No description available.

Hyaline cartilage is a highly specialized tissue, which plays an important role in the articulating joints of an individual. It provides the joints with a nearly frictionless, impact resisting surface to protect the ends of the articulating bones. Articular cartilage has a poor self-repair capacity and, therefore, it rarely heals back to normal after an injury. Overweight, injuries, overloading and genetic factors may initiate a degenerative disease of the joint called osteoarthritis. Osteoarthiritis is a major global public health issue. Currently, the most used treatment for large articular cartilage defects is joint replacement surgery. However, possibilities to replace this highly invasive operation with strategies based on tissue engineering are currently investigated. The idea of the tissue engineering is to optimize the use of the cells, biomaterials and culture conditions to regenerate a new functional tissue for the defect site. The goal of this thesis was to manufacture cartilage tissue in cell culture conditions in vitro. Bovine primary chondrocytes isolated from the femoral condyles were used in all the experiments for neocartilage production. The samples were collected for histology, gene expression level quantifications, and analyses of proteoglycan (PG) content and quality. The histological sections were stained for type II collagen and PGs, the quantitative RT-PCR was used to observe the relative expressions of aggrecan, Sox9, procollagen α2(I) and procollagen α1(II) genes. The PGs were quantified using a spectrophotometric method, and agarose gel electrophoresis was used to separate the PGs according to their size. In the two first studies, we optimized the culture conditions of in vitro scaffold-free culture technique to produce the native-type hyaline cartilage of a good quality. We found out that high glucose concentration and hypertonic medium at 20% oxygen tension promoted the best hyaline-like neocartilage tissue production. Glucosamine sulfate supplementation, low oxygen tension, 5 mM glucose concentration and a transient TGF-β3 supplementation were not beneficial for the neocartilage formation in the scaffold-free cell culture system. In the third study, we used these newly defined, optimized culture conditions to produce the neocartilage tissues in the HyStem™ and the HydroMatrix™ scaffold materials and we compared these tissues to the ones grown as scaffold-free control cultures. We noticed that there was no difference between the controls and the scaffolds, and occasionally the scaffold-free controls had produced better quality cartilage than the ones with the scaffolds. Overall, the neocartilage tissues were of good hyaline-like quality in the third study. Their extracellular matrix contents were close to the native cartilage, although the neotissues lacked the zonal organization typical to the normal articular cartilage. The tissues had the right components, but their ultrastructure differed from the native cartilage. In conclusion, we were able to optimize our in vitro neocartilage culture method further, and discovered a good combination of the culture conditions to produce hyaline-like cartilage of good quality. Surprisingly, the scaffold materials were not beneficial for the cartilage formation. / Lasi- eli hyaliinirusto on pitkälle erikoistunutta kudosta, jolla on erittäin tärkeä rooli yksilön nivelten toiminnassa. Kudos suojaa ruston alapuolista luuta muodostamalla lähes kitkattoman ja joustavan liikkumista helpottavan pinnan. Lasiruston oma uusiutumiskyky on hyvin heikko, ja näin ollen kudos vain harvoin paranee alkuperäisen kaltaiseksi vaurion jälkeen. Ylipaino, vammat, liiallinen kuormitus tai geneettiset tekijät voivat käynnistää rustokudoksen rappeutumisen. Tätä tilaa kutsutaan nivelrikoksi. Nivelrikko on valtava kansanterveydellinen ongelma. Keinonivelleikkaus on nykyisellään ainoa hoitokeino pinta-alaltaan laajojen nivelruston vaurioiden hoitoon. Vaihtoehtoja tämän suuren ja invasiivisen kirurgisen operaation korvaamiseksi tutkitaan kuitenkin koko ajan ympäri maailmaa. Kudosteknologian ajatuksena on optimoida solujen, biomateriaalien ja erilaisten kasvatusolosuhteiden käyttö uuden, alkuperäisen kaltaisen toiminnallisen kudoksen luomiseksi vauriokohtaan. Väitöskirjan kaikissa kolmessa osatutkimuksessa uudisrustokudoksia tuotettiin käyttäen naudan polven rustosta eristettyjä primäärisiä rustosoluja. Näytteet kerättiin histologisia analyysejä, geenin ilmentymistutkimuksia ja proteoglykaanisisällön ja -jakauman (PG) analyyseja varten. Histologisista leikkeistä värjättiin tyypin II kollageeni ja PG:t, ja kvantitatiivista RT-PCR -menetelmää käytettiin aggrekaani-, Sox9-, prokollageeni α2(I)- ja prokollageeni α1(II)-geenien suhteellisten ilmentymistasojen määrittämiseen. Proteoglykaanisisältö analysoitiin käyttäen spektrofotometristä menetelmää, ja PG:t eroteltiin kokonsa perusteella agaroosigeelielektroforeesia käyttäen. Kahdessa ensimmäisessä osatutkimuksessa optimoitiin tukirakenteetta kasvattujen uudisrustojen kasvatusolosuhteita natiivin kaltaisen lasiruston tuottamiseksi. Havaitsimme, että korkea glukoosipitoisuus ja hypertoninen elatusaine yhdistettynä 20 % happiosapaineeseen tuotti parhaimman laatuista uudisrustokudosta tutkituista yhdistelmistä. Glukosamiinisulfaatin lisäys, matala happiosapaine, 5 mM glukoosi konsentraatio tai TGF-β3:n lisääminen alkuvaiheessa eivät edesauttaneet uudisrustokudosten muodostumisessa. Kolmannessa osatutkimuksessa otettiin käyttöön uudet, hyväksi havaitut kasvatusolosuhteet yhdistettynä HyStem™ and HydroMatrix™ -tukimateriaaleihin, ja niitä verrattiin tukirakenteettomaan kasvatusmenetelmään. Tutkimuksessa havaittiin, ettei tukirakenteettoman kontrollin tai tukimateriaalien välillä ollut mitään eroa, ja että kontrollikasvatukset tuottivat ajoittain jopa parempaa rustoa kuin tukimateriaalein kasvatetut. Kaiken kaikkiaan kaikki tuotetut uudiskudokset muistuttivat laadullisesti lasiruston kaltaista kudosta. Molekyylisisältö lähenteli natiivia rustoa, vaikkakin uudiskudoksista puuttui normaalille nivelrustolle tyypillinen vyöhykkeinen järjestäytyminen. Kudoksissa oli parhaimmillaan oikea määrä oikeita komponentteja, mutta ne eivät vain olleet järjestäytyneet oikealla tavalla. Onnistuimme optimoimaan uudisrustokudosten kasvatusmenetelmäämme. Löysimme hyvän kasvatusolosuhteiden yhdistelmän, jonka avulla kykenimme tuottamaan lasiruston kaltaista uudisrustokudosta. Hivenen yllättäenkin, tukimateriaalit eivät olleet avuksi tutkimuksessamme uudisrustokudoksia muodostettaessa.

Le contrôle de la morphologie de la couche active en optoélectronique organique représente un objectif majeur du fait de son impact sur la stabilité et les performances des dispositifs. En particulier, le degré d'autoorganisation d'un mélange de deux composés à caractère donneur (D) et accepteur (A) d’électrons, ainsi que leurs orientations sont déterminants pour obtenir à la fois un de transfert de charges efficace et des chemins de percolation continus jusqu'aux électrodes. Durant ce travail de thèse, nous avons synthétisé plusieurs séries de co-oligomères à blocs donneur-accepteur capables de s’auto-organiser pour former des lamelles alternées D/A à longue distance. Les co-oligomères présentent une architecture moléculaire de type diade (DA) ou triade (DAD ou ADA), et sont constitués d’une longueur de bloc D variable. Les molécules sont toutes composées d'un bloc A à base de perylène diimide et d'un bloc D contenant les motifs thiophène, fluorène et benzothiadiazole. Une attention particulière a été portée sur l'étude des propriétés optiques, électrochimiques, photophysiques, structurales ou encore opto-électroniques de nos matériaux. En particulier, nous nous avons montré que l’organisation lamellaire était très fortement dépendante de l’architecture moléculaire, puisque seuls les systèmes AD et ADA conduisent à une structuration à longue distance. Par ailleurs, en ajustant la densité électronique au sein du bloc D, nous avons montré qu’il était possible de contrôler à la fois le temps de formation et la durée de vie des états à transfert de charges. Enfin,les premiers résultats de caractérisation du transport de charges et des propriétés photovoltaïques démontrent l’intérêt de ces matériaux dans la réalisation de dispositifs photovoltaïques organiques mono-composants. / In the field of organic opto-electronics, the good control of the active layer morphology in devices represents a major objective to improve the stability and the photovoltaic performances. Especially when blends of selforganizing electron donor (D) and acceptor (A) moieties are combined, their mutual orientation and the degree of supramolecular ordering are determinant in controlling the fundamental energy, the electron transfer processes and the existence of continuous percolation pathways for charge carriers. In this work, we have designed and synthesized different series of donor-acceptor block co-oligomers able toself-assemble in a lamellar structure at very long range. The co-oligomers are made of a dyad (AD) or triad (DAD, or ADA) molecular architecture, and have a variable length of the D block. The A block is constituted of a perylene diimide unit, and the D block of benzothiadiazole, thiophene and fluorene segments. A particular attention was paid on the studies of optical, electrochemical, photophysical, structural and opto-electronical properties. In particular, we showed that the lamellar organization was strongly dependent on the molecular architecture, since only the AD and ADA systems lead to long-range organization. Moreover, by tuning the electronic density along the D block, it has been possible to control both the formation and lifetime of the charge transfer states. Finally, the first results on charge transport and photovoltaic properties demonstrate the high interest of these materials for the elaboration of single component organic photovoltaic devices.

