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Although adhesive interactions between cells and nanostructured interfaces have been studied extensively, there is a paucity of data on how nanostructured interfaces repel cells by directing cell migration and cell-colony organization. Here, by using multiphoton ablation lithography to pattern surfaces with nanoscale craters of various aspect ratios and pitches, we show that the surfaces altered the cells' focal-adhesion size and distribution, thus affecting cell morphology, migration and ultimately localization. We also show that nanocrater pitch can disrupt the formation of mature focal adhesions to favour the migration of cells towards higher-pitched regions, which present increased planar area for the formation of stable focal adhesions. Moreover, by designing surfaces with variable pitch but constant nanocrater dimensions, we were able to create circular and striped cellular patterns. Our surface-patterning approach, which does not involve chemical treatments and can be applied to various materials, represents a simple method to control cell behaviour on surfaces. [ABSTRACT FROM AUTHOR]

Abstract: A human in vitro cardiac tissue model would be a significant advancement for understanding, studying, and developing new strategies for treating cardiac arrhythmias and related cardiovascular diseases. We developed an in vitro model of three-dimensional (3D) human cardiac tissue by populating synthetic filamentous matrices with cardiomyocytes derived from healthy wild-type volunteer (WT) and patient-specific long QT syndrome type 3 (LQT3) induced pluripotent stem cells (iPS-CMs) to mimic the condensed and aligned human ventricular myocardium. Using such a highly controllable cardiac model, we studied the contractility malfunctions associated with the electrophysiological consequences of LQT3 and their response to a panel of drugs. By varying the stiffness of filamentous matrices, LQT3 iPS-CMs exhibited different level of contractility abnormality and susceptibility to drug-induced cardiotoxicity. [Copyright &y& Elsevier]

Systems existing in nature have evolved to operate efficiently over a long period of time, enabling efficient material transformation and processing. These natural systems provide hints for the synthesis of metal nanoparticles through efficient electron generation and transport towards metal ions for the reduction process. In this study, based on the efficient electron transfer mechanism between tryptophan (Trp) in the living body, the possibility of advanced silver patterning on flexible substrates has been presented through laser-direct writing. Irradiation of a low-power laser on the precursor induces the reduction of silver ions to nanoparticles. The sintering of these generated nanoparticles induces a silver conductive pattern by a photothermal/chemical reaction. The method of this study has strength as it supports the possibility of conductive pattern fabrication on various substrates (e.g., glass and PDMS) using a silver-based organic ink with low laser power compared to the conventional nanoparticle-based sintering method. It also suggests its suitability to various applications in terms of sophisticated pattern fabrication with minimized substrate denaturation. [ABSTRACT FROM AUTHOR]

Analyses of images of the cell-to-substratum region of contact have been carried out by the means of total internal reflection fluorescence (TIRF) microscopy during both the formation and the dissolution of cellular contacts. The evolutions of the cellular contacts are visualized during the adhesion process under normal and virus-infected intracellular conditions, and during the lift-off process under various toxicities of the extracellular medium fluid. Then, propositions are developed for quantifying the cell viabilities by estimating the increase in the area of contact for the adhesion process and by specifying the maximum intensity of the TIRF image for the lift-off process. [ABSTRACT FROM AUTHOR]

• Epitaxial SiGe fin layers were selectively grown in sub-100 nm oxide trench arrays. • Three fin structures were found for the layers with Ge content in the observed range. • The each growth rate of appeared facet surfaces changes the type of fin structures. • Facet evolutions were consistent with the results obtained for three blanket layers. We selectively grew epitaxial Si 1− x Ge x fin layers with x in the range of 0.36–0.63 in oxide trench arrays with trench width of 40, 65, and 90 nm. The dominant facet of the Si 1− x Ge x layers changed from {1 1 1} to {1 1 3} at x = 0.56, and three types of facets were found for the layers with Ge content in the observed range. The relationship between the facet evolution and the growth rate of the facets was investigated. Blanket Si 1− x Ge x layers grown on three substrates with orientations of (0 0 1), (1 1 1), and (1 1 3) were used for comparing the growth rate of each facet during the facet evolution. The results obtained for the blanket layers were found to be consistent with the facet evolutions in the Si 1− x Ge x fin layers with Ge content in the range of 0.36–0.63. [ABSTRACT FROM AUTHOR]

