3,034 research outputs found

    Transformational learning in a first year Western Australian Bachelor of Education primary course

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    In this study the experiences of commencing first year Bachelor of Education (Primary) students were investigated. A mixed methods approach was used consisting of an online survey and 12 questions that were asked in interviews with students who agreed to be interviewed. The online survey data was developed using QualtrixTM software and the results of the survey responses were analysed using the available features in QualtrixTM. The survey responses indicated that students were motivated to become teachers however they found the academic study work load difficult. To accommodate the study load required students to find several hours in an already busy life world consisting of parenting and financial responsibilities. The results of the online survey show strong agreement with the line-by-line coding process applied to the interview responses. Some questions in the online survey were adapted from the First Year Experience Questionnaire for reliability, in particular those relating to Comprehending and Coping. This group of questions together with the 12 interview questions were mapped to selected phases of Mezirow‘s (1991) phases of transformational learning allowing identification of the phases of transformational learning experienced by students. All students experienced one or more phases of transformational learning. Both groups of students surveyed and interviewed were passionate about becoming a Primary School Teacher and valued the support of their families. However, all students reported being overwhelmed by the academic study load. The mature age students reported reduced financial income, child care, being dependent on a spouse and finding it difficult to devote enough time to study at home as significant problems that they believed could determine whether or not they would be able to keep going in the course. School leavers were overwhelmed by the study load and lacked the time management skills to effectively implement a solution to their problems

    Ka-Band Waveguide Three-Way Serial Combiner for MMIC Amplifiers

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    In this innovation, the three-way combiner consists internally of two branch-line hybrids that are connected in series by a short length of waveguide. Each branch-line hybrid is designed to combine input signals that are in phase with an amplitude ratio of two. The combiner is constructed in an E-plane split-block arrangement and is precision machined from blocks of aluminum with standard WR-28 waveguide ports. The port impedances of the combiner are matched to that of a standard WR-28 waveguide. The component parts include the power combiner and the MMIC (monolithic microwave integrated circuit) power amplifiers (PAs). The three-way series power combiner is a six-port device. For basic operation, power that enters ports 3, 5, and 6 is combined in phase and appears at port 1. Ports 2 and 4 are isolated ports. The application of the three-way combiner for combining three PAs with unequal output powers was demonstrated. NASA requires narrow-band solid-state power amplifiers (SSPAs) at Ka-band frequencies with output power in the range of 3 to 5 W for radio or gravity science experiments. In addition, NASA also requires wideband, high-efficiency SSPAs at Ka-band frequencies with output power in the range of 5 to 15 W for high-data-rate communications from deep space to Earth. The three-way power combiner is designed to operate over the frequency band of 31.8 to 32.3 GHz, which is NASA s deep-space frequency band

    HLA gene expression is altered in whole blood and placenta from women who later developed preeclampsia

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    Preeclampsia is a multi-system disease that significantly contributes to maternal and fetal morbidity and mortality. In this study, we used a non-biased microarray approach to identify dysregulated genes in maternal whole blood samples which may be associated with the development of preeclampsia. Whole blood samples were obtained at 28 weeks of gestation from 5 women who later developed preeclampsia (cases) and 10 matched women with normotensive pregnancies (controls). Placenta samples were obtained from an independent cohort of 19 women with preeclampsia matched with 19 women with normotensive pregnancies. We studied gene expression profiles using Illumina microarray in blood and validated changes in gene expression in whole blood and placenta tissue by qPCR. We found a transcriptional profile differentiating cases from controls; 236 genes were significantly dysregulated in blood from women who developed preeclampsia. Functional annotation of microarray results indicated that most of the genes found to be dysregulated were involved in inflammatory pathways. Whilst general trends were preserved, only HLA-A was validated in whole blood samples from cases using qPCR (2.30 ± 0.9 fold change) whereas in placental tissue HLA-DRB1 expression was found to be significantly increased in samples from women with preeclampsia (5.88 ± 2.24 fold change). We have identified that HLA-A is up-regulated in the circulation of women who went on to develop preeclampsia. In placenta of women with preeclampsia we identified that HLA-DRB1 is up-regulated. Our data provide further evidence for involvement of the HLA gene family in the pathogenesis of preeclampsia

    Institutional experience with a rotational total skin electron irradiation (RTSEI) technique—A three decade review (1981–2012)

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    AbstractTotal skin electron irradiation (TSEI) for patients with cutaneous lymphomas is technically challenging, and numerous approaches have been developed to overcome the many field matching problems associated with such a large and complex treatment volume. Since 1981 we have delivered TSEI using a rotational total skin electron irradiation (RTSEI) technique in conjunction with patch, treat and boost fields in order to provide complete skin and dose coverage. Initially we used a 6MeV electron beam at an extended source-skin distance (SSD) on a modified linear accelerator. More recently we began using a high dose rate electron mode on a commercially available linear accelerator. The RTSEI technique allows the delivery of a seamless surface dose to the majority of the patient's skin surface in a single treatment. In this review paper we present our three-decade experience with the technical development, dosimetry, treatment delivery and clinical outcomes of our RTSEI technique

