Computer Simulation of Catalytic Oxidation of Gaseous Ammonia in Bubbling Fluidized Bed

Catalytic conversion of ammonia in bubbling fluidized bed has been simulated using three different hydrodynamic models: (a) Kunii and Levenspiel model, (b) Simple two-phase model, and (c) Dynamic two-phase model. The basic differences between the models lie in the assumptions and mass transfer correlations used to describe the hydrodynamics of the fluidized bed. This study compares the predictions of the performance of a fluidized bed reactor by different models, comparing with experimental data of ammonia oxidation using metal oxide catalysts. The predictions from all the models compared well with the experimental data within acceptable levels of error. The variations among the models were found to be insignificant. However, simulation of the model to assess the effect of different hydrodynamic parameters, including gas velocity, bed diameter and particle size, and bed density on conversion showed significant variation among the models

Infection of skipjack tuna Katsuwonus pelamis (Linnaeus 1758) of Oman Sea with cestode Trypanorhyncha (Diesing 1863)

Numerous reports on existence of white cysts in musculature of skipjack tuna Katsuwonus pelamis and lack of information about the quality of cysts and individual responses of fish to them led the authors to focus on this fish as a commercially valuable species. This study investigated the histopathologic responses of skipjack tuna to highly prevalent cystic larval stages of Trypanorhyncha. Some 92.25% of 400 examined skipjack tuna of Oman Sea (Iran) captured from processing center in Chabahar have been diagnosed infected by Trypanorhyncha Larvae through gross muscle examination. Minimum of 5 to maximum of 19 cysts were observed per each flank flesh with no significant difference between number of cysts from right (9 ± 4) and left flanks (10 ± 4) and also males and females (p>.05, t- student test (spss version 16)). Using hematoxylin and eosin (H&E) staining of 4µm sections of surrounded cysts with muscle and light microscopy observations each metacestode was distinguished encapsulated by surrounding fibrous cyst wall consists of thin inner layer and a thick outer layer with the minimal histopathologic changes around it. The highly prevalent Trypanorhyncha infection in Oman Sea represents the high rate of infection among elasmobranches. The ability of encapsulated parasite to escape from the immune system of the host is assumed as one reason for the observed minimal tissue response in infected fish and the continuation of infection among elasmobranches and teleosts of Omen Sea

Gasification conversion and char reactivity of rubber seed shell and high density polyethylene mixtures using steam Co-Gasification process

Due to the recent surge of global energy demand and the fear of climate change, an extensive attention from worldwide in seeking for cleaner alternative means of renewable energy and this has been a topic of interest widely. With the abundance supply of biomass and plastic waste generated annually and finding an effective method in utilizing these wastes, leads to a notion of using these wastes in the co-gasification process. Although there are studies on co-gasification of biomass and waste mixtures, limited studies focused on the understanding of the char reactivity and gasification conversion of this mixture. Hence, an experimental study on steam co-gasification of rubber seed shell and high density polyethylene mixtures in argon atmosphere is carried out using thermogravimetric (TGA) approach under non-isothermal condition. This work presents the surface physical morphology of rubber seed shell (RSS), high density polyethylene (HDPE), and its mixtures. Furthermore, the char conversion and char reactivity of RSS, HDPE, and their mixtures at different proportions are investigated in both pyrolysis and gasification process. The argon gas is supplied at a flowrate of 100 mL min-1and the steam is generated from superheater at 383 K whilst injected at flowrate of 3000 µL h-1into the TGA system

Use of evidence to support healthy public policy: a policy effectiveness-feasibility loop

Public policy plays a key role in improving population health and in the control of diseases, including non-communicable diseases. However, an evidence-based approach to formulating healthy public policy has been difficult to implement, partly on account of barriers that hinder integrated work between researchers and policy-makers. This paper describes a “policy effectiveness–feasibility loop” (PEFL) that brings together epidemiological modelling, local situation analysis and option appraisal to foster collaboration between researchers and policy-makers. Epidemiological modelling explores the determinants of trends in disease and the potential health benefits of modifying them. Situation analysis investigates the current conceptualization of policy, the level of policy awareness and commitment among key stakeholders, and what actually happens in practice, thereby helping to identify policy gaps. Option appraisal integrates epidemiological modelling and situation analysis to investigate the feasibility, costs and likely health benefits of various policy options. The authors illustrate how PEFL was used in a project to inform public policy for the prevention of cardiovascular diseases and diabetes in four parts of the eastern Mediterranean. They conclude that PEFL may offer a useful framework for researchers and policy-makers to successfully work together to generate evidence-based policy, and they encourage further evaluation of this approach

