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.

Design and Analysis of an Active Balancing Mechanism for a Vertical Axis Washing Machine

Hai-Wei Chen,Xun-Ting Yuan,Zhen Sun,Qiu-Qi Mou,Ming Xiong,Wei-Hua Wang 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.7

In recent years, active balancing of washing machines has drawn much attention from manufactures. This paper proposes a novel active balancing mechanism for vibration suppression of a vertical axis washing machine which employs water for counteracting the unbalanced laundry. At first, a novel structure with two balancing planes sharing only one set of nozzles for injecting water is designed and the balancing capability of the structure is analyzed. Then, a dynamic model of the active balancing system is constructed. Vibration characteristics of the system including changes of the vibration amplitude and phase angle under different influences are studied. After that, a strategy for identifying the imbalance is proposed and an active control method is designed. At last, a washing machine armed with the active mechanism is manufactured. Both a fixed eccentric block and a pile of randomly distributed laundry are used to test the balancing effect. The results show that lateral vibrations of the washer can be greatly reduced by the active mechanism. Due to the simplicity of the structure and the satisfactory balancing effect, the mechanism proposed has a big potential to be employed in future washing machines.

Inhibition of cancer cell growth and migration by dihydroxynaphthyl aryl ketones

Wei Xiong,Yun-Feng Li,Shan Liu,Ting Chen,Hong-Tao Zhang,Zhi-Bin Yang,Ying-Ying Ding,De-Pei Gao,Guan-Shun Wang,Jian Dong,Jian Dong 대한독성 유전단백체 학회 2016 Molecular & cellular toxicology Vol.12 No.4

Dihydroxynaphthyl aryl ketones 1-5 exhibit activity as tubulin polymerization inhibitors by targeting the colchicine binding site of microtubules making them potential anticancer drugs. Therefore, analogues 1-5 have been evaluated for their cytotoxic activity against the cancer cell lines DU-145 (prostate), T24 (bladder) and MCF-7 (breast). notable differences in biological activity were observed for compounds 1-5, most likely related to the nature of the aryl substituent bonded to the carbonyl group. among the tested compounds, only compound 5 showed selectivity for cancer cells over healthy, non-transformed cells. T24 cancer cells treated with compound 5 presented a concentration-dependent decrease in cell proliferation and a loss of migration ability. The cytotoxicity of compounds 1-5 on the selected cell-based assays is discussed in terms of it lipophilicity and polarizability parameters.

Vasodilation Effect of 2-benzyl-5-hydroxy-6-methoxy-3, 4-dihydroisoquinolin- 1-one

Wei-Qi,Yong-Xiao Cao,Zhi-Zheng Xiong,Ting-Ting Chen,Xiao-Yan Gao,Hang Yu,San-Qi Zhang 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.8

A 2-Benzyl-5-hydroxy-6-methoxy-3, 4-dihydroisoquinolin-1-one (ZC2) is a newly synthesized isoquinolinone compound. Its effect on vasodilation was evaluated in the present study. Isometric tension of rat artery rings was recorded by a sensitive myography system in vitro. The results showed that ZC2 relaxed rat mesenteric arteries pre-contracted by KCl, phenylephrine and 9, 11- dideoxy- 11α, 9α-epoxymethano-prostaglandin F2α (U46619), and abdominal aorta pre-contracted by KCl in a concentration-dependent manner. The ZC2-induced vasodilation was not affected by an endothelium denudation. ZC2 rightwards shifted the concentration-contraction curves, induced by KCl, phenylephrine, and 5-hydroxytryptamine (5-HT) in a non-parallel manner, which suggests that the vasodilation effects are most likely via voltage-dependent calcium channel (VDCC) and receptor-operated calcium channel (ROCC). Moreover, in Ca2+-free medium, ZC2 concentration-dependently depressed the vasoconstrictions induced by phenylephrine and CaCl2, and decreased a contractile response induced by caffeine, which indicates a role of extracellular Ca2+ influx inhibition through VDCC and ROCC, and intracellular Ca2+ release from Ca2+ store via the ryanodine receptors. Glibenclamide did not affect the vasodilation induced by ZC2, suggesting that ATP sensitive potassium channel is not involved in the vasodilation. The results indicate that ZC2 induces vasodilation by inhibiting the VDCC and ROCC, and receptormediated Ca2+ influx and release. The inhibition of intracellular Ca2+ release may be mediated via the ryanodine receptors.

