Exploration of the influence of different biomimetic designs of 3D printed multi-material artificial spinal disc on the natural mechanics restoration

One of the great challenges of artificial spinal disc (ASD) design lies in the reproduction of the complex mechanics of an intervertebral disc (IVD) that is characterized by a viscoelastic, nonlinear, and anisotropic behavior. Although the development of multi-material additive manufacturing (AM) combined with biomimetic design provide new opportunities for the realization of ASDs with complex behavior, the influence of different biomimetic designs on the kinematics of ASD in conjunction with AM is not yet explored. Therefore, this study proposes and fabricates four types of biomimetic, multi-material ASD designs based on mimicking either the material stiffness gradient or the structure found in a natural IVD. The results show that all the designs exhibit a desired viscoelastic behavior, while the ASD design based on a chainmail-like structure exhibits a nature-mimicking nonlinear rotational load response. In terms of restoring the natural trend of IVD’s anisotropic behavior, the ASD design that mimics the structure in an IVD outperforms the design that solely mimics the IVD’s material stiffness gradient. Additionally, all the designs proposed in this study show comparable instant helical axis (IHA) and instant center of rotation (ICOR) to an IVD regarding their location and moving direction

Fuzzy evaluation of low carbon development levels for logistic enterprises in China

Purpose: Under the background of global warming, low carbon economy, which is based on low waste and low pollution, has become a globally focused topic. Energy conservation, emission reduction and low carbon development have become irresistible trends of social development. A new set of low carbon evaluation index system for logistics enterprises is proposed. It is helpful for the better monitor of low carbon production and provide the optimization of industrial policies in China. Design/methodology/approach: Based on the problem that logistic analyses are facing under the background of low carbon economy, this paper firstly establishes a set of new evaluation indexes system, including 5 first-level indices and 28 second-level indices, for the low carbon development levels of logistics enterprises in China. To simplify the new evaluation system, the weight judgment method is then used to select indices, the validity judgment method and reliability coefficient judgment method are respectively used to test the validity and reliability of the evaluation systems. The simplified evaluation system consists of 4 first-class indices and 20 second-class indexes. Finally, numerical examples illustrate the validity and operability of the evaluation system. Findings: From the analysis and evaluation results, it is not difficult to obtain the rank of logistics enterprise according to the selected indexes or the overall evaluation indices. Low scores of some key indexes in strategy indices and technical indices cause low carbon emission performance. Moreover, The reason for the good low carbon performance of one enterprises is that it is in the lead on the key indexes of high weighs such as Perfection degree of low carbon development strategy, Level of transportation route optimization, etc. The new evaluation index system also helps enterprises to realize the sustainable development by identifying the key factors that affect the low carbon development level. Originality/value: The existing literature that assesses low carbon logistics is mostly focused on the review of the location-based and industry-based aspects, and little attention has been paid to assessing the efficiency of low carbon logistics from the components that are within the logistics enterprises. Therefore, we develop a new low carbon evaluation index system for logistics enterprises in order to better monitor low carbon production and provide the optimization of industrial policies in China.Peer Reviewe

Liquid metal embrittlement of a dual-phase Al0.7CoCrFeNi high-entropy alloy exposed to oxygen-saturated lead-bismuth eutectic

This paper reports a new liquid metal embrittlement (LME) system in which a dual-phase Al0.7CoCrFeNi (equimolar fraction) high-entropy alloy (HEA) is embrittled by lead-bismuth eutectic (LBE) at 350 and 500°C. At 350°C, (Ni, Al)-rich BCC phase is embrittled, leading to intragrain cracking within this phase, while the predominant cracking mode changes to BCC/FCC phase boundary decohesion at 500°C. At both temperatures, cracks are rarely seen in the (Co, Cr, Fe)-rich FCC phase, indicating that this phase is immune to LME. Furthermore, the results suggest a transition from an adsorption-dominated LME mechanism at 350°C to a phase boundary wetting-dominated LME mechanism at 500°C

Immune Protection Induced on Day 10 Following Administration of the 2009 A/H1N1 Pandemic Influenza Vaccine

BACKGROUND: The 2009 swine-origin influenza virus (S-OIV) H1N1 pandemic has caused more than 18,000 deaths worldwide. Vaccines against the 2009 A/H1N1 influenza virus are useful for preventing infection and controlling the pandemic. The kinetics of the immune response following vaccination with the 2009 A/H1N1 influenza vaccine need further investigation. METHODOLOGY/PRINCIPAL FINDINGS: 58 volunteers were vaccinated with a 2009 A/H1N1 pandemic influenza monovalent split-virus vaccine (15 µg, single-dose). The sera were collected before Day 0 (pre-vaccination) and on Days 3, 5, 10, 14, 21, 30, 45 and 60 post vaccination. Specific antibody responses induced by the vaccination were analyzed using hemagglutination inhibition (HI) assay and enzyme-linked immunosorbent assay (ELISA). After administration of the 2009 A/H1N1 influenza vaccine, specific and protective antibody response with a major subtype of IgG was sufficiently developed as early as Day 10 (seroprotection rate: 93%). This specific antibody response could maintain for at least 60 days without significant reduction. Antibody response induced by the 2009 A/H1N1 influenza vaccine could not render protection against seasonal H1N1 influenza (seroconversion rate: 3% on Day 21). However, volunteers with higher pre-existing seasonal influenza antibody levels (pre-vaccination HI titer ≥1∶40, Group 1) more easily developed a strong antibody protection effect against the 2009 A/H1N1 influenza vaccine as compared with those showing lower pre-existing seasonal influenza antibody levels (pre-vaccination HI titer <1∶40, Group 2). The titer of the specific antibody against the 2009 A/H1N1 influenza was much higher in Group 1 (geometric mean titer: 146 on Day 21) than that in Group 2 (geometric mean titer: 70 on Day 21). CONCLUSIONS/SIGNIFICANCE: Recipients could gain sufficient protection as early as 10 days after vaccine administration. The protection could last at least 60 days. Individuals with a stronger pre-existing seasonal influenza antibody response may have a relatively higher potential for developing a stronger humoral immune response after vaccination with the 2009 A/H1N1 pandemic influenza vaccine