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In this work, we demonstrate a symmetry 28 Gbps/ $\lambda $ on-off keying (OOK) wavelength-division-multiplexing passive optical network (WDM-PON) architecture together with confidential connection between two specific optical network units (ONUs). The presented PON access network also can prevent the Rayleigh backscattering (RB) induced interference noise. Here, to avoid re-deployment of optical fiber and increase cost, a ring-based fiber connection is proposed to connect each ONU for personal information link, when the data connection between two ONUs can be changed arbitrarily. Moreover, the corresponding signal performances of the presented WDM-PON system are also studied and discussed.

In this study, a symmetric polarization-division-multiplexing (PDM) wavelength-division-multiplexing passive optical network (WDM-PON) with fiber to the extension (FTTE) architecture is presented and investigated. The proposed PON can also avoid the Rayleigh backscattering (RB) interference noise. Here, each WDM wavelength can produce 25 Gbit/s on-off keying (OOK) and 10 Gbit/s OOK modulation channels simultaneously in x- and y-polarizations (Polx and Poly) through PDM method for 25 and 105 km single-mode fiber (SMF) transmissions without dispersion compensation. The measured minimal power budget of 25 and 10 Gbit/s downstream and upstream signals are 29 and 35.1 dB and 29.8 and 31.5 dB, respectively, at the forward error correction (FEC) target. Therefore, the proposed PDM WDM-PON architecture can not only offer symmetric 35 Gbit/s downstream and upstream connections by the dual-polarized wavelength, but also can avoid the RB-induced interference noise. In addition, the presented dual-polarized downstream signal also can provide information security in physical layer, when the unauthorized user occupies unlawfully.

In this work, we demonstrate a symmetry 28 Gbps/ $\lambda $ on-off keying (OOK) wavelength-division-multiplexing passive optical network (WDM-PON) architecture together with confidential connection between two specific optical network units (ONUs). The presented PON access network also can prevent the Rayleigh backscattering (RB) induced interference noise. Here, to avoid re-deployment of optical fiber and increase cost, a ring-based fiber connection is proposed to connect each ONU for personal information link, when the data connection between two ONUs can be changed arbitrarily. Moreover, the corresponding signal performances of the presented WDM-PON system are also studied and discussed.

In this paper, we propose a long-reach star-ring-based time- and wavelength-division-multiplexing passive optical network (TWDM-PON) by using fiber- and free space optical (FSO)-protected architecture against fiber breakpoint. Here, the new fiber-based and FSO-based optical network unit (ONU) modules are designed in the PON system to achieve the self-protected operation. Thus, the adjacent ONU is linked to produce the fiber- or FSO-based reconnections. Thus, $4\times 10$ Gbit/s downstream and 10 Gbit/s upstream signals can be reached through 70 km fiber transmission and a length of free space link without signal amplification and dispersion compensation. Moreover, the relationships of splitter ratio and FSO link length in the proposed TWDM access network are also analyzed and discussed.

In the paper, we study a single-longitudinal-mode (SLM) erbium-doped fiber (EDF) ring laser with a switchable single- and dual-wavelength output in C-band scale simultaneously. When a 14 wavelength-division-multiplexing (WDM) multiplexer is placed inside the ring cavity, four tunable single wavelengths and five sets of dual-wavelength with several mode-spacing can be accomplished, respectively. To achieve the selective and stable output characteristic, the suitable adjustment of cavity and birefringent losses are operated. Additionally, the laser characteristics of output wavelength, detected power, and optical signal to noise ratio (OSNR) have also been discussed.

In the paper, we exhibit and demonstrate a stable erbium-doped fiber (EDF) multiple-ring laser with self-injection of Rayleigh scattering (RB). Here, utilizing the Vernier effect based on multiple-ring scheme and the optical RB injection, a stable single-longitudinal-mode (SLM) operation and narrow linewidth output can be achieved over an available tuning bandwidth of 1524.0–1577.0 nm by using a commercial C-band EDF gain medium. Moreover, we also execute and discuss the output characteristic of power, lasing linewidth, optical signal to noise ratio (OSNR), tunability and stability in the demonstrated fiber laser.

In the work, a self-injected erbium-doped fiber (EDF) dual-fiber-ring (DFR) laser configuration for wavelength-adjustable and stable single-longitudinal-mode (SLM) output is experimentally demonstrated. The tuning wavelength bandwidth can be accomplished from 1519.0 to 1588.0 nm covering both C- and L-bands based on the DFR scheme and self-injected loop, when a C-band EDF is exploited as the gain medium. In addition, the output power, laser linewidth and optical signal to noise ratio (OSNR) of the EDF laser are also studied and discussed. Thus, the designed EDF laser not only can narrow the wavelength linewidth for SLM oscillation, but also can broaden the available tuning bandwidth.

