Experimental study for elastic deformation under isolated footing

The results of field studies of elastic deformations in the footing base, composed of loses soils. Elastic deformation is the result of compression partially bound water at the contacts between the mineral particles, the value of which depends on the wetness soil environment. It was found that deformation depends on the molecular moisture capacity of the soil while elastic settlement increases in proportion to pressure

Studying the impact of geosynthetic materials on the strain-stress state of soil structures applicable to the mechanics of granular media

In the modern construction industry, a solution being successfully proven is the use of geosynthetic materials, applied as semi-holders, to increase the reliability and stability of soil structures. In connection therewith, solving the issues of expanding the range of methods and approaches to predicting the behavior of such structures under the activity of surface loads is a relevant task, since this is a vital factor in evaluating the designing arrangements made, including the use of geosynthetic materials. The aim of the studies according to this paper is to expand the pertinence of the mechanics of granular media (MGM) in order to assess the reliability of decisions made in the design of soil structures from pitifully durable soils, supported with geosynthetic materials, by comparing the obtained values with the results of full-scale tests and the values obtained by the limited component strategy. For this purpose, the paper presents a comparative analysis for the results of determining vertical stresses under the bridge reinforced with geosynthetic materials and its displacement, obtained by the mechanics of granular media and the limited component strategy. The results of laboratory tests, performed in a soil tray, were taken as verification data. The actual values of vertical stresses were determined using soil pressure sensors, and the values of displacement were determined using the movement indicator of the clockwork installed on the deflection meter of a die unit. An approach to determining displacement of a reinforced bridge using the mechanics of granular media was presented for the first time. The newly presented approach to determining displacement of an bridge, reinforced at the base with geosynthetic materials, allows us to conclude on its reliability, which significantly expands the applicability of the MGM as an alternative to the use of the limited component strategy. The aftereffects of contrasting the upsides of vertical anxieties under the bridge reinforced with geosynthetic materials and its displacement, utilizing the Plaxis programming bundle and the MGM dependencies, counting when contrasted and the consequences of lab tests, are presented. Based on the results obtained, a general conclusion was made on the possibility to use the MGM dependencies in deciding the example of the pressure dispersion and the values of displacement of reinforced bridges under the action of surface loads. The paper also discloses the promising directions of research in this area of geotechnical engineering

Effect of Sand Percentage on the Compaction Properties and Undrained Shear Strength of Low Plasticity Clay

This paper investigates the influence of sand content on the mechanical behavior of a low plasticity clay that collected from south of Iraq (Sumer town). Samples have been prepared with sand contents of 0%, 10%, 20%, 30%, and 40% of the clay weight. Standard Proctor and unconfined compression tests have been carried out and the optimum moisture content, maximum dry density, and undrained shear strength have been determined. The results show a gradual increasing trend of the maximum dry density with the increase of the sand content up to 30%. The highest dry density reaches 1.90 g/cm3 corresponding to an optimum moisture content of 12%. In addition, this paper shows that the undrained shear strength is inversely proportional to the increase of the percentage of sand. The results of this work provide a useful addition to the literature regarding the behaviour or low plasticity clay-sand mixture

Эффективность демпфирования поверхностных волн в грунте при помощи инерционных плит переменной жесткости

Выполнено численное моделирование методом конечных элементов процессов демпфирования колебаний, распространяющихся в верхней толще грунтовой среды за счет размещения на пути их распространения барьеров в виде инерционных плит, выполненных из бетона. Рассмотрено несколько расчетных схем барьеров с различной конфигурацией их попе-речных сечений при равном объеме бетона. Выявлены наиболее эффективные конструктивные решения. В качестве критерия эффективности принято относительное снижение вертикальных колебаний поверхности грунта за барьером

Endogenous spartin (SPG20) is recruited to endosomes and lipid droplets and interacts with the ubiquitin E3 ligases AIP4 and AIP5

The HSPs (hereditary spastic paraplegias) are genetic conditions in which there is distal degeneration of the longest axons of the corticospinal tract, resulting in spastic paralysis of the legs. The gene encoding spartin is mutated in Troyer syndrome, an HSP in which paralysis is accompanied by additional clinical features. There has been controversy over the subcellular distribution of spartin. We show here that, at steady state, endogenous spartin exists in a cytosolic pool that can be recruited to endosomes and to lipid droplets. Cytosolic endogenous spartin is mono-ubiquitinated and we demonstrate that it interacts via a PPXY motif with the ubiquitin E3 ligases AIP4 [atrophin-interacting protein 4; WWP2 (WW domain-containing E3 ubiquitin protein ligase 2] and AIP5 (WWP1). Surprisingly, the PPXY motif, AIP4 and AIP5 are not required for spartin's ubiquitination, and so we propose that spartin acts as an adaptor for these proteins. Our results suggest that spartin is involved in diverse cellular functions, which may be of relevance to the complex phenotype seen in Troyer syndrome

A role for ubiquitin ligases and Spartin/SPG20 in lipid droplet turnover

HECT (homologous to the E6AP C terminus) ubiquitin ligases have diverse functions in eukaryotic cells. In screens for proteins that bind to the HECT ubiquitin ligase WWP1, we identified Spartin, which is also known as SPG20. This protein is truncated in a neurological disease, Troyer syndrome. In this study, we show that SPG20 associates with the surface of lipid droplets (LDs) and can regulate their size and number. SPG20 binds to another LD protein, TIP47, and both proteins compete with an additional LD protein, adipophilin/adipocyte differentiation-related protein, for occupancy of LDs. The mutant SPG20 present in Troyer syndrome does not possess these activities. Depletion of SPG20 using RNA interference increases the number and size of LDs when cells are fed with oleic acid. Binding of WWP1 to SPG20 and the consequent ubiquitin transfer remove SPG20 from LDs and reduce the levels of coexpressed SPG20. These experiments suggest functions for ubiquitin ligases and SPG20 in the regulation of LD turnover and potential pathological mechanisms in Troyer syndrome

SPG20 Protein Spartin Associates with Cardiolipin via Its Plant-Related Senescence Domain and Regulates Mitochondrial Ca2+ Homeostasis

Hereditary spastic paraplegias (HSPs) are a group of neurological disorders characterized clinically by spasticity of lower limbs and pathologically by degeneration of the corticospinal tract. Troyer syndrome is an autosomal recessive HSP caused by a frameshift mutation in the spartin (SPG20) gene. Previously, we established that this mutation results in a lack of expression of the truncated mutant spartin protein. Spartin is involved in many cellular processes and associates with several intracellular organelles, including mitochondria. Spartin contains a conserved plant-related senescence domain at its C-terminus. However, neither the function of this domain nor the roles of spartin in mitochondrial physiology are currently known. In this study, we determined that the plant-related senescence domain of spartin interacts with cardiolipin but not with two other major mitochondrial phospholipids, phosphatidylcholine and phosphatidylethanolamine. We also found that knockdown of spartin by small interfering RNA in a human neuroblastoma cell line resulted in depolarization of the mitochondrial membrane. In addition, depletion of spartin resulted in a significant decrease in both mitochondrial calcium uptake and mitochondrial membrane potential in cells treated with thapsigargin. Our results suggest that impairment of mitochondrial calcium uptake might contribute to the neurodegeneration of long corticospinal axons and the pathophysiology of Troyer syndrome