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Elastography is of great interest in biomechanics and medical imaging due to its nondestructive capability of mapping elasticity of tissues. The elastography framework relies on external excitations which actuate deformation inside an object. The internal response is then acquired and analyzed to map the distribution of elastic moduli. In this paper, with no need of measuring any internal responses, an integrated elastography method is developed which only requires the transmitted responses of applied sound waves. During the process, the tomography image (e.g., CT or MRI) and the applied waves are integrated into a computational model. Following a procedure of inverse analysis, the elasticity of all phases in the object is reconstructed when the computational transmission of waves matches with the measured transmission. The numerical simulation on brain tissues and a demonstration on silicon rubber phantom are conducted to validate the proposed method. Both cases demonstrate that the integrated method successfully predicts the real elasticity of samples. The verification measurements on the phantom further show that the predicted elastic moduli agree well with the experimental results of uniaxial compression testing.

Regarding the load-bearing performance of high-speed circular pad thrust bearings used in the shaft system of vertical dry gas sealed helium compressors,a lubrication performance calculation model and a stirring power consumption calculation formula for disc spring supported thrust bearings were established.Based on the model, the performance variation of circular pad thrust bearings with rotational speed and load were analyzed,and the influence of elevation error on bearing lubrication performance and support disc spring performance were also analyzed. The results show that the ratio of stirring power consumption to friction power consumption in bearings increases and decreases with the increase of speed and load, respectively. At the highest speed, stirring power consumption is more than twice that of friction power consumption. The elastic adaptive adjustment technology can effectively improve the impact of elevation error on the flatness of bearing pads.However,the larger the elevation error, the greater the difference in lubrication performance of each pad and the accumulated deformation energy of the disc springs.Therefore, for high-speed vertical rotor systems,the design of thrust bearings must consider the impact of stirring power consumption on bearing temperature rise, and further research is needed on the impact of elevation error on the stability of high-speed rotor systems. [ABSTRACT FROM AUTHOR]

Multi-drug combinations to treat bacterial populations are at the forefront of approaches for infection control and prevention of antibiotic resistance. Although the evolution of antibiotic resistance has been theoretically studied with mathematical population dynamics models, extensions to spatial dynamics remain rare in the literature, including in particular spatial evolution of multi-drug resistance. In this study, we propose a reaction-diffusion system that describes the multi-drug evolution of bacteria based on a drug-concentration rescaling approach. We show how the resistance to drugs in space, and the consequent adaptation of growth rate, is governed by a Price equation with diffusion, integrating features of drug interactions and collateral resistances or sensitivities to the drugs. We study spatial versions of the model where the distribution of drugs is homogeneous across space, and where the drugs vary environmentally in a piecewise-constant, linear and nonlinear manner. Although in many evolution models, per capita growth rate is a natural surrogate for fitness, in spatially-extended, potentially heterogeneous habitats, fitness is an emergent property that potentially reflects additional complexities, from boundary conditions to the specific spatial variation of growth rates. Applying concepts from perturbation theory and reaction-diffusion equations, we propose an analytical metric for characterization of average mutant fitness in the spatial system based on the principal eigenvalue of our linear problem, λ1. This enables an accurate translation from drug spatial gradients and mutant antibiotic susceptibility traits to the relative advantage of each mutant across the environment. Our approach allows one to predict the precise outcomes of selection among mutants over space, ultimately from comparing their λ1 values, which encode a critical interplay between growth functions, movement traits, habitat size and boundary conditions. Such mathematical understanding opens new avenues for multi-drug therapeutic optimization. Author summary: In this study we develop a framework to model multi-drug resistance evolution in space by combining drug-rescaling arguments with a reaction-diffusion type model. In response to multi-drug environmental gradients, each independent mutant can grow and diffuse following an individual spatially-varying growth function and diffusion rate. Applying concepts from perturbation theory and reaction-diffusion models, we propose an analytical metric to quantify average mutant fitness in the spatial system and to predict the outcome of selection. Our findings highlight that in spatially-extended habitats fitness is an emergent property that potentially integrates many complexities, from boundary conditions to environmental variation, as well as individual growth and diffusion traits. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the predictive value of PD-1 expression in T lymphocytes for rehospitalization due to acute exacerbations of COPD (AECOPD) in discharged patients. Methods: 115 participants hospitalized with COPD (average age 71.8 ± 6.0 years) were recruited at Fujian Provincial Hospital. PD1+T lymphocytes proportions (PD1+T%), baseline demographics and clinical data were recorded at hospital discharge. AECOPD re-admission were collected at 1-year follow-up. Kaplan-Meier analysis compared the time to AECOPD readmissions among groups stratified by PD1+T%. Multivariable Cox proportional hazards regression and stratified analysis determined the correlation between PD1+T%, potential confounders, and AECOPD re-admission. ROC and DCA evaluated PD1+T% in enhancing the clinical predictive values of Cox models, BODE and CODEX. Results: 68 participants (59.1%) were AECOPD readmitted, those with AECOPD readmission exhibited significantly elevated baseline PD-1+CD4+T/CD4+T% and PD-1+CD8 + T/CD8 + T% compared to non-readmitted counterparts. PD1+ T lymphocyte levels statistically correlated with BODE and CODEX indices. Kaplan-Meier analysis demonstrated that those in Higher PD1+ T lymphocyte proportions had reduced time to AECOPD readmission (logRank p < 0.05). Cox analysis identified high PD1+CD4+T and PD1+CD8+T ratios as risk factors of AECOPD readmission, with hazard ratios of 1.384(95%CI [1.043–1.725]) and 1.401(95%CI [1.013–1.789]), respectively. Notably, in patients aged < 70 years and with fewer than twice AECOPD episodes in the previous year, high PD1+T lymphocyte counts significantly increased risk for AECOPD readmission(p < 0.05). The AECOPD readmission predictive model, incorporating PD1+T% exhibited superior discrimination to the Cox model, BODE index and CODEX index, AUC of ROC were 0.763(95%CI [0.633–0.893]) and 0.734(95%CI [0.570–0.899]) (DeLong's test p < 0.05).The DCA illustrates that integrating PD1+T% into models significantly enhances the utility in aiding clinical decision-making. Conclusion: Evaluation of PD1+ lymphocyte proportions offer a novel perspective for identifying high-risk COPD patients, potentially providing insights for COPD management. Trial registration: Chinese Clinical Trial Registry (ChiCTR, URL: www.chictr.org.cn/), Registration number: ChiCTR2200055611 Date of Registration: 2022-01-14. [ABSTRACT FROM AUTHOR]

