| Francesca Stazi, Nicola Pierandrei, Costanzo Di Perna, Francesca Tittarelli, “Experimental evaluation of natural hydraulic lime renders with nanoclay and nanolime to protect raw earth building surfaces”, Case Studies in Construction Materials, Volume 17, December 2022, e01564. |
| Abstract: In this study Natural Hydraulic Lime (NHL) was combined with clay and lime, the main cementitious materials used in ancient buildings, to develop a new render more suitable for applications on raw earth substrates. Nanoclay and nanolime have been separately added to a commercial NHL-based ready-mixed powder. Pure and nano-additivated NHL renders have been compared in terms of microstructure (by SEM and mercury porosimetry), mechanical performance (by dynamic elastic modulus, flexural and compressive strength tests), adhesion to the substrate (by shear strength and pull-off tests), erosion resistance (by pressure spray test), and thermo-hygrometric performance (by water absorption and thermal conductivity tests). The obtained results demonstrate that both nanoparticles increase the water absorption and decrease the mechanical properties of the render but enhance the adhesion with the earthen support and the protection against water erosion. Among the two nanoparticles, the addition of nanoclay was found to be preferable since it gives to the render the highest mechanical compatibility with the underlying layer and the best durability against erosion. |
| Marco Mandolini, Agnese Brunzini, Giulia Facco, Alida Mazzoli, Archimede Forcellese, Antonio Gigante “Comparison of Three 3D Segmentation Software Tools for Hip Surgical Planning”, Sensors 2022, 22, 5242. https://doi.org/10.3390/s22145242. |
| Abstract: In hip arthroplasty, preoperative planning is fundamental to reaching a successful surgery. Nowadays, several software tools for computed tomography (CT) image processing are available. However, research studies comparing segmentation tools for hip surgery planning for patients affected by osteoarthritic diseases or osteoporotic fractures are still lacking. The present work compares three different software from the geometric, dimensional, and usability perspectives to identify the best three-dimensional (3D) modelling tool for the reconstruction of pathological femoral heads. Syngo.via Frontier (by Siemens Healthcare) is a medical image reading and post-processing software that allows low-skilled operators to produce prototypes. Materialise (by Mimics) is a commercial medical modelling software. 3D Slicer (by slicer.org) is an open-source development platform used in medical and biomedical fields. The 3D models reconstructed starting from the in vivo CT images of the pathological femoral head are compared with the geometries obtained from the laser scan of the in vitro bony specimens. The results show that Mimics and 3D Slicer are better for dimensional and geometric accuracy in the 3D reconstruction, while syngo.via Frontier is the easiest to use in the hospital setting. |
| Marco Mandolini, Agnese Brunzini, Manila Caragiuli, Alida Mazzoli, Mario Pagnoni “An innovative orbital implant positioner for the proper restoration of eye-socket defects”. Bio- Design and Manufacturing, November 2022. https://doi.org/10.1007/s42242-022-00217-z |
| Abstract: In hip arthroplasty, preoperative planning is fundamental to reaching a successful surgery. Fractures to the orbital walls and floor must be appropriately managed to avoid severe conditions. This results in particularly challenging anatomical reconstructions. The main issues are the implant’s proper shaping, placement, and orientation onto the eye socket. A new, customized implant-shaping mould has already been developed to shape patient-specific implants. However, it still does not address the implant positioning in the fractured orbital cavity. This present research aims to design, develop, and assess an innovative implant positioner to be used with the optimized version of the aforementioned implant-shaping mould. The new medical device was designed to be used with titanium meshes and deantigenated bone implants. It is easy to use, has a low cost, and is reusable several times. It is composed of (1) two coupled and hinged handles that allow the grasping of the implant, and (2) the positioner itself that permits proper implant placement and orientation. Selective laser sintering was used to print the mould and the new device in polyamide. Promising results for implant shaping, positioning, and orientation accuracy were obtained. An accuracy of 0.1 mm and 1.3 mm was, respectively, achieved for the implant shape and its placement in the mediolateral direction. The mean malrotation angle around the orbital rim was about 6°. |
| L. Alessandrino, A.L. Eusebi, V. Aschonitis, M. Mastrocicco, N. Colombani, Variation of the hydraulic properties in sandy soils induced by the addition of graphene and classical soil improvers, Journal of Hydrology 612, 128256, 2022 |
| Abstract: In this study, for the first time, the changes in relevant hydraulic parameters (e.g., hydraulic conductivity, effective porosity, and dispersivity) induced by the introduction of graphene in a calcareous sandy soil and a siliciclastic riverine soil were monitored and modelled via leaching column experiments. Column experiments were also run with traditional soil improvers (compost, biochar, and zeolite) to compare the changes induced by graphene versus well-studied soil improvers. Constant pressure head tests were used to calculate the hydraulic conductivity of each column, while leaching experiments were run to estimate porosity and specific retention, and for each treatment three replicates were done. Columns were then run in saturated conditions via a low flow peristaltic pump and monitored for electrical conductivity, temperature, and chloride. CXTFIT 2.0 was employed to inversely model the column experiments and retrieve parameters like effective porosity, longitudinal dispersivity, bulk thermal diffusivity, and thermal retardation factor. Results highlighted small changes of hydraulic conductivity, porosity, and effective porosity induced by graphene addition (as well as by the other soil improvers) for both soils. A marked increase (nearly 20 %) of specific retention values was instead recorded in the amended columns with respect to control ones. Chloride breakthrough curves modelling showed that graphene doubled dispersivity in the calcareous sandy soil (5.82±1.4 cm) compared to the control (2.6±0.29 cm), while it halved dispersivity in the siliciclastic riverine soil (0.31 ± 0.05 cm) with respect to the control (0.65±0.06 cm). Thermal retardation factors were decreased by graphene by approximately 20% for both soils. The model fitting via TDS (derived from the electrical conductivity monitoring) produced unreliable dispersivity values in most of the experiments due to the nonconservative nature of this parameter compared to chloride. The results highlight that graphene affected dispersivity but did not significantly alter other physical parameters relevant for solutes transport in sandy soils in comparison to classical improvers, thus future studies should focus on the graphene’s effects on nutrients and agrochemicals leaching in unsaturated flow conditions. |
| M. Gaiolini, N. Colombani, G. Busico, F. Rama, M. Mastrocicco, Impact of Boundary Conditions Dynamics on Groundwater Budget in the Campania Region (Italy), Water 14(16), 2462, 2022 |
| Abstract: Groundwater budgets and fluxes are affected by human activities and climate change. Numerical models are cost-effective tools to investigate the different components of the hydrologic cycle. In this study, a groundwater flow model of the unconfined aquifers of the Campania region (Italy) has been developed and calibrated in Processing Modflow 11, resulting in an accurate assessment of groundwater fluxes and their trends over fifteen years (2000–2015). The model was implemented using a high-resolution grid to capture small hydrogeological features such as wells and rivers and informed by time variable datasets used as boundary conditions (i.e., river and sea levels, aquifer recharge, evapotranspiration, and discharge from adjacent systems). Good calibration and validation performances were achieved for piezometric heads (R2 = 0.958). A set of scenarios was developed using constant boundary conditions (i.e., constant sea-level BC, uniform extinction depth BC), and the outputs were compared, quantitively assessing differences in groundwater fluxes. Simulations pointed out that using time series to inform boundary conditions in the model does not always result in a significant change in the computed fluxes. Overall, non-uniform extinction depth was the most influential condition, while both rivers and sea level conditions barely affected groundwater budgets. In addition, results highlighted the need for an accurate estimation of spatiotemporal variations of both recharge and evapotranspiration, due to their strong seasonal variability and their massive contribution to the hydrogeological cycle. Finally, a marked increase of evapotranspiration fluxes controlled by interannual variability of precipitation and atmospheric temperatures has been quantified over the modelled period. |
