Wavelength conversion, regeneration and tone manipulation using integrated semiconductor lasers and amplifiers

An integrated semiconductor optical amplifier/distributed feedback (SOA/DFB) laser that show promise as a simple all-optical wavelength conversion device together with useful simultaneous functions such as 2R regeneration and the ability to remove a wavelength identifying tone is presented. Wavelength conversion performance at 20Gb/s and 40Gb/s can be obtained with this laser.

All-optical 3R regeneration and format conversion in an integrated SOA/DFB laser

Using a compact, integrated device at 2.488Gb/s, simultaneous NRZ to RZ format conversion and regeneration was achieved. The regenerated signal has a negative BER sensitivity of -1.5dB compared with a data signal transmitted down 101km of standard fiber.

All-optical 3R regeneration and wavelength conversion in an integrated SOA/DFB laser: Experiment and simulation

The simultaneous all optical 3R regeneration and format conversion in a simple, single integrated device was examined. The integrated device consisted of a semiconductor optical fiber (SOA) monolithically integrated with a distributed feedback (DFB) laser. Gain saturation was employed for the transmission of a data signal regenerated all-optically in the laser/amplifier device. The regeneration of the electrically filtered eye diagrams was observed by noise removal and extinction ratio-improvement by the device.

10-Gbits/s all-optical 3R regeneration and format conversion using a gain-switched DFB laser

A strain-compensated multiple quantum well device is used as a DFB laser, this has been optimized for low jitter gain switched operation at 10 GHz. The signal is transmitted down 80 km of standard fiber then amplified, filtered and polarization controlled before being injected into a DFB laser. The purpose of this regeneration process is to gain switch the DFB with the extracted clock signal in order to retime the converted signal. This process also simultaneously converts the input NRZ format to an output RZ data to format and results in a signal whose optical power and extinction ratio are considerably improved by the regeneration process.

Comparative molecular cytogenetic studies in the order Carnivora: mapping chromosomal rearrangements onto the phylogenetic tree

We have made a set of chromosome-specific painting probes for the American mink by degenerate oligonucleotide primed-PCR (DOP-PCR) amplification of flow-sorted chromosomes. The painting probes were used to delimit homologous chromosomal segments among human, red fox, dog, cat and eight species of the family Mustelidae, including the European mink, steppe and forest polecats, least weasel, mountain weasel, Japanese sable, striped polecat, and badger. Based on the results of chromosome painting and G-banding, comparative maps between these species have been established. The integrated map demonstrates a high level of karyotype conservation among mustelid species. Comparative analysis of the conserved chromosomal segments among mustelids and outgroup species revealed 18 putative ancestral autosomal segments that probably represent the ancestral chromosomes, or chromosome arms, in the karyotype of the most recent ancestor of the family Mustelidae. The proposed 2n = 38 ancestral Mustelidae karyotype appears to have been retained in some modern mustelids, e.g., Martes, Lutra, ktonyx, and Vormela. The derivation of the mustelid karyotypes from the putative ancestral state resulted from centric fusions, fissions, the addition of heterochromatic arms, and occasional pericentric inversions. Our results confirm many of the evolutionary conclusions suggested by other data and strengthen the topology of the carnivore phylogenetic tree through the inclusion of genome-wide chromosome rearrangements. Copyright (C) 2002 S. KargerAG, Basel.

Characterization of three fibrinogenolytic enzymes from Chinese green tree viper (Trimeresurus stejnegeri) venom

Rong Gao, Yun Zhang, Qing-Xiong Meng, Wen-Hui Lee, Dong-Sheng Li, Yu-liang Xiong and Wan-Yu Wang. Characterization of three fibrinogenolytic enzymes from Chinese green tree viper (Trimeresurus stejneger ) venom. Toxicon 36, 457-467, 1998.-From the venom of Chinese green tree viper (Trimeresurus stejnegeri), three distinct fibrinogenolytic enzymes: stejnefibrase-l, stejnefibrase-2 and stejnefibrase-3, were purified by gel filtration, ion-exchange chromatography and reverse-phase high-performance chromatograghy (HPLC). SDS-PAGE analysis of those three enzymes showed that they consisted of a single polypeptide chain with mel. wt of -50 000, 31 000 and 32 000, respectively. Like TSV-PA (a specific plasminogen activator) and stejnobin (a fibrinogen-clotting enzyme) purified from the same venom, stejnfibrase-1, -2 and -3 were able to hydrolyze several chromogenic substrate. On the other hand, different from TSV-PA. and stejnobin, stejnefibrase-l, -2 and -3 did not activate plasminogen and did not possess fibrinogen-clotting activity. The three purified enzymes directly degraded fibrinogen to small fragments and rendered it unclottable by thrombin. Stejnefibrase-2 degraded preferentially BE-chain while stejnefibrase-l and -3 cleaved concomitantly Ax and B beta-chains of fibrinogen. None of these proteases degraded the gamma-chain of fibrinogen. When correlated with the loss of clottability of fibrinogen, the most active enzyme was stejnefibrase-l. The activities of the three enzymes were inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-guanidinobenzoate (NPGB), indicating that like TSV-PA and stejnobin, they are venom serine proteases. (C) 1998 Elsevier Science Ltd. All rights reserved.

Decision tree-based context clustering based on cross validation and hierarchical priors

The standard, ad-hoc stopping criteria used in decision tree-based context clustering are known to be sub-optimal and require parameters to be tuned. This paper proposes a new approach for decision tree-based context clustering based on cross validation and hierarchical priors. Combination of cross validation and hierarchical priors within decision tree-based context clustering offers better model selection and more robust parameter estimation than conventional approaches, with no tuning parameters. Experimental results on HMM-based speech synthesis show that the proposed approach achieved significant improvements in naturalness of synthesized speech over the conventional approaches. © 2011 IEEE.