Development and performance of iron based oxygen carriers containing calcium ferrites for chemical looping combustion and production of hydrogen

Chemical looping combustion (CLC) is a cyclic process in which an oxygen carrier (OC), is firstly reduced by a fuel, e.g. syngas, and then oxidised in air to produce heat. If the OC is Fe2O3, the oxidation can take place in steam to produce hydrogen, i.e. chemical looping hydrogen production (CLH). This paper presents an investigation of CaO modified Fe2O3 OCs for CLC and CLH. The performance of the mechanically mixed OCs were examined in a thermogravimetric analyser and a fluidised bed. It was found that the addition of CaO gives cyclic stability and additional capacity to produce hydrogen via CLH, at the expense of reduced oxygen carrying capacity for CLC, owing to the formation of calcium ferrites, such as Ca2Fe2O5.The authors would like to thank Prof. Clare Grey for her invaluable help in the XRD analysis and Z. Saracevic for support in operating the gas adsorption analyser. This work was supported by the Engineering and Physical Sciences Research Council (EPSRC grant EP/I070912/1). The first author is grateful to IDB (Islamic Development Bank) - Cambridge International Scholarship body for financial support for PhD study. W. L acknowledges funding from the National Research Foundation (NRF), Prime Minister’s Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) programme.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.ijhydene.2015.11.06

Microbial predation accelerates granulation and modulates microbial community composition.

BackgroundBacterial communities are responsible for biological nutrient removal and flocculation in engineered systems such as activated floccular sludge. Predators such as bacteriophage and protozoa exert significant predation pressure and cause bacterial mortality within these communities. However, the roles of bacteriophage and protozoan predation in impacting granulation process remain limited. Recent studies hypothesised that protozoa, particularly sessile ciliates, could have an important role in granulation as these ciliates were often observed in high abundance on surfaces of granules. Bacteriophages were hypothesized to contribute to granular stability through bacteriophage-mediated extracellular DNA release by lysing bacterial cells. This current study investigated the bacteriophage and protozoan communities throughout the granulation process. In addition, the importance of protozoan predation during granulation was also determined through chemical killing of protozoa in the floccular sludge.ResultsFour independent bioreactors seeded with activated floccular sludge were operated for aerobic granulation for 11 weeks. Changes in the phage, protozoa and bacterial communities were characterized throughout the granulation process. The filamentous phage, Inoviridae, increased in abundance at the initiation phase of granulation. However, the abundance shifted towards lytic phages during the maturation phase. In contrast, the abundance and diversity of protozoa decreased initially, possibly due to the reduction in settling time and subsequent washout. Upon the formation of granules, ciliated protozoa from the class Oligohymenophorea were the dominant group of protozoa based on metacommunity analysis. These protozoa had a strong, positive-correlation with the initial formation of compact aggregates prior to granule development. Furthermore, chemical inhibition of these ciliates in the floccular sludge delayed the initiation of granule formation. Analysis of the bacterial communities in the thiram treated sludge demonstrated that the recovery of 'Candidatus Accumulibacter' was positively correlated with the formation of compact aggregates and granules.ConclusionPredation by bacteriophage and protozoa were positively correlated with the formation of aerobic granules. Increases in Inoviridae abundance suggested that filamentous phages may promote the structural formation of granules. Initiation of granules formation was delayed due to an absence of protozoa after chemical treatment. The presence of 'Candidatus Accumulibacter' was necessary for the formation of granules in the absence of protozoa

Improving hydrogen yields, and hydrogen: Steam ratio in the chemical looping production of hydrogen using Ca<inf>2</inf>Fe<inf>2</inf>O<inf>5</inf>

A thermodynamic property of Ca2Fe2O5 was exploited to improve the efficiency of the steam-iron process to produce hydrogen. The ability of reduced Ca2Fe2O5 to convert a higher fraction of steam to hydrogen than chemically unmodified Fe was demonstrated in a packed bed. At 1123 K, the use of Ca2Fe2O5 achieved an equilibrium conversion of steam to hydrogen of 75%, in agreement with predicted thermodynamics and substantially higher than that theoretically achievable by iron oxide, viz. 62%. Furthermore, in Ca2Fe2O5, the full oxidation from Fe(0) to Fe(III) can be utilised for hydrogen production – an improvement from the Fe to Fe3O4 transition for unmodified iron. Thermodynamic considerations demonstrated in this study allow for the rational design of oxygen carriers in the future. Modifications of reactors to capitalise on this new material are discussed.Dr Matthew T. Dunstan is acknowledged for help with the XRD analysis. M.S.C.C acknowledges financial support from an EPSRC Doctoral Training Grant. W.L and Y.Y acknowledge funding from the National Research Foundation (NRF), Prime Minister’s Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) programme.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.cej.2016.03.13

