Accumulation Potential Research Articles

High-resolution spatial and genomic characterization of coral-associated microbial aggregates in the coral Stylophora pistillata.

Bacteria commonly form aggregates in a range of coral species [termed coral-associated microbial aggregates (CAMAs)], although these structures remain poorly characterized despite extensive efforts studying the coral microbiome. Here, we comprehensively characterize CAMAs associated with Stylophora pistillata and quantify their cell abundance. Our analysis reveals that multiple Endozoicomonas phylotypes coexist inside a single CAMA. Nanoscale secondary ion mass spectrometry imaging revealed that the Endozoicomonas cells were enriched with phosphorus, with the elemental compositions of CAMAs different from coral tissues and endosymbiotic Symbiodiniaceae, highlighting a role in sequestering and cycling phosphate between coral holobiont partners. Consensus metagenome-assembled genomes of the two dominant Endozoicomonas phylotypes confirmed their metabolic potential for polyphosphate accumulation along with genomic signatures including type VI secretion systems allowing host association. Our findings provide unprecedented insights into Endozoicomonas-dominated CAMAs and the first direct physiological and genomic linked evidence of their biological role in the coral holobiont.

Nanostructured electrochemical sensor applied to the electrocoagulation of arsenite in WWTP effluent

A sensitive electroanalytical method for the determination of arsenite, based on a heterostructure of aminated multiwalled carbon nanotubes and gold nanoparticles, was applied in an electrocoagulation (EC) treatment for the elimination of arsenite. A sensitive quantitative response was obtained in the determination of As3+ in a secondary effluent from a wastewater treatment plant from Santiago (Chile). The preconcentration stage was optimized through a Central Composite Face design, and the most sensitive peak current was obtained at 200 s and −600 mV of time and accumulation potential, respectively, after a differential pulse voltammetry sweep. Electroanalytical determination was possible in an interval between 42.89 and 170.00 μg L−1 with a detection limit of 0.39 μg L−1, obtaining recoveries over 99.1%. The developed method was successfully applied in an electrocoagulation treatment to remove 250 μg L−1 of arsenite from a polluted effluent in a batch system. Complete arsenite removal was achieved using a steel EC system with a current density of 6.0 mA cm−2 in less than 3 min of treatment.

Compositional features of Pb in agricultural soils and geochemical associations conditioning Pb contents in plants

Soil geochemical data is compositional. Hence the studies targeting the potential of accumulation of toxic elements (TE) in plants have to consider the compositional nature of soil chemical environment. In this study, the combined application of compositional data analysis and geospatial mapping was used to investigate Pb geochemical associations in agricultural soils, revealing the link between these associations and Pb contents in plants, as well as identifying source-specific transfer of Pb from soil to plants. The obtained results showed that soil chemical composition was conditioned by the geological peculiarities of the study area and the potential sources of chemical elements’ release. Particularly, k-means clustering and CoDa-biplot allows to identify three distinct subsamples and the application of HCA showed that both Pb soil and plants contents were in the same cluster in all subsamples. However, the geochemical association of elements in subsamples I and III suggested that Pb contents in plants were conditioned by the geochemical behaviors of carbonates whereas in subsample II Pb plant contents were presented in a geochemical association (K, Rb, Pb, and Zn) typical for both fertilizers and the potassium feldspar. The transfer factor (TF) for the comparatively higher values is observed for the subsample linked to K, Rb, Pb, and Zn geochemical association. At the same time, the negative influence of carbonates on the Pb availability in the plants was evidenced. The results of this study can serve as a good example for other investigations targeting the role of soil chemical elements compositional features in elements transfer to plant.

