A numerical tool for the reconstruction of the physiological kinematics of the glenohumeral joint.

The aim of this study was to develop and test a robust approach to apply a joint coordinate system (JCS) to imaging data sets of the glenohumeral joint and to reconstruct the kinematics with six degrees of freedom (6DOF) in order to investigate shoulder pathologies related to instability. Visible human data were used to reconstruct bony morphology. Landmarks were used to define axes for body-fixed Cartesian coordinate frames on the humerus and scapula. These were applied to a three-cylinder open-chain JCS upon which the humeral 6DOF motions relative to the scapula were implemented. Software was written that applies 6DOF input variables to rotate and translate the nodes of the surface geometry of the humerus relative to the scapula in a global coordinate frame. The instantaneous relative position and orientation of the humerus for a given set of variables were thus reconstructed on the bone models for graphical display. This tool can be used for graphical animation of shoulder kinematics, demonstrating clinical assessments, and allowing further analysis of the function of tissues within the joint.

Digitally recycled incubators: better economic alternatives to modern systems in low-income countries.

UNLABELLED: The need to maintain a neutral thermal environment is critical to newborn care. AIM: To investigate reasons for the insufficiency of functional incubators and develop a cost-effective technique for using electronic digital components to recycle obsolete incubators in Nigeria. METHODS: Following interview of 84 clinicians and administrators in Nigerian hospitals, it was identified that inadequate funding was the main reason for lack of functional incubators. Two groups of incubator units were then created and their performance compared. Sixteen units of modern (group A) and 19 units of obsolete (group B) incubators were obtained from six hospitals. An assembly design applying independent generic components for recycling systems was specified and produced. These were sourced through the internet at competitive cost and fitted into the reconstructed panels of the obsolete systems. The functional performance of each recycled system was rigorously monitored for 6 months and graded using ten performance indices. The same indices were used to quantify group A systems. RESULTS: The performance of the recycled incubators (group B) was found to be similar to those of modern incubators. Group B's cost index was found to be 25% of that of group A's. CONCLUSION: Appropriate incubator recycling is a cost-effective method of re-equipping hospitals in low-income countries.