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  • Public defence: 2017-08-31 10:15 Auditorium Minus, Uppsala
    Galazka, Martyna A.
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Psychology. Uppsala Child & Babylab.
    Social causality in motion: Visual bias and categorization of social interactions during the observation of chasing in infancy2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Since the seminal work of Fritz Heider and Marienne Simmel (1944) the study of animacy perception, or the perception and attribution of life from the motion of simple geometrical shapes has intrigued researchers. The intrigue for psychologists and vision scientists then and today centered on the stark disconnect between the simplicity of the visual input and the universal richness of the resulting percept.

    Infant research in this domain has become critical in examining the ontological processes behind the formation of animated percepts. To date, little is known about how infants process these kinds of stimuli. While numerous habituation studies have shown sensitivity to animate motion in general, none to date has examined whether infants actually perceive animate displays as social interactions.

    The overarching goal of the present thesis is to answer this question and further augment knowledge about the mechanisms behind the formation of animated percepts in infancy. I, along with my collaborators, do so in three ways, in three separate studies. First, we examined visual attention during online observation of randomly moving geometrical shapes in adults and infants (Study I, using eye tracking). Second, we examine distribution of visual attention in infancy during online observation of non-contact causal interactions, focusing on the most ubiquitous, fitness relevant of interactions – chasing (Study II, using eye tracking). Third, we answer the question whether infants perceive social content in chasing displays by measuring the neural correlates in response to chasing (Study III, using EEG).

    The collective contribution of the present work is also three fold. First, it demonstrates that starting at the end of the first year of life, human visual system is sensitive to cues that efficiently predict an interaction. Second, at 5-months infants begins allocating attention differently across agents within interactions. Finally, attention to specific objects is not due to low-level saliency but the social nature of the interaction. Subsequently, I present the case that perception of social agents is fast, direct, and reflects the workings of a specialized learning mechanisms whose function is the detection of heat-seeking animates in motion. 

    List of papers
    1. Visual Attention to Dynamic Spatial Relations in Infants and Adults
    Open this publication in new window or tab >>Visual Attention to Dynamic Spatial Relations in Infants and Adults
    2016 (English)In: Infancy, ISSN 1525-0008, E-ISSN 1532-7078, Vol. 21, no 1, 90-103 p.Article in journal (Refereed) Published
    Abstract [en]

    Previous research has found that kinematic features of interactions, such as spatial proximity, capture adult visual attention. The current research uses online measures of gaze behavior to determine attentional capture to objects with reduced interobject spacing in adults as well as infants at 5 and 12months. The three age groups observed three identical geometrical shapes that moved randomly. Relative distance between the objects was mapped and intervals of high and low spatial proximity were identified. Findings demonstrate that only adults and 12-month-olds look significantly more at the objects that are close during instances of high spatial proximity, while 5-month-olds look at chance. The findings speak for a developmental trend in oculomotor processes, where a bias to look at objects with high spatial proximity develops within the first year of life.

    National Category
    Psychology
    Identifiers
    urn:nbn:se:uu:diva-268915 (URN)10.1111/infa.12091 (DOI)000368719000005 ()
    Funder
    Swedish Research Council, VR-2011-1528
    Available from: 2015-12-11 Created: 2015-12-11 Last updated: 2017-05-12Bibliographically approved
    2. Infants' preference for individual agents within chasing interactions
    Open this publication in new window or tab >>Infants' preference for individual agents within chasing interactions
    2016 (English)In: Journal of experimental child psychology (Print), ISSN 0022-0965, E-ISSN 1096-0457, Vol. 147, 53-70 p.Article in journal (Refereed) Published
    Abstract [en]

    Infants, like adults, are able to discriminate between chasing and non-chasing interactions when watching animations with simple geometric shapes. But where infants derive the necessary information for discrimination and how chasing detection influences later visual attention has been previously unexplored. Here, using eye tracking, we investigated how 5- and 12-month-old infants (N = 94) distribute their visual attention among individual members within different interactions depending on a type of interaction. Infant gaze was examined when observing animations depicting chasing and following interactions compared with animations displaying randomly moving shapes. Results demonstrate that when observing chasing and following interactions, all infants strongly preferred to attend to the agent that initiates an interaction and trails behind another. Low-level features, such as changes in agent-specific velocity profiles, could not account for this preference (Study 2). Rather, the strong preference for the agent going behind seems to be dependent on the initial goal-directed or "heat-seeking" motion of one agent toward another (Study 3). The current set of experiments suggests that, similar to adults, 5 months-olds' visual attention depends on the motion features of an individual agent within the interaction and is fine-tuned to agents that display goal-directed motion toward other agents.

    Keyword
    Visual attention, Social interactions, Social perception, Infant, Eye tracking, Chasing
    National Category
    Psychology (excluding Applied Psychology)
    Identifiers
    urn:nbn:se:uu:diva-298836 (URN)10.1016/j.jecp.2016.02.010 (DOI)000376698100004 ()27017143 (PubMedID)
    Funder
    Swedish Research Council, VR-2011-1528
    Available from: 2016-07-11 Created: 2016-07-11 Last updated: 2017-05-12Bibliographically approved
    3. How social is the chaser?: Neural correlates of chasing perception in 9-month-old infants
    Open this publication in new window or tab >>How social is the chaser?: Neural correlates of chasing perception in 9-month-old infants
    2016 (English)In: Developmental Cognitive Neuroscience, ISSN 1878-9293, E-ISSN 1878-9307, Vol. 19, 270-278 p.Article in journal (Refereed) Published
    Abstract [en]

    We investigated the neural correlates of chasing perception in infancy to determine whether animated interactions are processed as social events. By using EEG and an ERP design with animations of simple geometric shapes, we examined whether the positive posterior (P400) component, previously found in response to social stimuli, as well as the attention related negative fronto-central component (Nc), differs when infants observed a chaser versus a non-chaser. In Study 1, the chaser was compared to an inanimate object. In Study 2, the chaser was compared to an animate but not chasing agent (randomly moving agent). Results demonstrate no difference in the Nc component, but statistically higher P400 amplitude when the chasing agent was compared to either an inanimate object or a random object. We also find a difference in the N290 component in both studies and in the P200 component in Study 2, when the chasing agent is compared to the randomly moving agent. The present studies demonstrate for the first time that infants' process correlated motion such as chasing as a social interaction. The perception of the chasing agent elicits stronger time-locked responses, denoting a link between motion perception and social cognition.