| E. Soana, F. Vincenzi, N. Colombani, M. Mastrocicco, E.A. Fano, G. Castaldelli, Soil Denitrification, the Missing Piece in the Puzzle of Nitrogen Budget in Lowland Agricultural Basins, Ecosystems 25, 633–647, 2022 |
| Abstract: Denitrification is a key process buffering the environmental impacts of agricultural nitrate loads but, at present, remains the least understood and poorly quantified sink in nitrogen budgets at the watershed scale. The present work deals with a comprehensive and detailed analysis of nitrogen sources and sinks in the Burana–Volano–Navigabile basin, the southernmost portion of the Po River valley (Northern Italy), an intensively cultivated (> 85% of basin surface) low-lying landscape. Agricultural census data, extensive monitoring of surface–groundwater interactions, and laboratory experiments targeting N fluxes and pools were combined to provide reliable estimates of soil denitrification at the basin scale. In the agricultural soils of the basin, nitrogen inputs exceeded outputs by nearly 40% (~ 80 kg N ha−1 year−1), but this condition of potential N excess did not translate into widespread nitrate pollution. The general scarcity of inorganic nitrogen species in groundwater and soils indicated limited leakage and storage. Multiple pieces of evidence supported that soil denitrification was the process that needed to be introduced in the budget to explain the fate of the missing nitrogen. Denitrification was likely boosted in the soils of the studied basin, prone to waterlogged conditions and consequently oxygen-limited, owing to peculiar features such as fine texture, low hydraulic conductivity, and shallow water table. The present study highlighted the substantial contribution of soil denitrification to balancing nitrogen inputs and outputs in agricultural lowland basins, a paramount ecosystem function preventing eutrophication phenomena. |
| M. Pierpaoli, P. Jakóbczyk, B. Dec, C. Giosuè, N. Czerwińska, A. Lewkowicz, M.L. Ruello, R. Bogdanowicz, A novel hierarchically-porous diamondized polyacrylonitrile sponge-like electrodes for acetaminophen electrochemical detection, Electrochimica Act 430 (2022): 141083. |
| Abstract: A novel composite electrode material consisting of tangled fibrous polyacrylonitrile-based hierarchically-structured nanocomposites has been produced by wet-spinning, carbonized and decorated with a carbon nanoarchitecture by microwave plasma-enhanced chemical vapor deposition and investigated as a metal-free electrode for the enhanced electrochemical detection of acetaminophen. Surprisingly, the hierarchical fiber architecture is the result of the synergistic action between surface etching, by the H2 plasma, and nanostructure formation, by the C- and CH- radicals, which significantly affect the porosity and electrochemical performance. Moreover, by simultaneously conducting fiber carbonization and surface functionalization, it is possible to dramatically reduce the manufacturing time and to confer an 18-fold increase of the acetaminophen detection sensitivity, due to the sp2-C defect-rich overgrown nanostructure, which represents a preferable site for the drug adsorption, as supported by the molecular dynamics simulation results. Because of the excellent performance, and the simple and scalable production method, the prepared composite is a promising candidate as a metal-free electrochemical sensor. |
| Serrani, D., Cocco, S., Cardelli, V., D’Ottavio, P., Borguete, A.R.R., Feniasse, D., Vilanculos, A., Fernández-Marcos, M.L., Giosué, C., Tittarelli, F. and Corti, G., 2022. Soil fertility in slash and burn agricultural systems in central Mozambique. Journal of Environmental Management, 322, p.116031. |
| Slash and burn is a land use practice widespread all over the world, and nowadays it is formally recognized as the principal livelihood system in rural areas of South America, Asia, and Africa. The practice consists of a land rotation where users cut native or secondary forest to establish a new crop field and, in some cases, build charcoal kilns with the cut wood to produce charcoal. Due to several socio-economic changes in developing countries, some scientists and international organizations have questioned the sustainability of slash and burn since in some cases, crop yield does not justify the soil degradation caused. To estimate the soil quality in agricultural and forest soils at different ages of the forest-fallow period (25, 35, and 50 years), this survey investigated rural areas in three locations in Manica province, central Mozambique: Vanduzi, Sussundenga, and Macate. Soil profiles were trenched and sampled with a pedological approach under crop fields and forest-fallow. The chronosequence was selected to test the hypothesis that the increase in forest-fallow age causes an improvement of soil fertility. Results highlighted discrete variations among locations in mineralogy, Al- and Fe-oxyhydroxides, sand, silt, pH, total organic carbon, humic carbon, total nitrogen, available phosphorous, chloride, nitrate, fluoride, and ammonium. Few differences in mineralogy, Fe-oxyhydroxides, available P, chloride, and nitrate were detected between crop fields and forest-fallow within the same location. Such differences were mostly ascribed to intrinsic fertility inherited from the parent material rather than a longer forest-fallow period. However, physicochemical soil property improvement did not occur under a forest age of 50 years (the longest forest-fallow considered), indicating that harmonization of intrinsic fertility and agronomic practices may increase soil organic matter and nutrient contents more than a long forest-fallow period. |
| Maqbool, Q., Czerwinska, N., Giosue, C., Sabbatini, S., Ruello, M.L. and Tittarelli, F., 2022. New waste-derived TiO2 nanoparticles as a potential photocatalytic additive for lime based indoor finishings. Journal of Cleaner Production, 373, p.133853. |
| Abstract: Production of sustainable nanomaterials (NMs) through the valorization of heterogeneous wastes is of high importance due to escalating environmental sustainability and depletion of natural resources. Following this motive, in this paper, TiO2 nanoparticles (NPs) were green-synthesized (GS) using metal ions reducing potential of secondary metabolites from organic waste (i.e., autumn leaves). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis revealed that GS TiO2-NPs as pure anatase for crystalline fraction, with homogenous granulometry ranging between 12 and 26 nm in size, and crystallite size as small as 3.85 (±0.02) nm are achieved. The effect of carbon-content (modifier) on the structural and surface chemistry of tested TiO2-NPs were deeply investigated through Fourier-transform infrared (FTIR) spectroscopy and thermogravimetry analysis (TG/DTG/DTA). The GS TiO2-NPs have shown photocatalytic (NO)x degradation of around 30% and 18% under UV and visible-light respectively, 10% and 70% higher than that of two commercial TiO2-NPs, P-25 and KRONOS-7404, respectively. Based on the leading performance, GS TiO2-NPs were further tested as an additive to an indoor hydraulic-lime based finishing material to augment its photocatalytic properties. Interestingly, GS TiO2-NPs were able to maintain (NO)x photodegradation (≈11%) performance even at an extremely small concentration of <2 wt%. Hence, waste-mediated production of ecofriendly GS TiO2-NPs introduced in this study will help for next-generation photocatalytic indoor finishing materials. |
| E. Laudadio, G. Mobbili, L. Sorci, R. Galeazzi, C. Minnelli, Mechanistic insight toward EGFR activation induced by ATP: role of mutations and water in ATP binding patterns, Journal of Biomolecular Structure and Dynamics, 1-10, 2022 |
