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Intradialytic hypotension (IDH) is a common complication of hemodialysis (HD), but there is no consensus on its definition. In 2015, Flythe proposed a definition of IDH (Definition 1 in this study): nadir systolic blood pressure (SBP) <90 mmHg during hemodialysis for patients with pre-dialysis SBP <159 mmHg, and nadir SBP <100 mmHg during hemodialysis for patients with pre-dialysis SBP ≥160 mmHg. This prospective observational cohort study investigated the association of frequent IDH based on Definition 1 with clinical outcomes and compared Definition 1 with a commonly used definition (nadir SBP <90 mmHg during hemodialysis, Definition 2). The incidence of IDH was observed over a 3-month exposure assessment period. Patients with IDH events ≥30% were classified as 'frequent IDH'; the others were 'infrequent IDH'. All-cause mortality, cardiovascular mortality, and all-cause hospitalization events were followed up for 36 months. This study enrolled 163 HD patients. The incidence of IDH was 11.1% according to Definition 1 and 10.5% according to Definition 2. The Kaplan-Meier curves showed that frequent IDH patients had higher risks of all-cause mortality (p = 0.009, Definition 1; p = 0.002, Definition 2) and cardiovascular mortality (p = 0.021, Definition 1). Multivariable Cox regression analysis indicated that frequent IDH was independently associated with a higher risk of all-cause mortality (Model 1: HR = 2.553, 95%CI 1.334–4.886, p = 0.005; Model 2: HR = 2.406, 95%CI 1.253–4.621, p = 0.008). In conclusion, HD patients classified as frequent IDH are at a greater risk of all-cause mortality. This highlights the significance of acknowledging and proactively managing frequent IDH within the HD patients. [ABSTRACT FROM AUTHOR]

Identifying template watermarks under severe geometric distortions is a significant scientific problem in the current watermarking research for remote sensing images. We propose a novel watermarking algorithm that integrates the ring-shaped template watermark with the multiscale local contrast measure (LCM) method. In the embedding stage, the ring-shaped template watermark is embedded into the discrete Fourier transform (DFT) magnitude coefficients, converting the watermark into small targets in the DFT domain. During the detection stage, the multiscale LCM, a classic infrared small target detection method, enhances these small targets and generates a contrast map. Peak detection is then performed on the contrast map to determine the radius of the template watermark. Finally, circular edge local binarization is applied to extract the watermark information. The proposed method enables synchronization recovery of watermarks under blind conditions. The experimental results demonstrate that the method possesses strong robustness against various geometric attacks such as rotation, scaling, translation, and cropping. It outperforms comparative algorithms in terms of robustness and also exhibits good imperceptibility. [ABSTRACT FROM AUTHOR]

The surrounding rock of coal mining face often contains numerous micro-cracks, and these microcracks greatly restrict the mechanical strength of the rock. Mechanical properties of rock degraded by joints and fissures in rock,, taking the Mesozoic three-stream pluton granite in Dandong City, Liaodong uplift area as an example,, establish a particle flow model and use the "trial and error method" to repeatedly calibrate the microscopic parameters until they are consistent with the actual situation,, uniaxial compression tests were performed on rock masses with different fissures, and 16 orthogonal discrete element numerical simulation experiments with 4 factors and 4 levels were carried out. Based on multiple linear regression analysis, the influence of four factors on the mechanical properties of granite was analysed, and the influence of single factor on the macro-mechanical properties of granite was studied through numerical experiments. The results show that the effect of the crack geometry on the peak strength of granite is greater than the effect on the elastic modulus of granite; The order of the influence degree of the crack geometric characteristic parameters on the peak strength is the crack Y-axis position component > the crack X-axis position component > the crack length > the crack inclination angle; The order of the influence degree of the crack geometric characteristic parameters on the elastic modulus is the crack X-axis position component > the crack Y-axis position component > the crack length > the crack inclination angle; The crack initiation position gradually moves to both ends of the crack as the angle increases. The specimen is mainly dominated by tension cracks, and the crack tip is accompanied by local shear failure; The longer the crack length, the lower the peak strength of the granite, and the worse the stability; The positional change of primary microcracks in granite mainly changes the peak strength and post-peak stress-strain state of the rock sample, but has no significant effect on the elastic modulus. The research results have certain reference value for predicting the mechanical properties of fractured granite.

Textural morphology is an important factor influencing dry friction, and few studies have been conducted regarding the effects of single- and multi-shape textures on dry tribological properties. In this work, six types of textures including single- and multi-shape textures were produced on 40Cr steel samples by using a nanosecond laser. Reciprocating sliding tests under dry friction were conducted using a pin-on-disc friction tester. The influences of textured surfaces with different textures on tribological properties were investigated. Results showed that tribological properties were affected by different textural morphologies. The dimple-textured surface had the highest friction coefficient, followed by the groove-textured surface. The sinusoidal-textured surface had the lowest friction coefficient. The friction coefficients of multi-shape textured surfaces were lower than those of non-textured surfaces but higher than those of sinusoidal-textured surfaces. The wear properties of the tested surfaces were consistent with the friction-coefficient results. The sinusoidal- and sinusoidal–groove-textured surfaces can be considered as the optimum choices for dry reciprocating friction. [ABSTRACT FROM AUTHOR]