Laboratory Analysis Of Samples Research Articles

Carbon sequestration and the enzymic latch mechanism in red, black and white mangrove soils of Florida USA

Mangrove swamps are important habitat types providing vital ecological services, such as protection of coastlines from erosion and extreme weather conditions including hurricanes, recycling of nutrients and sequestration of carbon. Mangrove swamps support a wide range of biodiversity, improve water quality, provide fish for local communities. They are also used as a source of wood fuel, medication as well as for harvesting honey for the local population. Soil samples for laboratory analyses were collected from red (Rhizophora mangle), black (Avicennia germinans) and white (Laguncularia racemose) mangroves in Florida, USA to determine the biogeochemistry processes. Results of analyses indicated that the red mangrove soil is the most efficient for carbon sequestration. It had the lowest phenol oxidase activity (206.15 nmol dicq g-1 h-1), highest phenolic concentration (262.33 µg g-1) and lowest hydrolase enzyme activity (β-glucosidase) (3.04 nmol g-1 min-1) and, as a result, the highest concentration of soil organic matter (SOM) (57.9%). It is believed that the high soil water content (84.2%).) of the red mangrove, due to its proximity to the sea, is a key driver of these observations. The 'enzymic latch' mechanism appears to be prevalent in the red mangrove soil, in particular, allowing these ecosystems to be effective at carbon storage hence, could serve as an important natural tool in mitigating the effect of climate change. Preservation and conservation of mangrove swamps is vital in balancing the effect of global warming.

Effectiveness and cost of an incentive-based intervention on food safety and income in \u201cdibiteries\u201d in Dakar, Senegal

BackgroundRapid urbanisation in Sub-Saharan African cities such as Dakar, Senegal, leads to proliferation of informal braised meat restaurants known as “dibiteries”. Dibiteries do not often comply with minimal hygiene and food safety standards. The primary objective of this study was to assess the effectiveness and cost of a good hygiene practice intervention, identify factors that incentivize hygiene improvement and how that impacts on dibiteries’ income.MethodsA randomized controlled trial was carried out in Dakar dibiteries. The 120 random samples of braised meat were collected in three phases: (i) one-month pre-intervention, (ii) 2 months post-intervention, (iii) 10 months post-intervention. The trial comprised four groups of 10 dibiteries each: (a) (control) received no intervention, (b) a standardized training module, (c) a hygiene kit, (d) a training module and hygiene kit. Laboratory analysis of samples determined the total aerobic mesophilic flora (TAMF), thermotolerant coliforms (TC) and Staphylococcus aureus (SA). A questionnaire-based survey and focus group discussion were used to identify pre-intervention hygiene practices, and socioeconomic determinants of hygiene management in dibiteries post-intervention, respectively.ResultsSamples were found to be contaminated with TAMF, TC and SA. In phase 1, 27 and 13% of the samples contained TC and SA, respectively. In phase 2, no significant improvement of contamination rates was seen. In phase 3, microbiological quality of samples was significantly improved, with only 11.5% showing contamination with any of the bacterial species analysed (p < 0.1). Compared to the control group, only samples from dibiteries in group (b) had significantly reduced bacterial load in phase 3. The cost of intervention and hygiene improvement was estimated at 67 FCFA ($ 0.12) and 41 FCFA ($ 0.07) / day respectively and did not significantly impact on dibiterie profitability. Incentives to sustainably implement good hygiene practices were mainly linked to access to secure long-term workspaces.ConclusionThis intervention may have worked, but globally the results are mixed and not quite significant. However, continuous training in good hygiene practice and access to secure and sustainable infrastructure for dibiterie restaurants are the incentives necessary to achieve sustainable investments and behavioural change. We recommend further intervention refinement and testing other factors for promoting the adoption of good hygiene practices in the dibiteries in relation to consumers health risk.

