Marine-Derived Actinomycetes: Biodegradation of Plastics and Formation of PHA Bioplastics-A Circular Bioeconomy Approach.

Plastics are present in the majority of daily-use products worldwide. Due to society's production and consumption patterns, plastics are accumulating in the environment, causing global pollution issues and intergenerational impacts. Our work aims to contribute to the development of solutions and sustainable methods to mitigate this pressing problem, focusing on the ability of marine-derived actinomycetes to accelerate plastics biodegradation and produce polyhydroxyalkanoates (PHAs), which are biodegradable bioplastics. The thin plastic films' biodegradation was monitored by weight loss, changes in the surface chemical structure (Infra-Red spectroscopy FTIR-ATR), and by mechanical properties (tensile strength tests). Thirty-six marine-derived actinomycete strains were screened for their plastic biodegradability potential. Among these, Streptomyces gougerotti, Micromonospora matsumotoense, and Nocardiopsis prasina revealed ability to degrade plastic films-low-density polyethylene (LDPE), polystyrene (PS) and polylactic acid (PLA) in varying conditions, namely upon the addition of yeast extract to the culture media and the use of UV pre-treated thin plastic films. Enhanced biodegradation by these bacteria was observed in both cases. S. gougerotti degraded 0.56% of LDPE films treated with UV radiation and 0.67% of PS films when inoculated with yeast extract. Additionally, N. prasina degraded 1.27% of PLA films when these were treated with UV radiation, and yeast extract was added to the culture medium. The main and most frequent differences observed in FTIR-ATR spectra during biodegradation occurred at 1740 cm-1, indicating the formation of carbonyl groups and an increase in the intensity of the bands, which indicates oxidation. Young Modulus decreased by 30% on average. In addition, S. gougerotti and M. matsumotoense, besides biodegrading conventional plastics (LDPE and PS), were also able to use these as a carbon source to produce degradable PHA bioplastics in a circular economy concept.

Water Molecular Dynamics in the Porous Structures of Ultrafiltration/Nanofiltration Asymmetric Cellulose Acetate-Silica Membranes.

This study presents the characterization of water dynamics in cellulose acetate-silica asymmetric membranes with very different pore structures that are associated with a wide range of selective transport properties of ultrafiltration (UF) and nanofiltration (NF). By combining 1H NMR spectroscopy, diffusometry and relaxometry and considering that the spin-lattice relaxation rate of the studied systems is mainly determined by translational diffusion, individual rotations and rotations mediated by translational displacements, it was possible to assess the influence of the porous matrix's confinement on the degree of water ordering and dynamics and to correlate this with UF/NF permeation characteristics. In fact, the less permeable membranes, CA/SiO2-22, characterized by smaller pores induce significant orientational order to the water molecules close to/interacting with the membrane matrix's interface. Conversely, the model fitting analysis of the relaxometry results obtained for the more permeable sets of membranes, CA/SiO2-30 and CA/SiO2-34, did not evidence surface-induced orientational order, which might be explained by the reduced surface-to-volume ratio of the pores and consequent loss of sensitivity to the signal of surface-bound water. Comparing the findings with those of previous studies, it is clear that the fraction of more confined water molecules in the CA/SiO2-22-G20, CA/SiO2-30-G20 and CA/SiO2-34-G20 membranes of 0.83, 0.24 and 0.35, respectively, is in agreement with the obtained diffusion coefficients as well as with the pore sizes and hydraulic permeabilities of 3.5, 38 and 81 kg h-1 m-2 bar-1, respectively, reported in the literature. It was also possible to conclude that the post-treatment of the membranes with Triton X-100 surfactants produced no significant structural changes but increased the hydrophobic character of the surface, leading to higher diffusion coefficients, especially for systems associated with average smaller pore dimensions. Altogether, these findings evidence the potential of combining complementary NMR techniques to indirectly study hydrated asymmetric porous media, assess the influence of drying post-treatments on hybrid CA/SiO2 membrane' surface characteristics and discriminate between ultra- and nano-filtration membrane systems.

