Science.gov

Sample records for 204-ar waste unloading

  1. Calculation notes that support accident scenario and consequence development for the leak from a railcar/tank trailer at the 204-ar waste unloading facility

    SciTech Connect

    Ryan, G.W., Westinghouse Hanford

    1996-09-19

    This document supports the development and presentation of the following accident scenario in the TWRS Final Safety Analysis Report: Leak from Railcar/Tank Trailer. The calculations needed to quantify the risk associated with this accident scenario are included within.

  2. Bootstrap unloader

    NASA Technical Reports Server (NTRS)

    Pfiffner, H. J.

    1969-01-01

    Circuit can sample a number of transducers in sequence without drawing from them. This bootstrap unloader uses a differential amplifier with one input connected to a circuit which is the equivalent of the circuit to be unloaded, and the other input delivering the proper unloading currents.

  3. REACTOR UNLOADING

    DOEpatents

    Leverett, M.C.

    1958-02-18

    This patent is related to gas cooled reactors wherein the fuel elements are disposed in vertical channels extending through the reactor core, the cooling gas passing through the channels from the bottom to the top of the core. The invention is a means for unloading the fuel elements from the core and comprises dump values in the form of flat cars mounted on wheels at the bottom of the core structure which support vertical stacks of fuel elements. When the flat cars are moved, either manually or automatically, for normal unloading purposes, or due to a rapid rise in the reproduction ratio within the core, the fuel elements are permtted to fall by gravity out of the core structure thereby reducing the reproduction ratio or stopping the reaction as desired.

  4. River Protection Project (RPP) Dangerous Waste Training Plan

    SciTech Connect

    POHTO, R.E.

    2000-03-09

    This supporting document contains the training plan for dangerous waste management at River Protection Project TSD Units. This document outlines the dangerous waste training program developed and implemented for all Treatment, Storage, and Disposal (TSD) Units operated by River Protection Project (RPP) in the Hanford 200 East, 200 West and 600 Areas and the <90 Day Accumulation Area at 209E. Operating TSD Units managed by RPP are: the Double-Shell Tank (DST) System, 204-AR Waste Unloading Facility, Grout, and the Single-Shell Tank (SST) System. The program is designed in compliance with the requirements of Washington Administrative Code (WAC) 173-303-330 and Title 40 Code of Federal Regulations (CFR) 265.16 for the development of a written dangerous waste training program and the Hanford Facility Permit. Training requirements were determined by an assessment of employee duties and responsibilities. The RPP training program is designed to prepare employees to operate and maintain the Tank Farms in a safe, effective, efficient, and environmentally sound manner. In addition to preparing employees to operate and maintain the Tank Farms under normal conditions, the training program ensures that employees are prepared to respond in a prompt and effective manner should abnormal or emergency conditions occur. Emergency response training is consistent with emergency responses outlined in the following Building Emergency Plans: HNF-IP-0263-TF and HNF-=IP-0263-209E.

  5. TDRSS momentum unload planning

    NASA Technical Reports Server (NTRS)

    Cross, George R.; Potter, Mitchell A.; Whitehead, J. Douglass; Smith, James T.

    1991-01-01

    A knowledge-based system is described which monitors TDRSS telemetry for problems in the momentum unload procedure. The system displays TDRSS telemetry and commands in real time via X-windows. The system constructs a momentum unload plan which agrees with the preferences of the attitude control specialists and the momentum growth characteristics of the individual spacecraft. During the execution of the plan, the system monitors the progress of the procedure and watches for unexpected problems.

  6. LOADING AND UNLOADING DEVICE

    DOEpatents

    Treshow, M.

    1960-08-16

    A device for loading and unloading fuel rods into and from a reactor tank through an access hole includes parallel links carrying a gripper. These links enable the gripper to go through the access hole and then to be moved laterally from the axis of the access hole to the various locations of the fuel rods in the reactor tank.

  7. NUCLEAR REACTOR UNLOADING APPARATUS

    DOEpatents

    Leverett, M.C.; Howe, J.P.

    1959-01-20

    An unloading device is described for a heterogeneous reactor of the type wherein the fuel elements are in the form of cylindrical slugs and are disposed in horizontal coolant tubes which traverse the reactor core, coolant fluid being circulated through the tubes. The coolant tubes have at least two inwardly protruding ribs from their lower surfaces to support the slugs in spaced relationship to the inside walls of the tubes. The unloading device consists of a ribbon-like extractor member insertable into the coolant tubes in the space between the ribs and adapted to slide under the fuel slugs thereby raising them off of the ribs and forming a slideway for removing them from the reactor. The fuel slugs are ejected by being forced out of the tubes by incoming new fuel slugs or by a push rod insentable through the inlet end of the fuel tubes.

  8. Apparatus for unloading pressurized fluid

    DOEpatents

    Rehberger, Kevin M.

    1994-01-01

    An apparatus for unloading fluid, preferably pressurized gas, from containers in a controlled manner that protects the immediate area from exposure to the container contents. The device consists of an unloading housing, which is enclosed within at least one protective structure, for receiving the dispensed contents of the steel container, and a laser light source, located external to the protective structure, for opening the steel container instantaneously. The neck or stem of the fluid container is placed within the sealed interior environment of the unloading housing. The laser light passes through both the protective structure and the unloading housing to instantaneously pierce a small hole within the stem of the container. Both the protective structure and the unloading housing are specially designed to allow laser light passage without compromising the light's energy level. Also, the unloading housing allows controlled flow of the gas once it has been dispensed from the container. The external light source permits remote operation of the unloading device.

  9. 38. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE FROM THE GEORGE M. CARL.' VIEW LOOKING EAST. (Also see OH-18-14, OH-18-39, and OH-18-40) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  10. 14. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE FROM THE 'GEORGE M. CAR.' VIEW LOOKING EAST. (Also see OH-18-38, OH-18-39, and OH-18-40.) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  11. Apparatus for unloading pressurized fluid

    DOEpatents

    Rehberger, K.M.

    1994-01-04

    An apparatus is described for unloading fluid, preferably pressurized gas, from containers in a controlled manner that protects the immediate area from exposure to the container contents. The device consists of an unloading housing, which is enclosed within at least one protective structure, for receiving the dispensed contents of the steel container, and a laser light source, located external to the protective structure, for opening the steel container instantaneously. The neck or stem of the fluid container is placed within the sealed interior environment of the unloading housing. The laser light passes through both the protective structure and the unloading housing to instantaneously pierce a small hole within the stem of the container. Both the protective structure and the unloading housing are specially designed to allow laser light passage without compromising the light's energy level. Also, the unloading housing allows controlled flow of the gas once it has been dispensed from the container. The external light source permits remote operation of the unloading device. 2 figures.

  12. REACTOR UNLOADING MEANS

    DOEpatents

    Cooper, C.M.

    1957-08-20

    A means for remotely unloading irradiated fuel slugs from a neutronic reactor core and conveying them to a remote storage tank is reported. The means shown is specifically adapted for use with a reactor core wherein the fuel slugs are slidably held in end to end abutting relationship in the horizontal coolant flow tubes, the slugs being spaced from tae internal walls of the tubes to permit continuous circulation of coolant water therethrough. A remotely operated plunger at the charging ends of the tubes is used to push the slugs through the tubes and out the discharge ends into a special slug valve which transfers the slug to a conveying tube leading into a storage tank. Water under pressure is forced through the conveying tube to circulate around the slug to cool it and also to force the slug through the conveving tube into the storage tank. The slug valve and conveying tube are shielded to prevent amy harmful effects caused by the radioactive slug in its travel from the reactor to the storage tank. With the disclosed apparatus, all the slugs in the reactor core can be conveyed to the storage tank shortly after shutdown by remotely located operating personnel.

  13. SYSTEM FOR UNLOADING REACTORS

    DOEpatents

    Rand, A.C. Jr.

    1961-05-01

    An unloading device for individual vertical fuel channels in a nuclear reactor is shown. The channels are arranged in parallel rows and underneath each is a separate supporting block on which the fuel in the channel rests. The blocks are raounted in contiguous rows on an array of parallel pairs of tracks over the bottom of the reactor. Oblong hollows in the blocks form a continuous passageway through the middle of the row of blocks on each pair of tracks. At the end of each passageway is a horizontal grappling rod with a T- or L extension at the end next to the reactor of a length to permit it to pass through the oblong passageway in one position, but when rotated ninety degrees the head will strike one of the longer sides of the oblong hollow of one of the blocks. The grappling rod is actuated by a controllable reciprocating and rotating device which extends it beyond any individual block desired, rotates it and retracts it far enough to permit the fuel in the vertical channel above the block to fall into a handling tank below the reactor.

  14. Tank waste remediation system dangerous waste training plan

    SciTech Connect

    POHTO, R.E.

    1999-05-13

    This document outlines the dangerous waste training program developed and implemented for all Treatment, Storage, and Disposal (TSD) Units operated by Lockheed Martin Hanford Corporation (LMHC) Tank Waste Remediation System (TWRS) in the Hanford 200 East, 200 West and 600 Areas and the <90 Day Accumulation Area at 209E. Operating TSD Units operated by TWRS are: the Double-Shell Tank (DST) System (including 204-AR Waste Transfer Building), the 600 Area Purgewater Storage and the Effluent Treatment Facility. TSD Units undergoing closure are: the Single-Shell Tank (SST) System, 207-A South Retention Basin, and the 216-B-63 Trench.

  15. Hindlimb unloading increases oxidative stress and disrupts antioxidant capacity in skeletal muscle

    NASA Technical Reports Server (NTRS)

    Lawler, John M.; Song, Wook; Demaree, Scott R.; Bloomfield, S. A. (Principal Investigator)

    2003-01-01

    Skeletal muscle disuse with space-flight and ground-based models (e.g., hindlimb unloading) results in dramatic skeletal muscle atrophy and weakness. Pathological conditions that cause muscle wasting (i.e., heart failure, muscular dystrophy, sepsis, COPD, cancer) are characterized by elevated "oxidative stress," where antioxidant defenses are overwhelmed by oxidant production. However, the existence, cellular mechanisms, and ramifications of oxidative stress in skeletal muscle subjected to hindlimb unloading are poorly understood. Thus we examined the effects of hindlimb unloading on hindlimb muscle antioxidant enzymes (e.g., superoxide dismutase, catalase, glutathione peroxidase), nonenzymatic antioxidant scavenging capacity (ASC), total hydroperoxides, and dichlorohydrofluorescein diacetate (DCFH-DA) oxidation, a direct indicator of oxidative stress. Twelve 6 month old Sprague Dawley rats were divided into two groups: 28 d of hindlimb unloading (n = 6) and controls (n = 6). Hindlimb unloading resulted in a small decrease in Mn-superoxide dismutase activity (10.1%) in the soleus muscle, while Cu,Zn-superoxide dismutase increased 71.2%. In contrast, catalase and glutathione peroxidase, antioxidant enzymes that remove hydroperoxides, were significantly reduced in the soleus with hindlimb unloading by 54.5 and 16.1%, respectively. Hindlimb unloading also significantly reduced ASC. Hindlimb unloading increased soleus lipid hydroperoxide levels by 21.6% and hindlimb muscle DCFH-DA oxidation by 162.1%. These results indicate that hindlimb unloading results in a disruption of antioxidant status, elevation of hydroperoxides, and an increase in oxidative stress.

  16. Will 'Unloading' Shoes Help Your Arthritic Knees?

    MedlinePlus

    ... 160406.html Will 'Unloading' Shoes Help Your Arthritic Knees? Study puts specially designed footwear to the test ... 2016 (HealthDay News) -- For reducing pain from arthritic knees, "unloading" shoes don't offer a leg up ...

  17. Efficient Vent Unloading of Air Compressors

    NASA Technical Reports Server (NTRS)

    Muhonen, Alvin J.

    1987-01-01

    Method for unloading one-and two-stage reciprocating air compressors increases energy efficiency and inhibits deterioration of components. In new unloader configuration, compressor vented to atmosphere on downstream side. Method implemented expeditiously as modification of existing systems.

  18. A method for assessment of slope unloading zone based on unloading strain

    NASA Astrophysics Data System (ADS)

    Bao, Han; Wu, Faquan; Xi, Pengcheng

    2016-04-01

    Slope unloading is a process of energy release. During the evolution of slope, unloading deformation appears and unloading zone is formed in shallow slope with rock mass relaxation and extension. In this paper, a new method is proposed to quantify the extent and damage degree of unloading zone according to unloading strain energy which is released in the process of unloading. By using elastic theory and statistical mechanics of rock masses, we establish a relation between accumulative opening displacement of unloading cracks and unloading strain, which is the principle to assess the extent and damage degree of unloading zone. Based on the unloading strain, the degree of unloading zone can be divided into two sub-zones, i.e., strongly unloading zone and slightly unloading zone, and the extent of the two sub-zones can be determined from the accumulative opening displacement curves of cracks. This method is applied to assess the slope unloading zone at a hydropower station dam site in northwest China. Results show that the accumulative opening displacement curves of cracks along adits vary regularly, and the curves can be divided into three parts. The strongly and slightly unloading zones can be recognized from the slope of each part, and their extent is limited by the two inflexions of each curve.

  19. Hindlimb unloading alters ligament healing

    NASA Technical Reports Server (NTRS)

    Provenzano, Paolo P.; Martinez, Daniel A.; Grindeland, Richard E.; Dwyer, Kelley W.; Turner, Joanne; Vailas, Arthur C.; Vanderby, Ray Jr

    2003-01-01

    We investigated the hypothesis that hindlimb unloading inhibits healing in fibrous connective tissue such as ligament. Male rats were assigned to 3- and 7-wk treatment groups with three subgroups each: sham control, ambulatory healing, and hindlimb-suspended healing. Ambulatory and suspended animals underwent surgical rupture of their medial collateral ligaments, whereas sham surgeries were performed on control animals. After 3 or 7 wk, mechanical and/or morphological properties were measured in ligament, muscle, and bone. During mechanical testing, most suspended ligaments failed in the scar region, indicating the greatest impairment was to ligament and not to bone-ligament insertion. Ligament testing revealed significant reductions in maximum force, ultimate stress, elastic modulus, and low-load properties in suspended animals. In addition, femoral mineral density, femoral strength, gastrocnemius mass, and tibialis anterior mass were significantly reduced. Microscopy revealed abnormal scar formation and cell distribution in suspended ligaments with extracellular matrix discontinuities and voids between misaligned, but well-formed, collagen fiber bundles. Hence, stress levels from ambulation appear unnecessary for formation of fiber bundles yet required for collagen to form structurally competent continuous fibers. Results support our hypothesis that hindlimb unloading impairs healing of fibrous connective tissue. In addition, this study provides compelling morphological evidence explaining the altered structure-function relationship in load-deprived healing connective tissue.

  20. Dynamics of oxygen unloading from sickle erythrocytes.

    PubMed

    Makhijani, V B; Cokelet, G R; Clark, A

    1990-10-01

    The objective of this work is to theoretically model oxygen unloading in sickle red cells. This has been done by combining into a single model diffusive transport mechanisms, which have been well-studied for normal red cells, and the hemoglobin polymerization process, which has been previously been studied for deoxyhemoglobin-S solutions and sickle cells in near-equilibrium situations. The resulting model equations allow us to study the important processes of oxygen delivery and polymerization simultaneously. The equations have been solved numerically by a finite-difference technique. The oxygen unloading curve for sickle erythrocytes is biphasic in nature. The rate of unloading depends in a complicated way on (a) the kinetics of hemoglobin S polymerization, (b) the kinetics of hemoglobin deoxygenation, and (c) the diffusive transport of both free oxygen and oxy-hemoglobin. These processes interact. For example, the hemoglobin S polymer interferes with the transport of both free oxygen and unpolymerized oxy-hemoglobin, and this is accounted for in the model by diffusivities which depend on the polymer and solution hemoglobin concentration. Other parameters which influence the interaction of these processes are the concentration of 2,3-diphosphoglycerate and total hemoglobin concentration. By comparing our model predictions for oxygen unloading with simpler predictions based on equilibrium oxygen affinities, we conclude that the relative rate of oxygen unloading of cells with different physical properties cannot be correctly predicted from the equilibrium affinities. To describe the unloading process, a kinetic calculation of the sort we give here is required. PMID:2248988

  1. Dynamics of oxygen unloading from sickle erythrocytes.

    PubMed Central

    Makhijani, V B; Cokelet, G R; Clark, A

    1990-01-01

    The objective of this work is to theoretically model oxygen unloading in sickle red cells. This has been done by combining into a single model diffusive transport mechanisms, which have been well-studied for normal red cells, and the hemoglobin polymerization process, which has been previously been studied for deoxyhemoglobin-S solutions and sickle cells in near-equilibrium situations. The resulting model equations allow us to study the important processes of oxygen delivery and polymerization simultaneously. The equations have been solved numerically by a finite-difference technique. The oxygen unloading curve for sickle erythrocytes is biphasic in nature. The rate of unloading depends in a complicated way on (a) the kinetics of hemoglobin S polymerization, (b) the kinetics of hemoglobin deoxygenation, and (c) the diffusive transport of both free oxygen and oxy-hemoglobin. These processes interact. For example, the hemoglobin S polymer interferes with the transport of both free oxygen and unpolymerized oxy-hemoglobin, and this is accounted for in the model by diffusivities which depend on the polymer and solution hemoglobin concentration. Other parameters which influence the interaction of these processes are the concentration of 2,3-diphosphoglycerate and total hemoglobin concentration. By comparing our model predictions for oxygen unloading with simpler predictions based on equilibrium oxygen affinities, we conclude that the relative rate of oxygen unloading of cells with different physical properties cannot be correctly predicted from the equilibrium affinities. To describe the unloading process, a kinetic calculation of the sort we give here is required. PMID:2248988

  2. Interleukin-2 therapy reverses some immunosuppressive effects of skeletal unloading

    NASA Technical Reports Server (NTRS)

    Armstrong, Jason W.; Balch, Signe; Chapes, Stephen K.

    1994-01-01

    Using antiorthostatic suspension, we characterized hematopoietic changes that may be responsible for the detrimental effect of skeletal unloading on macrophage development. Skeletally unloaded mice had suppressed macrophage development in unloaded and loaded bones, which indicated a systemic effect. Bone marrow cells from unloaded mice secreted less macrophage colony-stimulating factor and interleukin-6 than control mice. Additionally, T-lymphocyte proliferation was reduced after skeletal unloading. We show that polyethylene glycol-interleukin-2 therapy reversed the effects of skeletal unloading on macrophage development and cell proliferation.

  3. Hindlimb unloading rodent model: technical aspects

    NASA Technical Reports Server (NTRS)

    Morey-Holton, Emily R.; Globus, Ruth K.

    2002-01-01

    Since its inception at the National Aeronautics and Space Administration (NASA) Ames Research Center in the mid-1970s, many laboratories around the world have used the rat hindlimb unloading model to simulate weightlessness and to study various aspects of musculoskeletal loading. In this model, the hindlimbs of rodents are elevated to produce a 30 degrees head-down tilt, which results in a cephalad fluid shift and avoids weightbearing by the hindquarters. Although several reviews have described scientific results obtained with this model, this is the first review to focus on the technical aspects of hindlimb unloading. This review includes a history of the technique, a brief comparison with spaceflight data, technical details, extension of the model to mice, and other important technical considerations (e.g., housing, room temperature, unloading angle, the potential need for multiple control groups, age, body weight, the use of the forelimb tissues as internal controls, and when to remove animals from experiments). This paper is intended as a reference for researchers, reviewers of manuscripts, and institutional animal care and use committees. Over 800 references, related to the hindlimb unloading model, can be accessed via the electronic version of this article.

  4. System modeling speeds clamshell unloader delivery

    SciTech Connect

    Schuster, J.W.; Zirkler, A.H.; Duke, G.

    1995-04-01

    This article describes how enhanced dust control concepts and design studies found best method to ensure quick, safe clamshell unloader transport and assembly. A new facility, US Generating Co.`s Logan Generating Station, was built in New Jersey, along the Delaware River and four miles from Chester, Pa. At the outset, concerns arose over possible unusual regulatory issues because the plant`s coal barge unloading system extends into the river where it falls under the jurisdiction of the State of Delaware. However, the project contract with the equipment supplier avoided complications by calling for a turnkey project, including erection, start-up, commissioning and training. The supplier responded by using a modeling technique to ensure environmental compatibility. The contract called for one stationary-clamshell bucket grab unloader, complete with a dust control system, barge haul and barge breasting systems, and auxiliary cranes for handling the barge haul lines. Bucket coal capacity is 10 tons at 50 pounds per cubic foot density. When operating on a 40-second duty cycle, the unloader is rated at 910 tons per hour free digging capacity. Under dry, high dust conditions, the duty cycle is extended to 50 seconds to allow for pause time after the bucket closes and while over the hopper prior to bucket discharge.

  5. CONTEXT VIEW ACROSS ORE YARD AT MODERN SELFUNLOADING SHIP UNLOADING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONTEXT VIEW ACROSS ORE YARD AT MODERN SELF-UNLOADING SHIP UNLOADING IN FRONT OF HULETTS. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  6. Acoustic emission during unloading of elastically stressed magnesium alloy

    NASA Technical Reports Server (NTRS)

    Lee, S. S.; Williams, J. H., Jr.

    1977-01-01

    A magnesium alloy was quasi-statically cycled elastically between zero load and tension. Both loading and unloading stress delays were found, and the unloading stress delay was further studied. An analytical expression was written for the unloading stress delay which is an elastic constitutive parameter. The potential use of these results for the acoustic emission monitoring of elastic stress states is discussed.

  7. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Loading and unloading valves. 179.500-11 Section...-113 and 107A) § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or threaded into the marked end of tank. These valves shall be of...

  8. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Loading and unloading valves. 179.500-11 Section... 107A) § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or threaded into the marked end of tank. These valves shall be of approved type,...

  9. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Loading and unloading valves. 179.500-11 Section... 107A) § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or threaded into the marked end of tank. These valves shall be of approved type,...

  10. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Loading and unloading valves. 179.500-11 Section... 107A) § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or threaded into the marked end of tank. These valves shall be of approved type,...

  11. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Loading and unloading valves. 179.500-11 Section... 107A) § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or threaded into the marked end of tank. These valves shall be of approved type,...

  12. The response of bone to unloading

    NASA Technical Reports Server (NTRS)

    Bikle, D. D.; Halloran, B. P.

    1999-01-01

    Skeletal unloading leads to decreased bone formation and decreased bone mass. Bone resorption is uncoupled from bone formation, contributing to the bone loss. During spaceflight bone is lost principally from the bones most loaded in the 1-g environment, and some redistribution of bone from the lower extremities to the head appears to take place. Although changes in calcitropic hormones have been demonstrated during skeletal unloading (PTH and 1,25(OH)2D decrease), it remains unclear whether such changes account for or are in response to the changes in bone formation and resorption. Bed rest studies with human volunteers and hindlimb elevation studies with rats have provided useful data to help explain the changes in bone formation during spaceflight. These models of skeletal unloading reproduce a number of the conditions associated with microgravity, and the findings from such studies confirm many of the observations made during spaceflight. Determining the mechanism(s) by which loading of bone is sensed and translated into a signal(s) controlling bone formation remains the holy grail in this field. Such investigations couple biophysics to biochemistry to cell and molecular biology. Although studies with cell cultures have revealed biochemical responses to mechanical loads comparable to that seen in intact bone, it seems likely that matrix-cell interactions underlie much of the mechanocoupling. The role for systemic hormones such as PTH, GH, and 1,25(OH)2D compared to locally produced factors such as IGF-I, PTHrP, BMPs, and TGF-beta in modulating the cellular response to load remains unclear. As the mechanism(s) by which bone responds to mechanical load with increased bone formation are further elucidated, applications of this knowledge to other etiologies of osteoporosis are likely to develop. Skeletal unloading provides a perturbation in bone mineral homeostasis that can be used to understand the mechanisms by which bone mineral homeostasis is maintained, with

  13. Self-unloading, reusable, lunar lander project

    NASA Technical Reports Server (NTRS)

    Arseculeratne, Ruwan; Cavazos, Melissa; Euker, John; Ghavidel, Fred; Hinkel, Todd J.; Hitzfelder, John; Leitner, Jesse; Nevik, James; Paynter, Scott; Zolondek, Allen

    1990-01-01

    In the early 21st century, NASA will return to the Moon and establish a permanent base. To achieve this goal safely and economically, B&T Engineering has designed an unmanned, reusable, self-unloading lunar lander. The lander is designed to deliver 15,000 kg payloads from an orbit transfer vehicle (OTV) in a low lunar polar orbit and an altitude of 200 km to any location on the lunar surface.

  14. The temporal response of bone to unloading

    NASA Technical Reports Server (NTRS)

    Globus, R. K.; Bikle, D. D.; Morey-Holton, E.

    1984-01-01

    Rats were suspended by their tails with the forelimbs bearing the weight load to simulate the weightlessness of space flight. Growth in bone mass ceased by 1 week in the hindlimbs and lumbar vertebrae in growing rats, while growth in the forelimbs and cervical vertebrae remained unaffected. The effects of selective skeletal unloading on bone formation during 2 weeks of suspension was investigated using radio iostope incorporation (with Ca-45 and H-3 proline) and histomorphometry (with tetracycline labeling). The results of these studies were confirmed by histomorphometric measurements of bone formation using triple tetracycline labeling. This model of simulated weightlessness results in an initial inhibition of bone formation in the unloaded bones. This temporary cessation of bone formation is followed in the accretion of bone mass, which then resumes at a normal rate by 14 days, despite continued skeletal unloading. This cycle of inhibition and resumption of bone formation has profound implication for understanding bone dynamics durng space flight, immobilization, or bed rest and offers an opportunity to study the hormonal and mechanical factors that regulate bone formation.

  15. Phloem unloading in developing leaves of sugar beet. II. Termination of phloem unloading

    SciTech Connect

    Schmalstig, J.G.; Geiger, D.R.

    1987-01-01

    Phloem unloading in developing leaves of Beta vulgaris L. occurred from successively higher order branches of veins as leaves matured. Phloem unloading was studied in autoradiographs of leaf samples taken at various times during the arrival of a pulse of /sup 14/C-labeled photoassimilate. Extension of mass flow of sieve element contents into leaf vein branches was determined from the high level of radiolabel in veins soon after first arrival of the pulse. Rapid entry, indicative of mass flow through open sieve pores, occurred down to the fourth division of veins in young, importing leaves and to the fifth or terminal branch in importing regions near the zone of transition from sink to source. The rate of unloading decreased with leaf age, as evidenced by the increased time required for the vein-mesophyll demarcation to become obscured. The rate of import per unit leaf area, measures by steady state labeling with /sup 14/CL/sub 2/ also decreased as a leaf matured. The decline in import appeared to result from progressive changes that increased resistance to unloading of sieve elements and eventually terminated phloem unloading.

  16. Skeletal muscle responses to unloading in humans

    NASA Technical Reports Server (NTRS)

    Dudley, G.; Tesch, P.; Hather, B.; Adams, G.; Buchanan, P.

    1992-01-01

    This study examined the effects of unloading on skeletal muscle structure. Method: Eight subjects walked on crutches for six weeks with a 110 cm elevated sole on the right shoe. This removed weight bearing by the left lower limb. Magnetic resonance imaging of both lower limbs and biopsies of the left m. vastus laterallis (VL) were used to study muscle structure. Results: Unloading decreased (P less than 0.05) muscle cross-sectional areas (CSA) of the knee extensors 16 percent. The knee flexors showed about 1/2 of this response (-7 percent, P less than 0.05). The three vasti muscles each showed decreases (P less than 0.05) of about 15 percent. M. rectus femoris did not change. Mean fiber CSA in VL decreased (P less than 0.05) 14 percent with type 2 and type 1 fibers showing reductions of 15 and 11 percent respectively. The ankle extensors showed a 20 percent decrease (P less than 0.05) in CSA. The reduction for the 'fast' m. gastrocnemius was 27 percent compared to the 18 percent decrease for the 'slow' soleus. Summary: The results suggest that decreases in muscle CSA are determined by the relative change in impact loading history because atrophy was (1) greater in extensor than flexor muscles, (2) at least as great in fast as compared to slow muscles or fibers, and (3) not dependent on single or multi-joint function. They also suggest that the atrophic responses to unloading reported for lower mammals are quantitatively but not qualitatively similar to those of humans.

  17. Bone Proteoglycan Changes During Skeletal Unloading

    NASA Technical Reports Server (NTRS)

    Yamauchi, M.; Uzawa, K.; Pornprasertsuk, S.; Arnaud, S.; Grindeland, R.; Grzesik, W.

    1999-01-01

    Skeletal adaptability to mechanical loads is well known since the last century. Disuse osteopenia due to the microgravity environment is one of the major concerns for space travelers. Several studies have indicated that a retardation of the mineralization process and a delay in matrix maturation occur during the space flight. Mineralizing fibrillar type I collagen possesses distinct cross-linking chemistries and their dynamic changes during mineralization correlate well with its function as a mineral organizer. Our previous studies suggested that a certain group of matrix proteoglycans in bone play an inhibitory role in the mineralization process through their interaction with collagen. Based on these studies, we hypothesized that the altered mineralization during spaceflight is due in part to changes in matrix components secreted by cells in response to microgravity. In this study, we employed hindlimb elevation (tail suspension) rat model to study the effects of skeletal unloading on matrix proteoglycans in bone.

  18. Hindlimb unloading: rodent analog for microgravity.

    PubMed

    Globus, Ruth K; Morey-Holton, Emily

    2016-05-15

    The rodent hindlimb unloading (HU) model was developed in the 1980s to make it possible to study mechanisms, responses, and treatments for the adverse consequences of spaceflight. Decades before development of the HU model, weightlessness was predicted to yield deficits in the principal tissues responsible for structure and movement on Earth, primarily muscle and bone. Indeed, results from early spaceflight and HU experiments confirmed the expected sensitivity of the musculoskeletal system to gravity loading. Results from human and animal spaceflight and HU experiments show that nearly all organ systems and tissues studied display some measurable changes, albeit sometimes minor and of uncertain relevance to astronaut health. The focus of this review is to examine key HU results for various organ systems including those related to stress; the immune, cardiovascular, and nervous systems; vision changes; and wound healing. Analysis of the validity of the HU model is important given its potential value for both hypothesis testing and countermeasure development. PMID:26869711

  19. Effect of unloading time on interrupted creep in copper

    SciTech Connect

    Chandler, H.D. . School of Mechanical Engineering)

    1994-06-01

    The effect of unloading time on the interrupted creep behavior of polycrystalline copper specimens was investigated over the temperature range 298--773 K. Up to 553 K, cyclic creep acceleration could be explained in terms of deformation and hardening using a dislocation glide model with recovery during unloading being due to dislocation climb. At higher temperatures, recrystallization effects probably influence behavior.

  20. 27. HULETT ORE UNLOADERS TEMPORARILY IN REPOSE, AS A NEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. HULETT ORE UNLOADERS TEMPORARILY IN REPOSE, AS A NEW SKIP TIES UP AT DOCK. THE UNLOADERS OPERATE ALMOST CONTINUOUSLY DURING THE SHIPPING SEASON, WHICH USUALLY RUNS FROM APRIL UNTIL LATE DECEMBER OR EARLY JANUARY. VIEW HERE IS LOOKING NORTHEAST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  1. 24. REAR ELEVATION, HULETT ORE UNLOADERS. TRACKS CARRYING THE FRONT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. REAR ELEVATION, HULETT ORE UNLOADERS. TRACKS CARRYING THE FRONT END AND REAR LEGS OF THE HULETT UNLOADERS ARE LAID ON THE DOCK AND REAR WALLS, RESPECTIVELY; BOTH WALLS ARE MADE OF REINFORCED CONCRETE SUPPORTED ON CONCRETE PILES. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  2. Grain Unloading of Arsenic Species in Rice

    SciTech Connect

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Charnock, John M.; Feldmann, Joerg; Price, Adam H.; Meharg, Andrew A.

    2010-01-11

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a {+-} stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols.

  3. Right Ventricular Dysfunction During Intensive Pharmacologic Unloading Persists After Mechanical Unloading

    PubMed Central

    Palardy, Maryse; Nohria, Anju; Rivero, Jose; Lakdawala, Neal; Campbell, Patricia; Kato, Mahoto; Griffin, Leslie M.; Smith, Colleen M.; Couper, Gregory S.; Stevenson, Lynne W.; Givertz, Michael M.

    2014-01-01

    Background Right ventricular (RV) dysfunction is associated with adverse outcomes in heart failure (HF). Mechanical unloading should be more effective than pharmacologic therapy to reduce RV afterload and improve RV function. We compared RV size and function after aggressive medical unloading therapy to that achieved in the same patients after 3 months of left ventricular assist device (LVAD) support. Methods and Results We studied twenty patients who underwent isolated LVAD placement (9 pulsatile and 11 axial flow). Echocardiograms were performed after inpatient optimization with diuretic and inotropic therapy and compared to studies done after 3 months of LVAD support. After medical optimization right atrial pressure was 11±5 mm Hg, mean pulmonary artery pressure 36±11 mm Hg, pulmonary capillary wedge pressure 23±9 mm Hg, and cardiac index 2.0±0.6 L/min/m2. Pre-operatively, RV dysfunction was moderate (2.6 ±0.9 on 0-4 scale), RV diameter at the base was 3.1±0.6 cm, and mid-RV was 3.5±0.6 cm. After median LVAD support of 123 days (92-170), RV size and global RV dysfunction (2.6 ±0.9) failed to improve, despite reduced RV afterload. Conclusions RV dysfunction seen on intensive medical therapy persisted after 3 months of LVAD unloading therapy. Selection of candidates for isolated LV support should anticipate persistence of RV dysfunction observed on inotropic therapy. PMID:20206896

  4. Comparison Between Sodium Nitrite & Sodium Hydroxide Spray Accident

    SciTech Connect

    WILLIAMS, J.C.; HEY, B.E.

    2001-11-07

    The purpose of this analysis is to compare the consequences of an 8 molar NaNO2 spray leak to the Tank Farm Final Safety Analysis Report (FSAR) evaluation of sprays of up to 19 molar (50%) NaOH. Four conditions were evaluated. These are: a spray during transfers from a one-inch pipe, a spray resulting from a truck tank Crack, a spray resulting from a truck tank rupture, and a spray in the 204-AR Waste Unloading Facility.

  5. Experimental Investigation of the Mechanical Behavior in Unloading Conditions of Sandstone After High-Temperature Treatment

    NASA Astrophysics Data System (ADS)

    Ding, Qi-Le; Ju, Feng; Mao, Xian-Biao; Ma, Dan; Yu, Bang-Yong; Song, Shuai-Bing

    2016-07-01

    A detailed understanding of damage evolution in rock after high-temperature treatment in unloading conditions is extremely important in underground engineering applications, such as the disposal of highly radioactive nuclear waste, underground coal gasification, and post-disaster reconstruction. We have studied the effects of temperature (200, 400, 600 and 800 °C) and confining pressure (20, 30 and 40 MPa) on the mechanical properties of sandstone. Scanning electron microscopy studies revealed that at temperatures exceeding 400 °C, new cracks formed, and original cracks extended substantially. When the confining pressure was 20 MPa, a temperature increase from 400 to 800 °C resulted in a 75.2% increase in peak strain, a decrease in Young's modulus and peak strength of 62.5 and 35.8 %, respectively, and transition of the failure mechanism from brittleness to ductility. In the triaxial compression tests, the specimen deformed in a more obvious ductile failure manner at higher confining pressure, whereas in the unloading confining pressure experiments, brittle failure was more obvious when the initial confining pressure was higher. We focused on the effects of temperature and initial confining pressure on peak effective loading stress and peak ductile deformation during unloading. At temperatures of >400 °C, the peak ductile deformation increased rapidly with increases in the high temperature treatment or initial confining pressure. The peak effective loading stress decreased sharply with increased temperature but barely changed when the initial confining pressure was varied.

  6. Muscle sarcomere lesions and thrombosis after spaceflight and suspension unloading

    SciTech Connect

    Riley, D.A.; Ellis, S.; Giometti, C.S.; Hoh, J.F.Y.; Ilyina-Kakueva, E.I.; Oganov, V.S.; Slocum, G.R.; Bain, J.L.W.; Sedlak, F.R. )

    1992-08-01

    Extended exposure of humans to spaceflight produces a progressive loss of skeletal muscle strength. This process must be understood to design effective countermeasures. The present investigation examined hindlimb muscles from flight rats killed as close to landing as possible. Spaceflight and tail suspension-hindlimb unloading (unloaded) produced significant decreases in fiber cross-sectional areas of the adductor longus (AL), a slow-twitch antigravity muscle. However, the mean wet weight of the flight AL muscles was near normal, whereas that of the suspension unloaded AL muscles was significantly reduced. Interstitial edema within the flight AL, but not in the unloaded AL, appeared to account for this apparent disagreement.In both conditions, the slow-twitch oxidative fibers atrophied more than the fast-twitch oxidative-glycolytic fibers. Microcirculation was also compromised by spaceflight, such that there was increased formation of thrombi in the postcapillary venules and capillaries.

  7. Looking southeast at coal conveyor leading from the coal unloading ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking southeast at coal conveyor leading from the coal unloading station to the coal elevator. - Wheeling-Pittsburgh Steel Corporation, Allenport Works, Boiler House, Route 88 on West bank of Monongahela River, Allenport, Washington County, PA

  8. CLOSE UP VIEW OF MILL FROM KEKAHA ROAD, WITH UNLOADER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CLOSE UP VIEW OF MILL FROM KEKAHA ROAD, WITH UNLOADER AND CRUSHING MILL WING IN THE FOREGROUND. VIEW FROM THE NORTHEAST - Kekaha Sugar Company, Sugar Mill Building, 8315 Kekaha Road, Kekaha, Kauai County, HI

  9. VIEW OF UNLOADING STATION THAT WAS ADDED IN 1997. SUGAR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF UNLOADING STATION THAT WAS ADDED IN 1997. SUGAR BIN AND MILL IN RIGHT BACKGROUND. VIEW FROM THE NORTHEAST - Kekaha Sugar Company, Sugar Mill Building, 8315 Kekaha Road, Kekaha, Kauai County, HI

  10. CONTEXT VIEW FROM SOUTHERNMOST HULETT, SHOWING UNLOADER AND CLEVELAND BULK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONTEXT VIEW FROM SOUTHERN-MOST HULETT, SHOWING UNLOADER AND CLEVELAND BULK TERMINAL BUILDINGS IN ASSOCIATION. LOOKING SOUTH. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  11. Theseus Nose and Pod Cones Being Unloaded

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Crew members are seen here unloading the nose and pod cones of the Theseus prototype research aircraft at NASA's Dryden Flight Research Center, Edwards, California, in May of 1996. The Theseus aircraft, built and operated by Aurora Flight Sciences Corporation, Manassas, Virginia, was a unique aircraft flown at NASA's Dryden Flight Research Center, Edwards, California, under a cooperative agreement between NASA and Aurora. Dryden hosted the Theseus program, providing hangar space and range safety for flight testing. Aurora Flight Sciences was responsible for the actual flight testing, vehicle flight safety, and operation of the aircraft. The Theseus remotely piloted aircraft flew its maiden flight on May 24, 1996, at Dryden. During its sixth flight on November 12, 1996, Theseus experienced an in-flight structural failure that resulted in the loss of the aircraft. As of the beginning of the year 2000, Aurora had not rebuilt the aircraft. Theseus was built for NASA under an innovative, $4.9 million fixed-price contract by Aurora Flight Sciences Corporation and its partners, West Virginia University, Morgantown, West Virginia, and Fairmont State College, Fairmont, West Virginia. The twin-engine, unpiloted vehicle had a 140-foot wingspan, and was constructed largely of composite materials. Powered by two 80-horsepower, turbocharged piston engines that drove twin 9-foot-diameter propellers, Theseus was designed to fly autonomously at high altitudes, with takeoff and landing under the active control of a ground-based pilot in a ground control station 'cockpit.' With the potential ability to carry 700 pounds of science instruments to altitudes above 60,000 feet for durations of greater than 24 hours, Theseus was intended to support research in areas such as stratospheric ozone depletion and the atmospheric effects of future high-speed civil transport aircraft engines. Instruments carried aboard Theseus also would be able to validate satellite-based global environmental

  12. 49 CFR 173.30 - Loading and unloading of transport vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Loading and unloading of transport vehicles. 173... § 173.30 Loading and unloading of transport vehicles. A person who is subject to the loading and unloading regulations in this subchapter must load or unload hazardous materials into or from a...

  13. 49 CFR 173.30 - Loading and unloading of transport vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Loading and unloading of transport vehicles. 173... § 173.30 Loading and unloading of transport vehicles. A person who is subject to the loading and unloading regulations in this subchapter must load or unload hazardous materials into or from a...

  14. 49 CFR 173.30 - Loading and unloading of transport vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Loading and unloading of transport vehicles. 173... § 173.30 Loading and unloading of transport vehicles. A person who is subject to the loading and unloading regulations in this subchapter must load or unload hazardous materials into or from a...

  15. 49 CFR 173.30 - Loading and unloading of transport vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Loading and unloading of transport vehicles. 173... § 173.30 Loading and unloading of transport vehicles. A person who is subject to the loading and unloading regulations in this subchapter must load or unload hazardous materials into or from a...

  16. 49 CFR 173.30 - Loading and unloading of transport vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Loading and unloading of transport vehicles. 173... § 173.30 Loading and unloading of transport vehicles. A person who is subject to the loading and unloading regulations in this subchapter must load or unload hazardous materials into or from a...

  17. Phloem unloading and cell expansion in pea stems

    SciTech Connect

    Schmalstig, J.G.; Cosgrove, D.J. )

    1989-04-01

    Phloem unloading into elongating stems of dark-grown pea seedlings was greater in regions with higher relative growth rates. Phloem transport was monitored over 1 h by measuring accumulation of radiolabel from {sup 14}C-sucrose added between the cotyledons. The apical hook and plumule and 8 mm of the growing region of an intact plant were sealed in a pressure chamber and the pressure was raised to stop elongation. Phloem unloading was inhibited in the pressurized zone of elongation and accelerated in the apical hook and plumule, with the result that the magnitude of phloem transport into the stem was unchanged. The results demonstrate a coupling between cell expansion and phloem unloading.

  18. Loading-unloading hysteresis loop of randomly rough adhesive contacts

    NASA Astrophysics Data System (ADS)

    Carbone, Giuseppe; Pierro, Elena; Recchia, Giuseppina

    2015-12-01

    We investigate the loading and unloading behavior of soft solids in adhesive contact with randomly rough profiles. The roughness is assumed to be described by a self-affine fractal on a limited range of wave vectors. A spectral method is exploited to generate such randomly rough surfaces. The results are statistically averaged, and the calculated contact area and applied load are shown as a function of the penetration, for loading and unloading conditions. We found that the combination of adhesion forces and roughness leads to a hysteresis loading-unloading loop. This shows that energy can be lost simply as a consequence of roughness and van der Waals forces, as in this case a large number of local energy minima exist and the system may be trapped in metastable states. We numerically quantify the hysteretic loss and assess the influence of the surface statistical properties and the energy of adhesion on the hysteresis process.

  19. Loading-unloading hysteresis loop of randomly rough adhesive contacts.

    PubMed

    Carbone, Giuseppe; Pierro, Elena; Recchia, Giuseppina

    2015-12-01

    We investigate the loading and unloading behavior of soft solids in adhesive contact with randomly rough profiles. The roughness is assumed to be described by a self-affine fractal on a limited range of wave vectors. A spectral method is exploited to generate such randomly rough surfaces. The results are statistically averaged, and the calculated contact area and applied load are shown as a function of the penetration, for loading and unloading conditions. We found that the combination of adhesion forces and roughness leads to a hysteresis loading-unloading loop. This shows that energy can be lost simply as a consequence of roughness and van der Waals forces, as in this case a large number of local energy minima exist and the system may be trapped in metastable states. We numerically quantify the hysteretic loss and assess the influence of the surface statistical properties and the energy of adhesion on the hysteresis process. PMID:26764700

  20. Segment of Challenger's right wing unloaded at KSC Logistics Facility

    NASA Technical Reports Server (NTRS)

    1986-01-01

    a 9'7' x 16' segment of Challenger's right wing is unloaded at the Logistics Facility after being off-loaded from the rescue and salvage ship USS Opportune. It was located and recovered by Navy divers from the Opportune about 12 nautical miles northeast of Cape Canaveral in 70 feet of water.

  1. 2. PHOSPHATE UNLOADING BUILDING. VIEW IS TO THE NORTH. THIS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. PHOSPHATE UNLOADING BUILDING. VIEW IS TO THE NORTH. THIS STRUCTURE WAS RELOCATED TO THE SOUTH OF ITS ORIGINAL SITE IN 1993 FOR USE AS A DECONTAMINATION FACILITY WITHIN THE BUNKER HILL SUPERFUND SITE. - North Idaho Phosphate Company, Silver King Community, Kellogg, Shoshone County, ID

  2. Calf Strength Loss During Mechanical Unloading: Does It Matter?

    NASA Technical Reports Server (NTRS)

    English, K. L.; Mulavara, A.; Bloomberg, J.; Ploutz-Snyder, LL

    2016-01-01

    During the mechanical unloading of spaceflight and its ground-based analogs, muscle mass and muscle strength of the calf are difficult to preserve despite exercise countermeasures that effectively protect these parameters in the thigh. It is unclear what effects these local losses have on balance and whole body function which will be essential for successful performance of demanding tasks during future exploration missions.

  3. Calf Strength Loss During Mechanical Unloading: Does It Matter?

    NASA Technical Reports Server (NTRS)

    English, Kirk L.; Mulavara, Ajitkumar; Bloomberg, Jacob J.; Ploutz-Snyder, Lori L.

    2016-01-01

    During the mechanical unloading of spaceflight and its ground-based analogs, muscle mass and muscle strength of the calf are difficult to preserve despite exercise countermeasures that effectively protect these parameters in the thigh. It is unclear what effects these local losses have on balance and whole body function which will be essential for successful performance of demanding tasks during future exploration missions

  4. 1. GENERAL VIEW OF LOG POND AND BOOM FOR UNLOADING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW OF LOG POND AND BOOM FOR UNLOADING CEDAR LOGS FROM TRUCKS AT LOG DUMP, ADJACENT TO MILL; TRUCKS FORMERLY USED TRIP STAKES, THOUGH FOR SAFER HANDLING OF LOGS WELDED STAKES ARE NOW REQUIRED; AS A RESULT LOADING IS NOW DONE WITH A CRANE - Lester Shingle Mill, 1602 North Eighteenth Street, Sweet Home, Linn County, OR

  5. 49 CFR 174.67 - Tank car unloading.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Administration requirements in 29 CFR 1910.119 and 1910.120) in a location where they are immediately available..., the car must be unloaded through the dome. If the obstruction is frozen liquid and no crack has been... fitted with a cap or plug of appropriate material and construction. (3) The piping extends no more...

  6. 49 CFR 174.67 - Tank car unloading.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Administration requirements in 29 CFR 1910.119 and 1910.120) in a location where they are immediately available..., the car must be unloaded through the dome. If the obstruction is frozen liquid and no crack has been... fitted with a cap or plug of appropriate material and construction. (3) The piping extends no more...

  7. 49 CFR 174.67 - Tank car unloading.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Administration requirements in 29 CFR 1910.119 and 1910.120) in a location where they are immediately available..., the car must be unloaded through the dome. If the obstruction is frozen liquid and no crack has been... fitted with a cap or plug of appropriate material and construction. (3) The piping extends no more...

  8. 49 CFR 174.67 - Tank car unloading.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Administration requirements in 29 CFR 1910.119 and 1910.120) in a location where they are immediately available..., the car must be unloaded through the dome. If the obstruction is frozen liquid and no crack has been... fitted with a cap or plug of appropriate material and construction. (3) The piping extends no more...

  9. 49 CFR 174.67 - Tank car unloading.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Administration requirements in 29 CFR 1910.119 and 1910.120) in a location where they are immediately available..., the car must be unloaded through the dome. If the obstruction is frozen liquid and no crack has been... fitted with a cap or plug of appropriate material and construction. (3) The piping extends no more...

  10. 4. PACK TRAIN WAITING TO BE UNLOADED AT FOOT OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. PACK TRAIN WAITING TO BE UNLOADED AT FOOT OF YAKI TRAIL. APPROXIMATELY TWO-AND-ONE-HALF TONS OF STEEL ON ANIMALS SHOWN. NOTE COIL OF 1-1/2' WIND CABLE IN FOREGROUND. - Kaibab Trail Suspension Bridge, Spanning Colorado River, Grand Canyon, Coconino County, AZ

  11. 29. ORE DOCK, LOOKING WEST; AT WORK UNLOADING THE 'GEORGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. ORE DOCK, LOOKING WEST; AT WORK UNLOADING THE 'GEORGE M. HUMPHREY'S' CARGO OF 25,000. TONS OF ORE. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  12. 18. THREEQUARTER VIEW OF HULETT UNLOADERS, LOOKING NORTHEAST. IF INCOMING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. THREE-QUARTER VIEW OF HULETT UNLOADERS, LOOKING NORTHEAST. IF INCOMING ORE IS NOT TO BE SHIPPED IMMEDIATELY, THE 'LARRYMAN' MOVES HIS CARLOAD OF ORE ALONG THE CANTILEVER AT THE REAR OF THE HULETT AND DEPOSITS IT INTO THE STORAGE YARD. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  13. 36. ORE DOCK, LOOKING WEST. HULETT UNLOADERS AWAIT THE NEXT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. ORE DOCK, LOOKING WEST. HULETT UNLOADERS AWAIT THE NEXT ORE BOAT. BY LATE WINTER, THE ORE STORAGE YARD SEEN AT LEFT WILL BE DEPLETED. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  14. 10. LOOKING DOWN ON TUG AND CAR FLOAT BEING UNLOADED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. LOOKING DOWN ON TUG AND CAR FLOAT BEING UNLOADED AT BRIDGE NO. 11 SHOWING TRACK, LOCKING MECHANISMS, AND MOORING WINCH IN FOREGROUND. LOOKING EAST. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

  15. 40. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also see OH-18-14, OH-18-38, and OH-18-39) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  16. 39. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also see OH-18-14, OH-18-38, and OH-18-40) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  17. Metabolic adaptation of skeletal muscles to gravitational unloading

    NASA Astrophysics Data System (ADS)

    Ohira, Y.; Yasui, W.; Kariya, F.; Wakatsuki, T.; Nakamura, K.; Asakura, T.; Edgerton, V. R.

    Responses of high-energy phosphates and metabolic properties to hindlimb suspension were studied in adult rats. The relative content of phosphocreatine (PCr) in the calf muscles was significantly higher in rats suspended for 10 days than in age-matched cage controls. The Pi/PCr ratio, where Pi is inorganic phosphate, in suspended muscles was less than controls. The absolute weights of soleus and medial gastrocnemius (MG) were approximately 40% less than controls. Although the % fiber distribution in MG was unchanged, the % slow fibers decreased and the % fibers which were classified as both slow and fast was increased in soleus. The activities (per unit weight or protein) of succinate dehydrogenase and lactate dehydrogenase in soleus were unchanged but those of cytochrome oxidase, β-hydroxyacyl CoA dehydrogenase, and citrate synthase were decreased following unloading. None of these enzyme activities in MG changed. However, the total levels of all enzymes in whole muscles decreased by suspension. It is suggested that shift of slow muscle toward fast type by unloading is associated with a decrease in mitochondrial biogenesis. Further, gravitational unloading affected the levels of muscle proteins differently even in the same mitochondrial enzymes. Unloading-related atrophy is prominent in red muscle or slow-twitch fiber 1, 2. Such atrophy is accompanied by a shift of contractile properties toward fast-twitch type 2-9. Further, inhibition of mitochondrial metabolism in these muscles is also reported by some studies 10-14 suggesting a lowered mitochondrial biogenesis, although results from some studies do not necessarily agree 1, 7, 15. However, the precise mechanism responsible for such alterations of muscle properties in response to gravitational unloading is unclear. On the contrary, mitochondrial biogenesis, suggested by mitochondrial enzyme activities and/or mass, is stimulated in muscles with depleted high-energy phosphates by cold exposure 16 and/or by feeding

  18. Vulnerability to dysfunction and muscle injury after unloading

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, L. L.; Tesch, P. A.; Hather, B. M.; Dudley, G. A.

    1996-01-01

    OBJECTIVE: To test whether unloading increases vulnerability to eccentric exercise-induced dysfunction and muscle injury. DESIGN: Before-after trial. SETTING: General community. PATIENTS OR OTHER PARTICIPANTS: Two women and 5 men (73 +/- 3kg [mean +/- SE]) who were active college students but were not trained in lower body resistance exercise volunteered. INTERVENTION: Five weeks of unilateral lower limb suspension (ULLS), which has been shown to decrease strength and size of the unloaded, left, but not load-bearing, right quadriceps femoris muscle group (QF) by 20% and 14%, respectively; performance of 10 sets of ten eccentric actions with each QF immediately after the ULLS strength tests with a load equivalent to 65% of the post-ULLS eccentric 1-repetition maximum. MAIN OUTCOME MEASURE(S): Concentric and eccentric 1-repetition maximum for the left, unloaded and the right, load-bearing QF measured immediately after ULLS and 1,4,7,9, and 11 days later; cross-sectional area and spin-spin relaxation time (T2) of each QF as determined by magnetic resonance imaging and measured the last day of ULLS and 3 days later. RESULTS: The mean load used for eccentric exercise was 23 +/- 2 and 30 +/- 3kg for the left, unloaded and right, load-bearing QF, respectively. The concentric and eccentric 1-repetition maximum for the unloaded and already weakened left QF was further decreased by 18% (p = .000) and 27% (p = .000), respectively, 1 day after eccentric exercise. Strength did not return to post-ULLS levels until 7 days of recovery. The right, load-bearing QF showed a 4% decrease (p = .002) in the eccentric 1-repetition maximum 1 day after eccentric exercise. The left, unloaded QF showed an increase in T2 (p = .002) in 18% of its cross-sectional area 3 days after the eccentric exercise, thus indicating muscle injury. The right, load-bearing QF showed no elevation in T2 (p = .280). CONCLUSION: Unloading increases vulnerability to eccentric exercise-induced dysfunction and muscle

  19. 48 CFR 52.247-15 - Contractor Responsibility for Loading and Unloading.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: Contractor Responsibility for Loading and Unloading (APR 1984) (a)(1) Unless otherwise specified in this contract to cover store-door or inside delivery, the Contractor shall load and unload shipments at...

  20. 48 CFR 52.247-15 - Contractor Responsibility for Loading and Unloading.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: Contractor Responsibility for Loading and Unloading (APR 1984) (a)(1) Unless otherwise specified in this contract to cover store-door or inside delivery, the Contractor shall load and unload shipments at...

  1. 48 CFR 52.247-15 - Contractor Responsibility for Loading and Unloading.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: Contractor Responsibility for Loading and Unloading (APR 1984) (a)(1) Unless otherwise specified in this contract to cover store-door or inside delivery, the Contractor shall load and unload shipments at...

  2. 48 CFR 52.247-15 - Contractor Responsibility for Loading and Unloading.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...: Contractor Responsibility for Loading and Unloading (APR 1984) (a)(1) Unless otherwise specified in this contract to cover store-door or inside delivery, the Contractor shall load and unload shipments at...

  3. 48 CFR 52.247-15 - Contractor Responsibility for Loading and Unloading.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: Contractor Responsibility for Loading and Unloading (APR 1984) (a)(1) Unless otherwise specified in this contract to cover store-door or inside delivery, the Contractor shall load and unload shipments at...

  4. Crystal Plasticity Finite Element Analysis of Loading-Unloading Behaviour in Magnesium Alloy Sheet

    SciTech Connect

    Hama, Takayuki; Fujimoto, Hitoshi; Takuda, Hirohiko

    2010-06-15

    Magnesium alloy sheets exhibit strong inelastic response during unloading. In this study crystal plasticity finite element analysis of loading-unloading behaviour during uniaxial tension in a rolled magnesium alloy sheet was carried out, and the mechanism of this inelastic response was examined in detail in terms of macroscopic and mesoscopic deformations. The unloading behaviour obtained by the simulation was in good agreement with the experiment in terms of variation with stress of instantaneous tangent modulus during unloading. Variations of activities of each family of slip systems during the deformation showed that the activation of basal slip systems is the largest during unloading, and the slip direction during unloading is opposite from during loading. These results indicated that one of the factors of the inelastic behaviour during unloading is the fact that the basal slip systems are easily activated during unloading because of their low strengths.

  5. Interface Control Document between the Double Shell Tanks (DST) System and T Plant

    SciTech Connect

    MAY, T.H.

    1999-11-05

    This Interface Control Document (ICD) describes the interface between the Double-Shell Tank (DST) System and T Plant. T Plant generates waste during decontamination activities. These facilities do not have a direct physical interface since the waste will be moved by tank trailer to the 204-AR waste unloading facility. The purpose of the ICD process is to formalize working agreements between the River Protection Project (WP) DST System and organization/companies internal and external to RPP. This ICD has been developed as part of the requirements basis for design of the DST System to support the Phase I Privatization effort.

  6. Rat limb unloading - Soleus histochemistry, ultrastructure, and electromyography

    NASA Technical Reports Server (NTRS)

    Riley, D. A.; Slocum, G. R.; Bain, J. L. W.; Sedlak, F. R.; Sowa, T. E.

    1990-01-01

    The effects of hindlimb unloading on rat-soleus histochemisty, ultrastructure, and electromyogram (EMG) activity were investigated. It was found that, after 14 days of tail suspension, the area of type I and type IIa muscle fibers decreased by 63 and 47 percent, respectively, mainly due to the degradation of subsarcolemmal mitochondria and myofibrils. After 10 days, 3 percent of type IIa fibers exhibited segmental necrosis. After four days, video monitoring revealed abnormal plantar flexion of the hindfeet, which shortened the soleus working range. The EMG activity shifted from tonic to phasic, and aggregate activity decreased drastically after only seven days. The results indictate that the pathological changes in the soleus resulted from unloaded contractions, reduced use, compromised blood flow, and shortened working length.

  7. Transcriptional regulation of decreased protein synthesis during skeletal muscle unloading

    NASA Technical Reports Server (NTRS)

    Howard, G.; Steffen, J. M.; Geoghegan, T. E.

    1989-01-01

    The regulatory role of transcriptional alterations in unloaded skeletal muscles was investigated by determining levels of total muscle RNA and mRNA fractions in soleus, gastrocnemius, and extensor digitorum longus (EDL) of rats subjected to whole-body suspension for up to 7 days. After 7 days, total RNA and mRNA contents were lower in soleus and gastrocnemius, compared with controls, but the concentrations of both RNAs per g muscle were unaltered. Alpha-actin mRNA (assessed by dot hybridization) was significantly reduced in soleus after 1, 3, and 7 days of suspension and in gastrocnemius after 3 and 7 days, but was unchanged in EDL. Protein synthesis directed by RNA extracted from soleus and EDL indicated marked alteration in mRNAs coding for several small proteins. Results suggest that altered transcription and availability of specific mRNAs contribute significantly to the regulation of protein synthesis during skeletal muscle unloading.

  8. No-dependent signaling pathways in unloaded skeletal muscle

    PubMed Central

    Shenkman, Boris S.; Nemirovskaya, Tatiana L.; Lomonosova, Yulia N.

    2015-01-01

    The main focus of the current review is the nitric oxide (NO)-mediated signaling mechanism in unloaded skeletal. Review of the published data describing muscles during physical activity and inactivity demonstrates that NO is an essential trigger of signaling processes, which leads to structural and metabolic changes of the muscle fibers. The experiments with modulation of NO-synthase (NOS) activity during muscle unloading demonstrate the ability of an activated enzyme to stabilize degradation processes and prevent development of muscle atrophy. Various forms of muscle mechanical activity, i.e., plantar afferent stimulation, resistive exercise and passive chronic stretch increase the content of neural NOS (nNOS) and thus may facilitate an increase in NO production. Recent studies demonstrate that NO-synthase participates in the regulation of protein and energy metabolism in skeletal muscle by fine-tuning and stabilizing complex signaling systems which regulate protein synthesis and degradation in the fibers of inactive muscle. PMID:26582991

  9. Self-unloading, unmanned, reusable lunar lander project

    NASA Technical Reports Server (NTRS)

    Cowan, Kevin; Lewis, Ron; Mislinski, Philip; Rivers, Donna; Smith, Solar; Vasicek, Clifford; Verona, Matt

    1991-01-01

    A payload delivery system will be required to support the buildup and operation of a manned lunar base. In response, a self-unloading, unmanned, reusable lunar lander was conceptually designed. The lander will deliver a 7000 kg payload, with the same dimensions as a space station logistics module, from low lunar orbit to any location on the surface of the moon. The technical aspects of the design is introduced as well as the management structure and project cost.

  10. Effects of hindlimb unloading on neuromuscular development of neonatal rats

    NASA Technical Reports Server (NTRS)

    Huckstorf, B. L.; Slocum, G. R.; Bain, J. L.; Reiser, P. M.; Sedlak, F. R.; Wong-Riley, M. T.; Riley, D. A.

    2000-01-01

    We hypothesized that hindlimb suspension unloading of 8-day-old neonatal rats would disrupt the normal development of muscle fiber types and the motor innervation of the antigravity (weightbearing) soleus muscles but not extensor digitorum longus (EDL) muscles. Five rats were suspended 4.5 h and returned 1.5 h to the dam for nursing on a 24 h cycle for 9 days. To control for isolation from the dam, the remaining five littermates were removed on the same schedule but not suspended. Another litter of 10 rats housed in the same room provided a vivarium control. Fibers were typed by myofibrillar ATPase histochemistry and immunostaining for embryonic, slow, fast IIA and fast IIB isomyosins. The percentage of multiple innervation and the complexity of singly-innervated motor terminal endings were assessed in silver/cholinesterase stained sections. Unique to the soleus, unloading accelerated production of fast IIA myosin, delayed expression of slow myosin and retarded increases in standardized muscle weight and fiber size. Loss of multiple innervation was not delayed. However, fewer than normal motor nerve endings achieved complexity. Suspended rats continued unloaded hindlimb movements. These findings suggest that motor neurons resolve multiple innervation through nerve impulse activity, whereas the postsynaptic element (muscle fiber) controls endplate size, which regulates motor terminal arborization. Unexpectedly, in the EDL of unloaded rats, transition from embryonic to fast myosin expression was retarded. Suspension-related foot drop, which stretches and chronically loads EDL, may have prevented fast fiber differentiation. These results demonstrate that neuromuscular development of both weightbearing and non-weightbearing muscles in rats is dependent upon and modulated by hindlimb loading.

  11. Unloaded Treadmill Training Therapy for Lumbar Disc Herniation Injury

    PubMed Central

    Simpson, Steve; Bettis, Brad; Herbertson, James

    1996-01-01

    The low back region is an area that is very susceptible to injury in athletes. Running is an activity that can be significantly affected by chronic overuse stress. The athlete presented in this case report suffered a herniation of the disc between L-4 and L-5 while training for and racing in a national championship marathon. The athlete was placed on a treatment program of heat, electrical muscle stimulation, and strength and flexibility exercises. The athlete also continued to train by unloaded treadmill training therapy. Unloaded treadmill training therapy produced an effect that reduced stress on injured joints and tissue. This enabled the athlete to maintain fitness while running pain-free on this specialized equipment. The athlete trained twice a week for 16 weeks and training runs ranged from 3 miles to a half-marathon (13.1 miles). Unloaded amounts decreased from 20 to 3 pounds. Training times improved at all distances and were maintained following resumption of normal training. ImagesFig 1.Fig 2.Fig 3. PMID:16558374

  12. Biochemical response to chronic shortening in unloaded soleus muscles

    NASA Technical Reports Server (NTRS)

    Jaspers, S. R.; Fagan, J. M.; Tischler, M. E.

    1985-01-01

    One leg of tail-casted suspended rats was immobilized in a plantar-flexed position to test whether chronic shortening of posterior leg muscles affected the metabolic response to unloading. The immobilized plantaris and gastrocnemius muscles of these animals showed approximately 20 percent loss of muscle mass in contrast to simply a slower growth rate with unloading. Loss of mass of the soleus muscle during suspension was not accentuated by chronic shortening. Although protein degradation in the isolated soleus muscle of the plantar-flexed limb was slightly faster than in the contralateral free limb, this difference was offset by faster synthesis of the myofibrillar protein fraction of the chronically shortened muscle. Total adenine nucleotides were 17 percent lower (P less than 0.005) in the chronically shortened soleus muscle following incubation. Glutamate, glutamine, and alanine metabolism showed little response to chronic shortening. These results suggest that, in the soleus muscle, chronic shortening did not alter significantly the metabolic responses to unloading and reduced activity.

  13. Photoplethysmography system for blood pulsation detection in unloaded artery conditions

    NASA Astrophysics Data System (ADS)

    Grabovskis, A.; Marcinkevics, Z.; Rubenis, O.; Rubins, U.; Lusa, V.

    2012-06-01

    Photoplethysmography (PPG) is an optical method of blood pulsation recording and has been extensively studied for decades. Recently PPG is widely used in the medical equipment for patient monitoring and in laboratories for research and physiological studies. In spite of the technological progress in the field of medical equipment, there are no generally accepted standards for clinical PPG measurements up to date. One of the most important factors affecting PPG waveform is the contact pressure between tissue and PPG probe. The aim of the current study was to develop and evaluate a system for software-assisted PPG signal acquisition from the unloaded artery. Novel PPG waveform derived Optimal Pressure Parameter (OPP) has been proposed as the reliable indicator of unloaded artery condition. We affirm that PPG measurements provided in balanced transmural arterial pressure conditions might serve as a reference for the unification of contact manner optical plethysmography methods. It is a step forward towards the standardization of the PPG methodology, and showed that the maximal value of the OPP, obtained in the particular experimental trial, indicates the optimal PPG probe contact pressure at that moment. Our developed system has been validated in the experimental series and showed the possibility of determining the correct PPG contact pressure value with high repeatability. It is concluded that this system can provide the necessary feedback to perform reliable PPG signal acquisition from the unloaded conduit artery.

  14. The impact of skeletal unloading on bone formation

    NASA Technical Reports Server (NTRS)

    Bikle, Daniel D.; Sakata, Takeshi; Halloran, Bernard P.

    2003-01-01

    Skeletal unloading leads to decreased bone formation and decreased bone mass. Bone resorption is uncoupled from bone formation, contributing to the bone loss. During space flight bone is lost principally from the bones most loaded in the 1 g environment. Determining the mechanism(s) by which loading of bone is sensed and translated into a signal(s) controlling bone formation remains the holy grail in this field. It seems likely that matrix/cell interactions will underlie much of the mechanocoupling. Integrins are a prime mediator of such interactions. The role for systemic hormones such as PTH, GH and 1,25(OH)2D compared to locally produced factors such as IGF-I, PTHrP, BMPs and TGF beta in modulating the cellular response to load remains unclear. Our studies demonstrate that skeletal unloading leads to resistance to the anabolic actions of IGF-I on bone as a result of failure of IGF-I to activate its own signaling pathways. This is associated with a reduction in integrin expression, suggesting crosstalk between these two pathways. As the mechanism(s) by which bone responds to changes in mechanical load with changes in bone formation is further elucidated, applications of this knowledge to other etiologies of osteoporosis are likely to develop. Skeletal unloading provides a perturbation in bone mineral homeostasis that can be used to understand the mechanisms by which bone mineral homeostasis is maintained, and that such understanding will lead to effective treatment for disuse osteoporosis in addition to preventive measures for the bone loss that accompanies space travel.

  15. Skeletal muscle responses to unloading with special reference to man

    NASA Technical Reports Server (NTRS)

    Dudley, G. A.; Hather, B. M.; Buchanan, P.

    1992-01-01

    The limited space flight data suggest that exposure to microgravity decreases muscle strength in humans and muscle mass in lower mammals. Several earth-based models have been used to address the effect of unloading on the human neuromuscular system due to the limited access of biological research to long-term space flight. Bedrest eliminates body weight bearing of both lower limbs. Unilateral lower limb suspension (ULLS), where all ambulatory activity is performed on crutches with an elevated sole on the shoe of one foot, has recently been used to unload one lower limb. The results from studies using these two models support their efficacy. The decrease in strength of m. quadriceps femoris, for example, after four to six weeks of bedrest, ULLS or space flight is 20 to 25 percent. The results from the earth-based studies show that this response can be attributed in part to a decrease in the cross-sectional area of the KE which reflects muscle fiber atrophy. The results from the ground based studies also support the limited flight data and show that reductions in strength are larger in lower than upper limbs and in extensor than flexor muscle groups. They also raise issue with the generally held concept that postural muscle is most affected by unweighting. Slow-twitch fibers in lower limb muscles of mixed fiber type composition and muscle composed mainly of slow-twitch fibers do not preferentially atrophy after bedrest or ULLS. Taken together, the data suggest that unloading causes remarkable adaptations in the neuromuscular system of humans. It should be appreciated, however, that this area of research is in its infancy.

