Optimising postbuckling composite panels for damage resistance

The design of current composite primary aerostructures, such as fuselage or wing stiffened panels, tends to be conservative due to the susceptibility of the relatively weak skin-stiffener interface. This weakness is due to through-thickness stresses which are exacerbated by deformations due to buckling. This paper presents a finite-elementbased optimization strategy, utilizing a global-local modelling approach, for postbuckling stiffened panels which takes into account damage mechanisms which may lead to delamination and subsequent failure of the panel due to stiffener debonding. A genetic algorithm was linked to a finite element package to automate the iterative procedure and maximize the damage resistance of the panel in postbuckling. For a given loading condition, the procedure optimized the panel’s skin layup leading to a design displaying superior damage resistance compared to non-optimized designs

‘The Violence of History: Rosa Chacel’s Memorias de Leticia Valle’

Leticia Valle, the eleven-year-old narrator and protagonist of Rosa Chacel’s 1945 novel Memorias de Leticia Valle seduces and destroys her history teacher, Daniel. Here, I argue that Daniel represents traditionalist, right-wing interpretations of Spanish history while also recalling the importance of the colonial wars in Morocco in the build up to the Civil War, and the Nationalists’ use of Moroccan conscripts and recruits within the peninsula. Written at a time when history was being used to justify an armed rebellion, a civil war, and the imposition of a brutal dictatorship, Chacel’s novel depends on ellipses and absence to question historiographical principles. Furthermore, it combines continued reference to Spanish history with the use of violent and militant language. The most devastating conflict of all is between Leticia and Daniel: she silences and dehumanizes him, though she is not able to fully explain what happened. Writing from Switzerland, Chacel’s narrator takes possession of Spanish history at a time when dissent within Spain was being silenced by the Francoist regime.

HDAC1 and HDAC2 independently predict mortality in hepatocellular carcinoma by a competing risk regression model in a Southeast Asian population

Histone deacetylases (HDACs) are enzymes involved in transcriptional repression. We aimed to examine the significance of HDAC1 and HDAC2 gene expression in the prediction of recurrence and survival in 156 patients with hepatocellular carcinoma (HCC) among a South East Asian population who underwent curative surgical resection in Singapore. We found that HDAC1 and HDAC2 were upregulated in the majority of HCC tissues. The presence of HDAC1 in tumor tissues was correlated with poor tumor differentiation. Notably, HDAC1 expression in adjacent non-tumor hepatic tissues was correlated with the presence of satellite nodules and multiple lesions, suggesting that HDAC1 upregulation within the field of HCC may contribute to tumor spread. Using competing risk regression analysis, we found that increased cancer-specific mortality was significantly associated with HDAC2 expression. Mortality was also increased with high HDAC1 expression. In the liver cancer cell lines, HEP3B, HEPG2, PLC5, and a colorectal cancer cell line, HCT116, the combined knockdown of HDAC1 and HDAC2 increased cell death and reduced cell proliferation as well as colony formation. In contrast, knockdown of either HDAC1 or HDAC2 alone had minimal effects on cell death and proliferation. Taken together, our study suggests that both HDAC1 and HDAC2 exert pro-survival effects in HCC cells, and the combination of isoform-specific HDAC inhibitors against both HDACs may be effective in targeting HCC to reduce mortality.

Vitamin D3 suppresses morphological evolution of the cribriform cancerous phenotype

Development of cribriform morphology (CM) heralds malignant change in human colon but lack of mechanistic understanding hampers preventive therapy. This study investigated CM pathobiology in three-dimensional (3D) Caco-2 culture models of colorectal glandular architecture, assessed translational relevance and tested effects of 1,25(OH)2D3, the active form of vitamin D. CM evolution was driven by oncogenic perturbation of the apical polarity (AP) complex comprising PTEN, CDC42 and PRKCZ (phosphatase and tensin homolog, cell division cycle 42 and protein kinase C zeta). Suppression of AP genes initiated a spatiotemporal cascade of mitotic spindle misorientation, apical membrane misalignment and aberrant epithelial configuration. Collectively, these events promoted “Swiss cheese-like” cribriform morphology (CM) comprising multiple abnormal “back to back” lumens surrounded by atypical stratified epithelium, in 3D colorectal gland models. Intestinal cancer driven purely by PTEN-deficiency in transgenic mice developed CM and in human CRC, CM associated with PTEN and PRKCZ readouts. Treatment of PTEN-deficient 3D cultures with 1,25(OH)2D3 upregulated PTEN, rapidly activated CDC42 and PRKCZ, corrected mitotic spindle alignment and suppressed CM development. Conversely, mutationally-activated KRAS blocked 1,25(OH)2D3 rescue of glandular architecture. We conclude that 1,25(OH)2D3 upregulates AP signalling to reverse CM in a KRAS wild type (wt), clinically predictive CRC model system. Vitamin D could be developed as therapy to suppress inception or progression of a subset of colorectal tumors.

