This thesis reports the efforts towards the design and synthesis of a small molecule walker that would potentially move along the track directionally by exploiting the secondary interactions between the track and the walker. This thesis also reports the synthesis and operation of a light driven molecular shuttle featuring a novel acylpyridyl hydrazone station. Chapter One describes the biological walkers which are the source of inspiration towards the synthetic walkers, characteristics of a walker, previously described small molecule walkers and recent progress on the synthesis of molecular shuttles that operate under variety of different stimuli. Chapter Two describes the design and synthetic efforts towards a molecular walker that has the potential to operate directionally along the track by exploiting secondary interactions between the walker and the track namely the hydrogen bonding interactions introduced by subtle incorporation of excellent hydrogen bond donor/acceptor squaramides. This chapter briefly mentions the hydrogen bonding capabilities of squaramides on which the directional operation relies. Optimization of critical reactions and attempted strategies for the assembly of the whole machine is described as well. Chapter Three describes the synthesis and operation of 1- and 2- station [2]-rotaxanes that operate under light irradiation. 2- station [2]-rotaxane that function as a light driven molecular shuttle presents remarkable positional fidelity with high efficacy. The bistable acyl pyridyl station is incorporated as a photo active station upon which light irradiation alters the binding affinities towards the macrocycle. Series of rotaxanes featuring different amide based stations were synthesized to determine the best non-photo active station.

Šis darbas nagrinėja moterų ėjikių ugdymo metodologiją ir ypač pasiruošimą aukšto lygio varžyboms bei Olimpinėms žaidynėms. Darbo tikslas – išnagrinėti Lietuvos ėjikių rezultatų kaitą, pasaulio ir Lietuvos rekordų pasiekimą, dalyvavimą Olimpinėse žaidynėse ir treniravimo ypatumus. Tyrimui buvo naudojami fizinio pasirengimo apskaitos dokumentai, varžybų protokolai, K. Saltanovič ir N. Aidietytės labaratorinių ir pedagoginių tyrimų medžiaga. Tikimės, kad šis darbas ir treniruočių sistemos aptarimas patarnaus kaip praktinė medžiaga jaunų ėjikių reugdymui ir tolesniam rengimui kitoms bei būsimoms Olimpinėms žaidynėms ar kitoms aukšto lygio pasaulinėms ar Europos varžyboms. / This paper is analyzing the women’s race walking training methodology and preparation particularity for high level competition and the Olympics. Paper’s purpose is to dissertate Lithunia’s female race walkers results fluctuation, setting world’s and national records, taking part in Olympics and peculiaritys of training. For the assay there were used the record documents of physical preparation, competition’s protocols, laboratorical’s and pedagogical’s exams material of K. Saltanovič and N. Aidietytė. Hopefully this assay and consideration of training system will be as practical material for preparing young female race walkers and continueing futher preparation for next and oncoming Olympics Games.

Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 4 uppsatser.

Nonequilibrium statistical physics involves the study of many-particle systems that break time reversibility|also known as detailed balance|at some scale. For states in thermal equilibrium, which must respect detailed balance, the comprehensive theory of statistical mechanics was developed to explain how their macroscopic properties arise from interactions between their microscopic constituent particles; for nonequilibrium states no such theory exists. The study of active matter, made up of particles that individually transduce free energy to produce systematic movement, provides a paradigm in which to develop an understanding of nonequilibrium behaviours. In this thesis, we are interested in particular in the microscopic interactions that generate the clustering of active particles that has been widely observed in simulations, and may have biological relevance to the formation of bacterial assemblages known as biofilms, which are an important source of human infection. The focus of this thesis is a microscopic lattice-based model of two random walkers interacting under mutual exclusion and undergoing the run-and-tumble dynamics that characterise the motion of certain species of bacteria, notably Escherichia coli. I apply perturbative and exact analytic approaches from statistical physics to three variants of the model in order to find the probability distributions of their nonequilibrium steady states and elucidate the emergent interactions that manifest. I first apply a generating function approach to the model on a one-dimensional periodic lattice where the particles perform straight line runs randomly interspersed by instantaneous velocity reversals or tumbles, and find an exact solution to the stationary probability distribution. The distribution can be interpreted as an effective non-equilibrium pair potential that leads to a finite-range attraction in addition to jamming between the random walkers. The finite-range attraction collapses to a delta function in the limit of continuous space and time, but the combination of this jamming and attraction is suffciently strong that even in this continuum limit the particles spend a finite fraction of time next to each other. Thus, although the particles only interact directly through repulsive hard-core exclusion, the activity of the particles causes the emergence of attractive interactions, which do not arise between passive particles with repulsive interactions and dynamics respecting detailed balance. I then relax the unphysical assumption of instantaneous tumbling and extend the interacting run-and-tumble model to incorporate a finite tumbling duration, where a tumbling particle remains stationary on its site. Here the exact solution for the nonequilibrium stationary state is derived using a generalisation of the previous generating function approach. This steady state is characterised by two lengthscales, one arising from the jamming of approaching particles, familiar from the instant tumbling model, and the other from one particle moving when the other is tumbling. The first of these lengthscales vanishes in a scaling limit where continuum dynamics is recovered. However, the second, entirely new, lengthscale remains finite. These results show that the feature of a finite tumbling duration is relevant to the physics of run-and-tumble interactions. Finally, I explore the effect of walls on the interacting run-and-tumble model by applying a perturbative graph-theoretic approach to the model with reflecting boundaries. Confining the particles in this way leads to a probability distribution in the low tumble limit with a much richer structure than the corresponding limit for the model on a periodic lattice. This limiting probability distribution indicates that an interaction over a finite distance emerges not just between the particles, but also between the particles and the reflecting boundaries. Together, these works provide a potential pathway towards understanding the clustering of self-propelled particles widely observed in active matter from a microscopic perspective.

