702 research outputs found
Bio-R/evolution in historiographic perspective: some reflections on the history and epistemology of biomolecular science
Does the molecular vision of life signify a unique revolution in biology or a more general evolution of the life sciences in the twentieth century? This paper visits this âbig questionâ by reflecting on a series of major debates in the historiography of molecular biology, especially those regarding its origins and the periodization of its development. For instance, while some have suggested that the discipline emerged in the 1930s, others have argued for its birth in the post-WWII era. Above all, the impact of the Rockefeller Foundation and the physical sciences on the formation of molecular biology remains a central topic of discussion among historians of biology. Unlike earlier historians of biomolecular science, recent scholars have also started to pay closer attention to the laboratory and material cultures that had conditioned its historical shaping. This paper argues that, ultimately, these debates all rest upon one fundamental historiographical problem: the absence of a unifying understanding of âmolecular biologyâ among historians (and practitioners) of biological science. This heterogeneous conceptualization of âmolecular biologyâ, however, should be viewed as valuable because it allows for multiple approaches to resolving the ârevolution versus evolutionâ debate that together enrich our interpretation of the twentieth-century biomolecular vision of life
Urothelial Inverted Papilloma of the Lower Urinary TractâA Benign Lesion or a Precursor of Malignancy?
ObjectiveWe investigated the clinical characteristics and follow-up results of patients with a lower urinary tract inverted papilloma (IP) in our hospital, with the intention of clarifying whether certain groups require more aggressive surveillance.Materials and MethodsWe conducted a retrospective study of lower urinary tract IP, using the pathology database of Taipei Veterans General Hospital, from September 1992 to February 2008. In total, 67 patients were enrolled. Patients' clinical characteristics, symptoms, tumor locations, and follow-up data were analyzed.ResultsAmong the 67 patients diagnosed with IP, 59 were male and eight were female, with a mean age of 67.9 ± 12.4 years. Gross hematuria and lower-urinary-tract symptoms were the most common symptoms. All of the patients received transurethral resection as initial treatment. Thirty-eight of these patients were monitored for a median of 21 months (range: 3â168 months). Seven patients had synchronous urothelial malignancies, and one had recurrent IP during follow-up. No patient had subsequent urothelial carcinoma or IP recurrence without a synchronous or previous urothelial malignancy during follow-up.ConclusionThere is a low incidence of developing a subsequent malignancy with a simple IP lesion during follow-up. Rigorous surveillance may be unnecessary in IP patients without a synchronous or previous urothelial malignancy
Work stress and cancer researchers : an exploration of the challenges, experiences and training needs of UK cancer researchers.
Work stress is a significant issue for many UK healthcare professionals, in particular those working in the field of oncology. However, there have been very few attempts to explore the challenges, experiences or training needs of researchers working in cancer research. In doing so, we will be better positioned to support and develop these researchers.
18 UK oncology researchers from a variety of backgrounds took part in a semi-structured interview. Interviews were transcribed and analysed using thematic analysis.
The analysis identified two overarching themes: logistical research issues (workload, accessing/ recruiting participants, finances) and sensitive research issues (emotional demands, professional boundaries, sensitivity around recruitment). One cross-cutting theme, supportive strategies (support and training, coping mechanisms), was seen to influence both logistical and sensitive research issues. While further research is needed to fully understand the causes and impact of work stress on cancer researchers, three specific issues were highlighted: emotional demands are relevant to quantitative and mixed methods researchers as well as those engaged in qualitative research; the researchersâ background (experience; clinical/non-clinical) was influential and an exploration of effective coping strategies is required; and there is a clear need for adequate support systems and training to be available, particularly for early career researchers.</p
Evolutionary Tracks of Trapped, Accreting Protoplanets: the Origin of the Observed Mass-Period Relation
The large number of observed exoplanets ( 700) provides important
constraints on their origin as deduced from the mass-period diagram of planets.
