Wear Measurement on Chain Joint Components Using a Roundness Instrument

Driving and timing chains are widely used machine elements which are continuously improved regarding wear and energy efficiency. Especially for timing chains, reducing wear is of high importance as it is critical for the function of the combustion engine. To achieve this goal, the wear in the chain joint has to be measured precisely which is usually done by measuring the length of the entire chain. With this method, no information about the distribution of wear between the contacting bodies, pin and bush, is available. An additional measuring and analyzing technique using a standard roundness instrument is developed with which more detailed information about the wear in the chain joint is obtained. With this method, unworn chain joint components are characterized and the wear on worn components is measured and compared for pins with different surface treatments. Furthermore, approaches to use the measured data in simulation and calculation are presented

Quality requirements for reclaimed/recycled water

Water used during current and previous space missions has been either carried or made aloft. Future human space endeavors will require some form of water reclamation and recycling. There is little experience in the U.S. space program with this technology. Water reclamation and recycling constitute engineering challenges of the broadest nature that will require an intensive research and development effort if this technology is to mature in time for practical use on the proposed U.S. Space Station. In order for this to happen, reclaimed/recycled water specifications will need to be devised to guide engineering development. Present NASA Potable Water Specifications are not applicable to reclaimed or recycled water. Adequate specifications for ensuring the quality of the reclaimed or recycled potable water system is reviewed, limitations of present water specifications are examined, world experience with potable water reclamation/recycling systems and systems analogs is reviewed, and an approach to developing pertinent biomedical water specifications for spacecraft is presented. Space Station water specifications should be designed to ensure the health of all likely spacecraft inhabitants including man, animals, and plants

Genome-scale architecture of small molecule regulatory networks and the fundamental trade-off between regulation and enzymatic activity

Metabolic flux is in part regulated by endogenous small molecules that modulate the catalytic activity of an enzyme, e.g., allosteric inhibition. In contrast to transcriptional regulation of enzymes, technical limitations have hindered the production of a genome-scale atlas of small molecule-enzyme regulatory interactions. Here, we develop a framework leveraging the vast, but fragmented, biochemical literature to reconstruct and analyze the small molecule regulatory network (SMRN) of the model organism Escherichia coli, including the primary metabolite regulators and enzyme targets. Using metabolic control analysis, we prove a fundamental trade-off between regulation and enzymatic activity, and we combine it with metabolomic measurements and the SMRN to make inferences on the sensitivity of enzymes to their regulators. Generalizing the analysis to other organisms, we identify highly conserved regulatory interactions across evolutionarily divergent species, further emphasizing a critical role for small molecule interactions in the maintenance of metabolic homeostasis.P30 CA008748 - NCI NIH HHS; R01 GM121950 - NIGMS NIH HH

Adapted Pool Cue

Our primary goal was to develop an adaptive device to allow a user with limited upper body mobility to more effectively play a game of pool. Within this goal it was important to design around the concept of a least restrictive environment, in order to provide the user with as close to a standard pool playing experience as possible. The device was designed to specifically meet the needs of John Lee, an Assistive Technology Specialist at Cal Poly\u27s Disability Resource Center. Mr. Lee has muscular dystrophy, which limits his upper and lower body mobility and currently requires his use of a wheelchair. Research into the specific needs of our customer, current products, and pool game elements was performed to better understanding of the project goals. From this research and discussion with John Lee, customer requirements and engineering specifications were developed. These were then used to guide the design development process. Several ideation techniques were used, and concepts for a bridge mechanism and supporting bases were created. A rough prototype was developed to test the concepts before our final design direction was decided. Our final design acts as a robust bridge device with a self-supporting base that constrains the path of the pool cue to a set path, allowing the user to focus their effort on providing power to the shot. The base can be rolled around the table, and stabilizing posts are lowered through a cable system when the shot is being made to prevent the base from sliding. The shooting mechanism features horizontal and vertical angle adjustment to allow for proper positioning of the cue, as well as a small cue stop to adjust the allowable travel of the pool cue. A vertical height adjustment is also present to allow the mechanism to reach over the edge of the pool table and for special high angle shots. The shooting mechanism itself features fixed and sliding rollers that act as a modified pool bridge, limiting travel of the pool cue to one axis of motion. The top part of the device can be separated from the base and clamped to the upright post for easier transport. These design choices allow the device to be compatible with any size regulation pool cue. Engineering analysis was performed to select materials and size components for the final device. Parts were specified and costs recorded to keep within the program budget. The device was then manufactured to the specifications shown in the included technical drawings, and testing was performed to verify that the final product met the design requirements. The overall experience was successful, and the final product received strong approval from John Lee. Recommendations for potential future improvement of both manufacturing and design of the device are included, as are as tips for device operation

