Optical Fibre-Enabled Photoswitching for Localised Activation of an Anti-Cancer Therapeutic Drug.

Local activation of an anti-cancer drug when and where needed can improve selectivity and reduce undesirable side effects. Photoswitchable drugs can be selectively switched between active and inactive states by illumination with light; however, the clinical development of these drugs has been restricted by the difficulty in delivering light deep into tissue where needed. Optical fibres have great potential for light delivery in vivo, but their use in facilitating photoswitching in anti-cancer compounds has not yet been explored. In this paper, a photoswitchable chemotherapeutic is switched using an optical fibre, and the cytotoxicity of each state is measured against HCT-116 colorectal cancer cells. The performance of optical-fibre-enabled photoswitching is characterised through its dose response. The UV-Vis spectra confirm light delivered by an optical fibre effectively enables photoswitching. The activated drug is shown to be twice as effective as the inactive drug in causing cancer cell death, characterised using an MTT assay and fluorescent microscopy. This is the first study in which a photoswitchable anti-cancer compound is switched using an optical fibre and demonstrates the feasibility of using optical fibres to activate photoswitchable drugs for potential future clinical applications.

A Photonic crystal fiber with large effective refractive index separation and low dispersion.

A photonic crystal fiber (PCF) structure with a ring-core and 5 well-ordered semiellipse air-holes has been creatively proposed. Through a comparison between the structures with a high refractive index (RI) ring-core and the structure without, it conclude that a PCF with a high RI ring-core can work better. Schott SF57 was elected as the substrate material of ring-core. This paper compares the effects of long-axis and short-axis changes on the PCF and selects the optimal solution. Especially TE0,1 mode's dispersion is maintained between 0 and 3 ps / (nm · km) ranging from 1.45 µm to 1.65 µm. This property can be used to generate a supercontinuum with 200 µm long zero dispersion wavelength (ZDM). In addition, Δneff reaches up to 10-3, which enables the near -degeneracy of the eigenmodes to be almost neglected. The proposed PCF structure will have great application value in the field of optical communications.

Algorithm for automated selection of application-specific fiber-optic reflectance probes.

Several optical techniques and fiber-optic probe systems have been designed to measure the optical properties of tissue. While a wide range of options is often beneficial, it poses a problem to investigators selecting which method to use for their biomedical application of interest. We present a methodology to optimally select a probe that matches the application requirements. Our method is based both on matching a probe's mean sampling depth with the optimal diagnostic depth of the clinical application and on choosing a probe whose interrogation depth and path length is the least sensitive to alterations in the target medium's optical properties. Satisfying these requirements ensures that the selected probe consistently assesses the relevant tissue volume with minimum variability. To aid in probe selection, we have developed a publicly available graphical user interface that takes the desired sampling depth and optical properties of the medium as its inputs and automatically ranks different techniques in their ability to robustly target the desired depth. Techniques investigated include single fiber spectroscopy, differential path length spectroscopy, polarization-gating, elastic light scattering spectroscopy, and diffuse reflectance. The software has been applied to biological case studies.

In vitro performance of different methods in detecting occlusal caries lesions.

UNLABELLED: Early caries detection is essential for the implementation of preventive, therapeutic and intervention strategies within general dental practice. OBJECTIVE: The aim of this study was to compare the in vitro performance of the International Caries Detection and Assessment System (ICDAS), digital photographs scored with ICDAS (ICDAS photographs), fibre-optic transillumination (FOTI), optical coherence tomography (OCT), SoproLife(®) camera and two implementations of quantitative light-induced fluorescence a commercial (QLF-Inspektor Research systems) and a custom (QLF-Custom) system, to detect early and intermediate occlusal lesions. METHODS: One hundred and twelve permanent extracted teeth were selected and assessed with each detection method. Histological validation was used as a gold standard. The detection methods were compared by means of sensitivity, specificity, areas under receiver operating characteristic (AUROC) curves for enamel and dentine levels and with the Spearman's rank correlation coefficient against histology. RESULTS: For any enamel or dentine caries detection, the AUROC curves ranged from 0.86 (OCT) to 0.98 (ICDAS and ICDAS photographs, SoproLife(®) camera) and at the dentine level from 0.83 (OCT) to 0.96 for FOTI. The correlations with histology ranged between 0.65 (OCT) and 0.88 (ICDAS and FOTI). Under in vitro conditions, the assessed detection methods showed excellent intra-examiner reproducibility. All the methods were strongly correlated with histology (p<0.01) except OCT which showed a moderate correlation (0.65). CONCLUSION: Even though all methods present similar performance in detecting occlusal caries lesions, visual inspection seems to be sufficient to be used in clinical practice for detection and assessment of lesion depth. Other methods may be useful in monitoring caries lesion behaviour.

