scholarly journals Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

2002 ◽  
Vol 2 ◽  
pp. 707-729 ◽  
Author(s):  
Scott J. Markich
Keyword(s):  
Surface Waters ◽  
Metal Ion ◽  
Natural Waters ◽  
Analytical Techniques ◽  
Time Resolved ◽  
Analytical Technique ◽  
Major Form ◽  
Uranyl Carbonate ◽  
Inorganic Ligands ◽  
The Relationship

The speciation of uranium (U) in relation to its bioavailability is reviewed for surface waters (fresh- and seawater) and their sediments. A summary of available analytical and modeling techniques for determining U speciation is also presented. U(VI) is the major form of U in oxic surface waters, while U(IV) is the major form in anoxic waters. The bioavailability of U (i.e., its ability to bind to or traverse the cell surface of an organism) is dependent on its speciation, or physicochemical form. U occurs in surface waters in a variety of physicochemical forms, including the free metal ion (U4+or UO22+) and complexes with inorganic ligands (e.g., uranyl carbonate or uranyl phosphate), and humic substances (HS) (e.g., uranyl fulvate) in dissolved, colloidal, and/or particulate forms. Although the relationship between U speciation and bioavailability is complex, there is reasonable evidence to indicate that UO22+and UO2OH+are the major forms of U(VI) available to organisms, rather than U in strong complexes (e.g., uranyl fulvate) or adsorbed to colloidal and/or particulate matter. U(VI) complexes with inorganic ligands (e.g., carbonate or phosphate) and HS apparently reduce the bioavailability of U by reducing the activity of UO22+and UO2OH+. The majority of studies have used the results from thermodynamic speciation modeling to support these conclusions. Time-resolved laser-induced fluorescence spectroscopy is the only analytical technique able to directly determine specific U species, but is limited in use to freshwaters of low pH and ionic strength. Nearly all of the available information relating the speciation of U to its bioavailability has been derived using simple, chemically defined experimental freshwaters, rather than natural waters. No data are available for estuarine or seawater. Furthermore, there are no available data on the relationship between U speciation and bioavailability in sediments. An understanding of this relationship has been hindered due to the lack of direct quantitative U speciation techniques for particulate phases. More robust analytical techniques for determining the speciation of U in natural surface waters are needed before the relationship between U speciation and bioavailability can be clarified.

The persistence and transformation of silver nanoparticles in littoral lake mesocosms monitored using various analytical techniques

2014 ◽  
Vol 11 (4) ◽  
pp. 419 ◽  
Author(s):  
Lindsay M. Furtado ◽  
Md Ehsanul Hoque ◽  
Denise M. Mitrano ◽  
James F. Ranville ◽  
Beth Cheever ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Surface Waters ◽  
Lake Water ◽  
Natural Waters ◽  
Municipal Wastewater ◽  
Analytical Techniques ◽  
Aquatic Organisms ◽  
Silver Ions ◽  
Icp Ms ◽  
The Individual

Environmental context Silver nanoparticles discharged with municipal wastewater may contaminate surface waters and harm aquatic ecosystems. We applied several analytical techniques to investigate the persistence and transformation of silver nanoparticles in a natural lake environment, and show, through multiple lines of evidence, that they persisted in lake water for several weeks after addition. The nanoparticles were releasing silver ions through dissolution, but these toxic ions were likely binding with natural organic matter in the lake water. Abstract Silver nanoparticles (AgNPs) may be released into surface waters, where they can affect aquatic organisms. However, agglomeration, dissolution, surface modifications and chemical speciation are important processes that control the toxicity of AgNPs. The purpose of the study was to apply various methods for monitoring the persistence and transformation of AgNPs added to littoral lake mesocosms. Analysis of total Ag showed that the levels in the mesocosms declined rapidly in the first 12h after addition, followed by a slower rate of dissipation with a half-life (t1/2) of ~20 days. Analysis using single particle ICP-MS (spICP-MS) showed no evidence of extensive homo-agglomeration of AgNPs. The stability of AgNPs was likely due to the low ionic strength and high concentrations of humic-rich dissolved organic carbon (DOC) in the lake water. Analyses by spICP-MS, cloud point extraction (CPE) and asymmetric flow field flow fractionation coupled to ICP-MS (AF4-ICP-MS) all indicated that the concentrations of AgNP decreased over time, and the nanoparticles underwent dissolution. However, the concentrations of dissolved silver, which includes Ag+, were generally below detection limits when analysed by centrifugal ultrafiltration and spICP-MS. It is likely that the majority of free ions released by dissolution were complexing with natural organic material, such as DOC. An association with DOC would be expected to reduce the toxicity of Ag+ in natural waters. Overall, we were able to characterise AgNP transformations in natural waters at toxicologically relevant concentrations through the use of multiple analytical techniques that compensate for the limitations of the individual methods.

