Sequestration of the abrin A chain to the nucleus by BASP1 increases the resistance of cells to abrin toxicity

Abrin, a type II ribosome-inactivating protein, comprises A and B subunits wherein the A subunit harbours toxin activity and the B subunit has a galactose-specific lectin activity. The entry of the protein inside the cell is through the binding of the B chain to cell surface glycoproteins followed by receptor-mediated endocytosis and retrograde transport. A previous study from our laboratory showed that different cell lines exhibited differences of as great as similar to 200-fold in abrin toxicity, prompting the present study to compare the trafficking of the toxin within cells. Observations made in this regard revealed that the abrin A chain, after being released into the cytosol, is sequestered into the nucleus through interaction with a cellular protein of similar to 25 kDa, BASP1 (brain acid-soluble protein 1). The nuclear localization of the A chain is seen predominantly in cells that are less sensitive to abrin toxicity and dependent on the levels of BASP1 in cells. The sequestration by BASP1 renders cells increasingly resistant to the inhibition of protein synthesis by abrin and the nucleus act as a sink to overcome cellular stress induced

Vertical Uplift Resistance of Two Interfering Horizontal Anchors in Clay

The vertical uplift resistance of two interfering rigid strip plate anchors embedded horizontally at the same level in clay has been examined. The lower and upper bound theorems of the limit analysis in combination with finite-elements and linear optimization have been employed to compute the failure load in a bound form. The analysis is meant for an undrained condition and it incorporates the increase of cohesion with depth. For different clear spacing (S) between the anchors, the magnitude of the efficiency factor (eta c gamma) resulting from the combined components of soil cohesion (c) and soil unit weight (gamma), has been computed for different values of embedment ratio (H/B), the rate of linear increase of cohesion with depth (m) and normalized unit weight (gamma H/c). The magnitude of eta c gamma has been found to reduce continuously with a decrease in the spacing between the anchors, and the uplift resistance becomes minimum for S/B=0. It has been noted that the critical spacing between the anchors required to eliminate the interference effect increases continuously with (1) an increase in H/B, and (2) a decrease in m.

Vertical Uplift Resistance of Pipes Buried in Sand

By incorporating the variation of peak soil friction angle (phi) with mean principal stress (sigma(m)), the effect of pipe diameter (D) on the vertical uplift resistance of a long horizontal pipeline embedded in sand has been investigated. The analysis has been performed by using the lower bound finite-element limit analysis in combination with nonlinear optimization. Three well-defined phi versus sigma(m) curves reported from literature for different sands have been used. It is observed that for a given embedment ratio, with an increase in pipe diameter, the magnitude of the uplift factor (F-gamma) reduces quite significantly, which indicates the importance of considering scale effects while designing buried pipe lines. The scale effects have been found to become even more substantial with an increase in the embedment ratio. The analysis compares well with various theoretical results reported from literature. On the other hand, as compared to available centrifuge test results, the present analysis has been found to provide quite a higher magnitude of the uplift resistance when the theoretical prediction is based on peak soil friction angle. However, if the theoretical analysis is performed by using the friction angle that accounts for the progressive shear failure, the difference between the theoretical and centrifuge test results decreases quite significantly.(C) 2013 American Society of Civil Engineers.

Reliability-based load and resistance factor design approach for external seismic stability of reinforced soil walls

Load and resistance factor design (LRFD) approach for the design of reinforced soil walls is presented to produce designs with consistent and uniform levels of risk for the whole range of design applications. The evaluation of load and resistance factors for the reinforced soil walls based on reliability theory is presented. A first order reliability method (FORM) is used to determine appropriate ranges for the values of the load and resistance factors. Using pseudo-static limit equilibrium method, analysis is conducted to evaluate the external stability of reinforced soil walls subjected to earthquake loading. The potential failure mechanisms considered in the analysis are sliding failure, eccentricity failure of resultant force (or overturning failure) and bearing capacity failure. The proposed procedure includes the variability associated with reinforced backfill, retained backfill, foundation soil, horizontal seismic acceleration and surcharge load acting on the wall. Partial factors needed to maintain the stability against three modes of failure by targeting component reliability index of 3.0 are obtained for various values of coefficients of variation (COV) of friction angle of backfill and foundation soil, distributed dead load surcharge, cohesion of the foundation soil and horizontal seismic acceleration. A comparative study between LRFD and allowable stress design (ASD) is also presented with a design example. (C) 2014 Elsevier Ltd. All rights reserved.

