The role of zeolites in wastewater treatment of printing inks.

The adsorption of residual organic pollutants from flocculated printing ink wastewater onto several synthetic zeolites was investigated as a finishing method for additional reduction of TOC. The nonselective removal of total organic content was studied. The amount of adsorbed organics was largest for ZSM-5 and NH4-Beta while the other zeolites studied showed lower efficiency, suggesting that adsorption is independent of pore structure. The adsorption rates of organic pollutants were fast. Although the TOC removal increases with increasing amount of zeolite, because of the necessity of additional filtration to lower turbidity to required levels, 5.0 g/L of zeolite was found to be optimum. The 88% reduction of TOC obtained with a single flocculation treatment was improved with the combination of flocculation and adsorption with ZSM-5 which resulted in the overall TOC efficiency of 95%. The addition of zeolites in decantated supernatant water, obtained after flocculation, was also studied in order to assess the effect of floc on zeolite capacity. A decrease in adsorption capacity occurred only if a coagulant concentration less than optimal was applied. Removal efficiency then decreased by around 10%. It was concluded that flocculation followed by adsorption with zeolites is an effective treatment method for this kind of wastewater.

Three-dimensional CT reconstruction and volume measurements of the pharyngeal airway before and after maxillofacial surgery in obstructive sleep apnea.

We believe that maxillofacial surgery is a successful procedure for treatment of sleep apnea, provided the patients are fully assessed pre-operatively with nocturnal polysomnography and pharyngeal airway imaging. Long follow-up is also necessary to evaluate success.

Effect of nasal dilation on snoring and apneas during different stages of sleep.

This study was designed to test the hypothesis that nasal dilation reduces snoring. To achieve this we performed nocturnal polysomnography, including measurement of snoring, in 15 patients without nasal pathology before and after insertion of a nasal dilator (NOZOVENT). Snoring was quantified for each sleep stage by recording the number of snores per minute of sleep, number of snores per minute of snoring time and nocturnal sound intensities (maximum, average and minimum). We found that nasal dilation had no effect on the number of apneas, hypopneas or oxygen saturation. Snoring parameters were unaffected by NOZOVENT during stages I, II and REM sleep, but were all significantly reduced during slow wave sleep. We conclude that dilation of the anterior nares in patients without nasal pathology has a relatively weak effect on snoring, and routine use of nasal dilating appliances is not recommended for treatment of snoring.

Nasal airway dilation and obstructed breathing in sleep.

Nasal respiratory airflow resistances of awake snorers averaged 0.188 +/- 0.165 Pa/cm3/s (N = 306) and were not elevated beyond the normal range (less than 0.25 Pa/cm3/s). Resistances were decreased substantially from a mean of 0.164 +/- 0.128 to 0.065 +/- 0.037 Pa/cm3/s (N = 72) by a nasal vestibular dilator (Nozovent). Effects of the dilator on breathing disorders in sleep were determined by polysomnographic recordings that included frequency, duration and intensity of snoring, apneas, hypopneas, and oxygen saturation in 10 heavy snorers while asleep with and without the dilator in situ over periods of several hours. No significant changes were detected in these parameters in any stage of sleep.

Resolution of obstructive sleep apnea following facial surgery.

Compared to uvulopalatopharyngoplasty (UPPP), maxillo-facial surgery is rarely performed in Canada for treatment of obstructive sleep apnea. However, in patients with retrolingual obstruction, UPPP cannot be expected to result in good surgical outcome. We describe a patient with retrognathia causing airway obstruction at the base of the tongue, in whom sagittal mandibular osteotomy with hyoid bone advancement resulted in resolution of snoring and sleep apnea.

Site of airway obstruction in patients with obstructive sleep apnea before and after uvulopalatopharyngoplasty.

This study describes a simple method, based on a movable catheter technique, for use during routine polysomnography to identify the site of obstruction, and this has been applied to 51 patients with suspected sleep apnea. The obstruction was found to be retropalatal in 30, retrolingual in 7, and could not be determined in 14 patients (12 had no sleep apnea, 1 did not sleep, and 1 had central sleep apnea). Twelve of these patients had uvulopalatopharyngoplasty with preoperative and postoperative polysomnograms to determine the site of obstruction. The preoperative obstruction was retropalatal in nine and retrolingual in three. Postoperatively, four patients (one with retrolingual obstruction and three with retropalatal obstruction) no longer had sleep apnea. In the remaining eight patients, the site of obstruction was unchanged from the preoperative one. Several conclusions result: 1. the movable catheter technique offers a simple way to determine the site of obstruction in patients with significant obstructive sleep apnea, 2. most such patients obstruct in the retropalatal region, and 3. preoperative localization of the site of obstruction to the retropalatal region does not seem to improve the surgical outcome of uvulopalatopharyngoplasty.

Snoring, apnea and nasal resistance in men and women.

To examine if gender and airway resistance (nasal and pulmonary) influence the loudness and intensity of snoring, we prospectively studied 370 unselected patients referred to our sleep clinic because of heavy snoring and a possibility of sleep apnea. All patients had full nocturnal polysomnography, including measurements of snoring using a calibrated microphone-sound meter system, and determination of pulmonary (Raw) and nasal resistance (Rna). Snoring was quantified by reporting the number of snores per hour of sleep (snoring index--SI) and the maximum nocturnal sound intensity (dBmax). The patient population comprised 77 females and 293 males, ranging in age from 12 to 80 years. Based on the apnea/hypopnea index (AHI) we separated all patients into the apneic and non-apneic groups. There were 201 non-apneic snorers (AHI less than or equal to 10) and 160 apneic snorers (AHI greater than 10). There was no significant difference in snoring frequency, maximum nocturnal sound intensity, nasal and pulmonary resistance between men and women or between apneic and non-apneic snorers. Stepwise, forward, multiple linear regression analysis showed that body mass index and nasal resistance correlate significantly with the snoring index (R2 = 0.29, p less than 0.005), while age and body mass index correlate only weakly, but significantly, with the maximum nocturnal sound intensity. We conclude that (1) men snore similarly to women, and (2) obesity and nasal resistance are important determinants of the frequency of snoring. It follows that measures taken to reduce weight and decrease nasal resistance may be of benefit in reducing snoring.