Hydrogel Encapsulation of Mesenchymal Stem Cells and Their Derived Exosomes for Tissue Engineering

Tissue engineering has been an inveterate area in the field of regenerative medicine for several decades. However, there remains limitations to engineer and regenerate tissues. Targeted therapies using cell-encapsulated hydrogels, such as mesenchymal stem cells (MSCs), are capable of reducing inflammation and increasing the regenerative potential in several tissues. In addition, the use of MSC-derived nano-scale secretions (i.e., exosomes) has been promising. Exosomes originate from the multivesicular division of cells and have high therapeutic potential, yet neither self-replicate nor cause auto-immune reactions to the host. To maintain their biological activity and allow a controlled release, these paracrine factors can be encapsulated in biomaterials. Among the different types of biomaterials in which exosome infusion is exploited, hydrogels have proven to be the most user-friendly, economical, and accessible material. In this paper, we highlight the importance of MSCs and MSC-derived exosomes in tissue engineering and the different biomaterial strategies used in fabricating exosome-based biomaterials, to facilitate hard and soft tissue engineering.     

The non-stationary response of flexible pavements to moving loads

In this paper, the pavement surface deterioration is investigated based on field measurements of surface roughness profiles obtained in Sweden. A predictive function for surface deterioration, based on average gradient of yearly measurements of the road surface profile in Swedish road network, is proposed. In order to characterise the dynamic loads induced on the pavement by moving traffic a quarter car model is used. Afterwards a non-stationary stochastic approach is used to obtain the yearly response of the pavement to moving loads. The solution is in frequency–wavenumber domain and is given for a non-stationary random case as the pavement surface deteriorates in pavement service life thus influencing the magnitude of the dynamic loads induced by the vehicles. The effect of pavement surface evolution on the stress state induced in the pavement by moving traffic is examined for a specific case of quarter car model and pavement structure. The results showed approximately a 100% increase in the dynamic component of stresses induced in the pavement.     

Navigation your way: from spontaneous independent exploration to dynamic social journeys

In this article, we describe a novel approach to pedestrian navigation using bearing-based haptic feedback. People are guided in the general direction of their destination via a minimal directional cue, but additional exploration is stimulated by varying feedback based on the potential for taking alternative routes. This extreme navigation method removes the complexities of maps and direction following, concentrating on allowing pedestrians to actively explore their surroundings, rather than offering perfect, but passive, turn-by-turn guidance. We simulate and build two mobile prototypes to examine the possible benefits of this approach, then further extend its impact by considering how social media might be incorporated to provide a real-time, dynamically evolving map of physical locations. The successful use of our mobile prototypes is demonstrated in a realistic field trial, and we discuss the results and interesting participant behaviours that were recorded, validating the predictions from their earlier simulation. We continue by simulating the use of publicly posted status updates and pictures as a proxy for location mapping, showing how these methods can produce comparable navigation results to real-world field trials, highlighting their potential as tools for real-world social journeys.     

A hierarchical hybrid of ZnCo2O4 and rGO as a significant electrocatalyst for methanol oxidation reaction: Synthesis,characterization, and electrocatalytic performance

Hierarchical porous ZnCo₂O₄ nanosheets and ZnCo₂O₄-coated reduced graphene oxide (ZnCo₂O₄/rGO) were synthesized by the hydrothermal method followed by the annealing process. The composition of materials was proved by X-ray electron spectroscopy and X-ray photoelectron spectroscopy. The size and morphology of the as-prepared samples were evaluated by scanning electron microscopy and transmission electron microscopy. The result showed ZnCo₂O₄ nanosheets with porous morphology and a sheet thickness of about 5 nm was well synthesized. The electrochemical tests used to prove the catalytic performance of the prepared catalysts were cyclic voltammetry and impedance spectroscopy, and the analysis was performed in alkaline environments. The electrochemical investigations on ZnCo₂O₄ and ZnCo₂O₄/rGO showed the rGO has an effective role in electrooxidation of methanol in alkaline media. In addition to the synergic effect between Zn and Co, the synergistic effect between ZnCo₂O₄ (make active sites for adsorption of methanol) and rGO (provide more conductivity and make more sites by preventing from the agglomeration of ZnCo₂O₄) has an important role for this excellent performance. The polarization curves of ZnCo₂O₄/rGO showed a maximum power density of 24.3 mW cm⁻², which proved its potential capability for the direct methanol fuel cell.     

