The ground vibration mitigation effects of pile barriers in unsaturated ground were analysed numerically. The numerical model for the ground was established using the boundary element method (BEM) ...with the soil being simulated as the unsaturated poroviscoelastic medium. To solve the boundary element governing equations, the fundamental Green solutions of the unsaturated medium was derived using the properties of the adjoint matrix. The numerical model of the scattering piles was established using the Timoshenko beam, and solved by the finite element method (FEM). The coupled model of the unsaturated ground and pile barrier was obtained using the displacement compatibility and force equilibrium conditions. The influences of soil saturation degree under various pile parameters to the mitigation effects were studied using the proposed approach. This research found the increasing ground saturation degree improves the effects of the pile barrier, especially for the high frequency vibrations. And the effects of the saturation degree can be affected by the pile length or pile distance.
The technique of attaching the polymer polyethylene glycol (PEG), or PEGylation, has brought more than ten protein drugs into market. The surface conjugation of PEG on proteins prolongs their blood ...circulation time and reduces immunogenicity by increasing their hydrodynamic size and masking surface epitopes. Despite this success, an emerging body of literature highlights the presence of antibodies produced by the immune system that specifically recognize and bind to PEG (anti-PEG Abs), including both pre-existing and treatment-induced Abs. More importantly, the existence of anti-PEG Abs has been correlated with loss of therapeutic efficacy and increase in adverse effects in several clinical reports examining different PEGylated therapeutics. To better understand the nature of anti-PEG immunity, we summarize a number of clinical reports and some critical animal studies regarding pre-existing and treatment-induced anti-PEG Abs. Various anti-PEG detection methods used in different studies were provided. Several protein modification technologies beyond PEGylation were also highlighted.
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► We compare non-ionic poly (ethylene glycol) (PEG) with zwitterionic poly(carboxybetaine) (PCB) in creating stealth nanoparticles. ► Both polymers exhibit good non-fouling properties ...due to strong hydration. ► Amphiphilic PEG has negative effects on proteins and nanoparticles due to its hydrophobic nature. ► PCB overcomes these problems due to its super-hydrophilic nature.
This review compares two types of non-fouling polymers, the widely used non-ionic poly(ethylene glycol) (PEG) and the recently established zwitterionic poly(carboxybetaine) (PCB), for their use in creating stealth nanoparticles (NPs) for drug delivery and protein protection. While both types of polymers exhibit reasonable non-fouling properties, such as good protein and colloidal stability and extended blood circulation time in vivo, amphiphilic PEG has negative effects on proteins and NPs due to its hydrophobic nature, including reduced protein bioactivity, instability of assembled NPs, and lipid bilayer destabilization. These problems can be overcome by super-hydrophilic PCB.
With the rapid development of deep learning techniques, deep convolutional neural networks (DCNNs) have become more important for object detection. Compared with traditional handcrafted feature-based ...methods, the deep learning-based object detection methods can learn both low-level and high-level image features. The image features learned through deep learning techniques are more representative than the handcrafted features. Therefore, this review paper focuses on the object detection algorithms based on deep convolutional neural networks, while the traditional object detection algorithms will be simply introduced as well. Through the review and analysis of deep learning-based object detection techniques in recent years, this work includes the following parts: backbone networks, loss functions and training strategies, classical object detection architectures, complex problems, datasets and evaluation metrics, applications and future development directions. We hope this review paper will be helpful for researchers in the field of object detection.
