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Articles 421 - 450 of 469

Full-Text Articles in Life Sciences

Pruning And Nutrition Of Outdoor Cut Foliage Crops, Andy Whelton Jan 2000

Pruning And Nutrition Of Outdoor Cut Foliage Crops, Andy Whelton

Theses

The rapidly expanding cut foliage industry in the South of Ireland aims to satisfy the demands of an exacting market requiring well furnished quality stems for use in the manufacture of foliage and flower bouquets. The studies examined, in detail, aspects of pruning and nutrition of genera currently important to this evolving industry. Recommendations for the optimum time of pruning Eucalyptus pulverulenta and Pittosporum tenujolium are given. Pruning regimes for Eucalyptus parv,folia and E. glaucescens, Pittosporum tenufolium, Ozothamnus rosmarinfolius ‘Silver Jubilee’ and Rhododendron ponticum were examined and guidelines on best practices are outlined. A nutrition experiment to examine the effect …


The Molecular Characterisation Of Selected Epidemic Associated Gram Negative Pathogens In Southern Ireland, Mairéad Daly Jan 2000

The Molecular Characterisation Of Selected Epidemic Associated Gram Negative Pathogens In Southern Ireland, Mairéad Daly

Theses

This study was undertaken to evaluate various molecular techniques for the analysis of Gram negative bacterial associated epidemics. The first investigation dealt with bovine mastitis outbreaks, where the causative agent was identified as Pseudomonas aeruginosa. Epidemiological findings, suggested that all herds were infected from teat wipes that were contaminated with this organism. Initial investigations using the polymerase chain reaction (PCR), indicated a possible clonal relationship between all outbreak linked strains, with one exception. This finding was confirmed following pulsed-field gel electrophoresis (PFGE) and ribotype analysis. PCR was again employed to study a rather unusual epidemic, involving Salmonella tel-el-kebir over a …


The Molecular Epidemiology Of Rotavirus In Ireland, Fiona O'Halloran Jan 2000

The Molecular Epidemiology Of Rotavirus In Ireland, Fiona O'Halloran

Theses

Between 1997 and 1998, 3,136 cases of rotavirus diarrhoea were detected in Irish children less than 2 years of age. Hospital inpatients accounted for 80% of these infections, with the remainder being diagnosed in general practice. A large percentage of infections were detected in neonates, suggesting a possible inadequate maternal derived protection from existing indigenous strains. This feature suggested the possible existence of ‘novel’ strains circulating in Ireland. No data describing the epidemiology of rotavirus strains in this country currently exists. Furthermore no assessment of the potential health-economic impact or quantitation of potential disease burden was ever undertaken

Three hundred …


The Atomic Force Microscope In The Elucidation Of Leukocyte Abnormality, Derbrenn O'Connor Jan 1999

The Atomic Force Microscope In The Elucidation Of Leukocyte Abnormality, Derbrenn O'Connor

Theses

The aim of this project was to investigate the novel use of the atomic force microscope (AFM) as a technique in the elucidation of leukocyte abnormality. To this end, comparative AFM imaging and elasticity studies were performed on normal and myeloid leukaemic leukocytes.

Initially, an evaluation of techniques for the isolation of specific leukocyte (e.g. lymphocytes, granulocytes, etc.) populations from whole blood or leukocyte concentrates, was carried out. It was found that a silanised glass surface failed to select and immobilise a leukocyte population. However, centrifugation of whole blood in an Isopaque-ficoll gradient solution yielded a viable mixed leukocyte population …


New Polyether Toxins From Shellfish And Marine Phytoplankton: Isolation Studies And Development Of Analytical Methods, Alan G. Bishop Jan 1999

New Polyether Toxins From Shellfish And Marine Phytoplankton: Isolation Studies And Development Of Analytical Methods, Alan G. Bishop

Theses

There are three classes of polyether toxins responsible for Diarrhetic Shellfish Poisoning (DSP) world-wide. The causative toxins are okadaic acid (OA) and derivatives (DTXs), pectenotoxins (PTXs) and yessotoxins (YTXs). The origin of these toxins are phytoplankton from Dinophysis or Prorocentrum spp. OA has been demonstrated for most outbreaks in Europe and more recently a new isomer DTX-2 has been reported in Ireland.

