Assessment of creep and rupture behavior of 2.25Cr-1Mo steel – A strain-based approach and its limitation

Increasing demand of 2.25Cr-1Mo steel, among different grades of low alloy Cr-Mo steels, in power plants and petrochemical industries is mainly because of its high creep resistance. Application of a strain based approach for a reliable assessment of creep and rupture behavior is thus of great importance. Creep data were generated under different microstructural conditions in the laboratory and collected from literature as well. The influence of thermal ageing and pre-strain on the shape of creep curves has been studied. Analysis of data revealed that irrespective of initial microstructures, thermal ageing increases the tendency to soften but not the pre-strain. Softening due to carbide coarsening thus appears to be the dominant mechanism of creep. Based on this, a strain based approach for creep life assessment was developed. A fairly accurate prediction of creep life up to 5% creep is achieved using eight materials constants extracted from the creep curves of steel having similar initial microstructure. The limitation and reliability of the approach used to assess creep behavior of service-exposed steels have been discussed

The karma of consumption: Role of materialism in the pursuit of life satisfaction

Purpose: This paper aims to examine how social comparison (SC) and belief in karma (KA) encourage materialism (MAT) and promote consumers’ life satisfaction (LS). Design/methodology/approach: Two studies were conducted with Indian middle class consumers to test the basic premises of the current research. The first one used a survey (N = 247), while the second one used an experimental design (N = 206). Findings: The survey results showed that SC and belief in KA promoted MAT amongst Indian consumers and further enhanced their LS. Findings from the experiment revealed a novel two-way interaction, in that the KA–MAT relationship was moderated by the underlying motivation for MAT. Research limitations/implications: Future research may validate and extend our findings using different samples to increase external validity. Practical implications: By explaining the interactive effects of MAT, its underlying motivation and belief in KA, managers will gain a better understanding of why consumers in an emerging market like India purchase conspicuous products. Originality/value: This is the first paper to study how the KA–MAT relationship influences LS amongst consumers in the world’s fastest-rising economy. Furthermore, no prior research has reported a boundary condition for the KA–MAT relationship studied here. The findings contribute to an extremely limited body of literature on KA and consumption

Spectrum of One-Dimensional Anharmonic Oscillators

We use a power-series expansion to calculate the eigenvalues of anharmonic oscillators bounded by two infinite walls. We show that for large finite values of the separation of the walls, the calculated eigenvalues are of the same high accuracy as the values recently obtained for the unbounded case by the inner-product quantization method. We also apply our method to the Morse potential. The eigenvalues obtained in this case are in excellent agreement with the exact values for the unbounded Morse potential.Comment: 11 pages, 5 figures, 4 tables; there are changes to match the version published in Can. J. Phy

Supramolecular structure in the membrane of Staphylococcus aureus

The fundamental processes of life are organized and based on common basic principles. Molecular organizers, often interacting with the membrane, capitalize on cellular polarity to precisely orientate essential processes. The study of organisms lacking apparent polarity or known cellular organizers (e.g., the bacterium Staphylococcus aureus) may enable the elucidation of the primal organizational drive in biology. How does a cell choose from infinite locations in its membrane? We have discovered a structure in the S. aureus membrane that organizes processes indispensable for life and can arise spontaneously from the geometric constraints of protein complexes on membranes. Building on this finding, the most basic cellular positioning system to optimize biological processes, known molecular coordinators could introduce further levels of complexity. All life demands the temporal and spatial control of essential biological functions. In bacteria, the recent discovery of coordinating elements provides a framework to begin to explain cell growth and division. Here we present the discovery of a supramolecular structure in the membrane of the coccal bacterium Staphylococcus aureus, which leads to the formation of a large-scale pattern across the entire cell body; this has been unveiled by studying the distribution of essential proteins involved in lipid metabolism (PlsY and CdsA). The organization is found to require MreD, which determines morphology in rod-shaped cells. The distribution of protein complexes can be explained as a spontaneous pattern formation arising from the competition between the energy cost of bending that they impose on the membrane, their entropy of mixing, and the geometric constraints in the system. Our results provide evidence for the existence of a self-organized and nonpercolating molecular scaffold involving MreD as an organizer for optimal cell function and growth based on the intrinsic self-assembling properties of biological molecules

