27 research outputs found
A Chiral Bipyrimidine-Bridged Dy2 SMM: A Comparative Experimental and Theoretical Study of the Correlation Between the Distortion of the DyO6N2 Coordination Sphere and the Anisotropy Barrier
Chiral bipyrimidine-bridged dinuclear LnIII complexes of general formula
[(μ-bipym){((+)-tfacam)3Ln}2] and [(μ-bipym){((-)-tfacam)3Ln}2], have been prepared
from the assembly of Ln(AcO)3·nH2O (LnIII = Dy, Gd), (+)/(−)-3-(trifluoroacetyl)camphor
enantiopure ligands ((+)/(-)-Htfacam) and bipyrimidine (bipym). The structure and
chirality of these complexes have been supported by single-crystal X-Ray diffraction
and circular dichroism. The study of the magnetic properties of the GdIII complexes
revealed a very weak antiferromagnetic interaction between the GdIII ions through the
bipyrimidine bridging ligand. Ab initio CASSCF calculations indicated that the ground
Kramers doublet (KD) of both DyIII centers is almost purely axial with the anisotropy axis
located close to the two tfacam−ligands at opposite sides of each DyIIIatom, which
create an axial crystal field. In keeping with this, ac dynamic measurements indicated
slow relaxation of the magnetization at zero field with Ueff = 55.1 K, a pre-exponential
factor of τo = 2.17·10−6 s and τQTM = 8 μs. When an optimal dc field of 0.1 T is
applied, QTM is quenched and Ueff increases to 75.9 K with τo = 6.16 × 10−7 s. The
DyN2O8 coordination spheres and SMM properties of [(μ-bipym){((+)-tfacam)3Ln}2]
and their achiral [(Dy(b-diketonate)3)2(μ-bpym)]analogous have been compared and a
magneto-structural correlation has been established, which has been supported by
theoretical calculations.ID-O, JH, and EC are grateful to Ministerio de Economía y
Competitividad (MINECO) for Project CTQ2014-56312-P, the
Junta de Andalucía (FQM-195 and the Project of excellence
P11-FQM-7756) and the University of Granada. A part of this
work has been made at HFLSM, IMR, Tohoku University. IDO
also acknowledges support by COLABS. GR would like to
thank SERB (EMR/2014/000247) for financial support. SDthanks
UGC for Senior Research Fellowship. AC thanks the Marie
Curie COFUND Action from the European Commission for
co-financing his postdoctoral fellowship
A Pilot Study on the Feasibility of Developing and Implementing a Mobile App for the Acquisition of Clinical Knowledge and Competencies by Medical Students Transitioning from Preclinical to Clinical Years
Due to the COVID-19 pandemic and the consequent restrictions, universities have had to adapt their curricula substantially to new schemes in which remote learning is of the essence. In this study, we assess the feasibility of developing a mobile app supplementary to the distant teaching paradigm for the “Cardiology” module of the “General Pathology” subject in undergraduate Medical Education, and we evaluate its impact and acceptability. A cohort of volunteer second-year medical students (n = 44) had access to the app, and their opinions on its utility (1–10) were collected. Additionally, the students were invited to refer their expected satisfaction (1–10) with a blended learning methodology overlapping this new tool with the traditional resources. The average expected satisfaction had been compared to the average satisfaction obtained by just the traditional methodology in other modules from the same subject. Through a qualitative approach, we defined the strengths and weaknesses of the tool. Seventy-seven percent of the participants rated at 8/10 or more the potential learning value of the application and, if used as a supplement to traditional teaching, it would also statistically improve the satisfaction of students (6.52 vs. 8.70, p < 0.001). Similarly, the qualitative data corroborated the benefits of such innovation. Multidisciplinary collaborations are encouraged to develop teaching innovations, although further research should aim to better define the effectiveness of learning with these resources
Consistency in climate change impact reports among indigenous peoples and local communities depends on site contexts
