A nonlinear ultrasonic wave mixing method for looseness detection of bolted joints.

Bolted joints are widely used in various machines and engineering structures. The tightening state of bolts directly affects the reliability and safety of bolted joints. Therefore, the bolt looseness detection is very important to ensure the reliability of bolted joints. In this paper, a novel nonlinear ultrasonic wave mixing method is proposed for looseness detection of bolted joints. The basic theory of the nonlinear ultrasonic wave mixing method for detecting the bolt looseness is established. Based on the detection theory, a nonlinear modulation index is defined to quantify the level of bolt looseness. An experimental setup is built to implement the nonlinear ultrasonic wave mixing detection method on bolted joints. Experiments are conducted on two bolted joints with different materials and sizes. The influences of excitation frequencies and voltages of two ultrasonic signals on the detection performance are investigated experimentally. A method is proposed for the selection of appropriate excitation frequencies to improve the detection performance. The experimental results demonstrate that the proposed method can effectively detect bolt looseness and it has good detection sensitivity to the early bolt loosening.

A systematic review on reporting quality of economic evaluations for negotiated glucose-lowering drugs in China national reimbursement drug list.

BACKGROUND: This study aimed to examine the reporting quality of existing economic evaluations for negotiated glucose-lowering drugs (GLDs) included in China National Reimbursement Drug List (NRDL) using the Consolidated Health Economic Evaluation Reporting Standards 2013 (CHEERS 2013). METHODS: We performed a systematic literature research through 7 databases to identify published economic evaluations for GLDs included in the China NRDL up to March 2021. Reporting quality of identified studies was assessed by two independent reviewers based on the CHEERS checklist. The Kruskal-Wallis test and Mann-Whitney U test were performed to examine the association between reporting quality and characteristics of the identified studies. RESULTS: We have identified 24 studies, which evaluated six GLDs types. The average score rate of the included studies was 77.41% (SD:13.23%, Range 47.62%-91.67%). Among all the required reporting items, characterizing heterogeneity (score rate = 4.17%) was the least satisfied item. Among six parts of CHEERS, results part scored least at 0.55 (score rate = 54.79%) because of the incompleteness of characterizing uncertainty. Results from the Kruskal-Wallis test and Mann-Whitney U test showed that model choice, journal type, type of economic evaluations, and study perspective were associated with the reporting quality of the studies. CONCLUSIONS: There remains room to improve the reporting quality of economic evaluations for GLDs in NRDL. Checklists such as CHEERS should be widely used to improve the reporting quality of economic researches in China.

Patient preferences and shared decision making for the traditional Chinese medicine treatment of lung cancer: A discrete choice experiment study.

Background: Traditional Chinese Medicine (TCM), integrating patient preferences into decision-making process, has been widely used in the multimodality therapy of lung cancer. This study aimed to estimate patient preferences for treatment and shared decision-making (SDM) modes concerning inpatient TCM treatment of lung cancer in Shanghai in order to provide a basis for clinical decision-making process on TCM therapy for lung cancer. Methods: This study was conducted among patients (n = 347) from nine tertiary hospitals in Shanghai by discrete-choice experiment (DCE) survey and Shared Decision-Making Questionnaire-patient version (SDM-Q-9) survey. The DCE was developed with the inclusion of the most relevant attributes at appropriate levels for the TCM treatment of lung cancer. The empirical data analyses of patients were performed using mixed logit models. Additionally, subgroup analysis was conducted. Results: In total, 347 respondents completed the questionnaire. All attributes' coefficients were statistically significant for patients' preferences. Patients showed strong preferences for increasing disease control rate, relieving nausea and vomiting, reducing the risk of side effects, and were concerned about monthly out-of-pocket costs. Subgroup analysis indicated that patients with a lower SDM-Q-9 score and those who were satisfied with medical services emphasized more importance of higher disease control rate. Furthermore, most of the patients (90.20%) self-reported a high willingness to use SDM during the decision-making process. Conclusion: In Shanghai, patients mainly preferred SDM and considered disease control rate as the most essential attribute in the TCM treatment of lung cancer. The study findings could underscore the importance of considering patients' preferences and promote SDM.

