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Synthesis and characterization of glass-ceramic microspheres for thermotherapy

Martinelli, José Roberto; Sene, Frank Ferrer; Kamikawachi, Cristiane Naomi; Partiti, Carmen Silvia de Moya; Cornejo, Daniel Reinaldo
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.73%
Glass microspheres containing radionuclides are used to treat liver cancer. A promising alternative therapy is being developed based on the magnetic hyperthermia which is related to the heat supplied by a magnetic material under an alternating current magnetic field. The advantage of this option is that most of killed cells are cancer cells which are more susceptible to the temperature raise. In the present work aluminum iron silicate glasses containing minor glass modifiers and nucleating agents were synthesized as irregular shape particles which were further transformed in microspheres by using a petrol liquefied gas-oxygen torch. The optimized processing parameters which lead to microspheres that give a response to the magnetic field were determined. The dissolution rate in water at 90 degrees C was determined to be 3 x 10(-8) g cm(-2) min(-1). The microsphere size distribution was determined by laser scattering. The crystalline phase responsible for the ferromagnetic response was identified as magnetite. Since this phase has a high saturation magnetization and high Curie temperature, it is potentially useful for biomedical applications. The hysteresis magnetic loop was measured for materials produced in different conditions, and some of them showed to be appropriated for thermotherapy. The ratio Fe(3+)/Fe(total) was determined by Mossbauer spectroscopy. (C) 2010 Elsevier B.V. All rights reserved.

Synthesis and characterization of phosphate glass microspheres for radiotherapy applications

SENE, Frank F.; MARTINELLI, Jose R.; OKUNO, Emico
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.82%
Class microspheres containing the radioisotope (32)P, a beta(-) particle emitter, and half-life of 14.3 days, can be easily introduced in specific human organs such as liver, pancreas. and uterus to kill cancer cells. In the present work phosphate glass microspheres were produced with different compositions and particle size distribution in the range of 20- 30 mu m. Two different thermal processes were used to spherodize glass particles originally with irregular shapes. Samples were characterized by X-rays diffraction to check the amorphous structure, energy dispersive X-rays fluorescence spectroscopy to determine the final glass composition, and Fourier transformed infrared spectroscopy to determine the structural groups in the glass structure. The dissolution rate of glass samples in water was determined at 90 degrees C, and in simulated body fluid (SBF) at 37 degrees C. Classes with dissolution rates close to 10(-5) g/(cm(2) day) were obtained, which make them suitable for the present application. Scanning electron microscopy was used to evaluate the shape of the microspheres before and after the dissolution tests. The cytotoxicity tests showed that these microspheres can be used for biological applications. (C) 2008 Elsevier B.V. All rights reserved.; CNPq[471712/2004-3]; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fapesp[05/53241-9]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Processamento e propriedades de compósitos de poliamida 6.6 reforçada com partículas de vidro reciclado.; Processing and properties of composites polyamide 6.6 with waste glass particles.

Factori, Irina Marinho
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 08/10/2009 PT
Relevância na Pesquisa
46.38%
A poliamida 6.6 é um dos mais importantes membros da família das poliamidas, principalmente pelas excelentes propriedades de engenharia, como desempenho mecânico e térmico. A sua área de aplicação é ampliada pela adição de cargas inorgânicas. Dentre estas cargas podemos destacar as fibras de vidro, talco, wollastonita e micro esferas de vidro, cargas estas industrialmente conhecidas. Por outro lado, partículas de vidro reciclado provenientes de descarte nunca foram estudadas como reforço de poliamida 6.6, em especial as partículas menores, que são rejeitadas na reciclagem pela indústria do vidro por apresentarem dificuldade de transporte para os fornos, podendo depositar-se nos refratários (fenômeno de arraste), aumentando sua taxa de corrosão, assim reduzindo a vida útil dos fornos. Além disso, essas partículas têm formato irregular. Desse modo, compósitos de poliamida 6.6 reforçados com porcentagens variadas de vidro reciclado e cargas usualmente empregadas pela indústria foram processados em laboratório, com o auxílio de uma extrusora dupla-rosca e as amostras avaliadas foram obtidas por injeção. As seguintes propriedades dos compósitos foram avaliadas: resistência à tração, alongamento na ruptura...