Multimedia distribution and ecological risk of bisphenol analogues in the urban rivers and their bioaccumulation in wild fish with different dietary habits

Bisphenol analogues (BPs) have been widely used in industrial production, and caused harmful effects on biological reproduction and development. The occurrence characteristics of six BPs in multi-matrices, including truly dissolved phase, colloids, suspended particulate matter (SPM), sediment and fish samples from urban river were investigated. Bisphenol A (BPA) and bisphenol S (BPS) were the mostly detected in six BPs in the Yangtze River (Nanjing section). The total average concentration of BPs was 393.8 ng/L in truly dissolved phase, 57.4 ng/L in colloids, 255.2 ng/g in SPM and 34.5 ng/g in sediment. The adsorption capacity of SPM and sediment to BPs were weaker than that of colloids. For the spatial variation, the concentrations of BPs in the surface water of the downstream of urban rivers were 1.3–1.6 times higher than that of the upstream, and the BPs concentrations in the sediments downstream of the sewage treatment plant were significantly higher than that in other sites. In wild fish, muscle has a high accumulative potential for BPs, followed by brain and liver tissues, and BPA was the dominant BPs in brain tissues. Furthermore, BPs concentration in muscle of wild fish with different feeding habits was in the following order: filter-feeding fish > omnivorous fish > herbivorous fish, and which was significantly positively correlated with BPs concentration in traditionally dissolved phase and colloidal phase. Meanwhile, BPs concentration in benthic herbivorous fish might be also controlled by the BPs adsorbed in the sediment. Ecological risk assessment was conducted and demonstrated that BPs might pose a moderate risk to fish, a low risk to algae and daphnias. The detected BPs does not pose a health risk to human trough drinking water and eating fish alone.

Risk Assessment of the Pesticide Coragen 20 SC with the Active Substance Chlorantraniliprole

Coragen 20 SC is a new product in Norway containing the active substance chlorantraniliprole. It is applied for use in apples against codling moth (Cydia pomonella), apple fruit moth (Argyresthia conjugella) and free leaf living larvae. The Norwegian Scientific Committee for Food Safety (VKM) was asked by the Norwegian Food Safety Authority to perform a risk assessment on human health, environmental fate and ecotoxicological of the active substance and the product. The risk assessment of the product was approved at a meeting 11th of May 2010 by VKMs Scientific Panel on Pesticides (Panel 2). VKMs Panel 2 concludes as following: The product and the active substance have low acute oral, dermal and inhalation toxicities. Both are non-irritating to the skin, and no allergenic potential by skin contact were shown. Coragen was non-irritating to the eyes, while chlorantraniliprole showed a weak irritating potential. Chlorantraniliprole is not shown to have any genotoxic or carcinogenic potential, or to be teratogenic or toxic to the reproduction of female animals. The potential for testicular toxicity of chlorantraniliprole is unclear because the study design and the limited number of young dogs (2/sex/group) do not provide basis for a firm conclusion. No particular target organ for toxicity in any species in the sub-chronic and chronic toxicity studies was seen. The observed dose- and time dependent increased degree of microvesiculation in the zona fasiculata of the adrenal cortex in male rats, is however of uncertain biological significance. All test species (rat, mice, dog) showed physiological adaption to chlorantraniliprole administration (increased liver metabolism with induction of cytochrome P450 enzymes) which was manifested as increased liver weight and hepatocellular hypertrophy. In the chronic toxicity study in mice, the increased liver weight and hepatocellular hypertophy was accompanied with eosinofilic foci, which was assessed as an adverse effect. The no observed effect level (NOAEL) derived from this study serves as basis for calculations of values for acceptable daily intake (ADI) and acceptable operator exposure level (AOEL). 
 In Panel 2‘s opinion a sub-chronic study (90 days) with the technical material (E2Y45-282) including relevant concentration of the impurity IN-G2S78 should be performed. This would bring information on possible influence of the impurity on the toxicological profile of the technical material, and consequently on the assessment of the NOAELs in the various toxic studies. 
 The estimated risk for operator and for bystanders or for workers re-entering treated crops is assessed as minimal. 
 Chlorantraniliprole is persistent in soil with half live of about 1 year. The long half life indicates high potential for accumulation in soil after repeated use, which is confirmed by both model simulations and field studies. The Panel considers field data from the south of Europe not to be relevant for the Nordic conditions based on different climate conditions and soil properties contributing in different directions.
 The Panel considers that the existing documentation is not sufficient for a firm conclusion on the use of normalised field data for modelling purposes. However, the substance is persistent and expected to accumulate in soil. The Panel concludes that there is minimal risk for toxic effects on mammals, birds, bees, and microorganisms in soil due to chlorantraniliprole exposure with the proposed exposure regime. Panel concludes that there is “very high risk” for effects on in-field non target arthropods from chlorantraniliprole exposure. 
 For soil living invertebrates, earthworms seem rather insensitive to chlorantraniliprole and the Panel considers the toxic effects to be minimal. Panel considers the risk for toxic effects on soil living arthropods to be high. Crustaceans and insects larvae are the aquatic organisms most sensitive to chlorantraniliprole. The Panel concludes that there is a minimal risk of toxic effects on aquatic organisms due to exposure to chlorantraniliprole with the proposed application regime provided that a buffer zone of 30 m to surface water is applied.

