Nonlinearity measurement undergoing dispersion and loss.

Accurate knowledge of the nonlinear coefficient is extremely important to make reliable predictions about optical pulses propagating along waveguides. Nevertheless, determining this parameter when dispersion and loss are as important as nonlinear effects brings both theoretical and experimental challenges that have not yet been solved. A general method for measuring the nonlinear coefficient of waveguides under these demanding conditions is here derived and demonstrated experimentally in a kilometer-long standard silica fiber pumped close to 2 µm.

Recent Advances in Forward Brillouin Scattering: Sensor Applications.

In-fiber opto-mechanics based on forward Brillouin scattering has received increasing attention because it enables sensing the surrounding of the optical fiber. Optical fiber transverse acoustic resonances are sensitive to both the inner properties of the optical fiber and the external medium. A particularly efficient pump and probe technique-assisted by a fiber grating-can be exploited for the development of point sensors of only a few centimeters in length. When measuring the acoustic resonances, this technique provides the narrowest reported linewidths and a signal-to-noise ratio better than 40 dB. The longitudinal and transverse acoustic velocities-normalized with the fiber radius-can be determined with a relative error lower than 10-4, exploiting the derivation of accurate asymptotic expressions for the resonant frequencies. Using this technique, the Poisson's ratio of an optical fiber and its temperature dependence have been measured, reducing the relative error by a factor of 100 with respect to previously reported values. Using a single-point sensor, discriminative measurements of strain and temperature can be performed, achieving detection limits of ±25 µÎµ and ±0.2 °C. These results show the potential of this approach for the development of point sensors, which can be easily wavelength-multiplexed.

Measurement of the soliton number in guiding media through continuum generation.

No general approach is available yet to measure directly the ratio between chromatic dispersion and the nonlinear coefficient, and hence the soliton number for a given optical pulse, in an arbitrary guiding medium. Here we solve this problem using continuum generation. We experimentally demonstrate our method in polarization-maintaining and single-mode fibers with positive and negative chromatic dispersion. Our technique also offers new opportunities to determine the chromatic dispersion of guiding media over a broad spectral range while pumping at a fixed wavelength.

Theory about the Embryo Cryo-Treatment.

Background: To create hypothesis, which can give a logical explanation related to the benefits of freezing/thawing embryos. Cryopreservation is not only a technology used for storing embryos, but also a method of embryo treatment that can potentially improve the success rate in infertile couples. Methods: From the analysis of multiple results in assisted reproductive technology, which have no satisfactory explanation to date, we found evidence to support a 'therapeutic' effect of the freezing/thawing of embryos on the process of recovery of the embryo and its subsequent implantation. Results: Freezing/thawing is a way to activate the endogenous survival and repair responses in preimplantation embryos. Several molecular mechanisms can explain the higher success rate of ET using thawed embryos compared to fresh ET in women of advanced reproductive age, the higher miscarriage rate in cases of thawed blastocyst ET compared to thawed ET at early cleavage embryo, and the higher perinatal parameters of born children after thawed ET. Embryo thawing induces a stress. Controlled stress is not necessarily detrimental, because it generates a phenomenon that is counteracted by several known biological responses aimed to repair mitochondrial damage of membrane and protein misfolding. The term for favorable biological responses to low exposures to stress is called hormesis. Conclusions: This thesis will summarize the role of cryopreservation in the activation of a hormetic response, preserving the mitochondrial function, improving survival, and having an impact on the process of implantation, miscarriage, and the development of pregnancy.

Wideband tuning of four-wave mixing in solid-core liquid-filled photonic crystal fibers.

We present an experimental study of parametric four-wave mixing generation in photonic crystal fibers that have been infiltrated with ethanol. A silica photonic crystal fiber was designed to have the proper dispersion properties after ethanol infiltration for the generation of widely spaced four-wave mixing (FWM) bands under 1064 nm pumping. We demonstrate that the FWM bands can be tuned in a wide wavelength range through the thermo-optic effect. Band shifts of 175 and over 500 nm for the signal and idler bands, respectively, are reported. The reported results can be of interest in many applications, such as CARS microscopy.

Supercontinuum generation at 800 nm in all-normal dispersion photonic crystal fiber.