The most surprising features in the diagram are 1) the (apparent) pile up of
gas giants at a period of days ( AU) and 2) the so-called
mass-period relation which indicates that planetary mass is an increasing
function of orbital period. We construct the evolutionary tracks of growing
planets at planet traps in evolving protoplanetary disks and show that they
provide a good physical understanding of how these observational properties
arise. The fundamental feature of our model is that inhomogeneities in
protoplanetary disks give rise to multiple (up to 3) trapping sites for rapid
(type I) planetary migration of planetary cores. The viscous evolution of disks
results in the slow radial movement of the traps and their cores from large to
small orbital periods. In our model, the slow inward motion of planet traps is
coupled with the standard core accretion scenario for planetary growth. As
planets grow, type II migration takes over. Planet growth and radial movement
are ultimately stalled by the dispersal of gas disks via photoevaporation. Our
model makes a number of important predictions: that distinct sub-populations of
planets that reflect the properties of planet traps where they have grown
result in the mass-period relation; that the presence of these sub-populations
naturally explains a pile-up of planets at AU; and that evolutionary
tracks from the ice line do put planets at short periods and fill an earlier
claimed "planet desert" - sparse population of planets in the mass-semi-major
axis diagram.Comment: 20 pages, 11 figures, 9 tables; accepted for publication in ApJ. No
change in our conclusions while more discussion is added for supporting the
importance of planet trap
Introduction: transnational lesbian cultures
This Introduction sets out the aims and scope of this special journal issue. The issue examines the transnational shape and shaping of lesbian lives and cultures in and across China, India, the United Kingdom, and the United States. It uses the expression âtransnational lesbian culturesâ to suggest that despite sometimes radically different sociopolitical and cultural contexts, the lived experiences of same-sex desire and their emotional attachments create particular affinities between women who love women, affinities that reach across the distinct cultural and social contexts that shape them. The articles brought together explore lesbian subcultures, film, graphic novels, music, and online intimacies. They show that as a cultural and political signifier and as an analytical tool, lesbian troubles and complicates contemporary sexual politics, not least by revealing some of the gendered structures that shape debates about sexuality in a range of critical, cultural and political contexts. While the individual pieces cover a wide range of issues and concernsâwhich are often highly specific to the historical, cultural, and political contexts they discussâtogether they tell a story about contemporary transnational lesbian culture: one that is marked by intricate links between norms and their effects and shaped by the efforts to resist denial, discrimination, and sometimes even active persecution
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Attenuation of RNA polymerase II pausing mitigates BRCA1-associated R-loop accumulation and tumorigenesis.
Most BRCA1-associated breast tumours are basal-like yet originate from luminal progenitors. BRCA1 is best known for its functions in double-strand break repair and resolution of DNA replication stress. However, it is unclear whether loss of these ubiquitously important functions fully explains the cell lineage-specific tumorigenesis. In vitro studies implicate BRCA1 in elimination of R-loops, DNA-RNA hybrid structures involved in transcription and genetic instability. Here we show that R-loops accumulate preferentially in breast luminal epithelial cells, not in basal epithelial or stromal cells, of BRCA1 mutation carriers. Furthermore, R-loops are enriched at the 5' end of those genes with promoter-proximal RNA polymerase II (Pol II) pausing. Genetic ablation of Cobra1, which encodes a Pol II-pausing and BRCA1-binding protein, ameliorates R-loop accumulation and reduces tumorigenesis in Brca1-knockout mouse mammary epithelium. Our studies show that Pol II pausing is an important contributor to BRCA1-associated R-loop accumulation and breast cancer development
Observation of a Smoothly Tunable Dirac Point in
State-of-the-art topological devices require the use topological surface
states to drive electronic transport. In this study, we examine a tunable
topological system, , for a range of 'x' values
from 0 to 1, using a combination of Fourier Transform Scanning Tunneling
Spectroscopy (FT-STS) and Angle-Resolved Photoemission Spectroscopy (ARPES).
Our results show that the Dirac point shifts linearly with 'x', crossing the
Fermi energy near x = 0.7. This novel observation of a smoothly tunable,
isolated Dirac point crossing through the topological transport regime and
having strong linear dependence with substitution can be critical for future
topological spintronics applications.Comment: 18 Pages, 9 Figures, including Appendi
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