Title Promoter Affiliations Abstract "Functional anatomy and biomechanics of brachiating gibbons (Hylobatidae): an example of locomotion in complex environments." "Peter Aerts" "Royal Zoological Society of Antwerp" "Recent literature on the biomechanics of arboreal locomotion revealed that gibbons are able to brachiate with very low mechanical costs. They do this by making pendular movements, continually exchanging potential and kinetic energy to optimally conserve energy. In addition, they must minimise their collisional energy losses by ensuring that the passage between two movements happens smoothly without abrupt changes in the path of the body centre of mass. Although the animals appear to succeed in doing this in uniform, predictable experimental circumstances, this cannot provide satisfactory detail of the degree of co-ordination and control in more naturalistic complex surroundings with compliant and heterogeneously spaced branches In this PhD project we used a combination of morphological, kinematical and dynamical analyses to question whether gibbons adjust their movement patterns adequately to the mechanical complexity of support structures.The first two chapters discuss the functional anatomy of hylobatids in relation to brachiation as their primary locomotion mode. The shoulder flexors, extensors, rotator muscles, elbow flexors and wrist flexors seem shaped to contribute the most to brachiation. Particularly the elbow flexors of gibbons are more powerful compared to those of non-specialised brachiators. In addition, both elbow and wrist flexors stand out in terms of moment of force-generating capacity, compared to non-brachiating species. Siamang forelimb muscles perform at their maximum during brachiation. However, the elbow flexors may be adapted to more demanding movements, given that maximal output is reached at the stronger flexed elbow positions which are reached during brachiation in a more spatially complex setup.In chapter 3, a kinematical study of continuous contact brachiation in a simplified environment revealed four locomotory transitions that are mainly associated with speed. The results showed that regardless of the transition type, energy recovery is always relatively high and collision fraction relatively low. Chapter 4 discusses the effect of spatial heterogeneity of available support structures and brachiation speed on brachiation mechanics. Energy recovery was observed to be primarily determined by brachiation speed. Furthermore, the results indicate that collisional losses seem to be avoided during all the experimental setups used in this study. The expected effect of increasing spatial complexity, however, was not found: the energy recovery is kept high in all presented situations, except when brachiating at higher speed. Finally, chapter 5 examines the effect of a compliant support structure on brachiation. The two individuals that were studied each had a different strategy to cope with the compliant handhold. One animal consistently used continuous contact brachiation and avoided additional lowering of the body centre of mass due to spring elongation by lifting the free, swing arm and lifting the legs. The other animal avoided the compliant handhold regularly by ricocheting over the setup without grabbing the compliant handhold. However, when take-off from the previous rigid handhold was not with the right velocity or timing to ensure successful grabbing of the next rigid handhold, the compliant handhold was shortly used with a low force (and a large variance between sequences). For both strategies, the use of the compliant handhold induced a lower energy recovery an increased collision fraction. However, for both animals, the energy recovery increased and the collision fraction decreased when the body centre of mass followed the spring elongation less. Although the complexity of the environment seems to determine brachiation mechanics, the effective use of the powerful forelimb muscles can easily adjust the movements during brachiation, assuring contact with the next available support and in addition, keeping energy exchange relatively high and collisional losses relatively low, even in a complex environment." "Looking beyond the image: biomechanics & anatomy of thumb function and instability" "Evie Vereecke" "Development and Regeneration, Kulak Kortrijk Campus, Human Movement Biomechanics Research Group" "The modern human thumb can be seen as a hallmark of human evolution. The unique anatomy of the human thumb makes it possible to carefully manipulate tools, powerfully grasp objects and even throw items with precision. These apparent contradictory functions of the thumb, high mobility for manual dexterity vs. high stability during forceful grasping, imply that daily activities impose a high strain on a relative instable joint. This makes the thumb susceptible to joint disorders such as osteoarthritis. Both systemic (e.g. genetics, hormones, obesity) and mechanical factors (e.g. joint loading) are important in the development of osteoarthritis, but the precise pathomechanism remains largely unknown. In this project, we focus on the mechanical factors in the disease process and use a multidisciplinary approach to develop, refine and apply a toolset that helps to further investigate the link between structure and (dys)function of the human thumb. First of all, we developed and validated a dynamic CT protocol that allows accurate quantification of 3D bone motion using a limited radiation dose. This validated dynamic CT technique was then used to analyze thumb motion in patients with an unstable and painful trapeziometacarpal (TMC) joint. We compared the thumb base kinematics from patients before and after a dorsal ligament shortening operation. These kinematics were compared with age-and-sex-matched healthy controls. In addition, changes in contact patterns between the articular facets during the motion cycle were mapped to assess the impact of the surgery on joint mechanics. As mechanical loading of the TMC joint is largely generated by contraction of thumb muscles, we also investigated thumb muscle activations during functional tasks using fine-wire electromyography. We found subject-specific muscle recruitment patterns which remained largely unchanged between tasks. Finally we expand on the anatomy in general. By using 7T MRI, CT and detailed dissection, a 3D digital model of the forearm and hand of a single, un-embalmed, specimen was created with full quantification of the muscle architecture, bone and cartilage geometry. This multifaceted approach has led to profound insights in the relation between form and function of the human thumb, as well as in the involvement of distinct anatomical and mechanical factors in the onset and development of osteoarthritis of the thumb joint." "How does the Trapeziometacarpal joint really function ? Anatomy and Biomechanics of the thumb" "Evie Vereecke" "Development and Regeneration, Kulak Kortrijk Campus" "The basal thumb joint or trapeziometacarpal (TMC) joint is crucial for the high mobility of the thumb. Its particular configuration has been described as a saddle joint with two principal axes of motion allowing extension-flexion and abduction-adduction. In addition, the thumb can rotate around its long axis, a movement also referred to as pronation-supination. During opposition of the thumb, which is typically used to score thumb mobility and functionality (i.e. Kapandji score), flexion, adduction and pronation are combined. With its unique configuration diplaying high intrinsic mobility and limited intrinsic stability, osteoarthritis (OA) of the TMC joint is highly prevalent, making this joint the most common hand site for surgical joint reconstruction. Painful TMC OA is a highly disabling, age-related joint disorder with a large socioeconomic impact which is only expected to increase with the aging of the population. This major public health problem strengthens the need for further research in the field.The state of knowledge shows a lack of consistency, robustness and evidence for the TMC joint ligaments anatomy and function. Available anatomical studies do not agree on the identification, nomenclature and stabilizing role of the ligaments. Early publications pointed the anterior oblique ligament (AOL) as the key stabilizing structure, while the dorsoradial ligament (DRL) has been put forward as the main TMC joint stabilizer in some more recent studies. This may have an important impact on the functional outcome of the available surgical procedures that were developed on early AOL-based concepts. Another major point in thumb function is that an accurate quantification of the kinematics of the TMC joint, but also of the more proximal joint, namely the scaphotrapezial (ST) joint, remains lacking. This is largely due to the fact that the existing body of literature on healthy and OA conditions only describe the first metacarpal (MC1) kinematics with either a fixed trapezium or trapezium-based coordinate system. Despite the high value of these studies in elucidating the TMC joint kinematics, the motion of the trapezium as well as of the scaphoid remain excluded from the analyses. Furthermore, many in vitro studies have been performed in the past years to understand the contact biomechanics of the TMC joint, with a strong inconsistency when comparing their respective results. One of the main limitations of these studies is the use of highly invasive techniques, only applicable on cadaver specimens. To date, experimental studies have not yet been able to define the behaviour of the MC1 and trapezium articular surfaces during in vivo thumb motions, and the evolution of the contact biomechanics from a healthy to a diseased TMC joint. Another surprising fact is that, since over 40 years, TMC joint arthroplasty for OA has been performed using ball-and-socket implants inspired from hip implant concepts to replace a saddle-shaped joint, without any kinematical studies on the effect total joint replacement on the three-dimensional (3D) motion capability of the TMC joint.This state of knowledge raises many questions. Where is the truth on TMC joint stabilizing ligaments? What about ligament reconstructive surgeries based on an earlier contested concept? What are we, as surgeons, supposed to do with these ligaments? Which ligaments to reconstruct? How do bones and joints move during thumb motions in daily activities? What is the pressure distribution inside the TMC joint? Is a ball-and-socket implant able