Investigation of Broadband S-Band to L-Band Erbium-Doped Fiber Amplifier (EDFA) Module

This chapter presents three sections that describe the broadband S-band to L-band erbium-doped fiber amplifier modules. In the first section, an S-band gain-clamped erbium-doped fiber amplifier (EDFA) module, employing a fiber Bragg grating (FBG) to act as a reflected element for generating a saturated tone injected into the EDFA module by using forward optical feedback method, is proposed. Moreover, the output performance of the gain and noise figure (NF) in the proposed gain-clamped S-band EDFA has been discussed in the wavelength range of 1478–1520 nm. In the second section, we demonstrate experimentally a gain-flattened two-stage erbium-based fiber amplifier (EBFA) module, which is composed of by an erbium-doped waveguide amplifier (EDWA) and a C-band EDFA in serial structure. In an operation range of 1528–1562 nm, the entire gain is larger than 35 dB and the observed NF is between 5.5 and 6.7 dB. Moreover, ±1.1 dB maximum gain variation is also obtained for the input signal power of -25 dBm. Hence, the proposed fiber amplifier not only enhances the gain but also achieves the flatness in the wavelength region. In the final section, a broadband hybrid two-stage fiber amplifier, which is composed by a C-band EDFA and a C-band semiconductor optical amplifier (SOA) in serial scheme, is investigated experimentally. Here, we only use a 3 m long erbium-doped fiber (EDF) serving as a preamplifier to increase the gain and reduce the noise figure. Therefore, the proposed hybrid amplifier achieves a 110 nm effectively amplification of 1500–1610 nm (from S- to L-band). In addition, the output performance of gain and NF in the proposed fiber amplifier has also been discussed

Caffeine treatment disturbs the angiogenesis of zebrafish embryos

[[abstract]]Caffeine is a widely consumed substance that occurs in numerous dietary sources, but teratogenic effects of caffeine intake during embryonic development are still not clear. In the present study, we used the zebrafish as a model to assess caffeine-induced toxicity on embryonic vascular development. A green fluorescent vascular endothelium transgenic line, Tg(fli1:egfp), was utilized for the sensitive detection of vascular development, including vasculo- and angiogenesis. Caffeine-treated embryos showed no defects in vasculogenesis, but revealed dose-dependent (250-350 ppm) developmental defects in intersegmental vessels, dorsal longitudinal anastomotic vessels, and subintestinal vein sprouting. Further, real-time polymerase chain reaction analysis of caffeine-treated embryos showed an upregulation of nrp1a along with a downregulation of sema3aa and sema3c. In conclusion, caffeine treatment induces defects of angiogenesis in zebrafish embryos.[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[countrycodes]]US

Utilization of Reflective Semiconductor Optical Amplifier (RSOA) for Multiwavelength and Wavelength-Tunable Fiber Lasers

In this chapter, there are three sections to demonstrate the reflective semiconductor optical amplifier (RSOA)-based fiber laser architectures for multiwavelength and wavelength-tunable operations. In the first section, we introduce an L-band multiwavelength laser by utilizing a C-band RSOA with a linear cavity, which is produced by a polarization controller (PC), an optical coupler (OCP), and a reflected fiber mirror (RFM). In the proposed RSOA laser scheme, two to seven wavelengths could be lased and created simultaneously in the L-band range, while the RSOA operates at various bias currents

Phosphor-LED-Based Wireless Visible Light Communication (VLC) and Its Applications

In this chapter, we review our recent works on the phosphor white‐light light‐emitting diode (LED)-based wireless visible light communication (VLC) and its applications. This chapter is divided into two sections for introduction. In the first section, in order to enhance the transmission rate in phosphor-LED VLC system, we propose and demonstrate a novel multiband orthogonal-frequency-division-multiplexed (OFDM) modulation format for capacity enhancement. Based on the proposed scheme, various bands of OFDM signals are employed to different LED chips of the LED luminary; it can prevent the power fading and nonlinearity effects of transmission signal. Therefore, the maximum enhanced percentage of VLC data rate is 41.1%. In the second section, we also demonstrate a 71.3–148.4 Mbps phosphor-LED wireless VLC system at the free space transmission distance between 1.4 and 2.1 m. Finally, to understand and demonstrate the real-time LED VLC transmission, a commercial OFDM-based digital signal processor (DSP) is used in the LED transmitting side and client side, respectively. Therefore, the proposed real-time half-duplex VLC system can complete around 70 Mbps downstream and upstream traffic throughputs, in a free space transmission distance of 2 m long for practical in-home illumination and smart city applications