  16. Hypertrophy of chronically unloaded muscle subjected to resistance exercise.

    PubMed

    Tesch, P A; Trieschmann, J T; Ekberg, A

    2004-04-01

    In an effort to simulate the compromised function and atrophy of lower limb muscles experienced by astronauts after spaceflight, 21 men and women age 30-56 yr were subjected to unilateral lower limb unloading for 5 wk. Whereas 10 of these subjects performed unilateral knee extensor resistance exercise (ULRE) two or three times weekly, 11 subjects (UL) refrained from training. The exercise regimen consisted of four sets of seven maximal actions, using an apparatus that offers concentric and eccentric resistance by utilizing the inertia of rotating flywheel(s). Knee extensor muscle strength was measured before and after UL and ULRE, and knee extensor and ankle plantar flexor muscle volumes were determined by means of magnetic resonance imaging. Surface electromyographic activity measured after UL inferred increased muscle use to perform a given motor task. UL induced an 8.8% decrease (P < 0.05) in knee extensor muscle volume. After ULRE and as a result of only approximately 16 min of maximal contractile activity over the 5-wk course, muscle volume increased 7.7% (P < 0.05). Muscle strength decreased 24-32% (P < 0.05) in response to UL. Group ULRE showed maintained (P > 0.05) strength. Ankle plantar flexor muscle volume of the unloaded limb decreased (P < 0.05) in both groups (UL 10.5%; ULRE 11.1%). In neither group did the right weight-bearing limb show any change (P > 0.05) in muscle volume or strength. The results of this study provide evidence that resistance exercise not only may offset muscle atrophy but is in fact capable of promoting marked hypertrophy of chronically unloaded muscle. PMID:14660503

  17. Deoxypyridinoline in the Urine of Rats with Unloaded Hindlimbs

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Navidi, M.; Wren, J.; Holton, Emily M. (Technical Monitor)

    1997-01-01

    The urinary excretion of deoxypyridinoline (U-Dpd), a nonreducible collagen crosslink in bone released by osteoclastic activity, is thought to be an accurate marker of bone resorption. The role of increased resorption in the osteopenia of a space flight model which unloads the hindlimbs by suspending the tail is controversial. To assess skeletal resorption in the model we measured U-Dpd (Pyrilinks-D, Metro Biosystems, Inc.) in serial 24 hour urine specimens collected from 250 a (Y) and 450 a (M) male rats with unloaded hindlimbs for four weeks. Both groups of rats were fed AIN76 diets with calcium restricted to 0.2% in Y and to 0.1 % in M. Blood was obtained after 28 days for parathyroid hormone (PTH), 1,25-dihydroxyvitamin D (1,25-D) and alkaline phosphatase (Alkptase). Basal U-Dpd was higher and more variable in Y than M (475+/-200 vs 67+/-9, nM/mM creatinine, p<.001). Repeated measures ANOVA in Y revealed decreases in U-Dpd, 36% in control (C) and 24% in unloaded (S) rats (p<.005). There was a nadir in YS on the 14th day not observed in YC (p<.05). U-Dpd in MC showed no change, but increased in MS by the 14th day and remained elevated. At the end of the experiment, body weights in both Y and M were less in S than C (337+/-16 vs 306+/-12g and 485+/-10 vs 461+/-6g, p=.002). Bill was inversely related to U-Dpd only in M (r=0.699, p=.024). PTH, similar in C and S in Y (52+/-15 vs 42+/-7pg/ml, NS) and M (68+/-13 vs 61+/-12, NS), was unrelated to U-Dpd. 1,25-D tended toward higher values in YC than YS (197+/-103 vs 119+/-30, NS) and correlated with U-Dpd (0.773, p=.015). Alkptase, 1.3 times higher in Y than M, was similar in C and S at the end of unloading. These findings indicate that bone resorption, as reflected by U-Dpd, is suppressed in young and stimulated in mature rats exposed to a space flight model. U-Dpd reflects reduced growth from the diet change in young control and experimental rats and loss of Bill in mature animals exposed to the space flight model, 2

  18. Effects of ice-cap unloading on shallow magmatic reservoirs

    NASA Astrophysics Data System (ADS)

    Bakker, Richard; Frehner, Marcel; Lupi, Matteo

    2015-04-01

    One of the effects of global warming is the increase of volcanic activity. Glacial melting has been shown to cause visco-elastic relaxation of the upper mantle, which in turn promotes upwelling of magmas through the crust. To date, the effects of ice-cap melting on shallow (i.e., less than 10 km depth) plumbing systems of volcanoes are still not clear. We investigate the pressure changes due to glacial unloading around a magmatic reservoir by combining laboratory and numerical methods. As a case study we focus on Snæfellsjökull, a volcano in Western Iceland whose ice cap is currently melting 1.25 meters (thickness) per year. Our approach is as follows: we obtain representative rock samples from the field, preform tri-axial deformation tests at relevant pressure and temperature (PT) conditions and feed the results into a numerical model in which the stress fields before and after ice cap removal are compared. A suite of deformation experiments were conducted using a Paterson-type tri-axial deformation apparatus. All experiments were performed at a constant strain rate of 10-5 s-1, while varying the PT conditions. We applied confining pressures between 50 and 150 MPa and temperatures between 200 and 1000 ° C. Between 200 and 800 ° C we observe a localized deformation and a slight decrease of the Young's modulus from 41 to 38 GPa. Experiments at 900 and 1000 ° C exhibit macroscopically ductile behavior and a marked reduction of the Young's modulus down to 4 GPa at 1000 ° C. These results are used to construct a numerical finite-element model in which we approximate the volcanic edifice and basement by a 2D axisymmetric half-space. We first calculate the steady-state temperature field in the volcanic system and assign the laboratory-derived temperature-dependent Young's modulus to every element of the model. Then the pressure in the edifice is calculated for two scenarios: with and without ice cap. The comparison between the two scenarios allows us estimate the

  19. Indentation-derived elastic modulus of multilayer thin films: Effect of unloading induced plasticity

    SciTech Connect

    Jamison, Ryan Dale; Shen, Yu -Lin

    2015-08-13

    Nanoindentation is useful for evaluating the mechanical properties, such as elastic modulus, of multilayer thin film materials. A fundamental assumption in the derivation of the elastic modulus from nanoindentation is that the unloading process is purely elastic. In this work, the validity of elastic assumption as it applies to multilayer thin films is studied using the finite element method. The elastic modulus and hardness from the model system are compared to experimental results to show validity of the model. Plastic strain is shown to increase in the multilayer system during the unloading process. Additionally, the indentation-derived modulus of a monolayer material shows no dependence on unloading plasticity while the modulus of the multilayer system is dependent on unloading-induced plasticity. Lastly, the cyclic behavior of the multilayer thin film is studied in relation to the influence of unloading-induced plasticity. Furthermore, it is found that several cycles are required to minimize unloading-induced plasticity.

  20. Caldera collapse unloading volcanoes: the textbook case of Fernandina, Galapagos

    NASA Astrophysics Data System (ADS)

    Corbi, F.; Rivalta, E.; Pinel, V.; Maccaferri, F.; Acocella, V.

    2014-12-01

    Calderas are topographical depressions resulting from the yielding of magma chambers roof after large eruptions or intrusive events. On the outer slope, most calderas display radial fissures and, in limited cases, also circumferential fissures. Despite many hypotheses, the conditions controlling the formation of radial and/or circumferential fissures, and thus the shallow magma transfer within the volcano slopes, are still poorly understood. Here we demonstrate with numerical and analog models that the mass redistribution associated with caldera formation promotes shallow sill-shaped magma chambers and controls the orientation of eruptive fissures. We find that depending on the initial injection depth, dikes will bend or twist about an axis parallel to propagation resulting in circumferential and radial eruptive fissures, respectively. This mechanism is governed by the competition between gravitational unloading pressure and dike overpressure. We apply our results to Fernandina (Galapagos, Ecuador), the best case of caldera with radial and circumferential fissures, showing that the predicted stress field caused by the caldera unloading is consistent with the pattern of eruptive fissures and the dynamics of magma propagation.

  1. Phloem Unloading in Developing Leaves of Sugar Beet 1

    PubMed Central

    Schmalstig, J. Gougler; Geiger, Donald R.

    1985-01-01

    Physiological and transport data are presented in support of a symplastic pathway of phloem unloading in importing leaves of Beta vulgaris L. (`Klein E multigerm'). The sulfhydryl reagent p-chloromercuribenzene sulfonic acid (PCMBS) at concentration of 10 millimolar inhibited uptake of exogenous [14C]sucrose by sink leaf tissue over sucrose concentrations of 0.1 to 5.0 millimolar. Inhibited uptake was 24% of controls. The same PCMBS treatment did not affect import of 14C-label into sink leaves during steady state labeling of a source leaf with 14CO2. Lack of inhibition of import implies that sucrose did not pass through the free space during unloading. A passively transported xenobiotic sugar, l-[14C]glucose, imported by a sink leaf through the phloem, was evenly distributed throughout the leaf as seen by whole-leaf autoradiography. In contrast, l-[14C]glucose supplied to the apoplast through the cut petiole or into a vein of a sink leaf collected mainly in the vicinity of the major veins with little entering the mesophyll. These patterns are best explained by transport through the symplast from phloem to mesophyll. Images Fig. 1 Fig. 3 Fig. 6 PMID:16664377

  2. A Mechanism for the Loading-Unloading Substorm Cycle Missing in MHD Global Magnetospheric Simulation Models

    NASA Technical Reports Server (NTRS)

    Klimas, A. J.; Uritsky, V.; Vassiliadis, D.; Baker, D. N.

    2005-01-01

    Loading and consequent unloading of magnetic flux is an essential element of the substorm cycle in Earth's magnetotail. We are unaware of an available global MHD magnetospheric simulation model that includes a loading- unloading cycle in its behavior. Given the central role that MHD models presently play in the development of our understanding of magnetospheric dynamics, and given the present plans for the central role that these models will play in ongoing space weather prediction programs, it is clear that this failure must be corrected. A 2-dimensional numerical driven current-sheet model has been developed that incorporates an idealized current- driven instability with a resistive MHD system. Under steady loading, the model exhibits a global loading- unloading cycle. The specific mechanism for producing the loading-unloading cycle will be discussed. It will be shown that scale-free avalanching of electromagnetic energy through the model, from loading to unloading, is carried by repetitive bursts of localized reconnection. Each burst leads, somewhat later, to a field configuration that is capable of exciting a reconnection burst again. This process repeats itself in an intermittent manner while the total field energy in the system falls. At the end of an unloading interval, the total field energy is reduced to well below that necessary to initiate the next unloading event and, thus, a loading-unloading cycle results. It will be shown that, in this model, it is the topology of bursty localized reconnection that is responsible for the appearance of the loading-unloading cycle.

  3. Passive stretch reduces calpain activity through nitric oxide pathway in unloaded soleus muscles.

    PubMed

    Xu, Peng-Tao; Li, Quan; Sheng, Juan-Juan; Chang, Hui; Song, Zhen; Yu, Zhi-Bin

    2012-08-01

    Unloading in spaceflight or long-term bed rest induces to pronounced atrophy of anti-gravity skeletal muscles. Passive stretch partially resists unloading-induced atrophy of skeletal muscle, but the mechanism remains elusive. The aims of this study were to investigate the hypotheses that stretch tension might increase protein level of neuronal nitric oxide synthase (nNOS) in unloaded skeletal muscle, and then nNOS-derived NO alleviated atrophy of skeletal muscle by inhibiting calpain activity. The tail-suspended rats were used to unload rat hindlimbs for 2 weeks, at the same time, left soleus muscle was stretched by applying a plaster cast to fix the ankle at 35° dorsiflexion. Stretch partially resisted atrophy and inhibited the decreased protein level and activity of nNOS in unloaded soleus muscles. Unloading increased frequency of calcium sparks and elevated intracellular resting and caffeine-induced Ca(2+) concentration ([Ca(2+)]i) in unloaded soleus muscle fibers. Stretch reduced frequency of calcium sparks and restored intracellular resting and caffeine-induced Ca(2+) concentration to control levels in unloaded soleus muscle fibers. The increased protein level and activity of calpain as well as the higher degradation of desmin induced by unloading were inhibited by stretch in soleus muscles. In conclusion, these results suggest that stretch can preserve the stability of sarcoplasmic reticulum Ca(2+) release channels which prevents the elevated [Ca(2+)]i by means of keeping nNOS activity, and then the enhanced protein level and activity of calpain return to control levels in unloaded soleus muscles. Therefore, stretch can resist in part atrophy of unloaded soleus muscles. PMID:22547201

  4. Calcium balance in mature male rats with unloaded hindlimbs

    NASA Technical Reports Server (NTRS)

    Navidi, Meena; Evans, Juliann; Wolinsky, Ira; Arnaud, Sara B.

    2004-01-01

    BACKGROUND: Calcium balances, regulated by the calcium endocrine system, are negative during spaceflight but have not been reported in flight simulation models using fully mature small animals. METHODS: We conducted two calcium (Ca) balance studies in 6-mo-old male rats exposed to a model that unloads the hindlimbs (HU) for 4 wk. Control (C) and HU rats were fed diets with 0.5% Ca in the first and 0.1% Ca in the second study. Housing in metabolic cages enabled daily food and water intake measurements as well as collections of urine and fecal specimens. At necropsy, blood was obtained for measures of Ca-regulating hormones. RESULTS: Both C and HU rats adjusted to housing and diets with decreases in body weight and negative Ca balances during the first week of each experiment. Thereafter, averages of Ca balances were more negative in the unloaded rats than controls: -8.1 vs. -1.6 mg x d(-1) in rats fed 0.5% (p < 0.05). This difference was not due to urinary Ca excretion since it was lower in HU than C rats (1.27 +/- 0.51 mg x d(-1) vs. 2.35 +/- 0.82 mg x d(-1), p < 0.05). Fecal Ca in HU rats exceeded dietary Ca by 4-7%, Restricting dietary Ca to 0.1% was followed by an increase in serum 1,25-dihydroxyvitamin D (1,25-D) and greater intestinal Ca absorption than in rats fed 0.5% Ca. Ca balances in rats fed 0.1% Ca were also more negative in HU than C rats (-2.4 vs. -0.03 mg x d(-1), p < 0.05). Parathyroid hormone (PTH) was suppressed and 1,25-D increased in HU rats fed 0.5% Ca. C rats fed 0.1% Ca had increased PTH and 1,25-D was the same as in the HU group. CONCLUSION: After adaptation, Ca balances were more negative in mature male rats with unloaded hindlimbs than controls, an effect from increased secretion and loss of endogenous fecal Ca associated with increased 1,25-D in Ca-replete and Ca-restricted rats.

  5. Comparing two devices of suspended treadmill walking by varying body unloading and Froude number.

    PubMed

    Ruckstuhl, Heidi; Kho, Jenniefer; Weed, Matthew; Wilkinson, Miles W; Hargens, Alan R

    2009-11-01

    In rehabilitation, treadmill walking with body weight support is commonly used to reduce loads on lower extremities. (1) However, gait pattern alterations during unloading at constant Froude number are infrequently reported. (2) Furthermore, differences between two common devices for unloading are not well known. Therefore, we investigated two devices; a waist-high chamber with increased pressure called Lower Body Positive Pressure (LBPP), and a harness system (LiteGait), considered a standard system for unloading the lower body. Four gait parameters (cadence, normalized stride length, duty factor, and leg angle at touch down), heart rate, and comfort level were monitored in 12 healthy volunteers. Subjects walked at three body weight (BW) conditions (100%, 66%, and 33% BW) and three Froude numbers (Fr), which refer to a dimensionless speed reflecting slow walking (Fr=0.09), comfortable walking (Fr=0.25), and walk-run transition (Fr=0.5). Absolute treadmill speed was determined using Froude numbers reflecting dynamically similar motions during unloading. We found that (1) the normal gait pattern is altered during unloading at a constant Froude number. In rehabilitation, physical therapists should be aware that normal gait pattern may not need to be maintained during unloaded treadmill walking. (2) Gait parameters were not different when comparing LBPP to harness supported walking. However, heart rate was lower and comfort higher during unloaded LBPP ambulation compared to suspended harness walking. Therefore, suspended LBPP walking may be more appropriate for patients with cardiovascular disease and for conditions at high unloading. PMID:19674901

  6. Alterations of collagen matrix in weight-bearing bones during skeletal unloading

    NASA Technical Reports Server (NTRS)

    Shiiba, M.; Arnaud, S. B.; Tanzawa, H.; Uzawa, K.; Yamauchi, M.

    2001-01-01

    Skeletal unloading induces loss of bone mineral density in weight-bearing bones. The objectives of this study were to characterize the post-translational modifications of collagen of weight-bearing bones subjected to hindlimb unloading for 8 weeks. In unloaded bones, tibiae and femurs, while the overall amino acid composition was essentially identical in the unloaded and control tibiae and femurs, the collagen cross-link profile showed significant differences. Two major reducible cross-links (analyzed as dihydroxylysinonorleucine and hydroxylysinonorleucine) were increased in the unloaded bones. In addition, the ratios of the former to the latter as well as pyridinoline to deoxypyridinoline were significantly decreased in the unloaded bones indicating a difference in the extent of lysine hydroxylation at the cross-linking sites between these two groups. These results indicate that upon skeletal unloading the relative pool of newly synthesized collagen is increased and it is post-translationally altered. The alteration could be associated with impaired osteoblastic differentiation induced by skeletal unloading that results in a mineralization defect.

  7. Alendronate increases skeletal mass of growing rats during unloading by inhibiting resorption of calcified cartilage

    NASA Technical Reports Server (NTRS)

    Bikle, D. D.; Morey-Holton, E. R.; Doty, S. B.; Currier, P. A.; Tanner, S. J.; Halloran, B. P.

    1994-01-01

    Loss of bone mass during periods of skeletal unloading remains an important clinical problem. To determine the extent to which resorption contributes to the relative loss of bone during skeletal unloading of the growing rat and to explore potential means of preventing such bone loss, 0.1 mg P/kg alendronate was administered to rats before unloading of the hindquarters. Skeletal unloading markedly reduced the normal increase in tibial mass and calcium content during the 9 day period of observation, primarily by decreasing bone formation, although bone resorption was also modestly stimulated. Alendronate not only prevented the relative loss of skeletal mass during unloading but led to a dramatic increase in calcified tissue in the proximal tibia compared with the vehicle-treated unloaded or normally loaded controls. Bone formation, however, assessed both by tetracycline labeling and by [3H]proline and 45Ca incorporation, was suppressed by alendronate treatment and further decreased by skeletal unloading. Total osteoclast number increased in alendronate-treated animals, but values were similar to those in controls when corrected for the increased bone area. However, the osteoclasts had poorly developed brush borders and appeared not to engage the bone surface when examined at the ultrastructural level. We conclude that alendronate prevents the relative loss of mineralized tissue in growing rats subjected to skeletal unloading, but it does so primarily by inhibiting the resorption of the primary and secondary spongiosa, leading to altered bone modeling in the metaphysis.

  8. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Venting, loading and unloading valves. 179.300-13..., loading and unloading valves. (a) Valves shall be of approved type, made of metal not subject to rapid deterioration by lading, and shall withstand tank test pressure without leakage. The valves shall be...

  9. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Venting, loading and unloading valves. 179.300-13..., loading and unloading valves. (a) Valves shall be of approved type, made of metal not subject to rapid deterioration by lading, and shall withstand tank test pressure without leakage. The valves shall be...

  10. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Venting, loading and unloading valves. 179.300-13..., loading and unloading valves. (a) Valves shall be of approved type, made of metal not subject to rapid deterioration by lading, and shall withstand tank test pressure without leakage. The valves shall be...

  11. Grain Unloading of Arsenic Species in Rice1[W

    PubMed Central

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Charnock, John M.; Feldmann, Joerg; Price, Adam H.; Meharg, Andrew A.

    2010-01-01

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a ± stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols. PMID:19880610

  12. Accuracy of unloading with the anti-gravity treadmill.

    PubMed

    McNeill, David K P; de Heer, Hendrik D; Bounds, Roger G; Coast, J Richard

    2015-03-01

    Body weight (BW)-supported treadmill training has become increasingly popular in professional sports and rehabilitation. To date, little is known about the accuracy of the lower-body positive pressure treadmill. This study evaluated the accuracy of the BW support reported on the AlterG "Anti-Gravity" Treadmill across the spectrum of unloading, from full BW (100%) to 20% BW. Thirty-one adults (15 men and 16 women) with a mean age of 29.3 years (SD = 10.9), and a mean weight of 66.55 kg (SD = 12.68) were recruited. Participants were weighed outside the machine and then inside at 100-20% BW in 10% increments. Predicted BW, as presented by the AlterG equipment, was compared with measured BW. Significant differences between predicted and measured BW were found at all but 90% through 70% of BW. Differences were small (<5%), except at the extreme ends of the unloading spectrum. At 100% BW, the measured weight was lower than predicted (mean = 93.15%, SD = 1.21, p < 0.001 vs. predicted). At 30 and 20% BW, the measured weight was higher than predicted at 35.75% (SD = 2.89, p < 0.001), and 27.67% (SD = 3.76, p < 0.001), respectively. These findings suggest that there are significant differences between reported and measured BW support on the AlterG Anti-Gravity Treadmill®, with the largest differences (>5%) found at 100% BW and the greatest BW support (30 and 20% BW). These differences may be associated with changes in metabolic demand and maximum speed during walking or running and should be taken into consideration when using these devices for training and research purposes. PMID:25226319

  13. Low-level vibrations maintain the intervertebral disc during unloading

    NASA Astrophysics Data System (ADS)

    Holguin, Nilsson

    Changes in intervertebral disc (IVD) biochemistry, morphology and mechanics have been characterized only incompletely in the rat hindlimb unloading (HU) model. Although exposure to chronic vibrations can be damaging, low-magnitude vibrations can attenuate the geometric changes of the IVD due to altered spinal loading. Here, we tested the hypothesis that low-magnitude, high-frequency vibrations will mitigate the hypotrophy, biochemical degradation and deconditioning of the IVD during HU. When applied as whole-body vibrations through all four paws, Sprague-Dawley rats were subjected to HU and exposed to daily periods (15min/d) of either ambulatory activities (HU+AMB) or whole body vibrations superimposed upon ambulation (HU+WBV; WBV at 45Hz, 0.3g). After 4wks and, compared to age-matched control rats (AC), the lumbar IVD of HU+AMB had a 22% smaller glycosaminoglycans/collagen ratio, 12% smaller posterior IVD height, and 13% smaller cross-sectional area. Compared to HU+AMB rats, the addition of low-level vibratory loading did not significantly alter IVD biochemistry, posterior height, area, or volume, but directionally altered IVD geometry. When subjected to upright vibrations through the hindpaws, rats were HU for 4wks. A subset of HU rats stood in an upright posture on a vertically oscillating plate (0.2g) at 45- or 90-Hz (HU+45 or HU+90). After 4wks, regardless of sham (HU+SC) loading (HU+/-SC) and, compared to AC, IVD of HU+/-SC had 10% less height, 39% smaller nucleus pulposus area, less glycosaminoglycans in the nucleus pulposus (21%), anterior annulus fibrosus (16%) and posterior annulus fibrosus (19%), 76% less tension-compression neutral zone (NZ) modulus, 26% greater compressive modulus, 25% greater initial elastic damping modulus, 26% less torsional NZ stiffness, no difference in collagen content and a weaker relationship between tension-compression NZ modulus and posterior height change. Exogenously introduced oscillations maintained the morphology

  14. Methane emissions from process equipment at natural gas production sites in the United States: liquid unloadings.

    PubMed

    Allen, David T; Sullivan, David W; Zavala-Araiza, Daniel; Pacsi, Adam P; Harrison, Matthew; Keen, Kindal; Fraser, Matthew P; Daniel Hill, A; Lamb, Brian K; Sawyer, Robert F; Seinfeld, John H

    2015-01-01

    Methane emissions from liquid unloadings were measured at 107 wells in natural gas production regions throughout the United States. Liquid unloadings clear wells of accumulated liquids to increase production, employing a variety of liquid lifting mechanisms. In this work, wells with and without plunger lifts were sampled. Most wells without plunger lifts unload less than 10 times per year with emissions averaging 21,000-35,000 scf methane (0.4-0.7 Mg) per event (95% confidence limits of 10,000-50,000 scf/event). For wells with plunger lifts, emissions averaged 1000-10,000 scf methane (0.02-0.2 Mg) per event (95% confidence limits of 500-12,000 scf/event). Some wells with plunger lifts are automatically triggered and unload thousands of times per year and these wells account for the majority of the emissions from all wells with liquid unloadings. If the data collected in this work are assumed to be representative of national populations, the data suggest that the central estimate of emissions from unloadings (270 Gg/yr, 95% confidence range of 190-400 Gg) are within a few percent of the emissions estimated in the EPA 2012 Greenhouse Gas National Emission Inventory (released in 2014), with emissions dominated by wells with high frequencies of unloadings. PMID:25488307

  15. The hindlimb unloading rat model: literature overview, technique update and comparison with space flight data

    NASA Technical Reports Server (NTRS)

    Morey-Holton, Emily; Globus, Ruth K.; Kaplansky, Alexander; Durnova, Galina

    2005-01-01

    The hindlimb unloading rodent model is used extensively to study the response of many physiological systems to certain aspects of space flight, as well as to disuse and recovery from disuse for Earth benefits. This chapter describes the evolution of hindlimb unloading, and is divided into three sections. The first section examines the characteristics of 1064 articles using or reviewing the hindlimb unloading model, published between 1976 and April 1, 2004. The characteristics include number of publications, journals, countries, major physiological systems, method modifications, species, gender, genetic strains and ages of rodents, experiment duration, and countermeasures. The second section provides a comparison of results between space flown and hindlimb unloading animals from the 14-day Cosmos 2044 mission. The final section describes modifications to hindlimb unloading required by different experimental paradigms and a method to protect the tail harness for long duration studies. Hindlimb unloading in rodents has enabled improved understanding of the responses of the musculoskeletal, cardiovascular, immune, renal, neural, metabolic, and reproductive systems to unloading and/or to reloading on Earth with implications for both long-duration human space flight and disuse on Earth.

  16. Skeletal unloading induces selective resistance to the anabolic actions of growth hormone on bone

    NASA Technical Reports Server (NTRS)

    Halloran, B. P.; Bikle, D. D.; Harris, J.; Autry, C. P.; Currier, P. A.; Tanner, S.; Patterson-Buckendahl, P.; Morey-Holton, E.

    1995-01-01

    Loss of skeletal weight bearing or physical unloading of bone in the growing animal inhibits bone formation and induces a bone mineral deficit. To determine whether the inhibition of bone formation induced by skeletal unloading in the growing animal is a consequence of diminished sensitivity to growth hormone (GH) we studied the effects of skeletal unloading in young hypophysectomized rats treated with GH (0, 50, 500 micrograms/100 g body weight/day). Skeletal unloading reduced serum osteocalcin, impaired uptake of 3H-proline into bone, decreased proximal tibial mass, and diminished periosteal bone formation at the tibiofibular junction. When compared with animals receiving excipient alone, GH administration increased bone mass in all animals. The responses in serum osteocalcin, uptake of 3H-proline and 45Ca into the proximal tibia, and proximal tibial mass in non-weight bearing animals were equal to those in weight bearing animals. The responses in trabecular bone volume in the proximal tibia and bone formation at the tibiofibular junction to GH, however, were reduced significantly by skeletal unloading. Bone unloading prevented completely the increase in metaphyseal trabecular bone normally induced by GH and severely dampened the stimulatory effect (158% vs. 313%, p < 0.002) of GH on periosteal bone formation. These results suggest that while GH can stimulate the overall accumulation of bone mineral in both weight bearing and non-weight bearing animals, skeletal unloading selectively impairs the response of trabecular bone and periosteal bone formation to the anabolic actions of GH.

  17. Contractile reserve and calcium regulation are depressed in myocytes from chronically unloaded hearts

    NASA Technical Reports Server (NTRS)

    Ito, Kenta; Nakayama, Masaharu; Hasan, Faisal; Yan, Xinhua; Schneider, Michael D.; Lorell, Beverly H.

    2003-01-01

    BACKGROUND: Chronic cardiac unloading of the normal heart results in the reduction of left ventricular (LV) mass, but effects on myocyte contractile function are not known. METHODS AND RESULTS: Cardiac unloading and reduction in LV mass were induced by heterotopic heart transplantation to the abdominal aorta in isogenic rats. Contractility and [Ca(2+)](i) regulation in LV myocytes were studied at both 2 and 5 weeks after transplantation. Native in situ hearts from recipient animals were used as the controls for all experiments. Contractile function indices in myocytes from 2-week unloaded and native (control) hearts were similar under baseline conditions (0.5 Hz, 1.2 mmol/L [Ca(2+)](o), and 36 degrees C) and in response to stimulation with high [Ca(2+)](o) (range 2.5 to 4.0 mmol/L). In myocytes from 5-week unloaded hearts, there were no differences in fractional cell shortening and peak-systolic [Ca(2+)](i) at baseline; however, time to 50% relengthening and time to 50% decline in [Ca(2+)](i) were prolonged compared with controls. Severe defects in fractional cell shortening and peak-systolic [Ca(2+)](i) were elicited in myocytes from 5-week unloaded hearts in response to high [Ca(2+)](o). However, there were no differences in the contractile response to isoproterenol between myocytes from unloaded and native hearts. In 5-week unloaded hearts, but not in 2-week unloaded hearts, LV protein levels of phospholamban were increased (345% of native heart values). Protein levels of sarcoplasmic reticulum Ca(2+) ATPase and the Na(+)/Ca(2+) exchanger were not changed. CONCLUSIONS: Chronic unloading of the normal heart caused a time-dependent depression of myocyte contractile function, suggesting the potential for impaired performance in states associated with prolonged cardiac atrophy.

  18. Muscle regeneration during hindlimb unloading results in a reduction in muscle size after reloading

    NASA Technical Reports Server (NTRS)

    Mozdziak, P. E.; Pulvermacher, P. M.; Schultz, E.

    2001-01-01

    The hindlimb-unloading model was used to study the ability of muscle injured in a weightless environment to recover after reloading. Satellite cell mitotic activity and DNA unit size were determined in injured and intact soleus muscles from hindlimb-unloaded and age-matched weight-bearing rats at the conclusion of 28 days of hindlimb unloading, 2 wk after reloading, and 9 wk after reloading. The body weights of hindlimb-unloaded rats were significantly (P < 0.05) less than those of weight-bearing rats at the conclusion of hindlimb unloading, but they were the same (P > 0.05) as those of weight-bearing rats 2 and 9 wk after reloading. The soleus muscle weight, soleus muscle weight-to-body weight ratio, myofiber diameter, number of nuclei per millimeter, and DNA unit size were significantly (P < 0.05) smaller for the injured soleus muscles from hindlimb-unloaded rats than for the soleus muscles from weight-bearing rats at each recovery time. Satellite cell mitotic activity was significantly (P < 0.05) higher in the injured soleus muscles from hindlimb-unloaded rats than from weight-bearing rats 2 wk after reloading, but it was the same (P > 0.05) as in the injured soleus muscles from weight-bearing rats 9 wk after reloading. The injured soleus muscles from hindlimb-unloaded rats failed to achieve weight-bearing muscle size 9 wk after reloading, because incomplete compensation for the decrease in myonuclear accretion and DNA unit size expansion occurred during the unloading period.

  19. Project UM-HAUL (UnManned Heavy pAyload Unloader and Lander): The design of a reusable lunar lander with an independent cargo unloader

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Project UM-Haul is the preliminary design of a reusable lunar transportation vehicle that travels between a lunar parking orbit and the lunar surface. This vehicle is an indispensible link in the overall task of establishing a lunar base as defined by the NASA Space Exploration Initiative. The response to this need consists of two independent vehicles: a lander and an unloader. The system can navigate and unload itself with a minimum amount of human intervention. The design addresses structural analysis, propulsion, power, controls, communications, payload handling and orbital operations. The Lander has the capacity to decend from low lunar orbit (LLO) to the lunar surface carrying a 7000 kg payload, plus the unloader, plus propellant for ascent to LLO. The Lander employs the Unloader by way of a motorized ramp. The Unloader is a terrain vehicle capable of carrying cargoes of 8,500 kg mass and employs a lift system to lower payloads to the ground. The system can perform ten missions before requiring major servicing.

  20. Anodisation Increases Integration of Unloaded Titanium Implants in Sheep Mandible

    PubMed Central

    Duncan, Warwick J.; Lee, Min-Ho; Bae, Tae-Sung; Lee, Sook-Jeong; Gay, Jennifer; Loch, Carolina

    2015-01-01

    Spark discharge anodic oxidation forms porous TiO2 films on titanium implant surfaces. This increases surface roughness and concentration of calcium and phosphate ions and may enhance early osseointegration. To test this, forty 3.75 mm × 13 mm titanium implants (Megagen, Korea) were placed into healed mandibular postextraction ridges of 10 sheep. There were 10 implants per group: RBM surface (control), RBM + anodised, RBM + anodised + fluoride, and titanium alloy + anodised surface. Resonant frequency analysis (RFA) was measured in implant stability quotient (ISQ) at surgery and at sacrifice after 1-month unloaded healing. Mean bone-implant contact (% BIC) was measured in undemineralised ground sections for the best three consecutive threads. One of 40 implants showed evidence of failure. RFA differed between groups at surgery but not after 1 month. RFA values increased nonsignificantly for all implants after 1 month, except for controls. There was a marked difference in BIC after 1-month healing, with higher values for alloy implants, followed by anodised + fluoride and anodised implants. Anodisation increased early osseointegration of rough-surfaced implants by 50–80%. RFA testing lacked sufficient resolution to detect this improvement. Whether this gain in early bone-implant contact is clinically significant is the subject of future experiments. PMID:26436099

  1. Phloem unloading in developing leaves of sugar beet

    SciTech Connect

    Schmalstig, J.G.

    1985-01-01

    Physiological and transport data support a symplastic pathway for phloem unloading in developing leaves of sugar beet (Beta vulgaris L. Klein E, multigerm). The sulfhydryl inhibitor parachloromercuribenzene sulfonic acid (PCMBS) inhibited uptake of (/sup 14/C)-sucrose added to the free space of developing leaves, but did not affect import of (/sup 14/C)-sucrose during steady-state /sup 14/CO/sub 2/ labeling of a source leaf. The passively-transported xenobiotic sugar, (/sup 14/C)-L-glucose did not readily enter mesophyll cells when supplied through the cut end of the petiole of a sink leaf as determined by whole leaf autoradiography. In contrast, (/sup 14/C)-L-glucose translocated through the phloem from a mature leaf, rapidly entered mesophyll cells, and was evenly distributed between mesophyll and veins. Autoradiographs of developing leaves following a pulse of /sup 14/CO/sub 2/ to a source leaf revealed rapid passage of phloem translocated into progressively higher order veins as the leaf developed. Entry into V order veins occurred during the last stage of import through the phloem. Import into developing leaves was inhibited by glyphosate (N-phosphomethylglycine), a herbicide which inhibits the aromatic amino acid pathway and hence protein synthesis. Glyphosate also stopped net starch accumulation in sprayed mature leaves, but did not affect export of carbon from treated leaves during the time period that import into developed leaves was inhibited.

  2. 77. Neg. No. F65A, Apr 13, 1930, INTERIORASSEMBLY BUILDING, UNLOADING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    77. Neg. No. F-65A, Apr 13, 1930, INTERIOR-ASSEMBLY BUILDING, UNLOADING THE ENAMEL OVEN - Ford Motor Company Long Beach Assembly Plant, Assembly Building, 700 Henry Ford Avenue, Long Beach, Los Angeles County, CA

  3. High-energy proton irradiation of C57Bl6 mice under hindlimb unloading

    NASA Astrophysics Data System (ADS)

    Mendonca, Marc; Todd, Paul; Orschell, Christie; Chin-Sinex, Helen; Farr, Jonathan; Klein, Susan; Sokol, Paul

    2012-07-01

    Solar proton events (SPEs) pose substantial risk for crewmembers on deep space missions. It has been shown that low gravity and ionizing radiation both produce transient anemia and immunodeficiencies. We utilized the C57Bl/6 based hindlimb suspension model to investigate the consequences of hindlimb-unloading induced immune suppression on the sensitivity to whole body irradiation with modulated 208 MeV protons. Eight-week old C57Bl/6 female mice were conditioned by hindlimb-unloading. Serial CBC and hematocrit assays by HEMAVET were accumulated for the hindlimb-unloaded mice and parallel control animals subjected to identical conditions without unloading. One week of hindlimb-unloading resulted in a persistent, statistically significant 10% reduction in RBC count and a persistent, statistically significant 35% drop in lymphocyte count. This inhibition is consistent with published observations of low Earth orbit flown mice and with crewmember blood analyses. In our experiments the cell count suppression was sustained for the entire six-week period of observation and persisted for at least 7 days beyond the period of active hindlimb-unloading. C57Bl/6 mice were also irradiated with 208 MeV Spread Out Bragg Peak (SOBP) protons at the Midwest Proton Radiotherapy Institute at the Indiana University Cyclotron Facility. We found that at 8.5 Gy hindlimb-unloaded mice were significantly more radiation sensitive with 35 lethalities out of 51 mice versus 15 out of 45 control (non-suspended) mice within 30 days of receiving 8.5 Gy of SOBP protons (p =0.001). Both control and hindlimb-unloaded stocktickerCBC analyses of 8.5 Gy proton irradiated and control mice by HEMAVET demonstrated severe reductions in WBC counts (Lymphocytes and PMNs) by day 2 post-irradiation, followed a week to ten days later by reductions in platelets, and then reductions in RBCs about 2 weeks post-irradiation. Recovery of all blood components commenced by three weeks post-irradiation. CBC analyses of 8

  4. Hindlimb unloading of growing rats: a model for predicting skeletal changes during space flight

    NASA Technical Reports Server (NTRS)

    Morey-Holton, E. R.; Globus, R. K.

    1998-01-01

    A model that uses hindlimb unloading of rats was developed to study the consequences of skeletal unloading and reloading as occurs during and following space flight. Studies using the model were initiated two decades ago and further developed at National Aeronautics and Space Administration (NASA)-Ames Research Center. The model mimics some aspects of exposure to microgravity by removing weightbearing loads from the hindquarters and producing a cephalic fluid shift. Unlike space flight, the forelimbs remain loaded in the model, providing a useful internal control to distinguish between the local and systemic effects of hindlimb unloading. Rats that are hindlimb unloaded by tail traction gain weight at the same rate as pairfed controls, and glucocorticoid levels are not different from controls, suggesting that systemic stress is minimal. Unloaded bones display reductions in cancellous osteoblast number, cancellous mineral apposition rate, trabecular bone volume, cortical periosteal mineralization rate, total bone mass, calcium content, and maturation of bone mineral relative to controls. Subsequent studies reveal that these changes also occur in rats exposed to space flight. In hindlimb unloaded rats, bone formation rates and masses of unloaded bones decline relative to controls, while loaded bones do not change despite a transient reduction in serum 1,25-dihydroxyvitamin D (1,25D) concentrations. Studies using the model to evaluate potential countermeasures show that 1,25D, growth hormone, dietary calcium, alendronate, and muscle stimulation modify, but do not completely correct, the suppression of bone growth caused by unloading, whereas continuous infusion of transforming growth factor-beta2 or insulin-like growth factor-1 appears to protect against some of the bone changes caused by unloading. These results emphasize the importance of local as opposed to systemic factors in the skeletal response to unloading, and reveal the pivotal role that osteoblasts play in

  5. Decreased Estrogen May Contribute to Osteopenia in Unloaded Bones

    NASA Technical Reports Server (NTRS)

    Tou, Janet; Arnaud, Sara; Grindeland, Richard; Wade, Charles

    2004-01-01

    Progressive loss of weight-bearing bone in astronauts is one of the most serious impediments to long-duration spaceflight. Estrogen deficiency in women is an established factor in bone loss. Reduced sex hormone levels have been reported in male astronauts, but no data is available regarding spaceflight effects on female sex hormones. The objective of our study was to determine the role of estrogen in disuse osteopenia. The NASA developed hindlimb suspension (HLS) model was used to simulate the unloading disuse of weight-bearing bones experienced in space. Female Sprague-Dawley rats (age 77d; n = 20/group) were HLS or kept ambulatory (AMB) for 38 d and endocrine and bone indices determined. HLS of rats resulted in lower (p less than 0.01) bone mass (9%0), bone mineral content (BMC 13%) and mechanical strength (28%) compared to AMB animals. Plasma estradiol (E2) was lower (p = 0.03) in HLS (10.1 +/- 1.4 pg/ml) compared to AMB rats (16.7 +/- 2.6 pg/ml). E2 was positively correlated to BMC r(sup 2) = 0.67 and mechanical strength r(sup 2) = 0.61. These results suggest that reduced E2 plays a role in disuse osteopenia induced by HLS. Plasma or pituitary lutenizing hormone (LH) and follicle stimulating hormone (FSH) levels were not different in HLS versus AMB rats. However, pituitary LH was correlated to E2 (r(sup 2) = 0.57), suggesting changes in E2 were exerted at the level of the hypothalamus-pituitary axis. Understanding the role of estrogen in disuse osteopenia is necessary to the development of efficacious therapies for female astronauts, bed rest patients and the increasing number of individuals in our sedentary population suffering bone loss.

  6. Gravitational unloading effects on muscle fiber size, phenotype and myonuclear number

    NASA Technical Reports Server (NTRS)

    Ohira, Y.; Yoshinaga, T.; Nomura, T.; Kawano, F.; Ishihara, A.; Nonaka, I.; Roy, R. R.; Edgerton, V. R.

    2002-01-01

    The effects of gravitational unloading with or without intact neural activity and/or tension development on myosin heavy chain (MHC) composition, cross-sectional area (CSA), number of myonuclei, and myonuclear domain (cytoplasmic volume per myonucleus ratio) in single fibers of both slow and fast muscles of rat hindlimbs are reviewed briefly. The atrophic response to unloading is generally graded as follows: slow extensors > fast extensors > fast flexors. Reduction of CSA is usually greater in the most predominant fiber type of that muscle. The percentage of fibers expressing fast MHC isoforms increases in unloaded slow but not fast muscles. Myonuclear number per mm of fiber length and myonuclear domain is decreased in the fibers of the unloaded predominantly slow soleus muscle, but not in the predominantly fast plantaris. Decreases in myonuclear number and domain, however, are observed in plantaris fibers when tenotomy, denervation, or both are combined with hindlimb unloading. All of these results are consistent with the view that a major factor for fiber atrophy is an inhibition or reduction of loading of the hindlimbs. These data also indicate that predominantly slow muscles are more responsive to unloading than predominantly fast muscles. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  7. Increased response to insulin of glucose metabolism in the 6-day unloaded rat soleus muscle

    NASA Technical Reports Server (NTRS)

    Henriksen, Erik J.; Tischler, Marc E.; Johnson, David G.

    1986-01-01

    Hind leg muscles of female rats were unloaded by tail cast suspension for 6 days. In the fresh-frozen unloaded soleus, the significantly greater concentration of glycogen correlated with a lower activity ratio of glycogen phosphorylase (p less than 0.02). The activity ratio of glycogen synthase also was lower (p less than 0.001), possibly due to the higher concentration of glycogen. In isolated unloaded soleus, insulin (0.1 milliunit/ml) increased the oxidation of D(U-C-14) glucose, release of lactate and pyruvate, incorporation of D-(U-C-14) glucose into glycogen, and the concentration of glucose 6-phosphate more (p less than 0.05) than in the weight-bearing soleus. At physiological doses of insulin, the percent of maximal uptake of 2-deoxy-D-(1,2-H-3) glucose/muscle also was greater in the unloaded soleus. Unloading of the soleus increased, by 50 percent the concentration of insuling receptors, due to no decrease in total receptor number during muscle atrophy. This increase may account for the greater response of glucose metabolism to insulin in this muscle. The extensor digitorum longus, which generally shows little response to unloading, displayed no differential response of glucose metabolism to insulin.

  8. Regional responsiveness of the tibia to intermittent administration of parathyroid hormone as affected by skeletal unloading

    NASA Technical Reports Server (NTRS)

    Halloran, B. P.; Bikle, D. D.; Harris, J.; Tanner, S.; Curren, T.; Morey-Holton, E.

    1997-01-01

    To determine whether the acute inhibition of bone formation and deficit in bone mineral induced by skeletal unloading can be prevented, we studied the effects of intermittent parathyroid hormone (PTH) administration (8 micrograms/100 g/day) on growing rats submitted to 8 days of skeletal unloading. Loss of weight bearing decreased periosteal bone formation by 34 and 51% at the tibiofibular junction and tibial midshaft, respectively, and reduced the normal gain in tibial mass by 35%. Treatment with PTH of normally loaded and unloaded animals increased mRNA for osteocalcin (+58 and +148%, respectively), cancellous bone volume in the proximal tibia (+41 and +42%, respectively), and bone formation at the tibiofibular junction (+27 and +27%, respectively). Formation was also stimulated at the midshaft in unloaded (+47%, p < 0.05), but not loaded animals (-3%, NS). Although cancellous bone volume was preserved in PTH-treated, unloaded animals, PTH did not restore periosteal bone formation to normal nor prevent the deficit in overall tibial mass induced by unloading. We conclude that the effects of PTH on bone formation are region specific and load dependent. PTH can prevent the decrease in cancellous bone volume and reduce the decrement in cortical bone formation induced by loss of weight bearing.

  9. Indentation-derived elastic modulus of multilayer thin films: Effect of unloading induced plasticity

    DOE PAGESBeta

    Jamison, Ryan Dale; Shen, Yu -Lin

    2015-08-13

    Nanoindentation is useful for evaluating the mechanical properties, such as elastic modulus, of multilayer thin film materials. A fundamental assumption in the derivation of the elastic modulus from nanoindentation is that the unloading process is purely elastic. In this work, the validity of elastic assumption as it applies to multilayer thin films is studied using the finite element method. The elastic modulus and hardness from the model system are compared to experimental results to show validity of the model. Plastic strain is shown to increase in the multilayer system during the unloading process. Additionally, the indentation-derived modulus of a monolayermore » material shows no dependence on unloading plasticity while the modulus of the multilayer system is dependent on unloading-induced plasticity. Lastly, the cyclic behavior of the multilayer thin film is studied in relation to the influence of unloading-induced plasticity. Furthermore, it is found that several cycles are required to minimize unloading-induced plasticity.« less

  10. Increased susceptibility to Pseudomonas aeruginosa infection under hindlimb-unloading conditions

    NASA Technical Reports Server (NTRS)

    Aviles, Hernan; Belay, Tesfaye; Fountain, Kimberly; Vance, Monique; Sonnenfeld, Gerald

    2003-01-01

    It has been reported that spaceflight conditions alter the immune system and resistance to infection [Belay T, Aviles H, Vance M, Fountain K, and Sonnenfeld G. J Allergy Clin Immunol 170: 262-268, 2002; Hankins WR and Ziegelschmid JF. In: Biomedical Results of Apollo. Washington, DC: NASA, 1975, p. 43-81. (NASA Spec. Rep. SP-368)]. Ground-based models, including the hindlimb-unloading model, have become important tools for increasing understanding of how spaceflight conditions can influence physiology. The objective of the present study was to determine the effect of hindlimb unloading on the susceptibility of mice to Pseudomonas aeruginosa infection. Hindlimb-unloaded and control mice were subcutaneously infected with 1 LD50 of P. aeruginosa. Survival, bacterial organ load, and antibody and corticosterone levels were compared among the groups. Hindlimb unloading had detrimental effects for infected mice. Animals in the hindlimb-unloaded group, compared with controls, 1). showed significantly increased mortality and reduced time to death, 2). had increased levels of corticosterone, and 3). were much less able to clear bacteria from the organs. These results suggest that hindlimb unloading may induce the production of corticosterone, which may play a critical role in the modulation of the immune system leading to increased susceptibility to P. aeruginosa infection.

  11. Loading and Unloading Finishing Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture.

    PubMed

    Garcia, Arlene; McGlone, John J

    2014-01-01

    The use of non-slip surfaces during loading and unloading of finishing pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps with a slope below 20 degrees to load and unload pigs. However, the total time it takes to load and unload animals and slips, falls, and vocalizations are a welfare concern. Three ramp angles (0, 10 or 20 degrees), five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay), two moistures (dry or wet bedding, >50% moisture) over two seasons (>23.9 °C summer, <23.9 °C winter) were assessed for slips/falls/vocalizations (n = 2400 pig observations) and analyzed with a scoring system. The use of bedding during summer or winter played a role in the total time it took to load and unload the ramp (p < 0.05). Bedding, bedding moisture, season, and slope significantly interacted to impact the total time to load and unload finishing pigs (p < 0.05). Heart rate and the total time it took to load and unload the ramp increased as the slope of the ramp increased (p < 0.05). Heart rates were higher during the summer than winter, and summer heart rates increased as the slope increased (p < 0.05). The current study suggests that several factors should be considered in combination to identify the appropriate bedding for the specific occasion. PMID:26479134

  12. An ergonomics evaluation of cashier work activities at checker-unload workstations.

    PubMed

    Grant, K A; Habes, D J; Baron, S L

    1994-10-01

    The ergonomic suitability of the 'over-the-counter' (OTC) or 'checker unload' workstation for grocery-scanning operations has been questioned by a number of ergonomists, safety and health professionals, and retail food industry executives in the USA. There is concern that requiring cashiers to remove grocery items directly from the customer's cart for scanning exacerbates the risk of musculoskeletal disorders associated with this job. For this reason, a study was conducted to determine whether supermarket cashiers are exposed to increased biomechanical stress due to the use of checker-unload workstations for standing work. The work activities of 12 grocery cashiers from three supermarkets were recorded on videotape. Postures and movements associated with the scanning task were visually evaluated and compared with those of 10 grocery cashiers using a front-facing, customer-unload workstation examined in a previous study. The results indicate that use of the checker-unload workstation places additional stresses on the cashier beyond those imposed by customer-unload checkstands. Specifically, the task of removing groceries directly from the cart for scanning increases the frequency of long reaches, awkward shoulder postures, and lifts. These stresses can be mitigated by eliminating checker-unload operations and providing checkstands with conveyor belts for delivering groceries to the cashier. Implementing additional workstation modifications and encouraging cashiers to adopt alternative work practices also may reduce the frequencies of awkward postures and stressful motions associated with this checkstand design. PMID:15676983

  13. Paradoxical Sost gene expression response to mechanical unloading in metaphyseal bone.

    PubMed

    Macias, Brandon R; Aspenberg, Per; Agholme, Fredrik

    2013-04-01

    The Sost gene encodes Sclerostin, an inhibitor of Wnt-signaling, generally considered a main response gene to mechanical loading in bone. Several papers describe that unloading leads to upregulation of Sost, which in turn may lead to loss of bone. These studies were based on whole bone homogenates or cortical bone. By serendipity, we noted an opposite response to unloading in the proximal rat tibia. Therefore, we hypothesized that Sost-expression in response to changes in mechanical load is bone site specific. One hind limb of male, 3 month old rats was unloaded by paralyzing the extensors with Botulinium toxin A (Botox) injections. A series of experiments compared the expression of Sost mRNA in the unloaded and contralateral, loaded limbs, after 3 or 10 days, in metaphyseal cancellous bone, metaphyseal cortical bone, and diaphyseal cortical bone. We also conducted μCT to confirm changes in bone volume density related to unloading. Sost mRNA expression in the cancellous metaphyseal bone was downregulated almost 2-fold, both 3 days and 10 days after unloading (P<0.05). A similar tendency was seen in the metaphyseal cortical bone, in which Sost was 1.5-fold downregulated (P<0.05) after 10days, but not significantly changed after 3days. In contrast, diaphyseal cortical Sost expression was instead upregulated 1.4-fold (P<0.05) following 3-day unloading, while there was no significant change after 10days. Cancellous bone volume density was 58% lower (P<0.001, compared to cage controls) in the unloaded limb but not significantly affected in the loaded limb. The results suggest that Sost mRNA expression in metaphyseal bone responds to mechanical unloading in an opposite direction to that observed in diaphyseal cortical bone. This proposes a more complex expression pattern for Sost in response to unloading. Therapeutics that target Sclerostin during altered loading conditions may result in local bone mass changes that are difficult to predict. PMID:23337040

  14. Phloem unloading in aerial roots of Monstera deliciosa.

    PubMed

    Eschrich, W

    1983-05-01

    Plants of Monstera deliciosa Liebm. pruned to exemplars with one leaf and one aerial root were labeled with 7.4 MBq (14)CO2 over the leaf blade. Microautoradiographs of soluble and insoluble radioactivity were prepared from three different regions of the aerial root. In addition, histochemical localization of ATPase was carried out on similar aerial roots. Vigorously growing aerial roots grew as fast as 26 mm d(-1), and zones of differentiation extended more than 10 cm from the root tip. In the region 2-3 cm from the root tip, in which only protoelements of the vascular tissue were differentiated, (14)C-label was restricted to the protophloem. The activity of ATPase was recognized in many different cellular organelles of the meristematic phloem parenchyma. In the region 5-6 cm from the root tip, in which the first metaelements differentiated, all parenchyma cells of the central cylinder and many cortical cells showed (14)C-label, in addition to the densely labeled protophloem. Differentiating vessels were heavily labeled at sites where secondary walls were formed. In this region of the root, ATPase activity was concentrated on the plasmalemma and cortical cytoplasma of the sieve tubes, and on the tonoplast of the phloem parenchyma cells. In contrast, the strands of internal metaphloem with giant sieve tubes, which are scattered among the metaxylem, were neither labeled nor did they show ATPase activity. In the zone 19-20 cm from the root tip, regions of cell differentiation in the sclerenchymatic mantle of the inner cortex, the late-formed metaxylem vessels and some strands of the internal metaphloem could be identified by dense (14)C-label. Low ATPase activity was found in the plasmalemma of practically all living cells. In this nearly mature region, a strong peroxidase activity was observed in the radial walls of the endodermis. The results indicate that phloem unloading was strongest at sites of root differentiation, where ATPase activity was concentrated in the

  15. Loading and Unloading Finishing Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

    PubMed Central

    Garcia, Arlene; McGlone, John J.

    2014-01-01

    Simple Summary Current guidelines suggest the use of ramps below 20 degrees to load and unload pigs; however, they do not suggest the use of any specific bedding. Bedding types (nothing, feed, sand, wood shavings, and hay) were tested with finishing pigs (70–120 kg) to determine which was most effective in reducing slips, falls, and vocalizations at three ramp angles, two moisture levels, over two seasons. Slips, falls, and vocalizations were summed to establish a scoring system for the types of beddings. Heart rate and the total time it took to load and unload pigs, increased as the slope increased. Bedding, bedding moisture, season, and ramp slope interacted to impact the total time it took for finishing pigs to load and unload the ramp. Selection of the best bedding depends on ramp slope, season, and wetness of bedding. Abstract The use of non-slip surfaces during loading and unloading of finishing pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps with a slope below 20 degrees to load and unload pigs. However, the total time it takes to load and unload animals and slips, falls, and vocalizations are a welfare concern. Three ramp angles (0, 10 or 20 degrees), five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay), two moistures (dry or wet bedding, >50% moisture) over two seasons (>23.9 °C summer, <23.9 °C winter) were assessed for slips/falls/vocalizations (n = 2400 pig observations) and analyzed with a scoring system. The use of bedding during summer or winter played a role in the total time it took to load and unload the ramp (p < 0.05). Bedding, bedding moisture, season, and slope significantly interacted to impact the total time to load and unload finishing pigs (p < 0.05). Heart rate and the total time it took to load and unload the ramp increased as the slope of the ramp increased (p < 0.05). Heart rates were higher during the

  16. Glucose uptake in rat soleus - Effect of acute unloading and subsequent reloading

    NASA Technical Reports Server (NTRS)

    Henriksen, Eric J.; Tischler, Marc E.

    1988-01-01

    The effect of acutely reduced weight bearing (unloading) on the in vitro uptake of 2-1,2-H-3-deoxy-D-glucose was studied in the soleus muscle by tail casting and suspending rats. After just 4 h, the uptake of 2-deoxy-D-glucose fell (-19 percent) and declined further after an additional 20 h of unloading. This diminution at 24 h was associated with slower oxidation of C-14-glucose and incorporation of C-14-glucose into glycogen. At 3 days of unloading, basal uptake of 2-deoxy-D-glucose did not differ from control. Reloading of the soleus after 1 or 3 days of unloading increased uptake of 2-deoxy-D-glucose above control and returned it to normal within 6 h and 4 days, respectively. These effects of unloading and recovery were caused by local changes in the soleus, because the extensor digitorum longus from the same hindlimbs did not display any alterations in uptake of 2-deoxy-D-glucose or metabolism of glucose.

  17. Skeletal unloading induces resistance to insulin-like growth factor I

    NASA Technical Reports Server (NTRS)

    Bikle, D. D.; Harris, J.; Halloran, B. P.; Morey-Holton, E. R.

    1994-01-01

    In previous studies with a hindlimb elevation model, we demonstrated that skeletal unloading transiently inhibits bone formation. This effect is limited to the unloaded bones (the normally loaded humerus does not cease growing), suggesting that local factors are of prime importance. IGF-I is one such factor; it is produced in bone and stimulates bone formation. To determine the impact of skeletal unloading on IGF-I production and function, we assessed the mRNA levels of IGF-I and its receptor (IGF-IR) in the proximal tibia and distal femur of growing rats during 2 weeks of hindlimb elevation. The mRNA levels for IGF-I and IGF-IR rose during hindlimb elevation, returning toward control values during recovery. This was accompanied by a 77% increase in IGF-I levels in the bone, peaking at day 10 of unloading. Changes in IGF binding protein levels were not observed. Infusion of IGF-I (200 micrograms/day) during 1 week of hindlimb elevation doubled the increase in bone mass of the control animals but failed to reverse the cessation of bone growth in the hindlimb-elevated animals. We conclude that skeletal unloading induces resistance to IGF-I, which may result secondarily in increased local production of IGF-I.

  18. Loading-unloading response of circular GLARE fiber-metal laminates under lateral indentation

    NASA Astrophysics Data System (ADS)

    Tsamasphyros, George J.; Bikakis, George S.

    2015-01-01

    GLARE is a Fiber-Metal laminated material used in aerospace structures which are frequently subjected to various impact damages. Hence, the response of GLARE plates subjected to lateral indentation is very important. In this paper, analytical expressions are derived and a non-linear finite element modeling procedure is proposed in order to predict the static load-indentation curves of circular GLARE plates during loading and unloading by a hemispherical indentor. We have recently published analytical formulas and a finite element procedure for the static indentation of circular GLARE plates which are now used during the loading stage. Here, considering that aluminum layers are in a state of membrane yield and employing energy balance during unloading, the unloading path is determined. Using this unloading path, an algebraic equation is derived for calculating the permanent dent depth of the GLARE plate after the indentor's withdrawal. Furthermore, our finite element procedure is modified in order to simulate the unloading stage as well. The derived formulas and the proposed finite element modeling procedure are applied successfully to GLARE 2-2/1-0.3 and to GLARE 3-3/2-0.4 circular plates. The analytical results are compared with corresponding FEM results and a good agreement is found. The analytically calculated permanent dent depth is within 6 % for the GLARE 2 plate, and within 7 % for the GLARE 3 plate, of the corresponding numerically calculated result. No other solution of this problem is known to the authors.

  19. Effects of Microstructure on the Variation of the Unloading Behavior of DP780 Steels

    NASA Astrophysics Data System (ADS)

    Pavlina, Erik J.; Lin, Chengjiang; Mendiguren, Joseba; Rolfe, Bernard F.; Weiss, Matthias

    2015-10-01

    The nonlinear unloading behavior of three different commercial dual-phase steels (DP780 grade equivalent) was examined. These steels exhibited small variations in chemical composition (0.07 to 0.10 mass percent carbon) and martensite volume fraction (0.23 to 0.28), and they demonstrated similar hardening behavior. Uniaxial loading-unloading-loading tests were conducted at room temperature and quasi-static strain rates between engineering strains of 0.5 and 8%. Steel microstructures were examined using electron backscatter diffraction and nanoindentation techniques. The microplastic component of the unloading strain exhibited no dependence on the martensite volume fraction or the ferrite grain size within the small range encountered in this investigations. Instead, the magnitude of the microplastic component of the unloading strain increased as the strength ratio between the martensite and ferrite phases increased. Correspondingly, the apparent unloading modulus, or chord modulus, exhibited a greater reduction for equivalent increments of strain hardening as the strength ratio increased. These results suggest that springback can be reduced in structures containing two ductile phases if the strength ratio between the harder and softer phases is reduced.

  20. Time course of the response of carbohydrate metabolism to unloading of the soleus

    NASA Technical Reports Server (NTRS)

    Henriksen, Erik J.; Tischler, Marc E.

    1988-01-01

    The time course of the response of carbohydrate metabolism to unloading was studied in the soleus muscle of rats subjected to tail-cast suspension. In the fresh soleus, 12 hours of unloading led to higher concentrations of glycogen and lower activity ratios of both glycogen synthase and glycogen phosphorylase. These changes were still evident on day three. Thereafter, the increased glycogen concentration apparently diminished the activity ratio of glycogen synthase, leading to a subsequent fall in the total glycogen content after day one. After 24 hours of unloading, when no significant atrophy was detectable, there was no differential response to insulin for in vitro glucose metabolism. On day three, the soleus atrophied significantly and displayed a greater sensitivity to insulin for most of these parameters compared to the weight-bearing control muscle. However, insulin sensitivity for glycogen synthesis was unchanged. These results showed that the increased sensitivity to insulin of the unloaded soleus is associated with the degree of muscle atrophy, likely due to an increased insulin binding capacity relative to muscle mass. This study also showed that insulin regulation of glucose uptake and of glycogen synthesis is affected differentially in the unloaded soleus muscle.

  1. Effect of gamma-ray irradiation on the unloaded animal model

    NASA Astrophysics Data System (ADS)

    Choi, Jong-Il; Yoon, Min-Chul; Sung, Nak-Yoon; Kim, Jae-Hun; Jong Lee, Yun; Lee, Ki-Soo; Choi, In-Ho; Nam, Gung Uk; Lee, Ju-Woon

    During the space flight, human beings encountered the extreme conditions such as the cosmic ray irradiation and microgravity. There have been developed the animal models to simulate the microgravity condition in laboratory, but no study was carried out to investigate the combined effect of microgravity and exposure to irradiation. In this study, it was examined the effect of gamma irradiation on the suspension model. Rats were divided into four groups, Group I was loaded and not exposed to gamma irradiation, Group 2 was unloaded and not exposed, Group 3 was loaded and exposed to gamma irradiation at the dose of 50 mSV, and Group 4 was unloaded and exposed to gamma irradiation at the same dose. It was measured body, muscles and tissues weights and the biological analysis and the hematological response in blood samples were conducted. Anti-gravity tissue weight was only changed between loading and un-loading condition. However, there was no difference between irradiation exposed and not exposed unloaded groups. To know the difference of protein expression in anti-gravity tissues, 2 dimensional electrophoresis was performed. It has been found that the expression levels of several proteins were different by unloading condition and by irradiation exposed condition, respectively. These results provided the information on the combined effect of irradiation and microgravity to simulate space flight, and could be useful to search the candidate material for the countermeasure against space environment.

  2. Modeling Loading/Unloading Hysteresis Behavior of Unidirectional C/SiC Ceramic Matrix Composites

    NASA Astrophysics Data System (ADS)

    Longbiao, Li; Yingdong, Song; Youchao, Sun

    2013-08-01

    The loading/unloading tensile behavior of unidirectional C/SiC ceramic matrix composites at room temperature has been investigated. The loading/unloading stress-strain curve exhibits obvious hysteresis behavior. An approach to model the hysteresis loops of ceramic matrix composites including the effect of fiber failure during tensile loading has been developed. By adopting a shear-lag model which includes the matrix shear deformation in the bonded region and friction in the debonded region, the matrix cracking space and interface debonded length are obtained by matrix statistical cracking model and fracture mechanics interface debonded criterion. The two-parameter Weibull model is used to describe the fiber strength distribution. The stress carried by the intact and fracture fibers on the matrix crack plane during unloading and subsequent reloading is determined by the Global Load Sharing criterion. Based on the damage mechanisms of fiber sliding relative to matrix during unloading and subsequent reloading, the unloading interface reverse slip length and reloading interface new slip length are obtained by the fracture mechanics approach. The hysteresis loops of unidirectional C/SiC ceramic matrix composites corresponding to different stress have been predicted.

  3. Genetic and tissue level muscle-bone interactions during unloading and reambulation.

    PubMed

    Judex, S; Zhang, W; Donahue, L R; Ozcivici, E

    2016-01-01

    Little is known about interactions between muscle and bone during the removal and application of mechanical signals. Here, we applied 3wk of hindlimb unloading followed by 3wk of reambulation to a genetically heterogeneous population of 352 adult mice and tested the hypothesis that changes in muscle are associated with changes in bone at the level of the tissue and the genome. During unloading and relative to normally ambulating control mice, most mice lost muscle and cortical bone with large variability across the population. During reambulation, individual mice regained bone and muscle at different rates. Across mice, changes in muscle and trabecular/cortical bone were not correlated to each other during unloading or reambulation. For unloading, we found one significant quantitative trait locus (QTL) for muscle area and five QTLs for cortical bone without overlap between mechano-sensitive muscle and cortical bone QTLs (but some overlap between muscle and trabecular QTLs). The low correlations between morphological changes in muscle and bone, together with the largely distinct genetic regulation of the response indicate that the premise of a muscle-bone unit that co-adjusts its size during (un)loading may need to be reassessed. PMID:27609032

  4. 9 CFR 325.17 - Loading or unloading products in sealed railroad cars, trucks, etc., en route prohibited; exception.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND...; exception. Unloading any product from an officially sealed railroad car, truck, or other means of...

  5. 9 CFR 325.17 - Loading or unloading products in sealed railroad cars, trucks, etc., en route prohibited; exception.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND...; exception. Unloading any product from an officially sealed railroad car, truck, or other means of...

  6. 9 CFR 325.17 - Loading or unloading products in sealed railroad cars, trucks, etc., en route prohibited; exception.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND...; exception. Unloading any product from an officially sealed railroad car, truck, or other means of...

  7. 9 CFR 325.17 - Loading or unloading products in sealed railroad cars, trucks, etc., en route prohibited; exception.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND...; exception. Unloading any product from an officially sealed railroad car, truck, or other means of...

  8. 9 CFR 325.17 - Loading or unloading products in sealed railroad cars, trucks, etc., en route prohibited; exception.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND...; exception. Unloading any product from an officially sealed railroad car, truck, or other means of...

  9. Deglaciation and glacial erosion: A joint control on magma productivity by continental unloading

    NASA Astrophysics Data System (ADS)

    Sternai, Pietro; Caricchi, Luca; Castelltort, Sébastien; Champagnac, Jean-Daniel

    2016-02-01

    Glacial-interglacial cycles affect the processes through which water and rocks are redistributed across the Earth's surface, thereby linking the solid Earth and climate dynamics. Regional and global scale studies suggest that continental lithospheric unloading due to ice melting during the transition to interglacials leads to increased continental magmatic, volcanic, and degassing activity. Such a climatic forcing on the melting of the Earth's interior, however, has always been evaluated regardless of continental unloading by glacial erosion, albeit the density of rock exceeds that of ice by approximately 3 times. Here we present and discuss numerical results involving synthetic but realistic topographies, ice caps, and glacial erosion rates suggesting that erosion may be as important as deglaciation in affecting continental unloading. Our study represents an additional step toward a more general understanding of the links between a changing climate, glacial processes, and the melting of the solid Earth.

  10. Low oxygen [correction of oxygene] tension may defence the bone tissue from unloading simulated osteopenia.

    PubMed

    Berezovskii, V A; Litovka, I G; Kostyuchenko, A S

    2004-07-01

    The main task of the present study is to investigate the influences of normobaric gas mixture with lowered PO2 (90-110 mm Hg) on the bones metabolism in rats after hind limb unloaded (HLU). We observed increased the glycosaminoglicans (GAG) concentration in blood serum rats with hind limb unloaded in atmospheric air (AA). An increased activity of acid phosphatase (AcP) and tartratresistant acid phosphatase (TRAcP) in blood serum of rats after HLU was observed. The activities of the alkaline phosphatase (AIP) in blood serum did not change. An increased osteocalcin (OST) and C-terminal Propeptide of type I Collagen (CICP) concentration in blood serum, but parathyroid hormone (PTH) decrease comparatively with the control. The above mentioned biochemistry markers in animals after 28 days unloading in normobaric gas mixture (NGM) were more stable and in spite of the same procedure in AA, all dates were near to the controls. PMID:16237821

  11. Muscle protein and glycogen responses to recovery from hypogravity and unloading by tail-cast suspension

    NASA Technical Reports Server (NTRS)

    Henriksen, E. J.; Tischler, M. E.; Jacob, S.; Cook, P. H.

    1985-01-01

    Previous studies in this laboratory using the tail-bast hindlimb suspension model have shown that there are specific changes in protein and carbohydrate metabolism in the soleus muscle due to unloading. For example, 6 days of unloading caused a 27% decrease in mass and a 60% increase in glycogen content in the soleus muscle, while the extensor digitorum longus muscle was unaffected. Also, fresh tissue tyrosine and its in vitro release from the muscle are increased in the unloaded soleus, indicating that this condition causes a more negative protein balance. With these results in mind, studies to investigate the effect of hypogravity on protein and carbohydrate metabolism in a number of rat hindlimb muscles were carried out.

