16 research outputs found
Human Metapneumovirus Inhibits IFN-β Signaling by Downregulating Jak1 and Tyk2 Cellular Levels
Human metapneumovirus (hMPV), a leading cause of respiratory tract infections in infants, inhibits type I interferon (IFN) signaling by an unidentified mechanism. In this study, we showed that infection of airway epithelial cells with hMPV decreased cellular level of Janus tyrosine kinase (Jak1) and tyrosine kinase 2 (Tyk2), due to enhanced proteosomal degradation and reduced gene transcription. In addition, hMPV infection also reduced the surface expression of type I IFN receptor (IFNAR). These inhibitory mechanisms are different from the ones employed by respiratory syncytial virus (RSV), which does not affect Jak1, Tyk2 or IFNAR expression, but degrades downstream signal transducer and activator of transcription proteins 2 (STAT2), although both viruses are pneumoviruses belonging to the Paramyxoviridae family. Our study identifies a novel mechanism by which hMPV inhibits STAT1 and 2 activation, ultimately leading to viral evasion of host IFN responses
An Efficient Hybrid Algorithm for Multiobjective Optimization Problems with Upper and Lower Bounds in Engineering
Generally, the inconvenience of establishing the mathematical optimization models directly and the conflicts of preventing simultaneous optimization among several objectives lead to the difficulty of obtaining the optimal solution of a practical engineering problem with several objectives. So in this paper, a generate-first-choose-later method is proposed to solve the multiobjective engineering optimization problems, which can set the number of Pareto solutions and optimize repeatedly until the satisfactory results are obtained. Based on Frisch’s method, Newton method, and weighed sum method, an efficient hybrid algorithm for multiobjective optimization models with upper and lower bounds and inequality constraints has been proposed, which is especially suitable for the practical engineering problems based on surrogate models. The generate-first-choose-later method with this hybrid algorithm can calculate the Pareto optimal set, show the Pareto front, and provide multiple designs for multiobjective engineering problems fast and accurately. Numerical examples demonstrate the effectiveness and high efficiency of the hybrid algorithm. In order to prove that the generate-first-choose-later method is rapid and suitable for solving practical engineering problems, an optimization problem for crash box of vehicle has been handled well
Crashworthiness Design for Bionic Bumper Structures Inspired by Cattail and Bamboo
Many materials in nature exhibit excellent mechanical properties. In this study, we evaluated the bionic bumper structure models by using nonlinear finite element (FE) simulations for their crashworthiness under full-size impact loading. The structure contained the structural characteristics of cattail and bamboo. The results indicated that the bionic design enhances the specific energy absorption (SEA) of the bumper. The numerical results showed that the bionic cross-beam and bionic box of the bionic bumper have a significant effect on the crashworthiness of the structure. The crush deformation of bionic cross-beam and box bumper model was reduced by 33.33%, and the total weight was reduced by 44.44%. As the energy absorption capacity under lateral impact, the bionic design can be used in the future bumper body
Crashworthiness optimization of bionic bumper structure under low-speed impact
By considering the crashworthiness design of bionic bumper structure during frontal impact, the thicknesses are chosen to analysis and optimal design to obtain the lightweight demand. The orthogonal experiment design and radial basis function are employed to construct the response surface for the performances of thin-xwalled components. The multi-objective cuckoo search (MOCS) is applied to perform the optimal design. The results demonstrate that the optimal method and process proposed have high accuracy and validity
Biobjective Optimization Algorithms Using Neumann Series Expansion for Engineering Design
In this paper, two novel algorithms are designed for solving biobjective optimization engineering problems. In order to obtain the optimal solutions of the biobjective optimization problems in a fast and accurate manner, the algorithms, which have combined Newton’s method with Neumann series expansion as well as the weighted sum method, are applied to deal with two objectives, and the Pareto optimal front is achieved through adjusting weighted factors. Theoretical analysis and numerical examples demonstrate the validity and effectiveness of the proposed algorithms. Moreover, an effective biobjective optimization strategy, which is based upon the two algorithms and the surrogate model method, is developed for engineering problems. The effectiveness of the optimization strategy is proved by its application to the optimal design of the dummy head structure in the car crash experiments
Crashworthiness optimization of bionic bumper structure under low-speed impact
By considering the crashworthiness design of bionic bumper structure during frontal impact, the thicknesses are chosen to analysis and optimal design to obtain the lightweight demand. The orthogonal experiment design and radial basis function are employed to construct the response surface for the performances of thin-xwalled components. The multi-objective cuckoo search (MOCS) is applied to perform the optimal design. The results demonstrate that the optimal method and process proposed have high accuracy and validity
Multifunctional Flexible Ionic Skin with Dual-Modal Output Based on Fibrous Structure
Flexible wearable electronic devices with multiple sensing
functions
that simulate human skin in all aspects have become a popular research
topic. However, the current expensive and time-consuming means of
integration and the complex decoupling process are hampering the further
development of multifunctional sensors. Here, an ultraflexible ionic
fiber membrane (IFM) prepared by a simple electrospinning technique
is reported, which exhibits pressure and humidity sensing properties.
With the help of different electrode structures, the IFM-based multifunctional
sensor achieved pressure and humidity detection with different sensing
mechanisms. Pressure sensing with high sensitivity (49.7 kPa–1 at 0–30 kPa) and wide detection range (0–220 kPa)
was indicated by the capacitive signal. Humidity sensing with high
linearity (1.086% per percent relative humidity (RH)) in the range
15%–90% RH was indicated by the resistance signal. In particular,
the multimodal output of capacitance/resistance corresponding to pressure/humidity
in this study directly addresses the problem of accurately distinguishing
the two stimuli. Furthermore, we have demonstrated that the impact
between pressure and humidity is negligible when measured simultaneously
and independently. Because of the excellent pressure/humidity sensing
performance, we have fabricated a smart bracelet and mask for pulse,
skin moisture, and breathe monitoring, which indicates the promising
future of multifunctional flexible sensors based on IFM in the healthcare
field