Use Of Optical Fibers Research Articles

Nanomaterial-based biosensors for detection of prostate specific antigen.

Screening serum for the presence of prostate specific antigen (PSA) belongs to the most common approach for the detection of prostate cancer. This review (with 156 refs.) addresses recent developments in PSA detection based on the use of various kinds of nanomaterials. It starts with an introduction into the field, the significance of testing for PSA, and on current limitations. A first main section treats electrochemical biosensors for PSA, with subsections on methods based on the use of gold electrodes, graphene or graphene-oxide, carbon nanotubes, hybrid nanoparticles, and other types of nanoparticles. It also covers electrochemical methods based on the enzyme-like activity of PSA, on DNA-, aptamer- and biofuel cell-based methods, and on the detection of PSA via its glycan part. The next main section covers optical biosensors, with subsections on methods making use of surface plasmon resonance (SPR), localized SPR and plasmonic ELISA-like schemes. This is followed by subsections on methods based on the use of fiber optics, fluorescence, chemiluminescence, Raman scattering and SERS, electrochemiluminescence and cantilever-based methods. The most sensitive biosensors are the electrochemical ones, with lowest limits of detection (down to attomolar concentrations), followed by mass cantilever sensing and electrochemilumenescent strategies. Optical biosensors show lower performance, but are still more sensitive compared to standard ELISA. The most commonly applied nanomaterials are metal and carbon-based ones and their hybrid composites used for different amplification strategies. The most attractive sensing schemes are summarized in a Table. The review ends with a section on conclusions and perspectives.

Multimodal brain imaging with magnetoencephalography: A method for measuring blood pressure and cardiorespiratory oscillations

Studies with magnetoencephalography (MEG) are still quite rarely combined simultaneously with methods that can provide a metabolic dimension to MEG investigations. In addition, continuous blood pressure measurements which comply with MEG compatibility requirements are lacking. For instance, by combining methods reflecting neurovascular status one could obtain more information on low frequency fluctuations that have recently gained increasing interest as a mediator of functional connectivity within brain networks. This paper presents a multimodal brain imaging setup, capable to non-invasively and continuously measure cerebral hemodynamic, cardiorespiratory and blood pressure oscillations simultaneously with MEG. In the setup, all methods apart from MEG rely on the use of fibre optics. In particular, we present a method for measuring of blood pressure and cardiorespiratory oscillations continuously with MEG. The potential of this type of multimodal setup for brain research is demonstrated by our preliminary studies on human, showing effects of mild hypercapnia, gathered simultaneously with the presented modalities.

Effect of Multiple Doses of Dexmedetomidine for Moderate Sedation Facilitating Intubation during Nasotracheal Fiberoptic Laryngoscope in Awake Patients-A Randomized Prospective Study

