Nanoscale element behavior in a continuum

Patterns in materials are not just decoration but also important for function. In view of this, the dynamics of patterning procedures in materials has been investigated as an important developmental procedure. In this study, nanoscale components in a continuum are traced in terms of natural patterning procedures. Externally applied compressive or extensive forces to an elastic thin sheet commonly induce an orientated lateral line pattern. From a nanoscale element point of view, the dynamics of natural arrangements, forming anisotropic patterns in preference to isotropy, still remains unclear. In this study, new developmental procedures for line patterns are suggested by stimuli-responsive viscoelastic nanocomposite network model systems. Forces originating from an internal source without directional orientation generate lines in preference to isotropic patterns. With repeated, non-oriented (or isotropic) and self-modulated strain variations, stress is accumulated to drive anisotropic orientations and further lines. The anisotropic elemental arrangement is justified by the equilibrium between the short-range attraction and long-range repulsion from a bottom-up viewpoint. This study suggests a new material design methodology that is useful for electrical devices, biomedical devices and other patterned soft condensed matter in conjunction with line patterns typically generated in a broad range of viscoelastic materials.11Nsciescopu

Gold Nanoparticle Contrast Agents in Advanced X-ray Imaging Technologies

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All-Solid-State Lithium Battery Working without an Additional Separator in a Polymeric Electrolyte

Considering the safety issues of Li ion batteries, an all-solid-state polymer electrolyte has been one of the promising solutions. Achieving a Li ion conductivity of a solid-state electrolyte comparable to that of a liquid electrolyte (>1 mS/cm) is particularly challenging. Even with characteristic ion conductivity, employment of a polyethylene oxide (PEO) solid electrolyte has not been sufficient due to high crystallinity. In this study, hybrid solid electrolyte (HSE) systems have been designed with Li1.3Al0.3Ti0.7(PO4)3 (LATP), PEO and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). A hybrid solid cathode (HSC) is also designed using LATP, PEO and lithium cobalt oxide (LiCoO2, LCO)—lithium manganese oxide (LiMn2O4, LMO). The designed HSE system has 2.0 × 10−4 S/cm (23 °C) and 1.6 × 10−3 S/cm (55 °C) with a 6.0 V electrochemical stability without an additional separator membrane introduction. In these systems, succinonitrile (SN) has been incorporated as a plasticizer to reduce crystallinity of PEO for practical all-solid Li battery system development. The designed HSC/HSE/Li metal cell in this study operates without any leakage and short-circuits even under the broken cell condition. The designed HSC/HSE/Li metal cell in this study displays an initial charge capacity of 82/62 mAh/g (23 °C) and 123.4/102.7 mAh/g (55 °C). The developed system overcomes typical disadvantages of internal resistance induced by Ti ion reduction. This study contributes to a new technology development of all-solid-state Li battery for commercial product design

Use of gold nanoparticles to detect water uptake in vascular plants.

Direct visualization of water-conducting pathways and sap flows in xylem vessels is important for understanding the physiology of vascular plants and their sap ascent. Gold nanoparticles (AuNPs) combined with synchrotron X-ray imaging technique is a new promising tool for investigating plant hydraulics in opaque xylem vessels of vascular plants. However, in practical applications of AuNPs for real-time quantitative visualization of sap flows, their interaction with a vascular network needs to be verified in advance. In this study, the effect of AuNPs on the water-refilling function of xylem vessels is experimentally investigated with three monocot species. Discrepancy in the water uptakes starts to appear at about 20 min to 40 min after the supply of AuNP solution to the test plant by the possible gradual accumulation of AuNPs on the internal structures of vasculature. However conclusively, it is observed that the water-refilling speeds in individual xylem vessels are virtually unaffected by hydrophilically surface-modified AuNPs (diameter ∼20 nm). Therefore, the AuNPs can be effectively used as flow tracers in the xylem vessels in the first 20∼30 min without any physiological barrier. As a result, AuNPs are found to be useful for visualizing various fluid dynamic phenomena occurring in vascular plants

Detection of circulating tumor cells via an X-ray imaging technique

Detailed information on the location and the size of tumor cells circulating through lymphatic and blood vessels is useful to cancer diagnosis. Metastasis of cancers to other non-adjacent organs is reported to cause 90% of deaths not from the primary tumors. Therefore, effective detection of circulating tumors cells (CTCs) related to metastasis is emphasized in cancer treatments. With the use of synchrotron X-ray micro-imaging techniques, high-resolution images of individual flowing tumor cells were obtained. Positively charged gold nanoparticles (AuNPs) which were inappropriate for incorporation into human red blood cells were selectively incorporated into tumor cells to enhance the image contrast. This approach enables images of individual cancer cells and temporal movements of CTCs to be captured by the high X-ray absorption efficiency of selectively incorporated AuNPs. This new technology for in vivo imaging of CTCs would contribute to improve cancer diagnosis and cancer therapy prognosis.open1156sciescopu

Comparison of water uptake volume for AuNP solution and distilled water.

