The expansion of thymopoiesis in neonatal mice is dependent on expression of high mobility group a 2 protein (Hmga2).

Cell number in the mouse thymus increases steadily during the first two weeks after birth. It then plateaus and begins to decline by seven weeks after birth. The factors governing these dramatic changes in cell production are not well understood. The data herein correlate levels of High mobility group A 2 protein (Hmga2) expression with these temporal changes in thymopoiesis. Hmga2 is expressed at high levels in murine fetal and neonatal early T cell progenitors (ETP), which are the most immature intrathymic precursors, and becomes almost undetectable in these progenitors after 5 weeks of age. Hmga2 expression is critical for the initial, exponential expansion of thymopoiesis, as Hmga2 deficient mice have a deficit of ETPs within days after birth, and total thymocyte number is repressed compared to wild type littermates. Finally, our data raise the possibility that similar events occur in humans, because Hmga2 expression is high in human fetal thymic progenitors and falls in these cells during early infancy

Distribution of multiband THz wireless signals over fiber

Terahertz wireless communication is receiving great interest from researchers and industries, thanks to the new spectral windows between 0.1 and 1 THz offering opportunities for ultra-high-data-rate wireless transmission. Wavelength division multiplexing for wireless-over-fiber is foreseen as an enabling technique to support connection between base stations and a central station. This paper reviews architectures for photonic distribution and generation of multiband signals for sub- THz wireless communications, giving rates up to 100 Gb/s (20 Gb/s per band) using the full spectrum between 220 GHz and 280 GHz for downlink wireless transmission, and 10 Gb/s for uplink using on-off keying

Multi-service Digital Radio over Fibre System with Millimetre Wave Bridging

© 2018 IEEE. This paper demonstrates a novel digital radio over fibre (DRoF) architecture that is able to transport multiple compressed digitised RF services using both optical fibre and wireless millimetre wave (mmW) links. This solution has advantages as a cost effective indoor wireless infrastructure where flexible transmission schemes are required. Experimental results indicate wide RF dynamic range for two LTE services transmitted simultaneously, showing its capability for creating a neutral-host radio access network (RAN) with good spectral efficiency and cost effectiveness

Integrated Photonics for Wireless and Satellite Applications

The concept of using Photonic Integrated Circuits for generation of tunable mm-wave signals for wireless and satellite communication application is presented. The paper outlines the requirements for frequency stabilization and power consumption of semiconductor lasers when implemented in terrestrial wireless and satellite communication applications

Spectrally-efficient high-speed wireless bridge operating at 250 GHz

A photonic wireless bridge operating at 250 GHz is presented. Using a pilot tone-assisted phase noise compensation technique, a data rate of 40 Gbit/s is achieved using 16-quadrature amplitude modulation. Furthermore, the wireless bridge is also demonstrated in a wavelength division multiplexing scenario

Integrated Wireless-Optical Backhaul and Fronthaul Provision Through Multicore Fiber

In this paper we propose multicore fiber (MCF) as the medium to transport the different signals associated with various wireless applications (ranging from access to fronthauling and backhauling) from the baseband unit (BBU) to the cell-site. Using 1 km of a 7-core MCF, we simultaneously transmit fronthaul and backhaul signals from the BBU to the cell site, where they are converted to carrier frequencies in the mm-wave and sub-THz band, respectively. The backhaul is evaluated with a 12.5 GBd 16-quadrature amplitude modulation (QAM) signal, whereas the fronthaul is evaluated with a 7 Gbit/s on-off keying (OOK) signal carrying 14 LTE-compatible channels. The fronthaul signal is generated with a novel compression technique that achieves an efficiency 3-times higher than the one obtained with the common public radio interface (CPRI) protocol. Optical heterodyining is implemented at the cell site for optical-to-RF conversion. The local oscillator (LO) signal required for optical heterodyning is transmitted in a dedicated core, reducing the system complexity and enabling its straight-forward reuse for uplink (UL) transmission. The experimental demonstration includes the simultaneous full-duplex transmission of both the fronthaul and backhaul signals, using 6 cores of the MCF at the same time and achieving a gross data rate of 57 Gbit/s

Novel compressed digital radio fronthaul over photonically-generated THz wireless bridge

Compressed DRoF-based fronthaul links enable cost-effective last-mile wireless coverage. This paper demonstrates a novel system which carries 12 LTE services over both optical fibre and photonically-generated THz wireless links with over 40 dB dynamic range.</jats:p

Fully monolithic photonic integrated circuits for microwave and millimeter wave signal generation

We present two different photonic integrated circuits aimed to generate electrical signals within the microwave and millimeter wave range with two different techniques. The first approach uses the heterodyne technique, implementing a monolithic dual wavelength source by integrating on a single chip two distributed feedback (DFB) lasers together with the high speed photodiode. The second approach, using mode locked lasers, describes a novel device structure based on multimode interference reflectors (MIR)