The Presence of Multiple Cellular Defects Associated with a Novel G50E Iron-Sulfur Cluster Scaffold Protein ( ISCU) Mutation Leads to Development of Mitochondrial Myopathy

Background: Muscle-specific deficiency of iron-sulfur (Fe-S) cluster scaffold protein (ISCU) leads to myopathy. Results: Cells carrying the myopathy-associated G50E ISCU mutation demonstrate impaired Fe-S cluster biogenesis and mitochondrial dysfunction. Conclusion: Reduced mitochondrial respiration as a result of diminished Fe-S cluster synthesis results in muscle weakness in myopathy patients. Significance: The molecular mechanism behind disease progression should provide invaluable information to combat ISCU myopathy. Iron-sulfur (Fe-S) clusters are versatile cofactors involved in regulating multiple physiological activities, including energy generation through cellular respiration. Initially, the Fe-S clusters are assembled on a conserved scaffold protein, iron-sulfur cluster scaffold protein (ISCU), in coordination with iron and sulfur donor proteins in human mitochondria. Loss of ISCU function leads to myopathy, characterized by muscle wasting and cardiac hypertrophy. In addition to the homozygous ISCU mutation (g.7044GC), compound heterozygous patients with severe myopathy have been identified to carry the c.149GA missense mutation converting the glycine 50 residue to glutamate. However, the physiological defects and molecular mechanism associated with G50E mutation have not been elucidated. In this report, we uncover mechanistic insights concerning how the G50E ISCU mutation in humans leads to the development of severe ISCU myopathy, using a human cell line and yeast as the model systems. The biochemical results highlight that the G50E mutation results in compromised interaction with the sulfur donor NFS1 and the J-protein HSCB, thus impairing the rate of Fe-S cluster synthesis. As a result, electron transport chain complexes show significant reduction in their redox properties, leading to loss of cellular respiration. Furthermore, the G50E mutant mitochondria display enhancement in iron level and reactive oxygen species, thereby causing oxidative stress leading to impairment in the mitochondrial functions. Thus, our findings provide compelling evidence that the respiration defect due to impaired biogenesis of Fe-S clusters in myopathy patients leads to manifestation of complex clinical symptoms.

Whole exome sequencing identifies a novel splice-site mutation in ADAMTS17 in an Indian family with Weill-Marchesani syndrome

Purpose: Weill-Marchesani syndrome (WMS) is a rare connective tissue disorder, characterized by short stature, micro-spherophakic lens, and stubby hands and feet (brachydactyly). WMS is caused by mutations in the FBN1, ADAMTS10, and LTBP2 genes. Mutations in the LTBP2 and ADAMTS17 genes cause a WMS-like syndrome, in which the affected individuals show major features of WMS but do not display brachydactyly and joint stiffness. The main purpose of our study was to determine the genetic cause of WMS in an Indian family. Methods: Whole exome sequencing (WES) was used to identify the genetic cause of WMS in the family. The cosegregation of the mutation was determined with Sanger sequencing. Reverse transcription (RT)-PCR analysis was used to assess the effect of a splice-site mutation on splicing of the ADAMTS17 transcript. Results: The WES analysis identified a homozygous novel splice-site mutation c.873+1G>T in a known WMS-like syndrome gene, ADAMTS17, in the family. RT-PCR analysis in the patient showed that exon 5 was skipped, which resulted in the deletion of 28 amino acids in the ADAMTS17 protein. Conclusions: The mutation in the WMS-like syndrome gene ADAMTS17 also causes WMS in an Indian family. The present study will be helpful in genetic diagnosis of this family and increases the number of mutations of this gene to six.

Shaking table tests to investigate the influence of various factors on the liquefaction resistance of sands

This paper presents the shaking table studies to investigate the factors that influence the liquefaction resistance of sand. A uniaxial shaking table with a perspex model container was used for the model tests, and saturated sand beds were prepared using wet pluviation method. The models were subjected to horizontal base shaking, and the variation of pore water pressure was measured. Three series of tests varying the acceleration and frequency of base shaking and density of the soil were carried out on sand beds simulating free field condition. Liquefaction was visualized in some model tests, which was also established through pore water pressure ratios. Effective stress was calculated at the point of pore water pressure measurement, and the number of cycles required to liquefy the sand bed were estimated and matched with visual observations. It was observed that there was a gradual variation in pore water pressure with change in base acceleration at a given frequency of shaking. The variation in pore water pressure is not significant for the range of frequency used in the tests. The frequency of base shaking at which the sand starts to liquefy when the sand bed is subjected to any specific base acceleration depends on the density of sand, and it was observed that the sand does not liquefy at any other frequency less than this. A substantial improvement in liquefaction resistance of the sand was observed with the increase in soil density, inferring that soil densification is a simple technique that can be applied to increase the liquefaction resistance.