Tuning the 1H NMR Paramagnetic Relaxation Enhancement and Local Order of [Aliquat]+-Based Systems Mixed with DMSO.

Understanding the behavior of a chemical compound at a molecular level is fundamental, not only to explain its macroscopic properties, but also to enable the control and optimization of these properties. The present work aims to characterize a set of systems based on the ionic liquids [Aliquat][Cl] and [Aliquat][FeCl4] and on mixtures of these with different concentrations of DMSO by means of 1H NMR relaxometry, diffusometry and X-ray diffractometry. Without DMSO, the compounds reveal locally ordered domains, which are large enough to induce order fluctuation as a significant relaxation pathway, and present paramagnetic relaxation enhancement for the [Aliquat][Cl] and [Aliquat][FeCl4] mixture. The addition of DMSO provides a way of tuning both the local order of these systems and the relaxation enhancement produced by the tetrachloroferrate anion. Very small DMSO volume concentrations (at least up to 1%) lead to enhanced paramagnetic relaxation without compromising the locally ordered domains. Larger DMSO concentrations gradually destroy these domains and reduce the effect of paramagnetic relaxation, while solvating the ions present in the mixtures. The paramagnetic relaxation was explained as a correlated combination of inner and outer-sphere mechanisms, in line with the size and structure differences between cation and anion. This study presents a robust method of characterizing paramagnetic ionic systems and obtaining a consistent analysis for a large set of samples having different co-solvent concentrations.

Designing silica xerogels containing RTIL for CO2 capture and CO2/CH4 separation: Influence of ILs anion, cation and cation side alkyl chain length and ramification.

CO2 separation from natural gas is considered to be a crucial strategy to mitigate global warming problems, meet product specification, pipeline specs and other application specific requirements. Silica xerogels (SX) are considered to be potential materials for CO2 capture due to their high specific surface area. Thus, a series of silica xerogels functionalized with imidazolium, phosphonium, ammonium and pyridinium-based room-temperature ionic liquids (RTILs) were synthesized. The synthesized silica xerogels were characterized by NMR, helium pycnometry, DTA-TG, BET, SEM and TEM. CO2 sorption, reusability and CO2/CH4 selectivity were assessed by the pressure-decay technique. Silica xerogels containing IL demonstrated advantages compared to RTILs used as separation solvents in CO2 capture processes including higher CO2 sorption capacity and faster sorption/desorption. Using fluorinated anion for functionalization of silica xerogels leads to a higher affinity for CO2 over CH4. The best performance was obtained by SX- [bmim] [TF2N] (223.4 mg CO2/g mg/g at 298.15 K and 20 bar). Moreover, SX- [bmim] [TF2N] showed higher CO2 sorption capacity as compared to other reported sorbents. CO2 sorption and CO2/CH4 selectivity results were submitted to an analysis of variance and the means compared using Tukey's test (5%).

Self-Determined Motivation and Competitive Anxiety in Athletes/Students: A Probabilistic Study Using Bayesian Networks.

This study attempts to analyze the relationship between two key psychological variables associated with performance in sports - Self-Determined Motivation and Competitive Anxiety - through Bayesian Networks (BN) analysis. We analyzed 674 university students that are athletes from 44 universities that competed at the University Games in Mexico, with an average age of 21 years (SD = 2.07) and with a mean of 8.61 years' (SD = 5.15) experience in sports. Methods: Regarding the data analysis, firstly, classification using the CHAID algorithm was carried out to determine the dependence links between variables; Secondly, a BN was developed to reduce the uncertainty in the relationships between the two key psychological variables. The validation of the BN revealed AUC values ranging from 0.5 to 0.92. Subsequently, various instantiations were performed with hypothetical values applied to the "bottom" variables. Results showed two probability trees that have extrinsic motivation and amotivation at the top, while the anxiety/activation due to worries about performance was at the bottom of the probabilities. The instantiations carried out support the existence of these probabilistic relationships, demonstrating their scarce influence on anxiety about competition generated by the intrinsic motivation, and the complex probabilistic effect of introjected and identified regulation regarding the appearance of anxiety due to worry about performance.

