Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Bacterial colonisation and biofilm formation onto total hip replacement femoral stems remain a serious complication detrimental to the success of total hip arthroplasty. Current treatment procedures are accompanied by a heavy financial burden and morbidity for the patient while failing to guarantee a successful outcome with no reinfection. In fact, infection rates after revision surgeries are typically higher than those for primary hip arthroplasties. This study investigates conceptual drug delivery channels to be incorporated within cementless femoral stems by applying additive manufacturing as enabler technology. Drug delivery from these features is aimed at both prophylaxis and treatment of infection, with the latter emphasising the concept of creating a reinforceable antimicrobial depot inside the implant. The novelty lies in facilitating the administration of multiple drug dosages from within the implant instead of the once-off implant-based release strategies currently employed. Samples containing internal channels were designed based on analogies to drug delivery studies reporting on the commercial antibiotic loaded bone cement, Palacos R+G loaded with gentamicin. These samples were manufactured by LaserCUSING® from Ti-6Al-4V ELI powder. For prophylactic proof of concept, testing the channels were filled with Palacos R+G and challenged with two clinical isolates of Staphylococcus aureus in a bacterial growth inhibition study. Gentamicin-susceptible S.aureus Xen 36 was prevented from colonising for a minimum of 72 hours, whereas gentamicin resistant S.aureus Xen 31 reached the material within 24 h, signifying the importance of drug selection according to pathogen. Hence, a solution of vancomycin in phosphate buffered saline pH 7.4 was used during in vitro reservoir release testing. Three dosage injections were made into each of six samples during a cumulative incubation period of 100 h. A biocompatible 5,000 Da molecular weight cut off polyethersulfone nanoporous membrane was employed as release rate-controlling device. Released vancomycin was quantified with reversed phase high performance liquid chromatography. The resulting release profile was characterised by means of the Korsmeyer-and-Peppas model for diffusion based drug delivery. Constraint diffusion was identified as the mechanism controlling release, implying interplay between Fickian diffusion and polymer relaxation for effecting vancomycin release from within the reservoir. The concept created in this study provides a basis towards the development of full scale intelligent implants with multiple dose in situ drug delivery capabilities. Implants incorporating this concept could aid in the perpetual struggle against infection by providing a new strategy for delivery of high level antibiotics directly to the site of infection. / AFRIKAANSE OPSOMMING: Kolonisering van bakterieë en die vorming van biofilms op totale heupvervanging femorale stamme bly ʼn ernstige komplikasie tot die sukses van ʼn totale heupvervanging. Huidige behandelingsprosedures gaan gepaard met ʼn swaar finansiële las en infeksies vir die pasiënt sonder versekering van ʼn suksesvolle uitkoms. Die voorkoms van infeksie is tipies hoër vir revisie prosedures as vir primêre heupvervangings. Hierdie studie ondersoek konseptuele dwelmvoorsieningskanale wat in sementvrye femorale stamme geïnkorporeer kan word deur middel van toevoegingsvervaardiging as bemagtigingstegnologie. Dwelmtoediening deur hierdie strukture is gemik op beide voorkoming en behandeling van infeksie met ʼn klem op die konsep van ʼn herlaaibare antimikrobiese depot in die implantaat. Die nuwigheid lê in die fasilitasie van toediening van veelvuldige dwelm dosisse vanaf binne die implantaat in plaas van die huidige eenmalige implantaatgebaseerde toedieningstrategieë. Die ontwerp van monsters wat interne kanale bevat is baseer op vergelykings met literatuur op kommersiële beensement, Palacos R+G, wat met gentamisien belaai is. Hierdie monsters is vervaardig met LaserCUSING® van Ti-6Al-4V ELI poeier. Kanale is gevul met Palacos R+G en uitgedaag met twee kliniese isolate van Staphylococcus aureus in ʼn bakteriële groei inhibisie studie. Gentamisien-sensitiewe S.aureus Xen 36 is verhoed tot kolonisasie vir ʼn minimum van 72 uur, terwyl gentamisien-weerstandige S.aureus Xen 31 die materiaal binne 24 uur bereik het. Vervolgens was ‘n oplossing van vankomisien in fosfaatbuffer soutoplossing pH 7.4 gebruik tydens in vitro vrystellingstoetse. Drie dosisse inspuitings is in elk van ses monsters oor ʼn inkubasietydperk van 100 uur toegedien. ʼn Biokompatibiele 5,000 Da molekulêre massa afsnypunt polietersulfoon nanoporeuse membraan is as vrystellingskoers regulerende apparaat gebruik. Vrygestelde vankomisien is gekwantifiseer met omgekeerde fase hoë verrigting vloeistof-chromatografie. Die vrystellingsprofiel is gekarakteriseer met die Korsmeyer-en-Peppas model vir diffusie gebaseerde dwelmtoediening. Beperkte diffusie is geïdentifiseer as die meganisme wat vrystelling beheer. Dit impliseer ʼn tussenspel in Fickiaanse diffusie en polimeer verslapping vir die tot stand bring van vankomisien vrystelling vanaf binne die reservoir. Hierdie konsep van die studie verskaf ʼn basis vir die ontwikkeling van volskaalse intelligente implantate met ʼn veelvuldige in situ dwelmtoedienings vermoë. Implantate met hierdie konseptuele strukture kan steun gee aan die voortdurende stryd teen infeksie deur ʼn nuwe strategie daar te stel vir die toediening van hoë vlak antibiotika direk by die infeksie area.

