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The coal-bearing sequences of the Late Permian in southwest China are enriched in critical elements Sc, V, Co, Ni, Cu, Zn, Nb, Ta, Zr and Hf. Ascertaining the conditions and basis for the enrichment of critical elements in this area is very important to support the critical metal demands of China. In this study, we analyzed the concentrations of elemental compositions of coal samples collected from the Late Permian Guishan coalfield in the eastern Yunnan, China. The results show that the C4-Upper coal seam of the Feilongma mine and C5 + 10 coal seam of the Shipeng mine are indeed rich in critical elements. The average concentration coefficients (CC) of transition metal elements Sc, V, Co, Ni, Cu, and Zn are 3.23 and 2.93, respectively, in the two coal seams. The average CCs of high-field-strength elements Nb, Ta, Zr, and Hf and non-variable valence chalcophile elements Ga and In are 2.21 and 2.53, respectively, in the two coal seams. The C4-Upper coal seam of the Feilongma mine can be divided into two sections based on the different ash contents, and the CCs of the critical elements in the two sections are almost equal. The main minerals in the two coal seams are kaolinite, siderite, quartz, gypsum, rozenite and marcasite. Multiple indicators of provenance show that the enrichment of critical elements in the Guishan coalfield is controlled by clastic terrigenous material. The source area of the Guishan coalfield is Kangdian Oldland in the northwest, and the main clastic materials are related with high-Ti basalts from the Emeishan Large Igneous Province. [ABSTRACT FROM AUTHOR]

In this paper, according to the characteristics of rock salt deposits and surrounding rock in the Ningjin area of Hebei, China, layered transfer theory and modified probability integral theory are used to conduct an in-depth study and quantitative evaluation of the surface deformation characteristics of the study area. The main conclusions are as follows: the calculation results of the layered transfer model show that as the cavity increases, the settlement of the center point of the surface increases from 59 to 227 mm in the range of 100–1500 m, and the maximum influence area of the surface reaches 1.30 × 107 m2. The calculation results of the modified probability integral theory model show that as the mined cavity increases, the settlement of the surface center point increases from 23 to 351 mm in the range of 100–1500 m, and the maximum surface influence area reaches 1.04 × 107 m2. The results of the two theoretical calculations accurately indicate the relationship between the mining cavern and the surface subsidence and the influence range of the surface, which has important guiding significance for the safe mining of Ningjin salt mines. [ABSTRACT FROM AUTHOR]

Traditional machine tool reliability modeling methods take static parts as the research object, ignoring the characteristic that the function and performance of computer numerical control (CNC) machine tool are ultimately driven by its most basic actions, and the traditional reliability modeling methods do not fully consider the randomness of machine tool failure. In view of this, this paper gave an improved four‐parameter nonhomogeneous Poisson process reliability modeling method based on meta‐action (MA), and a comprehensive method of system reliability was presented. A CNC machine tool made in China was taken as an example, and the reliability model of MA and the whole machine were built by the proposed method. The proposed method was compared with other methods by Akaike information criterion and Bayesian information criterion, and the method proposed in this paper was proved to be better. The reliability indexes of the system were simulated, and then the general trend of system reliability indexes was obtained by least squares support vector machines. The results verify the applicability and validity of this method, and lay a foundation for further research on the machine tool reliability based on metamotion. [ABSTRACT FROM AUTHOR]

Frequent early failures are the key factors restricting the reliability improvement of CNC (computer numerical control) machine tools. In order to eliminate the early failures of CNC machine tools as much as possible, this paper defined the early failures of CNC machine tools strictly and divided the early failures into sudden early failures and progressive early failures. According to the characteristics of sudden early failures, the corresponding reliability analysis model was established by fishbone diagram and 5M1E (man, machine, material, method, measurement, environment) method. Based on the failure time rather than failure time intervals, the reliability analysis model of progressive early failures, which can reflect the dynamic characteristics of CNC machine tool failures, was established by BBIP (bounded bathtub intensity process) method in NHPP (non-homogeneous Poisson process). The reliability evaluation indexes of progressive early failures were given, and the analysis method of the influence of the relationship between former failure and latter failure on the established reliability model was given. CNC machine tools made in China were taken as the example, and the reliability analysis models of sudden early failures and progressive early failures were established and analyzed, respectively. The conclusion that different product failures of the same model could not be analyzed by the same parameter model is obtained. The results also verify the applicability and correctness of the proposed method, which lay a foundation for the elimination of early failure and the improvement of reliability of machine tools. [ABSTRACT FROM AUTHOR]

