Dynamic Vessel Analysis using surface-mount device LEDs as light source

Purpose : In human retinal blood flow research dynamic vessel analysis (DVA) with the Retinal Vessel Analyzer (Imedos Systems UG) is the Gold standard to measure alterations in vessel diameter. However, vessel contrast is often reduced due to stray light caused by illumination of lash, lid, or opaque lens such as cataract lens. For reasons of spatial adaptation, we developed and validated a novel 24-fold segmented LED light source for fundus cameras based on surface-mount technology. Methods : We studied 16 young volunteers (7f, 8m, 24.7±1.5 years) all free of ocular or systemic disease. To compare the new setup with the Gold standard the relative maximum vaso-dilation value was determined. We measured four primary vessels: one superior temporal artery and vein (STa/STv), one inferior temporal artery and vein (ITa/ITv), as well. The surface-mount device LED-based light source was connected to a mydriatic fundus camera (Visucam, Carl Zeiss Meditec AG). We followed the DVA standard protocol. The beam geometry was annular (all segments on). Each volunteer was measured two times. One measurement with the Gold standard and one with the new setup, in a random order. A resting period of approximately 10 minutes was adhered between the DVA measurements to avoid suppression of retinal vessel reactions in consecutive experiments. Comparison of the two setups were demonstrated and analyzed using the Bland-Altmann method. To value the differences among the group means we performed a paired t-test. All four data sets (n=16, each) were normal distributed (Shapiro-Wilk). Results : The comparison analysis according to Bland-Altmann, with no outliers, resulted in the following mean differences (MD) and Limits of Agreement (LoA) with n=16 for every type of vessel (Gold standard vs. new setup). STa: MD=-0.28%, LoA=-3.28%/+2.71. ITa: MD=-0.09%, LoA=-3.01%/+2.84. STv: MD=-0.44%, LoA=-2.63%/+3.52. ITv: MD=-0.54%, LoA=-2.55%/+1.02. The t-test p-values were 0.473 (STa), 0.818 (ITa), 0.276 (STv), and 0.050 (ITv). p≥0.05 means no significant difference. Conclusions : We successfully performed a new approach of Dynamic Vessel Analysis using a miniaturized surface-mount device LED-based light source. Statistically, there are no significant differences in the maximum dilation value of the new setup compared to the Gold standard. The new setup can be used for dynamic vessel analysis in humans as well

Retinal vessel diameter variations and their correlation to arterial blood pressure

Purpose : The risk for cardiovascular diseases can be evaluated by the measuring of the retinal blood vessel diameters. Temporal variations in vessel diameter lead to uncertainties. Mayer waves are cyclic variations in cardiovascular system, which can be seen in arterial blood pressure. A link to retinal vessel diameters is known in general but temporal dependencies are not described yet. We investigated the similarity of these variations and determined the temporal dependencies in a multimodal measurement study. Methods : In a study in accordance with the Declaration of Helsinki we performed measurements on 15 young and healthy subjects. Within a time period of 90 minutes, six repeated measurements with a duration of six minutes each were conducted. We did a simultaneous measurement of retinal vessel diameters (Dynamic Vessel Analyzer, IMEDOS Systems UG, Jena, Germany) and non-invasive continuous arterial blood pressure (Finometer Pro, Finapres Medical Systems B.V., Enschede, The Netherlands). The sum of the diameters was calculated for both arteries and veins. We extracted waves in Very Low Frequency range (VLF, 0.02–0.07Hz) and Low Frequency range (LF, 0.07–0.15Hz) by filtering and determined temporal dependencies between both modalities using cross correlation. We extracted the lags of best signal correlation and calculated statistical parameters. Results : Cross correlation analysis showed clear dependencies in most of the 90 datasets. The strongest correlations were in VLF: minima of arteries: median -3.68 s, Interquartile range (IQR) 3.57, minima of veins: median -5.89 s, IQR 3.85 and in LF: minima of arteries: median -3.95 s, IQR 3.29, maxima of veins: median -0.10 s, IQR 0.98. Negative time lags mean retinal vessel diameter follows blood pressure signal. Distribution of the time shifts in LF was much closer than in VLF. Most of the outliers were shifted by one period. Correlation coefficients ranged up to 0.82 for frequencies in VLF and up to 0.94 in LF, randomly shifted outliers had lower correlation coefficients up to 0.4. Most outliers were concentrated on a few subjects. Conclusions : Our study showed clear dependencies between variations in retinal vessel diameter and arterial blood pressure. The best correlation could be seen in VLF on minima of arteries and veins and in LF on minima of arteries and maxima of veins, yielding the smallest variation in time shift and the smallest number of outliers

