Removal of Arsenic (III) from groundwater applying a reusable Mg-Fe-Cl layered double hydroxide

BACKGROUND: Layered double hydroxide compounds (LDHs) have been applied for the removal of oxyanions including arsenate (As(V)). However, the aim of this present research is to develop a LDH to treat arsenite (As(III)). Both batch and column sorption studies were conducted to assess the effect of LDH dosage, contact time, solution pH and initial As(III) concentrations on the As(III) removal performance. The potential re-use of this sorbent was also investigated.<p></p> RESULTS: For 2 g L−1 of Mg-Fe-Cl LDH, As(III) in test solution can be reduced from 400 µg L−1 to <10 µg L−1 after a contact time of 2 h. High As(III) concentration in Bangladesh groundwater can be reduced to meet the national drinking water standards (<50 µg L−1). The maximum adsorption capacity of As(III) by Mg-Fe-Cl LDH is 14.6 mg g−1-LDH. Further, reusability of this sorbent was at least 20 cycles of regeneration with effective As(III) removal between 93.0 and 98.5%. Moreover, As(III) removal was unaffected by the solution pH but affected by the co-existing competing anions and concentration of As(III). Finally, the main mechanism of As(III) removal by Mg-Fe-Cl LDH was suggested to be chemical sorption together with anion and ligand exchange with interlayer Cl− and OH− ions.<p></p> CONCLUSION: High efficiency of sorption of As(III) by the developed Mg-Fe-Cl LDH was demonstrated in this study which is generally not the case for most other sorbent materials. Pilot-scale trials are needed to explore the suitability of full application of the developed Mg-Fe-Cl LDH for the removal of As(III).<p></p&gt

The role of cytokinins in clubroot disease

Clubroot (Plasmodiophora brassicae) is a pathogen of Brassicaceae that causes significant reductions in yield as a consequence of gall formation in the root and hypocotyl of infected plants. The pathogen hijacks host vascular cambium development, and cytokinins are implicated in this process. This paper uses transcriptomics and metabolomics to investigate changes in cytokinin metabolism during gall formation of clubroot-infected Arabidopsis thaliana. RNASeq analysis of infected tissue showed that host cytokinin metabolism was strongly down-regulated both at the onset and late stages of gall formation. Expression of host genes associated with cytokinin biosynthesis, signalling, degradation and conjugation was strongly repressed. Analysis of cytokinin precursors, active components and conjugates by microanalytical techniques was consistent with these transcriptional responses. Two isopentenyltransferase genes associated with cytokinin biosynthesis are present in the P. brassicae genome and are expressed throughout gall formation. The impact of pathogen-derived cytokinins on the total cytokinin content of infected tissue and host gene expression was minimal in wild type plants. However, infection of ipt1;3;5;7 mutants that are severely restricted in their ability to synthesise active cytokinins led to an increase in expression of host cytokinin-responsive genes. We interpret these results as indicating that P. brassicae can synthesise small amounts of cytokinin, but this has little impact on the host plant as the ipt1;3;5;7 phenotype is not rescued. Intriguingly, plasmodial development was slowed and spore viability reduced in these mutants indicating a potential role for cytokinins in plasmodial development

Evaluation of Electrostatic Particle Ionization and Biocurtain™ Technologies to Reduce Air Pollutants from Broiler Houses

The continuing growth of poultry production, along with the increasing urbanization of rural areas, is leading to more odor-related complaints from neighboring communities and more scrutiny from policy makers. It is, therefore, in the best interest of poultry producers to look at control methods for abating odors. Previous studies have shown that substantial amounts of volatile and odorous compounds are adsorbed and transported by dust particles. Thus, by reducing the amount of dust emitted from poultry facilities such as broiler houses, odor may be reduced as well. The objective of this study was to evaluate the effectiveness of two commercially available control technologies (BioCurtain™ and electrostatic particle ionization (EPI) system) in reducing the total suspended particulate matter (TSP), particulate matter \u3c10 \u3eμm in diameter (PM10), ammonia (NH3), and hydrogen sulfide (H2S) emitted from a broiler facility in Texas. The study was conducted at a broiler production facility in two identically designed, ventilated, and managed broiler houses where one served as the treatment house and the other, the control. Measurements were done on two consecutive days each in September and December 2010. BioCurtain™ was tested independently on the first day and in combination with and the EPI on the second day. Reductions in the NH3 and H2S emission rates by as much as 8% (1040 vs. 943 g/h for NH3 and 9.2 vs. 8.4 g/h for H2S) and by as much as 43% (396 vs. 227 g/h) for the TSP emission rates were achieved with the BioCurtain ™. The EPI system reduced the NH3, H2S, and TSP emission rates by as much as 17%, 34% and 39%, respectively. Economic analysis showed that operating the automated EPI and BioCurtain™ system for one 14 m wide and 152 m long broiler building housing an average of 23,000 birds will cost $0.06 per bird

Cost Analysis of Pico hydro Turbine for Power Production

Background: Turbine played a significant role in the hydro system and a determinant of the quality and quantity production of electric power in each power system. Objective: In this paper, several types of pico hydro water turbines are reviewed and compared. The water head, water flow rate and the current market price are the basic aspects considered in discussing the turbines selection. Results: Most of the small hydro turbines currently available are mostly suitable for low head high flow or high head low flow condition. By the assumption that the percentage of turbine efficiency is consistent for all conditions of water resources, the ability of water turbine to produce high output during low head low flow condition is low. Conclusion: The effectiveness of a turbine does not only depends on the productivity of the turbine to generate output power, but must also be seen in terms of cost and economical investment

