102,187 research outputs found
Temperature-Dependent Chiral-Induced Spin Selectivity Effect: Experiments and Theory
No full textThe theoretical explanation for the chiral-induced spin selectivity effect, in which electrons’ passage through a chiral system depends on their spin and the handedness of the system, remains incomplete. Although most experimental work was performed at room temperature, most of the proposed theories did not include vibrations. Here, we present temperature-dependent experiments and a theoretical model that captures all observations and provides spin polarization values that are consistent with the experimental results. The model includes the vibrational contribution to the spin orbit coupling. It highlights the importance of dissipation and the relation between the effect and the optical activity. The model explains the main features related to the chiral-induced spin selectivity effect and provides a new framework for future calculations and experiments
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Carbon X-ray absorption spectra of fluoroethenes and acetone: A study at the coupled cluster, density functional, and static-exchange levels of theory
No full textNear carbon K-edge X-ray absorption fine structure spectra of a series of fluorine-substituted ethenes
and acetone have been studied using coupled cluster and density functional theory (DFT) polarization
propagator methods, as well as the static-exchange (STEX) approach. With the complex polarization
propagator (CPP) implemented in coupled cluster theory, relaxation effects following the
excitation of core electrons are accounted for in terms of electron correlation, enabling a systematic
convergence of these effects with respect to electron excitations in the cluster operator. Coupled
cluster results have been used as benchmarks for the assessment of propagator methods in DFT as
well as the state-specific static-exchange approach. Calculations on ethene and 1,1-difluoroethene
illustrate the possibility of using nonrelativistic coupled cluster singles and doubles (CCSD) with
additional effects of electron correlation and relativity added as scalar shifts in energetics. It has
been demonstrated that CPP spectra obtained with coupled cluster singles and approximate doubles
(CC2), CCSD, and DFT (with a Coulomb attenuated exchange-correlation functional) yield excellent
predictions of chemical shifts for vinylfluoride, 1,1-difluoroethene, trifluoroethene, as well as good
spectral features for acetone in the case of CCSD and DFT. Following this, CPP-DFT is considered to
be a viable option for the calculation of X-ray absorption spectra of larger π-conjugated systems, and
CC2 is deemed applicable for chemical shifts but not for studies of fine structure features. The CCSD
method as well as the more approximate CC2 method are shown to yield spectral features relating
to π*-resonances in good agreement with experiment, not only for the aforementioned molecules
but also for ethene, cis-1,2-difluoroethene, and tetrafluoroethene. The STEX approach is shown to
underestimate π*-peak separations due to spectral compressions, a characteristic which is inherent
to this method
Coupled cluster study of near-edge x-ray absorption spectra
No full textCoupled cluster methods are considered among the most accurate tools in
electronic structure theory to obtain ground state properties and spectroscopic
properties. Nonetheless, their application to the high-energy region, specifically
to describe the core-excitation phenomena that are behind spectroscopic
techniques like XAS and XCD are very limited.
We present here an implementation of damped response theory based on an
asymmetric Lanczos algorithm within Coupled Cluster theory for the CCS, CC2
and CCSD approximations, We apply it to the simulation of the K-edge X-ray
absorption spectra of the closed-shell 10-electron systems Neon, CH4, H2O, HF
and NH3. The effect of triple excitations on the excitation energies is estimated
by means of the CCSDR(3) approximation. Results are compared with
experiment as well as results obtained with other computational methods, in
particular the Hartree-Fock STEX approach
Faktorer hos sjuksköterskan som påverkar patientens förtroende och trygghetskänsla: En intervjustudie
No full textFAKTORER HOS SJUKSKÖTERSKAN SOM PÅVERKAR PATIENTENS FÖRTROENDE OCH TRYGGHETSKÄNSLA
En intervjustudie
Caroline Fransson
Sara Persson
Fransson, C & Persson, S. Faktorer hos sjuksköterskan som påverkar patientens förtroende och trygghetskänsla. En intervjustudie. Examensarbete i omvårdnad 10 poäng. Malmö högskola: Hälsa och Samhälle, Utbildningsområde omvårdnad, 2005.
