Biodegradable cross-linked poly(L-lactide-co-e-caprolactone) networks for ureteral stent formed by gamma irradiation under vacuum

Xiliang Liu,Song Liu,Youkun Fan,Jin Qi,Xin Wang,Wei Bai,Dongliang Chen,Chengdong Xiong,Lifang Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-

The poly(L-lactide-co-e-caprolactone) (PLCL) ureteral stent creeps and loses shape stability, increasingthe risk of stent tube dislocation. The rubbery biodegradable cross-linked PLCL networks were preparedthrough gamma irradiation under vacuum in the presence of trimethylolpropane triacrylate (TMPTA),pentaerythritol tetraacrylate (PET4A), and pentaerythritol triacrylate (PETA). At a standard sterilizationdose of 25 kGy, the gel content and network density of PLCL networks increased with increasingcrosslinking agent content (1, 3, 5, 7 wt%), and crosslinking efficiency decreased in the order ofPETA > PET4A > TMPTA. The average molecular weight (Mc ) between two crosslinks ranged from 2000to 105 g/mol. To perform the beneficial semi-interpenetrated polymer network and characterized bythe principle, the networks were processed in several doses (25, 50, 75, 100, and 125 kGy). In place ofthe Charlesby-Pinner equation, the irradiation cross-linking followed the Chen-Liu-Tang equation. ThePLCL network with 7 wt% PETA had a gel fraction of 83%, tensile strength of 34.7 MPa, and tensile setvalue as low as 5%. Furthermore, degradation in vitro was slowed down. Thus, PLCL networks with appropriateelasticity and flexibility, inherent biodegradability, and excellent biocompatibility can provide apromising alternative method for soft tissue repair engineering, such as ureteral stents.

Dissipative Particle Dynamics Simulation on the Formation Process of CeO₂ Nanoparticles in Alcohol Aqueous Solutions

Zhang, Qi,Zhong, Jing,Yang, Bao-Zhu,Huang, Wei-Qiu,Chen, Ruo-Yu,Liao, Jun-Min,Gu, Chi-Ruei,Chen, Cheng-Lung Korean Chemical Society 2012 대한화학회지 Vol.56 No.4

Dissipative particle dynamics (DPD) was carried out to study the nucleation and crystal growth process of $CeO_2$ nanoparticles in different alcohol aqueous solutions. The results showed that the nucleation and crystal growth process of $CeO_2$ can be classified into three stages: nuclei growth, crystal stabilization and crystal aggregation except the initial induction stage, which could be reproduced by collecting simulation results after different simulation time. Properly selecting the sizes of $CeO_2$ and water bead was crucial in the simulation system. The influence of alcohol type and content in solutions, and precipitation temperature on the particle dimension were investigated in detail and compared with the experimental results. The consistency between simulation results and experimental data verify that the simulation can reproduce the macroscopic particle aggregation process. The effect of solvent on the nucleation and crystal growth of $CeO_2$ nanoparticles are different at three stages and can not be simply described by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory or nucleation thermodynamics theory. Our work demonstrated that DPD methods can be applied to study nanoparticle forming process.

Serum miR-19a Predicts Resistance to FOLFOX Chemotherapy in Advanced Colorectal Cancer Cases

Chen, Qi,Xia, Hong-Wei,Ge, Xiao-Jun,Zhang, Yu-Chen,Tang, Qiu-Lin,Bi, Feng Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Background: Colorectal cancer is the fourth most common cancer worldwide and the second leading cause of cancer-related death. FOLFOX is the most common regimen used in the first-line chemotherapy in advanced colorectal cancer, but only half of the patients respond to this regimen and we have almost no clue in predicting resistance in such first-line application. Methods: To explore the potential molecular biomarkers predicting the resistance of FOLFOX regimen as the first-line treatment in advanced colorectal cancer, we screened microRNAs in serum samples from drug-responsive and drug-resistant patients by microarrays. Then differential microRNA expression was further validated in an independent population by reverse transcription and quantitative real-time PCR. Results: 62 microRNAs expressing differentially with fold-change >2 were screened out by microarray analysis. Among them, 5 (miR-221, miR-222, miR-122, miR-19a, miR-144) were chosen for further validation in an independent population (N=72). Our results indicated serum miR-19a to be significantly up-regulated in resistance-phase serum (p=0.009). The ROC curve analysis showed that the sensitivity of serum miR-19a to discriminate the resistant patients from the response ones was 66.7%, and the specificity was 63.9% when the AUC was 0.679. We additionally observed serum miR-19a had a complementary value for cancer embryonic antigen (CEA). Stratified analysis further revealed that serum miR-19a predicted both intrinsic and acquired drug resistance. Conclusions: Our findings confirmed aberrant expression of serum miR-19a in FOLFOX chemotherapy resistance patients, suggesting serum miR-19a could be a potential molecular biomarker for predicting and monitoring resistance to first-line FOLFOX chemotherapy regimens in advanced colorectal cancer patients.

