790 research outputs found

    Dynamic behavior of NATM tunnel under harmonic loading

    Get PDF
    In modern societies, underground structures like subways, water transport and urban tunnels are using widely due to the rapid population growth and limitations of above ground spaces. Although these structures especially urban tunnels have been reported to experience less damages in comparison with above-ground structures during earthquakes, their damages have direct effects on human lives. In this study, 2D plane strain simulation of a NATM tunnel subjected to harmonic loading is employed to investigate the dynamic effects of the presence of tunnel on the ground responses and on the drift values of a tunnel section using advanced hardening soil constitutive model. The surface settlement, acceleration and drift in both tunnel section and free field are presented as time histories for different PGA and results have been discussed

    -

    Get PDF

    Diagnosis Performance of Cerebral Venous Thrombosis with Magnetic Resonance Imaging and Magnetic Resonance Venography in Zahedan (Southeast of Iran): A Series of 57 Patients

    Get PDF
    BACKGROUND: Cerebral venous sinus thrombosis (CVST) is a scarce disease with poor prognosis and its diagnosis often challenges physicians due to nonspecific symptoms and widespread clinical manifestations. AIM: To investigate the findings of magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) of patients with CVST diagnosis in Ali Ebne Abitaleb Hospital in Zahedan during 2013–2016 and to evaluate imaging pitfalls involving in late diagnosis, complications, and even death. METHODS: This retrospective descriptive study was done on 57 patients with confirmed CVST during 2013–2016 in Ali Ebne Abitaleb Hospital in Southeast of Iran (Zahedan). The MRI and MRV findings and related diagnostic pitfalls were evaluated. Twenty-one patients are pediatrics and 33 patients are adults. RESULTS: Of 57 patients, evidences of cerebral edema were found in 33 patients, among whom 2 patients showed parenchymal edema (cerebral edema) without infarction, and 31 patients exhibited parenchymal edema with infarction. The frequency of involvement in descending order was as followed; transverse sinus (96.49%), sigmoid sinus (49.12%), superior sagittal sinus (29.82%), jugular vein (19.29%), internal cerebral veins (7.01%), straight sinus (5.2%), and cortical veins (5.2%). Diagnostic pitfalls were also found in 8 patients. Seven patients exhibited acute and subacute thrombosis mimicked normal sinus flow void in T2-weighted images. No filling defect was seen on gadolinium-enhanced T1-weighted image in the other patient due to the sub-acute phase of thrombosis. CONCLUSION: The delayed diagnosis of CVST originating from nonspecific clinical features and diagnostic imaging pitfalls can result in poor outcomes in patients. To prevent the diagnostic pitfalls, the clinician should give a brief history and clinical data and radiologist(s) should interpret the findings in addition to the use of advanced MR sequences

    High-Methoxyl Apple Pectin Improves Rheological Properties and Storage Stability of the Flavored Probiotic Yogurt Drinks, Compared to Pomegranate Pectin

    Get PDF
    Background and Objective: Use of pectin has attracted interests in food and nutraceutical industries, owing to its positive effects on stability of dairy drinks and potential health benefits to humans. Furthermore, demands for the production of stable fermented milk drinks during storage period is high. Therefore, the aim of this study was to assess effects of apple and pomegranate pectins as stabilizers on various characteristics of probiotic yogurt drinks. Material and Methods: Apple and pomegranate pectins at concentrations of 0-0.5% (w v-1) were added to the probiotic yogurt drinks containing 2% of inulin and 12% of pomegranate juice. Then, rheological behavior, particle size distribution and stability of probiotic yogurt drinks were studied during storage. Results and Conclusion: Control (treatments with no pectin addition) and probiotic yogurt drinks containing pomegranate pectin (0.1-0.5%) showed Newtonian flow behavior and liquid-like behavior over the frequency range. Probiotic yogurt drinks with apple pectin included shear-thinning flow behavior, gel-like network at low frequencies and mean size particle of 50 mm. The highest G' and G" and stabilities during the storage were achieved in samples containing 0.5% of apple pectin. Results demonstrated that apple pectin included great potentials to be used in industrial production of probiotic yogurt drinks as it improved rheological properties and storage stability of the products. Therefore, use of 0.5% apple pectin is suggested in fermented milk drinks. Conflict of interest: The authors declare no conflict of interest

    The effect of size, morphology and surface properties of mesoporous silica nanoparticles on pharmacokinetic aspects and potential toxicity concerns

    Get PDF
    Mesoporous silica nanoparticles (MSNs) are considered as suitable delivery vehicles considering their unique characteristics. Various physicochemical characteristics of MSNs govern their pharmacokinetic parameters which affect the disposition of these nanoparticles in the body. Along with the advantages of MSNs, the toxicity of nanoparticles entering the body is a major concern. Various factors such as particle size, surface charge, route of administration, etc., may affect organ toxicity of MSNs. The main target organs involved in the metabolism and elimination of MSNs are the kidney and the liver as well as the hematopoietic system. In this review, we first introduced the physicochemical characteristics of MSNs which affect the pharmacokinetic properties including drug absorption and bio-distribution. Thereafter, we discussed the mechanisms by which organ toxicity may occur. In this regard, the effects of various factors on organ-based MSNs toxicities and molecular mechanisms have been summarized. At last, we emphasized on the role of the physicochemical parameters on organ-based toxicities, and the proposed approaches to prevent or at least diminish MSN-related toxicities are discussed in detail

    Differentiation between metastatic and tumour-free cervical lymph nodes in patients with papillary thyroid carcinoma by grey-scale sonographic texture analysis

