Carbide Precipitation in 2.25 Cr-1 Mo Bainitic Steel: Effect of Heating and Isothermal Tempering Conditions

The effect of the tempering heat treatment, including heating prior to the isothermal step, on carbide precipitation has been determined in a 2.25 Cr-1 Mo bainitic steel for thick-walled applications. The carbides were identified using their amount of metallic elements, morphology, nucleation sites, and diffraction patterns. The evolution of carbide phase fraction, morphology, and composition was investigated using transmission electron microscopy, X-ray diffraction, as well as thermodynamic calculations. Upon heating, retained austenite into the as-quenched material decomposes into ferrite and cementite. M₇C₃ carbides then nucleate at the interface between the cementite and the matrix, triggering the dissolution of cementite. M₂C carbides precipitate separately within the bainitic laths during slow heating. M₂₃C₆ carbides precipitate at the interfaces (lath boundaries or prior austenite grain boundaries) and grow by attracting nearby chromium atoms, which results in the dissolution of M₇C₃ and, depending on the temperature, coarsening, or dissolution of M₂C carbides, respectively.     

Hepatic ultrastructure in a neonatal piglet model of intestinal failure-associated liver disease (IFALD)

This study was designed to evaluate liver disease in neonatal piglets with surgical short bowel syndrome causing intestinal failure with partial parenteral nutrition dependence. The short bowel piglets had 75% surgical resection of distal small intestine, including all ileum and cecum, and were compared with sham controls, without resection, and to healthy sow-reared controls. After 18 days of combined parenteral and enteral nutrition in short bowel and sham piglets, liver tissue was collected for quantitative and semi-quantitative histological and ultrastructural evaluation. The short bowel piglets developed biochemical and histological cholestasis, not observed in sham and control piglets. Ultrastructural examination revealed bile canaliculus dilation with bile plugging, microvillus flattening and disappearance, but without abnormalities of the pericanalicular zone. Interestingly, these data are similar to bile canaliculus changes seen in human neonates with IFALD supporting an initial consideration of this model to elucidate the pathogenesis of IFALD.     

Study of a Classical Strobe Composition

Many strobe compositions were discovered in the past but only a few have been studied and none of them were fully understood. This article aimed at introducing the ternary composition of ammonium perchlorate as oxidizer, magnalium as fuel, and barium sulfate as metal salt. Parameters that influence its performances are analyzed. First, the binary compositions ammonium perchlorate/magnesium and ammonium perchlorate/magnalium were studied to observe the differences in behavior by using magnalium instead of magnesium. Next, variations were applied to the ternary composition changing the fuel: oxidizer:metal salt ratio. Finally the effect of potassium dichromate was analyzed. It is often added to the composition because it is known to improve the regularity and sharpness of flashes. The burning behavior was recorded using a high speed camera, together with emission spectra using a Charged‐Coupled Device (CCD) camera coupled with a spectrometer and the temporal evolution of the intensity with a photodiode coupled with an oscilloscope. The results of the experiment give first insights into the physical and chemical mechanisms and give directions to the further study on strobe reactions.     

Public–Private Partnerships for the Development of Disaster Resilient Communities

Increasingly, countries around the world are adopting policies that emphasize the importance of partnerships for disaster resilience. The overarching questions that this paper investigates are how to form and sustain (1) effective collaborative arrangements involving governments, businesses, non‐governmental organizations and communities to ensure development of disaster resilient communities, and (2) governance institutions that can effectively mobilize geographically dispersed disaster response resources with fragmented ownership. We have reviewed case studies of alternative inter‐sectoral collaborative arrangements that were formed to (1) promote the development of resilient communities and critical physical and social systems; (2) mitigate or respond to emerging crises; or (3) facilitate post‐disaster recovery and learning. We have developed grounded propositions articulating the antecedents of performance of inter‐sectoral collaborative arrangements.     

Re-engineering the construction process in the speculative house-building sector

The UK house-building industry has often been criticized for failing to meet the housing needs of the country. The traditional craft-based build process is labour intensive with a long lead-time and is difficult to control for product quality. It is also not suitable for configurable designs that would help to customize the home, and the industry has been criticized for excessive standardization of its products. Attempts at industrialization, usually employing frame or panel-based build methods seen in many countries, have failed due mainly to lack of clear objectives. A change in build technology is also only one step in addressing the concerns of poor quality and lack of product variety. The paper presents a programme of work that is being carried out with a major house builder towards re-engineering of the build process through a combination of new technology, product engineering and changes in working practices.     