Unidad de excelencia María de Maeztu CEX2019-000940-MIndigenous Peoples and local communities are heavily affected by climatic changes. Investigating local understandings of climate change impacts, and their patterned distribution, is essential to effectively support monitoring and adaptation strategies. In this study, we aimed to understand the consistency in climate change impact reports and factors influencing consistency at site and individual levels. We conducted cross-cultural research among iTaukei (Fiji), Dagomba (Ghana), fisherfolks (Tanzania), Tsimane' (Bolivia), Bassari (Senegal), ribeirinhos (Brazil), Mapuche (Chile), Mongolian (China), Tibetan (China) and Daasanach (Kenya) communities using semi-structured interviews, focus groups, and surveys among 1860 individuals. We found that cross-culturally more than two-thirds of individual reports of climate change impacts match site-confirmed reports. Consistency in reports is higher for changes related to pastoralism than crop production and wild plant gathering. Individual's experience with nature, Indigenous and local knowledge, and local family roots are not significantly associated with consistency across sites, but site-specific associations are prevalent. Despite high average consistency among sites, there is considerable variation caused by site-specific factors, including livelihood activities, socio-cultural settings, and environmental conditions. Site contexts and related consistency in climate change impact reports need to be taken into account for climate change monitoring and adaptation planning
Aminopropyltriethoxysilane functionalized MCM-41 and SBA-15 nanostructured materials for carbon dioxide adsorption
The design of effective CO2 capture materials is a current challenge. Here, we report the synthesis of aminosilanes-functionalized MCM-41 and SBA-15 materials with high efficiency toward carbon dioxide adsorption. The functionalization of the mesoporous silicas involves a post-synthesis method by impregnation with 3-aminopropyltriethoxysilane. The carbon dioxide adsorption capacities for the samples were carried out under ambient pressures. The results evidenced that aminosilanes with a terminal amine were functionalized through covalent coupling of this group onto the channels' surface in the ordered mesoporous silica. It means that the amine is anchored on the surface of the largest pores of the MCM-41 and SBA-15 supports. The Lagergren kinetic model evidenced the enhanced carbon dioxide adsorption capacity and stability of the functionalized ordered mesoporous molecular sieves.Keywords: 3-Aminopropyltriethoxysilane; Carbon dioxide; Functionalization; MCM-41; SBA-15.
Preparation, characterization and catalytic applications of ZrO2 supported on low cost SBA-15
This work presents some applications of ZrO2 supported over SBA-15 silica as promoter of sulfated zirconia and as support from CuO/CeO 2 catalytic system for preferential oxidation of CO to CO2 in hydrogen rich streams, used as feed for proton exchange membrane fuel cells (PEMFC). Different amounts of ZrO2, from 10 to 30 wt.% were incorporated. These prepared materials were characterized by powder XRD, adsorption-desorption of N2 at 77 K, transmission and scanning electron microscopy (TEM and SEM) and X-rays photoelectron spectroscopy (XPS). The acidity was studied by thermo-programmed desorption of ammonia (NH 3-TPD). These materials were tested, after treatment with H 2SO4, by 2-propanol dehydration and 1-butene isomerization catalytic tests. The samples were found quite good catalyst with strong acid sites, the sample with 20 wt.% of ZrO2 being the better performing sample. Finally this material was successfully used as support for a CuO/CeO2 system, with 6 wt.% of Cu and 20 wt.% of Ce. The resulting catalyst was tested in the preferential oxidation of CO (CO-PROX) attaining conversions close to 100% and high selectivity to CO2
Metabolic reprogramming by Acly inhibition using SB-204990 alters glucoregulation and modulates molecular mechanisms associated with aging
