171 research outputs found
Best foot forward, watching your step, jumping in with both feet, or sticking your foot in it? - the politics of researching academic viewpoints
This article presents our experiences of conducting research interviews with Australian academics, in order to reflect on the politics of researcher and participant positionality. In particular, we are interested in the ways that academic networks, hierarchies and cultures, together with mobility in the higher education sector, contribute to a complex discursive terrain in which researchers and participants alike must maintain vigilance about where they 'put their feet' in research interviews. We consider the implications for higher education research, arguing that the positionality of researchers and participants pervades and exceeds these specialised research situations.15 page(s
Design of Alkali-Activated Slag-Fly Ash Concrete Mixtures Using Machine Learning
So far, the alkali activated concrete has primarily focused on the effect of source material properties and ratio of mix proportions on the compressive strength development. A little research has focused on developing a standard mix design procedure for alkali activated concrete for a range of compressive strength grades. This study developed a standard mix design procedure for alkali activated slag‒fly ash (low calcium, class F) blended concrete using two machine learning techniques, Artificial Neural Networks (ANN) and Multivariate Adaptive Regression Spline (MARS). The algorithm for the predictive model for concrete mix design was developed using MATLAB programming environment by considering the five key input parameters; water/solid ratio, alkaline activator/binder ratio, Na-Silicate /NaOH ratio, fly ash/slag ratio and NaOH molarity. The targeted compressive strengths ranging from 25–45 MPa (3.63–6.53 ksi) at 28 days were achieved with laboratory testing, using the proposed machine learning mix design procedure. Thus, this tool has the capability to provide a novel approach for the design of slag-fly ash blended alkali activated concrete grades matching to the requirements of in-situ field constructions
Immunohistochemical detection of Claudin low breast cancer; which subcellular level to be assessed?
Objectives: Claudin low breast cancers are often high grade, triple negative tumours with poor prognosis. They are identified at genetic level and are not diagnosed routinely by immunohistochemistry. The objective was to determine the best subcellular level to detect Claudin low breast cancer by immunohistochemistry, in terms of their histopathological prognostic features.Methods: This cross sectional study included all archival breast cancer tissue collected up to December 2015 in our unit. Tissue microarrays (TMA) were constructed using 23 breast cancer cores with a diameter of 2mm, in each TMA. TMAs were immunohistochemically stained for Claudin 3 expression and was scored as; no staining=0, weak staining=1, moderate staining=2 and strong staining=3, separately for membrane, cytoplasmic and nuclear staining. A score <2 was considered Claudin low and analysed against the histopathological prognostic features of the breast cancer.Results: A total of 546 breast cancers were assessed. Claudin low expression was identified at cytoplasmic, membrane and nuclear level in 74.9%, 74.5% and 42% of breast cancers respectively. Low nuclear expression of Claudin 3 was associated with high grade (p=0.028), Nottingham Prognostic Index of >3.4 (p=0.028), ER and PR negative (p<0.001) and HER 2 negative (p=0.013) tumours while low membrane staining was associated with low grade (p=0.038), HER 2 negative (p<0.001) breast cancers. Low cytoplasmic staining was associated with HER 2 negative breast cancer only (p=0.002).Conclusions: Nuclear staining for Claudin should be assessed to identify Claudin low breast cancer by immunohistochemistry as it significantly associates with most of the Claudin low breast cancer characteristics
Green synthesis of sliver nanoparticles using different bacteria: Do the synthesized nanoparticles differ in their antimicrobial activity
Objectives: Biosynthesis and characterization of silver nanoparticles (AgNPs) from Escherichia coli,Acinetobacter baumannii and Staphylococcus aureus and determination of antimicrobial activityagainst selected pathogens.Methods: E. coli (ATCC 25922), A. baumannii (clinical strain), S. aureus (ATCC 25923) were culturedin nutrient broth medium and used for biosynthesis of AgNPs. AgNO3 concentration, pH, incubationtime and temperature were optimized for AgNP biosynthesis. Antimicrobial activity of the synthesizedAgNPs was studied using the well diffusion assay.Results: All the selected bacteria produced silver nanoparticles at alkaline pH when the concentrationof AgNO3 was greater than 0.3 g/L. The optimum reaction temperature was 60oC. UV-Visiblespectroscopy with a maximum absorbance of approximately 420 - 430 nm confirmed the presence ofAgNPs. AgNPs produced by S. aureus resulted in larger zone of inhibition (ZOI) against the selectedpathogens where AgNPs produced by E. coli showed comparatively smaller ZOI. Gram negativebacteria (E.coli, P. aeruginosa) were more sensitive to AgNPs compared to gram positive bacteria(Methicillin Resistant S. aureus, S. aureus) and fungal species (Candida albicans).Conclusion: AgNPs produced by S. aureus are the most effective among the tested AgNPs while E.coli produced the least effective AgNPs
