scholarly journals Acute and Chronic Effects of a Glyphosate and a Cypermethrin-Based Pesticide on a Non-Target Species Eucypris sp. Vavra, 1891 (Crustacea, Ostracoda)

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 701
Author(s):  
Arsène Mathieu Houssou ◽  
Daniel Cocan ◽  
Camelia Maria Răducu ◽  
Eric Joslin Daguégué ◽  
Vioara Miresan ◽  
...  
Keyword(s):  
Population Growth ◽  
Chronic Exposure ◽  
High Sensitivity ◽  
Population Level ◽  
Control Treatment ◽  
Agricultural Pesticides ◽  
Low Concentrations ◽  
Glyphosate Herbicide ◽  
Parthenogenetic Reproduction ◽  
Acute And Chronic Effects

Ostracoda species are indicators of their current and past environment (paleoenvironment). The study aims to evaluate the acute and chronic sensitivities of a freshwater ostracod species (Eucypris sp.) to agricultural pesticides (a cypermethrin-based insecticide and a glyphosate herbicide-based formulation). Lethal concentrations (LC50) of each pesticide for the species at 24 and 48 h were determined. The chronic exposure allowed assessing the effects of low concentrations of both pesticides; firstly, on the parthenogenetic reproduction of Eucypris sp., and, secondly, on its population growth. Then, individuals of Eucypris sp. were exposed to 0.536 ppb and 1.072 ppb of cypermethrin and 4.51 ppm and 9.03 ppm of glyphosate. These concentrations are respectively the 10%, and the 20% of the 48-h LC50 (median lethal concentration) of both pesticides for the species. The estimated 24-h LC50 of cypermethrin was 7.287 ppb. At 48-h, it was 5.361 ppb. For glyphosate, the 24-h LC50 was 50.521 ppm, while at 48-h it was 45.149 ppm. After 10 days of exposure to low concentrations of cypermehrin, only 30% of females reproduced parthenogenetically with 10% and 20% of LC50-48-h. For the control treatment, reproduction in 80% of females was observed. Eucypris sp. population growth after 28 days of exposure to low concentrations of cypermethrin showed significant retardation. Regarding glyphosate chronic exposure, 60%, 50%, and 90% of individuals were able to reproduce at 10% of LC50-48-h, 20% LC50-48-h, and the control treatment, respectively. The population growth was also affected by the tested low concentrations of glyphosate. The study showed high sensitivity of Eucypris sp. to cypermethrin compared to glyphosate. However, low concentrations of both pesticides affected the species at individual and population level.

scholarly journals All-Dielectric Metasurface for Sensing Microcystin-LR

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1363
Author(s):  
Binze Ma ◽  
Ao Ouyang ◽  
Juechen Zhong ◽  
Pavel A. Belov ◽  
Ravindra Kumar Sinha ◽  
...  
Keyword(s):  
Quality Factor ◽  
Bound States ◽  
High Sensitivity ◽  
Concentration Limit ◽  
Specific Recognition ◽  
Low Concentrations ◽  
Freshwater Bodies ◽  
Toxic Pollutant ◽  
Small Change ◽  
Dielectric Metasurface

Sensing Microcystin-LR (MC-LR) is an important issue for environmental monitoring, as the MC-LR is a common toxic pollutant found in freshwater bodies. The demand for sensitive detection method of MC-LR at low concentrations can be addressed by metasurface-based sensors, which are feasible and highly efficient. Here, we demonstrate an all-dielectric metasurface for sensing MC-LR. Its working principle is based on quasi-bound states in the continuum mode (QBIC), and it manifests a high-quality factor and high sensitivity. The dielectric metasurface can detect a small change in the refractive index of the surrounding environment with a quality factor of ~170 and a sensitivity of ~788 nm/RIU. MC-LR can be specifically identified in mixed water with a concentration limit of as low as 0.002 μg/L by a specific recognition technique for combined antigen and antibody. Furthermore, the demonstrated detection of MC-LR can be extended to the identification and monitoring of other analytes, such as viruses, and the designed dielectric metasurface can serve as a monitor platform with high sensitivity and high specific recognition capability.

scholarly journals The Double Face of Ketamine—The Possibility of Its Identification in Blood and Beverages

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 813
Author(s):  
Magdalena Świądro ◽  
Paweł Stelmaszczyk ◽  
Irena Lenart ◽  
Renata Wietecha-Posłuszny
Keyword(s):  
Date Rape ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Heroin Addiction ◽  
Assisted Extraction ◽  
Low Concentrations ◽  
High Concentrations ◽  
Rosé Wine ◽  
Tof Ms

