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 Biomedical Imaging and Intervention JournalNumber of Followers: 5     Open Access journal ISSN (Print) 1823-5530 Published by U of Malaya  [2 journals]
• Erratum to: The impact of telecommuting on personal vehicle usage and
environmental sustainability

• PubDate: 2015-06-01

• A critical assessment of the use of a surface reaction rate equation to
correlate biosorption kinetics

• Abstract: Abstract A critical assessment of the use of a variable-order, power-law type surface reaction rate equation to correlate biosorption kinetics is presented. The general nth order rate equation with three adjustable parameters was fit to the kinetic data of lead uptake by inactivated cells of Rhodotorula glutinis using a genetic algorithm search method. The uptake process was fast, with apparent equilibrium reached in approximately 30 min. According to the Akaike information criterion test, the three-parameter nth order equation was superior to the much used pseudo second order equation with two fitting parameters. However, the strong fit of the former equation resulted in unrealistic parameter estimates. Parametric sensitivity analysis indicated that the available kinetic data with only limited information content did not allow simultaneous identification of three unknown parameters. As a result, the three-parameter nth order equation was found to be overparameterized with highly correlated parameters. It was, however, possible to retrieve meaningful parameter estimates from the kinetic data when the number of fitting parameters was reduced from 3 to 2.
PubDate: 2015-06-01

• Highly efficient adsorption of hexavalent chromium from the aqueous system
using nanoporous carbon modified with tetraethylenepentamine

• Abstract: Abstract An oxidized mesoporous carbon material, modified with tetraethylenepentamine, has been developed as a highly efficient adsorbent for hexavalent chromium. Influence of parameters such as adsorbent dose (0.1–0.8 g L−1) solution pH (1–9), contact time, and initial concentration (100–1,000 mg L−1) on adsorption capacity has been investigated and optimized. The sorption equilibrium was reached within 60 min. The structural order and textural properties of the synthesized material were studied by X-ray diffraction, scanning electron microscopy, Fourier transform infrared, and nitrogen adsorption–desorption analysis. The experimental results were analyzed by the Langmuir and Freundlich isotherms. The maximum adsorption capacity of 510 mg g−1 at an initial concentration of 1,000 mg L−1 is well predicted by the Freundlich isotherm. The kinetic analysis indicated that the adsorption process was successfully fitted with the pseudo-first-order kinetic model. Compared to other adsorbents reported in the literature, the modified nanoporous carbon material prepared in this study is found to be highly efficient adsorbent for the removal of hexavalent chromium from wastewater.
PubDate: 2015-06-01

• Ferrous oxalate, maghemite and hematite nanorods as efficient adsorbents
for decontamination of Congo red dye from aqueous system

• Abstract: Abstract In this present study, we have synthesized ferrous oxalate nanorods by a modified co-precipitation methods. The obtained nanomaterial (ferrous oxalate nanorod) was calcined at higher temperatures to form both maghemite and hematite nanorods. The morphology, size, crystalline phases, formation and surface area of the nanorods were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, Fourier transform infrared spectroscope, ultraviolet–visible diffuse reflectance spectroscope and Brunauer–Emmett–Teller surface area analytical techniques. The results showed that high-yield aligned nanorods with a typical diameter of 100–200 nm and length up to micrometers were formed. The obtained rod-shaped nanomaterials (i.e., ferrous oxalate, maghemite and hematite) were used as adsorbents and were applied to remove Congo red (CR) dye molecules, which was used as a model of organic pollutants in aqueous solution. The adsorption isotherms and kinetics of removal of CR were studied. It was found that the adsorption capacity of maghemite nanorod is highest among the three adsorbents and can be regarded as an effective adsorbent for removal of CR from aqueous solution.
PubDate: 2015-06-01

• Analysis of aerodynamic sound noise generated by a large-scaled wind
turbine and its physiological evaluation

