Comparative study on indoor fungi growth incorporated with different antifungal and wall finishings

Indoor air quality is important to the health and comfort of building occupants. There are many sources of pollutants that can be found in the building. One of the sources of pollutants is fungus. Fungi are present almost everywhere in indoor and outdoor environments. Building materials supporting fungal growth must be remediated as rapidly as possible in order to ensure a healthy environment. The goal of this study is to compare the growth of indoor fungal by using three different antifungals such as potassium sorbate, zinc salicylate and calcium benzoate. The indoor fungi were isolated from selected room at Faculty of Civil and Environmental Engineering (FKAAS). The objective is to enumerate the growth of indoor fungal after incorporate with antifungal at different types of wall finishes and evaluate its efficiency. This research was done on three main substrates which are wood, plasterboard and concrete. These main materials were each coated with four types of coating which are thin wallpaper, thick wallpaper, glycerol based paint and acrylic paint. The growth rate was monitored as all the materials was applied with the antifungal. The antifungal has reduced the growth rate of the fungus but depending on the type of material and coating that is used. Results shows that for wood substrate, the best antifungal treatment is a mix of thick wallpaper and calcium benzoate, where the growth stops at 53% (CB 53% < PS 87% < ZS 90% < CTRL 93%). As for plasterboard substrate, thin wallpaper and potassium sorbate hinders the growth at 40% (PS 40% < ZS 73% < CB 80% < CTRL 97%) whereas for concrete substrate, acrylic paint and glycerol based paint incorporated with calcium benzoate renders the growth of fungi to stop at 0% throughout the test (Acrylic Paint = CB 0% < ZS 7% < PS 7% < CTRL 33%) and (Glycerol Based Paint = CB 0% < PS 70% < ZS 73% < CTRL 87%). Thus, the best building material would be concrete with the application of calcium benzoate for paint type of wall finishing’s

Assessment of the sensitivity of current standard procedures for the isolation of Yersinia enterocolitica from pork mince : a dissertation presented in partial fulfilment (25%) of the requirements for the degree of Master of Veterinary Studies in Veterinary Public Health at Massey University

Y. enterocolitica and related species have been isolated from many types of food. The majority of isolates differ in biochemical and serological characteristics from typical pathogenic strains and are termed non-pathogenic or environmental strains. Usually the number of Y. enterocolitica organisms present in food products is low compared with the dominant background flora. The ability of current enrichment procedures to recover pathogenic strains of Y. enterocolitica from different foods is often inadequate probably because different strains require different conditions for optimum growth (De Boer 1992). An efficient enrichment procedure should confer some selective advantage to the desired type of microorganism by promoting its growth relative to the competing microflora. At present, there is no single ideal isolation procedure available for the recovery of pathogenic strains of Y. enterocolitica from foods. The aim of this study was to determine the recovery rate of Y. enterocolitica biotype 4/serotype 0:3 from samples of pork mince inoculated with known numbers of the microorganism using different enrichment parameters (Time, temperature and pH) and Cefsulodin-Irgasan-Novobiocin (CIN) agar as the selective medium. The experiment was conducted in two trials using different bacterial dilutions. Three pork mince samples in duplicate were inoculated with known quantities of Y. enterocolitica biotype 4/serotype 0:3 organisms and subjected to cold enrichment in phosphate buffered saline (PBS) with a pH of 7.6, 6.6 and 5.5 at 25°C for 2 days, 10°C for 7 days and 4°C for 21 days. CIN agar was used as the selective medium. Pre-inoculation control samples were selected and plated in CIN on day O and on day 21 after PBS enrichment at 4°C. In Trial one Y. enterocolitica organisms were recovered from all 3 samples incubated at 25°C for 2 days and from 1 out of 3 inoculated samples incubated at 4°C for 21 days. There were no organisms recovered from other inoculated samples. The control sample did not show any environmental contamination with Yersinia species. In Trial two, Y. enterocolitica was recovered from 1 out of 3 duplicate samples enriched in PBS with pH 6.6 and incubated at 25°C for two days. Y. enterocolitica was not recovered from other inoculated samples. Y. intermedia was isolated from all pH, temperature and time combinations and also from control samples. The following conclusions can be drawn from this experiment. Incubation at high temperature (25°C) and short duration (48 hours) can be used as an efficient method for isolating Y. enterocolitica from pork samples. The standard incubation period of 21 days required for cold enrichment at 4°C is too long for the isolation of pathogenic strains, because of possible growth of environmental microorganisms. A pH of 6.6 is less efficient than 7.6 for enrichment although occasional isolation can be made using this pH. Enrichment in PBS with a pH of 5.5 with any time as well as temperature combinations and incubation at 10°C for 7 days are not ideal for isolation of pathogenic Yersinia enterocolitica strains. Of the three enrichments (PBS 7.6, 6.6, 5.5) used in this experiment, PBS with pH 7.6 was found to be most efficient to others