Feasibility, psychological outcomes and practical use of a stress-preventive leadership intervention in the workplace hospital:The results of a mixed-method phase-II study

OBJECTIVES: Hospitals are psychologically demanding workplaces with a need for context-specific stress-preventive leadership interventions. A stress-preventive interprofessional leadership intervention for middle management has been developed. This phase-II study investigates its feasibility and outcomes, including work-related stress, well-being and transformational leadership. DESIGN: This is a mixed-methods study with three measure points (T0: baseline, T1: after the last training session, T2: 3-month follow-up). Additionally, focus groups were conducted to assess participants’ change in everyday work. SETTING: A tertiary hospital in Germany. PARTICIPANTS: N=93 leaders of different professions. INTERVENTION: An interactive group setting intervention divided in five separate sessions ((1) self-care as a leader, (2) leadership attitudes and behaviour, (3) motives, needs and stressors of employees, (4) strengthen the resource ‘team’, (5) reflection and focus groups). The intervention was conducted between June 2018 and March 2020 in k=5 runs of the intervention. OUTCOME MEASURES: Feasibility and acceptance were measured with a self-developed intervention specific questionnaire. Psychological outcomes were assessed with the following scales: work-related strain with the Irritation Scale, well-being with the WHO-5 Well-being Index and transformational leadership with the Questionnaire of Integrative Leadership. RESULTS: After the intervention at T2, over 90% of participants reported that they would recommend the intervention to another coworker (92.1%, n=59) and all participants (n=64) were satisfied with the intervention and rated the intervention as practical relevant for their everyday work. Participants’ self-rated cognitive irritation was reduced, whereas their well-being and transformational leadership behaviour were improved over time. Focus group discussions revealed that participants implemented intervention contents successfully in their everyday work. CONCLUSIONS: This intervention was feasible and showed first promising intraindividual changes in psychological outcomes. Participants confirmed its practical relevance. As a next step, the intervention will be evaluated as part of a multicentre—randomised controlled trial within the project SEEGEN (SEElische GEsundheit am Arbeitsplatz KrankeNhaus)

Forschungsinformationsmanagement

Die Bedeutung von Forschungsberichterstattung für Universitäten nimmt kontinuierlich zu. So müssen Universitäten Berichtspflichten gegenüber Geldgebern und Ministerien erfüllen, Informationen zur internen Entscheidungsfindung und Steuerung bereithalten sowie Rechenschaft über ihre Geldgeber gegenüber der Öffentlichkeit ablegen. Forschungsberichterstattung ist somit von hoher strategischer Bedeutung für die Steuerungs- und Wettbewerbsfähigkeit der Universitäten sowie für die Sichtbarkeit und Transparenz ihrer Forschungsleistungen nach außen. Gleichzeitig stellen die steigenden Anforderungen an die Forschungsberichterstattung die Universitäten in Baden-Württemberg vor schwierige Aufgaben, da die benötigten Daten zu Forschungsaktivitäten oft nur verteilt und in uneinheitlicher Form in den Institutionen vorliegen. Dies führt zu einem hohen administrativen Aufwand in der Forschungsberichterstattung. Aus diesem Grund empfiehlt auch der Wissenschaftsrat den Hochschulen, ihre Forschungsberichterstattung zu professionalisieren. Dieses Papier des Think Tank Forschungsinformationsmanagement schlägt daher vor, dass sich die baden-württembergischen Universitäten zu einem Verbund zum Thema Forschungsinformationssysteme („BW.CRIS“) zusammenschließen. Ziel des Verbundes ist, Kompetenzen in diesem Bereich zu bündeln, gemeinsame Lösungen für gemeinsame Herausforderungen zu erarbeiten und im gegenseitigen Austausch von den Erfahrungen der anderen Universitäten zu lernen. Im Verbund erhalten die Landesuniversitäten zudem eine starke Stimme und können so die Landesinteressen gegenüber Softwareanbietern, der KFiD oder weiteren Akteuren auf Bundesebene erfolgreich vertreten. Ein zentraler Erfolgsfaktor für den Anschub und die nachhaltige Arbeit eines solchen Verbundes wäre seine gezielte Unterstützung auf Landesebene. Eine solche baden-württembergische Landesinitiative zum Thema Forschungsinformationssysteme würde die baden-württembergischen Universitäten in der Digitalisierung ihrer Forschungsberichterstattung erheblich voranbringen und so die strategische Steuerungsfähigkeit der Hochschulleitungen maßgeblich erhöhen

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe