Resin selection and high-speed coating of optical fibers withUV-curable materials

As a result of the curing properties of UV-curable resins, a selection criterion for UV-curable resins for high-speed fiber coating is proposed. The method is based on specifying two parameters of a UV-curable resin, which designate the Yong's modulus of cured resin. The method was used to coat graded-index fibers with the selected resins and it was demonstrated that the optical loss changes due to the coating process are small. The change of the fiber ribbon was within 0.1 dB/km under temperature changes between -40 °C and +60 °C     

Traffic Analysis of Delayed Delivery Services Considering the Correlation Between Circuit Switching and Message Switching

To improve the ratio of successful calls, a new switching system permitting callers to store messages when the called party is busy or does not answer can be constructed by adding a message storing function to the conventional circuit switching system. The mutual traffic influences exerted by this combination of circuit and message switching systems have not yet been clarified. This paper considers a two-stage loss system traffic model consisting of a circuit switching system that has a message switching system connected to it. The traffic characteristics of this model are analyzed using the nonindependent state transition probability, which depends upon the interacting states of the circuit and message switching system. A method of solving the state equations by determining the state transition probabilities of the message switching system from the state probabilities of the circuit switching system is proposed. Using this method, the mutual traffic influence of the circuit and message switching systems is evaluated.     

Thermal characteristics of jacketed optical fibers with initial imperfection

Thermal characteristics of optical loss and fiber strain in jacketed single-mode optical fibers with initial fiber axis deformation have been examined theoretically and experimentally. Fiber axis deformation due to temperature change is theoretically analyzed by applying buckling theory for a bar on an elastic foundation. Optical loss increase and fiber strain are measured for two kinds of fibers which have different initial fiber axis deformation. Experimental results approximately coincide with values calculated from the theory. It is clarified from these results that the fiber strain due to temperature change is smaller and loss increase at low temperatures is larger for the fiber with larger initial axis deformation. A design method for jacketed single-mode optical fibers to prevent loss increase at low temperatures is given.     

Tensile strength of reinforced fusion-spliced optical fibers

Tensile strength characteristics of reinforced fusion-spliced optical fiber are important to establish a stable optical line in the field. This paper describes theoretical and experimental results on the strength of reinforced fiber. The stripped fiber strengths of fused splice parts and nonheated parts were measured and were found to be different. When a tension is applied to the reinforced fiber, the induced fiber stress is evaluated along its axis. The strength characteristics of reinforced fiber were investigated, based on the stress distribution and the different strengths of fusion-spliced fiber. It is reported that the strength after reinforcement can be predicted and that the strength depends on the adhesive modulus of rigidity. The adhesive design is also presented to obtain necessary strength of reinforced fiber under an allowable failure probability.     

Design and characteristics of multi-hundred-core optical-fiber cable for use in subscriber feeder lines

This paper describes a design method for optical-fiber cable consisting of optical-fiber ribbons encased in loose tubes. The influence of excess fiber length on optical loss in a loose tube is evaluated and the required clearance is obtained. The optimum combination of the clearance and the tube stranding pitch is obtained in order to suppress fiber strain. The tube dimensions are also discussed and are determined to protect fiber ribbons from lateral load. A 600-fiber-structure cable is manufactured according to the obtained design results; the transmission and mechanical performances are confirmed to be excellent.     

