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This paper demonstrates wavelength reused bidirectional transmission for a reflective coherent passive optical network (R-Co-PON). By reusing the downstream optical signal as the upstream optical carrier, the proposed R-Co-PON enhances the optical spectral efficiency. In an experimental demonstration, the proposed R-Co-PON achieved a symmetrical bidirectional transmission rate of 12 Gb/s using a 73-km-long fiber loopback architecture. The experiments confirmed the potential applicability of the proposed system in future optical access networks, particularly those using wavelength-division multiplexing.

Monolayer doping (MLD) has been regarded as the most suitable doping method for future semiconductor devices. MLD based on surface functionalization can be seriously affected by the surface states, including the orientations, crystallinities, and defects. We report for the first time the effect of surface states on boron-MLD (B-MLD) process and discuss the applicability of MLD for a fin structures. Depending on the surface states, the monolayer formation reaction is restricted, which causes more than five-fold differences in the doping level. Therefore, the surface states should be gravely considered before applying MLD and are crucial constraints in the MLD process on non-planar structures that have different surface states depending on its structural position. The B-MLD process on as-cleaned (100) and (110) silicon surfaces provides doping levels of 4.69 × 1020 and 2.48 × 1020 atoms/cm3, respectively. The MLD efficiency on the (110) orientation is degraded by insufficient reaction sites for the hydrosilylation reaction on the monohydride-terminated (110) silicon surface. Additionally, the surface damage interrupts the formation of a dopant-containing monolayer, causing a poor doping level and dose uniformity. Our research provides new insights into the development of wet-chemical doping methods for non-planar devices by studying the effect of surface states on MLD efficiency.

Photo-thermal processing assisted by laser irradiation is proposed as a novel method to control the phase of nickel silicide with reduction in the diffusion of nickel into the silicon substrate. The third harmonics of Nd3+:Y3Al5O12 laser (wavelength, 355 nm) is used for photo-thermal processing. Optical and thermal simulations are performed to obtain an optimum thickness (30 nm) of the nickel film for photo-thermal processing and to predict the temperature profile of the nickel-silicon interface during laser irradiation. It is confirmed that Ni2Si, NiSi and NiSi2 phase are effectively formed at the laser energy densities of 15, 20–40, and 50 mJ/cm2, respectively. We demonstrate that the phases of nickel silicide determined by Raman spectroscopy and X-ray diffraction analyses are in good agreement with those predicted by the heat transfer simulation. In addition, undesirable diffusion of nickel into silicon substrate is considerably reduced by instantaneous photo-thermal processing using the nano-second laser (pulse duration, 6 ns).

In this paper, thermal stability of a one-dimensional metallodielectric photonic crystal (1D MDPhC) structure based on W and SiO2 for thermophotovoltaic systems is reported. The thermal degradation mechanism of the structure, in its operating temperature range, is thoroughly investigated by using energy dispersive spectroscopy (EDS) with transmission electron microscope (TEM) and depth-profiling X-ray photoelectron spectroscopy (XPS). It is found that the structure is entirely destroyed under 1400 K by an inter-diffusion process forming a mixture of W and SiO2 without measurable oxidization of W. But, long-term annealing results in oxidization of W layer even at a lower temperature of 1300 K. During the long-term annealing, oxygen atoms in outside atmosphere are believed to cause oxidation of the upper W layer below the top SiO2 layer. Additionally, delaminated spots are observed over the surface. These thermal behaviors are potential clues to prevent or minimize thermal degradation of the multilayer structure under high temperature operation.

