Effluent composition prediction of a two-stage anaerobic digestion process: machine learning and stoichiometry techniques

Abstract

Computational self-adapting methods (Support Vector Machines, SVM) are compared with an analytical method in effluent composition prediction of a two-stage anaerobic digestion (AD) process. Experimental data for the AD of poultry manure were used. The analytical method considers the protein as the only source of ammonia production in AD after degradation. Total ammonia nitrogen (TAN), total solids (TS), chemical oxygen demand (COD), and total volatile solids (TVS) were measured in the influent and effluent of the process. The TAN concentration in the effluent was predicted, this being the most inhibiting and polluting compound in AD. Despite the limited data available, the SVM-based model outperformed the analytical method for the TAN prediction, achieving a relative average error of 15.2% against 43% for the analytical method. Moreover, SVM showed higher prediction accuracy in comparison with Artificial Neural Networks. This result reveals the future promise of SVM for prediction in non-linear and dynamic AD processes.

Graphical abstract

ᅟ

https://ift.tt/2IOT0V9

Biomonitoring levels of airborne metals around Urmia Lake using deciduous trees and evaluation of their tolerance for greenbelt development

Abstract

In the northwest of Iran, the dust of salty and toxic metals possibly caused due to drying Urmia Lake is threatening the health of surrounding communities. This study aimed to employ leaves of local deciduous trees for biomonitoring of toxic elements and to evaluate air pollution tolerance of the trees for greenbelt application. Sampling from leaves of four dominant tree species including Vitis vinifera, Juglans regia, Ulmus umbraculifera, and Popolus alba was carried out from gardens in two radial distances (5 and 10 km) around the Urmia Lake accounting for 16 sites. The concentration of metals in the leaves were extracted according to method USEPA method 3050B and measured by ICP AES technique. According to the levels of air pollution tolerance index (APTI), Popolus alba showed to be more sensitive to air pollution and can be applied for biomonitoring. The ranks of heavy metals and sodium concentrations in the leaves gained in the order of Na > Zn > Cu > Ni > Pb > As > Cd. The mean enrichment factor for the elements was calculated from 1 to 3, suggesting minor enrichment for them. As, Pb, and Na with similar spatial distribution were dominantly observed in northwest and center-east of the Urmia Lake. Potential ecological risk (PER) index showed a moderate risk in 6% of sampling zones, where Cd and As were identified as responsible pollutants. Principle component and correlation analysis between the elements depicted human sources such as industrial activity and road traffic for Cd, Cu, Ni, Pb, and Zn, whereas As and Na were most likely originated from the aerosols of Urmia Lake. Our findings showed that Popolus alba can be applied as a local biomonitor and Vitis vinifera with moderate tolerance can be used as a good air pollutant sink in greenbelt development around the drying Urmia Lake in the northwest of Iran.

https://ift.tt/2wHZCQi

Mathematics intervention for children with fetal alcohol spectrum disorder: A replication and extension of the math interactive learning experience (MILE) program

Publication date: July 2018
Source:Research in Developmental Disabilities, Volume 78
Author(s): Katrina Kully-Martens, Jacqueline Pei, Julie Kable, Claire D. Coles, Gail Andrew, Carmen Rasmussen
BackgroundIndividuals with fetal alcohol spectrum disorders (FASD) experience deficits in behavior, cognition, and academic functioning resulting from prenatal alcohol exposure (PAE). Although receiving intervention for developmental disabilities is a strong protective factor against negative outcomes in FASD, intervention research in this population is in its infancy.AimsThe purpose of this study was to replicate and extend a mathematics intervention, the Math Interactive Learning Experience (MILE) program, which was developed in the USA specifically for children with FASD.MethodsTwenty-eight Canadian children aged 4–10 years with confirmed PAE or an FASD diagnosis were assigned to either the MILE intervention or a contrast intervention.ResultsFollowing a relatively brief, individualized, one-on-one intervention, children in the MILE group demonstrated significantly greater changes in math achievement compared to the contrast group. Significant changes in other cognitive functions were not observed. Older age, lower IQ, and confirmed PAE but no FASD diagnosis were associated with greater math achievement change in the MILE group.ConclusionsThe replication and extension of the math intervention appears to have significant, positive impact on mathematics achievement scores of children with PAE and FASD.



https://ift.tt/2rLVHMP

Plasmonic colorimetric sensors based on etching and growth of noble metal nanoparticles: Strategies and applications

Publication date: 30 August 2018
Source:Biosensors and Bioelectronics, Volume 114
Author(s): Zhiyang Zhang, Han Wang, Zhaopeng Chen, Xiaoyan Wang, Jaebum Choo, Lingxin Chen
Plasmonic colorimetric sensors have emerged as a powerful tool in chemical and biological sensing applications due to the localized surface plasmon resonance (LSPR) extinction in the visible range. Among the plasmonic sensors, the most famous sensing mode is the "aggregation" plasmonic colorimetric sensor which is based on plasmon coupling due to nanoparticle aggregation. Herein, this review focuses on the newly-developing plasmonic colorimetric sensing mode – the etching or the growth of metal nanoparticles induces plasmon changes, namely, "non-aggregation" plasmonic colorimetric sensor. This type of sensors has attracted increasing interest because of their exciting properties of high sensitivity, multi-color changes, and applicability to make a test strip. Of particular interest, the test strip by immobilization of nanoparticles on the substrate can avoid the influence of nanoparticle auto-aggregation and increase the simplicity in storage and use. Although there are many excellent reviews available that describe the advance of plasmonic sensors, limited attention has been paid to the plasmonic colorimetric sensors based on etching or growth of metal nanoparticles. This review highlights recent progress on strategies and application of "non-aggregation" plasmonic colorimetric sensors. We also provide some personal insights into current challenges associated with "non-aggregation" plasmonic colorimetric sensors and propose future research directions.

