128 research outputs found
Randomness complexity as a family feature of rolling bearings’ degradation
Randomness complexity is a kind of features which is widely used to describe bearings’ degradation. However, different randomness complexities present different properties. It is necessary to figure out different randomness complexities’ properties. In this paper, we are going to make comparisons of seven commonly used randomness complexities namely approximate entropy, sample entropy, fuzzy entropy, Shannon entropy, permutation entropy, Lempel-Ziv complexity and C0 complexity by simulation signals with three different aspects and two run-to-failure bearing’s data. By comparisons, we have found that there are a kind of similarity between them and we have proposed a trend similarity index to expound this similarity. Based on the comparisons, we can infer that randomness complexities are a family feature of rolling bearings’ degradation. Among the seven discussed complexities, sample entropy has the best performance, and it can be a good representative of the complexity features. In this paper, the difference between complexity features and other features when monitoring bearings’ degradation have been discussed. The research will provide a reference for rolling bearings’ multi-features dimensionality reduction by attribute selection method
Rolling Element Bearing Performance Degradation Assessment Using Variational Mode Decomposition and Gath-Geva Clustering Time Series Segmentation
By focusing on the issue of rolling element bearing (REB) performance degradation assessment (PDA), a solution based on variational mode decomposition (VMD) and Gath-Geva clustering time series segmentation (GGCTSS) has been proposed. VMD is a new decomposition method. Since it is different from the recursive decomposition method, for example, empirical mode decomposition (EMD), local mean decomposition (LMD), and local characteristic-scale decomposition (LCD), VMD needs a priori parameters. In this paper, we will propose a method to optimize the parameters in VMD, namely, the number of decomposition modes and moderate bandwidth constraint, based on genetic algorithm. Executing VMD with the acquired parameters, the BLIMFs are obtained. By taking the envelope of the BLIMFs, the sensitive BLIMFs are selected. And then we take the amplitude of the defect frequency (ADF) as a degradative feature. To get the performance degradation assessment, we are going to use the method called Gath-Geva clustering time series segmentation. Afterwards, the method is carried out by two pieces of run-to-failure data. The results indicate that the extracted feature could depict the process of degradation precisely
Randomness complexity as a family feature of rolling bearings’ degradation
Randomness complexity is a kind of features which is widely used to describe bearings’ degradation. However, different randomness complexities present different properties. It is necessary to figure out different randomness complexities’ properties. In this paper, we are going to make comparisons of seven commonly used randomness complexities namely approximate entropy, sample entropy, fuzzy entropy, Shannon entropy, permutation entropy, Lempel-Ziv complexity and C0 complexity by simulation signals with three different aspects and two run-to-failure bearing’s data. By comparisons, we have found that there are a kind of similarity between them and we have proposed a trend similarity index to expound this similarity. Based on the comparisons, we can infer that randomness complexities are a family feature of rolling bearings’ degradation. Among the seven discussed complexities, sample entropy has the best performance, and it can be a good representative of the complexity features. In this paper, the difference between complexity features and other features when monitoring bearings’ degradation have been discussed. The research will provide a reference for rolling bearings’ multi-features dimensionality reduction by attribute selection method
The development of clinical guidelines in China : insights from a national survey
Previous research suggests that the quality of clinical guidelines (CGs) in China is suboptimal. However, little is known about the methodology that CGs follow. We conducted a national survey of methods used by Chinese CG developers for CG development, adaptation, and updating. We used a previously piloted questionnaire based on methodologies of CG development, adaptation, and updating, which was distributed during September-November 2020 to 114 organizations identified from published Chinese CGs (searched 2017-2020), recommended by Chinese CG developers, and recommended by clinical discipline experts. We collected 48 completed questionnaires (42.1% response). Most organizations developed CGs based on scientific evidence (89.6%), existing CGs (75%), or expert experience and opinion (64.6%). Only a few organizations had a specific CG development division (6.3%), a CG monitoring plan (on clinicians 33.3%; on patients 18.8%), funding (33.3%), or a conflict-of-interest (COI) management policy (23.4%). Thirty (62.5%) organizations reported using a CG development methodology handbook, from international organizations (14/30, 46.7%), methodology or evaluation resources (3/30, 10.0%), expert experience and opinion (3/30, 10.0%), or in-house handbooks (3/30, 10.0%). One organization followed a published adaptation methodology. Thirty-eight organizations (88.4%) reported de novo CG development: 21 (55.3%) formed a CG working group, and 29 (76.3%) evaluated the quality of evidence (21 [72.4%] using a methodological tool). Nineteen organizations (52.8%) reported CG adaptation: three (31.6%) had an adaptation working group, and 12 (63.2%) evaluated the quality of source CGs (2 (16.7%) using the AGREE II instrument). Thirty-three organizations (68.8%) updated their CGs, seven (17.5%) using a formal updating process. Our study describes how CGs are developed in a middle-income country like China. To ensure better healthcare, there is still an important need for improvement in the development, adaptation, and updating of CG in China. The online version contains supplementary material available at 10.1186/s12961-021-00799-7
