The geometrical accuracy of a custom artificial intervertebral disc implant manufactured using Computed Tomography and Direct Metal Laser Sintering

Published ArticleRapid Manufacturing (RM) has emerged over the past few years as a potential technology to successfully produce patient-specific implants for maxilla/facial and cranial reconstructive surgeries. However, in the area of spinal implants, customization has not yet come to the forefront and with growing capabilities in both software and manufacturing technologies, these opportunities need to be investigated and developed wherever possible. The possibility of using Computed Tomography (CT) and Rapid Manufacturing (RM) technologies to design and manufacture a customized, patient-specific intervertebral implant, is investigated. Customized implants could aid in the efforts to reduce the risk of implant subsidence, which is a concern with existing standard implants. This article investigates how accurately the geometry of a customized artificial intervertebral disc (CAID) can represent the inverse geometry of a patient's vertebral endplates. The results indicate that the endplates of a customized disc implant can be manufactured to a calculated average error of 0.01mm within a confidence interval of 0.022mm, with 95% confidence, when using Direct Metal Laser Sintering

The mission of the local church amidst social disruption and transition : a study of the Ilitha and Ndevana communities in the Eastern Cape

The policy of Separate Development and its forceful implementation by the Nationalist Government from the !960's and into the 1980's resulted in the resettlement of thousands of Africans in the 'homeland' Ciskei in the Eastern Cape. All these changes had a profound and very often a disruptive influence on the lives of those involved. People's ability to survive amidst these circumstances, was tested to the limit. This study looks at the role of the local Christian faith community in supporting its members during these rapid and disruptive socioeconomic and political changes. The study is confined to two congregations of the Uniting Reformed Church in Southern Africa in Ilitha and Ndevana in the Eastern Cape. Following an introductory chapter, Chapter 2 gives a historical outline of developments in the broader Ciskei. Attention is also given to demographic, social and economic conditions. Chapter 3 describes the culture and feeling of despair, powerlessness and mistrust that is deeply entrenched in the minds of many people in the community due to depressive socio-economic situations. Chapter 4 gives an overview of the churches in the area and describes the supportive structures and actions of two churches in the Ilitha-Ndevana area. No instant solutions are offered to members but through mutual support they find a sense of belonging and encouragement in the midst of their hardship. In Chapter 5 a model for the mission of the local church in a context of social and economic change and disruption, is presented. It is shown how the image of Christianity and the Gospel have been distorted and misused in the past through the entanglement of mission and colonialism, a negative attitude towards African culture, and by contributing to the subordination of women in society. A vision that people in Africa can have peace and dignity and become self-reliant is proposed. Within the local faith community this vision is built on an understanding of God as the weak and suffering Lord, on fellowship and mutual support, a new reading of the Bible, a practical community based spirituality, and an emphasis on healing.Die daarstelling en .kragdadige toepassing van die beleid van Afsonderlike Ontwikkeling vanaf die 1960's tot·die 1980's het tot gevolg_gehad dat duisende Swart Suid-AftilCaners hervestig is in die Ciskei-tuisland in die Oos-Kaap. Al hierdie veranderinge het verreikende en baie dikwels ontwrigtende gevolge op die betrokkenes gehad. Mense se vermoens om binne hierdie omstandighede te oorlee:t: is tot die uiterste beproef. Hierdie studie kyk na die rol van die plaaslike · Cbristelike. geloofsgemeenskap in die ondersteuning van sy lede tydens snelle en ontwrigtende sosiale, ekonomiese en politieke veranderinge. Die studie is beperk tot twee gemeentes van die Verenigende Gereformeerde Kerk in Suider-Aftika in Ilitha en Ndevana in die Oos-Kaap. Na 'n inleidende hoofstuk, gee hoofstuk 2 'n historiese oorsig van ontwikkelinge in die breere Ciskei-gebied. Aandag word ook gegee aan demografriese, sosiale en ekonomiese toestande. Hoofstuk 3 beskryf 'n kultuur en gevoel van moedeloosheid, magteloosheid en wantroue wat, as gevolg van neerdrukkende sosiaal-ekonomiese toestande, diep in menige mense se gemoedere vasgele is. Hoofstuk 4 gee 'n oorsig oor die kerke in die gebied en beskryf die ondersteunende strukture en optrede in twee gemeentes in die Ilitha-Ndevana area. Geen kitsoplossings word aan lede aangebied nie, maar deur onderlinge steun vind hulle geborgenheid en bemoediging te midde van swaarkry. In hoofstuk 5 word 'n model aangebied vir die missie van die plaaslike kerk te midde van sosiale en ekonomiese veranderinge en ontwrigting. Daar word aangetoon hoe die beeld van die Christendom in die verlede verwring en misbruik is deur: die verstrengeling van sending en kolonialisasie; 'n negatiewe houding teenoor kultuur in Afrika; en deur by te dra tot die ondergeskikte posisie van vroue in die samelewing. 'n Visie dat die mense van Afrika vrede en menswaardigheid kan geniet en self onderhoudend kan raak, word voorgestel. Binne die plaaslike geloofsgemeenskap word aan hierdie visie gebou deur 'n begrip van God as die magtelose en lydende Here, deur onderlinge gemeenskap en ondersteuning, 'n nuwe lees en begrip van die Bybel, 'n praktiese gemeenskaps-gerigte spiritualiteit en 'n beklemtoning van heling en herstel.Christian Spirituality, Church History and MissiologyD.Th. (Missiology

