310 research outputs found

    Towards sustainable human space exploration—priorities for radiation research to quantify and mitigate radiation risks

    Full text link
    Human spaceflight is entering a new era of sustainable human space exploration. By 2030 humans will regularly fly to the Moon’s orbit, return to the Moon’s surface and preparations for crewed Mars missions will intensify. In planning these undertakings, several challenges will need to be addressed in order to ensure the safety of astronauts during their space travels. One of the important challenges to overcome, that could be a major showstopper of the space endeavor, is the exposure to the space radiation environment. There is an urgent need for quantifying, managing and limiting the detrimental health risks and electronics damage induced by space radiation exposure. Such risks raise key priority topics for space research programs. Risk limitation involves obtaining a better understanding of space weather phenomena and the complex radiation environment in spaceflight, as well as developing and applying accurate dosimetric instruments, understanding related short- and long-term health risks, and strategies for effective countermeasures to minimize both exposure to space radiation and the remaining effects post exposure. The ESA/SciSpacE Space Radiation White Paper identifies those topics and underlines priorities for future research and development, to enable safe human and robotic exploration of space beyond Low Earth Orbit

    Evaluating the successful implementation of evidence into practice using the PARiHS framework : theoretical and practical challenges

    Get PDF
    Background The PARiHS framework (Promoting Action on Research Implementation in Health Services) has proved to be a useful practical and conceptual heuristic for many researchers and practitioners in framing their research or knowledge translation endeavours. However, as a conceptual framework it still remains untested and therefore its contribution to the overall development and testing of theory in the field of implementation science is largely unquantified. Discussion This being the case, the paper provides an integrated summary of our conceptual and theoretical thinking so far and introduces a typology (derived from social policy analysis) used to distinguish between the terms conceptual framework, theory and model – important definitional and conceptual issues in trying to refine theoretical and methodological approaches to knowledge translation. Secondly, the paper describes the next phase of our work, in particular concentrating on the conceptual thinking and mapping that has led to the generation of the hypothesis that the PARiHS framework is best utilised as a two-stage process: as a preliminary (diagnostic and evaluative) measure of the elements and sub-elements of evidence (E) and context (C), and then using the aggregated data from these measures to determine the most appropriate facilitation method. The exact nature of the intervention is thus determined by the specific actors in the specific context at a specific time and place. In the process of refining this next phase of our work, we have had to consider the wider issues around the use of theories to inform and shape our research activity; the ongoing challenges of developing robust and sensitive measures; facilitation as an intervention for getting research into practice; and finally to note how the current debates around evidence into practice are adopting wider notions that fit innovations more generally. Summary The paper concludes by suggesting that the future direction of the work on the PARiHS framework is to develop a two-stage diagnostic and evaluative approach, where the intervention is shaped and moulded by the information gathered about the specific situation and from participating stakeholders. In order to expedite the generation of new evidence and testing of emerging theories, we suggest the formation of an international research implementation science collaborative that can systematically collect and analyse experiences of using and testing the PARiHS framework and similar conceptual and theoretical approaches. We also recommend further refinement of the definitions around conceptual framework, theory, and model, suggesting a wider discussion that embraces multiple epistemological and ontological perspectives

    Molecular subtype analysis determines the association of advanced breast cancer in Egypt with favorable biology

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Prognostic markers and molecular breast cancer subtypes reflect underlying biological tumor behavior and are important for patient management. Compared to Western countries, women in North Africa are less likely to be prognosticated and treated based on well-characterized markers such as the estrogen receptor (ER), progesterone receptor (PR) and Her2. We conducted this study to determine the prevalence of breast cancer molecular subtypes in the North African country of Egypt as a measure of underlying biological characteristics driving tumor manifestations.</p> <p>Methods</p> <p>To determine molecular subtypes we characterized over 200 tumor specimens obtained from Egypt by performing ER, PR, Her2, CK5/6, EGFR and Ki67 immunohistochemistry.</p> <p>Results</p> <p>Our study demonstrated that the Luminal A subtype, associated with favorable prognosis, was found in nearly 45% of cases examined. However, the basal-like subtype, associated with poor prognosis, was found in 11% of cases. These findings are in sharp contrast to other parts of Africa in which the basal-like subtype is over-represented.</p> <p>Conclusions</p> <p>Egyptians appear to have favorable underlying biology, albeit having advanced disease at diagnosis. These data suggest that Egyptians would largely profit from early detection of their disease. Intervention at the public health level, including education on the benefits of early detection is necessary and would likely have tremendous impact on breast cancer outcome in Egypt.</p

