897 research outputs found
Synthesis and proton conduction properties of lanthanide amino-sulfophosphonates
Acidic groups-containing metal phosphonates exhibit a wide range of proton
conductivity depending on the water content and functionality. Moreover, this property can
be enhanced by appropriate post-synthesis chemical and/or thermal treatments [1,2].
In this work, focus is laid on properties derived from the combination of lanthanide ions
with the amino-sulfophosphonate ligand (H2O3PCH2)2-N-(CH2)2-SO3H. Highthrough-put
screening was used to reach the optimal synthesis conditions under hydrothermal
conditions at 140 ÂșC. Isolated polycrystalline solids, Ln[(O3PCH2)2-NH-(CH2)2-SO3H]·2H2O
(Ln= La, Pr, Sm, Eu, Gd, Tb and Er), crystallize in the monoclinic (La and Er) and
orthorhombic (Pr, Sm, Eu, Gd and Tb) systems with unit cell volume of ~1200 and 2548 Ă
3
respectively. Their crystal structures, solved ab initio from X-ray powder diffraction data,
correspond to different layered frameworks depending on the lanthanide cation size. Thus,
compounds with orthorhombic symmetry show free acidic sulfonic pointing to the interlayer
space, while La- and Er- derivatives display layered structures where both phosphonate
and sulfonated groups are coordinated to the metal, leaving free P-OH groups. As
consequence of this structural variability, different H-bond networks and proton transfer
pathways are generated. Preliminary proton conductivity measurements have been carried
out between 25 and 80 ÂșC at 70-95 % relative humidity. The sample exhibits conductivities
near to 3.10-3 S.cm-1 and activation energies characteristics of a Grotthuss-type
mechanism of proton transfer.Proyectos de investigación del ministerio MICINN, Españam(MAT2016-77648-R),
Proyectos de la Junta de AndalucĂa (P12-FQM-1656),
Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Structure-properties correlations in divalent metal phosphonates
Crystalline metal phosphonates may offer acidic sites, structural flexibility and guest molecules (H2O, heterocyclics, etc.) which can act as proton carriers. In addition, some frameworks are also amenable for postâsynthesis modifications in order to enhance desired properties [1,2].
In this work, we present the synthesis and structural characterization of two hydroxyphosphonoacetates hybrids based on magnesium, [Mg5(O3PCHOHCOO)2(HO3PCHOHCOO)2·8H2O] [Mg5(HPAA)2(H1HPAA)2·8H2O], and zinc, [Zn6K(O3PCHOHCOO)4(OH)·6.5H2O] [Zn6K(HPAA)4(OH)·6.5H2O]. Both solids present three-dimensional frameworks and their crystal structures were solved ab initio from X-ray powder diffraction. The proton conductivity of [Zn6K(HPAA)4(OH)·6.5H2O] as well as ammonia derivatives of M(II)(HO3PCHOHCOO)·2H2O [M(II)=Zn, Mg] will be reported and discussed.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech. FQM-1656; MAT2013-41836-
Analysis of the invasion of water lilies (Eichhornia crassipes (Mart) Solms) in the Cointzio dam, MichoacĂĄn, Mexico
Objective: to analyze the growth dynamics of the water lily (Eichhornia crassipes) in the Cointzio dam due to the availability of water.
Design/Methodology/Approach: a monthly series of 45 Sentinel 2 and Landsat satellite images was used, with which the percentage of invasion of the water lily in the total area of the reservoir was calculated. The relative coverage of the lily was analyzed looking for growth patterns over time, as well as precipitation data, total reservoir area over time, and water storage data in the 2010-2020 period to broaden the context.
Results: Three ascending and two descending patterns of the water lily cover were identified; a 15-month upward growth pattern with slight inland slope changes; decreasing patterns are associated with decreased storage. The largest lily covers were found in critical storage stages during the 2010-2020 period.
Study limitations/implications: faced with climate change conditions, the filling pattern of the dam could change, aggravating problems related to water supply.