• Abstract: Abstract Aerodynamic noise generated from a modern large-scale wind turbine was measured and analyzed from an engineering point of view. The measurement items were the sound, the sound pressure level (including the infrasound with extremely low-frequency band) and the corresponding physiological evaluation. Fifteen test subjects received various sound stimuli, including the recorded aerodynamic noise and a synthetic periodical sound, were examined with an electroencephalogram as a physiological evaluation. It was observed from the mapping patterns of brain waves that alpha 1 rhythm, which indicates a relaxed and concentrated state, after the sound stimulus with the frequency band of 20 Hz, showed the lowest value among the other cases. That is, the test subjects cannot keep relaxed and their concentration after hearing the sound stimulus at the frequency band of 20 Hz. The induced rate of alpha 1 rhythm almost decreased when the test subjects listened to all the sound stimuli, and further decreased with decreased frequency. Meanwhile, beta 1 rhythm, which shows a strain state, after the sound stimulus with the frequency band of 20 Hz, showed the highest value among the other cases. Therefore, the infrasound (e.g., low frequency and inaudible for human hearing) was considered to be an annoyance to the technicians who work in close proximity to a modern large-scale wind turbine.
PubDate: 2015-06-01

• Distribution of organochlorine pesticides in atmospheric air of Tamilnadu,
southern India

• Abstract: Abstract Passive air sampling was performed for urban, suburban, coastal, and agriculture air during April 2009–January 2010 in Tamilnadu, southern India, to know the distribution and fate of organochlorine pesticides (OCPs) residues. Exposed polyurethane foam samples (30 ± 2 days) were soxhlet extracted, and the extracts were analyzed using gas chromatography–mass spectrometric method. The total concentrations of 13 OCPs were in the range of not detected (ND)–41,400 pg/m3. Dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethylene, heptachlor, and mirex were found predominant during monsoon season. The elevated α/γ isomer ratio of hexachlorocyclohexane (HCH) (5.03) during summer revealed fresh/recent usage of HCH in coastal area. Dichlorodiphenyltrichloroethane ratio shows its fresh application in all the locations during monsoon season, which probably used to contain the diseases causing vectors. Detection of banned pesticides, such as aldrin, dieldrin, and heptachlor in air, indicating their illegal usage/or from old source. Furthermore, mirex, an unregistered pesticide in India, is being reported for the first time in air. More importantly, the obtained information will be used as a valuable baseline data for the management of atmospheric OCPs in future.
PubDate: 2015-06-01

• Bacterial community change through drinking water treatment processes

• Abstract: Abstract The microbiological quality of drinking water has aroused increasing attention due to potential public health risks. Knowledge of the bacterial ecology in the effluents of drinking water treatment units will be of practical importance. However, the bacterial community in the effluents of drinking water filters remains poorly understood. The changes of the density of viable heterotrophic bacteria and bacterial populations through a pilot-scale drinking water treatment process were investigated using heterotrophic plate counts and clone library analysis, respectively. The pilot-scale treatment process was composed of preozonation, rapid mixing, flocculation, sedimentation, sand filtration postozonation, and biological activated carbon (BAC) filtration. The results indicated that heterotrophic plate counts decreased dramatically through the drinking water treatment processes. Clone library analysis indicated the significant change of bacterial community structure through the water treatment processes. Betaproteobacteria was dominant in raw water, the sand filter effluent and the BAC filter effluent. This work could provide some new insights on drinking water microbial ecology.
PubDate: 2015-06-01

• Mitigation of water repellency in the treatment of contaminated muds using
the chemical–biological stabilization process

• Abstract: Abstract The soil–water relationship was used to evaluate the efficacy of a novel remediation technology, the chemical–biological stabilization process, which focuses principally on soil fertility restoration in agricultural sites. This process was evaluated for the treatment of 150 m3 of bentonitic drilling muds from a closed sulfur mine which contained 70 % fines (<0.05 mm), and which had been contaminated with very weathered hydrocarbons, containing 31 % asphaltenes. This material was monitored for two and a half years, for in situ moisture content, field capacity, and soil water repellency. Additionally, critical soil moisture content for water drop penetration times of <5 and <60 s was monitored. Field capacity increased 46.6 % with respect to initial values and a vigorous vegetative growth was established. Concurrently, water repellency values for molarity ethanol droplet and water drop penetration times were reduced from 5.1 to 3.9 M and 106 to 0.12 h, respectively. Soil in situ moisture content during the driest part of the year (20.3 % humidity) remained above critical values (15.1 % humidity and 19.5 % humidity) to avoid a water repellency of <5 and <60 s, respectively, and water repellency was not observed in the field. Thus, complete mitigation of water repellency was achieved. These findings indicate that the soil–water relationship should be evaluated to achieve an integral soil remediation and that water repellency as a remediation criterion should be complemented with determinations of critical moisture content and actual site information on soil in situ moisture content during the annual cycle.
PubDate: 2015-06-01

