1,867 research outputs found
Valuing Fed Cattle Using Objective Tenderness Measures
Beef tenderness is critical in consumer satisfaction with beef steak products. Current fed cattle valuation systems do not differentiate carcasses based upon tenderness variation. However, considerable research indicates consumers are willing to pay more for tender relative to tough beef steak. This article develops a tenderness-augmentation to current fed cattle grid pricing systems. Using a large set of actual carcasses, we determine that a tenderness-augmented price grid would reorder fed cattle value by on average nearly $5.00/cwt dressed relative to current valuation methods. Substantial opportunity is present to improve beef tenderness through new price signals to producers.beef quality, meat tenderness, cattle value, cattle price, Agribusiness, Farm Management, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries, Q11, Q13, M31,
Genetic Regulation of Bone and Cells by Electromagnetic Stimulation Fields and Uses Thereof
The present invention provides methods to modify the genetic regulation of mammalian tissue, bone, cells or any combination thereof by preferential activation, up-regulation and/or down-regulation. The method comprises steps of tuning the predetermined profiles of one or more time-varying stimulation fields by manipulating the B-Field magnitude, rising slew rate, rise time, falling slew rate, fall time, frequency, wavelength, and duty cycle, and exposing mammalian cells or tissues to one or more tuned time-varying stimulation fields with predetermined profiles. Examples of mammalian cells or tissues are chondrocytes, osteoblasts, osteocytes, osteoclasts, nucleus pulposus, associated tissue, or any combination. The resulted modification on gene regulation of these cells, tissues or bones may promote the retention, repair of and reduction of compromised mammalian cartilage, bone, and associated tissue
Dietary Acid Load and Bone Turnover During Long-Duration Spaceflight and Bed Rest
Background Bed rest studies document that a lower dietary acid load is associated with lower bone resorption. Objective We tested the effect of dietary acid load on bone metabolism during spaceflight. Design Controlled 4-d diets with a high or low animal proteinto-potassium (APro:K) ratio (High and Low diets, respectively) were given to 17 astronauts before and during spaceflight. Each astronaut had 1 High and 1 Low diet session before flight and 2 High and 2 Low sessions during flight, in addition to a 4-d session around flight day 30 (FD30), when crew members were to consume their typical in-flight intake. At the end of each session, blood and urine samples were collected. Calcium, total protein, energy, and sodium were maintained in each crew member's preflight and in-flight controlled diets. Results Relative to preflight values, N-telopeptide (NTX) and urinary calcium were higher during flight, and bone-specific alkaline phosphatase (BSAP) was higher toward the end of flight. The High and Low diets did not affect NTX, BSAP, or urinary calcium. Dietary sulfur and age were significantly associated with changes in NTX. Dietary sodium and flight day were significantly associated with urinary calcium during flight. The net endogenous acid production (NEAP) estimated from the typical dietary intake at FD30 was associated with loss of bone mineral content in the lumbar spine after the mission. The results were compared with data from a 70-d bed rest study, in which control (but not exercising) subjects APro:K was associated with higher NTX during bed rest. Conclusions Long-term lowering of NEAP by increasing vegetable and fruit intake may protect against changes in loss of bone mineral content during spaceflight when adequate calcium is consumed, particularly if resistive exercise is not being performed. This trial was registered at clinicaltrials.gov as NCT01713634
Alendronate and Resistive Exercise Countermeasures Against Bed Rest-Induced Bone Loss: Biochemical Markers of Bone and Calcium Metabolism
Weightlessness-induced bone loss must be counteracted to ensure crew health during extendedduration space missions. Studies were conducted to assess two bone loss countermeasures in a ground-based model: horizontal bed rest. Following a 3-wk ambulatory adaptation period, male and female subjects (aged 21-56 y) completed a 17-wk bed rest protocol. Subjects were assigned to one of three treatments: alendronate (ALEN; 10 mg/d, n=6), resistive exercise (RE; 1.5 h/d, 6 d/wk, n=8), or control (CN; no countermeasure, n=8). Dietary intake was adjusted to maintain body weight. Endocrine and biochemical indices were measured in blood and urine using standard laboratory methods. All data reported are expressed as percent change from individual pre-bedrest data. Serum calcium changed little during bed rest, and tended to decrease (4-8%) in ALEN subjects. In RE subjects, bone alkaline phosphatase and osteocalcin were increased >65 and >30%, respectively, during bed rest, while these were unchanged or decreased in ALEN and CN subjects. Urinary calcium was increased 50% in CN subjects, but was unchanged or decreased in both ALEN and RE groups. Urinary n-telopeptide excretion was increased 40-50% in CN and RE subjects, but decreased 20% in ALEN subjects. Pyridinium crosslink and deoxypyridinoline excretion were increased 20-50% during bed rest. These data suggest that RE countermeasures are effective at increasing markers of bone formation in an analog of weightlessness, while ALEN reduces markers of bone resorption. Counteracting the bone loss of space flight may require both pharmacologic and exercise countermeasures
What Happens to bone health during and after spaceflight?
