166 research outputs found

    Origin of the Significant Impact of Ta on the Creep Resistance of FeCrNi Alloys

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    Heat resistant FeCrNi alloys are widely used in the petrochemical industry because they exhibit a unique combination of creep and oxidation resistance at temperatures exceeding 900^\circC. Their creep properties are often optimized by micro-additions of carbide forming elements. In the present work, the influence of Ta micro-additions has been experimentally investigated both on as-cast and aged microstructures to understand the origin of the significant impact of this element on the creep resistance. Calculations with thermocal software were also carried out to support experimental data. It is shown that a small addition of Ta is beneficial as it increases the volume fraction of stable MC carbides. We demonstrate also that additions of Ta may have a dramatic effect on the thermal stability of microstructures. This is attributed to a smaller equilibrium volume fraction of M23C6 and more pronounced heterogeneous precipitation at MC/matrix interfaces. The influence on the creep properties in then discussed

    New Approaches to Analyze Gasoline Rationing

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    In this paper, the relation among factors in the road transportation sector from March, 2005 to March, 2011 is analyzed. Most of the previous studies have economical point of view on gasoline consumption. Here, a new approach is proposed in which different data mining techniques are used to extract meaningful relations between the aforementioned factors. The main and dependent factor is gasoline consumption. First, the data gathered from different organizations is analyzed by feature selection algorithm to investigate how many of these independent factors have influential effect on the dependent factor. A few of these factors were determined as unimportant and were deleted from the analysis. Two association rule mining algorithms, Apriori and Carma are used to analyze these data. These data which are continuous cannot be handled by these two algorithms. Therefore, the two-step clustering algorithm is used to discretize the data. Association rule mining analysis shows that fewer vehicles, gasoline rationing, and high taxi trips are the main factors that caused low gasoline consumption. Carma results show that the number of taxi trips increase after gasoline rationing. Results also showed that Carma can reach all rules that are achieved by Apriori algorithm. Finaly it showed that association rule mining algorithm results are more informative than statistical correlation analysis

    Genotyping of acanthamoeba in rural drinking water sources in Kashan and Aran-Bidgol, Iran

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    Background and purpose: Acanthamoeba spp. are an opportunistic protozoan in environmental sources that can cause respiratory infection and keratitis. The present study was conducted to determine the prevalence and genotypes of Acanthamoeba in rural drinking water sources in Kashan and Aran- Bidgol, Iran. Materials and methods: In this study, 162 samples from 54 drinking water sources were collected in 2017. After samples filtration, they were cultured on non-nutrient agar to isolate free-living amoeba. After DNA extraction, the Polymerase Chain Reaction using JDP1, JDP2 primers was performed to detect Acanthamoeba spp. and finally the genotype of eight isolates was determined. Data analysis was done in SPSS applying Chi-square and Fisher�s exact test. Results: Among the samples 35.2 were found to be contaminated with free-living amoeba, among which 19 isolates (11.7) were confirmed as Acanthamoeba. The rates of free-living amoeba and Acanthamoba were 35.4 and 11.8, respectively, in Kashan, which were higher than those in Aran- Bidgol. Frequency of free-living amoeba in Qanat, well, and spring was 55.6, 30.2, and 26.7, respectively. Acanthamoeba contamination rates were 13.9, 11.5 and 10, respectively. Acanthamoeba contamination rate was higher in surface wells than that in deep wells. The genotype of all Acanthamoeba isolates belonged to T4. Conclusion: This study revealed that drinking water sources were contaminated with free-living amoeba and Acanthamoeba. All isolates were T4 genotype, therefore, these sources could be considered as a risk factor for public health. © 2018, Mazandaran University of Medical Sciences. All rights reserved

    Optimal Scheduling of Multiproduct Pipeline System Using MILP Continuous Approach

