Manufacture of Compliant Prosthesis Sockets using Selective Laser Sintering 565

Solid Freeform Fabrication to date has largely been applied in prototype fabrication or fabrication of patterns for conventional manufacturing methods. However, many opportunities exist for using SFF for manufacturing the actual product. In particular, those applications that require or can be enhanced by custom geometric design seem to be well suited for SFF techniques. In this paper we describe the design of a prosthesis socket for a below-the-knee amputee. This socket is specifically designed to provide compliance in selected areas to enhance the comfort of the wearer. Additionally, the socket contains an integrated pylon fitting that provides a structurally superior connection while also improving the comfort of the wearer. The socket was manufactured using selective laser sintering, mated to a pylon and foot, and fitted to the patient for gait analysis. The results of the analysis indicate an improved fit is possible with manufacture by SLS.The authors acknowledge the support of the Veterans Administration for partial support of this work.Mechanical Engineerin

Finite Element Structural Analysis of Prosthesis Sockets for Below-the-Knee Amputees Manufactured Using SLS

A very attractive application of Solid Freeform Fabrication is manufacture of prosthesis sockets for below-the-knee amputees. The custom geometric design required is very compatible with SFF techniques. The present work focuses on finite element analysis of sockets manufactured by Selective Laser Sintering using Duraform as the material. The objective is to ensure reliability of the sockets for their use by patients. This paper describes the finite element models developed for the sockets, as well as the derivation of realistic boundary conditions that may allow a simulation of the structure under regular workloads.Mechanical Engineerin

Clinical Evaluation of Prosthetic Sockets Manufactured by Selective Laser Sintering

A pilot study was undertaken to evaluate the clinical acceptance of prosthetic limb sockets manufactured using solid freeform fabrication (SFF). The fabrication of sockets for amputees is a natural application for SFF. The socket is the part of the prosthetic limb that fits onto the amputee’s residual limb. Each socket is custom manufactured for each individual amputee. Four amputees were successfully fit with sockets created using selective laser sintering. The scope of the study included software development, finite element analysis, materials testing, and clinical evaluation. This paper discusses socket design issues and clinical testing results.Mechanical Engineerin

Antiphospholipid autoantibodies as blood biomarkers for detection of early stage Alzheimer's disease

A robust blood biomarker is urgently needed to facilitate early prognosis for those at risk for Alzheimer's disease (AD). Redox reactive autoantibodies (R-RAAs) represent a novel family of antibodies detectable only after exposure of cerebrospinal fluid (CSF), serum, plasma or immunoglobulin fractions to oxidizing agents. We have previously reported that R-RAA antiphospholipid antibodies (aPLs) are significantly decreased in the CSF and serum of AD patients compared to healthy controls (HCs). These studies were extended to measure R-RAA aPL in serum samples obtained from Alzheimer's Disease Neuroimaging Initiative (ADNI). Serum samples from the ADNI-1 diagnostic groups from participants with mild cognitive impairment (MCI), AD and HCs were blinded for diagnosis and analyzed for R-RAA aPL by ELISA. Demographics, cognitive data at baseline and yearly follow-up were subsequently provided by ADNI after posting assay data. As observed in CSF, R-RAA aPL in sera from the AD diagnostic group were significantly reduced compared to HC. However, the sera from the MCI population contained significantly elevated R-RAA aPL activity relative to AD patient and/or HC sera. The data presented in this study indicate that R-RAA aPL show promise as a blood biomarker for detection of early AD, and warrant replication in a larger sample. Longitudinal testing of an individual for increases in R-RAA aPL over a previously established baseline may serve as a useful early sero-epidemiologic blood biomarker for individuals at risk for developing dementia of the Alzheimer's type

Design and Analysis of Orthogonally Compliant Features for DuraForm/SLS Manufactured Plates

In many applications of parts manufactured by Solid Freeform Fabrication (SFF), compliance is an important factor. In order to achieve given deformation goals with optimal shape, the design of compliant mechanisms and elements fabricated with SFF techniques must take into account the particular constraints and boundary conditions of the target application as well as the specific material properties of the part. The present work focuses on the design and evaluation of compliant features for a geometrically constrained thin-wall part subject to loads normal to its tangent plane. Such features would need to be embedded in the object. The manufacture of prosthetic sockets for lower-limb amputees is the specific application presented, where greater compliance is needed at sites in contact with pressure sensitive tissues. Sample parts were fabricated by selective laser sintering, and the material used was Duraform.The authors gratefully acknowledge financial support for this work from the VA Rehabilitation Research and Development Service.Mechanical Engineerin

AndrewAnnex/SpiceyPy: SpiceyPy-1.1.0.dev0

draft release of 1.1.0.dev0, in preparation of v1.1.