We have numerically investigated the supercontinuum generation and pulse compression in a specially designed all-normal dispersion photonic crystal fiber with a flat-top dispersion curve, pumped by typical pulses from state of the art Ti:Sapphire lasers at 800 nm. The optimal combination of pump pulse parameters for a given fiber was found, which provides a wide octave-spanning spectrum with superb spectral flatness (a drop in spectral intensity of ~1.7 dB). With regard to the pulse compression for these spectra, multiple-cycle pulses (~8 fs) can be obtained with the use of a simple quadratic compressor and nearly single-cycle pulses (3.3 fs) can be obtained with the application of full phase compensation. The impact of pump pulse wavelength-shifting relative to the top of the dispersion curve on the generated SC and pulse compression was also investigated. The optimal pump pulse wavelength range was found to be 750 nm < λp < 850 nm, where the distortions of pulse shape are quite small (< -3.3 dB). The influences of realistic fiber fabrication errors on the SC generation and pulse compression were investigated systematically. We propose that the spectral shape distortions generated by fiber fabrication errors can be significantly attenuated by properly manipulating the pump.

Two-core transversally chirped microstructured optical fiber refractive index sensor.

We present a sensing architecture consisting of a two-core chirped microstructured optical fiber (MOF) for refractive index sensing of fluids. We show that by introducing a chirp in the hole size, the MOF can be a structure with decoupled cores, forming a Mach-Zehnder interferometer in which the analyte directly modulates the device transmittance by its differential influence on the effective refractive index of each core mode. We show that by filling all fiber holes with analyte, the sensing structure achieves high sensitivity (transmittance changes of 300 per RIU at 1.42) and has the potential for use over a wide range of analyte refractive index.

Femtosecond parabolic pulse shaping in normally dispersive optical fibers.

Formation of parabolic pulses at femtosecond time scale by means of passive nonlinear reshaping in normally dispersive optical fibers is analyzed. Two approaches are examined and compared: the parabolic waveform formation in transient propagation regime and parabolic waveform formation in the steady-state propagation regime. It is found that both approaches could produce parabolic pulses as short as few hundred femtoseconds applying commercially available fibers, specially designed all-normal dispersion photonic crystal fiber and modern femtosecond lasers for pumping. The ranges of parameters providing parabolic pulse formation at the femtosecond time scale are found depending on the initial pulse duration, chirp and energy. Applicability of different fibers for femtosecond pulse shaping is analyzed. Recommendation for shortest parabolic pulse formation is made based on the analysis presented.

A refractive index sensor based on the resonant coupling to cladding modes in a fiber loop.

We report an easy-to-build, compact, and low-cost optical fiber refractive index sensor. It consists of a single fiber loop whose transmission spectra exhibit a series of notches produced by the resonant coupling between the fundamental mode and the cladding modes in a uniformly bent fiber. The wavelength of the notches, distributed in a wavelength span from 1,400 to 1,700 nm, can be tuned by adjusting the diameter of the fiber loop and are sensitive to refractive index changes of the external medium. Sensitivities of 170 and 800 nm per refractive index unit for water solutions and for the refractive index interval 1.40-1.442, respectively, are demonstrated. We estimate a long range resolution of 3 × 10(-4) and a short range resolution of 2 × 10(-5) for water solutions.

Vertical transmission of maternal DNA through extracellular vesicles associates with altered embryo bioenergetics during the periconception period.

The transmission of DNA through extracellular vesicles (EVs) represents a novel genetic material transfer mechanism that may impact genome evolution and tumorigenesis. We aimed to investigate the potential for vertical DNA transmission within maternal endometrial EVs to the pre-implantation embryo and describe any effect on embryo bioenergetics. We discovered that the human endometrium secretes all three general subtypes of EV - apoptotic bodies (ABs), microvesicles (MVs), and exosomes (EXOs) - into the human endometrial fluid (EF) within the uterine cavity. EVs become uniformly secreted into the EF during the menstrual cycle, with the proportion of different EV populations remaining constant; however, MVs contain significantly higher levels of mitochondrial (mt)DNA than ABs or EXOs. During the window of implantation, MVs contain an eleven-fold higher level of mtDNA when compared to cells-of-origin within the receptive endometrium, which possesses a lower mtDNA content and displays the upregulated expression of mitophagy-related genes. Furthermore, we demonstrate the internalization of EV-derived nuclear-encoded (n)DNA/mtDNA by trophoblast cells of murine embryos, which associates with a reduction in mitochondrial respiration and ATP production. These findings suggest that the maternal endometrium suffers a reduction in mtDNA content during the preconceptional period, that nDNA/mtDNA become packaged into secreted EVs that the embryo uptakes, and that the transfer of DNA to the embryo within EVs occurs alongside the modulation of bioenergetics during implantation.

