PÊNDULO ANCORADO EM MINI-IMPLANTES: AVALIAÇÃO DENTÁRIA E ESQUELÉTICA

O aparelho Pêndulo é eficaz na correção das más oclusões de Classe II, com comprometimento dentoalveolar superior. No entanto, a perda de ancoragem caracterizada pela mesialização dos pré-molares superiores, e pela vestibularização e protrusão dos incisivos superiores, constitui um grave efeito colateral deste dispositivo. O objetivo deste estudo foi avaliar as possíveis alterações dentárias e esquelética, sagitais e verticais, decorrentes do uso do Pêndulo modificado, ancorado em mini-implantes. Dez indivíduos foram tratados neste estudo, sendo que telerradiografias em norma lateral foram realizadas no início do tratamento, e imediatamente após a remoção do Pêndulo. Em cada indivíduo foram instalados dois mini-implantes no palato, que receberam carga imediata por meio da ativação do Pêndulo modificado, apoiado nestes dispositivos de ancoragem temporária. Nenhum dos dentes avaliados apresentou alterações verticais estatisticamente significantes; o mesmo ocorreu para as alterações esqueléticas verticais e sagitais, e para o trespasse vertical e horizontal. Com relação às alterações estatisticamente significantes, o primeiro molar superior moveu-se para distal aproximadamente 5,6mm em 6,2 meses, e com inclinação distal média de 7,100. Os segundos pré-molares superiores distalizaram em média 2,7mm e inclinaram 5,550; já os segundos molares superiores moveram-se em média 4,6mm para distal com uma inclinação de 13,700; valores estes também considerados estatisticamente significantes. O sistema de distalização de molares superiores, composto pelo Pêndulo modificado ancorado em mini-implantes, mostrou-se eficaz na correção da má oclusão de Classe II, sem produzir os efeitos de perda de ancoragem. (AU)

PÊNDULO ANCORADO EM MINI-IMPLANTES - ANÁLISE EM MODELOS DIGITAIS

A distalização dos molares superiores é uma opção de tratamento da má oclusão de Classe II, quando o envolvimento é principalmente dentoalveolar. Dispositivos intrabucais como o aparelho Pêndulo, dispensam a colaboração do paciente quanto ao uso, porém promovem efeitos muitas vezes indesejáveis como a vestibularização dos dentes anteriores que participam na ancoragem e a inclinação dos molares distalizados. Após o surgimento dos Dispositivos de Ancoragem Temporária (DATs), como o mini-implante pode-se alcançar a ancoragem de forma previsível e eficiente. Com isto, por meio de um estudo prospectivo, foram avaliadas as alterações dentárias, promovidas pela distalização de molares superiores com um aparelho Pêndulo modificado, apoiado em dois mini-implantes instalados no palato de 10 indivíduos, sendo 2 do sexo feminino e 8 do masculino, com média de idade de 14,3 anos. A amostra foi composta por 20 modelos digitalizados em 3D, obtidos de em duas fases: no início do tratamento (T1) e após distalização com sobrecorreção de 1 mm (T2), permitindo quantificar as alterações dentárias sagitais, transversais e possíveis movimentos de rotação, angulação e movimentos verticais. Os resultados obtidos mostraram que no sentido sagital, houve uma efetiva distalização com significância estatística, para os segundos molares superiores; primeiros molares superiores em média de 4,34 mm e 3,91mm para o lado direito e esquerdo, respectivamente, e para os segundos pré-molares do lado direito e esquerdo de 2,06 mm e 1,95 mm, respectivamente. Porém, para os dentes anteriores, foi constatada a perda de ancoragem. No sentido transversal, o maior aumento ocorreu na região dos dentes posteriores. Os movimentos de rotação, angulação e vertical dos primeiros molares superiores, indicam que houve rotação mesiovestibular e inclinação distal das coroas destes dentes de ambos os lados; as medidas verticais, demonstram que houve movimento significativo apenas para o primeiro molar direito, com inclinação distal pela intrusão da cúspide distal. Este dispositivo mostrou-se eficaz na correção da Classe II em um tempo médio de 6,2 meses.(AU)

Developing a scalable model of recombinant protein yield from Pichia pastoris:the influence of culture conditions, biomass and induction regime

