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F Acevedo

Publications and source records attributed to F Acevedo.

2 recordsLinked to original sources

Theoretical conversion yields for penicillin synthesis.

The efficiency of conversion of the carbon-energy source to product is of primary importance in many fermentation processes. In order to assess the efficiency of a process, one must know how close the actual conversion yield is to the theoretical maximum. Theoretical conversion yields are useful, therefore, as guides in improving a process. This knowledge is particularly important today because the cost of raw materials is rapidly rising. In this study, the biochemical pathway of penicillin synthesis was used to estimate the theoretical yield of penicillin from glucose, ammonia, and sulfate. These values are compared with experimental data from the literature. An analysis of the role of glucose in the synthesis of cell mass and penicillin and in the maintenance of cells makes it possible to assess the efficiency of carbon-source utilization and to direct further advances in penicillin fermentations.

Ammonia

[Use of esophageal cytology. Comparative study on the value of various methods (III)].

Several esophageal cytologic tecniques (sponge biopsy, sponge smear, and espohageal washings) were assessed and compared with endoscopy and biopsy of esophageal tumors. Esophageal cytology rendered better results than esophagoscopy or biopsy, with a 97% positivity in cases of esophageal carcinoma, when using sponge biopsy and sponge smear techniques, and of 91.4% for esophageal and gastric carcinoma of the fundus invading gastroesophageal junction, when considered together. The combination of sponge techniques was better for diagnosisng esophageal carcinoma than the application of esophageal washings, a more difficult, time consuming, and sometimes unfeasible method. However, the utilization of three mehtods enhanced the overall diagnostic possibilities in all cases of esophageal tumors when considered together.

Biopsy