Use of Vietnamese rice husk ash for the production of sodium silicate as the activator for alkali-activated binders

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Geopolymer and Alkali-Activated Binders (AAB) has recently emerged as a new, green material with the potential to replace Portland cement in several applications. They can reduce the CO2 footprint of concrete by up to 80% and this is in addition to being more durable in certain aggressive environments. However, commercial alkaline activators contribute significantly to the cost and CO2 footprint of AAB concrete mixes. This research investigates the production of a low cost, low environmental impact sodium silicate solution (waterglass) from Rice Husk Ash (RHA) and more specifically RHA from Vietnam. A hydrothermal process for the dissolution of RHA in sodium hydroxide solution was developed. Sodium hydroxide solution concentration, process temperature and duration were studied. Optimised procedure parameters were found to be: NaOH concentration 3M, heating temperature 80 °C and heating duration 3h. The obtained solution was used for the production of AAB mortar made with a blend of fly ash and ground granulated blast furnace slag. Obtained compressive strength of mortar was in the range of 60 MPa at 28 days, matching the strength obtained from control samples produced with commercially available activators. Microstructural investigation (isothermal calorimetry, infrared spectroscopy, X-ray diffraction and thermogravimetric analysis) on pastes confirmed the equivalence between the solution produced with the optimised method and commercially available options. Cost analysis indicated that the proposed method could allow a reduction of almost 55% of the cost for the activation of AAB. Results from a simplified preliminary environmental analysis suggested increased sustainability of the RHA-derived solution when compared with commercially available waterglass.This research is funded by National University of Civil Engineering (NUCE) under grant number 108-2018/KHXD-TĐ. The authors also gratefully acknowledge the financial support provided by the National Foundation for Science and Technology Development- Vietnam (NAFOSTED); Queen’s University Belfast and the National University of Civil Engineering for sponsoring Dr Kien Tong’s partnership study programme. The Authors would also like to thank Dr Le Trung Thanh and Dr Bui Danh Dai for their guidance and valuable discussions; Dr Mark Russell for his assistance in the characterisation of both raw materials and reacted samples. The Authors are also grateful to Angkor Bio Cogen Co. Ltd., Cambodia, for their useful information on burning technologies available and information on power plants currently using rice hulls

Theoretical studies on the photophysical properties of luminescent pincer gold(III) arylacetylide complexes: the role of π-conjugation at the C-deprotonated [C^N^C] ligand

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Comparison of effects of sleeve gastrectomy, duodenal-jejunal bypass and ileal transposition for type II diabetes

Oral Presentations: OS9 - Surgery for Diabetes: no. OS9.02INTRODUCTION: Sleeve gastrectomy (SG), duodenal jejuna bypass (DJB) and ileal transposition (IT) have been reported to be effective for the treatment of T2DM. OBJECTIVES: It is unknown which procedure has a stronger anti-diabetic effect. The purpose of this study was to compare the effectiveness of these novel procedures METHODS: SG, DJB, IT and sham operation of each procedure were performed in 10-12 weeks old Goto-Kakizaki rats, a spontaneous non-obese model of T2DM. The glucose homeostasis effect was evaluated by measuring fasting glucose (FBG) and glycosylated haemoglobin (HbA1c). Gut hormonal profiles and lipid absorption were also examined. Rats were observed for 1 year. RESULTS: All three procedures had significant lower FBG when compared to the respective sham groups. DJB and IT had lower FBG than SG (SG vs DJB, p=0.023; SG vs IT, p=0.009) whereas DJB and IT had a similar FBG level, p=0.678. For HbA1c, all procedures had lower levels than the respective sham groups, p<0.001. The HbA1c of SG rebounded on 8th week whereas HbA1c of DJB and IT remained at low level. SG had a significant higher HbA1c level than DJB and IT, p<0.001 while DJB and IT had a similar level, p=0.685. GLP-1 and PYY were raised in DJB and IT whereas GIP level increased in DJB. All three procedures have different lipid absorption profile. CONCLUSION: SG, DJB and IT all had anti-diabetic effect. DJB and IT had more potent anti-diabetic effect than SG. Each procedure has different effects on metabolic diseases and their clinic application deserve individual consideration.published_or_final_versio

Comparison of effects of sleeve gastrectomy, duodenal-jejunal bypass and ileal transposition for the treatment of type II diabetes

This journal suppl. entitled: 2014 DDW AbstractThe SSAT’s 55th Annual Meeting took place during Digestive Disease Week 2014SSAT Poster Session (8215) - Stomach: Basic (I)BACKGROUND: Sleeve gastrectomy (SG), duodenal jejunal bypass (DJB) and ileal transposition (IT) have been reported to be effective for the treatment of T2DM. It is unknown which procedure has a stronger anti-diabetic effect. The purpose of this study was to compare the effectiveness of these novel procedures METHODS: SG, DJB, IT and ...postprin

