217 research outputs found

    Retrofitting Practice of a 100kWth Coal/Biomass Air-firing Combustor to the Oxy-firing Mode: Experiences and the Experimental Results

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    Air-firing of the fossil fuels results to relatively low concentration of CO2 in flue gases which make the capture of CO2 difficult and expensive. Oxy-firing combustion is a novel method of using enriched oxygen for coal/biomass combustion with Recycled Flue Gases (RFG) to control the adiabatic flame temperature and to increase the CO2 concentration of the off-gases up to a 60-70% oxy-firing mode (compared to air-fired mode, around 12-14%). This new technology is being applied at Cranfield University to retrofit an existing 100kWth air-firing combustor to the oxy-firing mode. This paper presents the procedure of the modifications applied on the combustor and the excellent results obtained for co-firing of pulverised coal and biomass in this rig

    Anatomical Modifications in two Juncus Species under Salt Stress Conditions

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    [EN] The anatomic structure of roots and culms of two Juncus species with different degrees of salt tolerance was analysed in plants grown for two months under salt stress (NaCl treatments) and in control, non-treated plants. The aim of the study was not only to compare the anatomical structures of a halophyte (J. acutus) and a related glycophyte (J. articulatus), but mostly to assess whether salt stress induced anatomical modifications, by identifying differences between control and treated plants. Several slight differences have been indeed detected, in terms of endodermis type, development of aerenchyma and extent of sclerenchyma in perivascular sheaths. The role of Casparian endodermis was here discussed in relation to its complex implications in controlling salt influx at the root level that is an efficient mechanism involved in halophytes. Aerenchyma is a common feature found in marshy halophytes, allowing them to survive naturally under flooding conditions; however, when occurring in non-waterlogged plants, as is the case of this study, it should be regarded as a genetically, constitutive adaptation rather than an inducible one. Nevertheless, such anatomic modifications should be regarded as mere alterations due to stress that is, as stress responses and not as truly adaptations to salinity. In this context, the nature of these modifications either considered as adaptations or damage indicators of salt stress should be further reconsidered.Work in the UPV laboratories was funded by a grant to O.V. from the Spanish Ministry of Science and Innovation (Project CGL2008-00438/BOS), with contribution from the European Regional Development Fund. M.A.H. is a recipient of an Erasmus Mundus pre-doctoral scholarship financed by the European Commission (Welcome Consortium).Al Hassan, M.; Gohari, G.; Boscaiu Neagu, MT.; Vicente Meana, Ó.; Grigore, MN. (2015). Anatomical Modifications in two Juncus Species under Salt Stress Conditions. NOTULAE BOTANICAE HORTI AGROBOTANICI. 43(2):501-506. https://doi.org/10.15835/nbha43210108S50150643

    Water quality zoning in babolrood river using national sanitation foundation water quality index and geographic information system

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    Background and purpose: Quality of surface waters is important for different uses and identification of contaminated sites and pollutants leads to appropriate use of water. So, the aim of this study was to evaluate the quality of water Babolrood. Materials and methods: In this cross-sectional study, sampling was conducted in ten stations during summer 2013. Data was analyzed using National Sanitation Foundation Water Quality Index (NSFWQI) and SPSS, and then the river�s path was zoned by Geographic Information System (GIS). Results: Based on NSFWQI, the best status was found in second station (79, good) and the worst was observed in station 10 (52, moderate). Conclusion: Based on NSFWQI, the quality of river was good in upstream and moderate in downstream, indicating human as the main responsible for low quality of water. © 2016, Mazandaran University of Medical Sciences. All right reserved

    Repair of gaps opposite lesions by homologous recombination in mammalian cells

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    Damages in the DNA template inhibit the progression of replication, which may cause single-stranded gaps. Such situations can be tolerated by translesion DNA synthesis (TLS), or by homology-dependent repair (HDR), which is based on transfer or copying of the missing information from the replicated sister chromatid. Whereas it is well established that TLS plays an important role in DNA damage tolerance in mammalian cells, it is unknown whether HDR operates in this process. Using a newly developed plasmid-based assay that distinguishes between the three mechanisms of DNA damage tolerance, we found that mammalian cells can efficiently utilize HDR to repair DNA gaps opposite an abasic site or benzo[a]pyrene adduct. The majority of these events occurred by a physical strand transfer (homologous recombination repair; HRR), rather than a template switch mechanism. Furthermore, cells deficient in either the human RAD51 recombination protein or NBS1, but not Rad18, exhibited decreased gap repair through HDR, indicating a role for these proteins in DNA damage tolerance. To our knowledge, this is the first direct evidence of gap-lesion repair via HDR in mammalian cells, providing further molecular insight into the potential activity of HDR in overcoming replication obstacles and maintaining genome stability

    Liver cirrhosis mortality at national and provincial levels in Iran between 1990 and 2015: A meta regression analysis

