1,114 research outputs found
Energy and Nutrient Intake Monitoring
A passive system to determine the in-flight intake of nutrients is developed. Nonabsorbed markers placed in all foods in proportion to the nutrients selected for study are analyzed by neutron activation analysis. Fecal analysis for each market indicates how much of the nutrients were eaten and apparent digestibility. Results of feasibility tests in rats, mice, and monkeys indicate the diurnal variation of several markers, the transit time for markers in the alimentary tract, the recovery of several markers, and satisfactory use of selected markers to provide indirect measurement of apparent digestibility. Recommendations are provided for human feasibility studies
Navigation by satellite using two-way range and doppler data
Navigation by satellite using two-way range and Doppler dat
Dynamics of Sprung Loads on Pavements
The attached report, Dynamics of Sprung Loads on Pavements, resulted from a need for reliable impact factors for use in the structural design of pavements. For some years, it has been customary to use 1.2 times the static wheel load for designing portland cement concrete pavements. We, along with other investigators, have questioned this value, and have actually used higher values for some specific conditions. Impact factors for specific situations are listed on page 33 of the report. The three roads classed as smooth averaged 1.25, while the rough road gave a value of 1.35. Depressions at culverts and bridge approaches gave average values of 1.58 and 1.49 respectively. It appears that pavement design impact factors of 1.20 are too low and should be in the order of 1.33 to 1.50
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Small entities with large impact: microcalcifications and atherosclerotic plaque vulnerability
Purpose of review Atherosclerotic plaque rupture and subsequent acute events, such as myocardial infarction and stroke, contribute to the majority of cardiovascular-related deaths. Calcification has emerged as a significant predictor of cardiovascular morbidity and mortality, challenging previously held notions that calcifications stabilize atherosclerotic plaques. In this review, we address this discrepancy through recent findings that not all calcifications are equivalent in determining plaque stability. Recent findings The risk associated with calcification is inversely associated with calcification density. As opposed to large calcifications that potentially stabilize the plaque, biomechanical modeling indicates that small microcalcifications within the plaque fibrous cap can lead to sufficient stress accumulation to cause plaque rupture. Microcalcifications appear to derive from matrix vesicles enriched in calcium-binding proteins that are released by cells within the plaque. Clinical detection of microcalcifications has been hampered by the lack of imaging resolution required for in-vivo visualization; however, recent studies have demonstrated promising new techniques to predict the presence of microcalcifications. Summary Microcalcifications play a major role in destabilizing atherosclerotic plaques. The identification of critical characteristics that lead to instability along with new imaging modalities to detect their presence in vivo may allow early identification and prevention of acute cardiovascular events
An ultrastructural study of spermiogenesis in the normal (Rock) and male producing strains of the mosquito Aedes aegypti.
Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1972 .H96. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.Sc.)--University of Windsor (Canada), 1972
Fulvestrant-induced expression of erbB3 and erbB4 sensitizes ER-positive breast cancer cells to heregulins
We have previously reported that induction of EGFR and erbB2 in response to antihormones may provide an early mechanism allowing breast cancer cells to evade the growth inhibitory action of such therapies and ultimately drive resistant growth. More recently, another member of the erbB receptor family, erbB3, has been implicated in antihormone resistance in breast cancer. In the present study we have investigated whether induction of erbB3, and related family member erbB4, may provide an alternative resistance mechanism to antihormonal action in a panel of four ER-positive breast cancer cell lines. MCF-7, T47D, BT474 and MDAMB361 cell lines were exposed to fulvestrant (100 nM) for 7 days, and effects on erbB3/4 signalling and growth were assessed. Effects of the erbB3/4 ligand heregulin-β1 were also examined in the absence and presence of fulvestrant. Fulvestrant potently reduced ER expression and transcriptional activity and significantly inhibited growth in all four cell lines. However, alongside this inhibitory activity, fulvestrant also consistently induced protein expression and activity of erbB4 in the four cell lines and also promoted erbB3, erbB2 and EGFR protein expression and activity in MCF-7 and T47D cells. Consequently, fulvestrant treatment sensitised each cell line to the actions of heregulin-β1 with enhanced erbB3/4-driven signalling activity and significant increases in cell proliferation being observed when compared with untreated cells. Indeed, in T47D and MDAMB361, heregulin-β1 was converted from a ligand having negligible or suppressive growth activity into one that potently promoted cell proliferation. Consequently, fulvestrant-induced growth inhibition was completely overridden by heregulin-β1 in all four cell lines. In conclusion, these findings would suggest that although antihormones, such as fulvestrant, may have potent acute growth inhibitory activity in ER-positive breast cancer cells, their ability to induce and sensitize cells to growth factors, such as heregulins, may serve to reduce and ultimately limit their inhibitory activity
Influence of Level of Daily Supplement Intake on Performance of Calves Grazing Rye-Ryegrass Pastures
Last updated: 6/1/200
Ablation debris control by means of closed thick film filtered water immersion
The performance of laser ablation generated debris control by means of open immersion techniques have been shown to be limited by flow surface ripple effects on the beam and the action of ablation plume pressure loss by splashing of the immersion fluid. To eradicate these issues a closed technique has been developed which ensured a controlled geometry for both the optical interfaces of the flowing liquid film. This had the action of preventing splashing, ensuring repeatable machining conditions and allowed for control of liquid flow velocity. To investigate the performance benefits of this closed immersion technique bisphenol A polycarbonate samples have been machined using filtered water at a number of flow velocities. The results demonstrate the efficacy of the closed immersion technique: a 93% decrease in debris is produced when machining under closed filtered water immersion; the average debris particle size becomes larger, with an equal proportion of small and medium sized debris being produced when laser machining under closed flowing filtered water immersion; large debris is shown to be displaced further by a given flow velocity than smaller debris, showing that the action of flow turbulence in the duct has more impact on smaller debris. Low flow velocities were found to be less effective at controlling the positional trend of deposition of laser ablation generated debris than high flow velocities; but, use of excessive flow velocities resulted in turbulence motivated deposition. This work is of interest to the laser micromachining community and may aide in the manufacture of 2.5D laser etched patterns covering large area wafers and could be applied to a range of wavelengths and laser types
Evaluation of Cattle-ASE?äó on Gain of Yearling Heifers Grazing Bermudagrass
Last updated: 6/12/200
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