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In this work, the use of antiferroelectric liquid crystals for high-end passive displays has been explored. Antiferroelectric gray levels arise from a double symmetric hysteresis loop that can be stabilized by a constant holding voltage. This driving scheme is passive multiplexing compatible, but limitations appear when the multiplexing rate increases. We have developed new waveforms and driving schemes for high multiplexing level at video rate. The problem of accumulated voltage on bias level arising from data voltages is tackled as well.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A protocol based on systematic experimental measurements to characterize the electro-optic behavior of chiral smectic liquid-crystal (LC) materials with V/W-shaped responses is presented. An experimental smectic LC material has been checked by use of this protocol. It has been found that results derived from this procedure permit a reasonable evaluation of the electro-optic performance of these LC materials as well as their capability to be used in high-end display applications. Publicado

Displays and Photonics Application Group (GDAF) is devoted to design and development of passive and active devices and sensors for their applications in WDM networks, CWDM, POF, and RF over fiber networks using different technologies such as optical fibers, liquid crystals, and integrated optics. The group is also very active in modeling, electrooptical characterization, and addressing electronics of LCDs. In this article we are going to describe the main activities carried out in the group. Displays and Photonics Application Group (GDAF) is devoted to design and development of passive and active devices and sensors for their applications in WDM networks, CWDM, POF, and RF over fiber networks using different technologies such as optical fibers, liquid crystals, and integrated optics. The group is also very active in modeling, electrooptical characterization, and addressing electronics of LCDs. In this article we are going to describe the main activities carried out in the group.

In the last years, chiral smectic liquid crystals with V-shaped electro-optic response have been reported as one of the most promising technologies for display applications. In this work,some experiments have been made in order to check electrooptical performance of this kind of materials. Particularly, frequency dependence of optical response and memory effect in transmission have been analyzed. Microscopic observations of intermediate transmission levels and measurements of apparent tilt angle and response time have been also carried out.

4 pages, 10 figures, 1 table.-- Contributed to: 3ª Reunión Española de Optoelectrónica (OPTOEL'03), Leganés, Madrid, Jul 14-16, 2003. In the last years, fiat liquid crystal displays (LCD) have experienced a great spreading, both in its applications as in its manufacturing technology. Ferroelectric Liquid Crystals (FLCs) is the technology on which the research has been mainly focused. This work was partially supported by the Spanish Ministry of Science and Technology, grant no. TIC2000-1594-C02-02. Publicado

Centro de alto rendimiento de vela en la expo de Lisboa

Surface-stabilized antiferroelectric liquid crystals (AFLCs) and V-shape smectics share the spontaneous generation of intermediate transmission states, i.e. analogue grayscale. On the other hand, liquid crystal on silicon (LCOS) appears to be a promising alternative to thin-film transistors (TFTs) in the preparation of reflective microdisplays and spatial light modulators (SLMs). The feasibility of preparing LCOS SLMs using AFLC and V-shaped LCs has been analyzed. A comparative study of a number of AFLC and V-shape materials as candidates for LCOS SLMs has been carried out. Test cells below 1 mum have been prepared using an ITO-coated transparent glass plate and an aluminized silicon back plate mimicking the actual LCOS device. AFLC waveforms compatible to low-voltage operation of the silicon backplane have been demonstrated. V-shape waveforms have been designed and demonstrated as well. The results show that both LC families may be employed in this specific application. Dynamic behavior, with frame rates over 200 Hz, is especially remarkable.

The equivalent circuit for a thresholdless antiferroelectric liquid crystal (TLAFLC) cell has been derived using an electrical model. The model may be used to predict the TLAFLC dynamic behavior. The electrical response in the time domain of TLAFLC cells upon certain hypothesis has been obtained. Optical characteristics related to these electrical features have been derived as well. The equivalent circuit model reasonably reproduces the voltage across the cell, switching currents and the optical hysteresis obtained by experimental methods. The procedure for determining the voltage-dependent capacitance due to induced spontaneous polarization is shown. On the basis of the proposed model, we also suggest a number of clues to optimize some electrical parameters of liquid crystal materials as well as driving schemes. Publicado