Spotting plants' microfilament morphologies and nanostructures.

The tracheary system of plant leaves is composed of a cellulose skeleton with diverse hierarchical structures. It is built of polygonally bent helical microfilaments of cellulose-based nanostructures coated by different layers, which provide them high compression resistance, elasticity, and roughness. Their function includes the transport of water and nutrients from the roots to the leaves. Unveiling details about local interactions of tracheary elements with surrounding material, which varies between plants due to adaptation to different environments, is crucial for understanding ascending fluid transport and for tracheary mechanical strength relevant to potential applications. Here we show that plant tracheary microfilaments, collected from Agapanthus africanus and Ornithogalum thyrsoides leaves, have different surface morphologies, revealed by nematic liquid crystal droplets. This results in diverse interactions among microfilaments and with the environment; the differences translate to diverse mechanical properties of entangled microfilaments and their potential applications. The presented study also introduces routes for accurate characterization of plants' microfilaments.

Reversible water driven chirality inversion in cellulose-based helices isolated from Erodium awns.

Among the movements observed in some cellulosic structures produced by plants are those that involve the dispersion and burial of seeds, as for example in Erodium from the Geraniaceae plant family. Here we report on a simple and efficient strategy to isolate and tune cellulose-based hygroscopic responsive materials from Erodium awns' dead tissues. The stimuli-responsive material isolated forms left-handed (L) or right-handed (R) helical birefringent transparent ribbons in the wet state that reversibly change to R helices when the material dries. The humidity-driven motion of dead tissues is most likely due to a composite material made of cellulose networks of fibrils imprinted by the plant at the nanoscale, which reinforces a soft wall polysaccharide matrix. The inversion of the handedness is explained using computational simulations considering filaments that contract and expand asymmetrically. The awns of Erodium are known to present hygroscopic movements, forming R helices in the dry state, but the possibility of actuating chirality via humidity suggests that these cellulose-based skeletons, which do not require complicated lithography and intricate deposition techniques, provide a diverse range of applications from intelligent textiles to micro-machines.

Novel coating containing molybdenum oxide nanoparticles to reduce Staphylococcus aureus contamination on inanimate surfaces.

We previously synthetized molybdenum oxide (MoO3) nanoparticles (NP) and showed their antibacterial activity against a representative collection of the most relevant bacterial species responsible for hospital-acquired infections, including Staphylococcus aureus. The aim of the present study was to prepare and characterize a novel coating with these MoO3 NP, confirm its mechanical stability, and investigate its biocidal effect to reduce S. aureus contamination on inanimate surfaces. In addition, the novel MoO3 NP coating was compared to a silver (Ag) NP coating synthetized by the same procedure. The MoO3 and Ag NP coatings were characterized in terms of their chemical structure by FT-IR, surface morphology by scanning electron microscopy, and mechanical properties by tensile and adhesion tests. The antimicrobial activity of the coatings was tested by following the loss of viability of S. aureus after 6h, 24h, 48h, and 72h exposure. MoO3 and Ag coatings exhibited surfaces of comparable morphologies and both presented elastomeric properties (tensile strength of ~420 kPa, Young's modulus of ~48 kPa, and maximum elongation of ~12%), and excellent (classification of 5B) adhesion to glass, steel and polystyrene surfaces. The two coatings exhibited a good antibacterial activity (R) against S. aureus over time (RMoO3 = 0.2-0.81; RAg = 0.61-2.37), although the effect of the Ag NP coating was more pronounced, especially at 72h (RMoO3 = 0.81 vs RAg = 2.37). Noteworthy, contrary to the Ag NP coating, the MoO3 NP coating was colourless and transparent, avoiding undesired unaesthetic effects. The synthetized coating with NP of MoO3, which has low toxicity to humans, capability of biodegradation, and rapid excretion, can be applied onto most standard materials and therefore is a promising tool to reduce S. aureus contamination on usual inanimate surfaces found in healthcare and community environments.

