Case study of assembly defects in manufactured products

Design for Quality Manufacturability (DFQM) is a design tool that empowers engineers to create designs that are easily and effectively transformed into manufactured products. The goal of this methodology is to make designers aware of design characteristics that may lead to product defects during the assembly process. Acknowledging the possibility of these defects will enable the designer to institute design modifications early in the design phase. The benefits realized in this approach are a reduction in the number of defects in the finished product, reduced product cycle times, a reduction in monitoring costs and a reduction in time-to-market. This thesis supports the application of the DFQM methodology as a means of maintaining a competitive advantage within industry. The value of utilizing this approach is proven by the submitted case studies of quality defects. An automobile emergency brake, portable overhead projector, car door handle, hand soap dispenser, floppy disk drive and hand held hair dryer were analyzed using the DFQM classes of Manufacturing Quality Defects. Through this analysis, Influencing Factors and Factor Variables of the each design were isolated and suggestions for modifications were presented to eliminate these quality defects

Topology of the pore-region of a K+ channel revealed by the NMR-derived structures of scorpion toxins

AbstractThe architecture of the pore-region of a voltage-gated K+ channel, Kv1.3, was probed using four high affinity scorpion toxins as molecular calipers. We established the structural relatedness of these toxins by solving the structures of kaliotoxin and margatoxin and comparing them with the published structure of charybdotoxin; a homology model of noxiustoxin was then developed. Complementary mutagenesis of Kv1.3 and these toxins, combined with electrostatic compliance and thermodynamic mutant cycle analyses, allowed us to identify multiple toxin-challel interactions. Our analyses reveals the existence of a shallow vestibule at the external entrance to the pore. This vestibule is ∼28−32A˚wide at its outer margin, ∼28−34A˚wide at its base, and ∼4−8A˚deep. The pore is 9–14A˚wide at its external entrance and tapers to a width of 4–5A˚at a depth of ∼5−7A˚from the vestibule. This structural information should directly aid in developing topological models of the pores of related ion channels and facilitate therapeutic drug design

A method for validating the accuracy of NMR protein structures

We present a method that measures the accuracy of NMR protein structures. It compares random coil index [RCI] against local rigidity predicted by mathematical rigidity theory, calculated from NMR structures [FIRST], using a correlation score (which assesses secondary structure), and an RMSD score (which measures overall rigidity). We test its performance using: structures refined in explicit solvent, which are much better than unrefined structures; decoy structures generated for 89 NMR structures; and conventional predictors of accuracy such as number of restraints per residue, restraint violations, energy of structure, ensemble RMSD, Ramachandran distribution, and clashscore. Restraint violations and RMSD are poor measures of accuracy. Comparisons of NMR to crystal structures show that secondary structure is equally accurate, but crystal structures are typically too rigid in loops, whereas NMR structures are typically too floppy overall. We show that the method is a useful addition to existing measures of accuracy

The relationship between community violence and dating violence in urban adolescents

This study examines dating violence in an urban, ethnically and racially diverse sample of 134 adolescents to determine the relationship among community violence, attitudes toward dating violence, and dating violence. Findings reveal that adolescents in this sample experience a high level of dating and community violence regardless of gender. Community violence predicts physical and psychological dating violence for males and physical dating violence for females. In addition, attitudes toward dating violence predict dating violence for both genders. Specifically, males and females justify physical dating violence under conditions of self defense and humiliation. For males, self defense and humiliation predict psychological dating violence. Results indicate support for using gender specific models to study dating violence. Implications of this study and suggestions for interventions are addressed