Once current nuclear reactor operation ceases in the U.K. there will be an estimated 99,000 tonnes of irradiated nuclear graphite waste which may account for up to 30% of any future UK geological ILW disposal facility [1]. In order to make informed decisions of how best to dispose of such large volumes of irradiated graphite (I-graphite) within the UK nuclear programme, it is necessary to understand the nature and migration of isotopes present within the graphite structure. I-graphite has a combination of short and long term isotopes such as 14C, 3H and 36Cl, how these behave prior to and during disposal is of great concern to scientific and regulatory bodies when evaluating present decommissioning options. Various proposed decontamination and immobilisation treatments within the EU Euroatom FP7 CARBOWASTE program have been explored [2, 3]. Experiments have been carried out on UK irradiated British Experimental Pile Zero and Magnox Wylfa graphite in order to remove isotopic content prior to long term storage and to assess the long term leachability of isotopes. Several leaching conditions have been developed to remove 3H and 14C from the irradiated graphite using oxidising and various acidic environments and show mobility of 3H and 14C. Leaching analysis obtained from this research and differences observed under varying leaching conditions will be discussed. Thermal analysis of the samples pre and post leaching has been performed to quantify and validate the 14C and 3H inventory. Finally the research objectives address differences in leachability in the graphite to that of structural and operational variation of the material. Techniques including X-ray Tomography, Scanning Electron Microscopy, Autoradiography and Raman spectroscopy have been examined and show a significant differences in microstructure, isotope distribution and location depending of irradiation history, temperature and graphite source. Ultimately the suitability of the developed chemical treatments will be discussed as whether chemical treatment is a viable option prior to irradiated graphite long term disposal.

Hydromagnesite, the most stable of the basic magnesium carbonates, can be obtained by mining or by synthesis. Existing synthetic procedures have certain drawbacks which include, undesirable environmental effluents or high pressure and/or temperature requirements. Due to the lack of information in the literature, the aim of this study was to develop a cost effective procedure for the synthesis of basic magnesium carbonate from Mg(OH)2, not hampered by the above mentioned drawbacks. Following an extensive investigation into various parameters that influenced the final product, a simple procedure, based on sparging CO2 through a slurry of magnesium hydroxide in water until the pH reached 7.5-8.5, was developed. The solid portion of the slurry is dried at 80 or 120°C to deliver an unidentified basic magnesium carbonate and hydromagnesite respectively. The products were characterised by XRD, TG-DTA, surface area determination, SEM and FT-IR. The rehydration characteristics of the products were also investigated. By combining the information obtained by each technique, valuable information could be obtained. The synthesised products were evaluated for flame retardant application, due to the demand of mineral flame retardants which could compete with Mg(OH)2 and AI(OH)3. Compared to the traditionally used halogenated flame retardants, the mineral flame retardants deliver non-toxic, non-corrosive decomposition products and contributes in suppressing the emission of smoke in a fire. Results indicated that the basic magnesium carbonates compared favourably to Mg(OH)2 and AI(OH)3 and presented several advantages in terms of flame retardant applications. Further tests will be necessary to accurately assess the flame retardant effect of the basic magnesium carbonates. The possibilities however seem promising. / Thesis (PhD (Chemistry))--University of Pretoria, 2006. / Chemistry / unrestricted

Whilst working on a Masters degree on alternative solvents and extractants for the sorghum prolamin protein, kafirin, the author serendipitously found an ethanol-free method of making kafirin microparticles in dilute organic acid. Further, on drying a suspension of kafirin microparticles in dilute organic acid, a clear, transparent film was found to be formed. Microparticles from zein, the maize prolamin protein, have shown potential for food and pharmaceutical applications. Kafirin is more hydrophobic and less digestible than zein so it was hypothesised that it may form microparticles with superior properties. However, the structural and functional characteristics of kafirin microparticles and films made from them needed to be known before any potential applications could be exploited. Kafirin microparticles were made by dissolution of kafirin in glacial acetic acid followed by precipitation on addition of water. They were characterized by Light microscopy (LM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) and were found to be mainly spherical, porous and between 1-10 ìm in diameter. The kafirin microparticles