Radiofrequency Ablation Combined with Transcatheter Arterial Chemoembolization Therapy Versus Surgical Resection for Hepatocellular Carcinoma within the Milan Criteria: A Meta-Analysis

Wei-dong Wang,Li-hua Zhang,Jia-Yan Ni,Xiong-ying Jiang,Dong Chen,Yao-ting Chen,Hong-liang Sun,Jiang-hong Luo,Lin-feng Xu 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.4

Objective: To meta-analytically compare combined transarterial chemoembolization (TACE) plus radiofrequency ablation (RFA) and surgical resection (SR) for the treatment of hepatocellular carcinoma (HCC) within the Milan criteria. Materials and Methods: PubMed, Medline, Embase, and Cochrane Library were searched for studies comparing these two therapies that were published between January 2006 and August 2017. Overall survival rate (OS), recurrence-free survival rate (RFS), major complications and the average length of hospital stay were compared between these two therapies. Metaanalytic pooled odds ratio (OR) was calculated using TACE plus RFA as the base category. Results: Seven case-control studies and one randomized trial were identified. Meta-analytic results revealed that, compared with SR, TACE plus RFA had significantly higher 1-year OS (OR for survival = 0.50, p = 0.009) and lower major complications (OR = 1.88, p = 0.02) after therapy. Three studies reported on the length of hospital stay. The average length ± standard deviation reported in individual studies for SR and TACE plus RFA groups was 19.8 ± 8.4 days and 7.4 ± 2.2 days, respectively; 18.7 ± 4.9 days and 11.5 ± 6.9 days, respectively; and 16.6 ± 6.7 days and 8.5 ± 4.1 days, respectively (p < 0.0001 for all studies). Three or 5-year OS and 1-, 3-, or 5-year RFS did not significantly differ between the two therapies. Conclusion: Combined TACE plus RFA may be an alternative to SR for the treatment of patients with HCC within Milan the criteria. Non-randomized design in most of the original studies was a limitation.

Cancer Registration in the Peoples Republic of China

Wei, Kuang-Rong,Chen, Wan-Qing,Zhang, Si-Wei,Liang, Zhi-Heng,Zheng, Rong-Shou,Ou, Zhi-Xiong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

The current situation of cancer registration in China was systematically reviewed. So far, cancer registration in China has been making a great progress in the following aspects: the number of cancer registries and covered population have increased dramatically; a registration network has been established and completed gradually; regulations and rules improved remarkably; more attention is being paid by every level of government; a lot of registration software has been created and financial support ensured. However, we are still facing some problems and challenges, such as no stable groups of registrars, shortage of training opportunities, poor data quality, insufficient utilization and lack of multidisciplinary mechanisms, so that the cancer registration system still needs to be enhanced and improved. Along with the development of economy, science and information technology, methods and patterns of cancer registration is changing. It is to be expected that cancer registration will be automatic, nationwide and integrated with community healthcare in the near future.

Static strengths of preloaded circular hollow section stub columns strengthened with carbon fiber reinforced polymer

Chen Wei,Yong-Bo Shao,Mostafa Fahmi Hassanein,Chuannan Xiong,Hongmei Zhu 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.4

To investigate the load bearing capacity of axially preloaded circular hollow section (CHS) stub columns strengthened by carbon fiber reinforced polymer (CFRP), theoretical analysis is carried out. The yield strength and the ultimate strength of a CFRP strengthened preloaded CHS stub column are determined at the yielding of the CHS tube and at the CFRP fracture, respectively. Theoretical models are proposed and corresponding equations for calculating the static strengths, including the yield strength and the ultimate strength, are presented. Through comparison with reported experimental results, the theoretical predictions on the static strengths are proved to be accurate. Through finite element (FE) analyses, parametric studies for 258 models of CFRP strengthened preloaded CHS stub columns are conducted by considering different values of tube diameter, tube thickness, CFRP layer and preloading level. The static strengths of the 258 models predicted from presented equations are proved to be in good agreement with FE simulations when the diameter-to-thickness ratio is less than 90ε 2 . The parametric study indicates that the diameter and the thickness of the steel tube have great effects on CFRP strengthening efficiency, and the recommended ranges of the diameter and the thickness are proposed.