2'-Fucosyllactose (2-FL) is one of most abundant oligosaccharides in human milk, which is involved in many biological functions for infant health. Since 2-FL has a great potential in application to functional food materials and pharmaceuticals, several microbial systems for mass production of 2-FL have been developed in recent years. Microbial production of 2-FL was suggested to be influenced by a number of factors including fucosylation activity of α-1,2-fucosyltransferase. In the present study, the wcfB gene coding for α-1,2-fucosyltransferase from Bacteroides fragilis was screened from eleven candidates of putative α-1,2-fucosyltransferase. Introduction of the wcfB gene allows the lacZ-deleted strain of E. coli expressing the genes for guanosine 5'-diphosphate (GDP)-l-fucose biosynthetic enzymes to produce 2-FL. As a result of fed-batch fermentation, 15.4g/L extracellular concentration of 2-FL with 2-FL yield of 0.858g/g lactose and productivity of 0.530g/L/h were obtained. In addition, the feasibility of industrial production of 2-FL using this microbial system was demonstrated by performing fed-batch fermentation in a 75L bioreactor.

We investigate the effect of the number of laser pulses on the formation of p+/n silicon ultra-shallow junctions during non-melt ultra-violet laser (wavelength, 355 nm) annealing. Through surface peak temperature calculating by COMSOL Multiphysics, the non-melt laser thermal annealing is performed under the energy density of 130 mJ/cm2. We demonstrate that increasing the number of laser pulses without additional pre-annealing is an effective annealing method for achieving good electrical properties and shallow junction depth by analyzing sheet resistance and junction depth profiles. The optimal number of laser pulses is eight for achieving a high degree of activation of dopant without further increase of junction depth. We have also explained the improved electrical characteristics of the samples on the basis of fully recovered crystallinity as revealed by Raman spectroscopy. Thus, it is suggested that controlling the number of laser pulses with moderate energy density is a promising laser annealing method without additional pre-annealing.

Phase diversity of coherent optical communication provides spectrally efficient higher-order modulation for optical communications. However, in-phase/quadrature (IQ) imbalance in coherent optical communication degrades transmission performance by introducing unwanted signal distortions. In a coherent optical orthogonal frequency division multiple access (OFDMA) passive optical network (PON), IQ imbalance-induced signal distortions degrade transmission performance by interferences of mirror subcarriers, inter-symbol interference (ISI), and inter-channel interference (ICI). We propose parallel-channel discrete multitone (DMT) transmission to mitigate transceiver IQ imbalance-induced signal distortions in coherent orthogonal frequency division multiplexing (OFDM) transmissions. We experimentally demonstrate the effectiveness of parallel-channel DMT transmission compared with that of OFDM transmission in the presence of IQ imbalance.

We propose window shaping based inter-band interference suppression technique in multi-band orthogonal frequency division multiple access (MB-OFDMA) based passive optical network (PON) system. Conventional MB-OFDMA and raised-cosine (RC) windowed MB-OFDMA were compared in QPSK transmission and adaptive modulation scenario. The effect of OFDM clipping ratio is analyzed, which is used to mitigate peak to average power ratio (PAPR) problem at the transmitter. Also, the MB-OFDMA based multiple access performance is investigated according to the different roll-off factor of RC window in terms of error vector magnitude (EVM) and effective bit rate. Compared with the conventional MB-OFDMA which is rectangular windowed, the RC-windowed MB-OFDMA shows better performance by suppressed sidelobe which leads to IBI. The maximum effective bit rate of 10 Gbps was achieved for 20 km transmission scenario at optimum roll-off factor, while it was 9 Gbps in the conventional MB-OFDMA transmission.

In this report, a selective interface laser annealing (SILA) process is applied to the atomic-layer-deposited Al2O3 film/p-type silicon interface using an Nd3+: YAG laser with a wave-length of 532 nm. The absorptivity of the laser wavelength confirms a full absorption of the laser power to the Al2O3/Si interface without any loss through the Al2O3 film, which results in a successful selective annealing of the interface. Compared with conventional forming gas annealing (FGA), the SILA is found to build a thinner SiO2 interface layer and lead to a less reduction of capacitance. It is also revealed that the laser-annealed sample exhibits a surface blister density of 31 counts/mm2 which is much lower than the value of 250 counts/mm2 obtained from FGA. The suppression of the surface blister is attributed to the much shorter processing time of lasing (

A new technique, which reduces optical beat interference (OBI) noise in orthogonal frequency division multiple access-passive optical network (OFDMA-PON) links, is proposed. A self-homodyne balanced detection, which uses a single laser for the optical line terminal (OLT) as well as for the optical network unit (ONU), reduces OBI noise and also improves the signal to noise ratio (SNR) of the discrete multi-tone (DMT) signal. The proposed scheme is verified by transmitting quadrature phase shift keying (QPSK)-modulated DMT signal over a 20-km single mode fiber. The optical signal to noise ratio (OSNR), that is required for BER of 10−5, is reduced by 2 dB in the balanced detection compared with a single channel due to the cancellation of OBI noise in conjunction with the local laser.

