Antimicrobial Susceptibilities of Aerobic Isolates from Respiratory Samples of Young New Zealand Horses

3rd Annual IEEE Energy Conversion Congress and Exposition, ECCE 2011, Phoenix, AZ, 17-22 September 2011This paper presents a method of mitigating the transient overshoots of DC-DC converters operating with large load disturbances. The method involves a small auxiliary power circuit with a complementary control scheme that provides a smooth absorption and release of excess energy from and to the main DC-DC converter in the events of large load changes. This control mechanism interactively mitigates the large transient overshoots which would otherwise appear at the converter output. Since the control scheme involves an adjustable-energy-storage feature, the proposed solution is effective for any level of step-load change within a pre-specified range.Department of Electronic and Information EngineeringRefereed conference pape

Method for deriving optical telescope performance specifications for Earth-detecting coronagraphs

Direct detection and characterization of extrasolar planets has become possible with powerful new coronagraphs on ground-based telescopes. Space telescopes with active optics and coronagraphs will expand the frontier to imaging Earth-sized planets in the habitable zones of nearby Sun-like stars. Currently, NASA is studying potential space missions to detect and characterize such planets, which are dimmer than their host stars by a factor of 10¹⁰. One approach is to use a star-shade occulter. Another is to use an internal coronagraph. The advantages of a coronagraph are its greater targeting versatility and higher technology readiness, but one disadvantage is its need for an ultrastable wavefront when operated open-loop. Achieving this requires a system-engineering approach, which specifies and designs the telescope and coronagraph as an integrated system. We describe a systems engineering process for deriving a wavefront stability error budget for any potential telescope/coronagraph combination. The first step is to calculate a given coronagraph’s basic performance metrics, such as contrast. The second step is to calculate the sensitivity of that coronagraph’s performance to its telescope’s wavefront stability. The utility of the method is demonstrated by intercomparing the ability of several monolithic and segmented telescope and coronagraph combinations to detect an exo-Earth at 10 pc

Method for deriving optical telescope performance specifications for Earth-detecting coronagraphs

Direct detection and characterization of extrasolar planets has become possible with powerful new coronagraphs on ground-based telescopes. Space telescopes with active optics and coronagraphs will expand the frontier to imaging Earth-sized planets in the habitable zones of nearby Sun-like stars. Currently, NASA is studying potential space missions to detect and characterize such planets, which are dimmer than their host stars by a factor of 10¹⁰. One approach is to use a star-shade occulter. Another is to use an internal coronagraph. The advantages of a coronagraph are its greater targeting versatility and higher technology readiness, but one disadvantage is its need for an ultrastable wavefront when operated open-loop. Achieving this requires a system-engineering approach, which specifies and designs the telescope and coronagraph as an integrated system. We describe a systems engineering process for deriving a wavefront stability error budget for any potential telescope/coronagraph combination. The first step is to calculate a given coronagraph’s basic performance metrics, such as contrast. The second step is to calculate the sensitivity of that coronagraph’s performance to its telescope’s wavefront stability. The utility of the method is demonstrated by intercomparing the ability of several monolithic and segmented telescope and coronagraph combinations to detect an exo-Earth at 10 pc

Characterisation of Osteopontin in an In Vitro Model of Embryo Implantation

At the onset of pregnancy, embryo implantation is initiated by interactions between the endometrial epithelium and the outer trophectoderm cells of the blastocyst. Osteopontin (OPN) is expressed in the endometrium and is implicated in attachment and signalling roles at the embryo–epithelium interface. We have characterised OPN in the human endometrial epithelial Ishikawa cell line using three different monoclonal antibodies, revealing at least nine distinct molecular weight forms and a novel secretory pathway localisation in the apical domain induced by cell organisation into a confluent epithelial layer. Mouse blastocysts co-cultured with Ishikawa cell layers served to model embryo apposition, attachment and initial invasion at implantation. Exogenous OPN attenuated initial, weak embryo attachment to Ishikawa cells but did not affect the attainment of stable attachment. Notably, exogenous OPN inhibited embryonic invasion of the underlying cell layer, and this corresponded with altered expression of transcription factors associated with differentiation from trophectoderm (Gata2) to invasive trophoblast giant cells (Hand1). These data demonstrate the complexity of endometrial OPN forms and suggest that OPN regulates embryonic invasion at implantation by signalling to the trophectoder

