Biodegradability of Epoxidized Soybean Oil Based Thermosets in Compost Soil Environment

In this study, bio-thermoset from epoxidized soybean oil (ESO) was prepared in the presence of methylhexahydrophthalic anhydride curing agent and 2-ethyl-4-methylimidazole catalyst. The crosslink densities of the synthesized ESO are ranged from 0.109 × 10^?3 to 0.308 × 10^?3 mol/cm³. The ESO bio-thermosets were exposed to the soil-burial test for 8 months. Weight change and morphology of the degraded ESO specimens were assessed. It was found that the weight loss of ESO was governed by the materials compositions, crosslink density and the soil-burial exposure time. The 3 mm thickness ESO bio-thermosets with crosslink density of 0.109 × 10^?3 mol/cm³ had fully biodegraded after soil-burial for 6 months. In addition, 16S rDNA sequencing was carried out to identify the soil microorganisms. It was suggested that Comamonas sp., Bacillus sp., Streptomyces sp. and Acinetobacter sp. are the possible soil microbes that degrade the ESO bio-thermosets in the compost soil environment.     

Biodegradation of Natural Rubber and Natural Rubber Products by <Emphasis Type="Italic">Streptomyces</Emphasis> sp. Strain CFMR 7

The rubber degrading activity of Streptomyces sp. CFMR 7 whose whole genome sequence was recently determined was tested with non-vulcanized fresh latex and common vulcanized rubber products such as latex glove, latex condom and latex car tyre. The degradation activity was unequivocally demonstrated by scanning electron microscopy with respect to microbial colonization efficiency, disintegration of rubber material and biofilm formation after 3, 6 and 9 months of inoculation. Fourier transform infrared spectroscopy comprising the attenuated total reflectance analysis on these inoculated products revealed insights into the biodegradation mechanism of this strain whereby, a decrease in the number of cis -1,4 double bonds in the polyisoprene chain, the appearance of ketone and aldehyde groups formation indicating an oxidative attack at the double bond of rubber hydrocarbon. In the presence of strain Streptomyces sp. CFMR 7, gel permeation chromatography analysis revealed a significant shift of the molecular weight distribution to lower values. Clear decrease in the molecular weight was observed over 3, 6 and 9 months of cultivation on fresh latex samples compared to other vulcanized products. No shift in the molecular weight distribution was observed for non-inoculated control. These results clearly showed that Streptomyces sp. CFMR 7 was able to cleave the carbon backbone of poly (cis -1,4-isoprene). Although this strain was able to degrade both non-vulcanized and vulcanized rubber products, faster degradation was obtained with natural rubber and rubber products with low complexity.     

Fast removal of heavy metals from water and soil samples using magnetic Fe3O4 nanoparticles

Environmental Science and Pollution Research - Heavy metal discharge from anthropogenic sources on open soil surfaces and in natural water bodies poses serious environmental and health concerns. In...     

Isolation and Characterization of a <Emphasis Type="Italic">Burkholderia</Emphasis> sp. USM (JCM15050) Capable of Producing Polyhydroxyalkanoate (PHA) from Triglycerides,Fatty Acids and Glycerols

A consortium of microorganisms from oil polluted wastewater sample was cultivated to promote polyhydroxyalkanoate (PHA) accumulation before subjecting the mixed cultures to sucrose density gradient ultracentrifugation. This resulted in the fractionation of the bacterial cells according to their physical features such as size, morphology and/or densities. An isolate was identified as Burkholderia sp. USM (JCM15050), which was capable of converting palm oil products [crude palm kernel oil (CPKO), palm olein (PO), palm kernel acid oil (PKAO), palm stearin (PS), crude palm oil (CPO), palm acid oil (PAO) and palm fatty acid distillate (PFAD)], fatty acids and various glycerol by-products into poly(3-hydroxybutyrate) [P(3HB)]. Up to 70 and 60 wt% of P(3HB) could be obtained when 0.5%(v/v) CPKO and glycerol was fed, respectively. Among the various fatty acids tested, lauric acid followed by oleic acid and myristic acid gave the best cell growth and PHA accumulation. Compared to Cupriavidus necator H16, the present isolate showed better ability to grow on and produce PHA from various glycerol by-products generated by the palm oil industry. This study demonstrated for the first time an isolate that has the potential to utilize palm oil and glycerol derivatives for the biosynthesis of PHA.     