Quantitative mapping of dolomitization using close-range hyperspectral imaging: Kimmeridgian carbonate ramp, Alacón, NE Spain

Abstract Geological models from outcrop analogues are often utilized as a guide, or soft constraint, for distributing reservoir properties in subsurface models. In carbonate outcrops, combined sequence stratigraphic, sedimentological, and petrographic studies constrain the heterogeneity of geobodies and diagenetic processes, including dolomitization, at multiple scales. High-resolution digital outcrop modeling further aids geometric mapping, geobody definition, and statistical analysis, though its usefulness for detailed mineralogical and lithological mapping is limited. Hyperspectral imaging offers enhanced spectral resolution for mapping subtle mineralogical differences. In both outcrops and subsurface, differences in carbonate composition can provide key information for distributing porosity and permeability, yet this mapping is highly challenging in field studies due to access difficulties, visible material differences, and sampling resolution. Spectral analysis of limestone–dolomite ratios conducted in laboratory studies indicates theoretical measures for quantitative identification and mapping of dolomite degrees within carbonate rocks. In this study, close-range hyperspectral imaging is applied to outcrops of the Alacón Member, Barranco del Mortero, northeastern Spain, to identify exposed limestone–dolomite geobodies and to quantify the degree of dolomitization across outcrop faces. Hyperspectral imaging is supplemented with photogrammetric outcrop modeling, field spectroscopy, and laboratory sample analysis for empirical validation and uncertainty analysis. Hyperspectral mapping shows that earlier fieldwork utilizing visual inspection of difficult to access outcrop surfaces had overestimated the amount of dolomite in the outcrop. Results indicate that hyperspectral imaging identified dolomite bodies more accurately and reliably than conventional field methods and facilitates the mapping of dolomite contribution in areas modified by dedolomitization, where dolomite content changes by more than ~20%.

Identification of the dynamics of carbon accumulation in the Verkh-Invenskoe peatland by the method of Loss on Ignition

Abstract. The Perm Kama region is characterized by numerous promising paleoar chives, and the paleoecological knowledge of the region is uneven. Identification of the dynamics of organic carbon accumulation in peat is included in the complex of studies used to reconstruct the state of the natural environment in the past. We have studied peat deposits of the Verkh-Invenskoe bog in the western part of the region. For this, depth measurements, sampling of a peat column, and laboratory analysis of samples throughout the thickness were performed. As a result, indicators were determined: Bulk Density (further BD), Organic Matter Bulk Density (further OMBD), Loss on Ignition (further LOI), Long term average rate of carbon accumulation (LORCA). For the first time for the western part of the Perm Kama region, numerical data on the dynamics of carbon accumulation over the last 10.9 thousand years have been obtained.

Development of validation methods to determine cadmium in cocoa almond from the beans by ICP-MS and ICP-OES

There are many publications on the quantification of cadmium (Cd) in cocoa beans and cocoa products. However, quantifying Cd in cocoa almonds from beans involves a critical step in the sample preparation process, such as dehulling the beans. This process is essential since it can affect the quality of the results if it is not carried out correctly because it has been reported that the testa presents cadmium concentrations between 3 and 4 times compared to almond. Therefore, this is the first study to validate two analytical methods for reliable Cd quantification in cocoa beans using inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) after microwave-assisted digestion that shows the proper pretreatment of cocoa beans to obtain accurate results from the analyzed samples. The Cd quantification limits using ICP-MS and ICP-OES were 0.005 mg kg−1 and 0.043 mg kg−1, respectively. The Cd recovery percentages with certified reference material (baking chocolate NIST® SRM® 2384) for ICP-MS and ICP-OES were 95% and 92%, respectively. The combined standard uncertainties obtained to determine Cd utilizing ICP-MS and ICP-OES did not exceed 8%. The laboratory's sample analysis of internal reference materials (IRM 1 and IRM 5) allowed quantifying Cd with values ​​lower and higher than the minimum amount allowed by the European regulation for cocoa-derived products (0.1 mg kg−1 of Cd).

A complete check-up of European eel after eight years of restocking in an upland river: Trends in growth, lipid content, sex ratio and health status

