Three-dimensional multifractal analysis of trabecular bone under clinical computed tomography

Purpose: An adequate understanding of bone structural properties is critical for predicting fragility conditions caused by diseases such as osteoporosis, and in gauging the success of fracture prevention treatments. In this work we aim to develop multiresolution image analysis techniques to extrapolate high-resolution images predictive power to images taken in clinical conditions. Methods: We performed multifractal analysis (MFA) on a set of 17 ex vivo human vertebrae clinical CT scans. The vertebræ failure loads (FFailure) were experimentally measured. We combined bone mineral density (BMD) with different multifractal dimensions, and BMD with multiresolution statistics (e.g., skewness, kurtosis) of MFA curves, to obtain linear models to predict FFailure. Furthermore we obtained short- and long-term precisions from simulated in vivo scans, using a clinical CT scanner. Ground-truth data - high-resolution images - were obtained with a High-Resolution Peripheral Quantitative Computed Tomography (HRpQCT) scanner. Results: At the same level of detail, BMD combined with traditional multifractal descriptors (Lipschitz-Hölder exponents), and BMD with monofractal features showed similar prediction powers in predicting FFailure (87%, adj. R2). However, at different levels of details, the prediction power of BMD with multifractal features raises to 92% (adj. R2) of FFailure. Our main finding is that a simpler but slightly less accurate model, combining BMD and the skewness of the resulting multifractal curves, predicts 90% (adj. R2) of FFailure. Conclusions: Compared to monofractal and standard bone measures, multifractal analysis captured key insights in the conditions leading to FFailure. Instead of raw multifractal descriptors, the statistics of multifractal curves can be used in several other contexts, facilitating further research.Fil: Baravalle, Rodrigo Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y de Sistemas. Universidad Nacional de Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y de Sistemas; ArgentinaFil: Thomsen, Felix Sebastian Leo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; ArgentinaFil: Delrieux, Claudio Augusto. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lu, Yongtao. Dalian University of Technology; ChinaFil: Gómez, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y de Sistemas. Universidad Nacional de Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y de Sistemas; ArgentinaFil: Stošić, Borko. Universidade Federal Rural Pernambuco; BrasilFil: Stošić, Tatijana. Universidade Federal Rural Pernambuco; Brasi

Porous Graphitic Carbons Containing Nitrogen by Structuration of Chitosan with Pluronic P123

[EN] Using Pluronic P123 as a structure-directing agent and chitosan as a carbon precursor, different porous carbons with remarkable morphologies such as orthohedra or spheres with diametrically opposite holes are obtained. These particles of micrometric size are constituted by the stacking of thin sheets (60 nm) that become increasingly bent in the opposite sense, concave in the upper and convex in the bottom hemispheres, as the chitosan proportion increases. TEM images, after dispersion of the particles by sonication, show that besides micrometric graphene sheets, the material is constituted by nanometric onion-like carbons. The morphology and structure of these porous carbons can be explained based on the ability of Pluronic P123 to undergo self-assembly in aqueous solution due to its amphoteric nature and the filmogenic properties of chitosan to coat Pluronic P123 nanoobjects undergoing structuration and becoming transformed into nitrogen-doped graphitic carbons. XPS analysis reveals the presence of nitrogen in their composition. These porous carbons exhibit a significant CO2 adsorption capacity of above 3 mmol g(-1) under 100 kPa at 273 K attributable to their large specific surface area, ultraporosity, and the presence of basic N sites. In addition, the presence of dopant elements in the graphitic carbons opening the gap is responsible for the photocatalytic activity for H-2 generation in the presence of sacrificial electron donors, reaching a H-2 production of 63 mu mol g(-1) in 24 h.The Spanish Ministry of Science, Innovation and Universities (Severo Ochoa and RTI2018-89237-CO2-R1) and Generalitat Valenciana (Prometeo 2017/083).Peng, L.; Peng, Y.; Primo Arnau, AM.; García Gómez, H. (2021). Porous Graphitic Carbons Containing Nitrogen by Structuration of Chitosan with Pluronic P123. ACS Applied Materials & Interfaces. 13(11):13499-13507. https://doi.org/10.1021/acsami.0c19463S1349913507131