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    Background Liver cirrhosis mortality number has increased over the last decades. We aimed to estimate the liver cirrhosis mortality rate and its trends for the first time by sex, age, geographical distribution, and cause in Iran. Method Iranian Death Registration System, along with demographic (Complete and Summary Birth History, Maternal Age Cohort and Period methods) and statistical methods (Spatio-temporal and Gaussian process regression models) were used to address the incompleteness and misclassification and uncertainty of death registration system to estimate annual cirrhosis mortality rate. Percentages of deaths were proportionally redistributed into cirrhosis due to hepatitis B, C and alcohol use based on the data from the Global Burden of Disease (GBD) 2010 study. Results Liver cirrhosis mortality in elder patients was 12 times higher than that in younger patients at national level in 2015. Over the 26 years, liver cirrhosis mortality in males has increased more than that in females. Plus, the percentage of change in age adjusted mortality rate at provincial levels varied between decreases of 64.53 to nearly 17 increase. Mortality rate has increased until 2002 and then decreased until 2015.The province with highest mortality rate in 2015 has nearly two times greater rate compare to the lowest. More than 60 of liver cirrhosis mortality cases at national level are caused by hepatitis B and C infection. The rate of hepatitis B mortality is four times more than that from hepatitis C. Conclusion This study demonstrated an increasing and then decreasing pattern in cirrhosis mortality that could be due to national vaccination of hepatitis B program. However monitoring, early detection and treatment of risk factors of cirrhosis, mainly in high risk age groups and regions are essential. Cirrhosis mortality could be diminished by using new non-invasive methods of cirrhosis screening, hepatitis B vaccination, definite treatment of hepatitis C. © 2019 Rezaei et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Liver cancer mortality at national and provincial levels in Iran between 1990 and 2015: A meta regression analysis

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    Background: Liver cancer is a highly lethal cancer with 5 year survival rate of about 18. This cancer is a leading cause of death in many countries. As there is not a comprehensive population base study on liver cancer mortality rates by cause in national and provincial level in Iran. We aimed to estimate the liver cancer mortality rate, its patterns, and temporal trends during 26 years by sex, age, geographical distribution, and cause. Methods: We used the Iranian death registration system (DRS), in addition to demographic and statistical methods, to address the incompleteness and misclassification and uncertainty of death registration system to estimate annual liver cancer mortality rate. Direct age standardized approach was applied using Iran national population 2015 as a standard population to facilitate the comparison between the provinces. Results: Liver cancer age standardized mortality rate in Iran increased by more than four times from 1.18 (95 uncertainty interval; 0.86 to 1.61) deaths per 100,000 person in 1990 to 5.66 (95 uncertainty interval; 4.20 to 7.63) deaths per 100,000 person in 2015. Male to female age adjusted mortality ratio changed from 0.87 to 1.82 during the 26 years of the study. With increasing age, liver cancer mortality rate increased in both sex and all provinces. At provincial level, the province with highest mortality rate have 2.96 times greater rate compare to the lowest. Generally, about 71 of mortality at national level is due to hepatitis B and C infection. Conclusions: In order to reduce liver cancer mortality rate, it is recommended to control main risk factors including chronic hepatitis infections. Because of the growing rate of mortality from liver cancer, augmenting life expectancy, and increasing number of the elderly in Iran, policy makers are more expected to adopt measures including hepatitis B vaccination or hepatitis C treatment. © 2018, Hepatitis Monthly

    Liver cancer mortality at national and provincial levels in Iran between 1990 and 2015: A meta regression analysis

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    Background: Liver cancer is a highly lethal cancer with 5 year survival rate of about 18. This cancer is a leading cause of death in many countries. As there is not a comprehensive population base study on liver cancer mortality rates by cause in national and provincial level in Iran. We aimed to estimate the liver cancer mortality rate, its patterns, and temporal trends during 26 years by sex, age, geographical distribution, and cause. Methods: We used the Iranian death registration system (DRS), in addition to demographic and statistical methods, to address the incompleteness and misclassification and uncertainty of death registration system to estimate annual liver cancer mortality rate. Direct age standardized approach was applied using Iran national population 2015 as a standard population to facilitate the comparison between the provinces. Results: Liver cancer age standardized mortality rate in Iran increased by more than four times from 1.18 (95 uncertainty interval; 0.86 to 1.61) deaths per 100,000 person in 1990 to 5.66 (95 uncertainty interval; 4.20 to 7.63) deaths per 100,000 person in 2015. Male to female age adjusted mortality ratio changed from 0.87 to 1.82 during the 26 years of the study. With increasing age, liver cancer mortality rate increased in both sex and all provinces. At provincial level, the province with highest mortality rate have 2.96 times greater rate compare to the lowest. Generally, about 71 of mortality at national level is due to hepatitis B and C infection. Conclusions: In order to reduce liver cancer mortality rate, it is recommended to control main risk factors including chronic hepatitis infections. Because of the growing rate of mortality from liver cancer, augmenting life expectancy, and increasing number of the elderly in Iran, policy makers are more expected to adopt measures including hepatitis B vaccination or hepatitis C treatment. © 2018, Hepatitis Monthly

    Role for the Mammalian Swi5-Sfr1 Complex in DNA Strand Break Repair through Homologous Recombination

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    In fission yeast, the Swi5-Sfr1 complex plays an important role in homologous recombination (HR), a pathway crucial for the maintenance of genomic integrity. Here we identify and characterize mammalian Swi5 and Sfr1 homologues. Mouse Swi5 and Sfr1 are nuclear proteins that form a complex in vivo and in vitro. Swi5 interacts in vitro with Rad51, the DNA strand-exchange protein which functions during HR. By generating Swi5−/− and Sfr1−/− embryonic stem cell lines, we found that both proteins are mutually interdependent for their stability. Importantly, the Swi5-Sfr1 complex plays a role in HR when Rad51 function is perturbed in vivo by expression of a BRC peptide from BRCA2. Swi5−/− and Sfr1−/− cells are selectively sensitive to agents that cause DNA strand breaks, in particular ionizing radiation, camptothecin, and the Parp inhibitor olaparib. Consistent with a role in HR, sister chromatid exchange induced by Parp inhibition is attenuated in Swi5−/− and Sfr1−/− cells, and chromosome aberrations are increased. Thus, Swi5-Sfr1 is a newly identified complex required for genomic integrity in mammalian cells with a specific role in the repair of DNA strand breaks
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