Alignment-free, all-spliced fiber laser source for CARS microscopy based on four-wave-mixing.

An environmentally-stable low-repetition rate fiber oscillator is developed to produce narrow-bandwidth pulses with several tens of picoseconds duration. Based on this oscillator an alignment-free all-fiber laser for multi-photon microscopy is realized using in-fiber frequency conversion based on four-wave-mixing. Both pump and Stokes pulses for coherent anti-Stokes Raman scattering (CARS) microscopy are readily available from one fiber end, intrinsically overlapped in space and time, which drastically simplifies the experimental handling for the user. The complete laser setup is mounted on a home-built laser scanning microscope with small footprint. High-quality multimodal microscope images of biological tissue are presented probing the CH-stretching resonance of lipids at an anti-Stokes Raman-shift of 2845 cm(-1) and second-harmonic generation of collagen. Due to its simplicity, compactness, maintenance-free operation, and ease-of-use the presented low-cost laser is an ideal source for bio-medical applications outside laser laboratories and in particular inside clinics.

Bioactive or Drug-Eluting Stents in 75 Years or Older Patients: The BIODES-75 Registry.

BACKGROUND: TiNO-coated BAS have demonstrated competitive outcomes compared to drug-eluting stents (DES). These devices allow short antiplatelet regimens and may be a good option for the growing elderly population undergoing percutaneous coronary intervention (PCI). METHODS: Multicenter observational trial in routine clinical practice. A propensity-score matched analysis compared a prospective cohort of patients ≥ 75 years undergoing PCI with BAS, with a contemporary and retrospective cohort treated with last-generation DES. The co-primary endpoints of the study were the Target-Lesion-Failure (Cardiac death, non-fatal myocardial infarction, or target lesion revascularization) and Major Adverse Cardiovascular Events (total death, non-fatal myocardial infarction, stroke, or new revascularization) at 1 year. RESULTS: Whole population included 1000 patients, and 326 patients in each group were matched for analysis. No differences in primary endpoints were found: TLF 10.4% vs. 11% (HR 0.96 (Confidence Interval 95%, 0.36-1.7; p = 0.87)) and MACE 16.3% vs. 17.2% (HR 0.98 (Confidence Interval 95%; 0.3-1.5, p = 0.93)). Patients treated with BAS received shorter antiplatelets regimens (dual antiplatelet therapy at 1 year, 25.7% vs. 70.6%, p = 0.0001), and they presented lower incidence of bleeding (3.7% vs. 11.7%, HR 0.3 (IC 95% 0.16-0.6, p = 0.001)). CONCLUSION: In this real-life registry of patients ≥ 75 years, BAS were similar to the latest-generation DES in terms of efficacy and reduced the duration of the antithrombotic therapy, lowering bleeding events.

Electrically tunable photonic true-time-delay line.

We present a new application of the acousto-optic superlattice modulation of a fiber Bragg grating based on the dynamic phase and group delay properties of this fiber-optic component. We demonstrate a tunable photonic true-time-delay line based on the group delay change of the light reflected from the grating sidebands. The delay is electrically tuned by adjusting the voltage applied to a piezoelectric transducer that generates the acoustic wave propagating along the grating. In our experiments, a true-time delay of 400 ps is continuously adjusted (300 ps within the 3 dB amplitude range of the first sideband), using a 12 cm long uniform grating.

Correction to: Double chimney stent technique in bilateral sequential coronary occlusion during corevalve valve-in-valve procedure.