| Abstract: The discovery of mutations within the kinase domain of the epidermal growth factor receptor (EGFR) gene has enabled a new era of targeted therapy in non-small cell lung cancer (NSCLC). Drugs belonging to the family of tyrosine kinase inhibitors (TKIs) are designed to bind ATP binding cleft, anyway, the occurrence of aminoacidic mutations decreases the effectiveness of the antitumoral treatment. Despite many efforts has been already made, the impact of the mutations on conformation and stability of EGFR-ATP complexes is still not fully understood. Therefore, we investigated the effect of mutations that leads to changes in Michaelis-Menten constant (Km) using dynamic docking simulations. We focused on six different EGFR forms in relation to different mutation states, then we found a good correlation between the calculated ATP affinities and Km values. Moreover, since dynamic switching of TK-EGFR from the inactive towards the active state is known to regulate the kinase activity, we observed that ATP induces the inwards movement of the αC-helix with the Lys745 close to Glu762 in all cases. This means that ATP binding should be the first step in promoting the conformational shift to the active state. Finally, we highlighted for the first time the key contribution of water hydrogen bond and water-bridge networks in the modulation of ATP affinity. The identified mutant-specific ATP binding patterns and conformational features could be much useful to guide cancer therapy and develop more personalized medicine. |
| E. Laudadio, C. Minnelli, G. Mobbili, G. Sabbatini, P. Stipa, D. Rusciano, and R. Galeazzi, Salt effects on mixed composition membranes containing an antioxidant lipophilic edaravone derivative: a computational-experimental study, Organic and Biomolecular Chemistry 20 (29), 5784 – 5795, 2022 |
| Abstract: The protection of lipid membranes against oxidation avoids diseases associated with oxidative stress. As a strategy to contrast it, functionalized lipids with antioxidant activity are used to become part of membranes thus protecting them. For this purpose, a lipophilic edaravone derivative has been synthesized, adding a C18 saturated chain to the original structure. The antioxidant activity of C18-Edv has been demonstrated in our previous work. In this study, molecular dynamics simulations have been performed to define the effects of NaCl, MgCl2, KCl, and CaCl2 salts on a palmitoyl-oleoyl-sn-glycero-phosphocholine (POPC) lipid bilayer encapsulating C18-Edv. The results showed how different salts influence POPC lateral diffusion, and the movements of C18-Edv heads, which are antioxidant moieties, were correlated to the ability of C18-Edv molecules to protect membranes. MgCl2 showed a negative impact leading to C18-Edv clusterization and membrane stretching, while KCl and NaCl showed a moderate influence on the mixed lipid membrane structure. CaCl2 increased the exposure of the C18-Edv heads to the lipid-water interface, resulting in the salt with a higher propensity to guarantee protection against radicals in the aqueous phase. Finally, C18-Edv-POPC liposomes have been prepared following the simulation conditions, and then an experimental Oxygen Radical Absorbance Capacity (ORAC) assay has been performed to confirm the in silico predicted results. |
| A. Scirè, L. Cianfruglia, C. Minnelli, B. Romaldi, E. Laudadio, R. Galeazzi, C. Antognelli, T. Armeni, Glyoxalase 2: Towards a Broader View of the Second Player of the Glyoxalase System, Antioxidants, 11 (11), 2131, 2022 |
| Abstract: Glyoxalase 2 is a mitochondrial and cytoplasmic protein belonging to the metallo-β-lactamase family encoded by the hydroxyacylglutathione hydrolase (HAGH) gene. This enzyme is the second enzyme of the glyoxalase system that is responsible for detoxification of the α-ketothaldehyde methylglyoxal in cells. The two enzymes glyoxalase 1 (Glo1) and glyoxalase 2 (Glo2) form the complete glyoxalase pathway, which utilizes glutathione as cofactor in eukaryotic cells. The importance of Glo2 is highlighted by its ubiquitous distribution in prokaryotic and eukaryotic organisms. Its function in the system has been well defined, but in recent years, additional roles are emerging, especially those related to oxidative stress. This review focuses on Glo2 by considering its genetics, molecular and structural properties, its involvement in post-translational modifications and its interaction with specific metabolic pathways. The purpose of this review is to focus attention on an enzyme that, from the most recent studies, appears to play a role in multiple regulatory pathways that may be important in certain diseases such as cancer or oxidative stress-related diseases. |
| E. Mohebbi, E. Pavoni, D. Mencarelli, P. Stipa, L. Pierantoni, E. Laudadio, Insights into first-principles characterization of the monoclinic VO2(B) polymorph via DFT + U calculation: electronic, magnetic and optical properties, Nanoscale Advances, 4, 3634-3646, 2022 |
| Abstract: We have studied the structural, electronic, magnetic, and optical properties of the VO2(B) polymorph using first-principles calculations based on density functional theory (DFT). This polymorph was found to display four optimized structures namely VO2(B)PP, VO2(B)LP, VO2(B)PPD, and VO2(B)LPD using the generalized gradient approximation (GGA) PBE exchange-correlation functional by including/excluding van der Waals interaction. Our derivation provides a theoretical justification for adding an on-site Coulomb U value in the conventional DFT calculations to allow a direct comparison of the two methods. We predicted a zero bandgap of the VO2(B) structure based on GGA/PBE. However, by GGA/PBE + U, we found accurate bandgap values of 0.76, 0.66, and 0.70 eV for VO2(B)PP, VO2(B)LP, and VO2(B)PPD, respectively. The results obtained from DFT + U were accompanied by a structural transition from the metallic to semiconductor property. Here, we verified the non-magnetic characteristic of the monoclinic VO2(B) phase with some available experimental and theoretical data. However, the debate on the magnetic property of this polymorph remains unresolved. Imaginary and real parts of the dielectric function, as computed with the GGA/PBE functional and the GGA/PBE + U functional, were also reported. The first absorption peaks of all considered geometries in the imaginary part of the dielectric constants indicated that the VO2(B) structure could perfectly absorb infrared light. The computed static dielectric constants with positive values, as derived from the optical properties, confirmed the conductivity of this material. Among the four proposed geometries of VO2(B) in this study, the outcomes obtained by VO2(B)PPD reveal good results owing to the excellent consistency of its bandgap, magnetic and optical properties with other experimental and theoretical observations. The theoretical framework in our study will provide useful insight for future practical applications of the VO2(B) polymorph in electronics and optoelectronics. |
| E. Mohebbi, E. Pavoni, D. Mencarelli, P. Stipa, L. Pierantoni, E. Laudadio, PBEsol/HSE functional: a promising candidate for vanadium dioxide (B) characterization, RSC Advances 12(48):31255-31263, 2022 |
| Abstract: A VO2(B) polymorph has been thoroughly investigated by means of density functional theory (DFT) calculations to evaluate the structure, Raman spectrum, cohesive energy, phonon band structure, an delectronic and optical properties. Among the computed Raman modes, eight of them have been assigned to the VO2(B) structure in full agreement with the corresponding experimental spectra. The minimized structure of the VO2(B) polymorph indicated the presence of negative frequencies in its phonon dispersion curves, confirming the dynamic instability of this material. Herein, the combination of generalized gradient approximation (GGA)/PBEsol with a hybrid HSE functional has been employed to perform ab initio calculations on VO2(B), since the conventional semi-local DFT calculations are believed to underestimate the band gap of materials. By considering the electronic structure calculations, for the first time, we found that the calibration of the PBEsol functional can efficiently model the metallic-like properties of VO2(B) with a band gap of 0.26 eV, while the corresponding electronic bandgap of VO2(B) based on the HSE functional possesses a larger band gap of 0.67 eV. The prediction of optical characteristics of VO2(B) indicated that the optical conductivity of VO2(B) lies in the infrared region of light. This work strongly suggests the combination of GGA/PBEsol with HSE hybrid functionals to carefully describe the physical properties of smart materials exploitable in electronics and optoelectronics applications. The nanostructure of VO2(B) looks promising for IR photodetectors and smart windows applications as a semiconductor material with excellent optical features. It is predicted that in the future VO2(B) will continue to expand the envelope of its capabilities because of its remarkable properties. |
