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Common Correlated Effects Estimation of Unbalanced Panel Data Models with Cross-Sectional Dependence
Qian kun Zhou,Yong hui Zhang 한국계량경제학회 2016 JOURNAL OF ECONOMIC THEORY AND ECONOMETRICS Vol.27 No.4
We consider the estimation and inference of unbalanced panel data models with cross-sectional dependence with a large number of individual units in a relatively short time period. By following the common correlated effects (CCE) approach of Pesaran (2006), we propose a CCE estimator for unbalanced panels (CCE-UB). The asymptotics of the CCE-UB estimator is developed in the paper. Small scale Monte Carlo simulation is conducted to examine the finite sample properties of the proposed estimator.
Qian Kun,Xu Wei,Xia Xiaoyao,Ding Jinhuo 한국유전학회 2022 Genes & Genomics Vol.44 No.12
Background: Methyltransferase-like 3 (METTL3) is an RNA N6-methyladenosine (m6A) methyltransferase, which plays a critical role in micorRNA (miRNAs) processing and maturation, but it is still unclear whether METTL3 regulated miRNAs participates in the regulation of cancer aggressiveness in gastrointestinal stromal tumors (GISTs). Objectives: This study was designed to investigate this issue, and uncover the potential underlying mechanisms. Methods: the expression of METTL3 in GISTs tissues and cell lines were determined by RT-qPCR and Western blot. Cell proliferation and migration were assessed by colony formation, CCK-8 and Transwell. The mRNA expression of all proteins was detected by RT-qPCR, and tumor xenograft study was applied to confirm the effect of METTL3 on GISTs development in vivo. Results: In our study, we showed that METTL3 was significantly upregulated in GISTs tissues and cell lines. Functional experiments demonstrated that overexpression of METTL3 promoted GISTs cell malignant biological behavior and tumor growth in vitro and in vivo, and conversely, silencing of METTL3 had opposite effects and suppressed GISTs progression. Further mechanistical experiments verified that METTL3 promoted the maturation of miR-25-3p in an m6A-dependent manner. Similar to METTL3, miR-25-3p was also validated as an oncogene to promote cancer development in GISTs. Finally, our rescuing experiments hinted that silencing of miR-25-3p abrogated the tumor-initiating effects of METTL3 overexpression on GISTs. Conclusion: Collectively, those results indicated that METTL3 played an oncogenic role in GISTs through positively modulating the miR-25-3p in an m6A-dependent manner, and we firstly discussed how the METTL3/m6A/miR-25-3p axis affected GISTs development.
Energy-Efficient Antenna Selection in Green MIMO Relaying Communication Systems
Kun Qian,Wen-Qin Wang 한국통신학회 2016 Journal of communications and networks Vol.18 No.3
In existing literature on multiple-input multiple-output(MIMO) relaying communication systems, antenna selection is oftenimplemented by maximizing the channel capacity or the outputsingle-to-noise ratio (SNR). In this paper, we propose an energyefficientlow-complexity antenna selection scheme for MIMO relayingcommunication systems. The proposed algorithm is basedon beamforming andmaximizing the Frobenius norm to jointly optimizethe transmit power, number of active antennas, and antennasubsets at the source, relaying and destination. We maximize theenergy efficiency between the link of source to relay and the linkof relay to destination to obtain the maximum energy efficiency ofthe system, subject to the SNR constraint. Compared to existingantenna selection methods forMIMO relaying communication systems,simulation results demonstrate that the proposedmethod cansave more power in term of energy efficiency, while having lowercomputational complexity.
Studies on the Small Body Size Mouse Developed by Mutagen N-Ethyl-N-nitrosourea
Zhang, Qian-Kun,Cho, Kyu-Hyuk,Cho, Jae-Woo,Cha, Dal-Sun,Park, Han-Jin,Yoon, Seok-Joo,Zhang, ShouFa,Song, Chang-Woo Korean Society of ToxicologyKorea Environmental Mu 2008 Toxicological Research Vol. No.
Mutant mouse which show dwarfism has been developed by N-ethyl-N-nitrosourea (ENU) mutagenesis using BALB/c mice. The mutant mouse was inherited as autosomal recessive trait and named Small Body Size (SBS) mouse. The phenotype of SBS mouse was not apparent at birth, but it was possible to distinguish mutant phenotype from normal mice 1 week after birth. In this study, we examined body weight changes and bone mineral density (BMD), and we also carried out genetic linkage analysis to map the causative gene(s) of SBS mouse. Body weight changes were observed from birth to 14 weeks of age in both affected (n = 30) and normal mice (n = 24). BMD was examined in each five SBS and normal mice between 3 and 6 weeks of age, respectively. For the linkage analysis, we produced backcross progeny [(SBS${\times}$C57BL/6J) $F_1{\times}$ SBS] $N_2$ mice (n = 142), and seventy-four microsatellite markers were used for primary linkage analysis. Body weight of affected mice was consistently lower than that of the normal mice, and was 43.7% less than that of normal mice at 3 weeks of age (P < 0.001). As compared with normal mice at 3 and 6 weeks of age, BMD of the SBS mice was significantly low. The results showed 15.5% and 14.1 % lower in total body BMD, 15.3% and 8.7% lower in forearm BMD, and 29.7% and 20.1% lower in femur BMD, respectively. The causative gene was mapped on chromosome 10. The map order and the distance between markers were D10Mit248 - 2.1 cM - D10Mit51 - 4.2 cM - sbs - 0.7 cM - D10Mit283 - 1.4cM - D10Mit106 - 11.2cM - D10Mit170.
