458 research outputs found

    Radiation-induced cardiac side-effects:The lung as target for interacting damage and intervention

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    Radiotherapy is part of the treatment for many thoracic cancers. During this treatment heart and lung tissue can often receive considerable doses of radiation. Doses to the heart can potentially lead to cardiac effects such as pericarditis and myocardial fibrosis. Common side effects after lung irradiation are pneumonitis and pulmonary fibrosis. It has also been shown that lung irradiation has effects on cardiac function. In a rat model lung irradiation caused remodeling of the pulmonary vasculature increasing resistance of the pulmonary vascular bed, leading to enhanced pulmonary artery pressure, right ventricle hypertrophy and reduced right ventricle performance. Even more pronounced effects are observed when both, lung and heart are irradiated. The effects observed after lung irradiation show striking similarities with symptoms of pulmonary arterial hypertension. In particular, the vascular remodeling in lung tissue seems to have similar underlying features. Here, we discuss the similarities and differences of vascular remodeling observed after thoracic irradiation compared to those in pulmonary arterial hypertension patients and research models. We will also assess how this knowledge of similarities could potentially be translated into interventions which would be beneficial for patients treated for thoracic tumors, where dose to lung tissue is often unavoidable

    Radiation-induced cardiac side-effects: The lung as target for interacting damage and intervention

    Get PDF
    Radiotherapy is part of the treatment for many thoracic cancers. During this treatment heart and lung tissue can often receive considerable doses of radiation. Doses to the heart can potentially lead to cardiac effects such as pericarditis and myocardial fibrosis. Common side effects after lung irradiation are pneumonitis and pulmonary fibrosis. It has also been shown that lung irradiation has effects on cardiac function. In a rat model lung irradiation caused remodeling of the pulmonary vasculature increasing resistance of the pulmonary vascular bed, leading to enhanced pulmonary artery pressure, right ventricle hypertrophy and reduced right ventricle performance. Even more pronounced effects are observed when both, lung and heart are irradiated.The effects observed after lung irradiation show striking similarities with symptoms of pulmonary arterial hypertension. In particular, the vascular remodeling in lung tissue seems to have similar underlying features. Here, we discuss the similarities and differences of vascular remodeling observed after thoracic irradiation compared to those in pulmonary arterial hypertension patients and research models. We will also assess how this knowledge of similarities could potentially be translated into interventions which would be beneficial for patients treated for thoracic tumors, where dose to lung tissue is often unavoidable

    Strategizing as multi-modal and rhetorical discursive practice: a case study of the BHP Billiton's failed acquisition of Rio Tinto

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    This thesis took a discourse approach to analyze BHP Billiton’s failed acquisition of Rio Tinto in 2007-08 to better understand what happens during strategizing. The research highlighted the structure and dynamics of the discourse, as well as the role of time and context in the social construction of meaning in strategizing. In doing so, the thesis provided new insights into how actors were able to influence such important strategic events. The thesis adopted a multi-modal discourse analytic framework and analyzed media reports, corporate videos, press releases and communications to shareholders, as well as slides and full transcripts of key presentations by both BHP and Rio leadership. The analysis identified the main internal and external actors as either decision-makers (BHP’s leadership, shareholders, competition regulators) or influencers (Rio’s leadership, analysts, media, customers). It further identified a range of multi-modal discursive practices and rhetorical strategies that were brought to bear to negotiate the meaning of three key constructs that shaped the discourse, that is, the additional value pool, the fair share exchange ratio, and the impact on competition. Further, the findings showed how time and context were discursively constructed and influenced the meaning of the three key constructs. These findings enabled a number of contributions to the discourse and M&A literature. While most research into acquisition discourses has routinely ignored the pre-acquisition discourse, this thesis focused on the period preceding the transaction. An initial contribution was to show that, in a pre-acquisition discourse, external actors were not a passive audience but played a significant role as rhetor and audience. Also, while previous empirical studies of discourse have emphasized the role of language, this thesis considered multi-modal discursive practices, including speech, writing, imagery, location and calculative devices. The thesis made a further contribution by showing how actors worked to persuade each other through multi-layered rhetorical strategies that were also brought to bear through non-linguistic modes. This contribution was extended by showing how these practices functioned as transgression markers that signaled convergence or divergence of meaning of the key constructs. A detailed analysis of calculative devices enabled further contributions. An initial contribution was that it showed how calculative devices developed as boundary objects over four stages: identification, calculation, negotiation, and objectification. Further, the thesis showed how calculative devices were imbued with logos and ethos through, for example, the calculative logic, accounting standards and data sources that were woven together in the symbolic manipulations of the device. Lastly, the thesis showed how calculative devices acted as boundary objects, and made a contribution to theory by proposing a third criterion, legitimacy, to complement widely acknowledged criteria of adaptability and commonality. In addition to these dynamics, the thesis outlined a discursive epistemology of strategizing through its analysis of the role of time and context in the social construction of meaning in strategizing. While the role of time and context is widely acknowledged in organizational discourse, it remained unclear what was specific to strategizing. The thesis argued that the purpose of strategizing is to construct and negotiate new or improved options for a preferred future and the actions to bring this about, and made a contribution to a discursive epistemology of strategizing by showing how temporal and contextual work in strategizing extends the horizon of discourses that relate to the future and discourses that relate to the broader discourse. This reconstructs the tapestry of interwoven discourses that make up the local strategy discourse, and creates new strategic options