Marine phytoplankton biomass samples consisting predominantly of Dinophysis acuta, were acquired using a large double plankton net from waters off the South-west coast of Ireland. Analysis of unialgal samples using high performance liquid chromatography (HPLC) with fluorescence and …


Extraction And Characterisation Of Essential Oils From Waste Eucalyptus Foliage, Hugh O'Reilly Jan 1999

Extraction And Characterisation Of Essential Oils From Waste Eucalyptus Foliage, Hugh O'Reilly

Theses

Extraction procedures such as steam distillation, solvent and soxhlet extraction have been investigated to determine the most effective method of extracting essential oil from the foliage of a number of species of Eucalyptus cultivated in Co. Kerry. Steam distillation has been found to be the most effective method of extraction. The steam distillation extraction method has been thoroughly studied in order to determine the factors affecting yield and composition of the distillate. Alteration of the distillation time has been found to produce oil high in 1,8-cineole content, a requirement of medicinal quality oil. The choice of individual distillation still used …


Methicillin Resistant Staphylococcus Aureus (Mrsa): Molecular Detection And Dna Fingerprinting, Leslie Cotter Jan 1998

Methicillin Resistant Staphylococcus Aureus (Mrsa): Molecular Detection And Dna Fingerprinting, Leslie Cotter

Theses

Throughout the 1990s, the incidence of methicillin-resistant Staphylococcus aureus has increased in many health care areas including acute and chronic care facilities, outpatient clinics and in the community. Once introduced into a health care environment, this nosocomial pathogen can spread rapidly and as MRSA are resistant to multiple antibiotics, treatment is often difficult. Therefore effective infection control measures are required to prevent cross-infection and further spread of endemic strains.

In this study, a sensitive and specific triplex-PCR assay was designed for MRSA detection, wherein three genes, the methicillin resistance gene (mecA). femA and the extracellular thermonuclease gene (rmc) were simultaneously …


Development Of An Atomic Force Microscopic Immunosensor For The Ferritin Antigen, Brendan O'Connell Jan 1998

Development Of An Atomic Force Microscopic Immunosensor For The Ferritin Antigen, Brendan O'Connell

Theses

The adsorption conditions for a range of different immunoreactants to both polystyrene and ultrasmooth silanised silicon surfaces are optimised. The conditions studied were concentration of protein, time and temperature of incubation, pH, molarity and ionic strength of the buffer. The anti-ferritin surface was selected as our model system. This immunosensor was used to develop and evaluate a millispot ELISA for ferritin. The millispot ferritin ELISA developed utilises a sample volume of 6pl and a sample incubation time of 10 minutes. Precision and accuracy studies show the assay to have a dynamic assay range of 7.8-lOOng/ml ferritin. The millispot ELISA detected …


Evaluation Of The Role Of Fructosamine As An Indicator Of Diabetic Control, Katherine Hooley Jan 1998

Evaluation Of The Role Of Fructosamine As An Indicator Of Diabetic Control, Katherine Hooley

Theses

Diabetes mellitus, a common metabolic disease, is characterised by excess circulating glucose concentrations. Such a hyperglycaemic status provides the stimulus for irreversible glycation (non-enzymatically post-translational) of structural and functional proteins. Protein glycation, although a cause of complication (neuropathy, micro/macrovascular disease), provides a time-averaged index of diabetes status and control. In particular, glycated plasma proteins analysis, i.e., the fructosamine assay, has received favourable response due to its speed, simplicity, low cost, and ease of automation. However, lack of standardisation and a universally-accepted calibrant has limited technical and subsequent clinical confidence in fructosamine analysis. In response, a comprehensive technical evaluation (including novel …


Development Of A Differential Assay To Selectively Measure Α-Amylase Isoenzymes., Miriam O'Connor Jan 1998

Development Of A Differential Assay To Selectively Measure Α-Amylase Isoenzymes., Miriam O'Connor

Theses

α-Amylase is a heterogeneous polypeptide, primarily found in the Salivary and Pancreatic glands, giving rise to two isoenzymes, namely Salivary- and Pancreatic-type Amylases. Total α-Amylase activity measurements are routinely carried out in hospital laboratories to aid in the diagnosis of diseases of the pancreas and in the investigation of pancreatic function in patients with severe abdominal pains. With the development and wide availability of modem chromogenic oligosaccharide substrates specific for Amylase, assays have become more sensitive, rapid and easier to use.