Validating the use of intrinsic markers in body feathers to identify inter‑individual differences in non‑breeding areas of northern fulmars

Many wildlife studies use chemical analyses to explore spatio-temporal variation in diet, migratory patterns and contaminant exposure. Intrinsic markers are particularly valuable for studying non-breeding marine predators, when direct methods of investigation are rarely feasible. However, any inferences regarding foraging ecology are dependent upon the time scale over which tissues such as feathers are formed. In this study, we validate the use of body feathers for studying non-breeding foraging patterns in a pelagic seabird, the northern fulmar. Analysis of carcasses of successfully breeding adult fulmars indicated that body feathers moulted between September and March, whereas analyses of carcasses and activity patterns suggested that wing feather and tail feather moult occurred during more restricted periods (September to October and September to January, respectively). By randomly sampling relevant body feathers, average values for individual birds were shown to be consistent. We also integrated chemical analyses of body feather with geolocation tracking data to demonstrate that analyses of δ13C and δ15N values successfully assigned 88 % of birds to one of two broad wintering regions used by breeding adult fulmars from a Scottish study colony. These data provide strong support for the use of body feathers as a tool for exploring non-breeding foraging patterns and diet in wide-ranging, pelagic seabirds.

Hα Line Profile Asymmetries and the Chromospheric Flare Velocity Field

The asymmetries observed in the line profiles of solar flares can provide important diagnostics of the properties and dynamics of the flaring atmosphere. In this paper the evolution of the Hα and Ca ii λ8542 lines are studied using high spatial, temporal, and spectral resolution ground-based observations of an M1.1 flare obtained with the Swedish 1 m Solar Telescope. The temporal evolution of the Hα line profiles from the flare kernel shows excess emission in the red wing (red asymmetry) before flare maximum and excess in the blue wing (blue asymmetry) after maximum. However, the Ca ii λ8542 line does not follow the same pattern, showing only a weak red asymmetry during the flare. RADYN simulations are used to synthesize spectral line profiles for the flaring atmosphere, and good agreement is found with the observations. We show that the red asymmetry observed in Hα is not necessarily associated with plasma downflows, and the blue asymmetry may not be related to plasma upflows. Indeed, we conclude that the steep velocity gradients in the flaring chromosphere modify the wavelength of the central reversal in the Hα line profile. The shift in the wavelength of maximum opacity to shorter and longer wavelengths generates the red and blue asymmetries, respectively.

Early Implementation of BIM into a Cold-Formed Steel Design/ Fabricator and an Architectural/Planning Consultancy

There is a broad consensus surrounding the ability of building information modelling (BIM) to positively impact a project by enabling greater collaboration. This paper aims to examine the development of BIM and how it can contribute to the evermore present and growing cold-formed steel (CFS) industry. This is achieved thorough a comprehensive literature review and four exploratory interviews with industry experts. Work has been carried out, for the first time, alongside one of the UK’s largest CFS Designer/Fabricators in conjunction with Northern Ireland’s leading Architectural and Town Planning Consultants in the identification and dissemination of information. The capabilities of BIM have been investigated through modeling of simple CFS structures n consultation with the project partners. By scrutinising the literature and associated interviews, the primary opportunities, as well as barriers, of BIM implementation have been investigated in the context of these companies. It is essential to develop greater understanding of the flexibility, adaptability and interoperability of BIM software as the UK construction industry faces a daunting challenge; fully collaborative 3D BIM as required by the UK Government under the “Government Construction Strategy” by 2016 in all public sector projects. This paper, and the wider study that it stems from, approaches the problem from a new angle, from sections of the construction industry that have not yet fully embedded BIM.