A cloud-based platform to ensure interoperability in aerospace industry

A new approach is proposed to address several key issues relating to interoperability for collaborative product development within networked organizations. The work innovatively combines (i) a two-phase semantic data mediation model to ensure interoperability, (ii) a cloud-based platform to enable complex collaboration scenarios and (iii) an implementation and the evaluation of the proposed approach in the aerospace industry. The latter demonstrates that data mediation delivered as a service drastically reduces cost and time needed for establishing and maintaining interoperability.     

Influence of substrate temperature on structural and optical properties of RF sputtered ZnMnO thin films

The ZnMnO thin films were deposited on glass substrates by radio frequency magnetron sputtering method. The properties of ZnMnO thin films were investigated by high-resolution x-ray diffractometer (HRXRD),atomic force microscopy (AFM), UV-Vis spectrometer and room temperature photoluminescence (PL), under the influence of substrate temperature. The substrate temperature was varied from 300, 400 and 500°C. With increasing the substrate temperature, the structure of the films changed from cubic to hexagonal. The cubic ZnMnO thin films grown along [210] direction, while the hexagonal ones grown along [002] direction. The changes in surface morphology provided a proof on the structural transition. Also, decrease and increase of optical band gap is associated with cubic or hexagonal structure of the films.

     

Electrocatalytic oxidation of hydrazine at a Co(II) complex multi-wall carbon nanotube modified carbon paste electrode

The catalytic oxidation of hydrazine was investigated by a cobalt(II) bis (benzoylacetone) ethylenediimino multi wall carbon nanotube-modified carbon paste electrode (Co(II)BBAEDI-MWCNT-MCPE) as a highly sensitive electrochemical sensor. The effect of variables such as pH and modifier percent on cyclic voltammograms peak current was optimized. The modified electrode showed very efficient electrocatalytic activity for anodic oxidation of hydrazine in 0.1 M phosphate buffer solution (pH 7.0). Anodic peak potential of hydrazine oxidation at the surface of modified electrode shifts by about 500 mV toward negative values compared with that on the bare electrode. The diffusion coefficient and electron transfer coefficient of hydrazine were obtained using electrochemical approaches. The Co(II)BBAEDI-MWCNT-MCPE showed good reproducibility (RSD < 3.3%). The electrocatalytic current increased linearly with the hydrazine concentration in the range of 0.3–70.0 μM and detection limit was 0.1 μM. The effect of various interferences on the hydrazine peak current was studied. This method was applied to determine hydrazine in water samples.     

Tailoring interfacial adhesion and mechanical performance of biocomposites based on poly(lactic acid)/rice straw by using maleic anhydride through reactive extrusion process

In this study, all-green biocomposites based on poly(lactic acid) (PLA)/rice straw (RS) as an agricultural waste were prepared, and the physical, structural, and mechanical properties of these biocomposites were enhanced by alkali-pulping of RS and chemical grafting of PLA onto the lignocellulosic fiber. The reactive compatibilizers of maleic anhydride grafted PLA (PLA-g-MA) were obtained through a reactive extrusion process at different processing conditions. The probable chemical reactions between the functional groups of PLA-g-MA with hydroxyl groups of RS pulp as well as the end groups of PLA chains can effectively improve the interfacial adhesion between the filler and matrix. However, the findings confirm the great importance of PLA-g-MA chemical structure in controlling the biocomposite performance. By choosing proper processing conditions for preparing PLA-g-MA and incorporating this compatibilizer into the PLA/treated RS biocomposite, Young modulus, tensile strength, impact strength, and tensile toughness of the PLA/RS biocomposite increased by 101%, 156%, 96%, and 327%, respectively.