Performance Analysis of Discrete-Phase-Shifter IRS-aided Amplify-and-Forward Relay Network

As a new technology to reconfigure wireless communication environment by signal reflection controlled by software, intelligent reflecting surface (IRS) has attracted lots of attention in recent years. Compared with conventional relay system, the relay system aided by IRS can effectively reduce the cost and energy consumption, and significantly enhance the system performance. However, the phase quantization error generated by IRS with discrete phase shifter may degrade the receiving performance of the receiver. To analyze the performance loss caused by IRS phase quantization error, based on the law of large numbers and Rayleigh distribution, the closed-form expressions for the signal-to-noise ratio (SNR) performance loss and achievable rate of the IRS-aided amplify-and-forward (AF) relay network, which are related to the number of phase shifter quantization bits, are derived under the line-of-sight (LoS) channels and Rayleigh channels, respectively. Moreover, their approximate performance loss closed-form expressions are also derived based on the Taylor series expansion. Simulation results show that the performance losses of SNR and achievable rate decrease with the number of quantization bits increases gradually. When the number of quantization bits is larger than or equal to 3, the SNR performance loss of the system is smaller than 0.23dB, and the achievable rate loss is less than 0.04bits/s/Hz, regardless of the LoS channels or Rayleigh channels

Protein kinase CK2α is overexpressed in colorectal cancer and modulates cell proliferation and invasion via regulating EMT-related genes

<p>Abstract</p> <p>Background</p> <p>Protein kinase CK2 is a highly conserved, ubiquitous protein serine/threonine kinase that phosphorylates many substrates and has a global role in numerous biological and pathological processes. Overexpression of the protein kinase CK2α subunit (CK2α) has been associated with the malignant transformation of several tissues, with not nearly as much focus on the role of CK2α in colorectal cancer (CRC). The aims of this study are to investigate the function and regulatory mechanism of CK2α in CRC development.</p> <p>Methods</p> <p>Expression levels of CK2α were analyzed in 144 patients (104 with CRC and 40 with colorectal adenoma) by immunohistochemistry. Proliferation, senescence, motility and invasion assays as well as immunofluorescence staining and western blots were performed to assess the effect of CK2α in CRC.</p> <p>Results</p> <p>The immunohistochemical expression of nuclear CK2α was stronger in tumor tissues than in adenomas and normal colorectal tissues. Suppression of CK2α by small-interfering RNA or the CK2α activity inhibitor emodin inhibited proliferation of CRC cells, caused G0/G1 phase arrest, induced cell senescence, elevated the expression of p53/p21 and decreased the expression of C-myc. We also found that knockdown of CK2α suppressed cell motility and invasion. Significantly, CK2α inhibition resulted in β-catenin transactivation, decreased the expression levels of vimentin and the transcription factors snail1 and smad2/3, and increased the expression of E-cadherin, suggesting that CK2α regulates the epithelial-mesenchymal transition (EMT) process in cancer cells.</p> <p>Conclusions</p> <p>Our results indicate that CK2α plays an essential role in the development of CRC, and inhibition of CK2α may serve as a promising therapeutic strategy for human CRC.</p

Constructing quantum dots@flake g-C3N4 isotype heterojunctions for enhanced visible-light-driven NADH regeneration and enzymatic hydrogenation

The authors thank the financial support from National Natural Science Funds of China (21406163, 91534126, 21621004), Tianjin Research Program of Application Foundation and Advanced Technology (15JCQNJC10000), Open Funding Project of the National Key Laboratory of Biochemical Engineering (2015KF-03), and the Program of Introducing Talents of Discipline to Universities (B06006). X.W. also acknowledges financial support from The Carnegie Trust for the Universities of Scotland (70265) and The Royal Society (RG150001 and IE150611).Peer reviewedPostprin

Observation of two PT transitions in an electric circuit with balanced gain and loss

We investigate -symmetry breaking transitions in a dimer comprising two LC oscillators, one with loss and the second with gain. The electric energy of this four-mode model oscillates between the two LC circuits, and between capacitive and inductive energy within each LC circuit. Its dynamics are described by a non-Hermitian, -symmetric Hamiltonian with three different phases separated by two exceptional points. We systematically measure the eigenfrequencies of energy dynamics across the three regions as a function of gain-loss strength. In addition to observe the well-studied transition for oscillations across the two LC circuits, at higher gain-loss strength, transition within each LC circuit is also observed. With their extraordinary tuning ability, -symmetric electronics are ideally suited for classical simulations of non-Hermitian systems

Coordination between electron transfer and molecule diffusion through a bioinspired amorphous titania nanoshell for photocatalytic nicotinamide cofactor regeneration

