49 research outputs found

    Complete improvement in a patient with multiple irreversible defects of the left ventricle on 99m technetium-sestamibi SPECT after percutaneous coronary intervention.

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    99mTc-sestamibi has been investigated as a potential viability marker; initial studies have shown good concordance between 201Tl and 99mTc-sestamibi activities in both viable and nonviable myocardium. However, assessment of myocardial viability by 99mTc-sestamibi remains controversial for tissue recovery after revascularization. Here, we present a patient with several regions of severely diminished and irreversible (defect persisting in both early and delay images of each set scanning) defects on initial scan which were dissolved completely on the follow up scan after an intervention. In a 75 year-old Asian woman with acute myocardial infarction who received thrombolytic therapy and subjected to percutaneous coronary angiography (PCI) on day 28 after acute myocardial infarction(MI), resting 99mTc-sestamibi SPECT was applied on day 4 (initial scan) and 138 (follow up scan) after acute MI at 30 and 180 min after injection of tracer (740 MBq); Two-dimensional echocardiography was carried out at the same time. On the initial image set, there was irreversible defects in the apex, anteroapical, inferoapical, anteroseptal, septal and also anterior walls, while the follow up image was normal in all regions.The angiography intervention showed just significant stenosis on left anterior descending (LAD) vessel (95). This may highlight the failure of 99mTc-sestamibi as a marker of myocardial viability and also mandate further validating of the procedure with follow up scan or other modalities for myocardial viability investigation

    The Assessment of Quality and Modeling Educational Services In Payame Noor University

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    Abstract: One Of The Most Critical Steps Of  The Educational Planning Is The Evaluation Of Educational Goals.Identifying This Aim Requaires A Tool By Which To Measure The Quality Of  Programs.The Aim of This Study was  Assessment The Quality And Modeling Educational Services In Distance Education In Iran. The Method Of Research  Was Descriptive.In This Research, The Required Data Were Collected From A Sample Of 119 Consist Of  Male And Female Ph.D Student And Faculty Member Who Selected By Stratified  Sampling Method.The Formal Validity Of The Questionnaire Was Confirmed By The Specialists In The Field And The Reliability Was Calculated By K –Alfa At Laest (0.78).Data were Analized By Descriptive And Inferential (Factor Analysis) statistical Indexes. The Results Indicated That The Quality  Of Educational Services  Indexs In Curriculum Stractures,Student Services Are Average And The Faculty Member Support Is low And Weakness.In Addition,The Results Indicated That The 3 Factor Model With (RMSEA=0/085) And (CFI=0/97) Has Suitable Fitness

    Incorporating subject-specific geometry to compare metatarsal stress during running with different foot strike patterns

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    Stress fracture of the second metatarsal is a common and problematic injury for runners. The choice of foot strike pattern is known to affect external kinetics and kinematics but its effect on internal loading of the metatarsals is not well understood. Subject-specific models of the second metatarsal can be used to investigate internal loading in a non-invasive manner. This study aimed to compare second metatarsal stress between habitual rearfoot and non-rearfoot strikers during barefoot running, using a novel subject specific mathematical model, including accurate metatarsal geometry. Synchronised force and kinematic data were collected during barefoot overground running from 20 participants (12 rearfoot strikers). Stresses were calculated at the plantar and dorsal periphery of the midshaft of the metatarsal using a subject-specific beam theory model. Non-rearfoot strikers demonstrated greater external loading, bending moments and compressive forces than rearfoot strikers, but there were no differences in peak stresses between groups. Statistical parametric analysis revealed that non-rearfoot strikers had greater second metatarsal stresses during early stance but that there was no difference in peak stresses. This emphasises the importance of bone geometry when estimating bone stress and supports the suggestion that external forces should not be assumed to be representative of internal loading

    Candida interface keratitis after deep anterior lamellar keratoplasty: Clinical, microbiologic, histopathologic, and confocal microscopic reports

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    PURPOSE: To report the clinical, histopathologic, microbiologic, and confocal microscopic features of Candida keratitis after deep anterior lamellar keratoplasty (DALK). METHODS: We performed clinical, confocal scan, microbiologic and histopathologic examinations on two corneas from 2 young patients who underwent DALK for keratoconus. RESULTS: The first patient presented with asymptomatic white to cream-colored interface deposits 2 months after DALK. The confocal scan disclosed clusters of hyperreflective, fine granular deposits at the region of interface, with no evidence of inflammation or hyphaelike structures. The clinical presumption of possible "epithelial downgrowth" was suggested, and because of the progression of these lesions, irrigation of the interface was considered. Finally, penetrating keratoplasty was performed because of a rupture in the Descemet membrane. Histopathologic examination of the cornea disclosed yeastlike structures within the interface area. The microbiologic results of the irrigation fluid showed Candida glabrata. The second patient presented with a symptomatic infiltration of the inferior interface close to the suture site 2.5 months after DALK. The confocal scan showed foci of inflammation with clusters of hyperreflective round-shaped structures that resembled epithelial cells. Clinically, there was a suggestion of epithelial downgrowth, and subsequently, penetrating keratoplasty was performed because of the progression of the lesion. Histopathologic examination of the cornea disclosed an acute and chronic granulomatous keratitis caused by yeastlike structures. The microbiologic results revealed infection with Candida albicans. CONCLUSIONS: These are the first reported occurrences of interface Candida keratitis after DALK and with different confocal features. The clinical and the confocal features of interface Candida keratitis may be similar to those seen in epithelial downgrowth, which may postpone correct diagnosis and treatment. Candida keratitis should be considered in cases of interface deposits after any form of lamellar keratoplasty. © 2007 Lippincott Williams & Wilkins, Inc

    Performance evaluation and economic assessment of a gas power plant with solar and desalination integrated systems

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    In this study, a new configuration of a cogeneration system of electricity and freshwater in integration with solar collector has been thoroughly investigated. A gas power plant is modeled thermodynamically. The results of this modeling are compared with the actual data of a power plant to verify the simulation. Subsequently, by placing multi-effect desalination with thermal vapor compression and solar collectors, the functions including energy and exergy efficiencies and carbon dioxide emissions of the power plant have been studied. By applying the desalinating cycle and solar collectors, the energy efficiency of this power plant is increased from 35% to 46% and the exergy efficiency from 37% to 48%. This configuration of the cogeneration system with linear solar collectors produces 16.479 m3 of fresh water per day while reducing the CO2 emissions by 37,216 tons/d.http://www.deswater.comam2020Mechanical and Aeronautical Engineerin

    Sensitivity analysis of combined cycle parameters on exergy, economic, and environmental of a power plant

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    In this paper, a typical combined cycle power generation unit in Iran is simulated by a mathematical method in order to perform sensitivity analysis on environmental emission and electricity price. The results of this study demonstrate that the efficiency of the power plant depends on both gas turbine design parameters such as gas turbine inlet temperature, compressor pressure ratio and steam cycle design parameters such as HRSG pinch point temperature, condenser pressure. The results demonstrate that an increase in TIT and compressor pressure ratio have a significant effect on exergy efficiency and destruction.http://link.springer.com/journal/109732020-05-28hj2020Mechanical and Aeronautical Engineerin

    Baseline study in environmental risk assessment – Escalating need for computer models to be whole-system approach

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    Despite landfills having the potential to pollute the environment both during their operation and long after they have ceased to receive waste, they remain a dominant waste management option, particularly in the UK. In order to combat the environmental pollution caused by landfills, risk analysis is increasingly being employed through computer models. However, for a risk analysis process to be successful, its foundation has to be well established through a baseline study. This paper aims to identify knowledge gaps in software packages regarding environmental risk assessments in general, and especially those that have been developed specifically for landfills and landfill leachate. The research establishes that there is no holistic computer model for the baseline study of landfills, which risk assessors can use to conduct risk analyses specifically for landfill leachate. This paper also describes a number of factors and features that should be added to the baseline study system in order to render it more integrated – thereby enhancing quantitative risk analysis, and subsequently environmental risk management

    Scintigraphic parameters with emphasis on perfusion appraisal in rest 99mTc-sestamibi SPECT in the recovery of myocardial function after thrombolytic therapy in patients with ST elevation myocardial infarction (STEMI)