A comprehensive study of infrared OH prompt emission in two comets. I. Observations and effective g-factors

We present high-dispersion infrared spectra of hydroxyl (OH) in comets C/2000 WM1 (LINEAR) and C/2004 Q2 (Machholz), acquired with the Near Infrared Echelle Spectrograph at the Keck Observatory atop Mauna Kea, Hawaii. Most of these rovibrational transitions result from photodissociative excitation of H_2O giving rise to OH "prompt" emission. We present calibrated emission efficiencies (equivalent g-factors, measured in OH photons s^(-1) [H_2O molecule]^(-1)) for more than 20 OH lines sampled in these two comets. The OH transitions analyzed cover a broad range of rotational excitation. This infrared database for OH can be used in two principal ways: (1) as an indirect tool for obtaining water production in comets simultaneously with the production of other parent volatiles, even when direct detections of H_2O are not available; and (2) as an observational constraint to models predicting the rotational distribution of rovibrationally excited OH produced by water photolysis

From natural to artificial metalloproteins – Challenges and opportunities

Organometallic catalysts are used in a wide range of industrially important reactions. By immobilizing such catalysts to a protein (Fig. 1), we can bring them into aqueous media, fine-tune activities and selectivities and overcome the challenges associated with trace metal removal in the product fraction [1, 2]. Trace metal removal is particularly important for the synthesis of pharmaceutical compounds. Typically, the transition metal content should be below 10 ppm. We have employed two types of metal catalysts, a Ru-based Grubbs-Hoveyda-type catalyst for olefin metathesis and a Rh-catalyst for phenylacetylene polymerization. These catalysts were covalently attached to either nitrobindin (NB) [3] or ferric hydroxamate uptake protein component: A (FhuA) [4] β-barrel proteins, yielding biohybrid catalysts (also denoted artificial metalloproteins) that can be immersed in aqueous reaction media either in their free form or immobilized to bacterial cells. Moreover, we could show that the metal catalysts can be immobilized on surfaces consisting of silica or polypropylene via peptide-based adhesion promoters, thereby enabling “green” surface immobilization strategies with the potential of catalyst recycling [5]. Either strategy yielded highly active catalysts that show great promise for single or sequential one-pot reactions. Separation of products and the catalysts was readily achieved by extraction. With the potential to tune reaction efficiencies and selectivities by modifying either the metal catalyst or the protein surrounding, biohybrid catalysts bear great potential to amend or even substitute the repertoire of reactions available by organic synthesis and, likewise, biocatalysis. Please click Additional Files below to see the full abstract

Crystal structure of Mycobacterium tuberculosis ClpP1P2 suggests a model for peptidase activation by AAA+ partner binding and substrate delivery

