The extrusion of section from round billet poses a great challenge for theoretical modeling of the process using upper bound method. The greatest difficulty in three-dimensional upper bound method is to determine kinematically admissible velocity field. The SERR (Spatial Elementary Rigid Region) technique is fairly applicable for analyzing extrusion of sections having re-entrant corners. A modi...

Cyclic polymers display unique physicochemical and biological properties. However, their development is often limited by challenging preparation. In this work, we present a simple route to cyclic poly(?-peptoids) from N-alkylated-N-carboxyanhydrides (NNCA) using LiHMDS promoted ring-expansion polymerization (REP) in DMF. This new method allows the unprecedented use of lysine-like monomers REP d...

We address in this paper several properties of so-called augmented cyclic matrices of weighted digraphs. These matrices arise in different applications of digraph theory to electrical circuit analysis, and can be seen as an enlargement of basic cyclic matrices of the form BWB , where B is a cycle matrix and W is a diagonal matrix of weights. By using certain matrix factorizations and some prope...

Introduction: To investigate Ca(OH)2 extrusion from the apical foramen in relation to the placement mode. Methods: 200 teeth, prepared with ProTaper files with and without apical patency, were divided in Groups A and B respectively, and filled with Ca(OH)2 at 1 and 3 mm short of working length, using K-files manually and with mechanical spiral techniques (Pastinject/Lentulo) at 500 and 700rpm. ...

immature teeth have a large apical opening and thin divergent or parallel dentinal walls; hence, with conventional needle irrigation there is a very high possibility of extrusion. this study was done to compare the apical extrusion of naocl in an immature root delivered using endovac and needle irrigation.eighty freshly extracted maxillary central incisors were decoronated followed by access ca...

Although biodegradable polymers were widely researched, this is the first study considering effect of combined testing environments and cyclic loading on most important aspect related to additive manufacturing : interfacial bond between deposited layers. Its results give confidence in applicability material extrusion technology for biomedical fields , by demonstrating that interface behaves a m...

BACKGROUND AND OBJECTIVE Tissue expansion is a time-tested and frequently used procedure for utilizing local tissue to replace large defects. We aimed to assess the success & complications of tissue expansion in correction of post burn scalp alopecia. METHODS In this study, 30 patients of scalp burn alopecia of 5 to 35 years age group were treated with tissue expansion of the scalp at Bahawal...

OBJECTIVES The objective of this study was to determine the various factors that affect the extrusion rate of ventilation tubes (VTs), including the nature of the middle ear effusion. METHODS A retrospective chart review of 82 pediatric patients (177 ears) who received VT insertion surgery under general anesthesia was carried out to evaluate the relationship between various factors and the VT...