had very large internal surface area due to the presence of many smooth walled holes or vacuoles of variable sizes, probably caused by entrapment of air during microparticle formation. Increasing the final acetic acid concentration resulted in kafirin microparticles of increased size, with an increasing number of internal holes. At 40% acetic acid the spherical microparticle structures completely disappeared and were replaced by an open matrix which resembled an expanded foam. The kafirin microparticles were found to form very thin (<15 ìm) free standing films and coatings. A minimum concentration of organic acid (10.8 percent) is required to form a cohesive kafirin microparticle film relative to the concentration of protein (1 percent for acetic acid). Some functional properties, e.g. smooth film surface properties, low water vapour permeability (WVP) and low protein digestibility of these films are superior to those of similar conventionally cast kafirin films. With the aim of exploiting the porous nature of kafirin microparticles for encapsulation of nutrient additives, several factors were examined for their influence on retarding protein digestibility. Retardation of digestibility of kafirin microparticles would allow controlled release of the encapsulated agent in the stomach and gastrointestinal tract. The importance of disulphide cross-linking and sorghum condensed tannin protein interactions were confirmed as major causal factors of the poor protein digestibility of sorghum. Gamma-kafirin was found to bind the most condensed tannins compared to the a-and b- kafirins, probably due to its high proline content. As expected, the protein digestibility of kafirin-tannin complexes was much lower than unbound kafirins. This seems to slow the biodegradation of kafirin films made with bound tannins. The antioxidants, catechin and sorghum condensed tannins were encapsulated within kafirin microparticles and the antioxidant release profiles investigated under simulated gastric conditions. Over a period of four hours, catechin and condensed tannin encapsulated kafirin microparticles showed virtually no protein digestion but released approximately 70% and 50% respectively total antioxidant activity. The mechanism for the formation of kafirin microparticles and films formed from them seems to involve controlled aggregation of kafirin molecules. Models for the formation of both were proposed based on an analogy with protein body formation and the potential ability of -kafirin to undergo a structural inversion exposing either hydrophilic or hydrophobic ends depending on the prevailing conditions. Research into cross-linking by physical or chemical agents is needed before practical applications can be exploited. However, encapsulation of catechin and sorghum condensed tannins within kafirin microparticles seems to be an effective way to use the binding properties of polyphenols with protein to enhance potential health benefits by controlled release of antioxidant activity within the stomach and gastrointestinal tract. Copyright / Thesis (PhD)--University of Pretoria, 2009. / Food Science / unrestricted

Superconductivity and ferromagnetism are two antagonistic physical phenomena which their coexistence in a uniform material can be resolved only under extraordinary conditions. The reason for that is the phonon-mediated attraction energy between electrons which results in the formation of the so-called Cooper pairs, is usually smaller that the exchange (Zeeman) interaction between electrons which tend to align the electron spins. However, non-zero total momentum Cooper pairs can be accomplished even in the presence of an exchange field as surprisingly! predicted first by Fulde and Ferrel [1] and independently by Larkin and Ovchinikov [2] nearly 50 years ago. This coexistence has already been observed experimentally in both bulk samples [3, 4] and in thin films [5-7] which result from a different type of electron-pairing mechanism which electrons with spin pointing in the same direction team up to form Cooper pairs with one unit of spin, resulting in the so-called triplet superconductivity. Apart from this so-called ferromagnetsuperconductors which both superconducting and ferromagnetism order parameters are present in a uniform material, hybrid systems [8] are made form materials with different or even mutually exclusive properties. Therefore the overall property can be strongly affected by the interaction between constituent materials. The present work, concerns such a hybrid system where Nb, a superconducting metal having transition temperature below 9.5K, is placed in contact with a ferromagnetic metal, Gd with bulk Curie temperature of around 290 K in a form of a nanocomposite. The mutual immiscibility of these two elements gives us the opportunity to take advantage of both the superconduction and ferromagnetism properties of the constituents and further study the transport and magnetic behavior of the system and their effects on each other specially on the critical current of the superconductor which is expected to be modified by the proximity of the ferromagnetic metal.

