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排序方式: 共有431条查询结果,搜索用时 218 毫秒
1.
E.A. Horst S.K. Kvidera E.J. Mayorga C.S. Shouse M. Al-Qaisi M.J. Dickson J. Ydstie H.A. Ramirez Ramirez A.F. Keating D.J. Dickson K.E. Griswold L.H. Baumgard 《Journal of dairy science》2018,101(6):5515-5530
Activated immune cells are insulin sensitive and utilize copious amounts of glucose. Because chromium (Cr) increases insulin sensitivity and may be immunomodulatory, our objective was to evaluate the effect of supplemental Cr (KemTrace Cr propionate, 20 g/d; Kemin Industries Inc., Des Moines, IA) on immune system glucose utilization and immune system dynamics following an intravenous endotoxin challenge in lactating Holstein cows. Twenty cows (320 ± 18 d in milk) were randomly assigned to 1 of 4 treatments: (1) pair-fed (PF) control (PF-CON; 5 mL of saline; n = 5), (2) PF and Cr supplemented (PF-Cr; 5 mL of saline; n = 5), (3) lipopolysaccharide (LPS)-euglycemic clamp and control supplemented (LPS-CON; 0.375 µg/kg of body weight LPS; n = 5), and (4) LPS-euglycemic clamp and Cr supplemented (LPS-Cr; 0.375 µg/kg of body weight LPS; n = 5). The experiment was conducted serially in 3 periods (P). During P1 (3 d), cows received their respective dietary treatments and baseline values were obtained. At the initiation of P2 (2 d), either a 12-h LPS-euglycemic clamp was conducted or cows were PF to their respective dietary counterparts. During P3 (3 d), cows consumed feed ad libitum and continued to receive their respective dietary treatment. During P2, LPS administration decreased dry matter intake (DMI; 40%) similarly among diets, and by experimental design the pattern and magnitude of reduced DMI were similar in the PF cohorts. During P3, LPS-Cr cows tended to have decreased DMI (6%) relative to LPS-CON cows. Relative to controls, milk yield from LPS-challenged cows decreased (58%) during P2 and LPS-Cr cows produced less (16%) milk than LPS-CON cows. During P3, milk yield progressively increased similarly in LPS-administered cows, but overall milk yield remained decreased (24%) compared with PF controls. There were no dietary treatment differences in milk yield during P3. Circulating insulin increased 9- and 15-fold in LPS-administered cows at 6 and 12 h postbolus, respectively, compared with PF controls. Compared with LPS-CON cows, circulating insulin in LPS-Cr cows was decreased (48%) at 6 h postbolus. Relative to PF cows, circulating LPS binding protein and serum amyloid A from LPS-administered cows increased 2- and 5-fold, respectively. Compared with PF cows, blood neutrophil counts in LPS-infused cows initially decreased, then gradually increased 163%. Between 18 and 48 h postbolus, the number of neutrophils was increased (12%) in LPS-Cr versus LPS-CON cows. The 12-h total glucose deficit was 220 and 1,777 g for the PF and LPS treatments, respectively, but glucose utilization following immune activation was not influenced by Cr. In summary, supplemental Cr reduced the insulin response and increased circulating neutrophils following an LPS challenge but did not appear to alter the immune system's glucose requirement following acute and intense activation. 相似文献
2.
In this study, we compare the effect of twin-screw extrusion processing on the attrition of wood fibers (WFs) with glass fiber. The effects of process variables and screw design on fiber length were investigated by performing a range of dead-stop experiments where the extruder was stopped, opened-up, and compound removed from the screw elements. Fibers, chemically extracted from the polypropylene matrix, were analyzed for length and width using a commercial fiber analyzer. It was found that WF length attrition and composite properties were less affected by screw design and twin-screw processing conditions (feed rate and screw speed) than glass fiber. Length weighted fiber length and X50 length (a measure used in particle size analysis) were equally correlated with process conditions and composite performance for both fiber types. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48551. 相似文献
3.
