Channelled spectrum liquid refractometer

We describe an experimental demonstration of a novel technique for liquid refractometry. A channeled spectrum is produced from an optical beam generated by a diode laser operating below threshold by intercepting half of the beam with a liquid cell. The spectrum is analyzed using a grating and a linear CCD array and provides information on the refractive index of the liquid. The experimental results show that accuracies of better than 0.3% in the index may be obtained with the present method

Novel software package to facilitate operation of any spectral (Fourier) OCT system

We present a novel software method (master-slave) to facilitate operation of any SDOCT system. This method relaxes constraints on dispersion compensation and k-domain re-sampling in SDOCT methods without requiring any changes in the hardware used

Covering the gap in depth resolution between OCT and SLO in imaging the retina

Access full text - https://doi.org/10.1117/12.427898Two instruments are now available for high depth resolution imaging of the retina. A scanning laser ophthalmoscope is a confocal instruments which can achieve no more than 0.3 mm depth resolution. A longitudinal OCT instrument uses a superluminescent diode which determines a depth resolution better than 20 microns. There is a gap in depth resolution between the two technologies. Therefore, different OCT configurations and low coherence sources are investigated to produce a choice of depth resolutions, and to cover the gap between the old confocal technology and the new OCT imaging method. We show that an instrument with adjustable depth resolution is especially useful for the en-face OCT technology. Such an instrument can bring additional benefits to the investigation process, where different requirements must be met. For instance, a poor depth resolution is required in the process of positioning the patient's eye prior to investigation. A good depth resolution is however necessary when imaging small details inside the eye. The utility of the OCT en-face imaging with adjustable coherence length for diagnostic is illustrated by images taken from the eye of a volunteer. Images with a similar aspect to those produced by a scanning laser ophthalmoscope can now be obtained in real time using the OCT principle

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

Route to OCT from OFS at University of Kent

A review is presented of several technical solutions developed by the Applied Optics Group (AOG) in the field of low coherence interferometry applied to optical fiber sensors (OFS) that subsequently allowed AOG to quickly progress in the field of optical coherence tomography (OCT). © 2011 University of Electronic Science and Technology of China and Springer-Verlag Berlin Heidelberg

160-Channel 0.5-nanosecond Hybrid Digital Correlator Based Upon Fiber Optic Delay Lines

In order to implement digitally the correlation function, three operations are needed: delay, multiplication and averaging. The hybrid architecture of a multichannel fiber optic digital correlator (MFODC) shown in Fig. 1 implements the delays using optical fibres and coaxial cables, the multiplication using AND gates and the averaging by repeating the measurements and collecting the data using high speed high capacity counters. The main advantage of this architecture as proposed in [1] and demonstrated in the first 8 channel 10 ns MFODC [2] is that it eliminates the clock distribution, which is a major impediment in increasing the speed of electronic correlators. Using shift registers and clock distribution, the commercially available electronic multichannel correlators have lag times no less than 5 ns.</jats:p

Variante simple de mode-locking avec applications dans la mesure du temps de réponse des dispositifs opto-électroniques

On présente une étude expérimentale sur une variante de mode-locking qui consiste dans la modulation de la longueur de la cavité couplée à la cavité laser. On indique aussi comment on peut construire rapidement, en utilisant cette méthode de mode-locking, une installation simple qui peut servir à la mesure des temps de réponse de certains photodétecteurs et de la dispersion des fibres optiques