Efficacy of Hepatitis B Vaccination in Under Five-Year-Old Children in Iran: A Systematic Review and Meta-Analysis Study

Context: Hepatitis B viral infection, specially in children, is an unsolved global health issue. National and international vaccination programs, as the main means to prevent this infection, have been operating for years. This meta-analysis study was launched to investigate the vaccination efficacy in under five-year-old children in Iran. Evidence Acquisition: In this research, all national databases including, SID, Magiran, Iran medex, Iran doc, and Medlib, as well as international databases, including PubMed, Medline, and ISI were searched for published articles associated with evaluation of seroconversion rates after hepatitis-B vaccination in Iranian children. The search was performed in the Persian and/or English language and in under five-year-old children in Iran. The variance of each study was calculated using the binomial distribution formula. The results of studies were combined using random-effects meta-analysis model. Data were analyzed using STATA version 12. Results: In the present research, 11 studies, performed from 2000 to 2017, were investigated. The number of samples in these 11 studies were 3063 children (1592 males and 1471 females). In the studies, the efficacy range of the hepatitis-B vaccine in under five-year-old children in Iran was 89 (95 CI: 86 -93) with high heterogeneity (P value for heterogeneity was 0.001, I-2 = 92.9). Range of efficacy for males and females was 85 (95 CI: 78 to 91) and 88 (95 CI: 83 to 93), respectively. Conclusions: The hepatitis B virus (HBV) vaccination program in Iran seems to be highly effective although some questions, such as the effect of gender on responsiveness to vaccine and heterogeneity of different data, remain unclear

Optimized polar-azimuthal orientations for polarized light illumination of different Superconducting Nanowire Single-Photon Detector designs

The optimal orientations are determined for polarized substrate side illumination of three superconducting nanowire single-photon detector (SNSPD) designs: (1) periodic niobium-nitride (NbN) stripes standing in air with dimensions according to conventional SNSPDs, (2) same NbN patterns below ~quarter-wavelength hydrogensilsesquioxane-filled nano-cavity, (3) analogous NbN patterns in HSQ nano-cavity closed by a thin gold reflector. Numerical computation results have shown that the optical response and near-field distribution vary significantly with polar-angle, fi, and these variations are analogous across all azimuthal-angles, gamma, but are fundamentally different in various device designs. Larger absorptance is available due to p-polarized illumination of NbN patterns in P-structure configuration, while s-polarized illumination results in higher absorptance in S-structure arrangement. As a result of p-polarized illumination a global maximum appears on absorptance of bare NbN pattern at polar angle corresponding to NbN-related ATIR; integration with HSQ nano-cavity results in a global absorptance maximum at polar angle corresponding to TIR at sapphire-air interface; while the highest absorptance is observable at perpendicular incidence on P-structures aligned below gold reflector covered HSQ nano-cavity. S-polarized light illumination results in a global absorptance maximum at TIR on bare NbN patterns; the highest absorptance is available below HSQ nano-cavity at polar angle corresponding to ATIR phenomenon; while the benefit of gold reflector is large and polar angle independent absorptance.Comment: 24 pages, 7 figure

Timing performance of 30-nm-wide superconducting nanowire avalanche photodetectors

We investigated the timing jitter of superconducting nanowire avalanche photodetectors (SNAPs, also referred to as cascade switching superconducting single photon detectors) based on 30-nm-wide nanowires. At bias currents (IB) near the switching current, SNAPs showed sub 35 ps FWHM Gaussian jitter similar to standard 100 nm wide superconducting nanowire single-photon detectors. At lower values of IB, the instrument response function (IRF) of the detectors became wider, more asymmetric, and shifted to longer time delays. We could reproduce the experimentally observed IRF time-shift in simulations based on an electrothermal model, and explain the effect with a simple physical picture

Non-Orthogonal Multiple Access for FSO Backhauling

We consider a free space optical (FSO) backhauling system which consists of two base stations (BSs) and one central unit (CU). We propose to employ non-orthogonal multiple access (NOMA) for FSO backhauling where both BSs transmit at the same time and in the same frequency band to the same photodetector at the CU. We develop a dynamic NOMA scheme which determines the optimal decoding order as a function of the channel state information at the CU and the quality of service requirements of the BSs, such that the outage probabilities of both BSs are jointly minimized. Moreover, we analyze the performance of the proposed NOMA scheme in terms of the outage probability over Gamma-Gamma FSO turbulence channels. We further derive closed-form expressions for the outage probability for the high signal-to-noise ratio regime. Our simulation results confirm the analytical derivations and reveal that the proposed dynamic NOMA scheme significantly outperforms orthogonal transmission and existing NOMA schemes.Comment: This paper has been submitted to IEEE WCNC 201

Statistical Modeling of FSO Fronthaul Channel for Drone-based Networks

We consider a drone-based communication network, where several drones hover above an area and serve as mobile remote radio heads for a large number of mobile users. We assume that the drones employ free space optical (FSO) links for fronthauling of the users' data to a central unit. The main focus of this paper is to quantify the geometric loss of the FSO channel arising from random fluctuation of the position and orientation of the drones. In particular, we derive upper and lower bounds, corresponding approximate expressions, and a closed-form statistical model for the geometric loss. Simulation results validate our derivations and quantify the FSO channel quality as a function of the drone's instability, i.e., the variation of its position and orientation.Comment: This paper has been submitted to ICC 201

A wireless implantable multichannel digital neural recording system for a micromachined sieve electrode

This paper reports the development of an implantable, fully integrated, multichannel peripheral neural recording system, which is powered and controlled using an RF telemetry link, The system allows recording of +/-500 mu V neural signals from axons regenerated through a micromachined silicon sieve electrode, These signals are amplified using on-chip 100 Hz to 3.1 kHz bandlimited amplifiers, multiplexed, and digitized with a low-power (<2 mW), moderate speed (8 mu s/b) current-mode 8-b analog-to-digital converter (ADC), The digitized signal is transmitted to the outside world using a passive RF telemetry link, The circuit is implemented using a bipolar CMOS process, The signal processing CMOS circuitry dissipates only 10 mW of power from a 5-V supply while operating at 2 MHz and consumes 4 x 4 mm(2) of area, The overall circuit including the RF interface circuitry contains over 5000 transistors, dissipates 90 mW of power, and consumes 4 x 6 mm(2) of area