European Vitreoretinal Society Macular Hole Study, Prognostic Factors for Anatomical and Functional Success

Background: To identify prognostic preoperative and intraoperative factors for anatomical and visual success of idiopathic macular hole (MH) surgery. Methods: We conducted a non-randomized, collaborative multicenter study using data of 4207 MH surgery from 140 surgeons. Main study outcomes were anatomical closure and best corrected visual acuity (BCVA) improvement postoperative at 6-12 months. Results: Information on anatomical success was available for 4138 eyes of 4207 operations. Anatomical closure of MH was achieved in 85.7% (3546 eyes). Closure was higher in smaller MH (stages 1-2 versus stage 3: OR=0.35; stage 2 versus stage 4: OR=0.16, and in MH with shorter duration before the operation (OR=0.94). Macular Holes were more likely to close when dyes were used to facilitate internal limiting membrane (ILM) peeling (odds ratio=1.73 to 3.58). The most important predictors of postoperative BCVA were the preoperative BCVA (estimate=0.39, p<0.001) and closure of the macular hole (estimate=0.34, p<0.001). We observed Larger improvement in BCVA in combined vitrectomy and phacoemulsification (estimate = 0.10) and post cataract surgery in phakic eyes (estimate=0.05). Retinal tears occurred in 5.1% of eyes, and were less with use of trocars (OR= -1.246) and in combined vitrectomy/ phacoemulsification surgery (OR= -0.688). Conclusion: This international survey confirmed that staining with dyes improves anatomical results but not visual outcomes. After surgery, visual acuity improved during the first year, and final visual acuity was better in both pseudophakic eyes and eyes that underwent cataract surgery during the first year following MH repair

THz packaging solution for low cost si-based 40 Gb/s wireless link system

This paper presents an innovative low-cost transmitter solution aimed at improving telecommunication networks capacities in order to support the massive data traffic growth. Sub-THz frequencies > 200 GHz are considered to target at least 40 Gb/s. The proposed transmitter consists of a Silicon Photonic integrated sub-THz source and an industrial antenna integrated in HDI organic packaging substrate. As these components were experimentally evaluated, a real-time error free wireless data transmission of 10 Gb/s was successfully achieved and an antenna gain of 5.5 dBi was measured in the broadside direction from 220 GHz to 240 GHz (8.7% relative bandwidth). With the addition of a low-cost dielectric lens, a gain of 17 dBi was reached.info:eu-repo/semantics/acceptedVersio

Voltage controlled sub-THz detection with gated planar asymmetric nanochannels

[EN]This letter reports on room temperature sub-THz detection using self-switching diodes based on an AlGaN/GaN heterostructure on a Si substrate. By means of free-space measurements at 300 GHz, we demonstrate that the responsivity and noise equivalent power (NEP) of sub-THz detectors based on planar asymmetric nanochannels can be improved and voltage controlled by means of a top gate electrode. A simple quasi-static model based on the DC measurements of the current-voltage curves is able to predict the role of the gate bias in its performance. The best values of voltage responsivity and NEP are achieved when the gate bias approaches the threshold voltage, around 600 V/W and 50 pW/Hz1/2, respectively. A good agreement is found between modeled results and those obtained from RF measurements under probes at low frequency (900MHz) and in free-space at 300 GHz

Imaging the early development of seeds

Imaging the early development of seeds

Coherent terahertz photonics

We present a review of recent developments in THz coherent systems based on photonic local oscillators. We show that such techniques can enable the creation of highly coherent, thus highly sensitive, systems for frequencies ranging from 100 GHz to 5 THz, within an energy efficient integrated platform. We suggest that such systems could enable the THz spectrum to realize its full applications potential. To demonstrate how photonics-enabled THz systems can be realized, we review the performance of key components, show recent demonstrations of integrated platforms, and give examples of applications

Low-threshold terahertz molecular laser optically pumped by a quantum cascade laser

We demonstrate a low-threshold, compact, room temperature, and continuous-wave terahertz molecular laser optically pumped by a mid-infrared quantum cascade laser. These characteristics are obtained, thanks to large dipole transitions of the active medium: NH3 (ammonia) in gas state. The low-power (<60 mW) laser pumping excites the molecules, thanks to intense mid-infrared transitions around 10.3 μm. The molecules de-excite by stimulated emission on pure inversion “umbrella-mode” quantum transitions allowed by the tunnel effect. The tunability of the quantum cascade laser gives access to several pure inversion transitions with different rotation states: we demonstrate the continuous-wave generation of ten laser lines around 1 THz. At 1.07 THz, we measure a power of 34 μW with a very low-threshold of 2 mW and a high differential efficiency of 0.82 mW/W. The spectrum was measured showing that the linewidth is lower than 1 MHz. To our knowledge, this is the first THz molecular laser pumped by a solid-state source and this result opens the way for compact, simple, and efficient THz source at room temperature for imaging applications

Early Reactional Hyperplasia and Neuronal Differentiation of the Ciliary Epithelium (CE) in Experimental Retinal Detachment (RD) with Proliferative VitreoRetinopathy (PVR) in the Porcine Eye

Background: Rare quiescent retinal progenitor cells have been isolated in the adult amphibian ciliary marginal zone (Hollyfield, 1968), then in the mammalian (Tropepe et al, 2000) (Ahmad et al, 2000) (Fischer and Rey, 2000) and human CE (Coles et al, 2004) (Ballios et al, 2011). This contingent might be inhibited in the adult eye by the signaling pathway ephrin (Chen, personal communication, ARVO 2012, submitted, Stem Cells). Retinal injury might be a triggering factor to quit the dormant state in the adult mammalian CE (Ooto, 2004) (Nickerson, 2007) (Nishiguchi 2008) (Kiyama et Wang, 2010), as it has been demonstrated also in the human brain (Moe et al, 2005) (Logan et al, 2006) . We have reported a CE proliferation with retinal neuronal and photoreceptor differentiation in three human eyes eviscerated for longstanding RD and PVR (Ducournau et al 2012). The CE strongly expressed EGFR. The concept of niche (Fischer and Rey, 2003) is now well established in stem cells recruitment processes. We have hypothezised that the disease RD and PVR might stimulate a dormant population of Retinal Progenitor Cells (RPCs) in the CE in the human eye in vivo in presence of a niche constituted by EGF. Proliferation in the ciliary body, together with nestin expression in ciliary MCM2+ (macrophage/microglia marker F4/80) cells were found in mice eyes with experimental RD, suggesting that RD might activate putative RPCs (Suburo et al, 2010). The aim of the present work was to study the CE in the porcine eye with experimental DR and PVR

Terahertz photomixers based on ultra-wideband horn antennas

International audienceWe review recent advances in the development of new terahertz photomixers based on the integration of an ultrafast photodetector with an ultra-wideband transverse electromagnetic wave horn antenna. We expose first a simplified theory of this antenna, the choice of the dimensions and the results of electromagnetic modeling. We expose then the technological process of the antenna and its integration with ultrafast photodetectors. In the last part we present a photomixing experiment and radiation patterns measurements.Cet article expose le développement récent d'une nouvelle génération de photomélangeurs térahertz basés sur l'intégration d'un photodétecteur ultra-rapide avec une antenne ultra-large bande de type cornet à onde transverse électromagnétique. Nous exposons d'abord la théorie simplifiée de cette antenne puis le choix des dimensions et les résultats de simulations électromagnétiques. Nous exposons ensuite le procédé de réalisation technologique de l'antenne et son intégration avec des photodétecteurs ultra-rapides. Enfin nous présentons une expérience de photomélange et des résultats de mesures de diagrammes de rayonnement