In the context of strong electromagnetic interference environments, the measurement accuracy of the capacitance parameters of transmission lines under power frequency measurement methods is not high. In this paper, a capacitance parameter anti-interference measurement method for transmission lines based on harmonic components is proposed to overcome the impact of power frequency interference. When applying this method, it is first necessary to open-circuit the end of the line under test. Subsequently, apply voltage to the head end of the tested line through a step-up transformer. Due to the saturation of the transformer during no-load conditions, a large number of harmonics are generated, primarily third harmonic. The third harmonic components of voltage and current on the tested transmission line are extracted using the Fourier transform. The proposed method addresses the influence of line distribution effects by establishing a distributed parameter model for long-distance transmission lines. The relevant transmission matrix for the zero-sequence distributed parameters is obtained by combining Laplace transform and similarity transform to solve the transmission line equations. Using synchronous measurement data from the third harmonic components of voltage and current at both ends of the transmission line, combined with the transmission matrix, this method accurately measures the zero-sequence capacitance parameters. The PSCAD/EMTDC simulation results and field test outcomes have demonstrated the feasibility and accuracy of the proposed method for measuring line capacitance parameters under strong electromagnetic interference. [ABSTRACT FROM AUTHOR]

A new type of UHPC‐NC (normal concrete) structure in the negative moment zone was proposed to improve the bearing capacity of the connection structure in the negative moment zone of prefabricated prestressed concrete (PC) beam bridges. First, the distribution characteristics of the crack, cracking load, ultimate moment, and ductility coefficient of the new structure were obtained by the 1:4 scale model tests. The feasibility of the connection structure is verified. Then, the value ranges of critical structural parameters affecting the bearing capacity of the connection structure based on the plane section assumption analysis, including the reasonable thickness of the UHPC layer, the reinforcement ratio of the longitudinal tensile reinforcement, and the diameter of the reinforcement, are obtained. At the same time, based on the verification of the finite element model, the influence of crucial research parameters on the bending capacity of the connection structure is obtained by using the finite element method. Finally, a theoretical method for the bending moment capacity of the connection structure of the UHPC‐NC structure is proposed, considering the high ductility characteristics of UHPC materials. The average relative error between the calculation results and the finite element method is within 7.2%, which verifies the reliability of the calculation method in this paper and provides a reference for its design and engineering application. [ABSTRACT FROM AUTHOR]

The photoionization reaction of potassium ferrocyanide has been known for a long time, yet there are few reports on the electronic structure analysis of the charge transfer to solvent (CTTS) state in this reaction. Herein, femtosecond transient absorption spectra of potassium ferrocyanide in the UV-Vis region were studied, and its photoionization under low energy excitation was observed. Using time-dependent density functional theory methods, the absorption spectra of potassium ferrocyanide were calculated in both implicit and explicit solvent models, and the electronic structure of the molecule was discussed in detail. Evidence suggests that a portion of the electron density in the CTTS state of potassium ferrocyanide is located on the empty orbital of the solvent water molecule. The vertical excitation energies calculated by the explicit solvent model are in agreement with the experimental results of the CTTS state. By elucidating the photoionization of potassium ferrocyanide from the molecular electronic structure, our results offer a method for further comprehension of the CTTS state of metal complexes and photochemical reactions. [ABSTRACT FROM AUTHOR]

With the rapid development of high-throughput sequencing technology represented by the second generation sequencing technology, whole-genome detection technology has been able to detect data from multiple levels, such as genome, transcriptome and epigenome. Biomass is a complicated regulatory system, involving many levels of complicated regulatory mechanism. Considering the limitation of single omics data analysis in exploring pathogenic factors, integrative multi-omics analysis with linear or nonlinear relationship can provide a new method for the study of the disease. Integrative analysis of multiple omics has widely used in various diseases, including lung cancer, and DNA or gene molecular level is particularly important as a basis for intermolecular correlations and complex networks. Hence, this paper briefly describes integrative analysis of genome, transcriptome and epigenome in lung cancer.