Colonial Legacies, Postcolonial Biologies: Gender and the Promises of Biotechnology

Three decades of work in the feminist studies of science and technology have shaped our evolving understandings of the relationships between sex, gender, and biotechnology. Sex, and gender are most often reduced to binary categories, severely limiting our conceptions not only of human diversity, but those of science and technology. Using two case study set in India, transnational surrogacy and the Indian Genome Variation Project, this paper explores how popular positions around biotechnology are reduced to binary positions promoting and opposing biotechnology as the solution for the economic and social development of India. By locating surrogacy and genomics within the larger geopolitical, historical, economic and cultural transformations of postcolonial India, the paper argues that both technologies are far more complex in their impact on women and gender. Why does technology become the major site of hope for the future? Why does genomics become the site for the promises of good health? Why has India become a site for reproductive tourism, and transnational surrogacy in particular? Drawing on the social studies of science, the paper argues that technology and human bodies are never neutral but always prefigured with a gender, race, caste and sexuality. Surrogacy and genomics should be understood within these colonial and postcolonial histories of science and technology

The Aliens in Our Midst: Managing Our Ecosystems

"The Aliens in Our Midst: Managing Our Ecosystems," in Controversies in Science and Technology : From Sustainability to Surveillance, edited by Daniel Lee Kleinman, et al., Oxford University Press, Incorporated, 2014. 228-24

Cluster formation versus star formation rates around six regions in the LMC

The stellar population and star clusters around six regions in the Large Magellanic Cloud (LMC) are studied to understand the correlation between star formation and cluster formation rates. We used the stellar database of the OGLE II LMC survey and the star cluster catalogues. The observed distribution of stellar density on the colour-magnitude diagrams (CMDs) were compared with the synthetic ones generated from the stellar evolutionary models. By minimising the reduced chi-square values, the star formation history of the regions were obtained in terms of the star formation rates (SFRs). All the regions were found to show large SFRs between the ages 500 Myr - 2 Gyr with lower values for younger and older ages. The correlated peak in the cluster and SFRs is found for ages $sim$ 1 Gyr, and for ages less than 100 Myr. Five out of six regions show significant cluster formation in the 100 - 300 Myr, while the SFRs were found to be very low. This indicates anti-correlation between star and cluster formation rates for the 100 - 300 Myr age range. A possible reason may be that the stars are predominantly formed in clusters, whether bound or unbound, as a result of star formation during the above age range. The enhanced cluster formation rate at 100 - 300 Myr age range could be correlated with the encounter of LMC with the Small Magellanic Cloud, while the enhanced star and cluster formation at $\sim$ 1 Gyr does not correspond to any interaction. This could indicate that the star formation induced by interaction is biased towards group or cluster formation of stars.Comment: to appear in A&A, 12 pages including 7 figure

Distributed intelligent robotics : research & development in fault-tolerant control and size/position identification : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Computer Systems Engineering at Massey University

