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101.
Ultimate load capacity of slender injection piles in soft soils. Small diameter driven injection piles are applied as a low cost foundation element for many years. They reach extremly high slenderness and tend to buckling behaviour. Some recent damage cases show that the bearing capacity is frequently overestimated. The design codes do not give evidences for the estimation of the ultimate load capacity in detail. The purpose of this paper is to show a practical method of analysis which includes the essential input parameters of apparent cohesion intercept and pile imperfection as well as the elastoplastic properties of pile material and soil. 相似文献
102.
David E. Hogan Fei Tian Scott W. Malm Laurel L. Kegel Lajos Z Szabó Anoop S. Hunjan Jeanne E. Pemberton Walter T. Klimecki Robin Polt Raina M. Maier 《Journal of surfactants and detergents》2020,23(4):715-724
In 2014, almost 16 million tons of surfactants were used globally for cleaning and industrial applications. As a result, massive quantities disperse into environmental compartments every day. There is great market interest in developing highly biodegradable, less-toxic, and renewable alternatives to currently used petroleum-based surfactants. Glycolipid surfactants, composed of a sugar headgroup and lipid tail, are effective surfactants and emulsifiers with a high tolerance to electrolytes and are easily tailored to address specific needs. The green synthesis and surfactant characteristics of a suite of cellobiosides and melibiosides were recently described. The biodegradability and toxicity of 1°-alkyl-O-cellobiosides, 2°-alkyl-O-cellobiosides, and 1°-alkyl-O-melibiosides with straight-chain alkyl tails of 8, 10, and 12 are reported in this study. Biodegradability was assessed by quantifying mineralization (CO2 evolution). All of the glycosides were inherently biodegradable and most were readily biodegradable according to OECD and US environmental protection agency (EPA) definitions. The Microtox acute toxicity assay showed both chain length and headgroup had significant effects on toxicity, but most of the molecules were practically nontoxic according to EPA definitions with EC50 values >100 mg L−1. Cytotoxicity to human lung (H1299) and keratinocyte cell lines (HaCaT) was measured by xCELLigence and MTS assays. Cytotoxicity values were comparable to similar glycosides previously reported. IC50 values were determined but in general, exceeded surfactant concentrations that are found in the environment. These data demonstrate the promising nature of these molecules as green alternatives to petrochemical surfactants. 相似文献
103.
Soils collected in 2004 along two North American continental-scale transects were subjected to geochemical and mineralogical analyses. In previous interpretations of these analyses, data were expressed in weight percent and parts per million, and thus were subject to the effect of the constant-sum phenomenon. In a new approach to the data, this effect was removed by using centered log-ratio transformations to ‘open’ the mineralogical and geochemical arrays. Multivariate analyses, including principal component and linear discriminant analyses, of the centered log-ratio data reveal the effects of soil-forming processes, including soil parent material, weathering, and soil age, at the continental-scale of the data arrays that were not readily apparent in the more conventionally presented data. Linear discriminant analysis of the data arrays indicates that the majority of the soil samples collected along the transects can be more successfully classified with Level 1 ecological regional-scale classification by the soil geochemistry than soil mineralogy. A primary objective of this study is to discover and describe, in a parsimonious way, geochemical processes that are both independent and inter-dependent and manifested through compositional data including estimates of the elements and corresponding mineralogy. 相似文献
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106.
Characterization of zinc, lead, and cadmium in mine waste: implications for transport, exposure, and bioavailability 总被引:4,自引:0,他引:4
Schaider LA Senn DB Brabander DJ McCarthy KD Shine JP 《Environmental science & technology》2007,41(11):4164-4171
We characterized the lability and bioaccessibility of Zn, Pb, and Cd in size-fractionated mine waste at the Tar Creek Superfund Site (Oklahoma) to assess the potential for metal transport, exposure, and subsequent bioavailability. Bulk mine waste samples contained elevated Zn (9100 +/- 2500 ppm), Pb (650 +/- 360 ppm), and Cd (42 +/- 10 ppm), while particles with the greatest potential for windborne transport and inhalation (< 10 microm) contained substantially higher concentrations, up to 220 000 ppm Zn, 16 000 ppm Pb, and 530 ppm Cd in particles < 1 microm. Although the mined ore at Tar Creek primarily consisted of refractory metal sulfides with low bioavailability, sequential extractions and physiologically based extractions indicate that physical and chemical weathering have shifted metals into relatively labile and bioaccessible mineral phases. In < 37 microm mine waste particles, 50-65% of Zn, Pb, and Cd were present in the "exchangeable" and "carbonate" sequential extraction fractions, and 60-80% of Zn, Pb, and Cd were mobilized in synthetic gastric fluid, while ZnS and PbS exhibited minimal solubility in these solutions. Our results demonstrate the importance of site-specific characterization of size-fractionated contemporary mine waste when assessing the lability and bioavailability of metals at mine-waste impacted sites. 相似文献
107.
