High speed wireless communications are highly desirable for many industrial and scientific underwater applications. Acoustic communications suffer from high latency and limited data rates, while Radio Frequency communications are severely limited by attenuation in seawater. Optical communications are a promising alternative, offering high transmission rates (up to Gb/s), while water has relatively low attenuation at visible wavelengths. Here we demonstrate the use of series-connected micro-light-emitting-diode (μLED) arrays consisting of 6 μLED pixels either 60 μm or 80 μm in diameter and operating at 450 nm. These devices increase the output power whilst maintaining relatively high modulation bandwidth. Using orthogonal frequency division multiplexing (OFDM) we demonstrate underwater wireless data transmission at rates of up to 4.92 Gb/s, 3.22 Gb/s and 3.4 Gb/s over 1.5 m, 3 m and 4.5 m, respectively, with corresponding bit error ratios (BERs) of 1.5 × 10 −3 , 1.1 × 10 −3 and 3.1 × 10 −3 , through clear tap water, and Mb/s rates through >5 attenuation lengths (ALs) in turbid waters.
We demonstrate for first time the ultrafast properties of a newly formed porous Au nanostructure. The properties of the porous nanostructure are compared with those of a solid gold film using time-resolved optical spectroscopy. The experiments suggest that under the same excitation conditions the relaxation dynamics are slower in the former. Our observations are evaluated by simulations based on a phenomenological rate equation model. The impeded dynamics has been attributed to the porous nature of the structure in the networks, which results in reduced efficiency during the dissipation of the laser-deposited energy. Importantly, the porosity of the complex three-dimensional nanostructure is introduced as a geometrical control parameter of its ultrafast electron transport.
The HYPEDIA study aimed at evaluating the implementation of the 2018 European guidelines for treating hypertension in primary care. A nationwide prospective non-interventional cross-sectional study was performed in consecutive untreated or treated hypertensives recruited mainly in primary care in Greece. Participants’ characteristics, office blood pressure (BP) (triplicate automated measurements, Microlife BPA3 PC) and treatment changes were recorded on a cloud platform. A total of 3,122 patients (mean age 64 ± 12.5 [SD] years, 52% males) were assessed by 181 doctors and 3 hospital centers. In 772 untreated hypertensives (25%), drug treatment was initiated in the majority, with monotherapy in 53.4%, two-drug combination in 36.3%, and three drugs in 10.3%. Angiotensin receptor blocker (ARB) monotherapy was initiated in 30%, ARB/calcium channel blocker (CCB) 20%, ARB/thiazide 8%, angiotensin converting enzyme inhibitor (ACEi)-based 19%. Of the combinations used, 97% were in single-pill. Among 977 treated hypertensives aged <65 years, 79% had BP ≥ 130/80 mmHg (systolic and/or diastolic), whereas among 1,373 aged ≥65 years, 66% had BP ≥ 140/80 mmHg. ARBs were used in 69% of treated hypertensives, CCBs 47%, ACEis 19%, diuretics 39%, beta-blockers 19%. Treatment modification was decided in 53% of treated hypertensives aged <65 years with BP ≥ 130/80 mmHg and in 62% of those ≥65 years with BP ≥ 140/80 mmHg. Renin-angiotensin system blocker-based therapy constitutes the basis of antihypertensive drug treatment in most patients in primary care, with wide use of single-pill combinations. In almost half of treated uncontrolled hypertensives, treatment was not intensified, suggesting suboptimal implementation of the guidelines and possible physician inertia.
Integrated blue-violet and blue-green micro-LED arrays, fabricated via a transfer printing method, were employed to demonstrate wavelength division multiplexing underwater data transmission at 100 Mb/s over up to 9 attenuation lengths in a 1.5 m long water tank.
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