1,903 research outputs found

    Analytical study on ethephon residue determination in water by ion-pairing liquid chromatography/tandem mass spectrometry

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    A detailed analytical study on ethephon residue determination in water, making use of ion-pairing liquid chromatography coupled to electrospray tandem mass spectrometry (LC/MS/MS), has been carried out. Ethephon is a plant growth regulator, highly polar, which is typically present in aqueous solution in anionic form due to its acid character. Both its extraction and pre-concentration from water samples and its chromatographic retention are difficult. Several approaches for sample pretreatment have been tested including direct injection into the chromatographic system, on-line solid phase extraction (SPE) and off-line SPE, with the best results being obtained after off-line SPE, using Oasis MAX cartridges (mixed-mode strong anion-exchange). After testing several ion-pairing reagents, tetrabuthylammonium acetate (TBA) was selected. This was added to the samples before LC/MS/MS analysis to facilitate ethephon chromatographic retention. The acquisition of several specific MS/MS transitions together with the evaluation of their relative intensity ratios allowed the reliable confirmation of the analyte in samples. The optimised approach was tested in low-salinity water spiked at 0.1 µg L−1 level with satisfactory recovery, and a limit of detection of 0.02 µg L−1. To this purpose, the water sample was partially de-ionised in an initial stage, in order to remove major ions that would have interfered in analyses. The application of this methodology to more saline/complex water samples, as surface or wastewater, was problematic and a thorough optimisation of the de-ionisation conditions would be required

    Simultaneous determination of triazines and their main transformation products in surface and urban wastewater by ultra-high-pressure liquid chromatography- tandem mass spectrometry

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    This work describes the optimization, validation and application to real samples of an ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the quantification and confirmation of 11 compounds (atrazine, simazine, terbuthylazine, terbumeton, terbutryn and their main transformation products) in surface and wastewater samples. Most of these analytes are included in the list of priority substances in the framework on European Water Policy. The application of this method to water samples reveals that the most relevant transformation products (TPs) should be incorporated into current analytical methods (which are focused mainly on the determination of unchanged compounds), to obtain a more realistic knowledge on water quality regarding pesticide contamination. TPs are generally more polar and mobile than the parents and they can be transported to the aquatic environment more rapidly than their precursors. Additionally, they can present some degree of toxicity and in fact TPs are also included within the legislation on drinking water as pesticide derivatives. To efficiently combine UHPLC with MS/MS, a fast-acquisition triple quadrupole mass analyzer was used. Working in selected reaction monitoring mode, up to three simultaneous transitions per compound were acquired allowing a reliable identification at ng/L levels. The method developed includes a pre-concentration step based on solid-phase extraction (OASIS HLB cartridges). Satisfactory recoveries (70-120%) and relative standard deviations (<20%) were obtained for all compounds in different water samples types spiked at two concentration levels (0.025 and 0.1 μg/L). The optimized method was found to have excellent sensitivity with instrumental detection limits as low as 50 fg. In addition, the influences of the matrix constituents on ionization efficiency and extraction recovery have been studied in different types of Italian and Spanish surface and urban wastewater. Signal suppressions were observed for all compounds, especially for influent wastewater. The use of isotope-labelled internal standards was found to be the best approach to assure an accurate quantification in all matrix sample

    Pesticide residues and transformation products in groundwater from a Spanish agricultural region on the Mediterranean Coast

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    An overview is given on the presence and changes over time of pesticide residues in groundwater from the Valencia region, one of the most important citrus cultivation sites of southern Europe. A multiresidue LC-MS/MS method was applied for the screening of around 50 pesticides in 75 water samples collected during 2000. The herbicides simazine, terbuthylazine, bromacil, terbumeton, and diuron were the most frequently detected compounds. On the basis of compounds detected in these samples, another method that focused on 30 herbicides and relevant transformation products (TPs) was developed and applied to around 80 water samples collected during 2003. Simazine was the most frequently found compound followed by several triazine metabolites. Data for this paper show the vulnerability of groundwater in this area to herbicide applications and illustrate the importance of including pesticide TPs in environmental monitoring programmes, as four out of the five compounds most frequently detected were pesticide TP