to restore the native thumb mobility? Why do ball-and-socket implants work successfully and why do they fail?To address all these questions, we designed several studies, starting with the basics, i.e. ligament anatomy, then focusing on in vivo kinematics and contact biomechanics of the MC1, trapezium and scaphoid. Understanding the thumb joints anatomy and function is of primordial importance in optimizing surgical procedures and treatment strategies, as well as our knowledge on OA pathogenesis." "Development of a novel total elbow arthroplasty design based on new insight into the anatomy and biomechanics of the elbow" "Alexander Van Tongel" "Department of Industrial Systems Engineering and Product Design, Department of Human Structure and Repair" "The elbow consists out of 3 joints and its movement is characterized by complex kinematics. Total elbow arthroplasty (TEA) has been introduced in the previous century for treating a destructed joint, and the amount of TEA quadrupled since 2000 in Belgium. But in contrast to the survival rate of other joint arthroplasties, the survival rate of TEA is still low. During my dissertation, I found an anatomical variation of the bony anatomy that is currently not considered in the designs and may partially declare the high complication ratio. Therefore, the aim is to better understand the elbow's anatomy and biomechanics and to develop an innovative modifiable implant based on these novel insights. First, I will quantify and parametrize the elbow joint's anatomical variance based on 200 CT cases. Second, I will develop a musculoskeletal model of the elbow based on 30 MRI scans and optical tracking. Within this model, I will simulate the forces and torques on the elbow. Next, the laxity of the elbow joint will be robotically tested on 10 cadaveric specimens. Based on these novel insights and the filed patent application, I will develop a modular elbow implant to optimize the reconstruction of the native biomechanics. This novel implant will be compared with the current available TEA within the musculoskeletal model and with the robot." "Galaxies’ Anatomy - panchromatic SED modelling of spatially resolved galaxies in the local Universe" "Maarten Baes" "Department of Physics and astronomy" "Galaxies are an amalgamation of several components (dark matter, stars, gas, and dust), constantly interacting with one another. This interaction is imprinted on the spectral energy distribution (SED) of a given galaxy. Through a detailed study of the panchromatic SED we can shed light on the astrophysical processes that regulate galaxy evolution. However, the current SED modeling approaches come with many caveats and limitations. One of the main issues is that the star-formation histories (SFH) are usually poorly modeled, with significant systematics on parameters as the stellar mass or star-formation rate as a result. Moreover, global SED fits yield parameters that can deviate systematically from more reliable spatially resolved SED fits. We propose a full SED fitting of a representative sample of resolved galaxies, based on a combination of panchromatic imaging and spectroscopic data. We will adopt a fully Bayesian SED modeling framework and an innovative spatial image reconstruction technique to generate maps of the most important physical galaxy parameters. We will use these maps to quantify the bias between global and local estimates, to characterize dust scaling relations on both local and global scales, to investigate dust heating mechanisms in galaxies of different types, and to analyze the SFH on local scales. We will compare our results to those obtained using other methods. Our results can serve as interesting and original benchmark for galaxy evolution models." "Foot inversion and eversion movements in stance and swing - some comparative-anatomical and functional morphological aspects" "Koos Jaap VAN ZWIETEN" Morphology "In the lower leg of the common opossum Didelphis marsupialis, the spatium interosseum cruris between tibia and fibula widens in stance during the power stroke, reflecting external rotations of these bones, coupled to extreme inversion of the foot, which lasts until the end of push-off. Although denied in marsupials until recently the strong ligamentum astragalocalcaneum interosseum underlines the importance of our observations. From the very onset of recovery the opossum foot shows eversion. This eversion is coupled to internal rotations of both fibula and tibia in the free leg as is also reflected by the narrowing of the spatium interosseum cruris in the opossum. The precise course of m. interosseus cruris in Didelphis ursina Shaw, suggests its possible active role in this process of repositioning before and during touchdown In man, the foot at the end of stance at push-off shows but a modest inversion which however can be exaggerated to a more extreme inversion of the foot. Then tarsal joints like Chopart's joint and sinus tarsi clearly show their joint spaces on routine radiography. Normally our ligamentum talocalcaneum interosseum restrains this widening. In normal gait, a foot landing after its recovery phase may accidentally do so in a position of inversion, risking a so-called inversion traumatism, the most common ankle sprain. Training