A Joint Design for Multi-band Heterogeneous Networks when Deploying Reconfigurable Intelligent Surface

Wenyu Jiang,Kaizhi Huang,Yajun Chen,Xiaoli Sun,Jie Yang,Kai Zhao 한국통신학회 2022 Journal of communications and networks Vol.24 No.5

Reconfigurable Intelligent Surface (RIS) technique is effective to improve the capacity and coverage of various networks. However, the practical RIS has dissimilar responses to signals in different frequencies due to its structure. Therefore, directly applying existing schemes to multi-band heterogeneous networks leads to beam misalignment and performance degra- dation issues. This paper considers RIS-assisted multi-band heterogeneous networks where base stations (BSs) use different frequencies. We formulate the problem for maximizing the sum rate of all users (SR) in every frequency band, and aim to jointly design BSs precoding vectors and RIS parameters while taking user choices into account. Based on the closed-form relationship of phase shifts between frequencies, an iterative algo- rithm is proposed to solve the challenging non-convex problems. In particular, we use fractional programming to decouple the problem, and solve the subproblems with Quadratic Transform (QT) and Genetic Algorithm (GA). Simulation results show that the proposed scheme can significantly improve SR among all frequency bands, which could instruct the coexistence of mul- tiple communication systems in future heterogeneous networks. What’s more, results also prove that deploying RISs recklessly will result in a degradation of the network.

Semi-solid State Fermentation of Food Waste for Production of Bacillus thuringiensis Biopesticide

Wenyu Zhang,Hui Zou,Lin Jiang,Juejun Yao,Jing Liang,Qunhui Wang 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.6

In this study, Bacillus thuringiensis (Bt) biopesticide was produced through different fermentation processes using food waste with different water contents. The semi-solid state sample with 75% water content presented the highest δ-endotoxin efficiency of 862 μg/mL. δ-endotoxin efficiency increased by 30.2% from that of the solid-state sample (50% water content) and 73.8% from that of the submerged sample (99% water content). Results confirmed that semi-solid state fermentation presents considerable advantages compared with other fermentation types (solid-state and submerged). The timing adjustment of pH and recycling fermentation effectively counteracted the inhibition of pH and product, thereby increasing δ- endotoxin efficiency to 1,648 and 2,478 μg/mL (accumulated value of all four fermentation loops), respectively. A δ- endotoxin slow-release formulation using polylactic acid as the carrier was also developed to effectively promote the stability of Bt biopesticide.

Progressive collapse of steel-framed gravity buildings under parametric fires

Jian Jiang,Wenyu Cai,Guo-Qiang Li,Wei Chen,Jihong Ye 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.4

This paper investigates the progressive collapse behavior of 3D steel-framed gravity buildings under fires with a cooling phase. The effect of fire protections and bracing systems on whether, how, and when a gravity building collapses is studied. It is found that whether a building collapses or not depends on the duration of the heating phase, and it may withstand a “short-hot” fire, but collapses under a mild fire or a “long-cool” fire. The collapse time can be conservatively determined by the time when the temperature of steel columns reaches a critical temperature of 550 °C. It is also found that the application of a higher level of fire protection may prevent the collapse of a building, but may also lead to its collapse in the cooling phase due to the delayed temperature increment in the heated members. The tensile membrane action in a heated slab can be resisted by a tensile ring around its perimeter or by tensile yielding lines extended to the edge of the frame. It is recommended for practical design that hat bracing systems should be arranged on the whole top floor, and a combination of perimeter and internal vertical bracing systems be used to mitigate the fire-induced collapse of gravity buildings. It is also suggested that beam-to-column connections should be designed to resist high tensile forces (up to yielding force) during the cooling phase of a fire.

Investigation of the Probability of a Safe Evacuation to Succeed in Subway Fire Emergencies Based on Bayesian Theory

Jinghong Wang,Wenyu Yan,Han Xu,Youran Zhi,Zhirong Wang,Juncheng Jiang 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.3

Emergency evacuation in subway fires is one of the hot issues in public safety. Based on Bayesian theory, a dynamic evacuation risk analysis model considering both psychological and behavioral responses of evacuees was proposed in this contribution. A subway fire scene was modeled using the Event Tree Analysis (ETA) according to the questionnaire survey at Nanjing Xinjiekou station. In this fire scenario, three control events (the fire alarm, the exhaust system and the evacuation route) were related to fire evacuation control and two control events (active escape and passive escape), which were specifically defined, were related to personnel characteristics. Subsequently, the probability of the final state of each scene was calculated by Monte Carlo simulation. Combined with the statistics of accidents and safe evacuation of subway fire cases from 1976 to 2013, the posterior probability distribution of safety evacuation was obtained after real-time dynamic updating of its precursor probability through Bayesian theory. Results show that the posterior probability of safety evacuation to succeed is around 0.8. This indicates that there is still a probability of 0.2 resulting in injury or fatalities in subway accidents even though most passengers are safely evacuated. It also suggests that utilization of 0.2 as the safety threshold would be an appropriate choice.

