Study on the pretreatment of poly(ether ether ketone)/multiwalled carbon nanotubes composites through environmentally friendly chemical etching and electrical properties of the chemically metallized composites
Zhai T.,Tianjin University of Technology |
Zhai T.,Tianjin University |
Di L.,Tianjin Medical College |
Yang D.,Tianjin University of Technology |
Yang D.,Tianjin University
ACS Applied Materials and Interfaces | Year: 2013
The high-volume resistivity and surface resistance of poly(ether ether ketone)/multiwalled carbon nanotubes (PEEK/MWCNT) composites restrict their use in an electronic field. To decrease the volume resistivity and surface resistance, we metalized the composites by electroless plating. The composites and metal coatings were characterized by SEM, XPS, AFM, EDX, and XRD spectroscopy. The swelling ratio of the composites, volume resistivity of two-side-coated composites, sheet resistance of plated composites, and adhesion between the coating and PEEK/MWCNT were tested. The results are as follows. A high roughness and a small swelling ratio were obtained by swelling in 18 mol/L H2SO4 for 3 min. Most of the MWCNT on the surface were still wrapped with PEEK after swelling. To expose the MWCNT, an environmentally friendly and effective etchant (MnO2-NaH2PO 4-H2SO4) was used. After etching, not only were high roughness and partially exposed MWCNT obtained but also the percentage of hydrophilic groups on the surface was increased. A dense cauliflower-like Ni-P coating was produced, and the exposed MWCNT were embedded in the metal coating after electroless plating for 20 min. The coating exhibited an amorphous structure with a phosphorus content of 11.21 wt %. The volume resistivity of two-side-coated PEEK/MWCNT dropped sharply to 38 Ω·m after electroless plating for 5 min. The sheet resistance decreased with increasing the electroless-plating time, and it dropped to 0.88 Ω/square after electroless plating for 40 min. The adhesion of the coating reached the highest 5 B scale (ASTM D3359) and could even undergo the test 20 times. © 2013 American Chemical Society.
Zhai T.,Tianjin University of Technology |
Di L.,Tianjin Medical College |
Yang D.,Tianjin University of Technology
Electronic Materials Letters | Year: 2014
In order to improve electromagnetic shielding property of poly (ether ether ketone)/carbon nanotubes composite, a nickel-phosphorus coating was covered on the composite by electroless plating. The morphologies of the substrates and the coatings were characterized by SEM. XPS was performed to analyze the surface composition and chemical states before and after chemical etching. The results showed that lots of microscopic holes appeared and evenly distributed on the surface, and the concentration of hydrophilic groups on the surface increased after the composite was etched. Thermal shock test showed that the adhesive strength between the coating and the composite was good. © 2014 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.
Di L.,Tianjin Medical College |
Liu B.,Tianjin Medical College |
Song J.,Tianjin University |
Shan D.,Tianjin University |
Yang D.-A.,Tianjin University
Applied Surface Science | Year: 2011
Poly(ether ether ketone)/carbon fiber composites (PEEK/Cf) were chemical etched by Cr2O3/H2SO4 solution, electroless plated with copper and then electroplated with nickel. The effects of chemical etching time and temperature on the adhesive strength between PEEK/Cf and Cu/Ni layers were studied by thermal shock method. The electrical resistance of some samples was measured. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface composition and functional groups. Scanning electron microscopy (SEM) was performed to observe the surface morphology of the composite, the chemical etched sample, the plated sample and the peeled metal layer. The results indicated that CO bond increased after chemical etching. With the increasing of etching temperature and time, more and more cracks and partially exposed carbon fibers appeared at the surface of PEEK/Cf composites, and the adhesive strength increased consequently. When the composites were etched at 60 °C for 25 min and at 70-80 °C for more than 15 min, the Cu/Ni metallization layer could withstand four thermal shock cycles without bubbling, and the electrical resistivity of the metal layer of these samples increased with the increasing of etching temperature and time. © 2010 Elsevier B.V.
