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"Li, Xuefeng"
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Effect of socioeconomic status on the healthcare-seeking behavior of migrant workers in China
In recent years, China has made great efforts to resolve the health inequality caused by household registration restrictions, and the unequal allotment of health services faced by migrant workers has been effectively alleviated. However, inequality in health services may exist not only between migrant workers and local citizens but also among migrant workers. Thus, the unbalanced utilization of health services among migrant workers deserves attention. Using data from the 2017 China Migrants Dynamic Survey (CMDS), we examined the relationship between socioeconomic status (SES) and healthcare-seeking behavior through multivariate regression analysis. Then, from the perspective of SES, this study divided migrant workers into different groups to explore the characteristics of healthcare-seeking behavior in different groups. The results showed that SES had a significant relationship with healthcare-seeking behavior. Those with high SES were more likely to use high-quality health services. By subdividing the category of migrant workers, we found that the utilization of health services among migrant workers was unbalanced. Education and income had significant gradients in multiple measures of healthcare-seeking behavior, while occupation had no significant difference in the behavior. Migrant workers with higher income and education were more likely to use high-quality health services. Especially for migrant workers who had high incomes (above 15,000 CNY) or whose educational backgrounds were graduate level or above, their utilization of health resources was significantly higher than that of other groups. When designing particular policies to improve the healthcare-seeking behavior of different SES migrant workers, we should pay attention to the low-education groups and low-income groups. Policymakers can reduce the current health inequality of migrant workers by strengthening health education and increasing medical subsidies to achieve health equality among migrant workers and between migrant workers and local citizens.
Journal Article
A study on the influence of pick geometry on rock cutting based on full-scale cutting test and simulation
In this paper, series of full-scale cutting tests and cutting simulations are carried out to investigate the influence of installation parameter and geometry of the pick on cutting performance. The discrete element method is used to simulate the rock cutting process. A general process to calibrate macro properties of rock including uniaxial compressive strength (UCS), elastic modulus, Poisson’s ratio, cohesion and internal friction angle is proposed and used to complete the calibration of coal model. The cutting simulations are performed using picks with different tip angles and rake angles. The results show that the peak cutting force (PCF) decreases with the increase of rake angle following an inverse proportional function when the rake angle is positive, while it varies following a parabolic curve in the condition of negative rake angle. Moreover, the crack mode changes from primarily shear failure to primarily tensile failure with the increase of rake angle. Finally, a multiple-attribute index is proposed to evaluate the cutting performance and select the optimum cutting parameters.
Journal Article
Development and Application of Oblique Lumbar Interbody Fusion
The present study reviewed the relevant recent literature regarding the development and application of oblique lumbar interbody fusion (OLIF), with a particular focus on its application and associated complications. The study evaluated the rationality of this technique and demonstrated the direction of future research by collecting data on previous operative outcomes and complications. A literature search was performed in Pubmed and Web of Science, including the following keywords and abbreviations: anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), direct lateral interbody fusion (DLIF), extreme lateral interbody fusion (XLIF), oblique lateral interbody fusion (OLIF), adjacent segment disease (ASD), and adult degenerative scoliosis (ADS). A search of literature published from January 2005 to January 2019 was conducted and all studies evaluating development and application of OLIF were included in the review. According to the literature, the indications for OLIF are various. OLIF has excellent orthopaedic effects in degenerative scoliosis patients and the incidence of bony fusion is higher than for other approaches. It also provides a better choice for revision surgery. It has various advantages in many aspects, but the complications cannot be ignored. As a new minimally invasive technique, the advantages of OLIF are obvious, but further evaluation is needed to compare its operation‐related data with that of traditional open surgery. In addition, more prospective studies are required to compare minimally invasive and open spinal surgery to confirm its specific efficacy, risk, advantages, learning curve, and ultimate clinical efficacy.
Journal Article
Nonlinear amplification of nano bowl surface concavity on the critical response threshold to biosignals
Polymer nanoparticles that can sharply sense and detect biological signals in cells are promising candidates for biomedical and theranostic nanomaterials. However, the response ability of current polymer assemblies poorly matches the requirement of trace concentration level (10
−6
~ 10
−9
mol/L) of cellular biosignals due to their linear signal input-to-function output mode, which impedes their practical applications in vivo. Here we report a kind of nanobowl system with pH-tunable invaginated morphology that can nonlinearly amplify the response abilities toward biosignals by modulating the surface concavity. Compared to conventional spherical nanoparticles, nonspherical nanobowls with a specific concave structure reduce the critical response threshold of polymers by up to 5 orders of magnitude, from millimole to nanomole level, covering most of biosignal concentration windows. Moreover, we find that this nonlinear signal gain effect is originated from the collective impact of a single signal on transitioning the polymer chain aggregation state of individual assemblies, rather than just altering a certain unit or chain. This nonlinear signal-to-response mechanism is potential to solve the tricky problems of probing and sensing endogenous signals with trace physiological concentration.
Polymer nanoparticles able to detect biological signals in cells at trace concentration level are desirable for practical applications in vivo. Here, the authors report nanobowl nanoparticles with a concave structure with amplified response abilities toward biosignals by the modulation of the surface concavity.
