In situ luminescence measurements of GaN/Al_(2)O_(3) film under different energy proton irradiations

Ion beam-induced luminescence(IBIL) experiments were performed to investigate the in situ luminescence of GaN/Al_(2)O_(3) at varying ion energies,which allowed for the measurement of defects at different depths within the material.The energies of H^(+)were set to 500 keV,640 keV and 2 MeV,the Bragg peaks of which correspond to the GaN film,GaN/Al_(2)O_(3) heterojunction and Al_(2)O_(3) substrate,respectively.A photoluminescence measurement at 250 K was also performed for comparison,during which only near band edge(NBE) and yellow band luminescence in the GaN film were observed.The evolution of the luminescence of the NBE and yellow band in the GaN film was discussed,and both exhibited a decrease with the fluence of H^(+).Additionally,the luminescence of F centers,induced by oxygen vacancies,and Cr^(3+),resulting from the ^(2)E →^(4)A_(2) radiative transition in Al_(2)O_(3),were measured using 2 MeV H^(+).The luminescence intensity of F centers increases gradually with the fluence of H^(+).The luminescence evolution of Cr^(3+)is consistent with a yellow band center,attributed to its weak intensity,and it is situated within the emission band of the yellow band in the GaN film.Our results show that IBIL measurement can effectively detect the luminescence behavior of multilayer films by adjusting the ion energy.Luminescence measurement can be excited by various techniques,but IBIL can satisfy in situ luminescence measurement,and multilayer structural materials of tens of micrometers can be measured through IBIL by adjusting the energy of the inducing ions.The evolution of defects at different layers with ion fluence can be obtained.

Anisodine hydrobromide alleviates oxidative stress caused by hypoxia/reoxygenation in human cerebral microvascular endothelial cells predominantly via inhibition of muscarinic acetylcholine receptor 4

Background:Anisodine hydrobromide(AT3),an anti-cholinergic agent,could be delivered to the brain across the blood-brain barrier and has been used clinically for the treatment of cerebral ischemia/reperfusion injury.Endothelial dysfunction can be caused by hypoxia/reoxygenation(H/R)via oxidative stress and metabolic alterations.The present study investigated whether AT3 regulates the production of nitric oxide(NO)and reactive oxygen species(ROS),and the HIF-1αpathway via regulation of muscarinic acetylcholine receptors(mAChRs)in brain microvascular endothelial cells after H/R exposure.Methods:Under H/R conditions,hCMEC/D3 cerebral microvascular endothelial cells were treated with AT3.Specific inhibitors of M2-and M4-mAChRs were used to explore the mechanism by which AT3 influences oxidative stress in endothelial cells.Then,mAChRs expression was detected by western blotting and NO production was detected by Greiss reaction.The intracellular ROS level was measured using DCFH-DA probes.The expression of hypoxia-inducible transcription factor 1α(HIF-1α)was also detected.Results:While H/R induced the expression of M2-and M4-mAChRs,AT3 suppressed the H/R-upregulated M2-and M4-mAChRs.H/R also induced the production of NO,ROS,and apoptosis.AT3 and M4-mAChR inhibitors inhibited the H/R-induced production of NO and ROS and apoptosis.HIF-1αwas induced by H/R,but was suppressed by AT3.Conclusion:Thus,the in vitro evidence shows that AT3 protects against H/R injury in cerebral microvascular endothelial cells via inhibition of HIF-1α,NO and ROS,predominantly through the downregulation of M4-mAChR.The findings offer novel understandings regarding AT3-mediated attenuation of endothelial cell apoptosis and cerebral ischemia/reperfusion injury.

A novel nine gene signature integrates stemness characteristics associated with prognosis in hepatocellular carcinoma

