273 research outputs found

    Development of a non-iterative macromodeling technique by data integration and least square method

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    In this paper, a new method is introduced to synthesize the original data obtained from simulation or measurement results in the form of a rational function. The integration of the available data is vital to the performance of the proposed method. The values of poles and residues of the rational model are determined by solving the system of linear equations using conventional Least Square Method (LSM). To ensure the stability condition of the provided model, a controller coefficient is considered. Also, using this parameter, the designer can increase the stability margin of a system with poor stability conditions. The introduced method has the potential to be used for a wide range of practical applications since there is no specific restriction on the use of this method. The only requirement that should be considered is Dirichlet condition for the original data, usually the case for physical systems. To verify the performances of the proposed method, several application test cases were investigated and the obtained results were compared with those gathered by the well-known vector fitting algorithm. Also, the examinations showed that the method is efficient in the presence of noisy data

    Determinants of healthcare utilisation and predictors of outcome in colorectal cancer patients from Northern Iran

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    We aimed to assess healthcare utilisation (HU), its determinants, as well as its relationship with survival in colorectal cancer (CRC) patients. This study was conducted on incident CRC cases from Northern Iran. Information on HU was collected using a valid questionnaire, considering eight diagnostic and four therapeutic services. The results were categorised as good and poor HU. Multivariate logistic regression analysis was used to assess the relationship between HU and other variables. Cox regression analysis was performed to determine major predictors of survival. In total, 227 new cases of CRC were enrolled. HU could be assessed in 218 subjects (96). Living in rural areas was the strongest variable related to poor HU (adjusted OR, odds ratio=2.65; CI, confidence interval: 1.30-5.40). The median survival time was 40.5months. The 1-, 3- and 5-year survival rates were 71, 52 and 44 respectively. Cox regression analysis showed a significant lower survival rate in patients with poor HU (HR=2.3; CI: 1.46-3.64). HU was an independent predictor of survival in our CRC patients. Patients' place of residence was a significant determinant of HU. Regarding its effects on patients' outcome, HU and its determinants should be considered in designing CRC controlling programmes in our region and similar high-risk populations. © 2016 John Wiley & Sons Ltd

    Ruthenium-106 brachytherapy for thick uveal melanoma: Reappraisal of apex and base dose radiation and dose rate

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    Purpose: To evaluate the outcomes of ruthenium-106 (106Ru) brachytherapy in terms of radiation parameters in patients with thick uveal melanomas. Material and methods: Medical records of 51 patients with thick (thickness � 7 mm and < 11 mm) uveal melanoma treated with 106Ru brachytherapy during a ten-year period were reviewed. Radiation parameters, tumor regression, best corrected visual acuity (BCVA), and treatment-related complications were assessed. Results: Fifty one eyes of 51 consecutive patients including 25 men and 26 women with a mean age of 50.5 ± 15.2 years were enrolled. Patients were followed for 36.1 ± 26.5 months (mean ± SD). Mean radiation dose to tumor apex and to sclera were 71 (± 19.2) Gy and 1269 (± 168.2) Gy. Radiation dose rates to tumor apex and to sclera were 0.37 (± 0.14) Gy/h and 6.44 (± 1.50) Gy/h. Globe preservation was achieved in 82.4. Preoperative mean tumor thickness of 8.1 (± 0.9) mm decreased to 4.5 (± 1.6) mm, 3.4 (± 1.4) mm, and 3.0 (± 1.46) mm at 12, 24, and 48 months after brachytherapy (p = 0.03). Four eyes that did not show regression after 6 months of brachytherapy were enucleated. Secondary enucleation was performed in 5 eyes because of tumor recurrence or neovascular glaucoma. Tumor recurrence was evident in 6 (11.8) patients. Mean Log MAR (magnification requirement) visual acuity declined from 0.75 (± 0.63) to 0.94 (± 0.5) (p = 0.04). Best corrected visual acuity of 20/200 or worse was recorded in 37 of the patients at the time of diagnosis and 61.7 of the patients at last exam (p = 0.04). Non-proliferative and proliferative radiation-induced retinopathy was observed in 20 and 7 eyes. Conclusions: Thick uveal melanomas are amenable to 106Ru brachytherapy with less than recommended apex radiation dose and dose rates. © 2016, Termedia Publishing House Ltd. All rights reserved

    Scintigraphic evaluation of remote pre-conditioning protection against unilateral renal ischemia/reperfusion injury in rats: a longitudinal study

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    Purpose: To determine the role of remote perconditioning (RPeC) on renal function and histology in an animal model of unilateral renal ischemia and reperfusion (IR) injury. Methods: Rats were subjected to 60 min unilateral renal ischemia. RPeC protocol was the application of four cycles of 5 min IR of left femoral artery during renal ischemia. Assessments of histological changes and renal function were made 24 h, 1 week, or 3 weeks later. 99mTc-DMSA scan was performed using a small-animals SPECT system. Results: 24-h reperfusion decreased the 99mTc-DMSA uptake in the left kidney compared to the intact kidney of control animals. RPeC group has higher uptake compared to the IR group. After 1 week and 3 weeks, uptakes were gradually increased in both groups and no differences were observed. Severe morphological changes in the ischemic kidneys of both groups were observed after 24 h which attenuated after 1 week and 3 weeks. Moreover, no differences in creatinine and BUN levels between IR-treated and intact animals were observed. Conclusion: These data suggest that RPeC exerts a partially transient improvement in the renal function in the first day after reperfusion. However, long-term follow-up study showed no beneficial effects of RPeC. Moreover, noninvasive 99mTc-DMSA scan revealed a suitable tool in the follow-up evaluation of recovery process in the unilateral renal IR injury models