Use of Gliricidia sepium as a Nurse Plant to Reforest Man-made Grasslands in the Knuckles Forest Reserve, Sri Lanka
Biodiversity richness and socially beneficial watershed services are high in the KnucklesForest Reserve. However, the lower montane forest patches on the eastern slopes of the KFRare highly fragmented mainly due to anthropogenic disturbances. If these forest fragments arenot connected in the near future, they will disappear from the landscape due to their lowregeneration rates. Native tree species when used for restoration of these lands faces manydifficulties due to various biotic and abiotic stresses including harsh microclimatic conditionsand infertile soils. Therefore, usage of a nurse plant will facilitate the growth of target speciesdue to creation of favourable microclimatic conditions. Gliricidia sepium has been used as ashade plant in Sri Lanka, since colonial times. More recently it has been used for indigenousfarming practices, soil stabilization, living fences and as fuel wood, animal forage, greenmanure. In our research we investigate the potential of G. sepium as a nurse plant to establishfour native tree species on man-made grasslands in central Sri Lanka. The study wasconducted on four blocks of grasslands. Four replicates of each of the three island sizes(small 4 m2, medium 16 m2, and large 64 m2) were created inside each block. One set ofislands in each block were planted with G. sepium stakes at 2 m intervals in a grid format.The other set of islands in each block was kept as a control without planting G. sepiumstakes. Seedlings of Macaranga indica, Bhesa ceylanica, Symplocos cochinchinensis andEugenia bracteata were planted randomly in islands with and without G. sepium stakes.After three months of establishment, the survival rate of G. sepium in the four blocks wasmore than 80% and the survival rate of the G. sepium was 20% higher in the small andmedium islands than the large islands. The mean number of sprouts per stake was more thaneight in medium and large islands and less than six in small islands. The mean survival ratewas higher (5.8%) and the mean growth rates was lower (0.006%) for all the four nativespecies with G. sepium than without G. sepium after three months of planting. G. sepiumincreased the survival rates of native species after three months of establishment due tofavourable microclimatic conditions created by them. However, growth rate of the nativespecies which were planted with G. sepium was lower probably due to interspecificcompetition. Therefore, G. sepium can be used as an effective nurse plant in initial phases ofreforestation programmes to increase the survival rates of native tree species on degradedsubmontane sites in Sri Lanka.
Human stomach microbiota: Effects on health and disease
The gut microbiota is a complex ecological community, consisting of trillions of microbes which include bacteria, viruses, fungi and protozoa. The stomach was previously considered as a sterile site uninhabited by microbes due to its hostile environmental conditions. Breaking this concept, Helicobacter pylori was the first pathogen reported to inhabit the stomach. Recent studies have suggested that the stomach harbours transient as well as certain commensal bacterial and fungal species. The five major microbial phyla in the stomach have been identified as Firmicutes, Bacteroidetes, Actinobacteria, Fusobacteria and Proteobacteria. The composition of gastric microbiota is dynamic and is affected by several factors. These include age group, dietary habits, medication use, inflammation of gastric mucosa and H. pylori colonization. Further, the role of host genetics has recently been studied in maintaining the stomach microbiota. Mutations in host genes may affect the host’s immune response towards commensal bacteria and reduce their number and diversity. The essential multiple roles of gut microorganisms include maintaining homeostasis in the gut, contributing to immune function and extraction of nutrients and energy from our diets. Loss of the normal balance between the gut microbiota and host has been associated with several abnormal conditions and disorders such as obesity, malnutrition, inflammatory bowel diseases (IBD), neurological disorders, and cancer. In the stomach, the interaction between H. pylori and the gastric microbiota can also influence gastric disÂease progression. Further studies should focus on addressing the role of gastric dysbiosis in health and disease. Identifying gastric microbiota is essential to understand how the gut microbiota and H. pylori affect health and disease.</p
TiO2 21 nm nanoparticles as a photocatalytic antimicrobial agent against Escherichia coli, Candida albicans and Methicillin resistant Staphylococcus aureus: A comparison