The intervertebral disc (IVD), situated between adjoining vertebrae, consists of the gelatinous nucleus pulposus (NP) in the centre surrounded by the tougher annulus fibrosus (AF). Its main roles are to distribute loads and to act as joints. With aging, degenerative disc disease (DDD) occurs due to an imbalance in anabolic and catabolic events in the IVD, which results in a loss of function. Lower back pain (LBP) affects 84% of people at some point in their lifetime and is strongly associated with DDD. Current LBP treatments have limited long term efficacy and are symptomatic rather than curative. Cell-based therapies are regarded to hold great potential for the treatment of DDD as it has been hypothesised that they could regenerate the damaged tissue and alleviate LBP. A number of natural and synthetic biomaterials have been investigated as NP tissue engineering scaffolds with varying results. In this study, a self assembling peptide hydrogel (SAPH) was investigated for its potential as a cell carrier and/or scaffold for NP tissue engineering. SAPHs display the advantages of natural polymer hydrogels such as biocompatibility and biodegradability whilst combining the advantages of synthetic materials such as controlled structural and mechanical propertiesCharacterisation determined that the SAPH nanofibrous architecture had features that were of similar scale to extracellular matrix (ECM) components of the human NP. The mechanical properties of the SAPH could be optimised to closely match the native tissue. The system could shear thin and self-heal making the system ideally suited to delivery via minimally invasive procedure. The three dimensional (3D) culture of bovine NP cells (bNPCs) in the SAPH demonstrated that the NP phenotype could be restored after de-differentiation during monolayer culture. Gene expression results demonstrated that ‘traditional’ and ‘novel’ NP markers were highly expressed throughout in vitro culture. Cell viability was high, cell population remained stable and bNPCs adopted the characteristic rounded morphology of native NPCs. Finally, type II collagen and aggrecan, the main ECM components of the NP, were deposited with increasing production over culture period. Growth differentiation factor 6 (GDF-6) has been identified as the most promising current growth factor for inducing discogenic differentiation from human bone marrow mesenchymal stem cell (h-BMMSCs). After samples were stimulated with GDF-6, gene expression results confirmed that a NP-like phenotype could be induced with high expression of ‘traditional’ and ‘novel’ NP markers. Cell viability was high, cell population remained stable and NP associated ECM components were deposited with cells displaying a rounded morphology. Interestingly, when h-BMMSCs were cultured without GDF-6, it was strongly suggested that spontaneous discogenic differentiation occurred after culture in the SAPHs as ‘traditional’ and ‘novel’ NP markers were highly expressed, morphology was comparable to native NPCs and type II collagen and aggrecan were deposited extracellularly. If these findings were accurate then this is the first study to demonstrate that a NP-like phenotype could be induced from MSCs without use of an exogenous growth factor or a discogenic bioactive motif. Despite exciting and novel results, further work is required to confirm the potential of SAPHs for NP tissue engineering scaffolds.