Graphical abstract

https://ift.tt/2Kudj7r

Patchy gold coated Fe3O4 nanospheres with enhanced catalytic activity applied for paper-based bipolar electrode-electrochemiluminescence aptasensors

Publication date: 30 August 2018
Source:Biosensors and Bioelectronics, Volume 114
Author(s): Xin Zhang, Ning Bao, Xiliang Luo, Shou-Nian Ding
In this work, novel multifunctional patchy gold coated Fe3O4 hybrid nanoparticles (PG-Fe3O4 NPs) have been successfully synthesized in aqueous medium via a facile adsorption-reduction method. A rational formation mechanism has been proposed by monitoring the morphological evolution. The PG-Fe3O4 NPs retained the good magnetic property and exhibited excellent catalytical effeciency towards the electrochemical reduction of hydrogen peroxide. Chronoamperometric and amperometric experiments indicated a relatively high catalytic rate constant of 3.13 × 10⁵ M⁻¹ s⁻¹, a high sensitivity of 578.87 µA mM⁻¹ cm⁻² and a low Michaelis-Menten constant of 462 µM. Meanwhile, the introduction of patchy gold could help biofunctionalization via Au-S bond for different biodetection and biosensing purposes. Here, as an example, thiol-terminated aptamers were immobilized onto the patchy gold part as a signal probe to detect carcinoembryonic antigen (CEA). A related paper-based bipolar electrode-electrochemiluminescence (pBPE-ECL) aptasensor was fabricated as the low-cost, disposable and miniature platform. To improve the sensitivity, Au nanodendrites were electrodeposited at the BPE cathode as the matrix for Apt1 immobilization. This aptasensor showed a wide linear range of 0.1 pg mL⁻¹–15 ng mL⁻¹ with a low detection limit of 0.03 pg mL⁻¹, remaining competitive against other ones, and also demonstrating the PG-Fe3O4 NPs have promising potential for catalysis and bioassays.



https://ift.tt/2wI1OHw

A signal-decreased electrochemical immunosensor for the sensitive detection of LAG-3 protein based on a hollow nanobox-MOFs/AuPt alloy

Publication date: 15 August 2018
Source:Biosensors and Bioelectronics, Volume 113
Author(s): Wei Xu, Zhen Qin, Yutong Hao, Qiang He, Shuai Chen, Zhongshuang Zhang, Dan Peng, Haiyan Wen, Jun Chen, Jingfu Qiu, Chaorui Li
In this work, hollow nanobox metal-organic framework (HNM) nanocomposites were synthesised and utilised for the first time in a signal decreased electrochemical immunosensor for the ultrasensitive quantitative determination of lymphocyte activation gene-3 (LAG-3) protein, which is a newly discovered biomarker. With the aid of signal materials, namely, SiO2-tagged anti-LAG-3 antibody (SiO2-Ab2) and the biotin-streptavidin system, the sensor can achieve signal amplification. Encapsulation of tin dioxide-functionalised reduced graphene oxide (rGO-SnO2) and gold and platinum alloys (AuPt alloys) onto the surface of hollow nanobox metal-organic frameworks (MOFs) was performed to prepare rGO-SnO2/hollow nanobox-MOFs/AuPt alloys (rGO-SnO2/HNMs/AuPt) as the matrix. SiO2-Ab2, which is used as the signal-decreased label, can be utilised to enhance the distinction of the electrochemical signal after the specific recognition between antibodies and antigens, owing to its large steric hindrance property. In this sensor, this proposed sandwich immunosensor can achieve a high sensitivity, especially in the presence of low concentrations of the LAG-3 protein. Under optimal conditions, this sandwich-designed immunosensor exhibited a sensitive detection of the LAG-3 protein from concentrations of 0.01 ng mL⁻¹ to 1 μg mL⁻¹, with a lower detection limit of 1.1 pg mL⁻¹ (based on 3σ). We proposed that this ultrasensitive biosensor can be utilised for the detection of the LAG-3 protein in early clinical tumour diagnosis.

Graphical abstract

https://ift.tt/2rMEMup

Highly efficient electrochemical determination of propylthiouracil in urine samples after selective electromembrane extraction by copper nanoparticles-decorated hollow fibers

Publication date: 30 August 2018
Source:Biosensors and Bioelectronics, Volume 114
Author(s): Zeinab Tahmasebi, Saied Saeed Hosseiny Davarani, Ali Akbar Asgharinezhad
In this work, a novel, inexpensive and fast strategy was described for selective and effective extraction and determination of propylthiouracil (PTU) with a high polarity (log P = 1.2) based on electromembrane extraction (EME) followed by differential pulse voltammetry (DPV). For this purpose, copper nanoparticles (CuNPs)-decorated hollow fiber was used as the selective membrane for EME of PTU in urine samples. The influential parameters on extraction such as extraction solvent, pH, agitation speed, applied potential and extraction time were systematically investigated. In optimized conditions, acceptable linearity was attained between 0.05 and 5 µg mL⁻¹ (R² value = 0.9994); moreover, superb enrichment factor (200) and repeatability (RSD%, n = 4, 5.7%) for 0.1 µg mL⁻¹ of PTU solution were in desirable range. In addition, extraction recovery of 80.0% was achieved in this condition and the limit of detection (S/N ratio of 3:1) was 0.02 µg mL⁻¹. Finally, the proposed method was successfully applied to determine PTU concentration in urine samples.

Graphical abstract

https://ift.tt/2wJCUr7