DFT and TD-DFT study on structure and properties of organic dye sensitizer TA-St-CA

Cai-Rong Zhang,Zi-Jiang Liu,Yu-Hong Chen,Hong-Shan Chen,You-Zhi Wu,WangJun Feng,Dao-Bin Wang 한국물리학회 2010 Current Applied Physics Vol.10 No.1

The geometry, electronic structure, polarizability and hyperpolarizability of organic dye sensitizer TA-St-CA, which contains a π-conjugated oligo-phenylenevinylene unit with an electron donor.acceptor moiety, was studied using density functional theory (DFT), and the electronic absorption spectrum was investigated via time-dependent DFT (TD-DFT) with several hybrid functionals. The calculated geometry indicates that the strong conjugated effects are formed in the dye. The TD-DFT results show that the hybrid functional PBE1PBE and MPW1PW91 are more suitable than B3LYP for calculating electronic absorption spectra. The features of electronic absorption spectra were assigned on account of the qualitative agreement between the experiment and the calculations. The absorption bands in visible and near-UV region are related to photoinduced electron transfer processes, and the diphenylaniline group is major chromophore that contributed to the sensitization, and the interfacial electron transfer are electron injection processes from the excited dyes to the semiconductor conduction band. Compared with the similar dye D5, the good performance of TA-St-CA in dye-sensitized solar cells may be resulted from the higher energy level of the lowest unoccupied molecular orbital and the larger oscillator strengths for the most excited states with intramolecular electron transfer character.

Risk Factors for Cervical Cancer in Rural Areas of Wuhan China: a Matched Case-control Study

Zhang, Bin,Zhou, Ai-Fen,Zhu, Chang-Cai,Zhang, Ling,Xiang, Bing,Chen, Zhong,Hu, Rong-Hua,Zhang, Ya-Qi,Qiu, Lin,Zhang, Yi-Ming,Xiong, Chao-Du,Du, Yu-Kai,Shi, Yu-Qin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Cervical cancer is a serious public health problem in developing countries. We investigated possible risk factors for cervical cancer in rural areas of Wuhan China using a matched case-control study with 33 women diagnosed with cervical cancer and 132 healthy women selected from the same area as matched controls. A questionnaire, which included questions about general demography conditions, environmental and genetic factors, the first sexual intercourse, first marriage age, age at first pregnancy, pregnancy first child's age, female personal health history, social psychological factors, dietary habits, smoking and alcohol status and other living habits was presented to all participants. At the same time, HPV infection of every participant was examined in laboratory testing. Results showed HPV infection (P<0.000, OR=23.4) and pregnancy first child's age (P<0.000, OR=13.1) to be risk factors for cervical cancer. Menopause (P=0.003, OR=0.073) was a protective factor against cervical cancer. However, there was no indication of associations of environmental (drinking water, insecticide, disinfectant) genetic (cancer family history), or life-style factors (smoking status, alcohol status, physical training, sleep quality), including dietary habits (intake of fruit and vegetable, meat, fried food, bean products and pickled food) or social psychological factors with cervical cancer. The results suggest that the risk of cervical cancer in Chinese rural women may be associated with HPV infection, menopause and the pregnancy first child's age.

Nonlinear Optical Properties of Silicon Nanocrystals Grown by Using a SiOx/SiO2 Superlattice Approach

Rong-Jun Zhang,Wei-Jie Lu,Qing-Yuan Cai,Wei-Xi Zhou,Yu-Xiang Zheng,Liang-Yao Chen,Hui Zhou,Shi-Xiong Qian,Se-Young Seo 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.4

The nonlinear optical properties have been studied using the Z-scan technique for silicon nanocrystals embedded in a SiO2 matrix formed by high-temperature annealing of SiOx/SiO2 superlattices grown by thermal evaporation. A mode-locked Ti:sapphire laser system producing 140-fs-long pulses at 800 nm was used as the optical source for the Z-scan measurements. The nonlinear refractive index and the nonlinear absorption coefficient of the silicon nanocrystals were found to be 1.2 × 10−13 cm2/W and 1.5 × 10−9 cm/W, respectively, and to be strongly enhanced compared to those of bulk silicon. Such enhancement of the nonlinear optical properties is considered to be due to the quantum confinement effect of silicon nanocrystals.

