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排序方式: 共有386条查询结果,搜索用时 15 毫秒
131.
Congenital and pediatric interstitial lung disease (ILD) is set in the context of the maturing lung and immune system, and thus differs completely from its adult equivalents in presentation, therapy, and outcome. We first establish the background by briefly reviewing normal maturational changes and then describe recent advances in diagnosis. We then highlight three specific topics: drugs and the lung (treatment and iatrogenic ILD); the histiocytic disorders of the lung; and congenital ILD (specifically congenital surfactant protein deficiency). 相似文献
132.
CT Dougherty FW Knapp LP Bush JE Maul J Van Willigen 《Canadian Metallurgical Quarterly》1998,35(5):798-803
Larvae of arthropod ectoparasites of livestock, such as the horn fly, Haematobia irritans (L.), may be exposed to acyl-loline alkaloids in dung of ruminant livestock ingesting herbage of the tall fescue (Festuca arundinacea Schreb.)-endophyte association [Neotyphodium coenophialum (Morgan-Jones & W. Gams) Glenn, Bacon & Hanlin comb. nov.]. Biological activity of alkaloid-supplemented bovine dung was assayed by growth, development, and survival of 1st instars of horn fly. An extract from tall fescue seed, containing N-formyl loline (NFL), N-acetyl loline (NAL), and loline (59:21:20 by mass, respectively) caused 100% mortality of horn fly larvae when dung was supplemented at > or = 100 micrograms/g. Probit analysis of data corrected for natural mortality indicated a LD50 of 30 micrograms/g (95% fidicial limits: 20-49 micrograms/g). When horn fly larvae were introduced to dung supplemented with up to 50 microM of acyl-loline derivatives, mortality of larvae varied significantly between alkaloids (P < 0.0001). Probit analysis indicated that NFL [LD50: 34 microM (95% fidicial limits: 3-53 microM)] was more toxic than NAL [LD50: 46 microM (0-83 microM)], and that loline hydrochloride was not toxic. 相似文献
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135.
An analytic procedure for obtaining variances of estimates of variance components in a general multi-way classification is described. As an application, three methods for estimating variance components are compared for a two-way classification. Since the variances of the estimates are affected by the magnitude of the true variance components (parameters) as well as the arrangement of the subclass numbers (n ij 's), a numerical tabulation is necessary in order to make a comparison. Using a UNIVAC 1105, the variances of the estimates of variance components are evaluated over a substantial range of parameters and n ij 's. These results are presented in tabular form for selected sets of parameter values. 相似文献
136.
Antarctic research bases: local sources of polybrominated diphenyl ether (PBDE) flame retardants 总被引:4,自引:0,他引:4
Hale RC Kim SL Harvey E La Guardia MJ Mainor TM Bush EO Jacobs EM 《Environmental science & technology》2008,42(5):1452-1457
Contemporary studies of chemical contamination in Antarctica commonly focus on remnants of historical local releases or long-range transport of legacy pollutants. To protect the continent's pristine status, the Antarctic Treaty's Protocol on Environmental Protection prohibits importation of persistent organic pollutants. However, some polybrominated diphenyl ether (PBDE) congeners exhibit similar properties. Many modern polymer-containing products, e.g., home/office furnishings and electronics, contain percent levels of flame retardant PBDEs. PBDE concentrations in indoor dust and wastewater sludge from the U.S. McMurdo and New Zealand-operated Scott Antarctic research bases were high. Levels tracked those in sludge and dust from their respective host countries. BDE-209, the major constituent in the commercial deca-PBDE product, was the dominant congener in sludge and dust, as well as aquatic sediments collected near the McMurdo wastewater outfall. The pattern and level of BDE-209 sediment concentrations, in conjunction with its limited environmental mobility, suggest inputs from local sources. PBDE concentrations in fish and invertebrates near the McMurdo outfall rivaled those in urbanized areas of North America and generally decreased with distance. The data indicate that reliance on wastewater maceration alone, as stipulated by the Protocol, may permit entry of substantial amounts of PBDEs and other chemicals to the Antarctic environment. 相似文献
137.
Trenton B. Bush Zahra Khalkhali Victor Champagne David P. Schmidt Jonathan P. Rothstein 《Journal of Thermal Spray Technology》2017,26(7):1548-1564
When a solid, ductile particle impacts a substrate at sufficient velocity, the resulting heat, pressure and plastic deformation can produce bonding between the particle and the substrate. The use of a cool supersonic gas flow to accelerate these solid particles is known as cold spray deposition. The cold spray process has been commercialized for some metallic materials, but further research is required to unlock the exciting potential material properties possible with polymeric particles. In this work, a combined computational and experimental study was employed to study the cold spray deposition of high-density polyethylene powders over a wide range of particle temperatures and impact velocities. Cold spray deposition of polyethylene powders was demonstrated across a range broad range of substrate materials including several different polymer substrates with different moduli, glass and aluminum. A material-dependent window of successful deposition was determined for each substrate as a function of particle temperature and impact velocity. Additionally, a study of deposition efficiency revealed the optimal process parameters for high-density polyethylene powder deposition which yielded a deposition efficiency close to 10% and provided insights into the physical mechanics responsible for bonding while highlighting paths toward future process improvements. 相似文献
138.
Localization of labile posttranslational modifications by electron capture dissociation: the case of gamma-carboxyglutamic acid. 总被引:5,自引:0,他引:5
N L Kelleher R A Zubarev K Bush B Furie B C Furie F W McLafferty C T Walsh 《Analytical chemistry》1999,71(19):4250-4253
Tandem mass spectrometry (MS/MS) of 28 residue peptides harboring gamma-carboxylated glutamic acid residues, a posttranslational modification of several proenzymes of the blood coagulation cascade, using either collisions or infrared photons results in complete ejection of the gamma-CO2 moieties (-44 Da) before cleavage of peptide-backbone bonds. However, MS/MS using electron capture dissociation (ECD) in a Fourier transform mass spectrometer cleaves backbone bonds without ejecting CO2, allowing direct localization of this labile modification. Sulfated side chains are also retained in ECD backbone fragmentations of a 21-mer peptide, although CAD causes extensive SO3 loss. ECD thus is a unique complement to conventional methods for MS/MS, causing less undesirable loss of side-chain functionalities as well as more desirable backbone cleavages. 相似文献
139.
There is a trend toward the use of predictivesystems in communications networks. At the systems andnetwork management level predictive capabilities arefocused on anticipating network faults and performance degradation. Simultaneously, mobilecommunication networks are being developed withpredictive location and tracking mechanisms. Theinteractions and synergies between these systems presenta new set of problems. A new predictive network managementframework is developed and examined. The interactionbetween a predictive mobile network and the proposednetwork management system is discussed. The Rapidly Deployable Radio Network (RDRN) is used as aspecific example to illustrate theseinteractions. 相似文献
140.