222 research outputs found

    Appropriateness of referrals for single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) in a developing community: A comparison between 2005 and 2009 versions of ACCF/ASNC appropriateness criteria

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    Appropriateness of referrals for myocardial perfusion imaging (MPI) in developing countries has not been extensively studied. Our study was conducted to describe the ordering practices of physicians and appropriateness of MPI referrals in Iran. We prospectively applied 2005 and 2009 versions of the Appropriateness Use Criteria published by the American College of Cardiology Foundation (ACCF) and the American Society of Nuclear Cardiology (ASNC) to 291 consecutive patients (age 55.3 ± 10.3 years) who underwent SPECT-MPI. For this purpose, we convened a panel, consisting of two academic cardiologists, one academic clinician in internal medicine, and one academic clinician in nuclear medicine. The panelists were invited for a face-to-face meeting to judge appropriateness of SPECT-MPI and independently assign a specific indication (scenario), whenever possible, for each case in accordance with ACCF/ASNC appropriateness scenarios. Based on the 2005 ACCF/ASNC criteria, SPECT-MPI studies were judged appropriate for 211 (72.5%), uncertain for 36 (12.4%), inappropriate for 32 (11.0%), and unclassifiable for 12 (4.1%) referrals. The same figures based on the 2009 version were 219 (75.3%), 15 (5.2%), 49 (16.8%), and 8 (2.7%) patients, respectively. Overall agreement between the 2005 and 2009 versions was good (κ 0.63). Lack of chest pain and age below 60 years were significant indicators increasing the likelihood of inappropriate referrals by 2.9-3.4 fold. Absence of diabetes mellitus and hypertension, a normal lipid profile, lack of a past history of myocardial infarction or cardiovascular interventions (CABGs or PCI), as well as lack of application and exercise ECG stress test as the gate keeper (keeping abnormal ETT or inability of the patient to perform exercise as the appropriate indication for SPECT-MPI referral) were significant indicators, decreasing the odds of appropriate referrals. Generally a higher percentage of referrals with inappropriate indications had normal MPI. Our study provides an evidence for the fact that SPECT-MPI ordering practices in our developing community largely parallel the ACCF/ASNC recommendations. The implementation of appropriateness criteria is feasible in clinical settings and might provide an alternative to utilization management. © 2011 American Society of Nuclear Cardiology

    Numerical comparison on the efficiency of conventional and hybrid buckling-restrained braces for seismic protection of short-to-mid-rise steel buildings

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    Buckling-restrained brace (BRB) is a specific kind of bracing system which has an acceptable energy dissipation behavior in a way that would not be buckled in compression forces. However, considerable residual deformations are noticed in strong ground motions as a result of the low post-yield stiffness of the BRBs. The seismic performance of a modern lateral load resisting system, which is called the hybrid BRB, and its conventional counterpart are assessed and compared in this paper. Multiple plates with different stress–strain behavior are used in the core of this new innovative system, and this is its difference with the existent BRBs. Nonlinear static and incremental dynamic analyses are carried out for three building frames with different structural heights, which use conventional and hybrid BRB systems. To carry out response history analyses, the FEMA P695 far-field earthquake record set was adopted in different hazard levels. The hybrid BRBs are shown to have superior seismic performance in comparison with the conventional systems based on the response modification factor and the damage measures including residual displacements and inter-story drift ratios

    Ultrastructural and molecular characteristics of Setaria species based on sequence analysis of genomic and mitochondrial gene markers in cattle (Bos taurus) and buffaloes (Bubalus bubalis) from Iran

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    ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThe aim of the present study was to investigate the ultrastructural characteristics and genetic diversity of Setaria parasites from cattle (n=696) and buffalo (n= 522) from Khuzestan province of Iran and to compare them with available data from other countries/regions by sequences analysis of the 12S Rdna and the mitochondrial cytochrome C oxidase subunit I (cox1) genes. Based on SEM (Scanning Electron Micrographs) and light microscopy, all the isolated worms were identified as Setaria labiatopapillosa. Our results showed that 12.3% of cattle were infected with Setaria spp., while no infection was found in buffaloes. The maximal prevalence was observed in cattle younger than one year old. The prevalence rate was not influenced by the season of the year or gender. Comparison of the obtained sequences from Setaria with sequences of Setaria spp. from GenBank confirmed that all samples belong to the species S. labiatopapillosa. The phylogenetic tree constructed using cox1 and 12S rDNA genes of several other filarial nematodes showed that the Khuzestan isolates share a common branch with S. labiatopapillosa from other regions. Intra-specific variation was observed in 12S rDNA but not in cox1. In conclusion, our results indicating that S. labiatopapillosa is the main species involved in the spread of setarial infection in south-west of Iran and the identified worms corresponded mostly to worms that reported previously throughout other continents

    QuantiFERON-TB gold and tuberculin skin test for the diagnosis of latent tuberculosis infection in children