A new method of multi-sensor signal analysis for fault diagnosis of centrifugal pump based on parallel factor analysis (PARAFAC) and support vector machine (SVM) is proposed. The single-channel ...vibration signal is analyzed by Continuous Wavelet Transform (CWT) to construct the time-frequency representation. The multiple time-frequency data are used to construct the three-dimension data matrix. The 3-level PARAFAC method is proposed to decompose the data matrix to obtain the six features, which are the time domain signal (mode 3) and frequency domain signal (mode 2) of each level within the three-level PARAFAC. The eighteen features from three direction vibration signals are used to test the data processing capability of the algorithm models by the comparison among the CWT-PARAFAC-IPSO-SVM, WPA-PSO-SVM, WPA-IPSO-SVM, and CWT-PARAFAC-PSO-SVM. The results show that the multi-channel three-level data decomposition with PARAFAC has better performance than WPT. The improved particle swarm optimization (IPSO) has a great improvement in the complexity of the optimization structure and running time compared to the conventional particle swarm optimization (PSO.) It verifies that the proposed CWT-PARAFAC-IPSO-SVM is the most optimal hybrid algorithm. Further, it is characteristic of its robust and reliable superiority to process the multiple sources of big data in continuous condition monitoring in the large-scale mechanical system.
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•A zwitterionic polymer-protein conjugate does not elicit polymer-specific antibodies.•It alleviates anti-drug antibodies.•It improves upon the pharmacokinetics of native and ...polyethylene glycol conjugates.
Proteins are promising therapeutics with several design challenges, such as their inherent immunogenicity due to their exogenous source or short circulation time. The common solution to such issues is the chemical conjugation of the amphiphilic polymer poly(ethylene glycol) (PEG), a process known as PEGylation. However, several studies demonstrated a decrease in protein bioactivity or an increase in the presence of specific antibodies post PEGylation, highlighting the importance of an alternative strategy. Here we compare the performance of a superhydrophilic zwitterionic polymer in protecting an immunogenic protein to PEG in (i) the maintenance of enzyme activity and stability post modification, (ii) mitigation of the antibody response elicited by the polymer and any subsequent effect on pharmacokinetics, and (iii) minimization of host response toward the underlying protein. In contrast to PEG, zwitterionic conjugation decreases host antibody response without sacrificing bioactivity or generating polymer-specific antibodies.
The elastic wave propagation and vibration attenuation zones for periodically scattering piles in unsaturated ground were investigated using Finite-Element Method (FEM) and Bloch periodic theory. The ...unsaturated ground was modelled by unsaturated poroviscoelastic medium with the weak form governing equations derived from the mass and momentum conservative equations using Galerkin method and Fourier transform. The quadratic polynomial eigenvalue equations for the unsaturated medium were obtained using the Bloch periodic theory, and solved by FEM for the complex eigenvalues to evaluate the band gaps of the pile-soil system. The eigenvalue bands combined with the frequency response function were used to analyse the mitigation effects of piles in unsaturated ground with different soil properties and piles parameters. This research found that the pile-soil system has three propagational waves, in which the shear wave and the slow longitudinal wave carry low-frequency vibrations that undermine the attenuation effects of the piles barrier. The increasing soil saturation degree affects the attenuation effects by reducing the soil modulus and increasing the fluid content. And both of those two mechanisms reduce the frequency of the attenuation zones (AZ), which improves the low-frequency vibration attenuation, and reduces the width of AZ that could reduce the vibration mitigation effects.
Abstract In this work, we report a new approach to integrate antimicrobial and nonfouling properties into a single platform without compromising each other. To achieve this, a zwitterionic hydrogel ...is conjugated with an antimicrobial agent as a leaving group in a way that maintains the zwitterionic form of the hydrogel before, during and after drug release, preventing bacteria surface adhesion and bulk proliferation simultaneously. The antibacterial salicylate anion contributes the negative charge to the initial zwitterionic state and is released through the ester linkage hydrolysis. The hydrogel then switches to its final zwitterionic state with the carboxylate as its new negatively charged group. We prove that this hydrogel can reach one-salicylate-per-monomer drug loading while still retaining the nonfouling property at protein and bacteria levels. It was also shown that its drug release profile was dictated by the hydrolysis rate of the monomer, making it possible to control and tailor the release rate of small hydrophilic drugs from the highly hydrated nonfouling polymer matrix.
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