All-fiber loading sensor based on a hybrid 45° and 81° tilted fiber grating structure

We experimentally demonstrate an all-fiber loading sensor system based on a 45° and an 81° tilted fiber grating (TFG). We have fabricated two TFGs adjacent to each other in a single fiber to form a hybrid structure. When the transverse load applied to the 81° TFG, the light coupling to the two orthogonally polarized modes will interchange the power according to the load applied to the fiber, which provides a solution to measure the load. For real applications, we further investigated the interrogation of this all-fiber loading sensor system using a low-cost and compact-size single wavelength source and a power meter. The experimental results have clearly shown that a low-cost high-sensitivity loading sensor system can be developed based on the proposed TFG configuration

Physical Layer Security of Cooperative NOMA for IoT Networks under I/Q Imbalance

In this paper, we investigate the reliability and security of cooperative dual-hop non-orthogonal multiple access (NOMA) for internet-of-thing (IoT) networks, in which the transceivers consider a detrimental factor of in-phase and quadrature-phase imbalance (IQI). The communication between the source and destination is accomplished through a decode-and-forward (DF) relay in the presence of an eavesdropper. In order to characterize the performance of the considered system, exact analytical expressions for the outage probability (OP) and intercept probability (IP) are derived in closed-form. Furthermore, to better understanding the performance of the considered system, we further derive the asymptotic expressions of OP in the high signal-to-noise ratio (SNR) regime and IP at the high main eavesdropping ratio (MER) region. A large number of analysis and Monte Carlo simulation results show that the existence of IQI usually increases the corresponding OP and reduces the IP, which means that reduces the reliability of the system and improves the security. In addition, the provided results provide useful insights into the trade-off between reliability and security of secure cooperative communication systems

All-fiber loading sensor based on 45° and 81° tilted fiber gratings

Cardiovascular health of the human population is a major concern for medical clinicians, with cardiovascular diseases responsible for 48% of all deaths worldwide, according to the World Health Organisation. Therefore the development of new practicable and economical diagnostic tools to scrutinise the cardiovascular health of humans is a major driver for clinicians. We offer a new technique to obtain seismocardiographic signals covering both ballistocardiography (below 20Hz) and audible heart sounds (20Hz upwards). The detection scheme is based upon an array of curvature/displacement sensors using fibre optic long period gratings interrogated using a variation of the derivative spectroscopy interrogation technique

Single polarization, dual wavelength fiber laser based on a 3-stage all fiber lyot filter

We have demonstrated a switchable dual wavelength fiber ring laser with a high degree of polarization output by using an intracavity 3-stage all fiber Lyot filter. The filter is formed by concatenating four 45° tilted fiber gratings separated by polarization maintaining fibers with a length ratio of 1:2:4 (20, 40, and 80 cm), giving a compact integrated configuration with reduced bandwidth. Switchable dual wavelength or single wavelength output at 1533.5 and 1563.3 nm has been achieved. The output lasing is considerably stable owing to the in-phase mode-selecting function of the multistage Lyot filter, and has a very high degree of polarization higher than 99.9%

Achievable Degrees of Freedom for the Two-Cell Two-Hop MIMO Interference Channel With Half-Duplex Relays

We consider the two-cell two-hop multiple-input–multiple-output interference channel with half-duplex relays, where each source group having $M$ single antenna users communicates with the corresponding destination with $M$ antennas via two relays, each having $M$ antennas. For such a channel, by exploiting three time slots, the previously known achievable degrees of freedom (DoF) is $2M/3$ regardless of whether the half-duplex relays have global channel state information (CSI) for the first hop. In this paper, we show that using $n\geq 3$ time slots, the achievable DoF is $(n-1)M/n$ , which is higher than the previous result of $2M/3$ DoF for the case of $n\geq 4$ . The achievability is shown by a new relaying protocol, which combines the alternate transmission strategy with an interference cancellation technique. A major implication of the derived result is that a normalized DoF of one can be achieved asymptotically without requiring global CSI at the source and relay nodes

GFI1 downregulation promotes inflammation-linked metastasis of colorectal cancer.

Inflammation is frequently associated with initiation, progression, and metastasis of colorectal cancer (CRC). Here, we unveil a CRC-specific metastatic programme that is triggered via the transcriptional repressor, GFI1. Using data from a large cohort of clinical samples including inflammatory bowel disease and CRC, and a cellular model of CRC progression mediated by cross-talk between the cancer cell and the inflammatory microenvironment, we identified GFI1 as a gating regulator responsible for a constitutively activated signalling circuit that renders CRC cells competent for metastatic spread. Further analysis of mouse models with metastatic CRC and human clinical specimens reinforced the influence of GFI1 downregulation in promoting CRC metastatic spread. The novel role of GFI1 is uncovered for the first time in a human solid tumour such as CRC. Our results imply that GFI1 is a potential therapeutic target for interfering with inflammation-induced CRC progression and spread

The first fossil brown lacewing from the Miocene of the Tibetan Plateau (Neuroptera, Hemerobiidae)

A new species of Hemerobiidae, Wesmaelius makarkini Yang, Pang & Ren, sp. n. is described from the Lower Miocene, Garang Formation of Zeku County, Qinghai Province (northeastern Tibetan Plateau), China. The species is assigned to the widely distributed extant genus Wesmaelius Krüger (Hemerobiinae). The species represents the first named fossil of this family from China, which sheds light on the historical distribution of Wesmaelius and early divergences within Hemerobiinae