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.

Experiment and molecular simulation for liquid phase adsorption of triethylenetetramine on activated carbon: equilibrium, kinetics, thermodynamics and molecular behavior

Qi Zhang,Xiang C. Ma,Chang He,Qing L. Chen,Bing J. Zhang 한국탄소학회 2023 Carbon Letters Vol.33 No.7

Modification of the surface of raw activated carbon using chemical solvents can significantly improve the adsorption performance of activated carbon. Triethylenetetramine is one of the most important chemical solvents used to modify raw activated carbon for formaldehyde removal indoor. We conducted the liquid impregnation experiments at different initial concentrations, temperatures, adsorbent dosage and time ranges to fully investigate the adsorption of triethylenetetramine on the surface of raw activated carbon for modification. We found that the Langmuir isotherm model and pseudo-first-order kinetic model fit quite well with the experimental data and the R2 are 0.9883 and 0.9954, respectively. The theoretical maximum adsorption capacity is 166.67 mg/g. The change in Gibbs free energy (ΔG0), enthalpy change (ΔH0) and entropy change (ΔS0) were also calculated to study the direction and driving force of the liquid adsorption process. In order to understand the adsorption process at the molecular level, a new activated carbon model based on the actual physical and chemical properties of activated carbon was carefully established in the Materials Studio to simulate the liquid-phase adsorption. The pore structure, elemental composition, functional group content, density, pore volume, and porosity of the activated carbon model converge close to the actual activated carbon and the adsorption isotherms obtained from the simulation agree well with the experimental results. The results show that the adsorption of triethylenetetramine on activated carbon is a spontaneous, endothermic and monolayer physical adsorption process.

AtHAP3b Plays a Crucial Role in the Regulation of Flowering Time in Arabidopsis during Osmotic Stress

Chen, Nai-Zhi,Zhang, Xiu-Qing,Wei, Peng-Cheng,Chen, Qi-Jun,Ren, Fei,Chen, Jia,Wang, Xue-Chen Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.6

The HAP complex has been found in many eukaryotic organisms. HAP recognizes the CCAAT box present in the promoters of 30% of all eukaryotic genes. The HAP complex consists of three subunits - HAP2, HAP3 and HAP5. In this paper, we report the biological function of the AtHAP3b gene that encodes one of the HAP3 subunits in Arabidopsis. Compared with wild-type plants, hap3b-1 and hap3b-2 mutants exhibited a delayed flowering time under long-day photoperiod conditions. Moreover, the transcription levels of FT were substantially lower in the mutants than in the wild-type plants. These results imply that AtHAP3b may function in the control of flowering time by regulating the expression of FT in Arabidopsis. In a subsequent study, AtHAP3b was found to be induced by osmotic stress. Under osmotic stress conditions, the hap3b- 1 and hap3b-2 mutants flowered considerably later than the wild-type plants. These results suggest that the AtHAP3b gene plays more important roles in the control of flowering under osmotic stress in Arabidopsis.