Bacterial cellulose: a versatile biopolymer for wound dressing applications.

Although several therapeutic approaches are available for wound and burn treatment and much progress has been made in this area, room for improvement still exists, driven by the urgent need of better strategies to accelerate wound healing and recovery, mostly for cases of severe burned patients. Bacterial cellulose (BC) is a biopolymer produced by bacteria with several advantages over vegetal cellulose, such as purity, high porosity, permeability to liquid and gases, elevated water uptake capacity and mechanical robustness. Besides its biocompatibility, BC can be modified in order to acquire antibacterial response and possible local drug delivery features. Due to its intrinsic versatility, BC is the perfect example of a biotechnological response to a clinical problem. In this review, we assess the BC main features and emphasis is given to a specific biomedical application: wound dressings. The production process and the physical-chemical properties that entitle this material to be used as wound dressing namely for burn healing are highlighted. An overview of the most common BC composites and their enhanced properties, in particular physical and biological, is provided, including the different production processes. A particular focus is given to the biochemistry and genetic manipulation of BC. A summary of the current marketed BC-based wound dressing products is presented, and finally, future perspectives for the usage of BC as wound dressing are foreseen.

Electrical properties of a liquid crystal dispersed in an electrospun cellulose acetate network.

Electro-optical devices that work in a similar fashion as PDLCs (polymer-dispersed liquid crystals), produced from cellulose acetate (CA) electrospun fibers deposited onto indium tin oxide coated glass and a nematic liquid crystal (E7), were studied. CA and the CA/liquid crystal composite were characterized by multiple investigation techniques, such as polarized optical microscopy, dielectric spectroscopy and impedance measurements. Dielectric constant and electric energy loss were studied as a function of frequency and temperature. The activation energy was evaluated and the relaxation time was obtained by fitting the spectra of the dielectric loss with the Havriliak-Negami functions. To determine the electrical characteristics of the studied samples, impedance measurements results were treated using the Cole-Cole diagram and the three-element equivalent model.

Cellulose-Based Biomimetics and Their Applications.

Nature has been producing cellulose since long before man walked the surface of the earth. Millions of years of natural design and testing have resulted in cellulose-based structures that are an inspiration for the production of synthetic materials based on cellulose with properties that can mimic natural designs, functions, and properties. Here, five sections describe cellulose-based materials with characteristics that are inspired by gratings that exist on the petals of the plants, structurally colored materials, helical filaments produced by plants, water-responsive materials in plants, and environmental stimuli-responsive tissues found in insects and plants. The synthetic cellulose-based materials described herein are in the form of fibers and films. Fascinating multifunctional materials are prepared from cellulose-based liquid crystals and from composite cellulosic materials that combine functionality with structural performance. Future and recent applications are outlined.

1H NMR Relaxometry and Diffusometry Study of Magnetic and Nonmagnetic Ionic Liquid-Based Solutions: Cosolvent and Temperature Effects.

In this work, 1H NMR relaxometry and diffusometry as well as viscometry experiments were carried out as a means to study the molecular dynamics of magnetic and nonmagnetic ionic liquid-based systems. In order to evaluate the effect of a cosolvent on the superparamagnetic properties observed for Aliquat-iron-based magnetic ionic liquids, mixtures comprising different concentrations, 1% and 10% (v/v), of DMSO-d6 were prepared and studied. The results for both magnetic and nonmagnetic systems were consistently analyzed an suggest that, when at low concentrations, DMSO-d6 promotes more structured ionic arrangements, thus enhancing these superparamagnetic properties. Furthermore, the analysis of temperature and water concentration effects allowed to conclude that neither one of these variables significantly affected the superparamagnetic properties of the studied magnetic ionic liquids.

