Visible Light Communication Using a Blue GaN μLED and Fluorescent Polymer Color Converter

This letter presents a novel technique to achieve high-speed visible light communication (VLC) using white light generated by a blue GaN mu LED and a yellow fluorescent copolymer. We generated white light suitable for room illumination by optimizing the ratio between the blue electroluminescence of the mu LED and yellow photoluminescence of the copolymer color converter. Taking advantage of the components' high bandwidth, we demonstrated 1.68 Gb/s at a distance of 3 cm (at 240 lx illumination). To the best of our knowledge, this is the fastest white light VLC results using a single blue LED/color converter combination.PostprintPeer reviewe

Azimuthal anchoring of nematic on undulated substrate: Elasticity

We measure the azimuthal anchoring energy of the nematic 5CB on sinusoidal holographic unidimensional and bidimensional gratings. We find that the anchoring strength is almost the same for all of the gratings and up to one order of magnitude stronger than expected by the topographic mechanism proposed by Berreman. We observe strong memory effects which dominate both the elastic anchoring and the easy axis gliding. We show that these memory effects limit from below the anchoring energy and are the main obstacle in the realization of substrates with weak anchoring conditions

Definitive Radiotherapy Combined with Targeted Therapy in Locoregional Advanced Cancer of Larynx, Hypopharynx and Oropharynx-preliminary Report of Single Institution Experience, Patients Compliance to the Treatment Protocol and Early Toxicity

Objective: To report the clinical experience of Radiotherapy Departmentat University Hospital St. Marina, Varna, with definitive radiotherapycombined with targeted therapy Cetuximab in patients with locally advanced head and neck carcinoma (LAHNC), the observed toxicity and management protocol.Materials and Methods: The study included 36 patients with LAHNC who received definitive radiotherapy combined with Cetuximab in the period 2015-2018., VMAT and IGRT irradiation techniques were applied in all patients, with a prescription of total dose to 70Gy in the primary tumor and the involved lymph nodes, based on PET-CT. Cetuximab was administered according to the known protocol. Both Radiotheray and Medical Oncology Departments of the University Hospital “St. Marina” – Varna elaborated common protocol for premedication. The side effects were evaluated by the treating physician according to the CTCAE vers. 4.0.Results: During the application of the loading dose, an anaphylactic reaction was observed in 6 out of all 36 patients. The reduction of maintenance doses with 75% was done only in two patients without interruption of radiotherapy schedule and the planned infusions. One patient refuses to continue therapy. One patient died of cardiac comorbidity in the second week. All the others 26 patients completed the full course radiotherapy combined with full dose target therapy, with only moderate toxicity up to grade 3. No haematological toxicity was observed.Conclusion: The reported patients compliance was high 75%, with no higher than grade 3 side effects and a good quality of life. To our knowledge currently, this is the first study in Bulgarian clinical practice regarding the application of Cetuximab in combination with radiation therapy and reporting of early toxicity and patients compliance

Management of High and Very High-Risk Subjects with Familial Hypercholesterolemia: Results from an Observational Study in Bulgaria

Background: Familial hypercholesterolaemia (FH) is a genetic disorder causing accelerated atherosclerosis and premature cardiovascular disease (CVD). This retrospective observational study examined the clinical characteristics and management of FH subjects in Bulgaria over a 12-month period

Multicentric atrial strain COmparison between two different modalities: MASCOT HIT study

Two methods are currently available for left atrial (LA) strain measurement by speckle tracking echocardiography, with two different reference timings for starting the analysis: QRS (QRS-LASr) and P wave (P-LASr). The aim of MASCOT HIT study was to define which of the two was more reproducible, more feasible, and less time consuming. In 26 expert centers, LA strain was analyzed by two different echocardiographers (young vs senior) in a blinded fashion. The study population included: healthy subjects, patients with arterial hypertension or aortic stenosis (LA pressure overload, group 2) and patients with mitral regurgitation or heart failure (LA volume–pressure overload, group 3). Difference between the inter-correlation coefficient (ICC) by the two echocardiographers using the two techniques, feasibility and analysis time of both methods were analyzed. A total of 938 subjects were included: 309 controls, 333 patients in group 2, and 296 patients in group 3. The ICC was comparable between QRS-LASr (0.93) and P-LASr (0.90). The young echocardiographers calculated QRS-LASr in 90% of cases, the expert ones in 95%. The feasibility of P-LASr was 85% by young echocardiographers and 88% by senior ones. QRS-LASr young median time was 110 s (interquartile range, IR, 78-149) vs senior 110 s (IR 78-155); for P-LASr, 120 s (IR 80-165) and 120 s (IR 90-161), respectively. LA strain was feasible in the majority of patients with similar reproducibility for both methods. QRS complex guaranteed a slightly higher feasibility and a lower time wasting compared to the use of P wave as the reference