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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Construction and evaluation of synthetic carbonate plugs. / Construção e avaliação de plugues sintéticos carbonáticos.

Arismendi Florez, Jhonatan Jair 06 December 2018 (has links)
Many of Brazil\'s pre-salt basins are located in ultra-deep waters, and the high heterogeneities of its offshore carbonate reservoirs make the extraction of representative rock samples difficult, risky and expensive. Synthetic plugs are required to understand oilfield properties and the behavior of oil in reservoirs where natural plugs cannot be extracted. Specifically, in cases where it is necessary to reproduce representative mineralogical and petrophysical characteristics from carbonates reservoir, it is evident that there are a lack of publications focusing on synthetic plug construction. In this work, the construction of synthetic plugs is studied, using a combination of published methodologies to achieve an alternative construction of synthetic carbonate plugs for laboratory scale studies. The obtained plugs used a procedure based on disintegrated rock matrices with known particle sizes and particle size ratio, uniaxial compaction with controlled load force and velocity, CaCO3 solubility control by changing temperature and pH and bonding material. Consolidation, wettability and petrophysical properties of the synthetic plugs were evaluated to characterize them. Generally, it was observed that the porosity and permeability features of the synthetic plugs were within the range of carbonate reservoirs. However, without reproducing a heterogeneous pore structure normally present in natural samples. On the other hand, wettability properties of the resulted synthetic plugs were similar to the natural carbonate plugs. Further studies are necessary to obtain more similar chemical and petrophysical properties to the natural samples. / A localização em águas ultra profundas das reservas petrolíferas do pré-sal brasileiro e a alta heterogeneidade dos seus reservatórios carbonáticos dificultam a aquisição de uma amostra de rocha representativa, além de ser uma operação de risco e de alto dispêndio. Plugues sintéticos são utilizados para compreensão das propriedades dos campos petrolíferos e para avaliação do comportamento dos hidrocarbonetos em reservatórios onde plugues reais não podem ser adquiridos. Especificamente, nos casos onde são necessários reproduzir características representativas mineralógicas e petrofísicas dos reservatórios carbonáticos, sendo notório a falta de publicações voltada para construção de plugues sintéticos. No presente trabalho, estudou-se a construção de plugues sintéticos empregando metodologias já difundidas, visando a construção de plugues carbonáticos sintéticos para utilização em escala laboratorial. Os plugues obtidos foram construídos utilizando matrizes de rochas desintegradas com tamanhos e proporções de partículas conhecidos, compactação uniaxial com força e velocidades controladas e controle de solubilidade de CaCO3, variando apenas temperatura, pH e proporções de material cimentante. Foram avaliadas as propriedades petrofísicas, a molhabilidade e a consolidação dos plugues sintéticos para posterior caracterização dos mesmos. Comumente, observou-se que os valores de porosidade e permeabilidade dos plugues sintéticos se encontravam dentro do intervalo de valores obtidos em reservatórios carbonáticos reais. No entanto, não reproduziram a estrutura heterogênea dos poros, normalmente presente em amostras de rochas naturais. Em contrapartida, as propriedades de molhabilidade dos plugues sintéticos se apresentaram análogas aos plugues de rochas carbonáticas naturais. Estudos complementares são necessários para obtenção de propriedades químicas e petrofísicas mais próximas das amostras reais.
12

Construction and evaluation of synthetic carbonate plugs. / Construção e avaliação de plugues sintéticos carbonáticos.

