Snow Algae of Mt. Watson

The taxonomy and life history of all the organisms that belong to the category of “snow algae” is complicated and contentious. Though scientists publish studies every year investigating these questions, many gaps remain in our collective knowledge. We conducted a study over two years to investigate a newly described genus, Sanguina, in a subglacial habitat system on Mt. Watson. Using size and morphologic data we found yearly occurrences of cysts of both species and can conjecture about their life cycle changes according to microhabitat. Additional work will be done in sequencing and reviewing data before submission for publication. Submission is a summary of current findings and a statement of research to be completed to make a scientifically publishable work

An investigation of the structure of water layers at plane and modified metal surfaces

The work presented in this thesis details the structural and chemical flexibility of water layers on a selection of plane and templated metallic surfaces. The water layers are found to adapt their structure to achieve a compromise between optimising its surface and intermolecular interactions differently in each system investigated. This compromise often results in water layers which do not stay in strict registry with the substrate, instead forming complex structures. Modifying the substrate by introducing a secondary metal affects the adsorption of water, the structure and species formed, indicating the sensitivity of water to the exact geometric and electronic structure of the substrate. Initially focussing on plane (non-templated) surfaces, we find an intact water layer on Pd(111), with a (root3 x root3)R30 LEED pattern but a disordered helium atom scattering signal. Using a combination of techniques we propose that the water layer comprises of regions of flat lying water, tightly bound atop Pd(111), separated by anti-phase domain boundaries. Water in the domain boundaries forms from H-bonded rings of water, oriented mostly H-down, interacting weakly with the surface. The disorder in the layer is likely to be in the H-down network and hampers attempts to achieve a complete picture of the detailed water structure. On Ni(110), a preliminary STM study into the structure and dissociation of water reveals that water forms a mixture of diffuse and more rigidly held hexagonal structures at low temperature. We assign the diffuse structures to chains of intact water which are labile under the influence of the tip, with the more rigidly held structures being a mixture of OH/H2O. The proportion of dissociated water increases with dose temperature, and is associated with loss of the labile structure associated with intact water by 200 K. Further study is required in order to establish if water adsorbs intact to Ni(110) at temperatures below 100 K. Creating a Pt skin alloy on a Ni(111) substrate allows us to investigate how a change in the Pt environment perturbs water adsorption. Water dissociates spontaneously on this surface, in a marked departure from its behaviour on the pure Ni or Pt surfaces. Pre-dosing the Pt/Ni(111) surface with oxygen has a negligible effect on the water desorption behaviour, confirming that the mixed OH/H2O phase is less stable on the Pt/Ni(111) surface than on Pt(111). We suggest that the reduced stability of OH(ads) groups on the Pt/Ni surface leads to the improved oxygen reduction reaction efficiency reported for this alloy, making OH less likely to act as a poison, as it is believed to on Pt(111). Based on our understanding of the optimum water adsorption site, we created a r3 Sn/Pt(111) alloy, designed to stabilise a traditional "ice-like" bilayer water structure. The water layer was investigated using HAS, LEED-IV and DFT modelling, which confirm that the water structure is indeed a simple commensurate root3 bilayer. Based on LEED-IV measurements we report the first quantitative structural study of monolayer water adsorbed at a metal surface and compare this to DFT predictions. Maintaining the (root3 x root3)R30 symmetry and altering the host metal from Pt to root3 Sn/M (M = Rh, Cu and Ni) resulted in no stable wetting structures. Alloying Sn with these metals appears to reduce the ability of Sn to accept electron density from the O of water, reducing the water-Sn interaction and leading to water forming clusters

Women’s experiences of the diagnostic journey in uterine adenomyosis:A scoping review protocol

Introduction Uterine adenomyosis is a benign gynaecological disease that causes physical and psychological problems, impacting on relationships. It is poorly understood and consequently may be diagnosed late. This protocol describes the process of conducting a systematic scoping review to retrieve and describe literature examining the daily experience and impact of living with uterine adenomyosis. It will explore the journey to diagnosis (and perceptions of what this process is like); identify the main concepts currently used in the literature and highlight gaps in knowledge for future research in relevant populations. Methods and analysis Using the Joanna Briggs Institute methodology, the population-concept-context approach is used to form clear review questions. A three-phase search strategy will locate published and unpublished evidence from multiple sources. All articles reporting on the personal experiences of women diagnosed with uterine adenomyosis will be considered. Findings from qualitative, quantitative and mixed-method study designs from all settings will be included, not limited by geography but restricted to English. Documents will be screened by the primary researcher, supported by university supervisors. Search outputs will be presented using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 flow diagram. No formal quality appraisal will be conducted. Review findings will be descriptively collated and reported consistent with the Scoping Review Extension of the PRISMA checklist. Patient and public involvement engagement reflected a positive response for the project that this protocol supports. Ethics and dissemination As primary data will not be collected, formal ethical approval is not required. Prepared as part of a professional doctorate thesis, the findings of this study will be disseminated via peer-reviewed publications, conference presentations, support groups and social media networks.</p

Strain Relief during Ice Growth on a Hexagonal Template.

