74 research outputs found

    Colour change in traumatised anterior permanent teeth. A prospective cohort observational study

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    Background: There is limited information about colour change following traumatic dental injuries (TDI), and any variable associated with discolouration. It is now increasingly recognised that children’s perception and satisfaction are important and may provide an insight into the psychosocial impact of their oral health and their wider quality of life. Therefore, research to quantify colour change with time following TDI and the patient’s perception is important. This study was designed to identify any association between clinical variables and discolouration following TDI. Aim: To investigate the change in colour of permanent teeth following TDI in children. To explore what variables are associated with discolouration. To examine methods of measuring colour change including IKAM system (objective measure), the use of a shade guide (clinical pseudo objective measure), patient’s perception (patient reported measure) and to evaluate the agreement between these three methodologies. Method: Children following TDI were invited to participate in an observational prospective cohort. Colour change was measured using patients’ perception, investigator’s perception (using a shade guide) and an objective digital system (IKAM). Measurements were taken at baseline, 3 months and 6 months following the TDI with IKAM providing objective CIELAB colour scores. Results: Thirty-nine children, with 73 traumatised teeth, completed the study. Twenty-six children attended two follow-up reviews comprising 52 teeth, and thirteen children attended for one follow-up visit only with 21 teeth. A heterogenous sample of TDI was recruited including various types of hard tissue injuries and periodontal injuries with variable pulpal survival and periodontal healing outcomes. At the last review (n=73 teeth) the objective overall colour change was ΔE 5.45 (SD +/- 2.80) with a mean change in ΔL* 0.74 (lighter), Δa* 0.69 (redder) and Δb* 1.73 (yellower). There was little consistency between patients reported colour change and that recorded by the investigator using a shade guide. There was no significant difference in ΔE values as measured by IKAM in comparison with the patients’ or investigator’s perception. Conclusions: Following TDI, there was an observable colour change identified by an objective measure, IKAM. On average, teeth got predominantly yellow and to a lesser extent lighter and redder. Patients and investigator measures were inconsistent when compared to the objective measure (IKAM). No variables were identified to be associated with colour change. However several variables came to significance (p<0.05). These variables were; time interval between the baseline assessment and the final review, presence of hard tissue injury, splinting, and restoration placed at or before baseline

    Simultaneous Stabilization Of Power System Using UPFC-Based Controllers

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    This article studies the use of robust UPFC-based stabilizers to damp low frequency oscillations. The potential of the UPFC-based stabilizers to enhance the dynamic stability is evaluated by singular value decomposition. Particle swarm optimization technique is used to optimize the parameters of each stabilizer, first individually, then concurrently. To ensure the robustness of the proposed stabilizers, the design process considers a wide range of operating conditions. The effectiveness of the proposed controllers is verified through several linear and nonlinear analysis techniques. These techniques prove that the coordinated design of UPFC-based stabilizers is superior over any of the individual designs

    Simultaneous Stabilization Of Power System Using UPFC-Based Controllers

    Get PDF
    This article studies the use of robust UPFC-based stabilizers to damp low frequency oscillations. The potential of the UPFC-based stabilizers to enhance the dynamic stability is evaluated by singular value decomposition. Particle swarm optimization technique is used to optimize the parameters of each stabilizer, first individually, then concurrently. To ensure the robustness of the proposed stabilizers, the design process considers a wide range of operating conditions. The effectiveness of the proposed controllers is verified through several linear and nonlinear analysis techniques. These techniques prove that the coordinated design of UPFC-based stabilizers is superior over any of the individual designs

    Vascular complications following intra-aortic balloon pump implantation: an updated review

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    Background: The use of the intra-aortic balloon pump (IABP) as a support device remains controversial due to the fact that a number of studies have shown no benefit in end mortality whilst using this device. One of the reasons for this could be the increase in vascular complications when using the pump. Therefore, the aim of the present review was to assess the current literature available with regards to IABP vascular complications during the clinical situation. Methods: A literature search was performed, searching for IABP complications in adult human studies between 1990 and 2016. Results: A total of 20 reports were identified as fitting the criteria of this study. The majority of vascular complications were limb ischemia, bleeding or mesenteric ischemia. The overall incidence of vascular complications ranged from 0.94% to 31.1%. Diabetes, peripheral vascular disease and hypertension, as well as smoking were all identified as risk factors for complications following IABP. Furthermore, studies supported the use of sheathless balloon insertion to reduce the risk of complications. Conclusion: Major vascular complications, including limb and mesenteric ischemia as well as bleeding and hemorrhage, have been associated with IABP. However, the incidence of these complications was generally low. Further studies are still required to truly understand the risk/benefit associated with the use of IABP

    Primary Raynaud's phenomenon in an infant: a case report and review of literature

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    Raynaud's phenomenon (RP) is an extremely unusual finding in early infancy. In the present report we describe a one-month-old previously healthy male infant who presented with unilateral acrocyanosis. Although infantile acrocyanosis is known to be a benign and self-resolving condition, it is generally bilateral and symmetric. The unilateral nature of the acrocyanosis was an atypical finding in this infant. Consequently, he was closely monitored to evaluate the progression of his acrocyanosis. Based on his benign clinical course and failure to demonstrate other etiologies contributing to his acrocyanosis, he was diagnosed to have primary RP. Due to the rarity of RP in children, we review the progress in understanding the pathophysiology, epidemiology and management of RP and additionally discuss the differential diagnosis of unilateral and bilateral acrocyanosis in infants
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