By combining field research and careful laboratory analysis of samples over the course of an eight-year study, we met the challenge of assessing the life history traits and health status of eels restocked in freshwater ecosystems. We found that restocked eels exhibited good growth performance; moreover, the stocks were female-dominated, showed a good Fulton's condition factor (K) and lipid stores and had high survival probability estimated using the best model of Jolly-Seber stock assessment method for open populations. A necropsy revealed the absence of internal lesions. A swim bladder examination revealed the absence of the parasite Anguillicola crassus. Polymerase chain reaction (PCR) analyses revealed an increase of Anguillid herpesvirus-1 (AngHV-1) prevalence throughout the study. Most positive subjects expressed viral loads compatible with a latent infection and correlated positively with K. All restocked eels were contaminated by at least one of the organic pollutant congeners studied, but the pollution loads corresponded to the lowest range of pollutant concentrations reported in the available literature for European eels and did not exceed the maximum residue and contaminant limits in food and feed of several national and international regulations. Pollutant loads were negatively correlated with K, lipid content and eel density for polychlorinated biphenyls PCB 138, 153 and 180 and K for pesticides p.p’-DDE, p.p’-DDD, p.p’-DDT and PBDE47. This study highlights the potential role played by upland aquatic ecosystems in enhancing riverine silver eel production from the perspective of species conservation. To be successful, restocking must be accompanied by improved ecosystem quality and migration routes for eels in inland freshwaters. We also provide some recommendations for future research to improve the management of restocking programmes.

PSIV-B-20 A fecal arsenic excretion pattern in pigs fed arsenic-containing rice bran

Abstract Rice bran is a common feed/food stuff for animals and humans; however, it usually contains a substantial amount of arsenic that is a class-I, non-threshold carcinogen to humans. This study was to investigate the fecal arsenic excretion pattern from the pigs fed an arsenic-containing rice bran. Twenty growing gilts (26.3 kg) were randomly assigned to 3 dietary treatments (n = 6 or 7) with Diets I, II, and III containing 0, 36.7, and 73.5% rice bran, and 0, 306, and 612 ppb arsenic, respectively. The feeding trial lasted 6 weeks, and fresh fecal samples were collected on Days 0, 14, 28, and 42 post-treatments. Fecal arsenic concentrations were analyzed using an ICP-MS protocol standardized by the U.S. Environmental Protection Agency. Tobit statistical model was employed for data analysis because some censored values were obtained from the laboratory sample analysis. Results (Table 1) showed that there were no differences in fecal arsenic concentrations from Day 0 through 42 post-treatment in pigs fed Diet I (a control diet). Nevertheless, the fecal arsenic concentration was increased significantly (P &amp;lt; 0.05) on Days 14 and 28 when compared to Day 0 post-treatment with Diet II (a moderate level of rice bran inclusion), and it was further increased (P &amp;lt; 0.05) on Day 42 post-treatment. The fecal arsenic excretion pattern in pigs fed Diet III (a high level of rice bran inclusion) was the same as that in pigs fed Diet II. The dietary treatment effects on fecal arsenic excretion were already reported previously. In short, the results of this study suggest that the fecal arsenic excretion is increased in the first 4 weeks and then further increased around the 6th week since the start of feeding arsenic-containing rice bran. This further increase may be due to the saturation of arsenic retention in pig body.

Distribution of 137Cs and 40K in the tissue of silver fir trees (Abies alba Mill.) from Lika (Croatia)

The research on activities of &lt;sup&gt;137&lt;/sup&gt;Cs and &lt;sup&gt;40&lt;/sup&gt;K, which was conducted on the silver fir (Abies alba Mill.) from Lika has included sampling of the trees in the field (rings of the bole from three different heights separated into bark, growth rings, roots, needles, shoots, and the soil surrounding the cut down trees), laboratory analysis of samples using the gamma-ray spectrometry and the statistical analysis of the collected data. The radial and vertical distribution of cesium (&lt;sup&gt;137&lt;/sup&gt;Cs) in trees was investigated. &lt;sup&gt;137&lt;/sup&gt;Cs has contaminated forest ecosystems by remote atmospheric transport and radioactive precipitation as a result of nuclear test including the nuclear accident in Chernobyl. On a longer time scale, the variability of the &lt;sup&gt;137&lt;/sup&gt;Cs distribution determined in the organisms of the silver fir depended on the half-life, while the seasonal dynamics were influenced by the degree of physiological activity and the characteristics and functions of plant tissues. The highest activity of &lt;sup&gt;137&lt;/sup&gt;Cs was determined in the bark and the physiologically most active parts of the silver fir (shoots and needles). The highest activity concentration of the &lt;sup&gt;137&lt;/sup&gt;Cs in the growth rings was measured in the lowest parts of the silver fir trees. This research contributed to understanding the behavior of &lt;sup&gt;137&lt;/sup&gt;Cs, which entered the organisms of dominant tree species in the forest ecosystem, as well as its distribution in time and space.

