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G Ricco

Publications and source records attributed to G Ricco.

86 records · Page 5Linked to original sources
PubMedDate not supplied

Treatment options for tannery wastewater. I: Alkalinization with or without post-ozonation.

This is the first of two papers each dealing with a specific technological option for replacing the Fenton's reagent with simpler processes for treating industrial wastewater. In particular, the paper reports the results of an investigation aimed to check, at lab scale, the effectiveness of a chemical process (i.e., alkalinisation with or without post-ozonation) for treating tannery wastewater whose residual COD, measured after conventional biological treatment, result still higher than the Italian COD Maximum Allowable Concentration (MAC) value (i.e., 160 mgO2/L). The results have demonstrated that when the value of residual COD lies in the range 200 divided by 250 mgO2/L, a simple alkalinisation with NaOH, up to pH 12.5, allows to reach the MAC value with an alkali consumption equivalent to the acid consumption required by the Fenton treatment and with a chemical sludge production significantly lower, i.e. approximately 0.7 kg(dry)/m3 instead of approximately 1.5 kg(dry)/m3. Conversely, when the value of the residual COD lies in a higher range (i.e. 300 divided by 350 mgO2/L), in order to reach the COD MAC value, alkalinisation (from pH 8 to pH 12.5) must be followed by an ozonation post-treatment. From the chemical stand point, the paper clearly demonstrates that analyzing only simple "gross parameters" (i.e., TSS, TOC, COD, BOD5 and EC20) it is possible to get useful information about the chemical properties of the organic pollutants occurring in tannery wastewater.

Hydrogen Peroxide↗
PubMedDate not supplied

Molecular characterization and functional studies on Hb Kempsey, beta 99 (G-1) Asp----Asn, a high-oxygen affinity variant.

BACKGROUND: Hb Kempsey (beta 99 Asp----Asn) is a high-oxygen affinity hemoglobin, never before reported in Italy, associated with secondary erythrocytosis. It has been found in the heterozygous state in two subjects from the same family originating from the Verona area in Northern Italy. METHODS: The abnormal hemoglobin was studied both at the protein and at the DNA level. The amino acid substitution was identified by fingerprinting and amino acid analysis. The nucleotide replacement was investigated by means of polymerase chain reaction (PCR) of the beta gene and direct sequencing. Oxygen affinity and other functional parameters were assessed on whole blood and on the separate hemoglobin fractions. RESULTS: These studies allowed us to establish the molecular substitution GAT (Asp)----AAT (Asn) at codon 99. Functional studies revealed a left-shifted and biphasic dissociation curve of the proposita, with a very low p50. The two carriers of this hemoglobinopathy have different degrees of polyglobulia, since iron deficiency in one of them reduces total and abnormal Hb. CONCLUSIONS: The compensatory mechanisms for tissue hypoxia are discussed with the conclusion that erythrocytosis has to be preserved in these patients to maintain adequate tissue oxygenation.

Aged↗
PubMedDate not supplied

[Pindborg tumor or odontogenic calcifying epithelial tumor. A clinical case].

Calcifying epithelial odontogenic tumour (CEOT) is an uncommon odontogenic neoplasm first recognized as a distinct entity by Pindborg in 1955. One of the frequent histological findings is the occurrence of amorphous deposits of so called amyloid like material within the tumour. A case of this tumour is reported in a 75 years woman.

Aged↗
PubMedDate not supplied

Catalase against met-Hb excess during oximetries of dilute Hb-A samples.

Functional parameters of diluted Hb-A have been determined before and after addition of catalase and disodium-EDTA to the samples. There are no important differences between the results drawn from catalase added samples and catalase free ones, except for the fact the met-Hb level at pH 7.8 is significantly lower in the samples containing catalase. On the contrary, catalase is almost ineffective against met-Hb at pH 6.8, whereas its activity at pH 7.3 is rather modest. Another limitation is that catalase remains active against met-Hb for not more than 15-20 minutes after addition to the sample, which is just the time necessary for one complete (manual) oximetry.

Catalase↗
PubMedDate not supplied

Use of an enzymatic mixture against met-Hb excess during oximetry of dilute Hb-A solutions.

A mixture of NADH, cytochrome-C-reductase and methylene blue was employed to antagonize ferri(met)-Hb formation during oximetries of dilute samples of human Hb-A. Its efficacy is clear at any pH between 6.8, 7.3 and 7.8, in the presence of 100 mM NaCl. In these cases, ferri(met)-Hb decreases of about 2/3, compared with the enzyme-free controls, and p50 increases. On the contrary, when samples are examined at pH 7.3 with 600 mM NaCl and/or 100 mM NaCl plus 1 mM DPG, ferri(met)-Hb of the samples containing the enzymes also decreases, but not more than 1/2 of its initial value, whereas also p50 decreases. Finally, Bohr effect is lower in the samples containing the enzymes. In conclusion, the enzymatic mixture is very useful, but not easy to be handled; so, some observations for its correct use are required.

Adult↗