Investigation of Microplastic Exposure to Marine Fish in the Marine Tourism Area of Makassar City

Plastic waste pollution in the marine environment triggers the formation of microplastics dissolved in seawater. Microplastics are one of the nutrients for plankton and phytoplankton. Through the food chain, microplastics can accumulate in the bodies of marine biota, until they finally reach the human body. The purpose of this research is to investigate and determine the microplastic group in fish in Makassar City KWB destinations. The method applied is maceration extraction using 70% C2H­5OH for 3 days, then extracted with N-Hexane. The non-polar extracts identified the microplastic components using FTIR spectroscopy and analyzed the types of microplastics based on their absorption spectrum images. The results of the study were that all fish samples coded PS.B.1, PS.B.2, PS.B.3, were contaminated with secondary microplastics. Types of microplastics were identified, namely PP, PVC, PE, PS, PET and PC. The microplastic contaminants are thought to be the result of community activities. The public needs to be aware of the potential for microplastic accumulation in the bodies of marine fish that are consumed. Managers of Makassar City KWB destinations are advised to apply a pattern of supervision to the community to care about waste and educate the implementation of plastic waste recycling management

Early Drug-Induced Liver Injury Risk Screening: “Free,” as Good as It Gets

Abstract For all the promise of and need for clinical drug-induced liver injury (DILI) risk screening systems, demonstrating the predictive value of these systems versus readily available physicochemical properties and inherent dosing information has not been thoroughly evaluated. Therefore, we utilized a systematic approach to evaluate the predictive value of in vitro safety assays including bile salt export pump transporter inhibition and cytotoxicity in HepG2 and transformed human liver epithelial along with physicochemical properties. We also evaluated the predictive value of in vitro ADME assays including hepatic partition coefficient (Kp) and its unbound counterpart because they provide insight on hepatic accumulation potential. The datasets comprised of 569 marketed drugs with FDA DILIrank annotation (most vs less/none), dose and physicochemical information, 384 drugs with Kp and plasma protein binding data, and 279 drugs with safety assay data. For each dataset and combination of input parameters, we developed random forest machine learning models and measured model performance using the receiver operator characteristic area under the curve (ROC AUC). The median ROC AUC across the various data and parameters sets ranged from 0.67 to 0.77 with little evidence of additive predictivity when including safety or ADME assay data. Subsequent machine learning models consistently demonstrated daily dose, fraction sp3 or ionization, and cLogP/D inputs produced the best, simplest model for predicting clinical DILI risk with an ROC AUC of 0.75. This systematic framework should be used for future assay predictive value assessments and highlights the need for continued improvements to clinical DILI risk annotation.

