•We propose an improved cross coupled map lattice model.•We design a bit-level image encryption scheme using the proposed model.•Bit-level confusion and diffusion are related to our model and ...plain-image.•The proposed method in this paper can resist the common attacks.
In this paper, an improved cross coupled map lattice (CCML) which is derived from CCML is proposed. The experimental analysis of CCML shows that it exhibits weak or even lose chaotic behaviors in a large range of parameters. To enhance its chaotic performance, the new model changes the internal chaotic map of CCML from the logistics map to the tent map and introduces the module operations to limit the obtained value. The theoretical analysis and experimental results prove that the proposed model has a broad chaotic regime over an extensive range of system parameters, positive Lyapunov exponents, higher information entropies and lower mutual information values when compared to CCML, which are highly suitable for chaos-based image encryption. Moreover, this paper applies that model on a bit-level image encryption scheme. The algorithm consists of three main operations: the generation of secret keys, confusion and diffusion operations that can break the limitation of row and column. To confirm the novel algorithm's effectiveness and safety against the common types of attacks, many experiments are done and security analyses are discussed. It demonstrates the good chaos of the proposed model from the aspect of encryption performance.
The continuous orthogonal moments of images have become a main tool used in zero-watermarking algorithms in recent years. However, there is a problem that should not be neglected for existing ...zero-watermarking algorithms, which is known as numerical instability. Because the continuous orthogonal moments used in existing zero-watermarking algorithms are integer-order moments, this problem affects the computational accuracy of such moments and thus affects the performance of zero-watermarking algorithms. Therefore, in this paper, the integer-order radial harmonic Fourier moments (IoRHFMs) are firstly extended to fractional-order radial harmonic Fourier moments (FoRHFMs) to effectively mitigate the problem of numerical instability and improve the computational accuracy of IoRHFMs, and then a FoRHFM-based zero-watermarking algorithm for medical images is proposed to achieve lossless copyright protection of medical images. The experimental results show that this algorithm is highly robust to geometric attacks and common attacks, and is superior to IoRHFM-based and other zero-watermarking algorithms.
Different from the traditional watermarking schemes, zero-watermarking schemes are lossless embedding methods, which are applicable to be used in medical, military, remote sensing and other fields ...requiring high-integrity image copyright protection. However, most of the existing zero-watermarking schemes only provide copyright protection for one image at a time, which has certain limitations. This paper proposes a novel zero-watermarking scheme for protecting the copyright of two similar medical images simultaneously. Firstly, an accurate polar complex exponential transform (APCET) is designed using Gaussian numerical integration (GNI) method, which effectively improves the computation accuracy of polar complex exponential transform (PCET). Then, ternary accurate polar complex exponential transform (TAPCET) is constructed based on ternary number theory and APCET, which describes two similar medical images simultaneously. Finally, a robust zero-watermarking algorithm for two similar medical images is proposed based on TAPCET and chaotic mapping. The experimental results show that the proposed scheme can resist common image processing attacks and geometric attacks, and is superior to other zero-watermarking algorithms, being applicable for the copyright protection of two similar medical images simultaneously.
The traditional embedded watermarking scheme achieves copyright protection of images by embedding watermarks into the original images. This process will deteriorate the original image, so it is not ...suitable for medical images. In order to overcome this limitation, this paper proposes a geometrically invariant color medical image null-watermarking scheme based on quaternion polar harmonic Fourier moments (QPHFM), which achieves the copyright protection without changing the original medical image. First, a high-precision QPHFM computation method based on wavelet numerical integration is designed, which can effectively improve the computation precision. Then based on the precise QPHFM (PQPHFM) and chaotic map, a robust null-watermarking scheme for color medical images is proposed to protect the copyright of color medical images. This scheme uses the PQPHFM to construct feature images and its good stability and geometric invariance make the proposed null-watermarking scheme has good robustness and resistance against geometric attacks. Extensive simulation experiments show that the proposed scheme is highly robust in resisting common attacks and geometric attacks such as scaling, rotation, change of length-width ratio, and flipping. The performance of the proposed scheme is superior to that of similar robust null-watermarking schemes and other color medical image watermarking schemes.