Background The optimisation and scale-up of process conditions leading to high yields of recombinant proteins is an enduring bottleneck in the post-genomic sciences. Typical experiments rely on varying selected parameters through repeated rounds of trial-and-error optimisation. To rationalise this, several groups have recently adopted the 'design of experiments' (DoE) approach frequently used in industry. Studies have focused on parameters such as medium composition, nutrient feed rates and induction of expression in shake flasks or bioreactors, as well as oxygen transfer rates in micro-well plates. In this study we wanted to generate a predictive model that described small-scale screens and to test its scalability to bioreactors. Results Here we demonstrate how the use of a DoE approach in a multi-well mini-bioreactor permitted the rapid establishment of high yielding production phase conditions that could be transferred to a 7 L bioreactor. Using green fluorescent protein secreted from Pichia pastoris, we derived a predictive model of protein yield as a function of the three most commonly-varied process parameters: temperature, pH and the percentage of dissolved oxygen in the culture medium. Importantly, when yield was normalised to culture volume and density, the model was scalable from mL to L working volumes. By increasing pre-induction biomass accumulation, model-predicted yields were further improved. Yield improvement was most significant, however, on varying the fed-batch induction regime to minimise methanol accumulation so that the productivity of the culture increased throughout the whole induction period. These findings suggest the importance of matching the rate of protein production with the host metabolism. Conclusion We demonstrate how a rational, stepwise approach to recombinant protein production screens can reduce process development time.

Understanding mobile phone usage while driving:mini-bus and taxi drivers' experiences in Istanbul

In emerging markets, the amount of mobile communication and the number of occasions mobile phones are used are increasing. More and more settings appropriate or not for mobile phone usage are being exposed. Although prohibited by many governments, there is evidence that use of new mobile devices while driving are somehow becoming current everyday practice, hence legitimatizing usage for many users. Dominant dangerous behavior in the absence of enforced legal framework is being deployed and has become routine for many m-users. This chapter adopts a qualitative case study approach (20 cases) to examine the public transport drivers' motives, logic and legitimacy processes. The question which these issues raise in the light of advancing m-technologies is: How do, in the context of emerging market, undesired emerging routines enactment get to be reflected upon and voluntarily disregarded to maximize the benefits of m-technologies while minimizing their drawbacks? Findings point out at multiple motives for usage including external social pressure through the ubiquitous 24/7 usage of mtechnology, lack of alternative communication protocol, real time need for action and from an internal perspectives boredoms, lack of danger awareness, blurring of the boundaries between personal and business life and lack of job fulfillment are uncovered as key factors. As secondary dynamic factors such as education, drivers work' histories, impunity, lack of strong consumer opposition appear central in shaping the development of the routines. © 2011, IGI Global.

The vibrational spectra of rectangular plates

The wire drive pulse-echo system has been extensively used to excite and measure modes of vibration of thin rectangular plates. The frequency spectra of different modes have been investigated as a function of the material elastic moduli and the plate geometry. Most of the work was carried out on isotropic materials. For square plates a wide selection of materials were used. These were made isotropic in their in-plane dimensions where the displacements are taking place. The range of rnaterials enabled the dependence on Poisson's ratio to be investigated. A method of determining the value of Poisson's ratio resulted from this investigation. Certain modes are controlled principally by the shear modulus. Of these the fundamental has two nodal lines across the plate surface. One of them, which has nodes at the corners, (the Lame mode) is uniquely a pure shear mode where the diagonal is a full wave length. One controlled by the Young's modulus has been found. The precise harmonic relationship of the Lame mode series in square and rectangular plates was established. Use of the Rayleigh-Lamb equation has extended the theoretical support. The low order modes were followed over a wide range of sides ratios. Two fundamental types of modes have been recognised; These are the longitudinal modes where the frequency is controlled by the length of the plate only and the 2~f product has an asymptotic value approaching the rod velocity. The other type is the in-plane flexural modes (in effect a flexurally vibrating bar where the -2/w is the geometrical parameter). Where possible the experimental work was related to theory. Other modes controlled by the width dimension of the plate were followed. Anisotropic materials having rolled sheet elastic symmetry were investigated in terms of the appropriate theory. The work has been extended to examine materials from welds in steel plates.

Flowback of solids through distribution plates of gas fluidized beds and associated phenomena

