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Earlybird: A new approach to vascular assessment
No full textThe aim of the thesis was to explore and identify possible clinical applications within vascular health for a novel, high-sensitivity, ultrasound Doppler system (earlybird). The unit was developed by Professor Hans Torp, at the Department of Circulation and Imaging, NTNU. Earlybird consists of an ultrasound probe with a relatively large area, scanner, and a customized user interface. The device is designed to monitor peripheral blood flow simultaneously and continuous in a depth down to 40 mm. It allows easy placement over vessel structures of interest. The Earlybird project is part of a larger innovation and commercialization process of the underlying ultrasound technology, which includes other clinical applications.
In a proof-of-concept study (study I, paper I), it was demonstrated that earlybird correlates well with laser Doppler flowmetry and pulsed-wave Doppler to assess microcirculatory function in healthy subjects 3. This study validates earlybird’s ability to assess peripheral blood circulation.
The second study (study II, paper II and III) includes an innovational treatment-device (FlowOx™) for patients with peripheral arterial disease. A proportion of patients with intermittent claudication, are not able to participate in exercise programs due to lack of motivation or comorbidity. FlowOx™ incorporates intermittent negative pressure (INP) to increase peripheral blood circulation. In a randomized sham-controlled trial, patients with intermittent claudication were treated for 12 weeks with either 40 mmHg or 10 mmHg INP. A mean treatment effect of increase in pain-free walking distance of 50 meters was found, in favor of the 40 mmHg INP treatment group (paper II) 4. Earlybird-recordings were used to explore secondary outcomes (paper III). An immediate increase in blood flow velocities was observed during the INP treatment. Analyses of flowmotion characteristics of endothelial, sympathetic, and myogenic activity, showed a difference in change of myogenic activity between the groups after 12 weeks of treatment with INP. This finding suggests an involvement of vascular smooth muscle cells of the arterioles, and it may contribute to the understanding of the mechanism of action of INP. The ability of earlybird to monitor and assess blood flow velocities, was confirmed in patients with peripheral arterial disease.
In a pilot study (study III, congress abstract I) blood flow velocities were monitored during an endovascular procedure. Earlybird detects changes in blood flow velocities in real-time. Earlybird could be a valuable tool for periprocedural decision making, to guide the clinician in what extent to revascularize a limb 5. Further studies are needed to determine hemodynamic properties that can be associated with clinical endpoints.
Although controversial, the surveillance of volume flow rate (VFR) in arteriovenous fistulas (AVF) for hemodialysis could increase their patency. Earlybird’s ability to be a potential future tool for surveillance of VFR in AVFs was evaluated in an experimental and clinical setting (study IV, paper IV). VFR-measurements were automatically derived from earlybird’s flow velocity recordings, and was compared to duplex ultrasound, and calibrated VFR. Earlybird was found to be a feasible tool for evaluating VFR in AVFs, with a strong correlation and good agreement between the methods used 6. Further development, especially to overcome the limitations with angle dependency, may increase user-friendliness and further improve the accuracy. Earlybird could be a potential valuable tool for surveillance of VFR.
FlowOx™ is a promising device, supplementary to standard care of peripheral arterial disease. Earlybird has been demonstrated to be a feasible device to assess blood flow in healthy individuals, as well as in patients with a range of clinical challenges within the broad segment of vascular disease. Earlybird could be a future tool for clinical decision making during endovascular treatment and a future promising tool for surveillance of hemodialytic vascular access. Further technical and software development of earlybird, may increase user-friendliness and allow for a wide range of clinical applications.Norsk sammendrag
Formålet med doktorgradsarbeidet var å utforske mulige kliniske bruksområder innenfor karhelse for et nyutviklet, høy-sensitivt, ultralyd Doppler system (earlybird). Enheten er utviklet ved Institutt for sirkulasjon og bildediagnostikk, NTNU, ved professor Hans Torp. Earlybird består av ulike ultralydprober med et relativt stort areal, en skanner og et tilpasset brukergrensesnitt. Egenskapene gjør den enkel å plassere over karstrukturer av interesse. Earlybird-prosjektet er del av en større innovasjon- og kommersialiserings-prosess av den underliggende ultralyd-teknologien, som omfatter andre kliniske bruksområder.
I studie I ble earlybird sammenlignet med laser og pulset Doppler. Friske personer ble utsatt for ulike fysiologiske tester som igangsetter en vasomotorisk respons. Det ble funnet en god overenstemmelse mellom de ulike målemetodene (artikkel I). Earlybird virker til å kunne fange opp endringer i perifer blodgjennomstrømning hos friske personer.
I studie II, inkluderte man en behandlingsmetode som tar i bruk intermitterende undertrykk (FlowOx™) for å behandle pasienter med redusert blodgjennomstrømning til beina. En del av pasientene med anstrengelsesutløste gangsmerter er ikke i stand til å delta i anbefalte treningsprogram, og det er derfor interessant å vurdere ikkeinvasive behandlingsmetoder. I denne randomiserte studien var 63 pasienter tilgjengelige for vurdering etter endt oppfølgingstid. Det ble funnet at pasienter som ble behandlet i 12 uker med 40 mmHg intermitterende undertrykk hadde 50 meter gjennomsnittlig økning i smertefri gangdistanse, sammenlignet med de som ble behandlet med 10 mmHg (artikkel II). For å vurdere sekundære utfall av studien (artikkel III) ble målinger av blodstrømshastigheter, målt med earlybird, gjennomført før og etter den 12-ukers lange behandlingsperioden. Man fikk gode og pålitelige målinger av blodgjennomstrømningen. Dette viser at earlybird også kan måle endring i blodsirkulasjon hos pasienter med perifer arteriell sykdom. Målingen ble brukt til å analysere effekter på blodstrømmen, forårsaket av behandling med intermitterende undertrykk. Det ble bekreftet at intermitterende undertrykksbehandling gir en umiddelbar økning i blodstrømshastigheten. Det kan også virke som om den positive effekten sett ved behandling med FlowOx™, delvis kan forklares av økt aktivitet av glattmuskulatur i karveggen tilsvarende arteriolene.
