44 research outputs found
Molecular dynamics simulations of defect production in graphene by carbon irradiation
We present molecular dynamics simulations with empirical potentials to study the type of defects produced when irradiating graphene with low energy carbon ions (100 eV and 200 eV) and different dose rates. Simulations show the formation of very stable structures such as dimers, single chains of carbons and double chains of carbons. These structures are similar to those described in the literature, observed experimentally when irradiating graphene. For high doses or dose rates, the formation of nanopores is observed, similar to previous results by other authors for higher energies of the implanted ions. These simulations show how tunning the different parameters of irradiation conditions can be used to selectively create defects in graphene.This work is supported by the Generalitat Valenciana through grant reference PROMETEO2012/011 and the Spanish government through grant FIS2010-21883
Controlled rippling of graphene via irradiation and applied strain modify its mechanical properties: a nanoindentation simulation study
Ripples, present in free standing graphene, have an important influence in the mechanical behavior of this two-dimensional material. In this work we show through nanoindentation simulations, how out-of-plane displacements can be modified by strain resulting in softening of the membrane under compression and stiffening under tension. Irradiation also induces changes in the mechanical properties of graphene. Interestingly, compressed samples, irradiated at low doses are stiffened by the irradiation while samples under tensile strain do not show significant changes in their mechanical properties. These simulations indicate that vacancies, produced by the energetic ions, cannot be the ones directly responsible for this behavior. However, changes in roughness induced by the momentum transferred from the energetic ions to the membrane, can explain these differences. These results provide an alternative explanation to recent experimental observations of stiffening of graphene under low dose irradiation, as well as paths to tailor the mechanical properties of this material via applied strain and irradiation.This work is supported by the Generalitat Valenciana through grant reference PROMETEO2012/011 and the Spanish government through grant FIS2010-21883. CJR and EMB thanks support from SeCTyP-UNCuyo grant M003, and ANPCyT grant PICT-2014-0696. CJR thanks CONICET and the 310 Group at FCEN-UNCuyo
Local electroexfoliation of graphene with a STM tip
Graphite surfaces can be manipulated by several methods to create graphene structures of different shapes and sizes. Scanning tunneling microscopy (STM) can be used to create these structures either through mechanical contact between the tip and the surface or through electro-exfoliation. In the latter, the mechanisms involved in the process of exfoliation with an applied voltage are not fully understood. Here we show how a graphite surface can be locally exfoliated in a systematic manner by applying an electrostatic force with a STM tip at the edge of a terrace, forming triangular flakes several nanometers in length. We demonstrate, through experiments and simulations, how these flakes are created by a two-step process: first a voltage ramp must be applied at the edge of the terrace, and then the tip must be scanned perpendicularly to the edge. Ab-initio electrostatic calculations reveal that the presence of charges on the graphite surface weakens the interaction between layers allowing for exfoliation at voltages in the same range as those used experimentally. Molecular dynamics simulations show that a force applied locally on the edge of a step produces triangular flakes such as those observed under STM. Our results provide new insights towards surface modification that can be extended to other layered materials
Coronavirus Optimization Algorithm: A Bioinspired Metaheuristic Based on the COVID-19 Propagation Model
This study proposes a novel bioinspired metaheuristic simulating how the coronavirus spreads and infects healthy people. From a primary infected individual (patient zero), the coronavirus rapidly infects new victims, creating large populations of infected people who will either die or spread infection. Relevant terms such as reinfection probability, super-spreading rate, social distancing measures, or traveling rate are introduced into the model to simulate the coronavirus activity as accurately as possible. The infected population initially grows exponentially over time, but taking into consideration social isolation measures, the mortality rate, and number of recoveries, the infected population gradually decreases. The coronavirus optimization algorithm has two major advantages when compared with other similar strategies. First, the input parameters are already set according to the disease statistics, preventing researchers from initializing them with arbitrary values. Second, the approach has the ability to end after several iterations, without setting this value either. Furthermore, a parallel multivirus version is proposed, where several coronavirus strains evolve over time and explore wider search space areas in less iterations. Finally, the metaheuristic has been combined with deep learning models, to find optimal hyperparameters during the training phase. As application case, the problem of electricity load time series forecasting has been addressed, showing quite remarkable performance.Ministerio de Economía y Competitividad TIN2017-88209-C