Human adenoviruses (HAdV) are non-enveloped viruses with an icosahedral capsid and a linear double-stranded DNA genome. These viruses belong to the family Adenoviridae and genus Mastadenovirus. An important property of the HAdV is that it is non-enveloped making it highly resistant to detergents and harsh environmental conditions. This virus is grouped in seven species (A-G) with more than 88 genotypes. These seven species are associated with several diseases, such as, respiratory infections, keratoconjunctivitis, urinary infections, hepatitis and gastrointestinal infections. The HAdV is one of the etiological causes of acute gastroenteritis, mainly caused by HAdV-F40 and HAdV-F41. The virus can be transmitted via the faecal-oral route, inhalation of respiratory droplets and direct contact with contaminated environments. The virus is known to be ubiquitous in environments where human contamination is likely to occur such as wastewater treatment plants. These human contaminations could occur through contaminated secretion and excretions within aqueous environments. There is currently a limited amount of information on the HAdV in water Molecular characterisation of human adenoviruses from environmental environments, particularly in Tshwane, Gauteng. Therefore, the aim of the study was to investigate the presence and genotypes of human adenovirus in environmental samples namely raw sewage and treated effluent, using molecular methods. For genotypic characterisation, Sanger sequencing was used on amplicons from 12 HAdV positive samples and next generation sequencing were used on all the amplicons from HAdV positive samples. A total of 150 environmental samples (75 raw sewage and 75 effluent) were collected from two wastewater treatment plants in Tshwane over the study period of 18 months. These environmental samples comprised of 1 L raw sewage and 10 L treated effluent samples. The primary viral recovery for the 1 L raw sewage and 10 L treated effluent samples were performed using skimmed milk flocculation procedure and glass wool adsorption elution technique, respectively. For secondary viral recovery, both environmental samples were subjected to polyethylene glycol/sodium chloride precipitation. Manual extraction was used to extract the nucleic acids from the virus concentrate with mengovirus (MV) used as an extraction control. For the quantification of HAdV, standard curves prepared from known dilutions of HAdV and MV were used. Human adenovirus was detected in 140/150 (93%) of the environmental samples comprising of 69/75 (92%) being raw sewage and 71/75 (95%) being effluent samples. The HAdV concentrations detected in wastewater treatment plant 1 (WWTP 1) ranged from 1.38x105 gc/L to 4.50 x 109 gc/L for raw sewage and 5.08x103 gc/l to 4.30x108 gc/L for effluent. The HAdV concentrations detected in WWTP 2 ranged from 6.84x104 gc/L to 1.69x1012 gc/L for raw sewage and 5.27x103 gc/L to 1.16x108 gc/L for effluent. The HAdV hexon amplification success rate from the nucleic acids was 43/140 (31%). Eighteen HAdV genotypes were successfully characterised using Sanger sequencing. The HAdV-D was the most predominant species in both WWTPs, follow by HAdV-B and HAdV-F. The HAdV-A and HAdV-E species were the least identified. Next generation sequencing identified four times as many genotypes as Sanger sequencing (77 different genotypes). The HAdV-D (types 8, 9, 13, 17, 19, 20, 23, 24, 28, 29, 32, 33, 36, 42, 44, 47, 49, 51, 56, 60, 62, 64, 67 and 81) and HAdV-B (types 2, 3, 7, 11 and 66) were the most predominant species followed by HAdV-F (types 40 and 41), HAdV-A (types 12 and 76), HAdV-E ( type 4) and HAdV-C (type 1). Testing wastewater treatment plants is advantageous as it allows for the detection and identification of HAdV types circulating in the surrounding communities. Due to the large number of species identified using NGS, it is the superior typing method and should be used for future studies. These include strains causing symptomatic and asymptomatic infections. Human adenovirus was detected at comparable frequencies in raw sewage and treated effluent wastewater, with slightly higher detection in effluent samples. However, the viability of these viruses is unknown and should be investigated in further studies. The detection of viruses in wastewater treatment plants are a public health concern as the treated effluent is discharged into rivers, which may be used by communities for domestic and recreational purposes. / Dissertation (MSc (Medical Virology))--University of Pretoria, 2020. / NRF, PRF / Medical Virology / MSc (Medical Virology) / Restricted