The work presented in this thesis was inspired by one of the most fascinating classes of naturally occurring molecules: bipedal motor proteins from the kinesin, dynein and myosin superfamilies walk along cellular tracks, carrying out essential tasks, such as vesicle transport, muscle contraction or force generation. Although a few synthetic mimicks based on DNA have been described, small-molecule analogues that exhibit the most important characteristics of the biological walkers were still missing until recently. In this thesis, the design, synthesis and operation of several small-molecule walker-track systems is described. All presented systems share a similar molecular architecture, featuring disulfide and hydrazone walker-track linkages, yet deviate fundamentally in the mechanism and energy input that is required for directional walker transport. Chapter I includes an overview of the biological walker proteins, as well as a comprehensive review of the DNA-based mimicks published to date. A set of fundamental walker characteristics is identified and special emphasis is given to the underlying physical mechanisms. Chapter II describes a series of experiments, which lay the groundwork for all smallmolecule walker systems presented in the following Chapters of this thesis. The mutually exclusive nature of disulfide and hydrazone exchange under basic and acidic reaction conditions, was demonstrated using an unprecedented type of macrocycle. The first small-molecule walker-track system is described in Chapter III. Due to the passive nature of both the track and the walker unit, an oscillation of acidic and basic reaction conditions led to a directionally un-biased, intramolecular ‘diffusion’ of the walker unit along the track. Using an irreversible redox-reaction for one of the foot-track exchange reactions conferred a certain degree of directionality to the walking sequence, with the oxidant iodine providing the chemical fuel for the underlying Brownian information ratchet mechanism. Chapter IV contains a comprehensive investigation of the dynamic properties of a series of walker-track conjugates derived from the walker-track conjugate presented in Chapter III. The most significant observation was that ring strain appears to be a requirement for the emergence of directional bias, a phenomenon that has also been found in biological walkers. In Chapter V a different type of walker-track conjugate is described, in which the track plays an active role and light is used as the fuel required for directional walker transport. The key for achieving directionality was the presence of a stilbene unit as part of the molecular track, through which ring strain could be induced in the isomer where the walker unit bridges the E-stilbene linkage. Significantly, the underlying Brownian energy ratchet mechanism allowed walker transport in either direction of the molecular track. Chapters II to V are presented in the form of articles that have recently been published or will be published in due course in peer-reviewed journals. No attempt has been made to re-write this work out of context, other than to avoid repetition, insert crossreferences to other Chapters (where appropriate) and to ensure consistency of presentation throughout this thesis. Chapters II, III, IV and V are reproduced in the Appendix, in their published formats. The Outlook contains closing remarks about the scope and significance of the presented work as well as ideas for the design and operation of a next generation of small-molecule walkers, some of which are well under way in the laboratory.