Weightless conditions of space flight accelerate bone loss. There are no reports to date that address whether the bone that is lost during spaceflight could ever be recovered. Spaceinduced bone loss in astronauts is evaluated at the Johnson Space Center (JSC) by measurement of bone mineral density (BMD) by Dual-energy x-ray absorptiometry (DXA) scans. Astronauts are routinely scanned preflight and at various time points postflight (greater than or equal to Return+2 days). Two sets of BMD data were used to model spaceflight-induced loss and skeletal recovery in crewmembers following long-duration spaceflight missions (4-6 months). Group I was from astronauts (n=7) who were systematically scanned at multiple time points during the postflight period as part of a research protocol to investigate skeletal recovery. Group II came from a total of 49 sets of preflight and postflight data obtained by different protocols. These data were from 39 different crewmembers some of whom served on multiple flights. Changes in BMD (between pre- and postflight BMD) were plotted as a function of time (days-after-landing); plotted data were fitted to an exponential equation which enabled estimations of i) BMD change at day 0 after landing and ii) the number of days by which 50% of the lost bone is recovered (half-life). These fits were performed for BMD of the lumbar spine, trochanter, pelvis, femoral neck and calcaneus. There was consistency between the models for BMD recovery. Based upon the exponential model of BMD restoration, recovery following long-duration missions appears to be substantially complete in crewmembers within 36 months following return to Earth
Translational Research and Medicine at NASA: From Earth to Space and Back Again
The Space Environment provides many challenges to the human physiology and therefore to extended habitation and exploration. Translational research and medical strategies are meeting these challenges by combining Earth based medical solutions with innovative and developmental engineering approaches. Translational methodologies are current applied to spaceflight related dysregulations in the areas of: (1) cardiovascular fluid shifts, intracranial hypertension and neuro-ocular impairment 2) immune insufficiency and suppression/viral re-expression, 3) bone loss and fragility (osteopenia/osteoporosis) and muscle wasting, and finally 4) radiation sensitivity and advanced ageing. Over 40 years of research into these areas have met with limited success due to lack of tools and basic understanding of central issues that cause physiologic maladaptaion and distrupt homeostatis. I will discuss the effects of living in space (reduced gravity, increased radiation and varying atmospheric conditions [EVA]) during long-duration, exploration-class missions and how translational research has benefited not only space exploration but also Earth based medicine. Modern tools such as telemedicine advances in genomics, proteomics, and metabolomics (Omicssciences) has helped address syndromes, at the systemic level by enlisting a global approach to assessing spaceflight physiology and to develop countermeasures thereby permitting our experience in space to be translated to the Earth's medical community
Alendronate as an Effective Countermeasure to Disuse Induced Bone loss
Microgravity, similar to diuse immobilization on earth, causes rapid bone loss. This loss is believed to be an adaptive response to the reduced musculoskelatal forces in space and occurs gradually enough that changes occurring during short duration space flight are not a concern. Bone loss, however, will be a major impediment for long duration missions if effective countermeasures are not developed and implemented. Bed rest is used to simulate the reduced mechanical forces in humans and was used to test the hypothesis that oral alendronate would reduce the effects of long duration (17 weeks) inactivity on bone. Eight male subjects were given daily oral doses of alendronate during 17 weeks of horizontal bed rest and compared with 13 male control subjects not given the drug. Efficacy was evaluated based on measurements of bone markers, calcium balance and bone density performed before, during and after the bed rest. The results show that oral alendronate attenuates most of the characteristic changes associated with long duration bed rest and presumably space flight
3D-electrical resistivity tomography monitoring of salt transport in homogeneous and layered soil samples
Monitoring transport of dissolved substances in soil deposits is particularly relevant where safety is concerned, as in the case of geo-environmental barriers. Geophysical methods are very appealing, since they cover a wide domain, localising possible preferential flow paths and providing reliable links between geophysical quantities and hydrological variables. This paper describes a 3D laboratory application of Electrical Resistivity Tomography (ERT) used to monitor solute transport processes. Dissolution and transport tests on both homogeneous and heterogeneous samples were conducted in an instrumented oedometer cell. ERT was used to create maps of electrical conductivity of the monitored domain at different time intervals and to estimate concentration variations within the interstitial fluid. Comparisons with finite element simulations of the transport processes were performed to check the consistency of the results. Tests confirmed that the technique can monitor salt transport, infer the hydro-chemical behaviour of heterogeneous geomaterials and evaluate the performances of clay barrier