This work is concerned with a study of certain phenomena related to the performance and design of distributors in gas fluidized beds with particular regard to flowback of solid particles. The work to be described is divided into two parts. I. In Part one, a review of published material pertaining to distribution plates, including details from the patent specifications, has been prepared. After a chapter on the determination of the incipient fluidizing velocity, the following aspects of multi-orifice distributor plates in gas fluidized beds have been studied: (i) The effect of the distributor on bubble formation related to the way in which even distribution of bubbles on the top surface of the fluidized bed is obtained, e.g. the desirable pressure drop ratio ?PD/?PB for the even distribution of gas across the bed. Ratios of distributor pressure drop ?PD to bed pressure drop at which stable fluidization occurs show reasonable agreement with industrial practice. There is evidence that larger diameter beds tend to be less stable than smaller diameter beds when these are operated with shallow beds. Experiments show that in the presence of the bed the distributor pressure drop is reduced relative to the pressure drop without the bed, and this pressure drop in the former condition is regarded as the appropriate parameter for the design of the distributor. (ii) Experimental measurements of bubble distribution at the surface has been used to indicate maldistribution within the bed. Maldistribution is more likely at low gas flow rates and with distributors having large fractional free area characteristics (i.e. with distributors having low pressure drops). Bubble sizes obtained from this study, as well as those of others, have been successfully correlated. The correlation produced implies the existence of a bubble at the surface of an orifice and its growth by the addition of excess gas from the fluidized bed. (iii) For a given solid system, the amount of defluidized particles stagnating on the distributor plate is influenced by the orifice spacing, bed diameter and gas flow rate, but independent of the initial bed height and the way the orifices are arranged on the distributor plate. II. In Part two, solids flowback through single and multi-orifice distributors in two-dimensional and cylindrical beds of solids fluidized with air has been investigated. Distributors equipped with long cylindrical nozzles have also been included in the study. An equation for the prediction of free flowback of solids through multi-orifice distributors has been derived. Under fluidized conditions two regimes of flowback have been differentiated, namely Jumping and weeping. Data in the weeping regime have been successfully correlated. The limiting gas velocity through the distributor orifices at which flowback is completely excluded is found to be indepnndent of bed height, but a function of distributor design and physical properties of gas and solid used. A criterion for the prediction of this velocity has been established. The decisive advantage of increasing the distributor thickness or using nozzles to minimize solids flowback in fluidized beds has been observed and the opportunity taken to explore this poorly studied subject area. It has been noted, probably for the first time, that with long nozzles, there exists a critical nozzle length above which uncontrollable downflow of solids occurs. A theoretical model for predicting the critical length of a bundle of nozzles in terms of gas velocity through the nozzles has been set up. Theoretical calculations compared favourably with experiments.

The mechanics of continuous roller bending of plates

This research initiates a study of the mechanics of four roll plate bending and provides a methodology to investigate the process experimentally. To carry out the research a suitable model bender was designed and constructed. The model bender was comprehensively instrumented with ten load cells, three torquemeters and a tachometer. A rudimentary analysis of the four roll pre-bending mode considered the three critical bending operations. The analysis also gave an assessment of the model bender capacity for the design stage. The analysis indicated that an increase in the coefficient of friction in the contact region of the pinch rolls and the plate would reduce the pinch resultant force required to end a plate to a particular bend radius. The mechanisms involved in the four roll plate bending process were investigated and a mathematical model evolved to determine the mechanics of four roll thin plate bending. A theoretical and experimental investigation was conducted for the bending of HP30 aluminium plates in both single and multipass bending modes. The study indicated that the multipass plate bending mechanics of the process varied according to the number of bending passes executed and the step decrement of the anticipated finished bend radius in any two successive passes (i.e. the bending route). Experimental results for single pass bending indicated that the rollers normally exert a higher bending load for the steady-continous bending with the pre-inactive side roll oper?tive. For the pre-bending mode and the steady-continous bending mode with the pre-active side roll operative, the former exerted the higher loads. The single pass results also indicated that the force on the side roll, the torque and power steadily increased as the anticipated bend radius decreased. Theoretical predictions for the plate internal resistance to accomplish finished bend radii of between 2500mm and 500mm for multipass bending HP30 aluminium plates, suggested that there was a certain bending route which would effectively optimise the bender capacity.

Failure of steel gusset plates

This thesis examines the parameters associated with the failure of triangular steel gusset plates. Eighty two results are presented investigating the position of the applied load, the gusset plate height to length ratio, size, thickness, internal angle and the removal of the inside corner. The thickness of the loaded plate and its influence on the gusset plates failure is also investigated. Twenty two similar gusset plates were tested to investigate the welds connecting the gusset plate to the adjacent loaded and support edges. The experimental results are compared with existing methods, none of which cover all the variables tested. Some methods do not consider buckling and most of those that do are inadequate. Most of the methods do not accurately take account of the load position. An alternative method based on experimental observations is presented for design purposes. The method covers any combination of the variables tested. To test assumptions made in the theoretical work forty seven strut tests took place to investigate buckling characteristics and fifteen special gusset plates were also tested. The gusset plates were found to fail in an elastic-plastic buckling manner. A gusset plate has a specific moment of resistance capacity about it’s inside corner and the ultimate load that can be applied is dependent upon the position of the load relative to the supported edge. There is an optimum height to length ratio for strength and any increase in the internal angle from 90 degrees produces little change in moment capacity. The removal of small portions of the inside corner of a gusset plate has little effect upon its moment capacity. The loaded plate does not provide any significant moment of resistance to the applied load at failure. The main functions of the loaded and supported edge welds is to prevent the gusset plate from slipping from between the plates.

A study of stray load losses in core clamp plates of salient pole synchronous machines

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Potsdam Library of Astronomical Photographic Plates

ACM Computing Classification System (1998): J.2.

Software Tools for Digitization of Astronomical Photographic Plates

ACM Computing Classification System (1998): J.2.