Dexmedetomidine promotes the progression of hepatocellular carcinoma through hepatic stellate cell activation

Chen Peng,Luo Xiaojun,Dai Guanqi,Jiang Yuchuan,Luo Yue,Peng Shuang,Wang Hao,Xie Penghui,Qu Chen,Lin Wenyu,Hong Jian,Ning Xue,Li Aimin 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

Dexmedetomidine (DEX) is an anesthetic that is widely used in the clinic, and it has been reported to exhibit paradoxical effects in the progression of multiple solid tumors. In this study, we sought to explore the mechanism by which DEX regulates hepatocellular carcinoma (HCC) progression underlying liver fibrosis. We determined the effects of DEX on tumor progression in an orthotopic HCC mouse model of fibrotic liver. A coculture system and a subcutaneous xenograft model involving coimplantation of mouse hepatoma cells (H22) and primary activated hepatic stellate cells (aHSCs) were used to study the effects of DEX on HCC progression. We found that in the preclinical mouse model of liver fibrosis, DEX treatment significantly shortened median survival time and promoted tumor growth, intrahepatic metastasis and pulmonary metastasis. The DEX receptor (ADRA2A) was mainly expressed in aHSCs but was barely detected in HCC cells. DEX dramatically reinforced HCC malignant behaviors in the presence of aHSCs in both the coculture system and the coimplantation mouse model, but DEX alone exerted no significant effects on the malignancy of HCC. Mechanistically, DEX induced IL-6 secretion from aHSCs and promoted HCC progression via STAT3 activation. Our findings provide evidence that the clinical application of DEX may cause undesirable side effects in HCC patients with liver fibrosis.

CoMP Transmission for Safeguarding Dense Heterogeneous Networks with Imperfect CSI

( Xu Yunjia ),( Huang Kaizhi ),( Hu Xin ),( Zou Yi ),( Chen Yajun ),( Jiang Wenyu ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.1

To ensure reliable and secure communication in heterogeneous cellular network (HCN) with imperfect channel state information (CSI), we proposed a coordinated multipoint (CoMP) transmission scheme based on dual-threshold optimization, in which only base stations (BSs) with good channel conditions are selected for transmission. First, we present a candidate BSs formation policy to increase access efficiency, which provides a candidate region of serving BSs. Then, we design a CoMP networking strategy to select serving BSs from the set of candidate BSs, which degrades the influence of channel estimation errors and guarantees qualities of communication links. Finally, we analyze the performance of the proposed scheme, and present a dual-threshold optimization model to further support the performance. Numerical results are presented to verify our theoretical analysis, which draw a conclusion that the CoMP transmission scheme can ensure reliable and secure communication in dense HCNs with imperfect CSI.

Selection of Potential Virulence Factors Contributing to Streptococcus suis Serotype 2 Penetration into the Blood-Brain Barrier in an In Vitro Co-Culture Model

( Hongtao Liu ),( Seng Zhu ),( Yingying Sun ),( Na Li ),( Jingmin Gu ),( Changjiang Sun ),( Xin Feng ),( Wenyu Han ),( Jianxia Jiang ),( Liancheng Lei ) 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.1

Meningitis caused by Streptococcus suis serotype 2 (S. suis 2) is a great threat to the pig industry and human health. Virulence factors associated with the pathogenesis of meningitis have yet to be clearly defined, even though many potential S. suis 2 virulence factors have been identified. This greatly hinders the progress of S. suis 2 meningitis pathogenesis research. In this study, a co-culture blood-brain barrier (BBB) model was established using primary porcine brain microvascular endothelial cells and astrocytes, and the whole genome library of S. suis 2 was constructed using phage display technology. Finally, a total of 14 potential virulence factors contributing to S. suis 2 adherence to and invasion of the BBB were selected by analyzing the interactions between the phage library and the co-culture model. Twelve of these factors have not been previously reported in meningitis-related research. The data provide valuable insight into the pathogenesis of S. suis 2 meningitis and potential targets for the development of drug therapies.