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    Part 5: Planning and Scheduling; International audience; To date, the multiproduct pipeline transportation mode has nationally and internationally considerably evolved thanks to his efficiently and effectively of transporting several products. In this paper, we focus our study on the scheduling of a multiproduct pipeline system that receives a number of petroleum products (fuels) from a single refinery source in order to be distributed to several storage and distribution centers (depots). Mixed Integer Linear Programming (MILP) continuous mathematical approach is presented to solve this problem. The sequence of injected products in the same pipeline should be carefully studied, in order to meet market demands and ensure storage autonomy of the marketable pure products in the fuels depots on the one hand and to minimize the number of interfaces; Birth zone of mixture between two products in contact and in sequential flow, which may hinder the continuous operation of the pipeline system, by the necessity of additional storage capacity for this last mixture, that is in no way marketable and requires special processing operations. This work is applied on a real case of a multiproduct pipeline that feeds the western and southwestern region of Algeria with fuels. The obtained results based on the MILP continuous approach give an optimal scheduling of the multiproduct transport system with a minimized number of interfaces. Document type: Conference objec

    Seroepidemiology of hepatitis E virus infection in patients undergoing maintenance hemodialysis: Systematic review and meta-analysis

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    Patients undergoing regular hemodialysis (HD) are at an extreme risk of acquiring bloodstream infections compared to the general population. Hepatitis E virus (HEV) infection is an important emerging health issue in these patients. To date, numerous studies have investigated the seroprevalence of HEV among HD patients across the world; however, the data are conflicting. The present study aimed to measure the exposure rate of HD patients to HEV infection by estimating the overall seroprevalence of HEV in this high-risk group. A systematic literature search was carried out using five electronic databases from inception to January 10, 2020, with standard keywords. Pooled seroprevalence estimates with 95 confidence intervals (CIs) were calculated using a random intercept logistic regression model. The seroprevalence of HEV increased from 6.6 between the years of 1994 and 2000 to 11.13 from 2016 to 2020. Blood transfusion was associated with a nearly 2-fold increase in the rate of HEV seropositivity (OR = 1.99; 95 CI: 1.50-2.63, P <.0001, I2 = 6.5). HEV seroprevalence among patients with HD for more than 60 months was significantly higher than those with HD for less than 60 months (27.69, 95 CI: 20.69-35.99 vs 15.78, 95CI: 8.85-26.57, respectively) (P =.06). Our results indicated increased exposure of HD patients with HEV infection over the last decade. We concluded that blood transfusion and duration of HD are considerable risk factors for acquiring HEV infection among HD patients. © 2020 International Society for Apheresis, Japanese Society for Apheresis, and Japanese Society for Dialysis Therap

    The association of bone, fingernail and blood manganese with cognitive and olfactory function in Chinese workers

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    Occupational manganese (Mn) exposure has been associated with cognitive and olfactory dysfunction; however, few studies have incorporated cumulative biomarkers of Mn exposure such as bone Mn (BnMn). Our goal was to assess the cross-sectional association between BnMn, blood Mn (BMn), and fingernail Mn (FMn) with cognitive and olfactory function among Mn-exposed workers. A transportable in vivo neutron activation analysis (IVNAA) system was designed and utilized to assess BnMn among 60 Chinese workers. BMn and FMn were measured using inductively coupled plasma mass spectrometry. Cognitive and olfactory function was assessed using Animal and Fruit Naming tests, World Health Organization/University of California-Los Angeles Auditory Verbal Learning Test (AVLT) and the University of Pennsylvania Smell Identification Test (UPSIT). Additional data were obtained via questionnaire. Regression models adjusted for age, education, factory of employment, and smoking status (UPSIT only), were used to assess the relationship between Mn biomarkers and test scores. In adjusted models, increasing BnMn was significantly associated with decreased performance on average AVLT scores [β (95% confidence interval (CI)) = -0.65 (-1.21, -0.09)] and Animal Naming scores [β (95% CI) = -1.54 (-3.00, -0.07)]. Increasing FMn was significantly associated with reduced performance measured by the average AVLT [β (95% CI) = -0.35 (-0.70, -0.006)] and the difference in AVLT scores [β (95% CI) = -0.40 (-0.77, -0.03)]. BMn was not significantly associated with any test scores; no significant associations were observed with Fruit Naming or UPSIT tests. BnMn and FMn, but not BMn, are associated with cognitive function in Mn-exposed workers. None of th