  12. Muscle protein and glycogen responses to recovery from hypogravity and unloading by tail-cast suspension

    NASA Technical Reports Server (NTRS)

    Henriksen, E. J.; Tischler, M. E.; Jacob, S.; Cook, P. H.

    1985-01-01

    Previous studies in this laboratory using the tail-bast hindlimb suspension model have shown that there are specific changes in protein and carbohydrate metabolism in the soleus muscle due to unloading. For example, 6 days of unloading caused a 27 percent decrease in mass and a 60 percent increse in glycogen content in the soleus muscle, while the extensor digitorum longus muscle was unaffected. Also, fresh tissue tyrosine and its in vitro release from the muscle are increased in the unloaded soleus, indicating that this condition causes a more negative protein balance. With these results in mind, studies to investigate the effect of hypogravity on protein and carbohydrate metabolism in a number of rat hindlimb muscles were carried out.

  13. Loading-unloading of an elastic-plastic adhesive spherical microcontact.

    PubMed

    Kadin, Y; Kligerman, Y; Etsion, I

    2008-05-01

    A numerical solution is presented for a single load-unload cycle of an adhesive contact between an elastic-plastic sphere and a rigid flat. The interacting forces between the sphere and the flat are obtained through connecting nonlinear spring elements having force-displacement behavior that obeys the Lennard-Jones potential. Kinematic, rather than isotropic, hardening is assumed for the sphere material to account for possible secondary plastification during the unloading. The well-known Tabor parameter and a plasticity parameter are shown to be the two main dimensionless parameters governing the problem. The effects of these two parameters on the load-approach curves, on the plastically deformed sphere profiles, and on the plastic strain fields inside the sphere are presented, showing different modes of separation during the unloading. PMID:18275967

  14. Trichostatin A, a histone deacetylase inhibitor, modulates unloaded-induced skeletal muscle atrophy.

    PubMed

    Dupré-Aucouturier, Sylvie; Castells, Josiane; Freyssenet, Damien; Desplanches, Dominique

    2015-08-15

    Skeletal muscle atrophy is commonly associated with immobilization, ageing, and catabolic diseases such as diabetes and cancer cachexia. Epigenetic regulation of gene expression resulting from chromatin remodeling through histone acetylation has been implicated in muscle disuse. The present work was designed to test the hypothesis that treatment with trichostatin A (TSA), a histone deacetylase inhibitor, would partly counteract unloading-induced muscle atrophy. Soleus muscle atrophy (-38%) induced by 14 days of rat hindlimb suspension was reduced to only 25% under TSA treatment. TSA partly prevented the loss of type I and IIa fiber size and reversed the transitions of slow-twitch to fast-twitch fibers in soleus muscle. Unloading or TSA treatment did not affect myostatin gene expression and follistatin protein. Soleus protein carbonyl content remained unchanged, whereas the decrease in glutathione vs. glutathione disulfide ratio and the increase in catalase activity (biomarkers of oxidative stress) observed after unloading were abolished by TSA treatment. The autophagy-lysosome pathway (Bnip3 and microtubule-associated protein 1 light chain 3 proteins, Atg5, Gabarapl1, Ulk1, and cathepsin B and L mRNA) was not activated by unloading or TSA treatment. However, TSA suppressed the rise in muscle-specific RING finger protein 1 (MuRF1) caused by unloading without affecting the forkhead box (Foxo3) transcription factor. Prevention of muscle atrophy by TSA might be due to the regulation of the skeletal muscle atrophy-related MuRF1 gene. Our findings suggest that TSA may provide a novel avenue to treat unloaded-induced muscle atrophy. PMID:26112243

  15. Vitamin E provides protection for bone in mature hindlimb unloaded male rats

    NASA Technical Reports Server (NTRS)

    Smith, B. J.; Lucas, E. A.; Turner, R. T.; Evans, G. L.; Lerner, M. R.; Brackett, D. J.; Stoecker, B. J.; Arjmandi, B. H.

    2005-01-01

    The deleterious effects of skeletal unloading on bone mass and strength may, in part, result from increased production of oxygen-derived free radicals and proinflammatory cytokines. This study was designed to evaluate the ability of vitamin E (alpha-tocopherol), a free-radical scavenger with antiinflammatory properties, to protect against bone loss caused by skeletal unloading in mature male Sprague-Dawley rats. A 2 x 3 factorial design was used with either hindlimb unloading (HU) or normal loading (ambulatory; AMB), and low-dose (LD; 15 IU/kg diet), adequate-dose (AD; 75 IU/kg diet), or high-dose (HD; 500 IU/kg diet) vitamin E (DL-alpha-tocopherol acetate). To optimize the effects of vitamin E on bone, dietary treatments were initiated 9 weeks prior to unloading and continued during the 4-week unloading period, at which time animals were euthanized and blood and tissue samples were collected. Serum vitamin E was dose-dependently increased, confirming the vitamin E status of animals. The HD treatment improved oxidation parameters, as indicated by elevated serum ferric-reducing ability and a trend toward reducing tissue lipid peroxidation. Histomorphometric analysis of the distal femur revealed significant reductions in trabecular thickness (TbTh), double-labeled surface (dLS/BS), and rate of bone formation to bone volume (BFR/BV) due by HU. AMB animals on the HD diet and HU animals on the LD diet had reduced bone surface normalized to tissue volume (BS/TV) and trabecular number (TbN); however, the HD vitamin E protected against these changes in the HU animals. Our findings suggest that vitamin E supplementation provides modest bone protective effects during skeletal unloading.

  16. Intracellular Ca2+ transients in mouse soleus muscle after hindlimb unloading and reloading

    NASA Technical Reports Server (NTRS)

    Ingalls, C. P.; Warren, G. L.; Armstrong, R. B.; Hamilton, S. L. (Principal Investigator)

    1999-01-01

    The objective of this study was to determine whether altered intracellular Ca(2+) handling contributes to the specific force loss in the soleus muscle after unloading and/or subsequent reloading of mouse hindlimbs. Three groups of female ICR mice were studied: 1) unloaded mice (n = 11) that were hindlimb suspended for 14 days, 2) reloaded mice (n = 10) that were returned to their cages for 1 day after 14 days of hindlimb suspension, and 3) control mice (n = 10) that had normal cage activity. Maximum isometric tetanic force (P(o)) was determined in the soleus muscle from the left hindlimb, and resting free cytosolic Ca(2+) concentration ([Ca(2+)](i)), tetanic [Ca(2+)](i), and 4-chloro-m-cresol-induced [Ca(2+)](i) were measured in the contralateral soleus muscle by confocal laser scanning microscopy. Unloading and reloading increased resting [Ca(2+)](i) above control by 36% and 24%, respectively. Although unloading reduced P(o) and specific force by 58% and 24%, respectively, compared with control mice, there was no difference in tetanic [Ca(2+)](i). P(o), specific force, and tetanic [Ca(2+)](i) were reduced by 58%, 23%, and 23%, respectively, in the reloaded animals compared with control mice; however, tetanic [Ca(2+)](i) was not different between unloaded and reloaded mice. These data indicate that although hindlimb suspension results in disturbed intracellular Ca(2+) homeostasis, changes in tetanic [Ca(2+)](i) do not contribute to force deficits. Compared with unloading, 24 h of physiological reloading in the mouse do not result in further changes in maximal strength or tetanic [Ca(2+)](i).

  17. Disruption of NF-κB1 prevents bone loss caused by mechanical unloading.

    PubMed

    Nakamura, Hitomi; Aoki, Kazuhiro; Masuda, Wataru; Alles, Neil; Nagano, Kenichi; Fukushima, Hidefumi; Osawa, Kenji; Yasuda, Hisataka; Nakamura, Ichiro; Mikuni-Takagaki, Yuko; Ohya, Keiichi; Maki, Kenshi; Jimi, Eijiro

    2013-06-01

    Mechanical unloading, such as in a microgravity environment in space or during bed rest (for patients who require prolonged bed rest), leads to a decrease in bone mass because of the suppression of bone formation and the stimulation of bone resorption. To address the challenges presented by a prolonged stay in space and the forthcoming era of a super-aged society, it will be important to prevent the bone loss caused by prolonged mechanical unloading. Nuclear factor κB (NF-κB) transcription factors are activated by mechanical loading and inflammatory cytokines. Our objective was to elucidate the role of NF-κB pathways in bone loss that are caused by mechanical unloading. Eight-week-old wild-type (WT) and NF-κB1-deficient mice were randomly assigned to a control or mechanically unloaded with tail suspension group. After 2 weeks, a radiographic analysis indicated a decrease in bone mass in the tibias and femurs of the unloaded WT mice but not in the NF-κB1-deficient mice. An NF-κB1 deficiency suppressed the unloading-induced reduction in bone formation by maintaining the proportion and/or potential of osteoprogenitors or immature osteoblasts, and by suppression of bone resorption through the inhibition of intracellular signaling through the receptor activator of NF-κB ligand (RANKL) in osteoclast precursors. Thus, NF-κB1 is involved in two aspects of rapid reduction in bone mass that are induced by disuse osteoporosis in space or bed rest. PMID:23322687

  18. Involvement of AMPK in regulating slow-twitch muscle atrophy during hindlimb unloading in mice.

    PubMed

    Egawa, Tatsuro; Goto, Ayumi; Ohno, Yoshitaka; Yokoyama, Shingo; Ikuta, Akihiro; Suzuki, Miho; Sugiura, Takao; Ohira, Yoshinobu; Yoshioka, Toshitada; Hayashi, Tatsuya; Goto, Katsumasa

    2015-10-01

    AMPK is considered to have a role in regulating skeletal muscle mass. However, there are no studies investigating the function of AMPK in modulating skeletal muscle mass during atrophic conditions. In the present study, we investigated the difference in unloading-associated muscle atrophy and molecular functions in response to 2-wk hindlimb suspension between transgenic mice overexpressing the dominant-negative mutant of AMPK (AMPK-DN) and their wild-type (WT) littermates. Male WT (n = 24) and AMPK-DN (n = 24) mice were randomly divided into two groups: an untreated preexperimental control group (n = 12 in each group) and an unloading (n = 12 in each group) group. The relative soleus muscle weight and fiber cross-sectional area to body weight were decreased by ∼30% in WT mice by hindlimb unloading and by ∼20% in AMPK-DN mice. There were no changes in puromycin-labeled protein or Akt/70-kDa ribosomal S6 kinase signaling, the indicators of protein synthesis. The expressions of ubiquitinated proteins and muscle RING finger 1 mRNA and protein, markers of the ubiquitin-proteasome system, were increased by hindlimb unloading in WT mice but not in AMPK-DN mice. The expressions of molecules related to the protein degradation system, phosphorylated forkhead box class O3a, inhibitor of κBα, microRNA (miR)-1, and miR-23a, were decreased only in WT mice in response to hindlimb unloading, and 72-kDa heat shock protein expression was higher in AMPK-DN mice than in WT mice. These results imply that AMPK partially regulates unloading-induced atrophy of slow-twitch muscle possibly through modulation of the protein degradation system, especially the ubiquitin-proteasome system. PMID:26244519

  19. Regulation of contractile protein gene expression in unloaded mouse skeletal muscle

    NASA Technical Reports Server (NTRS)

    Criswell, D. S.; Carson, J. A.; Booth, F. W.

    1996-01-01

    Hindlimb unloading was performed on mice in an effort to study the regulation of contractile protein genes. In particular, the regulation of myosin heavy chain IIb was examined. During unloading, muscle fibers undergo a type conversion. Preliminary data from this study does not support the hypothesis that the fiber type conversion is due to an increase in promoter activity of fast isoform genes, such as myosin heavy chain IIb. The consequences of this finding are examined, with particular focus on other factors controlling gene regulation.

  20. Insulin effect on amino acid uptake by unloaded rat hindlimb muscles

    NASA Technical Reports Server (NTRS)

    Jaspers, S. R.; Tischler, M. E.

    1988-01-01

    The effect of insulin on the uptake of alpha-amino-isobutyric acid (AIB) by unloaded rat hindlimb muscles was investigated using soleus and extensor digitorum longus (EDL) muscles from intact and adrenalectomized (ADX) rats that were tail-casted for six days. It was found that, at insulin levels above 0.00001 units/ml, the in vitro rate of AIB uptake by muscles from intact animals was stimulated more in the weight bearing muscles than in unloaded ones. In ADX animals, this differential response to insulin was abolished.

  1. 9 CFR 72.17 - Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Unloading noninfected cattle for rest... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS TEXAS (SPLENETIC) FEVER IN CATTLE § 72.17 Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for such...

  2. 9 CFR 72.17 - Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Unloading noninfected cattle for rest... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS TEXAS (SPLENETIC) FEVER IN CATTLE § 72.17 Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for such...

  3. 9 CFR 72.17 - Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Unloading noninfected cattle for rest... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS TEXAS (SPLENETIC) FEVER IN CATTLE § 72.17 Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for such...

  4. 78 FR 41853 - Safety Advisory Guidance: Heating Rail Tank Cars To Prepare Hazardous Material for Unloading or...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-12

    ...This guidance provides safety precautions and recommended guidance for persons responsible for unloading or transloading \\1\\ hazardous materials from rail tank cars, specifically those persons heating a rail tank car to prepare its hazardous material contents for unloading or transloading. Further, this guidance reminds such persons of current regulatory requirements addressing this type of......

  5. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Gauging devices, top loading and unloading devices... and 115AW) § 179.200-16 Gauging devices, top loading and unloading devices, venting and air inlet...). In no case shall the wall thickness be less than that specified in § 179.201-1. (f) When top...

  6. 49 CFR 179.220-17 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.220-17 Section 179.220-17 Transportation Other Regulations Relating to... and 115AW) § 179.220-17 Gauging devices, top loading and unloading devices, venting and air...

  7. 49 CFR 179.220-17 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.220-17 Section 179.220-17 Transportation Other Regulations Relating to... and 115AW) § 179.220-17 Gauging devices, top loading and unloading devices, venting and air...

  8. 49 CFR 179.220-17 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.220-17 Section 179.220-17 Transportation Other Regulations Relating to... DOT-111AW and 115AW) § 179.220-17 Gauging devices, top loading and unloading devices, venting and...

  9. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Gauging devices, top loading and unloading devices... and 115AW) § 179.200-16 Gauging devices, top loading and unloading devices, venting and air inlet...). In no case shall the wall thickness be less than that specified in § 179.201-1. (f) When top...

  10. 49 CFR 179.220-17 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.220-17 Section 179.220-17 Transportation Other Regulations Relating to... and 115AW) § 179.220-17 Gauging devices, top loading and unloading devices, venting and air...

  11. 49 CFR 179.220-17 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Gauging devices, top loading and unloading devices, venting and air inlet devices. 179.220-17 Section 179.220-17 Transportation Other Regulations Relating to... and 115AW) § 179.220-17 Gauging devices, top loading and unloading devices, venting and air...

  12. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Gauging devices, top loading and unloading devices... and 115AW) § 179.200-16 Gauging devices, top loading and unloading devices, venting and air inlet...). In no case shall the wall thickness be less than that specified in § 179.201-1. (f) When top...

  13. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Gauging devices, top loading and unloading devices... and 115AW) § 179.200-16 Gauging devices, top loading and unloading devices, venting and air inlet...). In no case shall the wall thickness be less than that specified in § 179.201-1. (f) When top...

  14. 49 CFR 179.200-16 - Gauging devices, top loading and unloading devices, venting and air inlet devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Gauging devices, top loading and unloading devices... DOT-111AW and 115AW) § 179.200-16 Gauging devices, top loading and unloading devices, venting and air...). In no case shall the wall thickness be less than that specified in § 179.201-1. (f) When top...

  15. Replication-Coupled PCNA Unloading by the Elg1 Complex Occurs Genome-wide and Requires Okazaki Fragment Ligation.

    PubMed

    Kubota, Takashi; Katou, Yuki; Nakato, Ryuichiro; Shirahige, Katsuhiko; Donaldson, Anne D

    2015-08-01

    The sliding clamp PCNA is a crucial component of the DNA replication machinery. Timely PCNA loading and unloading are central for genome integrity and must be strictly coordinated with other DNA processing steps during replication. Here, we show that the S. cerevisiae Elg1 replication factor C-like complex (Elg1-RLC) unloads PCNA genome-wide following Okazaki fragment ligation. In the absence of Elg1, PCNA is retained on chromosomes in the wake of replication forks, rather than at specific sites. Degradation of the Okazaki fragment ligase Cdc9 leads to PCNA accumulation on chromatin, similar to the accumulation caused by lack of Elg1. We demonstrate that Okazaki fragment ligation is the critical prerequisite for PCNA unloading, since Chlorella virus DNA ligase can substitute for Cdc9 in yeast and simultaneously promotes PCNA unloading. Our results suggest that Elg1-RLC acts as a general PCNA unloader and is dependent upon DNA ligation during chromosome replication. PMID:26212319

  16. Skeletal unloading inhibits the in vitro proliferation and differentiation of rat osteoprogenitor cells

    NASA Technical Reports Server (NTRS)

    Kostenuik, P. J.; Halloran, B. P.; Morey-Holton, E. R.; Bikle, D. D.

    1997-01-01

    Loss of weight bearing in the growing rat decreases bone formation, osteoblast numbers, and bone maturation in unloaded bones. These responses suggest an impairment of osteoblast proliferation and differentiation. To test this assumption, we assessed the effects of skeletal unloading using an in vitro model of osteoprogenitor cell differentiation. Rats were hindlimb elevated for 0 (control), 2, or 5 days, after which their tibial bone marrow stromal cells (BMSCs) were harvested and cultured. Five days of hindlimb elevation led to significant decreases in proliferation, alkaline phosphatase (AP) enzyme activity, and mineralization of BMSC cultures. Differentiation of BMSCs was analyzed by quantitative competitive polymerase chain reaction of cDNA after 10, 15, 20, and 28 days of culture. cDNA pools were analyzed for the expression of c-fos (an index of proliferation), AP (an index of early osteoblast differentiation), and osteocalcin (a marker of late differentiation). BMSCs from 5-day unloaded rats expressed 50% less c-fos, 61% more AP, and 35% less osteocalcin mRNA compared with controls. These data demonstrate that cultured osteoprogenitor cells retain a memory of their in vivo loading history and indicate that skeletal unloading inhibits proliferation and differentiation of osteoprogenitor cells in vitro.

  17. 48 CFR 52.247-19 - Stopping in Transit for Partial Unloading.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Stopping in Transit for... Clauses 52.247-19 Stopping in Transit for Partial Unloading. As prescribed in 47.207-6(c)(5)(ii), insert... origin to two or more consignees along the route between origin and last destination: Stopping in...

  18. 48 CFR 52.247-19 - Stopping in Transit for Partial Unloading.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Stopping in Transit for... Clauses 52.247-19 Stopping in Transit for Partial Unloading. As prescribed in 47.207-6(c)(5)(ii), insert... origin to two or more consignees along the route between origin and last destination: Stopping in...

  19. 48 CFR 52.247-19 - Stopping in Transit for Partial Unloading.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Stopping in Transit for... Clauses 52.247-19 Stopping in Transit for Partial Unloading. As prescribed in 47.207-6(c)(5)(ii), insert... origin to two or more consignees along the route between origin and last destination: Stopping in...

  20. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Venting, loading and unloading valves. 179.300-13 Section 179.300-13 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications...

  1. 76 FR 13313 - Hazardous Materials: Cargo Tank Motor Vehicle Loading and Unloading Operations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-11

    ... DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477..., PHMSA published a notice (73 FR 916) to solicit comments and information on a set of recommended... the greatest single primary cause of incidents during loading and unloading operations, accounting...

  2. Regional alterations of type I collagen in rat tibia induced by skeletal unloading

    NASA Technical Reports Server (NTRS)

    Shiiba, Masashi; Arnaud, Sara B.; Tanzawa, Hideki; Kitamura, Eiji; Yamauchi, Mitsuo

    2002-01-01

    Skeletal unloading induces loss of mineral density in weight-bearing bones that leads to inferior bone mechanical strength. This appears to be caused by a failure of bone formation; however, its mechanisms still are not well understood. The objective of this study was to characterize collagen, the predominant matrix protein in bone, in various regions of tibia of rats that were subjected to skeletal unloading by 4 weeks tail suspension. Sixteen male Sprague-Dawley rats (4 months old) were divided into tail suspension and ambulatory controls (eight rats each). After the tail suspension, tibias from each animal were collected and divided into five regions and collagen was analyzed. The collagen cross-linking and the extent of lysine (Lys) hydroxylation in unloaded bones were significantly altered in proximal epiphysis, diaphysis, and, in particular, proximal metaphysis but not in distal regions. The pool of immature/nonmineralized collagen measured by its extractability with a chaotropic solvent was significantly increased in proximal metaphysis. These results suggest that skeletal unloading induced an accumulation of post-translationally altered nonmineralized collagen and that these changes are bone region specific. These alterations might be caused by impaired osteoblastic function/differentiation resulting in a mineralization defect.

  3. 15 CFR 758.5 - Conformity of documents and unloading of items.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Conformity of documents and unloading of items. 758.5 Section 758.5 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT...

  4. 9 CFR 95.25 - Transportation of restricted import products; placarding cars and marking billing; unloading...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...: Nature of emergency; place where product or material was unloaded; original points of shipment and... product.” These placards shall also bear the words “Clean and disinfect this car or truck.” Each of the... words “Restricted import product, clean and disinfect car or truck,” plainly written or stamped upon...

  5. Dynamic Foot Stimulation Attenuates Soleus Muscle Atrophy Induced by Hindlimb Unloading in Rats

    NASA Technical Reports Server (NTRS)

    Kyparos, Antonios; Feeback, Daniel L.; Layne, Charles S.; Martinez, Daniel A.; Clarke, Mark S. F.

    2004-01-01

    Unloading-induced myofiber atrophy is a phenomenon that occurs in the aging population, bed-ridden patients and astronauts. The objective of this study was to determine whether or not dynamic foot stimulation (DFS) applied to the plantar surface of the rat foot can serve as a countermeasure to the soleus muscle atrophy normally observed in hindlimb unloaded (HU) rats. Thirty mature adult (6-month-old) male Wistar rats were randomly assigned into ambulatory control (AMB), hindlimb unloaded alone (HU), or hindlimb unloaded with the application of DFS (HU+DFS) groups. A dynamic pattern of pressure was applied to the right foot of each HU animal using a specially fabricated boot containing an inflatable air bladder connected to a solenoid air pump controlled by a laptop computer. The anti-atrophic effects of DFS were quantified morphometrically in frozen cross-sections of soleus muscle stained using the metachromatic-ATPase fiber typing technique. Application of DFS during HU significantly counteracted the atrophic response observed in the soleus by preventing approximately 85% of the reduction in Type I myofiber cross-sectional area (CSA) observed during HU. However, DFS did not protect type II fibers of the soleus from HU-induced atrophy or any fiber type in the soleus muscle of the contralateral control leg of the DFS-treated HU animals. These results illustrate that the application of DFS to the rat foot is an effective countermeasure to soleus muscle atrophy induced by HU.

  6. Modulation of Sarcoplasmic Reticulum Calcium Pump (SERCA) Function by Membrane Cholesterol during Unloading

    NASA Astrophysics Data System (ADS)

    Clarke, M. S. F.; Hammond, D. K.; Feeback, D. L.

    2002-01-01

    We have recently demonstrated by in situ immuno-localization that cholesterol is predominantly located in the sarcoplasmic reticulum (SR), rather than in the sarcolemmal/T-tubule (SL-TT) membranes of both human and rat skeletal muscle (Clarke et al., 2000, JAP). In addition, we have demonstrated that mechanical unloading of skeletal muscle in a rat hindlimb suspension model significantly increases membrane cholesterol content and that this increase is also localized to SR rather than SL-TT membranes in such atrophied muscle. Utilizing a novel fluorescent calcium staining technique in perfusion fixed soleus muscle we observed a significant positive correlation between membrane cholesterol content and free intramyofiber calcium levels during unloading. To determine if a correlation between increased SR membrane cholesterol content and increased free intramyofiber calcium levels during unloading is due to a membrane cholesterol-mediated alteration in SR calcium pump function, we also describe the effects of modulating the cholesterol content of purified SR membrane preparations on SR-Ca2+ ATPase activity and ryanodine channel activity. As an increase in free intra-cellular calcium levels have previously demonstrated to induce catabolism in a wide range of biological systems, we suggest that altered SR calcium pump function may be the underlying basis for the initiation of unloading induced muscle atrophy.

  7. Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture.

    PubMed

    Garcia, Arlene; McGlone, John J

    2014-01-01

    The use of non-slip surfaces during loading and unloading of weaned pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps below 20° to load and unload pigs. Three ramp angles (0°, 10° or 20°), five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay), two moistures (dry or wet bedding; >50% moisture) over two seasons (>23.9 °C summer, <23.9 °C winter) were assessed for slips/falls/vocalizations (n = 6,000 pig observations). "Score" was calculated by the sum of slips, falls, and vocalizations. With the exception of using feed as a bedding, all beddings provided some protection against elevated slips, falls, and vocalizations (P < 0.01). Providing bedding reduced (P < 0.05) scores regardless of whether the bedding was dry or wet. Scores increased as the slope increased (P < 0.01). Provision of bedding, other than feed, at slopes greater than zero, decreased slips, falls and vocalizations. The total time it took to load and unload pigs was affected by bedding type, ramp angle, and season (P < 0.05). Minimizing slips, falls, and vocalizations when loading and unloading pigs improved animal welfare. PMID:26479010

  8. The Effect of Skeletal Unloading on Bone Formation: Role of IGF-I

    NASA Technical Reports Server (NTRS)

    Bikle, D. D.; Kostenuik, P.; Holton, E. M.; Halloran, B. P.

    1999-01-01

    The best documented change in bone during space flight is the near cessation of bone formation. Space flight leads to a decrease in osteoblast number and activity, likely the result of altered differentiation of osteoblast precursors. The net result of these space flight induced changes is weaker bone. To understand the mechanism for these changes poses a challenge. Space flight studies must overcome enormous technical problems, and are necessarily limited in size and frequency. Therefore, ground based models have been developed to evaluate the effects of skeletal unloading. The hindlimb elevation (tail suspension) model simulates space flight better than other models because it reproduces the fluid shifts seen in space travel, is reversible, and is well tolerated by the animals with minimal evidence of stress as indicated by continued weight gain and normal levels and circadian rhythms of corticosterone. This is the model we have used for our experiments. Skeletal unloading by the hindlimb elevation method simulates a number of features of space flight in that bone formation, mineralization, and maturation are inhibited, osteoblast number is decreased, serum and skeletal osteocalcin levels fall, the ash content of bone decreases, and bone strength diminishes. We and others have shown that when osteoblasts or osteoprogenitor cells from the bones of the unloaded limbs are cultured in vitro they proliferate and differentiate more slowly, suggesting that skeletal unloading causes a persistent change in cell function which can be assessed in vitro. In contrast to the unweighted bones of the hindlimbs, no significant change in bone mass or bone formation is observed in the humeri, mandible, and cervical vertebrae during hindlimb elevation. The lack of effect of hindlimb elevation on bones like the humeri, mandible, and cervical vertebrae which are not unloaded by this procedure suggests that local factors rather than systemic effects dominate the response of bone to

  9. Paradoxical Response to Mechanical Unloading in Bone Loss, Microarchitecture, and Bone Turnover Markers

    PubMed Central

    Sun, Xiaodi; Yang, Kaiyun; Wang, Chune; Cao, Sensen; Merritt, Mackenzie; Hu, Yingwei; Xu, Xin

    2015-01-01

    Background: Sclerostin, encoded by the SOST gene, has been implicated in the response to mechanical loading in bone. Some studies demonstrated that unloading leads to up-regulated SOST expression, which may induce bone loss. Purpose: Most reported studies regarding the changes caused by mechanical unloading were only based on a single site. Considering that the longitudinal bone growth leads to cells of different age with different sensitivity to unloading, we hypothesized that bone turnover in response to unloading is site specific. Methods: We established a disuse rat model by sciatic neurectomy in tibia. In various regions at two time-points, we evaluated the bone mass and microarchitecture in surgically-operated rats and control rats by micro-Computed Tomography (micro-CT) and histology, sclerostin/SOST by immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), and quantitative reverse transcription polymerase chain reaction (qPCR), tartrate resistant acid phosphatase 5b (TRAP 5b) by ELISA and TRAP staining, and other bone markers by ELISA. Results: Micro-CT and histological analysis confirmed bone volume in the disuse rats was significantly decreased compared with those in the time-matched control rats, and microarchitecture also changed 2 and 8 weeks after surgery. Compared with the control groups, SOST mRNA expression in the diaphysis was down-regulated at both week 2 and 8. On the contrary, the percentage of sclerostin-positive osteocytes showed an up-regulated response in the 5 - 6 mm region away from the growth plate, while in the 2.5 - 3.5 mm region, the percentage was no significant difference. Nevertheless, in 0.5 - 1.5 mm region, the percentage of sclerostin-positive osteocytes decreased after 8 weeks, consistent with serum SOST level. Besides, the results of TRAP also suggested that the expression in response to unloading may be opposite in different sites or system. Conclusion: Our data indicated that unloading-induced changes in bone

  10. Micro-macro correlations and anisotropy in granular assemblies under uniaxial loading and unloading

    NASA Astrophysics Data System (ADS)

    Imole, Olukayode I.; Wojtkowski, Mateusz; Magnanimo, Vanessa; Luding, Stefan

    2014-04-01

    The influence of contact friction on the behavior of dense, polydisperse granular assemblies under uniaxial (oedometric) loading and unloading deformation is studied using discrete element simulations. Even though the uniaxial deformation protocol is one of the "simplest" element tests possible, the evolution of the structural anisotropy necessitates its careful analysis and understanding, since it is the source of interesting and unexpected observations. On the macroscopic, homogenized, continuum scale, the deviatoric stress ratio and the deviatoric fabric, i.e., the microstructure behave in a different fashion during uniaxial loading and unloading. The maximal stress ratio and strain increase with increasing contact friction. In contrast, the deviatoric fabric reaches its maximum at a unique strain level independent of friction, with the maximal value decreasing with friction. For unloading, both stress and fabric respond to unloading strain with a friction-dependent delay but at different strains. On the micro-level, a friction-dependent non-symmetry of the proportion of weak (strong) and sliding (sticking) contacts with respect to the total contacts during loading and unloading is observed. Coupled to this, from the directional probability distribution, the "memory" and history-dependent behavior of granular systems is confirmed. Surprisingly, while a rank-2 tensor is sufficient to describe the evolution of the normal force directions, a sixth order harmonic approximation is necessary to describe the probability distribution of contacts, tangential force, and mobilized friction. We conclude that the simple uniaxial deformation activates microscopic phenomena not only in the active Cartesian directions, but also at intermediate orientations, with the tilt angle being dependent on friction, so that this microstructural features cause the interesting, nontrivial macroscopic behavior.

  11. The Wnt Inhibitor Sclerostin Is Up-regulated by Mechanical Unloading in Osteocytes in Vitro.

    PubMed

    Spatz, Jordan M; Wein, Marc N; Gooi, Jonathan H; Qu, Yili; Garr, Jenna L; Liu, Shawn; Barry, Kevin J; Uda, Yuhei; Lai, Forest; Dedic, Christopher; Balcells-Camps, Mercedes; Kronenberg, Henry M; Babij, Philip; Pajevic, Paola Divieti

    2015-07-01

    Although bone responds to its mechanical environment, the cellular and molecular mechanisms underlying the response of the skeleton to mechanical unloading are not completely understood. Osteocytes are the most abundant but least understood cells in bones and are thought to be responsible for sensing stresses and strains in bone. Sclerostin, a product of the SOST gene, is produced postnatally primarily by osteocytes and is a negative regulator of bone formation. Recent studies show that SOST is mechanically regulated at both the mRNA and protein levels. During prolonged bed rest and immobilization, circulating sclerostin increases both in humans and in animal models, and its increase is associated with a decrease in parathyroid hormone. To investigate whether SOST/sclerostin up-regulation in mechanical unloading is a cell-autonomous response or a hormonal response to decreased parathyroid hormone levels, we subjected osteocytes to an in vitro unloading environment achieved by the NASA rotating wall vessel system. To perform these studies, we generated a novel osteocytic cell line (Ocy454) that produces high levels of SOST/sclerostin at early time points and in the absence of differentiation factors. Importantly, these osteocytes recapitulated the in vivo response to mechanical unloading with increased expression of SOST (3.4 ± 1.9-fold, p < 0.001), sclerostin (4.7 ± 0.1-fold, p < 0.001), and the receptor activator of nuclear factor κΒ ligand (RANKL)/osteoprotegerin (OPG) (2.5 ± 0.7-fold, p < 0.001) ratio. These data demonstrate for the first time a cell-autonomous increase in SOST/sclerostin and RANKL/OPG ratio in the setting of unloading. Thus, targeted osteocyte therapies could hold promise as novel osteoporosis and disuse-induced bone loss treatments by directly modulating the mechanosensing cells in bone. PMID:25953900

  12. The influence of antiorthostatic unloading and long gamma-irradiation on rat bone marrow (MSCs)

    NASA Astrophysics Data System (ADS)

    Roe, Maria; Bobyleva, Polina; Shtemberg, Andrey; Buravkova, Ludmila

    With the prospect of long interplanetary spaceflight becoming a real possibility there are some important questions that need to be answered regarding the combined effects of microgravity and long gamma-irradiation.The aim of this study was to evaluate the effects of synchronous antiorthostatic unloading and fractional gamma-irradiation on the functional characteristics of rat bone marrow multipotent stromal cells (MSCs).This experiment was carried out following all rules laid out by the Commission on Bioethics at the SSC RF - IBMP RAS. In this experiment the Wistar rats were kept in an unloaded position for a duration of 30 days. They were also subjected to 6 doses of gamma-radiation on the “GOBO-60” with a source of (137) Cs. The dose rate set to 1 meter 50 sGr / H (Total dose of 3 Gr).The study revealed a significant reduction in the number of colonies (CFU-F) in all cultures from the experimental groups when compared to the control groups. The most significant reduction was observed in the group, which had been subject to combined unloading, and radiation. This result was confirmed by examination of cell cultures during 10 days of growth.We found that the CD45 expression was increased in the groups exposed to radiation. At the same time a reduction in the expression of CD90 was observed during combination of radiation and unloading we found.The experimental groups also differed from the control group showing smaller lipid inclusions and decreased expression of alkaline phosphates in the MSCs. This experiment concluded that the bone marrow MSCs after a combination of unloading and multiple radiation sessions, showed a decrease in proliferation and differentiation potential which could reduce the adaption and reparative capacity of the organism.

  13. True Triaxial Strength and Failure Modes of Cubic Rock Specimens with Unloading the Minor Principal Stress

    NASA Astrophysics Data System (ADS)

    Li, Xibing; Du, Kun; Li, Diyuan

    2015-11-01

    True triaxial tests have been carried out on granite, sandstone and cement mortar using cubic specimens with the process of unloading the minor principal stress. The strengths and failure modes of the three rock materials are studied in the processes of unloading σ 3 and loading σ 1 by the newly developed true triaxial test system under different σ 2, aiming to study the mechanical responses of the rock in underground excavation at depth. It shows that the rock strength increases with the raising of the intermediate principal stress σ 2 when σ 3 is unloaded to zero. The true triaxial strength criterion by the power-law relationship can be used to fit the testing data. The "best-fitting" material parameters A and n ( A > 1.4 and n < 1.0) are almost located in the same range as expected by Al-Ajmi and Zimmerman (Int J Rock Mech Min Sci 563 42(3):431-439, 2005). It indicates that the end effect caused by the height-to-width ratio of the cubic specimens will not significantly affect the testing results under true triaxial tests. Both the strength and failure modes of cubic rock specimens under true triaxial unloading condition are affected by the intermediate principal stress. When σ 2 increases to a critical value for the strong and hard rocks (R4, R5 and R6), the rock failure mode may change from shear to slabbing. However, for medium strong and weak rocks (R3 and R2), even with a relatively high intermediate principal stress, they tend to fail in shear after a large amount of plastic deformation. The maximum extension strain criterion Stacey (Int J Rock Mech Min Sci Geomech Abstr 651 18(6):469-474, 1981) can be used to explain the change of failure mode from shear to slabbing for strong and hard rocks under true triaxial unloading test condition.

  14. The Wnt Inhibitor Sclerostin Is Up-regulated by Mechanical Unloading in Osteocytes in Vitro*

    PubMed Central

    Spatz, Jordan M.; Wein, Marc N.; Gooi, Jonathan H.; Qu, Yili; Garr, Jenna L.; Liu, Shawn; Barry, Kevin J.; Uda, Yuhei; Lai, Forest; Dedic, Christopher; Balcells-Camps, Mercedes; Kronenberg, Henry M.; Babij, Philip; Pajevic, Paola Divieti

    2015-01-01

    Although bone responds to its mechanical environment, the cellular and molecular mechanisms underlying the response of the skeleton to mechanical unloading are not completely understood. Osteocytes are the most abundant but least understood cells in bones and are thought to be responsible for sensing stresses and strains in bone. Sclerostin, a product of the SOST gene, is produced postnatally primarily by osteocytes and is a negative regulator of bone formation. Recent studies show that SOST is mechanically regulated at both the mRNA and protein levels. During prolonged bed rest and immobilization, circulating sclerostin increases both in humans and in animal models, and its increase is associated with a decrease in parathyroid hormone. To investigate whether SOST/sclerostin up-regulation in mechanical unloading is a cell-autonomous response or a hormonal response to decreased parathyroid hormone levels, we subjected osteocytes to an in vitro unloading environment achieved by the NASA rotating wall vessel system. To perform these studies, we generated a novel osteocytic cell line (Ocy454) that produces high levels of SOST/sclerostin at early time points and in the absence of differentiation factors. Importantly, these osteocytes recapitulated the in vivo response to mechanical unloading with increased expression of SOST (3.4 ± 1.9-fold, p < 0.001), sclerostin (4.7 ± 0.1-fold, p < 0.001), and the receptor activator of nuclear factor κΒ ligand (RANKL)/osteoprotegerin (OPG) (2.5 ± 0.7-fold, p < 0.001) ratio. These data demonstrate for the first time a cell-autonomous increase in SOST/sclerostin and RANKL/OPG ratio in the setting of unloading. Thus, targeted osteocyte therapies could hold promise as novel osteoporosis and disuse-induced bone loss treatments by directly modulating the mechanosensing cells in bone. PMID:25953900

  15. The role of 1,25-dihydroxyvitamin D in the inhibition of bone formation induced by skeletal unloading

    NASA Technical Reports Server (NTRS)

    Halloran, B. P.; Bikle, D. D.; Wronski, T. J.; GLOBUS. R.; Levens, M. J.; Morey-Holton, E.

    1983-01-01

    Skeletal unloading results in osteopenia. To examine the involvement of vitamin D in this process, the rear limbs of growing rats were unloaded and alterations in bone calcium and bone histology were related to changes in serum calcium (Ca), inorganic phosphorus (P sub i), 25-hydroxyvitamin D (25-OH-D), 24,25-dihydroxyvitamin D (24,25(OH)2D and 1,25-dihydroxyvitamin D (1,25(OH)2D. Acute skeletal unloading induced a transitory inhibition of Ca accumulation in unloaded bones. This was accompanied by a transitory rise in serum Ca, a 21% decrease in longitudinal bone growth (P 0.01), a 32% decrease in bone surface lined with osteoblasts (P .05), no change in bone surface lined with osteoclasts and a decrease in circulating (1,25(OH)2D. No significant changes in the serum concentrations of P sub i, 25-OH-D or 24,25(OH)2D were observed. After 2 weeks of unloading, bone Ca stabilized at approximately 70% of control and serum Ca and 1,25(OH)2D returned to control values. Maintenance of a constant serum 1,25(OH)2D concentration by chronic infusion of 1,25(OH)2D (Alza osmotic minipump) throughout the study period did not prevent the bone changes induced by acute unloading. These results suggest that acute skeletal unloading in the growing rat produces a transitory inhibition of bone formation which in turn produces a transitory hypercalcemia.

  16. Combined effects of soy isoflavones and milk basic protein on bone mineral density in hind-limb unloaded mice

    PubMed Central

    Matsumoto, Yu; Tousen, Yuko; Nishide, Yoriko; Tadaishi, Miki; Kato, Ken; Ishimi, Yoshiko

    2016-01-01

    We examined whether the combination of isoflavone and milk basic protein both are reported to be effective for bone metabolism, prevents bone loss induced by skeletal hind-limb unloading in mice. Female ddY strain mice, aged 8 weeks, were divided into six groups (n = 6–8 each): (1) normally housed group, (2) loading group, (3) hind-limb unloading group fed a control diet, (4) hind-limb unloading group fed a 0.2% isoflavone conjugates diet, (5) hind-limb unloading group fed a 1.0% milk basic protein diet, and (6) hind-limb unloading group fed a 0.2% isoflavone conjugates and 1.0% milk basic protein diet. After 3 weeks, femoral bone mineral density was markedly reduced in unloading mice. The combination of isoflavone and milk basic protein showed cooperative effects in preventing bone loss and milk basic protein inhibited the increased expression of osteogenic genes in bone marrow cells in unloading mice. These results suggest that the combination of soy isoflavone and milk basic protein may be useful for bone health in subjects with disabling conditions as well as astronauts. PMID:27013781

  17. Combined effects of soy isoflavones and milk basic protein on bone mineral density in hind-limb unloaded mice.

    PubMed

    Matsumoto, Yu; Tousen, Yuko; Nishide, Yoriko; Tadaishi, Miki; Kato, Ken; Ishimi, Yoshiko

    2016-03-01

    We examined whether the combination of isoflavone and milk basic protein both are reported to be effective for bone metabolism, prevents bone loss induced by skeletal hind-limb unloading in mice. Female ddY strain mice, aged 8 weeks, were divided into six groups (n = 6-8 each): (1) normally housed group, (2) loading group, (3) hind-limb unloading group fed a control diet, (4) hind-limb unloading group fed a 0.2% isoflavone conjugates diet, (5) hind-limb unloading group fed a 1.0% milk basic protein diet, and (6) hind-limb unloading group fed a 0.2% isoflavone conjugates and 1.0% milk basic protein diet. After 3 weeks, femoral bone mineral density was markedly reduced in unloading mice. The combination of isoflavone and milk basic protein showed cooperative effects in preventing bone loss and milk basic protein inhibited the increased expression of osteogenic genes in bone marrow cells in unloading mice. These results suggest that the combination of soy isoflavone and milk basic protein may be useful for bone health in subjects with disabling conditions as well as astronauts. PMID:27013781

  18. Effects of the hindlimb-unloading model of spaceflight conditions on resistance of mice to infection with Klebsiella pneumoniae

    NASA Technical Reports Server (NTRS)

    Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

    2002-01-01

    BACKGROUND: It has been well documented in several studies that many immunologic parameters are altered in experimental animals and human subjects who have flown in space. However, it is not fully known whether these immunologic changes could result in increased susceptibility to infection. Hindlimb (antiorthostatic) unloading of rodents has been used successfully to simulate some of the effects of spaceflight on physiologic systems. OBJECTIVE: The objective of this study was to determine the effect of hindlimb unloading on the outcome of Klebsiella pneumoniae infection in mice. METHODS: Hindlimb-unloaded, hindlimb-restrained, and control mice were intraperitoneally infected with one 50% lethal dose of K pneumoniae 2 days after suspension. Mortality and bacterial load in several organs were compared among the groups. RESULTS: Unloaded mice showed significantly increased mortality and reduced mean time to death compared with that seen in the control groups. Kinetics of bacterial growth with smaller infective doses revealed that control mice were able to clear bacteria from the organs after 30 hours. In contrast, unloaded mice had continued bacterial growth at the same time point. CONCLUSION: The results of this study suggest that hindlimb unloading might enhance the dissemination of K pneumoniae, leading to increased mortality. The complex physiologic changes observed during hindlimb unloading, including stress, have a key role in the pathophysiology of this infection.

  19. Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

    PubMed Central

    Garcia, Arlene; McGlone, John J.

    2014-01-01

    Simple Summary Current guidelines suggest the use of ramps below 20° to load and unload pigs; they do not suggest the use of any specific bedding. Bedding types (nothing, feed, sand, wood shavings, and hay) were tested with four week old weaned pigs to determine which was most effective in reducing slips, falls, and vocalizations at three ramp angles, two moistures, over two seasons. Slips, falls, and vocalizations were summed to establish a scoring system to evaluate treatments. Scores increased in a linear fashion as ramp slope increased. The amount of time it took to load and unload pigs was affected by bedding type and ramp angle. Overall, the use of selected bedding types minimized slips, falls, and vocalizations and improved animal welfare. Abstract The use of non-slip surfaces during loading and unloading of weaned pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps below 20° to load and unload pigs. Three ramp angles (0°, 10° or 20°), five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay), two moistures (dry or wet bedding; >50% moisture) over two seasons (>23.9 °C summer, <23.9 °C winter) were assessed for slips/falls/vocalizations (n = 6,000 pig observations). “Score” was calculated by the sum of slips, falls, and vocalizations. With the exception of using feed as a bedding, all beddings provided some protection against elevated slips, falls, and vocalizations (P < 0.01). Providing bedding reduced (P < 0.05) scores regardless of whether the bedding was dry or wet. Scores increased as the slope increased (P < 0.01). Provision of bedding, other than feed, at slopes greater than zero, decreased slips, falls and vocalizations. The total time it took to load and unload pigs was affected by bedding type, ramp angle, and season (P < 0.05). Minimizing slips, falls, and vocalizations when loading and unloading pigs improved animal

  20. An in vivo Experimental System to Study Sugar Phloem Unloading in Ripening Grape Berries During Water Deficiency Stress

    PubMed Central

    WANG, ZHEN‐PING; DELOIRE, ALAIN; CARBONNEAU, ALAIN; FEDERSPIEL, BRIGITTE; LOPEZ, FRANÇOIS

    2003-01-01

    An in vivo experimental system—called the ‘berry‐cup’ technique—was developed to study sugar phloem unloading and the accumulation of sugar in ripening grape berries. The berry‐cup system consists of a single peeled grape berry immersed in a buffer solution in a cup prepared from a polypropylene syringe. A small cross‐incision (2 mm in length) is made on the stylar remnant of a berry during its ripening phase, the skin of the berry then being easily peeled off, exposing the dorsal vascular bundles without damaging either these or the pulp tissue of the berry. The sites of sugar phloem unloading are thus made directly accessible and may be regulated by the buffer solution. In addition, the unloaded photoassimilates are easily transported into the buffer solution in the berry‐cup. With the berry‐cup technique, it takes 60 min to purge the sugar already present in the apoplast, after which the amount of sugar in the buffer solution is a direct measure of the sugar unloading from the grape berry phloem. The optimum times for sampling were 20 or 30 min, depending on the type of experiment. Sugar phloem unloading was significantly inhibited by the inclusion of either 7·5 mm NaF or 2·5 mm PCMB in the buffer solution. This study indicates that sugar phloem unloading in ripening grape berries is via the apoplastic network and that the process requires the input of energy. The system was shown to be an appropriate experimental system with which to study sugar phloem unloading in ripening grape berries, and was applied successfully to the study of berry sugar unloaded from grapevines subjected to water stress. The results showed that water deficiency inhibits sugar unloading in grape berries. PMID:12907466

  1. Contribution of Social Isolation, Restraint, and Hindlimb Unloading to Changes in Hemodynamic Parameters and Motion Activity in Rats

    PubMed Central

    Tsvirkun, Darya; Bourreau, Jennifer; Mieuset, Aurélie; Garo, Florian; Vinogradova, Olga; Larina, Irina; Navasiolava, Nastassia; Gauquelin-Koch, Guillemette; Gharib, Claude; Custaud, Marc-Antoine

    2012-01-01

    The most accepted animal model for simulation of the physiological and morphological consequences of microgravity on the cardiovascular system is one of head-down hindlimb unloading. Experimental conditions surrounding this model include not only head-down tilting of rats, but also social and restraint stresses that have their own influences on cardiovascular system function. Here, we studied levels of spontaneous locomotor activity, blood pressure, and heart rate during 14 days under the following experimental conditions: cage control, social isolation in standard rat housing, social isolation in special cages for hindlimb unloading, horizontal attachment (restraint), and head-down hindlimb unloading. General activity and hemodynamic parameters were continuously monitored in conscious rats by telemetry. Heart rate and blood pressure were both evaluated during treadmill running to reveal cardiovascular deconditioning development as a result of unloading. The main findings of our work are that: social isolation and restraint induced persistent physical inactivity, while unloading in rats resulted in initial inactivity followed by normalization and increased locomotion after one week. Moreover, 14 days of hindlimb unloading showed significant elevation of blood pressure and slight elevation of heart rate. Hemodynamic changes in isolated and restrained rats largely reproduced the trends observed during unloading. Finally, we detected no augmentation of tachycardia during moderate exercise in rats after 14 days of unloading. Thus, we concluded that both social isolation and restraint, as an integral part of the model conditions, contribute essentially to cardiovascular reactions during head-down hindlimb unloading, compared to the little changes in the hydrostatic gradient. PMID:22768322

  2. Mechanics of load-drag-unload contact cleaning of gecko-inspired fibrillar adhesives.

    PubMed

    Abusomwan, Uyiosa A; Sitti, Metin

    2014-10-14

    Contact self-cleaning of gecko-inspired synthetic adhesives with mushroom-shaped tips has been demonstrated recently using load-drag-unload cleaning procedures similar to that of the natural animal. However, the underlying mechanics of contact cleaning has yet to be fully understood. In this work, we present a detailed experiment of contact self-cleaning that shows that rolling is the dominant mechanism of cleaning for spherical microparticle contaminants, during the load-drag-unload procedure. We also study the effect of dragging rate and normal load on the particle rolling friction. A model of spherical particle rolling on an elastomer fibrillar adhesive interface is developed and agrees well with the experimental results. This study takes us closer to determining design parameters for achieving self-cleaning fibrillar adhesives. PMID:25244526

  3. A Load-Based Multiple-Partial Unloading Micro-Indentation Technique for Mechanical Property Evaluation

    SciTech Connect

    C. Feng; J.M. Tannenbaum; B.S. Kang; M.A. Alvin

    2009-07-23

    A load-based multiple-partial unloading microindentation technique has been developed for evaluating mechanical properties of materials. Comparing to the current prevailing nano/micro-indentation methods, which require precise measurements of the indentation depth and load, the proposed technique only measures indentation load and the overall indentation displacement (i.e. including displacement of the loading apparatus). Coupled with a multiple-partial unloading procedure during the indentation process, this technique results in a load-depth sensing indentation system capable of determining Young’s modulus of metallic alloys with flat, tubular, or curved architectures. Test results show consistent and correct elastic modulus values when performing indentation tests on standard alloys such as steel, aluminum, bronze, and single crystal superalloys. The proposed micro-indentation technique has led to the development of a portable loaddepth sensing indentation system capable of on-site, in-situ material property measurement.

  4. Orbit-averaged behavior of magnetic control laws for momentum unloading

    NASA Technical Reports Server (NTRS)

    Camillo, P. J.; Markley, F. L.

    1980-01-01

    Analytical formulas are derived for orbit-averaged behavior of magnetic control laws for unloading the excess angular momentum of a spacecraft reaction wheel control system in the presence of secular environmental torques. The specific example of an axially symmetric spacecraft with an inertially fixed attitude for which the dominant environmental torque is the gravity-gradient torque is treated in detail, but extensions of the general approach to other inertially fixed and earth-pointing spacecraft are discussed. The analytical formulas are compared to detailed simulations performed for the Solar Maximum Mission spacecraft, and agreement to within 10% is found. The analytical formulas can be used in place of detailed simulations for preliminary studies, and can be used to find selected cases giving the most stringent tests of momentum unloading capability for which detailed simulations may be performed.

  5. Effects of Gravitational Mechanical Unloading in Endothelial Cells: Association between Caveolins, Inflammation and Adhesion Molecules

    PubMed Central

    Grenon, S. Marlene; Jeanne, Marion; Aguado-Zuniga, Jesus; Conte, Michael S.; Hughes-Fulford, Millie

    2013-01-01

    Mechanical forces including gravity affect endothelial cell (ECs) function, and have been implicated in vascular disease as well as physiologic changes associated with low gravity environments. The goal of this study was to investigate the impact of gravitational mechanical unloading on ECs phenotype as determined by patterns of gene expression. Human umbilical vascular endothelial cells were exposed to 1-gravity environment or mechanical unloading (MU) for 24 hours, with or without periods of mechanical loading (ML). MU led to a significant decrease in gene expression of several adhesion molecules and pro-inflammatory cytokines. On the contrary, eNOS, Caveolin-1 and -2 expression were significantly increased with MU. There was a decrease in the length and width of the cells with MU. Addition of ML during the MU period was sufficient to reverse the changes triggered by MU. Our results suggest that gravitational loading could dramatically affect vascular endothelial cell function. PMID:23511048

  6. Work capacity and metabolic and morphologic characteristics of the human quadriceps muscle in response to unloading

    NASA Technical Reports Server (NTRS)

    Berg, H. E.; Dudley, G. A.; Hather, B.; Tesch, P. A.

    1993-01-01

    The response of skeletal muscle to unweighting was studied in six healthy males who were subjected to four weeks of lowerlimb suspension. They performed three bouts of 30 consecutive maximal concentric knee extensions, before unloading and the day after (POST 1), 4 days after (POST 2) and 7 weeks after (REC) resumed weight-bearing. Peak torque of each contraction was recorded and work was calculated as the mean of the average peak torque for the three bouts and fatigability was measured as the decline in average peak torque over bouts. Needle biopsies were obtained from m. vastus lateralis of each limb before and at POST 1. Muscle fibre type composition and area, capillarity and the enzyme activities of citrate synthase (CS) and phosphofructokinase (PFK) were subsequently analysed. Mean average peak torque for the three bouts at POST1, POST2 and REC was reduced (P < 0.05) by 17, 13 and 7%, respectively. Fatigability was greater (P < 0.05) at POST2 than before unloading. Type I, IIA and IIB percentage, Type I and II area and capillaries per fibre of Type I and II did not change (P > 0.05) in response to unloading. The activity of CS, but not PFK, decreased (P < 0.05) after unloading. The weight-bearing limb showed no changes in the variables measured. The results of this study suggest that this human lowerlimb suspension model produces substantial impairments of work and oxidative capacity of skeletal muscle. The performance decrements are most likely induced by lack of weight-bearing.

  7. Site- and compartment-specific changes in bone with hindlimb unloading in mature adult rats

    NASA Technical Reports Server (NTRS)

    Bloomfield, S. A.; Allen, M. R.; Hogan, H. A.; Delp, M. D.

    2002-01-01

    The purpose of this study was to examine site- and compartment-specific changes in bone induced by hindlimb unloading (HU) in the mature adult male rat (6 months old). Tibiae, femora, and humeri were removed after 14, 21, and 28 days of HU for determination of bone mineral density (BMD) and geometry by peripheral quantitative computed tomography (pQCT), mechanical properties, and bone formation rate (BFR), and compared with baseline (0 day) and aging (28 day) controls. HU resulted in 20%-21% declines in cancellous BMD at the proximal tibia and femoral neck after 28 day HU vs. 0 day controls (CON). Cortical shell BMD at these sites was greater (by 4%-6%) in both 28 day HU and 28 day CON vs. 0 day CON animals, and nearly identical to that gain seen in the weight-bearing humerus. Mechanical properties at the proximal tibia exhibited a nonsignificant decline after HU vs. those of 0 day CON rats. At the femoral neck, a 10% decrement was noted in ultimate load in 28 day HU rats vs. 28 day CON animals. Middiaphyseal tibial bone increased slightly in density and area during HU; no differences in structural and material properties between 28 day HU and 28 day CON rats were noted. BFR at the tibial midshaft was significantly lower (by 90%) after 21 day HU vs. 0 day CON; this decline was maintained throughout 28 day HU. These results suggest there are compartment-specific differences in the mature adult skeletal response to hindlimb unloading, and that the major impact over 28 days of unloading is on cancellous bone sites. Given the sharp decline in BFR for midshaft cortical bone, it appears likely that deficits in BMD, area, or mechanical properties would develop with longer duration unloading.

  8. Possible mechanism for changes in glycogen metabolism in unloaded soleus muscle

    NASA Technical Reports Server (NTRS)

    Henriksen, E. J.; Tischler, M. E.

    1985-01-01

    Carbohydrate metabolism has been shown to be affected in a number of ways by different models of hypokinesia. In vivo glycogen levels in the soleus muscle are known to be increased by short-term denervation and harness suspension. In addition, exposure to 7 days of hypogravity also caused a dramatic increase in glycogen concentration in this muscle. The biochemical alterations caused by unloading that may bring about these increases in glycogen storage in the soleus were sought.

  9. Calpain-dependent regulation of the skeletal muscle atrophy following unloading.

    PubMed

    Shenkman, Boris S; Belova, Svetlana P; Lomonosova, Yulia N; Kostrominova, Tatiana Y; Nemirovskaya, Tatyana L

    2015-10-15

    Unloading causes rapid skeletal muscle atrophy due to increased protein degradation via activation of calpains and decreased protein synthesis. Our study elucidated role of calpain-1 in the regulation of ubiquitin proteasome pathway (UPP) and anabolic processes mediated by Akt-mTOR-p70S6K and MAPK-Erk (p90RSK) signaling. We hypothesized that blocking calpain will inhibit activation of UPP and decrease protein degradation resulting in reduction of unloading-induced skeletal muscle atrophy. Rats were divided into three groups: non-treated control (C), three day hindlimb suspension with (HSPD) or without (HS) treatment with calpain inhibitor PD150606. When compared with control PD150606 treatment during unloading: 1) attenuated loss of muscle mass, 2) prevented accumulation of calpain-1 (1.8-fold in HS vs 1.3-fold in HSPD) and ubiquitin (2.3-fold in HS vs 0.7-fold in HSPD) mRNA and ubiquitinated proteins (1.6-fold in HS vs 0.8-fold in HSPD), 3) prevented decrease in the pAkt (0.4-fold in HS vs 1-fold in HSPD) and pFOXO3 (0.2-fold in HS vs 1.2-fold in HSPD) levels, 4) prevented increase in MAFbx (3.8-fold in HS vs 1.3-fold in HSPD) and eEF2k (1.8-fold in HS vs 0.6-fold in HSPD) mRNA. Our study indicates that blocking of calpain during unloading decreases skeletal muscle atrophy by inhibiting UPP activation and preserving anabolic signaling. PMID:26297661

  10. Effects of skeletal unloading on the vasomotor properties of the rat femur principal nutrient artery

    PubMed Central

    Prisby, Rhonda D.; Behnke, Bradley J.; Allen, Matthew R.

    2015-01-01

    Spaceflight and prolonged bed rest induce deconditioning of the cardiovascular system and bone loss. Previous research has shown declines in femoral bone and marrow perfusion during unloading and with subsequent reloading in hindlimb-unloaded (HU) rats, an animal model of chronic disuse. We hypothesized that the attenuated bone and marrow perfusion may result from altered vasomotor properties of the bone resistance vasculature. Therefore, the purpose of this study was to determine the effects of unloading on the vasoconstrictor and vasodilator properties of the femoral principal nutrient artery (PNA), the main conduit for blood flow to the femur, in 2 wk HU and control (CON) rats. Vasoconstriction of the femoral PNA was assessed in vitro using norepinephrine, phenylephrine, clonidine, KCl, endothelin-1, arginine vasopressin, and myogenic responsiveness. Vasodilation through endothelium-dependent [acetylcholine, bradykinin, and flow-mediated dilation (FMD)] and endothelium-independent mechanisms [sodium nitroprusside (SNP) and adenosine] were also determined. Vasoconstrictor responsiveness of the PNA from HU rats was not enhanced through any of the mechanisms tested. Endothelium-dependent vasodilation to acetylcholine (CON, 86 ± 3%; HU, 48 ± 7% vasodilation) and FMD (CON, 61 ± 9%; HU, 11 ± 11% vasodilation) were attenuated in PNAs from HU rats, while responses to bradykinin were not different between groups. Endothelium-independent vasodilation to SNP and adenosine were not different between groups. These data indicate that unloading-induced decrements in bone and marrow perfusion and increases in vascular resistance are not the result of enhanced vasoconstrictor responsiveness of the bone resistance arteries but are associated with reductions in endothelium-dependent vasodilation. PMID:25635000

  11. Differences in Cartilage Repair between Loading and Unloading Environments in the Rat Knee

    PubMed Central

    Matsuzaki, Taro; Yoshida, Shinya; Kitade, Ippei; Hoso, Masahiro

    2014-01-01

    We investigated the histopathological and immunohistochemical effects of loading on cartilage repair in rat full-thickness articular cartilage defects. A total of 40 male 9-week-old Wistar rats were studied. Full-thickness articular cartilage defects were created over the capsule at the loading portion in the medial condyle of the femur. Twenty rats were randomly allocated into each of the 2 groups: a loading group and a unloading group. Twenty rats from these 2 groups were later randomly allocated to each of the 2 groups for evaluation at 1 and 2 weeks after surgery. At the end of each period, knee joints were examined histopathologically and immunohistochemically. In both groups at 1 and 2 weeks, the defects were filled with a mixture of granulation tissue and some remnants of hyaline cartilage. The repair tissue was not stained with toluidine blue in both groups. Strong staining of type I collagen was observed in the repair tissue of both groups. The area stained with type I collagen was smaller in the unloading group than in the loading groups, and the stained area was smaller at 2 weeks than at 1 week. In the staining for type II collagen, apparent staining of type II collagen was observed in the repair tissue of both groups at 1 week. At 2 weeks, there was a tendency toward a higher degree of apparent staining in the loading group than in the unloading group. Accordingly, these results indicated that loading and unloading in the early phase of cartilage repair have both merits and demerits. PMID:25792905

  12. Non-random nectar unloading interactions between foragers and their receivers in the honeybee hive

    NASA Astrophysics Data System (ADS)

    Goyret, Joaquín; Farina, Walter M.

    2005-09-01

    Nectar acquisition in the honeybee Apis mellifera is a partitioned task in which foragers gather nectar and bring it to the hive, where nest mates unload via trophallaxis (i.e. mouth-to-mouth transfer) the collected food for further storage. Because forager mates exploit different feeding places simultaneously, this study addresses the question of whether nectar unloading interactions between foragers and hive-bees are established randomly, as it is commonly assumed. Two groups of foragers were trained to exploit a different scented food source for 5 days. We recorded their trophallaxes with hive-mates, marking the latter ones according to the forager group they were unloading. We found non-random probabilities for the occurrence of trophallaxes between experimental foragers and hive-bees, instead, we found that trophallactic interactions were more likely to involve groups of individuals which had formerly interacted orally. We propose that olfactory cues present in the transferred nectar promoted the observed bias, and we discuss this bias in the context of the organization of nectar acquisition: a partitioned task carried out in a decentralized insect society.

  13. Mechanics unloading analysis and experimentation of a new type of parallel biomimetic shoulder complex

    NASA Astrophysics Data System (ADS)

    Hou, Yulei; Li, Zhisen; Wang, Yi; Zhang, Wenwen; Zeng, Daxing; Zhou, Yulin

    2016-06-01

    The structure design for high ratio of carrying capacity to deadweight is one of the challenges for the bionic mechanism, while the problem concerning high carrying capacity has not yet be solved for the existing shoulder complex. A new type biomimetic shoulder complex, which adopts 3-PSS/S(P for prismatic pair, S for spherical pair) spherical parallel mechanism (SPM), is proposed. The static equilibrium equations of each component are established by using the vector method and the equations for constrain forces with certain load are solved. Then the constrain force on the middle limb and that on the side limbs are compared in order to verify the unloading performance of the mechanism. In addition, the prototype mechanism of the shoulder complex is developed, and the force feedback experiment is conducted to verify the static analysis, which indicates that the middle limb suffers most of the external force and the effect of mechanics unloading is achieved. The 3-PSS/S spherical parallel mechanism is presented for the shoulder complex, and the realization of mechanics unloading is benefit for the improvement of the carrying capacity of the shoulder complex.

  14. Biaxial unloading and springback behavior of dual-phase DP590 steel using cruciform specimens

    NASA Astrophysics Data System (ADS)

    Korkolis, Yannis P.; Deng, Nengxiu; Kuwabara, Toshihiko

    2013-12-01

    The unloading behavior of a dual-phase steel (DP590) from a biaxial state of stress was probed using a newly-designed cruciform specimen. The specimen was designed to develop uniform and relatively large plastic strains (over 15% equivalent logarithmic plastic strain) in the gage section, before failure. Nine radial loading paths in the 1st quadrant of the plane stress space were probed. The experiments involved repeated loading and unloading up to failure. At every unloading, the initial response was found to agree with the linear, orthotropically elastic response of the undeformed material. This first linear response was followed by a second one, at a reduced slope. Beyond that, the recorded response was fully non-linear. The same sequence of events was observed during each reloading. The biaxial non-linear strain recovery components ɛxnl and ɛynl were measured to be on average approximately 11% of the elastic strains ɛxe and ɛye, respectively. This ratio was found to increase with plastic deformation. Subsequently, these biaxial experiments were used to calibrate the Yld2000-2D yield function.

  15. A Mathematical Model of Oxygen Transport in Skeletal Muscle During Hindlimb Unloading

    NASA Technical Reports Server (NTRS)

    Causey, Laura; Lewandowski, Beth E.; Weinbaum, Sheldon

    2014-01-01

    During hindlimb unloading (HU) dramatic fluid shifts occur within minutes of the suspension, leading to a less precise matching of blood flow to O2 demands of skeletal muscle. Vascular resistance directs blood away from certain muscles, such as the soleus (SOL). The muscle volume gradually reduces in these muscles so that eventually the relative blood flow returns to normal. It is generally believed that muscle volume change is not due to O2 depletion, but a consequence of disuse. However, the volume of the unloaded rat muscle declines over the course of weeks, whereas the redistribution of blood flow occurs immediately. Using a Krogh Cylinder Model, the distribution of O2 was predicted in two skeletal muscles: SOL and gastrocnemius (GAS). Effects of the muscle blood flow, volume, capillary density, and O2 uptake, are included to calculate the pO2 at rest and after 10 min and 15 days of unloading. The model predicts that 32 percent of the SOL muscle tissue has a pO2 1.25 mm Hg within 10 min, whereas the GAS maintains normal O2 levels, and that equilibrium is reached only as the SOL muscle cells degenerate. The results provide evidence that there is an inadequate O2 supply to the mitochondria in the SOL muscle after 10 min HU.

  16. Gravitational force modulates G2/M phase exit in mechanically unloaded myoblasts

    PubMed Central

    Benavides Damm, Tatiana; Franco-Obregón, Alfredo; Egli, Marcel

    2013-01-01

    Prolonged spaceflight gives rise to muscle loss and reduced strength, a condition commonly referred to as space atrophy. During exposure to microgravity, skeletal muscle myoblasts are mechanically unloaded and respond with attenuated cell proliferation, slowed cell cycle progression, and modified protein expression. To elucidate the underlying mechanisms by which muscle mass declines in response to prolonged microgravity exposure, we grew C2C12 mouse muscle cells under conditions of simulated microgravity (SM) and analyzed their proliferative capacity, cell cycle progression, and cyclin B and D expression. We demonstrated that the retarded cell growth observed in SM was correlated with an approximate 16 h delay in G2/M phase progression, where cells accumulated specifically between the G2 checkpoint and the onset of anaphase, concomitantly with a positive expression for cyclin B. The effect was specific for gravitational mechanical unloading as cells grown under conditions of hypergravity (HG, 4 g) for similar durations of time exhibited normal proliferation and normal cell cycle progression. Our results show that SM and HG exert phenomenological distinct responses over cell cycle progression. The deficits of SM can be restored by terrestrial gravitational force, whereas the effects of HG are indistinguishable from the 1 g control. This suggests that the mechanotransduction apparatus of cells responds differently to mechanical unloading and loading. PMID:23974110

  17. Increased GABA(A) inhibition of the RVLM after hindlimb unloading in rats

    NASA Technical Reports Server (NTRS)

    Moffitt, Julia A.; Heesch, Cheryl M.; Hasser, Eileen M.

    2002-01-01

    Attenuated baroreflex-mediated increases in renal sympathetic nerve activity (RSNA) in hindlimb unloaded (HU) rats apparently are due to changes within the central nervous system. We hypothesized that GABA(A) receptor-mediated inhibition of the rostral ventrolateral medulla (RVLM) is increased after hindlimb unloading. Responses to bilateral microinjection of the GABA(A) antagonist (-)-bicuculline methiodide (BIC) into the RVLM were examined before and during caudal ventrolateral medulla (CVLM) inhibition in Inactin-anesthetized control and HU rats. Increases in mean arterial pressure (MAP), heart rate (HR), and RSNA in response to BIC in the RVLM were significantly enhanced in HU rats. Responses to bilateral CVLM blockade were not different. When remaining GABA(A) inhibition in the RVLM was blocked by BIC during CVLM inhibition, the additional increases in MAP and RSNA were significantly greater in HU rats. These data indicate that GABA(A) receptor-mediated inhibition of RVLM neurons is augmented after hindlimb unloading. Effects of input from the CVLM were unaltered. Thus, after cardiovascular deconditioning in rodents, the attenuated increase in sympathetic nerve activity in response to hypotension is associated with greater GABA(A) receptor-mediated inhibition of RVLM neurons originating at least in part from sources other than the CVLM.