This paper proposes aconvolutional neural network (CNN)-based efficient medical image super-resolution (SR) method in the shearlet domain. Because of differences between imaging mechanisms optimized ...for natural images and medical images, the design begins with building a medical image dataset for medical image SR and extracting effective areas to remarkably enhance the training effects of the CNN-based method. Then, a new medical image SR network structure—deep medical super-resolution network (DMSRN)—has been designed in which local residual learning is implemented through a recursive network and combined with global residual learning to heighten the depth of the network on the ground with no parameter increase. This effectively fixes the long-term dependency problem, which causes the prior state layers to barely have any effect on the following state layers. Last, the design addresses the problem of too-smooth reconstruction effects in the CNN-based method in the image space domain; shearlet transform is introduced to DMSRN to restore global topology through low-frequency sub-bands and restore local edge detail information through high-frequency sub-bands. Experimental results show that the proposed method is better than other state-of-the-art methods for medical image SR, which significantly promotes the restoration ability of texture structure and edge details.
In this paper, the problem of synchronization for a class of fully complex-valued networks with coupling delay is investigated by the linear feedback control in a finite time. The state variables, ...system function, inner coupling matrix, and outer coupling matrix in this model are set as complex values. By decomposing the complex-valued network into real and imaginary parts, an equivalent real-valued system is established. Based on the finite-time stability theory and Lyapunov functional method, linear feedback controllers are constructed to guarantee the synchronization for the complex-valued networks with or without coupling delay in a desired finite time. Then, some sufficient conditions for assurance of finite-time synchronization are given by strict proof. Finally, simulation examples are provided to verify our results.
An exaggerated exercise pressor reflex (EPR) is associated with excessive sympatho-excitation and exercise intolerance in the chronic heart failure (CHF) state. We hypothesized that brain-derived ...neurotrophic factor (BDNF) causes the exaggerated EPR via sensitizing muscle mechanosensitive afferents in CHF. Increased BDNF expression was observed in lumbar dorsal root ganglia (DRGs) from CHF rats compared to sham rats. Immunofluorescence data showed a greater increase in the number of BDNF-positive neurons in medium and large-sized DRG subpopulations from CHF rats. Patch clamp data showed that incubation with BDNF for 4⁻6 h, significantly decreased the current threshold-inducing action potential (AP), threshold potential and the number of APs during current injection in Dil-labeled isolectin B4 (IB4)-negative medium-sized DRG neurons (mainly mechano-sensitive) from sham rats. Compared to sham rats, CHF rats exhibited an increased number of APs during current injection in the same DRG subpopulation, which was significantly attenuated by 4-h incubation with anti-BDNF. Finally, chronic epidural delivery of anti-BDNF attenuated the exaggerated pressor response to either static contraction or passive stretch in CHF rats whereas this intervention had no effect on the pressor response to hindlimb arterial injection of capsaicin. These data suggest that increased BDNF in lumbar DRGs contributes to the exaggerated EPR in CHF.
•A robust stereo image zero-watermarking algorithm based on TRHFM is proposed.•Ternary number theory is used in stereo image processing for the first time.•TRHFM is applied to stereo image ...zero-watermarking algorithm for the first time.•The proposed algorithm is robust to asymmetric and symmetric attacks.•Logistic mapping leads to excellent security.
With the development and popularization of computer network technology, the copyright protection of stereo images is a serious problem to be solved. Based on ternary number theory and radial harmonic Fourier moments (RHFM), ternary radial harmonic Fourier moments (TRHFM) is proposed to deal with stereo images in a holistic manner, and based on this moment, this paper proposes a robust stereo image zero-watermarking algorithm. We first compute the TRHFM of the original stereo image, and we randomly select TRHFMs using logistic mapping; then, we obtain a binary feature image using the magnitudes of the selected TRHFMs, and finally, we apply a bitwise exclusive-or operation on permuted logo image and binary feature image to obtain the zero-watermark image. Experimental results indicate that the proposed stereo image zero-watermarking algorithm is strongly robust to various asymmetric and symmetric attacks and has superiority compared with other zero-watermarking algorithms.