Estudo do processo de esferolização de partículas vítreas visando a aplicação em radioterapia interna seletiva; Study of the spheroidization process of glass particles for selective internal radiotherapy

Barros Filho, Eraldo Cordeiro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/02/2012 PT
Relevância na Pesquisa
46.82%
A radioterapia interna seletiva é uma alternativa para o tratamento do carcinoma hepatocelular. Nesta terapia, microesferas de vidro contendo radionuclídeos são introduzidas no fígado por meio de um cateter acoplado à artéria hepática dos pacientes e são retidas em regiões microvasculares que alimentam o tecido lesado. Estas micropartículas aniquilam as células cancerosas por meio da radiação β-, e, quando simultaneamente emitem raios γ, podem também ser utilizadas para imageamento do tumor. As partículas vítreas devem possuir o formato esférico para não provocar hemorragias desnecessárias e também diâmetro adequado para otimizar o bloqueio efetivo da alimentação do tumor e evitar a migração para outros órgãos que poderia causar doses em tecidos sadios. Além disso, devem ter durabilidade química adequada e não serem citotóxicas. A distribuição do tamanho de microesferas depende de muitos parâmetros como a razão de aspecto, formação de aglomerados, e temperatura de processamento. No presente trabalho é apresentado um estudo do processo de esferolização de partículas vítreas caracterizadas por difração de raios X, espectrometria de fluorescência de raios X por energia dispersiva...

Caracterização e aplicabilidade de vidro de tela de LCD em matriz de Poliamida-6.; Use of glass from LCD screen in a Polyamide-6 matrix.

Massaro, Natalia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/10/2013 PT
Relevância na Pesquisa
46.37%
Monitores de LCD (Liquid Crystal Display) para computador são equipamentos eletroeletrônicos que têm como destino de descarte os aterros sanitários ou a incineração. O vidro presente nas telas de LCD pode ser reaproveitado como carga em matrizes poliméricas para melhorar as propriedades mecânicas das mesmas ampliando o seu mercado de aplicação. A Poliamida-6 (PA-6) é um dos mais importantes plásticos de engenharia comercializados, devido as suas ótimas propriedades mecânicas e térmicas. Porém, a PA-6 é higroscópica e apresenta baixa estabilidade dimensional. A adição de cargas inorgânicas além de elevar o módulo de elasticidade do polímero, eleva a estabilidade dimensional devido à redução da absorção de água. Desse modo, compósitos de PA-6 reforçados com cargas particuladas provenientes de telas de LCD e microesferas de vidro, cargas usualmente empregadas pela indústria, foram processados em laboratório em extrusora dupla-rosca. Os corpos de prova foram obtidos por injeção e suas propriedades foram avaliadas por ensaio de resistência à tração, ensaio de resistência ao impacto Izod, com e sem entalhe, microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC), análise termogravimétrica (TG) e difração de raios X (DRX). Os resultados indicaram que todas as cargas estudadas provocaram redução na resistência à tração da matriz de PA-6 e em sua resistência ao impacto...

Estudo da sinterização de vidros aluminossilicatos por calorimetria exploratória diferencial; Evaluation of aluminossilicate glass sintering during differential scanning calorimetry

Souza, Juliana Pereira de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/02/2015 PT
Relevância na Pesquisa
36.56%
Neste trabalho foi investigada uma mudança na linha base observada em curvas de calorimetria exploratória diferencial em um trabalho onde microesferas de vidros aluminossilicatos contendo Ho foram estudados para a aplicação em radioterapia interna seletiva para o tratamento de carcinoma hepatocelular. Os vidros com composição nominal 53,7 SiO2 .10,5 Al2O3 . 35,8 MgO em %mol foram produzidos pelo método de fusão tradicional. As fritas obtidas foram moídas e peneiradas na faixa de 45 a 63 μm. O material foi utilizado para produzir microesferas pelo método de esferolização por queda gravitacional. O pó de vidro e as microesferas foram caracterizados por espectrometria de fluorescência de raios X, difração de laser, difração de raios X, calorimetria exploratória diferencial, análise térmica diferencial, termogravimetria, espectrometria de massa e microscopia eletrônica de varredura. Após as análises térmicas foram formadas pastilhas nos cadinhos que foram analisadas por microscopia eletrônica de varredura, difração de raios X e picnometria a gás He. A mudança na linha base foi associada ao processo de sinterização por fluxo viscoso e ocorre devido a diminuição do fluxo de calor detectado devido à retração da amostra. Outros processos como cristalização concomitante com a sinterização também foram estudados.; In this work a difference in the baseline in differential scanning calorimetry analyses...