• Biosorption of nickel and cobalt from plant effluent by Sargassum
glaucescens nanoparticles at new membrane reactor

• Abstract: Abstract In this study, brown algae (Sargassum glaucescens) nanoparticles were prepared by using a planetary ball mill to remove nickel and cobalt. The biosorption reaction in the reactor was studied under different conditions of pH, biosorbent dose, temperature, and retention time. The concentration of heavy metals was investigated after the fluid had passed through the membrane system. Algae nano-biosorbent was prepared using a planetary ball mill; scanning electron microscope and Brunauer–Emmert–Teller tests showed an average diameter of 95.75 nm and specific surface area of 11.25 m2/g, respectively. A maximum biosorption efficiency equal to 93 and 91 % was achieved for nickel and cobalt at pH 6, temperature 35 °C with a retention time of 80 min, and at biosorbent doses of 8 and 4 g/l. The kinetic data fit well by pseudo-first-order model, and equilibrium data of metal ions could be described well with the Langmuir and Dubinin–Radushkevich isotherm models. The calculated thermodynamic parameters showed that metal ion biosorption is feasible, endothermic, and naturally spontaneous.
PubDate: 2015-06-01

• Minimization of phosphorus in the fermentation media of Escherichia coli
producing a model recombinant protein

• Abstract: Abstract In the biotechnology sector, a main processing goal is the production of high cell (and hence product) yields. Therefore, little consideration is traditionally given to the potential environmental impacts of excess culture media ingredients. This study investigated the scope for reducing the quantities of phosphorus (P) present in both a complex terrific broth (TB) and semi-defined minimal media 9/yeast extract (M9/YE) fermentation media used to culture a model Escherichia coli strain engineered to produce a recombinant β-galactosidase. Reductions of up to 70 % did not adversely affect biomass yields attained; however, further P minimization leads to a drop in dry cell weight obtained, particularly in the case of semi-defined media. P concentration in TB media had little effect upon total recombinant protein expression levels achieved. In the case of M9/YE media, reductions >70 % P negatively affected product expression levels. Protein functionality, assessed by k m and V max, was not influenced by the type of media nor the P concentration present. Overall, the results indicate that P can be reduced by a minimum of 70 % without adversely affecting the biomass yield, the recombinant protein yield or functionality. Such reductions should lead to significant P savings in the large-scale manufacturing of proteins produced by genetic engineering in E. coli.
PubDate: 2015-06-01

• Removal of zinc and lead ions by polymer-enhanced ultrafiltration using
unmodified starch as novel binding polymer

• Abstract: Abstract The removal of zinc and lead from aqueous dilute solutions by polymer-enhanced ultrafiltration process using unmodified starch as a new binding polymer was studied. Experiments were performed to determine the effects of transmembrane pressure, pH, concentration of metal ions on the retention and permeate flux. The performance of the proposed new binding polymer was compared to that of polyethyleneimine a conventional polymer frequently used in polymer-enhanced ultrafiltration. The retention of zinc and lead ions reached 96 and 66 %, respectively, using 0.05 % unmodified starch at pH 7. Overall unmodified starch showed better retention for zinc ions then polyethyleneimine, whereas polyethyleneimine retention for lead ions was higher. Solution pH was found to have little effect on flux.
PubDate: 2015-06-01

• Mitigation of arsenic in rice through deficit irrigation in field and use
of filtered water in kitchen