The ubiquitous nature of symmetry lends itself to be taken for granted, however the breath of research on symmetry encompasses several disciplines. In engineering, studies centered on symmetry often address issues in dynamic systems theory, robotics, and gait rehabilitation. This thesis presents findings on two specific topics dealing with passively induced symmetry; dissimilar rotating systems and human gait. Past studies on passive symmetry in dynamic systems often incorporate physical coupling or a controller. This thesis presents a technique to passively induce symmetry between two dissimilar systems that are not physically connected. This work also presents a human gait study consisting of several elements that merge to provide a unique look at how walking symmetry and altered physical parameters (leg length and added weight) of the lower limbs are related. One aspect of this thesis shows the successful development of a general method to induce synchronization between any two dissimilar, uncoupled, rotating systems given the same degrees of freedom, initial angular dynamics, and applied torque. This method is validated with a simulation and subsequent comparison with two physical experiments. The results are in agreement, with slight variations due to the friction and damping of the physical systems. This is further expanded to include the induced symmetry of two systems that experience an external collision. Due to the highly non-linear nature of such systems, an analytical solution was not found; instead a numerical solution is presented that resulted in partial symmetry between systems. The gait study demonstrated that weighted walking and altered leg length have both independent and combined spatio-temporal effects on lower limb symmetry. While altered leg length alone resulted in higher gait asymmetry, the combination of the two physical changes increases this asymmetry to affect the same limb. This study also showed that cognitive and physically distracted walking does not have an added effect to the gait symmetry with passive physical changes. In addition, this study was able to demonstrate that the arm swinging that occurs during natural walking does not significantly alter spatial or temporal gait parameters.

Cette thèse est consacrée à l'étude des matrices aléatoires et à quelques unes de leurs applications en physique, en particulier en physique statistique et en physique quantique.C'est un travail essentiellement analytique complété par quelques simulations numériques Monte Carlo. Dans un premier temps j'introduis la théorie des matrices aléatoires de façon assez générale : je définis les principaux ensembles de matrices aléatoires (en particulier gaussiens) et décris leurs propriétés fondamentales (distribution des valeurs propres, densité, etc). Dans un second temps je m'intéresse à des systèmes physiques d'interfaces à l'équilibre qui peuvent être modélisés par des marcheurs ``vicieux'', c'est-à-dire des marcheurs aléatoires conditionnés à ne pas se croiser. On peut montrer que la distribution des positions des marcheurs à un temps donné est exactement celle des valeurs propres d'une matrice aléatoire. J'étudie ensuite un problème physique qui relève d'un domaine très différent, celui de l'information quantique, mais qui est également étroitement relié aux matrices aléatoires: celui de l'intrication pour des états aléatoires dans un système quantique bipartite (fait de deux sous-parties) de grande taille. Enfin je m'intéresse à certaines propriétés des matrices aléatoires comme la distribution du nombre de valeurs propres positives ou encore la distribution de la valeur propre maximale (loi de Tracy-Widom près de la moyenne et grandes déviations loin de la moyenne). / This thesis presents a study of random matrices and some applications in physics, in particular in statistical physics and quantum physics. This work is mostly analytic, but I also performed some Monte Carlo numerical simulations. First I introduce random matrix theory: I define the main random matrix ensembles (in particular Gaussian ensembles) and describe their fundamental properties (distribution of the eigenvalues, density...). Then I study a physical system of interfaces at equilibrium that can be modeled by ``vicious walkers'', ie random walkers that can not meet each other.One can show that the distribution of the positions of the walkers at a given time is the same as the distribution of the eigenvalues of a random matrix. I also consider a problem coming from a very different field, the field of quantum information theory, but that is also closely related to random matrices: the distribution of entanglement for random states in a large bipartite quatum system (made of two parts). Finally I study some properties of random matrices such as the distribution of the number of positive eigenvalues or the one of the maximal eigenvalue (Tracy-Widom and large deviations).