Early faults of product have plagued many machine tool companies, especially middle-small enterprises limited by capital. To eliminate the early faults and improve the reliability of computerized numerical control (CNC) machine tools, we propose a systematic early fault elimination method based on the after-sale data (customer field data) of CNC machine tools. The proposed method includes four steps: fault data collection; a four-parameter non-homogenous Poisson process (NHPP) model; a mixed fault analysis method that is the combination of fault tree analysis (FTA) method and fault mode, effects, and criticality analysis (FMECA) method; and early fault elimination measures. The first step is the basis of the analysis. The second step is used to determine the early faults from the fault data. The third step is to analyze the early faults determined. Risk priority number (RPN) is calculated to assess the criticality of the fault causes determined by the FTA. The elimination measures are taken in the end. We apply our method to a machine tool company in China, and the results prove the practicality and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Background. Portal vein tumor thrombosis (PVTT) is one of the major predictive factors for patients with hepatocellular carcinoma (HCC). The objective of this study was to establish a prognostic nomogram for identifying individual survival outcomes in patients with HCC and PVTT on conservative treatment based on specific factors. Methods. Two hundred and ten patients with HCC and PVTT on conservative treatment in Beijing Ditan Hospital between June 2008 and May 2017 were studied retrospectively as a derivation cohort. We built a nomogram based on independent risk factors for survival prediction. The concordance index (c-index) and a calibration curve were used to evaluate the predictive accuracy. During the study, 102 patients were included at the Putuo Hospital and Third People's Hospital of Changzhou as a validation cohort. Results. In the derivation cohort, the independent factors for overall survival were identified by multivariate analysis, namely, aspartate aminotransferase ≥119 IU/L, gamma-glutamyl transferase ≥115 IU/L, Child–Pugh class C liver function, creatinine ≥91 μmoI/L, α-fetoprotein ≥400 ng/ml, and largest tumor diameter ≥5 cm. The nomogram had a c-index of 0.737 (95% confidence interval, 0.692–0.782) and the calibration curves fitted well. The median survival time was 4.2 months in the derivation cohort, with an MST of 5 months for BCLC C stage and 1.8 months for BCLC D stage patients. Kaplan–Meier analysis showed significant statistical differences in the 6-month overall survival rates of the primary and validation cohorts after the total scores were divided into three quartiles (low risk: 0–85; intermediate risk: 86–210; high risk: ≥211; p < 0.0001 in both cohorts). Conclusions. The nomogram can be a more accurate and individualized prediction for 6-month overall survival of patients with HCC and PVTT on conservative treatment, and it is possible to consider further active interventions for patients in the low-risk group (0–85 scores) to achieve the aim of prolonging survival. [ABSTRACT FROM AUTHOR]

The current decomposition methods are not suitable for electromechanical product; the smallest decomposition units obtained by these methods are static parts or components, which cannot reflect the characteristics of electromechanical product that 'action determines motion, and motion determines function'. Meta‐action is the smallest action to realize the function of electromechanical product, and it is reasonable to regard meta‐action as the smallest decomposition unit of electromechanical product. Meta‐action unit is the smallest structural unit to ensure the normal operation of meta‐action, and it is also the smallest carrier of electromechanical product quality characteristics. Meta‐action unit modeling technology is the basis of other subsequent research, so it is necessary to study it. In this paper, detailed criteria for meta‐action decomposition and meta‐action unit separation are formulated, and the standardized structural model, symbolized conceptual model, and assembly model of meta‐action unit are also studied, which provide a basis for mechanical, kinematic, and failure mechanism research of electromechanical product. A CNC (computer numerical control) machine tool made in China is taken as an example for meta‐motion decomposition and meta‐action unit modeling, and the results verify the applicability and correctness of the method proposed in this paper. The proposed method is also applicable to other types of electromechanical product. [ABSTRACT FROM AUTHOR]