Performance Prediction of Waste Polyethylene Gasification Using CO2 in a Bubbling Fluidized Bed: A Modelling Study

Gasification of carbonaceous materials using CO2 from flue gases is an effective and economic means of waste recycling and environmental CO2 mitigation system. The paper presents investigation on conversion of plastics, such as (poly) ethylene, into valuable gaseous products, primarily Syngas or synthesis gas using CO2 as a gasifying agent instead of conventional steam. Typically, gasification is carried out in a fluidized bed reactor followed by sequential separation of syngas from tar and other undesired gaseous products. In this research work, the effect of operating conditions of the fluidized bed reactor on carbon conversion and H 2/CO mole ratio was examined. For this purpose, a process model of CO2 gasification of waste plastics using fluidized bed reactor was developed in ASPEN PLUS®. Sensitivity analysis concluded that parameters like CO2 – feed ratio, residence time, and gasification temperature serve to control the yield and quality of syngas. This work is licensed under a Creative Commons Attribution 4.0 International License

Follow-up of CRT-D patients downgraded to CRT-P at the time of generator exchange

Background: Some patients with cardiac resynchronisation therapy (CRT) experience super-response (LVEF improvements to ≥50%). At generator exchange (GE), downgrading (DG) from CRT-defibrillator (CRT-D) to CRT-pacemaker (CRT-P) could be an option for these patients on primary prevention ICD indication and no required ICD therapies. Long-term data on arrhythmic events in super-responders is scarce. Methods: CRT-D patients with LVEF improvement to ≥50% at GE were identified in four large centres for retrospective analysis. Mortality, significant ventricular tachyarrhythmia and appropriate ICD-therapy were determined, and patient analysis was split into two groups (downgraded to CRT-P or not). Results: Sixty-six patients (53% male, 26% coronary artery disease) on primary prevention were followed for a median of 129 months [IQR: 101–155] after implantation. 27 (41%) patients were downgraded to CRT-P at GE after a median of 68 [IQR: 58–98] months (LVEF 54% ± 4%). The other 39 (59%) continued with CRT-D therapy (LVEF 52% ± 6%). No cardiac death or significant arrhythmia occurred in the CRT-P group (median follow-up (FU) 38 months [IQR: 29–53]). Three appropriate ICD-therapies occurred in the CRT-D group [median FU 70 months (IQR: 39–97)]. Annualized event-rates after DG/GE were 1.5%/year and 1.0%/year in the CRT-D group and the whole cohort, respectively. Conclusions: No significant tachyarrhythmia were detected in the patients downgraded to CRT-P during follow-up. However, three events were observed in the CRT-D group. Whilst downgrading CRT-D patients is an option, a small residual risk for arrhythmic events remains and decisions regarding downgrade should be made on a case-by-case basis.</p

Phenotype Algorithms for the Identification and Characterization of Vaccine-Induced Thrombotic Thrombocytopenia in Real World Data: A Multinational Network Cohort Study

INTRODUCTION: Vaccine-induced thrombotic thrombocytopenia (VITT) has been identified as a rare but serious adverse event associated with coronavirus disease 2019 (COVID-19) vaccines. OBJECTIVES: In this study, we explored the pre-pandemic co-occurrence of thrombosis with thrombocytopenia (TWT) using 17 observational health data sources across the world. We applied multiple TWT definitions, estimated the background rate of TWT, characterized TWT patients, and explored the makeup of thrombosis types among TWT patients. METHODS: We conducted an international network retrospective cohort study using electronic health records and insurance claims data, estimating background rates of TWT amongst persons observed from 2017 to 2019. Following the principles of existing VITT clinical definitions, TWT was defined as patients with a diagnosis of embolic or thrombotic arterial or venous events and a diagnosis or measurement of thrombocytopenia within 7 days. Six TWT phenotypes were considered, which varied in the approach taken in defining thrombosis and thrombocytopenia in real world data. RESULTS: Overall TWT incidence rates ranged from 1.62 to 150.65 per 100,000 person-years. Substantial heterogeneity exists across data sources and by age, sex, and alternative TWT phenotypes. TWT patients were likely to be men of older age with various comorbidities. Among the thrombosis types, arterial thrombotic events were the most common. CONCLUSION: Our findings suggest that identifying VITT in observational data presents a substantial challenge, as implementing VITT case definitions based on the co-occurrence of TWT results in large and heterogeneous incidence rate and in a cohort of patints with baseline characteristics that are inconsistent with the VITT cases reported to date

