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WiFi-like Nanostructures from Confinement of Block Copolymer Microdomains in Asymmetric Hemisphere Nanocavity
No full textWe investigated the morphology of lamellae-forming polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) confined in asymmetric hemisphere nanocavities which were prepared by oblique angle deposition of gold with various thicknesses. When the thickness of the deposited gold layer (tAu) was 0.5L0 of PS-b-PMMA (L0 is the lamellar domain spacing of PS-b-PMMA in bulk), concentric lamellar patterns were formed on the top surface of the nanocavities. Interestingly, at tAu = 1L0, WiFi-like nanopatterns were observed on the top surface. This is because of the reduction of dislocations of PS and PMMA lamellar microdomains near the center of the nanocavity. The experimentally observed morphologies are consistent with prediction by self-consistent field theory. In addition, the inner wall of the hemispherical nanocavity was modified by grafting three different polymer brushes (PS, PMMA, and PS-r-PMMA) to change the affinity to each block. When the nanocavity was grafted by PMMA, WiFi-like nanopatterns were observed. On the other hand, laterally stacked U-shaped nanopatterns were formed in a nanocavity grafted by PS-r-PMMA with neutral affinity to PS and PMMA. We also fabricated an array of silver WiFi-like nanopatterns composed of laterally stacked split-ring resonators after selective silver deposition only on the PS microdomains. They showed unique plasmonic resonances depending on the polarization angle of incident light in near-infrared (NIR) wavelengths. The nanopatterns with broken symmetry obtained in this study can be used in advanced optical devices for structural coloration and optical anticounterfeiting
Tailoring Two-Dimensional Matter Using Strong Light???Matter Interactions
No full textThe shaping of matter into desired nanometric structures with on-demand functionalities can enhance the miniaturization of devices in nanotechnology. Herein, strong light???matter interaction was used as an optical lithographic tool to tailor two-dimensional (2D) matter into nanoscale architectures. We transformed 2D black phosphorus (BP) into ultrafine, well-defined, beyond-diffraction-limit nanostructures of ten times smaller size and a hundred times smaller spacing than the incident, femtosecond-pulsed light wavelength. Consequently, nanoribbons and nanocubes/cuboids scaling tens of nanometers were formed by the structured ablation along the extremely confined periodic light fields originating from modulation instability, the tailoring process of which was visualized in real time via light-coupled in situ transmission electron microscopy. The current findings on the controllable nanoscale shaping of BP will enable exotic physical phenomena and further advance the optical lithographic techniques for 2D materials
Investigation of thermoelastic compliances considering finite strain
No full textTopology optimization of thermoelastic structures is of significance in many engineering applications such as for additive manufacturing, metamaterials, and soft robotics. To ensure that a structure performs adequately over a wide range of thermoelastic loading conditions and thermal expansion, incorporating the finite strain theory in the design strategy is critical. In this study, we investigate the two energy-based objective functions, namely the end compliance and strain energy under thermomechanical conditions. The numerical examples considered indicate that the optimized layout is highly dependent on the selected objective function; such differences among the layouts can be attributed to the manner in which the structure accommodates the changing temperature. The end compliance is minimized by leveraging the direction of the thermal load to offset the mechanical load, while the minimization of the strain energy contributes to the strength of the structure by limiting the thermal contribution to the overall stress within the structure. Furthermore, we show the effects of different strain assumptions on the optimality of layouts. Thus, this study reveals the significance of adopting each thermoelastic compliance and highlights the importance of accounting for structural nonlinearity when considering the thermal effect
Robust Topology Optimization of Continuum Structures under the Hybrid Uncertainties: A Comparative Study
No full textDue to the inevitable involvement of multisource uncertainties related to the load, material property and geometry in practical engineering designs, robust topology optimization (RTO) has recently attracted increasing attention to account for these uncertain effects. However, the majority of the existing RTO works are concerned with single source uncertainty, and very few studies have considered the multisource (hybrid) uncertainties simultaneously. To this end, a comparative study on the hybrid uncertainties (HU), i.e., material-loading, geometric-loading, material-geometric, and material-geometric-loading uncertainties, for RTO of continuum structures is presented in this paper. A truncated Karhunen-Loeve expansion is adopted for uncertainty representation and a sparse grid collocation method for uncertainty propagation of the objective function and constraints. Effects of the various HU on the compliance and robust design are comprehensively investigated and compared with the RTO models under individual component uncertainty using two continuum benchmarks. An important observation from the results is that the hybrid uncertainty model is a conservative state, and the resulting RTO designs tend towards those with loading uncertainty only
Effects of NiCl2 and FeCl2 additives on the anodic dissolution behaviours of Inconel 600 in molten LiCl???KCl salts
No full textThe anodic dissolution behaviour of Inconel 600 must be elucidated to design an efficient decontamination process for used nuclear steam generator tubes with radioactive nuclide depositions in their surface microcracks. We investigated the effects of NiCl2 and FeCl2 additives in LiCl???KCl eutectic salts on the microstructural changes in Inconel 600 during electrolytic decontamination. A Cr???Fe depletion layer formed on Inconel 600 via Ni reduction at the position where alloying elements oxidised. In the FeCl2-added salt, the selective dissolution of active alloying elements through the grain boundary produced a cavity-cluster layer whose shape was changed using applied electrochemical methods