The interplay between fluorescence and phosphorescence with luminescent gold(i) and gold(iii) complexes bearing heterocyclic arylacetylide ligands

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An exploration of parents’ preferences for foot care in juvenile idiopathic arthritis: a possible role for the discrete choice experiment

Background: An increased awareness of patients’ and parents’ care preferences regarding foot care is desirable from a clinical perspective as such information may be utilised to optimise care delivery. The aim of this study was to examine parents’ preferences for, and valuations of foot care and foot-related outcomes in juvenile idiopathic arthritis (JIA).&lt;p&gt;&lt;/p&gt; Methods: A discrete choice experiment (DCE) incorporating willingness-to-pay (WTP) questions was conducted by surveying 42 parents of children with JIA who were enrolled in a randomised-controlled trial of multidisciplinary foot care at a single UK paediatric rheumatology outpatients department. Attributes explored were: levels of pain; mobility; ability to perform activities of daily living (ADL); waiting time; referral route; and footwear. The DCE was administered at trial baseline. DCE data were analysed using a multinomial-logit-regression model to estimate preferences and relative importance of attributes of foot care. A stated-preference WTP question was presented to estimate parents’ monetary valuation of health and service improvements.&lt;p&gt;&lt;/p&gt; Results: Every attribute in the DCE was statistically significant (p &#60; 0.01) except that of cost (p = 0.118), suggesting that all attributes, except cost, have an impact on parents’ preferences for foot care for their child. The magnitudes of the coefficients indicate that the strength of preference for each attribute was (in descending order): improved ability to perform ADL, reductions in foot pain, improved mobility, improved ability to wear desired footwear, multidisciplinary foot care route, and reduced waiting time. Parents’ estimated mean annual WTP for a multidisciplinary foot care service was £1,119.05.&lt;p&gt;&lt;/p&gt; Conclusions: In terms of foot care service provision for children with JIA, parents appear to prefer improvements in health outcomes over non-health outcomes and service process attributes. Cost was relatively less important than other attributes suggesting that it does not appear to impact on parents’ preferences.&lt;p&gt;&lt;/p&gt

Horizontal DNA transfer mechanisms of bacteria as weapons of intragenomic conflict

Horizontal DNA transfer (HDT) is a pervasive mechanism of diversification in many microbial species, but its primary evolutionary role remains controversial. Much recent research has emphasised the adaptive benefit of acquiring novel DNA, but here we argue instead that intragenomic conflict provides a coherent framework for understanding the evolutionary origins of HDT. To test this hypothesis, we developed a mathematical model of a clonally descended bacterial population undergoing HDT through transmission of mobile genetic elements (MGEs) and genetic transformation. Including the known bias of transformation toward the acquisition of shorter alleles into the model suggested it could be an effective means of counteracting the spread of MGEs. Both constitutive and transient competence for transformation were found to provide an effective defence against parasitic MGEs; transient competence could also be effective at permitting the selective spread of MGEs conferring a benefit on their host bacterium. The coordination of transient competence with cell-cell killing, observed in multiple species, was found to result in synergistic blocking of MGE transmission through releasing genomic DNA for homologous recombination while simultaneously reducing horizontal MGE spread by lowering the local cell density. To evaluate the feasibility of the functions suggested by the modelling analysis, we analysed genomic data from longitudinal sampling of individuals carrying Streptococcus pneumoniae. This revealed the frequent within-host coexistence of clonally descended cells that differed in their MGE infection status, a necessary condition for the proposed mechanism to operate. Additionally, we found multiple examples of MGEs inhibiting transformation through integrative disruption of genes encoding the competence machinery across many species, providing evidence of an ongoing "arms race." Reduced rates of transformation have also been observed in cells infected by MGEs that reduce the concentration of extracellular DNA through secretion of DNases. Simulations predicted that either mechanism of limiting transformation would benefit individual MGEs, but also that this tactic's effectiveness was limited by competition with other MGEs coinfecting the same cell. A further observed behaviour we hypothesised to reduce elimination by transformation was MGE activation when cells become competent. Our model predicted that this response was effective at counteracting transformation independently of competing MGEs. Therefore, this framework is able to explain both common properties of MGEs, and the seemingly paradoxical bacterial behaviours of transformation and cell-cell killing within clonally related populations, as the consequences of intragenomic conflict between self-replicating chromosomes and parasitic MGEs. The antagonistic nature of the different mechanisms of HDT over short timescales means their contribution to bacterial evolution is likely to be substantially greater than previously appreciated