    Get PDF
    Purpose: Papillary thyroid carcinoma (PTC) is the most common thyroid cancer, and cervical lymph nodes (LNs) are the most common extrathyroid metastatic involvement. Early detection and reliable diagnosis of LNs can lead to improved cure rates and management costs. This study explored the potential of texture analysis for texture-based classification of tumour-free and metastatic cervical LNs of PTC in ultrasound imaging. Material and methods: A total of 274 LNs (137 tumour-free and 137 metastatic) were explored using the texture analysis (TA) method. Up to 300 features were extracted for texture analysis in three normalisations (default, 3sigma, and 1-99%). Linear discriminant analysis was employed to transform raw data to lower-dimensional spaces and increase discriminative power. The features were classified by the first nearest neighbour classifier. Results: Normalisation reflected improvement on the performance of the classifier; hence, the features under 3sigma normalisation schemes through FFPA (fusion Fisher plus the probability of classification error [POE] + average correlation coefficients [ACC]) features indicated high performance in classifying tumour-free and metastatic LNs with a sensitivity of 99.27%, specificity of 98.54%, accuracy of 98.90%, positive predictive value of 98.55%, and negative predictive value of 99.26%. The area under the receiver operating characteristic curve was 0.996. Conclusions: TA was determined to be a reliable method with the potential for characterisation. This method can be applied by physicians to differentiate between tumour-free and metastatic LNs in patients with PTC in conventional ultrasound imaging

    The Safety and Effectiveness of a Polysaccharide Extracted from Rosa Canina in Patients with NAFLD: A Randomized Trial

    Get PDF
    Objective: Non-alcoholic fatty liver (NAFL) is a common pathology of hepatocytes due to the accumulation of fat which is predominantly implicated in obesity. Due to the multifaceted characterization of fatty liver and no effective treatment, this study was aimed to assess the protective effect of a polysaccharide in NAFL patients. Materials and methods: Polysaccharide fraction was isolated from Rosa canina and administered to 33 NAFL patients for 90 days. Demographic information, liver ultrasonography, and the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzymes were studied. Data were analyzed with the use of SPSS version 21 (SPSS, Inc.) All data were shown as means ± SDs and p < 0.05 was considered as significant. Results: After 90-day prescription, the weight loss, reduced activity of ALT and AST as well as changing the echogenicity of the liver from grades of 3, 2, and 1 to 2, 1 and normal, respectively, were observed in patients compared to the baseline (p ≤ 0.05). In addition, there were no visible side effects in patients during drug consumption. Conclusions: The data indicated that polysaccharide fraction with no obvious side effects is significantly able to protect the liver from steatosis in patients with NAFL disease. However, further information is required to better conclude on the effectiveness of the isolated polysaccharide as a promising fatty liver drug

    Geographical and climatic risk factors of cutaneous leishmaniasis in the hyper-endemic focus of Bam County in southeast Iran

    Get PDF
    IntroductionCutaneous leishmaniasis (CL) is a prevalent debilitating disease in many countries, particularly in Iran, the Middle East, North Africa, and South America. Bam County is the most important highly endemic focus of anthropometric CL in Iran and has been under consideration by WHO. This study investigated the environmental and geographic factors affecting the occurrence and distribution of CL in this focus.MethodsDemographic data and the home addresses of CL patients diagnosed from 2015 to 2020 were retrieved from the Leishmaniasis Center of Bam in southeast Iran. The effects of mean annual rainfall (MAR), mean annual humidity (MAH), mean annual temperature (MAT), maximum annual temperature (MaxMAT), minimum annual temperature (MinMAT), mean annual humidity (MAH), mean annual evaporation (MAE), mean annual frosty days (MAFD), mean annual snowy hours (MASH), elevation, and land cover on the distribution of CL were analyzed using geographical information systems (GIS) and univariate and multivariate regression models.ResultsOf 847 patients studied, 50.9% (n = 431) were female and 49.1% (n = 416) were male. The age classes 0–10 (n = 246) and 11–20 (n = 145) showed the highest frequency of patients, respectively. Leishmaniasis patients were reported from 66 villages/cities (11.8%) out of 561 residential areas in Bam County. Univariate analysis showed that urban settings (OR = 21.66), agriculture (OR = 5.73), orchards (OR = 5), salty land (OR = 1.05), and temperatures (OR = 2.37, 2.79 and 3.47) had positive effects on CL occurrence (p < 0.05), while altitude, precipitation, humidity, evaporation, and the number of frozen days had negative effects. Multivariate analysis identified urban settings (OR = 13.6), orchards (OR = 6.29), agriculture (OR = 5.82), and minimum temperature (OR = 2.38) as the most significant determinants of CL occurrence in this region.ConclusionEnvironmental and ecological factors play an important role in the distribution of CL in Bam County. The high-risk zones for CL are cities/large villages, agricultural and orchard areas in lower altitudes and with warmer climates and lower rainfall and humidity. This model can guide researchers and health managers to properly conduct CL control programs and allocate budgets

    COVID-19 Associated Mucormycosis::A Review of an Emergent Epidemic Fungal Infection in 3 Era of COVID-19 Pandemic

    Get PDF
    At a time when the COVID-19's second wave is still picking up in countries like India, a number of reports describe the potential association with a rise in the number of cases of mucormycosis, commonly known as the black fungus. This fungal infection has been around for centuries and affects those people whose immunity has been compromised due to severe health conditions. In this article, we provide a detailed overview of mucormycosis and discuss how COVID-19 could have caused a sudden spike in an otherwise rare disease in countries like India. The article discusses the various symptoms of the disease, class of people most vulnerable to this infection, preventive measures to avoid the disease, and various treatments that exist in clinical practice and research to manage the disease

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

    Full text link
    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis
    corecore