Thermal decomposition and gasification of biomass pyrolysis gases using a hot bed of waste derived pyrolysis char

Chars produced from the pyrolysis of different waste materials have been investigated in terms of their use as a catalyst for the catalytic cracking of biomass pyrolysis gases during the two-stage pyrolysis-gasification of biomass. The chars were produced from the pyrolysis of waste tyres, refused derived fuel and biomass in the form of date stones. The results showed that the hydrocarbon tar yields decreased significantly with all the char materials used in comparison to the non-char catalytic experiments. For example, at a cracking temperature of 800 °C, the total product hydrocarbon tar yield decreased by 70% with tyre char, 50% with RDF char and 9% with biomass date stones char compared to that without char. There was a consequent increase in total gas yield. Analysis of the tar composition showed that the content of phenolic compounds decreased and polycyclic aromatic hydrocarbons increased in the product tar at higher char temperatures

Experimental investigation of tar arresting techniques and their evaluation for product syngas cleaning from bubbling fluidized bed gasifier

© 2019 Elsevier Ltd Hazardous waste products along with the syngas produced from biomass gasification are one of the major problems of today world. Tar and other solid contaminants removal from syngas are necessary as it is widely used for the production of energy in thermal and power sectors. The raw syngas can be clean up by directly controlling the operating parameters and applying cleaning units. This study aimed to analyze bubbling fluidized bed gasifier and focuses on investigating the novel tar reducing techniques. Different cleaning units; char bed, woodchip bed and mop fan were used to arrest tar directly from producer gas. For the first time, a novel strategical technique of mop fan based on water spray was evaluated. Results showed that tar arrest with bio-char is unsuccessful due to the burning of bed while the average concentration of tar captured by woodchips and mop fan with or without water spray was 0.459 mg/L, 0.987 mg/L and 0.617 mg/L respectively. Furthermore, the concentration of naphthalene and phenanthrene reduced significantly by 96.46% and 99.27% with water spray based mop fan. Overall tar arresting percentage efficiency with small woodchip, large woodchip, mop fan without water and mop fan with water spray was 22.5% < 29.4% < 60.54% < 89.61% respectively. Hence, these investigations lead to the important findings that mop fan with water spray can be deployed directly to capture contaminants, to prevent the production of waste and to increase the efficiencies of clean syngas for the safer use in the power sector

Editing of HIV-1 RNA by the double-stranded RNA deaminase ADAR1 stimulates viral infection

Adenosine deaminases that act on dsRNA (ADARs) are enzymes that target double-stranded regions of RNA converting adenosines into inosines (A-to-I editing) thus contributing to genome complexity and fine regulation of gene expression. It has been described that a member of the ADAR family, ADAR1, can target viruses and affect their replication process. Here we report evidence showing that ADAR1 stimulates human immuno deficiency virus type 1 (HIV-1) replication by using both editing-dependent and editing-independent mechanisms. We show that over-expression of ADAR1 in HIV-1 producer cells increases viral protein accumulation in an editing-independent manner. Moreover, HIV-1 virions generated in the presence of over-expressed ADAR1 but not an editing-inactive ADAR1 mutant are released more efficiently and display enhanced infectivity, as demonstrated by challenge assays performed with T cell lines and primary CD4+ T lymphocytes. Finally, we report that ADAR1 associates with HIV-1 RNAs and edits adenosines in the 5′ untranslated region (UTR) and the Rev and Tat coding sequence. Overall these results suggest that HIV-1 has evolved mechanisms to take advantage of specific RNA editing activity of the host cell and disclose a stimulatory function of ADAR1 in the spread of HIV-1

Management of multidrug resistant Gram-negative bacilli infections in solid organ transplant recipients: SET/GESITRA-SEIMC/REIPI recommendations

Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant (MDR) Gram-negative bacilli (GNB), as they are frequently exposed to antibiotics and the healthcare setting, and are regulary subject to invasive procedures. Nevertheless, no recommendations concerning prevention and treatment are available. A panel of experts revised the available evidence; this document summarizes their recommendations: (1) it is important to characterize the isolate´s phenotypic and genotypic resistance profile; (2) overall, donor colonization should not constitute a contraindication to transplantation, although active infected kidney and lung grafts should be avoided; (3) recipient colonization is associated with an increased risk of infection, but is not a contraindication to transplantation; (4) different surgical prophylaxis regimens are not recommended for patients colonized with carbapenem-resistant GNB; (5) timely detection of carriers, contact isolation precautions, hand hygiene compliance and antibiotic control policies are important preventive measures; (6) there is not sufficient data to recommend intestinal decolonization; (7) colonized lung transplant recipients could benefit from prophylactic inhaled antibiotics, specially for Pseudomonas aeruginosa; (8) colonized SOT recipients should receive an empirical treatment which includes active antibiotics, and directed therapy should be adjusted according to susceptibility study results and the severity of the infection.J.T.S. holds a research contract from the Fundación para la Formación e Investigación de los Profesionales de la Salud de Extremadura (FundeSalud), Instituto de Salud Carlos III. M.F.R. holds a clinical research contract “Juan Rodés” (JR14/00036) from the Spanish Ministry of Economy and Competitiveness, Instituto de Salud Carlos III

Correlation between plasma glucose and hemoglobin A1c in HIV-infected individuals receiving zidovudine and non-zidovudine containing antiretroviral therapy regimens

Background Hemoglobin A1c (HbA1c) has been used for the diagnosis of diabetes and glycemic monitoring. However, using HbA1c for glycemia estimation has some fallacies in anemic persons. Zidovudine (AZT) treatment is associated with anemia and/or increased mean corpuscular volume (MCV). Objective This study aimed to compare the correlation between HbA1c and plasma glucose in HIV-infected individuals who were receiving AZT and non-AZT containing regimens. Methods A cross-sectional study was conducted in 150 HIV-infected individuals. We evaluated the correlation of paired fasting plasma glucose (FPG), random plasma glucose (RPG), mean plasma glucose (MPG) and HbA1c values by using Pearson correlation. Multivariate linear regression was used to determine the associated factors of HbA1c. Results The mean age was 49.0 ± 10.5 years, and 60.0% were male. Thirteen patients (8.7%) had diabetes and 14 patients (9.3%) had anemia. There were significant correlations between HbA1c and plasma glucose (FPG, RPG, and MPG; p < 0.05, all). The correlation between HbA1c and MPG in patients receiving AZT [HbA1c = 3.18 + 0.02MPG; R2=0.44] and not receiving AZT [HbA1c = 3.76 + 0.02MPG; R2=0.43] indicated that HbA1c in patients receiving AZT was 0.58% underestimated. Multivariate linear regression analysis showed that hematocrit [β 0.192; 95% confidence interval (CI) 0.003, 0.690; p = 0.032] and MCV [β −0.195; 95% CI -0.326, −0.002; p = 0.047] were associated with HbA1c levels. Conclusions HbA1c underestimates glycemia in HIV-infected individuals receiving AZT containing regimens. Factors associated with decreased HbA1c levels in HIV-infected individuals included decreased hematocrit and increased MCV. In HIV-infected individuals receiving AZT, using HbA1c for diabetes diagnosis or glycemia monitoring should be cautiously interpreted

Tar removal from biomass pyrolysis gas in two-step function of decomposition and adsorption

Tar content in syngas pyrolysis is a serious problem for fuel gas utilization in downstream applications. This paper investigated tar removal, by the two-step function of decomposition and adsorption, from the pyrolysis gas. The temperature of the tar decomposition process was fixed at 800 °C both with and without steam, with air as the reforming agent. Both steam and air had a strong influence on the tar decomposition reaction. The reduction of the gravimetric tar mass was 78% in the case of the thermal cracking, whereas, it was in the range of 77-92% in the case of the steam and air forming. Under conditions of tar decomposition, the gravimetric tar mass reduced, while the yield of the combustible gaseous components in the syngas increased. Synchronously, the amount of light tars increased. This should be eliminated later by fixed-bed adsorption. Three adsorbents (activated carbon, wood chip, and synthetic porous cordierite) were selected to evaluate the adsorption performance of light tars, especially of condensable tar. Activated carbon showed the best adsorption performance among all light tars, in view of the adsorption capacity and breakthrough time. On the other hand, activated carbon decreased the efficiency of the system due to its high adsorption performance with non-condensable tar, which is a combustible substance in syngas. Synthetic porous cordierite showed very low adsorption performance with almost all light tars, whereas, wood chip showed a high adsorption performance with condensable tar and low adsorption performance with non-condensable tar. When compared with other adsorbents, wood chip showed a prominent adsorption selectivity that was suitable for practical use, by minimizing the condensable tar without decreasing the efficiency of the system.Biomass pyrolysis Tar removal Tar decomposition Thermal cracking Reforming Tar adsorption