    Keyword
    P400, Animacy perception, Chasing
    National Category
    Psychology
    Identifiers
    urn:nbn:se:uu:diva-299733 (URN)10.1016/j.dcn.2016.05.0051878 (DOI)000378032000027 ()27258722 (PubMedID)
    Funder
    Swedish Research Council, VR-2011-1528EU, European Research Council, 312292
    Available from: 2016-07-26 Created: 2016-07-26 Last updated: 2017-05-12Bibliographically approved
  • Public defence: 2017-09-01 09:15 Enghoffsalen, Uppsala
    Rosenqvist, Kerstin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Transjugular intrahepatic portosystemic shunt in the treatment of symptomatic portal hypertension2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Portal hypertension (PHT) is a condition with serious complications, such as variceal bleeding, refractory ascites and bowel ischemia. The cause of PHT may be pre-, intra- or post-hepatic. Initial treatment is pressure-reducing drugs and the treatment of acute symptoms.

    Ten patients presented with severe abdominal pain and acute portomesenteric venous thrombosis. Their response to systemic anticoagulation was insufficient. Treatment with primary continuous thrombolysis by a transhepatic or transjugular approach in four patients resulted in major complications, incomplete recanalization and a 75% survival rate. Treatment with repeated transjugular thrombectomy (TT) combined with the creation of a transjugular intrahepatic portosystemic shunt (TIPS) achieved near complete recanalization, prompt symptom relief and 100% survival in five patients treated with this method as the primary intervention. In one patient, treated with TT and TIPS secondary to surgical thrombectomy and bowel resection, the outcome was fatal.

    Nineteen patients with portal vein thrombosis presented with acute or threatening variceal bleeding or refractory ascites. TIPS was feasible in 16 of the 18 patients in whom it was attempted and symptom relief was achieved in the majority of them.

    In 14 patients with Budd-Chiari syndrome, 13 patients were treated with TIPS, four of them after previous liver vein angioplasty. The 5-year transplantation-free survival rate was 100% in patients treated with primary TIPS.

    In 131 patients with variceal bleeding treated with TIPS, the survival at 12 months in patients with and without cirrhosis was 70% and 100% respectively and in accordance with previous studies. A high Child-Pugh score prior to TIPS and severe HE within 12 months after TIPS was related to an increased mortality. The occurrence of HE after TIPS did not correlate with the PSG after TIPS. Re-bleeding within 12 months after TIPS occurred in 10 patients and was associated with TIPS dysfunction.

    In conclusion, endovascular intervention, mainly TIPS, seems to be safe and effective for treating patients with complications of PHT, regardless of the underlying cause of disease and site of venous blood flow obstruction. HE may occur more frequently after TIPS than medical and endoscopic treatment, but is often mild and easily treated. In selected patients with PHT, TIPS may improve survival.

    List of papers
    1. Endovascular treatment of acute and chronic portal vein thrombosis in patients with cirrhotic and non-cirrhotic liver
    Open this publication in new window or tab >>Endovascular treatment of acute and chronic portal vein thrombosis in patients with cirrhotic and non-cirrhotic liver
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    2016 (English)In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 57, no 5, 572-579 p.Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND: Treatment of patients with portal vein thrombosis (PVT) differs due to different etiology and wide range of symptoms but certain patients seems to benefit from endovascular intervention.

    PURPOSE: To assess the safety and efficiency of endovascular treatment of acute and chronic PVT in patients with cirrhotic and non-cirrhotic liver.

    MATERIAL AND METHODS: Twenty-one patients with PVT treated with an endovascular procedure in 2002-2013 were studied retrospectively. Data on etiology, onset and extension of thrombus, presenting symptoms, methods of intervention, portal pressure gradients, complications, recurrence of symptoms, re-interventions, clinical status at latest follow-up, and survival were collected.

    RESULTS: Four non-cirrhotic patients with acute extensive PVT and bowel ischemia were treated with local thrombolysis, in three combined with placement of a transjugular intrahepatic portosystemic shunt (TIPS) placement. Three recovered and have survived more than 6 years. In six non-cirrhotic patients with chronic PVT and acute or threatening variceal bleeding recanalization and TIPS were successful in three and failed in three. Eleven cirrhotic patients with PVT and variceal bleeding or refractory ascites were successfully treated with recanalization and TIPS. Re-intervention was performed in five of these patients and five patients died, three within 12 months of intervention. Four cirrhotic patients had episodes of shunt-related encephalopathy and three had variceal re-bleeding.

    CONCLUSION: TIPS was found to be effective in reducing portal hypertension in patients with PVT. In patients with extensive PVT and bowel ischemia treatment with TIPS combined with thrombolysis should be considered.

    Keyword
    Portal vein; thrombosis; liver cirrhosis; endovascular procedure; retrospective study
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:uu:diva-261206 (URN)10.1177/0284185115595060 (DOI)000374327600010 ()26253926 (PubMedID)
    Available from: 2015-08-31 Created: 2015-08-31 Last updated: 2017-05-10Bibliographically approved
    2. Endovascular treatment of symptomatic Budd-Chiari syndrome - in favour of early transjugular intrahepatic portosystemic shunt.
    Open this publication in new window or tab >>Endovascular treatment of symptomatic Budd-Chiari syndrome - in favour of early transjugular intrahepatic portosystemic shunt.
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    2016 (English)In: European Journal of Gastroenterology and Hepathology, ISSN 0954-691X, E-ISSN 1473-5687, Vol. 28, no 6, 656-660 p.Article in journal (Refereed) Published
    Abstract [en]

    INTRODUCTION: Treatment of Budd-Chiari syndrome (BCS) has shifted from mainly medical treatment, with surgical shunt and orthotopic liver transplantation (OLT) as rescue, to medical treatment combined with an early endovascular intervention in the past two decades.

    PURPOSE: To assess the safety and efficiency of endovascular treatment of symptomatic patients with BCS and to compare mortality with symptomatic BCS patients in the same region treated with only sporadic endovascular techniques.

