Modeling the austenite-ferrite transformation in microalloyed steel P510L

Based on experimental results, the transformation kinetics and cooling characteristics of low-carbon steel were analyzed and modeled to quantitatively link the operational parameters of a process with the properties. From the continuous cooling transformation results, comparisons of the start temperature of austenite-ferrite transformation among three models were analyzed, and the optimal lnk and n, which are the parameters in the Avrami equation, were determined by applying two regression models at different cooling rates. The transformation kinetics during continuous cooling was determined. Furthermore, reasonable agreements between experimental results and predictions were obtained, which can demonstrate the rationality of the established models.

Preparation of porous Ta-10%Nb alloy scaffold and its in vitro biocompatibility evaluation using MC3T3-E1 cells

A highly porous Ta-10%Nb alloy was successfully prepared for tissue engineering via the methods of the sponge impregnation and sintering techniques.The porous Ta-10%Nb alloy offers the capability of processing a pore size of 300-600μm,a porosity of(68.0±0.41)%,and open porosity of(93.5±2.6)%.The alloy also shows desirable mechanical properties similar to those of cancellous bone with the elastic modulus and the comprehensive strength of(2.54±0.5)GPa and(83.43±2.5)MPa,respectively.The morphology of the pores in the porous Ta-Nb alloy shows a good interconnected three-dimension(3D)network open cell structure.It is also found that the rat MC3T3-E1 cell can well adhere,grow and proliferate on the porous Ta-Nb alloy.The interaction of the porous alloy on cells is attributed to its desirable pore structure,porosity and the great surface area.The advanced mechanical and biocompatible properties of the porous alloy indicate that this material has promising potential applications in tissue engineering.

Efficacy of rhNGF-loaded amniotic membrane transplantation for rabbit corneal epithelial and nerve regeneration

AIM:To evaluate the efficacy of recombinant human nerve growth factor-loaded amniotic membrane(rh NGF-AM)on corneal epithelial and nerve regeneration in rabbit model.METHODS:Freshly prepared human amniotic membrane(AM)were immersed into PBS buffer containing 100 or 500μg/mL rh NGF for 15,30,and 60 min at 4℃.The in vitro release kinetics of rh NGF was measured with ELISA.For in vivo evaluation,the AM were immersed with 500μg/mL rh NGF for 30 min.Fifty-seven rabbits were selected to establish corneal epithelial defect model.In addition to the 19 rabbits in control group,38 rabbits received AM transplantation with or without rh NGF after the removal of central epithelium.Corneal epithelial defect area,sub-epithelial nerve fiber density,corneal sensitivity,rh NGF contents in resident AM and corneas were measured after the surgery.RESULTS:rh NGF was sustained release from the AM within 14 d in vitro,with the positive correlation with initial immersion concentration.The immersion of AM in 500μg/mL rh NGF for 30 min achieved the most stable release within 14 d.After transplantation in rabbit cornea,a high concentration of rh NGF in resident rh NGF-AM and cornea was maintained within 8 d.Corneal epithelial healing,nerve fiber regeneration and the recovery of corneal sensitivity were significantly accelerated after the rh NGF-AM transplantation when compared to simple AM transplantation(all P<0.05).CONCLUSION:Simple immersion of AM achieves the sustained release of rh NGF,and promotes corneal epithelial wound healing and nerve regeneration,as well as the recovery of corneal sensitivity in rabbit.

Re-Os age report of pyrrhotite in the Dhi Samir amprophyre-type copper-nickel sulfide deposit in Yemen

1.Objectives The Dhi Samir copper-nickel sulfide deposit is located in the Taiz Province, South Yemen. The ore-bearing rock bodies occurred in the Neoproterozoic magmatic veins (Fig. 1). Different from most magmatic copper-nickel sulfide deposits, the Dhi Samir copper-nickel deposit is produced in the lamprophyre rather than in the mafic-ultramafic rocks such as peridotite, norite and gabbro.

微流控技术在微/纳米材料合成中的研究进展

微/纳米材料因其尺度的微小而具有异于宏观材料的特殊性质,在多个领域都有着丰富的应用.近年来,微流控技术因其微量、高效、高通量、微型化、集成化和自动化等独特的优势在微/纳米材料的合成中引起了广泛的关注.本综述从微反应器的结构形式及反应方式两个角度进行分类,介绍了微流控技术在无机材料、有机材料和复合材料中的具体应用,并对该领域未来的主要发展趋势进行了展望.微流控技术为微/纳米材料的合成提供了新的思路和方法,在工业生产和学术研究中都蕴含着丰富的可能性和巨大的潜力.

Aerolysin Nanopore Identification of Single Nucleotides Using the AdaBoost Model

Nanopores employ the ionic current from the single molecule blockage to identify the structure,conformation,chemical groups and charges of a single molecule.Despite the tremendous development in designing sensitive pore-forming materials,at some extent,the analyte with the single group difference still exhibits similar residual current or duration time.The serious overlap in the statistical results of residual current and duration time brings the difficulties in the nanopore discrimination of each single molecules from the mixture.In this paper,we present the AdaBoost-based machine learning model to identify the multiple analyte with single group difference in the mixed blockages.A set of feature vectors which is obtained from Hidden Markov Model(HMM)is used to train the AdaBoost model.By employing the aerolysin sensing of 5ʹ-AAAA-3ʹ(AA3)and 5ʹ-GAAA-3ʹ(GA3)as the model system,our results show that AdaBoost model increases the identification accu-racy from~0.293 to above 0.991.Furthermore,five sets of mixed blockages of AA3 and GA3 further validate the average accuracy of training and validation,which are 0.997 and 0.989,respectively.The proposed methods improve the capacity of wild-type biological nanopore in efficiently identify the single nucleotide difference without designing of protein and optimizing of the experimental condition.Therefore,the AdaBoost-based machine learning approach could promote the nanopore practical application such as genetic and epigenetic detection.

Exponentially modified Gaussian relevance to the distributions of translocation events in nanopore-based single molecule detection

Nanopore technique plays an important role in single molecule detection, which illuminates the properties of an individual molecule by analyzing the blockage durations and currents. However, the traditional exponential function is lack of efficiency to describe the distributions of blockage durations in nanopore experiments. Herein, we introduced an exponentially modified Gaussian （EMG） function to fit the duration histograms of both simulated events and experimental events. In comparison with the traditional exponential function, our results demonstrated that the EMG provides a better fit while covers the entire range of the distributions. In particular, the fitted parameters of EMG could be directly used to discriminate the sequence length of the oligonucleotides at single molecule level.

Intelligent droplet tracking with correlation filters for digital microfluidics

Tracking the movement of droplets in digital microfluidics is essential to improve its control stability and obtain dynamic information for its applications such as point-of-care testing,environment monitoring and chemical synthesis.Herein,an intelligent,accurate and fast droplet tracking method based on machine vision is developed for applications of digital microfluidics.To continuously recognize the transparent droplets in real-time and avoid the interferes from background patterns or inhomogeneous illumination,we introduced the correlation filter tracker,enabling online learning of the multi-features of the droplets in Fourier domain.Results show the proposed droplet tracking method could accurately locate the droplets.We also demonstrated the capacity of the proposed method for estimation of the droplet velocity as faster as 20 mm/s,and its application in online monitoring the Griess reaction for both colorimetric assay of nitrite and study of reaction kinetics.