To accomplish single-longitudinal-mode (SLM) output and continuous wavelength selection, an erbium-doped fiber (EDF) quad-ring (QR) laser is presented and experimentally examined. The designed QR scheme can induce a mode-filter effect to compress dense multi-mode oscillation, narrow laser linewidth and flatten power output simultaneously. Hence, the attained optical signal to noise ratio (OSNR) and output power are between in an obtainable tunability bandwidth of 1524.0 to 1569.0 nm. In addition, the observed output characteristics of stability, flatness and linewidth of the fiber laser are also investigated and discussed.

In this study, we present and experimentally demonstrate an erbium-doped fiber (EDF) quad-fiber-ring (QFR) laser with selectable and flat single-longitudinal-mode (SLM) wavelength output. The designed QFR scheme not only can suppress dense multi-mode oscillation, but also can broaden and flatten the output wavelength covering C- and part of L-bands over a bandwidth from 1519.0 to 1579.0 nm when using a C-band EDF as gain medium. Additionally, the output power, optical signal to signal ratio (OSNR), linewidth, stability and tunability of the proposed EDF laser are also discussed.

Starchy grain is usually supplemented to diets containing low-quality forage to provide sufficient energy for ruminant animals. Ruminal degradation of grain starch mainly depends on the hydrolysis of the endosperm, which may be variable among grain sources. This study was conducted to investigate the influence of endosperm structure of wheat and corn on in vitro rumen fermentation and nitrogen (N) utilization of rice straw. The 3×4 factorial design included three ratios of concentrate to forage (35:65, 50:50 and 65:35) and four ratios of wheat to corn starch (20:80, 40:60, 60:40 and 80:20). The endosperm structure was detected by scanning electronic microscopy and a confocal laser scanning microscopic. An in vitro gas test was performed to evaluate the rumen fermentation characteristics and N utilization. Starch granules were embedded in the starch–protein matrix in corn, but more granules were separated from the matrix in the wheat endosperm. With the increasing ratio of wheat, rate and extent of gas production, total volatile fatty acids, and ammonia N increased linearly (P

Rationale: Plexiform fibromyxoma (PF) is an extremely rare mesenchymal tumor of the stomach, and its radiological findings have not been well described. Here, we analyzed the imaging features of a case of PF. To our knowledge, this is a rare reported case with a remarkable cystic change in the imaging literature. Patient concerns: A previously healthy 50-year-old woman presented with a 1-day history of abdominal pain. Then, she underwent computed tomography (CT) and magnetic resonance imaging (MRI). A cystic-solid well-circumscribed extraluminal mass was located in the posterior wall of the gastric upper body. The solid portion appeared as heterogeneous attenuation/intensity with progressive enhancement while the cystic region had no enhancement. Diagnoses: The potential for malignancy could not be excluded. Interventions: Laparoscopic partial gastric resection was performed. Outcomes: Based on pathological findings, a diagnosis of PF was made. The patient was alive without any recurrence or metastasis of the tumor after 2 years of follow-up. Lessons: As far as we know, a gastric PF with a remarkable cystic change has never been reported. Additionally, the tumor exhibited a progressive enhancement pattern which is a characteristic radiographic feature in our case. Our report may help increase the awareness of this rare but important new disease entity.

Primary small cell carcinoma of the ureter is an extremely rare disease, only several cases have been reported worldwide so far. We report a 70-year-old woman who was examined with intravenous urography and abdominal computed tomography and was diagnosed as small cell carcinoma confirmed by pathology. We describe and discuss the urography and computed tomography findings of this case.