Influence of wavelength-dependent-loss on dispersive wave in nonlinear optical fibers.

In this work, we study numerically the influence of wavelength-dependent loss on the generation of dispersive waves (DWs) in nonlinear fiber. This kind of loss can be obtained, for instance, by the acousto-optic effect in fiber optics. We show that this loss lowers DW frequency in an opposite way that the Raman effect does. Also, we see that the Raman effect does not change the DW frequency too much when wavelength-dependent loss is included. Finally, we show that the DW frequency is not practically affected by fiber length.

Lista de verificação de materiais ópticos de videocirugia: efetividade do instrumento / Checklist of optical materials of videosurgery: effectiveness of the instrument

Avaliar a efetividade do uso da lista de verificação como instrumento de checagem padronizada para verificar o funcionamento e a estrutura de ópticas e cabos de fibra óptica usados em videocirurgias e analisar se, ao implantar a lista de verificação, ocorreu redução no número de ópticas danificadas.....

Comparison of lidocaine and levobupivacaine in transnasal fiberoptic laryngoscopy.

BACKGROUND: The anatomy of the nasal passages, pharynx, and larynx and evaluation of mucous membranes and laryngeal function is well observed by transnasal fiberoptic laryngoscopy (TFL). In this procedure, to provide good local infiltrative analgesia, medication such as anesthetics is important for the otolaryngologist. The aim of this study was to evaluate the efficacy of lidocaine (L) spray, compared with levobupivacaine solution, used for local anesthetic in patients undergoing TFL for complete examination. METHODS: Sixty-two subjects (39 men and 23 women; mean age, 36 ± 7 years) were enrolled in the study. Patients were randomly classified into two groups as levobupivacaine hydroclorur (LB) and L groups. A standard flexible transnasal fiberoptic 4.2-mm-diameter laryngoscope was passed through the nasal cavity and into the aerodigestive tract. Patients were asked to evaluate the intensity of the pain they experienced during the TFL, using a visual analog scale (VAS) and Ramsay sedation scale. RESULTS: Demographic data were similar in both groups. There was no difference in VAS and Ramsay scores between both groups (p > 0.05). CONCLUSION: Our findings indicated that topical levobupivacaine seems to be an effective medication for anesthesia of the nasal mucosa and may be used to allow complete examinations involving TFL.

Flexible fiberoptic bronchoscopy--a bedside technique for neonatologists.

BACKGROUND: Flexible fiberoptic bronchoscopy (FFB) is an under-used technology in neonates, mostly performed by external consultants from either pulmonology or otolaryngology. Modern ultra-thin scopes offer the neonatologist new diagnostic and therapeutic opportunities at the bedside. OBJECTIVE: To describe the diagnostic value, therapeutic potential, and safety profile of FFB in neonates when performed by neonatologists as a bedside procedure. METHODS: This was a retrospective case series that included 19 term and preterm infants who underwent FFB in two Neonatal Intensive Care Units (NICU). RESULTS: Twenty-five procedures were performed for the following indications: suspected airway pathology (15); BAL (8), noisy breathing (4), aid to difficult endotracheal intubation (1), investigation for failure of weaning from ventilation (6), and evaluation of tracheotomy or endotracheal tube patency (5). Thirteen procedures had more than one indication. Airway pathology was observed in 15 of 25 (60%) procedures. Treatment of atelectasis was successful in 7 of 10 cases. BAL culture results influenced antibiotic therapy in 5 of 10 cases (50%). No procedure-related mortality occurred. One serious adverse event (1/25, 4%), namely bilateral pneumothorax occurred 1 h after FFB. CONCLUSIONS: FFB is a useful and safe procedure that belongs in the neonatologists' armamentarium.

Transport infrastructure surveillance and monitoring by electromagnetic sensing: the ISTIMES project.

