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Tungsten disulphide (WS), which exhibits excellent saturable absorption properties, has attracted much attention in the applications of photonic devices. In this paper, WS is applied for the preparation of a saturable absorber (SA). Using the pulsed laser deposition (PLD) method, WS is deposited on the side surface of the tapered fiber. In order to obtain larger non-linearity of the SAs with evanescent wave interaction, the tapered fiber had a smaller waist diameter and longer fused zone. Gold film was deposited on the fiber-taper WS SAs to improve their reliability and avoid oxidation and corrosion. Employing the balanced twin-detector method, the modulation depth of the fiber-taper WS SAs was measured to be 17.2%. With the fiber-taper WS SA, a generated pulse with 246 fs duration and a 57 nm bandwidth was obtained at 1561 nm. The electrical signal to noise ratio was better than 92 dB. To our knowledge, the pulse duration was the shortest among the reported all-fiber lasers with transition metal dichalcogenide (TMD) SAs. These results indicate that fiber-taper WS SAs with smaller waist diameter and longer fused zone are promising photonic devices for ultrashort pulse generation in all-fiber lasers.

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Femtosecond optical pulses have applications in optical communication, astronomical frequency combs, and laser spectroscopy. Here, a hybrid mode-locked erbium-doped fiber (EDF) laser with topological insulator (TI) is proposed, for the first time to our best knowledge. The pulsed laser deposition (PLD) method is employed to fabricate the fiber-taper TI saturable absorber (TISA). By virtue of the fiber-taper TISA, the hybrid EDF laser is passively mode-locked using the nonlinear polarization evolution (NPE), and emits 70 fs pulses at 1542 nm, whose 3 dB spectral width is 63 nm with a repetition rate and transfer efficiency of 95.4 MHz and 14.12%, respectively. Our experiments indicate that the proposed hybrid mode-locked EDF lasers have better performance to achieve shorter pulses with higher power and lower mode-locking threshold in the future.

Background Rapid economic and social development in China has resulted in severe air pollution and consequent adverse impacts on society. The health effects of air pollution have been widely studied. Methods Using information from the China Health and Retirement Longitudinal Study (CHARLS) database, we established a hierarchical linear model combining pollution and socioeconomic and psychosocial variables to examine the effects of air pollution on public health in China. Local air pollution was characterized in multiple dimensions. Results The relationship of health to its determinants greatly differed between Eastern and Central/Western China. Higher education, higher income level, better life satisfaction, and long-term marriage were significantly associated with better health status among Chinese. In addition, regional healthcare resources were positively associated with the health of residents. As indicated by the hierarchical model with health as dependent variable, in Central/Western China, longest duration of good air quality in spring/summer was positively associated with health (estimated coefficient = 0.067, standard error = 0.026), while the mean Air Quality Index (AQI) in autumn/winter was inversely associated with health (estimated coefficient = −0.082, standard error = 0.031). Good air quality in the current study is defined as daily average AQI less than 35. Conclusions Duration (in days) of acceptable air quality was particularly important for improving public health. Future policies should target increased duration of good air quality while managing air pollution by controlling or decreasing severe air pollution.

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Background-Timothy syndrome (TS) is a rare long-QT syndrome caused by CACNA1C mutations G406R in exon 8A(TS1) and G402S/G406R in exon 8 (TS2). Management of TS is a challenge and prognosis is poor. This study aimed to explore the inheritance pattern and mechanism of an I Na blocker, mexiletine, to improve clinical manifestations in TS. Methods and Results-A 2-year-old Chinese girl with a typical TS1 phenotype underwent candidate gene screening.Qualitative and quantitative cloning sequence and analyses for mosaicism were performed on family members. Therapeutic effects of mexiletine were evaluated using ECG and Holter monitoring. The electrophysiological effect of mexiletine was evaluated in a TS model using rabbit ventricular wedges. The proband with severe syndactyly and delayed language skills was identified harboring a G406R mutation in CACNA1C. Her baseline ECG showed markedly prolonged QTc, 2:1 AV block and macro-T wave alternans. G406R was absent in her mother but expressed in her father's oral mucosa, sperm, and white blood cells, indicating a mosaic carrier. Although asymptomatic, he exhibited mild QTc prolongation (470-490 ms) and syndactyly. Mexiletine shortened QTc from 584 to 515 ms, blunted QT-RR relationship, and abolished 2:1 AV block and T wave alternans in the girl. In in vitro studies, mexiletine inhibited late I Na with IC 50 of 17.6±1.9 µmol/L and attenuated brady-dependent QT prolongation and reduced QT-RR slope in the TS model using BayK 8644. Conclusions-Mexiletine shortened QTc, attenuated QT-RR slope, abolished 2:1 AV block and T wave alternans in a TS1 patient and TS model via inhibition of late I Na . (Circ Arrhythm Electrophysiol. 2013;6:614-622.)Key Words: atrioventricular block ◼ late sodium current ◼ LQT8 ◼ mexiletine ◼ T wave alternans ◼ Timothy syndrome