Assessment of the antioxidative response and culturable micro-organisms of Lygeum spartum Loefl. ex L. for prospective phytoremediation applications

Abundant plant species in arid industrial areas are mining phyto-resources for sustainable phyto-management. However, the association with their rhizosphere is still poorly known for phytoremediation purposes. This study aims to assess the heavy metals (HMs) and metalloids uptake of Lygeum spartum Loefl. ex L. growing in cement plant vicinity and screen associated culturome for potential phytoremediation use. Bioaccumulation factor (BAF), the translocation factor (TF), and the mobility ratio (MR) were studied along with four sites. Lipid peroxidation (MDA), free proline (Pro), Non-protein thiols (NPTs), and reduced glutathione (GSH) were tested for evaluating the plant antioxidative response. Bacteria and fungi associated with L. spartum Loefl. ex L. were identified by 16S rRNA and fungal internal transcribed spacer (ITS1-ITS2) gene sequencing. Our results showed an efficient uptake of As, Pb, and Zn and enhanced GSH (0.34 ± 0.03) and NPTs (528.7 ± 14.4 nmol g−1 FW) concentrations in the highly polluted site. No significant variation of Arbuscular Mycorrhizal Fungi (AMF) was found. Among 29 bacterial isolates, potential bioremediation were Bacillus simplex and Bacillus atrophaeus. Thus, L. spartum Loefl. ex L. and its associated microbiota have the potential for phytoremediation applications. Novelty statement: This work has been set in line with the investigation of the integrative biology of Lygeum spartum Loefl ex L. and the screening of its associated microbiome for potential phytoremediation applications. This work is the first work conducted in a cement plant vicinity investigating the associated fungi and bacteria of L. spartum Loefl. ex L. and been part of a sectorial research project since 2011, for assessing the impact of industrial pollution and recognizing the accumulation potential of plant species for further phyto-management applications.

Tea polyphenols mediated Zero-valent Iron/Reduced graphene oxide nanocomposites for electrochemical determination of Hg2+

Herein, we have developed a chemically modified glassy carbon electrode (GCE) using tea polyphenols mediated zero-valent iron/reduced graphene oxide nanocomposites (rGO-ZVI-P) for rapid determination of Hg2+ in water. Highly conductive rGO-ZVI-P were fabricated by a green chemical method using tea polyphenols as the reductant. The rGO-ZVI-P shows a unique affinity to aqueous Hg2+ due to a synergy between ZVI and rGO. The rGO-ZVI-P electrochemical sensor shows optimal performance for Hg2+ determination in pH 5.00 phosphate buffer and 180 s accumulation time at −1.2 V accumulation potential used under square wave anode stripping voltammetry (SWASV). At these conditions, the Hg2+ determination sensitivity is 41.42 μA/μM and the determination limit is 1.2 nM. There are no interferences to the rGO-ZVI-P modified GCE sensor in the presence of 0.5 μM Cd2+, 0.5 μM Pb2+, and 0.5 μM Cu2+ in solution, either in discrete cations or multi-cations modes. Moreover, the typical chemical species found in the matrix of river water samples do not interfere with the as-fabricated Hg2+ electrochemical sensor. The Hg2+ determination by the rGO-ZVI-P modified GCE sensor is repeatable, stable, and robust, and it has potential in environmental applications.

SEASONAL VARIATIONS OF HEAVY METAL CONTENTS IN THE NEEDLES OF SOME EVERGREEN TREES IN GREEN SPACES OF YEREVAN (ARMENIA)

The main aim of this research was to study a metal accumulation potential of two evergreen species Thuja occidentalis L. and Juniperus virginiana in different periods of plant vegetation in Yerevan. The total contents of 6 microelements: Pb, Cd, Ni, Zn, Cu, Mo in plant material were determined by atomic absorption spectrometry (A Analyst 800, Perkin Elmer, USA). The research results have proved that metal concentrations in the needles of evergreen trees are variable depending on a vegetation period and disposition relative to roads with heavy traffic and industrial pollution sources. The concentrations of the studied elements in the needles did not exceed the standard values both in summer and winter, except Mo, which was high in both species nearby industrial pollution sources. The total average contents of metals in the needles increase in winter.