This thesis presents research conducted on aspects of intelligent robotic systems. In the past two decades, robotics has become one of the most rapidly expanding and developing fields of science. Robotics can be considered as the science of using artificial intelligence in the physical world. Many areas of study exist in robotics. Among these, two fields that are of paramount importance in real world applications are fault tolerance, and sensory systems. Fault tolerance is necessary since a robot in the real world could encounter internal faults, and may also have to continue functioning under adverse conditions. Sensory mechanisms are essential since a robot will possess little intelligence if it does not have methods of acquiring information about its environment. Both these fields are researched in this thesis. In particular, emphasis is placed on distributed intelligent autonomous systems. Experiments and simulations have been conducted to investigate design for fault tolerance. A suitable platform was also chosen for an implementation of a visual system, as an example of a working sensory mechanism

Structure of the Large Magellanic Cloud from the Near Infrared magnitudes of Red Clump stars

The structural parameters, like the inclination, i and the position angle of the line of nodes (PA_lon) of the disk of the Large Magellanic Cloud (LMC) are estimated using the JH photometric data of red clump stars from the Infrared Survey Facility - Magellanic Cloud Point Source Catalog (IRSF-MCPSC). The observed LMC region is divided into several sub-regions and stars in each region are cross identified with the optically identified red clump stars to obtain the near infrared magnitudes. The peak values of H magnitude and (J-H) colour of the observed red clump distribution are obtained by fitting a profile to the distributions and also by taking the average value of magnitude and colour of the red clump stars in the bin with largest number. Then the dereddened peak H0 magnitude of the red clump stars in each sub-region is obtained. The RA, Dec and relative distance from the center of each sub-region are converted into x, y & z Cartesian coordinates. A weighted least square plane fitting method is applied to this x,y,z data to estimate the structural parameters of the LMC disk. A reddening map based on (J-H) colour of the RC stars is presented. When the peaks of the red clump distribution were identified by averaging, an inclination of 25.7 +/- 1.6 and PA_lon = 141.5 +/- 4.5 were obtained. We estimate a distance modulus of 18.47 +/- 0.1 mag to the LMC. Extra-planar features which are in front as well as behind the fitted plane are identified which match with the optically identified extra-planar features. The bar of the LMC is found to be part of the disk within 500 pc. The estimates of the structural parameters are found to be independent of the photometric bands used for the analysis. We find that the inner disk, within 3.0, is less inclined and has larger value of PA_lon when compared to the outer disk.Comment: 13 pages, 16 figures, Accepted for publication in the journal Astronomy & Astrophysic

RR Lyrae stars in the inner LMC: Where did they form?

RR Lyrae stars (RRLS) belong to population II and are generally used as a tracer of the host galaxy halo. The surface as well as vertical distribution of RRLS in the inner Large Magellanic Cloud (LMC) are studied to understand whether these stars are actually formed in the halo. RRLS identified by the OGLE III survey are used to estimate their number density distribution. The scale-height of their distribution is estimated using extinction corrected average magnitudes of ab type stars. The density distribution mimics the bar, confirming results in the literature. The distribution of their scale height indicates that there may be two populations, one with smaller scale-height, very similar to the red clump stars and the other, much larger. The distribution of the reddening-corrected magnitude along the minor axis shows variation, suggesting an inclination. The inclination is estimated to be i = 31.3 (3.5) degrees, very similar to the inclination of the disk. Thus, the RRLS in the inner LMC mimic the bar and inclination of the disk, suggesting that a major fraction of RRLS is formed in the disk of the LMC. The results indicate that the RRLS in the inner LMC trace the disk and probably the inner halo. They do not trace the extended metal-poor halo of the LMC. We suggest that a major star formation event happened in the LMC at 10-12 Gyrs ago, resulting in the formation of most of the inner RRLS, as well as probably the globular clusters, inner halo and the disk of the LMC.Comment: A&A Letters (in press