2,492 research outputs found

    A Robust Solution to the Super-Resolution Phase Problem in Scanning Transmission Electron Microscopy

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    From a set of images, each of poor resolution, recorded in a transmission microscope under many different incident angles of coherent illumination, it is possible to obtain wavelength-limited resolution even if there is a narrow aperture lying in the back-focal plane of the imaging lens. This is achieved by a deconvolution algorithm which retrieves the phase of the Fourier transform of the specimen. The method accounts for complex components in the transfer function of the lens, is not very sensitive to defocus and is remarkably resilient to noise. It may have important applications in overcoming the resolution limit in the scanning transmission electron microscope (STEM), where such data are readily available

    Optimized organometal halide perovskite solar cell fabrication through control of nanoparticle crystal patterning

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    The addition of Hydrogen Iodide to organometal halide perovskite precursor solution at 1% by volume leads to a significant enhancement in power conversion efficiency (PCE) in inverted solar cell devices, increasing from 7.7% to 11.9% and 6.1% to 10.0% in spin-cast and spray-cast devices respectively. We directly attribute this improved device performance to increased thin-film surface coverage coupled with higher optical density. X-ray diffraction studies also reveal that the HI additive facilitates full conversion of the precursor material to the crystalline perovskite phase. From solution studies, we relate these changes in device performance to the presence and distribution of precursor aggregates that effectively pattern the formation of perovskite crystals during film formation

    Sydney Conservatorium of Music Postgraduate Handbook 2009

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    In stage III breast carcinoma, metastasized disease needs to be determined. In the past, conventional imaging by liver ultrasound, chest X-ray and bone scintigraphy was the work-up of choice. Recently, FDG-PET/CT was found to have additional value, but clinicians are hesitant to introduce this technique. We present three patients in whom FDG-PET/CT was applied. A 61-year-old woman with stage III breast carcinoma after conventional work-up was upstaged to stage IV breast carcinoma by FDG-PET/CT, upon which her treatment was changed. A 55-year-old woman suspected of stage IV breast carcinoma after conventional imaging was downstaged to stage III after FDG-PET/CT. Her treatment was changed as well. In a 78-year-old woman with recurrent breast carcinoma, the diagnostic certainty of stage III breast carcinoma was increased by FDG-PET/CT. We conclude that FDG-PET/CT is valuable for adequately diagnosing metastases in patients with stage III breast carcinoma and can replace conventional imaging

    Handling End-of-Life Situations in Small Animal Practice:What Strategies do Veterinarians Contemplate During their Decision-Making Process?

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    This study researched end-of-life (EoL) decision-making processes in small animal practices in the Netherlands, focusing on strategies veterinarians contemplate during this process. Fourteen veterinarians were interviewed about animal end-of-life decision-making. The results of these interviews show that the decision-making process consists of three steps. The first step is to assess the animal’s health and welfare. During the second step, veterinarians consider the position of the owner. Based on steps 1 and 2, veterinarians decide in step 3 whether their advice is to a) euthanize or b) contemplate one or more strategies to come to a decision or potentially alter the decision. These results can support members of the veterinary profession to reflect on their decision-making process. If veterinarians know what strategies their peers use to deal with EoL situations, this can help to reduce the stress they experience in such situations. In addition, veterinarians may find inspiration for new strategies in the study results. For the veterinary profession itself, the current results can be used as a starting point for describing best practices for EoL decision-making in small animal practice.</p

    Handling End-of-Life Situations in Small Animal Practice:What Strategies do Veterinarians Contemplate During their Decision-Making Process?

    Get PDF
    This study researched end-of-life (EoL) decision-making processes in small animal practices in the Netherlands, focusing on strategies veterinarians contemplate during this process. Fourteen veterinarians were interviewed about animal end-of-life decision-making. The results of these interviews show that the decision-making process consists of three steps. The first step is to assess the animal’s health and welfare. During the second step, veterinarians consider the position of the owner. Based on steps 1 and 2, veterinarians decide in step 3 whether their advice is to a) euthanize or b) contemplate one or more strategies to come to a decision or potentially alter the decision. These results can support members of the veterinary profession to reflect on their decision-making process. If veterinarians know what strategies their peers use to deal with EoL situations, this can help to reduce the stress they experience in such situations. In addition, veterinarians may find inspiration for new strategies in the study results. For the veterinary profession itself, the current results can be used as a starting point for describing best practices for EoL decision-making in small animal practice.</p