Long-term orchard practice affects the ecological and human health risk of soil heavy metals in a calcareous environment.

The contamination of agroecosystems with heavy metals, caused by the long-term agricultural practices (e.g., the application of extensive agrochemical), has become a high-priority issue for soil-food-human health. Our study aimed to estimate the effect of the agricultural activities on contamination severity and health risk potential of heavy metals in the soil-urban apple orchards versus control soils across various soil types and apple cultivars. This research assessed pollution index (PI), pollution load index (PLI), ecological risk (ER), bio-concentration factor (BCF), hazard quotient (HQ), and overall hazard index (HI). The results revealed a significant increase in the concentration of all metals of the orchard soils, ranging 30-51%, 19-24%, 70-137%, 25-33%, and 16-23% for Zn, Cu, Cd, Pb, and Ni, respectively, versus those in the control soils. Compared to the control soils, PI, PLI, and ER reflected a significant increase in the orchard soils ranging 13-67%, 18-45%, and 18-33%, respectively, which has downgraded their scoring class by one grade. Cd and Pb were not detected in the samples collected from the apple cultivars 'Golden Delicious' (GD) and 'Red Delicious' (RD), indicating no toxic levels of Cd and Pb. Compared to the GD, the concentration of Zn, Cu, and Ni was comparatively higher in RD, implying varying heavy metal accumulation potentials in two different apple cultivars. The mean HQ and HI were in the low category (0.1 ≤ HQ and HI < 1) in both GD and RD cultivars, meaning that GD and RD are safe for local residents to be consumed and do not pose a significant potential risk to the health of consumers. However, HQ and HI were significantly higher in the RD cultivar than in the GD cultivar in most apple samples.

Adrenaline biosensors based on r Go/Ag nanocomposites functionalized textiles using advanced electron beam irradiation technique

This study developed flexible textile biosensors based on rGO/Ag nanocomposite to detect adrenaline (epinephrine). Reduced graphene oxide (rGO) and Ag nanoparticles (NPs) were obtained in a single step using the electron-beam irradiation technique, a rapid, efficient, plain, ecofriendly, and easily scalable procedure. The nanocomposites’ properties were characterized by ultraviolet–visible-light spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Furthermore, the obtained sensors’ electrochemical behaviors of epinephrine were investigated using square wave voltammetry (SWV), linear sweep voltammetry, and differential pulse voltammetry methods. The optimum experimental conditions included pH 7, phosphate borate buffer, accumulation time of 100 s, accumulation potential of 0.4 V, and a scan rate of 100mV/s. In addition, the anodic peak currents of epinephrine by SWV were 16.33 and 13.9 µA for rGO/AgNP/cotton and rGO/AgNP/polyester, respectively. The fabricated flexible textile biosensors exhibited high sensitivity and strong catalytic activity for epinephrine detection. Under optimal testing conditions, in the range of 0.5–100.0 µL, two detection lines and a low limit of detection (LOD) of 9.73 nM (S/N = 3) for epinephrine were obtained for cotton and polyester biosensors. Two wide detection ranges were observed at 0.5–40.0 µL for cotton biosensors, whereas there was a lower LOD of 3.05 nM (S/N = 3) at 1.0–30 µL for polyester biosensors. Overall, the constructed electrode can serve as a promising analytical sensor for adrenaline determination in pharmaceutical and biological samples.

Hydrogeochemical analysis of groundwater quality for drinking and irrigation with elevated arsenic and potential impact on agro-ecosystem in the upper Brahmaputra plain, India.

