A plug-and-play ripple mitigation approach for DC-links in hybrid systems

© 2016 IEEE.In this paper, a plug-and-play ripple mitigation technique is proposed. It requires only the sensing of the DC-link voltage and can operate fully independently to remove the low-frequency voltage ripple. The proposed technique is nonintrusive to the existing hardware and enables hot-swap operation without disrupting the normal functionality of the existing power system. It is user-friendly, modular and suitable for plug-and-play operation. The experimental results demonstrate the effectiveness of the ripple-mitigation capability of the proposed device. The DC-link voltage ripple in a 110 W miniature hybrid system comprising an AC/DC converter and two resistive loads is shown to be significantly reduced from 61 V to only 3.3 V. Moreover, it is shown that with the proposed device, the system reliability has been improved by alleviating the components' thermal stresses

The omohyoid sling syndrome

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Understand How Children Cope with the Diagnosis and Treatment of Cancer: An Important Step to Implement Appropriate Psychological Interventions

Poster Presentation (Nurse's Session)Introduction: Understanding how children cope with the diagnosis and treatment of cancer is a crucial step toward designing appropriate psycho-educational interventions. This paper aimed to explore how Hong Kong Chinese children cope with the diagnosis and treatment of cancer, an area of research that has been underrepresented in existing literature. Methods: A cross-sectional study was employed. Eightyeight Hong Kong Chinese children aged 9 to 16 years, admitted for treatment of cancer in 2 paediatric oncology units, were invited to participate in the study. A one-to-one short interview was conducted. Content analysis was used to analyze the interview data. The differences in coping strategies used between children's sex and age group were assessed by using chi-square test. Results: Findings from this study indicated that the most commonly reported coping strategy used by Hong Kong Chinese children was self-control (emotion-focused). This finding is incongruent with previous studies on Western children in which it was found that seeking social support (problem-focused) was the most commonly reported coping strategy. On the other hand, this study revealed that children used different coping strategies at different developmental stages, with younger children used less problem-focused and more emotionfocused coping strategies than older children. Discussion: The diagnosis and treatment of childhood cancer have been described as extremely stressful and threatening experiences in the life of a child. This study has addressed a gap in the literature by examining how Hong Kong Chinese children coped with and responded to the diagnosis and treatment of cancer. It is anticipated that the information derived from this study would help nurses to shape and design appropriate psycho-educational interventions that can help ease the burden of cancer treatment and provide support for childhood cancer survivors to flight cancer and its subsequent adverse treatment effects at every step of their long and difficult journey.published_or_final_versio

Electronic states of epitaxial thin films of La0.9Sn0.1MnO3 and La0.9Ca0.1MnO3

Structure, transport properties, and electronic structure of epitaxial thin films La0.9Sn0.1MnO3 and La0.9Ca0.1MnO3 have been experimentally studied. According to the Hall-effect measurement, La0.9Sn0.1MnO3 is an n-type conductor in the metallic state due to the substitution of Sn for La. X-ray photoelectron spectroscopy spectra revealed a shift of the Fermi level and the Mn ionic core level of La0.9Sn0.1MnO3 in comparison with La0.9Ca0.1MnO3. The difference between the Mn-2p spectra of La0.9Sn0.1MnO3 and La0.9Ca0.1MnO3 implies that Mn ions in the former are at a Mn2+/Mn3+ mixed-valence state, which is significantly different from the divalent-element-doped manganese oxides, where the Mn ions are in the mixed-valence state of Mn3+/Mn4+.published_or_final_versio

An assessment of the mechanical strengths of aluminide-based thin coatings

Titanium aluminide and nickel aluminide-based thin coatings were synthesized by magnetron sputtering from intermetallic TiAl and Ni3Al alloy targets on nickel substrates. Both types of aluminide coating exhibited high surface hardness values that varied with the degree of heat treatment. The hardness of the coatings was investigated using micro- and nano- indentation techniques. In order to estimate the intrinsic strength of the films, the indentation size effects of the apparent hardness were analyzed by the Jönsson-Hogmark model and a model recently proposed by the authors. The analysis indicated that the strengths of the aluminide coatings may considerably exceed their strengths in bulk.published_or_final_versio