    METHODS: This was a retrospective review of clinical data, treatment and survival in 14 patients diagnosed with BCS and treated with endovascular methods from 2003 to 2015. A national epidemiology study of BCS from 1986 to 2003 was used for comparison.

    RESULTS: Thirteen of the 14 patients eventually had transjugular intrahepatic portosystemic shunt (TIPS), four after previous liver vein angioplasty. TIPS were performed with polytetrafluoroethylene-covered stents and technical success was 100%. Calculated preinterventional prognostic indices indicated a high risk of TIPS dysfunction, OLT and death. However, only one patient died and one had an OLT, and the 1- and 2-year primary TIPS-patency was 85 and 67%, respectively. Episodes of de-novo hepatic encephalopathy occurred in three patients. Overall 1- and 5-year transplantation-free survival was 100 and 93% compared with 47 and 28%, respectively, in 1986 to 2003.

    CONCLUSION: TIPS seems to be a safe and effective treatment for symptomatic BCS and there is an obvious improvement in transplantation-free survival compared with conservatory medical treatment. It should, therefore, be considered early, as first-line intervention, in patients with insufficient response to medical treatment.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:uu:diva-285913 (URN)10.1097/MEG.0000000000000621 (DOI)000375147100008 ()26958788 (PubMedID)
    Available from: 2016-04-20 Created: 2016-04-20 Last updated: 2017-05-10Bibliographically approved
    3. Repeated thrombectomy through a transjugular intrahepatic portosystemic shunt. An effective and safe way to treat acute portomesenteric venous thrombosis.
    Open this publication in new window or tab >>Repeated thrombectomy through a transjugular intrahepatic portosystemic shunt. An effective and safe way to treat acute portomesenteric venous thrombosis.
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    (English)Manuscript (preprint) (Other academic)
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:uu:diva-321534 (URN)
    Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2017-05-10
    4. Transjugular intrahepatic portosystemic shunt treatment of variceal bleeding in an unselected patient population
    Open this publication in new window or tab >>Transjugular intrahepatic portosystemic shunt treatment of variceal bleeding in an unselected patient population
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    (English)Manuscript (preprint) (Other academic)
    National Category
    Radiology, Nuclear Medicine and Medical Imaging
    Identifiers
    urn:nbn:se:uu:diva-321536 (URN)
    Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2017-05-18
  • Public defence: 2017-09-01 13:00 Hedstrandsalen, Uppsala
    Strandberg, Gunnar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care.
    Experimental Studies on Diagnostic and Therapeutic Aspects of Intraosseous Access2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Reliable access to the circulation is paramount in most medical and surgical emergencies. When venous access cannot be expediently established, intraosseous (IO) access is indicated. This method has a high success rate even in relatively inexperienced hands and there is considerable clinical experience of IO administration of drugs and fluids. There is however limited evidence on the use of IO samples for laboratory analysis. Also, uptake of drugs during shock has not been extensively studied. Further, there have been concerns that analysis of IO samples may damage laboratory equipment. We have studied, in a porcine model, the use of IO samples for point of care analysis of blood gases, acid base parameters and blood chemistries in stable circulation, in experimental septic shock, and in hypovolemia after major hemorrhage, comparing IO samples with arterial and venous samples, and comparing IO samples from different sites. We have also studied coagulation assays on IO samples in stable circulation and after major hemorrhage. Furthermore, we have compared IO and intravenous administration of antibiotics in experimental sepsis.

    Average differences between IO and arterial/venous samples varied between the studied analytes. During stable circulation, average IO levels of blood gases, acid-base parameters, hemoglobin/hematocrit and several blood chemistries approximated venous levels relatively well. Differences in acid-base and blood gas parameters, and lactate, were more pronounced in hypovolemia, as well as in sepsis. The dispersion of the differences was often relatively large, indicating limited precision. Average differences between two intraosseous sites were small.

    Intraosseous samples were clinically hypercoagulable with a strong tendency to clot in vitro, and thromboelastography demonstrated shortened reaction times compared with venous samples. Major bleeding and hemodilution moderately affected the studied coagulation parameters.

    In endotoxemic animals with circulatory instability, concentrations of cefotaxime and gentamicin in samples from the pulmonary artery were comparable at 5 minutes after intraosseous and intravenous administration, and during a 3 hour observation period.

    In summary, agreement between analytes in intraosseous and conventional blood samples was variable and often unpredictable, especially during circulatory compromise. Intraosseous samples clinically appeared hypercoagulable, and thromboelastography confirmed this. High and comparable concentrations of cefotaxime and gentamicin were found after intraosseous and intravenous administration of equivalent doses, suggesting that uptake is acceptable during septic instability.  

    List of papers
    1. Analysis of intraosseous samples using point of care technology: an experimental study in the anaesthetised pig
    Open this publication in new window or tab >>Analysis of intraosseous samples using point of care technology: an experimental study in the anaesthetised pig
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    2012 (English)In: Resuscitation, ISSN 0300-9572, E-ISSN 1873-1570, Vol. 83, no 11, 1381-1385 p.Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND:

    Intraosseous access is an essential method in emergency medicine when other forms of vascular access are unavailable and there is an urgent need for fluid or drug therapy. A number of publications have discussed the suitability of using intraosseous access for laboratory testing. We aimed to further evaluate this issue and to study the accuracy and precision of intraosseous measurements.

    METHODS:

    Five healthy, anaesthetised pigs were instrumented with bilateral tibial intraosseous cannulae and an arterial catheter. Samples were collected hourly for 6h and analysed for blood gases, acid base status, haemoglobin and electrolytes using an I-Stat(®) point of care analyser.

    RESULTS:

    There was no clinically relevant difference between results from left and right intraosseous sites. The variability of the intraosseous sample values, measured as the coefficient of variance (CV), was maximally 11%, and smaller than for the arterial sample values for all variables except SO(2). For most variables, there seems to be some degree of systematic difference between intraosseous and arterial results. However, the direction of this difference seems to be predictable.

