Influences of divalent ion substitution on the magnetic and dielectric properties of W-type barium ferrite

Saturation magnetization,magneto-crystalline anisotropy field,and dielectric properties are closely related to microwave devices applied at different frequencies.For regulating the magnetic and dielectric properties of W-type barium ferrites,single-phase BaMe_(2)Fe_(16)O_(27)(Me=Fe,Mn,Zn,Ni,Co) with different Me ions were synthesized by the high-temperature solid-state method.The saturation magnetization(Ms) range from 47.77 emu/g to 95.34 emu/g and the magnetic anisotropy field(H_a) range from 10700.60 Oe(1 Oe=79.5775 A·m^(-1)) to 13739.57 Oe,depending on the type of cation substitution in the hexagonal lattice.The dielectric permittivity and dielectric loss decrease with increasing frequency of the AC electric field in the low-frequency region,while they almost remain constant in the high-frequency region.The charac teristics of easy regulation and preparation make it a potential candidate for use in microwave device applications.

Specific heat treatment of selective laser melted Ti-6AI-4V for biomedical applications

The ductility of as-fabricated Ti-6AI-4V fails far short of the requirements for biomedical titanium alloy implants and the heat treatment remains the only applicable option for improvement of their mechanical properties. In the present study, the decomposition of as-fabricated martensite was investigated to provide a general understanding on the kinetics of its phase transformation. The decomposition of as- fabricated martensite was found to be slower than that of water-quenched martensite. It indicates that specific heat treatment strategy is needed to be explored for as.fabricated Ti-6AI-4V. Three strategies of heat treatment were proposed based on different phase transformation mechanisms and classified as subtransus treatment, supersolvus treatment and mixed treatment. These specific heat treatments were conducted on selective laser melted samples to investigate the evolutions of microstructure and mechanical properties. The subtransus treatment leaded to a basket-weave structure without changing the morphology of columnar prior β grains. The supersolvus treatment resulted in a lamellar structure and equiaxed β grains. The mixed treatment yielded a microstructure that combines both features of the subtransus treatment and supersolvus treatment. The subtransus treatment is found to be the best choice among these three strategies for as.fabricated Ti-6AI-4V to be used as biomedical implants.

Incorporation of silica nanoparticles to PLGA electrospun fibers for osteogenic differentiation of human osteoblast-like cells

The development of bone tissue engineering scaffolds still remains a challenging field,although various biomaterials have been developed for this purpose.Electrospinning is a promising approach to fabricate nanofibers with an interconnected porous structure,which can support cell adhesion,guide cell proliferation and regulate cell differentiation.The aim of this study is to fabricate composite fibers composed of poly(lactic-co-glycolic acid)(PLGA)and silica nanoparticles(NPs)via electrospinning and investigate the effect of PLGA/SiO_(2)composite fibers on the cellular response of osteoblast-like cells(SaOS-2 cells).SEM and EDX analysis showed that silica NPs were homogenously dispersed in the composite fibers.The mechanical behavior of the fibers showed that silica NPs acted as reinforcements at concentrations of 2.5 and 5 mg/ml.The incorporation of silica NPs led to enhancement of cell attachment and spreading on PLGA/SiO_(2)composite fibers.SaOS-2 cells cultured on PLGA/SiO_(2)composite fibers exhibited increased alkaline phosphatase activity,collagen secretion and bone nodules formation.The bone nodules formation of SaOS-2 cells increased along with the amount of incorporated silica NPs.The present findings indicate that PLGA/SiO_(2)composite fibers can stimulate osteogenic differentiation of SaOS-2 cells and may be a promising candidate scaffold for bone tissue engineering.

Role of eIF4E on epithelial-mesenchymal transition,invasion,and chemoresistance of prostate cancer cells

Dear Editor,Prostate cancer(PCa)is the most common cancer and second leading cause of cancer death for men in the United States[1].PCa with similar Gleason score has been reported to show substantial interpatient heterogeneity and differential prostate cancer-specific mortality rate[2].Such heterogeneity in PCa often results in different therapeutic responses among patients,including therapy resistance,therapeutic failure,relapse,and metastasis[3].Numerous oncogenes,such as eukaryotic translation initiation factor 4E(eIF4E),have been reported to be involved in epithelial-mesenchymal transition(EMT)and/or drug resistance in PCa[4].We previously demonstrated that eIF4E overexpression was involved in chemoresistance of triple-negative breast cancer and silencing eIF4E significantly inhibited cancer cell proliferation and sensitized cancer cells to chemotherapy in a patient-derived xenograft mouse model[5].In addition,eIF4E phosphorylation is known to stimulate the translation of matrix metalloproteinase 3(MMP3)and Snail mRNAs to promote EMT in PCa[6].Furthermore,the complexity and dynamic nature of EMT contributes to the heterogeneity of aggressive cancer cells[7].The precise role of eIF4E in EMT,invasion,and chemoresistance in PCa is still to be established with consideration of different subpopulations in order to develop precision medicine for PCa.In this work,we aimed to explore the role of eIF4E in EMT,invasion,and chemoresistance in PCa for establishing a promising new therapeutic strategy by regulating eIF4E expression using(1-aminoethyl)iminobis[Noleicylcysteinyl-1-aminoethyl)propionamide](ECO)/small interfering RNA(siRNA)nanoparticles previously developed in our lab[8-10]for PCa therapy in the context of tumor heterogeneity.

Nanoparticles and their effects on differentiation of mesenchymal stem cells

Over the past decades,advancements in nanoscience and nanotechnology have resulted in numerous nanomedicine platforms.Various nanoparticles,which exhibit many unique properties,play increasingly important roles in the field of biomedicine to realize the potential of nanomedicine.Due to the capacity of self-renewal and multilineage mesenchymal differentiation,mesenchymal stem cells(MSCs)have been widely used in the area of regenerative medicine and in clinical applications due to their potential to differentiate into various lineages.There are several factors that impact the differentiation of MSCs into different lineages.Many types of biomaterials such as polymers,ceramics,and metals are commonly applied in tissue engineering and regenerative therapies,and they are continuously refined over time.In recent years,along with the rapid development of nanotechnology and nanomedicine,nanoparticles have been playing more and more important roles in the fields of biomedicine and bioengineering.The combined use of nanoparticles and MSCs in biomedicine requires greater knowledge of the effects of nanoparticles on MSCs.This review focuses on the effects of four inorganic or metallic nanoparticles(hydroxyapatite,silica,silver,and calcium carbonate),which are widely used as biomaterials,on the osteogenic and adipogenic differentiation of MSCs.In this review,the cytotoxicity of these four nanoparticles,their effects on osteogenic/adipogenic differentiation of MSCs and the signalling pathways or transcription factors involved are summarized.In addition,the chemical composition,size,shape,surface area,surface charge and surface chemistry of nanoparticles,have been reported to impact cellular behaviours.In this review,we particularly emphasize the influence of their size on cellular responses.We envision our review will provide a theoretical basis for the combined application of MSCs and nanoparticles in biomedicine.