Recommendations for specimen collection for detection and diagnosis of COVID-19

Introduction: The spread of SARS-CoV-2 has caused a global public health crisis (pandemic). One of the most important measures to control the transmission chain of the new coronavirus is to identify those infected through laboratory testing. Objective: Synthesize the recommendations for the specimen collection for detection and diagnosis of COVID-19. Methods: This is an integrative review, considering the publications of the following databases: PubMed and Google Academic from January 2020. Results: 468 publications were identified, 20 of which were considered eligible. The publications recommend that technical training for specimen collection and careful observation of infection prevention protocols are fundamental. This manuscript highlights the steps for specimen collection as materials for collection, storage, transportation, individual protection, and laboratory analysis of samples. Currently, the Reverse Transcription - Polymerase Chain Reaction test is the recommended and gold standard method of identifying COVID-19 cases. Serological tests play an important role in research and surveillance. Conclusion: In summary, the documents ensure that the RT-PCR is the gold standard for SARS-CoV-2 detection and recommend standardization of collection and conditioning methods to avoid errors related to the collection and false negative results.

Contamination of Surface Waters of the Viluy River Basin by Mining Waste

In a number of heavy metals is very necessary for the sustenance of man and other living organisms, the so-called biogenic elements, there are also other causing the opposite effect, getting in a living organism, they lead to poisoning or death. These metals belong to the class of xenobiotics, that is, alien to life. Among the toxicant metals, a priority group was identified – Cd-cadmium, Cu-copper, As-arsenic, Ni-Nickel, Hg-mercury, Pb-lead, Zn-zinc, Cr-chromium and Fe-iron as the most dangerous to human and animal health. Of these, mercury, lead, and cadmium are the most toxic. The paper discusses pollution of surface waters of the rivers Irelyakh, Malaya Botuobiya and basin suspended solids-suspended solids, Fe-iron, Cu-copper, Zn-zinc Mn-manganese on the field “Irelyakhskoe placer” mining plant “Mirnyi” joint stock company “ALROSA”. The results of laboratory analyses of samples are presented, as well as the causes of contamination of river waters with these substances.

Correlation between left ventricular diastolic dysfunction and dyslipidaemia in asymptomatic patients with new-onset type 2 diabetes mellitus

BackgroundPoor glycaemic control is associated with a greater risk of development of heart failure in diabetic patients. We aimed to study the prevalence of left ventricular (LV) systolic and diastolic dysfunction in asymptomatic patients with new-onset type 2 DM. We conducted a cross-sectional study including patients with newly diagnosed (within 1 year) type 2 DM; all patients were between the ages of 30 and 60 years, normotensive and clinically asymptomatic and attended the outpatient clinic of the endocrinology unit at a university hospital between March 2016 and June 2017. Demographic characteristics, clinical risk factors and waist-hip ratio (WHR) were assessed. Blood samples for laboratory analysis were obtained. Detailed echocardiography was performed to evaluate systolic and diastolic function.ResultsA total of 100 patients were included. Sixty-one percent had diastolic dysfunction with preserved ejection fraction. Left ventricular diastolic dysfunction (LVDD) was more prevalent in diabetic patients with HbA1c ≥ 8.1 (75%) Patients with LVDD had significant dyslipidaemia in comparison to those without LVDD. Multivariate logistic regression analysis showed that WHR and HbA1c levels are the only predictors of impaired diastolic function in patients with new-onset DM. Kaplan-Meier survival curves showed a significant correlation between the incidence of diastolic dysfunction and the duration of DM, with higher incidence with HbA1c ≥ 8.1.ConclusionsDiastolic dysfunction is highly prevalent in patients with newly diagnosed DM and is positively correlated with HbA1c level, obesity, dyslipidaemia and the duration of diabetes.

A Roman Marble Cargo from a Shipwreck at Porto Cervo, Sassari, Sardinia, Italy

Results of laboratory analyses of samples of marble blocks found in a shipwrecked cargo at Porto Cervo demonstrate that they were almost certainly from the Apuan Alps, which implies that the ship c...