The ISTIMES project, funded by the European Commission in the frame of a joint Call "ICT and Security" of the Seventh Framework Programme, is presented and preliminary research results are discussed. The main objective of the ISTIMES project is to design, assess and promote an Information and Communication Technologies (ICT)-based system, exploiting distributed and local sensors, for non-destructive electromagnetic monitoring of critical transport infrastructures. The integration of electromagnetic technologies with new ICT information and telecommunications systems enables remotely controlled monitoring and surveillance and real time data imaging of the critical transport infrastructures. The project exploits different non-invasive imaging technologies based on electromagnetic sensing (optic fiber sensors, Synthetic Aperture Radar satellite platform based, hyperspectral spectroscopy, Infrared thermography, Ground Penetrating Radar-, low-frequency geophysical techniques, Ground based systems for displacement monitoring). In this paper, we show the preliminary results arising from the GPR and infrared thermographic measurements carried out on the Musmeci bridge in Potenza, located in a highly seismic area of the Apennine chain (Southern Italy) and representing one of the test beds of the project.

[Research on DNA fluorescence capillary biosensor marked by Goldview].

Goldview marked DNA fluorescence capillary biosensor was studied in the present paper. Based on fluorescence capillary analysis (FCA), the DNA biosensor uses capillary as immobilization carrier and detection carrier of DNA probe. Probes (20-mer-ssDNA) were immobilized on the inner wall of capillary by poly-l-lysine, and DNA fluorescence capillary biosensor (DNA-FCB) was made. After being hybridized with complementary target DNA and dyed by Goldview, the target DNA was qualified or quantified by detecting the fluorescence density of the Goldview using F-4500 spectrofluorometer. The sample volume was 12 microL. The concentration of the target DNA showed good linearity with the fluorescence intensity in the range of 0. 4-4 micromol x L(-1) (2.4-24 mg x L(-1)) (y = 65.911x + 3.9944, r = 0.9989). The RSD was lower than 3.5%. The concentration detection limit of the target DNA was 0.39 micromol x L(-1) (2.2 mg x L(-1)). The DNA-FCB can be used to qualify or quantify the target DNA. It's advantages are simplicity of manipulation, thimbleful of sample and reagent volumes, repeated use of capillary, and the lowest test cost. By using DNA-FCB to qualify the target DNA, we can consumedly decrease the pollution of the environment.

Performance measurement of the scintillator with optical fiber detector for boron neutron capture therapy.

The thermal neutron flux can be easily measured in real time by using the scintillator with optical fiber (SOF) detector. However the irradiation damage under high-intensity neutron flux causes deterioration of the SOF detector due to radiation damage to the plastic scintillator in which (6)LiF is blended. After irradiating the SOF detector for 4 h (thermal neutron fluence is approximately 2.0 x 10(13)neutrons/cm(2)), the sensitivity of the SOF detector decreased by 3.0%. After irradiating the SOF detector for 2 months (thermal neutron fluence approximately 6.4 x 10(14)neutrons/cm(2)), the sensitivity was reduced to 42% of baseline. Supposing that the thermal neutron fluence is 2 x 10(12)neutrons/cm(2) on the surface of a patient in a BNCT treatment, the sensitivity of the SOF detector is reduced by approximately 0.3%. This report presents investigations on the deterioration of the SOF detector in irradiation experiments.

Emergence of self-organized long-period fiber gratings in supercontinuum-generating optical fibers.

A localized long-period fiber grating emerges in a silica optical fiber transmitting femtosecond pulse-induced supercontinuum. Simultaneously, a specific higher-order fiber cladding mode associated with the grating gains amplification at the expense of the fiber core mode. The grating has a period dependent on the dielectric structure of the fiber and is therefore classified as a self-organized structure.

Fiber-optic endomicroscopy system for high-resolution nonlinear imaging of biological tissue.

A flexible fiber-optic endomicroscopy system was developed for nonlinear optical imaging of biological samples. Double-clad fiber and photonic bandgap fiber were employed in the endomicroscope for femtosecond pulse delivery, dispersion compensation, nonlinear optical signals collection and fast beam scanning. Three-dimensional imaging of biological tissues based on second harmonic generation and two-photon excited fluorescence was performed with the endomicroscope. The depth-resolved imaging results strongly suggest the potential of this flexible fiber-optic microscope system for real-time assessment of both epithelial and stromal structures in luminal organs.