Transmission dynamics of a reaction-advection-diffusion dengue fever model with seasonal developmental durations and intrinsic incubation periods.

In this paper, we propose a reaction-advection-diffusion dengue fever model with seasonal developmental durations and intrinsic incubation periods. Firstly, we establish the well-posedness of the model. Secondly, we define the basic reproduction number ℜ 0 for this model and show that ℜ 0 is a threshold parameter: if ℜ 0 < 1 , then the disease-free periodic solution is globally attractive; if ℜ 0 > 1 , the system is uniformly persistent. Thirdly, we study the global attractivity of the positive steady state when the spatial environment is homogeneous and the advection of mosquitoes is ignored. As an example, we use the model to investigate the dengue fever transmission case in Guangdong Province, China, and explore the impact of model parameters on ℜ 0 . Our findings indicate that ignoring seasonality may underestimate ℜ 0 . Additionally, the spatial heterogeneity of transmission may increase the risk of disease transmission, while the increase of seasonal developmental durations, intrinsic incubation periods and advection rates can all reduce the risk of disease transmission.

Consistency evaluation of exercise target heart rate determined by resting heart rate and anaerobic threshold in chronic heart failure patients.

PURPOSE: To evaluate the consistency on the target heart rate for exercise determined by simple target heart rate (sTHR) based on resting heart rate (HRrest) and heart rate at anaerobic threshold (HRAT) in cardiopulmonary exercise test (CPET) for patients with chronic heart failure. METHODS: This is a retrospective cohort study, in which CHF patients who underwent CPET in Tongji Hospital Cardiac Rehabilitation Center Affiliated to Tongji University from March 2007 to December 2018 were enrolled. The clinical data of the patients from the electronic medical record system, HRrest and HRAT measured by CPET were collected. Patients were further divided into subgroups according to gender, age (<60 years group and ≥ 60 years group), with or without beta-blocker therapy and subgroup of heart failure (heart failure with reduced, mid-range and preserved ejection fraction). The sTHR (HRrest plus 10, 15, 20, 25 and 30 bpm) and HRAT were all calculated in each patient. Paired t-test was used for the difference between the two methods, correlation analysis was shown by pearson analysis and intraclass correlation coefficient (ICC) was calculated for consistency test. RESULTS: A total of 547 CHF patients were enrolled, including 447 males (81.7%), aged 63 (56,69) years, with BMI of 25.2 (23.5,26.4) kg/m2 and LVEF of 45.0 (36.0, 52.0) %. The target heart rate determined by HRAT method was (93.59 ± 13.95) bpm, and its counterpart determined by HRrest plus 20 bpm (HRrest+20) was (93.16 ± 7.69) bpm. There was no significant difference between the two methods (P>0.05). However, it was statistically different between HRrest plus 10, 15, 25, 30 bpm and HRAT respectively (P<0.001). And HRrest+20 was positively correlated with HRAT (r = 0.418, P<0.001). Therefore, HRrest+20 below was regarded as sTHR. The ICC of the consistency test between sTHR and HRAT was 0.523,95%CI 0.435-0.596 (P < 0.001) in all patients (n = 547). In patients with beta-blocker therapy (n = 464), the ICC of sTHR and HRAT consistency test was 0.534,95%CI 0.441-0.612, P < 0.001; The ICC of the consistency test between sTHR and HRAT of patients without beta-blocker therapy (n = 83) was 0.407,95%CI 0.083-0.616, P < 0.05. In the sinus rhythm group (n = 466), the ICC of sTHR and HRAT consistency test was 0.527,95%CI 0.433-0.606, P < 0.001; The ICC of the consistency test between sTHR and HRAT of atrial fibrillation patients in group (n = 81) was 0.482,95%CI 0.195-0.667, P < 0.05.The ICC of the consistency test between sTHR and HRAT was 0.501,95%CI 0.338-0.623 (P < 0.001) in patients under 60 years old (n = 195); The ICC of the consistency test between sTHR and HRAT in patients ≥60 years old (n = 352) was 0.533,95%CI 0.424-0.621, P < 0.001. In the male group (n = 447), the ICC of sTHR and HRAT consistency test was 0.577,95%CI 0.491-0.649, P < 0.001; The ICC of the consistency test between sTHR and HRAT of female patients in group (n = 100) was 0.344,95%CI 0.025-0.559, P < 0.05. The ICC of sTHR and HRAT consistency test in HFrEF group (n = 170) was 0.395,95%CI 0.181-0.553, P < 0.01; The ICC values of the consistency test between sTHR and HRAT was 0.543, 95%CI 0.405-0.649 (P < 0.001) in patients with HFmrEF (n = 222); In HFpEF group (n = 155), the ICC of sTHR and HRAT consistency test was 0.620,95%CI 0.478-0.723, P < 0.001. CONCLUSION: The exercise target heart rate calculated by HRrest is consistent with that determined by HRAT in patients with CHF. For primary hospitals without CPET, exercise prescription equivalent to AT intensity for patients with CHF can be determined by HRrest. However, the target heart rate calculated by HRrest can't replace that determined by HRAT in this patient cohort completely.