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An indirectly heated tubular reactor is fabricated and used to study methane thermal decomposition conversion and determine kinetic parameters. A combined perfectly mixed reactor with bypass (CPMR) is proposed as an alternative to the traditional perfectly mixed and plug flow reactors. The CPMR model is used in order to account for buoyancy flow in the reactor. Results comparing the numerical predictions from all three models to experimental data show that buoyancy effects are significant in the reactor under study and also in most reactors in the literature. Including this effect might significantly improve the accuracy of the model predictions. The CPMR reactor model with a reaction rate constant of 5.43 × 10 15 1/s and an activation energy of 420.7 kJ/mol is capable of reproducing the obtained experimental data in this study and in the literature. [ABSTRACT FROM AUTHOR]

Abstract: Previous work assessed the fundamental technical and market risks associated with the development and deployment of solar fuels technology in Alberta. It identified methane cracking in solar-molten media as the hydrogen production technology featuring the best combination of technical risk, market acceptance, and breakthrough potential of all the techniques covered in the study. Alberta Innovates – Technology Futures (AITF) plans to advance the technology from a conceptual stage to a proof-of concept over a span of 4 years. The ultimate goal is to design, build and test a prototype solar receiver/reactor in a suitable solar simulator. The paper outlines the activities to date concerning the initial bench-scale testing of methane cracking in molten media at temperatures ranging from 1023 to 1373K. The design and construction of an experimental apparatus used to establish the fundamental thermo-chemical performance of the process is presented, along with preliminary results and lessons from the first testing campaign. A transient, non-isothermal, preliminary mathematical model of a reacting bubble within the molten metal has been developed using MATLAB. The model accounts for the chemical reactions, diffusion of the gases in the bubble and heat transfer from the molten metal to the reacting gases. The model can be used to predict the minimum bubble residence time needed to achieve a given hydrogen yield. The simulation tool will be used to numerically estimate methane conversions in the reactor at various conditions. [Copyright &y& Elsevier]

Abstract: The Heartland Area Redwater Project (HARP) aims to inject and geologically store up to a gigatonne of captured CO2 derived from Alberta’s Industrial Heartland. The storage formation will be the vast water leg of the Devonian Redwater-Leduc carbonate reef structure, also host to Canada’s third largest conventional oil pool. Extensive characterization activities, including geological, geophysical, hydrogeological, geochemical, soil, atmospheric studies and land management practices are currently nearing completion. Combined information from these studies is allowing for the integration and development of conceptual and numerical models. Intensive activity is currently focused upon a small pilot site within the water leg of the reef. Should this pilot program prove to be successful, CO2 injection, and the associated monitoring program, may be scaled up to allow an annual injection of up to 1 million tonnes of CO2. The integration of near surface characterization and monitoring along with injection formation characterization (e.g. fluid sampling and time-series geophysics) and well integrity studies have guided the design and implementation of the HARP assurance monitoring program. Field data acquisition and interpretation are currently ongoing to allow a preoperational phase, pilot-scale, assurance monitoring baseline to be established. Public consultation and stakeholder involvement with the project forms a key component in both implementing the program, and allowing for sustainable agricultural and industrial development within the Alberta Industrial Heartland area. [Copyright &y& Elsevier]

Background: Invisible Condom gel formulations being developed as microbicides to prevent the sexual transmission of HIV are advancing through the phases of clinical trials. The objectives of this study were to evaluate, after 8 weeks of vaginal application, the extended safety and acceptability of two Invisible Condom vaginal gel formulations: (i) the polymer alone and (ii) the polymer containing sodium lauryl sulfate (SLS) compared to placebo.Study Design: This study is a randomized, doubled-blind, placebo-controlled Phase II extended safety study in healthy sexually active women from Yaoundé, Cameroon. Women were randomized into three gel arms: (i) placebo, (ii) polymer alone and (iii) polymer/SLS. Women applied gel intravaginally twice daily for 8 weeks.Results: A total of 194 sexually active women applied placebo (n=41), polymer alone (n=76) and polymer/SLS (n=77). Invisible Condom gel formulations were well tolerated with no reported serious adverse events. The majority of reported adverse events were mild or moderate and mostly similar in all three arms, except for pelvic pain that was 10% higher in the polymer and polymer/SLS arms compared to placebo. Colposcopy showed neither genital ulceration nor mucosal lesions. Nugent score, H(2)O(2)-producing lactobacilli and vaginal pH were not affected by the study products. The gel formulations and applicator were generally acceptable and comfortable.Conclusion: This extended safety study showed that the Invisible Condom gel formulations and applicator were well tolerated and acceptable when applied intravaginally twice daily for 8 weeks. Thus, further phases of clinical development of Invisible Condom as a potential microbicide to prevent sexual transmission of HIV are warranted. [ABSTRACT FROM AUTHOR]