Wang Y.,Tianjin Medical College
Advanced Materials Research | Year: 2014
Hydrodynamics in a liquid-liquid slug flow in a T-junction microchannel of 600μm diameter, operated under a squeezing regime, was simulated with the computational fluid dynamics method. The slug flow generation simulated shows very good agreement with experimental snapshots where the clear slug formation takes place in the vicinity of the T-junction. The internal circulation within each slug was also obtained, which could make us better understand the hydrodynamics of liquid-liquid slug flow in microchannel. © (2014) Trans Tech Publications, Switzerland.
Wang Y.,Tianjin Medical College
MATEC Web of Conferences | Year: 2016
Bi2MoO6 nanoplates with different sizes have been controllably fabricated by citric acid (CA) assisted hydrothermal process. The effects of CA on the morphology of Bi2MoO6 nanoplates have also been investigated. It is found that CA has a critical role in the crystallinity and size of Bi2MoO6 nanoplates. On the basis of XRD analysis and SEM observation of the products, the mechanism for CA assisted hydrothermal synthesis of the Bi2MoO6 nanoplates is discussed. The photocatalytic activity of as-prepared Bi2MoO6 was evaluated by the degradation of RhB dye in water, and the sample prepared when the amount of CA was 2.5mmol exhibited the highest photocatalytic activity. © The Authors, published by EDP Sciences, 2016.
Su J.,Tianjin Medical University |
Zhang A.,Tianjin Medical University |
Shi Z.,Tianjin Medical University |
Ma F.,Tianjin Medical College |
And 5 more authors.
International Journal of Oncology | Year: 2012
The Wnt/β-catenin signaling pathway is crucial for human organ development and is involved in tumor progression of many cancers. Accumulating evidence suggests that the expression of β-catenin is, in part, regulated by specific microRNAs (miRNAs). The purpose of this study was to determine the expression of a recently identified epithelial to mesenchymal transition (EMT)-associated tumor suppressor microRNA (miR)-200a, in cancer cells. We also aimed to identify specific miR-200a target genes and to investigate the antitumor effects of miR-200a on the Wnt/β-catenin signaling pathway. We employed TOP/FOP flash luciferase assays to identify the effect of miR-200a on the Wnt/β-catenin pathway and we confirmed our observations using fluorescence microscopy. To determine target genes of miR-200a, a 3′ untranslated region (3′ UTR) luciferase assay was performed. Cell viability, invasion and wound healing assays were carried out for functional analysis after miRNA transfection. We further investigated the role of miR-200a in EMT by Western blot analysis. We found fluctuation in the expression of miR-200a that was accompanied by changes in the expression of members of the Wnt/β-catenin signaling pathway. We also determined that miR-200a can directly interact with the 3′ UTR of CTNNB1 (the gene that encodes β-catenin) to suppress Wnt/β-catenin signaling. MiR-200a could also influence the biological activities of SGC790 and U251 cells. Our results demonstrate that miR-200a is a new tumor suppressor that can regulate the activity of the Wnt/β-catenin signaling pathway via two mechanisms. MiR-200a is a candidate target for tumor treatment via its regulation of the Wnt/β-catenin signaling pathway.
Li Y.Q.,Tianjin Medical University |
Shan Z.C.,Tianjin Medical College
Journal of Oral and Maxillofacial Surgery | Year: 2011
Purpose: The aim of the present study was to investigate the efficacy of microbial fiber membrane-Flagyl (MF-FLA) on facilitating hemostasis and wound healing and its anti-inflammatory ability after tooth extraction. Materials and Methods: For the animal experiment, 60 healthy male rabbits were randomly divided into control and treatment groups. Each group included 5 subgroups corresponding to different experimental periods (1, 2, 4, 8, and 12 weeks) and each subgroup had 6 rabbits. After the different experimental periods, the rabbits were killed, and the mandible was removed for histologic examination and analysis. For the human trial, 80 patients (32 males and 48 females; age range, 13 to 32 years), who were undergoing orthodontic treatment and who had undergone bilateral extraction of teeth were included. For every patient, the left tooth socket was treated with biting gauze for 30 to 60 minutes as the control group. The right fossa was covered with MF-FLA as the treatment group. The wound was inspected visually, its depth was measured, and radiographs were taken at the different experimental periods (1, 2, 4, 8, and 12 weeks) to evaluate the wound healing effect. Results: In the animal experiment, the results of the histologic examination indicated MF-FLA could facilitate the growth of fibroblasts and osteoblasts and inhibit inflammatory cells. In the human trial, the clinical observation indicated that the MF-FLA treatment showed better hemostatic ability than the biting gauze. After 4 weeks, the wound depth of the control and treatment groups was 3.08 ± 0.05 mm and 1.26 ± 1.06 mm (P < .01), respectively. The radiographs showed that the treatment group was superior to control group in the degree and rate of wound healing. Conclusion: The results of our study have shown that the MF-FLA can promote early wound healing and reduce the incidence of postextraction complications because of its biocompatibility, isolating and anti-inflammatory ability, and supporting the formation of blood clot in the tooth socket. © 2011 American Association of Oral and Maxillofacial Surgeons.
