1,467 research outputs found

    Evaluation of positive G sub Z tolerance following simulated weightlessness (bedrest)

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    The magnitude of physiologic changes which are known to occur in human subjects exposed to varying levels of + G sub Z acceleration following bed rest simulation of weightlessness was studied. Bed rest effects were documented by fluid and electrolyte balance studies, maximal exercise capability, 70 deg passive tilt and lower body negative pressure tests and the ability to endure randomly prescribed acceleration profiles of +2G sub Z, +3G sub Z, and +4G sub Z. Six healthy male volunteers were studied during two weeks of bed rest after adequate control observations, followed by two weeks of recovery, followed by a second two-week period of bed rest at which time an Air Force cutaway anti-G suit was used to determine its effectiveness as a countermeasure for observed cardiovascular changes during acceleration. Results showed uniform and significant changes in all measured parameters as a consequence of bed rest including a reduced ability to tolerate +G sub Z acceleration. The use of anti-G suits significantly improved subject tolerance to all G exposures and returned measured parameters such as heart rate and blood pressure towards or to pre-bed-rest (control) values in four of the six cases

    Flat Plate Solar Collector Materials (and Designs with an Economic Methodology for Optimizing Collector Design)

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    The desirability of specific materials and designs for conventional flat-plate solar collector components is considered. Then a methodology for choosing the most economic component is presented, consisting of a computer simulation and a rate-of-return analysis. The effect of rising conventional fuel costs is examined. Examples of using the methodology are given, based on Southern California climatic and user-demand conditions. Selective absorber-plate coatings and film inner glazing are shown to be economic, yielding a rate-of-return of 23 percent and 29 percent, respectively

    Prevention of bone mineral changes induced by bed rest: Modification by static compression simulating weight bearing, combined supplementation of oral calcium and phosphate, calcitonin injections, oscillating compression, the oral diophosphonatedisodium etidronate, and lower body negative pressure

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    The phenomenon of calcium loss during bed rest was found to be analogous to the loss of bone material which occurs in the hypogravic environment of space flight. Ways of preventing this occurrence are investigated. A group of healthy adult males underwent 24-30 weeks of continuous bed rest. Some of them were given an exercise program designed to resemble normal ambulatory activity; another subgroup was fed supplemental potassium phosphate. The results from a 12-week period of treatment were compared with those untreated bed rest periods. The potassium phosphate supplements prevented the hypercalciuria of bed rest, but fecal calcium tended to increase. The exercise program did not diminish the negative calcium balance. Neither treatment affected the heavy loss of mineral from the calcaneus. Several additional studies are developed to examine the problem further

    Evolution of phase assemblage of blended magnesium potassium phosphate cement binders at 200 degrees and 1000 degrees C

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    The fire performance of magnesium potassium phosphate cement (MKPC) binders blended with fly ash (FA) and ground granulated blast furnace slag (GBFS) was investigated up to 1000°C using X-ray diffraction, thermogravimetric analysis and SEM techniques. The FA/MKPC and GBFS/MKPC binders dehydrate above 200°C to form amorphous KMgPO4, concurrent with volumetric and mass changes. Above 1000°C, additional crystalline phases were formed and microstructural changes occurred, although no cracking or spalling of the samples was observed. These results indicate that FA/MKPC and GBFS/MKPC binders are expected to have satisfactory fire performance under the fire scenario conditions relevant to the operation of a UK or other geological disposal facility

    New Measurements of Fine-Scale CMB Polarization Power Spectra from CAPMAP at Both 40 and 90 GHz