Differential Amylase Isoenzyme assays ware developed to distinguish isoenzyme levels. Several methods were developed for isoenzyme determination. Of these. …


Development And Validation Of An Improved Ultrasensitive Assay For Cardiac Troponin I (Ctni), William G. Blake Jan 1998

Development And Validation Of An Improved Ultrasensitive Assay For Cardiac Troponin I (Ctni), William G. Blake

Theses

Cardiac troponin I (cTnl) has been reported to be a highly specific marker for myocardial injury. In patients suffering from acute coronary syndromes, a sensitive serum marker which is closely related to the extent of myocardial damage which provides prognostic data and which can be measured rapidly is desirable. In this thesis a “sandwich” enzyme immunoassay was developed to measure cTnI. The developed assay was reproducible with the inter assay precision ranging from 4.8-14% and the intra assay precision ranging from 3.1-9.5%. The limit of detection of the assay was calculated as 0.385 ng/ml. The upper reference range (non-parametric 95% …


Development And Validation Of Flow-Injection (Continuous-Flow) Elisa Techniques., Declan Gerard Spillane Jan 1998

Development And Validation Of Flow-Injection (Continuous-Flow) Elisa Techniques., Declan Gerard Spillane

Theses

A flow-through enzyme-linked immunosorbent assay was developed based on affinity chromatography using the determination of ferritin in serum as a model system. In this method, samples and standards are introduced to separate columns containing immobilised anti-ferritin antibody, and antigen bound by solid-phase antibody is subsequently detected using an anti-ferritin-alkaline phosphatase conjugate. To detect immobilised label, p-nitrophenyl phosphate is added and product is developed in the column at room temperature. Following elution of product from the column, the absorbance is measured and the columns are regenerated using a low pH elution. The final developed system requires approximately 1.5 h for the …


Molecular Analysis Of The Factor V-Leiden Mutation In A Cardiac Transplant Patient Population, Caroline Maher Jan 1998

Molecular Analysis Of The Factor V-Leiden Mutation In A Cardiac Transplant Patient Population, Caroline Maher

Theses

Venous thrombosis is a serious health problem affecting 1 in 1000 individuals annually. Until recently the pathogenic factors underlying thrombosis were associated with genetic defects in protein C, protein S and antithrombin III. However these were recognised in fewer than 5-10% of thrombotic patients. A breakthrough was made with the discovery of activated protein C resistance (APCr) which is associated in 90% of cases v/herein a G-->A transition in the factor V gene results in an abnormal molecule, Factor V Leiden. APCr is a major risk factor for thrombosis being present in 20-60% of thrombotic patients. Recently a G-^A …


Development Of An Elisa Method For The Measurement Of Cd44 Expression In Human Serum, Ciara Hurley Jan 1998

Development Of An Elisa Method For The Measurement Of Cd44 Expression In Human Serum, Ciara Hurley

Theses

CD44 is a cell surface glycoprotein (mol. wt. =85-95 kDa) which has been implicated in lymphocyte-HEV interactions and the process of lymphocyte homing. CD44 is a complex glycoprotein which undergoes extensive alternative splicing to generate various CD44 isoforms. CD44 functions include the delivery of an activation signal to T-cells, binding to hyaluronate, mediation of lymphocyte homing, and the spread of metastatic cells. CD44 has been particularly implicated in the dissemination of non- Hodgkin's lymphoma and as such may serve as a useful prognostic marker of disease progression. CD44 measurement in serum may provide a rapid, inexpensive and relatively non-invasive prognostic …


The Measurement Of Angiotensin-Converting Enzyme In Human Serum, Andrew P. Kenny Jan 1997

The Measurement Of Angiotensin-Converting Enzyme In Human Serum, Andrew P. Kenny

Theses

The measurement of angiotensin converting enzyme using the substrate FAPGG was investigated with a view to optimising its performance. It was found that a 100 mnol/l triethanolamine-HCl buffer gave a significantly higher absorbance change then the existing TRIS-HCl in the method. As this buffer has not been previously described in the measurement of ACE it was decided to introduce this buffer into a kinetic procedure and evaluate the modified method. The reference interval for the triethanolamine Method was determined by measuring the ACE activity on 200 serum from blood donors and a significant difference (P < 0.05) in the SACE activity of male and female donors was observed.