A novel tunable liquid crystal microaxicon array is proposed and experimentally demonstrated. The proposed structure is capable of generating tunable axicons (thousands of elements) of micrometric size, with simple control (four control voltages) and low voltage, and is totally reconfigurable. Depending on the applied voltages, control over the diameter, as well as the effective wedge angle, can be achieved. Controls over the diameter ranging from 107 to 77 μm have been demonstrated. In addition, a control over the phase profile tunability, from 12π to 24π radians, has been demonstrated. This result modifies the effective cone angle. The diameter tunability, as well the effective cone angle, results in a control over the nondiffractive Bessel beam distance. The RMS wavefront deviation from the ideal axicon is only λ∕3. The proposed device has several advantages over the existing microaxicon arrays, including being simple having a low cost. The device could contribute to developing new applications and to reducing the fabrication costs of current devices.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:41:11Z No. of bitstreams: 1 S1517-74912000000300003.pdf: 121695 bytes, checksum: 1890024b3d18bf84cae57bb17bdc00cd (MD5) Made available in DSpace on 2013-08-22T18:41:11Z (GMT). No. of bitstreams: 1 S1517-74912000000300003.pdf: 121695 bytes, checksum: 1890024b3d18bf84cae57bb17bdc00cd (MD5) Previous issue date: 2000-09-01 Made available in DSpace on 2013-09-30T19:27:33Z (GMT). No. of bitstreams: 2 S1517-74912000000300003.pdf: 121695 bytes, checksum: 1890024b3d18bf84cae57bb17bdc00cd (MD5) S1517-74912000000300003.pdf.txt: 16816 bytes, checksum: 394f9daa9fc8217b93d7f3d8d7d20c50 (MD5) Previous issue date: 2000-09-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:07:38Z No. of bitstreams: 2 S1517-74912000000300003.pdf: 121695 bytes, checksum: 1890024b3d18bf84cae57bb17bdc00cd (MD5) S1517-74912000000300003.pdf.txt: 16816 bytes, checksum: 394f9daa9fc8217b93d7f3d8d7d20c50 (MD5) Made available in DSpace on 2014-05-20T15:07:38Z (GMT). No. of bitstreams: 2 S1517-74912000000300003.pdf: 121695 bytes, checksum: 1890024b3d18bf84cae57bb17bdc00cd (MD5) S1517-74912000000300003.pdf.txt: 16816 bytes, checksum: 394f9daa9fc8217b93d7f3d8d7d20c50 (MD5) Previous issue date: 2000-09-01 No presente trabalho, analisou-se a eficácia de uma nova técnica de esterilização de instrumental odontológico. Limas endodônticas contaminadas com Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus foram esterilizadas em plasma de oxigênio formado através de uma descarga elétrica contínua de 75 mA. Os resultados demonstraram efetiva eliminação dos microrganismos testados, utilizando-se um processo a baixas temperaturas e em tempos menores que os preconizados para processos convencionais (forno de Pasteur e autoclave). Microrganismos gram-negativos foram destruídos em 1 minuto de exposição e gram-positivos em 10 minutos. The present paper reports the effectiveness of a new sterilization technique for endodontic files contaminated with Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus in oxygen plasma formed through a continuous electric discharge of 75 mA. The results demonstrated effective elimination of the tested microorganisms, using a process in low temperatures and which requires less time than that established for conventional processes (Pasteur s oven and autoclave). Gram-positive microorganisms such as Staphylococcus aureus, require more time of plasma bombardment than Gram-negative microorganisms. Files contaminated with Pseudomonas aeruginosa and Escherichia coli were sterilized within a 1-minute exposure, while Staphylococcus aureus required 10 minutes. Universidade de Taubaté Departamento de Odontologia Instituto Tecnológico da Aeronáutica Departamento de Odontologia Departamento de Física Universidade Estadual Paulista Faculdade de Odontologia de São José dos Campos Departamento de Biopatologia e Diagnóstico Universidade Estadual Paulista Faculdade de Odontologia de São José dos Campos Departamento de Biopatologia e Diagnóstico

In this study, a novel liquid crystal array based on modal control principle is proposed and demonstrated. The advanced device comprises a six striped electrode structure that forms a configurable 2D matrix of optical elements. A simulation program based on the Frank-Oseen equations and modal control theory has been developed to predict the device electrooptic response, that is, voltage distribution, interference pattern and unwrapped phase. A low-power electronics circuit, that generates complex waveforms, has been built for driving the device. A combined variation of the waveform amplitude and phase has provided a high tuning versatility to the device. Thus, the simulations have demonstrated the generation of a liquid crystal prism array with tunable slope. The proposed device has also been configured as an axicon array. Test measurements have allowed us to demonstrate that electrooptic responses, simulated and empirical, are fairly in agreement.