Syftet: Syftet med denna studie var att belysa vilka faktorer (inre och yttre) hos sjuksköterskan som påverkar patientens förtroende och trygghetskänsla i omvårdnaden. Frågeställningarna lyder: Hur kan sjuksköterskan göra för att få patientens förtroende och känsla av trygghet? På vilket sätt påverkas förtroendet och trygghetskänslan utav sjuksköterskans bemötande? Har sjuksköterskans personliga utseende och stil någon betydelse för patienten? I denna undersökning menar författarna att yttre faktorer är t ex smycken, smink, frisyr och tatueringar. De inre faktorerna syftar mer på sjuksköterskans bemötande mot patienten. Metod: Studien var en kvalitativ empirisk intervjustudie som utfördes på sex inneliggande patienter över 60 år. Materialet bearbetades och analyserades genom kategorisering. Resultat: Resultatet av studien visar bland annat att patientens förtroende och trygghetskänsla påverkas till stor del utav sjuksköterskans inre respektive yttre faktorer. Det som påverkar patientens förtroende och trygghetskänsla är främst de inre faktorerna så som bemötandet.
Nyckelord: bemötande, förtroende, personlig stil, sjuksköterska, trygghetFACTORS IN NURSES THAT INFLUENCE THE PATIENTS TRUST AND FEELING OF SECURITY
An interview study
Caroline Fransson
Sara Persson
Fransson, C & Persson, S. Factors in nurses that influence the patients trust and feeling of security. An interview study. Degree project, 10 Credit Points. Nursing Program, Malmö University: Health and Society, Department of Nursing, 2005.
Purpose: The purpose of this study was to shed light on what factors (internal and external) the nurse has that influence the patients trust and feeling of security while in their care. The Posed Questions: What can the nurse do to gain the patients trust and feeling of security? In what ways are trust and feeling of security affected by the nurse’s personal approach? Does the nurse’s personal appearance and style have any significant influence on the patient? In this study, the authors exemplify external factors as jewellery, make-up, hair style and tattoos. The internal factors are referring to the nurse’s behaviour towards the patient. Method: The study is an empirical qualitative interview study that was conducted with six inpatients above the age of 60. The material was processed and analysed through categorisation. Results: The findings showed that the patients trust and feelings of security are largely of both by the nurse’s internal and external factors. The main influences on the patient’s trust and feeling of security are the internal factors, such as personal approach by the nurse.
Keywords: feeling of security, nurse, personal approach, personal style, trus
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Job strain in relation to body mass index: pooled analysis of 160,000 adults from 13 cohort studies.
No full textBackground. Evidence of an association between job strain and obesity is mixed, mostly limited to small-scale studies, and does not distinguish between categories of underweight or obesity sub-classes. Objectives. To examine the association between job strain and body mass index (BMI) in a large adult population. Methods. We performed a pooled cross-sectional analysis based on individual-level data from 13 European studies resulting in a total of 161,746 participants (49% men, mean age 43.7 years). Longitudinal analysis with a median follow-up of 4 years was possible in 4 cohort studies (N=42,222). Results. Of the participants, 86,429 were normal weight (BMI 18.5 - 24.9 kg/m2), 2149 underweight (BMI 35 kg/m2) obese. In all, 27,010 (17%) participants reported job strain. In cross-sectional analyses, we found increased odds of job strain among underweight (odds ratio 1.12, 95% confidence interval 1.00 to 1.25), obese class I (1.07, 95% confidence interval 1.02 to 1.12) and classes II-III participants (1.14, 95% confidence interval 1.01 to 1.28) as compared with normalweight participants. In longitudinal analysis, both weight gain and weight loss were related to the onset of job strain during follow-up. Conclusions. In an analysis of European data, we found both weight gain and weight loss to be associated with the onset of job strain, a finding which is consistent with the 'U'-shaped cross-sectional association between job strain and BMI.0Corresponding authors: Solja Nyberg Finnish Institute of Occupational Health Topeliuksenkatu 41 a A, 00250 Helsinki, Finland Email: [email protected] Tel. +358 30 474 2639 Mika Kivimaki University College London Department of Epidemiology and Public Health 1-19 Torrington Place WC1E 6BT London The UK Email: [email protected]: ar.jinfo:eu-repo/semantics/publishedAuthors list: Solja T. Nyberg,1 Katriina Heikkilä,1 Eleonor I. Fransson,2 3 Lars Alfredsson,2 Dirk De Bacquer,4 Jakob B. Bjorner,5 Sébastien Bonenfant,6 7 Marianne Borritz,8 Hermann Burr,9 Annalisa Casini,10 Els Clays,4 Nico Dragano,11 Raimund Erbel,12 Goedele A. Geuskens,13 Marcel Goldberg,6 7 Wendela E. Hooftman,13 Irene L. Houtman,13 Karl-Heinz Jöckel,11 France Kittel,10 Anders Knutsson,14 Markku Koskenvuo,15 Constanze Leineweber,16 Thorsten Lunau,11 Ida E.H. Madsen,5 Linda L. Magnusson Hanson,16 Michael G. Marmot,17 Martin L. Nielsen,18 Maria Nordin,19 Tuula Oksanen,20 21 Jaana Pentti,20 Reiner Rugulies,5 22 Johannes Siegrist,23 Sakari Suominen,24 25 Jussi Vahtera,20 24 26 Marianna Virtanen,1 Peter Westerholm,27 Hugo Westerlund,16 17 28 Marie Zins,6 7 Jane E. Ferrie,17 29 Töres Theorell,16 Andrew Steptoe,17 Mark Hamer,17 Archana Singh-Manoux,7 17 G. David Batty,17 30 and Mika Kivimäki1 17 31; for the IPD-Work Consortium 1. Finnish Institute of Occupational Health, Helsinki, Finland 2. Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden 3. School of Health Sciences, Jönköping University, Jönköping, Sweden 4. Department of Public Health, Ghent University, Ghent, Belgium 5. National Research Centre for the Working Environment, Copenhagen, Denmark 6. Versailles-Saint Quentin University, Versailles, France 7. Inserm U1018, Centre for Research in Epidemiology and Population Health, Villejuif, France 8. Department of Occupational Medicine, Bispebjerg University Hospital, Copenhagen, Denmark 9. Centre for Maritime Health and Safety, Esbjerg, Denmark 10. School of Public Health, Université Libre de Bruxelles, Brussels, Belgium 11. Institute for Medical Informatics, Biometry, and Epidemiology, University Duisburg-Essen, Essen, Germany 12. Department of Cardiology, West-German Heart Center Essen, University Duisburg-Essen, Essen, Germany 13. TNO, Hoofddorp, The Netherlands 14. Department of Health Sciences, Mid Sweden University, Sundsvall, Sweden 15. Department of Public Health, University of Helsinki, Helsinki, Finland 16. Stress Research Institute, Stockholm University, Stockholm, Sweden 17. Epidemiology and Public Health, University College London, London, UK 18. Department of Occupational and Environmental Medicine, Bispebjerg University Hospital, Copenhagen, Denmark 19. Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine, Umeå University, Umeå, Sweden 20. Finnish Institute of Occupational Health, Turku, Finland 21. Harvard School of Public Health, Department of Society, Human Development and Health, Boston, USA 22. Department of Public Health and Department of Psychology, University of Copenhagen, Copenhagen, Denmark 23. Department of Medical Sociology, University of Düsseldorf, Düsseldorf, Germany 24. Department of Public Health, University of Turku, Turku, Finland 25. Folkhälsan Research Center, Helsinki, Finland 26. Turku University Hospital, Turku, Finland 27. Occupational and Environmental Medicine, Uppsala University, Uppsala, Sweden 28. Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden 29. School of Community and Social Medicine, University of Bristol, Bristol, UK 30. Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK 31. Department of Behavioral Sciences, University of Helsinki, Helsinki, Finlan
Prevalence, extent and severity of peri-implantitis
No full textPeri-implantitis is a disorder that affects the tissues surrounding a functional implant. Peri-implantitis can lead to implant loss and impaired function. There is limited information regarding the prevalence of peri-implantitis. In addition the extent of the disease and pattern of bone loss are poorly described.
The objective of the present series of studies was to assess the prevalence of subjects exhibiting progressive bone loss at implants supporting fixed prosthesis (Study I) and to examine the clinical characteristics at implants with radiographic evidence of progressive bone loss (Study II). Furthermore, the extent, severity and pattern of peri-implantitis-associated bone loss were evaluated (Study III and Study IV).
Bone-level assessments were performed in intra-oral radiographs and the clinical conditions of the peri-implant tissues were examined. A multilevel growth curve model was used to analyze the pattern of bone loss.
It was demonstrated that 28% of subjects had one or more implants with progressive bone loss. The individuals in this group carried a significantly larger number of implants than the subjects in whom no implants with progressive loss were detected (6.0 vs. 4.8). Out of the total 3413 implants included in the study 12.4 percent demonstrated progressive bone loss (Study I).
Clinical signs of pathology were more frequent at implants with than without progressive bone loss. Smokers had larger numbers of affected implants than non-smokers and the proportion of affected implants that exhibited pus and PPD ≥ 6 mm was higher in smokers than in non-smokers. The findings of pus, recession and PPD ≥ 6mm at an implant in a smoking subject had a 69% accuracy in identifying history of progressive bone loss (Study II).
About 40% of the implants in each affected subject had peri-implantitis. The proportion of such implants varied between 30 and 52% in different jaw positions. The most common position was the lower front region. (Study III).
The average bone loss after the first year of function at the affected implants was 1.65 mm and 32% of the implants demonstrated bone loss ≥ 2 mm. The bone loss showed a non-linear pattern and the rate of bone loss increased over time (Study IV)
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