Targeted adjustment of residual stresses in hot-formed components by means of process design based on finite element simulation

The aim of this work is to generate an advantageous compressive residual stress distribution in the surface area of hot-formed components by intelligent process control with tailored cooling. Adapted cooling is achieved by partial or temporal instationary exposure of the specimens to a water–air spray. In this way, macroscopic effects such as local plastification caused by inhomogeneous strains due to thermal and transformation-induced loads can be controlled in order to finally customise the surface-near residual stress distribution. Applications for hot-formed components often require special microstructural properties, which guarantee a certain hardness or ductility. For this reason, the scientific challenge of this work is to generate different residual stress distributions on components surfaces, while the geometric as well as microstructural properties of AISI 52100 alloy stay the same. The changes in the residual stresses should therefore not result from the mentioned changed component properties, but solely from the targeted process control. Within the scope of preliminary experimental studies, tensile residual stresses in a martensitic microstructure were determined on reference components, which had undergone a simple cooling in water (from the forming heat), or low compressive stresses in pearlitic microstructures were determined after simple cooling in atmospheric air. Numerical studies are used to design two tailored cooling strategies capable of generating compressive stresses in the same components. The developed processes with tailored cooling are experimentally realised, and their properties are compared to those of components manufactured involving simple cooling. Based on the numerical and experimental analyses, this work demonstrates that it is possible to influence and even invert the sign of the residual stresses within a component by controlling the macroscopic effects mentioned above

Restriction of GAGE protein expression to subpopulations of cancer cells is independent of genotype and may limit the use of GAGE proteins as targets for cancer immunotherapy

The GAGE cancer testis antigen gene family encodes products that can be recognized by autologous T cells, and GAGE proteins have been suggested as potential targets for cancer immunotherapy. Analysis of GAGE expression in tumours has primarily been performed at the level of gene transcription, whereas little is known about GAGE expression at the protein level. To evaluate the potential of GAGE proteins as targets for cancer-specific immunotherapy, we studied the expression of these proteins in normal and malignant cells/tissues using a novel panel of monoclonal antibodies. Immunohistochemical analysis of more than 250 cancer specimens demonstrated that GAGE proteins were frequently expressed in numerous cancer types and correlated with the expression of the cancer testis antigens MAGE-A1 and NY-ESO-1. Significant intercellular and subcellular differences in GAGE protein levels were observed, and most GAGE-positive tumours also contained cancer cells lacking GAGE expression. Studies of genetically homogenous cell lines with similar intercellular heterogeneous GAGE expression showed that GAGE expression was not associated with a specific genotype, but defined a phenotypically distinct population of cells. Surprisingly, in normal tissues we found that GAGE proteins were not restricted to testis, but were also present in a subset of oocytes of resting primordial follicles and in maturing oocytes. This is the first time that a cancer testis antigen has been reported in postfoetal oocytes. The lack of GAGE expression in a subset of cancer cells within GAGE-positive tumours has decisive implications for the development of GAGE-targeted cancer therapy

Gain of 20q11.21 in human pluripotent stem cells impairs TGF-β-dependent neuroectodermal commitment

Gain of 20q11.21 is one of the most common recurrent genomic aberrations in human pluripotent stem cells. Although it is known that overexpression of the antiapoptotic gene Bcl-xL confers a survival advantage to the abnormal cells, their differentiation capacity has not been fully investigated. RNA sequencing of mutant and control hESC lines, and a line transgenically overexpressing Bcl-xL, shows that overexpression of Bcl-xL is sufficient to cause most transcriptional changes induced by the gain of 20q11.21. Moreover, the differentially expressed genes in mutant and Bcl-xL overexpressing lines are enriched for genes involved in TGF-beta- and SMAD-mediated signaling, and neuron differentiation. Finally, we show that this altered signaling has a dramatic negative effect on neuroectodermal differentiation, while the cells maintain their ability to differentiate to mesendoderm derivatives. These findings stress the importance of thorough genetic testing of the lines before their use in research or the clinic

Exploring factors that influence the mainstreaming of gendered energy interventions in poor urban environments : a structured literature review

CITATION: Oosthuizen, L., De Kock, I. H. & Musango, J. K. 2020.. Exploring factors that influence the mainstreaming of gendered energy interventions in poor urban environments : a structured literature review. South African Journal of Industrial Engineering, 31(3):83-96, doi:10.7166/31-3-2421.The original publication is available at http://sajie.journals.ac.zaENGLISH ABSTRACT: Energy sectors are faced with the interconnected challenges of urbanisation and providing a growing population with accessible and sustainable energy that facilitates economic development, energy security, and poverty reduction. The Sustainable Development Goals address issues that include poverty, gender equality, energy, and sustainable cities, and highlight the need to improve the lives of poor communities and to address economic marginalisation. However, recent studies show that poor urban areas have a considerable number of female-lead households. Energy is a critical input for these households, resulting in women being increasingly vulnerable to unsustainable energy consumption patterns and energy insecurity. In this article, a structured literature review is conducted to investigate energy technologies that contribute to energy security among energy-poor women. The key factors to consider in the mainstreaming of a gender perspective into energy technology innovations are then identified and contextualised. How these factors can help achieve the sustainable development goals and contribute to ensuring sustainable energy sectors is also highlighted.AFRIKAANSE OPSOMMING: Energiesektore word gekonfronteer met die onderling gekoppelde uitdagings van verstedeliking en om ʼn groeiende bevolking te voorsien met toeganklike en volhoubare energie wat ekonomiese ontwikkeling, energiesekerheid en amoede-vermindering fasiliteer. Die Doelwitte vir Volhoubare Ontwikkeling behandel kwessies soos armoede, geslagsgelykheid, energie, en volhoubare stede en beklemtoon die noodsaaklikheid om die lewens van arm gemeenskappe te verbeter en ekonomiese marginalisering aan te spreek. Onlangse studies toon egter dat arm stedelike gebiede ʼn aansienlike aantal huishoudings met vroue aan die hoof het. Energie is ʼn kritieke inset vir hierdie huishoudings wat veroorsak dat vroue toenemend kwesbaar is vir onvolhoubare energie-verbruikpatrone en energie-onsekerheid. In hierdie artikel word ʼn gestruktureerde literatuuroorsig uitgevoer om energietegnologieë te ondersoek wat bydra tot energiesekerheid onder energie-arm vroue. Die sleutelfaktore om in ag te neem vir die integrasie van ʼn geslagsperspektief in energie-tegnologie-innovasies word vervolgens identifiseer en gekontekstualiseer. Hoe hierdie faktore kan help om die Doelwitte vir Volhoubare Ontwikkeling te bereik en kan bydra tot die versekering van volhoubare energiesektore, word ook uitgelig.http://sajie.journals.ac.za/pub/article/view/2421Publisher's versio