Gamma-Aminobutyric Acid Signaling in Damage Response, Metabolism, and Disease
No full textGamma-aminobutyric acid (GABA) plays a crucial role in signal transduction and can function as a neurotransmitter. Although many studies have been conducted on GABA in brain biology, the cellular function and physiological relevance of GABA in other metabolic organs remain unclear. Here, we will discuss recent advances in understanding GABA metabolism with a focus on its biosynthesis and cellular functions in other organs. The mechanisms of GABA in liver biology and disease have revealed new ways to link the biosynthesis of GABA to its cellular function. By reviewing what is known about the distinct effects of GABA and GABA-mediated metabolites in physiological pathways, we provide a framework for understanding newly identified targets regulating the damage response, with implications for ameliorating metabolic diseases. With this review, we suggest that further research is necessary to develop GABA's beneficial and toxic effects on metabolic disease progression
A data-driven adaptive algorithm and decision support design of multisensory information fusion for prognostics and health management applications
No full textMultisensory systems play a critical role in prognostics and health management (PHM), and utilise the information from multi-device synchronous measurements for fault diagnosis and predictive maintenance. But it is not suitable for specific systems with limited bandwidth and energy reservoirs since the increased sophistication of measurement devices requires more computation and power resources. This research explores a data-driven analytical framework for multisensory system analysis and design in PHM. The proposed framework provides the optimal subset of reliable sensors to make trade-offs between accuracy demands and system constraints. The integration definition for function modelling method is adopted for modelling and functional analysis of the proposed framework. An adaptive signal conversion algorithm is designed to process the data from all reliable sensors in the system. The convolutional neural network with residual learning is built for automatic feature extraction. Combined with the evaluation rules and expert knowledge, performance analyses are obtained, including qualitative results, fault diagnosis, and the optimal sensor combination. An open-source bearing dataset of the multisensory system with five measurements is conducted to demonstrate the effectiveness and feasibility of the proposed framework
GPR143 controls ESCRT-dependent exosome biogenesis and promotes cancer metastasis
No full textExosomes transport a variety of macromolecules and modulate intercellular communication in physiology and disease. However, the regulation mechanisms that determine exosome contents during exosome biogenesis remain poorly understood. Here, we find that GPR143, an atypical GPCR, controls the endosomal sorting complex required for the transport (ESCRT)-dependent exosome biogenesis pathway. GPR143 interacts with HRS (an ESCRT-0 Subunit) and promotes its association to cargo proteins, such as EGFR, which subsequently enables selective protein sorting into intraluminal vesicles (ILVs) in multivesicular bodies (MVBs). GPR143 is elevated in multiple cancers, and quantitative proteomic and RNA profiling of exosomes in human cancer cell lines showed that the GPR143-ESCRT pathway promotes secretion of exosomes that carry unique cargo, including integrins signaling proteins. Through gain- and loss-of-function studies in mice, we show that GPR143 promotes metastasis by secreting exosomes and increasing cancer cell motility/invasion through the integrin/FAK/Src pathway. These findings provide a mechanism for regulating the exosomal proteome and demonstrate its ability to promote cancer cell motility
Characteristics of tropical cyclones over the western North Pacific related to extreme ENSO and a climate regime shift in sub-seasonal forecasting with GloSea5
No full textThe characteristics of tropical cyclones (TCs) in sub-seasonal forecasting with the Global Seasonal Forecast System 5 (GloSea5) of the Korea Meteorological Administration (KMA) were assessed for June-September (JJAS) from 1991 to 2010 over the western North Pacific (WNP). The performance of GloSea5 was examined for its ability to reproduce observed TC climatology as well as changes in TC genesis with the El Nino-Southern Oscillation (ENSO) and a 1998/1999 climate regime shift (e.g., frequency, genesis spatial distribution). GloSea5 showed skillful performance in predicting the frequency and genesis spatial distribution of TCs in climatology and both ENSO phases; this performance was best during periods of La Nina. Environmental fields related to TC genesis (e.g., sea surface temperature [SST], vertical wind shear [VWS], 850-hPa wind and relative vorticity) were also reasonably captured, despite some systematic biases in SST, low-level circulation, relative vorticity, and VWS. GloSea5 performed well in terms of characteristic of changes in TC genesis before and after the regime shift. However, there were biases in TC frequency before the regime shift and changes in TC-related environmental fields. Our results imply that GloSea5 with a high predictive skill for TC genesis over the WNP can be used as an operational model for sub-seasonal TC forecasting, although it requires continuous improvements to reduce systematic errors
A product acceptance decision-making method based on process capability with considering gauge measurement errors
No full textAn acceptance sampling plan is an essential technique for quality assurance in manufacturing industries to help producers and buyers make appropriate decisions regarding many products. By providing the required sample sizes and critical value, the plan streamlines the quality standards process. The recent attention paid to acceptance sampling plans has tended to emphasize the process capability index while neglecting gauge measurement errors (GMEs), which have a direct impact on the fraction of defectives and decision-making processes to be the detriment of stakeholders. Thus, we provide the required sample size and the critical acceptance value considering GMEs. To demonstrate the impact of GMEs on the assessment of a product's lot, we present a real case study on a bilateral switch. Information on the required number of samples for the inspection and the acceptance critical value will help lead to a reliable decision