Modified stabilization method for the tibial tuberosity advancement technique: a biomechanical study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mechanical resistance of the modified stabilization method for the tibial tuberosity advancement technique: ex vivo experimental study in dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Numerical methods in multibody system dynamics

"Series: Solid mechanics and its applications, vol. 226"

Lanczos subspace filter diagonalization: Homogeneous recursive filtering and a low-storage method for the calculation of matrix elements

We develop a new iterative filter diagonalization (FD) scheme based on Lanczos subspaces and demonstrate its application to the calculation of bound-state and resonance eigenvalues. The new scheme combines the Lanczos three-term vector recursion for the generation of a tridiagonal representation of the Hamiltonian with a three-term scalar recursion to generate filtered states within the Lanczos representation. Eigenstates in the energy windows of interest can then be obtained by solving a small generalized eigenvalue problem in the subspace spanned by the filtered states. The scalar filtering recursion is based on the homogeneous eigenvalue equation of the tridiagonal representation of the Hamiltonian, and is simpler and more efficient than our previous quasi-minimum-residual filter diagonalization (QMRFD) scheme (H. G. Yu and S. C. Smith, Chem. Phys. Lett., 1998, 283, 69), which was based on solving for the action of the Green operator via an inhomogeneous equation. A low-storage method for the construction of Hamiltonian and overlap matrix elements in the filtered-basis representation is devised, in which contributions to the matrix elements are computed simultaneously as the recursion proceeds, allowing coefficients of the filtered states to be discarded once their contribution has been evaluated. Application to the HO2 system shows that the new scheme is highly efficient and can generate eigenvalues with the same numerical accuracy as the basic Lanczos algorithm.

Porous silicon optical filters in gas sensing applications

In this thesis, the gas sensing properties of porous silicon-based thin-film optical filters are explored. The effects of surface chemistry on the adsorption and desorption of various gases are studied in detail. Special emphasis is placed on investigating thermal carbonization as a stabilization method for optical sensing applications. Moreover, the possibility of utilizing the increased electrical conductivity of thermally carbonized porous silicon for implementing a multiparametric gas sensor, which would enable simultaneous monitoring of electrical and optical parameters, is investigated. In addition, different porous silicon-based optical filter-structures are prepared, and their properties in sensing applications are evaluated and compared. First and foremost, thermal carbonization is established as a viable method to stabilize porous silicon optical filters for chemical sensing applications. Furthermore, a multiparametric sensor, which can be used for increasing selectivity in gas sensing, is also demonstrated. Methods to improve spectral quality in multistopband mesoporous silicon rugate filters are studied, and structural effects to gas sorption kinetics are evaluated. Finally, the stability of thermally carbonized optical filters in basic environments is found to be superior in comparison to other surface chemistries currently available for porous silicon. The results presented in this thesis are of particular interest for developing novel reliable sensing systems based on porous silicon, e.g., label-free optical biosensors.

Sinkin stabiloiminen pilaantuneesta maa-aineksesta: 28 vuorokauden stabilointiajan riittävyys liukoisuustesteissä eri sinkkiyhdisteillä

