648 research outputs found
Optical spectrum of proflavine and its ions
Motivated by possible astrophysical and biological applications we calculate
visible and near UV spectral lines of proflavine (C13H11N3,
3,6-diaminoacridine) in vacuum, as well as its anion, cation, and dication. The
pseudopotential density functional and time-dependent density functional
methods are used. We find a good agreement in spectral line positions
calculated by two real-time propagation methods and the Lanczos chain method.
Spectra of proflavine and its ions show characteristic UV lines which are good
candidates for a detection of these molecules in interstellar space and various
biological processes
Coming to Terms with the Concept of Moving Species Threatened by Climate Change – A Systematic Review of the Terminology and Definitions.
Awareness of prostate cancer among patients and the general public: results of an international survey
The objective of this study was to assess the level of awareness of prostate cancer (PCa) among the general public and PCa patients in Europe and North America. A survey was undertaken across four European countries (UK, Germany, Italy and Spain), and across the United States and Canada in late 2007. In total, 1008 men with PCa and their partners (the ‘prostate sample'), and 911 men without PCa and their partners (the ‘well sample') participated in the survey, all aged ⩾50 years. Interviews were conducted through telephone, pen and paper, and online. Many people surveyed (53%) thought that breast cancer is more common than PCa. Moreover, 1 in 10 people from the well sample (10%) thought that PCa affects both men and women. When the prostate sample was asked about their perceived level of risk of PCa before diagnosis, 50% believed that they/their husband or partner were previously at low or very low risk, before they were diagnosed. Awareness of the major risk factors for PCa (age and family history) was generally good, but respondents were less clear about the role of other potential factors, such as smoking and drinking alcohol. This international survey, thought to be largest of its type, shows that although patient and public awareness of PCa is generally satisfactory, there is still a considerable lack of clarity about PCa risk factors, and a danger for people to underestimate their own/their partner's perceived risk for PCa. Programmes to responsibly educate and inform men and their partners about risk factors, prevalence and screening tools for PCa are required
Path Integrals for Potential Scattering
Two path integral representations for the -matrix in nonrelativistic
potential scattering are derived and proved to produce the complete Born series
when expanded to all orders. They are obtained with the help of "phantom"
degrees of freedom which take away explicit phases that diverge for asymptotic
times. In addition, energy conservation is enforced by imposing a
Faddeev-Popov-like constraint in the velocity path integral. These expressions
may be useful for attempts to evaluate the path integral in real time and for
alternative multiple scattering expansions. Standard and novel eikonal-type
high-energy approximations and systematic expansions immediately follow.Comment: 31 pages, 3 figures, Latex;v2: typo in eq. (4.6) corrected,
references updated;v3: misprints corrected, small changes in text following
referee comments and PR style conventions (except some idiosyncrasies),
matches published version + typo correction in eq. (88
Pathways to diagnosis for Black men and White men found to have prostate cancer: the PROCESS cohort study
Black men in England have three times the age-adjusted incidence of diagnosed prostate cancer as compared with their White counterparts. This population-based retrospective cohort study is the first UK-based investigation of whether access to diagnostic services underlies the association between race and prostate cancer. Prostate cancer was ascertained using multiple sources including hospital records. Race and factors that may influence prostate cancer diagnosis were assessed by questionnaire and hospital records review. We found that Black men were diagnosed an average of 5.1 years younger as compared with White men (P<0.001). Men of both races were comparable in their knowledge of prostate cancer, in the delays reported before presentation, and in their experience of co-morbidity and symptoms. Black men were more likely to be referred for diagnostic investigation by a hospital department (P=0.013), although general practitioners referred the large majority of men. Prostate-specific antigen levels were comparable at diagnosis, although Black men had higher levels when compared with same-age White men (P<0.001). In conclusion, we found no evidence of Black men having poorer access to diagnostic services. Differences in the run-up to diagnosis are modest and seem insufficient to explain the higher rate of prostate cancer diagnosis in Black men
Extracorporeal Blood Purification in the Intensive Care Units
peer reviewedMortality remains high in intensive care patients with renal failure requiring extra corporeal blood purification. This article reviews the recent data that have led to the improvement of the care for such patients. We will discuss the criteria to determine the choice of the technique (intermittent or continuous), of the membrane, of the prescribing dose, and the type of anticoagulation and when to initiate such a treatment
Probing the urea dependence of residual structure in denatured human α-lactalbumin