The modified method was found …


Use Of Conductance Technology To Determine The Bioactivity Of Oxytetracycline-Hydrochloride, Michael Mc Donagh Jan 1996

Use Of Conductance Technology To Determine The Bioactivity Of Oxytetracycline-Hydrochloride, Michael Mc Donagh

Theses

The biological activity of oxytetracycline-hydrochloride was investigated using the indirect conductivity method which is based on the measurement of metabolically generated CO2. A number of laboratory strains and a fresh natural inoculum were exposed to oxytetracycline in the presence and absence of 12% sterile sediment. Results comparing sediment and sediment free systems for all test cultures revealed elevated minimum inhibitory concenrations (MIC) of the agent in the presence of sediment; percentage bioactivity results ranged between 0.50 and 2.07%. pH differences betw'een sediment and sediment-free systems were found not to effect MIC results, and the use of different buffers resulted in …


Acidic Marine Biotoxins Implicated In Diarrhetic Shellfish Poisoning, Eoin P. Carmody Jan 1996

Acidic Marine Biotoxins Implicated In Diarrhetic Shellfish Poisoning, Eoin P. Carmody

Theses

An okadaic acid (OA) etiology has been demonstrated for most outbreaks of diarrhetic shellfish poisoning (DSP) in Europe, An isomer of OA, dinophysistoxin-2 (DTX-2), has recently been found in Irish waters and, in 1991 and 1994, was the major toxin during prolonged infestations in cultivated mussels (Mytilus edulis) along the south-west coast of Ireland.

The OA class of DSP toxins have been analysed by HPLC using modified versions of three established fluorescent derivatisation methods. A ‘dual tag’ method for the confirmation of specific toxins has also been developed.

Survey work has been carried out over the past four years on …


Development Of A New Hydroseeding Process For Soil Stabilisation And Vegetation, Eileen T. Keane Jan 1996

Development Of A New Hydroseeding Process For Soil Stabilisation And Vegetation, Eileen T. Keane

Theses

A variety of mechanical and chemical extraction procedures were used to produce crude alginate gels from 3 seaweed species. These viscous hydrocolloidal substances had excellent adhesive properties but did however prove phytotoxic to germinating seeds. Experimental gels were subsequently refined and germination trials were carried out to determine optimum gel types. Pilot field trials were set up to compare the 2 most favourable gels with existing commercial hydroseeding products imported from Norway and Sweden. These tests involved the use of experimental plots on loam and sand substrates with slopes of 0^, 22^ and 45^. A number of biodegradable organic substances …


Availability And Use Of Food Resources By Two Species Of Automolus (Aves, Furnariidae), Grace Patricia Servat-Valenzuela Jan 1995

Availability And Use Of Food Resources By Two Species Of Automolus (Aves, Furnariidae), Grace Patricia Servat-Valenzuela

Theses

Foraging specialization is one mechanism that has been hypothesized to promote species coexistence and, thus, higher bird species diversity in tropical forests. Dead-leaves suspended in vegetation above the forest floor constitute a focal substrate that may promote specialization (Rosenberg 1990a, b). In a study locality in Amazonia, Remsen and Parker (1984) reported 16 species of birds closely associated with this system. Therefore, it represents a microcosm of high diversity in tropical forests. As such, one natural question is how this substrate can support so many coexisting species, and at what level does specialization occur? In the present study, I address …


The Surveillance And Control Of Foodborne Diseases, Donal J. Daly Jan 1995

The Surveillance And Control Of Foodborne Diseases, Donal J. Daly

Theses

There is great variation in the extent of surveillance of foodbome disease throughout the world. Some countries contribute important epidemiological and microbiological data to the WHO Surveillance Programme for Foodbome Diseases in Europe. While the UK is a major contributor to this programme, data from Eire has been non-existent. Trends in the incidence of foodbome disease in the UK may have particular relevance to Eire given the similarity of culture. Microbiological and epidemiological data in relation to foodbome pathogens, foods most frequently incriminated in outbreaks, places where outbreaks occur, together witli the main contributory factors are discussed. The broader area …