The upper Brahmaputra floodplain is considerably enriched with geogenic contaminants, mainly Arsenic (As) exhibiting high spatial heterogeneity. With this concern, the present study was conducted in Lakhimpur district located in the upper Brahmaputra floodplain aiming to assess the groundwater (GW) suitability for drinking and irrigation. Chemical analysis of 78 GW samples revealed significantly high As (max 0.12 mgL-1, mean 0.02 mgL-1) followed by iron (max 62.2 mgL-1, mean 19.94 mgL-1) showing uneven distribution. Hydrogeochemical analysis of the GW samples revealed that majority of the water samples belong to mixed Ca2+- Na+- HCO3- type with weathering and forward ion exchange as the dominant processes in the aquifer system. Positive correlation among iron (Fe) and As, together with close grouping in hierarchical cluster analysis and principal components analysis, indicated the involvement of reductive hydrolysis process. Calculation of saturation indices indicated that, precipitation of Fe minerals may lead to de-coupling of Fe and As contributing to the enrichment of both the elements in the GW. Further, assessment of key parameters for irrigation water quality including water quality index indicated the GW to be suitable for irrigation purpose. Finally, toxicity implications of crops produced from As contaminated water indicated higher accumulation potential of As in the food grains implying significant impacts on the agro-ecosystem and associated health hazards.

Assessment of phthalate esters (PAEs) contamination in Urtica dioica L.

Phthalate esters are a group of chemical compounds of ubiquitous nature which nowadays have become a colossal threat to the environment, human-animal and plant health, because of its higher potential of accumulation in soil and aquatic habitat leading to environmental contamination due to its widespread industrial and agricultural usage. The present research aims to analyze the phthalate esters accumulation in Urtica dioica L. For this study, the Urtica dioica is tested for the presence of phthalates by using Gas Chromatography-Mass spectrometry. The Gas Chromatography-Mass spectrometry observations show the presence of 11 phthalate esters, among which diethyl phthalate (DEP) and bis(2-ethylhexyl) phthalate (BEHP), dibutyl phthalate (DBP), and diisobutyl phthalate (DIBP) were found to be in significantly higher amount. The sum concentrations of the phthalate ester in different extracts of plant range from 16.25% to 84.07%. The % composition of diethyl phthalate is found to be comparatively higher than other phthalate esters in methanolic extract of Urtica dioica while diisobutyl phthalate and bis (2-ethylhexyl) phthalate accumulation is found relatively higher in the ethyl acetate and diethyl ether fractions. The observations show the contamination of the Urtica dioica plant with phthalate esters and also indicate the phthalate accumulating potential of the plant.

Elevated urbanization-driven plant accumulation and human intake risks of polycyclic aromatic hydrocarbons in crops of peri-urban farmlands.

As an ubiquitous carcinogen, polycyclic aromatic hydrocarbons (PAHs) are closely related to anthropogenic activities. The process of urbanization leads to the spatial interlacing of farmlands and urbanized zones. However, field evidence on the influence of urbanization on the accumulation of PAHs in crops of peri-urban farmlands is lacking. This study comparatively investigated the urbanization-driven levels, compositions, and sources of PAHs in 120 paired plant and soil samples collected from the Yangtze River Delta in China and their species-specific human intake risks. The concentrations of PAHs in crops and soils in the peri-urban areas were 2407.92ngg-1 and 546.64ngg-1, respectively, which are significantly higher than those in the rural areas. The PAHs in the root were highly relevant to those in the soils (R2 = 0.63, p < 0.01), and the root bioconcentration factors were higher than 1.0, implying the contributions of root uptake to plant accumulations. However, the translocation factors in the peri-urban areas (1.57 ± 0.33) were higher than those in the rural areas (1.19 ± 0.14), indicating the enhanced influence through gaseous absorption. For the congeners, the 2- to 3-ring PAHs showed a higher plant accumulation potential than the 4- to 6-ring PAHs. Principal component analysis show that the PAHs in the peri-urban plants predominantly resulted from urbanization parameters, such as coal combustion, vehicle emissions, and biomass burning. The mean values of estimated dietary intake of PAHs from the consumption of peri-urban and rural crops were 9116ngday-1 and 6601.83ngday-1, respectively. The intake risks of different crops followed the order rice > cabbage > carrot > pea. Given the significant input of PAHs from urban to farmland, the influence of many anthropogenic pollutants arising from rapid urbanization should be considered when assessing the agricultural food safety.