Development And Symbiosis of a Chlorella Strain in Natural and Extreme Conditions of The Aquatic Environment

The article studies the influence of natural and extreme conditions of the aquatic environment on the development and symbiosis of a strain of the unicellular planktonic green microalgae Chlorella vulgaris BIN, 6-10 microns in size. The studies were carried out in 2019, 2020 on the basis of laboratory analysis of samples taken at a depth of 10 cm from 15 control points of the Nizhny Fermsky pond of the Federal State Budgetary Educational Institution of Higher Education RSAU-Moscow Agricultural Academy named after K.A. Timiryazev, and in an open aquarium (bioreactor) with a volume of 50 liters in which, using the Arduino hardware and software complex, the temperature and lighting optimal for the growth of microalgae of the Chlorella vulgaris BIN strain were automatically maintained, as well as biochemical and physical conditions for the growth and development of microalgae were simulated strain Chlorella vulgaris BIN. In a separate study, completed in January 2020, the development and symbiosis of chlorella with unicellular and multicellular aquatic organisms was studied in an open aquarium with artificial lighting and temperature maintenance, in the presence of a critically large amount of macro and microelements used by the microalga of the Chlorella vulgaris BIN strain at the growth and reproduction. To calculate the number of chlorella cells in the samples, a Goryaev two-grid camera was used, in which the identification and quantitative accounting of chlorella cells was carried out according to the results of photographs and video filming, with the resolution settings of the Bresser LCD MICRO 5MP digital microscope at 125, 500 times, and at 1000 times electronic ZOOM magnification. As a result of the work carried out, a number of limiting factors have been identified that affect the growth and development of microalgae of the Chlorella vulgaris BIN strain and associations of microorganisms that coexist in symbiosis with microalgae.

Features of the morphological structure of plants and biochemical properties of introduced and domestic varieties of Cannabis sativa L.

Purpose. Identifying the features of the seasonal growth rhythm, development of the plants, morphological and biological differences in monoecious introduced and domestic varieties of Cannabis sativa L. in the North-east region of Ukraine.Methods. The research was conducted from 2014 till 2019. The following research methods were employed: field (phenological observations, sampling for laboratory analysis), microscopic (study of the morphological structure of glandular and cystolithic hairs on vegetative and generative organs, determination of the size and density of hair formation), laboratory and analytical (determination of the content of cannabinoid substances by thin layer and gas-liquid chromatography), biomorphological me­thods (analysis of morphological characteristics of plants). Chemical analysis for the content of cannabinoid substan­ces was carried out in the laboratory of the breeding and seed production department of the Institute of Bast Crops of the NAAS of Ukraine (Glukhiv, 2014–2019). The content of neutral substances [cannabinol (CBN), cannabidiol (CBD), tetrahydrocannabinol (THC)] and acids (CBDA, THCA) was determined by using a thin layer chromatography (TLC) and gas-liquid chromatography (GLC) methods. For the study, 11 monoecious varieties of C. sativa: ‘YuSO 1’, ‘YuSO 31’, ‘Hliana’, ‘Viktoriia’, ‘Hlesiia’, ‘Hlukhivskyi 46’, ‘Hlukhivski 51’, ‘Zoloto­niski 15’ and 3 introduced varieties: ‘Fedora 17’, ‘Felina 32’, ‘Futura 77’ (France) which differed among themselves in morphological, biological, genetic, ecological-geographical and economically valuable characteristics were selected.Results. Biological and morphological characteristics of modern monoecious varieties of C. sativa were investigated depending on the ecological and geographical zones of origin, conditions of the growing season and the stage of ontogenesis. The functional interdependence between the formation of specialized excretory structures and the content of cannabinoid substances in plants of different varieties of C. sa­tiva was revealed. The following promising varieties of C. sativa in a ration of ((THC + CBN) ≤ CBD) point the possibility to use them as the source material for creating the medicinal varie­ties of plants with a high content of CBD.Conclusions. Nowadays C. sativa is the main source of phyto material for industrial production of natural CBD. In recent years, high-yielding varieties of C. sativa have been created, which, together with high commercially valuable traits, did not contain psychoactive THC and had an insignificant amount of CBD. The results of the research indicated the features of the seasonal growth rhythm, development of the plants and the morphological and biological features of modern monoecious introduced and domestic varieties of C. sativa in the North-east region of Ukraine. The low correlation between the content of cannabinoid substances and their acids in varieties, which are cha­racterized by the low content of cannabinoid compounds was established. According to the developed own classification (THC + KBN): CBD, varieties with a predominant CBD content ‘Hlukhivskyi 46’, ‘Zolotoniski 15’, ‘Hliana’ which are of significant medicinal value were identified.

