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Abstract: We present an overview of our recent work in tuning and controlling the structural, magnetic and electronic dimensionality of 2D van-der-Waals antiferromagnetic compounds (Transition-Metal)PS3. Low-dimensional magnetic systems such as these provide rich opportunities for studying new physics and the evolution of established behaviours with changing dimensionality. These materials can be exfoliated to monolayer thickness and easily stacked and combined into functional heterostructures. Alternatively, the application of hydrostatic pressure can be used to controllably close the van-der-Waals interplanar gap and tune the crystal structure and electron exchange paths towards a 3D nature. We collect and discuss trends and contrasts in our data from electrical transport, Raman scattering and synchrotron x-ray measurements, as well as insight from theoretical calculations and other results from the literature. We discuss structural transitions with pressure common to all materials measured, and link these to Mott insulator-transitions in these compounds at high pressures. Key new results include magnetotransport and resistivity data in the high-pressure metallic states, which show potentially interesting qualities for a new direction of future work focused on low temperature transport and quantum critical physics.

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Abstract: Ultrathin epitaxial films of ferromagnetic insulators (FMIs) with Curie temperatures near room temperature are critically needed for use in dissipationless quantum computation and spintronic devices. However, such materials are extremely rare. Here, a room‐temperature FMI is achieved in ultrathin La0.9Ba0.1MnO3 films grown on SrTiO3 substrates via an interface proximity effect. Detailed scanning transmission electron microscopy images clearly demonstrate that MnO6 octahedral rotations in La0.9Ba0.1MnO3 close to the interface are strongly suppressed. As determined from in situ X‐ray photoemission spectroscopy, O K‐edge X‐ray absorption spectroscopy, and density functional theory, the realization of the FMI state arises from a reduction of Mn eg bandwidth caused by the quenched MnO6 octahedral rotations. The emerging FMI state in La0.9Ba0.1MnO3 together with necessary coherent interface achieved with the perovskite substrate gives very high potential for future high performance electronic devices.

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Abstract: Plasmodium falciparum is the most lethal of human-infective malaria parasites. A hallmark of P. falciparum malaria is extensive remodeling of host erythrocytes by the parasite, which facilitates the development of virulence properties such as host cell adhesion to the endothelial lining of the microvasculature. Host remodeling is mediated by a large complement of parasite proteins exported to the erythrocyte; among them is a single heat shock protein (Hsp)70–class protein chaperone, P. falciparum Hsp70-x (PfHsp70-x). PfHsp70-x was previously shown to assist the development of virulent cytoadherence characteristics. Here, we show that PfHsp70-x also supports parasite growth under elevated temperature conditions that simulate febrile episodes, especially at the beginning of the parasite life cycle when most of host cell remodeling takes place. Biochemical and biophysical analyses of PfHsp70-x, including crystallographic structures of its catalytic domain and the J-domain of its stimulatory Hsp40 cochaperone, suggest that PfHsp70-x is highly similar to human Hsp70 chaperones endogenous to the erythrocyte. Nevertheless, our results indicate that selective inhibition of PfHsp70-x function using small molecules may be possible and highlight specific sites of its catalytic domain as potentially of high interest. We discuss the likely roles of PfHsp70-x and human chaperones in P. falciparum biology and how specific inhibitors may assist us in disentangling their relative contributions.

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Abstract: The hydrophobic central cavity of a water‐soluble M8L12 cubic coordination cage can accommodate a range of phospho‐diester and phospho‐triester guests such as the insecticide 'dichlorvos' (2,2‐dichlorovinyl dimethyl phosphate) and the chemical warfare agent analogue diisopropyl chlorophosphate. The accumulation of hydroxide ions around the cationic cage surface due to ion‐pairing in solution generates a high local pH around the cage, resulting in catalysed hydrolysis of the phospho‐triester guests. A series of control experiments unexpectedly demonstrates that – in marked contrast to previous cases – it is not necessary for the phospho‐triester substrates to be bound inside the cavity for catalysed hydrolysis to occur. This suggests that catalysis can occur on the exterior surface of the cage as well as the interior surface, with the exterior‐binding catalysis pathway dominating here because of the small binding constants for these phospho‐triester substrates in the cage cavity. These observations suggest that cationic but hydrophobic surfaces could act as quite general catalysts in water by bringing substrates into contact with the surface (via the hydrophobic effect) where there is also a high local concentration of anions (due to ion‐pairing / electrostatic effects).

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Abstract: During CO2 storage in depleted oil fields, under immiscible conditions, CO2 can be trapped in the pore space by capillary forces, providing safe storage over geological times - a phenomenon named capillary trapping. Synchrotron X-ray imaging was used to obtain dynamic three-dimensional images of the flow of the three phases involved in this process - brine, oil and gas (nitrogen) - at high pressure and temperature, inside the pore space of Ketton limestone. First, using continuous imaging of the porous medium during gas injection, performed after waterflooding, we observed chains of multiple displacements between the three phases, caused by the connectivity of the pore space. Then, brine was re-injected and double capillary trapping - gas trapping by oil and oil trapping by brine - was the dominant double displacement event. We computed pore occupancy, saturations, interfacial area, mean curvature and Euler characteristic to elucidate these double capillary trapping phenomena, which lead to a high residual gas saturation. Pore occupancy and saturation results show an enhancement of gas trapping in the presence of both oil and brine, which potentially makes CO2 storage in depleted oil reservoirs attractive, combining safe storage with enhanced oil recovery through immiscible gas injection. Mean curvature measurements were used to assess the capillary pressures between fluid pairs during double displacements and these confirmed the stability of the spreading oil layers observed, which facilitated double capillary trapping. Interfacial area and Euler characteristic increased, indicating lower oil and gas connectivity, due to the capillary trapping events.