Osmotic stress induces JNK-dependent embryo invasion in a model of implantation

In vitro culture during assisted reproduction technologies (ARTs) exposes pre-implantation embryos to environmental stressors, such as non-physiological nutritional, oxidative and osmotic conditions. The effects on subsequent implantation are not well understood but could contribute to poor ART efficiency and outcomes. We have used exposure to hyperosmolarity to investigate the effects of stress on the ability of embryos to interact with endometrial cells in an in vitro model. Culturing mouse blastocysts for 2 h in medium with osmolarity raised by 400 mosmol induced blastocoel collapse and re-expansion, but did not affect subsequent attachment to, or invasion of, the endometrial epithelial Ishikawa cell line. Inhibition of stress-responsive c-Jun N-terminal kinase (JNK) activity with SP600125 did not affect the intercellular interactions between these embryos and the epithelial cells. Four successive cycles of hyperosmotic stress at E5.5 had no effect on attachment, but promoted embryonic breaching of the epithelial cell layer by trophoblast giant cells in a JNK-dependent manner. These findings suggest that acute stress at the blastocyst stage may promote trophoblast breaching of the endometrial epithelium at implantation and implicates stress signalling through JNK in the process of trophectoderm differentiation into the invasive trophoblast necessary for the establishment of pregnancy. The data may lead to increased understanding of factors governing ART success rates and safety

The glycosyltransferase EOGT regulates adropin expression in decidualizing human endometrium

In pregnancy, resistance of endometrial decidual cells to stress signals is critical for the integrity of the feto-maternal interface and, by extension, survival of the conceptus. O-GlcNAcylation is an essential post-translational modification that links glucose sensing to cellular stress resistance. Unexpectedly, decidualization of primary endometrial stromal cells (EnSCs) was associated with a 60% reduction in O-GlcNAc modified proteins, reflecting downregulation of the enzyme that adds O-GlcNAc to substrates (O-GlcNAc transferase, OGT) but not the enzyme that removes the modification (O-GlcNAcase, OGA). Notably, EOGT, an endoplasmic reticulum-specific O-GlcNAc transferase that modifies a limited number of secreted and membrane proteins, was markedly induced in differentiating EnSCs. Knockdown of EOGT perturbed a network of decidual genes involved in multiple cellular functions. The most downregulated gene upon EOGT knockdown in decidualizing cells was ENHO, which encodes adropin, a metabolic hormone involved in energy homeostasis and glucose and fatty acid metabolism. Analysis of mid-luteal endometrial biopsies revealed an inverse correlation between endometrial EOGT and ENHO expression and body mass index. Taken together, our findings reveal that obesity impairs the EOGT-adropin axis in decidual cells, which in turn points towards a novel mechanistic link between metabolic disorders and adverse pregnancy outcome. [Abstract copyright: Copyright © 2017 Endocrine Society.

Integrating palliative care and heart failure: a systematic realist synthesis (PalliatHeartSynthesis)

Objectives (1) Develop a programme theory of why, for whom and in what contexts integrated palliative care (PC) and heart failure (HF) services work/do not work; (2) use the programme theory to co-produce with stakeholders, intervention strategies to inform best practice and future research. Methods A systematic review of all published articles and grey literature using a realist logic of analysis. The search strategy combined terms significant to the review questions: HF, PC and end of life. Documents were included if they were in English and provided data relevant to integration of PC and HF services. Searches were conducted in November 2021 in EMBASE, MEDLINE, PsycINFO, AMED, HMIC and CINAHL. Further relevant documents were identified via monthly alerts (up until April 2023) and the project stakeholder group (patient/carers, content experts and multidisciplinary practitioners). Results 130 documents were included (86 research, 22 literature reviews, 22 grey literature). The programme theory identified intervention strategies most likely to support integration of PC and HF services. These included protected time for evidence-based PC and HF education from undergraduate/postgraduate level and continuing professional practice; choice of educational setting (eg, online, face-to-face or hybrid); increased awareness and seeing benefits of PC for HF management; conveying the emotive and intellectual need for integrating PC and HF via credible champions; and prioritising PC and HF guidelines in practice. Conclusions The review findings outline the required steps to take to increase the likelihood that all key players have the capacity, opportunity and motivation to integrate PC into HF management. PROSPERO registration number CRD42021240185