Effect Of Lead On Flexor Muscle Contraction And Photochemically-Induced Platelet Aggregation In Pial Microcirculation Of The Mouse, Amna Hamad Al Dhaheri Dec 1994

Effect Of Lead On Flexor Muscle Contraction And Photochemically-Induced Platelet Aggregation In Pial Microcirculation Of The Mouse, Amna Hamad Al Dhaheri

Theses

Lead is one of many heavy metal ions that can effectively compete for the binding sites of calcium, block the calcium channels and disturb the ion exchange. As a result, lead would be expected to affect the calcium-mediated cell functions. Muscle contraction and platelet aggregation are two important functions in which Ca2+ plays a major role and ultimately are affected by lead. Experiments were carried out to investigate the effect of lead on mouse flexor muscle contraction and on photochemically-induced platelet aggregation in pial microcirculation. A study of an acute exposure (1, 5, 10 and 25 µM) and a …


Breeding Biology Of The Black Storm-Petrel At Islas Los Coronados, Baja California, Mexico, William T. Everett Jan 1991

Breeding Biology Of The Black Storm-Petrel At Islas Los Coronados, Baja California, Mexico, William T. Everett

Theses

Twenty-nine visits to Middle Rock, Islas Los Coranados, were made between March 1989 and September 1990, including 10 overnight visits. Breeding phenology was studied, including timing of colony attendance by adult birds, timing of egg laying, hatching, and fledging. Over 200 birds were banded to determine nest site tenacity and pair bond retention. Details were recorded on nest site selection, interspecific competition, breeding success, chick growth and plumage development, adult morphometrics, molt, food items, vocalizations, and ectoparasites.


Stabilization/Solidification Of Organic Containing Wastes Using Organophilic Clay And Coal Fly Ash, Edith Lagoutte Dec 1990

Stabilization/Solidification Of Organic Containing Wastes Using Organophilic Clay And Coal Fly Ash, Edith Lagoutte

Theses

The relative merits of eight different coal fly ashes for use in the stabilization/Solidification of a waste containing both heavy metals and pentachlorophenol were investigated. Also studied, was the possible use of either untreated or treated (with hexade-cyl ammonium bromide) clay to enhance the stabilization of the organic. The sample composition was : 62% foundry baghouse dust (or 60% if 2% clay as added to the sample), 4.5% cement, 14% coal fly ash, 19.5% water. Pentachlorophenol was chosen as represen¬tative of the organic contamination. All tests were performed after curing the samples at 22°C, 98% Rh for 28 days. The …


Quantitative Determination Of Formaldehyde In Ambient Air, Wen-Shao Chou Jan 1990

Quantitative Determination Of Formaldehyde In Ambient Air, Wen-Shao Chou

Theses

Formaldehyde has been shown in the laboratory to play a critical role in the chemistry of polluted air. The method which we discuss in this paper was evaluated under practical field conditions in the Northern New Jersey Staten Island Urban Air Toxics Project. Formaldehyde in ambient air is concentrated and derived by passing a known quantity of air through a silica column impregnated with 2,4-dinitrophenylhydrazine (DNPH). The silica is eluted with acetonitrile and the concentration of formaldehyde is determined by High Performance Liquid Chromatograph (HPLC) with UV detection. A description of procedural details for coating silica cartridges with 2,4-DNPH acidified …


Benzo(A)Pyrene Ingested From Composite Meals : Analysis And Method Development Related To Total Human Exposure, Che-Han Hsu Jan 1990

Benzo(A)Pyrene Ingested From Composite Meals : Analysis And Method Development Related To Total Human Exposure, Che-Han Hsu

Theses

Polycyclic aromatic hydrocarbons including benzo[a]pyrene (BaP) have been known for many years to be environmental carcinogen. Moreover, B(a)P has often been used as an indi¬cator for the carcinogenic potency of environmental matter. One of its exposure pathways, ingestion, may possibly be more important than other routes, conventionally studied such as inhalation. The purposes of this thesis are 1) to analyze the B(a)P concentrations in weekly composite and some daily meals obtained in the Total Human Exposure to Environmental Substances (THEES) study, 2) to develop techniques which can measure the levels of B(a)P in foods accurately and effici¬ently, 3) to compare …


