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1.
Comput Biol Med ; 178: 108694, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38870728

RESUMO

Telemedicine is an emerging development in the healthcare domain, where the Internet of Things (IoT) fiber optics technology assists telemedicine applications to improve overall digital healthcare performances for society. Telemedicine applications are bowel disease monitoring based on fiber optics laser endoscopy, gastrointestinal disease fiber optics lights, remote doctor-patient communication, and remote surgeries. However, many existing systems are not effective and their approaches based on deep reinforcement learning have not obtained optimal results. This paper presents the fiber optics IoT healthcare system based on deep reinforcement learning combinatorial constraint scheduling for hybrid telemedicine applications. In the proposed system, we propose the adaptive security deep q-learning network (ASDQN) algorithm methodology to execute all telemedicine applications under their given quality of services (deadline, latency, security, and resources) constraints. For the problem solution, we have exploited different fiber optics endoscopy datasets with images, video, and numeric data for telemedicine applications. The objective is to minimize the overall latency of telemedicine applications (e.g., local, communication, and edge nodes) and maximize the overall rewards during offloading and scheduling on different nodes. The simulation results show that ASDQN outperforms all telemedicine applications with their QoS and objectives compared to existing state action reward state (SARSA) and deep q-learning network (DQN) policy during execution and scheduling on different nodes.


Assuntos
Aprendizado Profundo , Internet das Coisas , Telemedicina , Humanos , Tecnologia de Fibra Óptica , Algoritmos
2.
Water Res ; 250: 121069, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38150859

RESUMO

Wastewater discharge from outfall pipes can significantly impact river water quality and aquatic ecosystems. Effective outfall monitoring is critical for controlling pollution and protecting public health. This study demonstrates a novel distributed acoustic sensing (DAS) approach for detecting wastewater discharge events from outfall pipes located along rivers. Controlled field experiments were conducted in an industrial park river to systematically evaluate DAS performance. DAS detects vibrational signals imparted to suspended fiber-optic cables by turbulent wastewater flows, predominantly within 10-30 Hz, enabling continuous monitoring along entire river lengths. Vibrational power analysis locates outfalls with meter-level accuracy, while time-frequency techniques discern discharge timing and characteristics. Cable type and outfall-fiber separation influence on detection capability was assessed. Thermoplastic-jacketed tight buffer cables optimized detection through enhanced vibrational coupling. Vibrational energy decreased exponentially with separation, highlighting benefits of proximal deployment for sensitivity. However, detection range scales with discharge flow rate. Frequency centroid proved a robust feature with potential for automated discharge identification. Overall, DAS enables high spatiotemporal resolution monitoring to pinpoint concealed outfalls minimally invasively. This positions DAS as a promising tool supporting improved water governance through early pollution warnings and rapid source localization via outfall vibrational signatures emanating across river networks.


Assuntos
Ecossistema , Águas Residuárias , Rios , Monitoramento Ambiental , Acústica
3.
Sensors (Basel) ; 22(11)2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35684865

RESUMO

Observations from Raman backscatter-based Fiber-Optic Distributed Sensing (FODS) require reference sections of the fiber-optic cable sensor of known temperature to translate the primary measured intensities of Stokes and anti-Stokes photons to the secondary desired temperature signal, which also commonly forms the basis for other derived quantities. Here, we present the design and the results from laboratory and field evaluations of a novel Solid-Phase Bath (SoPhaB) using ultrafine copper instead of the traditional mechanically stirred liquid-phase water bath. This novel type is suitable for all FODS applications in geosciences and industry when high accuracy and precision are needed. The SoPhaB fully encloses the fiber-optic cable which is coiled around the inner core and surrounded by tightly interlocking parts with a total weight of 22 kg. The SoPhaB is thermoelectrically heated and/or cooled using Peltier elements to control the copper body temperature within ±0.04 K using commercially available electronic components. It features two built-in reference platinum wire thermometers which can be connected to the distributed temperature sensing instrument and/or external measurement and logging devices. The SoPhaB is enclosed in an insulated carrying case, which limits the heat loss to or gains from the outside environment and allows for mobile applications. For thermally stationary outside conditions the measured spatial temperature differences across SoPhaB parts touching the fiber-optic cable are <0.05 K even for stark contrasting temperatures of ΔT> 40 K between the SoPhaB's setpoint and outside conditions. The uniform, stationary known temperature of the SoPhaB allows for substantially shorter sections of the fiber-optic cable sensors of less than <5 bins at spatial measurement resolution to achieve an even much reduced calibration bias and spatiotemporal uncertainty compared to traditional water baths. Field evaluations include deployments in contrasting environments including the Arctic polar night as well as peak summertime conditions to showcase the wide range of the SoPhaB's applicability.

