44 research outputs found

    Diagnostic Accuracy of Ultrasonography and Radiography in Detection of Pulmonary Contusion; a Systematic Review and Meta-Analysis

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    Introduction: Ultrasonography is currently being used as one of the diagnostic modalities in various medical emergencies for screening of trauma patients. The diagnostic value of this modality in detection of traumatic chest injuries has been evaluated by several studies but its diagnostic accuracy in diagnosis of pulmonary contusion is a matter of discussion. Therefore, the present study aimed to determine the diagnostic accuracy of ultrasonography and radiography in detection of pulmonary contusion through a systematic review and meta-analysis. Methods: An extended systematic search was performed by two reviewers in databases of Medline, EMBASE, ISI Web of Knowledge, Scopus, Cochrane Library, and ProQuest. They extracted the data and assessed the quality of the studies. After summarization of data into true positive, false positive, true negative, and false negative meta-analysis was carried out via a mixed-effects binary regression model. Further subgroup analysis was performed due to a significant heterogeneity between the studies. Results: 12 studies were included in this meta-analysis (1681 chest trauma patients, 76% male). Pooled sensitivity of ultrasonography in detection of pulmonary contusion was 0.92 (95% CI: 0.81-0.96; I2= 95.81, p<0.001) and its pooled specificity was calculated to be 0.89 (95% CI: 0.85-0.93; I2 = 67.29, p<0.001) while these figures for chest radiography were 0.44 (95% CI: 0.32-0.58; I2= 87.52, p<0.001) and 0.98 (95% CI: 0.88-1.0; I2= 95.22, p<0.001), respectively. Subgroup analysis showed that the sources of heterogeneity between the studies were sampling method, operator, frequency of the transducer, and sample size. Conclusion: Ultrasonography was found to be a better screening tool in detection of pulmonary contusion. Moreover, an ultrasonography performed by a radiologist / intensivist with 1-5MHz probe has a higher diagnostic value in identifying pulmonary contusions

    Torsional wave propagation in solar tornadoes

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    Aims. We investigate the propagation of torsional waves in coronal structures together with their collimation effects in the context of magnetohydrodynamic (MHD) theory. The interplay of the equilibrium twist and rotation of the structure, e.g. jet or tornado, together with the density contrast of its internal and external media is studied to shed light on the nature of torsional waves. Methods. We consider a rotating magnetic cylinder embedded in a plasma with a straight magnetic field. This resembles a solar tornado. In order to express the dispersion relations and phase speeds of the axisymmetric magnetohydrodynamic waves, the second-order thin flux tube approximation is implemented for the internal medium and the ideal MHD equations are implemented for the external medium. Results. The explicit expressions for the phase speed of the torsional wave show the modification of the torsional wave speed due to the equilibrium twist, rotation, and density contrast of the tornado. The speeds could be either sub-Alfvénic or ultra-Alfvénic depending on whether the equilibrium twist or rotation is dominant. The equilibrium twist increases the phase speed while the equilibrium rotation decreases it. The good agreement between the explicit versions for the phase speed and that obtained numerically proves adequate for the robustness of the model and method. The density ratio of the internal and external media also play a significant role in the speed and dispersion. Conclusions. The dispersion of the torsional wave is an indication of the compressibility of the oscillations. When the cylinder is rotating or twisted, in contrast to when it only possesses a straight magnetic field, the torsional wave is a collective mode. In this case its phase speed is determined by the Alfvén waves inside and outside the tornado

    IMECE2008-68607 A REFINED ANALYTICAL COMBUSTION MODEL FOR EVALUATING THE EFFECTS OF EGR PERCENTAGE ON IMPROVEMENT OF KNOCK CHARACTERISTICS OF NATURAL GAS IN SPARK IGNITION ENGINE

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    ABSTRACT Accurate modeling of engine knock onset is needed for control of SI engine combustion and increase of thermal efficiency. This contribution presents a refined model for analysis of engine knock when using natural gas fuel and EGR. The model is used to compare the effectiveness of EGR to other knock suppression methods such as lean-burn combustion, compression ratio reduction, and ignition timing retardation. The model consists of two zones: a burned combustion products region and an unburned reactants comprising the end gas region, separated by a flame front of negligible thickness. A mass burning rate is derived from a turbulent combustion model. FORTRAN code as programming software is used for combustion simulation. Operating conditions which affect an engine's tendency to knock are discussed. The model was validated by comparison to experimental data. Results show that EGR addition is more effective at suppressing knock, while maintaining high thermal efficiency and output work, compared to other knock suppression techniques such as inlet pressure and temperature, equivalence ratio, spark timing, or compression ratio