Jhonatan Jair Arismendi Florez 06 December 2018 (has links)
Many of Brazil\'s pre-salt basins are located in ultra-deep waters, and the high heterogeneities of its offshore carbonate reservoirs make the extraction of representative rock samples difficult, risky and expensive. Synthetic plugs are required to understand oilfield properties and the behavior of oil in reservoirs where natural plugs cannot be extracted. Specifically, in cases where it is necessary to reproduce representative mineralogical and petrophysical characteristics from carbonates reservoir, it is evident that there are a lack of publications focusing on synthetic plug construction. In this work, the construction of synthetic plugs is studied, using a combination of published methodologies to achieve an alternative construction of synthetic carbonate plugs for laboratory scale studies. The obtained plugs used a procedure based on disintegrated rock matrices with known particle sizes and particle size ratio, uniaxial compaction with controlled load force and velocity, CaCO3 solubility control by changing temperature and pH and bonding material. Consolidation, wettability and petrophysical properties of the synthetic plugs were evaluated to characterize them. Generally, it was observed that the porosity and permeability features of the synthetic plugs were within the range of carbonate reservoirs. However, without reproducing a heterogeneous pore structure normally present in natural samples. On the other hand, wettability properties of the resulted synthetic plugs were similar to the natural carbonate plugs. Further studies are necessary to obtain more similar chemical and petrophysical properties to the natural samples. / A localização em águas ultra profundas das reservas petrolíferas do pré-sal brasileiro e a alta heterogeneidade dos seus reservatórios carbonáticos dificultam a aquisição de uma amostra de rocha representativa, além de ser uma operação de risco e de alto dispêndio. Plugues sintéticos são utilizados para compreensão das propriedades dos campos petrolíferos e para avaliação do comportamento dos hidrocarbonetos em reservatórios onde plugues reais não podem ser adquiridos. Especificamente, nos casos onde são necessários reproduzir características representativas mineralógicas e petrofísicas dos reservatórios carbonáticos, sendo notório a falta de publicações voltada para construção de plugues sintéticos. No presente trabalho, estudou-se a construção de plugues sintéticos empregando metodologias já difundidas, visando a construção de plugues carbonáticos sintéticos para utilização em escala laboratorial. Os plugues obtidos foram construídos utilizando matrizes de rochas desintegradas com tamanhos e proporções de partículas conhecidos, compactação uniaxial com força e velocidades controladas e controle de solubilidade de CaCO3, variando apenas temperatura, pH e proporções de material cimentante. Foram avaliadas as propriedades petrofísicas, a molhabilidade e a consolidação dos plugues sintéticos para posterior caracterização dos mesmos. Comumente, observou-se que os valores de porosidade e permeabilidade dos plugues sintéticos se encontravam dentro do intervalo de valores obtidos em reservatórios carbonáticos reais. No entanto, não reproduziram a estrutura heterogênea dos poros, normalmente presente em amostras de rochas naturais. Em contrapartida, as propriedades de molhabilidade dos plugues sintéticos se apresentaram análogas aos plugues de rochas carbonáticas naturais. Estudos complementares são necessários para obtenção de propriedades químicas e petrofísicas mais próximas das amostras reais.
13

The development of a wall-less plug for planting stock of forest trees.

Schuermans, Jean. 14 November 2013 (has links)
High output commercial nurseries that cater for the forestry industry are continuously challenged to efficiently and cost effectively produce good quality planting stock to establish large plantations. Currently, South African commercial nurseries produce planting stock in solid compartmentalized trays. One of the major drawbacks of these containers is the susceptibility of trees to root deformation following outplanting, combined with the need for the return of empty containers to the nursery. A potential solution to these challenges is the introduction of wall-less plugs for the production of planting stock. Wall-less plugs are volumes of growing medium, usually cylindrical in shape, devoid of an impenetrable wall in which a plant can grow and establish itself. Such plugs may enable the production of planting stock with improved root systems, without the need for the return of empty containers after outplanting. In this research four prototypes of wall-less plugs were developed, produced on a small scale and tested. These were: 1) Paper-maché plugs made using the original WRIBLOK protocol whereby composted pine bark was bound together with repulped newspaper, 2) Sponge blocks, 3) Hessian bags and 4) Covetan bags. The performance of these prototype wall-less plugs was compared with the performance of four tray types used commercially by the forestry industry: 1) Poly 128 shallow, 2) Poly 98 deep, 3) Unigro 128 and 4) Sappi 49. These are polystyrene and polypropylene-based containers. Of these containers the Unigro 128 and Sappi 49 containers were of similar performance. Performance in terms of height and root collar diameter increase over ten weeks from the time of sowing of the paper-maché plugs was similar to that of the Unigro and Sappi 49 containers. The sponge block, Hessian bags and Covetan bags produced inferior quality planting stock compared to the other treatments tested. Although little progress was made in the ability to describe how one root system differs from another in terms of their branching patterns, a technique was developed to determine root surface area by image analysis software that is freely available. This method may prove useful for further research and for determining seedling quality in commercial nurseries. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
14

