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Background: Incident fatty liver increases the risk of non-alcoholic fatty liver disease (NAFLD), which may lead to end-stage liver diseases, and increase the risk of cardiovascular disease and diabetes. For its prevention, modeling the natural history of fatty liver is useful to demonstrate which lifestyle-related risk factors (e.g. body mass index and cholesterol) play the greatest role in the life-course of fatty liver., Methods: Model predictors and their predictive algorithms were determined by prospective regression analyses using 5-year data from approximately 2000 Japanese men aged 20-69 years. The participants underwent health examinations and completed questionnaires on their lifestyle behaviors annually from 2012 to 2016. The life-course of fatty liver was simulated based on this participant data using Monte Carlo simulation methods. Sensitivity analyses were performed. The validity of the model was discussed., Results: The body mass index (BMI) and low-density/high-density lipoprotein cholesterol (LDL-C/HDL-C) ratio significantly aided in predicting incident fatty liver. When the natural history of fatty liver was simulated using the data of participants aged 30-39 years, the prevalence increased from 20% to 32% at 40-59 years before decreasing to 24% at 70-79 years. When annual updates of BMI and LDL-C/HDL-C ratio decreased/increased by 1%, the peak prevalence of fatty liver (32%) changed by -8.0/10.7% and -1.6/1.4%, respectively., Conclusions: We modeled the natural history of fatty liver for adult Japanese men. The model includes BMI and LDL‒C/HDL‒C ratio, which played a significant role in predicting the presence of fatty liver. Specifically, annual changes in BMI of individuals more strongly affected the life‒course of fatty liver than those in the LDL-C/HDL-C ratio. Sustainable BMI control for individuals may be the most effective option for preventing fatty liver in a population., Competing Interests: MA, SI, MM and MK have no competing interests. KA is an employee of Fujikura Ltd., but had no control over the data collection or analysis of this work. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

With the capacity limits of standard single-mode optical fiber fast approaching, new technologies such as space-division multiplexing are required to avoid an Internet capacity crunch. Few-mode multicore fiber (FM-MCF) could allow for a two orders of magnitude increase in capacity by using the individual spatial modes in the different cores as unique data channels. We report the realization of a monolithic mode-selective few-mode multicore fiber multiplexer capable of addressing the individual modes of such a fiber. These compact multiplexers operate across the S + C + L telecommunications bands and were inscribed into a photonic chip using ultrafast laser inscription. They allow for the simultaneous multiplexing of the LP 01 , LP 11a and LP 11b modes of all cores in a 3-mode, 4-core fiber with excellent mode extinction ratios and low insertion losses. The devices are scalable to more modes and cores and therefore could represent an enabling technology for practical ultra-high capacity dense space-division multiplexing.

An optimized two-mode optical fiber (TMF) with the graded index (GI) profile is designed and fabricated. We clarify an appropriate region of GI-TMF satisfying DMD = 0 ps/km, the large effective area A(eff), and the low bending loss for LP(11) at 1550 nm. According to our fiber design, GI-TMF is successfully fabricated to have the large effective area A(eff) of 150 μm(2) for LP(01) mode, and low DMD below 36 ps/km including zero in the C-band. We expect that our design GI-TMF is suitable for MDM and can reduce MIMO-DSP complexity.

The feature of a multicore fiber with one-ring structure is theoretically analyzed and experimentally demonstrated. The one-ring structure overcomes the issues of the hexagonal close-pack structure. The possibility of 10-core fiber with Aeff of 110 μm(2) and 12-core fiber with Aeff of 80 μm(2) is theoretically presented. The fabricated 12-core fibers based on the simulation results realized Aeff of 80 μm(2) and crosstalk less than -40 dB at 1550 nm after 100-km propagation. The MCF with the number of core larger than seven and the small crosstalk was demonstrated for the first time.

Characteristics of few-mode multi-core fiber (FM-MCF) were numerically analyzed and experimentally confirmed. The cores of FM-MCF were designed to support transmission of LP(01) and LP(11) modes from the point of bending loss of LP(11) and LP(21) modes. Inter-core crosstalk between LP(11) mode was calculated to determine core pitch of fibers. It was confirmed that the fabricated fibers was two-mode transmission over C-band and L-band with the effective area of LP(01) mode of about 110 μm(2) at 1550 nm. The crosstalk of the fibers was estimated to be smaller than -30 dB at 1550 nm after 100-km propagation. The crosstalk dependence on wavelength was also measured and matched well with the simulated results.

An effectively single-mode all-solid photonic bandgap fiber with large effective area and low bending loss for compact high-power all-fiber lasers is fully investigated. The pitch dependencies of effective area, bending loss, and effectively single-mode operation are discussed numerically and experimentally. The calculation results indicate that an effectively single-mode all-solid photonic bandgap fiber with an effective area of more than 500 μm(2) and a bending loss of less than 0.1 dB/m at a bending radius of 10 cm can be realized by choosing optimum fiber parameters. In a fabricated effectively single-mode all-solid photonic bandgap fiber with 48.0 μm core, the effective area of 712 μm(2), the effectively single-mode operation, and the bending loss of less than 0.1 dB/m at a bending radius of 10 cm are achieved simultaneously at 1064 nm.