4.
J Biomed Opt ; 26(12)2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34935315

RESUMO

SIGNIFICANCE: Current methods for analyzing pathological muscle tissue are time consuming and rarely quantitative, and they involve invasive biopsies. Faster and less invasive diagnosis of muscle disease may be achievable using marker-free in vivo optical sensing methods. AIM: It was speculated that changes in the biochemical composition and structure of muscle associated with pathology could be measured quantitatively using visible wavelength optical spectroscopy techniques enabling automated classification. APPROACH: A fiber-optic autofluorescence (AF) and diffuse reflectance (DR) spectroscopy device was manufactured. The device and data processing techniques based on principal component analysis were validated using in situ measurements on healthy skeletal and cardiac muscle. These methods were then applied to two mouse models of genetic muscle disease: a type 1 neurofibromatosis (NF1) limb-mesenchyme knockout (Nf1Prx1 - / - ) and a muscular dystrophy mouse (mdx). RESULTS: Healthy skeletal and cardiac muscle specimens were separable using AF and DR with receiver operator curve areas (ROC-AUC) of >0.79. AF and DR analyses showed optically separable changes in Nf1Prx1 - / - quadriceps muscle (ROC-AUC >0.97) with no differences detected in the heart (ROC-AUC <0.67), which does not undergo gene deletion in this model. Changes in AF spectra in mdx muscle were seen between the 3 week and 10 week time points (ROC-AUC = 0.96) and were not seen in the wild-type controls (ROC-AUC = 0.58). CONCLUSION: These findings support the utility of in vivo fiber-optic AF and DR spectroscopy for the assessment of muscle tissue. This report highlights that there is considerable scope to develop this marker-free optical technology for preclinical muscle research and for diagnostic assessment of clinical myopathies and dystrophies.


Assuntos
Tecnologia de Fibra Óptica , Músculos , Animais , Camundongos , Camundongos Endogâmicos mdx , Análise de Componente Principal , Análise Espectral
5.
Front Robot AI ; 7: 513004, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33501300

RESUMO

This paper demonstrates how tactile and proximity sensing can be used to perform automatic mechanical fractures detection (surface cracks). For this purpose, a custom-designed integrated tactile and proximity sensor has been implemented. With the help of fiber optics, the sensor measures the deformation of its body, when interacting with the physical environment, and the distance to the environment's objects. This sensor slides across different surfaces and records data which are then analyzed to detect and classify fractures and other mechanical features. The proposed method implements machine learning techniques (handcrafted features, and state of the art classification algorithms). An average crack detection accuracy of ~94% and width classification accuracy of ~80% is achieved. Kruskal-Wallis results (p < 0.001) indicate statistically significant differences among results obtained when analysing only integrated deformation measurements, only proximity measurements and both deformation and proximity data. A real-time classification method has been implemented for online classification of explored surfaces. In contrast to previous techniques, which mainly rely on visual modality, the proposed approach based on optical fibers might be more suitable for operation in extreme environments (such as nuclear facilities) where radiation may damage electronic components of commonly employed sensing devices, such as standard force sensors based on strain gauges and video cameras.