The gut microbiome dysbiosis and regulation by fecal microbiota transplantation: umbrella review
BackgroundGut microbiome dysbiosis has been implicated in various gastrointestinal and extra-gastrointestinal diseases, but evidence on the efficacy and safety of fecal microbiota transplantation (FMT) for therapeutic indications remains unclear.MethodsThe gutMDisorder database was used to summarize the associations between gut microbiome dysbiosis and diseases. We performed an umbrella review of published meta-analyses to determine the evidence synthesis on the efficacy and safety of FMT in treating various diseases. Our study was registered in PROSPERO (CRD42022301226).ResultsGut microbiome dysbiosis was associated with 117 gastrointestinal and extra-gastrointestinal. Colorectal cancer was associated with 92 dysbiosis. Dysbiosis involving Firmicutes (phylum) was associated with 34 diseases. We identified 62 published meta-analyses of FMT. FMT was found to be effective for 13 diseases, with a 95.56% cure rate (95% CI: 93.88–97.05%) for recurrent Chloridoids difficile infection (rCDI). Evidence was high quality for rCDI and moderate to high quality for ulcerative colitis and Crohn’s disease but low to very low quality for other diseases.ConclusionGut microbiome dysbiosis may be implicated in numerous diseases. Substantial evidence suggests FMT improves clinical outcomes for certain indications, but evidence quality varies greatly depending on the specific indication, route of administration, frequency of instillation, fecal preparation, and donor type. This variability should inform clinical, policy, and implementation decisions regarding FMT
Locating nidi for high-frequency chest wall oscillation smart therapy via acoustic imaging of lung airways as a spatial network
High-frequency chest wall oscillation (HFCWO) therapy is one of the techniques to facilitate the draining of a patient’s lung secretion in pathological situations, and smart therapy with HFCWO devices equipped with multiple actuators can be achieved via locating nidi in the lung. In this paper, through developing a novel acoustic lung spatial model and utilizing acoustic imaging simulation, a new and effective method for assessing lung function with acoustic imaging is presented, which links acoustic lung images with pathologic changes. The structural similarity between the acoustic reference image based on actual lung sound and our model acoustic image based on the airway impedance was achieved by an index of 0.8987, with 1 as the exact score. Simulation studies based on the model are used to analyze the practicality and the extreme design of the acoustic imaging system on the resolution of the located nidus. For instance, a practical system design with sensor numbers between 4 and 35 may recognize a lower resolution nidus length of 73 mm to a better resolution nidus length of 22 mm. On the other hand, an extreme system design with more than 1000 sensors can recognize greater nidus resolution at under 10 mm. Additionally, this research may be utilized to offer recommendations for acoustic imaging system design and assess the number of sensors and sensing diameter in current acoustic imaging systems. Furthermore, the geographic detection of nidus length allows for analyzing of HFCWO therapy results
An acoustic system of sound acquisition and image generation for frequent and reliable lung function assessment
Lung sounds can be translated into acoustic imaging as an alternative to standard imaging to assess lung function frequently for improved therapy efficiency. This study proposes a comprehensive acoustic lung imaging system translated from acquired lung sounds for continual and reliable lung function assessment in response to the growing clinical interest in frequent lung function assessment. The proposed system comprises subsystems, such as data acquisition, signal processing, and imaging algorithm. This study demonstrated the design and implementation of a robust lung sound acquisition and imaging system using microelectromechanical microphones that reduce external noise contamination through redesigned hardware and dynamic signal processing. Regarding lung signal acquisition, the proposed system accomplished better root mean square error (RMSE) by around 0.15 and signal-to-noise ratio (SNR) by about 7 dB compared to commercial digital stethoscopes. RMSE and SNR reflect the accuracy in capturing desired signals and robustness-to-noise contamination and are used to quantitatively compare the system data acquisition to the commercially available acoustic and electronic devices in a noisy setting. The proposed system’s sensor position is neutral when representing lung signals, with a signal power loss ratio of around 5 dB compared to 10 dB from digital stethoscopes, in terms of the sensor area sensing sensitivity power spectrum mapping. The proposed system obtains about 7%–12% of more accurate detection of the actual nidus length than digital stethoscopes through imaging translated from acquired lung signals. Additionally, the detected airway obstruction results agree closely (91%) with airway remodeling studies
Use of non-steroidal anti-inflammatory drugs and adverse outcomes during the COVID-19 pandemic: A systematic review and meta-analysis.
Background
There are concerns that the use of non-steroidal anti-inflammatory drugs (NSAIDs) may increase the risk of adverse outcomes among patients with coronavirus COVID-19. This study aimed to synthesize the evidence on associations between the use of NSAIDs and adverse outcomes.