  18. Nerve-responsive troponin I slow promoter does not respond to unloading

    NASA Technical Reports Server (NTRS)

    Criswell, D. S.; Hodgson, V. R.; Hardeman, E. C.; Booth, F. W.

    1998-01-01

    We examined the regulation of the troponin I slow (TnIs) promoter during skeletal muscle unloading-induced protein isoform transition, by using a transgenic mouse line harboring the -4,200 to +12 base pairs region of the human TnIs promoter. Eighteen female transgenic mice ( approximately 30 g body mass) were randomly divided into two groups: weight-bearing (WB) controls (n = 9) and hindlimb unloaded (HU; n = 9). The HU mice were tail suspended for 7 days. Body mass was unchanged in the WB group but was reduced (-6%; P < 0.05) after the HU treatment. Absolute soleus muscle mass (-25%) and soleus mass relative to body mass (-16%) were both lower (P < 0.05) in the HU group compared with the WB mice. Northern blot analyses indicate that 7 days of HU result in a 64% decrease (P < 0.05) in the abundance of endogenous TnIs mRNA (microg/mg muscle) in the mouse soleus. Furthermore, there is a trend for the abundance of the fast troponin I mRNA to be increased (+34%). Analysis of transgenic chloramphenicol acetyltransferase activity in the soleus muscle revealed no difference (P > 0.05) between WB and HU groups. We conclude that additional elements are necessary for the TnIs gene to respond to an unloading-induced, slow-to-fast isoform transition stimulus.

  19. EUK-134 ameliorates nNOSμ translocation and skeletal muscle fiber atrophy during short-term mechanical unloading

    PubMed Central

    Kunst, Mary; Hord, Jeff M.; Lee, Yang; Joshi, Kumar; Botchlett, Rachel E.; Ramirez, Angelo; Martinez, Daniel A.

    2014-01-01

    Reduced mechanical loading during bedrest, spaceflight, and casting, causes rapid morphological changes in skeletal muscle: fiber atrophy and reduction of slow-twitch fibers. An emerging signaling event in response to unloading is the translocation of neuronal nitric oxide synthase (nNOSμ) from the sarcolemma to the cytosol. We used EUK-134, a cell-permeable mimetic of superoxide dismutase and catalase, to test the role of redox signaling in nNOSμ translocation and muscle fiber atrophy as a result of short-term (54 h) hindlimb unloading. Fischer-344 rats were divided into ambulatory control, hindlimb-unloaded (HU), and hindlimb-unloaded + EUK-134 (HU-EUK) groups. EUK-134 mitigated the unloading-induced phenotype, including muscle fiber atrophy and muscle fiber-type shift from slow to fast. nNOSμ immunolocalization at the sarcolemma of the soleus was reduced with HU, while nNOSμ protein content in the cytosol increased with unloading. Translocation of nNOS from the sarcolemma to cytosol was virtually abolished by EUK-134. EUK-134 also mitigated dephosphorylation at Thr-32 of FoxO3a during HU. Hindlimb unloading elevated oxidative stress (4-hydroxynonenal) and increased sarcolemmal localization of Nox2 subunits gp91phox (Nox2) and p47phox, effects normalized by EUK-134. Thus, our findings are consistent with the hypothesis that oxidative stress triggers nNOSμ translocation from the sarcolemma and FoxO3a dephosphorylation as an early event during mechanical unloading. Thus, redox signaling may serve as a biological switch for nNOS to initiate morphological changes in skeletal muscle fibers. PMID:24477538

  20. Effect of Proton Irradiation Followed by Hindlimb Unloading on Bone in Mature Mice: A Model of Long-Duration Spaceflight

    PubMed Central

    Lloyd, Shane A.; Bandstra, Eric R.; Willey, Jeffrey S.; Riffle, Stephanie E.; Tirado-Lee, Leidamarie; Nelson, Gregory A.; Pecaut, Michael J.; Bateman, Ted A.

    2012-01-01

    Bone loss associated with microgravity unloading is well documented; however, the effects of spaceflight-relevant types and doses of radiation on the skeletal system are not well defined. In addition, the combined effect of unloading and radiation has not received much attention. In the present study, we investigated the effect of proton irradiation followed by mechanical unloading via hindlimb suspension (HLS) in mice. Sixteen-week-old female C57BL/6 mice were either exposed to 1 Gy of protons or a sham irradiation procedure (n=30/group). One day later, half of the mice in each group were subjected to four weeks of HLS or normal loading conditions. Radiation treatment alone (IRR) resulted in approximately 20% loss of trabecular bone volume fraction (BV/TV) in the tibia and femur, with no effect in the cortical bone compartment. Conversely, unloading induced substantially greater loss of both trabecular bone (60–70% loss of BV/TV) and cortical bone (approximately 20% loss of cortical bone volume) in both the tibia and femur, with corresponding decreases in cortical bone strength. Histological analyses and serum chemistry data demonstrated increased levels of osteoclast-mediated bone resorption in unloaded mice, but not IRR. HLS+IRR mice generally experienced greater loss of trabecular bone volume fraction, connectivity density, and trabecular number than either unloading or irradiation alone. Although the duration of unloading may have masked certain effects, the skeletal response to irradiation and unloading appears to be additive for certain parameters. Appropriate modeling of the environmental challenges of long duration spaceflight will allow for a better understanding of the underlying mechanisms mediating spaceflight-associated bone loss and for the development of effective countermeasures. PMID:22789684

  1. Prevention of muscle fibers atrophy during gravitational unloading: The effect of L-arginine administration

    NASA Astrophysics Data System (ADS)

    Kartashkina, N.; Lomonosova, Y.; Shevchenko, T. F.; Bugrova, A. E.; Turtikova, O. V.; Kalamkarov, G. R.; Nemirovskaya, T. L.

    2011-05-01

    Gravitational unloading results in pronounced atrophy of m.soleus. Probably, the output of NO is controlled by the muscle activity. We hypothesized that NO may be involved in the protein metabolism and increase of its concentration in muscle can prevent atrophic changes induced by gravitational unloading. In order to test the hypothesis we applied NO donor L-arginine during gravitational unloading. 2.5-month-old male Wistar rats weighing 220-230g were divided into sedentary control group (CTR, n=7), 14-day hindlimb suspension (HS, n=7), 14 days of hindlimb suspension+ L-arginine (HSL, n=7) (with a daily supplementation of 500 mg/kg wt L-arginine) and 14 days of hindlimb suspension+ L-NAME (HSN, n=7) (90 mg/kg wt during 14 days). Cross sectional area (CSA) of slow twitch (ST) and fast twitch (FT) soleus muscle fibers decreased by 45% and 28% in the HS group ( p<0.05) and 40% and 25% in the HSN group, as compared to the CTR group ( p<0.05), respectively. CSA of ST and FT muscle fibers were 25% and 16% larger in the HSL group in comparison with the HS group ( p<0.05), respectively. The atrophy of FT muscle fibers in the HSL group was completely prevented since FT fiber CSA had no significant differences from the CTR group. In HS group, the percentage of fibers revealing either gaps/disruption of the dystrophin layer of the myofiber surface membrane increased by 27% and 17%, respectively, as compared to the controls (CTR group, p<0.05). The destructions in dystrophin layer integrity and reductions of desmin content were significantly prevented in HSL group. NO concentration decreased by 60% in the HS group (as well as HSN group) and at the same time no changes were detectable in the HSL group. This fact indicates the compensation of NO content in the unloaded muscle under L-arginine administration. The levels of atrogin-1 mRNA were considerably altered in suspended animals (HS group: plus 27%, HSL group: minus 13%) as compared to the control level. Conclusion: L

  2. Transforming growth factor beta2 inhibits adipocyte differentiation induced by skeletal unloading in rat bone marrow stroma.

    PubMed

    Ahdjoudj, Souhila; Lasmoles, Françoise; Holy, Xavier; Zerath, Erik; Marie, Pierre J

    2002-04-01

    Skeletal unloading induced by hindlimb suspension in rats reduces bone formation and induces osteopenia, but its effect on adipogenesis is unknown. We assessed the effects of unloading and transforming growth factor (TGF) beta2 on bone marrow stromal cell adipocyte differentiation in relation with osteoblast differentiation. Skeletal unloading rapidly (4-7 days) decreased osteoblast transcription factor Runx2, osteocalcin (OC), and type I collagen messenger RNA (mRNA) levels and reduced bone formation in the long bone metaphysis. Conversely, unloading increased expression of the adipocyte transcription factor peroxisome proliferator-activated receptor gamma2 (PPARgamma2) at 4 days and increased expression of the adipocyte differentiation genes lipoprotein lipase (LPL) and aP2 in the bone marrow stroma at 7 days. Consistently, unloading increased the number and volume of adipocytes in the bone marrow stroma. Continuous (0-7 days) and late (4-7 days) treatments with TGF-beta2 corrected the abnormal expression of Cbfa1/Runx2, OC, and type I collagen mRNAs and normalized bone formation in unloaded metaphyseal bone. Moreover, both TGF-beta2 treatments decreased PPARy2 and C/EBPalpha mRNA levels at 4 days and normalized aP2 and LPL expression and adipocyte number and volume at 7 days. These results show that skeletal unloading increases adipocyte differentiation concomitantly with inhibition of osteoblast differentiation. These abnormalities are prevented and reversed by TGF-beta2, suggesting a role for TGF-beta in the control of adipogenic differentiation in the bone marrow stroma. PMID:11918224

  3. Impaired Axonal Na+ Current by Hindlimb Unloading: Implication for Disuse Neuromuscular Atrophy

    PubMed Central

    Banzrai, Chimeglkham; Nodera, Hiroyuki; Kawarai, Toshitaka; Higashi, Saki; Okada, Ryo; Mori, Atsuko; Shimatani, Yoshimitsu; Osaki, Yusuke; Kaji, Ryuji

    2016-01-01

    This study aimed to characterize the excitability changes in peripheral motor axons caused by hindlimb unloading (HLU), which is a model of disuse neuromuscular atrophy. HLU was performed in normal 8-week-old male mice by fixing the proximal tail by a clip connected to the top of the animal's cage for 3 weeks. Axonal excitability studies were performed by stimulating the sciatic nerve at the ankle and recording the compound muscle action potential (CMAP) from the foot. The amplitudes of the motor responses of the unloading group were 51% of the control amplitudes [2.2 ± 1.3 mV (HLU) vs. 4.3 ± 1.2 mV (Control), P = 0.03]. Multiple axonal excitability analysis showed that the unloading group had a smaller strength-duration time constant (SDTC) and late subexcitability (recovery cycle) than the controls [0.075 ± 0.01 (HLU) vs. 0.12 ± 0.01 (Control), P < 0.01; 5.4 ± 1.0 (HLU) vs. 10.0 ± 1.3 % (Control), P = 0.01, respectively]. Three weeks after releasing from HLU, the SDTC became comparable to the control range. Using a modeling study, the observed differences in the waveforms could be explained by reduced persistent Na+ currents along with parameters related to current leakage. Quantification of RNA of a SCA1A gene coding a voltage-gated Na+ channel tended to be decreased in the sciatic nerve in HLU. The present study suggested that axonal ion currents are altered in vivo by HLU. It is still undetermined whether the dysfunctional axonal ion currents have any pathogenicity on neuromuscular atrophy or are the results of neural plasticity by atrophy. PMID:26909041

  4. Project UM-HAUL: A self-unloading reusable lunar lander

    NASA Astrophysics Data System (ADS)

    The establishment of a lunar base is technologically and financially challenging. Given the necessary resources and political support, it can be done. In addition to the geopolitical obstacles, however, there are logistical problems involved in establishing such bases that can only be overcome with the acquisition of a significant transportation and communications network in the Earth-Moon spatial region. Considering the significant number of payloads that will be required in this process, the mass-specific cost of launching these payloads, and the added risk and cost of human presence in space, it is clearly desirable to automate major parts of such an operation. One very costly and time-consuming factor in this picture is the delivery of payloads to the Moon. Foreseeable payloads would include atmospheric modules, inflatable habitat kits, energy and oxygen plant elements, ground vehicles, laboratory modules, crew supplies, etc. The duration of high-risk human presence on the Moon could be greatly reduced if all such payloads were delivered to the prospective base site in advance of crew arrival. In this view, the idea of a 'Self-Unloading Reusable Lunar Lander' (SURLL) arises naturally. The general scenario depicts the lander being brought to low lunar orbit (LLO) from Earth atop a generic Orbital Transfer Vehicle (OTV). From LLO, the lander shuttles payloads down to the lunar surface, where, by means of some resident, detachable unloading device, it deploys the payloads and returns to orbit. The general goal is for the system to perform with maximum payload capability, automation, and reliability, while also minimizing environmental hazards, servicing needs, and mission costs. Our response to this demand is UM-HAUL, or the UnManned Heavy pAyload Unloader and Lander. The complete study includes a system description, along with a preliminary cost analysis and a design status assessment.

  5. Vasopressin responses to unloading arterial baroreceptors during cardiac nerve blockade in conscious dogs

    NASA Technical Reports Server (NTRS)

    O'Donnell, C. P.; Keil, L. C.; Thrasher, T. N.

    1992-01-01

    We examined the relative contributions of afferent input from the heart and from arterial baroreceptors in the stimulation of arginine vasopressin (AVP) secretion in response to hypotension caused by thoracic inferior vena caval constriction (TIVCC). Afferent input from cardiac receptors was reversibly blocked by infusing 2% procaine into the pericardial space to anesthetize the cardiac nerves. Acute cardiac nerve blockade (CNB) alone caused a rise in mean arterial pressure (MAP) of 24 +/- 3 mmHg but no change in plasma AVP. If the rise in MAP was prevented by TIVCC, plasma AVP increased by 39 +/- 15 pg/ml, and if MAP was allowed to increase and then was forced back to control by TIVCC, plasma AVP increased by 34 +/- 15 pg/ml. Thus the rise in MAP during CNB stimulated arterial baroreceptors, which in turn compensated for the loss of inhibitory input from cardiac receptors on AVP secretion. These results indicate that the maximum secretory response resulting from complete unloading of cardiac receptors at a normal MAP results in a mean increase in plasma AVP of 39 pg/ml in this group of dogs. When MAP was reduced 25% below control levels (from 95 +/- 5 to 69 +/- 3 mmHg) by TIVCC during pericardial saline infusion, plasma AVP increased by 79 +/- 42 pg/ml. However, the same degree of hypotension during CNB (MAP was reduced from 120 +/- 5 to 71 +/- 3 mmHg) led to a greater (P less than 0.05) increase in plasma AVP of 130 +/- 33 pg/ml. Because completely unloading cardiac receptors can account for an increase of only 39 pg/ml on average in this group of dogs, the remainder of the increase in plasma AVP must be due to other sources of stimulation. We suggest that the principal stimulus to AVP secretion after acute CNB in these studies arises from unloading the arterial baroreceptors.

  6. Reloading partly recovers bone mineral density and mechanical properties in hind limb unloaded rats

    NASA Astrophysics Data System (ADS)

    Zhao, Fan; Li, Dijie; Arfat, Yasir; Chen, Zhihao; Liu, Zonglin; Lin, Yu; Ding, Chong; Sun, Yulong; Hu, Lifang; Shang, Peng; Qian, Airong

    2014-12-01

    Skeletal unloading results in decreased bone formation and bone mass. During long-term space flight, the decreased bone mass is impossible to fully recover. Therefore, it is necessary to develop the effective countermeasures to prevent spaceflight-induced bone loss. Hindlimb Unloading (HLU) simulates effects of weightlessness and is utilized extensively to examine the response of musculoskeletal systems to certain aspects of space flight. The purpose of this study is to investigate the effects of a 4-week HLU in rats and subsequent reloading on the bone mineral density (BMD) and mechanical properties of load-bearing bones. After HLU for 4 weeks, the rats were then subjected to reloading for 1 week, 2 weeks and 3 weeks, and then the BMD of the femur, tibia and lumbar spine in rats were assessed by dual energy X-ray absorptiometry (DXA) every week. The mechanical properties of the femur were determined by three-point bending test. Dry bone and bone ash of femur were obtained through Oven-Drying method and were weighed respectively. Serum alkaline phosphatase (ALP) and serum calcium were examined through ELISA and Atomic Absorption Spectrometry. The results showed that 4 weeks of HLU significantly decreased body weight of rats and reloading for 1 week, 2 weeks or 3 weeks did not recover the weight loss induced by HLU. However, after 2 weeks of reloading, BMD of femur and tibia of HLU rats partly recovered (+10.4%, +2.3%). After 3 weeks of reloading, the reduction of BMD, energy absorption, bone mass and mechanical properties of bone induced by HLU recovered to some extent. The changes in serum ALP and serum calcium induced by HLU were also recovered after reloading. Our results indicate that a short period of reloading could not completely recover bone after a period of unloading, thus some interventions such as mechanical vibration or pharmaceuticals are necessary to help bone recovery.

  7. Development of a functional food or drug against unloading-mediated muscle atrophy

    NASA Astrophysics Data System (ADS)

    Nikawa, Takeshi; Nakao, Reiko; Kagawa, Sachiko; Yamada, Chiharu; Abe, Manami; Tamura, Seiko; Kohno, Shohei; Sukeno, Akiko; Hirasaka, Katsuya; Okumura, Yuushi; Ishidoh, Kazumi

    The ubiquitin-proteasome pathway is a primary regulator of muscle protein turnover, providing a mechanism for selective degradation of regulatory and structural proteins. This pathway is constitutively active in muscle fibers and mediates both intracellular signaling events and normal muscle protein turnover. However, conditions of decreased muscle use, so called unloading, remarkably stimulate activity of this pathway, resulting in loss of muscle protein. In fact, we previously reported that expression of several ubiquitin ligase genes, such as MuRF-1, Cbl-b, and Siah-1A, which are rate-limiting enzymes of the ubiquitin-proteasome proteolytic pathway, are significantly up-regulated in rat skeletal muscle during spaceflight. Moreover, we found that Cbl-b-mediated ubiquitination and degradation of IRS-1, an important intermediates of IGF-1 signal transduction, contributes to muscle atrophy during unloading. Therefore, we hypothesized that inhibition of Cbl-b-mediated ubiquitination and degradation of IRS-1 leads to prevention of muscle atrophy during unloading. In this study, we aimed to evaluate oligopeptide as an inhibitor against ubiquitination of IRS-1 by Cbl-b. We synthesized various oligopeptides that may competitively inhibit the binding of Cbl-b to IRS-1 on the basis of their structures and screened inhibitory effects of these synthesized oligopeptides on Cbl-b-mediated ubiquitination of IRS-1 using in vitro ubiquitination systems. We found that two synthetic oligopeptides with specific amino acid sequences effectively inhibited interaction with Cbl-b and IRS-1, resulting in decreased ubiquitination and degradation of IRS-1 (Patent pending). In contrast, we also found inhibitory activity against Cbl-b-mediated ubiquitination of IRS-1 in soy protein-derived oligopeptides, whereas their inhibitory effects were weaker than those of synthetic oligopeptides. Our results suggest that specific oligopeptides may be available as a functional food against the muscle

  8. Project UM-HAUL: A self-unloading reusable lunar lander

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The establishment of a lunar base is technologically and financially challenging. Given the necessary resources and political support, it can be done. In addition to the geopolitical obstacles, however, there are logistical problems involved in establishing such bases that can only be overcome with the acquisition of a significant transportation and communications network in the Earth-Moon spatial region. Considering the significant number of payloads that will be required in this process, the mass-specific cost of launching these payloads, and the added risk and cost of human presence in space, it is clearly desirable to automate major parts of such an operation. One very costly and time-consuming factor in this picture is the delivery of payloads to the Moon. Foreseeable payloads would include atmospheric modules, inflatable habitat kits, energy and oxygen plant elements, ground vehicles, laboratory modules, crew supplies, etc. The duration of high-risk human presence on the Moon could be greatly reduced if all such payloads were delivered to the prospective base site in advance of crew arrival. In this view, the idea of a 'Self-Unloading Reusable Lunar Lander' (SURLL) arises naturally. The general scenario depicts the lander being brought to low lunar orbit (LLO) from Earth atop a generic Orbital Transfer Vehicle (OTV). From LLO, the lander shuttles payloads down to the lunar surface, where, by means of some resident, detachable unloading device, it deploys the payloads and returns to orbit. The general goal is for the system to perform with maximum payload capability, automation, and reliability, while also minimizing environmental hazards, servicing needs, and mission costs. Our response to this demand is UM-HAUL, or the UnManned Heavy pAyload Unloader and Lander. The complete study includes a system description, along with a preliminary cost analysis and a design status assessment.

  9. Isometric resistance exercise fails to counteract skeletal muscle atrophy processes during the initial stages of unloading.

    PubMed

    Haddad, F; Adams, G R; Bodell, P W; Baldwin, K M

    2006-02-01

    This study tested the hypothesis that an isometric resistance training paradigm targeting the medial gastrocnemius of adult rodents is effective in preventing muscle atrophy during the early stages of hindlimb unloading by maintaining normal activation of the insulin receptor substrate-1 (IRS-1)/phosphoinositide-3 kinase (PI3K)/Akt signaling pathway. This pathway has been shown to simultaneously create an anabolic response while inhibiting processes upregulating catabolic processes involving expression of key enzymes in the ubiquitination of proteins for degradation. The findings show that during the 5 days of unloading 1) absolute medial gastrocnemius muscle weight reduction occurred by approximately 20%, but muscle weight corrected to body weight was not different from normal weight-bearing controls (P < 0.05); 2) normalized myofibril fraction concentration and content were decreased; and 3) a robust isometric training program, known to induce a hypertrophy response, failed to maintain the myofibril protein content. This response occurred despite fully blunting the increases in the mRNA for of atrogin-1, MURF-1, and myostatin, e.g., sensitive gene markers of an activated catabolic state. Analyses of the IRS-1/PI3K/Akt markers indicated that abundance of IRS-1 and phosphorylation state of Akt and p70S6 kinase were decreased relative to normal control rats, and the resistance training failed to maintain these signaling markers at normal regulatory level. Our findings suggest that to fully prevent muscle atrophy responses affecting the myofibril system during unloading, the volume of mechanical stress must be augmented sufficiently to maintain optimal activity of the IRS-1/PI3K/Akt pathway to provide an effective anabolic stimulus on the muscle. PMID:16239603

  10. Impaired Axonal Na(+) Current by Hindlimb Unloading: Implication for Disuse Neuromuscular Atrophy.

    PubMed

    Banzrai, Chimeglkham; Nodera, Hiroyuki; Kawarai, Toshitaka; Higashi, Saki; Okada, Ryo; Mori, Atsuko; Shimatani, Yoshimitsu; Osaki, Yusuke; Kaji, Ryuji

    2016-01-01

    This study aimed to characterize the excitability changes in peripheral motor axons caused by hindlimb unloading (HLU), which is a model of disuse neuromuscular atrophy. HLU was performed in normal 8-week-old male mice by fixing the proximal tail by a clip connected to the top of the animal's cage for 3 weeks. Axonal excitability studies were performed by stimulating the sciatic nerve at the ankle and recording the compound muscle action potential (CMAP) from the foot. The amplitudes of the motor responses of the unloading group were 51% of the control amplitudes [2.2 ± 1.3 mV (HLU) vs. 4.3 ± 1.2 mV (Control), P = 0.03]. Multiple axonal excitability analysis showed that the unloading group had a smaller strength-duration time constant (SDTC) and late subexcitability (recovery cycle) than the controls [0.075 ± 0.01 (HLU) vs. 0.12 ± 0.01 (Control), P < 0.01; 5.4 ± 1.0 (HLU) vs. 10.0 ± 1.3 % (Control), P = 0.01, respectively]. Three weeks after releasing from HLU, the SDTC became comparable to the control range. Using a modeling study, the observed differences in the waveforms could be explained by reduced persistent Na(+) currents along with parameters related to current leakage. Quantification of RNA of a SCA1A gene coding a voltage-gated Na(+) channel tended to be decreased in the sciatic nerve in HLU. The present study suggested that axonal ion currents are altered in vivo by HLU. It is still undetermined whether the dysfunctional axonal ion currents have any pathogenicity on neuromuscular atrophy or are the results of neural plasticity by atrophy. PMID:26909041

  11. Shock compression and unloading response of 1050 aluminum to 70 GPA

    NASA Astrophysics Data System (ADS)

    Choudhuri, Deep; Gupta, Yogendra M.

    2012-03-01

    Using laser-interferometry, shock compression and unloading profiles were measured in 1050 aluminum shocked to ~70 GPa. These results were compared to published data on relatively pure (99.99wt% ultra pure, 1050, 1060, and 1100) and precipitate - hardened (2024, 6061) aluminum. Within experimental scatter, Hugoniots and longitudinal sound speeds (in the shocked state) of pure and precipitate-hardened aluminum are quite comparable to 70GPa. This agreement demonstrates that impurity content has minimal influence on the longitudinal stress-volume response and acoustic speeds under shock compression.

  12. The molecular response of bone to growth hormone during skeletal unloading: regional differences

    NASA Technical Reports Server (NTRS)

    Bikle, D. D.; Harris, J.; Halloran, B. P.; Currier, P. A.; Tanner, S.; Morey-Holton, E.

    1995-01-01

    Hind limb elevation of the growing rat provides a good model for the skeletal changes that occur during space flight. In this model the bones of the forelimbs (normally loaded) are used as an internal control for the changes that occur in the unloaded bones of the hind limbs. Previous studies have shown that skeletal unloading of the hind limbs results in a transient reduction of bone formation in the tibia and femur, with no change in the humerus. This fall in bone formation is accompanied by a fall in serum osteocalcin (bone Gla protein, BGP) and bone BGP messenger RNA (mRNA) levels, but a rise in bone insulin-like growth factor-I (IGF-I) protein and mRNA levels and resistance to the skeletal growth-promoting actions of IGF-I. To determine whether skeletal unloading also induced resistance to GH, we evaluated the response of the femur and humerus of sham and hypophysectomized rats, control and hind limb elevated, to GH (two doses), measuring mRNA levels of IGF-I, BGP, rat bone alkaline phosphatase (RAP), and alpha 1(1)-procollagen (coll). Hypophysectomy (HPX) decreased the mRNA levels of IGF-I, BGP, and coll in the femur, but was either less effective or had the opposite effect in the humerus. GH at the higher dose (500 micrograms/day) restored these mRNA levels to or above the sham control values in the femur, but generally had little or no effect on the humerus. RAP mRNA levels were increased by HPX, especially in the femur. The lower dose of GH (50 micrograms/day) inhibited this rise in RAP, whereas the higher dose raised the mRNA levels and resulted in the appearance of additional transcripts not seen in controls. As for the other mRNAs, RAP mRNA in the humerus was less affected by HPX or GH than that in the femur. Hind limb elevation led to an increase in IGF-I, coll, and RAP mRNAs and a reduction in BGP mRNA in the femur and either had no effect or potentiated the response of these mRNAs to GH. We conclude that GH stimulates a number of markers of bone

  13. High Salt Diets, Bone Strength and Mineral Content of Mature Femur After Skeletal Unloading

    NASA Technical Reports Server (NTRS)

    Liang, Michael T. C.

    1998-01-01

    It is known that high salt diets increase urinary calcium (Ca) loss, but it is not known whether this effect weakens bone during space flight. The Bone Hormone Lab has studied the effect of high salt diets on Ca balance and whole body Ca in a space flight model (2,8). Neither the strength nor mineral content of the femurs from these studies has been evaluated. The purpose of this study was to determine the effect of high salt diets (HiNa) and skeletal unloading on femoral bone strength and bone mineral content (BMC) in mature rats.

  14. Interdependence of Muscle Atrophy and Bone Loss Induced by Mechanical Unloading

    PubMed Central

    Lloyd, Shane A.; Lang, Charles H.; Zhang, Yue; Paul, Emmanuel M.; Laufenberg, Lacee J.; Lewis, Gregory S.; Donahue, Henry J.

    2014-01-01

    Mechanical unloading induces muscle atrophy and bone loss; however, the time course and interdependence of these effects is not well defined. We subjected 4-month-old C57BL/6J mice to hindlimb suspension (HLS) for three weeks, sacrificing 12-16 mice on day (D) 0, 7, 14, and 21. Lean mass was 7-9% lower for HLS vs. control from D7-21. Absolute mass of the gastrocnemius (gastroc) decreased 8% by D7, and was maximally decreased 16% by D14 of HLS. mRNA levels of Atrogin-1 in the gastroc and quad were increased 99% and 122%, respectively, at D7 of HLS. Similar increases in MuRF1 mRNA levels occurred at D7. Both atrogenes returned to baseline by D14. Protein synthesis in gastroc and quad was reduced 30% from D7-14 of HLS, returning to baseline by D21. HLS decreased phosphorylation of SK61, a substrate of mammalian target of rapamycin (mTOR), on D7-21, while 4E-BP1 was not lower until D21. Cortical thickness of the femur and tibia did not decrease until D14 of HLS. Cortical bone of controls did not change over time. HLS mice had lower distal femur bone volume fraction (−22%) by D14; however, the effects of HLS were eliminated by D21 due to the decline of trabecular bone mass of controls. Femur strength was decreased approximately 13% by D14 of HLS, with no change in tibia mechanical properties at any time point. This investigation reveals that muscle atrophy precedes bone loss during unloading and may contribute to subsequent skeletal deficits. Countermeasures that preserve muscle may reduce bone loss induced by mechanical unloading or prolonged disuse. Trabecular bone loss with age, similar to that which occurs in mature astronauts, is superimposed on unloading. Preservation of muscle mass, cortical structure, and bone strength during the experiment suggests muscle may have a greater effect on cortical than trabecular bone. PMID:24127218

  15. Systemic administration of IGF-I enhances healing in collagenous extracellular matrices: evaluation of loaded and unloaded ligaments

    PubMed Central

    Provenzano, Paolo P; Alejandro-Osorio, Adriana L; Grorud, Kelley W; Martinez, Daniel A; Vailas, Arthur C; Grindeland, Richard E; Vanderby, Ray

    2007-01-01

    Background Insulin-like growth factor-I (IGF-I) plays a crucial role in wound healing and tissue repair. We tested the hypotheses that systemic administration of IGF-I, or growth hormone (GH), or both (GH+IGF-I) would improve healing in collagenous connective tissue, such as ligament. These hypotheses were examined in rats that were allowed unrestricted activity after injury and in animals that were subjected to hindlimb disuse. Male rats were assigned to three groups: ambulatory sham-control, ambulatory-healing, and hindlimb unloaded-healing. Ambulatory and hindlimb unloaded animals underwent surgical disruption of their knee medial collateral ligaments (MCLs), while sham surgeries were performed on control animals. Healing animals subcutaneously received systemic doses of either saline, GH, IGF-I, or GH+IGF-I. After 3 weeks, mechanical properties, cell and matrix morphology, and biochemical composition were examined in control and healing ligaments. Results Tissues from ambulatory animals receiving only saline had significantly greater strength than tissue from saline receiving hindlimb unloaded animals. Addition of IGF-I significantly improved maximum force and ultimate stress in tissues from both ambulatory and hindlimb unloaded animals with significant increases in matrix organization and type-I collagen expression. Addition of GH alone did not have a significant effect on either group, while addition of GH+IGF-I significantly improved force, stress, and modulus values in MCLs from hindlimb unloaded animals. Force, stress, and modulus values in tissues from hindlimb unloaded animals receiving IGF-I or GH+IGF-I exceeded (or were equivalent to) values in tissues from ambulatory animals receiving only saline with greatly improved structural organization and significantly increased type-I collagen expression. Furthermore, levels of IGF-receptor were significantly increased in tissues from hindlimb unloaded animals treated with IGF-I. Conclusion These results

  16. Phloem unloading follows an extensive apoplasmic pathway in cucumber (Cucumis sativus L.) fruit from anthesis to marketable maturing stage.

    PubMed

    Hu, Liping; Sun, Huihui; Li, Ruifu; Zhang, Lingyun; Wang, Shaohui; Sui, Xiaolei; Zhang, Zhenxian

    2011-11-01

    The phloem unloading pathway remains unclear in fruits of Cucurbitaceae, a classical stachyose-transporting species with bicollateral phloem. Using a combination of electron microscopy, transport of phloem-mobile symplasmic tracer carboxyfluorescein, assays of acid invertase and sucrose transporter, and [(14)C]sugar uptake, the phloem unloading pathway was studied in cucumber (Cucumis sativus) fruit from anthesis to the marketable maturing stage. Structural investigations showed that the sieve element-companion cell (SE-CC) complex of the vascular bundles feeding fruit flesh is apparently symplasmically restricted. Imaging of carboxyfluorescein unloading showed that the dye remained confined to the phloem strands of the vascular bundles in the whole fruit throughout the stages examined. A 37 kDa acid invertase was located predominantly in the cell walls of SE-CC complexes and parenchyma cells. Studies of [(14)C]sugar uptake suggested that energy-driven transporters may be functional in sugar trans-membrane transport within symplasmically restricted SE-CC complex, which was further confirmed by the existence of a functional plasma membrane sucrose transporter (CsSUT4) in cucumber fruit. These data provide a clear evidence for an apoplasmic phloem unloading pathway in cucumber fruit. A presumption that putative raffinose or stachyose transporters may be involved in soluble sugars unloading was discussed. PMID:21707653

  17. Replication-Coupled PCNA Unloading by the Elg1 Complex Occurs Genome-wide and Requires Okazaki Fragment Ligation

    PubMed Central

    Kubota, Takashi; Katou, Yuki; Nakato, Ryuichiro; Shirahige, Katsuhiko; Donaldson, Anne D.

    2015-01-01

    Summary The sliding clamp PCNA is a crucial component of the DNA replication machinery. Timely PCNA loading and unloading are central for genome integrity and must be strictly coordinated with other DNA processing steps during replication. Here, we show that the S. cerevisiae Elg1 replication factor C-like complex (Elg1-RLC) unloads PCNA genome-wide following Okazaki fragment ligation. In the absence of Elg1, PCNA is retained on chromosomes in the wake of replication forks, rather than at specific sites. Degradation of the Okazaki fragment ligase Cdc9 leads to PCNA accumulation on chromatin, similar to the accumulation caused by lack of Elg1. We demonstrate that Okazaki fragment ligation is the critical prerequisite for PCNA unloading, since Chlorella virus DNA ligase can substitute for Cdc9 in yeast and simultaneously promotes PCNA unloading. Our results suggest that Elg1-RLC acts as a general PCNA unloader and is dependent upon DNA ligation during chromosome replication. PMID:26212319

  18. Icaritin requires Phosphatidylinositol 3 kinase (PI3K)/Akt signaling to counteract skeletal muscle atrophy following mechanical unloading

    PubMed Central

    ZHANG, Zong-Kang; LI, Jie; LIU, Jin; GUO, Baosheng; LEUNG, Albert; ZHANG, Ge; ZHANG, Bao-Ting

    2016-01-01

    Counteracting muscle atrophy induced by mechanical unloading/inactivity is of great clinical need and challenge. A therapeutic agent that could counteract muscle atrophy following mechanical unloading in safety is desired. This study showed that natural product Icaritin (ICT) could increase the phosphorylation level of Phosphatidylinositol 3 kinase (PI3K) at p110 catalytic subunit and promote PI3K/Akt signaling markers in C2C12 cells. This study further showed that the high dose ICT treatment could significantly attenuate the decreases in the phosphorylation level of PI3K at p110 catalytic subunit and its downstream markers related to protein synthesis, and inhibit the increases in protein degradation markers at mRNA and protein levels in rat soleus muscle following 28-day hindlimb unloading. In addition, the decreases in soleus muscle mass, muscle fiber cross-sectional area, twitch force, specific force, contraction time and half relaxation time could be significantly attenuated by the high dose ICT treatment. The low dose ICT treatment could moderately attenuate the above changes induced by unloading. Wortmannin, a specific inhibitor of PI3K at p110 catalytic subunit, could abolish the above effects of ICT in vitro and in vivo, indicating that PI3K/Akt signaling could be required by ICT to counteract skeletal muscle atrophy following mechanical unloading. PMID:26831566

  19. Multi-step loading/unloading experiments that challenge constitutive models of glassy polymers

    NASA Astrophysics Data System (ADS)

    Caruthers, James; Medvedev, Grigori

    2014-03-01

    The mechanical response of glassy polymers depends on the thermal and deformational history, where the resulting relaxation phenomenon remains a significant challenge for constitutive modeling. For strain controlled experiments the stress response is measured during loading/unloading ramps and a constant strain. By judiciously combining the basic steps, a set of multi-step experiments have been designed to challenge existing constitutive models for glassy polymers. A particular example is the ``stress memory'' experiment, i.e. loading through yield, unloading to zero stress, and holding at final strain, where the subsequent evolution of the stress exhibits an overshoot. The observed dependence of the overshoot on the loading strain rate cannot be explained by the models where the relaxation time is a function of stress or strain. Another discriminating multi-step history experiment involves strain accumulation to test the common assumption that the phenomenon of strain hardening is caused by a purely elastic contribution to stress. Experimental results will be presented for a low Tg epoxy system, and the data will be used to critically analyze the predictions of both traditional viscoelastic/viscoplastic constitutive models and a recently developed Stochastic Constitutive Model.

  20. An unload-induced direct-shear model for granular gouge friction in rock discontinuities.

    PubMed

    Wu, Wei; Zou, Yang; Li, Xing; Zhao, Jian

    2014-09-01

    The experimental study introduces an unload-induced direct-shear model to investigate the frictional slip of a layer of simulated granular gouges induced by the combination of a decreasing normal stress and a constant shear stress. A frictional equilibrium state of the gouge layer is initially established under fixed normal and shear stresses. The normal stress is proposed to decrease at a constant unloading rate to induce the frictional slip of the gouge layer, and the shear stress is proposed to keep a constant value during the test. A displacement meter and load cells synchronously measure the slip displacement and the applied normal and shear stresses, respectively. The normal and shear stresses sharply decrease with the frictional slip, owing to damage of gouge contacts. The frictional slip is then gradually arrested with new formation of gouge contacts. A greater initial shear stress induces larger normal and shear stress reductions and a smaller slip displacement. The strain energy stored in the discontinuous system before the frictional slip is found to affect the slip displacement. The advantages and the limitations of this model are discussed at the end. PMID:25273734

  1. Early changes in costameric and mitochondrial protein expression with unloading are muscle specific.

    PubMed

    Flück, Martin; Li, Ruowei; Valdivieso, Paola; Linnehan, Richard M; Castells, Josiane; Tesch, Per; Gustafsson, Thomas

    2014-01-01

    We hypothesised that load-sensitive expression of costameric proteins, which hold the sarcomere in place and position the mitochondria, contributes to the early adaptations of antigravity muscle to unloading and would depend on muscle fibre composition and chymotrypsin activity of the proteasome. Biopsies were obtained from vastus lateralis (VL) and soleus (SOL) muscles of eight men before and after 3 days of unilateral lower limb suspension (ULLS) and subjected to fibre typing and measures for costameric (FAK and FRNK), mitochondrial (NDUFA9, SDHA, UQCRC1, UCP3, and ATP5A1), and MHCI protein and RNA content. Mean cross-sectional area (MCSA) of types I and II muscle fibres in VL and type I fibres in SOL demonstrated a trend for a reduction after ULLS (0.05 ≤ P < 0.10). FAK phosphorylation at tyrosine 397 showed a 20% reduction in VL muscle (P = 0.029). SOL muscle demonstrated a specific reduction in UCP3 content (-23%; P = 0.012). Muscle-specific effects of ULLS were identified for linear relationships between measured proteins, chymotrypsin activity and fibre MCSA. The molecular modifications in costamere turnover and energy homoeostasis identify that aspects of atrophy and fibre transformation are detectable at the protein level in weight-bearing muscles within 3 days of unloading. PMID:25313365

  2. Skeletal unloading and dietary copper depletion are detrimental to bone quality of mature rats

    NASA Technical Reports Server (NTRS)

    Smith, Brenda J.; King, Jarrod B.; Lucas, Edralin A.; Akhter, Mohammed P.; Arjmandi, Bahram H.; Stoecker, Barbara J.

    2002-01-01

    This study was designed to examine the skeletal response to copper depletion and mechanical unloading in mature animals. In a 2 x 2 experimental design, 5.5-mo-old male Sprague-Dawley rats (n = 36) consumed either the control (AIN-93M) or Cu-depletion ((-)Cu) diet beginning 21 d before suspension and throughout the remainder of the study. Half of the rats in each dietary treatment group were either tail-suspended (TS) or kept ambulatory (AMB) for 28 d. Lower bone mineral densities (BMD) of 5th lumbar vertebra (L5) (P < 0.05) and femur were observed with (-)Cu and TS, but no differences were noted in the BMD of the humerus. Mechanical strength in the femur and vertebra decreased in response to TS, but were unaffected by copper depletion. Urinary deoxypyridinoline, an index of bone resorption, was significantly greater in TS rats, but unaltered by (-)Cu. No changes in serum or bone alkaline phosphatase activity, an indicator of bone formation, were observed. Our findings suggest that TS and (-)Cu decreased BMD in unloaded femur and vertebra but had no effect on normally loaded humerus. Bone loss with TS appeared to be related to accelerated bone resorption. Alterations in bone metabolism and bone mechanical properties in the mature skeleton resulting from (-)Cu warrant further investigation.

  3. Bone and hormonal changes induced by skeletal unloading in the mature male rat

    NASA Technical Reports Server (NTRS)

    Dehority, W.; Halloran, B. P.; Bikle, D. D.; Curren, T.; Kostenuik, P. J.; Wronski, T. J.; Shen, Y.; Rabkin, B.; Bouraoui, A.; Morey-Holton, E.

    1999-01-01

    To determine whether the rat hindlimb elevation model can be used to study the effects of spaceflight and loss of gravitational loading on bone in the adult animal, and to examine the effects of age on bone responsiveness to mechanical loading, we studied 6-mo-old rats subjected to hindlimb elevation for up to 5 wk. Loss of weight bearing in the adult induced a mild hypercalcemia, diminished serum 1,25-dihydroxyvitamin D, decreased vertebral bone mass, and blunted the otherwise normal increase in femoral mass associated with bone maturation. Unloading decreased osteoblast numbers and reduced periosteal and cancellous bone formation but had no effect on bone resorption. Mineralizing surface, mineral apposition rate, and bone formation rate decreased during unloading. Our results demonstrate the utility of the adult rat hindlimb elevation model as a means of simulating the loss of gravitational loading on the skeleton, and they show that the effects of nonweight bearing are prolonged and have a greater relative effect on bone formation in the adult than in the young growing animal.

  4. A Hypomagnetic Field Aggravates Bone Loss Induced by Hindlimb Unloading in Rat Femurs

    PubMed Central

    Jia, Bin; Xie, Li; Zheng, Qi; Yang, Peng-fei; Zhang, Wei-ju; Ding, Chong; Qian, Ai-rong; Shang, Peng

    2014-01-01

    A hypomagnetic field is an extremely weak magnetic field—it is considerably weaker than the geomagnetic field. In deep-space exploration missions, such as those involving extended stays on the moon and interplanetary travel, astronauts will experience abnormal space environments involving hypomagnetic fields and microgravity. It is known that microgravity in space causes bone loss, which results in decreased bone mineral density. However, it is unclear whether hypomagnetic fields affect the skeletal system. In the present study, we aimed to investigate the complex effects of a hypomagnetic field and microgravity on bone loss. To study the effects of hypomagnetic fields on the femoral characteristics of rats in simulated weightlessness, we established a rat model of hindlimb unloading that was exposed to a hypomagnetic field. We used a geomagnetic field-shielding chamber to generate a hypomagnetic field of <300 nT. The results show that hypomagnetic fields can exacerbate bone mineral density loss and alter femoral biomechanical characteristics in hindlimb-unloaded rats. The underlying mechanism might involve changes in biological rhythms and the concentrations of trace elements due to the hypomagnetic field, which would result in the generation of oxidative stress responses in the rat. Excessive levels of reactive oxygen species would stimulate osteoblasts to secrete receptor activator of nuclear factor-κB ligand and promote the maturation and activation of osteoclasts and thus eventually cause bone resorption. PMID:25157571

  5. Fractal dimension analysis of weight-bearing bones of rats during skeletal unloading

    NASA Technical Reports Server (NTRS)

    Pornprasertsuk, S.; Ludlow, J. B.; Webber, R. L.; Tyndall, D. A.; Sanhueza, A. I.; Yamauchi, M.

    2001-01-01

    Fractal analysis was used to quantify changes in trabecular bone induced through the use of a rat tail-suspension model to simulate microgravity-induced osteopenia. Fractal dimensions were estimated from digitized radiographs obtained from tail-suspended and ambulatory rats. Fifty 4-month-old male Sprague-Dawley rats were divided into groups of 24 ambulatory (control) and 26 suspended (test) animals. Rats of both groups were killed after periods of 1, 4, and 8 weeks. Femurs and tibiae were removed and radiographed with standard intraoral films and digitized using a flatbed scanner. Square regions of interest were cropped at proximal, middle, and distal areas of each bone. Fractal dimensions were estimated from slopes of regression lines fitted to circularly averaged plots of log power vs. log spatial frequency. The results showed that the computed fractal dimensions were significantly greater for images of trabecular bones from tail-suspended groups than for ambulatory groups (p < 0.01) at 1 week. Periods between 1 and 4 weeks likewise yielded significantly different estimates (p < 0.05), consistent with an increase in bone loss. In the tibiae, the proximal regions of the suspended group produced significantly greater fractal dimensions than other regions (p < 0.05), which suggests they were more susceptible to unloading. The data are consistent with other studies demonstrating osteopenia in microgravity environments and the regional response to skeletal unloading. Thus, fractal analysis could be a useful technique to evaluate the structural changes of bone.

  6. Hind limb unloading, a model of spaceflight conditions, leads to decreased B lymphopoiesis similar to aging.

    PubMed

    Lescale, Chloé; Schenten, Véronique; Djeghloul, Dounia; Bennabi, Meriem; Gaignier, Fanny; Vandamme, Katleen; Strazielle, Catherine; Kuzniak, Isabelle; Petite, Hervé; Dosquet, Christine; Frippiat, Jean-Pol; Goodhardt, Michele

    2015-02-01

    Within the bone marrow, the endosteal niche plays a crucial role in B-cell differentiation. Because spaceflight is associated with osteoporosis, we investigated whether changes in bone microstructure induced by a ground-based model of spaceflight, hind limb unloading (HU), could affect B lymphopoiesis. To this end, we analyzed both bone parameters and the frequency of early hematopoietic precursors and cells of the B lineage after 3, 6, 13, and 21 d of HU. We found that limb disuse leads to a decrease in both bone microstructure and the frequency of B-cell progenitors in the bone marrow. Although multipotent hematopoietic progenitors were not affected by HU, a decrease in B lymphopoiesis was observed as of the common lymphoid progenitor (CLP) stage with a major block at the progenitor B (pro-B) to precursor B (pre-B) cell transition (5- to 10-fold decrease). The modifications in B lymphopoiesis were similar to those observed in aged mice and, as with aging, decreased B-cell generation in HU mice was associated with reduced expression of B-cell transcription factors, early B-cell factor (EBF) and Pax5, and an alteration in STAT5-mediated IL-7 signaling. These findings demonstrate that mechanical unloading of hind limbs results in a decrease in early B-cell differentiation resembling age-related modifications in B lymphopoiesis. PMID:25376832

  7. Hindlimb unloading has a greater effect on cortical compared with cancellous bone in mature female rats

    NASA Technical Reports Server (NTRS)

    Allen, Matthew R.; Bloomfield, Susan A.

    2003-01-01

    This study was designed to determine the effects of 28 days of hindlimb unloading (HU) on the mature female rat skeleton. In vivo proximal tibia bone mineral density and geometry of HU and cage control (CC) rats were measured with peripheral quantitative computed tomography (pQCT) on days 0 and 28. Postmortem pQCT, histomorphometry, and mechanical testing were performed on tibiae and femora. After 28 days, HU animals had significantly higher daily food consumption (+39%) and lower serum estradiol levels (-49%, P = 0.079) compared with CC. Proximal tibia bone mineral content and cortical bone area significantly declined over 28 days in HU animals (-4.0 and 4.8%, respectively), whereas total and cancellous bone mineral densities were unchanged. HU animals had lower cortical bone formation rates and mineralizing surface at tibial midshaft, whereas differences in similar properties were not detected in cancellous bone of the distal femur. These results suggest that cortical bone, rather than cancellous bone, is more prominently affected by unloading in skeletally mature retired breeder female rats.

  8. Hindlimb unloading induces a collagen isoform shift in the soleus muscle of the rat

    NASA Technical Reports Server (NTRS)

    Miller, T. A.; Lesniewski, L. A.; Muller-Delp, J. M.; Majors, A. K.; Scalise, D.; Delp, M. D.

    2001-01-01

    To determine whether hindlimb unloading (HU) alters the extracellular matrix of skeletal muscle, male Sprague-Dawley rats were subjected to 0 (n = 11), 1 (n = 11), 14 (n = 13), or 28 (n = 11) days of unloading. Remodeling of the soleus and plantaris muscles was examined biochemically for collagen abundance via measurement of hydroxyproline, and the percentage of cross-sectional area of collagen was determined histologically with picrosirius red staining. Total hydroxyproline content in the soleus and plantaris muscles was unaltered by HU at any time point. However, the relative proportions of type I collagen in the soleus muscle decreased relative to control (Con) with 14 and 28 days HU (Con 68 +/- 5%; 14 days HU 53 +/- 4%; 28 days HU 53 +/- 7%). Correspondingly, type III collagen increased in soleus muscle with 14 and 28 days HU (Con 32 +/- 5%; 14 days HU 47 +/- 4%; 28 days HU 48 +/- 7%). The proportion of type I muscle fibers in soleus muscle was diminished with HU (Con 96 +/- 2%; 14 days HU 86 +/- 1%; 28 days HU 83 +/- 1%), and the proportion of hybrid type I/IIB fibers increased (Con 0%; 14 days HU 8 +/- 2%; 28 days HU 14 +/- 2%). HU had no effect on the proportion of type I and III collagen or muscle fiber composition in plantaris muscle. The data demonstrate that HU induces a shift in the relative proportion of collagen isoform (type I to III) in the antigravity soleus muscle, which occurs concomitantly with a slow-to-fast myofiber transformation.

  9. The Hindlimb Unloading Rat Model: Literature Overview, Comparison with Spaceflight Data, and Technique Update

    NASA Technical Reports Server (NTRS)

    Morey-Holton, Emily; Globus, Ruth K.; Kaplansky, Alexander; Durnova, Galina

    2004-01-01

    The hindlimb unloading (HU) rodent model is used extensively to study the response of many physiological systems to certain aspects of spaceflight, as well as to disuse and recovery from disuse for Earth benefits. This chapter describes the evolution of HU, and is divided into three sections. The first section examines the characteristics of 1063 articles using or reviewing the HU model, published between 1976 and April 1, 2004. The characteristics include number of publications, journals, countries, major physiological systems, method modifications, species, gender, genetic strains and ages of rodents, experiment duration, and countermeasures. The second section provides a comparison of results between space flown and Hu animals from the 14-day Cosmos 2044 mission. The final section describes modifications to HU required by different experimental paradigms and a method to protect the tail harness for long duration studies. HU in rodents has enabled improved understanding of the responses of the musculoskeletal, cardiovascular, immune, renal, neural, metabolic, and reproductive systems to unloading and/or to reloading on Earth with implications for both long-duration human spaceflight and disuse on Earth.

  10. Can footwall unloading explain late Cenozoic uplift of the Sierra Nevada crest?

    USGS Publications Warehouse

    Thompson, G.A.; Parsons, T.

    2009-01-01

    Globally, normal-fault displacement bends and warps rift flanks upwards, as adjoining basins drop downwards. Perhaps the most evident manifestations are the flanks of the East African Rift, which cuts across the otherwise minimally deformed continent. Flank uplift was explained by Vening Meinesz (1950, Institut Royal Colonial Belge, Bulletin des Seances, v. 21, p. 539-552), who recognized that isostasy should cause uplift of a normal-faulted footwall and subsidence of its hanging wall. Uplift occurs because slip on a dipping normal fault creates a broader root of less-dense material beneath the footwall, and a narrowed one beneath the hanging wall. In this paper, we investigate the potential influence of this process on the latest stages of Sierra Nevada uplift. Through theoretical calculations and 3D finite element modelling, we find that cumulative slip of about 4km on range-front faults would have produced about 1.3km peak isostatic uplift at the ridge crest. Numerical models suggest that the zone of uplift is narrow, with the width controlled by bending resistance of the seismogenic crust. We conclude that footwall unloading cannot account for the entire elevation of the Sierran crest above sea level, but if range-front faulting initiated in an already elevated plateau like the adjacent Basin and Range Province, then a hybrid model of pre-existing regional uplift and localized footwall unloading can account for the older and newer uplift phases suggested by the geologic record.

  11. Effects of space flight conditions on the function of the immune system and catecholamine production simulated in a rodent model of hindlimb unloading

    NASA Technical Reports Server (NTRS)

    Aviles, Hernan; Belay, Tesfaye; Vance, Monique; Sonnenfeld, Gerald

    2005-01-01

    The rodent model of hindlimb unloading has been successfully used to simulate some of the effects of space flight conditions. Previous studies have indicated that mice exposed to hindlimb-unloading conditions have decreased resistance to infections compared to restrained and normally housed control mice. OBJECTIVE: The purpose of this study was to clarify the mechanisms involved in resistance to infection in this model by examining the effects of hindlimb unloading on the function of the immune system and its impact on the production of catecholamines. METHODS: Female Swiss Webster mice were hindlimb-unloaded during 48 h and the function of the immune system was assessed in spleen and peritoneal cells immediately after this period. In addition, the kinetics of catecholamine production was measured throughout the hindlimb-unloading period. RESULTS: The function of the immune system was significantly suppressed in the hindlimb-unloaded group compared to restrained and normally housed control mice. Levels of catecholamines were increased in the hindlimb-unloaded group and peaked at 12 h following the commencement of unloading. CONCLUSION: These results suggest that physiological responses of mice are altered early after hindlimb unloading and that catecholamines may play a critical role in the modulation of the immune system. These changes may affect the ability of mice to resist infections. Copyright (c) 2005 S. Karger AG, Basel.

  12. Effect of a magnetic field on crack length measurement of 9NI steel by unloading compliance method

    NASA Astrophysics Data System (ADS)

    Nagasaki, C.; Matsui, K.; Shibata, K.

    2002-05-01

    In the fracture toughness measurement of ferro-magnetic materials in high magnetic fields, it has not been clarified whether we can use the same formulas as ones used in a non-magnetic field. Therefore, it is necessary to understand the magnetic effect in the fracture toughness measurement of ferro-magnetic materials. As the first step, crack length was measured at 4 K by unloading compliance method in the testing of CT specimen of 9% nickel steel. The same formula was used in the magnetic field of 0 and 8 Tesla. They were compared with the length measured by optical fractography. The magnetic field had little effect on the crack length measurement by the unloading compliance method. The small amount of retained austenite in Q T heat-treated specimen did not exhibit a magnetic effect on the crack length measurement by the unloading compliance method.

  13. Muscle progenitor cells proliferation doesn't sufficiently contribute to maintaining stretched soleus muscle mass during gravitational unloading

    NASA Astrophysics Data System (ADS)

    Tarakina, M. V.; Turtikova, O. V.; Nemirovskaya, T. L.; Kokontcev, A. A.; Shenkman, B. S.

    Skeletal muscle work hypertrophy is usually connected with muscle progenitor satellite cells (SC) activation with subsequent incorporation of their nuclei into myofibers. Passive stretch of unloaded muscle was earlier established to prevent atrophic processes and is accompanied by enhanced protein synthesis. We hypothesized that elimination of SC proliferation capacity by γ-irradiation would partly avert stretched muscle fiber capability to maintain their size under the conditions of gravitational unloading. To assess the role of muscle progenitor (satellite) cells in development of passive stretch preventive effect SC proliferation was suppressed by local exposing to ionized radiation (2500 rad), subsequent hindlimb suspension or hindlimb suspension with concomitant passive stretch were carried out. Reduction of myofiber cross-sectional area and decrease in myonuclei number accompanying unloaded muscle atrophy were completely abolished by passive stretch both in irradiated and sham-treated animals. We conclude that SC did not make essential contribution to passive stretch preventive action under the conditions of simulated weightlessness.

  14. Skeletal unloading causes resistance of osteoprogenitor cells to parathyroid hormone and to insulin-like growth factor-I

    NASA Technical Reports Server (NTRS)

    Kostenuik, P. J.; Harris, J.; Halloran, B. P.; Turner, R. T.; Morey-Holton, E. R.; Bikle, D. D.

    1999-01-01

    Skeletal unloading decreases bone formation and osteoblast number in vivo and decreases the number and proliferation of bone marrow osteoprogenitor (BMOp) cells in vitro. We tested the ability of parathyroid hormone (PTH) to stimulate BMOp cells in vivo by treating Sprague Dawley rats (n = 32) with intermittent PTH(1-34) (1 h/day at 8 microg/100 g of body weight), or with vehicle via osmotic minipumps during 7 days of normal weight bearing or hind limb unloading. Marrow cells were flushed from the femur and cultured at the same initial density for up to 21 days. PTH treatment of normally loaded rats caused a 2.5-fold increase in the number of BMOp cells, with similar increases in alkaline phosphatase (ALP) activity and mineralization, compared with cultures from vehicle-treated rats. PTH treatment of hind limb unloaded rats failed to stimulate BMOp cell number, ALP activity, or mineralization. Hind limb unloading had no significant effect on PTH receptor mRNA or protein levels in the tibia. Direct in vitro PTH challenge of BMOp cells isolated from normally loaded bone failed to stimulate their proliferation and inhibited their differentiation, suggesting that the in vivo anabolic effect of intermittent PTH on BMOp cells was mediated indirectly by a PTH-induced factor. We hypothesize that this factor is insulin-like growth factor-I (IGF-I), which stimulated the in vitro proliferation and differentiation of BMOp cells isolated from normally loaded bone, but not from unloaded bone. These results suggest that IGF-I mediates the ability of PTH to stimulate BMOp cell proliferation in normally loaded bone, and that BMOp cells in unloaded bone are resistant to the anabolic effect of intermittent PTH therapy due to their resistance to IGF-I.

  15. Effect of short-term microgravity and long-term hindlimb unloading on rat cardiac mass and function

    NASA Technical Reports Server (NTRS)

    Ray, C. A.; Vasques, M.; Miller, T. A.; Wilkerson, M. K.; Delp, M. D.

    2001-01-01

    The purpose of this study was to test the hypothesis that exposure to short-term microgravity or long-term hindlimb unloading induces cardiac atrophy in male Sprague-Dawley rats. For the microgravity study, rats were subdivided into four groups: preflight (PF, n = 12); flight (Fl, n = 7); flight cage simulation (Sim, n = 6), and vivarium control (Viv, n = 7). Animals in the Fl group were exposed to 7 days of microgravity during the Spacelab 3 mission. Animals in the hindlimb-unloading study were subdivided into three groups: control (Con, n = 20), 7-day hindlimb-unloaded (7HU, n = 10), and 28-day hindlimb-unloaded (28HU, n = 19). Heart mass was unchanged in adult animals exposed to 7 days of actual microgravity (PF 1.33 +/- 0.03 g; Fl 1.32 +/- 0.02 g; Sim 1.28 +/- 0.04 g; Viv 1.35 +/- 0.04 g). Similarly, heart mass was unaltered with hindlimb unloading (Con 1.40 +/- 0.04 g; 7HU 1.35 +/- 0.06 g; 28HU 1.42 +/- 0.03 g). Hindlimb unloading also had no effect on the peak rate of rise in left ventricular pressure, an estimate of myocardial contractility (Con 8,055 +/- 385 mmHg/s; 28HU 8,545 +/- 755 mmHg/s). These data suggest that cardiac atrophy does not occur after short-term exposure to microgravity and that neither short- nor long-term simulated microgravity alters cardiac mass or function.

  16. Beta-Catenin Haplo Insufficient Male Mice Do Not Lose Bone in Response to Hindlimb Unloading

    PubMed Central

    Farr, Joshua; Cheng, An-Lin; Johnson, Mark L.; Bonewald, Lynda F.

    2016-01-01

    As the β-catenin pathway has been shown to be involved in mechanotransduction, we sought to determine if haploinsufficiency would affect skeletal response to unloading. It has previously been shown that deletion of both alleles of β-catenin in bone cells results in a fragile skeleton highly susceptible to fracture, but deletion of one allele using Dmp1-Cre (Ctnnb1+/loxP; Dmp1-Cre, cKO HET) has little effect on the 2 mo old skeleton. We found that under normal housing conditions, trabecular bone volume was significantly less in 5 mo old male cKO HET mice compared to controls (Ctrl/HET:Tb. BV/TV = 13.96±2.71/8.92±0.95%, Tb.N. = 4.88±0.51/3.95±0.44/mm, Tb. Sp. = 0.20±0.02/0.26±0.03mm, a 36%, 19% and 30% change respectively) but not in females suggesting an age and gender related effect. Before performing suspension experiments and to control for the environmental effects, animals with the same tail attachment and housing conditions, but not suspended (NS), were compared to normally housed (NH) animals. Attachment and housing resulted in weight loss in both genders and phenotypes. Cortical bone loss was observed in the cKO HET males (NH/NS, Ct BV/TV: 90.45±0.72/89.12±0.56%) and both diaphyseal (0.19±0.01/0.17±0.01mm) and metaphyseal (0.10±0.01/0.08±0.01mm) thickness, but not in female cKO HET mice suggesting that male cKO HET mice are susceptible to attachment and housing conditions. These results with transgenic mice emphasizes the importance of proper controls when attributing skeletal responses to unloading. With suspension, cKO HET male mice did not lose bone unlike female cKO HET mice that had greater trabecular bone loss than controls (Ctrl 9%:cKO HET 21% decrease Tb. N; Ctrl 12%:cKO HET 27% increase Tb. Sp.). Suspended and non-suspended mice lost weight compared to normally housed animals. Taken together, the data suggest a protective effect of β-catenin against the effects of stress in males and partial protection against unloading in females

  17. Role of Growth Hormone, Exercise and Serum Phosphorus in Unloaded Bone of Young Rats

    NASA Technical Reports Server (NTRS)

    Arnnaud, Sara B.; Harper, J. S.; Gosselink, K. L.; Navidi, M.; Fung, P.; Grindeland, R. E.; Wade, Charles E. (Technical Monitor)

    1994-01-01

    Growth hormone, known to be stimulated by exercise, is suppressed in rats after space flight and in a ground-based model in which the hind-limbs are unloaded (S). To determine the role of GH in the osteopenia of unloaded bones of S rats, young males were treated with GH combined with insulin-like growth factor-1 (IGF-1), a peptide that mediates the local actions of the hormone. 200 g rats, hypophysectomized (hypox) 17 d earlier, were treated with 1 mg/kg/d GH/IGF-1 (H) or saline (C) in 3 divided daily doses x10 d. Hind-limb bones were unloaded (S), ambulated (A) or exercised (X) by climbing a ladder while carrying a weight. Growth was monitored daily. Tibial growth plate (Tepi) was measured with a micrometer, and femoral (F) area, length, and mineral content (BMC) by DEXA. Parameters of calcium metabolism were measured by autoanalyzer and calciotropic hormones by radioimmunoassay. F bone density, g/square cm, (BMD) or BW were not affected by S in Hypox. However, FBMD was lower in S+H than A+H (p is less than 0.002) and H stimulated whole body growth in S (5.2 g/d) and SX (5.6 g/d) to a lesser extent than in A (6.6 g/d) (p is less than 0.05). Adjusted for BW, Tepi showed the greatest increase in S+H+X (64%), the next highest increase in S+H (50%) and no change in S+X. F area, length and BMC/100 g BW were lower in all H groups than respective C's. By multiple regression analysis, serum phosphorus (Pi) which correlated with Tepi (r = 0.88, p is less than 0.001) and was inversely related to FBMC (r = -0.68, p is less than 0.001) proved to be the most significant determinant of BMC. This illustrates the dependence of osteopenia in S on GH, the maximizing effect of X for epiphyseal growth and the major role of Pi metabolism on BMC in weight bearing bone during growth.

  18. Body Unloading Associated with Space Flight and Bed-rest Impacts Functional Performance

    NASA Technical Reports Server (NTRS)

    Bloomberg, J. J.; Ballard, K. L.; Batson, C. D.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Lee, S. M. C.; Miller, C. A.; Mulavara, A. P.; Peters, B. T.; Phillips, T.; Platts, S. H.; Ploutz-Snyder, L. L.; Reschke, M. F.; Ryder, J. W.; Stenger, M. B.; Taylor, L. C.; Wood, S. J.

    2014-01-01

    The goal of the Functional Task Test study is to determine the effects of space flight on functional tests that are representative of high priority exploration mission tasks and to identify the key underlying physiological factors that contribute to decrements in performance. Ultimately this information will be used to assess performance risks and inform the design of countermeasures for exploration class missions. We are currently conducting studies on both ISS crewmembers and on subjects experiencing 70 days of 6 degrees head-down bed-rest as an analog for space flight. Bed-rest provides the opportunity for us to investigate the role of prolonged axial body unloading in isolation from the other physiological effects produced by exposure to the microgravity environment of space flight. This allows us to parse out the contribution of the body unloading component on functional performance. In this on-going study both ISS crewmembers and bed-rest subjects were tested using an interdisciplinary protocol that evaluated functional performance and related physiological changes before and after 6 months in space and 70 days of 6? head-down bed-rest, respectively. Functional tests included ladder climbing, hatch opening, jump down, manual manipulation of objects and tool use, seat egress and obstacle avoidance, recovery from a fall, and object translation tasks. Crewmembers were tested three times before flight, and on 1, 6 and 30 days after landing. Bed-rest subjects were tested three times before bed-rest and immediately after getting up from bed-rest as well as 1, 6 and 12 days after reambulation. A comparison of bed-rest and space flight data showed a significant concordance in performance changes across all functional tests. Tasks requiring a greater demand for dynamic control of postural equilibrium (i.e. fall recovery, seat egress/obstacle avoidance during walking, object translation, jump down) showed the greatest decrement in performance. Functional tests with

  19. MESSENGER Observations of Extreme Magnetic Tail Loading and Unloading During its Third Flyby of Mercury: Substorms?

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Gloeckler, George; Krimigis, Stamatios M.; McNutt, Ralph L., Jr.; Schriver, David; Solomon, Sean C.; Zurbuchen, Thomas H.

    2010-01-01

    During MESSENGER's third flyby of Mercury on September 29, 2009, a variable interplanetary magnetic field produced a series of several minute enhancements of the tail magnetic field hy factors of approx. 2 to 3.5. The magnetic field flaring during these intervals indicates that they result from loading of the tail with magnetic flux transferred from the dayside magnetosphere. The unloading intervals were associated with plasmoids and traveling compression regions, signatures of tail reconnection. The peak tail magnetic flux during the smallest loading events equaled 30% of the magnetic flux emanating from Mercury, and may have reached 100% for the largest event. In this case the dayside magnetic shielding is reduced and solar wind flux impacting the surface may be greatly enhanced. Despite the intensity of these events and their similarity to terrestrial substorm magnetic flux dynamics, no energetic charged particles with energies greater than 36 keV were observed.

  20. MESSENGER Observations of Extreme Loading and Unloading of Mercury's Magnetic Tail

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Gloeckler, George; Gold, Robert E.; Ho, George C.; Korth, Haje; Krimigis, Stamatios M.; McNutt, Ralph L.; Nittler, Larry R.; Raines, Jim M.; Sarantos, Menelaos; Schriver, David; Solomon, Sean C.; Starr, Richard D.; Travnicek, Pavel M.; Zurbuchen, Thomas H.

    2010-01-01

    During MESSENGER's third flyby of Mercury, a series of 2-3 minute long enhancements of the magnetic field in the planet's magnetotail were observed. Magnetospheric substorms at Earth are powered by similar tail loading, but the amplitude is approximately 10 times less and the durations are 1 hr. These observations of extreme loading imply that the relative intensity of substorms at Mercury must be much larger than at Earth. The correspondence between the duration of tail enhancements and the calculated approximately 2 min Dungey cycle, which describes plasma circulation through Mercury's magnetosphere, suggests that such circulation determines substorm timescale. A key aspect of tail unloading during terrestrial substorms is the acceleration of energetic charged particles. Such signatures are puzzlingly absent from the MESSENGER flyby measurements.

  1. MESSENGER Observations of Extreme Loading and Unloading of Mercury's Magnetic Tail

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Gloeckler, George; Gold, Robert E.; Ho, George C.; Korth, Haje; Krimigis, Stamatios M.; McNutt, Ralph L., Jr.; Nittler, Larry R.; Raines, Jim M.; Sarantos, Menelaos; Schriver, David; Solomon, Sean C.; Starr, Richard D.; Travnicek, Pavel M.; Zurbuchen, Thomas H.

