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We present a general-purpose three-dimensional interconnection network that models various parallel operations between two data planes. This volume interconnection system exhibits reconfigurable capabilities because of parallel and externally weighted interconnection modules, called nodes. We propose a generic optical implementation based on the cascading of two planar hologram arrays, coupled with a bistable optically addressed spatial light modulator. Th role of this component is discussed in terms of energy regeneration and spatial cross-talk limitation. As an example, a binary matrix-matrix multiplier is implemented that uses a ferroelectric liquid-crystal light valve.

We address free-space optical interconnections based on cascaded multifacet holographic elements, including an intermediate regeneration of the optical signals. Particular attention is paid to digital hologram encoding in the case of highly interconnected planes. Degrees of freedom selected in the reconstruction plane are used for satisfying both holographic-encoding and signal constraints. An iterative Fourier-transform algorithm is chosen because of its ability to incorporate constraint considerations.

Epitestosterone is the 17α-epimer of testosterone. This steroid possesses antiandrogenic activities. The mechanism of action of epitestosterone has not been elucidated. The aim of this study was to investigate the nonclassical eff ect of epitestosterone on the membrane of Sertoli cells in proliferative phase (rats aged 15 days) and in nonproliferative phase (rats aged 21 and 35 days). The membrane potential of Sertoli cells was recorded using a standard single microelectrode technique. Epitestosterone (0.5, 1, and 2 μM) or testosterone (1 μM) was administered alone and after infusion with fl utamide (1 μM), verapamil (100 μM), or U-73122 (2 μM). The testes of rats aged 12-15 days were preincubated with 45 Ca 2 + with or without fl utamide (1 μM) and incubated with epitestosterone (1 μM) or testosterone (1 μM). Epitestosterone and testosterone produced a depolarization in the membrane potential and increased the membrane input resistance on Sertoli cells from rats of all 3 ages. The eff ect of epitestosterone did not change after perfusion with fl utamide. Epitestosterone increased 45 Ca 2+ uptake within 5 min and this eff ect was not inhibited by fl utamide. The absence of an eff ect by fl utamide suggests that epitestosterone acts independently of the intracellular androgen receptor. The depolarizing eff ect was inhibited by verapamil, a voltage- dependent calcium channel blocker, and by U-73122, a phospholipase C inhibitor. These results indicate that epitestosterone acts on the membrane via a nonclassical signaling pathway; the eff ect was similar to the testosterone action on membrane of Sertoli cells in whole seminiferous tubules from rat testes. [ABSTRACT FROM AUTHOR]

Holography is often considered as the most promising immersive technology because it provides all the depth cues of the human visual system. Some limitations still need to be overcome such as the huge computational load of high-definition holograms and the noise introduced in the reconstructed scene during the quantization process. In this paper, we propose what we believe is a novel view-specific layer-based stereogram approach combined with a view-dependent error diffusion algorithm that aims to solve those limitations. This method selects the light waves of the 3D scene that reach a specific viewing area and leverages this particular configuration to apply an error diffusion algorithm. Two additional quality enhancement features are observed: the reduction of the conjugate order perceptibility and the increased brightness of the reconstructed scene. Numerical and optical experiments demonstrate the time savings and quality enhancements of our approach.

Recording a video scene as seen by an observer, materializing where is focused his visual attention and allowing an external person to point at a given object in this scene, could be beneficial for various applications such as medical education or remote training. Such a versatile device, although tested at the experimental laboratory demonstrator stage, has never been integrated in a compact and portable way in a real environment. In this context, we built a low-cost, light-weight, head-mounted device integrating a miniature camera and a laser pointer that can be remotely controlled or servo-controlled by an eye tracker. Two motorizations were implemented and tested (pan/tilt and Rilsey-prisms-based). The video was both recorded locally and transmitted wirelessly. Risley prisms allowed finer remote control of camera or laser pointer orientation (0.1° vs. 0.35°), but data processing and Wi-Fi transmission incur significant latency (~0.5 s) limiting the servo-controlling by eye movements. The laser beam was spatially shaped by a Diffractive Optical Element to facilitate object illumination or recognition. With this first proof-of-concept prototype, the data stream needs to be optimized to make full use of the eye tracker, but this versatile device can find various applications in education, healthcare or research.