Tässä kandidaatintyössä selvitettiin, onko 28 vuorokautta riittävä aika sinkillä pilaantuneen maaperän massastabilointiin, ja kuinka sinkin esiintymismuoto vaikuttaa sen stabilointiaikaan. Kokeellisessa osassa jäljiteltiin malmijätteessä, orgaanisessa aineksessa sekä liuenneena maaperässä esiintyvän sinkin stabiloitumista lisäämällä maanäytteeseen sinkkiä eri yhdisteinä; sinkkirakeina, -kloridina ja -asetaattina. Näytteet stabiloitiin sementti-lentotuhkaseoksella 1–28 vuorokauden pituisia ajanjaksoja, minkä jälkeen ne kuvattiin pyyhkäisyelektronimikroskoopilla (SEM) ja niille tehtiin liukoisuustestit. Liukoisuustestien tuloksista voidaan huomata sinkkikloridin stabiloituvan jo ensimmäisen vuorokauden aikana ja pysyvän samalla tasolla koko tarkasteluajan. Sinkkirakeiden ja -asetaatin stabiloituminen ei ole yhtä tasaista; alun sitoutumisen jälkeen niiden liukoisuuksissa on havaittavissa selkeät piikit 21 vuorokauden kohdalla. Tämän jälkeen ne alkavat sitoutua uudelleen. Tulosten perusteella sinkin esiintymismuoto vaikuttaa sen stabilointiaikaan, eikä 28:aa vuorokautta voida pitää riittävänä aikana sinkillä pilaantuneen maa-aineksen stabilointiin. Vaikka liukoinen sinkki stabiloituu jo yhdessä vuorokaudessa, ei malmijätteessä tai orgaanisessa aineksessa esiintyvä sinkki ehdi stabiloitua vakaalle tasolle vielä 28 vuorokaudenkaan aikana. Tämä tulisi ottaa huomioon suunniteltaessa ja toteutettaessa sinkkiä sisältävien maiden kunnostushankkeita.

Continuum resonances with shielded Coulomb-like potential and Efimov effect

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mapping wide row crops with video sequences acquired from a tractor moving at treatment speed

This paper presents a mapping method for wide row crop fields. The resulting map shows the crop rows and weeds present in the inter-row spacing. Because field videos are acquired with a camera mounted on top of an agricultural vehicle, a method for image sequence stabilization was needed and consequently designed and developed. The proposed stabilization method uses the centers of some crop rows in the image sequence as features to be tracked, which compensates for the lateral movement (sway) of the camera and leaves the pitch unchanged. A region of interest is selected using the tracked features, and an inverse perspective technique transforms the selected region into a bird’s-eye view that is centered on the image and that enables map generation. The algorithm developed has been tested on several video sequences of different fields recorded at different times and under different lighting conditions, with good initial results. Indeed, lateral displacements of up to 66% of the inter-row spacing were suppressed through the stabilization process, and crop rows in the resulting maps appear straight

Ravines in Angola. Causes and restraint methods

The Earth we know today was not always so. Over millions of years have undergone significant ch an g e s brought about by numerous geological phenomena aimed at your balance, some internal order, creating new geological formations and other external order smoothing formations previously created. From t h e tectonic standpoint, Angola is located in a relatively stable area which gives it a certain p ri v i l e g e w h e n compared with some Asian countries or even Americans where quite often occur earthquakes and volcanic eruptions. However, the same cannot be said in relation to the occurrence of an external geodynamics phenomena, such as the ravines, which in recent years has taken shape in many provinces, especially due to anthropogenic activity, giving rise to geological hazards, increasing the risk of damage in buildings and others infrastructures, losses direct or indirect in economic activities and loss of human lives. We understand that the reducing of these risks starts, in particular, by their identification, for later take preventive measures. This work is the result of some research work carried out by the authors through erosion courses of s o i l and stabilization of soils subject to erosion phenomena, carried out by Engineering Laboratory of Angola (LEA). For the realization of this work, we resorted to cartographic data query, literature, listening to s o m e o f the provincial representatives and local residents, as well as the observation in lo co o f s o m e af f e ct ed areas. The results allow us to infer that the main provinces affected by ravine phenomenon are located in Central and Northern highlands, as well as in the eastern region, and more recently in Cuando-Cub an go province. Not ruling out, however, other regions, such as in Luanda and Cabinda [1]. Relatively the causes, we can say that the ravines in Angola are primarily due to the combination of three natural factors: climate, topography and type of soil [2]. When we add the anthropogenic activit y , namely the execution of construction works, the drainage system obstructio n, exploration of m i n e ral s, agriculture and fires, it is verified an increasing of the phenomenon, often requiring immedi at e act i o n . These interventions can be done through structural or engineering measures and by the stabilization measures on the degraded soil cover [3]. We present an example of stabilization measures throu g h t h e deployment of a local vegetation called Pennisetum purpureum. It is expected that the results may contribute to a better understanding of the causes of the ravine phenomenon in Angola and that the adopted stabilization method can be adapted in other affected provinces in order to prevent and making the contention of the ravines.