ABSTRACT The purpose of this study was to explore the preferred information sources and delivery channels for receiving agronomic crop related information for farmers, agricultural retailers, and private crop consultants in Mississippi. The Mississippi State Extension Agronomic Crops Team can use this information to better serve their agronomic crop clients throughout the state of Mississippi. An electronic survey was developed and disseminated at the Mississippi State Row Crops Short Course, Winter Producer Meetings, and Farm Trade Shows to farmers, agricultural retailers, and private crop consultants who attended throughout Mississippi (n=298). The highest-ranking interpersonal information source was MSU Extension, followed by agricultural retailers, and crop consultants. The lowest ranking interpersonal information sources were other farmers, seed and chemical companies, and government agencies. The highest ranking information delivery channels were email, text messaging, and the Mississippi Crops Blog. The lowest ranking information delivery channels were postal mail, Facebook, Instagram, and Twitter. Face-toace conversations, private consultants, and field days were the highest rated information source preferences. In contrast, respondents rated television and radio the lowest. Respondents were asked to give a numeric ranking on where they would fall on adopting a new agricultural technology (e.g. smart phone crop app). The majority of respondents placed themselves in the “Early Majority” group as it relates to Rogers Diffusion of Innovation. The smallest percentage placed themselves in the “Laggards” group. Internet use among farmers was found to be influenced by age, highest level of education, internet connection type, and other devices used. Findings in this study support the Uses and Gratifications Theory. The majority of respondents still place value in the MSU Extension Agronomic Crops Team when it comes to frequency of contact. Respondents number one answer was making contact ten or more times a year with the appropriate Crops Specialist for their agronomic crops needs. Extension educators should remember that not all of their clientele are equally connected to the internet. Marketing efforts for programs and educational materials available only online are not being accessed by all potential clientele. Programs targeting older clientele should be marketed using other methods in addition to the internet.

<p>Purpose – The growing importance of use of Internet banking as another service delivery channel by banks to their customers lead to a number of supposition and deductions been made on the value creation of Internet banking and its extent of use. In the light of this, a profound and comprehensive study was conducted with the aim to first, determine the extent of use of Internet banking in Sweden, second, to validate the conjecture and the anecdote inferences that Internet banking provides values to both the bank and its customers.</p><p>Design/Methodology/approach - To test the validity of the conjecture and the anecdote inferences made over the years, the author use data collected in two folds. One set was collected from financial institution “the big four banks” and the other set from 60 bank customers out of the 90 questionnaires administered.</p><p>Findings - The results provide first, evidence of the high rate of adoption of Internet banking in Sweden, second, the values the banks and its customers have enjoyed since the advent of Internet banking.</p><p>Research limitations/implications - Although this exploratory study approach may have validated the proposed model, further research into other cities is required to generalize these findings as this study has the limitation of using only Stockholm and the number of respondents used.</p><p>Originality/value - The findings contribute and support several other studies that pointed to the fact that use of Internet banking channel of delivery is on the increase, and its value creation far exceed all other service delivery channels; provide critical implications for managers of financial institutions, Internet service providing firms, government and highlight directions for future research.</p><p>Keywords Internet banking, Online banking, Service delivery channels, Technology-based, Enabled-service, Product-service Continuum</p>

Purpose – The growing importance of use of Internet banking as another service delivery channel by banks to their customers lead to a number of supposition and deductions been made on the value creation of Internet banking and its extent of use. In the light of this, a profound and comprehensive study was conducted with the aim to first, determine the extent of use of Internet banking in Sweden, second, to validate the conjecture and the anecdote inferences that Internet banking provides values to both the bank and its customers. Design/Methodology/approach - To test the validity of the conjecture and the anecdote inferences made over the years, the author use data collected in two folds. One set was collected from financial institution “the big four banks” and the other set from 60 bank customers out of the 90 questionnaires administered. Findings - The results provide first, evidence of the high rate of adoption of Internet banking in Sweden, second, the values the banks and its customers have enjoyed since the advent of Internet banking. Research limitations/implications - Although this exploratory study approach may have validated the proposed model, further research into other cities is required to generalize these findings as this study has the limitation of using only Stockholm and the number of respondents used. Originality/value - The findings contribute and support several other studies that pointed to the fact that use of Internet banking channel of delivery is on the increase, and its value creation far exceed all other service delivery channels; provide critical implications for managers of financial institutions, Internet service providing firms, government and highlight directions for future research. Keywords Internet banking, Online banking, Service delivery channels, Technology-based, Enabled-service, Product-service Continuum