The effect of starch and starch-bioactive glass composite microparticles on the adhesion and expression of the osteoblastic phenotype of a bone cell line

Silva, G. A.; Coutinho, O. P.; Ducheyne, P.; Shapiro, I. M.; Reis, R. L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2007 ENG
Relevância na Pesquisa
36.15%
There is a clear need for the development of microparticles that can be used simultaneously as carriers of stem/progenitor cells and as release systems for bioactive agents, such as growth factors or differentiation agents. In addition, when thinking on bone-tissueengineering applications, it would be very useful if these microparticles are biodegradable and could be made to be bioactive. Microparticles with all those characteristics could be cultured together with adherent cells in appropriate bioreactors to form in vitro constructs that can then be used in tissue-engineering therapies. In this work, we have characterized the response of MC3T3-E1 pre-osteoblast cells to starch-based microparticles. We evaluated the adhesion, proliferation, expression of osteoblastic markers and mineralization of cells cultured at their surface. The results clearly show that MC3T3-E1 pre-osteoblast cells adhere to the surface of both polymeric and composite starch-based microparticles and express the typical osteoblastic marker genes. Furthermore, the cells were found to mineralize the extracellular matrix (ECM) during the culture period. The obtained results indicate that starch-based microparticles, known already to be biodegradable, bioactive and able to be used as carriers for controlled release applications...

Preventive effect of regional radiotherapy with phosphorus-32 glass microspheres in hepatocellular carcinoma recurrence after hepatectomy

Wang, Xiao-Ming; Yin, Zhen-Yu; Yu, Ren-Xiang; Peng, You-Yuan; Liu, Ping-Guo; Wu, Guo-Yang
Fonte: The WJG Press and Baishideng Publicador: The WJG Press and Baishideng
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.36%
AIM: To evaluate the preventive effects of phosphorus-32 glass microspheres (P32-GMS) in the recurrence of massive hepatocellular carcinomas (HCCs) after tumor resection.

Porous-wall hollow glass microspheres as novel potential nanocarriers for biomedical applications

Li, Shuyi; Nguyen, Lynsa; Xiong, Hairong; Wang, Meiyao; Hu, Tom C.-C.; She, Jin-Xiong; Serkiz, Steven M.; Wicks, George G.; Dynan, William S.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.5%
Porous-wall hollow glass microspheres (PW-HGMs) are a novel form of glass material consisting of a 10 to 100 micron-diameter hollow central cavity surrounded by a 1 micron-thick silica shell. A tortuous network of nanometer-scale channels completely penetrates the shell. We show here that these channels promote size-dependent uptake and controlled release of biological molecules in the 3–8 nm range, including antibodies and a modified single-chain antibody variable fragment (scFv). In addition, a 6 nm (70 kDa) dextran can be used to gate the porous walls, facilitating controlled release of an internalized small interfering RNA. PW-HGMs remained in place after mouse intratumoral injection, suggesting a possible application for the delivery of anti-cancer drugs. The combination of a hollow central cavity that can carry soluble therapeutic agents with mesoporous walls for controlled release is a unique characteristic that distinguishes PW-HGMs from other glass materials for biomedical applications.