    Emotions on the loose: emotional contagion and the role of oxytocin in pigs

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    We studied emotional contagion, a simple form of empathy, and the role of oxytocin herein in pigs. Two training pigs per pen (n = 16 pens) were subjected to a positive treatment (pairwise access to a large compartment filled with peat, straw and some chocolate raisins) and a negative treatment (social isolation in a small compartment) in a test room using a within-subjects design. Thereafter, two naive pen mates joined the training pigs in the test room, but were not given access to the treatments. This allowed testing for emotional contagion. Subsequently, the naive pigs, serving as their own controls, were given 24 IU of oxytocin or a placebo intranasally 30 min before accompanying the training pigs, which were exposed to either the negative or positive treatment, to the test room. Behavioral differences found between the positive and negative treatments (e.g., play and “tail wagging” vs. standing alert, urinating, defecating and ears backward) show that the treatments induced a positive and negative emotional state in the training pigs, respectively. Changes in behaviors of the training pigs with and without naive pigs present (e.g., in ears backwards) and of the naive pigs with and without training pigs present (e.g., in standing alert) indicated that emotional contagion occurred, especially during the negative treatment. Oxytocin did not seem to affect the behavior of the treated naive pigs, but did affect behaviors (e.g., defecating) of the training pigs which had not received oxytocin. This suggests a role for oxytocin in pig communication, which merits further research

    Selection Based on Indirect Genetic Effects for Growth, Environmental Enrichment and Coping Style Affect the Immune Status of Pigs

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    Pigs living in intensive husbandry systems may experience both acute and chronic stress through standard management procedures and limitations in their physical and social environment, which may have implications for their immune status. Here, the effect of a new breeding method where pigs were selected on their heritable influence on their pen mates' growth, and environmental enrichment on the immune status of pigs was investigated. Hereto, 240 pigs with a relatively positive genetic effect on the growth of their pen mates (+SBV) and 240 pigs with a relatively negative genetic effect on the growth of their pen mates (-SBV) were housed in barren or straw-enriched pens from 4 to 23 weeks of age (n = 80 pens in total). A blood sample was taken from the pigs before, three days after a 24 h regrouping test, and at week 22. In addition, effects of coping style, as assessed in a backtest, and gender were also investigated. Mainly, +SBV were found to have lower leukocyte, lymphocyte and haptoglobin concentrations than -SBV pigs. Enriched housed pigs had a lower neutrophil to lymphocyte (N:L) ratio and lower haptoglobin concentrations, but had higher antibody titers specific for Keyhole Limpet Hemocyanin (KLH) than barren housed pigs. No interactions were found between SBV class and housing. Furthermore, pigs with a proactive coping style had higher alternative complement activity and, in the enriched pens, higher antibody titers specific for KLH than pigs with a reactive coping style. Lastly, females tended to have lower leukocyte, but higher haptoglobin concentrations than castrated males. Overall, these results suggest that +SBV pigs and enriched housed pigs were less affected by stress than -SBV and barren housed pigs, respectively. Moreover, immune activation might be differently organized in individuals with different coping styles and to a lesser extent in individuals of opposite genders

    Ptychographic electron microscopy using high-angle dark-field scattering for sub-nanometre resolution imaging

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    Diffractive imaging, in which image-forming optics are replaced by an inverse computation using scattered intensity data, could, in principle, realize wavelength-scale resolution in a transmission electron microscope. However, to date all implementations of this approach have suffered from various experimental restrictions. Here we demonstrate a form of diffractive imaging that unshackles the image formation process from the constraints of electron optics, improving resolution over that of the lens used by a factor of five and showing for the first time that it is possible to recover the complex exit wave (in modulus and phase) at atomic resolution, over an unlimited field of view, using low-energy (30 keV) electrons. Our method, called electron ptychography, has no fundamental experimental boundaries: further development of this proof-of-principle could revolutionize sub-atomic scale transmission imaging
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