Abstract: The sooting behaviour of binary fuel mixtures was evaluated both experimentally and through computer simulations. The soot volume fraction in laminar diffusion flames of mixtures of ethylene/propane, methane/ethylene, methane/propane, methane/ethane, methane/butane, ethane/propane and ethane/ethylene fuels was measured using 2-dimensional line of sight attenuation. A synergistic effect was observed for the ethylene/propane, methane/ethylene, methane/ethane and ethane/ethylene mixtures. The synergistic effect translated into a higher soot concentration for a mixture fraction than could be yielded by the added contribution of both pure fuels. Such an effect was not observed for the methane/propane, methane/butane and ethane/propane mixtures. Through experiments in which the flame temperature was kept constant, it was determined that the synergistic effect in the methane/ethylene mixture is very temperature dependent whereas, that in the ethylene/propane mixture is not. This phenomenon was further studied through the modeling of the ethylene/propane mixture. Numerical simulations were carried out using two different soot models. The simulations confirmed the presence of a synergistic effect. It was found that the effect could be directly correlated to a synergistic effect in the concentration of n-C4H5 and n-C4H3, which could be traced back to an interaction between ethylene and methyl radical species. These results yield further insight into the pathways to soot formation and highlight the importance of further analyzing binary fuel mixtures as a means of understanding soot formation in practical devices using industrial fuels. [Copyright &y& Elsevier]

The presence of GABA and galanin in histaminergic neurons was previously reported in the rodent brain but whether such co-localizations also occur in the human brain was not known. We used in situ hybridization histochemistry and immunohistochemistry to study the co-localization of histamine with GABA and galanin in neurons of the tuberomamillary nucleus of adult human posterior hypothalamus. On consecutive formalin-fixed paraffin-embedded sections, co-localization was assessed using the in situ hybridization for l-histidine decarboxylase mRNA and immunocytochemistry for glutamate decarboxylase-67 kDa or galanin in the two profiles of same cell. The pattern of distribution and number of histaminergic neurons identified by in situ hybridization of the synthesizing enzyme gene transcripts were in accordance with data reported for histamine immunoreactivity. The great majority of neurons within the main divisions of the tuberomamillary nucleus containing l-histidine decarboxylase mRNA was also immunoreactive for glutamate decarboxylase-67 kDa. The range of co-localization of the two markers varied from 72% in the lateral part, to 75–87% in the medial part and 83–88% in the ventral part. In contrast, no cell containing l-histidine decarboxylase mRNA was immunoreactive for galanin. We conclude that tuberomamillary neurons in human co-express histamine with GABA but, unlike the neurons in rodents, do not express galanin, indicating that neurotransmitter co-localization patterns differ in the two species. [Copyright &y& Elsevier]

A somatostatin deficit occurs in the cerebral cortex of Alzheimer''s disease patients without a major loss in somatostatin-containing neurons. This deficit could be related to a reduction in the rate of proteolytic processing of peptide precursors. Since the two proprotein convertases (PC)1 and PC2 are responsible for the processing of neuropeptide precursors directed to the regulated secretory pathway, we examined whether they are involved first in the proteolytic processing of prosomatostatin in mouse and human brain and secondly in somatostatin defect associated with Alzheimer''s disease. By size exclusion chromatography, the cleavage of prosomatostatin to somatostatin-14 is almost totally abolished in the cortex of PC2 null mice, while the proportions of prosomatostatin and somatostatin-28 are increased. By immunohistochemistry, PC1 and PC2 were localized in many neuronal elements in human frontal and temporal cortex. The convertases levels were quantified by Western blot, as well as the protein 7B2 which is required for the production of active PC2. No significant change in PC1 levels was observed in Alzheimer''s disease. In contrast, a marked decrease in the ratio of the PC2 precursor to the total enzymatic pool was observed in the frontal cortex of Alzheimer patients. This decrease coincides with an increase in the binding protein 7B2. However, the content and enzymatic activity of the PC2 mature form were similar in Alzheimer patients and controls. Therefore, the cortical somatostatin defect is not due to convertase alteration occuring during Alzheimer''s disease. Further studies will be needed to assess the mechanisms involved in somatostatin deficiency in Alzheimer''s disease. [Copyright &y& Elsevier]