Likelihood-based tests on moderate-high-dimensional mean vectors with unequal covariance matrices

Dandan Jiang 한국통계학회 2017 Journal of the Korean Statistical Society Vol.46 No.3

This paper considers linear hypotheses of a set of high-dimensional mean vectors with unequal covariance matrices. To test the hypothesis H0 : qi =1 βiμi = μ0, we use the CLT for the linear spectral statistics of a high-dimensional F-matrix in Zheng (2012) to establish a test statistic based on the likelihood ratio test statistic that is applicable to high-dimensional non-Gaussian variables in a wide range. Furthermore, the results of a simulation are provided to compare the proposed test with other high-dimensional tests. As shown by the simulation results, the empirical size of our proposed test is closer to a significance level, whereas our empirical powers dominate those of the other tests due to the likelihood-based statistic.

An S-scheme photocatalyst constructed by modifying Ni-doped Sn3O4 micro-flowers on g-C3N4 nanosheets for enhanced visible-light-driven hydrogen evolution

Dandan Wang,Zhaoxin Lin,Chun Miao,Wei Jiang,Hongji Li,Chunbo Liu,Guangbo Che 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-

Carbon nitrides (g-C3N4) is considered to be the prospective semiconductor photocatalyst for photocatalytic H2 evolution. Nevertheless, it suffers from low charge transfer efficiency and fewer metal active sites. Thereby, Ni-Sn3O4/g-C3N4 photocatalysts were constructed by anchoring Ni-doped Sn3O4 micro-flowers on g-C3N4 via a feasible and straightforward solvothermal treatment. The prepared Ni-Sn3O4/g-C3N4 S-scheme heterojunction could improve the transfer and separation efficiency of photo-generated electron-hole pairs by facilitating the electrons transfer from Ni-Sn3O4 to g-C3N4. Moreover, the photocatalytic H2 production performance was ameliorated due to the established internal electric field and the energy band bending in Ni-Sn3O4/g-C3N4 S-scheme heterojunction. Meanwhile, the doping Ni in Sn3O4 exposed more active sites in Ni-Sn3O4/g-C3N4 heterojunction for producing H2. As a result, Ni-Sn3O4/g-C3N4-5 photocatalyst exhibited outstanding H2 yields of 1961 µmol h−1 g−1 under visible light irradiation in comparison with pure Ni-Sn3O4 (12 µmol h−1 g−1) and bared g-C3N4 (1391 µmol h−1 g−1). Furthermore, the S-scheme mechanism in Ni-Sn3O4/g-C3N4 heterojunction for producing H2 by oxidizing H2O was proposed. This study provides helpful guide for developing efficient g-C3N4-based photocatalytic systems.

Concurrent classic driver oncogenes mutation with ROS1 rearrangement predicts superior clinical outcome in NSCLC patients

Li Dandan,Jiang Hua,Jin Faguang,Pan Lei,Xie Yonghong,Zhang Liang,Li Chunmei 한국유전학회 2023 Genes & Genomics Vol.45 No.1

Background There is high mortality rate and poor prognosis in lung cancer, especially non-small-cell lung cancer (NSCLC). Recent study showed that concurrent classic driver oncogene mutation with ROS1 rearrangement was found in NSCLC patients. However, whether this would affect the development and prognosis of NSCLC is still unclear. Objective To explore the clinical characteristics and prognosis of NSCLC patients harboring concurrent classic driver oncogene mutation with ROS1 rearrangement. Methods A retrospective study was conducted on 220 patients diagnosed with NSCLC. All samples were screened for EGFR and KRAS using amplification-refractory mutation system assay, and for ALK, ROS1 using RT-PCR. The clinical characteristics and clinical outcomes of concurrent gene alterations with ROS1 rearrangement were analyzed. Results In 220 patients, 12 (5.45%) were ROS1 rearrangement, who tend to be younger, non-smokers. The mutation rates of EGFR, KRAS, ALK and ROS1 in NSCLC were 28.64%, 1.82%, 3.64% and 5.45%, respectively. ROS1 rearrangement was identified to co-occur in 5 (2.27%) NSCLC patients. ROS1/EGFR co-alterations were found in 3.17% of NSCLC patients, 16.67% of ROS1-positive NSCLC patients. Concomitant ROS1/ALK rearrangement constituted 37.50% in ALK-positive patients, and 25.00% in ROS1-positive patients. SDC4-ROS1 was the most common fusion partner in concurrent ROS1 rearrangement patients. The median overall survival of NSCLC with concurrent ROS1 rearrangement group and single ROS1 rearrangement group were 25 months and 14 months. Conclusion Concurrent driver oncogenes mutation with ROS1 rearrangement defines a unique subgroup of NSCLC. Patients with concomitant ROS1 rearrangement might have a better prognosis.