Methods
A systematic search of WHO COVID-19 Database, Medline, the Cochrane Library, Web of Science, Embase, China Biology Medicine disc, China National Knowledge Infrastructure, and Wanfang Database for all articles published from January 1, 2020, to November 7, 2021, as well as a supplementary search of Google Scholar. We included all comparative studies that enrolled patients who took NSAIDs during the COVID-19 pandemic. Data extraction and quality assessment of methodology of included studies were completed by two reviewers independently. We conducted a meta-analysis on the main adverse outcomes, as well as selected subgroup analyses stratified by the type of NSAID and population (both positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or not).
Findings
Forty comparative studies evaluating 4,867,795 adult cases were identified. Twenty-eight (70%) of the included studies enrolled patients positive to SARS-CoV-2 tests. The use of NSAIDs did not reduce mortality outcomes among people with COVID-19 (number of studies [N]Â =Â 29, odds ratio [OR]Â =Â 0.93, 95% confidence interval [CI]: 0.75 to 1.14, I2 Â =Â 89%). Results suggested that the use of NSAIDs was not significantly associated with higher risk of SARS-CoV-2 infection in patients with or without COVID-19 (NÂ =Â 10, ORÂ =Â 0.96, 95% CI: 0.86 to 1.07, I2 Â =Â 78%; NÂ =Â 8, aORÂ =Â 1.01, 95% CI: 0.94 to 1.09, I2 Â =Â 26%), or an increased probability of intensive care unit (ICU) admission (NÂ =Â 12, ORÂ =Â 1.28, 95% CI: 0.94 to 1.75, I2 Â =Â 82% ; NÂ =Â 4, aORÂ =Â 0.89, 95% CI: 0.65 to 1.22, I2 Â =Â 60%), requiring mechanical ventilation (NÂ =Â 11, ORÂ =Â 1.11, 95% CI: 0.79 to 1.54, I2 Â =Â 63%; NÂ =Â 5, aORÂ =Â 0.80, 95% CI: 0.52 to 1.24, I2 Â =Â 66%), or administration of supplemental oxygen (NÂ =Â 5, ORÂ =Â 0.80, 95% CI: 0.52 to 1.24, I2 Â =Â 63%; NÂ =Â 2, aORÂ =Â 1.00, 95% CI: 0.89 to 1.12, I2 Â =Â 0%). The subgroup analysis revealed that, compared with patients not using any NSAIDs, the use of ibuprofen (NÂ =Â 5, ORÂ =Â 1.09, 95% CI: 0.50 to 2.39; NÂ =Â 4, aORÂ =Â 0.95, 95% CI: 0.78 to 1.16) and COX-2 inhibitor (NÂ =Â 4, ORÂ =Â 0.62, 95% CI: 0.35 to 1.11; NÂ =Â 2, aORÂ =Â 0.73, 95% CI: 0.45 to 1.18) were not associated with an increased risk of death.
Interpretation
Data suggests that NSAIDs such as ibuprofen, aspirin and COX-2 inhibitor, can be used safely among patients positive to SARS-CoV-2. However, for some of the analyses the number of studies were limited and the quality of evidence was overall low, therefore more research is needed to corroborate these findings.
Funding
There was no funding source for this study
Assessment of the Quality of Reporting in Abstracts of Randomized Controlled Trials Published in Five Leading Chinese Medical Journals
BACKGROUND: Clear, transparent and sufficiently detailed abstracts of randomized trials (RCTs), published in journal articles are important because readers will often base their initial assessment of a trial on such information. However, little is known about the quality of reporting in abstracts of RCTs published in medical journals in China. METHODS: We identified RCTs abstracts from 5 five leading Chinese medical journals published between 1998 and 2007 and indexed in MEDLINE. We assessed the quality of reporting of these abstracts based on the Consolidated Standards of Reporting Trials (CONSORT) abstract checklist. We also sought to identify whether any differences exist in reporting between the Chinese and English language version of the same abstract. RESULTS: We identified 332 RCT abstracts eligible for examination. Overall, the abstracts we examined reported 0-8 items as designated in the CONSORT checklist. On average, three items were reported per abstract. Details of the interventions (288/332; 87%), the number of participants randomized (216/332; 65%) and study objectives (109/332; 33%) were the top three items reported. Only two RCT abstracts reported details of trial registration, no abstracts reported the method of allocation concealment and only one mentioned specifically who was blinded. In terms of the proportion of RCT abstracts fulfilling a criterion, the absolute difference (percentage points) between the Chinese and English abstracts was 10% (ranging from 0 to 25%) on average, per item. CONCLUSIONS: The quality of reporting in abstracts of RCTs published in Chinese medical journals needs to be improved. We hope that the introduction and endorsement of the CONSORT for Abstracts guidelines by journals reporting RCTs will lead to improvements in the quality of reporting
Quantitative trait loci identification, fine mapping and gene expression profiling for ovicidal response to whitebacked planthopper (Sogatella furcifera Horvath) in rice (Oryza sativa L.)
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