Thermodynamic analysis of methanation of palm empty fruit bunch (PEFB) pyrolysis oil with and without in situ CO2 sorption

Thermodynamic equilibrium analysis for conversion of palm empty fruit bunch (PEFB) bio-oil to methane using low-temperature steam reforming (LTSR) process was conducted by assuming either isothermal or adiabatic condition, with and without sorption enhancement (SE-LTSR), with CaO(S) or Ca(OH)2(S) as CO2 sorbent. Temperatures of 300-800 K, molar steam to carbon (S/C) ratios of 0.3-7.0, pressures of 1-30 atm and molar calcium to carbon ratios (Ca:C) of 0.3-1.0 were simulated. For reasons of process simplicity, the best conditions for CH4 production were observed for the adiabatic LTSR process without sorption at S/C between 2.5 and 3 (compared to the stoichiometric S/C of 0.375), inlet temperature above 450 K, resulting in reformer temperature of 582 K, where close to the theoretical maximum CH4 yield of 38 wt % of the simulated dry PEFB oil was obtained, resulting in a reformate consisting of 44.5 vol % CH4, 42.7 vol % CO2 and 12.7 vol % H2 and requiring only moderate heating mainly to partially preheat the reactants. Temperatures and S/C below these resulted in high risk of carbon by-product

Structure and Dynamics of a Fusion Peptide Helical Hairpin on the Membrane Surface: Comparison of Molecular Simulations and NMR

The conserved N-terminal residues of the HA2 subunit of influenza hemagglutinin (fusion peptide) are essential for membrane fusion and viral entry. Recent NMR studies showed that the 23-residue fusion peptide forms a helical hairpin that undergoes rocking motion relative to the membrane surface on a nanosecond time scale. To compare with NMR and to obtain a detailed molecular picture of the peptide–membrane interaction, we performed molecular dynamics simulations of the fusion peptide in explicit dimyristoylphosphatidylcholine and with the IMM1 implicit membrane model. To account for low and neutral pH conditions, simulations were performed with acidic groups (E11 and D19) protonated and unprotonated, respectively. The hairpin structure was stable in the simulations, with the N-terminal helix buried more deeply into the hydrophobic membrane interior than the C-terminal helix. Interactions between the tryptophans in the fusion peptide and phospholipid residues contribute to peptide orientation. Higher flexibility of the hairpin was observed in the implicit membrane simulations. Internal correlation functions of backbone N–H vectors were fit to the extended Lipari–Szabo model-free approach to obtain order parameters and correlation times. Good agreement with the NMR results was obtained for orientational fluctuations around the hairpin axis (rotation), but those around the perpendicular axis (tilting) were more limited in the simulations than inferred from the NMR experiments

Using Mobile Technology to Facilitate Reactive Case Detection of Malaria

ObjectiveThis presentation will share findings from more than three years ofusing mobile technology for reactive case detection (RACD) to helpeliminate malaria in a well-defined geographic area. It will reviewthe concepts of RACD, the application of mobile technology, lessonslearned from more than three years of application, and considerationsin applying this technology in other malaria elimination contexts.IntroductionZanzibar is comprised primarily of two large islands with apopulation of 1.3 million. Indoor Residual Spraying (IRS) campaigns,distribution of long-lasting insecticide treated bed nets (LLINs),and use of Rapid Diagnostic Tests (RDTs) have reduced Malariaprevalence from 39% in 2005 to less than 1% in 2011-2012. Asmalaria burden decreases, there is an increasing need to track andfollow up individual cases to contain transmission that could lead toresurgence. One method being used to achieve these aims is reactivecase detection (RACD).RACD is generally understood to be triggered whenever a case isidentified by passive case detection. The response involves visiting thehousehold of the newly reported case and screening family members.Depending on program protocol, it may also involve screeningneighbors within a defined radius. RACD has been used or testedin Cambodia, China, India, Peru, Senegal, Swaziland, Tanzania,and Zambia. RACD can be resource intensive. Several studies raisequestions concerning whether and how RACD can be prioritized andtargeted effectively as case numbers continue to decline.MethodsSince September 2012 Zanzibar Malaria Elimination Programme(ZAMEP) has used RACD to limit onward transmission, reduce thelocal parasite reservoir, and gather data needed improve programeffectiveness. Zanzibar is one of very few malaria eliminationcontexts using a mobile technology system to support RACD.1Thissystem, called the Malaria Case Notification system (MCN) usesmobile software called Coconut Surveillance.Coconut Surveillance is free and open source software designed formalaria elimination. It includes an interactive SMS system for casenotification, a mobile software application designed to guide mobilecase workers through RACD, and an analytics software applicationdesigned for surveillance and response program managers.Data were collected in the Coconut Surveillance database formore than three years, beginning in September 2012. Reports weremonitored in real time and periodically to assess RACD responsetimes against protocol targets, case trends, case locations, and otherdata. Geographical Information System (GIS) software was usedto produce detailed maps of case households. Three independentassessments were conducted of various aspects of the malariasurveillance system.ResultsFrom September 2012 to December 2015, Coconut Surveillancehas helped malaria surveillance officers in Zanzibar respond tomore than 8,617 (84%) reported cases of malaria, complete nearly10,245 household visits, test more than 36,185 household members,and identify and treat 2,032 previously unknown cases. The averagenumber of RACD activities occurring within 48 hours increased from72% in 2013 to 89% in 2015. The number of household membersscreened during RACD also increased from 7,589 in 2013 to 14,987in 2015. Challenges included incomplete registers at health carefacilities, lack of transport, inadequate training for clinicians andsurveillance officers, and insufficient communication to the affectedcommunities.ConclusionsIn Zanzibar twenty malaria surveillance officers equipped withinexpensive Android tablets and motorbikes are keeping malariaprevalence at less than 1%. The effectiveness of the system mightbe enhanced by improving training for clinicians and surveillanceofficers, ensuring the availability of transportation for surveillanceofficers, and improving communications to the affected communities.These results suggest key considerations for applying this and similarsystems in other malaria elimination contexts