• Abstract: Abstract An experiment was conducted in an arsenic-affected area of West Bengal, India, with the aim of alleviating arsenic toxicity from food chain through water management in rice field and modification of cooking procedure of the same grain in kitchen. Three regimes of deficit irrigation, viz. intermittent ponding, saturation and aerobic condition were tested in field against continuous ponding, i.e. local farmers’ practice. Produced grains were cooked in traditional method with both arsenic-contaminated and filtered water. Results revealed that deficit irrigation can be efficiently used to reduce the arsenic load in rice grain. Water management in field can reduce 9–21 % arsenic content in raw rice grain and can save 150–340 mm of irrigation water over traditional cultivation procedure. Furthermore, use of filtered water for cooking can alleviate up to 32 % of arsenic. The study also revealed that growing rice under deficit irrigation can also increase the water use efficiency of the crop.
PubDate: 2015-06-01

• Evolution of chemical and biological characterization during thermophilic
composting of vegetable waste using rotary drum composter

• Abstract: Abstract Vegetable waste usually contains high levels of organic matter, moisture and nutrients that make the waste unsuitable for disposal in municipal landfills. Composting of vegetable waste is in practice by many urban local bodies, and therefore, it was composted along with cow dung and sawdust in a 550-L batch scale rotary drum composter. Four different trials of varying waste combinations of vegetable waste, cow dung and sawdust, i.e., trial 1 (5:4:1), trial 2 (6:2:1), trial 3 (7:2:1) and trial 4 (8:1:1) were composted by adding 10 kg of dry leaves as bulking agent with a total mass of 100 kg. With proper combinations of organic waste mix, a maximum temperature of 66.5 °C was observed in trial 1 and 61.4 °C in trial 2, when compared to other two trials with prolonged thermophilic period. Due to such elevated temperature, higher degradation was observed in trials 1 and 2 with inactivation of pathogens to considerable amounts. Furthermore, final compost had total nitrogen of 2.31 and 3.01 %, total phosphorous of 4.30 and 3.27 % and final carbon-to-nitrogen ratio of 15 and 12, in trials 1 and 2, respectively. Carbon dioxide evolution and oxygen uptake rate of compost samples was analyzed for its stability and was observed to reduce completely at the end of 20 days with lower emission rates.
PubDate: 2015-06-01

• Synthesis and characterization of silica microsphere and their application
in removal of uranium and thorium from water

• Abstract: Abstract Uranium (U) and thorium (Th) are known to cause acute toxicological effects in human, and their compounds are potential occupational carcinogens. During this work, silica microspheres were used to decontaminate the traces of U and Th in different water sources originated from groundwater and lake water. Ultra-filtration technique was used to isolate the microsphere from the water samples. Silica microspheres were synthesized based on a polyvinylpyrrolidone involved emulsion polymerization and subsequent sol–gel process. The microspheres were characterized for their size by using dynamic light scattering, and presence of silicate structure is verified by recording their attenuated total reflectance-Fourier transform infrared spectrum. The surface morphologies of the prepared silica microspheres were studied by using scanning electron microscope. Water samples collected from the groundwater and lake water were spiked with U and Th in the concentration range of 100–1,000 ng mL−1. The results of batch sorption experiments suggest that silica microsphere is very effective at pH 3, and sorption is more than 99.9 %. Equilibrium sorption follows Langmuir isotherms and the maximum U, and Th uptake is 30 and 36 mg g−1, respectively. Major physicochemical characteristics of the water were monitored before and after the decontamination process. Experimental results show no significant variations in any of the measured parameters.
PubDate: 2015-06-01

• Using oyster tissue toxicity as an indicator of disturbed environments

• Abstract: Abstract Crassostrea virginica (the Eastern or American oyster) bioaccumulates pollutants from the water column, and therefore, its tissues can be used as bioindicators of past and present estuarine health. In this pilot project, we decided to investigate whether its tissues would be a suitable medium for toxicity testing using tissues from a variety of southern Texas locations of known and suspected anthropogenically impacted and unimpacted areas. We also conducted toxicity tests on sediments adjacent to oyster reefs using standard protocols for sediment toxicity. We tested the toxicity of tissues and sediments on the luminescent bacteria Vibrio fischeri, whose bioassays are commonly referred to by the trade name Microtox®. Microtox tests are quick, relatively inexpensive and sensitive to a range of contaminants. Evidence from this preliminary study suggests that conducting toxicity tests on oyster tissues may predict localized contamination better than when conducting toxicity tests on subtidal sediment. The refinement of these methods to use oyster tissues to detect contamination may be especially useful for environmental impact studies and/or studies where rapid and inexpensive information is needed.
PubDate: 2015-06-01