The reliability of machine tool is getting more and more attention. Reasonable reliability allocation is beneficial to improve the inherent reliability of machine tool. However, the existing reliability allocation methods for machine tool have some limitations. For example, static part is selected as the reliability allocation object of machine tool, which cannot reflect the characteristics "function realized by motion"; factors affecting reliability allocation are not considered comprehensively, weights of experts are treated as the same, and the allocation results are not optimized or the impact of time on enterprise is neglected in the optimization. To solve these problems, a new multiobjective optimization reliability allocation method for machine tool is proposed in this paper. Firstly, the latest achievements about meta‐action are given, and meta‐action is set as the reliability allocation object. Secondly, more reasonable and comprehensive factors affecting reliability allocation are extracted. Thirdly, expert weight coefficient is brought to reduce the subjective impact of expert scoring. Fourthly, time factor is brought to make the optimized allocation results more reasonable and accurate. Finally, a numerical control (NC) machine tool made in China is taken as an example, with a comparison on the reliability allocation results of current methods and proposed method. The results verify the applicability, rationality, and accuracy of the proposed method, which lays a foundation for the subsequent study on the quality characteristics of machine tool based on meta‐action. [ABSTRACT FROM AUTHOR]

• A more reasonable analysis object (meta-action and meta-action unit) is selected. • A failure mode quantitative judgment method based on meta-action is proposed. • A new failure cause and mechanism modeling method based on meta-action is proposed. Early failure is the key factor that restricts the improvement of electromechanical product reliability. The research on early failure mechanism of electromechanical product can provide a basis for the subsequent failure cause tracing and failure diagnosis. At present, there are few systematic studies on the early failure mechanism of electromechanical product, which have the following shortcomings: firstly, the failure analysis objects in traditional failure methods cannot reflect the characteristic of electromechanical product that "motion determination electromechanical product function"; secondly, traditional failure analysis methods ignore the fact that mechanical and electronic systems are different in failure cause, failure mode and failure mechanism; thirdly, failure cause and failure mode are easily confused in traditional methods; finally, most of the traditional methods are qualitative analysis, which cannot directly show the generation process of failure. To address those problems, meta-action and meta-action unit of electromechanical product are selected as the analysis object herein. Early failure mode, early failure cause, and early failure mechanism of electromechanical product are defined and analyzed. A meta-action early failure mechanism quantitative analysis model considering electromechanical coupling is built, and the influence of failure cause on failure mode is analyzed. A CNC (computer numerical control) machine tool made in China is taken as an example. The results verify the applicability and correctness of the proposed method. [ABSTRACT FROM AUTHOR]

The adjustment of administrative division is one of the powerful tools used to promote urbanization by the Chinese government in recent decades, and there is little literature to discuss whether the government-led expansion of urban space through city-county mergers can bring about a decline in urban energy intensity. With the multi-period difference-in-differences (DID) method and comprehensive urban datasets, this research investigates the urban energy intensity results of the city-county mergers policy experiment in China from 2000 to 2017. We present evidence that city-county mergers are indeed beneficial in reducing urban energy intensity, and that the energy-saving effect of the policy only starts to become significant in the third year after implementation. We also further adopt a series of robustness tests, such as the counterfactual test, placebo tests and PSM-DID tests to find if this effect still exists. The mechanism test with mediating effects indicates they are potential contributors to the positive effects of mergers with moderate fiscal centralization, population agglomeration and regional integration. We further explore positive effects of mergers, relying on the scientifically design official appraisal system and improve government efficiency.

