Development of Bio Materials for 3-Dimensional Printing Research Paper

Development of Bio Materials for 3-Dimensional Printing - Research Paper Example Prototyping Procedures In general, rapid prototyping (RP) is defined as the process of building or fabrication a physical part, layer by layer directly from its 3-dimensional computer aided design model (Choi and Samavedam, 2001). RP is also known in another term such as layer manufacturing, direct CAD manufacturing, solid freeform fabrication and rapid prototyping and manufacturing (RPM). From these several terms for RP it can be drawn that its basic principle is actually â€Å"additive manufacturing.† It is because the 3D object is being formed by building layer by layer through adding, depositing or solidifying one or more materials in a horizontal layer-wise process (Heynick and Stotz, 2006). Lam et al (2002) described the rapid prototyping (RP) as â€Å"the process of creating three dimensional (3D) objects through repetitive deposition and processing of material layers using computer-controlled equipment †¦ based on the 2D cross-sectional data obtained from slicing a computer-aided design (CAD) model,† (49). ...   The whole model is completed by printing successive 2D profiles on a fresh layer of powder. The profiles of each layer are joined using the printed binder and completed after the removal of the unbound powder and this has been used extensively for the fabrication of drug delivery devices (Wu et al, 1996). Tissue engineers soon caught up and started using 3DP to design and fabricate scaffolds (Wu et al, 1996). Developments include the use of the technology combined with salt leaching technique to fabricate polymeric scaffolds using copolymers of polylactide-coglycolide (PLGA, 85L:15G) and a suitable solvent. Cylindrical scaffolds (F O 8X7 mm) and managed to achieve interconnected porous channels of about 800 ?m and microporosities of 45–150 ?m by using salt leaching. They were able to attach large numbers of hepatocytes on the scaffolds. In a study that investigated cellular reactions to pore size and void fractions based on 3DP fabricated scaffolds, cell proliferation was observed on the scaffolds but varied between cell types and the experimental parameters. The scaffolds used in the experiment had varying pore sizes of 38–150 ?m and void fractions 75% and 90% (Zeltinger et al, 2001). RP is far different from traditional fabrication because this technology is only possible through the aid of the computer which controls all the mechanical system in fabricating 3D objects. Traditional fabrication technique could include solvent casting, gas foaming, fiber bonding/ meshes, phase separation, melt molding, emulsion freeze drying, solution casting, and freeze drying.

Domestic Crime Rate and the Right to Bear Arms Research Paper

Domestic Crime Rate and the Right to Bear Arms - Research Paper Example Furthermore, in Unites States v Cruikshank and Presser v Illinois, the court held that the Second Amendment restricted only the federal government. Several of the state laws relating to the ownership of guns have been upheld on the basis of these decisions (Vernick , Rutkow , Webster , & Teret , 2011, p. 2022). Main Body The Gun Control Act of 1968, provides that no convicted felon should possess firearms. This has been amended by the Lautenberg Amendment, which extends the preclusion of firearms possession to individuals convicted of misdemeanor crimes of domestic violence. This amendment was aimed at preventing the convicted perpetrators of domestic violence from carrying firearms (Guns and domestic violence, 2008, p. B4). In addition, armed domestic abusers pose a very great risk. In fact, around 67% of the females who are killed by firearms have been shot by their intimate partner. The weapon of choice in intimate partner homicide is the firearm. There is a five – fold inc rease of risk of homicide for females, when firearms are present in the home. These are indeed disquieting figures, and such data induced Congress to amend the Gun Control Act on several occasions. For instance, in 1994, an amendment was made to this Act, which precluded any individual subject to a domestic violence protective order, from possessing a firearm. This was followed, in the year 1996, by the Lautenberg Amendment, which prohibited any individual convicted of a misdemeanor crime of domestic violence from possessing a firearm (Wilkinson & Meisner, 2011). However, in the absence of the necessary level of regulation and supervision over entities that could make substantial profits by evading the laws, an effective gun control mechanism cannot be implemented. To its discredit, Congress... The Second Amendment Rights to bear firearms is not an exclusive right granted by the constitution. It does have limitations to provide a restraint on bearing firearms under certain circumstances. The federal law and the laws of many states do not permit an individual who has been convicted of a misdemeanor of domestic violence or who is under a restraining order to possess a firearm. However, there are several shortcomings, when it comes to implementing these laws. There is considerable scope for improving the situation, and there should be proactive initiatives to confiscate weapons from the prohibited intimate partner violence offenders. All the same, laws that preclude the possession of firearms by such individuals, actually bring down instances of domestic homicide. Reckless act of violence could be significantly reduced by having tougher gun control law in place. It would indeed be very helpful, if a license had to be obtained by every purchaser of a handgun. In addition, the l icense should be provided only after the purchaser had completed a course on the responsible use of firearms.