Background: Nasal fiberoptic intubation in fully conscious patients is the gold standard technique of choice in known difficult airway as cervical instability, limited mouth opening and any facial defects. The usage of an ideal sedation agent with a perfect dose or regimen securing stability of hemodynamic conditions and optimizing the intubating condition at the same time is an indispensable demand for awake fiberoptic intubation. Aim: To detect variant efficiency of different doses of dexmedetomidine used for conscious sedation facilitating intubation by using nasotracheal fiberoptic laryngoscope in awake patients. Methods: The study was performed in a prospective, blinded, randomized manner to compare the effect of different loading and maintenance doses of dexmedetomidine during awake fiberoptic intubation on 40 patients of both sexes aged between 20 and 60 years with ASA grade I or II enrolled for elective surgery. Patients randomly divided into two groups; 20 for each. All patients received 50 mcg Fentanyl and 2 mg Midazolam at premedication room, before transfer to operating room. Group I patients received I.V. Dexmedetomidine 1 mcg/kg as a bolus dose slowly over ten minutes then 0.7 mcg/kg/h as maintenance dose throughout the fiberoptic manipulation. Group II patients received I.V. Dexmedetomidine 0.7 mcg/kg as a bolus dose slowly over ten minutes then 0.2 mcg/kg/h as a maintenance dose throughout the technique. Primary outcomes were assessment of sedation level of each patient by Alertness and Sedation Scale (AA/S). Patient's reaction to insertion of tracheal tube that could be also assessed during Pre-oxygenation, both fiberscope placement and endotracheal placement (at 1, 2, 3, 4, 5 min interval) and if the patients were feeling comfort or distressing .This comfort scale for each patient was estimated by addition of seven comfort items at each time point, the total score was 35. Patient tolerance also was assessed on the basis of 5 point fiber optic index (FOI) score. Secondary outcomes were hemodynamic categories as heart rate, systolic blood pressure, diastolic blood pressure, mean blood pressure, oxygen saturation and end tidal capnography during Pre-oxygenation, both fiberoptic placement and endotracheal insertion ( at 1, 2, 3, 4, 5 min interval) and any side effects were also explored. Results: All patients in both groups underwent fiberoptic intubation with no differences statistically among two groups demographically, heart rate, systolic, diastolic and mean blood pressure. There were statistically differences among two groups as regard to SPO2, PACO2 and OAA/S scale only at 3, 4 and 5 min during endotracheal tube placement. No side effects were observed. Conclusion: We concluded that dexmedetomidine especially with loading 1 μg/kg and higher maintenance dose 0.7 μg/kg/h were more suitable for fiberoptic intubation with better patient tolerance, patient comfort, patient satisfaction, good sedation and preserved upper airway with spontaneous breathing.

The Molecular Bronchoscope: A Tool for Measurement of Spatially Dependent CO2 Concentrations in the Lungs.

Respiratory physicians use bronchoscopy for visual assessment of the lungs' topography and collecting tissue samples for external analysis. We propose a novel bronchoscope tool that would enable spatially dependent measurements of the functioning of the lungs by determining local concentrations of carbon dioxide, which will be produced by healthy parts of the lung at rates that are higher than from portions where gas exchange is impaired. The gas analyzer is based on a compact laser absorption spectrometer making use of fiber optics for delivery and return of low intensity diode laser radiation to and from the measurement chamber at the distal end of a flexible conduit. The appropriate optical wavelength was chosen such that light is selectively absorbed only by gaseous CO2. The optical absorption takes place over a short path (8.8 mm) within a rigid, 12 mm long, perforated probe tip. Wavelength modulation spectroscopy was adopted as the analytical technique to reduce the noise on the optical signal and yield measurements of relative CO2 concentration every 180 ms with a precision as low as 600 part-per-million by volume. The primary objective of such a device is to see if additional spatial information about the lungs functionality can be gathered, which will complement visual observation.

Migration to Broadband and Ubiquitous Environments by Using Fiber-Optic Technologies in Access/Home Areas

ABSTRACTThe recent dramatic advances in information and communication technologies have yielded new environments. However, adoption still differs area by area. To realize the future broadband environment that everyone can enjoy everywhere, several technical issues have to be resolved before network penetration becomes ubiquitous. One such key is the use of fiber optics for the home and mobile services. This article overviews initial observations drawn from numerical survey data gathered over the last decade in several countries/regions, and gives some example scenarios for network/service evolution. One result implies that implementing new/future services must consider the gross domestic product impact.

Technology Focus: Production Monitoring/Surveillance (March 2016)