Blodstrømshastigheter ble overvåket i sanntid med earlybird i det aktuelle beinet som gjennomgikk endovaskulær behandling (studie III, kongress abstrakt I). Først etter ballong-dilatasjon av en stent, plassert i en bekkenokklusjon, får man en økning i blodstrøm. Earlybird kan være et nyttig verktøy for peroperativ klinisk beslutningsstøtte. Imidlertid er det nødvendig med flere studier for å vurdere hvilke hemodynamiske parametere og terskelverdier som kan forutsi kliniske endepunkter.
I studie IV har man vist at earlybird kan være et fremtidig verktøy til å måle blodstrøm i arteriovenøse fistler til bruk for hemodialyse (artikkel IV). Selv om det er vist at overvåkning av arteriovenøse fistler kan redusere tromboseringsraten, diskuteres nytteverdien av slike overvåkningsregimer. Det er foreslått at analyse av blodstrømstrender kan være nyttige. Den største begrensningen til earlybird vil være at den ikke tillater vinkelkorrigering av blodstrømshastigheten. Videreutvikling av earlybird, spesielt med tanke på å gjøre den vinkeluavhengig, vil kunne øke brukervennligheten og forbedre nøyaktigheten.
Earlybird har vist seg å kunne måle og overvåke perifer blodsirkulasjon. Earlybird kan være et potensielt fremtidig verktøy for klinisk beslutningsstøtte under endovaskulære behandling og for overvåkning av arteriovenøse fistler brukt som tilgang til
hemodialyse. Ytterligere utvikling av den underliggende teknologien og programvare vil kunne øke brukervennligheten og medføre tilpasning av earlybird til et bredt spekter av kliniske bruksområder
Earlybird: A new approach to vascular assessment
No full textThe aim of the thesis was to explore and identify possible clinical applications within vascular health for a novel, high-sensitivity, ultrasound Doppler system (earlybird). The unit was developed by Professor Hans Torp, at the Department of Circulation and Imaging, NTNU. Earlybird consists of an ultrasound probe with a relatively large area, scanner, and a customized user interface. The device is designed to monitor peripheral blood flow simultaneously and continuous in a depth down to 40 mm. It allows easy placement over vessel structures of interest. The Earlybird project is part of a larger innovation and commercialization process of the underlying ultrasound technology, which includes other clinical applications.
In a proof-of-concept study (study I, paper I), it was demonstrated that earlybird correlates well with laser Doppler flowmetry and pulsed-wave Doppler to assess microcirculatory function in healthy subjects 3. This study validates earlybird’s ability to assess peripheral blood circulation.
The second study (study II, paper II and III) includes an innovational treatment-device (FlowOx™) for patients with peripheral arterial disease. A proportion of patients with intermittent claudication, are not able to participate in exercise programs due to lack of motivation or comorbidity. FlowOx™ incorporates intermittent negative pressure (INP) to increase peripheral blood circulation. In a randomized sham-controlled trial, patients with intermittent claudication were treated for 12 weeks with either 40 mmHg or 10 mmHg INP. A mean treatment effect of increase in pain-free walking distance of 50 meters was found, in favor of the 40 mmHg INP treatment group (paper II) 4. Earlybird-recordings were used to explore secondary outcomes (paper III). An immediate increase in blood flow velocities was observed during the INP treatment. Analyses of flowmotion characteristics of endothelial, sympathetic, and myogenic activity, showed a difference in change of myogenic activity between the groups after 12 weeks of treatment with INP. This finding suggests an involvement of vascular smooth muscle cells of the arterioles, and it may contribute to the understanding of the mechanism of action of INP. The ability of earlybird to monitor and assess blood flow velocities, was confirmed in patients with peripheral arterial disease.
In a pilot study (study III, congress abstract I) blood flow velocities were monitored during an endovascular procedure. Earlybird detects changes in blood flow velocities in real-time. Earlybird could be a valuable tool for periprocedural decision making, to guide the clinician in what extent to revascularize a limb 5. Further studies are needed to determine hemodynamic properties that can be associated with clinical endpoints.
Although controversial, the surveillance of volume flow rate (VFR) in arteriovenous fistulas (AVF) for hemodialysis could increase their patency. Earlybird’s ability to be a potential future tool for surveillance of VFR in AVFs was evaluated in an experimental and clinical setting (study IV, paper IV). VFR-measurements were automatically derived from earlybird’s flow velocity recordings, and was compared to duplex ultrasound, and calibrated VFR. Earlybird was found to be a feasible tool for evaluating VFR in AVFs, with a strong correlation and good agreement between the methods used 6. Further development, especially to overcome the limitations with angle dependency, may increase user-friendliness and further improve the accuracy. Earlybird could be a potential valuable tool for surveillance of VFR.
FlowOx™ is a promising device, supplementary to standard care of peripheral arterial disease. Earlybird has been demonstrated to be a feasible device to assess blood flow in healthy individuals, as well as in patients with a range of clinical challenges within the broad segment of vascular disease. Earlybird could be a future tool for clinical decision making during endovascular treatment and a future promising tool for surveillance of hemodialytic vascular access. Further technical and software development of earlybird, may increase user-friendliness and allow for a wide range of clinical applications
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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