655 research outputs found

    Magnetic Induction Tomography (MIT) simulation study for renal screening using different system frequencies and sizes of calcium oxalate

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    Nephrolithiasis is the process of forming stone in the kidney by crystallization. Due to the increasing prevalence of nephrolithiasis from time to time, medical institutions look for more advanced technology of medical imaging which can tackle the disadvantages of current medical imaging devices for renal, which are non-invasive, free radiation and rapid use. The research encompassed the design simulation study of Magnetic Induction Tomography (MIT) system for renal screening by using COMSOL multiphysics. MIT is a soft field tomography and a non-contact imaging modality used to image the passive electromagnetic properties (conductivity, permittivity and permeability) by applying principle of electromagnetic induction. In this research, 8 copper trans-receiver coils were employed in the MIT system and fixed by the insulation belt. Meanwhile, geometric set-up of renal organ imitates the transverse section at renal level of human body. Sensor performance analysis of MIT system was done based on various frequency and radius of calcium oxalate inside kidneys. In conclusion, frequency and radius of calcium oxalate affect the sensitivity performance of MIT system and has inverse relationship with sensitivity performance

    Evaluation of Test Characteristics for Outcome Measures Used in Raynaud's Phenomenon Clinical Trials

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    Objective Randomized controlled trials (RCTs) in Raynaud's phenomenon (RP) have shown conflicting efficacy data. Also, there is no consensus on the outcome measures that should be used. Our objectives were to assess the reliability of individual core set measures used in 3 RCTs, evaluate the placebo response for individual core set measures, and determine if a composite of individual core set measures will decrease the placebo response, which may improve our ability to see treatment effects in future trials. Methods We analyzed core set measures from 249 patients in the placebo‐treated groups from 3 RCTs. Core set measures analyzed included the Raynaud's Condition Score (RCS); patient and physician assessment of RP; pain, numbness, and tingling during an RP attack; average number of attacks/day; and duration of attacks. Intraclass correlation coefficients (ICCs) were calculated during the run‐in period to the RCTs. Results ICCs of ≄0.70 were observed for the RCS, attack symptoms, and average attacks/day. A high placebo response rate was observed for all individual core measures except the duration of attacks. For the RCS, the placebo response ranged from 56% with ≄10% improvement to 19.5% with ≄60% improvement. In contrast, placebo response rates of 10–20% were observed when several core set measures were combined to develop a composite score. Conclusion Outcome measures used in RCTs of RP are associated with marked variability. A combination of outcome measures is associated with low placebo responses. Future studies are needed to assess if a composite score will be able to differentiate placebo from an effective agent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97219/1/21858_ftp.pd

    A study of Magnetic Induction Tomography (MIT) for calcium oxalate renal screening

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    Nephrolithiasis is a process of stone formation in the kidney by crystallization. The increasing prevalence of nephrolithiasis from time to time had sought an alternative from the conventional imaging techniques that is invasive, radiative, and non-rapid usage. This paper enclosed a design simulation study of Magnetic Induction Tomography (MIT) system using COMSOL Multiphysics for renal imaging. MIT is a soft field tomography and non-contact imaging modality which can project the passive electromagnetic properties (conductivity, permittivity and permeability) under the principle of electromagnetic induction. In this research, 8 copper transreceiver coils were employed in the MIT system and fixed by the insulation belt. Meanwhile, geometric set-up of renal organ was set to imitate the transverse section of human renal. In the methodology, sensor performance analyses were done using frequency ranging from 50 kHz to 2 MHz of the MIT system on radii of calcium oxalate in renal. The sensor response and pattern are discussed in this paper

    Prenatal hypoxia induces increased cardiac contractility on a background of decreased capillary density.

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    Background: Chronic hypoxia in utero (CHU) is one of the most common insults to fetal development and may be associated with poor cardiac recovery from ischaemia-reperfusion injury,yet the effects on normal cardiac mechanical performance are poorly understood. Methods: Pregnant female wistar rats were exposed to hypoxia (12% oxygen, balance nitrogen)for days 10–20 of pregnancy. Pups were born into normal room air and weaned normally. At 10 weeks of age, hearts were excised under anaesthesia and underwent retrograde 'Langendorff' perfusion. Mechanical performance was measured at constant filling pressure (100 cm H2O) with intraventricular balloon. Left ventricular free wall was dissected away and capillary density estimated following alkaline phosphatase staining. Expression of SERCA2a and Nitric Oxide Synthases (NOS) proteins were estimated by immunoblotting. Results: CHU significantly increased body mass (P < 0.001) compared with age-matched control rats but was without effect on relative cardiac mass. For incremental increases in left ventricular balloon volume, diastolic pressure was preserved. However, systolic pressure was significantly greater following CHU for balloon volume = 50 ÎŒl (P < 0.01) and up to 200 ÎŒl (P < 0.05). For higher balloon volumes systolic pressure was not significantly different from control. Developed pressures were correspondingly increased relative to controls for balloon volumes up to 250 ÎŒl (P < 0.05).Left ventricular free wall capillary density was significantly decreased in both epicardium (18%; P <0.05) and endocardium (11%; P < 0.05) despite preserved coronary flow. Western blot analysis revealed no change to the expression of SERCA2a or nNOS but immuno-detectable eNOS protein was significantly decreased (P < 0.001) in cardiac tissue following chronic hypoxia in utero. Conclusion: These data offer potential mechanisms for poor recovery following ischaemia, including decreased coronary flow reserve and impaired angiogenesis with subsequent detrimental effects of post-natal cardiac performance

    Recognising and reacting to angry and happy facial expressions: a diffusion model analysis.

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    Researchers have reported two biases in how people recognise and respond to angry and happy facial expressions: (1) a gender-expression bias (Becker et al. in J Pers Soc Psychol, 92(2):179-190, https://doi.org/10.1037/0022-3514.92.2.179 , 2007)-faster identification of male faces as angry and female faces as happy and (2) an approach-avoidance bias-faster avoidance of people who appear angry and faster approach responses people who appear happy (Heuer et al. in Behav Res The, 45(12):2990-3001, https://doi.org/10.1016/j.brat.2007.08.010 2007; Marsh et al. in Emotion, 5(1), 119-124, https://doi.org/10.1037/1528-3542.5.1.119 , 2005; Rotteveel and Phaf in Emotion 4(2):156-172, https://doi.org/10.1037/1528-3542.4.2.156 , 2004). The aim of the current research is to gain insight into the nature of such biases by applying the drift diffusion model to the results of an approach-avoidance task. Sixty-five participants (33 female) identified faces as either happy or angry by pushing and pulling a joystick. In agreement with the original study of this effect (Solarz 1960) there were clear participant gender differences-both the approach avoidance and gender-expression biases were larger in magnitude for female compared to male participants. The diffusion model results extend recent research (Krypotos et al. in Cogn Emot 29(8):1424-1444, https://doi.org/10.1080/02699931.2014.985635 , 2015) by indicating that the gender-expression and approach-avoidance biases are mediated by separate cognitive processes
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