Qian Li,Aihong Ji,Huan Shen,Renshu Li,Kun Liu,Xiangming Zheng,Lida Shen,Qingfei Han 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.2
The design of a flapping-wing aircraft is mainly inspired by flying animals: to improve the lift and efficiency of flapping-wing aircraft, their wings, an essential part of the aircraft, mimic the configuration and geometric characteristics of flying animals. Herein, we conducted wing parameter optimization experiments by changing the wing-vein layout, aspect ratio (AR), surface area, and leading-edge-rod flexibility of a flapping-wing aircraft having four wings with double wing clap-and-fling effects. The AR and leading-edge-rod flexibility significantly influenced the lift through the aircraft’s clap-and-fling effects. Analyzing the wing deformation and lift fluctuation revealed that the leading-edge-rod flexibility delayed the trailing-edge separation during clapping, resulting in a large lift at the beginning of peeling. A pentagonal wing of 155-mm wing length, 5.0 AR, a 100-mm breaking point, and an 80-mm wing-vein convergence point at the leading-edge-rod near the wing root was deemed the optimal wing design. This optimal wing design was used to build a 30 g flapping-wing aircraft for an outdoor flight test, which could fly for 6.5 min with a 4.5-g load, thus demonstrating the developed prototype’s potential for autonomous flight.
Kun Rong,Xueping Li,Qian Yang,Ruimin Li,Zaiwang Zhang,Meiling Zou,Huanqiang Zheng,Juanjuan Liu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.120 No.-
Iron nanoparticles supported on corn straw biochar (PE-FeNPs@BC) were used to remove V(V). This materialwas prepared by using Yali pear peel extract-supported iron nanoparticles (PE-FeNPs) as the functionalbody and corn straw biochar (BC) as the support. The synthesis conditions such as Fe/C massratio and synthesis temperature were optimized. The material was characterized by SEM-EDS, FTIR,XRD, and XPS. The results showed that particle agglomeration was reduced, and the dispersion wasimproved after PE-FeNPs were supported on BC. The removal effect was better in the pH range of 2–6,and the removal efficiency was the highest at pH 3.7. At 25 ℃ and pH 3.7, the maximum adsorptioncapacity qm of V(V) was 362.7 mg/g, and 95.1 % of 90 mg/L V(V) was removed. The coexisting NaCl orNaNO3 had a weaker effect on the removal of V(V). The adsorption reactions followed the pseudosecond-order model and Langmuir model, and chemical adsorption was the dominant process. The mainreaction mechanism of PE-FeNPs@BC with V(V) was as follows: adsorbed V5+ was reduced to V4+ by Fe0and Fe2+ and then removed by co-precipitation in the forms of xFe2O3yV2O5zH2O and VO2H2O. Thisstudy promotes the reuse of waste pear peel and can provide an environmentally friendly method forremoving V(V) pollution.
Kun Gao,Xiang Yuan Deng,Meng Ke Shang,Heying Qian,Xijie Guo 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.3
The cDNA of a biphenyl hydrolase-like (BPHL) protein from Bombyx mori was cloned via rapid amplification of cDNA ends and submitted to GenBank under accession number JN020647. The full-length BmBPHL cDNA was 1161 bp, with four exons and three introns. It consisted of a 208 bp 5′-terminal untranslated region (UTR) and a 191 bp 3′-UTR with three polyadenylation signal sequences AATAAA and a poly(A) tail. The BmBPHL cDNA encodes a 253–amino acid polypeptide with a theoretical isoelectric point of 8.67 and a predicted molecular weight of 28.9 kDa. The deduced amino acid sequence of BmBPHL contained an abhydrolase_6 domain and the Gly-X-Ser-X-Gly motif that is characteristic of serine hydrolases. Sequence comparison showed that BmBPHL is 51% identical to Tribolium castaneum BPHL and 50% identical to Nasonia vitripennis BPHL. Phylogenetic analysis revealed that BmBPHL is grouped with insect BPHL proteins, separating from vertebrate BPHLs. The BmBPHL mRNA transcripts were mainly detected in hemolymph and fat body using fluorescent quantitative real-time PCR. In addition, infectionwith B. mori cytoplasmic polyhedrosis virus (BmCPV) upregulated the relative BmBPHL expression in the hemolymph and midgut. Therefore, BmBPHL may have an important function in the response of silkworms to BmCPV infection.