Purpose This paper aims to improve the meshing effect of the gear teeth. It is recommended to analyze the deformation difference between the inner and outer surfaces of the flexspline. The purpose of this paper is to modify the profile of the flexspline based on the deformation difference to improve the transmission accuracy and operating life of the harmonic drive. Design/methodology/approach In this paper, ring theory is used to calculate the deformation difference of the inner and outer surfaces of the flexspline, and the actual tooth profile of the flexspline is corrected based on the deformation difference. Then, the flexspline is divided into multiple sections along the axial direction, so that the three-dimensional tooth profile of the flexspline is modified to improve the gear tooth meshing effect. Findings This paper proves the effect of the deformation difference between the inner and outer surfaces of the flexspline on the tooth backlash, which affects the transmission accuracy and life of the harmonic drive. It is recommended to modify the tooth profile of the flexspline based on the deformation difference, so as to ensure the tooth meshing effect. Originality/value This paper provides a new way for the optimization of the three-dimensional tooth profile design of the harmonic drive.
Introduction Apathy is a prevalent mood disturbance that occurs in a wide range of populations, including those with normal cognitive aging, mental disorders, neurodegenerative disorders and traumatic brain injuries. Recently, neuroimaging technologies have been employed to elucidate the neural substrates underlying brain disorders accompanying apathy. However, the consistent neural correlates of apathy across normal aging and brain disorders are still unclear. Methods This paper first provides a brief review of the neural mechanism of apathy in healthy elderly individuals, those with mental disorders, neurodegenerative disorders, and traumatic brain injuries. Further, following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, the structural and functional neuroimaging meta-analysis using activation likelihood estimation method is performed on the apathy group with brain disorders and the healthy elderly, aiming at exploring the neural correlates of apathy. Results The structural neuroimaging meta-analysis showed that gray matter atrophy is associated with apathy in the bilateral precentral gyrus (BA 13/6), bilateral insula (BA 47), bilateral medial frontal gyrus (BA 11), bilateral inferior frontal gyrus, left caudate (putamen) and right anterior cingulate, while the functional neuroimaging meta-analysis suggested that the functional connectivity in putamen and lateral globus pallidus is correlated with apathy. Discussion Through the neuroimaging meta-analysis, this study has identified the potential neural locations of apathy in terms of brain structure and function, which may offer valuable pathophysiological insights for developing more effective therapeutic interventions for affected patients.
Objective To compare sleep electroencephalogram-modulated repetitive transcranial magnetic stimulation (SEM-rTMS) with routine repetitive transcranial magnetic stimulation (R-rTMS) in the treatment of primary insomnia. Methods One hundred and twenty six patients with insomnia were divided randomly into a SEM-rTMS group (44 cases) , a R-rTMS group (42 cases) and a sham rTMS group (40 cases). Each case was treated with rTMS for 30 min once a day for 10 d under double blinding of the patient and therapist. The clinical effect was observed along with Krakow sleep scores, electroencephalograms and blood pressure before and after a 10-day course of therapy and 30 days later. Results During rTMS treatment, some patients reported feeling sleepy, and this was confirmed by their EEGs at the time. After the entire course of therapy, 80% of the SEM-rTMS group and 45% of the R-rTMS group showed improvements, a significant difference. At the 30th day after therapy, the effect in the SEM-rTMS group was still significantly better than in the R-rTMS group. There were no obvious side effects in any group throughout the whole observation period. Conclusions SEM-rTMS is more effective and more reliable than R-rTMS. SEM-rTMS is safe to use with primary insomnia patients.
Key words:
Transcranial magnetic stimulation; Insomnia
Although evidence-based practice provides the best diagnosis and treatment decisions for patients, there is no relevant theoretical basis for designing an evidence-based practice curriculum for medical students. Also, no study has been conducted to investigate the attitude and behaviour of evidence-based practice among resident doctors in China. Therefore, this study aims to identify the beliefs and implementation of evidence-based practice among registered resident doctors in Lianyungang First People's Hospital. A descriptive cross-sectional design was used to recruit 257 participants conveniently. Beliefs about the evidence-based practice was evaluated using the Evidence-Based Practice Beliefs scale. In addition, the implementation of Evidence-Based Practice was evaluated using the Evidence-Based Practice Implementation scale. Participants' rate of evidence-based practice was 71.60%. Cronbach's alpha was more than 0.90 for each scale. Participants who had learned about evidence-based medicine gave significantly higher scores on the Evidence-Based Practice Beliefs scale and Evidence-Based Practice Implementation scale than those who did not. This study demonstrates that resident doctors develop a positive attitude towards evidence-based practice but exercise it to a lesser extent. Integrating the theory course of evidence-based medicine at the undergraduate level with the practice course at the standardized training stage is crucial to improving their practice, aiming to enhance that patients receive the best available care based on high-quality evidence.