• Effect of hydraulic retention time on performance of an anoxic–aerobic
sequencing batch reactor treating saline wastewater

• Abstract: Abstract The effects of hydraulic retention time on the performance and microbial community structure of an anoxic–aerobic sequencing batch reactor treating saline wastewater were investigated. The average removal efficiencies of chemical oxygen demand and ammonia nitrogen decreased from 90 and 85 % to 68 and 71 % with the decrease in hydraulic retention time from 17 to 9 h, respectively. No obvious accumulation of nitrate nitrogen and nitrite nitrogen in the effluent was found. The contents of polysaccharide and protein in extracellular polymeric substances increased with the decrease in hydraulic retention time. The polysaccharide/protein ratio decreased from 1.18 to 1.11 with the decrease in hydraulic retention time from 17 to 9 h. The increase in extracellular polymeric substances with the decrease in hydraulic retention time led to the increase in sludge volume index. The specific ammonium oxidation rate, specific nitrite oxidation rate, specific nitrate reduction rate, and specific oxygen uptake rate increased with the decrease in hydraulic retention time. The diversity indices of microbial community decreased from 2.69 to 2.39 with the decrease in hydraulic retention time from 17 to 9 h. The α-proteobacteria were the dominant groups under hydraulic retention time of 17, 14, 11, and 9 h, which constituted 46, 30, 40, and 40 % of the whole microbial community, respectively.
PubDate: 2015-06-01

• Efficient adsorption of dibutyl phthalate from aqueous solution by
activated carbon developed from phoenix leaves

• Abstract: Abstract The adsorption of dibutyl phthalate (DBP) from aqueous solution using phoenix leaves activated carbon (PLAC) by chemical activation with phosphate was investigated. After scanning electron microscopy, energy dispersive X-ray spectrometry, Brunauer–Emmett–Teller (BET) and infrared spectrum characterization of PLAC, the influences of solution pH, contact time, initial DBP concentration and temperature on the adsorption rate were investigated. The isotherm, kinetic and thermodynamic parameters were explored to describe the experimental data. The PLAC has a heterogeneous distribution of grain and a well-developed porous structure. The main elements of PLAC are 24.26 % carbon, 70.65 % oxygen and 3.75 % phosphor. The BET surface area of the sample is 593.52 m2/g with the average pore diameter of 6.31 nm. The single-point total pore volume was found to be 0.52 cm3/g. The infrared spectrum showed the complexity of the material. The maximum DBP adsorption rate was 97.36 %, and the maximum adsorption capacity was 48.68 mg/g at pH 13. The monolayer sorption capacity of the biosorbent for DBP was found as 133.33 mg/g with the Langmuir isotherm. The equilibrium data fitted with Freundlich isotherm better than Langmuir, Dubinin–Radushkevich and Temkin isotherm. The kinetic data were best described by the pseudo-second-order model better than pseudo-first-order kinetic, intraparticle diffusion, and Elovich model. The thermodynamic studies indicated that the sorption process spontaneous, thermodynamically favorable and endothermic. The PLAC can be an alternative material for treatment of DBP wastewater.
PubDate: 2015-06-01