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    We present new measurements of the cosmic microwave background (CMB) polarization from the final season of the Cosmic Anisotropy Polarization MAPper (CAPMAP). The data set was obtained in winter 2004-2005 with the 7 m antenna in Crawford Hill, New Jersey, from 12 W-band (84-100 GHz) and 4 Q-band (36-45 GHz) correlation polarimeters with 3.3' and 6.5' beamsizes, respectively. After selection criteria were applied, 956 (939) hours of data survived for analysis of W-band (Q-band) data. Two independent and complementary pipelines produced results in excellent agreement with each other. A broad suite of null tests as well as extensive simulations showed that systematic errors were minimal, and a comparison of the W-band and Q-band sky maps revealed no contamination from galactic foregrounds. We report the E-mode and B-mode power spectra in 7 bands in the range 200 < l < 3000, extending the range of previous measurements to higher l. The E-mode spectrum, which is detected at 11 sigma significance, is in agreement with cosmological predictions and with previous work at other frequencies and angular resolutions. The BB power spectrum provides one of the best limits to date on B-mode power at 4.8 uK^2 (95% confidence).Comment: 19 pages, 17 figures, 2 tables, submitted to Ap

    Repeated administration of phytocannabinoid Δ9-THC or synthetic cannabinoids JWH-018 and JWH-073 induces tolerance to hypothermia but not locomotor suppression in mice, and reduces CB1 receptor expression and function in a brain region-specific manner

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    These studies probed the relationship between intrinsic efficacy and tolerance / cross-tolerance between Δ9-THC and synthetic cannabinoid drugs of abuse (SCBs) by examining in vivo effects and cellular changes concomitant with their repeated administration in mice. Dose-effect relationships for hypothermic effects were determined in order to confirm that SCBs JWH-018 and JWH-073 are higher efficacy agonists than Δ9-THC in mice. Separate groups of mice were treated with saline, sub-maximal hypothermic doses of JWH-018 or JWH-073 (3.0 mg/kg or 10.0 mg/kg, respectively) or a maximally hypothermic dose of 30.0 mg/kg Δ9-THC once per day for 5 consecutive days while core temperature and locomotor activity were monitored via biotelemetry. Repeated administration of all drugs resulted in tolerance to hypothermic effects, but not locomotor effects, and this tolerance was still evident 14 days after the last drug administration. Further studies treated mice with 30.0 mg/kg Δ9-THC once per day for 4 days, then tested with SCBs on day 5. Mice with a Δ9-THC history were cross-tolerant to both SCBs, and this cross-tolerance also persisted 14 days after testing. Select brain regions from chronically treated mice were examined for changes in CB1 receptor expression and function. Expression and function of hypothalamic CB1Rs were reduced in mice receiving chronic drugs, but cortical CB1R expression and function were not altered. Collectively, these data demonstrate that repeated Δ9-THC, JWH-018 and JWH-073 can induce long-lasting tolerance to some in vivo effects, which is likely mediated by region-specific downregulation and desensitization of CB1Rs

    The progression of deoxynivalenol-induced growth suppression in nursery pigs and the potential of an algae-modified montmorillonite clay to mitigate these effects