A Novel Mutation in the Transglutaminase-1 Gene in an Autosomal Recessive Congenital Ichthyosis Patient

Structure-function implication on a novel homozygous Trp250/Gly mutation of transglutaminase-1 (TGM1) observed in a patient of autosomal recessive congenital ichthyosis is invoked from a bioinformatics analysis. Structural consequences of this mutation are hypothesized in comparison to homologous enzyme human factor XIIIA accepted as valid in similar structural analysis and are projected as guidelines for future studies at an experimental level on TGM1 thus mutated.

Enhancement of Corrosion Resistance of Zinc Coatings Using Green Additives

In the present work, morphology, microstructure, and electrochemical behavior of Zn coatings containing non-toxic additives have been investigated. Zn coatings were electrodeposited over mild steel substrates using Zn sulphate baths containing four different organic additives: sodium gluconate, dextrose, dextrin, and saccharin. All these additives are ``green'' and can be derived from food contents. Morphological and structural characterization using electron microscopy, x-ray diffraction, and texture co-efficient analysis revealed an appreciable alteration in the morphology and texture of the deposit depending on the type of additive used in the Zn plating bath. All the Zn coatings, however, were nano-crystalline irrespective of the type of additive used. Polarization and electrochemical impedance spectroscopic analysis, used to investigate the effect of the change in microstructure and morphology on corrosion resistance behavior, illustrated an improved corrosion resistance for Zn deposits obtained from plating bath containing additives as compared to the pure Zn coatings.

The ballistic resistance of thin aluminium plates with varying degrees of fixity along the circumference

The ballistic performance of thin aluminium targets and influence thereon of different circumferential fixity conditions were studied both experimentally and by finite element simulations. A pressure gun was employed to carry out the experiments while the numerical simulations were performed on ABAQUS/Explicit finite element code using Johnson-Cook elasto-viscoplastic material model. 1 mm thick 1100-H12 aluminium plates of free span diameter 255 mm were normally impacted by 19 mm diameter ogive and blunt nosed projectiles. The boundary conditions of the plate were varied by varying the region of fixity along its circumference as 100%, 75%, 50% and 25% in experiments and the numerical simulations. Further, simulations were carried out to compare the response of the plates with 50% and 75% continuous fixity with those with two and three symmetrical intermittent regions of 25% fixity respectively. The variation in the boundary condition has been found to have insignificant influence on the failure mode of the target however; it significantly affected the mechanics of target deformation and its energy absorption capacity. The ballistic limit increased with decrease in the region of fixity. It decreased for intermittent fixity in comparison with equivalent continuous fixity. And, it has been found to be higher for the impact with projectile having blunt nose in comparison with the one having ogive nose. (C) 2014 Elsevier Ltd. All rights reserved.

Probing a spin-glass state in SrRuO3 thin films through higher-order statistics of resistance fluctuations

The complex perovskite oxide SrRuO3 shows intriguing transport properties at low temperatures due to the interplay of spin, charge, and orbital degrees of freedom. One of the open questions in this system is regarding the origin and nature of the low-temperature glassy state. In this paper we report on measurements of higher-order statistics of resistance fluctuations performed in epitaxial thin films of SrRuO3 to probe this issue. We observe large low-frequency non-Gaussian resistance fluctuations over a certain temperature range. Our observations are compatible with that of a spin-glass system with properties described by hierarchical dynamics rather than with that of a simple ferromagnet with a large coercivity.

Uplift Resistance of Long Pipelines in the Presence of Seismic Forces

The vertical uplift resistance of long pipes buried in sands and subjected to pseudostatic seismic forces has been computed by using the lower-bound theorem of the limit analysis in conjunction with finite elements and nonlinear optimization. The soil mass is assumed to follow the Mohr-Coulomb failure criterion and an associated flow rule. The failure load is expressed in the form of a nondimensional uplift factor F-gamma. The variation of F-gamma is plotted as a function of the embedment ratio of the pipe, horizontal seismic acceleration coefficient (k(h)), and soil friction angle (phi). The magnitude of F-gamma is found to decrease continuously with an increase in the horizontal seismic acceleration coefficient. The reduction in the uplift resistance becomes quite significant, especially for greater values of embedment ratios and lower values of friction angle. The predicted uplift resistance was found to compare well with the existing results reported from the literature. (C) 2014 American Society of Civil Engineers.