    Evaluation of Physiological Indices of Tomato (Solanum lycopersicum) Plant Under Different Irrigation Intervals and Superabsorbent Polymer A200

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    Water deficiency stress as the most important abiotic stress plays an important role in the yield suppression of plants worldwide. Considering physiological indices to improve drought resistance is of paramount importance. The objective of present study was to evaluate the effects of different irrigation intervals (irrigation after 5, 7, 9 and 11 days) and rates of superabsorbent polymer (Nil, 0.2, 0.3, 0.4 and 0.5 percent of pot medium weight) on some physiological parameters of tomato (Solanum lycopersicum) plant under greenhouse condition. The study carried out at College of Agriculture, Ilam University during 2009-2010 using a factorial layout in randomized complete blocks design (RCBD) with three replications. Statistical analysis showed significant effects of the irrigation and superabsorbent polymer on total yield and plant physiological parameters including leaf relative water content (RWC), water use efficiency (WUE), total soluble solids (TSS), chlorophyll, proline and malondialdehyde (MDA) content. In drought conditions total yield, RWC, WUE and chlorophyll a reduced but MDA accumulation, proline content and TSS increased. Application of superabsorbent polymer significantly caused increasing of total yield, RWC, WUE, chlorophyll a and decreasing of MDA content, proline and TSS. Our results showed that superabsorbent polymers can absorb and retain extremely large amounts of water and decreased adverse effects of drought stress on the plants

    Sex Difference in Trigeminal Neuropathic Pain Response to Exercise: Role of Oxidative Stress

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    Aim. Orofacial chronic neuropathic pain commonly occurs following trigeminal nerve injuries. We investigated whether swimming exercise can reduce trigeminal neuropathic pain through improving antioxidant capacity. Materials and Methods. Twenty-eight Wistar rats of either sex and 180–220 grams were divided into 4 groups as sham, neuropathy, neuropathy + single bout exercise, and neuropathy + 2 weeks of exercise. Trigeminal neuropathy was carried out through chronic constriction injury (CCI) of infraorbital nerve. Protocols of exercise were included a single bout session (45 minutes) and a 2-week (45 minutes/day/6 days a week) swimming exercise. Mechanical allodynia was detected using Von Frey filaments. The activity of the serum antioxidant enzymes glutathione peroxidase and superoxides dismutase was assayed using ELISA kits. Results. We found that CCI significantly reduced facial pain threshold in both sexes (P<0.05). Both swimming exercise protocols significantly reduced mechanical allodynia in female rats compared to the sham group; however, only 2 weeks of exercise were significantly effective in male rats. The activity of antioxidant enzyme glutathione peroxidase significantly (P<0.05) decreased following CCI in female rats against that in the sham group and 2-week exercise significantly (P<0.05) increased it toward the control level. The levels of glutathione peroxidase in male rats and superoxidase dismutase in both sexes were not significantly different compared to their sham groups. Conclusion. Swimming exercise alleviates trigeminal neuropathic pain in both sexes. Oxidative stress as a possible mechanism was involved in the effect of exercise on female rat trigeminal neuropathy

    Effect of intraperitoneal bupivacaine on postoperative pain in laparoscopic bariatric surgeries

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    Background: Postoperative pain has many adverse effects and, if not properly controlled, it may lead to a wide range of complications. Opioids, as frequently used drugs for pain control, have some serious respiratory and gastrointestinal complications, especially in obese patients. Objectives: In this study, we planned to evaluate the effect of intraperitoneal bupivacaine lavage on postoperative pain in laparoscopic bariatric surgeries. Setting: The study was conducted in Firoozgar Hospital (affiliated to Iran University of Medical Sciences), Tehran, Iran. Methods: In this clinical trial, 106 patients scheduled for laparoscopic bariatric surgery, randomly assigned to receive either intraperitoneal lavage with 50 mL of .2 bupivacaine or the same volume of normal saline during the operation. One-gram intravenous paracetamol was infused for all patients at the end of surgery, and all patients received intravenous paracetamol infusion for 1 day after surgery. Pain level, assessed by visual analog scale, was recorded at 1, 4, 8, and 24 hours after surgery. Total additive analgesics administered during the first day after surgery was also recorded. Results: The pain score during the first 24 hours after surgery decreased significantly in both groups, but comparing the groups showed that pain level at 1, 4, 8, and 24 hours after surgery in the bupivacaine group was significantly lower than the normal saline group (P < .05). Also, opioid consumption during 24 hours was significantly lower in the bupivacaine group (P < .001). Conclusions: Intraperitoneal lavage with bupivacaine is an effective approach to control postoperative pain in obese patients undergoing laparoscopic bariatric surgery. © 2019 American Society for Bariatric Surger

