Distributed resilient filtering of large-scale systems with channel scheduling

summary:This paper addresses the distributed resilient filtering for discrete-time large-scale systems (LSSs) with energy constraints, where their information are collected by sensor networks with a same topology structure. As a typical model of information physics systems, LSSs have an inherent merit of modeling wide area power systems, automation processes and so forth. In this paper, two kinds of channels are employed to implement the information transmission in order to extend the service time of sensor nodes powered by energy-limited batteries. Specifically, the one has the merit of high reliability by sacrificing energy cost and the other reduces the energy cost but could result in packet loss. Furthermore, a communication scheduling matrix is introduced to govern the information transmission in these two kind of channels. In this scenario, a novel distributed filter is designed by fusing the compensated neighboring estimation. Then, two matrix-valued functions are derived to obtain the bounds of the covariance matrices of one-step prediction errors and the filtering errors. In what follows, the desired gain matrices are analytically designed to minimize the provided bounds with the help of the gradient-based approach and the mathematical induction. Furthermore, the effect on filtering performance from packet loss is profoundly discussed and it is claimed that the filtering performance becomes better when the probability of packet loss decreases. Finally, a simulation example on wide area power systems is exploited to check the usefulness of the designed distributed filter

Efficient refinements on YOLOv3 for real-time detection and assessment of diabetic foot Wagner grades

Currently, the screening of Wagner grades of diabetic feet (DF) still relies on professional podiatrists. However, in less-developed countries, podiatrists are scarce, which led to the majority of undiagnosed patients. In this study, we proposed the real-time detection and location method for Wagner grades of DF based on refinements on YOLOv3. We collected 2,688 data samples and implemented several methods, such as a visual coherent image mixup, label smoothing, and training scheduler revamping, based on the ablation study. The experimental results suggested that the refinements on YOLOv3 achieved an accuracy of 91.95% and the inference speed of a single picture reaches 31ms with the NVIDIA Tesla V100. To test the performance of the model on a smartphone, we deployed the refinements on YOLOv3 models on an Android 9 system smartphone. This work has the potential to lead to a paradigm shift for clinical treatment of the DF in the future, to provide an effective healthcare solution for DF tissue analysis and healing status.Comment: 11 pages with 11 figure

Exploring High Aspect Ratio Gold Nanotubes as Cytosolic Agents: Structural Engineering and Uptake into Mesothelioma Cells.

The generation of effective and safe nanoagents for biological applications requires their physicochemical characteristics to be tunable, and their cellular interactions to be well characterized. Here, the controlled synthesis is developed for preparing high-aspect ratio gold nanotubes (AuNTs) with tailorable wall thickness, microstructure, composition, and optical characteristics. The modulation of optical properties generates AuNTs with strong near infrared absorption. Surface modification enhances dispersibility of AuNTs in aqueous media and results in low cytotoxicity. The uptake and trafficking of these AuNTs by primary mesothelioma cells demonstrate their accumulation in a perinuclear distribution where they are confined initially in membrane-bound vesicles from which they ultimately escape to the cytosol. This represents the first study of the cellular interactions of high-aspect ratio 1D metal nanomaterials and will facilitate the rational design of plasmonic nanoconstructs as cytosolic nanoagents for potential diagnosis and therapeutic applications.BLF-Papworth Fellowship from the British Lung Foundation and the Victor Dahdaleh Foundation

One-step fabrication of hollow-channel gold nanoflowers with excellent catalytic performance and large single-particle SERS activity.

Hollow metallic nanostructures have shown potential in various applications including catalysis, drug delivery and phototherapy, owing to their large surface areas, reduced net density, and unique optical properties. In this study, novel hollow gold nanoflowers (HAuNFs) consisting of an open hollow channel in the center and multiple branches/tips on the outer surface are fabricated for the first time, via a facile one-step synthesis using an auto-degradable nanofiber as a bifunctional template. The one-dimensional (1D) nanofiber acts as both a threading template as well as a promoter of the anisotropic growth of the gold crystal, the combination of which leads to the formation of HAuNFs with a hollow channel and nanospikes. The synergy of favorable structural/surface features, including sharp edges, open cavity and high-index facets, provides our HAuNFs with excellent catalytic performance (activity and cycling stability) coupled with large single-particle SERS activity (including ∼30 times of activity in ethanol electro-oxidation and ∼40 times of single-particle SERS intensity, benchmarked against similar-sized solid gold nanospheres with smooth surfaces, as well as retaining 86.7% of the initial catalytic activity after 500 cycles in ethanol electro-oxidation). This innovative synthesis gives a nanostructure of the geometry distinct from the template and is extendable to fabricating other systems for example, hollow-channel silver nanoflowers (HAgNFs). It thus provides an insight into the design of hollow nanostructures via template methods, and offers a versatile synthetic strategy for diverse metal nanomaterials suited for a broad range of applications

Sub‐nanometer thick gold nanosheets: sub‐nanometer thick gold nanosheets as highly efficient catalysts (Adv. Sci. 21/2019)