    Bayesian mapping of pulmonary tuberculosis in Antananarivo, Madagascar

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Tuberculosis (TB), an infectious disease caused by the <it>Mycobacterium tuberculosis </it>is endemic in Madagascar. The capital, Antananarivo is the most seriously affected area. TB had a non-random spatial distribution in this setting, with clustering in the poorer areas. The aim of this study was to explore this pattern further by a Bayesian approach, and to measure the associations between the spatial variation of TB risk and national control program indicators for all neighbourhoods.</p> <p>Methods</p> <p>Combination of a Bayesian approach and a generalized linear mixed model (GLMM) was developed to produce smooth risk maps of TB and to model relationships between TB new cases and national TB control program indicators. The TB new cases were collected from records of the 16 Tuberculosis Diagnostic and Treatment Centres (DTC) of the city from 2004 to 2006. And five TB indicators were considered in the analysis: number of cases undergoing retreatment, number of patients with treatment failure and those suffering relapse after the completion of treatment, number of households with more than one case, number of patients lost to follow-up, and proximity to a DTC.</p> <p>Results</p> <p>In Antananarivo, 43.23% of the neighbourhoods had a standardized incidence ratio (SIR) above 1, of which 19.28% with a TB risk significantly higher than the average. Identified high TB risk areas were clustered and the distribution of TB was found to be associated mainly with the number of patients lost to follow-up (SIR: 1.10, CI 95%: 1.02-1.19) and the number of households with more than one case (SIR: 1.13, CI 95%: 1.03-1.24).</p> <p>Conclusion</p> <p>The spatial pattern of TB in Antananarivo and the contribution of national control program indicators to this pattern highlight the importance of the data recorded in the TB registry and the use of spatial approaches for assessing the epidemiological situation for TB. Including these variables into the model increases the reproducibility, as these data are already available for individual DTCs. These findings may also be useful for guiding decisions related to disease control strategies.</p

    8000 years of North Atlantic storminess reconstructed from a Scottish peat record: implications for Holocene atmospheric circulation patterns in Western Europe

    Get PDF
    North Atlantic storminess can affect human settlements, infrastructure and transport links, all of which strongly impact local, national and global economies. An increase in storm frequency and intensity is predicted over the North-East Atlantic in the 21st century because of a northward shift in storm tracks and a persistently positive North Atlantic Oscillation (NAO), driven by recent atmospheric warming. Although documentary records of North Atlantic storminess exist, these are generally limited to the last c. 1000 years. This paper presents a continuous high-resolution proxy record of storminess spanning the last 8000 years from a 6&thinsp;m-long core taken from a peat bog in northern Scotland. Bromine concentrations in the peat, derived from sea spray, are used to reconstruct storm frequency and storm intensity, and mire surface wetness is used as an indicator of longer-term climate shifts. The results suggest a relationship between positive phases of the NAO and increased North Atlantic storminess. However, subtle differences between bromine concentrations and mire surface wetness suggest that high-intensity but perhaps less frequent periods of storminess are not necessarily associated with a wetter climate

    Modifications in host cell cytoskeleton structure and function mediated by intracellular HIV-1 Tat protein are greatly dependent on the second coding exon