    2010-01-01

    During MESSENGER's third flyby of Mercury, the magnetic field in the planet's magnetotail increased by factors of 2 to 3.5 over intervals of 2 to 3 min. Magnetospheric substorms at Earth are powered by similar tail loading, but the amplitude is approx.10 times less and typical durations are approx.1 hour. The extreme tail loading observed at Mercury implies that the relative intensity of sub storms must be much larger than at Earth. The correspondence between the duration of tail field enhancements and the characteristic time for the Dungey cycle, which describes plasma circulation through Mercury's magnetosphere. suggests that such circulation determines substorm timescale. A key aspect of tail unloading during terrestrial substorms is the acceleration of energetic charged particles, but no acceleration signatures were seen during the MESSENGER flyby.

  2. Application of constitutive model considering nonlinear unloading behavior for Gen.3 AHSS

    NASA Astrophysics Data System (ADS)

    Sun, Li; Wagoner, R. H.

    2013-05-01

    Nonlinear unloading behavior has been reported as an important factor for accurate springback prediction. In this study, a newly proposed special component of strain: "Quasi-Plastic-Elastic" ("QPE") strain was utilized to study the springback behavior of Advanced High Strength Steels (AHSS). Several types of steels, including IF steel, DP780, TRIP780, DP980, TWIP980 and QP980 were considered in this research. The results showed that all the tested steels have following behavior: 1) QPE strain is recoverable, like elastic deformation. 2) It dissipates work, like plastic deformation. A 3-D constitutive model considering QPE behavior was implemented in Abaqus/Standard with shell element and applied to draw-bend springback test for Gen. 3 AHSS, QP980. Predictions for springback using the QPE model were more accurate compared with standard elastic-plastic models.

  3. Molecular dynamics simulations of void coalescence in monocrystalline copper under loading and unloading

    NASA Astrophysics Data System (ADS)

    Peng, Xiaojuan; Zhu, Wenjun; Chen, Kaiguo; Deng, Xiaoliang; Wei, Yongkai

    2016-04-01

    Molecular dynamic calculations are used to examine the anisotropy of voids coalescence under loading and unloading conditions in monocrystalline coppers. In this paper, three typical orientations are investigated, including [100], [110], and [111]. The study shows that voids collapse after the shock loading, leaving two disordered regions at the initial voids sites. Voids re-nucleate in the disordered regions and grow by the emission of dislocations on various slip planes. The dislocation motion contributes to local stress relaxation, which causes the voids to expand to certain radius and then coalesce with each other by dislocation emission. Due to the influence of the anisotropy shear field and different slip systems around the voids, the dislocations emit more easily at specific position, which lead to the anisotropy of void coalescence. A two-dimensional analysis model based on a shear dislocation is proposed and it explains the phenomena of void coalescence in the simulations quite well.

  4. MESSENGER observations of extreme loading and unloading of Mercury's magnetic tail.

    PubMed

    Slavin, James A; Anderson, Brian J; Baker, Daniel N; Benna, Mehdi; Boardsen, Scott A; Gloeckler, George; Gold, Robert E; Ho, George C; Korth, Haje; Krimigis, Stamatios M; McNutt, Ralph L; Nittler, Larry R; Raines, Jim M; Sarantos, Menelaos; Schriver, David; Solomon, Sean C; Starr, Richard D; Trávnícek, Pavel M; Zurbuchen, Thomas H

    2010-08-01

    During MESSENGER's third flyby of Mercury, the magnetic field in the planet's magnetic tail increased by factors of 2 to 3.5 over intervals of 2 to 3 minutes. Magnetospheric substorms at Earth are powered by similar tail loading, but the amplitude is lower by a factor of approximately 10 and typical durations are approximately 1 hour. The extreme tail loading observed at Mercury implies that the relative intensity of substorms must be much larger than at Earth. The correspondence between the duration of tail field enhancements and the characteristic time for the Dungey cycle, which describes plasma circulation through Mercury's magnetosphere, suggests that such circulation determines the substorm time scale. A key aspect of tail unloading during terrestrial substorms is the acceleration of energetic charged particles, but no acceleration signatures were seen during the MESSENGER flyby. PMID:20647422

  5. Relationship between sprint ability and loaded/unloaded jump tests in elite sprinters.

    PubMed

    Loturco, Irineu; DʼAngelo, Ricardo A; Fernandes, Victor; Gil, Saulo; Kobal, Ronaldo; Cal Abad, Cesar C; Kitamura, Katia; Nakamura, Fabio Y

    2015-03-01

    The neuromechanical determinants of sprint running performance have been investigated in team sports athletes and non-elite sprinters. The aim of this study was to quantify the relationships between kinetic and performance parameters, obtained in loaded and unloaded vertical and horizontal jumps, and sprinting in elite athletes. Twenty-two sprinters performed squat jumps, countermovement jumps, horizontal jumps, and jump squats with different loads on a force platform, in addition to a 50-m sprint. Results indicated that jumping height and distance in vertical and horizontal jumps are more strongly correlated (R ≈ 0.81) to sprinting speed than the respective peak forces (R ≈ 0.36). Furthermore, the optimum load generating the maximum power in the jump squat is also highly correlated to sprint performance (R ≈ 0.72). These results reveal that vertical and horizontal jump tests may be used by coaches for assessing and monitoring qualities related to sprinting performance in elite sprinters. PMID:25162648

  6. Role of Glucocorticoids in the Response to Unloading of Muscle Protein and Amino Acid Metabolism

    NASA Technical Reports Server (NTRS)

    Tischler, M. E.; Jaspers, S. R.

    1985-01-01

    Intact control (weight bearing) and suspended rats gained weight at a similar rate during a 6 day period. Adrenaectomized (adx) weight bearing rats gained less weight during this period while adrenalectomized suspended rats showed no significant weight gain. Cortisol treatment of both of these groups of animals caused a loss of body weight. Results from these studies show several important findings: (1) Metabolic changes in the extensor digitorum longus muscle of suspended rats are due primarily to increased circulating gluccorticoids; (2) Metabolic changes in the soleus due to higher steroid levels are probably potentiated by greater numbers of receptors; and (3) Not all metabolic responses in the unloaded soleus muscle are due to direct action of elevated glucocorticoids or increased sensitivity to these hormones.

  7. Effects of Unloading and Reloading on Expressions of Skelatal Muscle Membrane Proteins in Mice

    NASA Astrophysics Data System (ADS)

    Ohno, Y.; Ikuta, A.; Goto, A.; Sugiura, T.; Ohira, Y.; Yoshioka, T.; Goto, K.

    2013-02-01

    Effects of unloading and reloading on the expression levels of tripartite motif-containing 72 (TRIM72) and caveolin-3 (Cav-3) of soleus muscle in mice were investigated. Male C57BL/6J mice (11-week old) were randomly assigned to control and hindlimb-suspended groups. Some of mice in hindlimb-suspended group were subjected to continuous hindlimb suspension (HS) for 2 weeks with or without 7 days of ambulation recovery. Following HS, the muscle weight and protein expression levels of TRIM72 and Cav-3 in soleus were decreased. On the other hand, the gradual increases in muscle mass, TRIM72 and Cav-3 were observed after reloading following HS. Therefore, it was suggested that mechanical loading played a key role in a regulatory system for protein expressions of TRIM72 and Cav-3.

  8. 15 CFR 758.8 - Return or unloading of cargo at direction of BIS, the Office of Export Enforcement or Customs...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false Return or unloading of cargo at direction of BIS, the Office of Export Enforcement or Customs Service. 758.8 Section 758.8 Commerce and... Return or unloading of cargo at direction of BIS, the Office of Export Enforcement or Customs Service....

  9. 15 CFR 758.8 - Return or unloading of cargo at direction of BIS, the Office of Export Enforcement or Customs...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Return or unloading of cargo at direction of BIS, the Office of Export Enforcement or Customs Service. 758.8 Section 758.8 Commerce and... Return or unloading of cargo at direction of BIS, the Office of Export Enforcement or Customs Service....

  10. Preload substantially influences the intervertebral disc stiffness in loading-unloading cycles of compression.

    PubMed

    Schmidt, Hendrik; Shirazi-Adl, Aboulfazl; Schilling, Christoph; Dreischarf, Marcel

    2016-06-14

    Disc hydration is controlled by fluid imbibition and exudation and hence by applied load magnitude and history, internal osmotic pressure and disc conditions. It affects both the internal load distribution and external load-bearing of a disc while variations therein give rise to the disc time-dependent characteristics. This study aimed to evaluate the effect of changes in compression preload magnitude on the disc axial cyclic compression stiffness under physiological loading. After 20h of free hydration, effects of various preload magnitudes (no preload, 0.06 and 0.28MPa, applied for eight hours) and disc-bone preparation conditions on disc height and axial stiffness were investigated using 36 disc-bone and 24 isolated disc (without bony endplates) bovine specimens. After preloading, specimens were subjected to ten loading/unloading cycles each of 7.5min compression at 0.5MPa followed by 7.5min at 0.06MPa. Under 0.06MPa preload, the specimen height losses during high loading periods of cyclic loading were greater than corresponding height recoveries during low loading phases. This resulted in a progressive reduction in the specimen height and increase in its stiffness. Differences between disc height losses in high cyclic loads and between stiffness in both load increase and release phases were significant for 0 and 0.06MPa vs. 0.28MPa preload. Results highlight the significant role of disc preload magnitude/history and hence disc height and hydration on disc stiffness in loading/unloading and disc height loss in loading periods. Proper preconditioning and hence hydration level should be achieved if recovery in height loss similar to in vivo conditions is expected. PMID:27209550

  11. Axial Creep Loading and Unloaded Recovery of the Human Intervertebral Disc and the Effect of Degeneration

    PubMed Central

    O'Connell, Grace D.; Jacobs, Nathan T.; Sen, Sounok; Vresilovic, Edward J.; Elliott, Dawn M.

    2011-01-01

    The intervertebral disc maintains a balance between externally applied loads and internal osmotic pressure. Fluid flow plays a key role in this process, causing fluctuations in disc hydration and height. The objectives of this study were to quantify and model the axial creep and recovery responses of nondegenerate and degenerate human lumbar discs. Two experiments were performed. First, a slow compressive ramp was applied to 2000 N, unloaded to allow recovery for up to 24 hours, and re-applied. The linear-region stiffness and disc height were within 5% of the initial condition for recovery times greater than 8 hours. In the second experiment, a 1000 N creep load was applied for four hours, unloaded recovery monitored for 24 hours, and the creep load repeated. A viscoelastic model comprised of a “fast” and “slow” exponential response was used to describe the creep and recovery, where the fast response is associated with flow in the nucleus pulposus (NP) and endplate, while the slow response is associated with the annulus fibrosus (AF). The study demonstrated that recovery is 3-4X slower than loading. The fast response was correlated with degeneration, suggesting larger changes in the NP with degeneration compared to the AF. However, the fast response comprised only 10-15% of the total equilibrium displacement, with the AF-dominated slow response comprising 40-70%. Finally, the physiological loads and deformations and their associated long equilibrium times confirm that diurnal loading does not represent “equilibrium” in the disc, but that over time the disc is in steady-state. PMID:21783103

  12. Importance of loading and unloading procedures for gecko-inspired controllable adhesives.

    PubMed

    Tamelier, John; Chary, Sathya; Turner, Kimberly L

    2013-08-27

    The importance of loading and unloading procedures has been shown in a variety of different methods for biological dry adhesives, such as the fibers on the feet of the Tokay gecko, but biomimetic dry adhesives have yet to be explored in a similar manner. To date, little work has systematically varied multiple parameters to discern the influence of the testing procedure, and the effect of the approach angle remains uncertain. In this study, a synthetic adhesive is moved in 13 individual approach and retraction angles relative to a flat substrate as well as 9 different shear lengths to discern how loading and unloading procedures influence the preload, adhesion, and shear/friction forces supported. The synthetic adhesive, composed of vertical 10 μm diameter semicircular poly(dimethylsiloxane) fibers, is tested against a 4 mm diameter flat glass puck on a home-built microtribometer using both vertical approach and retraction tests and angled approach and retraction tests. The results show that near maximum adhesion and friction can be obtained for most approach and retraction angles, provided that a sufficient shear length is performed. The results also show that the reaction forces during adhesive placement can be significantly reduced by using specific approach angles, resulting for the vertical fibers in a 38-fold increase in the ratio of adhesion force to preload force, μ', when compared to that when using a vertical approach. These results can be of use to those currently researching gecko-inspired adhesives when designing their testing procedures and control algorithms for climbing and perching robots. PMID:23875720

  13. EXTRACORPOREAL MEMBRANE OXYGENATION vs. COUNTERPULSATILE, PULSATILE, AND CONTINUOUS LEFT VENTRICULAR UNLOADING FOR PEDIATRIC MECHANICAL CIRCULATORY SUPPORT

    PubMed Central

    Bartoli, Carlo R.; Koenig, Steven C.; Ionan, Constantine; Gillars, Kevin J.; Mitchell, Mike E.; Austin, Erle H.; Gray, Laman A.; Pantalos, George M.

    2014-01-01

    OBJECTIVE Despite progress with adult ventricular assist devices (VADs), limited options exist to support pediatric patients with life-threatening heart disease. Extracorporeal membrane oxygenation (ECMO) remains the clinical standard. To characterize (patho)physiologic responses to different modes of mechanical unloading of the failing pediatric heart, ECMO was compared to either intraaortic balloon pump (IABP), pulsatile-flow (PF)VAD, or continuous-flow (CF)VAD support in a pediatric heart failure model. DESIGN Experimental. SETTING Large animal laboratory operating room. SUBJECTS Yorkshire piglets (n=47, 11.7±2.6 kg). INTERVENTIONS In piglets with coronary ligation-induced cardiac dysfunction, mechanical circulatory support devices were implanted and studied during maximum support. MEASUREMENTS and MAIN RESULTS Left ventricular, right ventricular, coronary, carotid, systemic arterial, and pulmonary arterial hemodynamics were measured with pressure and flow transducers. Myocardial oxygen consumption and total-body oxygen consumption (VO2) were calculated from arterial, venous, and coronary sinus blood sampling. Blood flow was measured in 17 organs with microspheres. Paired student t-tests compared baseline and heart failure conditions. One-way repeated-measures ANOVA compared heart failure, device support mode(s), and ECMO. Statistically significant (p<0.05) findings included: 1) improved left ventricular blood supply/demand ratio during PFVAD, CFVAD, and ECMO but not IABP support, 2) improved global myocardial blood supply/demand ratio during PFVAD, and CFVAD but not IABP or ECMO support, and 3) diminished pulsatility during ECMO and CFVAD but not IABP and PFVAD support. A profile of systems-based responses was established for each type of support. CONCLUSIONS Each type of pediatric VAD provided hemodynamic support by unloading the heart with a different mechanism that created a unique profile of physiological changes. These data contribute novel, clinically

  14. Spaceflight and hind limb unloading induce similar changes in electrical impedance characteristics of mouse gastrocnemius muscle

    PubMed Central

    Sung, M.; Li, J.; Spieker, A.J.; Spatz, J.; Ellman, R.; Ferguson, V.L.; Bateman, T.A.; Rosen, G.D.; Bouxsein, M.; Rutkove, S.B.

    2014-01-01

    Objective To assess the potential of electrical impedance myography (EIM) to serve as a marker of muscle fiber atrophy and secondarily as an indicator of bone deterioration by assessing the effects of spaceflight or hind limb unloading. Methods In the first experiment, 6 mice were flown aboard the space shuttle (STS-135) for 13 days and 8 earthbound mice served as controls. In the second experiment, 14 mice underwent hind limb unloading (HLU) for 13 days; 13 additional mice served as controls. EIM measurements were made on ex vivo gastrocnemius muscle. Quantitative microscopy and areal bone mineral density (aBMD) measurements of the hindlimb were also performed. Results Reductions in the multifrequency phase-slope parameter were observed for both the space flight and HLU cohorts compared to their respective controls. For ground control and spaceflight groups, the values were 24.7±1.3°/MHz and 14.1±1.6°/MHz, respectively (p=0.0013); for control and HLU groups, the values were 23.9±1.6°/MHz and 19.0±1.0°/MHz, respectively (p=0.014). This parameter also correlated with muscle fiber size (ρ=0.65, p=0.011) for spaceflight and hind limb aBMD (ρ=0.65, p=0.0063) for both groups. Conclusions These data support the concept that EIM may serve as a useful tool for assessment of muscle disuse secondary to immobilization or microgravity. PMID:24292610

  15. 49 CFR 176.108 - Supervision of Class 1 (explosive) materials during loading, unloading, handling and stowage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Supervision of Class 1 (explosive) materials... TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials § 176.108 Supervision of Class 1 (explosive) materials during loading, unloading, handling...

  16. 9 CFR 72.17 - Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Unloading noninfected cattle for rest... cattle for rest, feed, and water only, permitted in authorized pens for such purpose. (a) Specifications for construction and maintenance. Cattle of the free area, and cattle of the quarantined area...

  17. 40 CFR Table 2 to Subpart Cccccc... - Applicability Criteria and Management Practices for Gasoline Cargo Tanks Unloading at Gasoline...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Practices for Gasoline Cargo Tanks Unloading at Gasoline Dispensing Facilities With Monthly Throughput of 100,000 Gallons of Gasoline or More 2 Table 2 to Subpart CCCCCC of Part 63 Protection of Environment... Pollutants for Source Category: Gasoline Dispensing Facilities Pt. 63, Subpt. CCCCCC, Table 2 Table 2...

  18. 40 CFR Table 2 to Subpart Cccccc... - Applicability Criteria and Management Practices for Gasoline Cargo Tanks Unloading at Gasoline...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Practices for Gasoline Cargo Tanks Unloading at Gasoline Dispensing Facilities With Monthly Throughput of 100,000 Gallons of Gasoline or More 2 Table 2 to Subpart CCCCCC of Part 63 Protection of Environment... Pollutants for Source Category: Gasoline Dispensing Facilities Pt. 63, Subpt. CCCCCC, Table 2 Table 2...

  19. 40 CFR Table 2 to Subpart Cccccc... - Applicability Criteria and Management Practices for Gasoline Cargo Tanks Unloading at Gasoline...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Practices for Gasoline Cargo Tanks Unloading at Gasoline Dispensing Facilities With Monthly Throughput of 100,000 Gallons of Gasoline or More 2 Table 2 to Subpart CCCCCC of Part 63 Protection of Environment... Pollutants for Source Category: Gasoline Dispensing Facilities Pt. 63, Subpt. CCCCCC, Table 2 Table 2...

  20. 40 CFR Table 2 to Subpart Cccccc... - Applicability Criteria and Management Practices for Gasoline Cargo Tanks Unloading at Gasoline...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Practices for Gasoline Cargo Tanks Unloading at Gasoline Dispensing Facilities With Monthly Throughput of 100,000 Gallons of Gasoline or More 2 Table 2 to Subpart CCCCCC of Part 63 Protection of Environment... Pollutants for Source Category: Gasoline Dispensing Facilities Pt. 63, Subpt. CCCCCC, Table 2 Table 2...

  1. Stress-displacement relation of fiber for fiber-reinforced ceramic composites during (indentation) loading and unloading

    SciTech Connect

    Hsueh, C.; Ferber, M.K.; Becher, P.F. )

    1989-11-01

    The stress-displacement relation of the fiber is analyzed for fiber-reinforced ceramic composites during axial compressive loading (indentation) and unloading on the exposed end of an embedded fiber. An unbonded fiber/matrix interface subject to Coulomb friction and residual radial clamping stresses is considered in the present study. The results show that the stress-displacement curves during loading and unloading can be used to evaluate the magnitude of the clamping stress, the coefficient of friction, and the frictional stress distribution at the interface. Specifically, in the absence of Poisson's effect (i.e., when Poisson's ratio of the fiber is zero), the interfacial shear stress is constant, the loading curve is parabolic, and, after complete unloading, the residual fiber displacement equals half of the maximum fiber displacement at the peak loading stress. In the presence of Poisson's effect, the interfacial shear stress is not constant, and, after complete unloading, the residual fiber displacement is less than half of the maximum fiber displacement at the peak loading stress.

  2. 9 CFR 72.17 - Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Unloading noninfected cattle for rest, feed, and water only, permitted in authorized pens for such purpose. 72.17 Section 72.17 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE INTERSTATE TRANSPORTATION OF ANIMALS (INCLUDING POULTRY)...

  3. Critical Compressive Stress for Flat Rectangular Plates Supported Along All Edges and Elastically Restrained Against Rotation along the Unloaded Edges

    NASA Technical Reports Server (NTRS)

    Lundquist, Eugene E; Stowell, Elbridge Z

    1942-01-01

    A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in flat rectangular plates supported along all edges and, in addition, elastically restrained against rotation along the unloaded edges. The mathematical derivations of the formulas required in the construction of the chart are given.

  4. 40 CFR Table 2 to Subpart Cccccc... - Applicability Criteria and Management Practices for Gasoline Cargo Tanks Unloading at Gasoline...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 14 2010-07-01 2010-07-01 false Applicability Criteria and Management Practices for Gasoline Cargo Tanks Unloading at Gasoline Dispensing Facilities With Monthly Throughput of 100,000 Gallons of Gasoline or More 2 Table 2 to Subpart CCCCCC of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

  5. The declined phosphorylation of Hsp27 in rat cardiac muscle after simulated microgravity induced by hindlimb unloading

    NASA Astrophysics Data System (ADS)

    Yuan, Ming; Jiang, Shizhong; Li, Zhili; Yuan, Min; Dong, Weijun

    Many studies have shown that simulated microgravity induced by hindlimb unloading can decrease the contractility of rat cardiac muscle however the mechanisms responsible for which remain unclear Actin polymerization which can be regulated by Hsp27 has important role in the transmission of stress force during the contraction of cardiac muscle In this study western blot analysis was used to detect the expression of Hsp27 and phosphorylated Hsp27 FAK and phosphorylated FAK P38 MAPK and phosphorylated P38 MAPK in rat cardiac muscle after 14d hindlimb unloading The results showed that the phosphorylation levels of both Hsp27 and P38 MAPK were declined significantly which may decrease actin polymerization and inhibit the transmission of stress force during the contraction of rat cardiac muscle after hindlimb unloading However the phosphorylation level of FAK was not declined significantly in cardiac muscle The results suggested that the declined phosphorylation level of Hsp27 which may be ascribable to the decline of contractility of rat cardiac muscle after 14d hindlimb unloading may be induced by the declined phosphorylation level of P38 MAPK but not phosphorylation level of FAK

  6. Hind Limb Unloading Model Alters Nuclear Factor kappa B and Activator Protein-1 Signaling in Mouse Brain

    NASA Astrophysics Data System (ADS)

    Ramesh, Govindarajan; Vani, Vani; Renard, Renard; Vera, Vera; Wilosn, Wilosn; Ramesh, Govindarajan

    Microgravity induces inflammatory response and also modulates immune functions, which may increase oxidative stress. Exposure to the microgravity environment induces adverse neurological effects. However, there is little research exploring the etiology of neurological effects of exposure to this environment. To explore this area we evaluated changes in Nuclear Factor kappa B, Activator Protein 1, MAPP kinase and N terminal c-Jun kinase in mouse brain exposed to a simulated microgravity environment using the hindlimb unloading model. BALB/c male mice were randomly assigned to hindlimb unloading group (n=12) and control group (n=12) to simulate a microgravity environment, for 7 days. Changes observed in NF-κB, AP- 1 DNA binding, MAPKK and N terminal c-Jun kinase were measured using electrophoretic mobility shift assay (EMSA) and western blot analysis and compared to unexposed brain regions. Hindlimb unloading exposed mice showed significant increases in generated NF-κB, AP-1, MAPKK and Kinase in all regions of the brain exposed to hindlimb unloading as compared to the control brain regions. Results suggest that exposure to simulated microgravity can induce expression of certain transcription factors and protein kinases. This work was supported by funding from NASA NCC 9-165. 504b030414000600080000002100828abc13fa0000001c020000130000005b436f6e74656e745f54797065735d2e78

  7. Regulation of eIF2α phosphorylation in hindlimb-unloaded and STS-135 space-flown mice

    NASA Astrophysics Data System (ADS)

    Zhao, Liming; Tanjung, Nancy; Swarnkar, Gaurav; Ledet, Eric; Yokota, Hiroki

    2012-09-01

    Various environmental stresses elevate the phosphorylation level of eukaryotic translation initiation factor 2 alpha (eIF2α) and induce transcriptional activation of a set of stress responsive genes such as activating transcription factors 3 and 6 (ATF3 and ATF6), CCAAT/enhancer-binding protein homologous protein (CHOP), and Xbp1 (X-box binding protein 1). These stress sources include radiation, oxidation, and stress to the endoplasmic reticulum, and it is recently reported that unloading by hindlimb unloading is such a stress source. No studies, however, have examined the phosphorylation level of eIF2α (eIF2α-p) using skeletal samples that have experienced microgravity in space. In this study we addressed a question: Does a mouse tibia flown in space show altered levels of eIF2α-p? To address this question, we obtained STS-135 flown samples that were harvested 4-7 h after landing. The tibia and femur isolated from hindlimb unloaded mice were employed as non-flight controls. The effects of loading were also investigated in non- flight controls. Results indicate that the level of eIF2α-p of the non-flight controls was elevated during hindlimb unloading and reduced after being released from unloading. Second, the eIF2α-p level of space-flown samples was decreased, and mechanical loading to the tibia caused the reduction of the eIF2α-p level. Third, the mRNA levels of ATF3, ATF6, and CHOP were lowered in space-flown samples as well as in the non-flight samples 4-7 h after being released from unloading. Collectively, the results herein indicated that a release from hindlimb unloading and a return to normal weight environment from space provided a suppressive effect to eIF2α-linked stress responses and that a period of 2-4 h is sufficient to induce this suppressive outcome.

  8. Radiation and mechanical unloading effects on mouse vertebral bone: Ground-based models of the spaceflight environment

    NASA Astrophysics Data System (ADS)

    Alwood, Joshua Stewart

    Astronauts on long-duration space missions experience increased ionizing radiation background levels and occasional acute doses of ionizing radiation from solar particle events, in addition to biological challenges introduced by weightlessness. Previous research indicates that cancer radiotherapy damages bone marrow cell populations and reduces mechanical strength of bone. However, the cumulative doses in radiotherapy are an order of magnitude or greater than dose predictions for long-duration space missions. Further detriments to the skeletal system are the disuse and mechanical unloading experienced during weightlessness, which causes osteopenia in weight-bearing cancellous bone (a sponge-like bony network of rods, plates and voids) and cortical bone (dense, compact bone). Studies of radiation exposure utilizing spaceflight-relevant types and doses, and in combination with mechanical unloading, have received little attention. Motivated by the future human exploration of the solar system, the effects of acute and increased background radiation on astronaut skeletal health are important areas of study in order to prevent osteopenic deterioration and, ultimately, skeletal fracture. This dissertation addresses how spaceflight-relevant radiation affects bone microarchitecture and mechanical properties in the cancellous-rich vertebrae and compares results to that of mechanical unloading. In addition, a period of re-ambulation is used to test whether animals recover skeletal tissue after irradiation. Whether radiation exposure displays synergism with mechanical unloading is further investigated. Finite element structural and statistical analyses are used to investigate how changes in architecture affect mechanical stress within the vertebra and to interpret the mechanical testing results. In this dissertation, ground-based models provide evidence that ionizing radiation, both highly energetic gamma-rays and charged iron ions, resulted in a persistent loss of cancellous

  9. Overexpression of IGF-I in skeletal muscle of transgenic mice does not prevent unloading-induced atrophy

    NASA Technical Reports Server (NTRS)

    Criswell, D. S.; Booth, F. W.; DeMayo, F.; Schwartz, R. J.; Gordon, S. E.; Fiorotto, M. L.

    1998-01-01

    This study examined the association between local insulin-like growth factor I (IGF-I) overexpression and atrophy in skeletal muscle. We hypothesized that endogenous skeletal muscle IGF-I mRNA expression would decrease with hindlimb unloading (HU) in mice, and that transgenic mice overexpressing human IGF-I (hIGF-I) specifically in skeletal muscle would exhibit less atrophy after HU. Male transgenic mice and nontransgenic mice from the parent strain (FVB) were divided into four groups (n = 10/group): 1) transgenic, weight-bearing (IGF-I/WB); 2) transgenic, hindlimb unloaded (IGF-I/HU); 3) nontransgenic, weight-bearing (FVB/WB); and 4) nontransgenic, hindlimb unloaded (FVB/HU). HU groups were hindlimb unloaded for 14 days. Body mass was reduced (P < 0.05) after HU in both IGF-I (-9%) and FVB mice (-13%). Contrary to our hypothesis, we found that the relative abundance of mRNA for the endogenous rodent IGF-I (rIGF-I) was unaltered by HU in the gastrocnemius (GAST) muscle of wild-type FVB mice. High-level expression of hIGF-I peptide and mRNA was confirmed in the GAST and tibialis anterior (TA) muscles of the transgenic mice. Nevertheless, masses of the GAST and TA muscles were reduced (P < 0.05) in both FVB/HU and IGF-I/HU groups compared with FVB/WB and IGF-I/WB groups, respectively, and the percent atrophy in mass of these muscles did not differ between FVB and IGF-I mice. Therefore, skeletal muscle atrophy may not be associated with a reduction of endogenous rIGF-I mRNA level in 14-day HU mice. We conclude that high local expression of hIGF-I mRNA and peptide in skeletal muscle alone cannot attenuate unloading-induced atrophy of fast-twitch muscle in mice.

  10. Effects of support unloading on inhibitory processes in motoneurons pools of postural muscles

    NASA Astrophysics Data System (ADS)

    Shigueva, Tatiana; Zakirova, Albina; Tomilovskaya, Elena

    The purpose of the study was to investigate the effect of support unloading on characteristics of shin extensor muscles (m.soleus and m.gastrocnemius lat.) motor units` (MU) activity evoked by electrical stimulation and intensity of spinal inhibitory processes. Conditions of support unloading were reproduced by "dry" immersion (DI), that it seen to be is the most adequate ground simulation model of weightlessness [Shulzhenko E.B. et al, 1976]. The experiments were performed with participation of 10 healthy men of 20-27 years old. The subjects were divided into 2 groups. In the first one (control group) the subjects stayed in DI for 3 days without any other influences; in the second one (experimental group) in the course of DI the mechanical stimulation of soles’ support zones in the regimen of locomotion was applied daily for 20 min at the beginning of each hour for 6 hours per day [Kozlovskaya I.B., 2007]. MUs’ activity of shin muscles (mm. gastrocnemius lat. and soleus) was recorded with needle concentric electrodes during execution of the task of maintaining a small plantar flexion effort (not stronger than 7% of maximal voluntary contraction force). Single electrical pulses 0,1 ms duration were applied to n.tibialis during spontaneous MU activity. The duration of silent period (SP) following H-reflex response and presence of rebound phenomenon - an increase of MU activity at the end of SP, that is usually observed under normal conditions and reflects trace of inhibitory and excitatory processes in motoneurons pools, were analyzed [Person R.S., 1985]. Experiments were performed before, on the 2nd and 3d day of DI and on the 2nd day after its accomplishment. The Wilcoxon nonparametric criteria were used for statistical data analysis. Exposure to the conditions of support unloading was followed by significant decline of SP duration. The mean of SP duration in shin muscles before DI was 227±31,4 ms. On the 2nd and 3rd days of DI in the control group it

  11. Lithosphere stress changes due to groundwater unloading in North China Plain

    NASA Astrophysics Data System (ADS)

    Pang, Yajin; Zhang, Huai; Shi, Yaolin

    2015-04-01

    During the past 50 years, excessive groundwater pumping has led to the continuous decline of groundwater table in North China Plain, which becomes one of the global hotspots of groundwater depletion. Over most of the rural areas of the plain, the shallow aquifer has experienced a water-table decline of more than 15m, with greater declines up to 50m in most urban centres, such as Beijing, Tangshan, Shijiangzhuang and so forth in 1960-2000. The entire groundwater depletion area covers a total area of approximately 56,273 km2 , more than 40% of the North China Plain. The vast area of enormous groundwater exploitation in North China Plain will definitely unload the lithosphere and create stress perturbations, the problem is if the stresses change large enough to affect tectonic activities. In this essay, we set up a 3 dimensional numerical visco-elastic model to discuss the effect of groundwater over-pumping on the lithosphere deformation and stress state in North China Plain. Based on the records of total groundwater-table decline during 1960-2010 in North China Plain, we estimate the accumulated deformation and lithosphere stress due to unloading of human-induced groundwater depletion. The area in the model ranges from 34° To 42°N, and 112° To 119°E, including the major groundwater depression cones in North China Plain. According to the simulating result, the maximum surface vertical uplift caused by groundwater unloading is 8cm. Meanwhile cumulative horizontal crustal stress changes near the surface goes up to 100kPa, and up to 40kPa at 15km depth where most earthquakes occurred in this area. The tectonic compressive stress rate is about 0.25kPa per year. Therefore, the stress changes due to groundwater pumping is significant compared with the tectonic driven stress changes. As China developed rapidly since 1978, the groundwater table mainly declined after 1978. Taking the earthquake catalog in the vicinity of groundwater depression zone into consideration, we

  12. A reproducible radiation delivery method for unanesthetized rodents during periods of hind limb unloading

    NASA Astrophysics Data System (ADS)

    Walb, M. C.; Black, P. J.; Payne, V. S.; Munley, M. T.; Willey, J. S.

    2015-07-01

    Exposure to the spaceflight environment has long been known to be a health challenge concerning many body systems. Both microgravity and/or ionizing radiation can cause acute and chronic effects in multiple body systems. The hind limb unloaded (HLU) rodent model is a ground-based analogue for microgravity that can be used to simulate and study the combined biologic effects of reduced loading with spaceflight radiation exposure. However, studies delivering radiation to rodents during periods of HLU are rare. Herein we report the development of an irradiation protocol using a clinical linear accelerator that can be used with hind limb unloaded, unanesthetized rodents that is capable of being performed at most academic medical centers. A 30.5 cm × 30.5 cm × 40.6 cm rectangular chamber was constructed out of polymethyl methacrylate (PMMA) sheets (0.64 cm thickness). Five centimeters of water-equivalent material were placed outside of two PMMA inserts on either side of the rodent that permitted the desired radiation dose buildup (electronic equilibrium) and helped to achieve a flatter dose profile. Perforated aluminum strips permitted the suspension dowel to be placed at varying heights depending on the rodent size. Radiation was delivered using a medical linear accelerator at an accelerating potential of 10 MV. A calibrated PTW Farmer ionization chamber, wrapped in appropriately thick tissue-equivalent bolus material to simulate the volume of the rodent, was used to verify a uniform dose distribution at various regions of the chamber. The dosimetry measurements confirmed variances typically within 3%, with maximum variance <10% indicated through optically stimulated luminescent dosimeter (OSLD) measurements, thus delivering reliable spaceflight-relevant total body doses and ensuring a uniform dose regardless of its location within the chamber. Due to the relative abundance of LINACs at academic medical centers and the reliability of their dosimetry properties, this

  13. Rat soleus muscle satellite cells during the recovery after gravitational unloading

    NASA Astrophysics Data System (ADS)

    Turtikova, Olga; Shenkman, Boris; Altaeva, Erzhena; Leinsoo, Toomas

    In this study the attempt was made to assess alterations of rat soleus satellite cell (SC) population during muscle regrowth after 14-day gravitational unloading (using the hindlimb suspension model). Myofiber size increases during the recovery period. SCs are supposed to participate in muscle growth by fusion with myofibers and supplying them with new myonuclei [Mitchell PO, Pavlath GK, 2001; Oishi Y., 2008]. Other points of view are known about SC participation in the recovery of atrophied muscle mass during the readaptation period [Bruusgaard J.C. et al., 2011; Jackson JR et al., 2012]. After 2 weeks of hindlimb suspension mki67 expression was fivefold lower as compared to control animals and increased gradually up to 28 times by the day 7 of reloading. Cdh15 was decreased after hindlimb unloading and rose from the 1st day of reloading. The expression reached control level to the day 7th of reloading. Cellular response was going on concurrently with the spike of IGF-1 blood level and the increase in muscle IGF-1 concentration. It is possible that in the early days of reloading period differentiation and fusion of satellite cells which were active by the end of hindlimb suspension occurred. Satellite cell incorporation was assessed by counting the amount of BrdU+ myonuclei under myofiber dystrophin layer. It came more intensively in the 1st day of readaptation. It is in accordance with the 4,5 time increase in myogenin expression as compared to hindlimb suspended animals detected at the same time point. Myogenin expression 3 fold decreased by 3rd day of readaptation. We observed only the tendency of resizing but no significant changes in in myonuclear domain size. The number of myonuclei per myofiber cross section was decreased after hindlimb suspension and was not restored by the day 14th of readaptation. Cdh15 and myogenin expression at some extent stabilized after 7 days of readaptation, but high mki67 level pointed to intensive proliferation, which could

  14. Effects of Hind Limb Unloading on Pharmacokinetics of Procainamide in Mice

    NASA Technical Reports Server (NTRS)

    Risin, Semyon A.; Dasgupta, Amitava; Ramesh, Govindarajan T.; Risin, Diana

    2007-01-01

    The pharmacokinetics (PK) of medications administered to astronauts could be altered by the conditions in space. It is prudent to expect that low gravity and free floating (and associated hemodynamic changes) could affect the absorption, distribution, metabolism and excretion of the drugs. Knowledge of these alterations is essential for adjusting the dosage and the regimen of drug administration. Among the medications of special interest are the cardiovascular drugs, especially the antiarrhythmic agents. In this study we used hind limb unloaded (HLU) mice as a model to investigate possible changes in the PK of a common antiarrhythmic drug procainamide (PA). Prior to drug administration the experimental animals were tail suspended for 24 hours and the control animals were kept free. PA (150-250 mg per kg) was given orally by a gavage procedure. After that the experimental mice were kept suspended for additional 1, 2, 3 and 6 hours. At these time points the serum concentration of PA and N-acetyl-procainamide (NAPA), an active metabolite which is formed by N-acetyltransferase in the liver, were measured by the fluorescence polarization immunoassay (FPIA) on the AxSYM autoanalyzer (Abbott Laboratories, Abbott Park, IL). The serum level of PA in HLU mice at 1 hour after administration was almost 40% lower than in controls. At 2-3 hours the difference still maintained, however, it was not statistically significant; at 6 hours no difference was detected. The level of NAPA in HLU mice was slightly lower at 1 and 2 hours but the difference did not reach statistical significance. The estimated PA half-life time in HLU mice was almost 55% longer than in control animals. These results confirm that hind limb unloading and related hemodynamic changes significantly alter the PK of PA. The effects are most likely primarily associated with a decrease in the drug absorption, especially within the first two hours after administration. At the same time prolongation of the PA half

  15. A proportional assist ventilator to unload respiratory muscles experimentally during exercise in humans.

    PubMed

    Dominelli, Paolo B; Henderson, William R; Sheel, A William

    2016-06-01

    What is the central question of this study? Can a modern proportional assist ventilator (PAV) function sufficiently well to unload the respiratory muscles during exercise? What is the main finding and its importance? A PAV can be constructed with contemporary hardware and software and be used at all exercise intensities to unload the respiratory muscles by up to 70%. Previously, PAVs have allowed researchers to address many fundamental physiological problems in clinical and healthy populations, but those versions are no longer functional or available. We describe the creation of a PAV that permits researchers to use it as an experimental tool. Manipulation of the normally occurring work of breathing (WOB) during exercise can provide insights into whole-body regulatory mechanisms in clinical patients and healthy subjects. One method to reduce the WOB uses a proportional assist ventilator (PAV). Suitable commercially available units are not capable of being used during heavy exercise. This investigation was undertaken in order to create a PAV and assess the degree to which the WOB could be reduced during exercise. A PAV works by creating a positive mouth pressure (Pm ) during inspiration, which consequently reduces the WOB. Spontaneous breathing patterns can be maintained, and the amplitude of Pm is calculated using the equation of motion and predetermined proportionality constants. We generated positive Pm using a breathing apparatus consisting of rigid tubing, solenoid valves to control the airflow direction and a proportional valve connected to compressed gas. Healthy male and female subjects were able to use the PAV successfully while performing cycling exercise over a range of intensities (50-100% of maximal workload) for different durations (from 30 s to 20 min) and different protocols (constant versus progressive workload). Inspiratory WOB was reduced up to 90%, while total WOB was reduced by 70%. The greatest reduction in WOB (50-75%) occurred during

  16. A Reproducible Radiation Delivery Method for Unanesthetized Rodents during Periods of Hind Limb Unloading

    PubMed Central

    Walb, M.C.; Black, P.J.; Payne, V.S.; Munley, M.T.; Willey, J.S.

    2015-01-01

    Exposure to the spaceflight environment has long been known to be a health challenge concerning many body systems. Both microgravity and/or ionizing radiation can cause acute and chronic effects in multiple body systems. The hind limb unloaded (HLU) rodent model is a ground-based analogue for microgravity that can be used to simulate and study the combined biologic effects of reduced loading with spaceflight radiation exposure. However, studies delivering radiation to rodents during periods of HLU are rare. Herein we report the development of an irradiation protocol using a clinical linear accelerator that can be used with hind limb unloaded, unanesthetized rodents that is capable of being performed at most academic medical centers. A 30.5 cm × 30.5 cm × 40.6 cm rectangular chamber was constructed out of polymethyl methacrylate (PMMA) sheets (0.64 cm thickness). Five cm of water-equivalent material were placed outside of two PMMA inserts on either side of the rodent that permitted the desired radiation dose buildup (electronic equilibrium) and helped to achieve a flatter dose profile. Perforated aluminum strips permitted the suspension dowel to be placed at varying heights depending on the rodent size. Radiation was delivered using a medical linear accelerator at an accelerating potential of 10 MV. A calibrated PTW Farmer ionization chamber, wrapped in appropriately thick tissue-equivalent bolus material to simulate the volume of the rodent, was used to verify a uniform dose distribution at various regions of the chamber. The dosimetry measurements confirmed variances typically within 3%, with maximum variance <10% indicated through optically stimulated luminescent dosimeter (OSLD) measurements, thus delivering reliable spaceflight-relevant total body doses and ensuring a uniform dose regardless of its location within the chamber. Due to the relative abundance of LINAC’s at academic medical centers and the reliability of their dosimetry properties, this method

  17. Programmed administration of parathyroid hormone increases bone formation and reduces bone loss in hindlimb-unloaded ovariectomized rats

    NASA Technical Reports Server (NTRS)

    Turner, R. T.; Evans, G. L.; Cavolina, J. M.; Halloran, B.; Morey-Holton, E.

    1998-01-01

    Gonadal insufficiency and reduced mechanical usage are two important risk factors for osteoporosis. The beneficial effects of PTH therapy to reverse the estrogen deficiency-induced bone loss in the laboratory rat are well known, but the influence of mechanical usage in this response has not been established. In this study, the effects of programed administration of PTH on cancellous bone volume and turnover at the proximal tibial metaphysis were determined in hindlimb-unloaded, ovariectomized (OVX), 3-month-old Sprague-Dawley rats. PTH was administered to weight-bearing and hindlimb-unloaded OVX rats with osmotic pumps programed to deliver 20 microg human PTH (approximately 80 microg/kg x day) during a daily 1-h infusion for 7 days. Compared with sham-operated rats, OVX increased longitudinal and radial bone growth, increased indexes of cancellous bone turnover, and resulted in net resorption of cancellous bone. Hindlimb unloading of OVX rats decreased longitudinal and radial bone growth, decreased osteoblast number, increased osteoclast number, and resulted in a further decrease in cancellous bone volume compared with those in weight-bearing OVX rats. Programed administration of PTH had no effect on either radial or longitudinal bone growth in weight-bearing and hindlimb-unloaded OVX rats. PTH treatment had dramatic effects on selected cancellous bone measurements; PTH maintained cancellous bone volume in OVX weight-bearing rats and greatly reduced cancellous bone loss in OVX hindlimb-unloaded rats. In the latter animals, PTH treatment prevented the hindlimb unloading-induced reduction in trabecular thickness, but the hormone was ineffective in preventing either the increase in osteoclast number or the loss of trabecular plates. Importantly, PTH treatment increased the retention of a baseline flurochrome label, osteoblast number, and bone formation in the proximal tibial metaphysis regardless of the level of mechanical usage. These findings demonstrate that

  18. The Effects of Ligustrazine on the Ca2+ Concentration of Soleus and Gastrocnemius Muscle Fibers in Hindlimb Unloaded Rat

    NASA Astrophysics Data System (ADS)

    Gao, Yunfang; Goswami, Nandu; Du, Bei; Hu, Huanxin; Wu, Xue

    Background:Spaceflight or inactivity (bed rest, limb immobilization, hindlimb unloading) causes skeletal muscle atrophy. Recent studies show that an increase in protein degradation is an important mechanism for disuse atrophy. Furthermore, the calcium overload of disuse-atrophied muscle fiber has been shown to initiate the skeletal muscle proteolysis in disuse atrophy. Ligustrazine (tetramethylpyrazine, TMP), one of the important active ingredient extracted from Chuanxiong, has been shown by our group to increase muscle fiber cross-sectional area in atrophied soleus induced by 14 days hindlimb unloading. However, the underlying mechanisms of ligustrazine effects on disuse-atrophied muscle fibers remain unknown. Objective: We investigated the effects of ligustrazine on the cytoplasmic calcium overloading in soleus and gastrocnemius in 14 days hindlimb unloaded (HU) rats. Methods: Adult female Sprague-Dawley rats were matched for body mass and randomly assigned to three groups (n=8, each group): 1) synchronous control (CON); HU + intragastric water instillation (HU+W); HU + intragastric 60.0 mg kg-1 ligustrazine instillation (HU+Tmp). Laser scanning confocal microscope assessed the concentrations of cytoplasmic calcium ions. Spaceflight disuse atrophy was simulated by hindlimb unloading, provided by tail suspension. Results: 1) Compared with CON, the concentration of soleus intracellular calcium ion in HU+W and HU+Tmp increased 330% and 86% respectively(P<0.01). Compared with HU+W, the concentration of soleus intracellular calcium ion in HU+Tmp decreased by 130%(P<0.01). 2) Compared with CON, the concentration of gastrocnemius intracellular calcium ion in HU+W and HU+Tmp increased 189.8% and 32.1% respectively(P<0.01). Compared with HU+W, the concentration of gastrocnemius intracellular calcium ion in HU+Tmp decreased by 119.3% (P<0.01). Conclusion: After 14 days of hindlimb unloading, cytoplasmic calcium of soleus (slow-twitch muscle) and gastrocnemius (fast

  19. Tracking and Data Relay Satellite (TDRS-3) Range Biases and Momentum Unload Modeling for Terra (EOS-AMI)

    NASA Technical Reports Server (NTRS)

    Ward, Douglas T.

    2001-01-01

    The Flight Dynamics Facility (FDF) reports its performance in meeting Tracking and Data Relay Satellite (TDRS) predicted ephemeris accuracy requirements with TDRS-3. The Terra (Earth Observing System AM-1) satellite has 3-sigma TDRS requirements of 75 m for total position accuracy predicted over one day onboard. The study sample includes selected cases over 21 months after Guam Remote Ground Terminal (GRGT) support started in June 1998. For daily solutions with a 1.5-day prediction span, predicted results of the study were below the Terra requirement by at least 12 m. Refined range bias estimation and modeled momentum unloads are needed to meet Terra's requirements for TDRS-3. Maintained at 275 W longitude over the zone of exclusion, TDRS-3 is analyzed separately from other TDRSs because of its unique tracking data. Only the Bilateration Ranging Transponder (BRT) at Alice Springs (ALS), Australia, and the Telemetry, Tracking and Command (TT&C) system at Guam are used for routine operational tracking data for TDRS-3. Simultaneous batch orbit solutions with three TDRSs and either the Compton Gamma Ray Observatory (GRO) or Terra were done with the Goddard Trajectory Determination System (GTDS) to periodically refine the TT&C and BRT System (BRTS) range biases. As new biases were determined, significant changes were made in estimating the absolute position. FDF achieved similar results using a sequential filter with all operational TDRSs and four user satellites. Definitive accuracy (3-sigma) is expected to be below 50 m. The White Sands Complex (WSC) performs momentum unloads to maintain three-axis stabilized attitude of TDRSs. The relationship between velocity changes (delta-V) and reaction wheel speed changes was empirically determined for roll/yaw unloads. A theoretical relationship was verified and used for pitch unloads. Modeling both pitch and roll/yaw momentum unloads is necessary to meet the 75-m requirement. Moving the orbit solution epoch an hour before a

  20. Investigation of countermeasure for unloading-related muscle plasticity: role of heat stress

    NASA Astrophysics Data System (ADS)

    Goto, K.; Kobayashi, T.; Kojima, A.; Akema, T.; Sugiura, T.; Yamada, S.; Ohira, Y.; Yoshioka, T.

    We have been studying the mechanisms responsible for unloading- or loading-related muscle plasticity. The purpose of the current study was to investigate the effects of heat stress on the growth of mammalian skeletal muscles in vivo. Male Wistar rats (7 weeks old) were divided into two groups: control (n = 24) and heat stress (n = 24). Rats of heat stressed group were exposed to environmental heat stress (41°C for 60 min) in a heat chamber without anesthesia. The soleus muscles were dissected 1, 3, 7, and 14 days after the heat exposure. The wet weights of muscle relative to body weights in heat stressed group were significantly higher than control group 7 days after the exposure (p<0.05). The relative proportion of 5-bromo-2'-deoxyuridine- and proliferating cell nuclear antigen-positive nuclei, that are indicators for the cell proliferation, were increased 1 day after heating (p<0.05). Pax7-positive nuclei, that are indicators for the muscle satellite cells, were also increased 3 day after heat exposure. The expression of phosphorylated p70 S6 kinase was increased 1 day following heat exposure. These results suggest that heat stress could promote cell proliferation, activate satellite cells, and induce muscular hypertrophy.

  1. Aquaporins and unloading of phloem-imported water in coats of developing bean seeds.

    PubMed

    Zhou, Yuchan; Setz, Nathan; Niemietz, Christa; Qu, Hongxia; Offler, Christina E; Tyerman, Stephen D; Patrick, John W

    2007-12-01

    Nutrients are imported into developing legume seeds by mass flow through the phloem, and reach developing embryos following secretion from their symplasmically isolated coats. To sustain homeostasis of seed coat water relations, phloem-delivered nutrients and water must exit seed coats at rates commensurate with those of import through the phloem. In this context, coats of developing French bean seeds were screened for expression of aquaporin genes resulting in cloning PvPIP1;1, PvPIP2;2 and PvPIP2;3. These genes were differentially expressed in all vegetative organs, but exhibited their strongest expression in seed coats. In seed coats, expression was localized to cells of the nutrient-unloading pathway. Transport properties of the PvPIPs were characterized by expression in Xenopus oocytes. Only PvPIP2;3 showed significant water channel activity (Pos = 150-200 microm s(-1)) even when the plasma membrane intrinsic proteins (PIPs) were co-expressed in various combinations. Permeability increases to glycerol, methylamine and urea were not detected in oocytes expressing PvPIPs. Transport active aquaporins in native plasma membranes of seed coats were demonstrated by measuring rates of osmotic shrinkage of membrane vesicles in the presence and absence of mercuric chloride and silver nitrate. The functional significance of aquaporins in nutrient and water transport in developing seeds is discussed. PMID:17927694

  2. Effects of inorganic phosphate analogues on stiffness and unloaded shortening of skinned muscle fibres from rabbit.

    PubMed Central

    Chase, P B; Martyn, D A; Kushmerick, M J; Gordon, A M

    1993-01-01

    1. We examined the effects of aluminofluoride (AlFx) and orthovanadate (Vi), tightly binding analogues of orthophosphate (Pi), on the mechanical properties of glycerinated fibres from rabbit psoas muscle. Maximum Ca(2+)-activated force, stiffness, and unloaded shortening velocity (Vus) were measured under conditions of steady-state inhibition (up to 1 mM of inhibitor) and during the recovery from inhibition. 2. Stiffness was measured using either step or sinusoidal (1 kHz) changes in fibre length. Sarcomere length was monitored continuously by helium-neon laser diffraction during maximum Ca2+ activation. Stiffness was determined from the changes in sarcomere length and the corresponding changes in force. Vus was measured using the slack test method. 3. AlF chi and Vi each reversibly inhibited force, stiffness and Vus. Actively cycling cross-bridges were required for reversal of these inhibitory effects. Recovery from inhibition by AlF chi was 3- to 4-fold slower than that following removal of V1. 4. At various degrees of inhibition, AlF chi and Vi both inhibited steady-state isometric force more than either Vus or stiffness. For both AlF chi and Vi, the relatively greater inhibition of force over stiffness persisted during recovery from steady-state inhibition. We interpret these results to indicate that the cross-bridges with AlF chi or Vi bound are analogous to those which occur early in the cross-bridge cycle. PMID:8487194

  3. MutSα maintains the mismatch repair capability by inhibiting PCNA unloading

    PubMed Central

    Kawasoe, Yoshitaka; Tsurimoto, Toshiki; Nakagawa, Takuro; Masukata, Hisao; Takahashi, Tatsuro S

    2016-01-01

    Eukaryotic mismatch repair (MMR) utilizes single-strand breaks as signals to target the strand to be repaired. DNA-bound PCNA is also presumed to direct MMR. The MMR capability must be limited to a post-replicative temporal window during which the signals are available. However, both identity of the signal(s) involved in the retention of this temporal window and the mechanism that maintains the MMR capability after DNA synthesis remain unclear. Using Xenopus egg extracts, we discovered a mechanism that ensures long-term retention of the MMR capability. We show that DNA-bound PCNA induces strand-specific MMR in the absence of strand discontinuities. Strikingly, MutSα inhibited PCNA unloading through its PCNA-interacting motif, thereby extending significantly the temporal window permissive to strand-specific MMR. Our data identify DNA-bound PCNA as the signal that enables strand discrimination after the disappearance of strand discontinuities, and uncover a novel role of MutSα in the retention of the post-replicative MMR capability. DOI: http://dx.doi.org/10.7554/eLife.15155.001 PMID:27402201

  4. Altered central nervous system processing of baroreceptor input following hindlimb unloading in rats

    NASA Technical Reports Server (NTRS)

    Moffitt, J. A.; Schadt, J. C.; Hasser, E. M.

    1999-01-01

    The effect of cardiovascular deconditioning on central nervous system processing of baroreceptor afferent activity was evaluated following 14 days of hindlimb unloading (HU). Inactin-anesthetized rats were instrumented with catheters, renal sympathetic nerve electrodes, and aortic depressor nerve electrodes for measurement of mean arterial pressure, heart rate, renal sympathetic nerve activity (RSNA), and aortic depressor nerve activity (ADNA). Baroreceptor and baroreflex functions were assessed during infusion of phenylephrine and sodium nitroprusside. Central processing of baroreceptor afferent input was evaluated by linear regression relating RSNA to ADNA. The maximum baroreflex-elicited increase in RSNA was significantly reduced in HU rats (122 +/- 3.8 vs. 144 +/- 4.9% of baseline RSNA), whereas ADNA was not altered. The slope (-0.18 +/- 0.04 vs. -0.40 +/- 0.04) and y-intercept (121 +/- 3.2 vs. 146 +/- 4.3) of the linear regression relating increases in efferent RSNA to decreases in afferent ADNA during hypotension were significantly reduced in HU rats. There were no differences during increases in arterial pressure. Results demonstrate that the attenuation in baroreflex-mediated increases in RSNA following HU is due to changes in central processing of baroreceptor afferent information rather than aortic baroreceptor function.

  5. Review of spaceflight and hindlimb suspension unloading induced sarcomere damage and repair

    NASA Technical Reports Server (NTRS)

    Riley, D. A.; Thompson, J. L.; Krippendorf, B. B.; Slocum, G. R.

    1995-01-01

    Hindlimb suspension unloading (HSU) and spaceflight microgravity induce atrophy of the slow adductor longus muscle fibers which, following reloading, exhibit eccentric contraction (EC)-like lesions (abnormal widening of sarcomeres with A band disruption and excessively wavy, extracted Z lines). These lesions are similar morphologically to those produced in normal muscles after strenuous eccentric exercise. It appears that atrophic muscles exhibit increased susceptibility to eccentric damage because lesions are produced during nonstressful voluntary movements upon return to weightbearing. The EC-like lesions are absent in the unweighted conditions, but appear in HSU rats 15-60 minutes after reloading and in space-flown rates about 4 hrs after landing. By 12 hours, many EC-like lesioned sarcomeres are fully covered by longitudinal patches of Z line-like material which increases in density by 48 hours, producing the so-called "Z line streaming" morphology. In this case, Z line streaming is indicative of rapid repair of damaged sarcomeres rather than the onset of sarcomere breakdown. Immunoelectron microscopy is necessary to determine the composition of this dense material. By 9 days of reloading at 1 gravity, sarcomeres have regained normal structure, except for very rare persistence of faint Z patches. The morphological data indicate that Z patches serve at least two functions: 1) to permit contractile force to be transmitted across the damaged sarcomeres and 2) to provide a scaffold upon which sarcomeres are reconstructed in an active functional muscle.

  6. Quantifiable patterns of limb loading and unloading during hemiparetic gait: Relation to kinetic and kinematic parameters

    PubMed Central

    Raja, Bhavana; Neptune, Richard R.; Kautz, Steven A.

    2016-01-01

    Persons with poststroke hemiparesis are characterized by asymmetry in limb loading (LL) and limb unloading (LU), which has been reported in static and quasi-static tasks but has not been quantified during walking. The purpose of this study was to determine the asymmetry in magnitude and duration of LL and LU in individuals with hemiparesis and its relationship with functional walking status and specific kinematic and kinetic variables during walking. Forty-four participants with chronic hemiparesis walked at their self-selected speeds and eighteen nondisabled control subjects of similar ages walked at predetermined matched speeds while three-dimensional ground reaction forces and body-segment kinematics were recorded. Magnitude of paretic LL was reduced, while duration was increased compared with the nonparetic leg and nondisabled controls walking at matched speeds. The paretic LL and LU was significantly correlated with average leg angle, while the nonparetic leg significantly correlated with average knee angle. Three different patterns of LL and LU were identified (concave, convex, and linear). Individuals with hemiparesis make several biomechanical adjustments that minimize LL of the paretic leg. LL deviations were more pronounced with increased lateral placement of the paretic foot and with decreased functional gait speed. Characterization of these deviations may inspire new strategies for rehabilitation. PMID:23408212

  7. Yield Response of Tantalum for Quasi-Isentropic Loading and Unloading

    NASA Astrophysics Data System (ADS)

    Asay, James R.; Ao, Tommy; Vogler, Tracy J.; Gray, George T., III

    2009-06-01

    Magnetic loading was used to study initial yield strength of pure annealed and cold-worked polycrystalline and single crystal Ta samples for ramp loading at strain rates of ˜10^6/s and the flow strength after peak compression to ˜17 GPa at about 5x10^4/s. For sample thicknesses of 0.5--6 mm, it was found that for annealed pure polycrystalline Ta, the quasi-isentrope elastic limit (IEL) was essentially constant at ˜3.2 GPa with propagation distance. There was no apparent effect of sample purity on precursor amplitude to within experimental uncertainty, although cold-working resulted in loss of the elastic peak and a reduced IEL of ˜1.7 GPa. The flow strength at peak loading stress was estimated from the quasi-elastic unloading and found to increase with peak stress. These results will be discussed in terms of constitutive models for Ta. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.

  8. Swimming Activity Prevents the Unloading Induced Loss of Bone Mass, Architecture, and Strength in Rats

    PubMed Central

    Falcai, Maurício J.; Leoni, Graziela Bianchi; de Sousa Neto, Manoel Damião; Volpon, Jose B.

    2015-01-01

    We investigated whether swimming activity associated with a three-week period of hypoactivity could prevent the deleterious effects of disuse on the tibias of tail-suspended rats. Forty Wistar rats were divided into five groups: (HS) permanently hindlimb suspension rats; (HS + Swim) rats submitted to unloading interrupted by swimming exercise; (HS + WB) hindlimb suspension rats with interruption for regular weight bearing for the same length of time as the HS+Swim rats; (Control) control rats that were allowed regular cage activities; and (Control + Swim) control rats that underwent swimming exercise. At the end of the experiment, bone mineral density, bone strength, and trabecular quantification were analyzed. The hindlimb-suspended rats exhibited bone quality loss (significant decrease in BMD, bone strength, and deterioration of trabecular and cortical bone architecture; decrease in BV/TV, TbN, TbTh, ConnD, CtV, and CtTh; and increase in TbSp) when compared to control rats. In contrast, trained rats showed a significant increase of 43% in bone mass, 29% in bone strength, 58% in trabecular thickness, 85% in bone volume, 27% in trabeculae number, and 30% in cortical volume, when compared to the hindlimb-suspended rats. We conclude that swimming activity not only ameliorates but also fully prevents the deleterious effects on bone quality in osteopenic rats. PMID:26090414

  9. Patterns of global gene expression in rat skeletal muscle during unloading and low-intensity ambulatory activity

    NASA Technical Reports Server (NTRS)

    Bey, Lionel; Akunuri, Nagabhavani; Zhao, Po; Hoffman, Eric P.; Hamilton, Deborah G.; Hamilton, Marc T.

    2003-01-01

    Physical inactivity and unloading lead to diverse skeletal muscle alterations. Our goal was to identify the genes in skeletal muscle whose expression is most sensitive to periods of unloading/reduced physical activity and that may be involved in triggering initial responses before phenotypic changes are evident. The ability of short periods of physical activity/loading as an effective countermeasure against changes in gene expression mediated by inactivity was also tested. Affymetrix microarrays were used to compare mRNA levels in the soleus muscle under three experimental treatments (n = 20-29 rats each): 12-h hindlimb unloading (HU), 12-h HU followed by 4 h of intermittent low-intensity ambulatory and postural activity (4-h reloading), and control (with ambulatory and postural activity). Using a combination of criteria, we identified a small set of genes (approximately 1% of 8,738 genes on the array or 4% of significant expressed genes) with the most reproducible and largest responses to altered activity. Analysis revealed a coordinated regulation of transcription for a large number of key signaling proteins and transcription factors involved in protein synthesis/degradation and energy metabolism. Most (21 of 25) of the gene expression changes that were downregulated during HU returned at least to control levels during the reloading. In surprising contrast, 27 of 38 of the genes upregulated during HU remained significantly above control, but most showed trends toward reversal. This introduces a new concept that, in general, genes that are upregulated during unloading/inactivity will be more resistant to periodic reloading than those genes that are downregulated. This study reveals genes that are the most sensitive to loading/activity in rat skeletal muscle and indicates new targets that may initiate muscle alterations during inactivity.

  10. Climate effects on volcanism: influence on magmatic systems of loading and unloading from ice mass variations, with examples from Iceland.

    PubMed

    Sigmundsson, Freysteinn; Pinel, Virginie; Lund, Björn; Albino, Fabien; Pagli, Carolina; Geirsson, Halldór; Sturkell, Erik

    2010-05-28

    Pressure influences both magma production and the failure of magma chambers. Changes in pressure interact with the local tectonic settings and can affect magmatic activity. Present-day reduction in ice load on subglacial volcanoes due to global warming is modifying pressure conditions in magmatic systems. The large pulse in volcanic production at the end of the last glaciation in Iceland suggests a link between unloading and volcanism, and models of that process can help to evaluate future scenarios. A viscoelastic model of glacio-isostatic adjustment that considers melt generation demonstrates how surface unloading may lead to a pulse in magmatic activity. Iceland's ice caps have been thinning since 1890 and glacial rebound at rates exceeding 20 mm yr(-1) is ongoing. Modelling predicts a significant amount of 'additional' magma generation under Iceland due to ice retreat. The unloading also influences stress conditions in shallow magma chambers, modifying their failure conditions in a manner that depends critically on ice retreat, the shape and depth of magma chambers as well as the compressibility of the magma. An annual cycle of land elevation in Iceland, due to seasonal variation of ice mass, indicates an annual modulation of failure conditions in subglacial magma chambers. PMID:20403840

  11. Expression of IGF-I and Protein Degradation Markers During Hindlimb Unloading and Growth Hormone Administration in Rats

    NASA Astrophysics Data System (ADS)

    Leinsoo, T. A.; Turtikova, O. V.; Shenkman, B. S.

    2013-02-01

    It is known that hindlimb unloading or spaceflight produce atrophy and a number of phenotypic alterations in skeletal muscles. Many of these processes are triggered by the axis growth hormone/insulin-like growth factor I. However growth hormone (GH) and insulin-like growth factor I (IGF-I) expression relationship in rodent models of gravitational unloading is weakly investigated. We supposed the IGF-I is involved in regulation of protein turnover. In this study we examined the IGF-I expression by RT-PCR assay in the rat soleus, tibialis anterior and liver after 3 day of hindlimb suspension with growth hormone administration. Simultaneously were studied expression levels of MuRF-1 and MAFbx/atrogin as a key markers of intracellular proteolysis. We demonstrated that GH administration did not prevent IGF-I expression decreasing under the conditions of simulated weightlessness. It was concluded there are separate mechanisms of action of GH and IGF-I on protein metabolism in skeletal muscles. Gravitational unloading activate proteolysis independently of growth hormone activity.

  12. High-Pressure Quasi-Isentropic Loading and Unloading of Interferometer Windows on the Veloce Pulsed Power Generator

    NASA Astrophysics Data System (ADS)

    Ao, Tommy; Asay, James; Knudson, Marcus; Davis, Jean-Paul

    2007-06-01

    The Isentropic Compression Experiment technique has proven to be a valuable complement to the well-established method of shock compression of condensed matter. However, whereas the high-pressure compression response of window materials has been studied extensively under shock loading, similar knowledge of these materials under ICE loading is limited. We present recent experimental results on the isentropic compression of the high-pressure windows sapphire and LiF. It has previously been observed that c-cut sapphire yields under shock loading at the HEL of ˜15-18GPa, and subsequently loses transparency at higher stresses. However, it will be shown that under isentropic ramp wave loading sapphire appears to remain elastic and transparent at stresses well above 20GPa [D.B. Hayes et al, JAP 94, 2331 (2003)]. LiF is another frequently used window material in isentropic loading and unloading experiments, yet the unloading response of LiF is usually neglected. Research is in progress to measure strength properties of LiF for ramp loading and unloading. It will be shown how the strength of LiF may influence wave profile analysis and thus inferred material strength. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin Company, for the US DOE's NNSA under Contract No.DE-AC04-94AL85000.

  13. Effect of anti-osteoporotic agents on the prevention of bone loss in unloaded bone.

    PubMed

    Siu, Wing Sum; Ko, Chun Hay; Hung, Leung Kim; Lau, Ching Po; Lau, Clara Bik San; Fung, Kwok Pui; Leung, Ping Chung

    2013-10-01

    Pharmaceutical countermeasures to treat disuse osteoporosis are rarely studied. Pharmaceutical studies for the treatment and prevention of osteoporosis depend on the ovariectomized rat model, which is a suitable model for the disease in women. Disuse osteoporosis affects men and women, but there is lack of awareness and relevant pharmaceutical studies for this condition. The objectives of this study were to verify the validity of an unusual tail-suspension rat model in the induction of disuse osteoporosis and subsequent pharmaceutical treatments. This model was created by unloading the hind limbs of the rats in order to create a state of weightlessness in their hindlimb bones. Validation of the model was performed with non-suspended rats. This study included five groups of suspended rats fed with different agents, such as distilled water (control), high-, medium- and low-dose raloxifene and a bisphosphonate (alendronate). The experiment lasted for 28 days. Comparisons were made between the suspended control and treatment groups. Ovariectomized and sham‑operated rats were also included as a reference for bone changes during osteoporosis. Changes in bone mineral density (BMD) at the distal femur and proximal tibia, microarchitecture at the distal femur and biomechanical strength at the diaphyseal femur were studied. Reduction of BMD and deterioration of trabeculae were similar between the suspended control and ovariectomized rats. Loss of BMD induced by tail suspension was reduced most effectively by medium-dose raloxifene. Deterioration of trabecular microarchitecture was also prevented by raloxifene. The tail-suspension rat model is suitable for the study of disuse osteoporosis under the effects of various therapeutic agents. The preventive effects of raloxifene against bone loss under disuse conditions have been demonstrated using this model. PMID:23970373

  14. Left ventricular volume unloading with axial and centrifugal rotary blood pumps.

    PubMed

    Giridharan, Guruprasad A; Koenig, Steven C; Soucy, Kevin G; Choi, Young; Pirbodaghi, Tohid; Bartoli, Carlo R; Monreal, Gretel; Sobieski, Michael A; Schumer, Erin; Cheng, Allen; Slaughter, Mark S

    2015-01-01

    Axial (AX) and centrifugal (CFG) rotary blood pumps have gained clinical acceptance for the treatment of advanced heart failure. Differences between AX and CFG designs and mechanism of blood flow delivery may offer clinical advantages. In this study, pump characteristics, and acute physiologic responses during support with AX (HeartMate II) and CFG (HVAD) left ventricular assist devices (LVAD) were investigated in mock loop and chronic ischemic heart failure bovine models. In the mock loop model, pump performance was characterized over a range of pump speeds (HeartMate II: 7,000-11,000 rpm, HVAD: 2,000-3,600 rpm) and fluid viscosities (2.7 cP, 3.2 cP, 3.7 cP). In the ischemic heart failure bovine model, hemodynamics, echocardiography, and end-organ perfusion were investigated. CFG LVAD had a flatter HQ curve, required less power, and had a more linear flow estimation relation than AX LVAD. The flow estimation error for the AX LVAD (±0.9 L/min at 2.7 cP, ±0.7 L/min at 3.2 cP, ±0.8 L/min at 3.7 cP) was higher than the CFG LVAD (±0.5 L/min at 2.7 cP, ±0.2 L/min at 3.2 cP, ±0.5 L/min at 3.7 cP). No differences in acute hemodynamics, echocardiography, or end-organ perfusion between AX and CFG LVAD over a wide range of support were statistically discernible. These findings suggest no pronounced acute differences in LV volume unloading between AX and CFG LVAD. PMID:25635936

  15. Effects of Loading or Unloading on the Regenerative Potential of Injured Skeletal Muscle in Mice

    NASA Astrophysics Data System (ADS)

    Goto, Katsumasa; Matsuba, Yusuke; Ohno, Yoshitaka; Sugiura, Takao; Hashimoto, Naohiro; Ohira, Yoshinobu; Yoshioka, Toshitada

    2008-06-01

    The present study was performed to investigate the influence of unloading on the regenerative process of injured skeletal muscle. Male mice (C57BL/6J), aged 8 weeks, were randomly divided into 4 groups; normal cage control (CC), cardiotoxin (CTX)-injected (CX), hindlimb suspended (HS), and HS+CX (SX) groups. HS, as the preconditioning, was performed for 2 weeks in group HS and SX. The animals in group CC and CX were maintained in 1-G environment. And then, CTX was injected into soleus muscles bilaterally in CX and SX groups. HS was continued for additional 6 weeks in group HS and SX. Soleus muscles were dissected after 2, 4, and 6 weeks. Wet weight and protein content of soleus in group CX decreased, but recovered to the level of group CC after 6 weeks. Atrophy, caused by 2-week HS, in group HS and SX was maintained throughout the experimental period. The numbers of satellite cells in HS and SX groups after 2, 4, and 6 weeks were lower than those in group CC. The number of satellite cells in CX group was increased by the CTX-injection compared with group CC. On the other hand, satellite cell number in CTX-injected group SX after 2, 4, and 6 weeks were lower than that in group HS. Percentage of fibers with central nuclei, relative to the total muscle fibers, in HS and SX groups at week 6 was higher than that in group CC. That in group CX was also increased at 2nd and 4th week, but was lowered toward the control level after 6 week. It was suggested that loading plays a key role for the activation of the regenerating potential of injured skeletal muscle.