Degradation Of Refractory Organic Pollutants In Tar, Water And Soil Matrices By Ozone Or Hydrogen Peroxide With Ultraviolet Light, Liang-Jiun Uang Jan 1990

Degradation Of Refractory Organic Pollutants In Tar, Water And Soil Matrices By Ozone Or Hydrogen Peroxide With Ultraviolet Light, Liang-Jiun Uang

Theses

The objective of this research is to develop a method to degrade refractory Tar materials, higher molecular weight 3-5 ring Poly Aromatic Hydrocarbons (PAH's) or degrading these highly refractory PAH structures so that they are amenable to further treatment by biological or chemical methods. The process utilized to achieve this is to treat contaminated soils or tar materials with hydrogen peroxide or ozone plus ultraviolet light. Analysis of 27 specific PAH's was done by gas chromatograph (Flame Ionization Detection) for the reactants and products. The contaminated soil showed significantly lower levels of these PAH's after treatment.


Microbial Competition In The Biodegradation Of Phenol, Mary Ellen Frank May 1989

Microbial Competition In The Biodegradation Of Phenol, Mary Ellen Frank

Theses

Three phenol degraders were isolated from the mixed liquor of the Livingston, NJ municipal treatment plant. Shaker flask experiments using one of the degraders (a Pseudomonas sp.) resulted in the determination of its kinetic rate constants. The second phenol degrader (a Xanthamonas) lost its phenol degrading ability while being stored, and its kinetic rate constants could not be determined. The third phenol degrader (a Pseudomonas cepacia) formed flocs which interfered with the spectrophotometric determination of biomass and therefore its kinetic rate constants also could not be determined.

Mixed culture experiments were carried out using a the Pseudomonas sp. and a …


Thermal Desorption Of Hazardous And Toxic Organic Compounds, Manuel S. Nolau May 1989

Thermal Desorption Of Hazardous And Toxic Organic Compounds, Manuel S. Nolau

Theses

The purpose of this thesis is to study the thermal desorption behavior of toxic organic compounds, specifically o-xylene, p-xylene, ethyl benzene, p-chlorotoluene, and anthracene, from soil with respect to temperature and time, and to develop a mathematical model that will describe this desorption behavior. The model will allow prediction of the concentration of an organic contaminant in commercial soil desorption system over time given a known set of parameters of the specific chemical as well as flow rate and temperature. For this purpose, two sets of experiments were done: These are identified as 1. Thermal desorption and 2. plug flow …


Study Of An Analytical Method For Benzo(A)Pyrene Metabolites In Human Urine, Zheng Ouyang May 1989

Study Of An Analytical Method For Benzo(A)Pyrene Metabolites In Human Urine, Zheng Ouyang

Theses

A method developed by Becher and Bjorseth for analysis of PAH metabolites in urine was employed to investigate human exposure to benzo(a)pyrene (BaP) - an ubiquitous environmental carcinogen. Preliminary results are presented showing the relationship between exposure to BaP and urinary elimination. Although the correlation between the two variables is not statistically significant, there appears to be a positive association with selected exposure varibles such as smoking. The identification of an association may establish urinary BaP as a marker of exposure.

However, detailed study of the analytical procedure indicated that recoveries with this method were as low as 3-8% for …


Environmental Assessment In Bioethanol Technology Using Immobilized Yeast Cells, Minoo Kandy Zarnegar Jan 1989

Environmental Assessment In Bioethanol Technology Using Immobilized Yeast Cells, Minoo Kandy Zarnegar

Theses

This study is undertaken from the standpoint of water pollution evaluation in bioethanol technology, using immobilized yeast cells. Evaluation of water pollution caused by immobilized yeast fermentation is the main objective of this research.

The pollution in water remaining at the end of ethanol production, which is normally discharged in the wastewater stream, has been analyzed by the measurement of biological oxygen demand (BOD), since BOD measurement is one of the widely used parameters for water pollution evaluation. BOD obtained from produced water (stillage) was between the range of 115- 360 mg/l. The variation in BOD depended upon the removal …