From “Smart in the Box” to “Smart in the City”: Rethinking the Socially Sustainable Smart City in Context

18 months embarg

Introducing Shaping Smart for Better Cities

Hence the volume offers an intellectual resource that expands on the current literature, but also provides a pedagogical resource to universities as well as a reflective opportunity for practitioners

Towards an agenda of place, local agency-based and inclusive smart urbanism

"The volume explores the question of what it means for a city to be 'smart', raises some of the tensions emerging in smart city developments, and considers the implications for future ways of inhabiting and understanding the urban condition ..

Optical observations of "hot" novae returning to quiescence

We have monitored the return to quiescence of novae previously observed in outburst as supersoft X-ray sources, with optical photometry of the intermediate polar (IP) V4743 Sgr and candidate IP V2491 Cyg, and optical spectroscopy of these two and seven other systems. Our sample includes classical and recurrent novae, short period (few hours), intermediate period (1-2 days) and long period (symbiotic) binaries. The light curves of V4743 Sgr and V2491 Cyg present clear periodic modulations. For V4743 Sgr, the modulation occurs with the beat of the rotational and orbital periods. If the period measured for V2491 Cyg is also the beat of these two periods, the orbital one should be almost 17 hours. The recurrent nova T Pyx already shows fragmentation of the nebular shell less than 3 years after the outburst. While this nova still had strong [OIII] at this post-outburst epoch, these lines had already faded after 3 to 7 years in all the others. We did not find any difference in the ratio of equivalent widths of high ionization/excitation lines to that of the Hbeta line in novae with short and long orbital period, indicating that irradiation does not trigger high mass transfer rate from secondaries with small orbital separation. An important difference between the spectra of RS Oph and V3890 Sgr and those of many symbiotic persistent supersoft sources is the absence of forbidden coronal lines. With the X-rays turn-off, we interpret this as an indication that mass transfer in symbiotics recurrent novae is intermittent.Comment: In press in Monthly Notices of the Royal Astronomical Societ

The effect of passive immunization on active immunity against Clostridium perfringens type D in lambs

Lambs in different stages of development of active immunity against Clostridium perfringens type D were treated with partially purified immunoglobulin in an attempt to superimpose a passive immunity on an existing or developing active immunity. Three different studies were undertaken to determine the impact of partial purified immunoglobulins on these vaccinated animals. In 2 of the 3 studies, active immunity was induced by administering the normal routine enterotoxaemia vaccinations and allowing the basic immunity to become established, for a period ranging from 2 weeks for the animals in study 1 and 4 months for those in study 2, before passive immunization with the partially purified immunoglobulins took place. An increase in the epsilon antibody titre occurred in each of the 2 studies after the animals were passively immunized with immunoglobulin, though this increase was not statistically significant (P>0,05). In the 3rd study, when the animals were given the initial vaccination of the Onderstepoort enterotoxaemia oil adjuvant vaccine together with the immunoglobulin, an immediate increase in the epsilon antitoxin titre occurred that was statistically significant (P<0,05) 2-14 days after administration. No negative effects were noted on the development of an initial active immunity or an existing active immunity against Clostridium perfringens type D when they were passively immunized with partially purified immunoglobulin.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn2014ab201

Making space for drones: the contested reregulation of airspace in Tanzania and Rwanda

In this paper we examine how certain African countries have become testbeds for new forms of drone infrastructure and regulation, driven by the overlapping interests of governments, drone operators, and international development agencies. In particular we explore the factors that have led to the development of an advanced medical delivery network in Rwanda and contrast that with the closing down of airspace for drones in Tanzania. The paper makes a distinctive contribution to research on the ongoing constitution and enclosure of dronespace as a sphere of commercial and governmental activity

On handling urban informality in southern Africa

In this article I reconsider the handling of urban informality by urban planning and management systems in southern Africa. I argue that authorities have a fetish about formality and that this is fuelled by an obsession with urban modernity. I stress that the desired city, largely inspired by Western notions of modernity, has not been and cannot be realized. Using illustrative cases of top–down interventions, I highlight and interrogate three strategies that authorities have deployed to handle informality in an effort to create or defend the modern city. I suggest that the fetish is built upon a desire for an urban modernity based on a concept of formal order that the authorities believe cannot coexist with the “disorder” and spatial “unruliness” of informality. I question the authorities' conviction that informality is an abomination that needs to be “converted”, dislocated or annihilated. I conclude that the very configuration of urban governance and socio-economic systems in the region, like the rest of sub-Saharan Africa, renders informality inevitable and its eradication impossible