Multispectral images of peach related to firmness and maturity at harvest

wo multispectral maturity classifications for red soft-flesh peaches (‘Kingcrest’, ‘Rubyrich’ and ‘Richlady’ n = 260) are proposed and compared based on R (red) and R/IR (red divided by infrared) images obtained with a three CCD camera (800 nm, 675 nm and 450 nm). R/IR histograms were able to correct the effect of 3D shape on light reflectance and thus more Gaussian histograms were produced than R images. As fruits ripened, the R/IR histograms showed increasing levels of intensity. Reference measurements such as firmness and visible spectra also varied significantly as the fruit ripens, firmness decreased while reflectance at 680 nm increased (chlorophyll absorption peak)

Norm violation versus punishment risk in a social model of corruption

We analyze the onset of social-norm-violating behaviors when social punishment is present. To this aim, a compartmental model is introduced to illustrate the flows among the three possible states: Honest, corrupt, and ostracism. With this simple model we attempt to capture some essential ingredients such as the contagion of corrupt behaviors to honest agents, the delation of corrupt individuals by honest ones, and the warning to wrongdoers (fear like that triggers the conversion of corrupt people into honesty). In nonequilibrium statistical physics terms, the former dynamics can be viewed as a non-Hamiltonian kinetic spin-1 Ising model. After developing in full detail its mean-field theory and comparing its predictions with simulations made on regular networks, we derive the conditions for the emergence of corrupt behaviors and, more importantly, illustrate the key role of the warning-to-wrongdoers mechanism in the latter

Structural characterization of HPM-7, a more ordered than expected germanosilicate zeolite

HPM-7, a germanosilicate synthesized using long imidazolium-based dications with two different linkers, is shown to possess the POS topology, although disorder may exist but it is very difficult to discern. First, three simple ordered polymorphs (POS-A to POS-C) with very similar energies and structural motifs could give rise to intergrowths that would be very difficult to recognize by powder X-ray diffraction, according to DIFFaX simulations. Another four structures (POS-D to POS-G) can be derived from POS by changing the orientation of two single four rings within the structure, possibly providing an additional source of disorder. While 3D EDT strongly suggests that HPM-7 basically possesses the POS-A (i.e. POS) topology, a detailed HR-STEM study demonstrates the rare existence of some disorder compatible with the polymorph POS-D. The general avoidance of polymorphs with very similar structural motifs and comparable energies points to a rather specific structure-direction by the organic dications used

Tridimensional N, P-Codoped Carbon Sponges as Highly Selective Catalysts for Aerobic Oxidative Coupling of Benzylamine