A large-mode-area all-solid photonic bandgap fiber with a seven-cell core and five high-index rod rings is investigated. Numerical simulations show that an effective area of more than 500 μm(2), a bending loss of less than 0.1 dB/m at a bending radius of 10 cm and effectively single-mode operation can be achieved simultaneously. A core diameter of 44.8 μm and an effective area of 650 μm(2) at 1064 nm are achieved in a fabricated fiber. Bending loss at 1064 nm is 0.09 dB/m at a bending radius of 7 cm. Effectively single-mode operation is also realized at a bending radius of 10 cm., (© 2012 Optical Society of America)

The cladding thickness of trench-assisted multi-core fibers was theoretically and experimentally investigated in terms of excess losses of outer cores. No significant micro-bending loss increase was observed on multi-core fibers with the cladding thickness of about 30 µm. The tolerance for the micro-bending loss of a multi-core fiber is larger than that of the single core fiber. However, the cladding thickness will be limited by the occurrence of the excess loss on outer cores. The reduction of cladding thickness is probably limited around 40 µm in terms of the excess loss. The multi-core fiber with an effective area of 110 µm(2) at 1.55 µm and 181-µm cladding diameter was realized without any excess loss., (© 2011 Optical Society of America)

A multicore fiber with two-pitch layout is proposed to overcome the trade-off between core number and a cladding diameter of a standard hexagonal layout with a single-core pitch. A fabricated ten-core fiber simultaneously realizes effective area of about 120 μm(2) at 1550 nm, small crosstalk, and cladding diameter of 204 μm. The crosstalk between the center core and outer cores is about 30 dB smaller than that between outer cores. The small crosstalk of the center core would help to keep the transmission quality of the center core at the same level as that of the outer cores., (© 2011 Optical Society of America)

New design of optical waveguides is presented to synthesize Bragg grating waveguides without inducing birefringence. In the design, waveguide core has a thin trench on the top surface of the core and width of the trench is modulated concurrently with width modulation of the waveguide core. Effective refractive index profiles in Bragg grating waveguides are obtained by a differential inverse scattering algorithm and converted to waveguide width profiles by using the new core design. This procedure allows design of non-birefringent Bragg grating waveguides on planar substrate. The method is applied to the design of chromatic dispersion compensators. For characterization of Bragg grating waveguides, analysis based on short-time Fourier transform of Bragg grating response waveforms is presented.

We have investigated the relationship between the energy levels of an emissive layer and the modulation rate of organic light-emitting diodes (OLEDs) based on a distyrylbenzene derivative, 1,4-bis[2-[4-[N,N-di(p-tolyl)amino]phenyl]vinyl]benzene (DSB). By utilizing DSB as an emitting material, a high modulation rate can be realized because of the short fluorescence lifetime of 0.2 ns of DSB. Furthermore, we also found that an energy gap between an emissive layer and an adjacent organic layer is an important parameter to improve modulation rate. DSB-doped 4,4-bis(2,2-ditolylvinyl)biphenyl is the best combination of all the organic materials used in this study, and the fastest cutoff frequency of 10 MHz has been achieved for the OLED in spite of the large emitting area of 1 mm(2).

We have demonstrated a short fluorescence lifetime of the substituted phenyl/vinyl compound, 1,4-bis[2-[4-[N,N-di(p-tolyl)amino]phenyl]vinyl]benzene (DSB). The fluorescence lifetime of the 0.5 mol.% DSB-doped 4,4'-bis(9-carbazolyl)biphenyl film is 1.2 ns, which is desirable for organic light-emitting diode (OLED) light sources for optical interconnect applications. We have also examined frequency dependences on the electroluminescence (EL) intensity of the OLED and the photoluminescence (PL) intensity of the DSB film. The -3 dB cutoff frequency of the EL intensity is about 3 MHz for the optimized device, and the -3dB cutoff frequency of the PL intensity is about 160 MHz for the optically pumping DSB film.

A warm-white light-emitting diode (LED) without blending of different kinds of phosphors is demonstrated. An approach that consists of a blue LED chip and a wavelength-conversion phosphor is carried out. The phosphor is a newly developed yellowish orange CaEuSiAlON ceramic phosphor with high efficiency. The CIE1931 chromaticity coordinates (x, y) are (0.458, 0.414), the color temperature is 2750 K, and the luminous efficacy of this LED is 25.9 lm/W at room temperature and with a forward-bias current of 20 mA. The chromaticity of the assembled LED is more thermally stable than that of a LED with a conventional oxide phosphor (YAG:Ce) because of the better thermal stability of the oxynitride phosphor.