Hollow hydroxyapatite microspheres as a device for controlled delivery of proteins

Fu, Hailuo; Rahaman, Mohamed N.; Day, Delbert E.; Brown, Roger F.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.71%
Hollow hydroxyapatite (HA) microspheres were prepared by reacting solid microspheres of Li2O–CaO–B2O3 glass (106–150 μm) in K2HPO4 solution, and evaluated as a controlled delivery device for a model protein, bovine serum albumin (BSA). Reaction of the glass microspheres for 2 days in 0.02 M K2HPO4 solution (pH = 9) at 37°C resulted in the formation of biocompatible HA microspheres with a hollow core diameter equal to 0.6 the external diameter, high surface area (~100 m2/g), and a mesoporous shell wall (pore size ≈13 nm). After loading with a solution of BSA in phosphate-buffered saline (PBS) (5 mg BSA/ml), the release kinetics of BSA from the HA microspheres into a PBS medium were measured using a micro bicinchoninic acid (BCA) protein assay. Release of BSA initially increased linearly with time, but almost ceased after 24–48 h. Modification of the BSA release kinetics was achieved by modifying the microstructure of the as-prepared HA microspheres using a controlled heat treatment (1–24 h at 600–900°C). Sustained release of BSA was achieved over 7–14 days from HA microspheres heated for 5 h at 600°C. The amount of BSA released at a given time was dependent on the concentration of BSA initially loaded into the HA microspheres. These hollow HA microspheres could provide a novel inorganic device for controlled local delivery of proteins and drugs.

Temporary Balloon Occlusion of the Common Hepatic Artery for Yttrium-90 Glass Microspheres Administration in a Patient with Hepatocellular Cancer and Renal Insufficiency

Smith, Justin; Murthy, Ravi; Lahoti, Amit; Odisio, Bruno; Avritscher, Rony; Chasen, Beth; Mahvash, Armeen
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.21%
The most severe complication of yttrium-90 therapy is gastrointestinal ulceration caused by extrahepatic dispersion of microspheres. Standard pretreatment planning requires extensive angiographic evaluation of the hepatic circulation and embolization of hepatoenteric collaterals; however, in patients with severe renal insufficiency, this evaluation may lead to acute renal failure. In order to minimize iodinated contrast utilization in a patient with preexisting severe renal insufficiency, the authors describe the use of a balloon catheter for temporary occlusion of the common hepatic artery to induce transient redirection of flow of the hepatoenteric arteries towards the liver, in lieu of conventional coil embolization.

Mechanical load induced by glass microspheres releases angiogenic factors from neonatal rat ventricular myocytes cultures and causes arrhythmias

Barac, D Y; Reisner, Y; Silberman, M; Zeevi-Levin, N; Danon, A; Salomon, O; Shoham, M; Shilkrut, M; Kostin, S; Schaper, J; Binah, O
Fonte: John Wiley & Sons, Ltd Publicador: John Wiley & Sons, Ltd
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.95%
In the present study, we tested the hypothesis that similar to other mechanical loads, notably cyclic stretch (simulating pre-load), glass microspheres simulating afterload will stimulate the secretion of angiogenic factors. Hence, we employed glass microspheres (average diameter 15.7 μm, average mass 5.2 ng) as a new method for imposing mechanical load on neonatal rat ventricular myocytes (NRVM) in culture. The collagen-coated microspheres were spread over the cultures at an estimated density of 3000 microspheres/mm2, they adhered strongly to the myocytes, and acted as small weights carried by the cells during their contraction. NRVM were exposed to either glass microspheres or to cyclic stretch, and several key angiogenic factors were measured by RT-PCR. The major findings were: (1) In contrast to other mechanical loads, such as cyclic stretch, microspheres (at 24 hrs) did not cause hypertrophy. (2) Further, in contrast to cyclic stretch, glass microspheres did not affect Cx43 expression, or the conduction velocity measured by means of the Micro-Electrode-Array system. (3) At 24 hrs, glass microspheres caused arrhythmias, probably resulting from early afterdepolarizations. (4) Glass microspheres caused the release of angiogenic factors as indicated by an increase in mRNA levels of vascular endothelial growth factor (80%)...

Effect of phosphorus-32 glass microspheres on human hepatocellular carcinoma in nude mice

Zhang, Dong-Sheng; Liu, Lu; Jin, Li-Qiang; Wan, Mei-Ling; Li, Qun-Hui
Fonte: Baishideng Publishing Group Inc Publicador: Baishideng Publishing Group Inc
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.36%
AIM: To study the effects of phosphorus-32 glass microspheres (32P-GMS) on human hepatocellular carcinoma in nude mice.