Purpose: Little is known about emergency hospitalizations owing to adverse drug events (ADEs) in Chinese populations. The aim of this study was to identify the types and characteristics of ADEs as well as estimate the length of hospital stay and ADE-related costs in a hospital emergency setting in China., Methods: This prospective study was conducted in the emergency department of our hospital from April 1, 2017 to December 31, 2019. ADEs of patients admitted to the emergency department were collected by a clinical pharmacist during daily pharmacy rounds., Results: Of 4020 cases admitted to the emergency department, 198 emergency ADE-related hospitalizations (4.93%) were noted, which were classified into certain (n = 0, 0%), probable (n = 122, 61.6%), and possible (n = 76, 38.4%). The ADE was serious in 93.9% of the 198 cases. Ten cases were fatal, and two cases were life-threatening. More than 80% of the emergency ADE-related hospitalization cases were of patients over 60 years. The pharmacological agents implicated in the hospitalizations were oral antiplatelet agents (20.7%), oral hypoglycemic agents (16.7%), insulin (11.1%), and antihypertensive agents (9.1%). The average length of ADE-related hospital stay was 10 (7.0-14.0) days. ADE-related costs ranged from $1684.68 to $4531.35 for each hospitalization. The length of ADE-related hospital stay and associated costs were statistically significant. Most ADEs (n = 146, 73.7%) were preventable., Conclusions: Most emergency ADE-related hospitalizations in older adults resulted from lack of medication monitoring or inappropriate medication. Improved management of medicines by clinical pharmacists has the potential to reduce ADE-related hospitalizations in older adults in China., (© 2021 John Wiley & Sons Ltd.)

BACKGROUND Patients with hip joint infections in childhood often have many aftereffects of different degrees, regardless of the kind of treatment or natural course. Total hip arthroplasty is currently the most effective treatment for sequelae of childhood hip septic or tuberculous infection. This is a mid-term follow-up study of treatment results of patients who had undergone total hip arthroplasty (THA) with cementless prostheses. MATERIAL AND METHODS We retrospectively analyzed and followed 45 patients (45 hips) who underwent THA with cementless prostheses between 2010 and 2017. There were 45 patients, including 17 men and 28 women. The average age of the patients was 46 years (range, 18-67 years). All hip infections occurred in early childhood or adolescence, and the mean interval between initial infection and THA was 38.2 years (range, 15-60 years). The mean follow-up was 6.1 years (range, 2.7-9.5 years). RESULTS Two patients underwent revision surgery because of loosening of the prosthesis, and 1 patient underwent revision surgery because of a new infection with no relationship with childhood infection during the follow-up. The average Harris hip scores significantly increased from 43.1 to 86.4 (P<0.01), and the average visual analog scale significantly increased from 4.6 to 1.7 (P<0.01). The hip dysfunction and osteoarthritis outcome scores were also significantly changed (P<0.01) at the final follow-up. There were 2 cases of transient sciatic nerve palsy and intraoperative periprosthetic fractures in 3 cases. During follow-up, single revision was performed after 6 years of primary arthroplasty because of aseptic loosening in 2 cases and prosthesis infection in 1 case, which was not related to childhood pathogens. CONCLUSIONS THA for patients with sequelae of hip joint infection has a satisfactory effect that can effectively relieve joint pain and improve hip function. The recurrence rate of infection after either pyogenic infection or tuberculous is very low. The mid-term outcomes of THA in this setting were satisfactory, with high prosthesis survivorship and hip function scores.