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    Citation: Frobose, H. L., Erceg, J. A., Fowler, S. Q., Tokach, M. D., DeRouchey, J. M., Woodworth, J. C., . . . Goodband, R. D. (2016). The progression of deoxynivalenol-induced growth suppression in nursery pigs and the potential of an algae-modified montmorillonite clay to mitigate these effects. Journal of Animal Science, 94(9), 3746-3759. doi:10.2527/jas2016-0663Two experiments were conducted to characterize the progression of deoxynivalenol (DON)-induced growth suppression and to investigate algae-modified montmorillonite clay (AMMC) as a means to alleviate the effects of DON in nursery pigs. In both experiments, naturally DON-contaminated wheat was used to produce diets with desired DON levels. In Exp. 1, 280 barrows and gilts (10.0 +/- 0.2 kg BW) were used in a 28-d experiment arranged in a 2 x 2 + 1 factorial design with 8 replicates per treatment. The 5 treatments consisted of 2 positive control (PC) diets with DON below detection limits and with or without 0 or 0.50% AMMC and 3 negative control (NC) diets with 5 mg/kg of DON and containing 0, 0.25, or 0.50% AMMC. No DON x AMMC interactions were observed. Overall, pigs fed DON had decreased (P < 0.001) ADG and final BW regardless of AMMC addition. Feeding DON-contaminated diets elicited the most severe depression (P < 0.001) in ADFI and G:F from d 0 to 3, remaining poorer overall (P < 0.01) but lessening in severity as exposure time increased. Pigs fed DON diets had greater (P < 0.05) within pen BW variation (CV) on d 28. Although the addition of 0.50% AMMC to diets restored (P < 0.05) ADFI from d 14 to 21 to levels similar to the PC, no other differences were observed for AMMC inclusion. In Exp. 2, 360 barrows (11.4 +/- 0.2 kg BW) were used in a 21-d experiment with 9 dietary treatments arranged in a 3 x 3 factorial design with DON and AMMC inclusion as main effects. There were 8 replicate pens per treatment. Treatments consisted of 3 PC diets without DON, 3 low-DON (1.5 mg/kg DON) NC diets, and 3 high-DON (3 mg/kg DON) NC diets with 0, 0.17, or 0.50% AMMC incorporated at each DON level. No DON x AMMC interactions were observed. As DON level increased, ADG and final BW decreased (quadratic, P < 0.05), driven by decreased (quadratic, P < 0.01) ADFI and poorer (quadratic; P < 0.05) G:F. At both 1.5 and 3 mg/kg DON, reductions in ADG were most marked from d 0 to 7 (15 to 22% lower) and were least distinct from d 14 to 21 (5 to 6% lower). Incorporating AMMC at increasing levels had no effect on ADG, ADFI, G:F, or final BW. Overall, these experiments reinforce DON effects on feed intake but also indicate that the effects of DON on G: F may be more severe than previously thought. Furthermore, some pigs appear to develop tolerance to DON, as effects on ADFI and G: F lessen over time. However, the addition of AMMC did not offset the deleterious effects of DON

    Effects of PepSoyGen processing method on nursery pig growth performance

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    Swine Industry Day, 2014 is known as Swine Day, 2014A total of 292 weanling pigs (PIC 327 × 1050; 13.3 ± 2.4 lb BW and 21 d of age) were used in a 31-d experiment evaluating the effects of alternative PepSoyGen processing methods for nursery pig diets. There were 11 replicate pens per treatment and 6 or 7 pigs per pen. At weaning, pigs were allotted to pens by initial weight to 1 of 4 treatments in a completely randomized design. A 3-phase diet series was used with treatment diets fed during Phase 1 (d 0 to 7) and Phase 2 (d 7 to 21), with a common diet fed from d 21 to 31. Diets were: (1) negative control (corn, soybean meal, and dried whey), (2) positive control (4% DPS 50 + 1% PepSoyGen), (3) PepSoyGen processing method 1 (PSG1; 5%), and (4) PepSoyGen processing method 2 (PSG2; 5%). The alternative PepSoyGen processing methods incorporated increasing levels of a proprietary additive post-fermentation (PSG2 > PSG1) aimed at further breakdown of anti-nutritional factors associated with soybean meal. Nutrient analyses generally matched formulated levels for negative and positive control diets, but for both PSG1 and PSG2, CP and amino acid concentrations were lower than formulated, with PSG1 generally 10% lower than PSG2. In Phase 1, pigs fed the positive control diet had improved (P < 0.01) ADG and feed efficiency compared with pigs fed the negative control, whereas pigs fed PSG1 and PSG2 diets were intermediate for feed efficiency but tended (P < 0.07) to have increased ADG compared with those fed the negative control. For Phase 2, there were no significant differences in growth performance between treatment diets. For the overall experimental period (d 0 to 21), pigs fed the positive control diet and PSG2 diet had improved ADG (P < 0.05), whereas pigs fed the positive control, PSG1, and PSG2 diets had improved feed efficiency (P < 0.05) compared with pigs fed the negative control diet. Also, pigs fed PSG1 tended (P < 0.06) to have lower ADG compared with pigs fed the positive control diet. During the Phase 3 common period, no difference in growth performance was observed. Overall (d 0 to 31), ADG was greater (P < 0.01) for pigs fed the positive control diet and tended to be greater (P < 0.07) for pigs fed diets containing PSG2 than the negative control diet, with pigs fed PSG1 intermediate. In conclusion, pigs fed the PSG1 or PSG2 diets had similar performance to pigs fed the positive control diet. Numerically, the PSG2 diet elicited greater performance than the PSG1 diet, but it is unclear whether this response is reflective of the reduced CP and amino acid content in the PSG1 diet or if the differences in processing method affected growth response