Treatment of penicillin with supercritical water oxidation: Experimental study of combined ReaxFF molecular dynamics

Tengzhou Ma,Tingting Hu,Dandan Jiang,Jinli Zhang,Wei Li,You Han,Banu Örmeci 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.4

Supercritical water oxidation (SCWO) of penicillin (PCN) was investigated under different operating conditions. The chemical oxygen demand (COD) removal rate could reach 99.4% at 400 oC, 24MPa, 1min and oxidation coefficient (OC) of 2. Experimental results showed that COD removal had no significant dependence on temperature and pressure variations. By contrast, COD removal could be significantly promoted with OC increasing from 0 to 2.0, but the effect was negligible as the OC further increased; similarly, longer residence time than a definite value seemed to contribute little to COD removal. Initial and deeper degradation pathways of penicillin were proposed based on the reactive force field (ReaxFF) molecular dynamics (MD) simulations. By tracing the evolution of intermediates, the migration routes of S and N during the SCWO process were obtained with H2S and NO2 produced as the corresponding products. Simulation results showed that SCW and oxidant not only accelerated the degradation by producing highly reactive radicals or molecules, but also participated in reactions by serving as H and O sources. Moreover, catalysis of water clusters in C-heteroatom bond cleavage was also observed.

SYNTHESIS AND ORGANIZATION OF PLATINUM NANOPARTICLES AND NANOSHELLS ON A NATIVE VIRUS BIOSCAFFOLD

LI HOU,FAMING GAO,DANDAN TONG,YANG JIANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.6

A wild type virion, bacteriophage T4, was used as an organic template for the controlled synthesisand organization of Pt nanoparticles and nanoshells on its capsid. A long incubation of T4 virionswith the metalchloride solution is necessary to the speci¯c binding of the external surface of T4capsid with Pt IV by means of interactions between Pt IV and the chemical functionality foundinherently on the surface of the proteinaceous viral capsid. After chemical reduction with dime-thylaminoborane (DMAB), the highly dispersive Pt nanoparticles with a uniform size of 3 – 4 nmwere synthesized and covered the whole viral capsid. The packing density of Pt nanoparticles wasenhanced by increasing the incubation cycles of the virions in metal salt solution. Moreover,Pt@T4 shell/core structures could be achieved by increasing the amount of metal ions aroundvirons. UV/vis spectroscopy was used to follow the course of the reaction, and the formationmechanism was discussed. Both the small Pt nanoparticles and Pt@T4 shell/core structures showhigh electrocatalytic activity in electrochemical measurement, and therefore are expected to havepotential applications in electrocatalysis.

CBX7 Rejuvenates Late Passage Dental Pulp Stem Cells by Maintaining Stemness and Pro-angiogenic Ability

Wu Yu,Li Bing,Yu Dandan,Zhou Zhixuan,Shen Ming,Jiang Fei 한국조직공학과 재생의학회 2023 조직공학과 재생의학 Vol.20 No.3

BACKGROUND: Ever-growing tissue regeneration causes pressing need for large population of stem cells. However, extensive cell expansion eventually leads to impaired regenerative potentials. In this study, chromobox protein homolog 7 (CBX7) was overexpressed to rejuvenate late passage dental pulp stem cells (DPSCs-P9). METHODS: The recruitment of copper ions (Cu2?)-activated hypoxia-inducible factor-1a (HIF-1a) to the CBX7 gene promoter was confirmed by chromatin immunoprecipitation assay. Functions subsequent to Cu2?-induced or recombinant overexpression of CBX7 on proliferation, multipotency, odontoblastic differentiation and angiogenesis were investigated in vitro, while murine subcutaneous transplantation model was used to further detect the effects of Cu2?-induced CBX7 overexpression in vivo. RESULTS: Our data displayed that CBX7 overexpression maintain proliferation and multipotency of DPSCs-P9 almost as strong as those of DPSCs-P3. Both gene level of odontoblast-lineage markers and calcium precipitation were nearly the same between CBX7 overexpressed DPSCs-P9 and normal DPSCs-P3. Moreover, we also found upregulated expression of vascular endothelial growth factor in DPSCs-P9 with CBX7 overexpression, which increased the number of capillary-like structures and migrating co-cultured human umbilical vein endothelial cells as well. These findings indicate CBX7 as an effective factor to rejuvenate late passage stem cells insusceptible to cell expansion. Cu2? has been proved to achieve CBX7 overexpression in DPSCs through the initiation of HIF-1a-CBX7 cascade. Under Cu2? stimulation since P3, DPSCs-P9 exhibited ameliorated regenerative potential both in vitro and in vivo. CONCLUSION: Long-term stimulation of Cu2? to overexpress CBX7 could be a new strategy to manufacture large population of self-renewing stem cells.