| M. L. Naitana, W. R. Osterloh, L. Di Zazzo, S. Nardis, F. Caroleo, Pi. Stipa, K. N. Truong, K. Rissanen, Y. Fang, K. M. Kadish, and R. Paolesse, The Difficult Marriage of Triarylcorroles with Zinc and Nickel Ions, Inorganic Chemistry 61, 17790−17803, 2022 |
| Abstract: The coordination chemistry of corrole has witnessed a great improvement in the past few years and its Periodic Table has been widened to be so large that it is compared with that of porphyrins. However, Ni and Zn ions, commonly used with porphyrins for both synthetic and theoretical purposes, are sparsely reported in the case of corroles. Here, we report synthetic protocols for preparing Ni and Zn triarylcorrole complexes. In the case of Zn, the preliminary oxidation of the free base corrole in DMSO to the neutral corrole radical is a necessary step to obtain the coordination of the metal ion, because the direct reaction led to the formation of an open-chain tetrapyrrole. The Ni complex could be directly obtained by heating the free base corrole and Ni(II) salt to 100 °C in a DMSO solution containing FeCl3. The non-innocent nature of the corrole ligand for both complexes has been elucidated by EPR, and in the case of the Zn derivative the first spectroelectrochemical characterization is presented. |
| Cristina Minnelli, Pierluigi Stipa, Simona Sabbatini, Paolo Mengucci, Giovanna Mobbili, Roberta Galeazzi, Tatiana Armeni, Brenda Romaldi, Annamaria Celli, Emiliano Laudadio . New waste-derived. Insights into PLGA-encapsulated epigallocatechin 3-gallate nanoparticles as a new potential biomedical system: A computational and experimental approach, European Polymer Journal 182 (2023) 111723 |
| Biodegradable poly-lactic poly-glycolic copolymer (PLGA) represents one of the best strategies adopted to convey small molecules unstable and characterised by a low bioavailability if administered without vehicles. This is the case of Epigallocatechin-3-gallate (EGCG), which is one of the most interesting polyphenols from a biomedical point of view. In this study, the impact of EGCG on PLGA nanoparticles (NPs) properties has been studied underlining the role of the binary PVA/Poloxamer-407 as stabilizer system for obtaining colloidal stable NPs. Characterization has been carried out by dynamic light scattering (DLS), encapsulation efficiency, drug release studies, scanning electron microscopy (SEM) and infrared spectroscopy (IR). Molecular dynamics (MD) simulations have been used to model the PLGA and EGCG systems to understand the behaviour of NPs and the interactions that guided the EGCG encapsulation. The nanodispersions exhibited promising cytotoxic potentials in human lung carcinoma A549 cell lines enhancing the well-known growth inhibitor effect of the free EGCG. |
| R. Barboza1, S. Marni1, F. Ciciulla1, F. Ali Mir1 , G. Nava2, F. Caimi2, A. Zaltron3, N. Clark4 , T. Bellini2*, L. Lucchetti1*, Explosive electrostatic instability of ferroelectric liquid droplets on ferroelectric solid surfaces, Proceedings of the National Academy of Sciences of the United States of America (PNAS) 119(32) e2207858119 (2022) |
| Abstract: We investigated the electrostatic behavior of ferroelectric liquid droplets exposed to the pyroelectric field of a lithium niobate ferroelectric crystal substrate. The ferroelectric liquid is a nematic liquid crystal, in which almost complete polar ordering of the molecular dipoles generates an internal macroscopic polarization locally collinear to the mean molecular long axis. Upon entering the ferroelectric phase by reducing the temperature from the nematic phase, the liquid crystal droplets become electromechanically unstable and disintegrate by the explosive emission of fluid jets. These jets are mostly interfacial, spreading out on the substrate surface, and exhibit fractal branching out into smaller streams to eventually disrupt, forming secondary droplets. We understand this behavior as a manifestation of the Rayleigh instability of electrically charged fluid droplets, expected when the electrostatic repulsion exceeds the surface tension of the fluid. In this case, the charges are due to the bulk polarization of the ferroelectric fluid, which couples to the pyroelectric polarization of the underlying lithium niobate substrate through its fringing field and solid-fluid interface coupling. Since the ejection of fluid does not neutralize the droplet surfaces, they can undergo multiple explosive events as the temperature decreases. |
| Cervi and A. Tazioli, Applying Artificial and Environmental Tracing Techniques in Hydrogeology, Water 14 (17), 2618, 2022 |
| Abstract: This Editorial paper sums up the contents of the Special Issue named “Applying Artificial and Environmental Tracing Techniques in Hydrogeology”. With reference to the topic of the Special Issue, here we recall that over the last decades, the use of artificial (i.e., intentionally introduced into the hydrogeological system, such as dyes) and environmental (i.e., entering as a part of the hydrological cycle, such as water isotopes) tracers in groundwater sciences has remarkably increased demonstrating their usefulness in solving hydrogeological problems at different spatial and time scales. Such tracers are used both in laboratory experiments (column tests) and field investigations (even at catchments and regional scales) and deal with water residence times lasting from few minutes to many millennia. They are recognized as powerful tools for obtaining information that cannot be gained by any other conventional means, such as depicting groundwater flow-paths and mixing processes among different end-members, identifying a connection between surficial water and groundwater, estimating the recharge areas of infiltrative water and quantifying pre-infiltrative evaporative processes and groundwater residence times. To date, many artificial and environmental tracers have been tested and the specific choice of a suitable one (or a subset of them; multi-tracing techniques) strictly depends on which hydrogeological investigation has to be conducted. |
| E. Mammoliti, F. Di Stefano, D. Fronzi, A. Mancini, E.S. Malinverni and A. Tazioli, A Machine Learning Approach to Extract Rock Mass Discontinuity Orientation and Spacing, from Laser Scanner Point Clouds, Remote Sensing 14 (10), 2365, 2022 |
| Abstract: This study wants to give a contribution to the semi-automatic evaluation of rock mass discontinuities, orientation and spacing, as important parameters used in Engineering. In complex and inaccessible study areas, a traditional geological survey is hard to conduct, therefore, remote sensing techniques have proven to be a very useful tool for discontinuity analysis. However, critical expert judgment is necessary to make reliable analyses. For this reason, the open-source Python tool named DCS (Discontinuities Classification and Spacing) was developed to manage point cloud data. The tool is written in Python and is based on semi-supervised clustering. By this approach the users can: (a) estimate the number of discontinuity sets (here referred to as “clusters”) using the Error Sum of Squares (SSE) method and the K-means algorithm; (b) evaluate step by step the quality of the classification visualizing the stereonet and the scatterplot of dip vs. dip direction from the clustering; (c) supervise the clustering procedure through a manual initialization of centroids; (d) calculate the normal spacing. In contrast to other algorithms available in the literature, the DCS method does not require complex parameters as inputs for the classification and permits the users to supervise the procedure at each step. The DCS approach was tested on the steep coastal cliff of Ancona town (Italy), called the Cardeto–Passetto cliff, which is characterized by a complex fracturing and is largely affected by rockfall phenomena. The results of discontinuity orientation were validated with the field survey and compared with the ones of the FACETS plug-in of CloudCompare. In addition, the algorithm was tested and validated on regular surfaces of an anthropic wall located at the bottom of the cliff. Eventually, a kinematic analysis of rock slope stability was performed, discussing the advantages and limitations of the methods considered and making fundamental considerations on their use. |
| F. C. Adamo, F. Ciuchi, M. P. De Santo, P. Astolfi, I. Warner, E. Scharrer, M. Pisani, F. Vita, and O. Francescangeli, Nanoscale structure of Langmuir–Blodgett film of bent-core molecules, Nanomaterials 12 (13), 2285, 2022 |