The effect of exposure to employees from mining and milling operations in a uranium mine on lead isotopes--a pilot study 总被引:1,自引:0,他引:1
Potential exposure during mining and milling of uranium ore has resulted in the industry being highly regulated. Exposure can arise from inhalation of the daughter product radioactive gas radon (222Rn), inhalation of radioactive dust particles from mining and milling, direct irradiation from outside the body, and ingestion of radionuclides (e.g. uranium or radium) in food or water. Making use of the highly unusual lead isotopic signature for uranium ores (high 206Pb/204Pb from the high uranium content, low 208Pb/204Pb from the low Th/U ratio), we undertook a pilot study of nine male mine employees and three controls from the Ranger uranium mine in the Northern Territory Australia to determine if it was feasible to use lead isotopes in blood to identify exposure to uranium-derived materials. The lead isotopic data for the mine employees and controls plot in two distinct fields which are consistent with predicted isotopic patterns. Assuming retention of 10% of the ingested lead, then the increases seen in 206Pb represent intakes of between 0.9 and 15 mg, integrated over the years of exposure. The small amount of lead does not affect blood lead concentrations, but appears to be sufficient to be detectable with sensitive isotopic methods. Further studies, including those on urine, should be undertaken to confirm the veracity of the lead isotope method in monitoring exposure of uranium industry employees. 相似文献
4.
Dickson Joanne M.; Moberly Nicholas J.; Kinderman Peter 《Canadian Metallurgical Quarterly》2011,120(4):975
Despite its theoretical importance, personal goal motivation has rarely been examined in clinical depression. Here we investigate whether clinically depressed persons (n = 23) differ from never-depressed persons (n = 26) on number of freely generated approach and avoidance goals, appraisals of these goals, and reasons why these goals would and would not be achieved. Participants listed approach and avoidance goals separately and generated explanations for why they would (pro) and would not (con) achieve their most important approach and avoidance goals, before rating the importance, likelihood, and perceived control of goal outcomes. Counter to hypothesis, depressed persons did not differ from never-depressed controls on number of approach or avoidance goals, or on the perceived importance of these goals. However, compared to never-depressed controls, depressed individuals gave lower likelihood judgments for desirable approach goal outcomes, tended to give higher likelihood judgments for undesirable to-be-avoided goal outcomes, and gave lower ratings of their control over goal outcomes. Furthermore, although controls generated significantly more pro than con reasons for goal achievement, depressed participants did not. These results suggest that depressed persons do not lack valued goals but are more pessimistic about their likelihood, controllability, and reasons for successful goal attainment. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
5.
6.
S.K. Kvidera M.J. Dickson M. Abuajamieh D.B. Snider M. V. Sanz Fernandez J.S. Johnson A.F. Keating P.J. Gorden H.B. Green K.M. Schoenberg L.H. Baumgard 《Journal of dairy science》2017,100(5):4113-4127
Study objectives were to evaluate the effects of intentionally reduced intestinal barrier function on productivity, metabolism, and inflammatory indices in otherwise healthy dairy cows. Fourteen lactating Holstein cows (parity 2.6 ± 0.3; 117 ± 18 d in milk) were enrolled in 2 experimental periods. Period 1 (5 d) served as the baseline for period 2 (7 d), during which cows received 1 of 2 i.v. treatments twice per day: sterile saline or a gamma-secretase inhibitor (GSI; 1.5 mg/kg of body weight). Gamma-secretase inhibitors reduce intestinal barrier function by inhibiting crypt cell differentiation into absorptive enterocytes. During period 2, control cows receiving sterile saline were pair-fed (PF) to the GSI-treated cows, and all cows were killed at the end of period 2. Administering GSI increased goblet cell area 218, 70, and 28% in jejunum, ileum, and colon, respectively. In the jejunum, GSI-treated cows had increased crypt depth and reduced villus height, villus height-to-crypt depth ratio, cell proliferation, and mucosal surface area. Plasma lipopolysaccharide binding protein increased with time, and tended to be increased 42% in GSI-treated cows relative to PF controls on d 5 to 7. Circulating haptoglobin and serum amyloid A concentrations increased (585- and 4.4-fold, respectively) similarly in both treatments. Administering GSI progressively reduced dry matter intake (66%) and, by design, the pattern and magnitude of decreased nutrient intake was similar in PF controls. A similar progressive decrease (42%) in milk yield occurred in both treatments, but we observed no treatment effects on milk components. Cows treated with GSI tended to have increased plasma insulin (68%) and decreased circulating nonesterified fatty acids (29%) compared with PF cows. For both treatments, plasma glucose decreased with time while β-hydroxybutyrate progressively increased. Liver triglycerides increased 221% from period 1 to sacrifice in both treatments. No differences were detected in liver weight, liver moisture, or body weight change. Intentionally compromising intestinal barrier function caused inflammation, altered metabolism, and markedly reduced feed intake and milk yield. Further, we demonstrated that progressive feed reduction appeared to cause leaky gut and inflammation. 相似文献
7.