Optical sensing using microspheres with different size and material

Miri, N.; Mohammadzaheri, M.
Fonte: Institute of Electrical and Electronics Engineers Publicador: Institute of Electrical and Electronics Engineers
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
Relevância na Pesquisa
36.54%
If light is trapped inside a microsphere and resonance occurs, the resonance modes known as whispering gallery modes could be employed for sensing the environment around the microsphere. The discrepancy of the resonance wavelengths for the microsphere surrounded by different media quantifies the sensing ability of the microsphere. However, the microsphere size and material are crucial factors on determining the minimum detection limit (DL) of the microsphere as a sensor. Therefore, through investigating an appropriate size and material for the microsphere, the sensing performance and efficiency of the microresonator increase. In this paper, through a comprehensive experimental study, different refractometric microspheres are presented and their optical properties are measured and analyzed. The microspheres, five different size polystyrene and one size silica microspheres, are coated with quantum dots (QDs) and the QDs are excited by an Nd:YAG laser. Then, the microspheres sensing ability is quantified when their surrounding environment is modified. According to the presented results, the microspheres’ DL, in direct proportion to the microsphere size, corresponds well to the theory. In addition, comparing the optical properties of the microspheres indicates the optimum size for the polymer microspheres to detect the environment. Furthermore...

Movable thin films with embedded high-index microspheres for super-resolution microscopy

Allen, Kenneth W.; Farahi, Navid; Li, Yangcheng; Limberopoulos, Nicholaos I.; Walker Jr., Dennis E.; Urbas, Augustine M.; Liberman, Vladimir; Astratov, Vasily N.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/08/2015
Relevância na Pesquisa
36.21%
Microsphere-assisted imaging emerged as a surprisingly simple way of achieving optical super-resolution imaging. In this work, we use movable PDMS thin films with embedded high-index barium titanate glass microspheres a sample scanning capability was developed, thus removing the main limitation of this technology based on its small field-of-view.; Comment: 8 pages, 5 figures, The article was published after peer-review in Annalen der Physik

Slipping friction of an optically and magnetically manipulated microsphere rolling at a glass-water interface

Agayan, Rodney R.; Smith, Ron G.; Kopelman, Raoul
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/03/2008
Relevância na Pesquisa
26.76%
The motion of submerged magnetic microspheres rolling at a glass-water interface has been studied using magnetic rotation and optical tweezers combined with bright-field microscopy particle tracking techniques. Individual microspheres of varying surface roughness were magnetically rotated both in and out of an optical trap to induce rolling, along either plain glass cover slides or glass cover slides functionalized with polyethylene glycol. It has been observed that the manipulated microspheres exhibited nonlinear dynamic rolling-while-slipping motion characterized by two motional regimes: At low rotational frequencies, the speed of microspheres free-rolling along the surface increased proportionately with magnetic rotation rate; however, a further increase in the rotation frequency beyond a certain threshold revealed a sharp transition to a motion in which the microspheres slipped with respect to the external magnetic field resulting in decreased rolling speeds. The effects of surface-microsphere interactions on the position of this threshold frequency are posed and investigated. Similar experiments with microspheres rolling while slipping in an optical trap showed congruent results.; Comment: submitted to Journal of Applied Physics...

Optical bistability in Er-Yb co-doped phosphate glass microspheres at room temperature

Ward, J. M.; O'Shea, D. G.; Shortt, B. J.; Chormaic, S. Nic
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 16/02/2007
Relevância na Pesquisa
46.36%
We experimentally demonstrate optical bistability in Er3+-Yb3+ phosphate glass microspheres at 295 K. Bistability is associated with both Er3+ fluorescence and lasing behavior, and chromatic switching. The chromatic switching results from an intrinsic mechanism exploiting the thermal coupling of closely-spaced energy levels, and occurs simultaneously with the intensity switching. A contrast ratio of 3.2 has been obtained for chromatic switching, and the intensity switching shows ratios of 2.4 for 550 nm and, 1.8 for the 660 nm fluorescence emissions, and 11 for the IR lasing at 1.5 um. Concurrent with these observations, we investigate a temperature dependent absorption of pump power which exhibits bistable behavior. The influences of the host matrix on lasing and fluorescence mechanisms are highlighted.; Comment: 22 pages, 6 figures

