Joint UL/DL Resource Allocation for UAV-Aided Full-Duplex NOMA Communications

This paper proposes an unmanned aerial vehicle (UAV)-aided full-duplex non-orthogonal multiple access (FD-NOMA) method to improve spectrum efficiency. Here, UAV is utilized to partially relay uplink data and achieve channel differentiation. Successive interference cancellation algorithm is used to eliminate the interference from different directions in FD-NOMA systems. Firstly, a joint optimization problem is formulated for the uplink and downlink resource allocation of transceivers and UAV relay. The receiver determination is performed using an access-priority method. Based on the results of the receiver determination, the initial power of ground users (GUs), UAV, and base station is calculated. According to the minimum sum of the uplink transmission power, the Hungarian algorithm is utilized to pair the users. Secondly, the subchannels are assigned to the paired GUs and the UAV by a message-passing algorithm. Finally, the transmission power of the GUs and the UAV is jointly fine-tuned using the proposed access control methods. Simulation results confirm that the proposed method achieves higher performance than state-of-the-art orthogonal frequency division multiple-access method in terms of spectrum efficiency, energy efficiency, and access ratio of the ground users

A Novel Kunitzin-Like Trypsin Inhibitor Isolated from Defensive Skin Secretion of Odorrana versabilis

Protease inhibitors that were identified from amphibian skin secretions with low molecular weights and potent inhibitory activity were thought to be potential candidates for novel peptide drugs. Here, a novel peptide with trypsin inhibitory activity was found in the skin secretion of the Chinese bamboo leaf odorous frog, Odorrana versabilis. Based on the sequence alignments of sequencing results, the novel peptide (ALKYPFRCKAAFC) was named as Kunitzin-OV. The synthetic replicate of Kunitzin-OV was subjected to a series of functional assays, and it exhibited a trypsin inhibitory activity with a Ki value of 3.042 µM, whereas, when Lys-9 at P1 position was substituted by Phe, trypsin inhibitory activity was undetected and the chymotrypsin inhibitory activity was optimized with a Ki value of 2.874 µM. However, its protease-binding loop was catabolized by trypsin during the trypsin cleavage test. In conclusion, Kunizin-OV is a novel peptide with trypsin inhibitory activity as a member of kunitzins, which is a non-typical Kunitz-like trypsin inhibitor with a highly conserved reactive site (K-A) and quite a short sequence

Capacity of Magnetic-Induction MIMO Communication for Wireless Underground Sensor Networks

In underground sensor networks, electronic magnetic waves undergo severe fading due to the challenging environment. Magnetic-induction (MI) communication is a promising alternative physical layer technique for underground sensor networks. In this paper, we solve the intercoil crosstalk in magnetic-induction multiple-input multiple-output (MI MIMO) communication and investigate the channel capacity for underground MI MIMO wireless communication. Firstly, considering mutual induction between each two coils, we analyze the capacity of magnetic-induction channel. Secondly, the channel model of magnetic-induction multiple-input single-output (MISO) is introduced and a novel coil deployment method is proposed to reduce the crosstalk in MI MISO communication. Finally, the capacity of MI MISO communication and MI MIMO communication is deduced by the proposed coil deployment method. Simulation shows that the channel capacity would increase significantly in high SNR regime for underground MI MIMO communication

The Genus <i>Chrysosporium</i>: A Potential Producer of Natural Products

Chrysosporium, a genus of ascomycete fungi in the family Onygenaceae, has the ability to produce abundant new bioactive natural products, providing a structural foundation in drug development. This review includes the sources, distribution, biological activities and structural characteristics of the compounds isolated from Chrysosporium from 1984 to 2021. The results show that 66% of the compounds isolated from Chrysosporium are new natural products. More than half of the Chrysosporium-isolated compounds are from marine-derived Chrysosporium. The chemical structures of Chrysosporium-derived compounds have different skeletons, which are concentrated in alkaloids, polyketides, and lactones. Eighty percent of the natural products isolated from Chrysosporium have been found to have various biological activities, including cytotoxic, antibacterial, antifungal and enzyme-inhibitory activities. These results demonstrate the potential of Chrysosporium for producing new bioactive secondary metabolites, which can be used as the structural basis for developing new drugs

Energy Efficient Power Allocation for Bidirectional Relaying with Imperfect Channel Estimation

A wireless network scenario of bidirectional relaying with imperfect channel side information (CSI) is considered, in which two source nodes intend to exchange information with the help of one relay. The power allocation problem is investigated to minimize the total transmit power subject to constraints on two source nodes' received signal-to-noise-ratios (SNRs). The best relay that minimizes the total transmit power is selected in a multiple relay network. We also present outage analysis when the proposed power allocation is adopted, and a close-form approximation of outage probability is obtained by shrinking the integral interval. Simulation results show that the total transmit power can be substantially decreased and the outage probability is significantly decreased by the proposed power allocation scheme when two source nodes have different QoS requirement

Research on microstructure and properties of Ti-15Mo-3Al alloy with high oxygen content

In this paper, the near-equilibrium microstructure and properties of Ti-15Mo-3Al-1O alloy treated by solid solution at different temperatures were systematically studied. The microstructure of the alloy was observed and analyzed by optical microscope (OM), scanning electron microscope (SEM) and x-ray diffraction (XRD). The results indicated that the microstructure composed of equiaxial β grains without any precipitate was detected after solution treatment at 1,100 °C/4 h and 1,200 °C/2 h. In addition, the lattice parameters of β phase increased gradually with the increasing of solution temperature. Hardness and room temperature compression test were performed using Vickers hardness tester and universal testing machine. The results showed that the alloy subjected to solution treatment exhibited a high level of hardness value, with the minimum value of 367HV; the alloy subjected to solution treatment at 800 °C/2 h exhibited high compressive yield strength, with the maximum value of nearly 1,650 MPa; the alloy subjected to solution treatment at 1,100 °C/2 h and 1,200 °C/2 h exhibited excellent compressive ductility (The specimens were not crushed, the strain δ  > 50%) with high compressive yield strength (YS > 1,100Mpa)