Thermo-Hydrodynamic Lubricating Behaviors of Upstream Liquid Face Seals with Ellipse Dimples.

In order to obtain the leakage characteristics of an upstream pumping face seal with inclined ellipse dimples under high-temperature and high-speed liquid lubricating conditions, a thermo-hydrodynamic lubricating model is developed. The novelty of this model is that it takes the thermo-viscosity effect and cavitation effect into account. The influence of operating parameters, such as rotational speed, seal clearance, seal pressure, ambient temperature and structural parameters, such as dimple depth, inclination angle, slender ratio and dimple number on the opening force and leakage rate, is numerically calculated. The results obtained show that the thermo-viscosity effect makes the cavitation intensity decrease noticeably, leading to an increase in the upstream pumping effect of ellipse dimples. Moreover, the thermo-viscosity effect may make both the upstream pumping leakage rate and opening force increase by about 10%. It can also be found that the inclined ellipse dimples can produce an obvious upstream pumping effect and hydrodynamic effect. Based on the reasonable design of the dimple parameter, not only can the sealed medium achieve zero leakage, but the opening force can also increase by more than 50%. The proposed model has the potential to provide the theoretical basis for and guide the future designs of upstreaming liquid face seals.

Patient preferences for anti-hyperglycaemic medication for type 2 diabetes mellitus in China: findings from a national survey.

OBJECTIVE: This study aimed to investigate the preferences regarding risks, benefits and other treatment attributes of patients with type 2 diabetes mellitus (T2DM) in China when selecting a second-line anti-hyperglycaemic medicine. METHODS: A discrete choice experiment with hypothetical anti-hyperglycaemic medication profiles was performed using a face-to-face survey administered to patients with T2DM. The medication profile was described using seven attributes: treatment efficacy, hypoglycaemia risk, cardiovascular benefits, gastrointestinal (GI) adverse events, weight change, mode of administration and out-of-pocket cost. Participants chose between medication profiles by comparing attributes. Data were analysed using a mixed logit model with marginal willingness to pay (mWTP) and maximum acceptable risk (MAR) calculated. The preference heterogeneity within the sample was explored using a latent class model (LCM). RESULTS: A total of 3327 respondents from five major geographical regions completed the survey. Treatment efficacy, hypoglycaemia risk, cardiovascular benefits and GI adverse events were major concerns among the seven attributes measured. Weight change and mode of administration were of lesser concern. Regarding mWTP, respondents would pay ¥236.1 (US$36.6) for an anti-hyperglycaemic medication with an efficacy of 2.5% points reduction in HbA1c, while they were willing to accept a weight gain of 3 kg only if they received a compensation of ¥56.7 (US$8.8). Respondents were willing to accept a relatively large increase in hypoglycaemia risk (MAR=15.9%) to improve treatment efficacy from intermediate (1.0% points) to high (1.5% points). LCM identified the following four unobserved subgroups: trypanophobia, cardiovascular-benefits-focused, safety-focused and efficacy-focused and cost-sensitive. CONCLUSION: Patients with T2DM prioritised free out-of-pocket costs, highest efficacy, no hypoglycaemia risk and cardiovascular benefits over weight change and mode of administration. There exists great preference heterogeneity among patients, which should be taken into account in healthcare decision-making processes.

Thermo-Hydrodynamic Effect of Gas Split Floating Ring Seal with Rayleigh Step Grooves.