Thesis (Ph. D. (Chemistry)) -- University of Limpopo, 2019 / This work presents the synthesis, characterisation and application of poly(vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP) membrane prepared using a phaseinversion method. PVDF-HFP was blended with either functionalised multi-walled carbon nanotubes (MWCNTs), poly-amidoamine (PAMAM) dendrimeric MWCNTs or silver (Ag) nanoparticles and their combinations. Nanocomposite blends such as MWCNTs/PVDF-HFP, PAMAM-MWCNTs/PVDF-HFP, Ag-MWCNTs/PVDF-HFP and Ag-PAMAM-MWCNTs/PVDF-HFP were synthesised successfully. A variety of PVDF-HFP composite membranes prepared were characterised by X-ray powder diffraction (XRD), fourier transform infrared (FTIR), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and contact angle. The fMWCNTs, Ag-MWCNTs, PAMAM-MWCNTs and Ag-PAMAMMWCNTs nanocomposites were further characterised by Transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). FTIR spectra of PAMAMMWCNTs confirmed the formation of functional groups such as COOH, NCO, NH2 and PAMAM dendrimer. XRD analysis demonstrated that the crystallite sizes of the silver nanoparticles were larger (8.4 nm) than those of Ag-MWCNTs (7.8 nm) and Ag-PAMAM/MWCNTs (6.4 nm) nanocomposites. These findings were further confirmed by TEM analysis which showed Ag nanoparticles, Ag-MWCNTs and Ag-PAMAM/MWCNTs having diameters of silver particles between 9 to 20 nm, 5 to 10 nm and 4 to 8 nm respectively. The reduced Ag particle sizes was due to the complexation of MWCNTs and PAMAMMWCNTs with Ag metal ions, which correlates with an enhanced surface area in the nanocomposite membranes, leading to good filtration and antibacterial properties. TGA studies demonstrated that the thermal stability of PVDF-HFP composite membrane was greatly enhanced by the addition of PAMAM-MWCNTs. However, the composite membranes consisting of both Ag nanoparticles and MWCNTs on PVDFHFP did not improve the structural stability of PVDF-HFP. All composite membranes have shown stability up to 400 oC. The contact angle, porosity, swellability and water content measurements of the composite membranes were improved showing enhanced hydrophilicity due to addition of MWCNTs, PAMAM-MWCNTs and/or Ag nanoparticles. The scanning electron microscopy (SEM) images have depicted the formation of microporous structure, with few MWCNTs on the surface strongly interacting with PVDF-HFP as demonstrated by TGA, XRD and FTIR data. SEM cross-sections of PVDF-HFP composite membranes showed a mixture of fingure-like microvoids with a membrane diameter of approximately 180 μm. The BET data showed an improved surface area, pore volume and pore sizes of PVDF-HFP composite membranes when blended with fMWCNTs and PAMAM. These membranes also showed high fouling resistance, good desalination and high Cd(II) ions rejections during permeability studies. E. coli filtration studies indicated that 2.5 wt.% Ag-MWCNTs/PVDF-HFP and 1.8 wt.% Ag-PAMAM-MWCNTs/PVDF-HFP composite membranes displayed good microbial load reduction (100%) and excellent antibacterial properties as evidenced by the bacterial growth on the edges of the membranes. The microbial, physicochemical and chemical analysis of surface water samples from Sekhukhune area showed that the water was contaminated with Enterobacteriaeceae, E. coli, total coliform with high turbidity and total suspended solids above the South African national standard (SANS 241) water guidelines. After filtration with 1.8 wt.% Ag-MWCNTs/PVDF-HFP composite membrane, turbidity was reduced to 4 Nephelometric turbidity units (NTU), total suspended solids to 1 mg/L while Enterobacteriaeceae, E. coli and total coliform were undetectable and complied with SANS 241 limits. Chromium concentration levels were reduced from 0.194 to 0.0138 mg/L, after filtration with 1.8 wt.% Ag-PAMAM-MWCNTs/PVDF-HFP composite membrane also within acceptable SANS 241 limits. Adsorption studies of all composite membranes demonstrated that the adsorption processes of Cd(II) ions was well conformed to Freundlich model (R2 = 0.999), which suggests that the sorption process met heterogeneous adsorption. However, for Cr(VI) ions studies, the adsorption process was conformed to both Langmuir (R2 = 0.999) and Freundlich (R2 = 0.998) model which suggest that that the adsorption process meet both monolayer and heterogeneous adsorption. The maximum adsorption capacity fitted by Langmuir isotherm was 166.7 and 9.72 mg/g for Cd(II) ions (at optimum pH 6.5) and Cr(VI) ions (at optimum pH 2.5) respectively, using 1 wt.% PAMAM-MWCNTs/PVDF-HFP composite membrane. The adsorption capacities of Cd(II) ions were higher than those of Cr(VI) ions, which is thought to be due to the properties of the composite membrane material. According to the thermodynamic parameters, the Cd(II) and Cr(VI) ions adsorption process was spontaneous and endothermic. Reusability studies showed that PVDF-HFP composite membranes can be reused at least 4 times with an adsorption loss of only 5% for 1 wt.% PAMAMMWCNTs/PVDF-HFP composite membrane, confirmed by TGA and ICP-OES analysis. The 1 wt.% PAMAM-MWCNTs-PVDF-HFP composite membrane exhibited a higher selectivity towards Cd(II) over Cu(II), Zn(II) and Ni(II) in binary and quaternary metal adsorption studies.