    Get PDF
    Supplementary Data are available at NAR OnlineThe human immunodeficiency virus type 1 (HIV-1) regulator Tat is essential for viral replication because it achieves complete elongation of viral transcripts. Tat can be released to the extracellular space and taken up by adjacent cells, exerting profound cytoskeleton rearrangements that lead to apoptosis. In contrast, intracellular Tat has been described as protector from apoptosis. Tat gene is composed by two coding exons that yield a protein of 101 amino acids (aa). First exon (1–72aa) is sufficient for viral transcript elongation and second exon (73–101 aa) appears to contribute to non-transcriptional functions. We observed that Jurkat cells stably expressing intracellular Tat101 showed gene expression deregulation 4-fold higher than cells expressing Tat72. Functional experiments were performed to evaluate the effect of this deregulation. First, NF-iB-, NF-AT- and Sp1-dependent transcriptional activities were greatly enhanced in Jurkat-Tat101, whereas Tat72 induced milder but efficient activation. Second, cytoskeleton-related functions as cell morphology, proliferation, chemotaxis, polarization and actin polymerization were deeply altered in Jurkat- Tat101, but not in Jurkat-Tat72. Finally, expression of several cell surface receptors was dramatically impaired by intracellular Tat101 but not by Tat72. Consequently, these modifications were greatly dependent on Tat second exon and they could be related to the anergy observed in HIV-1-infected T cells.Plan Nacional del SIDA (MVI 1434/05–5), FIPSE 36584/ 06 and 36633/07, VIRHORST Network from Comunidad de Madrid (Spain), FIS PI040614 and PI0808752, ISCIII-RETIC RD06/0006, EUROPRISE Network of Excellence of the EU (Grant no. LSHP CT-2006- 037611), and BIO2008-04384 from the Ministerio de Ciencia e Innovacio´ n, Espan˜ a. Funding for open access charge: Instituto de Salud Carlos III, Ministry of Science and Technology, Spain.Peer reviewe

    Strategies to overcome physician shortages in northern Ontario: A study of policy implementation over 35 years

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Shortages and maldistibution of physicians in northern Ontario, Canada, have been a long-standing issue. This study seeks to document, in a chronological manner, the introduction of programmes intended to help solve the problem by the provincial government over a 35-year period and to examine several aspects of policy implementation, using these programmes as a case study.</p> <p>Methods</p> <p>A programme analysis approach was adopted to examine each of a broad range of programmes to determine its year of introduction, strategic category, complexity, time frame, and expected outcome. A chronology of programme initiation was constructed, on the basis of which an analysis was done to examine changes in strategies used by the provincial government from 1969 to 2004.</p> <p>Results</p> <p>Many programmes were introduced during the study period, which could be grouped into nine strategic categories. The range of policy instruments used became broader in later years. But conspicuous by their absence were programmes of a directive nature. Programmes introduced in more recent years tended to be more complex and were more likely to have a longer time perspective and pay more attention to physician retention. The study also discusses the choice of policy instruments and use of multiple strategies.</p> <p>Conclusion</p> <p>The findings suggest that an examination of a policy is incomplete if implementation has not been taken into consideration. The study has revealed a process of trial-and-error experimentation and an accumulation of past experience. The study sheds light on the intricate relationships between policy, policy implementation and use of policy instruments and programmes.</p

    Increased Circulating Endothelial Microparticles and Carotid Atherosclerosis in Obstructive Sleep Apnea