Radon-induced demethylation of Cdk2 CpG island in the rat lung

Cheng Wu,Qiu Chen,Jian Tong,Xin Xie,Fengmei Cui,Yang Jiao,Dandan Qi,Jihua Nie,Tom K. Hei,Qisheng Jiang 한국유전학회 2014 Genes & Genomics Vol.36 No.6

Radon exposure has been linked to lung carcinogenesisin both human and animal studies. The identificationof sequential changes in DNA methylation duringtumour progression and the elucidation of their interplaywith genetic changes will broaden our molecular understandingof this disease. Rats were exposed to 120 or 400working level months (WLM) of radon, lung pathologicalchanges were examined by haematoxylin and eosin staining,lung single cell suspension cell cycles were detected byflow cytometry, lung cell cycle regulated gene (Cdkn2a,P53, Cdk4/2, Mdm4/2 and Rb1 genes) expression wasquantified by real-time PCR and methylation of CpG islandsin the promoters of cell cycle-regulated genes were detectedby bisulfite sequencing PCR. The alveolar walls of rat lungsafter exposured to radon exhibited papillae and the lungbronchial epithelial cells stained positively for proliferatingcell nuclear antigen. The bronchial epithelial cells displayedsome hyperplasia after challenged by 400 WLM of radon. Moreover, G1 arrest decreased; Rb1, Mdm2/4, and Cdk2/4expression decreased and Cdk2 was demethylated at thesecond and sixth CpG loci from base pairs 3092704 to3092953 of chromosome 7. Cdk2 demethylation may beapplicable as a biomarker of early lung damage that wasinduced by radon and other environmental carcinogens.

Characteristics of the gut microbiota colonization, inflammatory profile, and plasma metabolome in intrauterine growth restricted piglets during the first 12 hours after birth

Shimeng Huang,Na Li,Cong Liu,Tiantian Li,Wei Wang,Lili Jiang,Zhen Li,Dandan Han,Shiyu Tao,Junjun Wang 한국미생물학회 2019 The journal of microbiology Vol.57 No.9

Intrauterine growth restriction (IUGR) predisposes newborns to inflammatory and metabolic disturbance. Disequilibrium of gut microbiota in early life has been implicated in the incidence of inflammation and metabolic diseases in adulthood. This study aimed to investigate the difference in gut microbiota colonization, cytokines and plasma metabolome between IUGR and normal birth weight (NBW) piglets in early life. At birth, reduced (P < 0.05) body, jejunum, and ileum weights, as well as decreased (P < 0.05) small intestinal villi and increased (P < 0.05) ileal crypt depth were observed in IUGR piglets compared with their NBW counterparts. Imbalanced inflammatory and plasma metabolome profile was observed in IUGR piglets. Furthermore, altered metabolites were mainly involved in fatty acid metabolism and inflammatory response. At 12 h after birth and after suckling colostrum, reduced (P < 0.05) postnatal growth and the small intestinal maturation retardation (P < 0.05) continued in IUGR piglets in comparison with those in NBW littermates. Besides, the gut microbiota structure was significantly altered by IUGR. Importantly, the disruption of the inflammatory profile and metabolic status mainly involved the pro-inflammatory cytokines (IL-1β and IFN-γ) and amino acid metabolism. Moreover, spearman correlation analysis showed that the increased abundance of Escherichia-Shigella and decreased abundance of Clostridium_sensu_stricto_1 in IUGR piglets was closely associated with the alterations of slaughter weight, intestinal morphology, inflammatory cytokines, and plasma metabolites. Collectively, IUGR significantly impairs small intestine structure, modifies gut microbiota colonization, and disturbs inflammatory and metabolic profiles during the first 12 h after birth. The unbalanced gut microbiota mediated by IUGR contributes to the development of inflammation and metabolic diseases.