This corrects the article DOI: 10.23736/S0026-4725.19.05064-3.

Doubly active Q switching and mode locking of an all-fiber laser.

Simultaneous and independent active Q switching and active mode locking of an erbium-doped fiber laser is demonstrated using all-fiber modulation techniques. A magnetostrictive rod attached to the output fiber Bragg grating modulates the Q factor of the Fabry-Perot cavity, whereas active mode locking is achieved by amplitude modulation with a Bragg-grating-based acousto-optic device. Fully modulated Q-switched mode-locked trains of optical pulses were obtained for a wide range of pump powers and repetition rates. For a Q-switched repetition rate of 500 Hz and a pump power of 100 mW, the laser generates trains of 12-14 mode-locked pulses of about 1 ns each, within an envelope of 550 ns, an overall energy of 0.65 microJ, and a peak power higher than 250 W for the central pulses of the train.

[Evaluation of the consultants to a urology service at hospital level]. / Valoración de las interconsultas realizadas a un servicio de urología, a nivel hospitalario.

OBJECTIVE: The main objectives of this study were to value the quality of the contained information, the characteristics of the consultants (IC) and as well as to know the performance carried out by the service of Urology in our hospital. MATERIAL AND METHODS: It was carried out an observational descriptive study where the documents of IC picked up by the service of Urology during 8 months were analyzed. Previously defined approaches of quality were used by Irazábal et al (changed) and Batista Miranda JE et al. RESULTS: They were picked up a total of 411 IC, arrivals to the service in a serial way. Coming from 27 hospital services. 82.2% of the derivatived patients were male. The half age of the patients was of 63, 25 years. 192 patients had personal urological records of interest (47%). The IC grouped in 27 different reasons. The reason of more frequent consultation was the incidentaloma with 21.5%. Regarding the grade of execution of the document of IC: there was perseverance of filiation data (96.3%), a description of the symptoms was in 68.2% and the physical examination appeared reflected in 8.8% of the total of the IC. They were requested as normal IC 63.4%, preferent 25% and urgent 11.7%. The days of answer to the IC it was of stocking of 1,45 days with typical deviation of 1,65 days. According to the established approaches, to classify the documents for adaptation level, they were classified as inappropriate to 32.9% of the IC (n = 135). They were classified in grade 1 the 44.6% (n = 183), grade 2 20% (n = 82) and grade 3 2.4% (n = 10). The attitude that was taken: it was remitted to External Consultations of Urology to 10.5% of the total of the IC, to the Center of Specialized Attention to 7.8%, it was requested complementary tests to 7.8%, it was remitted to the functional Tests of Urology, for the realization of some complementary test to 61 patients (14.9%), it was presented in Clinical Session of Urology to 5,6% of the patients, he/she moved to the Service of Urology to 2 patients (0.5%) and he/she took some other therapeutic attitude in 19.6%, these results had a p = 0.000 significance. CONCLUSION: In our study, we observe a high percentage as for the perseverance of the data of lightly inferior filiation in the description of the symptoms and considered low in the physical exploration. A high percentage of inappropriate considered IC. Regarding the attitude that took the Service of Urology, maybe had a low used of the Functional Unit. Until the moment and under our knowledge a study carried out in the environment from the realized IC to the Service of Urology in a Hospital of third level only exists and we believe that the realization of studies would improve the quality from the attendance to our patients.

The Feasibility and Safety of Ambulatory Percutaneous Coronary Interventions in Complex Lesions.

BACKGROUND: The safety and feasibility of ambulatory PCI has been demonstrated in selected patients with "simple" lesions, but it is not well known whether it could be applied in more "complex" scenarios. METHODS: Main objective is to assess the feasibility and safety of ambulatory complex PCI. Prospective multicentre registry of 1047 consecutive patients planned for ambulatory trans-radial PCI. Outcomes in patients with "complex angioplasty" (CA group: 313 (30%)) were analysed and compared with those of "simple angioplasty" (SA group: 734, 70%). The feasibility (% of patients finally discharged) and safety (MACE at 24 h and at 1 month) were compared between groups. We also analyse admissions, visits to the emergency department and minor vascular complications. RESULTS: Feasibility was higher for SA (80.6% vs. 63.6%, OR 1.89, 95% CI 1.52-2.35, p < 0.001). Ambulatory PCI was very safe in both groups. In CA no MACE occurred at 24 h (vs. 0.17% SA) or 30 days (vs. 0.68% in SA). There were also no differences in re-admissions, visits to the emergency department or minor vascular complications (there was a non-significant tendency to higher rate of radial occlusion at 1 month in the CA group, 5.5% vs. 2.7%, p: 0.07). CONCLUSIONS: The feasibility of ambulatory PCI in selected patients with complex lesions is lower than in simple lesions, however when it is possible, it is as safe as in selected patients with simple lesions.