Cancer stem cells(CSCs)are heterogeneous with self-renewal and differentiation ability.The mRNA expression-based stemness index(mRNAsi)described the similarity between tumor cells and CSCs,which is positively associated with the poor prognosis of cancer patients.However,the key prognostic genes related to mRNAsi in hepatocellular carcinoma(HCC)remains unclear.A 9-gene signature related to mRNAsi and HCC prognosis including PSMG3,SNRPD1,DTYMK,PIGU,NME1,TXNL4A,IPO4,PES1,and REXO4 was obtained.High expression of this signature indicates poor prognosis of HCC.PIGU was an independent prognostic factor of HCC,which was significantly associated with progression of HCC.Among them,DTYMK and NME1 enriched in pyrimidine metabolism,SNRPD1 and TXNL4A enriched in spliceosome and PIGU enriched in glycosyl phosphatidylinositol(GPI)-anchor biosynthesis pathways.High levels of IPO4,NME1,PES1,PIGU and SNRPD1 were closely associated with metastasis of HCC,and low levels of IPO4,PIGU and REOX4 were significantly associated with sorafenib resistance of HCC.High expression of the 9-gene signature was negatively correlated with the stromal cell infiltration,and positively correlated with specific immune subtypes-related to angiogenesis,M1/M2 macrophage polarization,and M2 response.The 9-gene signature was negatively correlated with the stroma,and SNRPD1 and TXNL4 were positively correlated with immune infiltrate.NME1 was negatively correlated with tumor purity.Therefore,a 9-gene signature related to mRNAsi and poor prognosis in HCC were identified,which can be used as biomarkers for the diagnosis of HCC and functional mechanism exploration of CSCs in HCC.These genes such as IPO4 and PIGU might drive the transition of tumor cells into CSCs which possibly controls the balance between metastasis and drug resistance in HCC.The challenge on balance between metastasis and drug resistance for tumor therapy was firstly reported by the present study.

Electrical stimulation with polypyrrole-coated polycaprolactone/silk fibroin scaffold promotes sacral nerve regeneration by modulating macrophage polarisation

Peripheral nerve injury poses a great threat to neurosurgery and limits the regenerative potential of sacral nerves in the neurogenic bladder.It remains unknown whether electrical stimulation can facilitate sacral nerve regeneration in addition to modulate bladder function.The objective of this study was to utilise electrical stimulation in sacra nerve crush injury with newly constructed electroconductive scaffold and explore the role of macrophages in electrical stimulation with crushed nerves.As a result,we generated a polypyrrole-coated polycaprolactone/silk fibroin scaffold through which we applied electrical stimulation.The electrical stimulation boosted nerve regeneration and polarised the macrophages towards the M2 phenotype.An in vitro test using bone marrow derived macrophages revealed that the pro-regenerative polarisation of M2 were significantly enhanced by electrical stimulation.Bioinformatics analysis showed that the expression of signal transducer and activator of transcriptions(STATs)was differentially regulated in a way that promoted M2-related genes expression.Our work indicated the feasibility of electricals stimulation used for sacral nerve regeneration and provided a firm demonstration of a pivotal role which macrophages played in electrical stimulation.

A neurotrophic peptide-functionalized self-assembling peptide nanofiber hydrogel enhances rat sciatic nerve regeneration

Nerve guidance conduit （NGC） is a potential alternative to autologous nerve for peripheral nerve regeneration. A promising therapeutic strategy is to modify the nerve guidance conduit intraluminal microenvironment using physical and/or chemical guidance cues. In this study, a neurotrophic peptide-functionalized self-assembling peptide nanofiber hydrogel that could promote PC12 cell adhesion, proliferation, and neuronal differentiation in vitro was prefilled in the lumen of a hollow chitosan tube （hCST） to accelerate axonal regeneration in a rat sciatic nerve defect model. The functionalized self-assembling peptide was developed by introducing a neurotrophic peptide （RGI, RGIDKRHWNSQ） derived from brain-derived neurotrophic factor （BDNF） to the C-terminus of the self-assembling peptide RADA16-I （Ac-（RADA）4-CONH2）. Morphological, histological, electrophysiological, and functional analyses demonstrated that the RGI-functionalized, self-assembling, peptide nanofiber hydrogel RAD/RGI could produce a neurotrophic microenvironment that markedly improved axonal regeneration with enhanced re-myelination and motor functional recovery.

Load Balancing Algorithm of Controller Based on SDN Architecture Under Machine Learning

With the rapid development of cloud computing and other related services,higher requirements are put forward for network transmission and delay.Due to the inherent distributed characteristics of traditional networks,machine learning technology is diffcult to be applied and deployed in network control.The emergence of SDN technology provides new opportunities and challenges for the application of machine learning technology in network management.A load balancing algorithm of Internet of things controller based on data center SDN architecture is proposed.The Bayesian network is used to predict the degree of load congestion,combining reinforcement learning algorithm to make optimal action decision,self-adjusting parameter weight to adjust the controller load congestion,to achieve load balance,improve network security and stability.