Fruit and Vegetable Consumption is Inversely Associated with Plasma Saturated Fatty Acids at Baseline in Predimed Plus Trial
I.D.-L. is supported by the [FI_B 00256] from the FI-AGAUR Research Fellowship Program, Generalitat de Catalunya and M.M.-M is supported by the FPU17/00513 grant. a.-H. is supported by the [CD17/00122] grant and S.K.N. is supported by a Canadian Institutes of Health Research (CIHR) Fellowship. We also thank all the volunteers for their participation in and the personnel for their contribution to the PREDIMED-Plus trial. This research was funded by CiCYT [AGL2016-75329-R] and CIBEROBN from the Instituto de Salud Carlos III, ISCIII from the Ministerio de Ciencia, Innovacion y Universidades, (AEI/FEDER, UE), Generalitat de Catalunya (GC) [2017SGR196]. The PREDIMED-Plus trial was supported by the official Spanish Institutions for funding scientific biomedical research, CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn) and Instituto de Salud Carlos III (ISCIII), through the Fondo de Investigacion para la Salud (FIS), which is co-funded by the European Regional Development Fund (four coordinated Fondo de Investigaciones Sanitarias projects lead by J.S.-S. and J.V., including the following projects: PI13/00673, PI13/00492, PI13/00272, PI13/01123, PI13/00462, PI13/00233, PI13/02184, PI13/00728, PI13/01090, PI13/01056, PI14/01722, PI14/00636, PI14/00618, PI14/00696, PI14/01206, PI14/01919, PI14/00853, PI14/01374, PI14/00972, PI14/00728, PI14/01471, PI16/00473, PI16/00662, PI16/01873, PI16/01094, PI16/00501, PI16/00533, PI16/00381, PI16/00366, PI16/01522, PI16/01120, PI17/00764, PI17/01183, PI17/00855, PI17/01347, PI17/00525, PI17/01827, PI17/00532, PI17/00215, PI17/01441, PI17/00508, PI17/01732, PI17/00926 and PI19/00781), the Especial Action Project entitled Implementacion y evaluacion de una intervencion intensiva sobre la actividad fisica Cohorte PREDIMED-Plus grant to J.S.-S., European Research Council (Advanced Research Grant 2014-2019, 340918) to M.a.M.-G., the Recercaixa grant to J.S.-S. (2013ACUP00194), grants from the Consejeria de Salud de la Junta de Andalucia (PI0458/2013, PS0358/2016, and PI0137/2018), a grant from the Generalitat Valenciana (PROMETEO/2017/017), a SEMERGEN grant, Fundacio la Marato de TV3 (PI044003), 2017 SGR 1717 from Generalitat de Catalunya, a CICYT grant provided by the Ministerio de Ciencia, Innovacion y Universidades (AGL2016-75329-R), and funds from the European Regional Development Fund (CB06/03 and CB12/03). Food companies Hojiblanca (Lucena, Spain) and Patrimonio Comunal Olivarero (Madrid, Spain) donated extra virgin olive oil, and the Almond Board of California (Modesto, CA, USA), American Pistachio Growers (Fresno, CA, USA), and Paramount Farms (Wonderful Company, LLC, Los Angeles, CA, USA) donated nuts. J.K. was supported by the "FOLIUM" program within the FUTURMed project entitled Talent for the medicine within the future from the Fundacio Institut d'Investigacio Sanitaria Illes Balears. This call was co-financed at 50% with charge to the Operational Program FSE 2014-2020 of the Balearic Islands. This work is partially supported by ICREA under the ICREA Academia programme to J.S.-S.Scope: Plasma fatty acids (FAs) are associated with the development of cardiovascular diseases and metabolic syndrome.
The aim of our study is to assess the relationship between fruit and vegetable (F&V) consumption and plasma FAs and
their subtypes.
Methods and Results: Plasma FAs are assessed in a cross-sectional analysis of a subsample of 240 subjects from the
PREDIMED-Plus study. Participants are categorized into four groups of fruit, vegetable, and fat intake according to the
food frequency questionnaire. Plasma FA analysis is performed using gas chromatography. Associations between FAs
and F&V consumption are adjusted for age, sex, physical activity, bodymass index (BMI), total energy intake, and alcohol
consumption. Plasma saturated FAs are lower in groups with high F&V consumption (-1.20 mg cL−1 [95% CI: [-2.22, -
0.18], p-value = 0.021), especially when fat intake is high (-1.74 mg cL−1 [95% CI: [-3.41, -0.06], p-value = 0.042). Total
FAs and n-6 polyunsaturated FAs tend to be lower in high consumers of F&V only in the high-fat intake groups.
