2011
Authors
Silva, JS; Castro, CC; Vicente, AA; Tafulo, P; Jorge, PAS; Martins, RC;
Publication
INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS
Abstract
Saccharomyces cerevisiae morphology is known to be dependent on the cell physiological state and environmental conditions. On their environment, wild yeasts tend to form complex colonies architectures, such as stress response and pseudohyphal filaments morphologies, far away from the ones found inside bioreactors, where the regular cell cycle is observed under controlled conditions (e.g. budding and flocculating colonies). In this work we explore the feasibility of using micro-fiber optics spectroscopy to classify Saccharomyces cerevisiae S288C colony structures in YPD media, under different growth conditions, such as: i) no alcohol; ii) 1 % (v/v) Ethanol; iii) 1 % (v/v) 1-butanol; iv) 1 % (v/v) Isopropanol; v) 1 % (v/v) Tert-Amyl alcohol (2 Methyl-2-butanol); vi) 0,2 % (v/v) 2-Furadehyde; vii) 5 % (w/v) 5 (Hydroxymethyl)-furfural; and viii) 1 % (w/v) (-)-Adenosine3', 5'cyclic monophosphate. The microscopy system includes a hyperspectral camera apparatus and a micro fiber (sustained by micro manipulator) optics system for spectroscopy. Results show that micro fiber optics system spectroscopy has the potential for yeasts metabolic state identification once the spectral signatures of colonies differs from each others. This technique associated with other physico-chemical information can benefit the creation of an information system capable of providing extremely detailed information about yeast metabolic state that will aid both scientists and engineers to study and develop new biotechnological products.
2011
Authors
Tillak, JB; Bernacka Wojcik, I; Barata, D; Jorge, PAS; Aguas, H; Oliva, AG;
Publication
INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS
Abstract
This paper evaluates various strategies proposed for single cell refractometry and spectroscopy using fiber optic sensors and microfluidic chips. Details concerning design, fabrication and characterization of the chips will be addressed. Preliminary results obtained with alternative on-chip configurations using combination of fiber Bragg gratings with mirrored single mode and multimode fibers will be presented indicating the possibility of performing simultaneous assessment of cellular refractive index and absorption properties.
2011
Authors
Zibaii, MI; Jorge, PAS; Frazao, O; Latifi, H;
Publication
INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS
Abstract
A single-mode non-adiabatic tapered optical fiber (NATOF) sensor was inserted into a Sagnac loop interferometer allowing tuning its sensitivity to refractive index (RI) by use of polarization control. By adjusting any polarization controllers inserted in the Sagnac loop interferometer, various cladding modes are selectively excited in each arm of the interferometric taper resulting into different phase changes for the clockwise and counterclockwise beams. By this method, sensitivity of the sensor for RI in the range from 1.3380 to 1.3510 was tuned between 876.24 RIU/nm to 1233.07 RIU/nm.
2011
Authors
Goncalves, LC; Gonzalez Aguilar, G; Baptista, JM; Jorge, PAS;
Publication
21ST INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS
Abstract
This work describes the implementation of an optical fiber interferometric system for differential thermal analysis. The system is based on a white light Mach-Zehnder configuration, with serrodyne phase modulation, to interrogate two identical fiber Bragg gratings (FBG) in a differential scheme. Operation and signal processing with low cost digital instrumentation developed in Labview environment enabled FBG temperature measurement with a +/- 0.012 degrees C resolution nearly matching the performance of standard hardware. Preliminary results were obtained, where mixed samples of acetone and methanol could be successfully identified, indicating the suitability of the system for high accuracy differential thermal analysis using low cost instrumentation.
2011
Authors
Jesus, C; Jorge, PAS; Baptista, JM; Frazao, O;
Publication
INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS
Abstract
A fiber optic FBG cladding modes based sensor, for simultaneous measurement of strain and temperature is presented. The FBG cladding modes are efficiently excited by the large core misalignment. This technique enables the possibility to readout simultaneously in reflection the cladding mode (lambda(cl)) and the core mode (lambda(co)). lambda(cl), lambda(co) depend on strain and temperature and show different sensibilities for each parameter, enabling their discrimination. The experimental result shows a good performance in terms of linearity and sensitivity.
2011
Authors
Jesus, C; Jorge, PAS; Baptista, JM; Frazao, O;
Publication
21ST INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS
Abstract
A novel fiber optic curvature sensor based on a core-offset single-mode fiber (SMF) and on a fiber Bragg grating (FBG) is presented. The FBG cladding modes are efficiently excited by the large core misalignment. The curvature of the beam can be obtained by the reflected power of the core mode and the recoupled cladding mode.
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