Connexin Expression Is Altered in Liver Development of Yotari (dab1 -/-) Mice

Disabled-1 (Dab1) protein is an intracellular adaptor of reelin signaling required for prenatal neuronal migration, as well as postnatal neurotransmission, memory formation and synaptic plasticity. Yotari, an autosomal recessive mutant of the mouse Dab1 gene is recognizable by its premature death, unstable gait and tremor. Previous findings are mostly based on neuronal abnormalities caused by Dab1 deficiency, but the role of the reelin signaling pathway in nonneuronal tissues and organs has not been studied until recently. Hepatocytes, the most abundant cells in the liver, communicate via gap junctions (GJ) are composed of connexins. Cell communication disruption in yotari mice was examined by analyzing the expression of connexins (Cxs): Cx26, Cx32, Cx37, Cx40, Cx43 and Cx45 during liver development at 13.5 and 15.5 gestation days (E13.5 and E15.5). Analyses were performed using immunohistochemistry and fluorescent microscopy, followed by quantification of area percentage covered by positive signal. Data are expressed as a mean ± SD and analyzed by one-way ANOVA. All Cxs examined displayed a significant decrease in yotari compared to wild type (wt) individuals at E13.5. Looking at E15.5 we have similar results with exception of Cx37 showing negligible expression in wt. Channels formation triggered by pathological stimuli, as well as propensity to apoptosis, was studied by measuring the expression of Pannexin1 (Panx1) and Apoptosis-inducing factor (AIF) through developmental stages mentioned above. An increase in Panx1 expression of E15.5 yotari mice, as well as a strong jump of AIF in both phases suggesting that yotari mice are more prone to apoptosis. Our results emphasize the importance of gap junction intercellular communication (GJIC) during liver development and their possible involvement in liver pathology and diagnostics where they can serve as potential biomarkers and drug targets.     

N2733, 1-[3-(3-pyridyl)-acryloyl]-2-pyrrolidinone hydrochloride inhibits LPS-induced TNF-alpha production and improves survival in endotoxemic mice

N2733, 1-[3-(3-pyridyl)-acryloyl]-2-pyrrolidinone hydrochloride, was examined for its effect on TNF-alpha production by human myeloid THP-1 cells stimulated with lipopolysaccharide (LPS). N2733 inhibited LPS-induced release of TNF-alpha from THP-1 cells with an IC50 of 11 microM. N2733 did not affect the cell viability at the concentration of 50 microM or 100 microM. This indicates that N2733 is a potent inhibitor for TNF-alpha production without severe cytotoxicity. N2733 was also studied in two murine endotoxin shock models induced with LPS. One model was DBA/2 mice injected with LPS (5.6 mg/kg, i.v.), which increased the serum level of TNF-alpha within 1 hr. Treatment of these mice with N2733 (100 mg/kg x 2, i.p.) decreased the serum level of TNF-alpha significantly. Another model was DBA/2 mice induced with LPS (30 mg/kg, i.v.), which reduced the survival rate to 30% during 7 days. Administrations of 30 mg/kg and 100 mg/kg N2733 (i.v.) restored the survival rates to 60% and 90% respectively. Our data demonstrate that N2733 inhibits LPS-induced TNF-alpha production, and this response is associated with an improvement in the survival rate of endotoxemic mice.     

Stackable ROADMs for minimizing lightpath interference during upgrade of in-service WDM networks

Bidirectional stackable ROADMs (BS-ROADMs) with 3-port optical add/drop multiplexers (OADMs) have been presented for minimizing the lightpath interference during reconfiguration of the ROADMs. The BS-ROADM is constructed by connecting some modules with different wavelengths, and it is reconfigured by adding new modules required in it. The reconfigurations of the BS-ROADMs are done for upgrading the in-service networks to support newly appeared traffic demand. The experimental results presented in this paper clarify that the BS-ROADM can multiplex and demultiplex the wavelengths successfully without limiting the pass-through wavelengths, providing the wavelength transparent networks. The reconfiguration of an in-service BS-ROADM can be made without influencing any lightpath in the network, and this type of BS-ROADMs is used for premium users. However, while adding a new module in comparatively low-cost BS-ROADMs in-service, the transmission break of some lightpaths might be taken place. The investigated transmission break time was limited within recovery time specified in the service level agreement for best-effort transmission, which has strong cost-effectiveness rather than high QoS. This upgradability of the BS-ROADMs adds more flexibility in coarse wavelength division multiplexing networks in terms of scalability and reconfigurability.