Technology Focus Despite the market conditions during the last year, our industry continued to demonstrate further advances in the monitoring and surveillance field and to attest to the added value provided. General trends from past years are still being pursued to further our knowledge related to the issues seen as most important for production optimization and field management. Studies and methods were shared regarding unconventional development such as fracturing performance and analysis. New developments for multiphase-flow-metering evaluation and verification continue to be a leading topic. Additional studies were shared in understanding flow regimes in long horizontal wells using new methods and combined data gathering. Downhole solutions providing data in horizontal and difficult wellbore trajectories without intervention were further developed with tracers and other technology. New and novel methods for the use of fiber optics continue to come forth with advancements in strain and acoustic measurements that have been shown to add value. Challenges regarding the management of large data streams are still being discussed, although some interesting practical applications incorporating multiple data streams managed simultaneously in real-time scenarios were shared during the past year. Newer trends indicate further cooperation across the industry. Results from multiple collaboration efforts were released and discussed that involved partners from government agencies, operators, service providers, and various third parties working together to solve problems for the future. Case studies are now being presented for practical applications of advanced technology and optimization methodology that were considered only visions not that many years ago. It is very exciting for us to see the results from the efforts that have taken place over the past several years. Success cases for fieldwide implementation of real-time data gathering combined with work flows, modeling, and predictive analysis are becoming more prevalent. Subsurface monitoring applications relating to kick detection and managed-pressure drilling are gaining more attention as we also push the limits on the drilling side of the surveillance field. The technology initially developed for production monitoring may be forging the way for wide applications across oilfield operations. The following is a selection of articles to demonstrate the accomplishments shared by the exceptional peers who chose to publish their knowledge from the last year. Additional reading suggestions are also provided. JPT Recommended additional reading at OnePetro: www.onepetro.org. SPE 173452 Lessons Learned From Worldwide Deployments of Model-Based Real-Time Production-Optimization Solutions by Amol Bakshi, Chevron, et al. IPTC 17773 Real-Time Calculation of Fluid Level Using Dynamometer Card of Sucker-Rod-Pump Well by Yang Haitao, PetroChina, et al. SPE 172593 Combining Horizontal Production-Logging and Distributed- Temperature Interpretations To Diagnose Annular Flow in Slotted-Liner Completions by T. Ben Haoua, Schlumberger, et al.

Miniature ball-tip optical fibers for use in thulium fiber laser ablation of kidney stones.

Optical fibers, consisting of 240-μm-core trunk fibers with rounded, 450-μm-diameter ball tips, are currently used during Holmium:YAG laser lithotripsy to reduce mechanical damage to the inner lining of the ureteroscope working channel during fiber insertion and prolong ureteroscope lifetime. Similarly, this study tests a smaller, 100-μm-core fiber with 300-μm-diameter ball tip during thulium fiber laser (TFL) lithotripsy. TFL was operated at a wavelength of 1908 nm, with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times were measured, and ablation rates were calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to track ball tip degradation and determine number of procedures completed before need for replacement. A high speed camera also recorded the cavitation bubble dynamics during TFL lithotripsy. Additionally, saline irrigation rates and ureteroscope deflection were measured with and without the presence of TFL fiber. There was no statistical difference (P>0.05) between stone ablation rates for single-use ball tip fiber (1.3±0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3±0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3±0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged greater than four stone procedures before failure, defined by rapid decline in stone ablation rates. Mechanical damage at the front surface of the ball tip was the limiting factor in fiber lifetime. The small fiber diameter did not significantly impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and into the ureter without risk of instrument damage or tissue perforation, and without compromising stone ablation efficiency during TFL lithotripsy.

Combined Optogenetic and Chemogenetic Control of Neurons.

Optogenetics provides an array of elements for specific biophysical control, while designer chemogenetic receptors provide a minimally invasive method to control circuits in vivo by peripheral injection. We developed a strategy for selective regulation of activity in specific cells that integrates opto- and chemogenetic approaches, and thus allows manipulation of neuronal activity over a range of spatial and temporal scales in the same experimental animal. Light-sensing molecules (opsins) are activated by biologically produced light through luciferases upon peripheral injection of a small molecule substrate. Such luminescent opsins, luminopsins, allow conventional fiber optic use of optogenetic sensors, while at the same time providing chemogenetic access to the same sensors. We describe applications of this approach in cultured neurons in vitro, in brain slices ex vivo, and in awake and anesthetized animals in vivo.

