A unified viscoplastic model for high temperature low cycle fatigue of service-aged P91 steel

The finite element (FE) implementation of a hyperbolic sine unified cyclic viscoplasticity model is presented. The hyperbolic sine flow rule facilitates the identification of strain-rate independent material parameters for high temperature applications. This is important for the thermo-mechanical fatigue of power plants where a significant stress range is experienced during operational cycles and at stress concentration features, such as welds and branched connections. The material model is successfully applied to the characterisation of the high temperature low cycle fatigue behavior of a service-aged P91 material, including isotropic (cyclic) softening and nonlinear kinematic hardening effects, across a range of temperatures and strain-rates

MRI diffusion-based filtering: a note on performance characterisation

Frequently MRI data is characterised by a relatively low signal to noise ratio (SNR) or contrast to noise ratio (CNR). When developing automated Computer Assisted Diagnostic (CAD) techniques the errors introduced by the image noise are not acceptable. Thus, to limit these errors, a solution is to filter the data in order to increase the SNR. More importantly, the image filtering technique should be able to reduce the level of noise, but not at the expense of feature preservation. In this paper we detail the implementation of a number of 3D diffusion-based filtering techniques and we analyse their performance when they are applied to a large collection of MR datasets of varying type and quality

Alignment of the N-terminal part of vertebrate-derived AWAT2 and DGAT2 sequences.

<p>Vertebrate-derived sequences were obtained from the UniProt database [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145797#pone.0145797.ref037" target="_blank">37</a>] and aligned using the Clustal Omega tool [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145797#pone.0145797.ref038" target="_blank">38</a>]. The membrane topology was analyzed by using the SOSUI tool [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145797#pone.0145797.ref017" target="_blank">17</a>]. Predicted TM domains are highlighted in gray, whereas parts of the sequence corresponding to the putative neutral lipid binding domain “FLXLXXX” in mouse DGAT2 are highlighted in black. The conserved motifs pGGRR and YFP are underlined. Mouse DGAT2 and AWAT2, which were used in this study, are printed in bold. In case of mouse DGAT2, the indicated TM structure represents the actual topology determined by Stone et al. 2006 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145797#pone.0145797.ref019" target="_blank">19</a>]. Besides an abbreviation for each enzyme, also the respective UniProt-identifier is listed. A set of 10 conserved amino acid positions were identified, that were different between DGAT2 and AWAT2 sequences. 9 of these positions are in the shown region and marked by arrow heads.</p

Separation of neutral lipids derived from yeast cultures expressing different mouse AWAT2 variants, an empty vector control, AWAT2 wt or DGAT2 wt.

<p>pYES2/NT empty vector control (left side), mouse AWAT2 and DGAT2 wild type enzymes (middle) as well as domain swap variants derived from those two enzymes (right) were expressed in <i>S</i>. <i>cerevisiae</i> H1246 and the cultures were supplemented with 18:1-OH. The left part of the figure, which shows the empty vector control, originates from a different TLC plate than the rest of the shown samples do. Similar results were obtained when cultures were supplemented with 16:0-OH (not shown). VLC fatty acyl-containing WEs are indicated by arrows. COOH = free fatty acids, OH = fatty alcohols, TAG = triacylglycerols, WE = wax esters, VLC WE = very long chain fatty acyl-containing wax esters, SE = sterol esters. Data are representative for at least three independent biological replicates.</p

Separation of neutral lipids derived from yeast cultures expressing different mouse AWAT2 variants.

<p>All variants were expressed in <i>S</i>. <i>cerevisiae</i> H1246 and supplemented with 18:1-OH. Similar results were obtained when cultures were supplemented with 16:0-OH (not shown). VLC fatty acyl-containing WEs are indicated by arrows. COOH = free fatty acids, OH = fatty alcohols, TAG = triacylglycerols, WE = wax esters, VLC WE = very long chain fatty acyl-containing wax esters, SE = sterol esters. Data are representative for at least three independent biological replicates.</p

Mass spectra of VLC fatty acyl-harboring WEs produced by mouse cultures expressing V2 fed with 16:0-OH.

<p>A. GC analysis of WEs derived from a culture expressing V2 (same chromatogram as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145797#pone.0145797.g004" target="_blank">Fig 4B</a> left hand side). B. Mass spectrum of peak (B) identified it as hexadecanoyl-eicosanoate (16:0–20:0), C. mass spectrum of peak (C) identified it as hexadecanoyl-docosanoate (16:0–22:0), mass spectrum of peak (D) identified it as hexadecanoyl-tetracosanoate (16:0–24:0) and mass spectrum of peak (E) identified it as hexadecanoyl-hexacosanoate (16:0–26:0). The results shown here for cultures expressing V2 are also representative for cultures expressing V5, mouse AWAT2 N36R as well as AWAT2 A25F N36R (not shown).</p

Comparison of WEs derived from yeast cultures expressing AWAT2 or V2.

<p>A. GC analysis of WEs derived from a culture expressing mouse AWAT2 either fed with 16:0-OH (left chromatogram) or 18:1-OH (right chromatogram). B. GC analysis of WEs derived from a culture expressing V2 either fed with 16:0-OH (left chromatogram) or 18:1-OH (right chromatogram). In comparison to AWAT2, V2 expressing cultures synthesize four additional WE upon feeding 16:0-OH (left chromatogram) and a single additional WE upon feeding 18:1-OH (right chromatogram). The results shown here for cultures expressing V2 are also representative for cultures expressing V5, mouse AWAT2 N36R as well as AWAT2 A25F N36R (not shown). Data are representative for at least three independent biological replicates.</p

A. Topological model of AWAT2 in accordance to data generated by the services of Phobius [18], TMHMM [16] and SOSUI [17]. According to the model, AWAT2 is predicted to contain an N-terminal cytoplasmic tail that is linked to two TM domains, which are connected by a short linker. The remaining C-terminal sequence forms again a cytosolic domain, which contains the catalytic HPHG motif of the enzyme. A hydrophobic patch that may form a membrane contact is located in the middle of this domain. B. Predicted domain structures of mouse AWAT2 and mouse DGAT2. The conserved TM domains (dark grey/white boxes), the hydrophobic patch (hatched boxes), the active site motif HPHG and the putative neutral lipid binding motif “FLXLXXX” of DGAT2 are indicated. C. Domain swap variants of mouse AWAT2 and mouse DGAT2.

<p>Again, the conserved TM domains (dark grey/white boxes) and the hydrophobic patch (hatched boxes) are indicated. The sequences of mouse AWAT2 and mouse DGAT2 were used to construct seven domain swap variants (V1-V7), in which different parts of mouse AWAT2 were exchanged for the respective parts of mouse DGAT2. Mouse DGAT2 derived parts are shown in black (non-TM domains) and in white (TM-domains), respectively.</p

Comparison of WS and DGAT enzyme reaction.

<p>Wax synthases (WSs) or acyl-CoA:wax alcohol acyltransferases catalyze the condensation of a fatty alcohol with an acyl-CoA, thereby forming wax esters (WEs). In contrast, acyl-CoA:diacylglycerol O-acyltransferases (DGATs) catalyze the condensation of an acyl-CoA molecule with diacylglycerol (DAG) to yield triacylglycerols (TAGs).</p

MOESM10 of High-level accumulation of oleyl oleate in plant seed oil by abundant supply of oleic acid substrates to efficient wax ester synthesis enzymes

Additional file 10: Table S6. List of DNA constructs used in this study for expressing wax ester synthesis enzymes