3D Printed TCP-Based Scaffold Incorporating VEGF-Loaded PLGA Microspheres for Craniofacial Tissue Engineering

Objective Vascularization is a critical process during bone regeneration/repair and the lack of tissue vascularization is recognized as a major challenge in applying bone tissue engineeringmethods for cranial and maxillofacial surgeries. The aim of our study is to fabricate a vascular endothelial growth factor (VEGF)-loaded gelatin/alginate/β-TCP composite scaffold by 3D printing method using a computer-assisted design (CAD) model. Methods The paste, composed of (VEGF-loaded PLGA)-containing gelatin/alginate/β-TCP in water, was loaded into standard Nordson cartridges and promptly employed for printing the scaffolds. Rheological characterization of various gelatin/alginate/β-TCP formulations led to an optimized paste as a printable bioink at room temperature. Results The in vitro release kinetics of the loaded VEGF revealed that the designed scaffolds fulfill the bioavailability of VEGF required for vascularization in the early stages of tissue regeneration. The results were confirmed by two times increment of proliferation of human umbilical vein endothelial cells (HUVECs) seeded on the scaffolds after 10 days. The compressive modulus of the scaffolds, 98 ± 11 MPa, was found to be in the range of cancellous bone suggesting their potential application for craniofacial tissue engineering. Osteoblast culture on the scaffolds showed that the construct supports cell viability, adhesion and proliferation. It was found that the ALP activity increased over 50% using VEGF-loaded scaffolds after 2 weeks of culture. Significance The 3D printed gelatin/alginate/β-TCP scaffold with slow releasing of VEGF can be considered as a potential candidate for regeneration of craniofacial defects

A NOVEL METHOD FOR SYNTHESIS OF METASTABLE TETRAGONAL ZIRCONIA NANOPOWDERS AT LOW TEMPERATURES

Zirconia (ZrO2) nanopowder was synthesized using sucrose and fructose as a chelating agent from zirconium hydroxide. The synthesized powders were characterized by X-ray diffraction (XRD), simultaneously thermal analysis (STA), BET surface area, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The above-experimental results showed that the synthesized powders had particle sizes in the range 40-60 nm and mean crystallite sizes of 7-8 nm. Finally, in this research, chelating agents of sucrose and fructose were compared and the obtained results demonstrated that using fructose, nanopowder of zirconia with tetragonal phase was obtained

3D printed tissue engineered model for bone invasion of oral cancer

Recent advances in three-dimensional printing technology have led to a rapid expansion of its applications in tissue engineering. The present study was designed to develop and characterize an in vitro multi-layered human alveolar bone, based on a 3D printed scaffold, combined with tissue engineered oral mucosal model. The objective was to incorporate oral squamous cell carcinoma (OSCC) cell line spheroids to the 3D model at different anatomical levels to represent different stages of oral cancer. Histological evaluation of the 3D tissue model revealed a tri-layered structure consisting of distinct epithelial, connective tissue, and bone layers; replicating normal oral tissue architecture. The mucosal part showed a well-differentiated stratified oral squamous epithelium similar to that of the native tissue counterpart, as demonstrated by immunohistochemistry for cytokeratin 13 and 14. Histological assessment of the cancerous models demonstrated OSCC spheroids at three depths including supra-epithelial level, sub-epithelial level, and deep in the connective tissue-bone interface. The 3D tissue engineered composite model closely simulated the native oral hard and soft tissues and has the potential to be used as a valuable in vitro model for the investigation of bone invasion of oral cancer and for the evaluation of novel diagnostic or therapeutic approaches to manage OSCC in the future

A Novel Approach for Sustainable Supplier Selection Using Differential Evolution: A Case on Pulp and Paper Industry