    Synthesis of immobilised Ni-doped TiO2 nanoparticles through hydrothermal route and their efficiency evaluation in photodegradation of formaldehyde

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    The aim of the present study was to synthesis Ni-doped TiO2 nanoparticles (NPs) in order to evaluate their effectiveness in photocatalytic degradation of formaldehyde in the aqueous phase. The Ni-doped TiO2 NPs were synthesised using a mild hydrothermal method. They were then immobilized on glass plates by the calcination method. Characterisation of Ni-doped TiO2 NPs was also carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The SEM images showed the uniform distribution of assynthesised NPs on the surface of glass plates, with multidimensional crystalline structures. The results indicated that increasing the dopant weight ratio to 0.7% enhanced the photocatalytic degradation efficiency of formaldehyde; however, a further increase in the dopant weight ratio reduced the process efficacy. According to the results, increasing the initial pH from acidic and neutral to alkaline conditions decreased the efficacy of the process. Furthermore, the results showed that increasing the amount of nanocatalyst and decreasing the initial concentration of formaldehyde favoured the photocatalytic degradation of formaldehyde

    Albumin utilization evaluation in a major teaching hospital in Iran: Recommendations for guideline development

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    Objective: Human albumin solution is an expensive colloidal preparation which is commonly used in clinical practice. Due to high cost of albumin, increased rate of the inappropriate use worldwide, and many other reasons, it is imperative to establish a practical protocol to use albumin products and limit its usage. The aim of this study was to identify albumin utilization patterns in a teaching hospital and to demonstrate the importance of the need to reconsider prescribing strategies for albumin administration. Methods: This retrospective cross-sectional study was performed between August 2016 and December 2016 at Firoozgar Hospital affiliated to Iran University of Medical Sciences, Tehran, Iran. All albumin prescriptions for adult patients during the study period were enrolled for appropriateness evaluation according to the latest evidence-based studies and guidelines. Findings: Among 320 albumin prescriptions, 168 (52.5%) were inappropriate according to the current evidence. The most common irrational causes for the albumin usage were hypoalbuminemia (23.4%), nutritional support (13.7%), neuroprotection in subarachnoid hemorrhage (3%), pretreatment for cancer surgery (2.8%), edema (1.6%), hepatic failure (1.6%), and paracentesis (3%). The total amount of albumin used for 320 patients was 52,050 g, from which 28,470 g was inappropriate resulting in $97,398 wastage. Conclusion: These findings, along with aforementioned guidelines, support the requirement for physicians' educational programs and proper strategies for appropriate prescriptions and could also be important in modifying the available guidelines concerning expensive drugs such as albumin

    A comparative optimization and performance analysis of four different electrocoagulation-flotation processes for humic acid removal from aqueous solutions

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    Humic substances (HSs) are a group of complex macromolecular polymeric compounds originating from the decomposition of plant residuals and other organic matter. Within the presence of micro-pollutants and heavy metals, HSs negatively act upon potable water quality by contributing to aesthetic problems such as yellowish or brownish color and annoying taste and odor. They are also responsible for re-growth of pathogenic microorganisms and fouling of membranes in water distribution systems. More importantly, these high-molecular-weight polymers have been noted to be the major contributor to the formation of disinfection by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). Considering these harmful effects, removal of HSs is one of the significant tasks in drinking water treatment. For this purpose, this study aimed to explore the effects of various operating parameters (initial concentration, initial pH, electrical conductivity, pulse time, pulse number, and process time) on the humic acid (HA) removal efficiency and energy consumption. In this study, a new current supply method called alternating pulse current electrocoagulation-flotation (APC-ECF) process was proposed, and a detailed comparative optimization of four different ECF processes (direct current (DC)-simple electrode, DC-perforated electrode, pulse current-simple electrode, and pulse current-perforated electrode) was conducted within the framework of Taguchi-based experimental design methodology. According to scanning electron microscopy (SEM), the morphology of electrode surfaces with APC and perforated electrode showed less disordered (irregular) pores and a regular structure of aluminum compared to the DC, which confirmed the difference in the corrosion rates. Moreover, the proposed APC-ECF method led to the production of less dewatered and dense sludge. The results of the performance analysis revealed that the APC with a perforated electrode provided 3.2-fold lower energy consumption and 2.5-fold lower aluminum consumption compared to the DC with a simple electrode. Considering the expenses associated with power consumption and sludge disposal costs for the electrocoagulation unit,the experimental findings corroborated that the proposed APC-ECF process could be used as a promising and cost-effective technology in water treatment for the removal of HSs
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