Application of thiophilic chromatography to deplete serum immunoglobulins in sample preparation for bidimensional electrophoresis

Serum is a typical sample for non-invasive studies in clinical research. Its proteome characterization is challenging, since requires extensive protein depletion. Methods used nowadays for removal of high-abundance proteins are expensive or show quite often a low loading capacity, which has strong repercussions on the number of samples and replicates per analysis.In order to deplete immunoglobulins (Igs) and albumin (HSA) from 1 mL serum samples, we have developed a protocol based on a combination of thiophilic chromatography, not previously used in clinical proteomics, and a HSA-specific resin. Ig/HSA-depleted samples, immunoglobulinome and albuminone were analyzed by 2-DE. Thiophilic chromatography, coupled with HSA-depletion, allows a good 2-DE resolution as well as the visualization of new spots. Moreover, it yields enough protein to evaluate technical variability and facilitate subsequent protein identification. To validate the protocol, we carried out a preliminary comparative study between triplicate Igs/HSA-depleted serum samples from healthy control individuals and recently diagnosed/untreated rheumatoid arthritis (RA) patients. RA patients showed several acute phase proteins, as well as additional serum proteins, differentially and significantly regulated.Therefore, thiophilic chromatography can be used as an efficient and economical method in 2-DE to deplete immunoglobulins from large human serum samples before a more extensive fractioning.     

50 km bidirectional FTTH transmission comparing different PON standards

In this paper, a bidirectional Fiber To The Home (FTTH) is proposed where WDM transmitter is used as a seeding source with wavelength of 1550 nm. The system utilizes a Travelling wave Semiconductor Optical Amplifier (TSOA) with injection current 0.15A. 50 km range FTTH architecture is demonstrated for both downstream and upstream channels. We investigated the impact of different data rates on upstream and downstream data. The BER results show that the performance of our scheme is good for 10 Gbps system for downstream transmission as it accommodates 64 ONUs. From simulation results show the BER of 9.95e-009 is reported at 15 Gbps but only in case of 32 ONUs. Similarly, in case of upstream transmission, Q-Factor of 15.04 dB is reported for 32 ONUs. So this scheme is a practical solution to meet the data rate of the optical links simultaneously in tomorrow's PON access networks.     

基于光环路正交频分多址无源光网络的光拍频噪声避免方案及性能仿真(英文)

在正交频分多址无源光网络上行传输中,不同光网络单元的上行信号如果采用相同波长的不同激光器将会产生光拍频噪声,使得光网络单元的无色性难以实现.本文以正交频分多址无源光网络为研究对象,通过对系统结构的研究和相关公式的推导,分析了信号上行传输中光拍频噪声的产生原因和避免方式.针对下行发送上行载波结合光线路终端相干接收的光拍频噪声避免方案进行了仿真研究.分析了系统的抗色散方案以及色散累积和训练序列长度对系统性能的影响,给出了优化的参数设置,为系统实际应用提供了理论参考.     

The Structure and Function of Paraoxonase-1 and Its Comparison to Paraoxonase-2 and -3

Serum paraoxonase-1 (PON1) is the most studied member of the group of paraoxonases (PONs). This enzyme possesses three enzymatic activities: lactonase, arylesterase, and paraoxonase activity. PON1 and its isoforms play an important role in drug metabolism as well as in the prevention of cardiovascular and neurodegenerative diseases. Although all three members of the PON family have the same origin and very similar amino acid sequences, they have different functions and are found in different locations. PONs exhibit substrate promiscuity, and their true physiological substrates are still not known. However, possible substrates include homocysteine thiolactone, an analogue of natural quorum-sensing molecules, and the recently discovered derivatives of arachidonic acid—bioactive δ-lactones. Directed evolution, site-directed mutagenesis, and kinetic studies provide comprehensive insights into the active site and catalytic mechanism of PON1. However, there is still a whole world of mystery waiting to be discovered, which would elucidate the substrate promiscuity of a group of enzymes that are so similar in their evolution and sequence yet so distinct in their function.     

基于TDM／TDMA的PON及其关键技术

本文介绍基于TDM／TDMA的无源光网络（PON）的概念、基本组成、功能结构及关键技术。     

通过以太无源光网的射频电视传送技术

论述了1550 nm射频电视(CATV)通道与1490 nm数据通道的相互干扰问题。针对1490 nm光波通过光纤中受激拉曼效应对1550 nm光波的非线性串扰和1550 nm光波通过粗波分复用(CWDM)分波器对1490 nm光波的线性串扰提出了理论计算公式,进行了定量分析和计算。结果表明,数据非线性串扰可使射频电视系统低频端的载噪比下跌9 dB;而在常规融锥型粗波分复用分波器情况下,射频电视线性串扰可使数据光接收机的光功率代价达到2.5dB。最后指出了克服串扰的方法,如以太空闲字符扰码和高隔离度粗波分复用等。     

Optimization of passive optical network planning

Network planning problem typically involves large capital investment and can be formulated as an optimization problem where the objective is minimization of the first installed cost. We consider a passive optical network (PON) planning problem based on a residential area in Adana (Turkey). There are four possible primary node locations, twenty possible secondary node locations, and twenty-eight customers. We use genetic algorithm and mathematical modeling techniques to optimize the position of the primary and secondary nodes, their split levels and assigning customers to secondary nodes and secondary nodes to primary nodes under some constraints such as system’s attenuations and technical characteristics of all the equipment.     

Research on OCDMA-based PON monitoring technologies

An optical fiber fault location method based on OCDMA coding is proposed, which may locate branch optical fiber fault at local side. The method expands dynamic range through coding gain without influencing event distinction degree. Through simulation, it indicates that dynamic range of the method may support optical fiber fault detection in PON with branching ratio of 1:16 and transmission distance of 20 km, while the distinction degree is about 10 cm.     

Investigation of wavelength division multiplexing ring network topology to enhance the system capacity

In this paper, we have investigated the wavelength division multiplexed (WDM) system using ring network topology. This network is used to increase the capacity with eight optical add/drop multiplexers (OADMs) by using dispersion compensating fiber and semiconductor optical amplifier (SOA) to achieve a distance up to 1600 km. It is observed that network shows the acceptable results at 15 Gbps data rate with 100 GHz channel spacing. The OADM nodes are also varied to investigate the network performance in the term of BER and Q-factor.     

Investigation of wavelength division multiplexed hybrid ring-tree-star network topology to enhance the system capacity

In this paper, we have investigated wavelength division multiplexed (WDM) hybrid (ring-tree-star) topology. Eight optical add/drop multiplexers (OADMs) are used to make ring structure. The single mode fiber and dispersion compensating fiber and semiconductor optical amplifier (SOA) are employed between each OADM to achieve a maximum. To increase the number of users each OADM node of ring network is connected to star and tree network topology which can accommodate more than 2048 users. Various system parameters (for different channel spacing, different input power signal, different data rates and the fiber length) are varied to investigate the system performance in the term of BER and Q factor.