Phenotype Algorithms for the Identification and Characterization of Vaccine-Induced Thrombotic Thrombocytopenia in Real World Data:A Multinational Network Cohort Study

INTRODUCTION: Vaccine-induced thrombotic thrombocytopenia (VITT) has been identified as a rare but serious adverse event associated with coronavirus disease 2019 (COVID-19) vaccines. OBJECTIVES: In this study, we explored the pre-pandemic co-occurrence of thrombosis with thrombocytopenia (TWT) using 17 observational health data sources across the world. We applied multiple TWT definitions, estimated the background rate of TWT, characterized TWT patients, and explored the makeup of thrombosis types among TWT patients. METHODS: We conducted an international network retrospective cohort study using electronic health records and insurance claims data, estimating background rates of TWT amongst persons observed from 2017 to 2019. Following the principles of existing VITT clinical definitions, TWT was defined as patients with a diagnosis of embolic or thrombotic arterial or venous events and a diagnosis or measurement of thrombocytopenia within 7 days. Six TWT phenotypes were considered, which varied in the approach taken in defining thrombosis and thrombocytopenia in real world data. RESULTS: Overall TWT incidence rates ranged from 1.62 to 150.65 per 100,000 person-years. Substantial heterogeneity exists across data sources and by age, sex, and alternative TWT phenotypes. TWT patients were likely to be men of older age with various comorbidities. Among the thrombosis types, arterial thrombotic events were the most common. CONCLUSION: Our findings suggest that identifying VITT in observational data presents a substantial challenge, as implementing VITT case definitions based on the co-occurrence of TWT results in large and heterogeneous incidence rate and in a cohort of patints with baseline characteristics that are inconsistent with the VITT cases reported to date. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40264-022-01187-y

International cohort study indicates no association between alpha-1 blockers and susceptibility to COVID-19 in benign prostatic hyperplasia patients

Purpose: Alpha-1 blockers, often used to treat benign prostatic hyperplasia (BPH), have been hypothesized to prevent COVID-19 complications by minimising cytokine storm release. The proposed treatment based on this hypothesis currently lacks support from reliable real-world evidence, however. We leverage an international network of large-scale healthcare databases to generate comprehensive evidence in a transparent and reproducible manner.Methods: In this international cohort study, we deployed electronic health records from Spain (SIDIAP) and the United States (Department of Veterans Affairs, Columbia University Irving Medical Center, IQVIA OpenClaims, Optum DOD, Optum EHR). We assessed association between alpha-1 blocker use and risks of three COVID-19 outcomes-diagnosis, hospitalization, and hospitalization requiring intensive services-using a prevalent-user active-comparator design. We estimated hazard ratios using state-of-the-art techniques to minimize potential confounding, including large-scale propensity score matching/stratification and negative control calibration. We pooled database-specific estimates through random effects meta-analysis.Results: Our study overall included 2.6 and 0.46 million users of alpha-1 blockers and of alternative BPH medications. We observed no significant difference in their risks for any of the COVID-19 outcomes, with our meta-analytic HR estimates being 1.02 (95% CI: 0.92-1.13) for diagnosis, 1.00 (95% CI: 0.89-1.13) for hospitalization, and 1.15 (95% CI: 0.71-1.88) for hospitalization requiring intensive services.Conclusion: We found no evidence of the hypothesized reduction in risks of the COVID-19 outcomes from the prevalent-use of alpha-1 blockers-further research is needed to identify effective therapies for this novel disease.</p

A Proinflammatory Cytokine Inhibits P53 Tumor Suppressor Activity

p53 has a key role in the negative regulation of cell proliferation, in the maintenance of genomic stability, and in the suppression of transformation and tumorigenesis. To identify novel regulators of p53, we undertook two functional screens to isolate genes which bypassed either p53-mediated growth arrest or apoptosis. In both screens, we isolated cDNAs encoding macrophage migration inhibitory factor (MIF), a cytokine that was shown previously to exert both local and systemic proinflammatory activities. Treatment with MIF overcame p53 activity in three different biological assays, and suppressed its activity as a transcriptional activator. The observation that a proinflammatory cytokine, MIF, is capable of functionally inactivating a tumor suppressor, p53, may provide a link between inflammation and tumorigenesis