Horizon supertranslation and degenerate black hole solutions

Cai, Rong-Gen,Ruan, Shan-Ming,Zhang, Yun-Long Institute of Physics Pub 2016 The journal of high energy physics Vol.2016 No.9

Topological non-Fermi liquid

Cai, Rong-Gen,Qi, Yong-Hui,Wu, Yue-Liang,Zhang, Yun-Long American Physical Society 2017 Physical Review D Vol.95 No.12

<P>The (2 + 1)-dimensional non-Fermi liquid (NFL) has a dual description in the (3 + 1)-dimensional anti-de Sitter (AdS) spacetime. We begin with a dyonic Reissner-Nordstrom (RN) black brane background, and consider the bulk Dirac fermion field coupled with the background U(1) gauge field, as well an intrinsic axial gauge field which is induced by chiral anomaly. The axial gauge field is effectively induced from the topological term in the bulk, which would lead to nontrivial effects on the boundary NFL. We study these effects through calculating the retarded Green's functions of the dual NFL holographically, in both analytical and numerical approaches. We also obtain correlation functions in the low frequency limit at zero and finite temperatures, as well as the dispersion spectrum of the Dirac cones, Fermi arc of the surface states, which can be related with the experiment.</P>

Emergent dark matter in late time universe on holographic screen

Cai, Rong-Gen,Sun, Sichun,Zhang, Yun-Long Institute of Physics Pub 2018 The journal of high energy physics Vol.2018 No.10

Effects of Impeller Geometry on the 11α-Hydroxylation of Canrenone in Rushton Turbine-Stirred Tanks

( Shaofeng Rong ),( Xiaoqing Tang ),( Shimin Guan ),( Botao Zhang ),( Qianqian Li ),( Baoguo Cai ),( Juan Huang ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.6

The 11α-hydroxylation of canrenone can be catalyzed by Aspergillus ochraceus in bioreactors, where the geometry of the impeller greatly influences the biotransformation. In this study, the effects of the blade number and impeller diameter of a Rushton turbine on the 11α-hydroxylation of canrenone were considered. The results of fermentation experiments using a 50 mm four-blade impeller showed that 3.40% and 11.43% increases in the conversion ratio were achieved by increasing the blade number and impeller diameter, respectively. However, with an impeller diameter of 60 mm, the conversion ratio with a six-blade impeller was 14.42% lower than that with a four-blade impeller. Data from cold model experiments with a large-diameter six-blade impeller indicated that the serious leakage of inclusions and a 22.08% enzyme activity retention led to a low conversion ratio. Numerical simulations suggested that there was good gas distribution and high fluid flow velocity when the fluid was stirred by large-diameter impellers, resulting in a high dissolved oxygen content and good bulk circulation, which positively affected hyphal growth and metabolism. However, a large-diameter six-blade impeller created overly high shear compared to a large-diameter four-blade impeller, thereby decreasing the conversion ratio. The average shear rates of the former and latter cases were 43.25 s^-1 and 35.31 s^-1, respectively. We therefore concluded that appropriate shear should be applied in the 11α-hydroxylation of canrenone. Overall, this study provides basic data for the scaled-up production of 11α-hydroxycanrenone.

Stigmast-4-en-6β-ol-3-one decreases viability and induces apoptosis and ferroptosis in liver cancer cells by reducing E2F1

Zhiyun Zhang,Jian Wang,Weiping Wan,Zhengchao Shen,Aixue Zuo,Rong Chen,Qinyi Wu,Enli Cai,Feng Huang,Rongping Zhang,Xinan Shi 한국통합생물학회 2023 Animal cells and systems Vol.27 No.1