scholarly journals Peran CSR Awards terhadap Citra Perusahaan dalam Komunikasi Antar Budaya

InterKomunika ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 30
Author(s):  
Susi Andrini
Keyword(s):  
Intercultural Communication ◽  
Quantitative Research ◽  
Analytical Techniques ◽  
Corporate Image ◽  
Process Data ◽  
Analytical Technique ◽  
Qualitative Descriptive ◽  
Corporate Social ◽  
The Relationship

This study aims to study empirically the influence of Corporate Social Responsibility (CSR) Awards on Corporate Image in intercultural communication, for CSR Indonesia Summit & Awards 2018 case study conducted by MePRindo Communication and Media CSR-Indonesia. The sample used in this study there are 75 respondents taken from participants in the event. The method used in this study is observation (observation) with the type of research and qualitative descriptive qualitative. This study aims to reveal the facts, circumstances, phenomena, variables and circumstances that occur when the study runs. The purpose of this study is to find out how researchers can process the results of research by analyzing the relationship or the relationship between the two, on research CSR Award role against corporate / corporate image in intercultural communication, with quantitative and qualitative descriptive approach. This method is suitable because it only provides an overview of research related to the role of csr awards to corporate image in case study (CSR Indonesia Summit & Awards 2018). Data collection techniques were conducted through the observation stage, questionnaire distribution, interview and documentation study. The analytical technique used in this study, is quantitative and qualitative descriptive. Analytical techniques used in this study, is descriptive quantitative and qualitative. Quantitative research is intended to process data in the field then distribute it into the form of frequency / percentage tabulation, while to deepen the results of quantitative research conducted with qualitative research. The results of the research findings are to obtain in-depth results in analyzing or interpreting the data obtained from the results of the study.

Recent Developments in CE-MS Based Metabolomics

2020 ◽  
Vol 16 ◽  
Author(s):  
Mustafa Çelebier ◽  
Merve Nenni
Keyword(s):  
Sample Preparation ◽  
Scientific Information ◽  
Analytical Techniques ◽  
Living Organism ◽  
Analytical Technique ◽  
Ionic Compounds ◽  
Recent Sample ◽  
Recent Developments ◽  
Endogenous Metabolites ◽  
Preparation Techniques

Background: Metabolomics has gained importance in clinical applications over the last decade. Metabolomics studies are significant because the systemic metabolome is directly affected by disease conditions. Metabolome-based biomarkers are actively being developed for early diagnosis and to indicate the stage of specific diseases. Additionally, understanding the effect of an intervention on a living organism at the molecular level is a crucial strategy for understanding novel or unexpected biological processes. Results: The simultaneous improvements in advanced analytical techniques, sample preparation techniques, computer technology, and databank contents has enabled more valuable scientific information to be gained from metabolomics than ever before. With over 15,000 known endogenous metabolites, there is no single analytical technique capable of analyzing the whole metabolome. However, capillary electrophoresis-mass spectrometry (CE-MS) is a unique technique used to analyze an important portion of metabolites not accessible by liquid chromatography or gas chromatography techniques. The analytical capability of CE, combined with recent sample preparation techniques focused on extracting polar-ionic compounds, make CE-MS a perfect technique for metabolomic studies. Conclusion: Here, previous reviews of CE-MS based metabolomics are evaluated to highlight recent improvements in this technique. Specifically, we review papers from the last two years (2018 and 2019) on CE-MS based metabolomics. The current situation and the challenges facing metabolomic studies are discussed to reveal the high potential of CE-MS for further studies, especially in biomarker development studies.

scholarly journals Impact of Environmental Moral Education on Pro-Environmental Behaviour: Do Psychological Empowerment and Islamic Religiosity Matter?

2021 ◽  
Vol 18 (4) ◽  
pp. 1604
Author(s):  
Abida Begum ◽  
Liu Jingwei ◽  
Maqsood Haider ◽  
Muhammad Maroof Ajmal ◽  
Salim Khan ◽  
...  
Keyword(s):  
Moral Education ◽  
Structural Equation ◽  
Psychological Empowerment ◽  
Analytical Techniques ◽  
Cross Sectional ◽  
Environmental Behaviour ◽  
Mediating Role ◽  
Global Environmental Problems ◽  
Global Environmental ◽  
The Relationship

In light of increasing concerns about global environmental problems, environmental moral education is assumed to have a significant influence on the pro-environmental behaviour of students. Within the past decade, several higher education institutes have acknowledged the importance of integrating sustainability into the educational curriculum to have a focused and explicit impact on society. The current study investigated the relationship between environmental moral education and pro-environmental behaviour while drawing upon insights from the conservation of resource theory. The relationship among the aforementioned variables was studied for the mediating role of psychological empowerment and the moderating effect of Islamic religiosity. Data were collected from 429 university students with a cross-sectional approach. The data were analysed using “structural equation modelling” and “PROCESS” analytical techniques. The results of the study followed the predicted conceptual model, that is, environmental moral education was positively related to pro-environmental behaviour. Furthermore, psychological empowerment partially mediated the aforementioned relationship, while Islamic religiosity moderated the relationships between environmental moral education and pro-environmental behaviour as well as between environmental moral education and psychological empowerment. These findings reinforce the importance of environmental moral education and Islamic religiosity in understanding the Muslim student’s ecological behaviours.