RJ Gralla RM Navari PJ Hesketh W Popovic J Strupp J Noy L Einhorn D Ettinger W Bushnell C Friedman 《Canadian Metallurgical Quarterly》1998,16(4):1568-1573
Insights into structure-function relations of many proteins opens the possibility of engineering peptides to selectively interfere with a protein's activity. To facilitate the use of peptides as probes of cellular processes, we have developed caged peptides whose influence on specific proteins can be suddenly and uniformly changed by near-UV light. Two peptides are described which, on photolysis of a caging moiety, block the action of calcium-calmodulin or myosin light chain kinase (MLCK). The efficacy of theses peptides is demonstrated in vitro and in vivo by determining their effect before and after photolysis on activities of isolated enzymes and cellular functions known to depend on calcium-calmodulin and MLCK. These caged peptides each were injected into motile, polarized eosinophils, and when exposed to light promptly blocked cell locomotion in a similar manner. The results indicate that the action of calcium-calmodulin and MLCK, and by inference myosin II, are required for the ameboid locomotion of these cells. This methodology provides a powerful means for assessing the role of these and other proteins in a wide range of spatio-temporally complex functions in intact living cells. 相似文献
108.
R Ettinger R Mebius JL Browning SA Michie S van Tuijl G Kraal W van Ewijk HO McDevitt 《Canadian Metallurgical Quarterly》1998,10(6):727-741
Previously, we have reported that neutralization of surface lymphotoxin (LT-alphabeta) in mice which expressed an LT-beta receptor-Fc fusion protein, driven by the cytomegalovirus promoter, resulted in an array of anatomic abnormalities. We now report that mice which express a tumor necrosis factor (TNF) receptor p60-Fc fusion protein (which neutralizes TNF and soluble LT-alpha3 activity) develop unique lymphoid abnormalities. Our data demonstrate that some aspects of peripheral lymphoid organ development require both surface LT-alphabeta and TNF interacting with their specific receptors. However, these related cytokines are also capable of signaling distinct developmental events. Splenic MAdCAM-1 expression, follicular dendritic cell localization and normal Peyer's patch development all require both surface LT-alphabeta and TNF activity. Marginal zone formation and splenic B cell localization primarily require surface LT-alphabeta-LT-beta receptor interactions. Primary follicle formation was dependent upon TNF receptor(s) engagement. Interestingly spleen, lymph nodes and Peyer's patches from TNF receptor p60-Fc-expressing mice all develop different abnormalities, suggesting distinct pathways of development in these lymphoid organs. Thymus development appears to be independent of these signaling pathways. These results demonstrate that TNF and LT are crucial for normal peripheral, but not central lymphoid organ development. 相似文献
109.
Barnett David W.; Bell Susan H.; Bauer Annie; Lentz Francis E. Jr.; Petrelli Sabrina; Air Amy; Hannum Laurel; Ehrhardt Kristal E.; Peters Cynthia A.; Barnhouse Lisa; Reifin Linda H.; Stollar Stephanie 《Canadian Metallurgical Quarterly》1997,12(4):293
Presents the evaluation design and case study outcomes for 28 children (aged 3–5 yrs) from the 1st 3 yrs of the Ohio Early Childhood Intervention (ECI) project. The ECI project was designed to help build the capacity of professionals for intervention design. Capacity building refers to preparing educational systems for change and, specific to this report, providing valid conceptual and procedural guidelines for early intervention. The foundations of the ECI project are ecobehavioral analysis, ecological consultation, and naturalistic intervention design. The acronym PASSKey (Planned Activity, Strategic Sampling, Keystone behavior) describes 3 major aspects of the assessment-intervention guidelines. Validity evidence for the guidelines is based on single case quasi-experimental (accountability and case study) designs documented by comprehensive early childhood case portfolios. In addition, estimates were obtained of the consultants' time spent in problem solving. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
110.
A new allelic series at the underwhite gene is described. Three of the alleles in the series--uw, uwd, and Uwdbr--arose as spontaneous mutations on different genetic backgrounds at The Jackson Laboratory. We report here the visible phenotypes and dominance hierarchy of these alleles, all of which are defined by a reduction of pigmentation in both eye and coat color. Electron microscopic analysis of retinal epithelium suggests that the primary defect is in the melanosome. The degree of severity of melanosome anomalies in the retina correlates with the degree of hypopigmentation in the coat. The perturbed gene and its gene product are unknown. We show that the uw locus is genetically distinct from Myo10, a suggested candidate gene for this mutation. 相似文献