Amplification of real-time high resolution melting analysis PCR method for polycystic kidney disease (PKD) gene mutations in autosomal dominant polycystic kidney disease patients

PKD1 and PKD2 are the two genes responsible for the development of autosomal dominant polycystic kidney disease (ADPKD). PKD1 gene mutations accounts for ≈85% of all ADPKD cases, while the remaining ≈15% of cases is caused by mutations in the PKD2 gene. Genotyping for PKD1 and PKD2 mutations was usually identified using conventional polymerase chain reaction (PCR) or PCR-single stranded conformation polymorphisms (SSCP) methods. In this study, we assessed the usefulness of eight common primers amplifying the respective genes in real-time high resolution melting analysis PCR (real-time HRMA PCR) in terms of time, cost and sensitivity with respect to PCR-SSCP method. We found that case sample can easily be differentiated from control sample by melting curve profile difference, although a primer was found to be less useful. We concluded that real-time HRMA PCR is a rapid and sensitive method to categorize samples based on the melting curve profiles with comparable sensitivity to conventional PCR-SSCP.Key words: Autosomal dominant polycystic kidney disease (ADPKD), real-time PCR, high resolution melting analysis, PKD1, PKD2

Forest Trees in Human Modified Landscapes: Ecological and Genetic Drivers of Recruitment Failure in Dysoxylum malabaricum (Meliaceae)

Tropical agro-forest landscapes are global priority areas for biodiversity conservation. Little is known about the ability of these landscapes to sustain large late successional forest trees upon which much forest biodiversity depends. These landscapes are subject to fragmentation and additional habitat degradation which may limit tree recruitment and thus compromise numerous ecosystem services including carbon storage and timber production. Dysoxylum malabaricum is a large canopy tree species in the Meliaceae, a family including many important tropical timber trees. This species is found in highly fragmented forest patches within a complex agro-forest landscape of the Western Ghats biodiversity hot spot, South India. In this paper we combined a molecular assessment of inbreeding with ecological and demographic data to explore the multiple threats to recruitment of this tree species. An evaluation of inbreeding, using eleven microsatellite loci in 297 nursery-reared seedlings collected form low and high density forest patches embedded in an agro-forest matrix, shows that mating between related individuals in low density patches leads to reduced seedling performance. By quantifying habitat degradation and tree recruitment within these forest patches we show that increasing canopy openness and the increased abundance of pioneer tree species lead to a general decline in the suitability of forest patches for the recruitment of D. malabaricum. We conclude that elevated inbreeding due to reduced adult tree density coupled with increased degradation of forest patches, limit the recruitment of this rare late successional tree species. Management strategies which maintain canopy cover and enhance local densities of adult trees in agro-forest mosaics will be required to ensure D. malabaricum persists in these landscapes. Our study highlights the need for a holistic understanding of the incipient processes that threaten populations of many important and rare tropical tree species in human dominated agro-forest landscapes

“It feels like medically promoted disordered eating”: The psychosocial impact of gestational diabetes mellitus in the perinatal period

Background The global prevalence of gestational diabetes mellitus (GDM) is increasing, and it can significantly impact women’s psychosocial outcomes in the perinatal period. The aim of this study was to explore the psychosocial impacts including experiences of support for women with GDM in the antenatal and postnatal period. Methods Semi-structured individual interviews were conducted with women (n = 33) living in the UK, who were either pregnant and recently diagnosed with GDM or had a previous GDM diagnosis within the past three years. Interviews were recorded, transcribed, and analysed using reflexive thematic analysis. Findings Analysis revealed six themes: 1. Diagnostic related frustration; 2. Impact on mental health; 3. The medicalisation of eating; 4. Losing agency to gain control; 5. Sourcing networks of support; 6. Current pregnancy; and future reproductive health. Each theme provides a unique insight into the experiences and psychological strain associated with GDM. From confusion and frustration at diagnosis, to the profound knock-on impact a diagnosis, associated lifestyle changes and medical appointments had on women’s mental health, and the perceived medicalisation of their eating behaviours and patterns. Conclusion Given the increasing prevalence of GDM and its wide-ranging psychosocial impacts, this study emphasises the need for healthcare professionals to consider the potential implications of GDM on women’s psychosocial outcome, and to consider alternative support options outside of the medical system, such as peer support

Large-scale air mass characteristics observed over the remote tropical Pacific Ocean during March-April 1999: Results from PEM-Tropics B field experiment