Heterogeneous ice nucleation at solid surfaces impacts many areas of science, from environmental processes, such as precipitation, to microbiological systems and food processing, but the microscopic mechanisms underpinning nucleation remain unclear. Discussion of ice growth has often focused around the role of the surface in templating the structure of water, forcing the first layer to adopt the registry of the underlying substrate rather than that of ice. To grow a thick ice film, water in the first few ice layers must accommodate this strain, but understanding how this occurs requires detailed molecular-scale information that is lacking. Here we combine scanning tunneling microscopy, low-energy electron diffraction, and work-function measurements with electronic structure calculations to investigate the initial stages of ice growth on a Pt alloy surface, having a lattice spacing 6% larger than ice. Although the first layer of water forms a strictly commensurate hexagonal network, this behavior does not extend to the second layer. Instead, water forms a 2D structure containing extended defect rows made from face-sharing pentamer and octamer rings. The defect rows allow the majority of second-layer water to remain commensurate with the solid surface while compensating lateral strain by increasing the water density close to that of an ice surface. The observation of octamer-pentamer rows in ice films formed on several surfaces suggests that the octamer-pentamer defect motif acts as a flexible strain relief mechanism in thin ice films, providing a mechanism that is not available during the growth of strained films in other materials, such as semiconductors

Microencapsulated phase change materials in solar-thermal conversion systems:understanding geometry-dependent heating efficiency and system reliability

The performance of solar-thermal conversion systems can be improved by incorporation of nanocarbon-stabilized microencapsulated phase change materials (MPCMs). The geometry of MPCMs in the microcapsules plays an important role for improving their heating efficiency and reliability. Yet few efforts have been made to critically examine the formation mechanism of different geometries and their effect on MPCMs-shell interaction. Herein, through changing the cooling rate of original emulsions, we acquire MPCMs within the nanocarbon microcapsules with a hollow structure of MPCMs (h-MPCMs) or solid PCM core particles (s-MPCMs). X-ray photoelectron spectroscopy and atomic force microscopy reveals that the capsule shell of the h-MPCMs is enriched with nanocarbons and has a greater MPCMs-shell interaction compared to s-MPCMs. This results in the h-MPCMs being more stable and having greater heat diffusivity within and above the phase transition range than the s-MPCMs do. The geometry-dependent heating efficiency and system stability may have important and general implications for the fundamental understanding of microencapsulation and wider breadth of heating generating systems

Effect of Polymer Demixed Nanotopographies on Bacterial Adhesion and Biofilm Formation

As the current global threat of antimicrobial resistance (AMR) persists, developing alternatives to antibiotics that are less susceptible to resistance is becoming an urgent necessity. Recent advances in biomaterials have allowed for the development and fabrication of materials with discrete surface nanotopographies that can deter bacteria from adhering to their surface. Using binary polymer blends of polystyrene (PS), poly(methyl methacrylate) (PMMA) and polycaprolactone (PCL) and varying their relative concentrations, PS/PCL, PS/PMMA and PCL/PMMA polymer demixed thin films were developed with nanoisland, nanoribbon and nanopit topographies. In the PS/PCL system, PS segregates to the air-polymer interface, with the lower solubility PCL preferring the substrate-polymer interface. In the PS/PMMA and PCL/PMMA systems, PMMA prefers the air-polymer interface due to its greater solubility and lower surface energy. The anti-adhesion efficacy of the demixed films were tested against Pseudomonas aeruginosa (PA14). PS/PCL and PCL/PMMA demixed films showed a significant reduction in cell counts adhered on their surfaces compared to pure polymer control films, while no reduction was observed in the counts adhered on PS/PMMA demixed films. While the specific morphology did not affect the adhesion, a relationship between bacterial cell and topographical surface feature size was apparent. If the surface feature was smaller than the cell, then an anti-adhesion effect was observed; if the surface feature was larger than the cell, then the bacteria preferred to adhere. View Full-Tex