Fan X.,Shandong University |
Lv F.,Tianjin Medical College
European Journal of Cardiovascular Nursing | Year: 2014
Background: Self-efficacy is crucial to the management of chronic disease. However, little is known about self-efficacy for managing chronic disease in patients with chronic heart failure. Aim: The purpose of this study was to determine the incidence of inadequate self-efficacy for managing chronic disease and to identify the associated psychosocial factors in Chinese patients with chronic heart failure. Methods: A cross-sectional design was used. One hundred and fifty-nine chronic heart failure patients (mean age 63 years, 53% female) completed instruments related to self-efficacy for managing chronic disease, general self-efficacy, anxiety and depression, perceived social support, and demographic/clinical variables. Results: Of 159 patients, 46 patients (29%) had inadequate self-efficacy for managing chronic disease (the mean score on the Self-efficacy for Managing Chronic Disease Six-Item Scale (SECD6) was<7). The scores for general self-efficacy and perceived social support were positively correlated with the mean SECD6 score (p<0.01), whereas the scores for anxiety and depression were negatively correlated with the mean SECD6 score (p<0.01). Multiple linear regression analysis revealed that the factors associated with self-efficacy for managing chronic disease were general self-efficacy, depression and perceived social support, and three factors accounted for 29% of the variance. Conclusions: In Chinese patients with chronic heart failure, the prevalence of inadequate self-efficacy for managing chronic disease is high; general self-efficacy, depression and perceived social support are independent factors associated with self-efficacy for managing chronic disease. The screening of patients' self-efficacy and the implementation of relevant interventions may be beneficial to the promotion of self-management. © 2016 European Society of Cardiology.
Song F.J.,Tianjin Medical College
Zhonghua yi xue za zhi | Year: 2010
To analyze the trend of the incidence of prostate cancer in urban Tianjin area between 1981 and 2004 so as to provide scientific rationales for the prevention and control of prostate cancer. The data of prostate cancer cases were provided by the Tianjin Cancer Registry. The SAS system V9 was used to calculate the crude incidence, age-adjusted incidence and age specific incidence of prostate cancer in Tianjin between 1981 and 2004. And the Join point 3.0 software was used to analyze secular trends. Between 1981 and 2004, a total of 1060 prostate cancer cases were diagnosed in Tianjin. And the age-adjusted incidence rate was 2.84/100 000 in 2004. The incidence of prostate cancer showed 3 incremental stages during the 24-year period at an annual average of 4.02%. An aging trend was observed for prostate cancer patients. The elder patients had a faster increment in incidence. Specifically, it increased annually at 4.63% for age group 65 - 74 year versus 5.18% for age group 75 years or more. Despite a low incidence of prostate cancer in Tianjin, it is increasing at a fast rate. The prevention and control of prostate cancer should be strengthened.
Feng R.H.,Tianjin Medical College
Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology | Year: 2013
To investigate how transient low dose of hydroperoxide pretreatment prevents cardiac ischemia/reperfusion injury. SD rats were divided into 4 groups: sham operation (Sham), standard ischemia/reperfusion (I/R), ischemic preconditioning (IPC) and IR preceded by low H2O2 treatment. Cardiac function and injury parameter were compared among groups. IPC protected reperfusion injury and improved cardiac function. Low H2O2 treatment played a role in cardioprotection similar to IPC. Low H2O2 was indeed generated in the early phase of simulated ischemia and attenuated cytochrome c release induced by high Ca2+ in isolated mitochondria. Low H2O2 plays a critical role in cardioprotection probably by inhibiting mitochondrial permeability transition.