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Mechanical and neural factors have been suggested to limit finger independence. Fingers producing involuntary movement or force production during intended actions of another finger are considered “enslaved” to that finger. The purpose of this thesis was to quantify the contribution of passive mechanical factors to this enslaving effect, in particular, the contributions of the intertendinous connections between extensor tendons. Twenty participants (10 men, 10 women) performed Master and Slave Tasks in three wrist (30° extension, neutral, 30° flexion) and two metacarpophalangeal (MCP) (straight and 90° flexion) postures. During the Master Task, the ring finger was the intended or “master” finger. Three 10 s isometric ring finger extensions were performed at 25% of maximum voluntary contraction. Finger force and surface electromyography of the 4 extensor digitorum (ED) bellies were recorded. In the Slave Tasks, the middle and little fingers (“slave” fingers during the Master Task) each performed three 10 s isometric finger extensions at their mean activation levels during the Master Task. Hypothetical mechanical contribution (HMC) was determined for the middle and little fingers. The HMC was defined as the difference between the involuntary force (from the Master Task) and the voluntary force (from the Slave Task) relative to the involuntary force. A small proportion of the HMC values (Middle: 39%; Little: 15%) were within the expected range of 0 to 100%, suggesting that the equation developed in this study provided a limited representation of the contribution of passive intertendinous structures. Index finger forces increased with MCP flexion, suggesting the importance of juncturae tendineii in finger independence. Higher ED activity during wrist extension, than neutral or flexed postures, with straight MCP supports previous evidence in the literature. The complex phenomenon of enslaving in different wrist and MCP positions warrants further research for quantifying the mechanical contribution in finger independence. / Thesis / Master of Science in Kinesiology

An attempt to reproduce tendon sheaths using autologous venous grafts has been undertaken in Cercopithecus aethiops (Blue Vervet Monkey). Ten venous grafts were tested. Five were placed around sutured tendons in paratenon, and the remainder around tendons in sheath formation. In no instance did synovial-like sheaths form. In the latter series, the experiment was controlled, and the results obtained expressed in terms of function. The functional results of the venous ensheathed tendons were worse than those of the controlled tendons.The controlled experiment was confined to the digital sheath, an area notoriously liable to adhesion formation, and the one which offered the most critical test of operative technique.A method for the evaluation of function, following the repair of divided tendons in the experimental animal has been presented. Voluntary movement of joints in the experimental animal was obviously impossible, but the method employed in this experiment, namely, the electrical stimulation of muscles, and the photographic recording of the range of joint movement, presented no disadvantages.The experimental animal used in this study was ideal, in that anatomical studies of the hand of this species, revealed features both structurally and functionally comparable to those in man.The anatomical and physiological aspects of tendon action, the mechanics of tendon gliding, and the healing processes in divided tendons have been studied.The fate of human autologous venous grafts has been investigated.A review of previous methods employed to prevent peritendinous adhesions has been presented.

Les plantes ont la capacité à former de nouveaux organes grâce à une croissance continue assurée par une réserve de cellules souches au sein de structures spécifiques, les méristèmes. Les méristèmes floraux diffèrent des méristèmes végétatifs par leur caractère déterminé aboutissant à la production des fleurs. Le gène IMA (INHIBITOR OF MERISTEM ACTIVITY) code une protéine contenant un motif «doigt à zinc» (MIF) régulant les processus développementaux de la fleur et des ovules chez la tomate. En effet, IMA inhibe la prolifération cellulaire au cours de la terminaison florale en agissant sur l’expression du gène WUSCHEL, responsable du maintien du pool de cellules souches et contrôle le nombre de carpelles (Sicard et al., 2008). De plus, les protéines IMA et son orthologue chez Arabidopsis, MIF2, modulent la réponse à certaines phytohormones. De manière identique à la protéine MIF1 (Hu and Ma, 2006), IMA/MIF2 régule négativement la réponse aux brassinostéroïdes, à l’auxine, aux cytokinines et aux gibbérellines mais positivement la réponse à l’acide abscissique suggérant une fonction commune des protéines MIF dans les voies de réponse aux phytohormones. Un criblage d’une banque d’ADNc par la technique de double hybride a permis de révéler l’interaction entre les protéines IMA/MIF2 et une sous-unité du complexe signalosome, CSN5. De façon intéressante, les plantes mutantes csn5 d’Arabidopsis montrent de nombreuses altérations phénotypiques telles qu’un aspect buissonnant résultant de la perte de la dominance apicale, et une altération de la réponse à l’obscurité et à l’auxine. Ces phénotypes sont fortement ressemblants aux phénotypes des plantes MIF1OE d’Arabidopsis (Hu and Ma, 2006) et des plantes IMAOE de tomate (Sicard et al., 2008). Les résultats obtenus au cours de ce projet montrent que la protéine IMA inhibe la fonction du complexe signalosome grâce à son interaction avec la protéine CSN5. / Plants have the ability to form new organs as a result of indeterminate growth ensured by specific regions of pluripotent cells, called meristems. Flowers are produced by the activity of floral meristems which differ from vegetative meristems in their determinate fate. The INHIBITOR OF MERISTEM ACTIVITY (IMA) gene encoding a Mini Zinc Finger (MIF) protein from tomato (Solanum lycopersicum) regulates the processes of flower and ovule development. IMA inhibits cell proliferation during floral termination, controls the number of carpels during floral development and acts as a repressor of the meristem organizing centre gene WUSCHEL (Sicard et al., 2008). We demonstrated that IMA and its Arabidopsis ortholog MIF2 is also involved in a multiple hormonal signalling pathway, as a putative conserved feature for plant MIF proteins (Hu and Ma, 2006). Alike Arabidopsis MIF1, IMA/MIF2 regulates negatively BR, auxin, cytokinin and gibberellin signalling and positively ABA signaling. Using yeast two-hybrid screening experiments, we identified a strong protein-protein interaction between IMA and the signalosome subunit 5 (CSN5). Interestingly the csn5 mutant in Arabidopsis displays pleiotropic developmental defects such as a bushy phenotype originating from the loss of apical dominance and the alteration in sensitivity to darkness and auxin signals. These phenotypes are strikingly similar to what was described for Arabidopsis MIF1 (Hu and Ma, 2006) and tomato IMA overexpressors plants (Sicard et al., 2008), respectively. Taken together our data strongly suggest that IMA may act as an inhibitor of CSN function through its physical interaction with SlCSN5. The observed converse effects of IMA/MIF2 overexpression or deregulation on plant development and the abundance of developmental marker genes further support the notion of a CSN inhibitory control, since the COP9 signalosome through the specific deneddylation activity of the CSN5 subunit regulates plant hormone signalling.

Master of Science / Department of Mechanical and Nuclear Engineering / Steve Eckels / A new three dimensional transient human finger model was developed to predict the risk of frostbite in humans at different environmental conditions. The shape of the finger model was similar to that of a real human finger. Finite Element Techniques were used to build the finger model. Smith’s Model (1991) energy balance equations were used to calculate the temperatures in the current finger model. The current 3D finger model was validated against the experimental data of Wilson (1976) and Santee (1990). The model agreed well with the Wilson experiments and with the cold test in Santee experiments. The comparison indicates that the current finger model can be used to adequately predict the human finger responses in different environments. The current finger model was then tested in temperatures of 0, -10, -20, -25 and -30 oC and with different airspeeds 0, 3 and 6.8 m/s to assess the risk of frostbite in humans. Three resistances 0, 0.4 and 0.8 clo were used on the finger model to obtain responses in different environmental conditions. From the experimental results, an expression for safe glove resistance required to prevent frostbite in known temperatures was calculated. Also, the temperatures up to which a glove with known thermal resistance value can protect a human finger from frostbite was also computed.

