1,672 research outputs found
Heavy metals transport in typical portuguese loamy sand soils
Illegal discharges are of great concern among industry activities, since they occur under
uncontrolled conditions. In most cases, effluents are acidic and the concentrations of heavy
metals are very high. With this in mind, the main goal of this study was to evaluate the
sorption of two of the most toxic heavy metals, Cr(VI) and Pb(II), in those conditions.
A loamy sand soil was collected in Oporto, Portugal. Batch equilibrium and kinetic sorption
experiments were performed using both metals solutions, with concentrations among 50 mg
L-1 and 200 mg L-1, at pH 2 and 5, between 2 h and 288 h.
To evaluate the sorption equilibrium, eight isotherm models were fitted. Better adjustments
were observed for the Redlich-Peterson and Khan models for the adsorption of chromium (R2
= 0.99), and of lead (R2 = 0.99), respectively. The sorption kinetics was evaluated using three
models – Elovich, Pseudo first order and an empirical power function. The retention of lead
was almost instantaneous and the empirical power function described better the sorption
kinetics of chromium (0.89 < R2 < 0.99).
In addition, flow experiments were performed with effluents of both metals (50 mg L-1) at pH
2 and 5, for about 90 h. Results revealed a high retention of chromium, and a weak retention
of lead, for low pH values. FTIR analyses to the columns samples revealed that clay minerals
have an important role in the retention of both metals
Levels of evidence in plastic surgery – Trends and comparison with five other surgical specialties
Background: Categorising research by level of evidence (LOE) is an important evidence-based medicine initiative. Our objective was to assess the change in LOEs in plastic surgery from 2003 to 2013 and compared this with five other surgical specialties. Methods: A search for all research articles published in the top three general plastic surgery journals (ranked by impact factor) was conducted for 2003 and 2013. Articles were then labelled as LOE 1–5 and compared to other specialties. Results: Mean LOE for plastic surgery improved by 4.1Â % from 3.86 (95Â % confidence interval 3.81–3.91) to 3.70 (95Â % confidence interval 3.64–3.74) from 2003 to 2013 respectively. All six surgical specialties improved their mean LOE (range 3.7 to 10.9Â %). By mean LOE, plastic surgery continues to rank five out of six. Conclusions: Plastic surgery is tending towards higher levels of evidence at a slow pace. The specialty must continue to drive towards higher levels of evidence. Level of Evidence: Not ratable
Accuracy of a method based on atomic absorption spectrometry to determine inorganic arsenic in food : Outcome of the collaborative trial IMEP-41
Peer reviewedPublisher PD
Mobile phone use and glioma risk: comparison of epidemiological study results with incidence trends in the United States
Objective In view of mobile phone exposure being classified as a possible human carcinogen by the International Agency for Research on Cancer (IARC), we determined the compatibility of two recent reports of glioma risk (forming the basis of the IARC’s classification) with observed incidence trends in the United States
Library of Seleno-Compounds as Novel Agents against Leishmania Species
The in vitro leishmanicidal activities of a series of 48 recently synthesized selenium derivatives against Leishmania infantum and Leishmania braziliensis parasites were tested using promastigotes and intracellular amastigote forms. The cytotoxicity of the tested compounds for J774.2 macrophage cells was also measured in order to establish their selectivity. Six of the tested compounds (compounds 8, 10, 11, 15, 45, and 48) showed selectivity indexes higher than those of the reference drug, meglumine antimonate (Glucantime), for both Leishmania species; in the case of L. braziliensis, compound 20 was also remarkably selective. Moreover, data on infection rates and amastigote numbers per macrophage showed that compounds 8, 10, 11, 15, 45, and 48 were the most active against both Leishmania species studied. The observed changes in the excretion product profile of parasites treated with these six compounds were also consistent with substantial cytoplasmic alterations. On the other hand, the most active compounds were potent inhibitors of Fe superoxide dismutase (Fe-SOD) in the two parasite species considered, whereas their impact on human CuZn-SOD was low. The high activity, low toxicity, stability, low cost of the starting materials, and straightforward synthesis make these compounds appropriate molecules for the development of affordable antileishmanicidal agents
Accuracy of a method based on atomic absorption spectrometry to determine inorganic arsenic in food: outcome of the collaborative trial IMEP-41
A collaborative trial was conducted to determine the performance characteristics of an analytical method for the quantification of inorganic arsenic (iAs) in food. The method is based on (i) solubilisation of the protein matrix with concentrated hydrochloric acid to denature proteins and allow the release of all arsenic species into solution, and (ii) subsequent extraction of the inorganic arsenic present in the acid medium using chloroform followed by back-extraction to acidic medium. The final detection and quantification is done by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS). The seven test items used in this exercise were reference materials covering a broad range of matrices: mussels, cabbage, seaweed (hijiki), fish protein, rice, wheat, mushrooms, with concentrations ranging from 0.074 to 7.55 mg kg(-1). The relative standard deviation for repeatability (RSDr) ranged from 4.1 to 10.3%, while the relative standard deviation for reproducibility (RSDR) ranged from 6.1 to 22.8%. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
DD04107-Derived neuronal exocytosis inhibitor peptides: Evidences for synaptotagmin-1 as a putative target
The analgesic peptide DD04107 (Pal-EEMQRR-NH2) and its acetylated analogue inhibit a-calcitonin gene-related peptide (a-CGRP) exocytotic release from primary sensory neurons. Examining the crystal structure of the SNARE-Synaptotagmin-1(Syt1) complex, we hypothesized that these peptides could inhibit neuronal exocytosis by binding to Syt1, hampering at least partially its interaction with the SNARE complex. To address this hypothesis, we first interrogate the role of individual side-chains on the inhibition of a-CGRP release, finding that E1, M3, Q4 and R6 residues were crucial for activity. CD and NMR conformational analysis showed that linear peptides have tendency to adopt a-helical conformations, but the results with cyclic analogues indicated that this secondary structure is not needed for activity. Isothermal titration calorimetry (ITC) measurements demonstrate a direct interaction of some of these peptides with Syt1-C2B domain, but not with Syt7-C2B region, indicating selectivity. As expected for a compound able to inhibit a-CGRP release, cyclic peptide derivative Pal-E-cyclo[EMQK]R-NH2 showed potent in vivo analgesic activity, in a model of inflammatory pain. Molecular dynamics simulations provided a model consistent with KD values for the interaction of peptides with Syt1-C2B domain, and with their biological activity. Altogether, these results identify Syt1 as a potential new analgesic target. © 202
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
Oral ulcer as an exclusive sign of gastric cancer: report of a rare case
BACKGROUND: The oral cavity is a rare but occasional target for metastases, which may masquerade as various benign and inflammatory lesions, and sometimes also be asymptomatic. Oral metastatic lesions have been described in various cancers, particularly lung, breast and kidney carcinoma. CASE PRESENTATION: We here describe an uncommon case of a hard palate mucosa and gingival metastasis from gastric carcinoma that was originally diagnosed as a periodontal disease. Histopathological examination of a biopsy of the lesion revealed a signet-ring cell carcinoma, and a subsequent biopsy of an ulcerated stomach lesion showed a poorly differentiated gastric carcinoma. The patient underwent gastric resection but died of heart failure on the tenth postoperative day; a post-mortem examination revealed a residual bilateral ovarian infiltration by gastric carcinoma (Krukenberg's tumor). CONCLUSION: An occult carcinoma of the stomach may rarely metastasise to the oral cavity even as a first and exclusive manifestation; it is important to bear this possibility in mind because such conditions may mimic a benign disease
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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