  16. Costamere remodeling with muscle loading and unloading in healthy young men.

    PubMed

    Li, Ruowei; Narici, Marco V; Erskine, Robert M; Seynnes, Olivier R; Rittweger, Jörn; Pišot, Rado; Šimunič, Boštjan; Flück, Martin

    2013-11-01

    Costameres are mechano-sensory sites of focal adhesion in the sarcolemma that provide a structural anchor for myofibrils. Their turnover is regulated by integrin-associated focal adhesion kinase (FAK). We hypothesized that changes in content of costamere components (beta 1 integrin, FAK, meta-vinculin, gamma-vinculin) with increased and reduced loading of human anti-gravity muscle would: (i) relate to changes in muscle size and molecular parameters of muscle size regulation [p70S6K, myosin heavy chain (MHC)1 and MHCIIA]; (ii) correspond to adjustments in activity and expression of FAK, and its negative regulator, FRNK; and (iii) reflect the temporal response to reduced and increased loading. Unloading induced a progressive decline in thickness of human vastus lateralis muscle after 8 and 34 days of bedrest (-4% and -14%, respectively; n = 9), contrasting the increase in muscle thickness after 10 and 27 days of resistance training (+5% and +13%; n = 6). Changes in muscle thickness were correlated with changes in cross-sectional area of type I muscle fibers (r = 0.66) and beta 1 integrin content (r = 0.76) at the mid-point of altered loading. Changes in meta-vinculin and FAK-pY397 content were correlated (r = 0.85) and differed, together with the changes of beta 1 integrin, MHCI, MHCII and p70S6K, between the mid- and end-point of resistance training. By contrast, costamere protein level changes did not differ between time points of bedrest. The findings emphasize the role of FAK-regulated costamere turnover in the load-dependent addition and removal of myofibrils, and argue for two phases of muscle remodeling with resistance training, which do not manifest at the macroscopic level. PMID:24010829

  17. Effects of gravitational unloading on activity of motoneurones of m. soleus in man

    NASA Astrophysics Data System (ADS)

    Zakirova, Albina; Shigueva, Tatiana; Tomilovskaya, Elena

    The aim of recent work was to study of participation of spinal and supraspinal structures (motor cortex) in the development of hypogravitational hyperreflexia of stretch reflexes observed under weightlessness (Kozlovskaya I.B. et. al., 1981; Reschke M.F. et al., 1984; Saenko I.V., 2007). Methods. 11 healthy volunteers took part in the research. Dry immersion (DI) with the duration of 3 and 5 days was used as onground model of weightlessness. Before and after DI thresholds and amplitudes of m. soleus H-reflex; as well as thresholds and amplitudes of m. soleus motor potentials (MEPs) evoked by magnetic stimulation of spinal roots at L5-S1 segments and cortex motor zones were defined. Results. Exposure to DI was accompanied with significant decrease of the H-reflex threshold by 23.8±8.2%, and with an increase of the relative H-reflex amplitudes by 12.89±8.3% in comparison with background. At the same time thresholds of spinal MEPs were reduced by 5% as well as and their amplitudes were increased significantly by 13.8±4.2%. The obtained data indicate an increase of motoneurones pool’s excitability of m. soleus under gravitational unloading conditions. At the same time after DI exposure a tendency to increase of thresholds of cortical MEPs was observed by 11.7±6.8% from background, and their amplitudes didn’t change in comparison with background, which gives evidence of a non-changed excitability of the motor cortex structures. In general the results of the experiments indicate the spinal nature of the hypogravitational hyperreflexia. The work was supported by RFBR projects NN 13-04-12091 Ofi-m and 11-04-01240-а.

  18. Effect of ramp configuration on easiness of handling, heart rate, and behavior of near-market weight pigs at unloading.

    PubMed

    Goumon, S; Faucitano, L; Bergeron, R; Crowe, T; Connor, M L; Gonyou, H W

    2013-08-01

    Three experiments, each using 280 pigs, were conducted in a simulated compartment to test the effect of angle of entrance (AOE) to the ramp (90°, 60°, 30°, or 0°), ramp slope (0°, 16°, 21°, or 26°), and an initial 20-cm step associated with 16° or 21° ramp slopes on the ease of handling, heart rate (HR), and behavior of near market-weight pigs during unloading. Heart rate (pigs and handler), unloading time, interventions of the handler, and reactions of the pigs were monitored. The results of the first experiment show that using a 90° AOE had detrimental effects on ease of handling (P < 0.05), HR of the pig (P < 0.05), and behavior (P < 0.05). The 0° and 30° AOE appeared to improve the ease of unloading, whereas the 60° AOE had an intermediate effect. The 30° AOE appeared to be preferable, because pigs moved at this angle balked less frequently (P < 0.01) and required less manipulation (P < 0.05) than pigs moved with a 0° AOE. The results of the second experiment show that the use of a flat ramp led to the easiest unloading, as demonstrated by the lower number of balks (P < 0.001) when pigs were moved to the ramp and less frequent use of paddle (P = 0.001) or voice (P < 0.001) on the ramp, compared with the other treatments. However, the flat ramp did not differ from the 21° ramp in many of the variables reflecting ease of handling, which may be explained by the difference in configuration between the ramps. The results also show that the use of the steepest ramp slope had the most detrimental effect on balking and backing up behavior of pigs (P < 0.001), and handling (touches, slaps, and pushes; P < 0.05 for all) when moved to the ramp and on unloading time (P < 0.01). No differences in pig HR (P < 0.05) and ease of handling on the ramp (P < 0.05) were found between a 26° and 16° ramp slope, suggesting that the length of the ramp may be one of the factors that make unloading more difficult. The results of the last experiment show that an initial

  19. Effects of Growth Hormone/IGF-I and Exercise on Unloaded Bones

    NASA Technical Reports Server (NTRS)

    Harper, J. S.; Arnaud, S. B.; Gosselink, K. L.; Grindeland, R. E.

    1994-01-01

    Growth hormone (GH) and insulin-like growth factor-I (IGF-I) in combination with exercise prevent muscle atrophy induced by unloading in the tail-suspension rat model for space flight (Gosselink et al, FASEB J 1994). This study evaluated the effects of these treatments on bone. Hypophysectomized rats were suspended (S) and treated with 1mg/kg/day CH plus IGF-I (H) or vehicle (Sal) daily by injection and exercised (Ex) by 3 climbs up a 1m ladder carrying a load equal to 30% the initial body weight (BW) 3x/day for 10 days. Tibial epiphysis (Epi) widths were measured by micrometry and femoral Bone Mineral Content (fBMC) in excised femurs by DEXA (Lunar DPX-L). Serum calcium (Ca) and phosphorus (Pi) were measured by COBAS Autoanalyzer (Roche Diag.). Ambulatory (Amb)-H treated rats showed growth rates of 6.6+-0.9 g/day, similar to S-H-Ex and higher than S-H (3.210.6, p less than 0.05) and S-Sal (-0.711.0, p less than 0.05). Epi widths were 10% lower in S-Sal, and S-Sal-Ex, and increased 100% in all H groups. fBMC was less in S than Amb, only when all S groups are compared to both Amb groups (p less than 0.03). H treatment increased fBMC (p less than 0.05) but reduced fBMC/100g BW in all H groups (p less than 0.001). The reduced density of H bone cannot be attributed to low circulating Ca. and Pi since they were higher in H than Sal (p less than 0.001). H treatment for 10 days in doses sufficient to support normal growth in BW failed to produce normal Epi widths or fBMC, even when combined with exercise. The suspension effect observed in Epi widths was not corrected by H or Ex alone, but was improved by H plus a This regimen. although effective in preventing muscle atrophy, failed to return bone measures, Epi widths and fBMC, to normal.

  20. Whole body and regional body composition changes following 10-day hypoxic confinement and unloading-inactivity.

    PubMed

    Debevec, Tadej; McDonnell, Adam C; Macdonald, Ian A; Eiken, Ola; Mekjavic, Igor B

    2014-03-01

    Future planetary habitats will expose inhabitants to both reduced gravity and hypoxia. This study investigated the effects of short-term unloading and normobaric hypoxia on whole body and regional body composition (BC). Eleven healthy, recreationally active, male participants with a mean (SD) age of 24 (2) years and body mass index of 22.4 (3.2) kg·m(-2) completed the following 3 10-day campaigns in a randomised, cross-over designed protocol: (i) hypoxic ambulatory confinement (HAMB; FIO2 = 0.147 (0.008); PIO2 = 93.8 (0.9) mm Hg), (ii) hypoxic bed rest (HBR; FIO2 = 0.147 (0.008); PIO2 = 93.8 (0.9) mm Hg), and (iii) normoxic bed rest (NBR; FIO2 = 0.209; PIO2 = 133.5 (0.7) mm Hg). Nutritional requirements were individually precalculated and the actual intake was monitored throughout the study protocol. Body mass, whole body, and regional BC were assessed before and after the campaigns using dual-energy X-ray absorptiometry. The calculated daily targeted energy intake values were 2071 (170) kcal for HBR and NBR and 2417 (200) kcal for HAMB. In both HBR and NBR campaigns the actual energy intake was within the targeted level, whereas in the HAMB the intake was lower than targeted (-8%, p < 0.05). Body mass significantly decreased in all 3 campaigns (-2.1%, -2.8%, and -2.0% for HAMB, HBR, and NBR, respectively; p < 0.05), secondary to a significant decrease in lean mass (-3.8%, -3.8%, -4.3% for HAMB, HBR, and NBR, respectively; p < 0.05) along with a slight, albeit not significant, increase in fat mass. The same trend was observed in the regional BC regardless of the region and the campaign. These results demonstrate that, hypoxia per se, does not seem to alter whole body and regional BC during short-term bed rest. PMID:24552383

  1. Five myofibrillar lesion types in eccentrically challenged, unloaded rat adductor longus muscle--a test model

    NASA Technical Reports Server (NTRS)

    Thompson, J. L.; Balog, E. M.; Fitts, R. H.; Riley, D. A.

    1999-01-01

    Sarcomere disruptions are observed in the adductor longus (AL) muscles following voluntary reloading of spaceflown and hindlimb suspension unloaded (HSU) rat, which resemble lesions in eccentrically challenged muscle. We devised and tested an eccentric contraction (ECCON) test system for the 14-day HSU rat AL. Six to 7 hours following ECCON, ALs were fixed to allow immunostaining and electron microscopy (EM). Toluidine blue-stained histology semithin sections were screened for lesion density (#/mm2). Serial semithin sections from the ECCON group were characterized for myosin immunointensity of lesions. Five myofibrillar lesion types were identified in histological semithin sections: focal contractions; wide A-bands; opaque areas; missing A-bands; and hyperstretched sarcomeres. Lesion density by type was greater for ECCON than NonECCON ALs (P< or =0.05; focal contractions and opaque regions). Lesion density (#-of-all-five-types/mm2) was significantly different (ECCON: 23.91+/-10.58 vs. NonECCON: 5.48+/-1.28, P< or =0.05; ECCON vs. SHAM: 0.00+/-0.00; P< or = 0.025). PostECCON optimal tension decreased (Poi-drop, 17.84+/-4.22%) and was correlated to lesion density (R2=0.596), but prestretch tension demonstrated the highest correlation with lesion density (R2=0.994). In lesions, the darkly staining A-band lost the normally organized thick filament alignment to differing degrees across the different lesion types. Ranking the five lesion types by a measure of lesion length deformation (hypercontracted to hyperstretched) at the light microscopy level, related to the severity of thick filament registry loss across the lesion types at the electron microscopic level. This ranking suggested that the five lesion types seen in semithin sections at the light level represented a lesion progression sequence and paralleled myosin immunostaining loss as the distorted A-band filaments spread across the hyperlengthening lesion types. Lesion ultrastructure indicated damage involved

  2. Experimental evidence of the tonic vibration reflex during whole-body vibration of the loaded and unloaded leg.

    PubMed

    Zaidell, Lisa N; Mileva, Katya N; Sumners, David P; Bowtell, Joanna L

    2013-01-01

    Increased muscle activation during whole-body vibration (WBV) is mainly ascribed to a complex spinal and supraspinal neurophysiological mechanism termed the tonic vibration reflex (TVR). However, TVR has not been experimentally demonstrated during low-frequency WBV, therefore this investigation aimed to determine the expression of TVR during WBV. Whilst seated, eight healthy males were exposed to either vertical WBV applied to the leg via the plantar-surface of the foot, or Achilles tendon vibration (ATV) at 25 Hz and 50 Hz for 70s. Ankle plantar-flexion force, tri-axial accelerations at the shank and vibration source, and surface EMG activity of m. soleus (SOL) and m. tibialis anterior (TA) were recorded from the unloaded and passively loaded leg to simulate body mass supported during standing. Plantar flexion force was similarly augmented by WBV and ATV and increased over time in a load- and frequency dependent fashion. SOL and TA EMG amplitudes increased over time in all conditions independently of vibration mode. 50 Hz WBV and ATV resulted in greater muscle activation than 25 Hz in SOL when the shank was loaded and in TA when the shank was unloaded despite the greater transmission of vertical acceleration from source to shank with 25 Hz and WBV, especially during loading. Low-amplitude WBV of the unloaded and passively loaded leg produced slow tonic muscle contraction and plantar-flexion force increase of similar magnitudes to those induced by Achilles tendon vibration at the same frequencies. This study provides the first experimental evidence supporting the TVR as a plausible mechanism underlying the neuromuscular response to whole-body vibration. PMID:24386466

  3. Phloem Unloading in Sink Leaves of Nicotiana benthamiana: Comparison of a Fluorescent Solute with a Fluorescent Virus.

    PubMed Central

    Roberts, A. G.; Cruz, S. S.; Roberts, I. M.; Prior, DAM.; Turgeon, R.; Oparka, K. J.

    1997-01-01

    Using noninvasive imaging techniques, we compared phloem unloading of the membrane-impermeant, fluorescent solute carboxyfluorescein (CF) with that of potato virus X expressing the gene for the green fluorescent protein. Although systemic virus transport took considerably longer to occur than did CF transport, unloading of both solute and virus occurred predominantly from the class III vein network, a highly branched veinal system found between class II veins. The minor veins (classes IV and V) played no role in solute or virus import but were shown to be functional in xylem transport at the time of import by labeling with Texas Red dextran. After virus exit from the class III phloem, the minor veins eventually became infected by cell-to-cell virus movement from the mesophyll. During the sink/source transition, phloem unloading of CF was inhibited from class III veins before the cessation of phloem import through them, suggesting a symplastic isolation of the phloem in class III veins before its involvement in export. The progression of the sink/source transition for carbon was unaffected by the presence of the virus in the sink leaf. However, the virus was unable to cross the sink/source boundary for carbon that was present at the time of viral entry, suggesting a limited capacity for cell-to-cell virus movement into the apical (source) region of the leaf. A functional model of the sink/source transition in Nicotiana benthamiana is presented. This model provides a framework for the analysis of solute and virus movement in leaves. PMID:12237387

  4. Mechanical Unloading of Mouse Bone in Microgravity Significantly Alters Cell Cycle Gene Set Expression

    NASA Astrophysics Data System (ADS)

    Blaber, Elizabeth; Dvorochkin, Natalya; Almeida, Eduardo; Kaplan, Warren; Burns, Brnedan

    2012-07-01

    unloading in spaceflight, we conducted genome wide microarray analysis of total RNA isolated from the mouse pelvis. Specifically, 16 week old mice were subjected to 15 days spaceflight onboard NASA's STS-131 space shuttle mission. The pelvis of the mice was dissected, the bone marrow was flushed and the bones were briefly stored in RNAlater. The pelvii were then homogenized, and RNA was isolated using TRIzol. RNA concentration and quality was measured using a Nanodrop spectrometer, and 0.8% agarose gel electrophoresis. Samples of cDNA were analyzed using an Affymetrix GeneChip\\S Gene 1.0 ST (Sense Target) Array System for Mouse and GenePattern Software. We normalized the ST gene arrays using Robust Multichip Average (RMA) normalization, which summarizes perfectly matched spots on the array through the median polish algorithm, rather than normalizing according to mismatched spots. We also used Limma for statistical analysis, using the BioConductor Limma Library by Gordon Smyth, and differential expression analysis to identify genes with significant changes in expression between the two experimental conditions. Finally we used GSEApreRanked for Gene Set Enrichment Analysis (GSEA), with Kolmogorov-Smirnov style statistics to identify groups of genes that are regulated together using the t-statistics derived from Limma. Preliminary results show that 6,603 genes expressed in pelvic bone had statistically significant alterations in spaceflight compared to ground controls. These prominently included cell cycle arrest molecules p21, and p18, cell survival molecule Crbp1, and cell cycle molecules cyclin D1, and Cdk1. Additionally, GSEA results indicated alterations in molecular targets of cyclin D1 and Cdk4, senescence pathways resulting from abnormal laminin maturation, cell-cell contacts via E-cadherin, and several pathways relating to protein translation and metabolism. In total 111 gene sets out of 2,488, about 4%, showed statistically significant set alterations. These

  5. Response of amino acids in hindlimb muscles to recovery from hypogravity and unloading by tail-cast suspension

    NASA Technical Reports Server (NTRS)

    Tischler, M. E.; Henriksen, E. J.; Jacob, S.; Cook, P. H.

    1985-01-01

    Concentrations of glutamine, glutamate, aspartate (+ asparagine) and alanine were compared in hindlimb muscles of SL-3 and ground control rats. Alanine was lower in the soleus of flown rats but not of suspended animals, with no response in other muscles except a slight increase in the unloaded plantaris. With recovery, alanine in the soleus was elevated. Since no differences in alanine metabolism were found by isolated muscle, changes in muscle alanine are probably due to altered body use of this amino acid leading to varied plasma levels.

  6. Unloading-induced slow-to-fast myosin shift in soleus muscle: nuclear MuRFs and calsarcin expression

    NASA Astrophysics Data System (ADS)

    Shenkman, Boris; Lomonosova, Yulia

    Exposure to actual and simulated microgravity is known to induce decrease in slow MyHC mRNA expression and increase in fast MyHC mRNAs expression. We supposed that altered expression of the calsarcin (CS) I and II (specific for type I and type II fibers respectively) may provide the control over myosin phenotype during unloading. We found that after 3 days of hindlimb unloading (HU) the content of CSII mRNA increased two-fold in rat soleus as compared to the cage controls. This level was maintained till the 7th day of the exposure and increased by more than 5-fold (as compared to controls) after two weeks of HU. In contrast to CSII, CSI mRNA expression didn’t change after 3 days of HU, but decreased more than 2-fold by the 7th and 14th day of HU. The increase of CSII RNA (in type II fibers) may be explained as the mechanism of stabilization of fast phenotype in all, but more important, in newly transformed type II fibers. At the same time, the decrease of CSI mRNA (in type I fibers) may be understood as counteracting the slow-to-fast transformation. Morriscot et al, (2010) demonstrated that calsarcin II expression decreased only in the double knockouts MuRF1-/MuRF2-. So, we hypothesized that CSII expression in unloaded soleus muscle might be associated with the cytoplasm-nucleus translocation of MuRF1 and MuRF2. We observed significant accumulation of MuRF1 and MuRF2 in the nuclear fraction after 3 days of HU. Thus the accumulation of MuRFs in myonuclei may promote the expression of CSII, necessary for stabilization of fast phenotype in the course of slow-to-fast shift in unloaded soleus muscle. We express our gratitude to Prof. S. Labeit (Mannheim) for kind presenting us the best antibodies against MuRF1 and MuRF2.

  7. Transcription regulation of gene expression in rat brown adipose tissue in response to unloading or 2G loading during growing period

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Hitomi, Y.; Kawano, F.; Ohira, Y.; Kizaki, T.; Nakano, N.; Sakurai, T.; Izawa, T.; Suzuki, K.; Sudoh, M.; Roy, R. R.; Ohno, H.

    2007-05-01

    The effects were investigated of long-term unloading and macrogravity on the expression of 15 genes at the mRNA levels in brown adipose tissue (BAT) from rat pups, particularly focusing on uncoupling protein (UCP) family, nitric oxide synthase (NOS) isoenzymes, and antioxidant enzymes. The animals in the unloaded group (a simulation model of spaceflight) were hindlimb-unloaded by tail suspension between postnatal day 4 and month 3, followed by 2-mo ambulation recovery. Moreover, centrifugation at 2G (an imitation of the hypergravity effects) was performed during the same period as the unloading, also followed by 2-mo ambulation recovery (adaptation to 1G from 2G). Compared with the age-matched control group, significantly lower expression levels of mRNA for UCP2, iNOS, and Cu,Zn-superoxide dismutase (Cu, Zn-SOD) in BAT were observed immediately after unloading, but not immediately after exposure to 2G. During 2-mo ambulation recovery from both extreme conditions, the expression of mRNA for Mn-SOD was enhanced, suggesting an increase in oxidative stress. These findings suggest that both micro- and macrogravity may have some influence upon the function of BAT, and that changes in the BAT function may be involved in the mechanisms subserving adaptation to such extreme conditions by what humans have to be faced with during the spaceflight and return to 1G.

  8. Systemic administration of transforming growth factor-beta 2 prevents the impaired bone formation and osteopenia induced by unloading in rats.

    PubMed Central

    Machwate, M; Zerath, E; Holy, X; Hott, M; Godet, D; Lomri, A; Marie, P J

    1995-01-01

    We investigated the effect of recombinant human transforming growth factor beta 2 (rhTGF-beta 2) administration on trabecular bone loss induced by unloading in rats. Hind limb suspension for 14 d inhibited bone formation and induced osteopenia as shown by decreased bone volume, calcium and protein contents in long bone metaphysis. Systemic infusion of rhTFG-beta 2 (2 micrograms/kg per day) maintained normal bone formation rate, and prevented the decrease in bone volume, bone mineral content, trabecular thickness and number induced by unloading. In vitro analysis of tibial marrow stromal cells showed that rhTGF-beta 2 infusion in unloaded rats increased the proliferation of osteoblast precursor cells, but did not affect alkaline phosphatase activity or osteocalcin production. Northern blot analysis of RNA extracted from the femoral metaphysis showed that rhTGF-beta 2 infusion in unloaded rats increased steady-state levels of type I collagen mRNA but not alkaline phosphatase mRNA levels. rhTGF-beta 2 infusion at the dose used had no effect on metaphyseal bone volume and formation, osteoblast proliferation or collagen expression in control rats. The results show that systemic administration of rhTGF-beta 2 enhances osteoblast precursor cell proliferation and type I collagen expression by osteoblasts, and prevents the impaired bone formation and osteopenia induced by unloading. Images PMID:7657798

  9. Regulation of unloaded cell shortening by sarcolemmal sodium-calcium exchange in isolated rat ventricular myocytes.

    PubMed Central

    Bouchard, R A; Clark, R B; Giles, W R

    1993-01-01

    1. Regulation of unloaded cell shortening and relaxation by sarcolemmal Na(+)-Ca2+ exchange was investigated in rat ventricular myocytes. Contraction of single cells at 22 +/- 1 degrees C was measured simultaneously with membrane current and voltage using the whole-cell voltage clamp technique in combination with a video edge-detection device. 2. The extent of mechanical activation (cell shortening amplitude) was strongly dependent on diastolic membrane potential over the voltage range -140 to -50 mV. This voltage sensitivity of contraction was abolished completely when a recently described inhibitory peptide of the cardiac Na(+)-Ca2+ exchanger (XIP, 2 x 10(-5) M) was present in the recording pipette, demonstrating that in rat ventricular cells Na(+)-Ca2+ exchange is modulated by diastolic membrane potential. 3. Possible influences of Na(+)-Ca2+ exchange on contraction were studied from a holding potential of -80 mV. Depolarizations (-50 to +60 mV) resulted in a bell-shaped shortening-voltage (S-V) relationship. These contractions were suppressed completely by either Cd2+ (10(-4) M) or verapamil (10(-5) M), but remained unchanged during superfusion with tetrodotoxin (TTX, 1.5 x 10(-5) M), when [NA+]o was reduced from 140 to 10 mM by substitution with either Li+ or Cs+ ions or when pipette Na+ was varied between 8 and 13 mM. XIP (2 x 10(-5) M) increased the magnitude and duration of twitch contractions, but had no effect on the shape of the S-V relationship. Thus, the Ca2+ current but not the Na+ current or Ca2+ influx due to reversed Na(+)-Ca2+ exchange can release Ca2+ from the sarcoplasmic reticulum (SR) under these experimental conditions. 4. The effect of the rate of repolarization on cell shortening was studied under voltage clamp by applying ramp waveforms immediately following the depolarizations which activated contraction. Although slowing of the rate of repolarization had no effect on the first contraction following a train of conditioning depolarizations

  10. Shuttle Discovery Being Unloaded from SCA-747 at Palmdale, California, Maintenance Facility

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Space Shuttle Discovery being unloaded from NASA's Boeing 747 Shuttle Carrier Aircraft (SCA) at Rockwell Aerospace's Palmdale facility for nine months of scheduled maintenance. Discovery and the 747 were completing a two-day flight from Kennedy Space Center, Florida, that began at 7:04 a.m. Eastern Standard Time on 27 September and included an overnight stop at Salt Lake City International Airport, Utah. At the conclusion of this mission, Discovery had flown 21 shuttle missions, totaling more than 142 days in orbit. Space Shuttles are the main element of America's Space Transportation System and are used for space research and other space applications. The shuttles are the first vehicles capable of being launched into space and returning to Earth on a routine basis. Space Shuttles are used as orbiting laboratories in which scientists and mission specialists conduct a wide variety of scientific experiments. Crews aboard shuttles place satellites in orbit, rendezvous with satellites to carry out repair missions and return them to space, and retrieve satellites and return them to Earth for refurbishment and reuse. Space Shuttles are true aerospace vehicles. They leave Earth and its atmosphere under rocket power provided by three liquid-propellant main engines with two solid-propellant boosters attached plus an external liquid-fuel tank. After their orbital missions, they streak back through the atmosphere and land like airplanes. The returning shuttles, however, land like gliders, without power and on runways. Other rockets can place heavy payloads into orbit, but, they can only be used once. Space Shuttles are designed to be continually reused. When Space Shuttles are used to transport complete scientific laboratories into space, the laboratories remain inside the payload bay throughout the mission. They are then removed after the Space Shuttle returns to Earth and can be reused on future flights. Some of these orbital laboratories, like the Spacelab, provide

  11. Investigation of Macroscopic Brittle Creep Failure Caused by Microcrack Growth Under Step Loading and Unloading in Rocks

    NASA Astrophysics Data System (ADS)

    Li, Xiaozhao; Shao, Zhushan

    2016-07-01

    The growth of subcritical cracks plays an important role in the creep of brittle rock. The stress path has a great influence on creep properties. A micromechanics-based model is presented to study the effect of the stress path on creep properties. The microcrack model of Ashby and Sammis, Charles' Law, and a new micro-macro relation are employed in our model. This new micro-macro relation is proposed by using the correlation between the micromechanical and macroscopic definition of damage. A stress path function is also introduced by the relationship between stress and time. Theoretical expressions of the stress-strain relationship and creep behavior are derived. The effects of confining pressure on the stress-strain relationship are studied. Crack initiation stress and peak stress are achieved under different confining pressures. The applied constant stress that could cause creep behavior is predicted. Creep properties are studied under the step loading of axial stress or the unloading of confining pressure. Rationality of the micromechanics-based model is verified by the experimental results of Jinping marble. Furthermore, the effects of model parameters and the unloading rate of confining pressure on creep behavior are analyzed. The coupling effect of step axial stress and confining pressure on creep failure is also discussed. The results provide implications on the deformation behavior and time-delayed rockburst mechanism caused by microcrack growth on surrounding rocks during deep underground excavations.

  12. Autonomic Heart Rate Control at Rest and During Unloading of the Right Ventricle in Repaired Tetralogy of Fallot in Adolescents

    PubMed Central

    Wyller, Vegard Bruun; Saul, J. Philip; Barbieri, Riccardo; de Lange, Charlotte; Hopp, Einar; Norum, Ingvild B.; Thaulow, Erik

    2008-01-01

    Arrhythmias in patients with repaired tetralogy of Fallot (ToF) might be due in part to altered autonomic heart rate (HR) control caused by altered right ventricle hemodynamics. This study investigated autonomic HR control in ToF adolescents at rest and during unloading of the right ventricle. A total of 17 ToF patients and 56 healthy controls aged 12 to 18 years underwent orthostatic stress with lower body negative pressure (LBNP) of −20 mm Hg. HR, blood pressure and stroke volume were recorded non-invasively. Indices of HR variability were computed in time and frequency domains. All ToF patients also underwent cardiac magnetic resonance imaging, demonstrating pulmonary regurgitation and right ventricular dilation. At rest, HR variability indices of vagal heart rate control were non-significantly lower in the ToF patients compared to controls. During LBNP, HR increased more in controls than ToF patients (p ≤ 0.001). Further, most HR variability indices decreased among controls, but increased among ToF patients (p ≤ 0.01 or p ≤ 0.001 for all variables), suggesting vagal activation in the ToF patients. In conclusion, adolescents after ToF repair have fairly normal HR control at rest despite altered right ventricular hemodynamics. During unloading of the right ventricle, however, vagal HR control increases in the ToF patients and decreases in the controls. PMID:18929714

  13. The Enok acetyltransferase complex interacts with Elg1 and negatively regulates PCNA unloading to promote the G1/S transition.

    PubMed

    Huang, Fu; Saraf, Anita; Florens, Laurence; Kusch, Thomas; Swanson, Selene K; Szerszen, Leanne T; Li, Ge; Dutta, Arnob; Washburn, Michael P; Abmayr, Susan M; Workman, Jerry L

    2016-05-15

    KAT6 histone acetyltransferases (HATs) are highly conserved in eukaryotes and are involved in cell cycle regulation. However, information regarding their roles in regulating cell cycle progression is limited. Here, we report the identification of subunits of the Drosophila Enok complex and demonstrate that all subunits are important for its HAT activity. We further report a novel interaction between the Enok complex and the Elg1 proliferating cell nuclear antigen (PCNA)-unloader complex. Depletion of Enok in S2 cells resulted in a G1/S cell cycle block, and this block can be partially relieved by depleting Elg1. Furthermore, depletion of Enok reduced the chromatin-bound levels of PCNA in both S2 cells and early embryos, suggesting that the Enok complex may interact with the Elg1 complex and down-regulate its PCNA-unloading function to promote the G1/S transition. Supporting this hypothesis, depletion of Enok also partially rescued the endoreplication defects in Elg1-depleted nurse cells. Taken together, our study provides novel insights into the roles of KAT6 HATs in cell cycle regulation through modulating PCNA levels on chromatin. PMID:27198229

  14. Fiber-type susceptibility to eccentric contraction-induced damage of hindlimb-unloaded rat AL muscles

    NASA Technical Reports Server (NTRS)

    Vijayan, K.; Thompson, J. L.; Norenberg, K. M.; Fitts, R. H.; Riley, D. A.

    2001-01-01

    Slow oxidative (SO) fibers of the adductor longus (AL) were predominantly damaged during voluntary reloading of hindlimb unloaded (HU) rats and appeared explainable by preferential SO fiber recruitment. The present study assessed damage after eliminating the variable of voluntary recruitment by tetanically activating all fibers in situ through the motor nerve while applying eccentric (lengthening) or isometric contractions. Muscles were aldehyde fixed and resin embedded, and semithin sections were cut. Sarcomere lesions were quantified in toluidine blue-stained sections. Fibers were typed in serial sections immunostained with antifast myosin and antitotal myosin (which highlights slow fibers). Both isometric and eccentric paradigms caused fatigue. Lesions occurred only in eccentrically contracted control and HU muscles. Fatigue did not cause lesions. HU increased damage because lesioned- fiber percentages within fiber types and lesion sizes were greater than control. Fast oxidative glycolytic (FOG) fibers were predominantly damaged. In no case did damaged SO fibers predominate. Thus, when FOG, SO, and hybrid fibers are actively lengthened in chronically unloaded muscle, FOG fibers are intrinsically more susceptible to damage than SO fibers. Damaged hybrid-fiber proportions ranged between these extremes.

  15. Comparison of hindlimb unloading and partial weight suspension models for spaceflight-type condition induced effects on white blood cells

    NASA Astrophysics Data System (ADS)

    Wilson, Jolaine M.; Krigsfeld, Gabriel S.; Sanzari, Jenine K.; Wagner, Erika B.; Mick, Rosemarie; Kennedy, Ann R.

    2012-01-01

    Animal models are frequently used to assist in the determination of the long- and short-term effects of space flight. The space environment, including microgravity, can impact many physiological and immunological system parameters. It has been found that ground based models of microgravity produce changes in white blood cell counts, which negatively affects immunologic function. As part of the Center of Acute Radiation Research (CARR), we compared the acute effects on white blood cell parameters induced by the more traditionally used animal model of hindlimb unloading (HU) with a recently developed reduced weightbearing analog known as partial weight suspension (PWS). Female ICR mice were either hindlimb unloaded or placed in the PWS system at 16% quadrupedal weightbearing for 4 h, 1, 2, 7 or 10 days, at which point complete blood counts were obtained. Control animals (jacketed and non-jacketed) were exposed to identical conditions without reduced weightbearing. Results indicate that significant changes in total white blood cell (WBC), neutrophil, lymphocyte, monocyte and eosinophil counts were observed within the first 2 days of exposure to each system. These differences in blood cell counts normalized by day 7 in both systems. The results of these studies indicate that there are some statistically significant changes observed in the blood cell counts for animals exposed to both the PWS and HU simulated microgravity systems.

  16. [Changes in cell respiration of postural muscle fibers under long-term gravitational unloading after dietary succinate supplementation].

    PubMed

    Ogneva, I V; Veselova, O M; Larina, I M

    2011-01-01

    The intensity of cell respiration of the rat m. soleus, m. gastrocnemius c.m. and tibialis anterior fibers during 35-day gravitational unloading, with the addition of succinate in the diet at a dosage rate of 50 mg per 1 kg animal weight has been investigated. The gravitational unloading was modeled by antiorthostatic hindlimb suspension. The intensity of cell respiration was estimated by polarography. It was shown that the rate of oxygen consumption by soleus and gastrocnemius fibers on endogenous and exogenous substrates and with the addition of ADP decreases after the discharge. This may be associated with the transition to the glycolytic energy path due to a decrease in the EMG-activity. At the same time, the respiration rate after the addition of exogenous substrates in soleus fibers did not increase, indicating a disturbance in the function of the NCCR-section of the respiratory chain and more pronounced changes in the structure of muscle fibers. In tibialis anterior fibers, no changes in oxygen consumption velocity were observed. The introduction of succinate to the diet of rats makes it possible to prevent the negative effects of hypokinesia, although it reduces the basal level of intensity of cell respiration. PMID:21442893

  17. Sucrose transport and phloem unloading in peach fruit: potential role of two transporters localized in different cell types.

    PubMed

    Zanon, Laura; Falchi, Rachele; Santi, Simonetta; Vizzotto, Giannina

    2015-06-01

    Several complex physiological processes, which include long-distance translocation in the phloem and unloading in sink tissues, govern the partitioning of sugars in economically important organs, such as peach fruit. In this study, we took advantage of a symplastic tracer, carboxyfluorescein (CF), providing evidence for an apoplastic sucrose transfer in the early (SI) and middle (SIII) phases of peach fruit development. Moreover, using a combination of in situ hybridization and laser microdissection-assisted expression analysis, three putative sucrose transporters encoding genes (PpSUT1, PpSUT2, PpSUT4) were transcriptionally analyzed to relate their expression with sucrose storage in this organ. Our study revealed that PpSUT2 and PpSUT4 are the genes predominantly expressed in fruit flesh, and the detailed analysis of their expression pattern in the different cell types enabled us to suggest a specialized role in sucrose distribution. Both PpSUTs transporters could be involved in the retrieval of sucrose lost from the symplastic continuum of the phloem and, when expressed in parenchyma cells, they could be active in the import of sucrose into sink tissues, via symport from the apoplast. An alternative hypothesis has been proposed and discussed for PpSUT4 because of its putative tonoplastic localization. Taken together, our results provide new insights into the molecular mechanisms underpinning sucrose unloading and accumulation in peach fruit. PMID:25348206

  18. Influence of anthropogenic groundwater unloading in Indo-Gangetic plains on the 25 April 2015 Mw 7.8 Gorkha, Nepal earthquake

    NASA Astrophysics Data System (ADS)

    Kundu, Bhaskar; Vissa, Naresh Krishna; Gahalaut, V. K.

    2015-12-01

    Groundwater usage in the Indo-Gangetic plains exceeds replenishment of aquifers, leading to substantial reduction in the mass. Such anthropogenic crustal unloading may promote long-term fault slip or may modulate seismic activity in the adjoining Himalayan region. Our simulation using Gravity Recovery and Climate Experiment data and hydrological models of such a process indicates that the thrust earthquakes on the Main Himalayan Thrust (MHT), including the recent 25 April 2015 Mw 7.8 Gorkha, Nepal earthquake, are probably influenced by the anthropogenic groundwater unloading process in the Gangetic plains. The groundwater withdrawal leading to crustal unloading in the Gangetic plains causes a significant component of horizontal compression which adds to the secular interseimic compression at the seismogenic depth (5-20 km) on the MHT beneath the Himalayan arc and at hypocentral depth of the 2015 Gorkha, Nepal earthquake. This effect enhances the Coulomb stress on the locked zone of MHT.

  19. Time/motion observations and dose analysis of reactor loading, transportation, and dry unloading of an overweight truck spent fuel shipment

    SciTech Connect

    Hostick, C.J.; Lavender, J.C.; Wakeman, B.H.

    1992-04-01

    This document presents observed activity durations and radiation dose analyses for an overweight truck shipment of pressurized water reactor (PWR) spent fuel from the Surry Power Station in Virginia to the Idaho National Engineering Laboratory. The shipment consisted of a TN-8L shipping cask carrying three 9-year-old PWR spent fuel assemblies. Handling times and dose analyses for at-reactor activities were completed by Virginia Electric and Power Company (Virginia Power) personnel. Observations of in-transit and unloading activities were made by Pacific Northwest Laboratory (PNL) personnel, who followed the shipment for approximately 2800 miles and observed cask unloading activities. In-transit dose estimates were calculated using dose rate maps provided by Virginia Power for a fully loaded TN-8L shipping cask. The dose analysis for the cask unloading operations is based on the observations of PNL personnel.

  20. [Electrogenic activity of Na-K-ATPase and calcium ions in m. soleus fibers of rats and Mongolian gerbil during simulation of gravitational unloading].

    PubMed

    Kravtsova, V V; Ogneva, I V; Altaeva, E G; Razgovorova, I A; Tiapkina, O V; Nikol'skiĭ, E E; Shenkman, B S; Krivoĭ, I I

    2010-01-01

    Some of the electrophysiological parameters of m. soleus of rat and Mongolian gerbil, and Ca ions content in fiber myoplasm were compared in different periods of gravitational unloading simulated by tail-suspension. No difference was found between the control animals as for membrane potential at rest, electrogenic activities of Na-K-ATPase and its isoforms, and input resistance of m. soleus fibers. At the same time, unlike rats, gerbils exhibited a substantial Ca decrease in myoplasm. From day one to 14 of gravitational unloading the pace of electrophysiological changes in gerbil's m. soleus was noticeably slower than of rat's, whereas Ca ions depositing in myoplasm was observed in both species already at the beginning ofsuspension. Analysis of the results suggests that adaptive changes in m. soleus of Mongolian gerbil and rat during simulated gravitational unloading are fundamentally different due to, probably, peculiar water-electrolyte metabolism, type of locomotion, and other factors which are still unclear. PMID:20799658

  1. Therapeutic approaches for muscle wasting disorders.

    PubMed

    Lynch, Gordon S; Schertzer, Jonathan D; Ryall, James G

    2007-03-01

    Muscle wasting and weakness are common in many disease states and conditions including aging, cancer cachexia, sepsis, denervation, disuse, inactivity, burns, HIV-acquired immunodeficiency syndrome (AIDS), chronic kidney or heart failure, unloading/microgravity, and muscular dystrophies. Although the maintenance of muscle mass is generally regarded as a simple balance between protein synthesis and protein degradation, these mechanisms are not strictly independent, but in fact they are coordinated by a number of different and sometimes complementary signaling pathways. Clearer details are now emerging about these different molecular pathways and the extent to which these pathways contribute to the etiology of various muscle wasting disorders. Therapeutic strategies for attenuating muscle wasting and improving muscle function vary in efficacy. Exercise and nutritional interventions have merit for slowing the rate of muscle atrophy in some muscle wasting conditions, but in most cases they cannot halt or reverse the wasting process. Hormonal and/or other drug strategies that can target key steps in the molecular pathways that regulate protein synthesis and protein degradation are needed. This review describes the signaling pathways that maintain muscle mass and provides an overview of some of the major conditions where muscle wasting and weakness are indicated. The review provides details on some therapeutic strategies that could potentially attenuate muscle atrophy, promote muscle growth, and ultimately improve muscle function. The emphasis is on therapies that can increase muscle mass and improve functional outcomes that will ultimately lead to improvement in the quality of life for affected patients. PMID:17258813

  2. A New Animal Model for Investigation of Mechanical Unloading in Hypertrophic and Failing Hearts: Combination of Transverse Aortic Constriction and Heterotopic Heart Transplantation

    PubMed Central

    Stenzig, Justus; Biermann, Daniel; Jelinek, Marisa; Reichenspurner, Hermann; Eschenhagen, Thomas; Ehmke, Heimo; Schwoerer, Alexander P.

    2016-01-01

    Objectives Previous small animal models for simulation of mechanical unloading are solely performed in healthy or infarcted hearts, not representing the pathophysiology of hypertrophic and dilated hearts emerging in heart failure patients. In this article, we present a new and economic small animal model to investigate mechanical unloading in hypertrophic and failing hearts: the combination of transverse aortic constriction (TAC) and heterotopic heart transplantation (hHTx) in rats. Methods To induce cardiac hypertrophy and failure in rat hearts, three-week old rats underwent TAC procedure. Three and six weeks after TAC, hHTx with hypertrophic and failing hearts in Lewis rats was performed to induce mechanical unloading. After 14 days of mechanical unloading animals were euthanatized and grafts were explanted for further investigations. Results 50 TAC procedures were performed with a survival of 92% (46/50). When compared to healthy rats left ventricular surface decreased to 5.8±1.0 mm² (vs. 9.6± 2.4 mm²) (p = 0.001) after three weeks with a fractional shortening (FS) of 23.7± 4.3% vs. 28.2± 1.5% (p = 0.01). Six weeks later, systolic function decreased to 17.1± 3.2% vs. 28.2± 1.5% (p = 0.0001) and left ventricular inner surface increased to 19.9±1.1 mm² (p = 0.0001). Intraoperative graft survival during hHTx was 80% with 46 performed procedures (37/46). All transplanted organs survived two weeks of mechanical unloading. Discussion Combination of TAC and hHTx in rats offers an economic and reproducible small animal model enabling serial examination of mechanical unloading in a truly hypertrophic and failing heart, representing the typical pressure overloaded and dilated LV, occurring in patients with moderate to severe heart failure. PMID:26841021

  3. Stimulating angiogenesis mitigates the unloading-induced reduction in osteogenesis in early-stage bone repair in rats

    PubMed Central

    Matsumoto, Takeshi; Sato, Shota

    2015-01-01

    Accelerating fracture healing during bed rest allows early mobilization and avoids prolonged fracture healing times. We tested the hypothesis that stimulating angiogenesis with deferoxamine (DFO) mitigates the unloading-induced reduction in early-stage bone repair. Rats aged 12 weeks were subjected to cortical drilling on their tibial diaphysis under anesthesia and treated with hindlimb unloading (HU), HU and DFO administration (DFOHU), or weight bearing (WB) for 5 or 10 days (HU5/10, DFOHU5/10, WB5/10; n = 8 per groups) until sacrifice for vascular casting with a zirconium dioxide-based contrast agent. Taking advantage of its absorption discontinuity at the K-absorption edge, vascular and bone images in the drill-hole defects were acquired by synchrotron radiation subtraction CT. Bone repair was reduced in HU rats. The bone volume fraction (B.Vf) was 88% smaller in HU5 and 42% smaller in HU10 than in WB5/10. The bone segment densities (B.Seg) were 97% smaller in HU5 and 141% larger in HU10 than in WB5/10, and bone thickness (B.Th) was 38% smaller in HU10 than in WB10. The vascular volume fraction (V.Vf) was 35% and the mean vessel diameter (V.D) was 13% smaller in HU10 than in WB10. When compared according to categorized vessel sizes, V.Vf in the diameter ranges 20–30, 30–40, and >40 μm were smaller in HU10 than in WB10, and V.Seg in the diameter range >40 μm was smaller in HU10 than in WB10. In contrast, there was no difference in B.Vf between DFOHU5/10 and WB5/10 and in V.Vf between DFOHU10 and WB10, though B.Seg remained 86% smaller in DFOHU5 and 94% larger in DFOHU10 than in WB5/10, and B.Th and V.D were 23% and 14% lower in DFOHU10 than in WB10. Vessel size-specific V.Vf in the diameter ranges 10–20 and 20–30 μm was larger in DFOHU5 than in HU5. In conclusion, the enhanced angiogenic ingrowth mitigates the reduction in bone repair during mechanical unloading. PMID:25780087

  4. Waste Isolation Pilot Plant Title I operator dose calculations. Final report, LATA report No. 90

    SciTech Connect

    Hughes, P.S.; Rigdon, L.D.

    1980-02-01

    The radiation exposure dose was estimated for the Waste Isolation Pilot Plant (WIPP) operating personnel who do the unloading and transporting of the transuranic contact-handled waste. Estimates of the radiation source terms for typical TRU contact-handled waste were based on known composition and properties of the waste. The operations sequence for waste movement and storage in the repository was based upon the WIPP Title I data package. Previous calculations had been based on Conceptual Design Report data. A time and motion sequence was developed for personnel performing the waste handling operations both above and below ground. Radiation exposure calculations were then performed in several fixed geometries and folded with the time and motion studies for individual workers in order to determine worker exposure on an annual basis.

  5. Energy Absorption in a Load-Unload Cycle of Knee Implant Using Fractal Model of Rough Surfaces

    NASA Astrophysics Data System (ADS)

    Hodaei, Mohammad; Farhang, Kambiz

    2016-05-01

    Roughness measurement of knee implant surfaces is investigated. The study of roughness measurement show that the topography of knee implant surface is multi-scale and surface spectra follows a power law behavior. A magnification of rough surface topography implies that there is no difference between original and magnified profile of implant surface. For implant surface, statistical parameters such as variance of height, curvature, and slope are found to be scale-dependent. Fractal representation of implant surface shows that the size-distribution of the multi-scale contacts spots follows a power law and is characterized by the fractal dimension of implant surface. Fractal surface description of the rough surfaces of knee implant is used to obtain force-displacement relationship of the contact force. Using an approximate function through the fusion of two piecewise functions, energy absorption of a knee implant in a single cycle of load-unload is obtained.

  6. PGC-1α is important for maintaining the balance of muscle mass and myofiber types in unloaded muscle atrophy

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoping; He, Jian; Wang, Fei; Zhang, Peng; Liu, Hongju; Li, Wenjiong

    2016-07-01

    PGC-1α, a transcriptional co-activator, has been shown mainly to determine the development of oxidative myofibers in skeletal muscle. However, whether PGC-1α functions to regulate the unloaded muscle atrophy and composition of myofiber types keeps unclear. MCK-PGC-1α overexpression transgenic mice (TG) and its wild type littermates (WT) were subjected to hindlimb unloading (HU) and induced unloaded muscle atrophy. After 14 days of HU, the mass of gastrocnemius, soleus, and plantaris muscles in WT mice decreased 17.9%, 28.2%, and 14.8%, respectively (P<0.01), compared with ground weight-bearing control muscles. PGC-1α transgenic mice showed a 14.0% (P<0.05), 20.4% (P<0.01), 11.8% decrease in gastrocnemius, soleus, and plantaris muscles mass after HU. To further confirm the effect of PGC-1α over-expression on the muscle mass loss under HU, change rate of muscle-body weight ratio was calculated, and the results indicated that the reduction of change rate of muscle-body weight ratio in PGC-1α transgenic gastrocnemius and soleus was significantly less than in WT mice (P<0.01). Moreover, in TG mice compared to WT mice there were significantly less reduction rate of slow-twitch myofiber MHC-I and MHC-IIa (MHC-I, -3.0±0.2% vs -14.9±4.2%, p<0.01, MHC-IIa, -3.5±2.7% vs -6.2±3.7%, p<0.01 ), while there was significantly less induction rate of fast-twitch myofiber MHC-IIb (MHC-IIb, +0.6±0.6% vs +3.7±2.9%, p<0.01 ). The real-time PCR and Western blot analysis confirmed that PGC-1α overexpression mice markedly rescued the muscle atrophy and myofiber switching from oxidative to glycolytic associated with a decrease in pSmad3 level after 14 days of HU. Importantly, overexpression of PGC-1α in C2C12 myoblasts protected PGC-1α-transfected myotubes from atrophy in vitro and the effect could be partially blocked by inducing pSmad3 with constitutively activated Smad3(C.A. smad3) transfection. Therefore, this study demonstrated a novel role and mechanism for PGC-1α in

  7. The use of satellites in non-goestationary orbits for unloading geostationary communication satellite traffic peaks. Volume 2: Technical report

    NASA Technical Reports Server (NTRS)

    Price, K.; Turner, A.; Nguyen, T.; Doong, W.; Weyandt, C.

    1987-01-01

    The part of the geostationary (GEO) orbital arc used for United States domestic fixed, communications service is rapidly becoming filled with satellites. One of the factors currently limiting its utilization is that communications satellites must be designed to have sufficient capacity to handle peak traffic leads, and thus are under utilized most of the time. A solution is to use satellites in suitable non-geostationary orbits to unload the traffic peaks. Three different designs for a non-geostationary orbit communications satellite system are presented for the 1995 time frame. The economic performance is analyzed and compared with geostationary satellites for two classes of service, trunking and customer premise service. The result is that the larger payload of the non-geostationary satellite offsets the burdens of increased complexity and worse radiation environment to give improved economic performance. Depending on ground terminal configuration, the improved economic performance of the space segment may be offset by increased ground terminal expenses.

  8. Hazardous Waste

    MedlinePlus

    ... you throw these substances away, they become hazardous waste. Some hazardous wastes come from products in our homes. Our garbage can include such hazardous wastes as old batteries, bug spray cans and paint ...

  9. Effect of branched-chain amino acid supplementation during unloading on regulatory components of protein synthesis in atrophied soleus muscles.

    PubMed

    Bajotto, Gustavo; Sato, Yuzo; Kitaura, Yasuyuki; Shimomura, Yoshiharu

    2011-08-01

    Maintenance of skeletal muscle mass depends on the equilibrium between protein synthesis and protein breakdown; diminished functional demand during unloading breaks this balance and leads to muscle atrophy. The current study analyzed time-course alterations in regulatory genes and proteins in the unloaded soleus muscle and the effects of branched-chain amino acid (BCAA) supplementation on muscle atrophy and abundance of molecules that regulate protein turnover. Short-term (6 days) hindlimb suspension of rats resulted in significant losses of myofibrillar proteins, total RNA, and rRNAs and pronounced atrophy of the soleus muscle. Muscle disuse induced upregulation and increases in the abundance of the eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), increases in gene and protein amounts of two ubiquitin ligases (muscle RING-finger protein 1 and muscle atrophy F-box protein), and decreases in the expression of cyclin D1, the ribosomal protein S6 kinase 1, the mammalian target of rapamycin (mTOR), and ERK1/2. BCAA addition to the diet did not prevent muscle atrophy and had no apparent effect on regulators of proteasomal protein degradation. However, BCAA supplementation reduced the loss of myofibrillar proteins and RNA, attenuated the increases in 4E-BP1, and partially preserved cyclin D1, mTOR and ERK1 proteins. These results indicate that BCAA supplementation alone does not oppose protein degradation but partly preserves specific signal transduction proteins that act as regulators of protein synthesis and cell growth in the non-weight-bearing soleus muscle. PMID:21222129

  10. Differential impact of mechanical unloading on structural and nonstructural components of the extracellular matrix in advanced human heart failure.

    PubMed

    Sakamuri, Siva S V P; Takawale, Abhijit; Basu, Ratnadeep; Fedak, Paul W M; Freed, Darren; Sergi, Consolato; Oudit, Gavin Y; Kassiri, Zamaneh

    2016-06-01

    Adverse remodeling of the extracellular matrix (ECM) is a significant characteristic of heart failure. Reverse remodeling of the fibrillar ECM secondary to mechanical unloading of the left ventricle (LV) by left ventricular assist device (LVAD) has been subject of intense investigation; however, little is known about the impacts on nonfibrillar ECM and matricellular proteins that also contribute to disease progression. Explanted failing hearts were procured from patients with nonischemic dilated cardiomyopathy (DCM) with or without LVAD support, and compared to nonfailing control hearts. LV free wall specimens were formalin-fixed, flash-frozen or optimum cutting temperature-mount frozen. Histologic and biochemical assessment of fibrillar ECM showed that LVAD support was associated with lower levels of insoluble collagen, collagen type I mRNA, and collagen I/III ratio compared with no-LVAD hearts. A disintegrin and Metalloproteinase with Thrombospondin Motifs-2 (ADAM-TS2), a procollagen endopeptidase, was reduced in no-LVAD but not in LVAD hearts. The rise in ECM proteolytic activities was significantly lower in LVAD hearts. Matrix metalloproteinases (MMP1, MMP2, MMP8, MMP13, and MT1-MMP/MMP14) were comparable between DCM hearts. Tissue inhibitor of metalloproteinase (TIMP)3 and TIMP4 messenger RNA and protein showed the greatest reduction in no-LVAD hearts. Basement membrane proteins exhibited less severe disarray of laminin and fibronectin-1 in LVAD-supported hearts. The rise in matricellular protein, osteopontin, was suppressed in LVAD hearts, whereas secreted protein, acidic, cysteine-rich (SPARC) levels was unaffected by LVAD. Mechanical unloading of the failing DCM hearts can restore the fibrillar ECM and the basement membrane, contributing toward improved clinical outcomes. However, persistent elevation of matricellular proteins such as SPARC could contribute to the relapse of failing hearts on removal of LVAD support. PMID:26963743

  11. The influence of acute unloading on left ventricular strain and strain rate by speckle tracking echocardiography in a porcine model.

    PubMed

    Dahle, Geir Olav; Stangeland, Lodve; Moen, Christian Arvei; Salminen, Pirjo-Riitta; Haaverstad, Rune; Matre, Knut; Grong, Ketil

    2016-05-15

    Noninvasive measurements of myocardial strain and strain rate by speckle tracking echocardiography correlate to cardiac contractile state but also to load, which may weaken their value as indices of inotropy. In a porcine model, we investigated the influence of acute dynamic preload reductions on left ventricular strain and strain rate and their relation to the pressure-conductance catheter-derived preload recruitable stroke work (PRSW) and peak positive first derivative of left ventricular pressure (LV-dP/dtmax). Speckle tracking strain and strain rate in the longitudinal, circumferential, and radial directions were measured during acute dynamic reductions of end-diastolic volume during three different myocardial inotropic states. Both strain and strain rate were sensitive to unloading of the left ventricle (P < 0.001), but the load dependency for strain rate was modest compared with strain. Changes in longitudinal and circumferential strain correlated more strongly to changes in end-diastolic volume (r = -0.86 and r = -0.72) than did radial strain (r = 0.35). Longitudinal, circumferential, and radial strain significantly correlated with LV-dP/dtmax (r = -0.53, r = -0.46, and r = 0.86), whereas only radial strain correlated with PRSW (r = 0.55). Strain rate in the longitudinal, circumferential and radial direction significantly correlated with both PRSW (r = -0.64, r = -0.58, and r = 0.74) and LV-dP/dtmax (r = -0.95, r = -0.70, and r = 0.85). In conclusion, the speckle tracking echocardiography-derived strain rate is more robust to dynamic ventricular unloading than strain. Longitudinal and circumferential strain could not predict load-independent contractility. Strain rates, and especially in the radial direction, are good predictors of preload-independent inotropic markers derived from conductance catheter. PMID:26968547

  12. Brassinosteroids are involved in controlling sugar unloading in Vitis vinifera 'Cabernet Sauvignon' berries during véraison.

    PubMed

    Xu, Fan; Xi, Zhu-Mei; Zhang, Hui; Zhang, Cheng-Jun; Zhang, Zhen-Wen

    2015-09-01

    Sugar unloading in grape berries is a crucial step in the long-distance transport of carbohydrates from grapevine leaves to berries. Brassinosteroids (BRs) mediate many physiological processes in plants including carbohydrate metabolism. Here, 'Cabernet Sauvignon' (Vitis vinifera L.) grape berries cultivated in clay loam fields were treated with an exogenous BR (24-epibrassinolide; EBR), a BR synthesis inhibitor (brassinazole; Brz), Brz + EBR (sprayed with EBR 24 h after a Brz treatment), and deionized water (control) at the onset of véraison. The EBR treatment sharply increased the soluble sugars content in the berries, but decreased it in the skins. The EBR and Brz + EBR treatments significantly promoted the activities of both invertases (acidic and neutral) and sucrose synthase (sucrolytic) at various stages of ripening. The mRNA levels of genes encoding sucrose metabolic invertase (VvcwINV), and monosaccharide (VvHT3, 4, 5 and 6) and disaccharide (VvSUC12 and 27) transporters were increased by the EBR and/or Brz + EBR treatments. Generally, the effects of the Brz treatment on the measured targets contrasted with the effects of the EBR treatments. The EBR and Brz treatments inhibited the biosynthesis of the endogenous BRs 6-deoxocastastarone and castasterone. Both EBR and Brz + EBR treatments increased the brassinolide contents, down-regulated the expression of genes encoding BRs biosynthetic enzymes BRASSINOSTEROID-6-OXIDASE and DWARF1, (VvBR6OX1 and VvDWF1) and induced BR receptor gene BRASSINOSTEROID INSENSITIVE 1 (VvBRI1) expression in deseeded berries. Together, these results show that BRs are involved in controlling sugar unloading in grape berries during véraison. PMID:26113159

  13. Predicting Bone Mechanical State During Recovery After Long-Duration Skeletal Unloading Using QCT and Finite Element Modeling

    NASA Technical Reports Server (NTRS)

    Chang, Katarina L.; Pennline, James A.

    2013-01-01

    During long-duration missions at the International Space Station, astronauts experience weightlessness leading to skeletal unloading. Unloading causes a lack of a mechanical stimulus that triggers bone cellular units to remove mass from the skeleton. A mathematical system of the cellular dynamics predicts theoretical changes to volume fractions and ash fraction in response to temporal variations in skeletal loading. No current model uses image technology to gather information about a skeletal site s initial properties to calculate bone remodeling changes and then to compare predicted bone strengths with the initial strength. The goal of this study is to use quantitative computed tomography (QCT) in conjunction with a computational model of the bone remodeling process to establish initial bone properties to predict changes in bone mechanics during bone loss and recovery with finite element (FE) modeling. Input parameters for the remodeling model include bone volume fraction and ash fraction, which are both computed from the QCT images. A non-destructive approach to measure ash fraction is also derived. Voxel-based finite element models (FEM) created from QCTs provide initial evaluation of bone strength. Bone volume fraction and ash fraction outputs from the computational model predict changes to the elastic modulus of bone via a two-parameter equation. The modulus captures the effect of bone remodeling and functions as the key to evaluate of changes in strength. Application of this time-dependent modulus to FEMs and composite beam theory enables an assessment of bone mechanics during recovery. Prediction of bone strength is not only important for astronauts, but is also pertinent to millions of patients with osteoporosis and low bone density.

  14. 46 CFR 35.35-42 - Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB/ALL. 35.35-42 Section 35.35-42 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Cargo Handling § 35.35-42 Restrictions on...

  15. 46 CFR 35.35-42 - Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB/ALL. 35.35-42 Section 35.35-42 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Cargo Handling § 35.35-42 Restrictions on...

  16. 46 CFR 35.35-42 - Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB/ALL. 35.35-42 Section 35.35-42 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Cargo Handling § 35.35-42 Restrictions on...

  17. 46 CFR 35.35-42 - Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB/ALL. 35.35-42 Section 35.35-42 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Cargo Handling § 35.35-42 Restrictions on...

  18. 46 CFR 153.1119 - When to prewash and discharge NLS residues from a prewash; unloading an NLS cargo in a country...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... prewash; unloading an NLS cargo in a country whose Administration is not signatory to MARPOL 73/78... country whose Administration is not signatory to MARPOL 73/78: Categories A, B, and C. (a) Except as... Administration is signatory to MARPOL 73/78, a written attestation from the person in charge of each prewash...

  19. Curcumin counteracts loss of force and atrophy of hindlimb unloaded rat soleus by hampering neuronal nitric oxide synthase untethering from sarcolemma

    PubMed Central

    Vitadello, Maurizio; Germinario, Elena; Ravara, Barbara; Libera, Luciano Dalla; Danieli-Betto, Daniela; Gorza, Luisa

    2014-01-01

    Antioxidant administration aimed to antagonize the development and progression of disuse muscle atrophy provided controversial results. Here we investigated the effects of curcumin, a vegetal polyphenol with pleiotropic biological activity, because of its ability to upregulate glucose-regulated protein 94 kDa (Grp94) expression in myogenic cells. Grp94 is a sarco-endoplasmic reticulum chaperone, the levels of which decrease significantly in unloaded muscle. Rats were injected intraperitoneally with curcumin and soleus muscle was analysed after 7 days of hindlimb unloading or standard caging. Curcumin administration increased Grp94 protein levels about twofold in muscles of ambulatory rats (P < 0.05) and antagonized its decrease in unloaded ones. Treatment countered loss of soleus mass and myofibre cross-sectional area by approximately 30% (P ≤ 0.02) and maintained a force–frequency relationship closer to ambulatory levels. Indexes of muscle protein and lipid oxidation, such as protein carbonylation, revealed by Oxyblot, and malondialdehyde, measured with HPLC, were significantly blunted in unloaded treated rats compared to untreated ones (P = 0.01). Mechanistic involvement of Grp94 was suggested by the disruption of curcumin-induced attenuation of myofibre atrophy after transfection with antisense grp94 cDNA and by the drug-positive effect on the maintenance of the subsarcolemmal localization of active neuronal nitric oxide synthase molecules, which were displaced to the sarcoplasm by unloading. The absence of additive effects after combined administration of a neuronal nitric oxide synthase inhibitor further supported curcumin interference with this pro-atrophic pathway. In conclusion, curcumin represents an effective and safe tool to upregulate Grp94 muscle levels and to maintain muscle function during unweighting. PMID:24710058

  20. Transforming growth factor-{beta} inhibits CCAAT/enhancer-binding protein expression and PPAR{gamma} activity in unloaded bone marrow stromal cells

    SciTech Connect

    Ahdjoudj, S.; Kaabeche, K.; Holy, X.; Fromigue, O.; Modrowski, D.; Zerath, E.; Marie, P.J. . E-mail: pierre.marie@larib.inserm.fr

    2005-02-01

    The molecular mechanisms regulating the adipogenic differentiation of bone marrow stromal cells in vivo remain largely unknown. In this study, we investigated the regulatory effects of transforming growth factor beta-2 (TGF-{beta}2) on transcription factors involved in adipogenic differentiation induced by hind limb suspension in rat bone marrow stromal cells in vivo. Time course real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) analysis of gene expression showed that skeletal unloading progressively increases the expression of CCAAT/enhancer-binding protein (C/EBP){alpha} and C/EBP{beta} {alpha} at 5 days in bone marrow stromal cells resulting in increased peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}2) transcripts at 7 days. TGF-{beta}2 administration in unloaded rats corrected the rise in C/EBP{alpha} and C/EBP{beta} transcripts induced by unloading in bone marrow stromal cells. This resulted in inhibition of PPAR{gamma}2 expression that was associated with increased Runx2 expression. Additionally, the inhibition of C/EBP{alpha} and C/EBP{beta} expression by TGF-{beta}2 was associated with increased PPAR{gamma} serine phosphorylation in bone marrow stromal cells, a mechanism that inhibits PPAR{gamma} transactivating activity. The sequential inhibitory effect of TGF-{beta}2 on C/EBP{alpha}, C/EBP{beta}, and PPAR{gamma}2 resulted in reduced LPL expression and abolition of bone marrow stromal cell adipogenic differentiation, which contributed to prevent bone loss induced by skeletal unloading. We conclude that TGF-{beta}2 inhibits the excessive adipogenic differentiation of bone marrow stromal cells induced by skeletal unloading by inhibiting C/EBP{alpha}, C/EBP{beta}, and PPAR{gamma} expression and activity, which provides a sequential mechanism by which TGF-{beta}2 regulates adipogenic differentiation of bone marrow stromal cells in vivo.

  1. Use of commercial robotics in radioactive waste shipping and receiving

    SciTech Connect

    Berger, J.D.

    1985-03-15

    Radioactive waste shipping and receiving facilities presently planned for commercial and defense nuclear waste will handle waste packages at frequencies far in excess of those in common practice today. Unacceptable personnel exposure to ionizing radiation is projected to occur if current limits for radiation levels at the cask surface and current handling methods are used. To reduce these exposure levels, alternate handling methods are being developed and demonstrated. The production nature of cask receiving operations suggests commercial robotics be incorporated into a remote handling system to reduce predicted worker exposure to acceptable levels, while maintaining or increasing throughput. The first phase of cask handling system development culminated in a proof-of-principle test demonstrating the feasibility of performing cask receiving and unloading operations in a remote and partially automated manner. 6 refs., 12 figs.

