Value-added products from wastewater reduce irrigation needs of Arundo donax energy crop.

Irrigation restrictions due to drought periods related to climate change, would affect different crops, especially to non-food crops. In this regard the effect of irrigation reduction should be studied in energy crops in order to obtain a sustainable bioenergy cropping system. Arundo donax, has been considered a crop with high water requirements, it has nevertheless been proven to be drought tolerant. However, there is a lack of knowledge on the effect of reduced irrigation combined with the use of different fertilizers. This work studied the combined effect of value-added products (VAPs) from wastewater (treated sewage sludge) or traditional inorganic fertilizers, and irrigation reduction in Arundo donax crop in a 2-year pot experiment. Plant biometric characteristics, chemical properties and biomass yield were studied as well as the effect of treatment on soil properties. Results showed that under reduced irrigation conditions, biomass production was reduced, especially during the second year. Organic treatments from sewage sludge minimize the effect of irrigation reduction. In these treatments, biomass yield for reduced irrigation was similar to that of the control treatment with irrigation at field capacity. For this reason, it is recommended to use VAPs from wastewater as organic amendments enabling water restriction with lower effect on Arundo production.

Assessing Arundo donax L. in vitro-tolerance for phytoremediation purposes.

Phytoremediation using high production crops could be an alternative for the recovery of metals polluted soils. In this sense, the Arundo donax L. energy crop has shown tolerance to moderate concentrations of heavy metals. The objective of this work was to test the tolerance of micropropagated plants of Arundo donax to increasing concentrations of cadmium, chromium, cooper, nickel and lead, in an in vitro culture medium. Biomass production and concentration of heavy metal in shoots and roots were analyzed. Results showed that heavy metals were accumulated mostly in subterranean organs. The increase in heavy metal concentration was dose dependent and not always follows a linear relationship. Arundo donax showed a broad tolerance to cadmium (0.5 mM), chromium (0.2 mM), cooper (2 mM), nickel (0.5 mM) and lead (1 mM). In relation to cooper, Arundo donax showed a hyperaccumulative potential. These results suggest the potential use of Arundo donax in the phytomanagement of polluted soils although further studies should be carried out using polluted soils.

Clinical Evaluation of All Ceramic Zirconia Framework Resin Bonded Bridges.

OBJECTIVE: To evaluate the clinical longevity of 58 adhesively bonded single unit yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic Resin Bonded Bridges (RBB). MATERIALS AND METHODS: Twenty six consecutive patients with at least one congenitally missing tooth in the maxilla or mandible were provided with 58 single unit Y-TZP RBBs. The cantilever RBBs were designed and milled using a CAD-CAM system to produce frameworks which were veneered using a glass-ceramic material and cemented with a self-etching dual-cure resin cement. RESULTS: Following a mean follow up period of 36.2 months (maximum 62.3 months, minimum 25.4 months), 48 restorations remain in service with a survival rate of 82.7%. One anterior retainer fracture was encountered and no fractures of the posterior framework or ceramic were noted within the time frame reported. CONCLUSIONS: All ceramic Y-TZP RBBs replacing maxillary and mandibular teeth in the anterior and posterior areas demonstrated an 82.7% Kaplan Meier survival rate over 3 years, which was comparable to previously published survival rates for the non-perforated metal framework RBBs. CLINICAL IMPLICATIONS: Replacement of anterior or posterior teeth using single unit cantilevered RBBs using Y-TZP ceramics should be considered a viable restorative option with a high survival rate.

Indoor air quality impacts of ventilation ducts: ozone removal and emissions of volatile organic compounds.

The concentrations of contaminants in the supply air of mechanically ventilated buildings may be altered by pollutant emissions from and interactions with duct materials. We measured the emission rate of volatile organic compounds (VOCs) and aldehydes from materials typically found in ventilation ducts. The emission rate of VOCs per exposed surface area of materials was found to be low for some duct liners, but high for duct sealing caulk and a neoprene gasket. For a typical duct, the contribution to VOC concentrations is predicted to be only a few percent of common indoor levels. We exposed selected materials to approximately 100-ppb ozone and measured VOC emissions. Exposure to ozone increased the emission rates of aldehydes from a duct liner, duct sealing caulk, and neoprene gasket. The emission of aldehydes from these materials could increase indoor air concentrations by amounts that are as much as 20% of odor thresholds. We also measured the rate of ozone uptake on duct liners and galvanized sheet metal to predict how much ozone might be removed by a typical duct in ventilation systems. For exposure to a constant ozone mol fraction of 37 ppb, a lined duct would initially remove approximately 9% of the ozone, but over a period of 10 days of ozone removal efficiency would diminish to less than 4%. In an unlined duct, in which only galvanized sheet metal is exposed to the air-stream, the removal efficiency would be much lower, approximately 0.02%. Therefore, ducts in ventilation systems are unlikely to be a major sink for ozone.