Non-local methods for DNA detection and image restoration

Many methods have been developed for abnormal linear systems. However, these methods often assume locality for datasets; thus the features of the data cannot be extracted most efficiently to formulate models, which can lead to the loss of information and incorrect results. To overcome the disadvantages of locality methods, we develop new adaptive non-local data analysis methods for two kinds of linear systems and apply the methods to two applications: component detection in multiplexed Raman spectra and image restoration. The first application, which was a project sponsored by Renishaw, involves the detection of component dyes from an observed DNA spectrum. The second application is to approximate original scenes from observed images degraded by blurring and noise. In contrast to pointwise methods, our methods investigate patches or neighbourhoods in datasets and extract features from these patches for discrimination and denoising through correlation analysis of the similarity of patches. Inthisthesis, our methods are developed by combining non-local data analysis with many popular traditional algorithms, such as model selection with the maximum p-value, conjugate gradient descent and the iteration method of higher convergence order; therefore, our methods are general and can be utilised for further applications to other image processing problems

A Wireless Covert Channel Based on Constellation Shaping Modulation

Wireless covert channel is an emerging covert communication technique which conceals the very existence of secret information in wireless signal including GSM, CDMA, and LTE. The secret message bits are always modulated into artificial noise superposed with cover signal, which is then demodulated with the shared codebook at the receiver. In this paper, we first extend the traditional KS test and regularity test in covert timing channel detection into wireless covert channel, which can be used to reveal the very existence of secret data in wireless covert channel from the aspect of multiorder statistics. In order to improve the undetectability, a wireless covert channel for OFDM-based communication system based on constellation shaping modulation is proposed, which generates additional constellation points around the standard points in normal constellations. The carrier signal is then modulated with the dirty constellation and the secret message bits are represented by the selection mode of the additional constellation points; shaping modulation is employed to keep the distribution of constellation errors unchanged. Experimental results show that the proposed wireless covert channel scheme can resist various statistical detections. The communication reliability under typical interference is also proved

Tuning the Magnetic Ordering Temperature of Hexagonal Ferrites by Structural Distortion Control

To tune the magnetic properties of hexagonal ferrites, a family of magnetoelectric multiferroic materials, by atomic-scale structural engineering, we studied the effect of structural distortion on the magnetic ordering temperature (TN). Using the symmetry analysis, we show that unlike most antiferromagnetic rare-earth transition-metal perovskites, a larger structural distortion leads to a higher TN in hexagonal ferrites and manganites, because the K3 structural distortion induces the three-dimensional magnetic ordering, which is forbidden in the undistorted structure by symmetry. We also revealed a near-linear relation between TN and the tolerance factor and a power-law relation between TN and the K3 distortion amplitude. Following the analysis, a record-high TN (185 K) among hexagonal ferrites was predicted in hexagonal ScFeO3 and experimentally verified in epitaxially stabilized films. These results add to the paradigm of spin-lattice coupling in antiferromagnetic oxides and suggests further tunability of hexagonal ferrites if more lattice distortion can be achieved

Injectable Self‐Healing Antibacterial Bioactive Polypeptide‐Based Hybrid Nanosystems for Efficiently Treating Multidrug Resistant Infection, Skin‐Tumor Therapy, and Enhancing Wound Healing

The surgical procedure in skin‐tumor therapy usually results in cutaneous defects, and multidrug‐resistant bacterial infection could cause chronic wounds. Here, for the first time, an injectable self‐healing antibacterial bioactive polypeptide‐based hybrid nanosystem is developed for treating multidrug resistant infection, skin‐tumor therapy, and wound healing. The multifunctional hydrogel is successfully prepared through incorporating monodispersed polydopamine functionalized bioactive glass nanoparticles (BGN@PDA) into an antibacterial F127‐ε‐Poly‐L‐lysine hydrogel. The nanocomposites hydrogel displays excellent self‐healing and injectable ability, as well as robust antibacterial activity, especially against multidrug‐resistant bacteria in vitro and in vivo. The nanocomposites hydrogel also demonstrates outstanding photothermal performance with (near‐infrared laser irradiation) NIR irradiation, which could effectively kill the tumor cell (>90%) and inhibit tumor growth (inhibition rate up to 94%) in a subcutaneous skin‐tumor model. In addition, the nanocomposites hydrogel effectively accelerates wound healing in vivo. These results suggest that the BGN‐based nanocomposite hydrogel is a promising candidate for skin‐tumor therapy, wound healing, and anti‐infection. This work may offer a facile strategy to prepare multifunctional bioactive hydrogels for simultaneous tumor therapy, tissue regeneration, and anti‐infection.This paper reports an intrinsically multifunctional bioactive hybrid hydrogel for treating multidrug resistant infection, skin‐tumor therapy, and wound healing. The hybrid hydrogels display excellent self‐healing and injectable ability, as well as robust antibacterial activity, especially against multidrug‐resistant bacteria in vitro and in vivo, and also efficiently inhibits tumor growth and enhances wound healing.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149555/1/adfm201806883.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149555/2/adfm201806883-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149555/3/adfm201806883_am.pd

Enhanced superconductivity in TiO epitaxial thin films

Titanium oxides have many fascinating optical and electrical properties, such as the superconductivity at 2 K in cubic titanium monoxide (TiO) polycrystalline bulk. However, the lack of TiO single crystals or epitaxial films has prevented systematic investigations on its superconductivity. Here, we report the basic superconductivity characterizations of cubic TiO films epitaxially grown on (0001)-oriented α-Al2O3 substrates. The magnetic and electronic transport measurements confirmed that TiO is a type-II superconductor and the recorded high Tc is about 7.4 K. The lower critical field (Hc1) at 1.9 K, the extrapolated upper critical field Hc2(0), and coherence length are about 18 Oe, 13.7 T, and 4.9 nm, respectively. With increasing pressure, the value of Tc shifts to lower temperature while the normal state resistivity increases. Our results on the superconducting TiO films confirm the strategy to achieve higher Tc in the epitaxial films, which may be helpful for finding more superconducting materials in various related systems