The technical feasibility, mechanisms, and performance of degradation of aqueous imidacloprid have been studied at pilot scale in two well-defined photocatalytic systems of special interest because ...natural UV light can be used: heterogeneous photocatalysis with titanium dioxide and homogeneous photocatalysis by photo-Fenton. Equivalent pilot-scale and field conditions used for both allowed adequate comparison of the degree of mineralization and toxicity achieved as well as the transformation products generated in route to mineralization by both systems. Ninety-five percent of mineralization (<2.0 mg/L) was reached after 250 min of photocatalytic treatment with Fenton and 450 min with TiO2, meaning that TOC disappears 2.4 times faster with photo-Fenton photocatalytic treatment than with TiO2. The Daphnia Magna test for final residual TOC does not reveal any toxic behavior. Transformation products evaluated by GC-MS/AED after two SPE procedures and LC-IC were the same in both cases. The main differences between the two processes are in the amount of transformation products (TPs) generated, not in the TPs detected which were always the same. At the end of both processes low concentration (<0.1 mg/L) of 2 pyrrolidinone (transformation product) remains in the dissolution and around 1 mg/L of formate in the case of photo-Fenton.
Due to the basic properties of nicotine, it is not easily integrated into commonly used multiresidue methods. The present work investigates the application of two commonly employed multiresidue ...methods—the QuEChERS method and the ethyl acetate method—for determining nicotine in mushrooms. Both methods are employed in a modified form and an unmodified form: the former to address the special properties of nicotine and the latter, combined with the use of isotopically labelled nicotine, to compensate for poor recoveries. The QuEChERS-based methods were followed by liquid chromatography–time-of-flight mass spectrometry and those based on ethyl acetate extraction were followed by gas chromatography–triple quadrupole-mass spectrometry. All methods were validated according to European guidelines (document no. SANCO/10684/2009). Recovery studies performed on mushroom spiked at 10 and 100 μg kg
−1
yielded average recoveries in the range 80–110% with relative standard deviation (RSD) values below 9%. The linearity of the response over two orders of magnitude was demonstrated (
r
2
> 0.995) for all of the determination techniques employed. The limits of detection and quantification obtained were in the 0.7 and 10 μg kg
−1
range, depending on the technique, and thus below the maximum residue level established for this toxic alkaloid by current EU legislation. Good repeatability and reproducibility were obtained in terms of the RSD of the analytical methods (0.4–13.2%). The modified QuEChERS method was tested in a proficiency test on nicotine in dried mushrooms obtaining good results. The methods were successfully applied to 20 real samples.
The molecular characteristics of chlorothalonil can cause particular determination difficulties in some vegetable commodities such as leek or garlic. These difficulties are mainly related to the low ...recoveries obtained using common multi-residue methods (MRMs) - a consequence of the very high interaction level with natural components in the matrix. These shortcomings were pointed out in the last European Proficiency Test for Pesticide Residues on Fruits and Vegetables, where false negatives for chlorothalonil in leek were observed at around 50%. In this study we have evaluated the ethyl acetate, the Dutch mini-Luke and the QuEChERS MRMs to compare their capabilities for chlorothalonil determination using GC-MS/MS in both the electron impact ionization (EI) and negative chemical ionization (NCI) modes. Best recoveries (in the range of 100-120%, with an RSD below 20%) were obtained using the Dutch mini-Luke method. Lower values (52-70%) were obtained for ethyl acetate whereas no recovery was obtained when the QuEChERS method was applied. Furthermore, tomato matrix was also included in the experiments in order to facilitate the comparability of results. Two ionization modes, electron impact ionization (EI) and negative chemical ionization (NCI) in GC-MS/MS, were applied to evaluate their respective advantages and disadvantages for quantification and identification. As expected, NCI showed limits of detection (LODs) 5 to 10 times lower than EI. However, in both cases, the LODs were still below 10 μg kg
−1
. The proposed optimal method was applied for chlorothalonil determination in leek and garlic with good results - in accordance with the European Union (EU) Analytical Quality Control (AQC) Guidelines for pesticides analysis.
The molecular characteristics of chlorothalonil can cause particular determination difficulties in some vegetable commodities such as leek or garlic.
Abstract
Background
In patients with heart failure and reduced ejection fraction (HFrEF), treatment with sacubitril-valsartan (SAC/VAL) reduces N-terminal B-type natriuretic peptide (NT-proBNP) ...levels and appears to have a beneficial effect on ventricular remodelling (VR), although the mechanism of this effect has yet to be established. ST2 is a novel biomarker reflecting inflammation and haemodynamic stress, closely related to the pathophysiology of heart failure (HF), fibrosis and VR. Several studies have shown that elevated levels of ST2 are associated with increased risk of developing HF and worse prognosis, being an independent predictor of adverse clinical outcomes, and even establishing a correlation with clinical changes and NT-proBNP levels.