    CONCLUSION:

    Based on our findings in this animal model, cartridge based point of care instruments appear suitable for the analysis of intraosseous samples. The agreement between intraosseous and arterial analysis seems to be good enough for the method to be clinically useful. The precision, quantified in terms of CV, is at least as good for intraosseous as for arterial analysis. There is no clinically important difference between samples from left and right tibia, indicating a good reproducibility.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:uu:diva-181455 (URN)10.1016/j.resuscitation.2012.04.007 (DOI)000311793100023 ()22542768 (PubMedID)
    Available from: 2012-09-24 Created: 2012-09-24 Last updated: 2017-05-08Bibliographically approved
    2. Analysis of intraosseous samples in endotoxemic shock: an experimental study in the anaesthetised pig
    Open this publication in new window or tab >>Analysis of intraosseous samples in endotoxemic shock: an experimental study in the anaesthetised pig
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    2014 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 58, no 3, 337-344 p.Article in journal (Refereed) Published
    Abstract [en]

    Background

    Intraosseous (IO) access is used in emergency situations to allow rapid initiation of treatment. IO access is also sometimes used for blood sampling, although data on accuracy of such sampling in critical illness are limited. There is also a potential risk that bone marrow fragments in IO samples may damage laboratory equipment. It is ethically questionable to perform a simultaneous comparison between IO and arterial/venous sampling in critically ill humans. We have, thus, studied the analytical performance of IO sampling in a porcine septic shock model using a cartridge-based analyser.

    Methods

    Eight pigs with endotoxin-induced septic shock were sampled hourly for 6 h, and analysed for blood gases, acid base status, haemoglobin, glucose and lactate using point of care instruments. Samples were taken from three IO cannulae (tibia bilaterally, one with infusion, and humerus), one arterial and one venous. An interaction test was used to assess changes in agreement between methods over time. Bland–Altman plots were constructed to study bias between methods.

    Results

    There were, to a varying extent, differences between IO and arterial/venous levels for all studied variables, but agreement did not change significantly during the experiment. A general finding was a large dispersion of differences between methods.

    Conclusions

    IO sample values should be treated with caution in this setting but may add useful information to the clinical picture. The tibia or humerus may be used for sampling. IO infusion decreases agreement, thus sampling during infusion should be avoided.

    National Category
    Anesthesiology and Intensive Care
    Identifiers
    urn:nbn:se:uu:diva-220973 (URN)10.1111/aas.12274 (DOI)000331406500011 ()
    Available from: 2014-03-25 Created: 2014-03-24 Last updated: 2017-05-08Bibliographically approved
    3. Intraosseous and intravenous administration of antibiotics yields comparable plasma concentrations during experimental septic shock
    Open this publication in new window or tab >>Intraosseous and intravenous administration of antibiotics yields comparable plasma concentrations during experimental septic shock
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    2015 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 59, no 3, 346-353 p.Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND: We aimed to investigate whether comparable antibiotic concentrations could be reached with intraosseous and intravenous administration during septic shock.

    METHODS: In this randomized, prospective experimental study conducted at an animal research laboratory at the University Hospital of Uppsala, eight anesthetized pigs, weighing 21.2 to 29.1 kg (mean: 25.2 ± 2.3 kg), received endotoxin infusion at 4 μg/kg/h for 6 h. At the onset of clinical shock, alternatively after 3 h of endotoxemia, they received 75 mg/kg of cefotaxime and 7 mg/kg of gentamicin either in a proximal tibial intraosseous catheter or in a peripheral intravenous catheter. Mixed venous samples were taken after 5, 15, 30, 60, 120 and 180 min and analyzed for antibiotic concentrations.

    RESULTS: For both antibiotics, plasma concentrations after intraosseous and intravenous administration followed similar curves throughout the observation period, and peak concentrations were comparable. Mean concentration area under the curve (AUC mg × h/l) for cefotaxime was 108.1 ± 19.5 after intraosseous and 116.5 ± 11.1 after intravenous administration; ratio 0.93, (95% CI 0.71-1.19). Mean AUC for gentamicin was 28.1 ± 6.8 for intraosseous and 32.2 ± 3.5 for intravenous administration; ratio 0.87 (95% CI 0.62-1.19).

    CONCLUSIONS: In this porcine septic shock model, intraosseous and intravenous administration of gentamicin and cefotaxime yielded comparable concentrations. In an emergency, intraosseous administration of these antibiotics may be considered in severe infections when venous access is difficult.

    National Category
    Anesthesiology and Intensive Care
    Identifiers
    urn:nbn:se:uu:diva-240273 (URN)10.1111/aas.12454 (DOI)000349604000009 ()25557933 (PubMedID)
    Available from: 2015-01-06 Created: 2015-01-06 Last updated: 2017-05-08Bibliographically approved
    4. Analysis of Thromboelastography, PT, APTT and Fibrinogen in Intraosseous and Venous Samples: An Experimental Study
    Open this publication in new window or tab >>Analysis of Thromboelastography, PT, APTT and Fibrinogen in Intraosseous and Venous Samples: An Experimental Study
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    2016 (English)In: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, ISSN 1757-7241, E-ISSN 1757-7241, Vol. 24, 131Article in journal (Refereed) Published
    Abstract [en]

    Background:Laboratory analysis of coagulation is often important in emergencies. If vascular access is challenging,intraosseous catheterization may be necessary for treatment. We studied the analysis of coagulation parameters inintraosseous aspirate during stable conditions and after major haemorrhage in a porcine model.Methods:Ten anesthetized pigs received central venous and intraosseous catheters and samples were taken foranalysis of thromboelastography (TEG), prothrombin time (PT), activated partial thromboplastin time (APTT) andfibrinogen concentration. Analyses were repeated after removal of 50 % of the calculated blood volume andresuscitation with crystalloid. Intraosseous and venous values were compared.Results:Bleeding and resuscitation resulted in haemodilution and hypotension. Median TEG reaction time wasshorter in intraosseous than in venous samples before (1.6 vs 4.6 min) and after (1.6 vs 4.7 min) haemodilution.Median maximal amplitude was smaller in intraosseous samples at baseline (68.3 vs 76.4 mm). No major differenceswere demonstrated for the other TEG parameters. The intraosseous samples often coagulated in vitro, makinganalysis of PT, APTT and fibrinogen difficult. After haemodilution, TEG maximal amplitude andα-angle, andfibrinogen concentration, were decreased and PT increased.Discussion:The intraosseous samples were clinically hypercoagulable and the TEG demonstrated a shortenedreaction time. The reason for this may hypothetically be found in the composition of the IO aspirate or in thesampling technique. After 50 % haemorrhage and haemodilution, a clinically relevant decrease in fibrinogenconcentration and a lower TEG maximal amplitude were observed.Conclusions:Although the sample is small, these data indicate that intraosseous samples are hypercoagulable,which may limit their usefulness for coagulation studies. Major haemodilution only moderately affected the studied parameters.