[EN] Two tridimensional N-doped porous carbon sponges (3DC-X) have been prepared by using cetyltrimethylammonium chloride ( CTAC) and cetyltrimethylammonium bromide (CTAB) as soft templates and alginate to replicate the liquid crystals formed by CTA+ in water. Alginate is a filmogenic polysaccharide of natural origin having the ability to form nanometric defectless films around objects. Subsequent pyrolysis at 900 degrees C under an Ar flow of the resulting CTA(+)-polysaccharide assemblies result in 3DC-1 and 3DC-2, with the N percentages of 0.48 and 0.36 wt % for the materials resulting from CTAC and CTAB, respectively. Another four 3DC materials were obtained via pyrolysis of the adduct of phytic acid and chitosan, rendering an amorphous, N and P-codoped carbon sample (3DC-3 to 3DC-6). The six 3DC samples exhibit a large area (>650 m(2) x g(-1)) and porosity, as determined by Ar adsorption. The catalytic activity of these materials in promoting the aerobic oxidation of benzylamine increases with the specific surface area and doping, being the largest for 3DC-4, which is able to achieve 73% benzylamine conversion to N-benzylidene benzylamine in solventless conditions at 70 degrees C in 5 h. Quenching studies and hot filtration tests indicate that 3DC-4 acts as a heterogeneous catalyst rather than an initiator, triggering the formation of hydroperoxyl and hydroxyl radicals as the main reactive oxygen species involved in the aerobic oxidation.Financial support by the Spanish Ministry of Science and Innovation (Severo Ochoa 2016 and RTI2018-890237-CO2-R1) and Generalitat Valenciana is gratefully acknowledged. A.P. thanks the Spanish Ministry for a Ramon y Cajal Research associate contract. A.D. is thankful to the University Grants Commission, New Dekhi, for awarding Assistant Professorship through the Faculty Recharge Programme.Peng, L.; Garcia-Baldovi, H.; Dhakshinamoorthy, A.; Primo Arnau, AM.; García Gómez, H. (2022). Tridimensional N, P-Codoped Carbon Sponges as Highly Selective Catalysts for Aerobic Oxidative Coupling of Benzylamine. ACS Omega. 7(13):11092-11100. https://doi.org/10.1021/acsomega.1c07179110921110071

ZnCdS Dotted with Highly Dispersed Pt Supported on SiO2 Nanospheres Promoting Photocatalytic Hydrogen Evolution

[EN] The efficiency of solar hydrogen evolution closely depends on the fast transfer of charge carriers and the effective use of visible light. In this work, a novel photocatalyst SiO2/ZnCdS/Pt was successfully prepared to solve these two problems. An artistic structure of the photocatalyst was constructed and ZnCdS was successfully wrapped on the surface of SiO2 spheres with uniform Pt nanoparticles (NPs) in a size of 4.1 +/- 0.7 nm highly dispersed on the ZnCdS shell through the self-assembly method. Pt NPs can absorb the scattered light in the near field of SiO2 spheres. With the synergistic effect of SiO2 spheres and small highly dispersed Pt NPs, the absorption of visible light was significantly promoted. Meanwhile, the electron-hole recombination was also effectively inhibited, thus improving the photocatalytic activity. The hydrogen production activity of the highly efficient photocatalyst was as high as 8.3 mmol g(-1) h(-1) under visible light (lambda > 420 nm). The photocatalytic activity of SiO2/ZnCdS/Pt was 2.9 times higher than that of the ZnCdS/Pt photocatalyst.This work was supported by the National Natural Science Foundation of China (21976111), Shandong Provincial Natural Science Foundation (ZR2019MB052), and Large Instrument Open Foundation of Shandong Normal University (KFJJ2019004; KFJJ2021006).Liu, K.; Peng, L.; Zhen, P.; Chen, L.; Song, S.; García Gómez, H.; Sun, C. (2021). ZnCdS Dotted with Highly Dispersed Pt Supported on SiO2 Nanospheres Promoting Photocatalytic Hydrogen Evolution. The Journal of Physical Chemistry C. 125(27):14656-14665. https://doi.org/10.1021/acs.jpcc.1c0353514656146651252

Electric Car Purchase Price as a Factor Determining Consumers’ Choice and their Views on Incentives in Europe

The deployment of zero-emission vehicles has the potential to drastically reduce air pollution and greenhouse gas emissions from road transport. The purpose of this study is to provide evidence on, and quantify the factors that influence, the European market for electric and fuel cell car technologies. The paper reports the results of a stated preference survey among 1,248 car owners in France, Germany, Italy, Poland, Spain and the United Kingdom. The variables that influence powertrain choice are quantified in a nested multinomial logit model. We find that the electric car purchase price continues to be a major deterrent to sales in the surveyed countries. The majority of the respondents considered government incentives as fundamental or important for considering an electric car purchase. Because of the differences in the socio-economic characteristics of consumers in each country, the effectiveness of government incentives may vary across Europe