Vertical coupling of laser glass microspheres to buried silicon nitride ellipses and waveguides

Navarro-Urrios, Daniel; Ramirez, Joan Manel; Capuj, Nestor E.; Berencen, Yonder; Garrido, Blas; Tredicucci, Alessandro
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/06/2015
Relevância na Pesquisa
36.21%
We demonstrate the integration of Nd3+ doped Barium-Titanium-Silicate microsphere lasers with a Silicon Nitride photonic platform. Devices with two different geometrical configurations for extracting the laser light to buried waveguides have been fabricated and characterized. The first configuration relies on a standard coupling scheme, where the microspheres are placed over strip waveguides. The second is based on a buried elliptical geometry whose working principle is that of an elliptical mirror. In the latter case, the input of a strip waveguide is placed on one focus of the ellipse, while a lasing microsphere is placed on top of the other focus. The fabricated elliptical geometry (ellipticity=0.9) presents a light collecting capacity that is 50% greater than that of the standard waveguide coupling configuration and could be further improved by increasing the ellipticity. Moreover, since the dimensions of the spheres are much smaller than those of the ellipses, surface planarization is not required. On the contrary, we show that the absence of a planarization step strongly damages the microsphere lasing performance in the standard configuration.; Comment: 10 pages, 4 figures

Thermo-Optical Tuning of Whispering Gallery Modes in Er:Yb Doped Glass Microspheres to Arbitrary Probe Wavelengths

Watkins, Amy; Ward, Jonathan; Chormaic, Síle Nic
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/03/2012
Relevância na Pesquisa
36.15%
We present experimental results on an all-optical, thermally-assisted technique for broad range tuning of microsphere cavity resonance modes to arbitrary probe wavelengths. An Er:Yb co-doped phosphate glass (Schott IOG-2) microsphere is pumped at 978 nm via the supporting stem and the heat generated by absorption of the pump light expands the cavity and changes the refractive index. This is a robust tuning method that decouples the pump from the probe and allows fine tuning of the microsphere's whispering gallery modes. Pump/probe experiments were performed to demonstrate thermo-optical tuning to specific probe wavelengths, including the 5S1/2 F = 3 to 5P3/2 F' = 4 laser cooling transition of 85Rb. This is of particular interest for cavity QED-type experiments, while the broad tuning range achievable is useful for integrated photonic devices, including sensors and modulators.; Comment: 20 pages, 5 figures. To appear in Japanese Journal of Applied Physics

Aplicação de microesferas de vidro para avaliação da qualidade da superfície serrada da madeira de Eucalyptus grandis

Pigozzo, Fernando Jordão
Fonte: Universidade Federal de Lavras; Programa de Pós-Graduação em Ciência e Tecnologia da Madeira; UFLA; brasil; Departamento de Ciências Florestais Publicador: Universidade Federal de Lavras; Programa de Pós-Graduação em Ciência e Tecnologia da Madeira; UFLA; brasil; Departamento de Ciências Florestais
Tipo: Dissertação
Publicado em 17/12/2015 POR
Relevância na Pesquisa
46.61%
The use of machinery and software is growing in sawmills in order to increase the sawing yield. These measures also seek to improve the quality of sawn timber, given that warping, size variation and defects in the surfaces of the sawn pieces increase losses during finishing operations. Little is discussed in the literature concerning the surface quality of lumber. This occurs due to the shortage of evaluation methods. Therefore, the main objective of this study was to evaluate the quality of the sawn surface of Eucalyptus grandis lumber, after log sorting, defect analysis of the sawn pieces and yield calculation. For this, logs were sorted into four diameter classes. We evaluated their tapers, flattening and end checks. The sawing method was planned by Maxitoras® software - Optimber, and was compared with the actual yield. The quality of the sawn timber was assessed by measuring warping and size variation, as well as evaluating their surfaces by applying glass microspheres, based on the E-965 (ASTM, 1996) method. We concluded that: i) the shape of the logs was considered acceptable, according to the usual classification methods, however, the end check values were higher than the values found in literature; ii) the warping of sawn pieces was considered of high intensity...