In-situ formation compaction monitoring in deep reservoirs by use of fiber optics

Abstract. We have devised a new in situ monitoring method for the amount of stratified compaction in borehole drilled several hundred meters underground. This newly developed epoch-making monitoring system differs from conventional monitoring methods for land subsidence in that it is designed to continuously monitor the amounts of displacement in several intervals separately, using optical fibers fitted in the sensor assembly. This report presents results from a deep observation well. This is a continued report from the previous one on EISOLS 2010.

Polarization‐maintaining Fiber Optics

AbstractA stable measurement setup is fundamental for any successful measurement. A major cause of frustration and error is the need to continuously readjust optomechanical equipment because of continuous instabilities. The use of fiber optics has proven to increase both stability and convenience significantly when compared with standard free‐beam setups. These modular, complex and self‐contained setups also often increase laser safety and reduce the laser safety classification. The defined interface between a laser source and the more sensitive environment of the measurement setup provides the physical separation that enables a mechanical and thermal decoupling, suppressing mutually negative effects.

Application of laser-induced breakdown spectroscopy in carbon sequestration research and development

The success of carbon capture and storage (CCS) programme relies on the long-term isolation of CO2 from the atmosphere. Therefore, technologies concomitant to physical storage of CO2 such as reliable measurement, monitoring, and verification (MMV) techniques are needed to ensure that the integrity of the storage site is maintained. We propose the use of laser-induced breakdown spectroscopy (LIBS) analytical technique to detect carbon dioxide leaks to aid in the successful application of CCS. LIBS has a real-time monitoring capability and can be reliably used for the elemental and isotopic analysis of solid, liquid, and gas samples. The flexibility of probe design and use of fibre optics make it a suitable technique for real time measurements in harsh conditions and at hard-to-reach places. Proposed monitoring with LIBS includes terrestrial soil samples, water samples from monitoring wells or from different formations, air samples from monitoring wells or suspected leakage areas. This work details the laboratory scale experiments to measure carbon contents in rock, soil, aqueous, and air samples. The potential of the technology for measurements in high pressure high-temperature conditions will also be discussed.

A Retrospective Evaluation of the Use of Video-Capable Double-Lumen Endotracheal Tubes in Thoracic Surgery

The objective of this study was to evaluate whether the use of a video double-lumen tube reduced the need for fiberoptic bronchoscopy for (1) verification of initial tube placement and for (2) reverification of correct placement after repositioning for thoracotomy. A single-center retrospective study. Thoracic surgery in a medical university hospital. After institutional review board approval, 29 patients who underwent thoracic surgical procedures using video double-lumen tubes were included in the final retrospective analysis. For 27 (93.2%) patients, the use of fiberoptic bronchoscopy was not needed either for initial placement or for verification of correct video double-lumen tube placement upon final positioning of the patient. However, for two patients, fiberoptic bronchoscopy was needed: for (1) one patient with severe left mainstem bronchus distortion as a result of a large left upper lobe tumor, and (2) a second patient with secretions that were difficult to clear. This study demonstrates that the video double-lumen tube requires significantly less (6.8%) fiberoptic use for both initial placement and verification of final position, in stark contrast to standard practice in which bronchoscopy is always used to verify final positioning of the double-lumen tube. As opposed to intermittent bronchoscopy, the continuous visualization offered by an embedded camera may confer an added measure of safety.

Evaluation of the performance of high phosphorous with germanium codoped multimode optical fiber for use as a radiation sensor at low dose rates

We propose a GeO2–P2O5-codoped step index multimode (SIMM) fiber having a core diameter of around 50 μm with numerical aperture of around 0.21–0.22. The proposed SIMM fiber shows excellent linear radiation response behavior with sensitivity of around 0.69–0.97 dB/m/100 rad at a 505 nm wavelength within the dose rate range of 10–100 rad/h, as well as very low recovery at room temperature using a Co60 gamma radiation source. This enables its practical application in fiber optic personal dosimeters for measurement of low dose gamma radiation.