A simplified method of stabilization and hemostasis for minimally invasive coronary artery bypass.

We describe a simple method to achieve both hemostasis and stabilization of the left anterior descending coronary artery during minimally invasive coronary artery bypass grafting. This technique allows the surgeon to perform a precise anastomosis of the left internal mammary artery to the target vessel on a beating heart.

An alternative method for purifying and detoxifying diphtheria toxin

Infections caused by Corynebacterium diphtheriae frequently induce situations in which very small doses of antigens injected intradermally can cause strong inflammatory reactions. This bacterium secretes the diphtheria toxin (DT), a virulence factor that can be lethal to the human organism at doses below 0.1 mu g/kg of body weight. The present work proposes alternative methods of DT purification using affinity chromatography and of DT detoxification through conjugating with the polymer methoxypolyethylene glycol activated (mPEG). Tests were performed to evaluate: the formation of edemas and the presence of dermonecrotic activity, in vitro cytotoxicity to Vero cells, the neutralizing activity of serum from guinea pigs immunized with the diphtheria toxoid inactivated with mPEG, and the immunogenic activity of the purified and modified toxin. The results indicated that purification with Blue Sepharose was an efficient method, yielding antigen purity equivalent to 2600 Lf/mg of protein nitrogen. The modification of the Purified Toxin with mPEG did not result in the formation of edema or necrosis although it was immunogenic and stimulated the formation of antibodies that could neutralize the Purified Toxin. The toxoid obtained from the purified toxin maintained its immunogenic characteristics, inducing antibodies with neutralizing activity; edema and necrosis were still observed, however. (C) 2011 Elsevier Ltd. All rights reserved.

A method to lower the detection limit for optical beat signals from a frequency-dithered stabilized laser

A narrow absorption feature in an atomic or molecular gas (such as iodine or methane) is used as the frequency reference in many stabilized lasers. As part of the stabilization scheme an optical frequency dither is applied to the laser. In optical heterodyne experiments, this dither is transferred to the RF beat signal, reducing the spectral power density and hence the signal to noise ratio over that in the absence of dither. We removed the dither by mixing the raw beat signal with a dithered local oscillator signal. When the dither waveform is matched to that of the reference laser the output signal from the mixer is rendered dither free. Application of this method to a Winters iodine-stabilized helium-neon laser reduced the bandwidth of the beat signal from 6 MHz to 390 kHz, thereby lowering the detection threshold from 5 pW of laser power to 3 pW. In addition, a simple signal detection model is developed which predicts similar threshold reductions.

Human ceruloplasmin and neurotransmitters: complex stabilization and crystallization

Dissertation to obtain a Master Degree in Molecular Genetics and Biomedicine at Faculty of Sciences and Technology,Universidade Nova de Lisboa

Component oriented method for simulation of multibody dynamics

Modular modelling, dynamics simulation, multibodies, O(N) method, closed loops, post-stabilization

Analysis of a finite volume element method for the Stokes problem

In this paper we propose a stabilized conforming finite volume element method for the Stokes equations. On stating the convergence of the method, optimal a priori error estimates in different norms are obtained by establishing the adequate connection between the finite volume and stabilized finite element formulations. A superconvergence result is also derived by using a postprocessing projection method. In particular, the stabilization of the continuous lowest equal order pair finite volume element discretization is achieved by enriching the velocity space with local functions that do not necessarily vanish on the element boundaries. Finally, some numerical experiments that confirm the predicted behavior of the method are provided.