We examined the selective epitaxial growth of Ge on Si(001) substrates with 40, 65, and 90 nm width trench arrays by ultra-high vacuum chemical vapor deposition. Because SiO 2 trench walls were present, no surface undulation in the direction parallel to the trenches was observed and compressive strain developed in the same direction. Based on reciprocal space mapping (RSM) measurements, this strain along the parallel direction increased from − 0.28 to − 0.72% as the width of the exposed Si substrate between the SiO 2 walls decreased from 90 to 40 nm, which was due to a decrease in strain relaxation. We calculated the effect of the Si trench width on changes in strain after removing the SiO 2 walls and compared the calculated values with the RSM results. No significant change in the strain relaxation was detected along the direction perpendicular to the trenches, and the strain changes were < 0.1%. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the growth of the epitaxial Ge layers in a 40nm wide SiO2 trench array on Si by ultra-high vacuum chemical vapor deposition. If the thickness of Ge was less than the height of the SiO2 trenches, the Ge layers grew epitaxially by a selective epitaxial growth process without any detectable surface modification, which is due to the high interfacial energy between the SiO2 mask and Ge. We calculated the critical strain required to modify the Ge surface via 3-dimensional island transition (the minimum strain) as a function of the trench width. Considering the energies involved in the transition, we found that uniformly shaped Ge layers along the trenches were energetically more favorable than those with surface undulations as the width of the trench decreased. The strained Ge epilayers relaxed their energy by forming the defects, such as dislocations at the Ge/Si interfaces and stacking faults. From the strain analyses, the residual strains for parallel and perpendicular to the trench direction in the Ge layers were −0.72% and −0.22%, respectively. [Copyright &y& Elsevier]

• The stainless steel modified surface was fabricated for chevron plate heat exchanger. • The anti-fouling performance would be estimated on bare, modified, PMMA and BN coated. • The dynamic wetting characteristics could be possible to explain the anti-fouling performance. In this study, we aimed to develop a method for modifying SUS304 with micro/nanoscale holes using an electrical etching technique, and evaluated its impact on the anti-fouling performance of chevron plate heat exchangers. The modified SUS304 specimen exhibited hydrophobic wetting characteristics; however, water droplets stuck to the wall under inclined orientations at angles of 30° and 60°. We coated the modified SUS304 specimen with polymer (polymethyl methacrylate; PMMA) and hexagonal boron nitride (BN) particles to realize the hydrophobic and superhydrophobic wetting characteristics. To evaluate the anti-fouling performance of the heat exchanger, we carried out fouling acceleration experiments in a 2000 ppm CaCO 3 solution for 2 h. The anti-fouling performance was determined by measuring the overall heat transfer coefficients during fouling acceleration experiments. As the operation time increased, the CaCO 3 particles were deposited on the surface of the heat exchanger, the overall heat transfer coefficient decreased, and the fouling factor ultimately increased. Out of bare, modified, PMMA- and BN-coated heat exchangers, the PMMA-coated heat exchanger exhibited the strongest anti-fouling performance, with the lowest increment in the fouling factor. Based on analysis of the contact angle hysteresis (CAH) in each case, we suggest that CaCO 3 particles in solution would be deposited better in the case of the highest CAH. This is possible in cases without the triple contact line, and is caused by filling the polymer into micro/nano holes on the modified surface. [ABSTRACT FROM AUTHOR]

As novel technologies have been developed, emissions of gases of volatile organic compounds (VOCs) have increased. These affect human health and are destructive to the environment, contributing to global warming. Hence, regulations on the use of volatile organic compounds have been strengthened. Therefore, powerful adsorbents are required for volatile organic compounds gases. In this study, we used graphene powder with a mesoporous structure to adsorb aromatic compounds such as toluene and xylene at various concentrations (30, 50, 100 ppm). The configuration and chemical composition of the adsorbents were characterized using scanning electron microscopy (SEM), N2 adsorption-desorption isotherm measurements, and X-ray photoelectron spectroscopy (XPS). The adsorption test was carried out using a polypropylene filter, which contained the adsorbents (0.25 g), with analysis performed using a gas detector. Compared to graphite oxide (GO) powder, the specific surface area of thermally expanded graphene powder (TEGP800) increased significantly, to 542 m2 g−1, and its chemical properties transformed from polar to non-polar. Thermally expanded graphene powder exhibits high adsorption efficiency for toluene (92.7–98.3%) and xylene (96.7–98%) and its reusability is remarkable, being at least 91%. [ABSTRACT FROM AUTHOR]