Identification of Commercial Oxo-Biodegradable Plastics: Study of UV Induced Degradation in an Effort 1 to Combat Plastic Waste Accumulation

About 50% of plastics is discarded after only single use which creates major environmental burdens. End of life 14 single-use items such as carrier bags constitute a large proportion of the litter found in marine and terrestrial 15 environments alike. The main objective of the current work was to investigate the response of an oxo-16 biodegradable commercial plastic film product to photo-degradation using accelerated weathering, verifying the 17 claim of its biodegradability and suitability as an eco-friendly product. The test specimens used were white to 18 transparent commercial grade plastic bags of PE origin acquired from an international franchise of household 19 goods, which were claimed to be of oxo-biodegradable nature. This study is also geared towards the 20 appropriateness of such products to reduce plastic waste accumulation in urban environments. The film samples 21 were exposed to weathering up to 20 continuous days to determine their degradability and assess their thermal 22 properties as a means to determine impact of UV induced oxo-biodegradation. Haze (%), light transmission (%) 23 and the total change in colour (ΔE) were measured as indicators to the degradation profile of the polymeric 24 materials, in addition to tensile pull mechanical properties and thermal stability. The melting peak indicates the 25 melting point (Tm) of the polymer and with exposure to weathering it showed a slight decrease from 105 to 26 102oC indicating that biodegradation mechanism was triggered. The reduction is strain at rupture was also 27 indicative of a loss in crystalline structure, coupled with Young’s modulus increase throughout weathering 28 exposure tests

Hydrophobic-modified metal-hydroxide nanoflocculants enable one-step removal of multi-contaminants for drinking water production

Flocculation is a mainstream technology for the provision of safe drinking water but is limited due to the ineffectiveness of conventional flocculants in removing trace low-molecular-weight emerging contaminants. We described a synthesis strategy for the development of high-performance nanoflocculants (hydrophobic-organic-chain-modified metal hydroxides [HOC-M]), imitating surfactant-assembling nano-micelles, by integration of long hydrophobic chains with traditional inorganic metal (Fe/Al/Ti)-based flocculants. The core-shell nanostructure was highly stable in acidic stock solution and transformed to meso-scale coagulation nuclei in real surface water. In both jar and continuous-flow tests, HOC-M was superior over conventional flocculants in removing many contaminants (turbidity, UV254, and DOC: >95%; TP and NO3-N: >90%; trace pharmaceuticals [initial concentration: 100 ng/L]: >80%), producing flocs with better structural and dewatering properties, and lowering the environmental risk of metal leaching. The rationally designed nanoflocculants have large application potential, as a solution to increasing public concern about micro-pollutants and increasing water quality requirements

Phosphatase and tensin homologue/protein kinase B pathway linked to motor neuron survival in human superoxide dismutase 1-related amyotrophic lateral sclerosis

Gene expression profiling has been used previously with spinal cord homogenates and laser capture microdissected motor neurons to determine the mechanisms involved in neurodegeneration in amyotrophic lateral sclerosis. However, while cellular and animal model work has focused on superoxide dismutase 1-related amyotrophic lateral sclerosis, the transcriptional profile of human mutant superoxide dismutase 1 motor neurons has remained undiscovered. The aim of this study was to apply gene expression profiling to laser captured motor neurons from human superoxide dismutase 1-related amyotrophic lateral sclerosis and neurologically normal control cases, in order to determine those pathways dysregulated in human superoxide dismutase 1-related neurodegeneration and to establish potential pathways suitable for therapeutic intervention. Identified targets were then validated in cultured cell models using lentiviral vectors to manipulate the expression of key genes. Microarray analysis identified 1170 differentially expressed genes in spinal cord motor neurons from superoxide dismutase 1-related amyotrophic lateral sclerosis, compared with controls. These genes encoded for proteins in multiple functional categories, including those involved in cell survival and cell death. Further analysis determined that multiple genes involved in the phosphatidylinositol-3 kinase signalling cascade were differentially expressed in motor neurons that survived the disease process. Functional experiments in cultured cells and primary motor neurons demonstrate that manipulating this pathway by reducing the expression of a single upstream target, the negative phosphatidylinositol-3 kinase regulator phosphatase and tensin homology, promotes a marked pro-survival effect. Therefore, these data indicate that proteins in the phosphatidylinositol-3 kinase pathway could represent a target for therapeutic manipulation in motor neuron degeneration

Towards safety, hygiene and environmental (SHE) management in African small and medium companies

Although Safety, Health and Environment (SHE) principles are adhered to in companies of developed countries, the application in developing countries is at its infant stage, as shown by the present article where the authors surveyed SHE Practice in 242 companies of 8 West-African countries.status: publishe

CFB cyclones at high temperature: Operational results and design assessment

Pressure drop and cut size measurements are reported for a full scale cyclone operating within a 58 MWth CFB-combustor unit at 775 degrees C. The paper reviews the vast number of equations to calculate the pressure drop and separation efficiency of cyclones, generally for operation at ambient temperature and at low C-s [< 0.5]. None of the literature correlations predicts the pressure drop with a fair accuracy within the range of experimental operating conditions. The cut size d(50) can be estimated using direct empirical methods or using the Stokes number, Stk5o. Both methods were used to compare measured and predicted values of d(50). With the exception of Muschelknautz and Krambrock, none of the equations made accurate predictions. Finally, an alternative method to determine the friction factor of the pressure drop equation (Euler number, Eu) and of the cut size is proposed. The Eu number is determined from the geometry of common cyclones, and the derived value of Stk5o defines more accurate cut sizes. The remaining discrepancy of less than 5%, when compared with the measured values, is tentatively explained in terms of a reduced cyclone diameter due to the solids layer formed near its wall. Further measurements, mostly using positron emission particle tracking, elucidate the particle motion in the cyclone and both tracking results and the influence of the particle movement on Eu and Stk(50) will be discussed in a follow-up paper. (c) 2008 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.status: publishe