  2. Long-term monitoring of feral genetically modified herbicide-tolerant Brassica napus populations around unloading Japanese ports

    PubMed Central

    Katsuta, Kensuke; Matsuo, Kazuhito; Yoshimura, Yasuyuki; Ohsawa, Ryo

    2015-01-01

    Genetically modified, herbicide-tolerant (GMHT) Brassica napus plants originating from seed spill have recently been found along roadsides leading from Japanese ports that unload oilseed rape. Such introductions have potential biodiversity effects (as defined by the Cartagena Protocol): these include replacement of native elements in the biota through competitive suppression or hybridization. We conducted surveys in the period 2006–2011 to assess such threats. We examined shifts in the population distribution and occurrence of GMHT plants in 1,029 volunteer introduced assemblages of B. napus, 1,169 of B. juncea, and 184 of B. rapa around 12 ports. GMHT B. napus was found around 10 of 12 ports, but its proportion in the populations varied greatly by year and location. Over the survey period, the distributions of a pure non-GMHT population around Tobata and a pure GMHT population around Hakata increased significantly. However, there was no common trend of population expansion or contraction around the 12 ports. Furthermore, we found no herbicide tolerant B. juncea and B. rapa plants derived from crosses with GMHT B. napus. Therefore, GMHT B. napus is not invading native vegetation surrounding its populations and not likely to cross with congeners in Japanese environment. PMID:26175624

  3. An Inverse Finite Element u/p-Formulation to Predict the Unloaded State of In Vivo Biological Soft Tissues.

    PubMed

    Vavourakis, Vasileios; Hipwell, John H; Hawkes, David J

    2016-01-01

    Physically realistic patient-specific biomechanical modelling is of paramount importance for many medical applications, where the geometry of tissues or organs is usually constructed from in vivo images. However, it is common for such biological structures to correspond to a deformed state due to being under external loadings. This necessitates the determination of the stress distribution of the known deformed state through an inverse analysis approach. To achieve this, we propose here a generalised finite element displacement/pressure (u/p)-formulation for evaluating the unloaded configuration of in vivo biological soft tissues that exhibit quasi-incompressible behaviour under finite deformations. Validity and applicability of the proposed numerical framework to practical inverse analysis problems in biomechanics is demonstrated through various numerical examples. The corresponding simulations utilise in vivo measurements of patient-specific geometries derived from different medical imaging modalities, and include recovery of the pressure-free configuration of human aortas and the gravity-free shape of the female breast. PMID:26219402

  4. Characterization of solid-phase extraction of Fe(III) by unloaded polyurethane foam as thiocyanate complex.

    PubMed

    de Almeida, Gil Nunes; de Sousa, Leandro M; Pereira Netto, Annibal D; Cassella, Ricardo J

    2007-11-01

    This work presents a detailed study about the adsorption of iron(III)-thiocyanate complexes onto unloaded polyether-type polyurethane foam (PUF). A novel strategy was employed for this purpose, utilizing the adjustment of the plug cylinder of PUF to the arm of an overhead stirrer. The system was characterized in relation to equilibrium and kinetic aspects and it was modeled by applying Langmuir and Freundlich isotherms. The results obtained showed that adsorption occurs on a monolayer and that external transport of the solute from solution to adsorbent was the rate-determining mechanism. A maximum adsorption capacity of 2.06 x 10(-4) mol Fe g(-1) was obtained under established experimental conditions (0.5 mol L(-1) SCN(-) and 0.005 mol L(-1) HCl). Sequential extraction experiments were carried out by changing PUF in time intervals previously defined (5, 20, and 40 min), and the obtained results showed that it is possible to remove around 95% of the Fe(III) in solution through five consecutive extractions of 5 min with five 200 mg PUF cylinders. PMID:17662992

  5. Long-term monitoring of feral genetically modified herbicide-tolerant Brassica napus populations around unloading Japanese ports.

    PubMed

    Katsuta, Kensuke; Matsuo, Kazuhito; Yoshimura, Yasuyuki; Ohsawa, Ryo

    2015-06-01

    Genetically modified, herbicide-tolerant (GMHT) Brassica napus plants originating from seed spill have recently been found along roadsides leading from Japanese ports that unload oilseed rape. Such introductions have potential biodiversity effects (as defined by the Cartagena Protocol): these include replacement of native elements in the biota through competitive suppression or hybridization. We conducted surveys in the period 2006-2011 to assess such threats. We examined shifts in the population distribution and occurrence of GMHT plants in 1,029 volunteer introduced assemblages of B. napus, 1,169 of B. juncea, and 184 of B. rapa around 12 ports. GMHT B. napus was found around 10 of 12 ports, but its proportion in the populations varied greatly by year and location. Over the survey period, the distributions of a pure non-GMHT population around Tobata and a pure GMHT population around Hakata increased significantly. However, there was no common trend of population expansion or contraction around the 12 ports. Furthermore, we found no herbicide tolerant B. juncea and B. rapa plants derived from crosses with GMHT B. napus. Therefore, GMHT B. napus is not invading native vegetation surrounding its populations and not likely to cross with congeners in Japanese environment. PMID:26175624

  6. Time/motion observations of reactor loading, transportation, and dry unloading of an oversized truck spent-fuel shipment

    SciTech Connect

    Lavender, J.C.; Hostick, C.J.; Wakeman, B.H.

    1988-01-01

    This paper presents actual time/motion data for an oversize truck spent-fuel shipment from its origin, Surry, Virginia to its destination, Idaho National Engineering Laboratory (INEL). These data include the receipt of the empty cask at the reactor, wet-loading the cask, over-the-road or in-transit data, and receipt and dry unloading of the shipping cask at the receiving facility. Occupational doses were recorded at the Surry Power Plant as well as at INEL, and public doses were calculated for the in-transit dose analysis. This shipment was one of a series performed in support of a demonstration and evaluation of dry storage at INEL. The oversized shipment consisted of a TN-8L shipping cask loaded with three 10-yr-old pressurized water reactor assemblies. The total distance traveled was {approx}2800 miles, requiring 62 h including stops. The time required to receive and inspect the empty shipping cask and wet-load and release the shipment at the reactor was {approx}14.1 h, and the time to receive the loaded cask, dry-transfer the spent fuel to the storage cask, and release the empty cask and trailer at the INEL facility was {approx}8.2 h.

  7. Seed coat-associated invertases of fava bean control both unloading and storage functions: cloning of cDNAs and cell type-specific expression.

    PubMed

    Weber, H; Borisjuk, L; Heim, U; Buchner, P; Wobus, U

    1995-11-01

    We have studied the molecular physiology of photosynthate unloading and partitioning during seed development of fava bean (Vicia faba). During the prestorage phase, high levels of hexoses in the cotyledons and the apoplastic endospermal space are correlated with activity of cell wall-bound invertase in the seed coat. Three cDNAs were cloned. Sequence comparison revealed genes putatively encoding one soluble and two cell wall-bound isoforms of invertase. Expression was studied in different organs and tissues of developing seeds by RNA gel analysis, in situ hybridization, enzyme assay, and enzyme activity staining. One extracellular invertase gene is expressed during the prestorage phase in the thin-walled parenchyma of the seed coat, a region known to be the site of photoassimilate unloading. We propose a model for an invertase-mediated unloading process during early seed development and the regulation of cotyledonary sucrose metabolism. After unloading from the seed coat, sucrose is hydrolyzed by cell wall-bound invertases. Thus, invertase contributes to establish sink strength in young seeds. The resultant hexoses are loaded into the cotyledons and control carbohydrate partitioning via an influence on the sucrose synthase/sucrose-phosphate synthase pathway. The developmentally regulated degradation of the thin-walled parenchyma expressing the invertase apparently initiates the storage phase. This is characterized by a switch to a low sucrose/hexoses ratio. Feeding hexoses to storage-phase cotyledons in vitro increases the sucrose-phosphate synthase/sucrose synthase ratio and changes carbohydrate partitioning in favor of sucrose. Concomitantly, the transcript level of the major storage product legumin B is downregulated. PMID:8535137

  8. 46 CFR 35.35-42 - Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Restrictions on vessels alongside a tank vessel loading or unloading cargo of Grade A, B, or C-TB/ALL. 35.35-42 Section 35.35-42 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Cargo Handling § 35.35-42 Restrictions on vessels alongside a tank vessel loading or...

  9. Increasing the number of unloading/reambulation cycles does not adversely impact body composition and lumbar bone mineral density but reduces tissue sensitivity

    NASA Astrophysics Data System (ADS)

    Gupta, Shikha; Manske, Sarah L.; Judex, Stefan

    2013-11-01

    A single exposure to hindlimb unloading leads to changes in body mass, body composition and bone, but the consequences of multiple exposures are not yet understood. Within a 18 week period, adult C57BL/6 male mice were exposed to 1 (1x-HLU), 2 (2x-HLU) or 3 (3x-HLU) cycles of 2 weeks of hindlimb unloading (HLU) followed by 4 weeks of reambulation (RA), or served as ambulatory age-matched controls. In vivo μCT longitudinally tracked changes in abdominal adipose and lean tissues, lumbar vertebral apparent volumetric bone mineral density (vBMD) and upper hindlimb muscle cross-sectional area before and after the final HLU and RA cycle. During the final HLU cycle, significant decreases in total adipose tissue and vertebral vBMD in the three experimental groups occurred such that there were no significant between-group differences at the beginning of the final RA cycle. However, the magnitude of the HLU induced losses diminished in mice undergoing their 2nd or 3rd HLU cycle. Irrespective of the number of HLU/RA cycles, total adipose tissue and vertebral vBMD recovered and were no different from age-matched controls after the final RA period. In contrast, upper hindlimb muscle cross-sectional area was significantly lower than controls in all unloaded groups after the final RA period. These results suggest that tissues in the abdominal region are more resilient to multiple bouts of unloading and more amenable to recovery during reambulation than the peripheral musculoskeletal system.

  10. Textile Wastes.

    ERIC Educational Resources Information Center

    Talbot, R. S.

    1978-01-01

    Presents a literature review of wastes from textile industry, covering publications of 1977. This review covers studies such as removing heavy metals in textile wastes, and the biodegradability of six dyes. A list of references is also presented. (HM)

  11. Hazardous Waste

    MedlinePlus

    ... wastes come from products in our homes. Our garbage can include such hazardous wastes as old batteries, ... drain, flush them, or put them in the garbage. See if you can donate or recycle. Many ...

  12. Agricultural Waste.

    PubMed

    Shu, Huajie; Zhang, Panpan; Chang, Chein-Chi; Wang, Renqing; Zhang, Shuping

    2015-10-01

    The management and disposal of agricultural waste are drawn more and more attention because of the increasing yields and negative effects on the environment. However, proper treatments such as converting abundant biomass wastes into biogas through anaerobic digestion technology, can not only avoid the negative impacts, but also convert waste into available resources. This review summarizes the studies of nearly two hundred scholars from the following four aspects: the characterization, reuse, treatment, and management of agricultural waste. PMID:26420088

  13. Up-regulation of ryanodine receptor expression increases the calcium-induced calcium release and spontaneous calcium signals in cerebral arteries from hindlimb unloaded rats.

    PubMed

    Morel, Jean-Luc; Dabertrand, Fabrice; Porte, Yves; Prevot, Anne; Macrez, Nathalie

    2014-08-01

    Microgravity induces a redistribution of blood volume. Consequently, astronauts' body pressure is modified so that the upright blood pressure gradient is abolished, thereby inducing a modification in cerebral blood pressure. This effect is mimicked in the hindlimb unloaded rat model. After a duration of 8 days of unloading, Ca2+ signals activated by depolarization and inositol-1,4,5-trisphosphate intracellular release were increased in cerebral arteries. In the presence of ryanodine and thapsigargin, the depolarization-induced Ca2+ signals remained increased in hindlimb suspended animals, indicating that Ca2+ influx and Ca2+-induced Ca2+ release mechanism were both increased. Spontaneous Ca2+ waves and localized Ca2+ events were also investigated. Increases in both amplitude and frequency of spontaneous Ca2+ waves were measured in hindlimb suspension conditions. After pharmacological segregation of Ca2+ sparks and Ca2+ sparklets, their kinetic parameters were characterized. Hindlimb suspension induced an increase in the frequencies of both Ca2+ localized events, suggesting an increase of excitability. Labeling with bodipy compounds suggested that voltage-dependent Ca2+ channels and ryanodine receptor expressions were increased. Finally, the expression of the ryanodine receptor subtype 1 (RyR1) was increased in hindlimb unloading conditions. Taken together, these results suggest that RyR1 expression and voltage-dependent Ca2+ channels activity are the focal points of the regulation of Ca2+ signals activated by vasoconstriction in rat cerebral arteries with an increase of the voltage-dependent Ca2+ influx. PMID:24233561

  14. Agricultural Wastes.

    ERIC Educational Resources Information Center

    Jewell, W. J.; Switzenbaum, M. S.

    1978-01-01

    Presents a literature review of agricultural wastes, covering publications of 1976-77. Some of the areas covered are: (1) water characteristics and impacts; (2) waste treatment; (3) reuse of agricultural wastes; and (4) nonpoint pollution sources. A list of 150 references is also presented. (HM)

  15. Radioactive wastes

    SciTech Connect

    Devarakonda, M.S.; Hickox, J.A.

    1996-11-01

    This paper provides a review of literature published in 1995 on the subject of radioactive wastes. Topics covered include: national programs; waste repositories; mixed wastes; decontamination and decommissioning; remedial actions and treatment; and environmental occurrence and transport of radionuclides. 155 refs.

  16. Automotive Wastes.

    PubMed

    Guigard, Selma E; Shariaty, Pooya; Niknaddaf, Saeid; Lashaki, Masoud Jahandar; Atkinson, John D; Hashisho, Zaher

    2015-10-01

    A review of the literature from 2014 related to automotive wastes is presented. Topics include solid wastes from autobodies and tires as well as vehicle emissions to soil and air as a result of the use of conventional and alternative fuels. Potential toxicological and health risks related to automotive wastes are also discussed. PMID:26420089

  17. Radioactive Waste.

    ERIC Educational Resources Information Center

    Blaylock, B. G.

    1978-01-01

    Presents a literature review of radioactive waste disposal, covering publications of 1976-77. Some of the studies included are: (1) high-level and long-lived wastes, and (2) release and burial of low-level wastes. A list of 42 references is also presented. (HM)

  18. Feasibility Study For Use Of Commercial Cask Vendor Dry Transfer Systems To Unload Used Fuel Assemblies In L-Area

    SciTech Connect

    Krementz, Dan; Rose, David; Dunsmuir, Mike

    2014-02-06

    The purpose of this study is to determine whether a commercial dry transfer system (DTS) could be used for loading or unloading used nuclear fuel (UNF) in L-Basin and to determine if a DTS pool adapter could be made for L-Basin Transfer Pit #2 that could accommodate a variety of DTS casks and fuel baskets or canisters up to 24” diameter.[1, 2] This study outlines the technical feasibility of accommodating different vendor dry transfer systems in the L-Basin Transfer Bay with a general work scope. It identifies equipment needing development, facility modifications, and describes the needed analyses and calculations. After reviewing the L-Basin Transfer Bay area layout and information on the only DTS system currently in use for the Nuclear Assurance Corporation Legal Weight Truck cask (NAC LWT), the authors conclude that use of a dry transfer cask is feasible. AREVA was contacted and acknowledged that they currently do not have a design for a dry transfer cask for their new Transnuclear Long Cask (TN-LC) cask. Nonetheless, this study accounted for a potential future DTS from AREVA to handle fuel baskets up to 18” in diameter. Due to the layout of the Transfer Bay, it was determined that a DTS cask pool adapter designed specifically for spanning Pit #2 and placed just north of the 70 Ton Cask lid lifting superstructure would be needed. The proposed pool adapter could be used to transition a fuel basket up to 24” in diameter and ~11 feet long from a dry transfer cask to the basin. The 18” and 24” applications of the pool adapter are pending vendor development of dry transfer casks that accommodate these diameters. Once a fuel basket has been lowered into Pit #2 through a pool adapter, a basket cart could be used to move the basket out from under the pool adapter for access by the 5 Ton Crane. The cost to install a dry transfer cask handling system in L-Area capable of handling multiple vendor provided transport and dry transfer casks and baskets with

  19. Substorm recurrence during steady and variable solar wind driving: Evidence for a normal mode in the unloading dynamics of the magnetosphere

    NASA Technical Reports Server (NTRS)

    Klimas, A. J.; Baker, D. N.; Vassiliadis, D.; Roberts, D. A.

    1994-01-01

    Farrugia et al (1993) have recently studied substorm activity driven by the passage of an interplanetary magnetic cloud during which the interplanetary magnetic field turned southward for approximately 18 hours. It was shown that both the epsilon and the VB(sub s) parameters varied slowly on the timescale of a substorm but changed considerably over the interval as a whole. The substorm occurrence rate did not reflect the variation in magnetospheric energy loading rate as measured by these parameters but, rather, remained roughly constant with a 50-min average period. Klimas et al. (1992) showed that the Faraday loop analog model of geomagnetic activity predicts this single unloading rate under various constant loading rates. However, various model parameters were adjusted to yield a 1-hour unloading period in agreement with the Bargatze et al. (1985) linear prediction filters and in approximate agreement with the Farrugia et al. (1993) results. It has since been found necessary to add a slow relaxation mechanism to the Faraday loop model to allow for its approach to a ground state during long periods of inactivity. It is proposed that the relaxation mechanism is provided by slow convection of magnetic flux out of the magnetotail to the dayside magnetosphere. In addition, a rudimentary representation of magnetotail-ionosphere coupling has been added to enable comparison of model output to measured AL. The present study is of the modified Faraday loop model response to solar wind input from the Bargatze et al. data set with comparison of its output to concurrent AL. This study has removed the degree of freedom in parameter choice that had earlier allowed adjustments toward the 1-hour unloading period and has, instead, yielded the 1-hour unloading period under various constant loading rates. It is demonstrated that the second peak of the bimodal Bargatze et al. linear prediction filters at approximately equal 1-hour lag and the approximately constant substorm

  20. Differential regulation of microRNAs in end-stage failing hearts is associated with left ventricular assist device unloading.

    PubMed

    Barsanti, Cristina; Trivella, Maria Giovanna; D'Aurizio, Romina; El Baroudi, Mariama; Baumgart, Mario; Groth, Marco; Caruso, Raffaele; Verde, Alessandro; Botta, Luca; Cozzi, Lorena; Pitto, Letizia

    2015-01-01

    Mechanical unloading by left ventricular assist devices (LVADs) in advanced heart failure (HF), in addition to improving symptoms and end-organ perfusion, is supposed to stimulate cellular and molecular responses which can reverse maladaptive cardiac remodeling. As microRNAs (miRNAs) are key regulators in remodeling processes, a comparative miRNA profiling in transplanted hearts of HF patients with/without LVAD assistance could aid to comprehend underlying molecular mechanisms. Next generation sequencing (NGS) was used to analyze miRNA differential expression in left ventricles of HF patients who underwent heart transplantation directly (n = 9) or following a period of LVAD support (n = 8). After data validation by quantitative real-time PCR, association with functional clinical parameters was investigated. Bioinformatics' tools were then used for prediction of putative targets of modulated miRNAs and relative pathway enrichment. The analysis revealed 13 upregulated and 10 downregulated miRNAs in failing hearts subjected to LVAD assistance. In particular, the expression level of some of them (miR-338-3p, miR-142-5p and -3p, miR-216a-5p, miR-223-3p, miR-27a-5p, and miR-378g) showed correlation with off-pump cardiac index values. Predicted targets of these miRNAs were involved in focal adhesion/integrin pathway and in actin cytoskeleton regulation. The identified miRNAs might contribute to molecular regulation of reverse remodeling and heart recovery mechanisms. PMID:25710008

  1. Velocities of unloaded muscle filaments are not limited by drag forces imposed by myosin cross-bridges

    PubMed Central

    Brizendine, Richard K.; Alcala, Diego B.; Carter, Michael S.; Haldeman, Brian D.; Facemyer, Kevin C.; Baker, Josh E.; Cremo, Christine R.

    2015-01-01

    It is not known which kinetic step in the acto-myosin ATPase cycle limits contraction speed in unloaded muscles (V0). Huxley’s 1957 model [Huxley AF (1957) Prog Biophys Biophys Chem 7:255–318] predicts that V0 is limited by the rate that myosin detaches from actin. However, this does not explain why, as observed by Bárány [Bárány M (1967) J Gen Physiol 50(6, Suppl):197–218], V0 is linearly correlated with the maximal actin-activated ATPase rate (vmax), which is limited by the rate that myosin attaches strongly to actin. We have observed smooth muscle myosin filaments of different length and head number (N) moving over surface-attached F-actin in vitro. Fitting filament velocities (V) vs. N to a detachment-limited model using the myosin step size d = 8 nm gave an ADP release rate 8.5-fold faster and ton (myosin’s attached time) and r (duty ratio) ∼10-fold lower than previously reported. In contrast, these data were accurately fit to an attachment-limited model, V = N·v·d, over the range of N found in all muscle types. At nonphysiologically high N, V = L/ton rather than d/ton, where L is related to the length of myosin’s subfragment 2. The attachment-limited model also fit well to the [ATP] dependence of V for myosin-rod cofilaments at three fixed N. Previously published V0 vs. vmax values for 24 different muscles were accurately fit to the attachment-limited model using widely accepted values for r and N, giving d = 11.1 nm. Therefore, in contrast with Huxley’s model, we conclude that V0 is limited by the actin–myosin attachment rate. PMID:26294254

  2. Differential Regulation of MicroRNAs in End-Stage Failing Hearts Is Associated with Left Ventricular Assist Device Unloading

    PubMed Central

    Barsanti, Cristina; Trivella, Maria Giovanna; D'Aurizio, Romina; El Baroudi, Mariama; Baumgart, Mario; Groth, Marco; Caruso, Raffaele; Verde, Alessandro; Botta, Luca; Cozzi, Lorena; Pitto, Letizia

    2015-01-01

    Mechanical unloading by left ventricular assist devices (LVADs) in advanced heart failure (HF), in addition to improving symptoms and end-organ perfusion, is supposed to stimulate cellular and molecular responses which can reverse maladaptive cardiac remodeling. As microRNAs (miRNAs) are key regulators in remodeling processes, a comparative miRNA profiling in transplanted hearts of HF patients with/without LVAD assistance could aid to comprehend underlying molecular mechanisms. Next generation sequencing (NGS) was used to analyze miRNA differential expression in left ventricles of HF patients who underwent heart transplantation directly (n = 9) or following a period of LVAD support (n = 8). After data validation by quantitative real-time PCR, association with functional clinical parameters was investigated. Bioinformatics' tools were then used for prediction of putative targets of modulated miRNAs and relative pathway enrichment. The analysis revealed 13 upregulated and 10 downregulated miRNAs in failing hearts subjected to LVAD assistance. In particular, the expression level of some of them (miR-338-3p, miR-142-5p and -3p, miR-216a-5p, miR-223-3p, miR-27a-5p, and miR-378g) showed correlation with off-pump cardiac index values. Predicted targets of these miRNAs were involved in focal adhesion/integrin pathway and in actin cytoskeleton regulation. The identified miRNAs might contribute to molecular regulation of reverse remodeling and heart recovery mechanisms. PMID:25710008

  3. Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery.

    PubMed

    Lewis, Ryan C; Gaffney, Shannon H; Le, Matthew H; Unice, Ken M; Paustenbach, Dennis J

    2012-09-01

    Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from <0.001 to 2.9mg/m(3), and, in all but one case, resulted in concentrations below the current U.S. Occupational Safety and Health Administration's Permissible Exposure Limits and the American Conference of Governmental Industrial Hygienists' Threshold Limit Values. The arithmetic mean total dust concentration resulting from long-term personal samples was 0.31mg/m(3). The data presented here are the most complete set of its kind in the open literature, and are useful for understanding the potential exposures during solid catalyst handling activities at this petroleum refinery and perhaps other modern refineries during the timeframe examined. PMID:22177528

  4. Skeletal muscle myostatin mRNA expression is fiber-type specific and increases during hindlimb unloading

    NASA Technical Reports Server (NTRS)

    Carlson, C. J.; Booth, F. W.; Gordon, S. E.

    1999-01-01

    Transgenic mice lacking a functional myostatin (MSTN) gene demonstrate greater skeletal muscle mass resulting from muscle fiber hypertrophy and hyperplasia (McPherron, A. C., A. M. Lawler, and S. -J. Lee. Nature 387: 83-90, 1997). Therefore, we hypothesized that, in normal mice, MSTN may act as a negative regulator of muscle mass. Specifically, we hypothesized that the predominately slow (type I) soleus muscle, which demonstrates greater atrophy than the fast (type II) gastrocnemius-plantaris complex (Gast/PLT), would show more elevation in MSTN mRNA abundance during hindlimb unloading (HU). Surprisingly, MSTN mRNA was not detectable in weight-bearing or HU soleus muscle, which atrophied 42% by the 7th day of HU in female ICR mice. In contrast, MSTN mRNA was present in weight-bearing Gast/PLT muscle and was significantly elevated (67%) at 1 day but not at 3 or 7 days of HU. However, the Gast/PLT muscle had only atrophied 17% by the 7th day of HU. Because the soleus is composed only of type I and IIa fibers, whereas the Gast/PLT expresses type IId/x and IIb in addition to type I and IIa, it was necessary to perform a more careful analysis of the relationship between MSTN mRNA levels and myosin heavy-chain (MHC) isoform expression (as a marker of fiber type). A significant correlation (r = 0.725, P < 0. 0005) was noted between the percentage of MHC isoform IIb expression and MSTN mRNA abundance in several muscles of the mouse hindlimb. These results indicate that MSTN expression is not strongly associated with muscle atrophy induced by HU; however, it is strongly associated with MHC isoform IIb expression in normal muscle.

  5. Agricultural Waste.

    PubMed

    Xue, Ling; Zhang, Panpan; Shu, Huajie; Chang, Chein-Chi; Wang, Renqing; Zhang, Shuping

    2016-10-01

    In recent years, the quantity of agricultural waste has been rising rapidly all over the world. As a result, the environmental problems and negative impacts of agricultural waste are drawn more and more attention. Therefore, there is a need to adopt proper approaches to reduce and reuse agricultural waste. This review presented about 200 literatures published in 2015 relating to the topic of agricultural waste. The review examined research on agricultural waste in 2015 from the following four aspects: the characterization, reuse, treatment, and management. Researchers highlighted the importance to reuse agricultural waste and investigated the potential to utilize it as biofertilizers, cultivation material, soil amendments, adsorbent, material, energy recycling, enzyme and catalyst etc. The treatment of agricultural waste included carbonization, biodegradation, composting hydrolysis and pyrolysis. Moreover, this review analyzed the differences of the research progress in 2015 from 2014. It may help to reveal the new findings and new trends in this field in 2015 comparing to 2014. PMID:27620093

  6. The international trade in toxic waste: the case of Sihanoukville, Cambodia.

    PubMed

    Hess, J; Frumkin, H

    2000-01-01

    In December 1998, 2,700 metric tons of industrial waste containing high levels of mercury and other metals and possibly other toxic compounds were shipped illegally from Taiwan to Sihanoukville, Cambodia. There the waste was unloaded and transferred to a nearby inland dumpsite. An estimated 2,000 Sihanoukville residents were exposed to the waste occupationally or environmentally, and at least six deaths and hundreds of injuries have been associated with the incident. The authors describe the human exposures and associated morbidity and mortality, recount the medical and public health response, and consider the issues complicating epidemiologic analysis of the incident. They also consider the major issues highlighted by the incident, including the trade in toxic waste between developed and less developed countries, the factors that shape emergency public health responses in resource-poor environments, and the importance of prevention and preparedness in containing emergencies in developing countries. PMID:11114126

  7. Knee braces - unloading

    MedlinePlus

    ... most people talk about the arthritis in their knees, they are referring to a type of arthritis ... is caused by wear and tear inside your knee joints. Cartilage, the firm, rubbery tissue that cushions ...

  8. Knee braces - unloading

    MedlinePlus

    ... is caused by wear and tear inside your knee joints. Cartilage, the firm, rubbery tissue that cushions all of your bones and joints, lets the bones glide over one another. If ... the knee become weaker. Over time, your whole knee becomes ...

  9. Radioactive Wastes.

    PubMed

    Choudri, B S; Baawain, Mahad

    2016-10-01

    Papers reviewed herein present a general overview of radioactive waste activities around the world in 2015. These include safety assessments, decommission and decontamination of nuclear facilities, fusion facilities, transportation and management solutions for the final disposal of low and high level radioactive wastes (LLW and HLW), interim storage and final disposal options for spent fuel (SF), and tritiated wastes, with a focus on environmental impacts due to the mobility of radionuclides in water, soil and ecosystem alongwith other progress made in the management of radioactive wastes. PMID:27620100

  10. Radioactive Wastes.

    PubMed

    Choudri, B S; Baawain, Mahad

    2015-10-01

    Papers reviewed herein present a general overview of radioactive waste activities around the world in 2014. These include safety assessments, decommission and decontamination of nuclear facilities, fusion facilities, transportation and management solutions for the final disposal of low and high level radioactive wastes (LLW and HLW), interim storage and final disposal options for spent fuel (SF), and tritiated wastes, with a focus on environmental impacts due to the mobility of radionuclides in water, soil and ecosystem alongwith other progress made in the management of radioactive wastes. PMID:26420096

  11. Expression of a calpastatin transgene slows muscle wasting and obviates changes in myosin isoform expression during murine muscle disuse

    NASA Technical Reports Server (NTRS)

    Tidball, James G.; Spencer, Melissa J.

    2002-01-01

    Muscle wasting is a prominent feature of several systemic diseases, neurological damage and muscle disuse. The contribution of calpain proteases to muscle wasting in any instance of muscle injury or disease has remained unknown because of the inability to specifically perturb calpain activity in vivo. We have generated a transgenic mouse with muscle-specific overexpression of calpastatin, which is the endogenous inhibitor of calpains, and induced muscle atrophy by unloading hindlimb musculature for 10 days. Expression of the transgene resulted in increases in calpastatin concentration in muscle by 30- to 50-fold, and eliminated all calpain activity that was detectable on zymograms. Muscle fibres in ambulatory, transgenic mice were smaller in diameter, but more numerous, so that muscle mass did not differ between transgenic and non-transgenic mice. This is consistent with the role of the calpain-calpastatin system in muscle cell fusion that has been observed in vitro. Overexpression of calpastatin reduced muscle atrophy by 30 % during the 10 day unloading period. In addition, calpastatin overexpression completely prevented the shift in myofibrillar myosin content from slow to fast isoforms, which normally occurs in muscle unloading. These findings indicate that therapeutics directed toward regulating the calpain-calpastatin system may be beneficial in preventing muscle mass loss in muscle injury and disease.

  12. Total Mechanical Unloading Minimizes Metabolic Demand of Left Ventricle and Dramatically Reduces Infarct Size in Myocardial Infarction

    PubMed Central

    Kakino, Takamori; Arimura, Takahiro; Sakamoto, Takafumi; Nishikawa, Takuya; Sakamoto, Kazuo; Ikeda, Masataka; Kishi, Takuya; Ide, Tomomi; Sunagawa, Kenji

    2016-01-01

    Background Left ventricular assist device (LVAD) mechanically unloads the left ventricle (LV). Theoretical analysis indicates that partial LVAD support (p-LVAD), where LV remains ejecting, reduces LV preload while increases afterload resulting from the elevation of total cardiac output and mean aortic pressure, and consequently does not markedly decrease myocardial oxygen consumption (MVO2). In contrast, total LVAD support (t-LVAD), where LV no longer ejects, markedly decreases LV preload volume and afterload pressure, thereby strikingly reduces MVO2. Since an imbalance in oxygen supply and demand is the fundamental pathophysiology of myocardial infarction (MI), we hypothesized that t-LVAD minimizes MVO2 and reduces infarct size in MI. The purpose of this study was to evaluate the differential impact of the support level of LVAD on MVO2 and infarct size in a canine model of ischemia-reperfusion. Methods In 5 normal mongrel dogs, we examined the impact of LVAD on MVO2 at 3 support levels: Control (no LVAD support), p-LVAD and t-LVAD. In another 16 dogs, ischemia was induced by occluding major branches of the left anterior descending coronary artery (90 min) followed by reperfusion (300 min). We activated LVAD from the beginning of ischemia until 300 min of reperfusion, and compared the infarct size among 3 different levels of LVAD support. Results t-LVAD markedly reduced MVO2 (% reduction against Control: -56 ± 9%, p<0.01) whereas p-LVAD did less (-21 ± 14%, p<0.05). t-LVAD markedly reduced infarct size compared to p-LVAD (infarct area/area at risk: Control; 41.8 ± 6.4, p-LVAD; 29.1 ± 5.6 and t-LVAD; 5.0 ± 3.1%, p<0.01). Changes in creatine kinase-MB paralleled those in infarct size. Conclusions Total LVAD support that minimizes metabolic demand maximizes the benefit of LVAD in the treatment of acute myocardial infarction. PMID:27124411

  13. Noninvasive continuous versus intermittent arterial pressure monitoring: evaluation of the vascular unloading technique (CNAP device) in the emergency department

    PubMed Central

    2014-01-01

    Background Monitoring cardiovascular function in acutely ill patients in the emergency department (ED) is of paramount importance. Arterial pressure (AP) is usually monitored using intermittent oscillometric measurements with an upper arm cuff. The vascular unloading technique (VUT) allows continuous noninvasive AP monitoring. In this study, we compare continuous AP measurements obtained by VUT with intermittent oscillometric AP measurements in ED patients. In addition, we aimed to investigate whether continuous noninvasive AP monitoring allows detection of relevant hypotensive episodes that might be missed with intermittent AP monitoring. Methods In a German university hospital, 130 ED patients who required AP monitoring were analyzed in this prospective method comparison study. Continuous AP monitoring was performed using VUT (CNAP technology; CNSystems Medizintechnik AG, Graz, Austria) over a 2-hour period. The oscillometric AP values were recorded simultaneously every 15 minutes for the comparison of both methods. For statistical evaluation, Bland-Altman plots accounting for repeated AP measurements per individual were used. Results The mean difference (±standard deviation) between AP measurements obtained by VUT and oscillometric AP measurements was -5 mmHg (±22 mmHg) for systolic AP (SAP), -2 mmHg (±15 mmHg) for diastolic AP (DAP), and -6 mmHg (±16 mmHg) for mean AP (MAP), respectively. In the interval between two oscillometric measurements, the VUT device detected hypotensive episodes (≥4 minutes) defined as either SAP <90 mmHg or MAP <65 mmHg in 30 patients and 16 patients, respectively. In 11 (SAP <90 mmHg) and 6 (MAP <65 mmHg) of these patients, hypotension was also detected by the subsequent intermittent oscillometric AP measurement. Conclusions VUT using the CNAP system for noninvasive continuous AP measurement shows reasonable agreement with intermittent oscillometric measurements in acutely ill ED patients. Continuous AP monitoring

  14. Effect of 17 days of bed rest on peak isometric force and unloaded shortening velocity of human soleus fibers

    NASA Technical Reports Server (NTRS)

    Widrick, J. J.; Romatowski, J. G.; Bain, J. L.; Trappe, S. W.; Trappe, T. A.; Thompson, J. L.; Costill, D. L.; Riley, D. A.; Fitts, R. H.

    1997-01-01

    The purpose of this study was to examine the effect of prolonged bed rest (BR) on the peak isometric force (P0) and unloaded shortening velocity (V0) of single Ca(2+)-activated muscle fibers. Soleus muscle biopsies were obtained from eight adult males before and after 17 days of 6 degrees head-down BR. Chemically permeabilized single fiber segments were mounted between a force transducer and position motor, activated with saturating levels of Ca2+, and subjected to slack length steps. V0 was determined by plotting the time for force redevelopment vs. the slack step distance. Gel electrophoresis revealed that 96% of the pre- and 87% of the post-BR fibers studied expressed only the slow type I myosin heavy chain isoform. Fibers with diameter > 100 microns made up only 14% of this post-BR type I population compared with 33% of the pre-BR type I population. Consequently, the post-BR type I fibers (n = 147) were, on average, 5% smaller in diameter than the pre-BR type I fibers (n = 218) and produced 13% less absolute P0. BR had no overall effect on P0 per fiber cross-sectional area (P0/CSA), even though half of the subjects displayed a decline of 9-12% in P0/CSA after BR. Type I fiber V0 increased by an average of 34% with BR. Although the ratio of myosin light chain 3 to myosin light chain 2 also rose with BR, there was no correlation between this ratio and V0 for either the pre- or post-BR fibers. In separate fibers obtained from the original biopsies, quantitative electron microscopy revealed a 20-24% decrease in thin filament density, with no change in thick filament density. These results raise the possibility that alterations in the geometric relationships between thin and thick filaments may be at least partially responsible for the elevated V0 of the post-BR type I fibers.

  15. Chronic hemodynamic unloading regulates the morphologic development of newborn mouse hearts transplanted into the ear of isogeneic adult mice.

    PubMed Central

    Rossi, M. A.

    1992-01-01

    The morphologic development of newborn mouse hearts transplanted into the pinna of the ears of isogeneic adult mice was assessed in comparison to in situ ventricular myocardium of recipients. The grafted hearts became vascularized from the auricular artery at the base of the ear, and although these preparations appeared not to be intrinsically innervated, most of them showed grossly visible pulsatile activity. Since they were not subjected to hemodynamic load due to working against a pressure gradient, this technique provided an interesting experimental model for studies on the growth of chronically unloaded tissue. The ultrastructure of the myocardium from neonatal mouse hearts, which were fixed immediately after dissection, revealed no differences in comparison to previously published observations. By 2 months, there was virtually no change in the myocardial cell size as compared with newborn mouse cardiac tissue. The heterotopic hearts showed a mature ultrastructural appearance, with parallel bands of myofibrils alternating with rows of mitochondria and differentiated intercalated discs comparable to in situ myocardium. The interstitial space was widened due to fibrous tissue, with activated fibroblasts and a few mononuclear cells. In contrast, by 6 months after transplantation, the heterotopic myocardium showed a dispersion of the measured cell diameter of myocytes, with atrophy of a certain population of cells and hypertrophy in others; nevertheless, the mean cell diameter was similar to that observed in 2-month grafts. The myocytes showed significant dissociation from each other in fibrous tissue and a cellular infiltrate composed predominantly of mononuclear cells, and greater variability of the parallel arrangement of cells. They often contained myofibrils coursing in different directions rather than in parallel. Normal-sized or predominantly atrophic degenerated myocytes, characterized by a wide variety of ultrastructural alterations, were present. By 12

  16. Members of the flight and ground crews prepare to unload equipment from NASA's B377SGT Super Guppy T

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Members of the flight and ground crews prepare to unload equipment from NASA's B377SGT Super Guppy Turbine cargo aircraft on the ramp at NASA's Dryden Flight Research Center at Edwards Air Force Base, Calif. The outsize cargo plane had delivered the latest version of the X-38 flight test vehicle to NASA Dryden when this photo was taken on June 11, 2000. The B-377SGT Super Guppy Turbine evolved from the 1960s-vintage Pregnant Guppy, Mini Guppy and Super Guppy, used for transporting sections of the Saturn rocket used for the Apollo program moon launches and other outsized cargo. The various Guppies were modified from 1940's and 50's-vintage Boeing Model 377 and C-97 Stratocruiser airframes by Aero Spacelines, Inc., which operated the aircraft for NASA. NASA's Flight Research Center assisted in certification testing of the first Pregnant Guppy in 1962. One of the turboprop-powered Super Guppies, built up from a YC-97J airframe, last appeared at Dryden in May, 1976 when it was used to transport the HL-10 and X-24B lifting bodies from Dryden to the Air Force Museum at Wright-Patterson Air Force Base, Ohio. NASA's present Super Guppy Turbine, the fourth and last example of the final version, first flew in its outsized form in 1980. It and its three sister ships were built in the 1970s for Europe's Airbus Industrie to ferry outsized structures for Airbus jetliners to the final assembly plant in Toulouse, France. It later was acquired by the European Space Agency, and then acquired by NASA in late 1997 for transport of large structures for the International Space Station to the launch site. It replaced the earlier-model Super Guppy, which has been retired and is used for spare parts. NASA's Super Guppy Turbine carries NASA registration number N941NA, and is based at Ellington Field near the Johnson Space Center. For more information on NASA's Super Guppy Turbine, log onto the Johnson Space Center Super Guppy web page at http://spaceflight.nasa.gov/station/assembly/superguppy/

  17. Repository waste-handling operations, 1998

    SciTech Connect

    Cottam, A.E.; Connell, L.

    1986-04-01

    The Civilian Radioactive Waste Management Program Mission Plan and the Generic Requirements for a Mined Geologic Disposal System state that beginning in 1998, commercial spent fuel not exceeding 70,000 metric tons of heavy metal, or a quantity of solidified high-level radioactive waste resulting from the reprocessing of such a quantity of spent fuel, will be shipped to a deep geologic repository for permanent storage. The development of a waste-handling system that can process 3000 metric tons of heavy metal annually will require the adoption of a fully automated approach. The safety and minimum exposure of personnel will be the prime goals of the repository waste handling system. A man-out-of-the-loop approach will be used in all operations including the receipt of spent fuel in shipping casks, the inspection and unloading of the spent fuel into automated hot-cell facilities, the disassembly of spent fuel assemblies, the consolidation of fuel rods, and the packaging of fuel rods into heavy-walled site-specific containers. These containers are designed to contain the radionuclides for up to 1000 years. The ability of a repository to handle more than 6000 pressurized water reactor spent-fuel rods per day on a production basis for approximately a 23-year period will require that a systems approach be adopted that combines space-age technology, robotics, and sophisticated automated computerized equipment. New advanced inspection techniques, maintenance by robots, and safety will be key factors in the design, construction, and licensing of a repository waste-handling facility for 1998.

  18. The role of alterations in mitochondrial dynamics and PGC-1α over-expression in fast muscle atrophy following hindlimb unloading

    PubMed Central

    Cannavino, Jessica; Brocca, Lorenza; Sandri, Marco; Grassi, Bruno; Bottinelli, Roberto; Pellegrino, Maria Antonietta

    2015-01-01

    The mechanisms triggering disuse muscle atrophy remain of debate. It is becoming evident that mitochondrial dysfunction may regulate pathways controlling muscle mass. We have recently shown that mitochondrial dysfunction plays a major role in disuse atrophy of soleus, a slow, oxidative muscle. Here we tested the hypothesis that hindlimb unloading-induced atrophy could be due to mitochondrial dysfunction in fast muscles too, notwithstanding their much lower mitochondrial content. Gastrocnemius displayed atrophy following both 3 and 7 days of unloading. SOD1 and catalase up-regulation, no H2O2 accumulation and no increase of protein carbonylation suggest the antioxidant defence system efficiently reacted to redox imbalance in the early phases of disuse. A defective mitochondrial fusion (Mfn1, Mfn2 and OPA1 down-regulation) occurred together with an impairment of OXPHOS capacity. Furthermore, at 3 days of unloading higher acetyl-CoA carboxylase (ACC) phosphorylation was found, suggesting AMP-activated protein kinase (AMPK) pathway activation. To test the role of mitochondrial alterations we used Tg-mice overexpressing PGC-1α because of the known effect of PGC-1α on stimulation of Mfn2 expression. PGC-α overexpression was sufficient to prevent (i) the decrease of pro-fusion proteins (Mfn1, Mfn2 and OPA1), (ii) activation of the AMPK pathway, (iii) the inducible expression of MuRF1 and atrogin1 and of authopagic factors, and (iv) any muscle mass loss in response to disuse. As the effects of increased PGC-1α activity were sustained throughout disuse, compounds inducing PGC-1α expression could be useful to treat and prevent muscle atrophy also in fast muscles. PMID:25565653

  19. Left anterior descending coronary artery blood flow and left ventricular unloading during extracorporeal membrane oxygenation support in a swine model of acute cardiogenic shock.

    PubMed

    Brehm, Christoph; Schubert, Sarah; Carney, Elizabeth; Ghodsizad, Ali; Koerner, Michael; McCoach, Robert; El-Banayosy, Aly

    2015-02-01

    The impact of extracorporeal membrane oxygenation (ECMO) support on coronary blood flow and left ventricular unloading is still debated. This study aimed to further characterize the influence of ECMO on coronary artery blood flow and its ability to unload the left ventricle in a short-term model of acute cardiogenic shock. Seven anesthetized pigs were intubated and then underwent median sternotomy and cannulation for venoarterial (VA) ECMO. Flow in the left anterior descending (LAD) artery, left atrial pressure (LAP), left ventricular end-diastolic pressure (LVEDP), and mean arterial pressure (MAP) were measured before and after esmolol-induced cardiac dysfunction and after initiating VA-ECMO support. Induction of acute cardiogenic shock was associated with short-term increases in LAP from 8 ± 4 mm Hg to 18 ± 14 mm Hg (P = 0.9) and LVEDP from 5 ± 2 mm Hg to 13 ± 17 mm Hg (P = 0.9), and a decrease in MAP from 63 ± 16 mm Hg to 50 ± 24 mm Hg (P = 0.3). With VA-ECMO support, blood flow in the LAD increased from 28 ± 25 mL/min during acute unsupported cardiogenic shock to 67 ± 50 mL/min (P = 0.003), and LAP and LVEDP decreased to 8 + 5 mm Hg (P = 0.7) and 5 ± 3 mm Hg (P = 0.5), respectively. In this swine model of acute cardiogenic shock, VA-ECMO improved coronary blood flow and provided some degree of left ventricular unloading for the short duration of the study. PMID:24935151

  20. Effects of Unloading on Knee Articular Cartilage T1rho and T2 Magnetic Resonance Imaging Relaxation Times: A Case Series

    PubMed Central

    SOUZA, RICHARD B.; BAUM, THOMAS; WU, SAMUEL; FEELEY, BRIAN T.; KADEL, NANCY; LI, XIAOJUAN; LINK, THOMAS M.; MAJUMDAR, SHARMILA

    2013-01-01

    STUDY DESIGN Case series. BACKGROUND It has been shown in rodent and canine models that cartilage composition is significantly altered in response to long-term unloading. To date, however, no in vivo human studies have investigated this topic. The objective of this case series was to determine the influence of unloading and reloading on T1rho and T2 relaxation times of articular cartilage in healthy young joints. CASE DESCRIPTION Ten patients who required 6 to 8 weeks of non–weight bearing (NWB) for injuries affecting the distal lower extremity participated in the study. Quantitative T1rho and T2 imaging of the ipsilateral knee joint was performed at 3 time points: (1) prior to surgery (baseline), (2) immediately after a period of NWB (post-NWB), and (3) after 4 weeks of full weight bearing (post-FWB). Cartilage regions of interest were segmented and overlaid on T1rho and T2 relaxation time maps for quantification. Descriptive statistics are provided for all changes. OUTCOMES Increases of 5% to 10% in T1rho times of all femoral and tibial compartments were noted post-NWB. All values returned to near-baseline levels post-FWB. Increases in medial tibia T2 times were noted post-NWB and remained elevated post-FWB. The load-bearing regions showed the most significant changes in response to unloading, with increases of up to 12%. DISCUSSION The observation of a transient shift in relaxation times confirms that cartilage composition is subject to alterations based on loading conditions. These changes appear to be mostly related to proteoglycan content and more localized to the load-bearing regions. However, following 4 weeks of full weight bearing, relaxation times of nearly all regions had returned to baseline levels, demonstrating reversibility in compositional fluctuations. LEVEL OF EVIDENCE Therapy, level 4. PMID:22402583

  1. Slope of the Anterior Mitral Valve Leaflet: A New Measurement of Left Ventricular Unloading for Left Ventricular Assist Devices and Systolic Dysfunction

    PubMed Central

    Bradley, Elisa A.; Novak, Eric L.; Rasalingam, Ravi; Cedars, Ari M.; Ewald, Gregory A.; Silvestry, Scott C.; Joseph, Susan M.

    2014-01-01

    Left ventricular assist device (LVAD)-supported patients are evaluated routinely with use of transthoracic echocardiography. Values of left ventricular unloading in this unique patient population are needed to evaluate LVAD function and assist in patient follow-up. We introduce a new M-mode measurement, the slope of the anterior mitral valve leaflet (SLAM), and compare its efficacy with that of other standard echocardiographically evaluated values for left ventricular loading, including E/e′ and pulmonary artery systolic pressures. Average SLAM values were determined retrospectively for cohorts of random, non-LVAD patients with moderately to severely impaired left ventricular ejection fraction (LVEF) (<0.35, n=60). In addition, pre- and post-LVAD implantation echocardiographic images of 81 patients were reviewed. The average SLAM in patients with an LVEF <0.35 was 11.6 cm/s (95% confidence interval, 10.4–12.8); SLAM had a moderately strong correlation with E/e′ in these patients. Implantation of LVADs significantly increased the SLAM from 7.3 ± 2.44 to 14.7 ± 5.01 cm/s (n=42, P <0.0001). The LVAD-supported patients readmitted for exacerbation of congestive heart failure exhibited decreased SLAM from 12 ± 3.93 to 7.3 ± 3.5 cm/s (n=6, P=0.041). In addition, a cutpoint of 10 cm/s distinguished random patients with LVEF <0.35 from those in end-stage congestive heart failure (pre-LVAD) with an 88% sensitivity and a 55% specificity. Evaluating ventricular unloading in LVAD patients remains challenging. Our novel M-mode value correlates with echocardiographic values of left ventricular filling in patients with moderate-to-severe systolic function and dynamically improves with the ventricular unloading of an LVAD. PMID:24955040

  2. Reduced expression of MyHC slow isoform in rat soleus during unloading is accompanied by alterations of endogenous inhibitors of calcineurin/NFAT signaling pathway.

    PubMed

    Lomonosova, Yulia N; Turtikova, Olga V; Shenkman, Boris S

    2016-04-01

    Under muscle disuse conditions decrease of expression of MyHC of slow type, and sometimes of type IIa, as well as upregulation of expression of IIb and IId/x isoforms were observed. Through dephosphorylation and entry of NFAT molecules to the nucleus calcineurin/NFATc1 signaling pathway promotes upregulation of the slow MyHC expression. We supposed that downregulation of calcineurin pathway took place during unloading. The study was aimed to analyze the states of the myonuclear NFAT inhibitors calsarcin I (CSI) and calsarcin II (CSII) (also referred to as myozenin II and I) and GSK3β in rat soleus during hindlimb suspension (HS). Male Wistar rats were subjected to 3, 7 and 14 day of HS. We found that after 3 days of HS the content of CSII mRNA twofold increased in soleus as compared to the controls. This level was increased by more than fivefold (as compared to control) after 2 weeks of HS. The increase of CSII mRNA expression may be explained as the mechanism of stabilization of fast phenotype. We found that from the 3 day till 14 day of HS the content of MuRF-1 and MuRF-2 in the nuclear fraction fourfold to fivefold increased in HS soleus. We supposed that nuclear import of the MuRFs allows to promote CSII expression during unloading. We also observed the decline of the phosphorylated GSK3β content in the nuclear extract of the soleus tissue. Thus decline of slow MyHC expression characteristic for the unloading conditions is accompanied with the increased expression and activation of the factors known to prevent NFAT accumulation in the myonuclei. PMID:26589960

  3. Waste segregation

    SciTech Connect

    Clark, D.E.; Colombo, P.

    1982-01-01

    A scoping study has been undertaken to determine the state-of-the-art of waste segregation technology as applied to the management of low-level waste (LLW). Present-day waste segregation practices were surveyed through a review of the recent literature and by means of personal interviews with personnel at selected facilities. Among the nuclear establishments surveyed were Department of Energy (DOE) laboratories and plants, nuclear fuel cycle plants, public and private laboratories, institutions, industrial plants, and DOE and commercially operated shallow land burial sites. These survey data were used to analyze the relationship between waste segregation practices and waste treatment/disposal processes, to assess the developmental needs for improved segregation technology, and to evaluate the costs and benefits associated with the implementation of waste segregation controls. This task was planned for completion in FY 1981. It should be noted that LLW management practices are now undergoing rapid change such that the technology and requirements for waste segregation in the near future may differ significantly from those of the present day. 8 figures.

  4. Nuclear waste

    SciTech Connect

    Not Available

    1991-09-01

    Radioactive waste is mounting at U.S. nuclear power plants at a rate of more than 2,000 metric tons a year. Pursuant to statute and anticipating that a geologic repository would be available in 1998, the Department of Energy (DOE) entered into disposal contracts with nuclear utilities. Now, however, DOE does not expect the repository to be ready before 2010. For this reason, DOE does not want to develop a facility for monitored retrievable storage (MRS) by 1998. This book is concerned about how best to store the waste until a repository is available, congressional requesters asked GAO to review the alternatives of continued storage at utilities' reactor sites or transferring waste to an MRS facility, GAO assessed the likelihood of an MRSA facility operating by 1998, legal implications if DOE is not able to take delivery of wastes in 1998, propriety of using the Nuclear Waste Fund-from which DOE's waste program costs are paid-to pay utilities for on-site storage capacity added after 1998, ability of utilities to store their waste on-site until a repository is operating, and relative costs and safety of the two storage alternatives.

  5. Fragmentation and Cataclasis of Lava Domes: Field Evidence of Conduit-Margin Faulting and Cryptodome Unloading at Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Pallister, J. S.; Hagstrum, J.; Cashman, K.; Tuffen, H.

    2007-12-01

    for many of the earthquakes at MSH. Additionally, grain-flow textures in the bounding ultracataclasite fault zones suggest that observed periods of aseismic extrusion were accommodated by creep on these faults. In contrast, Pine Creek age (~2.5 ka) dome dacite exposed over a large area at the mouth of the MSH crater is pervasively fractured over paleo-depths of >300m. Like the dacite of the current eruption, this rock has a microcrystalline groundmass, indicative of extensive shallow crystallization and subsurface solidification. However, the extent and character of fragmentation is unrelated to shear along conduit margins. Instead, a multi- stage history of brittle deformation consists of: 1) early 10-20cm thick subhorizontal zones of sandy cataclasite that repeat at intervals of meters to tens of meters within pervasively shattered dacite, 2) early cross-cutting high- angle faults with slickensides and <1mm pseudotachylite seams, and 3) later cross-cutting planar faults. We suggest that early cataclasis was produced by rapid unloading of the still-hot dome during a Pine-Creek age sector collapse and that the early high-angle faults represent boundaries of large mega-blocks that had begun to detach within the source dome. Together with mapped Pine Creek avalanche deposts nearby (Hausback, 2000), these features suggest that a transition from avalanche to still-intact Pine-Creek age cryptodome is exposed in the mouth of the MSH crater.

  6. Quantitative changes of GABA-immunoreactive cells in the hindlimb representation of the rat somatosensory cortex after 14-day hindlimb unloading by tail suspension

    NASA Technical Reports Server (NTRS)

    D'Amelio, F.; Fox, R. A.; Wu, L. C.; Daunton, N. G.

    1996-01-01

    The present study was aimed at evaluating quantitatively gamma-aminobutyric acid (GABA) immunoreactivity in the hindlimb representation of the rat somatosensory cortex after 14 days of hindlimb unloading by tail suspension. A reduction in the number of GABA-immunoreactive cells with respect to the control animals was observed in layer Va and Vb. GABA-containing terminals were also reduced in the same layers, particularly those terminals surrounding the soma and apical dendrites of pyramidal cells in layer Vb. On the basis of previous morphological and behavioral studies of the neuromuscular system of hindlimb-suspended animals, it is suggested that the unloading due to hindlimb suspension alters afferent signaling and feedback information from intramuscular receptors to the cerebral cortex due to modifications in the reflex organization of hindlimb muscle groups. We propose that the reduction in immunoreactivity of local circuit GABAergic neurons and terminals is an expression of changes in their modulatory activity to compensate for the alterations in the afferent information.

  7. MUNICIPAL WASTE COMBUSTION ASSESSMENT: WASTE CO- FIRING

    EPA Science Inventory

    The report is an overview of waste co-firing and auxiliary fuel fired technology and identifies the extent to which co-firing and auxiliary fuel firing are practised. Waste co-firing is defined as the combustion of wastes (e. g., sewage sludge, medical waste, wood waste, and agri...

  8. The roles of direct input of energy from the solar wind and unloading of stored magnetotail energy in driving magnetospheric substorms

    NASA Technical Reports Server (NTRS)

    Rostoker, G.; Akasofu, S. I.; Baumjohann, W.; Kamide, Y.; Mcpherron, R. L.

    1987-01-01

    The contributions to the substorm expansive phase of direct energy input from the solar wind and from energy stored in the magnetotail which is released in an unpredictable manner are considered. Two physical processes for the dispensation of the energy input from the solar wind are identified: (1) a driven process in which energy supplied from the solar wind is directly dissipated in the ionosphere; and (2) a loading-unloading process in which energy from the solar wind is first stored in the magnetotail and then is suddenly released to be deposited in the ionosphere. The pattern of substorm development in response to changes in the interplanetary medium has been elucidated for a canonical isolated substorm.

  9. Effects of hindlimb unloading and ionizing radiation on skeletal muscle resistance artery vasodilation and its relation to cancellous bone in mice.

    PubMed

    Prisby, Rhonda D; Alwood, Joshua S; Behnke, Brad J; Stabley, John N; McCullough, Danielle J; Ghosh, Payal; Globus, Ruth K; Delp, Michael D

    2016-01-15

    Spaceflight has profound effects on vascular function as a result of weightlessness that may be further compounded by radiation exposure. The purpose of the present study was to assess the individual and combined effects of hindlimb unloading (HU) and radiation (Rad) on vasodilator responses in the skeletal muscle vasculature. Adult male C57BL/6J mice were randomized to one of four groups: control (Con), HU (tail suspension for 15 days), Rad (200 cGy of (137)Cs), and HU-Rad (15-day tail suspension and 200 cGy of (137)Cs). Endothelium-dependent vasodilation of gastrocnemius feed arteries was assessed in vitro using acetylcholine (ACh, 10(-9)-10(-4) M) and inhibitors of nitric oxide synthase (NOS) and cyclooxygenase (COX). Endothelium-independent vasodilation was assessed using Dea-NONOate (10(-9)-10(-4) M). Endothelium-dependent and -independent vasodilator responses were impaired relative to Con responses in all treatment groups; however, there was no further impairment from the combination of treatments (HU-Rad) relative to that in the HU and Rad groups. The NOS-mediated contribution to endothelium-dependent vasodilation was depressed with HU and Rad. This impairment in NOS signaling may have been partially compensated for by an enhancement of PGI2-mediated dilation. Changes in endothelium-dependent vasodilation were also associated with decrements in trabecular bone volume in the proximal tibia metaphysis. These data demonstrate that the simulated space environment (i.e., radiation exposure and unloading of muscle and bone) significantly impairs skeletal muscle artery vasodilation, mediated through endothelium-dependent reductions in NOS signaling and decrements in vascular smooth muscle cell responsiveness to NO. PMID:26472865

  10. Differential skeletal responses of hindlimb unloaded rats on a vitamin D-deficient diet to 1,25-dihydroxyvitamin D3 and its analog, seocalcitol (EB1089)

    NASA Technical Reports Server (NTRS)

    Narayanan, Ramesh; Allen, Matthew R.; Gaddy, Dana; Bloomfield, Susan A.; Smith, Carolyn L.; Weigel, Nancy L.

    2004-01-01

    Conditions of disuse in bed rest patients, as well as microgravity experienced by astronauts are accompanied by reduced mechanical loading, reduced calcium absorption, and lower serum levels of 1,25(OH)2D3 (1,25-D), the active metabolite of vitamin D, all contributing to bone loss. To determine whether 1,25-D or a less calcemic analog, Seocalcitol or EB1089 (1 alpha,25-dihydroxy-22,24-diene-24,26,27-trihomovitamin D3) can alleviate bone loss in a rat hindlimb unloading model of disuse osteopenia, mature male rats originally on a vitamin D replete diet containing 1.01% calcium were transferred to a vitamin D-deficient diet containing 0.48% calcium and then tail suspended and treated for 28 days with vehicle, 0.05 microg/kg 1,25-D, or 0.05 microg/kg EB1089. The vitamin D-deficient diet caused a substantial decrease in bone mineral density (-8%), which may be compounded by hindlimb unloading (-10%). Exogenous 1,25-D not only prevented the bone loss but also increased the bone mineral density to greater than the baseline level (+7%). EB1089 was less effective in preventing bone loss. Analysis of site and cell-specific effects of 1,25-D and EB1089 revealed that 1,25-D was more active than EB1089 in the intestine, the site of calcium absorption, and in inducing osteoclastogenesis and bone resorption whereas EB1089 was more effective in inducing osteoblast differentiation. These studies suggest that elevating circulating 1,25-D levels presumably increasing calcium absorption can counteract bone loss induced by disuse or microgravity with its associated reductions in circulating 1,25-D and decreased calcium absorption.

  11. Inhibition of Osteocyte Apoptosis Prevents the Increase in Osteocytic Receptor Activator of Nuclear Factor κB Ligand (RANKL) but Does Not Stop Bone Resorption or the Loss of Bone Induced by Unloading*

    PubMed Central

    Plotkin, Lilian I.; Gortazar, Arancha R.; Davis, Hannah M.; Condon, Keith W.; Gabilondo, Hugo; Maycas, Marta; Allen, Matthew R.; Bellido, Teresita

    2015-01-01

    Apoptosis of osteocytes and osteoblasts precedes bone resorption and bone loss with reduced mechanical stimulation, and receptor activator of NF-κB ligand (RANKL) expression is increased with unloading in mice. Because osteocytes are major RANKL producers, we hypothesized that apoptotic osteocytes signal to neighboring osteocytes to increase RANKL expression, which, in turn, increases osteoclastogenesis and bone resorption. The traditional bisphosphonate (BP) alendronate (Aln) or IG9402, a BP analog that does not inhibit resorption, prevented the increase in osteocyte apoptosis and osteocytic RANKL expression. The BPs also inhibited osteoblast apoptosis but did not prevent the increase in osteoblastic RANKL. Unloaded mice exhibited high serum levels of the bone resorption marker C-telopeptide fragments of type I collagen (CTX), elevated osteoclastogenesis, and increased osteoclasts in bone. Aln, but not IG9402, prevented all of these effects. In addition, Aln prevented the reduction in spinal and femoral bone mineral density, spinal bone volume/tissue volume, trabecular thickness, mechanical strength, and material strength induced by unloading. Although IG9402 did not prevent the loss of bone mass, it partially prevented the loss of strength, suggesting a contribution of osteocyte viability to strength independent of bone mass. These results demonstrate that osteocyte apoptosis leads to increased osteocytic RANKL. However, blockade of these events is not sufficient to restrain osteoclast formation, inhibit resorption, or stop bone loss induced by skeletal unloading. PMID:26085098

  12. Dairy Wastes.

    ERIC Educational Resources Information Center

    Pico, Richard F.

    1978-01-01

    Presents a literature review of wastes from the dairy industry covering publications of 1976-77. This review covers: (1) government regulations; (2) ion-plant control of dairy effluents; (3) dairy effluent treatment methods; and (4) research on dairy effluents. A list of 26 references is also presented. (HM)

  13. Hanford Site annual dangerous waste report: Volume 1, Part 1, Generator dangerous waste report, dangerous waste

    SciTech Connect

    1994-12-31

    This report contains information on hazardous wastes at the Hanford Site. Information consists of shipment date, physical state, chemical nature, waste description, waste number, weight, and waste designation.

  14. Waste remediation

    SciTech Connect

    Halas, Nancy J.; Nordlander, Peter; Neumann, Oara

    2015-12-29

    A system including a steam generation system and a chamber. The steam generation system includes a complex and the steam generation system is configured to receive water, concentrate electromagnetic (EM) radiation received from an EM radiation source, apply the EM radiation to the complex, where the complex absorbs the EM radiation to generate heat, and transform, using the heat generated by the complex, the water to steam. The chamber is configured to receive the steam and an object, wherein the object is of medical waste, medical equipment, fabric, and fecal matter.

  15. Central Waste Complex (CWC) Waste Analysis Plan

    SciTech Connect

    ELLEFSON, M.D.

    1999-12-01

    The purpose of this waste analysis plan (WAP) is to document the waste acceptance process, sampling methodologies, analytical techniques, and overall processes that are undertaken for waste accepted for storage at the Central Waste Complex (CWC), which is located in the 200 West Area of the Hanford Facility, Richland, Washington. Because dangerous waste does not include the source, special nuclear, and by-product material components of mixed waste, radionuclides are not within the scope of this documentation. The information on radionuclides is provided only for general knowledge.

  16. The effect of different ranges of motion on local dynamic stability of the elbow during unloaded repetitive flexion-extension movements.

    PubMed

    Gsell, Kelsey Y; Beaudette, Shawn M; Graham, Ryan B; Brown, Stephen H M

    2015-08-01

    Local dynamic stability (LDS) of movement is controlled primarily by active muscles, and is known to be influenced by factors such as movement speed and inertial load. Other factors such as muscle length, the length of the target trajectory, and the resistance of passive tissues through ranges of motion (ROM) may also influence LDS. This study was designed to examine the effect of ROM, which impacts each of the aforementioned factors, on LDS of the elbow. 16 participants performed 30 unloaded, repetitive, flexion-extension movements of the elbow with varying (1) angular displacement magnitudes: 40° and 80°; (2) locations of ROM: mid-range, flexion end-range, extension end-range; and (3) rotated positions of the forearm: pronated and supinated. LDS was calculated using a finite time Lyapunov analysis of angular elbow flexion-extension kinematic data. EMG-based muscle activation and co-contraction data were also examined for possible mechanisms of stabilization. Results showed no changes in LDS with any movement condition; however, there were significant effects on muscle activation with ROM location and forearm rotated position. This suggests that a consistent level of LDS of the elbow through varying ROMs is maintained, at least in part, by the active control of the elbow flexor and extensor muscles. PMID:26048713

  17. The Cardiomyopathy Lamin A/C D192G Mutation Disrupts Whole-Cell Biomechanics in Cardiomyocytes as Measured by Atomic Force Microscopy Loading-Unloading Curve Analysis

    PubMed Central

    Lanzicher, Thomas; Martinelli, Valentina; Puzzi, Luca; Del Favero, Giorgia; Codan, Barbara; Long, Carlin S.; Mestroni, Luisa; Taylor, Matthew R. G.; Sbaizero, Orfeo

    2015-01-01

    Atomic force microscopy (AFM) cell loading/unloading curves were used to provide comprehensive insights into biomechanical behavior of cardiomyocytes carrying the lamin A/C (LMNA) D192G mutation known to cause defective nuclear wall, myopathy and severe cardiomyopathy. Our results suggested that the LMNA D192G mutation increased maximum nuclear deformation load, nuclear stiffness and fragility as compared to controls. Furthermore, there seems to be a connection between this lamin nuclear mutation and cell adhesion behavior since LMNA D192G cardiomyocytes displayed loss of AFM probe-to-cell membrane adhesion. We believe that this loss of adhesion involves the cytoskeletal architecture since our microscopic analyses highlighted that mutant LMNA may also lead to a morphological alteration in the cytoskeleton. Furthermore, chemical disruption of the actin cytoskeleton by cytochalasin D in control cardiomyocytes mirrored the alterations in the mechanical properties seen in mutant cells, suggesting a defect in the connection between the nucleoskeleton, cytoskeleton and cell adhesion molecules in cells expressing the mutant protein. These data add to our understanding of potential mechanisms responsible for this fatal cardiomyopathy, and show that the biomechanical effects of mutant lamin extend beyond nuclear mechanics to include interference of whole-cell biomechanical properties. PMID:26323789

  18. Short-term variability in respiratory impedance and effect of deep breath in asthmatic and healthy subjects with airway smooth muscle activation and unloading.

    PubMed

    Gobbi, Alessandro; Pellegrino, Riccardo; Gulotta, Carlo; Antonelli, Andrea; Pompilio, Pasquale; Crimi, Claudia; Torchio, Roberto; Dutto, Luca; Parola, Paolo; Dellacà, Raffaele L; Brusasco, Vito

    2013-09-01

    Inspiratory resistance (RINSP) and reactance (XINSP) were measured for 7 min at 5 Hz in 10 subjects with mild asymptomatic asthma and 9 healthy subjects to assess the effects of airway smooth muscle (ASM) activation by methacholine (MCh) and unloading by chest wall strapping (CWS) on the variability of lung function and the effects of deep inspiration (DI). Subjects were studied at control conditions, after MCh, with CWS, and after MCh with CWS. In all experimental conditions XINSP was significantly more negative in subjects with asthma than in healthy subjects, suggesting greater inhomogeneity in the former. However, the variability in both RINSP and XINSP was increased by either ASM activation or CWS, without significant difference between groups. DI significantly reversed MCh-induced changes in RINSP both in subjects with asthma and healthy subjects, but XINSP in the former only. This effect was impaired by CWS more in subjects with asthma than in healthy subjects. The velocity of RINSP and XINSP recovery after DI was faster in subjects with asthma than healthy subjects. In conclusion, these results support the opinion that the short-term variability in respiratory impedance is related to ASM tone or operating length, rather than to the disease. Nevertheless, ASM in individuals with asthma differs from that in healthy individuals in an increased velocity of shortening and a reduced sensitivity to mechanical stress when strain is reduced. PMID:23766502

  19. Thermodynamic analysis of compact formation; compaction, unloading, and ejection. I. Design and development of a compaction calorimeter and mechanical and thermal energy determinations of powder compaction.

    PubMed

    DeCrosta, M T; Schwartz, J B; Wigent, R J; Marshall, K

    2000-03-30

    The aim of this investigation was to determine and evaluate the thermodynamic properties, i.e. heat, work, and internal energy change, of the compaction process by developing a 'Compaction Calorimeter'. Compaction of common excipients and acetaminophen was performed by a double-ended, constant-strain tableting waveform utilizing an instrumented 'Compaction Simulator.' A constant-strain waveform provides a specific quantity of applied compaction work. A calorimeter, built around the dies, used a metal oxide thermistor to measure the temperature of the system. A resolution of 0.0001 degrees C with a sampling time of 5 s was used to monitor the temperature. An aluminum die within a plastic insulating die, in conjunction with fiberglass punches, comprised the calorimeter. Mechanical (work) and thermal (heat) calibrations of the elastic punch deformation were performed. An energy correction method was outlined to account for system heat effects and mechanical work of the punches. Compaction simulator transducers measured upper and lower punch forces and displacements. Measurements of the effective heat capacity of the samples were performed utilizing an electrical resistance heater. Specific heat capacities of the samples were determined by differential scanning calorimetry. The calibration techniques were utilized to determine heat, work, and the change in internal energies of powder compaction. Future publications will address the thermodynamic evaluation of the tablet sub-processes of unloading and ejection. PMID:10722955

  20. ORD WASTE RESEARCH STRATEGY

    EPA Science Inventory

    The "Waste Research Strategy" covers research necessary to support both the proper management of solid and hazardous wastes and the effective remediation of contaminated waste sites.This research includes improving the assessment of existing environmental risks,...