    Keyword
    Blood coagulation; Haemorrhage; Infusions; Intraosseous; Thrombelastography
    National Category
    Anesthesiology and Intensive Care
    Identifiers
    urn:nbn:se:uu:diva-306587 (URN)10.1186/s13049-016-0318-0 (DOI)000386860300001 ()
    Available from: 2016-10-29 Created: 2016-10-29 Last updated: 2017-05-08Bibliographically approved
    5. Comparison of Intraosseous, Arterial and Venous Blood Sampling for Laboratory Analysis in Haemorrhagic Shock
    Open this publication in new window or tab >>Comparison of Intraosseous, Arterial and Venous Blood Sampling for Laboratory Analysis in Haemorrhagic Shock
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Abstract

    Introduction Intraosseous (IO) access is often indicated for administration of drugs and fluids in emergencies when venous access is challenging. There is no consensus regarding which laboratory analyses may be performed on IO aspirates, and research on hemodynamically unstable subjects is limited.

    Methods 12 anaesthetised pigs were sampled from IO, venous and arterial accesses during stable circulation and after haemorrhage corresponding to 20% and 40% of the blood volume. Samples were analysed for blood gases and acid-base status, electrolytes, haematocrit, creatinine, glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyltransferase (γ-GT), alkaline phosphatase (ALP) and creatine kinase (CK).

    Results Average differences of blood gases and acid-base parameters, sodium, creatinine, haematocrit, ALT and γ-GT and between IO and venous samples were small at baseline and after haemorrhage while differences for lactate and glucose increased with hypovolaemia. Both IO-arterial and venoarterial differences in acid-base parameters increased with hypovolaemia. Dispersions of differences were often large.

    Conclusions Average levels of blood gases, acid base parameters, haematocrit, creatinine and ALT, but not lactate and glucose, were similar in IO and venous samples in hypovolaemia. However, precision was limited, indicating that IO test results should be confirmed when other vascular access is established, and that analysis of IO samples should be limited to acute situations and not used for detailed diagnostics in this setting.

    Keyword
    Intraosseous access, shock
    National Category
    Anesthesiology and Intensive Care
    Research subject
    Anaesthesiology and Intensive Care
    Identifiers
    urn:nbn:se:uu:diva-321402 (URN)
    Available from: 2017-05-04 Created: 2017-05-04 Last updated: 2017-05-04
  • Public defence: 2017-09-01 13:15 Polhemsalen, Uppsala
    Wang, Liguo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Modelling and Advanced Control of Fully Coupled Wave Energy Converters Subject to Constraints: the Wave-to-wire Approach2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Ocean wave energy is a promising renewable source to contribute to supplying the world’s energy demand. The Division of Electricity at Uppsala University is developing a technology to capture energy from ocean waves with a wave energy converter (WEC) consisting of a linear permanent magnet generator and a point absorber. The linear generator is placed on sea bed and is driven directly by the floating absorber. Since March 2006, multiple wave energy converters have been deployed on the Swedish west coast outside the town of Lysekil. The technology is verified by long-term operation during at sea and satisfactory reliability of the electricity generation.

    This thesis focuses on developing advanced control strategies for fully coupled wave energy converters subject to constraints. A nonlinear control strategy is studied in detail for a single WEC subject to constraints under regular and irregular waves. Besides, two coordinated control strategies are developed to investigate the performance of a wave energy farm subject to constraints. The performance of the WECs using these control strategies are investigated in case studies, and optimal PTO damping coefficients are found to maximize the output power. The results show that these control strategies can significantly improve the performance of the WECs, in terms of mean power, compared to a conventional control.

    Besides these control strategies, a wave-to-wire simulation platform is built to study the power generation control of the WEC subject to constraints.  The wave-to-wire simulation platform allows both nonlinear and linear control force. The results show that there is a good agreement between the desired value and the actual value after advanced control.

    List of papers
    1. Constrained optimal control of a point absorber wave energy converter with linear generator
    Open this publication in new window or tab >>Constrained optimal control of a point absorber wave energy converter with linear generator
    2015 (English)In: Journal of Renewable and Sustainable Energy, ISSN 1941-7012, E-ISSN 1941-7012, Vol. 7, 043127Article in journal (Refereed) Published
    Abstract [en]

    This paper investigates a method for optimal control of a point absorbing wave energy converter by considering the constraints on motions and forces in the time domain. The problem is converted to an optimization problem with the cost function being convex quadratic and the constraints being nonlinear. The influence of the constraints on the converter is studied, and the results are compared with uncontrolled cases and established theoretical bounds. Since this method is based on the knowledge of the future sea state or the excitation force, the influence of the prediction horizon is indicated. The resulting performance of the wave energy converter under different regular waves shows that this method leads to a substantial increase in conversion efficiency.