Mechanical assembly is an important step during product realization, which is an integrative process that brings together the parts of the assembly, the people performing the assembly and the various technologies that are involved. Assembly planning involves deciding on the assembly sequence, the tooling and the processes to be used. Assembly planning should enable the actual assembly process to be as effective as possible.Assembly plans may have to be revised due to issues arising during assembly. Many of these revisions can be avoided at the planning stage if assembly planners have prior knowledge of these issues and how to resolve them. General guidelines to make assembly easier (e.g. Design for Assembly) are usually suited for mass-manufactured assemblies and are applied where similar issues are faced regularly. However, for very specific issues that are unique to some domains only, such as aircraft assembly, only expert knowledge in that domain can identify and resolve the issues. Assembly experts are the sources of knowledge for identifying and resolving these issues. If assembly planners could receive assembly experts’ advice about the potential issues and resolutions that are likely to occur in a given assembly situation, they could use this advice to revise the assembly plan in order to avoid these issues. This link between assembly experts and planners can be provided using knowledge based systems. Knowledge-based systems contain a knowledge base to store experts’ knowledge, and an inference engine that derives certain conclusions using this knowledge. However, knowledge acquisition for such systems is a difficult process with substantial resistance to being automated. Methods reported in literature propose various ways of addressing the problem of automating knowledge acquisition. However, there are many limitations to these methods, which have been the motivations for the research work reported in this thesis. This thesis proposes a dialog-like method of questioning an expert to automatically acquire knowledge from assembly experts. The questions are asked in the context of an assembly situation shown to them. During the interviews, the knowledge required for diagnosing potential issues and resolutions are identified. The experts were shown a situation, and asked to identify issues and suggest solutions. The above knowledge is translated into the rules for a knowledge based system. This knowledge based system can then be used to advise assembly planners about potential issues and solutions in an assembly situation. After a manual verification, the questioning procedure has been implemented on computer as a software named EXpert Knowledge Acquisition and Validation (ExKAV). A preliminary evaluation of ExKAV has been carried out, in which assembly experts interacted with the tool using the researcher as an intermediary. The results of these sessions have been discussed in the thesis and assessed against the original research objectives. The current limitations of the procedure and its implementation have been highlighted, and potential directions for improving the knowledge acquisition process are discussed.

Ce travail de thèse propose de réaliser un nanofil électrique auto-assemblé constitué de protéines. L'unité de base de ce nanofil est une protéine chimère comprenant un domaine capable de former des fibres amyloïdes (Het-s 218-289) et un domaine capable d'effectuer des transferts d'électrons (une rubrédoxine). Le premier domaine permet la réalisation d'une fibre par auto-assemblage tandis que le deuxième est exposé à la surface de cette structure. Les caractéristiques redox du domaine exposé permettent aux électrons de se déplacer d'un bout à l'autre de la fibre par sauts successifs. Un tel nanofil a été créé et caractérisé par différentes techniques biophysiques. Ensuite, la preuve de la conduction des nanofils a été apportée sur des ensembles d'objets, de manière indirecte par électrochimie, et de manière directe par des mesures tension/courant. Ces travaux ouvrent la voie à la réalisation d'objets biocompatibles, biodégradables, possédant des propriétés électroniques exploitables dans des dispositifs technologiques. / The research described in this thesis aims at creating a self-assembled nanowire only made of proteins. The building block of this wire is a chimeric protein that comprises an amyloid fibril forming domain (Het-s 218-289) and an electron transfer domain (rubredoxin). The first one self-assembles in amyloid fibrils which display the second at their surface. Redox characteristics of the exposed domain allow electrons to move from one extremity of the fibril to the other by successive jumps. Such a nanowire has been created and characterized by various biophysical experiments. Then, the conductivity of the nanowires has been demonstrated on sets of wires by electrochemistry and by direct current measurements. These experiments pave the way for future design of biocompatible and biodegradable objects that possess usable electronic properties.