Purpose
To evaluate the effect of SAC/VAL treatment on left ventricular remodelling and fibrosis in patients with HFrEF by monitoring ST2 and NTproBNP levels during follow-up.
Methods
Prospective single-centre, open-label, single-group, prospective study including patients with HFrEF and NYHA functional class II–IV, under follow-up in our HF Unit from April 2018 to July 2020 with a 12-month follow-up for each patient. Biomarker measurements and echocardiography were performed at baseline, 6 and 12 months after initiation of SAC/VAL treatment. In addition, cardiac magnetic resonance imaging (CMRI) was performed at baseline and after 12 months of treatment.
Results
68 patients were included (mean age 65.63±11.78 years; 29.4% female). Baseline characteristics are shown in table 1. The mean baseline NT-proBNP and ST2s concentration was 2238.24±2148.65 pg/mL and 42.31±28.38 ng/mL respectively, with a statistically significant reduction after 12 months with SAC/VAL (NTproBNP 701.65±778.13 pg/mL and ST2 30.22±9.70 ng/mL; p<0.01 in both cases). In addition, there was an improvement in left ventricular ejection fraction (LVEF) on echocardiography from 31.01±5.65% at baseline to 45.03±9.45% at 12 months (p<0.01). We also observed a statistically significant reduction in left ventricular end-diastolic and end-systolic diameter at 12 months from baseline (60.86±4.99 mm and 57.35±5.36 mm, p<0.01; 40.70±3.76 mm and 37.23±4.37 mm, p<0.01). These data suggesting reverse remodelling were also confirmed with CMRI, finding improved LVEF (32.90±6.65% vs 46.22±11.1%, p<0.01) and reduced end-diastolic (192.06±60.63 and 160.73±49.68, p<0.01) and end-systolic (125.28±52.07 and 90.74±41.79, p<0.01) volumes. During follow-up there were no alterations in renal function (creatinine 0.98±0.28 mg/dL at baseline, 1.03±0.32 mg/dL at 12 months, p=0.04) or potassium levels (4.50±0.40 mEq/L at baseline, 4.76±0.38 mEq/L at 12 months, p=0.22).
Conclusion
SAC/VAL treatment is associated with a reduction in NT-proBNP and ST2 concentrations which seems to support its beneficial effect on ventricular remodelling, allowing its monitoring to assess the evolution and prognosis of HF patients.
Funding Acknowledgement
Type of funding sources: Other. Main funding source(s): Novartis
A gas chromatography–mass spectrometry method in negative chemical ionization mode has been developed incorporating simultaneous detection using a micro-electron capture detector (μ-ECD) for the ...determination of pesticides in fruits and vegetables. This instrument configuration uses a three-way splitter device which divides the effluent from the analytical column between the two detectors with the split ratio 1:0.1 (MSD/μ-ECD) in each run. The μ-ECD was used for confirmation purposes. Validation of the method was performed on three matrices: tomato, apple, and orange. The ethyl acetate method was assayed; recovery studies were performed at 10 and 100 μg/kg. Recoveries between 70% and 120% were achieved and relative standard deviations lower than 20% (
n
= 5) were obtained for all pesticides and matrices studied. Limits of quantification lower than 10 μg/kg were obtained for 100% of pesticides in all of the matrices. Limits of quantification lower than 2.5 μg/kg were achieved for 77.8% of pesticides in the tomato and apple matrices, and for 72.2% of pesticides in the orange matrix. The method showed linear response in the concentration range tested (2.5–500 μg/kg) with correlation coefficients >0.99. Good repeatability and reproducibility results were obtained in all cases, with relative standard deviations lower than 16.7% and 20%, respectively. Finally, 20 incurred samples were analyzed using the proposed method. The simultaneous use of the two detectors was satisfactory for the analysis of these real samples. The total number of pesticides identified was 25. The number of samples which contained at least one pesticide was 15—this represented 75% of the total number of samples studied.