A design methodology for smart LED lighting systems powered by weakly regulated renewable power grids

The increasing use of intermittent renewable energy sources to decarbonize electric power generation is expected to introduce dynamic instability to the mains. This situation is of particular concern for mini-grids or isolated grids in which wind and/or solar power sources are the dominant or the sole power sources. In this paper, we utilize the photo-electro-thermal theory to develop a design methodology for LED lighting systems for weakly regulated voltage sources, with the objectives of minimizing the fluctuation of the human luminous perception and adopting reliable LED driver with long lifetime and robustness against extreme weather conditions. The proposed LED system, practically verified in a 10 kVA small power grid driven by an ac voltage source and a wind energy simulator, can be considered as a smart load with its load demand following the power generation. A typical swing of 40 V in the mains will cause only 15% actual light variation in a 132 W LED system when compared with 40% change in 150 W high-pressure-sodium lamp system. The design methodology enables future large-scale LED systems to be designed as a new generation of smart loads that can adapt to the voltage and power fluctuations arising from the intermittent nature of renewable energy sources. © 2011 IEEE.published_or_final_versio

Mössbauer hyperfine parameters of iron species in the course of Geobacter-mediated magnetite mineralization

Amorphous ferric iron species (ferrihydrite or akaganeite of <5 nm in size) is the only known solid ferric iron oxide that can be reductively transformed by dissimilatory iron-reducing bacteria to magnetite completely. The lepidocrocite crystallite can be transformed into magnetite in the presence of abiotic Fe(II) at elevated pH or biogenic Fe(II) with particular growth conditions. The reduction of lepidocrocite by dissimilatory iron-reducing bacteria has been widely investigated showing varying results. Vali et al. (Proc Natl Acad Sci USA 101:16121-16126, 2004) captured a unique biologically mediated mineralization pathway where the amorphous hydrous ferric oxide transformed to lepidocrocite was followed by the complete reduction of lepidocrocite to single-domain magnetite. Here, we report the 57Fe Mössbauer hyperfine parameters of the time-course samples reported in Vali et al. (Proc Natl Acad Sci USA 101:16121-16126, 2004). Both the quadrupole splittings and linewidths of Fe(III) ions decrease consistently with the change of aqueous Fe(II) and transformations of mineral phases, showing the Fe(II)-mediated gradual regulation of the distorted coordination polyhedrons of Fe 3+ during the biomineralization process. The aqueous Fe(II) catalyzes the transformations of Fe(III) minerals but does not enter the mineral structures until the mineralization of magnetite. The simulated abiotic reaction between Fe(II) and lepidocrocite in pH-buffered, anaerobic media shows the simultaneous formation of green rust and its gradual transformation to magnetite plus a small fraction of goethite. We suggested that the dynamics of Fe(II) supply is a critical factor for the mineral transformation in the dissimilatory iron-reducing cultures. © 2011 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

Lutein enhances survival and reduces neuronal damage in cerebral and retinal ischemia/reperfusion injury