Co-Fe Nanoparticles Wrapped on N-Doped Graphitic Carbons as Highly Selective CO2 Methanation Catalysts

[EN] Pyrolysis of chitosan containing various loadings of Co and Fe renders Co-Fe alloy nanoparticles supported on N-doped graphitic carbon. Transmission electron microscopy (TEM) images show that the surface of Co-Fe NPs is partially covered by three or four graphene layers. These Co-Fe@(N)C samples catalyze the Sabatier CO2 hydrogenation, increasing the activity and CH4 selectivity with the reaction temperature in the range of 300-500 degrees C. Under optimal conditions, a CH4 selectivity of 91% at an 87% CO2 conversion was reached at 500 degrees C and a space velocity of 75 h(-1) under 10 bar. The Co-Fe alloy nanoparticles supported on N-doped graphitic carbon are remarkably stable and behave differently as an analogous Co-Fe catalyst supported on TiO2.Financial support by the Spanish Ministry of Science, Innovation and University (Severo Ochoa and RTI2018.98237-B-CO1) and Generalitat Valenciana (Prometeo 2017/083) is gratefully acknowledged. L.P. thanks the Generalitat Valenciana for a Santiago Grisolia scholarship, and A.P. thanks the Spanish Ministry of Science and Education for a Ramon y Cajal research associate contract. V.I.P. thanks the UEFISCDI for continued funding through the projects PN-IIIP1-1.2-PCCDI-2017-0541 1/2018, PN-III-P4-ID-PCCF-20160088 17/2021, and PN-III-P4-ID-PCE-2020-1532. BASF is thanked for the financial support.Jurca, B.; Peng, L.; Primo Arnau, AM.; Gordillo, A.; Parvulescu, VI.; García Gómez, H. (2021). Co-Fe Nanoparticles Wrapped on N-Doped Graphitic Carbons as Highly Selective CO2 Methanation Catalysts. ACS Applied Materials & Interfaces. 13(31):36976-36981. https://doi.org/10.1021/acsami.1c055423697636981133

Co-Fe Clusters Supported on N-Doped Graphitic Carbon as Highly Selective Catalysts for Reverse Water Gas Shift Reaction

This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Sustainable Chemistry & Engineering, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acssuschemeng.1c01401[EN] Graphitic carbons are suitable supports of metal nanoparticles with catalytic activity. In the present study, the preparation of N-doped graphitic carbon supporting clusters of Fe-Co alloys starting from biomass waste is reported. These sub-nanometric Co-Fe clusters supported on N-doped graphitic carbon at a metal loading below 0.2 wt % exhibit high activity for the selective hydrogenation of CO2 to CO. Operating at 500 degrees C and 10 bar with an H-2/CO2 molar ratio of 7 and a space velocity of 600 h(-1), a conversion of 56% with a selectivity of over 98% to CO, and remarkable stability over 30 h operation was obtained. Interestingly, analogous catalysts based on N-doped graphitic carbon with much higher Co-Fe loadings and an average particle size range of 1-5 nm exhibit only half of this activity, with similar CO selectivity. This contrasting behavior reveals the dramatic effect of the particle size on the catalytic activity. In comparison, SiO2 as support under similar conditions affords CH4 as the main product.Financial support by the Spanish Ministry of Science, Innovation, and University (Severo Ochoa and RTI2018.98237-B-CO1) and Generalitat Valenciana (Prometeo 2017/083) is gratefully acknowledged. L.P. thanks the Generalitat Valenciana for a Santiago Grisolia scholarship. BASF is thanked for financial support.Peng, L.; Jurca, B.; Primo Arnau, AM.; Gordillo, A.; Parvulescu, VI.; García Gómez, H. (2021). Co-Fe Clusters Supported on N-Doped Graphitic Carbon as Highly Selective Catalysts for Reverse Water Gas Shift Reaction. ACS Sustainable Chemistry & Engineering. 9(28):9264-9272. https://doi.org/10.1021/acssuschemeng.1c014019264927292