The purpose of this study was to develop and validate a high-sensitivity methodology for identifying one of the most used drugs—ketamine. Ketamine is used medicinally to treat depression, alcoholism, and heroin addiction. Moreover, ketamine is the main ingredient used in so-called “date-rape” pills (DRP). This study presents a novel methodology for the simultaneous determination of ketamine based on the Dried Blood Spot (DBS) method, in combination with capillary electrophoresis coupled with a mass spectrometer (CE-TOF-MS). Then, 6-mm circles were punched out from DBS collected on Whatman DMPK-C paper and extracted using microwave-assisted extraction (MAE). The assay was linear in the range of 25–300 ng/mL. Values of limits of detection (LOD = 6.0 ng/mL) and quantification (LOQ = 19.8 ng/mL) were determined based on the signal to noise ratio. Intra-day precision at each determined concentration level was in the range of 6.1–11.1%, and inter-day between 7.9–13.1%. The obtained precision was under 15.0% (for medium and high concentrations) and lower than 20.0% (for low concentrations), which are in accordance with acceptance criteria. Therefore, the DBS/MAE/CE-TOF-MS method was successfully checked for analysis of ketamine in matrices other than blood, i.e., rose wine and orange juice. Moreover, it is possible to identify ketamine in the presence of flunitrazepam, which is the other most popular ingredient used in DRP. Based on this information, the selectivity of the proposed methodology for identifying ketamine in the presence of other components of rape pills was checked.

Extrathyroidal Effects of Low Concentrations of Thiourea on Rainbow Trout, Salmo gairdneri

1981 ◽  
Vol 38 (10) ◽  
pp. 1283-1285 ◽  
Author(s):  
J. G. Eales
Keyword(s):  
Rainbow Trout ◽  
Chronic Exposure ◽  
Degradation Rate ◽  
Salmo Gairdneri ◽  
Low Concentrations ◽  
Direct Sensitivity ◽  
Distribution Spaces ◽  
Circulating Levels

Chronic exposure of fed immature rainbow trout (Salmo gairdneri) to a low ambient thiourea (TU) concentration did not depress circulating levels of T4 (thyroxine) or triiodothyronine, T4 degradation rate, or T4 deiodination rate indicating no significant T4 influence on thyroidal hormone output. However, TU increased the hematocrit and decreased distribution spaces for iodide and T4, indicating direct sensitivity of extrathyroidal processes to TU.Key words: thiourea, thyroxine, hematocrit, iodide metabolism, rainbow trout

Diagnostic tests for detecting Chlamydia trachomatis and Neisseria gonorrhoeae in rectal and pharyngeal specimens

2021 ◽  
Author(s):  
Paul C. Adamson ◽  
Jeffrey D. Klausner
Keyword(s):  
Chlamydia Trachomatis ◽  
Neisseria Gonorrhoeae ◽  
Bacterial Infections ◽  
Point Of Care ◽  
High Sensitivity ◽  
Population Level ◽  
The United States ◽  
Nucleic Acid Amplification ◽  
Point Of Care Test ◽  
Control And Prevention

Chlamydia trachomatis and Neisseria gonorrhoeae are two of the most often reported bacterial infections in the United States. The rectum and oropharynx are important anatomic sites of infection and can contribute to ongoing transmission. Nucleic acid amplification tests (NAATs) are the mainstays for the detection of C. trachomatis and N. gonorrhoeae infections owing to their high sensitivity and specificity. Several NAATs have been evaluated for testing in rectal and pharyngeal infections. A few assays recently received clearance by the Food and Drug Administration, including one point-of-care test. Those assays can be used for testing in symptomatic individuals, as well as for asymptomatic screening in certain patient populations. Routine screening for C. trachomatis in pharyngeal specimens is not recommended by the Centers for Disease Control and Prevention, though is often performed due to the use of multiplex assays. While expanding the types of settings for screening and using self-collected rectal and pharyngeal specimens can help to increase access and uptake of testing, additional research is needed to determine the potential benefits and costs associated with increased screening for rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections on a population level.

Low concentrations of hydrogen sulphide alter monoamine levels in the developing rat central nervous system

1992 ◽  
Vol 70 (11) ◽  
pp. 1515-1518 ◽  
Author(s):  
B. Skrajny ◽  
R. S. Hannah ◽  
S. H. Roth
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Frontal Cortex ◽  
Hydrogen Sulphide ◽  
Chronic Exposure ◽  
Brain Regions ◽  
Target Organs ◽  
Low Concentrations ◽  
The Central Nervous System ◽  
Developing Rat

The central nervous system is one of the primary target organs for hydrogen sulphide (H2S) toxicity; however, there are limited data on the neurotoxic effects of low-dose chronic exposure on the developing nervous system. Levels of serotonin and norepinephrine in the developing rat cerebellum and frontal cortex were determined following chronic exposure to 20 and 75 ppm H2S during perinatal development. Both monoamines were altered in rats exposed to 75 ppm H2S compared with controls; serotonin levels were significantly increased at days 14 and 21 postnatal in both brain regions, and norepinephrine levels were significantly increased at days 7, 14, and 21 postnatal in cerebellum and at day 21 in the frontal cortex. Exposure to 20 ppm H2S significantly increased the levels of serotonin in the frontal cortex at day 21, whereas levels of norepinephrine were significantly reduced in the frontal cortex at days 14 and 21, and at day 14 in the cerebellum.Key words: hydrogen sulphide, monoamines, serotonin, norepinephrine, neurotoxicity.

