Efficiency of oil removal from real wastewater with different sorbent materials.

The aim of this paper was to investigate the efficiency of different sorbent materials for oil removal from wastewater. Two types of sorbents were investigated: organic (loose natural wool fibers (NWF) and recycled wool based nonwoven material (RWNM)) and inorganic (sepiolite). Sorption was carried out in continuous tubular contractor (initial oil concentration of 1511 mg/dm(3)) and batch tank (initial oil concentration of 5066 mg/dm(3)). Wool-based sorbents showed higher sorption capacity (5.56 g/g for NWF and 5.48 g/g for RWNM) compared to sepiolite (0.19 g/g) in case of sorption in batch tank. The study on sorption in continuous tubular contractor suggested that volume of oily wastewater strongly affected oil removal. The results indicated that the combination of extractive-gravimetric and FTIR spectrophotometric methods can be recommended for precise determination of oil concentration, being suitable as a controlling tool for oil detection.

Reliability of aspiration biopsy in thyroid nodes: study of 2190 operated patients.

The cytologic finding was negative in 1841 patients; accurate in 1763 (95.8%). Suspicious cytology proved malignant in 82 of 252 patients (32.5%). Positive cytology was accurate in 88 out of 97 cases (90.7%). In 1942 benign goiters, cytology was accurate in 90.8% of patients, false suspicious in 8.7% and false positive in 0.5%; the highest percentage of misdiagnosis was in adenomas (15.8%) and thyroiditis (19.0). In 248 malignant goiters, cytology was accurate in 35.5% of patients, suspicious in 33.1%, and false negative in 31.4%. False-negative cytology was found in 44% of follicular cancers, 22.2% of papillary and medullary, and 12.9% anaplastic. The most frequent false-negative cytologic diagnosis was the adenomatous goiter. The accuracy of cytology was statistically higher in papillary cancers than in follicular (77.8% vs 56.0%), in undifferentiated tumors than in differentiated (83.7% vs 65.0%), and in adenomatous nontoxic goiters than in adenomas, thyroiditis and toxic goiters (80.3% vs 42.7%), 20.1% and 13.4%). Positive preoperative fine needle aspiration biopsy cytology is a worthwhile and reliable finding; it fails in less than 10% of patients. Negative cytology, however, does not exclude malignancy in thyroid nodes; it is false negative in more than 30% of cancers.