Abstract. Diverse sustainable supplier selection (SSS) methodologies have been suggested by the practitioners in earlier, to find a solution to the SSS prob-lem. A SSS problem fundamentally is a multi-criteria practice. It is a judgment of tactical significance to enterprises. The nature of this decision usually is dif-ficult and unstructured. Optimization practices might be useful tools for these types of decision-making difficulties. During last few years, Differential Evolu-tion has arisen as a dominating tool used for solving a variety of problems aris-ing in numerous fields. In the current study, we present an approach to find a solution to the SSS problem using Differential Evolution in pulp and paper in-dustry. Hence this paper presents a novel approach is to practice Differential Evolution to select the efficient sustainable suppliers providing the maximum fulfillment for the sustainable criteria determined. Finally, an illustrative exam-ple on pulp and paper industry validates the application of the present ap-proach

Information asymmetry: Evidence from Iran listed companies

Inherent in the International and indigenous accounting standards is managerial discretion in the application of accounting methods, preparation of financial reports and disclosures. Extent literature indicates that almost all companies are engaged in some type of earnings management (Healy, 1985; Perry & Williams, 1994; Defond & Jiambalvo, 1994; Jordon, Clark, & Pate, 2008). A crucial question posed for accounting research is to identify the environmental conditions under which managerial discretion (i.e. accounting choices) are exercised. Using empirical analysis this paper investigates one of the fundamental conditions of earnings management, information asymmetry between managers and investors. When information asymmetry is high, stakeholders including investors do not have sufficient resources, incentives, or access to relevant information to monitor managers’ actions, which gives rise to earnings management. Empirical results show that the level of information asymmetry index which is the combination of five important Tehran Stock Exchange (TSE) relevant proxies (volume of trade, stock price variation, P/E ratio, number of trading days and firm age) has a positive statistically significant effect on the extent of earnings management practiced by companies listed on the TSE

Supplier assessment and selection using fuzzy analytic hierarchy process in a steel manufacturing company

Every organization needs suppliers and no organization can exist without suppliers. Therefore, the organizations approach to suppliers and the selection of the appropriate supplier, its acquisition processes and policies, and its relationships with suppliers, is of vital importance, both to organizations and suppliers alike. No organization can be successful without the support of its supplier base, operationally and strategically, short or long-term.To select the best supplier, it is essential to make an analytical decision based upon tangible and intangible criteria. Chose and management of a supplier has to be congruent with organizational strategy. Therefore, the vision and strategy of the manufacturer are the key drivers for how the supply function will be managed and how supply decisions are made and exectuted. The proposed model in this study was applied in a steel manufacturing company in Malaysia with the goal of reducing time in choosing the correct supplier for the company. This study aims to provide a systematic model stimulating correct supplier selection using the Fuzzy Analytic Hierarchy Process (FAHP) method along with a series of sensitivity analyses which were conducted using the Expert Choice (EC) program to evaluate the impact of changes in the priority of criteria for the suppliers' performance and order quantities. Aims: The main goal of this research is to develop a systematic model towards the best supplier selection. To facilitate the aim of the research, we utilized the Fuzzy Analytic Hierarchy Process, which was a combination of AHP and Fuzzy Theory in order to deal with the uncertainties and vagueness of decision makers's judgement. Study Design: Mention the design of the study here. Place and Duration of Study: The data samples were taken in a steel manufacturing company in Malaysia. Methodology: A Fuzzy Analytic Hierarchy approach is used using a quantitative and qualitative criteria for selecting and evaluating a suitable supplier selection and a six step was conducted to ensure successful implementation. Results: The results indicate that the model is able to assist decision makers to examine the strengths and weaknesses of supplier selection by comparing them with appropriate criteria, sub-criteria and sub sub-criteria. Conclusion: We developed a Fuzzy AHP multi-criteria decision making model for supplier evaluation and selection in the ABC steel company in Malaysia. The advantage of the proposed model over other models like the AHP is that, by adoption of fuzzy numbers, it effectively improves the flexibility of the conventional AHP in dealing with the uncertainty and ambiguity associated with different decision makers's judgments