Poly(caprolactone) (PCL) electrospun nanofibers were modified by aminolysis and collagen was immobilized on the aminolysed PCL nanofibers. Considering low immunogenic response collagen elicits, immobilization of the same is anticipated to enhance the tissue engineering application of the PCL nanofibers. Amino groups were introduced into PCL nanofibers through aminolysis process. Aminolysis of PCL nanofibers was confirmed by electron dispersive X‐ray analysis (EDX). Collagen was immobilized on aminolysed PCL nanofibers using glutaraldehyde as crosslinker. The collagen crosslinking on to PCL nanofibers was established by attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy. The fiber morphologies of PCL nanofibers at different stages were characterized by scanning electron microscopy (SEM). The change in hydrophobicity of PCL nanofibers due to aminolysis and collagen immobilization was determined by water contact angle measurements. Aminolysis followed by collagen immobilization had reduced the intrinsic hydrophobicity of PCL nanofibers. NIH 3T3 fibroblasts were cultured for 2 days on PCL nanofibers, aminolysed PCL nanofibers, and aminolysed PCL nanofibers crosslinked with collagen. Cell attachment and growth were observed by MTT assay in each case. Collagen immobilization improved the biocompatibility of the PCL nanofibers. Thus the modified PCL nanofibers can be used as suitable broad spectrum scaffold for skin, cartilage, bone, cardiac constructs for efficient tissue engineering applications. 相似文献
An operationally simple and efficient, one‐pot, two‐step methodology has been developed for the assembly of medicinally important imidazo[1,5‐a]quinoxalines. The protocol involves the multicomponent reaction of aryl aldehydes, ortho‐N‐Boc‐phenylenediamines and azidochalcones in the presence of erbium triflate as a Lewis acid catalyst, followed by deprotection–cyclization with 10% trifluoroacetic acid, furnishing the desired compounds in moderate to good yields. By virtue of their convergence, two aromatic rings and four new bonds are generated during the course of this reaction protocol. The structure of one of the compounds was proved by X‐ray crystallography.
The characteristics of natural convection heat transfer during transient cooldown in 3-dimensional fluid layers and hemispherical cavity have been investigated by means of a finite-difference numerical method. It was found that the turbulent structure and heat transfer characteristics of the unstably-stratified upper wall region are similar for internal heating (IH) case and transient cooldown (TCD) case, except near the cooled bottom wall of fluid layer, and for a small region (φ≤15°) near the bottom of the hemispherical cavity. For most of the surface area of the hemispherical cavity, there is excellent agreement between the heat fluxes calculated for the IH and the TCD cases. Calculations also showed that pseudosteady-state natural convection (PSSNC) is a better model for simulation of volumetric energy sources. 相似文献
A low cost, single-step process employing spray pyrolysis has been developed to deposit selective black nickel coatings on commercially available aluminium and galvanised iron substrates. Parameters for growth have been optimised by a comparative study of the structural, opto-thermal and optical properties of these films. Optimised films of black nickel on aluminium (～ 2300 Å) have α = 0·92 and ε100°C = 0·14 whereas those (～ 2500 Å) on galvanised iron have α = 0·90 and ε100°C = 0·13. The films are seen to be extremely adherent to the substrates and to have stable operational characteristics under temperature cycling up to 280°C in low humidity environments. 相似文献
Journal of Mechanical Science and Technology - In this study we have developed and experimented with two methods of teat detection based on machine learning approach in image recognition and object... 相似文献
Model equations describing the absorption of gas in a liquid film falling down a vertical wall were solved for the case of zero, first, and second order reaction by the method of backward implicit finite difference numerical scheme. The concentration profiles thus obtained were used to evaluate absorption rates and enhancement factors for Newtonian and non-Newtonian fluids. The predicted results were compared with published literature to confirm the validity of the model. Effect of interfacial drag on gas absorption with chemical reaction was also studied. The results indicated that shear stress increases the rate of absorption in case of cocurrent flow and vice versa for countercurrent condition. 相似文献