    Keyword
    wave energy
    National Category
    Environmental Engineering
    Research subject
    Engineering Science
    Identifiers
    urn:nbn:se:uu:diva-263980 (URN)10.1063/1.4928677 (DOI)000360655500046 ()
    Funder
    Swedish Energy Agency
    Available from: 2015-10-05 Created: 2015-10-05 Last updated: 2017-04-26Bibliographically approved
    2. Nonlinear Passive Control of a Wave Energy Converter Subject to Constraints in Irregular Waves
    Open this publication in new window or tab >>Nonlinear Passive Control of a Wave Energy Converter Subject to Constraints in Irregular Waves
    2015 (English)In: Energies, ISSN 1996-1073, Vol. 8, no 7, 6528-6542 p.Article in journal (Refereed) Published
    National Category
    Other Engineering and Technologies
    Identifiers
    urn:nbn:se:uu:diva-258502 (URN)10.3390/en8076528 (DOI)000359897800015 ()
    Funder
    Swedish Energy Agency
    Available from: 2015-07-14 Created: 2015-07-14 Last updated: 2017-04-26Bibliographically approved
    3. Constrained Optimal Control of Single and Arrays of Point-Absorbing Wave Energy Converters
    Open this publication in new window or tab >>Constrained Optimal Control of Single and Arrays of Point-Absorbing Wave Energy Converters
    Show others...
    2016 (English)Conference paper (Refereed)
    National Category
    Ocean and River Engineering
    Identifiers
    urn:nbn:se:uu:diva-297190 (URN)
    Conference
    Marine Energy Technology Symposium
    Available from: 2016-06-21 Created: 2016-06-21 Last updated: 2017-04-26Bibliographically approved
    4. Coordinated Control of Wave Energy Converters Subject to Motion Constraints
    Open this publication in new window or tab >>Coordinated Control of Wave Energy Converters Subject to Motion Constraints
    2016 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 9, no 6, 475Article in journal (Refereed) Published
    Abstract [en]

    In this paper, a generic coordinated control method for wave energy converters is proposed, and the constraints on motion amplitudes and the hydrodynamic interaction between converters are considered. The objective of the control problem is to maximize the energy converted from ocean waves, and this is achieved by coordinating the power take-off (PTO) damping of each wave energy converter in the frequency domain in each sea state. In a case study, a wave energy farm consisting of four converters based on the concept developed by Uppsala University is studied. In the solution, motion constraints, including constraints on the amplitudes of displacement and velocity, are included. Twelve months of sea states, based on measured wave data at the Lysekil test site on the Swedish west coast, are used in the simulation to evaluate the performance of the wave energy farm using the new method. Results from the new coordinated control method and traditional control method are compared, indicating that the coordinated control of wave energy converters is an effective way to improve the energy production of wave energy farm in harmonic waves.

    Place, publisher, year, edition, pages
    MDPI: , 2016
    Keyword
    wave energy farm; coordinated control; optimal damping; motion constraints; frequency domain
    National Category
    Ocean and River Engineering
    Identifiers
    urn:nbn:se:uu:diva-297187 (URN)10.3390/en9060475 (DOI)000378854400088 ()
    Funder
    Swedish Energy AgencyStandUpSwedish National Infrastructure for Computing (SNIC)
    Available from: 2016-06-21 Created: 2016-06-21 Last updated: 2017-04-26Bibliographically approved
    5. Performance of arrays of direct-driven wave energy converters under optimal power take-off damping
    Open this publication in new window or tab >>Performance of arrays of direct-driven wave energy converters under optimal power take-off damping
    2016 (English)In: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 6, 085313Article in journal (Refereed) Published
    Abstract [en]

    It is well known that the total power converted by a wave energy farm is influenced by the hydrodynamic interactions between wave energy converters, especially when they are close to each other. Therefore, to improve the performance of a wave energy farm, the hydrodynamic interaction between converters must be considered, which can be influenced by the power take-off damping of individual converters. In this paper, the performance of arrays of wave energy converters under optimal hydrodynamic interaction and power take-off damping is investigated. This is achieved by coordinating the power take-off damping of individual converters, resulting in optimal hydrodynamic interaction as well as higher production of time-averaged power converted by the farm. Physical constraints on motion amplitudes are considered in the solution, which is required for the practical implementation of wave energy converters. Results indicate that the natural frequency of a wave energy converter under optimal damping will not vary with sea states, but the production performance of a wave energy farm can be improved significantly while satisfying the motion constraints.

    National Category
    Water Engineering
    Identifiers
    urn:nbn:se:uu:diva-301092 (URN)10.1063/1.4961498 (DOI)000383909100078 ()
    Projects
    Performance and Survivability of Wave power Farm
    Funder
    Swedish Energy Agency, 40421-1
    Available from: 2016-08-17 Created: 2016-08-17 Last updated: 2017-04-26Bibliographically approved
    6. Review of control strategies for wave energy conversion systems and their validation: the wave-to-wire approach
    Open this publication in new window or tab >>Review of control strategies for wave energy conversion systems and their validation: the wave-to-wire approach
    (English)Article in journal, Editorial material (Refereed) Submitted
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-320904 (URN)
    Available from: 2017-04-26 Created: 2017-04-26 Last updated: 2017-04-26
  • Public defence: 2017-09-01 13:15 Room C8:305, Uppsala
    Inturi, Raviteja
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Functional characterization of the human adenovirus pVII protein and non-coding VA RNAI2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human adenovirus (HAdV) is a common pathogen causing a broad spectrum of diseases. HAdV encodes the pVII protein, which is involved in nuclear delivery, protection and expression of viral DNA. To suppress the cellular interferon (IFN) and RNA interference (RNAi) systems, HAdVs encode non-coding virus-associated (VA) RNAs. In this thesis we have investigated the functional significance of the pVII protein and VA RNAI in HAdV-5 infected cells.

    We report that the propeptide module is the destabilizing element targeting the precursor pVII protein for proteasomal degradation. We also found that the Cul3-based E3 ubiquitin ligase complex alter the precursor pVII protein stability via binding to the propeptide sequence. In addition, we show that inhibition of the Cul3 protein reduces HAdV-5 E1A gene expression. Collectively, our results suggest a novel function for the pVII propeptide module and involvement of Cul3 in viral E1A gene expression.

    Our studies show that the cellular E3 ubiquitin ligase MKRN1 is a novel pVII interacting protein in HAdV-5 infected cells. MKRN1 expression reduced the pVII protein accumulation in virus-infected cells and affected infectious virus formation. Surprisingly, the endogenous MKRN1 protein underwent proteasomal degradation during the prolonged HAdV-5 infection. Furthermore, the precursor pVII protein enhanced MKRN1 self-ubiquitination, suggesting the direct involvement of pVII in the initiation of MKRN1 degradation. Hence, we propose that the MKRN1 is a novel antiviral protein and that HAdV-5 infection counteracts its antiviral activity.

