Functional biohybrid materials based on halloysite, sepiolite and cellulose nanofibers for health applications

Multicomponent nanopaper from the assembly of nanotubular halloysite, microfibrous sepiolite and cellulose nanofibers was developed for diverse functional applications such as slow release of antibacterial model drugs loaded into halloysite lumen

Metformin and temozolomide, a synergic option to overcome resistance in glioblastoma multiforme models

Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor with poor survival. Cytoreduction in association with radiotherapy and temozolomide (TMZ) is the standard therapy, but response is heterogeneous and life expectancy is limited. The combined use of chemotherapeutic agents with drugs targeting cell metabolism is becoming an interesting therapeutic option for cancer treatment. Here, we found that metformin (MET) enhances TMZ effect on TMZ-sensitive cell line (U251) and overcomes TMZ-resistance in T98G GBM cell line. In particular, combined-treatment modulated apoptosis by increasing Bax/Bcl-2 ratio, and reduced Reactive Oxygen Species (ROS) production. We also observed that MET associated with TMZ was able to reduce the expression of glioma stem cells (GSC) marker CD90 particularly in T98G cells but not that of CD133. In vivo experiments showed that combined treatment with TMZ and MET significantly slowed down growth of TMZ-resistant tumors but did not affect overall survival of TMZ-sensitive tumor bearing mice. In conclusion, our results showed that metformin is able to enhance TMZ effect in TMZ-resistant cell line suggesting its potential use in TMZ refractory GBM patients. However, the lack of effect on a GBM malignancy marker like CD133 requires further evaluation since it might influence response duration

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Facilitating development of special clays by Machine Learning techniques

The initial sections of Chapter 1 introduce the main goal of this Industrial PhD Thesis and offer an insight on the physico-chemical properties of special clays and their main application fields that are specifically targeted throughout this PhD thesis. The State-of-the-art for machine learning tools in porous materials is also discussed. The latter includes an overview of the datasets, descriptors, and methodology . Chapter 2 presents this thesis's achievements, giving a general discussion of the three research articles published within this PhD work. The discussion also discloses a novel practice of machine learning models in capturing the synergy between compounds, which is related to the works of Chapters 4 and 5. The latter is expanded in Annex 1 and is expected to be converted into an additional research publication in the future. A resume of the work realized during the International stay is given and thoroughly presented in Chapter 6. Chapter 3 includes the "Machine-Learning-Accelerated Multimodal Characterization and Multiobjective Design Optimization of Natural Porous Materials" article published in Chemical Science journal. The contribution demonstrates the first application of machine learning to predict the morphology and surface activity of natural and modified clay-based materials. The suitable proposed material representation allowed us to build predictive algorithms which can be exploited in the design of clay-based acid nanocatalysts. Chapter 4 moves to "Machine learning-aided design of composite mycotoxin detoxifier material for animal feed", published in Scientific Reports journal. Random forest was educated by a historical set of in vitro adsorption data to screen and identify the optimal formulation. The latter was directly tested in an in vivo trial in collaboration with the Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine of Ghent University. Chapter 5 presents the advantages of coupling the advanced design of experiment tools to machine learning in the context of rheological additive design. The work was presented in the article Datadriven experimental design of rheological clay-polymer composites, published in the Industrial & Engineering Chemistry Research journal. The diversity selection algorithm was arranged to identify formulations correlated to the most different outcomes. Three top promising composites were then prepared and tested in their rheological behavior, validating the proposed approach. Chapter 6 demonstrated the achievements of the work done in collaboration with the Department of Physics and Chemistry of the University of Palermo during my International stay. The work was completed by running additional experiments in Tolsa laboratories, and the whole story was converted into a manuscript and recently submitted to Microporous and Mesoporous Materials. By using modulated thermogravimetric analysis, the behavior of confined water on the structures of five diverse clays was deeply investigated. The latter allowed us to calculate the activation energy for the removal of the adsorbed water (Ea) and correlate it to adsorption properties. Annex 1 presents an extension of the use of machine learning models in capturing the synergy between components of nanocomposites. The concept was first explored during the development of the work published and reported in Chapter 4. The predictions of the mycotoxin adsorption followed a non-linear regression within a linear combination of the compounds in the detoxifier formulation. The latter was associated with the ability of machine learning models to consider the synergy between those compounds. The approach was then applied to the work reported in Chapter 5, observing similar behavior. The results will be adapted as a manuscript to be published as a research contribution.Programa de Doctorado en Ciencia e Ingeniería de Materiales por la Universidad Carlos III de MadridPresidente: Miguel Ángel Bañares.- Secretario: Diego Martínez del Olmo.- Vocal: Rocío Mercad