Computational study of arc discharges : spark plug and railplug ignitors [sic]

Ekici, Özgür, 1973- 24 June 2011 (has links)
Not available / text
15

Re-vegetation dynamics of land cleared of Acacia mearnsii (black wattle)

Glaum, Melanie Jane. January 2005 (has links)
The overall aim of the study was to investigate re-vegetation of disturbed sites, using nursery grown plugs (from seedling trays) of Themeda triandra, Heteropogon contortus and Hyparrhenia dregeana in order to reach practical management guidelines for re-vegetation using indigenous grass plugs. A number of field trials were set up at Kamberg Nature Reserve (29°24'S, 29°40'E) on a site that was clear felled of A. mearnsii in October 1997. The trials were established in January 1998 and January 1999. A total of approximately 52 ,000 nursery raised plugs of T. triandra, H. contortus and H. dregeana were planted into an area of approximately 7,000 m2 . In the planting density trial , plugs of H. dregeana only and a combination of T. triandra/H. contortus were planted at 15 cm and 30 cm spacings. The T. triandra/H. contortus combination at 30 spacing showed the greatest survival and lateral plant growth (tiller number and basal area) and this combination is thus recommended. In the over-sowing trials, the H. dregeana and T. triandra/H. contortus combination at both 15 cm and 30 cm spacing were over-sown with E. curvula. The survival and lateral growth of the T. triandra/ H. contortus combination at 30 cm was again greater than the other treatments. Over-sowing with E. curvula suppressed the survival and lateral growth of the planted plugs across all treatments compared to not over-sowing. The over-sown conditions showed a significant decrease in the diversity of the plots, both in the number of species present and the Shannon diversity index. An area that had been cleared of A. mearnsii and sown to E. curvula 25 years previously was shown to have a lower number of species than the neighbouring veld. Nursery raised plugs of T. triandra were planted into the mature E. curvula in an attempt to improve the biodiversity of these areas. To re-introduce T. triandra into these E. curvula swards the plugs must be planted into the centre of a gap rather than around the base of an E. curvula plant. For improved survival of the plugs the E. curvula tufts must be clipped, while for best lateral growth the E. curvula tufts must be sprayed with a glyphosate herbicide three months prior to planting and clipping. However, the added expense of spraying and clipping is not warranted as the clipped treatments also showed good growth. Transplant shock is common when planting nursery raised plugs out into the field, as there is a relatively small root volume in the plug compared to the above ground leaf biomass. Alleviation of moisture stress at planting using a starch based polymer with high water holding capacity (Terrasorb®) and a white, needle punched geo-fabric (Agrilen®) to provide a seven day period of artificial shade after planting did not show significant improvements over the control with regards to survival or plant growth. Thus these methods of moisture amelioration are not recommended in revegetation through planting of plugs at this study site. A trial was established to investigate the biomass production of six different treatments to determine their potential to support a fire. The total biomass for the plots which were over-sown by E. tef and planted to only H. dregeana were on average sufficient for a fire, but there was a discontinuous fuel load across these plots, especially in the replications that had very low survival rates and thus these plots could not be burnt. The control and herbicide sprayed plots also showed sufficient fuel load for a fire, but this fuel load was made up of A. mearnsii saplings and bramble with very little grass cover and thus a fire would not have burnt through these plots either. The T. triandra/H. contortus combination did not produce sufficient fuel load, due to poor survival. Thus only the plots over-sown with E. curvula were able to burn in this trial and as a burning trial per se the trial was abandoned. Seed bearing hay (thatch) was collected in early summer (December 1997) and late summer (April 1998). Both times of year of harvesting proved to be successful in terms of grass cover, although the early harvested thatch had a greater number of species per plot. The Shannon diversity indexes of the two treatments were not significantly different. The multi-response permutation procedure technique confirmed that there was a compositional difference between the treatments. By the end of the trial Harpochloa falx and T. triandra and H. dregeana were indicators for the early and the late harvested thatch respectively. Comparing the thatching trial and the planting density trial indicated that the T. triandra/H. contortus combination at 30 cm spacing would be recommended to maximize biodiversity. The summer months have been shown to be the best time to plant the plugs, although the actual success will be dependant on the conditions within a particular year. The plugs should not be kept in the nursery for longer than three months and larger plugs (96 seedlings per tray) should be used. Nursery raised plugs of T. triandra and H. contortus were planted in an equal mix in an area that was cleared of A. mearnsii in 1996. By June 1998 661 H. contortus seedlings and 14 T. triandra seedlings had germinated naturally. The November 1998 population consisted of 418 H. contortus seedlings and 18 T. triandra seedlings. By May 2000 the June 1998 population showed a survival of 78.4% and the November 1998 population showed a survival of 91 .1 %. In the various trials, the ability of the nursery raised plugs used for re-vegetation to suppress the regrowth of A. mearnsii was investigated by determining the number of A. mearnsii seedlings per metre squared. The plant spacing and species of plugs used did not have a significant effect on the number of A. mearnsii seedlings per metre squared. Over-sowing with E. curvula did, however, significantly suppress the wattle re-growth. In the thatching trial the early harvested plots showed lower numbers of A. mearnsii per metre squared than the late harvest plots, as they were covered with a thick layer of thatch soon after the A. mearnsii was cleared which suppressed the A. mearnsii re-growth. Although E. curvula is able to produce a high biomass and suppress the A. meansii seedlings, it has a detrimental effect on the biodiversity of the area. Therefore, in conservation areas, where biodiversity is of great importance the planted plugs (at 30 cm spacing) or seed bearing hay must be used in preference to sowing E. curvula , although it must be remembered that greater follow up control is likely to be needed with planted plugs or seed bearing hay. The area must be planted or thatched as soon as possible after clear felling to provide competition for the A. mearnsii seedlings. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
16