Genetic alterations in Adult T cell leukemia

Human T-cell leukemia virus type 1 (HTLV-1), which infects more than 20 million people worldwide, is known to cause adult T-cell leukemia (ATL). Even those patients treated with intense chemotherapy have a poor prognosis [1]. Although the detailed mechanisms on how HTLV-1 transforms T cells are unclear, it is believed that the viral oncoprotein Tax and the accumulation of somatic alterations lead to ATL [2]. In 2015, Seishi Ogawa and colleague used whole-exome sequencing and whole-genome sequencing to comprehensively analyze ATL genetic alterations [2, 3]. They found that fifty genes are significantly mutated, with 13 genes (PLCG1, PRKCB, CCR4, CARD11, STAT3, TP53, VAV1, TBL1XR1, NOTCH1, GATA3, IRF4, FAS, CCR7) affecting more than 10% of ATL patients [2]. In our previous study, we found Notch1 mutations in 30% of ATL patients leading to reduced Fbw7-mediated degradation and stabilization of the intracellular cleaved form of Notch1 (ICN1). In addition, Notch inhibitors reduced ATL tumor formation in a xenograft model [4]. Since FBXW7 has been reported to be mutated in 6% of human tumors, we hypothesized that the deregulation of FBXW7 can accelerate ATL proliferation and transformation. In my first study, we found that FBXW7 is down-regulated and mutated in ATL patients. In contrast to the tumor suppressor role of FBXW7 wild-type, FBXW7 D510E increased cell proliferation and transformation both in vitro and in an ATL xenograft model [5]. Genome-wide H3K27 me3 accumulation has been observed in ATL patients, which can be explained by Polycomb repressive complex 2 hyperactivation [6]. In addition, EZH2 suppressed Fbxw7 expression via H3K27me3, resulting in Notch activation [7]. We hypothesized that the mutations of epigenetic regulators can reduce the FBXW7 expression in ATL. In my second study, we applied whole-genome next-generation sequencing (NGS) of uncultured freshly isolated ATL samples and identified the presence of mutations in SUZ12, DNMT1, DNMT3A, DNMT3B, TET1, TET2, IDH1, IDH2, MLL, MLL2, MLL3 and MLL4. TET2 was the most frequently mutated gene, occurring in 32 % (10/31) of ATL samples analyzed. Consistent with the previous report, Seishi Ogawa demonstrated hypermethylation in promoter-associated CpG islands in ATL [2]. Since the FBXW7 promoter hypermethylation has been reported [8] and a DNA methyltransferase inhibitor can restore the expression of FBXW7, the correlation of TET2 mutations and FBXW7 down-regulation needs to be further examined. FBXW7α R465C/+ knockin mice increased T-ALL formation when in cooperation with a Notch1 mutation [9]. Mechanically, FBXW7α R465C/+ stabilized c-Myc protein half-life, therefore increasing leukemia-initiating cells (LICs) in FBXW7α R465C/+ knockin mice [9]. In my third study, we confirmed the existence of side populations having both self-renewal and leukemia-renewal capacity and representing cancer stem cells (CSC)/ leukemia-initiating cells (LIC) in ATL cell lines and patient samples. We further show that PI3K and the NOTCH1 signaling pathway have opposite functions on the ATL side population. Constitutive activation of NOTCH1 signaling depletes the pool of side population cells in ATL-derived cell lines. Since Notch1 signaling is deregulated and essential for ATL progression, our results indicate another mechanism to explain how Notch1 signaling is constitutively active in ATL patients, implying a unique therapeutic opportunity to target FBXW7 in the future

A Practical and Secure Stateless Order Preserving Encryption for Outsourced Databases

Order-preserving encryption (OPE) plays an important role in securing outsourced databases. OPE schemes can be either Stateless or Stateful. Stateful schemes can achieve the ideal security of order-preserving encryption, i.e., “reveal no information about the plaintexts besides order.” However, comparing to stateless schemes, stateful schemes require maintaining some state information locally besides encryption keys and the ciphertexts are mutable. On the other hand, stateless schemes only require remembering encryption keys and thus is more efficient. It is a common belief that stateless schemes cannot provide the same level of security as stateful ones because stateless schemes reveal the relative distance among their corresponding plaintext. In real world applications, such security defects may lead to the leakage of statistical and sensitive information, e.g., the data distribution, or even negates the whole encryption. In this paper, we propose a practical and secure stateless order-preserving encryption scheme. With prior knowledge of the data to be encrypted, our scheme can achieve IND-CCPA (INDistinguishability under Committed ordered Chosen Plaintext Attacks) security for static data set. Though the IND-CCPA security can\u27t be met for dynamic data set, our new scheme can still significantly improve the security in real world applications. Along with the encryption scheme, in this paper we also provide methods to eliminate access pattern leakage in communications and thus prevents some common attacks to OPE schemes in practice

A Simple Fiber Bragg Grating-Based Sensor Network Architecture with Self-Protecting and Monitoring Functions

A novel fiber Bragg grating (FBG)-based passive sensor architecture, which can be used to protect the fiber cut and monitor the multiple sensors simultaneously, is proposed and experimentally demonstrated. Here, we employ a wavelength-tunable erbium-doped fiber (EDF) laser scheme with 25 km cavity length acting as the detecting light source in central office (CO). Each FBG sensor, serving as a feedback element, is used in proposed sensor architecture. By tuning the tunable bandpass filter (TBF) placing inside cavity to match the corresponding Bragg wavelength of FBG over the amplification bandwidth, we can retrieve the related wavelength lasing for the FBG sensing and monitoring simultaneously. Moreover, the survivability and capacity of the passive FBG sensor architecture can be also enhanced

Cross-Frequency Coupling and Intelligent Neuromodulation.

Cross-frequency coupling (CFC) reflects (nonlinear) interactions between signals of different frequencies. Evidence from both patient and healthy participant studies suggests that CFC plays an essential role in neuronal computation, interregional interaction, and disease pathophysiology. The present review discusses methodological advances and challenges in the computation of CFC with particular emphasis on potential solutions to spurious coupling, inferring intrinsic rhythms in a targeted frequency band, and causal interferences. We specifically focus on the literature exploring CFC in the context of cognition/memory tasks, sleep, and neurological disorders, such as Alzheimer's disease, epilepsy, and Parkinson's disease. Furthermore, we highlight the implication of CFC in the context and for the optimization of invasive and noninvasive neuromodulation and rehabilitation. Mainly, CFC could support advancing the understanding of the neurophysiology of cognition and motor control, serve as a biomarker for disease symptoms, and leverage the optimization of therapeutic interventions, e.g., closed-loop brain stimulation. Despite the evident advantages of CFC as an investigative and translational tool in neuroscience, further methodological improvements are required to facilitate practical and correct use in cyborg and bionic systems in the field