Hepatocellular carcinoma (HCC) is a frequently occurring malignant gastrointestinal cancer. The 5-year survival rate of HCC is still below 8%, and thus, identifying more effective therapeutic methodsis needed. Here, we evaluated the effects of Stigmast-4-en-6β-ol-3-one (S463) on the viability andcolony formation of liver cancer cells. S463 treatment decreased the viability and inducedapoptosis and ferroptosis in liver cancer cells, and also increased cellular malondialdehyde(MDA) and lipid peroxidation levels. In S463 treated cells, the expression level of Bax wasincreased, and the expression level of GPX4 was reduced, and the cleavage of PARP wasimproved. We also found that S463 treatment downregulated E2F1 and upregulated p53 atboth the mRNA and protein levels. Importantly, rescue experiments revealed thatoverexpression of E2F1 partially restored S463-induced Bax and p53 upregulation and GPX4downregulation and counteracted the S463-induced decrease in cell viability and colonyformation and the S463-induced increase in MDA and lipid peroxidation levels. Our findingssuggest that S463 significantly inhibits viability and colony formation and induces apoptosisand ferroptosis in liver cancer cells via E2F1.

The Prevalence of Post-Traumatic Stress Disorder in the General Population during the COVID-19 Pandemic: A Systematic Review and Single-Arm Meta-Analysis

Liqing Zhang,Rong Pan,Yixian Cai,Jiyang Pan 대한신경정신의학회 2021 PSYCHIATRY INVESTIGATION Vol.18 No.5

Objective To investigate the prevalence of post-traumatic stress disorder (PTSD) in the general population during the COVID-19 pandemic by a systematic review and single-arm meta-analysis.Methods CNKI, PubMed, EMBASE, and MEDLINE were searched to collect literature on the prevalence of PTSD in the general population during the epidemic. The retrieval time is from the database construction to 31/08/2020. Meta-analysis was performed on the included articles by using Review Manger 5.3 and Stata 16.0 software.Results The prevalence of PTSD in the general population during the COVID-19 pandemic was 15% (95% CI: 11–21%, p<0.001).Conclusion The COVID-19 pandemic brought certain mental pain to general population, leading to a rise in the incidence of PTSD in a short time.

Senescence as A Consequence of Ginsenoside Rg₁ Response on K562 Human Leukemia Cell Line

Liu, Jun,Cai, Shi-Zhong,Zhou, Yue,Zhang, Xian-Ping,Liu, Dian-Feng,Jiang, Rong,Wang, Ya-Ping Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.12

Aims and Background: Traditional chemotherapy strategies for human leukemia commonly use drugs based on cytotoxicity to eradicate cancer cells. One predicament is that substantial damage to normal tissues is likely to occur in the course of standard treatments. Obviously, it is urgent to explore therapies that can effectively eliminate malignant cells without affecting normal cells. Our previous studies indicated that ginsenoside $Rg_1$ ($Rg_1$), a major active pharmacological ingredient of ginseng, could delay normal hematopoietic stem cell senescence. However, whether $Rg_1$ can induce cancer cell senescence is still unclear. Methods: In the current study, human leukemia K562 cells were subjected to $Rg_1$ exposure. The optimal drug concentration and duration with K562 cells was obtained by MTT colorimetric test. Effects of $Rg_1$ on cell cycle were analyzed using flow cytometry and by SA-${\beta}$-Gal staining. Colony-forming ability was measured by colony-assay. Telomere lengths were assessed by Southern blotting and expression of senescence-associated proteins P21, P16 and RB by Western blotting. Ultrastructural morphology changes were observed by transmission electron microscopy. Results: K562 cells demonstrated a maximum proliferation inhibition rate with an $Rg_1$ concentration of $20{\mu}\;mol{\cdot}L^{-1}$ for 48h, the cells exhibiting dramatic morphological alterations including an enlarged and flat cellular morphology, larger mitochondria and increased number of lysosomes. Senescence associated-${\beta}$-galactosidase (SA-${\beta}$-Gal) activity was increased. K562 cells also had decreased ability for colony formation, and shortened telomere length as well as reduction of proliferating potential and arrestin $G_2$/M phase after $Rg_1$ interaction. The senescence associated proteins P21, P16 and RB were significantly up-regulated. Conclusion: Ginsenoside $Rg_1$ can induce a state of senescence in human leukemia K562 cells, which is associated with p21-Rb and p16-Rb pathways.