Adi??o de chamote de velas de igni??o inserv?veis na obten??o de cer?mica branca a base de alumina

Palma, Aldemiro Jos? Rocha 21 January 2010 (has links)
Made available in DSpace on 2014-12-17T14:57:59Z (GMT). No. of bitstreams: 1 AldemiroJRP_DISSERT.pdf: 1779400 bytes, checksum: 8a5467983a7427bc6b96f7baa7868609 (MD5) Previous issue date: 2010-01-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work presents research into the addition of chamotte obtained from the ceramic isolator of unusable spark plugs in formulations of material mixes for standard white ceramic material with aluminum oxide bases. After the physical chemical characterization of the primary materials, standard clay and the chamotte, three mixtures were prepared with concentrations of 10, 20 and 30% chamotte by weight in relation to the standard clay. The test samples underwent heating at a rate of 30 0C/min to levels that included 100o , 200o , 300o, 400o, 500o e 600 0C and also we submitted to three distinct burn temperatures: 1450o, 1500o e 1550 0C, remaining at these temperatures for 2 hour periods. After sintering, the physical and microstructural properties of the different test samples were measured and analyzed. The results show that the materials obtained present good technical properties and that the chamotte can be reutilized as an additive in the production of white ceramic material with an aluminum oxide base / Neste trabalho estudou-se a influ?ncia da adi??o de chamote obtido do isolador cer?mico de velas de igni??o inserv?veis na formula??o de massas de cer?mica branca a base de alumina. Ap?s caracteriza??o f?sico-qu?mica das mat?rias-primas, argila-padr?o e chamote, foram preparadas tr?s formula??es de concentra??es 10, 20 e 30% em peso de chamote em rela??o ? argila-padr?o. Os corpos-de-prova foram submetidos ao aquecimento numa taxa de 30 0C/min em patamares de 100? , 200? , 300? , 400? , 500? e 600 0C e queimados em tr?s temperaturas distintas a 1450? , 1500? e 1550 0C, permanecendo 2 horas na temperatura de patamar. Ap?s as sinteriza??es, as propriedades f?sicas e a evolu??o microestrutural de fases dos corpos-de-prova foram mensuradas e discutidas. Os resultados mostraram que os materiais obtidos apresentam boas propriedades e que o chamote pode ser reaproveitado como aditivo na produ??o de cer?micas brancas a base de alumina
17