Conclusions: F&V consumption is associated with lower plasma saturated FAs when fat intake is high. These findings
suggest that F&V consumption may have different associations with plasma FAs depending on their subtype and on the
extent of fat intake.Generalitat de Catalunya FI_B 00256Canadian Institutes of Health Research (CIHR)Consejo Interinstitucional de Ciencia y Tecnologia (CICYT)European Commission AGL2016-75329-RCIBEROBN from the Instituto de Salud Carlos III
ISCIII from the Ministerio de Ciencia, Innovacion y Universidades, (AEI/FEDER, UE)Generalitat de Catalunya 2017SGR196CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn)Instituto de Salud Carlos III (ISCIII), through the Fondo de Investigacion para la Salud (FIS)European Commission PI13/00673
PI13/00492
PI13/00272
PI13/01123
PI13/00462
PI13/00233
PI13/02184
PI13/00728
PI13/01090
PI13/01056
PI14/01722
PI14/00636
PI14/00618
PI14/00696
PI14/01206
PI14/01919
PI14/00853
PI14/01374Especial Action Project entitled Implementacion y evaluacion de una intervencion intensiva sobre la actividad fisica Cohorte PREDIMED-Plus grantEuropean Research Council (ERC)
European Commission 340918Recercaixa grant 2013ACUP00194Junta de Andalucia PI0458/2013
PS0358/2016
PI0137/2018Generalitat Valenciana
European Commission PROMETEO/2017/017SEMERGEN grant, Fundacio la Marato de TV3 PI044003Generalitat de Catalunya 2017 SGR 1717Ministerio de Ciencia, Innovacion y Universidades AGL2016-75329-R"FOLIUM" program within the FUTURMed project within Fundacio Institut d'Investigacio Sanitaria Illes BalearsICREA under the ICREA Academia programmeThe European Regional Development Fund PI17/01347
PI17/00525
PI17/01827
PI17/00532
PI17/00215
PI17/01441
PI17/00508
PI17/01732
PI17/00926
PI19/00781
CB06/03
CB12/03European Commission PI14/00972
PI14/00728
PI14/01471
PI16/00473
PI16/00662
PI16/01873
PI16/01094
PI16/00501
PI16/00533
PI16/00381
PI16/00366
PI16/01522
PI16/01120
PI17/00764
PI17/01183
PI17/00855
FPU17/00513
CD17/0012
Longitudinal association of dietary acid load with kidney function decline in an older adult population with metabolic syndrome
Background: Diets high in acid load may contribute to kidney function impairment. This study aimed to investigate the association between dietary acid load and 1-year changes in glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (UACR). Methods: Older adults with overweight/obesity and metabolic syndrome (mean age 65 ± 5 years, 48% women) from the PREDIMED-Plus study who had available data on eGFR (n = 5,874) or UACR (n = 3,639) at baseline and after 1 year of follow-up were included in this prospective analysis. Dietary acid load was estimated as potential renal acid load (PRAL) and net endogenous acid production (NEAP) at baseline from a food frequency questionnaire. Linear and logistic regression models were fitted to evaluate the associations between baseline tertiles of dietary acid load and kidney function outcomes. One year-changes in eGFR and UACR were set as the primary outcomes. We secondarily assessed ≥ 10% eGFR decline or ≥10% UACR increase. Results: After multiple adjustments, individuals in the highest tertile of PRAL or NEAP showed higher one-year changes in eGFR (PRAL, β: –0.64 ml/min/1.73 m2; 95% CI: –1.21 to –0.08 and NEAP, β: –0.56 ml/min/1.73 m2; 95% CI: –1.13 to 0.01) compared to those in the lowest category. No associations with changes in UACR were found. Participants with higher levels of PRAL and NEAP had significantly higher odds of developing ≥10% eGFR decline (PRAL, OR: 1.28; 95% CI: 1.07–1.54 and NEAP, OR: 1.24; 95% CI: 1.03–1.50) and ≥10 % UACR increase (PRAL, OR: 1.23; 95% CI: 1.04–1.46) compared to individuals with lower dietary acid load. Conclusions: Higher PRAL and NEAP were associated with worse kidney function after 1 year of follow-up as measured by eGFR and UACR markers in an older Spanish population with overweight/obesity and metabolic syndrome
Longitudinal association of dietary acid load with kidney function decline in an older adult population with metabolic syndrome
Background: Diets high in acid load may contribute to kidney function impairment. This study aimed to investigate the association between dietary acid load and 1-year changes in glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (UACR). Methods: Older adults with overweight/obesity and metabolic syndrome (mean age 65 ± 5 years, 48% women) from the PREDIMED-Plus study who had available data on eGFR (n = 5,874) or UACR (n = 3,639) at baseline and after 1 year of follow-up were included in this prospective analysis. Dietary acid load was estimated as potential renal acid load (PRAL) and net endogenous acid production (NEAP) at baseline from a food frequency questionnaire. Linear and logistic regression models were fitted to evaluate the associations between baseline tertiles of dietary acid load and kidney function outcomes. One year-changes in eGFR and UACR were set as the primary outcomes. We secondarily assessed ≥ 10% eGFR decline or ≥10% UACR increase. Results: After multiple adjustments, individuals in the highest tertile of PRAL or NEAP showed higher one-year changes in eGFR (PRAL, β: -0.64 ml/min/1.73 m2; 95% CI: -1.21 to -0.08 and NEAP, β: -0.56 ml/min/1.73 m2; 95% CI: -1.13 to 0.01) compared to those in the lowest category. No associations with changes in UACR were found. Participants with higher levels of PRAL and NEAP had significantly higher odds of developing ≥10% eGFR decline (PRAL, OR: 1.28; 95% CI: 1.07-1.54 and NEAP, OR: 1.24; 95% CI: 1.03-1.50) and ≥10 % UACR increase (PRAL, OR: 1.23; 95% CI: 1.04-1.46) compared to individuals with lower dietary acid load. Conclusions: Higher PRAL and NEAP were associated with worse kidney function after 1 year of follow-up as measured by eGFR and UACR markers in an older Spanish population with overweight/obesity and metabolic syndrome. Keywords: albuminuria; chronic kidney disease (CKD); dietary acid load; glomerular filtration rate (GFR); kidney function; net endogenous acid production (NEAP); potential renal acid load (PRAL); renal nutrition
Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry
Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase