Avaliação da estabilidade da cirurgia de avanço mandibular através da superposição de modelos tridimensionais

Embora a cirurgia de avanço mandibular seja considerada um procedimento altamente estável, existem algumas preocupações clínicas em relação a mudanças nos côndilos e nos segmentos proximais, que podem levar a recidiva sagital e abertura de mordida. A avaliação dos resultados da cirurgia através de ferramentas de geração e superposição de modelos virtuais tridimensionais (3D) permite a identificação e quantificação dos deslocamentos e remodelação óssea que podem ajudar a explicar as interações entre os componentes dentários, esqueléticos e de tecido mole que estão relacionados a resposta ao tratamento. Este estudo observacional prospectivo avaliou, através de tomografia computadorizada de feixe cônico (CBCT), mudanças na posição/remodelação 3D dos ramos mandibulares, côndilos e mento. Assim, exames CBCT de 27 pacientes foram adquiridos antes da cirurgia (T1), imediatamente após a cirurgia(T2), e 1 ano após a cirurgia(T3). Uma técnica automática de superposição na base do crânio foi utilizada para permitir a avaliação das mudanças ocorridas nas regiões anatômicas de interesse (RAI). Os deslocamentos foram visualizados e quantificados em mapas coloridos 3D através da ferramenta de linha de contorno (ISOLINE). Pelo teste t pareado compararam-se as mudanças entre T1-T2 e T2-T3. O coeficiente de correlação de Pearson verificou se os deslocamentos ocorridos nas RAI foram correlacionados entre si e entre os tempos de avaliação. O nível de significância foi determinado em 0,05. O avanço mandibular médio foi de 6,813,2mm em T2 e 6,363,41mm em T3 (p=0,13). Entre T2 e T3, a posição do mento variou positivamente (≥2mm) em 5 pacientes negativamente em 7. 12% dos pacientes sofreram recidivas ≥4mm. Para todas as outras RAI avaliadas, apenas a porção inferior dos ramos (lado direito - 2,342,35mm e lado esquerdo 2,972,71mm) sofreram deslocamentos médios >2mm com a cirurgia. No acompanhamento em longo prazo, esse deslocamento lateral da porção inferior dos ramos foi mantido (lado direito - 2,102,15mm, p=0,26; e lado esquerdo -2,762,80, p=0,46), bem como todos os outros deslocamentos observados (p>0,05). As mudanças na posição do mento foram correlacionadas a adaptações pós-cirúrgicas nos bordos posteriores dos ramos (esquerdo r=-0,73 e direito r=-0,68) e côndilos (esquerdo r=-0,53 e direito r=-0,46). Os deslocamentos médios sofridos pelas estruturas do lado esquerdo foram suavemente maiores do que no direito. Correlações dos deslocamentos ocorridos entre T1-T2 e T2-T3 mostraram que: os deslocamentos dos côndilos esquerdos com a cirurgia foram negativamente correlacionados às adaptações pós-cirúrgicas destes (r=-0,51); e que o deslocamento da porção superior do ramo esquerdo com a cirurgia foi correlacionado à adaptação pós-cirúrgica ocorrida nos bordos posteriores (r=0,39) e côndilos do mesmo lado (r=0,39). Pode-se concluir que: (1) os deslocamentos causados pela cirurgia foram de modo geral estáveis no acompanhamento de 1 ano, mas identificou-se uma considerável variação individual; (2) as mudanças pós-cirúrgicas na posição do mento foram correlacionadas a adaptações sofridas pelos côndilos e bordos posteriores dos ramos; e que (3) deslocamentos suavemente maiores causados pela cirurgia nas estruturas do lado esquerdo levaram a maiores adaptações pós-cirúrgicas no segmento proximal deste lado.

