Bypass/backup-link switchable coherent point-to-multipoint configured WDM-PON system with shared protection.

A disaster-resistant, point-to-multipoint network configuration that connects distributed optical terminals to a centralized optical terminal, through an exclusive fiber link, is required in edge computing strategies such as 5G, IoT applications, ultrareliable and low latency applications, high-performance content delivery, artificial intelligence applications, and hyperconverged infrastructure. Therefore, we introduce a shared link orientation that fully connects the distributed optical terminal side to the centralized optical terminal side represented by the conventional optical access network. We also propose a method that switches a fully-coupled or half-split network to the centralized optical terminal on the optical switch aggregation station side. We report a verification experiment on the proposed method to confirm the operation of wavelength conversion/optical path switching when a link failure occurs, achieving < 2 dB penalty with small back reflection in wavelength collision-free secondary link transmissions with primary link failure. The unique point of this research is that the centralized optical terminal can easily change from the link-occupancy-oriented network to the link-sharing-oriented network. This work will lead to development of a novel disaster-resistant network configuration for wavelength division multiplexing-based coherent passive optical network systems.

Learning-based digital back propagation to compensate for fiber nonlinearity considering self-phase and cross-phase modulation for wavelength-division multiplexed systems.

We propose a learning-based digital back propagation (LDBP) technique that addresses self-phase modulation (SPM) and cross-phase modulation (XPM) of a wavelength-division multiplexed (WDM) optical signal. The LDBP has a structure defined for each of the individual channels of a WDM signal, and connections between the channels address the XPM to effectively compensate for nonlinear waveform distortion of the signal in long-distance optical transmission systems. We attempt to optimize the limited number of parameters used in the structure such as the dispersion, nonlinear coefficient, and walkoff parameter to compensate for the nonlinear phase shift induced by the XPM. We derive equations to update the parameters through an iterative process based on the stochastic gradient descent algorithm. We verify the effectiveness of the proposed LDBP technique through a transmission experiment that uses an 11-channel WDM, 32-Gbaud, dual-polarization 16 quadrature amplitude modulation (QAM), and probabilistically shaped (PS) 64QAM signals. With the focus on the LDBP with a 1-step/span configuration, we operate the learning process using the received 16QAM signal in the experiment. We confirmed the successful convergence of particular parameters of the model of the transmission line after the developed learning procedure. We apply the LDBP with fixed optimized parameters to the received waveforms of the PS-64QAM signals and compare the performance with some DBPs. We observed that the proposed LDBP technique that considers XPM with 1-step/span configuration exhibits the best performance in compensating for nonlinear waveform distortion. Additionally, the learning process is effective for the case considering both SPM and XPM compared with the case of SPM only. Finally, we investigate the computational complexity of the LDBP and reveal that the total calculation cost is of the same order as that of a conventional DBP considering only SPM with a 2-step/span configuration.

Polarization-insensitive local-oscillator-carrier loopback modulation for a cost-effective and high-port-count wavelength-routing optical switch.

A wavelength-routing optical switch uses a wavelength-tunable laser at each input port, and this transmitter implements output port selection by tuning the wavelength that is associated with each output port. With coherent transmission, loopback modulation of a local oscillator (LO) carrier generated at the output port can eliminate the need for a wavelength-tunable laser. However, loopback modulation can be unstable since the power fluctuates because fiber traversal by the light creates polarization rotation. Here, we propose a simple polarization-alignment circuit and verify its effectiveness in creating a high-port-count optical switch system. The proposed circuit consists of passive components and aligns the polarization state of the supplied LO carrier to be linearly polarized along the x-direction of a TE-input dual-polarization (DP) IQ modulator. The circuit is shown to yield stable modulation with Q-variation of less than 0.8 dB, regardless of any birefringence along the transmission path. The proposal's effectiveness is verified in optical switch system experiments with DP-QPSK signals; 1,856 × 1,856 switch scale is achieved with loopback modulation.

Early Enteral Nutrition with High-Protein Whey Peptide Digestive Nutrients May Improve Prognosis in Subarachnoid Hemorrhage Patients.

Background and Objectives: Nutritional management in patients with subarachnoid hemorrhage (SAH) during the acute phase is important; however, there is no proper evidence or recommendations on the appropriate nutrients for early enteral nutrition. This study compared the influence the two different tube-feeding liquid diets for early enteral nutrition might have on the prognosis of patients with SAH. Materials and Methods: In a seven-year period, this single-center retrospective study included 245 patients with aneurysmal SAH who underwent craniotomy and aneurysm neck clipping and received enteral nutrition. The patients were divided into two groups according to the nutrient received: (1) high-protein whey peptide oligomeric formula diet (oligomeric group, 109 patients); and (2) high eicosapentaenoic acid-containing polymeric formula diet (polymeric group, 136 patients). The modified Rankin Scale (mRS) score at discharge was evaluated as the primary outcome. The presence or absence of diarrhea (watery stool and mushy stool) during the period from initiation of enteral nutrition to discharge from the stroke unit was also evaluated. Results: There were no significant differences in patient characteristics between groups. The time until initiation of enteral feeding in the oligomeric and polymeric groups was 2.8 ± 2.3 and 2.9 ± 2.2 days, respectively. The proportion of patients with mRS scores of 0-1 was significantly higher in the oligomeric group (25.7%) than in the polymeric group (14.7%) (p = 0.036), while the incidence of watery stool was significantly lower in the oligomeric group (15.8% to 34.3% in the polymeric group) (p = 0.003). Multivariate analyses confirmed that the oligomeric diet and the presence or absence of diarrhea significantly affected the mRS scores. Conclusions: The adoption of early enteral nutrition with high-protein whey peptide digestive nutrients might be associated with superior mRS scores at discharge and decreased diarrhea in patients with SA, indicating that the choice of nutrients might affect the outcome and prognosis.