Patterns and mechanisms : postcopulatory sexual selection and sexual conflict in a novel mating system

Friesen, Christopher R. 04 December 2012 (has links)
Postcopulatory sexual selection—sperm competition and cryptic female choice—has become a major area of research over the past 40 years. Within this field there are many outstanding questions at every level of analysis, from proximate to ultimate. The fitness consequences for both sexes in the period after copulation and before fertilization are considerable, but are obscured within the female reproductive tract. Our understanding of postcopulatory mechanisms is especially sparse in taxa other than birds and insects. Nearly nothing is known in reptiles except that multiple paternity is common and widespread, and often results from long-term sperm storage across breeding seasons. We present some of the very first data on the determinants of fertilization success in the context of sperm competition in reptiles, a group that accounts for 30% of terrestrial vertebrates. In the first chapter, "Asymmetric gametic isolation between two populations of red-sided garter snakes", we discuss the use of between-population crosses to reveal gametic isolation. The effect of population density and operational sex ratios on mating systems and the speciation process has fueled theoretical debate. We attempted to address these issues using two populations of red-sided garter snakes (Thamnophis sirtalis parietalis) from Manitoba, Canada. Our study populations differ markedly in their density mating aggregations, with a 10-fold difference between them. Using microsatellite markers for paternity analysis of litters produced from within and between population crosses. We found that the population with highest aggregation density, and presumably with the highest level of sexual conflict (i.e., when the evolutionary interests of the sexes differ) over mating, was also the population that exhibited homotypic sperm precedence. The less dense population showed a distinct postcopulatory male-size advantage. We also demonstrated that sperm stored within the female over hibernation can father 20-30% of offspring in a litter. In the second chapter, "Sperm competition and mate-order effects in red-sided garter snakes", we test whether females use mate-order effects to ensure that a larger (fitter) male will sire her offspring. Does that second male should have precedence in sperm competition? We tested for second-male precedence using singly-mated females that mated with a second male. Average proportion of paternity was shared equally among the first (P₁, i.e., proportion of offspring from a litter fathered by the first male to mate) and second males (P₂) to mate, and stored sperm (P[subscript ss]). This may be a case where last male precedence breaks down with more than two males. All females were spring virgins (they had not mated that spring, but may have stored sperm from fall matings); thus sperm stored presumably from fall matings is important in this system. As the interval between matings increased P₁ increased at the expense of P[subscript ss]. As the second male to mate's copulation duration increased, P₁ also increased at the expense of P₂. This last result may indicate female influence over sperm transfer during coerced matings. Copulatory plugs (CPs) are found in many taxa, but the functional significance is debated. Male garter snakes produce a gelatinous copulatory plug during mating that occludes the opening of the female reproductive tract for approximately two days. In chapter three, "Not just a chastity belt: the role of mating plugs in red-sided garter snakes revisited", we experimentally tested the role of the CPs. In snakes, sperm are produced in the testes and delivered through the ductus deferens, and the copulatory plug is thought to be produced by the sexual segment of the kidney and conveyed through the ureter. We manipulated the delivery of the two fluids separately by ligating the ducts. We confirmed that the CP is not formed in ureter-ligated males and that sperm leaks out immediately after copulation. The CP is analogous to a spermatophore. The protein matrix contains most of the sperm which are liberated as the plug dissolves within the female's vaginal pouch. One of the fundamental principles in sperm competition is that increased sperm numbers increase the odds of winning in competitions for fertilization success and males will adjust their ejaculate relative to competition and the quality of his mate. In chapter four, "Sperm depleted males and the unfortunate females who mate with them", we detect significant among-male variation in the number of sperm ejaculated, and that male mate-order reduces sperm numbers. Male sperm numbers drop significantly from one mating to the next, and this has implications for sperm competiveness, as Thamnophis sirtalis exhibits a disassociated reproductive tactic, in that sperm stores are produced outside the breeding season, and thus cannot be replenished after mating. Interestingly, however, the on average the mobility of the sperm increased for a male's second mating. Therefore, increased sperm quality may compensate for reduced numbers in a competitive context. Further, females increase their remating rate when mating with males that are unable to deliver sperm. In chapter five, "Sexual conflict during mating in red-sided garter snakes as evidenced by genital manipulation", we revisited the CP in the context of sexual conflict. Sex-differences in optimal copulation duration can be a source of conflict, as increased copulation duration may be advantageous for males as it delays female remating. Males of many species actively guard females to prevent them from remating, and in some cases males produce copulatory plugs to prevent remating. If precopulatory choice is limited at the time of her first mating, conflict may be especially onerous to a female. The size of the plug is influenced by the copulation duration. We experimentally tested the contribution of male and female control over copulation duration. We ablated the largest basal spine on the male's hemipene and found a reduction in copulation duration and an increase in the variation of plug mass. Further, we anesthetized the female's cloaca and found copulation duration increased, which suggests that males benefit from increased copulation duration while females actively try to reduce copulation duration. Therefore, sexual conflict is manifest in divergent copulation duration optima for males and females. / Graduation date: 2013
18

