Finite-time relative pose tracking control for uncertain spacecraft rendezvous and docking

This study investigates the robust finite-time pose tracking control for spacecraft autonomous rendezvous and docking with parametric uncertainties and bounded external disturbances. Based on the uncertainly coupled relative pose dynamics, a fast terminal sliding mode controller is developed to achieve the finite-time convergence of the pose tracking errors. To reduce the control chattering results from the signum function in the controller, an exponential reaching law is employed to achieve the decreasing of the reaching time towards the sliding surface. The explicit tuning rules for designing parameters are derived based on the stability analysis of the closed-loop system. It is proved in Lyapunov framework that all closed-loop signals are always kept bounded and the pose tracking error converges to small neighborhood of zero in finite time. Simulation results validate the performance of the proposed robust finite-time control strategy

Table_1_Seasonal variation in the detection rate and all-cause in-hospital mortality of AKI in China: A nationwide cohort study.pdf

BackgroundAcute kidney injury (AKI) is a severe clinical syndrome that places a massive burden on medical systems worldwide, yet the seasonality of AKI remains unexplored in China. The aim of this study was to describe the seasonal variation in the detection rate and all-cause in-hospital mortality of AKI in China based on a nationwide cohort study.MethodsThis was a retrospective cohort recruiting a national sample of 7,291 adult patients treated in hospitals in 22 provinces of mainland China during January or July 2013. AKI was defined according to the 2012 Kidney Disease Improving Global Outcomes AKI creatinine criteria or expanded criteria of increase or decrease in serum creatinine level of 50% during the hospital stay. The seasonal group was determined according to the corresponding admission date for each patient. The detection rate of AKI refers to the ratio of identified AKI cases to the total number of adult admissions from the same regional or seasonal group.ResultsBoth the detection rate (2.31 vs. 2.08%, p = 0.001) and in-hospital mortality rate (13.3 vs. 10.7%, p = 0.001) of AKI were higher in winter than in summer. The patients with AKI detected in winter had higher proportions of prehistory diseases, cardiac or vascular kidney injury factors, and severe comorbidities than those in summer (all p ConclusionThe detection rate and all-cause in-hospital mortality of AKI showed a winter predominance in patients with AKI in China. Winter appeared to be an independent risk factor for all-cause in-hospital mortality in patients with AKI. Environmental factors, including lower ambient temperature, higher relative humidity level, and living in temperate continental climatic regions, were each independently associated with increased risks of in-hospital mortality in patients with AKI.</p

Additional file 1: Table S1. of Reduced Kidney Function, Albuminuria, and Risks for All-cause and Cardiovascular Mortality in China: A Population-based Cohort Study

and S2.Hazard ratios for all-cause and cardiovascular mortality by indicators of chronic kidney disease among participants aged less than 65 years old, as well as among those aged more than 65 years old. (DOCX 17 kb

Metabolic Syndrome without Diabetes or Hypertension Still Necessitates Early Screening for Chronic Kidney Disease: Information from a Chinese National Cross-Sectional Study

<div><p>Metabolic syndrome (MS) is prevalent, with an increasing contribution to the incidence of chronic kidney disease (CKD). The study of the relationship between them is important. The CKD survey, a national cross-sectional study, provided a large database to accomplish this study. The study population were 41 131 adults from this survey between 2008 and 2009. CKD was defined as estimate glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m² or the presence of albuminuria. MS was diagnosed by National Cholesterol Education Program—Adult Treatment Panel III (ATPIII), ATPIII-modified or International Diabetes Federation (IDF) criteria. Logistic regression model was applied to study the impact of MS or its components on CKD or its components. The age and sex standardized prevalence of MS by ATPIII, ATPIII-modified and IDF criteria was 11.77% (11.13%–12.40%), 21.51% (20.69%–22.34%) and 16.67% (15.92–17.42)% respectively. Multivariate logistic regression models showed that MS and its components were associated with higher CKD prevalence. The risk for CKD and its components increased with the number of MS components. After adjusting for hypertension and diabetes, the odds ratios of MS for CKD decreased, but remained significantly more than 1 between 1.16(95%CI 1.07–1.26) and 1.37 (95% CI 1.25–1.50) across the different models. Similar results were found with albuminuria, while for decreased eGFR, after adjusting for hypertension and diabetes, the odds ratios of MS and MS components (except elevated TG) became insignificant. In conclusion, MS is prevalent and associated with a higher prevalence of CKD. Different MS components are associated with different risks for CKD, even after adjusting for hypertension and diabetes, which may mainly be contributed more by the increased risk for albuminuria than that for decreased eGFR. More attention must be paid to the population with MS, including those with elevated blood pressure and serum glucose.</p></div

Association between metabolic syndrome and albuminuria.

<p><i>Note</i>: OR1: adjustment for age, sex, hypertension and diabetes. OR2: OR1 plus adjustment for cardiovascular disease; OR3: OR2 plus adjustment for former kidney disease and nephrotoxic drugs. OR4: OR3 plus adjustment for hyperuricaemia. OR5: OR4 plus adjustment for smoking, alcohol, regular exercise, and income.</p><p>Central OB1: obesity according to WC by ATP-III; Central OB2: obesity according to WC by ATP-III modified or IDF; Obesity (BMI): > = 25Kg/m², only obesity by IDF or ATP-III modified criteria was used to calculate MS components.</p><p>Association between metabolic syndrome and albuminuria.</p

OR for CKD by different compositions of MS components compared to participants without any of MS components.

<p>OR was calculated by logistic regressions adjusted for age and gender, obesity according to IDF or ATP-III was used in the analysis. <i>y</i>-axis represent OR for CKD, <i>x</i>-axis represent the compositions of MS components. ‘+’ indicated presence of the component at the same line and ‘-’ indicated absence of component at the same line. Different colors of vertical bars represent different numbers of MS components.</p

Classification performance of the single metrics and multi-modal combinations.

<p>Classification performance of the single metrics and multi-modal combinations.</p

Regions of interest (ROIs) included in the AAL-atlas.

<p>Regions of interest (ROIs) included in the AAL-atlas.</p

The number of features retained in the multi-model method per fold.

<p>The number of features retained in the multi-model method per fold.</p

Classification performance of the multi-model method.

<p>The ROC curve of the classifier. The area under the ROC curve was 0.951.</p