近衍射极限半导体激光束波面检测

在星间半导体激光通信系统中，如何检测发射光束波面的质量是个较难处理的问题，为了较好地解决这一问题，在简单介绍白光横向双剪切干涉仪的基础上，报道了用此干涉仪对近衍射极限半导体激光光束波面的检测，在此基础上推导出计算远场发散度的公式。实验测得近场光束的波高差为0．2A，通过夫朗和费衍射求得光束的发散度仅为64．8μrad，这表明光束接近光学衍射极限。同时，表明双剪切干涉仪灵敏度高、实用性好。

Determination of the activity of nitrifying bacteria in surface waters by a modified BOD-test. [Translation from: Zentbl.Bakt.Parasitkde 156(1) 414-421, 1972. ]

A modified method of the Biochemical oxygen demand (BOD)test was applied in order to find out the seasonal changing activity of the nitrifying bacteria in surface waters. Samples were taken from the River Elbe near Teufelsbrueck.

Method for measuring the lateral aberrations of a lithographic projection system with mirror-symmetric FOCAL marks

A novel method for measuring the imaging quality of a projection system with mirror-symmetric FOCAL marks is proposed, and the principle of the method is described. Through experiments, it is demonstrated that not only the axial aberrations but also the lateral aberrations can be measured with high accuracy by the method. The advantages of the method include obtaining more aberrations than the FOCAL technique and making it much simpler to perform a full-scale measurement of the imaging quality of a lithographic projection system. (C) 2006 Society of Photo-Optical Instrumentation Engineers.

Analysis of lateral-spread photorefractive planar lenses

The photorefractive planar lens for converting a vertical incident plane wave to a lateral-spread spherical wave and vice versa, is suggested. Using the two-beam coupled-wave theory, the coupled wave equations are derived and their half-analytical solutions are also given in terms of an infinite series. The diffraction properties (beam profiles, diffraction efficiency) of the local volume grating in the lens are presented. And the focusing property of the lens is discussed and compared with that of an ideal convergent spherical wave. It is demonstrated that the suggested photorefractive planar lens shows a good focusing effect. (c) 2004 Elsevier GmbH. All rights reserved.

Effects of density differences on lateral mixing in open-channel flows

This study investigates lateral mixing of tracer fluids in turbulent open-channel flows when the tracer and ambient fluids have different densities. Longitudinal dispersion in flows with longitudinal density gradients is investigated also.

Lateral mixing was studied in a laboratory flume by introducing fluid tracers at the ambient flow velocity continuously and uniformly across a fraction of the flume width and over the entire depth of the ambient flow. Fluid samples were taken to obtain concentration distributions in cross-sections at various distances, x, downstream from the tracer source. The data were used to calculate variances of the lateral distributions of the depth-averaged concentration. When there was a difference in density between the tracer and the ambient fluids, lateral mixing close to the source was enhanced by density-induced secondary flows; however, far downstream where the density gradients were small, lateral mixing rates were independent of the initial density difference. A dimensional analysis of the problem and the data show that the normalized variance is a function of only three dimensionless numbers, which represent: (1) the x-coordinate, (2) the source width, and (3) the buoyancy flux from the source.

A simplified set of equations of motion for a fluid with a horizontal density gradient was integrated to give an expression for the density-induced velocity distribution. The dispersion coefficient due to this velocity distribution was also obtained. Using this dispersion coefficient in an analysis for predicting lateral mixing rates in the experiments of this investigation gave only qualitative agreement with the data. However, predicted longitudinal salinity distributions in an idealized laboratory estuary agree well with published data.

Method for measuring the lateral aberrations of a lithographic projection system with mirror-symmetric FOCAL marks

A novel method for measuring the imaging quality of a projection system with mirror-symmetric FOCAL marks is proposed, and the principle of the method is described. Through experiments, it is demonstrated that not only the axial aberrations but also the lateral aberrations can be measured with high accuracy by the method. The advantages of the method include obtaining more aberrations than the FOCAL technique and making it much simpler to perform a full-scale measurement of the imaging quality of a lithographic projection system. (C) 2006 Society of Photo-Optical Instrumentation Engineers.

Ecological effects of trial pumpings in the Upper Lambourn: Stage 1 group pumping test Upper Lambourn group, September - November 1975

This report to the Thames Water Authority and Central Water Planning Unit is on research carried out in conjunction with the Stage 1 Group Pumping Test of five boreholes in the upper Lambourn Group for a period of three months in September, October and November 1975. The aim of the study was to assess the ecological effects of the pumpin g of five bore-holes in the upper Lambourn. That is, to determine how the seasonal sequence of ecological events in the river differed from what would hav e occurred had no pumping taken place. Since this 'experiment' has no control it is not possible to make a direct assessment. Nevertheless, by careful monitoring of ecological events before, during and after the pumping it is possible to document changes in th e river and by reference to the data already available for the Rive r Lambourn, normal seasonal changes in the flora and fauna can be separated from changes which may be attributable to the pumping and subsequent events.