6.
Funct Imaging Model Heart ; 11504: 168-176, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31245795

RESUMO

Clinical approaches for quantification of atrial fibrosis are currently based on digital image processing of magnetic resonance images. Here, we introduce and evaluate a comprehensive framework based on convolutional neural networks for quantifying atrial fibrosis from images acquired with catheterized fiber-optics confocal microscopy (FCM). FCM images in three regions of the atria were acquired in the beating heart in situ in an established transgenic animal model of atrial fibrosis. Fibrosis in the imaged regions was histologically assessed in excised tissue. FCM images and their corresponding histologically-assessed fibrosis levels were used for training of a convolutional neural network. We evaluated the utility and performance of the convolutional neural networks by varying parameters including image dimension and training batch size. In general, we observed that the root-mean square error (RMSE) of the predicted fibrosis was decreased with increasing image dimension. We achieved a RMSE of 2.6% and a Pearson correlation coefficient of 0.953 when applying a network trained on images with a dimension of 400 × 400 pixels and a batch size of 128 to our test image set. The findings indicate feasibility of our approach for fibrosis quantification from images acquired with catheterized FCM using convolutional neural networks. We suggest that the developed framework will facilitate translation of catheterized FCM into a clinical approach that complements current approaches for quantification of atrial fibrosis.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31236288

RESUMO

PURPOSE: To analyze endoscopic vitreoretinal surgery principles, applications, challenges and potential technological advances. BACKGROUND: Microendoscopic imaging permits vitreoretinal surgery for tissues that are not visible using operating microscopy ophthalmoscopy. Evolving instrumentation may overcome some limitations of current endoscopic technology. ANALYSIS: Transfer of the fine detail in endoscopic vitreoretinal images to extraocular video cameras is constrained currently by the caliber limitations of intraocular probes in ophthalmic surgery. Gradient index and Hopkins rod lenses provide high resolution ophthalmoscopy but restrict surgical manipulation. Fiberoptic coherent image guides offer surgical maneuverability but reduce imaging resolution. Coaxial endoscopic illumination can highlight delicate vitreoretinal structures difficult to image in chandelier or endoilluminator diffuse, side-scattered lighting. Microendoscopy's ultra-high magnification video monitor images can reveal microscopic tissue details blurred partly by ocular media aberrations in contemporary surgical microscope ophthalmoscopy, thereby providing a lower resolution, invasive alternative to confocal fundus imaging. Endoscopic surgery is particularly useful when ocular media opacities or small pupils restrict or prevent transpupillary ophthalmoscopy. It has a growing spectrum of surgical uses that include the management of proliferative vitreoretinopathy and epiretinal membranes as well as the implantation of posterior chamber intraocular lenses and electrode arrays for intraretinal stimulation in retinitis pigmentosa. Microendoscopy's range of applications will continue to grow with technological developments that include video microchip sensors, stereoscopic visualization, chromovitrectomy, digital image enhancement and operating room heads-up displays. CONCLUSION: Microendoscopy is a robust platform for vitreoretinal surgery. Continuing clinical and technological innovation will help integrate it into the modern ophthalmic operating room of interconnected surgical microscopy, microendoscopy, vitrectomy machine and heads-up display instrumentation.

8.
J Biomed Opt ; 23(7): 1-10, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29981224

RESUMO

While there are a plethora of in vivo fiber-optic spectroscopic techniques that have demonstrated the ability to detect a number of diseases in research trials with highly trained personnel familiar with the operation of experimental optical technologies, very few techniques show the same level of success in large multicenter trials. To meet the stringent requirements for a viable optical spectroscopy system to be used in a clinical setting, we developed components including an automated calibration tool, optical contact sensor for signal acquisition, and a methodology for real-time in vivo probe calibration correction. The end result is a state-of-the-art medical device that can be realistically used by a physician with spectroscopic fiber-optic probes. We show how the features of this system allow it to have excellent stability measuring two scattering phantoms in a clinical setting by clinical staff with ∼0.5 % standard deviation over 25 unique measurements on different days. In addition, we show the systems' ability to overcome many technical obstacles that spectroscopy applications often face such as speckle noise and user variability. While this system has been designed and optimized for our specific application, the system and design concepts are applicable to most in vivo fiber-optic-based spectroscopic techniques.