The force equilibrium and moment equilibrium play a significant role on the sealing performance of gas split floating ring seals. A small deflection angle may generate seriously wear on sealing surface and cause seal failure. Therefore, the thermo-hydrodynamic lubrication analysis of gas split floating ring seal with Rayleigh grooves is investigated considering the deflection angle and frictional heat of surface contact, which is beneficial to grasp the hydrodynamic characteristics and rules under high-temperature and high-speed conditions. Pressure and temperature distributions of sealing rings are numerically calculated for the cases with different deflection angle, rational speed, seal pressure and ambient temperature. Then, the hydrodynamic effect and sealing performance are analyzed. The obtained results show that, the surface Rayleigh step grooves do not present obvious hydrodynamic effect when split seal ring has no deflection. While, a significant hydrodynamic effect can be obtained when the split seal ring presents a deflection angle about dozens of micro radians. Here, a 10% increase of opening force is achieved when the deflection angle reaches 80 µrad in the case of speed 30,000 r/min and seal pressure 0.2 MPa. Moreover, the hydrodynamic effect becomes obvious with increasing deflection angle as well as rotational speed. Meanwhile, the growth of rotational speed results in an obvious increase of film temperature. The increase of ambient temperature has a significant influence on the decrease of leakage rate. When the ambient temperature increases from 340 K to 540 K, the leakage rate reduces exceeding 50%, however, it does not present obvious effect on the opening force. The proposed model has the potential to provide the theoretical basis and design guidance for surface grooves of gas split floating ring seal in the future.

Reporting quality of economic evaluations of the negotiated Traditional Chinese Medicines in national reimbursement drug list of China: A systematic review.

Background: Traditional Medicine (TM) has a wide uptake in most countries. In China, Traditional Chinese Medicine (TCM) is a common kind of primary health because of its beneficial effects. This review aimed to appraise the publication reporting quality of economic evaluations for selective TCM in the National Reimbursement Drug List (NRDL), Version 2020, based on the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement. Methods: Electronic databases were searched for economic evaluation that supported the TCM negotiations in NRDL (2020 version) published from 2001 to 2021, including PubMed, Web of Science, Embase, CNKI, WanFang, and SinoMed. The CHEERS statement was used to appraise the reporting quality of included TCM economic evaluations. Results: A total of 360 articles were retrieved, but only 38 economic evaluations met the inclusion criteria. None of the articles reported all items in the CHEERS checklist. The mean score of included articles is low at 10.93±2.62, with an average scoring rate of 51.31±10.53%. The least reported items included: "Characterizing heterogeneity," "Conflicts of interest", "Discount rate," and "Study perspective," with a reporting rate of 0.00%, 5.26%, 7.89%, and 15.79%, respectively. Conclusion: An upward trend occurred in the quantity and quality of the economic evaluation publications of TCM in China. TCM economic evaluations are still at an early stage, with an urgent need for improving reporting quality. It may result from research experiences or different ideas between TCM and Western Medicine. Adhering to reporting guidelines like CHEERS and educating economic evaluation investigators can improve TCM economic evaluations' reporting quality.

Physician Preferences and Shared-Decision Making for the Traditional Chinese Medicine Treatment of Lung Cancer: A Discrete-Choice Experiment Study in China.

Background: With progress being made in the treatment of cancer, various clinical and treatment options are being pursued. In China, Traditional Chinese Medicine (TCM) is used widely in the treatment of cancer. Objective: To estimate TCM treatment preferences and SDM mode of physicians in China. Methods: This study was conducted among physicians (n=185) from nine tertiary hospitals in China by discrete-choice experiment (DCE) survey and Shared Decision-Making Questionnaire-physician version (SDM-Q-Doc) survey. The DCE was developed with the inclusion of the most relevant attributes at appropriate levels for the TCM treatment of lung cancer. The empirical data analyses of physicians were performed using mixed logit models. Additionally, subgroup analysis was conducted. Results: In total, 185 respondents completed the questionnaire. All attributes were statistically significant except out-of-pocket costs. Physicians showed the strongest preferences for increasing disease control rate, relieving nausea and vomiting, and reducing the risk of side effects. Most of the physicians (78.38%) self-reported a high willingness to use SDM during the decision-making process. The physicians with a higher SDM-Q-Doc score had more preference for improving all three attributes than those with a lower score. Little variation was found in preferences among the physicians with other sociodemographic characteristics. Conclusion: In China, physicians considered disease control rate as the most essential attribute in the TCM treatment of lung cancer. The physicians in China mainly preferred SDM, and the preference was different according to SDM mode when involving the TCM therapy for patients with lung cancer. The study findings could inform future TCM therapy for lung cancer and promote SDM.