In article number 1900911, Stephen D. Evans and co‐workers develop an ambient aqueous synthesis for preparing atomically‐thin gold nanosheets (termed gold nanoseaweed, AuNSW, because of its morphology, color and aqueous growth). These AuNSWs represent the first free‐standing 2D gold with a sub‐nanometer thickness (0.47 nm, e.g., two atomic layers thick), and exhibit excellent catalysis performance in the model reaction of 4‐nitrophenol reduction, as well as remarkable peroxidase‐mimicking activity

Sub‐nanometer thick gold nanosheets as highly efficient catalysts

2D metal nanomaterials offer exciting prospects in terms of their properties and functions. However, the ambient aqueous synthesis of atomically‐thin, 2D metallic nanomaterials represents a significant challenge. Herein, freestanding and atomically‐thin gold nanosheets with a thickness of only 0.47 nm (two atomic layers thick) are synthesized via a one‐step aqueous approach at 20 °C, using methyl orange as a confining agent. Owing to the high surface‐area‐to‐volume ratio, abundance of unsaturated atoms exposed on the surface and large interfacial areas arising from their ultrathin 2D nature, the as‐prepared Au nanosheets demonstrate excellent catalysis performance in the model reaction of 4‐nitrophenol reduction, and remarkable peroxidase‐mimicking activity, which enables a highly sensitive colorimetric sensing of H2O2 with a detection limit of 0.11 × 10−6 m. This work represents the first fabrication of freestanding 2D gold with a sub‐nanometer thickness, opens up an innovative pathway toward atomically‐thin metal nanomaterials that can serve as model systems for inspiring fundamental advances in materials science, and holds potential across a wide region of applications

Sub‐nanometer thick gold nanosheets: sub‐nanometer thick gold nanosheets as highly efficient catalysts (Adv. Sci. 21/2019)

In article number 1900911, Stephen D. Evans and co‐workers develop an ambient aqueous synthesis for preparing atomically‐thin gold nanosheets (termed gold nanoseaweed, AuNSW, because of its morphology, color and aqueous growth). These AuNSWs represent the first free‐standing 2D gold with a sub‐nanometer thickness (0.47 nm, e.g., two atomic layers thick), and exhibit excellent catalysis performance in the model reaction of 4‐nitrophenol reduction, as well as remarkable peroxidase‐mimicking activity

Metformin promotes osteogenic differentiation and prevents hyperglycaemia-induced osteoporosis by suppressing PPARγ expression

Metformin can prevent hyperglycaemia-induced osteoporosis and decrease the bone fracture rate, but the mechanism has not been fully elucidated. To reveal the mechanism by which metformin affects hyperglycaemia-induced osteoporosis, we treat a mouse osteoporosis cell model with metformin and find that osteoblast mineralization increases and PPARγ expression decreases. Single-cell mRNA sequencing analysis show that PPARγ is highly expressed in the bone tissue of osteoporosis patients, which highlights the role of PPARγ in osteoporosis. Furthermore, we find that PPARγ is the effector through which metformin prevents osteoporosis. We further examine the mechanism of PPARγ regulation and reveal that metformin regulates PPARγ expression through the AMPK pathway and that PPARγ affects osteoblasts through the endoplasmic reticulum stress (ERS) pathway. Moreover, we verify the association between the effect of metformin on bone metabolism and the expression of PPARγ in high-fat diet-induced diabetic rats. Thus, we identify and functionally validate that metformin prevents hyperglycaemia-induced osteoporosis by regulating the AMPK-PPARγ-ERS axis

Facile fabrication of PS/Fe3O4@PANi nanocomposite particles and their application for the effective removal of Cu2+

This work presents a simple and straightforward approach to fabricating multifunctional nanocomposite particles which possess a core of a polystyrene (PS) particle, a transition layer of magnetic Fe3O4 nanoparticles (NPs), and an outer shell of adsorbable polyaniline (PANi). In detail, the positively charged Fe3O4 NPs synthesized via the chemical co-precipitation method are directly loaded onto the negatively charged surfaces of the PS particles obtained by emulsifier-free emulsion polymerization through electrostatic self-assembly; subsequently, the coating of the resultant PS/Fe3O4 nanocomposite particles with PANi was successfully achieved by virtue of the "swelling-diffusion-interfacial-polymerization method'' (SDIPM). Furthermore, the adsorption of Cu2+ by PS/Fe3O4@ PANi nanocomposite particles was investigated by changing the initial pH value, adsorption time, and initial concentration of the adsorbate. The adsorption data in our work follow a pseudo-second-order kinetics model and fit the Langmuir isotherm model. The PS/Fe3O4@ PANi nanocomposite particles show that the maximum adsorption capacity is up to 181.5 mg g(-1) at pH 5. More importantly, these nanocomposite particles can be easily recovered using an external magnetic field owing to the presence of Fe3O4 NPs, and the regenerated nanocomposite particles can be repeatedly used for eight cycles without significant loss of their adsorption capacity