Understanding and tailoring the degradation of PVA‐tyramine hydrogels

We have previously reported on a hydrogel system fabricated from poly(vinyl alcohol) (PVA) functionalized with tyramine groups (PVA‐Tyr) that has the ability to co‐polymerize with proteins in their native state. These gels were also shown to be hydrolytically degradable through the ester groups present in the functional groups. In this article, the hydrolytic degradation of the PVA‐Tyr gels is shown to be strongly dependant on pH, where at pH < 7.4 the lack of ionization of the tyramine groups resulted in slower hydrolysis. The gels' degradation was also highly influenced by temperature, where heat (>25°C) was required to facilitate the hydrolysis of the ester bonds. Moreover, the degradation rates were successfully tailored between 19 to 27 days by varying the hydrogels' initial macromer concentration. It was highlighted that the cross‐linking density was dependant on the sodium persulphate to tyramine ratio, as well as the viscosity of the macromer solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42142.     

Polysaccharides reduce in vitro IgG/IgE-binding of β-lactoglobulin after hydrolysis

We investigate the influence of charged polysaccharides such as gum arabic and low methylated pectin (LMP), and of un-charged polysaccharides such as xylan, on the in vitro digestibility of β-lactoglobulin (β-lg) and on the in vitro IgG- and IgE-binding of its digestion products. β-Ig was hydrolyzed by pepsin, and then by a trypsin/chymotrypsin mixture, in dialysis bags. SDS–PAGE electrophoresis was used to determine protein hydrolysis and immunoblotting in the presence of cow’s milk, and rabbit or human antibodies were used to assess the in vitro IgG- and IgE-binding of the digestion products. The results showed that polysaccharides influenced protein digestibility. The IgG- and IgE-bound hydrolysis products were dependent on the enzymatic hydrolysis and on the presence of polysaccharides. In all cases, IgG-binding was lower in the presence of any of the polysaccharides, and IgE-binding was non-existent or considerably reduced with LMP and xylan. In this study, LMP and xylan were the polysaccharides that most effectively reduced the immuno-reactivity of the hydrolysis products. The eventual reduction of in vivo allergenicity of milk-based food products has to be confirmed.     

POLYCYCLIC AROMATIC HYDROCARBON O-QUINONES MUTATE p53 IN HUMAN LUNG ADENOCARCINOMA (A549) CELLS

Human lung adenocarcinoma (A549) cells form reactive and redox active PAH-o-quinones via constitutively expressed aldo-keto reductases. To determine whether these metabolites mutate p53, A549 cells were treated with N-methyl-N-nitroso-N-nitroguanidine (MNNG an alkylating mutagen), anti-BPDE (diol-epoxide) and benzo[a]pyrene-7,8-dione (o-quinone). p53 cDNA was amplified from the treated cells and cotransfected with a gap-repair plasmid designed to express p53 in yeast. When mutant p53 is expressed, it fails to drive the expression of an ADE2 reporter, and the yeast strain yIG397 turns red. The following mutational frequencies were observed versus the solvent controls: 1 mM MNNG (24.2% red colonies p = .02), 1 μ M anti-BPDE (9.9% red colonies p = .02), and 10 μ M BP-7,8-dione (9.3% red colonies p = .03). MNNG gave a high frequency (49%) of the expected C > T (G > A) mutations (p = .25). While anti-BPDE and BP-7,8-dione gave A > G (T > C) transitions (p = .034 – p = .054). These mutations would result from stable N⁶-deoxyadenosine adducts, but not from oxidatively damaged bases.     

Officing: Mediating Time and the Professional Self in the Support of Nomadic Work

Today’s mobile knowledge professionals use a diversity of digital technologies to perform their work. Much of this daily technology consumption involves a variety of activities of articulation, negotiation and repair to support their work as well as their nomadic practices. This article argues that these activities mediate and structure social relations, going beyond the usual attention given to this work as a support requirement of cooperative and mobile work. Drawing on cultural approaches to technology consumption, the article introduces the concept of ‘officing’ and its three main categories of connecting, configuring and synchronizing, to show how these activities shape and are shaped by the relationship that workers have with their time and sense of professional self. This argument is made through research of professionals at a municipal council in Sydney and at a global telecommunications firm with regional headquarters in Melbourne, trialling a smartphone prototype. This research found that while officing fuels a sense of persistent time pressure and collapse of work and life boundaries, it also supports new temporal and spatial senses and opportunities for maintaining professional identities.