Development of novel technological approaches for a reliable crop characterization under changing environmental conditions

The expansion of world population requires the development of new strategies and tools for agriculture. Extensive breeding and agronomic efforts over the past 50 years have been responsible for tripling cereal yields, while advances in grain quality have been less evident. Continuing advances in the techniques available to breeders offer the potential to increase the rate of genetic improvement aiming to develop resilient crop and better (more resource use efficient) varieties. Plant breeders want to be able to phenotype large numbers of lines rapidly and accurately identify the best progeny. For this purpose, different methodological approaches have been proposed to evaluate these traits in the field: (1) proximal (remote) sensing and imaging, (2) laboratory analyses of samples, and (3) lab-based near-infrared reflectance spectroscopy analysis in the harvestable part of the crop. However, near-infrared reflectance spectroscopy-based field evaluation of yield and grain quality is currently a real option. Thus the development of new technological approaches, such as the use of hyperspectral imaging sensors or near-infrared reflectance spectroscopy under field conditions may be critical as a phenotypic approach for efficient breeding as well as in field management of crops. This article reports the description of the CropYQualT-CEC project funded by the H2020-MSCA-RISE program. This project pursues the main objective of generating a common solid knowledge basis within the context of precision agriculture and digital farming. Further, within the project context, the article also provides a case study in which prediction models for total grain protein content, based on the reflectance spectrum of wheat canopies, are presented. Measurements were performed at around anthesis, using a full range near-infrared reflectance spectroscopy field spectrometer. Several models explaining &gt;60% of grain protein variance in field trials illustrate the predictive capacity and robustness of this methodology for inferring grain quality traits well in advance of harvest.

KANDUNGAN FRAKSI SERAT RUMPUT ALAM PADA KETINGGIAN LOKASI YANG BERBEDA DI KABUPATEN TIMOR TENGAH SELATAN

This study aims at determining the content of natural grass fiber fraction at different altitudes. The method used was a survey method and each location had 10 plots by making random plots in taking the samples for laboratory analysis and descriptive analysis. The parameter measured was the fiber fraction. The results showed that the highest content of NDF fiber fraction was in Noebeba District while the highest content of ADF, Cellulose and Lignin was in South Amanuban District, while the lowest content of NDF, ADF, Cellulose, lignin was in North Mollo District and the lowest hemicellulose content was in South Amanuban District.

319 Application and Practices of RNA Sequencing for Understanding Transcriptional Regulation of Gene Expression by Dietary Nutrients or Feed Additives in Swine

Abstract In life science, RNA sequencing (RNA-seq) technique is a state-of-the-art research approach for tissue or cell transcriptome analyses. In recent years, RNA-seq has been applied to profile the gene expression in response to dietary nutrients or feed additives to gain thorough understanding of the complex nutrient-gene interactions in agricultural animals. In this presentation, we will selectively review the application of RNA-seq technique in nutrigenomics studies in swine. Such studies have investigated the impact of various sources and quantities of dietary fatty acids, protein (including alternative protein), energy, probiotics, and plant-derived bioactive compounds on the gene expression in major metabolic tissues, such as liver, muscle, and adipose. Although the RNA-seq methodology is a powerful quantitative tool for transcriptomics analysis, it still has various technical challenges and pitfalls throughout its practice steps that include experiment design, sample collection, sample laboratory analysis, data statistical and bioinformatic analyses, and data interpretation. Currently, many options are available for use in some steps, but a thorough understanding of each option is critical for making right decisions and avoiding getting into inconclusive results. Therefore, this presentation will also provide an overview on the “best practices” for applying RNA-seq technique in swine nutrigenomics studies, which include the aspects of appropriately designing experiments, collecting samples, and analyzing the data in order to have confidence in the results obtained from this approach. In short, the aims of this presentation are to provide some basic guidelines for researchers new in the field and to promote a discussion of standardization or “best practices” of RNA-seq methodology for animal nutrigenomics studies.

