Quantifying the effects of stripe rust disease on wheat canopy spectrum based on eliminating non-physiological stresses

The wheat canopy reflectance spectrum is affected by many internal and external factors such as diseases and growth stage. Separating the effects of disease stress on the crop from the observed mixed signals is crucial for increasing the precision of remote sensing monitoring of wheat stripe rust. The canopy spectrum of winter wheat infected by stripe rust was processed with the difference-in-differences(DID) algorithm used in econometrics. The monitoring accuracies of wheat stripe rust before and after processing with the DID algorithm were compared in the presence of various external factors, disease severity, and several simulated satellite sensors. The correlation between the normalized difference vegetation index processed by the DID algorithm(NDVI-DID) and the disease severity level(SL) increased in comparison with the NDVI before processing. The increase in precision in the natural disease area in the field in the presence of large differences in growth stage, growth, planting, and management of the crop was greater than that in the controlled experiment. For low disease levels(SL < 20%), the R2 of the regression of NDVI-DIDon SL was 38.8% higher than that of the NDVI and the root mean square error(RMSE) was reduced by 11.1%. The increase in precision was greater than that for the severe level(SL > 40%).According to the measured hyperspectral data, the spectral reflectance of three satellite sensor levels was simulated. The wide-band NDVI was calculated. Compared with the wide-band NDVI and vegetation indexes(VI) before DID processing, there were increases in the correlation between SL and the various types of VIS-DID, as well as in the correlation between SL and NDVI-DID. It is feasible to apply the DID algorithm to multispectral satellite data and diverse types of VISfor monitoring wheat stripe rust. Our results improve the quantification of independent effects of stripe rust infection on canopy reflectance spectrum,increase the precision of remote sensing monitoring of wheat stripe rust, and provide a reference for remote sensing monitoring of other crop diseases.

Non-physiological shear stress-induced blood damage in ventricular assist device

Ventricular assist devices(VADs)have been used for treating the end-stage heart failure(HF)patients in the past few decades,which had improved survival rates.In parallel,clinical applications of VADs are accompanied with endangered complications,such as thrombosis,bleeding and infection,which hamper the patient recovery.Nonphysiological shear stress(NPSS)is inevitably created during VAD application.When HF patients implanted with VADs,this high level NPSS can induce damage on blood components including blood cells(red blood cells,platelets,leukocytes et al.)and protein(von Willebrand Factor(VWF)).The damage of these blood cells and proteins may lead to the dysfunction of coagulation and immune systems,contributing to complications in VAD patients.To understand how VADs-created NPSS induces blood damage,and find the link between NPSS-induced blood damage and VAD related complications would potentially help to guide the VAD optimization and to find the effect way for treating VAD associated complications.Here we provide a review to investigate what is currently known about NPSS-induced blood damage within VADs and how the NPSS-induced blood damage links to complications(thrombosis,bleeding and infection)in VAD patients.

Tailored classification of portal vein thrombosis for liver transplantation:Focus on strategies for portal vein inflow reconstruction

Portal vein thrombosis(PVT)is currently not considered a contraindication for liver transplantation(LT),but diffuse or complicated PVT remains a major surgical challenge.Here,we review the prevalence,natural course and current grading systems of PVT and propose a tailored classification of PVT in the setting of LT.PVT in liver transplant recipients is classified into three types,corresponding to three portal reconstruction strategies:Anatomical,physiological and non-physiological.Type I PVT can be removed via low dissection of the portal vein(PV)or thrombectomy;porto-portal anastomosis is then performed with or without an interposed vascular graft.Physiological reconstruction used for type II PVT includes vascular interposition between mesenteric veins and PV,collateral-PV and splenic vein-PV anastomosis.Non-physiological reconstruction used for type III PVT includes cavoportal hemitransposition,renoportal anastomosis,portal vein arterialization and multivisceral transplantation.All portal reconstruction techniques were reviewed.This tailored classification system stratifies PVT patients by surgical complexity,risk of postoperative complications and long-term survival.We advocate using the tailored classification for PVT grading before LT,which will urge transplant surgeons to make a better preoperative planning and pay more attention to all potential strategies for portal reconstruction.Further verification in a large-sample cohort study is needed.

A new way to evaluate thrombotic risk in failure heart and ventricular assist devices

Thrombosis is one of the main complications in patients implanted with ventricular assist device(VAD).The complicated structure and disturbed flow field within failure heart and blood pump play an important role in thrombosis formation.In this study,the influence of Left ventricular(LV)volumes on flow field contributing to thrombosis formation within failure heart and VAD was investigated.Computational Fluid Dynamics(CFD)methods were employed to investigate the effect of different LV volumes on the thrombogenic potential of failure heart and VAD.Lagrangian methods were utilized to obtain information on platelet voyage trajectories.The concepts of mean and threshold of stress accumulation and residence time were introduced to accurately assess the likelihood of thrombus.Eulerian methods were used to identify thrombus-prone locations.CFD results showed that residence time(RT)was the main cause of thrombus formation in the failure heart,and the percentage of platelet trajectories above the RT threshold increased significantly with increasing LV volume.The RT in the left atrial appendage and LV increased significantly with LV volume increasing,which indicated that thrombus is prone to form there.Compared with the failure heart,non-physiological shear stress(NPSS)-caused platelet activation is the main reason for thrombus formation within VAD.The narrow zones(top clearance and secondary flow passage)within VAD have a high incidence of thrombus generation.In VAD patients,the LV volume has an important impact on thrombosis probability within failure heart,in which the larger size of the LV volume is,the higher risk of thrombosis will be.The size of LV volume has little effect on the thrombosis formation probability of VAD,where the NPSS plays the leading role in thrombosis formation.The finding of this study can be utilized to guild the clinical treatment and VAD structure optimization design for reducing the thrombosis risk.

Observation of blood B-type natriuretic peptide level changes in different periods and different cardiac pacing modes

In recent years, the indications of cardiac pacing have extended continuously with the rapid development of pacing technique. Pacemaker treatment has not only limited in arrhythmias of bradycardia and the number of pacemaker treatment has increased year by year. However, more and more new congestive heart failure （ CHF ） and aggravated CHF have appeared in patients after pacing therapy. Therefore, it is a hot topic that how to select reasonable pacing mode to reduce CHF occurrence or relieve CHF symptoms in patients with CHF.