113 research outputs found
Performance of Acid Leached Rice Husk Ash (ARHA) in Mortar
RHA is one the most available agricultural wastes in rice producing countries. Roughly of 20% of the total amount of paddy is husk which giving an annual total production of 120 Mtons which causes disposal problem due to low commercial interest and uses. The presence of metal impurities (Na2O and K2O) in non-treated RHA that incorporating in concrete can trigger alkali reaction in harden concrete. In order to overcome the issue, hydrochloric acid as the leaching agent for acid leaching treatment on RHA effectively removed metallic impurities from the RHA. In this study, ARHA was prepared by acid leaching treatment in order that the end product conformed to the engineering standards in terms of chemical and morphological properties. There are total of 3 proposed acid leaching parameters on RHA (1 M, 0.1 M and 0.01 M HCl leaching treatment with the duration of 2 days) prior to combustion at 800oC for 2 hours. The chemical properties and morphology study of the ARHA would be firstly characterized base on the x-ray fluorescent (XRF), x-ray diffraction (XRD), particle size analyzer, loss on ignition (LOI) and BET analyzer. 0.1 M of HCl leaching treatment RHA (ARHA2) prior to combustion at 800oC for 2 hours effectively removed impurities and produced > 90 % of pure amorphous silica with high surface area and pore volume. Hence, the effects of incorporating ARHA2 as partial replacement (2.5 %, 5 %, 7.5 %, and 10 %) of cement were investigated. The compressive strength, ultrasonic pulse velocity (UPV), porosity, gas permeability and the water absorption of ARHA mortar were determined to identify the characteristics of AHRA mortar. The results show that the replacement 10 % of ARHA into the mortar gave a positive result, it improved 29% of compressive strength compared to the control mix. In term of durability properties, there was approximate 2.2 % reduction in the total porosity as the replacement level of ARHA2 increased from 0 % to 10 % of total binder in the mortar
Microdroplets Advancement in Newtonian and Non- Newtonian Microfluidic Multiphase System
With recent advancement in droplet microfluidics for both microdroplet encapsulation and fission, it is of paramount importance to understand the flow physics for both Newtonian and non-Newtonian fluids in microdroplet encapsulation and fission as the development of the field is approaching to its maturity. The chapter aims to review and discuss the fluid flow behavior of the multiphase system, mathematical models as well as the fundamental phenomena driving force of microdroplet encapsulation and fission multiphase system. Together, the recent advances in technologies that enable fabrication and application of droplets encapsulation and fission from both Newtonian and non-Newtonian microfluidic multiphase system will be reviewed as well
Development of Hybrid Polymeric Polyerthersulfone (PES) Membrane Incorporated with Powdered Activated Carbon (PAC) for Palm Oil Mill Effluent (POME) Treatment
The development of water treatment system to produce low cost & high quality effluent has become extremely important nowadays. Since year 1960, membrane technology has transformed from laboratory stage to industrial applications stage. The development of newer membrane modules in recent years helps the membrane industry growth rapidly, but the technology is still not so universal due to membrane fouling issue. Additional of PAC directly into the treatment system has proven to be a promising strategy to reduce membrane fouling and improve efficiency of the system. However, there are also drawbacks caused by excessive PAC within a treatment system. In this study, the potential of integrating the PAC into PES membrane was evaluated and its performance was assessed. The result shows that the PAC integrated membrane has higher permeation rate, which is 231 L/m2.hr compare to the one without PAC integrated membrane, which only has 89 L/m2.hr. In addition, PAC integrated membrane was able to achieve up to 81% and 67% removal rate, compared to the one without PAC integrated which only can remove 10% and 35% of COD and color respectively. Besides, the structural property of the membranes was observed using scanning electron microscopy (SEM). The results showed a trend where the membrane with higher concentration of PAC integrated will have better performance in both pollutant removal ability as well as the membrane fouling control
DESIGN AND IMPLEMENTATION THE LLC RESONANT TRANSFORMER*
Abstract The energy and dc to dc conversion voltage waveform of the LLC resonant transformer are required to achieve optimal working condition of the resonant region frequency. To meet this requirement, a reliable and precise instrument is needed to scan the resonant cure of the LLC resonant transformer such that its output power performance can meet the required specification. In this paper, the design and model of a new LLC resonant transformer deployed in NSRRC is described. This LLC resonant transformer is capable of delivering energy conversion with high efficiency performance, which is better than traditional transformer, and the voltage transfer ratio is depended on the resonant Frequency. Using the simulation circuit model to develop a power converter of it is also included in the design of this new LLC resonant transformer. It has been tested and proven to be working well in power conversion with excellent efficiency and performance
The giant freshwater prawn Macrobrachium rosenbergii alters background colour preference after metamorphosis from larvae to post larvae: In association with nature of photo taxis