 Objectives: To determine and compare the antimicrobial activity of 21 nm TiO2 nanoparticles against Escherichia colii, Candida albicans and Methicillin resistant Staphylococcus aureus (MRSA).Methods: Titanium dioxide (TiO2) 21 nm anatase nanoparticles (13.9 g/l) were suspended in miliQ (MQ) water, sonicated (35 MHz for 1 hour) and autoclaved. Sterile glass petriplates were treated with TiO2 suspension or sterile MQ(control). Overnight cultures of E.coli MRSA and C. albicans were added to TiO2 coated plates and control plates and kept at room temperature.  Viable counts were obtained by spread plate method at 0 hours and 24 hours; before and after sunlight exposure for 30 minutes. Colony forming units (CFU) / ml was calculated to determine percentage reduction of CFU in presence of TiO2. Experiments were done in triplicates.Results: TiO2 nanoparticles demonstrated antimicrobial activity against E.coli, MRSA and C. albicans. Estimated percentage CFU reduction in E.coli (13±8.4), MRSA (12±6.6) and C. albicans (36±4.9 ) was observed at 0 hours of contact in the supernatant. The bactericidal effect was enhanced on exposure of the plates to sunlight. Estimated percentage CFU reductions are E. coli (46±7.9), MRSA (99±0.2 ) and C. albicans (99±0.4). The results for 24 hours were (95±1 ), (35±2.1 ) and (83±4 ) reduction for E. coli, MRSA and C. albicans respectively. When the 24 hour plates were exposed to sunlight (99±0.6), (99±0.6) and (99±0.2) reduction was seen for E.coli, MRSA and C. albicans respectively. Conclusion: Anatase 21 nm TiO2 nanoparticles show enhanced antimicrobial activity against the tested microbial strains following photoactivation by sunlight. Antimicrobial activity against three different types of microbial strains has varying effects
Three year naturalistic outcome study of panic disorder patients treated with paroxetine
BACKGROUND: This naturalistic open label follow-up study had three objectives: 1) To observe the course of illness in Panic Disorder patients receiving long-term versus intermediate-term paroxetine treatment 2) To compare the relapse rates and side-effect profile after long-term paroxetine treatment between patients with Panic Disorder and Panic Disorder with Agoraphobia. 3) To observe paroxetine's tolerability over a 24 month period. METHODS: 143 patients with panic disorder (PD), with or without agoraphobia, successfully finished a short-term (ie 12 week) trial of paroxetine treatment. All patients then continued to receive paroxetine maintenance therapy for a total of 12 months. At the end of this period, 72 of the patients chose to discontinue paroxetine pharmacotherapy and agreed to be monitored throughout a one year discontinuation follow-up phase. The remaining 71 patients continued on paroxetine for an additional 12 months and then were monitored, as in the first group, for another year while medication-free. The primary limitation of our study is that the subgroups of patients receiving 12 versus 24 months of maintenance paroxetine therapy were selected according to individual patient preference and therefore were not assigned in a randomized manner. RESULTS: Only 21 of 143 patients (14%) relapsed during the one year medication discontinuation follow-up phase. There were no significant differences in relapse rates between the patients who received intermediate-term (up to 12 months) paroxetine and those who chose the long-term course (24 month paroxetine treatment). 43 patients (30.1%) reported sexual dysfunction. The patients exhibited an average weight gain of 5.06 kg. All patients who eventually relapsed demonstrated significantly greater weight increase (7.3 kg) during the treatment phase. CONCLUSIONS: The extension of paroxetine maintenance treatment from 12 to 24 months did not seem to further decrease the risk of relapse after medication discontinuation. Twenty-four month paroxetine treatment is accompanied by sexual side effects and weight gain similar to those observed in twelve month treatment
An Integrated Microfluidic Device for Monitoring Changes in Nitric Oxide Production in Single T-Lymphocyte (Jurkat) Cells
A considerable amount of attention has been focused on the analysis of single cells in an effort to better understand cell heterogeneity in cancer and neurodegenerative diseases. Although microfluidic devices have several advantages for single cell analysis, few papers have actually demonstrated the ability of these devices to monitor chemical changes in perturbed biological systems. In this paper, a new microfluidic channel manifold is described that integrates cell transport, lysis, injection, electrophoretic separation, and fluorescence detection into a single device, making it possible to analyze individual cells at a rate of 10 cells/min in an automated fashion. The system was employed to measure nitric oxide (NO) production in single T-lymphocytes (Jurkat cells) using a fluorescent marker, 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA). The cells were also labeled with 6-carboxyfluorescein diacetate (6-CFDA) as an internal standard. The NO production by control cells was compared to that of cells stimulated using lipopolysaccharide (LPS), which is known to cause the expression of inducible nitric oxide synthase (iNOS) in immune-type cells. Statistical analysis of the resulting electropherograms from a population of cells indicated a twofold increase in NO production in the induced cells. These results compare nicely to a recently published bulk cell analysis of NO
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