    In vivo safety and efficacy testing of a thermally triggered injectable hydrogel scaffold for bone regeneration and augmentation in a rat model

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    Bone loss resulting from degenerative diseases and trauma is a significant clinical burden which is likely to grow exponentially with the aging population. In a number of conditions where pre-formed materials are clinically inappropriate an injectable bone forming hydrogel could be beneficial. The development of an injectable hydrogel to stimulate bone repair and regeneration would have broad clinical impact and economic benefit in a variety of orthopedic clinical applications. We have previously reported the development of a Laponite® crosslinked pNIPAMco- DMAc (L-pNIPAM-co-DMAc) hydrogel delivery system, loaded with hydroxyapatite nanoparticles (HAPna), which was capable of inducing osteogenic differentiation of mesenchymal stem cells (MSCs) without the need for additional growth factors in vitro. However to enable progression towards clinical acceptability, biocompatibility and efficacy of the L-pNIPAM-co-DMAc hydrogel to induce bone repair in vivo must be determined. Biocompatibility was evaluated by subcutaneous implantation for 6 weeks in rats, and efficacy to augment bone repair was evaluated within a rat femur defect model for 4 weeks. No inflammatory reactions, organ toxicity or systemic toxicity were observed. In young male rats where hydrogel was injected, defect healing was less effective than sham operated controls when rat MSCs were incorporated. Enhanced bone healing was observed however, in aged exbreeder female rats where acellular hydrogel was injected, with increased deposition of collagen type I and Runx2. Integration of the hydrogel with surrounding bone was observed without the need for delivered MSCs; native cell infiltration was also seen and bone formation was observed within all hydrogel systems investigated. This hydrogel can be delivered directly into the target site, is biocompatible, promotes increased bone formation and facilitates migration of cells to promote integration with surrounding bone, for safe and efficacious bone repai

    Mental Health and the Intersectionality of Race and Gender of Crossover Youth

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    Abstract African American youth and their kinship families engaged in dual systems of care (i.e., child welfare system and juvenile justice system) commonly known as “crossover youth” can become overwhelmed by the competing priorities of both systems. While one system purports to advance a best interests standard of children in out of home care, the other, is stated to be centered on tenets of restorative justice. Children and families simultaneously involved in systems that are incompatible can be very difficult to negotiate. In addition to the traditional developmental gaps in crossover youth development there are subsequent layers that contribute to the youth’s identity at the point of intersectionality. The presence of multiple selves and the lack of stability to navigate nuanced personas in these dual systems creates discourse relative to poly-victimization, serial victimization, and betrayal trauma. As a community-based strategy, to address the structural and systemic disconnect of these competing systems in the lives of African American families of crossover youth in kinship care settings, A Second Chance, Inc. (ASCI), a Pennsylvania nonprofit dedicated to kinship care, created a High Intensity Kinship Unit to address these competing systems. ASCI’s In-Home Clinical Service department highlights youth’s mental health concerns while collaborating with the High Impact Unit (HIU) who services to bridge systemic gaps, address the nuances inherent in the child welfare and juvenile justice; and to improve the outcomes for success for African American crossover youth. This article will advance a community-based framework based on the strengths of the Black family. Centered on the frameworks of Critical Race Theory and Self-Efficacy, the aim of this article is to examine strategies used by a community-based agency to address the structural racism of the systems of care, as well as to better understanding the role of self-efficacy when working with youth crossover as it relates to their educational and mental health needs. Lastly, the aim of this manuscript is to provide practical and effective interventions when working with African American crossover youth in kinship care, through a community-based lens

    Gene expression profiling of mammary gland development reveals putative roles for death receptors and immune mediators in post-lactational regression