AndrewAnnex/SpiceyPy: SpiceyPy 1.1.1

Last release to feature N65 Spice, future releases will target N66 Added added python3.6 builds Fixed fixed formatting on changelog fixed issues with rtd builds Changed version updated converted all downloads to use http

An Ion‐Pairing Approach to Stereoselective Metal‐Free Ring‐Opening Metathesis Polymerization

Stereochemistry can have a profound impact on polymer and materials properties. Unfortunately, straightforward methods for realizing high levels of stereocontrolled polymerizations are often challenging to achieve. In a departure from traditional metal‐mediated ring‐opening metathesis polymerization (ROMP), we discovered a remarkably simple method for controlling alkene stereochemistry in photoredox mediated metal‐free ROMP. Ion‐pairing, initiator sterics, and solvation effects each had profound impact on the stereochemistry of polynorbornene (PNB). Simple modifications to the reaction conditions produced PNB with trans alkene content of 25 to >98 %. High cis content was obtained from relatively larger counterions, toluene as solvent, low temperatures (−78 °C), and initiators with low Charton values. Conversely, smaller counterions, dichloromethane as solvent, and enol ethers with higher Charton values enabled production of PNB with high trans content. Data from a combined experimental and computational investigation are consistent with the stereocontrolling step of the radical cationic mechanism proceeding under thermodynamic control.Stereoselective ring‐opening metathesis polymerization is achieved by non‐covalent interactions, such as ion‐pairing, initiator sterics and solvation effects, in a metal‐free condition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/168301/1/anie202016393.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168301/2/anie202016393_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168301/3/anie202016393-sup-0001-misc_information.pd

An Ion‐Pairing Approach to Stereoselective Metal‐Free Ring‐Opening Metathesis Polymerization

Stereochemistry can have a profound impact on polymer and materials properties. Unfortunately, straightforward methods for realizing high levels of stereocontrolled polymerizations are often challenging to achieve. In a departure from traditional metal‐mediated ring‐opening metathesis polymerization (ROMP), we discovered a remarkably simple method for controlling alkene stereochemistry in photoredox mediated metal‐free ROMP. Ion‐pairing, initiator sterics, and solvation effects each had profound impact on the stereochemistry of polynorbornene (PNB). Simple modifications to the reaction conditions produced PNB with trans alkene content of 25 to >98 %. High cis content was obtained from relatively larger counterions, toluene as solvent, low temperatures (−78 °C), and initiators with low Charton values. Conversely, smaller counterions, dichloromethane as solvent, and enol ethers with higher Charton values enabled production of PNB with high trans content. Data from a combined experimental and computational investigation are consistent with the stereocontrolling step of the radical cationic mechanism proceeding under thermodynamic control.Stereoselective ring‐opening metathesis polymerization is achieved by non‐covalent interactions, such as ion‐pairing, initiator sterics and solvation effects, in a metal‐free condition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/168301/1/anie202016393.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168301/2/anie202016393_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168301/3/anie202016393-sup-0001-misc_information.pd

An Ion‐Pairing Approach to Stereoselective Metal‐Free Ring‐Opening Metathesis Polymerization

Stereochemistry can have a profound impact on polymer and materials properties. Unfortunately, straightforward methods for realizing high levels of stereocontrolled polymerizations are often challenging to achieve. In a departure from traditional metal‐mediated ring‐opening metathesis polymerization (ROMP), we discovered a remarkably simple method for controlling alkene stereochemistry in photoredox mediated metal‐free ROMP. Ion‐pairing, initiator sterics, and solvation effects each had profound impact on the stereochemistry of polynorbornene (PNB). Simple modifications to the reaction conditions produced PNB with trans alkene content of 25 to >98 %. High cis content was obtained from relatively larger counterions, toluene as solvent, low temperatures (−78 °C), and initiators with low Charton values. Conversely, smaller counterions, dichloromethane as solvent, and enol ethers with higher Charton values enabled production of PNB with high trans content. Data from a combined experimental and computational investigation are consistent with the stereocontrolling step of the radical cationic mechanism proceeding under thermodynamic control.Stereoselective ring‐opening metathesis polymerization is achieved by non‐covalent interactions, such as ion‐pairing, initiator sterics and solvation effects, in a metal‐free condition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/168268/1/ange202016393.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168268/2/ange202016393_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168268/3/ange202016393-sup-0001-misc_information.pd