• A novel method for synthesis of nano-γ-Al 2 O 3 : study of adsorption

• Abstract: Abstract Nano-γ-Al2O3 adsorbent was synthesized by the novel sol–gel method. The adsorbent was characterized by transmission electron microscope, Fourier transform infrared and X-ray powder diffraction. The effects of several variables such as, adsorbent weight, pH and contact time on adsorption of chromium (Cr6+), nickel (Ni2+), cadmium (Cd2+) and lead (Pb2+) ions were studied in batch experiments. The results showed that the synthesized nano-γ-Al2O3 had a good capacity to adsorb Cr and Pb. The kinetic data were described with pseudo-first- and pseudo-second-order models. Three isotherm models, namely Freundlich, Langmuir and Tempkin, were used for analysis of equilibrium data, and results showed that Langmuir and Freundlich models were suitable for describing the equilibrium data of Cr6+, Cd2+, Ni2+ and Pb2+. Using Langmuir isotherm, the maximum sorption capacities of Cr6+, Pb2+, Cd2+ and Ni2+ were estimated to be 13.3, 6, 1.1 and 0.33 (mg/g) at 25 °C, respectively. The sorption capacity did not change remarkably after reuse of sorbent for sorption–desorption cycle. The selectivity order of Cr6+, Pb2+, Cd2+ and Ni2+ sorption onto the adsorbent was Cr6+ > Pb2+ > Cd2+ > Ni2+.
PubDate: 2015-06-01

• Hydrocarbon pollution does not influence bacterial diversity as much as
geographic location: a Korean case study

• Abstract: Abstract Bacterial diversity of hydrocarbon-contaminated sites in various regions of Korea was investigated to ascertain the influence of hydrocarbon pollution on bacterial diversity using terminal restriction fragment length polymorphism (T-RFLP) and differential gel gradient electrophoresis. Thirty-two hydrocarbon-contaminated soil samples were collected from seven different geographical locations in Korea. A dendrogram of T-RFLP profiles for the bacterial community structure in soil samples using Ward’s method with Jaccard distance showed that samples from the same location clustered together. Principal components analysis (PCA) and self-organizing maps (SOM) of terminal restriction fragments were also used to characterize the associations among samples. PCA and SOM results also showed that soil bacterial communities were classified according to locations, but not by hydrocarbon pollution level. Moreover, correlation analyses prove a direct correlation between bacterial diversity and meteorological parameters, whereas no significant correlation was observed with hydrocarbon contamination levels. These results suggest that geographical origin, rather than soil contamination level, might be more important in determining the bacterial diversity of crude oil-contaminated soils. Environmental factors, which play a major role in determining natural bacterial diversity which in turn should be enriched for effective bioremediation, should be the central dogma while considering bioremediation of hydrocarbon-contaminated sites.
PubDate: 2015-06-01

• Mid-infrared spectroscopy and partial least-squares regression to estimate
soil arsenic at a highly variable arsenic-contaminated site

• Abstract: Abstract The potential of mid-infrared spectroscopy in combination with partial least-squares regression was investigated to estimate total and phosphate-extractable arsenic contents in soil samples collected from a highly variable arsenic-contaminated disused cattle-dip site. Principal component analysis was performed prior to mid-infrared partial least-squares analysis to identify spectral outliers in the absorbance spectra of soil samples. The mid-infrared partial least-squares calibration model (n = 149) excluding spectral outliers showed an acceptable reliability (coefficient of determination, $$R_{\text{c}}^{2}$$  = 0.75 (P < 0.01); ratio of performance to interquartile distance, RPIQc = 2.20) to estimate total soil arsenic. For total soil arsenic, the validation of final calibration model using 149 unknown samples also resulted in a good acceptability with $$R_{\text{v}}^{2}$$  = 0.67 (P < 0.05) and RPIQv = 2.01. However, the mid-infrared partial least-squares calibration model based on phosphate-extractable arsenic was not acceptable to estimate the extractable (bioavailable) arsenic content in soil ( $$R_{\text{c}}^{2}$$  = 0.13 (P > 0.05); RPIQc = 1.37; n = 149). The results show that the mid-infrared partial least-squares prediction model based on total arsenic can provide a rapid estimate of soil arsenic content by taking into account the integrated effects of adsorbed arsenic, arsenic-bearing minerals and arsenic associated with organic components in the soils. This approach can be useful to estimate total soil arsenic in situations, where analysis of a large number of samples is required for a single soil type and/or to monitor changes in soil arsenic content following (phyto)remediation at a particular site.
PubDate: 2015-06-01

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