Machine learning-aided design of composite mycotoxin detoxifier material for animal feed

The development of food and feed additives involves the design of materials with specific properties that enable the desired function while minimizing the adverse effects related with their interference with the concurrent complex biochemistry of the living organisms. Often, the development process is heavily dependent on costly and time-consuming in vitro and in vivo experiments. Herein, we present an approach to design clay-based composite materials for mycotoxin removal from animal feed. The approach can accommodate various material compositions and different toxin molecules. With application of machine learning trained on in vitro results of mycotoxin adsorption–desorption in the gastrointestinal tract, we have searched the space of possible composite material compositions to identify formulations with high removal capacity and gaining insights into their mode of action. An in vivo toxicokinetic study, based on the detection of biomarkers for mycotoxin-exposure in broilers, validated our findings by observing a significant reduction in systemic exposure to the challenging to be removed mycotoxin, i.e., deoxynivalenol (DON), when the optimal detoxifier is administrated to the animals. A mean reduction of 32% in the area under the plasma concentration–time curve of DON-sulphate was seen in the DON + detoxifier group compared to the DON group (P = 0.010)

Thermogravimetric Analysis of Moisture in Natural and Thermally Treated Clay Materials

Clays are a class of porous materials; their surfaces are naturally covered by moisture. Weak thermal treatment may be considered practical to remove the water molecules, changing the surface properties and making the micro- and/or mesoporosities accessible to interact with other molecules. Herein, a modulated thermogravimetric analysis (MTGA) study of the moisture behavior on the structures of five, both fibrous and laminar, clay minerals is reported. The effect of the thermal treatment at 150 °C, which provokes the release of weakly adsorbed water molecules, was also investigated. The activation energies for the removal of the adsorbed water (Ea) were calculated, and they were found to be higher, namely, from 160 to 190 kJ mol-1, for fibrous clay minerals compared to lamellar structures, ranging in this latter case from 80 to 100 kJ mol-1. The thermal treatment enhances the rehydration in Na-montmorillonite, stevensite, and sepiolite structures with a decrease in the energy required to remove it, while Ea increases significantly in palygorskite (from 164 to 273 kJ mol-1). As a proof of concept, the MTGA results are statistically correlated, together with a full characterization of the physico-chemical properties of the five clay minerals, with the adsorption of two molecules, i.e., aflatoxin B1 (AFB1) and β-carotene. Herein, the amount of adsorbed molecules ranges from 12 to 97% for the former and from 22 to 35% for the latter, depending on the particular clay. The Ea was correlated with AFB1 adsorption with a Spearman score of -0.9. When the adsorbed water is forcibly removed, e.g., under vacuum conditions and high temperatures, the structure becomes the most important, decreasing the Spearman score between β-carotene and Ea to -0.6

Stato e Regioni nella politica per il contenimento della spesa per la crescita

Il volume intende analizzare le politiche statali e regionali per il contenimento della spesa per la crescit

Multicomponent bionanocomposites based on clay nanoarchitectures for electrochemical devices