Objective Suicide by organophosphate insecticide (OPI) poisoning is a major clinical concern (predominantly in developing countries), and 200 000 deaths occur annually worldwide. Red cell distribution width (RDW) has been used to predict outcome in several clinical conditions. Here, we aimed to investigate the relationship between the RDW and 30-day mortality during OPI poisoning. Methods This retrospective analysis was performed between January 2008 and July 2013 in patients admitted to the emergency department after OPI poisoning. A Kaplan-Meier 30-day survival curve was analyzed in patients stratified according to the optimal cut-off point of RDW defined using a receiver operating characteristic (ROC) curve. Multivariate Cox proportional hazards analyses were conducted to determine the independent prognostic factors for 30-day mortality. Results Among 102 patients, 21 died, yielding a mortality of 20.6%. Elevated RDW was significantly associated with early mortality in patients with OPI poisoning. Levels of RDW that exceeded 13.5% (hazard ratio, 2.64; 95% confidence interval [CI], 1.05-6.60) were associated with increased mortality in the multivariate analysis. The area under the ROC curve of RDW was 0.675 (95% CI, 0.522-0.829). Conclusions This study showed that RDW is an independent predictor of 30-day mortality in patients with OPI poisoning.

In this paper, we propose a novel fast adaptive approach that was applied to an OFDM-PON 20-km single fiber loopback transmission system to improve channel performance in term of stabilized BER below 2 × 10−3 and higher throughput beyond 10 Gb/s. The upstream transmission is performed through light source-seeded modulation using 1-GHz RSOA at the ONU. Experimental results indicated that the dynamic rate adaptation algorithm based on greedy Levin–Campello could be an effective solution to mitigate channel instability and data rate degradation caused by the Rayleigh back scattering effect and inefficient resource subcarrier allocation.

We experimentally demonstrate the use of millimeter-wave signal generation by optical carrier suppression (OCS) method using single-drive Mach–Zehnder modulator as a light sources seed for 20 Gb/s WDM-OFDM-PON in 20-km single fiber loopback transmission based on cost-effective RSOA modulation. Practical discrete rate adaptive bit loading algorithm was employed in this colorless ONU system to maximize the achievable bit rate for an average bit error rate (BER) below 2 × 10 −3 .

Cerebrospinal fluid (CSF) may be of valuable for exploring protein markers for the diagnosis of Alzheimer's disease (AD). The prospect of early detection and treatment, to slow progression, holds hope for aging populations with increased average lifespan. The aim of the present study was to investigate candidate CSF biological markers in patients with mild cognitive impairment (MCI) and AD and compare them with age-matched normal control subjects. In this report, we applied proteomics approaches to analyze 60 CSF samples derived from patients with neurodegenerative diseases such as MCI and AD. We classified patients by three groups: normal controls without cognitive dysfunction, MCI and AD. The AD group was subdivided into three groups by clinical severity according to clinical dementia rating (CDR), a well known clinical scale for dementia. We demonstrated a gradual decrease or absent of plasma retinol-binding protein (RBP) and haptoglobin precursor allele 1 in CSF from patients with MCI and AD compared to the age-matched normal subjects. Moreover, expression levels of both RBP and haptoglobin precursor allele 1 were observed to be very high in age-matched normal subjects. In contrast, the RBP and haptoglobin precursor allele 1 were much decreased in the MCI group; those expressions were more weak or absent in AD group, and correlated with disease severity and progression. These findings suggest that the CSF levels of both RBP and haptoglobin precursor allele 1 may be candidate biomarkers for the progression of normal to MCI to AD.