The main objective of this work was to establish a mathematical function that correlates pesticide residue levels in apple juice with the levels of the pesticides applied on the raw fruit, taking ...into account some of their physicochemical properties such as water solubility, the octanol/water partition coefficient, the organic carbon partition coefficient, vapour pressure and density. A mixture of 12 pesticides was applied to an apple tree; apples were collected after 10 days of application. After harvest, apples were treated with a mixture of three post-harvest pesticides and the fruits were then processed in order to obtain apple juice following a routine industrial process. The pesticide residue levels in the apple samples were analysed using two multi-residue methods based on LC-MS/MS and GC-MS/MS. The concentration of pesticides was determined in samples derived from the different steps of processing. The processing factors (the coefficient between residue level in the processed commodity and the residue level in the commodity to be processed) obtained for the full juicing process were found to vary among the different pesticides studied. In order to investigate the relationships between the levels of pesticide residue found in apple juice samples and their physicochemical properties, principal component analysis (PCA) was performed using two sets of samples (one of them using experimental data obtained in this work and the other including the data taken from the literature). In both cases the correlation was found between processing factors of pesticides in the apple juice and the negative logarithms (base 10) of the water solubility, octanol/water partition coefficient and organic carbon partition coefficient. The linear correlation between these physicochemical properties and the processing factor were established using a multiple linear regression technique.
The Very Large Array Sky Survey (VLASS) is a synoptic, all-sky radio sky survey with a unique combination of high angular resolution ( 2 5), sensitivity (a 1 goal of 70 Jy/beam in the coadded data), ...full linear Stokes polarimetry, time domain coverage, and wide bandwidth (2-4 GHz). The first observations began in 2017 September, and observing for the survey will finish in 2024. VLASS will use approximately 5500 hr of time on the Karl G. Jansky Very Large Array (VLA) to cover the whole sky visible to the VLA (decl. > −40°), a total of 33 885 deg 2 . The data will be taken in three epochs to allow the discovery of variable and transient radio sources. The survey is designed to engage radio astronomy experts, multi-wavelength astronomers, and citizen scientists alike. By utilizing an "on the fly" interferometry mode, the observing overheads are much reduced compared to a conventional pointed survey. In this paper, we present the science case and observational strategy for the survey, and also results from early survey observations.
The obligation for accredited laboratories to participate in proficiency tests under ISO 17025, performing multiresidue methods (MRMs) for pesticide residues, involves the reporting of a large number ...of individual z scores making the evaluation of the overall performance of the laboratories difficult. It entails, time and again, the need for ways to summarise the laboratory's overall assessment into a unique combined index. In addition, the need for ways to continually evaluate the performance of the laboratory over the years is equally acknowledged. For these reasons, following 14 years of the European Union Reference Laboratory for Pesticide Residues in Fruits and Vegetables (EUPT-FV), useful formulas have been designed to globally evaluate the assessment of the participating laboratories. The aim is to achieve a formula which is easy to understand, which can be applied and which fits the purposes of long-term evaluation detecting positive and negative trends. Moreover, consideration is needed for a fair compensation of bad results in MRM, taking into account the large number of compounds that are covered. It is therefore important to be aware of the difficulties in getting satisfactory values from a wide range of compounds. This work presents an evaluation of the main well-established combined z score formulas together with those new ones developed here which have been applied to the European proficiency test results (EUPTs) over the years. Previous formulas such as the rescaled sum of z score (RSZ), the sum squared of z score (SSZ) and the relative laboratory performance (RLP) are compared with the newer ones: the sum of weighted z scores (SWZ) and the sum of squared z scores (SZ2). By means of formula comparisons, conclusions on the advantages, drawbacks and the most fit-for-purpose approach are achieved.
Abstract The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies ...and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond redshift z > 3.5, and employ redshift space distortions to measure the growth of structure and probe potential modifications to general relativity. We describe the significant instrumentation we developed to conduct the DESI survey. This includes: a wide-field, 3.°2 diameter prime-focus corrector; a focal plane system with 5020 fiber positioners on the 0.812 m diameter, aspheric focal surface; 10 continuous, high-efficiency fiber cable bundles that connect the focal plane to the spectrographs; and 10 identical spectrographs. Each spectrograph employs a pair of dichroics to split the light into three channels that together record the light from 360–980 nm with a spectral resolution that ranges from 2000–5000. We describe the science requirements, their connection to the technical requirements, the management of the project, and interfaces between subsystems. DESI was installed at the 4 m Mayall Telescope at Kitt Peak National Observatory and has achieved all of its performance goals. Some performance highlights include an rms positioner accuracy of better than 0.″1 and a median signal-to-noise ratio of 7 of the O ii doublet at 8 × 10 −17 erg s −1 cm −2 in 1000 s for galaxies at z = 1.4–1.6. We conclude with additional highlights from the on-sky validation and commissioning, key successes, and lessons learned.
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