Biodegradation studies as an important way to estimate the environmental fate of chemicals

1999 ◽  
Vol 39 (10-11) ◽  
pp. 375-382
Author(s):  
Andreja Žgajnar Gotvajn ◽  
Jana Zagorc-Končan
Keyword(s):  
Surface Waters ◽  
Natural Waters ◽  
Environmental Fate ◽  
Standard Test ◽  
Screening Tests ◽  
Natural Systems ◽  
Additional Information ◽  
Assessment Tests ◽  
Ready Biodegradability ◽  
Biodegradability Assessment

Biodegradation is confirmed as an important mechanism of organic chemicals removal in natural systems. Estimation of biodegradability of chemicals which reach the aquatic environment in significant or even negligible quantities is necessary in assessing the entire hazard associated with their use. The aim of our study was to compare the standardized ready biodegradability assessment test (closed bottle test) and its modifications, employing the basic agreements on test principles of simulation of biodegradation in surface waters, yet no official standard method has been adopted. The standard test was modified using various natural river waters and a variety of nutrient conditions and microbial species trying to simulate the natural environment in the simplified way. Tests were performed with two compounds with different ability to degrade. Experiments indicate that predictability of biodegradation obtained by ready biodegradability assessment tests for surface waters in many cases is not reliable, because of different conditions, which may prevail in surface waters over time and affect biodegradation. However, the use of natural waters in screening tests assures additional information on fate of chemicals in rivers and lakes.

scholarly journals Mycotoxin Analysis: New Proposals for Sample Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Natalia Arroyo-Manzanares ◽  
José F. Huertas-Pérez ◽  
Ana M. García-Campaña ◽  
Laura Gámiz-Gracia
Keyword(s):  
Raw Materials ◽  
Animal Health ◽  
Analytical Techniques ◽  
Sample Treatment ◽  
Analytical Technique ◽  
Chemical Structures ◽  
Technical Developments ◽  
Food And Feed ◽  
Ultrahigh Performance Liquid Chromatography ◽  
Food Commodities

Mycotoxins are toxic secondary metabolites produced by different fungi, with different chemical structures. Mycotoxins contaminate food, feed, or raw materials used in their production and cause diseases and disorders in humans and livestock. Because of their great variety of toxic effects and their extreme heat resistance, the presence of mycotoxins in food and feed is considered a high risk to human and animal health. In order to ensure food quality and health consumers, European legislation has set maximum contents of some mycotoxins in different matrices. However, there are still some food commodities susceptible to fungal contamination, which were not contemplated in this legislation. In this context, we have developed new analytical techniques for the multiclass determination of mycotoxins in a great variety of food commodities (some of them scarcely studied), such as cereals, pseudocereals, cereal syrups, nuts, edible seeds, and botanicals. Considering the latest technical developments, ultrahigh performance liquid chromatography coupled to tandem mass spectrometry has been chosen as an efficient, fast, and selective powerful analytical technique. In addition, alternative sample treatments based on emerging methodologies, such as dispersive liquid-liquid microextraction and QuEChERS, have been developed, which allow an increased efficiency and sample throughput, as well as reducing contaminant waste.

Assessing the relationship between the abundance of microplastics in sediments, surface waters, and fish in the Iran southern shores

2021 ◽  
Author(s):  
Ali Agharokh ◽  
Mojtaba S. Taleshi ◽  
Mehdi Bibak ◽  
Majid Rasta ◽  
Hor Torabi Jafroudi ◽  
...  
Keyword(s):  
Surface Waters ◽  
The Relationship

scholarly journals Commentary on Ivancic et al.: Enzyme kinetics from circular dichroism of insulin reveals mechanistic insights into the regulation of insulin-degrading enzyme

2018 ◽  
Vol 38 (6) ◽  
Author(s):  
Giuseppe Grasso
Keyword(s):  
Analytical Techniques ◽  
Label Free ◽  
Insulin Degrading Enzyme ◽  
Degrading Enzyme ◽  
Analytical Technique ◽  
Biochemical Pathways ◽  
New Methods ◽  
The World ◽  
Free Environment ◽  
Enormous Number