Using Mobile Technology to Help Eliminate Malaria in Zanzibar

Decision support systems for malaria elimination must support rapid response to contain outbreaks. The integrated mobile system in Zanzibar has been recognized as one of the most advanced in the world. The system consists of a simple facility-based case notification system that uses common feature phones, and a mobile application for Android tablet computers. The resulting system enables rapid response to new cases, helps to rapidly diagnose and treat secondary case, and provides high-quality data for identifying hot spots, trends, and transmission patterns. This presentation will review the history, technology, results, lessons-learned, and applicability to other contexts

Using Mobile Technology to Facilitate Reactive Case Detection of Malaria

ObjectiveThis presentation will share findings from more than three years ofusing mobile technology for reactive case detection (RACD) to helpeliminate malaria in a well-defined geographic area. It will reviewthe concepts of RACD, the application of mobile technology, lessonslearned from more than three years of application, and considerationsin applying this technology in other malaria elimination contexts.IntroductionZanzibar is comprised primarily of two large islands with apopulation of 1.3 million. Indoor Residual Spraying (IRS) campaigns,distribution of long-lasting insecticide treated bed nets (LLINs),and use of Rapid Diagnostic Tests (RDTs) have reduced Malariaprevalence from 39% in 2005 to less than 1% in 2011-2012. Asmalaria burden decreases, there is an increasing need to track andfollow up individual cases to contain transmission that could lead toresurgence. One method being used to achieve these aims is reactivecase detection (RACD).RACD is generally understood to be triggered whenever a case isidentified by passive case detection. The response involves visiting thehousehold of the newly reported case and screening family members.Depending on program protocol, it may also involve screeningneighbors within a defined radius. RACD has been used or testedin Cambodia, China, India, Peru, Senegal, Swaziland, Tanzania,and Zambia. RACD can be resource intensive. Several studies raisequestions concerning whether and how RACD can be prioritized andtargeted effectively as case numbers continue to decline.MethodsSince September 2012 Zanzibar Malaria Elimination Programme(ZAMEP) has used RACD to limit onward transmission, reduce thelocal parasite reservoir, and gather data needed improve programeffectiveness. Zanzibar is one of very few malaria eliminationcontexts using a mobile technology system to support RACD.1Thissystem, called the Malaria Case Notification system (MCN) usesmobile software called Coconut Surveillance.Coconut Surveillance is free and open source software designed formalaria elimination. It includes an interactive SMS system for casenotification, a mobile software application designed to guide mobilecase workers through RACD, and an analytics software applicationdesigned for surveillance and response program managers.Data were collected in the Coconut Surveillance database formore than three years, beginning in September 2012. Reports weremonitored in real time and periodically to assess RACD responsetimes against protocol targets, case trends, case locations, and otherdata. Geographical Information System (GIS) software was usedto produce detailed maps of case households. Three independentassessments were conducted of various aspects of the malariasurveillance system.ResultsFrom September 2012 to December 2015, Coconut Surveillancehas helped malaria surveillance officers in Zanzibar respond tomore than 8,617 (84%) reported cases of malaria, complete nearly10,245 household visits, test more than 36,185 household members,and identify and treat 2,032 previously unknown cases. The averagenumber of RACD activities occurring within 48 hours increased from72% in 2013 to 89% in 2015. The number of household membersscreened during RACD also increased from 7,589 in 2013 to 14,987in 2015. Challenges included incomplete registers at health carefacilities, lack of transport, inadequate training for clinicians andsurveillance officers, and insufficient communication to the affectedcommunities.ConclusionsIn Zanzibar twenty malaria surveillance officers equipped withinexpensive Android tablets and motorbikes are keeping malariaprevalence at less than 1%. The effectiveness of the system mightbe enhanced by improving training for clinicians and surveillanceofficers, ensuring the availability of transportation for surveillanceofficers, and improving communications to the affected communities.These results suggest key considerations for applying this and similarsystems in other malaria elimination contexts

