34,236 research outputs found
Biocide treatment of biofilms
No full textBiofilms are ubiquitous in nature and microorganisms often exist as members of complex consortia, rather than as pure cultures. Their localised metabolic activity can create diffusion gradients of nutrients, fermentation byproducts and possible associated corrosion products within the biofilms; together with cell lysis, these cause a mosaic of microenvironments which may be totally different to the bathing phase. Such habitats pose a major, and often ignored, constraint on the interpretation of results obtained from laboratory disinfection models which can be physically, environmentally and physiologically inappropriate. For example, the most commonly used model for inactivation of microorganisms by biocides utilises the so-called 'Chick- Watson law': this implies that biocide concentration and contact time, the (C × T) factor, are the two key variables determining biocide efficacy. However, applications of the 'law' have assumed complete and uniform mixing of microorganisms and biocide, ignoring that diffusion might be rate limiting and that biocide concentration might decrease with time. Recent results suggest that many of the viable bacteria in chlorinated potable water are attached to surfaces and under these circumstances coliforms have withstood at least 12 ppm free residual chlorine. The use and efficacy of alternative biocides such as monochloramine against aquatic biofilms is discussed.</p
Comparison of selective agars for the isolation and identification of Klebsiella oxytoca and Escherichia coli from environmental drinking water samples
No full textVarious selective media were assessed for their ability to detect and differentiate Klebsiella oxytoca and Escherichia coli in environmental water samples. Only two, Membrane Lauryl Sulphate agar and Deoxycholate Agar, could differentiate the two coliforms from each other and from the ‘background’ heterotrophs in water and this was a consequence of E. coli's ability to grow at 44°C and 37°C whereas Kl. oxytoca could only grow at 37°C. Modified M‐FC medium effectively differentiated Kl. oxytoca but not E. coli in environmental samples. Other media characterized the different coliforms in pure culture but failed to do likewise in environmental samples. For example, pure cultures of E. coli fluoresced when MUG was added to the medium but single colonies on a mixed species plate failed to do so. MT7 agar distinguished the two coliforms from water heterotrophs but not from each other.</p
Control of Legionella pneumophila in a hospital water system by chlorine dioxide
No full textImmuno-compromised patients are particularly susceptible to Legionnaires' Disease. After three cases of the disease occurred in a hospital, a continuous dosing regime using chlorine dioxide was initiated to replace chlorination of the water system. This study identified a number of factors which may have resulted in conditions that would encourage the growth of the water-borne pathogen Legionella pneumophila. The residual chlorination was inadequate for microbial control at the taps furthest from the four storage tanks, of which two were found to be in excess for demand. The temperature of the water in the storage tanks was also found to be above 20° C; a temperature that would encourage microbial growth. A back-up calorifier was present and was found to contain L. pneumophila, and linseed oil-based sealants that provide nutrients for microbial growth were also prevalent as jointing compounds in the water circult. Although the shower heads were routinely disinfected, a requirement was identified to also disinfect the shower hoses. No L. pneumophila were recovered from the water system after the chlorine reduced dioxide disinfection trial. Biofilm was also dramatically reduced after disinfection; however, small microcolonies were identified and proved to be metabolically active when tested with a metabolic indicator. Using light and fluorescence microscopy, the pipe samples removed from the water system were rapidly analysed for biofouling, complementing existing microbiological methods.</p
Correspondence and Photograph from Ernest W. Wright to Dr. C. A. Bacote, August 30, 1977
No full textCorrespondence between Ernest W. Wright (Employment Security Agency, Georgia Department of Labor) and Dr. C. A. Bacote, 30 August 1977. Enclosed 8"x10" photograph circa 1955, depicting voter registration participants. Written on Verso: "Left to Right: (Seated): Dr. Clarence A. Bacote, Dr. William Hale, Mr. Ron Harris? Dr. Robert Brisbane (Standing): Mr. Michael? Mr. C. A. Scott? Mr. Milton White"
Faust : Romance Of The Secret Tribunals / By George W. M. Reynolds, Author Of "The Mysteries Of London", "Pickwick Abroad", &c. Illustrated In The First Style Of The Art
No full textFAUST : ROMANCE OF THE SECRET TRIBUNALS / BY GEORGE W. M. REYNOLDS, AUTHOR OF "THE MYSTERIES OF LONDON", "PICKWICK ABROAD", &C. ILLUSTRATED IN THE FIRST STYLE OF THE ART
Faust : Romance Of The Secret Tribunals / By George W. M. Reynolds, Author Of "The Mysteries Of London", "Pickwick Abroad", &c. Illustrated In The First Style Of The Art (1)
Cover (1)
Umschlagtitel (8)
Titelseite (9)
Contents (10)
Illustrations / Prologue (11)
Prologue (12)
Chapter I.-XCV. (14)
Epilogue (119
Letter from C. W. Pence, Colonel, 442nd Infantry Regiment, Commanding, Headquarters, 442nd Combat Team, to Kiku Saito, May 20, 1943
No full textA letter from C. W. Pence, Colonel, 442nd Infantry Regiment to Kiku Saito incarcerated in the Granada camp, Colorado. It informs her of her son, Minoru Frank Saito's arrival at Camp Shelby, Mississippi. It congratulates her for his enlistment and quoted the President Roosevelt's statement, "Americanism is not, and never was, a matter of race or ancestry. A good American is one who is loyal to this country and to our creed of liberty and democracy.
Correspondence, C. W. Tayleure to John Brown, Jr., June 18, 1879
No full textA letter to C. W. Tayleure to John Brown, Jr. concerning the death of Brown's brother, Watson. 5 pages
Aspects of MusicaLity in the industrial regions of Lancashire and Yorkshire between 1835 and 1914 with reference to its educational, sociological and religious basis
No full textThis study examines the musical life of Lancashire and Yorkshire people during the Industrial Revolution and shows how music became involved in current social, educational and religious changes. Changes also took place in music making itself, and these are observed through two contrasted case studies which show the transition from singing which took place informally in the semi-rural communities, where the singers used to meet in each others homes and perform in local churches, to the formal and institutionalised Choral Societies of the prosperous industrial towns. Popular song underwent a similar transition as the songs of the ballad singer gave way to those of the Music Hall. The evolution of public concerts further reflects the effects upon music of the changes in class and social structure which came with industrialisation and urbanisation. Attitudes changed too, and aspects of the Victorian ethos such as competition and self-help as a means of 'getting on' were accommodated into music’s wide-ranging rationale. These elements were evident in the brass band movement as well as in Competitive Festivals. Music was capable of such a varied role in society that it became to some extent 'All things to all men' - a cause worthy to be championed by educationalists and social reformers alike. Music therefore became an important ingredient in the developing state system of education, its most notable feature being the development of a systematic method of sight singing - Tonic Solfa. The Church had long been a pioneer in education and a significant aspect of this related to the training of musicians to provide music for the Services. This interest continued and widened, and the musical, educational, sociological and religious links were even more strongly forged as increasing numbers of people became involved in religious choral music
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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