Topological Persistence for Relating Microstructure and Capillary Fluid Trapping in Sandstones

Results from a series of two‐phase fluid flow experiments in Leopard, Berea, and Bentheimer sandstones are presented. Fluid configurations are characterized using laboratory‐based and synchrotron based 3‐D X‐ray computed tomography. All flow experiments are conducted under capillary‐dominated conditions. We conduct geometry‐topology analysis via persistent homology and compare this to standard topological and watershed‐partition‐based pore‐network statistics. Metrics identified as predictors of nonwetting fluid trapping are calculated from the different analytical methods and are compared to levels of trapping measured during drainage‐imbibition cycles in the experiments. Metrics calculated from pore networks (i.e., pore body‐throat aspect ratio and coordination number) and topological analysis (Euler characteristic) do not correlate well with trapping in these samples. In contrast, a new metric derived from the persistent homology analysis, which incorporates counts of topological features as well as their length scale and spatial distribution, correlates very well (R2 = 0.97) to trapping for all systems. This correlation encompasses a wide range of porous media and initial fluid configurations, and also applies to data sets of different imaging and image processing protocols.We gratefully acknowledge funding from the member companies of the ANU/UNSW Digicore Research Consortium, as well as the Australian Research Council. Adrian Sheppard is supported by Discovery Project DP160104995, Vanessa Robins is supported by ARC Future Fellowship FT140100604, and Anna Herring is supported by ARC Discovery Early Career Fellowship DE180100082

“Your Brain Isn’t All Backwards”: Asexual Young Women’s Narratives of Sexual Healthism

Scholarship on asexuality is a growing but underexplored area in the social sciences. In the U.S., asexual people (i.e., individuals who do not experience sexual attraction) navigate a society in which being a sexual person is regarded as a normal and even compulsory aspect of human health and subjectivity. Utilizing an asexual subsample from a broader study of queer young women, this article integrates Foucault’s theorizing around sexuality and repression with scholarship on healthism to examine how discourses of sexual healthism operate among asexual young women in the U.S. South. We argue that in rejecting theories of sexual repression and compulsory “healthy” sexuality, asexual young women both confirm and resist the moral authority and power of religious and health discourses to affirm their identities and find language and communities to make their experiences more intelligible to themselves and others. Our analysis advances emerging scholarship on sexual healthism and its discursive and material effects on marginalized groups

Reverse genetics in Candida albicans predicts ARF cycling is essential for drug resistance and virulence

Peer reviewedPublisher PD

Invasion Success of Bunias orientalis (Warty Cabbage) in Grasslands: A Mesocosm Experiment on the Role of Hydrological Stress and Disturbance

Climate change is altering precipitation patterns, with higher frequency and magnitude of extreme events. Specifically, longer and more pronounced waterlogged conditions are predicted after rain spells as well as more frequent droughts, especially in Central Europe. Such hydrological changes can severely affect species performance and alter the function of ecosystems, as well as favor plant invasions. Competition with native communities may change depending on water stress. Bunias orientalis is an invasive plant that may benefit from disturbance or precipitation changes. We conducted a 3-year mesocosm experiment in a common garden to investigate how invasion success of B. orientalis in native German grassland communities is affected by varying hydrological conditions (from very dry to waterlogged). We measured the establishment and growth of B. orientalis in varying water table depths in bare soil (simulating disturbance) vs. in the community. Establishment and biomass of B. orientalis was generally highest under non-stress conditions. The species was also highly tolerant to dry conditions, but only when growing in bare soil. However, performance of B. orientalis was generally low, whereby interspecific competition in communities greatly limited invasion success. This might be due to the low competitive ability of the species in conditions of hydrological stress and the near-natural grassland communities with an extensive mowing regime used in our experiment. Our results suggest that invasion success of B. orientalis in grasslands will not increase if precipitation patterns change toward more extreme events. However, disturbance that creates bare soil patches might favor B. orientalis under drought conditions

Using CoCu2_2Ga/SiO2_2 to identify stability-issues in ethanol-selective Co-Cu alloyed catalysts in carbon monoxide hydrogenation

Hydrogenation of CO to higher alcohols such as ethanol is an attractive pathway for industrial production while avoiding competition with food crops. However, thermocatalytic ethanol production from syngas is currently hindered by the lack of selective catalysts. The structural integrity of ternary-alloyed CoCu2Ga nanoparticles supported on silica was studied during thermo-catalytic CO hydrogenation. Catalysts of four different CoCu$_2$Ga weight-loadings were tested catalytically under differential conversion, showing their different intrinsic selectivity during CO hydrogenation towards ethanol, methanol, and hydrocarbons. CoCu$_2$Ga catalysts with 3.5 wt% and 17.8 wt% proved most and least selective towards ethanol formation, respectively. These two were studied in depth using STEM-EDX of fresh and spent samples showing different size distributions of the nanoparticles for all samples, and a change in the Co/Cu distribution of the nanoparticles from fresh to spent samples. In situ characterization using XRD, XANES, and EXAFS during CO hydrogenation supported the findings of the STEM-EDX and elucidated that the fresh more homogenous catalyst consisting of ternary CoCu$_2$Ga nanoparticles de-alloyed into Cu-rich and CoGa-rich nanoparticles. This de-alloying was possibly driven by two factors: the metastable phase of CoCu$_2$Ga decreasing its free energy by separating Cu and Co; and the strong interaction between Co and CO further driving a segregation. From a theoretical standpoint, Cu-Co intermetallics present the most selective catalyst to form ethanol over methane and methanol. The experimental findings presented here support the theory, although further efforts are needed to improve structural stability during the catalytic reaction

Metabolic enzyme expression highlights a key role for MTHFD2 and the mitochondrial folate pathway in cancer

Metabolic remodeling is now widely regarded as a hallmark of cancer, but it is not clear whether individual metabolic strategies are frequently exploited by many tumours. Here we compare messenger RNA profiles of 1,454 metabolic enzymes across 1,981 tumours spanning 19 cancer types to identify enzymes that are consistently differentially expressed. Our meta-analysis recovers established targets of some of the most widely used chemotherapeutics, including dihydrofolate reductase, thymidylate synthase and ribonucleotide reductase, while also spotlighting new enzymes, such as the mitochondrial proline biosynthetic enzyme PYCR1. The highest scoring pathway is mitochondrial one-carbon metabolism and is centred on MTHFD2. MTHFD2 RNA and protein are markedly elevated in many cancers and correlated with poor survival in breast cancer. MTHFD2 is expressed in the developing embryo, but is absent in most healthy adult tissues, even those that are proliferating. Our study highlights the importance of mitochondrial compartmentalization of one-carbon metabolism in cancer and raises important therapeutic hypotheses