Assuntos
Fibras Ópticas , Imagem Óptica/instrumentação , Análise Espectral/instrumentação , Algoritmos , Humanos , Processamento de Imagem Assistida por Computador , Mucosa Intestinal/diagnóstico por imagem , Imagens de Fantasmas , Reto/diagnóstico por imagem
9.
Sensors (Basel) ; 17(9)2017 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-28925937

RESUMO

A rapid and reproducible fiber-optic immunosensor for Escherichia coli O157:H7 (E. coli O157:H7) was described. The biosensor consisted of a flow cell, an optical fiber with a thin Ni layer, and a PC linked fluorometer. First, the samples with E. coli O157:H7 were incubated with magnetic beads coated with anti-E. coli O157:H7 antibodies and anti-E. coli O157:H7 antibodies labeled cyanine 5 (Cy5) to make sandwich complexes. Then the Cy5-(E. coli O157:H7)-beads were injected into a flow cell and pulled to the magnetized Ni layer on the optical fiber set in the flow cell. An excitation light (λ = 635 nm) was used to illuminate the optical fiber, and the Cy5 florescent molecules facing the optical fiber were exposed to an evanescent wave from the optical fiber. The 670 nm fluorescent light was measured using a photodiode. Finally, the magnetic intensity of the Ni layer was removed and the Cy5-E. coli O157:H7-beads were washed out for the next immunoassay. E. coli O157:H7, diluted with phosphate buffer (PB), was measured from 1 × 105 to 1 × 107 cells/mL. The total time required for an assay was less than 15 min (except for the pretreatment process) and repeating immunoassay on one optical fiber was made possible.


Assuntos
Separação Imunomagnética , Técnicas Biossensoriais , Escherichia coli O157 , Imunoensaio , Fibras Ópticas
10.
Otolaryngol Clin North Am ; 50(3): 505-519, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28389019

RESUMO

Rhinoscopy became a formal field of study in the mid-nineteenth century as improvements in nasal specula were made and the potent vasoconstrictive effects of cocaine on the intranasal tissues were discovered. Since then, a multitude of advances in visualization and illumination have been made. The advent of the Storz-Hopkins endoscope in the mid-twentieth century represents a culmination of efforts spanning nearly 2 centuries, and illumination has evolved concomitantly. The future of endoscopic sinus surgery may integrate developing technologies, such as 3-dimensional endoscopy, augmented reality navigation systems, and robotic endoscope holders.


Assuntos
Endoscopia/história , Endoscopia/instrumentação , Seios Paranasais/cirurgia , Base do Crânio/cirurgia , Endoscopia/tendências , Técnicas Histológicas , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Imageamento Tridimensional , Iluminação , Procedimentos Cirúrgicos Robóticos
11.
Photoacoustics ; 5: 1-9, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28239552

RESUMO

We report on a novel imaging system for large depth of field photoacoustic scanning macroscopy. Instead of commonly used piezoelectric transducers, fiber-optic based ultrasound detection is applied. The optical fibers are shaped into rings and mainly receive ultrasonic signals stemming from the ring symmetry axes. Four concentric fiber-optic rings with varying diameters are used in order to increase the image quality. Imaging artifacts, originating from the off-axis sensitivity of the rings, are reduced by coherence weighting. We discuss the working principle of the system and present experimental results on tissue mimicking phantoms. The lateral resolution is estimated to be below 200 µm at a depth of 1.5 cm and below 230 µm at a depth of 4.5 cm. The minimum detectable pressure is in the order of 3 Pa. The introduced method has the potential to provide larger imaging depths than acoustic resolution photoacoustic microscopy and an imaging resolution similar to that of photoacoustic computed tomography.