Importance: The presumed proarrhythmic action of caffeine is controversial. Few studies have assessed the effect of high doses of caffeine in patients with heart failure due to left ventricular systolic dysfunction at high risk for ventricular arrhythmias., Objective: To compare the effect of high-dose caffeine or placebo on the frequency of supraventricular and ventricular arrhythmias, both at rest and during a symptom-limited exercise test., Design, Setting, and Participants: Double-blinded randomized clinical trial with a crossover design conducted at the heart failure and cardiac transplant clinic of a tertiary-care university hospital. The trial included patients with chronic heart failure with moderate-to-severe systolic dysfunction (left ventricular ejection fraction <45%) and New York Heart Association functional class I to III between March 5, 2013, and October 2, 2015., Interventions: Caffeine (100 mg) or lactose capsules, in addition to 5 doses of 100 mL decaffeinated coffee at 1-hour intervals, for a total of 500 mg of caffeine or placebo during a 5-hour protocol. After a 1-week washout period, the protocol was repeated., Main Outcomes and Measures: Number and percentage of ventricular and supraventricular premature beats assessed by continuous electrocardiographic monitoring., Results: We enrolled 51 patients (37 [74%] male; mean [SD] age, 60.6 [10.9] years) with predominantly moderate-to-severe left ventricular systolic dysfunction (mean [SD] left ventricular ejection fraction, 29% [7%]); 31 [61%] had an implantable cardioverter-defibrillator device. No significant differences between the caffeine and placebo groups were observed in the number of ventricular (185 vs 239 beats, respectively; P = .47) and supraventricular premature beats (6 vs 6 beats, respectively; P = .44), as well as in couplets, bigeminal cycles, or nonsustained tachycardia during continuous electrocardiographic monitoring. Exercise test-derived variables, such as ventricular and supraventricular premature beats, duration of exercise, estimated peak oxygen consumption, and heart rate, were not influenced by caffeine ingestion. We observed no increases in ventricular premature beats (91 vs 223 vs 207 beats, respectively) in patients with higher levels of plasma caffeine concentration compared with lower plasma levels (P = .91) or with the placebo group (P = .74)., Conclusions and Relevance: Acute ingestion of high doses of caffeine did not induce arrhythmias in patients with systolic heart failure and at high risk for ventricular arrhythmias., Trial Registration: clinicaltrials.gov Identifier: NCT02045992.

In this paper, the characterization of a perfluorinated graded-index polymer optical fiber (PF-GIPOF) for a high-bitrate indoor optical wireless system is reported. PF-GIPOF is used here to interconnect different optical wireless access points that distribute optical free-space high-bitrate wireless communication cells. The PF-GIPOF channel is first studied in terms of transmission attenuation and frequency response and, in a second step, the spatial power profile distribution at the fiber output is analyzed. Both characterizations are performed under varying restricted mode launch conditions, enabling us to assess the transmission channel performance subject to potential connectorization errors within an environment where the end users may intervene by themselves on the home network infrastructure.

This Letter presents the design of a diffractive beam diffuser to homogenize the irradiance within optical free-space cells generated from multimode fibers in an indoor high-speed network environment. Native speckled beams with a Gaussian envelope are transformed into circular flat-top distributions to guarantee a constant signal-to-noise ratio at the wireless receiving stage. Design considerations followed by the device fabrication and test results are given, showing its ability to shape narrow line-of-sight optical wireless cells operating at the Gbps range.

We report preliminary results concerning a free-space optical switch between single-mode fibers with a ferroelectric liquid-crystal (FLC) spatial light modulator (SLM). In particular, we show experimentally that such a device can operate in a polarization-insensitive manner. The influence of the geometrical and physical features of the FLC SLM on the overall performance of the optical fiber switch are also discussed.