Although we are surrounded by hundreds of surfaces we can still distinguish them from each other simply by touch. The tactile information, interpreted by our brain and given by our fingers, is precise, but to put words to the sensation is very difficult — is it smooth, sticky or harsh? We do not only perceive surfaces differently, we also describe them in our own way. Luckily the forces and deformations that the skin are exposed to when sliding over a surface is ruled by laws of nature. This thesis investigates the contact between finger and surface and how it is affected by, for example, material properties, surface texturing or changes in climate. By measuring contact area, friction coefficient, and adhesion, using different materials and under different conditions, conclusions could be drawn. Also, a model for the contact between a finger and a sinus­oidal surface was developed, which could be used to estimate contact area, deformation and resulting friction coefficient. Results showed how differences in for example material, surface topography and environ­ment affect the interaction between finger and surface, and what consequences it has. If the objective is to change the feel of a surface or to alter the grip, this thesis could work as a support. Paper A investigates the area and friction between finger and glass surface under different conditions. Paper B presents a model for the contact area and deformation for a finger in contact with a sinusoidal surface. Paper C is a validation of the contact area model. Here it was used on new surfaces and compared with new finger friction measurements. Paper D mainly examines whether the adhesion or stickiness of different surfaces is distinguishable by a test panel and how this affects the perceived pleasantness of the surface. Paper E relates to the adhesion and friction for a bioskin probe and skin. Tests were made to evaluate how an artificial probe can be used to evaluate the tactile properties of a surface. / Även om vi omges av hundratals olika ytor kan vi fortfarande skilja dem åt med hjälp av känseln. Den taktila informationen från fingertopparna som tolkas av hjärnan är precis, men att sätta ord på hur ytan känns är väldigt svårt. Len, sträv eller grov? Vi upplever inte bara ytorna olika utan beskriver dem också på olika sätt. Krafterna och deformationerna som huden utsätts för när den glider över en yta styrs dock av naturlagar. Denna avhandling utreder kontakten mellan fingertopp och yta och hur den påverkas av exempelvis materialval, ytstruktur eller förändringar i klimat. Genom mäta kontaktarea, friktionskoefficient och adhesion för olika material i varierande omgivning kunde slutsatser dras. En modell för kontakten mellan fingertopp och sinusformad yta togs fram vilken kunde användas till att uppskatta kontaktarea, deformation och resulterande friktionskoefficient. Resultaten visade hur skillnader i exempelvis material, yttopografi och omgivning påverkar kontakten mellan finger och yta och vilka kon­sekvenser detta får. Om målet är att förändra känslan eller friktionen för en yta kan denna avhandling fungera som stöd. Artikel A undersöker kontakten och friktionen mellan fingertopp och glasyta för olika förhållanden. Artikel B presenterar en modell för arean och deformationen som sker för fingertopp och sinusformad yta i kontakt. Artikel C är en validering av modellen. Här användes den för nya ytor och jämfördes med nya mätningar av fingerfriktion. Artikel D undersöker i huvudsak huruvida en testpanel kan särskilja adhesionen för olika ytor och hur detta påverkar hur den känns. Artikel E arbetar vidare med adhesion och undersöker och hur en testkropp av artificiell hud kan användas för adhesionsmätningar av en yta. Detta för att med relativt enkla mätningar kunna uppskatta ytans taktila egenskaper. / <p>QC 20160504</p>

published_or_final_version / abstract / Orthopaedics and Traumatology / Doctoral / Doctor of Philosophy

The issue on variability of mechanical properties within wood has found to be increasingly prominent in recent years. On the other hand, it is known that uniformity of wood properties is essential in quality control in the timber manufacturing such as manufacturing of Glued Laminated (Glulam) timber. The AS/NZS 1328 P2 specified that the overall mechanical properties of Glulam timber can be estimated based on the MOE of the finger jointed laminates and the arrangement of the corresponding laminates. In relating to the above standard, optimisation in the arrangement of shooks’ location along the finger jointed laminate will enable determination of the overall MOE of laminates, as well as optimise the utilisation of feedstocks. In this study, a deterministic model was developed in relating the local shook’s modulus of elasticity (MOE) with the overall MOE of the corresponding finger jointed timber based on the principle of the Moment of Curvature. The projected overall MOE is calculated as a function of lengths and MOEs of individual shooks in the finger joint timber. The effect of shooks’ location can also be determined from the model. Numerical derivation of the model was addressed and the analyses of the relationships between the local shook MOEs, the overall MOE, and bending strength (MOR) were assessed. Experimental results showed that the model can effectively predicts the overall MOE, particularly on shook combinations with random and large standard deviations in shook MOEs. The errors of the predictive model were ranged from -8.17% to +0.81%. Results from the assessment on the relationships between the overall MOE and bending MOR indicated that wood failure in the combinations of small standard deviations shook MOEs was most likely to occur at the weakest point, however, wood failures may not necessarily occur in the shook with the lowest MOE in the asymmetrical MOE arrangements. This also applies to the finger jointed timber with combinations of shooks with large standard deviations for local MOEs. In addition, the relationship between dynamic MOE of shooks and the static bending overall MOE were assessed. A linear regression has been suggested for the adjusted shooks dynamic MOE at 36 mm thickness. The predictability of the model could further improve when the shook MOEs were sorted according to sawing pattern and the proposed model for quarter sawn is suggested. Lastly, economic analysis was performed based on the models available in literature and the developed model in this study. Models reported in the literature including the arithmetic mean model and model based on the shook’s minimum MOE. The results from economic analysis showed that the study’s model was most cost effective in predicting the cost of shooks based on the predicted overall finger jointed MOE using the model as compare to the arithmetic mean and the minimum shook MOE method. In conclusion, the proposed model has demonstrated to be unique, simple, effective and robust in predictive applications.