proactively e.g. the peroneus muscles, the evertors of the foot, may prevent the incidence of such traumatisms, as suggested by a pilot-study in gymnasts. Extrapolating such methods to the disabled, e.g. in early diagnosed neuropathies, implies possibilities to train these muscles thus protecting Multiple Sclerosis patients from e.g. stumbling and falling." "Unravelling the mode of action of low-frequency electromagnetic stimulation in stroke" "Annelies BRONCKAERS" "Cardio & organ systems" "Despite the high prevalence and devastating outcome, there are only few treatment options for ischemic stroke. Our project aims to explore low-frequency electromagnetic stimulation (LF-EMS) as a new therapeutic tool for this disease. Recent data of our laboratory indicate that LF-EMS increases survival and neurological outcome in rats and gerbils subjected to severe permanent ischemic stroke. LF-EMS induced migration of endothelial cells (which align the blood vessels) and production of the important messenger molecule nitric oxide (NO) by nitric oxide synthase (NOS) in vitro. Successful repair after stroke consists of also activating other cells such as neurons, microglia and astrocytes. The aim of this project is to investigate the effect of these other cell types. In addition, we will investigate whether LF-EMS has also a beneficial effect in another type of stroke, namely hemorrraghic stroke. Insights obtained in this project will enhance our current knowledge of LF-EMS as a stroke therapy as well as aid in the clinical translation of this therapy." "Unravelling the mode of action of low-frequency electromagnetic stimulation in stroke" "Annelies BRONCKAERS" "Cardio & organ systems, Morphology, University of Santiago de Cuba" "Despite the high prevalence and devastating outcome, there are only few treatment options for ischemic stroke. Our project aims to explore low-frequency electromagnetic stimulation (LF-EMS) as a new therapeutic tool for this disease. Recent data of our laboratory indicate that LF-EMS increases survival and neurological outcome in rats and gerbils subjected to severe permanent ischemic stroke. LF-EMS induced migration of endothelial cells (which align the blood vessels) and production of the important messenger molecule nitric oxide (NO) by nitric oxide synthase (NOS) in vitro. Successful repair after stroke consists of also activating other cells such as neurons, microglia and astrocytes. The aim of this project is to investigate the effect of these other cell types. In addition, we will investigate whether LF-EMS has also a beneficial effect in another type of stroke, namely hemorrraghic stroke. Insights obtained in this project will enhance our current knowledge of LF-EMS as a stroke therapy as well as aid in the clinical translation of this therapy." "Development of organoids from human and mouse teeth as novel and powerful tools to study tooth biology and pursue regenerative therapy" "Ivo LAMBRICHTS" "Cardio & organ systems, Morphology" "Tooth loss is an important health problem worldwide. Replacing lost or missing teeth with a biological tooth, preferably generated from the patient, would be highly superior to the current standard implantation of synthetic materials. Organoids, defined as self-forming three-dimensional in vitro reconstructions of an organ, provide a powerful means to pursue this goal. The tooth organoids obtained will be scrutinized to gain more insight into molecular and cellular mechanisms of tooth (stem cell) biology and tooth disease (i.e. caries). Taken together, our project will generate an innovative tooth in vitro model that will be highly valuable for studying tooth biology and disease, and will pave the way towards prevention and towards regenerative replacement therapy." "Low-frequency electromagnetic stimulation: exploring the (sub) cellular mechanisms in ischemic stroke" "Annelies BRONCKAERS" "Cardio & organ systems, Morphology" "Despite the high prevalence and devastating outcome, there are only few treatment options for ischemic stroke. Our project aims to explore magnetic stimulation (MS) as a new therapeutic tool. Preliminary data of our laboratory indicates that MS increases survival and neurological outcome in rats and gerbils subjected to severe permanent stroke. MS induced migration of endothelial cells (which align the blood vessels) and production of the important messenger molecule nitric oxide by nitric oxide synthase (NOS) in vitro. Successful repair after stroke consists of activating the endothelial cells and simultaneously protecting neurons from ischemic damage. Our preliminary data point to NO as a key regulator of magnetic stimulation-induced protection. Elucidating the link between magnetic stimulation, NO and brain repair after ischemic stroke is the goal of this project. We study how the produced NO promotes blood flow recovery by vessel dilatation (collateralization) in vivo. In addition, we investigate the subcellular mechanisms by which magnetic stimulation activates NOS in endothelial cells and how magnetic stimulation inhibits neuronal cell death. Insights obtained in this project will enhance our current knowledge of magnetic stimulation as well as of endogenous cellular and subcellular mechanisms after stroke."