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    INTRODUCTION: In order to gain a better understanding of the molecular processes that underlie apoptosis and tissue regression in mammary gland, we undertook a large-scale analysis of transcriptional changes during the mouse mammary pregnancy cycle, with emphasis on the transition from lactation to involution. METHOD: Affymetrix microarrays, representing 8618 genes, were used to compare mammary tissue from 12 time points (one virgin, three gestation, three lactation and five involution stages). Six animals were used for each time point. Common patterns of gene expression across all time points were identified and related to biological function. RESULTS: The majority of significantly induced genes in involution were also differentially regulated at earlier stages in the pregnancy cycle. This included a marked increase in inflammatory mediators during involution and at parturition, which correlated with leukaemia inhibitory factor–Stat3 (signal transducer and activator of signalling-3) signalling. Before involution, expected increases in cell proliferation, biosynthesis and metabolism-related genes were observed. During involution, the first 24 hours after weaning was characterized by a transient increase in expression of components of the death receptor pathways of apoptosis, inflammatory cytokines and acute phase response genes. After 24 hours, regulators of intrinsic apoptosis were induced in conjunction with markers of phagocyte activity, matrix proteases, suppressors of neutrophils and soluble components of specific and innate immunity. CONCLUSION: We provide a resource of mouse mammary gene expression data for download or online analysis. Here we highlight the sequential induction of distinct apoptosis pathways in involution and the stimulation of immunomodulatory signals, which probably suppress the potentially damaging effects of a cellular inflammatory response while maintaining an appropriate antimicrobial and phagocytic environment

    Ka-Band Waveguide Two-Way Hybrid Combiner for MMIC Amplifiers

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    The design, simulation, and characterization of a novel Ka-band (32.05 0.25 GHz) rectangular waveguide two-way branch-line hybrid unequal power combiner (with port impedances matched to that of a standard WR-28 waveguide) has been created to combine input signals, which are in phase and with an amplitude ratio of two. The measured return loss and isolation of the branch-line hybrid are better than 22 and 27 dB, respectively. The measured combining efficiency is 92.9 percent at the center frequency of 32.05 GHz. This circuit is efficacious in combining the unequal output power from two Ka-band GaAs pseudomorphic high electron mobility transistor (pHEMT) monolithic microwave integrated circuit (MMIC) power amplifiers (PAs) with high efficiency. The component parts include the branch-line hybrid-based power combiner and the MMIC-based PAs. A two-way branch-line hybrid is a four-port device with all ports matched; power entering port 1 is divided in phase, and into the ratio 2:1 between ports 3 and 4. No power is coupled to port 2. MMICs are a type of integrated circuit fabricated on GaAs that operates at microwave frequencies, and performs the function of signal amplification. The power combiner is designed to operate over the frequency band of 31.8 to 32.3 GHz, which is NASA's deep space frequency band. The power combiner would have an output return loss better than 20 dB. Isolation between the output port and the isolated port is greater than 25 dB. Isolation between the two input ports is greater than 25 dB. The combining efficiency would be greater than 90 percent when the ratio of the two input power levels is two. The power combiner is machined from aluminum with E-plane split-block arrangement, and has excellent reliability. The flexibility of this design allows the combiner to be customized for combining the power from MMIC PAs with an arbitrary power output ratio. In addition, it allows combining a low-power GaAs MMIC with a high-power GaN MMIC. The arbitrary port impedance allows matching the output impedance of the MMIC PA directly to the waveguide impedance without transitioning first into a transmission line with characteristic impedance of 50 ohms. Thus, by eliminating the losses associated with a transition, the overall SSPA efficiency is enhanced. For reducing the cost and weight when required in very large quantities, such as in the beam-forming networks of phased-array antenna systems, the combiner can be manufactured using metal-plated plastic. Two hybrid unequal power combiners can be cascaded to realize a non-binary combiner (for e.g., a three-way) and can be synergistically optimized for low VSWR (voltage standing wave ratio), low insertion loss, high isolation, and wide bandwidth using commercial off-the-shelf electromagnetic software design tools

    High Efficiency Ka-Band Solid State Power Amplifier Waveguide Power Combiner

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    A novel Ka-band high efficiency asymmetric waveguide four-port combiner for coherent combining of two Monolithic Microwave Integrated Circuit (MMIC) Solid State Power Amplifiers (SSPAs) having unequal outputs has been successfully designed, fabricated and characterized over the NASA deep space frequency band from 31.8 to 32.3 GHz. The measured combiner efficiency is greater than 90 percent, the return loss greater than 18 dB and input port isolation greater than 22 dB. The manufactured combiner was designed for an input power ratio of 2:1 but can be custom designed for any arbitrary power ratio. Applications considered are NASA s space communications systems needing 6 to 10 W of radio frequency (RF) power. This Technical Memorandum (TM) is an expanded version of the article recently published in Institute of Engineering and Technology (IET) Electronics Letters

    Ka-Band Waveguide Hybrid Divider with Unequal and Arbitrary Power Output Ratio

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    One or more embodiments of the present invention describe an apparatus and method to combine unequal powers. The apparatus includes a first input port, a second input port, and a combiner. The first input port is operably connected to a first power amplifier and is configured to receive a first power from the first power amplifier. The second input port is operably connected to a second power amplifier and is configured to receive a second power from the second power amplifier. The combiner is configured to simultaneously receive the first power from the first input port and the second power from the second input port. The combiner is also configured to combine the first power and second power to produce a maximized power. The first power and second power are unequal
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