable in both time and space. Most of the collection sites showed a negative correlation with rainfall. The tributary B had the highest and most steady infection rates (more than 25% in some sites). There were found significantly more infected snail in the dry season (chi2 = 20.08; p=0.001). CONCLUSIONS: B. glabrata population in the Pamparrão valley was negatively influenced by rainfall, especially at the Pamparrão stream. The dry season seems to promote the infection probably due to the lower water volume, increasing the chance of interaction between the intermediate host and the parasite.

Animals↗
PubMed1996

Biological treatment of a synthetic gold milling effluent.

This paper reports on biological sludge acclimatisation and the results concerning the removal of free cyanide, thiocyanate and metallocyanides (copper, iron and zinc) from a synthetic gold milling effluent. The experiments were carried out in a continuous bench-scale bioreactor, and the experimental set-up consisted of two identical units, one of which served as control. The acclimatisation of the biomass was based on a stepwise procedure, in which the proportion of synthetic solution in the influent was gradually increased. The reactors were fed with a mixture of synthetic effluent and sewage, and the treatment efficiency was evaluated through the monitoring of the following parameters: chemical oxygen demand (COD), free cyanide, thiocyanate, copper, iron and zinc concentrations. A well adapted microbial consortium was obtained at the end of the acclimatisation period, which was able to remove more than 95% of free cyanide, thiocyanate, copper and zinc, originally found in the influent. These removal efficiencies were obtained when the reactor was operated with a hydraulic retention time (HRT) of about 8 h. The performance results of experiments carried out with lower HRT (5 h) and higher dissolved oxygen (DO) concentration (6.5 mg litre(-1)) are also presented and discussed in this study.

Journal Article↗
PubMed1993

[Neurologic evaluation of 118 patients in the first postoperative period of cardiovascular surgery].

118 patients (79 mean and 39 women, mean age of 50.7 years) who underwent cardiovascular surgery and extracorporeal oxygenation were prospectively evaluated for neurologic complication and its correlation with risk factors. 71 were submitted to coronary artery graft by-pass (RM), 18 to valve replacement (TV), 6 to prosthetic valve replacement (RV), 11 to commissurotomy(Co), 5 to thoracic aortic aneurysm correction (An Ao T) and 7 to other surgeries (OT). All of them received extracorporeal oxygenation. No deaths were registered; 14 (11.9%) patients had neurologic abnormalities: delirium in 7 cases, ischemic stroke in 6, epileptic seizure in 3. Patients with systemic arterial hypertension and older patients exhibited a statistically significant (p < 0.05) higher risk of complication. Compared to data of the literature, we had a lower index of morbidity and mortality.

Adolescent↗
PubMed1989

Alterations in the fatty acyl composition of plasma cholesteryl esters in Brazilian patients with hepatosplenic schistosomiasis mansoni.

1. The dyslipoproteinemia commonly occurring in the hepatosplenic forms of schistosomiasis mansoni in Brazilian patients is characterized by low plasma levels of cholesteryl esters and of the cholesterol-esterifying enzyme, lecithin:cholesterol acyltransferase (LCATase, EC.2.3.1.43). 2. In the present study, normal healthy individuals and patients suffering from hepatosplenic schistosomiasis mansoni were compared for the fatty acyl compositions of circulating plasma cholesteryl esters and of those formed in vitro by the action of LCATase on a) the endogenous plasma lipoproteins and b) an excess of lipoprotein substrate composed of heat-inactivated plasma. 3. In patient plasma the proportions of saturated and monounsaturated cholesteryl esters were higher and those of diunsaturated and polyunsaturated esters were lower than in the control group. 4. Similar differences were observed between patients and controls in the proportions of the cholesteryl ester subclasses formed in vitro by the action of LCATase on endogenous plasma lipoproteins. 5. Incubation of fresh normal or patient plasma with excess heat-inactivated plasma as substrate for LCATase produced proportions of cholesteryl ester subclasses similar to those formed during incubation of nonheated aliquots of the appropriate substrate plasma. 6. We conclude that the alterations in fatty acyl composition of plasma cholesteryl esters in patients with hepatosplenic schistosomiasis mansoni do not appear to be a direct consequence of the low levels of LCATase activity in patient plasma.

Adult↗