Effect of Groundwater Seepage on Uplift Resistance of Buried Pipelines

The uplift resistance of pipelines buried in sands, in the presence of inclined groundwater flow, considering both upward and downward flow directions, has been determined by using the lower bound finite elements limit analysis in conjunction with nonlinear optimization. A correction factor (f (gamma) ), which needs to be multiplied with the uplift factor (F (gamma) ), has been computed to account for groundwater seepage. The variation of f (gamma) has been obtained as a function of i(gamma (w) /gamma (sub) ) for different horizontal inclinations (theta) of groundwater flow; where i = absolute magnitude of hydraulic gradient along the direction of flow, gamma (w) is the unit weight of water and gamma (sub) is the submerged unit weight of soil mass. For a given magnitude of i, there exists a certain critical value of theta for which the magnitude of f (gamma) becomes the minimum. An example has also been presented to illustrate the application of the results obtained for designing pipelines in presence of groundwater seepage.

Microstructure-hardness-fretting wear resistance correlation in ultrafine grained Cu-TiB2-Pb composites

The retention of the desired combination of mechanical/tribological properties in ultrafine grained materials presents important challenges in the field of bulk metallic composites. In order to address this aspect, the present work demonstrates how one can achieve a good combination of hardness and wear resistance in Cu-Pb-TiB2 composites, consolidated by spark plasma sintering at low temperatures ( < 500 degrees C). Transmission electron microscope (TEM) studies reveal ultrafine grains of Cu (100-400 nm) with coarser TiB2 particles (1-2 mu m) along with fine scale Pb dispersoid at triple junctions or at the grain boundaries of Cu. Importantly, a high hardness of around 2.2 GPa and relative density of close to 90% relative density (rho(theo)) have been achieved for Cu-15 wt% TiB2-10 wt% Pb composite. Such property theo, combination has never been reported for any Cu-based nanocomposite, by conventional processing route. In reference to the tribological performance, fretting wear tests were conducted on the sintered nanocomposites and a good combination of steady state COF (0.6-0.7) and wear rate (10-4 mm(3)/N m) were measured. An inverse relationship between wear rate and hardness was recorded and this commensurates well with Archard's relationship of abrasive wear. The formation of a wear-resistant delaminated tribolayer consisting of TiB2 particles and ultrafine oxide debris, (Cu, Fe, Ti)(x)O-y as confirmed from subsurface imaging using focused ion beam microscopy has been identified as the key factors for the low wear rate of these composites. (C) 2014 Elsevier B.V. All rights reserved.

Genome-wide methylation profiling identifies an essential role of reactive oxygen species in pediatric glioblastoma multiforme and validates a methylome specific for H3 histone family 3A with absence of G-CIMP/isocitrate dehydrogenase 1 mutation

Background. Pediatric glioblastoma multiforme (GBM) is rare, and there is a single study, a seminal discovery showing association of histone H3.3 and isocitrate dehydrogenase (IDH) 1 mutation with a DNA methylation signature. The present study aims to validate these findings in an independent cohort of pediatric GBM, compare it with adult GBM, and evaluate the involvement of important functionally altered pathways. Methods. Genome-wide methylation profiling of 21 pediatric GBM cases was done and compared with adult GBM data (GSE22867). We performed gene mutation analysis of IDH1 and H3 histone family 3A (H3F3A), status evaluation of glioma cytosine-phosphate-guanine island methylator phenotype (G-CIMP), and Gene Ontology analysis. Experimental evaluation of reactive oxygen species (ROS) association was also done. Results. Distinct differences were noted between methylomes of pediatric and adult GBM. Pediatric GBM was characterized by 94 hypermethylated and 1206 hypomethylated cytosine-phosphate-guanine (CpG) islands, with 3 distinct clusters, having a trend to prognostic correlation. Interestingly, none of the pediatric GBM cases showed G-CIMP/IDH1 mutation. Gene Ontology analysis identified ROS association in pediatric GBM, which was experimentally validated. H3F3A mutants (36.4%; all K27M) harbored distinct methylomes and showed enrichment of processes related to neuronal development, differentiation, and cell-fate commitment. Conclusions. Our study confirms that pediatric GBM has a distinct methylome compared with that of adults. Presence of distinct clusters and an H3F3A mutation-specific methylome indicate existence of epigenetic subgroups within pediatric GBM. Absence of IDH1/G-CIMP status further indicates that findings in adult GBM cannot be simply extrapolated to pediatric GBM and that there is a strong need for identification of separate prognostic markers. A possible role of ROS in pediatric GBM pathogenesis is demonstrated for the first time and needs further evaluation.