Poster session 3: NeuroprotectionConference theme: Translational Neuroscience: From Molecules To ManPurpose Stroke is one of the leading causes of death worldwide. Protective agents that could diminish the injuries induced by cerebral ischemia/reperfusion (I/R) are crucial to alleviate the detrimental outcome of stroke. Retinal I/R also occurs in many ocular diseases and leads to neuronal death and therefore blindness. Lutein, a safe and potent antioxidant, is known to protect the retina in age-related macular degeneration. The aim of this study is to investigate the protective roles of lutein in cerebral and retinal I/R injury. Methods Two-hour cerebral ischemia was induced by unilateral middle cerebral artery occlusion (MCAo) in mice. Either lutein (0.2mg/kg) or vehicle was given to mice intraperitoneally 1hr after MCAo and 1hr after reperfusion. Neurological deficits were evaluated at 22hr after reperfusion while survival rate was assessed daily until 7 days after reperfusion. Flash electroretinogram (flash ERG) was taken to assess retinal function. After sacrifice, mouse brains were cut into 2mm-thick coronal slices and stained with 2% 2,3,5-triphenyltetrazolium chloride to determine the infarct size after MCAo. Eyes were also enucleated. Paraffin-embedded brain and retinal sections were prepared for TUNEL assay and immunohistochemistry. Protein lysate was collected for Western blotting experiments. Lutein's effect on Müller cells was further evaluated using a model of cobalt chloride-induced hypoxia in immortalized rat Müller cells (rMC-1). Results Higher survival rate, better neurological scores, smaller infarct area and smaller infarct volume were noted in the lutein-treated group. Immunohistochemistry data showed a decrease of immunoreactivity of nitrotyrosine, poly(ADP-ribose) and NFkB in the lutein-treated brains. Western blotting data showed decreased levels of Cox-2, pERK, and pIkB, but increased levels of Bcl-2, heat shock protein 70 and pAkt in the lutein-treated brains. In the retina, severe cell loss in retinal ganglion cell (RGC) layer was noted after I/R injury. Increased oxidative stress was observed in the injured retina. Lutein treatment protected RGC as well as decreased oxidative stress in I/R retina. Lutein treatment also minimized the deterioration of b-wave/a-wave ratio and oscillatory potentials in flash ERG as well as inhibited the up-regulation of GFAP in retinal I/R injury. In the cultured Müller cells, lutein treatment reduced level of nuclear NF-kB together with decreased levels of IL-1b and Cox- 2. Conclusions Post-treatment of lutein protected both the brain and retina from I/R injury. The neuroprotective effect of lutein was associated with reduced oxidative stress. Less production of pro-inflammatory factors from Müller cells suggested an anti-inflammatory role of lutein in retinal ischemic/hypoxic injury. Our results suggest that lutein could diminish the deleterious outcomes of cerebral and retinal I/R probably by its antiapoptotic, anti-oxidative and anti-inflammatory properties. Lutein may have a therapeutic role in protecting the brain in stroke and inner retina in eye diseases with acute ischemia.published_or_final_versio

Detecting dynamic communities in opportunistic networks

In opportunistic networks, communities of mobile entities may be utilized to improve the efficiency of message forwarding. However, identifying communities that are dynamically changing in mobile environment is non-trivial. Based on random walk on graphs, in this paper we present a community detection algorithm that takes into account the aging and weight of contacts between mobile entities. Our idea originates from message-forwarding operations in opportunistic networks. We evaluate the algorithm on both computer-generated networks and real-world human mobility traces. The result shows that our proposed algorithm can find the communities and detect the changes in their structures over time. © 2009 IEEE.published_or_final_versionThe 1st International Conference on Ubiquitous and Future Networks (ICUFN 2009), Hong Kong, China, 7-9 June 2009. In Proceedings of the 1st ICUFN, 2009, p. 159-16

The impact of cancer on children's physical, emotional, and psychosocial well-being

The diagnosis and treatment of cancer are a stressful and threatening experience, which can be emotionally devastating to children. Despite the improved prognosis, the course of cancer treatment has tremendous impact on children. This article aims to examine the impact of cancer on physical, emotional, and psychosocial well-being of Hong Kong Chinese children, an area of research that has been underrepresented in the literature. Ninety-eight Hong Kong Chinese children aged 7 to 15 years, admitted for treatment of cancer in 2 pediatric oncology units of 2 different hospitals, were invited to participate in the study. Findings from this study indicated that the children scored considerably high state anxiety on admission, and more than half of the participants presented some depressive symptoms during their stay in the hospital. Moreover, semistructured interviews indicated that nearly all children expressed different degrees of sadness and worry. The findings suggested that there is a room for improvement in existing nursing intervention regarding preparing children for hospitalization and treatment of cancer. There is an imperative need for nurses to evaluate appropriate nursing interventions that can help children resume their normal growth and development, in particular, to help them ease the physical, emotional, and psychological burden of life-threatening disease. © 2010 Lippincott Williams & Wilkins.postprin