Synthesis,characterization, and systematic studies of a novel aluminum selective chelating resin

A procedure is detailed for the selective analysis of trace aluminum by flame atomic absorption spectrophotometer coupled with off-line column separation and preconcentration. Chelating resin was synthesized by covalent functionalization of Amberlite XAD-16 by 2-(2-hydroxyphenyl) benzoxazole. The modified resin was characterized using FT-IR spectroscopy, energy dispersive x-ray analysis, elemental analysis, thermogravimetric analysis/differential thermal analysis, and minimum energy run. The optimum sorption was at pH 9?±?0.1 with corresponding t _1/2 of only 7 min. Many competitive anions and cations studied did not interfere at all in the selective determination of Al(III), at the optimized conditions. The resin shows maximum sorption capacity of 21.58 mg g^?1 and can be regenerated up to 75 cycles without any discernible capacity loss. The Langmuir isotherm model provides the better correlation of the experimental data (r ²?=?0.999) in comparison to Freundlich isotherm model, while the Scatchard analysis revealed homogeneous binding sites in the chelating resin. Analytical figures of merit were evaluated by accuracy (standard reference materials and recovery experiment), precision (RSD <5 %), and detection limit (2.8 μg L^?1). The applicability was demonstrated by analysis of trace aluminum in biological, environmental, and food samples.     

Identifying genes and gene networks involved in chromium metabolism and detoxification in Crambe abyssinica

Chromium pollution is a serious environmental problem with few cost-effective remediation strategies available. Crambe abyssinica (a member of Brassicaseae), a non-food, fast growing high biomass crop, is an ideal candidate for phytoremediation of heavy metals contaminated soils. The present study used a PCR-Select Suppression Subtraction Hybridization approach in C.?abyssinica to isolate differentially expressed genes in response to Cr exposure. A total of 72 differentially expressed subtracted cDNAs were sequenced and found to represent 43 genes. The subtracted cDNAs suggest that Cr stress significantly affects pathways related to stress/defense, ion transporters, sulfur assimilation, cell signaling, protein degradation, photosynthesis and cell metabolism. The regulation of these genes in response to Cr exposure was further confirmed by semi-quantitative RT-PCR. Characterization of these differentially expressed genes may enable the engineering of non-food, high-biomass plants, including C.?abyssinica, for phytoremediation of Cr-contaminated soils and sediments.     

Coupling between meteorological factors and ambient aerosol load

The coarser (CPM) and respirable (RPM) fractions of aerosol loads collected in a time sequence, during the onset of winter season in Delhi region, were subjected to Principal Component Analysis (15 elemental variables, 39 samples); the absolute mass contributed by each identified source to the CPM and RPM was quantified by using Absolute Principal Component Score (APCS) and Positive Matrix Factorization (PMF) method. Interestingly, the mass contributed by the local crustal source (material) to both fractions manifested undulating periodic behavior, a dominating harmonic corresponding to 24-h period was detected by using Discrete Fourier Transform (DFT). The corresponding harmonics, of varying strengths, were also detected in the recorded meteorological factors: Planetary Boundary Layer (PBL), Surface Level Temperature (T), Surface Level Relative Humidity (RH) and Wind Speed (WS). The analysis of the respective harmonic strength within the CPM, RPM, and meteorological factors suggested that the undulation observed in both size fractions of aerosol load from the local crust was affected by the meteorological factors. The large proportion of undulating loads (CPM and RPM), explained by the dominating harmonic, was fully accounted for by the empirical relation involving the discrete coupling parameters, and the recorded meteorological factors: PBL, T, RH and WS. The analysis suggests that the magnitude and the direction (‘positive’ load increase and ‘negative’ the reverse) of coupled meteorological factors'(s) effect on ambient CPM, RPM load is determined by the phase difference between the harmonic explaining the aerosol fraction's load and the corresponding harmonic present in the respective meteorological factor. The absolute mass contributions arising from the identified sources (APCS and PMF) allowed us to calculate the baseline ambient concentrations of undulating CPM and RPM loads, in the region of this study, affected by meteorological factors only.     