Journal Article
Free-Floating Bike Sharing in Jiangsu: Users’ Behaviors and Influencing Factors
In order to explore the factors affecting users’ behaviors in a free-floating bike sharing (FFBS) system in China, a survey was conducted in Jiangsu province, China in 2017, and the travel characteristics of FFBS users were analyzed. A binary logistic model was applied to quantify the impact of various variables regarding residents’ usage preference based on 30401 valid questionnaires. The findings show that (1) FFBS was mainly used for short-distance travel in cities, especially for commuting and schooling, and the time period of travel in FFBS coincided with the rush-hour in urban areas; (2) a higher level of education, a higher daily transportation cost, the convenience of picking up and parking, and the contribution to users’ health could promote the usage of FFBS, while malfunctioning bicycles and limited regulations were major obstacles restricting the development of FFBS; (3) interestingly, people with high-incomes rather than those with low-incomes showed an inclination for FFBS owing to the charge mode. This research provides empirical evidence to facilitate the formulation of urban transportation policies and to improve the management of FFBS for the operators.
Journal Article
Dilution-driven gel-sol-gel-sol transitions by the sequential evolution of surfactant micelles
Here are described the dilution-driven gel-sol-gel-sol transitions in aromatic hydrotrope/zwitterionic surfactant bi-component aqueous mixtures. Long and entangled wormlike micelles (WLMs) of concentrated erucyl dimethyl amidopropyl betaine (EAPB) solutions sequentially transform into hexagonal liquid crystal phase (H
1
), highly concentrated spherical micelles (HCSMs), and finally hexagonal close packed micellar phase (HCP) upon gradual introducing an aromatic hydrotrope, sodium salicylate (NaSal). The HCP then successively converts into HCSMs, WLMs, and spherical micelles (SMs) upon further dilution with water, corresponding to a gel-sol-gel-sol transition. This dilution-induced HCSMs to WLMs transition results in an interesting thickening process, which is caused by a slow kinetic process, from the agglomeration and recombination of SMs to long and rigid WLMs via the intermediately formed rodlike micelles. In this work, the sustained adjustment of the competitive self-sorting and co-assembly between hydrotropes and surfactants by dilution was identified, benefitting the creation and application of WLMs fluids with switchable viscosity.
Phase transitions are important in self-assembly process, but multiple, sequential transitions are challenging to achieve. Here, the authors report the development of the formation of wormlike micelles, which change phase following dilution to give gel-sol-gel-sol transitions.
Journal Article
Survey of Magnetic Field Parameters Associated with Large Solar Flares
Until now, how the magnetic fields in M/X-class flaring active regions (ARs) differ from C-class flaring ARs remains unclear. Here, we calculate the key magnetic field parameters within the area of high photospheric free energy density (HED region) for 323 ARs (217 C- and 106 M/X-flaring ARs), including total photospheric free magnetic energy density E free, total unsigned magnetic flux ΦHED, mean unsigned current helicity h c , length of the polarity inversion lines L PIL with a steep horizontal magnetic gradient, etc., and compare these with flare/coronal mass ejection (CME) properties. We first show the quantitative relations among the flare intensity, the eruptive character, and ΦHED. We reveal that ΦHED is a measure for the GOES flux upper limit of the flares in a given region. For a given ΦHED, there exists the lower limit of F SXR for eruptive flares. This means that only the relatively strong flares with the large fraction of energy release compared to the total free energy are likely to generate a CME. We also find that the combinations of E free–L PIL and E free–h c present a good ability to distinguish between C-class and M/X-class flaring ARs. Using determined critical values of E free and L PIL, one predicts correctly 93 out of 106 M/X-class flaring ARs and 159 out of 217 C-class flaring ARs. The large L PIL or h c for M/X-class flaring ARs probably implies the presence of a compact current with twisted magnetic fields winding about it.
Journal Article
Influence of kinematic parameters and rock properties on the cutting process with ODC based on discrete element method
This study investigates the effects of kinematic parameters and rock properties on the cutting performance of an oscillation disc cutter (ODC) based on the discrete element method. The cutting model with ODC is established using the particle flow code in three dimensions (PFC3D) and validated by experiments. Through simulation analysis, the influence of geometric parameter (eccentric ratio,
R
E
), motion parameters (velocity ratio,
R
V
) and rock characteristics on cutting crushing characteristics, cutting force and cutting efficiency is analyzed. The simulation results reveal that mean cutting force, mean torque, and specific energy (SE) increase with
R
E
and
R
V
. The mean cutting force and mean torque are positively correlated with the cutting depth and have a good linear relationship, while SE is negatively correlated with the cutting depth. Furthermore, the study demonstrates that as the cutting depth increases, the fracture mode of the rock transitions from plastic to brittle. Meanwhile, the peak cutting force occurs during the crack initiation stage and subsequently decreases during crack propagation. Finally, the multivariate regression equations of rock mechanical properties, cutting depth and SE are obtained. These findings enhance the understanding of the cutting mechanism of ODC, and provide a theoretical foundation for ODC parameter design in practical applications.
Journal Article
Verification of a novel stress path method by true-triaxial test
To verify the novel method of achieving a true-triaxial stress path with the pseudo-triaxial apparatus, a series of drained and undrained tests were carried out for the identical scheme with pseudo-triaxial apparatus and true-triaxial apparatus respectively. The differences between the two types of tests were quantified. The results show that the novel method effectively achieved the true-triaxial stress path by controlling the loading ratio of the pseudo-triaxial apparatus. The relationships of
q
−
ε
1
and
η
−
ε
s
measured by the two apparatuses had a higher similarity which decreases slightly with the
b
increase. When 0 ≤
b
< 0.5, the slope of the critical state line measured by both apparatuses was almost identical. When 0.5 ≤
b
≤ 1, the slope of the critical state line measured by the novel method was slightly lower, but the biggest change was within 10% compared with the two Mohr–Coulomb criteria, the peak strength measured by the two apparatuses was distributed near the criteria, indicating the feasibility and rationality of the novel method. The tests show that the novel method greatly enriches the test range of pseudo-triaxial apparatus, which not only simplifies the process of soil 3D testing but also reduces the test cost.
Journal Article