High Speed Visible Light Communication Using Blue GaN Laser Diodes

GaN-based laser diodes have been developed over the last 20 years making them desirable for many security and defence applications, in particular, free space laser communications. Unlike their LED counterparts, laser diodes are not limited by their carrier lifetime which makes them attractive for high speed communication, whether in free space, through fiber or underwater. Gigabit data transmission can be achieved in free space by modulating the visible light from the laser with a pseudo-random bit sequence (PRBS), with recent results approaching 5 Gbit/s error free data transmission. By exploiting the low-loss in the blue part of the spectrum through water, data transmission experiments have also been conducted to show rates of 2.5 Gbit/s underwater. Different water types have been tested to monitor the effect of scattering and to see how this affects the overall transmission rate and distance. This is of great interest for communication with unmanned underwater vehicles (UUV) as the current method using acoustics is much slower and vulnerable to interception. These types of laser diodes can typically reach 50-100 mW of power which increases the length at which the data can be transmitted. This distance could be further improved by making use of high power laser arrays. Highly uniform GaN substrates with low defectivity allow individually addressable laser bars to be fabricated. This could ultimately increase optical power levels to 4 W for a 20-emitter array. Overall, the development of GaN laser diodes will play an important part in free space optical communications and will be vital in the advancement of security and defence applications

Women Could Avoid Axillary Lymph Node Dissection by Choosing Breast-Conserving Therapy Instead of Mastectomy

Background The ACOSOG Z0011 trial showed that completion axillary lymph node dissection (cALND) can be safely omitted for some patients with T1-2 clinically node-negative breast cancer with one to two involved sentinel lymph nodes (SLNs) treated with breast-conserving therapy (BCT). There is little evidence for the safety of omitting cALND for mastectomy-treated patients. Consequently, cALND is often recommended for sentinel node-positive patients treated with mastectomy. The aim of this study is to determine the proportion of patients who could avoid cALND by choosing BCT instead of mastectomy at a tertiary cancer center. Patients and Methods All T1-2 clinically node-negative breast cancer patients treated with BCT or mastectomy between 2012 and 2017 with metastases in the SLN(s) were selected from a prospectively maintained database. Clinical factors and outcomes were evaluated between the two groups. Differences were compared using Wilcoxon rank-sum test, chi-square test or Fisher's exact test as appropriate. Significance was set at the 0.05 level for all analyses. Results A total of 306 patients were included, 199 (65.0%) of whom were treated with BCT and 107 (35.0%) with mastectomy. Patients treated with mastectomy were more often treated with cALND compared with those treated with BCT (71.0% versus 26.6%, p < 0.0001). Overall, 52 of the mastectomy patients (68.4%) could have avoided cALND if they had chosen BCT. Conclusions Patients treated with mastectomy are more likely to receive cALND than those treated with BCT. Axillary management should be addressed during discussion of primary tumor therapy, and cALND may be avoided when patients choose BCT instead of mastectomy

Automated Identification and Analysis of Visual Micro-experiments on Cellular Microarray

International audienceThis paper is an overview of the computer-based tools I designed at In-stitut Pasteur Korea in order to analyse a large quantity of microscopy cell based experiments. This development consisted in designing algorithms and software for automatically localize, identify and analyze cells on spots of cellular microarray at high resolution. We believe the applications of this work are numerous from genome wide loss of function screens to drug target deconvolution assays and diagnostic