    In papers III and IV, we tested the ability of various plant and animal virus encoded RNAi/miRNA and IFN suppressor proteins to functionally substitute for the HAdV-5 VA RNAI. Our results revealed that the Vaccinia virus E3L protein was able to partially substitute for the HAdV-5 VA RNAI functions in virus-infected cells. Interestingly, the E3L protein rescued the translational defect but did not stimulate viral capsid mRNA accumulation observed with VA RNA. Additionally, we show that the HAdV-4 and HAdV-37 VA RNAI are more effective in virus replication compared to HAdV-5 and HAdV-12 VA RNAI. In paper IV, we employed a novel triplex-specific probing assay, based on the intercalating and cleaving agent benzoquinoquinaxline 1,10-phenanthroline (BQQ-OP), to unravel triplex structure formation in 
VA RNAI. The BQQ-OP cleavage of HAdV-4 VA RNAI indicates that a potential 
triplex is formed involving the highly conserved stem 4 of the central domain and side 
stem 7. Further, the integrity of HAdV-4 VA RNAI stem 7 contributes to the virus growth in vivo.

    List of papers
    1. Adenovirus Precursor pVII Protein Stability Is Regulated By Its Propeptide Sequence
    Open this publication in new window or tab >>Adenovirus Precursor pVII Protein Stability Is Regulated By Its Propeptide Sequence
    2013 (English)In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 11, e80617- p.Article in journal (Refereed) Published
    Abstract [en]

    Adenovirus encodes for the pVII protein, which interacts and modulates virus DNA structure in the infected cells. The pVII protein is synthesized as the precursor protein and undergoes proteolytic processing by viral proteinase Avp, leading to release of a propeptide sequence and accumulation of the mature VII protein. Here we elucidate the molecular functions of the propeptide sequence present in the precursor pVII protein. The results show that the propeptide is the destabilizing element targeting the precursor pVII protein for proteasomal degradation. Our data further indicate that the propeptide sequence and the lysine residues K26 and K27 regulate the precursor pVII protein stability in a co-dependent manner. We also provide evidence that the Cullin-3 E3 ubiquitin ligase complex alters the precursor pVII protein stability by association with the propeptide sequence. In addition, we show that inactivation of the Cullin-3 protein activity reduces adenovirus E1A gene expression during early phase of virus infection. Collectively, our results indicate a novel function of the adenovirus propeptide sequence and involvement of Cullin-3 in adenovirus gene expression.

    Keyword
    Adenovirus, pro-peptide, pVII, cullin3, protein stability
    National Category
    Microbiology
    Research subject
    Microbiology; Biochemistry
    Identifiers
    urn:nbn:se:uu:diva-212439 (URN)10.1371/journal.pone.0080617 (DOI)000327258600074 ()
    Funder
    Swedish Research Council, K2012-99X-21959-01-3, 2006-5038-36531-16Swedish Cancer Society, 12 0504
    Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2017-05-09Bibliographically approved
    2. Human adenovirus infection counteracts the anti-viral activity of the cellular MKRN1 E3 ubiquitin ligase
    Open this publication in new window or tab >>Human adenovirus infection counteracts the anti-viral activity of the cellular MKRN1 E3 ubiquitin ligase
    Show others...
    (English)Article in journal (Refereed) Submitted
    National Category
    Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
    Identifiers
    urn:nbn:se:uu:diva-321638 (URN)
    Available from: 2017-05-09 Created: 2017-05-09 Last updated: 2017-05-09
    3. Complementation of the human adenovirus type 5 VA RNAI defect by the Vaccinia virus E3L protein and serotype-specific VA RNAIs
    Open this publication in new window or tab >>Complementation of the human adenovirus type 5 VA RNAI defect by the Vaccinia virus E3L protein and serotype-specific VA RNAIs
    2015 (English)In: Virology, ISSN 0042-6822, E-ISSN 1096-0341, Vol. 485, 25-35 p.Article in journal (Refereed) Published
    Abstract [en]

    Human adenoviruses (HAdVs) encode for multifunctional non-coding virus-associated (VA) RNAs, which function as powerful suppressors of the cellular interferon (IFN) and RNA interference (RNAi) systems. In this study we tested the ability of various plant and animal virus encoded RNAi and IFN suppressor proteins to functionally substitute for the HAdV-5 VA RNAI. Our results revealed that only the Vaccinia virus (VACV) E3L protein was able to substitute for the HAdV-5 VA RNAI functions in virus-infected cells. Interestingly, the E3L protein rescues the translational defect but does not stimulate viral capsid mRNA accumulation observed with VA RNA. We further show that the E3L C-terminal region containing the dsRNA-binding domain is needed to enhance VA RNAI mutant virus replication. Additionally, we show that the HAdV-4 and HAdV-37 VA RNAI are more effective than the HAdV-5 VA RNAI in rescuing virus replication.

    Keyword
    Adenovirus, Vaccinia virus, interferon, PKR, RNAi
    National Category
    Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
    Research subject
    Medical Virology
    Identifiers
    urn:nbn:se:uu:diva-258879 (URN)10.1016/j.virol.2015.07.002 (DOI)000363993100003 ()
    Funder
    Swedish Cancer Society, 12 0504, 13 0469Swedish Research Council, K2012–999X-21959-01-301–3Åke Wiberg Foundation, M14-01555
    Available from: 2015-07-21 Created: 2015-07-21 Last updated: 2017-05-09Bibliographically approved
    4. RNA triplex formation in human adenovirus type 4 VA RNAI and its implication on virus growth
    Open this publication in new window or tab >>RNA triplex formation in human adenovirus type 4 VA RNAI and its implication on virus growth
    (English)Article in journal (Refereed) Submitted
    National Category
    Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
    Identifiers
    urn:nbn:se:uu:diva-321639 (URN)
    Available from: 2017-05-09 Created: 2017-05-09 Last updated: 2017-05-09
  • Public defence: 2017-09-04 13:30 room 132:028, Stockholm
    Chen-Lin, Xinyi
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Physics. Nordita.
    Non-conformal gauge/string duality: A rigorous case study2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The gauge/string duality, a.k.a. the holographic principle is a profound assertion that emerged from string theory. It relates strongly-coupled gauge theories to weakly coupled string theories living in a higher-dimensional curved geometry. Nevertheless, it is a conjecture, and only a few instances of its more concrete form, the AdS/CFT correspondence, are well-understood. The most well-studied example is the duality between N=4 SYM, which is a CFT, and type IIB string theory in AdS5xS5 background. Generalization to less symmetric cases is a must, and the next logical step is to add a mass scale to N=4 SYM, therefore breaking its conformal symmetry and leading to N=2* SYM, the theory we study in this thesis. It is supersymmetric enough to employ the powerful localization method that reduces its partition function to a matrix model. We will see that the mass scale causes non-trivial phase structures in its vacuum configuration, visible in the holographic regime. We will probe them using Wilson loops in different representations of the gauge group. On the other hand, the dual supergravity background was derived by Pilch-Warner, making N=2* theory an explicitly testable non-conformal holographic case, which is a rare example. We will prove that the duality works for the dual observables (string action, D-branes) we managed to compute, even at a quantum-level.