Progress report on fish counting on the Rivers Itchen and Test

This progress report summarises work on NSHEB Mark 10 fish counters which are installed at Woodmill on the River Itchen and Nurseling Mill and Connegar Bridge on the River Test. Counters are evaluated and salmon behaviour regarding the counters examined. The report includes a a list of equipment needed for the efficient running of the project in the future.

Imaging the earth with ambient noise and earthquakes

In this thesis, I develop the velocity and structure models for the Los Angeles Basin and Southern Peru. The ultimate goal is to better understand the geological processes involved in the basin and subduction zone dynamics. The results are obtained from seismic interferometry using ambient noise and receiver functions using earthquake- generated waves. Some unusual signals specific to the local structures are also studied. The main findings are summarized as follows:

(1) Los Angeles Basin

The shear wave velocities range from 0.5 to 3.0 km/s in the sediments, with lateral gradients at the Newport-Inglewood, Compton-Los Alamitos, and Whittier Faults. The basin is a maximum of 8 km deep along the profile, and the Moho rises to a depth of 17 km under the basin. The basin has a stretch factor of 2.6 in the center decreasing to 1.3 at the edges, and is in approximate isostatic equilibrium. This "high-density" (~1 km spacing) "short-duration" (~1.5 month) experiment may serve as a prototype experiment that will allow basins to be covered by this type of low-cost survey.

(2) Peruvian subduction zone

Two prominent mid-crust structures are revealed in the 70 km thick crust under the Central Andes: a low-velocity zone interpreted as partially molten rocks beneath the Western Cordillera – Altiplano Plateau, and the underthrusting Brazilian Shield beneath the Eastern Cordillera. The low-velocity zone is oblique to the present trench, and possibly indicates the location of the volcanic arcs formed during the steepening of the Oligocene flat slab beneath the Altiplano Plateau.

The Nazca slab changes from normal dipping (~25 degrees) subduction in the southeast to flat subduction in the northwest of the study area. In the flat subduction regime, the slab subducts to ~100 km depth and then remains flat for ~300 km distance before it resumes a normal dipping geometry. The flat part closely follows the topography of the continental Moho above, indicating a strong suction force between the slab and the overriding plate. A high-velocity mantle wedge exists above the western half of the flat slab, which indicates the lack of melting and thus explains the cessation of the volcanism above. The velocity turns to normal values before the slab steepens again, indicating possible resumption of dehydration and ecologitization.

(3) Some unusual signals

Strong higher-mode Rayleigh waves due to the basin structure are observed in the periods less than 5 s. The particle motions provide a good test for distinguishing between the fundamental and higher mode. The precursor and coda waves relative to the interstation Rayleigh waves are observed, and modeled with a strong scatterer located in the active volcanic area in Southern Peru. In contrast with the usual receiver function analysis, multiples are extensively involved in this thesis. In the LA Basin, a good image is only from PpPs multiples, while in Peru, PpPp multiples contribute significantly to the final results.

Papel de la N-nervonil esfingomielina en la organización lateral y la estabilidad nanomecánica de bicapas lipídicas

Los lípidos de las membranas biológicas no son perfectamente miscibles entre sí, con frecuencia dan origen a “dominios” bidimensionales separados lateralmente cuando se resuspenden en agua. Las mezclas esfingomielina/dioleilfosfatidilcolina/colesterol dan origen con frecuencia a dominios, pero esto no ocurre cuando la esfingomielina es insaturada (p. ej. N-nervonil esfingomielina). En este trabajo se han aplicado técnicas calorimétricas y estructurales para estudiar el comportamiento de mezclas N-nervonil esfingomielina/dioleilfosfatidilcolina/colesterol/ceramida. En presencia de ceramida y de N-nervonil esfingomielina se observa formación de dominios laterales, al contrario de lo que ocurría en ausencia de ceramida.