Cystic hygroma and congenital diaphragmatic hernia: Early prenatal sonographic evaluation of Fryns' syndrome

We report a case of cystic hygroma and diffuse lymphangiectasia detected by sonogram at 12 weeks' gestation. Fetal karyotype was normal. At 20 weeks' gestation, herniation of the bowel into the chest was noted. At delivery, the infant was diagnosed as having Fryns' syndrome. This is the first reported case of Fryns' syndrome presenting with cystic hygroma.     

Factors and sources influencing ionic composition of atmospheric condensate during winter season in lower troposphere over Delhi, India

Atmospheric condensate (AC) and rainwater samples were collected during 2010–2011 winter season from Delhi and characterized for major cations and anions. The observed order of abundance of cations and anions in AC samples was NH ₄ ⁺ ?>?Ca²⁺?>?Na⁺?>?K⁺?>?Mg²⁺ and HCO ₃ ^? ?>?SO ₄ ^2? ?>?Cl^??>?NO ₂ ^? ?>?NO ₃ ^? ?>?F^?, respectively. All samples were alkaline in nature and Σ _cation/Σ _anion ratio was found to be close to one. NH ₄ ⁺ emissions followed by Ca²⁺ and Mg²⁺ were largely responsible for neutralization of acidity caused by high NO _x and SO₂ emissions from vehicles and thermal power plants in the region. Interestingly, AC samples show low nitrate content compared with its precursor nitrite, which is commonly reversed in case of rainwater. It could be due to (1) slow light-mediated oxidation of HONO; (2) larger emission of NO₂ and temperature inversion conditions entrapping them; and (3) formation and dissociation of ammonium nitrite, which seems to be possible as both carry close correlation in our data set. Principal component analysis indicated three factors (marine mixed with biomass burning, anthropogenic and terrestrial, and carbonates) for all ionic species. Significantly higher sulfate/nitrate ratio indicates greater anthropogenic contributions in AC samples compared with rainwater. Compared with rainwater, AC samples show higher abundance of all ionic species except SO₄, NO₃, and Ca suggesting inclusion of these ions by wash out process during rain events. Ionic composition and related variations in AC and rainwater samples indicate that two represent different processes in time and space coordinates. AC represents the near-surface interaction whereas rainwater chemistry is indicative of regional patterns. AC could be a suitable way to understand atmospheric water interactions with gas and solid particle species in the lower atmosphere.     

Metal toxicity assessment of mobile phone parts using Milli Q water

Environmentally safe disposal of end-of-life (EoL) or discarded mobile phone is a serious problem on account of their ever increasing number and toxic metals contents. In the present work, metal toxicity of mobile phone plastics, printed wire boards (PWBs) and batteries were assessed through dynamic batch leaching using Milli Q (MQ) water. Phone plastics failed Toxicity Characterization Leaching Procedure (TCLP) and Waste Extraction Test (WET) for Pb as the cumulative amount of Pb leached from plastics (5.33 mg/l) exceeded the regulatory limits (5.0 mg/l) used in characterizing a waste as hazardous. Similarly, the average cumulative amount (21.83 mg/l) of Ni leached from PWBs exceeded the regulatory limit of 20 mg/l and thus PWBs failed WET. Metals leached from batteries in small amounts (Cr: 0.40 mg/l and Ni: 0.15 mg/l). The presence of Fe in the batteries and its precipitation as oxides/hydroxides in the leaching solution hindered the leaching of other metals in MQ water. Both plastics and PWBs should be treated as hazardous waste and should not be disposed in open landfills. Further, MQ water leaching could provide good simulation of metals leaching from the mobile phones disposed at landfill sites.