    Human papilloma virus and breast cancer: The role of inflammation and viral expressed proteins

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    Background: Breast cancer is currently the most common neoplasm diagnosed in women globally. There is a growing body of evidence to suggest that human papillomavirus (HPV) infection may play a key role in invasiveness of breast cancer. The aim of this study was to determine the presence of HPV in patients with breast cancer and its possible association with cancer progression. Methods: Breast specimens were collected from 72 patients with breast cancer and 31 healthy controls. The presence of HPV was investigated by polymerase chain reaction (PCR) and genotyping was performed for positive cases. We also evaluated the viral factors such as E6, E2, and E7 in HPV positive cases. Enzyme-linked immunosorbent assay (ELISA (and Real-time PCR techniques were used to measure the expression level of anti-carcinogenic genes, such as p53, retinoblastoma (RB), breast and ovarian cancer susceptibility gene (BRCA1, BRCA2) and inflammatory cytokines, including tumor necrosis factor α (TNF-α), transforming growth factor β (TGF-β), nuclear factor-kB (NF-kB), and different interleukins [ILs] (IL-1,IL6, and IL-17). Results: The HPV DNA was detected in 48.6% of breast cancer samples, whereas only 16.1% of controls were positive for HPV. We observed statistically significant differences between breast cancer patients and HPV presence (P = 0.003). HPV type 18 was the most prevalent virus genotype in patients. The expression of P53, RB, BRCA1, and BRCA2 were decreased in patients with HPV-positive breast cancer as compared to HPV-negative breast cancer and healthy controls. (All P-values were less than 0.05). The presence of the HPV was associated with increased inflammatory cytokines (IL-1, IL-6, IL-17, TGF-β, TNF-α, and NF-kB) and tumor progression. Conclusion: The present study demonstrated that HPV infection may implicate in the development of some types of breast cance

    Human papilloma virus and breast cancer: The role of inflammation and viral expressed proteins

    Get PDF
    Background: Breast cancer is currently the most common neoplasm diagnosed in women globally. There is a growing body of evidence to suggest that human papillomavirus (HPV) infection may play a key role in invasiveness of breast cancer. The aim of this study was to determine the presence of HPV in patients with breast cancer and its possible association with cancer progression. Methods: Breast specimens were collected from 72 patients with breast cancer and 31 healthy controls. The presence of HPV was investigated by polymerase chain reaction (PCR) and genotyping was performed for positive cases. We also evaluated the viral factors such as E6, E2, and E7 in HPV positive cases. Enzyme-linked immunosorbent assay (ELISA (and Real-time PCR techniques were used to measure the expression level of anti-carcinogenic genes, such as p53, retinoblastoma (RB), breast and ovarian cancer susceptibility gene (BRCA1, BRCA2) and inflammatory cytokines, including tumor necrosis factor α (TNF-α), transforming growth factor β (TGF-β), nuclear factor-kB (NF-kB), and different interleukins ILs (IL-1,IL6, and IL-17). Results: The HPV DNA was detected in 48.6% of breast cancer samples, whereas only 16.1% of controls were positive for HPV. We observed statistically significant differences between breast cancer patients and HPV presence (P = 0.003). HPV type 18 was the most prevalent virus genotype in patients. The expression of P53, RB, BRCA1, and BRCA2 were decreased in patients with HPV-positive breast cancer as compared to HPV-negative breast cancer and healthy controls. (All P-values were less than 0.05). The presence of the HPV was associated with increased inflammatory cytokines (IL-1, IL-6, IL-17, TGF-β, TNF-α, and NF-kB) and tumor progression. Conclusion: The present study demonstrated that HPV infection may implicate in the development of some types of breast cancer. © 2019 The Author(s)
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