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Stability control for soft and broken surrounding rock of roadways is one important segment of mining support. Taking 1412 Roadway of a mine in Guizhou province as a research background, this paper studies the large deformation of surrounding rock and the failure of bolts and cables. The deformation and failure mechanism are analyzed by related theoretical analysis and field survey. Then, the feasibility of the composite controlling scheme, bolts and cables + grouting + steel tube concrete support, is verified by theoretical analysis, numerical simulation, and industrial test. Following results can be obtained: main reasons leading to the deformation of surrounding rock and the failure of cables and blots in the roadway are low strength and poor self-stability of surrounding rock, complex stress environment, low support resistance, and lack of reinforced support in crucial supporting sites; the control scheme can reduce the surrounding rock deformation by 40%, which meets the requirements of field application so that this practice can provide some guidance for other similar projects.

Jiaxiu Liu,1,2 Ruibin Deng,1 Bing Lin,1 Hong Pan,1 Yuwen Gao,1 Jianghong Dai,3 Hao Liang,4 Ailong Huang,5 Xiaoni Zhong1 1School of Public Health and Management, Chongqing Medical University, Chongqing, 400016, People’s Republic of China; 2School of Medical Information, Chongqing Medical University, Chongqing, People’s Republic of China; 3Department of Epidemiology and Health Statistics, School of Public Health, Xinjiang Medical University, Xinjiang, People’s Republic of China; 4Department of Epidemiology and Medical Statistics, School of Public Health, Guangxi Medical University, Nanning, People’s Republic of China; 5Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing, People’s Republic of ChinaCorrespondence: Xiaoni ZhongSchool of Public Health and Management, Chongqing Medical University, 1 Yixue Road, Chongqing, 400016, People’s Republic of ChinaTel +86 13308368059Email zhongxiaoni@cqmu.edu.cnBackground: Men who have sex with multiple men (MSMM) belong to a high-risk group for HIV infection, and pre-exposure prophylaxis (PrEP) is an effective measure to prevent the infection. However, few studies on PrEP adherence by MSMM in China exist. We aimed to explore the protective motivation-related factors for PrEP adherence in an HIV-negative MSMM population in Western China and to provide a reference for future risk management and effective prevention strategies.Methods: Data were collected from a 2-year follow-up cohort study of PrEP in MSM in China. Rogers’ protective motivation theory (PMT) was used to study the PrEP adherence of MSMM, and logistic regression was performed to analyze the influencing factors of PrEP adherence.Results: A total of 496 MSMM were included in the study: 299 (60.28%) of them in the good adherence group and 197 (39.72%) in the poor adherence group. The threat assessment scores of the good and poor adherence groups were 2.15 ± 0.59 and 2.06 ± 0.47, respectively, and the response assessment scores were 2.81 ± 0.62 and 2.74 ± 0.62, respectively. Poor PrEP adherence was associated with on-demand PrEP medication (OR=0.670), students at school (OR=1.837), occasional condom use (OR=1.621), and good HIV knowledge (OR= 0.659). The higher the threat assessment score, the higher the susceptibility; and the lower the response cost, the stronger the protection motivation and the less likely MSMM were to have poor adherence.Conclusion: On-demand PrEP medication is more conducive to adherence. Preventive management should focus on MSMMs who are students at school, those who occasionally use condoms, and those with poor HIV knowledge. Improving threat perception and susceptibility, and controlling and reducing the response cost can effectively improve PrEP adherence, and the subsequent application of PMT during intervention research can provide a reference for HIV prevention in MSMM.Keywords: MSM, multiple sexual partners, PrEP, adherence, protective motivation theory, Western China

(1) Background: Few studies have explored the heterogeneity of trajectories of stress, anxiety, and depressive symptoms during pregnancy. This study aimed to explore the trajectory groups of stress, anxiety, and depressive symptoms in women during pregnancy and the risk factors associated with those groups. (2) Methods: Data came from pregnant women recruited from January to September 2018 in four hospitals in Chongqing Province, China. A structured questionnaire was given to pregnant women, which collected basic information, including personal, family, and social information. The growth mixture model was applied to identify potential trajectory groups, and multinomial logistic regression was applied to analyze factors of trajectory groups. (3) Results: We identified three stress trajectory groups, three anxiety trajectory groups, and four depression trajectory groups. Less developed regions, inadequate family care, and inadequate social support were associated with a high risk of stress; residence, use of potentially teratogenic drugs, owning pets, family care, and social support were strongly associated with the anxiety trajectory group; family care and social support were the most critical factors for the depression trajectory group. (4) Conclusions: The trajectories of prenatal stress, anxiety, and depressive symptoms are dynamic and heterogeneous. This study may provide some critical insights into the characteristics of women in the high-risk trajectory groups for early intervention to mitigate worsening symptoms.