| Abstract: Bent-core mesogens (BCMs) are a class of thermotropic liquid crystals featuring several unconventional properties. However, the interpretation and technological exploitation of their unique behavior have been hampered by the difficulty of controlling their anchoring at surfaces. To tackle this issue, we report the nanoscale structural characterization of BCM films prepared using the Langmuir–Blodgett technique. Even though BCMs are quite different from typical amphiphilic molecules, we demonstrate that stable molecular films form over water, which can then be transferred onto silicon substrates. The combination of Brewster angle microscopy, atomic force microscopy, and X-ray reflectivity measurements shows that the molecules, once transferred onto a solid substrate, form a bilayer structure with a bottom layer of flat molecules and an upper layer of upright molecules. These results suggest that Langmuir–Blodgett films of BCMs can provide a useful means to control the alignment of this class of liquid crystals. |
| L. Spina, M. P. De Santo, C. M. Tone, M. Pisani, F. Vita, R. Barberi, and F. Ciuchi, Intercalation or external binding: How to torque chromonic Sunset Yellow, Journal of Molecular Liquids 359, 119265, 2022 |
| Abstract: The reflection symmetry breaking observed in chromonic liquid crystals confined in different geometries, like tactoids, microspheres or capillaries, has been the focus of researchers in the last few years. Although the assembly mechanism that drives this behavior is common to most chromonic materials, the interface phenomena and the induced chirality are strongly dependent on the chromonic molecule itself. In this work, we report advances in understanding the supramolecular arrangement and induced chirality for the chromonic molecule Sunset Yellow and its interaction with salts and L-peptides. By means of optical microscopy, X-ray diffraction and atomic force microscopy, we demonstrate the rise of enhanced chirality in Sunset Yellow microspheres and propose an explanation of this phenomenon through two possible mechanisms: intercalation of the chiral dopant or binding. Our findings on the capability to control the delicate thermodynamic balance among chromonics, ions, chiral dopants, and water and its kinetics may open new perspectives for using these microspheres in optical and sensing applications. |
| D. E. Lucchetta, L. Schiaroli, G. Battista, M. Martarelli, and P. Castellini Experimental acoustic modal analysis of a tenor saxophone The Journal of the Acoustical Society of America 152, 2629 (2022) https://doi.org/10.1121/10.0015052 |
| Abstract: This paper presents an application of the Experimental Acoustic Modal Analysis (AMA) on a vintage 10 M Conn tenor saxophone. This technique originates from the traditional Modal Analysis which is commonly adopted to determine the dynamic behaviour of solid structures. The methodology is based on the measurement of Frequency Response Functions (FRFs) as a ratio of the acoustic pressure, measured by means of a set of microphones positioned along the saxophone body, and the volume velocity produced by an acoustic source and measured at the instrument input. The microphones are housed on the stripped saxophone keys by means of tailored three-dimensional printed adapters. The AMA makes use of the FRFs to extract modal parameters, such as resonance frequencies, loss factors, and mode shapes. These parameters pertain to the cavity modes of the saxophone passive resonator. The analysis has been performed for three different notes (B♭, B, and C) and for two registers of the instrument in order to show the potential of the technique. Moreover, the influence of the mouthpiece volume on the cavity modes has been shown. The information obtained by AMA can find useful application in the validation of analytical or numerical models of this kind of musical instruments. |
| Lucchetta D.E., Di Donato A., Francescangeli O., Singh G., Castagna R. Light-Controlled Direction of Distributed Feedback Laser Emission by Photo-Mobile Polymer Films(2022) Nanomaterials, 12 (17), art. no. 2890 DOI: 10.3390/nano12172890 |
| Abstract: We report on the realization of Distributed Feedback (DFB) lasing by a high-resolution reflection grating integrated in a Photomobile Polymer (PMP) film. The grating is recorded in a recently developed holographic mixture basically containing halolakanes/acrylates and a fluorescent dye molecule (Rhodamine 6G). The PMP-mixture is placed around the grating spot and a subsequent curing/photo-polymerization process is promoted by UV-irradiation. Such a process brings to the simultaneous formation of the PMP-film and the covalent link of the PMP-film to the DFB-grating area (PMP-DFB system). The PMP-DFB allows lasing action when optically pumped with a nano-pulsed green laser source. Moreover, under a low-power light-irradiation the PMP-DFB bends inducing a spatial readdressing of the DFB-laser emission. This device is the first example of a light-controlled direction of a DFB laser emission. It could represent a novel disruptive optical technology in many fields of Science, making feasible the approach to free standing and light-controllable lasers. |
| Castagna R., Di Donato A., Strangi G., Lucchetta D.E. Light controlled bending of a holographic transmission phase grating (2022) Smart Materials and Structures, 31 (3), art. no. 03LT02 DOI: 10.1088/1361-665X/ac4a47 |
| Abstract: We recorded a permanent phase transmission grating on a thin film made by using a recently developed holographic photomobile mixture. The recorded grating pitch falls in the visible range and can be optically manipulated by using an external coherent or incoherent low power light source. When the external light source illuminates the grating the entire structure bends and, as a consequence, the optical properties of the grating change. This peculiarity makes it possible to use the recorded periodic structure as an all-optically controlled free standing thin colour selector or light switch depending on the source used to illuminate the grating itself. Additionally, it could open up new possibilities for stretchable and reconfigurable holograms controlled by light as well as thin devices for optically reconfigurable dynamic communications and displays. © 2022 IOP Publishing Ltd.. |
| Castagna R., Di Donato A., Francescangeli O., Lucchetta D.E. Polymer-Based High Diffraction Efficiency and High Resolution Volume Holographic Transmission Gratings (2022) Chemosensors, 10 (9), art. no. 356 DOI: 10.3390/chemosensors10090356 |
| Abstract: ABSTRACT: We report on the optical characterization of very high-efficiency and high-resolution holographic volume phase transmission gratings. The gratings are recorded in a new photo-polymerizable mixture made by epoxy-resin and multi-acrylate. The epoxy-resin used is known to make tenacious acrylate-based films. The holographic mixture contains two photo-initiators, the synergic effect of which enables a reliable photo-polymerization process in the visible region of the electromagnetic spectrum. The recorded holograms are mechanically stable, show long-term temporal stability and very high values of diffraction efficiency, coupled with good angular selectivity due to a relatively narrow band of wavelengths. We measured the intensity of the transmitted beam and calculated the intensity of the diffracted beam at different wavelengths, deriving the refractive index modulation and the grating pitch by fitting the experimental data with a slightly modified theoretical approach. These kind of mixtures can be used in several fields of application, such as chemical or bio-sensors, high resolution optical sensors, high-density optical data storage, encryption and security. © 2022 by the authors. |
| Castagna R., Tombesi A., Riminesi C., Di Donato A., Francescangeli O., Lucchetta D.E. HKUST-1-Doped High-Resolution Volume Holographic Gratings (2022) Chemosensors, 10 (8), art. no. 310, DOI: 10.3390/chemosensors10080310 |
| Abstract: We report on transmission holographic gratings doped with metal organic frameworks (MOFs). As a first attempt, we focused on MOF-199, also known as HKUST-1, which is an efficient adsorbent of VOCs. HKUST-1 is not soluble in the pre-polymerized holographic mixture. For this reason, samples containing HKUST-1 show high light scattering. In this work, the recording of HKUST-1-doped one-dimensional transmission phase gratings is demonstrated. The optical properties of the recorded structures, such as diffraction efficiency and average refractive index changes, are reported by using angular analysis measurements. A first attempt to demonstrate the possibility of using the doped gratings as sensors is also reported. © 2022 by the authors. |