The optimal range of blood pressure levels in the early phase of ischemic stroke with hypertension is still controversial. Based on our stroke registry database, we explored the relationship between blood pressure levels and cerebral perfusion in the early phase of ischemic stroke with hypertension and neurofunctional recovery at 3 months after stroke. Total 732 stroke patients with hypertension were finally analyzed. Patients were divided into quintiles according to systolic blood pressure (SBP) and diastolic blood pressure (DBP) to perform multivariable logistic regression to analyze their relation with neurofunctional recovery, respectively. The cerebral perfusion levels displayed a reverse "U" shape curve with the change of blood pressure levels. Sufficient estimated cerebral blood flow (ECBF) in the early phase of ischemic stroke was associated with good neurofunctional recovery at 3 months after stroke. The best neurofunctional recovery was observed in the middle quintiles with SBP at 161 to 177 mm Hg and DBP at 103 to 114 mm Hg, respectively. So maintaining appropriate blood pressure levels in the early phase of ischemic stroke might be beneficial to cerebral perfusion and neurofunctional recovery.
Background: Evidence suggests that patients with higher blood pressure variability (BPV) have a higher risk for stroke but the relationship between BPV and stroke outcomes is unknown in those who underwent intravenous thrombolysis (IVT) for acute ischemic stroke (AIS). The objective of this study is to investigate the association among BPV, BP values and stroke outcomes. Methods: A retrospective analysis of about 510 consecutive thrombolysis cases for AIS from January 2015 to March 2019 in a single-center database were done. Then, these patients were followed-up for 3 months. We used univariate and multivariable models to evaluate the relationship between mean BP values, BPV and the risk of stroke outcomes from prior IVT to 72 h after IVT. Meanwhile, we also used COX regression to assess the hazard ratios of stroke outcomes with BPV within 3 months. Furthermore, we tested the effect of BP level at various time-points (prior to IVT and at 0, 2, 4, 8, 12, 24, 48 and 72 h after IVT) on development of postthrombolytic stroke outcomes. Results: Higher BPV from prior IVT to 72 h after IVT was associated with higher risk of stroke outcomes within 3 months [SBPV of recurrent stroke: odds ratios (OR) = 5.298, 95% confidence interval (CI) 1.339–10.968, P = 0.018; DBPV of recurrent stroke: OR = 6.397, 95% CI 1.576–25.958, P = 0.009, respectively]. In addition, patients with recurrent stroke had significantly higher mean SBP (OR=1.037, 95% CI 1.006–1.069, P = 0.019). Furthermore, higher BP at different time points were associated with greater risk of recurrent stroke from prior IVT to 72 h after IVT. Conclusion: Higher BPV and SBP from prior IVT to 72 h after IVT was associated with higher risk of stroke outcomes within 3 months.
The aim of this study was to investigate the relation between mid-term blood pressure (BP) variability (BPV) within 7 days of onset and the prognosis in acute stroke patients. Total 873 acute ischemic stroke patients were included in this study. Mid-term BPV was evaluated through the calculations of coefficient of variation (CV) of the systolic BP (SBP) and diastolic BP (DBP) within 7 days of onset. Clinical outcomes were assessed using the recovery situations of neurological function at 3 months, the primary outcome (symptomatic recurrent stroke) and the secondary outcomes (recurrent stroke, all-cause mortality, and the composite of cardiovascular events) within 12 months. Among 873 patients with ischemic stroke, 83 died, 125 developed recurrent stroke, and 212 developed cardiovascular events during 12 months' follow-up. At 3 months, systolic or diastolic BPV (within 7 days of onset) was associated with the recovery situations of neurological function in three models (all P < 0.05). Both higher CV of SBP and CV of DBP were significantly correlated with the increased risk of recurrent stroke (hazard ratio [HR] = 2.32, 95% confidence interval [CI]: 1.29–4.18, P = 0.005 for CV of SBP; HR = 2.33, 95% CI: 1.29–4.19, P = 0.005 for CV of DBP) and composite cardiovascular events (HR = 2.22, 95% CI: 1.41–3.48, P = 0.001 for CV of SBP; HR = 2.21, 95% CI: 1.41–3.47, P = 0.001 for CV of DBP) during 12 months' follow-up. After acute ischemic stroke, high systolic or diastolic BPV within 7 days of onset was associated with the recovery situations of neurological function at 3 months, and recurrent stroke and composite cardiovascular events within 12 months. URL: http://www.chictr.org.cn. Unique identifier: ChiCTR-TRC-14004804.