[EN] Based on the unique ability of defibrillated sepiolite (SEP) to form stable and homogeneous colloidal dispersions of diverse types of nanoparticles in aqueous media under ultrasonication, multicomponent conductive nanoarchitectured materials integrating halloysite nanotubes (HNTs), graphene nanoplatelets (GNPs) and chitosan (CHI) have been developed. The resulting nanohybrid suspensions could be easily formed into films or foams, where each individual component plays a critical role in the biocomposite: HNTs act as nanocontainers for bioactive species, GNPs provide electrical conductivity (enhanced by doping with MWCNTs) and, the CHI polymer matrix introduces mechanical and membrane properties that are of key significance for the development of electrochemical devices. The resulting characteristics allow for a possible application of these active elements as integrated multicomponent materials for advanced electrochemical devices such as biosensors and enzymatic biofuel cells. This strategy can be regarded as an >a la carte> menu, where the selection of the nanocomponents exhibiting different properties will determine a functional set of predetermined utility with SEP maintaining stable colloidal dispersions of different nanoparticles and polymers in water.The authors thank the MINECO (project MAT2015-71117-R) for financial support. GLD and LL acknowledge the University of Palermo for the “UOB21 Borse di studio finalizzate alla ricerca” grants. BW thanks the MINECO for an IJCI contract (IJCI-2015-23886). The authors also thank Dr. M. Darder, Dr. M. L. Ferrer, and Dr. N. López-Salas for fruitful discussions on bioelectrocatalysis

Functional biohybrid materials based on halloysite, sepiolite and cellulose nanofibers for health applications

Biohybrid materials were prepared by co-assembling the three following components: nanotubular halloysite, microfibrous sepiolite, and cellulose nanofibers dispersed in water, in order to exploit the most salient features of each individual component and to render homogeneous, flexible, yet strong films. Indeed, the incorporation of halloysite improves the mechanical performance of the resulting hybrid nanopapers and the assembly of the three components modifies the surface features concerning wetting properties compared to pristine materials, so that the main characteristics of the resulting materials become tunable with regard to certain properties. Owing to their hierarchical porosity together with their diverse surface characteristics, these hybrids can be used in diverse biomedical/pharmaceutical applications. Herein, for instance, loading with two model drugs, salicylic acid and ibuprofen, allows controlled and sustained release as deduced from antimicrobial assays, opening a versatile path for developing other related organic-inorganic materials of potential interest in diverse application fields.The authors thank the MINECO (Spain) and FEDER (EU) for financial support (project MAT2015-71117-R). LL and GDL acknowledge the University of Palermo for the “UOB21 Borse di studio finalizzate alla ricerca” grants. BW thanks the MINECO for the IJCI contract (IJCI-2015-23886). We acknowledge support of the publication fee by the CSIC Open Access Support Initiative through its Unit of Information Resources for Research (URICI

Sepiolite-Hydrogels: Synthesis by Ultrasound Irradiation and Their Use for the Preparation of Functional Clay-Based Nanoarchitectured Materials

International audienceSepiolite and palygorskite fibrous clay minerals are 1D silicates featuring unique textural and structural characteristics useful in diverse applications, and in particular as rheological additives. Here we report on the ability of grinded sepiolite to generate highly viscous and stable hydrogels by sonomechanical irradiation (ultrasounds). Adequate drying of such hydrogels leads to low-density xerogels that show extensive fiber disaggregation compared to the starting sepiolite-whose fibers are agglomerated as bundles. Upon re-dispersion in water under high-speed shear, these xerogels show comparable rheological properties to commercially available defibrillated sepiolite products, resulting in high viscosity hydrogels that minimize syneresis. These colloidal systems are thus very interesting as they can be used to stabilize many diverse compounds as well as nano-/ micro-particles, leading to the production of a large variety of composites and nano/microarchitectured solids. In this context, we report here various examples showing how colloidal routes based on sepiolite hydrogels can be used to obtain new heterostructured functional materials, based on their assembly to solids of diverse topology and composition such as 2D and 1D kaolinite and halloysite aluminosilicates, as well as to the 2D synthetic Mg,Al-layered double hydroxides (LDH)