This study evaluated the physicochemical and microbiological characteristics of rainwater and water samples taken from rainfall simulation over a roof and aircraft parking areas at Sao Paulo International Airport (SPIA), Brazil, aiming its reuse in non-potable situations. The results achieved did not indicate the presence of Volatile Aromatic Hydrocarbons, Polycyclic Aromatic Hydrocarbons, As, Cr, Hg and Cd. The results were compared with Brazilian and international guidelines. It indicated a low potential for pollution associated with the analysed waters. We concluded that rainwater is a viable alternative and it could save almost 25% of the whole water consumption at the airport.

The presence of gas in the bladder wall and/or lumen (emphysematous cystitis) is an uncommon disease entity that may be caused by infectious organisms. Diabetes and chronic urinary infection are predisposing factors. Its clinical features are unspecific and the prognosis depends on the degree of aggressiveness at presentation. Early diagnosis and treatment (bladder drainage + antibiotics) are very important in order to resolve the condition before severe sequelae are caused. We report on 75-year-old diabetic female with mild emphysematous cystitis caused by Clostridium perfringens which resolved with bladder drainage and antibiotics. The incidence, forms of presentation, pathogenesis, diagnosis and treatment of this condition are discussed.

Abdominal desmoid tumor or fibromatosis is a benign non-urological connective tumor which can be mistaken for a urological tumor due to its localization (generally in muscles and aponeurosis of the abdominal wall). It is locally invasive and potentially recurrent. We report on a 53-year-old male with abdominal desmoid tumor whose only symptom was pain. The clinical diagnosis was corroborated by the US and CT findings and confirmed by anatomopathological findings. Wide local surgical excision is the treatment of choice since hormone therapy, radiotherapy and chemotherapy achieved scant results.

The diagnosis of the accessory spleen, if unsuspected, is basically anatomopathological due to its frequency and, above all, its nonspecific clinical features. We report a case of a retroperitoneal mass that was shown to be composed of accessory splenic tissue.

Between June 1986 and December 1991, 125 kidneys were transplanted in our hospital. Survival results of patients per annum was 94%, 90% of which represent grafts. Regarding the complications occurred in our series the most frequent ones were medical followed by surgical [urological (4%), vascular (2.4%) and others derived from the surgical procedure (20%)]. It was necessary to perform 5 transplantectomies.

We describe an improved measurement of tissue absorption of light by using a mirage effect due to the thermal gradient at the tissue surface. The laser beam enters a prism where internal reflection is highly dependent on the incident angle. The system is calibrated using an acoustic-optical cell. Finally, we discuss design of a compact system which can produce an electrical signal related directly with the sample optical radiation absorption.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Analysis of results and complications of retrograde rigid ureterorenoscopies (URS) performed in our unit between August 1985 and June 1990. Our series includes 122 URS performed in 106 patients: 68% female and 32% male. A rigid ureteroscopy Storz 11.5 Ch was used. URS indications were: 72% treatment of ureteral lithiasis, 14% diagnosis, 7% treatment of ureteral tumores and 3% other reasons. Treated lithiasis were predominantly located in the pelvic ureter. Overall success in the treatment of lithiasis was 92.86% in "primary" lithiasis, and 71.43% in post-ESWL. URS allowed us to resolve troubles of differential diagnosis in 93.75% of cases. With a complications rate of 19.7%, only 3.28% were considered relevant.

The ectopic ureter opening to the seminal vesicle is uncommon in the male and even less in a duplex kidney. It commonly presents as recurrent urinary infection with pelviperineal pain. Treatment is by heminephrectomy with total ureterectomy and removal of the seminal vesicle if it is cystic. Herein we describe a 70-year-old patient who had previously undergone a heminephrectomy and partial ureterectomy due to an ectopic ureter opening to the seminal vesicle of the ureter of the upper pelvis of the left kidney. The patient was submitted to a second ureterectomy procedure due to pyoureter in the ureteral stump. The main features of this pathological condition are described and the surgical approach is discussed.