Objective The aim of this study was to investigate the relationship between blood pressure variability (BPV) and post stroke cognitive impairment (PSCI). Methods Seven-hundred and ninety-six patients with acute ischemic stroke were included in this study. Mid-term BPV was evaluated by calculating the standard deviation (SD) and coefficient of variation (CV, 100 × SD/mean) of systolic blood pressure (SBP) and diastolic blood pressure during the 7 days after stroke onset. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) at admission and at all follow-up visits. Patients with MoCA scores <26 were considered to have PSCI. Results The incidence of PSCI reached its peak (72%) 3 months after stroke onset and decreased to 30.3% at 12 months post-stroke. After adjusting for covariables, the increase in the prevalence of PSCI at 3 months was independently associated with increases in the coefficient of variation of blood pressure during the 7 days after stroke ( odds ratios and 95%CI for patients in the second to fifth quintiles of SBP CV were 2.28(1.18,4.39), 2.33(1.18,4.62), 2.69(1.31,5.53), 4.76(1.95,11.67), respectively ). Sub-analysis of the MoCA scores revealed that the patients had impairments in visuoperceptual abilities and executive functions, as well as in naming and delayed recall (p < 0.05). Conclusions Mid-term blood pressure variability during the early phase of acute ischemic stroke is independently associated with post-stroke cognitive impairment, especially in the visuoperceptual, executive, and delayed recall domains.
The relationship between red blood cell distribution width (RDW) in peripheral thrombolysis period and prognosis is not fully clarified in those who underwent intravenous thrombolysis (IVT) for acute ischemic stroke (AIS). Our study aimed to clarify this issue. A retrospective analysis of about 510 consecutive thrombolysis cases for AIS from January 2015 to March 2019 in a single-center database was done and followed-up for 3 months. We used univariate and multivariable models to evaluate the relationship between RDW levels at various time-points after IVT and the occurrence risk of hemorrhagic transformation (HT) and recurrent stroke, and used COX regression to assess the hazard ratios of outcomes with RDW levels. Elevated risk of HT was found in higher tertiles of RDW (OR = 10.282, 95% confidence interval (CI) 2.841â39.209, P < 0.001 in Tp tertile G3; OR = 5.650, 95% CI 1.992â16.025, P = 0.001 in T24 tertile G3; OR = 4.308, 95% CI 1.480â12.542, P = 0.007 in T48 tertile G3 and OR = 6.384, 95% CI 2.201â18.515, P = 0.001 in T72 tertile G3, respectively). Occurrence of recurrent stroke was highest in the RDW tertile G3 (HR = 4.580, 95% CI 2.123â9.883, P < 0.001 in Tp tertile G3; HR = 5.731, 95% CI 2.498â13.151, P = 0.001 in T24 tertile G3; HR = 3.019, 95% CI 1.969â4.059, P = 0.031 in T48 tertile G3; HR = 3.318, 95% CI 1.598â6.890, P = 0.001 in T72 tertile G3, respectively). Mean RDW levels â¥13.60 among AIS patients undergoing thrombolysis was associated with higher risk of HT and recurrent stroke.
Background and Purpose— Blood pressure (BP) control in the early phase of stroke is controversial to reduce the risk of poststroke cognitive impairment (PSCI). This study was to investigate the impact of BP levels in the early phase of ischemic stroke and stroke subtype on PSCI. Methods— Seven hundred and ninety-six patients with acute ischemic stroke were included. Cognitive function was assessed after stroke onset using the Montreal Cognitive Assessment. Patients were divided into quintiles according to systolic BP and diastolic BP levels in the early phase. Subtype analyses were according to Trial of ORG 10172 in Acute Stroke Treatment classification (infarct cause) and Oxfordshire Community Stroke Project classification (infarct location). Results— After adjusting for multiple variables, the quintiles with the lowest systolic BP (Q1, 102–127 mm Hg) and with the highest systolic BP (Q5, 171–215 mm Hg) were associated with increased PSCI risk (odds ratio, 1.83; 95% confidence interval, 1.64–2.28; P =0.007 in Q1; odds ratio, 2.32; 95% confidence interval, 1.74–2.90; P <0.001 in Q5) at 3 months as compared with the middle quintile (Q3, 143–158 mm Hg). Similar association was found in diastolic BP quintiles. The analysis of cerebral infarction subtype demonstrated that both large artery atherosclerosis and total anterior circulation infarct were associated with increased risk of PSCI at 3 months after adjusting for multiple variables (large artery atherosclerosis: odds ratio, 1.42; 95% confidence interval, 1.06–1.90; P =0.031; total anterior circulation infarct: odds ratio, 1.68; 95% confidence interval, 1.32–2.15; P =0.001). Conclusions— Lower or higher BP in the early phase of ischemic stroke was correlated with increased PSCI risk at 3 months. Maintaining systolic/diastolic BP in the levels of 143 to 158/93 to 102 mm Hg might be beneficial to reduce the occurrence of PSCI. Moreover, large artery atherosclerosis subtype and total anterior circulation infarct subtype were correlated with increased PSCI risk at 3 months. Clinical Trial Registration— URL: https://www.chictr.org . Unique identifier: ChiCTR-TRC-14004804.
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