<p dir="ltr">Inverse problems in infinite dimensions are ubiquitously encountered across the scien- tific disciplines. These problems are defined by the need to reconstruct continuous fields from incomplete, noisy measurements, which oftentimes leads to ill-posed problems. Almost universally, the solutions to these problems are constructed in a Bayesian framework. How- ever, in the infinite-dimensional setting, the theory is largely restricted to the Gaussian case, and the treatment of prior physical knowledge is lacking. We develop a new framework for Bayesian reconstruction of infinite-dimensional fields which encodes our physical knowledge directly into the prior, while remaining in the continuous setting. We then prove various characteristics of the method, including situations in which the problems we study have unique solutions under our framework. Finally, we develop numerical sampling schemes to characterize the various objects involved.</p>

Three-dimensional woven composites were developed to improve the through-thickness properties which conventional two-dimensional laminate composites currently lack. However, these textile composites generally show lower in-plane mechanical properties due to fibre crimping, and also encounter modelling difficulties due to the complex geometries. In this thesis, the static and fatigue mechanical behaviour of several types of 3D woven composites were experimentally characterised, the influence of the weave architecture on the mechanical performance was revealed, and meso/macro scale numerical models with improved failure criteria were developed to simulate the tensile behaviour of the 3D woven composites. The mechanical characterisation was conducted on six woven structures under tension, compression, and flexural loading, and were also carried out on two weaves under open-hole quasi-static tensile and fatigue loading. Digital image correlation and thermoelastic stress analysis were used to characterise the strain and damage development during static and fatigue loading. The testing results showed that the angle-interlock weave W-3 had higher in-plane quasi-static properties, lower notch sensitivity, higher fatigue damage resistance, but lower delamination resistance. The meso-scale model was developed on the unit cell of the woven structure and the macro-scale model (mosaic model) was created on the testing samples. Both un-notched and notched tensile behaviour were modelled for the angle-interlock weave W-3 and a one-by-one orthogonal weave W-1, and the difference between the predicted and experimental results was within 16% for the unit cell models and within 21% for the mosaic models. A modified failure criterion was developed to better simulate the damage behaviour of the notched macro-scale model and improved the predicted notched strength by 10-20%. Whilst further experimental investigation and improvement in the modelling techniques are still required, the data presented in this thesis provided an essential update for the current 3D woven composites research, and the presented models offered the potential to predict the damage behaviour of large 3D woven structures.

Over the last decade, many significant developments have been made to improve the active materials in a new generation of organic light emitting devices (OLEDs). Current OLED technology is focused on organo-transition metal complexes, which emit from the triplet excited state and exhibit bright phosphorescence. Efficient in devices have been reported using these luminescent materials, such as iridium and platinum complexes, however, rare metal abundance concerns, high price and toxicology have inspired the study of alternative phosphorescent materials, such as copper or silver complexes. In this research, novel copper complexes have been synthesized, such as trinuclear and mononuclear copper (I) complexes, using a range of ligands, such as alkynyl, phosphine alkynyl and pyridine ligands. The synthesised complexes have been characterised by with a range of techniques, such as UV/Vis absorption and emission spectroscopy, nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), cyclic voltammetry (CV) and scanning electron microscopy (SEM). Most of the copper complexes have shown very interesting luminescent properties in solution and solid state and some of them were studied for future application in a device.