Comparison of Frequency Symmetric Signal Generation From a BPSK Input Using Fiber and Semiconductor-Based Nonlinear Elements

This letter compares two nonlinear media for simultaneous carrier recovery and generation of frequency symmetric signals from a 42.7-Gb/s nonreturn-to-zero binary phase-shift-keyed input by exploiting four-wave mixing in a semiconductor optical amplifier and a highly nonlinear optical fiber for use in a phase-sensitive amplifier.

Physicochemical and optical properties of glasses in the Ga4Ge21Se50-Sb2Se3 system

This paper reports on the results of an investigation into the concentration behavior of the glass-forming ability, heat resistance, glass transition temperature, density, refractive index, transparent spectral region, and impurity optical absorption of glasses in the Ga4Ge21Se50-Sb2Se3 system. The data obtained indicate that glasses in the Ga4Ge21Se50-Sb2Se3 system with a high Sb2Se3 content are of interest as materials for use in fiber optics.

Technology Focus: Production/Facilities (December 2009)

Technology Focus Reviewing papers to highlight in this year's feature, I was struck by the widespread embrace of novel technologies used at the macro and micro levels. This upsurge of acceptance of new approaches in the oil patch is long overdue and welcome. Nanotechnology and microelectromechanical systems are finding their way from the laboratory to practical applications. In addition, the growing use of fiber optics as the high-speed conduit to satisfy the burgeoning demand for real-time information in process management and for inspection, maintenance, and repair, is making inroads to improve sensor technology by harnessing unique physical properties of light in extremely hostile environments in which more-traditional methods have succumbed. The papers noted this month also foretell that we as an industry are more willing to look at old problems in new perspectives—using new materials, chemical agents, and techniques to solve tough problems that, just a few years ago, conventional wisdom considered impractical or unsolvable by the "throwing more iron at it" method. The new decade holds some exciting new prospects that will, once again, revitalize the industry and push the "oil peak" further out yet again. Production/Facilities additional reading available at OnePetro: www.onepetro.org SPE 123007 • "New Product for Inhibition of Calcium Carbonate Scale in Natural-Gas and Oil Facilities Based on Aloe Vera: Application in Venezuelan Oil Fields" by L.A. Castillo, PDVSA, et al. OTC 19937 • "Plastic Liners for Hydrocarbon Transport: A Qualified and Cost-Efficient Alternative to Corrosion-Resistant Alloys" by S.J. Hall, Technip, et al. SPE 120631 • "Determination of the Suitability of Reinforced Thermoplastic Pipe for Applications With Aromatic and Cyclo-Aliphatic Hydrocarbons" by B. Weller, Flexpipe Systems, et al. SPE 120837 • "A New Microbiologically-Influenced-Corrosion Control Strategy in Low-Velocity Gas-Gathering Pipelines" by C. Smith, SPE, ICTC, et al. SPE 123005 • "New Method for Extracting Oils and Greases From Produced Water Using Microwave Techniques" by R.H. Bezerril, Federal University of Rio Grande do Norte, et al.

Physicochemical and optical properties of glasses in the Ga4Ge21S50-Sb2S3 system

This paper reports on the results of an investigation into the influence of Sb2S3 dopants on the glass-forming ability, heat resistance, softening temperature, density, refractive index, transparent region, and impurity optical absorption of glasses of the composition 0.16GaS2 · 0.84GeS2. The data obtained indicate that glasses in the Ga4Ge21S50-Sb2S3 system with a high Sb2S3 content are of interest as materials for use in fiber optics.

Fabrication of Nickel Sealed Double-Coated Optical Fibers for Use as Optical Transmission Lines

The nickel sealed double-coated optical fiber is constructed from the double-coated optical fiber sealed with a nickel layer that is fabricated using electroless plating. The nickel sealed double-coated optical fiber exhibits good electrical conductivity, high mechanical strength, high resistance to moisture attack and microbending insensitivity. Moreover, the external damage protection, abrasion resistance, adhesion, toughness and stripping force of coatings fit the fiber requirement. As the nickel film thickness is 68 nm, the fiber has the excellent ability to sustain thermal loading. Nickel sealed double-coated optical fibers are superior to conventional double-coated optical fibers and hermetically coated optical fibers for use as optical transmission lines.

