364 research outputs found
Hydrodynamic motion of guiding elements within a magnetic switchyard in fast ignition conditions
Magnetic collimation via resistivity gradients is an innovative approach to electron beam control for the cone-guided fast ignition variant of inertial confinement fusion. This technique uses a resistivity gradient induced magnetic field to collimate the electron beam produced by the high-intensity laser–plasma interaction within a cone-guided fast ignition cone-tip. A variant of the resistive guiding approach, known as the “magnetic switchyard,” has been proposed which uses shaped guiding elements to direct the electrons toward the compressed fuel. Here, the 1D radiation-hydrodynamics code HYADES is used to investigate and quantify the gross hydrodynamic motion of these magnetic switchyard guiding elements in conditions relevant to their use in fast ignition. Movement of the layers was assessed for a range of two-layer material combinations. Based upon the results of the simulations, a scaling law is found that enables the relative extent of hydrodynamic motion to be predicted based upon the material properties of the switchyard, thereby enabling optimization of material-combination choice on the basis of reducing hydrodynamic motion. A multi-layered configuration, more representative of an actual switchyard, was also simulated in which an outer Au layer is employed to tamp the motion of the outermost guiding element of the switchyard
Diet for Wound Healing
Technical Review by Kay Craven, MPH, RDN, LDN, Brody School of Medicine; Matthew Kelly MD, MS, Hyperbaric Specialist, University of Pennsylvania, Philadelphia; Njeri Njuguna MS, RDN, LDN Vidant Medical Center, GreenvilleDiet for wound healing is important but few patient friendly materials are available. Diet for Wound Healing has two parts: 1) detailed background describing the important components of diet for wound healing (5 pages) and 2) a 2 page patient friendly handou
Pro-neural transcription factors as cancer markers.
BACKGROUND: The aberrant transcription in cancer of genes normally associated with embryonic tissue differentiation at various organ sites may be a hallmark of tumour progression. For example, neuroendocrine differentiation is found more commonly in cancers destined to progress, including prostate and lung. We sought to identify proteins which are involved in neuroendocrine differentiation and differentially expressed in aggressive/metastatic tumours. RESULTS: Expression arrays were used to identify up-regulated transcripts in a neuroendocrine (NE) transgenic mouse model of prostate cancer. Amongst these were several genes normally expressed in neural tissues, including the pro-neural transcription factors Ascl1 and Hes6. Using quantitative RT-PCR and immuno-histochemistry we showed that these same genes were highly expressed in castrate resistant, metastatic LNCaP cell-lines. Finally we performed a meta-analysis on expression array datasets from human clinical material. The expression of these pro-neural transcripts effectively segregates metastatic from localised prostate cancer and benign tissue as well as sub-clustering a variety of other human cancers. CONCLUSION: By focussing on transcription factors known to drive normal tissue development and comparing expression signatures for normal and malignant mouse tissues we have identified two transcription factors, Ascl1 and Hes6, which appear effective markers for an aggressive phenotype in all prostate models and tissues examined. We suggest that the aberrant initiation of differentiation programs may confer a selective advantage on cells in all contexts and this approach to identify biomarkers therefore has the potential to uncover proteins equally applicable to pre-clinical and clinical cancer biology.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Feasibility of Tomotherapy-Based Image-Guided Radiotherapy for Locally Advanced Oropharyngeal Cancer
PURPOSE: The study aims to assess the feasibility of tomotherapy-based image-guided (IGRT) radiotherapy for locally advanced oropharyngeal cancer. A retrospective review of 33 patients undergoing concurrent chemoradiation for locally advanced oropharyngeal cancers was conducted. Radiotherapy planning, treatment toxicity and loco-regional control were assessed. RESULTS: At a median follow-up of 32 months (6-47 months), no patient developed loco-regional recurrence. Two patients (6%) developed distant metastases. Grade 3-4 acute toxicity was respectively 72% and 25% for mucositis and gastrointestinal toxicity. Two patients (6%) had long-term dependence on tube feedings. Dose-volume histogram demonstrated excellent target volume coverage and low radiation dose to the organs at risk for complications. CONCLUSIONS AND CLINICAL RELEVANCE: IGRT provides excellent loco-regional control but acute toxicity remains significant and needs to be addressed in future prospective trials. The feasibility of Tomotherapy to decrease radiation dose to the normal tissues merits further investigations
Feasibility of image-guided radiotherapy based on helical tomotherapy to reduce contralateral parotid dose in head and neck cancer
Background
To evaluate the feasibility of image-guided radiotherapy based on helical Tomotherapy to spare the contralateral parotid gland in head and neck cancer patients with unilateral or no neck node metastases.
Methods
A retrospective review of 52 patients undergoing radiotherapy for head and neck cancers with image guidance based on daily megavoltage CT imaging with helical tomotherapy was performed.
Results
Mean contralateral parotid dose and the volume of the contralateral parotid receiving 40 Gy or more were compared between radiotherapy plans with significant constraint (SC) of less than 20 Gy on parotid dose (23 patients) and the conventional constraint (CC) of 26 Gy (29 patients). All patients had PTV coverage of at least 95% to the contralateral elective neck nodes. Mean contralateral parotid dose was, respectively, 14.1 Gy and 24.7 Gy for the SC and CC plans (p < 0.0001). The volume of contralateral parotid receiving 40 Gy or more was respectively 5.3% and 18.2% (p < 0.0001)
Conclusion
Tomotherapy for head and neck cancer minimized radiotherapy dose to the contralateral parotid gland in patients undergoing elective node irradiation without sacrificing target coverage
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Bangladeshi women's experiences of infant feeding in the London Borough of Tower Hamlets.
