Recent advances in cardiovascular stent for treatment of in-stent restenosis:Mechanisms and strategies

Treatments of atherogenesis,one of the most common cardiovascular diseases(CVD),are continuously being made thanks to innovation and an increasingly in-depth knowledge of percutaneous transluminal coronary angioplasty(PTCA),the most revolutionary medical procedure used for vascular restoration.Combined with an expanding balloon,vascular stents used at stricture sites enable the long-time restoration of vascular permeability.However,complication after stenting,in-stent restenosis(ISR),hinders the advancement of vascular stents and are associated with high medical costs for patients for decades years.Thus,the development of a high biocompatibility stent with improved safety and efficiency is urgently needed.This review provides an overview of current advances and potential technologies for the modification of stents for better treatment and prevention of ISR.In particular,the mechanisms of in-stent restenosis are investigated and summarized with the aim to comprehensively understanding the pathogenesis of stent complications.Then,according to different therapeutic functions,the current stent modification strategies are reviewed,including polymeric drug eluting stents,biological friendly stents,prohealing stents,and gene stents.Finally,the review provides an outlook of the challenges in the design of stents with optimal properties.Therefore,this review is a valuable and practical guideline for the development of cardiovascular stents.

Output Feedback Robust H_(∞) Control for Discrete 2D Switched Systems

The two-dimensional(2-D)system has a wide range of applications in different fields,including satellite meteorological maps,process control,and digital filtering.Therefore,the research on the stability of 2-D systems is of great significance.Considering that multiple systems exist in switching and alternating work in the actual production process,but the system itself often has external perturbation and interference.To solve the above problems,this paper investigates the output feedback robust H_(∞)stabilization for a class of discrete-time 2-D switched systems,which the Roesser model with uncertainties represents.First,sufficient conditions for exponential stability are derived via the average dwell time method,when the system’s interference and external input are zero.Furthermore,in the case of introducing the external interference,the weighted robust H_(∞)disturbance attenuation performance of the underlying system is further analyzed.An output feedback controller is then proposed to guarantee that the resulting closed-loop system is exponentially stable and has a prescribed disturbance attenuation levelγ.All theorems mentioned in the article will also be given in the form of linear matrix inequalities(LMI).Finally,a numerical example is given,which takes two uncertain values respectively and solves the output feedback controller’s parameters by the theorem proposed in the paper.According to the required controller parameter values,the validity of the theorem proposed in the article is compared and verified by simulation.

Effect of semi-continuous water washing on the combustion behaviors of agricultural organic solid waste

Combustion of agricultural organic solid waste(AOSW)was an ideal solution for their resource utilization in view of their massive annual production and great potential for reduction of fossil fuel utilization.However,high alkali and alkaline earth metals(AAEMs)content in the feedstock can arose severe fouling and slagging issues and thus prohibiting its vast utilization.In this study,a semi-continuous water washing method was proposed to preliminarily remove AAEMs from agricultural organic solid waste and its effects on the combustion behaviors of washed solid product were investigated.Results showed that the combustion index S were improved to 2.63×10-6,over 68%of the total ashes were removed from the cotton stalk,and 96.3%,89.0%and 74.7%of K,Na and Mg were effectively removed,respectively.Moreover,the softening temperature of low temperature ash from the washed sample was as high as 1450◦C,538◦C higher than the low temperature ash from the original sample;the base acid ratio and fouling index were improved from high slagging and fouling risk(1.7 and 90.8)of the original organic solid waste to low and medium risk(0.4 and 3.5),respectively.All these results signified the contributing effect of proposed semi-continuous water washing method on the combustion of agricultural organic solid waste.In a word,this study provided a promising method for fouling and slagging inhibition during the agricultural organic solid waste combustion.

A high-efficiency and versatile CRISPR/Cas9-mediated HDR-based biallelic editing system

Clustered regulatory interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9 nuclease(Cas9),the third-generation genome editing tool,has been favored because of its high efficiency and clear system composition.In this technology,the introduced double-strand breaks(DSBs)are mainly repaired by non-homologous end joining(NHEJ)or homology-directed repair(HDR)pathways.The high-fidelity HDR pathway is used for genome modification,which can introduce artificially controllable insertions,deletions,or substitutions carried by the donor templates.Although high-level knock-out can be easily achieved by NHEJ,accurate HDR-mediated knock-in remains a technical challenge.In most circumstances,although both alleles are broken by endonucleases,only one can be repaired by HDR,and the other one is usually recombined by NHEJ.For gene function studies or disease model establishment,biallelic editing to generate homozygous cell lines and homozygotes is needed to ensure consistent phenotypes.Thus,there is an urgent need for an efficient biallelic editing system.Here,we developed three pairs of integrated selection systems,where each of the two selection cassettes contained one drug-screening gene and one fluorescent marker.Flanked by homologous arms containing the mutated sequences,the selection cassettes were integrated into the target site,mediated by CRISPR/Cas9-induced HDR.Positively targeted cell clones were massively enriched by fluorescent microscopy after screening for drug resistance.We tested this novel method on the amyloid precursor protein(APP)and presenilin 1(PSEN1)loci and demonstrated up to 82.0%biallelic editing efficiency after optimization.Our results indicate that this strategy can provide a new efficient approach for biallelic editing and lay a foundation for establishment of an easier and more efficient disease model.