| Puglia, D.; Luzi, F.; Torre, L. Preparation and Applications of Green Thermoplastic and Thermosetting Nanocomposites Based on Nanolignin. Polymers 2022, 14, 5470. https://doi.org/10.3390/polym14245470 |
| Abstract: The development of bio-based materials is of great importance in the present environmental circumstances; hence, research has greatly advanced in the valorization of lignin from lignocellulosic wastes. Lignin is a natural polymer with a crosslinked structure, valuable antiradical activity, unique thermal- and UV-absorption properties, and biodegradability, which justify its use in several prospective and useful application sectors. The active functionalities of lignin promote its use as a valuable material to be adopted in the composite and nanocomposites arenas, being useful and suitable for consideration both for the synthesis of matrices and as a nanofiller. The aim of this review is to summarize, after a brief introduction on the need for alternative green solutions to petroleum-based plastics, the synthesis methods for bio-based and/or biodegradable thermoplastic and thermosetting nanocomposites, along with the application of lignin nanoparticles in all green polymeric matrices, thus generating responsiveness towards the sustainable use of this valuable product in the environment. |
| Lombardi, A.; Fochetti, A.; Vignolini, P.; Campo, M.; Durazzo, A.; Lucarini, M.; Puglia, D.; Luzi, F.; Papalini, M.; Renzi, M.; Cavallo, A.; Bernini, R. Natural Active Ingredients for Poly (Lactic Acid)-Based Materials: State of the Art and Perspectives. Antioxidants 2022, 11, 2074. https://doi.org/10.3390/antiox11102074 |
| Abstract: This review describes the state of the art in the field of poly (lactic acid) (PLA)-based materials activated by natural compounds and extracts (active ingredients, AIs) from plant sources for food and biomedical applications. With a multidisciplinary approach, after a description of the synthesis and properties of PLA, special attention was paid to the chemical properties and unconventional extraction technologies of AIs used for PLA activation. Innovative techniques for the incorporation of AIs into PLA; characterization and the antioxidant and antimicrobial properties of the novel materials were discussed. In view of future perspectives, this study has evidenced that some aspects need to be further investigated from joint research between academia and industry, according to the green chemistry principles and circular economy strategy. |
| Carolina Catanio Bortolan, Leonardo Contri Campanelli, Paolo Mengucci, Gianni Barucca, Nicolas Giguèred, Nicolas Brodusch, Carlo Paternoster, Claudemiro Bolfarini, Raynald Gauvin, Diego Mantovani, Development of Ti-Mo-Fe alloys combining different plastic deformation mechanisms for improved strength-ductility trade-off and high work hardening rate, Journal of Alloys and Compounds 925 (2022) 166757 |
| Abstract: Titanium-based biomaterials are the gold standard for orthopedic implants; however, they are not generally suitable for the manufacture of intravascular stents. Their low strength-ductility trade-off and low work hardening rate are their main limitations. However, Ni-free alloys are desirable for such application in order to avoid allergic reactions caused by the high Ni-content materials currently applied. Therefore, in this study, three alloys of the Ti-Mo-Fe system (Ti-8Mo-2Fe, Ti-9Mo-1Fe and Ti-10.5Mo-1Fe) were designed to present high strength-ductility compromise and high work hardening rate. Their microstructures, mechanical properties and plastic deformation mechanism were investigated. Athermal ω precipitates were observed in the β matrix of all solution-treated alloys. In the solution-treated β matrix of the Ti-9Mo-1Fe alloy, additional nanometer-sized α” particles were detected by transmission electron microscopy (TEM). Although the combined TWIP/TRIP effects were expected by the design method on the Ti-8Mo-2Fe and Ti- 9Mo-1Fe alloys, no TRIP effect was actually observed. In fact, stress-induced martensitic (SIM) transformation occurred mainly at the {332} < 113 > twins/matrix interfaces for all the strained microstructures and acted as a localized stress-relaxation mechanism, delaying the fracture. Based on the electron backscatter diffraction (EBSD) analyses, in the Ti-8Mo-2Fe and Ti-10.5Mo-1Fe alloys, the formation of a dense network of {332} < 113 > twins was responsible for their high and steady work hardening rates (1370 and 1120 MPa) and large uniform elongations (22% and 34%). The absence of SIM α” as the primary mechanism of plastic deformation and solid solution hardening of Fe resulted in their high strengths (yield strength of 772 and 523 MPa). In Ti-9Mo-1Fe, the formation of mechanical twinning was hindered, resulting in limited strain- hardening capability and low uniform elongation (6%). The nanometer-sized α” particles in its β matrix along with the athermal ω precipitates are thought to impair the mechanical twinning and the ductility of this alloy. |
| Letícia Marin de Andrade, Carlo Paternoster, Pascale Chevallier, Sofia Gambaro, Paolo Mengucci, Diego Mantovani, Surface processing for iron-based degradable alloys: A preliminary study on the importance of acid pickling, Bioactive Materials 11 (2022) 166–180 |
| Abstract: The formation of a heterogeneous oxidized layer, also called scale, on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys. Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices. For biodegradable metals, acid pickling has already been reported as a preliminary surface preparation given further processes, such as electropolishing. Unfortunately, biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry (e.g., non-uniform scale removal and rougher surface). Indeed, this translational knowledge lacks a detailed investigation on this process, deep characterization of treated surfaces properties, as well as a comprehensive discussion of the involved mechanisms. In this study, the effects of different acidic media (HCl, HNO3, H3PO4, CH3COOH, H2SO4 and HF), maintained at different temperatures (21 and 60 ◦C) for various exposition time (15–240 s), on the chemical composition and surface properties of a Fe–13Mn-1.2C biodegradable alloy were investigated. Changes in mass loss, morphology and wettability evidenced the combined effect of temperature and time for all conditions. Pickling in HCl and HF solutions favor mass loss (0.03–0.1 g/cm2) and effectively remove the initial scale. |
| Samira Ravanbakhsh, Carlo Paternoster, Gianni Barucca, Paolo Mengucci, Sofia Gambaro, Theophraste Lescot, Pascale Chevallier, Marc-Andr´e Fortin, Diego Mantovani, Improving the radiopacity of Fe–Mn biodegradable metals by magnetron-sputtered W–Fe–Mn–C coatings: Application for thinner stents, Bioactive Materials 12 (2022) 64–70 |
| Abstract: In this exploratory work, micrometric radiopaque W–Fe–Mn–C coatings were produced by magnetron sputtering plasma deposition, for the first time, with the aim to make very thin Fe–Mn stents trackable by fluoroscopy. The power of Fe–13Mn-1.2C target was kept constant at 400 W while that of W target varied from 100 to 400 W producing three different coatings referred to as P100, P200, P400. The effect of the increased W power on coatings thickness, roughness, structure, corrosion behavior and radiopacity was investigated. The coatings showed a power-dependent thickness and W concentration, different roughness values while a similar and uniform columnar structure. An amorphous phase was detected for both P100 and P200 coatings while γ-Fe, bcc- W and W3C phases found for P400. Moreover, P200 and P400 showed a significantly higher corrosion rate (CR) compared to P100. The presence of W, W3C as well as the Fe amount variation determined two different micro-galvanic corrosion mechanisms significantly changing the CR of coatings, 0.26 ± 0.02, 59.68 ± 1.21 and 59.06 ± 1.16 μm/year for P100, P200 and P400, respectively. Sample P200 with its most uniform morphology, lowest roughness (RMS = 3.9 ± 0.4 nm) and good radiopacity (~6%) appeared the most suitable radiopaque biodegradable coating investigated in this study. |
| Flavia Vitiello, Vincenzo Tosco, Riccardo Monterubbianesi, Giulia Orilisi, Maria Laura Gatto , Scilla Sparabombe, Lucia Memé, Paolo Mengucci, Angelo Putignano, Giovanna Orsini, Remineralization Efficacy of Four Remineralizing Agents on Artificial Enamel Lesions: SEM-EDS Investigation, Materials 2022, 15, 4398 |