Artemisinin combination therapy mass drug administration in a setting of low malaria endemicity: programmatic coverage and adherence during an observational study in Zanzibar

Abstract Background Mass drug administration (MDA) appears to be effective in reducing the risk of malaria parasitaemia. This study reports on programmatic coverage and compliance of MDA using artemisinin-based combination therapy (ACT) in four shehias (smallest administration unit) that had been identified as hotspots through Zanzibar’s malaria case notification surveillance system. Methods Mass drug administration was done in four shehias selected on the basis of: being an established malaria hot spot; having had mass screening and treatment (MSaT) 2–6 weeks previously; and exceeding the epidemic alert threshold of 5 cases within a week even after MSaT. Communities were sensitized and MDA was conducted using a house-to-house approach. All household members, except pregnant women and children aged less than 2 months, were provided with ACT medicine. Two weeks after the MDA campaign, a survey was undertaken to investigate completion of ACT doses. Results A total of 8816 [97.1% of eligible; 95% confidence interval (CI) 96.8–97.5] people received ACT. During post MDA surveys, 2009 people were interviewed: 90.2% reported having completed MDA doses; 1.9% started treatment but did not complete dosage; 4.7% did not take treatment; 2.0% were absent during MDA and 1.2% were ineligible (i.e. infants <2 months and pregnant women). Main reasons for failure to complete treatment were experience of side-effects and forgetting to take subsequent doses. Failure to take treatment was mainly due to fear of side-effects, reluctance due to lack of malaria symptoms and caregivers forgetting to give medication to children. Conclusion Mass drug administration for malaria was well accepted by communities at high risk of malaria in Zanzibar, with high participation and completion rates. Further work to investigate the potential of MDA in accelerating Zanzibar’s efforts towards malaria elimination should be pursued

Tracking a defined route for O2 migration in a dioxygen-activating diiron enzyme

For numerous enzymes reactive toward small gaseous compounds, growing evidence indicates that these substrates diffuse into active site pockets through defined pathways in the protein matrix. Toluene/o-xylene monooxygenase hydroxylase is a dioxygen-activating enzyme. Structural analysis suggests two possible pathways for dioxygen access through the α-subunit to the diiron center: a channel or a series of hydrophobic cavities. To distinguish which is utilized as the O2 migration pathway, the dimensions of the cavities and the channel were independently varied by site-directed mutagenesis and confirmed by X-ray crystallography. The rate constants for dioxygen access to the diiron center were derived from the formation rates of a peroxodiiron(III) intermediate, generated upon treatment of the diiron(II) enzyme with O2. This reaction depends on the concentration of dioxygen to the first order. Altering the dimensions of the cavities, but not the channel, changed the rate of dioxygen reactivity with the enzyme. These results strongly suggest that voids comprising the cavities in toluene/o-xylene monooxygenase hydroxylase are not artifacts of protein packing/folding, but rather programmed routes for dioxygen migration through the protein matrix. Because the cavities are not fully connected into the diiron active center in the enzyme resting state, conformational changes will be required to facilitate dioxygen access to the diiron center. We propose that such temporary opening and closing of the cavities may occur in all bacterial multicomponent monooxygenases to control O2 consumption for efficient catalysis. Our findings suggest that other gas-utilizing enzymes may employ similar structural features to effect substrate passage through a protein matrix.National Institute of General Medical Sciences (U.S.) (Grant Number GM032134)Henry & Camille Dreyfus Foundation (Faculty Start-Up award