Despite the enormous number of therapeutic advances in medicine, nowadays many diseases are still incurable, mainly due to the lack of knowledge of the pathological biochemical pathways triggering those diseases. For this reason, it is compulsory for the scientific community to investigate and unveil the biomolecular mechanisms responsible for the development of those diseases, such as Alzheimer’s disease and diabetes, which are widespread all over the world. In this scenario, it is of paramount importance to develop new analytical techniques and experimental procedures that are capable to make the above-mentioned investigations feasible. These new methods should allow easy performable analysis carried out in a label-free environment, in order to give reliable answers to specific biochemical questions. A recent paper published on Bioscience Reports by Ivancic et al. (https://doi.org/10.1042/BSR20181416) proposes a new analytical technique capable to reveal some mechanistic insights into the regulation of insulin-degrading enzyme (IDE), a protein involved in the above-mentioned diseases. IDE is a multifaceted enzyme having different and not well-defined roles in the cell, but it is primarily a proteolytic enzyme capable to degrade several different amyloidogenic substrates involved in different diseases. Moreover, many molecules are responsible for IDE activity modulation so that understanding how IDE activity is regulated represents a very challenging analytical task. The new analytical approach proposed by Ivancic et al. reports on the possibility to study IDE activity in an unbiased and label-free manner, representing a valid alternative assay for the investigation of any proteases degradative activity.

Relationship between Pseudomonas aeruginosa and Bacterial Indicators in Polluted Natural Waters

1991 ◽  
Vol 24 (2) ◽  
pp. 121-124 ◽  
Author(s):  
A. de Vicente ◽  
J. C. Codina ◽  
P. Romero
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Natural Waters ◽  
Pollution Index ◽  
Close Correlation ◽  
Aquatic Environments ◽  
Faecal Coliforms ◽  
Faecal Pollution ◽  
The Relationship ◽  
Faecal Indicators ◽  
Faecal Streptococci

The relationship between Pseudomonas aeruginosa and the faecal pollution index (total coliforms, faecal coliforms and faecal streptococci) in natural waters was established. Water samples were collected from several aquatic environments in Málaga (Spain). P. aeruginosa counts and isolation frequencies were clearly associated with the degree of faecal pollution of the studied water. The results confirmed that domestic sewage was the major source of P. aeruginosa in river and seawater, being isolated from sewage at concentrations about 105 cfu/100 ml. There was a close correlation between the P. aeruginosa concentration and the densities of the three faecal indicators in both river and marine waters. A significant correlation was not observed in waters with little faecal pollution because P. aeruginosa was only occasionally isolated from these waters and at very low densities. P. aeruginosa concentrations in sewage and polluted natural waters were generally 3-4 log lower than the TC densities and 2 log lower than FC and FS concentrations. TC, FC and FS could be considered adequate indicators of the presence and densities of P. aeruginosa in natural waters, especially TC in freshwaters and FS in seawater respectively, as these parameters showed the best correlations and the most parallel inactivation processes with P. aeruginosa in each environment.

Near-infrared spectroscopy as a potential method for routine sediment analysis to improve rapidity and efficiency

1998 ◽  
Vol 37 (6-7) ◽  
pp. 181-188 ◽  
Author(s):  
Diane F. Malley
Keyword(s):  
Near Infrared ◽  
Organic Matter Content ◽  
Aggregate Size ◽  
Clay Content ◽  
Analytical Techniques ◽  
Matter Content ◽  
Near Infrared Reflectance ◽  
Organic C ◽  
Analytical Technique ◽  
Sediment Analysis

The potential for improvement in the rapidity, cost-effectiveness, and efficiency of sediment analysis by the application of near-infrared reflectance spectroscopy (NIRS) is recognized. The rapid (<2 min), non-chemical, non-destructive analytical technique of near-infrared (700–2500 nm) spectroscopy combines applied spectroscopy and complex statistics. It has been used for the experimental analysis of various constituents and functions of soils since the 1960s, and applications for the analysis of sediments are currently being explored. For application of NIRS, sediment samples require little preparation, other than drying, and the samples are not subject to the manipulations of conventional analytical techniques. The spectral information recorded in a 2 min scan can be used to predict numerous constituents and parameters on the samples once appropriate calibration equations have been prepared from sets of samples analyzed by both NIRS and conventional analytical techniques. Constituents and properties of soil and/or sediment analyzed by NIRS technology include moisture, organic matter content, organic C, CO3=, N, P, S, K, Ca, Mg, clay content, humic acids, lignin, cellulose, metal oxides, heavy metals, aggregate size, and inferred past pH of lakes. Several areas are identified where further research is needed to prepare for the application of NIRS to the routine analysis of sediments.

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