2,229 research outputs found

    Automated fiber placement composite manufacturing: The mission at MSFC's Productivity Enhancement Complex

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    Automated fiber placement is a manufacturing process used for producing complex composite structures. It is a notable leap to the state-of-the-art in technology for automated composite manufacturing. The fiber placement capability was established at the Marshall Space Flight Center's (MSFC) Productivity Enhancement Complex in 1992 in collaboration with Thiokol Corporation to provide materials and processes research and development, and to fabricate components for many of the Center's Programs. The Fiber Placement System (FPX) was developed as a distinct solution to problems inherent to other automated composite manufacturing systems. This equipment provides unique capabilities to build composite parts in complex 3-D shapes with concave and other asymmetrical configurations. Components with complex geometries and localized reinforcements usually require labor intensive efforts resulting in expensive, less reproducible components; the fiber placement system has the features necessary to overcome these conditions. The mechanical systems of the equipment have the motion characteristics of a filament winder and the fiber lay-up attributes of a tape laying machine, with the additional capabilities of differential tow payout speeds, compaction and cut-restart to selectively place the correct number of fibers where the design dictates. This capability will produce a repeatable process resulting in lower cost and improved quality and reliability

    The Textile Place

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    Optically-Based Strain Measuring Orthopaedic Screw for Fracture Fixation Implants

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    Fracture fixation usually involves mechanical fixation with rods, plates and/or screws which repair slowly and are susceptible to infection. Treatment of large defects use allografts which have failure rates of up to 25%, and complication rates as high as 30-60%. Implant infection and loosening are serious concerns, but can currently only be measured through expensive instrumented implants, biopsy culture, or radiographs. None of these directly quantify implant loading and stability however. There is therefore a need for a simple, cost effective way to quantify implant loading and stability in patients. The purpose of our study is to design and evaluate an optically-based strain measuring orthopaedic screw to quantify strain variation in the implant in-vivo after surgery and monitor the load sharing between the bone and the implant. The screw head incorporates a spectral ruler based on Moiré effect which indicates strain. The screw system developed will be able to quantify clinically-relevant bone healing strains in the range of 10-3000μstrains, corresponding to 0.5-150μm change in length for a 5cm gauge. Through this work, we will be able to develop a unique portable tool for physicians to quantify bone healing rather than relying on less quantitative assessments based on pain and radiography

    SED5 encodes a 39-kD integral membrane protein required for vesicular transport between the ER and the Golgi complex

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    HDEL (His-Asp-Glu-Leu) receptor, is essential fo

    Cell-Free Synthesis of the Mitochondrial ADP/ATP Carrier Protein of Neurospora crassa

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    ADP/ATP carrier protein was synthesized in heterologous cell-free systems programmed with Neurospora poly(A)-containing RNA and homologous cell-free systems from Neurospora. The apparent molecular weight of the product obtained in vitro was the same as that of the authentic mitochondrial protein. The primary translation product obtained in reticulocyte lysates starts with formylmethionine when formylated initiator methionyl-tRNA (fMet-tRNAfMet) was present. The product synthesized in vitro was released from the ribosomes into the postribosomal supernatant. The evidence presented indicates that the ADP/ATP carrier is synthesized as a polypeptide with the same molecular weight as the mature monomeric protein and does not carry an additional sequence

    Different Transport Pathways of Individual Precursor Proteins in Mitochondria

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    Transport of mitochondrial precursor proteins into mitochondria of Neurospora crassa was studied in a cellfree reconstituted system. Precursors were synthesized in a reticulocyte lysate programmed with Neurospora mRNA and transported into isolated mitochondria in the absence of protein synthesis. Uptake of the following precursors was investigated: apocytochrome c, ADP/ATP carrier and subunit 9 of the oligomycin-sensitive ATPase. Addition of high concentrations of unlabelled chemically prepared apocytochrome c (1–10 μM) inhibited the appearance in the mitochondrial of labelled cytochrome c synthesized in vitro because the unlabelled protein dilutes the labelled one and because the translocation system has a limited capacity [apparent V is 1–3 pmol × min−1× (mg mitochondrial protein)−1]. Concentrations of added apocytochrome c exceeding the concentrations of precursor proteins synthesized in vitro by a factor of about 104 did not inhibit the transfer of ADP/ATP carrier or ATPase subunit 9 into mitochondria. Carbonylcyanide m-chlorophenylhydrazone, an uncoupler of oxidative phosphorylation, inhibited transfer in vitro of ADP/ATP carrier and of ATPase subunit 9, but not of cytochrome c. These findings suggest that cytochrome c and the other two proteins have different import pathways into mitochondria. It can be inferred from the data presented that different 'receptors' on the mitochondrial surface mediate the specific recognition of precursor proteins by mitochondria as a first step in the transport process

    Using Facebook Advertising to Connect with Extension Audiences

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    There is considerable interest in using social media to reach Extension audiences. The study\u27s main objective was to assess the effectiveness of Facebook promotion and event advertising on creating new client contacts as measured by Likes. The results show the fan base for each county increased slowly prior to and following the Facebook ad, while it increased more rapidly during the advertisement period. Thus, Facebook advertising appears to be an effective tool to increase awareness of Extension Facebook pages. Extension professionals should consider investing in Facebook advertising to expand their fan base

    Requirement of a Membrane Potential for the Posttranslational Transfer of Proteins into Mitochondsria

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    Posttranslational transfer of most precursor proteins into mitochondria is dependent on energization of the mitochondria. Experiments were carried out to determine whether the membrane potential or the intramitochondrial ATP is the immediate energy source. Transfer in vitro of precursors to the ADP/ATP carrier and to ATPase subunit 9 into isolated Neurospora mitochondria was investigated. Under conditions where the level of intramitochondrial ATP was high and the membrane potential was dissipated, import and processing of these precursor proteins did not take place. On the other hand, precursors were taken up and processed when the intramitochondrial ATP level was low, but the membrane potential was not dissipated. We conclude that a membrane potential is involved in the import of those mitochondrial precursor proteins which require energy for intracellular translocatio
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