The role of microRNAs in bone remodeling

Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existing evidence indicates that micro RNAs（mi RNAs）, known as a family of short non-coding RNAs, are the key post-transcriptional repressors of gene expression,and growing numbers of novel mi RNAs have been verified to play vital roles in the regulation of osteogenesis, osteoclastogenesis,and adipogenesis, revealing how they interact with signaling molecules to control these processes. This review summarizes the current knowledge of the roles of mi RNAs in regulating bone remodeling as well as novel applications for mi RNAs in biomaterials for therapeutic purposes.

Monte Carlo simulation for performance evaluation of detector model with a monolithic LaBr_(3)(Ce)crystal and SiPM array forγradiation imaging

In recent years,LaBr_(3)(Ce)crystals and silicon photomultipliers(SiPMs)have been increasingly used in radiation imaging.This study involved the establishment of a detector model with a monolithic LaBr_(3)(Ce)crystal and SiPM array forγ-radiation imaging on the GEANT4 platform.The optical process included in the detector model was defined by key parameters,such as the emission spectrum,scintillation yield,and intrinsic resolution of the LaBr_(3):5%Ce crystal,as well as the detection efficiency of the SiPM array.The response of the detector model to^(57)Co flooded field irradiation was simulated and evaluated.The radiation images generated by the detector model exhibited a compression effect that was very close to that on images acquired by the physical detector.The spatial resolution of the simulated detector closely approximates that of the physical experiment.A detector model without the optical process was also established for comparison with a detector using the optical process.Both were used in a near-field modified uniform redundant array(MURA)imaging system to acquire images of a point source and a ring source of^(57)Co at the center of the field-of-view of the imaging system.The spatial resolution and signal-to-noise ratio of the images that were reconstructed using the two detector models were determined and compared.Compared with the detector model without optical processes,although the images from the proposed detector model have slightly inferior signal-to-noise ratios and more artifacts,they are more consistent with the reconstructed versions of images acquired in real physical experiments.The results confirm that the detector model can be used to design aγ-radiation imaging detector and to develop an imaging algorithm that can significantly shorten the development time and reduce the cost.

A Study on the Wear Resistance of Nano-Material/E51

Epoxy resin modified by nanometric γ-alumina or multi-walled carbon nanotubes (MCNTs) was prepared with solution mixingmethod, and the wear resistance of the composite was studied. The results show that when an optimum amount of nanometricalumina or MCNTs is filled in epikote51 (E51), the wear resistance of the composite will increase. When 8 wt pct nanometricγ-alumina is filled in E51, the wear resistance of the composite increases to 230%. When 10% MCNTs is filled in E51, thewear resistance of the composite increases to 226%. When nanometric alumina is filled in, the wear resistance of modifiedepikote51 will increase as the cure temperature is heightened.

Electrically-manipulable electron-momentum filter based on antiparallel asymmetric doubleδ-magnetic-barrier semiconductor microstructure

We theoretically investigate the wave-vector filtering(WVF)effect for electrons in an antiparallel asymmetric doubleδ-magnetic-barrier microstructure under a bias,which can be fabricated experimentally by patterning two asymmetric ferromagnetic(FM)stripes on the top and the bottom of GaAs/AlxGa1−xAs heterostructure,respectively.It is found that an appreciable WVF effect appears because of an essentially two-dimensional(2D)process for electrons across this microstructure.WVF effect is found to be sensitive to the applied bias.WVF efficiency can be tuned by changing bias,which may lead to an electrically-controllable momentum filter for nanoelectronics device applications.

Bright InP quantum dots by Ga-doping for red emitters

Environment-friendly indium phosphide(InP)-based quantum dots(QDs)with efficient red-emitting properties are sufficiently needed to satisfy the requirement of burgeoning display and lighting technology.Currently,the syntheses of InP QDs using tris(trimethylsilyl)phosphine as the precursor are highly toxic and expensive.Herein,we successfully introduced gallium(Ga)ions into tris(dimethylamino)phosphine-based red InP cores through thermally-promoted cation exchange,and the obtained Ga-doped InP cores exhibited significantly increased photoluminescence quantum yields(PLQY)of up to 26%.The existence of Ga was directly confirmed by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy,and the functions of Ga were systematically studied.After subsequent coating of Ga-doped InP cores with ZnSeS and ZnS shells,the resulting Ga-InP/ZnSeS/ZnS QDs achieved a high PLQY of 62%with an emission maximum at 640 nm.In contrast,without Ga-doping,the PLQY only attained 36%using the same synthetic approach.This indicated an approximate 1.7-fold increase in PLQY.The enhancement of photoluminescence was related to the Ga^(3+),as it not only passivated surface defects of InP cores but also reduced core–shell interface stress.The Ga-InP/ZnSeS/ZnS QDs exhibited good stability towards heat treatment and ultraviolet(UV)irradiation.Moreover,the red light-emitting diode(LED)based on Ga-InP/ZnSeS/ZnS QDs performed well in a wide injected current range of 2 to 200 mA,with a maximum power efficiency of 0.68 lm/W.This work showcases Ga-doping through cation exchange as a promising strategy for enhancing the efficiency of InP-based red emitters.

Manipulation of a temporal electron-spin splitter via aδ-potential in an embedded magnetic-electric-barrier microstructure

We theoretically explore the manipulation of a temporal electron-spin splitter by aδ-potential in an embedded magnetic-elec tric-barrier micro structure(EMEBM),which is constructed by patterning a ferromagnetic stripe and a Schottky-metal stripe on the top and bottom of an InAs/Al_(x)In_(1-x)As heterostructure,respectively.Spin polarization of the dwell time remains,even though aδ-potential is inserted by atomic-layer doping.Both the magnitude and sign of the spinpolarized dwell time can be manipulated by changing the weight or position of the 6-potential.Thus,a structurally controllable temporal electron-spin splitter can be obtained for spintronics device applications.