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Biomedical subjects

G Nano

Publications and source records attributed to G Nano.

9 recordsLinked to original sources
PubMed2003

Combined slurry and solid-phase bioremediation of diesel contaminated soils.

This work investigates, at a laboratory and pilot-scale, the influence of various operating parameters on the combined slurry and solid-phase bioremediation technique for a diesel contaminated soil. For slurry-phase bioreactors (SPB), it has been found that, as far as famine conditions are attained at the end of the react cycle, a low hydraulic retention time and a low slurry recycle ratio allows for a better utilization of the reactor volume. A 7-day slurry-phase bioreactor treatment has been shown to provide enough contaminant removal allowing the soil drawn from the slurry-phase bioreactors to be fed effectively to the solid-phase bioreactors (SoPB) for completing the soil cleanup. However, an important improvement of the solid-phase bioreactor performance has been found using soil additives, namely sand and surfactants. While the first soil additive improves pile porosity and consequently oxygen diffusion, the latter increases contaminant bioavailability.

Biodegradation, Environmental↗
PubMed2003

Midterm experience with the endovascular treatment of isolated iliac aneurysms.

AIM: The aim of this retrospective, single institution study was to describe our 4-year experience with the endovascular repair of isolated iliac artery aneurysms. METHODS: Between May 1997 and June 2001, 16 patients (15 males; mean age 64+/-9 years), were treated with covered stent grafts. Twelve of the endovascular procedures were performed under epidural and 4 under local anaesthesia. The percutaneous approach was employed in 13 cases and the femoral artery had to be exposed in 3 cases that demanded simultaneous revascularization of the peripheral circulation (n=2) or required a 16 F sheath to employ a Baxter Lifepath stent graft (n=1). The mean size of the iliac aneurysms was 4.5 cm (range 3.5 to 5.2 cm). Four aneurysms involved the hypogastric ostium in absence of any distal neck. RESULTS: All the patients underwent initially successful endovascular treatment of isolated iliac aneurysms and were followed from 3 to 52 months (mean 18 months). No procedural deaths and no acute or late graft thrombosis occurred. The perioperative complications included 1 dissection of the external iliac artery that required a further endovacular procedure and 1 case of endovascular leak fed to the hypogastric artery. A CT scan 4 months later showed spontaneous thrombosis of aneurysm and no further leakage. Two patients had undergone combinated femoro-popliteal arterial bypass. CONCLUSION: In our early clinical experience the use of self-expandable covered stent graft successful treated isolated iliac artery aneurysms. Endovascular repair is a safe and effective technique with good midterm results in patients at standard and high risk.

Angiography↗
PubMed2001

Plasma levels of metalloproteinases-3 and -9 as markers of successful abdominal aortic aneurysm exclusion after endovascular graft treatment.

BACKGROUND: Structural alterations of aortic wall resulting from degradation of matrix proteins by matrix metalloproteinases (MMPs) characterize abdominal aortic aneurysms (AAAs). No studies have compared circulating levels of MMPs after endovascular graft (EVG) exclusion in comparison with open surgical repair (OSR) in patients affected by AAA. METHODS AND RESULTS: An abdominal angiography and CT scan were performed in all patients at the time of enrollment. A spiral CT scan was performed at 6 months to detect presence of endoleaks. MMP-3 and MMP-9 levels were measured before EVG (n=30) and OSR (n=15) treatments and at 1, 3, and 6 months of follow-up by a sandwich ELISA technique. Healthy volunteers (n=10) were used as control subjects. Immunohistochemical staining for MMP-9 and MMP-3 was performed on tissue samples from surgical cases. Both MMP-9 and MMP-3 mean basal levels were significantly higher in patients affected by AAA than in control subjects (32.3+/-20.7 ng/mL for EVG and 28+/-9.9 ng/mL for OSR versus 8.9+/-2.5 ng/mL, 2P<0.05; 18.3+/-9.7 ng/mL and 26.7+/-10.8 ng/mL versus 8.2+/-5.3 ng/mL, 2P<0.001). In the OSR group, both MMP-9 and MMP-3 mean levels decreased after surgery (28+/-9.9 ng/mL at basal versus 14.7+/-6.6 ng/mL at 6 months, 2P<0.001; 26.7+/-10.8 versus 12+/-5.3 ng/mL; 2P<0.001). In the EVG group, a statistically significant difference at 6-month follow-up in MMP-9 and MMP-3 mean plasma values was detected in patients who had endoleakage in comparison with patients without endoleakage (44.3+/-20.7 versus 14.6+/-7.0 ng/mL, 2P<0.005; 25+/-11.5 versus 10.3+/-5.4 ng/mL, 2P<0.005). CONCLUSIONS: After EVG exclusion, MMP-9 and MMP-3 levels decreased to a level similar to that of patients undergoing OSR. In addition, a lack of decrease in MMP levels after EVG exclusion may help in identifying patients who will have endoleakage and consequent aneurysm expansion caused by continuous sac pressurization during follow-up.

Aged↗
PubMed1991

A new tool for sampling airborne isocyanates.

A new sampling system is presented that uses solid sorbent media contained in a tube for the determination of airborne isocyanates (2.4-2.6 toluene diisocyanate, hexamethylene diisocyanate, and 4.4' diaminodiphenylmethane diisocyanate). The method is compared with the National Institute for Occupational Safety and Health (NIOSH) Method P&CAM 5505 (Revision #1). Experimental tests yielded results that were highly concordant with the NIOSH method.

Air Pollutants↗
PubMedDate not supplied

Design guidelines for push-pull ventilation systems through computational fluid dynamics modeling.

Open surface tanks often are used in industrial practice. When harmful substances are involved, control of worker exposure requires the use of a local ventilation system. The push-pull system, among others, involves a jet of air that is blown from one side of the tank and collected by an exhaust hood on the opposite side; this system can save up to 50% of the ventilation air. Several guidelines are available for design of such a ventilation system, mainly based on experimental results. However, their validity is confined inside a narrow operating window. In this work a mathematical model developed based on computational fluid dynamics has been used to extend the validity of the existing guidelines outside the range in which they have been validated, with particular reference to tank width and to the velocity of the air drafts.

Air Pollutants, Occupational↗
PubMedDate not supplied

[Strategies for controlling chemical risk factors in work environments].

The strategy involves an initial phase during which environment characteristics, substances used, apparatus involved and working procedures are investigated. Such information is used to define areas to be monitored, periods of sampling and number of measurements to be performed. The adopted procedure takes into account the results obtained on an interaction basis. The scheme makes use of a decisional criterion based on the one sided tolerance limit (OTL) test in order to estimate risk evaluation trends. Each decision is based on a simultaneous control action on ambient and on men. The procedure minimizes the number of measurements, makes effective use of technical and human resources, reduces decisional errors in establishing engineering techniques and can be readily applied to different situations.

Air Pollutants, Occupational↗