Egg white hydrolysate promotes neuroprotection for neuropathic disorders induced by chronic exposure to low concentrations of mercury

2016 ◽  
Vol 1646 ◽  
pp. 482-489 ◽  
Author(s):  
Danize Aparecida Rizzetti ◽  
Francisca Fernandez ◽  
Silvia Moreno ◽  
José Antonio Uranga Ocio ◽  
Franck Maciel Peçanha ◽  
...  
Keyword(s):  
Chronic Exposure ◽  
Egg White ◽  
Low Concentrations

Assessment of invasive rodent impacts on island avifauna: methods, limitations and the way forward

2015 ◽  
Vol 42 (2) ◽  
pp. 185 ◽  
Author(s):  
Lise Ruffino ◽  
Diane Zarzoso-Lacoste ◽  
Eric Vidal
Keyword(s):  
Population Growth ◽  
Population Level ◽  
Bird Conservation ◽  
Bird Population ◽  
Breeding Parameters ◽  
Population Growth Rates ◽  
Bird Populations ◽  
Field Evidence ◽  
Bird Breeding

Bird conservation is nowadays a strong driving force for prioritising rodent eradications, but robust quantitative estimates of impacts are needed to ensure cost-effectiveness of management operations. Here, we review the published literature to investigate on what methodological basis rodent effects on island bird communities have been evaluated for the past six decades. We then discuss the advantages and limitations of each category of methods for the detection and quantification of impacts, and end with some recommendations on how to strengthen current approaches and extend our knowledge on the mechanisms of impacts. Impact studies (152 studies considered) emphasised seabirds (67%), black rats (63%) and the Pacific Ocean (57%). Among the most commonly used methods to study rodent impacts on birds were the observation of dead eggs or empty nests while monitoring bird breeding success, and the analyses of rodent diets, which can both lead to misleading conclusions if the data are not supported by direct field evidence of rodent predation. Direct observations of rodent–bird interactions (19% of studies) are still poorly considered despite their potential to reveal cryptic behaviours and shed light on the mechanisms of impacts. Rodent effects on birds were most often measured as a change or difference in bird breeding parameters (74% of studies), while estimates of bird population growth rates (4%) are lacking. Based on the outcomes of this literature review, we highlight the need for collecting unbiased population-level estimates of rodent impacts, which are essential prerequisites for predicting bird population growth scenarios and prioritising their conservation needs. This could be achieved by a more systematic integration of long-term monitoring of bird populations into rodent management operations and modelling bird population dynamics. We also strongly recommend including various complementary methods in impact assessment strategies to unravel complex interactions between rodents and birds and avoid faulty evidence. Finally, more research should be devoted to a better understanding of the cases of non-impacts (i.e. long-term coexistence) and those impacts mediated by mechanisms other than predation and ecosystem-level processes.

scholarly journals Measuring Thiols in Single Cultivar South African Red Wines Using 4,4-Dithiodipyridine (DTDP) Derivatization and Ultraperformance Convergence Chromatography-Tandem Mass Spectrometry

Foods ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 138 ◽  
Author(s):  
Mpho Mafata ◽  
Maria Stander ◽  
Baptiste Thomachot ◽  
Astrid Buica
Keyword(s):  
South African ◽  
Red Wine ◽  
High Sensitivity ◽  
White Wine ◽  
Wine Aroma ◽  
Low Concentrations ◽  
Varietal Thiols ◽  
Cultivar Differentiation ◽  
First Time ◽  
Ionization Methods

Wine varietal thiols are important contributors to wine aroma. The chemical nature of thiols makes them difficult to measure due to low concentrations, high sensitivity to oxidation, and low ionization. Methods for the measurement of thiols usually consist of multiple steps of sample preparation followed by instrumental measurement. Studies have collected large datasets of thiols in white wine but not in red wine, due to the lack of availability of suitable methods. In this study, for the first time, convergence chromatography was used to measure thiols in red wine at ultratrace levels with improved sensitivity compared to previous methods. Performance parameters (selectivity, linearity, limits of detection, precision, accuracy) were tested to demonstrate the suitability of the method for the proposed application. Red wine thiols were measured in South African Pinotage, Shiraz, and Cabernet Sauvignon wines (n = 16 each). Cultivar differentiation using the thiol profile was demonstrated.

scholarly journals The shape of density dependence and the relationship between population growth, intraspecific competition and equilibrium population density

