Expression of CD39 on FoxP3+ T regulatory cells correlates with progression of HBV infection

BACKGROUND: Although it is known that regulatory T cells (Tregs) can suppress the function of effector T cells, and may contribute to impaired immune response, the precise role of Tregs during the course of hepatitis B virus (HBV) infection remains to be elucidated. A newly identified subset of the CD4(+)Foxp3(+ )Tregs, the CD39(+ )Tregs, has been associated with viral infections and autoimmune diseases. Therefore, we hypothesized that this discrete Treg subset may contribute to the chronic infection of HBV. RESULTS: Initial characterization studies of healthy peripheral CD39(+)FoxP3(+)CD4(+ )T cells revealed that the majority were CD45RA(- )Treg cells. Subsequent analysis of HBV-infected patients (38 asymptomatic HBV carriers (AsCs), 37 chronic active hepatitis B (CAH), 29 HBV-associated acute-on-chronic liver failure (ACLF)) and healthy individuals (25 controls) was conducted to assess association with HBV copy number and the liver injury marker alanine aminotransferase (ALT). A higher percentage of CD39(+ )Tregs was detected within the population of FoxP3(+)CD4(+ )T cells in peripheral blood of AsCs patients. Moreover, the percentage of CD39(+ )Tregs was significantly less in CAH and ACLF patients. The increased proportions of circulating CD39(+ )Tregs were positively correlated with serum viral load, but inversely correlated with serum ALT level. CONCLUSION: These findings not only suggest that CD39(+ )Treg cells may be involved in HBV disease progression but also identify CD39(+ )Tregs as a dynamic immune regulatory cell population that may represent a new target of immunomodulatory therapeutic interventions

Effect of polarization sensitivity on ultrasmall SOI-based AWG for FBG sensor interrogation

Polarization sensitivity is an important factor that affects the interrogation of ultrasmall arrayed waveguide grating (AWG) for fiber Bragg grating (FBG) sensor. An ultrasmall 1  ×  8 silicon-on-insulator (SoI) AWG with a core size of less than 530  μm  ×  480  μm is proposed in this study. This ultrasmall SoI AWG exhibits good transmission spectra and high polarization sensitivity. The increased channel numbers and tight structure increase the polarization sensitivity of AWG. Temperature interrogation experiments show that the FBG sensor interrogation is drastically affected when the effect of polarization sensitivity on the ultrasmall AWG is sufficiently large

DFT-Spread Spectrally Overlapped Hybrid OFDM-Digital Filter Multiple Access IMDD PONs

A novel transmission technique—namely, a DFT-spread spectrally overlapped hybrid OFDM–digital filter multiple access (DFMA) PON based on intensity modulation and direct detection (IMDD)—is here proposed by employing the discrete Fourier transform (DFT)-spread technique in each optical network unit (ONU) and the optical line terminal (OLT). Detailed numerical simulations are carried out to identify optimal ONU transceiver parameters and explore their maximum achievable upstream transmission performances on the IMDD PON systems. The results show that the DFT-spread technique in the proposed PON is effective in enhancing the upstream transmission performance to its maximum potential, whilst still maintaining all of the salient features associated with previously reported PONs. Compared with previously reported PONs excluding DFT-spread, a significant peak-to-average power ratio (PAPR) reduction of over 2 dB is achieved, leading to a 1 dB reduction in the optimal signal clipping ratio (CR). As a direct consequence of the PAPR reduction, the proposed PON has excellent tolerance to reduced digital-to-analogue converter/analogue-to-digital converter (DAC/ADC) bit resolution, and can therefore ensure the utilization of a minimum DAC/ADC resolution of only 6 bits at the forward error correction (FEC) limit (1 × 10−3). In addition, the proposed PON can improve the upstream power budget by >1.4 dB and increase the aggregate upstream signal transmission rate by up to 10% without degrading nonlinearity tolerances