    Get PDF
    Background and Purpose Endothelial impairment is a linking mechanism between obstructive sleep apnea (USA) and cardiovascular diseases Profiles of endothelial micropanicles (EMPs) and endothelial progenitor cells (EPCs) reflect the degree of endothelial impairment The aims of this study were to measure the levels of EMI`s and progenitor cells in USA, determine the correlations between these factors and USA severity and the deuce of atherosclerosis, and document any changes in these factors after therapy Methods Subjects with (n=82) and without (n=22) OSA were recruited prospectively We measured the number of colony-forming units (CM) in cell cultuie as the endothelial progenitor cell index, and the number of EMPs using flow cytometry with CD31 [platelet endothelial cell adhesion molecule (PECAM)], CD42 (platelet glycoprotem), annexm V, and CD62E (E-selectin) antibodies at baseline and Act 4-6 weeks of continuous positive airway pressure (CPA P) therapy Carotid int ima-media thickness (IMT) was regarded as a marker of atherosclerosis Results The levels of PECAM(+)CD42(-) (p<0 001). PECAM(+)annexin V(+) (p<0 001), and E-selectin(+) micropamcles (p=0 001) were higher in USA subjects than in non-USA subjects The number of CRJ did not differ between the two groups OSA severity independently predicted the levels of PECAM(+)CD42(-) (p=0 02) and PECA(+)annexin V(+) (p=0 004) Carotid IMT was correlated with USA severity (p<0 001), PECAM(+)CD42: (p=0 03), and PECAM(+)annexin (p=0 01) Neither USA severity nor carotid IMT was correlated with either the number of CFI) or E-selectin(+) CPAP therapy decreased the occurrence of E-selecte (p<0 001) in 21 of the USA subjects, but had no effect on the other micioparticles of the number CFU Conclusions USA led to the overproduction of EMI`s, which moderately correlated with USA seventy and the degree of atherosclerosis, and partly responded to therapy The endothelial impairment might contribute to future cardiovascular events J Clin Neurol 2010;6`89-98This research was supported by the Stem Cell Research Center of the 21st Century Frontier Research Program funded by the Ministry of Science and Technology, Republic of Korea (#SC4120).de Lima AMJ, 2010, RESPIRATION, V79, P370, DOI 10.1159/000227800Jung KH, 2009, ANN NEUROL, V66, P191, DOI 10.1002/ana.21681Ayers L, 2009, EUR RESPIR J, V33, P574, DOI 10.1183/09031936.00107408Akinnusi ME, 2009, AM J RESP CRIT CARE, V179, P328Christou K, 2009, SLEEP MED, V10, P87, DOI 10.1016/j.sleep.2007.10.011Barcelo A, 2008, THORAX, V63, P946, DOI 10.1136/thx.2007.093740Dorkova Z, 2008, CHEST, V134, P686, DOI 10.1378/chest.08-0556Robinson GV, 2008, THORAX, V63, P855, DOI 10.1136/thx.2007.088096Somers VK, 2008, CIRCULATION, V118, P1080, DOI 10.1161/CIRCULATIONAHA.107.189375Hirschi KK, 2008, ARTERIOSCL THROM VAS, V28, P1584, DOI 10.1161/ATVBAHA.107.155960Daniel L, 2008, NEPHROL DIAL TRANSPL, V23, P2129, DOI 10.1093/ndt/gfn029Martin K, 2008, LUNG, V186, P145, DOI 10.1007/s00408-008-9073-yAmabile N, 2008, AM J RESP CRIT CARE, V177, P1268, DOI 10.1164/rccm.200710-1458OCHeiss C, 2008, J AM COLL CARDIOL, V51, P1760, DOI 10.1016/j.jacc.2008.01.040Chu K, 2008, STROKE, V39, P1441, DOI 10.1161/STROKEAHA.107.499236Jelic S, 2008, CIRCULATION, V117, P2270, DOI 10.1161/CIRCULATIONAHA.107.741512Lee ST, 