Dickson K. W. Chiu Drake T. T. Lin Eleanna Kafeza Minhong Wang Haiyang Hu Hua Hu Yi Zhuang 《Information Systems Frontiers》2010,12(1):29-47
When a disaster occurs, timely actions in response to urgent requests conveyed by critical messages (known as alerts) constitute
a vital key to effectiveness. These actions include notifying potentially affected parties so that they can take precautionary
measures, gathering additional information, and requesting remedial actions and resource allocation. However, there are different
types of disasters such as epidemic outbreaks, natural disasters, major accidents, and terrorist attacks. At the same time,
there are also many different parties involved such as governments, healthcare institutions, businesses, and individuals.
To address these problems, we introduce a Disaster Notification and Resource Allocation System (DNRAS) based on an Alert Management
System (AMS) implemented through Web services. This unified platform supports timely interactions among various parties, focusing
on notification and monitoring, resource enquiry and allocation, as well as the mobility of information. We detail the mechanisms
of these functions in our system, illustrating the Web services interface parameters for communications and interoperability.
We illustrate the applicability of our approach with an example of an epidemic outbreak and discuss the advantage of our approach
with respect to various stakeholders of our system. 相似文献
8.
利用两种等通道角挤压(ECAP)方法(普通单步ECAP和两步ECAP)制备细晶ZK60合金。采用金相显微镜、扫描电镜、透射电镜和X射线衍射仪对合金的组织和织构进行观察,通过拉伸试验研究不同ECAP方法对合金力学性能的影响。结果表明:与单步ECAP变形相比,两步ECAP变形,由于降低了变形温度,晶粒细化效果更好;经过(240℃,4道次)+(180℃,4道次)两步ECAP变形后,合金晶粒细化至约0.8μm;合金的力学性能与材料的织构密切相关,由于存在织构软化效应,与挤压态相比,经单步ECAP变形后合金的强度有所降低,而伸长率明显提高;但经两步ECAP变形后,由于细晶强化和亚结构强化的作用,合金的强度得到提高。 相似文献
9.
In positive social contexts, both adults and older infants show more Duchenne smiling (which involves high cheek raising) than non-Duchenne smiling (which does not). This study compared Duchenne and non-Duchenne smiles in early infancy for clues to their emotional significance. Infants (N?=?13) from 1 to 6 months of age were videotaped weekly for 5 min in 208 face-to-face interactions with their mothers. Levels of Duchenne and non-Duchenne smiling were correlated within interactive sessions, and the 2 smiles had similar developmental trajectories. Duchenne smiles were typically preceded by non-Duchenne smiles. The results suggest these frequently contrasted types of smiles occur in similar situations and are often different temporal phases of a continuous emotional process. In contrast to adults, infant Duchenne smiles had longer durations than non-Duchenne smiles, suggesting infant smiling does not fit adult models of emotional functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
The effects of grain size and environment on creep crack growth (CCG) in Ni-base superalloy, UDIMET 520, were studied through
experiments at 540 °C. Specially designed solution and aging treatments were used to produce γ′ strengthened microstructures with different grain sizes but without any M23C6 grain boundary precipitates. Five grain sizes, which fall into three groups (i.e., small, medium, and large), were employed. The creep crack growth rates (CCGRs) in specimens with small grain sizes were
approximately 2.5 times lower than those with medium and large grain sizes, as a result of crack branching and the presence
of some undissolved primary MC carbides at the grain boundaries. Otherwise, the CCGRs were insensitive to the grain size.
Fractographic observations on the fracture surfaces and metallographic examinations on the cross sections of the interrupted
CCG specimen revealed intergranular microcracks and a faceted intergranular mode of fracture in both air and argon environments.
The test results suggest that the formation and propagation of intergranular cracks by grain boundary sliding (GBS) is the
main micromechanism responsible for CCG in both air and argon environments at the relatively low test temperature employed.
Grain boundary oxidation attack in the air environment simply accelerates the crack growth process. The present results are
in agreement with the theoretical predictions of the GBS-controlled CCG model previously developed by the authors. 相似文献