    List of papers
    1. Quantum String Test of Nonconformal Holography
    Open this publication in new window or tab >>Quantum String Test of Nonconformal Holography
    2017 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 04, 95Article in journal (Refereed) Published
    Abstract [en]

    We compute Lüscher corrections to the effective string tension in the PilchWarner background, holographically dual to N" style="position: relative;" tabindex="0" id="MathJax-Element-1-Frame" class="MathJax">N = 2 supersymmetric Yang-Mills theory. The same quantity can be calculated directly from field theory by solving the localization matrix model at large-N . We find complete agreement between the field-theory predictions and explicit string-theory calculation at strong coupling.

    National Category
    Subatomic Physics
    Identifiers
    urn:nbn:se:uu:diva-321871 (URN)10.1007/JHEP04(2017)095 (DOI)
    Available from: 2017-05-11 Created: 2017-05-11 Last updated: 2017-05-14Bibliographically approved
    2. Symmetric Wilson Loops beyond leading order
    Open this publication in new window or tab >>Symmetric Wilson Loops beyond leading order
    2016 (English)In: SciPost Physics, ISSN 2542-4653, Vol. 1, no 2, 013Article in journal (Refereed) Published
    Abstract [en]

    We study the circular Wilson loop in the symmetric representation of U(N) in N=4 super-Yang-Mills (SYM). In the large N limit, we computed the exponentially-suppressed corrections for strong coupling, which suggests non-perturbative physics in the dual holographic theory. We also computed the next-to-leading order term in 1/N, and the result matches with the exact result from the k-fundamental representation.

    National Category
    Other Physics Topics
    Identifiers
    urn:nbn:se:uu:diva-321872 (URN)10.21468/SciPostPhys.1.2.013 (DOI)
    Available from: 2017-05-11 Created: 2017-05-11 Last updated: 2017-05-14Bibliographically approved
    3. Holographic Wilson loops in symmetric representations in N=2*super-Yang-Mills theory
    Open this publication in new window or tab >>Holographic Wilson loops in symmetric representations in N=2*super-Yang-Mills theory
    2016 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 2, 109Article in journal (Refereed) Published
    Abstract [en]

    We construct the D3-brane solution in the holographic dual of the N = 2* theory that describes Wilson lines in symmetric representations of the gauge group. The results perfectly agree with the direct field-theory predictions based on localization.

    Keyword
    Gauge-gravity correspondence, D-branes, AdS-CFT Correspondence
    National Category
    Other Physics Topics
    Identifiers
    urn:nbn:se:uu:diva-282320 (URN)10.1007/JHEP02(2016)109 (DOI)000370849500001 ()
    Funder
    EU, FP7, Seventh Framework Programme, 317089EU, European Research Council, 341222Swedish Research Council, 2013-4329
    Available from: 2016-04-05 Created: 2016-04-05 Last updated: 2017-05-14Bibliographically approved
    4. Higher rank Wilson loops in N=2*super-Yang-Mills theory
    Open this publication in new window or tab >>Higher rank Wilson loops in N=2*super-Yang-Mills theory
    2015 (English)In: Journal of High Energy Physics (JHEP), ISSN 1029-8479, E-ISSN 1126-6708, no 3, 147Article in journal (Refereed) Published
    Abstract [en]

    The N = 2* Super-Yang-Mills theory (SYM*) undergoes an infinite sequence of large-N quantum phase transitions. We compute expectation values of Wilson loops in k-symmetric and antisymmetric representations of the SU(N) gauge group in this theory and show that the same phenomenon that causes the phase transitions at finite coupling leads to a non-analytic dependence of Wilson loops on k/N when the coupling is strictly infinite, thus making the higher-representation Wilson loops ideal holographic probes of the non-trivial phase structure of SYM*.

    Keyword
    Matrix Models, Wilson, 't Hooft and Polyakov loops, AdS-CFT Correspondence, Strong Coupling Expansion
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-252000 (URN)10.1007/JHEP03(2015)147 (DOI)000351751200007 ()
    Funder
    Swedish Research Council, 2013-4329
    Available from: 2015-05-08 Created: 2015-04-28 Last updated: 2017-05-14Bibliographically approved
    5. N=2*super-Yang-Mills theory at strong coupling
    Open this publication in new window or tab >>N=2*super-Yang-Mills theory at strong coupling
    2014 (English)In: Journal of High Energy Physics (JHEP), ISSN 1029-8479, E-ISSN 1126-6708, no 11, 057- p.Article in journal (Refereed) Published
    Abstract [en]

    The planar N = 2* Super-Yang-Mills (SYM) theory is solved at large 't Hooft coupling using localization on S-4. The solution permits detailed investigation of the resonance phenomena responsible for quantum phase transitions in infinite volume, and leads to quantitative predictions for the semiclassical string dual of the N = 2* theory.

    Keyword
    Matrix Models, Gauge-gravity correspondence, AdS-CFT Correspondence, 1/N Expansion
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-245554 (URN)10.1007/JHEP11(2014)057 (DOI)000347908000004 ()
    Available from: 2015-02-27 Created: 2015-02-26 Last updated: 2017-05-14Bibliographically approved