To investigate the feasibility of a dual-input two-compartment tracer kinetic model for evaluating tumorous microvascular properties in advanced hepatocellular carcinoma (HCC).From January 2014 to April 2015, we prospectively measured and analyzed pharmacokinetic parameters [transfer constant (Ktrans), plasma flow (Fp), permeability surface area product (PS), efflux rate constant (kep), extravascular extracellular space volume ratio (ve), blood plasma volume ratio (vp), and hepatic perfusion index (HPI)] using dual-input two-compartment tracer kinetic models [a dual-input extended Tofts model and a dual-input 2-compartment exchange model (2CXM)] in 28 consecutive HCC patients. A well-known consensus that HCC is a hypervascular tumor supplied by the hepatic artery and the portal vein was used as a reference standard. A paired Student's t-test and a nonparametric paired Wilcoxon rank sum test were used to compare the equivalent pharmacokinetic parameters derived from the two models, and Pearson correlation analysis was also applied to observe the correlations among all equivalent parameters. The tumor size and pharmacokinetic parameters were tested by Pearson correlation analysis, while correlations among stage, tumor size and all pharmacokinetic parameters were assessed by Spearman correlation analysis.The Fp value was greater than the PS value (FP = 1.07 mL/mL per minute, PS = 0.19 mL/mL per minute) in the dual-input 2CXM; HPI was 0.66 and 0.63 in the dual-input extended Tofts model and the dual-input 2CXM, respectively. There were no significant differences in the kep, vp, or HPI between the dual-input extended Tofts model and the dual-input 2CXM (P = 0.524, 0.569, and 0.622, respectively). All equivalent pharmacokinetic parameters, except for ve, were correlated in the two dual-input two-compartment pharmacokinetic models; both Fp and PS in the dual-input 2CXM were correlated with Ktrans derived from the dual-input extended Tofts model (P = 0.002, r = 0.566; P = 0.002, r = 0.570); kep, vp, and HPI between the two kinetic models were positively correlated (P = 0.001, r = 0.594; P = 0.0001, r = 0.686; P = 0.04, r = 0.391, respectively). In the dual input extended Tofts model, ve was significantly less than that in the dual input 2CXM (P = 0.004), and no significant correlation was seen between the two tracer kinetic models (P = 0.156, r = 0.276). Neither tumor size nor tumor stage was significantly correlated with any of the pharmacokinetic parameters obtained from the two models (P0.05).A dual-input two-compartment pharmacokinetic model (a dual-input extended Tofts model and a dual-input 2CXM) can be used in assessing the microvascular physiopathological properties before the treatment of advanced HCC. The dual-input extended Tofts model may be more stable in measuring the ve; however, the dual-input 2CXM may be more detailed and accurate in measuring microvascular permeability.

Aim To evaluate the reliability and utility of preoperative perforator planning using computed tomography angiography (CTA) in anterolateral thigh perforator flap (ALTPF) transplantation. Materials and methods Thirty-two consecutive patients who underwent extremity reconstruction using the ALTPF were retrospectively reviewed from 2008 to 2012. These patients were divided into two groups. In group I (n = 16), suitable perforators were designed based on four criteria using CTA. These were used for the operation and compared with the intraoperative findings. In group II (n = 16), all patients underwent operation using conventional methods without preoperative perforator planning. The surgical results of all patients were evaluated for flap complications, alteration of the donor site, donor site morbidity, and the incidence of reoperation. Results In group I, there were no statistically significant differences between the parameters, including the calibre and location of the origin (perpendicular and horizontal distance from the origin of the perforator to both the superior lateral border of the patella and the lateral region of the thigh) of all planning perforators and the operative measurement results (p-values were 0.3, 0.422, and 0.129, respectively). The types were consistent with the operative findings; the rate of the septocutaneous type was 31.25% (5/16), and the rate of the musculocutaneous type was 68.75% (11/16). The use of preoperative perforator planning in group I was associated with a significant reduction in flap complications (p = 0.009) compared with group II. There was no difference between the two groups in alteration of the donor site, donor site morbidity, or the incidence of reoperation (p-values were 0.225, 0.225, and 0.33, respectively). Conclusion Preoperative perforator planning using CTA in ALTPF transplantation is a reliable and useful method resulting in safer operation with optimal outcome.

Primary gastric plasmacytoma (GP) is a rare extramedullary plasmacytoma with clinical and imaging features that are common among other gastric tumors, such as gastric adenocarcinomas, gastric stromal tumors, and lymphomas. Here, we present a histologically confirmed case of primary GP examined with biphasic computed tomography (CT), magnetic resonance imaging (MRI), and endosonography. A well-circumscribed extraluminal mass appearing as homogeneous attenuation/intensity with gradual enhancement was identified on biphasic enhancement CT and MRI. This mass was hyperintense on diffusion-weighted imaging and hypointense on the apparent diffusion coefficient map, implying that water diffusion in the mass was restricted. In addition, endosonography indicated a low echogenic mass in the gastric wall. These imaging findings increase the available knowledge about imaging of this disease and provide valuable information for differentiating primary GP from common gastric tumors.

Histiocytic sarcoma (HS) is a rare malignant neoplasm that originates from a histiocytic hematopoietic lineage characterized by histiocytic differentiation and its corresponding immunophenotypic features. We herein reported a case of primary HS of the stomach which was confirmed through histopathologic examination and immunohistochemical staining. A 52-year-old woman presented with progressive difficulty in feeding and dull pain in the epigastric region. Gastroscopy, endoscopic ultrasonography, double contrast examination, and computed tomography revealed a mass located on the posterior wall of fundus and lesser curvature of the stomach. Microscopically, the cytoplasm of the tumor cells was abundant and eosinophilic. Immunohistochemical staining revealed that the tumor cells were positive for CD45RO and CD68. It is difficult to differentiate HS of stomach from other gastric malignancies by radiological evaluation alone. However, HS may be considered when a protruding and ulcerated mass in stomach shows heterogeneous hypervascular features. To the best of our knowledge, this is the first report in English language literature that emphasizes the imaging findings of human gastric HS.