Behaviour of cohesive soils under uplift forces

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Vibrations Due to Pile Driving

Vibrations due to pile installation have long been a concern to owners, contractors, and engineers. Specifically, what levels of vibrations can be assumed for a given pile, hammer, and subsurface conditions and how can these levels be predicted in advance of construction so an assessment of nearby structures can be made? This paper presents the results of vibration monitoring at several sites where various piles and pile hammers have been used, and recommends a conservative method of predicting peak particle velocity at the ground surface near pile installations. Where sensitive structures are involved, a response spectrum analysis is recommended

Comparison of Two Ground Modification Techniques to Reduce Settlement

At the La Rosita Power Plant site in Mexicali, Mexico, a 3-m thick layer of loose very fine sandy silt was encountered at about 7.5 m depth. Settlement calculations performed for the heavier (150 to 200 kPa) settlement sensitive structures indicated values of up to 65 mm, compared to an allowable settlement of 50 mm. During the design of the base plant, various options for limiting settlement were reviewed. Based on a cost and schedule review, jet grouting of the loose silt layer was chosen. The predicted post-grouting foundation settlement was approximately 35 to 40 mm. During construction of the base plant, the owner elected to add an additional unit on an adjacent site that had very similar subsurface conditions. The same ground modification options were again considered for this expansion unit. However, this time removal of a portion of the upper clayey soils and replacement with compacted structural fill materials was chosen as the best option. Computations indicated that removal to a depth of 3 m would reduce the predicted settlement to less than 50mm. Measured settlements on both sites (base plant with jet grouting and expansion plant with soil replacement) were well within predicted limits. A comparison of the settlements showed that the soil replacement was slightly more effective than the jet grouting in these circumstances. One meter of structural fill was required under all structures to prevent shrink-swell of the upper clayey soils. During the jet grouting operation at the base plant, the jet grout spoil materials were used in lieu of structural fill under the cooling tower foundation. At the expansion site, the cooling towers were supported on 1 m of structural fill since no jet grout spoils were available. The measured settlements of these two structures were almost identical, confirming that the jet grouting spoils produced an excellent fill material when properly handled

An integrated analysis of genes and pathways exhibiting metabolic differences between estrogen receptor positive breast cancer cells

<p>Abstract</p> <p>Background</p> <p>The sex hormone estrogen (E2) is pivotal to normal mammary gland growth and differentiation and in breast carcinogenesis. In this <it>in silico </it>study, we examined metabolic differences between ER(+)ve breast cancer cells during E2 deprivation.</p> <p>Methods</p> <p>Public repositories of SAGE and MA gene expression data generated from E2 deprived ER(+)ve breast cancer cell lines, MCF-7 and ZR75-1 were compared with normal breast tissue. We analyzed gene ontology (GO), enrichment, clustering, chromosome localization, and pathway profiles and performed multiple comparisons with cell lines and tumors with different ER status.</p> <p>Results</p> <p>In all GO terms, biological process (BP), molecular function (MF), and cellular component (CC), MCF-7 had higher gene utilization than ZR75-1. Various analyses showed a down-regulated immune function, an up-regulated protein (ZR75-1) and glucose metabolism (MCF-7). A greater percentage of 77 common genes localized to the q arm of all chromosomes, but in ZR75-1 chromosomes 11, 16, and 19 harbored more overexpressed genes. Despite differences in gene utilization (electron transport, proteasome, glycolysis/gluconeogenesis) and expression (ribosome) in both cells, there was an overall similarity of ZR75-1 with ER(-)ve cell lines and ER(+)ve/ER(-)ve breast tumors.</p> <p>Conclusion</p> <p>This study demonstrates integral metabolic differences may exist within the same cell subtype (luminal A) in representative ER(+)ve cell line models. Selectivity of gene and pathway usage for strategies such as energy requirement minimization, sugar utilization by ZR75-1 contrasted with MCF-7 cells, expressing genes whose protein products require ATP utilization. Such characteristics may impart aggressiveness to ZR75-1 and may be prognostic determinants of ER(+)ve breast tumors.</p

Variation in Capacities of Different Pile Types Under Similar Soil Conditions

The interaction between soil and various pile types is of interest because it depends not only on the shear strength characteristics of the soil, but also on the pile dimensions, shape, and installation method, and on time after pile installation. This paper presents load test results from three types of displacement piles installed at the same site. The results obtained from the tests are compared with theoretical estimates. The computed values of soil-pile adhesion, back-calculated from the load tests, are discussed and compared with values found in the literature. Estimated pile capacities during driving and retap are also compared and discussed

Differential Settlement of Nuclear Power Plant Foundations

A rational approach is presented for evaluating differential settlement of structures at nuclear power plants where settlement monitoring and the associated documentation are important. In nuclear plants, allowable differential settlement is governed by the necessity to prevent architectural and structural damage, equipment malfunction, touching of adjacent buildings during an earthquake, and damage to buried utilities. Measurements of actual settlement of the plant should be taken on a regular basis from start of construction and compared with the allowable values. A description is given of methods for calculating allowable values for differential settlements, and a comprehensive program for obtaining actual settlement data at a nuclear site is outlined. The ratio of measured to allowable differential settlement at which remedial action may be required is discussed. A case history of differential settlements at a nuclear plant is presented. The settlement patterns exhibited by the major structures can be correlated with foundation conditions at the plant site. Measured differential settlements are small, generally less than 0.25 inch, compared with values of allowable differential settlement which are mainly greater than 0.75 inch

Uplift Load Tests on Driven Piles

Details and results of uplift load tests on 25 piles at 15 sites are presented. The allowable uplift load on each pile determined from the BOCA code criterion is compared with an allowable capacity based on small movements at design load. In the majority of cases, the BOCA capacities are significantly lower

Repression of histone H5 gene expression in chicken mature erythrocytes is correlated with reduced DNA-binding activities of transcription factors SP1 and GATA-1

AbstractDuring the final stages of erythroid maturation, the expression of the chicken histone H5 gene ceases. The histone H5 promoter has binding sites for Sp1 and UPE-binding protein. The 3' histone H5 enhancer has binding sites for Sp1, GATA-1 and NF1. Here, we show that the DNA-binding activities of transcription factors Sp1 and GATA-1 is reduced 5- to 10-fold in mature cells, while the activities of UPE-binding protein and NF1 remain the same in mature and immature erythrocytes. The reduced activities of Sp1 and GATA-1 may contribute to the inactivation of the histone H5 gene in mature erythrocytes