Effect of local medicinal herbs as feed additives on production performance and faecal parameters in laying hens

Medicinal herbs are gaining importance in both human and animal nutrition due to their bioactive components that possess a wide range of beneficial effects on body health enhancement. To concord with the banning of antibiotic growth promoters in animal nutrition, research was carried out to utilize phytogenic feed additives in poultry nutrition as the alternative to improve their overall performance. Therefore, the objective of this study was to evaluate the effects of dietary supplementation of the three selected herbs at the level of 1% on production performance and faecal parameters in laying hens. In this study, a total of 96 Bovans Brown layers of 32 wk old were subjected to four dietary treatments in the form of CRD, namely (T1) control, (T2) basal diet + 1% of turmeric rhizome powder, (T3) basal diet + 1% of Vietnamese coriander leaf powder, and (T4) basal diet + 1% of Dayak onion powder. The layers were given 7-d adaption period before the feeding trial started which lasted for 12 wk. The results showed that there was no significant difference (P>0.05) in the means of overall feed intake, egg mass, feed conversion efficiency as well as body weight gain among the treatment groups. The hen-day egg production and egg weight of birds in treatments T2 and T4 showed significant differences (P<0.05) compared to control group. Besides, the birds in the treatment groups supplemented with medicinal herbs (T2, T3 and T4) also showed significant reduction in faecal pH and faecal Entero bacteriaceae counts (P<0.05) compared to the control, while significantly improved (p<0.05) the faecal lactic acid bacteria counts as compared to those in the control group. Thus, the present study suggests that dietary supplementation of 1% of turmeric rhizome powder, Vietnamese coriander leaf powder and Dayak onion powder in layer diet can achieve better performance in terms of hen-day egg production and egg weight associated with favourable intestinal environment without any adverse effect

Effects of silicon dioxide as the polar dielectric on the infrared absorption spectrum ofthemetal-insulator-metal metasurface

Metal-insulator-metal metasurfaces have been widely used as high-performance absorbers in almost all electromagnetic spectral ranges. Their absorption spectra can be engineered by making variations in the geometry of the unit cells and/or by embedding materials with specific optical constants. Including a polar dielectric in their structure is another approach for manipulating their absorption spectra. In this research, we have numerically and experimentally investigated the effect of using silicon dioxide (SiO2) as a polar dielectric on the absorption spectrum of a metal-insulator-metal metasurface composed of a tri-layer of Ni-SiO2-Ni. Our results have shown the presence of absorption peaks in the mid-infrared which are attributed to the excitation of the optical phonons in the SiO2 spacer layer. Particularly, the excitation of the Berreman mode in the SiO2 spacer layer was observed and its effect on the total absorption spectrum is studied. The parametric effects of the top patterned Ni layer, the incident angle, and the polarization are also investigated. This study can provide engineering capabilities for the mid-infrared absorbers and reflection filters

Toward An Understanding Of The Retinal Chromophore In Rhodopsin Mimics

Recently, a rhodopsin protein mimic was constructed by combining mutants of the cellular retinoic acid binding protein II (CRABPII) with an all-trans retinal chromophore. Here, we present a combine computational quantum mechanics/molecular mechanics (QM/MM) and experimental ultrafast kinetic study of CRABPII. We employ the QM/MM models to study the absorption (lambda(a)(max)), fluorescence (lambda(f)(max)), and reactivity of a CRABPII triple mutant incorporating the all-trans protonated chromophore (PSB-KLE-CRABPII). We also study the spectroscopy of the same mutant incorporating the unprotonated chromophore and of another double mutant incorporating the neutral unbound retinal molecule held inside the pocket. Finally, for PSB-KLE-CRABPII, stationary fluorescence spectroscopy and ultrafast transient absorption spectroscopy resolved two different evolving excited state populations which were computationally assigned to distinct locally excited and charge-transfer species. This last species is shown to evolve along reaction paths describing a facile isomerization of the biologically relevant 11-cis and 13-cis double bonds. This work represents a first exploratory attempt to model and study these artificial protein systems. It also indicates directions for improving the QM/MM models so that they could be more effectively used to assist the bottom-up design of genetically encodable probes and actuators employing the retinal chromophore

Natural history of Arabidopsis thaliana and oomycete symbioses

Molecular ecology of plant–microbe interactions has immediate significance for filling a gap in knowledge between the laboratory discipline of molecular biology and the largely theoretical discipline of evolutionary ecology. Somewhere in between lies conservation biology, aimed at protection of habitats and the diversity of species housed within them. A seemingly insignificant wildflower called Arabidopsis thaliana has an important contribution to make in this endeavour. It has already transformed botanical research with deepening understanding of molecular processes within the species and across the Plant Kingdom; and has begun to revolutionize plant breeding by providing an invaluable catalogue of gene sequences that can be used to design the most precise molecular markers attainable for marker-assisted selection of valued traits. This review describes how A. thaliana and two of its natural biotrophic parasites could be seminal as a model for exploring the biogeography and molecular ecology of plant–microbe interactions, and specifically, for testing hypotheses proposed from the geographic mosaic theory of co-evolution