Electrospun Polyphenylquinoxaline Ultrafine Non-woven Fibrous Membranes with Excellent Thermal and Alkaline Resistance: Preparation and Characterization

Chen-yu Guo,Lu-meng Yin,Jin-gang Liu,Xin-ke Wang,Na Zhang,Lin Qi,Yan Zhang,Xiao Wu,Xiu-min Zhang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.12

A series of polyphenylquinoxaline (PPQ) ultrafine non-woven fibrous membranes have been first successfullyprepared via the electrospinning procedure with the soluble PPQ solutions as the starting materials. For this purpose, variousorgano-soluble PPQ resins were synthesized via the one-step high temperature polycondensation procedure from thearomatic ether-bridged bis(α-diketone) and bis(o-diamine) monomers. Flexible ether linkages and pendant bulky phenylsubstituents endowed the PPQ resins good solubility in polar aprotic solvents. The high-molecular-weight PPQ resins weredissolved in N-methyl-2-pyrrolidone (NMP) to afford the PPQ electrospinning solution except PPQ-Ia derived from 4,4'-oxydibenzil (ODB) and 3,3'-diaminobenzidine (DAB) due to the limited solubility in the solvent. All the derived PPQultrafine non-woven fibrous membranes maintained good structure integrity after hydrolysis aging either at room temperature(25 oC) for 72 h or at refluxing temperature (100 oC) for 24 h in an aqueous sodium hydroxide (NaOH) solution at a solidcontent of 20 wt%. Comparatively, the polyimide (PI) reference electrospun membrane (PI-ref) derived from 1,2,4,5-pyrromellitic anhydride (PMDA) and 4,4'-oxydianiline (ODA) lost its original structure only after boiling in the same NaOHsolution within 3 h. In addition, the developed PPQ ultrafine non-woven fibrous membranes exhibited good thermal stabilitywith the 5 % weight loss temperatures (T5%) higher than 555.0 oC in nitrogen and glass transition temperatures (Tg) in therange of 248.1-266.1 oC, respectively.

Fabrication and Characterization of Vertically Aligned ZnO Nanorod Arrays via Inverted Monolayer Colloidal Crystals Mask

Cheng Chen,Taotao Ding,Zhiqiang Qi,Wei Zhang,Jun Zhang,Juan Xu,Jingwen Chen,Jiangnan Dai,Changqing Chen 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.4

The periodically ordered ZnO nanorod (NR) arrays have been successfully synthesized via a hydrothermal approach on thesilicon substrates by templating of the TiO2ring deriving from the polystyrene (PS) nanosphere monolayer colloidal crystals(MCC). With the inverted MCC mask, sol–gel-derived ZnO seeds could serve as the periodic nucleation positions for thesite-specific growth of ZnO NRs. The large-scale patterned arrays of single ZnO NR with good side-orientation can be readilyproduced. According to the experimental results, the as-integrated ZnO NR arrays showed an excellent crystal quality andoptical property, very suitable for optoelectronic applications such as stimulated emitters and ZnO photonic crystal devices.

Responses of Buried Pipelines to Tunnelling Underneath Considering Effect of Gap Formation: an Analytical Approach

Bing-qiang Zhang,Qi-wen Chen,Feng-wen Lai,Fu-Quan Chen,Bin-bin Qi 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

A gap formation underneath pipelines could be observed during tunneling beneath existing buried pipelines, thus altering the pipeline-soil interaction behavior. However, the most existing analytical approaches typically do a full contact assumption for brevity. For such purpose, we aim to present an analytical approach coupling the effect of gap formation underneath pipelines by considering the buried pipeline as an Euler-Bernoulli beam on tensionless foundation. The pipeline can be divided into three segments according to pipeline-soil interaction behavior, and then the bending behaviors of each segment are formulated. The deflection and bending moment of the pipeline caused by tunnelling underneath from the proposed approach are compared and validated with centrifuge testing data and existing analytical solutions. The effects of pipeline-soil stiffness ratio, pipeline buried depth, tunnel buried depth, tunneling induced volume loss, and tunnel-pipeline intersection angle on the pipeline responses are further discussed. The results indicate that gap formation underneath pipeline can be observed indeed for shallowly buried pipeline and/or larger pipeline-soil stiffness ratio. The proposed analytical approach provides a theoretical guideline to predict the responses of existing pipelines to tunnelling underneath.

AtHAP3b Plays a Crucial Role in the Regulation of Flowering Time in Arabidopsis during Osmotic Stress

Nai Zhi Chen,Xiu Qing Zhang,Peng Cheng Wei,Qi Jun Chen,Fei Ren,Jia Chen,Xue Chen Wang 한국생화학분자생물학회 (구 한국생화학회) 2007 BMB Reports Vol.40 No.6