In contrast to traditional large-scale robots, which require complicated mechanical joints and material rigidity, microrobots made of soft materials have exhibited amazing features and great potential for extensive applications, such as minimally invasive surgery. However, microrobots are faced with energy supply and control issues due to the miniaturization. Magnetic field actuation emerges as an appropriate approach to tackle with these issues. This review summarizes the latest progress of biomimetic soft microrobots actuated by magnetic field. Starting with an overview of the soft material and magnetic material adopted in the magnetic field actuated soft microrobots, the various fabrication methods and design structures of soft microrobots are summarized. Subsequently, practical and potential applications, such as targeted therapy, surgical operation, and the transportation of microscopic objects, in the fields of biomedicine and environmental remediation are presented. In the end, some current challenges, and the future development trends of magnetic soft microrobots are briefly discussed. This review is expected to offer a helpful guidance for the new researchers of biomimetic soft microrobots actuated by magnetic field.

Background A high rate of cesarean delivery has become a cause of global concern. Although the rate of cesarean delivery has declined over recent years, it remains at a high level largely because of cesarean delivery on maternal request (CDMR). Unnecessary cesarean delivery has limited significance in benefiting maternal and infant physical health; in some ways, it might pose potential risks instead. With the implementation of the “Two-child Policy” in China, an increasing number of women plan to have a second child. Accordingly, how to handle the CDMR rate in China remains an important issue. Methods Data were collected from a longitudinal follow-up study conducted in Chongqing, China, from 2018 to 2019. A structured questionnaire was administered to subjects for data collection. Basic information, including demographic characteristics, living habits, medical history, and follow-up data of pregnant women, as well as their families and society, was collected. Additionally, delivery outcomes were recorded. Logistic regression was performed to analyze the factors influencing CDMR. Results The rate of cesarean delivery in Chongqing, China was 36.01 %, and the CDMR rate was 8.42 %. Maternal request (23.38 %), fetal distress (22.73 %), and pregnancy complications (9.96 %) were the top three indications for cesarean delivery. Logistic regression analysis showed that older age (OR = 4.292, 95 % CI: 1.984–9.283) and being a primiparous woman (OR = 6.792, 95 % CI: 3.230-14.281) were risk factors for CDMR. In addition, CDMR was also associated with factors such as the tendency to choose cesarean delivery during late pregnancy (OR = 5.525, 95 % CI: 2.116–14.431), frequent contact with mothers who had undergone vaginal deliveries (OR = 0.547, 95 % CI: 0.311–0.961), and the recommendation of cesarean delivery by doctors (OR = 4.071, 95 % CI: 1.007–16.455). Conclusions “Maternal request” has become the primary indication for cesarean delivery. The occurrence of CDMR is related to both the personal factors of women during pregnancy and others. Medical institutions and obstetricians should continue popularizing delivery knowledge among pregnant women, enhancing their own professional knowledge about delivery, adhering to the standard indications for cesarean delivery, and providing pregnant women with adequate opportunities for attempting vaginal delivery.

Additional file 1. Questionnaires for the collection of basic information and follow-up data throughout the pregnancy

In order to improve the product quality of crops, the characteristics of the selenium-rich soil in the heavy metal high background area and its impact on the main crops are studied. Analyze the bioavailability and existence of selenium element, and obtain the classification standard of soil selenium content. Taking Shitai County in Anhui Province as the research area, soil samples from this area were collected, and the results of the collection were made into a field sampling report. The sampling results were analyzed by statistical methods to obtain the measurement results of the selenium content in the soil of the study area. Finally, the LSMM model was established to realize the effective analysis of the characteristics of selenium-rich soil in the heavy metal high background area. The research results show that under different heavy metal pollution conditions, the growth of corn, rice and soybean crops is different. Generally speaking, heavy metals will restrict the healthy growth of crops; the effect of selenium absorption activity will directly or indirectly affect the growth and development of crops; the selenium enrichment rate of crops shows the characteristics of corn>rice>soybeans.

The performance of shaking tables and their control systems are key elements to achieve the objects of a seismic vibration test simulation. In this paper, the methodology of a vibration test on reduced scale test specimens with a small scale electromagnetic shaking table has been proposed. For the influence of test specimens and table structure over the table output signal, this method optimizing the non-linear correction of signals driven by the shaking table so as to reduce the distortion degree of the table output excitation parameters has been discussed. The solutions of the preprocessing of input signals, post-processing of output signals, and analyzing test data targeted at the structural features of reduced-scaled test specimens has also been put forward.