Geology and Origin of the Breccias in the Morenci-Metcalf District, Greenlee County, Arizona

Bennett, Kenneth Carlton January 1975 (has links)
Rocks of the Morenci-Metcalf district consist of Precambrian metaquartzite-schist, granodiorite, and granite overlain by Paleozoic and Mesozoic sediments. Intrusion of igneous rocks, emplacement of breccia masses, and associated hydrothermal activity occurred in Laramide time. Breccias of the district are associated with the youngest sialic intrusive complex. This sequence includes intrusion of the Older Granite Porphyry stock, main stage district hydrothermal alteration, quartz veining, breccia formation, main stage district hydrothermal mineralization, and intrusion of the Younger Granite Porphyry plug. Breccia formation in the Morenci-Metcalf district is similar to breccia descriptions reported in the literature for other porphyry copper deposits. Three breccia types, of separate and distinct origins, are herein described as the Morenci, Metcalf and King, and Candelaria Breccias. The Morenci Breccia is an intrusion breccia that has formed along a pre-existing structural feature during the ascent and emplacement of the Older Granite Porphyry stock. It exhibits an oblate lenticular shape with angular to subrounded fragments in a matrix of quartz, K-feldspar, biotite, and minor rock flour. The Metcalf-King Breccias and numerous smaller breccia masses are the remnants of an original Older Granite Porphyry mantle above the ascending Younger Granite Porphyry complex. The breccia masses occur as large 'xenoliths' floating within the Younger Granite Porphyry plug and were formed by surging and collapse during emplacement of this intrusive. Fragments in the Metcalf and King Breccias grade from angular in the central core to rounded at the contacts and occur in a matrix of sericite, K- feldspar, quartz, and rock flour. The Candelaria Breccia is an explosion pipe and is the largest continuous breccia mass in the district. It is oval with an inverted cone appearance consisting of angular to subangular equidimensional fragments in a matrix of sericite, quartz, specularite, and rock flour. All the breccia masses occur within and subsequent to the district phyllic (quartz-sericite-pyrite) alteration zone. Main stage district copper mineralization postdates emplacement of the Older Granite Porphyry stock and breccia formation, and is prior to the intrusion of the Younger Granite Porphyry plug. Late stage quartz-sericite-pyrite-chalcopyrite veinlets occur in the Metcalf-King Breccia group. Field mapping and laboratory studies indicate that the Older Granite Porphyry stock appears to have been the main district mineralizer.
19

