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| 1 | Expression of NASG gene and its role in human nasopharyngeal homogenous tissue cells显示文摘Background The NASG gene has been confirmed as a tumor-suppressor gene candidate related to nasopharyngeal carcinoma (NPC) by previous studies. We further investigated the expression and the role of NASG in the homogeneous tissue cells by microdissecting the samples of tissue from human NPC, and introduced a new way to study the expression of specific genes in tumor tissue. Methods The RNAlater reagent was used to preserve the samples of tissue from the nasopharynx of NPC patients. The samples were microdissected to harvest the homogeneous tissue cells and then total RNA was isolated from them. The antisense RNA (aRNA) was amplified from the total RNA by “ in vitro transcription (IVT)”. We investigated NASG expression in the homogeneous tumor cells of NPC (22 samples) and compared it with that in the pure epithelial pillar cells of normal nasopharyngeal (10 samples) by semi-quantitative reverse transcription-polymerase chain reaction (sqRT-PCR). Results The high quality total RNA could be harvested from the microdissected homogeneous tissue cells of the nasopharynx, then sufficient aRNA was derived from it. NASG gene expression was identified using aRNA by sqRT-PCR and showed that there was significant difference between the average value of case groups and that of control group ( t =-5.275, df =30, P <0.001). The NASG gene in the subgroups WHOII tended to express lower levels than those in the subgroup WHOⅢ although this difference was not statistically siginificant ( t =-1.584, df =20, P = 0.129>0.05). Conclusions Microdissection was an effective method to obtain the homogeneous tissue cells of nasopharyngeal tissue (including the samples of NPC and non-NPC) in our study. Sufficient aRNA from amplifiying total RNA could be used in sqRT-PCR to analyse the expression of NASG in the pure tissue cells. NASG should be a tumor-suppression gene candidate regarding to NPC. | LIUZhong-qi TIANYong-quan PENGCong HUYong-fang ZHOUMing OUYANGJue LIXiao-ling LIUHua-ying ZHANGBi-cheng LIGui-yuan | 2005 | Chinese Medical Journal2005，，13： | 3 |
| 2 | A POSITIVITY-PRESERVING FINITE ELEMENT METHOD FOR QUANTUM DRIFT-DIFFUSION MODEL显示文摘In this paper,we propose a positivity-preserving finite element method for solving the three-dimensional quantum drift-diffusion model.The model consists of five nonlinear elliptic equations,and two of them describe quantum corrections for quasi-Fermi levels.We propose an interpolated-exponential finite element(IEFE)method for solving the two quantum-correction equations.The IEFE method always yields positive carrier densities and preserves the positivity of second-order differential operators in the Newton linearization of quantum-correction equations.Moreover,we solve the two continuity equations with the edge-averaged finite element(EAFE)method to reduce numerical oscillations of quasi-Fermi levels.The Poisson equation of electrical potential is solved with standard Lagrangian finite elements.We prove the existence of solution to the nonlinear discrete problem by using a fixed-point iteration and solving the minimum problem of a new discrete functional.A Newton method is proposed to solve the nonlinear discrete problem.Numerical experiments for a three-dimensional nano-scale FinFET device show that the Newton method is robust for source-to-gate bias voltages up to 9V and source-to-drain bias voltages up to 10V. | Pengcong Mu Weiying Zheng | 2023 | Journal of Computational Mathematics2023，41，5： | 0 |
| 3 | Microbially-mediated formation of Ca-Fe carbonates during dissimilatory ferrihydrite reduction:Implications for the origin of sedimentary ankerite显示文摘The origin of sedimentary dolomite has become a long-standing problem in the Earth Sciences.Some carbonate minerals like ankerite have the same crystal structure as dolomite,hence their genesis may provide clues to help solving the dolomite problem.The purpose of this study was to probe whether microbial activity can be involved in the formation of ankerite.Bio-carbonation experiments associated with microbial iron reduction were performed in batch systems with various concentrations of Ca^(2+)(0–20 mmol/L),with a marine iron-reducing bacterium Shewanella piezotolerans WP3 as the reaction mediator,and with lactate and ferrihydrite as the respective electron donor and acceptor.Our biomineralization data showed that Ca-amendments expedited microbially-mediated ferrihydrite reduction by enhancing the adhesion between WP3 cells and ferrihydrite particles.After bioreduction,siderite occurred as the principal secondary mineral in the Ca-free systems.Instead,Ca-Fe carbonates were formed when Ca^(2+)ions were present.The CaCO_(3) content of microbially-induced Ca-Fe carbonates was positively correlated with the initial Ca2+concentration.The Ca-Fe carbonate phase produced in the 20 mmol/L Ca-amended biosystems had a chemical formula of Ca_(0.8)Fe_(1.2)(CO_(3))_(2),which is close to the theoretical composition of ankerite.This ankeritelike phase was nanometric in size and spherical,Ca-Fe disordered,and structurally defective.Our simulated diagenesis experiments further demonstrated that the resulting ankerite-like phase could be converted into ordered ankerite under hydrothermal conditions.We introduced the term“proto-ankerite”to define the Ca-Fe phases that possess near-ankerite stoichiometry but disordered cation arrangement.On the basis of the present study,we proposed herein that microbial activity is an important contributor to the genesis of sedimentary ankerite by providing the metastable Ca-Fe carbonate precursors. | Deng LIU Jinpeng CAO Shanshan YANG Yating YIN Pengcong WANG Dominic PAPINEAU Hongmei WANG Xuan QIU Genming LUO Zongmin ZHU Fengping WANG | 2024 | Science China Earth Sciences2024，67，1： | 0 |
| 4 | Negative correlation between acetyl-CoA acyltransferase 2 and cetuximab resistance in colorectal cancer显示文摘The emergence of anti-EGFR therapy has revolutionized the treatment of colorectal cancer(CRC).However,not all patients respond consistently well.Therefore,it is imperative to conduct further research to identify the molecular mechanisms underlying the development of cetuximab resistance in CRC.In this study,we find that the expressions of many metabolism-related genes are downregulated in cetuximab-resistant CRC cells compared to their sensitive counterparts.Specifically,acetyl-CoA acyltransferase 2(ACAA2),a key enzyme in fatty acid metabolism,is downregulated during the development of cetuximab resistance.Silencing of ACAA2 promotes proliferation and increases cetuximab tolerance in CRC cells,while overexpression of ACAA2 exerts the opposite effect.RTK-Kras signaling might contribute to the downregulation of ACAA2 expression in CRC,and ACAA2 predicts CRC prognosis in patients with Kras mutations.Collectively,our data suggest that modulating ACAA2 expression contributes to secondary cetuximab resistance in Kras wild-type CRC patients.ACAA2 expression is related to Kras mutation and demonstrates a prognostic role in CRC patients with Kras mutation.Thus,ACAA2 is a potential target in CRC with Kras mutation. | Yitao Yuan Xun Sun Mengling Liu Suyao Li Yu Dong Keshu Hu Jiayu Zhang Bei Xu Sining Ma Hesheng Jiang Pengcong Hou Yufu Lin Lu Gan Tianshu Liu | 2023 | Acta Biochimica et Biophysica Sinica2023，55，9： | 0 |
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