Offshore-Connectivity Solutions for the Oil and Gas Industry

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 117254, "Offshore Connectivity and Ultra-Long Tiebacks Solutions for Oil & Gas," by A. Lecroart, R. Michel, and J.P. Odier, Alcatel-Lucent Submarine Networks, originally prepared for the 2008 SPE Asia Pacific Oil and Gas Conference and Exhibition, Perth, Australia, 20-22 October. The paper has not been peer reviewed. The oil and gas industry is forced to go into deeper water further offshore to find new oil or gas. At the same time, the industry is placing more emphasis on integrated operations driven from onshore control centers. Highly reliable communications solutions are required to fulfill these objectives. Large bandwidth and low latency links between offshore facilities and the shore are essential for communications to all company personnel and contractors engaged in the offshore development areas. The full-length paper describes overall solutions to address these needs and reviews available technologies. Introduction Exploration and production of offshore fields is evolving and makes use of various modes of communication. Many oil companies are establishing operations centers where technical expertise is located. Telecommunications from the field to these centers is becoming critical, and solutions exist to make communication both efficient and dependable, with a choice of different technologies listed in Table 1 in the full-length paper. Dry/Dry Solutions The dry/dry solutions adapt the traditional shore-to-shore telecommunication application so that it can be used with different types of offshore assets such as a fixed platform or floating assets such as a tension-leg platform, a spar, or a floating production, storage, and offloading vessel (FPSO). One would prefer ring or loop architectures connecting each asset with its own spur by use of a branching unit (BU). The system is designed to allow the platforms to be independent and limits the number of risers per asset to one, compared to a simple daisy chain. For the last-mile connection, a dynamic riser is required to access floating assets, while a simple J-tube may be sufficient with shallower fixed structures. Another complexity may come from the use of fiber-optics (FOs) rotating joints because the latest generation of FPSOs tends to adopt a turret architecture, allowing the vessel to rotate freely. In most cases, studies are required to validate and qualify the riser design according to the requirements of the structure and the local weather conditions. A second approach is to equip an umbilical with fiber and allow the last-mile connection to take place subsea with a combination of wet-mate connectors and subsea manifold. In this case, a special cable termination is provided allowing remotely-operated-vehicle (ROV) handling of the wet-mate connector by use of a length of flexible hose. Both approaches are valid and will solve the last-mile issue adequately.

Fiberoptic Oral Intubation

Previous studies have indicated that fiberoptic orotracheal intubation (FOI) skills can be learned outside the operating room. The purpose of this study was to determine which of two educational interventions allows learners to gain greater capacity for performing the procedure. Respiratory therapists were randomly assigned to a low-fidelity or high-fidelity training model group. The low-fidelity group was guided by experts, on a nonanatomic model designed to refine fiberoptic manipulation skills. The high-fidelity group practiced their skills on a computerized virtual reality bronchoscopy simulator. After training, subjects performed two consecutive FOIs on healthy, anesthetized patients with predicted "easy" intubations. Each subject's FOI was evaluated by blinded examiners, using a validated global rating scale and checklist. Success and time were also measured. Data were analyzed using a two-way mixed design analysis of variance. There was no significant difference between the low-fidelity (n = 14) and high-fidelity (n = 14) model groups when compared with the global rating scale, checklist, time, and success at achieving tracheal intubation (all P = not significant). Second attempts in both groups were significantly better than first attempts (P < 0.001), and there was no interaction between "fidelity of training model" and "first versus second attempt" scores. There was no added benefit from training on a costly virtual reality model with respect to transfer of FOI skills to intraoperative patient care. Second attempts in both groups were significantly better than first attempts. Low-fidelity models for FOI training outside the operating room are an alternative for programs with budgetary constraints.