Cellular uptake and mutagenic potential of metal oxide nanoparticles in bacterial cells

Extensive production and consumption of nanomaterials such as ZnO and TiO₂ has increased their release and disposal into the environment. The accumulation of nanoparticles (NPs) in ecosystem is likely to pose threat to non-specific targets such as bacteria. The present study explored the effect of ZnO and TiO₂ NPs in a model bacterium, Salmonella typhimurium. The uptake of ZnO and TiO₂ bare NPs in nano range without agglomeration was observed in S. typhimurium. TEM analysis demonstrated the internalization and uniform distribution of NPs inside the cells. Flow cytometry data also demonstrates that both ZnO and TiO₂ NPs were significantly internalized in the S. typhimurium cells in a concentration dependent manner. A significant increase in uptake was observed in the S. typhimurium treated even with 8 and 80 ng mL⁻¹ of ZnO and TiO₂ NPs with S9 after 60 min, possibly the formation of micelles or protein coat facilitated entry of NPs. These NPs exhibited weak mutagenic potential in S. typhimurium strains TA98, TA1537 and Escherichia coli (WP2uvrA) of Ames test underscoring the possible carcinogenic potential similar to certain mutagenic chemicals. Our study reiterates the need for re-evaluating environmental toxicity of ZnO and TiO₂ NPs presumably considered safe in environment.     

Assessing Spatial Occurrence of Ground Level Ozone around Coal Mining Areas of Chandrapur District, Maharashtra, India

Stratospheric input and photochemical ozone formation in the troposphere are the two main sources determining the ozone levels in the surface layer of the atmosphere. Because of the importance of ozone in controlling the atmospheric chemistry and its decisive role in the heat balance of atmosphere, leading to climate change, the examination of its formation and destruction are of great interest. This study characterized the distribution of Ground level Ozone (GLO) in Chandrapur district is lying between 19°25′N to 20°45′N and 78°50′E to 80°10′E. Continuous ozone analyzer was used to quantify GLO at thirteen locations fixed by Global Positioning System (GPS) during the winter of 2005–2006. The daily GLO at all the locations ranged between 6.4 and 24.8 ppbv with an average and standard deviation of 14.9 ± 6.5 ppbv. The maximum and minimum concentration occurs during 1300–1600 h and 0300–0500 h may be due to high solar radiation facilitating photochemical production of O₃ and downward mixing from the overlying air mass and in situ destruction of ozone by deposition and/or the reaction between O₃ and NO. GIS based spatial distribution of GLO in Chandrapur district is indicates that the central core of the district and southern sites experienced elevated levels of GLO relative to the northern and western areas. The sites near by Chandrapur city are particularly affected by elevated GLO. The average variation of GLO with temperature shows a significant correlation of r = 0.55 indicating a direct relationship between GLO and temperature. Similarly an attempt has been made to compare the GLO monitored data in Chandrapur district with the reported values for other locations in Indian cities. This generated database helps regulatory agencies to identify locations where the natural resources and human health could be at risk.     

A review of the PGM industry,deposit models and exploration practices: Implications for Australia's PGM potential

Australia is prospective for platinum group metal (PGM) mineralisation (in particular primary magmatic reef, primary magmatic by-product, late magmatic and hydrothermal, and alluvial placer type) but its known PGM endowment is negligible compared to that of South Africa, Russia, the USA and Canada. Most Australian PGM projects are operated by mid-cap or junior companies and form part of larger, more diverse project portfolios held by these explorers. Most projects were ‘hot’ while market conditions were favourable. However, as other metals became ‘fashionable’ and market conditions for PGM changed, so did the focus of these companies. Pure PGM companies are rare in Australia. The search for and development of PGM-only deposits in Australia are high risk business activities. No new primary PGM deposits have been discovered since the mid to late 1980s and none of the significant deposits that were discovered or evaluated in the 1980s have been mined. This review suggests that at least several A$10 million but more likely several A$100 million were sunk into PGM exploration and development projects but none advanced to the mining stage. The viability of Australian PGM projects is very sensitive to (1) metal prices, (2) the US$/A$ exchange rate, and (3) large capital expenditure requirements relative to the small size of Australian PGM-only deposits. Most PGM-only projects were initiated at times of high PGM prices. However, advanced exploration, feasibility studies and project development always lagged behind the price booms. South Africa, Russia and Canada contain approximately 98% of the known global PGM reserves. This situation has a very negative effect on the Australian PGM industry as the well-endowed nations continue to receive the lion's share of exploration spend and new projects.     

Influence of ATD versus PMHS reference sensor inputs on computational brain response in frontal impacts to advanced combat helmet (ACH)

ABSTRACT

Objective: This study analyzed the influence of reference sensor inputs from anthropomorphic test devices (ATDs) versus postmortem human subjects (PMHSs) on simulations of frontal blunt impacts to the advanced combat helmet (ACH).

Methods: A rigid-arm pendulum was used to generate frontal impacts to ACHs mounted on ATDs and PMHS. An appropriately sized ACH was selected according to standard fitting guidelines. The National Operating Committee on Standards for Athletic Equipment (NOCSAE) head was selected for ATD tests due to shape features that enabled a realistic helmet fit. A custom procedure was used to mount a reference sensor internally near the center of gravity (CG) of the PMHS. Reference sensor data from the head CG were used as inputs for the Simulated Injury Monitor (SIMon). Brain responses were assessed with the cumulative strain damage measure set at 10%, or CSDM(10).