12.
Neuroscience ; 338: 248-271, 2016 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-27702648

RESUMO

We have witnessed an accelerated growth of photonics technologies in recent years to enable not only monitoring the activity of specific neurons, while animals are performing certain types of behavior, but also testing whether specific cells, circuits, and regions are sufficient or necessary for initiating, maintaining, or altering this or that behavior. Compared to other sensory systems, however, such as the visual or olfactory system, photonics applications in pain research are only beginning to emerge. One reason pain studies have lagged behind is that many of the techniques originally developed cannot be directly implemented to study key relay sites within pain pathways, such as the skin, dorsal root ganglia, spinal cord, and brainstem. This is due, in part, to difficulties in accessing these structures with light. Here we review a number of recent advances in design and delivery of light-sensitive molecular probes (sensors and actuators) into pain relay circuits to help decipher their structural and functional organization. We then discuss several challenges that have hampered hardware access to specific structures including light scattering, tissue movement and geometries. We review a number of strategies to circumvent these challenges, by delivering light into, and collecting it from the different key sites to unravel how nociceptive signals are encoded at each level of the neuraxis. We conclude with an outlook on novel imaging modalities for label-free chemical detection and opportunities for multimodal interrogation in vivo. While many challenges remain, these advances offer unprecedented opportunities to bridge cellular approaches with context-relevant behavioral testing, an essential step toward improving translation of basic research findings into clinical applications.


Assuntos
Imagem Óptica , Dor/fisiopatologia , Animais , Humanos , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Imagem Óptica/instrumentação , Imagem Óptica/métodos , Optogenética/instrumentação , Optogenética/métodos , Dor/diagnóstico por imagem
13.
Annu Rev Anal Chem (Palo Alto Calif) ; 9(1): 45-68, 2016 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-27070183

RESUMO

Infrared spectroscopy in the 3-20 µm spectral window has evolved from a routine laboratory technique into a state-of-the-art spectroscopy and sensing tool by benefitting from recent progress in increasingly sophisticated spectra acquisition techniques and advanced materials for generating, guiding, and detecting mid-infrared (MIR) radiation. Today, MIR spectroscopy provides molecular information with trace to ultratrace sensitivity, fast data acquisition rates, and high spectral resolution catering to demanding applications in bioanalytics, for example, and to improved routine analysis. In addition to advances in miniaturized device technology without sacrificing analytical performance, selected innovative applications for MIR spectroscopy ranging from process analysis to biotechnology and medical diagnostics are highlighted in this review.

14.
Biotechnol Bioeng ; 112(6): 1210-9, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25765286

RESUMO

The use of microfluidics platforms combined with the optimal optical properties of gold nanoparticles has found plenty of application in molecular biosensing. This paper describes a bio-microfluidic platform coupled to a non-cross-linking colorimetric gold nanoprobe assay to detect a single nucleotide polymorphism associated with increased risk of obesity fat-mass and obesity-associated (FTO) rs9939609 (Carlos et al., 2014). The system enabled significant discrimination between positive and negative assays using a target DNA concentration of 5 ng/µL below the limit of detection of the conventionally used microplate reader (i.e., 15 ng/µL) with 10 times lower solution volume (i.e., 3 µL). A set of optimization of our previously reported bio-microfluidic platform (Bernacka-Wojcik et al., 2013) resulted in a 160% improvement of colorimetric analysis results. Incorporation of planar microlenses increased 6 times signal-to-loss ratio reaching the output optical fiber improving by 34% the colorimetric analysis of gold nanoparticles, while the implementation of an optoelectronic acquisition system yielded increased accuracy and reduced noise. The microfluidic chip was also integrated with a miniature fiber spectrometer to analyze the assays' colorimetric changes and also the LEDs transmission spectra when illuminating through various solutions. Furthermore, by coupling an optical microscope to a digital camera with a long exposure time (30 s), we could visualise the different scatter intensities of gold nanoparticles within channels following salt addition. These intensities correlate well to the expected difference in aggregation between FTO positive (none to small aggregates) and negative samples (large aggregates).