In-depth understanding and rational manipulation of the electron transfer process and molecule diffusion process are critical to promote the overall photocatalytic efficiency. In our study, core@shell photocatalysts that embody graphitic carbon nitride (GCN) core and amorphous titania (a-TiO 2) nanoshell are prepared to elucidate and coordinate the electron transfer and molecule diffusion for the regeneration of nicotinamide adenine dinucleotide (NADH) with [Cp*Rh(bpy)H 2O] 2+ as the redox mediator. The GCN core absorbs visible light to generate electron-hole pairs, whereas the a-TiO 2 nanoshell facilitates the transfer of photogenerated electrons from GCN to the a-TiO 2 surface for NADH regeneration, which also enables the diffusion of electron donor molecules (triethanolamine, TEOA) from the a-TiO 2 surface to GCN for consuming the holes left on GCN. The transfer of photogenerated electrons and the diffusion of electron donor molecules are coordinated by finely tuning the thickness of the a-TiO 2 nanoshell. Under the optimized nanoshell thickness of â¼2.1 nm, the GCN@a-TiO 2 photocatalyst exhibits the highest NADH regeneration yield of 82.1% after a 10 min reaction under LED light (405 nm), over 200% higher than that of the GCN photocatalyst. Combined with the highly controllable and mild features of the bioinspired mineralization method, our study may offer a facile and generic strategy to design high performance photocatalysts through rational coordination of different substances/species transport processes

Clinicopathological characteristics of gastric cancer patients with dermatomyositis and analysis of perioperative management: a case series study

BackgroundThis study aimed to investigate the clinical characteristics of gastric cancer (GC) patients with dermatomyositis (DM) and summarize the perioperative outcomes.MethodsThe clinical and pathological data of five patients diagnosed with co-occurring DM and GC (DM-GC group) were retrospectively analyzed, who were admitted to the Department of Gastrointestinal Surgery at Ren ji Hospital, Shanghai Jiao Tong University, between January 2012 and April 2023. Their data were compared with 618 GC patients (GC-1 group) from September 2016 to August 2017 and 35 GC patients who were meticulously screened from 14,580 GC cases from January 2012 and April 2023. The matching criteria included identical gender, age, tumor location, TNM stage, and surgical procedure (7 GC patients were matched for each DM-GC patient).ResultsAnalysis indicated that the DM-GC group comprised four female and one male patient. The female proportion was significantly higher (P = 0.032) than that of GC-1 group. In DM-GC group, four DM patients were diagnosed as GC within 12 months. One DM patients was diagnosed as GC within 15 months. Among them, four patients presented with varying degrees of skin rashes, muscle weakness while one patient had elevated CK levels as the typical symptom. Similarly, the preoperative tumor markers (CA-199 and CA-125) in the DM-GC group were significantly higher than normal levels (CA-199: 100 vs. 28.6%, P = 0.002; CA-125: 40 vs. 2.9%, P = 0.003) compared to GC-2 group. Moreover, postoperative complication incidence and the length of hospital stay were significantly higher in the DM-GC than GC-2 group [complication rate: 40 vs. 8.6%, P = 0.047; hospital stay: 15 days (range: 9–28) vs. 9 days (range: 8–10), P = 0.021].ConclusionGC Patients with dermatomyositis are more prone to experience postoperative complications and longer hospital stay

Cavitation Characteristics on Flow with Multi Cavitation Sources

The cavitation characteristics were analyzed in this paper for the flood relief mid-outlets of Baise Multipurpose dam project, on the basis of depressurized model test of 1:50 in a specially designed vacuum chamber. The results of test demonstrate that there exists relatively distinct cavitation cloud at the gate slots and outlet diffusion zones of spillways. Mutual disturbance of cavitation noise from two sources leads to the relationship curve becoming concave downward and the frequency spectrum sound pressure level decreasing correspondingly when h is close to hm (h/hm = 1). Its pattern is not in conformity with the general law. The discovery may have certain supplementation for the standard of judging the cavitation emergence

Physics-Based Table-Top Mixed Reality Games

Mixed reality applications use techniques from computer vision, augmented reality and virtual reality to allow real and virtual objects interact physically together on a user’s computer screen. This paper will describe two mixed reality applications which allow the user to play games that appear to take place on top of their physical desk. The games described are a desktop racing game and a desktop based game of ten pin bowling. In the desktop racing game virtual cars, controlled by the user, interact with both virtual objects (such as trees, walls and lampposts) and real ones (such as ramps and blocks). In the bowling game the player throws a real ball at a set of virtual bowling pins which react realistically as the ball appears to hit them. These initial games are being used as a springboard to investigate the core competencies required to make mixed reality games

Design and Gait Optimization of Quadruped Robot Based on Energy Conservation

Stability and energy consumption are important performance indicators for quadruped robots. In this paper, a simple quadruped robot with high dynamic performance and a distributed control system based on CPG are designed. Moreover, the ADAMS-MATLAB joint simulation platform is established to study the influence of gait parameters on gait stability and energy consumption. The optimal step length is obtained through theoretical calculation, and a gait optimization strategy is proposed to improve the stability of the quadruped robot and reduce the energy consumption. Finally, a single-leg experiment platform was built to realize the robot\u27s specific gait under optimized conditions and test the accuracy and robustness of the control system. The results of experiment and simulation show the feasibility of the design and gait optimization methods for the quadruped robot and achieve energy consumption and high dynamic performance