Eighteen long-range flights over the Pacific Ocean between 38° S to 20° N and 166° E to 90° W were made by the NASA DC-8 aircraft during the NASA Pacific Exploratory Mission (PEM) Tropics B conducted from March 6 to April 18, 1999. Two lidar systems were flown on the DC-8 to remotely measure vertical profiles of ozone (O3), water vapor (H2O), aerosols, and clouds from near the surface to the upper troposphere along their flight track. In situ measurements of a wide range of gases and aerosols were made on the DC-8 for comprehensive characterization of the air and for correlation with the lidar remote measurements. The transition from northeasterly flow of Northern Hemispheric (NH) air on the northern side of the Intertropical Convergence Zone (ITCZ) to generally easterly flow of Southern Hemispheric (SH) air south of the ITCZ was accompanied by a significant decrease in O3, carbon monoxide, hydrocarbons, and aerosols and an increase in H2O. Trajectory analyses indicate that air north of the ITCZ came from Asia and/or the United States, while the air south of the ITCZ had a long residence time over the Pacific, perhaps originating over South America several weeks earlier. Air south of the South Pacific Convergence Zone (SPCZ) came rapidly from the west originating over Australia or Africa. This air had enhanced O3 and aerosols and an associated decrease in H2O. Average latitudinal and longitudinal distributions of O3 and H2O were constructed from the remote and in situ O3 and H2O data, and these distributions are compared with results from PEM-Tropics A conducted in August-October 1996. During PEM-Tropics B, low O3 air was found in the SH across the entire Pacific Basin at low latitudes. This was in strong contrast to the photochemically enhanced O3 levels found across the central and eastern Pacific low latitudes during PEM-Tropics A. Nine air mass types were identified for PEM-Tropics B based on their O3, aerosols, clouds, and potential vorticity characteristics. The data from each flight were binned by altitude according to air mass type, and these results showed the relative observational frequency of the different air masses as a function of altitude in seven regions over the Pacific. The average chemical composition of the major air mass types was determined from in situ measurements in the NH and SH, and these results provided insight into the origin, lifetime, and chemistry of the air in these regions. Copyright 2001 by the American Geophysical Union

The (un)controlled body: A grounded theory analysis to conceptualise stigma for women with gestational diabetes mellitus

Health-related stigma is associated with adverse outcomes including depression, stress, and reduced engagement in health behaviours which are particularly harmful in pregnancy and postpartum. Women with gestational diabetes mellitus (GDM) report negative psychosocial experiences and may be at risk of stigma related to the condition. We aimed to understand women’s experiences of GDM-specific stigma. Individual interviews were conducted with n=53 women living in the UK with current or past (within four years) GDM. Grounded theory methodology was used to analyse the data. Four themes were identified: 1. Preconceptions and misconceptions; 2. Locating, regaining, and negotiating agency; 3. Tension about and resisting the dominant discourse of stigma; and 4. Reclaiming control over the body. GDM-specific stigma was diverse and far reaching and may have broader implications for perinatal mental health and postnatal wellbeing. It is pertinent to investigate possible prospective associations between GDMspecific stigma and biomedical and mental health outcomes

Acute Toxicity Study and Hepatocurative Effect of Aqueous Stem Bark Extract of Parkia Biglobosa in Wister albino Rats

Parkia biglobosa plant is widely is used in folk medicinal practices to treat and/or manage various diseases including diabetes, malaria, diarrhea and pains. The current research seek to establish the toxicity profile and hepatocurative ability of aqueous stem bark extract of the plant. Twelve (12) rats were used for Oral LD50 determination, and were grouped into four (4) groups of three rats (3) each. The first three groups were administered with 10 mg/kg, 100 mg/kg and 1000 mg/kg body weight of the extract respectively, while the last group was subdivided into three groups of one rat each and were administered with 2500mg/kg, 3500mg/kg and 5000mg/kg body weight of the extract respectively. For the hepatocurative studies, twenty five (25) experimental rats were divided into five groups of five (5) rats each. Group I served as normal rats, Group II served as test Control while Groups III to V were induced with liver damage and administered with 50mg/kg, 100mg/kg and 150mg/kg of the extract respectively. The LD50 was found to be greater than 5000mg/kg, while phytochemical screening revealed the presence of Flavanoids, Glycosides, Tanins, Saponins, Steroids and Phenols, with the absence of Anthraquinones. For the hepatocurative study, a significant (p&lt;0.0.5) increase in serum albumin and liver enzymes (AST, ALT and ALP) was observed in test control compared to normal control. Upon administration of the extract, a significant (p&lt;0.0.5) fall in Albumin, AST, ALT and ALP was recorded in a dose dependent pattern. No significant difference (p&gt;0.05) was observed between groups in total protein, direct and total bilirubin. The research concludes that the extract is practically non-toxic and possess strong hepatocurative ability which might be due to the phytochemicals present. Keywords: Acute toxiicity; CCl4; Liver; P. biglobosa; Phytochemical and wistar rats. DOI: 10.7176/JNSR/13-16-04 Publication date:September 30th 202