Assuntos
Técnicas Biossensoriais/métodos , Sondas de DNA , Ouro , Microfluídica/métodos , Nanotecnologia/métodos , Polimorfismo de Nucleotídeo Único , Colorimetria/métodos , Predisposição Genética para Doença , Humanos , Obesidade/genética , Imagem Óptica/métodos , Análise Espectral/métodos
15.
Front Physiol ; 5: 367, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25309455

RESUMO

Fiber-optics confocal microscopy (FCM) is an emerging imaging technology with various applications in basic research and clinical diagnosis. FCM allows for real-time in situ microscopy of tissue at sub-cellular scale. Recently FCM has been investigated for cardiac imaging, in particular, for discrimination of cardiac tissue during pediatric open-heart surgery. FCM relies on fluorescent dyes. The current clinical approach of dye delivery is based on systemic injection, which is associated with high dye consumption, and adverse clinical events. In this study, we investigated approaches for local dye delivery during FCM imaging based on dye carriers attached to the imaging probe. Using three-dimensional confocal microscopy, automated bench tests, and FCM imaging we quantitatively characterized dye release of carriers composed of open-pore foam only and foam loaded with agarose hydrogel. In addition, we compared local dye delivery with a model of systemic dye delivery in the isolated perfused rodent heart. We measured the signal-to-noise ratio (SNR) of images acquired in various regions of the heart. Our evaluations showed that foam-agarose dye carriers exhibited a prolonged dye release vs. foam-only carriers. Foam-agarose dye carriers allowed reliable imaging of 5-9 lines, which is comparable to 4-8 min of continuous dye release. Our study in the living heart revealed that the SNR of FCM images using local and systemic dye delivery is not different. However, we observed differences in the imaged tissue microstructure with the two approaches. Structural features characteristic of microvasculature were solely observed for systemic dye delivery. Our findings suggest that local dye delivery approach for FCM imaging constitutes an important alternative to systemic dye delivery. We suggest that the approach for local dye delivery will facilitate clinical translation of FCM, for instance, for FCM imaging during pediatric heart surgery.

16.
J Clin Anesth ; 26(6): 480-4, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25204508

RESUMO

STUDY OBJECTIVES: To determine, by fiberoptic endoscope, malpositioning of the Laryngeal Mask Airway (LMA) and other extraglottic devices. DESIGN: Prospective study. SETTING: University-affiliated medical center. PATIENTS: 60 adult, ASA physical status 1 and 2 patients, aged 20 - 60 years, scheduled to undergo ophthalmic procedures with general anesthesia during controlled ventilation via LMA (Laryseal). MEASUREMENTS: Adequacy of ventilation was determined by the absence of audible leak and appropriate capnograph trace. Fiberoptic assessment and imaging of LMA position were done after proper insertion of the LMA and after one hour of positive pressure ventilation (PPV). Assessment included position of the epiglottis, glottis, and cuff. MAIN RESULTS: The epiglottis was visible in 50 patients (83.3%). Vocal cords were visible in 58 patients at the time of insertion, and in 52 patients after one hour of PPV (P = 0.047). The arytenoids were herniating through the mask aperture after one hour of PPV (P = 0.0132). The cuff position was less optimal after one hour of controlled ventilation (P = 0.032). CONCLUSION: LMA position may change spontaneously with time during PPV, especially when the LMA position is not optimum at the time of insertion. The LMA should be adequately inserted with all possible measures in cases with general anesthesia and PPV. Fiberoptic assessment of LMA position intraoperatively may be advantageous.


Assuntos
Migração de Corpo Estranho/etiologia , Máscaras Laríngeas , Respiração com Pressão Positiva/efeitos adversos , Adulto , Anestesia Geral/métodos , Feminino , Tecnologia de Fibra Óptica/métodos , Migração de Corpo Estranho/diagnóstico , Migração de Corpo Estranho/patologia , Glote/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Oftalmológicos , Estudos Prospectivos , Adulto Jovem
17.
Biosens Bioelectron ; 61: 280-4, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24906086