Constraints on the Mineralogy and Geochemistry of Vera Rubin Ridge, Gale Crater, Mars, From Mars Science Laboratory Sample Analysis at Mars Evolved Gas Analyses

AbstractVera Rubin ridge (VRR) is a topographic high within the layers of Mount Sharp, Gale crater, that exhibits a strong hematite spectral signature from orbit. The Mars Science Laboratory Curiosity rover carried out a comprehensive investigation to understand the depositional and diagenetic processes recorded in the rocks of VRR. Sample Analysis at Mars (SAM) evolved gas analyses (EGA) were performed on three samples from the ridge and one from directly beneath the ridge. SAM evolved H2O data suggested the presence of an Fe‐rich dioctahedral smectite, such as nontronite, in the sample from beneath the ridge. H2O data are also consistent with ferripyrophyllite in VRR samples. SAM SO2 data indicated that all samples contained Mg sulfates and some Fe sulfate. Several volatile detections suggested trace reduced sulfur sources, such as Fe sulfides and/or S‐bearing organic compounds, in two samples while significant O2 and NO evolved from one sample indicated the presence of oxychlorine and nitrate/nitrite salts, respectively. The O2 evolution was the second highest to date and the first observed in ~1,200 sols. HCl released from all samples likely resulted, in part, from trace chloride salts. All samples evolved CO2 and CO consistent with oxidized carbon compounds (e.g., oxalates), while some CO2 may result from carbonate. SAM‐derived constraints on the mineralogy and chemistry of VRR materials, in the context of additional mineralogy, geochemistry, and sedimentology information obtained by Curiosity, support a complex diagenetic history that involved fluids of a range of possible salinities, redox characteristics, pHs, and temperatures.

Rapid redox sensing of p-nitrotoluene in real water samples using silver nanoparticles

In the present work, a robust silver nanoparticle-based electrochemical sensor for the sensing of p-nitrotoluene (p-NT) has been described. The silver nanoparticles were synthesized using sonochemical technique and their purity, morphology and stability were established by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray, X-ray powder diffraction and thermogravimetric analysis; SEM and EDX analysis revealed an interesting structure of AgNPs containing p-NT, different from the usual AgNPs. The synthesized AgNPs were embedded over Au electrode for electrochemical-based efficient sensing of p-nitrotoluene (p-NT) in real water and laboratory sample. The mechanism of the 4-NT reduction reaction was examined using cyclic voltammetry (CV) while the electrochemical sensing of 4-NT was carried out using chronoamperometry; measurement of reduction peak current was observed with a regression coefficient of 0.987 which increased further upon enhancing the concentration of p-NT. The sensor also exhibited a linear response for the reduction of 4-nitrotoluene in the range of 0.01–0.10 µM with high sensitivity of 6.36 µA/µM cm2, and a very low limit of detection 0.092 µM. Overall, the results showed that the proposed AgNPs/Au electrode presents an efficient option for detecting the lowest concentration of p-NT wherein the sensor displays robust sensing platform with good reproducibility, stability, and selectivity toward the analytes in real as well as laboratory sample analysis.

Assessment of groundwater potential and quality using geophysical and physicochemical methods in the basement terrain of Southwestern, Nigeria

An integrated approach involving geophysical and physicochemical methods was undertaken to assess the potential availability of groundwater and its quality was carried out at Akole, Abeokuta Southwestern Nigeria. A combination of electrical resistivity and natural electric field methods were used in delineating the sub-surface lithology, determining potential groundwater-bearing zones, and the potential availability of groundwater for a community water supply. Laboratory analyses of samples from existing wells in the area was also carried out to determine the groundwater quality index (GWQI). Four vertical electrical sounding (VES) stations and nine profiles were surveyed using the Omega Campus and PQWT 150 instruments, respectively. The VES results delineated a maximum of five geo-electric sub-surface layers. A sudden change in the stratigraphy view of the rock formation from soft to very hard formation was observed in profile map L2. Profile map L7 and VES 2 has the highest potential for future groundwater exploration. Areas under VES 3 and profile maps L2, L3, L4, L5, L6, L8 and L9 are categorized as having a “medium” groundwater potential while the low yield water potential are areas under VES 1 and 4 and, profiles maps L1 and L10. The majority of groundwater in the weathered/fractured aquifer of the study area is slightly acidic. The GWQI values were less than 100, an indication that the analysed water samples fall within the “excellent” and “good” quality categories, implying that the groundwater is fit for domestic purposes. A combination of geophysical and physicochemical techniques has been successfully used to provide useful information for the assessment of groundwater potential and quality of the community.