Phenotypic variations of wheat cultivars from the North China Plain in response to cadmium stress and associated single nucleotide polymorphisms identified by a genome-wide association study

Understanding the genetic mechanisms for cadmium (Cd) uptake and translocation in common wheat (Triticum aestivum) is of significance in food Cd contamination control. In this study, a diverse panel of 132 wheat cultivars was collected from the North China Plain. The cultivars were evaluated in terms of their phenotypic variations in response to Cd stress and subjected to a genome-wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with the phenotypic variations at the seedling stage. Significant phenotypic variations with high heritability were observed among the wheat cultivars exposed to 40 μmol L-1 Cd for the studied traits, including root length (RL), shoot length (SL), root and shoot dry biomasses (RDW and SDW, respectively), root and shoot Cd concentrations (RCD and SCD, respectively), and Cd translocation factor (TF). Mean RCD, SCD, and TF ranged from 1.0 to 33.8, 0.125 to 2.022, and 0.009 to 0.321 mg g-1, respectively. Cluster analysis showed that wheat cultivars with higher RL, SL, RDW, and SDW under Cd stress were able to accumulate more Cd in root, leading to a lower Cd TF. Mixed linear model-based association analysis detected 17 novel significant marker-trait associations (MTAs), four of which were significant at a genome-wide scale. Most of the significant MTAs controlled Cd TF and explained 17.17%–26.47% of the phenotypic variations. Some of the SNP loci were physically close to a reported Cd-related quantitative trait locus or gene on wheat chromosomes. Results of this study provided a list of wheat cultivars with the potential of low Cd accumulation and enriched our knowledge on the genetic basis of Cd uptake and translocation in wheat. Pyramiding breeding of superior alleles detected in this study may additionally reduce Cd accumulation of improved wheat cultivars with excellent agronomic traits.

Application of Molecularly Imprinted Poly-Itaconic/Multiwalled Carbon Nanotubes for Selective and Sensitive Electrochemical Detection of Linagliptin

In this work, we report the first molecularly imprinted polymer (MIP) based electrochemical sensor for the determination of the antidiabetic drug Linagliptin (LNG) in pure sample, tablets, and spiked human urine and serum samples. Using a graphite electrode, differential pulse voltammetry (DPV) was applied to study the electrochemical behavior of LNG in a Britton Robinson (BR) universal buffer of pH 8 with Ag/AgCl electrode and Pt wire. The sensor is based on the modification of the traditional carbon paste sensor with Itaconic acid (IA) as monomer, which cross-linked using ethylene glycol dimethacrylate (EGDMA) and multiwalled carbon nanotubes (MWCNTs) as a modifier. The different factors were optimized, such as ratio of MIP components, percentage of multiwalled carbon nanotubes (MWCNT), pH, accumulation time, accumulation potential and scan rate. The proposed sensor was characterized morphologically using: Scanning electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET) and electrochemically applying electrochemical impedance spectroscopy (EIS)and cyclic voltammetry (CV). DPV was applied to obtain the calibration curve and optimization of different factors, the proposed sensor shows a wide linear range of 1 × 10−12M (0.47 ng l−1) to 1 × 10−7M (47.26 μg l−1) and limit of detection (LOD)1 × 10−13M (0.05 ng l−1) while the limit of quantification (LOQ)was found to be 3.3 × 10−13M (0.16 ng l−1) in addition to good reproducibility and selectivity.