This study examined the main factors that influence Bangladeshi women living in London's decisions to partially breastfeed their children, including the influence of older women within the community. Fifty-seven women of Bangladeshi origin living in the London Borough of Tower Hamlets took part in seven discussion groups between April and June 2013. Five groups were held with women of child-bearing age and two groups with older women in the community. A further eight younger women and three older women took part in one-on-one interviews. Interviews were also carried out with eight local health care workers, including public health specialists, peer support workers, breastfeeding coordinators and a health visitor. The influences on women's infant feeding choices can be understood through a 'socio-ecological model', including public health policy; diverse cultural influences from Bangladesh, London and the Bangladeshi community in London; and the impacts of migration and religious and family beliefs. The women's commitment to breastfeeding was mediated through the complexity of their everyday lives. The tension between what was 'best' and what was 'possible' leads them not only to partially breastfeed but also to sustain partial breastfeeding in a way not seen in other socio-cultural groups in the United Kingdom
Technology-Supported Storytelling (TSST) Strategy in Virtual World for Multicultural Education
Learning culture through stories is an effective way for multicultural education, since stories are one of the most powerful and personal ways that we learn about the world. Storytelling, the process of telling stories, is a form of communication and a universal expression of culture. With the development of technology, storytelling emerges out of diverse ways. This study explores the storytelling in virtual worlds for multicultural education, and devises a Technology-Supported storytelling (TSST) strategy by examining and considering the characteristics of virtual worlds which could be incorporated into the storytelling, and then uses this strategy to teach Korean culture to students with different culture background. With this innovative TSST strategy in virtual world, this study expects to provide a guide to practice for teaching multicultural in digital era
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An examination of factors influencing the choice of therapy for patients with coronary artery disease
BACKGROUND: A diverse range of factors influence clinicians' decisions regarding the allocation of patients to different treatments for coronary artery disease in routine cardiology clinics. These include demographic measures, risk factors, co-morbidities, measures of objective cardiac disease, symptom reports and functional limitations. This study examined which of these factors differentiated patients receiving angioplasty from medication; bypass surgery from medication; and bypass surgery from angioplasty. METHODS: Univariate and multivariate logistic regression analyses were conducted on patient data from 214 coronary artery disease patients who at the time of recruitment had been received a clinical assessment and were reviewed by their cardiologist in order to determine the form of treatment they were to undergo: 70 would receive/continue medication, 71 were to undergo angioplasty and 73 were to undergo bypass surgery. RESULTS: Analyses differentiating patients receiving angioplasty from medication produced 9 significant univariate predictors, of which 5 were also multivariately significant (left anterior descending artery disease, previous coronary interventions, age, hypertension and frequency of angina). The analyses differentiating patients receiving surgery from angioplasty produced 12 significant univariate predictors, of which 4 were multivariately significant (limitations in mobility range, circumflex artery disease, previous coronary interventions and educational level). The analyses differentiating patients receiving surgery from medication produced 14 significant univariate predictors, of which 4 were multivariately significant (left anterior descending artery disease, previous cerebral events, limitations in mobility range and circumflex artery disease). CONCLUSION: Variables emphasised in clinical guidelines are clearly involved in coronary artery disease treatment decisions. However, variables beyond these may also be important factors when therapy decisions are undertaken thus their roles require further investigation
Dynamical Zodiacal Cloud Models Constrained by High Resolution Spectroscopy of the Zodiacal Light (Icarus, in press)
The simulated Doppler shifts of the solar Mg I Fraunhofer line produced by
scattering on the solar light by asteroidal, cometary, and trans-Neptunian dust
particles are compared with the shifts obtained by Wisconsin H-Alpha Mapper
(WHAM) spectrometer. The simulated spectra are based on the results of
integrations of the orbital evolution of particles. The deviation of the
derived spectral parameters for various sources of dust used in the model
reached maximum at the elongation (measured eastward from the Sun) between 90
deg and 120 deg. For the future zodiacal light Doppler shifts measurements, it
is important to pay a particular attention to observing at this elongation
range. At the elongations of the fields observed by WHAM, the model-predicted
Doppler shifts were close to each other for several scattering functions
considered. Therefore the main conclusions of our paper don't depend on a
scattering function and mass distribution of particles if they are reasonable.
A comparison of the dependencies of the Doppler shifts on solar elongation and
the mean width of the Mg I line modeled for different sources of dust with
those obtained from the WHAM observations shows that the fraction of cometary
particles in zodiacal dust is significant and can be dominant. Cometary
particles originating inside Jupiter's orbit and particles originating beyond
Jupiter's orbit (including trans-Neptunian dust particles) can contribute to
zodiacal dust about 1/3 each, with a possible deviation from 1/3 up to 0.1-0.2.
The fraction of asteroidal dust is estimated to be about 0.3-0.5. The mean
eccentricities of zodiacal particles located at 1-2 AU from the Sun that better
fit the WHAM observations are between 0.2 and 0.5, with a more probable value
of about 0.3.Comment: Icarus, in pres
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