19 Páginas.-- 7 FigurasATP-citrate lyase is a central integrator of cellular metabolism in the interface of protein, carbohydrate, and lipid metabolism. The physiological consequences as well as the molecular mechanisms orchestrating the response to long-term pharmacologically induced Acly inhibition are unknown. We report here that the Acly inhibitor SB-204990 improves metabolic health and physical strength in wild-type mice when fed with a high-fat diet, while in mice fed with healthy diet results in metabolic imbalance and moderated insulin resistance. By applying a multiomic approach using untargeted metabolomics, transcriptomics, and proteomics, we determined that, in vivo, SB-204990 plays a role in the regulation of molecular mechanisms associated with aging, such as energy metabolism, mitochondrial function, mTOR signaling, and folate cycle, while global alterations on histone acetylation are absent. Our findings indicate a mechanism for regulating molecular pathways of aging that prevents the development of metabolic abnormalities associated with unhealthy dieting. This strategy might be explored for devising therapeutic approaches to prevent metabolic diseases.This work was funded by grants from the Ministerio de Economía y Competitividad, Instituto de Salud Carlos III, co-funded by Fondos FEDER (PI15/00134, PI18/01590, CPII19/00023 to A.M.M.) and the Ministerio de Ciencia e Innovación (PID2021-123965OB-100 to A.M.M.). A.M.M. is funded by the Junta de Andalucía P20_00480, the Spanish Society of Diabetes, and CSIC 202220I059. M.S.K. is funded by the Nordea Foundation (#02-2017-1749), the Novo Nordisk Foundation (#NNF17OC0027812), the Neye Foundation, the Lundbeck Foundation (#R324-2019-1492), the Ministry of Higher Education and Science of Denmark (#0238-00003B). V.C.G. is funded by the Instituto de Salud Carlos III (CP19/00046), co-funded by FEDER. F.M. is funded by the CIBERDEM of the Instituto de Salud Carlos III. A.M.M. is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. We acknowledge the support of the group of basic research on diabetes of the Spanish Society of Diabetes.Peer reviewe
Characterization of (Sn and Cu)/Pd catalysts for the nitrate reduction in natural water
[EN] The aim of this work is to characterize different (Cu and Sn)/Pd catalysts, supported on alumina, used
for the catalytic removal of nitrates in natural water. The catalysts have been prepared with a Pd/(Cu or
Sn) ratio of 2 but with different metal contents. Their activity and selectivity have been studied using
a continuous stirred-tank reactor with nitrate polluted water from an aquifer. The catalysts have been
characterized both before and after reaction by XPS, XRD, XRF, adsorption–desorption N2 isotherms at
196 ◦C and TEM. XPS results show changes of the Pd/Sn surface atomic ratio upon catalyst activation and
after reaction and the coexistence of different oxidation states for the active metals. The studied catalysts
are active, being the catalyst with the best performance that with the highest metallic dispersion and
with the lowest phases segregation. The characterization ofthe catalysts after reaction shows that catalyst
deactivation could be related with the non-reversible oxidation of the Sn–Pd couple.We gratefully acknowledge the support from the Ministry of Science and Innovation, Spain (MICINN, Spain) through the project MAT2009-10481 and FEDER funds. Authors also thank the Spanish Government (projects MAT2009-14528-C02-01 and CONSOLIDER INGENIO 2010) and the European Union (European Community's Seventh Framework Programme FP7/2007-2013 under Grant Agreement No. 226347 Project) for financial support.Franch Martí, C.; ENRIQUE RODRIGUEZ-CASTELLON; Reyes-Carmona, Á.; Palomares Gimeno, AE. (2012). Characterization of (Sn and Cu)/Pd catalysts for the nitrate reduction in natural water. Applied Catalysis A: General. 425-426:142-152. https://doi.org/10.1016/j.apcata.2012.03.015Senia142152425-42
Characterization of (Sn and Cu)/Pd catalysts for the nitrate reduction in natural water
[EN] The aim of this work is to characterize different (Cu and Sn)/Pd catalysts, supported on alumina, used
for the catalytic removal of nitrates in natural water. The catalysts have been prepared with a Pd/(Cu or
Sn) ratio of 2 but with different metal contents. Their activity and selectivity have been studied using