| Abstract: Dental remineralization represents the process of depositing calcium and phosphate ions into crystal voids in demineralized enamel, producing net mineral gain and preventing early enamel lesions progression. The aim of the present study was to qualitatively and quantitatively compare the remineralizing effectiveness of four commercially available agents on enamel artificial lesions using Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectroscopy (EDS) techniques. Thirty-six extracted third molars were collected and randomly assigned to six groups (n = 6), five of which were suspended in demineralizing solution for 72 h to create enamel artificial lesions, and one serving as control: G1, treated with a mousse of casein phosphopeptide and amorphous calcium–phosphate (CPP-ACP); G2, treated with a gel containing nano-hydroxyapatite; G3, treated with a 5% SF varnish; G4, treated with a toothpaste containing ACP functionalized with fluoride and carbonate-coated with citrate; G5, not-treated artificial enamel lesions; G6, not demineralized and not treated sound enamel. G1–G4 were subjected to pH cycling over a period of seven days. Analyses of the specimens’ enamel surfaces morphology were performed by SEM and EDS. Data were statistically analyzed for multiple group comparison by one-way ANOVA/Tukey’s test (p < 0.05). The results show that the Ca/P ratio of the G5 (2.00 _ 0.07) was statistically different (p < 0.05) from G1 (1.73 _ 0.05), G2 (1.76 _ 0.01), G3 (1.88 _ 0.06) and G6 (1.74 _ 0.04), while there were no differences (p > 0.05) between G1, G2 and G6 and between G4 (2.01 _ 0.06) and G5. We concluded that G1 and G2 showed better surface remineralization than G3 and G4, after 7 days of treatment. |
| Andrea Gatto, Maria Laura Gatto, Riccardo Groppo, Daniel Munteanu, Paolo Mengucci, Influence of laser powder bed fusion process parameters on the properties of CuZn42 components: case study of the laser surface energy density, Progress in Additive Manufacturing https://doi.org/10.1007/s40964-022-00361-z |
| Abstract: Although additive manufacturing (AM) technologies have been rarely used to produce lead-containing brass, the same AM technologies have never been adopted to produce lead-free brass parts based on the CuZn42 alloy. This study aims to fill the gap, demonstrating the feasibility of lead-free brass alloys by laser powder bed fusion (LPBF) technology and investigating structural and mechanical properties of the produced specimens, focusing attention on the role of surface energy density on material properties. Starting from a raw powder of CuZn42 alloy containing α, β and γ brass phases, fully dense samples with high hardness values were obtained by LPBF. The structural and mechanical properties of the samples were investigated by scanning electron microscopy (SEM), energy-dispersive microanalysis (EDS), X-ray diffraction (XRD) and density and hardness measurements. Results showed that density, hardness and the relative amount of the brass phases depend on the surface energy density (SED) Es. The investigated range of SED allowed defining the process window ranging from 2 J/mm2 to 10 J/mm2, within which fully dense samples can be obtained. A linear dependence of hardness on density was also found, suggesting that deformation mechanisms are mainly due to the presence of residual pores and internal cavities rather than to microstructural features, such as the relative amount of brass phases and crystallographic defects. All results obtained in this work demonstrated, for the first time, that LPBF is suitable to produce components based on the CuZn42 alloy, and that structural and mechanical properties of the produced parts can be properly designed by controlling SED. |
| TamilSelvi Selvam, Petar Pervan, Jordi Sancho-Parramon, Maria Chiara Spadaro, Jordi Arbiol, Vesna Janicki Glass poling as a substrate surface pre-treatment for in situ metal nanoparticle formation by reduction of metal salt Surfaces and Interfaces 33, 102158, 2022 |
| Abstract: Metal nanoparticles are used in optical coatings and sensors due to their absorption in optical part of spectrum and its sensitivity to the environment induced by localized surface plasmon resonance. Glass is the most common substrate used for optical coatings. However, its surface does not have optimal properties for coating with metal nanoparticles grown in situ by reduction of metal salt. Glass surface optimization methods may involve environmentally hostile chemicals or processes that have time limited or atmosphere sensitive effects. In this study it is demonstrated and discussed effectiveness, mechanisms and advantages of glass poling as pre-treatment method for improving glass surface properties for maximization of coatings plasmonic performance. Pre-treatment of glass surfaces by poling is highly efficient for the purpose. Glass poling quenches ion exchange between metal ions from the solution and alkali ions from glass, favouring nanoparticles formation. Surface prepared in such way is not affected by ageing in normal atmosphere and is effective even after coating with ultrathin dielectric or Cr layers. |
| Cheng Chang, Yu Liu, Seung Ho Lee, Maria Chiara Spadaro, Kristopher M Koskela, Tobias Kleinhanns, Tommaso Costanzo, Jordi Arbiol, Richard L Brutchey, Maria Ibáñez Surface Functionalization of Surfactant‐Free Particles: A Strategy to Tailor the Properties of Nanocomposites for Enhanced Thermoelectric Performance Angewandte Chemie 134 (35), e202207002, 2022 |
| Abstract: The broad implementation of thermoelectricity requires high-performance and low-cost materials. One possibility is employing surfactant-free solution synthesis to produce nanopowders. We propose the strategy of functionalizing “naked” particles’ surface by inorganic molecules to control the nanostructure and, consequently, thermoelectric performance. In particular, we use bismuth thiolates to functionalize surfactant-free SnTe particles’ surfaces. Upon thermal processing, bismuth thiolates decomposition renders SnTe-Bi2S3 nanocomposites with synergistic functions: 1) carrier concentration optimization by Bi doping; 2) Seebeck coefficient enhancement and bipolar effect suppression by energy filtering; and 3) lattice thermal conductivity reduction by small grain domains, grain boundaries and nanostructuration. Overall, the SnTe-Bi2S3 nanocomposites exhibit peak z T up to 1.3 at 873 K and an average z T of ≈0.6 at 300–873 K, which is among the highest reported for solution-processed SnTe. |
| Junshan Li, Xi Tian, Xiang Wang, Ting Zhang, Maria Chiara Spadaro, Jordi Arbiol, Luming Li, Yong Zuo, Andreu Cabot Electrochemical Conversion of Alcohols into Acidic Commodities on Nickel Sulfide Nanoparticles Inorganic Chemistry 61 (34), 13433-13441, 2022 |
| Abstract: The electrocatalytic oxidation of alcohols is a potentially cost-effective strategy for the synthesis of valuable chemicals at the anode while simultaneously generating hydrogen at the cathode. For this approach to become commercially viable, high-activity, low-cost, and stable catalysts need to be developed. Herein, we demonstrate an electrocatalyst based on earth-abundant nickel and sulfur elements. Experimental investigations reveal the produced NiS displays excellent electrocatalytic performance associated with a higher electrochemical surface area (ECSA) and the presence of sulfate ions on the formed NiOOH surface in basic media. The current densities reached for the oxidation of ethanol and methanol at 1.6 V vs reversible hydrogen electrode (RHE) are up to 175.5 and 145.1 mA cm–2, respectively. At these high current densities, the Faradaic efficiency of methanol to formate conversion is 98% and that of ethanol to acetate is 81%. Density functional theory calculations demonstrate the presence of the generated sulfate groups to modify the electronic properties of the NiOOH surface, improving electroconductivity and electron transfer. Besides, calculations are used to determine the reaction energy barriers, revealing the dehydrogenation of ethoxy groups to be more favorable than that of methoxy on the catalyst surface, which explains the highest current densities obtained for ethanol oxidation. |
| Sara Martí-Sánchez, Marc Botifoll, Eitan Oksenberg, Christian Koch, Carla Borja, Maria Chiara Spadaro, Valerio Di Giulio, Quentin Ramasse, F Javier García de Abajo, Ernesto Joselevich, Jordi Arbiol Sub-nanometer mapping of strain-induced band structure variations in planar nanowire core-shell heterostructures Nature Communications 13 (1), 1-10, 2022 |