Skeletal Recovery Following Long-Duration Spaceflight Missions as Determined by Preflight and Postflight DXA Scans of 45 Crew Members
Introduction: The loss of bone mineral in astronauts during spaceflight has been investigated throughout the more than 40 years of bone research in space. Consequently, it is a medical requirement at NASA that changes in bone mass be monitored in crew members by measurements of bone mineral density (BMD) with dual-energy x-ray absorptiometry (DXA). This report is the first to evaluate medical data to address the recovery of bone mineral that is lost during spaceflight. Methods: DXA scans are performed before and after flight in astronauts who serve on long-duration missions (4-6 months) to ensure that medical standards for flight certification are met, to evaluate the effects of spaceflight and to monitor the restoration to preflight BMD status after return to Earth. Through cooperative agreements with the Russian Space Agency, the Bone and Mineral Lab at NASA Johnson Space Center (Houston, TX), also had access to BMD data from cosmonauts who had flown on long-duration missions yielding data from a total of 45 individual crew members. Changes in BMD (between 56 different sets of pre- and postflight measurements) were plotted as a function of time (days after landing); plotted data were fitted to an exponential mathematical model that determined i) BMD change at day 0 after landing and ii) the number of days after which 50% of the lost bone was recovered ("Recovery Half-Life"). These fits were performed for BMD of the lumbar spine, trochanter, pelvis, femoral neck and calcaneus. Results: In sum, averaged losses of bone mineral after spaceflight ranged between 2-9% for sites in the axial and appendicular skeleton. The fitted postflight BMD values predicted a 50% recovery of bone loss for all sites within 9 months
Adaptation of the Skeletal System during Long-duration Spaceflight
This review will highlight evidence from crew members flown on space missions greater than 90 days to suggest that the adaptations of the skeletal system to mechanical unloading may predispose crew members to an accelerated onset of osteoporosis after return to Earth. By definition, osteoporosis is a skeletal disorder - characterized by low bone mineral density and structural deterioration - that reduces the ability of bones to resist fracture under the loading of normal daily activities. Involutional or agerelated osteoporosis is readily recognized as a syndrome afflicting the elderly population because of the insipid and asymptomatic nature of bone loss that does not typically manifest as fractures until after age approximately 60. It is not the thesis of this review to suggest that spaceflight-induced bone loss is similar to bone loss induced by metabolic bone disease; rather this review draws parallels between the rapid and earlier loss in females that occurs with menopause and the rapid bone loss in middle-aged crew members that occurs with spaceflight unloading and how the cumulative effects of spaceflight and ageing could be detrimental, particularly if skeletal effects are totally or partially irreversible. In brief, this report will provide detailed evidence that long-duration crew members, exposed to the weightlessness of space for the typical long-duration (4-6 months) mission on Mir or the International Space Station -- 1. Display bone resorption that is aggressive, that targets normally weight-bearing skeletal sites, that is uncoupled to bone formation and that results in areal BMD deficits that can range between 6-20% of preflight BMD; 2. Display compartment-specific declines in volumetric BMD in the proximal femur (a skeletal site of clinical interest) that significantly reduces its compressive and bending strength and which may account for the loss in hip bone strength (i.e., force to failure); 3. Recover BMD over a post-flight time period that exceeds spaceflight exposure but for which the restoration of whole bone strength remains an open issue and may involve structural alteration; and 4. Display risk factors for bone loss -- such as the negative calcium balance and down-regulated calcium-regulating hormones in response to bone atrophy -- that can be compounded by the constraints of conducting mission operations (inability to provide essential nutrients and vitamins). The full characterization of the skeletal response to mechanical unloading in space is not complete. In particular, countermeasures used to date have been inadequate and it is not yet known whether more appropriate countermeasures can prevent the changes in bone that have been found in previous flights, knowledge gaps related to the effects of prolonged (greater than or equal to 6 months) space exposure and to partial gravity environments are substantial, and longitudinal measurements on crew members after spaceflight are required to assess the full impact on skeletal recovery
- …