    The use of hydrogen as a potential reductant in the chromite smelting industry

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    The chromium (Cr) content of stainless steel originates from recycled scrap and/or ferrochrome (FeCr), which is mainly produced by the carbothermic reduction of chromite ore. Ever-increasing pressure on FeCr producers to curtail carbon emissions justifies migration from traditional FeCr production routes. The interaction between hydrogen and chromite only yields water, foregoing the generation of significant volumes of CO-rich off-gas during traditional smelting procedures. For this reason, the use of hydrogen as a chromite reductant is proposed. In addition to thermodynamic modelling, the influence of temperature, time, and particle size on the reduction of chromite by hydrogen was investigated. It was determined that, at the explored reduction parameters, the iron (Fe)-oxides presented in chromite could be metalized and subsequently removed by hot-acid leaching. The Cr-oxide constituency of chromite did not undergo appreciable metalization. However, the removal of Fe from the chromite spinel allowed the formation of eskolaite with the composition of (Cr1.4Al0.6)O3 in the form of an exsolved phase, which may adversely affect the reducibility of chromite. The study includes the limitations of incorporating hydrogen as a reductant into existing FeCr production infrastructure and proposes possible approaches and considerations.publishedVersio

    Depth of response in multiple myeloma: A pooled analysis of three PETHEMA/GEM clinical trials

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    On behalf of the GEM (Grupo Español de Mieloma)/PETHEMA (Programa para el Estudio de la Terapéutica en Hemopatías Malignas) Cooperative Study Group.[Purpose]: To perform a critical analysis on the impact of depth of response in newly diagnosed multiple myeloma (MM). [Patients and Methods]: Data were analyzed from 609 patients who were enrolled in the GEM (Grupo Español de Mieloma) 2000 and GEM2005MENOS65 studies for transplant-eligible MM and the GEM2010MAS65 clinical trial for elderly patients with MM who had minimal residual disease (MRD) assessments 9 months after study enrollment. Median follow-up of the series was 71 months. [Results]: Achievement of complete remission (CR) in the absence of MRD negativity was not associated with prolonged progression-free survival (PFS) and overall survival (OS) compared with near-CR or partial response (median PFS, 27, 27, and 29 months, respectively; median OS, 59, 64, and 65 months, respectively). MRD-negative status was strongly associated with prolonged PFS (median, 63 months; P operational cure> was high; median PFS was 12 years, and the 10-year OS rate was 94%. [Conclusion]: Our results demonstrate that MRD-negative status surpasses the prognostic value of CR achievement for PFS and OS across the disease spectrum, regardless of the type of treatment or patient risk group. MRD negativity should be considered as one of the most relevant end points for transplant-eligible and elderly fit patients with MM.Supported by the Centro de Investigación Biomédica en Red – Area de Oncologia - del Instituto de Salud Carlos III (CIBERONC; CB16/12/00369; CB16/12/00400; CB16/12/00233; CB16/12/00284), formerly named as Cooperative Research Thematic Network (Grants No. RD12/0036/0058, RD12/0036/0048, RD12/0036/0046, and RD12/0036/0061) of the Red de Cancer (Cancer Network of Excellence); Instituto de Salud Carlos III/Subdirección General de Investigación Sanitaria; funded in part by the European Regional Development Fund (FIS No. 98/1239, 00/10160, 01/0089, 02/0089, 02/0905, G03/136, PI051284, PI06033906/1354, PS09/01897/01370, PI12/01761, PI12/02311, PI13/01469, PI14/01867, G03/136); Sara Borrell (No. CD13/00340); Asociación Española Contra el Cáncer (No. GCB120981SAN); and Federación Española de Enfermedades Raras. Also supported internationally by the Black Swan Research Initiative of the International Myeloma Foundation and the European Research Council 2015 Starting Grant (MYELOMANEXT).Peer Reviewe

    Single nucleotide polymorphisms in DNA repair genes as risk factors associated to prostate cancer progression

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    Background Besides serum levels of PSA, there is a lack of prostate cancer specific biomarkers. It is need to develop new biological markers associated with the tumor behavior which would be valuable to better individualize treatment. The aim of this study was to elucidate the relationship between single nucleotide polymorphisms (SNPs) in genes involved in DNA repair and prostate cancer progression.Methods A total of 494 prostate cancer patients from a Spanish multicenter study were genotyped for 10 SNPs in XRCC1, ERCC2, ERCC1, LIG4, ATM and TP53 genes. The SNP genotyping was made in a Biotrove OpenArray® NT Cycler. Clinical tumor stage, diagnostic PSA serum levels, and Gleason score at diagnosis were obtained for all participants. Genotypic and allelic frequencies were determined using the web-based environment SNPator.Results SNPs rs11615 (ERCC1) and rs17503908 (ATM) appeared as risk factors for prostate cancer aggressiveness. Patients wild homozygous for these SNPs (AA and TT, respectively) were at higher risk for developing cT2b – cT4 (OR = 2.21 (confidence interval (CI) 95% 1.47 – 3.31), p < 0.001) and Gleason scores ≥ 7 (OR = 2.22 (CI 95% 1.38 – 3.57), p < 0.001), respectively. Moreover, those patients wild homozygous for both SNPs had the greatest risk of presenting D’Amico high-risk tumors (OR = 2.57 (CI 95% 1.28 – 5.16)).Conclusions Genetic variants at DNA repair genes are associated with prostate cancer progression, and would be taken into account when assessing the malignancy of prostate cancer.This work was subsidized by a grant from the Instituto de Salud Carlos III (Ministerio de Economía y Competitividad from Spain), ID: PI12/01867. Almudena Valenciano has a grant from the Instituto Canario de Investigación del Cáncer (ICIC)