| Abstract: Strain relaxation mechanisms during epitaxial growth of core-shell nanostructures play a key role in determining their morphologies, crystal structure and properties. To unveil those mechanisms, we perform atomic-scale aberration-corrected scanning transmission electron microscopy studies on planar core-shell ZnSe@ZnTe nanowires on α-Al2O3 substrates. The core morphology affects the shell structure involving plane bending and the formation of low-angle polar boundaries. The origin of this phenomenon and its consequences on the electronic band structure are discussed. We further use monochromated valence electron energy-loss spectroscopy to obtain spatially resolved band-gap maps of the heterostructure with sub-nanometer spatial resolution. A decrease in band-gap energy at highly strained core-shell interfacial regions is found, along with a switch from direct to indirect band-gap. These findings represent an advance in the sub-nanometer-scale understanding of the interplay between structure and electronic properties associated with highly mismatched semiconductor heterostructures, especially with those related to the planar growth of heterostructured nanowire networks. |
| Ramón Arcas, Drialys Cardenas-Morcoso, Maria Chiara Spadaro, Miguel García-Tecedor, Camilo A Mesa, Jordi Arbiol, Francisco Fabregat-Santiago, Sixto Giménez, Elena Mas-Marzá Direct Observation of the Chemical Transformations in BiVO4 Photoanodes upon Prolonged Light‐Aging Treatments Solar RRL 6 (7), 2200132, 2022 |
| Abstract: Exposing BiVO4 photoanodes to light-aging treatments is known to produce a significant photocurrent enhancement. Until now, the interpretation given to this phenomenon is associated to the formation of oxygen vacancies and little is reported about chemical changes in the material. Herein, the chemical segregation of Bi species toward the surface upon light-aging treatment is demonstrated, which takes place with the concomitant formation of intra-bandgap states associated to the oxygen vacancies. It is further demonstrated that these intra-bandgap states are photoactive and generate photocurrent under infrared excitation. These results highlight the importance of understanding light-induced effects while employing multinary metal oxide photoelectrodes. |
| Daria V Beznasyuk, Sara Martí-Sánchez, Jung-Hyun Kang, Rawa Tanta, Mohana Rajpalke, Tomaš Stankevič, Anna Wulff Christensen, Maria Chiara Spadaro, Roberto Bergamaschini, Nikhil N Maka, Christian Emanuel N Petersen, Damon J Carrad, Thomas Sand Jespersen, Jordi Arbiol, Peter Krogstrup Doubling the mobility of InAs/InGaAs selective area grown nanowires Physical Review Materials 6 (3), 034602, 2022 |
| Abstract: Selective area growth (SAG) of nanowires and networks promise a route toward scalable electronics, photonics, and quantum devices based on III-V semiconductor materials. The potential of high-mobility SAG nanowires however is not yet fully realised, since interfacial roughness, misfit dislocations at the nanowire/substrate interface and nonuniform composition due to material intermixing all scatter electrons. Here, we explore SAG of highly lattice-mismatched InAs nanowires on insulating GaAs(001) substrates and address these key challenges. Atomically smooth nanowire/substrate interfaces are achieved with the use of atomic hydrogen (a-H) as an alternative to conventional thermal annealing for the native oxide removal. The problem of high lattice mismatch is addressed through an InxGa1−xAs buffer layer introduced between the InAs transport channel and the GaAs substrate. The Ga-In material intermixing observed in both the buffer layer and the channel is inhibited via careful tuning of the growth temperature. Performing scanning transmission electron microscopy and x-ray diffraction analysis along with low-temperature transport measurements we show that optimized In-rich buffer layers promote high-quality InAs transport channels with the field-effect electron mobility over 10 000 cm2 V−1 s−1. This is twice as high as for nonoptimized samples and among the highest reported for InAs selective area grown nanostructures. |
| Elias Z Stutz, Santhanu P Ramanandan, Mischa Flór, Rajrupa Paul, Mahdi Zamani, Simon Escobar Steinvall, Diego Armando Sandoval Salaiza, Clàudia Xifra Montesinos, Maria Chiara Spadaro, Jean-Baptiste Leran, Alexander P Litvinchuk, Jordi Arbiol, Anna Fontcuberta i Morral, Mirjana Dimitrievska Stoichiometry modulates the optoelectronic functionality of zinc phosphide (Zn 3− x P 2+ x) Faraday Discussions 239, 202-218, 2022 |
| Abstract: Predictive synthesis–structure–property relationships are at the core of materials design for novel applications. In this regard, correlations between the compositional stoichiometry variations and functional properties are essential for enhancing the performance of devices based on these materials. In this work, we investigate the effect of stoichiometry variations and defects on the structural and optoelectronic properties of monocrystalline zinc phosphide (Zn3P2), a promising compound for photovoltaic applications. We use experimental methods, such as electron and X-ray diffraction and Raman spectroscopy, along with density functional theory calculations, to showcase the favorable creation of P interstitial defects over Zn vacancies in P-rich and Zn-poor compositional regions. Photoluminescence and absorption measurements show that these defects create additional energy levels at about 180 meV above the valence band. Furthermore, they lead to the narrowing of the bandgap, due to the creation of band tails in the region of around 10–20 meV above the valence and below the conduction band. The ability of zinc phosphide to form off-stoichiometric compounds provides a new promising opportunity for tunable functionality that benefits applications. In that regard, this study is crucial for the further development of zinc phosphide and its application in optoelectronic and photovoltaic devices, and should pave the way for defect engineering in this kind of material. |
| Jiahao Yu, Felipe A. Garcés-Pineda, Jesús González-Cobos, Marina Peña-Díaz, Celia Rogero, Sixto Giménez, Maria Chiara Spadaro, Jordi Arbiol, Sara Barja & José Ramón Galán-Mascarós Sustainable oxygen evolution electrocatalysis in aqueous 1 M H2SO4 with earth abundant nanostructured Co3O4 Nature Communications 13, 4341, 2022 Nature Communications 13(1), 4687, 2022 (Author Correction) |
| Abstract: Earth-abundant electrocatalysts for the oxygen evolution reaction (OER) able to work in acidic working conditions are elusive. While many first-row transition metal oxides are competitive in alkaline media, most of them just dissolve or become inactive at high proton concentrations where hydrogen evolution is preferred. Only noble-metal catalysts, such as IrO2, are fast and stable enough in acidic media. Herein, we report the excellent activity and long-term stability of Co3O4-based anodes in 1 M H2SO4 (pH 0.1) when processed in a partially hydrophobic carbon-based protecting matrix. These Co3O4@C composites reliably drive O2 evolution a 10 mA cm–2 current density for >40 h without appearance of performance fatigue, successfully passing benchmarking protocols without incorporating noble metals. Our strategy opens an alternative venue towards fast, energy efficient acid-media water oxidation electrodes. |
| Yu Liu, Mariano Calcabrini, Yuan Yu, Seungho Lee, Cheng Chang, Jérémy David, Tanmoy Ghosh, Maria Chiara Spadaro, Chenyang Xie, Oana Cojocaru-Mirédin, Jordi Arbiol, and Maria Ibáñez Defect Engineering in Solution-Processed Polycrystalline SnSe Leads to High Thermoelectric Performance ACS NANO 16 (1), 78-88, 2022 |
| Abstract: SnSe has emerged as one of the most promising materials for thermoelectric energy conversion due to its extraordinary performance in its single-crystal form and its low-cost constituent elements. However, to achieve an economic impact, the polycrystalline counterpart needs to replicate the performance of the single crystal. Herein, we optimize the thermoelectric performance of polycrystalline SnSe produced by consolidating solution-processed and surface-engineered SnSe particles. In particular, the SnSe particles are coated with CdSe molecular complexes that crystallize during the sintering process, forming CdSe nanoparticles. The presence of CdSe nanoparticles inhibits SnSe grain growth during the consolidation step due to Zener pinning, yielding a material with a high density of grain boundaries. Moreover, the resulting SnSe–CdSe nanocomposites present a large number of defects at different length scales, which significantly reduce the thermal conductivity. The produced SnSe–CdSe nanocomposites exhibit thermoelectric figures of merit up to 2.2 at 786 K, which is among the highest reported for solution-processed SnSe. |