The cardio-renal syndrome (CRS) type 2 is defined as a progressive loss of renal function following a primary insult to the myocardium that may be either acute or chronic but is accompanied by a ...decline in myocardial pump performance. The treatment of patients with CRS is difficult, and the disease often progresses to end-stage renal disease that is refractory to conventional therapy. While a good deal of information is known concerning renal injury in the CRS, less is understood about how reflex control of renal sympathetic nerve activity affects this syndrome. In this review, we provide insight into the role of the renal nerves, both from the afferent or sensory side and from the efferent side, in mediating renal dysfunction in CRS. We discuss how interventions such as renal denervation and abrogation of systemic reflexes may be used to alleviate renal dysfunction in the setting of chronic heart failure. We specifically focus on a novel cardiac sensory reflex that is sensitized in heart failure and activates the sympathetic nervous system, especially outflow to the kidney. This so-called Cardiac Sympathetic Afferent Reflex (CSAR) can be ablated using the potent neurotoxin resinferitoxin due to the high expression of Transient Receptor Potential Vanilloid 1 (TRPV1) receptors. Following ablation of the CSAR, several markers of renal dysfunction are reversed in the post-myocardial infarction heart failure state. This review puts forth the novel idea of neuromodulation at the cardiac level in the treatment of CRS Type 2.
A systematic analysis of clinical trials was performed in order to assess the effectiveness and risks of bilateral renal denervation (RDN) in patients with chronic heart failure with reduced ejection ...fraction (HFrEF).
A systematic review was conducted of all clinical trials exploring the effectiveness of RDN in patients with HF who had reduced (<50%) EF. Primary outcomes were NYHA class, 6-min walk test, N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, left ventricular ejection fraction (LVEF) and other cardiac parameters including left ventricular end-systolic diameter (LVESD), left ventricular end-diastolic diameter (LVEDD), and left atrium diameter (LAD). Secondary outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), glomerular filtration rate (GFR), and creatinine.
Seven studies were included in this analysis. From baseline to 6 months after RDN, the pooled mean NYHA class was decreased (mean difference MD, -0.9; 95% confidence interval CI, -1.6 to -0.2; P = 0.018), the mean 6-min walk test was increased (MD, 79.5 m; 95% CI, 26.9 to 132.1; P = 0.003), and the average NT-proBNP level was decreased (MD, -520.6 pg/mL; 95% CI, -1128.4 to 87.2; P = 0.093). Bilateral RDN increased the LVEF (MD, 5.7%; 95% CI, 1.6 to 9.6; P = 0.004), decreased the LVESD (MD, -0.4 cm; 95% CI, -0.5 to -0.2; P < 0.001), decreased the LVEDD (MD, -0.5 cm; 95% CI, -0.6 to -0.3; P < 0.001), and decreased the LAD (MD, -0.4 cm; 95% CI, -0.8 to 0; P = 0.045). In addition, RDN significantly decreased systolic BP (MD, -9.4 mmHg; 95% CI, -16.3 to -2.4; P = 0.008) and diastolic BP (MD, -4.9 mmHg; 95% CI, -9.5 to -0.4; P = 0.033), and decreased HR (MD, -4.5 bpm; 95% CI, -8.2to -0.9; P = 0.015). RDN did not significantly change GFR (MD, 7.9; 95% CI, -5.0 to 20.8; P = 0.230), or serum creatinine levels (MD, -7.2; 95% CI, -23.7 to 9.4; P = 0.397).
Bilateral RDN appears safe and well-tolerated in patients with HF. RDN improved the signs and symptoms of HF and slightly decreased systolic and diastolic BP without affecting renal function in the clinical trials performed to date.
Chronic heart failure, Renal denervation, Sympatho-excitation.
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