    Recurrent scoliosis one year after surgical correction

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    A year after anterolateral spondylodesis for progressive scoliosis, the patient showed a flexion gait pattern with recurrent deformity, due to late infection. Surgical debridement resolved all symptoms. Whereas most postoperative infections occur after posterior spondylodesis and present with back pain and mild increase of infection parameters, late infection after anterolateral approach is rare. In this case the patient did not present with the classic symptoms

    Carbon ion induced vascular damage in the rat lung

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    A new CT-based method to quantify radiation-induced lung damage in patients

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    SummaryA new method to assess radiation-induced lung toxicity (RILT) using CT-scans was developed. It is more sensitive in detecting damage and corresponds better to physician-rated radiation pneumonitis than routinely-used methods. Use of this method may improve lung toxicity assessment and thereby facilitate development of more accurate predictive models for RILT

    The impact of cessation or continuation of family violence on children

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    Children exposed to family violence are at risk for developing long-lasting problems. Family violence is a pervasive problem, however, studies comparing continuation with cessation of family violence are limited. Understanding the cessation or continuation of family violence on child development is a prerequisite to prevent enduring problems and develop interventions. This study compares posttraumatic stress and delinquent behavior of children aged between eight and eighteen years for whom severe violence continues to children for whom violence diminishes or ceases. Children (N = 162, 43% boys, mean age 12 years) and their parents reported to child protection services (CPS) with severe violence were included. Levels of family violence, posttraumatic stress and delinquent behavior were re-assessed after 18 months. Most families (74%) still experienced severe family violence at the second assessment despite involvement of CPS. Structural equation modelling was applied. In the group where violence diminished or stopped, delinquent behavior decreased. A decrease of posttraumatic stress only occurred when violence diminished but surprisingly no decrease was observed when violence stopped completely. The findings demonstrate that overall family violence is persistent. Differing paths can be discerned for delinquent behavior and posttraumatic stress, indicating different developmental and recovery pathways after cessation of family violence. Nonetheless, it is fair to state that specialized and long-term care is crucial

    Establishment of the New Particle Therapy Research Center (PARTREC) at UMCG Groningen

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    After 25 years of successful research in the nuclear and radiation physics domain, the KVI-CART research center in Groningen is upgraded and re-established as the PARticle Therapy REsearch Center (PARTREC). Using the superconducting cyclotron AGOR and being embedded within the University Medical Center Groningen, it operates in close collaboration with the Groningen Proton Therapy Center. PARTREC uniquely combines radiation physics, medical physics, biology and radiotherapy research with an R&D program to improve hadron therapy technology and advanced radiation therapy for cancer. A number of further upgrades, scheduled for completion in 2023, will establish a wide range of irradiation modalities, such as pencil beam scanning, shoot-through with high energy protons and SOBP for protons, helium and carbon ions. Delivery of spatial fractionation (GRID) and dose rates over 300 Gy/s (FLASH) are envisioned. In addition, PARTREC delivers a variety of ion beams and infrastructure for radiation hardness experiments conducted by scientific and commercial communities, and nuclear science research in collaboration with the Faculty of Science and Engineering of the University of Groningen
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