Background and Purpose-We aimed to establish the prevalence, characteristics, and outcomes of intracranial atherosclerosis (ICAS) in China by a large, prospective, multicenter study. Methods-We evaluated 2864 consecutive patients who experienced an acute cerebral ischemia <7 days after symptom onset in 22 Chinese hospitals. All patients underwent magnetic resonance angiography, with measurement of diameter of the main intracranial arteries. ICAS was defined as ≥50% diameter reduction on magnetic resonance angiography. Results-The prevalence of ICAS was 46.6% (1335 patients, including 261 patients with coexisting extracranial carotid stenosis). Patients with ICAS had more severe stroke at admission and stayed longer in hospitals compared with those without intracranial stenosis (median National Institutes of Health Stroke Scale score, 3 versus 5; median length of stay, 14 versus 16 days; both P<0.0001). After 12 months, recurrent stroke occurred in 3.27% of patients with no stenosis, in 3.82% for those with 50% to 69% stenosis, in 5.16% for those with 70% to 99% stenosis, and in 7.27% for those with total occlusion. Cox proportional hazards regression analyses showed that the degree of arterial stenosis, age, family history of stroke, history of cerebral ischemia or heart disease, complete circle of Willis, and National Institutes of Health Stroke Scale score at admission were independent predictors for recurrent stroke at 1 year. The highest rate of recurrence was observed in patients with occlusion with the presence of ≥3 additional risk factors. Conclusions-ICAS is the most common vascular lesion in patients with cerebrovascular disease in China. Recurrent stroke rate in our study was lower compared with those of previous clinical trials but remains unacceptably high in a subgroup of patients with severe stenosis. (Stroke. 2014;45:663-669.)

The generation of high-quality entangled photon pairs has been being a long-sought goal in modern quantum communication and computation. To date, the most widely-used entangled photon pairs are generated from spontaneous parametric downconversion, a process that is intrinsically probabilistic and thus relegated to a regime of low pair-generation rates. In contrast, semiconductor quantum dots can generate triggered entangled photon pairs via a cascaded radiative decay process, and do not suffer from any fundamental trade-off between source brightness and multi-pair generation. However, a source featuring simultaneously high photon-extraction efficiency, high-degree of entanglement fidelity and photon indistinguishability has not yet been reported. Here, we present an entangled photon pair source with high brightness and indistinguishability by deterministically embedding GaAs quantum dots in broadband photonic nanostructures that enable Purcell-enhanced emission. Our source produces entangled photon pairs with a record pair collection probability of up to 0.65(4) (single-photon extraction efficiency of 0.85 (3)), entanglement fidelity of 0.88(2), and indistinguishabilities of 0.901(3) and 0.903 (3), which immediately creates opportunities for advancing quantum photonic technologies.

We present a systematic procedure for designing "flat bands" of photonic crystal waveguides for slow light propagation. The procedure aims to maximize the group index - bandwidth product by changing the position of the first two rows of holes of W1 line defect photonic crystal waveguides. A nearly constant group index - bandwidth product is achieved for group indices of 30-90 and as an example, we experimentally demonstrate flat band slow light with nearly constant group indices of 32.5, 44 and 49 over 14 nm, 11 nm and 9.5 nm bandwidth around 1550 nm, respectively.

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Reducing interface recombination boosts the Voc for perovskite solar cells.