    Depth of Response in Multiple Myeloma: A Pooled Analysis of Three PETHEMA/GEM Clinical Trials

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    [EN] Purpose—To perform a critical analysis on the impact of depth of response in newly diagnosed multiple myeloma (MM). Patients and Methods—Data were analyzed from 609 patients who were enrolled in the GEM (Grupo Español de Mieloma) 2000 and GEM2005MENOS65 studies for transplant-eligible MM and the GEM2010MAS65 clinical trial for elderly patients with MM who had minimal residual disease (MRD) assessments 9 months after study enrollment. Median follow-up of the series was 71 months. Results—Achievement of complete remission (CR) in the absence of MRD negativity was not associated with prolonged progression-free survival (PFS) and overall survival (OS) compared with near-CR or partial response (median PFS, 27, 27, and 29 months, respectively; median OS, 59, 64, and 65 months, respectively). MRD-negative status was strongly associated with prolonged PFS (median, 63 months; P < .001) and OS (median not reached; P < .001) overall and in subgroups defined by prior transplantation, disease stage, and cytogenetics, with prognostic superiority of MRD negativity versus CR particularly evident in patients with high-risk cytogenetics. Accordingly, Harrell C statistics showed higher discrimination for both PFS and OS in Cox models that included MRD (as opposed to CR) for response assessment. Superior MRD-negative rates after different induction regimens anticipated prolonged PFS. Among 34 MRD-negative patients with MM and a phenotypic pattern of bone marrow involvement similar to monoclonal gammopathy of undetermined significance at diagnosis, the probability of “operational cure” was high; median PFS was 12 years, and the 10-year OS rate was 94%. Conclusion—Our results demonstrate that MRD-negative status surpasses the prognostic value of CR achievement for PFS and OS across the disease spectrum, regardless of the type of treatment or patient risk group. MRD negativity should be considered as one of the most relevant end points for transplant-eligible and elderly fit patients with MM

    Relationship between olive oil consumption and ankle-brachial pressure index in a population at high cardiovascular risk

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    The aim of this study was to ascertain the association between the consumption of different categories of edible olive oils (virgin olive oils and olive oil) and olive pomace oil and ankle-brachial pressure index (ABI) in participants in the PREDIMED-Plus study, a trial of lifestyle modification for weight and cardiovascular event reduction in individuals with overweight/obesity harboring the metabolic syndrome. Methods: We performed a cross-sectional analysis of the PREDIMED-Plus trial. Consumption of any category of olive oil and olive pomace oil was assessed through a validated food-frequency questionnaire. Multivariable linear regression models were fitted to assess associations between olive oil consumption and ABI. Additionally, ABI ≤1 was considered as the outcome in logistic models with different categories of olive oil and olive pomace oil as exposure. Results: Among 4330 participants, the highest quintile of total olive oil consumption (sum of all categories of olive oil and olive pomace oil) was associated with higher mean values of ABI (beta coefficient: 0.014, 95% confidence interval [CI]: 0.002, 0.027) (p for trend = 0.010). Logistic models comparing the consumption of different categories of olive oils, olive pomace oil and ABI ≤1 values revealed an inverse association between virgin olive oils consumption and the likelihood of a low ABI (odds ratio [OR] 0.73, 95% CI [0.56, 0.97]), while consumption of olive pomace oil was positively associated with a low ABI (OR 1.22 95% CI [1.00, 1.48]). Conclusions: In a Mediterranean population at high cardiovascular risk, total olive oil consumption was associated with a higher mean ABI. These results suggest that olive oil consumption may be beneficial for peripheral artery disease prevention, but longitudinal studies are needed

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Unidad de excelencia María de Maeztu CEX2019-000940-MAim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

    Estimating the global conservation status of more than 15,000 Amazonian tree species

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    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict thatmost of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century
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