Controlling the Thickness of Thermally Expanded Films of Graphene Oxide

Chen, Xianjue,Li, Wei,Luo, Da,Huang, Ming,Wu, Xiaozhong,Huang, Yuan,Lee, Sun Hwa,Chen, Xiong,Ruoff, Rodney S. American Chemical Society 2017 ACS NANO Vol.11 No.1

<P>'Paper-like' film material made from stacked and overlapping graphene oxide sheets can be exfoliated (expanded) through rapid heating, and this has until now been done with no control of the final geometry of the expanded graphene oxide material, i.e., the expansion has been physically unconstrained. (As a consequence of the heating and exfoliation, the graphene oxide is 'reduced', i.e., the graphene oxide platelets are deoxygenated to a degree.) We have used a confined space to constrain the expanding films to a controllable and uniform thickness. By changing the gap above the film, the final thickness of expanded films prepared from, e.g., a 10 mu m-thick graphene oxide film, could be controlled to values such as 20, 30, 50, or 100 mu m. When the expansion of the films was unconstrained, the final film was broken into pieces or had many cracks. In contrast, when the expansion was constrained, it never cracked or broke. Hot pressing the expanded reduced graphene oxide films at 1000 degrees C yielded a highly compact structure and promoted graphitization. Such thickness-controlled expansion of graphene oxide films up to tens or hundreds of times the original film thickness was used to emboss patterns on the films to produce areas with different thicknesses that remain connected 'in plane'. In another set of experiments, we treated the original graphene oxide film with NaOH before its controlled expansion resulted in a different structure featuring uniformly distributed pores and interconnected layers as well as simultaneous activation of the carbon.</P>

Molecular Identification of Microbial Community in Chinese Douchi During Post-fermentation Process

Tingtao Chen,Shunqiang Xiong,Shuying Jiang,Mengjuan Wang,Qinglong Wu,Hua Wei 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.6

To track changes in dynamic microbial communities during post-fermentation process, traditional culture method, and denaturing gradient gel electrophoresis (DGGE) were used to study the number and species of dominant microorganisms in douchi. The result of culturedependent method showed that the microbial number changed slightly since the 4^th day while the DGGE indicated that the really steady-state was achieved from the 10^th day. In addition, Lactococcus lactis subsp.,Staphylococcus lentus, and 2 uncultured bacterium were identified to occupy the dominant positions in bacterial DGGE pattern, and Bacillus thermoamylovorans, Bacillus subtilis, Enterobacter spp., and Absidia corymbifera,Pichia guilliermondii, Pichia farinose were also detected from Bacillus and fungal DGGE patterns, respectively. In conclusion, some pathogenic microorganisms involving in the douchi fermentation had been detected throughout the post-fermentation process, and the combination of culturedependent and –independent method was proved to be effective in profiling microbial diversity.

Efficient conversion of fructose to 5-[(formyloxy)methyl]furfural by reactive extraction and in-situ esterification

Caixia Xiong,Yong Sun,Juan Du,Wei Chen,Zhihao Si,He Gao,Xing Tang,Xianhai Zeng 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.6

5-[(Formyloxy)methyl]furfural (FMF), an analogue of 5-(hydroxymethyl)furfural (HMF) is becoming more attractive due to its superior stability and hydrophobicity, which make it easier to refineand store. In the present study, FMF was produced from fructose by one-pot approach in pure formic acid media or by a two-step approach via HMF in choline chloride (ChCl)/fructose deep eutectic solvents (DES) system. A favorable FMF yield of 63.22% was reached by two-step approach. In addition, the effects of reaction parameters, such as temperature and acidity, on preparation of FMF from fructose were systematically investigated. The dehydration of fructose into HMF was confirmed as the rate-controlling step in the consecutive reaction. Ultimately, the separation and purification procedures of FMF were put forward. The FMF with a purity of 98.8% was obtained finally. Meanwhile, the FMF purified by saturated sodium bicarbonate solution showed an excelled storage stability.