Caseinolytic peptidase P (ClpP), a double-ring peptidase with 14 subunits, collaborates with ATPases associated with diverse activities (AAA+) partners to execute ATP-dependent protein degradation. Although many ClpP enzymes self-assemble into catalytically active homo-tetradecamers able to cleave small peptides, the Mycobacterium tuberculosis enzyme consists of discrete ClpP1 and ClpP2 heptamers that require a AAA+ partner and protein–substrate delivery or a peptide agonist to stabilize assembly of the active tetradecamer. Here, we show that cyclic acyldepsipeptides (ADEPs) and agonist peptides synergistically activate ClpP1P2 by mimicking AAA + partners and substrates, respectively, and determine the structure of the activated complex. Our studies establish the basis of heteromeric ClpP1P2 assembly and function, reveal tight coupling between the conformations of each ring, show that ADEPs bind only to one ring but appear to open the axial pores of both rings, provide a foundation for rational drug development, and suggest strategies for studying the roles of individual ClpP1 and ClpP2 rings in Clp-family proteolysisNational Institutes of Health (U.S.) (NIH Grant GM-101988)Brown UniversityNational Science Foundation (U.S.) (CAREER award)National Institute of General Medical Sciences (U.S.) (Grant P41 GM103403)United States. Dept. of Energy (Contract DE-AC02-06CH11357

Organelle-specific isoenzymes of plant V-ATPase as revealed by in vivo-FRET analysis

Seidel T, Schnitzer D, Golldack D, Sauer M, Dietz K-J. Organelle-specific isoenzymes of plant V-ATPase as revealed by in vivo-FRET analysis. BMC Cell Biology. 2008;9(1): 28.BACKGROUND: The V-ATPase (VHA) is a protein complex of 13 different VHA-subunits. It functions as an ATP driven rotary-motor that electrogenically translocates H+ into endomembrane compartments. In Arabidopsis thaliana V-ATPase is encoded by 23 genes posing the question of specific versus redundant function of multigene encoded isoforms. RESULTS: The transmembrane topology and stoichiometry of the proteolipid VHA-c" as well as the stoichiometry of the membrane integral subunit VHA-e within the V-ATPase complex were investigated by in vivo fluorescence resonance energy transfer (FRET). VHA-c", VHA-e1 and VHA-e2, VHA-a, VHA-c3, truncated variants of VHA-c3 and a chimeric VHA-c/VHA-c" hybrid were fused to cyan (CFP) and yellow fluorescent protein (YFP), respectively. The constructs were employed for transfection experiments with Arabidopsis thaliana mesophyll protoplasts. Subcellular localization and FRET analysis by confocal laser scanning microscopy (CLSM) demonstrated that (i.) the N- and C-termini of VHA-c" are localised in the vacuolar lumen, (ii.) one copy of VHA-c" is present within the VHA-complex, and (iii.) VHA-c" is localised at the ER and associated Golgi bodies. (iv.) A similar localisation was observed for VHA-e2, whereas (v.) the subcellular localisation of VHA-e1 indicated the trans Golgi network (TGN)-specifity of this subunit. CONCLUSION: The plant proteolipid ring is a highly flexible protein subcomplex, tolerating the incorporation of truncated and hybrid proteolipid subunits, respectively. Whereas the membrane integral subunit VHA-e is present in two copies within the complex, the proteolipid subunit VHA-c" takes part in complex formation with only one copy. However, neither VHA-c" isoform 1 nor any of the two VHA-e isoforms were identified at the tonoplast. This suggest a function in endomembrane specific VHA-assembly or targeting rather than proton transport

The structure of epitaxial V2O3 films and their surfaces : a medium energy ion scattering study

Medium energy ion scattering, using 100 keV H+ incident ions, has been used to investigate the growth of epitaxial films, up to thicknesses of ~200 Å, of V2O3 on both Pd(111) and Au(111). Scattered-ion energy spectra provide a measure of the average film thickness and the variations in this thickness, and show that, with suitable annealing, the crystalline quality is good. Plots of the scattering yield as a function of scattering angle, so-called blocking curves, have been measured for two different incidence directions and have been used to determine the surface structure. Specifically, scattering simulations for a range of different model structures show poor agreement with experiment for half-metal (….V’O3V) and vanadyl (….V’O3V=O) terminations, with and without surface interlayer relaxations. However, good agreement with experiment is found for the modified oxygen-termination structure, first proposed by Kresse et al., in which a subsurface V half-metal layer is moved up into the outermost V buckled metal layer to produce a VO2 overlayer on the underlying V2O3, with an associated layer structure of ….O3VV’’V’O3