<p>(A) Comparison of water uptake volume for a rice leaf. (B) Water uptake volume normalized by the exposed length of bamboo leaves (<i>n</i> = 3 for each). Variation in average water volume with the maximum and minimum value presented.</p

Experimental setup for synchrotron X-ray imaging and sample treatment.

<p>(A) Setup for visualizing the water-refilling process in 6D X-ray micro-imaging beamline of PAL. (B) Schematic description of alternative supplies of AuNPs solution and distilled water to the test sample. Each arrow between adjacent rehydration processes indicates 5 min dehydration in air.</p

Polymeric self-assembly changes by surface-modified and in-situ-grown nanoparticles

The morphology of polymeric self-assembled structures can be changed by environmental conditions, including pH, temperature, and various additives such as ions, cosolvents, nanoparticles (NPs), and so on. Studies have focused on the size and shape of NPs to investigate the effect of NP incorporation into polymeric structures. In this study, qualitative NP effect is experimentally investigated in terms of the compatibility of NPs with the self-assembled templates. Hydrophobically/hydrophilically surface-modified gold nanoparticles (AuNP) of 20 nm diameter systematically modify the surfactant number (N-s) of the self-assembled organic templates accordingly, where the driving force is determined by the hydrophilic-lipophilic force balance. AuNPs grown in situ at equlibrium in the template, decrease the N-s, reflecting selective growth of NPs in one of the self-assembly domains. Fractal density (alpha) and correlation length (zeta) of the self-assembled structures are prominently increased by any type of AuNP incorporation. (C) 2012 Elsevier Ltd. All rights reserved.X1134sciescopu

Neutron imaging of ionic solution uptake with different K⁺/Ca²⁺ ratios in plant stems.

<p><b>A</b>) Neutron images of ionic solution uptake with K⁺/Ca²⁺ ratios of 0.01, 1, and 100 in the excised laurel stems at 0, 15, 30, and 60 h after dipping in the ionic D₂O solution. Ionic D₂O uptake in the excised laurel stems was directly observed using neutron radiography. Each figure provides qualitative information on water ascent at different ionic ratios (K⁺/Ca²⁺  = 0.01 (left), K⁺/Ca²⁺  = 1 (middle), and K⁺/Ca²⁺  = 100 (right)) at 0, 15, 30, and 60 h, respectively. The average diameter of stem segments was approximately 5 mm. Scale bar represents 5 mm. <b>B</b>) Temporal variations in ionic D₂O thickness in the laurel stems for 23 h. Orange circles denote K⁺/Ca²⁺  = 0.01; green rotated triangles denote K⁺/Ca²⁺  = 1; purple rectangles denote K⁺/Ca²⁺  = 100.</p

Synchrotron X-ray micro-imaging of the ascent of water containing K⁺ and Ca²⁺ in xylem vessels.

<p><b>A</b>) Typical X-ray images showing temporal changes in the spatial distribution of ionic solution uptake mediated by varying K⁺/Ca²⁺ ratios from 0.01, 1, to 100 in the excised olive stems. Synchrotron X-ray imaging was employed to observe ionic water uptake directly through the xylem conduits of olive stems with high temporal and spatial resolution. Excised stems with a height of 15 cm took up ionic solutions with different K⁺/Ca²⁺ ratios under the same total ion concentration. Intensity-based colored figures in each column show qualitative information regarding water ascent at different ionic ratios: K⁺/Ca²⁺  =  0.01 (1^st), 1 (2^nd), and 100 (3^rd), respectively. Light blue color represents the ascent of multi-ionic solutions mixed with iopamidol as a contrast agent. The X-ray image of each column was captured at 3, 21, and 45 min, respectively. Scale bar represents 500 µm. Temporal variations in the normalized X-ray absorption intensities in the region of interest for <b>B</b>) olive stems and <b>C</b>) laurel stems. Orange circles denote K⁺/Ca²⁺  = 0.01; green rotated triangles denote K⁺/Ca²⁺  = 1; purple rectangles denote K⁺/Ca²⁺  = 100. The normalized intensity values directly represent ionic solution uptake. These figures were derived from three repeated experiments (n = 3) and error bars indicate standard deviations.</p