The giant freshwater prawn Macrobrachium rosenbergii larvae have apposition eyes and are positively phototactic, whereas the postlarvae (PL) have superposition eyes and are negatively phototactic. M. rosenbergii has colour vision as early as larval stage. We discovered that M. rosenbergii alters background colour preference after metamorphosis from larvae to PL in association with nature of phototaxis. The test circular glass aquaria covered with a pair of two‐colour papers contained with a group of 100 larvae or 20 Pl, and the number of individuals in each colour background was recorded five times for each colour pair. The background colours tested were light blue, green, yellow, red, white and black. The numbers of larvae or PL in each colour background of different pairs were analysed by the Thurstone's law of comparative judgment. In the larvae, significant bias towards yellow was evident. In the PL, of the four pairings of black with other colours, all biased to black. The mean z‐scores were highest for yellow in the larvae, and for black in the PL. To determine the possible background brightness preference of the larvae and PL, six different colour backgrounds were presented in pairs. The larvae significantly preferred light blue over dark blue, white over yellow and white over black. The PL exhibited reversed preference. The relationship between z‐scores and light reflectance levels of five colour papers was significantly positive in the larvae and negative in the PL. The observed background colour preference was probably due to relative brightness rather than chromaticity difference
Clinical phenotypes of COPD and health-related quality of life: a cross-sectional study
The Spanish COPD guideline (GesEPOC) classifies COPD into four clinical phenotypes based on the exacerbation frequency and dominant clinical manifestations. In this study, we compared the disease-specific health-related quality of life (HRQoL) of patients with different clinical phenotypes
Predicting the catalytic sites of isopenicillin N synthase (IPNS) related non-haem iron-dependent oxygenases and oxidases (NHIDOX) through a structural superimposition and molecular docking approach
Isopenicillin N synthase (IPNS) related Non-haem iron-dependent oxygenases and oxidases (NHIDOX) demonstrated a striking structural conservativeness, even with low protein sequence homology. It is evident that these enzymes have an architecturally similar catalytic centre with active ligands lining the reactive pocket. Deacetoxycephalosporin C synthase (DAOCS), isopenicillin N synthase (IPNS), deacetylcephalosporin C synthase (DACS), clavaminate synthase 1 and 2 (CAS1 and 2) are important bacterial enzymes that catalyze the formation of β-lactam antibiotics belonging to this enzyme family. Most plant enzyme members within this subfamily namely flavonol synthase (FLS), leucoanthocyanidin dioxygenase (LDOX), anthocyanidin synthase (ANS), 1-aminocyclopropane-1-carboxylic acid oxidase (ACCO), gibberellin 20-oxidase (G20O), desacetoxyvindoline-4-hydroxylase (D4H), flavanone 3β-hydroxylase (F3H), and hyoscyamine 6β-hydroxylase (H6H) are involved in catalyzing the biosyntheses of plant secondary metabolites. With the advancement of protein structural analysis software, it is possible to predict the catalytic sites of protein that shared a structural resemblance. By exploiting the superimposition model of DAOCS-IPNS, DAOCS-IPNS-CAS, G20O-LDOX, FLS-LDOX, ACCO-LDOX, D4H-LDOX, F3H-LDOX and H6H-LDOX model; a computational protocol for predicting the catalytic sites of proteins is now made available. This study shows that without the crystallized or nuclear magnetic resonance (NMR) structures of most NHIDOX enzyme, the plausible catalytic sites of protein can be forecasted using this structural bioinformatics approach.Keywords: Enzyme, catalytic sites, isopenicillin N synthase, ligand
FOXO-regulated DEAF1 controls muscle regeneration through autophagy
The commonality between various muscle diseases is the loss of muscle mass, function, and regeneration, which severely restricts mobility and impairs the quality of life. With muscle stem cells (MuSCs) playing a key role in facilitating muscle repair, targeting regulators of muscle regeneration has been shown to be a promising therapeutic approach to repair muscles. However, the underlying molecular mechanisms driving muscle regeneration are complex and poorly understood. Here, we identified a new regulator of muscle regeneration, Deaf1 (Deformed epidermal autoregulatory factor-1) – a transcriptional factor downstream of foxo signaling. We showed that Deaf1 is transcriptionally repressed by FOXOs and that DEAF1 targets to Pik3c3 and Atg16l1 promoter regions and suppresses their expression. Deaf1 depletion therefore induces macroautophagy/autophagy, which in turn blocks MuSC survival and differentiation. In contrast, Deaf1 overexpression inactivates autophagy in MuSCs, leading to increased protein aggregation and cell death. The fact that Deaf1 depletion and its overexpression both lead to defects in muscle regeneration highlights the importance of fine tuning DEAF1-regulated autophagy during muscle regeneration. We further showed that Deaf1 expression is altered in aging and cachectic MuSCs. Manipulation of Deaf1 expression can attenuate muscle atrophy and restore muscle regeneration in aged mice or mice with cachectic cancers. Together, our findings unveil an evolutionarily conserved role for DEAF1 in muscle regeneration, providing insights into the development of new therapeutic strategies against muscle atrophy
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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