Mind the Microgap in Iridescent Cellulose Nanocrystal Films.

A new photonic structure is produced from cellulose nanocrystal iridescent films reflecting both right and left circularly polarized light. Micrometer-scale planar gaps perpendicular to the films' cross-section between two different left-handed films' cholesteric domains are impregnated with a nematic liquid crystal. This photonic feature is reversibly tuned by the application of an electric field or a temperature variation.

Sensing and tuning microfiber chirality with nematic chirogyral effect.

Microfibers with their elongated shape and translation symmetry can act as important components in various soft materials, notably for their mechanics on the microscopic level. Here we demonstrate the mechanical response of a micro-object to imposed chirality, in this case, the tilt of disclination rings in an achiral nematic medium caused by the chiral surface anchoring on an immersed microfiber. This coupling between chirality and mechanical response, used to demonstrate sensing of chirality of electrospun cellulose microfibers, is revealed in the optical micrographs due to anisotropy in the elastic response of the host medium. We provide an analytical explanation of the chirogyral effect supported with numerical simulations and perform an experiment to test the effect of the cell confinement and fiber size. We controllably twist the microfibers and demonstrate the response of the nematic medium. More generally the demonstrated study provides means for experimental discrimination of surface properties and allows mechanical control over the shape of disclination rings.

Sensing surface morphology of biofibers by decorating spider silk and cellulosic filaments with nematic microdroplets.

Probing the surface morphology of microthin fibers such as naturally occurring biofibers is essential for understanding their structural properties, biological function, and mechanical performance. The state-of-the-art methods for studying the surfaces of biofibers are atomic force microscopy imaging and scanning electron microscopy, which well characterize surface geometry of the fibers but provide little information on the local interaction potential of the fibers with the surrounding material. In contrast, complex nematic fluids respond very well to external fields and change their optical properties upon such stimuli. Here we demonstrate that liquid crystal droplets deposited on microthin biofibers--including spider silk and cellulosic fibers--reveal characteristics of the fibers' surface, performing as simple but sensitive surface sensors. By combining experiments and numerical modeling, different types of fibers are identified through the fiber-to-nematic droplet interactions, including perpendicular and axial or helicoidal planar molecular alignment. Spider silks align nematic molecules parallel to fibers or perpendicular to them, whereas cellulose aligns the molecules unidirectionally or helicoidally along the fibers, indicating notably different surface interactions. The nematic droplets as sensors thus directly reveal chirality of cellulosic fibers. Different fiber entanglements can be identified by depositing droplets exactly at the fiber crossings. More generally, the presented method can be used as a simple but powerful approach for probing the surface properties of small-size bioobjects, opening a route to their precise characterization.

Carbon Nanotubes as Reinforcement of Cellulose Liquid Crystalline Responsive Networks.

The incorporation of small amount of highly anisotropic nanoparticles into liquid crystalline hydroxypropylcellulose (LC-HPC) matrix improves its response when is exposed to humidity gradients due to an anisotropic increment of order in the structure. Dispersed nanoparticles give rise to faster order/disorder transitions when exposed to moisture as it is qualitatively observed and quantified by stress-time measurements. The presence of carbon nanotubes derives in a improvement of the mechanical properties of LC-HPC thin films.

Relationships between cooperation and goal orientation among male professional and semi-professional team athletes.

In team sports, athletes' goals may focus on the task (enhancing performance, developing better skills, etc.) or on ego (being better than the others, achieving superiority, etc.). This study investigated the relationships between athletes' goal orientation and their tendency to cooperate with teammates and coaches. 158 professional men (M age = 24.1 yr., SD = 4.6) who played on various sport teams participated in this study. Goal orientation was measured with the Portuguese version of the Task and Ego Orientation in Sport Questionnaire, and cooperation was measured with the Questionário de Cooperação Desportiva. Cooperation was positively correlated with task orientation, and negatively correlated with ego orientation. Overall, the findings support that in sports, directing the players' focus on task may promote prosocial behavior.