2008, NEUROLOGY, V70, P1510Bakouboula B, 2008, AM J RESP CRIT CARE, V177, P536, DOI 10.1164/rccm.200706-840OCLopez-Jimenez F, 2008, CHEST, V133, P793, DOI 10.1378/chest.07-0800de la Pena M, 2008, RESPIRATION, V76, P28, DOI 10.1159/000109643WON CHJ, 2008, P AM THORAC SOC, V5, P193Kloner RA, 2007, CIRCULATION, V116, P1306, DOI 10.1161/CIRCULATIONAHA.106.678375El Solh AA, 2007, AM J RESP CRIT CARE, V175, P1186, DOI 10.1164/rccm.200611-1598OCIBER C, 2007, AASM MANUAL SCORINGMONTSERRAT JM, 2007, AM J RESP CRIT CARE, V176, P6Pirro M, 2006, ARTERIOSCL THROM VAS, V26, P2530, DOI 10.1161/01.ATV.0000243941.72375.15Ryan S, 2006, AM J RESP CRIT CARE, V174, P824, DOI 10.1164/rccm.200601-066OCBoulanger CM, 2006, HYPERTENSION, V48, P180, DOI 10.1161/01.HYP.0000231507.00962.b5Arteaga RB, 2006, AM J CARDIOL, V98, P70, DOI 10.1016/j.amjcard.2006.01.054Robinson GV, 2006, EUR RESPIR J, V27, P1229, DOI 10.1183/09031936.06.00062805Werner N, 2005, NEW ENGL J MED, V353, P999Mezentsev A, 2005, AM J PHYSIOL-HEART C, V289, pH1106, DOI 10.1152/ajpheart.00265.2005Minoguchi K, 2005, AM J RESP CRIT CARE, V172, P625, DOI 10.1164/rccm.200412-1652OCMassa M, 2005, BLOOD, V105, P199, DOI 10.1182/blood-2004-05-1831Kim J, 2004, AM J RESP CRIT CARE, V170, P1108, DOI 10.1164/rccm.200404-519OCJy W, 2004, J THROMB HAEMOST, V2, P1842Tramontano AF, 2004, BIOCHEM BIOPH RES CO, V320, P34, DOI 10.1016/j.bbrc.2004.05.127Ip MSM, 2004, AM J RESP CRIT CARE, V169, P348, DOI 10.1164/rccm.200306.767OCBarba C, 2004, LANCET, V363, P157Bernal-Mizrachi L, 2003, AM HEART J, V145, P962, DOI 10.1016/S0002-8703(03)00103-0Jimenez JJ, 2003, THROMB RES, V109, P175, DOI 10.1016/S0049-3848(03)00064-1Hill JM, 2003, NEW ENGL J MED, V348, P593Preston RA, 2003, HYPERTENSION, V41, P211, DOI 10.1161/01.HYP.0000049760.15764.2DSabatier F, 2002, DIABETES, V51, P2840, DOI 10.2337/diabetes.51.9.2840El-Solh AA, 2002, CHEST, V121, P1541Boulanger CM, 2001, CIRCULATION, V104, P2649Barbe F, 2001, ANN INTERN MED, V134, P1015Chin K, 2000, AM J MED, V109, P562Lusis AJ, 2000, NATURE, V407, P233Ohga E, 1999, J APPL PHYSIOL, V87, P10YOUNG T, 1993, NEW ENGL J MED, V328, P1230JOHNS MW, 1991, SLEEP, V14, P540

    Robo2-Slit1 dependent cell-cell interactions mediate assembly of the trigeminal ganglion

    Get PDF
    Vertebrate cranial sensory ganglia, responsible for sensation of touch, taste and pain in the face and viscera, are composed of both ectodermal placode and neural crest cells. The cellular and molecular interactions allowing generation of complex ganglia remain unknown. Here, we show that proper formation of the trigeminal ganglion, the largest of the cranial ganglia, relies on reciprocal interactions between placode and neural crest cells in chick, as removal of either population resulted in severe defects. We demonstrate that ingressing placode cells express the Robo2 receptor and early migrating cranial neural crest cells express its cognate ligand Slit1. Perturbation of this receptor-ligand interaction by blocking Robo2 function or depleting either Robo2 or Slit1 using RNA interference disrupted proper ganglion formation. The resultant disorganization mimics the effects of neural crest ablation. Thus, our data reveal a novel and essential role for Robo2-Slit1 signaling in mediating neural crest–placode interactions during trigeminal gangliogenesis
    corecore