Backbone 15N relaxation parameters and 15N–1HN residual dipolar couplings (RDCs) have been measured for a variant of human α-lactalbumin (α-LA) in 4, 6, 8 and 10 M urea. In the α-LA variant, the eight cysteine residues in the protein have been replaced by alanines (all-Ala α-LA). This protein is a partially folded molten globule at pH 2 and has been shown previously to unfold in a stepwise non-cooperative manner on the addition of urea. 15N R2 values in some regions of all-Ala α-LA show significant exchange broadening which is reduced as the urea concentration is increased. Experimental RDC data are compared with RDCs predicted from a statistical coil model and with bulkiness, average area buried upon folding and hydrophobicity profiles in order to identify regions of non-random structure. Residues in the regions corresponding to the B, D and C-terminal 310 helices in native α-LA show R2 values and RDC data consistent with some non-random structural propensities even at high urea concentrations. Indeed, for residues 101–106 the residual structure persists in 10 M urea and the RDC data suggest that this might include the formation of a turn-like structure. The data presented here allow a detailed characterization of the non-cooperative unfolding of all-Ala α-LA at higher concentrations of denaturant and complement previous studies which focused on structural features of the molten globule which is populated at lower concentrations of denaturant
Patient selection for left ventricular assist devices
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102692/1/ejhfhfq006.pd
A comparative analysis of predictive models of morbidity in intensive care unit after cardiac surgery – Part I: model planning
<p>Abstract</p> <p>Background</p> <p>Different methods have recently been proposed for predicting morbidity in intensive care units (ICU). The aim of the present study was to critically review a number of approaches for developing models capable of estimating the probability of morbidity in ICU after heart surgery. The study is divided into two parts. In this first part, popular models used to estimate the probability of class membership are grouped into distinct categories according to their underlying mathematical principles. Modelling techniques and intrinsic strengths and weaknesses of each model are analysed and discussed from a theoretical point of view, in consideration of clinical applications.</p> <p>Methods</p> <p>Models based on Bayes rule, <it>k-</it>nearest neighbour algorithm, logistic regression, scoring systems and artificial neural networks are investigated. Key issues for model design are described. The mathematical treatment of some aspects of model structure is also included for readers interested in developing models, though a full understanding of mathematical relationships is not necessary if the reader is only interested in perceiving the practical meaning of model assumptions, weaknesses and strengths from a user point of view.</p> <p>Results</p> <p>Scoring systems are very attractive due to their simplicity of use, although this may undermine their predictive capacity. Logistic regression models are trustworthy tools, although they suffer from the principal limitations of most regression procedures. Bayesian models seem to be a good compromise between complexity and predictive performance, but model recalibration is generally necessary. <it>k</it>-nearest neighbour may be a valid non parametric technique, though computational cost and the need for large data storage are major weaknesses of this approach. Artificial neural networks have intrinsic advantages with respect to common statistical models, though the training process may be problematical.</p> <p>Conclusion</p> <p>Knowledge of model assumptions and the theoretical strengths and weaknesses of different approaches are fundamental for designing models for estimating the probability of morbidity after heart surgery. However, a rational choice also requires evaluation and comparison of actual performances of locally-developed competitive models in the clinical scenario to obtain satisfactory agreement between local needs and model response. In the second part of this study the above predictive models will therefore be tested on real data acquired in a specialized ICU.</p
In Search of Cellular Immunophenotypes in the Blood of Children with Autism
Autism is a neurodevelopmental disorder characterized by impairments in social behavior, communication difficulties and the occurrence of repetitive or stereotyped behaviors. There has been substantial evidence for dysregulation of the immune system in autism.We evaluated differences in the number and phenotype of circulating blood cells in young children with autism (n = 70) compared with age-matched controls (n = 35). Children with a confirmed diagnosis of autism (4-6 years of age) were further subdivided into low (IQ<68, n = 35) or high functioning (IQ ≥ 68, n = 35) groups. Age- and gender-matched typically developing children constituted the control group. Six hundred and forty four primary and secondary variables, including cell counts and the abundance of cell surface antigens, were assessed using microvolume laser scanning cytometry.There were multiple differences in immune cell populations between the autism and control groups. The absolute number of B cells per volume of blood was over 20% higher for children with autism and the absolute number of NK cells was about 40% higher. Neither of these variables showed significant difference between the low and high functioning autism groups. While the absolute number of T cells was not different across groups, a number of cellular activation markers, including HLA-DR and CD26 on T cells, and CD38 on B cells, were significantly higher in the autism group compared to controls.These results support previous findings that immune dysfunction may occur in some children with autism. Further evaluation of the nature of the dysfunction and how it may play a role in the etiology of autism or in facets of autism neuropathology and/or behavior are needed
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