a continuous stirred-tank reactor with nitrate polluted water from an aquifer. The catalysts have been
characterized both before and after reaction by XPS, XRD, XRF, adsorption–desorption N2 isotherms at
196 ◦C and TEM. XPS results show changes of the Pd/Sn surface atomic ratio upon catalyst activation and
after reaction and the coexistence of different oxidation states for the active metals. The studied catalysts
are active, being the catalyst with the best performance that with the highest metallic dispersion and
with the lowest phases segregation. The characterization ofthe catalysts after reaction shows that catalyst
deactivation could be related with the non-reversible oxidation of the Sn–Pd couple.We gratefully acknowledge the support from the Ministry of Science and Innovation, Spain (MICINN, Spain) through the project MAT2009-10481 and FEDER funds. Authors also thank the Spanish Government (projects MAT2009-14528-C02-01 and CONSOLIDER INGENIO 2010) and the European Union (European Community's Seventh Framework Programme FP7/2007-2013 under Grant Agreement No. 226347 Project) for financial support.Franch Martí, C.; ENRIQUE RODRIGUEZ-CASTELLON; Reyes-Carmona, Á.; Palomares Gimeno, AE. (2012). Characterization of (Sn and Cu)/Pd catalysts for the nitrate reduction in natural water. Applied Catalysis A: General. 425-426:142-152. https://doi.org/10.1016/j.apcata.2012.03.015S142152425-42
Enhanced activity and acid pH stability of Prussian blue-type oxygen evolution electrocatalysts processed by chemical etching
The development of upscalable oxygen evolving electrocatalysts from earth-abundant metals able to operate in neutral or acidic environments and low overpotentials remains a fundamental challenge for the realization of artificial photosynthesis. In this study, we report a highly active phase of heterobimetallic cyanide-bridged electrocatalysts able to promote water oxidation under neutral, basic (pH 1). Cobalt-iron Prussian blue-type thin films, formed by chemical etching of Co(OH)₁.₀ (CO₃)₀.₅·nH₂O nanocrystals, yield a dramatic enhancement of the catalytic performance toward oxygen production, when compared with previous reports for analogous materials. Electrochemical, spectroscopic, and structural studies confirm the excellent performance, stability, and corrosion resistance, even when compared with state-of-the-art metal oxide catalysts under moderate overpotentials and in a remarkably large pH range, including acid media where most cost-effective water oxidation catalysts are not useful. The origin of the superior electrocatalytic activity toward water oxidation appears to be in the optimized interfacial matching between catalyst and electrode surface obtained through this fabrication method
Enhanced Activity and Acid pH Stability of Prussian Blue-type Oxygen Evolution Electrocatalysts Processed by Chemical Etching
The development of upscalable oxygen
evolving electrocatalysts from earth-abundant metals able to operate
in neutral or acidic environments and low overpotentials remains a
fundamental challenge for the realization of artificial photosynthesis.
In this study, we report a highly active phase of heterobimetallic
cyanide-bridged electrocatalysts able to promote water oxidation under
neutral, basic (pH < 13), and acidic conditions (pH > 1). Cobalt–iron
Prussian blue-type thin films, formed by chemical etching of Co(OH)<sub>1.0</sub>(CO<sub>3</sub>)<sub>0.5</sub>·<i>n</i>H<sub>2</sub>O nanocrystals, yield a dramatic enhancement of the catalytic
performance toward oxygen production, when compared with previous
reports for analogous materials. Electrochemical, spectroscopic, and
structural studies confirm the excellent performance, stability, and
corrosion resistance, even when compared with state-of-the-art metal
oxide catalysts under moderate overpotentials and in a remarkably
large pH range, including acid media where most cost-effective water
oxidation catalysts are not useful. The origin of the superior electrocatalytic
activity toward water oxidation appears to be in the optimized interfacial
matching between catalyst and electrode surface obtained through this
fabrication method