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    Background: Appropriate diagnosis and treatment of latent tuberculosis infection (LTBI) play the most important role in the control of tuberculosis. This study aimed to determine theprevalence of LTBI among healthy tuberculosis unexposed children vaccinated with BCG using the tuberculin skin test (TST) and QuantiFERON TB Gold In-Tube (QFT-GIT) and comparing the agreement between the two tests. Methods: A cross-sectional study was carried out between October 2009 and March 2010 in 24 schools and 11 daycare centers. A total of 967 children were divided into 15 age groups, with a minimum of 64 children per group. Results: The prevalence rates of LTBI with TST were 3.8, and 2.2 with QFT-GIT. One case was positive in TST and QFT-GIT, 20 cases were QFT-GIT positive, but TST negative and 36 cases were TST positive, but QFT-GIT negative, and finally, 910 cas eswere negative in both. There was poor agreement between TST and QFT-GIT (1.8, 95, CI: 0-5.3, k=0.007). The specificity of QFT-GIT in the BCG vaccinate, children aged 1-15 years old, was 97.8 (97.8, 95 CI: 96.8-98.8). After three months, 2/17 (11.8) of those initially QFT-GIT negative converted, and 10/15 (66) of those initially QFT-GITpositive reverted. Conclusion: It seems that TST and QFT-GIT are not appropriate tests for the diagnosis of LTBI among healthy tuberculosis unexposed BCG vaccinated children. There was a low reproducibility rate of QFT-GIT. The cause of the the poor agreement requires further studies. © 2015 Shiraz University of Medical Sciences. All rights reserved

    Comparative study of the effect of fuel deoxygenation and polar species removal on jet fuel surface deposition

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    The effect of near-complete deoxygenation and polar species removal on deposition propensity of a Jet A-1 fuel type, with marginal thermal oxidative stability was studied in a laboratory scale approach. The fuel deoxygenation was carried out via nitrogen purging and two types of bespoke zeolites were used separately in a packed bed reactor for partial polar separation. The treated fuel samples were assessed individually for deposition propensity, using “High Reynolds Thermal Stability(HiReTS)” test device. It was found that when the concentration of hydroperoxides in fuel is relatively high, polar removal is more effective way than the fuel deoxygenation in reducing carbona- ceous deposits. Furthermore, competitive adsorption of dissolved O 2 with polar species was studied for a model fuel doped with a few polar species, as well as for the Jet A-1 with marginal thermal stability, in the packed bed reactor with zeolite 3.7Å. The polar species added to the model fuel share the same functional groups as those in Jet A-1 with a strong im pact on fuel thermal degradation and surface deposition. These include hexanoic acids, heaxnol, hexanal, hexanone, phenyl amine (aniline), butylated hydroxytoluene(BHT), dibutyl disulfide and Fe naphthenate. A one-dimensional model for calculation of dissolved O 2 adsorption in the packed bed reactor was built using COMSOL Multiphysics. The modelling results were in good agreement with the induction period prior to the beginning of the O 2 adsorption, as well as the different stages of O 2 uptake during the competitive adsorption between dissolved O 2 and polar species in the Jet A-1 fuel. The calculation showed a discrep- ancy with the experimental results beyond the second phase of O 2 adsorption. More theories, assumptions and physical sub-models are required to build a more robust pre- dictive model. A new chemical reaction pathway based on the self-reaction of hydroperoxides was proposed as part of “Basic Autoxidation Scheme(BAS)” to justify the relatively high deposition propensity of the marginal fuel after near-complete deoxygenation. The vi- ability of this reaction pathway was supported by the quantum chemistry calculations

    Density Functional Theory calculations on copper-mediated peroxide decomposition reactions. Implications for jet fuel autoxidation

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    The presence of metal impurities in jet fuel can lead to a reduction in the thermal stability of the fuel. Density functional theory (DFT) calculations are reported on the reactions of hydroperoxides with both bare Cu(I) ions and Cu(naphthenate). The reaction of Cu(naphthenate) and cumene hydroperoxide forms one product complex. The release of alkoxy radicals (RO●) from the product complex is energetically feasible. This provides a low-energy route to radical formation when compared to hydroperoxide fission. The reaction mechanisms reported here for the copper-catalyzed hydroperoxide decomposition can be used to improve current chemical kinetic models for fuel autoxidation

    Effect of reactive sulfur removal by activated carbon on aviation fuel thermal stability

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    The effect of reactive sulfur removal from a Jet A-1 fuel with marginal thermal 3 stability on surface deposition propensity is reported. The sulfur removal was achieved 4 through adsorptive treatment the fuel with activated carbon.The treated fuel was as- 5 sessed for surface deposition propensity using a High Reynolds Thermal Stability(HiReTS)test 6 device. It was found that activated carbon has a strong adsorption capacity for removal 7 of reactive sulfur and Fe components from the fuel. This resulted in a substantial re- 8 duction of surface deposition propensity of the Jet A-1 fuel. 9 Density Functional Theory(DFT) was used to investigate the role of reactive sulfur and 10 Fe on thermal oxidative stability.Mechanistic pathways for intervention of these class 11 of species with hydroperoxides are proposed

    Technique and diagnostic utility of saline infusion sonohysterography

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    The introduction of saline infusion sonohysterography has significantly improved sonographic diagnosis of various endometrial pathologies. This procedure entails instillation of warm saline into the uterine cavity transcervically to provide enhanced visualization of the endometrium during transvaginal ultrasound examination. This article reviews the sonohysterography technique and current utility, as well as the spectrum of imaging features of various endometrial pathologies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135202/1/ijgo5.pd
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