Conclusions: containment/mitigation efforts have a reduced effect because the lily recovers the covered area easily, growing about 400% between October 2017 and June 2018, so it is necessary to implement a containment strategy using the biophysical interactions of the basin in conjunction with social, political, economic and governance interactions.Objective: to analyze the growth dynamics of the water lily (Eichhornia crassipes)in the Cointzio dam due to the water availability.Design/Methodology/Approach: a monthly series of 45 Sentinel 2 and Landsatsatellite images were used, with which the percentage of invasion of the water lilyin the total area of the reservoir was calculated. The relative coverage of the lilywas analyzed looking for growth patterns over time, as well as the precipitationdata, total reservoir area over time, and water storage data for the 2010-2020period to broaden its context.Results: Three ascending and two descending patterns of the water lily coveragewere identified; a 15-month upward growth pattern with slight inland slope changes; decreasing patterns are associated with decreased water storage. Thelargest lily covers were found in critical storage stages during the 2010-2020period.Study limitations/implications: faced with climate change conditions, the fillingpattern of the dam could change, aggravating problems related to the water supply.Conclusions: containment/mitigation efforts have a reduced effect because the lilyeasily recovers the covered area, growing about 400% between October 2017 andJune 2018, therefore it is necessary to implement a containment strategy using thebiophysical interactions of the basin in conjunction with social, political, economicand governance interactions
Photodegradation of Phenol over a Hybrid Organo-Inorganic Material: Iron(II) Hydroxyphosphonoacetate
Water treatment is a hot topic, and it will become much more important in the decades ahead. Advanced oxidation processes are being increasingly used for organic contaminant removal, for example using photo-Fenton reactions. Here we report the use of an organo-inorganic hybrid, Fe[HO3PCH(OH)COO]·2H2O, as Fenton photocatalyst for phenol oxidation with H2O2 under UVA radiation. Preactivation, catalyst content, and particle size parameters have been studied/optimized for increasing phenol mineralization. Upon reaction, iron species are leached from the catalyst making a homogeneous catalysis contribution to the overall phenol photo-oxidation. Under optimized conditions, the mineralization degree was slightly larger than 90% after 80 min of irradiation. Analysis by X-ray photoelectron spectroscopy revealed important chemical modifications occurring on the surface of the catalyst after activation and phenol photodegradation. The sustained slow delivery of iron species upon phenol photoreaction is advantageous as the mixed heterogeneousâhomogeneous catalytic processes result in very high phenol mineralization.Proyecto nacional MAT2010-1517
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
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in âs=13âTeV 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 âs=13ââTeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139ââfbâ1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015â2016 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
Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector
A search for the direct production of the supersymmetric partners ofÏ-leptons (staus) in final stateswith two hadronically decayingÏ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fbâ1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneÏ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino
Factors associated with sentinel lymph node status and prognostic role of completion lymph node dissection for thick melanoma
Surgical treatment for colorectal cancer: Analysis of the influence of an enhanced recovery programme on long-term oncological outcomes-a study protocol for a prospective, multicentre, observational cohort study
Introduction The evidence currently available from enhanced recovery after surgery (ERAS) programmes concerns their benefits in the immediate postoperative period, but there is still very little evidence as to whether their correct implementation benefits patients in the long term. The working hypothesis here is that, due to the lower response to surgical aggression and lower rates of postoperative complications, ERAS protocols can reduce colorectal cancer-related mortality. The main objective of this study is to analyse the impact of an ERAS programme for colorectal cancer on 5-year survival. As secondary objectives, we propose to analyse the weight of each of the predefined items in the oncological results as well as the quality of life. Methods and analysis A multicentre prospective cohort study was conducted in patients older than 18 years of age who are scheduled to undergo surgery for colorectal cancer. The study involved 12 hospitals with an implemented enhanced recovery protocol according to the guidelines published by the Spanish National Health Service. The intervention group includes patients with a minimum implementation level of 70%, and the control group includes those who fail to reach this level. Compliance will be studied using 18 key performance indicators, and the results will be analysed using cancer survival indicators, including overall survival, cancer-specific survival and relapse-free survival. The time to recurrence, perioperative morbidity and mortality, hospital stay and quality of life will also be studied, the latter using the validated EuroQol Five questionnaire. The propensity index method will be used to create comparable treatment and control groups, and a multivariate regression will be used to study each variable. The Kaplan-Meier estimator will be used to estimate survival and the log-rank test to make comparisons. A p value of less than 0.05 (two-tailed) will be considered to be significant. Ethics and dissemination Ethical approval for this study was obtained from the Aragon Ethical Committee (C.P.-C.I. PI20/086) on 4 March 2020. The findings of this study will be submitted to peer-reviewed journals (BMJ Open, JAMA Surgery, Annals of Surgery, British Journal of Surgery). Abstracts will be submitted to relevant national and international meetings.The present research study was awarded a Ministerio de Ciencia e
InnovaciĂłn health research project grant (PI19/00291) from the Carlos III Institute
of the Spanish National Health Service as part of the 2019 call for Strategic Action
in Health
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