Thesis deals with problems about areas of a non-assembling diagnostics namely resonant adhesive tester according to an EUSAMA methodology. Result of the methodology is a technical condition examination of dampers. However with regard to testing of whole suspension and damping vehicle system are results distorted by influence of testing conditons and another vehical components. Goal of thesis is analysis limits of practical use resonant adhesive tester for a quality checking of mount wheels damping. Problems are solved by a virtual simulation in a program Adams/View where is created a real model of vehical axle of Skoda Roomster TDI 1.4. In the model is consequently simulated possible functional characteristics and abrasions of single components which influence the methodology. Virtual model will be using for research activity of Institute of machine and industrial design Faculty of mechanical ingeneering Brno University of technology.

This thesis introduces issues of passenger car side-door hinges. Practical part of this thesis deals with modifying the current low-cost side-door hinge for Edscha Automotive Kamenice s.r.o. First, material was chosen to decrease weight while maintaining the required mechanical properties. Then follows the detail design of the hinge model, which was created in the software program Catia. Heat and surface treatments are described. Both treatments ensures the hinge's final features. To verify the strength of the hinge, tensile and sag test was simulated in Ansys. Subsequently, record from the consultation of the hinge's manufacturability in series and the hinge’s cutting plans are provided. At the end of the thesis, the assembling procedure is suggested. Final part of the thesis compares the developed low-cost hinge against two similar side door hinges.

This doctoral thesis is dedicated to the synthesis and characterization of novel functionalized hybrid structures for biomedical purposes. Systems reported in this work can be subdivided into the two main groups: natural-based materials and synthetic amphiphilic block copolymers. Both groups were studied as perspective theranostic agents for medical applications. In the first group, natural polysaccharides glycogen and mannan were selected as starting materials for preparation of novel nanoconjugates that possess ability for multimodal detection in vivo. Because grafting of natural macromolecules with synthetic polymers generally slows down the biodegradation rate, both polysaccharides were modified in two different ways to form nanoprobes with or without poly(2-methyl-2-oxazoline)s chains. The prepared nanoconjugates were functionalized with N-hydroxysuccinimide-activated fluorescence and magnetic resonance imaging labels. The resulting materials were tested both in vitro and in vivo and were shown to be completely biocompatible, biodegradable and exhibit some extra benefits in terms of their practical usage in biomedicine. Glycogen was functionalized with allyl and propargyl groups with following freeze-drying from aqueous solutions to form nano- and microfibrous materials. The presence of both...

В современном машиностроении трудоемкость сборочных работ составляет 30-40% и более от общей трудоемкости изготовления изделия. В условиях, когда большинство предприятий использует устаревшие технологические процессы. Перед предприятиями возникла проблема модернизации производства по современным требованиям. Для этого требуется изменение технологии изготовления деталей, плановых объемных и календарных показателей. Актуальность темы обусловлена необходимостью России вступить в пятый и шестой технологический уклад. Цели данной научно-исследовательской работы: оптимизация технологического процесса, выявление узких мест и их нивелирование, устранение простоев и недостатков существующей схемы модели, возможное увеличение производительности. Областью применения может являться любое предприятие. данные аналитические методы возможно применять на всех машиностроительных предприятиях, но в данный момент их применяют только передовые компании. / In modern mechanical engineering, the labor intensity of assembly work is 30-40% or more of the total labor intensity of the product. In a situation where most enterprises use outdated technological processes. Enterprises faced the problem of modernizing production according to modern requirements. To do this, you need to change the manufacturing technology of parts, planned volume and calendar figures. The objectives of this research work are: Refinement of the technological process designed in the first section; - Identification of bottlenecks and their levelling; Eliminate downtime and deficiencies of the existing model layout; - Possible productivity boosting. An application field can be every enterprise. These analytical methods can be used in all engineering enterprises, but at the moment they are used only by advanced companies.)