    Effects of potential detoxifying agents on growth performance and deoxynivalenol (DON) urinary balance characteristics of nursery pigs fed DON-contaminated wheat

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    Citation: Frobose, H. L., Stephenson, E. W., Tokach, M. D., DeRouchey, J. M., Woodworth, J. C., Dritz, S. S., & Goodband, R. D. (2017). Effects of potential detoxifying agents on growth performance and deoxynivalenol (DON) urinary balance characteristics of nursery pigs fed DON-contaminated wheat. Journal of Animal Science, 95(1), 327-337. doi:10.2527/jas2016.0664Two experiments were conducted to evaluate potential detoxifying agents on growth of nursery pigs fed deoxynivalenol (DON)-contaminated diets. Naturally DON-contaminated wheat (6 mg/kg) was used to achieve desired DON levels. In a 21-d study, 238 pigs (13.4 +/- 1.8 kg BW) were used in a completely randomized design with a 2 x 2 + 1 factorial arrangement. Diets were: 1) Positive control (PC; < 0.5 mg/kg DON), 2) PC + 1.0% Product V (Nutriquest LLC, Mason City, IA), 3) Negative control (NC; 4.0 mg/kg DON), 4) NC + 1.0% Product V, and 5) NC + 1.0% sodium metabisulfite (SMB; Samirian Chemicals, Campbell, CA). There were 6 or 7 replicate pens/treatment and 7 pigs/pen. Analyzed DON was decreased by 92% when pelleted with SMB, but otherwise matched formulated levels. Overall, a DON x Product V interaction was observed for ADG (P < 0.05) with a tendency for an interaction for ADFI (P < 0.10). As anticipated, DON reduced (P < 0.001) ADG and ADFI, but the interaction was driven by even poorer growth when Product V was added to NC diets. Pigs fed NC diets had 10% poorer G: F (P < 0.001) than PC-fed pigs. Reductions in ADG due to DON were most distinct (50%) during the initial period. Adding SMB to NC diets improved (P < 0.01) ADG, ADFI, and G: F, and improved (P < 0.02) ADG and G: F compared to the PC diet. A urinary balance study was conducted using diets 3 to 5 from Exp. 1 to evaluate Product V and SMB on DON urinary metabolism. A 10 d adaptation was followed by a 7 d collection using 24 barrows in a randomized complete block design. Pigs fed NC + SMB diet had greater urinary DON output (P < 0.05) than pigs fed NC + Product V, with NC pigs intermediate. Daily DON excretion was lowest (P < 0.05) in the NC + SMB pigs. However, degradation of DON-sulfonate back to the parent DON molecule was observed as pigs fed NC + SMB excreted more DON than they consumed (164% of daily DON intake), greater (P < 0.001) than pigs fed the NC (59%) or NC + Product V (48%). Overall, Product V did not alleviate DON effects on growth nor did it reduce DON absorption and excretion. However, hydrothermally processing DON-contaminated diets with 1.0% SMB restored ADFI and improved G: F. Even so, the urinary balance experiment revealed that some of the converted DON-sulfonate can degrade back to DON under physiological conditions. While further research is needed to discern the stability of the DON-sulfonate, SMB appears promising to restore performance in pelleted DON-contaminated diets
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