Integrating life cycle assessment and characterisation techniques: A case study of biodiesel production utilising waste Prunus Armeniaca seeds (PAS) and a novel catalyst.

Prunus Armeniaca seed (PAS) oil was utilised as a waste biomass feedstock for biodiesel production via a novel catalytic system (SrO-La2O3) based on different stoichiometric ratios. The catalysts have been characterised and followed by a parametric analysis to optimise catalyst results. The catalyst with a stoichiometric ratio of Sr: La-8 (Sr-La-C) using parametric analysis showed an optimum yield of methyl esters is 97.28% at 65 °C, reaction time 75 min, catalyst loading 3 wt% and methanol to oil molar ratio of 9. The optimum catalyst was tested using various oil feedstocks such as waste cooking oil, sunflower oil, PAS oil, date seed oil and animal fat. The life cycle assessment was performed to evaluate the environmental impacts of biodiesel production utilising waste PAS, considering 1000 kg of biodiesel produced as 1 functional unit. The recorded results showed the cumulative abiotic depletion of fossil resources over the entire biodiesel production process as 22,920 MJ, global warming potential as 1150 kg CO2 equivalent, acidification potential as 4.89 kg SO2 equivalent and eutrophication potential as 0.2 kg PO43- equivalent for 1 tonne (1000 kg) of biodiesel produced. Furthermore, the energy ratio (measured as output energy divided by input energy) for the entire production process was 1.97. These results demonstrated that biodiesel obtained from the valorisation of waste PAS provides a suitable alternative to fossil fuels.

Human and ecological risk assessment of heavy metals in different particle sizes of road dust in Muscat, Oman.

Heavy metal contamination of Hg, As, Cu, Cr, Zn, and Pb was investigated in three different fractions 45, 125, and 200 µm of road dust in Muscat, Oman. Dust samples were collected from three different traffic roads, viz. high, medium, and low based on traffic volume and then sieved individually before they analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). Cu has the highest level among the analyzed metals while the lowest amount was for Hg. Most of the metals in all traffic sites have higher concentration in finer fraction and the concentrations of Cu, Pb, and Zn in HT road dust decreased significantly from finer fraction (45 µm) to bigger fraction size (200 µm). The risks of analyzed heavy metals to the urban ecosystem and human health were calculated by the potential ecological risk index and human exposure model, respectively. Risk index levels of studied metals in the three fractions and roads vary from strong to very strong potential. Hg found to have the greatest contribution in risk index in the three different fractions and roads. The values of risk levels for individual metal contamination in the dust street samples from different roads and fractions were ranked in the following order: Hg > Cu > Pb > Cr > Zn. Ingestion is the main pathway of exposure to road dust particles for both children and adults, followed by dermal contact absorption. The HI for children and adults exposed to 45- and 125-µm particles were higher than exposed to 200-µm particles, which indicated that finer particles tend to have higher non-carcinogenic risk. The non-carcinogenic risks of the studied heavy metals to children and adults are within safe threshold value; however, health risks of Cr, Pb, and Cu were relatively high for children.

Evaluation of the safety of primary metabolites of cyadox: Acute and sub-chronic toxicology studies and genotoxicity assessment.

Cyadox (CYA) is a synthetic antimicrobial agent, belonging to quinoxaline (QdNO) family. Cy1 (bidesoxy cyadox), Cy2 (N4-desoxycyadox) and Cy10 (N1-desoxycyadox) are the primary metabolites of CYA. In our present study, an acute toxicity test, a sub-chronic toxicity test, and a battery of three genotoxicity tests were carried out according to standard protocols. The LD50 of the metabolites were above 5000 mg/kg b.w. The maximum tolerated dose (MTD) of Cy1 and Cy-M (mixture of Cy2 and Cy10) in rats, and the MTD of Cy1, Cy2 and Cy10 in mice were above 6000 mg/kg b.w./day. In subchronic study, rats were separately administered Cy1 and Cy-M at the dose levels of 0, 50, 150 and 2500 mg/kg diet for 90 days, with CYA (2500 mg/kg) as a control. Significant decreases in body weight and changes in clinical serum biochemistry were observed in the high-dose group of Cy1 and Cy-M, as well as CYA. Significant changes in relative weights of organs at 150 and 2500 mg/kg diet of Cy1 and CYA were noted. Additionally, the high-dose groups of Cy1, Cy-M and CYA showed pathological changes near the hepatic portal area. There was no evidence for genotoxic activity of any of the three metabolites in the bacterial reverse mutation test, mouse bone marrow micronucleus assay or an in vitro assay for clastogenicity. Based on the subchronic study, the target organ of the primary metabolites was the liver, and the no-observed-adverse-effect level for Cy1 and Cy-M was 150 mg/kg diet.

Three-Dimensional Echocardiographic Assessment of Aortic Dissection.

In the present study, we report our experience of using three-dimensional reconstruction of transesophageal two-dimensional echocardiographic images in the assessment of aortic dissection (22 patients), aortic rupture (1 patient), aortic aneurysm without dissection (2 patients), and aortic tumor (1 patient).