Για περισσότερο από έναν αιώνα, οι εντερόκοκκοι προβληματίζουν τους ερευνητές ως προς την ταξινόμηση, τη λοιμογόνο ικανότητα, την επιδημιολογία και την ανθεκτικότητα τους στα αντιβιοτικά, αλλά και ως προς τη διασπορά τους στο περιβάλλον, αφού αυτή συνδέεται άμεσα με τη Δημόσια Υγεία. Οι εντερόκοκκοι, αποτελούν μέρος της φυσιολογικής εντερικής χλωρίδας ανθρώπων και ζώων και μπορούν να επιβιώσουν στο υδάτινο περιβάλλον για μεγάλο χρονικό διάστημα, κάτω από αντίξοες περιβαλλοντικές συνθήκες. Στον άνθρωπο προκαλούν βακτηριαιμία, ενδοκαρδίτιδα, λοιμώξεις του ουροποιητικού και άλλων συστημάτων. Μέσο διασποράς τους μπορεί να είναι και το περιβάλλον, γεγονός που καθιστά τη μελέτη της οικολογίας τους και την επιδημιολογική τους επιτήρηση ζωτικής σημασίας. Κατά τη χρονική περίοδο 10/2009-7/2010 στο νομό Αχαΐας, από 2115 δείγματα θαλάσσιου, επιφανειακού και πόσιμου ύδατος, 168 δείγματα βρέθηκαν θετικά για παρουσία εντερόκοκκων μετά από καλλιέργεια σε SB agar, δοκιμασία υδρόλυσης εσκουλίνης, αρνητική αντίδραση καταλάσης, ανάπτυξη σε 6,5% NaCl και βιοτυπία με Vitek. Επιπλέον, προσδορίστηκε η αντοχή στα αντιβιοτικά Penicilin, Erythromycin, Vancomycin, Teicoplanin, Chloramphenicol, Ciprofloxacin και Quinupristin/Dalfopristin. Ακολούθησε Pulsed-Field Gel Electrophoresis για την τυποποίηση των στελεχών σε κλώνους. Τέλος, πραγματοποιήθηκε συσχέτιση με αντίστοιχα κλινικά στελέχη ασθενών από το ΠΓΝΠ. Τα 121 από τα 168 δείγματα ανήκουν στο γένος των εντεροκόκκων, σύμφωνα με τον βιοχημικό φαινότυπο (50 E. faecalis, 43 E. faecium, 10 E. villorum, 9 E. gallinarum, 5 E. casseliflavus και 4 E.durans). To 85% των εντεροκόκκων ήταν ευαίσθητα στην Ρenicillin, το 17% στην Erythromycin, το 95% στην Vancomycin, το 100% στην Teicoplanin, το 70% στην Chloramphenicol και το 1% στην Ciprofloxacin. Συνολικά ταυτοποίηθηκαν σε κλώνους 76 από τα 105 στελέχη. Τα E. faecalis σε 2 ομάδες, τα E. faecium σε 5, τα E. gallinarum σε 3, τα E. villorum σε 1, τα E. casseliflavus σε 1 και τα E.durans σε 1. / For more than a century, there is great concern about enterococci, regarding the classification, pathogenicity, epidemiology and resistance to antibiotics, but also the distribution into the environment, since this fact is directly linked to Public Health. Enterococci are part of the normal intestinal flora of humans and animals and can survive in the aquatic environment for long periods under adverse environmental conditions. In humans, enterococci are leading causes of bacteraemia, endocarditis and urinary tract infections.. The environment is involved in their distribution, which makes the study of their ecology and the epidemiological surveillance of vital importance. During the period 10/2009-7/2010, in the geographic area of the prefecture of Achaia, 2115 samples from marine, surface and drinking water were collected and 168 of them were positive for the presence of enterococci according to inoculation in SB agar, bile-aesculin agar, negative catalase reaction, growth in 6,5% NaCl and biotyping with Vitek. Moreover, resistance to Penicillin, Erythromycin, Vancomycin, Teicoplanin, Chloramphenicol, Ciprofloxacin and Quinupristin / Dalfopristin was determined. Pulsed-Field Gel Electrophoresis was applied for clonal identification. Finally, a correlation with corresponding clonal types isolated from patients hospitalised at the University Hospital of Patras was performed. One hundrend and twenty-one out of 168 isolates were identified as enterococci, according to their biotypes (50 E. faecalis, 43 E. faecium, 10 E. villorum, 9 E. gallinarum, 5 E. casseliflavus and 4 E.durans). 85% of enterococci were sensitive to Penicillin, 17% to Erythromycin, 95% to Vancomycin, 100% to Teicoplanin, 70% to Chloramphenicol, and 1% to Ciprofloxacin. Overall 76 of the 105 strains were grouped. E. faecalis strains were classified into two PFGE types, E. faecium into five, E. gallinarum into three, E. villorum into one, E. casseliflavus into one and E.durans into one.