Conflict in recreation is a major problem for recreation managers who are trying to provide satisfying experiences for all recreationists. This thesis is about conflict between mountain-bikers and trampers. Mountain-biking has grown in popularity in New Zealand over the last ten years, and these increasing numbers have threatened the quality of walkers' and runners' recreational experiences, particularly in peri-urban areas. Conflict is a complex social interaction process which occurs around times of change. It involves the interplay of perceptions and attitudes, behaviour, and an incompatible situation. This complexity required the use of a range of methods to successfully understand the conflict between walkers and mountain-bikers. Like many other recreational conflicts, the conflict between bikers and trampers is asymmetrical - walkers dislike meeting bikers much more than bikers dislike meeting walkers. A majority of walker respondents disliked or strongly disliked meeting bikers on walking tracks. Walkers' questionnaire answers indicated that their greatest concerns with mountain-biking are (in order of decreasing importance) track damage and other environmental damage, personal safety, and the feeling that bikes interrupt their peace and quiet. Further exploration during in-depth interviews show that the perception of these problems are closely related to the way different users feel about that places that they use, and the way meetings with other users can be incorporated into the experiences of the recreationist. For walkers, meeting bikers is far more intrusive than vice-versa. Political activity aimed at eliminating bikers from many front country areas means that bikers are now developing a dislike of trampers who they see as intolerant and arrogant. Therefore, behaviour affects the escalation of conflict. In addition, wider social change has had an influence on this conflict. Changing economic wellbeing, less regular work hours, a perceived lack of time and a wider choice of activities have all impacted on recreation patterns in peri-urban areas, and on this conflict situation. In addition, this study has indicated that the concepts of specialisation and substitution may need modification. The use of qualitative methods has highlighted the narrow focus that researchers have used when studying these concepts. Both must be seen more broadly in the context of individuals' changing recreational needs both over the life cycle, and in the face of social change as outlined above.

DNA nanotechnology is a rapidly developing field that creates nanoscale devices from DNA, which enables novel interfaces with biological material. Their therapeutic use is envisioned and applications in other areas of basic science have already been found. These devices function at physiological conditions and, owing to their molecular scale, are subject to thermal fluctuations during both preparation and operation of the device. Troubleshooting a failed device is often difficult and we develop models to characterise two separate devices: DNA walkers and DNA origami. Our framework is that of continuous-time Markov chains, abstracting away much of the underlying physics. The resulting models are coarse but enable analysis of system-level performance, such as ‘the molecular computation eventually returns the correct answer with high probability’. We examine the applicability of probabilistic model checking to provide guarantees on the behaviour of nanoscale devices, and to this end we develop novel model checking methodology. We model a DNA walker that autonomously navigates a series of junctions, and we derive design principles that increase the probability of correct computational output. We also develop a novel parameter synthesis method for continuous-time Markov chains, for which the synthesised models guarantee a predetermined level of performance. Finally, we develop a novel discrete stochastic assembly model of DNA origami from first principles. DNA origami is a widespread method for creating nanoscale structures from DNA. Our model qualitatively reproduces experimentally observed behaviour and using the model we are able to rationally steer the folding pathway of a novel polymorphic DNA origami tile, controlling the eventual shape.

Este proyecto implica la creación y uso de una aplicación para pasear a los perros del hogar y nos patentiza la factibilidad de su desarrollo en base a investigaciones ejecutadas a personas entre los 18 y 39 años de edad que residen en Lima Moderna, de nivel socioeconómico A y B y que cuentan con al menos un canino dentro de su hogar. Debido a las actividades laborales, estudiantiles y familiares, los dueños de perros no cuentan con el tiempo idóneo para realizar la recreación que sus perros necesitan, lo que puede causar estrés, depresión o problemas de comportamiento en sus mascotas. Este resultado ha sido aprobado por la comunidad veterinaria, expertos en cuidado de perros y por dueños de perros que fueron participes de diversas entrevistas. A partir de nuestra investigación, encontramos que cada día más dueños de mascotas están dispuestos a obtener nuevos servicios para poder brindarles a sus perros una mejor calidad de vida. Por ello, se compromete a crear esta aplicación para que los amantes de los perros puedan caminar de forma segura utilizando la tecnología actual. Para su puesta en marcha, se estima una inversión inicial de S/. 32,215.00, la cual estará financiada en un 77 % por la caja Piura y 23 % por los accionistas de la empresa. El periodo de recuperación se dará después del tercer año de ejecución. / This project involves the creation and use of an application to walk the household dogs and shows us the feasibility of its development based on research carried out on people between 18 and 39 years of age who reside in Modern Lima, of socioeconomic level A and B and that they have at least one canine in their home. Due to work, student and family activities, dog owners do not have the ideal time to do the recreation that their dogs need, which can cause stress, depression or behavior problems in their pets. This result has been approved by the veterinary community, experts in dog care and by dog ​​owners who participated in various interviews. From our research, we find that more and more pet owners are willing to obtain new services in order to provide their dogs with a better quality of life. Therefore, he is committed to creating this application so that dog lovers can walk safely using current technology. For its start-up, an initial investment of S /. 32,215.00, which will be financed in a 77 % by “caja Piura” and 23 % by the shareholders. The recovery period will be after the third year of execution. / Trabajo de investigación