Growth pattern of preterm and IUGR babies in an urban slum of Kolkata, west Bengal, India

The present study was carried out to analyze the growth pattern of pretermand IUGR infants from birth up to nine months of age. A longitudinal study was conducted in an urban slum of Chetla, Kolkata, India. Study population comprised of 36 low birth weight babies, out of which 13 were preterms and rest 23 were IUGR babies. Different anthropometric parameters like weight, length, head and chest circumference was measured and compared between two groups. During the entire follow up period, all the mean anthropometric parameters of the preterms lagged behind their IUGR counterparts; in contrast the growth potential of the preterms was more as revealed by their increased mean increments in terms of weight, length, head and chest circumference. Regular growth monitoring should be an essential component of care of both preterm and IUGR babies with more focused health care services for IUGR babies, so as to detect growth faltering at the earlies

Genomic analysis of the protein secretion systems in Clostridium acetobutylicum ATCC 824

AbstractConsistent information about protein secretion in Gram-positive bacteria is essentially restricted to the model organism Bacillus subtilis. Among genome-sequenced clostridia, Clostridium acetobutylicum has been the most extensively studied from a physiological point of view and is the organism for which the largest variety of molecular biology tools have been developed. Following in silico analyses, both secreted proteins and protein secretion systems were identified. The Tat (Twin arginine translocation; TC #2.A.64) pathway and ABC (ATP binding cassette) protein exporters (TC #3.A.1.) could not be identified, but the Sec (secretion) pathway (TC #3.A.5) appears to be used prevalently. Similarly, a flagella export apparatus (FEA; TC #3.A.6.), holins (TC #1.E.), and an ESAT-6/WXG100 (early secreted antigen target of 6 kDa/proteins with a WXG motif of ∼100 residues) secretion system were identified. Here, we report for the first time the identification of a fimbrilin protein exporter (FPE; TC #3.A.14) and a Tad (tight adherence) export apparatus in C. acetobutylicum. This investigation highlights the potential use of this saprophytic bacterium in biotechnological and biomedical applications as well as a model organism for studying protein secretion in pathogenic Gram-positive bacteria

Genome-wide high-throughput screening to investigate essential genes involved in methicillin-resistant Staphylococcus aureus Sequence Type 398 survival.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) Sequence Type 398 (ST398) is an opportunistic pathogen that is able to colonize and cause disease in several animal species including humans. To better understand the adaptation, evolution, transmission and pathogenic capacity, further investigations into the importance of the different genes harboured by LA-MRSA ST398 are required. In this study we generated a genome-wide transposon mutant library in an LA-MRSA ST398 isolate to evaluate genes important for bacterial survival in laboratory and host-specific environments. The transposon mutant library consisted of approximately 1 million mutants with around 140,000 unique insertion sites and an average number of unique inserts per gene of 44.8. We identified LA-MRSA ST398 essential genes comparable to other high-throughput S. aureus essential gene studies. As ST398 is the most common MRSA isolated from pigs, the transposon mutant library was screened in whole porcine blood. Twenty-four genes were specifically identified as important for bacterial survival in porcine blood. Mutations in 23 of these genes resulted in attenuated bacterial fitness. Seven of the 23 genes were of unknown function, whereas 16 genes were annotated with functions predominantly related to carbon metabolism, pH shock and a variety of regulations and only indirectly to virulence factors. Mutations in one gene of unknown function resulted in a hypercompetitive mutant. Further evaluation of these genes is required to determine their specific relevance in blood survival.This work was funded in part by the Danish Ministry of Food, Agriculture and Fisheries (Grant no. 3304-FVFP-09-F-002-1) and The Technical University of DenmarkThis is the final published version distributed under a Creative Commons Attribution License, which can also be found on the publisher's website at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.008901