Adhesion and corrosion resistance of polycaprolactone coating on NiTi alloy surface after alkali heat pretreatment

Selective laser melting of nickel-titanium alloy(SLM-NiTi)can precisely control the size of the sample molding structure and has attracted extensive attention due to its special superelasticity and shape memory effect.However,the biological inertness and poor corrosion resistance of SLM-NiTi alloy limit their wide application as biomedical implant materials.In this study,polycaprolactone(PCL)coating was prepared on SLM-NiTi alloy by dipping and pulling method,and the effects of alkali heat pretreatment on the morphology,adhesion,corrosion resistance,long-term stability and biomineralisation of the PCL coatings were investigated.The results showed that PCL coating can substan-tially improve the performance of SLM-NiTi alloy,and the PCL coating after alkali heat pretreatment has higher adhesion(increased from 1,747 to 2,498 mN)and lower corrosion current density(reduced by about an order of magnitude compared to PCL coating alone).In addition,the necessary stability,biomineralisation and biocompatibility ability of coatings were also further improved.Therefore,the alkali heat pretreated PCL-coated SLM-NiTi alloy has good application prospects in implants due to its superior properties.

Non-invasive physical therapy as salvage measure for ischemic skin flap:A literature review

This review focuses on the available evidence regarding the molecular mechanisms and treatment potential of several non-surgical physical therapies for managing flap ischemia to propose a non-invasive,economical,and simple treatment to improve flap survival.A review of the literature was conducted on the topics of various non-invasive methods for the treatment of ischemic necrosis of the distal end of the flap between 1988 and 2019.A total of 52 published studies were reviewed on the applications of hyperbaric oxygen therapy,electrical stimulation therapy,heat stress pretreatment,phototherapy,and vibration therapy to manage skin flap necrosis.The underlying molecular mechanisms of these physical therapies on revitalizing the dying skin flaps were discussed and preliminary clinical uses of these therapies to salvage the necrotic skin flaps were pooled and summarized for clarifying the safety and feasibility of these methods.Various physical therapy regimens have been ushered to manage necrotic development in cutaneous flaps.With the refinement of these new technologies and enhancement of related basic science research on vascular revitalization,the prevention and treatment of flap ischemia will enter a new era.

The early signal substances induced by heat stress in brains of mice

To study the effects of early signal substances induced by heat stress in brains of Kunming mice,six-month-old mice(n 572)were pretreated with heat stress and subsequent ischemia/reperfusion by clipping of their bilateral cervical common arteries for 7 min.According to different treatments,animals were randomly divided into four groups:(1)normal control group;(2)heat stress pre-treatment followed by ischemia and reperfusion group(HS/IR);(3)ischemia and reperfusion group(IR);(4)heat stress group(HS).Animals in the later three groups were subdivided into 3 subgroups(1 day,4 days,14 days),respectively.The changes in the expression of cAMP res-ponse element binding protein(CREB)and calcitonin gene-related peptide(CGRP)were detected by immuno-histochemistry and computer image analysis methods.The results showed that compared with the normal group,the expressions of CREB in the hippocampal CA1 region increased significantly in the HS,HS/IR and IR groups(P,0.05).Compared to the normal group,heat stress could result in CGRP excretion and redistribution in the cerebrum,with the highest level in the 4 d HS/IR group.Following heat stress,CGRP immunoreactivity was observed in varicose fibers and neuronal perikarya within the CA1 region.The results indicate that heat stress can induce CREB expression,which in turn stimulates CGRP secretion.