In-situ electrochemical and piezogravimetric studies on the application of macrocyclic resorcinarene tetramer in the development of chemically-modified heavy metals ions detection platform in aqueous media

The new application of C-dec-9-enylcalix[4]resorcinarene ( R 1 ), as an ionophore to detect heavy metals (HMs) cations (Cd 2+ , Hg 2+ , Cu 2+ , and Pb 2+ ) in the aqueous media has been investigated through the preparation of an effective mass-sensitive sensor via the exploitation of a flow-type QCM-I technique. By adjusting the ions’ amounts in model solutions over a wide range of concentrations, acquired changes in the oscillating frequency related to the loading of metal ions on the sensor’s surface were gained, and thus favorable metrological parameters displaying the lowest detection limit (LOD) associated with copper ions (10 ppb). Simultaneously, a novel voltammetric sensor was prepared by modifying gold screen-printed electrodes (SPEs) with R 1 . Electrochemical characterization employing CV, SWV, and EIS was carried out, showing the success of the electrode modification. Then, the experimental conditions of supporting electrolyte, pH, accumulation time, and accumulation potential were optimized to achieve an enhanced detection. The R 1 @SPE sensor simultaneously detected the HMs (Cd 2+ , Hg 2+ , Cu 2+ , Pb 2+ ), and the lowest LOD was associated with Pb 2+ (0.19 ppb). The selectivity evaluation of the electrochemical sensor was performed by studying the effect of interferences majorly present in water sources (Mg 2+ , Ni 2+ , Zn 2+ , Al 3+ , and K + ) on the SWV detection signals, and it was revealed that the interfering ions did not affect the simultaneous detection of the studied HMs (RSD less than 5%), the voltammetric sensors also presented excellent repeatability and reproducibility (RSD less than 5%).

Potential of damage accumulation during segmented rotor blade fatigue tests

Modern wind turbines have higher rated power and improved capacity factors. This results in very long and slender blades which are also designed closer to the material limits. As a consequence, blade test facilities need to be upgraded for static and fatigue full-scale blade testing to carry larger loads and deal with larger tip deflections. Another aspect is the adaption of the test methods to avoid high overloads, which can cause premature damage and require time-consuming repairs. One drawback of traditional full-scale tests with a full-length rotor blade is the long time needed for certification as the blades have low eigenfrequencies and hence high fatigue test durations. This work presents an alternative fatigue testing approach for rotor blades which combines full-length and segmented fatigue tests, each contributing to the accumulated fatigue damage. The proposed approach is benchmarked with the traditional approach by means of a numerical optimization study. applying this approach to a current offshore rotor blade design illustrates the potential for reducing the fatigue test duration by 66% and the local fatigue damage overload to a mere fraction.

Is Glacial Meltwater a Secondary Source of Legacy Contaminants to Arctic Coastal Food Webs?

Climate change-driven increases in air and sea temperatures are rapidly thawing the Arctic cryosphere with potential for remobilization and accumulation of legacy persistent organic pollutants (POPs) in adjacent coastal food webs. Here, we present concentrations of selected POPs in zooplankton (spatially and seasonally), as well as zoobenthos and sculpin (spatially) from Isfjorden, Svalbard. Herbivorous zooplankton contaminant concentrations were highest in May [e.g., ∑polychlorinated biphenyls (8PCB); 4.43, 95% CI: 2.72–6.3 ng/g lipid weight], coinciding with the final stages of the spring phytoplankton bloom, and lowest in August (∑8PCB; 1.6, 95% CI: 1.29–1.92 ng/g lipid weight) when zooplankton lipid content was highest, and the fjord was heavily impacted by sediment-laden terrestrial inputs. Slightly increasing concentrations of α-hexachlorocyclohexane (α-HCH) in zooplankton from June (1.18, 95% CI: 1.06–1.29 ng/g lipid weight) to August (1.57, 95% CI: 1.44–1.71 ng/g lipid weight), alongside a higher percentage of α-HCH enantiomeric fractions closer to racemic ranges, indicate that glacial meltwater is a secondary source of α-HCH to fjord zooplankton in late summer. Except for α-HCH, terrestrial inputs were generally associated with reduced POP concentrations in zooplankton, suggesting that increased glacial melt is not likely to significantly increase exposure of legacy POPs in coastal fauna.