Results: Compared to ATD tests, PMHS tests produced 18.7% higher peak linear accelerations and 5.2% higher peak angular velocities. Average times to peak for linear accelerations were relatively similar between ATDs (5.5?ms) and PMHSs (5.8?ms). However, times to peak for angular velocities were higher by a factor of up to 3.4 for PMHSs compared to ATDs. Values for were also higher by a factor of up to 13.1 when PMHS inputs were used for SIMon.

Conclusions: The preliminary findings of this work indicate that small differences in ATD versus PMHS head kinematics could lead to large differences in strain-derived brain injury metrics such as CSDM.     

Identification and analysis of polyaromatic hydrocarbons (PAHs)—biodegrading bacterial strains from refinery soil of India

Polyaromatic hydrocarbons (PAHs) utilizing bacteria were isolated from soils of seven sites of Mathura refinery, India. Twenty-six bacterial strains with different morphotypes were isolated. These strains were acclimatized to utilize a mixture of four polycyclic aromatic hydrocarbons, i.e., anthracene, fluorene, phenanthrene, and pyrene, each at 50 mg/L concentration as sole carbon source. Out of total isolates, 15 potent isolates were subjected to 16S rDNA sequencing and identified as a member of diverse genera, i.e., Bacillus, Acinetobacter, Stenotrophomonas, Alcaligenes, Lysinibacillus, Brevibacterium, Serratia, and Streptomyces. Consortium of four promising isolates (Acinetobacter, Brevibacterium, Serratia, and Streptomyces) were also investigated for bioremediation of PAH mixture. This consortium was proved to be efficient PAH degrader resulting in 40–70 % degradation of PAH within 7 days. Results of this study indicated that these genera may play an active role in bioremediation of PAHs.     

Study on the biodegradability improvement of 2,4 dinitrophenol in wastewater using advanced oxidation/reduction process with UV/SO3/ZnO

Environmental Science and Pollution Research - 2,4-Dinitrophenol (2,4-DNP) is a toxic compound that is widely used in many industrial and agricultural processes. This compound has low...     

Dairy wastewater treatment using water treatment sludge as coagulant: a novel treatment approach

The dairy industry is among the most polluting industries as it produces large volume of wastewater that may adversely affect the environment if discharged untreated. Dairy wastewater is characterized by high COD, BOD and nutrient levels. In this study, water treatment sludge was used as a coagulant for the treatment of synthetic dairy wastewater in the pH range of 4–10. Turbidity, COD, BOD, TSS and TDS removals from the synthetic dairy wastewater were found to be around 93, 65, 67, 84 and 85%, respectively, at the optimum conditions. Water treatment sludge was found to perform even better than other conventional coagulants used for the same. Results showed that it has the potential to substitute the conventional coagulants partially or fully in the primary treatment of dairy wastewater. The utilization of water treatment sludge at dairy wastewater treatment plants would provide sustainable sludge management and cost-effective dairy wastewater treatment.     

Development of Anticorrosive Poly(Ether-Urethane) Amide Coatings from Linseed Oil: A Sustainable Resource

Polyetheramide(PEtA) resin was synthesized by the condensation polymerization of N,N-bis(2-hydroxy ethyl) linseed oil fatty amide diol (HELA) with resorcinol. It was further treated with different percentage of toluylene 2-4-diisocyanate (TDI) to obtain the urethane modified polyetheramide resins (UPEtA). The structural elucidation of PEtA and urethane modified polyetheramide(UPEtA) were carried out by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopic techniques. These analyses confirm the formation of PEtA and UPEtA. Physico-chemical and physico-mechanical analysis were performed by standard laboratory methods. The resin composition UPEtA-24 showed best physico-mechanical properties with scratch hardness 2.0 kg, impact resistance 150 lb/in. and good bending ability. The thermal stability and curing behavior of polymers were respectively studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal analysis shows that these coatings can be used safely upto 190 °C. The coatings of UPEtA resins were prepared on mild steel strips. The anticorrosive behavior of UPEtA coatings were investigated in acid, alkali, water and xylene. All the coatings exhibit good chemical resistance performance in acid, alkali, saline and organic solvents, while the resin UPEtA-24 shows the best performance.     

An updated review on advancement in fermentative production strategies for biobutanol using Clostridium spp.

A significant concern of our fuel-dependent era is the unceasing exhaustion of petroleum fuel supplies. In parallel to this, environmental issues such as the greenhouse effect, change in global climate, and increasing global temperature must be addressed on a priority basis. Biobutanol, which has fuel characteristics comparable to gasoline, has attracted global attention as a viable green fuel alternative among the many biofuel alternatives. Renewable biomass could be used for the sustainable production of biobutanol by the acetone-butanol-ethanol (ABE) pathway. Non-extinguishable resources, such as algal and lignocellulosic biomass, and starch are some of the most commonly used feedstock for fermentative production of biobutanol, and each has its particular set of advantages. Clostridium, a gram-positive endospore-forming bacterium that can produce a range of compounds, along with n-butanol is traditionally known for its biobutanol production capabilities. Clostridium fermentation produces biobased n-butanol through ABE fermentation. However, low butanol titer, a lack of suitable feedstock, and product inhibition are the primary difficulties in biobutanol synthesis. Critical issues that are essential for sustainable production of biobutanol include (i) developing high butanol titer producing strains utilizing genetic and metabolic engineering approaches, (ii) renewable biomass that could be used for biobutanol production at a larger scale, and (iii) addressing the limits of traditional batch fermentation by integrated bioprocessing technologies with effective product recovery procedures that have increased the efficiency of biobutanol synthesis. Our paper reviews the current progress in all three aspects of butanol production and presents recent data on current practices in fermentative biobutanol production technology.