Osteochondrale Transplantation am Kniegelenk – Schicksal der Entnahmedefekte nach Implantation von TruFit®-Zylindern bei großen Knorpeldefekten / Osteochondral transplantation in the knee joint - fate of donor sites after implantation of TruFit Plugs

Quarch, Verena Mafalda Antonia 01 July 2014 (has links)
Aufgrund einer möglichen Entnahmemorbidität sind Knorpelschäden am Knie von mehr als 3 cm ² Größe bei der autologen osteochondralen Transplantation (OCT) als kritisch zu betrachten. In dieser Studie wurde untersucht, ob die Entnahmemorbidität beo großen Knorpelschädendurch durch den Einsatz von OBI TruFit Plugs reduziert werden kann. Wir führten die autologe osteochondrale Transplantation bei insgesamt 37 Patienten durch und die Knorpel-Knochen-Zylinder wurden aus dem dorsalen medialen femoralen Kondylus entfernt. Die Defekte an der Entnahmestelle wurde bei 21 Patienten (mit einer durchschnittlichen Defektgröße von 5,5 cm²) mit künstlichen TruFit Plugs gefüllt, bei 16 Patienten (mit einer durchschnittlichen Defektgröße von 4,6 cm2) wurden die Defekte der Entnahmestellen unbehandelt gelassen. Im Durchschnitt wurden die Patienten in der Studiengruppe (mit TruFit Plugs behandelt) nach 12,8 (± 1,8) Monaten postoperativ und nach 25,2 (± 1,8) Monate erneut nachuntersucht; in der Kontrollgruppe (unbehandelt gelassene Entnahmestellen) wurden dieNachuntersuchungen nach 13,8 (± 4,3) Monate durchgeführt sowie nach 58,9 (± 4,0) Monaten. In der Studiengruppe verbesserten sich die Ergebnisse von Tegner-Score, WOMAC, VAS und Knee-Society-Score von präoperativ 3,2 (± 0,8), 60,9 (± 41,6), 133,6 (± 27,1) und 4,8 (± 2,3) auf 3,9 (± 0,6), 35,5 ( ± 27,1), 177,8 (± 16,6) und 3,3 (± 2,9) Punkten zum Zeitpunkt des zweiten Follow-up; die Kontrollgruppe zeigte präoperativ Score-Ergebnisse von 2,8 (± 0,9), 73,3 (± 50,2), 123,8 (± 41,5 ) und 5,3 (± 2,7) Punkten und verbesserte diese auf 3,6 (± 0,8), 41,4 (± 28,8), 179,3 (± 17,5) und 3,1 (± 2,0) Punkte zum Zeitpunkt des zweiten Follow-up. Je kleiner der anfängliche Knorpeldefekt in der Studiengruppe war, desto besser wurden die WOMAC Score-Werte (p < 0,05). Die MRI-Auswertung führte zu einer Verbesserung der Gesamtpunktzahl im modifizierten Henderson in der Studiengruppe an den Entnahmestellen von 19,2 (± 3,3) auf 13,7 (± 2,1) Punkte und an der Empfängerstelle von 12,2 (± 2,4) auf 12 (± 1,7) Punkte (p <0,001), die Score-Werte für die die Kontrollgruppe zeigte an den Entnahmestellen 18,3 (± 3,4) und 15,4 (± 4,4) Punkte sowie für die Empfängerstellen 11,1 (± 1,8) und 13,7 (± 2,6) Punkte (p = 0,0015). OCT ist eine wirksame Therapie auch bei großen Knorpeldefekten> 3 cm ². Die Rückenflosse medialen Femurkondylus ist ein geeigneter Spender Website, zeigt eine niedrige Entnahmemorbidität und eine hohe Regenerationsfähigkeit. Durch das Ausfüllen der Mängel mit TruFit Implantate keine klinischen Verbesserungen gefunden als Entnahmemorbidität bereits niedrig ist sowieso. Allerdings nahm die Regeneration von Defekten mit TruFit Implantate gefüllt mehr als 2 Jahren.

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