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    Introduction: This study was performed to determine the clinical application of rest 99mTc-sestamibi in the assessment of viability and functional improvement of the left ventricle (LV) myocardium in the post-thrombolytic therapy of acute myocardial infarction (AMI). Material and methods: In 37 patients with AMI who received thrombolytic therapy, 2-dimensional (2D) echocardiography, as well as the resting redistribution of 99mTc-sestamibi, was investigated, both within 1 week and 3-5 months after AMI. The predictive capacity of the perfusion percentage for myocardial function recovery was evaluated. Also, the capacities of the possible variables in the prediction of recovery of myocardial function resulting from a change in LV ejection fraction (EF) were evaluated using stepwise multiple regression analysis. Results: Thirty-seven patients (30 men and 7 women; mean age: 58±14 years) with AMI were enrolled in the study. Redistribution was observed in 35 and 50 segments of the initial and follow-up scans, respectively. In addition, 146 segments with reverse redistribution (RR), both in the initial scan (118 segments) and the follow-up scan (86 segments), were also observed. An apparent difference in wall motion scores was seen between the initial and follow-up echocardiographs (p<0.001). Furthermore, using the optimal cut-off point of perfusion percentage in each image set, sensitivity as well as specificity and likelihood ratio (LR) for the improvement of regional wall motion after 3-5 months were defined. Conclusion: These data showed that redistribution and reverse redistribution of 99mTc-sestamibi post thrombolytic therapy can be used as a marker of viability to predict the recovery of segmental wall motion abnormality (stunning), as well as the improvement of segmental perfusion uptake. This study also demonstrates that the resting 99mTc-sestamibi SPECT can be used for an approximate assessment of LV function status and can predict the recovery of jeopardized myocardium function after thrombolytic therapy. © 2011 SAGE Publications

    Three methods for correction of astigmatism during phacoemulsification

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    Purpose: To compare the safety and efficacy of three methods for correcting pre-existing astigmatism during phacoemulsification. Methods: This prospective, comparative, non-randomized study was conducted from March 2010 to January 2011, and included patients with keratometric astigmatism �1.25 D undergoing cataract surgery. Astigmatism was corrected using the following approaches: limbal relaxing incisions (LRI) on the steep meridian, extension and suturing of the phaco incision created at the steep meridian (extended-on-axis incision, EOAI), and toric intraocular lens (tIOL) implantation. Keratometric and refractive astigmatism were evaluated 1, 8, and 24 weeks postoperatively. Results: Eighty-three eyes of 72 patients (35 male and 37 female) with mean age of 62.4 ± 14.3 (range, 41-86) years were enrolled. The astigmatism was corrected by using the LRI, EOAI and tIOL implantation methods in 17, 33 and 33 eyes, respectively. Postoperative uncorrected distance visual acuity (UDVA) was significantly improved in all three groups. The difference in postoperative UDVA was not statistically significant among the study groups throughout follow-up except at week 24, when UCVA was significantly better in the tIOL group as compared to the EOAI group (P = 0.024). There is no statistically significant difference of correction index and index of success between three groups at week 24 (P = 0.085 and P = 0.085 respectively). Conclusion: There was no significant difference in astigmatism reduction among the three methods of astigmatism correction during phacoemulsification. Each of these methods can be used at the discretion of the surgeon. © 2016 Journal of Ophthalmic and Vision Research

    Simulated Optimisation of Disordered Structures with negative Poisson’s ratios

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    Copyright © 2009 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Mechanics of Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Mechanics of Materials, Vol. 41 Issue 8 (2009). DOI: 10.1016/j.mechmat.2009.04.008Two-dimensional regular theoretical units that give a negative Poisson’s ratio (NPR) are well documented and well understood. Predicted mechanical properties resulting from these models are reasonably accurate in two dimensions but fall down when used for heterogeneous real-world materials. Manufacturing processes are seldom perfect and some measure of heterogeneity is therefore required to account for the deviations from the regular unit cells in this real-life situation. Analysis of heterogeneous materials in three dimensions is a formidable problem; we must first understand heterogeneity in two dimensions. This paper approaches the problem of finding a link between heterogeneous networks and its material properties from a new angle. Existing optimisation tools are used to create random two-dimensional topologies that display NPR, and the disorder in the structure and its relationship with NPR is investigated
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