  1. WASTE RESEARCH STRATEGY

    EPA Science Inventory

    The Waste Research Strategy covers research necessary to support both the proper management of solid and hazardous wastes and the effective remediation of contaminated waste sites. This research includes improving the assessment of existing environmental risks, as well as develop...

  2. Three Weeks of Murine Hindlimb Unloading Induces Shifts from B to T and from Th to Tc Splenic Lymphocytes in Absence of Stress and Differentially Reduces Cell-Specific Mitogenic Responses

    PubMed Central

    Gaignier, Fanny; Schenten, Véronique; De Carvalho Bittencourt, Marcelo; Gauquelin-Koch, Guillemette

    2014-01-01

    Extended space missions are known to induce stress and immune dysregulation. Hindlimb unloading is a ground-based model used to reproduce most spaceflight conditions. The aim of this study was to better characterize the consequences of prolonged exposure to hindlimb unloading on murine splenic lymphocyte sub-populations. To ensure that the observed changes were not due to tail restraint but to the antiorthostatic position, three groups of mice were used: control (C), orthostatic restrained (R) and hindlimb unloaded (HU). After 21 days of exposure, no difference in serum corticosterone levels nor in thymus and spleen weights were observed between HU mice and their counterparts, revealing a low state of stress. Interestingly, flow cytometric analyses showed that B cells were drastically reduced in HU mouse spleens by 59% and, while the T cells number did not change, the Th/Tc ratio was decreased. Finally, the use of a fluorescent dye monitoring lymphoproliferation demonstrated that lymphocyte response to mitogen was reduced in Th and Tc populations and to a greater extent in B cells. Thus, we showed for the first time that, even if restraint has its own effects on the animals and their splenic lymphocytes, the prolonged antiorthostatic position leads, despite the absence of stress, to an inversion of the B/T ratio in the spleen. Furthermore, the lymphoproliferative response was impaired with a strong impact on B cells. Altogether, these results suggest that B cells are more affected by hindlimb unloading than T cells which may explain the high susceptibility to pathogens, such as gram-negative bacteria, described in animal models and astronauts. PMID:24664102

  3. The protective effects of Chinese herb-Taikong Yangxin Prescription on the atrophic remodeling of cardiac muscle in rats induced by hindlimb unloading through activating Akt/GSK-3beta signaling pathway

    NASA Astrophysics Data System (ADS)

    Ming, Yuan; Min, Yuan; Jianfeng, Zhang; Zhili, Li; Huijuan, Wang; Desheng, Wang; Yinghui, Li; Yongzhi, Li; Shizhong, Jiang

    Objective To test the hypothesis that traditional Chinese herb-TaiKong Yangxin Prescrip-tion can activate the Akt/GSK-3β signaling pathway and alleviate the atrophic remodeling of cardiac muscle in rats induced by hindlimb unloading. Methods The physiological effects of simulated microgravity was induced by 7d hindlimb unloading in rats. TaiKong Yangxin Pre-scription was given daily by gastric irrigation as countermeasure against effects of simulated microgravity. The frozen sections of left ventricular cardiac muscles were stained by FITC la-beled lectin and visualized by laser scanning confocal microscopy, the cross section areas(CSA) of cardiomyocytes were calculated by IPP6.0 Image software. The protein expression of TnI, phosphorylation level of Akt and GSK-3β were measured by Western blot. Results Simulated microgravity decreased the CSA of cardiomyocytes and protein expression of TnI in left ven-tricular cardiac muscles, inhibited the phosphorylation level of Akt at serine 473 and GSK-3β at serine 9. The traditional Chinese herb-TaiKong Yangxin Prescription alleviated the atrophic remodeling of cardiac muscles, reversed the declined protein expression of TnI and phosphoryla-tion levels of Akt at serine 473 and GSK-3β at serine 9 in hindlimb-unloading rats. Conclusion The traditional Chinese herb-TaiKong Yangxin Prescription has significant countermeasure effects on the atrophic remodeling of cardiac muscle induced by hindlimb unloading in rats, in which activating Akt/GSK-3β signaling pathway plays an important role.(Funded by Advanced space medico-engineering research project of China, grant NO. 2005SY5206005 and SJ200801)

  4. Chemical Waste and Allied Products.

    PubMed

    Hung, Yung-Tse; Aziz, Hamidi Abdul; Ramli, Siti Fatihah; Yeh, Ruth Yu-Li; Liu, Lian-Huey; Huhnke, Christopher Robert

    2016-10-01

    This review of literature published in 2015 focuses on waste related to chemical and allied products. The topics cover the waste management, physicochemical treatment, aerobic granular, aerobic waste treatment, anaerobic granular, anaerobic waste treatment, chemical waste, chemical wastewater, fertilizer waste, fertilizer wastewater, pesticide wastewater, pharmaceutical wastewater, ozonation. cosmetics waste, groundwater remediation, nutrient removal, nitrification denitrification, membrane biological reactor, and pesticide waste. PMID:27620094

  5. Evaluating the effect of vehicle impoundment policy on illegal construction and demolition waste dumping: Israel as a case study.

    PubMed

    Seror, Nissim; Hareli, Shlomo; Portnov, Boris A

    2014-08-01

    Construction and demolition (C&D) waste dumped alongside roads and in open areas is a major source of soil and underground water pollution. Since 2006, Israeli ministry for environmental protection enacted a policy of vehicle impoundment (VI) according to which track drivers caught while dumping C&D waste illegally have their vehicles impounded. The present study attempted to determine whether the VI policy was effective in increasing the waste hauling to authorized landfill sites, thus limiting the number of illegal unloads of C&D waste at unauthorized landfill sites and in open areas. During the study, changes in the ratio between the monthly amount of C&D waste brought to authorized landfills sites and the estimated total amount of C&D waste generated in different administrative districts of Israel were examined, before and after the enactment of the 2006 VI policy. Short questionnaires were also distributed among local track drivers in order to determine the degree of awareness about the policy in question and estimate its deterrence effects. According to the study's results, in the district of Haifa, in which the VI policy was stringently enacted, the ratio between C&D waste, dumped in authorized landfill sites, and the total amount of generated C&D waste, increased, on the average, from 20% in January 2004 to 35% in October 2009, with the effect attributed to the number of vehicle impoundments being highly statistically significant (t=2.324; p<0.05). By contrast, in the Jerusalem and Southern districts, in which the VI policy was less stringently enforced, the effect of VI on the above ratio was found to be insignificant (p>0.1). The analysis of the questionnaires, distributed among the local truck drivers further indicated that the changes observed in the district of Haifa are not coincident and appeared to be linked to the VI policy's enactment. In particular, 62% of the truck drivers, participated in the survey, were aware of the policy and 47% of them

  6. Hanford Site annual dangerous waste report: Volume 3, Part 1, Waste Management Facility report, dangerous waste

    SciTech Connect

    1994-12-31

    This report contains information on hazardous wastes at the Hanford Site. Information consists of shipment date, physical state, chemical nature, waste description, handling method and containment vessel, waste number, waste designation, and amount of waste.

  7. Hanford Site annual dangerous waste report: Volume 2, Generator dangerous waste report, radioactive mixed waste

    SciTech Connect

    1994-12-31

    This report contains information on radioactive mixed wastes at the Hanford Site. Information consists of shipment date, physical state, chemical nature, waste description, waste number, waste designation, weight, and waste designation.

  8. Hanford Site annual dangerous waste report: Volume 4, Waste Management Facility report, Radioactive mixed waste

    SciTech Connect

    1994-12-31

    This report contains information on radioactive mixed wastes at the Hanford Site. Information consists of shipment date, physical state, chemical nature, waste description, handling method and containment vessel, waste number, waste designation and amount of waste.

  9. Effects of High-LET Radiation Exposure and Hindlimb Unloading on Skeletal Muscle Resistance Artery Vasomotor Properties and Cancellous Bone Microarchitecture in Mice.

    PubMed

    Ghosh, Payal; Behnke, Brad J; Stabley, John N; Kilar, Cody R; Park, Yoonjung; Narayanan, Anand; Alwood, Joshua S; Shirazi-Fard, Yasaman; Schreurs, Ann-Sofie; Globus, Ruth K; Delp, Michael D

    2016-03-01

    Weightlessness during spaceflight leads to functional changes in resistance arteries and loss of cancellous bone, which may be potentiated by radiation exposure. The purpose of this study was to assess the effects of hindlimb unloading (HU) and total-body irradiation (TBI) on the vasomotor responses of skeletal muscle arteries. Male C57BL/6 mice were assigned to control, HU (13-16 days), TBI (1 Gy (56)Fe, 600 MeV, 10 cGy/min) and HU-TBI groups. Gastrocnemius muscle feed arteries were isolated for in vitro study. Endothelium-dependent (acetylcholine) and -independent (Dea-NONOate) vasodilator and vasoconstrictor (KCl, phenylephrine and myogenic) responses were evaluated. Arterial endothelial nitric oxide synthase (eNOS), superoxide dismutase-1 (SOD-1) and xanthine oxidase (XO) protein content and tibial cancellous bone microarchitecture were quantified. Endothelium-dependent and -independent vasodilator responses were impaired in all groups relative to control, and acetylcholine-induced vasodilation was lower in the HU-TBI group relative to that in the HU and TBI groups. Reductions in endothelium-dependent vasodilation correlated with a lower cancellous bone volume fraction. Nitric oxide synthase inhibition abolished all group differences in endothelium-dependent vasodilation. HU and HU-TBI resulted in decreases in eNOS protein levels, while TBI and HU-TBI produced lower SOD-1 and higher XO protein content. Vasoconstrictor responses were not altered. Reductions in NO bioavailability (eNOS), lower anti-oxidant capacity (SOD-1) and higher pro-oxidant capacity (XO) may contribute to the deficits in NOS signaling in skeletal muscle resistance arteries. These findings suggest that the combination of insults experienced in spaceflight leads to impairment of vasodilator function in resistance arteries that is mediated through deficits in NOS signaling. PMID:26930379

  10. [The Activation of Interlimb Interactions Increase the Motor Output in Legs in Healthy Subjects under the Conditions of Arm and Leg Unloading].

    PubMed

    Selionov, V A; Solopova, I A; Zhvansky, D S

    2016-01-01

    We studied the effect of arm movements and movements of separate arm joints on the electrophysiological and kinematic characteristics of voluntary and vibration-triggered stepping-like leg movements under the conditions of horizontal support of upper and lower limbs. The horizontal support of arms provided a significantly increase in the rate of activation of locomotor automatism by non-invasive impact on tonic sensory inputs. The addition of active arm movements during involuntary rhytmic stepping-like leg movements led to an increase in EMG activity of hip muscles and was accompanied by an increase in the amplitude of hip and shin movements. Passive arm movements had the same effect on induced leg movements. The movement of the shoulder joints led to an increase in the activity of hip muscles and an increase in the amplitude of movements of the knee and hip joints. At the same time, the movement of forearms. and wrists had similar facilitating effect on electrophysiological and kinematic characteristics of rhytmic stepping-like movements, but influenced the distal segments of legs to a greater extent. Under the conditions of sub-threshold vibration of leg muscles, voluntary arm movements led to the activation of involuntary rhytmic stepping movements. During voluntary leg movements, the addition of arm movements had a significantly smaller impact on the parameters of rhytmic stepping than during involuntary leg movements. Thus, the simultaneous movements of upper and lower limbs are an effective method of activation of neural networks connecting the rhythm generators of arms and legs. Under the conditions of arm and leg unloading, the interactions between the cervical and lumbosacral segments of the spinal cord seem to play the major role in the impact of arm movements on the patterns of leg movements. The described methods of activation of interlimb interactions can be used in the rehabilitation of post-stroke patients and patients with spinal cord injuries

  11. Joint unloading implant modifies subchondral bone trabecular structure in medial knee osteoarthritis: 2-year outcomes of a pilot study using fractal signature analysis

    PubMed Central

    Miller, Larry E; Sode, Miki; Fuerst, Thomas; Block, Jon E

    2015-01-01

    Background Knee osteoarthritis (OA) is largely attributable to chronic excessive and aberrant joint loading. The purpose of this pilot study was to quantify radiographic changes in subchondral bone after treatment with a minimally invasive joint unloading implant (KineSpring® Knee Implant System). Methods Nine patients with unilateral medial knee OA resistant to nonsurgical therapy were treated with the KineSpring System and followed for 2 years. Main outcomes included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function, and stiffness subscores and independent core laboratory determinations of joint space width and fractal signature of the tibial cortex. Results WOMAC scores, on average, improved by 92% for pain, 91% for function, and 79% for stiffness over the 2-year follow-up period. Joint space width in the medial compartment of the treated knee significantly increased from 0.9 mm at baseline to 3.1 mm at 2 years; joint space width in the medial compartment of the untreated knee was unchanged. Fractal signatures of the vertically oriented trabeculae in the medial compartment decreased by 2.8% in the treated knee and increased by 2.1% in the untreated knee over 2 years. No statistically significant fractal signature changes were observed in the horizontally oriented trabeculae in the medial compartment or in the horizontal or vertical trabeculae of the lateral compartment in the treated knee. Conclusion Preliminary evidence suggests that the KineSpring System may modify knee OA disease progression by increasing joint space width and improving subchondral bone trabecular integrity, thereby reducing pain and improving joint function. PMID:25670891

  12. Self-assembled biotransesterified cyclodextrins as potential Artemisinin nanocarriers. II: In vitro behavior toward the immune system and in vivo biodistribution assessment of unloaded nanoparticles.

    PubMed

    Yaméogo, Josias B G; Gèze, Annabelle; Choisnard, Luc; Putaux, Jean-Luc; Mazet, Roseline; Passirani, Catherine; Keramidas, Michelle; Coll, Jean-Luc; Lautram, Nolwenn; Bejaud, Jérôme; Semdé, Rasmané; Wouessidjewe, Denis

    2014-11-01

    In a previous study, we reported on the formulation of Artemisinin-loaded surface-decorated nanoparticles (nanospheres and nanoreservoirs) by co-nanoprecipitation of PEG derivatives (PEG1500 and PEG4000-stearate, polysorbate 80) and biosynthesized γ-CD fatty esters. In the present study, the co-nanoprecipitation was extended to the use of a PEGylated phospholipid, namely DMPE-PEG2000. As our goal was to prepare long-circulating nanocarriers for further systemic delivery of Artemisinin (ART), here, we have investigated, on the one hand, the in vitro behavior of these surface-modified γ-CD-C10 particles toward the immune system (complement activation and macrophage uptake assays) and, on the other hand, their biodistribution features in mice. These experiments showed that the in vitro plasma protein adsorption and phagocytosis by macrophage cells triggered by γ-CD-C10 nanoparticles were significantly reduced when their surface was decorated with amphiphilic PEGylated molecules, in particular PEG1500-stearate, DMPE-mPEG2000 or polysorbate 80. The prolonged blood circulation time assessed by fluorescence imaging was demonstrated for unloaded γ-CD-C10-based nanospheres and nanoreservoir particles containing DMPE-PEG2000 and polysorbate80, respectively. These nanoparticles also proved to be non-hemolytic at the concentration range used in vivo. Within the limits of the conducted experiments, the co-nanoprecipitation technique may be considered as an alternative for surface modification of amphiphilic CD-based drug delivery systems and may be applied to the systemic delivery of ART. PMID:25204521

  13. Functional characterization and expression analysis of cucumber (Cucumis sativus L.) hexose transporters, involving carbohydrate partitioning and phloem unloading in sink tissues.

    PubMed

    Cheng, Jin-Tao; Li, Xiang; Yao, Feng-Zhen; Shan, Nan; Li, Ya-Hui; Zhang, Zhen-Xian; Sui, Xiao-Lei

    2015-08-01

    Many hexose transporters (HTs) have been reported to play roles in sucrose-transporting plants. However, little information about roles of HTs in RFOs (raffinose family oligosaccharides)-transporting plants has been reported. Here, three hexose transporters (CsHT2, CsHT3, and CsHT4) were cloned from Cucumis sativus L. Heterologous expression in yeast demonstrated that CsHT3 transported glucose, galactose and mannose, with a K(m) of 131.9 μM for glucose, and CsHT4 only transported galactose, while CsHT2 was non-functional. Both CsHT3 and CsHT4 were targeted to the plasma membrane of cucumber protoplasts. Spatio-temporal expression indicated that transcript level of CsHT3 was much higher than that of CsHT2 and CsHT4 in most tissues, especially in peduncles and fruit tissues containing vascular bundles. GUS staining of CsHT3-promoter-β-glucuronidase (GUS) transgenic Arabidopsis plants revealed CsHT3 expression in tissues with high metabolic turnover, suggesting that CsHT3 is involved in sugar competition among different sink organs during plant development. The transcript levels of CsHT3 and cell wall invertase genes increased in peduncles and fruit tissues along with cucumber fruit enlargement, and CsHT3 localized to phloem tissues by immunohistochemical localization; These results suggest that CsHT3 probably plays an important role in apoplastic phloem unloading of cucumber fruit. PMID:26089151

  14. Waste management system

    NASA Technical Reports Server (NTRS)

    Sauer, R. L.; Jorgensen, G. K.

    1975-01-01

    The function of the waste management system was to control the disposition of solid and liquid wastes and waste stowage gases. The waste management system consisting of a urine subsystem and a fecal subsystem is described in detail and its overall performance is evaluated. Recommendations for improvement are given.

  15. PUREX Organic Waste Solidification

    SciTech Connect

    Langton, C.A.

    2002-12-12

    The objectives of this study were to evaluate solidification/stabilization as an alternative treatment technology for the organic phase of the SRS spent PUREX waste using simulated waste, and to evaluate waste forms prepared with actual spent organic PUREX waste for regulatory classification.

  16. Infectious waste feed system

    DOEpatents

    Coulthard, E. James

    1994-01-01

    An infectious waste feed system for comminuting infectious waste and feeding the comminuted waste to a combustor automatically without the need for human intervention. The system includes a receptacle for accepting waste materials. Preferably, the receptacle includes a first and second compartment and a means for sealing the first and second compartments from the atmosphere. A shredder is disposed to comminute waste materials accepted in the receptacle to a predetermined size. A trough is disposed to receive the comminuted waste materials from the shredder. A feeding means is disposed within the trough and is movable in a first and second direction for feeding the comminuted waste materials to a combustor.

  17. Waste Package Lifting Calculation

    SciTech Connect

    H. Marr

    2000-05-11

    The objective of this calculation is to evaluate the structural response of the waste package during the horizontal and vertical lifting operations in order to support the waste package lifting feature design. The scope of this calculation includes the evaluation of the 21 PWR UCF (pressurized water reactor uncanistered fuel) waste package, naval waste package, 5 DHLW/DOE SNF (defense high-level waste/Department of Energy spent nuclear fuel)--short waste package, and 44 BWR (boiling water reactor) UCF waste package. Procedure AP-3.12Q, Revision 0, ICN 0, calculations, is used to develop and document this calculation.

  18. The solid waste dilemma

    USGS Publications Warehouse

    Amey, E.B.; Russell, J.A.; Hurdelbrink, R.J.

    1996-01-01

    In 1976, the U.S. Congress enacted the Resource Conservation and Recovery Act (RCRA) to further address the problem of increasing industrial and municipal waste. The main objectives of RCRA were to responsibly manage hazardous and solid waste and to procure materials made from recovered wastes. To fulfill these objectives, four main programs of waste management were developed. These programs were defined under Subtitle C, the Hazardous Waste Program; Subtitle D, the Solid Waste Program; Subtitle I, the Underground Storage Tank Program; and Subtitle J, the Medical Waste Program. Subtitle D illustrates the solid waste dilemma occurring in the United States. Under this program, states are encouraged to develop and implement their own waste management plans. These plans include the promotion of recycling solid wastes and the closing and upgrading of all environmentally unsound dumps. ?? 1996 International Association for Mathematical Geology.

  19. Radioactive mixed waste disposal

    SciTech Connect

    Jasen, W.G.; Erpenbeck, E.G.

    1993-02-01

    Various types of waste have been generated during the 50-year history of the Hanford Site. Regulatory changes in the last 20 years have provided the emphasis for better management of these wastes. Interpretations of the Atomic Energy Act of 1954 (AEA), the Resource Conservation and Recovery Act of 1976 (RCRA), and the Hazardous and Solid Waste Amendments (HSWA) have led to the definition of radioactive mixed wastes (RMW). The radioactive and hazardous properties of these wastes have resulted in the initiation of special projects for the management of these wastes. Other solid wastes at the Hanford Site include low-level wastes, transuranic (TRU), and nonradioactive hazardous wastes. This paper describes a system for the treatment, storage, and disposal (TSD) of solid radioactive waste.

  20. Understanding radioactive waste

    SciTech Connect

    Murray, R.L.

    1981-12-01

    This document contains information on all aspects of radioactive wastes. Facts are presented about radioactive wastes simply, clearly and in an unbiased manner which makes the information readily accessible to the interested public. The contents are as follows: questions and concerns about wastes; atoms and chemistry; radioactivity; kinds of radiation; biological effects of radiation; radiation standards and protection; fission and fission products; the Manhattan Project; defense and development; uses of isotopes and radiation; classification of wastes; spent fuels from nuclear reactors; storage of spent fuel; reprocessing, recycling, and resources; uranium mill tailings; low-level wastes; transportation; methods of handling high-level nuclear wastes; project salt vault; multiple barrier approach; research on waste isolation; legal requiremnts; the national waste management program; societal aspects of radioactive wastes; perspectives; glossary; appendix A (scientific American articles); appendix B (reference material on wastes). (ATT)

  1. Nuclear waste solidification

    DOEpatents

    Bjorklund, William J.

    1977-01-01

    High level liquid waste solidification is achieved on a continuous basis by atomizing the liquid waste and introducing the atomized liquid waste into a reaction chamber including a fluidized, heated inert bed to effect calcination of the atomized waste and removal of the calcined waste by overflow removal and by attrition and elutriation from the reaction chamber, and feeding additional inert bed particles to the fluidized bed to maintain the inert bed composition.

  2. Radium bearing waste disposal

    SciTech Connect

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-07-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach.

  3. Waste destruction by plasma

    NASA Astrophysics Data System (ADS)

    Cretenot, Didier; Vanrenterghem, Jacques; Labrot, Maxime; Pineau, Didier

    The use of arc plasma for waste destruction is addressed. Types of treatable waste, processes for liquid and solid or pasty wastes, and the present state of these techniques in France are described. The efficiency of arc plasma technology in the destruction of liquid organochlorinated waste compounds in commercial size units, particularly mobile units, is demonstrated. Many trials with solid waste demonstrate that plasmas are a highly efficient solution.

  4. Waste Inspection Tomography (WIT)

    SciTech Connect

    Bernardi, R.T.; Han, Kyung S.

    1994-11-01

    This article describes the Waste Inspection Tomography Program. The program provides an inspection system that offers the nuclear waste evaluator a unique combination of tools for regulatory-driven characterization of low-level waste, transuranic waste, and mixed waste drums. WIT provides nondestructive, noninvasive and environmentally safe inspections using x-ray and gamma ray technologies with reasonable cost and throughput. included are background information; project description; and results. 11 figs.

  5. Industrial waste pollution

    NASA Technical Reports Server (NTRS)

    Jensen, L. D.

    1972-01-01

    The characteristics and effects of industrial waste pollution in the Chesapeake Bay are discussed. The sources of inorganic and organic pollution entering the bay are described. The four types of pollutants are defined as: (1) inorganic chemical wastes, (2) naturally occurring organic wastes, (3) synthetic organic wastes (exotics) and (4) thermal effluents. The ecological behavior of industrial wastes in the surface waters is analyzed with respect to surface film phenomena, interfacial phenomena, and benthis phenomena

  6. The Disposal of Hazardous Wastes.

    ERIC Educational Resources Information Center

    Barnhart, Benjamin J.

    1978-01-01

    The highlights of a symposium held in October, 1977 spotlight some problems and solutions. Topics include wastes from coal technologies, radioactive wastes, and industrial and agricultural wastes. (BB)

  7. Minimizing hazardous waste

    SciTech Connect

    DeClue, S.C.

    1996-06-01

    Hazardous waste minimization is a broad term often associated with pollution prevention, saving the environment or protecting Mother Earth. Some associate hazardous waste minimization with saving money. Thousands of hazardous materials are used in processes every day, but when these hazardous materials become hazardous wastes, dollars must be spent for disposal. When hazardous waste is reduced, an organization will spend less money on hazardous waste disposal. In 1993, Fort Bragg reduced its hazardous waste generation by over 100,000 pounds and spent nearly $90,000 less on hazardous waste disposal costs than in 1992. Fort Bragg generates a variety of wastes: Vehicle maintenance wastes such as antifreeze, oil, grease and solvents; helicopter maintenance wastes, including solvents, adhesives, lubricants and paints; communication operation wastes such as lithium, magnesium, mercury and nickel-cadmium batteries; chemical defense wastes detection, decontamination, and protective mask filters. The Hazardous Waste Office has the responsibility to properly identify, characterize, classify and dispose of these waste items in accordance with US Environmental Protection Agency (EPA) and US Department of Transportation (DOT) regulations.

  8. Waste catalysts for waste polymer.

    PubMed

    Salmiaton, A; Garforth, A

    2007-01-01

    Catalytic cracking of high-density polyethylene (HDPE) over fluid catalytic cracking (FCC) catalysts (1:6 ratio) was carried out using a laboratory fluidized bed reactor operating at 450 degrees C. Two fresh and two steam deactivated commercial FCC catalysts with different levels of rare earth oxide (REO) were compared as well as two used FCC catalysts (E-Cats) with different levels of metal poisoning. Also, inert microspheres (MS3) were used as a fluidizing agent to compare with thermal cracking process at BP pilot plant at Grangemouth, Scotland, which used sand as its fluidizing agent. The results of HDPE degradation in terms of yield of volatile hydrocarbon product are fresh FCC catalysts>steamed FCC catalysts approximately used FCC catalysts. The thermal cracking process using MS3 showed that at 450 degrees C, the product distribution gave 46 wt% wax, 14% hydrocarbon gases, 8% gasoline, 0.1% coke and 32% nonvolatile product. In general, the product yields from HDPE cracking showed that the level of metal contamination (nickel and vanadium) did not affect the product stream generated from polymer cracking. This study gives promising results as an alternative technique for the cracking and recycling of polymer waste. PMID:17084608

  9. Central waste processing system

    NASA Technical Reports Server (NTRS)

    Kester, F. L.

    1973-01-01

    A new concept for processing spacecraft type wastes has been evaluated. The feasibility of reacting various waste materials with steam at temperatures of 538 - 760 C in both a continuous and batch reactor with residence times from 3 to 60 seconds has been established. Essentially complete gasification is achieved. Product gases are primarily hydrogen, carbon dioxide, methane, and carbon monoxide. Water soluble synthetic wastes are readily processed in a continuous tubular reactor at concentrations up to 20 weight percent. The batch reactor is able to process wet and dry wastes at steam to waste weight ratios from 2 to 20. Feces, urine, and synthetic wastes have been successfully processed in the batch reactor.

  10. Pharmacokinetics of Acetaminophen in Hind Limbs Unloaded Mice: A Model System Simulating the Effects of Low Gravity on Astronauts in Space

    NASA Technical Reports Server (NTRS)

    Peterson, Amanda; Risin, Semyon A.; Ramesh, Govindarajan T.; Dasgupta, Amitava; Risin, Diana

    2008-01-01

    The pharmacokinetics (PK) of medications administered to astronauts could be altered by the conditions in Space. Low gravity and free floating (and associated hemodynamic changes) could affect the absorption, distribution, metabolism and excretion of the drugs. Knowledge of these alterations is essential for adjusting the dosage and the regimen of drug administration in astronauts. Acquiring of such knowledge has inherent difficulties due to limited opportunities for experimenting in Space. One of the approaches is to use model systems that simulate some of the Space conditions on Earth. In this study we used hind limbs unloaded mice (HLU) to investigate the possible changes in PK of acetaminophen, a widely used analgesic with high probability of use by astronauts. The HLU is recognized as an appropriate model for simulating the effects of low gravity on hemodynamic parameters. Mice were tail suspended (n = 24) for 24-96 hours prior to introduction of acetaminophen (150 - 300 mg/kg). The drug (in aqueous solution containing 10% ethyl alcohol by volume) was given orally by a gavage procedure and after the administration of acetaminophen mice were additionally suspended for 30 min, 1 and 2 hours. Control mice (n = 24) received the same dose of acetaminophen and were kept freely all the time. Blood specimens were obtained either from retroorbital venous sinuses or from heart. Acetaminophen concentration was measured in plasma by the fluorescent polarization immunoassay and the AxSYM analyzer (Abbott Laboratories). In control mice peak acetaminophen concentration was achieved at 30 min. By 1 hour the concentration decreased to less than 50% of the peak level and at 2 hours the drug was almost undetectable in the serum. HLU for 24 hours significantly altered the acetaminophen pharmacokinetic: at 30 min the acetaminophen concentrations were significantly (both statistically and medically significant) lower than in control mice. The concentrations also reduced less

  11. Osteocyte Apoptosis Caused by Hindlimb Unloading is Required to Trigger Osteocyte RANKL Production and Subsequent Resorption of Cortical and Trabecular Bone in Mice Femurs.

    PubMed

    Cabahug-Zuckerman, Pamela; Frikha-Benayed, Dorra; Majeska, Robert J; Tuthill, Alyssa; Yakar, Shoshana; Judex, Stefan; Schaffler, Mitchell B

    2016-07-01

    Osteocyte apoptosis is essential to activate bone remodeling in response to fatigue microdamage and estrogen withdrawal, such that apoptosis inhibition in vivo prevents the onset of osteoclastic resorption. Osteocyte apoptosis has also been spatially linked to bone resorption owing to disuse, but whether apoptosis plays a similar controlling role is unclear. We, therefore, 1) evaluated the spatial and temporal effects of disuse from hindlimb unloading (HLU) on osteocyte apoptosis, receptor activator of NF-κB ligand (RANKL) expression, bone resorption, and loss in mouse femora, and 2) tested whether osteocyte apoptosis was required to activate osteoclastic activity in cortical and trabecular bone by treating animals subjected to HLU with the pan-caspase apoptosis inhibitor, QVD (quinolyl-valyl-O-methylaspartyl-[-2,6-difluorophenoxy]-methylketone). Immunohistochemistry was used to identify apoptotic and RANKL-producing osteocytes in femoral diaphysis and distal trabecular bone, and µCT was used to determine the extent of trabecular bone loss owing to HLU. In both cortical and trabecular bone, 5 days of HLU increased osteocyte apoptosis significantly (3- and 4-fold, respectively, p < 0.05 versus Ctrl). At day 14, the apoptotic osteocyte number in femoral cortices declined to near control levels but remained elevated in trabeculae (3-fold versus Ctrl, p < 0.05). The number of osteocytes producing RANKL in both bone compartments was also significantly increased at day 5 of HLU (>1.5-fold versus Ctrl, p < 0.05) and further increased by day 14. Increases in osteocyte apoptosis and RANKL production preceded increases in bone resorption at both endocortical and trabecular surfaces. QVD completely inhibited not only the HLU-triggered increases in osteocyte apoptosis but also RANKL production and activation of bone resorption at both sites. Finally, µCT studies revealed that apoptosis inhibition completely prevented the trabecular bone loss caused by HLU. Together these

  12. Geochemistry of Miocene glass in sediments from the AND-2A Core, McMurdo Sound, Antarctica: magma petrogenesis and response to glacial unloading

    NASA Astrophysics Data System (ADS)

    Nyland, R.; Rocchi, S.; Di Vincenzo, G.; Del Carlo, P.; Tiepolo, M.; Field, B.

    2011-12-01

    Volcanic glass recovered from the AND-2A core between ~354 and 765 mbsf (~15.9-18.4 Ma) occurs as accumulations (2-50 vol.%) within sediments. Glass-rich sediments consist of muddy to fine sandstone and stratified diamictite. Glass varies in color, size, vesicularity, crystal content, angularity, and from fresh to moderately altered. The common occurrence of delicate cuspate forms and fresh glass suggest that they were introduced directly into the water as ashfall with minimal reworking. Therefore, key samples currently being dated using the 40Ar/39Ar method will likely provide important time horizons for the core. Pristine basaltic glass (MgO 3-8 wt.%) is ne-normative (5-30 wt.%) and has a restricted average SiO2 content (ca. 45.2 ± 0.8 wt.%). Variations in CaO and TiO2, positively correlated with MgO content, indicate differentiation controlled by fractionation of plagioclase, olivine, clinopyroxene and magnetite. Trace element concentrations, determined on glasses by LA-ICP-MS, are typical for alkaline volcanism of the Erebus Volcanic Province (EVP). Specifically, our data extends the known compositional range of Mt. Morning, the only known Early-Middle Miocene source in the EVP, to more mafic compositions, revealing the roots of both high alkaline (basanite to phonolite) and lower alkaline (alkali basalt to trachyte) differentiation series. Glass-rich sediments in glacimarine sequences from the AND-2A core record numerous cycles of glacial advance and retreat [1, 2]. Increases in rate, explosivity and volume of volcanism have been related to crustal loading and unloading by ice-sheets in Iceland and elsewhere. AND-2A sediments with high glass contents correspond with ice minimums and, geochemically, Ba/La and Ba/Hf ratios are correlated to intervals of ice expansion (decreasing values) and contraction (increasing values) at multiple depths. Within a single cycle, glass angularity, vesicularity, and composition also vary systematically. Results provide new

  13. Hanford Site annual dangerous waste report: Volume 1, Part 2, Generator dangerous waste report, dangerous waste

    SciTech Connect

    1994-12-31

    This report contains information on hazardous materials at the Hanford Site. Information consists of shipment date, physical state, chemical nature, waste description, waste number, weight, and waste designation.

  14. Industrial Waste Reduction Program

    SciTech Connect

    Not Available

    1991-10-24

    US industry generates over 12 billion tons of wastes each year. These wastes consist of undesirable by-products of industrial production that are discarded into our environment. Energy is an integral part of these wastes; it is found in the embodied energy of industrial feedstocks not optimally used, in the energy content of the wastes themselves, and in the energy needed to transport, treat, and dispose of wastes. Estimates of the potential energy savings from reducing industrial wastes range from three to four quadrillion Btu per year -- enough to meet the annual energy needs of 30 million American homes. This document presents a plan for the Industrial Waste Reduction Program, which has been designed to help achieve national goals for energy efficiency and waste minimization. The objective of the program is to improve the energy efficiency of industrial processes through cost-effective waste reduction. The initial program focus is on waste reduction opportunities in the production and use of chemicals, due to the significant amount of energy used in these activities and the large amounts of hazardous and toxic wastes they generate. The chemical industry will be the initial subject of a series of waste reduction opportunity assessments conducted as part of the program. Assessments of other industries and waste problems will follow.

  15. Mobile loading transuranic waste at small quantity sites in the Department of Energy complex-10523

    SciTech Connect

    Carter, Mitch; Howard, Bryan; Weyerman, Wade; Mctaggart, Jerri

    2009-01-01

    Los Alamos National Laboratory, Carlsbad Office (LANL-CO), operates mobile loading operations for all of the large and small quantity transuranic (TRU) waste sites in the Department of Energy (DOE) complex. The mobile loading team performs loading and unloading evolutions for both contact handled (CH) and remote handled (RH) waste. For small quantity sites, many of which have yet to remove their TRU waste, the mobile loading team will load shipments that will ship to Idaho National Laboratory, a centralization site, or ship directly to the Waste Isolation Pilot Plant (WIPP). For example, Argonne National Laboratory and General Electric Vallecitos Nuclear Center have certified programs for RH waste so they will ship their RH waste directly to WIPP. Many of the other sites will ship their waste to Idaho for characterization and certification. The Mobile Loading Units (MLU) contain all of the necessary equipment needed to load CH and RH waste into the appropriate shipping vessels. Sites are required to provide additional equipment, such as cranes, fork trucks, and office space. The sites are also required to provide personnel to assist in the shipping operations. Each site requires a site visit from the mobile loading team to ensure that all of the necessary site equipment, site requirements and space for shipping can be provided. The mobile loading team works diligently with site representatives to ensure that all safety and regulatory requirements are met. Once the waste is ready and shipping needs are met, the mobile loading team can be scheduled to ship the waste. The CH MLU is designed to support TRUPACT-II and HalfPACT loading activities wherever needed within the DOE complex. The team that performs the mobile loading operation has obtained national certification under DOE for TRUPACT-II and HalfPACT loading and shipment certification. The RH MLU is designed to support removable lid canister (RLC) and RH-72B cask loading activities wherever needed within the DOE

  16. Action on Hazardous Wastes.

    ERIC Educational Resources Information Center

    EPA Journal, 1979

    1979-01-01

    U.S. EPA is gearing up to investigate about 300 hazardous waste dump sites per year that could pose an imminent health hazard. Prosecutions are expected to result from the priority effort at investigating illegal hazardous waste disposal. (RE)

  17. Petroleum Processing Wastes.

    ERIC Educational Resources Information Center

    Baker, D. A.

    1978-01-01

    Presents a literature review of the petroleum processing wastes, covering publications of 1977. This review covers studies such as the use of activated carbon in petroleum and petrochemical waste treatment. A list of 15 references is also presented. (HM)

  18. HAZARDOUS WASTE DESTRUCTION

    EPA Science Inventory

    The paper profiles the current status of hazardous waste thermal destruction in the United States, including facilities and wastes typically handled. The results of extensive EPA-sponsored performance tests are presented for incinerators, industrial boilers, and industrial proces...

  19. Waste canister for storage of nuclear wastes

    DOEpatents

    Duffy, James B.

    1977-01-01

    A waste canister for storage of nuclear wastes in the form of a solidified glass includes fins supported from the center with the tips of the fins spaced away from the wall to conduct heat away from the center without producing unacceptable hot spots in the canister wall.

  20. Medical waste management plan.

    SciTech Connect

    Lane, Todd W.; VanderNoot, Victoria A.

    2004-12-01

    This plan describes the process for managing research generated medical waste at Sandia National Laboratories/California. It applies to operations at the Chemical and Radiation Detection Laboratory (CRDL), Building 968, and other biosafety level 1 or 2 activities at the site. It addresses the accumulation, storage, treatment and disposal of medical waste and sharps waste. It also describes the procedures to comply with regulatory requirements and SNL policies applicable to medical waste.

  1. Solid waste handling

    SciTech Connect

    Parazin, R.J.

    1995-05-31

    This study presents estimates of the solid radioactive waste quantities that will be generated in the Separations, Low-Level Waste Vitrification and High-Level Waste Vitrification facilities, collectively called the Tank Waste Remediation System Treatment Complex, over the life of these facilities. This study then considers previous estimates from other 200 Area generators and compares alternative methods of handling (segregation, packaging, assaying, shipping, etc.).

  2. Biohazardous waste management plan.

    SciTech Connect

    Lane, Todd W.

    2004-01-01

    This plan describes the process for managing non-medical biohazardous waste at Sandia National Laboratories California. It applies to operations at the Chemical and Radiation Detection Laboratory (CRDL), Building 968, and other biosafety level 1 or 2 activities at the site. It addresses the accumulation, storage, treatment and disposal of biohazardous waste and sharps waste. It also describes the procedures to comply with regulatory requirements and SNL policies applicable to non-medical biohazardous waste.

  3. Solid waste combustion for alpha waste incineration

    SciTech Connect

    Orloff, D.I.

    1981-02-01

    Radioactive waste incinerator development at the Savannah River Laboratory has been augmented by fundamental combustion studies at the University of South Carolina. The objective was to measure and model pyrolysis and combustion rates of typical Savannah River Plant waste materials as a function of incinerator operating conditions. The analytical models developed in this work have been incorporated into a waste burning transient code. The code predicts maximum air requirement and heat energy release as a function of waste type, package size, combustion chamber size, and temperature. Historically, relationships have been determined by direct experiments that did not allow an engineering basis for predicting combustion rates in untested incinerators. The computed combustion rates and burning times agree with measured values in the Savannah River Laboratory pilot (1 lb/hr) and full-scale (12 lb/hr) alpha incinerators for a wide variety of typical waste materials.

  4. GIVE THE PUBLIC SOMETHING, SOMETHING MORE INTERESTING THAN RADIOACTIVE WASTE

    SciTech Connect

    Codee, Hans D.K.

    2003-02-27

    In the Netherlands the policy to manage radioactive waste is somewhat different from that in other countries, although the practical outcome is not much different. Long-term, i.e. at least 100 years, storage in above ground engineered structures of all waste types is the first element in the Dutch policy. Second element, but equally important, is that deep geologic disposal is foreseen after the storage period. This policy was brought out in the early eighties and was communicated to the public as a practical, logical and feasible management system for the Dutch situation. Strong opposition existed at that time to deep disposal in salt domes in the Netherlands. Above ground storage at principle was not rejected because the need to do something was obvious. Volunteers for a long term storage site did not automatically emerge. A site selection procedure was followed and resulted in the present site at Vlissingen-Oost. The waste management organization, COVRA, was not really welcomed here , but was tolerated. In the nineties facilities for low and medium level waste were erected and commissioned. In the design of the facilities much attention was given to emotional factors. The first ten operational years were needed to gain trust from the local population. Impeccable conduct and behavior was necessary as well as honesty and full openness to the public Now, after some ten years, the COVRA facilities are accepted. And a new phase is entered with the commissioning of the storage facility for high level waste, the HABOG facility. A visit to that facility will not be very spectacular, activities take place only during loading and unloading. Furthermore it is a facility for waste, so unwanted material will be brought into the community. In order to give the public something more interesting the building itself is transformed into a piece of art and in the inside a special work of art will be displayed. Together with that the attitude of the company will change. We are

  5. Waste acceptance criteria for closure generated waste

    SciTech Connect

    Not Available

    1992-05-01

    The PORTS Facility has been operating since 1954. The PORTS Facility is used to enrich uranium for nuclear navy applications and commercial nuclear reactors. The PORTS process uses molecular diffusion techniques to separate the U-235 isotope from the U-238 isotope. The PORTS Facility consists of a complex cascade of compressors and converters through which gaseous uranium hexafluoride feed is processed. The feed contains approximately 0.7 percent U-235 by weight while products contain from 4 to 97 percent U-235 by weight, depending on the final application. In general, the majority of the closure wastes generated at PORTS consists of personal protective equipment (PPE), rags, soils, decontamination solutions, and construction related debris. These hazardous wastes will be predominately characterized on the basis of process knowledge. PORTS assumes its conservative waste characterizations that are based on process knowledge are correct unless and until further investigation and/or analysis proves the constituents are not present or are present at concentrations below characteristic regulatory thresholds. Waste Acceptance Criteria for wastes generated by the closure of active and inactive RCRA facilities at PORTS has been developed. The criteria presented in this document govern the activities that are performed during the closure and subsequent generation of waste and relocation from the closure locations to the storage unit. These criteria are intended to ensure the proper handling, classification, processing, and storage of wastes in order to prevent hazardous waste release that may pose a threat to human health or the environment. Any wastes currently stored at each of the facilities that are to be closed will be transferred to the X-326 or X-7725 Storage Units. The waste transfers will be accomplished in accordance with the Container Transfer Plan.

  6. Hazardous Wastes from Homes.

    ERIC Educational Resources Information Center

    Lord, John

    The management of waste materials has become more complex with the increase in human population and the development of new substances. This illustrated booklet traces the history of waste management and provides guidelines for individuals and communities in disposing of certain hazardous wastes safely. It addresses such topics as: (1) how people…

  7. WASTE CONTAINMENT OVERVIEW

    EPA Science Inventory

    BSE waste is derived from diseased animals such as BSE (bovine spongiform encepilopothy, also known as Mad Cow) in cattle and CWD (chronic wasting disease) in deer and elk. Landfilling is examined as a disposal option and this presentation introduces waste containment technology...

  8. Nuclear waste packaging facility

    SciTech Connect

    Mallory, C.W.; Watts, R.E.; Paladino, J.B.; Razor, J.E.; Lilley, A.W.; Winston, S.J.; Stricklin, B.C.

    1987-07-21

    A nuclear waste packaging facility comprising: (a) a first section substantially surrounded by radiation shielding, including means for remotely handling waste delivered to the first section and for placing the waste into a disposal module; (b) a second section substantially surrounded by radiation shielding, including means for handling a deformable container bearing waste delivered to the second section, the handling means including a compactor and means for placing the waste bearing deformable container into the compactor, the compactor capable of applying a compacting force to the waste bearing containers sufficient to inelastically deform the waste and container, and means for delivering the deformed waste bearing containers to a disposal module; (c) a module transportation and loading section disposed between the first and second sections including a means for handling empty modules delivered to the facility and for loading the empty modules on the transport means; the transport means moving empty disposal modules to the first section and empty disposal modules to the second section for locating empty modules in a position for loading with nuclear waste, and (d) a grouting station comprising means for pouring grout into the waste bearing disposal module, and a capping station comprising means for placing a lid onto the waste bearing grout-filled disposal module to completely encapsulate the waste.

  9. Radioactive Wastes. Revised.

    ERIC Educational Resources Information Center

    Fox, Charles H.

    This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. This booklet deals with the handling, processing and disposal of radioactive wastes. Among the topics discussed are: The Nature of Radioactive Wastes; Waste Management; and Research and Development. There are…

  10. Mine waste management

    SciTech Connect

    Hutchinson, I.P.G.; Ellison, R.D.

    1992-01-01

    This book reports on mine waste management. Topics covered include: Performance review of modern mine waste management units; Mine waste management requirements; Prediction of acid generation potential; Attenuation of chemical constituents; Climatic considerations; Liner system design; Closure requirements; Heap leaching; Ground water monitoring; and Economic impact evaluation.

  11. Waste disposal package

    DOEpatents

    Smith, M.J.

    1985-06-19

    This is a claim for a waste disposal package including an inner or primary canister for containing hazardous and/or radioactive wastes. The primary canister is encapsulated by an outer or secondary barrier formed of a porous ceramic material to control ingress of water to the canister and the release rate of wastes upon breach on the canister. 4 figs.

  12. International waste management conference

    SciTech Connect

    Not Available

    1989-01-01

    This book contains the proceedings of the international waste management conference. Topics covered include: Quality assurance in the OCR WM program; Leading the spirit of quality; Dept. of Energy hazardous waste remedial actions program; management of hazardous waste projects; and System management and quality assurance.

  13. Radioactive waste management

    SciTech Connect

    Flax, S.J.

    1981-01-01

    This article examines the technical and legal considerations of nuclear waste management. The first three sections describe the technical aspects of spent-fuel-rod production, reprocessing, and temporary storage. The next two sections discuss permanent disposal of high-level wastes and spent-fuel rods. Finally, legislative and judicial responses to the nuclear-waste crisis.

  14. Look into Waste.

    ERIC Educational Resources Information Center

    Undy, Harry, Ed.

    This booklet is designed to help British teachers introduce concepts of waste to secondary school students. The document focuses on various types of waste and pollution--air, land, water, and industrial--and suggests activities to help students understand and combat waste of natural and human resources. It is presented in 11 chapters. Six chapters…

  15. Municipal waste processing apparatus

    DOEpatents

    Mayberry, J.L.

    1988-04-13

    This invention relates to apparatus for processing municipal waste, and more particularly to vibrating mesh screen conveyor systems for removing grit, glass, and other noncombustible materials from dry municipal waste. Municipal waste must be properly processed and disposed of so that it does not create health risks to the community. Generally, municipal waste, which may be collected in garbage trucks, dumpsters, or the like, is deposited in processing areas such as landfills. Land and environmental controls imposed on landfill operators by governmental bodies have increased in recent years, however, making landfill disposal of solid waste materials more expensive. 6 figs.

  16. Radioactive Waste Management Basis

    SciTech Connect

    Perkins, B K

    2009-06-03

    The purpose of this Radioactive Waste Management Basis is to describe the systematic approach for planning, executing, and evaluating the management of radioactive waste at LLNL. The implementation of this document will ensure that waste management activities at LLNL are conducted in compliance with the requirements of DOE Order 435.1, Radioactive Waste Management, and the Implementation Guide for DOE Manual 435.1-1, Radioactive Waste Management Manual. Technical justification is provided where methods for meeting the requirements of DOE Order 435.1 deviate from the DOE Manual 435.1-1 and Implementation Guide.

  17. The Late Miocene to recent erosion pattern of the Alpine foreland basin reflects Eurasian slab-unloading beneath the western Alps rather than global climate change

    NASA Astrophysics Data System (ADS)

    Friedrich, Anke; Schlunegger, Fritz; Baran, Ramona

    2014-05-01

    yield a large ellipsoidal, orogen-crossing pattern of erosion, centered along the western Alps. Most likely, accelerated erosion of the western Alps and their foreland basin occurred in response to regional-scale surface uplift, related to lithospheric unloading of the European slab along the Eurasian-Adriatic plate boundary. This mechanism triggered large drainage-pattern changes that lead to the establishment of the headwaters for the Rhine and Danube rivers, the largest streams in central Europe. Our findings contradict recent views that substantial erosion of the European Alps since 5 Ma was mainly due to global climate change. Instead, regional-scale tectonic processes have driven this asymmetric erosion pattern during this time.

  18. Mixed waste management options

    SciTech Connect

    Owens, C.B.; Kirner, N.P.

    1991-12-31

    Disposal fees for mixed waste at proposed commercial disposal sites have been estimated to be $15,000 to $40,000 per cubit foot. If such high disposal fees are imposed, generators may be willing to apply extraordinary treatment or regulatory approaches to properly dispose of their mixed waste. This paper explores the feasibility of several waste management scenarios and attempts to answer the question: Can mixed waste be managed out of existence? Existing data on commercially generated mixed waste streams are used to identify the realm of mixed waste known to be generated. Each waste stream is evaluated from both a regulatory and technical perspective in order to convert the waste into a strictly low-level radioactive or a hazardous waste. Alternative regulatory approaches evaluated in this paper include a delisting petition, no migration petition, and a treatability variance. For each waste stream, potentially available treatment options are identified that could lead to these variances. Waste minimization methodology and storage for decay are also considered. Economic feasibility of each option is discussed broadly.

  19. SOLID WASTE STUDY

    SciTech Connect

    PAUL G. ORTIZ - COLEMAN RESEARCH CORP /COMPA INDUSTRIES

    1995-08-01

    The purpose of this document is to study the solid waste issues brought about by a Type C Investigation; ``Disposal of Inappropriate Material in the Los Alamos County Landfill'' (May 28, 1993). The study was completed in August 1995 by Coleman Research Corporation, under subcontract number 405810005-Y for Los Alamos National Laboratory (LANL). The study confirmed the issues identified in the Type C investigation, and also ascertained further issues or problems. During the course of this study two incidents involving hazardous waste resulted in the inappropriate disposal of the waste. An accidental spill, on June 8, 1995, at one of Laboratory buildings was not handled correctly, and ended up in the LAC Landfill. Hazardous waste was disposed of in a solid waste container and sent to the Los Alamos County Landfill. An attempt to locate the hazardous waste at the LAC Landfill was not successful. The second incident involving hazardous waste was discovered by the FSS-8, during a random dumpster surveillance. An interim dumpster program managed by FSS-8 discovered hazardous waste and copper chips in the solid waste, on August 9, 1995. The hazardous waste and copper chips would have been transported to the LAC Landfill if the audit team had not brought the problem to the awareness of the facility waste management personnel.

  20. Mixed waste: Proceedings

    SciTech Connect

    Moghissi, A.A.; Blauvelt, R.K.; Benda, G.A.; Rothermich, N.E.

    1993-12-31

    This volume contains the peer-reviewed and edited versions of papers submitted for presentation a the Second International Mixed Waste Symposium. Following the tradition of the First International Mixed Waste Symposium, these proceedings were prepared in advance of the meeting for distribution to participants. The symposium was organized by the Mixed Waste Committee of the American Society of Mechanical Engineers. The topics discussed at the symposium include: stabilization technologies, alternative treatment technologies, regulatory issues, vitrification technologies, characterization of wastes, thermal technologies, laboratory and analytical issues, waste storage and disposal, organic treatment technologies, waste minimization, packaging and transportation, treatment of mercury contaminated wastes and bioprocessing, and environmental restoration. Individual abstracts are catalogued separately for the data base.

  1. [Recommendations for waste management].

    PubMed

    Vinner, E; Odou, M F; Fovet, B; Ghnassia, J C

    2013-06-01

    Laboratory waste management must ensure the safety of patients and staff, limiting the environmental impacts and control waste disposal budget. Sorting of waste must be carried out at the source. The packaging must be adapted, allowing easy identification of specific disposal routes. With regard to wastes for human or animal health care and/or related research (DASRI), packages must comply with the regulations, standards and ADR if necessary. Storage provisions differ according to the amount of DASRI produced. Waste collection is carried out directly on the place of activity by a certified service provider. Non pre-treated DASRI is incinerated in specific approved plants for a T ° > 1,200 °C. Special provisions also exist for chemical waste and radioactive waste, the latter being regulated by ANDRA. PMID:23765028

  2. New Waste Calcining Facility (NWCF) Waste Streams

    SciTech Connect

    K. E. Archibald

    1999-08-01

    This report addresses the issues of conducting debris treatment in the New Waste Calcine Facility (NWCF) decontamination area and the methods currently being used to decontaminate material at the NWCF.

  3. Stabilization of compactible waste

    SciTech Connect

    Franz, E.M.; Heiser, J.H. III; Colombo, P.

    1990-09-01

    This report summarizes the results of series of experiments performed to determine the feasibility of stabilizing compacted or compactible waste with polymers. The need for this work arose from problems encountered at disposal sites attributed to the instability of this waste in disposal. These studies are part of an experimental program conducted at Brookhaven National Laboratory (BNL) investigating methods for the improved solidification/stabilization of DOE low-level wastes. The approach taken in this study was to perform a series of survey type experiments using various polymerization systems to find the most economical and practical method for further in-depth studies. Compactible dry bulk waste was stabilized with two different monomer systems: styrene-trimethylolpropane trimethacrylate (TMPTMA) and polyester-styrene, in laboratory-scale experiments. Stabilization was accomplished by wetting or soaking compactible waste (before or after compaction) with monomers, which were subsequently polymerized. Three stabilization methods are described. One involves the in-situ treatment of compacted waste with monomers in which a vacuum technique is used to introduce the binder into the waste. The second method involves the alternate placement and compaction of waste and binder into a disposal container. In the third method, the waste is treated before compaction by wetting the waste with the binder using a spraying technique. A series of samples stabilized at various binder-to-waste ratios were evaluated through water immersion and compression testing. Full-scale studies were conducted by stabilizing two 55-gallon drums of real compacted waste. The results of this preliminary study indicate that the integrity of compacted waste forms can be readily improved to ensure their long-term durability in disposal environments. 9 refs., 10 figs., 2 tabs.

  4. Waste Inspection Tomography (WIT)

    SciTech Connect

    Bernardi, R.T.

    1995-12-01

    Waste Inspection Tomography (WIT) provides mobile semi-trailer mounted nondestructive examination (NDE) and assay (NDA) for nuclear waste drum characterization. WIT uses various computed tomography (CT) methods for both NDE and NDA of nuclear waste drums. Low level waste (LLW), transuranic (TRU), and mixed radioactive waste can be inspected and characterized without opening the drums. With externally transmitted x-ray NDE techniques, WIT has the ability to identify high density waste materials like heavy metals, define drum contents in two- and three-dimensional space, quantify free liquid volumes through density and x-ray attenuation coefficient discrimination, and measure drum wall thickness. With waste emitting gamma-ray NDA techniques, WIT can locate gamma emitting radioactive sources in two- and three-dimensional space, identify gamma emitting isotopic species, identify the external activity levels of emitting gamma-ray sources, correct for waste matrix attenuation, provide internal activity approximations, and provide the data needed for waste classification as LLW or TRU. The mobile feature of WIT allows inspection technologies to be brought to the nuclear waste drum storage site without the need to relocate drums for safe, rapid, and cost-effective characterization of regulated nuclear waste. The combination of these WIT characterization modalities provides the inspector with an unprecedented ability to non-invasively characterize the regulated contents of waste drums as large as 110 gallons, weighing up to 1,600 pounds. Any objects that fit within these size and weight restrictions can also be inspected on WIT, such as smaller waste bags and drums that are five and thirty-five gallons.

  5. Solid Waste Management Plan. Revision 4

    SciTech Connect

    1995-04-26

    The waste types discussed in this Solid Waste Management Plan are Municipal Solid Waste, Hazardous Waste, Low-Level Mixed Waste, Low-Level Radioactive Waste, and Transuranic Waste. The plan describes for each type of solid waste, the existing waste management facilities, the issues, and the assumptions used to develop the current management plan.

  6. High level nuclear waste

    SciTech Connect

    Crandall, J L

    1980-01-01

    The DOE Division of Waste Products through a lead office at Savannah River is developing a program to immobilize all US high-level nuclear waste for terminal disposal. DOE high-level wastes include those at the Hanford Plant, the Idaho Chemical Processing Plant, and the Savannah River Plant. Commercial high-level wastes, for which DOE is also developing immobilization technology, include those at the Nuclear Fuel Services Plant and any future commercial fuels reprocessing plants. The first immobilization plant is to be the Defense Waste Processing Facility at Savannah River, scheduled for 1983 project submission to Congress and 1989 operation. Waste forms are still being selected for this plant. Borosilicate glass is currently the reference form, but alternate candidates include concretes, calcines, other glasses, ceramics, and matrix forms.

  7. Processing of nuclear waste

    SciTech Connect

    Hennelly, E.J.

    1981-01-01

    The processing of nuclear waste to transform the liquid waste from fuel reprocessing activities is well defined. Most solid waste forms, if they are cooled and contain diluted waste, are compatible with many permanent storage environments. The public acceptance of methods for disposal is being delayed in the US because of the alternatives studies of waste forms and repositories now under way that give the impression of indecision and difficulty for the disposal of HLW. Conservative programs that dilute and cool solid waste are under way in France and Sweden and demonstrate that a solution to the problem is available now. Research and development should be directed toward improving selected methods rather than seeking a best method, which at best, may always be illusory.

  8. Storing Waste in Ceramic

    SciTech Connect

    Bourcier, W L; Sickafus, K

    2004-07-20

    Not all the nuclear waste destined for Yucca Mountain is in the form of spent fuel. Some of it will be radioactive waste generated from the production of nuclear weapons. This so-called defense waste exists mainly as corrosive liquids and sludge in underground tanks. An essential task of the U.S. high-level radioactive waste program is to process these defense wastes into a solid material--called a waste form. An ideal waste form would be extremely durable and unreactive with other repository materials. It would be simple to fabricate remotely so that it could be safely transported to a repository for permanent storage. What's more, the material should be able to tolerate exposure to intense radiation without degradation. And to minimize waste volume, the material must be able to contain high concentrations of radionuclides. The material most likely to be used for immobilization of radioactive waste is glass. Glasses are produced by rapid cooling of high-temperature liquids such that the liquid-like non-periodic structure is preserved at lower temperatures. This rapid cooling does not allow enough time for thermodynamically stable crystalline phases (mineral species) to form. In spite of their thermodynamic instability, glasses can persist for millions of years. An alternate to glass is a ceramic waste form--an assemblage of mineral-like crystalline solids that incorporate radionuclides into their structures. The crystalline phases are thermodynamically stable at the temperature of their synthesis; ceramics therefore tend to be more durable than glasses. Ceramic waste forms are fabricated at temperatures below their melting points and so avoid the danger of handling molten radioactive liquid--a danger that exists with incorporation of waste in glasses. The waste form provides a repository's first line of defense against release of radionuclides. It, along with the canister, is the barrier in the repository over which we have the most control. When a waste form is

  9. Underground waste barrier structure

    DOEpatents

    Saha, Anuj J.; Grant, David C.

    1988-01-01

    Disclosed is an underground waste barrier structure that consists of waste material, a first container formed of activated carbonaceous material enclosing the waste material, a second container formed of zeolite enclosing the first container, and clay covering the second container. The underground waste barrier structure is constructed by forming a recessed area within the earth, lining the recessed area with a layer of clay, lining the clay with a layer of zeolite, lining the zeolite with a layer of activated carbonaceous material, placing the waste material within the lined recessed area, forming a ceiling over the waste material of a layer of activated carbonaceous material, a layer of zeolite, and a layer of clay, the layers in the ceiling cojoining with the respective layers forming the walls of the structure, and finally, covering the ceiling with earth.

  10. Waste from grocery stores

    SciTech Connect

    Lieb, K.

    1993-11-01

    The Community Recycling Center, Inc., (CRC, Champaign, Ill.), last year conducted a two-week audit of waste generated at two area grocery stores. The stores surveyed are part of a 10-store chain. For two of the Kirby Foods Stores, old corrugated containers (OCC) accounted for 39-45% of all waste. The summary drew correlations between the amount of OCC and the sum of food and garbage waste. The study suggested that one can reasonably estimate volumes of waste based on the amount of OCC because most things come in a box. Auditors set up a series of containers to make the collection process straightforward. Every day the containers were taken to local recycling centers and weighed. Approximate waste breakdowns for the two stores were as follows: 45% OCC; 35% food waste; 20% nonrecyclable or noncompostable items; and 10% other.

  11. Operational waste volume projection

    SciTech Connect

    Koreski, G.M.; Strode, J.N.

    1995-06-01

    Waste receipts to the double-shell tank system are analyzed and wastes through the year 2015 are projected based on generation trends of the past 12 months. A computer simulation of site operations is performed, which results in projections of tank fill schedules, tank transfers, evaporator operations, tank retrieval, and aging waste tank usage. This projection incorporates current budget planning and the clean-up schedule of the tri-party agreement. Assumptions are current as of June 1995.

  12. Operational Waste Volume Projection

    SciTech Connect

    STRODE, J.N.

    1999-08-24

    Waste receipts to the double-shell tank system are analyzed and wastes through the year 2018 are projected based on assumption as of July 1999. A computer simulation of site operations is performed, which results in projections of tank fill schedules, tank transfers, evaporator operations, tank retrieval, and aging waste tank usage. This projection incorporates current budget planning and the clean-up schedule of the Tri-Party Agreement.

  13. Characteristics of healthcare wastes.

    PubMed

    Diaz, L F; Eggerth, L L; Enkhtsetseg, Sh; Savage, G M

    2008-01-01

    A comprehensive understanding of the quantities and characteristics of the material that needs to be managed is one of the most basic steps in the development of a plan for solid waste management. In this case, the material under consideration is the solid waste generated in healthcare facilities, also known as healthcare waste. Unfortunately, limited reliable information is available in the open literature on the quantities and characteristics of the various types of wastes that are generated in healthcare facilities. Thus, sound management of these wastes, particularly in developing countries, often is problematic. This article provides information on the quantities and properties of healthcare wastes in various types of facilities located in developing countries, as well as in some industrialized countries. Most of the information has been obtained from the open literature, although some information has been collected by the authors and from reports available to the authors. Only data collected within approximately the last 15 years and using prescribed methodologies are presented. The range of hospital waste generation (both infectious and mixed solid waste fractions) varies from 0.016 to 3.23kg/bed-day. The relatively wide variation is due to the fact that some of the facilities surveyed in Ulaanbaatar include out-patient services and district health clinics; these facilities essentially provide very basic services and thus the quantities of waste generated are relatively small. On the other hand, the reported amount of infectious (clinical, yellow bag) waste varied from 0.01 to 0.65kg/bed-day. The characteristics of the components of healthcare wastes, such as the bulk density and the calorific value, have substantial variability. This literature review and the associated attempt at a comparative analysis point to the need for worldwide consensus on the terms and characteristics that describe wastes from healthcare facilities. Such a consensus would greatly

  14. Waste not, want not

    NASA Astrophysics Data System (ADS)

    Thompson, Frank

    2015-03-01

    Sadly, modern society has developed very wasteful habits over the last few decades: consumer products, food and energy are perphaps waste items that are most obvious. Attempting to show how we can counteract wasteful habits, this article (a) makes reference to Helen Czerski in her efforts to stop her cycle from rusting away; and (b) shows how a relatively simple task can give new life to a domestic toaster.

  15. Guidelines for mixed waste minimization

    SciTech Connect

    Owens, C.

    1992-02-01

    Currently, there is no commercial mixed waste disposal available in the United States. Storage and treatment for commercial mixed waste is limited. Host States and compacts region officials are encouraging their mixed waste generators to minimize their mixed wastes because of management limitations. This document provides a guide to mixed waste minimization.

  16. Hazardous waste tracking issues

    SciTech Connect

    Marvin, R. )

    1993-08-01

    The concept of cradle-to-grave oversight of hazardous waste was established in 1976 under RCRA. Since then, the multicopy Uniform Hazardous Waste Manifest has been a key component in the federal tracking system. The manifests ensure that generators, transporters and TSDFs maintain documentation of hazardous waste shipments. To a large extent, the tracking system has served its intended purpose; nevertheless, certain shortcomings exist. Anyone involved in shipping hazardous waste should be aware of the system's weaknesses and take appropriate measures to compensate for them.

  17. Avoidable waste management costs

    SciTech Connect

    Hsu, K.; Burns, M.; Priebe, S.; Robinson, P.

    1995-01-01

    This report describes the activity based costing method used to acquire variable (volume dependent or avoidable) waste management cost data for routine operations at Department of Energy (DOE) facilities. Waste volumes from environmental restoration, facility stabilization activities, and legacy waste were specifically excluded from this effort. A core team consisting of Idaho National Engineering Laboratory, Los Alamos National Laboratory, Rocky Flats Environmental Technology Site, and Oak Ridge Reservation developed and piloted the methodology, which can be used to determine avoidable waste management costs. The method developed to gather information was based on activity based costing, which is a common industrial engineering technique. Sites submitted separate flow diagrams that showed the progression of work from activity to activity for each waste type or treatability group. Each activity on a flow diagram was described in a narrative, which detailed the scope of the activity. Labor and material costs based on a unit quantity of waste being processed were then summed to generate a total cost for that flow diagram. Cross-complex values were calculated by determining a weighted average for each waste type or treatability group based on the volume generated. This study will provide DOE and contractors with a better understanding of waste management processes and their associated costs. Other potential benefits include providing cost data for sites to perform consistent cost/benefit analysis of waste minimization and pollution prevention (WMIN/PP) options identified during pollution prevention opportunity assessments and providing a means for prioritizing and allocating limited resources for WMIN/PP.

  18. WASTE PACKAGE TRANSPORTER DESIGN

    SciTech Connect

    D.C. Weddle; R. Novotny; J. Cron

    1998-09-23

    The purpose of this Design Analysis is to develop preliminary design of the waste package transporter used for waste package (WP) transport and related functions in the subsurface repository. This analysis refines the conceptual design that was started in Phase I of the Viability Assessment. This analysis supports the development of a reliable emplacement concept and a retrieval concept for license application design. The scope of this analysis includes the following activities: (1) Assess features of the transporter design and evaluate alternative design solutions for mechanical components. (2) Develop mechanical equipment details for the transporter. (3) Prepare a preliminary structural evaluation for the transporter. (4) Identify and recommend the equipment design for waste package transport and related functions. (5) Investigate transport equipment interface tolerances. This analysis supports the development of the waste package transporter for the transport, emplacement, and retrieval of packaged radioactive waste forms in the subsurface repository. Once the waste containers are closed and accepted, the packaged radioactive waste forms are termed waste packages (WP). This terminology was finalized as this analysis neared completion; therefore, the term disposal container is used in several references (i.e., the System Description Document (SDD)) (Ref. 5.6). In this analysis and the applicable reference documents, the term ''disposal container'' is synonymous with ''waste package''.

  19. Nuclear Waste Disposal

    SciTech Connect

    Gee, Glendon W.; Meyer, Philip D.; Ward, Andy L.

    2005-01-12

    Nuclear wastes are by-products of nuclear weapons production and nuclear power generation, plus residuals of radioactive materials used by industry, medicine, agriculture, and academia. Their distinctive nature and potential hazard make nuclear wastes not only the most dangerous waste ever created by mankind, but also one of the most controversial and regulated with respect to disposal. Nuclear waste issues, related to uncertainties in geologic disposal and long-term protection, combined with potential misuse by terrorist groups, have created uneasiness and fear in the general public and remain stumbling blocks for further development of a nuclear industry in a world that may soon be facing a global energy crisis.

  20. Mixed waste characterization strategy

    SciTech Connect

    Baldwin, C.E.; Stakebake, J.; Peters, M.

    1992-01-01

    Radioactive mixed wastes containing a radioactive component subject to the Atomic Energy Act (AEA) and hazardous waste subject to resource Conservation and Recovery Act (RCRA) are generated, treated, and stored at the Rocky Flats Plant (RFP) and are subject to federal and state statutory and regulatory requirements. The US Environmental Protection Agency (EPA) and the Colorado Department of Health (CDH) are the two primary regulatory agencies which enforce these requirements. This paper describes the mechanism by which RFP will characterize mixed wastes within the LDR provisions of RCRA and the LDR FFCA as well as for meeting the waste acceptance criteria for disposal.