2018 ◽  
Author(s):  
Emanuel A. Fronhofer ◽  
Lynn Govaert ◽  
Mary I. O’Connor ◽  
Sebastian J. Schreiber ◽  
Florian Altermatt
Keyword(s):  
Population Growth ◽  
Growth Models ◽  
Population Level ◽  
Logistic Growth ◽  
Population Densities ◽  
Density Regulation ◽  
Logistic Growth Model ◽  
Regulation Functions ◽  
Consumer Resource ◽  
Population Growth Models

AbstractThe logistic growth model is one of the most frequently used formalizations of density dependence affecting population growth, persistence and evolution. Ecological and evolutionary theory and applications to understand population change over time often include this model. However, the assumptions and limitations of this popular model are often not well appreciated.Here, we briefly review past use of the logistic growth model and highlight limitations by deriving population growth models from underlying consumer-resource dynamics. We show that the logistic equation likely is not applicable to many biological systems. Rather, density-regulation functions are usually non-linear and may exhibit convex or both concave and convex curvatures depending on the biology of resources and consumers. In simple cases, the dynamics can be fully described by the continuous-time Beverton-Holt model. More complex consumer dynamics show similarities to a Maynard Smith-Slatkin model.Importantly, we show how population-level parameters, such as intrinsic rates of increase and equilibrium population densities are not independent, as often assumed. Rather, they are functions of the same underlying parameters. The commonly assumed positive relationship between equilibrium population density and competitive ability is typically invalid. As a solution, we propose simple and general relationships between intrinsic rates of increase and equilibrium population densities that capture the essence of different consumer-resource systems.Relating population level models to underlying mechanisms allows us to discuss applications to evolutionary outcomes and how these models depend on environmental conditions, like temperature via metabolic scaling. Finally, we use time-series from microbial food chains to fit population growth models and validate theoretical predictions.Our results show that density-regulation functions need to be chosen carefully as their shapes will depend on the study system’s biology. Importantly, we provide a mechanistic understanding of relationships between model parameters, which has implications for theory and for formulating biologically sound and empirically testable predictions.

scholarly journals Prognostic Performance of a High-Sensitivity Cardiac Troponin I Assay in Patients with Non–ST-Elevation Acute Coronary Syndrome

2014 ◽  
Vol 60 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Erin A Bohula May ◽  
Marc P Bonaca ◽  
Petr Jarolim ◽  
Elliott M Antman ◽  
Eugene Braunwald ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
High Sensitivity ◽  
Cardiovascular Death ◽  
Cardiac Troponin I ◽  
Fourth Generation ◽  
Prognostic Performance ◽  
Coronary Syndrome ◽  
Low Concentrations ◽  
Increased Risk

Abstract BACKGROUND High-sensitivity assays for cardiac troponin enable more precise measurement of very low concentrations and improved diagnostic accuracy. However, the prognostic value of these measurements, particularly at low concentrations, is less well defined. METHODS We evaluated the prognostic performance of a new high-sensitivity cardiac troponin I (hs-cTnI) assay (Abbott ARCHITECT) compared with the commercial fourth generation cTnT assay in 4695 patients with non–ST-segment elevation acute coronary syndromes (NSTE-ACS) from the EARLY-ACS (Early Glycoprotein IIb/IIIa Inhibition in NSTE-ACS) and SEPIA-ACS1-TIMI 42 (Otamixaban for the Treatment of Patients with NSTE-ACS) trials. The primary endpoint was cardiovascular death or new myocardial infarction (MI) at 30 days. Baseline cardiac troponin was categorized at the 99th percentile reference limit (26 ng/L for hs-cTnI; 10 ng/L for cTnT) and at sex-specific 99th percentiles for hs-cTnI. RESULTS All patients at baseline had detectable hs-cTnI compared with 94.5% with detectable cTnT. With adjustment for all other elements of the TIMI risk score, patients with hs-cTnI ≥99th percentile had a 3.7-fold higher adjusted risk of cardiovascular death or MI at 30 days relative to patients with hs-cTnI <99th percentile (9.7% vs 3.0%; odds ratio, 3.7; 95% CI, 2.3–5.7; P < 0.001). Similarly, when stratified by categories of hs-cTnI, very low concentrations demonstrated a graded association with cardiovascular death or MI (P-trend < 0.001). Use of sex-specific cutpoints did not improve prognostic performance. Patients with negative fourth generation cTnT (<10 ng/L) but hs-cTnI ≥26 ng/L were at increased risk of cardiovascular death/MI compared to those with hs-cTnI <26 ng/L (9.2% vs 2.9%, P = 0.002). CONCLUSIONS Application of this hs-cTnI assay identified a clinically relevant higher risk of recurrent events among patients with NSTE-ACS, even at very low troponin concentrations.

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