    Analgesic effects of intravenous ketamine during spinal anesthesia in pregnant women undergone Caesarean section; a randomized clinical trial

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    Suitable analgesia after cesarean section helps mothers to be more comfortable and increases their mobility and ability to take better care of their infants. Objectives: Pain relief properties of ketamine prescription were assessed in women with elective cesarean section who underwent spinal anesthesia with low dose intravenous ketamine and midazolam and intravenous midazolam alone. Patients and Methods: Sixty pregnant women scheduled for spinal anesthesia for cesarean section were randomized into two study groups. Ketamine (30 mg) + midazolam (1 mg = 2CC) or 1mg midazolam (2CC) alone, was given immediately after spinal anesthesia. Pain scores at first, second and third hours after CS operation, analgesic requirement and drug adverse effects were recorded in all patients. Results: Ketamine group had significant pain relief properties in compare with control group in first hours after cesarean section (0.78 ± 1.09 vs. 1.72 ± 1.22, VAS score, P = 0.00). Total dose of meperidine consumption in women of ketamine group was significantly lower than women of control group (54.17 ± 12.86 vs. 74.44 ± 33.82 mg, P = 0.02). There were no significant drug side effects in participated patients. Conclusions: Intravenous low-dose ketamine combined with midazolam for sedation during spinal anesthesia for elective Caesarean section provides more effective and long lasting pain relief than control group. © 2013 Iranian Society of Regional Anesthesia and Pain Medicine

    Molecular assay on Crimean Congo Hemorrhagic Fever virus in ticks (Ixodidae) collected from Kermanshah Province, Western Iran

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    Background: Crimean-Congo Hemorrhagic Fever (CCHF) is a feverous and hemorrhagic disease endemic in some parts of Iran and caused by an arbovirus related to Bunyaviridae family and Nairovirusgenus. The main virus reservoir in the nature is ticks, however small vertebrates and a wide range of domestic and wild animals are regarded as reservoir hosts. This study was conducted to determine the infection rate of CCHF virus in hard ticks of Sarpole- Zahab County, Kermanshah province, west of Iran. Methods: From total number of 851 collected ticks from 8 villages, 131 ticks were selected randomlyand investigated for detection of CCHF virus using RT-PCR. Results: The virus was found in 3.8 of the tested ticks. Hyalommaanatolicum, H.asiaticum and Rhipicephalus sanguineus species were found to have viral infection, with the highest infection rate (11.11) in Rh. sanguineus. Conclusion: These findings provide epidemiological evidence for planning control strategies of the disease in the study area

    Corneal Biomechanical Properties in Varying Severities of Myopia

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    Purpose: To investigate corneal biomechanical response parameters in varying degrees of myopia and their correlation with corneal geometrical parameters and axial length. Methods: In this prospective cross-sectional study, 172 eyes of 172 subjects, the severity degree of myopia was categorized into mild, moderate, severe, and extreme myopia. Cycloplegic refraction, corneal tomography using Pentacam HR, corneal biomechanical assessment using Corvis ST and Ocular Response Analyser (ORA), and ocular biometry using IOLMaster 700 were performed for all subjects. A general linear model was used to compare biomechanical parameters in various degrees of myopia, while central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were considered as covariates. Multiple linear regression was used to investigate the relationship between corneal biomechanical parameters with spherical equivalent (SE), axial length (AXL), bIOP, mean keratometry (Mean KR), and CCT. Results: Corneal biomechanical parameters assessed by Corvis ST that showed significant differences among the groups were second applanation length (AL2, p = 0.035), highest concavity radius (HCR, p < 0.001), deformation amplitude (DA, p < 0.001), peak distance (PD, p = 0.022), integrated inverse radius (IR, p < 0.001) and DA ratio (DAR, p = 0.004), while there were no significant differences in the means of pressure-derived parameters of ORA between groups. Multiple regression analysis showed all parameters of Corvis ST have significant relationships with level of myopia (SE, AXL, Mean KR), except AL1 and AL2. Significant biomechanical parameters showed progressive reduction in corneal stiffness with increasing myopia (either with greater negative SE or greater AXL), independent of IOP and CCT. Also, corneal hysteresis (CH) or ability to dissipate energy from the ORA decreased with increasing level of myopia. Conclusions: Dynamic corneal response assessed by Corvis ST shows evidence of biomechanical changes consistent with decreasing stiffness with increasing levels of myopia in multiple parameters. The strongest correlations were with highest concavity parameters where the sclera influence is maximal. © Copyright © 2021 Sedaghat, Momeni-Moghaddam, Azimi, Fakhimi, Ziaei, Danesh, Roberts, Monfared and Jamali

    Molecular mechanisms underlying curcumin-mediated microRNA regulation in carcinogenesis; Focused on gastrointestinal cancers

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    Curcumin is a bioactive ingredient found in the Rhizomes of Curcuma longa. Curcumin is well known for its chemopreventive and anti-cancer properties. Recent findings have demonstrated several pharmacological and biological impacts of curcumin, related to the control and the management of gastrointestinal cancers. Mechanistically, curcumin exerts its biological impacts via antioxidant and anti-inflammatory effects through the interaction with various transcription factors and signaling molecules. Moreover, epigenetic modulators such as microRNAs (miRNAs) have been revealed as novel targets of curcumin. Curcumin was discovered to regulate the expression of numerous pathogenic miRNAs in gastric, colorectal, esophageal and liver cancers. The present systematic review was performed to identify miRNAs that are modulated by curcumin in gastrointestinal cancers. © 202
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