Design and verification of a LO bank enabled by fixed-wavelength lasers and fast tunable silicon ring filters for creating large scale optical switches.

The fast and widely tunable wavelength bank is a key enabler in creating wavelength-routing optical switches that do not use fast wavelength tunable lasers. A cost-effective design criterion needs to be developed before it can be applied to intra data center networks. In this paper, we develop a systematic method for designing a wavelength bank that yields high port-count and fast wavelength-routing optical switches for intra data center application. The wavelength bank is created with fixed-wavelength laser sources and wavelength-tunable filters with rapid wavelength selectivity. To optimize the optical switching system that uses the wavelength bank for supplying local oscillator (LO) lights for coherent detection, various parameters are analyzed, including effective bandwidth, laser output power, loss distribution, splitter port count, and optical amplifier gain. We carry out numerical simulations for optimizing the tradeoff between system performance and cost. To verify the designed wavelength bank, a silicon ring filter is newly fabricated with an average fiber-to-fiber insertion loss of 5.3 dB over a 22-nm bandwidth. Using 256-Gb/s DP-QPSK signals, experiments demonstrate a 1,024×1,024 optical switch that uses a fabricated silicon ring filter. The effectiveness of the scalable and fast-tunable LO bank is verified by achieving 262.1-Tb/s switch throughput with switching time under 18 µs.

Scalable two- and three-dimensional optical labels generated by 128-port encoder/decoder for optical packet switching.

This paper deals with massive number of optical code (OC) label generation and recognition for scalable optical packet switching (OPS) networks. In order to expand the system scalability of code label processing, we develop a record port count 128 x 128 optical encoder/decoder (E/D) and propose a novel three-dimensional (3-D) optical label combining code label with wavelength and polarization. In the experiment, we conduct a proof-of-concept demonstration of 4-code x 2-wavelength x 2-polarization and validate that the 3-D labeling scheme can consequently increase the available number of code label up to more than 1,000 labels. Real-time labeling performance using a field programmable gate array (FPGA)-based processor and crosstalk influence at an optical switch are also experimentally evaluated.

A rare case of fibrohistiocytic hepatic inflammatory pseudotumor with cholecystocholangitis showing positive IgG4 staining.

Inflammatory pseudotumor (IPT) is a rare benign mass characterized by infiltration of inflammatory cells and proliferation of fibrous tissues. Consistent with increasing knowledge about IgG4-related disease (RD), it has been implicated in the etiology of hepatic IPT, which is pathologically classified into two categories with respect to the proportion of IgG4-positive plasma cells: fibrohistiocytic- and lymphoplasmacytic-type. A 66-year-old man was admitted for treatment of cholecystocholangitis. Incidentally, abdominal computed tomography (CT) revealed an ambiguous low-density mass within segment 4 (S4) of the liver. Magnetic resonance imaging (MRI) showed the typical images of hepatic IPT within S4. Together with CT and MRI imaging, we suspected hepatic IPT, and had the opportunity to biopsy the S4 lesion during surgery for cholecystitis. Histopathological examination of liver tissue showed diffuse fibrous tissues, dense lymphoplasmacytic infiltration, and obliterative phlebitis with no evidence of malignancy. Despite infiltration of IgG4-positive plasma cells, these histological findings corresponded with fibrohistiocytic-type hepatic IPT. Similarly, in the resected gallbladder, relatively abundant IgG4-positive cells were observed, but not entirely consistent with IgG4-RD criteria. Although IgG4 immunostaining can be useful for the classification of hepatic IPT, the present histological tissues were borderline condition defined by IgG4-RD criteria. This rare case of hepatic IPT suggests a future focus on the borderline histological features of IgG4-RD.

[A clinical study of admitted the review of cases of food-dependent exercise-induced anaphylaxis].

BACKGROUND: Food-dependent exercise-induced anaphylaxis (FDEIA) is characterized by anaphylactic symptoms after eating certain foods, followed by exercise. As we examine more patients who have pollinosis, we have more opportunities to see allergic disease such as FDEIA, OAS, and so on. METHODS: We performed a retrospective analysis of six cases, diagnosed FDEIA for this three years. RESULTS: Of six cases, the ages are 8 to 47 years old, and the trigger allergens were wheat, shrimp, and grapefruit. The trigger exercises were running, volleyball, as well as taking a bath. In four cases, the patients had history of allergic disease such as atopic dermatitis, allergic rhinitis, and so on. In two cases of wheat-dependent exercise-induced anaphylaxis, the IgE levels for omega5-gliadin (a major wheat allergen) in a RAST were positive. CONCLUSION: Of six cases diagnosed FDEIA, the trigger allergens were wheat, shrimp, and grapefruit. In cases of wheat-dependent exercise-induced anaphylaxis, the IgE levels for omega5-gliadin in a RAST were positive. After the food allergen has been identified, we advised strict restrictions on ingestion of trigger allergens in the case of shrimp and grapefruit, and on any exercise after eating foods containing wheat flour in the case of wheat.