RESUMO

In this paper, we describe the concept of a novel implantable fiber-optic Turbidity Affinity Sensor (TAS) and report on the findings of its in-vitro performance for continuous glucose monitoring. The sensing mechanism of the TAS is based on glucose-specific changes in light scattering (turbidity) of a hydrogel suspension consisting of small particles made of crosslinked dextran (Sephadex G100), and a glucose- and mannose-specific binding protein - Concanavalin A (ConA). The binding of ConA to Sephadex particles results in a significant turbidity increase that is much greater than the turbidity contribution by the individual components. The turbidity of the TAS was measured by determining the intensity of light passing through the suspension enclosed within a small semi-permeable hollow fiber (OD: 220 µm, membrane thickness: 20 µm, molecular weight cut-off: 10 kDa) using fiber optics. The intensity of measured light of the TAS was proportional to the glucose concentration over the concentration range from 50mg/dL to 400mg/dL in PBS and whole blood at 37°C (R>0.96). The response time was approximately 4 min. The stability of the glucose response of the TAS decreased only slightly (by 20%) over an 8-day study period at 37°C. In conclusion, this study demonstrated proof-of-concept of the TAS for interstitial glucose monitoring. Due to the large signal amplitude of the turbidity change, and the lack of need for wavelength-specific emission and excitation filters, a very small, robust and compact TAS device with an extremely short optical pathlength could be feasibly designed and implemented for in-vivo glucose monitoring in people with diabetes.


Assuntos
Técnicas Biossensoriais/instrumentação , Glicemia/análise , Tecnologia de Fibra Óptica/instrumentação , Concanavalina A/química , Dextranos/química , Desenho de Equipamento , Glucose/análise , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Luz , Limite de Detecção , Próteses e Implantes , Espalhamento de Radiação
18.
J Cardiothorac Vasc Anesth ; 28(4): 870-2, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24656617

RESUMO

OBJECTIVE: 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. DESIGN: A single-center retrospective study. SETTING: Thoracic surgery in a medical university hospital. PARTICIPANTS & INTERVENTIONS: After institutional review board approval, 29 patients who underwent thoracic surgical procedures using video double-lumen tubes were included in the final retrospective analysis. MEASUREMENTS AND MAIN RESULTS: 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. CONCLUSION: 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.


Assuntos
Intubação Intratraqueal/instrumentação , Respiração Artificial/métodos , Procedimentos Cirúrgicos Torácicos , Gravação em Vídeo/instrumentação , Idoso , Broncoscopia/métodos , Desenho de Equipamento , Feminino , Tecnologia de Fibra Óptica , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
19.
Anal Chim Acta ; 811: 1-12, 2014 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-24456588

RESUMO

The fluorescence of antioxidant additives in lubricant oil was used as an indicator of oxidative stability of the oil. It was found that the decrease in fluorescence intensities of phenyl-α-napthylamine, its dimer, and another unidentified antioxidant coincide with the formation of decomposition products of the oil base stock. Simple kinetic models were developed that were capable of describing antioxidant reactions as a pseudo first-order processes. It is shown that fluorescence excitation emission matrix (EEM) spectroscopy coupled with an optical fiber probe can provide real-time assessment of the oxidative stability of the lubricant. Parallel factor (PARAFAC) analysis was used to correlate the component scores to the oil breakdown number.

20.
Cytometry A ; 85(4): 322-31, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24339248

RESUMO

A fiber-optic based flow cytometry platform was designed to build a portable and robust instrument for space applications. At the core of the Microflow1 is a unique fiber-optic flow cell fitted to a fluidic system and fiber coupled to the source and detection channels. A Microflow1 engineering unit was first tested and benchmarked against a commercial flow cytometer as a reference in a standard laboratory environment. Testing in parabolic flight campaigns was performed to establish Microflow1's performance in weightlessness, before operating the new platform on the International Space Station. Microflow1 had comparable performances to commercial systems, and operated remarkably and robustly in weightlessness (microgravity). Microflow1 supported immunophenotyping as well as microbead-based multiplexed cytokine assays in the space environment and independently of gravity levels. Results presented here provide evidence that this fiber-optic cytometer technology is inherently compatible with the space environment with negligible compromise to analytical performance.


Assuntos
Citometria de Fluxo/instrumentação , Citometria de Fluxo/métodos , Leucócitos/citologia , Voo Espacial , Ausência de Peso , Humanos
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