Refractometric sensor based on whispering-gallery modes of thin capillarie.

Whispering-gallery modes resonances of submicron wall thickness capillaries exhibit very large wavelength shifts as a function of the refractive index of the medium that fills the inside. The sensitivity to refractive index changes is larger than in other optical microcavities as microspheres, microdisks and microrings. The outer surface where total internal reflection takes place remains always in air, enabling the measure of refractive index values higher than the refractive index of the capillary material. The fabrication of capillaries with submicron wall thickness has required the development of a specific technique. A refractometer with a response higher than 390 nm per refractive index unit is demonstrated. These sensors are readily compatible with microfluidic systems.

Safety of transradial diagnostic cardiac catheterization in patients under oral anticoagulant therapy.

BACKGROUND: Cardiac catheterization in anticoagulated patients is usually performed after the anticoagulation has been withdrawn, at least in the previous 48h, and sometimes bridging therapy with heparin is used. METHODS: A prospective observational study including 489 patients undergoing transradial catheterization was conducted. A total of 140 patients were under acenocoumarol (group A) and they were compared with the remainder (group B) for complications after the procedure (bleeding and vascular access complications). RESULTS: Patients in group A were older (74±12 years vs. 68±17 years, p<0.01) and the main indication for anticoagulation was atrial fibrillation (58.6%). No complications occurred during the procedures. There were no acute bleedings just after the bandage removal. During the first 24h, only 3 (2.1%) radial occlusions in group A and 2 (0.6%) in group B (p=0.14) were recorded. Hematomas between 5 and 10cm appeared in 5% of the group A vs. 4.6% in group B. During the 1-month follow-up period, one more radial occlusion in each group was recorded and there were 4 (1.1%) additional mild hematomas in group B and none in group A (p=0.48). CONCLUSIONS: Performing a transradial diagnostic cardiac catheterization without removal of the oral chronic anticoagulation appears safe in patients under acenocumarol therapy.

Safety and Feasibility of Outpatient Percutaneous Coronary Intervention in Selected Patients: A Spanish Multicenter Registry.

INTRODUCTION AND OBJECTIVES: The exponential increase in coronary interventions plus the generalization of the radial approach represent the ideal scenario for starting outpatient angioplasty programs with the aim of reducing the costs while maintaining safety. This article reports data from a multicenter Spanish registry on fully ambulatory transradial angioplasty in selected patients for the first time. METHODS: Prospective registry of elective outpatient transradial-ulnar angioplasty in patients with stable coronary disease. Patients were discharged the same day and were followed up at 24hours and 30 days. Safety and feasibility were analyzed. RESULTS: Of the 723 patients included (76% male; age, 66.6±10.5 years), 533 (73.7%) were finally discharged after 4 to 12hours of surveillance. Among the remaining 190 (26.7%) patients, the most common reason for hospitalization was clinical instability after the procedure (60.5%). Independent predictors of admission were a history of peripheral artery disease, a higher baseline creatinine level, ad hoc performance of the procedure, and multivessel disease. At 24hours, there was 1 major adverse event in 1 patient (0.19%), who required hospitalization for major bleeding not related to vascular access. At 30 days, there were 3 major adverse events (0.56%): 1 subacute stent thrombosis, 1 revascularization of a vessel other than the treated vessel, and 1 minor stroke. Eight patients (1.5%) required admission at 30 days. CONCLUSIONS: The application of an outpatient transradial-ulnar angioplasty program with discharge after 4 to 12 hours' surveillance is safe and feasible in well-selected patients.