Background: Ankylosing spondylitis (AS) is a common infammatory rheumatic disease that affects the axial skeleton. Traditional Chinese medicine (TCM) nonpharmacological interventions are gaining an increasing popularity for AS. Nevertheless, the evidence of efficacy and safety of random controlled trials (RCTs) remains controversial. This study aims to evaluate the efficacy and acceptability of different TCM nonpharmacological therapies by systematic review and network meta-analysis., Methods: According to the strategy, the authors will retrieve a total of 7 electronic databases by December 2020, including PubMed, the Cochrane Library, EMbase, China National Knowledge Infrastructure, China Biological Medicine, Chongqing VIP, and Wan-fang databases After a series of screening, 2 researchers will use Aggregate Data Drug Information System and Stata software to analyze the data extracted from the randomized controlled trials of TCM nonpharmacological interventions for AS. The primary outcome will be the improvement of Pain intensity and functional status/disability and the secondary outcomes will include lobal improvement, health-related quality of life, satisfaction with treatment, and adverse events. Both classical meta-analysis and network meta-analysis will be implemented to investigate direct and indirect evidences on this topic. The quality of the evidence will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation instrument., Results: This study will provide a reliable evidence for the selection of TCM nonpharmacological therapies in the treatment of AS., Conclusion: This study will generate evidence for different TCM nonpharmacological therapies for AS and provide a decision-making reference for clinical research., Ethics and Dissemination: This study does not require ethical approval. The results will be disseminated through a peer-reviewed publication., Osf Registration Number: DOI 10.17605/OSF.IO/FHD2U., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Introduction: Lumbar spinal stenosis (LSS) is a common lumbar degenerative disease in the elderly, usually requiring surgery if conservative treatment fails. Microscopic decompressive laminectomy (MDL) and percutaneous endoscopic decompressive laminectomy (PEDL) have been widely used to treat LSS. This study aims to provide a protocol for the evaluation and comparison of the efficacy, safety and applicability between MDL and PEDL., Methods and Analysis: We will search for randomised controlled trials (RCTs) comparing MDL and PEDL for treating LSS from inception to December 2019 in the following databases: PubMed, The Cochrane Library, Web of Science, Embase and China Biology Medicine. The quality of included studies will be assessed using the risk of bias tool recommended by the Cochrane Handbook 5.2.0. Subsequently, a meta-analysis will be performed using RevMan 5.3 software., Ethics and Dissemination: Given the nature of this study, no ethical approval will be required. The protocol will be disseminated via a peer-reviewed journal., Prospero Registration Number: CRD42020164765., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Lumbar spinal stenosis (LSS) is a common and frequently-occurring disease in clinical practice. There are many interventions to treat it, and percutaneous endoscopic decompression (PED) is one of them, but their relative efficacy and safety remains unclear. Hence, the present study aims to synthesize the available direct and indirect evidence on the PED and other treatments for LSS., Methods: The following databases will be searched: Cochrane Library, PubMed, Web of Science, Embase and China Biomedical Literature Database (CBM). The search dates will be set from the inception to April 2019. All randomized controlled trials (RCTs) will be included in this network meta-analysis (NMA) and their risk of bias will be assessed using Cochrane handbook tool by 2 independent authors. The efficacy outcomes including: Back and Leg Visual Analog Scale (VAS) score, MacNab criteria, the Oswestry Disability Index (ODI), and Japanese Orthopedic Association (JOA) score. The safety outcomes including: incidence of complications (dura tear, incomplete decompression, reoperation, etc.). A network meta-analysis will be performed using R x64 3.5.1 software and pairwise meta-analysis will be conducted using Stata 12.0 software. Grading of recommendations assessment, development, and evaluation (GRADE) will be used to assess evidence quality., Results: The results of NMA will be submitted to a peer-reviewed journal., Conclusion: The NMA will provide a comprehensive evidence summary on treatments for patients with LSS., Protocol Registration Number: CRD42019120509.

Background/aims: This study aimed to investigate the incidence and risk factors of portal vein system thrombosis (PVST) in patients with liver cirrhosis after splenectomy and pericardial devascularization., Materials and Methods: We retrospectively analyzed 71 patients who underwent splenectomy with pericardial devascularization for portal hypertension due to cirrhosis. Patients were categorized into Group A (n=23): early prophylactic anticoagulants therapy; Group B (n=29): late prophylactic anticoagulants therapy; and Group C (n=19): no anticoagulation therapy. Univariate and multivariate analyses of the risk factors of PVST were performed. The incidence of PVST and the effect of thrombolytic therapy were evaluated., Results: Multivariate analysis revealed a wider preoperative splenic vein diameter (≥8 mm), and lower preoperative platelet counts (<50×109/L) were significantly correlated with PVST development. The incidence of PVST in Groups A, B, and C was 26.1% (6/23), 44.8% (13/29), and 52.6% (10/19), respectively (all p>0.05). The complete resolution rate of portal, superior mesenteric, and splenic vein thrombosis was 75%, 62.5%, and 23.8%, respectively., Conclusion: A wider preoperative splenic vein diameter and lower preoperative platelet counts are independent risk factors of PVST. Early anticoagulation therapy had a tendency towards a reduced incidence of PVST, but it was not statistically significant. The complete resolution rate of splenic vein thrombosis was lower than that of portal and superior mesenteric vein thrombosis.