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Alginate hydrogels possess properties analogous to those of the extracellular matrix (ECM). Thus, their mechanical behavior approximates soft tissue, which makes them desirable for the production of tissue-equivalent soft deformable structures. This study aims to determine the synthesis-structure-property relationship for alginate hydrogel with the Young's modulus in the range of 10°~101 kPa, mimicking to that of human lung tissue. Hydrogels, a 3D polymer network embedded in a water-rich environment. Homogeneous alginate hydrogels are synthesized by a direct mixture of sodium alginate and CaCO3, followed by the addition of D-glucono-δ-lactone (GDL) to initiate in-situ Ca2+ release and gelation. The influence of alginate concentration and molar ratio of the constituent calcium ion to carboxyl group from alginate monomer are evaluated while the Young's modulus of the hydrogel is carefully controlled within the desired range. FTIR and SEM are used to characterize the influence of synthesis parameters at the molecular and microstructure levels. Tension and compression testing are performed to determine the Young's modulus of the material. Empirical relations are established between synthesis parameters and the mechanical property. The result of the study will be subsequently used to guide the additive manufacturing of soft deformable structures based on alginate hydrogels. [ABSTRACT FROM AUTHOR]

Lung radiotherapy is greatly benefitted when the tumor motion caused by breathing can be modeled. The aim of this paper is to present the importance of using anisotropic and subject-specific tissue elasticity for simulating the airflow inside the lungs. A computational-fluid-dynamics (CFD) based approach is presented to simulate airflow inside a subject-specific deformable lung for modeling lung tumor motion and the motion of the surrounding tissues during radiotherapy. A flow-structure interaction technique is employed that simultaneously models airflow and lung deformation. The lung is modeled as a poroelastic medium with subject-specific anisotropic poroelastic properties on a geometry, which was reconstructed from four-dimensional computed tomography (4DCT) scan datasets of humans with lung cancer. The results include the 3D anisotropic lung deformation for known airflow pattern inside the lungs. The effects of anisotropy are also presented on both the spatiotemporal volumetric lung displacement and the regional lung hysteresis.

The influence of the method used for synthesizing ZnO-In2O3 composites (nanopowder mixing, impregnation, and hydrothermal method) on the structure, conductivity, and sensor properties is investigated. With the nanopowder mixing, the size of the parent nanoparticles in the composite remains practically unchanged in the range of 50–100 nm. The impregnation composites consist of 70 nm In2O3 nanoparticles with ZnO nanoclusters < 30 nm in size located on its surface. The nanoparticles in the hydrothermal composites have a narrow size distribution in the range of 10–20 nm. The specific surface of hydrothermal samples is five times higher than that of impregnated samples. The sensor response of the impregnated composite to 1100 ppm H2 is 1.3–1.5 times higher than the response of the mixed composite. Additives of 15–20 and 85 wt.% ZnO to mixed and impregnated composites lead to an increase in the response compared with pure In2O3. In the case of hydrothermal composite, up to 20 wt.% ZnO addition leads to a decrease in response, but 65 wt.% ZnO addition increases response by almost two times compared with pure In2O3. The sensor activity of a hydrothermal composite depends on the phase composition of In2O3. The maximum efficiency is reached for the composite containing cubic In2O3 and the minimum for rhombohedral In2O3. An explanation is provided for the observed effects. [ABSTRACT FROM AUTHOR]

The paper considers the relationship between the structure and properties of nanostructured conductometric sensors based on binary mixtures of semiconductor oxides designed to detect reducing gases in the environment. The sensor effect in such systems is determined by the chemisorption of molecules on the surface of catalytically active particles and the transfer of chemisorbed products to electron-rich nanoparticles, where these products react with the analyzed gas. In this regard, the role is evaluated of the method of synthesizing the composites, the catalytic activity of metal oxides (CeO2, SnO2, ZnO), and the type of conductivity of metal oxides (Co3O4, ZrO2) in the sensor process. The effect of oxygen vacancies present in the composites on the performance characteristics is also considered. Particular attention is paid to the influence of the synthesis procedure for preparing sensitive layers based on CeO2–In2O3 on the structure of the resulting composites, as well as their conductive and sensor properties. [ABSTRACT FROM AUTHOR]